A self-scanned photodiode array was fiber-optically coupled to an ITT proximity-focused image intensifier tube. It was determined that a single photoelectron event produces 3.4 × 104 charge carriers in a photodiode. This charge is only a factor of 2.8 above the rms noise level of the preamplifier used in the tests, but standard charge-sensitive techniques are at least a factor of 12 better. The image tube and photodiode array combination can be packaged in a disk 5.1 cm in diameter and 2.6 cm thick.
Bill R. Sandel and A. Lyle Broadfoot, "Photoelectron counting with an image intensifier tube and a self-scanned photodiode array," Appl. Opt. 15, 3111-3114 (1976)