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Development of niobium spoke cavities for a superconducting light-ion Linac.

Description: This paper reports the development of 350 MHz niobium superconducting cavities for the velocity range 0.2< v/c <0.6. Such cavities could be used to form a linac of exceptional flexibility, capable of efficiently accelerating beams of either protons, deuterons, or any of a wide range of light ions, at intensities sufficient for a production beam for a radioactive beam facility. Results of numerical modeling for several resonator geometries are presented. The design and construction status … more
Date: November 18, 1998
Creator: Shepard, K. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Fast superconducting kicker magnet. Final technical report, November 1994--October 1997

Description: Fast kicker magnets are needed in accelerators to deflect the beam out of the storage ring and into experimental targets and beam dumps. The work reported here is on a new type of fast kicker magnet. The basic idea is to transport the beam along the axis of a tube made of Type I superconductor. An ordinary magnet is used to create a field, B{sub o} perpendicular to the axis of the tube. If B{sub o}<B{sub c}, where B{sub c} is the critical field of the superconductor, the tube remains in the sup… more
Date: May 1, 1998
Creator: Weinstein, R. & Mahale, N.K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Gaertnner LINAC Laboratory report to the cross section working group at National Nuclear Data Center, Brookhaven National Laboratory

Description: The Gaerttner LINAC Laboratory has made neutron transmission and capture measurements up to several hundred eV on samples of Zr, Nb, Mo, Sm, Nd, Ho, Er, Tm, Hf, and W. A new neutron time-of-flight target has been built and installed and a new {sup 6}Li glass transmission detector is under construction. The electron linear accelerator is being refurbished with new klystrons, a new RF transport system and the reinstallation of the ninth accelerating section. These improvements are intended to pro… more
Date: October 1, 1998
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Process optimization for advanced high conductivity-high strength materials

Description: On the basis of investigations carried out earlier, two types of high strength-high conductivity Cu-Nb wires have been designed and appropriate manufacturing processes have been proposed and experimentally approved. Long length conductors with rectangular cross sections 4 x 6 mm{sup 2} and 2 x 3 mm{sup 2} have been fabricated by the in situ process and by the bundle and deform process, which eliminates the operation of melting, accordingly. Investigation on the microstructure of both types of t… more
Date: September 1, 1998
Creator: Pantsyrnyi, V.; Shikov, A. & Nikulin, A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Progress of APT Superconducting LINAC Engineering Development

Description: The authors initiated a program to develop superconducting (SC) RF for high-power proton linacs. These linacs are useful in accelerator-driven transmutation technologies and the Accelerator Production of Tritium (APT) Project. They are developing multicell niobium cavities with elliptical-cell shapes at 700 MHz. These cavities, unlike most elliptical cavities for electron accelerators, are designed to accelerate protons at {beta}<1. Coaxial power couplers are being developed to transmit high (2… more
Date: December 31, 1998
Creator: Chan, K. C. D.; Campbell, B. M.; Gentzlinger, R. C.; Balleyguier, P.; Waynert, J. A.; Haynes, W. B. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The effect of microstructure and temperature on the oxidation behavior of two-phase Cr-Cr{sub 2}X (X = Nb, Ta) alloys

Description: The oxidation behavior of Cr(X) solid solution (Cr{sub ss}) and Cr{sub 2}X Laves phases (X = Nb, Ta) was studied individually and in combination at 950--1,100 C in air. The Cr{sub ss} phase was significantly more oxidation resistant than the Cr{sub 2}X Laves phase. At 950 C, two-phase alloys of Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Ta exhibited in-situ internal oxidation, in which remnants of the Cr{sub 2}X Laves phase were incorporated into a growing chromia scale. At 1,100 C, the Cr-Cr{sub 2}Nb allo… more
Date: November 1, 1998
Creator: Brady, M.P. & Tortorelli, P.F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The hot workability and superplasticity of Ti-48Al-2Nb-2Cr alloys

Description: The hot compression behavior and microstructure evolution of ingot metallurgy (I/M) and powder metallurgy (P/M) processed samples of the near-{gamma} Ti-aluminide alloy, Ti-48Al-2Nb-2Cr (at%), were determined. Three I/M conditions and two P/M conditions were examined in this study. Hot compression tests were performed in the temperature range 1,100--1,300 C at strain rates ranging from 1.67 {times} 10{sup {minus}1}/sec to 1.67 {times} 10{sup {minus}4}/sec. P/M materials consolidated by either h… more
Date: February 1, 1998
Creator: Fuchs, G.E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Nb{sub 3}Sn magnets for a muon collider

Description: High field dipole and quadrupole magnet designs with racetrack coils are investigated. The design option is particularly attractive for a muon collider dipole magnet using the Nb{sub 3}Sn superconductor. A conceptual design of {approximately}15 T single aperture dipole magnet is presented where the coils maintain a simple 2-d structure through the ends. The use of racetrack coils in quadrupole magnets is also discussed. It appears that the racetrack coils are less attractive for high gradient q… more
Date: July 1998
Creator: Gupta, R. C.; Green, M. A.; Scanlan, R. M. & Palmer, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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EOS, thermodynamic, and structural-mechanical properties of intermetallic compounds

Description: This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Several classes of binary intermetallic compounds have important potential application as high temperature structural materials because of their high melting temperature, low density, and high strength, but their use is limited by their poor low temperature ductility and fracture toughness. The goal of this project was to further the development of tech… more
Date: December 31, 1998
Creator: Wills, J. M.; Straub, G. & Albers, R. C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Stainless steels with improved strength for service at 760 C and above

Description: An evaluation was undertaken of modified 25Cr-20Ni stainless steels and a modified 20Cr-25Ni-Nb stainless steel for advanced energy applications at 760 C (1,400 F) and higher. It was found that good fabricability, strength, and ductility could be produced in the modified steels. Stress rupture data to beyond 10,000 h showed that the strengths of the modified steels were more than double that for type 310H stainless steel.
Date: March 1, 1998
Creator: Swindeman, R.W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Study of the potential use of carburized niobium in plutonium processing

Description: Carburized refractory metals, especially tantalum, have been shown to possess properties useful for application as hardware in the plutonium-processing environment. These applications are driven in part by a desire to minimize the production of radioactively contaminated waste. The current use of ceramics as containment materials for Pu processing are not ideal due to the short service life of the hardware, placing an additional burden on the contaminated waste stream. Carburized niobium has be… more
Date: December 1, 1998
Creator: Johnson, M.J.; Soderquist, S.D. & Axler, K.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Electron microscopy of some exotic materials

Description: Just about every material has been looked at under the microscope, either out of pure inquisitiveness or the need to relate the microstructure to its properties. Some of these materials are mundane, like steels or glass or polyethylene; others are so-called advanced, such as intermetallics, silicon nitride or zirconia; yet others might be called exotic whether they be martian rocks, high temperature superconductors, fullerenes, diamonds, or the latest thin film device. Many exotic materials are… more
Date: September 1, 1998
Creator: Mitchell, T.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Development of niobium spoke cavities for a superconducting light-ion linac

Description: This paper reports the development of 350 MHz niobium superconducting cavities for the velocity range 0.2 &lt; v/c &lt; 0.6. Such cavities could be used to form a linac of exceptional flexibility, capable of efficiently accelerating beams of either protons, deuterons, or any of a wide range of ions, at intensities sufficient for a production beam for a radioactive facility. Results of numerical modeling for several resonator geometries are presented. The design and construction status of protot… more
Date: August 1, 1998
Creator: Shepard, K.W.; Kedzie, M.; Delayen, J.R. & Piller, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Electromechanical properties of superconductors for DOE/OFE applications. Final report

Description: In many superconductor applications, especially large magnets, the superconductor is required to perform while under the influence of strong mechanical forces. These forces are commonly due to residual fabrication stress, differential thermal contraction of dissimilar materials, and electromagnetic forces generated within an energized magnet coil. Thorough knowledge of a superconductor`s electrical performance under the influence of these forces (electromechanical properties) is required for su… more
Date: September 1, 1998
Creator: Ekin, J. W. & Bray, S. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Z-contrast imaging of ordered structures in Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} and Ba(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}

Description: Lead-based cubic perovskites such as Pb(B{sub 1/3}{sup 2+}B{sub 2/3}{sup 5+})O{sub 3} (B{sup 2+} = Mg, Co, Ni, Zn; B{sup 5+} = Nb, Ta) are relaxor ferroelectrics. Localized order and disorder often occur in materials of this type. In the Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} (PMN) family, previous studies have proposed two models, space-charge and charge-balance models. In the first model, the ordered regions carry a net negative charge [Pb(Mg{sub 1/2}Nb{sub 1/2})O{sub 3}], while in the second mod… more
Date: February 1, 1998
Creator: Yan, Y.; Pennycook, S.J.; Xu, Z. & Viehland, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Surface structure and analysis with scanning probe microscopy and electron tunneling spectroscopy. Final report

Description: This report summarizes the results accomplished during the funding period of this grant (June 1, 1995 to May 31, 1998). The projects are (1) room-temperature atomic force microscopy (AFM) studies of NbSe{sub 3} doped with various elements and (2) low-temperature scanning tunneling microscopy (STM) studies of NbSe{sub 3}. In addition, AFM was used to study the surface morphology and defects of GaAs films grown on Ge and Ge/Si substracts.
Date: May 1, 1998
Creator: Hsu, Julia
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Application of RF Superconductivity to High Current Linac

Description: In 1997, the authors initiated a development program in Los Alamos for high-current superconducting proton-linac technology to build prototypes components of this linac to demonstrate the feasibility. The authors are building 700-MHz niobium cavities with elliptical shapes, as well as power couplers to transfer high RF power to these cavities. The cavities and power couplers will be integrated in cryostats as linac cryomodules. In this paper, they describe the linac design and the status of the… more
Date: September 13, 1998
Creator: K.C.D., Chan
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High gradient superconducting niobium cavities: A review of the present status

Description: Superconducting niobium cavities used in particle accelerators are limited in their rf performance by two phenomena: quench field levels below the theoretical limit of the material caused by defects, and field emission loading resulting from artificial contamination of the superconducting surfaces during surface treatment and assembly procedures. In recent years, the community involved in SRF technology developments has successfully improved cavity performances by applying advanced surface trea… more
Date: September 1, 1998
Creator: Kneisel, Peter
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High Temperature Materials Technology Research for Advanced Thermionic Systems. Final Report

Description: Tungsten and tungsten alloys are candidate materials for the thermionic emitter in the space nuclear power convertor. In this work, the creep behavior of HfC strengthened tungsten alloys was studied. An ultrahigh vacuum, high precision creep test system was constructed for this purpose so that the samples could be heated up to 3,000 K for heat treatment and creep strain could be measured from the creep sample inside the UHV chamber. To explain the creep behavior observed in this dispersion stre… more
Date: September 1, 1998
Creator: Zee, R. H. & Rose, M. F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Defects and site occupancies in Nb-Cr-Ti C15 Laves phase alloys

Description: A multiply-faulted dipole in the C15 Laves phase of composition Nb{sub 15}Cr{sub 68}Ti{sub 17} has been characterized. The dislocations all lie along [011] and show no residual contrast when imaged edge-on at B = [0{bar 1}{bar 1}] indicating that they are edge in character. Given this, the Burgers vectors for the Shockley partials are {+-} 1/6[2{bar 1}1] and those of the stair-rods are {+-} 1/6[0{bar 1}1]. This is consistent with a g {center_dot} b analysis which was performed. The stacking fau… more
Date: September 1, 1998
Creator: Kotula, P. G.; Carter, C. B.; Chen, K. C.; Thoma, D. J.; Chu, F. & Mitchell, T. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Time-dependent crack growth behavior of a nitrogen strengthened Ni-Fe-Cr-Nb-N alloy 120

Description: Creep and creep crack growth behavior of alloy 120 (HR120{trademark}) were studied through the time-dependent fracture mechanics characterization at 871 C (1,600 F). The material was tested under tensile, creep and creep crack propagation conditions to develop an understanding of time-dependent behavior under variable stresses at elevated temperature. The resulting properties were also compared with those of alloy 333 (RA333{trademark}) and alloy (HR160(TM)) previously obtained using the same t… more
Date: March 1998
Creator: Ren, W. & Swindeman, R. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Microstructures and Mechanical Properties of Two-Phase Alloys Based on NbCr(2)

Description: A two-phase, Nb-Cr-Ti alloy (bee+ C15 Laves phase) has been developed using several alloy design methodologies. In effort to understand processing-microstructure-property relationships, diffment processing routes were employed. The resulting microstructure and mechanical properties are discussed and compared. Plasma arc-melted samples served to establish baseline, . . . as-cast properties. In addition, a novel processing technique, involving decomposition of a supersaturated and metastable prec… more
Date: December 7, 1998
Creator: Cady, C. M.; Chen, K. C.; Kotula, P. G.; Mauro, M. E. & Thoma, D. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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