Lebedev, V.A.

Paper	Title	Page
TUXPA01	Tevatron Operational Status and Possible Lessons for the LHC	900
	V.A. Lebedev Fermilab, Batavia, Illinois
	This talk will provide an overview of the Tevatron Run II luminosity progress and plans, including SC magnet measurements and modeling of field errors in view of the LHC operation, electron cooling progress and results, slip-stacking and optimized use of the injectors for antiproton production, and improvements in the antiproton source.
	Transparencies
WEPCH057	Measurement and Optimization of the Lattice Functions in the Debuncher Ring at Fermilab	2050
	V.P. Nagaslaev, K. Gollwitzer, V.A. Lebedev, A. Valishev Fermilab, Batavia, Illinois V. Sajaev ANL, Argonne, Illinois
	A goal of the Tevatron Run-II upgrade requires substantial increase of antiproton production. The central step towards this goal is increasing the Debuncher ring admittance. Detailed understanding of the Debuncher's optics, aperture limitations and lattice functions is necessary. The method of the response matrix optimization has been used to determine quadrupole errors and corrections to the design functions. The measurement accuracy is about 5% due to the Beam Position Monitor system resolution and the small number of steering elements in the machine. We have used these accurate measurements to redesign the machine optics to maximize the acceptance of the Debuncher where the main limiting apertures are the stochastic cooling pickups and kickers. Accuracy of the measurements and the limitations are discussed as well as details of the optics modification.
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.
THPCH065	Suppression of Transverse Instability by a Digital Damper	2934
	A.V. Burov, V.A. Lebedev Fermilab, Batavia, Illinois
	When a beam phase space density increases, it makes its motion intrinsically unstable. To suppress the instabilities, dampers are required. With a progress of digital technology, digital dampers are getting to be more and more preferable, compared with analog ones. Conversion of an analog signal into digital one is described by a linear operator with explicit time dependence. Thus, the analog-digital converter (ADC) does not preserve a signal frequency. Instead, a monochromatic input signal is transformed into a mixture of all possible frequencies, combining the input one with multiples of the sampling frequency. Stability analysis has to include a cross-talk between all these combined frequencies. In this paper, we are analyzing a problem of stability for beam transverse microwave oscillations in a presence of digital damper; the impedance and the space charge are taken into account. The developed formalism is applied for antiproton beam in the Recycler Ring at Fermilab.