A low energy rare event search with the MAJORANA DEMONSTRATOR

Abstract

The Majorana Demonstrator is sensitive to rare events near its energy threshold, including bosonic dark matter, solar axions, and lightly ionizing particles. In this analysis, a novel training set of low energy small-angle Compton scatter events is used to determine the efficiency of pulse shape analysis cuts, and we present updated bosonic dark matter and solar axion results from an 11.17 kg-y dataset using a 5 keV analysis threshold.

Projected WIMP sensitivity of the CDEX-50 dark matter experiment

“…During this time, the specific activities of cosmogenic radionuclides will decrease through decay. The manufacturing/processing steps and specific activities of the considered radionuclides are presented in tables 2 and 3, respectively, compared with a competitive Ge-based experiment, the MAJORANA DEMONSTRATOR (denoted as MJD) [45][46][47][48][49], in cosmogenic radionuclide-induced background sensitivity. The 3 H radioactivity of CDEX-50, which contributes most in the low-energy region, is lower than that of MJD by a factor of ∼6.…”

“…Manufacturing/processing step CDEX-50 MJD Shielding 3. Specific activities of the cosmogenic radionuclides of the germanium crystal after 3 years of cooling down, along with MJD with approximately 4 years of cooling down derived from best fit based on the observed spectrum [46,48]. The specific activity of 68 Ga is considered the same as 68 Ge because the progeny of 68 Ge, 68 Ga has a much shorter half life compared to 68 Ge.…”

“…The manufacturing/processing steps of the germanium crystal and detector[43] of CDEX-50, along with those of MJD[45][46][47][48][49]. The unit duration of each manufacturing/processing step is day.…”

Performance of a convolutional autoencoder designed to remove electronic noise from p-type point contact germanium detector signals

“…This is of direct relevance to experiments using germanium detectors to search for rare-events at low energies, such as solar axions, violation of the Pauli Exclusion Principle, and electron decay [10]. A reduction in noise would also allow for better background rejection techniques that are based on pulse shapes, such as the rejection of slow energy-degraded pulses in germanium detectors searching for signals at low energies [11,12].…”

Search for solar axions via axion-photon coupling with the Majorana Demonstrator

“…Charge carriers diffuse out of the transition layer slowly, resulting in pulses with slower risetime and degraded energy. A novel data analysis method was recently developed to reject these slow pulses at low energy in the Demonstrator [47,48]. After denoising using a wavelet packet transform and a Daubechies-2 wavelet function, each low energy waveform is fitted with a heuristic exponentially modified Gaussian that generically resembles the waveform and features an effective slowness parameter corresponding to the slope of the pulse rising edge.…”