Electron-Hole Pairs Created by Photons and Intrinsic Properties in Detector Materials

A Monte Carlo (MC) code has been developed to simulate the interaction of gamma-rays with semiconductors and scintillators, and the subsequent energy partitioning of fast electrons. The results provide insights on the processes involved in the electron-hole pair yield and intrinsic variance through simulations of full electron energy cascades. The MC code has been applied to simulate the production of electron-hole pairs and to evaluate intrinsic resolution in a number of semiconductors. In addition, the MC code is also able to consider the spatial distribution of electron-hole pairs induced by photons and electrons in detector materials, and has been employed to obtain details of the spatial distribution of electron-hole pairs in Ge, as a benchmark case. The preliminary results show that the distribution of electron-hole pairs exhibit some important features; (a) the density of electron-hole pairs along the main electron track is very high and (b) most electron-hole pairs produced by interband transitions are distributed at the periphery of the cascade volume. The spatial distribution and density of thermalized electron-hole pairs along the primary and secondary tracks are important for large scale simulations of electron-hole pair transport.

[1]  C. W. Nestor,et al.  Calculation of Electron Shake-Off Probabilities as the Result of X-Ray Photoionization of the Rare Gases , 1973 .

[2]  J. Fernández-Varea,et al.  Semiempirical cross sections for the simulation of the energy loss of electrons and positrons in matter , 1992 .

[3]  Ab initio calculations of inelastic losses and optical constants , 2006, cond-mat/0601241.

[4]  J. H. Hubbell,et al.  XCOM: Photon cross sections on a personal computer , 1987 .

[5]  José M. Fernández-Varea,et al.  Mixed simulation of the multiple elastic scattering of electrons and positrons using partial-wave differential cross-sections , 2001 .

[6]  A. J. Peurrung,et al.  Gamma-ray interaction in Ge: A Monte Carlo simulation , 2007 .

[7]  L Kissel,et al.  EPDL97 The Evaluated Data Library, '97 Version , 1997 .

[8]  F. Scholze,et al.  Mean energy required to produce an electron-hole pair in silicon for photons of energies between 50 and 1500 eV , 1998 .

[9]  J. Barak,et al.  New monte-carlo calculations of charged particle track-structure in silicon , 2004, Proceedings of the 7th European Conference on Radiation and Its Effects on Components and Systems, 2003. RADECS 2003..

[10]  Francesc Salvat,et al.  Elastic scattering of electrons and positrons by atoms. Schrödinger and Dirac partial wave analysis , 1993 .

[11]  Bilger.  THE FANO FACTOR IN GERMANIUM AT 77°K. , 1967 .

[12]  J. Geist.  QUANTUM YIELD OF SILICON NEAR THE LII,III-SHELL ABSORPTION EDGE , 1996 .

[13]  Cross sections for K-shell ionisation by electron impact , 1990 .

[14]  Fei Gao,et al.  Signal variance in gamma-ray detectors-A review , 2006 .

[15]  U. Fano,et al.  On the Theory of Ionization Yield of Radiations in Different Substances , 1946 .

[16]  A. Owens.  Spectral degradation effects in an 86 cm3 Ge(HP) detector , 1985 .

[17]  R. Ribberfors,et al.  X-ray incoherent scattering total cross sections and energy-absorption cross sections by means of simple calculation routines , 1983 .

[18]  Alan A. Wells,et al.  The X-ray energy response of silicon Part A. Theory , 1994 .

[19]  S. Woolf,et al.  ELECTRON-ACOUSTIC PHONON SCATTERING IN SIO2 DETERMINED FROM A PSEUDO-POTENTIAL FOR ENERGIES OF E>EBZ , 1991 .

[20]  Edward L. Garwin,et al.  Electron‐Phonon Interaction in Alkali Halides. I. The Transport of Secondary Electrons with Energies between 0.25 and 7.5 eV , 1969 .

[21]  W. J. Weber,et al.  Monte Carlo method for simulating γ-ray interaction with materials: A case study on Si , 2007 .

[22]  U. Fano.  Ionization Yield of Radiations. II. The Fluctuations of the Number of Ions , 1947 .

[23]  C. Nordling,et al.  Electron escape depth in silicon , 1974 .

[24]  K. Pentek,et al.  Experimental determination of the inelastic mean free path (IMFP) of electrons in Cr, Mo, Ge and Si based on the elastic peak intensity ratio with a Ni reference sample , 1995 .