A model of hybrid-CMOS background oscillations on NIF x-ray diagnostics

Hybrid-CMOS (hCMOS) x-ray imagers are an essential component of many HED diagnostics; their nanosecond integration times and wide sensitivity to visible light, x-rays and charged particles make them a powerful, versatile sensor. However, pseudo-sinusoidal oscillations in their signal background have been previously observed, which significantly affect measurements in the presence of an early incident excitation. We discuss new characterizations of these background oscillations reinforcing prior observations of their connection to the physical sensor circuitry. In addition, we show how a refined mathematical model can be used to make predictions for the effects of these oscillations on measurements from x-ray diagnostics at the National Ignition Facility that incorporate hCMOS imagers, such as SLOS, the Single Line Of Sight camera.