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Correlation between Strand Stability and Magnet Performance (open access)

Correlation between Strand Stability and Magnet Performance

Magnet programs at BNL, LBNL and FNAL have observed instabilities in high J{sub c} Nb{sub 3}Sn strands and magnets made from these strands. This paper correlates the strand stability determined from a short sample-strand test to the observed magnet performance. It has been observed that strands that carry high currents at high fields (greater than 10T) cannot sustain these same currents at low fields (1-3T) when the sample current is fixed and the magnetic field is ramped. This suggests that the present generation of strand is susceptible to flux jumps (FJ). To prevent flux jumps from limiting stand performance, one must accommodate the energy released during a flux jump. To better understand FJ this work has focused on wire with a given sub-element diameter and shows that one can significantly improve stability by increasing the copper conductivity (higher residual resistivity ratio, RRR, of the Cu). This increased stability significantly improves the conductor performance and permits it to carry more current.
Date: April 16, 2005
Creator: Dietderich, Daniel R.; Bartlett, Scott E.; Caspi, Shlomo; Ferracin, Paolo; G ourlay, Stephen A.; Higley, Hugh C. et al.
Object Type: Article
System: The UNT Digital Library
[Funeral Program for Mildred Marie Walker Gilmore, April 16, 2005] (open access)

[Funeral Program for Mildred Marie Walker Gilmore, April 16, 2005]

Funeral program for Mrs. Mildred Marie Walker Gilmore "Millie", born June 4, 1911 and died April 10, 2005. The funeral was held April 16, 2005 at West End Baptist Church, officiated by Dr. A. Bernard Devers, I. The funeral arrangements were made through Sutton-Sutton Mortuary, Inc. and she was buried in Meadowlawn Memorial Park in San Antonio, Texas.
Date: April 16, 2005
Creator: unknown
Object Type: Pamphlet
System: The Portal to Texas History
Structure for an LHC 90mm Nb3Sn Quadrupole Magnet (open access)

Structure for an LHC 90mm Nb3Sn Quadrupole Magnet

A full-scale mechanical model of the LHC Nb{sub 3}Sn quadrupole magnet structure has been designed, built and tested. The structure will support a 90mm bore, 1m long magnet prototype as part of the US LHC Accelerator Research Program (LARP). The structure utilizes Bladder and Key Technology to control and transfer pre-stress from an outer aluminum shell to an inner coil. Axial aluminum rods take care of pre-stress at the ends--ensuring that the coil is fully constrained along all three axes. The outer aluminum shell and an inner ''dummy coil'' (aluminum tube) were extensively instrumented with strain gauges. The gauges were used to monitor and map the effectiveness of the stress relation between the loading structure and a ''dummy'' coil through varying mechanical load conditions --from bladder and key pre-stress at room temperature through cool-down. Test results of the stress distribution in the structure and the in dummy coil is reported and compared with expected results calculated with the structural analysis program ANSYS.
Date: April 16, 2005
Creator: Hafalia, A. R.; Caspi, S.; Bartlett, S. E.; Dietderich, D. R.; Ferracin, P.; Gourlay, S. A. et al.
Object Type: Article
System: The UNT Digital Library
Future Accelerator Magnet Needs (open access)

Future Accelerator Magnet Needs

None
Date: April 16, 2005
Creator: Devred, Arnaud; Gourlay, Stephen A. & Yamamoto, Akira
Object Type: Article
System: The UNT Digital Library
Measured Strain of Nb3Sn Coils During Excitation and Quench (open access)

Measured Strain of Nb3Sn Coils During Excitation and Quench

The strain in a high field Nb{sub 3}Sn coil was measured during magnet assembly, cool-down, excitation and spot heater quenches. Strain was measured with a full bridge strain gauge mounted directly over the turns and impregnated with the coil. Two such coils were placed in a ''common coil'' fashion capable of reaching 11T at 4.2K. The measured steady state strain in the coil is compared with results obtained using the FEM code ANSYS. During quenches, the transient strain (due to temperature rise) was also measured and compared with the calculated mechanical time response to a quench.
Date: April 16, 2005
Creator: Caspi, S.; Bartlett, S. E.; Dietderich, D. R.; Ferracin, P.; Gourlay, S. A.; Hannaford, C. R. et al.
Object Type: Article
System: The UNT Digital Library
Test Results of HD1b, an upgraded 16 Tesla Nb3Sn Dipole Magnet (open access)

Test Results of HD1b, an upgraded 16 Tesla Nb3Sn Dipole Magnet

The Superconducting Magnet Group at Lawrence Berkeley National Laboratory has been developing high-field, brittle-superconductor, accelerator magnet technology, in which the conductor's support system can significantly impact conductor performance (as well as magnet training). A recent H-dipole coil test (HD1) achieved a peak bore-field of 16 Tesla, using two, flat-racetrack, double-layer Nb{sub 3}Sn coils. However, its 4.5 K training was slow, with an erratic plateau at {approx}92% of its un-degraded ''short-sample'' expectation ({approx}16.6 T). Quench-origins correlated with regions where low conductor pre-stress had been expected (3-D FEM predictions and variations in 300 K coil-size). The coils were re-assembled with minor coil-support changes and re-tested as ''HD1b'', with a 185 MPa average pre-stress (30 MPa higher than HD1, with a 15-20 MPa pole-turn margin expected at 17 T). Training started higher (15.1 T), and quickly reached a stable, negligibly higher plateau at 16 T. After a thermal cycle, training started at 15.4 T, but peaked at 15.8 T, on the third attempt, before degrading to a 15.7 T plateau. The temperature dependence of this plateau was explored in a sub-atmospheric LHe bath to 3.0 K. Magnet performance data for both thermal cycles is presented and discussed, along with issues for future high-field …
Date: April 16, 2005
Creator: Lietzke, A. F.; Bartlett, S. E.; Bish, P.; Caspi, S.; Dietderich, D.; Ferracin, P. et al.
Object Type: Article
System: The UNT Digital Library
Oral History Interview with Mary Burkett, April 16, 2005 (open access)

Oral History Interview with Mary Burkett, April 16, 2005

The National Museum of the Pacific War presents an interview with Mary Burkett. Burkett completed psychiatry and nurse training at Indianapolis City Hospital in February of 1940. She volunteered and entered the Army in October of 1943. She was assigned to Ashford General Hospital in White Sulphur Springs, West Virginia. She was assigned to five different wards in the hospital and was assigned to care for the patients. She provides some detail of her experiences working on the neuro-psychiatric floor, and shares stories of some of her patients. She completed additional training at Fort Knox, Kentucky. She traveled on the USS Matsonia (ID-1589) to the South Pacific, and she provides some detail of her travels.
Date: April 16, 2005
Creator: Burkett, Mary
Object Type: Text
System: The Portal to Texas History
The Baytown Sun (Baytown, Tex.), Vol. 84, No. 133, Ed. 1 Saturday, April 16, 2005 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 84, No. 133, Ed. 1 Saturday, April 16, 2005

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: April 16, 2005
Creator: Cash, Wanda Garner
Object Type: Newspaper
System: The Portal to Texas History
Perry Daily Journal (Perry, Okla.), Vol. 112, No. 75, Ed. 1 Saturday, April 16, 2005 (open access)

Perry Daily Journal (Perry, Okla.), Vol. 112, No. 75, Ed. 1 Saturday, April 16, 2005

Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.
Date: April 16, 2005
Creator: Brown, Gloria
Object Type: Newspaper
System: The Gateway to Oklahoma History