Performance of a triple-GEM detector with capacitive-sharing 3-coordinate (X-Y-U)-strip anode readout

The concept of capacitive-sharing readout, described in detail in a previous study, offers the possibility for the development of high-performance three-coordinates (X-Y-U)-strip readout for Micro Pattern Gaseous Detectors (MPGDs) using simple standard PCB fabrication techniques. Capacitive-sharing (X-Y-U)-strip readout allows simultaneous measurement of the Cartesian coordinates x and y of the position of the particles together with a third coordinate u along the diagonal axis in a single readout PCB. This provides a powerful tool to address multiple-hit ambiguity and enable pattern recognition capabilities in moderate particle flux environment of collider or fixed target experiments in high energy physics HEP) and nuclear physics (NP). We present in this paper the performance of a 10 cm x 10 cm triple-GEM detector with capacitive-sharing (X-Y-U)-strip anode readout. Spatial resolutions of the order of sigma(res)(x) = 71.6 +/- 0.8 mu m for X-strips, sigma(res)(y) = 56.2 +/- 0.9 mu m for Y-strips and sigma(res)(u) = 75. 2 +/- 0.9 mu m for U-strips have been obtained at a beam test at Thomas Jefferson National Accelerator Facility (Jefferson Lab). Modifications of the readout design of future prototypes to improve the spatial resolution and challenges in scaling to large-area MPGDs are discussed.