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The Measurement of Lumped Parameter Impedance: A Metrology Guide

Description: Scope of the Guide: "This guide is not all-inclusive of the subject of impedance measurement and the reader should understand at the outset what he can or cannot expect to find. To help in establishing the bounds of subject matter included, consider the ideal impedance-measuring instrument as having the following the characteristics and capabilities: (1) unrestricted frequency range (2) unrestricted impedance range (3) unrestricted capabilities with respect to bias, ambience, applied power, etc. (4) error free (5) performs measurements instantaneously (6) zero acquisition cost (7) zero operating cost."
Date: June 1974
Creator: Jones, R. N. & Anson, W. J.
Partner: UNT Libraries Government Documents Department

An effective longitudinal space-charge impedance model for beamswith non-uniform and non-axissymmetric transverse density

Description: Use of a one-dimensional model of longitudinal space-charge(SC) impedance has been proposed for studying the microbunchinginstability in single-pass delivery systems relevant for the nextgeneration of FELs. For beams with uniform transverse density andcircular cross-section of radius r_b the SC impedance can be expressed ina handy analytical form, making this model particularly convenient. Inthis report we show how with an appropriate choice of r_b one can usethis as an effective-beam model to approximate beams with non-axissymmetric and non-uniform transverse densities.
Date: June 29, 2007
Creator: Venturini, Marco
Partner: UNT Libraries Government Documents Department

An improved statistical model for linear antenna input impedance in an electrically large cavity.

Description: This report presents a modification of a previous model for the statistical distribution of linear antenna impedance. With this modification a simple formula is determined which yields accurate results for all ratios of modal spectral width to spacing. It is shown that the reactance formula approaches the known unit Lorentzian in the lossless limit.
Date: March 1, 2005
Creator: Johnson, William Arthur; Warne, Larry Kevin; Jorgenson, Roy Eberhardt & Lee, Kelvin S. H. (ITT Industries/AES, Los Angeles, CA)
Partner: UNT Libraries Government Documents Department

Impedance Noise Identification for State-of-Health Prognostics

Description: Impedance Noise Identification is an in-situ method of measuring battery impedance as a function of frequency using a random small signal noise excitation source. Through a series of auto- and cross-correlations and Fast Fourier Transforms, the battery complex impedance as a function of frequency can be determined. The results are similar to those measured under a lab-scale electrochemical impedance spectroscopy measurement. The lab-scale measurements have been shown to correlate well with resistance and power data that are typically used to ascertain the remaining life of a battery. To this end, the Impedance Noise Identification system is designed to acquire the same type of data as an on-board tool. A prototype system is now under development, and results are being compared to standardized measurement techniques such as electrochemical impedance spectroscopy. A brief description of the Impedance Noise Identification hardware system and representative test results are presented.
Date: July 1, 2008
Creator: Christophersen, Jon P.; Motloch, Chester G.; Morrison, John L.; Donnellan, Ian B. & Morrison, William H.
Partner: UNT Libraries Government Documents Department

Impedance and Single Bunch Instability Calculations for the ILCDamping Ring

Description: An important action item for the damping rings of theInternational Linear Collider (ILC) is to compute the broad-bandimpedance and, from it, the threshold to the microwave instability. Wereport on the status of our study and provide a preliminary estimate ofthe instability threshold based on impedance models developed sofar.
Date: June 29, 2007
Creator: Venturini, Marco; Bane, Karl; Heifets, Sam; Li, Zhenhai; Ng, Cho; Novokhatski, Alexander et al.
Partner: UNT Libraries Government Documents Department

Reduced-volume antennas with integrated high-impedance electromagnetic surfaces.

Description: Several antennas with integrated high-impedance surfaces are presented. The high-impedance surface is implemented as a composite right/left-handed (CRLH) metamaterial fabricated from a periodic structure characterized by a substrate, filled with an array of vertical vias and capped by capacitive patches. Omnidirectional antennas placed in close proximity to the high-impedance surface radiate hemispherically with an increase in boresight far-field pattern gain of up to 10 dB and a front-to-back ratio as high as 13 dB at 2.45 GHz. Several TEM rectangular horn antennas are realized by replacing conductor walls with high-impedance surfaces. The TEM horn antennas are capable of operating below the TE{sub 1,0} cutoff frequency of a standard all-metal horn antenna, enabling a reduction in antenna volume. Above the cutoff frequency the TEM horn antennas function similarly to standard rectangular horn antennas.
Date: November 1, 2006
Creator: Forman, Michael A.
Partner: UNT Libraries Government Documents Department

THE COUPLING IMPEDANCE OF A TOROIDAL BEAM TUBE WITH CIRCULAR CROSS SECTION.

Description: IN THIS PAPER, THE LONGITUDINAL COUPLING IMPEDANCE OF A TOROIDAL BEAM TUBE WITH CIRCULAR CROSS SECION IS DERIVED IN THE FREQUENCY DOMAIN USING THE TOROIDAL COORDINATE SYSTEM. EXACT, ALTHOUGH COUPLED, DIFFERENTIAL EQUATIONS FOR THE AZIMUTHAL FIELD COMPONENTS ARE OBTAINED. AN APPROXIAMTE SOLUTION, VALID IN THE LIMIT OF SMALL CURVATURE, IS THEN DERIVED. ASSUMING EXTREME RELATIVISTIC ENERGIES AND A BEAM TUBE WITH PERFECTLY CONDUCTING WALLS, ONE FINDS A CLOSED-FORM EXPRESSION FOR THE PURELY REACTIVE COUPLING IMPEDANCE WHICH AT LOW MODE NUMBERS IS DEPENDENT ON THE TUBE GEOMETRY BUT WHICH AT VERY LARGE MODE NUMBERS APPROACHES THE FREE SPACE IMPEDANCE.
Date: March 29, 1999
Creator: HAHN,H.
Partner: UNT Libraries Government Documents Department

THE EQUILIBRIUM LENGTH OP HIGH-CURRENT BUNCHES IN ELECTRON STORAGE RINGS

Description: An equilibrium theory of the length of intense electron bunches circulating in a storage ring is presented. The consequence of electrical interaction with various resonant structures is expressed in terms of quadratures over the impedance of the structures, and impedance functions for a variety of elements are evaluated. It is shown that elements having resonances at high frequency can, above transition, cause bunches to increase in length with increasing current. The parametric dependence of the bunch lengthening is found to be in good agreement with observations, and numerical estimates, which are in substantial agreement with experiment, are presented.
Date: August 7, 1970
Creator: Pellegrini, C. & Sessler, A.M.
Partner: UNT Libraries Government Documents Department

High-Frequency Limit of Longitudinal Impedance

Description: A method of iterations which takes into account finite widths of resonances is developed and used to calculate the longitudinal impedance for a cylindrical cavity with side pipes. In the high-frequency limit the dependence of the real part of the impedance on the frequency is omega^(-1/2) in agreement with the estimate for the average impedance obtained by G. Do^me.
Date: August 1, 1987
Creator: Heifets, Sam & Heifets, Sam
Partner: UNT Libraries Government Documents Department

Transverse impedance localization using intensity dependent optics

Description: Measurements of transverse impedance in the SPS to track the evolution over the last few years show discrepancies compared to the analytical estimates of the major contributors. Recent measurements to localize the major sources of the transverse impedance using intensity dependent optics are presented. Some simulations using HEADTAIL to understand the limitations of the reconstruction and related numerical aspects are also discussed.
Date: May 4, 2009
Creator: Calaga,R.; Arduini, G.; Metral, E.; Papotti, G.; Quatraro, D.; Rumolo, G. et al.
Partner: UNT Libraries Government Documents Department

Comparison of Tevatron C0 and F0 Lambertson beam impedance

Description: Both the longitudinal and transverse beam impedance measurements for the Tevatron C0 and F0 lambertsons are presented. The C0 lambertsons were designed for circulating beam to travel through the 1 inch high by 6 inch wide field region. In the F0 lambertsons, circulating beam passes through the 2.5 inch high by 4 in ch wide field free region. The more recently designed F0 lambertsons have significantly less impedance than the older C0 lambertsons. Transverse impedance scales as one over the diameter of the aperture cubed. The three C0 style lambertsons were recently removed from the Tevatron. Four of the F0 lambertsons remain. Nine of the F0 style lambertsons are in the Main Injector and three more are required for Numi.
Date: April 11, 2003
Creator: Fellenz, James L Crisp and Brian
Partner: UNT Libraries Government Documents Department

Impedances and collective instabilities of the Tevatron at Run II

Description: The longitudinal and transverse coupling impedances of the Tevatron vacuum chamber are estimated and summed up. The resistive-wall impedances of the beam pipe and the laminations in the Lambertson magnets dominate below {approximately} 50 MHz. Then come the inductive parts of the bellows and BPM`s. The longitudinal and transverse collective instabilities, for both single bunch and multi bunches, are studied using Run II parameters. As expected the transverse coupled-bunch instability driven by the resistive-wall impedance is the most severe collective instability. However, it can be damped by a transverse damper designed for the correction of injection offsets. The power of such a damper has been studied.
Date: September 1, 1998
Creator: Ng, King-Yuen, FERMI
Partner: UNT Libraries Government Documents Department

Applying synchrotron phase measurement to the estimation of maximum beam intensity in the Fermilab Booster

Description: It is important to have experimental methods to estimate the maximum beam intensity for the Fermilab Booster as objective input into long term program commitments. An important existing limit is set by the available rf power. This limit is difficult to set a priori, because the real longitudinal impedance is not well known. The synchrotron phase at transition crossing was measured using both the mountain range plot and the direct phase measurement of the RF accelerating voltage relative to the beam, and results were consistent. They were applied to predict 6 x 10{sup 12} maximum Booster beam intensity with present running conditions.
Date: March 16, 2004
Creator: Yang, Xi & MacLachlan, James
Partner: UNT Libraries Government Documents Department

Analysis of formulas used in coupling impedance coaxial-wire measurements for distributed impedances

Description: In this paper we study the validity of coupling impedance bench measurements for distributed impedances, comparing the commonly used log formula to the result obtained applying a modified version of Bethe's theory of diffraction to a long slot in a coaxial beam pipe. The equations found provide a quantitative expression for the influence of the wire thickness used in the measurement of the real and imaginary part of the longitudinal impedance. The precision achievable in an actual measurement is therefore discussed. The method presented has also been applied in the presence of lumped impedances [1].
Date: May 30, 2002
Creator: De Santis, Stefano
Partner: UNT Libraries Government Documents Department

RHIC ABORT KICKER WITH REDUCED COUPLING IMPEDANCE.

Description: Kicker magnets typically represent the most important contributors to the transverse impedance budget of accelerators and storage rings. Methods of reducing the impedance value of the SNS extraction kicker presently under construction and, in view of a future performance upgrade, that of the RHIC abort kicker have been thoroughly studied at this laboratory. In this paper, the investigation of a potential improvement from using ferrite different from the BNL standard CMD5005 is reported. Permeability measurements of several ferrite types have been performed. Measurements on two kicker magnets using CMD5005 and C2050 suggest that the impedance of a magnet without external resistive damping, such as the RHIC abort kicker, would benefit.
Date: June 2, 2002
Creator: HAHN,H. & DAVINO,D.
Partner: UNT Libraries Government Documents Department

TRANSVERSE IMPEDANCE MEASUREMENT AT THE RHIC.

Description: The RHIC transverse impedance was measured during the last operation run. Measurement of the imaginary part of the broadband impedance was the main goal. No large difference between the two rings was found nor in either plane. The measured tune shift is larger than the expected by a factor of 2.5 to 3. Several other issues such as the real part impedance measurement are also presented.
Date: June 2, 2002
Creator: ZHANG,S.Y.; HUANG,H.; CAMERON,P.; DREES,A.; FLILLER,R. & SATOGATA,T.
Partner: UNT Libraries Government Documents Department

Fast Extraction Kicker for the Accelerator Test Facility

Description: We present the results of a study for the design of a fastextraction kicker to be installed in the Accelerator Test Facility ringat KEK. This activity is carried on in the framework of the ATF2 project,which will be built on the KEK Tsukuba campus as an extension of theexisting ATF, taking advantage of the world s smallest normalizedemittance achieved there. ATF2's primary goal is to operate as a testfacility and establish the hardware and beam handling technologiesenvisaged for the International Linear Collider. In particular, the fastextraction kicker object of the present paper is an important componentof the ILC damping rings, since its rise and fall time define the minimumdistance between bunches and ultimately the damping rings length itself.Building on the initial results presented at EPAC '06, we report on thepresent status of the kicker design and define the minimumcharacteristics for pulsers and other subsystems. In addition to theoriginal scheme with multiple stripline modules producing a totaldeflection of 5 mrad, we also investigated a scheme with a single kickermodule for a reduced deflection of 1 mrad placed inside a closed orbitbump, which takes the electron closer to the extractionseptum.
Date: June 20, 2007
Creator: De Santis, Stefano; Urakawa, Junji & Naito, Takashi
Partner: UNT Libraries Government Documents Department

AN ADVANCED CALIBRATION PROCEDURE FOR COMPLEX IMPEDANCE SPECTRUM MEASUREMENTS OF ADVANCED ENERGY STORAGE DEVICES

Description: With the increasing demand for electric and hybrid electric vehicles and the explosion in popularity of mobile and portable electronic devices such as laptops, cell phones, e-readers, tablet computers and the like, reliance on portable energy storage devices such as batteries has likewise increased. The concern for the availability of critical systems in turn drives the availability of battery systems and thus the need for accurate battery health monitoring has become paramount. Over the past decade the Idaho National Laboratory (INL), Montana Tech of the University of Montana (Tech), and Qualtech Systems, Inc. (QSI) have been developing the Smart Battery Status Monitor (SBSM), an integrated battery management system designed to monitor battery health, performance and degradation and use this knowledge for effective battery management and increased battery life. Key to the success of the SBSM is an in-situ impedance measurement system called the Impedance Measurement Box (IMB). One of the challenges encountered has been development of an accurate, simple, robust calibration process. This paper discusses the successful realization of this process.
Date: June 1, 2012
Creator: Morrison, William H.; Christophersen, Jon P.; Bald, Patrick & Morrison, John L.
Partner: UNT Libraries Government Documents Department

Rapid Impedance Spectrum Measurements for Onboard State-of-Health Applications

Description: Rapid impedance measurements can provide a useful online tool for improved state-of-health estimation. A validation study has been initiated at the Idaho National Laboratory for a rapid impedance technique known as Harmonic Compensated Synchronous Detection. This technique enables capturing the impedance spectra over a broad frequency range within about ten seconds. Commercially available lithium-ion cells are being calendar-life aged at 50°C with reference performance tests at 30°C every 32.5 days to gauge degradation The cells have completed the first set of reference performance tests and preliminary results are presented. The spectra change as a function of temperature and depth-of-discharge condition, as expected. The data indicate that the rapid impedance measurement technique is a benign measurement tool that can be successfully used to gauge changes in the corresponding pulse resistance.
Date: June 1, 2012
Creator: Christophersen, Jon P.; Morrison, John L. & Ho, Chinh D.
Partner: UNT Libraries Government Documents Department

Hardware Architecture for Measurements for 50-V Battery Modules

Description: Energy storage devices, especially batteries, have become critical for several industries including automotive, electric utilities, military and consumer electronics. With the increasing demand for electric and hybrid electric vehicles and the explosion in popularity of mobile and portable electronic devices such as laptops, cell phones, e-readers, tablet computers and the like, reliance on portable energy storage devices such as batteries has likewise increased. Because many of the systems these batteries integrated into are critical, there is an increased need for an accurate in-situ method of monitoring battery state-of-health. Over the past decade the Idaho National Laboratory (INL), Montana Tech of the University of Montana (Tech), and Qualtech Systems, Inc. (QSI) have been developing the Smart Battery Status Monitor (SBSM), an integrated battery management system designed to monitor battery health, performance and degradation and use this knowledge for effective battery management and increased battery life. Key to the success of the SBSM is an in-situ impedance measurement system called the Impedance Measurement Box (IMB). One of the challenges encountered has been development of a compact IMB system that will perform rapid accurate measurements of a battery impedance spectrum working with higher voltage batteries of up to 300 volts. This paper discusses the successful realization of a system that will work up to 50 volts.
Date: June 1, 2012
Creator: Bald, Patrick; Juras, Evan; Christophersen, Jon P. & Morrison, William
Partner: UNT Libraries Government Documents Department