Modeling and Analysis of Background Oscillations on Hybrid-CMOS Ultrafast X-Ray Imagers*

Hybrid-CMOS (hCMOS) nanosecond X-Ray Imagers are a powerful time-resolved HED diagnostic due to their sensitivity to visible light, x-rays, and charged particles. However, significant pseudo-sinusoidal background oscillations have been observed in these sensors when exposed to an early incident excitation, a phenomenon that has been experimentally linked the sensor’s bond wire inductance. We analyze the oscillations both in the time domain and spatially to account for variations on the pixel level. Both theoretical techniques and analysis of experimental data have shown that the oscillations are a global sensor phenomenon. In addition, we effectively describe the oscillations with a physics-based model, giving further insight into the processes affecting them. This technique allows the hCMOS user to subtract out the oscillations from their measurements and improve accuracy.