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Title: Proton-induced radiation damage in germanium detectors

Abstract

High-purity germanium (HPGe) detectors will be used in future space missions for gamma-ray measurements and will be subject to interactions with energetic particles. To simulate this process several large-volume n-type HPGe detectors were incrementally exposed to a particle fluence of up to 10{sub 8} protons cm{sup {minus}2} (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation damage. Basic scientific as well as engineering data on detector performance were collected. During the incremental irradiation, the peak shape produced by the detectors showed a significant change from a Gaussian shape to a broad complex structure. After the irradiation all detectors were thoroughly characterized by measuring many parameters. To remove the accumulated radiation damage the detectors were stepwise annealed at temperatures T {le} 110{degrees}C while staying specially designed cryostats. This paper shows that n-type HPGe detectors can be used in charged particles environments as high-energy resolution devices until a certain level of radiation damage is accumulated and that the damage can be removed at moderate annealing temperatures and the detector returned to operating condition.

Authors:
; ;  [1];  [2]; ;  [3];  [4]; ;  [5];  [6]; ;  [7]
  1. (Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut), Mainz (Germany))
  2. (Univ. zu Koln, D-5000 Koln 41 (DE))
  3. (Inst. fur Kernphysik, KFA Julich, D-5170 Julich (DE))
  4. (San Jose State Univ., CA (United States))
  5. (National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center)
  6. (Princeton Gamma-Tech, Princeton, NJ (US))
  7. (Los Alamos National Lab., NM (United States))
Publication Date:
OSTI Identifier:
5090247
Resource Type:
Journal Article
Resource Relation:
Journal Name: IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States); Journal Volume: 38:2
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; HIGH-PURITY GE DETECTORS; ANNEALING; RADIATION EFFECTS; SPACE FLIGHT; IRRADIATION; PROTONS; RESOLUTION; BARYONS; ELEMENTARY PARTICLES; FERMIONS; GE SEMICONDUCTOR DETECTORS; HADRONS; HEAT TREATMENTS; MEASURING INSTRUMENTS; NUCLEONS; RADIATION DETECTORS; SEMICONDUCTOR DETECTORS; 440200* - Radiation Effects on Instrument Components, Instruments, or Electronic Systems

Citation Formats

Bruckner, J., Korfer, M., Wanke, H., Schroeder, A.N.F., Figes, D., Dragovitsch, P., Englert, P.A.J., Starr, R., Trombka, J.I., Taylor, I., Drake, D.M., and Shunk, E.R. Proton-induced radiation damage in germanium detectors. United States: N. p., 1991. Web. doi:10.1109/23.289298.
Bruckner, J., Korfer, M., Wanke, H., Schroeder, A.N.F., Figes, D., Dragovitsch, P., Englert, P.A.J., Starr, R., Trombka, J.I., Taylor, I., Drake, D.M., & Shunk, E.R. Proton-induced radiation damage in germanium detectors. United States. doi:10.1109/23.289298.
Bruckner, J., Korfer, M., Wanke, H., Schroeder, A.N.F., Figes, D., Dragovitsch, P., Englert, P.A.J., Starr, R., Trombka, J.I., Taylor, I., Drake, D.M., and Shunk, E.R. Mon . "Proton-induced radiation damage in germanium detectors". United States. doi:10.1109/23.289298.
@article{osti_5090247,
title = {Proton-induced radiation damage in germanium detectors},
author = {Bruckner, J. and Korfer, M. and Wanke, H. and Schroeder, A.N.F. and Figes, D. and Dragovitsch, P. and Englert, P.A.J. and Starr, R. and Trombka, J.I. and Taylor, I. and Drake, D.M. and Shunk, E.R.},
abstractNote = {High-purity germanium (HPGe) detectors will be used in future space missions for gamma-ray measurements and will be subject to interactions with energetic particles. To simulate this process several large-volume n-type HPGe detectors were incrementally exposed to a particle fluence of up to 10{sub 8} protons cm{sup {minus}2} (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation damage. Basic scientific as well as engineering data on detector performance were collected. During the incremental irradiation, the peak shape produced by the detectors showed a significant change from a Gaussian shape to a broad complex structure. After the irradiation all detectors were thoroughly characterized by measuring many parameters. To remove the accumulated radiation damage the detectors were stepwise annealed at temperatures T {le} 110{degrees}C while staying specially designed cryostats. This paper shows that n-type HPGe detectors can be used in charged particles environments as high-energy resolution devices until a certain level of radiation damage is accumulated and that the damage can be removed at moderate annealing temperatures and the detector returned to operating condition.},
doi = {10.1109/23.289298},
journal = {IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States)},
number = ,
volume = 38:2,
place = {United States},
year = {Mon Apr 01 00:00:00 EST 1991},
month = {Mon Apr 01 00:00:00 EST 1991}
}
  • Excellent energy resolution makes germanium detectors prime candidates for gamma-ray spectroscopy in space missions. The authors present a study of several large-volume n-type and p-type high purity germanium (HPGe) detectors that were damaged by 1.5 GeV protons and examine their performance as function of fluence, operating and anneal temperature, and time. N-type detectors exhibit essential advantages for space applications over p-type detectors. Annealing at about 110 K for both detector types was observed as well as resolution transients up to 134 K. They discuss the observed radiation effects with respect to existing models and show their limitations.
  • High-purity germanium detectors containing differing concentrations of (H/sub 2/), (Si) and (O/sub 2/) have been irradiated with fast neutrons from a /sup 238/Pu /sup 9/Be source (average energy 4.2 MeV). Measurements of the full width at half maximum (FWHM) resolution of the 1.17 MeV /sup 60/Co photopeak have been carried out as a function of neutron flux, electric field, time after application of bias and detector thickness.
  • Motivated by their applicability to gamma-ray spectroscopy experiments in space, quantitative studies of radiation damage effects in high-purity germanium detectors due to high-energy charged particles have been initiated with the irradiation by 6 GeV/c protons of two 1.0 cm thick planar detectors maintained at 88/sup 0/K. The threshold for resolution degradation and the annealing characteristics differs markedly from those previously observed for detectors irradiated by fast neutrons. Under proton bombardment, degradation in the energy resolution was found to begin below 7 x 10/sup 7/ protons/cm/sup 2/, and increased proportionately in both detectors until the experiment was terminated at a totalmore » flux of 5.7 x 10/sup 8/ protons/cm/sup 2/, equivalent to about a six year exposure to cosmic-ray protons in space. At the end of the irradiation, the FWHM resolution measured at 1332 keV stood at 8.5 and 13.6 keV, with both detectors of only marginal utility as a spectrometer due to the severe tailing caused by charge trapping. The two detectors displayed a significant difference in proton damage sensitivity, which is consistent with fast neutron damage effects. To ensure that detector variability did not influence the comparison of proton- and neutron-induced damage effects, one of the detectors had been used previously in a neutron damage experiment. The threshold for high-energy proton damage was found to be markedly lower, roughly 5 x 10/sup 7/ protons/cm/sup 2/, compared to 3 x 10/sup 9/ neutrons/cm/sup 2/ for fast neutrons. Annealing these detectors after proton damage was found to be much easier than after neutron damage. A satisfactory level of recovery after high-energy proton damage can be achieved with in-situ annealing in the range of 100/sup 0/C.« less
  • The motivation for investigating the use of GaAs as a material for detecting particles in experiments for high-energy physics (HEP) arose from its perceived resistance to radiation damage. This is a vital requirement for detector materials that are to be used in experiments at future accelerators where the radiation environments would exclude all but the most radiation resistant of detector types.