High Bias X-ray Photocathode Development for the BHx Streak Camera

The BHx x-ray streak camera is under development at the Laboratory for Laser Energetics (LLE). Streak camera time resolution is limited by the picosecond scale electron time of flight difference. The time-of-flight difference in BHx is minimized by using a high bias DC extraction field of 10 KV/mm. Avoiding breakdown in high bias fields requires additional consideration in photocathode development including the surface roughness of the coating and substrate mechanical properties to avoid deflection under electrostatic forces. We present x-ray photocathode development work including breakdown testing under a 20 KV bias, measurements of KBr coating surface roughness, and photocathode quantum efficiency from incident x-rays in the 1-20 KeV range.



This material is based upon work supported by the Department of Energy [National Nuclear Security Administration] University of Rochester “National Inertial Confinement Fusion Program” under Award Number(s) DE-NA0004144.