Conveners
RDC 07 Low-Background Detectors Parallel Session
- Daniel Baxter (Fermi National Accelerator Laboratory)
We discovered event-by-event identification of nuclear recoils in silicon from the spatial correlation between the primary ionization event and the defect cluster left behind by the recoiling atom, later identified as a localized excess of leakage current under thermal stimulation. By irradiating a charge-coupled device (CCD) with an AmBe neutron source, we demonstrate full efficiency in the...
High-radiopurity structural materials are needed for a variety of high-energy physics experiments, particularly those involved in the search for dark matter or neutrinoless double beta decay in which background radiation from trace impurities can hide the desired signal. The structural material with the highest radiopurity currently available is electroformed copper, but its yield strength is...
Materials showing exceptionally low content of radioactive impurities and excellent mechanical properties (e.g., yield strength) are needed as structural and shielding materials in current and next-generation low-background detectors. Impurities of naturally occurring radionuclides Th-232, U-238, and their progeny, are typically required to be at or below the microBq/kg range, equating to...
nEXO plans to search for $0\nu\beta\beta$ decay of $^{136}Xe$ with a sensitivity of $1.35\times 10^{28}~\text{yrs}$ using a liquid xenon time projection chamber. The experiment is expected to contain $5000~\text{kg}$ of xenon, and our goal is $< 1.2~\mathrm{mBq}$ $^{222}Rn$ in that system, responsible for 48% of the overall background budget. All xenon wetted components will be assayed to meet...
The discovery of Neutrinoless double beta decay (0νββ) would have profound implicaBons for
neutrino physics and cosmology. It would provide unambiguous evidence for the Majorana
nature of neutrinos, lepton number non-conservaBon and shed light into the absolute neutrino
mass scale. The Large Enriched Germanium Experiment for Neutrinoless ββ decay (LEGEND)
searches for 0νββ in the 76Ge...
For nearly a century, dark matter has been a topic of excited debate and remains an area of active research. Currently, there are three main avenues of dark matter detection: direct detection, indirect detection for example of decay products, or production in particle accelerators. We focus on a specific material that could be used in the first of these. Ice-XI is a hydrogen-ordered phase of...
Long-lived radioactive isotopes produced by cosmogenic activation can be a major source of background for rare event searches such as dark matter and neutrinoless double beta decay. In this talk I will present recent efforts to measure and mitigate cosmogenic tritium production in silicon devices including measurements of the production rate, efforts to reduce exposure through shielding, and...
