GeMSE: a low-background facility for gamma-spectrometry at moderate rock overburden

Ramírez García, D.; Baur, D.; Grigat, J.; Hofmann, B.A.; Lindemann, S.; Masson, D.; Schumann, M.; von Sivers, M.; Toschi, F. (2022). GeMSE: a low-background facility for gamma-spectrometry at moderate rock overburden. Journal of instrumentation, 17(04), P04005. Institute of Physics Publishing IOP 10.1088/1748-0221/17/04/P04005

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The GeMSE (Germanium Material and meteorite Screening Experiment) facility operates a low-background HPGe crystal in an underground laboratory with a moderate rock overburden of 620 m.w.e. in Switzerland. It has been optimized for continuous remote operation. A multi-layer passive shielding, a muon veto, and a boil-off nitrogen purge line inside the measurement cavity minimize the instrument's background rate, which decreased by 33% to (164 ± 2) counts/day (100 – 2700 keV) after five years of underground operation. This agrees with the prediction based on the expected decay of short-lived isotopes. A fit to the known background components, modeled via a precise simulation of the detector, shows that the GeMSE background is now muon-dominated. We also present updates towards a more accurate detection efficiency calculation for the screened samples: the thickness of the crystal's outer dead-layer is precisely determined and the efficiency can now be easily calculated for any sample geometry. The advantage of this feature is showcased via the determination of the 40K content in the screening of a complex-shaped object: a banana.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)
08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Hofmann, Beda Anton, Schumann, Marc

Subjects:

500 Science > 530 Physics
500 Science > 550 Earth sciences & geology

ISSN:

1748-0221

Publisher:

Institute of Physics Publishing IOP

Funders:

[42] Schweizerischer Nationalfonds

Language:

English

Submitter:

Beda Anton Hofmann

Date Deposited:

23 Mar 2023 12:39

Last Modified:

26 Mar 2023 03:16

Publisher DOI:

10.1088/1748-0221/17/04/P04005

BORIS DOI:

10.48350/180546

URI:

https://boris.unibe.ch/id/eprint/180546

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