The GEM Technology for the SBS at Jefferson LabF. Noto, V. Bellini, E. Cisbani, and C. Sutera
INFN Sez. di catania, Università di Catania, Italy
INFN Sez. Roma, Italy
The Gas Electron Multiplier (GEM) technology has proven to tolerate rate up to 50 MHz/cm2 without noticeable aging and to provide the required resolution on working chambers up to 33x33 cm2. The SBS GEM chambers have been designed in a modular way: each chamber consists of 3 adjacent GEM modules. Each GEM module has an active area of 40x50 cm2, which 2 represent the current standard double mask GEM technology limit. The design of the module using COMSOL has optimized the active area, surrounded by a tiny 8 mm width mechanical frame of Permaglas™ which embeds the protection resistors that distribute the high voltage to the GEM foils and includes the gas inlet-outlet pipes. In order to safely guarantee the required tracking performance, an additional 2D small plane of high resolution silicon detector is planned to be placed before the SBS dipole.