Spectral sensitivity calibration of Au and CsI photocathodes of high speed x-ray scanning camera

High speed X-ray scanning camera (XSC) is an extra precision temporal and spatial diagnostic instrument in the inertial confinement fusion (ICF) experiment. In order to quantitatively analyze the measurement results, the spectral sensitivity of XSC, which depends on the response of the transmission photocathode, is necessary to be absolutely calibrated. A method of measuring the spectral response of Au and CsI transmission photocathodes of XSC is described. Based on Beijing Synchrotron Radiation Facility (BSRF), Au and CsI transmission photocathodes with slits are calibrated in the photon energy range of 60 eV-1500 eV and 2.1 keV-5.5 keV. Utilizing the quantum efficiency of the standard detector AXUV-100, the calibrated quantum efficiency of Au and CsI photocathodes are derived. The calibration data agree well with the photoelectric emission theory of Henke.