Abstract
The Super Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory studied energy loss associated with defect formation in germanium crystals at mK temperatures using in situ 210Pb sources. We examine the spectrum of 206Pb nuclear recoils near its expected 103 keV endpoint energy and determine an energy loss of (6:08 ± 0:18)%, which we attribute to defect formation. From this result and using TRIM simulations, we extract the first experimentally determined average displacement threshold energy of 19.7-0.5+0.6 eV for germanium. This has implications for the analysis thresholds of future germanium-based dark matter searches.
Original language | English (US) |
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Article number | 092101 |
Journal | Applied Physics Letters |
Volume | 113 |
Issue number | 9 |
DOIs | |
State | Published - Aug 27 2018 |
Bibliographical note
Funding Information:SLAC is operated under Contract No. DEAC02-76SF00515 with the U.S. Department of Energy.
Funding Information:
The SuperCDMS collaboration gratefully acknowledges technical assistance from the staff of the Soudan Underground Laboratory and the Minnesota Department of Natural Resources. The iZIP detectors were fabricated in the Stanford Nanofabrication Facility, which is a member of the National Nanofabrication Infrastructure Network, sponsored and supported by the NSF. We would like to thank Franc¸ois Schiettekatte for his feedback in reviewing an early manuscript. Funding and support were received from the National Science Foundation, the U.S. Department of Energy, Fermilab URA Visiting Scholar Grant No. 15-S-33, NSERC Canada, the Canada First Research Excellence Fund, and MultiDark (Spanish MINECO). This document was prepared by the SuperCDMS collaboration using the resources of the Fermi National Accelerator Laboratory (Fermilab), a U.S. Department of Energy, Office of Science, HEP User Facility. Fermilab is managed by Fermi Research Alliance, LLC (FRA), acting under Contract No. DE-AC02-07CH11359. Pacific Northwest National Laboratory is operated by Battelle Memorial Institute under Contract No. DE-AC05-76RL01830 for the U.S. Department of Energy.
Funding Information:
and support were received from the National Science Foundation, the U.S. Department of Energy, Fermilab URA Visiting Scholar Grant No. 15-S-33, NSERC Canada, the Canada First Research Excellence Fund, and MultiDark (Spanish MINECO). This document was prepared by the SuperCDMS collaboration using the resources of the Fermi National Accelerator Laboratory (Fermilab), a U.S. Department of Energy, Office of Science, HEP User Facility. Fermilab is managed by Fermi Research Alliance, LLC (FRA), acting under Contract No. DE-AC02-07CH11359. Pacific Northwest National Laboratory is operated by Battelle Memorial Institute under Contract No. DE-AC05-76RL01830 for the U.S. Department of Energy. SLAC is operated under Contract No. DEAC02-76SF00515 with the U.S. Department of Energy.
Publisher Copyright:
© 2018 Author(s).