Abnormal spectral distortion of a silicon sensor-based single photon counting charge coupled device (PIXIS-XB: 1300R) in detecting laser plasma x-ray source of 20-100 keV

Single photon counting using a charge-coupled device (CCD) is a conventional method of measuring the x-ray production of laser plasma. But the spectrum is seriously distorted when measuring a short pulse laser plasma x-ray source. Here we explore this abnormal spectral distortion using a silicon sensor-based CCD (PIXIS-XB: 1300R). We found that the spectral distortion is caused by the continuous spectrum of Compton scattering electrons and the K- and K-β characteristic lines of Ag elements excited by the harder x-rays of >25 keV. We calibrated the detection efficiency of the incident x-ray, the excitation efficiency of the Ag characteristic lines and the Compton scattering electrons spectrum in the x-ray energy range from 20 keV to 100 keV. We also improve the algorithm of spectrum reconstruction to loosen the exposure level limit markedly. Our effort extends the detecting range of silicon sensor-based CCDs from 0.5-30 keV to 0.5-80 keV. The present analysis can also be used in the spectral extraction of GaAs and CdTe high-Z sensor-based CCDs.