Measurement of thick target neutron yields generated by accelerated heavy ions
Résumé
In accelerator facilities, due to their high penetration through matter, neutrons emitted
from the interaction of high intensity primary beams with thick targets represent a risk of
radiation hazards that needs to be well characterized. The objective of the ongoing TTNY
(Thick Target Neutron Yields) experimental program at GANIL is to measure neutron yields
generated by the interaction of heavy ions (12C to 208Pb, from 4 MeV/u to 95 MeV/u)
with thick targets (natCu, natNb, natC). Double differential (angular and energy) secondary
neutron spectra are obtained using two techniques: the activation of thin foils and neutron
ToF measurements. Measurement results are compared to Monte-Carlo transport codes
(PHITS and FLUKA) in order to benchmark the physics models implemented in the codes
to take into account the wide range of nuclear reactions involved. The data collected during
the experimental program will also allow improving these physics models. In addition, data
obtained with the niobium target (12C (95MeV/u), natNb) are of high interest for the safety
studies associated with the upgrade of the SPIRAL1 facility at GANIL since this beam and
target combination is the one considered to evaluate the upper limit of neutron radiation
hazards associated with the operation of the facility.