The Active Target ATS (Active Target for SPES) is a new time-projection chamber designed for reaction and decay studies with nuclei far from stability. This kind of instrument, initially developed for high-energy physics, has found profitable applications in medium- and low-energy nuclear physics as shown by a successful series of experiments.
The physics cases for the new-generation active target are related to the ongoing developments of facilities for radioactive ion beams. Thanks to its flexibility, this instrument will be capable of taking advantage of the most exotic beams which will become available at the SPES facility under construction at the Legnaro National Laboratories in Italy. Particular attention will also be paid to coupling it with ancillary detectors for both charged and neutral (gamma and neutrons) particles.
In particular, in the present study, we will focus the attention on the neutron ancillary detectors.
The proposed solution takes into account a compact device and the capability of the system to discriminate, by performing pulse shape analysis, neutrons from the high gamma background.
A potential compact system aimed to discriminate neutrons from gamma ray events, using digital Pulse Shape Discrimination (PSD) techniques, can take advantage of recent improvements in silicon photomultiplier (SiPM) technology and the development of new plastic scintillators exhibiting the PSD phenomena.
Our presentation will be focused on the first studies of SiPM coupled with CsI(Tl), EJ-276G and EJ-276 scintillators with different configurations, such as: different SiPM models (Advansid and Ketek), different area coverage (from 3 mm x 3 mm to 17 mm x 17 mm) and different preamplifiers.
Moreover, we will show the comparison of PSD performances of plastic scintillators ranging from 25 mm to 70 mm diameter size, using the best SiPM readout configuration.