High luminosity Gas Electron Multiplier (GEM) tracker for GEp-V experiment at Jefferson lab

The Super Bigbite Spectrometer (SBS) program at Jefferson Lab aims to measure the electromagnetic form factors of the nucleons. Flagship experiment of the program, GEp-V, focuses on measuring electric form factor of the proton (GEp) up to Q² of 12 GeV². SBS program significantly improves the figure of merit by over a factor of 50 compared to previous GEp measurements through the use of an open geometry large acceptance spectrometer for proton detection. However, the open nature of the spectrometer, with a direct line of sight from the target to the tracking detectors, creates an unprecedented high-rate background environment. SBS trackers consist of 16 large area GEM layers designed to handle high background rates. Nevertheless, high voltage supply scheme for GEMs requires optimization to operate under high leakage currents caused by high rates. Previous SBS experiments revealed that conventional voltage divider scheme fails to provide necessary voltages, resulting in decreased GEM efficiencies during experimental running. Consequently, high voltage supply scheme has been optimized and upgraded for GEp-V to ensure high efficiency at anticipated unprecedented luminosities. Presentation will include results comparing upgraded system operating in beam with simulations. These upgrades will be beneficial for future experiments such as the Solenoidal Large Intensity Device (SoLID).