As part of the development of fourth-generation sodium-cooled fast reactors, the CEA/IRESNE Dosimetry and Instrumentation Laboratory is working on innovative neutron measurement systems capable of operating at temperatures of the order of 600°C, and insensitive to the parasitic phenomena that occur under these conditions. Recently, a new type of optical signal neutron detector (ODN) has been developed at the laboratory. Despite a more complex signal interpretation, this instrument has several advantage: it can be miniaturized and it is intrinsically insensitive to problems of partial discharges and leakage currents that occur in ionization chambers at high temperature.
We propose to pursue the theoretical and experimental development of ODNs to adapt them to high temperatures. The PhD student will further develop the modelling tools already available in the laboratory for simulating the detector response. The work will investigate heavy ion-noble gas interaction cross sections, also a radiative collisional model to predict emission spectra and their temporal dynamics. Part of the work will involve dimensioning a high-temperature prototype and testing it in the JSI TRIGA reactor. Ultimately, the detector will be qualified in the JOYO research reactor as part of a broader experimental program.