Identifying drivers of energy resolution variation in multi-KID phonon-mediated detectors

TL;DR

This paper investigates the causes of energy resolution variation among Kinetic Inductance Detectors (KIDs) on silicon substrates, aiming to improve their performance for rare-event detection in physics experiments.

Contribution

It introduces a first principles approach to identify drivers of resolution variation, highlighting quality factor differences as a key factor.

Findings

Quality factor differences likely cause resolution variation

Pulsing neighboring KIDs helps analyze signal generation

Energy resolution varies 5 to 125 eV among identical KIDs

Abstract

Phonon-mediated particle detectors employing Kinetic Inductance Detectors (KIDs) on Silicon substrates have demonstrated both O(10) eV energy resolution and mm position resolution, making them strong candidates for instrumenting next generation rare-event experiments such as in looking for dark matter or in neutrino measurements. Previous work has demonstrated the performance of an 80-KID array on a Si wafer, however current energy resolution measurements show a 25x difference between otherwise identical KIDs on the same wafer - between 5 to 125 eV on energy absorbed by the KID. Here, we use a first principles approach and attempt to identify the drivers behind the resolution variation. In particular, we analyze a subset of 8 KIDs using the unique approach of pulsing neighboring KIDs to generate signals in the target. We tentatively identify differences in quality factor terms as the likely culprit for the observed variation.