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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

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

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

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

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

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

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
open access

Test-to-Failure of Crystalline Silicon Modules: Preprint

Description: Accelerated lifetime testing of five crystalline silicon module designs was carried out according to the Terrestrial Photovoltaic Module Accelerated Test-to-Failure Protocol. This protocol compares the reliability of various module constructions on a quantitative basis. The modules under test are subdivided into three accelerated lifetime testing paths: 85..deg..C/85% relative humidity with system bias, thermal cycling between ?40..deg..C and 85..deg..C, and a path that alternates between damp … more
Date: October 1, 2010
Creator: Hacke, P.; Terwilliger, K.; Glick, S.; Trudell, D.; Bosco, N.; Johnston, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Module Design, Materials, and Packaging Research Team: Activities and Capabilities

Description: Our team activities are directed at improving PV module reliability by incorporating new, more effective, and less expensive packaging materials and techniques. New and existing materials or designs are evaluated before and during accelerated environmental exposure for the following properties: (1) Adhesion and cohesion: peel strength and lap shear. (2) Electrical conductivity: surface, bulk, interface and transients. (3) Water vapor transmission: solubility and diffusivity. (4) Accelerated wea… more
Date: January 1, 2005
Creator: McMahon, T. J.; del Cueto, J.; Glick, S.; Jorgensen, G.; Kempe, M.; Kennedy, C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Analysis of a grid window structure for RF cavities in a Muon cooling channel

Description: We report on the electromagnetic and thermal analysis of a grid window structure for high gradient, low frequency RF cavities. Windows may be utilized to close the beam iris and increase shunt impedance of closed-cell RF cavities. This work complements previous work presented for windows made of solid beryllium foil. An electromagnetic and thermal analysis of the thin wall tubes in a grid pattern was conducted using both MAFIA4 and ANSYS finite element analyses. The results from both codes agre… more
Date: May 1, 2003
Creator: Ladran, A.; Li, D.; Moretti, A.; Rimmer, R.; Staples, J.; Virostek, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A 201 MHz RF cavity design with non-stressed pre-curved Be windows for muon cooling channels

Description: We present a 201-MHz RF cavity design for muon cooling channels with non-stressed and pre-curved Be foils to terminate the beam apertures. The Be foils are necessary to improve the cavity shunt impedance with large beam apertures needed for accommodating large transverse size muon beams. Be is a low-Z material with good electrical and thermal properties. It presents an almost transparent window to muon beams, but terminates the RF cavity electro-magnetically. Previous designs use pre-stressed f… more
Date: May 1, 2003
Creator: Li, Derun; Ladran, A.; Staples, J.; Virostek, S.; Zisman, M.; Lau, W. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Excess Dark Currents and Transients in Thin-Film CdTe Solar Cells: Implications for Cell Stability and Encapsulation of Scribe Lines and Cell Ends in Modules

Description: We have isolated a non-linear, metastable, shunt-path failure mechanism located at the CdS/CdTe cell edge. In such cases, most performance loss, usually erratic, can be associated with the shunt path. We studied these shunt paths using dark current-transients and infrared (ir) imaging and find only one shunt path per cell and only at the cell corner wall, even in badly degraded cells. The effect on diminishing the cell's efficiency far exceeds what would be expected from the cell's linear shunt… more
Date: February 1, 2005
Creator: McMahon, T. J.; Berniard, T. J.; Albin, D. S. & Demtsu, S. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Design and Development of Superconducting Parallel-Bar Deflecting/Crabbing Cavities

Description: The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties that is being considered for a number of applications. We present the designs of a 499 MHz deflecting cavity developed for the Jefferson Lab 12 GeV Upgrade and a 400 MHz crabbing cavity for the LHC High Luminosity Upgrade. Prototypes of these two cavities are now under development and fabrication.
Date: July 1, 2012
Creator: Payagalage Subashini Uddi De Silva, Jean Delayen
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Use of 2nd and 3rd Level Correlation Analysis for Studying Degradation in Polycrystalline Thin-Film Solar Cells

Description: The correlation of stress-induced changes in the performance of laboratory-made CdTe solar cells with various 2nd and 3rd level metrics is discussed. The overall behavior of aggregated data showing how cell efficiency changes as a function of open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF) is explained using a two-diode, PSpice model in which degradation is simulated by systematically changing model parameters. FF shows the highest correlation with performa… more
Date: March 1, 2011
Creator: Albin, D. S.; del Cueto, J. A.; Demtsu, S. H. & Bansal, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The SPi chip as an integrated power management device for serial powering of future HEP experiments

Description: Serial powering is one viable and very efficient way to distribute power to future high energy physics (HEP) experiments. One promising way to realize serial powering is to have a power management device on the module level that provides the necessary voltage levels and features monitoring functionality. The SPi (Serial Powering Interface) chip is such a power manager and is designed to meet the requirements imposed by current SLHC upgrade plans. It incorporates a programmable shunt regulator, … more
Date: January 1, 2009
Creator: Trimpl, M.; Deptuch, G.; Gingu, C.; Yarema, R.; Holt, R.; Weber, M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nondestructive Performance Characterization Techniques for Module Reliability

Description: This paper describes nondestructive characterization techniques for module reliability. These techniques include light and dark current versus voltage and related analysis such as resistance, diode quality factor, and dark current. The use of the NREL laser scanner at zero volts and forward bias is also described as a technique to uncover cracks, shunts, and open-circuit regions in a module. Quantum-efficiency measurements of isolated cells or regions in a module are also possible. The interpre… more
Date: May 1, 2003
Creator: Emery, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Experiments Involving Correlations Between CdTe Solar Cell Fabrication History and Intrinsic Device Stability

Description: An orthogonal full-factorial design was used to study the effect of CdS and CdTe layer thickness, oxygen ambient during vapor CdCl2 (VCC) and the use of nitric-phosphoric (NP) acid as a pre-contact etch on the initial and stressed performance of CdS/CdTe small-area devices. The best initial device efficiency (using thinner CdS, thicker CdTe, no oxygen during VCC, and NP etch) also showed poor stability. Increasing the CdS thickness significantly improved stability with only a slight decrease in… more
Date: February 1, 2005
Creator: Albin, D.; McMahon, T.; Berniard, T.; Pankow, J.; Demtsu, S. & Noufi, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

SPi User Manual V0.1

Description: This document describes the Serial Powering Interface (SPi) ASIC. SPi is a general purpose ASIC prototype designed for use in serial powering of silicon detector instrumentation. This description is written as a user manual to aid application, not as a design description. SPi is a generic custom ASIC, manufactured in 0.25 {mu}m CMOS by TSMC, to interface between a constant current source and silicon detector read-out chips. There is no SEU (single event upset) protection, but most (not all) com… more
Date: May 1, 2011
Creator: Trimpl, M.; Yarema, R.; Newcomer, M.; Dressnandt, N.; Villani, G.; Weber, M. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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