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The Electronic Controls Used In A Search For Fractional Charges In Mercury Drops, William Walters, David C. Joyce, Peter C. Abrams, K. R. Koburn, Betty A. Young
The Electronic Controls Used In A Search For Fractional Charges In Mercury Drops, William Walters, David C. Joyce, Peter C. Abrams, K. R. Koburn, Betty A. Young
Physics
At San Francisco State University, we have developed an Automatic Millikan Device (AMI)) for measuring the charge on small drops of Mercury. The device uses a standard atomic physics laboratory Millikan chamber, a piezoelectric driven ink-jet glass dropper, and a laser-photomultiplier system for tracking the motion of the drop. This paper describes the electronic control and error detection system used with the AMO. Signals from this system are sent to a microprocessor which controls the experiment. To this date (Dec 7, 1981), we have measured 175 micrograms of Hg and found no fractional charges in 1.05 x 1020 nucleons.