Ponente
Descripción
One of the key characteristics of a neutron source is the energy spectrum of emitted neutrons. This allows, for example, inferences about the activation of various materials used to irradiate samples composed of different nuclear isotopes. In the case of fusion reactors, however, it is possible to determine basic parameters of the reactor fuel, i.e., the plasma, such as the Ti ion temperature or the fuel ion ratio nT/nD. Among the available techniques, a promising approach to neutron spectrometry in neutron environments relevant to intense neutron sources is the thin-film proton recoil (TPR) method. The proposed system is based on the detection of recoil protons generated in a thin hydrogen-rich converter exposed to the incident neutron beam. By measuring the energy and angular distribution of recoil protons, the incident neutron spectrum can be reconstructed and compared with the Monte Carlo prediction. Currently, the high-resolution neutron spectrometer based on the TPR method is under development at IFJ PAN in Kraków [1 - 3].
This contribution presents a proposal for testing and validating a neutron measurement system during the commissioning and early operation phases of DONES. The proposed tests focus on several key aspects, such as selection of the most optimal detectors, optimization of the geometry stand, verification of detector response under realistic DONES neutron flux conditions, assessment of neutron energy reconstruction capabilities, and benchmarking of simulation models against experimental data. Particular attention will be given to the expected 14 MeV neutron component and to the influence of scattered neutrons originating from surrounding structures.
The campaign is intended to provide an experimental basis for qualifying TPR diagnostics as a neutron spectrometry tool for future fusion neutron facilities. The results will contribute to the development of robust neutron monitoring methodologies and support the establishment of validated diagnostic systems for high-intensity fusion-relevant neutron sources. Similar measurements will be possible and planned for other neutron diagnostic concepts. This will enable the qualification and characterization of the parameters of fusion neutron diagnostic systems designed using numerical modelling.
References
[1] M. Scholz, et al., Neutron spectrometer based on a gas electron multiplier (GEM) detector for fusion reactors, Fusion Eng. Des., 222 (2026) 115480, doi: 10.1016/j.fusengdes.2025.115480,
[2] A. Jardin, et al., GEM detector as a neutron spectrometer for fusion plasmas: some modelling and design aspects, . Instr., 20 (2025) C04015, doi: 10.1088/1748-0221/20/04/C04015,
[3] J. Dankowski, et al.,Development and performance of the thin-foil proton recoil spectrometer for ITER plasma diagnostics, Fusion Eng. Des., 219 (2025) 115263, doi: 10.1016/j.fusengdes.2025.115263,
Acknowledements
This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme. This work was done as part of a project co-financed by ITER Organization, France. Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union, European Commission or ITER Organization. Neither the European Union, European Commission, nor the ITER Organisation can be held responsible for them. This project is co-financed by the Polish Ministry of Education and Science in the framework of the International Co-financed Projects (PMW) program. We gratefully acknowledge Polish high-performance computing infrastructure PLGrid (HPC Center: ACK Cyfronet AGH) for providing computer facilities and support within computational grant no. PLG/2025/018826.