| Paper |
Title |
Page |
| WEPCH055 |
A New Algorithm for the Correction of the Linear Coupling at TEVATRON
|
2047 |
| |
- Y. Alexahin, E. Gianfelice-Wendt
Fermilab, Batavia, Illinois
|
|
| |
The Fourier analysis of TBT data provides valuable information about the machine linear and non-linear optics. The recent upgrade of the Beam Position Monitors system made it possible to exploit this technique also at Tevatron. A program for the measurement and correction of the linear coupling based on this approach has been integrated in the TEVATRON control system. With respect to the method based on the empirical adjustment of the strength of the skew quadrupoles, the new method has the advantage of being faster and of allowing the measurement of the coupling also during the acceleration. Moreover it offers also information about the sum coupling coefficient and about the location of the sources of coupling.
|
|
| WEPCH058 |
Progress with Collision Optics of the Fermilab Tevatron Collider
|
2053 |
| |
- A. Valishev, Y. Alexahin, G. Annala, V.A. Lebedev, V.P. Nagaslaev
Fermilab, Batavia, Illinois
- V. Sajaev
ANL, Argonne, Illinois
|
|
| |
Recent advances in the measurement and modeling of the machine parameters and lattice functions at the Tevatron allowed modifications of the collision optics to be performed in order to increase the collider luminosity. As the result, beta functions in the two collision points were decreased from 35cm to 29cm which resulted in ~10% increase of the peak luminosity. In this report we describe the results of optics measurements and corrections. We also discuss planned improvements, including the new betatron tune working point and correction of the beta function chromaticity.
|
|
| WEPCH096 |
Measurement and Correction of the 3rd Order Resonance in the Tevatron
|
2140 |
| |
- F. Schmidt
CERN, Geneva
- Y. Alexahin, V.A. Lebedev, D. Still, A. Valishev
Fermilab, Batavia, Illinois
|
|
| |
At Fermilab Tevatron BPM system has been recently upgraded resulting much better accuracy of beam position measurements and improvements of data acquisition for turn-by-turn measurements. That allows one to record the beam position at each turn for 8000 turns for all BPMs (118 in each plane) with accuracy of about 10-20 μm. In the last decade a harmonic analysis tool has been developed at CERN that allows relating each FFT line derived from the BPM data with a particular non-linear resonance in the machine. In fact, one can even detect the longitudinal position of the sources of these resonances. Experiments have been performed at the Tevatron in which beams have been kicked to various amplitudes to analyze the 3rd order resonance. It was possible to address this rather large resonance to some purposely powered sextupoles. An alternative sextupole scheme allowed the suppression of this resonance by a good factor of 2. Lastly, the experimental data are compared with model calculations.
|
|
| WEPCH100 |
Application of the Lie-transform Perturbation Theory for the Turn-by-turn Data Analysis
|
2146 |
| |
- Y. Alexahin
Fermilab, Batavia, Illinois
|
|
| |
Harmonic analysis of turn-by-turn BPM data is a rich source of information on linear and nonlinear optics in circular machines. In the present report the normal form approach first introduced by R. Bartolini and F. Schmidt is extended on the basis of the Lie-transform perturbation theory to provide direct relation between the sources of perturbation and observable spectra of betatron oscillations. The goal is to localize strong perturbing elements, find the resonance driving terms - both absolute value and phase - that are necessary for calculation of the required adjustments in correction magnet circuits: e.g. skew-quadrupoles for linear coupling correction. The theory is nonlinear and permits to analyze higher order effects, such as coupling contribution to beta-beating and nonlinear sum resonances.
|
|