OSCILLATING SUPERLEAK TRANSDUCERS FOR QUENCH DETECTION IN SUPERCONDUCTING ILC CAVITIES COOLED WITH HE-II *

Abstract

Quench detection for 9-cell ILC cavities is presently a cumbersome procedure requiring two or more cold tests. One cold test identifies the cell-pair involved via quench field measurements in several pass-band modes. A second test follows with numerous fixed thermometers attached to the culprit cell-pair to identify the particular cell. A third measurement with many localized fixed thermometers is necessary to zoom in on the quench spot. We report here on a far more efficient alternative method which utilizes a few (e.g. 8) oscillating superleak transducers to detect the He-II second sound wave driven by the defect induced quench. Using a 9-cell reentrant cavity we identified the quench location in one cold test by powering several modes of the fundamental pass-band. Results characterizing the defect location with He-II second sound detection and corroborating measurements with carbon thermometers will be presented.