Abstract: Fast ion losses in tokamak plasma can reduce the heating efficiency. Fast ion loss detector (FILD) can simultaneously measure the loss rate, energy, and pitch angle of fast ions, making it one of the important means for monitoring and studying the phenomenon of fast ion losses. Based on the discharge parameters of the Chinese HL-3 device, the installation position of the probe is confirmed by simulating the motion trajectory of 80 keV deuterium ions in the HL-3 device with different initial pitch angles at first. Secondly, the collimator size is confirmed by simulating the motion trajectory of deuterium ions under different incident energy, magnetic field strength, and incident angles. Thirdly, by simulating the transverse and longitudinal maximum movement distance of deuterium ions on the silver-doped zinc sulfide ZnS(Ag) scintillator screen after passing through the collimator with designed size, the size of the scintillator screen is confirmed. Finally, the designed fast ion loss detector (FILD) based on the silver-doped zinc sulfide ZnS(Ag) scintillator screen is installed in the HL-3 device for experimental research. The research results show that the fast ion loss detector (FILD) can successfully measure the fast ion loss signal and monitor the fast ion loss induced by the toroidal Alfvén eigenmodes (TAE) mode.

Key words: fast ion loss, energy, pitch angle, ZnS(Ag), toroidal Alfvén eigenmodes