Skipping to the Finish Line: Sub-Electron Resolution Measurements with DAMIC-M CCDs for Dark Matter Detection

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A90263%2F24%3A00381561" target="_blank" >RIV/68407700:90263/24:00381561 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.6082/uchicago.13992" target="_blank" >https://doi.org/10.6082/uchicago.13992</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Skipping to the Finish Line: Sub-Electron Resolution Measurements with DAMIC-M CCDs for Dark Matter Detection

Original language description

Dark matter constitutes ~ 27% of the matter-energy distribution in the Universe. Over the past several decades, low-background experiments have been built at underground facilities to search for direct interactions with the elusive particle(s). In order to detect rare signals from dark matter interactions, great efforts must be taken to reduce, characterize, or model the natural radiation backgrounds in the laboratory environment. Detectors that are sensitive to electron and neutron scatters are subject to interactions from gamma rays and neutrons that originate from radioactive decays in nearby materials. Interactions in the detector from these particles can mimic dark matter interactions, so their signal needs to be precisely characterized. In this thesis, I present my contributions towards the research and development efforts for the DAMIC-M experiment. Two dedicated measurements were conducted at the University of Chicago campus with silicon skipper CCDs; whose floating gate amplifier allows for multiple Non-Destructive Charge Measurements (NDCMs) to reduce a pixel’s readout noise to a sub-electron level. The first measurement exposed the detector to gamma rays from an Am-241 source. The resultant Compton spectrum demonstrated clear features of silicon’s atomic shells and measured for the first time a clear signature of the L1 - L2,3 atomic shells and scattering off of valence-shell electrons. This measurement successfully demonstrated the efficacy of skipper technology (in contrast to conventional CCDs) by pushing the measurement threshold to 23 eV with only 64 NDCMs. The second measurement exposed the detector to an antimony-beryllium photo-neutron source to measure the ionization efficiency of silicon from nuclear scatters. This measurement demonstrates the full power of skipper technology’s ability to resolve single electrons and measures the ionization yield down to an O(eV) of charge-ionization. These two measurements demonstrate the sensitivity of DAMIC-M detectors to dark matter interactions with silicon electrons or nuclei.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

10304 - Nuclear physics

Project

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Continuities

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Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů