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Booster Synchrotron RF System Upgrade for SPEAR3 (open access)

Booster Synchrotron RF System Upgrade for SPEAR3

Recent progress at the SPEAR3 includes the increase in stored current from 100 mA to 200 mA and top-off injection to allow beamlines to stay open during injection. Presently the booster injects 3.0 GeV beam to SPEAR3 three times a day. The stored beam decays to about 150 mA between the injections. The growing user demands are to increase the stored current to the design value of 500 mA, and to maintain it at a constant value within a percent or so. To achieve this goal the booster must inject once every few minutes. For improved injection efficiency, all RF systems at the linac, booster and SPEAR3 need to be phase-locked. The present booster RF system is basically a copy of the SPEAR2 RF system with 358.5 MHz and 40 kW peak RF power driving a 5-cell RF cavity for 1.0 MV gap voltage. These requirements entail a booster RF system upgrade to a scaled down version of the SPEAR3 RF system of 476.3 MHz with 1.2 MW cw klystron output power capabilities. We will analyze each subsystem option for their merits within budgetary and geometric space constraints. A substantial portion of the system will come from the decommissioned PEP-II …
Date: July 6, 2012
Creator: Park, Sanghyun & Corbett, Jeff
Object Type: Article
System: The UNT Digital Library
Bunch Length Measurements With Laser/SR Cross-Correlation (open access)

Bunch Length Measurements With Laser/SR Cross-Correlation

By operating SPEAR3 in low-{alpha} mode the storage ring can generate synchrotron radiation pulses of order 1ps. Applications include pump-probe x-ray science and the production of THz radiation in the CSR regime. Measurements of the bunch length are difficult, however, because the light intensity is low and streak cameras typically provide resolution of only a few ps. Tests are now underway to resolve the short bunch length using cross-correlation between a 60-fs Ti:Sapphire laser and the visible SR beam in a BBO crystal. In this paper we report on the experimental setup, preliminary measurements and prospects for further improvement.
Date: July 6, 2012
Creator: Miller, Timothy; Daranciang, Dan; Lindenberg, Aaron; Corbett, Jeff; Fisher, Alan; Goodfellow, John et al.
Object Type: Article
System: The UNT Digital Library
Controlling the Actuation Rate of Low Density Shape Memory Polymer Foams in Water (open access)

Controlling the Actuation Rate of Low Density Shape Memory Polymer Foams in Water

None
Date: July 6, 2012
Creator: Singhal, P.; Boyle, T.; Infanger, S.; Letts, S.; Small, W.; Maitland, D. J. et al.
Object Type: Article
System: The UNT Digital Library
Conventional Prompt Global Strike and Long-Range Ballistic Missiles: Background and Issues (open access)

Conventional Prompt Global Strike and Long-Range Ballistic Missiles: Background and Issues

Prompt global strike (PGS) would allow the United States to strike targets anywhere on Earth with conventional weapons in as little as an hour. This report looks at some concerns that Congress has shown for the PGS program, including the Department of Defenses' rationale for the mission, the Air Force's ability to set up the system in a timely manner, and how the new START Treaty between the US and Russia will affect the system.
Date: July 6, 2012
Creator: Woolf, Amy F.
Object Type: Report
System: The UNT Digital Library
CSR in the SuperKEKB Damping Ring (open access)

CSR in the SuperKEKB Damping Ring

Coherent synchrotron radiation (CSR) is generated when a bunched beam traverses a dipole magnet or a wiggler/undulator. It can degrade the beam quality in both storage rings and linacs through enhancing the beam energy spread and lengthening the bunch length, even cause single-bunch microwave instabilities. Using several methods, CSR impedances in the positron damping ring (DR) of the SuperKEKB which is under design were calculated. From the impedances due to CSR, resistive wall and various vacuum components, quasi-Green function wake potentials were constructed and used in simulations of Particle-In-Cell (PIC) tracking. We present the CSR related results in this paper.
Date: July 6, 2012
Creator: Zhou, Demin; Abe, Tetsuo; Ikeda, Hitomi; Kikuchi, Mitsuo; Ohmi, Kazuhito; Oide, Katsunobu et al.
Object Type: Article
System: The UNT Digital Library
Design of Accelerator Online Simulator Server Using Structured Data (open access)

Design of Accelerator Online Simulator Server Using Structured Data

Model based control plays an important role for a modern accelerator during beam commissioning, beam study, and even daily operation. With a realistic model, beam behaviour can be predicted and therefore effectively controlled. The approach used by most current high level application environments is to use a built-in simulation engine and feed a realistic model into that simulation engine. Instead of this traditional monolithic structure, a new approach using a client-server architecture is under development. An on-line simulator server is accessed via network accessible structured data. With this approach, a user can easily access multiple simulation codes. This paper describes the design, implementation, and current status of PVData, which defines the structured data, and PVAccess, which provides network access to the structured data.
Date: July 6, 2012
Creator: Shen, Guobao; /Brookhaven; Chu, Chungming; /SLAC; Wu, Juhao; /SLAC et al.
Object Type: Article
System: The UNT Digital Library
Drug Control: Initial Review of the National Strategy and Drug Abuse Prevention and Treatment Programs (open access)

Drug Control: Initial Review of the National Strategy and Drug Abuse Prevention and Treatment Programs

Correspondence issued by the Government Accountability Office with an abstract that begins "To implement the 2010 National Drug Control Strategy, ONDCP obtained input from drug control stakeholders to help ensure that they shared responsibility for implementation, established a new process to determine progress made, and reported that most action items in the Strategy were on track or complete as of November 2011. ONDCP officials stated that they developed the 2010 Strategy’s seven objectives—for example, Strengthen Efforts to Prevent Drug Use in Our Communities—and 106 action items under these objectives through a consultative process with federal, state, and local drug control agencies and other stakeholders. Officials from the four agencies we spoke with as of April 2012 stated that ONDCP sought input from them to develop the Strategy and that as a result, existing agency priorities and activities are reflected in the Strategy. ONDCP officials stated that this alignment helps facilitate Strategy implementation. In August 2010, ONDCP initiated a process to track progress made on Strategy action items. As part of this process, ONDCP requested that each agency develop and submit (1) a plan for implementing each action item for which it has lead responsibility and (2) status updates on implementation …
Date: July 6, 2012
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Electron Cloud at Low Emittance in CesrTA (open access)

Electron Cloud at Low Emittance in CesrTA

The Cornell Electron Storage Ring (CESR) has been reconfigured as a test accelerator (CesrTA) for a program of electron cloud (EC) research at ultra low emittance. The instrumentation in the ring has been upgraded with local diagnostics for measurement of cloud density and with improved beam diagnostics for the characterization of both the low emittance performance and the beam dynamics of high intensity bunch trains interacting with the cloud. A range of EC mitigation methods have been deployed and tested and their effectiveness is discussed. Measurements of the electron cloud's effect on the beam under a range of conditions are discussed along with the simulations being used to quantitatively understand these results.
Date: July 6, 2012
Creator: Palmer, Mark; /Cornell U., CLASSE; Alexander, James; /Cornell U., CLASSE; Billing, Michael; /Cornell U., CLASSE et al.
Object Type: Article
System: The UNT Digital Library
Ensemble Single Column Modeling in the Tropics - Derivation of observed forcing data sets, estimation of observation uncertainty and application to parametrization improvements (open access)

Ensemble Single Column Modeling in the Tropics - Derivation of observed forcing data sets, estimation of observation uncertainty and application to parametrization improvements

The project was carried out in 2 distinct phases. In the first phase we established the general validity of using an ensemble approach to Single Column Modeling (SCM) using the Manus and Nauru sites. In the second phase we derived and applied an ensemble forcing derivation technique to observations. First we derived an ensemble forcing estimate for the TWP-ICE experiment and then by extended the method to provide three wet seasons of “continuous ensemble forcing” for the Darwin site. The main purpose of using ensemble techniques in SCM simulation is to be able to assess how much of the overall SCM simulation error is due to model errors and how much due to errors in the forcing.
Date: July 6, 2012
Creator: Jakob, Christian
Object Type: Report
System: The UNT Digital Library
Federal Agency Actions Following the Supreme Court’s Climate Change Decision in Massachusetts v. EPA: A Chronology (open access)

Federal Agency Actions Following the Supreme Court’s Climate Change Decision in Massachusetts v. EPA: A Chronology

This report provides a Chronology on Federal Agency Actions Following the Supreme Court’s Climate Change Decision in Massachusetts v. EPA.This report provides action mainly by EPA that involve climate change.
Date: July 6, 2012
Creator: Meltz, Robert
Object Type: Report
System: The UNT Digital Library
Federal Assistance for Wildfire Response and Recovery (open access)

Federal Assistance for Wildfire Response and Recovery

This report briefly discusses the options for federal support and assistance for areas affected by wildfire disaster including the period during wildfires, in the aftermath, and later for preventing a recurrence.
Date: July 6, 2012
Creator: Bracmort, Kelsi
Object Type: Report
System: The UNT Digital Library
Feedback Requirements for SASE-FELs (open access)

Feedback Requirements for SASE-FELs

The operation of a Self Amplified Spontaneous Emission (SASE) Free Electron Lasers (FEL) at soft and hard X-ray wavelengths driven by a high brightness electron beam imposes strong requirements on the stability of the accelerator and feedback systems are necessary to both guarantee saturation of the SASE process as well as a stable photon beam for user experiments. Diagnostics for the relevant transverse and longitudinal beam parameters are presented and various examples of feedback systems for bunches with low repetition rate as well as systems for intra bunch train feedbacks are discussed.
Date: July 6, 2012
Creator: Loos, Henrik
Object Type: Article
System: The UNT Digital Library
First Operation of the Abort Gap Monitor for LHC (open access)

First Operation of the Abort Gap Monitor for LHC

The Large Hadron Collider (LHC) beam-dump system relies on extraction kickers that need 3 microseconds to rise to their nominal field. Since particles transiting the kickers during the rise will not be dumped properly, the proton population in this interval must always remain below quench and damage limits. A specific monitor to measure the particle population of this gap has been designed based on the detection of synchrotron radiation using a gated photomultiplier. Since the quench and damage limits change with the beam energy, the acceptable population in the abort gap and the settings of the monitor must adapt accordingly. This paper presents the design of the monitor, the calibration procedure and the detector performance with beam.
Date: July 6, 2012
Creator: Lefevre, Thibaut; Bart Pedersen, Stephane; Boccardi, Andrea; Bravin, Enrico; Goldblatt, A.; Jeff, Adam et al.
Object Type: Article
System: The UNT Digital Library
Identifying Longitudinal Jitter Sources in the LCLS Linac (open access)

Identifying Longitudinal Jitter Sources in the LCLS Linac

The Linac Coherent Light Source (LCLS) at SLAC is an x-ray Free Electron Laser (FEL) with wavelengths of 0.15 nm to 1.5 nm. The electron beam stability is important for good lasing. While the transverse jitter of the beam is about 10-20% of the rms beam sizes, the jitter in the longitudinal phase space is a multiple of the energy spread and bunch length. At the lower energy of 4.3 GeV (corresponding to the longest wavelength of 1.5 nm) the relative energy jitter can be 0.125%, while the rms energy spread is with 0.025% five times smaller. An even bigger ratio exists for the arrival time jitter of 50 fs and the bunch duration of about 5 fs (rms) in the low charge (20 pC) operating mode. Although the impact to the experiments is reduced by providing pulse-by-pulse data of the measured energy and arrival time, it would be nice to understand and mitigate the root causes of this jitter. The thyratron of the high power supply of the RF klystrons is one of the main contributors. Another suspect is the multi-pacting in the RF loads. Phase measurements down to 0.01 degree (equals 10 fs) along the RF pulse were …
Date: July 6, 2012
Creator: Decker, Franz-Josef; Akre, Ron; Brachmann, Axel; Craft, Jim; Ding, Yuantao; Dowell, David et al.
Object Type: Article
System: The UNT Digital Library
LLRF System Upgrade for the SLAC Linac (open access)

LLRF System Upgrade for the SLAC Linac

The Linac Coherent Light Source (LCLS) at SLAC is in full user operation and has met the stability goals for stable lasing. The 250pC bunch can be compressed to below 100fS before passing through an undulator. In a new mode of operation a 20pC bunch is compressed to about 10fS. Experimenters are regularly using this shorter X-ray pulse and getting pristine data. The 10fS bunch has timing jitter on the order of 100fS. Physicists are requesting that the RF system achieve better stability to reduce timing jitter. Drifts in the RF system require longitudinal feedbacks to work over large ranges and errors result in reduced performance of the LCLS. A new RF system is being designed to help diagnose and reduce jitter and drift in the SLAC linac.
Date: July 6, 2012
Creator: Hong, Bo; Akre, Ron & Pacak, Vojtech
Object Type: Article
System: The UNT Digital Library
Low Emittance Tuning Studies for SuperB (open access)

Low Emittance Tuning Studies for SuperB

SuperB[1] is an international project for an asymmetric 2 rings collider at the B mesons cm energy to be built in the Rome area in Italy. The two rings will have very small beam sizes at the Interaction Point and very small emittances, similar to the Linear Collider Damping Rings ones. In particular, the ultra low vertical emittances, 7 pm in the LER and 4 pm in the HER, need a careful study of the misalignment errors effects on the machine performances. Studies on the closed orbit, vertical dispersion and coupling corrections have been carried out in order to specify the maximum allowed errors and to provide a procedure for emittance tuning. A new tool which combines MADX and Matlab routines has been developed, allowing for both corrections and tuning. Results of these studies are presented.
Date: July 6, 2012
Creator: Liuzzo, Simone; /INFN, Pisa; Biagini, Maria; /INFN, Rome; Raimondi, Pantaleo; /INFN, Rome et al.
Object Type: Article
System: The UNT Digital Library
Managing Aging Effects on Dry Cask Storage Systems for Extended Long-Term Storage and Transportation of Used Fuel - Rev. 0 (open access)

Managing Aging Effects on Dry Cask Storage Systems for Extended Long-Term Storage and Transportation of Used Fuel - Rev. 0

The cancellation of the Yucca Mountain repository program in the United States raises the prospect of extended long-term storage (i.e., >120 years) and deferred transportation of used fuel at operating and decommissioned nuclear power plant sites. Under U.S. federal regulations contained in Title 10 of the Code of Federal Regulations (CFR) 72.42, the initial license term for an Independent Spent Fuel Storage Installation (ISFSI) must not exceed 40 years from the date of issuance. Licenses may be renewed by the U.S. Nuclear Regulatory Commission (NRC) at the expiration of the license term upon application by the licensee for a period not to exceed 40 years. Application for ISFSI license renewals must include the following: (1) Time-limited aging analyses (TLAAs) that demonstrate that structures, systems, and components (SSCs) important to safety will continue to perform their intended function for the requested period of extended operation; and (2) a description of the aging management program (AMP) for management of issues associated with aging that could adversely affect SSCs important to safety. In addition, the application must also include design bases information as documented in the most recent updated final safety analysis report as required by 10 CFR 72.70. Information contained in previous …
Date: July 6, 2012
Creator: Chopra, O. K.; Diercks, D.; Fabian, R.; Ma, D.; Shah, V.; Tam, S. W. et al.
Object Type: Report
System: The UNT Digital Library

Midwestern State University Historically Underutilized Business Strategic Plan: [2013]

Strategic plan for Midwestern State University outlining goals, objectives, measures, and other information about working with Historically Underutilized Businesses (HUBs) during fiscal year 2013.
Date: July 6, 2012
Creator: Midwestern State University (Wichita Falls, Tex.)
Object Type: Musical Score/Notation
System: The Portal to Texas History
Monetary Policy and the Federal Reserve: Current Policy and Conditions (open access)

Monetary Policy and the Federal Reserve: Current Policy and Conditions

This report discusses how the Federal Reserve (Fed) handles monetary policy, including background information about the execution of monetary policy, the recent and current stance of monetary policy, and current legislation and Congressional oversight that would affect the Fed's practices.
Date: July 6, 2012
Creator: Labonte, Marc
Object Type: Report
System: The UNT Digital Library
Monetary Policy and the Federal Reserve: Current Policy and Conditions (open access)

Monetary Policy and the Federal Reserve: Current Policy and Conditions

This report discusses economic effects of the Federal Reserve's monetary policy, monetary policy vs. fiscal policy, the current stance of monetary policy given the financial crisis, and Congressional oversight and disclosure on the issue.
Date: July 6, 2012
Creator: Labonte, Marc
Object Type: Report
System: The UNT Digital Library
A New Interaction Region Design for the Super-B Factory (open access)

A New Interaction Region Design for the Super-B Factory

A final focus magnet design that uses super-ferric magnets is introduced for the SuperB interaction region. The baseline design has air-core super-conducting quadrupoles. This idea instead uses super-conducting wire in an iron yoke. The iron is in the shape of a Panofsky quadrupole and this allows two quadrupoles to be side-by-side with no intervening iron as long as the gradients of the two quads are equal. This feature allows us to move in as close as possible to the collision point and minimize the beta functions in the interaction region. The superferric design has advantages as well as drawbacks and we will discuss these in the paper.
Date: July 6, 2012
Creator: Sullivan, Michael; Bertsche, Kirk; Bettoni, Simona; Paoloni, Eugenio; Raimondi, Pantaleo & Vobly, Pavel
Object Type: Article
System: The UNT Digital Library
Nucleation and Precipitation Processes in the Vadose Zone during Contaminant Transport: Final Technical Report (open access)

Nucleation and Precipitation Processes in the Vadose Zone during Contaminant Transport: Final Technical Report

The report describes results of experiments to synthesize and characterize uranium(VI)-silicates from solutions containing dissolved U(VI), Si, Na, and nitrate as a function of solution pH and Si:U ratio under ambient conditions. Solids characterization was accomplished by X-ray diffraction, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and high-energy X-ray scattering (HEXS) analysis. The purpose was to develop a framework for describing the formation of U(VI)-silicate solids that might form in contaminated soils and sediments under oxidizing conditions in the presence of aqueous uranium, and are known to exist naturally in geologic uranium deposits.
Date: July 6, 2012
Creator: Nagy, Kathryn L.
Object Type: Report
System: The UNT Digital Library
Operational Experiences Tuning the ATF2 Final Focus Optics Towards Obtaining a 37nm Electron Beam IP Spot Size (open access)

Operational Experiences Tuning the ATF2 Final Focus Optics Towards Obtaining a 37nm Electron Beam IP Spot Size

The primary aim of the ATF2 research accelerator is to test a scaled version of the final focus optics planned for use in next-generation linear lepton colliders. ATF2 consists of a 1.3 GeV linac, damping ring providing low-emittance electron beams (< 12pm in the vertical plane), extraction line and final focus optics. The design details of the final focus optics and implementation at ATF2 are presented elsewhere. The ATF2 accelerator is currently being commissioned, with a staged approach to achieving the design IP spot size. It is expected that as we implement more demanding optics and reduce the vertical beta function at the IP, the tuning becomes more difficult and takes longer. We present here a description of the implementation of the tuning procedures and describe operational experiences and performances.
Date: July 6, 2012
Creator: White, Glen; Seryi, Andrei; Woodley, Mark; Bai, Sha; Bambade, Philip; Renier, Yves et al.
Object Type: Article
System: The UNT Digital Library
Optimization of the CLIC Baseline Collimation System (open access)

Optimization of the CLIC Baseline Collimation System

Important efforts have recently been dedicated to the improvement of the design of the baseline collimation system of the Compact Linear Collider (CLIC). Different aspects of the design have been optimized: the transverse collimation depths have been recalculated in order to reduce the collimator wakefield effects while maintaining a good efficiency in cleaning the undesired beam halo; the geometric design of the spoilers have also been reviewed to minimize wakefields; in addition, the optics design have been polished to improve the collimation efficiency. This paper describes the current status of the CLIC collimation system after this optimization.
Date: July 6, 2012
Creator: Resta-Lopez, Javier; /Oxford U., JAI; Angal-Kalinin, Deepa; /Daresbury; Fernandez-Hernando, Juan; /Daresbury et al.
Object Type: Article
System: The UNT Digital Library