Thin foil proton recoil spectrometer performance study for application in DT plasma measurements.

Abstract

The Thin foil Proton Recoil (TPR) technique has previously been used for deuterium-tritium fusion neutron diagnostics [N. P. Hawkes et al., Rev. Sci. Instrum. 70, 1134 (1999)] and is one of the candidates put forward for use in ITER as part of the high resolution neutron spectrometer (HRNS) system [E. A. Sundén et al., Nucl. Instrum. Methods Phys. Res., Sect. A 701, 62 (2013)]. For ITER, the neutron spectrometer's main purposes are to determine the fuel ion density ratio as well as the ion temperature in DT plasma. This work focuses on testing the capability of a proton telescope detector intended for use as part of the TPR spectrometer. The proton telescope has been tested using proton energies in the range of 3-8 MeV. The experimental results cover energy calibration, resolution estimation, and testing the spectrometer's capability to perform background separation using ΔE - E energy cuts. In addition, spectrometer performance in terms of signal to background ratios for ITER-like DT plasma conditions is estimated using Monte-Carlo simulations. Results show that the TPR spectrometer geometry dominates in determining the energy resolution and the ΔE - E energy cuts will significantly reduce the background. In addition, the estimated spectrometer count rates in ITER-like conditions fall below 20 kHz per detector segment.