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Title: Use of the drift-time method to measure the electron lifetime in long-drift-length CdZnTe detectors

The traditional method for electron lifetime measurements of CdZnTe (CZT) detectors relies on using the Hecht equation. The procedure involves measuring the dependence of the detector response on the applied bias to evaluate the μτ product, which in turn can be converted into the carrier lifetime. Despite general acceptance of this technique, which is very convenient for comparative testing of different CZT materials, the assumption of a constant electric field inside a detector is unjustified. In the Hecht equation, this assumption means that the drift time would be a linear function of the distance. This condition is not fulfilled in practice at low applied biases, where the Hecht equation is most sensitive to the μτ product. As a result, researchers usually take measurements at relatively high biases, which work well in the case of the low μτ-product material, <10 -3 cm 2/V, but give significantly underestimated values for the case of high μτ-product crystals. In this paper, we applied the drift-time method to measure the electron lifetimes in long-drift-length (4 cm) standard-grade CZT detectors produced by the Redlen Technologies. We found that the electron μτ product of tested crystals is in the range 0.1–0.2 cm 2/V, which is an ordermore » of the magnitude higher than any value previously reported for a CZT material. Finally, in comparison, using the Hecht equation fitting, we obtained μτ = 2.3 × 10 -2 cm 2/V for a 2-mm thin planar detector fabricated from the same CZT material.« less
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [1] ;  [1] ;  [2] ;  [4] ;  [5] ;  [2] ;  [1] ;  [1] ; ORCiD logo [2] ;  [6]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Redlen Technologies, Saanichton, BC (Canada)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States); Charles Univ., Prague (Czech Republic). Inst. of Physics
  4. Brookhaven National Lab. (BNL), Upton, NY (United States); Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering
  5. Univ. of Surrey, Guildford (United Kingdom). Dept. of Physics
  6. Brookhaven National Lab. (BNL), Upton, NY (United States); Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL). Science and Technology Directorate
Publication Date:
Report Number(s):
BNL-207826-2018-JAAM
Journal ID: ISSN 0021-8979
Grant/Contract Number:
SC0012704
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 120; Journal Issue: 10; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation (NA-20)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; time measurement; electron mobility; position sensitive detectors; electrical sensors; anodes; cathodes; amplifiers; electric fields; electric measurements; ballistics
OSTI Identifier:
1460686

Bolotnikov, A. E., Camarda, G. S., Chen, E., Gul, R., Dedic, V., De Geronimo, G., Fried, J., Hossain, A., MacKenzie, J. M., Ocampo, L., Sellin, P., Taherion, S., Vernon, E., Yang, G., El-Hanany, U., and James, R. B.. Use of the drift-time method to measure the electron lifetime in long-drift-length CdZnTe detectors. United States: N. p., Web. doi:10.1063/1.4962540.
Bolotnikov, A. E., Camarda, G. S., Chen, E., Gul, R., Dedic, V., De Geronimo, G., Fried, J., Hossain, A., MacKenzie, J. M., Ocampo, L., Sellin, P., Taherion, S., Vernon, E., Yang, G., El-Hanany, U., & James, R. B.. Use of the drift-time method to measure the electron lifetime in long-drift-length CdZnTe detectors. United States. doi:10.1063/1.4962540.
Bolotnikov, A. E., Camarda, G. S., Chen, E., Gul, R., Dedic, V., De Geronimo, G., Fried, J., Hossain, A., MacKenzie, J. M., Ocampo, L., Sellin, P., Taherion, S., Vernon, E., Yang, G., El-Hanany, U., and James, R. B.. 2016. "Use of the drift-time method to measure the electron lifetime in long-drift-length CdZnTe detectors". United States. doi:10.1063/1.4962540. https://www.osti.gov/servlets/purl/1460686.
@article{osti_1460686,
title = {Use of the drift-time method to measure the electron lifetime in long-drift-length CdZnTe detectors},
author = {Bolotnikov, A. E. and Camarda, G. S. and Chen, E. and Gul, R. and Dedic, V. and De Geronimo, G. and Fried, J. and Hossain, A. and MacKenzie, J. M. and Ocampo, L. and Sellin, P. and Taherion, S. and Vernon, E. and Yang, G. and El-Hanany, U. and James, R. B.},
abstractNote = {The traditional method for electron lifetime measurements of CdZnTe (CZT) detectors relies on using the Hecht equation. The procedure involves measuring the dependence of the detector response on the applied bias to evaluate the μτ product, which in turn can be converted into the carrier lifetime. Despite general acceptance of this technique, which is very convenient for comparative testing of different CZT materials, the assumption of a constant electric field inside a detector is unjustified. In the Hecht equation, this assumption means that the drift time would be a linear function of the distance. This condition is not fulfilled in practice at low applied biases, where the Hecht equation is most sensitive to the μτ product. As a result, researchers usually take measurements at relatively high biases, which work well in the case of the low μτ-product material, <10-3 cm2/V, but give significantly underestimated values for the case of high μτ-product crystals. In this paper, we applied the drift-time method to measure the electron lifetimes in long-drift-length (4 cm) standard-grade CZT detectors produced by the Redlen Technologies. We found that the electron μτ product of tested crystals is in the range 0.1–0.2 cm2/V, which is an order of the magnitude higher than any value previously reported for a CZT material. Finally, in comparison, using the Hecht equation fitting, we obtained μτ = 2.3 × 10-2 cm2/V for a 2-mm thin planar detector fabricated from the same CZT material.},
doi = {10.1063/1.4962540},
journal = {Journal of Applied Physics},
number = 10,
volume = 120,
place = {United States},
year = {2016},
month = {9}
}