HB2016 - List of Keywords (lattice)

Paper	Title	Other Keywords	Page
MOPR027	Dynamic Beta and Beta-Beating Effects in the Presence of the Beam-Beam Interactions	optics, quadrupole, collider, luminosity	136
	T. Pieloni, X. Buffat, L.E. Medina Medrano, C. Tambasco, R. Tomás CERN, Geneva, Switzerland J. Barranco, P. Concalves Jorge, C. Tambasco EPFL, Lausanne, Switzerland
	The Large Hadron Collider (LHC) has achieved correction of beta beat down to better than 5%. The beam-beam interactions at the four experiments result as extra quadrupole error in the lattice. This will produce a change of the β^* at the experiments and a beating along the arcs which for the High Luminosity LHC (HL-LHC) will be very large. Estimations of these effects will be given with the characterisation of the amplitude dependency. A first attempt to correct his beating is also discussed.
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MOPR030	Simple Models for Beam Loss Near the Half Integer Resonance with Space Charge	resonance, space-charge, simulation, coherent-effects	150
	C.M. Warsop, D.J. Adams, B. Jones, B.G. Pine STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The half integer resonance is often used to define the high intensity limit of medium or low energy hadron rings where transverse space charge is significant. However, the mechanism leading to particle loss as beam approaches this resonance, which thus defines the limit, is not clearly understood. In this paper we explore simple models, based on single particle resonance ideas, to see if they describe useful aspects of motion as observed in simulations and experiments of 2D coasting beams on the ISIS synchrotron. Single particle behaviour is compared to 2D self-consistent models to assess when coherent motion begins to affect the single particle motion, and understand the relevance of coherent and incoherent resonance. Whilst the general problem of 2D resonant loss, with non-stationary distributions and non-linear fields is potentially extremely complicated, here we suggest that for a well-designed machine, where higher order pathological loss effects are avoided, a relatively simple model may give valuable insights into beam behaviour and control.
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MOPR034	Suppression of Half-Integer Resonance in Fermilab Booster	space-charge, booster, resonance, optics	164
	V.A. Lebedev, A. Valishev Fermilab, Batavia, Illinois, USA
	The particle losses at injection in the FNAL Booster are one of the major factors limiting the machine performance. The losses are caused by motion non-linearity due to direct space charge and due to non-linearity introduced by large values of chromaticity sextupoles required to suppress transverse instabilities. The report aims to address the former - the suppression of incoherent space charge effects by reducing deviations from the perfect periodicity of linear optics functions. It should be achieved by high accuracy optics measurements with subsequent optics correction and by removing known sources of optics perturbations. The study shows significant impact of optics correction on the half-integer stop band with subsequent reduction of particle loss. We use realistic Booster lattice model to understand the present limitations, and investigate the possible improvements which would allow high intensity operation with PIP-II parameters.
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MOPR036	Spin Tracking of Polarized Protons in the Main Injector at Fermilab	polarization, closed-orbit, resonance, proton	173
	M. Xiao Fermilab, Batavia, Illinois, USA C. Aldred, W. Lorenzon Michigan University, Ann Arbor, Michigan, USA
	The Main Injector (MI) at Fermilab currently produces high-intensity beams of protons at energies of 120 GeV for a variety of physics experiments. Acceleration of polarized protons in the MI would provide opportunities for a rich spin physics program at Fermilab. To achieve polarized proton beams in the Fermilab accelerator com-plex, shown in Fig.1.1, detailed spin tracking simulations with realistic parameters based on the existing facility are required. This report presents studies at the MI using a single 4-twist Siberian snake to determine the depolariz-ing spin resonances for the relevant synchrotrons. Results will be presented first for a perfect MI lattice, followed by a lattice that includes the real MI imperfections, such as the measured magnet field errors and quadrupole misa-lignments. The tolerances of each of these factors in maintaining polarization in the Main Injector will be discussed.
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MOPL006	Beam Dynamics Study of C-Ads Injector-I With Developing P-Topo Code	rfq, simulation, space-charge, emittance	195
	Zh.C. Liu, C. Li, Q. Qin, F. Yan, Y.L. Zhao IHEP, Beijing, People's Republic of China
	A parallelized, time-dependent 3D particle simulation code is under developing to study the high-intensity beam dynamics in linear accelerators. The self-consistent space charge effect is taken into account with the Particle-In-Cell (PIC) method. In this paper, the structure of program and the parallel strategy are demonstrated. Then, we show the results of code verification and benchmarking. It is proved that the solvers in P-TOPO code and parallel strategy are reliable and efficient. Finally, the beam dynamics simulation of C-ADS Injector-I at IHEP are launched with P-TOPO and other codes. The possible reasons for the differences between results given by separated codes are also proposed.
	Poster MOPL006 [2.169 MB]
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MOPL007	Beam Steering Studies for the Superconducting Linac of the RAON Accelerator	quadrupole, linac, GUI, simulation	199
	H. Jin, J.-H. Jang, D. Jeon IBS, Daejeon, Republic of Korea
	The RAON accelerator of Rare Isotope Science Project (RISP) has been developed to accelerate various kinds of stable ion beams and rare isotope beams for a wide range of science experiments. In the RAON accelerator, the superconducting linac (SCL) will be installed for the acceleration of the beams and it is composed of tens of cryomodules which include superconducting radio frequency cavities. Between two cryomodules, there is a warm section and two quadrupoles are located in the warm section with a beam diagnostics box in between. Also, in this warm section, one horizontal corrector and one beam position monitor (BPM) are mounted inside of first quadrupole, and one vertical corrector is located inside of second quadrupole for the beam steering. With these correctors and BPMs, the beam steering studies are carried out as varying the number of correctors and BPMs in the SCL of the RAON accelerator and the results are presented.
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MOPL024	Study of Magnets Sorting of the CSNS/RCS Dipoles and Quadrupoles*	dipole, quadrupole, closed-orbit, injection	247
	Y.W. An, H.F. Ji, Y. Li, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China J. Peng CSNS, Guangdong Province, People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China (11405189)* The Rapid Cycling Synchrotron plays an important role in the China Spallation Neutron Source. RCS accumulates and accelerates the proton beams from 80MeV to 1.6GeV for striking the target with the repetition rate of 25Hz. RCS demands low uncontrolled loss for hands on maintenance, and one needs a tight tolerance on magnet field accuracy. Magnet sorting can be done to minimize linear effects of beam dynamics. Using closed-orbit distortion (COD) and beta-beating independently as the merit function, and considering maintaining the symmetry of the lattice, a code based on traversal algorithm is developed to get the dipoles and quadrupoles sorting for CSNS/RCS. The comparison of beam distribution, collimation efficiency and beam loss are also investigated according to beam injection and beam accelerating.
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TUAM3Y01	Beam Dynamics Challenges in the ESS Linac	linac, rfq, cryomodule, DTL	315
	Y.I. Levinsen, R. De Prisco, M. Eshraqi, R. Miyamoto, M. Muñoz, A. Ponton ESS, Lund, Sweden
	The European Spallation Source will be the worlds brightest neutron source. It will be driven by a 5~MW proton linac that delivers a 2.86~ms pulse at 14~Hz, which means the peak beam power is 125~MW. This requires a careful design of the lattice structures in order to allow for safe and reliable operation of the accelerator. We will discuss some of the design choices and some of the particular challenges that were faced during the design of the ESS lattice.
	Slides TUAM3Y01 [4.203 MB]
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WEAM6X01	Studies of High Intensity Proton FFAGs at RAL	injection, proton, linac, emittance	379
	C.R. Prior STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The paper describes studies of high intensity proton accelerators for a next-generation source of short-pulse spallation neutrons. Along with conventional designs using rapid cycling synchrotrons, the long-term nature of the project provides scope for novel accelerator designs and developing technological ideas. A range of FFAG options is under consideration for the main spallation driver. Theory and simulation in the UK are combined with experimental studies of FFAGs in Japan, and a small prototype FFAG ring is planned to go on the FETS injector at RAL for essential R&D. The paper covers the broad scope of the programme and details the success of the study to date.
	Slides WEAM6X01 [12.105 MB]
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WEPM2Y01	Model Benchmark With Experiment at the SNS Linac	cavity, linac, laser, space-charge	439
	A.P. Shishlo, A.V. Aleksandrov, M.A. Plum ORNL, Oak Ridge, Tennessee, USA Y. Liu ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. The history of attempts to perform a transverse matching in the SNS superconducting linac (SCL) is discussed. The SCL has 9 laser wire (LW) stations to perform nondestructive measurements of the transverse beam profiles. Any matching starts with the measurement of the initial Twiss parameters which in the SNS case was done by using the first four LW stations at the beginning of the superconducting linac. For years the consistency between all LW stations data could not be achieved. This problem was resolved only after significant improvements in accuracy of the phase scans of the SCL cavities, more precise analysis of all available scan data, better optics planning, and the initial longitudinal Twiss parameters measurements. The presented paper discusses in details these developed procedures.
	Slides WEPM2Y01 [2.815 MB]
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THPM1X01	Typology of Space Charge Resonances	resonance, space-charge, emittance, focusing	486
	I. Hofmann GSI, Darmstadt, Germany
	The existence of structural space charge resonant effects in otherwise linear periodic focusing systems is well-known, but referred to in a variety of languages and contexts. We show here that for short bunched beams a ‘‘classification'' in two major groups is possible, e.g. parametric resonances or instabilities on the one hand and single particle type space charge resonances on the other hand. The primary feature of distinction is that for the former the driving space charge force initially exists on the noise level (rms or higher order mismatch) only and gets amplified parametrically, hence an entirely coherent response; for the latter the driving space charge multipole is part of the initial density profile and the coherent response is weak. In the extreme limit of KV beams only parametric resonances (instabilities) exist, and in principle in all orders. For waterbag or Gaussian distributions we find half-integer parametric resonances only up to fourth order, but evidence for single particle resonances in all orders up to tenth have been identified.
	Slides THPM1X01 [3.094 MB]
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THPM4X01	Resonances and Envelope Instability in High Intensity Linear Accelerators	resonance, space-charge, linac, emittance	491
	D. Jeon, J.-H. Jang, H. Jin IBS, Daejeon, Republic of Korea
	Funding: This work was supported by the Institute for Basic Science funded by the Ministry of Science, ICT and Future Planning (MSIP) and the NRF of Korea under Contract 2013M7A1A1075764. Understanding of space charge effects has grown and recent studies have led to the findings of resonances of high intensity linear accelerators. Lately the sixth order resonance of high intensity linear accelerators was reported, along with the in-depth studies on the fourth order resonance and the envelope instability. Experiment studies on space charge resonances were reported. This paper reviews the resonances of high intensity linear accelerators such as the 4σ =360deg, and the 6σ =720deg resonances, along with the envelope instability.
	Slides THPM4X01 [3.279 MB]
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THPM6X01	Space Charge Effects in FFAG	space-charge, closed-orbit, betatron, emittance	499
	M. Haj Tahar, F. Méot 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. Understanding space charge effects in FFAG is crucial in order to assess their potential for high power applications. This paper shows that, to carry out parametric studies of these effects in FFAG, the average field index of the focusing and defocusing magnets are the natural parametrization. Using several classes of particle distribution functions, we investigate the effects of space charge forces on the non-linear beam dynamics of FFAG and provide stability diagrams for an FFAG-like lattice. The method developed in this study is mainly applicable to systems with slowly varying parameters, i.e slow acceleration.
	Slides THPM6X01 [2.171 MB]
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THPM8X01	Early Tests and Simulation of Quasi-Integrable Octupole Lattices at the University of Maryland Electron Ring	octupole, distributed, quadrupole, simulation	511
	K.J. Ruisard, H. Baumgartner, B. Beaudoin, I. Haber, T.W. Koeth, D.B. Matthew UMD, College Park, Maryland, USA
	Funding: Work and travel supported by NSF GRFP, NSF Accelerator Science Program, DOE-HEP and UMD Graduate School ICSSA award. Nonlinear quasi-integrable optics is a promising development on the horizon of high-intensity ring design. Large amplitude-dependent tune spreads, driven by strong nonlinear magnet inserts, lead to decoherence from incoherent tune resonances. This reduces intensity-driven beam loss while quasi-integrability ensures contained orbits. The experimental program at the University of Maryland Electron Ring (UMER) will explore the performance of a strong octupole lattice at a range of operating points. Early measurements use a distributed octupole lattice, consisting of several small octupole inserts. We vary lattice tune to change the quasi-integrable condition as well as probe behavior near different resonant conditions. Simulation results show there should be invariant conservation under carefully chosen conditions. We discuss the effect of steering errors on the lattice performance and on-going efforts to reduce these errors. We also discuss plans for a single-channel insert.
	Slides THPM8X01 [56.742 MB]
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Paper

Title

Other Keywords

Page

MOPR027

Dynamic Beta and Beta-Beating Effects in the Presence of the Beam-Beam Interactions

optics, quadrupole, collider, luminosity

136

T. Pieloni, X. Buffat, L.E. Medina Medrano, C. Tambasco, R. Tomás
CERN, Geneva, Switzerland
J. Barranco, P. Concalves Jorge, C. Tambasco
EPFL, Lausanne, Switzerland

The Large Hadron Collider (LHC) has achieved correction of beta beat down to better than 5%. The beam-beam interactions at the four experiments result as extra quadrupole error in the lattice. This will produce a change of the β^* at the experiments and a beating along the arcs which for the High Luminosity LHC (HL-LHC) will be very large. Estimations of these effects will be given with the characterisation of the amplitude dependency. A first attempt to correct his beating is also discussed.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPR030

Simple Models for Beam Loss Near the Half Integer Resonance with Space Charge

resonance, space-charge, simulation, coherent-effects

150

C.M. Warsop, D.J. Adams, B. Jones, B.G. Pine
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The half integer resonance is often used to define the high intensity limit of medium or low energy hadron rings where transverse space charge is significant. However, the mechanism leading to particle loss as beam approaches this resonance, which thus defines the limit, is not clearly understood. In this paper we explore simple models, based on single particle resonance ideas, to see if they describe useful aspects of motion as observed in simulations and experiments of 2D coasting beams on the ISIS synchrotron. Single particle behaviour is compared to 2D self-consistent models to assess when coherent motion begins to affect the single particle motion, and understand the relevance of coherent and incoherent resonance. Whilst the general problem of 2D resonant loss, with non-stationary distributions and non-linear fields is potentially extremely complicated, here we suggest that for a well-designed machine, where higher order pathological loss effects are avoided, a relatively simple model may give valuable insights into beam behaviour and control.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPR034

Suppression of Half-Integer Resonance in Fermilab Booster

space-charge, booster, resonance, optics

164

V.A. Lebedev, A. Valishev
Fermilab, Batavia, Illinois, USA

The particle losses at injection in the FNAL Booster are one of the major factors limiting the machine performance. The losses are caused by motion non-linearity due to direct space charge and due to non-linearity introduced by large values of chromaticity sextupoles required to suppress transverse instabilities. The report aims to address the former - the suppression of incoherent space charge effects by reducing deviations from the perfect periodicity of linear optics functions. It should be achieved by high accuracy optics measurements with subsequent optics correction and by removing known sources of optics perturbations. The study shows significant impact of optics correction on the half-integer stop band with subsequent reduction of particle loss. We use realistic Booster lattice model to understand the present limitations, and investigate the possible improvements which would allow high intensity operation with PIP-II parameters.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPR036

Spin Tracking of Polarized Protons in the Main Injector at Fermilab

polarization, closed-orbit, resonance, proton

173

M. Xiao
Fermilab, Batavia, Illinois, USA
C. Aldred, W. Lorenzon
Michigan University, Ann Arbor, Michigan, USA

The Main Injector (MI) at Fermilab currently produces high-intensity beams of protons at energies of 120 GeV for a variety of physics experiments. Acceleration of polarized protons in the MI would provide opportunities for a rich spin physics program at Fermilab. To achieve polarized proton beams in the Fermilab accelerator com-plex, shown in Fig.1.1, detailed spin tracking simulations with realistic parameters based on the existing facility are required. This report presents studies at the MI using a single 4-twist Siberian snake to determine the depolariz-ing spin resonances for the relevant synchrotrons. Results will be presented first for a perfect MI lattice, followed by a lattice that includes the real MI imperfections, such as the measured magnet field errors and quadrupole misa-lignments. The tolerances of each of these factors in maintaining polarization in the Main Injector will be discussed.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPL006

Beam Dynamics Study of C-Ads Injector-I With Developing P-Topo Code

rfq, simulation, space-charge, emittance

195

Zh.C. Liu, C. Li, Q. Qin, F. Yan, Y.L. Zhao
IHEP, Beijing, People's Republic of China

A parallelized, time-dependent 3D particle simulation code is under developing to study the high-intensity beam dynamics in linear accelerators. The self-consistent space charge effect is taken into account with the Particle-In-Cell (PIC) method. In this paper, the structure of program and the parallel strategy are demonstrated. Then, we show the results of code verification and benchmarking. It is proved that the solvers in P-TOPO code and parallel strategy are reliable and efficient. Finally, the beam dynamics simulation of C-ADS Injector-I at IHEP are launched with P-TOPO and other codes. The possible reasons for the differences between results given by separated codes are also proposed.

Poster MOPL006 [2.169 MB]

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MOPL007

Beam Steering Studies for the Superconducting Linac of the RAON Accelerator

quadrupole, linac, GUI, simulation

199

H. Jin, J.-H. Jang, D. Jeon
IBS, Daejeon, Republic of Korea

The RAON accelerator of Rare Isotope Science Project (RISP) has been developed to accelerate various kinds of stable ion beams and rare isotope beams for a wide range of science experiments. In the RAON accelerator, the superconducting linac (SCL) will be installed for the acceleration of the beams and it is composed of tens of cryomodules which include superconducting radio frequency cavities. Between two cryomodules, there is a warm section and two quadrupoles are located in the warm section with a beam diagnostics box in between. Also, in this warm section, one horizontal corrector and one beam position monitor (BPM) are mounted inside of first quadrupole, and one vertical corrector is located inside of second quadrupole for the beam steering. With these correctors and BPMs, the beam steering studies are carried out as varying the number of correctors and BPMs in the SCL of the RAON accelerator and the results are presented.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPL024

Study of Magnets Sorting of the CSNS/RCS Dipoles and Quadrupoles*

dipole, quadrupole, closed-orbit, injection

247

Y.W. An, H.F. Ji, Y. Li, S. Wang, S.Y. Xu
IHEP, Beijing, People's Republic of China
J. Peng
CSNS, Guangdong Province, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China (11405189)*
The Rapid Cycling Synchrotron plays an important role in the China Spallation Neutron Source. RCS accumulates and accelerates the proton beams from 80MeV to 1.6GeV for striking the target with the repetition rate of 25Hz. RCS demands low uncontrolled loss for hands on maintenance, and one needs a tight tolerance on magnet field accuracy. Magnet sorting can be done to minimize linear effects of beam dynamics. Using closed-orbit distortion (COD) and beta-beating independently as the merit function, and considering maintaining the symmetry of the lattice, a code based on traversal algorithm is developed to get the dipoles and quadrupoles sorting for CSNS/RCS. The comparison of beam distribution, collimation efficiency and beam loss are also investigated according to beam injection and beam accelerating.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUAM3Y01

Beam Dynamics Challenges in the ESS Linac

linac, rfq, cryomodule, DTL

315

Y.I. Levinsen, R. De Prisco, M. Eshraqi, R. Miyamoto, M. Muñoz, A. Ponton
ESS, Lund, Sweden

The European Spallation Source will be the worlds brightest neutron source. It will be driven by a 5~MW proton linac that delivers a 2.86~ms pulse at 14~Hz, which means the peak beam power is 125~MW. This requires a careful design of the lattice structures in order to allow for safe and reliable operation of the accelerator. We will discuss some of the design choices and some of the particular challenges that were faced during the design of the ESS lattice.

Slides TUAM3Y01 [4.203 MB]

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEAM6X01

Studies of High Intensity Proton FFAGs at RAL

injection, proton, linac, emittance

379

C.R. Prior
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The paper describes studies of high intensity proton accelerators for a next-generation source of short-pulse spallation neutrons. Along with conventional designs using rapid cycling synchrotrons, the long-term nature of the project provides scope for novel accelerator designs and developing technological ideas. A range of FFAG options is under consideration for the main spallation driver. Theory and simulation in the UK are combined with experimental studies of FFAGs in Japan, and a small prototype FFAG ring is planned to go on the FETS injector at RAL for essential R&D. The paper covers the broad scope of the programme and details the success of the study to date.

Slides WEAM6X01 [12.105 MB]

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WEPM2Y01

Model Benchmark With Experiment at the SNS Linac

cavity, linac, laser, space-charge

439

A.P. Shishlo, A.V. Aleksandrov, M.A. Plum
ORNL, Oak Ridge, Tennessee, USA
Y. Liu
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
The history of attempts to perform a transverse matching in the SNS superconducting linac (SCL) is discussed. The SCL has 9 laser wire (LW) stations to perform nondestructive measurements of the transverse beam profiles. Any matching starts with the measurement of the initial Twiss parameters which in the SNS case was done by using the first four LW stations at the beginning of the superconducting linac. For years the consistency between all LW stations data could not be achieved. This problem was resolved only after significant improvements in accuracy of the phase scans of the SCL cavities, more precise analysis of all available scan data, better optics planning, and the initial longitudinal Twiss parameters measurements. The presented paper discusses in details these developed procedures.

Slides WEPM2Y01 [2.815 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPM1X01

Typology of Space Charge Resonances

resonance, space-charge, emittance, focusing

486

I. Hofmann
GSI, Darmstadt, Germany

The existence of structural space charge resonant effects in otherwise linear periodic focusing systems is well-known, but referred to in a variety of languages and contexts. We show here that for short bunched beams a ‘‘classification'' in two major groups is possible, e.g. parametric resonances or instabilities on the one hand and single particle type space charge resonances on the other hand. The primary feature of distinction is that for the former the driving space charge force initially exists on the noise level (rms or higher order mismatch) only and gets amplified parametrically, hence an entirely coherent response; for the latter the driving space charge multipole is part of the initial density profile and the coherent response is weak. In the extreme limit of KV beams only parametric resonances (instabilities) exist, and in principle in all orders. For waterbag or Gaussian distributions we find half-integer parametric resonances only up to fourth order, but evidence for single particle resonances in all orders up to tenth have been identified.

Slides THPM1X01 [3.094 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPM4X01

Resonances and Envelope Instability in High Intensity Linear Accelerators

resonance, space-charge, linac, emittance

491

D. Jeon, J.-H. Jang, H. Jin
IBS, Daejeon, Republic of Korea

Funding: This work was supported by the Institute for Basic Science funded by the Ministry of Science, ICT and Future Planning (MSIP) and the NRF of Korea under Contract 2013M7A1A1075764.
Understanding of space charge effects has grown and recent studies have led to the findings of resonances of high intensity linear accelerators. Lately the sixth order resonance of high intensity linear accelerators was reported, along with the in-depth studies on the fourth order resonance and the envelope instability. Experiment studies on space charge resonances were reported. This paper reviews the resonances of high intensity linear accelerators such as the 4σ =360deg, and the 6σ =720deg resonances, along with the envelope instability.

Slides THPM4X01 [3.279 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPM6X01

Space Charge Effects in FFAG

space-charge, closed-orbit, betatron, emittance

499

M. Haj Tahar, F. Méot
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.
Understanding space charge effects in FFAG is crucial in order to assess their potential for high power applications. This paper shows that, to carry out parametric studies of these effects in FFAG, the average field index of the focusing and defocusing magnets are the natural parametrization. Using several classes of particle distribution functions, we investigate the effects of space charge forces on the non-linear beam dynamics of FFAG and provide stability diagrams for an FFAG-like lattice. The method developed in this study is mainly applicable to systems with slowly varying parameters, i.e slow acceleration.

Slides THPM6X01 [2.171 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPM8X01

Early Tests and Simulation of Quasi-Integrable Octupole Lattices at the University of Maryland Electron Ring

octupole, distributed, quadrupole, simulation

511

K.J. Ruisard, H. Baumgartner, B. Beaudoin, I. Haber, T.W. Koeth, D.B. Matthew
UMD, College Park, Maryland, USA

Funding: Work and travel supported by NSF GRFP, NSF Accelerator Science Program, DOE-HEP and UMD Graduate School ICSSA award.
Nonlinear quasi-integrable optics is a promising development on the horizon of high-intensity ring design. Large amplitude-dependent tune spreads, driven by strong nonlinear magnet inserts, lead to decoherence from incoherent tune resonances. This reduces intensity-driven beam loss while quasi-integrability ensures contained orbits. The experimental program at the University of Maryland Electron Ring (UMER) will explore the performance of a strong octupole lattice at a range of operating points. Early measurements use a distributed octupole lattice, consisting of several small octupole inserts. We vary lattice tune to change the quasi-integrable condition as well as probe behavior near different resonant conditions. Simulation results show there should be invariant conservation under carefully chosen conditions. We discuss the effect of steering errors on the lattice performance and on-going efforts to reduce these errors. We also discuss plans for a single-channel insert.

Slides THPM8X01 [56.742 MB]

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