Energy resolution and efficiency of phonon-mediated Kinetic Inductance Detectors for light detection

TL;DR

This paper reports on the development and testing of phonon-mediated Kinetic Inductance Detectors (KIDs) for cryogenic light detection, demonstrating promising energy resolution and efficiency for rare event searches.

Contribution

It introduces a phonon-mediated KID detector prototype with large active area, calibrated with optical and X-ray signals, showing improved energy resolution and efficiency.

Findings

Noise resolution of 154 eV achieved

Detector efficiency of 18% demonstrated

Prototype successfully calibrated with optical pulses and X-rays

Abstract

The development of sensitive cryogenic light detectors is of primary interest for bolometric experiments searching for rare events like dark matter interactions or neutrino-less double beta decay. Thanks to their good energy resolution and the natural multiplexed read-out, Kinetic Inductance Detectors (KIDs) are particularly suitable for this purpose. To efficiently couple KIDs-based light detectors to the large crystals used by the most advanced bolometric detectors, active surfaces of several cm$^2$ are needed. For this reason, we are developing phonon-mediated detectors. In this paper we present the results obtained with a prototype consisting of four 40 nm thick aluminum resonators patterned on a 2$\times$2 cm$^2$ silicon chip, and calibrated with optical pulses and X-rays. The detector features a noise resolution $\sigma_E=154\pm7$ eV and an (18$\pm$2)$\%$ efficiency.