Upgrade of the tangential gamma-ray spectrometer beam-line for JET DT experiments

Abstract

The JET tangential gamma-ray spectrometer is undergoing an extensive upgrade in order to make itcompatible with the forthcoming deuterium-tritium (DT) experiments. The paper presents the resultsof the design for the main components for the upgrade of the spectrometer beam-line: tandem collima-tors, gamma-ray shields, and neutron attenuators. The existing tandem collimators will be upgraded byinstalling two additional collimator modules. Two gamma-ray shields will define the gamma-ray field-of-view at the detector end of the spectrometer line-of-sight. A set of three lithium hydride neutronattenuators will be used to control the level of the fast neutron flux on the gamma-ray detector. Thedesign of the upgraded spectrometer beam-line has been supported by extensive radiation (neutron andphoton) transport calculations using both large volume and point radiation sources.