Speaker
Description
A decade ago, the SPIRAL1 (Système de Production d’Ions Radioactifs Accélérés en Ligne) [1] facility went through a major upgrade at GANIL (Grand Accélérateur National d'Ions Lourds). Based on the ISOL (Isotope Separation On Line) technique and exploiting a TISS (Target and Ion Source System), this facility uses several sources to deliver RIBs (Radioactive Ion Beams). However, only the FEBIAD (Forced Electron Beam Ionization by Arc Discharge) source [2] enables an efficient production of metallic isotopes such as Fe, Co, and Ni.
A production test of a TISS was conducted in July 2024 using a $\displaystyle{{}^{58}_{}}$Ni primary beam on a graphite target coupled with the FEBIAD. The produced RIBS were guided to the SPIRAL1 low-energy beam identification station [3]. Several isotopes of interest were detected, including $\displaystyle{{}^{56}_{}}$Ni, a double magic nuclide strongly requested in nuclear structure studies. In 2025, a new experiment is planned to accelerate and strip this particular ion beam to suppress isobaric contamination. Its yield will be significantly reduced due to charge breeding ($\sim 5 - 10 \%$), acceleration and stripping ($\sim 20 \%$) losses. Therefore, the TISS production rates must be increased to meet the demand for physics experiments investigating new regions of the nuclide chart.
Developments are underway at SPIRAL1 to improve the release efficiency of radionuclides out of the TISS, a process largely governed by the competition between their half-lives and release times. To this end, the target cavity and the source must be maintained at high temperatures ($\sim 2000$ ◦C) to accelerate diffusion from the target and enhance surface desorption of the nuclides effusing towards the source. This will reduce the release time, minimize radioactive decay losses, and thereby lead to higher yields.
To further optimize the release characteristics of the TISS, thermal simulations are essential and require an accurate collection of the thermal properties involved. An experimental set-up [4] has been renovated to measure these properties by heating material samples in a vacuum chamber. Based on these results, Ansys [5] will be used to construct a parametric finite element model of the TISS, allowing for changes in its geometry. This model will enable optimization of the design to achieve high and homogeneous temperatures throughout the TISS.
References
[1] V. Bosquet et al., “Improvement of the FEBIAD ion source at SPIRAL1”, Journal of Physics: Conference Series, vol. 2244, p. 7, 2022. doi: 10.1088/1742-6596/2244/1/012071.
[2] L. Penescu, R. Catherall, J. Lettry, and T. Stora, “Development of high efficiency versaltile arc discharge ion source at CERN ISOLDE”, Review of Scientific Instruments, vol. 81, p. 10, 2010.
[3] G. Grinyer et al., “Upgrade of the SPIRAL identification station for high-precision measurements of nuclear β decay”, Nuclear Instruments and Methods in Physics Research A, vol. 741, pp. 18–25, 2014. doi: 10.1016/j.nima.2013.11.106.
[4] K. Venkateswarlu, “Development of an innovative ISOL system for the production of short lived neutron-deficient ions.”, Physics, Ph.D. dissertation, Caen : Université de Caen Normandie, 2018.
[5] PyAnsys, “Welcome to PyMAPDL”, (accessed 12 mars 2025). [Online]. Available:
https://mapdl.docs.pyansys.com/version/stable/index.html.
| Email address | erwan.levillain@ganil.fr |
|---|---|
| Supervisor's Name | Pascal Jardin |
| Supervisor's email | pascal.jardin@ganil.fr |
| Funding Agency | CEA |
| Classification | Isotope production, target, and ion source techniques |
