Progress of NUV and FUV MCP-based photon-counting imaging detectors

Abstract

Photon counting imaging technology has been widely used in nuclear radiation detection, space environment detection, astronomy observation, nuclear physics and ultra-weak bioluminescence. In this paper, the progress and parameters of NUV (160-320nm) and FUV (102-170nm) photon-counting imaging detectors were described. The NUV detector was developed based on a sealed MCP-image intensifier which comprises input window, photocathode, MCP stack, Ge-layer and its ceramic substrate. To maximize the quantum efficiency, a Cesium Telluride (Cs₂Te) photocathode was adopted, which was deposited on input window and mounted close to the MCP. For the FUV detector, because of the lower cut-off wavelength, there are no suitable window materials in this band and the open-faced design should be used to meet the requirements of the detection. Therefore, a Cesium Iodide (CsI) photocathode deposited on the input surface of the MCP was used to optimize detector efficiency. By using an existing wedge and strip anode (WSA), the imaging performance of the NUV and FUV detectors was tested respectively. Experimental results show that the quantum efficiency of Cs₂Te is 12.1% (at 230nm), the spatial resolution of NUV and FUV detectors is better than 70μm, the dark count rate of NUV and FUV detectors is about 10.5- and 2.3-counts/s*cm² respectively.