Magnetic shielding properties have been investigated using Hall
plates at 4.2 K in a parallel magnetic field up to 4 T for
superconducting cylinders with and without a bottom, which are
multilayer composites consisting of NbTi, Nb, and Cu. These composite
cylinders were fabricated by deep drawing a multilayer composite sheet
made by cladding and rolling. It was found that a sample of five
concentrically stacked cup-shaped cylinders, with a thickness of 1 mm,
an inside diameter of 20-40 mm, and a length of 45 mm, can reduce the
external magnetic field of 3 T to less than 10 G
"But the shell is made of pure iron in order to have satisfying magnetic performance at high field. For requirement 4, a cylindrical superconducting magnetic shield ensures efficiency up to 100 % at 4.2 K, for background fields up to few T. In particular, a NbTi/Nb/Cu multilayer composite  and a bulk of MgB 2  are considered. In this way, a superconducting shield of thickness 6 mm is capable of screening up to 1 T  leaving the design of the iron shell concerned only with the off-centering issue. "
[Show abstract][Hide abstract] ABSTRACT: The design of a cryogenic sensing element for superconducting DC current transformers working up to 100 kA at 4.2 K is proposed. Limitations of μ-metal magnetic characteristics at cryogenic conditions are overcome by a soft Ni 81-Mo 5-Fe magnetic alloy (referred to as cryogenic permalloy). An optimized geometrical design allows cores saturation due to mechanical constraints to be avoided. The effectiveness of the design is demonstrated through electromagnetic simulations exploiting measurement results from the characterization of cryogenic permalloy samples. Moreover, a preliminary lab-scale cryogenic DCCT prototype for a nominal current of 20 kA is implemented and characterized. A typical precision of the transducer below ±0.05% is achieved along with nonlinearity better than ±0.05%.
Journal of Instrumentation 02/2014; 9(03). DOI:10.1088/1748-0221/9/03/P03011 · 1.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The muon g-2 experiment (E821) at the AGS requires a precision in
the magnetic field over muon orbit at the level of 0.1 ppm. Injection is
done with a superconducting inflector involving a double cosine theta
winding approximately cancels its fringe field. Nevertheless its
residual field would effect the homogeneity of the storage ring magnetic
field. A method of using a superconducting sheet surrounding the
inflector to further reduce the fringe field is being investigated. The
experimental program to explore this technique is described and some
test results are presented
Particle Accelerator Conference, 1993., Proceedings of the 1993; 06/1993
[Show abstract][Hide abstract] ABSTRACT: Magnetic shielding from alternating magnetic field by a NbTi/Nb/Cu superconducting multilayer composite cylinder was investigated at liquid-helium temperatures. The specimen employed in this study was a slender seamless cylinder about 15 mm in diameter and having an aspect ratio of 6. The frequency of the alternating magnetic field was in the range of 40–500 Hz, and the maximum amplitude was 1000 G rms at 40 and 50 Hz owing to the capacity of the ac generator. The magnetic shielding efficiency of this cylinder, defined as the ratio of the magnetic field strength with and without the cylinder, was found to be of the order of 10−4. It was also found that the magnetic shielding effect depends upon the frequency investigated in this study. These shielding effects were mainly due to the shielding current originating from the superconductivity, which turned out to give superior shielding effect than that of a Cu cylinder.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.