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Proton bunch compression strategies

Description: The paper discusses main limitations on the beam power and other machine parameters for a 4 MW proton driver for muon collider. The strongest limitation comes from a longitudinal microwave instability limiting the beam power to about 1 MW for an 8 GeV compressor ring.
Date: October 1, 2009
Creator: Lebedev, Valeri & /Fermilab
Partner: UNT Libraries Government Documents Department

Stochastic Cooling with Schottky Band Overlap

Description: Optimal use of stochastic cooling is essential to maximize the antiproton stacking rate for Tevatron Run II. Good understanding and characterization of the cooling is important for the optimization. The paper is devoted to derivation of the Fokker-Planck equations justified in the case of near or full Schottky base overlap for both longitudinal and transverse coolings.
Date: December 1, 2005
Creator: Lebedev, Valeri
Partner: UNT Libraries Government Documents Department

Amplification of Beam Acceleration in a Plasma by Plasma Instability

Description: Although achieving of high accelerating field in a plasma has been demonstrated experimentally, a practical use of such a scheme for building a large accelerator is questionable. A novel scheme of beam acceleration by a plasma wave is considered in this article. The scheme is based on an initial excitation of a plasma wave by a probe beam with comparatively modest intensity. This seed excitation is then amplified by plasma instability, so that the test beam which follows the probe beam with a small delay will be accelerated by the plasma wave with an amplitude significantly exceeding the initial amplitude of the wave. Because of small interaction between the synchronization beam and the plasma, such a scheme allows one to excite a plasma over large length and, consequently, to build a large accelerator.
Date: September 1, 1998
Creator: Lebedev, Valeri
Partner: UNT Libraries Government Documents Department

Beam physics at Tevatron complex

Description: The challenge of achieving the Tevatron Run II luminosity goal of 3 {center_dot} 10{sup 32} cm{sup -2} s{sup -1} requires high level of engineering and machine operation, good and reliable diagnostics, and clear understanding of the underlying accelerator physics. Recent history demonstrated steady increase of the Tevatron luminosity, which was supported by each of the three listed above items. This report reviews major developments in the accelerator physics, which contributed in the Run II luminosity growth. Present limitations of the luminosity and projections of further luminosity growth are also discussed.
Date: May 28, 2003
Creator: Lebedev, Valeri A.
Partner: UNT Libraries Government Documents Department

Transverse Instabilities of Coasting Beams with Space Charge

Description: Transverse beam stability is strongly affected by the beam space charge. Usually it is analyzed with the rigid-beam model. However this model is only valid when a bare (not affected by the space charge) tune spread is small compared to the space charge tune shift. This condition specifies a relatively small area of parameters which, however, is the most interesting for practical applications. The Landau damping rate and the beam Schottky spectra are computed assuming that validity condition is satisfied. The results are applied to a round Gaussian beam. The stability thresholds are described by simple fits for the cases of chromatic and octupole tune spreads.
Date: December 1, 2008
Creator: Burov, Alexey & Lebedev, Valeri
Partner: UNT Libraries Government Documents Department

The Timing Synchronization System At Jefferson Lab

Description: This paper will present the requirements and design of the Timing Synchronization System for the Continuous Electron Beam Accelerator Facility control system at Thomas Jefferson National Accelerator Facility. A clock module has been designed to reside in a VME crate with a master front-end computer and communicate with the Data Acquisition VME crates and their front-end computers via a serial fiber optic line. Configuration of the clock modules is jumper and software selectable. The application that motivated the development of the Timing Synchronization System, the Accelerator 30 Hz System, will also be presented. This system needs less than 1ms time differential between the data acquisitions on the various DAQ front-end computers in order to gather correlated information. The development of and our operational experience with this application using the new timing synchronization system will be discussed. *This work was supported by the U.S. DOE contract No. DE-AC05-84-ER40150
Date: November 1, 2001
Creator: Keesee, Marie; Dickson, Richard; Flood, Roger & Lebedev, Valeri
Partner: UNT Libraries Government Documents Department

Analysis and Design of MEBT Beam Absorber for Project-X

Description: A beam absorber is needed for a new high power accelerator to be built in Fermilab. It is called Project-X and should replace the existing linac and the 8 GeV Booster synchrotron. The beam absorber is part of the bunch-by-bunch chopper assigned to create an arbitrary bunch sequence required by experimental program. It will be located in the middle of the medium energy beam transport (MEBT) and has to remove the unnecessary bunches from the initially uniform bunch structure supplied by 2.1 MeV CW RFQ. At nominal RFQ beam current of 5 mA, the maximum power delivered to the beam absorber is about 10 kW. Beam optics requirements result in that the length allocated to the beam absorber is short ({approx}400 mm) and the beam size is small ({sigma}{approx}2mm). That yields high power density of the beam arriving to the absorber. The paper presents the thermal and mechanical analysis of one of proposed designs.
Date: May 1, 2012
Creator: Awida, Mohamed H.; Lebedev, Valeri; Yakovlev, Vyacheslav P. & /Fermilab
Partner: UNT Libraries Government Documents Department

Empirically Determined Response Matrices for On-Line Orbit and Energy Correction at Jefferson Lab

Description: Jefferson Lab uses feedback loops (less than 1 hertz update rate) to correct drifts in CEBAF's electron beam orbit and energy. Previous incarnations of these loops used response matrices that were computed by a numerical model of the machine. Jefferson Lab is transitioning this feedback system to use empirically determined response matrices whereby the software introduces small orbit or energy deviations using the loop's actuators and measures the system response with the loop's sensors. This method is in routine use for orbit correction. This paper will describe the orbit correction system and future plans to extend this method to energy correction.
Date: June 1, 2001
Creator: Harwood, Leigh; Hofler, Alicia; Joyce, Michele; Lebedev, Valeri & Bryan, David
Partner: UNT Libraries Government Documents Department

CW Room Temperature Re-Buncher for the Project X Front End

Description: At Fermilab there is a plan to construct the Project X Injector Experiment (PXIE) facility - a prototype of the front end of the Project X, a multi-MW proton source based on superconducting linac. The construction and successful operations of this facility will validate the concept for the Project X front end, thereby minimizing the primary technical risk element within the Project. The room temperature front end of the linac contains an ion source, an RFQ accelerator and a Medium Energy Beam Transport (MEBT) section comprising a high bandwidth bunch selective chopper. The MEBT length is about 10 m, so three re-bunching CW cavities are used to support the beam longitudinal dynamics. The paper reports a RF design of the re-bunchers along with preliminary beam dynamic and thermal analysis of the cavities.
Date: May 9, 2012
Creator: Romanov, Gennady; Awida, Mohamed H.; Chen, Meiyu; Gonin, Ivan V.; Kazakov, Sergey; Kostin, Roman et al.
Partner: UNT Libraries Government Documents Department

Progress in Antiproton Production at the Fermilab Tevatron Collider

Description: Fermilab Collider Run II has been ongoing since 2001. During this time peak luminosities in the Tevatron have increased from approximately 10 x 10{sup 30} cm{sup -2}sec{sup -1} to 300 x 10{sup 30} cm{sup 02}sec{sup -1}. A major contributing factor in this remarkable performance is a greatly improved antiproton production capability. Since the beginning of Run II, the average antiproton accumulation rate has increased from 2 x 10{sup 10}{anti p}/hr to about 24 x 10{sup 10}{anti p}/hr. Peak antiproton stacking rates presently exceed 28 x 10{sup 10}{anti p}/hr. The antiproton stacking rate has nearly doubled since 2005. It is this recent progress that is the focus of this paper. The process of transferring antiprotons to the Recycler Ring for subsequent transfer to the collider has been significantly restructured and streamlined, yielding additional cycle time for antiproton production. Improvements to the target station have greatly increased the antiproton yield from the production target. The performance of the Antiproton Source stochastic cooling systems has been enhanced by upgrades to the cooling electronics, accelerator lattice optimization, and improved operating procedures. In this paper, we will briefly report on each of these modifications.
Date: April 1, 2009
Creator: Pasquinelli, Ralph J.; Drendel, Brian; Gollwitzer, Keith; Johnson, Stan; Lebedev, Valeri; Leveling, Anthony et al.
Partner: UNT Libraries Government Documents Department

Lattice of the NICA Collider Rings

Description: The Nuclotron-based Ion Collider fAcility (NICA) is a new accelerator complex being constructed at JINR. It is designed for collider experiments with ions and protons and has to provide ion-ion (Au{sup 79+}) and ion-proton collisions in the energy range 1 {divided_by} 4.5 GeV/n and collisions of polarized proton-proton and deuteron-deuteron beams. Collider conceptions with constant {gamma}{sub tr} and with possibility of its variation are considered. The ring has the racetrack shape with two arcs and two long straight sections. Its circumference is about 450m. The straight sections are optimized to have {beta}* {approx} 35cm in two IPs and a possibility of final betatron tune adjustment.
Date: May 1, 2010
Creator: Sidorin, Anatoly; /Dubna, JINR; Kozlov, Oleg; /Dubna, JINR; Meshkov, Igor; /Dubna, JINR et al.
Partner: UNT Libraries Government Documents Department