The Processing of Enriched Germanium for the MAJORANA DEMONSTRATOR and R&amp;D for a Possible Future Ton-Scale Ge-76 Double-Beta Decay Experiment
Creators: name: Abgrall, N.
name: Arnquist, I. J.
name: Avignone, F. T.
name: Barabash, A. S.
name: Bertrand, F. E.
name: Bradley, A. W.
name: Brudanin, V.
name: Busch, M.
name: Buuck, M.
name: Caja, J.
name: Caja, M.
name: Caldwell, T. S.
name: Christofferson, C. D.
name: Chu, P. -H.
name: Cuesta, C.
name: Detwiler, J. A.
name: Dunagan, C.
name: Dunstan, D. T.
name: Efremenko, Yu.
name: Ejiri, H.
name: Elliott, S. R.
name: Gilliss, T.
name: Giovanetti, G. K.
name: Goett, J.
name: Green, M. P.
name: Gruszko, J.
name: Guinn, I. S.
name: Guiseppe, V. E.
name: Haufe, C. R. S.
name: Henning, R.
name: Hoppe, E. W.
name: Jasinski, B. R.
name: Kidd, M. F.
name: Konovalov, S. I.
name: Kouzes, R. T.
name: Lopez, A. M.
name: MacMullin, J.
name: Martin, R. D.
name: Massarczyk, R.
name: Meijer, S. J.
name: Mertens, S.
name: Meyer, J. H.
name: Myslik, J.
name: O'Shaughnessy, C.
name: Poon, A. W. P.
name: Radford, D. C.
name: Rager, J.
name: Reine, A. L.
name: Reising, J. A.
name: Rielage, K.
name: Robertson, R. G. H.
name: Shanks, B.
name: Shirchenko, M.
name: Suriano, A. M.
name: Tedeschi, D.
name: Toth, L. M.
name: Trimble, J. E.
name: Varner, R. L.
name: Vasilyev, S.
name: Vetter, K.
name: Vorren, K.
name: White, B. R.
name: Wilkerson, J. F.
name: Wiseman, C.
name: Xu, W.
name: Yakushev, E.
name: Yu, C. -H.
name: Yumatov, V.
name: Zhitnikov, I.
name: Zhu, B. X.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The MAJORANA DEMONSTRATOR is an array of point-contact Ge detectors fabricated from Ge isotopically enriched to 88% in Ge-76 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 Ge-76, 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 -- 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 Ge-68 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 Ge-68 was reduced by a significant factor over that in natural abundance detectors not protected from cosmic rays.
description: Submitted to NIM-A