Conceptual Design of Ion Temperature Diagnostics for the PI4 device at General Fusion

We report a conceptual design of ion temperature diagnostics for the upcoming PI4 machine at General Fusion. This diagnostics system consists of a high resolution spectrometer (Horiba iHR550) and EMCCD camera (Teledyne Princeton Instruments, ProEM HS: 512BX3). Due to the fast readout speed of the EMCCD camera, this system will be able to measure the Doppler shift and broadening of impurity ions with 1 ms temporal resolution. A numerical inversion based on Bayesian inference will be used to obtain the local ion temperature and velocity from the Doppler spectra measured for more than 10 lines of sight. Its feasibility is being tested based on synthetic data taking the actual viewing geometry into account.