W. Gilbert

Magnetic field decay in model SSC dipoles

LBL-25139 Lawrence Berkeley Laboratory UNIVERSITY OF CALIFORNIA Accelerator & Fusion Research Division Presented at the 1988 Applied Superconductivity Conference, San Francisco, CA, August 21-25, 1988 Magnetic Field Decay in Model sse Dipoles W.S. Gilbert, R.F. Althaus, PJ. Barale, R.W. Benjegerdes, M.A. Green, M.l Green, and R.M. Scanlan August 1988 r Prepared for tbe U.S. Department of Energy under Contract Number DE-AC03-76SF00098.

Tests of full scale SSC R&D dipole magnets

Four full-scale SSC (Superconducting Super Collider) research and development dipole magnets, incorporating successive mechanical design improvements, have been quench-tested. Three of the magnets are heavily instrumented with sensors to measure their mechanical behavior and verify the effectiveness of the mechanical improvements and with multiple voltage taps to locate the origin of quenches. The last two magnets of this series reach the SSC design operating field of 6.6 T in two or fewer quenches. Load cells and motion sensors show that in these two magnets the azimuthal clamping stress is higher at zero current and drops more slowly with excitation that in previous long magnets, and that the axial motion of the coil upon excitation has been greatly reduced. Quenches are found to originate preferentially in several locations, suggesting other design improvements. >

A Nb 3 Sn dipole magnet reacted after winding

A 5 cm bore dia., 1-m-long dipole model magnet was constructed by winding un-reacted cable, followed by reaction and epoxy-impregnation. Experience and test results are described on the 1.7 mm dia. internal-tin wire, the eleven-strand flattened cable, fiberglass insulation, and construction of the magnet. Each half of the magnet has two double-pancake-type windings that were reacted in a single operation. The two double-pancakes were then separately vacuum impregnated after soldering the flexible Nb-Ti leads to the Nb 3 Sn conductors. No iron flux return yoke was used. In initial tests a central field of 8.0 T was reached at 4.4 K. However, evidence from training behavior, and 1.8 K tests indicate that premature quenching, rather than critical current of the cable, limited the field intensity. The magnet was reassembled and more rigidly clamped; additional test results are reported.

Development of a 40 mm bore magnet cross section with high field uniformity for the 6.6T SSC dipole

LBL-21297 Lawrence Berkeley Laboratory UNIVERSITY OF CALIFORNIA Accelerator & Fusion Research Division Presented at the 1986 Applied Superconductivity Conference, Baltimore, MD, September 29-0ctober 3, 1986 DEVELOPMENT OF A 40 mm BORE MAGNET CROSS SECTION WITH HIGH FIELD UNIFORMITY FOR THE 6.6T SSC DIPOLE S, Caspi , W, Gilbert, M, Helm, L.J, Laslett, and C, Taylor September 1986 Prepared for the U.S, Department of Energy under Contract DE-AC03-76SF00098

Tests of prototype SSC magnets

Results are presented from tests of the third full-scale development dipole magnet for the Superconducting Super Collider (SSC) and from a retest of a 4.5-m model magnet of the same design mounted in an SSC cryostat. The 4.5-m magnet showed consistent quench performance between its original tests in boiling liquid helium in a vertical dewar and the current tests in forced-flow helium in a horizontal cryostat. Little or no retraining was observed over several thermal cycles. The full-length magnet required 12 quenches to train to its short-sample limit of 6800 A and displayed a reasonably stable quench plateau following training. Data are presented on quench behavior as a function of current and temperature, and on azimuthal and longitudinal loading of the coil by the support structure. >

The effects of filament magnetization in superconducting magnets as calculated by poisson

Lawrence Berkeley Laboratory UNIVERSITY OF CALIFORNIA Accelerator & Fusion Research Division Presented at the 1986 Applied Superconductivity Conference, Baltimore, MD, September 29·0ctober 3, 1986 THE EFFECTS OF FILAMENT MAGNETIZATION IN SUPERCONDUCTING MAGNETS AS CALCULATED, BY POISSON S, Caspi, W,S, Gilbert, M, Helm, and LJ, Laslett September 1986 Prepared for the U.S. Department of Energy under Contract DE-AC03-76SF00098

Field quality of the end sections of SSC dipoles

LBL-22208 SSC-MAG- \06 SSC- N-250 FIELD QUALITY OF THE END SECTIONS OF SSC DIPOLES· w. V. Hassenzahl, S. Caspi, W. Gilbert, M. Helm, and L. J. Laslett Lawrence Berkeley Laboratory University of California Berkeley, California 94720 G.A. Morgan Brookhaven National Laboratory Upton, Long Island, New York 11973 September 1986 • This work was supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, High Energy Physics Division, U.S. Dept. of Energy, under Contract No. DE-AC03- 76SFOOO98.

Full length prototype SSC dipole test results

Results are presented from tests of the first full length prototype SSC dipole magnet. The cryogenic behavior of the magnet during a slow cooldown to 4.5K and a slow warmup to room temperature has been measured. Magnetic field quality was measured at currents up to 2000 A. Averaged over the body field all harmonics with the exception of b 2 and b 8 are at or within the tolerances specified by the SSC Central Design Group. (The values of b 2 and b 8 result from known design and construction defects which will be corrected in later magnets.) Using an NMR probe the average body field strength is measured to be 10.283 G/A with point to point variations on the order of one part in 1000. Data are presented on quench behavior of the magnet up to 3500 A (approximately 55% of full field) including longitudinal and transverse velocities for the first 250 msec of the quench.

Magnetic measurement system for harmonic analysis of LBL SSC model dipoles and quadrupoles

Specialized hardware and software developed to facilitate harmonic error analysis measurements of 1-m long Superconducting Super Collider model dipole and quadrupole magnets are described. Cold bore measurements feature cryogenic search-coil arrays with high bucking ratios that also have sufficient sensitivity to make room-temperature measurements at the low magnet currents of approximately 10 A. Three sets of search coils allow measurements of the center, either end, and/or the axially integrated field. Signals from the search coils are digitally integrated by a voltage-to-frequency converter feeding an up-down counter. The data are drift-corrected, Fourier analyzed, converted to physical quantities, and printed and plotted. A cycle of measurements including data acquisition, processing, and the generation of tabular and graphic output requires 80 s. The vast amount of data generated (several hundred measurement cycles for each magnet) has led to the development of three types of postprocessing for the dipole and quadrupole systems: (1) re-creation of the real-time output, (2) generation of an SSC prompt report, and (3) production of general-purpose spreadsheet/graphical output. >

Design of epoxy-free superconducting dipole magnets and performance in both Helium I and pressurized Helium II

LBL-12455 | H 1 Lawrence Berkeley Laboratory K J UNIVERSITY OF CALIFORNIA Accelerator & Fusion Research Division P r e s e n t e d a t t h e V l l t h I n t e r n a t i o n a l Conference on Magnet Technology, K a r l s r u h e , Germany, March 3 0 - A p r l l 3 , 1981 DESIGN OF EPOXY-FREE SUPERCONDUCTING DIPOLE MAGNETS AND PERFORMANCE IN BOTH HELIUM I AND PRESSURIZED HELIUM II C. Taylor, R. Althaus, S. Caspi, W. Gilbert, W. Hassenzahl, R. Meuser, J. Rechen, and R. Warren March 1S81 H T B n W O T I M » K T IS UIUMIIHI S m i a F H S Prepared for the U.S. Department ot Energy under Contract W-7405-ENG-48