An improved apparatus is described for examining the numbers of electrons produced in elementary acts of field emission. Multiple acts of emission related to parasitic secondary effects are not recorded. The field-emission image is visualized. A probe system is used with a mobile cathode unit to make measurements on different crystallographic planes of a single crystal. A surface-barrier gold-silicon detector records electrons of energy 10 kev with a resolution of 2. 8 kev. The working pulse length in the spectrometer is 5 mu sec and the average count rate is approximately 500 count/sec, and the sensitivity in observing double acts of emission is approximately 0. 1%.