High Temperature Superconducting Magnets for Efficient Low Energy Beam Transport Systems (open access)

High Temperature Superconducting Magnets for Efficient Low Energy Beam Transport Systems

None
Date: May 1, 2012
Creator: Popovic, M.; /Fermilab; Flanagan, G.; Johnson, R. P.; Nipper, J. H. & /MUONS Inc., Batavia
System: The UNT Digital Library
Experimental Generation of a Double-bunch Electron Beam by Transverse-to-Longitudinal Phase Space Exchange (open access)

Experimental Generation of a Double-bunch Electron Beam by Transverse-to-Longitudinal Phase Space Exchange

None
Date: May 1, 2012
Creator: Maxwell, T.; Piot, P.AFFILIATION = Northern Illinoi U.; /Fermilab; Ruan, J.; Lumpkin, A.; Thurman-Keup, R. et al.
System: The UNT Digital Library
Observation of Instabilities of Coherent Transverse Oscillations in the Fermilab Booster (open access)

Observation of Instabilities of Coherent Transverse Oscillations in the Fermilab Booster

The Fermilab Booster - built more than 40 years ago - operates well above the design proton beam intensity of 4 {center_dot} 10{sup 12} ppp. Still, the Fermilab neutrino experiments call for even higher intensity exceeding 5.5 {center_dot} 10{sup 12} ppp. A multitude of intensity related effects must be overcome in order to meet this goal including suppression of coherent dipole instabilities of transverse oscillations which manifest themselves as a sudden drop in the beam current. In this report we present the results of observation of these instabilities at different tune, coupling and chromaticity settings and discuss possible cures.
Date: May 1, 2012
Creator: Alexahin, Y.; Eddy, N.; Gianfelice-Wendt, E.; Lebedev, V.; Marsh, W.; Pellico, W. et al.
System: The UNT Digital Library
Simulation study of electron response amplification in coherent electron cooling (open access)

Simulation study of electron response amplification in coherent electron cooling

In Coherent Electron Cooling (CEC), it is essential to study the amplification of electron response to a single ion in the FEL process, in order to proper align the electron beam and the ion beam in the kicker to maximize the cooling effect. In this paper, we use Genesis to simulate the amplified electron beam response of single ion in FEL amplification process, which acts as Green's function of the FEL amplifier.
Date: May 20, 2012
Creator: Y., Hao & Litvinenko, V. N.
System: The UNT Digital Library
Phase Fluctuations and the Absence of Topological Defects in Photo-excited Charge Ordered Nickelate (open access)

Phase Fluctuations and the Absence of Topological Defects in Photo-excited Charge Ordered Nickelate

The dynamics of an order parameter's amplitude and phase determines the collective behaviour of novel states emerging in complex materials. Time- and momentum-resolved pump-probe spectroscopy, by virtue of measuring material properties at atomic and electronic time scales out of equilibrium, can decouple entangled degrees of freedom by visualizing their corresponding dynamics in the time domain. Here we combine time-resolved femotosecond optical and resonant X-ray diffraction measurements on charge ordered La{sub 1.75}Sr{sub 0.25}NiO{sub 4} to reveal unforeseen photoinduced phase fluctuations of the charge order parameter. Such fluctuations preserve long-range order without creating topological defects, distinct from thermal phase fluctuations near the critical temperature in equilibrium. Importantly, relaxation of the phase fluctuations is found to be an order of magnitude slower than that of the order parameter's amplitude fluctuations, and thus limits charge order recovery. This new aspect of phase fluctuations provides a more holistic view of the phase's importance in ordering phenomena of quantum matter.
Date: May 15, 2012
Creator: Lee, W.S.; Chuang, Y.D.; Moore, R.G.; Zhu, Y.; Patthey, L.; Trigo, M. et al.
System: The UNT Digital Library
Study of Electronegative Gas Effect in Beam Induced Plasma (open access)

Study of Electronegative Gas Effect in Beam Induced Plasma

None
Date: May 1, 2012
Creator: Freemire, B.; Torun, Y.; Hanlet, P.; Leonova, M.; Chung, M.; Collura, M. G. et al.
System: The UNT Digital Library
Phase Transition in BCx system under High-Pressure and High-Temperature: Synthesis of Cubic Dense BC3 Nanostructured Phase (open access)

Phase Transition in BCx system under High-Pressure and High-Temperature: Synthesis of Cubic Dense BC3 Nanostructured Phase

None
Date: May 26, 2012
Creator: Zinin, P. V.; Ming, L. C.; Ishii, H. A.; Jia, R.; Acosta, T. & Hellebrand, E.
System: The UNT Digital Library
PHYSICS RESULTS OF THE NSLS-II LINAC FRONT END TEST STAND (open access)

PHYSICS RESULTS OF THE NSLS-II LINAC FRONT END TEST STAND

The Linac Front End Test Stand (LFETS) was installed at the Source Development Laboratory (SDL) in the fall of 2011 in order to test the Linac Front End. The goal of these tests was to test the electron source against the specifications of the linac. In this report, we discuss the results of these measurements and the effect on linac performance.
Date: May 20, 2012
Creator: P., Fliller R.; Gao, F.; Yang, X.; Rose, J.; Shaftan, T. & Piel, C
System: The UNT Digital Library
Stochastic cooling in RHIC (open access)

Stochastic cooling in RHIC

The full 6-dimensional [x,x'; y,y'; z,z'] stochastic cooling system for RHIC was completed and operational for the FY12 Uranium-Uranium collider run. Cooling enhances the integrated luminosity of the Uranium collisions by a factor of 5, primarily by reducing the transverse emittances but also by cooling in the longitudinal plane to preserve the bunch length. The components have been deployed incrementally over the past several runs, beginning with longitudinal cooling, then cooling in the vertical planes but multiplexed between the Yellow and Blue rings, next cooling both rings simultaneously in vertical (the horizontal plane was cooled by betatron coupling), and now simultaneous horizontal cooling has been commissioned. The system operated between 5 and 9 GHz and with 3 x 10{sup 8} Uranium ions per bunch and produces a cooling half-time of approximately 20 minutes. The ultimate emittance is determined by the balance between cooling and emittance growth from Intra-Beam Scattering. Specific details of the apparatus and mathematical techniques for calculating its performance have been published elsewhere. Here we report on: the method of operation, results with beam, and comparison of results to simulations.
Date: May 20, 2012
Creator: M., Brennan J.; Blaskiewicz, M. & Mernick, K.
System: The UNT Digital Library
Kink instability suppression with stochastic cooling pickup and kicker (open access)

Kink instability suppression with stochastic cooling pickup and kicker

The kink instability is one of the major beam dynamics issues of the linac-ring based electron ion collider. This head-tail type instability arises from the oscillation of the electron beam inside the opposing ion beam. It must be suppressed to achieve the desired luminosity. There are various ways to suppress the instability, such as tuning the chromaticity in the ion ring or by a dedicated feedback system of the electron beam position at IP, etc. However, each method has its own limitation. In this paper, we will discuss an alternative opportunity of suppressing the kink instability of the proposed eRHIC at BNL using the existing pickup-kicker system of the stochastic cooling system in RHIC.
Date: May 20, 2012
Creator: Y., Hao; Blaskiewicz, M.; Litvinenko, V. N. & Ptitsyn, V.
System: The UNT Digital Library
Alternative Cavity for H E Part of the Project X linac (open access)

Alternative Cavity for H E Part of the Project X linac

This report is about an Alternative Cavity for He Part of the Project X linac.
Date: May 1, 2012
Creator: Lunin, A.; Saini, A.; Solyak, N.; Sukhanov, A. I. & Yakovlev, V. P.
System: The UNT Digital Library
Distinguishing Pu Metal From Pu Oxide Using Fast Neutron Counting (open access)

Distinguishing Pu Metal From Pu Oxide Using Fast Neutron Counting

We describe a method for simultaneously determining the {alpha}-ratio and k{sub eff} for fissile materials using fast neutrons. Our method is a generalization of the Hage-Cifarrelli method for determining k{sub eff} for fissile assemblies which utilizes the shape of the fast neutron spectrum. In this talk we illustrate the method using Monte Carlo simulations of the fast neutrons generated in PuO{sub 2} to calculate the fast neutron spectrum and Feynman correlations.
Date: May 29, 2012
Creator: Verbeke, J M; Chapline, G F; Nakae, L; Wurtz, R & Sheets, S
System: The UNT Digital Library
Rapid Determination Of Radiostrontium In Large Soil Samples (open access)

Rapid Determination Of Radiostrontium In Large Soil Samples

A new method for the determination of radiostrontium in large soil samples has been developed at the Savannah River Environmental Laboratory (Aiken, SC, USA) that allows rapid preconcentration and separation of strontium in large soil samples for the measurement of strontium isotopes by gas flow proportional counting. The need for rapid analyses in the event of a Radiological Dispersive Device (RDD) or Improvised Nuclear Device (IND) event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. The method employs a novel pre-concentration step that utilizes an iron hydroxide precipitation (enhanced with calcium phosphate) followed by a final calcium fluoride precipitation to remove silicates and other matrix components. The pre-concentration steps, in combination with a rapid Sr Resin separation using vacuum box technology, allow very large soil samples to be analyzed for {sup 89,90}Sr using gas flow proportional counting with a lower method detection limit. The calcium fluoride precipitation eliminates column flow problems typically associated with large amounts of silicates in large soil samples.
Date: May 24, 2012
Creator: Maxwell, Sherrod L.; Culligan, Brian K. & Shaw, Patrick J.
System: The UNT Digital Library
Measurements of Magnetic Permeability of Soft Steel at High Frequencies (open access)

Measurements of Magnetic Permeability of Soft Steel at High Frequencies

None
Date: May 1, 2012
Creator: Tokpanov, Yu.; Lebedev, V. & Pellico, W.
System: The UNT Digital Library
What Scientific Applications can Benefit from Hardware Transactional Memory? (open access)

What Scientific Applications can Benefit from Hardware Transactional Memory?

None
Date: May 7, 2012
Creator: Schindewolf, M; Bihari, B; Gyllenhaal, J; Schulz, M; Wang, A & Karl, W
System: The UNT Digital Library
Coupling Impedance of a Periodic Array of Diaphragms (Erratum) (open access)

Coupling Impedance of a Periodic Array of Diaphragms (Erratum)

A method is presented for calculating the high-frequency longitudinal and transverse coupling impedances in a periodic array of diaphragms in a circular perfectly conducting pipe. The method is based on Weinstein's theory of diffraction of a plane electromagnetic wave on a stack of halfplanes. Using Weinstein's solution, it is shown that the problem of finding the beam field in the pipe reduces to an effective boundary condition at the radius of the diaphragms that couples the longitudinal electric field with the azimuthal magnetic one. Solving Maxwell's equations with this boundary condition leads to simple formulae for Z{sub long} and Z{sub tr}. A good agreement with a numerical solution of the problem found by other authors is demonstrated.
Date: May 24, 2012
Creator: Stupakov, G. V.
System: The UNT Digital Library
Novel technique of suppressing TBBU in high-energy ERLs (open access)

Novel technique of suppressing TBBU in high-energy ERLs

Energy recovery linacs (ERLs) are an emerging generation of accelerators that promise to revolutionize the fields of high-energy physics and photon sciences. These accelerators combine the advantages of linear accelerators with that of storage rings, and augur the delivery of electron beams of unprecedented power and quality. However, one potential weakness of these devices is transverse beam break-up instability that could severely limit the available beam current. In this paper, I propose a novel method of suppressing these dangerous effects using the chromaticity of the transverse motion. In this short paper I am able only to touch the surface of the method and a complete description of the method with all relevant derivations can be found in [1].
Date: May 20, 2012
Creator: V., Litvinenko
System: The UNT Digital Library
A User Perspective of High-Performance Computing on the Cloud (open access)

A User Perspective of High-Performance Computing on the Cloud

None
Date: May 3, 2012
Creator: Marathe, A.; Lowenthal, D.; Rountree, B.; Yuan, X.; Schulz, M. & de Supinski, B.
System: The UNT Digital Library
Toward Real-time Modeling of Human Heart Ventricles at Cellular Resolution: Multi-hour Simulation of Drug-induced Arrhythmias (open access)

Toward Real-time Modeling of Human Heart Ventricles at Cellular Resolution: Multi-hour Simulation of Drug-induced Arrhythmias

None
Date: May 1, 2012
Creator: Mirin, A. A.; Richards, D. F.; Glosli, J. N.; Draeger, E. W.; Chan, B.; Fattebert, J. et al.
System: The UNT Digital Library
Design Studies of a Dipole with Elliptical Aperture for the Muon Collider Storage Ring (open access)

Design Studies of a Dipole with Elliptical Aperture for the Muon Collider Storage Ring

In this paper we describe the main design issues of dipoles with an elliptical aperture taking into consideration the field and field quality. The discussion is extended presenting a combined function magnet design. The temperature margin and the forces in the coils are present as well.
Date: May 1, 2012
Creator: Palmer, R. B.; Lopes, M. L.; Kashikhin, V. V.; Tompkins, J. C. & Zlobin, A. V.
System: The UNT Digital Library
Design, simulation and conditioning of the fundamental power couplers for BNL SRF gun (open access)

Design, simulation and conditioning of the fundamental power couplers for BNL SRF gun

The 704 MHz SRF gun for the BNL Energy Recovery Linac (ERL) prototype uses two fundamental power couplers (FPCs) to deliver up to 1 MW of CW RF power to the half-cell cavity. To prepare the couplers for high-power RF service and process multipacting, the FPCs should be conditioned prior to installation into the gun cryomodule. A room-temperature test stand was configured for conditioning FPCs in full reflection regime with varied phase of the reflecting wave. The FPCs have been conditioned up to 250 kW in pulse mode and 125 kW in CW mode. The multipacting simulations were carried out with Track3P code developed at SLAC. The simulations matched the experimental results very well. This paper presents the FPC RF and thermal design, multipacting simulations and conditioning of the BNL gun FPCs.
Date: May 20, 2012
Creator: Xu, W.; Altinbas, Z.; Belomestnykh, S. & Ben-Zvi, Ilan
System: The UNT Digital Library
Future Vision for Instrumentation, Information and Control Modernization (open access)

Future Vision for Instrumentation, Information and Control Modernization

A Future Vision of a transformed nuclear plant operating model based on an integrated digital environment has been developed as part of the Advanced Instrumentation, Information, and Control (II&C) research pathway, under the Light Water Reactor (LWR) Sustainability Program. This is a research and development program sponsored by the U.S. Department of Energy (DOE), performed in close collaboration with the nuclear utility industry, to provide the technical foundations for licensing and managing the long-term, safe and economical operation of current nuclear power plants. II&C has been identified as a potential life-limiting issue for the domestic LWR fleet in addressing the reliability and aging concerns of the legacy systems in service today. The Future Vision is based on a digital architecture that encompasses all aspects of plant operations and support, integrating plant systems, plant work processes, and plant workers in a seamless digital environment to enhance nuclear safety, increase productivity, and improve overall plant performance. Pilot projects are being conducted as the means for industry to gain confidence in these new technologies for use in nuclear plant work activities. The pilot projects introduce new digital technologies into the nuclear plant operating environment at host operating plants to demonstrate and validate them …
Date: May 1, 2012
Creator: Thomas, Ken D.
System: The UNT Digital Library
Alignment and Aperture Scan at the Fermilab Booster (open access)

Alignment and Aperture Scan at the Fermilab Booster

The Fermilab Booster is currently in the process of an intensity upgrade referred to as the Proton Improvement Plan (PIP). The goal of PIP is to have the Booster provide a proton beam flux of 2 x 10{sup 17} protons/hour. This is almost double the current operation of 1.1 x 10{sup 17} protons/hour. Beam losses in the machine due to the increased flux will create larger integrated doses on aperture limiting components that will need to be mitigated. The Booster accelerates beam from 400 MeV to 8 GeV at a rep rate of 15hz and then extracts beam to the Main Injector. Several percent of the beam is lost within 3 msec after injection in the early part of acceleration. The aperture at injection energy was recently measured using corrector scans. Along with magnet survey data and aperture scan data a plan to realign the magnets in the Booster was developed and implemented in May 2012. The beam studies, analysis of the scan and alignment data, and the result of the magnet moves are presented.
Date: May 1, 2012
Creator: Seiya, K.; Lackey, J.; Marsh, W.; Pellico, W.; Still, D.; Triplet, K. et al.
System: The UNT Digital Library
Incorporation of Multi-Member Substructure Capabilities in FAST for Analysis of Offshore Wind Turbines: Preprint (open access)

Incorporation of Multi-Member Substructure Capabilities in FAST for Analysis of Offshore Wind Turbines: Preprint

FAST, developed by the National Renewable Energy Laboratory (NREL), is an aero-hydro-servo-elastic tool widely used for analyzing onshore and offshore wind turbines. This paper discusses recent modifications made to FAST to enable the examination of offshore wind turbines with fixed-bottom, multi-member support structures (which are commonly used in transitional-depth waters).; This paper addresses the methods used for incorporating the hydrostatic and hydrodynamic loading on multi-member structures in FAST through its hydronamic loading module, HydroDyn. Modeling of the hydrodynamic loads was accomplished through the incorporation of Morison and buoyancy loads on the support structures. Issues addressed include how to model loads at the joints of intersecting members and on tapered and tilted members of the support structure. Three example structures are modeled to test and verify the solutions generated by the modifications to HydroDyn, including a monopile, tripod, and jacket structure. Verification is achieved through comparison of the results to a computational fluid dynamics (CFD)-derived solution using the commercial software tool STAR-CCM+.
Date: May 1, 2012
Creator: Song, H.; Robertson, A.; Jonkman, J. & Sewell, D.
System: The UNT Digital Library