The transference of the light photons to the photocathode. The absorption of the photons at the photocathode and the emission of the photoelectrons. Electron-multiplication process within the photomultiplier. Figure 2 offers a visual representation of these six steps. Electron produced in scintillator .
Light travels through light pipe, to the photocathode.
Secondary electrons produced within photocathode. Secondary electrons go to the photo-multiplier tube. The output of a detector is called a pulse-height spectrum. Figures 3 and 4 offers a comparison of sprectra from two different detectors with the same source. Both spectra represent the collection of 1.37 and 2.75 MeV gamma rays emitted from Sodium-24.