A new neutron beam line for (n, xn) reaction studies

A new neutron beam line facility with low background has been installed on the TANDEM accelerator facility of CEA/DIF at Bruyères-le-Châtel (France) to allow (n, xn) reactions studies with a new neutron-multiplicity detector. Beam neutrons are produced by nuclear reaction between a proton or deuteron beam and a deuterium or tritium target. The neutron beam is defined by a channel going through a shielding system built around the neutron production source. The design of the shielding system has been carried out using the MCNP (version 4C) code. The beam characteristics (size, energy spectra and flux) were measured. The neutron-beam energy range covers 3-25 MeV, the beam being purely monoenergetic below 8 MeV.