Instruments using an “internal” form of this phenomenon are combined with lead tungstate crystals to form the CMS electromagnetic calorimeter. Products of this phenomenon are passed through a microchannel plate in image intensifiers used in night vision goggles. In one common detector, chained dynodes amplify the result (15[1])of this process via secondary emission. This effect dominates at energies lower than those where Compton scattering and (*) pair production are favored. The energy and angle of particles created through this process are used to map electronic band structures in ARPES. Many particle detectors use light produced by scintillators to initiate this process in PMTs, which often contain alkali metals because of their small work function. For 10 points, name this process where light causes the emission (10[1])of electrons from a material. ■END■ (10[1])