Year
2010
Abstract
The problem discussed deals with testing radiation portal monitors with due account for two causes considerably complicating the detection of gamma sources by vehicle and train radiation portal monitors under field operation conditions: (i) gamma radiation shielding by materials transported in a vehicle and by the vehicle itself; and (ii) suppression of the natural gamma background measured by the monitor during the vehicle passage between pillars. Experiments were carried out using the vehicle radiation portal monitors installed at different heights above sea level. It is shown that neglecting the above effects can result in considerable deterioration of declared equipment characteristics and, hence, possible misunderstandings and mistakes. The methodology of testing radiation portal monitors approached to field conditions of their operation has been proposed.