scintillator (fluorescent substance)

The scintillator is a substance that emits fluorescence by absorbing the energy of an electron beam or electromagnetic wave. A fluorescent substance for the "scintillator" is selected by taking account of the fluorescence wavelength (color) and its persistence time according to the sensitivity characteristic of a photoelectric converter placed behind the scintillator. The scintillator is used for various purposes: a fluorescent screen (yellow-green light, persistence light: ～100 ms) to visualize a TEM image, a secondary-electron detector (blue light, persistence light: ～μs) to measure the beam intensity of secondary electrons, and a TEM image detector (YAG) (blue white light, persistence light: ～μs) placed before a CCD.