Large volume threshold Cerenkov counters

The authors summarize the design of a set of large-volume gas threshold Cerenkov counters to be used in the fixed target experiment E142 at the Stanford Linear Accelerator Center (SLAC). The counters are designed to operate at a pion threshold of 13 GeV/c and will use a 4.0-m effective length of CO/sub 2/ at 0.136-atm pressure as a radiator. A 5-in photomultiplier will be used to detect an expected average of 6.5 photoelectrons per electron scattered through the counter.<
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