Four basic components of scintillation detectors.
a) Photomultiplier tube, Scintillator crystal, Light guide, Voltage source
b) Geiger-Mueller tube, Collimator, Crystal scintillator, Photodiode
c) Lead shielding, Detector head, Electronics module, Data display
d) Reflective coating, Photocathode, Photoelectron, Anode