Front end electronics for the Jet Drift Chamber

The Jet Drift Chamber uses a charge-division readout scheme which requires two amplifiers per sense wire. Since there are 690 sense wires, 1380 amplifiers are needed. It follows that each end cap must accommodate 690 amplifiers, which makes packaging and cooling critical problems. To address these problems, 30 six-layer surface-mount boards, each containing 24 (23 used) amplifiers channels, have been fabricated. Each amplifier can accept up to 2 pC of charge and provide a linear differential output of +or-300 mV, which is used to drive a twisted-pair transmission line up to 70 ft in length. The power dissipation of each board is 1.5 W.<
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