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Title: Dedicated Searches for Low and High Mass Wimps with the SuperCDMS Soudan iZIP Detectors

Abstract

Recent cosmological evidence suggests most of the mass of the universe takes the form of a type of particle that we have not been able to directly detect. Nearly 80 years that have elapsed since the rst hints of this dark matter started to appear from astronomers without any direct detection. The high precision era of cosmology and unifying models of particle physics developed in the 20 th century have presented us with an exciting mystery at the intersection of these two elds that needs to be solved. SuperCDMS Soudan operates specialized germanium detectors (iZIPs) that are cooled to milliKelvin temperatures deep underground in the Soudan Underground Laboratory with the hope of detecting a rare collision between dark matter and a nucleus. A search for low-mass dark matter comes with multiple unique challenges since the background discrimination abilities of these detectors becomes less powerful at the low energies needed to probe low-mass dark matter since the signal to noise ratio deteriorates. Using a sophisticated background model via a pulse rescaling technique, SuperCDMS Soudan was able to produce a world leading exclusion limit on low-mass dark matter. Effort is to extend the analysis to higher masses require long running times duringmore » which many aspects of the detectors or the environment can change. Additional challenges are offered by the powerful background discrimination ability of the iZIP. The background distributions are well separated from the signal region, meaning most of the leakage arises from low-probability tails of the background distributions. In the absence of an enormous dataset, extrapolations from the bulk of the distribution are required. While attempting to obtain a model of gamma induced electron-recoils leaking into the signal region of the detector from high radius a curious asymmetry between the sides of the detectors was discovered potentially indicating an electronics or detector design problem. This thesis describes the physics behind SuperCDMS Soudan, the numerous tasks involved in a low-mass search and the rst iZIP array science results with these new detectors, as well as the developments towards a high-mass search result.« less

Authors:
 [1]
  1. Florida State Univ., Tallahassee, FL (United States)
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1350525
Report Number(s):
FERMILAB-THESIS-2016-37
1452732
DOE Contract Number:  
AC02-07CH11359
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Welliver, Bradford. Dedicated Searches for Low and High Mass Wimps with the SuperCDMS Soudan iZIP Detectors. United States: N. p., 2016. Web. doi:10.2172/1350525.
Welliver, Bradford. Dedicated Searches for Low and High Mass Wimps with the SuperCDMS Soudan iZIP Detectors. United States. doi:10.2172/1350525.
Welliver, Bradford. Fri . "Dedicated Searches for Low and High Mass Wimps with the SuperCDMS Soudan iZIP Detectors". United States. doi:10.2172/1350525. https://www.osti.gov/servlets/purl/1350525.
@article{osti_1350525,
title = {Dedicated Searches for Low and High Mass Wimps with the SuperCDMS Soudan iZIP Detectors},
author = {Welliver, Bradford},
abstractNote = {Recent cosmological evidence suggests most of the mass of the universe takes the form of a type of particle that we have not been able to directly detect. Nearly 80 years that have elapsed since the rst hints of this dark matter started to appear from astronomers without any direct detection. The high precision era of cosmology and unifying models of particle physics developed in the 20 th century have presented us with an exciting mystery at the intersection of these two elds that needs to be solved. SuperCDMS Soudan operates specialized germanium detectors (iZIPs) that are cooled to milliKelvin temperatures deep underground in the Soudan Underground Laboratory with the hope of detecting a rare collision between dark matter and a nucleus. A search for low-mass dark matter comes with multiple unique challenges since the background discrimination abilities of these detectors becomes less powerful at the low energies needed to probe low-mass dark matter since the signal to noise ratio deteriorates. Using a sophisticated background model via a pulse rescaling technique, SuperCDMS Soudan was able to produce a world leading exclusion limit on low-mass dark matter. Effort is to extend the analysis to higher masses require long running times during which many aspects of the detectors or the environment can change. Additional challenges are offered by the powerful background discrimination ability of the iZIP. The background distributions are well separated from the signal region, meaning most of the leakage arises from low-probability tails of the background distributions. In the absence of an enormous dataset, extrapolations from the bulk of the distribution are required. While attempting to obtain a model of gamma induced electron-recoils leaking into the signal region of the detector from high radius a curious asymmetry between the sides of the detectors was discovered potentially indicating an electronics or detector design problem. This thesis describes the physics behind SuperCDMS Soudan, the numerous tasks involved in a low-mass search and the rst iZIP array science results with these new detectors, as well as the developments towards a high-mass search result.},
doi = {10.2172/1350525},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2016},
month = {1}
}

Thesis/Dissertation:
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