The anisotropy coefficient in Cerenkov counting

We present an improved Cerenkov standardization method, which takes into account the directional nature of the Cerenkov light. A new expression for the Cerenkov counting efficiency is derived by assuming that the generation of photoelectrons at the photocathode is described by the Poisson law. In this procedure, the average energy that Cerenkov light needs to create one photoelectron at the photocathode and the anisotropy coefficient are confirmed as essential parameters for the characterization of the detection system. We study the influence of different measurement conditions (i.e., vial type, volume, acid and salt concentrations or spectrometer model) on these two parameters.