A soft X-ray cryogenic radiometer built on BSRF

Abstract

In the field of the high injection rate X-ray meterage, currently there are no national standards in China, which are urgently needed in areas such as inertial confinement fusion diagnosis and aerospace observation. Globally, many metrology laboratories have developed their own meterage standards based on Cryogenic radiometers. And one soft X-ray cryogenic radiometer has been installed at 4B7B experiment station on Beijing Synchrotron Radiation Facility to measure the X-ray power from 50 nW to 1 $$\upmu \hbox {W}$$ . The purpose is to verify the accuracy of the X-ray power measurement and the performance of the cryogenic radiometer. The spectral responsivity of a Si photodiode detector calibrated in the Physikalisch-Technische Bundesanstalt of Germany is calibrated at 750 eV again with the cryogenic radiometer based on synchrotron light source. Some important performance parameters (e.g., time constant, responsivity, and nonequivalence error) of the cryogenic radiometer were measured and were in agreement with the design indexes. Calibration results show that total relative uncertainties of X-ray power measurement were below 1% ( $$k=1)$$ , and that good consistency was received compared with the calibrations done by the PTB. The cryogenic radiometer built at 4B7B is reliable and accurate for soft X-ray power measurement. And the performance of the cryogenic radiometer is also very good.