G. Wu, B. Brown, D. Capista, R. Flora, D.E. Johnson, K. Martin
{"title":"Tune control in the Fermilab Main Injector","authors":"G. Wu, B. Brown, D. Capista, R. Flora, D.E. Johnson, K. Martin","doi":"10.1109/PAC.1999.795331","DOIUrl":"https://doi.org/10.1109/PAC.1999.795331","url":null,"abstract":"We describe methods used to measure and control tunes in the Fermilab Main Injector (FMI). Emphasis is given to software implementation of the operator interface, to the front-end embedded computer system, and handling of hysteresis of main dipole and quadrupole magnets. Techniques are developed to permit control of tune of the Main Injector through several acceleration cycles: from 8.9 GeV/c to 120 GeV/c, from 8.9 GeV/c to 150 GeV/c, and from 150 GeV/c to 8.9 GeV/c. Systems which automate the complex interactions between tune measurement and the variety of ramping options are described. Some results of tune measurements and their comparison with the design model are presented.","PeriodicalId":20453,"journal":{"name":"Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)","volume":"1927 1","pages":"714-716 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87739104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Chromaticity control in the Fermilab Main Injector","authors":"G. Wu, C. Bhat, B. Brown, D.E. Johnson","doi":"10.1109/PAC.1999.795332","DOIUrl":"https://doi.org/10.1109/PAC.1999.795332","url":null,"abstract":"Chromaticity control in the Fermilab Main Injector will be important both in accelerating protons and antiprotons from 8 GeV to 150 GeV (or 120 GeV) and in decelerating recycled 150 GeV antiprotons to 8 GeV for storage in the Recycler Ring. The Main Injector has two families of sextupoles to control the chromaticity. In addition to the natural chromaticity, they must correct for sextupole fields from ramp-rate-dependent eddy currents in the dipole beam pipes and current-dependent sextupole fields in the dipole magnets. The horizontal sextupole family is required to operate in a bipolar mode below the transition energy of 20 GeV. We describe methods used to control chromaticities in the Fermilab Main Injector. Emphasis is given to the software implementation of the operator interface to the front-end ramp controllers. Results of chromaticity measurements and their comparison with the design model will be presented.","PeriodicalId":20453,"journal":{"name":"Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)","volume":"5 1","pages":"717-719 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88357617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A free interactive matching program","authors":"J. Ostiguy","doi":"10.1109/PAC.1999.792912","DOIUrl":"https://doi.org/10.1109/PAC.1999.792912","url":null,"abstract":"For physicists and engineers involved in the design and analysis of beamlines (transfer lines or insertions) the lattice function matching problem is central and can be time-consuming because it involves constrained nonlinear optimization. For such problems convergence can be difficult to obtain in general without expert human intervention. Over the years, powerful codes have been developed to assist beamline designers. The canonical example is MAD (Methodical Accelerator Design) developed at CERN by Christophe Iselin. MAD, through a specialized command language, allows one to solve a wide variety of problems, including matching problems. Although in principle, the MAD command interpreter can be run interactively, in practice the solution of a matching problem involves a sequence of independent trial runs. Unfortunately, but perhaps not surprisingly, there still exists relatively few tools exploiting the resources offered by modern environments to assist lattice designer with this routine and repetitive task. In this paper, we describe a fully interactive lattice matching program, written in C++ and assembled using freely available software components. An important feature of the code is that the evolution of the lattice functions during the nonlinear iterative process can be graphically monitored in real time; the user can dynamically interrupt the iterations at will to introduce new variables, freeze existing ones into their current state and/or modify constraints. The program runs under both UNIX and Windows NT.","PeriodicalId":20453,"journal":{"name":"Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)","volume":"48 1","pages":"2710-2712 vol.4"},"PeriodicalIF":0.0,"publicationDate":"1999-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73588549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Measurement of sextupole orbit offsets in the APS storage ring","authors":"M. Borland, E. Crosbie, N. Sereno","doi":"10.1109/pac.1999.794189","DOIUrl":"https://doi.org/10.1109/pac.1999.794189","url":null,"abstract":"Horizontal orbit errors at the sextupoles in the Advanced Photon Source (APS) storage ring can cause changes in tune and modulation of the beta functions around the ring. To determine the significance of these effects requires knowing the orbit relative to the magnetic center of the sextupoles. The method considered here to determine the horizontal beam position in a given sextupole is to measure the tune shift caused by a change in the sextupole strength. The tune shift and a beta function for the same plane uniquely determine the horizontal beam position in the sextupole. The beta function at the sextupole was determined by propagating the beta functions measured at nearby quadrupoles to the sextupole location. This method was used to measure the sextupole magnetic center offset relative to an adjacent beam position monitor (BPM) at a number of sextupole locations. We report on the successes and problems of the method as well as an alternate method.","PeriodicalId":20453,"journal":{"name":"Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)","volume":"42 1","pages":"1587-1589 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1999-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86588109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Measurements of the electron cloud in the APS storage ring","authors":"K. Harkay, R.A. Rosenburg","doi":"10.1109/PAC.1999.794207","DOIUrl":"https://doi.org/10.1109/PAC.1999.794207","url":null,"abstract":"Synchrotron radiation interacting with the vacuum chamber walls in a storage ring produce photoelectrons that can be accelerated by the beam, acquiring sufficient energy to produce secondary electrons in collisions with the walls. If the secondary-electron yield (SEY) coefficient of the wall material is greater than one, as is the case with the aluminum chambers in the 7-GeV Advanced Photon Source (APS) storage ring, a runaway condition can develop. As the electron cloud builds up along a train of stored positron or electron bunches, the possibility exists that a transverse perturbation of the head bunch will be communicated to trailing bunches due to interaction with the cloud. In order to characterize the electron cloud, a special vacuum chamber was built and inserted into the ring. The chamber contains 10 rudimentary electron-energy analyzers, as well as three targets coated with different materials. Measurements show that the intensity and electron energy distribution are highly dependent on the temporal spacing between adjacent bunches and the amount of current contained in each bunch. Furthermore, measurements using the different targets are consistent with what would be expected based on the SEY of the coatings. Data for both positron and electron beams are presented.","PeriodicalId":20453,"journal":{"name":"Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)","volume":"1 1","pages":"1641-1643 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1999-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81157046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Gallardo, R. Fernow, H. Kirk, R. Palmer, P. Lebrun, A. Moretti, A. Tollestrup, D. Kaplan, Y. Fukui
{"title":"An ionization cooling channel for muon beams based on alternating solenoids","authors":"J. Gallardo, R. Fernow, H. Kirk, R. Palmer, P. Lebrun, A. Moretti, A. Tollestrup, D. Kaplan, Y. Fukui","doi":"10.1109/PAC.1999.792136","DOIUrl":"https://doi.org/10.1109/PAC.1999.792136","url":null,"abstract":"The muon collider requires intense, cooled muon bunches to reach the required luminosity. Due to the limited lifetime of the muon, the cooling process must take place very rapidly. Ionization cooling seems to be our only option, given the large emittances of the muon beam from pion decay. However, this ionization cooling method has been found quite difficult to implement in practice. We describe a scheme based on the use of liquid hydrogen absorbers followed by RF cavities (\"pillbox\" or \"open iris\" type), embedded in a transport lattice based on high field solenoids. These solenoidal fields are reversed periodically in order to suppress the growth of the canonical angular momentum. This channel has been simulated in detail with independent codes, featuring conventional tracking in e.m. fields and detailed simulation of multiple scattering and straggling in the the absorbers and windows. These calculations show that the 15 Tesla lattice cools in 6D phase space by a factor /spl ap/2 over a distance of 20 m.","PeriodicalId":20453,"journal":{"name":"Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)","volume":"73 1","pages":"3032-3034 vol.5"},"PeriodicalIF":0.0,"publicationDate":"1999-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78145655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High current, long beam pulse with SLED","authors":"F. Decker, Z. Farkas, J. Turner","doi":"10.1109/PAC.1999.795351","DOIUrl":"https://doi.org/10.1109/PAC.1999.795351","url":null,"abstract":"A proposed, high charge, fixed target experiment (E-158) is planned to run with the highest possible energies available at the Stanford Linear Accelerator Center (SLAC), at 45 and 48 Gev. The charge is up to 6/spl middot/10/sup 11/ particles in a 370 ns long beam pulse. The SLAC Energy Development (SLED) RF system generates an increasing no-load beam energy, with a linearly decreasing slope. We show how to obtain a current variation that tracks the no-load voltage, resulting in zero energy spread. We discuss the results of a lower energy experiment that verifies the predicted charge and current at the energies required for E-158.","PeriodicalId":20453,"journal":{"name":"Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)","volume":"86 1","pages":"774-776 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85315900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Ruland, D. Arnett, G. Bowden, R. Carr, B. Dix, B. Fuss, C. Le Cocq, Z. Wolf, J. Aspenleiter, G. Rakowsky, J. Skaritka, P. Duffy, M. Libkind
{"title":"Alignment of the VISA undulator","authors":"R. Ruland, D. Arnett, G. Bowden, R. Carr, B. Dix, B. Fuss, C. Le Cocq, Z. Wolf, J. Aspenleiter, G. Rakowsky, J. Skaritka, P. Duffy, M. Libkind","doi":"10.1109/PAC.1999.795558","DOIUrl":"https://doi.org/10.1109/PAC.1999.795558","url":null,"abstract":"The Visible-Infrared SASE Amplifier (VISA) undulator consists of four 99 cm long segments. Each undulator segment is set up on a pulsed-wire bench, to characterize the magnetic properties and to locate the magnetic axis of the FODO array. Subsequently, the location of the magnetic axis, as defined by the wire, is referenced to tooling balls on each magnet segment by means of a straightness interferometer. After installation in the vacuum chamber, the four magnet segments are aligned with respect to themselves and globally to the beam line reference laser. A specially designed alignment fixture is used to mount one straightness interferometer each in the horizontal and vertical plane of the beam. The goal of these procedures is to keep the combined rms trajectory error, due to magnetic and alignment errors, to 50 /spl mu/m.","PeriodicalId":20453,"journal":{"name":"Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)","volume":"281 1","pages":"1390-1392 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76802126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multi-step lining-up correction of the CLIC trajectory","authors":"E. D'amico, G. Guignard","doi":"10.1109/PAC.1999.792316","DOIUrl":"https://doi.org/10.1109/PAC.1999.792316","url":null,"abstract":"In the CLIC main linac it is very important to minimise the trajectory excursion and consequently the emittance dilution in order to obtain the required luminosity. Several algorithms have been proposed and lately the ballistic method has proved to be very effective. The trajectory correction method described hereafter retains the main advantages of the latter while adding some interesting features. It is based on the separation of the unknown variables like the quadrupole misalignments, the offset and slope of the injection straight line and the misalignments of the beam position monitors (BPM). This is achieved by referring the trajectory relatively to the injection line and not to the average pre-alignment line and by using two trajectories each corresponding to slightly different quadrupole strengths. A reference straight line is then derived onto which the beam is bent by a kick obtained by moving the first quadrupole. The other quadrupoles are then aligned on that line. The quality of the correction depends mainly on the BPM's and micro-movers' resolution and on the stability of the quadrupole strengths. Simulation statistics show that the beam offset from the center-of the quadrupoles is typically 1.5 /spl mu/m r.m.s.","PeriodicalId":20453,"journal":{"name":"Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)","volume":"76 1","pages":"3399-3401 vol.5"},"PeriodicalIF":0.0,"publicationDate":"1999-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88202691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bunch cleaning strategies and experiments at the Advanced Photon Source","authors":"N. Sereno","doi":"10.1109/PAC.1999.792678","DOIUrl":"https://doi.org/10.1109/PAC.1999.792678","url":null,"abstract":"The Advanced Photon Source (APS) design incorporated a positron accumulator ring (PAR) as part of the injector chain. In order to increase reliability and accommodate other uses of the injector, APS will run with electrons, eliminating the need for the PAR, provided another method of eliminating RF bucket \"pollution\" in the APS is found. Satellite bunches captured from an up to 30-ns-long beam from the linac need to be removed in the injector synchrotron and storage ring. The bunch cleaning method considered here relies on driving a stripline kicker with an amplitude modulated (AM) carrier signal where the carrier is at a revolution harmonic sideband corresponding to the vertical tune.","PeriodicalId":20453,"journal":{"name":"Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)","volume":"40 1","pages":"2322-2324 vol.4"},"PeriodicalIF":0.0,"publicationDate":"1999-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82319910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}