Characterization of the Response of Superheated Droplet (Bubble) Detectors

TL;DR

This paper discusses the characterization of superheated droplet detectors used in dark matter searches, focusing on their response to nuclear recoils and the results of simulations and experiments validating their effectiveness.

Contribution

It provides a detailed analysis of the detector response to neutrons and alpha particles, supporting the use of superheated droplet detectors in dark matter detection.

Findings

Detector response to neutrons characterized

Simulation results align with experimental data

Validated the technique for dark matter searches

Abstract

The PICASSO project is a cold dark matter (CDM) search experiment relying on the superheated droplet technique. The detectors use superheated freon liquid droplets (active material) dispersed and trapped in a polymerized gel. This detection technique is based on the phase transition of superheated droplets at room or moderate temperatures. The phase transitions are induced by nuclear recoils when undergoing interactions with particles, including CDM candidates such as the neutralinos predicted by supersymmetric models. The suitability of the technique for this purpose has been demonstrated by R&D studies performed over several years on detectors of various composition and volume. Simulations performed to understand the detector response to neutrons and alpha particles are presented along with corresponding data obtained at the Montreal Laboratory.