MIMAC low energy electron-recoil discrimination measured with fast neutrons

TL;DR

This paper presents a new multivariate analysis method for electron-recoil discrimination in the MIMAC dark matter detector, achieving high rejection power and efficiency based on experimental and simulated data.

Contribution

It introduces an original multivariate analysis technique for electron event rejection in MIMAC, demonstrating high discrimination power with experimental and simulated data.

Findings

Achieved a rejection power of 10^5 for electron/recoil discrimination.

Estimated a nuclear recoil efficiency of 86.49% at full energy range.

Reaching a 10^5 electron rejection power with high efficiency.

Abstract

MIMAC (MIcro-TPC MAtrix of Chambers) is a directional WIMP Dark Matter detector project. Direct dark matter experiments need a high level of electron/recoil discrimination to search for nuclear recoils produced by WIMP-nucleus elastic scattering. In this paper, we proposed an original method for electron event rejection based on a multivariate analysis applied to experimental data acquired using monochromatic neutron fields. This analysis shows that a $10^5$ rejection power is reachable for electron/recoil discrimination. Moreover, the efficiency was estimated by a Monte-Carlo simulation showing that a 105 electron rejection power is reached with a $86.49\pm 0.17$\% nuclear recoil efficiency considering the full energy range and $94.67\pm0.19$\% considering a 5~keV lower threshold.