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High field solenoids for muon cooling (open access)

High field solenoids for muon cooling

The proposed cooling system for the muon collider will consist of a 200 meter long line of alternating field straight solenoids interspersed with bent solenoids. The muons are cooled in all directions using a 400 mm long section liquid hydrogen at high field. The muons are accelerated in the forward direction by about 900 mm long, 805 MHz RF cavities in a gradient field that goes from 6 T to -6 T in about 300 mm. The high field section in the channel starts out at an induction of about 2 T in the hydrogen. As the muons proceed down the cooling channel, the induction in the liquid hydrogen section increases to inductions as high as 30 T. The diameter of the liquid hydrogen section starts at 750 mm when the induction is 2 T. As the induction in the cooling section goes up, the diameter of the liquid hydrogen section decreases. When the high field induction is 30 T, the diameter of the liquid hydrogen section is about 80 mm. When the high field solenoid induction is below 8.5 T or 9T, niobium titanium coils are proposed for generating .the magnetic field. Above 8.5 T or 9 T to …
Date: September 8, 1999
Creator: Green, M. A.; Eyssa, Y.; Kenny, S.; Miller, J. R. & Prestemon, S.
System: The UNT Digital Library
RHIC IR Quadrupoles and Field Quality State of the Art in Super Conducting Accelerator Magnets (open access)

RHIC IR Quadrupoles and Field Quality State of the Art in Super Conducting Accelerator Magnets

The interaction region (IR) quadrupoles [1] for the Relativistic Heavy Ion Collider (RHIC)[2]are the best field quality superconducting magnets ever built for any major accelerator. This field quality is primarily achieved with the help of eight tuning shims [3] that remove the residual errors from a magnet after it is built and tested. These shims overcome the limitations from the typical tolerances in parts and manufacturing. This paper describes the tuning shims and discusses the evolution of a flexible approach that allowed changes in the design parameters and facilitated using parts with significant dimensional variations while controlling cost and maintaining schedule and field quality. The RHIC magnet program also discovered that quench and thermal cycles cause small changes [4]in magnet geometry. The ultimate field quality performance is now understood to be determined by these changes rather than the manufacturing tolerances or the measurement errors.
Date: March 8, 1999
Creator: Gupta, R.; Anerella, M.; Cozzolino, J.; Ghosh, A.; Jain, A.; Kahn, S. et al.
System: The UNT Digital Library
Installation of line replaceable units into the National Ignition Facility (open access)

Installation of line replaceable units into the National Ignition Facility

In the National Ignition Facility (NIF), currently under design and construction at Lawrence Livermore National Laboratory (LLNL), 192 high-power laser beamlines incorporating over 8,000 large optics, are focused onto a target smaller than a dime. The actual laser path will be contained within the Laser Target Area Building (LTAB), but the smaller adjacent building, the Optics Assembly Building, is where the optic modules are assembled and aligned. After the optics are finished in the OAB they must be transported and installed into the LTAB. While this is done strict cleanliness and handling conditions must be maintained. To maximize the efficiency of this process the optics are assembled into Line Replaceable Units (LRUs), which typically consist of a mechanical housing, laser optics, utilities, actuators and kinematic mounts. In this paper the Optical Transport and Material Handling designs that will be used to deliver the LRUs into the NIF laser bays are presented. Five types of delivery systems have been developed to deliver the LRUs to their locations in the LTAB. They are top loading, bottom loading, side loading, switchyard loading and target area loading. The first three operate in the laser bay of the LTAB and are transported between the OAB …
Date: March 8, 1999
Creator: Bahowick, S; Mcmahon, D; Rowe, A; Tiszauer, D & Yakuma, S
System: The UNT Digital Library
B Decays as a probe of spontaneous cp-violation in SUSY models (open access)

B Decays as a probe of spontaneous cp-violation in SUSY models

We consider phenomenological implications of susy models with spontaneously broken CP-symmetry. In particular, we analyze CP-asymmetries in B decays and find that the predictions of these models are vastly different from those of the SM. These features are common to NMSSM-like models with an arbitrary number of sterile superfields and the MSSM with broken R-parity.
Date: July 8, 1999
Creator: Lebedev, Oleg
System: The UNT Digital Library
Gas Phase Chemical Detection with an Integrated Chemical Analysis System (open access)

Gas Phase Chemical Detection with an Integrated Chemical Analysis System

Microfabrication technology has been applied to the development of a miniature, multi-channel gas phase chemical laboratory that provides fast response, small size, and enhanced versatility and chemical discrimination. Each analysis channel includes a sample concentrator followed by a gas chromatographic separator and a chemically selective surface acoustic wave detector array to achieve high sensitivity and selectivity. The performance of the components, individually and collectively, is described. The design and performance of novel micromachined acoustic wave devices, with the potential for improved chemical sensitivity, are also described.
Date: July 8, 1999
Creator: Baca, Albert G.; Casalnuovo, Stephen A.; Frye-Mason, Gregory C.; Heller, Edwin J.; Hietala, Susan L.; Hietala, Vincent M. et al.
System: The UNT Digital Library
RF and mm-Wave Photonics at Sandia National Laboratories (open access)

RF and mm-Wave Photonics at Sandia National Laboratories

RF and mm-wave photonic devices and circuits have been developed at Sandia National Laboratories for applications ranging from RF optical data links to optical generation of mm-wave frequencies. This talk will explore recent high-speed photonics technology developments at Sandia including: (1) A monolithic optical integrated circuit for all-optical generation of mm-waves. Using integrated mode-locked diode lasers, amplifiers, and detectors, frequencies between 30 GHz and 90 GHz are generated by a single monolithic (Al,Ga)As optical circuit less than 2mm in its largest dimension. (2) Development of polarization-maintaining, low-insertion-loss, low v-pi, Mach-Zehnder interferometer (MZI) modulators with DC-to-potentially-K-band modulation bandwidth. New low-loss polarization-maintaining waveguide designs using binary alloys have been shown to reduce polarization crosstalk in undoped (Al,Ga)As waveguides, yielding high extinction ratio (>40dB) and low on-chip loss (<6dB) in Mach-Zehnder interferometers. RF drive voltage is reduced through use of 45rnrn-active length devices with modulator sensitivity, v-pi, less than 3V.
Date: July 8, 1999
Creator: Vawter, G. A. & Sullivan, C.
System: The UNT Digital Library
High-resolution wavefront control of high-power laser systems (open access)

High-resolution wavefront control of high-power laser systems

Nearly every new large-scale laser system application at LLNL has requirements for beam control which exceed the current level of available technology. For applications such as inertial confinement fusion, laser isotope separation, laser machining, and laser the ability to transport significant power to a target while maintaining good beam quality is critical. There are many ways that laser wavefront quality can be degraded. Thermal effects due to the interaction of high-power laser or pump light with the internal optical components or with the ambient gas are common causes of wavefront degradation. For many years, adaptive optics based on thing deformable glass mirrors with piezoelectric or electrostrictive actuators have be used to remove the low-order wavefront errors from high-power laser systems. These adaptive optics systems have successfully improved laser beam quality, but have also generally revealed additional high-spatial-frequency errors, both because the low-order errors have been reduced and because deformable mirrors have often introduced some high-spatial-frequency components due to manufacturing errors. Many current and emerging laser applications fall into the high-resolution category where there is an increased need for the correction of high spatial frequency aberrations which requires correctors with thousands of degrees of freedom. The largest Deformable Mirrors currently available …
Date: July 8, 1999
Creator: Brase, J.; Brown, C.; Carrano, C.; Kartz, M.; Olivier, S.; Pennington, D. et al.
System: The UNT Digital Library
Texture Development During Equal Channel Angular Forging of BCC Metals (open access)

Texture Development During Equal Channel Angular Forging of BCC Metals

Equal channel angular forging (ECAF) has been proposed as a severe plastic deformation technique for processing metals, alloys, and composites [e.g. Segal, 1995] (Fig. 1). The technique offers two capabilities of practical interest: a high degree of strain can be introduced with no change in the cross-sectional dimensions of the work-piece, hence, even greater strains can be introduced by re-inserting the work-piece for further deformation during subsequent passes through the ECAF die. Additionally, the deformation is accomplished by simple shear (like torsion of a short tube) on a plane whose orientation, with respect to prior deformations, can be controlled by varying the processing route. There is a nomenclature that has developed in the literature for the typical processing routes: A: no rotations; B{sub A}: 90 degrees CW (clockwise), 90 degrees CCW (counterclockwise), 9O degrees CW, 90 degrees CCW...; Bc: 90 degrees CW, 90 degrees CW, 90 degrees CW...; and C: 180 degrees, 18 0 degrees.... The impact of processing route on the subsequent microstructure [Ferasse, Segal, Hartwig and Goforth, 1997; Iwahashi, Horita, Nemoto and Langdon, 1996] and texture [Gibbs, Hartwig, Cornwell, Goforth and Payzant, 1998] has been the subject of numerous experimental studies.
Date: August 8, 1999
Creator: Agnew, S. R.
System: The UNT Digital Library
Unattended Monitoring System Design Methodology (open access)

Unattended Monitoring System Design Methodology

A methodology for designing Unattended Monitoring Systems starting at a systems level has been developed at Sandia National Laboratories. This proven methodology provides a template that describes the process for selecting and applying appropriate technologies to meet unattended system requirements, as well as providing a framework for development of both training courses and workshops associated with unattended monitoring. The design and implementation of unattended monitoring systems is generally intended to respond to some form of policy based requirements resulting from international agreements or domestic regulations. Once the monitoring requirements are established, a review of the associated process and its related facilities enables identification of strategic monitoring locations and development of a conceptual system design. The detailed design effort results in the definition of detection components as well as the supporting communications network and data management scheme. The data analyses then enables a coherent display of the knowledge generated during the monitoring effort. The resultant knowledge is then compared to the original system objectives to ensure that the design adequately addresses the fundamental principles stated in the policy agreements. Implementation of this design methodology will ensure that comprehensive unattended monitoring system designs provide appropriate answers to those critical questions imposed by …
Date: July 8, 1999
Creator: Drayer, D. D.; DeLand, S. M.; Harmon, C. D.; Matter, J. C.; Martinez, R. L. & Smith, J. D.
System: The UNT Digital Library
Radial Excitations (open access)

Radial Excitations

In this contribution I discuss recent experimental developments in the Spectroscopy of higher-mass mesons, especially candidate radial excitations discussed at the WHS99 meeting in Frascati.
Date: March 8, 1999
Creator: Barnes, T.
System: The UNT Digital Library
Experiences Using a Meta-Data Based Integration Infrastructure (open access)

Experiences Using a Meta-Data Based Integration Infrastructure

A data warehouse that presents data from many of the genomics community data sources in a consistent, intuitive fashion has long been a goal of bioinformatics. Unfortunately, it is one of the goals that has not yet been achieved. One of the major problems encountered by previous attempts has been the high cost of creating and maintaining a warehouse in a dynamic environment. In this abstract we have outlined a meta-data based approach to integrating data sources that begins to address this problem. We have used this infrastructure to successfully integrate new sources into an existing warehouse in substantially less time than would have traditionally been required--and the resulting mediators are more maintainable than the traditionally defined ones would have been. In the final paper, we will describe in greater detail both our architecture and our experiences using this framework. In particular, we will outline the new, XML based representation of the meta-data, describe how the mediator generator works, and highlight other potential uses for the meta-data.
Date: July 8, 1999
Creator: Critchlow, T.; Masick, R. & Slezak, T.
System: The UNT Digital Library
Optical Readout of Micro-Accelerometer Code Features (open access)

Optical Readout of Micro-Accelerometer Code Features

Micromachine accelerometers offer a way to enable critical functions only when a system encounters a particular acceleration environment. This paper describes the optical readout of a surface micromachine accelerometer containing a unique 24-bit code. The readout uses waveguide-based optics, which are implemented as a photonic integrated circuit (PIC). The PIC is flip-chip bonded over the micromachine, for a compact package. The shuttle moves 500 {micro}m during readout, and each code element is 17 {micro}m wide. The particular readout scheme makes use of backscattered radiation from etched features in the accelerometer shuttle. The features are etched to create corner reflectors that return radiation back toward the source for a one bit. For a zero bit, the shuttle is not etched, and the radiation scatters forward, away from the detector. This arrangement provides a large signal difference between a one and zero signal, since the zero signal returns virtually no signal to the detector. It is thus superior to schemes that interrogate the code vertically, which have a limited contrast between a one and a zero. Experimental results are presented for mock shuttle features etched into a silicon substrate. To simulate the shuttle moving under a fixed PIC, a commercially available waveguide …
Date: July 8, 1999
Creator: Dickey, Fred M.; Holswade, Scott C.; Polosky, Marc A.; Shagam, Richard N. & Sullivan, Charles T.
System: The UNT Digital Library
3-D Silicon Photonic Lattices- Cornerstone of an Emerging Photonics Revolution (open access)

3-D Silicon Photonic Lattices- Cornerstone of an Emerging Photonics Revolution

Three-dimensional photonic lattices are engineered materials which are the photonic analogues of semiconductors. These structures were first proposed and demonstrated in the mid-to-late 1980's. However, due to fabrication difficulties, lattices active in the infrared are only just emerging. Wide ranges of structures and fabrication approaches have been investigated. The most promising approach for many potential applications is a diamond-like structure fabricated using silicon microprocessing techniques. This approach has enabled the fabrication of 3-D silicon photonic lattices active in the infrared. The structures display band gaps centered from 12{micro} down to 1.55{micro}.
Date: July 8, 1999
Creator: Fleming, J.G. & Lin, Shawn-Yu
System: The UNT Digital Library
Application of the Two-Parameter J-A2 Description to Ductile Crack Growth (open access)

Application of the Two-Parameter J-A2 Description to Ductile Crack Growth

Typical ASTM fracture testing determines J-integral resistance (J-R) curve or fracture toughness (JIC) based on specimens with high constraint geometry such as those specified in ASTM E1737-96. A three-term asymptotic solution with two parameters J and A2 (a constraint parameter) has been developed for characterizing the constraint effect of various geometries. The present paper extends the J-A2 characterization of a stationary crack tip to the regime of stable crack growth. Similar to the concept of J-controlled crack growth, the J-A2 description can be approximately used to characterize ductile crack growth under certain amount of crack extension. The region of J-A2 controlled crack growth is much larger than that controlled by J-integral alone. From the relationships between A2 and the test data, JIC and tearing modulus (TR), the coefficients used to define a J-R curve can be determined. For non-standard specimens or actual structures, once the constraint parameter A2 is determined, the J-R curves appropriate for these geometries can then be obtained. A procedure of transferring J-R curves determined from the standard ASTM procedure to non-standard specimens or flawed structures is outlined in the paper.
Date: July 8, 1999
Creator: Lam, P.S.
System: The UNT Digital Library
The Potential for Low-Cost Concentrating Solar Power Systems (open access)

The Potential for Low-Cost Concentrating Solar Power Systems

Concern over the possibility of global climate change as a result of anthropogenic greenhouse gas buildup in the atmosphere is resulting in increased interest in renewable energy technologies. The World Bank recently sponsored a study to determine whether solar thermal power plants can achieve cost parity with conventional power plants. The paper reviews the conclusions of that study.
Date: July 8, 1999
Creator: Price, H. W. (National Renewable Energy Laboratory) & Carpenter, S. (Enermodal Engineering Limited)
System: The UNT Digital Library
Self-Adjoint Angular Flux Equation for Coupled Electron-Photon Transport (open access)

Self-Adjoint Angular Flux Equation for Coupled Electron-Photon Transport

Recently, Morel and McGhee described an alternate second-order form of the transport equation called the self adjoint angular flux (SAAF) equation that has the angular flux as its unknown. The SAAF formulation has all the advantages of the traditional even- and odd-parity self-adjoint equations, with the added advantages that it yields the full angular flux when it is numerically solved, it is significantly easier to implement reflective and reflective-like boundary conditions, and in the appropriate form it can be solved in void regions. The SAAF equation has the disadvantage that the angular domain is the full unit sphere and, like the even- and odd- parity form, S{sub n} source iteration cannot be implemented using the standard sweeping algorithm. Also, problems arise in pure scattering media. Morel and McGhee demonstrated the efficacy of the SAAF formulation for neutral particle transport. Here we apply the SAAF formulation to coupled electron-photon transport problems using multigroup cross-sections from the CEPXS code and S{sub n} discretization.
Date: July 8, 1999
Creator: Liscum-Powell, J. L.; Lorence, L. J., Jr.; Morel, J. E. & Prinja, A. K.
System: The UNT Digital Library
Refractive Index and Hygroscopic Stability of Al(x)Ga(1-x)As Native Oxides (open access)

Refractive Index and Hygroscopic Stability of Al(x)Ga(1-x)As Native Oxides

The authors present prism coupling measurements on Al{sub x}Ga{sub 1{minus}x}As native oxides showing the dependence of refractive index on composition (0.3 {le} x {le} 0.97), oxidation temperature (400 {le} T {le} 500), and carrier gas purity. Index values range from n = 1.490 (x = 0.9, 400) to 1.707 (x = 0.3, 500 C). The oxides are shown to adsorb moisture, increasing their index by up to 0.10 (7%). Native oxides of Al{sub x}Ga{sub 1{minus}x}As (x {le} 0.5) have index values up to 0.27 higher and are less hygroscopic when prepared with a small amount of O{sub 2} in the N{sub 2} + H{sub 2}O process gas. The higher index values are attributed to a greater degree of oxidation of the Ga in the film.
Date: July 8, 1999
Creator: Blum, O.; Epstein, R. J.; Hou, H.; Hall, D. C.; Kou, L.; Luo, Y. et al.
System: The UNT Digital Library
Operational Restoration of the Pen Branch Bottomland Hardwoos and Swamp Wetlands-The Research Setting (open access)

Operational Restoration of the Pen Branch Bottomland Hardwoos and Swamp Wetlands-The Research Setting

Historiexecy the SRS swamp was largely composed of bald cypress and tupelo forest with lesser amounts of hardwoods. Upstream impacts from dam construction have altered the composition of the forest through changes in the flooding regimes. Pumping of hot water in to Pen Branch resulted in destruction of several hundred acres of the native forest. Overflow of the forest redistributed sediment, eroded the channel and deposition of silt. No natural regeneration of hardwoods or cypress were observed following cessation of reactor operations. Research was conducted to test various strategies for reforesting these areas.
Date: June 8, 1999
Creator: Nelson, E. A.; Dulohery, N. C.; Kolka, R. K. & McKee, W.
System: The UNT Digital Library
Observation of Secondary Plasma Waves in Laser-Plasma Interaction Experiments (open access)

Observation of Secondary Plasma Waves in Laser-Plasma Interaction Experiments

An experiment is described where the two products of the Langmuir Decay Instability (LDI) of a primary electron plasma wave have been observed and identified without any ambiguity. Primary Langmuir waves are driven by Stimulated Raman Scattering (SRS) of an incident laser which provides well-defined electron plasma waves. Thomson scattering of a short wavelength probe beam yields measurements of the amplitude of the waves resolved in time, space, wavelength and wavevector, that allow identification of the probed waves.
Date: December 8, 1999
Creator: Depierreux, S.; Labaune, C.; Baldis, H. A.; Fuchs, J. & Michard, A.
System: The UNT Digital Library
["A friend indeed?" article, June 8, 1999] (open access)

["A friend indeed?" article, June 8, 1999]

An article, written by Chris Bull for The Advocate, about hopes for George W. Bush's future actions and policies on gay and lesbian rights. It highlights Bush's friendship with Charles C. Francis and includes the words of other activists and people interested in the topic.
Date: June 8, 1999
Creator: Bull, Chris
System: The UNT Digital Library
Progress and future plans for MPC and A at Chelyabinsk-70 (open access)

Progress and future plans for MPC and A at Chelyabinsk-70

This paper describes that portion of the Nuclear Materials Protection, Control, and Accounting (MPC and A) program that is directed specifically to the needs of the All Russian Scientific Research Institute of Technical Physics (VNIITF), also called Chelyabinsk-70. Chelyabinsk-70 is located in the Ural Mountains, approximately 2000 km east of Moscow and 100 km south of Ekaterinburg. The MPC and A work that has been completed, is underway and planned at the facility will be described. During the first two years of the VNIITF project, emphasis was on the Pulse Research Reactor Facility (PRR), which contains one metal and two liquid pulse reactors and associated nuclear material storage rooms and a control center. A commissioning of the PRR was held in May of 1998. With the completion of the MPC and A work in the PRR, new physical protection work is focusing on other areas. VNIITF-wide physical protection initiatives underway include access control and computerized badging systems, and a central MPC and A control system. Measured physical inventory taking is a high priority for the VNIITF Project Team. A VNIITF-wide computerized accounting system is also being developed for the large and diverse inventory of nuclear material subject to MPC and …
Date: July 8, 1999
Creator: Apt, K.; Blasy, J.; Bukin, D.; Cahalane, P.; Churikov, Y.; Curtis, D. et al.
System: The UNT Digital Library
Beam tests of the 12 MHz RFQ RIB injector for ATLAS. (open access)

Beam tests of the 12 MHz RFQ RIB injector for ATLAS.

In recent tests without beam, the Argonne 12 MHz split-coaxial radio-frequency quadruple (RFQ) achieved a cw intervane voltage of more than 100 kV, the design operating voltage for the device. This voltage is sufficient for the RFQ to function as the first stage of a RIB injector for the Argonne Tandem Linear Accelerator System (ATLAS). Previously reported beam dynamics calculations for the structure predict longitudinal emittance growth of only a few keV{center_dot}ns for beams of mass 132 and above with transverse emittance of 0.27 {pi} mm{center_dot}mrad (normalized). Such beam quality is not typical of RFQ devices. The work reported here is preparation for tests with beams of mass up to 132. Beam diagnostic stations are being developed to measure the energy gain and beam quality of heavy ions accelerated by the RFQ using the Dynamitron accelerator facility at the ANL Physics Division as the injector. Beam diagnostic development includes provisions for performing the measurements with both a Si charged-particle detector and an electrostatic energy spectrometer system.
Date: February 8, 1999
Creator: Kaye, R. A.
System: The UNT Digital Library
Medical applications of ultra-short pulse lasers (open access)

Medical applications of ultra-short pulse lasers

The medical applications for ultra short pulse lasers (USPLs) and their associated commercial potential are reviewed. Short pulse lasers offer the surgeon the possibility of precision cutting or disruption of tissue with virtually no thermal or mechanical damage to the surrounding areas. Therefore the USPL offers potential improvement to numerous existing medical procedures. Secondly, when USPLs are combined with advanced tissue diagnostics, there are possibilities for tissue-selective precision ablation that may allow for new surgeries that cannot at present be performed. Here we briefly review the advantages of short pulse lasers, examine the potential markets both from an investment community perspective, and from the view. of the technology provider. Finally nominal performance and cost requirements for the lasers, delivery systems and diagnostics and the present state of development will be addressed.
Date: June 8, 1999
Creator: Kim, B. M. & Marion, J. E.
System: The UNT Digital Library