2,550 Matching Results

Search Results

Advanced search parameters have been applied.

Transport Processes in Synchrotrons

Description: This thesis examines the evolution of beams in synchrotrons. Following an introduction to accelerator physics in Chapter 1, in Chapter 2 I describe the Fermilab E778 'diffusion' experiment. Families of sextupoles were powered to drive the 2/5 resonance, and a beam was then kicked to populate a nonlinear region of the transverse phase space. The beam was then observed over periods of approximately 30 minutes for a variety of kick amplitudes and physical apertures. In Chapter 3 comments about the analytic treatment of such systems are discussed, including the assumptions inherent in the conventional treatment. I motivate my use of a simplified model in Chapter 4 after examining common computational methods. Deriving the model from the formalism of traditional accelerator physics, I discuss its implementation on a massively parallel computer, the Intel iPSC/860 hypercube, and examine the performance of this algorithm in detail. Using the simple model to perform the numerical experiment equivalent to E778 is the subject of Chapter 5. I derive the parameters needed for the simple model based upon the physical experiment. Both three dimensional cases and cases with reduced dimensionality are run. From power supply ripple data and an electrical model of the magnet string, I compute tune modulation depths, and a subset of these are run. I conclude that tune modulation from power supply ripple is not a significant source of transport for this system. In Chapter 6, the intensities of the beams are used to compare the experimental and numerical runs, using both exponential and algebraic decays, and the algebraic form is seen to provide a better fit. The agreement between numerical and experimental results is best for fully three-dimensional runs, but the numerical results show slower decay than the experimental. Individual particles are examined, whose motion consists of stochastic motion interspersed with regular ...
Date: May 1994
Creator: Cole, Benjamin H. (Benjamin Holland)
Partner: UNT Libraries

Air-Core Strong Focusing Synchrotron

Description: The following report is based on work performed under the auspices of the U.S. Atomic Energy Commission. The purpose of this report is to describe an air-core strong focusing synchrotron and its functions.
Date: August 21, 1959
Creator: Christofilos, Nicholas C.
Partner: UNT Libraries Government Documents Department

Magnets for high intensity proton synchrotrons

Description: Recently, there has been considerable interest at Fermilab for the Proton Driver, a future high intensity proton machine. Various scenarios are under consideration, including a superconducting linac. Each scenario present some special challenges. We describe here the magnets proposed in a recent study, the Proton Driver Study II, which assumes a conventional warm synchrotron, roughly of the size of the existing FNAL booster, but capable of delivering 380 kW at 8 GeV.
Date: September 19, 2002
Creator: Jean-Francois Ostiguy, Vladimir Kashikhine and Alexander Makarov
Partner: UNT Libraries Government Documents Department

X-ray resonant scattering studies of charge and orbital ordering in Pr{sub 1{minus}z}, Ca{sub x}, MnO{sub 3}

Description: We present the results of x-ray scattering studies of the charge and orbital ordering in the manganite series Pr{sub 1{minus}z}, Ca{sub x}, MnO{sub 3} with x = 0.25, 0.4 and 0.5. The polarization and azimuthal dependence of the charge and orbital ordering in these compounds is characterized both in the resonant and nonresonant limits, and compared with the predictions of current theories. The results are qualitatively consistent with both cluster and LDA+U calculations of the electronic structure.
Date: August 14, 2000
Creator: V.ZIMMERMANN,M.; NELSON,C.S.; HILL,J.P.; GIBBS,D.; BLUME,M.; CASA,D. et al.
Partner: UNT Libraries Government Documents Department

A Synchrotron phase detector for the Fermilab Booster

Description: A synchrotron phase detector is diagnostic tool for measuring the relative phase between the accelerating field and the beam. One has been implemented in the Fermilab Booster. This is probably the first time for the Booster that the accelerating voltage seen by the beam can be experimentally determined from the information of the synchrotron phase measurement and the existing total rf accelerating voltage (RFSUM) signal without using the calculated synchrotron phase values.
Date: March 17, 2004
Creator: Yang, Xi & Padilla, Rene D
Partner: UNT Libraries Government Documents Department

Difference between BPM reading one bunch and the average of multi-bunch in Booster

Description: Differences caused by BPM reading one bunch and multi-bunch average need to be well understood before the beam parameters, such as the synchrotron tune, betatron tune, and chromaticity, are extracted from those BPM data. It is easy to perform such a study using numerical simulation other than modifying the BPM electronics.
Date: August 18, 2004
Creator: Yang, Xi
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

Beam diagnostics via model independent analysis of the turn-by-turn BPM data

Description: Model independent analysis (MIA) can be used to obtain all the eigen modes included in the turn-by-turn BPM data. Not only the synchrotron tune and betatron tune can be obtained from the fast Fourier transforms (FFT) of the temporal eigen vector of the corresponding mode, but also the error mode, which could be caused by the different gain of a BPM, can be observed in both the temporal and spatial eigen vectors of the error mode. It can be applied as a diagnostic tool for Booster.
Date: August 11, 2004
Creator: Yang, Xi
Partner: UNT Libraries Government Documents Department

STUDIES ON THE RCMS RF SYSTEM.

Description: This note addresses the various options for the Rapid Cycling Medical Synchrotron (RCMS) RF. The study was divided into three cases, namely non-tuning, tuning and filter. Each case also includes a few options. The primary study was focused on the non-tuning options. However, it was found that it requires too much driver power to cover the wide band and thus causes the cost being too high to be competitive. The proposal of RCMS is not yet clear if it can be approved or not. The results of this study might be useful to other similar machines.
Date: January 22, 2003
Creator: ZHAO,Y.
Partner: UNT Libraries Government Documents Department

METHODS FOR ADDRESSING THE PROBLEM OF THE DEPENDENCE OF THE TIME OF FLIGHT ON TRANSVERSE AMPLITUTE IN LINEAR NON-SCALING FFAGs

Description: Because the time of flight in a linear non-scaling FFAG depends on the transverse amplitude, motion in the longitudinal plane will be different for different transverse particle amplitudes. This effect, if not considered, will lead the failure of a substantial portion of the beam to be accelerated. I will first briefly review this effect. Then I will outline some techniques for addressing the problems created by the effect. In particular, I will discuss partially correcting the chromaticity and increasing the energy gain per cell. I will discuss potential problems with another technique, namely the introduction of higher harmonic cavities.
Date: November 6, 2006
Creator: Berg, J. S.
Partner: UNT Libraries Government Documents Department

LONGITUDINAL IMPEDANCE MEASUREMENT IN RHIC.

Description: The very clean Schottky spectra of gold beams in RHIC allow an accurate measurement of potential well distortion. By observing the variation in the small amplitude, incoherent synchrotron tune with intensity and bunch length, the intensity dependent longitudinal force can be measured. Dynamical effects associated with coherent motion are not important though some new dynamical effects appear. Measurements were carried out both at injection energy and store, which allowed the space charge and wall contributions to be individually determined.
Date: June 2, 2002
Creator: BLASKIEWICZ,M.; BRENNAN,J.M.; CAMERON,P. & FISCHER,W.
Partner: UNT Libraries Government Documents Department

Coherent beam-beam effects, theory & observations

Description: Current theoretical understanding of the coherent beam-beam effect as well as its experimental observations are discussed: conditions under which the coherent beambeam modes may appear, possibility of their resonant interaction (coherent resonances), stability of beam-beam oscillations in the presence of external impedances. A special attention is given to the coherent beam-beam modes of finite length bunches: the synchro-betatron coupling is shown to provide reduction in the coherent tuneshift and--at the synchrotron tune values smaller than the beam-beam parameter--Landau damping by overlapping synchrotron satellites.
Date: July 16, 2003
Creator: Alexahin, Yuri I
Partner: UNT Libraries Government Documents Department

Extensions of the longitudinal envelope equation

Description: Recently, longitudinal space charge effects have become of increased importance in a variety of dynamical situations. The CEBAF FEL injector beam dynamics shows large space-charge effects, even at 10 MeV ({gamma} {approx} 20). Space-charge dominated longitudinal motion has also been studied in the IUCF ion storage ring. Previously a longitudinal envelope equation with a self-consistent phase-space distribution has been developed, and has been of considerable use in analyzing the motion of these cases. Longitudinal motion in detailed agreement with this envelope equation has been observed at the U. of Maryland Laboratory for Plasma Research, and at the GSI electron cooling storage ring ESR, as well as at the IUCF. However, the initial presentation in ref. 4 used non-relativistic linear- accelerator bunching motion as a simplifying approximation in order to avoid inadvertent errors and minimize misprints, and must be adapted to include relativistic and/or synchrotron effects. In the present note we extend the envelope equation formulae to include relativistic, synchrotron, and acceleration effects, and define the various factors in the equations in explicit detail. The object is to obtain a set of debugged formulae for these extended cases, with all of the various factors defined explicitly, so that the formulae can be used as a reference without repetitive rederivations. The usual ambiguities over emittance definitions and units and {beta}, {gamma}, g factors should be resolved. The reader (or readers) is invited to discover any remaining errors, ambiguities or misprints for removal in the next edition. 12 refs.
Date: December 1, 1996
Creator: Neuffer, D.
Partner: UNT Libraries Government Documents Department

VARIABLE MOMENTUM COMPACTION LATTICE STUDIES.

Description: The VUV storage ring at the National Synchrotron Light Source was used to study the impact of changes in the momentum compaction factors over a large range from positive to negative values. Changes in bunch length and synchrotron tune were measured versus current and RF parameters for these different lattices. By controlling both the first and second-order momentum compaction factors, a lattice was developed in which a pair of alpha buckets was created within the energy aperture of the vacuum chamber and beam was stored simultaneously in both buckets.
Date: March 29, 1999
Creator: KRAMER,S. & MURPHY,J.B.
Partner: UNT Libraries Government Documents Department

Trends and Opportunities in Light Source Development

Description: After a decade of rather quiet growth for FELs there is now a lot of activity in the light source community. This is the result of a combination of factors including successful operation of the third generation light sources, the establishment of a very productive user community at both synchrotrons and FELs, and the continuing technical improvements of accelerators and related technology which allow ever more challenging machines to be considered. There are a number of themes that carry this development including pushing wavelengths shorter, brightnesses higher, pulses shorter, increasing average power, and providing for multiple synchronized photon beams with multiple wavelengths. This talk will discuss some of the plans and proposals currently circulating and attempt to provide a glimpse into the near future of our field by illustrating the technologies that drive source development.
Date: August 1, 2001
Creator: Neil, George R.
Partner: UNT Libraries Government Documents Department

Multitechnique Analysis of the Lattice Structures of Highly Siliceous Zeolites

Description: The combined use of high-resolution solid state NMR techniques (both 1D and 2D) with synchrotron-based powder x-ray diffraction studies yields detailed information on the lattice structures of highly siliceous zeolites. The two methods are complementary, the former probing short range ordering and structures while the latter is sensitive to long range orderings and periodicities.
Date: August 26, 1999
Creator: Fyfe, C. A.; Gies, H.; Kokotailo, G. T.; Feng, Y.; Strobl, H.; Marler, B. et al.
Partner: UNT Libraries Government Documents Department