A general solution to the positive ion feedback problem in Hybrid Photon De
tectors (HPD), photomultipliers and other similar detectors was found in th
e insertion of a permanent electrostatic potential barrier which prevents d
rift of positive ions from the anode, or the first dynode, towards the phot
ocathode. In this paper, we present the method as applied to the Intevac HP
D. (C) 1999 Elsevier Science B.V. All rights reserved.