The tri-band high-resolution spectrometer for the ITER CXRS diagnostic system

The tri-band high spectral resolution spectrometer with gratings in tandem for the charge-exchange recombination spectroscopy diagnostic system on HL-2A tokamak

“…On one hand, the attenuation of NBI makes the signal-to-noise ratio slightly lower; on the other hand, larger Doppler shift of the active component of He II weakens the influence of the left wing on the fit. The temperature agreement of different ion species can be considered as a measurement benchmark because the time of temperature equilibrium establishment among different ions is dozens of times faster than the ion energy confinement time [11]. To access the error-bar of the T i and V t , the CXRS spectra were constructed based on the T i and V t , and the 'noise' was added to the constructed spectra; then the relation between the standard deviation of the T i and V t and the input 'noise' could be easily obtained.…”

“…The He II, C VI and D α spectra are obtained simultaneously by a spectrometer (HES-370) with an echelle grating [10]. After that, an updated CXRS diagnostic was fabricated in which two spectrometers are combined with a transmission grating for the simultaneous measurement of C VI (529.1 nm) and O VIII, and the third spectrometer is employed for the beam D α spectral line by using an independent front-end collection optics [11]. Furthermore, a tri-band high-resolution spectrometer for ITER CXRS diagnostic is exploited, based on three volume transmission gratings and aiming at the simultaneous measurement of the spectral lines with large interval in terms of wavelength.…”