LINAC2012 - List of Keywords (quadrupole)

Paper	Title	Other Keywords	Page
SUPB012	Status of CH Cavity and Solenoid Design of the 17 MeV Injector for MYRRHA	solenoid, cavity, focusing, rfq	29
	D. Mäder, H. Klein, H. Podlech, U. Ratzinger, C. Zhang IAP, Frankfurt am Main, Germany
	Funding: This work has been supported by the EU (FP7 MAX contract number 269565) The multifunctional subcritical reactor MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) will be an accelerator driven system (ADS) located in Mol (Belgium). The first accelerating section up to 17 MeV is operated at 176 MHz and consists of a 4-rod-RFQ followed by two room temperature CH cavities with integrated triplet lenses and four superconducting CH structures with intertank solenoids. Each room temperature CH cavity provides about 1 MV effective voltage gain using less than 30 kW of RF power. The superconducting resonators have been optimized for electric peak fields below 30 MV/m and magnetic peak fields below 30 mT. For save operation of the superconducting resonators the magnetic field of the intertank solenoids has to be well shielded towards the CH cavity walls. Different coil geometries have been compared to find the ideal solenoid layout.

MO2A02	Increased Understanding of Beam Losses from the SNS Linac Proton Experiment	proton, linac, focusing, optics	115
	J. Galambos, A.V. Aleksandrov, M.A. Plum, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA E. Laface ESS, Lund, Sweden V.A. Lebedev Fermilab, Batavia, USA
	The SNS Linac has been in operation for 6 years, with its power being gradually increased. A major operation goal is the decrease of beam loss. It has been recently suggested that intra- H–beam stripping contributes significantly to beam losses in an H⁻ linac. This was tested experimentally at SNS by accelerating a proton beam. Experimental analysis results are in good agreement with the theoretical estimates. In this paper we present the operational status and experience at the SNS linac, with emphasis on understanding beam loss in terms of intra-H–beam stripping.
	Slides MO2A02 [12.869 MB]

MOPLB01	Emittance Control for Different FACET Beam Setups in the SLAC Linac	linac, emittance, klystron, wakefield	138
	F.-J. Decker, W.S. Colocho, N. Lipkowitz, Y. Nosochkov, J. Sheppard, H. Smith, Y. Sun, M.-H. Wang, G.R. White, U. Wienands, M. Woodley, G. Yocky SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515. The linac beam at SLAC requires different setups for different users at FACET (Facility for Advanced aCcelerator Experimental Tests) area, like highly compressed, intense bunches, or lower charge, long bunches. These require typically a lengthy tuning effort since with a energy-time correlation ("chirp") bunch transverse wakefield kicks can be compensated with dispersive trajectory oscillations and vice versa. Lowering the charge or changing the bunch length will destroy this delicate balance. Besides the typical steering to minimize BPMs (Beam Position Monitors) with correctors, we applied different techniques to try to localize beam disturbances like dispersion with phase changes, RF-kicks and RF quadrupole fields turning a klystron off and on, or varying the phase, and finally wakefield kicks with different beam intensities. It is also important to quantify BPM to quadrupole offsets with "bow-tie" plot and that the correctors give the expected kicks with orbit response matrix measurements.
	Slides MOPLB01 [0.826 MB]

MOPLB02	Positron Injector Linac Upgrade for SuperKEKB	positron, electron, linac, target	141
	T. Kamitani, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, K. Furukawa, Y. Higashi, T. Higo, H. Honma, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	The KEKB B-factory is under an upgrade construction for the SuperKEKB. To achieve 40 times higher luminosity, the linac is required to inject electrons and positrons with higher intensities (e^-: 1 nC → 5 nC, e⁺: 1 nC → 4 nC) and lower emittances (e^-: 300 → 20 μm, e⁺: 2100 → 10 μm). This paper describes the upgrade scheme of the positron source. A new positron capture section will have larger transverse and energy acceptances by introducing a flux concentrator and large aperture L-band and S-band accelerating structures. Beam line layout and quadrupole focusing system will be rearranged for the enlarged beam acceptance. Beam optics is designed to be compatible for positron and electron beams with different energies and emittances. Pulsed quadrupoles and steering magnets are added for better flexibility in optics and orbit tuning. Parameter optimization of the positron source by optics calculation and particle tracking simulation is described.
	Slides MOPLB02 [0.575 MB]

MOPB001	Emittance Control for Different FACET Beam Setups in the SLAC Linac	linac, emittance, klystron, wakefield	174
	F.-J. Decker, W.S. Colocho, N. Lipkowitz, Y. Nosochkov, J. Sheppard, H. Smith, Y. Sun, M.-H. Wang, G.R. White, U. Wienands, M. Woodley, G. Yocky SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515. The linac beam at SLAC requires different setups for different users at FACET (Facility for Advanced aCcelerator Experimental Tests) area, like highly compressed, intense bunches, or lower charge, long bunches. These require typically a lengthy tuning effort since with a energy-time correlation ("chirp") bunch transverse wakefield kicks can be compensated with dispersive trajectory oscillations and vice versa. Lowering the charge or changing the bunch length will destroy this delicate balance. Besides the typical steering to minimize BPMs (Beam Position Monitors) with correctors, we applied different techniques to try to localize beam disturbances like dispersion with phase changes, RF-kicks and RF quadrupole fields turning a klystron off and on, or varying the phase, and finally wakefield kicks with different beam intensities. It is also important to quantify BPM to quadrupole offsets with "bow-tie" plot and that the correctors give the expected kicks with orbit response matrix measurements.

MOPB002	Positron Injector Linac Upgrade for SuperKEKB	positron, electron, linac, target	177
	T. Kamitani, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, K. Furukawa, Y. Higashi, T. Higo, H. Honma, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	The KEKB B-factory is under an upgrade construction for the SuperKEKB. To achieve 40 times higher luminosity, the linac is required to inject electrons and positrons with higher intensities (e^-: 1 nC → 5 nC, e⁺: 1 nC → 4 nC) and lower emittances (e^-: 300 → 20 μm, e⁺: 2100 → 10 μm). This paper describes the upgrade scheme of the positron source. A new positron capture section will have larger transverse and energy acceptances by introducing a flux concentrator and large aperture L-band and S-band accelerating structures. Beam line layout and quadrupole focusing system will be rearranged for the enlarged beam acceptance. Beam optics is designed to be compatible for positron and electron beams with different energies and emittances. Pulsed quadrupoles and steering magnets are added for better flexibility in optics and orbit tuning. Parameter optimization of the positron source by optics calculation and particle tracking simulation is described.

MOPB014	Electron Model of a Dogbone RLA with Multi-Pass Arcs	linac, electron, dipole, optics	201
	S.A. Bogacz, G.A. Krafft, V.S. Morozov, Y. Roblin JLAB, Newport News, Virginia, USA K.B. Beard Muons. Inc., USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by USDOE STTR Grant DE-FG02-08ER86351 The design of a dogbone RLA with linear-field multi-pass arcs was earlier developed for accelerating muons in a Neutrino Factory and a Muon Collider. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over separate-arc or pulsed-arc designs. Such an RLA may have applications going beyond muon acceleration. This paper describes a possible straightforward test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme, in which a 4.35 MeV/c electron beam is injected in the middle of a 2.9 MeV/pass linac with two double-pass return arcs and is accelerated to 17.4 MeV/c in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to a readily available 1.5 GHz. The footprint of a complete RLA fits in a 25x7 m area. The scheme utilizes only fixed field magnets for both injection and extraction. The hardware requirements are not very demanding making it straightforward to implement the scaled design using available equipment.

MOPB067	Results and Performance Simulations of the Main Linac Design for BERLinPro	cavity, HOM, linac, dipole	333
	A. Neumann, W. Anders, J. Knobloch HZB, Berlin, Germany K. Brackebusch, T. Flisgen, T. Galek, K. Papke, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany B. Riemann, T. Weis DELTA, Dortmund, Germany
	Funding: this work is partly funded by BMBF contract no. 05K10PEA and 05K10HRC The Berlin Energy Recovery Linac Project (BERLinPro) is designed to develop and demonstrate CW LINAC technology for 100-mA-class ERLs. High-current operation requires an effective damping of higher-order modes (HOMs) of the 1.3 GHz main-linac cavities. We have studied elliptical 7-cell cavities damped by on the whole five waveguides at both ends. Eigenmode computations for geometrical figures of merit show that the present design should allow successful CW linac operation at the maximum beam current of 100 mA/77 pC bunch charge. To verify the results, the external Q factors are compared to the results of S-Parameter simulations that are postprocessed by a pole-fitting technique. First results of scattering parameter measurement on a room-temperature aluminium model are discussed. An outlook presenting the possibilities of combined multi-cavity simulations is included.

MOPB072	Multipole Expansion of the Fields in Superconducting High-Velocity Spoke Cavities	cavity, multipole, linac, simulation	345
	R.G. Olave, J.R. Delayen, C.S. Hopper ODU, Norfolk, Virginia, USA
	Multi-spokes superconducting cavities in the high-beta regime are being considered for a number of applications. In order to accurately model the dynamics of the particles in such cavities, knowledge of the fields off-axis are needed. We present a study of the multipoles expansion of the fields from an EM simulation field data for a two-spoke cavity operating at 325 MHz, β = 0.82 and 500 MHz, β = 1.

MOPB095	Design of MEBT for the Project X Injector Experiment at Fermilab	kicker, vacuum, SRF, diagnostics	398
	A.V. Shemyakin, C.M. Baffes, A.Z. Chen, Y.I. Eidelman, B.M. Hanna, V.A. Lebedev, S. Nagaitsev, J.-F. Ostiguy, R.J. Pasquinelli, D.W. Peterson, L.R. Prost, G.W. Saewert, V.E. Scarpine, B.G. Shteynas, N. Solyak, D. Sun, M. Wendt, V.P. Yakovlev Fermilab, Batavia, USA T. Tang SLAC, Menlo Park, California, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE The Project X Injector Experiment (PXIE), a test bed for the Project X front end, will be completed at Fermilab at FY12-16. One of the challenging goals of PXIE is demonstration of the capability to form a 1 mA H⁻ beam with an arbitrary selected bunch pattern from the initially 5 mA 162.5 MHz CW train. The bunch selection will be made in the Medium Energy Beam Transport (MEBT) at 2.1 MeV by diverting undesired bunches to an absorber. This paper will present the MEBT scheme and describe development of its elements, including the kickers and absorber.

MOPB098	Planning for Experimental Demonstration of Transverse Emittance Transfer at the GSI UNILAC through Eigen-Emittance Shaping	emittance, coupling, simulation, scattering	404
	C. Xiao, O.K. Kester IAP, Frankfurt am Main, Germany L. Groening GSI, Darmstadt, Germany
	The minimum transverse emittances achievable in a beam line are determined by the two transverse eigen-emittances of the beam. For vanishing interplane correlations they are equal to the transverse rms-emittances. Eigen-emittances are constants of motion for all symplectic beam line elements, i.e. (even tilted) linear elements. To allow for rms-emittance transfer, the eigen-emittances are changed by a non-symplectic action to the beam, preferably preserving the 4d-rms-emittance. Unlike emittance swapping the presented concept will allow transforming a beam of equal rms-emittances into a beam of different rms-emittances while preserving the 4d-rms-emittance. This contribution will introduce the concept for eigen-emittance shaping and rms-emittance transfer at an ion linac. The actual work status towards the experimental demonstration of the concept at the GSI UNILAC is presented.

TUPB013	Update on the Commissioning Effort at the SwissFEL Injector Test Facility	emittance, laser, electron, optics	504
	T. Schietinger PSI, Villigen, Switzerland
	The SwissFEL Injector Test Facility at the Paul Scherrer Institute is the principal test bed and demonstration plant for the SwissFEL project, which aims at realizing a hard-X-ray Free Electron Laser by 2017. Since the spring of 2012 the photoinjector facility has been running with all RF cavities in full operation, allowing beam characterization at energies around 230 MeV with bunch charges between 10 and 200 pC. We give an overview of recent commissioning efforts with particular emphasis on efforts to optimize the emittance of the uncompressed beam.

TUPB058	An Analytical Cavity Model for Fast Linac-Beam Tuning	multipole, cavity, dipole, simulation	609
	Z.Q. He, Z. Zheng TUB, Beijing, People's Republic of China Z.Q. He, Z. Liu, J. Wei, Y. Zhang FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 Non-axisymmetric RF cavities can produce axially asymmetric acceleration fields. Conventional method using numerical 3-D field tracking to address this feature is time-consuming and thus not appropriate for on-line beam tuning applications. In this paper, we develop analytical treatment of non-axisymmetric RF cavities. Multipole models of cavities are derived using realistic 3-D field in both longitudinal and transverse dimensions. Then, beam dynamics formulism is established. Finally, special case of FRIB quarter-wave resonators are calculated by the model and benchmarked against 3-D field tracking to ensure the efficiency and accuracy of the model.

TUPB103	CSNS DTL Prototyping and RF Tuning	DTL, cavity, linac, vacuum	702
	H.C. Liu, Q. Chen, S. Fu, K.Y. Gong, A.H. Li, J. Peng, Y.C. Xiao, X. Yin IHEP, Beijing, People's Republic of China
	The 324 MHz Alvarez-type Drift Tube Linac (DTL) for the China spallation neutron source will be used to accelerate the H⁻ ion beam of up to 15 mA peak current from 3 to 80 MeV. It consists of four independent tanks, of which the average length is about 8.6 m. Each tank is divided into three short unit tanks about 2.8 m in length for easy manufacture. A full-scale prototype of the first unit tank with 28 drift tubes containing electromagnetic quadrupoles has been constructed to validate the design and to demonstrate the technology. The overall features of the prototype in both key technology and RF tuning are presented. In particular, the influence of the post couplers was studied in the ramped field DTL.

TUPB104	Study of the Beam Dynamics in the RISP Driver Linac	linac, solenoid, lattice, cryomodule	705
	H.J. Kim, J.G. Hwang, D. Jeon IBS, Daejeon, Republic of Korea
	Rare Isotope Science Project (RISP) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. The RISP driver linac which is used to accelerate the beam, for an example, Uranium ions from 0.3 MeV/u to 200 MeV/u consists of superconducting RF cavities and warm quadrupole magnets for focusing heavy ion beams. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the requirements of dynamic errors and correction schemes to minimize the beam centroid oscillation and preserve beam losses under control.

THPB009	Status of CH Cavity and Solenoid Design of the 17 MeV Injector for MYRRHA	solenoid, cavity, focusing, rfq	861
	D. Mäder, H. Klein, H. Podlech, U. Ratzinger, C. Zhang IAP, Frankfurt am Main, Germany
	Funding: This work has been supported by the EU (FP7 MAX contract number 269565) The multifunctional subcritical reactor MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) will be an accelerator driven system (ADS) located in Mol (Belgium). The first accelerating section up to 17 MeV is operated at 176 MHz and consists of a 4-rod-RFQ followed by two room temperature CH cavities with integrated triplet lenses and four superconducting CH structures with intertank solenoids. Each room temperature CH cavity provides about 1 MV effective voltage gain using less than 30 kW of RF power. The superconducting resonators have been optimized for electric peak fields below 30 MV/m and magnetic peak fields below 30 mT. For save operation of the superconducting resonators the magnetic field of the intertank solenoids has to be well shielded towards the CH cavity walls. Different coil geometries have been compared to find the ideal solenoid layout.

THPB031	Status Report on the French High-intensity Proton Injector Project at SACLAY (IPHI)	dipole, rfq, coupling, diagnostics	921
	B. Pottin, M. Desmons, A. France, R. Gobin, O. Piquet CEA/DSM/IRFU, France
	The construction of IPHI (High Power Proton Accelerator) is in its final step of installation. The high intensity light ion source (SILHI) has been built first to produce regularly CW high intensity (over 100 mA) proton beams. The low energy front end of IPHI is based on a 352 MHz, 6 m long Radiofrequency Quadrupole (RFQ) cavity. The RFQ will accelerate beam up to 100 mA with energy up to 3 MeV. A diagnostics line has been designed to measure all the main characteristics of the beam at the RFQ output. In this paper we will present the status for the main components of the injector, in particularly the RFQ fabrication and the RF power facilities.

THPB032	Beam Dynamics Design Aspects for a Proposed 800 MeV H⁻ ISIS Linac	linac, cavity, DTL, rfq	924
	D.C. Plostinar, C.R. Prior, G.H. Rees STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Several schemes have been proposed to upgrade the ISIS Spallation Neutron Source at Rutherford Appleton Laboratory (RAL). One scenario is to develop a new 800 MeV, H⁻ linac and a ~3 GeV synchrotron, opening the possibility of achieving several MW of beam power. In this paper the design of the 800 MeV linac is outlined with an emphasis on the beam dynamics design philosophy. The linac consists of a 3 MeV Front End similar to the one now under construction at RAL (the Front End Test Stand -FETS). Above 3 MeV, a 324 MHz DTL will be used to accelerate the beam up to ~75 MeV. At this stage a novel collimation system will be added to remove the halo and the far off-momentum particles. To achieve the final energy, a 648 MHz superconducting linac will be employed using three families of elliptical cavities with transition energies at ~196 MeV and ~412 MeV.

THPB038	Assembly and RF Tuning of the Linac4 RFQ at CERN	rfq, dipole, linac, cavity	939
	C. Rossi, A. Dallocchio, J. Hansen, J.-B. Lallement, A.M. Lombardi, S.J. Mathot, D. Pugnat, M.A. Timmins, G. Vandoni, M. Vretenar CERN, Geneva, Switzerland M. Desmons, A. France, Y. Le Noa, J. Novo, O. Piquet CEA/DSM/IRFU, France
	The fabrication of Linac4 is progressing at CERN with the goal of making a 160 MeV H⁻ beam available to the LHC injection chain as from 2015. In the Linac4 the first stage of beam acceleration, after its extraction from the ion source, is provided by a Radiofrequency Quadrupole accelerator (RFQ), operating at the RF frequency of 352.2 MHz and which accelerates the ion beam to the energy of 3 MeV. The RFQ, made of three modules, one meter each, is of the four-vane kind, has been designed in the frame of a collaboration between CERN and CEA and has been completely machined and assembled at CERN. The paper describes the assembly of the RFQ structure and reports the results of RF low power measurements, in order to achieve the required accelerating field flatness within 1% of the nominal field profile.

THPB065	Status of the Beam Dynamics Code DYNAC	dipole, rfq, emittance, simulation	990
	E. Tanke, J.A. Rodriguez, W. Wittmer, X. Wu FRIB, East Lansing, Michigan, USA S. Valero CEA, Gif-sur-Yvette, France D. Wang NSCL, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The beam dynamics code DYNAC* was originally developed at CERN. For accelerating elements a set of very accurate quasi-Liouvillian beam dynamics equations was introduced, applicable to protons, heavy ions and non-relativistic electrons. Furthermore, DYNAC contains three space charge routines, including a 3D version*. More recently, a numerical method has been added, capable of simulating a multi charge state ion beam in accelerating elements (i.e. cavities). Beam line devices such as sextupoles and quadrupole-sextupole magnets as well as electrostatic devices are now also included. Capability of second order calculations of such elements for a multi charge state beam has been implemented. Benchmarking of the code, in particular for a multi-charge state beam is discussed. Comparison of beam simulations results with beam measurements on the MSU ReAccelerator (ReA) are reported. The possibility of using DYNAC as an online tool for ReA and FRIB is discussed. DYNAC: A Multi-Particle Beam Dynamics Code for Leptons and Hadrons, E.Tanke et al,LINAC2002 **HERSC: A New 3 Dimensional Space Charge Routine for High Intensity Bunched Beams, E.Tanke et al,LINAC2002

Paper

Title

Other Keywords

Page

SUPB012

Status of CH Cavity and Solenoid Design of the 17 MeV Injector for MYRRHA

solenoid, cavity, focusing, rfq

29

D. Mäder, H. Klein, H. Podlech, U. Ratzinger, C. Zhang
IAP, Frankfurt am Main, Germany

Funding: This work has been supported by the EU (FP7 MAX contract number 269565)
The multifunctional subcritical reactor MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) will be an accelerator driven system (ADS) located in Mol (Belgium). The first accelerating section up to 17 MeV is operated at 176 MHz and consists of a 4-rod-RFQ followed by two room temperature CH cavities with integrated triplet lenses and four superconducting CH structures with intertank solenoids. Each room temperature CH cavity provides about 1 MV effective voltage gain using less than 30 kW of RF power. The superconducting resonators have been optimized for electric peak fields below 30 MV/m and magnetic peak fields below 30 mT. For save operation of the superconducting resonators the magnetic field of the intertank solenoids has to be well shielded towards the CH cavity walls. Different coil geometries have been compared to find the ideal solenoid layout.

MO2A02

Increased Understanding of Beam Losses from the SNS Linac Proton Experiment

proton, linac, focusing, optics

115

J. Galambos, A.V. Aleksandrov, M.A. Plum, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA
E. Laface
ESS, Lund, Sweden
V.A. Lebedev
Fermilab, Batavia, USA

The SNS Linac has been in operation for 6 years, with its power being gradually increased. A major operation goal is the decrease of beam loss. It has been recently suggested that intra- H–beam stripping contributes significantly to beam losses in an H⁻ linac. This was tested experimentally at SNS by accelerating a proton beam. Experimental analysis results are in good agreement with the theoretical estimates. In this paper we present the operational status and experience at the SNS linac, with emphasis on understanding beam loss in terms of intra-H–beam stripping.

Slides MO2A02 [12.869 MB]

MOPLB01

Emittance Control for Different FACET Beam Setups in the SLAC Linac

linac, emittance, klystron, wakefield

138

F.-J. Decker, W.S. Colocho, N. Lipkowitz, Y. Nosochkov, J. Sheppard, H. Smith, Y. Sun, M.-H. Wang, G.R. White, U. Wienands, M. Woodley, G. Yocky
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515.
The linac beam at SLAC requires different setups for different users at FACET (Facility for Advanced aCcelerator Experimental Tests) area, like highly compressed, intense bunches, or lower charge, long bunches. These require typically a lengthy tuning effort since with a energy-time correlation ("chirp") bunch transverse wakefield kicks can be compensated with dispersive trajectory oscillations and vice versa. Lowering the charge or changing the bunch length will destroy this delicate balance. Besides the typical steering to minimize BPMs (Beam Position Monitors) with correctors, we applied different techniques to try to localize beam disturbances like dispersion with phase changes, RF-kicks and RF quadrupole fields turning a klystron off and on, or varying the phase, and finally wakefield kicks with different beam intensities. It is also important to quantify BPM to quadrupole offsets with "bow-tie" plot and that the correctors give the expected kicks with orbit response matrix measurements.

Slides MOPLB01 [0.826 MB]

MOPLB02

Positron Injector Linac Upgrade for SuperKEKB

positron, electron, linac, target

141

T. Kamitani, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, K. Furukawa, Y. Higashi, T. Higo, H. Honma, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

The KEKB B-factory is under an upgrade construction for the SuperKEKB. To achieve 40 times higher luminosity, the linac is required to inject electrons and positrons with higher intensities (e^-: 1 nC → 5 nC, e⁺: 1 nC → 4 nC) and lower emittances (e^-: 300 → 20 μm, e⁺: 2100 → 10 μm). This paper describes the upgrade scheme of the positron source. A new positron capture section will have larger transverse and energy acceptances by introducing a flux concentrator and large aperture L-band and S-band accelerating structures. Beam line layout and quadrupole focusing system will be rearranged for the enlarged beam acceptance. Beam optics is designed to be compatible for positron and electron beams with different energies and emittances. Pulsed quadrupoles and steering magnets are added for better flexibility in optics and orbit tuning. Parameter optimization of the positron source by optics calculation and particle tracking simulation is described.

Slides MOPLB02 [0.575 MB]

MOPB001

Emittance Control for Different FACET Beam Setups in the SLAC Linac

linac, emittance, klystron, wakefield

174

F.-J. Decker, W.S. Colocho, N. Lipkowitz, Y. Nosochkov, J. Sheppard, H. Smith, Y. Sun, M.-H. Wang, G.R. White, U. Wienands, M. Woodley, G. Yocky
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515.
The linac beam at SLAC requires different setups for different users at FACET (Facility for Advanced aCcelerator Experimental Tests) area, like highly compressed, intense bunches, or lower charge, long bunches. These require typically a lengthy tuning effort since with a energy-time correlation ("chirp") bunch transverse wakefield kicks can be compensated with dispersive trajectory oscillations and vice versa. Lowering the charge or changing the bunch length will destroy this delicate balance. Besides the typical steering to minimize BPMs (Beam Position Monitors) with correctors, we applied different techniques to try to localize beam disturbances like dispersion with phase changes, RF-kicks and RF quadrupole fields turning a klystron off and on, or varying the phase, and finally wakefield kicks with different beam intensities. It is also important to quantify BPM to quadrupole offsets with "bow-tie" plot and that the correctors give the expected kicks with orbit response matrix measurements.

MOPB002

Positron Injector Linac Upgrade for SuperKEKB

positron, electron, linac, target

177

T. Kamitani, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, K. Furukawa, Y. Higashi, T. Higo, H. Honma, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

The KEKB B-factory is under an upgrade construction for the SuperKEKB. To achieve 40 times higher luminosity, the linac is required to inject electrons and positrons with higher intensities (e^-: 1 nC → 5 nC, e⁺: 1 nC → 4 nC) and lower emittances (e^-: 300 → 20 μm, e⁺: 2100 → 10 μm). This paper describes the upgrade scheme of the positron source. A new positron capture section will have larger transverse and energy acceptances by introducing a flux concentrator and large aperture L-band and S-band accelerating structures. Beam line layout and quadrupole focusing system will be rearranged for the enlarged beam acceptance. Beam optics is designed to be compatible for positron and electron beams with different energies and emittances. Pulsed quadrupoles and steering magnets are added for better flexibility in optics and orbit tuning. Parameter optimization of the positron source by optics calculation and particle tracking simulation is described.

MOPB014

Electron Model of a Dogbone RLA with Multi-Pass Arcs

linac, electron, dipole, optics

201

S.A. Bogacz, G.A. Krafft, V.S. Morozov, Y. Roblin
JLAB, Newport News, Virginia, USA
K.B. Beard
Muons. Inc., USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by USDOE STTR Grant DE-FG02-08ER86351
The design of a dogbone RLA with linear-field multi-pass arcs was earlier developed for accelerating muons in a Neutrino Factory and a Muon Collider. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over separate-arc or pulsed-arc designs. Such an RLA may have applications going beyond muon acceleration. This paper describes a possible straightforward test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme, in which a 4.35 MeV/c electron beam is injected in the middle of a 2.9 MeV/pass linac with two double-pass return arcs and is accelerated to 17.4 MeV/c in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to a readily available 1.5 GHz. The footprint of a complete RLA fits in a 25x7 m area. The scheme utilizes only fixed field magnets for both injection and extraction. The hardware requirements are not very demanding making it straightforward to implement the scaled design using available equipment.

MOPB067

Results and Performance Simulations of the Main Linac Design for BERLinPro

cavity, HOM, linac, dipole

333

A. Neumann, W. Anders, J. Knobloch
HZB, Berlin, Germany
K. Brackebusch, T. Flisgen, T. Galek, K. Papke, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
B. Riemann, T. Weis
DELTA, Dortmund, Germany

Funding: this work is partly funded by BMBF contract no. 05K10PEA and 05K10HRC
The Berlin Energy Recovery Linac Project (BERLinPro) is designed to develop and demonstrate CW LINAC technology for 100-mA-class ERLs. High-current operation requires an effective damping of higher-order modes (HOMs) of the 1.3 GHz main-linac cavities. We have studied elliptical 7-cell cavities damped by on the whole five waveguides at both ends. Eigenmode computations for geometrical figures of merit show that the present design should allow successful CW linac operation at the maximum beam current of 100 mA/77 pC bunch charge. To verify the results, the external Q factors are compared to the results of S-Parameter simulations that are postprocessed by a pole-fitting technique. First results of scattering parameter measurement on a room-temperature aluminium model are discussed. An outlook presenting the possibilities of combined multi-cavity simulations is included.

MOPB072

Multipole Expansion of the Fields in Superconducting High-Velocity Spoke Cavities

cavity, multipole, linac, simulation

345

R.G. Olave, J.R. Delayen, C.S. Hopper
ODU, Norfolk, Virginia, USA

Multi-spokes superconducting cavities in the high-beta regime are being considered for a number of applications. In order to accurately model the dynamics of the particles in such cavities, knowledge of the fields off-axis are needed. We present a study of the multipoles expansion of the fields from an EM simulation field data for a two-spoke cavity operating at 325 MHz, β = 0.82 and 500 MHz, β = 1.

MOPB095

Design of MEBT for the Project X Injector Experiment at Fermilab

kicker, vacuum, SRF, diagnostics

398

A.V. Shemyakin, C.M. Baffes, A.Z. Chen, Y.I. Eidelman, B.M. Hanna, V.A. Lebedev, S. Nagaitsev, J.-F. Ostiguy, R.J. Pasquinelli, D.W. Peterson, L.R. Prost, G.W. Saewert, V.E. Scarpine, B.G. Shteynas, N. Solyak, D. Sun, M. Wendt, V.P. Yakovlev
Fermilab, Batavia, USA
T. Tang
SLAC, Menlo Park, California, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
The Project X Injector Experiment (PXIE), a test bed for the Project X front end, will be completed at Fermilab at FY12-16. One of the challenging goals of PXIE is demonstration of the capability to form a 1 mA H⁻ beam with an arbitrary selected bunch pattern from the initially 5 mA 162.5 MHz CW train. The bunch selection will be made in the Medium Energy Beam Transport (MEBT) at 2.1 MeV by diverting undesired bunches to an absorber. This paper will present the MEBT scheme and describe development of its elements, including the kickers and absorber.

MOPB098

Planning for Experimental Demonstration of Transverse Emittance Transfer at the GSI UNILAC through Eigen-Emittance Shaping

emittance, coupling, simulation, scattering

404

C. Xiao, O.K. Kester
IAP, Frankfurt am Main, Germany
L. Groening
GSI, Darmstadt, Germany

The minimum transverse emittances achievable in a beam line are determined by the two transverse eigen-emittances of the beam. For vanishing interplane correlations they are equal to the transverse rms-emittances. Eigen-emittances are constants of motion for all symplectic beam line elements, i.e. (even tilted) linear elements. To allow for rms-emittance transfer, the eigen-emittances are changed by a non-symplectic action to the beam, preferably preserving the 4d-rms-emittance. Unlike emittance swapping the presented concept will allow transforming a beam of equal rms-emittances into a beam of different rms-emittances while preserving the 4d-rms-emittance. This contribution will introduce the concept for eigen-emittance shaping and rms-emittance transfer at an ion linac. The actual work status towards the experimental demonstration of the concept at the GSI UNILAC is presented.

TUPB013

Update on the Commissioning Effort at the SwissFEL Injector Test Facility

emittance, laser, electron, optics

504

T. Schietinger
PSI, Villigen, Switzerland

The SwissFEL Injector Test Facility at the Paul Scherrer Institute is the principal test bed and demonstration plant for the SwissFEL project, which aims at realizing a hard-X-ray Free Electron Laser by 2017. Since the spring of 2012 the photoinjector facility has been running with all RF cavities in full operation, allowing beam characterization at energies around 230 MeV with bunch charges between 10 and 200 pC. We give an overview of recent commissioning efforts with particular emphasis on efforts to optimize the emittance of the uncompressed beam.

TUPB058

An Analytical Cavity Model for Fast Linac-Beam Tuning

multipole, cavity, dipole, simulation

609

Z.Q. He, Z. Zheng
TUB, Beijing, People's Republic of China
Z.Q. He, Z. Liu, J. Wei, Y. Zhang
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
Non-axisymmetric RF cavities can produce axially asymmetric acceleration fields. Conventional method using numerical 3-D field tracking to address this feature is time-consuming and thus not appropriate for on-line beam tuning applications. In this paper, we develop analytical treatment of non-axisymmetric RF cavities. Multipole models of cavities are derived using realistic 3-D field in both longitudinal and transverse dimensions. Then, beam dynamics formulism is established. Finally, special case of FRIB quarter-wave resonators are calculated by the model and benchmarked against 3-D field tracking to ensure the efficiency and accuracy of the model.

TUPB103

CSNS DTL Prototyping and RF Tuning

DTL, cavity, linac, vacuum

702

H.C. Liu, Q. Chen, S. Fu, K.Y. Gong, A.H. Li, J. Peng, Y.C. Xiao, X. Yin
IHEP, Beijing, People's Republic of China

The 324 MHz Alvarez-type Drift Tube Linac (DTL) for the China spallation neutron source will be used to accelerate the H⁻ ion beam of up to 15 mA peak current from 3 to 80 MeV. It consists of four independent tanks, of which the average length is about 8.6 m. Each tank is divided into three short unit tanks about 2.8 m in length for easy manufacture. A full-scale prototype of the first unit tank with 28 drift tubes containing electromagnetic quadrupoles has been constructed to validate the design and to demonstrate the technology. The overall features of the prototype in both key technology and RF tuning are presented. In particular, the influence of the post couplers was studied in the ramped field DTL.

TUPB104

Study of the Beam Dynamics in the RISP Driver Linac

linac, solenoid, lattice, cryomodule

705

H.J. Kim, J.G. Hwang, D. Jeon
IBS, Daejeon, Republic of Korea

Rare Isotope Science Project (RISP) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. The RISP driver linac which is used to accelerate the beam, for an example, Uranium ions from 0.3 MeV/u to 200 MeV/u consists of superconducting RF cavities and warm quadrupole magnets for focusing heavy ion beams. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the requirements of dynamic errors and correction schemes to minimize the beam centroid oscillation and preserve beam losses under control.

THPB009

Status of CH Cavity and Solenoid Design of the 17 MeV Injector for MYRRHA

solenoid, cavity, focusing, rfq

861

D. Mäder, H. Klein, H. Podlech, U. Ratzinger, C. Zhang
IAP, Frankfurt am Main, Germany

Funding: This work has been supported by the EU (FP7 MAX contract number 269565)
The multifunctional subcritical reactor MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) will be an accelerator driven system (ADS) located in Mol (Belgium). The first accelerating section up to 17 MeV is operated at 176 MHz and consists of a 4-rod-RFQ followed by two room temperature CH cavities with integrated triplet lenses and four superconducting CH structures with intertank solenoids. Each room temperature CH cavity provides about 1 MV effective voltage gain using less than 30 kW of RF power. The superconducting resonators have been optimized for electric peak fields below 30 MV/m and magnetic peak fields below 30 mT. For save operation of the superconducting resonators the magnetic field of the intertank solenoids has to be well shielded towards the CH cavity walls. Different coil geometries have been compared to find the ideal solenoid layout.

THPB031

Status Report on the French High-intensity Proton Injector Project at SACLAY (IPHI)

dipole, rfq, coupling, diagnostics

921

B. Pottin, M. Desmons, A. France, R. Gobin, O. Piquet
CEA/DSM/IRFU, France

The construction of IPHI (High Power Proton Accelerator) is in its final step of installation. The high intensity light ion source (SILHI) has been built first to produce regularly CW high intensity (over 100 mA) proton beams. The low energy front end of IPHI is based on a 352 MHz, 6 m long Radiofrequency Quadrupole (RFQ) cavity. The RFQ will accelerate beam up to 100 mA with energy up to 3 MeV. A diagnostics line has been designed to measure all the main characteristics of the beam at the RFQ output. In this paper we will present the status for the main components of the injector, in particularly the RFQ fabrication and the RF power facilities.

THPB032

Beam Dynamics Design Aspects for a Proposed 800 MeV H⁻ ISIS Linac

linac, cavity, DTL, rfq

924

D.C. Plostinar, C.R. Prior, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Several schemes have been proposed to upgrade the ISIS Spallation Neutron Source at Rutherford Appleton Laboratory (RAL). One scenario is to develop a new 800 MeV, H⁻ linac and a ~3 GeV synchrotron, opening the possibility of achieving several MW of beam power. In this paper the design of the 800 MeV linac is outlined with an emphasis on the beam dynamics design philosophy. The linac consists of a 3 MeV Front End similar to the one now under construction at RAL (the Front End Test Stand -FETS). Above 3 MeV, a 324 MHz DTL will be used to accelerate the beam up to ~75 MeV. At this stage a novel collimation system will be added to remove the halo and the far off-momentum particles. To achieve the final energy, a 648 MHz superconducting linac will be employed using three families of elliptical cavities with transition energies at ~196 MeV and ~412 MeV.

THPB038

Assembly and RF Tuning of the Linac4 RFQ at CERN

rfq, dipole, linac, cavity

939

C. Rossi, A. Dallocchio, J. Hansen, J.-B. Lallement, A.M. Lombardi, S.J. Mathot, D. Pugnat, M.A. Timmins, G. Vandoni, M. Vretenar
CERN, Geneva, Switzerland
M. Desmons, A. France, Y. Le Noa, J. Novo, O. Piquet
CEA/DSM/IRFU, France

The fabrication of Linac4 is progressing at CERN with the goal of making a 160 MeV H⁻ beam available to the LHC injection chain as from 2015. In the Linac4 the first stage of beam acceleration, after its extraction from the ion source, is provided by a Radiofrequency Quadrupole accelerator (RFQ), operating at the RF frequency of 352.2 MHz and which accelerates the ion beam to the energy of 3 MeV. The RFQ, made of three modules, one meter each, is of the four-vane kind, has been designed in the frame of a collaboration between CERN and CEA and has been completely machined and assembled at CERN. The paper describes the assembly of the RFQ structure and reports the results of RF low power measurements, in order to achieve the required accelerating field flatness within 1% of the nominal field profile.

THPB065

Status of the Beam Dynamics Code DYNAC

dipole, rfq, emittance, simulation

990

E. Tanke, J.A. Rodriguez, W. Wittmer, X. Wu
FRIB, East Lansing, Michigan, USA
S. Valero
CEA, Gif-sur-Yvette, France
D. Wang
NSCL, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The beam dynamics code DYNAC* was originally developed at CERN. For accelerating elements a set of very accurate quasi-Liouvillian beam dynamics equations was introduced, applicable to protons, heavy ions and non-relativistic electrons. Furthermore, DYNAC contains three space charge routines, including a 3D version**. More recently, a numerical method has been added, capable of simulating a multi charge state ion beam in accelerating elements (i.e. cavities). Beam line devices such as sextupoles and quadrupole-sextupole magnets as well as electrostatic devices are now also included. Capability of second order calculations of such elements for a multi charge state beam has been implemented. Benchmarking of the code, in particular for a multi-charge state beam is discussed. Comparison of beam simulations results with beam measurements on the MSU ReAccelerator (ReA) are reported. The possibility of using DYNAC as an online tool for ReA and FRIB is discussed.
*DYNAC: A Multi-Particle Beam Dynamics Code for Leptons and Hadrons, E.Tanke et al,LINAC2002
**HERSC: A New 3 Dimensional Space Charge Routine for High Intensity Bunched Beams, E.Tanke et al,LINAC2002