New Gas Electron Multipliers at MIT: Fabrication, Processing, and Testing

Gas Electron Multipliers (GEMs) concentrate powerful electric fields through holes in metal foils to turn single drifting electrons into cascades large enough to be easily detected. Gains of 10 - 10$^{3}$ are achieved. Until recently fabricated solely at CERN, new GEMs have been developed by Tech-Etch, a private company located in Plymouth, Massachusetts. We describe the testing of these GEMs for detector use. We also investigate coarser-grained GEMs, which have robustness advantages including ease of manufacture. First results will be given.