Final results of CALDER: Kinetic inductance light detectors to search for rare events

TL;DR

The CALDER project developed a cryogenic light detector with high sensitivity, fast response, and scalable design, suitable for rare event searches like neutrino-less double beta decay.

Contribution

This paper presents the final prototype of a kinetic inductance light detector with improved resolution and response time, demonstrating its potential for large-scale rare event experiments.

Findings

Energy resolution of 34±1(stat)±2(syst) eV RMS

Response time of 120 microseconds

Scalable design suitable for large experiments

Abstract

The next generation of bolometric experiments searching for rave events, in particular for the neutrino-less double beta decay, needs fast, high-sensitivity and easy-to-scale cryogenic light detectors. The CALDER project (2014-2020) developed a new technology for light detection at cryogenic temperature. In this paper we describe the achievements and the final prototype of this project, consisting of a $5\times5$ cm$^2$, 650 $\mu$m thick silicon substrate coupled to a single kinetic inductance detector made of a three-layer aluminum-titanium-aluminum. The baseline energy resolution is 34$\pm$1(stat)$\pm$2(syst) eV RMS and the response time is 120 $\mu$s. These features, along with the natural multiplexing capability of kinetic inductance detectors, meet the requirements of future large-scale experiments.