The electronics of E-577 (elastic-scattering) FERMI-National Accelerator Lab
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What Goes On Roughly (in E577): Something comes down the beam pipe hitting the beam scintillators and something trips off the backward arm ("s" for slow) scintillators. This coincidence is called a B.S. When this happens Roy's LeCroy generates a B.S. strobe (within nanoseconds). Since the s scintillators are closer to the Portakamp than the B scintillators, the s signal is delayed in a length of cable to arrive coincident with the B signal (see later section on "Fast Logic"). This strobe is sent to the backward arm C.R.'s and causes the wire chamber information to be latched up. (In order to make sure that you catch the wire signal at the C. R. input when the B. S. strobe comes, delay the signal from the wire. . amps by running the wire amp signals through a carefully calculated length of delay stripline at the plug in end of the C. R. The width of a pulse that a wire amplifier puts out is about 50 ns. The width of Roys fast logic pulse is about 10 ns, so the B. S. strobe has a little leeway in catching the wire amp. signal. Meanwhile, something goes through the forward arm. It takes about 700 ns. to make this trip one way. The LeCroy decision for a good event, "MASTER RIGGER", comes about 1.5-2 ns after the B.S. strobe. The backward C.R. must hold the wire information for that amount of time.