Improvement of the beamline for calibration of the transfer standard in the UV and VUV regions

Abstract

The electron storage ring TERAS was used to calibrate the spectral radiance of transfer standard light sources in the ultraviolet (UV) and vacuum ultraviolet (VUV) regions. This calibration system, constructed at the beamline, is an improvement on a prototype system we constructed previously. The new system is simpler and does not require breaking the vacuum of the calibration system. Also, the signal from the transfer standard light source is strong, the conditions of the light sources (synchrotron radiation and transfer standard light source) can be observed directly (it is possible to evaluate the profiles or some parameters of light sources without breaking the vacuum), the polarimeter is improved and the uncertainty due to the polarization effect is expected to be improved. In addition to describing these improvements, we re-examine some uncertainties.