Fano Factor in Germanium at 77°K

Abstract

The Fano factor in germanium at liquid-nitrogen temperature has been found to be F = 0.129±0.003 using 7 rays at energies from 0.122 to 4.8 MeV. F appears to be independent of the primary energy in the investigated energy range. Care has been exercised to eliminate the influence of ballistic deficit, recombination, and trapping in planar lithium-drifted structures as well as noise, drift, and pile-up in the apparatus. Measurements with crystals having volumes from 0.8 to 13 cm gave consistent results. We examined the line shift and the linewidth dependence up to and into electric field strengths where saturation of electron and hole velocities occurs.

Signal variance in gamma-ray detectors—A review

“…2. By neglecting phonon production and assuming all transitions from the valence band to the conduction band to be equally probable, Bilger [8] obtained for m-N, n-N F ¼ 1 3…”

“…The ultimate energy resolution of the material [8] in the absence of variance due to signal transfer and collection processes is…”

“…Thus the variance in the number of charge carriers is properly expressed according to Fano [7] as where the Fano factor F has a value between zero and unity. The resulting spectroscopic root-mean-square line width is given by [8] s ¼ ðWFEÞ 1=2 .…”

“…Bilger [8] determined the limiting values of F in a semiconductor using a simple model that considered a band gap E g between a valence band of width bE g containing m equidistant energy levels and a conduction band of width aE g with n such levels as shown in Fig. 2.…”

Preparation and characterization of (CuInSe2)1−x(CoSe)x alloys in the composition range 0 ≤ x ≤ 2/3

“…The term (2.35 2 Fe) comes from the electron-hole creation statistics. F is the Fano factor, which takes account of the fact that the statistics are not exactly of the Poisson type, suggesting a different process is implicated in the electron-hole creation mechanism, and it has a value near to 0.1 for Ge detectors at 77 K [17][18][19]; e is related to the free carriers created in the process and …”