8:00–9:00 am
Ariel Matalon’s PhD Thesis Defense
Ariel’s thesis defense is for the first-ever international dual-PhD in physics from the University of Chicago, awarded jointly with Sorbonne Université in Paris.
Searching for Light Dark Matter with DAMIC at SNOLAB and DAMIC-M: Investigations into Radioactive Backgrounds and Silicon Skipper Charge-Coupled Devices
The DAMIC (Dark Matter in CCDs) program employs the bulk silicon of scientific CCDs to search for ionization signals produced by interactions of particle dark matter, the nature of which is still unknown. By virtue of the low noise, low leakage current, and exquisite spatial resolution of DAMIC CCDs, as well as the relatively low mass of the silicon nucleus, DAMIC is sensitive to ionization signals from recoiling nuclei or electrons following the scattering of WIMP or hidden-sector dark matter particles.
The theme of this thesis is to advance next-generation CCD dark matter searches by investigating radioactive backgrounds that limit sensitivity and by improving the resolution of CCDs using Skipper technology. I present a technique to distinguish and reject background events in the DAMIC at SNOLAB detector by identifying spatially-correlated decay sequences over long periods. I also discuss a direct experimental measurement of the cosmogenic activation of silicon, obtained via CCD irradiation. I review the construction of a radioactive background model for a CCD dark matter detector, which revealed the existence of a partial charge collection region in DAMIC CCDs. I propose steps for optimal fabrication and handling of future detectors.
Finally, I outline results from the deployment of novel Skipper CCDs that reach sub-electron resolution by performing non-destructive, multiple measurements of pixel charge. DAMIC-M, a kg-size Skipper CCD experiment, is being developed. I review the construction of automated test chambers to characterize DAMIC-M prototype CCDs, for which a detector resolution of 0.07 e- has already been demonstrated.
Committee Members:
Paolo Privitera (Chair)
Abigail Vieregg
Robert Rosner
David Awschalom
Ariel will be an Associate at McKinsey & Company’s New York office