Speaker
Description
The G-22-00111 experiment was performed at the FRS facility at GSI within the EXPERT programme [1] being a part of Super-FRS Experiment Collaboration [2]. The experiment was aimed at the investigation of very proton-rich light systems, including the search for the four-proton decay of $^7$C. In the experiment, secondary $^9$C and $^7$Be beams, produced from a primary $^{12}$C beam with energy 860 MeV/nucleon, were transported to physical beryllium secondary target.
Performance of the EXPERT tracking setup, with particular emphasis on the FOOT single-sided silicon strip detectors [3] will be discussed. Eight FOOT detectors, arranged in four pairs, were installed downstream of the secondary target and used for detection and tracking of protons and light fragment emitted from decays of nuclei of interest. The setup also included ALPIDE pixel detectors, while the standard FRS detector system provided event-by-event identification of beam particles and light fragment. The second half of the FRS was tuned to register $^3$He and $^4$He fragments.
Preliminary analysis of the FOOT data demonstrates the capability of the setup to detect proton hits and to reconstruct multi-track events originating from a common reaction vertex. As a benchmark channel for the analysis, we use the population of $^{6}$Be (from the fragmentation of the $^7$Be secondary beam on the beryllium target). The decay of $^6$Be to $^4$He and two protons leads to a well known three-body final state [4], in which two proton tracks and helium fragment track can be measured in the FOOT detectors. The standard FRS detector system provides event-by-event beam identification and additional constraints on the reaction channel.
The reconstruction of 2p+$^4$He events from $^6$Be will be used to develop and validate the analysis procedure, including track and vertex reconstruction, particle identification, and decay-energy reconstruction. This methodology will then be extended to more complex nuclear systems, in particular to the search for $^7$C candidates decaying into $^3$He+4p.
References:
[1] H. Geissel et al., EXPERT studies at the Super-FRS spectrometer, in: Exotic Nuclei, World Scientific, 2015.
[2] J. Äystö et al., Experimental program of the Super-FRS collaboration at FAIR and developments of related instrumentation, Nucl. Instrum. Methods Phys. Res. B 376 (2016) 111–115.
[3] G. Silvestre et al., Test of a prototype Microstrip Silicon Detector for the FOOT experiment, J. Phys.: Conf. Ser. 2374, 012065 (2022)
[4] V. Chudoba et al., Three-body correlations in direct reactions: Example of $^6$Be populated in the (p,n) reaction, Phys. Rev. C 98, 054612 (2018)