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

Data Acquisition and Waveform Analysis Techniques for Identifying Alpha-Condensate States in $^{20}$Ne

Not scheduled

20m

Chateau Fairmont Whistler

Poster contribution Instrumentation for radioactive ion beam experiments

Speaker

Mr Shotaro Maesato (the University of Osaka)

Description

Understanding alpha-condensate states is essential for investigating the properties of nuclear matter in low-density regions. Theoretically, such states are expected to exist in nuclei with mass number $A < 40$. There has been a general consensus that the ground state ($0^+_1$) of $^8$Be and the $0^+_2$ state of $^{12}$C correspond to 2$\alpha$ and 3$\alpha$ condensate states, respectively. However, the existence of alpha-condensate states in other nuclei has not yet been confirmed.

Our group is planning to conduct an experiment to search for a 5$\alpha$ condensate state in $^{20}$Ne at the Research Center for Nuclear Physics, the University of Osaka. A 400-MeV alpha-particle beam is impinged on a $^{20}$Ne target. Inelastically scattered alpha particles are measured using Grand Raiden, a high-resolution magnetic spectrometer, to determine the excitation energy of the recoil nucleus. The decay particles from the recoil nucleus are measured by silicon detectors to reveal the decay modes.

There are two main points in this experiment. The first is to identify coincident events between Grand Raiden and Si detectors. The Grand Raiden is based on a trigger-less streaming DAQ system. On the other hand, Si detectors use a trigger-based DAQ system. Reconstructing events between these two systems, which have different data acquisition methods, requires a creative approach. We solved the issue by reading the accepted trigger signal from Si detectors with the Grand Raiden system. The second point is the method for identifying decay particles. Since the decay particles in this experiment have low energy and stop at a single-layer detector, conventional particle identification methods such as the $E$-$\Delta E$ method and TOF cannot be used. Therefore, we used a high-sampling-rate digitizer to acquire silicon waveforms and then applied unique waveform analysis. This analysis allowed us to identify particles in the region above 2 MeV.

This presentation will discuss the method of event reconstruction while using two different DAQ systems, the data acquisition efficiency, and the technique for particle identification using waveform analysis with Si detectors.