Intrinsic response time and related quantities describing semiconductor avalanches

Two definitions of the intrinsic response time of a semi-conductor avalanche are in use which have not yet been very well distingusihed. It is shown that these response times and related quantities, such as the `average¿ or `effective¿ ionisation rate ¿¿, and its field derivative ¿¿, occur in well defined families. Among other things, it is shown that an accepted expression for ¿¿ is not consistent with either of these two response times.