Thesis location: Microirradiation, Neutron Metrology and Dosimetry Laboratory (LMDN) - Cadarache (13)
Start: October 2021
Master's Degree in Physics
Knowledges in physics (atomistic and nuclear), instrumentation and measurements
Taste for computers and data analysis
Enligsh (B2) and good level in French
Age limit: 26 years old unless otherwise stated.
As part of its research activities in neutron metrology, the laboratory uses scintillators for the detection of gamma and neutron radiation. These detectors have a very fast response (less than 1 ns) and a high efficiency. They are widely used for the detection of ionising radiation in research and industry. The response of a scintillator to a gamma or a neutron is different, allowing discrimination between the two components. IRSN has recently acquired two "stilbene" organic scintillators for both time-of-flight measurements at the AMANDE facility and use as neutron and gamma spectrometers. One of these detectors has been specially designed to allow measurements over the neutron energy range (~100 keV - 1 MeV), which is much lower than other current scintillators. Specific studies will need to be carried out to understand how it works and to adapt the methods used today for the energy range from 1 MeV to 20 MeV. The doctoral student will become familiar with the subject via the very extensive documentation that exists on scintillators. He will carry out the complete characterisation of the two stilbene-type scintillators by experimental campaigns on the AMANDE and CEZANE installations of IRSN as well as at the PTB (Germany). The doctoral student will carry out numerical simulations of the experiments with MCNP and GEANT4, in particular to determine the calculated response of the scintillators which will be compared with the measurements. After their characterization, the scintillators will be used to study and validate the energy distribution of the neutron fields of radionuclide sources, with the further development of the time of flight method on these sources. Finally, the doctoral student will participate in the commissioning of the system and will write several scientific publications and reports upstream of his thesis.