On the effective recombination cross‐section of charged centres in crystal phosphors

Abstract

AbstractThe effective recombination cross‐section σeff of charged centres measured experimentally is found to be not always equal to the gas kinetical cross‐section σk. σeff is also dependent on the diffusion coefficient D and mobility μ. Such a dependence is enhanced at small free pass length l. In a general case the relation holds σk≦ σeff≦ σμ MD (where σμ is the pure drift cross‐section and MD is multiplication constant due to diffusion; σμ = (4 π R′l)/3, where R′ is the distance at which the potential energy of the free charge in the field of the centre becomes equal to kT). At small σk a temperature dependence can arise with “negative” activation energy σeff ∼ e−E/kT, where E < 0. The limiting case σeff = σk is not trivial because the equality is due to original mutual compensation of drift and diffusion.