THEORETICAL INVESTIGATIONS OF A DOUBLE IONIZATION-CHAMBER FOR ONLINE MONITORING OF TRITIUM PRODUCTION IN FUSION BLANKETS

A double ionization chamber employing a thin coating of enriched (LiF)-Li-6 radiating material offers an effective means of identifying a Li-6(n, alpha)t reaction. The concept is based on the detection of ionization caused by alpha particles and tritons. The charged particles emitted in opposite directions can be detected by a double parallel plate ionization chamber configuration. This method can therefore be employed to directly measure tritium breeding rates inside the fusion blankets. Complete details of the parameters that govern the response of such a detector system are described. A Monte Carlo scheme is developed to determine the direction and energy lost by the particles in traversing various media, and the detector response is calculated from the energy deposited in the ionization region of each chamber. The calculations are performed for the entire energy range of neutrons available in the fusion blankets.