摘要:

Various orbit correction algorithms for cyclic accelerators are discussed including eigenvector decomposition, singular value decomposition, and least‐square methods. (AIP) © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46768

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

We describe algorithms for reconstructing tune, closed‐orbit, beta‐function, and phase advance from four individual turns of beam orbit acquisition data, under the assumption of coherent, almost linear and uncoupled betatron oscillations. For estimation of the beta‐function at, and phase advance between, position monitors, we must also assume at least one anchor location consisting of two monitors separated by a drift. Assuming beam position monitors with surveying and reading errors, and assuming an imperfect lattice with gradient and surveying errors, the algorithms were submitted to a Monte Carlo analysis to find the likely measurement accuracy of the optics functions in the KAON Factory Booster ring racetrack lattice. The results of this study are reported. This paper is a much abridged version of a TRIUMF design note. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46757

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

In this article the fundamentals of spectrum analysis in beam diagnostics is discussed, where several representative particle motions in a circular accelerator are considered. The general properties of the Fourier transform are introduced first, then the coasting and the bunched beam motions in longitudinal and transverse planes are presented for single particle, multiple particle, and Schottky noise cases, respectively. To demonstrate the properties of the beam motion spectrum, time domain function are generated, and then the associated spectra are calculated and plotted. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46766

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Experimentally obtained Poincare´ maps in the resonant precessing frame for particle motion with linear coupling revealed invariant tori of the 2D Hamiltonian. Using these tori, we obtained the linear coupling strength, the tune shift with betatron amplitude coefficient and the proximity parameter to the resonance. The coupling strengh obtained with this method agreed well with that obtained from measuring the betatron tune separation of the normal modes. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46767

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The task of the orbit correction is to find the kick vector &THgr; for a given measured orbit vectorX&drarr;. We are presenting a method, in which the kick vector is expressed as linear combination of the eigenvectors. An additional advantage of this method is that it yields the smallest possible kick vector to correct the orbit. We will illustrate the application of the method to the NSLS X‐ray and UV storage rings and the resulting measurements. It will be evident, that the accuracy of this method allows the combination of the global orbit correction and local optimization of the orbit for beam lines and insertion devices.The eigenvector decomposition can also be used for optimizing kick vectors, taking advantage of the fact that eigenvectors with corresponding small eigenvalues generate negligible orbit changes. Thus, one can reduce a kick vector calculated by any other correction method and still stay within the tolerance for orbit correction.The response matrixAis defined by the equationX&drarr;=A&THgr;&drarr;, where &THgr;&drarr; is the kick vector andX&drarr; is the resulting orbit vector. SinceAis not necessarily a symmetric or even a square matrix we symmetrize it by usingAT A. Then we find the eigenvalues and eigenvectors of thisAT Amatrix. The physical interpretation of the eigenvectors for circular machines is discussed. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46769

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

A model‐based algorithmic tool was developed to search for lattice errors by a systematic analysis of orbit data in the AGS Booster synchrotron. The algorithm employs transfer matrices calculated with MAD between points in the ring. Iterative model fitting of the data allows one to find and eventually correct magnet displacements and angles or field errors.The tool, implemented on a HP‐Apollo workstation system, has proved very general and of immediate physical interpretation. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46770

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

A computer model based on neural network features is applied to the feedback problem of charged particle beam control. The SLC system is used as a starting point. (AIP)

ISSN:0094-243X    

DOI:10.1063/1.46771

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Beam position stability is one of the challenging issues associated with the operation of third‐generation synchrotron light sources. At the ESRF, experimental requirements call for stability of 1/10 of the beam sizes and divergences over eight hours. This paper will review the measures implemented to guarantee stability performance. Emphasis will be put on the closed orbit correction procedures which routinely bring orbit distortions within 0.2 mm rms and on the strategy for ensuring reproducibility of the X‐ray beam position. The combination of a periodic closed orbit correction and local static feedback leads to long‐term stability smaller than 2% of the beam size even in the more difficult vertical plane. To control rapid variations of the X‐ray beam center of mass position induced by vibrations, the switching on of a fast feedback system based on the use of X‐ray beam position monitors leads to dramatic improvements of the stability with figures in the micron range. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46772

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Local servo systems are presently used to position the 9 photon beams in SPEAR. Each servo drives a 3‐magnet orbit bump with a 50 Hz closed‐loop bandwidth. We plan to add an orbit feedback system to stabilize the beam globally. In the first stage, the global feedback will run at slow speed (<1 Hz). The long‐term goal is to combine the local and global feedback into a unified system with bandwidth exceeding 50 Hz.In this paper, we report work on initial studies of the global feedback system for SPEAR. In particular, we describe components of a comprehensive accelerator simulation program used to assess the performance of harmonic and eigenvector orbit control algorithms. This program has also been used to choose new bpm sites, and can simulate the interaction between global and local orbit feedback systems. A prototype on‐line version used for SPEAR is discussed. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46773

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

We discuss applying the regularization method of Tikhonov to the solution of inverse problems arising in accelerator operations. This approach has been successfully used for orbit correction on the NSLS storage rings, and is presently being applied to the determination of betatron functions and phases from the measured response matrix. The inverse problem of differential equations often leads to a set of integral equations of the first kind which are ill‐conditioned. The regularization method is used to combat the ill‐posedness. Our approach has been demonstrated to be very effective, robust, and capable of predicting the residual orbit after corrections. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46776

出版商:AIP    

年代:1994

数据来源: AIP