Usage
  • 6 views
  • 3 downloads

A LIKELIHOOD RATIO ALGORITHM FOR REMOVING LOCALIZED ALPHA PARTICLE BACKGROUNDS IN THE DEAP-3600 DETECTOR

  • Author / Creator
    Mielnichuk, Courtney T.
  • DEAP-3600 (Dark Matter Experiment using Argon for Pulse shape discrimination) is a single phase dark matter experiment using a tonne-scale mass of liquid argon as a target to observe spin-independent interactions with Weakly Interacting Massive Particles (WIMPs). Alpha decays from radioactive nuclei accumulating on the surface of detector materials are a background concern for the experiment. Specifically, alpha decays occurring in the neck region of the detector produce signals with characteristics similar to those expected for WIMP interactions. In order to estimate the potential background from alpha decays in the detector neck, projected material radioactivity levels have been incorporated into Monte Carlo simulations. A likelihood ratio algorithm to discriminate between neck alpha decays and a WIMP signal has been developed based on Monte Carlo simulation. The benefit of implementing a likelihood ratio cut, both in comparison and in combination with a fiducial volume cut, has been studied. Preliminary results of the likelihood ratio applied to commissioning data are also studied.

  • Subjects / Keywords
  • Graduation date
    2017-06:Spring 2017
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/R3BN9XF6T
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Master's
  • Department
    • Department of Physics
  • Supervisor / co-supervisor and their department(s)
    • Hallin, Aksel (Physics)
  • Examining committee members and their departments
    • Grant, Darren (Physics)
    • Kopper, Claudio (Physics)
    • LeBlanc, Lindsay (Physics)