UKAEA-CCFE-PR(25)309
A shinethrough detector and interlock for Neutral Beam Injection operations on MAST-U
Neutral Beam Injection (NBI) is a powerful and very commonly used tool on machines used in the development of magnetically confined fusion power. Not all the neutral beam power is deposited within the plasma. This shinethrough power must be dealt with in the plasma vessel and any components irradiated by it must be protected against excessive heating. This paper describes the design, implementation and testing of a shinethrough detector and interlock for the MAST-U machine. It is based on the detection of the infra-red emission from the beam dump which can then be used to terminate the beam pulse if this exceeds a required threshold. The effects on the detected signal of loosely bound material (“dust”) on the beam dump is also discussed.