ABSOLUTE SENSITIVITY OF THE VUV SPECTROGRAPH FOR PLASMA DIAGNOSTICS

Measurements of spatial and temporal variation of spectra in the wavelength range from vacuum ultraviolet (VUV) to soft x-ray (SX) are necessary to determine radiation power losses and ion density profiles which directly relate to the impurity transport, confinement and sources in magnetically confined plasmas. We developed space- and time-resolving VUV (150-1050 A) [1] and SX (20-350 A) [2] spectrographs and applied for impurity diagnostics in the tandem mirror GAMMA 10 [3]. For quantitative analyses of emission lines, it is important to characterize the absolute sensitivity of these spectrograph systems throughout their wavelength ranges. Previously, we measured the absolute sensitivities of VUV spectrograph by changing the incident light angle of the VUV spectrograph. We have changed the recording camera for improving the sensitivity of the VUVspectrograph. In this report, we show the absolute sensitivity of the VUV spectrograph with using a new CCD camera.