Radiation Damage to Semiconductor Detectors

The fabrication and operation of a semiconductor detector are based on the premise that one starts with a perfect crystal containing a known amount of impurities. Even if this is true at the beginning, a semiconductor detector will suffer damage after being exposed to radiation. The principal type of radiation damage is caused by the collision of an incident particle with an atom. As a result of the collision, the atom may be displaced into an interstitial position, thus creating an interstitial-vacancy pair known as the Frenkel defect. A recoiling 

Material Atomic number Energy gap (eV) Energy needed to form the pair (eV) 

Ge detectors are not affected by gammas, but they are damaged by the neutrons in a mixed n-y field. 

1 What is the probability that an electron energy state in Ge will be occupied at temperature T = 300 K if the energy state is greater than the Fermi energy by 2 eV  

3 The energy gap for diamond is 7 eV. What temperature will provide thermal energy (kT) equal to that amount  

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