Summary: | The gas electron multiplier technology has been proven to tolerate rat e
larger than 50 MHz/cm2 without noticeable aging and to provide sub resolution
on working chambers up to 45 cm x 45 cm. A new gas electron multiplier-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 gas electron multiplier modules, with an active area
of 40 cm x 50 cm each. We optimized the gas flow inside the gas electron
multiplier 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 gas electron multiplier 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.
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