UC Berkeley

The combination of a photocathode, microchannel plate stack and photon counting, imaging readout provides a powerful tool for high dynamic range, high spatial resolution, and high timing accuracy detectors for the X-ray to visible light spectral range. Significant improvements in spatial resolution, quantum efficiency, and background rate have made these devices attractive for many applications and are being applied to completely new research areas. We describe the latest developments in high-resolution cross-strip (XS) anode readout for photon counting imaging with microchannel plates (MCPs). We show that the spatial resolution of an MCP detector with the cross-strip readout is now limited only by the MCP pore width. For the first time, we show images of resolution test masks illustrating the exceptional spatial resolution of the cross-strip readout, which at the present time can resolve features on the scale of similar to7 mum with MCP gains as low as 6 x 10(5). Low-gain operation of the detector with high spatial resolution shown in this paper is very beneficial for applications with high local counting rate and long lifetime requirements. The spatial resolution of the XS anode can be increased even further with improved anode uniformity, lower noise front-end electronics, and new centroiding algorithms. This could be important when MCPs with smaller than existing 6 mum pores become commercially available, thus improving the detector resolution down to the few micrometer scale.