Overview of the activities on the ITER fast-ion loss detector

Latest advancements in the design of the ITER Lost Alpha Monitor diagnostic, also known as fast-ion loss detector (FILD), are detailed in this article. Advanced Hamiltonian full-orbit simulations are performed to estimate the velocity-space of fast-ion fluxes on the diagnostic probe head. Using the ASCOT code, these fluxes are characterized for different spatial spectra of externally applied 3D fields and probe head insertion depths. The probe head is inserted into the scrape-off layer (positioned at the level of the first wall) using a reciprocating system featuring an internal moving shaft, double bellows for vacuum integrity, and an electric actuator with a total radial stroke of (Formula presented) (Formula presented) 50 cm. Detailed structural, electromagnetic, and dynamic analyses of this reciprocating system are presented to validate its mechanical robustness against gravitational and induced electromagnetic forces. Thermomechanical modeling of heat loads on the probe head is used to estimate mechanical stresses and scintillator operating temperature.The light pattern emitted by the scintillator is computed using the FILDSIM code, which incorporates scintillator efficiency and orbit simulations. A 14 m long optical relay, featuring free-form mirrors and radiation-hardened lenses, collects and transmits the scintillator light into a shielding cabinet in the port cell. This cabinet houses the instrumentation for data acquisition (DAQ), digitizers for Faraday Cups, photomultiplier tubes, and charge couple device cameras. Monte Carlo simulations estimate radiation-induced noise on the scintillator and the effectiveness of DAQ shielding in the interspace. Together, these advancements ensure an acceptable signal-to-noise ratio of the Lost Alpha Monitor throughout the entire ITER operation.