May 19 – 23, 2019

## Measuring cosmogenic activation rates in active detector material

Not scheduled
20m

Richard Saldanha

### Description

Long-lived radioactive isotopes produced by cosmogenic activation are a major source of background for rare event searches such as dark matter and neutrinoless double beta decay. Understanding the production rates of these cosmogenic isotopes is extremely important for determining the total allowable surface residence time of detector materials during fabrication, storage, and transportation. However, experimentally measuring the production rate is difficult due to low specific activities and because several of the decays of interest produce low energy electrons and x-rays that are not easily detectable. I will discuss a measurement technique that uses a high intensity neutron beam (with a spectrum similar to cosmic ray neutrons) in conjunction with low-background self-counting methods to determine production rates in active detector materials. Based on this technique I will present results from the first experimental measurement of $^{39}$Ar and $^{37}$Ar cosmogenic production rates in argon, ongoing work on the first measurement of cosmogenic tritium production in silicon, and possible applications to other detector materials.

### Co-authors

Alexander Piers (University of Washington) Alvaro Chavarria (University of Washington) Ariel Matalon (University of Chicago) Emily Mace (Pacific Northwest National Laboratory) Henning Back (Pacific Northwest National Laboratory) Karthik Ramanathan (University of Chicago) Paolo Privitera (University of Chicago) Pitam Mitra (University of Alberta) Raymond Bunker (Pacific Northwest National Laboratory) Raymond Hei-Man Tsang (Pacific Northwest National Laboratory) Ryan Thomas (University of Chicago) Dr Steven Elliott (Los Alamos National Laboratory) Thomas Alexander (Pacific Northwest National Laboratory)

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