Title :
Compact HTS cryogen-free magnet for magneto-optics research setup
Author :
Wolfus, Y. ; Friedman, A. ; Kopansky, F. ; Yeshurun, Y. ; Bar-Haim, Z. ; Ron, Z. ; Pundak, N.
Author_Institution :
Dept. of Phys., Bar-Ilan Univ., Ramat-Gan, Israel
fDate :
6/1/2005 12:00:00 AM
Abstract :
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.
Keywords :
cryogenics; high-temperature superconductors; magneto-optical devices; superconducting magnets; compact HTS cryogen-free magnet; external magnetic field generation coils; magneto-optics research; Boring; Coils; Copper; Costs; High temperature superconductors; Lenses; Magnetic fields; Magnetooptic effects; Space technology; Testing; BSCCO tape; HTS coil; cryogen-free magnet; magneto-optical setup;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2005.849642