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MSC Seminars
Measurement of Electrical and Mechanical Transients in Nb3Sn magnets
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Europe/Zurich
30/7-010 (CERN)
Description
Abstract:
Mechanical events like slip-stick motion and epoxy cracking are widely believed to cause training of Nb3Sn magnets. These transient events (or short-lived events) can occur throughout the whole ramp of the magnet as have already been shown some decades ago. Over the past two years, the investigation of these transients has been intensified by measuring the signals from the magnet voltage, accelerometers (screwed to the magnet structure), and quench antenna (in the magnet bore) during numerous full ramp-ups of some selected magnets. The most promising measurement is with the quench antenna, which can be used to localise vibrations in the longitudinal direction of the magnet, supported by the accelerometer and voltage data. With hundreds to thousands of mechanical events during each ramp up to the final current, the vibration activity can be mapped from ramp to ramp over the lifetime of the magnet. In addition, the possibilities of mapping flux jumps and flux jump propagation are discussed.
The measurement devices and methods will be shown and discussed in general. Then the results for the last 11T model and FRESCA2 will be used to discuss the method