We have designed and operated a multistep avalanche chamber capable of detecting single photons in the vacuum ultraviolet wavelenght (130–160 nm). The device has been used to image photons generated from charged particles by Cherenkov effect in solid an gaseous radiators, and providing a ring pattern with a radius related to the particle's velocity; experimental values are given for the angle and velocity resolution obtained. Possible applications of the method for particle identification are discussed.