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Physics and Astronomy PhD Defense – Sam Meijer

June 3, 2019 @ 11:00 am - 1:00 pm

UNC-CH Physics and Astronomy PhD Defense

Sam Meijer

“Precision Modeling of Germanium Detector Waveforms For Rare Event Searches”

Neutrinoless double-beta decay is a proposed rare nuclear event. Current generation experiments require high sensitivity designs, with the ability to remove background signals. The MAJORANA DEMONSTRATOR is a neutrinoless double-beta decay experiment using high purity p-type point contact germanium detectors. The waveforms produced by these detectors have subtle variation indicating the detailed energy and drift path information for each event. In addition, the waveforms depend sensitively on crystal impurity levels, temperature, and operating voltage. We have developed a machine learning algorithm which, given a set of calibration waveforms, can infer detector parameters. Once these parameters are known, a precision detector model can be used to fit the drift paths of individual waveforms. This method can be used for parameter estimation, and as a sensitive background rejection technique for the DEMONSTRATOR or the proposed future LEGEND experiment. Design, performance, applications, and future plans will be discussed.

Details

Date:
June 3, 2019
Time:
11:00 am - 1:00 pm

Venue

Chapman 435