Calibration and test of a 6LiF-diamond detector for the HCPB mock-up experiment at JET

•Diamond detector covered with 6LiF (LiDia) to be used for Tritium production rate at JET.•LiDia calibrated in a reference thermal flux to determine the 6Li mass.•Benchmark experiment performed at the FNG facility using 14 MeV neutrons.•LiDia located in a polyethylene phantom, irradiated and Tritium production measured.•Experimental results compared to MCNP5 simulation, good agreement between experiment and simulation (< ±4%) found.