The Preliminary Design Review for the High Resolution Neutron Spectrometer (HRNS) diagnostic for ITER was held 24th June 2026 and was successfully completed.

The engineering of HiT and our partner Fagerström, combined with the development efforts of the scientific partners University of Uppsala (Sweden), IFJ-PAN (Poland) and CNR (Italy), resulted in a consistent design confirmed by the positive evaluation of the review committee.

HRNS is a compound system, housing 4 spectrometers of 3 types and observes, through detecting individual neutrons, the spectra of these and derives the fuel ion ratio. This ratio of tritium and deuterium in the plasma is important to control the burning plasma of ITER. The spectra give further information on ion temperature, and low-mass energetic particles such as helium – the product of the DT fusion reaction.