Silicon avalanche radiation detectors: the basis for a new in vivo radiation detection probe.

Recent advances in semiconductor technology have made it possible to develop practical silicon avalanche radiation detectors. These detectors are analogous in operation to a gas proportional counter, but are capable of extreme miniaturization. Most importantly these devices have overcome the in vivo limitations of past semiconductor detectors with respect to noise, microphonics, and adaptability to relatively harsh environments. The operation and some useful characteristics of an avalanche detector are outlined. The performance of a probe mounted detector in an in vivo setting is described which illustrates one application of the silicon avalanche detector in this milieu.