Magnetothermal instability may affect high critical current density Nb 3Sn superconducting strands that can quench even though the transport current is low compared to the critical current with important implications in the design of next generation superconducting magnets. 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 magnetothermal instability in superconducting Nb 3Sn-strands. The setup is based on Q-switched laser technology which is able to provide a localized perturbation in nanosecond time scale. Using this technique the energy deposition into the strand is well defined and reliable. The laser is located outside the cryostat at room temperature. The beam is guided from room temperature on to the superconducting strand by using a UV-enhanced fused silica fiber. The strand is mounted on a VAMAS barrel. A part of the beam's energy is absorbed into the strand acting as the trigger energy for the magnetothermal instability. In this paper the experimental setup and the calibration of the absorbed energy is presented.
An experimental setup to measure the minimum trigger energy for magnetothermal instability in Nb3Sn Strands / E. Takala, B. Bordini, J. Bremer, C. Balle, L. Bottura, L. Rossi. - In: IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY. - ISSN 1051-8223. - 22:3(2012), pp. 6000704.1-6000704.4. ((Intervento presentato al 22. convegno International Conference on Magnet Technology (MT) tenutosi a Marseille nel 2011.
An experimental setup to measure the minimum trigger energy for magnetothermal instability in Nb3Sn Strands
L. Rossi
2012
Abstract
Magnetothermal instability may affect high critical current density Nb 3Sn superconducting strands that can quench even though the transport current is low compared to the critical current with important implications in the design of next generation superconducting magnets. 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 magnetothermal instability in superconducting Nb 3Sn-strands. The setup is based on Q-switched laser technology which is able to provide a localized perturbation in nanosecond time scale. Using this technique the energy deposition into the strand is well defined and reliable. The laser is located outside the cryostat at room temperature. The beam is guided from room temperature on to the superconducting strand by using a UV-enhanced fused silica fiber. The strand is mounted on a VAMAS barrel. A part of the beam's energy is absorbed into the strand acting as the trigger energy for the magnetothermal instability. In this paper the experimental setup and the calibration of the absorbed energy is presented.File | Dimensione | Formato | |
---|---|---|---|
06069563.pdf
accesso riservato
Tipologia:
Publisher's version/PDF
Dimensione
420.67 kB
Formato
Adobe PDF
|
420.67 kB | Adobe PDF | Visualizza/Apri Richiedi una copia |
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.