Small working distances between the objective lenses and the inspected samples in magneto-optical (MO) setups limit the volume available for external magnetic field generation coils. Air or water-cooled copper coils are commonly used for field generation, however these coils usually make it possible to attain limited fields of the order of 10-50 mT, in continuous operating mode. HTS coils offer a unique and cost effective solution in such cases of limited space. A compact, 0.4 T, cryogen-free, HTS magnet has been designed, built and tested in a MO setup. The magnet is made of 3, 100 turns single pancakes, mounted on the second stage of a two-stage cryocooler. The HTS coil operates at about T = 45 K and generates 0.4 T in a warm bore of 30 mm diameter. Minimization of metal components in the coil makes it possible to attain field ramp rates of 7.4 T/sec with a coil charging voltage of 20 V. Initial cool-down time of the magnet takes less than 5 hours. The magnet design and performances are described in detail and serve as an example for solutions that HTS technology may offer in limited space applications.
|Number of pages||4|
|Journal||IEEE Transactions on Applied Superconductivity|
|Issue number||2 PART II|
|State||Published - Jun 2005|
Bibliographical noteFunding Information:
Manuscript received October 5, 2004. This work was supported by the Israeli Ministry of Industry and Commerce under funds. Y. Wolfus, A. Friedman, F. Kopansky, and Y. Yeshurun are with the Department of Physics, Institute of Superconductivity, Bar-Ilan University, Ramat-Gan 52900, Israel (e-mail: email@example.com). Z. Bar-Haim, Z. Ron, and N. Pundak are with RICOR-Cryogenic&Vacuum Systems, En Harod Ihud 18960, Israel (e-mail: firstname.lastname@example.org). Digital Object Identifier 10.1109/TASC.2005.849642 Fig. 1. Typical MO setup including a sample cryostat (1), cold pillar with optical window (2) and polarized microscope with objective wheel (3).
- BSCCO tape
- Cryogen-free magnet
- HTS coil
- Magneto-optical setup