Physics and Engineering of Radiation Detection

256 Chapter 5. Solid State Detectors Si Si Si Si Si Si Si Si Si Si Si Si Si Si Si Covalent Bond Energy (a) (b) Valence Band Cond ...

5.1. Semiconductor Detectors 257 The underlying physical processes involved in the creation of electron-hole pairs in semiconduc ...

258 Chapter 5. Solid State Detectors Eimp Eg Radiation Incident Valence Band E Conduction Band Electron Hole Figure 5.1.4: Produ ...

5.1. Semiconductor Detectors 259 where F= x i ( wi i − 1 ) is called theFano factor. It is interesting to note here that even ...

260 Chapter 5. Solid State Detectors E.1 IntrinsicEnergyResolution Equation 5.1.15 gives the observed spread in the number of el ...

5.1. Semiconductor Detectors 261 Example: Determine the energy resolution of a silicon detector for 520keV photons using Fano fa ...

262 Chapter 5. Solid State Detectors which then gets emitted and may even escape from the detector. This emitted electron is cal ...

5.1. Semiconductor Detectors 263 Eg Eimp Hole Electron Conduction Band Valence Band E Photons Figure 5.1.6: Trap-recombination w ...

264 Chapter 5. Solid State Detectors in the material is 10^17 cm^3 and the lifetime of holes at this dopant level is 10μs. Solut ...

5.1. Semiconductor Detectors 265 F.1 DriftofElectronsandHoles.................. The semiconductor detectors are almost always op ...

266 Chapter 5. Solid State Detectors where we have used the relationsρe=eneandρh=enhwithneandnhbeing the number density of elect ...

5.1. Semiconductor Detectors 267 silicon and germanium. This property makes them suitable for operation at room temperature, whi ...

268 Chapter 5. Solid State Detectors EΓ 2 = 4.2 eV EL= 2.0 eV EΓ 1 = 3.4 eV Eg= 1.12 eV EX= 1.2 eV Wavevector Holes Energy Fig ...

5.1. Semiconductor Detectors 269 general practice, still in principle one could operate a detector at room temperature at the ex ...

270 Chapter 5. Solid State Detectors problem since the general practice is to calibrate each detector module separately, which a ...

5.1. Semiconductor Detectors 271 Table 5.1.4: Common donor and acceptor elements used to dope silicon. Also given are their ioni ...

272 Chapter 5. Solid State Detectors and the second is a range of donor density where the effects are most profound. It is appar ...

5.1. Semiconductor Detectors 273 pendence of electron and hole mobilities for silicon can be written as (44) μe ∝ T−^2.^5 (5.1.3 ...

274 Chapter 5. Solid State Detectors Figure 5.1.14: Dependence of hole mo- bility on the donor density in silicon at 300 K(33). ...

5.1. Semiconductor Detectors 275 Now, according to equation 5.1.33, the percentage decrease in intrinsic charge concentration is ...