The processing of enriched germanium for the Majorana Demonstrator and R&D for a next generation double-beta decay experiment
The Majorana Demonstrator is an array of point-contact Ge detectors fabricated from Ge isotopically enriched to 88% in to search for neutrinoless double beta decay. The processing of Ge for germanium detectors is a well-known technology. However, because of the high cost of Ge enriched in special procedures were required to maximize the yield of detector mass and to minimize exposure to cosmic rays. These procedures include careful accounting for the material; shielding it to reduce cosmogenic generation of radioactive isotopes; and development of special reprocessing techniques for contaminated solid germanium, shavings, grindings, acid etchant and cutting fluids from detector fabrication. Processing procedures were developed that resulted in a total yield in detector mass of 70%. However, none of the acid-etch solution and only 50% of the cutting fluids from detector fabrication were reprocessed. Had they been processed, the projections for the recovery yield would be between 80% and 85%. Maximizing yield is critical to justify a possible future ton-scale experiment. A process for recovery of germanium from the acid-etch solution was developed with yield of about 90%. All material was shielded or stored underground whenever possible to minimize the formation of 68Ge by cosmic rays, which contributes background in the double-beta decay region of interest and cannot be removed by zone refinement and crystal growth. Formation of 68Ge was reduced by a significant factor over that in natural abundance detectors not protected from cosmic rays.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP); National Science Foundation (NSF); Russian Foundation for Basic Research
- Contributing Organization:
- Majorana Collaboration; GERDA Collaboration
- Grant/Contract Number:
- AC52-06NA25396; AC05-76RL01830; AC02-05CH11231; FG02-97ER41041; FG02-97ER41033; FG02-97ER41042,; SC0012612; FG02-10ER41715; SC0010254; FG02-97ER41020; PHY-0919270, PHY-1003940, PHY-0855314; PHY-1202950; MRI 0923142; PHY-1307204; PHY-1003399; 15-02-02919; AC05-00OR22725
- OSTI ID:
- 1402099
- Alternate ID(s):
- OSTI ID: 1402647; OSTI ID: 1413485; OSTI ID: 1419471; OSTI ID: 1454382
- Report Number(s):
- LA-UR-17-26439; PNNL-SA-123765; S0168900217310069; PII: S0168900217310069
- Journal Information:
- Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Journal Name: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment Vol. 877 Journal Issue: C; ISSN 0168-9002
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- Netherlands
- Language:
- English
Web of Science
Similar Records
Search for Neutrinoless Double- Decay in with the Majorana Demonstrator
Search for Pauli exclusion principle violating atomic transitions and electron decay with a p-type point contact germanium detector