Ponente
Descripción
DEcay SPECtroscopy (DESPEC) experiments [1] are part of the NUSTAR collaboration, one of the four scientific pillars of the FAIR/GSI facility. Those experiments aim at studing the properties of exotic nuclei using high- resolution decay spectroscopy. They are currently performed at the FRagment Separator (FRS) and will be, in the future, at the Super-FRS facility at FAIR, at GSI. The DESPEC setup comprises a series of state-of-the-art detection systems tailored to the experimental goals. The heavy ion implantation stack is the core of this setup: a so-called ‘snout’ wherein exotic ions are implanted in detectors. This stack comprises usually 1 to 3 layers of highly- segmented AIDA double-sided silicon strip detectors [2] which are sandwiched between two “βPlast” plastic
scintillator detectors for beta-particles, placed upstream and downstream. Implanted ions emit gamma-rays that can then be measured by different systems such as the FATIMA array of LaBr3(Ce) detectors [3], DEGAS HPGe detectors [4] or the DTAS Total Absorption Spectrometer, which enables fast-timing, high-precision or high-efficiency measurements, respectively.
The βPlast detectors are of paramount importance. They are indeed able to provide excellent timing resolution for β particles emitted by the exotic ions of interest to enable β- timing-measurements as well as a veto for punchthrough events, for example. Several configurations of those detectors have been used in recent years
during FAIR Phase-0 experiments. The last one is composed of a 247.50.3 cm3 rectangular monolithic plastic sheet coupled at edges by an optical silicon pad with arrays of 3*3 mm2 aligned silicon PhotoMultipliers (SiPMs).
Each long and short side contains respectively 48 and 16 aligned SiPMs, with adjacent pairs of SiPMs gathered to form, in total, 64 channels per detector. Those are connected to the TAMEX multi-channel TDCs, developed in-house at GSI, in order to exploit the fast-timing characteristics of the βPlast.
This presentation will focus on the technical details of the detectors and on its characterisation. It will then describe the recent development that aimed at improving detector performance and accessing the position of a particle by creating a lookup table using time-differences between the SiPMs. Finally, it will give an overview of future development work and redesign.
[1] A.K. Mistry et al., The DESPEC setup for GSI and FAIR, Nucl. Instrum. Methods in phys. Res. A 1033, 166662 (2022)
[2] O. Hall et al., The Advanced Implantation Detector Array, Nucl. Instrum. Methods in phys. Res. A 1050, 168166 (2023)
[3] M. Rudigier et al., FATIMA – Fast TIMing Array for DESPEC at FAIR, Nucl. Instrum. Methods in phys. Res. A 969, 163967 (2020)
[4] G.S. Li et al., Characteristics of the DEGAS-FATIMA Hybrid setup for the DESPEC program at NUSTAR, Nucl. Instrum. Methods in phys. Res. A 987, 164806 (2021)
