Development of stainless steel gas electron multipliers

We will develop gas electron multipliers GEMs) that are robust in negative ion gas to improve the sensitivity of X-ray Polarimeters.

We will develop a technique for fabricating GEMs that will both maintain the required spacing over arbitrarily large areas and be self-aligning. It will be based on separating two tensioned foils.

We will establish the foil tensioning technique and the optimum spacing between the foils. 

• When the process is finalized, we will formalize the foil tensioning technique and measure creep, temperature stability and flatness using methods established for GEM testing.
• Finally we will assemble a 3x7 cm² GEM that will be integrated into a polarimeter and we will measure the gain uniformity over the area of the GEM.