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Adjustable Permanent Quadrupoles Using Rotating Magnet Material Rods for the Next Linear Collider (open access)

Adjustable Permanent Quadrupoles Using Rotating Magnet Material Rods for the Next Linear Collider

The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 132 Tesla, with a maximum gradient of 135 Tesla per meter, an adjustment range of +0-20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micrometer during the 20% adjustment. In an effort to reduce estimated costs and increase reliability, several designs using hybrid permanent magnets have been developed. All magnets have iron poles and use either Samarium Cobalt or Neodymium Iron to provide the magnetic fields. Two prototypes use rotating rods containing permanent magnetic material to vary the gradient. Gradient changes of 20% and center shifts of less than 20 microns have been measured. These data are compared to an equivalent electromagnet prototype.
Date: September 24, 2001
Creator: al., James T Volk et
System: The UNT Digital Library
The AMPX-2000 Operating System for Producing Continuous Energy and Multi-Group Cross Sections from Basic Data Libraries Using the ENDF/B-6 Formats (open access)

The AMPX-2000 Operating System for Producing Continuous Energy and Multi-Group Cross Sections from Basic Data Libraries Using the ENDF/B-6 Formats

AMPX-2000 is a modular system of FORTRAN computer programs that relate to nuclear analysis with a primary emphasis on tasks associated with the production and use of multigroup and continuous energy cross-sections. AMPX-2000 accepts basic cross-section data from ENDF/B libraries. As opposed to previous versions of AMPX, the current version processes the latest ENDF/B version VI formats. AMPX-2000 can be used to generate a variety of multigroup libraries that can be used with modern transport codes to perform nuclear analyses. Continuous energy or ''point'' cross-section libraries can be produced for use in Monte Carlo codes and other applications. In addition, AMPX has an internal multigroup format that can be read by various AMPX modules as well as codes outside the system.
Date: August 24, 2001
Creator: Greene, N. M.
System: The UNT Digital Library
Applications of Crystal Plasticity in Multiscale Modeling (open access)

Applications of Crystal Plasticity in Multiscale Modeling

Multiscale modeling with crystal plasticity constitutive relations is used to determine the average response of a polycrystal. The measured crystallographic texture of a copper shaped charge liner is used in a crystal plasticity model to construct a yield surface that exhibits normal-shear coupling. Simulations with this yield surface model demonstrate the spinning behavior observed in the spin formed copper shaped charges.
Date: September 24, 2001
Creator: Becker, R.; Busche, M.; Schwartz, A. J. & Kumar, M.
System: The UNT Digital Library
Are the J/psi and chi_c A dependencies the same? (open access)

Are the J/psi and chi_c A dependencies the same?

It has been empirically observed that the dependence of J/{psi} and {psi}{prime} production on nuclear mass number A is very similar. This has been postulated to be due to the predominance of color octet pre-resonant states in charmonium production and absorption. Two new experiments, NA60 at CERN and HERA-B at DESY, will measure the {chi}{sub c} A dependence for the first time. These measurements should shed new light on the charmonium production and absorption mechanisms.
Date: September 24, 2001
Creator: Vogt, R.
System: The UNT Digital Library
Average Total Neutron Cross Section OF 233U, 235U AND 239Pu from ORELA Transmission Measurements and Statistical Analysis of the Data (open access)

Average Total Neutron Cross Section OF 233U, 235U AND 239Pu from ORELA Transmission Measurements and Statistical Analysis of the Data

The average total neutron cross sections of {sup 233}U, {sup 235}U, and {sup 239}Pu were obtained from transmission measurements in the unresolved resonance region up to several hundred keV neutron energy. The method used for the calculation of the self-shielding effect is described. A statistical model analysis of the results was performed and the s-, p- and d-wave neutron strength functions were obtained.
Date: August 24, 2001
Creator: Derrien, H.
System: The UNT Digital Library
Beam loading compensation requirement for multibatch coalescing in Fermilab Main Injector (open access)

Beam loading compensation requirement for multibatch coalescing in Fermilab Main Injector

Fermilab collider Run IIa requires 36 proton bunches with intensities 270E9ppb and 36 antiproton bunches with intensities 40-70E9ppb[1]. Currently the proton bunches are produced by coalescing 5-7 53MHz bunches into one 53MHz bunch and repeating this process a total of 36 times. It is necessary to coalesce each group of 5-7 bunches (called a ''batch'') on independent cycles mainly because of beam loading. The beam loading requirements that would allow us to coalesce 4 proton batches at a time are presented.
Date: July 24, 2001
Creator: al., J. Dey et
System: The UNT Digital Library
Calculation of Fragmentation Functions in Two-Hadron Semi-Inclusive Processes. (open access)

Calculation of Fragmentation Functions in Two-Hadron Semi-Inclusive Processes.

We investigate the properties of interference fragmentation functions arising from the emission of two leading hadrons inside the same jet for inclusive lepton-nucleon deep inelastic scattering. Using an extended spectator model for the mechanism of the hadronization, we give a complete calculation and numerical estimates for the examples of a proton-pion pair produced with invariant mass on the Roper resonance, and of two pions produced with invariant mass close to the {rho} mass. We discuss azimuthal angular dependence of the leading order cross section to point up favourable conditions for extracting transversity from experimental data.
Date: April 24, 2001
Creator: Bianconi, A.; Boffi, S.; Boer, D.; Jakob, R. & Radici, M.
System: The UNT Digital Library
A Comparative experimental study of media access protocols for wireless radio networks (open access)

A Comparative experimental study of media access protocols for wireless radio networks

We conduct a comparative experimental analysis of three well known media access protocols: 802.11, CSMA, and MACA for wireless radio networks. Both fixed and ad-hoc networks are considered. The experimental analysis was carried out using GloMoSim: a tool for simulating wireless networks. The main focus of experiments was to study how (i) the size of the network, (ii) number of open connections, (iii) the spatial location of individual connections, (iv) speed with which individual nodes move and (v) protocols higher up in the protocol stack (e,g. routing layer) affect the performance of the media access sublayer protocols. The performance of the protocols was measured w.r.t. three important parameters: (1) number of received packets, (2) average latency of each packet, and (3) throughput. The following general qualitative conclusions were obtained; some of the conclusions reinforce the earlier claims by other researchers. (1) Although 802.11 performs better than the other two protocols with respect to fairness of transmission, packets dropped, and latency, its performance is found to (i) show a lot of variance with changing input parameters and (ii) the overall performance still leaves a lot of room for improvement. (2) CSMA does not perform too well under the fairness criteria, however, …
Date: May 24, 2001
Creator: Barrett, C. L. (Christopher L.); Drozda, M. (Martin) & Marathe, M. V. (Madhav V.)
System: The UNT Digital Library
Comparative Study of Surface-lattice-site Resolved Neutralization of Slow Multicharged Ions during Large-angle Quasi-binary Collisions with Au(110): Simulation and Experiment (open access)

Comparative Study of Surface-lattice-site Resolved Neutralization of Slow Multicharged Ions during Large-angle Quasi-binary Collisions with Au(110): Simulation and Experiment

In this article we extend our earlier studies of the azimuthal dependences of low energy projectiles scattered in large angle quasi-binary collisions from Au(110). Measurements are presented for 20 keV Ar{sup 9+} at normal incidence, which are compared with our earlier measurements for this ion at 5 keV and 10{sup 0} incidence angle. A deconvolution procedure based on MARLOWE simulation results carried out at both energies provides information about the energy dependence of projectile neutralization during interactions just with the atoms along the top ridge of the reconstructed Au(110) surface corrugation, in comparison to, e.g., interactions with atoms lying on the sidewalls. To test the sensitivity of the agreement between the MARLOWE results and the experimental measurements, we show simulation results obtained for a non-reconstructed Au(110) surface with 20 keV Ar projectiles, and for different scattering potentials that are intended to simulate the effects on scattering trajectory of a projectile inner shell vacancy surviving the binary collision, In addition, simulation results are shown for a number of different total scattering angles, to illustrate their utility in finding optimum values for this parameter prior to the actual measurements.
Date: August 24, 2001
Creator: Meyer, F.W.
System: The UNT Digital Library
COMPLETION OF SUPERCONDUCTING MAGNET PRODUCTION AT BNL FOR THE HERA LUMINOSITY UPGRADE (open access)

COMPLETION OF SUPERCONDUCTING MAGNET PRODUCTION AT BNL FOR THE HERA LUMINOSITY UPGRADE

Brookhaven National Laboratory (BNL) has completed production of the superconducting multi-function magnets that are now installed as part of the HERA luminosity upgrade at DESY. The magnets, cryostats, and lead assemblies were designed and built at BNL. To fit inside the existing detectors, the coils plus cryostat structure had to meet a challenging radial budget (e.g., 39 mm horizontally). Two types of magnets were needed and three of each type were built. Each magnet contained normal and skew quadrupole, normal and skew dipole, and sextupole coils. The magnets operate in the {approx}1.5 T solenoid field of a detector. The quadrupole coils produce gradients up to 13 T/m. The dipole coils generate fields up to 0.3 T. Coils were wound under computer control using either seven-strand round cable or a single strand. To simultaneously avoid excessive synchrotron radiation background scattered from the beam pipe and yet have a small cryostat, one type of magnet used a tapered coil structure. The cryogenic system incorporates cooling with both 40 K helium and supercritical helium. All of the coils were tested in liquid helium in a vertical dewar. Quench test results have been excellent. The field quality of the magnets has met the stringent …
Date: September 24, 2001
Creator: WANDERER,P. ANERELLA,M. ESCALLIER,J. GHOSH,A. JAIN,A. MARONE,A. MURATORE,J. PARKER,A. PRODELL,A. THOMPSON,P. WU,K. C.
System: The UNT Digital Library
Conceptual Design of Pion Capture Magnets of Up to 15 Cm Bore and 20 T Peak Field. (open access)

Conceptual Design of Pion Capture Magnets of Up to 15 Cm Bore and 20 T Peak Field.

For the Neutrino Factory and Muon Collider Collaboration, BNL has considered solenoidal magnet systems of several types to capture pions generated by bombarding a mercury jet with multi-GeV protons. The magnet systems generate up to 20 T, uniform to 5% throughout a cylindrical volume 0.15 m in diameter and 0.6 m long. Axially downstream the field ramps gradually downward by a factor of sixteen, while the bore increases fourfold. The steady-state system needed for an accelerator has many superconducting coils and a radiation-resistant insert of mineral-insulated hollow conductor. Less costly, pulsed systems suffice to study pion capture and the effect of a magnetic field on a jet hit by a proton beam. BNL has explored three types of magnets, each with its principal coils precooled by liquid nitrogen. One type employs two sets of coils energized sequentially. Charged in 23 s by a power supply of 5 MVA, the 16ton outer set generates 10 T and stores 28 MJ, from which, in 1/3 s, to charge a half-ton inner coil that adds 12 1/2 T to the 7 1/2 T remaining from the outer set. An alternative design uses 25 MVA to energize, in 1.4 s, a single 3-ton set …
Date: September 24, 2001
Creator: Weggel, R. J.
System: The UNT Digital Library
Decommissioning the Brookhaven National Laboratory Building 830 Gamma Irradiation Facility (open access)

Decommissioning the Brookhaven National Laboratory Building 830 Gamma Irradiation Facility

The Building 830 Gamma Irradiation Facility (GIF) at Brookhaven National Laboratory (BNL) was decommissioned because its design was not in compliance with current hazardous tank standards and because its cobalt-60 sources were approaching the end of their useful life. The facility contained 354 stainless steel encapsulated cobalt-60 sources in a pool, which provided shielding. Total cobalt-60 inventory amounted to 24,000 Curies (when the sources were shipped for disposal). The decommissioning project included packaging, transport and disposal of the sources and dismantling and disposing of all other equipment associated with the facility. Worker exposure was a major concern in planning for the packaging and disposal of the sources. These activities were planned carefully according to ALARA (As Low As Reasonably Achievable) principles. As a result, the actual doses experienced during the work were lower than anticipated. Because the sources were sealed, most of the remaining equipment was not contaminated; therefore disposal was straightforward, as scrap metal and construction debris. However, disposal of the pool water involved addressing environmental concerns, since the planned method was to discharge the slightly contaminated water to the BNL sewage treatment plant.
Date: February 24, 2001
Creator: Bowerman, B.; Sullivan, P. T. & Moore, D.
System: The UNT Digital Library
DISTRIBUTED CONTAINER FAILURE MODELS FOR THE DUST-MS COMPUTER CODE. (open access)

DISTRIBUTED CONTAINER FAILURE MODELS FOR THE DUST-MS COMPUTER CODE.

Improvements to the DUST-MS computer code have been made that permit simulation of distributed container failure rates. The new models permit instant failure of all containers within a computational volume, uniform failure of these containers over time, or a normal distribution in container failures. Incorporation of a distributed failure model requires wasteform releases to be calculated using a convolution integral. In addition, the models permit a unique time of emplacement for each modeled container and allow a fraction of the containers to fail at emplacement. Implementation of these models, verification testing, and an example problem comparing releases from a wasteform with a two-species decay chain as a function of failure distribution are presented in the paper.
Date: February 24, 2001
Creator: Sullivan,Terry & de Lemos, Francisco
System: The UNT Digital Library
Effect of partially reacting Nb{sub 3}Sn before magnet winding on the strand critical current (open access)

Effect of partially reacting Nb{sub 3}Sn before magnet winding on the strand critical current

Nb{sub 3}Sn is currently the material most commonly foreseen for the development of high field superconducting magnets. This is done by either the wind and react technique, usually used for compact magnets like accelerator magnets, or the react and wind technique, more common on large scale magnets. In both cases, a thorough understanding of the Cu-Sn system diffusion and phase formation processes is necessary to optimize the Nb{sub 3}Sn reaction cycle. Attention has to be paid to both the superconducting performance and the prevention of thermally induced damage of the final produced conductor. The formation of the eta and epsilon phases of the Cu-Sn phase diagram were investigated as a function of time and temperature. Wherever possible, the activation energies and diffusion coefficients were calculated. The feasibility of winding partly reacted cables to reduce the manufacturing time was also explored. Nb{sub 3}Sn strands have been partially reacted to convert the Sn to the eta and epsilon phases of the Cu-Sn phase diagram, then plastically strained to figure out a cabling and/or a winding degradation. After completion of the reaction cycle, the critical current was measured and compared with that obtained with an uninterrupted cycle.
Date: August 24, 2001
Creator: al., J.M. Rey et
System: The UNT Digital Library
Enhanced Detection of Proteins in Microchip Separations by On-Chip Preconcentration (open access)

Enhanced Detection of Proteins in Microchip Separations by On-Chip Preconcentration

Microfluidic chips incorporating a semiporous glass filter were used to electrokinetically concentrate proteins on-chip prior to injection and electrophoretic analysis. Signal enhancements of >100-fold could be achieved for the microchip analysis of both native and SDS-denatured proteins using this technique.
Date: May 24, 2001
Creator: Foote, R. S.
System: The UNT Digital Library
Evidence of Collisional Coherences in the Transport of Hydrogenic Krypton through Amorphous Carbon Foils (open access)

Evidence of Collisional Coherences in the Transport of Hydrogenic Krypton through Amorphous Carbon Foils

We study theoretically and experimentally the population dynamics of the internal state of 60MeV/u Kr35+ ions traversing amorphous carbon foils. A quantum transport theory is developed that incorporates the state mixing induced by the wake field of the ion as well as all the coherences generated by the collisional and radiative redistribution of states. We show that the internal state of the ion is sensitive to collisional coherences and the wake field. The results of the full simulations are found to be in good agreement with experimental data.
Date: August 24, 2001
Creator: Minami, T.
System: The UNT Digital Library
Fermilab recycler diagnostics (open access)

Fermilab recycler diagnostics

The Fermilab Recycler Ring is a permanent magnet storage ring for the storage and cooling of antiprotons. The following note describes the diagnostic tools currently available for commissioning, as well as the improvements and upgrades planned for the near future.
Date: July 24, 2001
Creator: Hu, Martin
System: The UNT Digital Library
The Fermilab recycler ring (open access)

The Fermilab recycler ring

The Fermilab Recycler is a permanent magnet storage ring for the accumulation of antiprotons from the Antiproton Source, and the recovery and cooling of the antiprotons remaining at the end of a Tevatron store. It is an integral part of the Fermilab III luminosity upgrade. The following paper describes the design features, operational and commissioning status of the Recycler Ring.
Date: July 24, 2001
Creator: Hu, Martin
System: The UNT Digital Library
Incorporating the productivity benefits into the assessment of cost effective energy savings potential using conservation supply curves (open access)

Incorporating the productivity benefits into the assessment of cost effective energy savings potential using conservation supply curves

We review the relationship between energy efficiency improvement measures and productivity in industry. We propose a method to include productivity benefits in the economic assessment of the potential for energy efficiency improvement. The paper explores the implications of how this change in perspective might affect the evaluation of energy-efficient technologies for a study of the iron and steel industry in the U.S. It is found that including productivity benefits explicitly in the modeling parameters would double the cost-effective potential for energy efficiency improvement, compared to an analysis excluding those benefits. We provide suggestions for future research for this important area.
Date: July 24, 2001
Creator: Laitner, John A.; Ruth, Michael & Worrell, Ernst
System: The UNT Digital Library
Inelastic Neutron Scattering Measurements of Phonon Dispersion Relations in Andalusite and Sillimanite, Al{sub 2}SiO{sub 5} (open access)

Inelastic Neutron Scattering Measurements of Phonon Dispersion Relations in Andalusite and Sillimanite, Al{sub 2}SiO{sub 5}

This paper reports inelastic neutron scattering (INS) measurements of the phonon dispersion relations of the aluminum silicate minerals andalusite and sillimanite, Al{sub 2}SiO{sub 5}. The single crystal INS measurements were undertaken using the Triple-axis-spectrometer at the Dhruva reactor, Trombay for andalusite and at the Oak Ridge National Laboratory, USA for sillimanite. The phonon dispersion relations (upto 50 mev) along various high symmetry directions have been measured and have been analyzed on the basis of lattice dynamics shell model calculations. The calculated structure factors based on the model calculations were used as guides for planning these single crystal measurements and were used to identify regions in reciprocal space with large cross-sections. The calculated structure factors have been very useful in the planning, execution and analysis of the experimental data. The calculated phonon dispersion relations are found to be in good agreement with the measured data .
Date: April 24, 2001
Creator: Goel, P.
System: The UNT Digital Library
Integrated simulation environment for lighting design (open access)

Integrated simulation environment for lighting design

Lighting design involves the consideration of multiple performance criteria, from the earliest stages of conceptual design, through various stages of controls and operation in a project's life cycle. These criteria include: (1) the quantitative analysis of illuminance and luminance distribution due to daylighting and electric lighting; (2) qualitative analysis of the lighting design with photometrically accurate renderings of the designed environment; (3) analysis of energy implications of daylighting and electric lighting design and operation;, and (4) analysis of control strategies and sensor placement for maximizing energy savings from lighting control while providing visual comfort. In this paper we describe the development of an integrated decision-making environment that brings together several different tools, and provides the data management and process control required for a multi-criterion support of the design and operation of daylighting and electric lighting systems. The result is a powerful design and decision-making environment to meet the diverse and evolving needs of lighting designers and operators.
Date: May 24, 2001
Creator: Pal, Vineeta & Papamichael, Konstantinos
System: The UNT Digital Library
Intense Electron Beam Disruption Due to Ion Release From Surface (open access)

Intense Electron Beam Disruption Due to Ion Release From Surface

None
Date: July 24, 2001
Creator: Vermare, C.; Davis, H. A. & Al, Et
System: The UNT Digital Library
INTERACTION REGION MAGNETS FOR VLHC. (open access)

INTERACTION REGION MAGNETS FOR VLHC.

The interaction region (IR) magnets for the proposed very large hadron collider (VLHC) require high gradient quadrupoles and high field dipoles for high luminosity performance. Moreover, the IR magnets for high energy colliders and storage rings must operate in an environment where the amount of energy deposited on superconducting coils is rather large. In the case of doublet IR optics with flat beams, the design of the first 2-in-1 quadrupole defines the geometry and pole tip field in this and other IR magnets. This paper will present a novel design of this magnet that allows a very small separation between the two apertures. A brief discussion of the conceptual magnetic design of this and other magnets for interaction regions is given. The influence of critical current density in superconductor (a higher value of which is most beneficial to high performance IR magnet design) is also discussed. Since High Temperature Superconductors (HTS) retain most of their critical current density at high fields and at elevated temperatures, they offer an attractive possibility for the IR magnet designs of future colliders or upgrades of present colliders.
Date: September 24, 2001
Creator: Gupta, R. & Harrison, M.
System: The UNT Digital Library
Kaon Condensation in Neutron Stars. (open access)

Kaon Condensation in Neutron Stars.

We discuss the kaon-nucleon interaction and its consequences for the change of the properties of the kaon in the medium. The onset of kaon condensation in neutron stars under various scenarios as well its effects for neutron star properties are reviewed.
Date: April 24, 2001
Creator: Ramos, A.; Schaffner-Bielich, J. & Wambach, J.
System: The UNT Digital Library