Numerical simulation of dual MCP hard x-ray imaging detector on spatial resolution and detection quantum efficiency

Abstract

Compton radiography is an important diagnostic tool for Inertial Confinement Fusion (ICF), which provides important parameters about integrity, symmetry and ρR areal density of the dense cold fuel surrounding the hot spot. The dual MCPs (Micro-Channel Plate) configuration detector as a key component for Compton radiography has the ability to detect hard x-rays at energies from 40 to 200 keV with higher Detective Quantum Efficiency (DQE). In this work, a set of simulation methods for calculating the DQE and spatial resolution of dual MCPs are proposed. The photoelectric conversion and secondary electron multiplication processes of 59 KeV X-rays in double MCPs were simulated. The first piece of MCP with 51% lead content absorb x-rays volumetrically to improve the DQE and the second piece of MCP provides a large gain to multiply the secondary electrons. The simulation results indicate that the spatial resolution of the dual MCP detector is 186 μm, and the DQE can reach 6.2%, which will ensure the dual MCP-based framing cameras can obtain imploded capsule images with higher signal-to-noise ratio and spatial resolution. The influence of MCP parameters on DQE and spatial resolution was analyzed, and the simulation method will provide an important reference for further optimization of the detector.