摘要:

Luminosity and performance of the colliding beam machine depend on how well the orbits of the counter rotating beams are controlled in the Interaction Regions (IRs). Two main requirements for the orbit correction in the IRs are: • Correction of the orbit perturbations caused by magnetic and alignment errors. It could be done in a similar way as in the rest of the machine (global correction). • Provision of the specific crossing orbit conditions at the Interaction Point (IP) and continuous control on the beam positions at the IP (local correction).In this paper we review our design of the orbit correction system for the SSC interaction regions, and discuss the principles of the local orbit correction at the IP. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46774

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

We are exploring the use of Neural Networks, using the SNNS simulator, for orbit control in accelerators (primarily circular accelerators) and storage rings. The orbit of the beam in those machines are measured by orbit monitors (input nodes) and controlled by orbit corrector magnets (output nodes). The physical behavior of an accelerator is changing slowly in time. Thus, an adoptive algorithm is necessary. The goal is to have a trained net which will predict the exact corrector strengths which will minimize a measured orbit. The relationship between ‘‘kick’’ from the correctors and ‘‘response’’ from the monitors is in general non‐linear and may slowly change during long‐term operation of the machine. In the study, several network architectures are examined as well as various training methods for each architecture. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46759

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The chromaticity correction system, including the nonliner correction, for the Relativistic Heavy Ion Collider (RHIC) is presented. Expected multipoles in the superconducting magnets have shown the the octupole and decapole might be large enough to reduce the momentum aperture and introduce undesirable nonlinear chromatic behavior of the machine. Simulations of these conditions have been performed with the accelerator physics tracking code TEAPOT. The chromatic dependence curves were obtained by the least square fitting. A correction to the first and the second order terms were applied by using two sextupole and two octupole circuits. The decapole correction system has been applied to correct for the third order dependence on momentum. The long term tracking studies at injection did not include the decapole correction. The studies showed that the octupole correction system significantly improves the dynamical aperture at the injection. The decapole system would not be necessary at commissioning of the machine but the correction magnets will be available. At the top energy, as to be expected, the low beta quadrupoles are the dominant source of the nonlinear momentum dependence. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46760

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Measurements of lattice parameters for the Indiana University Cyclotron Facility (IUCF) Cooler synchrotron at betatron tunes close to a sum resonance line are discussed. The measured beta functions at 36 quadrupole locations and the dispersion functions at 35 Beam Position Monitor (BPM) locations are compared with calculations. The methods used to make the above measurements and the data analysis are described. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46775

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The quadrupole strengths, beam position monitor (BPM) gains, and orbit correction magnet strengths were adjusted in a computer model of the NSLS X‐Ray ring in order to best fit the model orbit response matrix to the measured matrix. The model matrix was fit to the 4320 data points in the measured matrix with an rms difference of only 2 to 3 microns, which is due primarily to noise in the BPM measurements. The strengths of the 56 individual quadrupoles in the X‐Ray ring were determined to an accuracy of about 0.2%. The BPM and orbit corrector calibrations were also accurately determined. A thorough analysis of both random and systematic errors is included. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46761

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The harmonic content of magnetic field imperfections in the AGS Booster has been determined through careful measurements of the required field corrections of transverse resonances. An analysis of the required correction yielded amplitude and phase information which points to possible sources of imperfections. Dipole and quadrupole imperfections, which are proportional to the field of bending magnets (B), are mainly driven by any misalignment of the magnets. Quadrupole and sextupole imperfections, which are proportional to dB/dt, are given by imperfections of the eddy‐current correction system. The observations also suggest the presence of a remnant field. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46762

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The injection error monitor is now being developed for an easy tuning of the main ring beam injection at the KEK 12 GeV proton synchrotron. It is expected to perform the automatic injection tuning for the main ring by using this monitor system. The beam trajectory and the tuning ability of the injection equipment on the horizontal phase plane are obtained and confirmed by a test bench system. The injection error monitor has been proved to be efficient for the beam injection tuning. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46756

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X‐ray beams for the storage ring. The systems consist of 20 VME crates distributed around the ring, each running multiple digital signal processors (DSP) running at 4 kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. The particle and X‐ray beam position data is shared by the distributed processors through networked reflective memory. A theory of closed orbit correction using the technique of singular value decomposition (SVD) of the response matrix and simulation of its application to the APS storage ring will be discussed. This technique combines the global and local feedback systems and resolves the conflict among multiple local feedback systems due to local bump closure error. Maximum correction efficiency is achieved by feeding back the global orbit data to the local feedback systems. The effect of the vacuum chamber eddy current induced by the AC corrector magnet field for local feedback systems is compensated by digital filters. Results of experiments conducted on the X‐ray ring of the National Synchrotron Light Source and the SPEAR at Stanford Synchrotron Radiation Laboratory will be presented. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46758

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

We describe a coupling correction scheme we have developed and used to successfully reduce the vertical emittance of the NSLS X‐ray ring by a factor of 6 to below 2A˚. This gives a vertical to horizontal emittance ratio of less than 0.2%. We find the strengths of 17 skew quadrupoles to simultaneously minimize the vertical dispersion and the coupling. As a measure of coupling we utilize the shift in vertical closed orbit resulting from a change in strength of a horizontal steering magnet. Experimental measurements confirm the reduced emittance. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46763

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

From simulation studies of the RHIC lattice, we found that skew quadrupole errors and quadrupole roll misalignments in the IR triplets (where the &bgr; function can be large) produce large vertical dispersions. A simple model, using only one triplet, is applied to obtain sensitivities of vertical dispersion to skew quadrupole errors. This study revealed that measuring the vertical dispersion in the triplets is a good tool for the diagnosis of local skew quadrupole correction. © 1994 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.46764

出版商:AIP    

年代:1994

数据来源: AIP