Hard-x-ray diamond sensors for in-flight runaway electron detection on SPARC

This paper presents the design of a pair of in-vessel x-ray cameras for SPARC. These cameras have mirrored tangential toroidal views and aim to measure the anisotropic thin-target bremsstrahlung emitted by runaway electrons interacting with the background plasma in the 10–30 keV range. This diagnostic is planned as one of the safeguards against off-normal current ramp-up scenarios, in particular during early SPARC operation. The motivations behind this diagnostic are presented, and the design is detailed with an emphasis on constraints specific to SPARC.