1. General Seminars

Two GEM Applications: Forward EIC Tracker with Zigzag-Strip Readout & Muon Tomography for Homeland Security

by Marcus Hohlmann (Inst. Technology)

Aula Seminari (LNF INFN)

Aula Seminari


Via Enrico Fermi, 40 00044 Frascati
Work on two applications of Gas Electron Multiplier technology is presented. The first application is a tracker for the forward region of an experiment at a future Electron Ion Collider (EIC) in the U.S. Specifically, the development of a cost-effective readout structure with zigzag strips for large-area GEM detectors is discussed. The zigzag structure allows a significant reduction in the number of strips and electronic readout channels for 1D detectors while preserving good spatial resolution. Recent results on efficiency, cross-talk, and angular resolution obtained from a beam test of a 1-m long trapezoidal prototype detector with radial zigzag strips are presented. Corrections for the non-linear strip response improve the angular resolution from 240μrad to 170μrad, which corresponds to just 12% of the angular pitch of the zigzag strips. The second application is GEM-based muon tomography that aims at 3D-imaging of well-shielded high-Z material, e.g. nuclear contraband in cargo for homeland security. This technique exploits multiple scattering of atmospheric cosmic ray muons, which is stronger in dense, high-Z nuclear materials than in low-Z and medium-Z shielding materials. The imaging performance of a compact Muon Tomography Station that tracks muons using 30cm×30cm Triple-GEM detectors with 2D readout placed on four sides of a 27-liter cubic imaging volume is presented. Using the observed scattering signatures, shielded objects can be distinguished from each other according to their radiation lengths. A 75cc depleted uranium cube is successfully imaged through 2-3cm thick medium-Z bronze shielding material.