Dual MCP gated image intensifier for online high-energy x-ray detection

Compton photography is a crucial diagnostic technique that utilizes picosecond ultra-short pulse lasers to generate hard x rays (50-200 keV) for backlighting inertial confinement fusion capsules at stagnation time, providing fuel density distribution measurements. To enhance the signal-to-noise ratio of backlighting under limited picosecond laser energy conditions, an online hard x-ray detector with high detection efficiency and gating capability is required to mitigate interference from long-duration x-ray pulses. To address this, we developed a dual microchannel plate (MCP) gated image intensifier system. MCP devices with varying specifications, containing 37% and 51% lead by weight, were fabricated and integrated into image intensifiers for detective quantum efficiency testing. The results showed that the dual MCP image intensifier with 37% lead achieved a maximum detective quantum efficiency of ∼4.48%, comparable to that of the AXIS system at the National Ignition Facility as reported in literature. Furthermore, the dual MCP image intensifier with 51% lead demonstrated a significantly higher quantum detection efficiency of 7.15%. Experiments conducted at the ShenGuang-II upgraded facility tested the spatial resolution and gating functionality of the dual MCP gated image intensifier, revealing a spatial resolution of 2.09 lp/mm and effective suppression of nanosecond-long x-ray interference.