Design development and implementation of an irradiation station at the neutron time-of-flight facility at CERN

A new parasitic, mixed-field, neutron-dominated irradiation station has been recently commissioned at
the European Laboratory for Particle Physics (CERN). The station is installed within the neutron time-of-
flight (n_TOF) facility, taking advantage of the secondary radiation produced by the neutron spallation
target, with neutrons ranging from 0.025 eV to several hundreds of MeV. The new station allows radiation
damage studies to be performed in irradiation conditions that are closer to the ones encountered during the
operation of particle accelerators; the irradiation tests carried out in the station will be complementary to the
standard tests on materials, usually performed with gamma sources. Samples will be exposed to neutron-
dominated doses in the MGy range per year, with minimal impact on the n_TOF facility operation. The
station has 24 irradiation positions, each hosting up to 100 cm3 of sample material. In view of its proximity
to the n_TOF target, inside protective shielding, the irradiation station and its operating procedures have
been carefully developed taking into account the safety of personnel and to avoid any unwanted impact on
the operation of the n_TOF facility and experiments. Due to the residual radioactivity of the whole area
around the n_TOF target and of the irradiated samples, access to the irradiation station is forbidden to
human operators even when the n_TOF facility is not in operation. Robots are used for the remote
installation and retrieval of the samples, and other optimizations of the handling procedures were developed
in compliance with radiation protection regulations and the aim of minimizing doses to personnel. The
sample containers were designed to be radiation tolerant, compatible with remote handling, and subject to
detailed risk analysis and testing during their development. The whole life cycle of the irradiated materials,
including their post-irradiation examinations and final disposal, was considered and optimized.