Charge plasma erosion for short-range partially and totally stripped ions stopped in silicon radiation detectors

Abstract

Calculations are made on the erosion by an applied electric field of the charge carrier plasma formed by an ion stopped in a silicon radiation detector. The recent work on this by Seibt, Sundström and Tove is extended to make allowance for the strong variation of linear carrier density with distance along the plasma as produced by partially and totally stripped ions. The published plasma times for 22 MeV 16O ions and 252Cf light fission fragments, both of about 15 μm range, can then be accounted for if transfer from slow cylindrical to fast spherical erosion geometry occurs when a plasma length of about 6 μm remains uneroded. Evidence that this length may be the same for all ions of different ranges is discussed. It is suggested that erosion into the length of a non-uniform plasma column occurs primarily from the end at which the linear carrier density deposited is smaller, although this awaits experimental confirmation.