CryoCsI, a subsystem of COHERENT experiment for CEvNS and beyond

We present advantages that motivate the development of a 10 kg-scale cryogenic pure CsI detector as a new subsystem in the COHERENT experiment. This detector aims to significantly enhance our precision measurements of coherent elastic neutrino-nucleus scattering (CEvNS), a process crucial for probing beyond-the-Standard-Model physics. By operating undoped CsI crystals at cryogenic temperatures (40-80 K), we anticipate achieving a significantly lower energy threshold compared to the CsI[Na] detector that first observed CEvNS. This, combined with improved background reduction techniques, is expected to result in an order-of-magnitude increase in detection rate.

A 10 kg prototype operating at 77 K is currently under development by COHERENT. Ongoing research efforts are focused on optimizing detector performance through lower temperature operation, enhanced photodetection efficiency, advanced background rejection techniques, and a deeper understanding of the crystal's response to nuclear recoils.