Two-dimensional imaging triple-GEM detector with resistive anode readout

The resistive anode readout facilitates a good spatial resolution with a large reduction of the electronics channels. The application of such readout method on a 100 x 100 mm(2) triple-GEM detector is presented. The detector anode covers 88 x 88 mm(2) sensitive area and consists of 11 x 11 resistive cells with the cell dimension of 8 x 8 mm(2). The detector has been tested by using a Fe-55 source (5.9 keV) and an X-ray tube (8 keV). It is found that the spatial resolution (sigma) is about 120 mu m with the intrinsic detector response better than 100 mu m. The position nonlinearity of the whole sensitive area is better than 3%. The energy resolution for 5.9 keV X rays is around 20% (FWHM) and the gain nonuniformity between different cells is better than 7%. The detector shows a quite good 2D imaging performance as well. Especially, the detector costs only half of the number of the electronics channels compared with that using the 2D strip readout.