CdZnTe detectors tested at the DAΦNE collider for future kaonic atoms measurements

Abstract

The SIDDHARTA-2 collaboration at the INFN Laboratories of Frascati (LNF) aims to perform important measurements on kaonic atoms. In parallel to the groundbreaking kaonic deuterium measurement, presently running on the DAΦNE collider at LNF, we plan to install additional detectors. The aim is to perform further kaonic atoms’ studies, taking advantage of the unique low energy and low momentum spread K− beam delivered by the at-rest decay of the ϕ meson. CdZnTe devices are ideal for detecting transitions toward both the upper and lower levels of intermediate-mass kaonic atoms, like kaonic carbon and aluminium. Measuring these transitions can have an important impact on the strangeness sector of nuclear physics. We present the results obtained in two preliminary tests conducted at DAΦNE in view of measurements foreseen in 2024, with the twofold aim to tune the timing window required to reject the extremely high electromagnetic background, and to quantify the readout saturation effect due to the high rate when placed close to the Interaction Region (IR). In the first test we used a RITEC device and electronics, while for the second one commercial REDLEN detectors were coupled to a frontend electronics customized at the University of Palermo. The results confirmed the possibility of finding and matching a proper timing window to identify the signal events and proved the better performance in terms of energy resolution of the REDLEN technology with a custom frontend electronics. In both cases, strong saturation effects were confirmed, accounting for a loss of almost 90% of the events, which will be overcome by a dedicated shielding structure foreseen for the final experimental setup.