Precision interpolating pad chambers

We investigate the ultimate resolution one can expect from a properly designed cathode strip chamber and present results of beam tests of chamber prototypes. Design considerations must include mechanical aspects such as width of the cathode pads, anode-cathode spacing, achievement of gain uniformity, and so on, as well as minimization of electronic noise and choice of an appropriate gas. In beam tests we have demonstrated single-plane resolution of 40 μm (σ) using 2.5 mm strips, and consistent space point resolution from stereo planes. True space points are available because the same avalanche may be viewed from two segmented cathode planes having a relative stereo angle. This capability, coupled with the freedom to choose a cathode pad pattern appropriate for the particular application, makes the technique superior in many situations. The achievable resolution approaches that of silicon or gas microstrip chambers but with only a fraction of the electronics channels for the same sensitive area. The beam test included exposure of the detector to multi-track events so that its ability to resolve nearby multiple hits could be observed.