Design and synthetic diagnostic of a multi-energy hard x-ray camera for profile measurements at WEST tokamak

The WEST tokamak is currently being prepared for long pulse operation with a water-cooled full tungsten divertor. Heating will be provided by radiofrequency systems, including lower hybrid current drive (LHCD). In this context the Princeton Plasma Physics Laboratory has built a compact multi-energy hard x-ray camera (ME-HXR) for space and energy-resolved measurements of the electron temperature, the fast electron tail density produced by LHCD and runaway electrons, and the beam-target emission of tungsten at the edge due to fast electron losses interacting with the target.

This contribution presents the design of the diagnostic, which is based on a novel 2D pixel array x-ray detector with adjustable threshold energy at pixel level. This innovation provides a great flexibility in the energy configuration allowing simultaneous time, space and energy resolved x-ray measurements. The detector has been calibrated in the range 10-100 keV.

A synthetic diagnostic has been developed by incorporating the geometry of the ME-HXR into two different suites of codes for the simulation of LH wave absorption and fast electron Bremsstrahlung production: C3PO/LUKE/R5-X2 and GENRAY/CQL3D. This contribution presents the outcomes of the two codes highlighting their differences.