20th International Conference on Electromagnetic Isotope Separators and Related Topics (EMISXX)

19 Oct 2025, 08:00 → 24 Oct 2025, 18:00 America/Vancouver

Chateau Fairmont Whistler

Monika Stachura (TRIUMF), Nigel Smith (TRIUMF)

TRIUMF, Canada's national particle accelerator centre, is proud to host the 20th International Conference on Electromagnetic Isotope Separators and Related Topics (EMISXX) at Fairmont Chateau in Whistler from October 19 - 24, 2025.

As per its tradition, EMISXX aims to bring together researchers from across different fields, working on electromagnetic separators and related nuclear science, to discuss topics of:

• Isotope production, target, and ion source techniques
• Techniques related to high-power radioactive ion beam production
• Low-energy and in-flight separators
• Storage rings
• Ion guide, gas catcher, and beam manipulation techniques
• Ion optics and spectrometers
• Ion traps and laser techniques
• Instrumentation for radioactive ion beam experiments
• Applications of radioactive ion beams 
• Machine Learning and AI

 

Conference Program at a Glance

We look forward to seeing you there!

 

EMISXX2025- Exhibitor Package.pdf

EMISXX2025- Poster - 2nd circular.pdf

EMISXX2025_Sponsorship_Package.pdf

Monday, 20 October ¶

Plenary¶

1 Opening Remarks¶

Speaker: Dr Nigel Smith (TRIUMF)

2 High-power radioactive-ion-beam production and separation at FRIB¶

The Facility for Rare Isotope Beams, FRIB, started operation in May 2022. Since then, over 400 rare isotope beams have been separated and used in 58 experiments ranging from nuclear structure to creation of generators for medical diagnostics. The FRIB superconducting LINAC has provided primary beams ranging from ${}^{18}$O to ${}^{238}$U at energies from 130 MeV/u to 290 MeV/u. Rare isotope beams are formed in-flight using the Advanced Rare Isotope Separator, ARIS. ARIS incorporates a number of features, including infrastructure to operate at 400 kW, momentum compression to better match rare isotope beams to the subsequent experiments, and vertical and horizontal dispersive sections. So far, 12 new isotopes have been identified at FRIB, including ${}^{71}$Cr, which is predicted to be weakly bound. The talk will review the features of ARIS along with operational experience and first results.

Speaker: Bradley Sherrill (FRIB)

3 Proof-of-principle of in-trap laser polarization of Mg-23 ions with MORA at IGISOL¶

The MORA project (Matter’s Origin from Radioactivity) is an experimental setup dedicated to measure the triple-correlation parameter D in the nuclear beta decay of ${}^{23}$Mg and ${}^{39}$Ca. The $D$ correlation is a triple correlation between the spin of the decaying nucleus, the momentum of the emitted electron or positron, and the momentum of the emitted neutrino in mixed Fermi and Gamow-Teller transitions. The $D$ parameter is sensitive to physics beyond Standard Model, allowing to probe charge-parity (CP) violation mechanisms as a condition to matter-antimatter imbalance [1].

MORA consists of a transparent Paul trap and an octagonal arrangement of detectors mounted around it for positron and recoil ion detection. Trapped ${}^{23}$Mg ions are polarized with lasers and then let to decay while observing emitted particles. The degree of polarization is continuously monitored with silicon detectors [2].

In this contribution, the proof-of-principle of the in-trap laser polarization technique will be reported. The measurements were performed in the accelerator laboratory of University of Jyvaskyla, Finland, in IGISOL facility.

[1] A. Falkowski, A. Rodriquez-Sanchez, EPJC 82 (2022) 1134.
[2] N. Goyal et al., Performance of the MORA Apparatus for Testing Time-Reversal Invariance in Nuclear Beta Decay, arXiv:2504.16957v1 (2025).

Speaker: Tommi Eronen (University of Jyvaskyla)

Health Break¶

Isotope production, Targets and Ion Sources¶

4 Development of molecular beams at ISOLDE¶

Speaker: Mia Au (CERN)

5 MNT reactions with slowed-down relativistic beams – on a pathway to heavy-ion Coulomb barrier reactions with secondary beams¶

The properties of heavy neutron-rich nuclei are critical to explain the formation and existence of heavy elements in the universe. However, it is well known that certain regions on the nuclear chart, particularly those heavier and more neutron-rich than the heaviest stable primary beams, i.e., ${}^{238}$U, cannot be accessed using conventional production methods. Among the alternative approaches, multinucleon transfer (MNT) reactions have emerged as the most promising mechanism for reaching these challenging regions. MNT reactions also offer an efficient route for producing exotic isotopes along the line 𝑁=126, which are relevant to the origin of the third abundance peak in the rapid neutron-capture process (r-process). Realizing the full potential of this method will require the use of neutron-rich secondary beams.
To explore this potential, the Super-FRS experiment collaboration has started a program to conduct MNT experiments at GSI/FAIR. These experiments will utilize both stable and, eventually, secondary beams at the FRS and the Super-FRS. The reaction targets are located inside the cryogenic stopping cell, and the identification of the reaction products is performed using the high-resolution and broadband MR-TOF-MS. Tests at the FRS Ion Catcher have confirmed the feasibility of this experimental design [1]. The future Super-FRS Ion Catcher, equipped with a larger stopping cell, will enable MNT studies with highly intense beams.
This contribution will present preliminary results obtained using 238U stable beams, as well as further tests and plans involving secondary beams.
[1] A. Mollaebrahimi et al., NPA, 1057 (2025) 123041

Speaker: Timo Dickel

6 Expanding User Capabilities and Increasing Reliability at TRIUMF-ISAC¶

The Isotope Separator and Accelerator (ISAC) facility at TRIUMF is a world class laboratory for the production and delivery of rare isotopes. ISAC uses the isotope separation on-line (ISOL) method to create a variety of exotic isotopes, utilizing high-intensity proton beams from TRIUMF’s 500 MeV cyclotron. The proton beam is impinged on a thick target which sits inside a target assembly. The target assembly sits inside a target module which is responsible for delivering all services (high voltage, high current, low voltage signals, vacuum, cooling and gas injection) from the target stations, through a section of shielding, to the operating target.

Maintaining reliable beam delivery to experiments is a cornerstone of ISAC’s mission, which becomes more challenging as the facility ages and the demand for new beams and new operational modes increases. This contribution will give an overview of recent changes at ISAC, highlighting efforts to increase reliability through improvements to high voltage operation and infrastructure, and a first-time target module refurbishment program. In addition we will discuss expanded options for users made possible through new target designs, improved laser ionization schemes and new methods of operation.

Speaker: Carla Babcock (TRIUMF)

7 The study of the high-spin isomer beam production via the fragmentation reaction at 350 MeV/u.¶

High-spin nuclear isomers in rare unstable beams are important for studies in nuclear structure, nuclear astrophysics, and applied research. While fragmentation reactions, widely used at in-flight rare-isotope beam facilities, can produce a diverse range of nuclides, the selective and high-intensity production and separation of specific isomer states remain challenging. This study aimed to experimentally investigate the correlation between parallel momentum transfer and angular momentum transfer in fragmentation reactions, contributing to the development of selective beam production techniques for isomer states.
We focused particularly on previous studies [1] that showed an increase in the isomer ratio by selecting the tail of the fragment momentum distribution, with the goal of clarifying its physical origin. In this research, we investigated the correlation between angular momentum and parallel momentum transfer by selecting events from high-spin isomer states and comparing their momentum distributions with those of events primarily in the ground state.
The experiment was conducted at the SB2 beamline of the High-Energy Heavy-Ion Accelerator Facility (HIMAC). Primary beams of ${}^{58}$Ni and ${}^{59}$Co accelerated to 350 MeV/u irradiated a 14 mm thick ${}^9$Be target to produce nuclides around ${}^{52}$Fe through fragmentation reactions. The produced fragments were separated by a fragment
separator (two dipole magnets) and identified using the time-of-flight (ToF), energy loss($\mathrm{\Delta }$E), and magnetic rigidity (B$\rho$) method. Among the identified nuclides, de-excitation gamma rays from high-spin isomers ${}^{52m}$Fe(12${}^{+}$), ${}^{53m}$Fe(19/2${}^{-}$) and ${}^{54m}$Co(7${}^{+}$) were measured using four Ge detectors placed at the end of the
flight path with the particle identification.
As a result of the analysis, a clear tendency was observed for the relative production of high-spin isomers to increase in the region of large momentum transfer away from the center of the fragment momentum distribution (the tail of the distribution), consistent with previous studies [2][3]. Furthermore, by comparing the measured properties of multiple isomer states, a clear positive correlation was found between the magnitude of the imparted angular momentum and the parallel momentum transfer.
In this presentation, we will report these experimental results in detail and discuss the current understanding of the angular momentum generation mechanism in fragmentation reactions and its potential application to the production of high-purity, high-intensity isomer beams.

[1] Schmidt-Ott, et al., Zeitschrift für Physik 350 215-219 (1994)
[2] Daugas, J. M. et al., Phys. Rev. C 63 064609 (2001)
[3] M. Notani et al., Phys. Rev. C 76 044605 (2007)

Speaker: Keita Kawata (RCNP)

Lunch¶

Facilities I¶

8 RIB production & Overview of RAON¶

Speaker: Dr TAEKSU SHIN (IRIS, IBS)

9 TRIUMF-ARIEL: Tripling TRIUMF's RIB capabilities¶

TRIUMF's ISAC facility operates ISOL targets under high-power particle irradiation up to 500 MeV and 100 μA of current, producing Radioactive Ion Beams (RIBs) for Canadians and international nuclear and particle physics experiments. The ARIEL facility (Advanced Rare IsotopE Laboratory) is currently under construction with the objective to add two RIBs, in addition to the RIB already being produced by the existing ISAC facility. One ARIEL station will receive a driver beam of 500 MeV protons, up to 100 μA from TRIUMF’s H- cyclotron. The other ARIEL station will utilize an electron beam from the new superconducting linear accelerator, with energy up to 35 MeV and up to 100 kW beam power. The addition of these two ISOL targets enables the delivery of three simultaneous RIB beams to different experiments, while concurrently producing radioisotopes for medical applications.
This contribution will describe the target station and its completion status, and will highlight the recent qualification tests that have been performed on its core components in our offline facility. The predicted beam intensities from the additional two stations will be presented, highlighting the main strengths and weaknesses of this combined facility. Moreover, the current status of the ARIEL facilities will be discussed, along with the roadmap their completion and ramp-up.

Speaker: Luca Egoriti (TRIUMF)

10 Development of a new SPIRAL1 fragmentation target to enhance and expand radioactive isotope production at GANIL¶

The growing demand for more intense and diverse exotic beams has driven the development of a new high-temperature ISOL (Isotope Separation On-Line) target for the SPIRAL1 (Système de Production d’Ions Radioactifs Accélérés en Ligne) facility at GANIL (Grand Accélérateur National d’Ions Lourds). The primary objective is to enhance the production yields of several radioactive isotopes of physical interest while ensuring compatibility with the thermal and mechanical constraints of the Target-Ion Source System (TISS).

Currently, radioactive isotopes at SPIRAL1 are produced using primary beams ranging from ${}^{12}$C to ${}^{238}$U (< 95 MeV/u, < $2\times {10}^{13}$ pps), impinging on a graphite target to induce beam fragmentation. To improve the production efficiency and expand the isotope diversity, alternative target materials are being investigated to replace graphite. This new target material will be used with a ${}^{12}$C primary beam to induce target fragmentation.

Several candidate materials—including Nb, ZrO${}_2$, and Y${}_2$O${}_3$—were selected based on bibliographic research of ISOL target materials and theoretical estimations of isotope production cross-sections. Their suitability is being assessed by analyzing diffusion and effusion characteristics using literature data. Numerical simulations will be carried out using a parametric thermal model developed in ANSYS to evaluate the steady-state temperature distribution within targets of different geometries and compositions. These simulations will provide an insight into the expected release efficiencies as the produced isotope effusion and diffusion depend of the material properties, thermal gradients, microstructure and geometry of the target. In parallel, high-temperature stability and chemical compatibility of the selected materials are being investigated to ensure reliable operation under SPIRAL1 conditions.

Based on these studies, a prototype target will be co-designed in collaboration with GANIL’s mechanical engineering division. This prototype aims to experimentally validate the thermal and mechanical performance of the proposed materials under realistic irradiation conditions. Iterative optimization informed by simulation data will guide the final geometry design.

This development is a key component of the broader effort to expand GANIL’s radioactive ion beam capabilities. It supports the long-term objective of delivering a wider range of exotic beams for nuclear physics and interdisciplinary research, including future experiments at the SPIRAL2-DESIR low-energy facility.

Speaker: Sophie Hurier (GANIL)

11 ISOL@MYRRHA recent advancements¶

The ISOL facility under development by the Belgian Nuclear Research Centre (SCK CEN), ISOL@MYRRHA, will leverage a fraction of the MYRRHA accelerator's proton beam to produce radioactive ion beams (RIBs). Already built as part of MYRRHA phase 1, the facility will receive in this phase a 100-MeV proton beam, up to 0.5 mA.

With the aim of producing high-intensity RIBs for several research programs, the performance of the production targets is a critical parameter. This contribution will present developments on the target design for the initial deployment phase of the facility known as Day-1. Investigations on Day – 1 target materials will also be covered. Furthermore, the latest progress will be discussed for the design and engineering of key components such as the proton beam window and the target vessel. These must be capable of withstanding the demanding operational conditions of ISOL@MYRRHA Day-1.

To provide users with information on nuclides that can be produced and identify the better suited targets and ion sources in terms of yields and beam purity, a database of production yields is being developed. The methodology for building this database along with its two-part structure will be shown. Furthermore, the findings of this study will also be discussed.

Lastly, highlights will be presented for the ongoing efforts to establish and commission test stands and offline setups. These setups are essential for developing target materials, target components, ion sources, beam windows and laser-ionization schemes.

Speaker: Donald Houngbo (SCK-CEN)

12 The Quest for Beryllium-14¶

A milestone of the 2024 ISAC RIB campaign at TRIUMF was the successful extraction and measurement of 14Be at the GRIFFIN detector. The interest for 14Be production in ISAC is mainly driven by the beta-decay studies of halo nuclei and their mass measurements. Due to the low production rate of 14Be and its very short half-life (4.35 ms), this rare exotic isotope challenges the limits of the ISOL targets and laser ion sources.
To achieve the goal of 14Be production a new tantalum target was optimized for fast isotope releases, heat transfer, and in target production. Analysis, simulations and experimental studies led to the development of a target with thinner tantalum foils and a total target thickness 40% of a standard ISAC target. The proton beam was rotated on the tantalum target for a more uniform temperature distribution, at an unprecedented high intensity of 85 micro-amperes (40.8 kW). An optical diagnostic to measure and monitor the temperature of the target in real time was used during the target run.
This work reports on the 14Be campaign, the target design, real-time diagnostics, beam delivery techniques and yields of other short-lived isotopes such as 12Be, 11Li, 9Li and 8Li.

Speaker: Aurelia Laxdal (TRIUMF)

Health Break¶

Facilities II¶

13 SPES Facility first ISOL RIB production¶

Speaker: Tommaso Marchi (INFN)

14 HIRIBL- Fragment separator of HIAF¶

Speaker: Hooi Jin Ong (IMP)

15 BuRI‑To & PIPERADE commissioning for DESIR¶

The forthcoming DESIR facility will soon open new perspectives for low-energy nuclear physics experiments at GANIL. Radioactive ion beams from SPIRAL1 and S³ facilities, including very exotic isotopes produced at competitive rates for dedicated studies, are set to be delivered at low energy, low emittance and with high purity to various mass measurement, decay spectroscopy or laser spectroscopy experiments.

Two setups currently developed at LP2i Bordeaux are key parts of this objective. BuRI‑To (“Bunching Radioactive Ions To…”, known as “GPIB” while it is being commissioned in Bordeaux) is a radiofrequency quadrupole cooler buncher to be installed at the entrance of the DESIR hall. It will deliver either continuous or bunched beams, with low emittance and high efficiency, adapted to the specific needs of each experiment (adapted bunch length, energy dispersion, etc.).
Also under development at Bordeaux, PIPERADE (« PIèges de PEnning pour les RAdionucléides à DESIR ») is a double Penning trap which has a double purpose in the DESIR hall. Located shortly downstream of BuRI‑To, it will allow high-resolution mass purification of the radioactive ion beams, with resolving powers up to 10⁷. This enables the separation of low-lying isomeric states from their ground states and therefore allows isomerically-pure beams to be exploited by the downstream experiments in the DESIR hall. In addition, PIPERADE is also designed for high-precision mass measurements with the use of Time-of-Flight Ion-Cyclotron Resonance (ToF-ICR) and Phase-Imaging Ion-Cyclotron Resonance (PI-ICR) techniques.

This presentation will provide an overview on the commissioning work on both setups in Bordeaux, before their move to GANIL planned to start in 2026.

Speaker: Corentin Roumegou (LP2iB (CNRS))

16 The production of the first fission nuclear radioactive beam of BRISOL facility¶

The Beijing Radioactive ion beam facility Isotope Separator On-Line（BRISOL）is a radioactive ion beam facility based on a 100MeV cyclotron providing 200μA proton beam bombarding the thick target to produce radioactive nuclei, which are transferred into an ion source to produce singly charged ion beams. A surface ion source had been developed for BRISOL, and the first radioactive beams (37K+, 38K+, 42K+, etc.) were produced by bombarding a CaO target with a 100MeV proton beam from the cyclotron in 2015. A FEBIAD ion source with MgO target are successful used to the first physics experiments, including the decay study of 20Na with the energy of 110keV and the elastic scattering study of 21Na and 22Na beams, post-accelerated by a 13MV tandem. The refractory carbide targets such as SiC, LaC2 and UC2 are also developing for more radioactive beams. The first online test of SiC target has been completed recently, and radioactivity beams of 25Al, 26Al, and 28Al were produced. The radioactive nuclear beams of rubidium and cesium were generated using uranium carbide targets and used to study the decay characteristics of neutron rich beams. The details of the development of BRISOL facility and the online experimental results will be presented in this paper.

Speaker: Bing Tang

17 The TATTOOS Facility¶

The TATTOOS Facility

Stuart Warren*, R. Eichler, M. Hartmann, A. Ivanov, S. Jollet, H. Jöhri, R. Hübscher, D. Kiselev, D. Laube, R. Martinie, M. Mostamand, D. Reggiani, J. Snuverink, N. van der Meulen, U. Wellenkam

Paul Scherrer Institute, PSI Forschungsstrasse 111, 5232 Villigen PSI, Switzerland

Stuart.warren@psi.ch

TATTOOS (Targeted Alpha Tumour Therapy and Other Oncological Solutions) is the next major installation at the Paul Scherrer Institute as part of the IMPACT project[1]. It envisages the use of the high intensity high energy proton beam from the ring cyclotron (HIPA, 590MeV 2.4 mA H+) to impinge on high Z targets for spallation produced radionuclides. The facility is, by design, a high throughput machine, with expected 100 uA proton beams impacting the target, producing a high yield of isotopes (>GBq Tb149) via spallation, online mass separation and laser ionization with less than 2% neighbouring mass contamination.

Here, we present the current status of the designs and layout for the core features of the facility; the high throughput electromagnetic separator with the moderate resolution of 3000 for typical surface source ion beams, the subsequent ion beamline systems and services, proposed collections, and proposed layout in the confined space of the site.

The facility aims to be the silver bullet in the production bottleneck of radionuclides for oncological solutions, bridging the gap between the technology and the clinical trial solution with medically relevant quantities of radionuclides.

[1] Eichler, R., Kiselev, D., Koschik, A., Knecht, A., van der Meulen, N., et Al (2022). IMPACT conceptual design report. (PSI Bericht, Report No.: 22-01). Paul Scherrer Institute.

Speaker: Stuart Warren (Paul Schreere Institute)

Welcome Reception (SLCC)¶

Tuesday, 21 October ¶

AM Session 3: Instrumentation for RIB experiments¶

18 Presence and Future of the MRTOF systems at RIBF, and new projects in East Asia¶

Tackling the increasing challenge to determine the mass of isotopes having low production yields and short half-lives, multi-reflection time-of- flight (MRTOF) mass spectrometry has grown from an initially rarely-used technology to the world’s most commonly-used method for measurements with a relative mass precision down to $\delta m/m={10}^{-8}$. This technology has been developed at RIKEN’s RIBF facility for about two decades in combination with gas-filled ion catchers for low-energy access of isotopes produced by the in-flight method.
In the recent years, three independent systems operating at different access points at RIBF, have provided substantial data in the medium- and heavy-mass region of the nuclear chart, reaching out to the superheavy nuclides. Recent achievements like high mass resolving power [1] followed by the development of α/β-TOF detectors [2] and in-MRTOF ion selection have tremendously increased the selectivity of the systems. The combined application allows for background-free identification of the rarest isotopes. In this contribution, I will give a short overview about the success of MRTOF atomic mass measurements using BigRIPS in the recent past [3-5], and report new achievements from 2024. I will discuss the instrumentation plans, with a view to future MRTOF systems in other facilities of East Asia, and the combination of mass measurements with established setups for $\beta -\gamma$ spectroscopy using a through-beam gas cell.

References:
[1] M. Rosenbusch et al., Nucl. Instrum. Meth. A 1047, 167824 (2023).
[2] T. Niwase et al., Theo. Exp. Phys. 2023(3), 031H01 (2023).
[3] S. Iimura et al., Phys. Rev. Lett. 130, 012501 (2023).
[4] D. S. Hou et al., Phys. Rev. C 108, 054312 (2023).
[5] W. Xian, S. Chen et al., Phys. Rev. C. 109, 035804 (2023).

Speaker: Marco Rosenbusch (RIKEN Nishina Center for Accelerator-Based Science)

19 Mass measurements of the heaviest elements with the SHIPTRAP mass spectrometer at GSI¶

Investigating the boundaries of the nuclear chart and understanding the structure of the heaviest elements are at the forefront of nuclear physics. The existence of the superheavy nuclei is intimately linked to nuclear shell effects which counteract Coulomb repulsion and therefore hinder spontaneous fission. In the region of heavy deformed nuclei weak shell gaps arise around $Z$=100 and $N$=152 as well as around $Z$=108 and $N$=162. However, the extension of these gaps and their impact on the structure of these exotic nuclei, especially the most neutron-rich ones, is not yet fully understood, as most of the relevant nuclear systems are not experimentally addressed due to limited production capabilities, i.e. available beam-target combinations and/or corresponding low yields. Moreover, heavy and superheavy nuclides feature often metastable excited states with half-lives that can exceed the one of the ground state. Long-lived isomeric states can have excitation energies of only few tens of keV or below, therefore, their identification is challenging, especially in decay-based measurements.

On the other hand, Penning-trap mass spectrometry allows the experimental determination of the binding energy and, when applied to isotopic chains crossing shell gaps can provide information concerning the evolution of the shell gap strength without the detailed knowledge of the structure of the nuclei under study. Moreover, mass measurements with Penning traps feature sufficient resolving power to allow the separation of isomeric states when they are populated in the same reaction as the ground state. Their excitation energy can then be measured precisely.

In recent years, we have established tailored and highly sensitive experimental methods allowing us to extend the reach of Penning-trap mass spectrometry with the SHIPTRAP setup to heavy elements well beyond uranium. In this talk a review of the latest experimental campaigns will be presented.

Speaker: Dr Francesca Giacoppo (GSI Helmholtzzentrum für Schwerionenforschung GmbH - Darmstadt, Germany)

20 Development of the Fast Plastic Scintillation Detector for High-Resolution Velocity β Measurements in a Short Flight Path¶

Improving the resolution of particle identification is a crucial challenge in nuclear physics experiments using heavy ion beams. Among the important parameters for particle identification is the particle velocity, which is generally determined by measuring the time of flight (TOF) of charged particles. Enhancing the resolution of TOF measurements can be achieved by either extending the flight path or improving the time resolution of the timing detector. In particular, improving the time resolution allows for a more compact experimental setup, making it applicable to a wide range of nuclear experiments.
In this study, we developed a plastic scintillation counter with excellent time resolution by combining a fast plastic scintillator with newly developed high-speed photomultiplier tubes (PMTs). Recently, HAMAMATSU PHOTONICS K.K. developed a new series of ultra-fast PMTs that place the anode potential near the first dynode. On the other hand, ELIJEN TECHNOLOGY also developed ultra-fast scintillators by adding trace amounts of benzophenone as a quenching agent. We assembled a detector by mounting two of these PMTs on either side of the rectangular ultra-fast scintillator.
We evaluated the performance of the detector using a ${}^{132}\mathrm{Xe}$ primary beam at 420 AMeV at the HIMAC synchrotron accelerator facility at the National Institutes for Quantum Science and Technology. Measurements were performed by varying parameters such as the scintillator size, the applied high voltage to the PMTs, and the discriminator threshold to determine the optimal conditions. As a result, we achieved a time resolution of approximately $\sigma \sim 5\text{ps}$. In this study, we discuss the final results of the time resolution of the developed fast plastic scintillation detector and how it can be applied to physical experiments.

Speaker: Mr Soshi Ishitani (University of Osaka)

21 Online commissioning and current status of CLaSsy at RAON¶

The online commissioning experiments of CLaSsy, a Collinear Laser Spectroscopy setup at RAON, were conducted at the end of 2024 with KNUE and CENS collaborators, observing the optical D1 and D2 transitions for sodium isotopes (${}^{21}Na$, ${}^{22}Na$ and ${}^{23}Na$). The isotopes were provided in the form of bunched beams with a repetition rate of 10 Hz using the Radio Frequency Quadrupole-Cooler Buncher (RFQ-CB) at the ISOL facility at RAON. The collinear and anti-collinear geometries were alternately employed to measure the fluorescence spectra as a function of the acceleration voltage of the post accelerator. As a result, the input ion beam energy was precisely measured from Doppler shifts of the two spectra in different geometries. The kinematic compression of Doppler broadening at ~20 keV beam energy provided a sufficient spectral resolution to observe the hyperfine structure of the ${}^2{S}_{1/2}$ ground state and the ${}^2{P}_{1/2}$ excited state, whereas the resolution for the hyperfine splitting of the ${}^2{P}_{2/3}$ excited state was limited. To improve the spectroscopic resolution, a high-resolution laser spectroscopy with two independent laser beams in a combined collinear and anti-collinear geometry has been under development. In this talk, we present the commissioning results and an outlook on future experiments of CLaSsy.

Speaker: Jaehyun Song (Institute for Rare Isotope Science (IRIS))

Health Break¶

Ion traps & laser techniques¶

22 Nuclear structure studies by collinear laser spectroscopy¶

The study of radioactive isotopes is essential for deepening our understanding of the nuclear force, particularly in systems with extreme proton-to-neutron ratios. Efforts to unravel how collective phenomena emerge from complex many-body interactions continue to drive progress in nuclear and atomic theory, as well as in the techniques for producing and probing radioactive ion beams. Among these, collinear laser spectroscopy has emerged as a particularly powerful method for extracting key nuclear properties—such as spin, nuclear moments, and size—thereby providing crucial insights into the nature of nuclear interactions. Collinear laser spectroscopy supports a wide range of ion beam preparation and detection schemes. This flexibility enables ongoing innovation and the development of customised experimental approaches to study isotopes at the limits of nuclear stability.

In this talk, I will present recent findings from collinear laser spectroscopy that have advanced our understanding of nuclear structure. These examples will be chosen to highlight the key role of these ongoing technical developments, along with a perspective on future directions in the field. The role of our new development laboratory at KU Leuven, intended to support experiments in current and next-generation laboratories, will also be highlighted.

Speaker: Agi Koszorus (KU Leuven, SCK CEN)

23 Development of a high-resolution and high-sensitivity collinear resonance ionization spectroscopy system¶

Nuclear properties are closely connected to nuclear structure and nucleon-nucleon interactions, making them essential for exploring various novel phenomena that emerge in exotic nuclei. Laser spectroscopy is a powerful technique for investigating nuclear properties of unstable nuclei by probing the hyperfine structure (HFS) of their surrounding electrons. Such HFS effect contributes only about one part in a million of the total transition frequency, thus requiring high-resolution measurement techniques. Furthermore, studying unstable nuclei poses further challenges due to their short lifetimes, low production yields, and significant isobaric contamination. Collinear resonance ionization spectroscopy stands out as a premier technique for exotic nuclei research due to its high resolution and high sensitivity [1].
Through the recent implementation of a radio-frequency quadrupole cooler-buncher [2] and a multi-step laser ionization technique, we have successfully established a high-resolution and high-sensitivity collinear resonance ionization laser spectroscopy system named PLASEN (Precision LAser Spectroscopy for Exotic Nuclei) at Peking University [3]. The entire system was fully characterized using a bunched Rb ion beam at an energy of 30 keV by measuring the HFS spectra of the D2 line for ${}^{85,87}$Rb isotopes. An overall efficiency exceeding 1:200 was achieved, along with a spectral resolution of approximately 100 MHz, which yields an experimental sensitivity sufficient for laser spectroscopy measurements of unstable nuclei at yields around 100 pps. The extracted properties of ${}^{85,87}$Rb agree well with the literature values, further confirming the reliability of the system.
In this talk, the details of PLASEN system will be presented, together with the results from the offline commission experiment for ${}^{85,87}$Rb isotopes. A planned online laser spectroscopy experiment using this setup at BRIF will also be discussed.

References:
[1] X. F. Yang, et al., Prog. Part. Nucl. Phys. 129 (2023) 104005.
[2] Y. S. Liu, et al. (2025). arXiv:2502.10740.
[3] H. R. Hu, et al. (2025). arXiv:2503.20637.
[4] T. J. Zhang, et al., Nucl. Instrum. Methods Phys. Res. Sect. B 463 (2020) 123–127

Speaker: Mr Hanrui Hu (Peking University)

24 Doppler and sympathetic cooling for the investigation of short-lived radionuclides¶

Ever since its introduction in the mid 1970s, laser cooling has become a fundamental technique to prepare and control ions and atoms for a wide range of precision experiments. In the realm of rare isotope science, for instance, specific atom species of short-lived radionuclides have been laser-cooled for fundamental-symmetries studies [1] or for measurements of hyperfine-structure constants [2] and nuclear charge radii [3].

Nevertheless, because of its simplicity and element-universality, buffer-gas cooling in a linear, room-temperature Paul trap is more commonly used at contemporary radioactive ion beam (RIB) facilities. Recent advances in experimental RIB techniques, especially in laser spectroscopy and mass spectrometry, would however strongly benefit from ion beams at much lower beam temperature as in principle attainable by laser cooling. In addition, sympathetic cooling of ions which are co-trapped with a laser-cooled ion species could open a path for a wide range of sub-Kelvin RIBs.

Within the MIRACLS low-energy apparatus, we demonstrate that laser cooling is compatible with the timescale imposed by short-lived radionuclides as well as with existing instrumentation at RIB facilities [4]. To this end, a beam of hot 24Mg+ ions is injected into a linear Paul trap in which the ions are cooled by a combination of a low-pressure buffer gas and a 10-mW, cw laser beam of ∼280 nm. Despite an initial kinetic energy of the incoming ions of several electronvolts at the trap’s entrance, temporal widths of the extracted ion bunch corresponding to an ion-beam temperature of around 6 K are obtained within a cooling time of 200 ms. Moreover, sympathetic cooling of co-trapped K+ and O2+ ions was demonstrated. As a first application, a laser-cooled ion bunch is transferred into a multi-reflection time-of-flight mass spectrometer. This improved the mass resolving power by a factor of 4.5 compared to conventional buffer-gas cooling.

This contribution will include the experimental results of our laser-cooling studies as well as a comparison to our 3D simulations of the cooling process which paved the way for further improvements of the technique. An outlook to future experiments with laser- and sympathetically cooled ions at radioactive ion beam facilities will be given.

[1] G. D. Sprouse and L. A. Orozco, Annu. Rev. Nucl. Part. Sci.. 47, 429 (1997)
J. A. Behr et al., Phys. Rev. Lett. 79, 375 (1997).
M. Trinczek et al., Phys. Rev. Lett. 90, 012501 (2003).
P. A. Vetter et al., Phys. Rev. C 77, 035502 (2008).
J. R. A. Pitcairn et al., RRC 79, 015501 (2009)
B. Fenker et al., Phys. Rev. Lett. 120, 062502 (2018)
[2] A. Takamine et al., Phys. Rev. Lett. 112, 162502 (2014)
[3] L. B. Wang et al., Phys. Rev. Lett. 93, 142501 (2004).
P. Mueller et al., Phys. Rev. Lett. 99, 252501 (2007).
[4] S. Sels, F.M. Maier et al., Phys. Rev. Research 4, 033229 (2022)

Speaker: Stephan Malbrunot-Ettenauer (TRIUMF)

25 Towards trapping of fast radioactive ions¶

To better understand key nuclear properties, tremendous effort has been put over the past decades into ab initio theoretical models [1], capable of reproducing experimental data with increasingly higher precision. Benchmarking these models requires precise measurements of key nuclear observables, among which electromagnetic moments and charge radii play complementary roles.

Measurements of these quantities can be obtained using different techniques, but the most accurate technique has been laser spectroscopy (LS). As an alternative to the well-established in-source and collinear laser spectroscopy methods, an offline beamline has been commissioned at KU Leuven to perform spectroscopy on trapped ions at Radioactive Ion Beam (RIB) facilities. This will substantially increase the laser-ion nteraction time from a few microseconds to multiple seconds, ultimately limited only by the half-life time of the radioactive ions. This enables the excitation of weak transitions, such as radiofrequency transitions within a hyperfine manifold [2], which will allow the extraction of electromagnetic moments beyond the electric quadrupole moment, such as the magnetic octupole moment. This will add another nuclear observable as a benchmark for nuclear theory and provide information on the proton distribution inside the nucleus.

This contribution will give an overview of the project and present the first results from our linear Paul trap, which includes the deceleration, trapping and laser cooling of Sr${}^{+}$ ions from 10 keV beam energy to a few K temperature. Additionally, first laser spectroscopy measurements with the laser-cooled ions will be discussed. Finally, an outlook on the upcoming developments in Leuven will be provided and prospects for implementation of this setup at RIB facilities will be explored.

References:

1. A. Ekstrom et al., Frontiers in Physics 11, 29094 (2023)
2. X. Yang et al., Physical Review A 90, 052516 (2014)

Speaker: Stefanos Pelonis (KU Leuven)

Lunch¶

Storage Rings¶

26 First electron scattering on RI beam at the SCRIT electron scattering facility¶

Electron scattering is a powerful tool for studying nuclear structure, because it allows model-independent studies of nuclear structure. For example, the charge density distribution of nuclei can be determined very accurately by electron elastic scattering. Therefore, electron scattering has been long awaited in the study of unstable nuclei, especially short-lived unstable nuclei.
There are only a few measurements of electron scattering on unstable nuclei which are long life isotopes. This is because it is difficult to prepare a large number of targets for more production-hard, short-lived unstable nuclei to achieve the required luminosity for electron scattering. To overcome such a situation, a new ion trapping method, Self-Confining Radioactive Isotope Ion Target (SCRIT) method, was developed.[1] After demonstrating the principle of the SCRIT method, the SCRIT electron scattering facility was constructed at RIKEN RI Beam Factory in 2009.[2] The SCRIT facility consists of an electron accelerator, an electron storage ring equipped with the SCRIT system, an online isotope separator, and an electron spectrometer besides the SCRIT system. Produced Radio Isotope (RI) beams are injected to the SCRIT system and RIs trapped inside the SCRIT system play as stationary targets. Electron beam stored in the ring are scattered from the RI targets and analyzed by the spectrometer.
After the success of the commissioning experiment using ${}^{132}$Xe [3] and the development of the RI production, the world's first electron scattering experiment using online-produced unstable nuclei was successfully conducted using ${}^{137}$Cs beam in 2022.[4] For the next stage, the upgrade of the SCRIT facility is underway for electron scattering off ${}^{132}$Sn, which is a iconic nuclei. In addition, various interesting physics programs have been proposed; photo absorption, isotope dependence of charge density distribution, forth-order moment of nuclear charge density to access neutron distribution radius, and more. In this contribution, we will report details of the first experiment, and the present status and perspective of the SCRIT project.
[1] M. Wakasugi, T. Suda, and Y. Yano, Nucl. Instr. and Meth. A532, 216 (2004).
[2] M. Wakasugi et al., Nucl. Instr. and Meth. B317, 668 (2013).
[3] K. Tsukada et al., Phys. Rev. Lett. 118, 262501 (2017).
[4] K. Tsukada et al., Phys. Rev. Lett. 131, 092502 (2023).

Speaker: Tetsuya Ohnishi (RIKEN Nishina Center)

27 Surrogate reaction in inverse kinematics at the ESR of the GSI/FAIR facility¶

Speaker: Wloch Boguslaw (LP23)

28 Present and Future Mass Measurement Methods of the Rare-RI Ring¶

Isochronous mass spectrometry (IMS) is one of mass measurement methods particularly effective for short-lived nuclei. In this method, a storage ring is used to measure the revolution time of the particles. Since the revolution times of the particles are proportional to the mass-to-charge ratios of the particles, the nuclear masses can be deduced using IMS. One of the storage rings for IMS is the Rare-RI Ring (R3) at the RIKEN RI beam factory. This device is in operation and has successfully measured the masses of rare isotopes [1].
Recently, we have upgraded the mass measurement method in R3 and are attempting to derive masses with smaller uncertainties. To improve the beam transport and statistical errors, two vertical steering magnets were installed upstream of R3. These magnets were tested in the previous experiment, and resulted in a seven times higher yield compared to that without the magnets. A new beam tuning method is also being studied to obtain the revolution time with high accuracy. In this beam tuning method, it is important to adjust the angle of the particles injected to R3. Finally, a new Schottky detector was installed in R3. This non-destructive detector aims to measure the magnetic rigidity of particles inside R3 and is expected to be a key device to improve the beam transport and/or more precise mass measurement in the future.
This presentation will first introduce a conventional mass measurement method of R3. Next, the principle and method of mass measurements currently under development will be discussed.

Speaker: Asahi Yano (Univ. of Tsukuba / RIKEN)

29 The low energy storage ring CRYRING@ESR - operational experience and beams available for experiments¶

Heavy, highly charged ions stored at low energy are ideal probes for various questions of modern physics that range from tests of QED, especially at high fields, to detailed investigations of nuclear reactions. CRYRING@ESR is a low energy storage ring transferred from Stockholm, Sweden, to Darmstadt in order to profit from the exceptional production capabilities of exotic ions at GSI, Darmstadt, Germany. Within the FAIR Phase 0 experiment program, CRYRING@ESR provides heavy, highly charged ions, as for instance U91+, to experiments. Additionally, a local injector has been used for commissioning and provides light, medium-charged ions.

CRYRING@ESR stores ions ranging from a few 100 keV/nucleon to a few MeV/nucleon. It is also equipped with one of the most elaborate electron coolers, especially suited to low energy. Such, the ions produced using the GSI accelerator chain can be decelerated, cooled, and - if needed - extracted. Taken into operation after the move from Stockholm and some serious refurbishment in 2018, it has been running routinely within the FAIR phase 0 program since 2020.

Experiments rely on the exceptional vacuum and a multitude of additional detectors and interaction regions. One region is dedicated to laser-ion beam interaction, while the other is equipped with a gas jet target and a transversal electron target. In combination with modern detectors like micro-calorimeters for X-rays or the CARME silicon strip array for particles produced in nuclear reactions, unique measurements at astrophysical relevant energies and systems have been performed already and are still ongoing.

In this contribution we will discuss the technical possibilities and limitations, the ion beams available from the GSI accelerator chain or the local injector, and its properties focussing particularly on the opportunities for experiments.

Speaker: Frank Herfurth (GSI Helmholtzentrum für Schwerionenforschung GmbH)

Health Break¶

Ion optics & spectrometers¶

30 FIONA ToF: a Time-of-Flight detector for studies of superheavy elements at Berkeley Lab¶

Superheavy elements tend to decay mostly by alpha decay and spontaneous fission and their detection and study often relies on the detection of the alpha particles and the fission products using silicon detectors. In addition, half-lives can be deduced through the timestamps of implantation and decay events. This is possible due to the fact that after production, the ions have 10s of MeV of energy, enough to be implanted beyond the dead layer of a typical Si wafer.

In Berkeley Lab, we produce and detect superheavy elements using the 88" cyclotron and the Berkeley Gas-filled Separator. In addition, to eliminate ambiguities, we can identify the mass number of the superheavy elements using the FIONA setup. However, in order to study properties such as their mass, the superheavy ions have to first be stopped in a gas catcher and then trapped in a Paul trap in order to have an acceptable emittance. After cooling and bunching, they can only be accelerated to an energy of a few keV which is not enough to penetrate the dead layer of the Si wafer at the end of FIONA.

To overcome this limitation, we have developed a novel Time-of-Flight detector for use in mass identification experiments with FIONA and future high precision mass measurement experiments with the MR-ToF in Berkeley Lab. This detector combines a double-sided-silicon-strip detector (DSSD) and a micro-channel plate detector (MCP). The former provides the position sensitivity that corresponds to an A/q in FIONA as well as the decay information. The latter is used to detect secondary electrons emitted upon impact on the DSSD which provide the implantation time. This new detector significantly reduces the background in FIONA, allows for lifetime measurements and preserves the position resolution. The design, first results and current and future applications will be discussed.

Speaker: Marilena Lykiardopoulou (Lawrence Berkeley National Lab)

31 KISS1.5 for multi-nucleon transfer experiment, ion optics of a mass range separator¶

Speaker: Yutaka Watanabe (KEK WNSC)

32 Development and application of a dispersion-matched ion-optical mode of the SRC and BigRIPS system for high-resolution missing-mass spectroscopy experiments with primary beams¶

The high-intensity beams available at RIBF provide new opportunities for precision missing-mass spectroscopy with reactions using primary ion beams. One of the essential techniques to achieve excellent missing-mass resolution is the realization of dispersion-matched ion optics, which minimizes the effects of the momentum spread of the incident beams. We have developed a dispersion-matched ion-optical mode for the entire system —from the SRC cyclotron and beam transport line, reaction in the target, to the BigRIPS spectrometer— and established a practical tuning procedure. This mode was successfully applied in two experiments conducted in 2021: one for spectroscopy of deeply-bound pionic atoms and the other for the search for double Gamow-Teller giant resonances. In this contribution, we summarize the design, development, and operational performance of this newly established dispersion-matched ion-optical mode.

Speaker: Yoshiki Tanaka (RIKEN)

33 What's special about the ARIEL HRS?¶

High resolution separators have a reputation as being unstable and difficult to tune. The ARIEL HRS has been designed to overcome these difficult characteristics. To do this, it has two unique features. (1) The matching system into and out of the HRS acts as both a matcher and a dispersion-magnifier. (2) The aberration correction is not performed using a conventional multipole. Instead, the correction element is a flat arrangement of electrodes that are programmed according to the correction function rather than a multipole-at-a-time approach.

Speaker: Richard Baartman (TRIUMF)

34 Recent advances of the S3-Low Energy Branch¶

The SPIRAL2 facility of GANIL will significantly extend the capability to study short-lived nuclei by producing beams of rare isotopes at unprecedented intensities. The SPIRAL2-LINAC coupled with the Super Separator Spectrometer (S${}^3$) recoil separator will facilitate the production of neutron-deficient nuclei close to the proton dripline as well as super heavy nuclei via fusion-evaporation reactions, with an efficient separation from the intense background contamination [1]. At the focal plane of S${}^3$, the Low Energy Branch (S${}^3$-LEB) will enable low-energy nuclear physics experiments by thermalising and neutralising the nuclei in a gas cell before extraction in a supersonic gas jet. In the jet, resonant laser ionisation can serve as both a selective ion source and a method of spectroscopy.

Resonant laser ionisation spectroscopy in the low density and low temperature environment of the supersonic jet will boost the spectral resolution by an order of magnitude, while maintaining the typical efficiency of in-source laser spectroscopy [2]. The technique allows the precise investigation of isotope shifts and hyperfine structures at the extremes of the nuclear chart. This will give access to ground-state properties such as spins, charge radii and electromagnetic moments in a nuclear-model-independent framework. Combined with the PILGRIM MR-TOF and the SEASON decay station, mass and decay measurements will also be performed. The S${}^3$-LEB setup has been commissioned offline in a dedicated laboratory [3, 4], and is now installed at the focal plane of S${}^3$, in preparation for online commissioning.

We present the latest results of the offline commissioning of the setup, including a detailed characterisation of the gas jet combined with series of mass measurements using PILGRIM using, e.g., erbium isotopes. The preparation for online experiments at S${}^3$ and the first scientific objectives with short-lived nuclei in the coming years will be shown. In addition, we will present the results and perspectives of ongoing related projects, such as FRIENDS${}^3$, which aims at improving the extraction speed and neutralisation of the gas cell, and IDEAS${}^3$, a tape-based identification station under development.

[1] F. Déchery et al., Nucl. Instrum. Meth. B 376, 125-130 (2016)
[2] R. Ferrer et al., Nat. Comm. 8, 14520 (2017)
[3] J. Romans, et al., Atoms 10(1), 21 (2022)
[4] A. Ajayakumar, et al., Nucl. Instrum. Meth. B 539, 102 (2023)

Speaker: Sarina Geldhof (GANIL)

Poster Session¶

Wednesday, 22 October ¶

Isotope Production, Target and Ion Sources II¶

35 Producing short-lived isotopes by fusion evaporation reactions in the TULIP TISS at GANIL¶

SPIRAL1 (Système de Production d’Ions Radioactifs Accélérés en Ligne phase 1) is an ISOL system installed at GANIL (Grand Accélérateur National d’Ions Lourds) at CAEN/France. Since 2001, it uses a large variety of primary beams, from C to U, at energies up to 95 MeV/u to produce low energy or post-accelerated Radioactive Ion Beams (RIB). The possibilities of primary beam and target coupling allow SPIRAL1 [1] to use a large variety of nuclear reactions, which eases access to regions of the nuclide chart often difficult to explore with ISOL installations.
Within this framework, the TULIP project [2] aims to produce original RIBs in the very exotic neutron-deficient region of the nuclide chart. The approach consists of favouring the atom-to-ion transformation efficiency for short-lived isotopes rather than the in-target production rate. The Target Ion Source System (TISS) design was guided by the improvement of the efficiency of each process involved, i.e. in-target production, diffusion of atoms out of the stopping material, effusion and ionisation.
A first TISS prototype was designed to produce ions of neutron deficient isotopes of Rb. Once the proof of principle shown [3,4], the TISS was coupled to a FEBIAD [5] ion source to reach the final aim of the TULIP project, namely the production of metallic ions near 100Sn.
The status of this project and the first results will be presented.

Speaker: Pascal JARDIN (CNRS/IN2P3/GANIL)

36 Ion source development for TATTOOS: the new large-scale radionuclide production infrastructure at the Paul Scherrer Institute¶

TATTOOS (Targeted Alpha Tumor Therapy and Other Oncological Solutions) offers the potential to produce radionuclidically pure radioisotopes towards radiopharmaceutical applications, revolutionizing cancer diagnosis and treatment. The facility plans to utilize a portion (100 μA) of the high-intensity (~2.4 mA), high-energy (590 MeV) proton beam from the ring cyclotron at Paul Scherrer Institute's High Intensity Proton Accelerator (HIPA) facility, combined with dedicated high-power spallation targets, to produce radionuclides. The proton beam impinging on the joule-heated target results in a spallation reaction. Nonselective surface ionization or selective laser resonance ionization occurs inside an ionizer tube directly attached to the target. These ions are extracted by high voltage fields and guided towards the online mass separation using a dedicated dipole magnet.
The ion optical extraction geometry has a significant impact on beam parameters and, consequently, on ion beam transport efficiency as well as on the achievable resolving power of the mass separation. The analysis of ion trajectories defines the beam quality that can be translated into the emittance and the energy spread of the beam. Studies on TATTOOS’s proposed ion beam extraction were performed, simulating the effect of ionization via either surface or laser or a combination of both being investigated. Optimum ionizer and ion extraction designs, based on these simulations, will be presented. Furthermore, the envisaged laser infrastructure as well as the beam transport with respect to the layout of the future TATTOOS building and the proposed arrangement of target and ion beamline will be presented.

Speaker: Maryam Mostamand

37 ARIEL: New infrastructure, new opportunities for target and ion source development¶

With multiple planned online target stations and offline test stands, TRIUMF is establishing a unique facility for the production of radioactive ion beams (RIBs). This multi-station configuration, centered around the ARIEL project, creates unique opportunities for systematic R&D on ISOL targets, ion sources, and associated technologies. The magnitude of the project presents commissioning challenges, while also offering a chance to characterize the system from the outset, thus establishing a baseline for near and future developments such as more complex target and ion source combinations. This contribution presents an overview of the R&D strategy for ISOL target and ion sources in TRIUMF’s multi-RIB era.

Speaker: Fernando Alejandro Maldonado Millan (TRIUMF)

38 Engineering of small grain size and porous Th-based targets for ISOL@MYRRHA¶

Isotope Separation Online (ISOL) facilities generate purified radioactive isotope beams for research in fundamental nuclear and atomic physics, condensed-matter, biology and medical applications. As part of the first phase of the MYRRHA program at SCK CEN, a new ISOL facility is being developed, ISOL@MYRRHA, featuring a high-power 100-MeV proton beam with currents up to 500 μA. This will enable the production of relevant isotopes for medical research, including 225Ac, which is highly targeted for cancer research. This work focuses on the development of thorium-based targets, initially on ThO2 engineered with pore formers and later on ThCx, optimized for efficient isotope release at extreme temperatures  2000 °C. Key material properties for refractory-isotope release include micrometer-scaled open porosity (>30%) and small grain size (<10 µm) stable at the above-mentioned elevated temperatures. Highly-porous ThO2 targets were produced from ThO₂ powder synthesized via oxalate precipitation from Th(NO3)4. The resulting powder consisted of platelets with varying micrometric dimensions. ThO2 powder was mixed with pore formers in different volume ratios, then pelletized, thermally treated in air, and sintered in a reducing atmosphere. The process parameters were adjusted to achieve the desired density and grain size using pore formers. The thermal stability of ThO2 was tested for 24 h above 2000 °C in vacuum, at CERN-ISOLDE. Remarkably, small grain sizes and porosity survived these extreme conditions, demonstrating the material’s robustness as an ISOL target. In this contribution, we present the structure of several engineered ThO2 prototypes and their evolution after exposure to temperatures above 2000 °C.

Speaker: Lisa Gubbels (SCK CEN)

Health Break¶

Ion guide, gas catchers, & beam manipulation techniques¶

39 Overview of ISOL facilities and production techniques¶

Isotope Separator On-Line (ISOL) facilities are central to the production of high-purity radioactive ion beams (RIBs) for a variety of research applications. Emerging facilities are increasingly focused on high-power operation, where radioisotope yields are expected to scale directly with the primary beam power. However, significant engineering challenges must be addressed to ensure that high-power Target and Ion Source Systems (TISS) are as efficient as those operating in the low-power regime. Moreover, RIB yields at ISOL facilities typically degrade over time due to extreme operating conditions—such as targets and ion sources functioning at temperatures exceeding 2000 °C—a problem expected to intensify in high-power TISS scenarios.

TISS development typically aims to maximize the efficiency of isotope extraction and ionization, enabling access to shorter-lived isotopes and even new elements. In parallel, the growing interest in using the ISOL technique to produce research-scale quantities of novel medical isotopes introduces new challenges. For example, high-throughput ion sources with high ionization efficiencies are increasingly in demand. High-power targets, in particular, face issues such as cold spots that can trap isotopes of interest, or high mechanical stresses in target disks caused by localized beam power deposition. Offline extraction, from previously irradiated targets or even external sources of radioisotopes has also become of interest, introducing new challenges into the ISOL systems. Other TISS related components such as converter targets (e.g. proton to neutron, electron to gamma), in-situ purifying transfer lines or reactive gas leaks or dispenser ovens for molecular beam formation can also be part of the TISS, opening up new beams for the applications mentioned, but making them even more complicated which can affect the TISS reliability.

Research on targets and ion sources systems is often conducted as small, isolated projects driven by the scientific interests of the user community. These technological advancements can lead to significant increases in RIB yields and enable access to new isotopes and elements at the extremes of the nuclear chart. This lecture aims to provide a comprehensive overview of the present and future ISOL facilities and their status, with a focused discussion on their recent technological developments in target and ion source systems (TISS).

Speaker: João Pedro Ramos (SCK CEN - Belgian Nuclear Research Centre)

40 FRS Gas Catcher¶

Speaker: Gabriella Kripko-Koncz (University of Edinburgh)

41 Neutron-rich beams from gas catchers: the nuCARIBU and N=126 factory facilities¶

The availability of heavy neutron-rich beams is critical to our understanding of the astrophysical r-process responsible for the formation of most of the heavy elements. The CARIBU facility at ATLAS has been providing such beams for over a decade through harnessing the fission products from the spontaneous fission of 252Cf in a large RF gas catcher, mass separating them and delivering them to experiments either at low-energy or reaccelerated to Coulomb barrier energy. In order to increase the intensity of the fission fragment beams and provide access to the heavier neutron-rich isotopes responsible for the formation of the last r-process abundance peak, two new facilities have been constructed at ATLAS: nuCARIBU and the N=126 factory. Both utilize a similar approach to that demonstrated at CARIBU, i.e. use of a large high-intensity RF gas catcher optimized to efficiently thermalize and extract the reaction products followed by universal and fast mass separation of increasing resolution to isolate the isotopes of interest. nuCARIBU replaces the 252Cf fission source of CARIBU by a neutron-generator that produces neutron-induced fission in a thin actinide foil located inside the gas catcher. The N=126 factory utilizes multi-nucleon transfer reactions to produce very neutron-rich isotopes in regions poorly populated by fission and standard reaction mechanisms and thermalizes them in a large RF gas catcher optimized to stop fast reaction recoils produced in the very large cone angle characteristic of this reaction mechanism. Both facilities are based on the large high-intensity RF gas catcher developed for CARIBU that has been adapted to the specific needs of these applications.
The two facilities will be introduced, their capabilities presented, and a particular emphasis will be given to the gas catcher development and modifications that were needed for these applications.

Speaker: Guy Savard (Argonne National Laboratory / University of Chicago)

42 The RAdium-Fluride Ion Catcher Instrument - A path towards offline eEDM experiments with RaF¶

Molecules have proven to be powerful laboratories to explore unknown aspects of the fundamental forces of nature and to search for physics beyond the standard model. By choosing molecules containing radioactive isotopes with different spins and deformation one can explore aspects of the fundamental forces even further and reach unparalleled enhancement of symmetry-violating properties. Among many potential candidate molecules, Radium-monofluoride (RaF) has emerged as a potent candidate. However, the production of radioactive molecules in general has proven to be challenging and availability of molecular radioactive ion beams has been identified as a bottleneck for future research. Particularly as suitable radioactive partner species have to be produced at large scale online radioactive beam facilities; preventing experiments at local universities laboratories.

In this contribution we introduce the RAdium-Fluride Ion Catcher Instrument (RAFICI) scheme using gas filled stopping-cell and ion trapping technology, and discuss its application as a universal and fast source of short-lived radioactive isotopes for systematic studies of molecules of elements between Z=82 and Z=98 without the need for local nuclear reactors or accelerators.

The scheme was successfully tested at the FRS Ion Catcher at GSI and first offline production of RaF could be shown via gas phase reactions of recoil ions with SF6 inside a versatile RFQ beam line at the FRS Ion Catcher, where Ra-224 ions were harvested following the decay of a Th-228 sample within a gas filled stopping cell. We can show, that the reaction Ra^+2 + SF6 --> RaF^+ + SF5^+ reaches an almost unity conversion efficiency and, with chemical reaction times on the millisecond time scale. This shows that in-trap ion-gas phase reactions are a promising pathway for offline experiments based around RaF. At the FRS Ion Catcher this program can, in principle, also be expanded to all isotopes produced in in-flight fragmentation of U-238, due to the online beam production capabilities at the FRS. A dedicated RAFICI device, currently under commissioning at the University of Edinburgh, enables experiments with radioactive molecules decoupled from online radioactive beam facilities. The scheme can straightforward be expanded for the production of may actinides and 6p to 5f elements and opens research pathways across multiple fields.

Speaker: Moritz Pascal Reiter (University of Edinburgh)

43 Progress on the new Universal High-Density Gas Stopping Cell (UniCell) for Supherheavy Element Chemistry Studies¶

Experimental investigations targeting chemical properties of superheavy elements (SHE) have reached element 115 (Mc) [1]. Chemistry experiments of the heaviest elements are carried out by thermalizing their energetic recoils produced in fusion-evaporation reactions within a gas-filled volume and transporting these solely by gas-flow to a detection setup. The transport process typically requires at least about 0.5 seconds. The next heavier known elements 116 (Lv) to 118 (Og) can be produced at rates of few single atoms per week, but only isotopes with half-lives well below 100 ms are known to date. To extend chemical studies to these elements, a highly-efficient stopping cell with superimposed electrical fields to significantly reduce the transfer time from the separator to the chemistry setup is required. First exploratory experiments with an existing stopping cell coupled to a chemistry-detection setup have been successfully conducted and demonstrated the feasibility of the approach [2,3]. In recent stopping cells, the extraction efficiency is typically in the order of 30 – 75% and the extraction time in the order of tens of ms [4]. To enable studies of the next-heavier chemically unexplored element 116 (Lv), high efficiency for fast-extraction times is highly desirable. Following a concept by Varentsov and Yakushev [5], the atmospheric-pressure stopping cell UniCell has been designed and is currently under construction. Its main component is a ceramic ion funnel with ca. 180 electrodes and 100 µm electrode spacing. In this contribution, we report on simulations studying the stopping cell in detail and present the status of its construction, capabilities and its future prospects.

[1] A. Yakushev et al., Front. Chem. 12 (2024) 1474820
[2] S. Götz et al, Nuclear Instruments and Methods in Physics Research Section B 507 (2024) 27
[3] G. Tiebel et al, The ion-funnel-to-IVAC system, Annual Report 2023, Laboratory of Radiochemistry, p. 5
[4] C. Droese et al, Nuclear Instruments and Methods in Physics Research B 338 (2014) 126
[5] V. Varentsov and A. Yakushev, Nuclear Instruments and Methods in Physics Research B 940 (2019) 206

Speaker: Jochen Ballof (GSI Helmholtzzentrum für Schwerionenforschung)

Lunch¶

Free afternoon¶

Thursday, 23 October ¶

Low-energy & in-flight separators¶

44 High-power beam dumps¶

Speaker: Yasuhiro Togano (RIKEN Nishina Center for Accelerator-Based Science)

45 Radioactive ion beams at the Nuclear Science Laboratory¶

For over 30 years, the TwinSol radioactive ion beam facility at Notre Dame’s Nuclear Science Laboratory has provided in-flight radioactive ion beams (RIB) to a variety of experiments probing nuclear structure, astrophysics and fundamental symmetries. These relatively low-mass, high-rate beams have enabled a swath of science, including high-precision beta-decay half-life measurements, probes of electromagnetic observables in the lightest nuclei, and recoiling detection measurements of astrophysically-relevant cross-sections. Currently, TwinSol beams can either be delivered to the Superallowed Transition Beta-Neutrino Decay Ion Coincidence Trap (St. Benedict) facility for precision beta decay measurement, or through a newly installed third solenoid for improved beam purity and RIB mass range for a variety of experiments. The first RIB developments for these beamlines, recent technical developments, as well as the current and future scientific program at the new TriSol facility will be presented.

Speaker: Sam Porter (University of Notre Dame)

46 NEXT - A new setup to study Neutron-rich Exotic, heavy, nuclei produced in multinucleon Transfer reactions¶

The NEXT setup [1] has been designed and built to study Neutron-rich, heavy, EXotic nuclei produced in multinucleon Transfer reactions. NEXT is a new experiment at the PARTREC facility in Groningen which has been recently installed in a dedicated beamline at the AGOR cyclotron [2]. The AGOR cyclotron at PARTREC is capable to deliver highly intense heavy ion beam at energies well suited for multinucleon transfer reactions at and above the Coulomb barrier.
NEXT consists of a solenoid pre-separator. Within the field of a 3-tesla strong, superconducting solenoid magnet heavy transfer products are separated from their light counterparts [3] and focused towards a gas-catcher [4]. The ions are extracted through a radiofrequency carpet into a novel ring-ion guide and buncher [5] from where they are injected into a MultiReflection Time-of-Flight Mass Spectrometer [6] for precision mass measurement and sample preparation for background free mass spectrometry. Thus, even very long-lived, heavy transfer products can be identified and studied with NEXT.
Our contribution will provide an overview of the NEXT setup and a report on the first beam on target experiments performed in summer 2025.

[1] J. Even, X. Chen, A. Soylu, P. Fischer, A. Karpov, V. Saiko, J. Saren, M. Schlaich, T. Schlathölter, L. Schweikhard, J. Uusitalo, and F. Wienholtz, The NEXT Project: Towards Production and Investigation of Neutron-Rich Heavy Nuclides, Atoms 10, 59 (2022).
[2] B. N. Jones, S. Brandenburg, and M. J. van Goethem, AGOR Status Report, CYC 2019 - Proc. 22nd Int. Conf. Cyclotrons Their Appl. 257 (2020).
[3] A. Soylu, X. Chen, J. Even, A. Karpov, V. Saiko, J. Sarén, and J. Uusitalo, Ion-Optical Simulations for the NEXT Solenoid Separator, Nucl. Instruments Methods Phys. Res. Sect. A Accel. Spectrometers, Detect. Assoc. Equip. 1067, 169674 (2024).
[4] A. Mollaebrahimi, B. Anđelić, J. Even, M. Block, M. Eibach, F. Giacoppo, N. Kalantar-Nayestanaki, O. Kaleja, H. R. Kremers, M. Laatiaoui, and S. Raeder, A Setup to Develop Novel Chemical Isobaric SEparation (CISE), Nucl. Instruments Methods Phys. Res. Sect. B Beam Interact. with Mater. Atoms 463, 508 (2020).
[5] X. Chen, J. Even, P. Fischer, M. Schlaich, T. Schlathölter, L. Schweikhard, and A. Soylu, Stacked-Ring Ion Guide for Cooling and Bunching Rare Isotopes, Int. J. Mass Spectrom. 477, 116856 (2022).
[6] M. Schlaich, J. Fischer, P. Fischer, C. Klink, A. Obertelli, A. Schmidt, L. Schweikhard, and F. Wienholtz, A Multi-Reflection Time-of-Flight Mass Spectrometer for the Offline Ion Source of the PUMA Experiment, Int. J. Mass Spectrom. 495, 117166 (2024).

Speaker: Julia Even (University of Groningen)

47 Current Status of Laser Ion Source Development at RAON¶

The Resonance Ionization Laser Ion Source (RILIS) has become the most-used ion source type in the ISOL (Isotope Separator On-Line) facilities worldwide due to its element selectivity and high ionization efficiency. The hot-cavity type RILIS developed at RAON is based on resonant excitation of atomic transitions by the frequency tuned laser beams which are overlapped temporally and spatially and transported to the 3 mm aperture of the hot-cavity The RILIS laser system consists of 4 Ti:sapphire lasers (High Rep. Ti:Sapphire Laser, Radiant Dyes Laser Accessories GmbH) pumped by a Nd:YAG laser (LDP series, Lee Laser Inc.) at 10 kHz repetition rate. An additional Nd:YAG laser (Talon HE GR1000, Spectra-Physics Inc.) of 10 W with 10 kHz is also fitted up for off-resonance ionization scheme. For the laser ionization scheme study, the RAON RILIS has been already tested with stable Sn isotopes in the off-line test facility, demonstrating the improved ionization efficiency [1,2].
In this presentation, we will report on both stable and RI beam studies of Mg isotopes, which are currently underway for the development of the resonance ionization laser ion source at the ISOL facility of IRIS.

[1] S. J. Park et al., Nuclear Inst. And Methods in Physics Research B 414, 79 (2018)
[2] S. J. Park et al., Journal of the Korean Physical Society, DOI : 10.1007/s40042-024-01208-2 (2024)

Speaker: Ha-Na Kim (Institute for Rare Isotope Science (IRIS) / Institute for Basic Science (IBS))

Health Break¶

Ion traps & laser techniques II¶

48 MR-ToF Devices: New Applications and Developments¶

Over the past 15 years, Multi-Reflection Time-of-Flight (MR-ToF) devices have established themselves as indispensable instruments for mass measurements and mass separation of short-lived radionuclides at radioactive ion beam (RIB) facilities. Within the MIRACLS collaboration at ISOLDE/CERN, we have expanded the use of MR-ToF devices, adapting them for highly sensitive collinear laser spectroscopy (CLS). By storing ions between the two electrostatic mirrors of an MR-ToF device, the same ion bunch is probed by a laser thousands of times compared to a single passage in traditional CLS [1,2]. The resulting increase in experimental sensitivity allowed us to access nuclear charge radii of neutron-rich magnesium isotopes, which were out of reach for conventional CLS due to their very low production yields. These measurements offer new insights into the island of inversion and provide stringent benchmarks for nuclear theory. Additionally, we measured the electron affinity of 35Cl with comparable precision to the literature value [3] despite utilizing five orders of magnitude fewer ions. This opens the door to future electron affinity studies of superheavy elements as well as across isotopic chains, which will challenge the predictive power of fully relativistic many-body quantum theories.
The development of the high-voltage MR-ToF device for MIRACLS, capable of storing ions at beam energies exceeding 10 keV as required to preserve the high resolution of conventional CLS, is also of great interest for achieving highly selective and high-flux MR-ToF mass separation. Simulations show that the ion throughput can be enhanced by more than 2 orders of magnitude when increasing the kinetic energy of the stored ions to 30 keV and when improving the MR-ToF design [4,5]. MIRACLS high-voltage MR-ToF device is hence foreseen to be repurposed as a mass separator at ISOLDE, while a dedicated 30 keV MR-ToF device is in development at FRIB to provide isobarically and isomerically purified beams at high rates to subsequent experiments.
This contribution presents the highly sensitive laser spectroscopic measurements at MIRACLS and outlines the design, development status, and the planned first science cases of FRIB’s highly selective and high-flux MR-ToF mass separator.
[1] S.Sels et al., NIMB 463, 310-314 (2020)
[2] F.M.Maier et al., NIMA 1048, 167927 (2023)
[3] U.Berzinsh et al., Phys. Rev. A 51, 231 (1995)
[4] F.M.Maier et al., NIMA 1056, 168545 (2023)
[5] F.M.Maier et al., NIMA 1075, 170365 (2025)

Speaker: Franziska Maier (FRIB)

49 Precision Spectroscopy of Heavy and Superheavy Elements with AETHER¶

Superheavy elements edge the limits of matter's existence. Their extreme proton content presents opportunities to explore fundamental questions across chemistry, atomic physics, and nuclear physics. For instance, we ponder how enhanced relativistic effects impact atomic structure and chemical properties, or how nuclear shell effects evolve under such extreme conditions. Yet, the journey to uncover these answers is fraught with challenges. Typically, only a handful samples of such elements are produced each day or even less. These conditions drives continuous innovation in instrumentation and development of new methodologies, especially pushing for higher experimental sensitivity.

In my presentation, I will show the novel avenues under construction at Barkeley Lab to probe heavy and superheavy elements though modern precision spectroscopy techniques. The new project, Advanced Electrostatic Trap for Heavy Element Research (AETHER), will initially focus on measuring nuclear binding energies with precision mass spectrometry, aiming to address nuclear structure questions at the upper end of the table of nuclides. Looking ahead, we plan to capitalize on the remarkable sensitivity recently demonstrated by the Multi Ion Reflection Apparatus for Collinear Laser Spectroscopy (MIRACLS) methodology to achieve groundbreaking measurements of electron affinities for rare elements — an essential atomic property that remains unknown across approximately one-third of the periodic table.

Speaker: Dr Erich Leistenschneider (Lawrence Berkeley National Laboratory)

50 The CRIS technique and its latest advances: towards more exotic isotopes and beyond nuclear structure studies¶

In the last decade, the collinear resonance ionization spectroscopy (CRIS) technique [1,2] has proven to be a powerful tool for investigating atomic and nuclear properties of exotic nuclei across the nuclear chart [3,4,5]. CRIS stands out through its combination of conventional collinear resonance spectroscopy with resonance ionization, enabling the extraction of high-resolution data on nuclear moments, mean-square charge radii, and the unambiguous determination of nuclear spins, even for isotopes produced at rates as low as a few tens of ions per second [6]. More recently, the CRIS experiment has also pioneered studies on short-lived radioactive molecules, in particular RaF, opening a new path for future beyond standard-model physics searches at low energies [7].

With the latest developments on the CRIS experiment, the versatility of the technique has been further enhanced. The addition of a new field ionization unit and widely tuneable laser systems gives opportunities for an improved sensitivity of the technique. These upgrades additionally support the efficient identification of experimentally yet unknown electronic levels for new atomic physics studies, and for laying the foundation for future high-precision measurements. CRIS has recently also enabled the study of negative ions, most notably RaF${}^{-}$ anions, which were successfully produced for the first time and investigated via laser photodetachment studies. These methodological advances provide essential groundwork for a potential implementation of a cooling and trapping scheme for this radioactive molecule.

In this contributions, recent highlights and technical upgrades of the CRIS experiment are presented and an outlook on further developments for on-line experiments at ISOLDE at the extremes of the nuclear landscape are given.

[1] K.T. Flanagan et al. Phys. Rev. Lett. 111, 212501 (2013).
[2] R.P. de Groote et al. Phys. Rev. Lett. 115, 132501 (2015).
[3] K.M. Lynch et al. Phys. Rev. X 4, 011055 (2014).
[4] A. Koszorus. et al. Nat. Phys. 17, 439–443 (2021).
[5] A.R. Vernon et al. Nature 607, 260–265 (2022).
[6] R.P. de Groote et al. Nat. Phys. 16, 620–624 (2020).
[7] R. Garcia Ruiz et al. Nature 581, 396–400 (2020).

Speaker: Jessica Warbinek (CERN)

51 Simultaneous mass spectrometry and in-source laser spectroscopy of exotic nuclides from ISOLDE¶

The ISOLTRAP mass spectrometry program at ISOLDE has pioneering many developments over the past decades, the most recent being the combination of precision time-of-flight mass spectrometry and in-source laser-ionization scanning to obtain the hyperfine structure of the isotope of interest.

First developed using sensitive alpha spectroscopy, the successful in-source spectroscopy technique was considerably extended by counting ions instead of radioactivity. Moreover, the high-resolution offered by ion traps enabled a dramatic gain in sensitivity not possible with dipole mass separators.

This contribution will recall the development of the in-source MS technique with some of the highlights before presenting new mass-spectrometry results for neutron-rich mercury (212Hg) and neutron-deficient cadmium (97Cd), both of which are near the intersections of major shell closures.

Speaker: David Lunney (CNRS)

Lunch¶

Machine Learning & AI¶

52 Development of automatic beam tuning system for high intensity heavy ion beams at RIBF¶

In general, accelerator facilities are controlled by a huge number of parameters. The RIKEN RI Beam Factory (RIBF), a heavy-ion accelerator complex consisting of several cyclotrons and Linacs, is controlled or influenced by more than 600 parameters, including environmental factors. To optimize these parameters more efficiently and accurately, we are attempting to implement Bayesian optimization (BO). Given the importance of space charge effects and beam loading, it is desirable to adjust parameters at high beam intensity, making it crucial to develop an optimization system capable of handling high-intensity heavy ion beams.
We have been working on developing indices suitable for high-intensity beams and exploring methods for optimization while maintaining operational safety. So far we developed a technique that enables the simultaneous measurement of beam transmission and spot shape on the target by tracking charge-converted particles after passing through the target. Additionally, we are investigating the use of line BO with a safety function to ensure safe beam optimization. Currently, we are preparing for simulations and tests using beam line.

Speaker: Takahiro Nishi (RIKEN Nishina Center)

53 Model coupled beam tuning and Bayesian optimization of rare isotope beam transport to the DRAGON experiment at TRIUMF¶

The Isotope Separator and ACcelerator (ISAC) facility at TRIUMF supplies both stable and rare isotope beams for a variety of nuclear astrophysics experiments. One of these, the Detector of Recoils And Gammas Of Nuclear reactions (DRAGON), investigates reaction rates of astrophysical processes via radiative capture measurements. Currently, rare isotope beams delivered to DRAGON are manually tuned by operators—a process that is both time consuming and difficult to train for, especially given the boundary condition of high demand for beam time. This work presents a semi-automated approach to optimize beam transport through the ISAC-I linac and towards DRAGON. The method decouples the tuning of quadrupole lenses and corrective steerers. Quadrupoles are adjusted using Model Coupled Accelerator Tuning (MCAT) to match a design tune, while Bayesian Optimization for Ion Steering (BOIS) is used to do the beam orbit correction. BOIS treats steering as a black-box optimization problem, evaluating functional values only through direct measurement to maximize beam transmission. By combining MCAT and BOIS, this method offers a more efficient and physics grounded tuning process for the facility.

Speaker: Omar Hassan (TRIUMF, University of Victoria)

54 Bayesian optimization applied to simultaneous tuning of the ion source and transport beamline of an Isotope Separator On-line system.¶

The Isotope Separation On-Line (ISOL) technique has enabled advances in many fields spanning in nuclear, atomic, molecular, solid-state and medical physics by producing radioisotopes at facilities like CERN ISOLDE and the emerging ISOL@MYRRHA. Tuning these facilities is a complex task that requires manual intervention by experienced operators, a process that is often time-consuming due to the many parameters involved. In recent years, optimization algorithms have emerged as effective tools to support this tuning process. Among the key tuning tasks, the adjustment of ion source parameters plays a crucial role in maximizing the yield of the extracted ion beam. Since modifications to the ion source parameters can affect the beam energy and emittance, automatic re-tuning of the transport beamline parameters is required to ensure that beam intensity and shape performance criteria are satisfied. In this study, a nested optimization approach is proposed, utilizing Gaussian processes and Bayesian optimization to maximize the beam intensity of a selected isotope or molecule. Developed for ISOL@MYRRHA at SCK CEN and implemented in its ISOL offline system, the method was experimentally validated at CERN’s ISOLDE Offline 2 facility by maximizing the intensity of various isotopes across different operation parameters.

Speaker: Santiago Ramos Garces (Belgian Nuclear Research Centre (SCK CEN))

55 The new MRTOF mass spectrometer at HIAF facility¶

A new state-of-the-art multi-reflection time-of-flight mass spectrometer, referred to as HKU-MRTOF, has been constructed in the HKU-KEK collaboration. It aims to operate for nuclear mass measurements of multinucleon transfer (MNT) products at the HIAF facility, through coupling to a cryogenic gas cell. It is part of a low-energy station for making full use of the low-energy heavy-ion beams provided by the Linac. Detailed information about the MRTOF setup and results of the offline test will be reported here.

Speaker: Chaoyi FU (The university of Hong Kong)

56 Radioactive Beam Transport Automation via Bayesian Optimization¶

Radioactive ion beams enable researchers to probe rare and unstable atomic nuclei, providing critical insights into the internal structures of exotic nuclei and the processes of stellar nucleosynthesis. However, the extraction and transport of these beams have traditionally depended on expert-driven tuning methods, where hundreds of parameters must be manually optimized—a time-consuming endeavor. At the ATLAS facility at Argonne National Laboratory, we have implemented a novel system that leverages Bayesian Optimization (BO) to streamline the radioactive beam transport process. In this presentation, I will discuss how our BO-based methodology has successfully been applied during live beam tuning sessions for multiple beam line sections and using the beta-decay activity as the key observable to maximize. Additionally, I will outline our strategies for expanding this system within our facility, highlighting the potential for broader impact in the field.

This work was supported by the Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357, and DE-FOA-0002875 funds. This research used resources of ANL's ATLAS facility, which is a DOE Office of Science User Facility.

Speaker: Daniel Santiago-Gonzalez (Argonne National Laboratory)

Health Break¶

Applications of RIB¶

57 Developments for Standard Model tests with radioactive molecules¶

Speaker: RONALD GARCIA RUIZ (MIT)

58 FIRST IMAGE-GUIDED TREATMENT OF A MOUSE TUMOR WITH RADIOACTIVE ION BEAMS¶

Heavy ion particle therapy is a rapidly growing and potentially the most effective and precise radiotherapy technique. However, the sharp dose gradients in the distal ends make it extremely sensitive to range uncertainties. In clinical practice, wide margins extending into normal tissue are commonly used to ensure tumor coverage, thereby jeopardizing the benefits of the sharp Bragg peak. Online range verification techniques could potentially help to overcome this limitation.
PET (positron emission tomography) is one of the most established methods to verify the beam range. However, for ${}^{12}$C-ion therapy, the low signal-to-noise ratio, the physical shift in the β${}^{+}$ activity and dose peak, and the long required acquisition times limit the PET-based range verification accuracy to approximately 2–5 mm.
The direct use of β${}^{+}$ radioactive ion beams (RIB) for both treatment and imaging could help overcome these limitations.

In this context, the BARB (Biomedical Applications of Radioactive Ion Beams) project was initiated at GSI, aiming to assess the efficacy of ${}^{11}$C-ion combined with real-time PET imaging, for precise tumor control and toxicity minimization in a preclinical model.

Besides introducing the potential of RIB in clinical applications, the results from the vast experimental campaign, including research ranging from basic nuclear physics and PET detectors developments to animal treatments, will be here presented.

Speaker: Daria Boscolo (GSI)

59 Development of Terbium Fluoride Beams for Medical Applications¶

A quartet of short-lived terbium isotopes, ${}^{149}$Tb, ${}^{152}$Tb, ${}^{155}$Tb and ${}^{161}$Tb, has been identified to have complementary decay characteristics with a unique potential to cover all modalities of nuclear medicine in both therapy and diagnostics [1]. Of particular interest is the alpha-emitter, ${}^{149}$Tb, which could fill the gap in targeted alpha therapy. However, the production of these isotopes, aside from reactor-produced ${}^{161}$Tb, remains challenging, with current methods unable to meet the demands of sustained preclinical research [2].

The Isotope Separation On-Line (ISOL) technique is currently the only method capable of producing enough activity of ${}^{149}$Tb, ${}^{152}$Tb and ${}^{155}$Tb with high enough radioisotopic purity for development of terbium-based radiopharmaceuticals [2]. However, because terbium is non-volatile, it is notoriously difficult to extract as an ion beam with sufficient intensity and purity. As a result, terbium isotopes are currently produced indirectly through the extraction of laser-ionized dysprosium [1]. The development of isotope extraction via molecular sidebands offers a promising pathway to access non-volatile elements, such as terbium, that are otherwise difficult to extract directly from the target [3–5].

In this work, we report on systematic studies of terbium fluoride beams performed at CERN-ISOLDE, using a tantalum target coupled to a hot plasma ion source with the injection of reactive tetrafluoro-methane (CF${}_4$) gas. The ion beam composition was investigated as a function of target, ion source, and gas injection conditions to optimise the terbium fluoride beam delivery. To gain insight into the underlying physics processes, the extended isotopic chain between masses A=144-168 was explored, as well as other lanthanides in this mass range. Beam composition identification and yield measurements were primarily conducted using the ISOLTRAP MR-ToF MS [6], complemented by offline gamma and alpha spectrometry. Moreover, these studies provided valuable information on the behaviour of other lanthanide beams.

The future of large-scale terbium isotope production lies in the optimization of extraction techniques which can be applied at emerging facilities such as ISOL@MYRRHA and TATTOOS@PSI. The presented work is a part of ongoing efforts to optimise production of terbium radionuclides for clinical and preclinical applications.

[1] C. Müller et al. “A unique matched quadruplet of terbium radioisotopes for PET and SPECT and for α-and β-radionuclide therapy: An in vivo proof-of-concept study with a new receptor-targeted folate derivative.” Journal of nuclear medicine 53.12 (2012): 1951-1959.
[2] N. Naskar and S. Lahiri. "Theranostic terbium radioisotopes: challenges in production for clinical application." Frontiers in medicine 8 (2021): 675014.
[3] J. Ballof "Radioactive molecular beams at CERN-ISOLDE." CERN PhD Thesis (2021).
[4] M. Au et al. "Production and purification of molecular 225Ac at CERN-ISOLDE." Journal of Radioanalytical and Nuclear Chemistry 334.1 (2025): 367-379.
[5] M. Au et al. "In-source and in-trap formation of molecular ions in the actinide mass range at CERN-ISOLDE." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 541 (2023): 375-379.
[6] R. Wolf et al. “ISOLTRAP's multi-reflection time-of-flight mass separator/spectrometer”, International Journal of Mass Spectrometry Volumes 349–350, 1 September 2013, 123-133

Speaker: Wiktoria Wojtaczka (KU Leuven)

60 Purification of radioisotope beams at the RISIKO off-line RIB facility at Mainz¶

Separation of rare isotopes is of high relevance for a multitude of different applications ranging from the half-life determination of the cosmogenic radionuclide ${}^{53}$Mn for MeaNCoRN [1], over decay measurements of ${}^{55}$Fe for the EMPIR Prima-LTD project [2], ${}^{157}$Tb for studies of nuclear data at the PTB [3], the precise measurement of the decay spectrum of ${}^{163}$Ho for neutrino mass determination in the ECHo project [4], ${}^{226}$Ra as a primary ${}^{222}$Rn emanation standard for the PTB [5], to the use of actinide tracers in environmental sample analysis with accelerator mass spectrometry (AMS). At the 30 keV off-line RISIKO mass separator of the Johannes Gutenberg University in Mainz isotopically pure ion beams of radioisotopes of a multitude of elements can be produced via element-selective resonance ionization with subsequent mass separation in a 60° sector field magnet. These isotopically pure ion beams can then be implanted into target foils with low resputtering rates or focused onto micro absorbers with an area well below 1 mm${}^2$.
In this contribution, the recent activities in the purification of radioisotopes will be presented. Based on the successful implantation of ${}^{55}$Fe into micro calorimeters [6] an extension of the program towards collection of actinide isotopes on target foils was started on ${}^{248}$Cm as tracer for environmental samples. In addition, the isotope separation and purification of ${}^{236}$Np is foreseen. In preparation of these separations the overall efficiencies at the RISIKO mass separator were determined for different actinides to be well above 10 % applying two-step laser ionization processes.
For accurate quantification of the separated sample amounts a new and improved Faraday cup design was developed and characterized over the accessible element range from Z = 13 to Z = 92. Comparative measurements between the traditional and the new Faraday cup design show a significantly underestimated ion current in the previously used Faraday cup design, caused primarily by field ionization of sputtered neutral particles. Low level analyses of the separated ${}^{248}$Cm sample by AMS at ANSTO, Sydney, Australia, validates the accuracy of the new Faraday cup design.
[1] R Dressler et al., J. Phys. G: Nucl. Part. Phys. 39 105201 (2012)
[2] M. Müller et al., Journal of Low Temperature Physics 214:263-271 (2024)
[3] J. Riffaud et al., Applied Radiation and Isotopes 211 (2024)
[4] L. Gastaldo et al., Eur. Phys. J. Spec. Top. 226, 1623-1694 (2017)
[5] F. Mertes et al., Applied Radiation and Isotopes 156 (2020)
[6] T. Niemeyer et al. Applied Radiation and Isotopes 218 (2025)

Speaker: Raphael Hasse (Johannes Gutenberg University Mainz)

61 Studies of (α,n) reactions induced by radioactive ion beams in inverse kinematics for the weak r-process with the EMMA recoil mass spectrometer¶

The weak r-process in core-collapse supernovae is a proposed source of intermediate-mass elements. Under the conditions where the neutrino-driven winds that drive the supernova explosion are slightly neutron-rich, it has been found that (α,n) reactions are the main driver of nucleosynthesis [1]. In contrast with the “main” r-process, nucleosynthesis in the weak r-process proceeds close to the line of stability making it possible to study these reactions using radioactive ion beam facilities. To date, only a few (α,n) reactions on intermediate-mass elements have been studied at the relevant energies.
Recently, experiments have been conducted at the TRIUMF ISAC-II facility, using the EMMA recoil mass spectrometer to separate reaction products from unreacted beam ions and the TIGRESS gamma-ray spectrometer array for coincident gamma ray detection. These studies looked at several (α,n) reactions, each having been identified as significant in astrophysical models of weak r-process nucleosynthesis [2]. This presentation will discuss results from these studies, reporting on measured partial cross-sections, from both the 86Kr(α,n)89Sr experiment and the 94Sr(α,n)97Zr and 93Sr(α,n)96Zr experiments with radioactive beams.

[1] Bliss et al. (2017) J. Phys. G: Nuclear. Part. Phys. 44 054003.
[2] Bliss et al. (2020) Phys. Rev. C. 101 055807.

Speaker: Cameron Angus (TRIUMF)

Banquet¶

Friday, 24 October ¶

Low-energy & in-flight separators II¶

62 Beam Commissioning and First User Experiments at the RAON Low-Energy Experimental Systems¶

The RAON accelerator facility in Korea has recently initiated low-energy nuclear physics experiments using ion beams accelerated by the superconducting linear accelerator SCL3. As part of the Phase-1 operation, three major experimental systems for low-energy experiments—KoBRA (Korea Broad acceptance Recoil spectrometer and Apparatus), NDPS (Nuclear Data Production System), and CLaSsy (Collinear Laser Spectroscopy)—have been successfully installed and commissioned. In 2024, beam commissioning was carried out for each experimental system, and a total of five user experiments were conducted. At KoBRA, secondary rare isotope beams with atomic numbers up to Z ≤ 17 were produced via projectile fragmentation and successfully identified using the Bρ–ΔE–TOF method. At NDPS, the first fast neutron production and detection experiment was performed using a 40Ar beam and EJ-301 detectors, and its performance was verified by measuring neutron-induced gamma rays from activation foils. At CLaSsy, laser spectroscopy experiments were carried out using Na beams produced from the ISOL facility. This presentation reports on the beam commissioning results and technical progress of these low-energy experimental systems, demonstrating RAON’s readiness to support advanced rare isotope beam science.

Speaker: Dr Do Gyun Kim (Institute for Basic Science)

63 Development of high-flux MRTOF isobar separator at SCRIT facility¶

The SCRIT facility at RIKEN recently achieved the world’s first electron scattering experiments with online-produced radioactive isotopes (RIs)[1,2]. The next milestone is an electron scattering experiment using a high-purity ${}^{132}$Sn ion beam. However, the current ISOL-type RI production system at SCRIT, ERIS, inherently produces isobaric contaminants, particularly ${}^{132}$Sb, which impede experimental precision. We are developing a high-flux Multi-Reflection Time-of-Flight (MRTOF) isobar separator to address this challenge, taking advantage of its inherently high mass resolving power.[3]
The required luminosity for electron scattering experiments necessitates processing ion beams at rates up to ${10}^8$ ions per second—approximately four orders of magnitude higher than typical MRTOF specifications. Although high ion flux could substantially degrade mass resolving power due to space-charge effects, the target mass resolution required for separating isobars is around 40,000, significantly lower than the intrinsic resolving power (>${10}^5$) demonstrated in conventional MRTOF systems. The key technical challenge thus lies in optimizing system performance to maintain sufficient resolving power under these extremely high-flux conditions.
A prototype MRTOF system is currently under construction. It comprises an ion trapping section, electrostatic mirrors, and fast kicker electrodes for ion selection. Offline tests with alkali ion sources have been conducted to evaluate transport efficiency, mass resolving power, and electronic system performance. These tests have confirmed promising results, demonstrating a path toward achieving the required operational parameters.
Successful implementation of this MRTOF system will enable production of high-purity, high-intensity, and low-emittance RI beams, significantly enhancing not only electron scattering experiments but also opening avenues for various other precision measurements.
[1] M. Wakasugi et al., Nucl. Instr. and Meth. B317, 668 (2013).
[2] K. Tsukada et al., Phys. Rev. Lett. 131, 092502 (2023).
[3] M. Rosenbusch et al., Nucl. Instr. and Meth. A1047, 167824 (2023).

Speaker: Shun Iimura (Rikkyo University)

64 Production and Identification of Neutron-Rich Isotopes Beyond N=126 Using 238U Projectile Fragmentation at the RIBF BigRIPS Separator¶

Next-generation in-flight radioactive isotope (RI) beam facilities, including the RIKEN Radioactive Isotope Beam Factory (RIBF), the Facility for Rare Isotope Beams (FRIB), and the upcoming Facility for Antiproton and Ion Research (FAIR), primarily use two reaction mechanisms: in-flight fission for medium-mass neutron-rich isotopes and projectile fragmentation for high-purity RI beams near the projectile. The BigRIPS superconducting in-flight separator [1] at RIBF has become a global leader in RI-beam production, combining high-intensity heavy-ion beams with outstanding separation capabilities, resulting in the discovery of nearly 200 new isotopes.

Producing heavy neutron-rich isotopes around and beyond the neutron magic number N=126 remains challenging due to high atomic numbers, multiple charge states, and low production cross sections. To overcome this, we recently produced neutron-rich isotopes with Z=80–90 via projectile fragmentation of a 345 MeV/u U beam on a beryllium target, supported by advanced detectors and detailed simulations. For in-flight separation, the -- method was used, where is the magnetic rigidity and is the energy loss in degraders. Angular slits effectively suppressed fission fragments by exploiting their broader angular distributions. Careful charge-state selection before and after BigRIPS focal planes ensured high transport efficiency and purity.

Particle identification was performed using the TOF-- method [2], where TOF is time-of-flight. A newly developed xenon-filled ionization chamber [3] enabled precise measurements and accurate identification in the heavy mass region. As a result, neutron-rich isotopes in the Z=80–90 region were successfully produced, separated, and identified, providing essential data for future studies of nuclei beyond N=126. This presentation will highlight these results and the optimized separation and identification techniques developed with BigRIPS.

[1] T. Kubo, Nucl. Instr. Meth. B 204, 97 (2003).
[2] N. Fukuda et al., Nucl. Instr. Meth. B 317, 323 (2013).
[3] M. Yoshimoto et al., Prog. Theor. Exp. Phys. ptaf063, 2025.

Speaker: Naoki FUKUDA (RIKEN Nishina Center)

65 SARONA – The SARaf exotic Nuclide fAcility¶

The combination of continuous wave 5 mA proton or deuteron 40 MeV beams on a unique thick GaIn liquid jet target [1] will generate a high-energy neutron rate of more than ${10}^{15}$ neutrons per second at the Soreq Applied Research Accelerator Facility (SARAF), currently under construction in Yavne, Israel [2].
We are currently designing SARONA – SARaf exotic Nuclide fAcility, where the high-energy neutrons, up to ~45 MeV, will impinge on thin natural actinide targets located inside a gas-filled cryogenic stopping cell (CSC) to produce more than ${10}^9$ neutron-rich isotopes per second via neutron-induced fission.
The fission products will be thermalized the CSC, separated and transferred via an ion beam line to a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). SARONA is based conceptually on the FRS Ion Catcher at GSI [3], with a CSC whose architecture is similar to that planned for FAIR [4]. The rate of mass-separated neutron-rich fission products at SARONA is expected to be at a similar level to that of FRIB [5].
In this contribution we will present the simulations and design of the SARONA CSC and its first engineering tests, and the layout of SARONA at the vicinity of the high-rate GaIn neutron source. A preliminary analysis of space charge in the CSC and its effect on maximal extraction rates as a function of push voltage and buffer gas pressure will be shown. We will describe our efforts to maximize the neutron rate at the thin actinide target, while minimizing their rate at the MR-TOF-MS detector and the radiation dose at sensitive electronic equipment. We will discuss the challenges and solutions for installing and operating SARONA in the radiation environment of the high-energy neutron source, considering the effects of direct neutron bombardment and induced residual activation.

[1] I. Eliyahu et al., Nucl. Instr. Meth A 1053, 168320 (2023)
[2] I. Mardor et al., Front. Phys. 11:1248191 (2023)
[3] W. R. Plass et al., Nucl. Instr. Meth B 317, 457 (2013)
[4] T. Dickel et al., Nucl. Instr. Meth B 376 216 (2016)
[5] I. Mardor et al., Eur. Phys. Jour. 54:91 (2018)

Speaker: Dr Israel Mardor (Soreq Nuclear Research Center)

Health Break¶

Instrumentation for RIB experiments¶

66 Recent MR-TOF-MS developments at Jyväskylä¶

During the last decade Multi-Reflection Time-of-Flight Mass-Spectrometers (MR-ToF-MS) [1] have been established as integral parts of radioactive beam facilities. These devices are used to separate and to measure the atomic masses of particularly exotic, short-lived radioactive nuclei to high precision, shedding light on the nuclear forces [2], the composition of neutron stars [3], and the yields of radioactive ion production [4]. An MR-ToF-MS has been integrated to the University of Jyväskylä Ion-Guide Isotope-Separator On-Line (IGISOL) facility [5] and utilized for mass separation and measurements of exotic radioactive nuclei. In this overview, technical developments of the IGISOL MR-ToF-MS and the miniaturized radiofrequency quadrupole cooler-buncher [6]; the recent on-line measurement results, including a solution to the long-standing two-proton decay conundrum of 94Ag(21+); and the results of the latest MR-ToF-MS assisted in-source laser spectroscopy of Ag isotopes are presented.

References

[1] W. R. Plaß, et al., “Multiple-reflection time-of-flight mass spectrometry”, International Journal of Mass Spectrometry, vol. 349-350, pp. 134–144, 2013. doi: 10.1016/j.ijms.2013.06.005.

[2] F. Wienholtz et al. “Masses of exotic calcium isotopes pin down nuclear forces.” Nature vol. 498, pp. 346–349 (2013). doi: 10.1038/nature12226

[3] R. N. Wolf et al. “Plumbing Neutron Stars to New Depths with the Binding Energy of the Exotic Nuclide 82Zn”, Physical Review Letters, vol. 110, iss. 4, 2013. doi: 10.1103/PhysRevLett.110.041101

[4] S. Canarozzo et al. “Isomeric yield ratios and mass spectrometry of Y and Nb isotopes in the neutron-rich N=60 region: the unusual case of 98Y” arXiv 2025 url: https://arxiv.org/abs/2504.11274

[5] I. Moore et al., “Towards commissioning the new IGISOL-4 facility”, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, vol. 317, pp. 208–213, 2013. doi: 10.1016/j.nimb.2013.06.036.

[6] V. A. Virtanen, et al., “Miniaturised cooler-buncher for reduction of longitudinal emittance at IGISOL”, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment vol. 1072, 170186, 2025. doi: 10.1016/j.nima.2024.170186.

Speaker: Ville Virtanen (University of Jyväskylä)

67 HISTARS: A High-Performance Detector for Nuclear Excited-State Lifetimes at HIE-ISOLDE¶

The ISOLDE facility at CERN is one of the most versatile and prolific facilities worldwide for the production of exotic isotopes using the Isotope Separation On-Line (ISOL) method. The HIE-ISOLDE project has realized a cutting-edge superconducting post-accelerator capable of delivering radioactive ion beams with energies up to 10 MeV/u, making ISOLDE a unique facility worldwide to accelerate medium and heavy isotopes within this energy range.

To exploit the vast possibilities offered for research in nuclear structure, nuclear astrophysics and other fields, the HIE-ISOLDE Timing Array for Reaction Studies (HISTARS) project aims at building a detection device for the measurement of lifetimes of excited states populated in reactions. Nuclear excited-state lifetimes are essential to have direct access to electromagnetic transition rates, which are sensitive to the details of nuclear wavefunctions.

HISTARS combines a charged particle inner detector system with enhanced capabilities for reaction tagging with excellent timing response and an external gamma fast-timing array based on LaBr${}_3$(Ce) detectors. The system aims to benefit from recent advancements in instrumentation and electronics, utilizing improvements in digital signal processing and innovative analysis techniques based on genetic algorithms. The project will expand research opportunities for the large community of accelerated beam users at ISOLDE.

The presentation will address the HISTARS conceptual design, the technical design study including Monte Carlo simulations, and the performance evaluation of fast-scintillator systems for gamma rays and charged particles. Test physics cases to showcase the potential of the instrument will be also introduced.

Speaker: Nikita Bernier (Universidad Complutense de Madrid)

68 BYACO: A Unified Platform for Analysis, Control, and Operation in Nuclear Physics Experiments¶

Production of radioactive ion (RI) beams at RIKEN RIBF using the BigRIPS fragment separator requires dedicated studies of RI-beam separation and particle identification (PID), particularly for heavy-ions or low-energy beams. Challenges arise from the charge-state change and inaccurate energy loss predictions. While post-experiment analysis provides valuable insights for further improvements, real-time feedback based on complex analyses during experiments would substantially improve data quality by optimizing beamline and detector settings. To address these issues, we have developed BYACO (BeYond Analysis, Control, or Operation alone), a novel unified platform that integrates analysis tools, beamline and detector control systems, and data acquisition (DAQ) [1]. This platform enables advanced, real-time operation and optimization of RI-beam production and other experiments.

BYACO functions as a platform where each component shares real-time information and can be accessed via web APIs. A user-friendly front-end interface is provided through a web application. Furthermore, we have developed near-line analysis software and analysis programs that can execute offline-developed macros and connect to BYACO. These developments have allowed us to successfully implement sequences that execute complex analyses and modify settings based on the analysis results, such as a task of an automatic RI-beam tuning [2]. The energy-control tool of slowed-down RI beam was also developed. As experimental procedures become increasingly complex, and subsequently require more functionality, the agile development is crucial. Therefore, the server-side and front-end of BYACO are constructed by combining loosely coupled components. For future integration of machine learning and AI techniques, we plan to migrate to a microservice architecture, which is well-suited for the agile development using many loosely coupled components.

In this conference, we will introduce the development of BYACO and present examples of its applications and future perspectives.

[1] T. Sumikama et al., RIKEN Accel. Prog. Rep. 54, 82 (2021).

[2] Y. Shimizu et al., RIKEN Accel. Prog. Rep. 54, 83 (2021).

Speaker: Toshiyuki Sumikama (RIKEN Nishina Center)

Closing Remarks¶

Transfer to TRIUMF (bagged lunches provided)¶

TRIUMF Tour¶