Range of gamma quanta in the beryllium target

Changes of an initial brake range of gamma quanta in a sample are analysed. It is shown that the main mechanism influencing g quanta range form in a sample of beryllium is Compton’s effect. In work this amendment is considered in the analysis of an exit of photoneutrons. However unlike the models considered in other works at the accounting of Compton dispersion parametrization isn’t used.