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SLC positron damping ring optics design

Description: The basic SLAC Linear Collider operation scheme assumes the use of two damping rings, one for the e/sup -/, one for the e/sup +/, in order to reduce the colliding beam normalized emittances to 30 ..pi.. ..mu..radm hence raising the corresponding luminosity by a factor 170. The e/sup -/ damping ring optics, designed by H. Wiedemann, has been extensively studied and modelled since it's completion at the end of 1982. The e/sup +/ damping ring being built will be based on the same design except for some modifications resulting from the studies on the e/sup -/ damping ring which clearly pointed out two major weak points as far as the optics is concerned. The present paper describes the basic modifications of the ring lattice and main equipment positions in order to improve the situation in the Positron Damping Ring. 16 refs., 2 figs., 1 tab.
Date: April 1, 1985
Creator: Delahaye, J.P. & Rivkin, L.
Partner: UNT Libraries Government Documents Department

Variation of the damping partition numbers with particle energy deviation

Description: Until now, calculation of the rates of change of the damping partition numbers with particle energy took into account only the effects of quadrupole fields. It has been found however, by tracking particles in the LEP Electron Positron Accumulator that the actual variation of the damping partition numbers with energy can be increased up to a factor three by introduction of sextupole fields. The present note gives a complete analytical expression for the variation of the damping partition numbers with particle energy to first order in ..delta..p/p. This expression is then used to illustrate in three different machines the order of magnitude of each of the contributing terms. We shall see that there are terms driven mainly by small radius bending magnets which cannot be neglected. 12 references, 1 table.
Date: October 1, 1984
Creator: Delahaye, J.P. & Jaeger, J.
Partner: UNT Libraries Government Documents Department

SLC positron damping ring optics design

Description: The basic SLAC Linear Collider operation scheme assumes the use of two damping rings, one for the e/sup -/, one for the e/sup +/, in order to reduce the colliding beam normalized emittances to 30..pi.. ..mu..radm hence raising the corresponding luminosity by a factor 170. The e/sup -/ damping ring which optics was designed by H. Wiedemann, has been extensively studied and modelled since it's completion at the end of 1982. The e/sup +/ damping ring to be built soon will be based on the same design except for some modifications resulting from the studies on the e/sup -/ damping ring which clearly pointed out two major optics weak points: the extracted normalized emittances are 30 to 60% bigger than the design values, which already left no margin for unavoidable blow-up between the damping rings and the SLC interaction point, and the chromaticity correction based on distributed sextupole components provided by shaping the ends of the bending magnet poles was insufficient. Moreover the QDI quadrupoles introduce a strong coupling between transverse planes due to an undesirable skew component. The present note describes the basic modifications of the ring lattice and main equipment positions in order to improve the first two points in the Positron Damping Ring. The QDI quadrupole design has already been modified and magnets of a new type will be implemented in both damping rings.
Date: December 1, 1984
Creator: Delahaye, J.P. & Rivkin, L.
Partner: UNT Libraries Government Documents Department

First order variation of the dispersion function with particle energy deviation

Description: The variation of the dispersion function with the particle energy deviation can presently be calculated from second order transfer matrices; its periodic solution is determined numerically. The general differential equations for the dispersion function deduced from the complete equation of motion to second order are solved, using Green's function integral leading to an analytical expression of the periodic solution of the dispersion function D/sub 0/ and of the first order perturbation, D/sub 1/, with respect to energy deviation. The same method can be extended to higher order perturbations of the dispersion function. The determination of the periodic solution as well as the transportation of these two dispersion functions through any element depends only on two particular integrals. These integrals are derived for the general case of a combined function magnet, with up to second order components. The derivation includes the contribution from the edges. Chapter 2 and 3 deal with closed machines, chapter 4 applies these results to beam transport lines. These analytical expressions are then applied to a typical machine in order to illustrate the most important driving terms; the results do agree with those obtained by optics programs like MAD or DIMAT based on second order transfer matrices.
Date: December 1, 1984
Creator: Delahaye, J.P. & Jaeger, J.
Partner: UNT Libraries Government Documents Department

Performance comparisons of low emittance lattices

Description: In this paper, the results of a performance analysis of several low emittance electron storage ring lattices provided by various members of the Lattice Working Group are presented. Altogether, four lattices were investigated. There are two different functions being considered for the low beam emittance rings discussed here. The first is to serve as a Damping Ring (DR), i.e., to provide the emittance damping required for a high energy linear collider. The second is to provide beams for a short wavelength Free Electron Laser (FEL), which is envisioned to operate in the wavelength region near 40 A.
Date: May 1, 1987
Creator: Delahaye, J.P. & Zisman, M.S.
Partner: UNT Libraries Government Documents Department

Conceptual Design of the Drive Beam for a PWFA-LC

Description: Plasma Wake-Field Acceleration (PWFA) has demonstrated acceleration gradients above 50 GeV/m. Simulations have shown drive/witness bunch configurations that yield small energy spreads in the accelerated witness bunch and high energy transfer efficiency from the drive bunch to the witness bunch, ranging from 30% for a Gaussian drive bunch to 95% for bunch with triangular shaped longitudinal profile. These results open the opportunity for a linear collider that could be compact, efficient and more cost effective than the present microwave technologies. A concept of a PWFA-based Linear Collider (PWFA-LC) has been developed by the PWFA collaboration. Here we will describe the conceptual design and optimization of the drive beam, which includes the drive beam linac and distribution system. We apply experience of the CLIC drive beam design and demonstration in the CLIC Test Facility (CTF3) to this study. We discuss parameter optimization of the drive beam linac structure and evaluate the drive linac efficiency in terms of the drive beam distribution scheme and the klystron/modulator requirements.
Date: August 3, 2009
Creator: Pei, S.; Hogan, M.J.; Raubenheimer, T.O.; Seryi, A.; /SLAC; Braun, H.H. et al.
Partner: UNT Libraries Government Documents Department

Accelerator physics measurements at the damping ring

Description: Besides the optics measurements described elsewhere, machine experiments were done at the SLC damping ring to determine some of its parameters. The synchrotron radiation energy loss which gives the damping rates was measured by observing the rf-voltage dependence of the synchronous phase angle. The emittance was obtained from the synchrotron light monitor, scraper measurements and by extracting the beam through a doublet and measuring its size for different quadrupole settings. Current dependent effects such as parasitic mode losses, head tail instabilities, synchrotron and betatron frequency shifts were measured to estimate the impedance. Rf-cavity beam loading and its compensation were also studied and ion collection was investigated. All results agree reasonably well with expectations and indicate no limitations to the design performance.
Date: May 1, 1985
Creator: Rivkin, L.; Delahaye, J.P.; Wille, K.; Allen, M.; Bane, K.; Fieguth, T. et al.
Partner: UNT Libraries Government Documents Department

Status of the SLC damping rings

Description: Electron beams of full design energy 1.21 GeV and nearly full design intensity 4 x 10/sup 10/ particles/pulse (design 5 x 10/sup 10/) have been extracted from the Stanford Linac and successfully stored in the electron damping ring. Beams of less intensity have been extracted from the ring and reinjected into the Linac. The present intensity limits are not thought to be fundamental. The operating experience with the electron ring and the status of the construction of the positron ring will be discussed. 11 refs., 1 fig., 2 tabs.
Date: June 1, 1985
Creator: Hutton, A.M.; Davies-White, W.A.; Delahaye, J.P.; Fieguth, T.H.; Hofmann, A.; Jager, J. et al.
Partner: UNT Libraries Government Documents Department

Governance of the International Linear Collider Project

Description: Governance models for the International Linear Collider Project are examined in the light of experience from similar international projects around the world. Recommendations for one path which could be followed to realize the ILC successfully are outlined. The International Linear Collider (ILC) is a unique endeavour in particle physics; fully international from the outset, it has no 'host laboratory' to provide infrastructure and support. The realization of this project therefore presents unique challenges, in scientific, technical and political arenas. This document outlines the main questions that need to be answered if the ILC is to become a reality. It describes the methodology used to harness the wisdom displayed and lessons learned from current and previous large international projects. From this basis, it suggests both general principles and outlines a specific model to realize the ILC. It recognizes that there is no unique model for such a laboratory and that there are often several solutions to a particular problem. Nevertheless it proposes concrete solutions that the authors believe are currently the best choices in order to stimulate discussion and catalyze proposals as to how to bring the ILC project to fruition. The ILC Laboratory would be set up by international treaty and be governed by a strong Council to whom a Director General and an associated Directorate would report. Council would empower the Director General to give strong management to the project. It would take its decisions in a timely manner, giving appropriate weight to the financial contributions of the member states. The ILC Laboratory would be set up for a fixed term, capable of extension by agreement of all the partners. The construction of the machine would be based on a Work Breakdown Structure and value engineering and would have a common cash fund sufficiently large to allow the management ...
Date: May 31, 2012
Creator: Foster, B.; U., /Oxford; Barish, B.; /Caltech; Delahaye, J.P.; /CERN et al.
Partner: UNT Libraries Government Documents Department

ATF2 Commissioning

Description: ATF2 is a final-focus test beam line that aims to focus the low-emittance beam from the ATF damping ring to a beam size of about 37 nm, and at the same time to demonstrate nm beam stability, using numerous advanced beam diagnostics and feedback tools. The construction has been finished at the end of 2008 and the beam commissioning of ATF2 has started in December of 2008. ATF2 is constructed and commissioned by ATF international collaborations with strong US, Asian and European participation.
Date: October 30, 2009
Creator: Seryi, A.; Christian, G.; Parker, B.; Schulte, D.; Delahaye, J. -P.; Tomas, R. et al.
Partner: UNT Libraries Government Documents Department