A high-resolution neutron spectroscopic camera for the SPARC tokamak based on the Jet European Torus deuterium–tritium experience

Abstract

Dedicated nuclear diagnostics have been designed, developed, and built within EUROFUSION enhancement programs in the last ten years for installation at the Joint European Torus and capable of operation in high power Deuterium–Tritium (DT) plasmas. The recent DT Experiment campaign, called DTE2, has been successfully carried out in the second half of 2021 and provides a unique opportunity to evaluate the performance of the new nuclear diagnostics and for an understanding of their behavior in the record high 14 MeV neutron yields (up to 4.7 × 1018 n/s) and total number of neutrons (up to 2 × 1019 n) achieved on a tokamak. In this work, we will focus on the 14 MeV high resolution neutron spectrometers based on artificial diamonds which, for the first time, have extensively been used to measure 14 MeV DT neutron spectra with unprecedented energy resolution (Full Width at Half Maximum of ≈1% at 14 MeV). The work will describe their long-term stability and operation over the DTE2 campaign as well as their performance as neutron spectrometers in terms of achieved energy resolution and high rate capability. This important experience will be used to outline the concept of a spectroscopic neutron camera for the SPARC tokamak. The proposed neutron camera will be the first one to feature the dual capability to measure (i) the 2.5 and 14 MeV neutron emissivity profile via the conventional neutron detectors based on liquid or plastics scintillators and (ii) the 14 MeV neutron spectral emission via the use of high-resolution diamond-based spectrometers. The new opportunities opened by the spectroscopic neutron camera to measure plasma parameters will be discussed.

Diamond based neutron detector in high temperature environments of 200 °C

“…Neutron energy and flux measurements are essential for assessing the ion temperature in future nuclear fusion power plants [1][2][3]. As research in this field advances significantly, neutron detectors capable of withstanding harsh environments are needed.…”

A Highly Versatile X-ray and Electron Beam Diamond Dosimeter for Radiation Therapy and Protection

“…High-quality “electronic-grade” diamond samples with an impurity concentration three orders of magnitude lower than natural diamond are now available at a relatively low cost, thanks to the optimization of the chemical vapor deposition (CVD) technique. Dosimeters based on CVD diamond are, indeed, widely used for EBRT [ 14 , 15 , 16 , 17 , 18 ] and IORT [ 19 , 20 , 21 ], as well as for soft X-rays [ 22 , 23 , 24 ], UV light [ 25 , 26 ], charged particles [ 27 , 28 , 29 ], and neutrons [ 30 , 31 , 32 ].…”