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The Joint Research Centre (JRC) is the European Commission's science and knowledge service which employs scientists to carry out research in order to provide independent scientific advice and support to EU policy.
The high intensity quasi mono-energetic neutron source at IRMM is driven by a vertical 7 MV Van de Graaff accelerator producing either continuous or pulsed ion beams. The installation has two pulsing systems. One is a fast beam pulsing generating a minimum ion beam pulse width of 2 ns and pulse repetition rates of 2.5, 1.25 or 0.625 MHz, and the other a slow pulsing system giving a minimum pulsing width of 10 μs at an adjustable frequency up to 5 kHz.
The neutron fields that have well defined energies are produced by the nuclear reactions Li(p,n), T(p,n), D(d,n) or T(d,n) giving neutrons within the energy regions 0.3 – 10.0 MeV and 14.5 - 24 MeV.
The IRMM Van de Graaff facility houses six experimental set-ups in two large laboratory halls. The accelerator is operated 24 hours a day and seven days a week and it provides a stable neutron field for more than a week without interruption. Neutron fluxes and neutron energy spectra are monitored and characterised with high precision by long counters, proportional counters, BF 3 counters, Bonner spheres, time-of-flight systems, fission chambers and activation foils. Absolute neutron fluencies are measured using a calibrated recoil proton telescope. Several shadow cones are available for measurements of possible neutron scattering.