[Bubble] Modeling emission of acoustic energy during bubble expansion in PICO bubble chambers

[Jay Benesch]

https://arxiv.org/abs/1906.04712

Modeling emission of acoustic energy during bubble expansion in PICO 
bubble chambers
Tetiana Kozynets, Scott Fallows, Carsten B. Krauss
(Submitted on 11 Jun 2019)

     The PICO experiment uses bubble chambers filled with superheated 
C3F8 for spin-dependent WIMP dark matter searches. One of the main 
sources of background in these detectors is alpha particles from decays 
of environmental 222Rn, which nucleate bubbles that are visually 
indistinguishable from WIMP candidate events. Alpha-induced bubbles can 
be discriminated acoustically, because the signal from alpha events is 
consistently larger in magnitude than that from nuclear recoil/WIMP-like 
events. By studying the dynamics of bubbles nucleated by these two types 
of ionizing radiation from the first stages of their growth, we present 
a physical model for the acoustic discrimination for the first time. The 
distribution of acoustic energies that we generate for a simulated 
sample of bubble nucleations by alpha particles and nuclear recoils is 
compared directly to the experimental data.

Comments: 	15 pages, 17 figures
Subjects: 	Instrumentation and Detectors (physics.ins-det); 
Computational Physics (physics.comp-ph)
Cite as: 	arXiv:1906.04712 [physics.ins-det]