Collaborative Research: Maximizing Background Rejection in SuperCDMS Dark Matter Detectors

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The nature of dark matter is one of the most important research topics in physics today. It pertains to fundamental unanswered questions in particle physics, astrophysics, and cosmology. A possible candidate for dark matter is a Weakly Interacting Massive Particle (WIMP). The goal of the Cryogenic Dark matter Search (CDMS) experiment is to develop a detector that has the sensitivity to observe such WIMPs if they exist. The research objective of this project is to improve the background rejection of current and future SuperCDMS detectors by means of significantly improved energy, position, and timing determination. This work will make important contributions to both the current SuperCDMS experiment at Soudan and the design and successful operation of the collaboration's next-generation, 5 kg detectors for a future 100 kg experiment and beyond through the following tasks: i) Development of SuperCDMS detector models from first principles. The PI will model the time structure of the phonon pulses as a function of position, energy, and recoil type to understand the source of discrepancies between their current models and data; and ii) Development of a novel detector characterization and calibration facility to measure phonon pulse shapes and ionization response as a function of event energy, position, and recoil type. This unique mapping of detector response will be used to refine the detector simulation described above as well as provide an exhaustive, empirical data set for defining the background rejection analyses. The broader impact of the program includes training graduate students and postdoctoral researchers in experimental physics. The technology and methods developed have direct applications in neutrino and X-ray astrophysics as well as broader applications in superconducting detectors with uses in material science and nuclear isotope identification.