Resolution measurement of an interpolating pad chamber in the 9 GeV/ cπ− beam at BNL

Abstract

Results are presented from the first test of a full size barrel prototype Interpolating Pad Chamber for the GEM central tracker in the 9 GeV/ c π − beam at the Brookhaven AGS. An average resolution of 45 μm has been achieved using electronics functionally identical to the final GEM design. Two 50 mRad stereo pad layers combine to give 680 μm resolution in the direction along the chamber. A calibration procedure which uses the data to measure the gains and pedestals for each pad has been developed and is presented together with resolution results from the silicon telescope used to project the tracks into the pad chambers.