Sensitivity calibration method for photoelectric tubes and photomultiplier tubes applied in Z-pinch diagnostics

In Z-pinch diagnostics, the soft X-ray scintillator powermeter is an important instrument which is applied in measuring the yield of soft X-ray radiating from Z-pinch plasma on Yang machine and also on the PTS. The spectral responsivity is a key parameter of the powermeter. We calibrated the spectral responsivity of the scintillator and photomultiplier tube system from 50 eV to 1800 eV on Beijing Synchrotron Radiation Facility (BSRF) for obtaining the spectral responsivity of the powermeter. There required another sensitivity comparison between the photomultiplier tube and the photoelectric tube for completing the spectral responsivity calibration for the powermeter. We designed a relative sensitivity calibration system for this job. In this paper, we present the configuration and working procedure of the relative sensitivity calibration system. The calibration method and calibration results are reported as well.