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

TL;DR

This paper describes the design, development, and implementation of a neutron-dominated irradiation station at CERN's n_TOF facility, enabling radiation damage studies under realistic accelerator conditions with remote handling to ensure safety.

Contribution

It introduces a new irradiation station at CERN that allows neutron-damage testing in conditions similar to accelerator operation, with remote handling and safety measures.

Findings

Station has 24 positions for samples up to 100 cm3.

Samples can be exposed to MGy neutron doses annually.

Remote handling procedures ensure personnel safety.

Abstract

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 in the Neutron Time-Of-Flight (n\_TOF) facility, taking advantage of the secondary radiation produced by the neutron spallation target. 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 doses in the MGy range per year, with minimal impact on the n TOF facility operation. The station has twenty-four 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.