Syllabus

VI. Detection of Radiation Images

1. Conversion
1. Radiation input
1. x-ray absorption
2. energy depositon
1. primary events
2. secondary events
3. transport sequences
3. energy deposition probability
1. definition
2. important features
2. Detected Signal
1. Image values
1. energy to charge conversion
2. charge to image value conversion
3. image value vs. exposure
2. charge deposition probability
1. two stage cascades
2. poisson electron statistics
3. convolution results
3. Direct Conversion
1. Charge production (eV per e-h pair
1. bandgap and E per ion pair
2. amorphous materials
2. Recombination time (tau)
3. drift in an electric field (mobility, mu)
4. Charge collection vs voltage
1. Heckt formula
2. mu-tau product
5. Leakage current
1. Resistivity
2. Effect on signal noise
6. PbI2 & CZT examples
4. Indirect Conversion
1. The scintillation process
1. excitation
2. electron-hole pair transport
3. trapping centers
4. prompt luminescence
5. stimulated emission
6. radiation cascade process
2. Inorganic scintillator materials
1. materials types
• granular
• ceramic
• oriented needles
• solid
2. materials properties
• Density & effective Z
• Hygroscopicity
• Light yield, Photons/MeV
• Decay time
• Emission wavelength spectra
• Stimulated Emission spectra
3. photodetection
1. Photomultipier tube arrays
2. Photodiode arrays
• CCD
• a-Si TFT array
3. Indirect conversion efficiency
4. electron signal deposition probability
1. solid detector spectra
2. thin screen CsI spectra
3. granular screen spectra