Design and optimization of resistive anode for a two-dimensional imaging GEM detector

A resistive anode for two-dimensional imaging detectors, which consists of a series of high resistivity pads surrounded by low resistivity strips, can provide good spatial resolution while reducing the number of electronics channels required. The optimization of this kind of anode has been studied by both numerical simulations and experimental tests. It is found that to obtain good detector performance, the resistance ratio of the pads to the strips should be larger than 5, the nonuniformity of the pad surface resistivity should be less than 20%, a smaller pad width leads to a smaller spatial resolution, and when the pad width is 6 mm, the spatial resolution (a) can reach about 105 pm. Based on the study results, a 2-D GEM detector prototype with optimized resistive anode is constructed and a good imaging performance is achieved.