A model of breakdown in parallel-plate detectors

Parallel-plate avalanche chambers (PPACs) have many desirable properties as fast, large area, particle detectors. However, the maximum gain is limited by a form of violent breakdown that limits the usefulness of this detector, despite its evident other qualities. A previous experimental study is now complemented by a quantitative model of the breakdown phenomenon, based on the "streamer theory". The model reproduces well the peculiar behaviour of the external current, as observed in PPACs and resistive-plate chambers. Other breakdown properties measured in PPACs are also well reproduced. Some limitations of the model are discussed and alternative mechanisms are proposed.<
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