Sensitivity degradation of X-ray diodes in 2 to 6 keV

Spectral responses of aluminum- and gold-cathode X-ray diodes, commonly used in Z-pinch experiments of Qiangguang-I generator, have been calibrated on the 4B7B beamline of Beijing Synchrotron Radiation Facility, with a spectral range of 2.1 to 5.9 keV. Results of different kinds of cathodes, as well as other published data, are compared to check the effect of cathode material, preparation process and usage conditions on the degradation and dispersivity of the sensitivity. Evaporated gold cathodes stored in dry air for several years still have quite uniform spectral responses, while also with a large fall that their responses are only 20% to 25% of those reported data for fresh gold cathodes. Used gold cathodes even show a further fall in sensitivities. The aluminum cathodes exhibit muc