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Frequency spectrum generated by AGS Booster power swing, heavy ion cycle

Description: LILCO is studying the effects of the AGS Booster power swing on its power grid. The study is being conducted by GE systems Development and Engineering, Schenectady, New York. In notes, dates November 10, 1987, prepared for a GE-LILCO Progress Review Meeting, the author notes LILCO system resonances that are excited by the heavy ion cycle. The data used by GE for their study, is the power flow required for continuous operation of the Booster, namely a continuous 13MW Power swing and a period of … more
Date: July 17, 1992
Creator: Meth, M. & Ratti, A.
Partner: UNT Libraries Government Documents Department
open access

Bunch-Length Measurements in PEP-II

Description: We measured the lengths of colliding e{sup +}e{sup -} bunches in the PEP-II B Factory at SLAC using various techniques. First, at several RF voltages and with both single-bunch and multibunch beams, a synchroscan streak camera measured synchrotron emission through a narrow blue filter. With 3.8 MV of RF, the length of a single positron bunch was 12 mm at low current, rising to 13 mm at 1.5 mA and 14.8 mm at 3 mA. The electrons measured 12.2 mm at 16 MV with little current dependence. Both are l… more
Date: June 10, 2005
Creator: Fisher, Alan S.; Novokhatski, A.; Turner, J. L.; Wienands, U.; Yocky, G. & Holtzapple, Robert
Partner: UNT Libraries Government Documents Department
open access

Determination of modal residues and residual flexibility for time-domain system realization

Description: A linear least-squares procedure for the determination of modal residues using time-domain system realization theory is presented. The present procedure is shown to be theoretically equivalent to residue determination in realization algorithms such as the Eigensystem Realization Algorithm (ERA) and Q-Markov COVER. However, isolating the optimal residue estimation problem from the general realization problem affords several advantages over standard realization algorithms for structural dynamics … more
Date: May 1, 1995
Creator: Alvin, K. F. & Peterson, L. D.
Partner: UNT Libraries Government Documents Department
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Transmittance of single wall carbon nanotubes

Description: The authors have measured the far infrared absorption of single wall carbon nanotube (SWNT) ropes at 1.5K and SWNT ropes in polyethylene (PE) over the range 1.5 < T < 300 K. A weak peak is observed at 28 cm{sup -1} at 1.5K for free standing SWNT samples. The frequency and temperature dependence of the peak is consistent with absorption by an E{sub 2g} symmetric, ''squash mode'', SWNT phonon, which is infrared active due to an adsorbate or disorder. The peak frequency for SWNT ropes in PE … more
Date: July 31, 2001
Creator: Holmes, W.; Hone, J.; Richards, P.L. & Zettl, A.
Partner: UNT Libraries Government Documents Department
open access

Low frequency dynamics of CO/Cu-breakdown of Born-Oppenheimer approximation

Description: Synchrotron infrared studies of adsorbates on surfaces offer the possibility of probing low frequency vibrational modes and dynamics at high resolution (1 cm{sup {minus}1}, 125 {mu}eV). Extensive experiments have been performed for ordered submonolayers of CO on low index Cu surfaces [({radical}3 {times} {radical}3)R30{degree} CO/Cu(1ll), c(2 {times} 2) CO/Cu(100) and (1 {times} 2) CO/Cu(l10)], in the 100-2500 cm{sup {minus}1} ({approximately}12.5 {minus} 312.5 MeV) range. These are the first I… more
Date: December 31, 1993
Creator: Hirschmugl, C.; Williams, G. P.; Chabal, Y. J. & Hoffmann, F. M.
Partner: UNT Libraries Government Documents Department
open access

Monolithic preamplifier employing epitaxial N-channel JFETs

Description: This paper reports the results obtained in the research program oriented to the realisation of a monolithic preamplifier for calorimetry applications at high luminosity colliders. The main purpose of the program is to arrive at a monolithic realisation with a performance as close as possible to that of discrete preamplifiers. The junction field-effect transistors employed in discrete preamplifiers have an epitaxial channel and a very heavily doped gate diffused onto it. They present the best no… more
Date: February 1, 1992
Creator: Radeka, V.; Rescia, S.; Manfredi, P. F.; Re, V. & Speziali, V.
Partner: UNT Libraries Government Documents Department
open access

Apparatus and method for separating constituents

Description: A centrifugal separator apparatus and method for improving the efficiency of the separation of constituents in a fluid stream. A cyclone separator includes an assembly for separately discharging both constituents through the same end of the separator housing. A rotary separator includes a rotary housing having a baffle disposed therein for minimizing the differential rotational velocities of the constituents in the housing, thereby decreasing turbulence, and increasing efficiency. The intensity… more
Date: December 31, 1990
Creator: Maronde, C. P. & Killmeyer, R. P., Jr.
Partner: UNT Libraries Government Documents Department
open access

FFT-oriented feedback

Description: In the SLC many feedback systems keep the beam under control. Here we concentrate on feedback systems which operate at 120 Hz or lower frequencies, so software can be used to make some decisions. The linac steering feedback uses beam position monitor data and corrects magnet settings to keep the beam orbit to the desired values (mostly flat). Looking at the Fast Fourier Transformation (FFT) of the data, a reduction in the zero and very low frequency component is observed, while on the other han… more
Date: April 1, 1993
Creator: Decker, F. J.
Partner: UNT Libraries Government Documents Department
open access

Feedback control of coupled-bunch instabilities

Description: The next generation of synchrotron light sources and particle accelerators will require active feedback systems to control multi-bunch instabilities. Stabilizing hundreds or thousands of potentially unstable modes in these accelerator designs presents many technical challenges. Feedback systems to stabilize coupled-bunch instabilities may be understood in the frequency domain (mode-based feedback) or in the time domain (bunch-by-bunch feedback). In both approaches an external amplifier system i… more
Date: May 1, 1993
Creator: Fox, J. D.; Eisen, N.; Hindi, H.; Linscott, I.; Oxoby, G.; Sapozhnikov, L. et al.
Partner: UNT Libraries Government Documents Department
open access

Effects of Collisional Zonal Flow Damping on Turbulent Transport

Description: Results from 3D global gyrokinetic particle simulations of ion temperature gradient driven microturbulence in a toroidal plasma show that the ion thermal transport level in the interior region exhibits significant dependence on the ion-ion collision frequency even in regimes where the instabilities are collisionless. This is identified as arising from the Coulomb collisional damping of turbulence-generated zonal flows.
Date: October 1, 1999
Creator: Diamond, P. H.; Hahm, T. S.; Tang, W. M.; Lee, W. W. & Lin, Z.
Partner: UNT Libraries Government Documents Department
open access

Beam-breakup calculations for the DARHT accelerator

Description: We have modeled an induction linac that will accelerate a 4-MeV, 3-kA beam of electrons to 16- to 20-MeV in 64 gaps. To suppress beam- breakup (BBU) instabilities induced by excitation of rf deflecting modes, the growth factor {Gamma} must be kept sufficiently small (e.g. < 3). On prototype DARHT cavities, rf measurements have shown that the normally degenerate TM modes are split in frequency by the asymmetry that the two pulsed-power drive rods present to the cavity. If half the cavities had v… more
Date: January 1, 1991
Creator: Allison, P.; Burns, M.J. (Los Alamos National Lab., NM (USA)); Caporaso, G.J. & Cole, A.G. (Lawrence Livermore National Lab., CA (USA))
Partner: UNT Libraries Government Documents Department
open access

Induced beam oscillations from quadrupole vibrations in the SLC linac

Description: Linac beams in the Stanford Linear Collider (SLC) were driven into oscillation by transverse vibration of lattice quadrupoles at about 7 Hz. These quadrupoles are centered on 12-meter support girders located early in the linac. The vibrations were caused by ground motion at the 0.06 {mu}m level which was amplified in the accelerator supports up to 5 {mu}m. Seismic and support vibration measurements were Fourier analyzed and a strong correlation with beam observations was observed. Subsequent mo… more
Date: June 1, 1993
Creator: Seeman, J. T.; Holtzapple, R. L. & Ross, M. C.
Partner: UNT Libraries Government Documents Department
open access

Polynomial modeling of analog-to-digital converters

Description: Analog-to-digital converters are frequently modeled as a linear polynomial plus a random process. The parameters of the linear polynomial are the familiar gain and offset of the analog-to-digital converter. The output of the random process is uniformly distributed on plus or minus the least significant bit of the analog-to-digital converter. In this paper, the transfer function of an analog-to-digital converter is modeled as a nonlinear polynomial plus a random process. This model can explain t… more
Date: January 1, 1994
Creator: Solomon, O. M. Jr.
Partner: UNT Libraries Government Documents Department
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High-gradient studies on 11.4 GHz copper accelerator structures

Description: This paper is a progress report on studies carried out at SLAC to assess the high-gradient behavior of 11.4 GHz copper accelerator structures for future linear colliders. the structures which have been examined in the last year are a 7-cavity standing-wave (SW) section and a 30-cavity traveling-wave (TW)section. Both structures are of the constant-impedance uniform-aperture type with a 2{mu}/3 phase shift per cavity. The results presented here included new information on RF breakdown, field emi… more
Date: August 1, 1992
Creator: Wang, J. W.; Curry, R. A.; Deruyter, H.; Hoag, H. A.; Koontz, R. F.; Loew, G. A. et al.
Partner: UNT Libraries Government Documents Department
open access

A methodology for assessing high intensity RF effects in aircraft

Description: Optical components have an inherent immunity to the electromagnetic interference (EMI) associated with High Intensity Radiated Fields (HIRF). The optical technology embodied in Fly-by-Light (FBL) might therefore minimize the effects of HIRF on digitally controlled systems while providing lifetime immunity to signal EMI. This is one of the primary motivations for developing FBL systems for aircraft. FBL has the potential to greatly simplify EMI certification by enabling technically acceptable la… more
Date: July 1, 1993
Creator: Zacharias, R. A.; Avalle, C. A.; Kunz, K. S.; Molau, N. E.; Pennock, S. T.; Poggio, A. J. et al.
Partner: UNT Libraries Government Documents Department
open access

Study of coupled-bunch collective effects in the ALS

Description: We present an overview of the calculated longitudinal and transverse coupled-bunch (CB) growth rates using the measured RF cavity higher order mode (HOM) impedance for the Advanced Light Source (ALS), a 1.5 GeV electron storage ring for producing synchrotron radiation. We also describe a visual method of representing the effective beam impedance and corresponding growth rates which is especially useful for understanding the dependence of growth rate on HOM frequency and Q, for determining the r… more
Date: May 1, 1993
Creator: Byrd, J. M. & Corlett, J. N.
Partner: UNT Libraries Government Documents Department
open access

Acoustic resonance spectroscopy (ARS): ARS300 operations manual, software version 2.01

Description: Acoustic Resonance Spectroscopy (ARS) is a nondestructive evaluation technology developed at the Los Alamos National Laboratory. The ARS technique is a fast, safe, and nonintrusive technique that is particularly useful when a large number of objects need to be tested. Any physical object, whether solid, hollow, or fluid filled, has many modes of vibration. These modes of vibration, commonly referred to as the natural resonant modes or resonant frequencies, are determined by the object`s shape, … more
Date: July 25, 1996
Partner: UNT Libraries Government Documents Department
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Specification of the power supply for a 6-pole combined horizontal and vertical corrector magnet

Description: Light Source Note LS-176 lists four types of corrector magnets and their power supply specifications. In order to simplify the AC operation of corrector magnets for closed orbit correction feedback, adopting a single type of corrector magnet for the whole ring is currently considered. This corrector magnet has six poles (an adaption from the ring sextupole magnet) and has coil windings producing independent horizontal and vertical bending fields. As in the other correctors, the vacuum chamber e… more
Date: February 20, 1992
Creator: Emergy, L.
Partner: UNT Libraries Government Documents Department
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Vibration study of the APS storage ring 0.8 meter quadrupole magnet/magnet support assembly

Description: The objectives of this study are as follows: Determine the vibration characteristics (frequency, damping, and mode shapes) of the magnet on prototypic supports (the actual mounting system used to mount the magnet on the girder). Measure system response to ambient floor motion. Measure the effect of various modifications to determine if the magnet response can be modified to minimize unwanted response characteristics. Modifications investigated include support schemes, increasing system damping,… more
Date: June 1, 1991
Creator: Jendrzejczyk, J. A.; Wambsganss, M. W. & Smith, R. K.
Partner: UNT Libraries Government Documents Department
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Experiment on fluidelastic instability of loosely supported tube arrays in crossflow

Description: A tube array supported by baffle plates in crossflow may be subjected to fluidelastic instability in the tube-support-plate-inactive mode. An experimental study is presented to characterize the tube motion. Three series of tests were performed to measure tube displacements as a function of flow velocity for different clearances. The motion was examined by root-mean-square values of tube displacements, power spectral densities, phase planes, Poincare maps, and Lyapunov exponents. The experimenta… more
Date: June 1, 1993
Creator: Chen, S. S.; Zhu, S. & Cai, Y.
Partner: UNT Libraries Government Documents Department
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Study of the OCS6 Lattice Using Frequency Maps

Description: Frequency maps are employed to study the baseline dampingring lattice. The study is aimed at understanding the reduced dynamicaperture in the lattice with four short straight sections compared to theone with eight short straight sections. Measures to increase the dynamicaperture based on results of this study are suggested.
Date: January 2, 2007
Creator: Reichel, Ina
Partner: UNT Libraries Government Documents Department
open access

An Extension of Implicit Monte Carlo Diffusion: Multigroup and The Difference Formulation

Description: Implicit Monte Carlo (IMC) and Implicit Monte Carlo Diffusion (IMD) are approaches to the numerical solution of the equations of radiative transfer. IMD was previously derived and numerically tested on grey, or frequency-integrated problems. In this research, we extend Implicit Monte Carlo Diffusion (IMD) to account for frequency dependence, and we implement the difference formulation as a source manipulation variance reduction technique. We derive the relevant probability distributions and pre… more
Date: April 19, 2010
Creator: Cleveland, M A; Gentile, N & Palmer, T S
Partner: UNT Libraries Government Documents Department
open access

Shielded room measurements, Final report

Description: The attenuation of electro-statically and electro-magnetically shielded rooms in the ``E,`` ``R,`` ``I,`` and ``T`` Buildings was measured so that corrective measure could be taken if the attenuation was found to be low. If remedial measures could not be taken, the shortcomings of the rooms would be known. Also, the men making the measurements should oversee construction and correct errors at the time. The work was performed by measuring the attenuation at spot frequencies over the range of fro… more
Date: February 22, 1949
Creator: Stanton, J.S.
Partner: UNT Libraries Government Documents Department
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