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A Parallel Code for Lifetime Simulations in Hadron Storage Rings in the Presence of Parasitic Beam-Beam Interactions (open access)

A Parallel Code for Lifetime Simulations in Hadron Storage Rings in the Presence of Parasitic Beam-Beam Interactions

The usual approach to predict particle loss in storage rings in the presence of nonlinearities consists in the determination of the dynamic aperture of the machine. This method, however, will not directly predict the lifetimes of beams. We have developed a code which can, by parallelization and careful speed optimization, predict lifetimes in the presence of 100 parasitic beam-beam crossings by tracking > 10{sup 10} particles-turns. An application of this code to the anti-proton lifetime in the Tevatron at injection is discussed.
Date: March 17, 2008
Creator: Kabel, A. C.; Cai, Y.; Erdelyi, B.; Sen, T. & Xiao, M.
Object Type: Article
System: The UNT Digital Library
Beam Dynamics Studies for the SPARC Project (open access)

Beam Dynamics Studies for the SPARC Project

The aim of the SPARC project, is to promote an R&D activity oriented to the development of a high brightness photoinjector to drive SASE-FEL experiments. We discuss in this paper the status of the beam dynamics simulation activities.
Date: March 17, 2008
Creator: Ferrario, M.; Biagini, Maria E.; Boscolo, M.; Fusco, V.; Guiducci, S.; Migliorati, M. et al.
Object Type: Article
System: The UNT Digital Library
Positron Beam Propagation in a Meter Long Plasma Channel (open access)

Positron Beam Propagation in a Meter Long Plasma Channel

Recent experiments and simulations have shown that positron beams propagating in plasmas can be focused and also create wakes with large accelerating gradients. For similar parameters, the wakes driven by positron beams are somewhat smaller compared to the case of an electron beam. Simulations have shown that the wake amplitude can be increased if the positron beam is propagated in a hollow plasma channel (Ref. 1). This paper, compares experimentally, the propagation and beam dynamics of a positron beam in a meter scale homogeneous plasma, to a positron beam hollow channel plasma. The results show that positron beams in hollow channels are less prone to distortions and deflections. Hollow channels were observed to guide the positron beam onto the channel axis. Beam energy loss was also observed implying the formation of a large wake amplitude. The experiments were carried out as part of the E-162 plasma wakefield experiments at SLAC.
Date: March 17, 2008
Creator: Marsh, K. A.; Blue, B. E.; Clayton, C. E.; Joshi, C.; Mori, W. B.; Decker, F. -J. et al.
Object Type: Article
System: The UNT Digital Library
Renewable Energy Development on Fort Mojave Reservation Feasiblity Study (open access)

Renewable Energy Development on Fort Mojave Reservation Feasiblity Study

The Ft. Mojave tribe, whose reservation is located along the Colorado River in the states of Arizona, California, and Nevada near the point where all three states meet, has a need for increased energy supplies. This need is a direct result of the aggressive and successful economic development projects undertaken by the tribe in the last decade. While it is possible to contract for additional energy supplies from fossil fuel sources it was the desire of the tribal power company, AHA MACAV Power Service (AMPS) to investigate the feasibility and desirability of producing power from renewable sources as an alternative to increased purchase of fossil fuel generated power and as a possible enterprise to export green power. Renewable energy generated on the reservation would serve to reduce the energy dependence of the tribal enterprises on off reservation sources of energy and if produced in excess of reservation needs, add a new enterprise to the current mix of economic activities on the reservation. Renewable energy development would also demonstrate the tribe’s support for improving environmental quality, sustainability, and energy independence both on the reservation and for the larger community.
Date: March 17, 2008
Creator: Russell Gum, ERCC analytics LLC
Object Type: Report
System: The UNT Digital Library
Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring (open access)

Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring

Recent beam physics studies on the two-stream e-p instability at the LANL proton storage ring (PSR) have focused on the role of the electron cloud generated in quadrupole magnets where primary electrons, which seed beam-induced multipacting, are expected to be largest due to grazing angle losses from the beam halo. A new diagnostic to measure electron cloud formation and trapping in a quadrupole magnet has been developed, installed, and successfully tested at PSR. Beam studies using this diagnostic show that the 'prompt' electron flux striking the wall in a quadrupole is comparable to the prompt signal in the adjacent drift space. In addition, the 'swept' electron signal, obtained using the sweeping feature of the diagnostic after the beam was extracted from the ring, was larger than expected and decayed slowly with an exponential time constant of 50 to 100 {micro}s. Other measurements include the cumulative energy spectra of prompt electrons and the variation of both prompt and swept electron signals with beam intensity. Experimental results were also obtained which suggest that a good fraction of the electrons observed in the adjacent drift space for the typical beam conditions in the 2006 run cycle were seeded by electrons ejected from the …
Date: March 17, 2008
Creator: Macek, Robert J.; Browman, Andrew A.; Ledford, John E.; Borden, Michael J.; O'Hara, James F.; McCrady, Rodney C. et al.
Object Type: Article
System: The UNT Digital Library
Coupling Correction and Beam Dynamics at Ultralow Vertical Emittance in the ALS (open access)

Coupling Correction and Beam Dynamics at Ultralow Vertical Emittance in the ALS

For synchrotron light sources and for damping rings of linear colliders it is important to be able to minimize the vertical emittance and to correct the spurious vertical dispersion. This allows one to maximize the brightness and/or the luminosity. A commonly used tool to measure the skew error distribution is the analysis of orbit response matrices using codes like LOCO. Using the new Matlab version of LOCO and 18 newly installed power supplies for individual skew quadrupoles at the ALS the emittance ratio could be reduced below 0.1% at 1.9 GeV yielding a vertical emittance of about 5 pm. At those very low emittances, additional effects like intra beam scattering become more important, potentially limiting the minimum emittance for machine like the damping rings of linear colliders.
Date: March 17, 2008
Creator: Steier, Christoph; Robin, D.; Wolski, A.; Portmann, G.; Safranek, J. & /LBL, Berkeley /SLAC
Object Type: Article
System: The UNT Digital Library
General Relativistic Effects in Atom Interferometry (open access)

General Relativistic Effects in Atom Interferometry

Atom interferometry is now reaching sufficient precision to motivate laboratory tests of general relativity. We begin by explaining the non-relativistic calculation of the phase shift in an atom interferometer and deriving its range of validity. From this we develop a method for calculating the phase shift in general relativity. This formalism is then used to find the relativistic effects in an atom interferometer in a weak gravitational field for application to laboratory tests of general relativity. The potentially testable relativistic effects include the non-linear three-graviton coupling, the gravity of kinetic energy, and the falling of light. We propose experiments, one currently under construction, that could provide a test of the principle of equivalence to 1 part in 10{sup 15} (300 times better than the present limit), and general relativity at the 10% level, with many potential future improvements. We also consider applications to other metrics including the Lense-Thirring effect, the expansion of the universe, and preferred frame and location effects.
Date: March 17, 2008
Creator: Dimopoulos, Savas; /Stanford U., Phys. Dept.; Graham, Peter W.; /SLAC /Stanford U., Phys. Dept.; Hogan, Jason M.; Kasevich, Mark A. et al.
Object Type: Article
System: The UNT Digital Library
Groundwater Level Status Report for Fiscal Year 2007 - Los Alamos National Laboratory (open access)

Groundwater Level Status Report for Fiscal Year 2007 - Los Alamos National Laboratory

The status of groundwater level monitoring at Los Alamos National Laboratory in Fiscal Year 2007 is provided in this report. The Groundwater Level Monitoring Project was instituted in 2005 to provide a framework for the collection and processing of quality controlled groundwater level data. This report summarizes groundwater level data for 166 monitoring wells, including 45 regional aquifer wells, 25 intermediate wells, and 96 alluvial wells, and 11 water supply wells. Pressure transducers were installed in 133 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well.
Date: March 17, 2008
Creator: Shannon P. Allen, Richard J. Koch
Object Type: Report
System: The UNT Digital Library
Parallel Simulation Algorithms for the Three Dimensional Strong-Strong Beam-Beam Interaction (open access)

Parallel Simulation Algorithms for the Three Dimensional Strong-Strong Beam-Beam Interaction

The strong-strong beam-beam effect is one of the most important effects limiting the luminosity of ring colliders. Little is known about it analytically, so most studies utilize numeric simulations. The two-dimensional realm is readily accessible to workstation-class computers (cf.,e.g.,[1, 2]), while three dimensions, which add effects such as phase averaging and the hourglass effect, require vastly higher amounts of CPU time. Thus, parallelization of three-dimensional simulation techniques is imperative; in the following we discuss parallelization strategies and describe the algorithms used in our simulation code, which will reach almost linear scaling of performance vs. number of CPUs for typical setups.
Date: March 17, 2008
Creator: Kabel, A. C.
Object Type: Article
System: The UNT Digital Library
Vacuum Insulator Development for the Dielectric Wall Accelerator (open access)

Vacuum Insulator Development for the Dielectric Wall Accelerator

At Lawrence Livermore National Laboratory, we are developing a new type of accelerator, known as a Dielectric Wall Accelerator, in which compact pulse forming lines directly apply an accelerating field to the beam through an insulating vacuum boundary. The electrical strength of this insulator may define the maximum gradient achievable in these machines. To increase the system gradient, we are using 'High Gradient Insulators' composed of alternating layers of dielectric and metal for the vacuum insulator. In this paper, we present our recent results from experiment and simulation, including the first test of a High Gradient Insulator in a functioning Dielectric Wall Accelerator cell.
Date: March 17, 2008
Creator: Harris, J. R.; Blackfield, D.; Caporaso, G. J.; Chen, Y.; Hawkins, S.; Kendig, M. et al.
Object Type: Article
System: The UNT Digital Library
Letter Report to Address Comments on the Closure Report for Corrective Action Unit 224: Decon Pad and Septic Systems, Nevada Test Site, Nevada, Revision 0, March 2008 (open access)

Letter Report to Address Comments on the Closure Report for Corrective Action Unit 224: Decon Pad and Septic Systems, Nevada Test Site, Nevada, Revision 0, March 2008

The Closure Report (CR) for Corrective Action Unit (CAU) 224, Decon Pad and Septic Systems, was approved by the Nevada Department of Environmental Protection (NDEP) on November 01, 2007. The approval letter contained the following two comments: Comment 1--For 06-05-01, 06-17-04, 06-23-01 provide evidence that the 6 inch VCP pipe originating from building CP-2 is no longer active and sealed to prevent possible future contamination. Comment 2--For the area that includes 06-03-01, provide evidence that active lines are no longer feeding the North and South lagoons and have been sealed to prevent possible future contamination. To address these comments, closure documentation was reviewed, and site visits were conducted to locate and document the areas of concern. Additional fieldwork was conducted in March 2008 to seal the lines and openings described in the two comments. Photographs were taken of the closed drains and lines to document that the NDEP comments were adequately addressed and potential inadvertent discharge to the environment has been eliminated. Investigation and closure documentation was reviewed to identify the locations of potential drains, lines, and other features that could receive and/or transmit liquid. Based on the investigation findings and subsequent closure activities, no openings, distribution boxes, or other …
Date: March 17, 2008
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Electron Cloud Mitigation in the Spallation Neutron Source Ring (open access)

Electron Cloud Mitigation in the Spallation Neutron Source Ring

The Spallation Neutron Source (SNS) accumulator ring is designed to accumulate, via H{sup -} injection, protons of 2 MW beam power at 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity, electron-cloud is expected to be one of the intensity-limiting mechanisms that complicate ring operations. This paper summarizes mitigation strategy adopted in the design, both in suppressing electron-cloud formation and in enhancing Landau damping, including tapered magnetic field and monitoring system for the collection of stripped electrons at injection, TiN coated beam chamber for suppression of the secondary yield, clearing electrodes dedicated for the injection region and parasitic on BPMs around the ring, solenoid windings in the collimation region, and planning of vacuum systems for beam scrubbing upon operation.
Date: March 17, 2008
Creator: Wei, J.; Blaskiewicz, Michael; Brodowski, J.; Cameron, P.; Davino, Daniele; Fedotov, A. et al.
Object Type: Article
System: The UNT Digital Library
DESIGN OF AN OPTICAL DIFFERACTION RADIATION BEAM SIZE MONITOR AT SLAC FETB (open access)

DESIGN OF AN OPTICAL DIFFERACTION RADIATION BEAM SIZE MONITOR AT SLAC FETB

We design a single bunch transverse beam size monitor which will be tested to measure the 28.5 GeV electron/positron beam at the SLAC FFTB beam line. The beam size monitor uses the CCD images of the interference pattern of the optical diffraction radiation from two slit edges which are placed close to the beam path. In this method, destruction of the accelerated electron/positron beam bunches due to the beam size monitoring is negligible, which is vital to the operation of the Linear Collider project.
Date: March 17, 2008
Creator: Fukui, Y.; Cline, D.; Zhou, F.; Tobiyama, M.; Urakawa, J.; Bolton, P. R. et al.
Object Type: Article
System: The UNT Digital Library
Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2007 Annual Report. (open access)

Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2007 Annual Report.

This document is the first annual report for the study titled 'Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta in the Lower Columbia River'. Hereafter, we refer to this research as the Tidal Freshwater Monitoring (TFM) Study. The study is part of the research, monitoring, and evaluation effort developed by the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS). The project is performed under the auspices of the Northwest Power and Conservation Council's Columbia Basin Fish and Wildlife Program. The goal of the 2007-2009 Tidal Freshwater Monitoring Study is to answer the following questions: In what types of habitats within the tidal freshwater area of the lower Columbia River and estuary (LCRE; Figure 1) are yearling and subyearling salmonids found, when are they present, and under what environmental conditions?1 And, what is the ecological importance2 of shallow (0-5 m) tidal freshwater habitats to the recovery of Upper Columbia River spring Chinook salmon and steelhead and Snake River fall Chinook salmon? Research in …
Date: March 17, 2008
Creator: Sobocinski, Kathryn; Johnson, Gary & Sather, Nichole
Object Type: Report
System: The UNT Digital Library
Simulation of Alpha-Channeling in Mirror Machines (open access)

Simulation of Alpha-Channeling in Mirror Machines

Applying α-channeling techniques to mirror machines can significantly increase their effective reactivity, thus making open configurations more advantageous for practical fusion. A large fraction of α particle energy can be extracted using rf waves. Effects employed to cool α particles can also in principle be used to heat the fusion ions; the possibility to design a configuration of rf waves which could be used to perform both tasks is demonstrated.
Date: March 17, 2008
Creator: A.I. Zhmoginov, N.J. Fisch
Object Type: Report
System: The UNT Digital Library
[Letter to Al Daniels from Paul E. Scott] (open access)

[Letter to Al Daniels from Paul E. Scott]

Letter to Al Daniels from Paul E. Scott on March 17, 2008, discussing about making a financial donation to Equality Texas Foundation.
Date: March 17, 2008
Creator: unknown
Object Type: Letter
System: The UNT Digital Library
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 93, No. 107, Ed. 1 Monday, March 17, 2008 (open access)

Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 93, No. 107, Ed. 1 Monday, March 17, 2008

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date: March 17, 2008
Creator: Mattox, Jami
Object Type: Newspaper
System: The Gateway to Oklahoma History
The Baytown Sun (Baytown, Tex.), Vol. 88, No. 77, Ed. 1 Monday, March 17, 2008 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 88, No. 77, Ed. 1 Monday, March 17, 2008

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: March 17, 2008
Creator: Clements, Clifford E.
Object Type: Newspaper
System: The Portal to Texas History
The Express-Star (Chickasha, Okla.), Ed. 1 Monday, March 17, 2008 (open access)

The Express-Star (Chickasha, Okla.), Ed. 1 Monday, March 17, 2008

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date: March 17, 2008
Creator: Wilson, Chris
Object Type: Newspaper
System: The Gateway to Oklahoma History
The Altus Times (Altus, Okla.), Vol. 109, No. 247, Ed. 1 Monday, March 17, 2008 (open access)

The Altus Times (Altus, Okla.), Vol. 109, No. 247, Ed. 1 Monday, March 17, 2008

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: March 17, 2008
Creator: Bush, Michael
Object Type: Newspaper
System: The Gateway to Oklahoma History