Fabrication and Testing of a Double Ionization Chamber for On-Line Tritium Production Rate Measurements and Comparison with the Standard Liquid-Scintillation Method

Abstract

At the LOTUS facility, an extremely efficient online detector system, based on the detection of the charged particles associated with the ⁶Li(n, α)t reaction, has been designed, fabricated, and tested. The system offers an interesting possibility for directly measuring the tritium production rate (TPR) at any experimental site. The charged particles emitted in opposite directions can be detected by a double parallel plate ionization chamber (DIC) configuration. The real events are identified by employing a coincidence circuit. The complete fabrication details, testing under different conditions, measurement of TPR, and its comparison with the liquid-scintillation method (LSM) are detailed. The DIC response to thermal neutrons agrees well with the theoretical calculations. Also, the detector system is insensitive to a contact gamma dose rate of 1.3 rem/h. The direct TPR measurements and the salient feature of higher efficiency in comparison with the LSM are demonstrated. The TPR determined by both methods are in excellent agreement.