Mixed n–γ fields dosimetry at low doses by means of different solid state dosimeters

A Mock-up of the inboard shield of the ITER International nuclear fusion reactor was realized at the Frascati Neutron Generator (FNG) at ENEA Frascati with the scope to measure the nuclear heating (total dose) in the superconducting coils. High sensitivity MCP-6 and MCP-7 dosimeters were used to measure the low (<150 μGy) expected doses. A dedicated calibration effort was devoted to calibrate the detectors in reference gamma and thermal neutrons secondary standards fields. The TLD’s reading cycle was also optimized for the expected low dose to minimize the signal to noise ratio. The neutron and gamma separation was obtained by the “pair detectors” method. The experimental results (gamma air-kerma and neutron fluence) are compared with the results of Monte Carlo simulations performed with the MCNP-5.2 code and the FENDL-2.1 nuclear data library.

► A Mock-up of the shield of ITER nuclear fusion reactor was realized.
► The scope is to measure the total dose in the superconducting coils.
► High sensitivity TLD dosimeters used to measure the low (< 150 mGy) expected dose.
► Neutron and gamma doses separation attained by the “pair detectors” method.
► The experimental n and g doses agree with Monte Carlo simulations within ±10%.