A combination drift chamber/pad chamber for very high readout rates

Details of the construction of high-rate, mid-sized (1-m*2-m) pad chambers, intended for use in Fermi National Accelerator Laboratory (FNAL) experiment E-771, are described. Each gas volume module represents a chamber doublet: two identical anode wire planes, two transverse strip planes, and two pad planes. Wire signals, from 8-mm square cells, are recorded via TDCs; corresponding stripe and pad image signals are latched. Pad sizes range from 0.8 cm*3.6 cm to 3.2 cm*35 cm. In addition to facilitating pattern recognition, pad signals are also used as inputs to an online, high transverse momentum trigger processor.<
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