We describe the fabrication and performance of large area glass micro-well detectors (g-MWD) fabricated using APEX® Glass. These microstructure, two-dimensional proportional counters are 85x85 mm^2 square with an array of 100 um diameter wells, 100 um deep, on 200 um centers with crossed anode and cathode electrodes. Their performance in P-10 at 1 atm shows excellent gas gain and stability. Future work will refine the g-MWD fabrication process, demonstrate tiling these detectors to make larger area detectors, and lifetime testing in a closed gas environment.
The g-MWDs are being developed for the Advanced Energetic Pair Telescope (AdEPT), a discovery mission for medium-energy (5-200 MeV) gamma-ray polarimetry, but applications are envisioned in a wide range of medical, military, and homeland security applications.