Speaker
Description
The GADAST detector array [1] is being developed within the EXPERT project [3] of the Super-FRS Experiment Collaboration at FAIR [2]. Its principal task is to tag γ-ray de-excitation of daughter nuclei produced in exotic radioactive decays, and to detect of protons and other light charged particles emitted with sufficiently large transverse momentum. Previous characterization of the GADAST CsI(Tl) modules demonstrated their compliance with the technical requirements of the collaboration, including energy resolution and light-output uniformity, and provided the basis for their implementation in the ExpertRoot simulation and analysis framework [4].
New characterization campaign of GADAST CsI(Tl) modules equipped with digital electronics will be reported. During the measurements performed in 2026 at the Cyclotron Centre Bronowice, IFJ PAN, the response of the modules was studied using $^{137}$Cs and $^{60}$Co γ-ray sources, and using scattered proton beams with energies from 70 to 180 MeV. The signals were digitized with a CAEN V1730 digitizer. The data analysis included a comparison of results obtained with standard CAEN firmware and with dedicated offline processing of the recorded waveforms.
The proton-beam measurements extend the characterization towards charged particles. The main emphasis will be placed on the reconstruction of the deposited energy and on pulse-shape observables extracted from the digitized waveforms, in particular the charge integrated in different time gates and the relative contribution of the fast and slow scintillation components.
Preliminary results indicate that the spectroscopic performance obtained with digital electronics is comparable to that achieved in the previous characterization. In addition, a particle-dependent differences in pulse-shape were observed, what shows the possibility of using waveform-based pulse-shape analysis for particle identification in future experiments with GADAST.
References:
[1] B. Khamidullin et al., GADAST CsI(Tl) modules performance tests and response simulations, submitted to Nuclear Instruments and Methods in Physics Research A.
[2] H. Geissel et al., EXPERT studies at the Super-FRS spectrometer, in: Exotic Nuclei, World Scientific, 2015.
[3] 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.
[4] Expertroot repository. URL https://git.jinr.ru/