Spark counting technique with an aluminium oxide film

An aluminium dioxide film deposited on an aluminium plate was attached to a 100 μg uranium target of 2.4 cm diameter electrodeposited on a stainless steel plate. This pair was irradiated with thermal neutron flux (5.7 x 105 n/cm2.sec) produced by Kinki University's reactor UTR-Kinki (1 watt). After neutron irradiation the aluminium dioxide plate was separated from the target plate and attached to an aluminized polyester sheet. High voltage was applied between the aluminized sheet electrode and the aluminium plate electrode. Sparked pulses were counted with the usual scaler. Results indicated that the thickness of the aluminium dioxide depended on time and temperature of electrolysis and sealing time. Spark counting efficiency was calculated to be about 8.5%, lower than that of the usual polycarbonate detectors. (U.K.)