Observables for Recoil Identification in High-Definition Gas Time Projection Chambers

Abstract

Directional detection of nuclear recoils is broadly desirable in nuclear and particle physics. At low recoil energies, this capability may be used to confirm the cosmological origin of a dark matter signal, to penetrate the so-called neutrino floor, or to distinguish between different neutrino sources. Gas Time Projection Chambers (TPCs) can enable directional recoil detection if the readout granularity is sufficiently high, as is the case when micro-pattern gaseous detectors (MPGDs) are utilized. A key challenge in such detectors is identifying and rejecting background electron recoil events caused by gamma rays from radioactive contaminants in the detector materials and the environment. We define new observables that can distinguish electron and nuclear recoils, even at keV-scale energies, based on the simulated ionization's topology. We perform a simulation study that shows these observables outperform the traditionally used discriminant, dE/dx, by up to three orders of magnitude. Furthermore, these new observables work well even at ionization energies well below 10 keV and remain robust even in the regime where directionality fails.

References in corpus (22)

• A review of the discovery reach of directional Dark Matter detection
• The case for a directional dark matter detector and the status of current experimental efforts
• Readout technologies for directional WIMP Dark Matter detection
• Low Threshold Results and Limits from the DRIFT Directional Dark Matter Detector
• Directional recoil detection
• CYGNUS: Feasibility of a nuclear recoil observatory with directional sensitivity to dark matter and neutrinos
• Interfacing Geant4, Garfield++ and Degrad for the Simulation of Gaseous Detectors
• The Directional Dark Matter Detector
• Radon in the DRIFT-II directional dark matter TPC: emanation, detection and mitigation
• 3-D Tracking of Nuclear Recoils in a Miniature Time Projection Chamber
• GEM-based TPC with CCD Imaging for Directional Dark Matter Detection
• CYGNO: a gaseous TPC with optical readout for dark matter directional search
• Identification of low energy nuclear recoils in a gas TPC with optical readout
• Compact, directional neutron detectors capable of high-resolution nuclear recoil imaging
• Absolute Position Measurement in a Gas Time Projection Chamber via Transverse Diffusion of Drift Charge
• Background Rejection in the DMTPC Dark Matter Search Using Charge Signals
• Background Rejection in the DMTPC Dark Matter Search Using Charge Signals
• MIMAC low energy electron-recoil discrimination measured with fast neutrons
• Low energy electron/recoil discrimination for directional Dark Matter detection
• Performance of the GridPix detector quad
• MIMAC: A micro-tpc matrix for dark matter directional detection
• In situ measurement of the electron drift velocity for upcoming directional Dark Matter detectors