Fuel ion ratio determination using the 14 MeV Tandem neutron spectrometer for JET DTE1 campaign discharges

• Published in: Fusion engineering and design Vol. 184; p. 113259
• Main Authors: Marcinkevicius, B., Eriksson, J., Hjalmarsson, A., Conroy, S., Ericsson, G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2022; Elsevier Science Ltd
• Subjects: Data acquisition; Deuterium; Discharge; Fuel ion ratio; Fuels; Hot plasma; JET; Joint European Torus; Neutron spectrometer; Response functions; Spacecraft; Spectrometers; Tokamak; Toruses; Tritium; Tokamak; JET; Neutron spectrometer; Fuel ion ratio; Hot plasma
• ISSN: 0920-3796; 1873-7196; 1873-7196
• DOI: 10.1016/j.fusengdes.2022.113259

This paper investigates the determination of the fuel ion ratio nT/ntot in fusion experiments using two different approaches. The methods are applied to plasma discharges from the deuterium–tritium campaign at the Joint European Torus (JET) in 1997. Multiple discharges have been analysed using data acquired with the Tandem (KM2) neutron spectrometer, using a new neutron spectrometer response function and improved line-of-sight information. The two different approaches were generally similar with the exception of the beam slowing down modelling, handled by two different particle transport codes, namely, TRANSP and PENCIL. The results show that nT/ntot can be determined using Tandem neutron spectrometer data; nT/ntot using both of the approaches are consistent and within the uncertainty for a range of studied discharges. The obtained results support previous studies on nT/ntot determination using neutron spectroscopy. In addition, we have shown that PENCIL can be used instead of TRANSP for a range of discharges which could simplify and speed up the estimation of nT/ntot. The possible limitations of the approach using PENCIL could be investigated using different neutron spectrometer data from the 2021 JET deuterium–tritium campaign. A similar spectrometer like Tandem is planned to be operational at ITER and the results of this paper form the first experimental verification of the capability for nT/ntot measurements with such spectrometers. Further research on this could lead to better understanding of these instruments and their limitations before the start of experiments at ITER. •Fusion reactivities were evaluated using two different approaches using codes PENCIL and TRANSP.•Estimated nT/ntot match within the uncertainty for both of the investigated methods.•The study findings support previous investigations made with similar methods using different neutron spectrometers.•We have shown that in tritium dominated plasmas the computational complexity can be reduced by using PENCIL approach instead of TRANSP.•Current results suggest that similar type spectrometers could be successfully implemented in ITER for plasma diagnostic purposes.