IPAC2012 - List of Keywords (quadrupole)

Paper	Title	Other Keywords	Page
MOEPPB004	A Compact Ring Design with Tunable Momentum Compaction	damping, dynamic-aperture, dipole, emittance	82
	Y. Sun SLAC, Menlo Park, California, USA
	A storage ring with tunable momentum compaction has the advantage in achieving diﬀerent RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and pre- damping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and ﬁne tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

MOEPPB008	Simulation of Hollow Electron Beam Collimation in the Fermilab Tevatron Collider	electron, simulation, collimation, collider	94
	G. Stancari, I.A. Morozov, A. Valishev Fermilab, Batavia, USA D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. This work was partially supported by the US LHC Accelerator Research Program (LARP). The concept of augmenting the conventional collimation system of high-energy storage rings with a hollow electron beam was successfully demonstrated in experiments at the Tevatron. A reliable numerical model is required for understanding particle dynamics in the presence of a hollow beam collimator. Several models were developed to describe imperfections of the electron beam profile and alignment. The features of the imperfections are estimated from electron beam profile measurements. Numerical simulations of halo removal rates are compared with experimental data taken at the Tevatron.

MOPPC002	Local Chromatic Correction Scheme and Crab-waist Collisions for an Ultra-low β^* at the LHC	sextupole, optics, luminosity, resonance	118
	J.L. Abelleira, S. Russenschuck, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland J.L. Abelleira EPFL, Lausanne, Switzerland C. Milardi, M. Zobov INFN/LNF, Frascati (Roma), Italy K. Ohmi KEK, Ibaraki, Japan D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu- CARD, grant agreement no. 227579. We discuss potential merits and the parameter range of interest for a possible crab-waist collision scheme at the LHC, and report preliminary optics studies of a local chromatic correction scheme with flat beams (β_x^>>β_y^), which could boost the LHC luminosity by about an order of magnitude and would also allow for crab-waist collisions.

MOPPC004	Experiments on the Margin of Beam Induced Quenches for LHC Superconducting Quadrupole Magnet in the LHC	injection, proton, kicker, monitoring	124
	C. Bracco, W. Bartmann, M. Bednarek, B. Goddard, E.B. Holzer, A. Nordt, M. Sapinski, R. Schmidt, M. Solfaroli Camillocci, M. Zerlauth, E.N. del Busto CERN, Geneva, Switzerland
	Protection of LHC equipment relies on a complex system of collimators to capture injected or circulating beam in case of LHC injection kicker magnet failures. However, for specific failures of the injection kicker, the beam can graze the injection protection collimators and induce quenches of downstream superconducting magnets. This occurred twice during 2011 operation and can also not be excluded during further operation. Tests were performed during Machine Development periods of the LHC to assess the quench margin of the quadrupole located just downstream of the last injection protection collimator in point 8. In addition to the existing Quench Protection System, a special monitoring instrumentation was installed at this magnet to detect any resistance increase below the quench limit. The correlation between the magnet and Beam Loss Monitor signals was analysed for different beam intensities and magnet current. The results of the experiments are presented in this paper.

MOPPC006	90m Optics Studies and Operation in the LHC	optics, proton, injection, target	130
	H. Burkhardt, G.J. Müller, S. Redaelli, R. Tomás, G. Vanbavinckhove, J. Wenninger CERN, Geneva, Switzerland S. Cavalier LAL, Orsay, France
	A high β^* = 90 m optics was commissioned and used for first very forward physics operation in the LHC in 2011. The experience gained from working with this optics in 5 studies and operation periods in 2011 was very positive. The target β^* = 90 m was reached by a de-squeeze from the standard 11 m injection and ramp optics on the first attempt and collisions and first physics results obtained in the second study. The optics was measured and corrected with good precision. The running conditions were very clean and allowed for measurements with roman pots very close to the beam.

MOPPC007	Plans for High Beta Optics in the LHC	optics, emittance, insertion, scattering	133
	H. Burkhardt, A. Macpherson CERN, Geneva, Switzerland S. Cavalier, P.M. Puzo LAL, Orsay, France
	Based on what has been learned with the first high β^* = 90 m operation in 2011, we describe the potential and practical scenarios for reaching very high β^* in the LHC in 2012 and beyond. Very high β^* optics require dedicated running time and conditions in the LHC. We describe a plan which is optimized to maximize the physics potential in a minimum of dedicated running time.

MOPPC010	Parametric Study of Optics Options for the HL-LHC Project	optics, luminosity, insertion, sextupole	142
	R. De Maria CERN, Geneva, Switzerland
	Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, cofunded by the DoE, USA and KEK, Japan. The LHC Upgrade studies have been recently formalized into the High-Luminosity LHC (HL-LHC) project. The paper explores the parameter space in terms minimum beta star (flat and round), and luminosity leveling scenarios, constrained by the triplet gradient and aperture and still compatible with optics solutions based on the ATS scheme. The limitations of the proposed solutions, essentially given by the preservation of the dynamic aperture in the presence of large beta-beating waves induced in the arcs by the squeezing scheme are investigated. The results will be combined in scaling laws benchmarked with existing fully developed scenarios. S. Fartoukh et al., "The Achromatic Telescopic Squeezing (ATS) scheme: from initial motivations to basic principles, and first demonstration at the LHC," these proceedings.

MOPPC011	Optics and Layout Solutions for the HL-LHC with Large Aperture Nb3Sn and Nb-Ti Inner Triplets	optics, dynamic-aperture, insertion, injection	145
	S.D. Fartoukh, R. De Maria CERN, Geneva, Switzerland
	Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, co-funded by the DoE, USA and KEK, Japan. The LHC Upgrade studies, formalized into the High-Luminosity LHC (HL-LHC) project, relies on the feasibility of very low β^, and in particular on a novel achromatic squeezing mechanism, the ATS scheme which is presently under test in the LHC. We present two optics and layout scenario for the HL-LHC using the ATS scheme, one based on Nb3Sn triplet quadrupoles with a coil aperture compatible with an operational gradient of 150T/m and a backup scenario based on NbTi compatible with an operational gradient of 100T/m. The solution obtained are analyzed in terms of β^* reach (flat or round), mechanical acceptance, optics flexibility, chromatic properties, and impact on the dynamic aperture due to the large beta-beating waves induced in the arcs by the ATS scheme. * S. Fartoukh et al., "The Achromatic Telescopic Squeezing (ATS) scheme: from initial motivations to basic principles, and first demonstration at the LHC," these proceedings.

MOPPC016	Combined Ramp and Squeeze at the Large Hadron Collider	optics, injection, collider, dipole	157
	S. Redaelli, M. Lamont, G.J. Müller, R. Tomás, J. Wenninger CERN, Geneva, Switzerland N. Ryckx EPFL, Lausanne, Switzerland
	In the first two years of operation of the CERN Large Hadron Collider (LHC), the betatron squeeze has been carried out at constant flat top energy of 3.5 TeV. Squeeze setting functions are separated from the energy ramp functions. This ensured a maximum flexibility during commissioning because stopping at all intermediate optics for detailed measurements was possible. In order to then improve the efficiency of the operational cycle, combining the ramp and squeeze has been considered. In this paper, the various possibilities for this scheme are reviewed, and proposals of optimized operational cycles with combined ramp and squeeze are presented for different energies. Results of beam tests are also discussed.

MOPPC020	Field Tolerances for the Triplet Quadrupoles of the LHC High Luminosity Lattice	multipole, dynamic-aperture, target, lattice	169
	Y. Jiao, Y. Cai, Y. Nosochkov, M.-H. Wang SLAC, Menlo Park, California, USA R. De Maria, S.D. Fartoukh, M. Giovannozzi, E. McIntosh CERN, Geneva, Switzerland
	Funding: This work is supported by the U.S. Department of Energy under contract # DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP). It has been proposed to implement an Achromatic Telescopic Squeezing (ATS) scheme* in the high luminosity LHC lattice to reduce the beta functions at the Interaction Points (IP) up to a factor of 8. As a consequence, the nominal 4.5-km peak beta functions reached in the inner triplets at collision will be increased by the same factor. This therefore justifies the installation of new, larger aperture superconducting triplet quadrupoles. These higher beta functions will enhance the effects of the triplet quadrupole field errors leading to smaller beam dynamic aperture. To maintain the acceptable dynamic aperture, the effects of the triplet multipole field errors must be re-evaluated, thus specifying new tolerances. Such a study has been performed for the so-called “4444” collision optics of the ATS scheme, where the IP beta functions are reduced by a factor of 4 in both planes with respect to a pre-squeezed value of 60 cm at two collision points. The dynamic aperture calculations were performed using SixTrack. The impact on the triplets’ field quality is studied and presented in details. * S. Fartoukh, “An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade”, Proc. of IPAC11, p. 2088 (2011).

MOPPC029	Off-momentum Beat-beat Correction in the RHIC Proton Run	sextupole, simulation, proton, lattice	196
	Y. Luo, M. Bai, W. Fischer, A. Marusic, K. Mernick, S.M. White 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. In this article we will present the measurement and correction of the off-momentum β^*-beat in the RHIC proton run. The beta-beat will be measured with the AC dipole and by shifting RF frequency. We will focus on the correction of the off-momentum beta-beat at the interaction points IP6 and IP8 with the arc chromatic sextupole families. The effects of the off-momentum beta-beat correction on the global chromaticities and dynamic aperture will be estimated through beam experiments and the numerical simulation.

MOPPC045	Scaled Electron Model of a Dogbone Muon RLA with Multi-pass Arcs	linac, electron, dipole, optics	235
	S.A. Bogacz, A. Hutton, G.A. Krafft, V.S. Morozov, Y. Roblin JLAB, Newport News, Virginia, USA K.B. Beard, R.P. Johnson Muons, Inc, Batavia, 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 for a future Neutrino Factory and 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 single pass 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 an area of 25 by 7 m. The scheme utilizes only fixed magnetic fields including injection and extraction. The hardware requirements are not very demanding, making it feasible to utilize the existing technologies. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

MOPPC057	Some Comments to Magnetic Field Representation for Beam Dynamic Calculations	multipole, dipole, vacuum, resonance	262
	P. Schnizer, E.S. Fischer GSI, Darmstadt, Germany A. Mierau TEMF, TU Darmstadt, Darmstadt, Germany B. Schnizer TUG/ITP, Graz, Austria
	Machines with high currents and small apertures, as used for SIS100 of the FAIR project, require a sincere understanding of the resonances excited by the magnetic field distortions; typically performed by tracking codes. These codes model the field errors using a Taylor Series approximation of the field quality at the track of the ideal particle. The path of the particle within the elliptic aperture of the dipole is curved; thus the standard approach of using plane circular multipoles fails to model the real symmetry of the magnetic field, an important feature of effective field description for beam loss calculations. Therefore toroidal elliptic multipoles were developed which allow describing the magnetic field concisely in an elliptic vacuum chamber in curved dipoles and quadrupoles. In this talk we present the appropriate description and its limitation, illustrate their usefullness based on the static and transient magnetic field measurements of the first curved SIS100 dipole next to the SIS18 dipole.

MOPPC074	Evolution of MAD-X in the Framework of LHC Upgrade Studies	multipole, simulation, optics, luminosity	304
	A. Latina, L. Deniau CERN, Geneva, Switzerland
	The design efforts for the High Luminosity upgrade of the Large Hadron Collider (HL-LHC) will require significant extensions of the MAD-X code widely used for designing and simulating particles accelerators. For this purpose, several new capabilities have been added to the code, namely the possibility to simulate crab cavities for crossing angle compensation, with their imperfections; the selective introduction of thick quadrupole elements for particles tracking, improving the previous implementation entirely based on thin-lenses; and the upgrade of the interface to SixTrack used for distributed tracking with, e.g., LHC@home. These changes are framed into a global redesign of the MAD-X architecture meant to consolidate its structure, improve its performances, and increase its flexibility. Such improvements are described in details in the present paper.

MOPPC079	Modelling of the EMMA ns-FFAG Ring Using GPT	space-charge, emittance, injection, electron	319
	R.T.P. D'Arcy, S. Jolly UCL, London, United Kingdom J.K. Jones, B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	EMMA (Electron Machine with Many Applications) is a prototype non-scaling Fixed-Field Alternating Gradient (ns-FFAG) accelerator whose construction at Daresbury Laboratory, UK, was completed in the autumn of 2010. The energy recovery linac ALICE will serve as an injector for EMMA, within an energy range of 10 to 20 MeV. The injection line consists of a symmetric 30 degree dogleg to extract the beam from ALICE, a matching section and a tomography section for transverse emittance measurements. This is followed by a transport section to the injection point of the EMMA ring. The ring is composed of 42 cells, each containing one focusing and one defocusing quadrupole. Acceleration over many turns of the EMMA machine has recently been confirmed. In some cases the bunch will traverse upwards of 100 turns, at which point the effects of space-charge may be significant. It is therefore necessary to model the electron beam transport in the ring using a code capable of both calculating the effect of and compensating for space-charge. Therefore the General Particle Tracer (GPT) code has been used. A range of injection beam parameters have been modeled for comparison with experimental results.

MOPPC082	Beam Dynamics Simulations inProject X RFQ with CST Studio Suite	rfq, simulation, acceleration, linac	328
	G.V. Romanov Fermilab, Batavia, USA
	Typically the RFQs are designed using the Parmteq, DesRFQ and other similar specialized codes, which produces the files containing the field and geometrical parameters for every cell. The beam dynamic simulations with these analytical fields are, of course, ideal realizations of the designed RFQs. The new advanced computing capabilities made it possible to simulate beam and even dark current in the realistic 3D electromagnetic fields in the RFQs that may reflect cavity tuning, presence of tuners and couplers, RFQ segmentation etc. The paper describes the utilization of full 3D field distribution obtained with CST Studio Suite for beam dynamic simulations using both PIC solver of CST Particle Studio and the beam dynamic code TRACK.

MOPPC083	LinguaFranca - A Graphical User Interface for Accelerator Modeling	simulation, lattice, optics, collider	331
	T.J. Roberts Muons, Inc, Batavia, USA
	This is a proposed project to develop an innovative Graphical User Interface that permits users to construct, explore, optimize, and evaluate accelerator systems efficiently and effectively. While it will be designed with students in mind, accelerator physicists will also find it useful in dealing with the plethora of modeling tools and their different languages. The internal representation of the system is specifically designed to be useable as a text-based description of the system, and to make it easy for users to interface it to essentially any accelerator-modeling tool, regardless of its description language. Many accelerator designers have expressed frustration with the current “Tower of Babel” among modeling programs, and this project will address that directly. In particular, this will make it straightforward to use fast but less realistic programs to design and optimize a system, and then use slower but more realistic programs to evaluate its performance. Graphical interfaces are emphasized, making it easy to construct the system graphically, display the system and its beam, and use on-screen controls to vary parameters and observe their effects immediately.

MOPPD041	Beam Loss Protection for a 2.3 Megawatt LBNE Proton Beam	dipole, proton, power-supply, target	454
	R.M. Zwaska, S.C. Childress, A.I. Drozhdin, N.V. Mokhov, I.S. Tropin Fermilab, Batavia, USA
	Funding: U.S. Department of Energy. Severe limits are required for allowable beam loss during extraction and transport of a 2.3 MW primary proton beam for the Long Baseline Neutrino Experiment (LBNE) at Fermilab. Detailed simulations with the STRUCT and MARS codes have evaluated the impact of beam loss of 1.6·10¹⁴ protons per pulse at 120 GeV, ranging from a single pulse full loss to sustained small fractional loss. It is shown that localized loss of a single beam pulse at 2.3 MW will result in a destructive event: beam pipe failure, damaged magnets and high levels of residual radiation inside the tunnel. A sustained full beam loss would be catastrophic. Acceptable beam loss limits have been determined and robust solutions developed to enable efficient proton beam operation under these constraints.

MOPPD049	The Layout of the High Energy Beam Transport for the European Spallation Source	target, octupole, linac, beam-transport	475
	A.I.S. Holm, S.P. Møller, H.D. Thomsen ISA, Aarhus, Denmark
	The status of the High Energy Beam Transport (HEBT) line for the European Spallation Source (ESS) is presented. The HEBT brings the beam from the underground linac to the target at surface level. The main design objectives of the HEBT, such as space for upgrades, producing the desired target footprint etc. are discussed and the preferred design is shown. Large amplitude particles, a halo, are formed in the last part of the linac. Hence, every given value of the peak current density at the target is correlated with a certain power deposited outside the beam footprint. This correlation is studied and optimized. Furthermore, first studies of the vertical stability of the beam footprint and profile on target due to misalignment or mismatch of the incoming beam are made.

MOPPD051	Performance of Resonant Slow Extraction from J-PARC Main Ring	extraction, feedback, proton, septum	481
	M. Tomizawa, Y. Arakaki, T. Kimura, S. Murasugi, R. Muto, H. Nakagawa, K. Okamura, H. Sato, Y. Shirakabe, T. Toyama, E. Yanaoka, M. Yoshii KEK, Ibaraki, Japan D. Horikawa Sokendai, Ibaraki, Japan K. Mochiki Tokyo City University, Tokyo, Japan A. Schnase JAEA/J-PARC, Tokai-mura, Japan
	Proton beam accelerated by the J-PARC main ring (MR) with an imaginary transition lattice is slowly extracted by a third integer resonant extraction scheme and delivered to the hadron experimental hall. One of the critical issues in the slow extraction from a high intensity proton synchrotron is the inevitable beam loss caused by the extraction process at septum devices. A design with low beam loss (high extraction efficiency) is required to reduce machine damage and radiation exposure during hands-on maintenance. We have designed the slow extraction scheme to obtain high extraction efficiency for the MR lattice. The scheme has a large step size and a small angular spread enabling a hit rate of the beam on the developed thin septum device. Since the first 30 GeV proton beam was successfully delivered to the experimental hall in January 2009, an extremely high extraction efficiency of 99.5% has been achieved by an intensive beam tuning. In this paper, we report details of such performance. We will also describe some schemes to improve the serious spiky spill time structure due to large current ripples from the power supplies for the bending and quadrupole magnets.

MOPPD057	CERN PSB-to-PS Transfer Modifications for the 2 GeV Upgrade	injection, optics, dipole, septum	493
	W. Bartmann, J. Borburgh, S.S. Gilardoni, B. Goddard, A. Newborough, S. Pittet, R. Steerenberg CERN, Geneva, Switzerland C.H. Yu IHEP, Beijing, People's Republic of China
	Within the frame of the CERN PS Booster (PSB) energy upgrade from 1.4 to 2 GeV, the PSB to PS transfer line will be adapted for pulse-to-pulse modulated operation. A modified lattice is presented including a re-design of the switching dipole between ISOLDE and PS and additional collimators to protect the PS injection septum. Optics solutions optimized for small emittance LHC beams as well as for the large emittance high-intensity beams are shown.

MOPPD060	Modified Extraction Scheme for the CERN PS Multi-Turn Extraction	extraction, septum, kicker, beam-losses	502
	M. Giovannozzi, S.S. Gilardoni, C. Hernalsteens, A. Lachaize, G. Métral CERN, Geneva, Switzerland
	High-activation of the extraction magnetic septum of the CERN PS machine was observed due to the losses of the continuous beam extracted via the Multi-Turn Extraction (MTE) method. A possible mitigation measure consists of using an existing electrostatic septum, located upstream of the extraction magnetic septum, to deflect the beam. This would highly decrease the beam losses, and hence the induced activation, during the rise time of the MTE kickers due to the reduced thickness of the electrostatic septum with respect to the magnetic one. The layout of this new extraction will be described in detail and the results of beam measurements presented.

MOPPP015	Status of the BERLinPro Energy Recovery Linac Project	cavity, linac, SRF, booster	601
	J. Knobloch, M. Abo-Bakr, W. Anders, R. Barday, K.B. Bürkmann-Gehrlein, V. Dürr, S.C. Heßler, A. Jankowiak, T. Kamps, O. Kugeler, B.C. Kuske, P. Kuske, A.N. Matveenko, G. Meyer, R. Müller, A. Neumann, K. Ott, Y. Petenev, D. Pflückhahn, T. Quast, J. Rahn, S.G. Schubert HZB, Berlin, Germany
	Funding: Funding provided by the BMBF and the State of Berlin In October 2010 Helmholtz Zentrum Berlin received funding to design and build the Berlin Energy Recovery Linac Project BERLinPro. The goal of this compact ERL is to develop the accelerator physics and technology required to generate and accelerate a 100-mA, 1 mm·mrad emittance beam. Given the flexibility of ERLs, other operation modes such as short-bunch operation will also be investigated. The BERLinPro technology and know-how can then be transferred to a variety of ERL-based applications. Presently, BERLinPro is in the design phase and the optics has been settled. Furthermore, first beam has been achieved with a superconducting RF photoinjector, which represents an important step towards realizing a CW injector for BERLinPro. An overview of the present status and the conceptual design report is presented.

MOPPP038	Optics Design and Layout for the Electron Beam Test Facility at Daresbury Laboratory	gun, beam-transport, laser, emittance	646
	D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J.K. Jones Cockcroft Institute, Warrington, Cheshire, United Kingdom
	An Electron Beam Test Facility (EBTF) is being developed at Daresbury Laboratory to provide the beam for industrial applications and as a front end of future light source facility test under consideration. The RF photoinjector will deliver ~6 MeV beam to industrial users* and will serve as an injector for the future light source facility under consideration at Daresbury*. The Photoinjector design in first phase consists of 2.5 cell RF gun (on loan from Strathclyde) to be driven by Ti:S laser. The photo injector design is aimed to deliver bunches with 10-250 pC bunch charge at low transverse emittances and short bunch lengths. The beam transport optics design described in this paper includes a dedicated diagnostics section capable of measuring ultra short and ultra low emittance bunches and transport to two user areas. P. McIntosh, these proceedings. ** J. Clarke, these proceedings.

MOPPR010	Simultaneous Measurement of Emittance at the Storage Ring and the External Beamlines of ELSA	emittance, synchrotron, extraction, diagnostics	792
	S. Zander, F. Frommberger, W. Hillert, D. Proft ELSA, Bonn, Germany
	Funding: Funded by the DFG within the SFB / TR 16. The Electron Stretcher Facility (ELSA) consists of several accelerator stages, the last one being a storage ring providing a beam of polarized electrons of up to 3.5 GeV. To ensure a high duty cycle, a slow extraction via a third integer resonance is applied at ELSA. The resonance extraction cause a variation of the emittance in the external beamline. A system for simultaneous measurement of emittance in the storage ring and the external beamlines has been installed. First results including a comparison of both emittances will be shown.

MOPPR023	Stripline BPM with Integral In-Vacuo Termination	impedance, pick-up, vacuum, coupling	828
	A. Stella, A. Ghigo, V.L. Lollo, F. Marcellini, M. Serio INFN/LNF, Frascati (Roma), Italy
	We report the design and realization of a stripline type beam position monitor to be used in the SPARC LAB transfer lines. While the directional properties provided by matched termination at the downstream end are not strictly required in a transfer line, yet matched loads at the end of the stripline electrodes are preferable to reduce the loss factor and to avoid unwanted reflection to the detection electronic. The Integration of a matched resistive load inside the vacuum chamber allows to halve the number of UHV feedthroughs.

MOPPR024	Non-intercepting Emittance Measurements by means of Optical Diffraction Radiation Interference for High Brightness Electron Beam	radiation, electron, emittance, target	831
	A. Cianchi Università di Roma II Tor Vergata, Roma, Italy V. Balandin, N. Golubeva, K. Honkavaara, G. Kube DESY, Hamburg, Germany M. Castellano, E. Chiadroni INFN/LNF, Frascati (Roma), Italy L. Catani INFN-Roma II, Roma, Italy
	Conventional intercepting transverse electron beam diagnostics, e.g. based on Optical Transition Radiation (OTR), cannot tolerate high power beams without remarkable mechanical damages of the diagnostics device. Optical Diffraction Radiation (ODR) is an excellent candidate for the measurements of the transverse phase space parameters in a non-intercepting way. One of the main limitations of this method is the low signal to noise ratio, mainly due to the unavoidable synchrotron radiation background. This problem can be overcome by using ODRI (Optical Diffraction Radiation Interference). In this case the beam goes through two slits opened on metallic foils, placed in a distance shorter than the radiation formation zone. Thanks to the shielding effect of the first screen a nearly background-free ODR interference pattern can be measured allowing the determination of the beam size and the angular divergence. Here we report the first measurements, carried out at FLASH (DESY, Germany), of the beam emittance using ODRI. Our results demonstrate the unique potential of this technique.

MOPPR039	Development of Beam Position Monitor for PEFP Linac and Beam line	linac, proton, coupling, DTL	864
	J.Y. Ryu, Y.-S. Cho, J.-H. Jang, H.S. Kim, H.-J. Kwon, K.T. Seol KAERI, Daejon, Republic of Korea
	Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government. The development of the Beam Position Monitor (BPM) is in progress for the linac and beam lines of the Proton Engineering Frontier Project (PEFP). We choose a strip line BPM for the PEFP 20-MeV and 100-MeV beam lines in order to increase the sensitivity of the relatively long bunches in the beam lines. We also selected the same type BPM for the proton linac in the energy range between 20-MeV and 100-MeV. The prototype BPM was designed, fabricated and tested at KAERI site, where the 20-MeV linac was operated. To check the performance of the BPM, we performed the field mapping. The characteristics and test results of the BPM on the test bench as well as with 20-MeV proton beam will be presented in this paper.

MOPPR042	Characterization Tests of a Stripline Beam Position Monitor for the CLIC Drive Beam	impedance, extraction, simulation, feedback	873
	A. Benot-Morell, A. Faus-Golfe, J.J. García-Garrigós IFIC, Valencia, Spain A. Benot-Morell, L. Søby CERN, Geneva, Switzerland J.M. Nappa, J. Tassan-Viol, S. Vilalte IN2P3-LAPP, Annecy-le-Vieux, France S.R. Smith SLAC, Menlo Park, California, USA
	Funding: FPA2010-21456-C02-01, SEIC-2010-00028 A prototype of a stripline Beam Position Monitor (BPM) with its associated readout electronics has been developed at CERN in collaboration with SLAC, LAPP and IFIC. In this paper, the design and simulations of the BPM with the analog readout chain and the BPM test bench are described, and the results of the first characterization tests are presented. The position resolution and accuracy parameters are expected to be below 2μm and 20μm respectively for a beam with a bunching frequency of 12GHz, an average current of 101A and a machine repetition rate of 50Hz.

MOPPR044	Optics and Emittance Studies using the ATF2 Multi-OTR System	coupling, emittance, target, controls	879
	J. Alabau-Gonzalvo, C. Blanch Gutierrez, A. Faus-Golfe, J.J. García-Garrigós, J. Resta-López IFIC, Valencia, Spain J. Cruz, D.J. McCormick, G.R. White, M. Woodley SLAC, Menlo Park, California, USA
	Funding: Funding Agency: FPA2010-21456-C02-01. Work supported in part by Department of Energy Contract DE-AC02-76SF00515. A multi-OTR system (4 beam ellipse diagnostic devices based on optical transition radiation) was installed in the extraction line of ATF2 and has been fully operational since September 2011. The OTRs have been upgraded with a motorized zoom-control lens system to improve beam finding and accommodate different beam sizes. The system is being used routinely for beam size and emittance measurements as well as coupling correction. In this paper we present measurements performed during the winter run of 2011 and the early 2012 runs. We show the reconstruction of twiss parameters and emittance, discuss the reliability of the OTR system and show comparisons with simulations. We also present new work to calculate all 4 coupling terms and form the “4-D” intrinsic emittance of the beam utilizing all the information available from the 2-D beam profile images. We also show details and experimental results for performing a 1-shot automated coupling correction.

MOPPR059	Modeling Space-charge and its Influence on the Measurement of Phase Space in ALICE by Tomographic Methods	space-charge, injection, electron, diagnostics	918
	M.G. Ibison, D.J. Holder The University of Liverpool, Liverpool, United Kingdom K.M. Hock, B.D. Muratori, A. Wolski Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: STFC. ALICE is an experimental electron accelerator designed to operate over a range of energies up to 35 MeV, and with up to 80 pC bunch charge. A dedicated tomography diagnostic section allows measurement of the transverse phase space with different beam parameters. In the low-energy, high-charge regime, space charge effects must be considered: to quantify these effects, the tracking code GPT has been used to simulate beams in the tomography diagnostic section. The results can be compared with simplified models, and with experimental measurements.

MOPPR060	Calibration of the EMMA Beam Position Monitors: Position, Charge and Accuracy	pick-up, injection, simulation, diagnostics	921
	I.W. Kirkman The University of Liverpool, Liverpool, United Kingdom J.S. Berg BNL, Upton, Long Island, New York, USA G. Cox STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom D.J. Kelliher, S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	The accurate determination of transverse beam position is essential to understanding the performance of an accelerator system, and this is particularly the case with non-scaling FFAG machines such as EMMA, where, due to fundamental principles of design, the beam may deviate widely from the central beampipe axis. This paper describes the various modelling approaches taken for the three different button pickup assemblies used in EMMA, and the subsequent methods of calibration (‘mappings’) which allow beam position and charge to be deduced from the processed BPM signals. The use and validity of the modelling and mapping approach adopted is described, and the contributions to positional and bunch charge uncertainty arising from these procedures is discussed.

MOPPR061	Computing Bunch Charge, Position, and BPM Resolution in Turn-by-Turn EMMA BPMs	pick-up, EPICS, injection, controls	924
	A. Kalinin, J.K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom R.G. Borrell WareWorks Ltd, Manchester, United Kingdom G. Cox STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom D.J. Kelliher, S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom I.W. Kirkman Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The NS-FFAG electron model ‘EMMA’ and its Injection and Extraction Lines are equipped with a total of 53 EPICS VME BPMs. In the BPMs, each opposite button signal pair is time-domain-multiplexed into one channel as a pulse doublet. The recording of turn-by-turn data into the BPM memory is triggered by the bunch itself on each of its passages. For each accelerating cycle, the BPMs deliver a snapshot of a turn-by-turn trajectory measured in each of 42 cells. Additional BPMs (two pairs) are used to obtain a Poincare map. We describe the EPICS architecture, and a set of Python data processing algorithms that are used to automatically set a BPM intensity range, to eliminate an error due to tails of the doublet pulses, to calculate the bunch charge and position, and, for a set of injections, to find the BPM resolution. We use three types of button pickup mappings* that allow: to eliminate bunch charge signal dependence on offset, to get a linear offset response, and to eliminate ‘quadrupole’ signal dependence on offset as well (which is used in resolution calculation). We present beam measurement results collected in 2011 runs. * A. Kalinin et al., Proc. of IPAC’10, MOPE068, p. 1134, (2010. ** I. Kirkman, these proceedings.

MOPPR063	Exploiting the Undesired: Beam-gas Interactions in the LHC	vacuum, radiation, simulation, proton	927
	R. Versaci, V. Baglin, M. Brugger CERN, Geneva, Switzerland A. Mereghetti UMAN, Manchester, United Kingdom
	The vacuum inside the LHC pipes has a key role in correct operation of the accelerator. The interaction of the beam with residual gas in the pipes can lead to the loss of the beam itself and damage accelerator components. Nevertheless, beam-gas interactions can be exploited to indirectly measure the gas pressure inside the beam pipe, detecting the secondaries produced. The showers generated are detected by Beam Loss Monitors, whose signals depend on the gas pressure. This technique would also allow to punctually measure the gas pressure in sections of the accelerator where vacuum gauges are not frequent, such as the arcs. The problem has been addressed by means of FLUKA simulations and the results have been benchmarked with direct measurements performed in the LHC in 2011.

MOPPR087	Transverse Beam Emittance Measurements of a 16 MeV Linac at the Idaho Accelerator Center	electron, emittance, linac, background	990
	S. Setiniyaz, T.A. Forest ISU, Pocatello, Idaho, USA K. Chouffani, Y. Kim IAC, Pocatello, IDAHO, USA A. Freyberger JLAB, Newport News, Virginia, USA
	A beam emittance measurement of the 16 MeV S-band High Repetition Rate Linac (HRRL) was performed at Idaho State University's Idaho Accelerator Center (IAC). The HRRL linac structure was upgraded beyond the capabilities of a typical medical linac so it can achieve a repetition rate of 1 kHz. Measurements of the HRRL transverse beam emittance are underway that will be used to optimize the production of positrons using HRRL's intense electron beam on a tungsten converter. In this paper, we describe a beam imaging system using on an OTR screen and a digital CCD camera, a MATLAB tool to extract beamsize and emittance, detailed measurement procedures, and the measured transverse emittances for an arbitrary beam energy of 15 MeV.

MOPPR092	SVD-BASED METHOD FOR MEASUREMENT OF BEAM PARAMETERS AND FLAG RESOLUTION	emittance, simulation, booster, focusing	999
	G.M. Wang, R.P. Fliller, I. Pinayev, T.V. Shaftan BNL, Upton, Long Island, New York, USA
	In NSLS II booster to storage ring transport line, the typical beam size in vertical plane is ~60 μm, which requires very high flag resolution to get good beam parameters measurement. This paper describes a new SVD-based method to measure transverse beam parameters and flag resolution simultaneously with double quads scan. Implementation simulations of the proposed method are performed for a dispersion free region in the NSLS-II booster to storage ring transport line. With this method, it breaks the limitation of beam parameters measurement accuracy duo to the flag resolution.

TUXA03	Increasing the AGS Beam Polarization with 80 Tune Jumps	resonance, polarization, emittance, closed-orbit	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]

TUOAA03	Tests of Low Emittance Tuning Techniques at SLS and DAΦNE	emittance, coupling, alignment, collider	1065
	S.M. Liuzzo, M.E. Biagini, P. Raimondi INFN/LNF, Frascati (Roma), Italy M. Aiba Paul Scherrer Institut, Villigen, Switzerland M. Böge PSI, Villigen, Switzerland
	The SuperB collider design is based on extremely low emittances, comparable to those of synchrotron light sources. A Low Emittance Tuning (LET) algorithm was developed for SuperB and has been tested last year at DIAMOND. This paper will report on the results of the application of LET to SLS (PSI) and DAΦNE (LNF) in order to compare and confirm the previous results. In this tests, the correction of orbit, dispersion and coupling is applied simultaneously to the detection of Beam Position Monitors tilts. The effect of beam based alignment at DAΦNE is also presented, together with an evaluation of the effects of other possible sources of emittance growth.
	Slides TUOAA03 [4.313 MB]

TUOBA03	H⁻ and Proton Beam Loss Comparison at SNS Superconducting Linac	proton, linac, ion, DTL	1074
	A.P. Shishlo, A.V. Aleksandrov, J. Galambos, M.A. Plum ORNL, Oak Ridge, Tennessee, USA E. Laface ESS, Lund, Sweden V.A. Lebedev Fermilab, Batavia, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. A comparison of beam loss in the superconducting part (SCL) of the Spallation Neutron Source (SNS) linac for H⁻ and protons is presented. During the experiment the nominal beam of negative hydrogen ions in the SCL was replaced by a proton beam created by insertion of a thin stripping carbon foil placed in the low energy section of the linac. The observed significant reduction in the beam loss for protons is explained by a domination of the intra-beam stripping mechanism of the beam loss for H-. The details of the experiment are discussed, and a preliminary estimation of the cross section of the reaction H⁻ + H⁻ -> H⁻ + H⁰ + e is presented.
	Slides TUOBA03 [0.772 MB]

TUPPC001	Quadrupole Shapes	optics, TRIUMF, controls, multipole	1149
	R.A. Baartman TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Traditionally, quadrupoles are shaped to have a constant vertical cross-section. In other words, the poles are cylindrical segments extended in the beam direction and circular or hyperbolic in cross section. At the ends, the poles are simply truncated or sometimes slightly smoothed with a chamfer. Even very short quadrupoles are often this shape. A new shape is derived analytically, and it is demonstrated that this shape yields dramatically smaller aberrations.

TUPPC003	Analytical Methods for Statistical Analysis for the Correction of Coupling Due to Errors	coupling, emittance, sextupole, betatron	1152
	A. Chancé, J. Payet CEA/DSM/IRFU, France B. Dalena CEA/IRFU, Gif-sur-Yvette, France
	The statistical evaluation of the coupling induced by magnets errors and misalignments on the optics design of a machine are done by tracking and Monte Carlo methods. These techniques are CPU demanding and time consuming. During the preliminary optics design phase a faster technique can be useful to evaluate the order of magnitude and the effectiveness of the correction system. Analytical expression for the transport along the machine of the magnets errors and misalignment are derived at first order. A perturbative approach is used to take into account the effect of a non zero central trajectory in the multipoles. The coupling correction is obtained by minimizing the cross-talk central trajectory matrix response.

TUPPC018	Estimation of Orbit and Optics Distortion of SuperKEKB by Tunnel Deformation	emittance, optics, coupling, luminosity	1197
	A. Morita, H. Koiso, Y. Ohnishi, K. Oide, H. Sugimoto KEK, Ibaraki, Japan
	The tunnel which was used for the KEKB B-factory is reused for the accelerator tunnel of the SuperKEKB. The total vertical displacement of the tunnel subsidence reached almost 30mm during 10 years KEKB operation. In order to operate the SuperKEKB which might be more delicate machine than the previous KEKB B-factory, we are evaluating the optics distortion by the tunnel deformation and studying the machine performance after the orbit and optics correction. We report the estimation of the machine performance degradation by the tunnel subsidence and the requirement of the correction.

TUPPC023	Waist Corrections at the Interaction Point of ATF2 in the Presence of IPBSM Fringe Rotations and Input Beam Sigma13, Sigma24	sextupole, coupling, simulation, alignment	1212
	S. Bai, J. Gao IHEP, Beijing, People's Republic of China P. Bambade LAL, Orsay, France
	The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. In beam tuning towards the goal beam size, the presence of a tilt of the IP Shintake monitor fringe pattern with respect to the x-y coordinate system of the beam (or equivalently a σ13 correlation), as well as a σ24 correlation, can break the orthogonality in the main σ34 and σ32 waist corrections during the minimization and result in larger vertical beam sizes at IP. Both effects are studied, analytically and in simulation, and a practical procedure is suggested for diagnosing the presence of a residual fringe tilt, by measuring the influence of the horizontal waist correction on the minimum vertical beam size.

TUPPC027	Multi Objective Genetic Optimization for Linac Lattice of PAL XFEL	linac, lattice, electron, emittance	1224
	C.H. Yi, M.-H. Cho, S.H. Kim, W. Namkung POSTECH, Pohang, Kyungbuk, Republic of Korea H.-S. Kang PAL, Pohang, Kyungbuk, Republic of Korea K.-J. Kim ANL, Argonne, USA
	Funding: Work supported by MEST and POSTECH Physics BK21 Program. There are a large number of variables and objectives in design of XFEL linac lattices. Recently, most of accelerator physics field, are applying the multi-objective genetic algorithm (MOGA) for these kinds of problems. MOGA was applied to the PAL XFEL linac lattice design. Longitudinal position of all components was fixed before applying MOGA. RF parameters of RF cavities and bending angles of bunch compressors are selected as variables. Various beam parameters computed by ELEGANT were used as objectives. By using MOGA, new linac lattice designs with 2 and 3 bunch compressors was generated and their beam properties are presented in this paper.

TUPPC033	Random Walk Optimization in Accelerators: Vertical Emittance Tuning at SLS	target, emittance, luminosity, controls	1230
	M. Aiba, M. Böge, N. Milas, A. Streun Paul Scherrer Institut, Villigen, Switzerland
	The operation of a high performance accelerator is realized only when several beam based corrections are implemented. These corrections are, however, limited by measurement errors as the correction approaches the ideal value. To overcome this limitation, we investigate the application of a random walk (RW) optimization specifically to minimize the vertical emittance at the SLS. A systematic minimization is performed by measuring linear coupling and spurious vertical dispersion and correcting them using 36 skew quadrupole correctors. On the other hand, the minimization can be performed by simply applying a multi-variable optimization from the mathematics point of view, where the best combination of skew corrections is to be found. The measured vertical beam size is available as a stable target function of the minimization even at very low vertical emittance. Although RW and other algorithms are implemented into various accelerator computer codes, it is interesting to apply this concept to the real machine, where measurement errors are unavoidable and may prohibit systematic minimization based on a machine model. Possible applications of the technique in general are also discussed.

TUPPC035	Design of a Surface Muon Beam Line for High Field muSR at the PSI Proton Accelerator Facility	simulation, focusing, proton, secondary-beams	1236
	D. Reggiani, K. Deiters, P. Kaufmann, Y. Lee, T. Prokscha, T. Rauber, R. Scheuermann, K. Sedlak, V. Vranković Paul Scherrer Institut, Villigen, Switzerland
	Starting from 2012, a high field muSR (muon spin rotation/relaxation/resonance) facility will come into operation in the piE3 secondary beam line located at the target station E of the PSI proton accelerator. For this purpose, the last part of the beam line has been redesigned in order to integrate two electrostatic spin rotator devices providing a 90° rotation of the muon spin. At the same time, requirements of small beam diameter (σ ≈ 10 mm) as well as small momentum bite (δ_p/p ≈ 1%) in the sample region have to be met. This work focuses on the simulation of the beam optics (28 MeV/c design momentum). Particular concern is given to potential transmission losses caused by the spin rotator devices. The matching of the beam line with the high magnetic field up to 9.5 T surrounding the sample region has been considered as well. An overview of the spin rotator devices, specifically designed for this project, is also presented.

TUPPC036	Integration with the LHC of Electron Interaction Region Optics for a Ring-ring LHeC	proton, dipole, electron, optics	1239
	L.N.S. Thompson Cockcroft Institute, Warrington, Cheshire, United Kingdom R. Appleby UMAN, Manchester, United Kingdom N.R. Bernard ETH, Zurich, Switzerland H. Burkhardt, B.J. Holzer CERN, Geneva, Switzerland M. Fitterer KIT, Karlsruhe, Germany M. Klein The University of Liverpool, Liverpool, United Kingdom P. Kostka DESY Zeuthen, Zeuthen, Germany
	The Large Hadron Electron Collider (LHeC) project is a proposal to study e-p and e-A interactions at the LHC. One design uses an electron synchrotron to collide a 60GeV e± beam with the 7TeV proton beam. Designing a new accelerator around the existing LHC machine poses unique challenges, particularly in the interaction region (IR). The electron beam must be quickly separated from the proton beam after the interaction point (IP) to avoid beam-beam effects, while not significantly reducing luminosity or producing large amounts of synchrotron radiation. The proton beam must pass through the electron optics, while the electron beam must avoid the proton optics. The long straight section requires bending in both planes to counteract the IP crossing angle and to displace the beam vertically from the electron machine to the proton IP. An achromatic bending scheme is used in the vertical plane to eliminate dispersion at the IP and provide an optics which is well matched to the LHeC ring lattice. The interaction region and long straight section design is presented and detailed, and the design process and principles discussed.

TUPPC038	Interaction Region Optics for the Non-Interacting LHC Proton Beam at the LHeC	proton, electron, optics, synchrotron	1245
	L.N.S. Thompson Cockcroft Institute, Warrington, Cheshire, United Kingdom R. Appleby UMAN, Manchester, United Kingdom O.S. Brüning, B.J. Holzer CERN, Geneva, Switzerland M. Klein The University of Liverpool, Liverpool, United Kingdom P. Kostka DESY Zeuthen, Zeuthen, Germany
	The Large Hadron Electron Collider project is a proposal to study e-p and e-A interactions at the LHC. Two electron accelerator designs are being studied; a linac and a synchrotron. In the synchrotron option, a 60GeV electron beam is collided with one of the LHC proton beams to provide high luminosity TeV-scale interactions. The interaction region for this scheme is complex and introduces a series of challenges due to the integration of the two machines. One of these is the optics of the second non-interacting proton beam. The second proton beam must not interfere with the LHeC experiment, but simultaneous running of the remaining LHC experiments requires that this beam must still circulate relatively undisturbed. This paper discusses methods to solve these challenges for the electron synchrotron design.

TUPPC039	Synchrotron Radiation Studies for a Ring-Ring LHeC Interaction Region and Long Straight Section	dipole, electron, proton, synchrotron	1248
	L.N.S. Thompson Cockcroft Institute, Warrington, Cheshire, United Kingdom R. Appleby UMAN, Manchester, United Kingdom N.R. Bernard ETH, Zurich, Switzerland O.S. Brüning, B.J. Holzer CERN, Geneva, Switzerland M. Klein The University of Liverpool, Liverpool, United Kingdom P. Kostka DESY Zeuthen, Zeuthen, Germany B. Nagorny DESY, Hamburg, Germany
	The Large Hadron Electron Collider project is a proposal to study e-p and e-A interactions at the LHC. In the design for an electron synchrotron (alternative designs for a linac are also under development), a 60GeV e± beam is collided with a 7TeV LHC proton beam to produce TeV-scale collisions. Despite being much lower energy than the proton beam, the electron beam is high enough energy to produce significant amounts of synchrotron radiation (SR). This places strong constraints on beam optics and bending. In particular challenges arise with the complex geometry required by the long straight section (LSS) and interaction region (IR). This includes the coupled nature of the proton and electron optics, as SR produced by the electron beam must not be allowed to quench the superconducting proton magnets or create problems with beam-gas backgrounds. Despite this, the electron beam must be deflected significantly within the IR to produce sufficient separation from the proton beam.

TUPPC041	A 3 TeV Muon Collider Lattice Design	emittance, lattice, dipole, collider	1254
	Y. Alexahin, E. Gianfelice-Wendt Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy A new lattice for 3 TeV c.o.m. energy with β^=5mm was developed which follows the basic concept of the earlier 1.5 TeV design but uses quad triplets for the final focus in order to keep the maximum magnet strength and aperture about the same as in 1.5 TeV case. Another difference is employment of combined-function magnets with the goal to lower heat deposition in magnet cold mass and to eliminate regions without bending field which produce “hot spots” of neutrino radiation that can be an issue at higher energy. The proposed lattice is shown to satisfy the requirements on luminosity, dynamic aperture and momentum acceptance. * Y.Alexahin, E.Gianfelice-Wendt, A.Netepenko, Proc. IPAC10, Kyoto, May 2010, p. 1563

TUPPC042	Effect of Field Errors in Muon Collider IR Magnets on Beam Dynamics	multipole, dipole, sextupole, dynamic-aperture	1257
	Y. Alexahin, E. Gianfelice-Wendt, V.V. Kapin Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy In order to achieve peak luminosity of a Muon Collider (MC) in the 10³⁵/cm²/s range very small values of beta-function at the interaction point (IP) are necessary (β^* ~ 5 mm) while the distance from IP to the first quadrupole can not be made shorter than ~6m as dictated by the necessity of detector protection from backgrounds. In the result the beta-function at the final focus quadrupoles can reach 100 km making beam dynamics very sensitive to all kind of errors. In the present report we consider the effects on momentum acceptance and dynamic aperture of multipole field errors in the body of IR dipoles as well as of fringe-fields in both dipoles and quadrupoles in the case of 1.5 TeV (c.o.m.) MC. Analysis shows these effects to be strong but correctable with dedicated multipole correctors.

TUPPC044	Emittance and Phase Space Tomography for the Fermilab Linac	emittance, linac, focusing, optics	1263
	C. Johnstone, F.G.G. Garcia, T. Kobilarcik, G.M. Koizumi, C.D. Moore, D.L. Newhart Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Dept. of Energy. The Fermilab Linac delivers a variable intensity, 400-MeV beam to the The MuCool Test Area experimental hall via a beam line specifically designed to facilitate measurements of the Linac beam emittance and properties. A 10 m, dispersion-free and magnet-free straight utilizes an upstream quadrupole focusing triplet in combination with the necessary in-straight beam diagnostics to fully characterize the transverse beam properties. Since the Linac does not produce a strictly elliptical phase space, tomography must be performed on the profile data to retrieve the actual particle distribution in phase space. This is achieved by rotating the phase space distribution using different waist focusing conditions of the upstream triplet and performing a de-convolution of the profile data. Preliminary measurements using this diagnostic section are reported here.

TUPPC047	New Storage Ring Lattice for the Duke FEL Wiggler Switchyard System	wiggler, lattice, FEL, storage-ring	1272
	H. Hao, J.Y. Li, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA
	Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033. The Duke storage ring is a dedicated drive for the OK-4 FEL and OK-5 FEL, and for the state-of-the-art Compton gamma-ray source, High Intensity Gamma-Ray Source (HIGS). To produce FEL lasing below 190 nm and gamma-ray beams above 100 MeV, the FEL system needs to be upgraded by adding two helical OK-5 wigglers to increase the FEL gain with four OK5 wigglers for the VUV operation. To simultaneously preserve the linear polarization capability of the gamma-ray beam produced by the planar OK-4 FEL, a wiggler switchyard system is under development which will enable the switch between two planar OK-4 wigglers and two helical OK-5 wigglers in the middle of the FEL straight. In this work, we present the new magnetic lattice designed for the operation of the wiggler switchyard system. This new lattice is developed with great flexibility for the operation with different numbers of FEL wigglers, variable betatron tunes, and adjustable electron beam sizes at the collision point for the HIGS. In addition, the new lattice is developed for the operation in a wide range of energies, from 280 MeV to 1.2 GeV, with proper nonlinear dynamics compensations in order to realize a large dynamic aperture.

TUPPC050	Beam Transport and Storage with Cold Neutral Atoms and Molecules	sextupole, solenoid, injection, multipole	1281
	P.L. Walstrom, M.D. Di Rosa LANL, Los Alamos, New Mexico, USA
	Funding: US Department of Energy Paramagnetic neutral atoms and molecules are subject to magnetic-field-gradient forces on their magnetic moments. Li atoms and CaH molecules both have an effective magnetic moment of about one Bohr magneton, and in the presence of a strong (~1 T) magnetic field, acquire a Zeeman energy of one of two values, ±μ\|B\|. Particles with positive (negative) energy are repelled by (attracted toward) increasing fields. Li and CaH can be laser-cooled to speeds of tens of m/s and the corresponding magnetic fields needed for transport and injection are on the order of 1 T. The stable stored state is the field-repelled state. Many concepts of accelerator physics apply to our neutral particles. The analog of charge-exchange injection into storage rings is laser-based optical pumping from a field-seeking state to a field-repelled state. The role of dipoles in charged-particle optics is played by quadrupoles in neutral particle optics, and the role of quadrupoles by sextupoles. We present our design and tracking results for a neutral atom/molecule accumulator including an injection chicane with a laser-stimulated state-flip.

TUPPC051	FACET Tolerances for Static and Dynamic Misalignment	plasma, sextupole, simulation, wakefield	1284
	J.T. Frederico, M.J. Hogan, T.O. Raubenheimer SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515. The Facility for Advanced Accelerator and Experimental Tests (FACET) at the SLAC National Accelerator Laboratory is designed to deliver a beam with a transverse spot size on the order of 10 μm x 10 μm in a new beamline constructed at the two kilometer point of the SLAC linac. Commissioning the beamline requires mitigating alignment errors and their effects, which can be significant and result in spot sizes orders of magnitude larger. Sextupole and quadrupole alignment errors in particular can introduce errors in focusing, steering, and dispersion which can result in spot size growth, beta mismatch, and waist movement. Alignment errors due to static misalignments, mechanical jitter, energy jitter, and other physical processes can be analyzed to determine the level of accuracy and precision that the beamline requires. It is important to recognize these effects and their tolerances in order to deliver a beam as designed.

TUPPC054	Beam Acceleration by a Multicell RF Cavity Structure Proposed for Improved Yield in Hydroforming	cavity, electron, acceleration, focusing	1293
	J.A. Holmes, Y.W. Kang ORNL, Oak Ridge, Tennessee, USA A.E. Fathy, K.R. Shin University of Tennessee, Knoxville, Tennessee, USA
	Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. We study the accelerating properties of a new multicell cavity structure with irises forming a rectangular aperture between the cavity cells. We are interested in this structure because, from a mechanical point of view, the rectangular iris may make possible a much improved structure quality using a hydroforming manufacturing process. RF analysis shows that the rectangular iris shape provides asymmetric transverse focusing per half RF period. If the horizontal and vertical rectangular irises are interleaved, the net transverse focusing can be increased. The present studies of the acceleration and transport properties of these cavities are conducted by tracking particles through time-dependent 3D cavity fields from CST MWS using the ORBIT Code.

TUPPC055	Development of an Automatic MATLAB based Emittance Measurement Tool for the IAC Accelerators	emittance, EPICS, background, controls	1296
	C.F. Eckman, A. Andrews, Y. Kim, S. Setiniyaz, D.P. Wells IAC, Pocatello, IDAHO, USA A.W. Hunt ISU, Pocatello, Idaho, USA
	At the Idaho Accelerator Center (IAC) of Idaho State University, we have been operating fifteen low energy accelerators. To optimize those accelerators properly, we have to measure the transverse beam emittance. To measure the transverse beam emittance of an S-band linear accelerator with the quadrupole scan technique, we installed an Optical Transition Radiation (OTR) screen and a digital CCD camera in the bealime of the accelerator. From the images of the digital CCD camera, the transverse beam profile on the OTR screen can be acquired. To extract the transverse beam size and to estimate the transverse emittance, we have developed a MATLAB program. This paper describe the details of the MATLAB program and performance of our MATLAB based emittance measurement tool.

TUPPC056	Optics Measurements and Corrections at RHIC	optics, proton, luminosity, lattice	1299
	M. Bai, J.N. Aronson, M. Blaskiewicz, Y. Luo, V.H. Ranjbar, G. Robert-Demolaize, S.M. White BNL, Upton, Long Island, New York, USA G. Vanbavinckhove CERN, Geneva, Switzerland
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The further improvement of RHIC luminosity performance requires more precise understanding of the RHIC modeling. Hence, it is necessary to minimize the beta-beat, deviation of measured beta function from the calculated beta functions based on an model. The correction of beta-beat also opens up the possibility of exploring operating RHIC polarized protons at a working point near integer, a preferred choice for both luminosity as well as beam polarization. The segment-by-segment technique for reducing beta-beat demonstrated in the LHC operation for reducing the beta-beat was first tested in RHIC during its polarized proton operation in 2011. It was then fully implemented during the RHIC polarized proton operation in 2012. This paper reports the commissioning results. Future plan is also presented.

TUPPC059	Extraction of the Lie Map from Realistic 3D Magnetic Field Map	dipole, extraction, dynamic-aperture, lattice	1308
	Y. Li BNL, Upton, Long Island, New York, USA X. Huang SLAC, Menlo Park, California, USA
	Funding: Supported by Department of Energy Contract No. DE-AC02-98CH10886. We present a method to extract the Lie map of any arbitrary accelerator magnet from its actual 3D field map. After fitting a Taylor map from multi-particle tracking trajectories through the actual field, we factorize the map into a Lie map using Dragt-Finn's method. This method is validated by comparing with COSY-infinity for a soft-edge quadrupole model. Applications of extracting symplectic maps for the SPEAR and NSLS-II dipoles are shown as examples. A comparison of the map-tracking results against the direct field-integration-based method also is given.

TUPPC060	Beam Optics and the pp2pp Setup of the STAR Experiment at RHIC	proton, simulation, optics, scattering	1311
	P.H. Pile, W. Guryn, J.H. Lee, S. Tepikian, K. Yip 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. The newly installed forward detector system at the STAR experiment at RHIC measures small angle elastic and inelastic scattering of polarized protons on polarized protons. The detector system makes use of a pair of Roman Pot (RP) detectors, instrumented with silicon detectors, and located on either side of the STAR intersection region downstream of the DX and D0 dipoles and quadrupole triplets. The parallel to point optics is designed so that scattering angles are determined from position measurements at the RP's with small error. The RP setup allows measurement of position and angle for a subset of the scattered protons. These measured position/angle correlations at the RP's can be compared with optics model predictions to get a measure of the accuracy of the quadrupole triplet current settings. The current in each quadrupole in the triplets is comprised of sums and differences of up to six power supplies and an overall 1% error in the triplet field strengths results in a 4% error in four-momentum transfer squared. This technique is also useful to check the polarity of the skew elements located in each quadrupole triplet. Results of the analysis will be presented.

TUPPC061	Commissioning of a beta∗ Knob for Dynamic IR Correction at RHIC	optics, luminosity, feedback, insertion	1314
	G. Robert-Demolaize, A. Marusic, S. Tepikian, S.M. White 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. In addition to the recent optics correction technique demonstrated at CERN and applied at RHIC, it is important to have a separate tool to control the value of the beta functions at the collision point (beta∗). This becomes even more relevant when trying to reach high level of integrated luminosity while dealing with emittance blow-up over the length of a store, or taking advantage of compensation processes like stochastic cooling. Algorithms have been developed to allow modifying independently the beta function in each plane for each beam without significant increase in beam losses. The following reviews the principle of such algorithms and their experimental implementation as a dynamic beta-squeeze procedure.

TUPPC063	The AGS Synchrotron with Four Helical Magnets	injection, resonance, betatron, optics	1320
	N. Tsoupas, H. Huang, W.W. MacKay, T. Roser, D. Trbojevic BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the US Department of Energy. The idea of using two partial helical magnets was applied successfully to the AGS synchrotron, to preserve the proton beam polarization. In this paper we explore in details the idea of using four helical magnets placed symmetrically in the AGS ring. This modification provides many advantages over the present setup of the AGS that uses two partial helical magnets. First, the symmetric placement of the four helical magnets allows for a better control of the AGS optics with reduced values of the beta functions especially near beam injection, second, the vertical spin direction during beam injection and extraction is closer to vertical, and third, it provides a larger “spin tune gap” for the placement of both the vertical and horizontal tunes of the AGS during acceleration, second. Although the same spin gap can be obtained with two partial helices of equal strength, the required strength of the two helices makes it impractical. In this paper we will provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and comparison of these results with the present setup of the AGS that uses two partial helical magnets. T. Roser et al., Proc. EPAC04, p. 1577 (2004). H. Huang et al., PRL 99, 154801(2007). * N. Tsoupas et. al., these proceedings.

TUPPC069	Third-Order Apochromatic Drift-Quadrupole Beamline	betatron, beam-transport, resonance, focusing	1329
	N. Golubeva, V. Balandin, R. Brinkmann, W. Decking DESY, Hamburg, Germany
	We have shown that for every drift-quadrupole system there exists an unique set of Twiss parameters (apochromatic Twiss parameters), which will be transported through that system without first order chromatic distortions. In this paper we continue the development of the theory of apochromatic focusing and present the design of a straight drift-quadrupole system which can transport apochromatic beam ellipses without influence not only of the second but also of the third order chromatic and geometric aberrations of the beamline transfer map. V.Balandin, R.Brinkmann, W.Decking, N.Golubeva. Apochromatic Beam Transport in Drift-Quadrupole Systems. Proceedings of IPAC'10, Kyoto, Japan.

TUPPC070	Alternating Spin Aberration Electrostatic Lattice for EDM Ring	lattice, simulation, proton, storage-ring	1332
	Y. Senichev, R. Maier, D. Zyuzin FZJ, Jülich, Germany M. Berz MSU, East Lansing, Michigan, USA
	The idea of the electric dipole moment search using the storage ring (SrEDM) with polarized beam is realized under condition of the long-time spin coherency of all particles, the time during which the RMS spread of the spin orientation of all particles in the bunch reaches one radian. Following the requirements of the planned EDM experiment, the SCT should be more than 1000 seconds. During this time each particle performs about 10⁹ turns in the storage ring moving on different trajectories through the optics elements. At such conditions the spin-rotation aberrations associated with various types of space and time dependent nonlinearities start to play a crucial role. In this paper we consider a new method based on the alternating spin drift, causing it to rotate alternately, thereby limiting the growth of aberrations at one order of magnitude lower. As a result, using this method we can achieve the SCT of the order of 5000-6000 seconds. The difficulties of these studies are still in the fact that the aberrations growth observed in the scale of a 10⁹ turns. For the study we use an analytical method in composition with a numerical simulation by COSY Infinity.

TUPPC071	Comparison of Different Numerical Modelling Methods for Beam Dynamics in Electrostatic Rings	simulation, lattice, optics, proton	1335
	D. Zyuzin, R. Maier, Y. Senichev FZJ, Jülich, Germany S.N. Andrianov, A.N. Ivanov St. Petersburg State University, St. Petersburg, Russia M. Berz MSU, East Lansing, Michigan, USA
	To search the electric dipole moment was proposed to use polarized protons at the so-called "magic" momentum of 0.7 GeV/c in an electric storage ring. For studying beam dynamics in electrostatic rings different computational methods can be used. We used differential algebra methods realized in COSY Infinity and integrating program with symplectic Runge-Kutta methods. These methods were observed and compared for orbital and spin motion.

TUPPC072	Modeling of Matching Channel for Accelerator Complexes	controls, lattice, booster, dipole	1338
	E.A. Podzyvalov, S.N. Andrianov St. Petersburg State University, St. Petersburg, Russia D. Zyuzin FZJ, Jülich, Germany
	Practically modern accelerator facility can be considered as a composite machines. Therefore it is necessary to consider special matching channels to joint all accelerator components together. For such channels advance various requirements, which can be formulated in the form of criteria sets. In this paper considered a global optimization concept allows to find appropriate solutions sets. This approach is demonstrated on the problem of modeling the matching channels for NICA accelerator complex.

TUPPC079	Tracking LHC Models with Thick Lens Quadrupoles: Results and Comparisons with the Standard Thin Lens Tracking	lattice, simulation, optics, dipole	1356
	M. Giovannozzi, H. Burkhardt, T. Risselada CERN, Geneva, Switzerland
	So far, the massive numerical simulation studies of the LHC dynamic aperture were performed using thin lens models of the machine. This approach has the clear advantage of speed, but it has also the disadvantage of requiring re-matching of the optics from the real thick configuration to the thin one. Furthermore, as the figure-of-merit for the re-matching is the agreement between the beta-functions for the two model, while the quadrupole gradients are left free parameters, the effect of the magnetic multipoles might be affected by this approach and in turn the dynamic aperture computation. In this paper the new approach is described and the results for the dynamic aperture are compared with the old approach, including detailed considerations on the CPU-time requirements.

TUPPC101	A Model of the AGS Based on Stepwise Ray-Tracing Through the Measured Field Maps of the Main Magnets	resonance, sextupole, focusing, simulation	1395
	Y. Dutheil, F. Méot, N. Tsoupas 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. Two dimensional mid-plane magnetic field maps of two of the main AGS magnets were produced, from Hall probe measurements, for a series of different current settings. The analysis of these data yielded the excitation functions and harmonic coefficients of the main magnets [BNL TN 424 & TN 429] which have been used so far in all the models of the AGS. The constant increase of computation power makes it possible today to directly use stepwise ray-tracing through these measured field maps with a reasonable computation time. We describe in detail how these field maps have allowed generation of models of the 6 different types of AGS main magnets, and how they are being handled with the Zgoubi ray-tracing code. We give and discuss a number of results so obtained regarding both beam and spin dynamics in the AGS, and provide comparisons with other numerical and analytical modeling methods.

TUPPD008	Recent Progress Toward a Muon Recirculating Linear Accelerator	linac, dipole, cryomodule, factory	1422
	K.B. Beard Muons, Inc, Batavia, USA M. Aslaninejad, C. Bonţoiu, A. Kurup, J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom S.A. Bogacz, V.S. Morozov, Y. Roblin JLAB, Newport News, Virginia, USA
	Both Neutrino Factories (NF) and Muon Colliders (MC) require very rapid acceleration due to the short lifetime of muons. After a capture and bunching section, a linac raises the energy to about 900 MeV, and is followed by one or more Recirculating Linear Accelerators (RLA), possibly followed by a Rapid Cycling Synchrotron (RCS) or Fixed-Field Alternating Gradient (FFAG) ring. A RLA reuses the expensive RF linac section for a number of passes at the price of having to deal with different energies within the same linac. Various techniques including pulsed focusing quadrupoles, beta frequency beating, and multipass arcs have been investigated via simulations to improve the performance and reduce the cost of such RLAs.

TUPPD011	Studies of the Twin Helix Parametric-resonance Ionization Cooling Channel with COSY INFINITY	simulation, resonance, emittance, collider	1428
	J.A. Maloney, K.B. Beard, R.P. Johnson Muons, Inc, Batavia, USA A. Afanasev GWU, Washington, USA S.A. Bogacz, Y.S. Derbenev, V.S. Morozov JLAB, Newport News, Virginia, USA B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA
	Funding: Supported in part by SBIR Grant DE-SC00005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A primary technical challenge to the design of a high luminosity muon collider is an effective beam cooling system. An epicyclic twin-helix channel utilizing parametric-resonance ionization cooling has been proposed for the final 6D cooling stage. A proposed design of this twin-helix channel is presented that utilizes correlated optics between the horizontal and vertical betatron periods to simultaneously focus transverse motion of the beam in both planes. Parametric resonance is induced in both planes via a system of helical quadrupole harmonics. Ionization cooling is achieved via periodically placed wedges of absorbing material, with intermittent rf cavities restoring longitudinal momentum necessary to maintain stable orbit of the beam. COSY INFINITY is utilized to simulate the theory at first order. The motion of particles around a hyperbolic fixed point is tracked. Comparison is made between the EPIC cooling channel and standard ionization cooling effects. Cooling effects are measured, after including stochastic effects, for both a single particle and a distribution of particles.

TUPPD020	An EMMA Racetrack	dipole, injection, extraction, electron	1452
	B.D. Muratori, J.K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom H.L. Owen UMAN, Manchester, United Kingdom
	EMMA (Electron Machine for Many Applications) is the world’s first prototype non-scaling electron FFAG hosted at Daresbury Laboratory. Several upgrade possibilities for EMMA are explored, from creating a dispersion-free region in the ring to facilitate injection and extraction to making an insertion in EMMA by turning it into a racetrack-style machine. Alternative methods of injection and extraction into the EMMA ring are explored together with their feasibility and implications. The option of developing nested racetracks to achieve a particular desired energy is also explored.

TUPPD021	Orbit Correction in the EMMA Non-scaling FFAG – Simulation and Experimental Results	closed-orbit, 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.

TUPPD026	Study of the RFQ Beam Cooler for SPES project	ion, rfq, emittance, extraction	1467
	M.M. Maggiore, A.M. Porcellato, S. Stark INFN/LNL, Legnaro (PD), Italy
	The SPES project is the new Radioactive Ion Beam facility under construction at Laboratori Nazionali of Legnaro, Italy. In this framework in order to improve the beam quality in terms of emittance and energy spread, a study of a new RFQ beam cooler device is accomplishing. The electromagnetic design of the RFQ section and the electrostatic layout of the injection and extraction regions have been done. The study about the beam dynamic is going on by means of dedicated codes which allow to take into account the interaction of the ions with the buffer gas needed to cool the beams. The status of the project and the results will be shown in this report.

TUPPD075	Simulated Performance of the Wisconsin Superconducting Electron Gun	emittance, solenoid, simulation, focusing	1572
	R.A. Bosch, K.J. Kleman UW-Madison/SRC, Madison, Wisconsin, USA R.A. Legg JLAB, Newport News, Virginia, USA
	The Wisconsin superconducting electron gun is modeled with multiparticle tracking simulations using the ASTRA and GPT codes. To specify the construction of the emittance-compensation solenoid, we studied the dependence of the output bunch's emittance upon the solenoid's strength and field errors. We also evaluated the dependence of the output bunch's emittance upon the bunch's initial emittance and the size of the laser spot on the photocathode. The results suggest that a 200-pC bunch with an emittance of about one mm-mrad can be produced for a free-electron laser.

TUPPP002	GLASS Study of the Canadian Light Source Storage Ring Lattice	dynamic-aperture, emittance, lattice, sextupole	1602
	W.A. Wurtz, L.O. Dallin CLS, Saskatoon, Saskatchewan, Canada
	GLASS is a technique for finding all potential operating points of a storage ring lattice by examining all possible configurations of the linear lattice. The Canadian Light Source (CLS) storage ring uses three quadrupole families, making it computationally efficient to use GLASS to study the lattice with unbroken symmetry. CLS does not employ harmonic sextupoles and has only two families of chromatic sextupoles. We can exhaust the sextupole degrees of freedom by requiring the horizontal and vertical chromaticities to be both zero. With no remaining free parameters in our lattice, it is possible to calculate dynamic aperture and momentum acceptance for select regions of interest uncovered by the GLASS scan. We find two regions with reasonable dynamic aperture and momentum acceptance: the region where we presently operate and a region that can be accessed by reversing the polarity of one quadrupole family.

TUPPP013	Effects of Multipoles in Dynamic Aperture of the ILSF Storage Ring	multipole, dynamic-aperture, sextupole, lattice	1632
	S. Fatehi, E. Ahmadi, F. Saeidi ILSF, Tehran, Iran D. Einfeld CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain H. Ghasem IPM, Tehran, Iran
	Dynamic aperture of a synchrotron light source shrinks to small value due to the multipole errors caused by magnet design. In the ILSF storage ring, the tolerance of magnets has been taken into account in the simulation and sextupole magnets reoptimized to improve the dynamic aperture. This paper yields the evaluated dynamic aperture include of multipole errors.

TUPPP014	HiSOR-II, Compact Light Source with a Torus-knot Type Accumulator Ring	lattice, emittance, insertion, insertion-device	1635
	A. Miyamoto, S. Sasaki HSRC, Higashi-Hiroshima, Japan
	Funding: This work is partially supported by Cooperative and Supporting Program for Researches and Educations in University sponsored by KEK. We proposed a torus knot type synchrotron radiation ring where the beam orbit is not closed with one turn but return to the starting position after multiple turns around the ring. This ring is capable of having many straight sections and it is advantageous for installation of insertion devices. We named this architecture AMATELAS. We are designing a new ring based on the shape of a (11, 3) torus knot for our future plan HiSOR-II. This ring has eleven 3.6-m-long straight sections though the ring diameter is as compact as 15 m. The achieved emittance is 17.4 nmrad with the lattice having bending magnets with combined function. This level of emittance is as low as the conventional 3rd generation light source. On the other hand, there is a potential problem caused by that the radius of the orbit and focusing force are not constant in the bending magnets. However, we confirmed that it does not make serious influence to the beam by calculating with dividing the bending into several sections. We will compare the parameters of this new ring with the conventional ring which we have designed as the future plan of our facility and evaluate performance as the compact synchrotron light source.

TUPPP022	Beam Optics Measurements during ALBA Commissioning	lattice, optics, emittance, storage-ring	1656
	M. Muñoz, G. Benedetti, J. Campmany, D. Einfeld, Z. Martí CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	The synchrotron light source ALBA is in the final stage of the Storage Ring commissioning, with the beamline commissioning well under way. This paper reviews the results of the modeling of the lattice and the agreement with the LOCO measurement of the machine; the performance of the beta beating correction (critical in the ALBA case due to the large gradient in the bending magnet and the low number of quadrupole families), including effect of insertion devices; the lifetime measurement; tune scans; tune shift with horizontal amplitude; and the general agreement of the machine to the model using during the design. A brief summary of the modeling of the injector chain is included.

TUPPP025	Resurrection of RESOLVE at NSRRC Prepared for the First Turn Beam Steering of the TPS Commissioning	injection, storage-ring, controls, kicker	1665
	H.-P. Chang, H.H. Chen, P.C. Chiu, P.J. Chou, K.T. Hsu, S.J. Huang, Y.-C. Liu, F.H. Tseng NSRRC, Hsinchu, Taiwan
	MATLAB based high level application software prepared for the 3GeV Taiwan Photon Source has been built and tested on the 1.5GeV Taiwan Light Source continuously. The RESOLVE program is surveyed and resurrected at NSRRC to support and help the first turn beam steering in the coming commissioning of the TPS accelerator complex. Due to the RESOLVE’s history, it contributed a lot in the past commissioning of SLC at SLAC National Accelerator Laboratory, we believe it may give help although most of the first turn beam steering of current light source machines may pass smoothly with well machine construction. In order to make the revised RESOLVE working, not only the compiling problem but also some memory bugs have been fixed, the updated RESOLVE now can be run on PC/Linux and Mac/OSX computer systems. We are trying to apply and test it on the TLS SR with the turn-by-turn digital BPM system. Some exercises of the error finding in beam steering of the off-axis injection beam are performed for presentation.

TUPPP034	BPM Gains and Beta Function Measurement Using MIA and FPGA BPMs at the APS	betatron, lattice, optics, feedback	1686
	C.-X. Wang, G. Decker, H. Shang, C. Yao ANL, Argonne, USA D. Ji IHEP, Beijing, People's Republic of China
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The broadband BPM system at the Advanced Photon Source (APS) is being upgraded with FPGA-based beam history modules, which fix problems in the old history modules and increase functionality. Using these new turn-by-turn BPMs and the newly developed real-time feedback system, measurement of BPM gains, beta function and other optics functions are being developed based on model-independent analysis of turn-by-turn data and model fitting, aiming at quasi-real-time and high-accuracy optics measurement. We will discuss our effort, especially experience with strong nonlinearity and wakefields typical of 3rd-generation light sources.

TUPPP039	Vertical Dispersion Bump Design for Femto-second Slicing Beamline at the ALS	coupling, lattice, emittance, radiation	1698
	C. Sun, C. Steier, W. Wan LBNL, Berkeley, California, USA
	Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Femto-second (fs) slicing beamline has been brought to the operation at the Advanced Light Source (ALS) since 2002. It employs the resonant interaction of an electron bunch with a fs laser beam in a wiggler to energy-modulate a short section of the bunch. The induced energy modulation is then converted to a transverse displacement using a vertical dispersion bump downstream of the wiggler. Thus, the radiation from the fs pulse can be separated from the main bunch radiation. The current dispersion bump design has proved to be an effective and reliable one. However, the ALS storage ring lattice is under an upgrade to improve its brightness. After the completion of the upgrade, a new low emittance will be implemented, and the current dispersion bump design needs to be modified to provide the adequate vertical displacement, while minimizing the vertical emittance and spurious dispersion. In this paper, we present the new design of a vertical dispersion bump using Multi-Objective Genetic Algorithm (MOGA) for the ALS upgrade lattice.

TUPPP065	Progress Report on the SwissFEL Injector Test Facility	emittance, laser, optics, dipole	1747
	T. Schietinger, M. Aiba, S. Bettoni, B. Beutner, M. Csatari, K. Doshekenov, Y.-C. Du, M.W. Guetg, C.P. Hauri, R. Ischebeck, F. Le Pimpec, N. Milas, G.L. Orlandi, M. Pedrozzi, P. Peier, E. Prat, S. Reiche, B. Smit, A. Trisorio, C. Vicario Paul Scherrer Institut, 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. The RF photoinjector facility has been in operation since 2010 and has recently reached its design energy of 250 MeV. A newly installed movable magnetic chicane allows longitudinal bunch compression studies. We report on the first experience with the bunch compressor and present the latest results of projected and slice emittance measurements.
	Poster TUPPP065 [1.801 MB]

TUPPP069	A Compact, Modular Electron Beam Delay Line for Use in Novel Free-Electron Laser Schemes	undulator, FEL, electron, lattice	1759
	J.K. Jones, J.A. Clarke, N. Thompson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Two Free-Electron Laser (FEL) schemes have been proposed, for the generation of attosecond pulse trains* and for the improvement of the longitudinal coherence of SASE FELs*, in which repeated electron delays are implemented within the undulator lattice. To obtain the maximum performance and flexibility from these schemes it is advantageous to use an electron delay line that satisfies the isochronicity conditions, as well as being compact, modular and, ideally, variable. In this paper we present initial designs for such a system, along with simulations of its performance. We investigate both in-undulator and out-of-undulator designs, and compare the applicability of each for various aspects of the FEL design, as well as commenting on the mechanical and magnetic implications of the schemes. N.R. Thompson and B.W.J. McNeil. Phys. Rev. Lett. 100, 203901 (2008). ** N.R. Thompson, D.J. Dunning and B.W.J. McNeil, IPAC2010, TUPE050, p. 2257 (2010).

TUPPR006	Design Progress and Construction Status of SuperKEKB	dipole, status, wiggler, klystron	1822
	H. Koiso, K. Akai, K. Oide KEK, Ibaraki, Japan
	KEKB operation finished in June 2010, and the upgrade of KEKB to SuperKEKB has commenced. The design luminosity of SuperKEKB is 8×10³⁵cm^-2s^-1, which is 40 times higher than that of KEKB. The design strategy for SuperKEKB is based on the Nano-Beam Scheme, where the vertical beam sizes of the low-energy positron ring and the high-energy electron ring are squeezed to 50−60 nm at the interaction point with a large Piwinski angle. The beam currents in both rings will be double those in KEKB. Finalizing the design of the interaction region is going on by using precise modeling of beam optics. Dismantling KEKB rings and fabrication of accelerator components for SuperKEKB including magnets, power supplies, and antechamber-type beam pipes have already started. This paper describes design progress and construction status of SuperKEKB.

TUPPR022	Traditional Final Focus System for CLIC	luminosity, lattice, collider, linear-collider	1858
	H. Garcia, A. Latina, R. Tomás CERN, Geneva, Switzerland H. Garcia UPC, Barcelona, Spain
	Next generation linear colliders needs a very strong focalisation to reach nanometer beam size at the Interaction Point. This task and the chromatic correction generated by the strong lenses is done by the Final Focus System. A traditional Final Focus System based on dedicated chromaticity correction sections is presented as an alternative for CLIC Final Focus. The scheme of the lattice is shown and some tolerances in the Final Doublet are calculated. A systematic tuning using Simplex algorithm and sextupole knobs is performed. The complete comparison to the Local Chromaticity correction scheme is presented.

TUPPR023	Final-Focus Optics for the LHeC Electron Beam Line	synchrotron, radiation, synchrotron-radiation, electron	1861
	J.L. Abelleira EPFL, Lausanne, Switzerland J.L. Abelleira, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland H. Garcia UPC, Barcelona, Spain
	Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu- CARD, grant agreement no. 227579. One of the options considered for the ECFA-CERN-NuPECC design study for a Large Hadron electron Collider (LHeC)* based on the LHC is adding a recirculating energy-recovery linac tangential to the LHC. First designs of the electron Final Focus System have shown the need to correct the chromatic aberrations. Two designs using different approaches for the chromaticity correction are compared, namely, the local chromaticity correction** and the traditional approach using dedicated sections. LHeC Study Group, “A Large Hadron Electron Collider at CERN,” LHeC-Note 2011-001 (2011). *J. Abelleria et al., "Design Status of LHeC Linac‐Ring Interaction Region," IPAC2011, p. 2796 (2011).

TUPPR028	Recent Improvements in the Orbit Feedback and Ground Motion Mitigation Techniques for CLIC	luminosity, simulation, feedback, ground-motion	1876
	J. Snuverink, J. Pfingstner, D. Schulte CERN, Geneva, Switzerland
	The Compact Linear Collider (CLIC) accelerator has strong stability requirements on the position of the beam. In particular, the beam position will be sensitive to ground motion. A number of mitigation techniques have been proposed - quadrupole stabilization and positioning, final doublet stabilization as well as beam based orbit and interaction point (IP) feedback. Integrated studies of the impact of ground motion on the CLIC Main Linac (ML) and Beam Delivery System (BDS) that model the latest hardware designs have been performed. Furthermore, additional imperfections have been introduced and the robustness of this system is discussed in detail. The possibility of using ground motion measurements as an alternative to the quadrupole stabilization is investigated.

TUPPR031	Experimental Verification of the CLIC Decelerator with theTest Beam Line in the CLIC Test Facility 3	extraction, alignment, lattice, linac	1885
	R.L. Lillestøl, S. Döbert, M. Olvegård, A. Rabiller, G. Sterbini CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The Test Beam Line in the CLIC Test Facility 3 is the first prototype of the CLIC drive beam decelerator. The main purpose of the experiment is to demonstrate efficient 12 GHz rf power production and stable transport of an electron drive beam during deceleration. The Test Beam Line consists of a FODO structure with high precision BPMs and quadrupoles mounted on mechanical movers for precise beam alignment. Nine out of the planned 16 Power Extraction and Transfer Structures have currently been installed and commissioned. We correlate rf power production measurements with the drive beam deceleration measurements, and compare the two measurements to the theoretical predictions. We also discuss the impact of the drive beam bunch length and bunch combination on the measurements.

TUPPR034	Beam-based Alignment in CTF3 Test Beam Line	alignment, feedback, beam-losses, injection	1894
	G. Sterbini, S. Döbert, R.L. Lillestøl, E. Marín, D. Schulte CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The CLIC linear collider is based on the two beams acceleration scheme. During acceleration, the drive beam suffers a large increase in its energy spread. In order to efficiently transport such a beam, beam-based alignment techniques together with tight pre-alignment tolerances are crucial. A beam-based steering campaign has been conducted at the Test Beam Line of the CLIC Test Facility to evaluate the performance of several algorithms. In the following we present and discuss the obtained results.

TUPPR035	A Comparative Study for the CLIC Drive Beam Decelerator Optics	optics, injection, alignment, lattice	1897
	G. Sterbini, D. Schulte CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The baseline for the CLIC drive beam decelerators optics consists of a 2-m-long FODO cell. This solution was adopted to have strong focusing in order to mitigate the effect of the PETS wakefields and to minimize the drive beam envelope. Taking into account the most recent PETS design, we compare the performance of the baseline FODO cell with a proposal that consider twice longer FODO cell. Despite of the expected cost in term of performance, the reduction of the complexity of the system due to the halving of the number of quadrupoles can be beneficial for the overall optimization of the decelerator design.

TUPPR052	3D FEA Computation of the CLIC Machine Detector Interface Magnets	solenoid, simulation, shielding, luminosity	1936
	A. Bartalesi, M. Modena CERN, Geneva, Switzerland
	A critical aspect of the Compact Linear Collider (CLIC) design is represented by the Accelerator/Experiment interface (called Machine Detector Interface or MDI). In the 3 TeV CLIC layout, the final focus QD0 quadrupole will be located inside the end-cap of the detector itself. This complex MDI scenario required to be simulated with a full 3D-FE analysis. This study was critical to check and control the magnetic cross-talk between the Detector Solenoid and the final Focus QD0 magnet and therefore to optimize the design of an “antisolenoids” system needed to shield the QD0 and the e⁻/e⁺ beams from the detector magnetic field. In this paper the development and evolution of the computational FE model is presented together with the results obtained and their implication on the CLIC MDI Design.

TUPPR056	Parametric Study of the CLIC Damping Rings Delay Ring for Reaching Isochronicity Conditions	dipole, sextupole, damping, optics	1948
	P. Zisopoulos, F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland
	A delay ring in the CLIC damping rings complex is necessary for recombining the two trains to one with the nominal bunch separation of 0.5ns. The preservation of the longitudinal bunch distribution demands an optics design, which eliminates momentum compaction factor up to high order, allowing the delay ring to function under isochronous conditions. Taking into account thin lens approximation, a qualitative estimation of parameters of the cell that will be used in the delay ring, is given, so as to obtain isochronicity conditions. Considerations on the possibility of tuning the cell under those requirements are finally presented.

TUPPR060	Detection of Ground Motion Effects on the Beam Trajectory at ATF2	ground-motion, lattice, extraction, linear-collider	1954
	Y. Renier, J. Pfingstner, D. Schulte, R. Tomás CERN, Geneva, Switzerland
	The ATF2 experiment is currently demonstrating the feasibility of the beam delivery system for the future linear collider. The tunning is very critical to obtain the nanometer vertical beam size at the interaction point and in the case of CLIC, ground motion effects on the beam must be corrected. In this respect, as a proof of principle of a ground motion feed forward, the ground motion effects on the beam trajectory are extracted from the beam position monitor readings.

TUPPR068	The Achromatic Telescopic Squeezing Scheme: Basic Principles and First Demonstration at the LHC	optics, sextupole, injection, insertion	1978
	S.D. Fartoukh, R. De Maria, B. Goddard, W. Höfle, M. Lamont, G.J. Müller, L. Ponce, S. Redaelli, R.J. Steinhagen, M. Strzelczyk, R. Tomás, G. Vanbavinckhove, J. Wenninger CERN, Geneva, Switzerland R. Miyamoto ESS, Lund, Sweden
	The Achromatic Telescopic Squeezing (ATS) scheme [1] is a novel squeezing mechanism enabling the production of very low β^* in circular colliders. The basic principles of the ATS scheme will be reviewed together with its strong justification for the High-Luminosity LHC Project. In this context, a few dedicated beam experiments were meticulously prepared and took place at the LHC in 2011. The results obtained will be highlighted, demonstrating already the potential of the ATS scheme for any upgrade project relying on a strong reduction of β^. [1] S. Fartoukh, "An Achromatic Telescopic Squeezing (ATS) Scheme For The LHC Upgrade," IPAC'11, WEPC037, p. 2088 (2001).*

TUPPR075	Challenges for the Magnet System of LHeC	electron, proton, linac, dipole	1996
	S. Russenschuck, B.J. Holzer, G. Kirby, A. Milanese, R. Tomás, D. Tommasini, F. Zimmermann CERN, Geneva, Switzerland
	The main challenges for the normal conducting magnet system are the very compact, low field, and high precision magnets for the ring-ring option and their rapid installation in the crowded LHC tunnel. The superconducting triplet magnets require strong gradients for the protons in close vicinity of a field-free region for the electrons. The field requirements for the ring-ring option allow a number of different magnet designs using the well-proven Nb-Ti superconductor technology and making use of the cable development for the LHC. The separation distance between the electron and proton beams in Q1 requires a half-aperture quadrupole design to limit the overall synchrotron radiation power emitted by the bending of the electron beam. The requirements in terms of aperture and field gradient are more difficult to obtain for the Linac-Ring option. Consequently we present the limitations for the field gradient and septum size achievable with both Nb-Ti and Nb3Sn superconducting technologies.

TUPPR085	Recycler Chromaticities and End Shims for NOvA at Fermilab	lattice, sextupole, dynamic-aperture, dipole	2023
	M. Xiao Fermilab, Batavia, USA
	In era of NOvA operation, it is planned to slip-stack six on six Booster proton batches in the Recycler ring for a total intensity of 5×10¹³ protons/cycle. During the slip-stacking, the chromaticities are required to be jumped from (-2,-2) to (-20,-20). However, they can only be adjusted to (-12,-12) from (-2,-2) using existing 2 families of powered sextupoles. On the other hand, the presently designed Recycler lattice for Nova replaces the 30 straight section with 8 “D-D half FODO cells”. We use 3 quads in a half-cell to obtain the working point under the limit of the feasible quad strength, and the maximum beta-function in this section cannot be less than 80 m. In this paper, we re-designed the end shims of the permanent magnets in the ring lattice with appropriate quadrupole and sextupole components to meet both chromaticity and tune requirements. We are able to use 2 quads in a half cell in RR30 straight section within feasible quad strength. The maximum beta-functions are also lowered to around 55 m. The dynamic aperture tracking has been done using MAD to simulate the scenario of beam injection into the Recycler ring for Nova.

WEYA03	Overview of B-Factories	emittance, sextupole, injection, collider	2086
	M.E. Biagini INFN/LNF, Frascati (Roma), Italy
	An overview of the two recently approved high luminosity B-Factories, the SuperB in Italy and the SuperKEKB in Japan, will be presented. The main design features to reach the very high luminosity requested and a status of progress in design and construction will be given.
	Slides WEYA03 [6.151 MB]

WEOAA01	Injected Beam Imaging at SPEAR 3 with a Digital Optic Mask	injection, synchrotron, storage-ring, target	2116
	H.D. Zhang, R.B. Fiorito, A.G. Shkvarunets UMD, College Park, Maryland, USA W.J. Corbett, A.S. Fisher, K. Tian SLAC, Menlo Park, California, USA
	Funding: *This work is partially funded by the Office of Naval Research and the DOD Joint Technology Office. At SPEAR3, the light source operates in top-up injection mode with 273nC charge circulating in the storage ring (350mA). Each individual injection pulse contains only 40pC, or a contrast ration of 1:6800. In order to monitor injected beam dynamics during User operations, it is desirable to optically image the injected charge distribution on a turn-by-turn basis in the presence of the bright stored beam. The measurement is made by re-imaging visible synchrotron radiation onto a 1024x768 pixel Digital-Micro-Array mirror device (DMD) which is used to 'mask' light from the central stored beam while observing the weak injected beam signal on an intensified, fast-gated CCD camera. Complex beam dynamics are observed after only a few 10's of turns around the synchrotron. In this paper we report on the DMD optical configuration, masking considerations, measurement timing and initial tests imaging the injected beam in the presence of stored beam.
	Slides WEOAA01 [1.874 MB]

WEEPPB013	Direct Wind Superconducting Corrector Magnets for the SuperKEKB IR	dipole, octupole, background, multipole	2191
	B. Parker, M. Anerella, J. Escallier, A.K. Ghosh, A.K. Jain, A. Marone, P. Wanderer BNL, Upton, Long Island, New York, USA Y. Arimoto, M. Iwasaki, N. Ohuchi, M. Tawada, K. Tsuchiya, H. Yamaoka, Z.G. Zong KEK, Ibaraki, Japan
	Upgrade of the KEKB asymmetric e⁺e⁻ collider for a forty-fold luminosity increase, denoted SuperKEKB, is now underway. For SuperKEKB the beam crossing angle is increased to provide separate focusing channels for the incoming and outgoing electron and positrons beams in new superconducting Interaction Region (IR) magnets. Two functional classes of superconducting corrector magnets are needed to meet SuperKEKB beam optics goals. Dipole, skew-dipole, skew-quadrupole and octupole coil windings will be inserted inside the bores of the main IR quadrupoles to make magnet center alignments, roll adjustments and non-linear optics corrections. A second class of high-order magnetic multipole corrector coils is needed to compensate the non-linear fringe field experienced by the circulating beam that passes just outside the main quadrupole coils that are closest to the Interaction Point (IP). Near the IP there is no space for magnetic yokes or other passive shielding to diminish the fringe field. At the time of this conference the SuperKEKB corrector magnet production will be under way. The SuperKEKB correction coil design and our production technique are reviewed in this paper.

WEEPPB014	The Magnetic Model of the LHC during the 3.5 TeV Run	injection, dipole, controls, optics	2194
	E. Todesco, N. Aquilina, M. Giovannozzi, M. Lamont, F. Schmidt, R.J. Steinhagen, M. Strzelczyk, R. Tomás CERN, Geneva, Switzerland N.J. Sammut University of Malta, Information and Communication Technology, Msida, Malta
	The magnetic model of the LHC is based on a fit of the magnetic measurements through equations that model the field components (geometric, saturation, persistent) at different currents. In this paper we will review the main results related to the magnetic model during the run of the LHC in 2010-2011: with a top energy of 3.5 TeV, all components of the model but the saturation are visible. We first give an estimate of the reproducibility of the main components and multipolar errors as they can be deduced from beam measurements, i.e. orbit, tune, chromaticity, beta beating and coupling. We then review the main results relative to the decay at injection plateau, dependence on powering history, and snapback at the beginning of the ramp for both tune and chromaticity. We discuss the precision obtained in tracking the magnets during the ramp, where the persistent current components gradually disappear. We conclude by presenting the behaviour of the quadrupoles model during the squeeze. A list of the major changes implemented during the operation together with what are considered as the main open issues is given.

WEPPC030	Second Sound Measurement Using SMD Resistors to Simulate Quench Locations on the 704 MHz Single-cell Cavity at CERN	cavity, simulation, cryogenics, linac	2269
	K.C. Liao, O. Brunner, E. Ciapala, T. Junginger, W. Weingarten CERN, Geneva, Switzerland
	Oscillating superleak transducers (OSTs) containing a flexible porous membrane are widely used to detect the so-called second sound temperature wave when a quench event occurs in a superconducting RF cavity. In principle, from the measured speed of this wave and the travel time between the quench event and several OSTs, the location of the quench sites can be derived by triangulation. Second sound behavior has been simulated though different surface mount (SMD) resistors setups on a Superconducting Proton Linac (SPL) test cavity, to help understand the underlying physics and improve quench localisation. Experiments are described that have been conducted to search for explanation of heat transfer mechanism during cavity quench that causes contradictory triangulation results.
	Poster WEPPC030 [1.473 MB]

WEPPC033	RF and Surface Properties of Bulk Niobium and Niobium Film Samples	niobium, electron, collider, photon	2278
	T. Junginger, W. Weingarten CERN, Geneva, Switzerland R. Seviour University of Huddersfield, Huddersfield, United Kingdom C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Work supported by the German Doctoral Students program of the Federal Ministry of Education and Research (BMBF) The surface resistance Rs of superconducting cavities can be obtained from the unloaded quality factor Q0. Since RS varies strongly over the cavity surface its value must be interpreted as averaged over the whole cavity surface. A more convenient way to investigate the surface resistance of superconducting materials is therefore to examine small samples, because they can be manufactured cheaply, duplicated easily and used for further surface analyses. At CERN a compact Quadrupole Resonator has been developed for the RF characterization of superconducting samples at different frequencies. In this contribution, results from measurements on bulk niobium and niobium film on copper samples are presented. Different models accounting for the field depended surface resistance are being confronted by the experimental results. The RF results are being correlated to surface analyses measurements carried out on the same samples.

WEPPC037	A Ring-shaped Center Conductor Geometry for a Half-wave Resonator	impedance, cavity, linac, ion	2289
	B. Mustapha, Z.A. Conway, P.N. Ostroumov ANL, Argonne, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract DE-AC02-06CH11357. Half-wave resonators (HWR) are used and being proposed for the acceleration of high-intensity proton and heavy-ion beams in the 0.1 < β < 0.5 velocity range. The highest performing half-wave resonator geometries use a center conductor with a race-track shaped cross section in the high-electric field region; a feature shared with spoke cavities which are also being proposed for the same velocity regime. We here propose a ring-shaped center conductor instead of the race-track shape. Preliminary studies show that the ring geometry has a similar peak surface electric field as the race-track one, but has several other advantages. In particular, the ring-shaped geometry has: a lower peak surface magnetic field, a much higher Shunt impedance for the same peak fields, and no quadrupole electric field asymmetry which has been observed in the race-track geometry. In a solenoid-based symmetric focusing, the quadrupole component may lead to unnecessary emittance growth which is not acceptable in high-intensity ion linacs. We will present a detailed comparison and a discussion of the two geometries.

WEPPC044	Multipole Effects Study for Project X Front End Cavities	cavity, multipole, linac, focusing	2309
	P. Berrutti, M.H. Awida, I.V. Gonin, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev Fermilab, Batavia, USA
	Effects of RF field asymmetry along with multipoles have been studied in Project X front end cavities. One family of half wave resonators operating at 162.5 and two of spoke resonators operating at 325 MHz have been analysed. HWR and spoke resonators unlike elliptical cavities, do not have axial symmetry, hence a quadrupole perturbation to the beam is present. The purpose of this paper is to explain the approach and the calculation method used to understand and overcome the drawbacks due to the RF field asymmetry.

WEPPC053	SSR1 HOM Analysis and Measurements	HOM, dipole, cavity, higher-order-mode	2333
	M.H. Awida, P. Berrutti, I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE Single spoke resonators (SSR1, β=0.22) are currently under development for Project X at Fermilab. In this paper, extensive Higher Order Mode (HOM) analysis carried out on SSR1 is reported including the simulated R/Q for monopoles, dipoles, and quadrupoles. HOM measurements carried out on several spoke cavities are also reported including the harmonic response and the bead pull measurements. Comparison between the measured R/Q values and the simulated ones are presented.

WEPPD011	Study of the Pressure Profile Inside the NEG Coated Chambers of the SIS 18	vacuum, dipole, simulation, ion	2519
	M.C. Bellachioma, H. Kollmus, A. Krämer, J. Kurdal, H. Reich-Sprenger, L. Urban, M. Wengenroth GSI, Darmstadt, Germany
	In the context of the technical developments for the construction of FAIR at GSI, an intensive programme for the vacuum upgrade of the existing SIS 18 was started in 2005, with the aim to improve the beam lifetime and intensity. To reach these purposes also the installation of NEG coated dipole and quadrupole chambers is foreseen. During the upgrade shutdowns performed between 2006 and 2009 the vacuum chambers of approximately 65% of the SIS18 circumference were replaced by NEG coated pipes. To evaluate in detail the pressure profile inside the coated chambers mounted into the accelerator a dedicated experimental set-up, which reproduces a vacuum environment similar to the one of the SIS 18, was built. Using three gauges, mounted in different positions of a coated chamber, it was possible to measure the pressure in the range of 10^-12 mbar inside the activated NEG pipe and 10^-11 mbar outside the pipe at the pumping posts. Additionally, a modelling of a SIS18 vacuum sector was realised and the pressure variation values obtained by a Monte-Carlo simulation were compared with those measured. In this paper the experimental results and the vacuum simulations are described and discussed.

WEPPD077	Generation of Picosecond Electron-bunch Trains with Variable Spacing Using a Multi-pulse Photocathode Laser	laser, electron, wakefield, simulation	2705
	P. Piot Fermilab, Batavia, USA M.E. Conde, W. Gai, C.-J. Jing, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof ANL, Argonne, USA D. Mihalcea, P. Piot, M.M. Rihaoui Northern Illinois University, DeKalb, Illinois, USA
	Funding: Work supported by DOE awards FG-02-08ER41532 and DE-AC02-06CH11357. We demonstrate the generation of a train of electron bunches with variable spacing at the Argonne Wakefield Accelerator. The photocathode ultraviolet laser pulse consists of a train of four pulses produced via polarization splitting using two alpha-BBO crystals. The photoemitted electron bunches are then manipulated in a horizontally-bending dogleg with variable longitudinal dispersion. A downstream vertically-deflecting cavity is then used to diagnose the temporal profile of the electron beam. The generation of a train composed of four bunches with tunable spacing is demonstrated. Such train of bunch could have application to, e.g., the resonant excitation of wakefield in dielectric-lined waveguides.

WEPPP005	Progress on Muon Parametric-resonance Ionization Cooling Channel Development	resonance, emittance, simulation, betatron	2729
	V.S. Morozov, Y.S. Derbenev JLAB, Newport News, Virginia, USA A. Afanasev GWU, Washington, USA K.B. Beard, R.P. Johnson Muons, Inc, Batavia, USA B. Erdelyi, J.A. Maloney Northern Illinois University, DeKalb, Illinois, USA
	Funding: Supported in part by DOE SBIR grant DE-SC0005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Parametric-resonance Ionization Cooling (PIC) is intended as the final 6D cooling stage of a high-luminosity muon collider. To implement PIC, a continuous-field twin-helix magnetic channel was developed. A 6D cooling with stochastic effects off is demonstrated in a GEANT4/G4beamline model of a system where wedge-shaped Be absorbers are placed at the appropriate dispersion points in the twin-helix channel and are followed by short rf cavities. To proceed to cooling simulations with stochastics on, compensation of the beam aberrations from one absorber to another is required. Initial results on aberration compensation using a set of various-order continuous multipole fields are presented. As another avenue to mitigate the aberration effect, we optimize the cooling channel’s period length. We observe a parasitic parametric resonance naturally occurring in the channel’s horizontal plane due to the periodic beam energy modulation caused by the absorbers and rf. We discuss options for compensating this resonance and/or properly combining it with the induced half-integer parametric resonance needed for PIC. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

WEPPP015	Generation and Characterization of 5-micron Electron Beam for Probing Optical Scale Structures	electron, diagnostics, permanent-magnet, target	2753
	M.G. Fedurin, M. Babzien, V. Yakimenko BNL, Upton, Long Island, New York, USA B.A. Allen USC, Los Angeles, California, USA P. Muggli MPI, Muenchen, Germany A.Y. Murokh RadiaBeam, Santa Monica, USA
	In recent years advanced acceleration technologies have progress toward combination of electron beam, laser and optical scale dielectric structures. In present paper described generation of the electron beam probe with parameters satisfied to perform test of such optical structures.

WEPPP064	Design and Simulation of the Stripline Transverse Quadrupole Kicker for HLS II	kicker, impedance, dipole, storage-ring	2852
	F.F. Wu, W.B. Li, P. Lu, T.J. Ma, B.G. Sun, Y.Y. Xiao, H. Xu, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	In order to investigate the possibility of excite a transverse quadrupole mode oscillation of the electron bunch in the HLS II storage ring, we design a stripline transverse quadrupole kicker. The characteristic impedance of some modes(dipole modes, sum mode, quadrupole mode) of the optimised stripline kicker must match 50Ω characteristic impedance of the external transmission lines so as to reduce the reflected power. We use nonlinear least square method to optimise the kicker and compare characteristic impedances of calculation using 2D Possion code and fitted function of several variables, then we get optimised size with integrated use of Possion code and fitted function of several variables. Using the 2D Poisson code, we simulate the electric field distribution of dipole modes when the horizontal or the vertical electrodes are at opposite unit potentials, and the electric field distribution of quadrupole mode using quadrupole kick. We verified that the designed stripline kicker can excite a transverse quadrupole mode oscillation of the electron bunch.

WEPPP083	Near Real-time Response Matrix Calibration for 10-Hz GOFB	feedback, dipole, damping, injection	2903
	C. Liu, R.L. Hulsart, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty 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. The 10-Hz global orbit feedback, for damping the trajectory perturbation (~10 Hz) due to the vibrations of the triplets, is operational for injection and store in RHIC. The operation of the system has been performed using transfer functions between the beam position monitors and correctors obtained from the online optics model and a correction algorithm based on singular value decomposition (SVD). Calibration of the transfer functions by measuring the beam position oscillations while modulating the dedicated correctors has been carried out. The feedback results with model matrix and measured matrix will be compared.

WEPPP085	Study on the Realignment Plan for J-PARC 3 GeV RCS after the Tohoku Earthquake in Japan	injection, extraction, survey, alignment	2909
	N. Tani, H. Hotchi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	J-PARC 3GeV RCS suffered the big damage to its building and cooling and electric facilities by the Tohoku Region Pacific Coast Earthquake on March 11, 2011. After the earthquake, RCS magnets were measured to confirm the state of accelerator beam line. As a result, it was found out that there was an alignment error of several millimeters in both horizontal and vertical directions that caused a deformation in the J-PARC 3GeV RCS tunnel. In this paper, we report the survey result in the accelerator tunnel after the earthquake and the realignment plan for J-PARC 3GeV RCS.

WEPPP087	The Improvement and Test of Laser Positioning System for TPS Magnets Alignment Inspection	laser, alignment, sextupole, insertion	2915
	M.L. Chen, J.-R. Chen, H.C. Ho, K.H. Hsu, W.Y. Lai, C.-S. Lin, C.J. Lin, H.C. Lin, H.M. Luo, S.Y. Perng, P.L. Sung, Y.L. Tsai, T.C. Tseng, H.S. Wang, M.H. Wu NSRRC, Hsinchu, Taiwan
	A Laser positioning system, consist of a laser, laser position sensing devices (PSD) module and two granite blocks, is developed for the alignment inspection of TPS (Taiwan Photon Source) quadrupole and sextupole magnets during installation on a girder. The PSD module is adapted on the pole center of magnet and is designed to stand for mechanical center of magnets. For high accuracy, eliminating the influence of magnets manufacturing errors between PSD module is a major work. The PSD is mounted on a precise diameter expansible jig to absorb the manufacturing errors. The real roundness of the expansible jig can keep under 3um when diameter is expanded 80um. The PSD position is adjusted and corrected in advance, and then the PSD module center can be identical to the ideal pole position of magnets on the girder within 15um. The magnet will be aligned and adjusted by laser position on PSD. This paper describes how to eliminate the measuring error caused by magnet manufacturing error and the detail of alignment inspection procedure of magnets during the installation on a girder.

WEPPR004	Effect of Beam-beam Interactions on Stability of Coherent Oscillations in a Muon Collider	collider, luminosity, resonance, lattice	2940
	K. Ohmi KEK, Ibaraki, Japan Y. Alexahin Fermilab, Batavia, USA
	In order to achieve the peak luminosity of a muon collider in the 10³⁵ cm^-2 s^-1 range the number of muons per bunch should be of the order of a few units of 10¹² rendering the beam-beam parameter as high as 0.1 per IP. Such strong beam-beam interaction can be a source of instability if the working point is chosen close to a coherent beam-beam resonance. On the other hand, the beam-beam tune spread can provide a mechanism of suppression of the beam-wall driven instabilities. In this report the coherent instabilities driven by beam-beam and beam-wall interactions are studied with the help of BBSS code for the case of 1.5 TeV c.o.m muon collider.

WEPPR019	Catalogue of Losses for the IFMIF Prototype Accelerator	rfq, linac, SRF, solenoid	2982
	P.A.P. Nghiem, N. Chauvin, D. Uriot CEA/DSM/IRFU, France M. Comunian INFN/LNL, Legnaro (PD), Italy C. Oliver CIEMAT, Madrid, Spain
	For machine and personal protection purposes, precise knowledge of beam loss location and power are crucial, especially in a high intensity, high power accelerator like the IFMIF prototype. This paper aims at discussing the protocol of appropriate studies in order to give the catalogue of beam losses in different conditions: nominal, tuning and accidental. Then results of these studies are given.

WEPPR027	Complete Electromagnetic Design of the ESS-Bilbao RFQ Cold Model	rfq, dipole, simulation, radio-frequency	2991
	A. Vélez, I. Bustinduy, J. Feuchtwanger, N. Garmendia, O. González, I. Madariaga, J.L. Muñoz, D. de Cos ESS Bilbao, Bilbao, Spain F.J. Bermejo Bilbao, Faculty of Science and Technology, Bilbao, Spain V. Etxebarria, J. Portilla University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
	In this work, the ESS-Bilbao 352,2 Mhz RFQ Cold Model to be built in the ESS-Bilbao accelerator facility is presented. The Cold Model intends to be a small scale representation of the final 4 meters long RFQ which will be able to accelerate a 75 mA proton beam from 75 keV to 3 MeV. The work shown here covers the complete electromagnetic design process of the Cold Model which will be built in aluminium with a total length of 1 meter. Moreover, in order to find out fabrication tolerances, a longitudinal test modulation in the vane regions similar to the one designed for the final RFQ is included in the Cold Model. This modulation represents also a useful tool in order to test the agreement between measurements and electromagnetic simulations. In addition, a complete parametric study of the RFQ ends and radial matchers is presented as an important design parameter able to adjust the field flatness. Finally, slug tuning rods are also added to be able to test the tuning procedures. A final RFQ Cold Model prototype has been designed and is currently under fabrication.

WEPPR039	Nonlinear Lattice for Space-Charge Dominated Beam Transport with Suppressed Emittance Growth	focusing, space-charge, emittance, lattice	3021
	Y.K. Batygin, A. Scheinker LANL, Los Alamos, New Mexico, USA
	We present a feasible design for the implementation of a beam emittance growth suppressing lattice for space-charge dominated beams. Our analysis is based on original derivations developed in . We present a FODO focusing channel with quadrupole and duodecapole components which on average create the ﬁeld required to match the high-brightness beam with the structure. Matched beam exhibits smaller emittance growth than that in regular quadrupole focusing channel. Numerical results demonstrate the lattice’s performance in preventing halo formation of a nonuniform space charge dominated beam. Y. Batygin, Phys. Rev. E, 57, 5, p. 6020 (1998).

WEPPR040	Intensity Effects of the FACET Beam in the SLAC Linac	linac, emittance, wakefield, alignment	3024
	F.-J. Decker, N. Lipkowitz, J. Sheppard, 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 beam for FACET (Facility for Advanced aCcelerator Experimental Tests) at SLAC requires an energy-time correlation ("chirp") along the linac, so it can be compressed in two chicanes, one at the mid point in sector 10 and one W-shaped chicane just before the FACET experimental area. The induced correlation has the opposite sign to the typical used for BNS damping, and therefore any orbit variations away from the center kick the tail of the beam more than the head, causing a shear in the beam and emittance growth. Any dispersion created along the linac has similar effects due to the high (>1.2% rms) energy spread necessary for compression. The initial huge emittances could be reduced by a factor of 10, but were still bigger than expected by a factor of 2-3. Normalized emittance of 2 um-rad in Sector 2 blew up to 150 um-rad in Sector 11 but could be reduced to about 6-12 um-rad for the vertical plane although the results were not very stable. Investigating possible root causes for this, we found locations where up to 10 mm dispersion was created along the linac, which were finally verified with strong steering and up to 7 mm settling of the linac accelerator at these locations.

WEPPR047	The Effect of Non-Zero Closed Orbit on Electron-Cloud Pinch Dynamics	electron, proton, dipole, simulation	3033
	G. Franchetti GSI, Darmstadt, Germany F. Zimmermann CERN, Geneva, Switzerland
	A study on the pinch dynamics of electron cloud during a bunch passage under the effect of a single arbitrary-order multipole was presented at IPAC2011. The complexity of the pinch pattern is directly related to the order of the multipolar field. However, in a realistic situation, the proton beam will not be located in the center of the vacuum chamber. If the beam is offset a new pinch regime is encountered, where feed-down effects and asymmetry of pinch density render the dynamics more challenging. In this paper we discuss the pinch dynamics with orbit offset, including the resulting orbit variation along a bunch, and address their relevance for the incoherent effect of the electron cloud.

THYA01	High Field Magnet Developments	dipole, luminosity, alignment, collider	3185
	T. Nakamoto KEK, Ibaraki, Japan
	Superconducting magnets for future accelerators need to generate a field beyond 10 T. However, mature NbTi superconductors which have been already operated at its performance limit at LHC cannot be adopted. Instead, A15 type superconductors have been considered to be promising materials for the high field magnets. Especially, intensive R&D efforts for the LHC luminosity upgrade with state-of-the-art Nb3Sn superconductors have been carried out. Further future accelerators such as the High-Energy LHC and muon accelerators must require the high field reaching 20 T or more. This means that utilization of HTS (high Tc superconductors) would be the only possible solution. However, it is known that these advanced superconductors are not mechanically robust in comparison with the practical NbTi and the performance is influenced by mechanical stress and strain. In addition, magnetization effects caused by larger effective filament diameters may compromise the field quality in the accelerators. The magnet developments to overcome these issues are ongoing. This presentation will try to review the US and worldwide high field accelerator magnet developments: achievements, status, and plans.
	Slides THYA01 [7.578 MB]

THXB03	Beam and Spin Dynamics in an Electric Proton EDM Ring	proton, lattice, dipole, storage-ring	3203
	R.M. Talman CLASSE, Ithaca, New York, USA J. Talman BNL, Upton, Long Island, New York, USA
	Electric dipole moment (EDM) measurements may help to answer the question ‘‘Why is there more matter than anti-matter in the present universe?'' For a charged baryon like the proton such a measurement is thinkable only in a ring in which a bunch of protons is stored for more than a few minutes, with polarization ‘‘frozen'' (relative to the beam velocity) and with polarization not attenuated by decoherence. Beam and spin dynamics in an all-electric lattice with these characteristics is described. Rings for other charged baryons, such as deuterons or helium-3 nuclei, are also possible but, requiring both electric and magnetic fields, they are more complicated.
	Slides THXB03 [0.155 MB]

THPPC010	Beam Start-up of J-PARC Linac after the Tohoku Earthquake	linac, DTL, acceleration, radiation	3293
	M. Ikegami, Z. Fang, K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan T. Maruta, A. Miura, H. Sako, J. Tamura, G.H. Wei JAEA/J-PARC, Tokai-mura, Japan
	The beam operation of J-PARC linac was interrupted by the Tohoku earthquake in March 2011. After significant recovering effort including the realignment of most linac components, we have resumed the beam operation of J-PARC linac in December 2011. In this paper, we present the experience in the beam start-up tuning after the earthquake and the status of the linac operation thereafter.

THPPC034	Design and Analysis of the PXIE CW Radio-frequency Quadrupole (RFQ)	rfq, cavity, controls, vacuum	3359
	S.P. Virostek, M.D. Hoff, A.R. Lambert, D. Li, J.W. Staples LBNL, Berkeley, California, USA G.V. Romanov Fermilab, Batavia, USA C. Zhang IAP, Frankfurt am Main, Germany
	Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231. The Project X Injector Experiment (PXIE) will be a prototype front end of the Project X accelerator proposed by Fermilab. PXIE will consist of an H⁻ ion source, a low-energy beam transport (LEBT), a radio-frequency quadrupole (RFQ) accelerator, a medium-energy beam transport (MEBT) and a section of superconducting cryomodules that will accelerate the beam from 30 keV to 30 MeV. LBNL has developed an RFQ design for PXIE with fabrication scheduled to begin before the end of CY 2012. The chosen baseline design is a four-vane, 4.4 m long CW RFQ with a resonant frequency at 162.5 MHz (2.4 wavelengths long). The RFQ will provide bunching and acceleration of a nominal 5 mA H⁻ beam to 2.1 MeV. The relatively low wall power density results in wall power losses that are less than 100 kW. The beam dynamics design has been optimized to allow for more than 99% beam capture with exceptionally low longitudinal emittance. The RFQ mechanical design and the results of RF and thermal analyses are presented here.

Paper

Title

Other Keywords

Page

MOEPPB004

A Compact Ring Design with Tunable Momentum Compaction

damping, dynamic-aperture, dipole, emittance

82

Y. Sun
SLAC, Menlo Park, California, USA

A storage ring with tunable momentum compaction has the advantage in achieving diﬀerent RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and pre- damping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and ﬁne tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

MOEPPB008

Simulation of Hollow Electron Beam Collimation in the Fermilab Tevatron Collider

electron, simulation, collimation, collider

94

G. Stancari, I.A. Morozov, A. Valishev
Fermilab, Batavia, USA
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. This work was partially supported by the US LHC Accelerator Research Program (LARP).
The concept of augmenting the conventional collimation system of high-energy storage rings with a hollow electron beam was successfully demonstrated in experiments at the Tevatron. A reliable numerical model is required for understanding particle dynamics in the presence of a hollow beam collimator. Several models were developed to describe imperfections of the electron beam profile and alignment. The features of the imperfections are estimated from electron beam profile measurements. Numerical simulations of halo removal rates are compared with experimental data taken at the Tevatron.

MOPPC002

Local Chromatic Correction Scheme and Crab-waist Collisions for an Ultra-low β^* at the LHC

sextupole, optics, luminosity, resonance

118

J.L. Abelleira, S. Russenschuck, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
J.L. Abelleira
EPFL, Lausanne, Switzerland
C. Milardi, M. Zobov
INFN/LNF, Frascati (Roma), Italy
K. Ohmi
KEK, Ibaraki, Japan
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu- CARD, grant agreement no. 227579.
We discuss potential merits and the parameter range of interest for a possible crab-waist collision scheme at the LHC, and report preliminary optics studies of a local chromatic correction scheme with flat beams (β_x^*>>β_y^*), which could boost the LHC luminosity by about an order of magnitude and would also allow for crab-waist collisions.

MOPPC004

Experiments on the Margin of Beam Induced Quenches for LHC Superconducting Quadrupole Magnet in the LHC

injection, proton, kicker, monitoring

124

C. Bracco, W. Bartmann, M. Bednarek, B. Goddard, E.B. Holzer, A. Nordt, M. Sapinski, R. Schmidt, M. Solfaroli Camillocci, M. Zerlauth, E.N. del Busto
CERN, Geneva, Switzerland

Protection of LHC equipment relies on a complex system of collimators to capture injected or circulating beam in case of LHC injection kicker magnet failures. However, for specific failures of the injection kicker, the beam can graze the injection protection collimators and induce quenches of downstream superconducting magnets. This occurred twice during 2011 operation and can also not be excluded during further operation. Tests were performed during Machine Development periods of the LHC to assess the quench margin of the quadrupole located just downstream of the last injection protection collimator in point 8. In addition to the existing Quench Protection System, a special monitoring instrumentation was installed at this magnet to detect any resistance increase below the quench limit. The correlation between the magnet and Beam Loss Monitor signals was analysed for different beam intensities and magnet current. The results of the experiments are presented in this paper.

MOPPC006

90m Optics Studies and Operation in the LHC

optics, proton, injection, target

130

H. Burkhardt, G.J. Müller, S. Redaelli, R. Tomás, G. Vanbavinckhove, J. Wenninger
CERN, Geneva, Switzerland
S. Cavalier
LAL, Orsay, France

A high β^* = 90 m optics was commissioned and used for first very forward physics operation in the LHC in 2011. The experience gained from working with this optics in 5 studies and operation periods in 2011 was very positive. The target β^* = 90 m was reached by a de-squeeze from the standard 11 m injection and ramp optics on the first attempt and collisions and first physics results obtained in the second study. The optics was measured and corrected with good precision. The running conditions were very clean and allowed for measurements with roman pots very close to the beam.

MOPPC007

Plans for High Beta Optics in the LHC

optics, emittance, insertion, scattering

133

H. Burkhardt, A. Macpherson
CERN, Geneva, Switzerland
S. Cavalier, P.M. Puzo
LAL, Orsay, France

Based on what has been learned with the first high β^* = 90 m operation in 2011, we describe the potential and practical scenarios for reaching very high β^* in the LHC in 2012 and beyond. Very high β^* optics require dedicated running time and conditions in the LHC. We describe a plan which is optimized to maximize the physics potential in a minimum of dedicated running time.

MOPPC010

Parametric Study of Optics Options for the HL-LHC Project

optics, luminosity, insertion, sextupole

142

R. De Maria
CERN, Geneva, Switzerland

Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, cofunded by the DoE, USA and KEK, Japan.
The LHC Upgrade studies have been recently formalized into the High-Luminosity LHC (HL-LHC) project. The paper explores the parameter space in terms minimum beta star (flat and round), and luminosity leveling scenarios, constrained by the triplet gradient and aperture and still compatible with optics solutions based on the ATS scheme*. The limitations of the proposed solutions, essentially given by the preservation of the dynamic aperture in the presence of large beta-beating waves induced in the arcs by the squeezing scheme are investigated. The results will be combined in scaling laws benchmarked with existing fully developed scenarios.
* S. Fartoukh et al., "The Achromatic Telescopic Squeezing (ATS) scheme: from initial motivations to basic principles, and first demonstration at the LHC," these proceedings.

MOPPC011

Optics and Layout Solutions for the HL-LHC with Large Aperture Nb3Sn and Nb-Ti Inner Triplets

optics, dynamic-aperture, insertion, injection

145

S.D. Fartoukh, R. De Maria
CERN, Geneva, Switzerland

Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, co-funded by the DoE, USA and KEK, Japan.
The LHC Upgrade studies, formalized into the High-Luminosity LHC (HL-LHC) project, relies on the feasibility of very low β^*, and in particular on a novel achromatic squeezing mechanism, the ATS scheme which is presently under test in the LHC*. We present two optics and layout scenario for the HL-LHC using the ATS scheme, one based on Nb3Sn triplet quadrupoles with a coil aperture compatible with an operational gradient of 150T/m and a backup scenario based on NbTi compatible with an operational gradient of 100T/m. The solution obtained are analyzed in terms of β^* reach (flat or round), mechanical acceptance, optics flexibility, chromatic properties, and impact on the dynamic aperture due to the large beta-beating waves induced in the arcs by the ATS scheme.
* S. Fartoukh et al., "The Achromatic Telescopic Squeezing (ATS) scheme: from initial motivations to basic principles, and first demonstration at the LHC," these proceedings.

MOPPC016

Combined Ramp and Squeeze at the Large Hadron Collider

optics, injection, collider, dipole

157

S. Redaelli, M. Lamont, G.J. Müller, R. Tomás, J. Wenninger
CERN, Geneva, Switzerland
N. Ryckx
EPFL, Lausanne, Switzerland

In the first two years of operation of the CERN Large Hadron Collider (LHC), the betatron squeeze has been carried out at constant flat top energy of 3.5 TeV. Squeeze setting functions are separated from the energy ramp functions. This ensured a maximum flexibility during commissioning because stopping at all intermediate optics for detailed measurements was possible. In order to then improve the efficiency of the operational cycle, combining the ramp and squeeze has been considered. In this paper, the various possibilities for this scheme are reviewed, and proposals of optimized operational cycles with combined ramp and squeeze are presented for different energies. Results of beam tests are also discussed.

MOPPC020

Field Tolerances for the Triplet Quadrupoles of the LHC High Luminosity Lattice

multipole, dynamic-aperture, target, lattice

169

Y. Jiao, Y. Cai, Y. Nosochkov, M.-H. Wang
SLAC, Menlo Park, California, USA
R. De Maria, S.D. Fartoukh, M. Giovannozzi, E. McIntosh
CERN, Geneva, Switzerland

Funding: This work is supported by the U.S. Department of Energy under contract # DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
It has been proposed to implement an Achromatic Telescopic Squeezing (ATS) scheme* in the high luminosity LHC lattice to reduce the beta functions at the Interaction Points (IP) up to a factor of 8. As a consequence, the nominal 4.5-km peak beta functions reached in the inner triplets at collision will be increased by the same factor. This therefore justifies the installation of new, larger aperture superconducting triplet quadrupoles. These higher beta functions will enhance the effects of the triplet quadrupole field errors leading to smaller beam dynamic aperture. To maintain the acceptable dynamic aperture, the effects of the triplet multipole field errors must be re-evaluated, thus specifying new tolerances. Such a study has been performed for the so-called “4444” collision optics of the ATS scheme, where the IP beta functions are reduced by a factor of 4 in both planes with respect to a pre-squeezed value of 60 cm at two collision points. The dynamic aperture calculations were performed using SixTrack. The impact on the triplets’ field quality is studied and presented in details.
* S. Fartoukh, “An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade”, Proc. of IPAC11, p. 2088 (2011).

MOPPC029

Off-momentum Beat-beat Correction in the RHIC Proton Run

sextupole, simulation, proton, lattice

196

Y. Luo, M. Bai, W. Fischer, A. Marusic, K. Mernick, S.M. White
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.
In this article we will present the measurement and correction of the off-momentum β^*-beat in the RHIC proton run. The beta-beat will be measured with the AC dipole and by shifting RF frequency. We will focus on the correction of the off-momentum beta-beat at the interaction points IP6 and IP8 with the arc chromatic sextupole families. The effects of the off-momentum beta-beat correction on the global chromaticities and dynamic aperture will be estimated through beam experiments and the numerical simulation.

MOPPC045

Scaled Electron Model of a Dogbone Muon RLA with Multi-pass Arcs

linac, electron, dipole, optics

235

S.A. Bogacz, A. Hutton, G.A. Krafft, V.S. Morozov, Y. Roblin
JLAB, Newport News, Virginia, USA
K.B. Beard, R.P. Johnson
Muons, Inc, Batavia, 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 for a future Neutrino Factory and 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 single pass 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 an area of 25 by 7 m. The scheme utilizes only fixed magnetic fields including injection and extraction. The hardware requirements are not very demanding, making it feasible to utilize the existing technologies.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

MOPPC057

Some Comments to Magnetic Field Representation for Beam Dynamic Calculations

multipole, dipole, vacuum, resonance

262

P. Schnizer, E.S. Fischer
GSI, Darmstadt, Germany
A. Mierau
TEMF, TU Darmstadt, Darmstadt, Germany
B. Schnizer
TUG/ITP, Graz, Austria

Machines with high currents and small apertures, as used for SIS100 of the FAIR project, require a sincere understanding of the resonances excited by the magnetic field distortions; typically performed by tracking codes. These codes model the field errors using a Taylor Series approximation of the field quality at the track of the ideal particle. The path of the particle within the elliptic aperture of the dipole is curved; thus the standard approach of using plane circular multipoles fails to model the real symmetry of the magnetic field, an important feature of effective field description for beam loss calculations. Therefore toroidal elliptic multipoles were developed which allow describing the magnetic field concisely in an elliptic vacuum chamber in curved dipoles and quadrupoles. In this talk we present the appropriate description and its limitation, illustrate their usefullness based on the static and transient magnetic field measurements of the first curved SIS100 dipole next to the SIS18 dipole.

MOPPC074

Evolution of MAD-X in the Framework of LHC Upgrade Studies

multipole, simulation, optics, luminosity

304

A. Latina, L. Deniau
CERN, Geneva, Switzerland

The design efforts for the High Luminosity upgrade of the Large Hadron Collider (HL-LHC) will require significant extensions of the MAD-X code widely used for designing and simulating particles accelerators. For this purpose, several new capabilities have been added to the code, namely the possibility to simulate crab cavities for crossing angle compensation, with their imperfections; the selective introduction of thick quadrupole elements for particles tracking, improving the previous implementation entirely based on thin-lenses; and the upgrade of the interface to SixTrack used for distributed tracking with, e.g., LHC@home. These changes are framed into a global redesign of the MAD-X architecture meant to consolidate its structure, improve its performances, and increase its flexibility. Such improvements are described in details in the present paper.

MOPPC079

Modelling of the EMMA ns-FFAG Ring Using GPT

space-charge, emittance, injection, electron

319

R.T.P. D'Arcy, S. Jolly
UCL, London, United Kingdom
J.K. Jones, B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

EMMA (Electron Machine with Many Applications) is a prototype non-scaling Fixed-Field Alternating Gradient (ns-FFAG) accelerator whose construction at Daresbury Laboratory, UK, was completed in the autumn of 2010. The energy recovery linac ALICE will serve as an injector for EMMA, within an energy range of 10 to 20 MeV. The injection line consists of a symmetric 30 degree dogleg to extract the beam from ALICE, a matching section and a tomography section for transverse emittance measurements. This is followed by a transport section to the injection point of the EMMA ring. The ring is composed of 42 cells, each containing one focusing and one defocusing quadrupole. Acceleration over many turns of the EMMA machine has recently been confirmed. In some cases the bunch will traverse upwards of 100 turns, at which point the effects of space-charge may be significant. It is therefore necessary to model the electron beam transport in the ring using a code capable of both calculating the effect of and compensating for space-charge. Therefore the General Particle Tracer (GPT) code has been used. A range of injection beam parameters have been modeled for comparison with experimental results.

MOPPC082

Beam Dynamics Simulations inProject X RFQ with CST Studio Suite

rfq, simulation, acceleration, linac

328

G.V. Romanov
Fermilab, Batavia, USA

Typically the RFQs are designed using the Parmteq, DesRFQ and other similar specialized codes, which produces the files containing the field and geometrical parameters for every cell. The beam dynamic simulations with these analytical fields are, of course, ideal realizations of the designed RFQs. The new advanced computing capabilities made it possible to simulate beam and even dark current in the realistic 3D electromagnetic fields in the RFQs that may reflect cavity tuning, presence of tuners and couplers, RFQ segmentation etc. The paper describes the utilization of full 3D field distribution obtained with CST Studio Suite for beam dynamic simulations using both PIC solver of CST Particle Studio and the beam dynamic code TRACK.

MOPPC083

LinguaFranca - A Graphical User Interface for Accelerator Modeling

simulation, lattice, optics, collider

331

T.J. Roberts
Muons, Inc, Batavia, USA

This is a proposed project to develop an innovative Graphical User Interface that permits users to construct, explore, optimize, and evaluate accelerator systems efficiently and effectively. While it will be designed with students in mind, accelerator physicists will also find it useful in dealing with the plethora of modeling tools and their different languages. The internal representation of the system is specifically designed to be useable as a text-based description of the system, and to make it easy for users to interface it to essentially any accelerator-modeling tool, regardless of its description language. Many accelerator designers have expressed frustration with the current “Tower of Babel” among modeling programs, and this project will address that directly. In particular, this will make it straightforward to use fast but less realistic programs to design and optimize a system, and then use slower but more realistic programs to evaluate its performance. Graphical interfaces are emphasized, making it easy to construct the system graphically, display the system and its beam, and use on-screen controls to vary parameters and observe their effects immediately.

MOPPD041

Beam Loss Protection for a 2.3 Megawatt LBNE Proton Beam

dipole, proton, power-supply, target

454

R.M. Zwaska, S.C. Childress, A.I. Drozhdin, N.V. Mokhov, I.S. Tropin
Fermilab, Batavia, USA

Funding: U.S. Department of Energy.
Severe limits are required for allowable beam loss during extraction and transport of a 2.3 MW primary proton beam for the Long Baseline Neutrino Experiment (LBNE) at Fermilab. Detailed simulations with the STRUCT and MARS codes have evaluated the impact of beam loss of 1.6·10¹⁴ protons per pulse at 120 GeV, ranging from a single pulse full loss to sustained small fractional loss. It is shown that localized loss of a single beam pulse at 2.3 MW will result in a destructive event: beam pipe failure, damaged magnets and high levels of residual radiation inside the tunnel. A sustained full beam loss would be catastrophic. Acceptable beam loss limits have been determined and robust solutions developed to enable efficient proton beam operation under these constraints.

MOPPD049

The Layout of the High Energy Beam Transport for the European Spallation Source

target, octupole, linac, beam-transport

475

A.I.S. Holm, S.P. Møller, H.D. Thomsen
ISA, Aarhus, Denmark

The status of the High Energy Beam Transport (HEBT) line for the European Spallation Source (ESS) is presented. The HEBT brings the beam from the underground linac to the target at surface level. The main design objectives of the HEBT, such as space for upgrades, producing the desired target footprint etc. are discussed and the preferred design is shown. Large amplitude particles, a halo, are formed in the last part of the linac. Hence, every given value of the peak current density at the target is correlated with a certain power deposited outside the beam footprint. This correlation is studied and optimized. Furthermore, first studies of the vertical stability of the beam footprint and profile on target due to misalignment or mismatch of the incoming beam are made.

MOPPD051

Performance of Resonant Slow Extraction from J-PARC Main Ring

extraction, feedback, proton, septum

481

M. Tomizawa, Y. Arakaki, T. Kimura, S. Murasugi, R. Muto, H. Nakagawa, K. Okamura, H. Sato, Y. Shirakabe, T. Toyama, E. Yanaoka, M. Yoshii
KEK, Ibaraki, Japan
D. Horikawa
Sokendai, Ibaraki, Japan
K. Mochiki
Tokyo City University, Tokyo, Japan
A. Schnase
JAEA/J-PARC, Tokai-mura, Japan

Proton beam accelerated by the J-PARC main ring (MR) with an imaginary transition lattice is slowly extracted by a third integer resonant extraction scheme and delivered to the hadron experimental hall. One of the critical issues in the slow extraction from a high intensity proton synchrotron is the inevitable beam loss caused by the extraction process at septum devices. A design with low beam loss (high extraction efficiency) is required to reduce machine damage and radiation exposure during hands-on maintenance. We have designed the slow extraction scheme to obtain high extraction efficiency for the MR lattice. The scheme has a large step size and a small angular spread enabling a hit rate of the beam on the developed thin septum device. Since the first 30 GeV proton beam was successfully delivered to the experimental hall in January 2009, an extremely high extraction efficiency of 99.5% has been achieved by an intensive beam tuning. In this paper, we report details of such performance. We will also describe some schemes to improve the serious spiky spill time structure due to large current ripples from the power supplies for the bending and quadrupole magnets.

MOPPD057

CERN PSB-to-PS Transfer Modifications for the 2 GeV Upgrade

injection, optics, dipole, septum

493

W. Bartmann, J. Borburgh, S.S. Gilardoni, B. Goddard, A. Newborough, S. Pittet, R. Steerenberg
CERN, Geneva, Switzerland
C.H. Yu
IHEP, Beijing, People's Republic of China

Within the frame of the CERN PS Booster (PSB) energy upgrade from 1.4 to 2 GeV, the PSB to PS transfer line will be adapted for pulse-to-pulse modulated operation. A modified lattice is presented including a re-design of the switching dipole between ISOLDE and PS and additional collimators to protect the PS injection septum. Optics solutions optimized for small emittance LHC beams as well as for the large emittance high-intensity beams are shown.

MOPPD060

Modified Extraction Scheme for the CERN PS Multi-Turn Extraction

extraction, septum, kicker, beam-losses

502

M. Giovannozzi, S.S. Gilardoni, C. Hernalsteens, A. Lachaize, G. Métral
CERN, Geneva, Switzerland

High-activation of the extraction magnetic septum of the CERN PS machine was observed due to the losses of the continuous beam extracted via the Multi-Turn Extraction (MTE) method. A possible mitigation measure consists of using an existing electrostatic septum, located upstream of the extraction magnetic septum, to deflect the beam. This would highly decrease the beam losses, and hence the induced activation, during the rise time of the MTE kickers due to the reduced thickness of the electrostatic septum with respect to the magnetic one. The layout of this new extraction will be described in detail and the results of beam measurements presented.

MOPPP015

Status of the BERLinPro Energy Recovery Linac Project

cavity, linac, SRF, booster

601

J. Knobloch, M. Abo-Bakr, W. Anders, R. Barday, K.B. Bürkmann-Gehrlein, V. Dürr, S.C. Heßler, A. Jankowiak, T. Kamps, O. Kugeler, B.C. Kuske, P. Kuske, A.N. Matveenko, G. Meyer, R. Müller, A. Neumann, K. Ott, Y. Petenev, D. Pflückhahn, T. Quast, J. Rahn, S.G. Schubert
HZB, Berlin, Germany

Funding: Funding provided by the BMBF and the State of Berlin
In October 2010 Helmholtz Zentrum Berlin received funding to design and build the Berlin Energy Recovery Linac Project BERLinPro. The goal of this compact ERL is to develop the accelerator physics and technology required to generate and accelerate a 100-mA, 1 mm·mrad emittance beam. Given the flexibility of ERLs, other operation modes such as short-bunch operation will also be investigated. The BERLinPro technology and know-how can then be transferred to a variety of ERL-based applications. Presently, BERLinPro is in the design phase and the optics has been settled. Furthermore, first beam has been achieved with a superconducting RF photoinjector, which represents an important step towards realizing a CW injector for BERLinPro. An overview of the present status and the conceptual design report is presented.

MOPPP038

Optics Design and Layout for the Electron Beam Test Facility at Daresbury Laboratory

gun, beam-transport, laser, emittance

646

D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.K. Jones
Cockcroft Institute, Warrington, Cheshire, United Kingdom

An Electron Beam Test Facility (EBTF) is being developed at Daresbury Laboratory to provide the beam for industrial applications and as a front end of future light source facility test under consideration. The RF photoinjector will deliver ~6 MeV beam to industrial users* and will serve as an injector for the future light source facility under consideration at Daresbury**. The Photoinjector design in first phase consists of 2.5 cell RF gun (on loan from Strathclyde) to be driven by Ti:S laser. The photo injector design is aimed to deliver bunches with 10-250 pC bunch charge at low transverse emittances and short bunch lengths. The beam transport optics design described in this paper includes a dedicated diagnostics section capable of measuring ultra short and ultra low emittance bunches and transport to two user areas.
* P. McIntosh, these proceedings.
** J. Clarke, these proceedings.

MOPPR010

Simultaneous Measurement of Emittance at the Storage Ring and the External Beamlines of ELSA

emittance, synchrotron, extraction, diagnostics

792

S. Zander, F. Frommberger, W. Hillert, D. Proft
ELSA, Bonn, Germany

Funding: Funded by the DFG within the SFB / TR 16.
The Electron Stretcher Facility (ELSA) consists of several accelerator stages, the last one being a storage ring providing a beam of polarized electrons of up to 3.5 GeV. To ensure a high duty cycle, a slow extraction via a third integer resonance is applied at ELSA. The resonance extraction cause a variation of the emittance in the external beamline. A system for simultaneous measurement of emittance in the storage ring and the external beamlines has been installed. First results including a comparison of both emittances will be shown.

MOPPR023

Stripline BPM with Integral In-Vacuo Termination

impedance, pick-up, vacuum, coupling

828

A. Stella, A. Ghigo, V.L. Lollo, F. Marcellini, M. Serio
INFN/LNF, Frascati (Roma), Italy

We report the design and realization of a stripline type beam position monitor to be used in the SPARC LAB transfer lines. While the directional properties provided by matched termination at the downstream end are not strictly required in a transfer line, yet matched loads at the end of the stripline electrodes are preferable to reduce the loss factor and to avoid unwanted reflection to the detection electronic. The Integration of a matched resistive load inside the vacuum chamber allows to halve the number of UHV feedthroughs.

MOPPR024

Non-intercepting Emittance Measurements by means of Optical Diffraction Radiation Interference for High Brightness Electron Beam

radiation, electron, emittance, target

831

A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
V. Balandin, N. Golubeva, K. Honkavaara, G. Kube
DESY, Hamburg, Germany
M. Castellano, E. Chiadroni
INFN/LNF, Frascati (Roma), Italy
L. Catani
INFN-Roma II, Roma, Italy

Conventional intercepting transverse electron beam diagnostics, e.g. based on Optical Transition Radiation (OTR), cannot tolerate high power beams without remarkable mechanical damages of the diagnostics device. Optical Diffraction Radiation (ODR) is an excellent candidate for the measurements of the transverse phase space parameters in a non-intercepting way. One of the main limitations of this method is the low signal to noise ratio, mainly due to the unavoidable synchrotron radiation background. This problem can be overcome by using ODRI (Optical Diffraction Radiation Interference). In this case the beam goes through two slits opened on metallic foils, placed in a distance shorter than the radiation formation zone. Thanks to the shielding effect of the first screen a nearly background-free ODR interference pattern can be measured allowing the determination of the beam size and the angular divergence. Here we report the first measurements, carried out at FLASH (DESY, Germany), of the beam emittance using ODRI. Our results demonstrate the unique potential of this technique.

MOPPR039

Development of Beam Position Monitor for PEFP Linac and Beam line

linac, proton, coupling, DTL

864

J.Y. Ryu, Y.-S. Cho, J.-H. Jang, H.S. Kim, H.-J. Kwon, K.T. Seol
KAERI, Daejon, Republic of Korea

Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government.
The development of the Beam Position Monitor (BPM) is in progress for the linac and beam lines of the Proton Engineering Frontier Project (PEFP). We choose a strip line BPM for the PEFP 20-MeV and 100-MeV beam lines in order to increase the sensitivity of the relatively long bunches in the beam lines. We also selected the same type BPM for the proton linac in the energy range between 20-MeV and 100-MeV. The prototype BPM was designed, fabricated and tested at KAERI site, where the 20-MeV linac was operated. To check the performance of the BPM, we performed the field mapping. The characteristics and test results of the BPM on the test bench as well as with 20-MeV proton beam will be presented in this paper.

MOPPR042

Characterization Tests of a Stripline Beam Position Monitor for the CLIC Drive Beam

impedance, extraction, simulation, feedback

873

A. Benot-Morell, A. Faus-Golfe, J.J. García-Garrigós
IFIC, Valencia, Spain
A. Benot-Morell, L. Søby
CERN, Geneva, Switzerland
J.M. Nappa, J. Tassan-Viol, S. Vilalte
IN2P3-LAPP, Annecy-le-Vieux, France
S.R. Smith
SLAC, Menlo Park, California, USA

Funding: FPA2010-21456-C02-01, SEIC-2010-00028
A prototype of a stripline Beam Position Monitor (BPM) with its associated readout electronics has been developed at CERN in collaboration with SLAC, LAPP and IFIC. In this paper, the design and simulations of the BPM with the analog readout chain and the BPM test bench are described, and the results of the first characterization tests are presented. The position resolution and accuracy parameters are expected to be below 2μm and 20μm respectively for a beam with a bunching frequency of 12GHz, an average current of 101A and a machine repetition rate of 50Hz.

MOPPR044

Optics and Emittance Studies using the ATF2 Multi-OTR System

coupling, emittance, target, controls

879

J. Alabau-Gonzalvo, C. Blanch Gutierrez, A. Faus-Golfe, J.J. García-Garrigós, J. Resta-López
IFIC, Valencia, Spain
J. Cruz, D.J. McCormick, G.R. White, M. Woodley
SLAC, Menlo Park, California, USA

Funding: Funding Agency: FPA2010-21456-C02-01. Work supported in part by Department of Energy Contract DE-AC02-76SF00515.
A multi-OTR system (4 beam ellipse diagnostic devices based on optical transition radiation) was installed in the extraction line of ATF2 and has been fully operational since September 2011. The OTRs have been upgraded with a motorized zoom-control lens system to improve beam finding and accommodate different beam sizes. The system is being used routinely for beam size and emittance measurements as well as coupling correction. In this paper we present measurements performed during the winter run of 2011 and the early 2012 runs. We show the reconstruction of twiss parameters and emittance, discuss the reliability of the OTR system and show comparisons with simulations. We also present new work to calculate all 4 coupling terms and form the “4-D” intrinsic emittance of the beam utilizing all the information available from the 2-D beam profile images. We also show details and experimental results for performing a 1-shot automated coupling correction.

MOPPR059

Modeling Space-charge and its Influence on the Measurement of Phase Space in ALICE by Tomographic Methods

space-charge, injection, electron, diagnostics

918

M.G. Ibison, D.J. Holder
The University of Liverpool, Liverpool, United Kingdom
K.M. Hock, B.D. Muratori, A. Wolski
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: STFC.
ALICE is an experimental electron accelerator designed to operate over a range of energies up to 35 MeV, and with up to 80 pC bunch charge. A dedicated tomography diagnostic section allows measurement of the transverse phase space with different beam parameters. In the low-energy, high-charge regime, space charge effects must be considered: to quantify these effects, the tracking code GPT has been used to simulate beams in the tomography diagnostic section. The results can be compared with simplified models, and with experimental measurements.

MOPPR060

Calibration of the EMMA Beam Position Monitors: Position, Charge and Accuracy

pick-up, injection, simulation, diagnostics

921

I.W. Kirkman
The University of Liverpool, Liverpool, United Kingdom
J.S. Berg
BNL, Upton, Long Island, New York, USA
G. Cox
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
A. Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The accurate determination of transverse beam position is essential to understanding the performance of an accelerator system, and this is particularly the case with non-scaling FFAG machines such as EMMA, where, due to fundamental principles of design, the beam may deviate widely from the central beampipe axis. This paper describes the various modelling approaches taken for the three different button pickup assemblies used in EMMA, and the subsequent methods of calibration (‘mappings’) which allow beam position and charge to be deduced from the processed BPM signals. The use and validity of the modelling and mapping approach adopted is described, and the contributions to positional and bunch charge uncertainty arising from these procedures is discussed.

MOPPR061

Computing Bunch Charge, Position, and BPM Resolution in Turn-by-Turn EMMA BPMs

pick-up, EPICS, injection, controls

924

A. Kalinin, J.K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R.G. Borrell
WareWorks Ltd, Manchester, United Kingdom
G. Cox
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
I.W. Kirkman
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The NS-FFAG electron model ‘EMMA’ and its Injection and Extraction Lines are equipped with a total of 53 EPICS VME BPMs*. In the BPMs, each opposite button signal pair is time-domain-multiplexed into one channel as a pulse doublet. The recording of turn-by-turn data into the BPM memory is triggered by the bunch itself on each of its passages. For each accelerating cycle, the BPMs deliver a snapshot of a turn-by-turn trajectory measured in each of 42 cells. Additional BPMs (two pairs) are used to obtain a Poincare map. We describe the EPICS architecture, and a set of Python data processing algorithms that are used to automatically set a BPM intensity range, to eliminate an error due to tails of the doublet pulses, to calculate the bunch charge and position, and, for a set of injections, to find the BPM resolution. We use three types of button pickup mappings** that allow: to eliminate bunch charge signal dependence on offset, to get a linear offset response, and to eliminate ‘quadrupole’ signal dependence on offset as well (which is used in resolution calculation). We present beam measurement results collected in 2011 runs.
* A. Kalinin et al., Proc. of IPAC’10, MOPE068, p. 1134, (2010.
** I. Kirkman, these proceedings.

MOPPR063

Exploiting the Undesired: Beam-gas Interactions in the LHC

vacuum, radiation, simulation, proton

927

R. Versaci, V. Baglin, M. Brugger
CERN, Geneva, Switzerland
A. Mereghetti
UMAN, Manchester, United Kingdom

The vacuum inside the LHC pipes has a key role in correct operation of the accelerator. The interaction of the beam with residual gas in the pipes can lead to the loss of the beam itself and damage accelerator components. Nevertheless, beam-gas interactions can be exploited to indirectly measure the gas pressure inside the beam pipe, detecting the secondaries produced. The showers generated are detected by Beam Loss Monitors, whose signals depend on the gas pressure. This technique would also allow to punctually measure the gas pressure in sections of the accelerator where vacuum gauges are not frequent, such as the arcs. The problem has been addressed by means of FLUKA simulations and the results have been benchmarked with direct measurements performed in the LHC in 2011.

MOPPR087

Transverse Beam Emittance Measurements of a 16 MeV Linac at the Idaho Accelerator Center

electron, emittance, linac, background

990

S. Setiniyaz, T.A. Forest
ISU, Pocatello, Idaho, USA
K. Chouffani, Y. Kim
IAC, Pocatello, IDAHO, USA
A. Freyberger
JLAB, Newport News, Virginia, USA

A beam emittance measurement of the 16 MeV S-band High Repetition Rate Linac (HRRL) was performed at Idaho State University's Idaho Accelerator Center (IAC). The HRRL linac structure was upgraded beyond the capabilities of a typical medical linac so it can achieve a repetition rate of 1 kHz. Measurements of the HRRL transverse beam emittance are underway that will be used to optimize the production of positrons using HRRL's intense electron beam on a tungsten converter. In this paper, we describe a beam imaging system using on an OTR screen and a digital CCD camera, a MATLAB tool to extract beamsize and emittance, detailed measurement procedures, and the measured transverse emittances for an arbitrary beam energy of 15 MeV.

MOPPR092

SVD-BASED METHOD FOR MEASUREMENT OF BEAM PARAMETERS AND FLAG RESOLUTION

emittance, simulation, booster, focusing

999

G.M. Wang, R.P. Fliller, I. Pinayev, T.V. Shaftan
BNL, Upton, Long Island, New York, USA

In NSLS II booster to storage ring transport line, the typical beam size in vertical plane is ~60 μm, which requires very high flag resolution to get good beam parameters measurement. This paper describes a new SVD-based method to measure transverse beam parameters and flag resolution simultaneously with double quads scan. Implementation simulations of the proposed method are performed for a dispersion free region in the NSLS-II booster to storage ring transport line. With this method, it breaks the limitation of beam parameters measurement accuracy duo to the flag resolution.

TUXA03

Increasing the AGS Beam Polarization with 80 Tune Jumps

resonance, polarization, emittance, closed-orbit

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]

TUOAA03

Tests of Low Emittance Tuning Techniques at SLS and DAΦNE

emittance, coupling, alignment, collider

1065

S.M. Liuzzo, M.E. Biagini, P. Raimondi
INFN/LNF, Frascati (Roma), Italy
M. Aiba
Paul Scherrer Institut, Villigen, Switzerland
M. Böge
PSI, Villigen, Switzerland

The SuperB collider design is based on extremely low emittances, comparable to those of synchrotron light sources. A Low Emittance Tuning (LET) algorithm was developed for SuperB and has been tested last year at DIAMOND. This paper will report on the results of the application of LET to SLS (PSI) and DAΦNE (LNF) in order to compare and confirm the previous results. In this tests, the correction of orbit, dispersion and coupling is applied simultaneously to the detection of Beam Position Monitors tilts. The effect of beam based alignment at DAΦNE is also presented, together with an evaluation of the effects of other possible sources of emittance growth.

Slides TUOAA03 [4.313 MB]

TUOBA03

H⁻ and Proton Beam Loss Comparison at SNS Superconducting Linac

proton, linac, ion, DTL

1074

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

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
A comparison of beam loss in the superconducting part (SCL) of the Spallation Neutron Source (SNS) linac for H⁻ and protons is presented. During the experiment the nominal beam of negative hydrogen ions in the SCL was replaced by a proton beam created by insertion of a thin stripping carbon foil placed in the low energy section of the linac. The observed significant reduction in the beam loss for protons is explained by a domination of the intra-beam stripping mechanism of the beam loss for H-. The details of the experiment are discussed, and a preliminary estimation of the cross section of the reaction H⁻ + H⁻ -> H⁻ + H⁰ + e is presented.

Slides TUOBA03 [0.772 MB]

TUPPC001

Quadrupole Shapes

optics, TRIUMF, controls, multipole

1149

R.A. Baartman
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

Traditionally, quadrupoles are shaped to have a constant vertical cross-section. In other words, the poles are cylindrical segments extended in the beam direction and circular or hyperbolic in cross section. At the ends, the poles are simply truncated or sometimes slightly smoothed with a chamfer. Even very short quadrupoles are often this shape. A new shape is derived analytically, and it is demonstrated that this shape yields dramatically smaller aberrations.

TUPPC003

Analytical Methods for Statistical Analysis for the Correction of Coupling Due to Errors

coupling, emittance, sextupole, betatron

1152

A. Chancé, J. Payet
CEA/DSM/IRFU, France
B. Dalena
CEA/IRFU, Gif-sur-Yvette, France

The statistical evaluation of the coupling induced by magnets errors and misalignments on the optics design of a machine are done by tracking and Monte Carlo methods. These techniques are CPU demanding and time consuming. During the preliminary optics design phase a faster technique can be useful to evaluate the order of magnitude and the effectiveness of the correction system. Analytical expression for the transport along the machine of the magnets errors and misalignment are derived at first order. A perturbative approach is used to take into account the effect of a non zero central trajectory in the multipoles. The coupling correction is obtained by minimizing the cross-talk central trajectory matrix response.

TUPPC018

Estimation of Orbit and Optics Distortion of SuperKEKB by Tunnel Deformation

emittance, optics, coupling, luminosity

1197

A. Morita, H. Koiso, Y. Ohnishi, K. Oide, H. Sugimoto
KEK, Ibaraki, Japan

The tunnel which was used for the KEKB B-factory is reused for the accelerator tunnel of the SuperKEKB. The total vertical displacement of the tunnel subsidence reached almost 30mm during 10 years KEKB operation. In order to operate the SuperKEKB which might be more delicate machine than the previous KEKB B-factory, we are evaluating the optics distortion by the tunnel deformation and studying the machine performance after the orbit and optics correction. We report the estimation of the machine performance degradation by the tunnel subsidence and the requirement of the correction.

TUPPC023

Waist Corrections at the Interaction Point of ATF2 in the Presence of IPBSM Fringe Rotations and Input Beam Sigma13, Sigma24

sextupole, coupling, simulation, alignment

1212

S. Bai, J. Gao
IHEP, Beijing, People's Republic of China
P. Bambade
LAL, Orsay, France

The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. In beam tuning towards the goal beam size, the presence of a tilt of the IP Shintake monitor fringe pattern with respect to the x-y coordinate system of the beam (or equivalently a σ13 correlation), as well as a σ24 correlation, can break the orthogonality in the main σ34 and σ32 waist corrections during the minimization and result in larger vertical beam sizes at IP. Both effects are studied, analytically and in simulation, and a practical procedure is suggested for diagnosing the presence of a residual fringe tilt, by measuring the influence of the horizontal waist correction on the minimum vertical beam size.

TUPPC027

Multi Objective Genetic Optimization for Linac Lattice of PAL XFEL

linac, lattice, electron, emittance

1224

C.H. Yi, M.-H. Cho, S.H. Kim, W. Namkung
POSTECH, Pohang, Kyungbuk, Republic of Korea
H.-S. Kang
PAL, Pohang, Kyungbuk, Republic of Korea
K.-J. Kim
ANL, Argonne, USA

Funding: Work supported by MEST and POSTECH Physics BK21 Program.
There are a large number of variables and objectives in design of XFEL linac lattices. Recently, most of accelerator physics field, are applying the multi-objective genetic algorithm (MOGA) for these kinds of problems. MOGA was applied to the PAL XFEL linac lattice design. Longitudinal position of all components was fixed before applying MOGA. RF parameters of RF cavities and bending angles of bunch compressors are selected as variables. Various beam parameters computed by ELEGANT were used as objectives. By using MOGA, new linac lattice designs with 2 and 3 bunch compressors was generated and their beam properties are presented in this paper.

TUPPC033

Random Walk Optimization in Accelerators: Vertical Emittance Tuning at SLS

target, emittance, luminosity, controls

1230

M. Aiba, M. Böge, N. Milas, A. Streun
Paul Scherrer Institut, Villigen, Switzerland

The operation of a high performance accelerator is realized only when several beam based corrections are implemented. These corrections are, however, limited by measurement errors as the correction approaches the ideal value. To overcome this limitation, we investigate the application of a random walk (RW) optimization specifically to minimize the vertical emittance at the SLS. A systematic minimization is performed by measuring linear coupling and spurious vertical dispersion and correcting them using 36 skew quadrupole correctors. On the other hand, the minimization can be performed by simply applying a multi-variable optimization from the mathematics point of view, where the best combination of skew corrections is to be found. The measured vertical beam size is available as a stable target function of the minimization even at very low vertical emittance. Although RW and other algorithms are implemented into various accelerator computer codes, it is interesting to apply this concept to the real machine, where measurement errors are unavoidable and may prohibit systematic minimization based on a machine model. Possible applications of the technique in general are also discussed.

TUPPC035

Design of a Surface Muon Beam Line for High Field muSR at the PSI Proton Accelerator Facility

simulation, focusing, proton, secondary-beams

1236

D. Reggiani, K. Deiters, P. Kaufmann, Y. Lee, T. Prokscha, T. Rauber, R. Scheuermann, K. Sedlak, V. Vranković
Paul Scherrer Institut, Villigen, Switzerland

Starting from 2012, a high field muSR (muon spin rotation/relaxation/resonance) facility will come into operation in the piE3 secondary beam line located at the target station E of the PSI proton accelerator. For this purpose, the last part of the beam line has been redesigned in order to integrate two electrostatic spin rotator devices providing a 90° rotation of the muon spin. At the same time, requirements of small beam diameter (σ ≈ 10 mm) as well as small momentum bite (δ_p/p ≈ 1%) in the sample region have to be met. This work focuses on the simulation of the beam optics (28 MeV/c design momentum). Particular concern is given to potential transmission losses caused by the spin rotator devices. The matching of the beam line with the high magnetic field up to 9.5 T surrounding the sample region has been considered as well. An overview of the spin rotator devices, specifically designed for this project, is also presented.

TUPPC036

Integration with the LHC of Electron Interaction Region Optics for a Ring-ring LHeC

proton, dipole, electron, optics

1239

L.N.S. Thompson
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R. Appleby
UMAN, Manchester, United Kingdom
N.R. Bernard
ETH, Zurich, Switzerland
H. Burkhardt, B.J. Holzer
CERN, Geneva, Switzerland
M. Fitterer
KIT, Karlsruhe, Germany
M. Klein
The University of Liverpool, Liverpool, United Kingdom
P. Kostka
DESY Zeuthen, Zeuthen, Germany

The Large Hadron Electron Collider (LHeC) project is a proposal to study e-p and e-A interactions at the LHC. One design uses an electron synchrotron to collide a 60GeV e± beam with the 7TeV proton beam. Designing a new accelerator around the existing LHC machine poses unique challenges, particularly in the interaction region (IR). The electron beam must be quickly separated from the proton beam after the interaction point (IP) to avoid beam-beam effects, while not significantly reducing luminosity or producing large amounts of synchrotron radiation. The proton beam must pass through the electron optics, while the electron beam must avoid the proton optics. The long straight section requires bending in both planes to counteract the IP crossing angle and to displace the beam vertically from the electron machine to the proton IP. An achromatic bending scheme is used in the vertical plane to eliminate dispersion at the IP and provide an optics which is well matched to the LHeC ring lattice. The interaction region and long straight section design is presented and detailed, and the design process and principles discussed.

TUPPC038

Interaction Region Optics for the Non-Interacting LHC Proton Beam at the LHeC

proton, electron, optics, synchrotron

1245

L.N.S. Thompson
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R. Appleby
UMAN, Manchester, United Kingdom
O.S. Brüning, B.J. Holzer
CERN, Geneva, Switzerland
M. Klein
The University of Liverpool, Liverpool, United Kingdom
P. Kostka
DESY Zeuthen, Zeuthen, Germany

The Large Hadron Electron Collider project is a proposal to study e-p and e-A interactions at the LHC. Two electron accelerator designs are being studied; a linac and a synchrotron. In the synchrotron option, a 60GeV electron beam is collided with one of the LHC proton beams to provide high luminosity TeV-scale interactions. The interaction region for this scheme is complex and introduces a series of challenges due to the integration of the two machines. One of these is the optics of the second non-interacting proton beam. The second proton beam must not interfere with the LHeC experiment, but simultaneous running of the remaining LHC experiments requires that this beam must still circulate relatively undisturbed. This paper discusses methods to solve these challenges for the electron synchrotron design.

TUPPC039

Synchrotron Radiation Studies for a Ring-Ring LHeC Interaction Region and Long Straight Section

dipole, electron, proton, synchrotron

1248

L.N.S. Thompson
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R. Appleby
UMAN, Manchester, United Kingdom
N.R. Bernard
ETH, Zurich, Switzerland
O.S. Brüning, B.J. Holzer
CERN, Geneva, Switzerland
M. Klein
The University of Liverpool, Liverpool, United Kingdom
P. Kostka
DESY Zeuthen, Zeuthen, Germany
B. Nagorny
DESY, Hamburg, Germany

The Large Hadron Electron Collider project is a proposal to study e-p and e-A interactions at the LHC. In the design for an electron synchrotron (alternative designs for a linac are also under development), a 60GeV e± beam is collided with a 7TeV LHC proton beam to produce TeV-scale collisions. Despite being much lower energy than the proton beam, the electron beam is high enough energy to produce significant amounts of synchrotron radiation (SR). This places strong constraints on beam optics and bending. In particular challenges arise with the complex geometry required by the long straight section (LSS) and interaction region (IR). This includes the coupled nature of the proton and electron optics, as SR produced by the electron beam must not be allowed to quench the superconducting proton magnets or create problems with beam-gas backgrounds. Despite this, the electron beam must be deflected significantly within the IR to produce sufficient separation from the proton beam.

TUPPC041

A 3 TeV Muon Collider Lattice Design

emittance, lattice, dipole, collider

1254

Y. Alexahin, E. Gianfelice-Wendt
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
A new lattice for 3 TeV c.o.m. energy with β^*=5mm was developed which follows the basic concept of the earlier 1.5 TeV design* but uses quad triplets for the final focus in order to keep the maximum magnet strength and aperture about the same as in 1.5 TeV case. Another difference is employment of combined-function magnets with the goal to lower heat deposition in magnet cold mass and to eliminate regions without bending field which produce “hot spots” of neutrino radiation that can be an issue at higher energy. The proposed lattice is shown to satisfy the requirements on luminosity, dynamic aperture and momentum acceptance.
* Y.Alexahin, E.Gianfelice-Wendt, A.Netepenko, Proc. IPAC10, Kyoto, May 2010, p. 1563

TUPPC042

Effect of Field Errors in Muon Collider IR Magnets on Beam Dynamics

multipole, dipole, sextupole, dynamic-aperture

1257

Y. Alexahin, E. Gianfelice-Wendt, V.V. Kapin
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
In order to achieve peak luminosity of a Muon Collider (MC) in the 10³⁵/cm²/s range very small values of beta-function at the interaction point (IP) are necessary (β^* ~ 5 mm) while the distance from IP to the first quadrupole can not be made shorter than ~6m as dictated by the necessity of detector protection from backgrounds. In the result the beta-function at the final focus quadrupoles can reach 100 km making beam dynamics very sensitive to all kind of errors. In the present report we consider the effects on momentum acceptance and dynamic aperture of multipole field errors in the body of IR dipoles as well as of fringe-fields in both dipoles and quadrupoles in the case of 1.5 TeV (c.o.m.) MC. Analysis shows these effects to be strong but correctable with dedicated multipole correctors.

TUPPC044

Emittance and Phase Space Tomography for the Fermilab Linac

emittance, linac, focusing, optics

1263

C. Johnstone, F.G.G. Garcia, T. Kobilarcik, G.M. Koizumi, C.D. Moore, D.L. Newhart
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Dept. of Energy.
The Fermilab Linac delivers a variable intensity, 400-MeV beam to the The MuCool Test Area experimental hall via a beam line specifically designed to facilitate measurements of the Linac beam emittance and properties. A 10 m, dispersion-free and magnet-free straight utilizes an upstream quadrupole focusing triplet in combination with the necessary in-straight beam diagnostics to fully characterize the transverse beam properties. Since the Linac does not produce a strictly elliptical phase space, tomography must be performed on the profile data to retrieve the actual particle distribution in phase space. This is achieved by rotating the phase space distribution using different waist focusing conditions of the upstream triplet and performing a de-convolution of the profile data. Preliminary measurements using this diagnostic section are reported here.

TUPPC047

New Storage Ring Lattice for the Duke FEL Wiggler Switchyard System

wiggler, lattice, FEL, storage-ring

1272

H. Hao, J.Y. Li, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA

Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
The Duke storage ring is a dedicated drive for the OK-4 FEL and OK-5 FEL, and for the state-of-the-art Compton gamma-ray source, High Intensity Gamma-Ray Source (HIGS). To produce FEL lasing below 190 nm and gamma-ray beams above 100 MeV, the FEL system needs to be upgraded by adding two helical OK-5 wigglers to increase the FEL gain with four OK5 wigglers for the VUV operation. To simultaneously preserve the linear polarization capability of the gamma-ray beam produced by the planar OK-4 FEL, a wiggler switchyard system is under development which will enable the switch between two planar OK-4 wigglers and two helical OK-5 wigglers in the middle of the FEL straight. In this work, we present the new magnetic lattice designed for the operation of the wiggler switchyard system. This new lattice is developed with great flexibility for the operation with different numbers of FEL wigglers, variable betatron tunes, and adjustable electron beam sizes at the collision point for the HIGS. In addition, the new lattice is developed for the operation in a wide range of energies, from 280 MeV to 1.2 GeV, with proper nonlinear dynamics compensations in order to realize a large dynamic aperture.

TUPPC050

Beam Transport and Storage with Cold Neutral Atoms and Molecules

sextupole, solenoid, injection, multipole

1281

P.L. Walstrom, M.D. Di Rosa
LANL, Los Alamos, New Mexico, USA

Funding: US Department of Energy
Paramagnetic neutral atoms and molecules are subject to magnetic-field-gradient forces on their magnetic moments. Li atoms and CaH molecules both have an effective magnetic moment of about one Bohr magneton, and in the presence of a strong (~1 T) magnetic field, acquire a Zeeman energy of one of two values, ±μ|B|. Particles with positive (negative) energy are repelled by (attracted toward) increasing fields. Li and CaH can be laser-cooled to speeds of tens of m/s and the corresponding magnetic fields needed for transport and injection are on the order of 1 T. The stable stored state is the field-repelled state. Many concepts of accelerator physics apply to our neutral particles. The analog of charge-exchange injection into storage rings is laser-based optical pumping from a field-seeking state to a field-repelled state. The role of dipoles in charged-particle optics is played by quadrupoles in neutral particle optics, and the role of quadrupoles by sextupoles. We present our design and tracking results for a neutral atom/molecule accumulator including an injection chicane with a laser-stimulated state-flip.

TUPPC051

FACET Tolerances for Static and Dynamic Misalignment

plasma, sextupole, simulation, wakefield

1284

J.T. Frederico, M.J. Hogan, T.O. Raubenheimer
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
The Facility for Advanced Accelerator and Experimental Tests (FACET) at the SLAC National Accelerator Laboratory is designed to deliver a beam with a transverse spot size on the order of 10 μm x 10 μm in a new beamline constructed at the two kilometer point of the SLAC linac. Commissioning the beamline requires mitigating alignment errors and their effects, which can be significant and result in spot sizes orders of magnitude larger. Sextupole and quadrupole alignment errors in particular can introduce errors in focusing, steering, and dispersion which can result in spot size growth, beta mismatch, and waist movement. Alignment errors due to static misalignments, mechanical jitter, energy jitter, and other physical processes can be analyzed to determine the level of accuracy and precision that the beamline requires. It is important to recognize these effects and their tolerances in order to deliver a beam as designed.

TUPPC054

Beam Acceleration by a Multicell RF Cavity Structure Proposed for Improved Yield in Hydroforming

cavity, electron, acceleration, focusing

1293

J.A. Holmes, Y.W. Kang
ORNL, Oak Ridge, Tennessee, USA
A.E. Fathy, K.R. Shin
University of Tennessee, Knoxville, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
We study the accelerating properties of a new multicell cavity structure with irises forming a rectangular aperture between the cavity cells. We are interested in this structure because, from a mechanical point of view, the rectangular iris may make possible a much improved structure quality using a hydroforming manufacturing process. RF analysis shows that the rectangular iris shape provides asymmetric transverse focusing per half RF period. If the horizontal and vertical rectangular irises are interleaved, the net transverse focusing can be increased. The present studies of the acceleration and transport properties of these cavities are conducted by tracking particles through time-dependent 3D cavity fields from CST MWS using the ORBIT Code.

TUPPC055

Development of an Automatic MATLAB based Emittance Measurement Tool for the IAC Accelerators

emittance, EPICS, background, controls

1296

C.F. Eckman, A. Andrews, Y. Kim, S. Setiniyaz, D.P. Wells
IAC, Pocatello, IDAHO, USA
A.W. Hunt
ISU, Pocatello, Idaho, USA

At the Idaho Accelerator Center (IAC) of Idaho State University, we have been operating fifteen low energy accelerators. To optimize those accelerators properly, we have to measure the transverse beam emittance. To measure the transverse beam emittance of an S-band linear accelerator with the quadrupole scan technique, we installed an Optical Transition Radiation (OTR) screen and a digital CCD camera in the bealime of the accelerator. From the images of the digital CCD camera, the transverse beam profile on the OTR screen can be acquired. To extract the transverse beam size and to estimate the transverse emittance, we have developed a MATLAB program. This paper describe the details of the MATLAB program and performance of our MATLAB based emittance measurement tool.

TUPPC056

Optics Measurements and Corrections at RHIC

optics, proton, luminosity, lattice

1299

M. Bai, J.N. Aronson, M. Blaskiewicz, Y. Luo, V.H. Ranjbar, G. Robert-Demolaize, S.M. White
BNL, Upton, Long Island, New York, USA
G. Vanbavinckhove
CERN, Geneva, Switzerland

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The further improvement of RHIC luminosity performance requires more precise understanding of the RHIC modeling. Hence, it is necessary to minimize the beta-beat, deviation of measured beta function from the calculated beta functions based on an model. The correction of beta-beat also opens up the possibility of exploring operating RHIC polarized protons at a working point near integer, a preferred choice for both luminosity as well as beam polarization. The segment-by-segment technique for reducing beta-beat demonstrated in the LHC operation for reducing the beta-beat was first tested in RHIC during its polarized proton operation in 2011. It was then fully implemented during the RHIC polarized proton operation in 2012. This paper reports the commissioning results. Future plan is also presented.

TUPPC059

Extraction of the Lie Map from Realistic 3D Magnetic Field Map

dipole, extraction, dynamic-aperture, lattice

1308

Y. Li
BNL, Upton, Long Island, New York, USA
X. Huang
SLAC, Menlo Park, California, USA

Funding: Supported by Department of Energy Contract No. DE-AC02-98CH10886.
We present a method to extract the Lie map of any arbitrary accelerator magnet from its actual 3D field map. After fitting a Taylor map from multi-particle tracking trajectories through the actual field, we factorize the map into a Lie map using Dragt-Finn's method. This method is validated by comparing with COSY-infinity for a soft-edge quadrupole model. Applications of extracting symplectic maps for the SPEAR and NSLS-II dipoles are shown as examples. A comparison of the map-tracking results against the direct field-integration-based method also is given.

TUPPC060

Beam Optics and the pp2pp Setup of the STAR Experiment at RHIC

proton, simulation, optics, scattering

1311

P.H. Pile, W. Guryn, J.H. Lee, S. Tepikian, K. Yip
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.
The newly installed forward detector system at the STAR experiment at RHIC measures small angle elastic and inelastic scattering of polarized protons on polarized protons. The detector system makes use of a pair of Roman Pot (RP) detectors, instrumented with silicon detectors, and located on either side of the STAR intersection region downstream of the DX and D0 dipoles and quadrupole triplets. The parallel to point optics is designed so that scattering angles are determined from position measurements at the RP's with small error. The RP setup allows measurement of position and angle for a subset of the scattered protons. These measured position/angle correlations at the RP's can be compared with optics model predictions to get a measure of the accuracy of the quadrupole triplet current settings. The current in each quadrupole in the triplets is comprised of sums and differences of up to six power supplies and an overall 1% error in the triplet field strengths results in a 4% error in four-momentum transfer squared. This technique is also useful to check the polarity of the skew elements located in each quadrupole triplet. Results of the analysis will be presented.

TUPPC061

Commissioning of a beta∗ Knob for Dynamic IR Correction at RHIC

optics, luminosity, feedback, insertion

1314

G. Robert-Demolaize, A. Marusic, S. Tepikian, S.M. White
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.
In addition to the recent optics correction technique demonstrated at CERN and applied at RHIC, it is important to have a separate tool to control the value of the beta functions at the collision point (beta∗). This becomes even more relevant when trying to reach high level of integrated luminosity while dealing with emittance blow-up over the length of a store, or taking advantage of compensation processes like stochastic cooling. Algorithms have been developed to allow modifying independently the beta function in each plane for each beam without significant increase in beam losses. The following reviews the principle of such algorithms and their experimental implementation as a dynamic beta-squeeze procedure.

TUPPC063

The AGS Synchrotron with Four Helical Magnets

injection, resonance, betatron, optics

1320

N. Tsoupas, H. Huang, W.W. MacKay, T. Roser, D. Trbojevic
BNL, Upton, Long Island, New York, USA

Funding: *Work supported by the US Department of Energy.
The idea* of using two partial helical magnets was applied successfully to the AGS synchrotron**, to preserve the proton beam polarization. In this paper we explore in details the idea of using four helical magnets placed symmetrically in the AGS ring. This modification provides many advantages over the present setup of the AGS that uses two partial helical magnets. First, the symmetric placement of the four helical magnets allows for a better control of the AGS optics with reduced values of the beta functions especially near beam injection, second, the vertical spin direction during beam injection and extraction is closer to vertical, and third, it provides a larger “spin tune gap” for the placement of both the vertical and horizontal tunes of the AGS during acceleration, second. Although the same spin gap can be obtained with two partial helices of equal strength, the required strength of the two helices makes it impractical. In this paper we will provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and comparison of these results with the present setup of the AGS that uses two partial helical magnets***.
* T. Roser et al., Proc. EPAC04, p. 1577 (2004).
** H. Huang et al., PRL 99, 154801(2007).
*** N. Tsoupas et. al., these proceedings.

TUPPC069

Third-Order Apochromatic Drift-Quadrupole Beamline

betatron, beam-transport, resonance, focusing

1329

N. Golubeva, V. Balandin, R. Brinkmann, W. Decking
DESY, Hamburg, Germany

We have shown that for every drift-quadrupole system there exists an unique set of Twiss parameters (apochromatic Twiss parameters), which will be transported through that system without first order chromatic distortions*. In this paper we continue the development of the theory of apochromatic focusing and present the design of a straight drift-quadrupole system which can transport apochromatic beam ellipses without influence not only of the second but also of the third order chromatic and geometric aberrations of the beamline transfer map.
* V.Balandin, R.Brinkmann, W.Decking, N.Golubeva. Apochromatic Beam Transport in Drift-Quadrupole Systems. Proceedings of IPAC'10, Kyoto, Japan.

TUPPC070

Alternating Spin Aberration Electrostatic Lattice for EDM Ring

lattice, simulation, proton, storage-ring

1332

Y. Senichev, R. Maier, D. Zyuzin
FZJ, Jülich, Germany
M. Berz
MSU, East Lansing, Michigan, USA

The idea of the electric dipole moment search using the storage ring (SrEDM) with polarized beam is realized under condition of the long-time spin coherency of all particles, the time during which the RMS spread of the spin orientation of all particles in the bunch reaches one radian. Following the requirements of the planned EDM experiment, the SCT should be more than 1000 seconds. During this time each particle performs about 10⁹ turns in the storage ring moving on different trajectories through the optics elements. At such conditions the spin-rotation aberrations associated with various types of space and time dependent nonlinearities start to play a crucial role. In this paper we consider a new method based on the alternating spin drift, causing it to rotate alternately, thereby limiting the growth of aberrations at one order of magnitude lower. As a result, using this method we can achieve the SCT of the order of 5000-6000 seconds. The difficulties of these studies are still in the fact that the aberrations growth observed in the scale of a 10⁹ turns. For the study we use an analytical method in composition with a numerical simulation by COSY Infinity.

TUPPC071

Comparison of Different Numerical Modelling Methods for Beam Dynamics in Electrostatic Rings

simulation, lattice, optics, proton

1335

D. Zyuzin, R. Maier, Y. Senichev
FZJ, Jülich, Germany
S.N. Andrianov, A.N. Ivanov
St. Petersburg State University, St. Petersburg, Russia
M. Berz
MSU, East Lansing, Michigan, USA

To search the electric dipole moment was proposed to use polarized protons at the so-called "magic" momentum of 0.7 GeV/c in an electric storage ring. For studying beam dynamics in electrostatic rings different computational methods can be used. We used differential algebra methods realized in COSY Infinity and integrating program with symplectic Runge-Kutta methods. These methods were observed and compared for orbital and spin motion.

TUPPC072

Modeling of Matching Channel for Accelerator Complexes

controls, lattice, booster, dipole

1338

E.A. Podzyvalov, S.N. Andrianov
St. Petersburg State University, St. Petersburg, Russia
D. Zyuzin
FZJ, Jülich, Germany

Practically modern accelerator facility can be considered as a composite machines. Therefore it is necessary to consider special matching channels to joint all accelerator components together. For such channels advance various requirements, which can be formulated in the form of criteria sets. In this paper considered a global optimization concept allows to find appropriate solutions sets. This approach is demonstrated on the problem of modeling the matching channels for NICA accelerator complex.

TUPPC079

Tracking LHC Models with Thick Lens Quadrupoles: Results and Comparisons with the Standard Thin Lens Tracking

lattice, simulation, optics, dipole

1356

M. Giovannozzi, H. Burkhardt, T. Risselada
CERN, Geneva, Switzerland

So far, the massive numerical simulation studies of the LHC dynamic aperture were performed using thin lens models of the machine. This approach has the clear advantage of speed, but it has also the disadvantage of requiring re-matching of the optics from the real thick configuration to the thin one. Furthermore, as the figure-of-merit for the re-matching is the agreement between the beta-functions for the two model, while the quadrupole gradients are left free parameters, the effect of the magnetic multipoles might be affected by this approach and in turn the dynamic aperture computation. In this paper the new approach is described and the results for the dynamic aperture are compared with the old approach, including detailed considerations on the CPU-time requirements.

TUPPC101

A Model of the AGS Based on Stepwise Ray-Tracing Through the Measured Field Maps of the Main Magnets

resonance, sextupole, focusing, simulation

1395

Y. Dutheil, F. Méot, N. Tsoupas
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.
Two dimensional mid-plane magnetic field maps of two of the main AGS magnets were produced, from Hall probe measurements, for a series of different current settings. The analysis of these data yielded the excitation functions and harmonic coefficients of the main magnets [BNL TN 424 & TN 429] which have been used so far in all the models of the AGS. The constant increase of computation power makes it possible today to directly use stepwise ray-tracing through these measured field maps with a reasonable computation time. We describe in detail how these field maps have allowed generation of models of the 6 different types of AGS main magnets, and how they are being handled with the Zgoubi ray-tracing code. We give and discuss a number of results so obtained regarding both beam and spin dynamics in the AGS, and provide comparisons with other numerical and analytical modeling methods.

TUPPD008

Recent Progress Toward a Muon Recirculating Linear Accelerator

linac, dipole, cryomodule, factory

1422

K.B. Beard
Muons, Inc, Batavia, USA
M. Aslaninejad, C. Bonţoiu, A. Kurup, J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
S.A. Bogacz, V.S. Morozov, Y. Roblin
JLAB, Newport News, Virginia, USA

Both Neutrino Factories (NF) and Muon Colliders (MC) require very rapid acceleration due to the short lifetime of muons. After a capture and bunching section, a linac raises the energy to about 900 MeV, and is followed by one or more Recirculating Linear Accelerators (RLA), possibly followed by a Rapid Cycling Synchrotron (RCS) or Fixed-Field Alternating Gradient (FFAG) ring. A RLA reuses the expensive RF linac section for a number of passes at the price of having to deal with different energies within the same linac. Various techniques including pulsed focusing quadrupoles, beta frequency beating, and multipass arcs have been investigated via simulations to improve the performance and reduce the cost of such RLAs.

TUPPD011

Studies of the Twin Helix Parametric-resonance Ionization Cooling Channel with COSY INFINITY

simulation, resonance, emittance, collider

1428

J.A. Maloney, K.B. Beard, R.P. Johnson
Muons, Inc, Batavia, USA
A. Afanasev
GWU, Washington, USA
S.A. Bogacz, Y.S. Derbenev, V.S. Morozov
JLAB, Newport News, Virginia, USA
B. Erdelyi
Northern Illinois University, DeKalb, Illinois, USA

Funding: Supported in part by SBIR Grant DE-SC00005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A primary technical challenge to the design of a high luminosity muon collider is an effective beam cooling system. An epicyclic twin-helix channel utilizing parametric-resonance ionization cooling has been proposed for the final 6D cooling stage. A proposed design of this twin-helix channel is presented that utilizes correlated optics between the horizontal and vertical betatron periods to simultaneously focus transverse motion of the beam in both planes. Parametric resonance is induced in both planes via a system of helical quadrupole harmonics. Ionization cooling is achieved via periodically placed wedges of absorbing material, with intermittent rf cavities restoring longitudinal momentum necessary to maintain stable orbit of the beam. COSY INFINITY is utilized to simulate the theory at first order. The motion of particles around a hyperbolic fixed point is tracked. Comparison is made between the EPIC cooling channel and standard ionization cooling effects. Cooling effects are measured, after including stochastic effects, for both a single particle and a distribution of particles.

TUPPD020

An EMMA Racetrack

dipole, injection, extraction, electron

1452

B.D. Muratori, J.K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.L. Owen
UMAN, Manchester, United Kingdom

EMMA (Electron Machine for Many Applications) is the world’s first prototype non-scaling electron FFAG hosted at Daresbury Laboratory. Several upgrade possibilities for EMMA are explored, from creating a dispersion-free region in the ring to facilitate injection and extraction to making an insertion in EMMA by turning it into a racetrack-style machine. Alternative methods of injection and extraction into the EMMA ring are explored together with their feasibility and implications. The option of developing nested racetracks to achieve a particular desired energy is also explored.

TUPPD021

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

closed-orbit, 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.

TUPPD026

Study of the RFQ Beam Cooler for SPES project

ion, rfq, emittance, extraction

1467

M.M. Maggiore, A.M. Porcellato, S. Stark
INFN/LNL, Legnaro (PD), Italy

The SPES project is the new Radioactive Ion Beam facility under construction at Laboratori Nazionali of Legnaro, Italy. In this framework in order to improve the beam quality in terms of emittance and energy spread, a study of a new RFQ beam cooler device is accomplishing. The electromagnetic design of the RFQ section and the electrostatic layout of the injection and extraction regions have been done. The study about the beam dynamic is going on by means of dedicated codes which allow to take into account the interaction of the ions with the buffer gas needed to cool the beams. The status of the project and the results will be shown in this report.

TUPPD075

Simulated Performance of the Wisconsin Superconducting Electron Gun

emittance, solenoid, simulation, focusing

1572

R.A. Bosch, K.J. Kleman
UW-Madison/SRC, Madison, Wisconsin, USA
R.A. Legg
JLAB, Newport News, Virginia, USA

The Wisconsin superconducting electron gun is modeled with multiparticle tracking simulations using the ASTRA and GPT codes. To specify the construction of the emittance-compensation solenoid, we studied the dependence of the output bunch's emittance upon the solenoid's strength and field errors. We also evaluated the dependence of the output bunch's emittance upon the bunch's initial emittance and the size of the laser spot on the photocathode. The results suggest that a 200-pC bunch with an emittance of about one mm-mrad can be produced for a free-electron laser.

TUPPP002

GLASS Study of the Canadian Light Source Storage Ring Lattice

dynamic-aperture, emittance, lattice, sextupole

1602

W.A. Wurtz, L.O. Dallin
CLS, Saskatoon, Saskatchewan, Canada

GLASS is a technique for finding all potential operating points of a storage ring lattice by examining all possible configurations of the linear lattice. The Canadian Light Source (CLS) storage ring uses three quadrupole families, making it computationally efficient to use GLASS to study the lattice with unbroken symmetry. CLS does not employ harmonic sextupoles and has only two families of chromatic sextupoles. We can exhaust the sextupole degrees of freedom by requiring the horizontal and vertical chromaticities to be both zero. With no remaining free parameters in our lattice, it is possible to calculate dynamic aperture and momentum acceptance for select regions of interest uncovered by the GLASS scan. We find two regions with reasonable dynamic aperture and momentum acceptance: the region where we presently operate and a region that can be accessed by reversing the polarity of one quadrupole family.

TUPPP013

Effects of Multipoles in Dynamic Aperture of the ILSF Storage Ring

multipole, dynamic-aperture, sextupole, lattice

1632

S. Fatehi, E. Ahmadi, F. Saeidi
ILSF, Tehran, Iran
D. Einfeld
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
H. Ghasem
IPM, Tehran, Iran

Dynamic aperture of a synchrotron light source shrinks to small value due to the multipole errors caused by magnet design. In the ILSF storage ring, the tolerance of magnets has been taken into account in the simulation and sextupole magnets reoptimized to improve the dynamic aperture. This paper yields the evaluated dynamic aperture include of multipole errors.

TUPPP014

HiSOR-II, Compact Light Source with a Torus-knot Type Accumulator Ring

lattice, emittance, insertion, insertion-device

1635

A. Miyamoto, S. Sasaki
HSRC, Higashi-Hiroshima, Japan

Funding: This work is partially supported by Cooperative and Supporting Program for Researches and Educations in University sponsored by KEK.
We proposed a torus knot type synchrotron radiation ring where the beam orbit is not closed with one turn but return to the starting position after multiple turns around the ring. This ring is capable of having many straight sections and it is advantageous for installation of insertion devices. We named this architecture AMATELAS. We are designing a new ring based on the shape of a (11, 3) torus knot for our future plan HiSOR-II. This ring has eleven 3.6-m-long straight sections though the ring diameter is as compact as 15 m. The achieved emittance is 17.4 nmrad with the lattice having bending magnets with combined function. This level of emittance is as low as the conventional 3rd generation light source. On the other hand, there is a potential problem caused by that the radius of the orbit and focusing force are not constant in the bending magnets. However, we confirmed that it does not make serious influence to the beam by calculating with dividing the bending into several sections. We will compare the parameters of this new ring with the conventional ring which we have designed as the future plan of our facility and evaluate performance as the compact synchrotron light source.

TUPPP022

Beam Optics Measurements during ALBA Commissioning

lattice, optics, emittance, storage-ring

1656

M. Muñoz, G. Benedetti, J. Campmany, D. Einfeld, Z. Martí
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

The synchrotron light source ALBA is in the final stage of the Storage Ring commissioning, with the beamline commissioning well under way. This paper reviews the results of the modeling of the lattice and the agreement with the LOCO measurement of the machine; the performance of the beta beating correction (critical in the ALBA case due to the large gradient in the bending magnet and the low number of quadrupole families), including effect of insertion devices; the lifetime measurement; tune scans; tune shift with horizontal amplitude; and the general agreement of the machine to the model using during the design. A brief summary of the modeling of the injector chain is included.

TUPPP025

Resurrection of RESOLVE at NSRRC Prepared for the First Turn Beam Steering of the TPS Commissioning

injection, storage-ring, controls, kicker

1665

H.-P. Chang, H.H. Chen, P.C. Chiu, P.J. Chou, K.T. Hsu, S.J. Huang, Y.-C. Liu, F.H. Tseng
NSRRC, Hsinchu, Taiwan

MATLAB based high level application software prepared for the 3GeV Taiwan Photon Source has been built and tested on the 1.5GeV Taiwan Light Source continuously. The RESOLVE program is surveyed and resurrected at NSRRC to support and help the first turn beam steering in the coming commissioning of the TPS accelerator complex. Due to the RESOLVE’s history, it contributed a lot in the past commissioning of SLC at SLAC National Accelerator Laboratory, we believe it may give help although most of the first turn beam steering of current light source machines may pass smoothly with well machine construction. In order to make the revised RESOLVE working, not only the compiling problem but also some memory bugs have been fixed, the updated RESOLVE now can be run on PC/Linux and Mac/OSX computer systems. We are trying to apply and test it on the TLS SR with the turn-by-turn digital BPM system. Some exercises of the error finding in beam steering of the off-axis injection beam are performed for presentation.

TUPPP034

BPM Gains and Beta Function Measurement Using MIA and FPGA BPMs at the APS

betatron, lattice, optics, feedback

1686

C.-X. Wang, G. Decker, H. Shang, C. Yao
ANL, Argonne, USA
D. Ji
IHEP, Beijing, People's Republic of China

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The broadband BPM system at the Advanced Photon Source (APS) is being upgraded with FPGA-based beam history modules, which fix problems in the old history modules and increase functionality. Using these new turn-by-turn BPMs and the newly developed real-time feedback system, measurement of BPM gains, beta function and other optics functions are being developed based on model-independent analysis of turn-by-turn data and model fitting, aiming at quasi-real-time and high-accuracy optics measurement. We will discuss our effort, especially experience with strong nonlinearity and wakefields typical of 3rd-generation light sources.

TUPPP039

Vertical Dispersion Bump Design for Femto-second Slicing Beamline at the ALS

coupling, lattice, emittance, radiation

1698

C. Sun, C. Steier, W. Wan
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Femto-second (fs) slicing beamline has been brought to the operation at the Advanced Light Source (ALS) since 2002. It employs the resonant interaction of an electron bunch with a fs laser beam in a wiggler to energy-modulate a short section of the bunch. The induced energy modulation is then converted to a transverse displacement using a vertical dispersion bump downstream of the wiggler. Thus, the radiation from the fs pulse can be separated from the main bunch radiation. The current dispersion bump design has proved to be an effective and reliable one. However, the ALS storage ring lattice is under an upgrade to improve its brightness. After the completion of the upgrade, a new low emittance will be implemented, and the current dispersion bump design needs to be modified to provide the adequate vertical displacement, while minimizing the vertical emittance and spurious dispersion. In this paper, we present the new design of a vertical dispersion bump using Multi-Objective Genetic Algorithm (MOGA) for the ALS upgrade lattice.

TUPPP065

Progress Report on the SwissFEL Injector Test Facility

emittance, laser, optics, dipole

1747

T. Schietinger, M. Aiba, S. Bettoni, B. Beutner, M. Csatari, K. Doshekenov, Y.-C. Du, M.W. Guetg, C.P. Hauri, R. Ischebeck, F. Le Pimpec, N. Milas, G.L. Orlandi, M. Pedrozzi, P. Peier, E. Prat, S. Reiche, B. Smit, A. Trisorio, C. Vicario
Paul Scherrer Institut, 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. The RF photoinjector facility has been in operation since 2010 and has recently reached its design energy of 250 MeV. A newly installed movable magnetic chicane allows longitudinal bunch compression studies. We report on the first experience with the bunch compressor and present the latest results of projected and slice emittance measurements.

Poster TUPPP065 [1.801 MB]

TUPPP069

A Compact, Modular Electron Beam Delay Line for Use in Novel Free-Electron Laser Schemes

undulator, FEL, electron, lattice

1759

J.K. Jones, J.A. Clarke, N. Thompson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Two Free-Electron Laser (FEL) schemes have been proposed, for the generation of attosecond pulse trains* and for the improvement of the longitudinal coherence of SASE FELs**, in which repeated electron delays are implemented within the undulator lattice. To obtain the maximum performance and flexibility from these schemes it is advantageous to use an electron delay line that satisfies the isochronicity conditions, as well as being compact, modular and, ideally, variable. In this paper we present initial designs for such a system, along with simulations of its performance. We investigate both in-undulator and out-of-undulator designs, and compare the applicability of each for various aspects of the FEL design, as well as commenting on the mechanical and magnetic implications of the schemes.
* N.R. Thompson and B.W.J. McNeil. Phys. Rev. Lett. 100, 203901 (2008).
** N.R. Thompson, D.J. Dunning and B.W.J. McNeil, IPAC2010, TUPE050, p. 2257 (2010).

TUPPR006

Design Progress and Construction Status of SuperKEKB

dipole, status, wiggler, klystron

1822

H. Koiso, K. Akai, K. Oide
KEK, Ibaraki, Japan

KEKB operation finished in June 2010, and the upgrade of KEKB to SuperKEKB has commenced. The design luminosity of SuperKEKB is 8×10³⁵cm^-2s^-1, which is 40 times higher than that of KEKB. The design strategy for SuperKEKB is based on the Nano-Beam Scheme, where the vertical beam sizes of the low-energy positron ring and the high-energy electron ring are squeezed to 50−60 nm at the interaction point with a large Piwinski angle. The beam currents in both rings will be double those in KEKB. Finalizing the design of the interaction region is going on by using precise modeling of beam optics. Dismantling KEKB rings and fabrication of accelerator components for SuperKEKB including magnets, power supplies, and antechamber-type beam pipes have already started. This paper describes design progress and construction status of SuperKEKB.

TUPPR022

Traditional Final Focus System for CLIC

luminosity, lattice, collider, linear-collider

1858

H. Garcia, A. Latina, R. Tomás
CERN, Geneva, Switzerland
H. Garcia
UPC, Barcelona, Spain

Next generation linear colliders needs a very strong focalisation to reach nanometer beam size at the Interaction Point. This task and the chromatic correction generated by the strong lenses is done by the Final Focus System. A traditional Final Focus System based on dedicated chromaticity correction sections is presented as an alternative for CLIC Final Focus. The scheme of the lattice is shown and some tolerances in the Final Doublet are calculated. A systematic tuning using Simplex algorithm and sextupole knobs is performed. The complete comparison to the Local Chromaticity correction scheme is presented.

TUPPR023

Final-Focus Optics for the LHeC Electron Beam Line

synchrotron, radiation, synchrotron-radiation, electron

1861

J.L. Abelleira
EPFL, Lausanne, Switzerland
J.L. Abelleira, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
H. Garcia
UPC, Barcelona, Spain

Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu- CARD, grant agreement no. 227579.
One of the options considered for the ECFA-CERN-NuPECC design study for a Large Hadron electron Collider (LHeC)* based on the LHC is adding a recirculating energy-recovery linac tangential to the LHC. First designs of the electron Final Focus System have shown the need to correct the chromatic aberrations. Two designs using different approaches for the chromaticity correction are compared, namely, the local chromaticity correction** and the traditional approach using dedicated sections.
*LHeC Study Group, “A Large Hadron Electron Collider at CERN,” LHeC-Note 2011-001 (2011).
**J. Abelleria et al., "Design Status of LHeC Linac‐Ring Interaction Region," IPAC2011, p. 2796 (2011).

TUPPR028

Recent Improvements in the Orbit Feedback and Ground Motion Mitigation Techniques for CLIC

luminosity, simulation, feedback, ground-motion

1876

J. Snuverink, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland

The Compact Linear Collider (CLIC) accelerator has strong stability requirements on the position of the beam. In particular, the beam position will be sensitive to ground motion. A number of mitigation techniques have been proposed - quadrupole stabilization and positioning, final doublet stabilization as well as beam based orbit and interaction point (IP) feedback. Integrated studies of the impact of ground motion on the CLIC Main Linac (ML) and Beam Delivery System (BDS) that model the latest hardware designs have been performed. Furthermore, additional imperfections have been introduced and the robustness of this system is discussed in detail. The possibility of using ground motion measurements as an alternative to the quadrupole stabilization is investigated.

TUPPR031

Experimental Verification of the CLIC Decelerator with theTest Beam Line in the CLIC Test Facility 3

extraction, alignment, lattice, linac

1885

R.L. Lillestøl, S. Döbert, M. Olvegård, A. Rabiller, G. Sterbini
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The Test Beam Line in the CLIC Test Facility 3 is the first prototype of the CLIC drive beam decelerator. The main purpose of the experiment is to demonstrate efficient 12 GHz rf power production and stable transport of an electron drive beam during deceleration. The Test Beam Line consists of a FODO structure with high precision BPMs and quadrupoles mounted on mechanical movers for precise beam alignment. Nine out of the planned 16 Power Extraction and Transfer Structures have currently been installed and commissioned. We correlate rf power production measurements with the drive beam deceleration measurements, and compare the two measurements to the theoretical predictions. We also discuss the impact of the drive beam bunch length and bunch combination on the measurements.

TUPPR034

Beam-based Alignment in CTF3 Test Beam Line

alignment, feedback, beam-losses, injection

1894

G. Sterbini, S. Döbert, R.L. Lillestøl, E. Marín, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The CLIC linear collider is based on the two beams acceleration scheme. During acceleration, the drive beam suffers a large increase in its energy spread. In order to efficiently transport such a beam, beam-based alignment techniques together with tight pre-alignment tolerances are crucial. A beam-based steering campaign has been conducted at the Test Beam Line of the CLIC Test Facility to evaluate the performance of several algorithms. In the following we present and discuss the obtained results.

TUPPR035

A Comparative Study for the CLIC Drive Beam Decelerator Optics

optics, injection, alignment, lattice

1897

G. Sterbini, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The baseline for the CLIC drive beam decelerators optics consists of a 2-m-long FODO cell. This solution was adopted to have strong focusing in order to mitigate the effect of the PETS wakefields and to minimize the drive beam envelope. Taking into account the most recent PETS design, we compare the performance of the baseline FODO cell with a proposal that consider twice longer FODO cell. Despite of the expected cost in term of performance, the reduction of the complexity of the system due to the halving of the number of quadrupoles can be beneficial for the overall optimization of the decelerator design.

TUPPR052

3D FEA Computation of the CLIC Machine Detector Interface Magnets

solenoid, simulation, shielding, luminosity

1936

A. Bartalesi, M. Modena
CERN, Geneva, Switzerland

A critical aspect of the Compact Linear Collider (CLIC) design is represented by the Accelerator/Experiment interface (called Machine Detector Interface or MDI). In the 3 TeV CLIC layout, the final focus QD0 quadrupole will be located inside the end-cap of the detector itself. This complex MDI scenario required to be simulated with a full 3D-FE analysis. This study was critical to check and control the magnetic cross-talk between the Detector Solenoid and the final Focus QD0 magnet and therefore to optimize the design of an “antisolenoids” system needed to shield the QD0 and the e⁻/e⁺ beams from the detector magnetic field. In this paper the development and evolution of the computational FE model is presented together with the results obtained and their implication on the CLIC MDI Design.

TUPPR056

Parametric Study of the CLIC Damping Rings Delay Ring for Reaching Isochronicity Conditions

dipole, sextupole, damping, optics

1948

P. Zisopoulos, F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland

A delay ring in the CLIC damping rings complex is necessary for recombining the two trains to one with the nominal bunch separation of 0.5ns. The preservation of the longitudinal bunch distribution demands an optics design, which eliminates momentum compaction factor up to high order, allowing the delay ring to function under isochronous conditions. Taking into account thin lens approximation, a qualitative estimation of parameters of the cell that will be used in the delay ring, is given, so as to obtain isochronicity conditions. Considerations on the possibility of tuning the cell under those requirements are finally presented.

TUPPR060

Detection of Ground Motion Effects on the Beam Trajectory at ATF2

ground-motion, lattice, extraction, linear-collider

1954

Y. Renier, J. Pfingstner, D. Schulte, R. Tomás
CERN, Geneva, Switzerland

The ATF2 experiment is currently demonstrating the feasibility of the beam delivery system for the future linear collider. The tunning is very critical to obtain the nanometer vertical beam size at the interaction point and in the case of CLIC, ground motion effects on the beam must be corrected. In this respect, as a proof of principle of a ground motion feed forward, the ground motion effects on the beam trajectory are extracted from the beam position monitor readings.

TUPPR068

The Achromatic Telescopic Squeezing Scheme: Basic Principles and First Demonstration at the LHC

optics, sextupole, injection, insertion

1978

S.D. Fartoukh, R. De Maria, B. Goddard, W. Höfle, M. Lamont, G.J. Müller, L. Ponce, S. Redaelli, R.J. Steinhagen, M. Strzelczyk, R. Tomás, G. Vanbavinckhove, J. Wenninger
CERN, Geneva, Switzerland
R. Miyamoto
ESS, Lund, Sweden

The Achromatic Telescopic Squeezing (ATS) scheme [1] is a novel squeezing mechanism enabling the production of very low β^* in circular colliders. The basic principles of the ATS scheme will be reviewed together with its strong justification for the High-Luminosity LHC Project. In this context, a few dedicated beam experiments were meticulously prepared and took place at the LHC in 2011. The results obtained will be highlighted, demonstrating already the potential of the ATS scheme for any upgrade project relying on a strong reduction of β^*.
[1] S. Fartoukh, "An Achromatic Telescopic Squeezing (ATS) Scheme For The LHC Upgrade," IPAC'11, WEPC037, p. 2088 (2001).

TUPPR075

Challenges for the Magnet System of LHeC

electron, proton, linac, dipole

1996

S. Russenschuck, B.J. Holzer, G. Kirby, A. Milanese, R. Tomás, D. Tommasini, F. Zimmermann
CERN, Geneva, Switzerland

The main challenges for the normal conducting magnet system are the very compact, low field, and high precision magnets for the ring-ring option and their rapid installation in the crowded LHC tunnel. The superconducting triplet magnets require strong gradients for the protons in close vicinity of a field-free region for the electrons. The field requirements for the ring-ring option allow a number of different magnet designs using the well-proven Nb-Ti superconductor technology and making use of the cable development for the LHC. The separation distance between the electron and proton beams in Q1 requires a half-aperture quadrupole design to limit the overall synchrotron radiation power emitted by the bending of the electron beam. The requirements in terms of aperture and field gradient are more difficult to obtain for the Linac-Ring option. Consequently we present the limitations for the field gradient and septum size achievable with both Nb-Ti and Nb3Sn superconducting technologies.

TUPPR085

Recycler Chromaticities and End Shims for NOvA at Fermilab

lattice, sextupole, dynamic-aperture, dipole

2023

M. Xiao
Fermilab, Batavia, USA

In era of NOvA operation, it is planned to slip-stack six on six Booster proton batches in the Recycler ring for a total intensity of 5×10¹³ protons/cycle. During the slip-stacking, the chromaticities are required to be jumped from (-2,-2) to (-20,-20). However, they can only be adjusted to (-12,-12) from (-2,-2) using existing 2 families of powered sextupoles. On the other hand, the presently designed Recycler lattice for Nova replaces the 30 straight section with 8 “D-D half FODO cells”. We use 3 quads in a half-cell to obtain the working point under the limit of the feasible quad strength, and the maximum beta-function in this section cannot be less than 80 m. In this paper, we re-designed the end shims of the permanent magnets in the ring lattice with appropriate quadrupole and sextupole components to meet both chromaticity and tune requirements. We are able to use 2 quads in a half cell in RR30 straight section within feasible quad strength. The maximum beta-functions are also lowered to around 55 m. The dynamic aperture tracking has been done using MAD to simulate the scenario of beam injection into the Recycler ring for Nova.

WEYA03

Overview of B-Factories

emittance, sextupole, injection, collider

2086

M.E. Biagini
INFN/LNF, Frascati (Roma), Italy

An overview of the two recently approved high luminosity B-Factories, the SuperB in Italy and the SuperKEKB in Japan, will be presented. The main design features to reach the very high luminosity requested and a status of progress in design and construction will be given.

Slides WEYA03 [6.151 MB]

WEOAA01

Injected Beam Imaging at SPEAR 3 with a Digital Optic Mask

injection, synchrotron, storage-ring, target

2116

H.D. Zhang, R.B. Fiorito, A.G. Shkvarunets
UMD, College Park, Maryland, USA
W.J. Corbett, A.S. Fisher, K. Tian
SLAC, Menlo Park, California, USA

Funding: *This work is partially funded by the Office of Naval Research and the DOD Joint Technology Office.
At SPEAR3, the light source operates in top-up injection mode with 273nC charge circulating in the storage ring (350mA). Each individual injection pulse contains only 40pC, or a contrast ration of 1:6800. In order to monitor injected beam dynamics during User operations, it is desirable to optically image the injected charge distribution on a turn-by-turn basis in the presence of the bright stored beam. The measurement is made by re-imaging visible synchrotron radiation onto a 1024x768 pixel Digital-Micro-Array mirror device (DMD) which is used to 'mask' light from the central stored beam while observing the weak injected beam signal on an intensified, fast-gated CCD camera. Complex beam dynamics are observed after only a few 10's of turns around the synchrotron. In this paper we report on the DMD optical configuration, masking considerations, measurement timing and initial tests imaging the injected beam in the presence of stored beam.

Slides WEOAA01 [1.874 MB]

WEEPPB013

Direct Wind Superconducting Corrector Magnets for the SuperKEKB IR

dipole, octupole, background, multipole

2191

B. Parker, M. Anerella, J. Escallier, A.K. Ghosh, A.K. Jain, A. Marone, P. Wanderer
BNL, Upton, Long Island, New York, USA
Y. Arimoto, M. Iwasaki, N. Ohuchi, M. Tawada, K. Tsuchiya, H. Yamaoka, Z.G. Zong
KEK, Ibaraki, Japan

Upgrade of the KEKB asymmetric e⁺e⁻ collider for a forty-fold luminosity increase, denoted SuperKEKB, is now underway. For SuperKEKB the beam crossing angle is increased to provide separate focusing channels for the incoming and outgoing electron and positrons beams in new superconducting Interaction Region (IR) magnets. Two functional classes of superconducting corrector magnets are needed to meet SuperKEKB beam optics goals. Dipole, skew-dipole, skew-quadrupole and octupole coil windings will be inserted inside the bores of the main IR quadrupoles to make magnet center alignments, roll adjustments and non-linear optics corrections. A second class of high-order magnetic multipole corrector coils is needed to compensate the non-linear fringe field experienced by the circulating beam that passes just outside the main quadrupole coils that are closest to the Interaction Point (IP). Near the IP there is no space for magnetic yokes or other passive shielding to diminish the fringe field. At the time of this conference the SuperKEKB corrector magnet production will be under way. The SuperKEKB correction coil design and our production technique are reviewed in this paper.

WEEPPB014

The Magnetic Model of the LHC during the 3.5 TeV Run

injection, dipole, controls, optics

2194

E. Todesco, N. Aquilina, M. Giovannozzi, M. Lamont, F. Schmidt, R.J. Steinhagen, M. Strzelczyk, R. Tomás
CERN, Geneva, Switzerland
N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta

The magnetic model of the LHC is based on a fit of the magnetic measurements through equations that model the field components (geometric, saturation, persistent) at different currents. In this paper we will review the main results related to the magnetic model during the run of the LHC in 2010-2011: with a top energy of 3.5 TeV, all components of the model but the saturation are visible. We first give an estimate of the reproducibility of the main components and multipolar errors as they can be deduced from beam measurements, i.e. orbit, tune, chromaticity, beta beating and coupling. We then review the main results relative to the decay at injection plateau, dependence on powering history, and snapback at the beginning of the ramp for both tune and chromaticity. We discuss the precision obtained in tracking the magnets during the ramp, where the persistent current components gradually disappear. We conclude by presenting the behaviour of the quadrupoles model during the squeeze. A list of the major changes implemented during the operation together with what are considered as the main open issues is given.

WEPPC030

Second Sound Measurement Using SMD Resistors to Simulate Quench Locations on the 704 MHz Single-cell Cavity at CERN

cavity, simulation, cryogenics, linac

2269

K.C. Liao, O. Brunner, E. Ciapala, T. Junginger, W. Weingarten
CERN, Geneva, Switzerland

Oscillating superleak transducers (OSTs) containing a flexible porous membrane are widely used to detect the so-called second sound temperature wave when a quench event occurs in a superconducting RF cavity. In principle, from the measured speed of this wave and the travel time between the quench event and several OSTs, the location of the quench sites can be derived by triangulation. Second sound behavior has been simulated though different surface mount (SMD) resistors setups on a Superconducting Proton Linac (SPL) test cavity, to help understand the underlying physics and improve quench localisation. Experiments are described that have been conducted to search for explanation of heat transfer mechanism during cavity quench that causes contradictory triangulation results.

Poster WEPPC030 [1.473 MB]

WEPPC033

RF and Surface Properties of Bulk Niobium and Niobium Film Samples

niobium, electron, collider, photon

2278

T. Junginger, W. Weingarten
CERN, Geneva, Switzerland
R. Seviour
University of Huddersfield, Huddersfield, United Kingdom
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Work supported by the German Doctoral Students program of the Federal Ministry of Education and Research (BMBF)
The surface resistance Rs of superconducting cavities can be obtained from the unloaded quality factor Q0. Since RS varies strongly over the cavity surface its value must be interpreted as averaged over the whole cavity surface. A more convenient way to investigate the surface resistance of superconducting materials is therefore to examine small samples, because they can be manufactured cheaply, duplicated easily and used for further surface analyses. At CERN a compact Quadrupole Resonator has been developed for the RF characterization of superconducting samples at different frequencies. In this contribution, results from measurements on bulk niobium and niobium film on copper samples are presented. Different models accounting for the field depended surface resistance are being confronted by the experimental results. The RF results are being correlated to surface analyses measurements carried out on the same samples.

WEPPC037

A Ring-shaped Center Conductor Geometry for a Half-wave Resonator

impedance, cavity, linac, ion

2289

B. Mustapha, Z.A. Conway, P.N. Ostroumov
ANL, Argonne, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract DE-AC02-06CH11357.
Half-wave resonators (HWR) are used and being proposed for the acceleration of high-intensity proton and heavy-ion beams in the 0.1 < β < 0.5 velocity range. The highest performing half-wave resonator geometries use a center conductor with a race-track shaped cross section in the high-electric field region; a feature shared with spoke cavities which are also being proposed for the same velocity regime. We here propose a ring-shaped center conductor instead of the race-track shape. Preliminary studies show that the ring geometry has a similar peak surface electric field as the race-track one, but has several other advantages. In particular, the ring-shaped geometry has: a lower peak surface magnetic field, a much higher Shunt impedance for the same peak fields, and no quadrupole electric field asymmetry which has been observed in the race-track geometry. In a solenoid-based symmetric focusing, the quadrupole component may lead to unnecessary emittance growth which is not acceptable in high-intensity ion linacs. We will present a detailed comparison and a discussion of the two geometries.

WEPPC044

Multipole Effects Study for Project X Front End Cavities

cavity, multipole, linac, focusing

2309

P. Berrutti, M.H. Awida, I.V. Gonin, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, USA

Effects of RF field asymmetry along with multipoles have been studied in Project X front end cavities. One family of half wave resonators operating at 162.5 and two of spoke resonators operating at 325 MHz have been analysed. HWR and spoke resonators unlike elliptical cavities, do not have axial symmetry, hence a quadrupole perturbation to the beam is present. The purpose of this paper is to explain the approach and the calculation method used to understand and overcome the drawbacks due to the RF field asymmetry.

WEPPC053

SSR1 HOM Analysis and Measurements

HOM, dipole, cavity, higher-order-mode

2333

M.H. Awida, P. Berrutti, I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Single spoke resonators (SSR1, β=0.22) are currently under development for Project X at Fermilab. In this paper, extensive Higher Order Mode (HOM) analysis carried out on SSR1 is reported including the simulated R/Q for monopoles, dipoles, and quadrupoles. HOM measurements carried out on several spoke cavities are also reported including the harmonic response and the bead pull measurements. Comparison between the measured R/Q values and the simulated ones are presented.

WEPPD011

Study of the Pressure Profile Inside the NEG Coated Chambers of the SIS 18

vacuum, dipole, simulation, ion

2519

M.C. Bellachioma, H. Kollmus, A. Krämer, J. Kurdal, H. Reich-Sprenger, L. Urban, M. Wengenroth
GSI, Darmstadt, Germany

In the context of the technical developments for the construction of FAIR at GSI, an intensive programme for the vacuum upgrade of the existing SIS 18 was started in 2005, with the aim to improve the beam lifetime and intensity. To reach these purposes also the installation of NEG coated dipole and quadrupole chambers is foreseen. During the upgrade shutdowns performed between 2006 and 2009 the vacuum chambers of approximately 65% of the SIS18 circumference were replaced by NEG coated pipes. To evaluate in detail the pressure profile inside the coated chambers mounted into the accelerator a dedicated experimental set-up, which reproduces a vacuum environment similar to the one of the SIS 18, was built. Using three gauges, mounted in different positions of a coated chamber, it was possible to measure the pressure in the range of 10^-12 mbar inside the activated NEG pipe and 10^-11 mbar outside the pipe at the pumping posts. Additionally, a modelling of a SIS18 vacuum sector was realised and the pressure variation values obtained by a Monte-Carlo simulation were compared with those measured. In this paper the experimental results and the vacuum simulations are described and discussed.

WEPPD077

Generation of Picosecond Electron-bunch Trains with Variable Spacing Using a Multi-pulse Photocathode Laser

laser, electron, wakefield, simulation

2705

P. Piot
Fermilab, Batavia, USA
M.E. Conde, W. Gai, C.-J. Jing, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof
ANL, Argonne, USA
D. Mihalcea, P. Piot, M.M. Rihaoui
Northern Illinois University, DeKalb, Illinois, USA

Funding: Work supported by DOE awards FG-02-08ER41532 and DE-AC02-06CH11357.
We demonstrate the generation of a train of electron bunches with variable spacing at the Argonne Wakefield Accelerator. The photocathode ultraviolet laser pulse consists of a train of four pulses produced via polarization splitting using two alpha-BBO crystals. The photoemitted electron bunches are then manipulated in a horizontally-bending dogleg with variable longitudinal dispersion. A downstream vertically-deflecting cavity is then used to diagnose the temporal profile of the electron beam. The generation of a train composed of four bunches with tunable spacing is demonstrated. Such train of bunch could have application to, e.g., the resonant excitation of wakefield in dielectric-lined waveguides.

WEPPP005

Progress on Muon Parametric-resonance Ionization Cooling Channel Development

resonance, emittance, simulation, betatron

2729

V.S. Morozov, Y.S. Derbenev
JLAB, Newport News, Virginia, USA
A. Afanasev
GWU, Washington, USA
K.B. Beard, R.P. Johnson
Muons, Inc, Batavia, USA
B. Erdelyi, J.A. Maloney
Northern Illinois University, DeKalb, Illinois, USA

Funding: Supported in part by DOE SBIR grant DE-SC0005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Parametric-resonance Ionization Cooling (PIC) is intended as the final 6D cooling stage of a high-luminosity muon collider. To implement PIC, a continuous-field twin-helix magnetic channel was developed. A 6D cooling with stochastic effects off is demonstrated in a GEANT4/G4beamline model of a system where wedge-shaped Be absorbers are placed at the appropriate dispersion points in the twin-helix channel and are followed by short rf cavities. To proceed to cooling simulations with stochastics on, compensation of the beam aberrations from one absorber to another is required. Initial results on aberration compensation using a set of various-order continuous multipole fields are presented. As another avenue to mitigate the aberration effect, we optimize the cooling channel’s period length. We observe a parasitic parametric resonance naturally occurring in the channel’s horizontal plane due to the periodic beam energy modulation caused by the absorbers and rf. We discuss options for compensating this resonance and/or properly combining it with the induced half-integer parametric resonance needed for PIC.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

WEPPP015

Generation and Characterization of 5-micron Electron Beam for Probing Optical Scale Structures

electron, diagnostics, permanent-magnet, target

2753

M.G. Fedurin, M. Babzien, V. Yakimenko
BNL, Upton, Long Island, New York, USA
B.A. Allen
USC, Los Angeles, California, USA
P. Muggli
MPI, Muenchen, Germany
A.Y. Murokh
RadiaBeam, Santa Monica, USA

In recent years advanced acceleration technologies have progress toward combination of electron beam, laser and optical scale dielectric structures. In present paper described generation of the electron beam probe with parameters satisfied to perform test of such optical structures.

WEPPP064

Design and Simulation of the Stripline Transverse Quadrupole Kicker for HLS II

kicker, impedance, dipole, storage-ring

2852

F.F. Wu, W.B. Li, P. Lu, T.J. Ma, B.G. Sun, Y.Y. Xiao, H. Xu, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

In order to investigate the possibility of excite a transverse quadrupole mode oscillation of the electron bunch in the HLS II storage ring, we design a stripline transverse quadrupole kicker. The characteristic impedance of some modes(dipole modes, sum mode, quadrupole mode) of the optimised stripline kicker must match 50Ω characteristic impedance of the external transmission lines so as to reduce the reflected power. We use nonlinear least square method to optimise the kicker and compare characteristic impedances of calculation using 2D Possion code and fitted function of several variables, then we get optimised size with integrated use of Possion code and fitted function of several variables. Using the 2D Poisson code, we simulate the electric field distribution of dipole modes when the horizontal or the vertical electrodes are at opposite unit potentials, and the electric field distribution of quadrupole mode using quadrupole kick. We verified that the designed stripline kicker can excite a transverse quadrupole mode oscillation of the electron bunch.

WEPPP083

Near Real-time Response Matrix Calibration for 10-Hz GOFB

feedback, dipole, damping, injection

2903

C. Liu, R.L. Hulsart, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty
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.
The 10-Hz global orbit feedback, for damping the trajectory perturbation (~10 Hz) due to the vibrations of the triplets, is operational for injection and store in RHIC. The operation of the system has been performed using transfer functions between the beam position monitors and correctors obtained from the online optics model and a correction algorithm based on singular value decomposition (SVD). Calibration of the transfer functions by measuring the beam position oscillations while modulating the dedicated correctors has been carried out. The feedback results with model matrix and measured matrix will be compared.

WEPPP085

Study on the Realignment Plan for J-PARC 3 GeV RCS after the Tohoku Earthquake in Japan

injection, extraction, survey, alignment

2909

N. Tani, H. Hotchi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

J-PARC 3GeV RCS suffered the big damage to its building and cooling and electric facilities by the Tohoku Region Pacific Coast Earthquake on March 11, 2011. After the earthquake, RCS magnets were measured to confirm the state of accelerator beam line. As a result, it was found out that there was an alignment error of several millimeters in both horizontal and vertical directions that caused a deformation in the J-PARC 3GeV RCS tunnel. In this paper, we report the survey result in the accelerator tunnel after the earthquake and the realignment plan for J-PARC 3GeV RCS.

WEPPP087

The Improvement and Test of Laser Positioning System for TPS Magnets Alignment Inspection

laser, alignment, sextupole, insertion

2915

M.L. Chen, J.-R. Chen, H.C. Ho, K.H. Hsu, W.Y. Lai, C.-S. Lin, C.J. Lin, H.C. Lin, H.M. Luo, S.Y. Perng, P.L. Sung, Y.L. Tsai, T.C. Tseng, H.S. Wang, M.H. Wu
NSRRC, Hsinchu, Taiwan

A Laser positioning system, consist of a laser, laser position sensing devices (PSD) module and two granite blocks, is developed for the alignment inspection of TPS (Taiwan Photon Source) quadrupole and sextupole magnets during installation on a girder. The PSD module is adapted on the pole center of magnet and is designed to stand for mechanical center of magnets. For high accuracy, eliminating the influence of magnets manufacturing errors between PSD module is a major work. The PSD is mounted on a precise diameter expansible jig to absorb the manufacturing errors. The real roundness of the expansible jig can keep under 3um when diameter is expanded 80um. The PSD position is adjusted and corrected in advance, and then the PSD module center can be identical to the ideal pole position of magnets on the girder within 15um. The magnet will be aligned and adjusted by laser position on PSD. This paper describes how to eliminate the measuring error caused by magnet manufacturing error and the detail of alignment inspection procedure of magnets during the installation on a girder.

WEPPR004

Effect of Beam-beam Interactions on Stability of Coherent Oscillations in a Muon Collider

collider, luminosity, resonance, lattice

2940

K. Ohmi
KEK, Ibaraki, Japan
Y. Alexahin
Fermilab, Batavia, USA

In order to achieve the peak luminosity of a muon collider in the 10³⁵ cm^-2 s^-1 range the number of muons per bunch should be of the order of a few units of 10¹² rendering the beam-beam parameter as high as 0.1 per IP. Such strong beam-beam interaction can be a source of instability if the working point is chosen close to a coherent beam-beam resonance. On the other hand, the beam-beam tune spread can provide a mechanism of suppression of the beam-wall driven instabilities. In this report the coherent instabilities driven by beam-beam and beam-wall interactions are studied with the help of BBSS code for the case of 1.5 TeV c.o.m muon collider.

WEPPR019

Catalogue of Losses for the IFMIF Prototype Accelerator

rfq, linac, SRF, solenoid

2982

P.A.P. Nghiem, N. Chauvin, D. Uriot
CEA/DSM/IRFU, France
M. Comunian
INFN/LNL, Legnaro (PD), Italy
C. Oliver
CIEMAT, Madrid, Spain

For machine and personal protection purposes, precise knowledge of beam loss location and power are crucial, especially in a high intensity, high power accelerator like the IFMIF prototype. This paper aims at discussing the protocol of appropriate studies in order to give the catalogue of beam losses in different conditions: nominal, tuning and accidental. Then results of these studies are given.

WEPPR027

Complete Electromagnetic Design of the ESS-Bilbao RFQ Cold Model

rfq, dipole, simulation, radio-frequency

2991

A. Vélez, I. Bustinduy, J. Feuchtwanger, N. Garmendia, O. González, I. Madariaga, J.L. Muñoz, D. de Cos
ESS Bilbao, Bilbao, Spain
F.J. Bermejo
Bilbao, Faculty of Science and Technology, Bilbao, Spain
V. Etxebarria, J. Portilla
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain

In this work, the ESS-Bilbao 352,2 Mhz RFQ Cold Model to be built in the ESS-Bilbao accelerator facility is presented. The Cold Model intends to be a small scale representation of the final 4 meters long RFQ which will be able to accelerate a 75 mA proton beam from 75 keV to 3 MeV. The work shown here covers the complete electromagnetic design process of the Cold Model which will be built in aluminium with a total length of 1 meter. Moreover, in order to find out fabrication tolerances, a longitudinal test modulation in the vane regions similar to the one designed for the final RFQ is included in the Cold Model. This modulation represents also a useful tool in order to test the agreement between measurements and electromagnetic simulations. In addition, a complete parametric study of the RFQ ends and radial matchers is presented as an important design parameter able to adjust the field flatness. Finally, slug tuning rods are also added to be able to test the tuning procedures. A final RFQ Cold Model prototype has been designed and is currently under fabrication.

WEPPR039

Nonlinear Lattice for Space-Charge Dominated Beam Transport with Suppressed Emittance Growth

focusing, space-charge, emittance, lattice

3021

Y.K. Batygin, A. Scheinker
LANL, Los Alamos, New Mexico, USA

We present a feasible design for the implementation of a beam emittance growth suppressing lattice for space-charge dominated beams. Our analysis is based on original derivations developed in *. We present a FODO focusing channel with quadrupole and duodecapole components which on average create the ﬁeld required to match the high-brightness beam with the structure. Matched beam exhibits smaller emittance growth than that in regular quadrupole focusing channel. Numerical results demonstrate the lattice’s performance in preventing halo formation of a nonuniform space charge dominated beam.
* Y. Batygin, Phys. Rev. E, 57, 5, p. 6020 (1998).

WEPPR040

Intensity Effects of the FACET Beam in the SLAC Linac

linac, emittance, wakefield, alignment

3024

F.-J. Decker, N. Lipkowitz, J. Sheppard, 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 beam for FACET (Facility for Advanced aCcelerator Experimental Tests) at SLAC requires an energy-time correlation ("chirp") along the linac, so it can be compressed in two chicanes, one at the mid point in sector 10 and one W-shaped chicane just before the FACET experimental area. The induced correlation has the opposite sign to the typical used for BNS damping, and therefore any orbit variations away from the center kick the tail of the beam more than the head, causing a shear in the beam and emittance growth. Any dispersion created along the linac has similar effects due to the high (>1.2% rms) energy spread necessary for compression. The initial huge emittances could be reduced by a factor of 10, but were still bigger than expected by a factor of 2-3. Normalized emittance of 2 um-rad in Sector 2 blew up to 150 um-rad in Sector 11 but could be reduced to about 6-12 um-rad for the vertical plane although the results were not very stable. Investigating possible root causes for this, we found locations where up to 10 mm dispersion was created along the linac, which were finally verified with strong steering and up to 7 mm settling of the linac accelerator at these locations.

WEPPR047

The Effect of Non-Zero Closed Orbit on Electron-Cloud Pinch Dynamics

electron, proton, dipole, simulation

3033

G. Franchetti
GSI, Darmstadt, Germany
F. Zimmermann
CERN, Geneva, Switzerland

A study on the pinch dynamics of electron cloud during a bunch passage under the effect of a single arbitrary-order multipole was presented at IPAC2011. The complexity of the pinch pattern is directly related to the order of the multipolar field. However, in a realistic situation, the proton beam will not be located in the center of the vacuum chamber. If the beam is offset a new pinch regime is encountered, where feed-down effects and asymmetry of pinch density render the dynamics more challenging. In this paper we discuss the pinch dynamics with orbit offset, including the resulting orbit variation along a bunch, and address their relevance for the incoherent effect of the electron cloud.

THYA01

High Field Magnet Developments

dipole, luminosity, alignment, collider

3185

T. Nakamoto
KEK, Ibaraki, Japan

Superconducting magnets for future accelerators need to generate a field beyond 10 T. However, mature NbTi superconductors which have been already operated at its performance limit at LHC cannot be adopted. Instead, A15 type superconductors have been considered to be promising materials for the high field magnets. Especially, intensive R&D efforts for the LHC luminosity upgrade with state-of-the-art Nb3Sn superconductors have been carried out. Further future accelerators such as the High-Energy LHC and muon accelerators must require the high field reaching 20 T or more. This means that utilization of HTS (high Tc superconductors) would be the only possible solution. However, it is known that these advanced superconductors are not mechanically robust in comparison with the practical NbTi and the performance is influenced by mechanical stress and strain. In addition, magnetization effects caused by larger effective filament diameters may compromise the field quality in the accelerators. The magnet developments to overcome these issues are ongoing. This presentation will try to review the US and worldwide high field accelerator magnet developments: achievements, status, and plans.

Slides THYA01 [7.578 MB]

THXB03

Beam and Spin Dynamics in an Electric Proton EDM Ring

proton, lattice, dipole, storage-ring

3203

R.M. Talman
CLASSE, Ithaca, New York, USA
J. Talman
BNL, Upton, Long Island, New York, USA

Electric dipole moment (EDM) measurements may help to answer the question ‘‘Why is there more matter than anti-matter in the present universe?'' For a charged baryon like the proton such a measurement is thinkable only in a ring in which a bunch of protons is stored for more than a few minutes, with polarization ‘‘frozen'' (relative to the beam velocity) and with polarization not attenuated by decoherence. Beam and spin dynamics in an all-electric lattice with these characteristics is described. Rings for other charged baryons, such as deuterons or helium-3 nuclei, are also possible but, requiring both electric and magnetic fields, they are more complicated.

Slides THXB03 [0.155 MB]

THPPC010

Beam Start-up of J-PARC Linac after the Tohoku Earthquake

linac, DTL, acceleration, radiation

3293

M. Ikegami, Z. Fang, K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
T. Maruta, A. Miura, H. Sako, J. Tamura, G.H. Wei
JAEA/J-PARC, Tokai-mura, Japan

The beam operation of J-PARC linac was interrupted by the Tohoku earthquake in March 2011. After significant recovering effort including the realignment of most linac components, we have resumed the beam operation of J-PARC linac in December 2011. In this paper, we present the experience in the beam start-up tuning after the earthquake and the status of the linac operation thereafter.

THPPC034

Design and Analysis of the PXIE CW Radio-frequency Quadrupole (RFQ)

rfq, cavity, controls, vacuum

3359

S.P. Virostek, M.D. Hoff, A.R. Lambert, D. Li, J.W. Staples
LBNL, Berkeley, California, USA
G.V. Romanov
Fermilab, Batavia, USA
C. Zhang
IAP, Frankfurt am Main, Germany

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The Project X Injector Experiment (PXIE) will be a prototype front end of the Project X accelerator proposed by Fermilab. PXIE will consist of an H⁻ ion source, a low-energy beam transport (LEBT), a radio-frequency quadrupole (RFQ) accelerator, a medium-energy beam transport (MEBT) and a section of superconducting cryomodules that will accelerate the beam from 30 keV to 30 MeV. LBNL has developed an RFQ design for PXIE with fabrication scheduled to begin before the end of CY 2012. The chosen baseline design is a four-vane, 4.4 m long CW RFQ with a resonant frequency at 162.5 MHz (2.4 wavelengths long). The RFQ will provide bunching and acceleration of a nominal 5 mA H⁻ beam to 2.1 MeV. The relatively low wall power density results in wall power losses that are less than 100 kW. The beam dynamics design has been optimized to allow for more than 99% beam capture with exceptionally low longitudinal emittance. The RFQ mechanical design and the results of RF and thermal analyses are presented here.

THPPD001

Stretched-wire Measurements of Small Bore Multipole Magnets

multipole, permanent-magnet, simulation, alignment

3500

G. Lebec, J. Chavanne, C. Penel
ESRF, Grenoble, France

Stretched-wire (SW) measurements of magnetic multipoles have been performed at radii ranging from 0.5 mm to 4 mm, with an accuracy of 10^-3 of the main multipole component. Theoretical aspects of SW measurements were investigated. The processing of the measured signals is based on a least square approach, instead of the Fourier transform widely used for rotating coil measurements. It allows correcting numerically the position errors of the SW and designing SW trajectory which are not sensitive to the main multipole, as with “bucked” rotating coils. This SW measurement bench was developed for the characterization of new ESRF magnets. It has been tested first with large aperture multipole magnets. An accuracy of 10^-4 has been obtained for a measurement radius of 30 mm. There is a demand in the magnetic measurement community for measuring small bore multipole magnets, with radius smaller than 5 mm. A small permanent magnet quadrupole was built in order to test the bench at small measurement radii.

THPPD007

ILSF Storage Ring Magnets

sextupole, dipole, multipole, power-supply

3506

S. Fatehi, R. Aslani, M.R. Khabbazi
IPM, Tehran, Iran

Iranian Light Source Facility (ILSF) is a 3 GeV storage ring consisting 32 combined bending magnets in 2 types, 10⁴ quadrupoles in 9 families and 128 sextupoles in 9 families. It was decided to use curved C-type, parallel ends, combined bending magnets that have the same lengths, a central fields of 1.42 T and total gap of 32 mm but quadrupole components of g1=-3.837 and g2=-5.839 T/m. Using two dimensional code POISSON and FEMM and applying appropriate shims, pole profile was optimized to maintain the field homogeneity over the full horizontal aperture of ±10, such that, field tolerance is of the order of 10^-4. Also a pole and yoke geometry was developed for the quadrupole, with a field gradient of 23 T/m, bore radius of 30.5 mm and magnetic length of 0.53m which is the maximum possible values in the lattice. Obtained field tolerance is of the order of 10^-4 in the good field region 18 mm. Sextupoles are supposed to have a bore radius of 34 mm, max sextupole component of 700 T/m2 and are designed in order to achieve a field tolerance of 10^-3 in the good field region of 12 mm. Also in order to investigate the end effects 3D calculations has been done by using Radia 3D code.

THPPD009

Accelerator Magnets R&D Programme at CERN

dipole, permanent-magnet, linac, luminosity

3512

D. Tommasini, L. Bottura, G. De Rijk, L. Rossi
CERN, Geneva, Switzerland

The exploitation and evolution of the CERN accelerator complex pose a continuous challenge for magnet engineers. Superconducting and resistive magnets have a comparable share. The overall mass of either is approximately 50,000 tons, spread over 3 major machines (PS, SPS and LHC), two large experimental area, and a number of smaller experiments and accelerator rings. On the short term (2012-2014) the CERN plan is to upgrade its injection chain (Linac4) and experimental area (HIE-Isolde, ELENA) that require mostly a multitude of resistive magnets. The medium-term plan for the evolution of the LHC complex (2015-2021), also referred to as High-Luminosity LHC, foresees interventions on about 1 km of the machine, with magnets to be substituted with higher field, larger aperture, or both. On the long term (2025-2035) we are exploring the technological challenges of very high field magnets, at the verge of 20 T for a High Energy LHC (HE-LHC), or extremely stable high gradient quadrupoles for the Compact Linear Collider (CLIC). In this paper we provide an overview of the R&D activities addressing the various lines of development, the technology milestones, and a broad time schedule.

THPPD010

Design, Assembly and First Measurements of a Short Model for CLIC Final Focus Hybrid Quadrupole QD0

multipole, magnet-design, lattice, permanent-magnet

3515

M. Modena, O. Dunkel, J.G. Perez, C. Petrone, P.A. Thonet, D. Tommasini
CERN, Geneva, Switzerland
E. Solodko, A.S. Vorozhtsov
JINR, Dubna, Moscow Region, Russia

In the framework of the Compact Linear Collider (CLIC) R&D, a tunable hybrid magnet design has been proposed for the final focus QD0 quadrupole. A short model of the magnet has been realized in order to validate the novel design and its expected performances. In order to achieve extremely high quadrupole gradients (>500 T/m), the magnet design combines: a core structure made in magnetic CoFe alloy “Permendur”, permanent magnet blocks, and air-cooled electromagnetic coils. Relevant aspects of this design are the wide tunability of the gradient range, the compactness and the absence of any vibrations. In this paper a reminder of the magnet design concept is given; then, the procurement and assembly main aspects are presented, followed by the results of the magnetic measurements. Finally, some manufacturing considerations relative to a full size magnet procurement are discussed.

THPPD015

Character and Performance of Magnets for the TPS Storage Ring

sextupole, multipole, dipole, storage-ring

3527

J.C. Jan, C.-H. Chang, H.-H. Chen, Y.L. Chu, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin, C.S. Yang, Y.T. Yu
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) is a third-generation light source. The orbit of the electron beam will be controlled with 48 dipoles, 240 quadrupoles, 168 sextupoles and several correctors in the storage ring. The construction of the first magnets for one sector, including prototype magnets, is to be completed during 2011 December. The mechanical dimensions of these magnets have been examined on a precise 3D-coordinate-measuring machine (CMM). The field strength, effective length and multipole errors were inspected with a rotating-coil measurement system (RCS) and a Hall-probe measurement system (HPS). The field center of the quadrupole and sextupole magnets is shimmed with a precise shimming block on the RCS bench. The inaccuracy of the position of the field center will be within 0.01 mm after shimming the feet. This work reports the current status, the construction performance, the mechanical shimming algorithm and the relative construction issue of the high precision magnet.

THPPD016

Construction and Measurement of Novel Adjustable Permanent Magnet Quadrupoles for CLIC

permanent-magnet, multipole, collider, linear-collider

3530

B.J.A. Shepherd, J.A. Clarke
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N.A. Collomb
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The CLIC drive beam decelerator requires 41,848 quadrupoles along its 42km length. In response to concerns over the heat load and operating costs of electromagnet systems, ASTeC in collaboration with CERN is developing adjustable permanent magnet-based quadrupoles. This novel design concept uses moving permanent magnets to adjust the quadrupole strength over a wide operating range. The design has focused not just on achieving the field strength and quality required but has also tried to make the design well suited to mass production, as the CLIC project requires 50 magnets to be completed every day for three years. Two permanent magnet quadrupole families have been designed, for the low and high energy ends of the decelerator respectively. We present the current status of the project, including construction and magnetic measurements of the first prototype.

THPPD018

Precision Magnet Measurements for X-band Accelerator Quadrupole Triplets

alignment, emittance, dipole, controls

3536

R.A. Marsh, S.G. Anderson, J.P. Armstrong
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. Beamline magnets will include an emittance compensation solenoid, windowpane steering dipoles, and quadrupole magnets. Demanding tolerances have been placed on the alignment of these magnets, which directly affects the electron bunch beam quality. A magnet mapping system has been established at LLNL in order to ensure the delivered magnets match their field specification, and the mountings are aligned and capable of reaching the specified alignment tolerances. The magnet measurement system will be described which uses a 3-axis Lakeshore gauss probe mounted on a 3-axis translation stage. Alignment accuracy and precision will be discussed, as well as centering measurements and analysis. The dependence on data analysis over direct multi-pole measurement allows a significant improvement in useful alignment information. Detailed analysis of measurements on the beamline quadrupoles will be discussed, including multi-pole content both from alignment of the magnets, and the intrinsic level of multi-pole magnetic field.

THPPD021

SC Magnet Development for SIS100 at FAIR

dipole, sextupole, multipole, cryogenics

3545

E.S. Fischer, A. Mierau, P. Schnizer
GSI, Darmstadt, Germany

Superconducting magnets have been constructed and tested for the SIS100 (Heavy Ion Synchrotron with a beam rigidity of 100 Tm) of the FAIR project. The requested high quality of the magnetic field as well as the fast periodic ramp of the SIS100 (2T, 1Hz) requires that any source of AC losses is tightly reduced by carefully optimising the 3D geometry of the yoke, choosing the appropriate iron material and minimising the eddy current loops. In addition optimal wire, cable and coil designs have been developed. The residual heat production will be reliable removed by an efficient cooling scheme. The beam pipe vacuum chamber must operate stably as a cryo-pump with surface temperatures below 20K. The electromagnetic, thermal and mechanical aspects were optimised and finally investigated based on physical analysis, supported by FEM calculations and dedicated tests. The results obtained on the main magnets were used for dedicated development of the corrector magnets and their effective integration in the complete cryo-magnet complex of the accelerator. We describe the features of the final magnets next to their optimised fields and present the construction status of the SIS100 magnets.

THPPD023

Solenoid Field Calculation of the SuperKEKB Interaction Region

solenoid, interaction-region, superconducting-magnet, optics

3548

N. Ohuchi, Y. Arimoto, M. Iwasaki, H. Koiso, A. Morita, Y. Ohnishi, K. Oide, M. Tawada, K. Tsuchiya, H. Yamaoka
KEK, Ibaraki, Japan

The SuperKEKB is the electron-positron collider, and the target luminosity is 8×10³⁵ cm^-2s⁻¹, which is 40 times larger than the attained luminosity of KEKB. The beam final focus system consists of many types of superconducting magnets as 8 quadrupoles, 40 correctors and 4 compensation solenoids. These focusing magnets and correctors are designed to be operated inside the particle detector, Belle, and under the solenoid field of 1.5 T. From the analysis of beam optics, the solenoid field profile has serious impact on the beam vertical emittance. We designs the solenoid field profile along the Belle axis in a 2-dimensional model as the first step, and now we developed this model to the 3-dimensional calculation in detail. The solenoid field profiles along the both beam lines are generated with the combine solenoid field by the Belle solenoid and the compensation solenoids, and the magnetic components of the magnets and the magnetic shields on the beam lines. The model is very complicate. From the calculation results, we will discuss the influence on the beam optics and the final focusing magnet system.

THPPD025

Expected and Measured Behaviour of the Tune in the LHC Operation at 3.5 TeV

injection, dipole, feedback, betatron

3554

N. Aquilina
CERN, Geneva, Switzerland

The tune of the Large Hadron Collider depends on the strength of the quadrupole magnets, the b2 component in the main dipoles plus the b3 component in the main dipoles and the sextupolar correctors via feed down in case of systematic misalignment. The magnetic model of the machine, based on a fit of magnetic measurements, has an intrinsic precision which can be estimated in a few units. During the first years of operation of the LHC, tune has been routinely measured and corrected through a feedback system. In this paper we reconstruct from the beam measurements and the settings of the feedback loop the evolution of tune during injection, ramp, and squeeze. This gives the obtained precision of the magnetic model of the machine with respect to quadrupolar and sextupolar components. At the injection plateau there is an unexpected large decay whose origin is not understood: we present the data, with the time constants and the dependence on the previous cycles, and compare to the magnetic measurements. During the ramp the tune drifts by about 0.05: this precision is related to the precision in tracking the quadrupolar field in the machine.

THPPD027

Consolidation of the 13 kA Splices in the Electrical Feedboxes of the LHC

dipole, controls, cryogenics, superconducting-magnet

3560

A. Perin, S. Atieh, O. Pirotte, R. Principe, D. Ramos, F. Savary, C.E. Scheuerlein, J.Ph. G. L. Tock, A.P. Verweij
CERN, Geneva, Switzerland

In 2008 a defective connection in one of the 13 kA dipole circuits of the LHC caused an electric breakdown that resulted in extensive damage in a sector of the accelerator. The investigation performed after the accident showed the necessity to consolidate the electrical splices of the 13 kA dipole and quadrupole circuits in order to operate the LHC at its nominal energy of 7 TeV. These circuits are powered through electrical feedboxes located at each end of the 8 sectors of LHC. In the feedboxes the current is routed from room temperature to the superconducting magnets along current leads and superconducting busbars and flows through at least two internal splices. These splices are based on the same technologies as the magnet to magnet ones but they are significantly different in terms of environment and configuration. As for the magnet to magnet splices, a consolidation will be necessary to operate them at nominal current. This paper presents an analysis of the properties of these splices and the technologies that will be used to consolidate them. The quality control provisions and the workflow to perform this operation during the first long shutdown of LHC are also presented.

THPPD030

Characterization of a Measurement System for Dynamic Effects in Large-aperture SC Quadrupole Magnets

multipole, superconducting-magnet, insertion, controls

3569

S. Russenschuck, M. Bajko, M.C.L. Buzio, G. Deferne, O. Dunkel, L. Fiscarelli, D. Giloteaux, L. Walckiers
CERN, Geneva, Switzerland

A new measurement system, based on a large-diameter search-coil rotating in the superfluid helium, a fast digital integrator, a motor drive unit with sliprings, and a flexible software environment was devolped at CERN for the measurement of dynamic effects in superconducting magnets*. This system has made it possible the measure, with a resolution of up to 8 Hz, the multipole field errors due to superconductor magnetization and interstrand coupling currents. In the paper we will present the development and calibration of the measurement system, its installation in the vertical cryostat of CERN's recently refurbished test station, and its application to the US-LARP** built, 120-mm-aperture Nb3Sn quadrupole magnet (HQ) for the upgrade of the LHC insertion regions.
* P. Arpaia et al. Active Comp. of Field Errors within ± 2 PPM in SC Magnets, NIM A, 2011
** H. Felice et al. Design of HQ, a High Field Large Bore Nb3Sn Quad. Magnet for LARP, IEEE TAS, 2009

THPPD031

Measurement of the Residual Resistivity Ratio of the Bus Bars Copper Stabilizer of the 13 kA Circuits of the LHC

dipole, instrumentation, simulation, factory

3572

A. Apollonio, S.D. Claudet, M. Koratzinos, R. Schmidt, A.P. Siemko, M. Solfaroli Camillocci, J. Steckert, H. Thiesen, A.P. Verweij
CERN, Geneva, Switzerland

After the incident of September 2008, the operational beam energy of the LHC has been set to 3.5 TeV, since not all joints of the superconducting busbars between magnets have the required quality for 7 TeV operation. This choice is based on simulations to determine the safe current in the main dipole and quadrupole magnets, reproducing the thermal behavior of a quenched superconducting joint by taking into account all relevant factors that affect a possible thermal runaway. One important parameter of the simulation is the RRR (Residual Resistivity Ratio) of the copper stabilizer of the busbar connecting superconducting magnets. A dedicated campaign to measure this quantity for the main 13kA circuits of the LHC on all sectors was performed during the Christmas stop in December 2010 and January 2011. The measurement method as well as the data analysis and results are presented in this paper.

THPPD032

Consolidation of the LHC Superconducting Circuits: A Major Step towards 14 TeV Collisions

dipole, superconducting-magnet, controls, vacuum

3575

J.Ph. G. L. Tock, F.F. Bertinelli, F. Bordry, P. Fessia, R. Ostojic, A. Perin, H. Prin, F. Savary, C.E. Scheuerlein, H.H.J. Ten Kate, A.P. Verweij, G.P. Willering
CERN, Geneva, Switzerland

Following the incident in one of the main dipole circuits of the Large Hadron Collider (LHC) in September 2008, a detailed analysis of all magnet circuits has been performed by a dedicated task force. This analysis has revealed several critical issues in the design of the 13 kA splices between the main LHC cryomagnets. These splices have to be consolidated before increasing the beam energy above 4 TeV and to operate the LHC close to 7 TeV per beam. The design for the consolidated 13 kA splices is now complete and has been reviewed by an international committee of experts. In the process, all types of superconducting circuits have been thoroughly screened and several important recommendations were established. They were critically assessed and the resulting actions are presented. In addition to the work on the 13 kA splices, other interventions will be performed during the first long shut-down of the LHC to consolidate globally all the superconducting circuits. The associated quality controls have been defined and are detailed in the operations workflow. The schedule constraints, repairs production rate, available space and resources are presented as well.

THPPD034

Quench Performance and Field Quality of 90-mm Nb3Sn Quadrupoles of TQC Series

dipole, collider, controls, alignment

3581

G. Chlachidze, N. Andreev, R. Bossert, J. DiMarco, V. Kashikhin, M.J. Lamm, A. Nobrega, I. Novitski, M.A. Tartaglia, G. Velev, A.V. Zlobin
Fermilab, Batavia, USA

Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
A series of accelerator quality Nb3Sn quadrupole models has been developed, fabricated and tested at Fermilab. The magnet design includes a 90 mm aperture surrounded by four two-layer Nb3Sn coils supported by a stainless steel collar, iron yoke and stainless steel skin. This paper describes the design and fabrication features of the quadrupole models and presents the summary of model tests including quench performance and field quality at 4.5 and 1.9 K.

THPPD035

Magnets for Interaction Regions of a 1.5×1.5 TeV Muon Collider

dipole, collider, background, luminosity

3584

V. Kashikhin, Y. Alexahin, N.V. Mokhov, A.V. Zlobin
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
The updated IR optics and conceptual designs of large aperture superconducting quadrupole magnets for a muon collider with a c.o.m. energy of 3 TeV and an average luminosity of 4·10³⁴ cm^-2 s^-1 are presented. All magnets are based on the Nb3Sn superconductor and designed to provide an adequate operation field gradient in the given aperture with the critical current margin required for reliable machine operation. Special dipole coils were added to quadrupole designs to provide ~2 T bending field and thus facilitate chromaticity correction and dilute decay electron fluxes on the detector. Magnet cross-sections were optimized to achieve the best possible field quality in the magnet aperture occupied with beams. Magnet parameters are reported and compared with the requirements. Energy deposition calculations with the MARS code have allowed to optimize parameters of inner absorbers, collimators in interconnect regions and Machine-Detector Interface.

THPPD036

High-Field Combined-Function Magnets for a 1.5×1.5 TeV Muon Collider Storage Ring

dipole, collider, magnet-design, lattice

3587

V. Kashikhin, Y. Alexahin, N.V. Mokhov, A.V. Zlobin
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
A new storage ring lattice based on combined function high-field magnets and conceptual designs of superconducting magnets with dipole and quadrupole coils for a muon collider with a c.o.m. energy of 3 TeV and an average luminosity of 4x10³⁴ cm^-2 s^-1 are presented. Magnets are designed to provide the required focusing field gradient and bending field in the aperture with the appropriate operation margin. Magnets have large apertures to provide an adequate space for internal absorbers, vacuum insulation, beam pipe, and helium channel. Coil cross-sections were optimized to achieve the best possible field quality in the magnet aperture occupied with beams. Magnet parameters are reported and compared with the requirements. Energy deposition calculations with the MARS code have allowed to optimize parameters of inner absorbers and collimators in interconnect regions, thus reducing peak power density and dynamic loads to the tolerable levels.

THPPD037

Design Studies of a Dipole with Elliptical Aperture for the Muon Collider Storage Ring

dipole, collider, storage-ring, electron

3590

M.L. Lopes, V. Kashikhin, J.C. Tompkins, A.V. Zlobin
Fermilab, Batavia, USA
R.B. Palmer
BNL, Upton, Long Island, New York, USA

Funding: Work supported partially by US-MAP and by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
The requirements and operating conditions for superconducting magnets used in a Muon Collider Storage Ring are challenging. About one third of the beam energy is deposited along the magnets by the decay electrons. As a possible solution an elliptical tungsten absorber could intercept the decay electrons and absorb the heat limiting the heat load on superconducting coils to the acceptable level. In this paper we describe the main design issues of dipoles with an elliptical aperture taking into consideration the field and field quality. The temperature margin and the forces in the coils are presented as well.

THPPD038

Measurements of the Persistent Current Decay and Snapback Effect in Nb3Sn Accelerator Prototype Magnets at Fermilab

dipole, injection, sextupole, multipole

3593

G. Velev, G. Chlachidze, J. DiMarco, V. Kashikhin
Fermilab, Batavia, USA

In recent years, Fermilab has been performing an intensive R&D program on Nb3Sn accelerator magnets. This program has included dipole and quadrupole magnets for different programs and projects, including LARP and VLHC. A systematic study of the persistent current decay and snapback effect in the fields of these magnets was executed at the Fermilab Magnet Test Facility. The decay and snapback were measured under a range of conditions including variations of the current ramp parameters and flattop and injection plateau durations. This study has mostly focused on the dynamic behavior of the normal sextupole and dodecapole components in dipole and quadrupole magnets respectively. The paper summarizes the recent measurements and presents a comparison with previously measured NbTi magnets.

THPPD040

Quench Protection Analysis of a Single-Aperture 11T Nb3Sn Demonstrator Dipole for LHC Upgrades

dipole, simulation, luminosity, status

3599

A.V. Zlobin, I. Novitski, R. Yamada
Fermilab, Batavia, USA

Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
The planned upgrade of the LHC collimation system foresees additional collimators to be installed in the dispersion suppressor areas around points 2, 3, and 7. The necessary longitudinal space for the collimators could be provided by replacing some 8.33-T 15-m-long NbTi LHC main dipoles with shorter 11-T Nb3Sn dipoles compatible with the LHC lattice and main systems. To demonstrate this possibility, in 2011 Fermilab and CERN started a joint R&D program with the goal of building by 2014 a 5.5-m-long twin-aperture dipole prototype suitable for installation in the LHC. The first step of this program is the development of a 2-m-long single-aperture demonstration dipole with the nominal field of 11 T at the LHC nominal current of ~11.85 kA and 60-mm bore with ~20% margin. This paper summarizes the results of quench protection analysis of the single-aperture Nb3Sn demonstrator dipole for the LHC collimation system upgrade.

THPPD042

High Radiation Environment Nuclear Fragment Separator Dipole Magnet

dipole, radiation, magnet-design, target

3605

S.A. Kahn
Muons, Inc, Batavia, USA
R.C. Gupta
BNL, Upton, Long Island, New York, USA

Funding: Supported in part by STTR Grant 4746 · 11SC06273
Magnets in the fragment separator region of the Facility for Rare Isotope Beams (FRIB) would be subjected to extremely high radiation and heat loads. Critical elements of FRIB are the dipole magnets which select the desired isotopes. Since conventional NiTi and Nb3Sn superconductors must operate at ~4.5 K, the removal of the high heat load generated in these magnets with these superconductors would be difficult. The coils for these magnets must accommodate the large curvature from the 30° bend that the magnets subtend. High temperature superconductor (HTS) have been shown to be radiation resistant and can operate in the 20-50 K temperature range where heat removal is an order of magnitude more efficient than at 4.5 K. Furthermore these dipole magnets must be removable remotely for servicing because of the extremely high radiation environment. This paper will describe the magnetic and conceptual design of these magnets.

THPPD043

Radiation-tolerant Multipole Correction Coils for FRIB

octupole, radiation, sextupole, multipole

3608

S.A. Kahn
Muons, Inc, Batavia, USA
R.C. Gupta
BNL, Upton, Long Island, New York, USA

Multipole correction insert coils with significant field strength are required inside the large aperture superconducting quadrupole magnets in the fragment separator section of the Facility for Rare Isotope Beams (FRIB). Correction coils made with copper do not create the required field and conventional low temperature superconductors are not practical in the fragment separator magnets which will operate at 40-50 K. The correction coils should be made of HTS as the main quadrupole coils are. There is a significant advantage to using HTS in these coils as it can withstand the high radiation and heat load that will be present. This paper will describe an innovative design suitable for coils with the complex end geometry of cylindrical coils. We will look at the forces on the corrector coils from the mail quadrupole fields and anticipate possible coil distortions.

THPPD044

Fabrication and Testing of Curved Test Coil for FRIB Fragment Separator Dipole

dipole, radiation, FEL, proton

3611

S.A. Kahn
Muons, Inc, Batavia, USA
J. Escallier, R.C. Gupta, G. Jochen, Y. Shiroyanagi
BNL, Upton, Long Island, New York, USA

Funding: Supported in part by SBIR Grant 4746 · 11SC06273
A critical element of the fragment separator region of the Facility for Rare Isotope Beams (FRIB) is the 30° dipole bend magnet. Because this magnet will be subjected to extremely high radiation and heat loads, operation at 4.5 K would not be possible. High temperature superconductors which have been shown to be radiation resistant and can operated in the 30-50 K temperature range which is more effective for heat removal. An efficient design for this magnet would make use of coils that follow the curvature of the magnet. Winding curved coils with negative curvature are difficult as the coil tends to unwind during the process. As part of an R&D effort for this magnet we are winding a ¼ scale test coil for this magnet with YBCO conductor and are testing it at 77 K. This paper will discuss the winding process and the test results of this study.

THPPD054

Low Current Bipolar Magnet Power Supply System at the PLS-II Storage Ring

dipole, lattice, EPICS, power-supply

3635

S.-C. Kim, J.Y. Huang, K.R. Kim, S.H. Nam, S. Shin, Y.G. Son, C.W. Sung
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: * This work is supported by the Ministry of Education, Science and Technology, Korea.
Lattice of the Storage Ring (SR) is changed from TDB to DBA, and beam energy is enhanced from 2.5 GeV to 3.0 GeV at the Pohang Light Source upgrade (PLS-II). At the PLS-II, Magnet Power Supplies (MPS) were newly designed according to magnet specification of the PLS-II. All MPSs are adopted switching type power conversion technology. Low current bipolar MPSs for vertical corrector(VC), horizontal corrector(HC), fast corrector(FC), aux.-quadrupole(AQ), skew(SK) and dipole trim coil(TR) magnets are H-bridge type. All MPSs are performed less than ± 10 ppm output current stability and adopted full digital controller. Except vertical corrector MPSs, all unipolar and bipolar MPSs are developed as embedded EPICS IOC. In this paper, we report on the development and characteristics of the bipolar MPS for the PLS-II Storage Ring.

THPPD055

High Current Unipolar Magnet Power Supply System at the PLS-II Storage Ring

power-supply, sextupole, lattice, septum

3638

S.-C. Kim, J.Y. Huang, K.R. Kim, S.H. Nam, S. Shin, Y.G. Son, C.W. Sung
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This work is supported by the Ministry of Education, Science and Technology, Korea.
Lattice of the Storage Ring (SR) is changed from TDB to DBA, and beam energy is enhanced from 2.5 GeV to 3.0 GeV at the Pohang Light Source upgrade (PLS-II). At the PLS-II, Magnet Power Supplies (MPS) were newly designed according to magnet specification of the PLS-II. All MPSs are adopted switching type power conversion technology. High current unipolar MPSs for bending(BD), main-quadrupole(MQ), sextupole(ST) and septum(SP) magnet are parallel operation type of unit stack buck type power supply. Unit stack of unipolar MPS has capability maximum 250A and operation 10kHz. BD and MQ MPS are adopted four stack as each stack 90degree phase shift switching, and have capability maximum 1000 A. ST MPS is adopted two stack as each stack 180degree phase shift switching, and have capability maximum 500 A. SP MPS is adopted single, and have capability maximum 250 A. All unipolar MPSs are developed as full digital controller, embedded EPICS IOC and operated less than ± 10ppm current stability. In this paper, we report on the development and characteristics of the high current unipolar MPS for the PLS-II SR.

THPPD066

High Precision Programmable of TPS Quadrupole Magnet Power Supply

controls, power-supply, synchrotron, feedback

3662

Y.S. Wong, J.C. Huang, K.-B. Liu, W.S. Wen
NSRRC, Hsinchu, Taiwan

In 1993, the first of Taiwan light source was held on October 16. First beam stored in the storage ring and facility at synchrotron radiation research centre (SRRC) was opened to users and the full energy injection to 1.5Gev after seven years. In 2007, the president of Executive Yuan Taiwan had been announcement to set up a third-generation synchrotron radiation. Taiwan Photon Source (TPS) project total budget of NT6, 885 million from 2007~ 2013. TPS project will improve technical capability to build to3.3Gev electron energy. Totally had been installed 1032sets of magnet power supplies for the storage ring and 152 sets for the injector. In the future, Taiwan photon source set up complete and operation, it will offer one of the world's brightest synchrotron x-ray sources.

THPPP019

Tune Determination of Strongly Coupled Betatron Oscillations in a Fast Ramping Synchrotron

coupling, booster, damping, betatron

3770

Y. Alexahin, E. Gianfelice-Wendt, W.L. Marsh, A.K. Triplett
Fermilab, Batavia, USA

Funding: Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Tune identification - i.e. attribution of the spectral peak to a particular normal mode of oscillations - can present a significant difficulty in the presence of strong transverse coupling when the normal mode with a lower damping rate dominates spectra of Turn-by-Turn oscillations in both planes. The introduced earlier phased sum algorithm* helped to recover the weaker normal mode signal from the noise, but by itself proved to be insufficient for automatic peak identification in the case of close phase advance distribution in both planes. To resolve this difficulty we modified the algorithm by taking and analyzing Turn-by-Turn data for two different ramps with the beam oscillation excited in each plane in turn. Comparison of the relative amplitudes of Fourier components allows for automatic correct tune identiﬁcation. The proposed algorithm was implemented in the Fermilab Booster B38 console application and successfully used in tune, coupling and chromaticity measurements.
* Y. Alexahin, E. Gianfelice-Wendt, W. Marsh, Proc. IPAC10, Kyoto, May 2010, p. 1179.

THPPP029

Simultaneous Global Coupling and Vertical Dispersion Correction in RHIC

coupling, proton, polarization, heavy-ion

3794

C. Liu, Y. Luo, M.G. Minty
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.
Residual vertical dispersion on the order of ±0.2 m (peak to peak) has been measured at store energies for both polarized proton and heavy ion beams. The hypothesis is that this may have impact on the polarization transmission efficiency during the energy ramp, the beam lifetimes, and, especially for heavy ions, the dynamics aperture. An algorithm to correct global coupling and dispersion simultaneously using skew quads was developed for RHIC. Simulation results together with the measured coupling and dispersion functions before and after correction will be shown for both injection and store together with an assessment of overall collider performance improvement.

THPPP042

The First Step of RFQ Development in KBSI

rfq, ion, emittance, dipole

3829

J.W. Ok, S. Choi, B.C. Kim, B.S. Lee, J.Y. Park, M. Won, J.H. Yoon
Korea Basic Science Institute, Busan, Republic of Korea

The RFQ for accelerating an ion beam is being developed in Korea Basic Science Institute (KBSI). The KBSI RFQ is designed to accelerate 1 mA lithium beam (Q/A=3/7) at 88 MHz. It is considered to be a 4-vane RFQ structure. The injection beam energy into RFQ is 12 keV/u, the output beam energy downstream from RFQ is 300 keV/u. The RFQ has to show stable operation, meet availability, and have the minimum losses so as to guarantee the best performance/cost ratio. At the first step, two dimensional geometry structure was studied using SUPERFISH code for the resonance frequency of quadrupole and dipole modes. Three dimensional field distributions were investigated by CST microwave studio. The beam dynamics in RFQ accelerator were studied using PARMTEQM code. Based on these results, the structural analysis should be studied and a cold model will be fabricated and investigated. The practical KBSI RFQ will be manufactured in next year.

THPPP052

Modelling the ISIS 70 MeV Linac

DTL, linac, rfq, simulation

3859

D.C. Plostinar, C.R. Prior, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
A.W. Mitchell
University of Warwick, Coventry, United Kingdom

The ISIS linac consists of four DTL tanks that accelerate a 50 pps, 20 mA H⁻ beam up to 70 MeV before injecting it into an 800 MeV synchrotron. Over the last decades, the linac has proved to be a stable and reliable injector for ISIS, which is a significant achievement considering that two of the tanks are nearly 60 years old. At the time the machine was designed, the limited computing power available and the absence of modern modeling codes, made the creation of a complex simulation model almost impossible. However, over the last few years, computer tools have became an integral part of any accelerator design, so in this paper we present a beam dynamics model of the ISIS linac. A comparison between the simulation results and machine operation data will be discussed, as well as possible linac tuning scenarios and recommended upgrades based on the new model.

THPPP056

Beam Loss Due to Misalignments, RF Jitter and Mismatch in the Fermilab Project-X 3GeV CW Linac

linac, solenoid, lattice, beam-losses

3868

J.-P. Carneiro, V.A. Lebedev, S. Nagaitsev, J.-F. Ostiguy, A. Saini, B.G. Shteynas, N. Solyak
Fermilab, Batavia, USA

This paper presents an analysis of beam losses along the current design of the FNAL 3 GeV superconducting cw linac. Simulations from the RFQ exit up to the end of the linac (~430 meters) are performed on the FermiGrid using the beam dynamics code TRACK. The impact of beam mismatch, element misalignments, and RF jitter on the beam dynamics is discussed and corresponding beam loss patterns are presented. A correction scheme to compensate for misalignments is described.

THPPP064

Project X RFQ EM Design

rfq, simulation, dipole, radio-frequency

3883

G.V. Romanov
Fermilab, Batavia, USA
M.D. Hoff, D. Li, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA

Project X is a proposed multi-MW proton facility at Fermi National Accelerator Laboratory (FNAL). The Project X front-end would consist of an H⁻ ion source, a low-energy beam transport (LEBT), a cw 162.5 MHz radio-frequency quadrupole (RFQ) accelerator, and a medium-energy beam transport (MEBT). Lawrence Berkeley National Laboratory (LBNL) and FNAL collaboration is currently developing the designs for various components in the Project X front end. This paper reports the detailed EM design of the cw 162.5 MHz RFQ that provides bunching of the 1-10 mA H⁻ beam with acceleration from 30 keV to 2.1 MeV.

THPPP081

Status of Injection Energy Upgrade for J-PARC RCS

power-supply, injection, impedance, kicker

3921

N. Hayashi, H. Harada, H. Hotchi, J. Kamiya, P.K. Saha, Y. Shobuda, T. Takayanagi, N. Tani, M. Watanabe, Y. Watanabe, K. Yamamoto, M. Yamamoto, Y. Yamazaki, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
T. Toyama
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The injection energy upgrade for J-PARC RCS is planed in 2013. This includes the power supplies upgrade of injection pulsed magnet system, suppression for leakage field, quadrupole correction magnets, reduction of kicker impedance effect and improvements of beam diagnostic instrumentation. The paper reports the present status.

THPPP085

End to End Beam Dynamics of the ESS Linac

linac, proton, target, DTL

3933

M. Eshraqi, H. Danared, A. Ponton
ESS, Lund, Sweden
I. Bustinduy
ESS Bilbao, Bilbao, Spain
L. Celona
INFN/LNS, Catania, Italy
M. Comunian
INFN/LNL, Legnaro (PD), Italy
A.I.S. Holm, S.P. Møller, H.D. Thomsen
ISA, Aarhus, Denmark
J. Stovall
CERN, Geneva, Switzerland

The European Spallation Source, ESS, uses a linear accelerator to deliver a high intensity proton beam to the target station. The nominal beam power on target will be 5~MW at an energy of 2.5~GeV. We briefly describe the individual accelerating structures and transport lines through which we have carried out multiparticle beam dynamics simulations. We will present a review of the beam dynamics from the source to the target.

THPPP086

UFOs in the LHC: Observations, Studies and Extrapolations

simulation, beam-losses, proton, diagnostics

3936

T. Baer, M.J. Barnes, F. Cerutti, A. Ferrari, N. Garrel, B. Goddard, E.B. Holzer, S. Jackson, A. Lechner, V. Mertens, M. Misiowiec, E. Nebot Del Busto, A. Nordt, J.A. Uythoven, V. Vlachoudis, J. Wenninger, C. Zamantzas, F. Zimmermann
CERN, Geneva, Switzerland
T. Baer
University of Hamburg, Hamburg, Germany
N. Fuster Martinez
Valencia University, Atomic Molecular and Nuclear Physics Department, Valencia, Spain

Unidentified falling objects (UFOs) are potentially a major luminosity limitation for nominal LHC operation. They are presumably micrometer sized dust particles which lead to fast beam losses when they interact with the beam. With large-scale increases and optimizations of the beam loss monitor (BLM) thresholds, their impact on LHC availability was mitigated from mid 2011 onwards. For higher beam energy and lower magnet quench limits, the problem is expected to be considerably worse, though. In 2011/12, the diagnostics for UFO events were significantly improved: dedicated experiments and measurements in the LHC and in the laboratory were made and complemented by FLUKA simulations and theoretical studies. The state of knowledge, extrapolations for nominal LHC operation and mitigation strategies are presented.

THPPR002

The Undulator Control System for the European XFEL

undulator, controls, photon, electron

3966

S. Karabekyan, A. Beckmann, J. Pflüger
European XFEL GmbH, Hamburg, Germany
N. Burandt, J. Kuhn
Beckhoff Automation GmbH, Verl, Germany
A. Schöps
DESY, Hamburg, Germany

The European XFEL project is a 4th generation light source. The first beam will be delivered in the beginning of 2015 and will produce spatially coherent ≤80fs short photon pulses with a peak brilliance of 10³²–10³⁴ photons/s/mm²/mrad²/0.1% BW in the energy range from 0.26 to 29 keV at electron beam energies of 10.5 GeV, 14 GeV, or 17.5 GeV . The Undulator systems are used to produce photon beams for SASE 1, SASE 2 and SASE 3. Each undulator system consists of an array of undulator cells installed in a row along the electron beam. A single undulator cell itself consists of a planar undulator, a phase shifter, magnetic field correction coils and a quadrupole mover. This paper describes the design of the entire undulator control system including local and global control. It presents a concept of integration of the undulator control into the accelerator control system as well as into the experiment control.

THPPR013

Beam Transport in Alternative Lattices at the University of Maryland Electron Ring (UMER)

lattice, injection, focusing, betatron

3993

S. Bernal, B.L. Beaudoin, M. Cornacchia, R.A. Kishek, D.F. Sutter
UMD, College Park, Maryland, USA

Funding: This work is funded by the US Dept. of Energy Offices of High Energy Physics and High Energy Density Physics, and by the US Dept. of Defense Office of Naval Research and Joint Technology Office.
We discuss the motivation, general procedure and results of first experiments of beam transport with two alternative focusing schemes at UMER, a low-energy (10 keV), high-current (1-100 mA) electron storage ring. The new ring optics simplifies injection and RMS envelope matching, and gives us a larger number of beam position monitors (BPMs) per (un-depressed) betatron wavelength, all of which are desirable conditions for better orbit control. Furthermore, one of the new optics schemes is more symmetrical than the standard one, facilitating e.g. the implementation of quadrupole scans for betatron resonance studies. The alternative lattices also allow us to expand significantly on the tune parameter space available for the study of space-charge dominated beam transport.

THPPR036

Quench Limit Calculations for Steady State Heat Deposits in LHC Inner Triplet Magnets

proton, luminosity, insertion, simulation

4050

D. Bocian
IFJ-PAN, Kraków, Poland
F. Cerutti, B. Dehning, A.P. Siemko
CERN, Geneva, Switzerland

In hadron colliders such as the LHC, the energy deposited in the superconductors by the particles lost from the beams or coming from the collision debris may provoke quenches detrimental to the accelerator operation. A Network Model is used to simulate the thermodynamic behavior of the superconducting magnets. In previous papers the validations of network model with measurements performed in the CERN and Fermilab magnet test facilities were presented. This model was subsequently used for thermal analysis of the current LHC inner triplet quadrupole magnets for beam energy of 3.5 TeV and 7 TeV. The detailed study of helium cooling channels efficiency for energy deposits simulated with FLUKA is presented. Some conclusions are drawn on expected inner triplet magnets quench limit.

THPPR038

Failure Studies at the Compact Linear Collider: Main Linac and Beam Delivery System

linac, betatron, wakefield, extraction

4056

C.O. Maidana, M. Jonker, A. Latina
CERN, Geneva, Switzerland

The proposed Compact Linear Collider (CLIC) is based on a two-beam acceleration scheme. The energy of two high-intensity, low-energy drive beams is extracted and transferred to two low-intensity, high-energy main beams. The machine protection and electrical integrity group has the mission to protect the various machine components from damage caused by ill controlled beams. Various failure scenarios were studied and the potential damage these failures could cause to the machine structures were estimated. In this paper, first results of the beam response to correctors and/or quadrupole kick failures in the main linac and in the beam delivery system (BDS) sections are presented as well as possible collimator damage scenarios. The use of the code PLACET for machine protection analysis is described as well.

THPPR052

The MedAustron Proton Gantry

optics, dipole, proton, synchrotron

4091

A. Koschik
PSI, Villigen, Switzerland
U. Dorda, A. Koschik
EBG MedAustron, Wr. Neustadt, Austria
D. Meer, E.S. Pedroni
Paul Scherrer Institut, Villigen, Switzerland

The MedAustron project realizes a synchrotron based accelerator facility in Austria for cancer treatment with protons and carbon ions, currently in the construction phase. In order to allow full patient treatment flexibility, one of the four treatment rooms will be equipped with a proton gantry. While its hardware design is a copy of the PSI Gantry 2, different constraints on the beam optics must be accounted for as MedAustron uses a synchrotron as particle accelerator and a rotator to match the beam into the rotated frame, as compared to the cyclotron of the PSI PROSCAN facility. This paper presents the current status of the hardware design and procurement and a review of the design characteristics of the PSI Gantry 2 for the MedAustron case. In particular the stability of the beam parameters during beam scanning over the treatment scan area is investigated in detail. To achieve utmost parallel active scanning performance, the magnet design parameters (edge angles, corrector quadrupole, tapered dipole) have been optimized for PSI Gantry 2. Equivalent studies are undertaken for the MedAustron requirements and constraints in this paper.

THPPR075

The UK MEIS Facility : A New Future

ion, scattering, target, alignment

4151

R.J. Barlow
University of Huddersfield, Huddersfield, United Kingdom

The Medium Energy Ion Scattering facility at the Daresbury Laboratory, one of only ~10 such facilities in the world, has served the UK community since 1996. It provides a 50-400 keV ion beam and a very comprehensive experimental station where samples can be studied and the energies and angles of the recoil ions measured. It is now closing, but will be be relocated some 50 miles to the University of Huddersfield: it should be recommissioned and available to users in early 2012. We will report on progress, and on the facilities which will be available for users at the new site and under the new management.