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Accelerator Seminar


"Second Sound as a Cavity Diagnostic Tool"

Don Hartill,
Cornell University




Second sound in liquid helium at temperatures below the lambda point provides a simple and convenient way to identify the quench location in a superconducting rf cavity.  The propagation velocity of second sound is around 20 meters/sec which means that measurement of the arrival time of the second sound wave to 0.1 msec provides 2 mm resolution for the quench location using several second sound sensors.  Second sound is a temperature wave but oscillating superleak transducers respond only to second sound and provide a fast and very sensitive detection technique.  A series of tests using this technique on both single cell and nine cell cavities will be described.  Photos of the flaws identified will also be shown.



Thursday, December 4, 2008

3:30 - 4:30 p.m.

CEBAF Center, Room L102/104

Talk Slides: (Slides)

For more information, please contact Dr. Alex Bogacz or Anne-Marie Valente.