Characterization of monolithic SDD arrays and SFERA ASIC for the SIDDHARTA experiment

This work deals with the first characterization results of an X-ray detection module developed within the scope of SIDDHARTA experiment. SIDDHARTA is a nuclear physics experiment aimed at the study of strong nuclear interactions using exotic atoms. This is achieved using monolithic arrays of Silicon Drift Detectors (SDDs), each consisting of eight SDD elements arranged in a 2×4 format (total area 18×34 mm
²
). A total of 48 SDD arrays arranged on a gantry structure are required to perform the experiment. Each SDD element is coupled to a CUBE pre-amplifier with the consequent shaping amplifier and complementary analog electronic stages implemented in a custom developed 16-channel SFERA chip. During the experiment, SDD arrays must be cooled down to cryogenic temperature below 120 K to perform X-ray spectroscopy to assess spread/shift of energy levels of exotic kaonic atoms. Alongside the cryogenic operation, the X-ray spectrometer needs to operate with a linearity of around 1
⁰
/
₀₀
with an output stability of a few eV/day. This work describes the preliminary characterization results of cryogenically cooled 2×4 SDD arrays readout by SFERA chip. These include X-ray spectroscopy, stability and linearity performances.