In the paper, the pulse characteristics of the detector structures based on GaAs, compensated by Cr are submitted at impact of alpha particles with energy 5.5 MeV from a source 241Am. Based on analysis of experimental data it is established that under condition of homogeneous distribution of electric field intensity (E) in the detector and value E!3 kV/cm, the pulse characteristic may be described within the framework of the PNTOZ theory. It is shown that the offered technique can be used for evaluation of distribution uniformity of electric field intensity on the detector thickness and in some cases, for determination of electrophysical parameters of the detector material.