The objective of the proposed work was to investigate the electrical performance of a 250 µm-thick 4H-SiC p-n junction detector after irradiation with DT neutrons (14.1 MeV energy) at high temperature (500 °C). The results showed that the current–voltage (I-V) characteristics of the unirradiated SiC detector were ideal, with an ideality factor close to 1.5. A high electron mobility (µ_n) and built-in voltage (V_bi) were also observed. Additionally, the leakage current remained very low in the temperature range of 298–523 K. High-temperature irradiation caused a deviation from ideal behaviour, leading to an increase in the ideality factor, decreases in the µ_n and V_bi values, and a significant rise in the leakage current. Studying the capacitance–voltage (C-V) characteristics, it was observed that neutron irradiation induced reductions in both Al-doped (p⁺-type) and N-doped (n⁻-type) 4H-SiC carrier concentrations. A comprehensive investigation of the deep defect states and impurities was carried out using deep-level transient spectroscopy (DLTS) in the temperature range of 85–750 K. In particular, high-temperature neutron irradiation influenced the behaviours of both the Z_1/2 and EH_6/7 traps, which were related to carbon interstitials, silicon vacancies, or anti-site pairs.

The design of a compact 2 × 2 diamond matrix with independent and redundant pixels optimized for the spectrometric neutron camera of the SPARC tokamak is presented in this article. Such a matrix overcomes the constraints in dynamic range posed by the size of a single diamond sensor while keeping the ability to perform energy spectral analysis, marking a significant advancement in tokamak neutron diagnostics. A charge pre-amplifier based on radio frequency amplifiers based on InGaP technology transistors, offering up to 2 GHz bandwidth with high robustness against radiation, has been developed. A first single-channel device has been tested and proven to provide a fast signal development time of 20–25 ns, necessary to mitigate pileup effects while offering precise energy measurements. As the diamond sensors may suffer from polarization effects due to the trapping of charges at the diamond/metal interface, a periodical bias inversion can guarantee optimal performance. To facilitate that, a reversible high voltage power supply has been developed. The ongoing development of data acquisition equipment and real-time processing algorithms based on programmable gate arrays further enhances the neutron camera’s capabilities.

Silicon carbide (SiC)-based detectors offer exceptional radiation hardness and thermal stability, making them suitable for neutron spectroscopy in fusion reactor environments, which are characterized by high temperatures and intense neutron fluxes. In this study we demonstrate a 250 µm-thick 4 H-SiC p–n junction detector that maintains stable deuterium–tritium neutron detection performance across the full temperature range from 25 °C to 500 °C, thereby overcoming the limitations commonly encountered with diamond-based detectors. These results highlight the potential of thick SiC detectors for monitoring neutron flux and performing neutron spectroscopy in harsh environments, such as the breeding blanket of fusion reactors.

This study investigates the electrical performance of two 4H-SiC p⁺-i-n⁻ diodes, based on lightly doped epitaxial layers, representative of high-voltage and neutron-detector structures. Each design was implemented in multiple nominally identical devices and characterized over the temperature range 298–623 K, with particular attention to the influence of p⁺ layer fabrication, n-type epitaxial layer thickness, and doping concentration. One diode features an ion-implanted p⁺ layer on a 250 µm thick n-type epitaxial layer, while the other employs an epitaxially grown p⁺ layer on a 100 µm thick n-type epitaxial layer. A comparison of reverse-bias Current–Voltage (I–V) and Capacitance–Voltage (C–V) characteristics indicates that, although both designs exhibit high-quality epitaxial 4H-SiC material, devices with an implanted p⁺ anode tend to show a more pronounced temperature-dependence and degradation of selected electrical parameters in reverse bias than those with an epitaxial p⁺ anode, while forward I–V in the range 298–623 K remains broadly similar for both designs. These observations suggest that anode fabrication and epitaxial design may jointly influence thermal stability, recombination mechanisms, and overall electrical performance, offering guidance for the optimization of 4H-SiC-based power and neutron-detector devices for high-temperature and harsh environments.

The development of high-field, large-bore magnets based on High-Temperature Superconductors (HTS) is a strategic challenge with impact across high-energy physics, fusion energy, and other scientific and societal applications. In particular, the target decay and capture solenoid for the Muon Collider and the central solenoid of next-generation fusion devices both demand solenoids capable of producing a 20 T peak field in a bore larger than 1 m, at 20 K, with stored energy exceeding 300 MJ (single coil). Such performance is well beyond present state-of-the-art, requiring a dedicated programme to validate conductor technologies, magnet architectures, and protection strategies. This paper presents the results of a feasibility study originated from discussions between CERN and Eni on a common solenoid concept serving as technology validation for both high-energy physics experiments and magnetic-confinement fusion devices such as tokamaks. The main result of the study, which brought together universities and research centers, is a “20@20” model coil concept. We report here the rationale for the selection of the target performance of the “20@20” model coil, and the highlights of the study, which was instrumental to identify high priority developments required towards its realization.