An Experimental Setup to Measure the Minimum Trigger Energy for Magneto-Thermal Instability in Nb3Sn Strands

by Eelis Tapani Takala (University of Turku)

Tuesday 6 Mar 2012, 11:00 → 12:00 Europe/Zurich

30/7-010 (CERN)

Magneto-thermal instability may affect high critical current density Nb3Sn superconducting strands that can quench even though the transport current is low compared to the critical current. The instability is initiated by a small perturbation energy which is considerably lower than the Minimum Quench Energy (MQE). At CERN, a new experimental setup was developed to measure the smallest perturbation energy (Minimum Trigger Energy, MTE) which is able to trigger the magneto-thermal instability in superconducting Nb3Sn-strands. The setup is based on Q-switched laser technology which is able to provide a localized perturbation in nano-second time scale. Using this technique the energy deposition into the strand is well defined and reliable. In this presentation the instability is briefly discussed and the technical implementation, the critical aspects of the design and some preliminary results are shown. The objective is to go through the broad subject in intuitive manner without entering into details.

Slides ETakalaMagnetSeminar.pdf