Quantification of the directional detection capability of the DRIFT-IIe dark matter search detector via the range of nuclear recoil tracks in two dimensions
Date
2021
Authors
Schuckman, Frederick G., II, author
Harton, John, advisor
Toki, Walter, committee member
Mooney, Michael, committee member
Marconi, Mario, committee member
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Abstract
Evidence suggests that 83% of the matter content of the universe is dark matter. Despite its ubiquity, the identity of this matter is unknown. It is thought that a halo of dark matter surrounds and is distributed throughout our galaxy. The Weakly Interacting Massive Particle (WIMP) has been a popular dark matter candidate. As we move through this halo it should appear as a wind of WIMPs incident upon us. A properly-placed detector could have this wind blow through its top face at one time in the day, and through a side face 12 sidereal hours later. DRIFT-IIe is a low-pressure gas negative-ion time projection chamber designed for direct and directional detection of WIMPs elastically scattering from gas nuclei. Partial directional information of a WIMP recoil could be extracted by measuring the range of the track of ionization that it produces in two dimensions. To study this signature, the detector was exposed to a source of neutrons in a series of runs. In one run the source was placed above the detector and in a second run the source was placed to the side of the detector. Neutron recoils mimic those expected from WIMPs, and the source placement mimics a specific WIMP wind direction. For the two runs, the range information was compared with a Monte Carlo resampling test. It was found on average 302 +/- 4 neutron recoils, sampled with WIMP-like energy spectra, are required along each of these axes to discern the two populations with a significance of 3σ.
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Subject
directional
dark matter
nuclear recoil