New Insights into Particle Detection with Superheated Liquids

TL;DR

This paper presents new calibration results for superheated liquid droplet detectors used in dark matter searches, analyzing their responses to various radiation sources and developing a model for bubble growth dynamics to improve particle discrimination.

Contribution

It introduces a new model linking acoustic signals to bubble growth, enhancing understanding of particle interactions in superheated liquid detectors.

Findings

Different responses observed for alpha particles and recoil nuclei.

Energy thresholds for alpha-emitters compared with neutron tests and theory.

Model relates acoustic signal intensities to bubble growth dynamics.

Abstract

We report new results obtained in calibrations of superheated liquid droplet detectors used in dark matter searches with different radiation sources (n,$\alpha$,$\gamma$). In particular, detectors were spiked with alpha-emitters located inside and outside the droplets. It is shown that the responses are different, depending on whether alpha particles or recoil nuclei create the signals. The energy thresholds for $\alpha$-emitters are compared with test beam measurements using mono-energetic neutrons, as well as with theoretical predictions. Finally a model is presented which describes how the observed intensities of particle induced acoustic signals can be related to the dynamics of bubble growth in superheated liquids. An improved understanding of the bubble dynamics is an important first step in obtaining better discrimination between particle types interacting in detectors of this kind.