IPAC2012 - List of Keywords (closed-orbit)

Paper	Title	Other Keywords	Page
MOPPC021	Explore the Possibility of Accelerating Polarized He-3 Beam in RHIC	resonance, proton, betatron, neutron	172
	M. Bai, E.D. Courant, W. Fischer, V. Ptitsyn, T. Roser BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. As the world’s first high energy polarized proton collider, RHIC has made significant progress in measuring the proton spin structure in the past decade. In order to have better understanding of the contribution of up and down quarks to the proton spin structure, collisions of high energy polarized neutron beams are required. In this paper, we present studies of accelerating polarized Helium-3 in RHIC with the current dual snake configuration. The possibilities of adding two more pairs of snakes for accelerating polarized He-3 were explored. Results of a six snake configuration in RHIC are also reported in the paper.

MOPPC024	Modelling of the AGS Using Zgoubi - Status	simulation, optics, multipole, coupling	181
	F. Méot, L. A. Ahrens, Y. Dutheil, J.W. Glenn, H. Huang, T. Roser, V. Schoefer, N. Tsoupas BNL, Upton, Long Island, New York, USA
	A computer model, based on the ray-tracing code Zgoubi, is being developed in view of on-line simulation of the RHIC injector AGS, and of beam and spin dynamics simulations and studies in the presence of the cold and warm helical partial snakes. A status of this work is given here.

MOPPC076	New Features of the Parallel TRACY for Nonlinear Beam Dynamics	lattice, dynamic-aperture, sextupole, betatron	310
	M.-S. Chiu, H.-P. Chang NSRRC, Hsinchu, Taiwan
	The TRACY code is used to analyze and simulate the nonlinear beam dynamics of the designed lattice. To speed up the lattice design flow, we parallelized the TRACY by MPI and developed a GUI by GTK+ to integrate the functions of TRACY and added a function of nonlinear optimization adapted from OPA, which is used to optimize the nonlinear driving terms by powell algorithm. The GUI is used for parameter input and data visualization. The procedures of nonlinear optimization and beam dynamics analysis are integrated and streamlined. Users do not need to write and compile the code any more. The results will be demonstrated in this report.

MOPPD021	An Experimental Investigation of Slow Integer Tune Crossing in the EMMA Non-scaling FFAG	acceleration, resonance, simulation, proton	412
	J.M. Garland, H.L. Owen UMAN, Manchester, United Kingdom D.J. Kelliher, S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Student STFC grant number: ST/G004277/1. Results are presented from a slow integer tune crossing experiment performed in the EMMA accelerator. Under nominal conditions EMMA accelerates an electron beam from 10–20 MeV rapidly in 5–10 turns in a novel “serpentine” channel causing several transverse integer tunes to be crossed. During this rapid acceleration it has been shown that the betatron amplitude of the beam does not grow. If the potential of non-scaling FFAGs were to be realized in such fields as high-current proton acceleration then tune space would be crossed slower with acceleration in an RF bucket. The crossing speed in a non-scaling FFAG is in a previously unstudied intermediate region and hence conventional crossing theory may not apply. It was proposed to observe the effects on betatron amplitude when a beam crosses integer tunes by the variation of tune with momentum over a range of crossing speeds derived from different acceleration rates. This method can be realized by synchrotron acceleration inside a stable RF bucket. Betatron amplitude growth and beam loss as a function of turn are explored when crossing an integer tune and a relationship between crossing speed and these quantities is established.

MOPPD071	Error Localization in RHIC by Fitting Difference Orbit	storage-ring, feedback, dipole, optics	526
	C. Liu, M.G. Minty, V. Ptitsyn BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Many errors in an accelerator are evidenced as transverse kicks to the beam, which distort the beam trajectory. Therefore, the information of the errors are imprinted in the distorted orbits, which are different from what would be predicted by the optics model. In this paper, we introduce an algorithm for fitting the orbit based on an on-line optics model. We apply the algorithm to localize the location of the elusive source of vertical diurnal variations observed in RHIC, and analyze D0/Dx errors in local coupling measurement.

MOPPD075	Optimization of the Collimation System for the CSNS/RCS	collimation, beam-losses, injection, scattering	538
	N. Wang, M.Y. Huang, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China
	Beam loss induced activation of the accelerator components is one of the primary concerns in designing a high intensity machine. The uncontrolled beam loss is required to be less than 1 W/m for hands-on maintenance of the machine. A two stage collimation system is designed in the Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) to localize the beam losses in a restricted area. The parameters of the collimator are optimized in order to obtain high collimation efficiency. The final design of the collimation system is presented. The reliability of the collimation system is estimated for different working points and with closed orbit errors.

MOPPR009	Dynamic Closed Orbit Correction During the Fast Energy Ramp of ELSA	polarization, acceleration, electron, controls	789
	J.-P. Thiry, A. Balling, A. Dieckmann, F. Frommberger, W. Hillert ELSA, Bonn, Germany
	ELSA is a fast ramping stretcher ring supplying polarized electrons to hadron physics experiments. To preserve the degreee of polarization, it is necessary to continuously correct the vertical orbit when accelerating the beam from 1.2 GeV to 2.4 GeV. Acceleration is performed within 300 ms, thus with a ramping speed of 4 GeV/s. During the acceleration, beam positions are measured at a rate of 1 kHz using 32 beam position monitors, which are mounted close to the quadrupole magnets. The demanding task is to achieve a vertical rms deviation not exceeding 50 μm all along the fast energy ramp. Therefore, dynamic orbit corrections are applied by means of offline feed-forward techniques, driving 32 vertical steerer magnets which can change currents in less than 10 ms. In our contribution, we show the used concepts and the implementation of the precise closed orbit correction system at ELSA.

MOPPR030	Various Methods to Measure the Betatron Tune of the Synchrotoron	betatron, pick-up, synchrotron, injection	843
	S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan
	Generally in the synchrotron, the frequency of transverse oscillation of the bunched beam for each single turn (usually called betatron tune or just "tune") is one of fundamental controllable knobs to avoid the instability of the accelerator. In this report, it is not mentioned about the effect to the beam instability but it is focused to various methods to measure the betatron tune by using bunch-by-bunch transverse beam position. The following items will be presented, (1) least square fitting to the time-domain beam position at specific location. (2) peak finding of the frequency-domain beam position at specific location. (3) phase space analysis of the beam position at specific location.(4) frequency-domain analysis of the beam position in the normalized coordinate at many locations in the ring orbit. For the application to the real accelerator, data of the J-PARC (Japan Proton Accelerator Research Complex) will be shown.

TUXA03	Increasing the AGS Beam Polarization with 80 Tune Jumps	resonance, polarization, quadrupole, emittance	1015
	V. Schoefer, L. A. Ahrens, M. Bai, E.D. Courant, W. Fu, C.J. Gardner, J.W. Glenn, H. Huang, F. Lin, A.U. Luccio, J.-L. Mi, J. Morris, P.J. Rosas, T. Roser, P. Thieberger, N. Tsoupas, A. Zelenski, K. Zeno BNL, Upton, Long Island, New York, USA
	Vertical depolarizing resonances in the AGS are removed by partial Siberian snakes. These magnets move the stable spin direction and lead to horizontal depolarizing resonances. The tune jump quadrupole system increases the crossing rate for horizontal resonances by a factor of six. This presentation will review the fundamental mechanism of depolarizing resonances, the partial Siberian snake solution and describe recent experimental evidence at the AGS demonstrating improvements to beam polarization and the beam dynamics challenges posed by the tune jump.
	Slides TUXA03 [5.199 MB]

TUPPC017	Orbit and Optics Correction to Realize Designed Machine Performance	optics, emittance, lattice, target	1194
	Y. Seimiya, S. Kamada, A. Morita, K. Ohmi, K. Oide KEK, Ibaraki, Japan
	It is difficult for actual accelerators to achieve the designed machine performance without appropriate correction or adjustment of magnet errors. By correction as magnets are aligned to design orbit, we aim to be realized the designed machine performance. However, it is not easy to estimate the design orbit in real accelerators. In KEKB and PF, beam position monitor(BPM) can be calibrated to the center of quadrupole magnet(QM). BPM and QM misalignments (except rotation misalignment) referring to design orbit can be estimated using assumption that these misalignments are coincident. This is, design orbit at BPM and QM can be derived.

TUPPC022	Straight Scaling FFAG Experiment	emittance, linac, vacuum, instrumentation	1209
	J.-B. Lagrange, Y. Ishi, Y. Kuriyama, Y. Mori, R. Nakano, B. Qin, T. Uesugi, E. Yamakawa Kyoto University, Research Reactor Institute, Osaka, Japan Y. Niwa, K. Okabe, I. Sakai University of Fukui, Faculty of Engineering, Fukui, Japan
	Straight scaling FFAG experiment has been done at Kyoto University research reactor institute. Details and results are presented here.

TUPPC046	Further Analysis of Real Beam Line Optics from a Synthetic Beam	optics, coupling, linac, electron	1269
	R.M. Bodenstein UVa, Charlottesville, Virginia, USA Y. Roblin, M.G. Tiefenback JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a license to publish or reproduce this manuscript for U.S. Government purposes. Standard closed-orbit techniques for Twiss parameter measurement are not applicable to the open-ended Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. The evolution of selected sets of real orbits in the accelerator models the behavior of a “synthetic” beam. This process will be validated against beam profile-based Twiss parameter measurements and should provide the distributed optical information needed to optimize beamline tuning for an open-ended system. This work will discuss the current and future states of this technique, as well as an example of its use in the CEBAF machine.

TUPPC058	Beam Energy Variation with Dipole Fault	dipole, sextupole, simulation, lattice	1305
	Y. Li, S. Krinsky BNL, Upton, Long Island, New York, USA
	Funding: Supported by Department of Energy Contract No. DE-AC02-98CH10886. The effect of dipole faults and closed orbit correction on the beam energy is studied both analytically and numerically using the ELEGANT code. Motivated by top-off safety analysis, we consider the case of single dipole faults and study how large an error can be compensated by the closed orbit correction system before the beam is lost.

TUPPC098	Electron Polarization in the Medium-Energy Electron-Ion Collider at JLAB	polarization, electron, solenoid, dipole	1386
	F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang JLAB, Newport News, Virginia, USA D.P. Barber DESY, Hamburg, Germany
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A key feature of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is high polarization (over 80%) of the electron beam at all collision points for the particle physics program. The equilibrium electron polarization is arranged to be vertical in the arcs of the figure-8 collider ring of the MEIC and anti-parallel to the arc dipole magnetic fields, in order to take advantage of the preservation of polarization by the Sokolov-Ternov (S-T) effect. Longitudinal polarization is achieved at collision points by utilizing energy-independent universal spin rotators each of which consists of a set of solenoids and dipoles placed at the end of an arc. The equilibrium beam polarization and its lifetime depend on competition between the S-T effect and radiative depolarization. The latter must be suppressed by spin matching. This paper reports on investigations of polarization in the MEIC electron collider ring and a preliminary estimate of beam polarization from calculations using the code SLICK. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.

TUPPD015	Optimization of Muon Capturing in g-2 Ring	kicker, betatron, vacuum, impedance	1440
	A.A. Mikhailichenko CLASSE, Ithaca, New York, USA D.L. Rubin Cornell University, Ithaca, New York, USA
	We describe optimization procedure for muons capturing in g-2 ring under reconstruction at FERMILAB. This procedure includes both the beam dynamics consideration and HV inflector geometry and technique. Some engineering aspects of HV inflector and pulser are presented in detail.

TUPPD021	Orbit Correction in the EMMA Non-scaling FFAG – Simulation and Experimental Results	quadrupole, betatron, pick-up, target	1455
	D.J. Kelliher, S. Machida, S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom J.S. Berg BNL, Upton, Long Island, New York, USA J.K. Jones, B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom E. Keil Honorary CERN Staff Member, Berlin, Germany I.W. Kirkman The University of Liverpool, Liverpool, United Kingdom
	The non-scaling FFAG EMMA (Electron Model for Many Applications) is currently in operation at Daresbury Laboratory, UK. Since the lattice is made up solely of linear elements, the betatron tune varies strongly over the momentum range according to the natural chromaticity. Orbit correction is complicated by the resulting variation in response to corrector magnet settings. We consider a method to optimise correction over a range of fixed momenta and discuss experimental results. Measurements of the closed orbit and response matrix are included.

TUPPP028	A Study of Girder Alignment with Survey Measurements In the Diamond Storage Ring	survey, storage-ring, sextupole, insertion	1674
	M. Apollonio, R. Bartolini, R.T. Fielder, W.J. Hoffman, J. Kay, I.P.S. Martin, B. Singh Diamond, Oxfordshire, United Kingdom
	Using a model of the Diamond storage ring which includes displacements and rotations of the 74 magnet girders an attempt has been made to correlate survey data with the corrector magnet (CM) strengths required for a zero orbit. We then use the model to deduce the most effective girder movements that will bring about a reduction in corrector strength. We describe the results of these studies, and suggest a test with a deliberately displaced girder and the effect on corrector strengths, aimed at enhancing our understanding of the system

WEPPP084	Weighted SVD Algorithm for Close-Orbit Correction and 10 Hz Feedback in RHIC	feedback, electron, proton, ion	2906
	C. Liu, R.L. Hulsart, A. Marusic, R.J. Michnoff, M.G. Minty, V. Ptitsyn BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Measurements of the beam position along an accelerator are typically treated equally using standard SVD-based orbit correction algorithms so distributing the residual errors, modulo the local beta function, equally at the measurement locations. However, sometimes a more stable orbit at select locations is desirable. In this paper, we introduce an algorithm for weighting the beam position measurements to achieve a more stable local orbit. The results of its application to close-orbit correction and 10-Hz orbit feedback will be shown and analyzed.

WEPPR006	Serpentine Acceleration in Scaling FFAG	acceleration, proton, injection, betatron	2946
	E. Yamakawa, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan K. Okabe, I. Sakai University of Fukui, Faculty of Engineering, Fukui, Japan
	A serpentine acceleration in scaling FFAG accelerator is examined. In this scheme, high-energy and high-current beam can be obtained in non-relativistic energy region. Longitudinal hamiltonian is derived analytically. Experiment to demonstrate a serpentine acceleration in scaling FFAG is done.

THPPR064	MW-class 800 MeV/n H²⁺ SC-Cyclotron for ADC application, Design Study and Goals	cyclotron, extraction, injection, target	4121
	F. Méot, T. Roser, W.-T. Weng BNL, Upton, Long Island, New York, USA L. Calabretta INFN/LNS, Catania, Italy A. Calanna CSFNSM, Catania, Italy
	A megawatt class isochronous cyclotron is a potential candidate for accelerator driven systems, as in the subcritical-fission molten-salt reactor application. A scheme for a 800 MeV/nucleon cyclotron accelerating molecular H₂⁺ has been derived from on-going proton driver design studies for neutrino beam production. The present paper reports on beam dynamics studies regarding that cyclotron, exploiting its superconducting coil magnetic sector OPERA field map. These studies are aimed at assessing lattice properties as accelerated orbit, phase oscillations, tunes, beam envelopes and other resonance effects.

Paper

Title

Other Keywords

Page

MOPPC021

Explore the Possibility of Accelerating Polarized He-3 Beam in RHIC

resonance, proton, betatron, neutron

172

M. Bai, E.D. Courant, W. Fischer, V. Ptitsyn, T. Roser
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
As the world’s first high energy polarized proton collider, RHIC has made significant progress in measuring the proton spin structure in the past decade. In order to have better understanding of the contribution of up and down quarks to the proton spin structure, collisions of high energy polarized neutron beams are required. In this paper, we present studies of accelerating polarized Helium-3 in RHIC with the current dual snake configuration. The possibilities of adding two more pairs of snakes for accelerating polarized He-3 were explored. Results of a six snake configuration in RHIC are also reported in the paper.

MOPPC024

Modelling of the AGS Using Zgoubi - Status

simulation, optics, multipole, coupling

181

F. Méot, L. A. Ahrens, Y. Dutheil, J.W. Glenn, H. Huang, T. Roser, V. Schoefer, N. Tsoupas
BNL, Upton, Long Island, New York, USA

A computer model, based on the ray-tracing code Zgoubi, is being developed in view of on-line simulation of the RHIC injector AGS, and of beam and spin dynamics simulations and studies in the presence of the cold and warm helical partial snakes. A status of this work is given here.

MOPPC076

New Features of the Parallel TRACY for Nonlinear Beam Dynamics

lattice, dynamic-aperture, sextupole, betatron

310

M.-S. Chiu, H.-P. Chang
NSRRC, Hsinchu, Taiwan

The TRACY code is used to analyze and simulate the nonlinear beam dynamics of the designed lattice. To speed up the lattice design flow, we parallelized the TRACY by MPI and developed a GUI by GTK+ to integrate the functions of TRACY and added a function of nonlinear optimization adapted from OPA, which is used to optimize the nonlinear driving terms by powell algorithm. The GUI is used for parameter input and data visualization. The procedures of nonlinear optimization and beam dynamics analysis are integrated and streamlined. Users do not need to write and compile the code any more. The results will be demonstrated in this report.

MOPPD021

An Experimental Investigation of Slow Integer Tune Crossing in the EMMA Non-scaling FFAG

acceleration, resonance, simulation, proton

412

J.M. Garland, H.L. Owen
UMAN, Manchester, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Student STFC grant number: ST/G004277/1.
Results are presented from a slow integer tune crossing experiment performed in the EMMA accelerator. Under nominal conditions EMMA accelerates an electron beam from 10–20 MeV rapidly in 5–10 turns in a novel “serpentine” channel causing several transverse integer tunes to be crossed. During this rapid acceleration it has been shown that the betatron amplitude of the beam does not grow. If the potential of non-scaling FFAGs were to be realized in such fields as high-current proton acceleration then tune space would be crossed slower with acceleration in an RF bucket. The crossing speed in a non-scaling FFAG is in a previously unstudied intermediate region and hence conventional crossing theory may not apply. It was proposed to observe the effects on betatron amplitude when a beam crosses integer tunes by the variation of tune with momentum over a range of crossing speeds derived from different acceleration rates. This method can be realized by synchrotron acceleration inside a stable RF bucket. Betatron amplitude growth and beam loss as a function of turn are explored when crossing an integer tune and a relationship between crossing speed and these quantities is established.

MOPPD071

Error Localization in RHIC by Fitting Difference Orbit

storage-ring, feedback, dipole, optics

526

C. Liu, M.G. Minty, V. Ptitsyn
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Many errors in an accelerator are evidenced as transverse kicks to the beam, which distort the beam trajectory. Therefore, the information of the errors are imprinted in the distorted orbits, which are different from what would be predicted by the optics model. In this paper, we introduce an algorithm for fitting the orbit based on an on-line optics model. We apply the algorithm to localize the location of the elusive source of vertical diurnal variations observed in RHIC, and analyze D0/Dx errors in local coupling measurement.

MOPPD075

Optimization of the Collimation System for the CSNS/RCS

collimation, beam-losses, injection, scattering

538

N. Wang, M.Y. Huang, S. Wang, S.Y. Xu
IHEP, Beijing, People's Republic of China

Beam loss induced activation of the accelerator components is one of the primary concerns in designing a high intensity machine. The uncontrolled beam loss is required to be less than 1 W/m for hands-on maintenance of the machine. A two stage collimation system is designed in the Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) to localize the beam losses in a restricted area. The parameters of the collimator are optimized in order to obtain high collimation efficiency. The final design of the collimation system is presented. The reliability of the collimation system is estimated for different working points and with closed orbit errors.

MOPPR009

Dynamic Closed Orbit Correction During the Fast Energy Ramp of ELSA

polarization, acceleration, electron, controls

789

J.-P. Thiry, A. Balling, A. Dieckmann, F. Frommberger, W. Hillert
ELSA, Bonn, Germany

ELSA is a fast ramping stretcher ring supplying polarized electrons to hadron physics experiments. To preserve the degreee of polarization, it is necessary to continuously correct the vertical orbit when accelerating the beam from 1.2 GeV to 2.4 GeV. Acceleration is performed within 300 ms, thus with a ramping speed of 4 GeV/s. During the acceleration, beam positions are measured at a rate of 1 kHz using 32 beam position monitors, which are mounted close to the quadrupole magnets. The demanding task is to achieve a vertical rms deviation not exceeding 50 μm all along the fast energy ramp. Therefore, dynamic orbit corrections are applied by means of offline feed-forward techniques, driving 32 vertical steerer magnets which can change currents in less than 10 ms. In our contribution, we show the used concepts and the implementation of the precise closed orbit correction system at ELSA.

MOPPR030

Various Methods to Measure the Betatron Tune of the Synchrotoron

betatron, pick-up, synchrotron, injection

843

S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan

Generally in the synchrotron, the frequency of transverse oscillation of the bunched beam for each single turn (usually called betatron tune or just "tune") is one of fundamental controllable knobs to avoid the instability of the accelerator. In this report, it is not mentioned about the effect to the beam instability but it is focused to various methods to measure the betatron tune by using bunch-by-bunch transverse beam position. The following items will be presented, (1) least square fitting to the time-domain beam position at specific location. (2) peak finding of the frequency-domain beam position at specific location. (3) phase space analysis of the beam position at specific location.(4) frequency-domain analysis of the beam position in the normalized coordinate at many locations in the ring orbit. For the application to the real accelerator, data of the J-PARC (Japan Proton Accelerator Research Complex) will be shown.

TUXA03

Increasing the AGS Beam Polarization with 80 Tune Jumps

resonance, polarization, quadrupole, emittance

1015

V. Schoefer, L. A. Ahrens, M. Bai, E.D. Courant, W. Fu, C.J. Gardner, J.W. Glenn, H. Huang, F. Lin, A.U. Luccio, J.-L. Mi, J. Morris, P.J. Rosas, T. Roser, P. Thieberger, N. Tsoupas, A. Zelenski, K. Zeno
BNL, Upton, Long Island, New York, USA

Vertical depolarizing resonances in the AGS are removed by partial Siberian snakes. These magnets move the stable spin direction and lead to horizontal depolarizing resonances. The tune jump quadrupole system increases the crossing rate for horizontal resonances by a factor of six. This presentation will review the fundamental mechanism of depolarizing resonances, the partial Siberian snake solution and describe recent experimental evidence at the AGS demonstrating improvements to beam polarization and the beam dynamics challenges posed by the tune jump.

Slides TUXA03 [5.199 MB]

TUPPC017

Orbit and Optics Correction to Realize Designed Machine Performance

optics, emittance, lattice, target

1194

Y. Seimiya, S. Kamada, A. Morita, K. Ohmi, K. Oide
KEK, Ibaraki, Japan

It is difficult for actual accelerators to achieve the designed machine performance without appropriate correction or adjustment of magnet errors. By correction as magnets are aligned to design orbit, we aim to be realized the designed machine performance. However, it is not easy to estimate the design orbit in real accelerators. In KEKB and PF, beam position monitor(BPM) can be calibrated to the center of quadrupole magnet(QM). BPM and QM misalignments (except rotation misalignment) referring to design orbit can be estimated using assumption that these misalignments are coincident. This is, design orbit at BPM and QM can be derived.

TUPPC022

Straight Scaling FFAG Experiment

emittance, linac, vacuum, instrumentation

1209

J.-B. Lagrange, Y. Ishi, Y. Kuriyama, Y. Mori, R. Nakano, B. Qin, T. Uesugi, E. Yamakawa
Kyoto University, Research Reactor Institute, Osaka, Japan
Y. Niwa, K. Okabe, I. Sakai
University of Fukui, Faculty of Engineering, Fukui, Japan

Straight scaling FFAG experiment has been done at Kyoto University research reactor institute. Details and results are presented here.

TUPPC046

Further Analysis of Real Beam Line Optics from a Synthetic Beam

optics, coupling, linac, electron

1269

R.M. Bodenstein
UVa, Charlottesville, Virginia, USA
Y. Roblin, M.G. Tiefenback
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a license to publish or reproduce this manuscript for U.S. Government purposes.
Standard closed-orbit techniques for Twiss parameter measurement are not applicable to the open-ended Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. The evolution of selected sets of real orbits in the accelerator models the behavior of a “synthetic” beam. This process will be validated against beam profile-based Twiss parameter measurements and should provide the distributed optical information needed to optimize beamline tuning for an open-ended system. This work will discuss the current and future states of this technique, as well as an example of its use in the CEBAF machine.

TUPPC058

Beam Energy Variation with Dipole Fault

dipole, sextupole, simulation, lattice

1305

Y. Li, S. Krinsky
BNL, Upton, Long Island, New York, USA

Funding: Supported by Department of Energy Contract No. DE-AC02-98CH10886.
The effect of dipole faults and closed orbit correction on the beam energy is studied both analytically and numerically using the ELEGANT code. Motivated by top-off safety analysis, we consider the case of single dipole faults and study how large an error can be compensated by the closed orbit correction system before the beam is lost.

TUPPC098

Electron Polarization in the Medium-Energy Electron-Ion Collider at JLAB

polarization, electron, solenoid, dipole

1386

F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang
JLAB, Newport News, Virginia, USA
D.P. Barber
DESY, Hamburg, Germany

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A key feature of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is high polarization (over 80%) of the electron beam at all collision points for the particle physics program. The equilibrium electron polarization is arranged to be vertical in the arcs of the figure-8 collider ring of the MEIC and anti-parallel to the arc dipole magnetic fields, in order to take advantage of the preservation of polarization by the Sokolov-Ternov (S-T) effect. Longitudinal polarization is achieved at collision points by utilizing energy-independent universal spin rotators each of which consists of a set of solenoids and dipoles placed at the end of an arc. The equilibrium beam polarization and its lifetime depend on competition between the S-T effect and radiative depolarization. The latter must be suppressed by spin matching. This paper reports on investigations of polarization in the MEIC electron collider ring and a preliminary estimate of beam polarization from calculations using the code SLICK.
Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.

TUPPD015

Optimization of Muon Capturing in g-2 Ring

kicker, betatron, vacuum, impedance

1440

A.A. Mikhailichenko
CLASSE, Ithaca, New York, USA
D.L. Rubin
Cornell University, Ithaca, New York, USA

We describe optimization procedure for muons capturing in g-2 ring under reconstruction at FERMILAB. This procedure includes both the beam dynamics consideration and HV inflector geometry and technique. Some engineering aspects of HV inflector and pulser are presented in detail.

TUPPD021

Orbit Correction in the EMMA Non-scaling FFAG – Simulation and Experimental Results

quadrupole, betatron, pick-up, target

1455

D.J. Kelliher, S. Machida, S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
J.S. Berg
BNL, Upton, Long Island, New York, USA
J.K. Jones, B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
E. Keil
Honorary CERN Staff Member, Berlin, Germany
I.W. Kirkman
The University of Liverpool, Liverpool, United Kingdom

The non-scaling FFAG EMMA (Electron Model for Many Applications) is currently in operation at Daresbury Laboratory, UK. Since the lattice is made up solely of linear elements, the betatron tune varies strongly over the momentum range according to the natural chromaticity. Orbit correction is complicated by the resulting variation in response to corrector magnet settings. We consider a method to optimise correction over a range of fixed momenta and discuss experimental results. Measurements of the closed orbit and response matrix are included.

TUPPP028

A Study of Girder Alignment with Survey Measurements In the Diamond Storage Ring

survey, storage-ring, sextupole, insertion

1674

M. Apollonio, R. Bartolini, R.T. Fielder, W.J. Hoffman, J. Kay, I.P.S. Martin, B. Singh
Diamond, Oxfordshire, United Kingdom

Using a model of the Diamond storage ring which includes displacements and rotations of the 74 magnet girders an attempt has been made to correlate survey data with the corrector magnet (CM) strengths required for a zero orbit. We then use the model to deduce the most effective girder movements that will bring about a reduction in corrector strength. We describe the results of these studies, and suggest a test with a deliberately displaced girder and the effect on corrector strengths, aimed at enhancing our understanding of the system

WEPPP084

Weighted SVD Algorithm for Close-Orbit Correction and 10 Hz Feedback in RHIC

feedback, electron, proton, ion

2906

C. Liu, R.L. Hulsart, A. Marusic, R.J. Michnoff, M.G. Minty, V. Ptitsyn
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Measurements of the beam position along an accelerator are typically treated equally using standard SVD-based orbit correction algorithms so distributing the residual errors, modulo the local beta function, equally at the measurement locations. However, sometimes a more stable orbit at select locations is desirable. In this paper, we introduce an algorithm for weighting the beam position measurements to achieve a more stable local orbit. The results of its application to close-orbit correction and 10-Hz orbit feedback will be shown and analyzed.

WEPPR006

Serpentine Acceleration in Scaling FFAG

acceleration, proton, injection, betatron

2946

E. Yamakawa, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan
K. Okabe, I. Sakai
University of Fukui, Faculty of Engineering, Fukui, Japan

A serpentine acceleration in scaling FFAG accelerator is examined. In this scheme, high-energy and high-current beam can be obtained in non-relativistic energy region. Longitudinal hamiltonian is derived analytically. Experiment to demonstrate a serpentine acceleration in scaling FFAG is done.

THPPR064

MW-class 800 MeV/n H²⁺ SC-Cyclotron for ADC application, Design Study and Goals

cyclotron, extraction, injection, target

4121

F. Méot, T. Roser, W.-T. Weng
BNL, Upton, Long Island, New York, USA
L. Calabretta
INFN/LNS, Catania, Italy
A. Calanna
CSFNSM, Catania, Italy

A megawatt class isochronous cyclotron is a potential candidate for accelerator driven systems, as in the subcritical-fission molten-salt reactor application. A scheme for a 800 MeV/nucleon cyclotron accelerating molecular H₂⁺ has been derived from on-going proton driver design studies for neutrino beam production. The present paper reports on beam dynamics studies regarding that cyclotron, exploiting its superconducting coil magnetic sector OPERA field map. These studies are aimed at assessing lattice properties as accelerated orbit, phase oscillations, tunes, beam envelopes and other resonance effects.