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Coherent Electromagnetic Effects in High-Current Particle Accelerators: [Part] 3. Electromagnetic-Coupling Instabilities in a Coasting Beam

Description: The electromagnetic interaction of an intense relativistic coasting beam with itself, including the effect of a confining nonperfect vacuum tank, or a quiescent rf cavity, is investigated theoretically. It is shown that the resonances that may occur between harmonics of the particle circulation frequencies and the electromagnetic modes of the cavities can lead to a longitudinal instability of the beam. A criterion for stability of the beam against such longitudinal bunching is obtained as a res… more
Date: August 4, 1960
Creator: Laslett, L. J.; Neil, V. Kelvin & Sessler, A. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Quench Protection for the MICE Cooling Channel Coupling Magnet

Description: This paper describes the passive quench protection system selected for the muon ionization cooling experiment (MICE) cooling channel coupling magnet. The MICE coupling magnet will employ two methods of quench protection simultaneously. The most important method of quench protection in the coupling magnet is the subdivision of the coil. Cold diodes and resistors are put across the subdivisions to reduce both the voltage to ground and the hot-spot temperature. The second method of quench protecti… more
Date: August 2, 2008
Creator: Guo, Xing Long; Xu, Feng Yu; Wang, Li; Green, Michael A.; Pan, Heng; Wu, Hong et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Flux analysis of central metabolic pathways in the Fe(III)-reducing organism Geobacter metallireducens via 13C isotopiclabeling

Description: We analyzed the carbon fluxes in the central metabolism ofGeobacter metallireducens strain GS-15 using 13C isotopomer modeling.Acetate labeled in the 1st or 2nd position was the sole carbon source,and Fe-NTA was the sole terminal electron acceptor. The measured labeledacetate uptake rate was 21 mmol/gdw/h in the exponential growth phase.The resulting isotope labeling pattern of amino acids allowed an accuratedetermination of the in vivo global metabolic reaction rates (fluxes)through the centra… more
Date: August 13, 2007
Creator: Tang, Yinjie J.; Chakraborty, Romy; Martin, Hector Garcia; Chu,Jeannie; Hazen, Terry C. & Keasling, Jay D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Analysis of the Cause of High External Q Modes in the JLab High Gradient Prototype Cryomodule Renascence

Description: The Renascence cryomodule [1] installed in CEBAF in 2007 consists of 8 cavities as shown in Figure 1. The first three cavities (No.1-No.3) in the upstream end are of the Low Loss (LL) shape design, and the remaining 5 cavities (No.4-No.8) on the beam downstream end are the High Gradient (HG) shape design. The fundamental power couplers (FPCs) are the rectangular waveguides, and the little cylindrical structures are the HOM couplers. The locations of the FPC in the last four cavities are mirrore… more
Date: June 27, 2008
Creator: Li, Z.; Akcelik, V.; Xiao, L.; Lee, L.; Ng, C.; Ko, K. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

COHERENT ELECTROMAGNETIC EFFECTS IN HIGH-CURRENT PARTICLE ACCELERATORS: I. INTERACTION OF A PARTICLE BEAM WITH AN EXTERNALLY DRIVEN RADIO-FREQUENCY CAVITY

Description: A calculation is made of the interaction of a beam of particles in an accelerator with the radio-frequency cavity that provides the accelerating mechanism of the machine. A Hamiltonian for synchrotron motion is employed that makes possible the simultaneous solution of Maxwell's equations and the Vlasov equation, so that a self-consistent distribution of particles in synchrotron phase space is determined. The effective voltage on the cavity due to the beam of charged particles is of the order of… more
Date: July 1, 1960
Creator: Neil, V. Kelvin & Sessler, Andrew M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

X-Band Traveling Wave Rf Deflector Structures

Description: Design studies on the X-Band transverse RF deflectors operating at HEM{sub ll} mode have been made for two different applications. One is for beam measurement of time-sliced emittance and slice energy spread for the upgraded LCLS project, its optimization in RF efficiency and system design are carefully considered. Another is to design an ultra-fast RF kicker in order to pick up single bunches from the bunch-train of the B-factory storage ring. The challenges are to obtain very short structure … more
Date: December 18, 2008
Creator: Wang, J. W. & Tantawi, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Preliminary Analysis of the Economics of Using Distributed Energy as a Source of Reactive Power Supply

Description: A major blackout affecting 50 million people in the Northeast United States, where insufficient reactive power supply was an issue, and an increased number of filings made to the Federal Energy Regulatory Commission by generators for reactive power has led to a closer look at reactive power supply and compensation. The Northeastern Massachusetts region is one such area where there is an insufficiency in reactive power compensation. Distributed energy due to its close proximity to loads seems to… more
Date: April 1, 2006
Creator: Li, Fangxing; Kueck, John D; Rizy, D Tom & King, Thomas F
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Impedance calculation for ferrite inserts

Description: Passive ferrite inserts were used to compensate the space charge impedance in high intensity space charge dominated accelerators. They study the narrowband longitudinal impedance of these ferrite inserts. they find that the shunt impedance and the quality factor for ferrite inserts are inversely proportional to the imaginary part of the permeability of ferrite materials. They also provide a recipe for attaining a truly passive space charge impedance compensation and avoiding narrowband microwav… more
Date: January 1, 2005
Creator: Breitzmann, S. C.; Lee, S. Y. & Ng, K. Y.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

STRIPLINE KICKER DESIGN FOR NSLS2 STORAGE RING

Description: In the NSLS2 storage ring, there are four stripline kickers/pickups. Two long striplines with electrode length of 30cm will be used as bunch-by-bunch transverse feedback actuators. Two short stripline kickers/pickups with 15cm length will mainly used for tune measurement excitation or signal pickup for the beam stability monitor. High shunt impedance of the long stripline kickers is demanded to produce 200 {micro}s damping time. Meanwhile the beam impedance should be minimized. The design work … more
Date: March 28, 2011
Creator: Cheng, W.; Blednykh, A.; Krinsky, S. & Singh, O.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Options for an 11 GeV RF Beam Separator for the Jefferson Lab CEBAF Upgrade

Description: The CEBAF accelerator at Jefferson Lab has had, since first demonstration in 1996, the ability to deliver a 5-pass electron beam to experimental halls (A, B, and C) simultaneously. This capability was provided by a set of three, room temperature 499 MHz rf separators in the 5th pass beamline. The separator was two-rod, TEM mode type resonator, which has a high shunt impedance. The maximum rf power to deflect the 6 GeV beams was about 3.4kW. The 12 GeV baseline design does not preserve the capab… more
Date: May 1, 2009
Creator: Jean Delayen, Michael Spata, Haipeng Wang
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.

Description: Arc faults in photovoltaic (PV) modules have caused multiple rooftop fires. The arc generates a high-temperature plasma that ignites surrounding materials and subsequently spreads the fire to the building structure. While there are many possible locations in PV systems and PV modules where arcs could initiate, bypass diodes have been suspected of triggering arc faults in some modules. In order to understand the electrical and thermal phenomena associated with these events, a finite element mode… more
Date: January 1, 2012
Creator: Bower, Ward Isaac; Quintana, Michael A. & Johnson, Jay
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Quench anaylsis of MICE spectrometer superconducting solenoid

Description: MICE superconducting spectrometer solenoids fabrication and tests are in progress now. First tests of the Spectrometer Solenoid discovered some issues which could be related to the chosen passive quench protection system. Both solenoids do not have heaters and quench propagation relied on the 'quench back' effect, cold diodes, and shunt resistors. The solenoids have very large inductances and stored energy which is 100% dissipated in the cold mass during a quench. This makes their protection a … more
Date: September 1, 2011
Creator: Kashikhin, Vladimir; Bross, Alan & Prestemon, Soren
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Precision, 32 Channel Power Supply System

Description: A modular, multichannel current regulator system has been developed to power the low current correction and focusing magnets used for beam transport. The basic module consists of a relay rack housing four card crates with eight regulators per crate. The rack also contains a utility chassis and common power supplies. Each regulator card includes a communications microprocessor and a temperature controlled analog circuit block containing precision reference, serial DAC, shunt resistor and error a… more
Date: September 1, 1990
Creator: Boettcher, E.; La Mora, B.; O'Sullivan, Michael; Dobeck, Nicholas; Francis, Peter; Beaufait, Joseph et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nanowire-based All Oxide Solar Cells

Description: We present an all-oxide solar cell fabricated from vertically oriented zinc oxide nanowires and cuprous oxide nanoparticles. Our solar cell consists of vertically oriented n-type zinc oxide nanowires, surrounded by a film constructed from p-type cuprous oxide nanoparticles. Our solution-based synthesis of inexpensive and environmentally benign oxide materials in a solar cell would allow for the facile production of large-scale photovoltaic devices. We found that the solar cell performance is en… more
Date: December 7, 2008
Creator: Yang*, Benjamin D. Yuhas and Peidong & Yang, Peidong
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Passive modal damping with piezoelectric shunts

Description: The use of piezoelectric materials in conjunction with passive inductance-resistance-capacitance (RLC) circuits to dampen specific vibration modes is explored. The piezoelectric materials convert mechanical energy to electrical energy, which is then dissipated in the RLC circuit through joule heating. An impulse is applied to a simple cantilevered beam and by varying the inductance and resistance values, the natural oscillation frequency fcir the RLC circuit is tuned to dampen the first mode of… more
Date: January 1, 2001
Creator: Granier, J. J. (John J.); Haundhausen, R. J. (R. Jason) & Gaytan, G. E. (Gabriel E.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Comparative Genomics of Regulation of Fatty Acid and Branched-chain Amino Acid Utilization in Proteobacteria

Description: Bacteria can use branched-chain amino acids (ILV, i.e. isoleucine, leucine, valine) and fatty acids (FA) as sole carbon and energy sources convering ILV into acetyl-CoA, propanoyl-CoA and propionyl-CoA, respectively. In this work, we used the comparative genomic approach to identify candidate transcriptional factors and DNA motifs that control ILV and FA utilization pathways in proteobacteria. The metabolic regulons were characterized based on the identification and comparison of candidate tran… more
Date: October 31, 2008
Creator: Kazakov, Alexey E.; Rodionov, Dmitry A.; Arkin, Adam Paul; Dubchak, Inna; Gelfand, Mikhail S. & Alm, Eric
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

High Power, High Voltage FETs in Linear Applications: A User's Perspective

Description: The specifications of the current crop of highpower, high-voltage field-effect transistors (FETs) can lure a designer into employing them in high-voltage DC equipment. Devices with extremely low on-resistance and very high power ratings are available from several manufacturers. However, our experience shows that high-voltage, linear operation of these devices at near-continuous duty can present difficult reliability challenges at stress levels well-below their published specifications. This pap… more
Date: September 21, 2009
Creator: Greenough, N.; Fredd, E. & DePasquale, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Experiments on HOM spectrum manipulation in a 1.3 GHz ILC SC cavity

Description: Superconducting cavities with high operating Q will be installed in the Project-X, a superconducting linac, which is under development at Fermilab. Possibility of cavity design without HOM couplers considered. Rich spectrum of the beam and large number of cavities in ProjectX linac can result to resonance excitation of some high order modes with high shunt impedance. Under scope of study of High order modes damping the manipulation with HOM spectrum in cold linac is considered. Results of detun… more
Date: March 1, 2011
Creator: Khabiboulline, T.; Solyak, N.; Yakovlev, V. & /Fermilab
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Wakefield Effects of Pulsed Crab Cavities at the Advanced Photon Source for Short-X-ray Pulse Generation

Description: In recent years we have explored the application to the Advanced Photon Source (APS) of Zholents' crab-cavity based scheme for production of short x-ray pulses. As a near-term project, the APS has elected to pursue a pulsed system using room-temperature cavities. The cavity design has been optimized to heavily damp parasitic modes while maintaining large shunt impedance for the deflecting dipole mode. We evaluated a system consisting of three crab cavities as an impedance source and determined … more
Date: November 7, 2007
Creator: Chae, Y. -C.; Waldschmidt, G. & Dolgashev, V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Premliminary Report on Strength of 1/2 of a 3Q120

Description: Attached please find some data taken on the dates show at MTF on a 3Q12OA magnet by utilizing a Morgan Coil for determining the strength of the quadrupole component. The probe was inserted approximately 1/2 the distance through the magnet (accuracy of longitudinal placement about .25 inch) and was rotated to record the flux change at constant current. The data are listed twice: once in time order and once sorted by current. It should be noted that these measurements were begun when the magnet h… more
Date: April 12, 1985
Creator: Brown, B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Study on the Humidity Susceptibility of Thin-Film CIGS Absorber

Description: The report summarizes the research on the susceptibility of a thermally co-evaporated CuInGaSe2 (CIGS) thin-film absorber to humidity and its consequence on composition, morphology, electrical and electronic properties, and device efficiency.
Date: January 1, 2010
Creator: Pern, F. J.; Egaas, B.; To, B.; Jiang, C. S.; Li, J. V.; Glynn, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Detecting and Blocking Network Attacks at Ultra High Speeds

Description: Stateful, in-depth, in-line traffic analysis for intrusion detection and prevention has grown increasingly more difficult as the data rates of modern networks rise. One point in the design space for high-performance network analysis - pursued by a number of commercial products - is the use of sophisticated custom hardware. For very high-speed processing, such systems often cast the entire analysis process in ASICs. This project pursued a different architectural approach, which we term Shunting.… more
Date: November 29, 2010
Creator: Paxson, Vern
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

CIGS P1, P2, P3 Scribing Processes using a Pulse Programmable Industrial Fiber Laser: Preprint

Description: We describe a novel set of laser processes for the CIGS P1, P2 and P3 scribing steps, the development of which has been enabled by a unique pulse-programmable fiber laser. We find that the unique pulse control properties of this 1064 nm wavelength laser have significant effects on the material removal dynamics of the various film layers in the CIGS material system. In the case of the P2 and P3 processes, the shaped pulses create new laser/material interaction effects that permit the material to… more
Date: October 1, 2010
Creator: Rekow, M.; Murison, R.; Panarello, T.; Dunsky, C.; Dinkel, C.; Nikumb, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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