The 59th Winter Nuclear & Particle Physics Conference (WNPPC2022)

Nucleation Efficiency of Nuclear Recoils in Bubble Chambers

15 Feb 2022, 11:00

12m

virtual

Dark Matter Searches Dark Matter Searches

Speaker

Daniel Durnford (University of Alberta)

Description

Bubble chambers using liquid xenon (and liquid argon) have been operated (resp. planned) by the Scintillating Bubble Chamber (SBC) collaboration for GeV-scale dark matter searches and to detect CEvNS from nuclear reactors. This will require a robust calibration of the nucleation efficiency of low-energy nuclear recoils in these target media. Such a program has been carried out by the PICO collaboration, which aims to directly detect dark matter using ${\mathrm{C}}_3{\mathrm{F}}_8$ bubble chambers. Neutron calibration data from mono-energetic neutron beam and AmBe source has been collected and analyzed, leading to a global fit of a generic nucleation efficiency model for carbon and fluorine recoils, at thermodynamic thresholds of $2.45$ and $3.29\mathrm{keV}$. Fitting the many-dimensional model to the data (34 free parameters) is a non-trivial computational challenge, addressed with a custom Markov Chain Monte Carlo approach, which will be presented. Parametric MC studies undertaken to validate this methodology are also discussed. This fit paradigm demonstrated for the PICO calibration is applied to existing scintillating bubble chamber calibration data, and preliminary results will be presented.

Presentation materials

Nucleation efficiency of nuclear recoils in bubble chambers