Eddy Current Effect of the Bnl-Ags Vacuum Chamber on the Optics of the Bnl-Ags Synchrotron. (open access)

Eddy Current Effect of the Bnl-Ags Vacuum Chamber on the Optics of the Bnl-Ags Synchrotron.

During the acceleration cycle of the AGS synchrotron, eddy currents are generated within the walls of the vacuum chambers of the AGS main magnets. The vacuum chambers have elliptical cross section, are made of inconel material with a wall thickness of 2 mm and are placed within the gap of the combined-function main magnets of the AGS synchrotron. The generation of the eddy currents in the walls of the vacuum chambers, creates various magnetic multipoles, which affect the optics of the AGS machine. In this report these magnetic multipoles are calculated for various time interval starting at the acceleration cycle, where the magnetic field of the main magnet is {approx}0.1 T, and ending before the beam extraction process, where the magnetic field of the main magnet is almost constant at {approx}1.1 T. The calculations show that the magnetic multipoles generated by the eddy-currents affect the optics of the AGS synchrotron during the acceleration cycle and in particular at low magnetic fields of the main magnet. Their effect is too weak to affect the optics of the AGS machine during beam extraction at the nominal energies.
Date: March 29, 1999
Creator: Tsoupas, N.; Ahrens, L.; Brown, K. A.; Glenn, J. W. & Gardner, K.
System: The UNT Digital Library
Absolute dipole gamma-ray strength functions for /sup 176/Lu (open access)

Absolute dipole gamma-ray strength functions for /sup 176/Lu

We have derived absolute dipole strength-function information for /sup 176/Lu from an average resonance capture study of /sup 175/Lu with 2-keV neutrons, and from neutron capture cross-section measurements with neutrons from 30 keV to about 1 MeV. We found that we needed to increase our previous estimate of the relative M1/E1 strengths near 5 MeV by a factor of 3, and to revise downward the absolute magnitude of our E1 strength function. We accomplished the latter, while still maintaining continuity with the photonuclear data, by adjusting the one free parameter in our line shape. The present E1 and M1 strengths now seem correct both near the neutron separation energy and also around 1 MeV.
Date: August 29, 1984
Creator: Gardner, D. G.; Gardner, M. A. & Hoff, R. W.
System: The UNT Digital Library
Isomer ratio calculations using modeled discrete levels (open access)

Isomer ratio calculations using modeled discrete levels

We have calculated isomer ratios for the /sup 175/Lu(n,..gamma..), /sup 175/Lu(n,2n), /sup 237/Np(n,2n), /sup 241/Am(n,..gamma..), and /sup 243/Am(n,..gamma..) reactions using modeled level structures in the deformed, odd-odd product nuclei. We find: that the hundreds of discrete levels and their gamma-ray branching ratios provided by the modeling are necessary to achieve agreement with experiment, that many rotational bands must be included in order to obtain a sufficiently representative selection of K quantum numbers, and that the levels of each band must be extended to appropriately high values of angular momentum. 8 references.
Date: August 29, 1984
Creator: Gardner, M. A.; Gardner, D. G. & Hoff, R. W.
System: The UNT Digital Library
An Alternative Lattice for the Spallation Neutron Source Accumulator Ring. (open access)

An Alternative Lattice for the Spallation Neutron Source Accumulator Ring.

As a key component of the Spallation Neutron Source (SNS) Project, the Accumulator Ring will collect the proton beam from the SNS LINAC at an intensity of 2 x 10{sup 14} per pulse at 60 Hz for a total power of 2 MW, exceeding present performance value of existing facilities. Requirements of minimum beam loss for hands-on maintenance and flexibility for future upgrade are essential for the lattice design. In this paper, we study an alternative lattice emphasizing various injection schemes and flexibility for future upgrade. Working points, sextupole families for chromaticity control, and alternate extraction schemes are also considered.
Date: March 29, 1999
Creator: Gardner, C. J.; Lee, Y. Y.; Tsoupas, N. & Wei, J.
System: The UNT Digital Library
Draft versus finished sequence data for DNA and protein diagnostic signature development (open access)

Draft versus finished sequence data for DNA and protein diagnostic signature development

Sequencing pathogen genomes is costly, demanding careful allocation of limited sequencing resources. We built a computational Sequencing Analysis Pipeline (SAP) to guide decisions regarding the amount of genomic sequencing necessary to develop high-quality diagnostic DNA and protein signatures. SAP uses simulations to estimate the number of target genomes and close phylogenetic relatives (near neighbors, or NNs) to sequence. We use SAP to assess whether draft data is sufficient or finished sequencing is required using Marburg and variola virus sequences. Simulations indicate that intermediate to high quality draft with error rates of 10{sup -3}-10{sup -5} ({approx} 8x coverage) of target organisms is suitable for DNA signature prediction. Low quality draft with error rates of {approx} 1% (3x to 6x coverage) of target isolates is inadequate for DNA signature prediction, although low quality draft of NNs is sufficient, as long as the target genomes are of high quality. For protein signature prediction, sequencing errors in target genomes substantially reduce the detection of amino acid sequence conservation, even if the draft is of high quality. In summary, high quality draft of target and low quality draft of NNs appears to be a cost-effective investment for DNA signature prediction, but may lead to underestimation …
Date: October 29, 2004
Creator: Gardner, S N; Lam, M W; Smith, J R; Torres, C L & Slezak, T R
System: The UNT Digital Library
High Intensity Performance of the Brookhaven AGS. (open access)

High Intensity Performance of the Brookhaven AGS.

The Brookhaven AGS provides 24 GeV protons for a multi-user program of fixed-target high energy physics experiments, such as the study of extremely rare Kaon decays. Up to 7 x 10{sup 13} protons are slowly extracted over 2.2 seconds each 5.1 seconds. The muon storage ring of the g-2 experiment is supplied with bunches of 7 x 10{sup 12} protons. Since the completion of the a 1.9 GeV Booster synchrotron and installation of a new high-power rf system and transition jump system in the AGS various modes of operation have been explored to overcome space charge limits and beam instabilities at these extreme beam intensities. Experiments have been done using barrier cavities to enable accumulation of debunched beam in the AGS as a potential path to significantly higher intensities. We report on the present understanding of intensity limitations and prospects for overcoming them.
Date: March 29, 1999
Creator: Ahrens, L. A.; Alessi, J.; Blaskiewicz, M.; Brennan, J. M.; Brown, K.; Gardner, C. et al.
System: The UNT Digital Library
Turn-by-Turn Analysis of Proton and Gold Beams at Injection in the AGS Booster. (open access)

Turn-by-Turn Analysis of Proton and Gold Beams at Injection in the AGS Booster.

In this paper we describe the latest version of a program we have used for several years to acquire and analyze turn-by-turn data from pick-up electrodes in the AGS Booster during injection. The program determines several parameters of the injected beam including the tunes and the position and angle of the incoming beam. Examples are given for both proton and gold injection.
Date: March 29, 1999
Creator: Gardner, C.; Ahrens, L. & Williams, N.
System: The UNT Digital Library
Beam-Loss Driven Design Optimization for the Spallation Neutron Source (SNS) Ring. (open access)

Beam-Loss Driven Design Optimization for the Spallation Neutron Source (SNS) Ring.

This paper summarizes three-stage design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.).
Date: March 29, 1999
Creator: Wei, J.; Beebe-Wang, J.; Blaskiewicz, M.; Cameron, P.; Danby, G.; Gardner, C. J. et al.
System: The UNT Digital Library
Modeling of Long-Range Atmospheric Lasercom Links Between Static and Mobile Platforms (open access)

Modeling of Long-Range Atmospheric Lasercom Links Between Static and Mobile Platforms

We describe modeling and simulation of long-range terrestrial laser communications links between static and mobile platforms. Atmospheric turbulence modeling, along with pointing, tracking and acquisition models are combined to provide an overall capability to estimate communications link performance.
Date: July 29, 2003
Creator: Scharlemann, E T; Breitfeller, E F; Henderson, J R; Kallman, J S; Morris, J R & Ruggiero, A J
System: The UNT Digital Library
China Spallation Neutron Source Design (open access)

China Spallation Neutron Source Design

The China Spallation Neutron Source (CSNS) is an accelerator-based high-power project currently in preparation under the direction of the Chinese Academy of Sciences (CAS). The complex is based on an H- linear accelerator, a rapid cycling proton synchrotron accelerating the beam to 1.6 GeV, a solid tungsten target station, and five initial instruments for spallation neutron applications. The facility will operate at 25 Hz repetition rate with a phase-I beam power of about 120 kW. The major challenge is to build a robust and reliable user's facility with upgrade potential at a fractional of ''world standard'' cost.
Date: January 29, 2007
Creator: Wei, J.
System: The UNT Digital Library
Hadron Spectroscopy and Structure from AdS/CFT (open access)

Hadron Spectroscopy and Structure from AdS/CFT

The AdS/CFT correspondence between conformal field theory and string states in an extended space-time has provided new insights into not only hadron spectra, but also their light-front wavefunctions. We show that there is an exact correspondence between the fifth-dimensional coordinate of anti-de Sitter space z and a specific impact variable {zeta} which measures the separation of the constituents within the hadron in ordinary space-time. This connection allows one to predict the form of the light-front wavefunctions of mesons and baryons, the fundamental entities which encode hadron properties and scattering amplitudes. A new relativistic Schroedinger light-front equation is found which reproduces the results obtained using the fifth-dimensional theory. Since they are complete and orthonormal, the AdS/CFT model wavefunctions can be used as an initial ansatz for a variational treatment or as a basis for the diagonalization of the light-front QCD Hamiltonian. A number of applications of light-front wavefunctions are also discussed.
Date: September 29, 2006
Creator: Brodsky, Stanley J.
System: The UNT Digital Library
Novel Heavy Quark Phenomena in QCD (open access)

Novel Heavy Quark Phenomena in QCD

None
Date: January 29, 2014
Creator: Brodsky, Stanley J.
System: The UNT Digital Library
Study of Longitudinal Injection/Stacking in the SNS Acummulator Ring. (open access)

Study of Longitudinal Injection/Stacking in the SNS Acummulator Ring.

Various longitudinal distributions, resulting from the specific injection and stacking methods, are considered to minimize longitudinal and transverse instabilities and particle losses in SNS accumulator ring. The longitudinal phase space paintings by linac energy ramping, increased linac energy spread and the use of a random phase RF debunching cavity are reported. Bunch lengthening and beam in gap rate as functions of injection energy spread, RF voltage and injection energy error is summarized. Finally, the energy error tolerance is concluded.
Date: March 29, 1999
Creator: Beebe-Wang, J.
System: The UNT Digital Library
Transverse Phase Space Painting for Sns Accumulator Ring Injection. (open access)

Transverse Phase Space Painting for Sns Accumulator Ring Injection.

The result of investigation and comparison of a series of transverse phase space painting schemes for the injection of SNS accumulator ring [1] is reported. In this computer simulation study, the focus is on the creation of closed orbit bumps that give desired distributions at the target. Space charge effects such as tune shift, emittance growth and beam losses are considered. The results of pseudo end-to-end simulations from the injection to the target through the accumulator ring and Ring to Target Beam Transfer (RTBT) system [2] are presented and discussed.
Date: March 29, 1999
Creator: Beebe-Wang, J.; Lee, Y. Y.; Raparia, D. & Wei, J.
System: The UNT Digital Library
Parity Violation Constraints Using Cosmic Microwave Background Polarization Spectra from 2006 and 2007 Observations by the QUaD Polarimeter (open access)

Parity Violation Constraints Using Cosmic Microwave Background Polarization Spectra from 2006 and 2007 Observations by the QUaD Polarimeter

None
Date: November 29, 2011
Creator: Wu, E. Y. S.; Ade, P.; Bock, J.; Bowden, M.; Brown, M. L.; Cahill, G. et al.
System: The UNT Digital Library
Design of a Scanning Gate Microscope for Mesoscopic Electron Systems in a Cryogen-Free Dilution Refrigerator (open access)

Design of a Scanning Gate Microscope for Mesoscopic Electron Systems in a Cryogen-Free Dilution Refrigerator

None
Date: January 29, 2013
Creator: Pelliccione, M.; Sciambi, A.; Bartel, J.; Keller, A. J. & Goldhaber-Gordon, D.
System: The UNT Digital Library
Computational approaches for identification of conserved/unique binding pockets in the A chain of ricin (open access)

Computational approaches for identification of conserved/unique binding pockets in the A chain of ricin

Specific and sensitive ligand-based protein detection assays that employ antibodies or small molecules such as peptides, aptamers, or other small molecules require that the corresponding surface region of the protein be accessible and that there be minimal cross-reactivity with non-target proteins. To reduce the time and cost of laboratory screening efforts for diagnostic reagents, we developed new methods for evaluating and selecting protein surface regions for ligand targeting. We devised combined structure- and sequence-based methods for identifying 3D epitopes and binding pockets on the surface of the A chain of ricin that are conserved with respect to a set of ricin A chains and unique with respect to other proteins. We (1) used structure alignment software to detect structural deviations and extracted from this analysis the residue-residue correspondence, (2) devised a method to compare corresponding residues across sets of ricin structures and structures of closely related proteins, (3) devised a sequence-based approach to determine residue infrequency in local sequence context, and (4) modified a pocket-finding algorithm to identify surface crevices in close proximity to residues determined to be conserved/unique based on our structure- and sequence-based methods. In applying this combined informatics approach to ricin A we identified a conserved/unique pocket …
Date: January 29, 2005
Creator: Ecale Zhou, C L; Zemla, A T; Roe, D; Young, M; Lam, M; Schoeniger, J et al.
System: The UNT Digital Library
Rap1 integrates tissue polarity, lumen formation, and tumorigenicpotential in human breast epithelial cells (open access)

Rap1 integrates tissue polarity, lumen formation, and tumorigenicpotential in human breast epithelial cells

Maintenance of apico-basal polarity in normal breast epithelial acini requires a balance between cell proliferation, cell death, and proper cell-cell and cell-extracellular matrix signaling. Aberrations in any of these processes can disrupt tissue architecture and initiate tumor formation. Here we show that the small GTPase Rap1 is a crucial element in organizing acinar structure and inducing lumen formation. Rap1 activity in malignant HMT-3522 T4-2 cells is appreciably higher than in S1 cells, their non-malignant counterparts. Expression of dominant-negative Rap1 resulted in phenotypic reversion of T4-2 cells, led to formation of acinar structures with correct apico-basal polarity, and dramatically reduced tumor incidence despite the persistence of genomic abnormalities. The resulting acini contained prominent central lumina not observed when other reverting agents were used. Conversely, expression of dominant-active Rap1 in T4-2 cells inhibited phenotypic reversion and led to increased invasiveness and tumorigenicity. Thus, Rap1 acts as a central regulator of breast architecture, with normal levels of activation instructing apical polarity during acinar morphogenesis, and increased activation inducing tumor formation and progression to malignancy.
Date: September 29, 2006
Creator: Itoh, Masahiko; Nelson, Celeste M.; Myers, Connie A. & Bissell,Mina J.
System: The UNT Digital Library
High energy negative deuterium beams using double charge-exchange or surface production (open access)

High energy negative deuterium beams using double charge-exchange or surface production

Experimental and theoretical research on production of negative ion beams is described. Results from a double charge-exchange experiment include 10 ms pulses of 100 ma of D/sup -/ accelerated to 60 kV. Equilibrium fractions of D/sup -/ in several metal vapors are presented. Mechanisms and measurements of D/sup -/ on surfaces are described, and a scheme is shown for producing high current, high energy beams originating on surfaces.
Date: November 29, 1977
Creator: Hooper, E. B. Jr.; Anderson, O. A.; Orzechowski, T. & Poulsen, P.
System: The UNT Digital Library
Femtoscopy in Relativistic Heavy Ion Collisions (open access)

Femtoscopy in Relativistic Heavy Ion Collisions

Analyses of two-particle correlations have provided the chief means for determining spatio-temporal characteristics of relativistic heavy ion collisions. We discuss the theoretical formalism behind these studies and the experimental methods used in carrying them out. Recent results from RHIC are put into context in a systematic review of correlation measurements performed over the past two decades. The current understanding of these results are discussed in terms of model comparisons and overall trends.
Date: July 29, 2005
Creator: Lisa, M; Pratt, S; Soltz, R A & Wiedemann, U
System: The UNT Digital Library
Injection of Gold Ions in the AGS Booster With Linear Coupling. (open access)

Injection of Gold Ions in the AGS Booster With Linear Coupling.

Linear Coupling, introduced by skew quadrupoles, has been used for several years to enhance the multi-turn injection efficiency of gold and other heavy ions in the AGS Booster. In this paper we describe our latest measurements of the injection process and compare with models.
Date: March 29, 1999
Creator: Gardne, C.; Ahrens, L.; Roser, T. & Zeno, K.
System: The UNT Digital Library
Summary of talks third annual hot dry rock geothermal information conference (open access)

Summary of talks third annual hot dry rock geothermal information conference

Three basic comparisons can be made between weapon system development and energy system development in the US--driving factors, system lifetime, and development time. Weapon system development and response is determined by a perceived threat to national security. Because the threat can change radically in this high technology atmosphere, weapon systems are usually designed for a 5 to 20 year lifetime. Development time from idea to capability is about 20 years on the average. In contrast, energy system development has been influenced by economics--demand, supply, return on investment--until the recent threat created by our dependence on oil. Energy systems are expected to operate 20 to 50 years and even longer. Development time is correspondingly long, i.e., 40 years from idea to large-scale use. The US needs to adopt a ''defense-oriented'' approach to protect its threatened energy security. Geothermal energy from hot dry rock is a new concept. The Hot Dry Rock Program is designed to minimize development time and may become a prime example of how a recognized threat to energy security can be answered by combined government/industry effort.
Date: October 29, 1980
Creator: Gaddy, James
System: The UNT Digital Library