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M. Majoros,
M.D. Sumption,
M.A. Susner,
S. Bhartiya,
M. Mahmud,
E.W. Collings,
M. Tomsic,
M. Rindfleisch, J. Phillips,
D. Lyons,
J. Yue
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ABSTRACT: A model helical undulator 250 mm in length, with a period of 14 mm, was designed, fabricated and tested. The helical coil was wound with multifilamentary, internal-Sn type Nba<sub>3</sub>Sn strand. The 0.7 mm OD strand was insulated with S-glass, wound onto the former, and reacted, after which the coil underwent vacuum epoxy impregnation. The beam aperture was 7 mm, the winding bore diameter was 8 mm, and the OD of the complete winding was 18 mm. The helical poles were made from 1016 low carbon steel, and projected slightly above the coil pack, with an OD of 19.06 mm. The coil I<sub>c</sub> and the magnetic field in the bore were measured at 4.2 K in a liquid helium bath. The bore field was also measured as a function of position along the length of the undulator.
IEEE Transactions on Appiled Superconductivity 07/2010; · 1.04 Impact Factor
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M. Majoros,
M.D. Sumption,
M.A. Susner,
S. Bhartiya,
S.D. Bohnenstiehl,
E.W. Collings,
M. Tomsic,
M. Rindfleisch, J. Phillips,
D. Lyons,
J. Yue
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ABSTRACT: A short model helical undulator, 250 mm long, with a period of 14 mm was designed, fabricated and then subsequently tested in a liquid helium bath. The helical coil was wound with stabilized multi-filamentary MgB<sub>2</sub> strand, 0.5 mm in diameter, in a wind and react mode with S-glass insulation followed by vacuum epoxy impregnation. Beam aperture of the coil was 7 mm, winding bore diameter 8 mm, coil winding OD=18 mm and the 1010 Fe pole (flange) has an OD=19.05 mm. The coil was measured for I <sub>c</sub> and magnetic field in the bore at 4.2 K in a liquid helium bath. The bore field as a function of depth was also determined near the critical current at 4.2 K. The load line of the coil was compared to short sample I <sub>c</sub> values.
IEEE Transactions on Appiled Superconductivity 07/2009; · 1.04 Impact Factor
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ABSTRACT: Multifllamentary MgB<sub>2</sub> wire was used to construct three coils that were tested for transport J<sub>c</sub> and magnetic field in the bore between 4.2 K and 30 K. The solenoid coil achieved 85 A at 4.2 K with 3.9 T in a 3.8 cm bore. A racetrack coil was also fabricated with an attached compression plate to test the effects of compressive stress on an MgB<sub>2</sub> racetrack coil. At compressive stresses up to 52 MPa, no degradation was observed in transport J<sub>c</sub> at 20 K. A react and wind coil with a 56 cm bore and 828 m of MgB<sub>2</sub> wire was also tested for transport J<sub>c</sub> and magnetic field in the bore to demonstrate the feasibility of the react and wind process. At 5 K, the react and wind coil achieved 168 A and 0.17 T.
IEEE Transactions on Appiled Superconductivity 07/2007; · 1.04 Impact Factor
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ABSTRACT: A racetrack coil using MgB<sub>2</sub>/Cu strand has been fabricated and tested for transport current density at 4.2 K in self field. The monofilamentary strand was 1.0 mm OD and insulated with S-glass braid. Eighty turns of strand (42 m) were wound onto a stainless steel former with outer dimensions 25 cm×10 cm×0.86 cm. The resulting racetrack coil was heat treated at 675°C for 30 minutes in flowing Ar. The strand, with a superconducting fraction of 26%, occupied 49% of the total coil pack cross sectional area. The coil I<sub>c</sub> at 4.2 K and self field was 120 A (using a 1 μV/cm criterion). This led to a J<sub>c,sc</sub> (across the whole coil) of 6.12×10<sup>4</sup> A/cm<sup>2</sup>, a J<sub>e</sub> in the wire of 1.59×10<sup>4</sup> A/cm<sup>2</sup>, and an overall winding J<sub>e</sub> of 7.9×10<sup>3</sup> A/cm<sup>2</sup> at 4.2 K in self field. The n-values ranged from 17 to 56.
IEEE Transactions on Appiled Superconductivity 07/2005; · 1.04 Impact Factor
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ABSTRACT: Three solenoids have been wound and with MgB2 strand and tested for transport properties. One of the coils was wound with Cu-sheathed monofilamentary strand and the other two with a seven filament strand with Nb-reaction barriers, Cu stabilization, and an outer monel sheath. The wires were first S-glass insulated, then wound onto an OFHC Cu former. The coils were then heat treated at 675C/30 min (monofilamentary strand) and 700C/20 min (multifilamentary strand). Smaller (1 m) segments of representative strand were also wound into barrel-form samples and HT along with the coils. After HT the coils were epoxy impregnated. Transport Jc measurements were performed at various taps along the coil lengths. Measurements were made initially in liquid helium, and then as a function of temperature up to 30 K. Homogeneity of response along the coils was investigated and a comparison to the short sample results was made. Each coil contained more than 100 m of 0.84-1.01 mm OD strand. One of the 7 strand coils reached 222 A at 4.2 K, self field, with a Jc of 300 kA/cm2 in the SC and a winding pack Je of 23 kA/cm2. At 20 K these values were 175 kA/cm2 and 13.4 kA/cm2. Magnet bore fields of 1.5 T and 0.87 T were achieved at 4.2 K and 20 K, respectively. The other multifilamentary coil gave similar results. Comment: 22 pages, 8 figures, 2 tables
03/2005;
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ABSTRACT: A racetrack coil using MgB2/Cu strand has been fabricated and tested for transport current density at 4.2 K in self field. The monofilamentary strand was 1.0 mm OD and insulated with S-glass braid. Eighty turns of strand (42 m) were wound onto a stainless steel former with outer dimensions 25 cm x 10 cm x 0.86 cm. The resulting racetrack coil was heat treated at 675C for 30 minutes in flowing Ar. The strand, with a superconducting fraction of 26%, occupied 49% of the total coil pack cross sectional area. The coil Ic at 4.2 K and self field was 120 A (using a 1 microvolt/cm criterion). This led to a Jc,sc (across the whole coil) of 6.12 x 10^4 A/cm2, a Je in the wire of 1.59 x 10^4 A/cm2, and an overall winding Je of 7.9 x 10^3 A/cm2 at 4.2 K in self field. The n-values ranged from 17 to 56.
11/2004;
