A GEM readout with radial zigzag strips and linear charge-sharing response

• DOI: 10.1016/j.nima.2017.12.074
• Publication Date: 2018-01-10T08:11:25Z
• Authors: Aiwu Zhang; Marcus Hohlmann; Babak Azmoun; Martin L. Purschke; Craig Woody
• Keywords: High Energy Physics - Experiment (hep-ex); Physics - Instrumentation and Detectors; 0103 physical sciences; FOS: Physical sciences; Instrumentation and Detectors (physics.ins-det); 01 natural sciences; High Energy Physics - Experiment

We study the position sensitivity of radial zigzag strips intended to read out large GEM detectors for tracking at future experiments. Zigzag strips can cover a readout area with fewer strips than regular straight strips while maintaining good spatial resolution. Consequently, they can reduce the number of required electronic channels and related cost for large-area GEM detector systems. A non-linear relation between incident particle position and hit position measured from charge sharing among zigzag strips was observed in a previous study. We significantly reduce this non-linearity by improving the interleaving of adjacent physical zigzag strips. Zigzag readout structures are implemented on PCBs and on a flexible foil and are tested using a 10 cm by 10 cm triple-GEM detector scanned with a strongly collimated X-ray gun on a 2D motorized stage. Angular resolutions of60-84 urad are achieved with a 1.37 mrad angular strip pitch at a radius of 784 mm. On a linear scale this corresponds to resolutions below 100 um.<br/>16 pages, 18 figures, submitted to NIM A<br/>