The Gas Electron Multiplier (GEM) technology has been proven to tolerate rate larger than 50MHz/cm² without noticeable aging and to provide sub millimeter resolution on working chambers up to 45 x 45 cm² [Alfonsi et al., 2010]. A new GEM-based tracker is under development for the Hall A upgrade at Jefferson Lab. The chambers of the tracker have been designed in a modular way: each chamber consists of 3 adjacent GEM modules, with an active area of 40 x 50 cm² each [Alcorn et al., 2004]. We optimized the gas flow inside the GEM module volume, using the COMSOL physics simulator framework; the COMSOL-based analysis includes the design of the inlet and outlet pipes and the maximization of the uniformity of the gas flow.

We have defined the procedures for the assembling of the GEM modules and designed a mechanical system (TENDIGEM) that will be used to stretch the GEM foils at the proper tension (few kg/cm); the TENDIGEM is based on the original design developed at LNF [Bencivenni, 2009].

Keywords: GEM foil, TENDIGEM, Fluid dynamic, Simulation, SBS tracker.