Neutron Detector Calibration for the KATANA Facility: Experimental and Computational Validation of Water Activation Neutron Emission

KATANA is a water activation facility located in the TRIGA Mark II reactor of the Jožef Stefan Institute in Ljubljana, Slovenia. Since its commissioning it has contributed to a better understanding of water activation processes and their modelling, which is important in the context of the future operation of the ITER tokamak. The facility is designed to provide a flexible, benchmark-quality environment for the validation of computational tools for the activation of water. It will also support shielding experiments, in particular for ITER-relevant materials, and serve as a stable source of high-energy gamma rays and neutrons. This paper presents the calibration of 3He and BF3 neutron detectors used to measure neutron emission from the decay of 17N. The calibration was performed at the Czech Metrology Institute using a well-characterized graphite-moderated thermal neutron reference field. The calibrated acquisition system is then used in conjunction with Monte Carlo particle transport simulations to obtain the total neutron emission within the measurement volume of the KATANA water activation facility. The results form a basis for the determination of the integral cross section of the 17O(n,p)17N reaction, a nuclear reaction that is still insufficiently described in the literature.