Comparison of CDMS [100] and [111] oriented germanium detectors

S. W. Leman*, S. A. Hertel, P. Kim, B. Cabrera, E. Do Couto E Silva, E. Figueroa-Feliciano, K. A. McCarthy, R. Resch, B. Sadoulet, K. M. Sundqvist

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The Cryogenic DarkMatter Search (CDMS) utilizes large mass, 3'' diameter × 1'' thick target masses as particle detectors. The target is instrumented with both phonon and ionization sensors and comparison of energy in each channel provides event-by-event classification of electron and nuclear recoils. Fiducial volume is determined by the ability to obtain good phonon and ionization signal at a particular location. Due to electronic band structure in germanium, electron mass is described by an anisotropic tensor with heavy mass aligned along the symmetry axis defined by the [111] Miller index (L valley), resulting in large lateral component to the transport. The spatial distribution of electrons varies significantly for detectors which have their longitudinal axis orientations described by either the [100] or [111] Miller indices. Electric fields with large fringing component at high detector radius also affect the spatial distribution of electrons and holes. Both effects are studied in a 3 dimensional Monte Carlo and the impact on fiducial volume is discussed.

Original languageEnglish (US)
Pages (from-to)1106-1111
Number of pages6
JournalJournal of Low Temperature Physics
Issue number5-6
StatePublished - Jun 2012


  • Charge transport
  • Cryogenic
  • Dark matter search
  • Germanium

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics


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