Patent ID: 7388201

Claim:
A radiation detector comprising: an electron emitter including a support, a plurality of shafts extending from said support, each one of said plurality of shafts tapering from a base portion toward a tip portion, said tip portion having a diameter between about 1 nm to about 50 nm and said base portion having a diameter between about 20 nm to about 300 nm, each one of said shafts having a length between about 100 nm to about 3,000 nm and an aspect ratio larger than 10, a coating covering at least said tip portions of said plurality of shafts, said coating exhibiting negative electron affinity and being capable of emitting secondary electrons upon being irradiated by radiation; an electron collector positioned to collect electrons emitted from said electron emitter and to produce a signal indicative of the amount of electrons collected; and a signal processor operatively connected to said electron collector for processing said signal to determine a characteristic of said radiation.