A cryogenic detector with simultaneous phonon and ionization measurement for background rejection

Authors

T. Shutt
Peter D. Barnes Jr.
Alan Cummings
Angela Da Silva
B. Ellman
J. Emes
Y. Giraud-Héraud
Eugene E. Haller
Andrew E. Lange
Ron R. Ross
Bernard Sadoulet
Garth Smith
C. Stubbs
W. Stockwell
N. Wang
S. White
Betty A. Young, Santa Clara UniversityFollow
D. Yvon

Document Type

Article

Publication Date

3-1993

Publisher

Elsevier

Abstract

We report on the performance of a 60 g Ge detector that measures both ionization and phonons at cryogenic (∼ 25 mK) temperatures. This simultaneous measurements is a powerful new tool in experiments where the primary signal is a nuclear recoil (e.g., WIMP dark matter) that must be distinguished from a background of photons or charged particles that produce electron recoils. We have measured nuclear recoils produced by neutrons from a ²⁵²Cf source, and can distinguish them from photons at energies as low as 2 keV in the ionization measurement. An important effect that can limit the efficiency of the background rejection technique is incomplete charge collection. We have tested our detector at ionization drift fields as low as 5 mV/cm and find that the phonon energy measured for each event depends on the amount of charge collected. From this we deduce details about charge trapping mechanisms.

Recommended Citation

Shutt, T., Barnes, P. D., Cummings, A., DaSilva, A., Ellman, B., Emes, J., Giraud-Heraud, Y., Haller, E. E., Lange, A. E., Ross, R. R., Sadoulet, B., Smith, G., Stubbs, C., Stockwell, W., Wang, N., White, S., Young, B. A., & Yvon, D. (1993). A cryogenic detector with simultaneous phonon and ionization measurement for background rejection. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 326(1), 166–171. https://doi.org/10.1016/0168-9002(93)90347-K