MCP image intensifier in the 100-KeV to 1-MeV x-ray range

摘要

Abstract: A high gain x-ray image intensifier with high sensitivity in the 1 MeV x-ray range is presented and a good spatial resolution developed in order to improve the radiographic detection in the experiments. In particular the gold photocathode and MCP thickness have been optimized to give the best trade-off between the dose sensitivity and the spatial resolution. The large useful 60 mm diameter photocathode set on the MCP input converts the x-ray emission into electrons which are multiplied in the MCP and proximity-focused onto the P11 phosphor screen deposited on a fiber optic plate. For x-ray quanta of 1 MeV energy the x-ray image converter is more sensitive than the most sensitive x-ray screen-film systems. Using, for instance, a pulsed x-ray source the authors were able to record pictures of a sphere or of a testing metallic chart for a dose lower than 100 $mu@rad; under these conditions the spatial resolution was greater than 1 lp/mm and the dynamic range was still around 10. Using an x-ray screen film under the same input level the authors have obtained a very low dynamic range and density values actually equal to the noise level. These unique performances fulfill the requirements of a large number of detonic experiments needing a high sensitivity in the 1 Mev x-ray range.!