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in subjects: "420201 -- Engineering-- Cryogenic Equipment & Devices"

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Self-correction coil: operation mechanism of self-correction coil

We discuss here the operation mechanism of self-correction coil with a simple model. At the first stage, for the ideal self-correction coil case we calculate the self-inductance L of self-correction coil, the mutual inductance M between the error field coil and the self-correction coil, and using the model the induced curent in the self-correction coil by the external magnetic error field and induced magnetic field by the self-correction coil. And at the second stage, we extend this calculation… more

Date: June 1, 1983

Creator: Hosoyama, K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Construction and testing of the two meter diameter TPC thin superconducting solenoid

High energy colliding beam physics often requires large detectors which contain large volumes of magnetic field. The TPC (Time Projection Chamber) experiment at PEP will use a 1.5T magnetic field within a cylindrical volume which is 2.04m in diameter bounded by iron poles which are separated by a gap of 3.25m. The TPC magnet, built in 1979 by the Lawrence Berkeley Laboratory (LBL), is the largest high current density superconducting magnet built to date. It is designed to operate at a current d… more

Date: August 1, 1979

Creator: Green, M. A.; Eberhard, P. H.; Ross, R. R. & Taylor, J. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Application of superconducting coils to VAR control in electric power systems: a proposal

During the last eight years, static VAR-control systems with thyristor-controlled, room-temperature reactors have been used in electrical systems for voltage control and system stabilization. In this proposal, we describe a new static VAR-control system that uses an asymmetrically controlled Graetz bridge and a superconducting dc coil. Preliminary studies indicate that the proposed system will have lower overall losses and that its capital cost and electrical characteristics are comparable to t… more

Date: November 1, 1979

Creator: Boenig, H. J. & Hassenzahl, W. V.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Analysis of cooldown performance for ISABELLE helium refrigerator

The ISABELLE refrigerator was designed to provide cooling for 1000 superconducting magnets. It has the dual duty of providing cooling at steady-state operating conditions and to cooldown massive magnets from ambient temperature. During the cooldown, tremendous quantities of heat (approx. 4.8 x 10/sup 11/ J) must be removed from the magnets (5.9 x 10/sup 9/ gm of iron) and 75,000 liters of cold helium must be supplied to fill the system. In the planning for ISABELLE, this procedure has been esti… more

Date: January 1, 1981

Creator: Wu, K. C.; Brown, D. P. & Moore, R. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Flux jumps in a pinch

This paper discusses flux jumps, using solid-state physics. The forces on the outermost leptons due to the current flowing through the metal are small compared with the forces in the interatomic environment. The processing of NbTi used in superconducting cables creates defects that pin magnetic flux lines. If one of these pinning sites lets its flux line go, it starts a positive feedback event known as ''flux jump''. The heat generated can be conducted away before the material goes normal if th… more

Date: July 1, 1987

Creator: Kuchnir, M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Cycle design for the ISABELLE helium refrigerator

The superconducting magnets for the ISABELLE storage ring/accelerator are designed to be operated at 3.8/sup 0/K using a forced-flow supercritical helium cooling system. The ISABELLE refrigerator has been designed subject to these special requirements. The design output is 13.65 KW of refrigeration below 4.2/sup 0/K (for cooling the magnet and distribution system), 55 KW at 55/sup 0/K (to cool heat shields for the whole system) and 100 g/s of liquefaction (for magnet power leads cooling). The s… more

Date: January 1, 1981

Creator: Brown, D. P.; Schlafke, A. P.; Wu, K. C. & Moore, R. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Stress relaxation studies of CBA and SSC coil sections

Instrumented fixtures were built to measure coil assembly stress and relaxation rates in samples of CBA and SSC coil sections. The effects of constant temperature and thermal cycling on short and long term relaxation are presented. Conclusions and suggestions are presented to achieve minimum long term stress relaxation during the assembly and installation of the SSC rings. 5 refs., 5 figs., 3 tabs.

Date: January 1, 1985

Creator: Anerella, M.; Hoffman, A.; Jackimowicz, R.; Lenz, W.; Skaritka, J. & Tuttle, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Fermilab satellite refrigerator compressors with the oil- and moisture-removal systems

We have designed and tested a helium purification system for the Energy Doubler and the experimental areas. A purification system is installed after each screw compressor in the satellite refrigerators. The purification system removes oil mist, oil vapor, water vapor, and particulate from the compressed helium. The units were designed with consideration of modularity and necessary redundancy (i.e., guard purification). Test results which led to the final configuration are presented, along with … more

Date: August 1, 1983

Creator: Satti, J. A. & Andrews, R. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Noise limitations of the DC SQUID

The dc SQUID (Superconducting Quantum Interference Device) is a very sensitive detector of changes in magnetic flux, and is becoming widely used as a magnetometer and as a voltmeter. The paper summarizes the noise limitations of the device and makes projections of its ultimate performance. A more detailed account of the work is to appear elsewhere.

Date: July 1, 1978

Creator: Clarke, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Magnetization measurements on multifilamentary Nb/sub 3/Sn and NbTi conductors

The effective filament size has been determined for a number of high current Nb/sub 3/Sn multifilamentary composites. In most cases it is much larger than the nominal filament size. For the smallest filaments (approx. 1 micron) the effective size can be as much as a factor of forty times the nominal size. Samples made by the internal tin, bronze route, and jelly roll methods have been examined with filaments in the range one to ten microns. Rate dependent magnetization and flux jumping have bee… more

Date: January 1, 1984

Creator: Ghosh, A. K.; Robins, K. E. & Sampson, W. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Superconducting magnetic energy storage

Recent programmatic developments in Superconducting Magnetic Energy Storage (SMES) have prompted renewed and widespread interest in this field. In mid 1987 the Defense Nuclear Agency, acting for the Strategic Defense Initiative Office, issued a request for proposals for the design and construction of SMES Engineering Test Model (ETM). Two teams, one led by Bechtel and the other by Ebasco, are now engaged in the first phase of the development of a 10 to 20 MWhr ETM. This report presents the rati… more

Date: August 1, 1988

Creator: Hassenzahl, W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The high field superconducting magnet program at LLNL: Annual report

In FY 86 the program continued along several interrelated thrust areas. These thrust areas have been broadly labeled as follows: (1) Superconductor Research and Technology; (2) Magnet Systems Materials Technology; (3) Magnet Systems Design Technology; (4) High Field Test Facility; and (5) Technology Transfer.

Date: December 1, 1986

Creator: Miller, J. R.; Chaplin, M. R.; Kerns, J. A.; Leber, R. L.; Rosdahl, A. R.; Slack, D. S. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Computer-based data acquisition system in the Large Coil Test Facility

The utilization of computers for data acquisition and control is of paramount importance on large-scale fusion experiments because they feature the ability to acquire data from a large number of sensors at various sample rates and provide for flexible data interpretation, presentation, reduction, and analysis. In the Large Coil Test Facility (LCTF) a Digital Equipment Corporation (DEC) PDP-11/60 host computer with the DEC RSX-11M operating system coordinates the activities of five DEC LSI-11/23… more

Date: January 1, 1983

Creator: Gould, S.S.; Layman, L.R. & Million, D.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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SSWL and BWL: finite element models of compressed magnetic field current generators

Documentation is presented for two new computer codes modeling the behavior of compressed magnetic field current generators. Code output results for the typical generator configurations are presented and compared to experimental results. (auth)

Date: January 1, 1976

Creator: Tucker, T. J. & Leeman, J. E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Items from the construction of ESCAR

ESCAR is an experimental superconducting accelerator which is being built at Lawrence Berkeley Laboratory to gain timely, full-scale experience in the construction and operation of a fully cryogenic accelerator. A report is given of the construction of several non-conventional items.

Date: March 16, 1977

Creator: Byrns, R. A.; Gilbert, W. S.; Lambertson, G. R.; Meuser, R. B. & Rechen, J. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Effect of Parasitic Refrigeration on the Efficiency of Magnetic Liquefiers

Our studies have shown that magnetic refrigerators have the potential to liquefy cryogens very efficiently. High efficiency is especially important for liquid hydrogen and natural gas applications where the liquefaction costs are a significant fraction of the total liquid cost. One of the characteristics of magnetic refrigerators is the requirement for a high-field superconducting magnet. Providing a 4.2-K bath for this magnet will require a small amount of parasitic refrigeration at 4.2 K even… more

Date: January 1, 1982

Creator: Barclay, J. A. & Stewart, W. F.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Conceptual design of a superconducting solenoid for a magnetic SSC (Superconducting Super Collider) detector

The conceptual design of a large superconducting solenoid suitable for a magnetic detector at the Superconducting Super Collider (SSC) has begun at Fermilab. The magnet will provide a magnetic field of 2 T over a volume 8 m in diameter by 16 m long. The particle-physics calorimetry will be inside the field volume and so the coil will be bath cooled and cryostable; the vessels will be stainless steel. Predictibility of performance and the ability to safely negotiate all probable failure modes, i… more

Date: July 1, 1988

Creator: Fast, R. W.; Grimson, J. H.; Kephart, R. D.; Krebs, H. J.; Stone, M. E.; Theriot, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Design of a 28 MW pulse facility for testing superconducting coils to several hundred megajoules capacity

Railway traction motors are available in unit sizes convenient for installation and series-parallel grouping. They are rugged. Industry builds and refurbishes them with good economy and in quantities replenishing the rolling stock. We find them well suited for reversing the current in a superconducting winding. We focus on a pulsed energy of 20 to 100 MJ, discussing our analysis and facility planning. Limitations are imposed by the following maximum numbers tolerated by the motor - pulsed curre… more

Date: January 1, 1980

Creator: Vogel, H.F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Magnetic field decay in model SSC dipoles

We have observed that some of our model SSC dipoles have long time constant decays of the magnetic field harmonics with amplitudes large enough to result in significant beam loss, if they are not corrected. The magnets were run at constant current at the SSC injection field level of 0.3 tesla for one to three hours and changes in the magnetic field were observed. One explanation for the observed field decay is time dependent superconductor magnetization. Another explanation involves flux creep … more

Date: August 1, 1988

Creator: Gilbert, W. S.; Althaus, R. F.; Barale, P. J.; Benjegerdes, R. W.; Green, M. A.; Green, M. I. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Technical report on manufacture of Nb/sub 3/Sn superconducting wire by cold hydrostatic extrusion

Results indicate that the superconducting properties of Nb/sub 3/Sn wires could be improved by the use of hydrostatic extrusion. Billets with varying ratio of core to sleeve radius are being hydrostatically extruded and will be tested. The measured data will be compared with conventionally drawn wires.

Date: January 1, 1979

Creator: Avitzur, B.; Chou, Y.T.; Thadani, V. & Luhman, T.S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Wire rope superconducting cable for diurnal load leveling SMES

The design of a wire rope cable for a superconducting magnetic energy storage (SMES) unit is discussed. The superconducting wires in the rope permit the passage of large currents in the relatively small conductors of the windings and hence cause large electromagnetic forces to act on the rope. The diameter of the rope, from a strength point of view, can be considerably reduced by supporting the rope at various points along its length.

Date: January 1, 1980

Creator: Costello, G.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Direct laser/materials interaction: Laser ablation of superconductor materials and laser welding

This paper considers two applications of direct laser/materials interaction, laser ablation of superconductor materials and Nd-YAG laser welding. The laser ablation experiments with 355 nm, 10 ns pulses have demonstrated uniform, thin superconductor films. The film uniformity was improved significantly be rotating both the laser target and the film support, and by vertically dithering the laser focus. The film stoichiometry does vary with laser fluence, but it is within 10% of the target materi… more

Date: January 1, 1989

Creator: Cremers, D. A.; Dixon, R. D.; Estler, R. C.; Lewis, G. K.; Lyman, J. L.; Muenchausen, R. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Short circuit detection in the winding and operation of superconducting magnets

Three categories of shorts will be discussed: (1) shorts to the metallic bobbin or other structural elements, (2) shorts between turns caused by instrumentation wires that are deliberately connected to a turn at the end (e.g., voltage taps) and that short out to another turn but are not completely severed in the process, and (3) short circuits between turns caused by direct contact due to insulation failure by chips of metal bridging turns and by instrumentation wires that bridge turns but are … more

Date: January 1, 1982

Creator: Walstrom, P.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Stability in accelerator dipoles in He I and He II

Several epoxy-free magnets of 76 and 130 mm diameter have been constructed and tested at Lawrence Berkeley Laboratory. This report describes results of tests at 1.8 and 4.4 K on two recently completed magnets and presents some earlier data on heater induced quenches also at 1.8 and 4.4 K.

Date: November 1, 1981

Creator: Hassenzahl, W.; Gilbert, W.; Taylor, C.; Caspi, S.; Rechen, J. & Meuser, R.

Item Type: Article

Partner: UNT Libraries Government Documents Department