IPAC2012 - List of Keywords (collider)

Paper	Title	Other Keywords	Page
MOEPPB001	RF-breakdown Kicks at the CTF3 Two-beam Test Stand	linac, extraction, linear-collider, acceleration	73
	A. Palaia, M. Jacewicz, T. Muranaka, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Farabolini CEA/DSM/IRFU, France
	The measurement of the effects of RF-breakdown on the beam in CLIC prototype accelerator structures is one of the key aspects of the CLIC two-beam acceleration scheme being addressed at the Two-beam Test Stand (TBTS) at CTF3. RF-breakdown can randomly cause energy loss and transverse kicks to the beam. Transverse kicks have been measured by means of a screen intercepting the beam after the accelerator structure. In correspondence of a RF-breakdown we detect a double beam spot which we interpret as a sudden change of the beam trajectory within a single beam pulse. To time-resolve such effect, the TBTS has been equipped with five inductive Beam Position Monitors (BPMs) and a spectrometer line to measure both relative changes of the beam trajectory and energy losses. Here we discuss the methodology used and we present the latest results of such measurements.

MOEPPB006	Formation of Beams in the Ion Accelerator Complex of the Medium Energy Electron Ion Collider Facility at JLab	ion, booster, proton, acceleration	88
	S.L. Manikonda, P.N. Ostroumov ANL, Argonne, USA B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. At the interaction point of the Medium Energy Electron Ion Collider (MEIC) facility the luminosity of 10³³cm^-2s^-1 will be achieved through the collision of counter rotating beams of 0.5A ions and 3A electrons at 750MHz frequency. Formation of ion beams at MEIC is carried out in the Ion Accelerator Complex (IAC) comprising of a linac, pre-booster ring, booster ring, and a collider ring. We will describe the scheme proposed for the formation of ion beams at MEIC facility from the point of view of longitudinal beam dynamics. The proposed scheme minimizes losses due to space charge effects at low energies and needs moderate RF requirements already achieved at other existing facilities. Simulation studies have been conducted to verify the proposed scheme. We will present the results of these simulation studies.

MOEPPB008	Simulation of Hollow Electron Beam Collimation in the Fermilab Tevatron Collider	electron, simulation, collimation, quadrupole	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.

MOPPC016	Combined Ramp and Squeeze at the Large Hadron Collider	optics, injection, quadrupole, 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.

MOPPC034	Use of Helical Transport Channels for Bunch Recombination	simulation, luminosity, emittance, focusing	205
	D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA C.M. Ankenbrandt, C. Y. Yoshikawa Muons, Inc, Batavia, USA
	Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this paper we describe a new method for bunch recombination. We combine the high-chronicity of a helical transport channel (HTC) with the high-frequency bunching and phase-energy rotation concept (time-reversed) to obtain a compact bunch recombination system adapted to a muon collider scenario. We first present an idealized 1-D system with multiple chronicity transports. We then implement the concept in a single-chronicity channel, obtaining bunch recombination of 13 200MHz-spaced bunches to a single collider-ready bunch within a compact transport with modest rf requirements. That example is demonstrated within G4BL 3-D simulations. Variations and adaptations for different recombination requirements are discussed.

MOPPC037	Muon Collider Detector Backgrounds	background, electron, simulation, shielding	211
	M.A.C. Cummings, S.A. Kahn Muons, Inc, Batavia, USA D. Hedin Northern Illinois University, DeKalb, Illinois, USA J.F. Kozminski Lewis University, Romeoville, Illinois, USA
	Funding: Supported in part by SBIR Grant 4738 · 10SC05447 Technological innovations in recent years have revived interest in muon colliders as the next generation energy frontier machine. Advances in muon cooling technology will make the focussing and acceleration of muons to TeV energies possible. The biggest challenge for muon colliders is that muons decay, but it is possible to build a large muon collider as a circular machine, even at multi-TeV energies, due to the greatly reduced synchrotron radiation expected from muons compared to electrons. The challenge for the detectors in such machines is overcoming the large backgrounds from muon decays in the colliding ring lattice that will inundate the interaction region (IR) and will make triggering and data reconstruction a challenge. Developing simulation tools that can reliably model the environment of the muon collider IR will be critical to physics analyses. We will need to expand the capabilities of current programs and use them to benchmark and verify results against each other. In this paper we will discuss these processes and calculate the resulting particle fluxes into the detector volume.

MOPPC038	Bethe-Heitler Muon Background at a Muon Collider	background, electron, hadron, simulation	214
	S.A. Kahn, M.A.C. Cummings, T.J. Roberts Muons, Inc, Batavia, USA D. Hedin, A.O. Morris Northern Illinois University, DeKalb, Illinois, USA J.F. Kozminski Lewis University, Romeoville, Illinois, USA
	Multi-TeV muon colliders are an important option for a future energy frontier lepton collider since synchrotron radiation in a circular machine is significantly less than that in an electron collider. For a muon collider with 750 GeV μ+μ− with 2×10¹² μ per bunch we would expect 8.6×10⁵ muon decays per meter for the two beams. Muon decays are the source of beam induced backgrounds that can affect the physics. These backgrounds include electrons from muon decays, synchrotron radiation from the decay electrons, hadrons produced by photo-nuclear interactions, coherent and incoherent beam-beam pair production and Bethe-Heitler muon production. This paper will describe a simulation of the B-H muon pair production in a muon collider. These muons can penetrate the collider ring magnets and shielding and possibly enter into the detector regions. The simulation tracks B-H muons produced from electromagnetic shower interactions in collider ring material in the range of ±200 m from the interaction point.

MOPPC039	Electron Recombination in a Dense Hydrogen Plasma	cavity, electron, plasma, ion	217
	B.T. Freemire, P.M. Hanlet IIT, Chicago, Illinois, USA M. Chung Handong Global University, Pohang, Republic of Korea M.G. Collura Politecnico di Torino, Torino, Italy M.R. Jana, C. Johnstone, T. Kobilarcik, G.M. Koizumi, M.A. Leonova, A. Moretti, M. Popovic, T.A. Schwarz, A.V. Tollestrup, Y. Torun, K. Yonehara Fermilab, Batavia, USA R.P. Johnson Muons, Inc, Batavia, USA
	Funding: US DOE under contract DE-AC02-07CH11359. A high pressure hydrogen gas filled RF cavity was subjected to an intense proton beam to study the evolution of the beam induced plasma inside the cavity. The electron recombination rate with the dense ionized hydrogen plasma has been measured under varying conditions. Recombination rates as high as 10^-7 cm³/s have been recorded. This technique shows promise in the R&D program for a muon accelerator. The use of hydrogen, both as a way to prevent breakdown in an RF cavity and as a mechanism for cooling a beam of muons, will be discussed.

MOPPC041	Control of Beam Losses in the Front End for the Neutrino Factory	proton, target, factory, solenoid	223
	C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom D.V. Neuffer Fermilab, Batavia, USA P. Snopok IIT, Chicago, Illinois, USA
	The Neutrino Factory produces neutrinos by muon decay in a storage ring. Pions are produced by firing high energy protons onto a target. Pions decay to muons, which are captured and accelerated to high energy. The target produces additionally a large background that is deposited in the muon capture front end and subsequent components. The implications of energy deposition in the front end lattice for the Neutrino Factory are addressed. Several approaches to mitigating the effect are proposed and discussed, including proton absorbers, chicane, and shielding.

MOPPC042	Higgs Boson Muon Collider Factory: h⁰, A, H Studies	factory, solenoid, simulation, dipole	226
	D.B. Cline, X.P. Ding, J.L. Lederman UCLA, Los Angeles, California, USA
	With the recent hints of the Higgs boson from the LHC and a mass near 125 GeV/c we re-propose to study and build a muon collider Higgs factory to study the Higgs in the S channel. This was first proposed in 1992 by the first author. It is essential to study the Higgs boson for clues to new physics. The formation of the DOE MAP program, recent advances in 6D μ cooling methods, simulation, and targeting make this a feasible project to initiate at this time. This collider would fit into the FNAL site.

MOPPC044	Gallium as a Possible Target Material for a Muon Collider or Neutrino Factory	target, proton, factory, interaction-region	232
	X.P. Ding UCLA, Los Angeles, California, USA J.S. Berg, H.G. Kirk, H. K. Sayed BNL, Upton, Long Island, New York, USA V.B. Graves ORNL, Oak Ridge, Tennessee, USA K.T. McDonald PU, Princeton, New Jersey, USA N. Souchlas, R.J. Weggel Particle Beam Lasers, Inc., Northridge, California, USA
	Funding: Work support by the U.S. Department of Energy in part under Awards No. DE-AC02-98CH10886 (BNL) and No. DF-FG02-92ER40695 (UCLA) We consider the potential for a free-gallium-jet as an option for the pion-production target at a Muon Collider or Neutrino Factory. Advantages of such a target choice are its liquid state at relatively low temperature, its relatively efficient meson production, and its lower activation (compared to mercury). Using the MARS15 code, we have simulated particle production initiated by incoming protons with kinetic energies (KE) between 2 and 16~GeV. For each proton beam energy, we optimized the geometric parameters of the target: the radius of the liquid jet, the incoming proton beam angle, and the crossing angle between the jet and the proton beam. We compare the quantity of generated muons using a Ga target to that from a mercury jet target.

MOPPC083	LinguaFranca - A Graphical User Interface for Accelerator Modeling	simulation, quadrupole, lattice, optics	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.

MOPPC084	G4beamline Code Development	space-charge, electron, radiation, synchrotron	334
	T.J. Roberts Muons, Inc, Batavia, USA
	Funding: Supported in part by DoE STTR grant DE-FG02-06ER86281. G4beamline is a single-particle-tracking simulation program based on Geant4, optimized specifically for beam lines. It is currently used by several hundred physicists and designers around the world, who apply it to a diverse set of interesting problems. As it includes particle decays and interactions, it is applicable to beams for which decays and interactions are important, such as modern muon facilities that involve ionization cooling. Its description language has been designed to be both versatile and user-friendly, and the program includes high-quality visualization and histogramming capabilities. This paper discusses recent code development and new features, and some interesting applications of the program. G4beamline is an open-source program freely available at http://g4beamline.muonsinc.com

MOPPD061	LHC@home: a Volunteer Computing System for Massive Numerical Simulations of Beam Dynamics and High Energy Physics Events	HOM, simulation, controls, superconducting-magnet	505
	M. Giovannozzi, F. Grey, A. Harutyunyan, N. Hoimyr, P.L. Jones, A. Karneyeu, M.A. Marquina, E. McIntosh, B. Segal, P. Skands CERN, Geneva, Switzerland D. Lombraña González CCC, 1211Geneva 23, Switzerland L. Rivkin, I. Zacharov EPFL, Lausanne, Switzerland
	Recently, the LHC@home system has been revived at CERN. It is a volunteer computing system based on BOINC which allows boosting the available CPU-power in institutional computer centers by the help of individuals that donate the CPU-time of their PCs. Currently two projects are hosted on the system, namely SixTrack and Test4Theory. The first is aimed at performing beam dynamics simulations, while the latter deals with the simulation of high-energy events. In this paper the details of the global system, as well a discussion of the capabilities of either project will be presented. Milestones of progress of the projects will also be discussed.

MOPPD082	Recent T980 Crystal Collimation Studies at the Tevatron Exploiting a Pixel Detector System and a Multi-strip Crystal Array	collimation, proton, vacuum, scattering	559
	D.A. Still, G. Annala, R.A. Carrigan, A.I. Drozhdin, T.R. Johnson, N.V. Mokhov, V. Previtali, R.A. Rivera, V.D. Shiltsev, J.R. Zagel, V.V. Zvoda Fermilab, Batavia, USA Y.A. Chesnokov, I.A. Yazynin IHEP, Moscow Region, Russia V. Guidi, A. Mazzolari INFN-Ferrara, Ferrara, Italy Yu.M. Ivanov PNPI, Gatchina, Leningrad District, Russia D. Mirarchi, S. Redaelli CERN, Geneva, Switzerland
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy through the US LHC Accelerator Research Program (LARP). With the shutdown of the Tevatron, the T-980 crystal collimation experiment at Fermilab has been successfully completed. Results of dedicated beam studies in May 2011 are described in this paper. For these studies, two multi-strip crystals were installed in the vertical goniometer. A two-plane CMS pixel detector was positioned upstream of the E03 collimator to image beam deflected by the crystals. This new enhanced hardware yielded impressive results. For the first time, a 980-GeV proton halo beam, channeled by an O-shaped crystal of the horizontal goniometer, was imaged using the pixel detector. The performance of this crystal, the first element of the collimation system, was very good. Reproducible results on the reduction of local beam losses were also obtained with an 8-strip crystal. For volume reflection these beam losses were measured with the PIN diodes and loss monitors at the E03 collimator. The long range beam losses for the channeled beam were observed using the F17 collimator one third of the ring downstream of the crystal. The measured channeling efficiency of the O-shaped crystal and the volume reflection efficiency of the 8-strip crystal were both ~70%.

MOPPR065	A Low-latency Sub-micron Resolution Stripline Beam Position Monitoring System for Single-pass Beamlines	monitoring, feedback, linear-collider, extraction	933
	P. Burrows, D.R. Bett, N. Blaskovic Kraljevic, G.B. Christian, M.R. Davis, A. Gerbershagen, C. Perry JAI, Oxford, United Kingdom R. Apsimon, B. Constance CERN, Geneva, Switzerland J. Resta-López IFIC, Valencia, Spain
	A low-latency, sub-micron resolution stripline beam position monitoring system has been developed for use in single-pass beamlines. The fast analogue front-end signal processor is based on a single-stage RF down-mixer and is combined with an FPGA-based system for digitisation and further signal processing. The system has been deployed and tested with beam at the Accelerator Test Facility at KEK. Performance results are presented on the calibration, resolution and stability of the system. A detailed simulation has been developed that is able to account for the measured performance.

TUYA01	Research and Development of Future Muon Collider	cavity, plasma, proton, emittance	1020
	K. Yonehara Fermilab, Batavia, USA
	A muon collider would provide a unique facility for future elementary-particle physics research, and present unique challenges for accelerator physics and technology. An R&D effort is underway to address major challenges in the design of a future muon collider. This talk should provide an opportunity to discuss the muon collider's challenges, present recent R&D results, and describe future prospects.

TUYA02	Overview of Asymmetric Electron Hadron Colliders	electron, ion, hadron, proton	1025
	V. Ptitsyn BNL, Upton, Long Island, New York, USA
	The first lepton-proton collider HERA at DESY completed its operation in 2007. Presently, several accelerator proposals for future electron-hadron colliders are under consideration in several laboratories from all over the world. The future accelerators intend to exceed the HERA luminosity by 2-3 orders of magnitude, as well as to cover the different ranges of center-of-mass collision energies. The research capabilities will be extended by including the collisions of electrons with heavy ions, as well as, in some designs, with polarized protons and polarized ions. The future electron-hadron colliders would serve as high-resolution microscopes able to reveal unprecedented details of the structure of nucleons and ions, including their spin content and the state of high gluon density matter. The colliders will provide us with ultimate tools to test both the ways Quantum Chromodynamics works as well as to look for new physics beyond the Standard Model. All proposed electron-hadron colliders are based on the extension of existing accelerators to accommodate the electron-hadron collisions. Advanced accelerator technologies are utilized in order to achieve the desired high luminosity.
	Slides TUYA02 [6.002 MB]

TUOAA03	Tests of Low Emittance Tuning Techniques at SLS and DAΦNE	quadrupole, emittance, coupling, alignment	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]

TUEPPB001	Interaction of Muon Beam with Plasma Developed During Ionization Cooling	plasma, wakefield, electron, simulation	1110
	S. Ahmed JLAB, Newport News, Virginia, USA K.B. Beard, T.J. Roberts Muons, Inc, Batavia, USA D.M. Kaplan, L.K. Spentzouris Illinois Institute of Technology, Chicago, Illinois, USA
	Muon collider has been envisioned as a future high energy lepton machine. High luminosity can be obtained by the ionization cooling – best suited for muons due to their short life time. In this cooling process, particles ionize material medium in which they lose momentum, thus the normalized emittance is reduced. The ionized medium is called plasma and the ionization density could increase due to the passage of multiple bunches through the material. This means that the incoming beams interact with plasma together with ionizing the medium used for cooling. It is, therefore, important to investigate the effects of background plasma on the incoming bunches. A comprehensive studies of muon beam propagation through plasma medium using EM particle-in-cell simulations. This computational study involves kinetic model, therefore, provides deep insight of the phenomena, which cannot be obtained by the conventional fluid model. The wakes excited by mu+ and mu- are different due to the beam polarity and depends on their relative densities. Externally applied axial magnetic field suppresses the wakes evolved during the interaction. The details of this study will be discussed in the paper.

TUEPPB002	Numerical Simulations of Transverse Beam Diffusion Enhancement by the Use of Electron Lens in the Tevatron Collider	electron, simulation, resonance, beam-beam-effects	1113
	V. Previtali, G. Stancari, 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)." Transverse beam diffusion for the Tevatron machine has been calculated using the Lifetrac code. The following effects were included: random noise (representing residual gas scattering, voltage noise in the accelerating cavities) lattice nonlinearities and beam-beam interactions. The time evolution of particle distributions with different initial amplitudes in Hamiltonian action has been simulated for 6 million turns, corresponding to a machine time of about 2 minutes. For each particle distribution, several cases have been considered: a single beam in storage ring mode, the collider case, and the effects of a hollow electron beam collimator

TUPPC041	A 3 TeV Muon Collider Lattice Design	quadrupole, emittance, lattice, dipole	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

TUPPC078	Proposal of an Inverse Logarithm Scaling Law for the Luminosity Evolution	luminosity, emittance, dynamic-aperture, hadron	1353
	M. Giovannozzi CERN, Geneva, Switzerland C.H. Yu IHEP, Beijing, People's Republic of China
	A scaling law for the time-dependence of the dynamic aperture, i.e., the region of phase space where stable motion occurs, was proposed in previous papers, about ten years ago. It was showed that dynamic aperture has a logarithmic dependence on time, which would be suggested by some fundamental theorems of the theory of dynamical systems. Such a scaling law was recently extended also to the intensity evolution in a storage ring. In this paper, inspired by these results, and inverse logarithm scaling law for the luminosity in a circular collider is proposed. The law is then tested against the data from the LHC physics runs and also with some examples from other machines. The results are presented and discussed in details.

TUPPC097	Computational Modeling of Electron Cloud For MEIC	electron, simulation, ion, emittance	1383
	S. Ahmed, J.D. Dolph, G.A. Krafft, T. Satogata, B.C. Yunn JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. This work is the continuation of our earlier studies on electron cloud (EC) simulations reported in IPAC'11 for the medium energy electron-ion collider (MEIC) envisioned at JLab beyond the 12 GeV upgrade of CEBAF. In this paper, we will study the EC saturation density in various MEIC operations scenarios to calculate details of the EC-induced wakefield to establish more stringent bounds on instability thresholds and determine whether EC mitigation, such as NEG coatings or solenoid fields, should be considered in the MEIC design.

TUPPC099	Optimization of Chromaticity Compensation and Dynamic Aperture in MEIC Collider Rings	sextupole, ion, dynamic-aperture, octupole	1389
	F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang JLAB, Newport News, Virginia, USA K.B. Beard Muons, Inc, Batavia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by US DOE STTR grant DE-SC0006272. The conceptual design of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab relies on an ultra-small beta-star to achieve high luminosities of up to 10³⁴ cm^-2s⁻¹. A low-beta insertion for interaction regions unavoidably induces large chromatic effects that demand a proper compensation. The present approach of chromatic compensation in the MEIC collider rings is based on a local correction scheme using two symmetric chromatic compensation blocks that includes families of sextupoles, and are placed in a beam extension area on both sides of a collision point. It can simultaneously compensate the first order chromaticity and chromatic beam smear at the IP without inducing significant second order aberrations. In this paper, we investigate both the momentum acceptance and dynamic aperture in the MEIC ion collider ring by considering the aberration effects up to the third order, such as amplitude dependent tune shift. We also explore the compensation of the third order effects by introducing families of octupoles in the extended beam area. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by US DOE STTR grant DE-SC0006272.

TUPPC102	Simulation Study of Beam-beam Effects in Ion Beams with Large Space Charge Tuneshift	space-charge, simulation, lattice, synchrotron	1398
	C. Montag 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. During low-energy operations with gold-gold collisions at 3.85 GeV beam energy, significant beam lifetime reductions have been observed due to the beam-beam interaction in the presence of large space charge tuneshifts. These beam-beam tuneshift parameters were about an order of magnitude smaller than during regular high energy operations. To get a better understanding of this effect, simulations have been performed. Recent results are presented.

TUPPD010	Helical Muon Beam Cooling Channel Engineering Design	cavity, solenoid, simulation, beam-cooling	1425
	G. Flanagan, R.P. Johnson, G.M. Kazakevich, F. Marhauser, M.L. Neubauer Muons, Inc, Batavia, USA V.S. Kashikhin, M.L. Lopes, G.V. Romanov, M.A. Tartaglia, K. Yonehara, M. Yu, A.V. Zlobin Fermilab, Batavia, USA
	Funding: Supported in part by DOE STTR Grant DE-SC0006266 The Helical Cooling Channel (HCC), a novel technique for six-dimensional (6D) ionization cooling of muon beams, has shown considerable promise based on analytic and simulation studies. However, the implementation of this revolutionary method of muon cooling requires new techniques for the integration of hydrogen-pressurized, high-power RF cavities into the low-temperature superconducting magnets of the HCC. We present the progress toward a conceptual design for the integration of 805 MHz RF cavities into a 10 T Nb3Sn based HCC test section. We include discussions on the pressure and thermal barriers needed within the cryostat to maintain operation of the magnet at 4.2 K while operating the RF and energy absorber at a higher temperature. Additionally, we include progress on the Nb3Sn helical solenoid design

TUPPD011	Studies of the Twin Helix Parametric-resonance Ionization Cooling Channel with COSY INFINITY	simulation, resonance, emittance, quadrupole	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.

TUPPD012	Complete Muon Cooling Channel Design and Simulations	emittance, dipole, simulation, solenoid	1431
	C. Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson Muons, Inc, Batavia, USA Y.S. Derbenev, V.S. Morozov JLAB, Newport News, Virginia, USA D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA
	Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittances required for an energy-frontier muon collider. However, it has not yet been demonstrated that the various proposed cooling subsystems can be consolidated into an integrated end-to-end design. Presented here are concepts to address the matching of transverse emittances between subsystems through an extension of the theoretical framework of the Helical Cooling Channel (HCC), which allows a general analytical approach to guide the transition from one set of cooling channel parameters to another.

TUPPD013	Bunch Coalescing in a Helical Channel	acceleration, emittance, simulation, factory	1434
	C. Y. Yoshikawa, C.M. Ankenbrandt Muons, Inc, Batavia, USA D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA
	Funding: Supported in part by SBIR Grant 4725 · 09SC02739. A high-luminosity Muon Collider requires bunch recombination for optimal luminosity. In this paper, we take advantage of the large slip factor in a helical transport channel (HTC) to coalesce bunches of muons into a single one over a shorter distance than can be achieved over a straight channel. The coalescing subsystem that is designed to merge 9 bunches has a horizontal length of ~105m and is able to achieve efficiencies of 99.7%, 98.4%, and 94.2% for 9, 11, and 13 bunches, respectively, where each bunch has emittances expected at the end of an HCC. Simplified designs incorporating fill factors for RF cavities of ~25% and ~50% obtained efficiencies of 96%, 94-95%, and 90-91% for 9, 11, and 13 bunches, respectively. The efficiencies above do not include decay losses, which would be ~8% for muons with kinetic energy of 200 MeV.

TUPPP092	Renovated Two-stage Bunch Compressor for the International Linear Collider	wiggler, positron, linac, linear-collider	1801
	S. Seletskiy BNL, Upton, Long Island, New York, USA N. Solyak Fermilab, Batavia, USA
	The International Linear Collider (ILC) utilizes a Bunch Compressor (BC) in the Damping Ring to Main Linac Transfer Line (RTML) that compresses the RMS bunch length from 6 mm to 300 micrometers before sending the beam to the Main Linac. It was decided to utilize a two stage BC for the design baseline, since it provides an additional option for the ILC to work with 150 micrometers long bunches and reduces the energy spread at the RTML exit under normal operational conditions. In this paper we report the new design of the optimized two-stage bunch compressor.

TUPPR008	One 233 km Tunnel for Three Rings: e⁺e^-, p-pbar, and μ⁺+μ⁻	dipole, emittance, luminosity, lattice	1828
	G.T. Lyons, L.M. Cremaldi, A. Datta, M. Duraisamy, T.H. Luo, D.J. Summers UMiss, University, Mississippi, USA
	Funding: Supported by DE-FG05-91ER40622 In 2001, a cost analysis was conducted to build a 233 km circumference tunnel in northern Illinois for a Very Large Hadron Collider (VLHC). Here we outline the implementations of e⁺e⁻, proton anti-proton, and μ⁺+ μ⁻ collider rings in such a tunnel using recent technological innovations. The 500 GeV e⁺e⁻ collider employs a Crab Waist Crossing, ultra low emittance damped bunches, a vertical IP focal length of 0.06 cm, 12 GV of superconducting RF, and 0.026 Tesla low coercivity, grain oriented silicon steel/concrete dipoles. The 40 TeV proton anti-proton collider uses the high intensity Fermilab anti-proton source, exploits high cross sections for proton anti-proton production of high mass states, and uses 2 Tesla 0.005% ultra low carbon steel/YBCO superconductor magnets run with liquid neon. The 40 TeV muon ring ramps the 2 Tesla superconducting magnets at 8 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 2 to 20 TeV in 72 orbits with 72% survival, and mitigates neutrino radiation with a phase shifting, roller coaster FODO lattice.* * G. T. Lyons, http://arxiv.org/pdf/1112.1105

TUPPR011	Six-dimensional Bunch Merging for Muon Collider Cooling	emittance, simulation, kicker, solenoid	1831
	R.B. Palmer, R.C. Fernow BNL, Upton, Long Island, New York, USA D.V. Neuffer Fermilab, Batavia, USA
	Funding: Work supported by US Department of Energy under contracts DE-AC02-98CH10886 and DE-AC02-07CH11359. Muons for a Muon Collider are diffusely produced from pion decay. They are first phase rotated into a trains of bunches. The trains are ionization cooled in all six dimensions until they can be merged into single bunches, one of each sign. They are then further cooled in six dimensions before acceleration and injection into the collider. This merging matches more efficiently into the second phase of cooling if the merging is also in six dimensions. A scheme to do this is proposed. Groups of 3, of the initial 12, bunches are merged longitudinally into 4 longer bunches, using rf with multiple harmonics. These 4 are then kicked into 4 separate (trombone) channels of different lengths to bring them to closely packed transverse locations at the same time. Here they are captured into a single bunch with now increased transverse emittance.

TUPPR013	Design Integration and Vision Sharing for the ILC	lattice, linear-collider, linac, damping	1837
	B. List, L. Hagge, S. Sühl, N.J. Walker, N. Welle DESY, Hamburg, Germany
	The Global Design Effort for the International Linear Collider is currently preparing the Technical Design Report, which will be released in early 2013. The starting point of a consistent and correct design is the accelerator lattice, which defines the layout of the machine. Integrating the lattice geometrically and optically provides the basis for civil engineering and conventional facilities planning and finally the cost estimate. Tools that provide three-dimensional visualization of the lattice and tunnel help to perform the design integration and allow sharing a common vision of the final accelerator. We will present the process that was established to arrive at such an integrated design and the tools that were developed to support that process by analyzing and visualizing lattice files.

TUPPR022	Traditional Final Focus System for CLIC	luminosity, lattice, linear-collider, quadrupole	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.

TUPPR024	CLIC Recombination Scheme for the Low Energy Operation Mode	factory, acceleration, luminosity, linac	1864
	A. Gerbershagen, D. Schulte CERN, Geneva, Switzerland P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	The CLIC recombination scheme is a concept of multiplication of the drive beam frequency in order to generate a 12 GHz RF wave for the main beam acceleration. CLIC is designed to be operated in nominal and in low energy modes. The low energy operation modes require the train length to be increased by different factors in order to maintain the same level of luminosity. Also the number of initial trains that are merged to form each final train is changed. The combination scheme must be able to accommodate and recombine both long and short trains for nominal and low energy CLIC operation modes. The recombination hence becomes a non-trivial process and makes the correction of the errors in the drive beam more challenging. The present paper describes in detail the recombination process and its consequences.

TUPPR048	Short RF Pulse Linear Collider	linac, linear-collider, klystron, wakefield	1924
	C.-J. Jing, S.P. Antipov, A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, W. Gai, J.G. Power ANL, Argonne, USA
	Funding: DOE SBIR program under Contractor #DE-SC0004320 In general, a high gradient is desirable for future linear collider designs because it can reduce the total linac length. More importantly, the efficiency and the cost to sustain the high gradient should also be considered in the optimization process of an overall design. In this article, we explore a parametric territory of short rf pulse, high group velocity, high frequency, and high gradient, etc., that may lead to an affordable high energy linear collider in the future.

TUPPR076	The LHeC Project Development Beyond 2012	electron, linac, cavity, dipole	1999
	F. Zimmermann, O.S. Brüning CERN, Geneva, Switzerland M. Klein The University of Liverpool, Liverpool, United Kingdom
	The LHeC study group is finalizing a Conceptual Design Report for publication early in 2012. This paper discusses the next steps required for developing a Technical Design Report and highlights the R&D developments, test facilities and implementation studies that need to be addressed over the coming years. Particular emphasize will be given to similarities with other ongoing accelerator and detector studies, and to a discussion of possible international collaboration efforts.

TUPPR077	Simulation Studies for the LHC Long-Range Beam-Beam Compensators	optics, simulation, resonance, betatron	2002
	T.L. Rijoff, R.J. Steinhagen, F. Zimmermann CERN, Geneva, Switzerland
	The LHC performance and the minimum crossing angle are limited by long-range beam-beam collisions. Wire compensators can mitigate part of the long-range effects and may allow for smaller crossing angles, smaller β^*, or higher beam intensity. A prototype long-range wire compensator should be installed in the LHC by 2014/15. We report simulation studies examining and comparing the efficiency of the wire compensation, in terms of tune footprint or dynamic aperture, at various candidate locations, with different wire shapes, and for varying transverse distance from the beam.

TUPPR078	LEP3: A High Luminosity e⁺e⁻ Collider in the LHC Tunnel to Study the Higgs Boson	luminosity, positron, emittance, synchrotron	2005
	F. Zimmermann, M. Koratzinos CERN, Geneva, Switzerland A.P. Blondel DPNC, Genève, Switzerland M. Zanetti MIT, Cambridge, Massachusetts, USA
	Recent indications from two LHC experiments suggest that the Higgs boson might be light, within the mass range 115-130 GeV. Such object could be studied at an e⁺e⁻ collider with about 240 GeV centre-of-mass energy. A corresponding Higgs factory – “LEP3” - could be installed in the LHC tunnel, reducing its cost and also allowing for a second life of the two LHC general-purpose detectors. We present preliminary accelerator and beam parameters for LEP3 tailored so as to provide a peak luminosity of 10³⁴/cm²/s at each of two experiments, while respecting a number of constraints including beamstrahlung limits. At this luminosity around 20,000 Higgs events per year per experiment could be obtained for a Standard Model Higgs boson with a mass of 115-130 GeV. For the parameters considered the estimated luminosity lifetime is about 12 minutes, and the synchrotron radiation losses are 50 MW per beam. High operational efficiency requires two rings: a low emittance collider storage ring operating at constant energy, and a separate accelerator to top up the colliding beams every few minutes. The alternative of a larger ring collider installed in a new, bigger tunnel will also be discussed.

TUPPR079	Ion Polarization in the MEIC Figure-8 Ion Collider Ring	polarization, ion, proton, resonance	2008
	V.S. Morozov, Y.S. Derbenev, Y. Zhang JLAB, Newport News, Virginia, USA P. Chevtsov Paul Scherrer Institut, Villigen, Switzerland Y. Filatov MIPT, Dolgoprudniy, Moscow Region, Russia A.M. Kondratenko, M.A. Kondratenko Science and Technique Laboratory Zaryad, Novosibirsk, Russia
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The nuclear physics program envisaged at the Medium-energy Electron-Ion Collider (MEIC) currently being developed at the Jefferson Lab calls for collisions of 3-11 GeV/c longitudinally polarized electrons and 20-100 GeV/c, in equivalent proton momentum, longitudinally or transversely polarized light ions. In this paper, we present a scheme based on figure-8 shaped booster and collider rings that provides the required ion polarization arrangement in the MEIC's ion collider ring. 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.

TUPPR082	MEIC Design Progress	ion, electron, booster, polarization	2014
	Y. Zhang, Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, R. Li, F. Lin, V.S. Morozov, E.W. Nissen, F.C. Pilat, T. Satogata, C. Tennant, B. Terzić, B.C. Yunn JLAB, Newport News, Virginia, USA D.P. Barber DESY, Hamburg, Germany Y. Filatov JINR, Dubna, Russia C. Hyde Old Dominion University, Norfolk, Virginia, USA A.M. Kondratenko Science and Technique Laboratory Zaryad, Novosibirsk, Russia S.L. Manikonda, P.N. Ostroumov ANL, Argonne, USA M.K. Sullivan SLAC, Menlo Park, California, USA
	Funding: Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and No. DE-AC02-06CH11357. This paper will report the recent progress in the conceptual design of MEIC, a high luminosity medium energy polarized ring-ring electron-ion collider at Jefferson lab. The topics and achievements that will be covered are design of the ion large booster and the ERL-circulator-ring-based electron cooling facility, optimization of chromatic corrections and dynamic aperture studies, schemes and tracking simulations of lepton and ion polarization in the figure-8 collider ring, and the beam-beam and electron cooling simulations. A proposal of a test facility for the MEIC electron cooler will also be discussed.

TUPPR097	Modeling and Simulation of LHC Beam-Based Collimator Setup	alignment, beam-losses, simulation, emittance	2059
	G. Valentino, N.J. Sammut University of Malta, Information and Communication Technology, Msida, Malta R.W. Assmann, F. Burkart, S. Redaelli, A. Rossi, D. Wollmann CERN, Geneva, Switzerland L. Lari IFIC, Valencia, Spain
	In the 2011 Large Hadron Collider run, collimators were aligned for proton and heavy ion beams using a semi-automatic setup algorithm. The algorithm provided a reduction in the beam time required for setup, an elimination of beam dumps during setup and higher accuracy with respect to manual alignment. A collimator setup simulator was developed based on a Gaussian model of the beam distribution as well as a parametric model of the beam losses. A time-varying beam loss signal can be simulated for a given collimator movement into the beam. The simulation results and comparison to measurement data obtained during collimator setups and dedicated fills for beam halo scraping are presented. The simulator will then be used to develop a fully automatic collimator alignment algorithm.

TUPPR098	Comparison of LHC Collimator Beam-Based Alignment Centers to BPM-Interpolated Centers	alignment, injection, hadron, collimation	2062
	G. Valentino, N.J. Sammut University of Malta, Information and Communication Technology, Msida, Malta R.W. Assmann, R. Bruce, G.J. Müller, S. Redaelli, A. Rossi, G. Valentino CERN, Geneva, Switzerland L. Lari IFIC, Valencia, Spain
	The beam centers at the Large Hadron Collider collimators are determined by beam-based alignment, where both jaws of a collimator are moved in separately until a loss spike is detected on a Beam Loss Monitor downstream. Orbit drifts of more than a few hundred micrometers cannot be tolerated, as they would reduce the efficiency of the collimation system. Beam Position Monitors (BPMs) are installed at various locations around the LHC ring, and a linear interpolation of the orbit can be obtained at the collimator positions. In this paper, the results obtained from beam-based alignment are compared with the orbit interpolated from the BPM data throughout the 2011 LHC proton run. The stability of the orbit determined by collimator alignment during the run is evaluated.

WEXA01	The High Intensity Horizon at Fermilab	proton, kaon, superconducting-RF, linac	2065
	R.S. Tschirhart Fermilab, Batavia, USA
	Fermilab’s high intensity horizon is “Project-X” which is a US led initiative with strong international participation that aims to realize a next generation proton source that will dramatically extend the reach of Intensity Frontier research. The Project-X research program includes world leading sensitivity in long-baseline and short-baseline neutrino experiments, a rich program of ultra-rare muon and kaon decays, opportunities for next-generation electric dipole moment experiments and other nuclear/particle physics probes, and a platform to investigate technologies for next generation energy applications. A wide range of R&D activities has been started to support mission critical accelerator subsystems, such as high-gradient superconducting RF accelerating structures, efficient RF power systems, cryo-modules and cryogenic refrigeration plants, advanced beam diagnostics and instrumentation, high-power targetry, as well as the related infrastructure and civil construction preparing for a construction start as early as 2017. The status and prospects of developing the accelerator design, research program, and associated collaborations will be presented. * The Project X program spans several Sub Classifications: A08, A14 A17, A21, A28.
	Slides WEXA01 [9.216 MB]

WEYA03	Overview of B-Factories	emittance, sextupole, injection, quadrupole	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]

WEXB03	Protecting Accelerator Control Systems in the Face of Sophisticated Cyber Attacks	controls, target, monitoring, neutron	2101
	S.M. Hartman ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725 Recent events at ORNL and the knowledge of the use of the STUXNET virus in another country illustrate the vulnerability of advanced control systems to increasingly intelligent cyber attacks. The threat is clearly evolving and escalating, and techniques for mitigation are clearly of interest to the broader accelerator community. Risks associated with remote access must be balanced against operational efficiency and operating models. This talk should review the ongoing evolution of system architecture and security that permit effective facility operation while protecting against such harmful intrusions.
	Slides WEXB03 [6.747 MB]

WEOBA03	Beam Tests of a High Pressure Gas-Filled Cavity for a Muon Collider	cavity, electron, ion, pick-up	2131
	T.A. Schwarz, M.A. Leonova, A. Moretti, M. Popovic, A.V. Tollestrup, K. Yonehara Fermilab, Batavia, USA M. Chung Handong Global University, Pohang, Republic of Korea B.T. Freemire, P.M. Hanlet, Y. Torun IIT, Chicago, Illinois, USA R.P. Johnson Muons, Inc, Batavia, USA
	Funding: US DOE under contract DE-AC02-07CH11359. One of the greatest challenges in constructing a Muon Collider is cooling the hot muons into a focused beam after their production. Because the beam must be cooled quickly before the muons decay, compact cooling designs require high gradient cavities inside strong magnetic fields. Unfortunately, due to focused field emission, an external magnetic field degrades the performance of the cavity below what is required for a muon collider. High-pressure gas inside the cavity has been proposed to both mitigate this effect, as well as serve as an absorber for transversely cooling the muon beam. A prototype of a high pressure gas-filled cavity is currently being studied at the Muon Test Area at Fermilab. The experimental setup as well as several measurements of the physics and performance of the apparatus while operating in a 400-MeV proton beam will be discussed.
	Slides WEOBA03 [6.912 MB]

WEPPC007	Image Processing for Characterization of Surfaces of Superconducting RF Cavities	cavity, superconductivity, LabView, linear-collider	2218
	M. Wenskat, S. Aderhold, E. Elsen, S. Karstensen, F. Schlander, L. Steder DESY, Hamburg, Germany
	Funding: ILC HiGrade Optical inspection of finished Nb superconducting RF cavities has worldwide been established as an important tool for identification of field limiting surface features. Single defects in a single cell of a 9-cell cavity may severely constrain the maximum gradient while the micro-structure in the vicinity of a welding seam could affect the quench behavior. DESY has automated the imaging of critical cavity surface areas, in particular those of high magnetic field. With resolution of ~10 μm2 the information volume is large and the systematic examination becomes a necessity. The development of image processing algorithms has been started with two goals: automatic characterization of cavity surface properties and defect detection. The former results aid the quality assessment of cavities after manufacture; the latter serves to push the gradient performance. The status and prospects of the image processing for the European XFEL and ILC will be presented.

WEPPC033	RF and Surface Properties of Bulk Niobium and Niobium Film Samples	niobium, electron, quadrupole, 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.

WEPPC054	Resonance Excitation of Longitudinal High Order Modes in Project X Linac	HOM, linac, factory, kaon	2336
	A.I. Sukhanov, M.H. Awida, I.V. Gonin, T.N. Khabiboulline, A. Lunin, N. Solyak, V.P. Yakovlev Fermilab, Batavia, USA
	Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.

WEPPC085	Engineering of a Superconducting 400 MHz Crabbing Cavity for the LHC HiLumi Upgrade	cavity, luminosity, niobium, SRF	2411
	D. Gorelov, T.L. Grimm Niowave, Inc., Lansing, Michigan, USA S.U. De Silva, J.R. Delayen ODU, Norfolk, Virginia, USA
	Funding: This work is supported by the US DOE-HEP SBIR/STTR program and the US DOE through the US LHC Accelerator Research Program (LARP). The recently developed new simplified design for the 400 MHz LHC crabbing cavity presents attractive properties compared to conventional designs. The proposed approach can be equally compact in both transverse dimensions and allows horizontal as well as vertical deflection of the beam in the collider. The significant modification of the parallel-bar design with the bars merged to the side walls of the cavity gives improved properties, such as better mode separation and reduced surface fields. A transverse deflecting voltage of 3 to 5 MV in a single cavity can be expected with the peak surface electric field lower then 50 MV/m and peak magnetic field below 100 mT. This paper presents engineering issues of the proof-of-concept crabbing cavity design and discusses the manufacturing techniques. The paper discusses present status of the project including fabrication of the niobium cavity, as well as room temperature and cryogenic testing. J.R. Delayen, S.U. De Silva, "Design of Superconducting Parallel-Bar Deflecting/Crabbing Cavities with Improved Properties," Proc. of 2011 PAC, New York, NY, USA, 2011, p. 10²¹.

WEPPC112	Development of a Fundamental Power Coupler for High-Current Superconducting RF Cavity	simulation, cavity, linac, electron	2483
	P. Jain Stony Brook University, Stony Brook, USA S.A. Belomestnykh, I. Ben-Zvi, W. Xu 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. DOE and by the DOE grant DE-SC0002496 to Stony Brook University. Brookhaven National Laboratory has undertaken a project to design a five-cell superconducting 703.75 MHz RF cavity for the Energy Recovery Linac (ERL) and the planned RHIC electron cooler. The earlier developed cavity, viz., the BNL1 is fed by a klystron using a co-axial Fundamental Power Coupler (FPC), which delivers 50 kW of cw RF power to the cavity. During the cavity operation, it has been observed that a 5 K cooling line intercept in the FPC introduces undesirable microphonics. A modification in the existing FPC has been planned to determine the feasibility of getting rid of the 5 K cooling line. The modified coupler will be incorporated in the newly designed, under construction BNL3 cavity. In order to accommodate this modification, peak microphonics of 12 Hz and 20 kW of cw RF power will be considered. This paper describes the design of the new FPC starting from the analysis of thermal profile along its length from first principles.

WEPPD027	Global and Local Loss Suppression in the UA9 Crystal Collimation Experiment	collimation, ion, proton, simulation	2561
	W. Scandale LAL, Orsay, France S. Montesano CERN, Geneva, Switzerland
	UA9 was operated in the CERN-SPS for some years in view of investigating the feasibility of the halo collimation assisted by bent crystals. Two-millimeter-long silicon crystals, with bending angles of about 150 mirrored, are used as primary collimators. The crystal collimation process is obtained consistently through channeling with high efficiency. The loss profiles in the area of the crystal-collimator setup and in the downstream dispersion suppressor area show a steady reduction of slightly less than one order of magnitude at the onset of the channeling process. This result holds both for protons and for lead-ions. The corresponding loss map in the accelerator ring is accordingly reduced. These observations strongly support our expectation that the coherent deflection of the beam halo by a bent crystal should enhance the collimation efficiency in hadron colliders, such as LHC. for the UA9 Collaboration

WEPPD036	Energy Flow and Deposition in a 4-MW Muon Collider Target System	target, shielding, radiation, factory	2588
	N. Souchlas, R.J. Weggel Particle Beam Lasers, Inc., Northridge, California, USA X.P. Ding UCLA, Los Angeles, California, USA V.B. Graves ORNL, Oak Ridge, Tennessee, USA H.G. Kirk, H. K. Sayed BNL, Upton, Long Island, New York, USA K.T. McDonald PU, Princeton, New Jersey, USA
	Funding: Work support by the U.S. Department of Energy in part under Award No. DE-AC02-98CH10886 The design of the target station for a 4-MW Muon Collider or a Neutrino Factory is evolving to include more space for services to the magnets and internal tungsten shielding, as well as consideration of removing the 5-T resistive copper coils, thereby reducing the peak field from 20 to 15 T. Simulations with MARS15 have been performed to verify that these revisions preserve sufficient shielding that the peak power deposition everywhere in the superconducting magnets will be less than 0.1 mW/g, permitting at least a 10-year operational lifetime against radiation damage to the organic insulators.

WEPPD037	Shielding of Superconducting Coils for a 4-MW Muon-Collider Target System	shielding, target, interaction-region, factory	2591
	R.J. Weggel, N. Souchlas Particle Beam Lasers, Inc., Northridge, California, USA X.P. Ding UCLA, Los Angeles, California, USA V.B. Graves ORNL, Oak Ridge, Tennessee, USA H.G. Kirk, H. K. Sayed BNL, Upton, Long Island, New York, USA K.T. McDonald PU, Princeton, New Jersey, USA
	Funding: Work support by the U.S. Department of Energy in part under Award No. DE-AC02-98CH10886 The target system envisioned for a Muon Collider/Neutrino Factory features a liquid Hg jet target immersed in a 20-T solenoidal field. Field quality limits intercoil gaps to ~ 40% of the O.D. of the flanking coils. Longitudinal sag of the tungsten shielding vessels limits their length to ~ 7 m. Support members adequate to resist intercryostat axial forces require an aggregate cross section of ~ 0.1 m²; the cryogenic heat leakage may be large. The innermost shielding vessel wall can be adequately cooled by helium gas only if its pressure is ~ 10 atm and its velocity is ~ 200m/s. However, the analysis in this paper found none of these engineering challenges to be insurmountable.

WEPPD038	Mercury Handling for the Target System for a Muon Collider	target, shielding, proton, factory	2594
	V.B. Graves ORNL, Oak Ridge, Tennessee, USA X.P. Ding UCLA, Los Angeles, California, USA H.G. Kirk, H. K. Sayed BNL, Upton, Long Island, New York, USA K.T. McDonald PU, Princeton, New Jersey, USA N. Souchlas, R.J. Weggel Particle Beam Lasers, Inc., Northridge, California, USA
	Funding: Work supported in part by US DOE Contract NO.~DE-AC02-98CHI10886 and DE-AC05-00OR22725. The baseline target concept for a Muon Collider or Neutrino Factory is a free-stream mercury jet within a 20-T magnetic field being impacted by an 8-GeV proton beam. A pool of mercury serves as a receiving reservoir for the mercury and a dump for the unexpended proton beam. Design issues discussed in this paper include the nozzle, splash mitigation in the mercury pool, the mercury containment vessel, and the mercury recirculation system.

WEPPD074	Issues and Feasibility Demonstration of Positioning Closed Loop Control for the CLIC Supporting System Using a Test Mock-up with Five Degrees of Freedom	alignment, controls, feedback, linear-collider	2696
	M. Sosin, M. Anastasopoulos, N. Chritin, J. Kemppinen, H. Mainaud Durand, V. Rude, G. Sterbini, S. griffet CERN, Geneva, Switzerland
	Since several years, CERN is studying the feasibility of building a high energy e⁺ e⁻ linear collider: the CLIC (Compact LInear Collider). One of the challenges of such a collider is the pre-alignment precision and accuracy requirement on the transverse positions of the linac components, which is typically 14 μm over a window of 200 m. To ensure the possibility of positioning within such tight constraints, CERN Beams Department’s Survey team has worked intensively at developing the methods and technology needed to achieve that objective. This paper describes activities which were performed on a test bench (mock-up) with five degrees of freedom (DOF) for the qualification of control algorithms for the CLIC supporting system active-pre-alignment. Present understanding, lessons learned (“know how”), issues of sensors noise and mechanical components nonlinearities are presented.

WEPPP045	Beam-breakup Analysis for an Annular Cherenkov High Gradient Wakefield Accelerator	wakefield, simulation, vacuum, electron	2822
	A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio, USA A. Altmark LETI, Saint-Petersburg, Russia
	Funding: This work is supported by the SBIR Program of the US Department of Energy. A complete analytical solution for Cherenkov wakefields generated by an azimuthally asymmetric annular beam propagating in a coaxial two-channel dielectric structure is presented. The transformer ratio of the annular beam Cherenkov wakefield accelerator initially proposed by R. Keinigs, M. Jones* is dramatically increased in comparison to a collinear cylindrical wakefield accelerating structure. A particle-Green's function beam dynamics code BBU-3000** to study beam breakup effects has been upgraded to incorporate annular drive beams and coaxial dielectric wakefield accelerating structures. Beam dynamics simulations of the annular drive beam with asymmetric charge distributions have been carried out to determine the sensitivity of this method to beam imperfections in GHz and THz frequency ranges. R. Keinigs, M. Jones, Proc. 7th Int. Conf. High-Power Part. Beams, Beams’88, Karlsruhe, Germany, 864 (1988). **P. Schoessow et al., AIP Conference Proceedings 1299, 262 (2010).

WEPPP066	Performance Simulations of a Phase Stabilization System Prototype for CTF3	feedback, kicker, simulation, linac	2858
	A. Gerbershagen, T. Persson, D. Schulte, P.K. Skowroński CERN, Geneva, Switzerland P. Burrows, G.B. Christian Oxford University, Physics Department, Oxford, Oxon, United Kingdom A. Gerbershagen, C. Perry JAI, Oxford, United Kingdom E. Ikarios National Technical University of Athens, Athens, Greece
	The CLIC drive beam provides RF power for acceleration of the main beam, and hence the drive beam’s longitudinal phase tolerances are very tight. A feedforward chicane consisting of four electromagnetic kickers is proposed as a correction system for the phase errors, which should allow loosening of the tolerances. A prototype of such a chicane system, developed by CERN, INFN and the University of Oxford, is planned to be installed at CFT3 in 2012. The present paper summarizes the parameters of the planned phase correction system and presents simulations, which are used to make predictions of the performance of such a feedforward system at CTF3.

WEPPP068	Latest Performance Results from the FONT5 Intra-train Beam Position and Angle Feedback System at ATF2	feedback, kicker, extraction, linear-collider	2864
	D.R. Bett, R. Apsimon, N. Blaskovic Kraljevic, P. Burrows, G.B. Christian, M.R. Davis, A. Gerbershagen, C. Perry JAI, Oxford, United Kingdom B. Constance CERN, Geneva, Switzerland J. Resta-López IFIC, Valencia, Spain
	A prototype Interaction Point beam-based feedback system for future electron-positron colliders, such as the International Linear Collider, has been designed and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The FONT5 intra-train feedback system aims to stabilize the beam orbit by correcting both the position and angle jitter in the vertical plane on bunch-to-bunch time scales, providing micron-level stability at the entrance to the ATF2 final-focus system. The system comprises three stripline beam position monitors (BPMs) and two stripline kickers, custom low-latency analogue front-end BPM processors, a custom FPGA-based digital processing board with fast ADCs, and custom kicker-drive amplifiers. The latest results from beam tests at ATF2 will be presented, including the system latency and correction performance.

WEPPR004	Effect of Beam-beam Interactions on Stability of Coherent Oscillations in a Muon Collider	luminosity, resonance, lattice, quadrupole	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.

WEPPR050	Future Colliders Based on a Modulated Proton Bunch Driven Plasma Wakefield Acceleration	electron, plasma, proton, wakefield	3039
	G.X. Xia, A. Caldwell MPI-P, München, Germany P. Muggli MPI, Muenchen, Germany
	Recent simulation shows that a self-modulated high energy proton bunch can excite large amplitude plasma wakefields and accelerate an external electron bunch to higher energies. Based on this scheme, future colliders, either an electron-positron linear collider (e⁺e⁻ collider) or an electron-hadron collider (e.g. LHeC) can be conceived. In this paper, we discuss some key design issues for an e⁺e⁻ collider and a high energy LHeC collider, based on the existing infrastructure of the CERN accelerator complex. A. Caldwell, K. Lotov, Plasma wakefield acceleration with a modulated proton bunch, arXiv: 1105.1292 (2011).

WEPPR093	Impedance Budget for Crab Cavity in MEIC Electron Ring	impedance, electron, cavity, ion	3153
	S. Ahmed, G.A. Krafft, B.C. Yunn JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab has been envisioned as a first stage high energy particle accelerator beyond the 12 GeV upgrade of CEBAF. The estimate of impedance budget is important from the view point of beam stability and matching with other accelerator components driving currents. The detailed study of impedance budget for electron ring has been performed by considering the current design parameters of the e-ring. A comprehensive picture of the calculations involved in this study has been illustrated in the paper.

THYA01	High Field Magnet Developments	dipole, quadrupole, luminosity, alignment	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]

THXB01	Interaction of Muon Beam with Plasma Developed During Ionization Cooling	plasma, wakefield, electron, simulation	3200
	S. Ahmed JLAB, Newport News, Virginia, USA K.B. Beard, T.J. Roberts Muons, Inc, Batavia, USA D.M. Kaplan, L.K. Spentzouris Illinois Institute of Technology, Chicago, Illinois, USA
	Muon collider has been envisioned as a future high energy lepton machine. High luminosity can be obtained by the ionization cooling – best suited for muons due to their short life time. In this cooling process, particles ionize material medium in which they lose momentum, thus the normalized emittance is reduced. The ionized medium is called plasma and the ionization density could increase due to the passage of multiple bunches through the material. This means that the incoming beams interact with plasma together with ionizing the medium used for cooling. It is, therefore, important to investigate the effects of background plasma on the incoming bunches. A comprehensive studies of muon beam propagation through plasma medium using EM particle-in-cell simulations. This computational study involves kinetic model, therefore, provides deep insight of the phenomena, which cannot be obtained by the conventional fluid model. The wakes excited by mu+ and mu- are different due to the beam polarity and depends on their relative densities. Externally applied axial magnetic field suppresses the wakes evolved during the interaction. The details of this study will be discussed in the paper.
	Slides THXB01 [4.584 MB]

THYB01	Beam-beam Limit in a Hadron Collider	luminosity, emittance, simulation, resonance	3208
	K. Ohmi KEK, Ibaraki, Japan
	Beam-beam limit phenomenon is observed in degradation of luminosity lifetime and/or beam life time in hadron colliders, especially in LHC. We focus the luminosity degradation in this paper. Various effects to degrade the luminosity grow severe in a high beam intensity. Coherent beam-beam instability, incoherent beam-beam emittance growth and those cupeled with lattice errors, external noises, intra-beam scattering. The beam-beam limit in an ideal machine and a machine with above errors is discussed with theory and simulation. Experimental results are reviewed and compare with the theory and simulations.
	Slides THYB01 [4.712 MB]

THEPPB012	Pressure Acoustic Waves in Positron Production Targets for Future Lepton Colliders	target, positron, photon, linear-collider	3257
	O.S. Adeyemi, V.S. Kovalenko, L.I. Malysheva, G.A. Moortgat-Pick, A. Ushakov University of Hamburg, Hamburg, Germany A.F. Hartin DESY, Hamburg, Germany F. Staufenbiel DESY Zeuthen, Zeuthen, Germany
	Funding: This work is supported by the German Federal Ministry of Education and Research, Joint Research Project R&D Accelerator "Spin Management", contract number 05H10GUE Future high energy lepton colliders demand high luminosities to achieve its physics goals. For the electron-positron linear collider, the generation of positrons is a non-trivial problem: the positron production target has to a survive huge amount of energy deposited by the bombardment of intense beams of electrons or photons. This causes a rapid increase of the temperature in the target within a very short time period. The resulting thermal stress induces pressure waves and can substantially shorten the operating life-span of for the target material. In this work, we study linear and effects of induced stress through pressure acoustic waves using a hydrodynamic model. The survivability issue of the target is discussed.

THPPD016	Construction and Measurement of Novel Adjustable Permanent Magnet Quadrupoles for CLIC	quadrupole, permanent-magnet, multipole, 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.

THPPD028	Studies on the LHC Superconducting Circuits and Routine Qualification of Their Functionalities	dipole, cryogenics, hadron, target	3563
	M. Pojer, G. D'Angelo, R. Mompo, R. Schmidt, M. Solfaroli Camillocci CERN, Geneva, Switzerland
	The Large Hadron Collider (LHC) is systematically undergoing periods of maintenance stop (either 4-5 days stops or longer Christmas breaks), after which some of the superconducting circuits (or the totality of them) have to be re-commissioned to check the correct functionality of all powering and protection systems. Detailed procedures have been developed during the past few years and they have been optimized to increase powering tests efficiency, thus reducing beam downtime. The approach to the routine qualification of the LHC powering systems is described in this paper. During 2011 technical stops, some particular studies on the superconducting circuits were performed, to assess the quality of the superconducting splices of individually powered magnets and to study the quench propagation in the main magnet bus-bars. The methodology of these tests and some results are also presented.

THPPD029	Machine Availability at the Large Hadron Collider	luminosity, cryogenics, controls, hadron	3566
	M. Pojer, R. Schmidt, M. Solfaroli Camillocci, S. Wagner CERN, Geneva, Switzerland
	One of the most important parameters for a particle accelerator is its uptime, the period of time when it is functioning and available for use. In its second year of operation, the Large Hadron Collider (LHC) has experienced very high machine availability, which is one of the ingredients of its brilliant performance. Some of the strategies followed to increase MTBF are described in the paper. The approach of periodic maintenance stops, often questioned, is also discussed. Some considerations on the ideal length of a physics fill are also drawn.

THPPD034	Quench Performance and Field Quality of 90-mm Nb3Sn Quadrupoles of TQC Series	quadrupole, dipole, 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, quadrupole, 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, quadrupole, 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, quadrupole, 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.

THPPD048	15+ T HTS Solenoid for Muon Accelerator Program	solenoid, laser, power-supply	3617
	Y. Shiroyanagi, R.C. Gupta, P.N. Joshi, H.G. Kirk, R.B. Palmer, S.R. Plate, W. Sampson, P. Wanderer BNL, Upton, Long Island, New York, USA D.B. Cline UCLA, Los Angeles, California, USA J. Kolonko, R.M. Scanlan, R.J. Weggel Particle Beam Lasers, Inc., Northridge, California, USA
	Funding: This work is supported by the U.S.Department of Energy under Contract No. DE-AC02-98CH10886 and SBIR contract DOE Grant Numbers DE-FG02-07ER84855 and DE-FG02- 08ER85037. This paper will present the construction and test results of a ~10 T insert coil solenoid which is part of a proposed ~35 T solenoid being developed under a series of SBIR contracts involving collaboration between Particle Beam Lasers (PBL) and Brookhaven National Laboratory. The solenoid has an inner diameter of 25 mm, outer diameter of ~95 mm and a length of ~70 mm. It consists of 14 single pancake coils made from 4 mm wide 2G HTS conductor from SuperPower Inc., co-wound with a 4 mm wide, 0.025 mm thick stainless steel tape. These are paired into 7 double pancake coils. Each double pancake coil has been individually tested at 77 K before assembly in a complete solenoid. The solenoid is nearly ready for a high field test at ~4K.

THPPD076	Evaluation of Components for the High Precision Inductive Adder for the CLIC Damping Rings	damping, kicker, emittance, luminosity	3692
	J. Holma, M.J. Barnes CERN, Geneva, Switzerland
	The CLIC study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC damping rings will produce, through synchrotron radiation, ultra-low emittance beam with high bunch charge, necessary for the luminosity performance of the collider. To limit the beam emittance blow-up due to oscillations, the pulse generators for the damping ring kickers must provide extremely flat, high-voltage pulses. The specifications for the extraction kickers of the CLIC damping rings are particularly demanding: the flattop of the output pulse must be 160 ns duration, 12.5 kV and 250 A, with a combined ripple and droop of not more than ±0.02 %. An inductive adder allows the use of different modulation techniques and is therefore a very promising approach to meeting the specifications. In addition to semiconductors working in their saturated region, semiconductors working in their linear region are needed for applying analogue modulation techniques. Simulations have been carried out to define component specifications for the inductive adder: this paper reports the results of tests and measurements of various components.

THPPP009	Automated Execution and Tracking of the LHC Commissioning Tests	status, controls, LabView, hadron	3743
	K. Fuchsberger, V. Baggiolini, M. Galetzka, R. Gorbonosov, M. Pojer, M. Solfaroli Camillocci, M. Zerlauth CERN, Geneva, Switzerland
	To ensure the correct operation and prevent system failures, which can lead to equipment damage in the worst case, all critical systems in the Large Hadron Collider (LHC), have to be tested thoroughly during dedicated commissioning phases after each intervention. In view of the around 7,000 individual tests to be performed each year after a Christmas stop, a lot of effort was already put into the automation of these tests at the beginning of LHC hardware commissioning in 2005, to assure the dependable execution and analysis of these tests. To further increase the productivity during the commissioning campaigns and to enforce amore consistent workflow, the development of a dedicated testing framework was launched. This new framework is designed to schedule and track the automated tests for all systems of the LHC and will also be extendable, e.g., to beam commissioning tests. This is achieved by re-using different, already existing execution frameworks. In this paper, we outline the motivation for this new framework and the related improvements in the commissioning process. Further, we sketch its design and present first experience from the re-commissioning campaign in early 2012.

THPPP027	The Design of a Large Booster Ring for the Medium Energy Electron-Ion Collider at JLab	booster, ion, dipole, electron	3791
	E.W. Nissen, T. Satogata, Y. Zhang JLAB, Newport News, Virginia, USA
	Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. In this paper, we present the current design of the large booster ring for the Medium Energy Electron-Ion Collder (MEIC) at JLab. The booster ring takes 3 GeV protons or ions of equivalent energy from a pre-booster ring, and accelerates them to 20 GeV for protons or equivalent energy for light to heavy ions before sending them to the ion collider ring. The present design calls for a figure-8 shape of the ring for superior preservation of ion polarization. The ring is made of warm magnets and shares a tunnel with the two collider rings. Acceleration is achieved by warm RF systems. A linear optics has been designed with the transition energy above the highest beam energy in the ring so crossing of transition energy will be avoided. Preliminary beam dynamics studies including chromaticity compensation, analyses of dynamic aperture, working point and high order effects are also presented in this paper.

THPPP090	Project X Functional Requirements Specification	linac, proton, factory, target	3945
	S.D. Holmes, S. Henderson, R.D. Kephart, J.S. Kerby, I. Kourbanis, V.A. Lebedev, C.S. Mishra, S. Nagaitsev, N. Solyak, R.S. Tschirhart Fermilab, Batavia, USA
	Funding: Work supported by the Fermi Research Alliance, under contract to the U.S. Department of Energy. Project X is a multi-megawatt proton facility being developed to support a world-leading program in Intensity Frontier physics at Fermilab. The facility is designed to support programs in elementary particle and nuclear physics, with possible applications to nuclear energy research. A Functional Requirements Specification has been developed in order to establish performance criteria for the Project X complex in support of these multiple missions, and to assure that the facility is designed with sufficient upgrade capability to provide U.S. leadership for many decades to come. This paper will describe the Functional Requirements for the Project X facility, their recent evolution, and the rationale for these requirements.

FRYCP01	Physics Results at the LHC and Implications for Future HEP Programmes	proton, luminosity, electron, linear-collider	4190
	R. Heuer CERN, Geneva, Switzerland
	This presentation should review the accumulated data of the TEVATRON and the first two years of LHC operation, highlighting major results and findings for high energy physics. This talk should highlight the most burning questions in high energy physics that emerged in light of these new results and discuss their implication for the planning and preparation of future accelerator projects.
	Slides FRYCP01 [14.536 MB]

Paper

Title

Other Keywords

Page

MOEPPB001

RF-breakdown Kicks at the CTF3 Two-beam Test Stand

linac, extraction, linear-collider, acceleration

73

A. Palaia, M. Jacewicz, T. Muranaka, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Farabolini
CEA/DSM/IRFU, France

The measurement of the effects of RF-breakdown on the beam in CLIC prototype accelerator structures is one of the key aspects of the CLIC two-beam acceleration scheme being addressed at the Two-beam Test Stand (TBTS) at CTF3. RF-breakdown can randomly cause energy loss and transverse kicks to the beam. Transverse kicks have been measured by means of a screen intercepting the beam after the accelerator structure. In correspondence of a RF-breakdown we detect a double beam spot which we interpret as a sudden change of the beam trajectory within a single beam pulse. To time-resolve such effect, the TBTS has been equipped with five inductive Beam Position Monitors (BPMs) and a spectrometer line to measure both relative changes of the beam trajectory and energy losses. Here we discuss the methodology used and we present the latest results of such measurements.

MOEPPB006

Formation of Beams in the Ion Accelerator Complex of the Medium Energy Electron Ion Collider Facility at JLab

ion, booster, proton, acceleration

88

S.L. Manikonda, P.N. Ostroumov
ANL, Argonne, USA
B. Erdelyi
Northern Illinois University, DeKalb, Illinois, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
At the interaction point of the Medium Energy Electron Ion Collider (MEIC) facility the luminosity of 10³³cm^-2s^-1 will be achieved through the collision of counter rotating beams of 0.5A ions and 3A electrons at 750MHz frequency. Formation of ion beams at MEIC is carried out in the Ion Accelerator Complex (IAC) comprising of a linac, pre-booster ring, booster ring, and a collider ring. We will describe the scheme proposed for the formation of ion beams at MEIC facility from the point of view of longitudinal beam dynamics. The proposed scheme minimizes losses due to space charge effects at low energies and needs moderate RF requirements already achieved at other existing facilities. Simulation studies have been conducted to verify the proposed scheme. We will present the results of these simulation studies.

MOEPPB008

Simulation of Hollow Electron Beam Collimation in the Fermilab Tevatron Collider

electron, simulation, collimation, quadrupole

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.

MOPPC016

Combined Ramp and Squeeze at the Large Hadron Collider

optics, injection, quadrupole, 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.

MOPPC034

Use of Helical Transport Channels for Bunch Recombination

simulation, luminosity, emittance, focusing

205

D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA
C.M. Ankenbrandt, C. Y. Yoshikawa
Muons, Inc, Batavia, USA

Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this paper we describe a new method for bunch recombination. We combine the high-chronicity of a helical transport channel (HTC) with the high-frequency bunching and phase-energy rotation concept (time-reversed) to obtain a compact bunch recombination system adapted to a muon collider scenario. We first present an idealized 1-D system with multiple chronicity transports. We then implement the concept in a single-chronicity channel, obtaining bunch recombination of 13 200MHz-spaced bunches to a single collider-ready bunch within a compact transport with modest rf requirements. That example is demonstrated within G4BL 3-D simulations. Variations and adaptations for different recombination requirements are discussed.

MOPPC037

Muon Collider Detector Backgrounds

background, electron, simulation, shielding

211

M.A.C. Cummings, S.A. Kahn
Muons, Inc, Batavia, USA
D. Hedin
Northern Illinois University, DeKalb, Illinois, USA
J.F. Kozminski
Lewis University, Romeoville, Illinois, USA

Funding: Supported in part by SBIR Grant 4738 · 10SC05447
Technological innovations in recent years have revived interest in muon colliders as the next generation energy frontier machine. Advances in muon cooling technology will make the focussing and acceleration of muons to TeV energies possible. The biggest challenge for muon colliders is that muons decay, but it is possible to build a large muon collider as a circular machine, even at multi-TeV energies, due to the greatly reduced synchrotron radiation expected from muons compared to electrons. The challenge for the detectors in such machines is overcoming the large backgrounds from muon decays in the colliding ring lattice that will inundate the interaction region (IR) and will make triggering and data reconstruction a challenge. Developing simulation tools that can reliably model the environment of the muon collider IR will be critical to physics analyses. We will need to expand the capabilities of current programs and use them to benchmark and verify results against each other. In this paper we will discuss these processes and calculate the resulting particle fluxes into the detector volume.

MOPPC038

Bethe-Heitler Muon Background at a Muon Collider

background, electron, hadron, simulation

214

S.A. Kahn, M.A.C. Cummings, T.J. Roberts
Muons, Inc, Batavia, USA
D. Hedin, A.O. Morris
Northern Illinois University, DeKalb, Illinois, USA
J.F. Kozminski
Lewis University, Romeoville, Illinois, USA

Multi-TeV muon colliders are an important option for a future energy frontier lepton collider since synchrotron radiation in a circular machine is significantly less than that in an electron collider. For a muon collider with 750 GeV μ+μ− with 2×10¹² μ per bunch we would expect 8.6×10⁵ muon decays per meter for the two beams. Muon decays are the source of beam induced backgrounds that can affect the physics. These backgrounds include electrons from muon decays, synchrotron radiation from the decay electrons, hadrons produced by photo-nuclear interactions, coherent and incoherent beam-beam pair production and Bethe-Heitler muon production. This paper will describe a simulation of the B-H muon pair production in a muon collider. These muons can penetrate the collider ring magnets and shielding and possibly enter into the detector regions. The simulation tracks B-H muons produced from electromagnetic shower interactions in collider ring material in the range of ±200 m from the interaction point.

MOPPC039

Electron Recombination in a Dense Hydrogen Plasma

cavity, electron, plasma, ion

217

B.T. Freemire, P.M. Hanlet
IIT, Chicago, Illinois, USA
M. Chung
Handong Global University, Pohang, Republic of Korea
M.G. Collura
Politecnico di Torino, Torino, Italy
M.R. Jana, C. Johnstone, T. Kobilarcik, G.M. Koizumi, M.A. Leonova, A. Moretti, M. Popovic, T.A. Schwarz, A.V. Tollestrup, Y. Torun, K. Yonehara
Fermilab, Batavia, USA
R.P. Johnson
Muons, Inc, Batavia, USA

Funding: US DOE under contract DE-AC02-07CH11359.
A high pressure hydrogen gas filled RF cavity was subjected to an intense proton beam to study the evolution of the beam induced plasma inside the cavity. The electron recombination rate with the dense ionized hydrogen plasma has been measured under varying conditions. Recombination rates as high as 10^-7 cm³/s have been recorded. This technique shows promise in the R&D program for a muon accelerator. The use of hydrogen, both as a way to prevent breakdown in an RF cavity and as a mechanism for cooling a beam of muons, will be discussed.

MOPPC041

Control of Beam Losses in the Front End for the Neutrino Factory

proton, target, factory, solenoid

223

C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
D.V. Neuffer
Fermilab, Batavia, USA
P. Snopok
IIT, Chicago, Illinois, USA

The Neutrino Factory produces neutrinos by muon decay in a storage ring. Pions are produced by firing high energy protons onto a target. Pions decay to muons, which are captured and accelerated to high energy. The target produces additionally a large background that is deposited in the muon capture front end and subsequent components. The implications of energy deposition in the front end lattice for the Neutrino Factory are addressed. Several approaches to mitigating the effect are proposed and discussed, including proton absorbers, chicane, and shielding.

MOPPC042

Higgs Boson Muon Collider Factory: h⁰, A, H Studies

factory, solenoid, simulation, dipole

226

D.B. Cline, X.P. Ding, J.L. Lederman
UCLA, Los Angeles, California, USA

With the recent hints of the Higgs boson from the LHC and a mass near 125 GeV/c we re-propose to study and build a muon collider Higgs factory to study the Higgs in the S channel. This was first proposed in 1992 by the first author. It is essential to study the Higgs boson for clues to new physics. The formation of the DOE MAP program, recent advances in 6D μ cooling methods, simulation, and targeting make this a feasible project to initiate at this time. This collider would fit into the FNAL site.

MOPPC044

Gallium as a Possible Target Material for a Muon Collider or Neutrino Factory

target, proton, factory, interaction-region

232

X.P. Ding
UCLA, Los Angeles, California, USA
J.S. Berg, H.G. Kirk, H. K. Sayed
BNL, Upton, Long Island, New York, USA
V.B. Graves
ORNL, Oak Ridge, Tennessee, USA
K.T. McDonald
PU, Princeton, New Jersey, USA
N. Souchlas, R.J. Weggel
Particle Beam Lasers, Inc., Northridge, California, USA

Funding: Work support by the U.S. Department of Energy in part under Awards No. DE-AC02-98CH10886 (BNL) and No. DF-FG02-92ER40695 (UCLA)
We consider the potential for a free-gallium-jet as an option for the pion-production target at a Muon Collider or Neutrino Factory. Advantages of such a target choice are its liquid state at relatively low temperature, its relatively efficient meson production, and its lower activation (compared to mercury). Using the MARS15 code, we have simulated particle production initiated by incoming protons with kinetic energies (KE) between 2 and 16~GeV. For each proton beam energy, we optimized the geometric parameters of the target: the radius of the liquid jet, the incoming proton beam angle, and the crossing angle between the jet and the proton beam. We compare the quantity of generated muons using a Ga target to that from a mercury jet target.

MOPPC083

LinguaFranca - A Graphical User Interface for Accelerator Modeling

simulation, quadrupole, lattice, optics

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.

MOPPC084

G4beamline Code Development

space-charge, electron, radiation, synchrotron

334

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

Funding: Supported in part by DoE STTR grant DE-FG02-06ER86281.
G4beamline is a single-particle-tracking simulation program based on Geant4, optimized specifically for beam lines. It is currently used by several hundred physicists and designers around the world, who apply it to a diverse set of interesting problems. As it includes particle decays and interactions, it is applicable to beams for which decays and interactions are important, such as modern muon facilities that involve ionization cooling. Its description language has been designed to be both versatile and user-friendly, and the program includes high-quality visualization and histogramming capabilities. This paper discusses recent code development and new features, and some interesting applications of the program. G4beamline is an open-source program freely available at http://g4beamline.muonsinc.com

MOPPD061

LHC@home: a Volunteer Computing System for Massive Numerical Simulations of Beam Dynamics and High Energy Physics Events

HOM, simulation, controls, superconducting-magnet

505

M. Giovannozzi, F. Grey, A. Harutyunyan, N. Hoimyr, P.L. Jones, A. Karneyeu, M.A. Marquina, E. McIntosh, B. Segal, P. Skands
CERN, Geneva, Switzerland
D. Lombraña González
CCC, 1211Geneva 23, Switzerland
L. Rivkin, I. Zacharov
EPFL, Lausanne, Switzerland

Recently, the LHC@home system has been revived at CERN. It is a volunteer computing system based on BOINC which allows boosting the available CPU-power in institutional computer centers by the help of individuals that donate the CPU-time of their PCs. Currently two projects are hosted on the system, namely SixTrack and Test4Theory. The first is aimed at performing beam dynamics simulations, while the latter deals with the simulation of high-energy events. In this paper the details of the global system, as well a discussion of the capabilities of either project will be presented. Milestones of progress of the projects will also be discussed.

MOPPD082

Recent T980 Crystal Collimation Studies at the Tevatron Exploiting a Pixel Detector System and a Multi-strip Crystal Array

collimation, proton, vacuum, scattering

559

D.A. Still, G. Annala, R.A. Carrigan, A.I. Drozhdin, T.R. Johnson, N.V. Mokhov, V. Previtali, R.A. Rivera, V.D. Shiltsev, J.R. Zagel, V.V. Zvoda
Fermilab, Batavia, USA
Y.A. Chesnokov, I.A. Yazynin
IHEP, Moscow Region, Russia
V. Guidi, A. Mazzolari
INFN-Ferrara, Ferrara, Italy
Yu.M. Ivanov
PNPI, Gatchina, Leningrad District, Russia
D. Mirarchi, S. Redaelli
CERN, Geneva, Switzerland

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy through the US LHC Accelerator Research Program (LARP).
With the shutdown of the Tevatron, the T-980 crystal collimation experiment at Fermilab has been successfully completed. Results of dedicated beam studies in May 2011 are described in this paper. For these studies, two multi-strip crystals were installed in the vertical goniometer. A two-plane CMS pixel detector was positioned upstream of the E03 collimator to image beam deflected by the crystals. This new enhanced hardware yielded impressive results. For the first time, a 980-GeV proton halo beam, channeled by an O-shaped crystal of the horizontal goniometer, was imaged using the pixel detector. The performance of this crystal, the first element of the collimation system, was very good. Reproducible results on the reduction of local beam losses were also obtained with an 8-strip crystal. For volume reflection these beam losses were measured with the PIN diodes and loss monitors at the E03 collimator. The long range beam losses for the channeled beam were observed using the F17 collimator one third of the ring downstream of the crystal. The measured channeling efficiency of the O-shaped crystal and the volume reflection efficiency of the 8-strip crystal were both ~70%.

MOPPR065

A Low-latency Sub-micron Resolution Stripline Beam Position Monitoring System for Single-pass Beamlines

monitoring, feedback, linear-collider, extraction

933

P. Burrows, D.R. Bett, N. Blaskovic Kraljevic, G.B. Christian, M.R. Davis, A. Gerbershagen, C. Perry
JAI, Oxford, United Kingdom
R. Apsimon, B. Constance
CERN, Geneva, Switzerland
J. Resta-López
IFIC, Valencia, Spain

A low-latency, sub-micron resolution stripline beam position monitoring system has been developed for use in single-pass beamlines. The fast analogue front-end signal processor is based on a single-stage RF down-mixer and is combined with an FPGA-based system for digitisation and further signal processing. The system has been deployed and tested with beam at the Accelerator Test Facility at KEK. Performance results are presented on the calibration, resolution and stability of the system. A detailed simulation has been developed that is able to account for the measured performance.

TUYA01

Research and Development of Future Muon Collider

cavity, plasma, proton, emittance

1020

K. Yonehara
Fermilab, Batavia, USA

A muon collider would provide a unique facility for future elementary-particle physics research, and present unique challenges for accelerator physics and technology. An R&D effort is underway to address major challenges in the design of a future muon collider. This talk should provide an opportunity to discuss the muon collider's challenges, present recent R&D results, and describe future prospects.

TUYA02

Overview of Asymmetric Electron Hadron Colliders

electron, ion, hadron, proton

1025

V. Ptitsyn
BNL, Upton, Long Island, New York, USA

The first lepton-proton collider HERA at DESY completed its operation in 2007. Presently, several accelerator proposals for future electron-hadron colliders are under consideration in several laboratories from all over the world. The future accelerators intend to exceed the HERA luminosity by 2-3 orders of magnitude, as well as to cover the different ranges of center-of-mass collision energies. The research capabilities will be extended by including the collisions of electrons with heavy ions, as well as, in some designs, with polarized protons and polarized ions. The future electron-hadron colliders would serve as high-resolution microscopes able to reveal unprecedented details of the structure of nucleons and ions, including their spin content and the state of high gluon density matter. The colliders will provide us with ultimate tools to test both the ways Quantum Chromodynamics works as well as to look for new physics beyond the Standard Model. All proposed electron-hadron colliders are based on the extension of existing accelerators to accommodate the electron-hadron collisions. Advanced accelerator technologies are utilized in order to achieve the desired high luminosity.

Slides TUYA02 [6.002 MB]

TUOAA03

Tests of Low Emittance Tuning Techniques at SLS and DAΦNE

quadrupole, emittance, coupling, alignment

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]

TUEPPB001

Interaction of Muon Beam with Plasma Developed During Ionization Cooling

plasma, wakefield, electron, simulation

1110

S. Ahmed
JLAB, Newport News, Virginia, USA
K.B. Beard, T.J. Roberts
Muons, Inc, Batavia, USA
D.M. Kaplan, L.K. Spentzouris
Illinois Institute of Technology, Chicago, Illinois, USA

Muon collider has been envisioned as a future high energy lepton machine. High luminosity can be obtained by the ionization cooling – best suited for muons due to their short life time. In this cooling process, particles ionize material medium in which they lose momentum, thus the normalized emittance is reduced. The ionized medium is called plasma and the ionization density could increase due to the passage of multiple bunches through the material. This means that the incoming beams interact with plasma together with ionizing the medium used for cooling. It is, therefore, important to investigate the effects of background plasma on the incoming bunches. A comprehensive studies of muon beam propagation through plasma medium using EM particle-in-cell simulations. This computational study involves kinetic model, therefore, provides deep insight of the phenomena, which cannot be obtained by the conventional fluid model. The wakes excited by mu+ and mu- are different due to the beam polarity and depends on their relative densities. Externally applied axial magnetic field suppresses the wakes evolved during the interaction. The details of this study will be discussed in the paper.

TUEPPB002

Numerical Simulations of Transverse Beam Diffusion Enhancement by the Use of Electron Lens in the Tevatron Collider

electron, simulation, resonance, beam-beam-effects

1113

V. Previtali, G. Stancari, 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)."
Transverse beam diffusion for the Tevatron machine has been calculated using the Lifetrac code. The following effects were included: random noise (representing residual gas scattering, voltage noise in the accelerating cavities) lattice nonlinearities and beam-beam interactions. The time evolution of particle distributions with different initial amplitudes in Hamiltonian action has been simulated for 6 million turns, corresponding to a machine time of about 2 minutes. For each particle distribution, several cases have been considered: a single beam in storage ring mode, the collider case, and the effects of a hollow electron beam collimator

TUPPC041

A 3 TeV Muon Collider Lattice Design

quadrupole, emittance, lattice, dipole

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

TUPPC078

Proposal of an Inverse Logarithm Scaling Law for the Luminosity Evolution

luminosity, emittance, dynamic-aperture, hadron

1353

M. Giovannozzi
CERN, Geneva, Switzerland
C.H. Yu
IHEP, Beijing, People's Republic of China

A scaling law for the time-dependence of the dynamic aperture, i.e., the region of phase space where stable motion occurs, was proposed in previous papers, about ten years ago. It was showed that dynamic aperture has a logarithmic dependence on time, which would be suggested by some fundamental theorems of the theory of dynamical systems. Such a scaling law was recently extended also to the intensity evolution in a storage ring. In this paper, inspired by these results, and inverse logarithm scaling law for the luminosity in a circular collider is proposed. The law is then tested against the data from the LHC physics runs and also with some examples from other machines. The results are presented and discussed in details.

TUPPC097

Computational Modeling of Electron Cloud For MEIC

electron, simulation, ion, emittance

1383

S. Ahmed, J.D. Dolph, G.A. Krafft, T. Satogata, B.C. Yunn
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
This work is the continuation of our earlier studies on electron cloud (EC) simulations reported in IPAC'11 for the medium energy electron-ion collider (MEIC) envisioned at JLab beyond the 12 GeV upgrade of CEBAF. In this paper, we will study the EC saturation density in various MEIC operations scenarios to calculate details of the EC-induced wakefield to establish more stringent bounds on instability thresholds and determine whether EC mitigation, such as NEG coatings or solenoid fields, should be considered in the MEIC design.

TUPPC099

Optimization of Chromaticity Compensation and Dynamic Aperture in MEIC Collider Rings

sextupole, ion, dynamic-aperture, octupole

1389

F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang
JLAB, Newport News, Virginia, USA
K.B. Beard
Muons, Inc, Batavia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by US DOE STTR grant DE-SC0006272.
The conceptual design of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab relies on an ultra-small beta-star to achieve high luminosities of up to 10³⁴ cm^-2s⁻¹. A low-beta insertion for interaction regions unavoidably induces large chromatic effects that demand a proper compensation. The present approach of chromatic compensation in the MEIC collider rings is based on a local correction scheme using two symmetric chromatic compensation blocks that includes families of sextupoles, and are placed in a beam extension area on both sides of a collision point. It can simultaneously compensate the first order chromaticity and chromatic beam smear at the IP without inducing significant second order aberrations. In this paper, we investigate both the momentum acceptance and dynamic aperture in the MEIC ion collider ring by considering the aberration effects up to the third order, such as amplitude dependent tune shift. We also explore the compensation of the third order effects by introducing families of octupoles in the extended beam area.
Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by US DOE STTR grant DE-SC0006272.

TUPPC102

Simulation Study of Beam-beam Effects in Ion Beams with Large Space Charge Tuneshift

space-charge, simulation, lattice, synchrotron

1398

C. Montag
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.
During low-energy operations with gold-gold collisions at 3.85 GeV beam energy, significant beam lifetime reductions have been observed due to the beam-beam interaction in the presence of large space charge tuneshifts. These beam-beam tuneshift parameters were about an order of magnitude smaller than during regular high energy operations. To get a better understanding of this effect, simulations have been performed. Recent results are presented.

TUPPD010

Helical Muon Beam Cooling Channel Engineering Design

cavity, solenoid, simulation, beam-cooling

1425

G. Flanagan, R.P. Johnson, G.M. Kazakevich, F. Marhauser, M.L. Neubauer
Muons, Inc, Batavia, USA
V.S. Kashikhin, M.L. Lopes, G.V. Romanov, M.A. Tartaglia, K. Yonehara, M. Yu, A.V. Zlobin
Fermilab, Batavia, USA

Funding: Supported in part by DOE STTR Grant DE-SC0006266
The Helical Cooling Channel (HCC), a novel technique for six-dimensional (6D) ionization cooling of muon beams, has shown considerable promise based on analytic and simulation studies. However, the implementation of this revolutionary method of muon cooling requires new techniques for the integration of hydrogen-pressurized, high-power RF cavities into the low-temperature superconducting magnets of the HCC. We present the progress toward a conceptual design for the integration of 805 MHz RF cavities into a 10 T Nb3Sn based HCC test section. We include discussions on the pressure and thermal barriers needed within the cryostat to maintain operation of the magnet at 4.2 K while operating the RF and energy absorber at a higher temperature. Additionally, we include progress on the Nb3Sn helical solenoid design

TUPPD011

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

simulation, resonance, emittance, quadrupole

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.

TUPPD012

Complete Muon Cooling Channel Design and Simulations

emittance, dipole, simulation, solenoid

1431

C. Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson
Muons, Inc, Batavia, USA
Y.S. Derbenev, V.S. Morozov
JLAB, Newport News, Virginia, USA
D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA

Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittances required for an energy-frontier muon collider. However, it has not yet been demonstrated that the various proposed cooling subsystems can be consolidated into an integrated end-to-end design. Presented here are concepts to address the matching of transverse emittances between subsystems through an extension of the theoretical framework of the Helical Cooling Channel (HCC), which allows a general analytical approach to guide the transition from one set of cooling channel parameters to another.

TUPPD013

Bunch Coalescing in a Helical Channel

acceleration, emittance, simulation, factory

1434

C. Y. Yoshikawa, C.M. Ankenbrandt
Muons, Inc, Batavia, USA
D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA

Funding: Supported in part by SBIR Grant 4725 · 09SC02739.
A high-luminosity Muon Collider requires bunch recombination for optimal luminosity. In this paper, we take advantage of the large slip factor in a helical transport channel (HTC) to coalesce bunches of muons into a single one over a shorter distance than can be achieved over a straight channel. The coalescing subsystem that is designed to merge 9 bunches has a horizontal length of ~105m and is able to achieve efficiencies of 99.7%, 98.4%, and 94.2% for 9, 11, and 13 bunches, respectively, where each bunch has emittances expected at the end of an HCC. Simplified designs incorporating fill factors for RF cavities of ~25% and ~50% obtained efficiencies of 96%, 94-95%, and 90-91% for 9, 11, and 13 bunches, respectively. The efficiencies above do not include decay losses, which would be ~8% for muons with kinetic energy of 200 MeV.

TUPPP092

Renovated Two-stage Bunch Compressor for the International Linear Collider

wiggler, positron, linac, linear-collider

1801

S. Seletskiy
BNL, Upton, Long Island, New York, USA
N. Solyak
Fermilab, Batavia, USA

The International Linear Collider (ILC) utilizes a Bunch Compressor (BC) in the Damping Ring to Main Linac Transfer Line (RTML) that compresses the RMS bunch length from 6 mm to 300 micrometers before sending the beam to the Main Linac. It was decided to utilize a two stage BC for the design baseline, since it provides an additional option for the ILC to work with 150 micrometers long bunches and reduces the energy spread at the RTML exit under normal operational conditions. In this paper we report the new design of the optimized two-stage bunch compressor.

TUPPR008

One 233 km Tunnel for Three Rings: e⁺e^-, p-pbar, and μ⁺+μ⁻

dipole, emittance, luminosity, lattice

1828

G.T. Lyons, L.M. Cremaldi, A. Datta, M. Duraisamy, T.H. Luo, D.J. Summers
UMiss, University, Mississippi, USA

Funding: Supported by DE-FG05-91ER40622
In 2001, a cost analysis was conducted to build a 233 km circumference tunnel in northern Illinois for a Very Large Hadron Collider (VLHC). Here we outline the implementations of e⁺e⁻, proton anti-proton, and μ⁺+ μ⁻ collider rings in such a tunnel using recent technological innovations. The 500 GeV e⁺e⁻ collider employs a Crab Waist Crossing, ultra low emittance damped bunches, a vertical IP focal length of 0.06 cm, 12 GV of superconducting RF, and 0.026 Tesla low coercivity, grain oriented silicon steel/concrete dipoles. The 40 TeV proton anti-proton collider uses the high intensity Fermilab anti-proton source, exploits high cross sections for proton anti-proton production of high mass states, and uses 2 Tesla 0.005% ultra low carbon steel/YBCO superconductor magnets run with liquid neon. The 40 TeV muon ring ramps the 2 Tesla superconducting magnets at 8 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 2 to 20 TeV in 72 orbits with 72% survival, and mitigates neutrino radiation with a phase shifting, roller coaster FODO lattice.*
* G. T. Lyons, http://arxiv.org/pdf/1112.1105

TUPPR011

Six-dimensional Bunch Merging for Muon Collider Cooling

emittance, simulation, kicker, solenoid

1831

R.B. Palmer, R.C. Fernow
BNL, Upton, Long Island, New York, USA
D.V. Neuffer
Fermilab, Batavia, USA

Funding: Work supported by US Department of Energy under contracts DE-AC02-98CH10886 and DE-AC02-07CH11359.
Muons for a Muon Collider are diffusely produced from pion decay. They are first phase rotated into a trains of bunches. The trains are ionization cooled in all six dimensions until they can be merged into single bunches, one of each sign. They are then further cooled in six dimensions before acceleration and injection into the collider. This merging matches more efficiently into the second phase of cooling if the merging is also in six dimensions. A scheme to do this is proposed. Groups of 3, of the initial 12, bunches are merged longitudinally into 4 longer bunches, using rf with multiple harmonics. These 4 are then kicked into 4 separate (trombone) channels of different lengths to bring them to closely packed transverse locations at the same time. Here they are captured into a single bunch with now increased transverse emittance.

TUPPR013

Design Integration and Vision Sharing for the ILC

lattice, linear-collider, linac, damping

1837

B. List, L. Hagge, S. Sühl, N.J. Walker, N. Welle
DESY, Hamburg, Germany

The Global Design Effort for the International Linear Collider is currently preparing the Technical Design Report, which will be released in early 2013. The starting point of a consistent and correct design is the accelerator lattice, which defines the layout of the machine. Integrating the lattice geometrically and optically provides the basis for civil engineering and conventional facilities planning and finally the cost estimate. Tools that provide three-dimensional visualization of the lattice and tunnel help to perform the design integration and allow sharing a common vision of the final accelerator. We will present the process that was established to arrive at such an integrated design and the tools that were developed to support that process by analyzing and visualizing lattice files.

TUPPR022

Traditional Final Focus System for CLIC

luminosity, lattice, linear-collider, quadrupole

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.

TUPPR024

CLIC Recombination Scheme for the Low Energy Operation Mode

factory, acceleration, luminosity, linac

1864

A. Gerbershagen, D. Schulte
CERN, Geneva, Switzerland
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

The CLIC recombination scheme is a concept of multiplication of the drive beam frequency in order to generate a 12 GHz RF wave for the main beam acceleration. CLIC is designed to be operated in nominal and in low energy modes. The low energy operation modes require the train length to be increased by different factors in order to maintain the same level of luminosity. Also the number of initial trains that are merged to form each final train is changed. The combination scheme must be able to accommodate and recombine both long and short trains for nominal and low energy CLIC operation modes. The recombination hence becomes a non-trivial process and makes the correction of the errors in the drive beam more challenging. The present paper describes in detail the recombination process and its consequences.

TUPPR048

Short RF Pulse Linear Collider

linac, linear-collider, klystron, wakefield

1924

C.-J. Jing, S.P. Antipov, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, W. Gai, J.G. Power
ANL, Argonne, USA

Funding: DOE SBIR program under Contractor #DE-SC0004320
In general, a high gradient is desirable for future linear collider designs because it can reduce the total linac length. More importantly, the efficiency and the cost to sustain the high gradient should also be considered in the optimization process of an overall design. In this article, we explore a parametric territory of short rf pulse, high group velocity, high frequency, and high gradient, etc., that may lead to an affordable high energy linear collider in the future.

TUPPR076

The LHeC Project Development Beyond 2012

electron, linac, cavity, dipole

1999

F. Zimmermann, O.S. Brüning
CERN, Geneva, Switzerland
M. Klein
The University of Liverpool, Liverpool, United Kingdom

The LHeC study group is finalizing a Conceptual Design Report for publication early in 2012. This paper discusses the next steps required for developing a Technical Design Report and highlights the R&D developments, test facilities and implementation studies that need to be addressed over the coming years. Particular emphasize will be given to similarities with other ongoing accelerator and detector studies, and to a discussion of possible international collaboration efforts.

TUPPR077

Simulation Studies for the LHC Long-Range Beam-Beam Compensators

optics, simulation, resonance, betatron

2002

T.L. Rijoff, R.J. Steinhagen, F. Zimmermann
CERN, Geneva, Switzerland

The LHC performance and the minimum crossing angle are limited by long-range beam-beam collisions. Wire compensators can mitigate part of the long-range effects and may allow for smaller crossing angles, smaller β^*, or higher beam intensity. A prototype long-range wire compensator should be installed in the LHC by 2014/15. We report simulation studies examining and comparing the efficiency of the wire compensation, in terms of tune footprint or dynamic aperture, at various candidate locations, with different wire shapes, and for varying transverse distance from the beam.

TUPPR078

LEP3: A High Luminosity e⁺e⁻ Collider in the LHC Tunnel to Study the Higgs Boson

luminosity, positron, emittance, synchrotron

2005

F. Zimmermann, M. Koratzinos
CERN, Geneva, Switzerland
A.P. Blondel
DPNC, Genève, Switzerland
M. Zanetti
MIT, Cambridge, Massachusetts, USA

Recent indications from two LHC experiments suggest that the Higgs boson might be light, within the mass range 115-130 GeV. Such object could be studied at an e⁺e⁻ collider with about 240 GeV centre-of-mass energy. A corresponding Higgs factory – “LEP3” - could be installed in the LHC tunnel, reducing its cost and also allowing for a second life of the two LHC general-purpose detectors. We present preliminary accelerator and beam parameters for LEP3 tailored so as to provide a peak luminosity of 10³⁴/cm²/s at each of two experiments, while respecting a number of constraints including beamstrahlung limits. At this luminosity around 20,000 Higgs events per year per experiment could be obtained for a Standard Model Higgs boson with a mass of 115-130 GeV. For the parameters considered the estimated luminosity lifetime is about 12 minutes, and the synchrotron radiation losses are 50 MW per beam. High operational efficiency requires two rings: a low emittance collider storage ring operating at constant energy, and a separate accelerator to top up the colliding beams every few minutes. The alternative of a larger ring collider installed in a new, bigger tunnel will also be discussed.

TUPPR079

Ion Polarization in the MEIC Figure-8 Ion Collider Ring

polarization, ion, proton, resonance

2008

V.S. Morozov, Y.S. Derbenev, Y. Zhang
JLAB, Newport News, Virginia, USA
P. Chevtsov
Paul Scherrer Institut, Villigen, Switzerland
Y. Filatov
MIPT, Dolgoprudniy, Moscow Region, Russia
A.M. Kondratenko, M.A. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The nuclear physics program envisaged at the Medium-energy Electron-Ion Collider (MEIC) currently being developed at the Jefferson Lab calls for collisions of 3-11 GeV/c longitudinally polarized electrons and 20-100 GeV/c, in equivalent proton momentum, longitudinally or transversely polarized light ions. In this paper, we present a scheme based on figure-8 shaped booster and collider rings that provides the required ion polarization arrangement in the MEIC's ion collider ring.
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.

TUPPR082

MEIC Design Progress

ion, electron, booster, polarization

2014

Y. Zhang, Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, R. Li, F. Lin, V.S. Morozov, E.W. Nissen, F.C. Pilat, T. Satogata, C. Tennant, B. Terzić, B.C. Yunn
JLAB, Newport News, Virginia, USA
D.P. Barber
DESY, Hamburg, Germany
Y. Filatov
JINR, Dubna, Russia
C. Hyde
Old Dominion University, Norfolk, Virginia, USA
A.M. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia
S.L. Manikonda, P.N. Ostroumov
ANL, Argonne, USA
M.K. Sullivan
SLAC, Menlo Park, California, USA

Funding: Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and No. DE-AC02-06CH11357.
This paper will report the recent progress in the conceptual design of MEIC, a high luminosity medium energy polarized ring-ring electron-ion collider at Jefferson lab. The topics and achievements that will be covered are design of the ion large booster and the ERL-circulator-ring-based electron cooling facility, optimization of chromatic corrections and dynamic aperture studies, schemes and tracking simulations of lepton and ion polarization in the figure-8 collider ring, and the beam-beam and electron cooling simulations. A proposal of a test facility for the MEIC electron cooler will also be discussed.

TUPPR097

Modeling and Simulation of LHC Beam-Based Collimator Setup

alignment, beam-losses, simulation, emittance

2059

G. Valentino, N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta
R.W. Assmann, F. Burkart, S. Redaelli, A. Rossi, D. Wollmann
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain

In the 2011 Large Hadron Collider run, collimators were aligned for proton and heavy ion beams using a semi-automatic setup algorithm. The algorithm provided a reduction in the beam time required for setup, an elimination of beam dumps during setup and higher accuracy with respect to manual alignment. A collimator setup simulator was developed based on a Gaussian model of the beam distribution as well as a parametric model of the beam losses. A time-varying beam loss signal can be simulated for a given collimator movement into the beam. The simulation results and comparison to measurement data obtained during collimator setups and dedicated fills for beam halo scraping are presented. The simulator will then be used to develop a fully automatic collimator alignment algorithm.

TUPPR098

Comparison of LHC Collimator Beam-Based Alignment Centers to BPM-Interpolated Centers

alignment, injection, hadron, collimation

2062

G. Valentino, N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta
R.W. Assmann, R. Bruce, G.J. Müller, S. Redaelli, A. Rossi, G. Valentino
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain

The beam centers at the Large Hadron Collider collimators are determined by beam-based alignment, where both jaws of a collimator are moved in separately until a loss spike is detected on a Beam Loss Monitor downstream. Orbit drifts of more than a few hundred micrometers cannot be tolerated, as they would reduce the efficiency of the collimation system. Beam Position Monitors (BPMs) are installed at various locations around the LHC ring, and a linear interpolation of the orbit can be obtained at the collimator positions. In this paper, the results obtained from beam-based alignment are compared with the orbit interpolated from the BPM data throughout the 2011 LHC proton run. The stability of the orbit determined by collimator alignment during the run is evaluated.

WEXA01

The High Intensity Horizon at Fermilab

proton, kaon, superconducting-RF, linac

2065

R.S. Tschirhart
Fermilab, Batavia, USA

Fermilab’s high intensity horizon is “Project-X” which is a US led initiative with strong international participation that aims to realize a next generation proton source that will dramatically extend the reach of Intensity Frontier research. The Project-X research program includes world leading sensitivity in long-baseline and short-baseline neutrino experiments, a rich program of ultra-rare muon and kaon decays, opportunities for next-generation electric dipole moment experiments and other nuclear/particle physics probes, and a platform to investigate technologies for next generation energy applications. A wide range of R&D activities has been started to support mission critical accelerator subsystems, such as high-gradient superconducting RF accelerating structures, efficient RF power systems, cryo-modules and cryogenic refrigeration plants, advanced beam diagnostics and instrumentation, high-power targetry, as well as the related infrastructure and civil construction preparing for a construction start as early as 2017. The status and prospects of developing the accelerator design, research program, and associated collaborations will be presented.
* The Project X program spans several Sub Classifications: A08, A14 A17, A21, A28.

Slides WEXA01 [9.216 MB]

WEYA03

Overview of B-Factories

emittance, sextupole, injection, quadrupole

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]

WEXB03

Protecting Accelerator Control Systems in the Face of Sophisticated Cyber Attacks

controls, target, monitoring, neutron

2101

S.M. Hartman
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725
Recent events at ORNL and the knowledge of the use of the STUXNET virus in another country illustrate the vulnerability of advanced control systems to increasingly intelligent cyber attacks. The threat is clearly evolving and escalating, and techniques for mitigation are clearly of interest to the broader accelerator community. Risks associated with remote access must be balanced against operational efficiency and operating models. This talk should review the ongoing evolution of system architecture and security that permit effective facility operation while protecting against such harmful intrusions.

Slides WEXB03 [6.747 MB]

WEOBA03

Beam Tests of a High Pressure Gas-Filled Cavity for a Muon Collider

cavity, electron, ion, pick-up

2131

T.A. Schwarz, M.A. Leonova, A. Moretti, M. Popovic, A.V. Tollestrup, K. Yonehara
Fermilab, Batavia, USA
M. Chung
Handong Global University, Pohang, Republic of Korea
B.T. Freemire, P.M. Hanlet, Y. Torun
IIT, Chicago, Illinois, USA
R.P. Johnson
Muons, Inc, Batavia, USA

Funding: US DOE under contract DE-AC02-07CH11359.
One of the greatest challenges in constructing a Muon Collider is cooling the hot muons into a focused beam after their production. Because the beam must be cooled quickly before the muons decay, compact cooling designs require high gradient cavities inside strong magnetic fields. Unfortunately, due to focused field emission, an external magnetic field degrades the performance of the cavity below what is required for a muon collider. High-pressure gas inside the cavity has been proposed to both mitigate this effect, as well as serve as an absorber for transversely cooling the muon beam. A prototype of a high pressure gas-filled cavity is currently being studied at the Muon Test Area at Fermilab. The experimental setup as well as several measurements of the physics and performance of the apparatus while operating in a 400-MeV proton beam will be discussed.

Slides WEOBA03 [6.912 MB]

WEPPC007

Image Processing for Characterization of Surfaces of Superconducting RF Cavities

cavity, superconductivity, LabView, linear-collider

2218

M. Wenskat, S. Aderhold, E. Elsen, S. Karstensen, F. Schlander, L. Steder
DESY, Hamburg, Germany

Funding: ILC HiGrade
Optical inspection of finished Nb superconducting RF cavities has worldwide been established as an important tool for identification of field limiting surface features. Single defects in a single cell of a 9-cell cavity may severely constrain the maximum gradient while the micro-structure in the vicinity of a welding seam could affect the quench behavior. DESY has automated the imaging of critical cavity surface areas, in particular those of high magnetic field. With resolution of ~10 μm2 the information volume is large and the systematic examination becomes a necessity. The development of image processing algorithms has been started with two goals: automatic characterization of cavity surface properties and defect detection. The former results aid the quality assessment of cavities after manufacture; the latter serves to push the gradient performance. The status and prospects of the image processing for the European XFEL and ILC will be presented.

WEPPC033

RF and Surface Properties of Bulk Niobium and Niobium Film Samples

niobium, electron, quadrupole, 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.

WEPPC054

Resonance Excitation of Longitudinal High Order Modes in Project X Linac

HOM, linac, factory, kaon

2336

A.I. Sukhanov, M.H. Awida, I.V. Gonin, T.N. Khabiboulline, A. Lunin, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, USA

Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.

WEPPC085

Engineering of a Superconducting 400 MHz Crabbing Cavity for the LHC HiLumi Upgrade

cavity, luminosity, niobium, SRF

2411

D. Gorelov, T.L. Grimm
Niowave, Inc., Lansing, Michigan, USA
S.U. De Silva, J.R. Delayen
ODU, Norfolk, Virginia, USA

Funding: This work is supported by the US DOE-HEP SBIR/STTR program and the US DOE through the US LHC Accelerator Research Program (LARP).
The recently developed new simplified design for the 400 MHz LHC crabbing cavity presents attractive properties compared to conventional designs. The proposed approach can be equally compact in both transverse dimensions and allows horizontal as well as vertical deflection of the beam in the collider. The significant modification of the parallel-bar design with the bars merged to the side walls of the cavity gives improved properties, such as better mode separation and reduced surface fields*. A transverse deflecting voltage of 3 to 5 MV in a single cavity can be expected with the peak surface electric field lower then 50 MV/m and peak magnetic field below 100 mT. This paper presents engineering issues of the proof-of-concept crabbing cavity design and discusses the manufacturing techniques. The paper discusses present status of the project including fabrication of the niobium cavity, as well as room temperature and cryogenic testing.
* J.R. Delayen, S.U. De Silva, "Design of Superconducting Parallel-Bar Deflecting/Crabbing Cavities with Improved Properties," Proc. of 2011 PAC, New York, NY, USA, 2011, p. 10²¹.

WEPPC112

Development of a Fundamental Power Coupler for High-Current Superconducting RF Cavity

simulation, cavity, linac, electron

2483

P. Jain
Stony Brook University, Stony Brook, USA
S.A. Belomestnykh, I. Ben-Zvi, W. Xu
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. DOE and by the DOE grant DE-SC0002496 to Stony Brook University.
Brookhaven National Laboratory has undertaken a project to design a five-cell superconducting 703.75 MHz RF cavity for the Energy Recovery Linac (ERL) and the planned RHIC electron cooler. The earlier developed cavity, viz., the BNL1 is fed by a klystron using a co-axial Fundamental Power Coupler (FPC), which delivers 50 kW of cw RF power to the cavity. During the cavity operation, it has been observed that a 5 K cooling line intercept in the FPC introduces undesirable microphonics. A modification in the existing FPC has been planned to determine the feasibility of getting rid of the 5 K cooling line. The modified coupler will be incorporated in the newly designed, under construction BNL3 cavity. In order to accommodate this modification, peak microphonics of 12 Hz and 20 kW of cw RF power will be considered. This paper describes the design of the new FPC starting from the analysis of thermal profile along its length from first principles.

WEPPD027

Global and Local Loss Suppression in the UA9 Crystal Collimation Experiment

collimation, ion, proton, simulation

2561

W. Scandale
LAL, Orsay, France
S. Montesano
CERN, Geneva, Switzerland

UA9 was operated in the CERN-SPS for some years in view of investigating the feasibility of the halo collimation assisted by bent crystals. Two-millimeter-long silicon crystals, with bending angles of about 150 mirrored, are used as primary collimators. The crystal collimation process is obtained consistently through channeling with high efficiency. The loss profiles in the area of the crystal-collimator setup and in the downstream dispersion suppressor area show a steady reduction of slightly less than one order of magnitude at the onset of the channeling process. This result holds both for protons and for lead-ions. The corresponding loss map in the accelerator ring is accordingly reduced. These observations strongly support our expectation that the coherent deflection of the beam halo by a bent crystal should enhance the collimation efficiency in hadron colliders, such as LHC.
for the UA9 Collaboration

WEPPD036

Energy Flow and Deposition in a 4-MW Muon Collider Target System

target, shielding, radiation, factory

2588

N. Souchlas, R.J. Weggel
Particle Beam Lasers, Inc., Northridge, California, USA
X.P. Ding
UCLA, Los Angeles, California, USA
V.B. Graves
ORNL, Oak Ridge, Tennessee, USA
H.G. Kirk, H. K. Sayed
BNL, Upton, Long Island, New York, USA
K.T. McDonald
PU, Princeton, New Jersey, USA

Funding: Work support by the U.S. Department of Energy in part under Award No. DE-AC02-98CH10886
The design of the target station for a 4-MW Muon Collider or a Neutrino Factory is evolving to include more space for services to the magnets and internal tungsten shielding, as well as consideration of removing the 5-T resistive copper coils, thereby reducing the peak field from 20 to 15 T. Simulations with MARS15 have been performed to verify that these revisions preserve sufficient shielding that the peak power deposition everywhere in the superconducting magnets will be less than 0.1 mW/g, permitting at least a 10-year operational lifetime against radiation damage to the organic insulators.

WEPPD037

Shielding of Superconducting Coils for a 4-MW Muon-Collider Target System

shielding, target, interaction-region, factory

2591

R.J. Weggel, N. Souchlas
Particle Beam Lasers, Inc., Northridge, California, USA
X.P. Ding
UCLA, Los Angeles, California, USA
V.B. Graves
ORNL, Oak Ridge, Tennessee, USA
H.G. Kirk, H. K. Sayed
BNL, Upton, Long Island, New York, USA
K.T. McDonald
PU, Princeton, New Jersey, USA

Funding: Work support by the U.S. Department of Energy in part under Award No. DE-AC02-98CH10886
The target system envisioned for a Muon Collider/Neutrino Factory features a liquid Hg jet target immersed in a 20-T solenoidal field. Field quality limits intercoil gaps to ~ 40% of the O.D. of the flanking coils. Longitudinal sag of the tungsten shielding vessels limits their length to ~ 7 m. Support members adequate to resist intercryostat axial forces require an aggregate cross section of ~ 0.1 m²; the cryogenic heat leakage may be large. The innermost shielding vessel wall can be adequately cooled by helium gas only if its pressure is ~ 10 atm and its velocity is ~ 200m/s. However, the analysis in this paper found none of these engineering challenges to be insurmountable.

WEPPD038

Mercury Handling for the Target System for a Muon Collider

target, shielding, proton, factory

2594

V.B. Graves
ORNL, Oak Ridge, Tennessee, USA
X.P. Ding
UCLA, Los Angeles, California, USA
H.G. Kirk, H. K. Sayed
BNL, Upton, Long Island, New York, USA
K.T. McDonald
PU, Princeton, New Jersey, USA
N. Souchlas, R.J. Weggel
Particle Beam Lasers, Inc., Northridge, California, USA

Funding: Work supported in part by US DOE Contract NO.~DE-AC02-98CHI10886 and DE-AC05-00OR22725.
The baseline target concept for a Muon Collider or Neutrino Factory is a free-stream mercury jet within a 20-T magnetic field being impacted by an 8-GeV proton beam. A pool of mercury serves as a receiving reservoir for the mercury and a dump for the unexpended proton beam. Design issues discussed in this paper include the nozzle, splash mitigation in the mercury pool, the mercury containment vessel, and the mercury recirculation system.

WEPPD074

Issues and Feasibility Demonstration of Positioning Closed Loop Control for the CLIC Supporting System Using a Test Mock-up with Five Degrees of Freedom

alignment, controls, feedback, linear-collider

2696

M. Sosin, M. Anastasopoulos, N. Chritin, J. Kemppinen, H. Mainaud Durand, V. Rude, G. Sterbini, S. griffet
CERN, Geneva, Switzerland

Since several years, CERN is studying the feasibility of building a high energy e⁺ e⁻ linear collider: the CLIC (Compact LInear Collider). One of the challenges of such a collider is the pre-alignment precision and accuracy requirement on the transverse positions of the linac components, which is typically 14 μm over a window of 200 m. To ensure the possibility of positioning within such tight constraints, CERN Beams Department’s Survey team has worked intensively at developing the methods and technology needed to achieve that objective. This paper describes activities which were performed on a test bench (mock-up) with five degrees of freedom (DOF) for the qualification of control algorithms for the CLIC supporting system active-pre-alignment. Present understanding, lessons learned (“know how”), issues of sensors noise and mechanical components nonlinearities are presented.

WEPPP045

Beam-breakup Analysis for an Annular Cherenkov High Gradient Wakefield Accelerator

wakefield, simulation, vacuum, electron

2822

A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
A. Altmark
LETI, Saint-Petersburg, Russia

Funding: This work is supported by the SBIR Program of the US Department of Energy.
A complete analytical solution for Cherenkov wakefields generated by an azimuthally asymmetric annular beam propagating in a coaxial two-channel dielectric structure is presented. The transformer ratio of the annular beam Cherenkov wakefield accelerator initially proposed by R. Keinigs, M. Jones* is dramatically increased in comparison to a collinear cylindrical wakefield accelerating structure. A particle-Green's function beam dynamics code BBU-3000** to study beam breakup effects has been upgraded to incorporate annular drive beams and coaxial dielectric wakefield accelerating structures*. Beam dynamics simulations of the annular drive beam with asymmetric charge distributions have been carried out to determine the sensitivity of this method to beam imperfections in GHz and THz frequency ranges.
*R. Keinigs, M. Jones, Proc. 7th Int. Conf. High-Power Part. Beams, Beams’88, Karlsruhe, Germany, 864 (1988).
**P. Schoessow et al., AIP Conference Proceedings 1299, 262 (2010).

WEPPP066

Performance Simulations of a Phase Stabilization System Prototype for CTF3

feedback, kicker, simulation, linac

2858

A. Gerbershagen, T. Persson, D. Schulte, P.K. Skowroński
CERN, Geneva, Switzerland
P. Burrows, G.B. Christian
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
A. Gerbershagen, C. Perry
JAI, Oxford, United Kingdom
E. Ikarios
National Technical University of Athens, Athens, Greece

The CLIC drive beam provides RF power for acceleration of the main beam, and hence the drive beam’s longitudinal phase tolerances are very tight. A feedforward chicane consisting of four electromagnetic kickers is proposed as a correction system for the phase errors, which should allow loosening of the tolerances. A prototype of such a chicane system, developed by CERN, INFN and the University of Oxford, is planned to be installed at CFT3 in 2012. The present paper summarizes the parameters of the planned phase correction system and presents simulations, which are used to make predictions of the performance of such a feedforward system at CTF3.

WEPPP068

Latest Performance Results from the FONT5 Intra-train Beam Position and Angle Feedback System at ATF2

feedback, kicker, extraction, linear-collider

2864

D.R. Bett, R. Apsimon, N. Blaskovic Kraljevic, P. Burrows, G.B. Christian, M.R. Davis, A. Gerbershagen, C. Perry
JAI, Oxford, United Kingdom
B. Constance
CERN, Geneva, Switzerland
J. Resta-López
IFIC, Valencia, Spain

A prototype Interaction Point beam-based feedback system for future electron-positron colliders, such as the International Linear Collider, has been designed and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The FONT5 intra-train feedback system aims to stabilize the beam orbit by correcting both the position and angle jitter in the vertical plane on bunch-to-bunch time scales, providing micron-level stability at the entrance to the ATF2 final-focus system. The system comprises three stripline beam position monitors (BPMs) and two stripline kickers, custom low-latency analogue front-end BPM processors, a custom FPGA-based digital processing board with fast ADCs, and custom kicker-drive amplifiers. The latest results from beam tests at ATF2 will be presented, including the system latency and correction performance.

WEPPR004

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

luminosity, resonance, lattice, quadrupole

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.

WEPPR050

Future Colliders Based on a Modulated Proton Bunch Driven Plasma Wakefield Acceleration

electron, plasma, proton, wakefield

3039

G.X. Xia, A. Caldwell
MPI-P, München, Germany
P. Muggli
MPI, Muenchen, Germany

Recent simulation shows that a self-modulated high energy proton bunch can excite large amplitude plasma wakefields and accelerate an external electron bunch to higher energies*. Based on this scheme, future colliders, either an electron-positron linear collider (e⁺e⁻ collider) or an electron-hadron collider (e.g. LHeC) can be conceived. In this paper, we discuss some key design issues for an e⁺e⁻ collider and a high energy LHeC collider, based on the existing infrastructure of the CERN accelerator complex.
* A. Caldwell, K. Lotov, Plasma wakefield acceleration with a modulated proton bunch, arXiv: 1105.1292 (2011).

WEPPR093

Impedance Budget for Crab Cavity in MEIC Electron Ring

impedance, electron, cavity, ion

3153

S. Ahmed, G.A. Krafft, B.C. Yunn
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab has been envisioned as a first stage high energy particle accelerator beyond the 12 GeV upgrade of CEBAF. The estimate of impedance budget is important from the view point of beam stability and matching with other accelerator components driving currents. The detailed study of impedance budget for electron ring has been performed by considering the current design parameters of the e-ring. A comprehensive picture of the calculations involved in this study has been illustrated in the paper.

THYA01

High Field Magnet Developments

dipole, quadrupole, luminosity, alignment

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]

THXB01

Interaction of Muon Beam with Plasma Developed During Ionization Cooling

plasma, wakefield, electron, simulation

3200

S. Ahmed
JLAB, Newport News, Virginia, USA
K.B. Beard, T.J. Roberts
Muons, Inc, Batavia, USA
D.M. Kaplan, L.K. Spentzouris
Illinois Institute of Technology, Chicago, Illinois, USA

Muon collider has been envisioned as a future high energy lepton machine. High luminosity can be obtained by the ionization cooling – best suited for muons due to their short life time. In this cooling process, particles ionize material medium in which they lose momentum, thus the normalized emittance is reduced. The ionized medium is called plasma and the ionization density could increase due to the passage of multiple bunches through the material. This means that the incoming beams interact with plasma together with ionizing the medium used for cooling. It is, therefore, important to investigate the effects of background plasma on the incoming bunches. A comprehensive studies of muon beam propagation through plasma medium using EM particle-in-cell simulations. This computational study involves kinetic model, therefore, provides deep insight of the phenomena, which cannot be obtained by the conventional fluid model. The wakes excited by mu+ and mu- are different due to the beam polarity and depends on their relative densities. Externally applied axial magnetic field suppresses the wakes evolved during the interaction. The details of this study will be discussed in the paper.

Slides THXB01 [4.584 MB]

THYB01

Beam-beam Limit in a Hadron Collider

luminosity, emittance, simulation, resonance

3208

K. Ohmi
KEK, Ibaraki, Japan

Beam-beam limit phenomenon is observed in degradation of luminosity lifetime and/or beam life time in hadron colliders, especially in LHC. We focus the luminosity degradation in this paper. Various effects to degrade the luminosity grow severe in a high beam intensity. Coherent beam-beam instability, incoherent beam-beam emittance growth and those cupeled with lattice errors, external noises, intra-beam scattering. The beam-beam limit in an ideal machine and a machine with above errors is discussed with theory and simulation. Experimental results are reviewed and compare with the theory and simulations.

Slides THYB01 [4.712 MB]

THEPPB012

Pressure Acoustic Waves in Positron Production Targets for Future Lepton Colliders

target, positron, photon, linear-collider

3257

O.S. Adeyemi, V.S. Kovalenko, L.I. Malysheva, G.A. Moortgat-Pick, A. Ushakov
University of Hamburg, Hamburg, Germany
A.F. Hartin
DESY, Hamburg, Germany
F. Staufenbiel
DESY Zeuthen, Zeuthen, Germany

Funding: This work is supported by the German Federal Ministry of Education and Research, Joint Research Project R&D Accelerator "Spin Management", contract number 05H10GUE
Future high energy lepton colliders demand high luminosities to achieve its physics goals. For the electron-positron linear collider, the generation of positrons is a non-trivial problem: the positron production target has to a survive huge amount of energy deposited by the bombardment of intense beams of electrons or photons. This causes a rapid increase of the temperature in the target within a very short time period. The resulting thermal stress induces pressure waves and can substantially shorten the operating life-span of for the target material. In this work, we study linear and effects of induced stress through pressure acoustic waves using a hydrodynamic model. The survivability issue of the target is discussed.

THPPD016

Construction and Measurement of Novel Adjustable Permanent Magnet Quadrupoles for CLIC

quadrupole, permanent-magnet, multipole, 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.

THPPD028

Studies on the LHC Superconducting Circuits and Routine Qualification of Their Functionalities

dipole, cryogenics, hadron, target

3563

M. Pojer, G. D'Angelo, R. Mompo, R. Schmidt, M. Solfaroli Camillocci
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) is systematically undergoing periods of maintenance stop (either 4-5 days stops or longer Christmas breaks), after which some of the superconducting circuits (or the totality of them) have to be re-commissioned to check the correct functionality of all powering and protection systems. Detailed procedures have been developed during the past few years and they have been optimized to increase powering tests efficiency, thus reducing beam downtime. The approach to the routine qualification of the LHC powering systems is described in this paper. During 2011 technical stops, some particular studies on the superconducting circuits were performed, to assess the quality of the superconducting splices of individually powered magnets and to study the quench propagation in the main magnet bus-bars. The methodology of these tests and some results are also presented.

THPPD029

Machine Availability at the Large Hadron Collider

luminosity, cryogenics, controls, hadron

3566

M. Pojer, R. Schmidt, M. Solfaroli Camillocci, S. Wagner
CERN, Geneva, Switzerland

One of the most important parameters for a particle accelerator is its uptime, the period of time when it is functioning and available for use. In its second year of operation, the Large Hadron Collider (LHC) has experienced very high machine availability, which is one of the ingredients of its brilliant performance. Some of the strategies followed to increase MTBF are described in the paper. The approach of periodic maintenance stops, often questioned, is also discussed. Some considerations on the ideal length of a physics fill are also drawn.

THPPD034

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

quadrupole, dipole, 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, quadrupole, 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, quadrupole, 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, quadrupole, 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.

THPPD048

15+ T HTS Solenoid for Muon Accelerator Program

solenoid, laser, power-supply

3617

Y. Shiroyanagi, R.C. Gupta, P.N. Joshi, H.G. Kirk, R.B. Palmer, S.R. Plate, W. Sampson, P. Wanderer
BNL, Upton, Long Island, New York, USA
D.B. Cline
UCLA, Los Angeles, California, USA
J. Kolonko, R.M. Scanlan, R.J. Weggel
Particle Beam Lasers, Inc., Northridge, California, USA

Funding: This work is supported by the U.S.Department of Energy under Contract No. DE-AC02-98CH10886 and SBIR contract DOE Grant Numbers DE-FG02-07ER84855 and DE-FG02- 08ER85037.
This paper will present the construction and test results of a ~10 T insert coil solenoid which is part of a proposed ~35 T solenoid being developed under a series of SBIR contracts involving collaboration between Particle Beam Lasers (PBL) and Brookhaven National Laboratory. The solenoid has an inner diameter of 25 mm, outer diameter of ~95 mm and a length of ~70 mm. It consists of 14 single pancake coils made from 4 mm wide 2G HTS conductor from SuperPower Inc., co-wound with a 4 mm wide, 0.025 mm thick stainless steel tape. These are paired into 7 double pancake coils. Each double pancake coil has been individually tested at 77 K before assembly in a complete solenoid. The solenoid is nearly ready for a high field test at ~4K.

THPPD076

Evaluation of Components for the High Precision Inductive Adder for the CLIC Damping Rings

damping, kicker, emittance, luminosity

3692

J. Holma, M.J. Barnes
CERN, Geneva, Switzerland

The CLIC study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC damping rings will produce, through synchrotron radiation, ultra-low emittance beam with high bunch charge, necessary for the luminosity performance of the collider. To limit the beam emittance blow-up due to oscillations, the pulse generators for the damping ring kickers must provide extremely flat, high-voltage pulses. The specifications for the extraction kickers of the CLIC damping rings are particularly demanding: the flattop of the output pulse must be 160 ns duration, 12.5 kV and 250 A, with a combined ripple and droop of not more than ±0.02 %. An inductive adder allows the use of different modulation techniques and is therefore a very promising approach to meeting the specifications. In addition to semiconductors working in their saturated region, semiconductors working in their linear region are needed for applying analogue modulation techniques. Simulations have been carried out to define component specifications for the inductive adder: this paper reports the results of tests and measurements of various components.

THPPP009

Automated Execution and Tracking of the LHC Commissioning Tests

status, controls, LabView, hadron

3743

K. Fuchsberger, V. Baggiolini, M. Galetzka, R. Gorbonosov, M. Pojer, M. Solfaroli Camillocci, M. Zerlauth
CERN, Geneva, Switzerland

To ensure the correct operation and prevent system failures, which can lead to equipment damage in the worst case, all critical systems in the Large Hadron Collider (LHC), have to be tested thoroughly during dedicated commissioning phases after each intervention. In view of the around 7,000 individual tests to be performed each year after a Christmas stop, a lot of effort was already put into the automation of these tests at the beginning of LHC hardware commissioning in 2005, to assure the dependable execution and analysis of these tests. To further increase the productivity during the commissioning campaigns and to enforce amore consistent workflow, the development of a dedicated testing framework was launched. This new framework is designed to schedule and track the automated tests for all systems of the LHC and will also be extendable, e.g., to beam commissioning tests. This is achieved by re-using different, already existing execution frameworks. In this paper, we outline the motivation for this new framework and the related improvements in the commissioning process. Further, we sketch its design and present first experience from the re-commissioning campaign in early 2012.

THPPP027

The Design of a Large Booster Ring for the Medium Energy Electron-Ion Collider at JLab

booster, ion, dipole, electron

3791

E.W. Nissen, T. Satogata, Y. Zhang
JLAB, Newport News, Virginia, USA

Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In this paper, we present the current design of the large booster ring for the Medium Energy Electron-Ion Collder (MEIC) at JLab. The booster ring takes 3 GeV protons or ions of equivalent energy from a pre-booster ring, and accelerates them to 20 GeV for protons or equivalent energy for light to heavy ions before sending them to the ion collider ring. The present design calls for a figure-8 shape of the ring for superior preservation of ion polarization. The ring is made of warm magnets and shares a tunnel with the two collider rings. Acceleration is achieved by warm RF systems. A linear optics has been designed with the transition energy above the highest beam energy in the ring so crossing of transition energy will be avoided. Preliminary beam dynamics studies including chromaticity compensation, analyses of dynamic aperture, working point and high order effects are also presented in this paper.

THPPP090

Project X Functional Requirements Specification

linac, proton, factory, target

3945

S.D. Holmes, S. Henderson, R.D. Kephart, J.S. Kerby, I. Kourbanis, V.A. Lebedev, C.S. Mishra, S. Nagaitsev, N. Solyak, R.S. Tschirhart
Fermilab, Batavia, USA

Funding: Work supported by the Fermi Research Alliance, under contract to the U.S. Department of Energy.
Project X is a multi-megawatt proton facility being developed to support a world-leading program in Intensity Frontier physics at Fermilab. The facility is designed to support programs in elementary particle and nuclear physics, with possible applications to nuclear energy research. A Functional Requirements Specification has been developed in order to establish performance criteria for the Project X complex in support of these multiple missions, and to assure that the facility is designed with sufficient upgrade capability to provide U.S. leadership for many decades to come. This paper will describe the Functional Requirements for the Project X facility, their recent evolution, and the rationale for these requirements.

FRYCP01

Physics Results at the LHC and Implications for Future HEP Programmes

proton, luminosity, electron, linear-collider

4190

R. Heuer
CERN, Geneva, Switzerland

This presentation should review the accumulated data of the TEVATRON and the first two years of LHC operation, highlighting major results and findings for high energy physics. This talk should highlight the most burning questions in high energy physics that emerged in light of these new results and discuss their implication for the planning and preparation of future accelerator projects.

Slides FRYCP01 [14.536 MB]