Method of protection of the electronic equipment from pulse X-ray radiation
X-ray units with high instantaneous intensity are used in the course of nondestructive testing of massive articles, in radiation tests, and also to impart new properties to various polymer materials. Under these conditions, the input cascades of measuring systems designed to monitor the parameters of processes are subject to a powerful X-ray flux. The flux generates avalanche of secondary electrons in the sensitive part of the primary measuring transducers, which leads to their failure or temporary inoperability due to the thyratron effect in p - n transitions of semiconductor electronic devices. The work has shown the possibility of protecting the input cascades of electronic devices in the ionization zone by shunting the power circuits in real time. Shunting is ensured by the creation in the protective device of high conductivity by the same radiation flux. The possibility of creating protective devices based on semiconductor chambers with walls with high braking power has been considered. The radiation forms in the wall of the chamber a high level of secondary electrons flowing through the plate from a semiconductor with high mobility of conduction electrons. Conduction electrons are formed in a semiconductor in the last stages of electron avalanches caused by high-energy secondary electrons. Such opportunity has been confirmed with calculations for the specific camera with a wall from lead in which the plate from gallium arsenide is placed. The calculations have been carried out for a wall by thickness equal to average length of the free run of a photoelectron. In this case, the electron equilibrium condition is present, that is, the number of secondary electrons produced in the wall as a consequence of the internal photoelectric effect will be equal to the number of electrons absorbed by the wall, but the flux of X-ray photons does not change appreciably. Compliance with this condition gives the greatest shunting effect.