Experimental and Monte Carlo study of semiconductor detectors response to 2.45 MeV-3.95 MeV neutrons at NCSR...

Neutron detectors play a vital role in radiation applications, particularly in nuclear, high-energy physics experiments and fusion facilities, where accurate neutron spectrum measurements and flux monitoring are essential. In fusion research, detecting 2.45 MeV neutrons, produced via D-D fusion, is especially important, offering key information on the progress of the reaction. However, accurate neutron measurements at energies below 6 MeV remain challenging due to high background levels, low detector efficiencies, and the fact that many reaction channels are closed. Among the various detection technologies, semiconductor detectors based on diamond and silicon carbide (SiC) are highly favored thanks to their excellent energy resolution and ability to operate in harsh environmental conditions. A common approach in semiconductor neutron detection involves conversion layers (e.g., LiF or hydrogen) to enable detection via secondary charged particles such as tritons, alpha particles, or proton recoils. In this work, we investigate and compare the response functions of a diamond and a SiC detector to fast neutrons at 2.45 MeV, 2.95 MeV, 3.45 MeV, and 3.95 MeV, using direct detection through elastic scattering without the use of conversion layers. For this purpose, a 50 μm single-crystalline diamond and a 50 μm SiC detectors were exposed to quasi-monoenergetic neutron beams at NCSR "Demokritos" in Athens. The resulting experimental spectra were compared with Geant4 simulations to validate the measurements and to extract the detection efficiencies.