Optical and x-ray streak camera gain measurements

Measurements of streak camera gain as the number of CCD (charge-coupled-device) electrons recorded per single-electron events hitting the streak tube phosphor are presented. The CCD is fiber optically coupled to the streak tube output; there is no image intensifier in the system. The gain is measured from the signal-to-noise ratio (SNR) of the recorded photoelectrons. This technique allows us to verify that the photoelectron SNR follows Poisson statistics and to establish the linear dynamic range. Superpixel histograms of sparse streak records are also used to generate the pulse-height distribution (PHD) for recording single-electron events and corroborate the gain measurement. The noise factor and the number distribution of secondary electrons emitted per absorbed x ray from Au, KBr, and CsI photocathodes are derived from the PHD’s recorded with an x-ray streak camera.