WEPC —  Poster Session   (07-Sep-11   16:00—18:00)

Paper	Title	Page
WEPC001	Beam Based Sextupole Alignment Studies for Coupling Control at the ASLS	1995
	R.T. Dowd, Y.E. Tan ASCo, Clayton, Victoria, Australia
	Offsets in sextupole magnets can be a significant source of coupling in a storage ring and hinder efforts to minimize vertical emittance. Beam offsets in the sextupoles at the Australian Synchrotron Light Source were measured using a response matrix analysis in LOCO with differing magnets strengths. These results were used to obtain an estimate of offset in each sextupole as well as estimate quadrupole contributions to coupling.
WEPC002	RF Separator and Septum Layout Concepts for Simultaneous Beams to RIB and FEL Users at ARIEL	1998
	Y.-C. Chao, C. Gong, S.R. Koscielniak TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	A ½ MW capable CW electron linac is being designed and constructed at TRIUMF in support of the existing Rare Isotope Beam program. In the simplest configuration, the beam makes a single pass through three cryomodules to the RIB production targets. However, after the construction of a recirculation path, beam could make a second pass through two cryomodules with the RF phase advance adjusted to give energy recovery. Here it is proposed to time-interleave two bunch trains, and via an RF separator and septum, to direct one single-pass train to RIB production and the second train through the energy recovery ring that contains an IR FEL. It is also the intention, in single user mode, to use the ring as an energy doubler. This paper describes the RF separation scheme and options for the extraction optics that satisfy the requirements of “simultaneous” beams to two users.
WEPC003	Low-Beta Empirical Models used in Online Modeling and High Level Applications	2001
	Y.-C. Chao, G. Goh TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Using empirically models for elements generated by simulations codes such as Astra in low-beta beamline to provide efficient and more accurate models for machine diagnostic and tuning is discussed. Experience of such application in the framework of XAL may also be presented.
WEPC004	Comparison of the Action and Phase Analysis on LHC Orbits with Other Techniques	2004
	J.F. Cardona UNAL, Bogota D.C, Colombia R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands
	Funding: DIB-Universidad Nacional de Colombia Recently acquired turn-by-turn data of the LHC is analyzed using the action and phase jump technique. The results of this analysis show a visible variation of the action and phase plots at the interaction regions from which optic error estimations can be done. In this paper error estimations will be presented and comparisons with other existing techniques in the LHC, such as the recently implemented Segment-by-segment technique, will be discussed.
WEPC005	Concept for Controlled Transverse Emittance Transfer within a Linac Ion Beam	2007
	L. Groening GSI, Darmstadt, Germany
	Generally the two transverse emittances of a linac beam are quite similar in size (round beam). However, injection into subsequent rings often imposes stronger limits for the upper allowed value to one of these emittances. Provision of flat linac beams (different transverse emittances) thus can considerable increase the injection efficiency into rings. Round-to-flat transformation has been already demonstrated for electron beams. It was also proposed for angular momentum dominated beams from Electron-Cyclotron-Resonance sources. We introduce a concept to extend the transformation to ion beams that underwent charge state stripping without requiring their extraction from an ECR source. The concept is of special interest for beams from low-charge-state / high-particle-current sources. It can be also applied to stripping of H− to proton beams.
WEPC006	Upgrade Plans on the Superconducting Electron Accelerator S-DALINAC	2010
	M. Kleinmann, R. Eichhorn, F. Hug, N. Pietralla TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by DFG through SFB 634 The S-DALINAC is a superconducting recirculating electron accelerator with maximum design energy of 130 MeV operating in cw at 3 GHz. Even so the gradients of the superconducting cavities are well above design, their design quality factor of 3*109 have not been reached so far, leading to higher heat transfer into the liquid helium than expected. Due to the limited cooling power of the cryo-plant being 120 W, the final energy achievable in cw operation is around 85 MeV, currently. In order to provide a cw beam with the designed final energy in the future, the installation of an additional recirculation path is projected. We will report on the beam-line and the magnet design for the new recirculation path. In addition, we will present the layout of two proposed scraper-systems which will be used to remove the halo of the electron beam allowing high precision coincidence experiments with very low background for nuclear physics in the future.
WEPC007	Large Energy Acceptance Dogleg for the European XFEL Injector	2013
	N. Golubeva, V. Balandin, W. Decking DESY, Hamburg, Germany
	The option to install two injectors is foreseen at the European XFEL Facility. The injectors will be located on top of each other in the same building, both with the offset of 2.75 m with respect to the main linac axis. The translation system (dogleg) from the injector axis to the main linac axis has to fulfill very tight requirements of the chromatic properties, because the energy chirp required for the downstream bunch length compression in magnetic chicanes will be created upstream in the injector linac. In this paper we present such an large energy acceptance dogleg and discuss the optical symmetries which form the basis of its design.
WEPC008	Optics for the Beam Switchyard at the European XFEL	2016
	N. Golubeva, V. Balandin, W. Decking DESY, Hamburg, Germany
	The European XFEL is planed as a multi-user facility with the possibility to distribute electron bunches of one beam pulse to different beamlines. The initial stage foresees two electron beamlines each serving its own set of undulators. The later addition of a third beamline is also considered in the design of the distribution system. In addition, the integration of the transport line to the beam abortion dump allows a flexible selection of the bunch repetition pattern for each beamline. The beam extraction, both in undulator beamlines and in the beamline to the dump, will be realized with fast kickers and a Lambertson septum. In this paper we describe the magnet lattice of the deflection arcs with simultaneous horizontal and vertical dispersions and the beam optics of the beam switchyard.
WEPC009	Design of an Antiproton Injection and Matching Beam Line for the AD Recycler Ring	2019
	O. Karamyshev, G.A. Karamysheva MPI-K, Heidelberg, Germany O. Karamyshev, A.I. Papash JINR, Dubna, Moscow Region, Russia M.R.F. Siggel-King, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG.328. A small antiproton recycler ring (AD-Rec) for use in the MUSASHI beamline at the CERN AD has been designed by the QUASAR Group for operation at energies between 3 and 30 keV. A highly efficient beam line for capturing the beam after extraction from the trap, transporting and injecting it into the AD Rec is very important to minimize losses and full the ring up to its space charge limit. In this contribution, the beam optical and mechanical design of the injector is presented.
WEPC010	Investigations into Efficient Extraction and Acceleration of Beams from Ion Traps	2022
	O. Karamyshev, G.A. Karamysheva MPI-K, Heidelberg, Germany O. Karamyshev, A.I. Papash JINR, Dubna, Moscow Region, Russia M.R.F. Siggel-King, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG.328 A number of exotic ion species, such as for example radioactive isotopes or antiprotons, are highly desirable at very low energies of some tens of keV for fundamental studies. In order to obtain cooled beams with low emittance and low momentum spread, these particles are often first captured in an ion trap, cooled and then extracted and accelerated before being used in experiments. The extraction mechanism and subsequent beam handling impacts critically on the final beam quality. In this contribnution, an optimized scheme for efficient beam extraction and acceleration from ion traps is presented. Field maps from different existing ion trap setups, such as for example the Musashi trap at CERN, are used as a basis for simulation studies into the beam dynamics. Input and final beam emittances are analyzed as a function of the extraction and acceleration field geometries and the performance of different possible scenarios is directly compared.
WEPC011	Ion Optical Design of the Low Energy Ion Beam Facility at IUAC	2025
	A. Mandal, D. Kanjilal, S. Kumar, G. Rodrigues IUAC, New Delhi, India
	A Low Energy Ion Beam Facility (LEIBF) using fully permanent magnet ECR ion source (Nanogan) has been installed at Inter University Accelerator Centre (IUAC), New Delhi for fundamental research on Atomic and Molecular Physics, and Material Science. The accelerator consists of an ECR ion source, 400 kV accelerating column and an analyzing-cum switching magnet with three beam ports at 75, 90 and 105 degrees. The complete ion optics from ECR ion source to the target has been simulated using TRANSPORT* and GICOSY** ion optics codes. The ions from the ECR source are typically extracted at 15 kV which are further accelerated by 400 kV accelerating column. The analyzing cum switching magnet has been designed to analyze different beams and to switch in a particular beam line. It is a H shaped dipole magnet having pole gap of 65 mm, maximum magnetic field of 1.5 T and radius of 529 mm for 90 degree bend. The entrance and exit edge angles for three beam lines have been optimized to obtain double focus in all beam lines. The beam is further transported to target locations using electrostatic quadrupole triplet. The details of ion optics will be presented in the paper. * K.L. Brown, D.C. Carey, Ch. Iselin and F. Rothacker: Transport, See yellow reports CERN 73-16 (1973) & CERN 80-04 (1980). ** H.Weick, GICOSY homepage, http://www-linux.gsi.de/~weick/gicosy/.
WEPC012	Steering-corrected 88 MHz QWRs for SARAF Phase II	2028
	J. Rodnizki, J. Ashkenazy, D. Berkovits, Z. Horvitz Soreq NRC, Yavne, Israel A. Kolomiets, B. Mustapha, P.N. Ostroumov ANL, Argonne, USA
	Funding: This work is partially supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. SARAF phase II linac is designed for 5 mA 40 MeV proton and deuteron beams. One option is to base the design on Quarter Wave Resonators (QWR). It is suggested to compensate the QWR non-symmetric magnetic field component by introducing a drift tube face tilt angle*. Here we explore the applicability of this steering correction scheme to the acceleration of a CW high current low β light ion beam in an end-to-end 88 MHz QWR lattice. This can serve as a case study for multi-megawatt machines that are currently being designed by ANL. An analytical approximation is used to evaluate the on-axis beam steering behavior. Two 88 MHz QWR cavities, β=0.08 and 0.15, were designed, field and beam dynamics were simulated and optimized. Using the tube face tilt angle concept the beam steering along a QWR can be reduced to the order of 0.1 mrad. Beam dynamics lattice examination including error analysis demonstrated an efficient high performance 40 MeV linac based on 3 superconducting modules with 19 QWRs (Ep < 35 MV/m and Bp < 70 mT). The fields obtained at recent ANL tests for a 73 MHz QWR (70 MV/m and 105 mT) imply that Ep is not a real limiting factor. * P.N. Ostroumov and K. W. Shepard, PRST-AB 4, 110101 (2001).
WEPC013	Tests for Low Vertical Emittance at Diamond using LET Algorithm	2031
	S.M. Liuzzo, M.E. Biagini, P. Raimondi INFN/LNF, Frascati (Roma), Italy R. Bartolini JAI, Oxford, United Kingdom
	We present measurements recently performed at the Diamond Light Source, aimed at the achievement of low vertical emittance using the Low Emittance Tuning (LET) algorithm developed for a SuperB factory project presently in progress. The tests have been focused on the comparison between this method and the LOCO algorithm currently used at Diamond. Beam position monitor tilts estimate and multiple coupling response matrices have been introduced in the algorithm in order to optimize the procedure. After few iterations using vertical correctors and skew quadrupoles, very low vertical dispersion and emittance coupling, comparable to those obtained by LOCO, have been measured.
WEPC014	Beam Dynamics Simulations of the PIAVE-ALPI Linac	2034
	M. Comunian, E. Fagotti, F. Grespan, A. Palmieri, A. Pisent, C. Roncolato INFN/LNL, Legnaro (PD), Italy
	At the Legnaro National Laboratories it is operating a SuperConducting linac for nuclear studies. The ALPI linac is injected either by a XTU tandem, up to 14 MV, or by the s-c PIAVE injector, made with 2 SC-RFQ. The main part of the linac (at the present 64 cavities for a total voltage up to 48 MV) is build up in two branches connected by an achromatic and isochronous U-bend. The PIAVE-ALPI complex is able to accelerate beams up to A/q = 7. The layout of the linac ALPI is, from the point of beam dynamics, quite complex due the presence of RFQs, cavities, dipoles, magnets, etc. These elements behaviors are entirely not linear, so a small change on the settings can induce a big change in the Linac beam dynamics. An automatic tuning procedure and a full field maps description are mandatory to handle a so high number of active components. The program used at this scope is TraceWin that is able to do an envelope simulation and a full multiparticles simulation.
WEPC015	Tuning Methods for HIMAC Multiple-energy Operation	2037
	K. Katagiri, T. Furukawa, Y. Iwata, K. Noda, S. Sato, T. Shirai NIRS, Chiba-shi, Japan K. Mizushima Chiba University, Graduate School of Science and Technology, Chiba, Japan E. Takeshita Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan
	Beam stability of multiple-energy operation at HIMAC synchrotron was improved for the fast raster-scanning irradiation. In order to improve the transverse stability, the working point of the betatron tune was investigated during one operation cycle. The signals were collected from the beam position monitor using a fast data-acquisition unit. The temporal evolution of the horizontal and vertical betatron tune was evaluated by using the short time Fourier transform. Analyzed results showed that variation of the betatron tune in the acceleration interval passed through the 3rd-order coupling resonance line, and it caused undesirable emittance growth. In order to keep the working point within the desirable operating region, the current pattern of the power supplies for the quadrupole magnets was corrected by using the variation of the betatron tune. The experimental results showed that the working point could be successfully stabilized, and the undesirable beam losses could be reduced during the acceleration interval.
WEPC016	Amplitude Dependent Orbit Shift and its Effect on Beam Injection	2040
	Y. Shoji LASTI, Hyogo, Japan T. Nakamura, J. Schimizu, M. Takao JASRI/SPring-8, Hyogo-ken, Japan
	The betatron oscillation amplitude dependent orbit shift was measured at the electron storage ring, NewSUBARU. The result roughly agreed with the theoretical calculation. The effect of this shift on the beam injection is discussed using parameters of NewSUBARU and SPring-8. Generally there exists a better side for the injection, the inner side or the outer side of the ring, which depends on the sign of the orbit shift at the injection septum. In case of the NewSUBARU, the beam is injected from the outer side and the shift is positive. The effective thickness of the septum is reduced by the large oscillation amplitude of the injected beam. On the other hand at SPring-8, the beam is injected from the inner side of the ring while the orbit shift is negative. This means that the two rings are using better side for the injection.
WEPC017	Vertical Beam Size Correction at the SSRF Storage Ring	2043
	M.Z. Zhang, J. Hou, B.C. Jiang, H.H. Li, S.Q. Tian SINAP, Shanghai, People's Republic of China
	Vertical beam size is an important parameter for 3rd generation light source. Correcting the vertical beam size is a realistic way to increase brightness or beam lifetime without any additional equipments in a machine under operation. The main sources of vertical beam size are betatron coupling and vertical dispersion. At the SSRF storage ring, LOCO is used for vertical dispersion and coupling measurements and corrections. The betatron coupling and vertical dispersion is corrected by skew quadrupoles that calculated by LOCO. Vertical beam size can be changed from 10s um to several um for different purposes. Touschek lifetime is also measured to testify the vertical beam size. Simulations show that if smaller vertical beam size is required, more skew quadrupoles are needed.
WEPC018	Self-focusing Effects in Compact C-band Standing-wave Accelerating Structure for X-ray Imaging Applications	2046
	H.R. Yang, M.-H. Cho, S.H. Kim, W. Namkung, S.J. Park POSTECH, Pohang, Kyungbuk, Republic of Korea J.-S. Oh NFRI, Daejon, Republic of Korea
	In electron RF linacs for industrial X-ray imaging applications, compact structures are preferred for mobility. The electron beam spot size of 1 – 2 mm is required for the spatial resolution of images at the X-ray conversion target. Applying self-focusing effects to the accelerating structure, external magnets can be removed and then the accelerator system becomes more compact. We design a C-band electron linac, which is capable of producing 6-MeV, 80-mA pulsed electron beams with an RF power of 1.5 MW. It uses a bi-periodic and on-axis-coupled accelerating structure with a built-in bunching section. It uses the π/2-mode standing-waves. The first bunching cell has an asymmetric geometry which maximizes the RF phase focusing. On the other hand, the normal cells are designed for the electrostatic focusing to be maximized. In this paper, we present design details of the accelerating cells and the beam dynamics simulation by the PARMELA code.
WEPC021	Optical Design of the Proton Beam Lines for the Neutron Research Complex INR RAS and Medical Application	2049
	M.I. Grachev, E.V. Ponomareva RAS/INR, Moscow, Russia
	The optical design for the layout of the beam lines for the neutron research complex INR RAS and medical application on the basis of the Linear accelerator are presented here. The proposed schemes have been realized at the INR RAS. The necessary size and shape of the proton beam at the location of the neutron target are obtained. Methods and results for the tuning of the high current beams are presented in this paper.
WEPC023	Beam Dynamics Simulations for the ESS-Bilbao H− Ion Source	2052
	I. Bustinduy, F.J. Bermejo, D. Fernandez-Cañoto, J.L. Munoz, I. Rodríguez ESS Bilbao, Bilbao, Spain M. Eguiraun, J. Feuchtwanger, Z. Izaola ESS-Bilbao, Zamudio, Spain
	Simulations are performed for the Ion Source Test Stand (ITUR) of the ESS-Bilbao research accelerator facility. The beam dynamics is investigated as a function of the extraction voltages, the ion current, and the inclination angle of the ion source. The ITUR Penning H− ion source has the plasma aperture plate and extraction electrode inclined a certain angle with respect to the vertical axis to compensate for the Penning magnets field. The negative charged particles are extracted through a rectangular slit of 10×6 mm2. The extraction system is mainly composed of two devices, a rectangular extraction electrode and a refrigerated trumpet shaped device acting as an Einzel lens to focus the beam, and also, as a trap for neutral cesium atoms exiting from the source. Results are calculated and analyzed at the DC Current Transformer and pepperpot positions located at 245 mm and 882 mm from the ion source.
WEPC024	LOCO in the ALBA Storage Ring	2055
	G. Benedetti, D. Einfeld, Z. Martí, M. Muñoz CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	ALBA is a 3 GeV 3rd generation light source which achieved first stored beam in February 2011, and will be commissioned during 2011. The ring comprises of 112 independent quadrupoles grouped in 14 families and 32 combined gradient dipoles powered in series. This paper reviews the process of recovering the design lattice and the symmetry of the machine, and the effects on orbit and lifetime. The main tool employ for this has been the LOCO implementation provided in the Matlab MiddleLayer. First results shows that the main effect on the symmetry is the difference between bending magnets. As this effect can not be compensated locally at present at the bendings, a global optics correction using all the quadrupoles is used.
WEPC025	Modeling Results of the ALBA Booster	2058
	G. Benedetti, D. Einfeld, U. Iriso, J. Marcos, Z. Martí, M. Muñoz, M. Pont CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	The 3rd generation light source ALBA is in the process of being commissioned. The full energy 3 GeV booster synchrotron was commissioned in the during 2010, ramping the beam from extracted from the LINAC from an energy of 110 MeV to the 3 GeV required for injection in the storage ring. The lattice is based in combined function bending magnets, providing a small emittance beam (< 12 nmrad) at extraction. This paper reviews the agreement between the optics modeling and the measures performed during the commissioning, with special regard to the optics measurement during the ramping process. The results from the magnetic measurement for the combined magnets while ramping are included in the model to explain the movement of the tunes during the ramp.
WEPC028	Record Low Beta-beat of 10% in the LHC	2061
	G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands M. Aiba PSI, Villigen, Switzerland R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland
	During the 2011 LHC run several measurements and correction campaigns were conducted. As a result a peak beta-beat of 10% level was achieved. This level, well below the specified tolerances of the LHC, improves the aperture margins and helps minimize the luminosity imbalance between the different experiments. A combination of local corrections at the insertion regions and an overall global correction were used to achieve this record low beta-beat. The sequence of the optics corrections and stability along the 2011 run are reported.
WEPC029	Accuracy of the LHC Optics Measurement based on AC Dipoles	2064
	R. Miyamoto, R. Calaga BNL, Upton, Long Island, New York, USA R. Tomás, G. Vanbavinckhove CERN, Geneva, Switzerland
	Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP). The tight tolerances in the LHC requires optics measurement with very good accuracy. Therefore, AC dipoles are employed as the primary devices to measure the LHC optics. The accuracy of the measurement is mainly determined by the length of the coherent signal, signal-to-noise ratio of the measurement, and the data processing to effectively suppress the noise. This paper presents numerical and experimental studies of how these factors affect the accuracy of the LHC optics measurement using the AC dipoles.
WEPC030	Measurement of Coupling Resonance Driving Terms in the LHC with AC Dipoles	2067
	R. Miyamoto, R. Calaga BNL, Upton, Long Island, New York, USA M. Aiba PSI, Villigen, Switzerland R. Tomás, G. Vanbavinckhove CERN, Geneva, Switzerland
	Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP). Transverse betatron coupling in the LHC is measured from Fourier analysis of turn-by-turn beam oscillations excited by AC dipoles. The use of the AC dipole for optics measurements induces a small systematic error which can be corrected with an appropriate data interpretation. An algorithm to apply this correction to the measurement of the coupling resonance driving terms is developed for the first time. This paper will review this new algorithm and present results of its application to the LHC.
WEPC031	Optics Corrections at RHIC	2070
	G. Vanbavinckhove CERN, Geneva, Switzerland M. Bai, G. Robert-Demolaize BNL, Upton, Long Island, New York, USA
	Excessive beta-beat, deviation of measured beta function from the calculated beta functions based on an model, in high energy colliders can lead to large deviation of beta function at collision point as well as other adverse effects. The segment-by-segment technique was successfully demonstrated in the LHC operation for reducing the beta-beat. It was then applied to RHIC polarized proton operation in 2011. This paper reports the experimental results of optics correction at RHIC. Future plan is also presented.
WEPC032	First Measurements of Higher Order Optics Parameters in the LHC	2073
	G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands M. Aiba PSI, Villigen, Switzerland R. Bartolini Diamond, Oxfordshire, United Kingdom R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA M. Giovannozzi, F. Schmidt, R. Tomás CERN, Geneva, Switzerland E.H. Maclean JAI, Oxford, United Kingdom
	Higher order effects can play an important role in the performance of the LHC. Lack of knowledge of these parameters can increase the tune footprint and compromise the beam lifetime. First measurements of these parameters at injection and flattop have been conducted. Detailed simulations are compared to the measurements together with discussions on the measurement limitations.
WEPC033	Decoupling Problem of Weakly Linear Coupled Double Mini-beta-y Lattice of TPS Storage Ring	2076
	H.-P. Chang, C.C. Chiang, M.-S. Chiu NSRRC, Hsinchu, Taiwan
	Three double mini-beta-y (DMBy) lattice design of the TPS storage ring is in progress to enhance the photon sources at three of the six long straight sections. For the estimation of Touschek beam lifetime, the TRACY code is used to calculate the momentum acceptance of the linear coupled TPS 3-DMBy lattice. The weak linear coupling was generated by adding some random skew quadrupoles at all quadrupole locations in order to create 1% coupling. Using the Teng’s symplectic rotation form in program may cause trouble in decoupling the one-turn coupled matrix. This report describes how we solve this decoupling problem and some useful references and comments are also presented.
WEPC034	High-level Application Programs for the TPS Commissioning and Operation at NSRRC	2079
	F.H. Tseng, H.-P. Chang, C.C. Chiang NSRRC, Hsinchu, Taiwan
	For the Taiwan Photon Source (TPS) commissioning and operation we have developed more MATLAB-based application programs and tested them on the Taiwan Light Source (TLS). These additional applications built with the MATLAB Middle Layer (MML) include beta function measurement, dispersion function measurement, chromaticity measurement, chromaticity correction, and tune control. In this paper, we will illustrate what algorithms we use in these applications and show the test results. Especially, in order to get the first beam in the TPS commissioning, we adopt the RESOLVE algorithm for the beam steering and it has been built successfully in UNIX-like systems such as Mac OSX and different Linux versions. It can provide us some exercises of error finding and correction before the TPS commissioning in 2013.
WEPC035	Double Mini-Betay Lattice for TPS Storage Ring	2082
	M.-S. Chiu, H.-P. Chang, C.-T. Chen, C.C. Chiang, C.-C. Kuo, Y.C. Lee, H.-J. Tsai, C.H. Yang NSRRC, Hsinchu, Taiwan
	Based on our previous design of double mini-betay optics in one 12-m straight section, NSRRC plan to implement the double mini-betay lattice in three 12-m straight sections in TPS storage ring. Those three locations chosen for double mini-betay lattice still retain the symmetry of accelerator lattice. The two symmetric minima of the vertical beta function will be created in the center of three 12-m straight sections, respectively. We strived to obtain a linear lattice such that there is no significant increase in the natural emittance. Efforts were devoted to optimize the nonlinear beam dynamics with various simulation tools. Preliminary results will be reported.
WEPC036	Coherent Synchrotron Radiation Source Based on an Isochronous Accumulator Ring with Femtosecond Electron Bunches	2085
	N.Y. Huang NTHU, Hsinchu, Taiwan H. Hama, F. Hinode, S. Kashiwagi, M. Kawai, X. Li, F. Miyahara, T. Muto, K. Nanbu, Y. Tanaka Tohoku University, Research Center for Electron Photon Science, Sendai, Japan W.K. Lau NSRRC, Hsinchu, Taiwan
	A compact isochronous accumulator ring has been studied as a source of coherent synchrotron radiation (CSR) at a wavelength region from THz to GHz. Since the thermionic rf gun is substantially stable in general, we anticipate a bunch train of very short electron pulses can be provided satisfactorily by means of velocity bunching. Careful numerical simulations show possibility of the bunch length of much less than 100 fs with a bunch charge of 20 pC, which will contain sufficiently large form factor for production of CSR at the wavelengths longer than ~ 0.1 mm. The coherent THz radiation of high average power will be achieved if the short bunches can be circulated in the accumulator ring without bunch lengthening. This paper will describe the optimization of thermionic injector to produce femtosecond bunches in addition to study of the lattice designing of complete isochronous optics for the accumulator ring.
WEPC037	An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade	2088
	S.D. Fartoukh CERN, Geneva, Switzerland
	A novel optics concept has been invented and developed in the context of the LHC Upgrade studies. It offers an incredibly powerful and flexible machinery in order to squeeze beta* in a symmetric or asymmetric way (so-called “round” or “flat” optics, respectively), while perfectly controlling the chromatic aberrations induced (off-momentum beta-beating, non-linear chromaticity, spurious dispersion due to the crossing angles). The basic principles of the scheme are described and a specific path for the LHC upgrade is built accordingly, only relying on the existing and well-characterized LHC-like technology, and based on the production of flat collision optics with very small beta* (7.5 cm) in the plane perpendicular to the crossing plane.
WEPC038	Beam Line Design and Beam Measurement for TPS Linac	2091
	K.L. Tsai, H.-P. Chang, C.-T. Chen, C.-S. Fann, K.T. Hsu, S.Y. Hsu, C.-Y. Liao, K.-K. Lin, H.M. Shih NSRRC, Hsinchu, Taiwan K. Dunkel, C. Piel RI Research Instruments GmbH, Bergisch Gladbach, Germany
	A beam line for examining the beam quality of TPS (Taiwan Photon Source) linac was designed and constructed in NSRRC. Beam parameters, such as energy, emittance and charge etc., are verified by using the equipments setup in the beam line for this purpose. The lattice design and its manipulation for the parameter measurements are presented in this report. Preliminary results and the tools associating with the measurement are briefly described.
WEPC039	Modelling of the FETS MEBT Line using GPT	2094
	D.C. Plostinar STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom R. Enparantza, M. Larrañaga Fundación TEKNIKER, Eibar (Gipuzkoa), Spain
	The Front End Test Stand project (FETS) currently under construction at Rutherford Appleton Laboratory (RAL) will accelerate a 60 mA, 2 ms, 50 pps H− beam up to 3 MeV. It consists of an H− ion source, a three-solenoid low energy beam transport line (LEBT), an RFQ and a medium energy beam transport line (MEBT) with a fast-slow beam chopping system. As part of the MEBT development, a GPT simulation model has been prepared. The aim is to analyse and understand the transport of intense beams and the beam behaviour in the space-charge dominated regime. The beam quality is then evaluated in terms of RMS emittance growth, beam loss, chopping efficiency and halo development. Results previously obtained with different simulation codes are discussed throughout the paper.
WEPC040	Initial 2D Investigations into the Design and Parameters of an EM Quadrupole for FETS	2097
	M. Larrañaga, R. Enparantza Fundación TEKNIKER, Eibar (Gipuzkoa), Spain D.C. Plostinar STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	The Medium Energy Beam Transport (MEBT) line for the Front End Test Stand (FETS) at Rutherford Appleton Laboratory (RAL) consists of a number of quadrupoles, re-bunching cavities and a fast-slow chopping system with dedicated beam dumps, as well as diagnostics. The type and design of the quadrupoles to be used merits special attention. Due to space restrictions, a hybrid quadrupole solution has been proposed in the past. However, because of the limited range of field adjustability achievable, this approach is not ideal. In this paper, a very preliminary investigation of an electromagnetic quadrupole (EMQ) design is presented. Magnetic simulations results performed with a 2D simulation code will be discussed including magnet optimisation details.
WEPC041	Conceptual Design of a New 800 MeV H− Linac for ISIS Megawatt Developments	2100
	D.C. Plostinar, C.R. Prior, G.H. Rees STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Several schemes have been proposed to upgrade the ISIS Spallation Neutron Source at Rutherford Appleton Laboratory (RAL). One scenario is to develop a new 800 MeV, H− linac and a ~3 GeV synchrotron, opening the possibility of achieving several MW of beam power. In this paper the design of the 800 MeV linac is outlined. It consists of a 3 MeV Front End similar to the one now under construction at RAL (the Front End Test Stand -FETS). Above 3 MeV, a 324 MHz DTL will be used to accelerate the beam up to ~75 MeV. At this stage a novel collimation system will be added to remove the halo and the far off-momentum particles. To achieve the final energy, a 648 MHz superconducting linac will be employed using three families of elliptical cavities with transition energies at ~196 MeV and ~412 MeV. Alternative designs are also being investigated.
WEPC042	Implementation of Double Mini-beta Optics at the Diamond Light Source	2103
	B. Singh, R.T. Fielder, I.P.S. Martin, G. Rehm Diamond, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	Funding: Diamond Light Source Ltd. We report the results of the implementation of two vertical mini-beta and horizontally focusing optics at the Diamond light source, the first in August 2010 and the second in March 2011. Commissioning results of the two optics changes and experimental characterization of the optics are compared with the expected performance and theoretical modeling. The implications of a possible third customized optics are also investigated.
WEPC043	Beam Transport in a Dielectric Wall Accelerator for Intensity Modulated Proton Therapy	2106
	Y.-J. Chen, D.T. Blackfield, S.D. Nelson, B. R. Poole LLNL, Livermore, California, USA
	Funding: This work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA2A27344. We are developing a compact dielectric wall accelerator (DWA) for intensity modulated proton therapy (IMPT) with a goal of fitting the compact proton DWA in a single room*. To make the accelerator compact, the DWA needs to have a very high accelerating gradient. Also, beam transport in the DWA should be done with as few external lenses as possible. We have developed a transport scheme to transport the proton bunch in the DWA and to focus the charge bunch on the patient without using any external focusing lenses. The transport scheme would allow us change the proton beam spot size on the patient easily and rapidly. Results of simulations using 3-D, EM PIC code, LSP** will be presented. * G. J. Caporaso, Y-J Chen and S. E. Sampayan, Rev. of Accelerator Science and Technology, vol. 2, p. 253 (2009). ** Alliant Techsystems Inc., http://www.lspsuite.com/.
WEPC044	Minimizing Beam Motion in a Long-pulse Linear Induction Accelerator	2109
	C. Ekdahl, E.O. Abeyta, J.B. Johnson, K. Nielsen, M.E. Schulze LANL, Los Alamos, New Mexico, USA T.P. Hughes, C.H. Thoma Voss Scientific, Albuquerque, New Mexico, USA C.-Y. Tom NSTec, Los Alamos, New Mexico, USA
	Funding: This work was supported by the US National Nuclear Security Agency and the US Department of Energy under contract DE-AC52-06NA25396. The Dual Axis Radiography for Hydrodynamic Testing (DARHT) Facility at Los Alamos uses two linear induction accelerators (LIAs) for flash radiography of explosively driven experiments from orthogonal viewpoints. The DARHT Axis-II long-pulse 1.8-kA, 16.5-MeV LIA is unique. It has a beam pulse with a 1600-ns flattop during which the kinetic energy varies < 2%. During this flattop, a kicker cleaves out four short micro-pulses, which are focused onto a high-Z target and converted to bremsstrahlung for multi-pulse flash radiography of the experiments. Asymmetric injection of the beam into the solenoidal focusing field, small temporal variations in accelerating potentials, and slight cell misalignments cause the beam position to wander during the flattop. This is undesirable for radiography, because it causes a displacement of the four radiographic source spots. Since the specific energy deposition from each micro-pulse can vaporize target material, succeeding pulses impact an asymmetric object causing a distortion of the source spot. This presentation will review the physics of the beam motion and the tuning procedures we have optimized to minimize the number of shots required.
WEPC045	Transverse Emittance Reduction with Tapered Foil	2112
	Y. Jiao, Y. Cai, A. Chao SLAC, Menlo Park, California, USA
	Funding: The work is supported by the U.S. Department of Energy under contract No. DE-AC02-76SF00515. The idea of reducing transverse emittance with tapered energy-loss foil is proposed by J.M. Peterson in 1980s and recently by B. Carlsten. In present paper, we present the physical model of tapered energy-loss foil and analyze the emittance reduction using the concept of eigen emittance. The study shows that, to reduce transverse emittance, one should collimate at least 4% of particles which has either much low energy or large transverse divergence. The multiple coulomb scattering is not trivial, leading to a limited emittance reduction ratio.
WEPC047	Crab Crossing Schemes and Studies for Electron Ion Collider	2115
	S. Ahmed, S.U. De Silva, Y.S. Derbenev, G.A. Krafft, V.S. Morozov, B.C. Yunn, Y. Zhang JLAB, Newport News, Virginia, USA A. Castilla, J.R. Delayen ODU, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Medium Energy Electron Ion Collider (MEIC) at JLab has been envisioned as future high energy particle accelerator beyond 12 GeV upgrade of CEBAF. Crab crossing of colliding electron and ion beams is essential for accommodating high bunch repetition frequency in the conceptual design of MEIC. The scheme eliminates parasitic beam-beam interactions and avoids luminosity reduction by restoring head-on collisions at interaction points. This requires the separation of two beams quickly to avoid parasitic collisions and the minimization of synchrotron-betatron resonance near IP which can be fulfilled by employing the crab crossing concept first proposed by R. Palmer. Let us call this original scheme as transverse crabbing for the sake of comparison with dispersive crabbing which employs the existing accelerating/bunching RF cavities and dispersion function in the section where the cavity is installed as originally proposed by G. Jackson. In this paper, we report the beam transport and optics for both transverse and dispersive crabbing schemes followed by basic beam dynamics. Moreover, alignment and stability calculations together with synchro-betatron beam dynamics will be discussed.
WEPC048	Calibrating Transport Lines using LOCO Techniques	2118
	Y. Roblin JLAB, Newport News, Virginia, USA
	Funding: Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 With the 12GeV upgrade underway at CEBAF, there is a need to recharacterize the beamlines after the modifications made to it to accommodate running at higher energies. We present a linear perturbation approach to calibrating the optics model of transport lines. This method is adapted from the LOCO method in use for storage rings. We consider the effect of quadrupole errors, dipole construction errors as well as beam position monitors and correctors calibrations. The ideal model is expanded to first order in Taylor series of the quadrupole errors. A set of difference orbits obtained by exciting the correctors along the beamline is taken, yielding the measured response matrix. An iterative procedure is invoked and the quadrupole errors as well as beam position monitors and corrector calibration factors are obtained. Here we present details of the method and results of first measurements at CEBAF in early 2011 Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes
WEPC049	Operation and Storage Ring Calibration with the Transverse Bunch-by-Bunch Feedback System at the Australian Synchrotron	2121
	M.J. Boland, Y.E. Tan ASCo, Clayton, Victoria, Australia D.J. Peake, R.P. Rassool, K.P. Wootton The University of Melbourne, Melbourne, Australia
	The first operational experience with the transverse bunch-by-bunch feedback system for the storage ring shows a doubling of the lifetime and the ability to damp instabilities caused by IVU gap changes. The system was also used to calibrate the ring by doing simultaneous measurements on several single bunches with different bunch currents. Using the bunch-by-bunch system's capability to excite the beam to large amplitudes, the non-linear beam dynamics were also measured and compared with the model.
WEPC050	New Optics for the SOLEIL Storage Ring	2124
	P. Brunelle, F. Briquez, A. Loulergue, O. Marcouillé, A. Nadji, L.S. Nadolski, M.-A. Tordeux, J.F. Zhang SOLEIL, Gif-sur-Yvette, France
	SOLEIL, the French 2.75GeV synchrotron light source is delivering photons to 24 beam lines and is presently equipped with 22 insertion devices (ID) including a high field and small gap in-vacuum wiggler*. This paper presents the continuous work performed to reduce the strong non linear effects of several IDs. On one side, the ID defaults have been precisely identified using on-beam measurements, and magnetic correction developments are going on, especially for the in-vacuum wiggler and for the 10m long HU640 undulator. On the other side, a new optics has been optimised in terms of beta-functions (at the ID location) and non linear dynamics in order to improve the injection efficiency and the beam lifetime in the presence of IDs. The modified optics has been used daily in operation since November 2010 and ensures a beam lifetime greater than 10h for a 400mA stored beam with the users ID configuration. In parallel, an extensive experimental optimization has been performed to prepare the operation with an additional quadrupole triplet that provides double low vertical beta functions in one long straight section that will accommodate two canted in-vacuum insertion devices**. * O. Marcouillé et al., IPAC10, p. 3102 (2010). ** A. Loulergue et al., IPAC10, p. 2496 (2010).
WEPC051	Effect of Compton Scattering on the Electron Beam Dynamics at the ATF Damping Ring	2127
	I. Chaikovska, C. Bruni, N. Delerue, A. Variola, Z.F. Zomer LAL, Orsay, France K. Kubo, T. Naito, T. Omori, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	Compton scattering provides one of the most promising scheme to obtain polarized positrons for the next generation of e+e− colliders. Moreover it is an attractive method to produce monochromatic high energy polarized gammas for nuclear applications and X-rays for compact light sources. In this framework a four-mirror Fabry-Perot cavity has been installed at the Accelerator Test Facility (ATF - KEK, Tsukuba, Japan) and will be used to produce an intense flux of polarized gamma rays by Compton scattering. For electrons at the energy of the ATF (1.28GeV) Compton scattering may result in a shorter lifetime due to the limited bucket acceptance. We have implemented the effect of Compton scattering on a 2D tracking code with a Monte-Carlo method. This code has been used to study the longitudinal dynamics of the electron beam at the ATF damping ring, in particular the evolution of the energy spread and the bunch length under Compton scattering. The results obtained are presented and discussed. Possible methods to observe the effect of Compton scattering on the ATF beam are proposed.
WEPC052	Spinor Based Calculation of Depolarizing Effects in Circular Lepton Accelerators	2130
	O. Boldt, A. Dieckmann, F. Frommberger, W. Hillert ELSA, Bonn, Germany
	Funding: BMBF The emission of synchrotron radiation strongly influences the beam dynamics in case of ultra relativistic leptons. When storing or accelerating leptons in circular accelerators, the acting magnetic field shows an oscillating behavior in the rest frame of the leptons. Its properties can be determined by a spectral analysis. The stochastic emission of synchrotron light leads to a line broadening within the magnetic field spectrum. This spectrum can be used to simulate depolarizing effects in circular accelerators. Our contribution will present a tracking based calculation of the mentioned spectrum and a spinor-based determination of the resulting population of the spin-up state. These calculations base on the lattice of the electron stretcher accelerator (ELSA, Bonn) and are confirmed by measurements of the polarization.
WEPC053	Crossing of Depolarizing Resonances in Circular Electron Accelerators	2133
	W. Hillert, A. Balling, O. Boldt, A. Dieckmann, F. Frommberger ELSA, Bonn, Germany
	Funding: Supported by the German Research Foundation (DFG) through SFB/TR 16 In flat electron storage rings, only the vertical component of the beam polarization is preserved. During acceleration, the crossing of several depolarizing resonances may cause severe beam depolarization. Even in case of fast ramping speeds of up to 6 GeV/sec, first order effects like imperfection and intrinsic resonances have to be compensated by dedicated measures. At the accelerator facility ELSA, schemes like fast tune jumping and harmonic orbit correction are successfully applied on the fast energy ramp up to 3.2 GeV. Characteristics of the setup as well as the optimization efforts to improve the resonance compensation will be reported in detail.
WEPC054	Amplitude Dependent Tune Spread in the CR Operated as an Antiproton Collector	2136
	A. Dolinskii, C. Dimopoulou, O.E. Gorda, S.A. Litvinov, F. Nolden, M. Steck GSI, Darmstadt, Germany
	The Collector Ring is planned to be built for efficient cooling of antiprotons and rare isotopes beams. In order to accept hot antiproton beams coming from a separator large aperture magnets are required. This paper examines the effects which, may influence on the beam dynamic because of both large both betatron amplitude oscillations (240 mm mrad) and momentum spread (6%). Using analytic expressions the amplitude-dependent tune shifts driven by sextupole magnets, fringe field of quadrupole magnets and kinematics effects have been calculated. The results are compared with numerical simulations. Tracking studies for the CR operated as an antiproton collector have been performed considering the real shape of the magnetic field of the wide aperture quadrupole. We report on quantitative studies of the effects on the tune spread and its influence on the beam losses.
WEPC055	Beam Orbit and Power Converter Stability at the CR	2139
	A. Dolinskii, C. Dimopoulou, O.E. Gorda, S.A. Litvinov, F. Nolden, M. Steck, H. Weick GSI, Darmstadt, Germany
	For the isochronous mode operation of the CR with reference to have good properties of the mass measurements we study the sources of the beam orbit fluctuation and as consequence power converter requirements for the CR operated at BR=13 Tm. This papaer presents a summary of the different factors causing beam orbit variation, which leads to reduction of the mass measurements precision. The requirements to the power converters have been addressed.
WEPC056	Beam Test of Slow Extraction from the ESR	2142
	A. Dolinskii, C. Dimopoulou, O.E. Gorda, S.A. Litvinov, F. Nolden, M. Steck GSI, Darmstadt, Germany
	In the frame of a dedicated ESR machine development the conventional third order resonant slow extraction was theoretically investigated and experimentally tested. The possibility to extract a beam from the ESR by preparing a resonant closed orbit, which has strong nonlinear characteristics, was demonstrated. A third-integer resonance slow extraction has been adopted for the 100 MeV/u Ar beam.
WEPC057	Estimation of the Dynamic Aperture by Transverse Beam Excitation with Noise Close to a Resonance	2145
	S. Sorge, G. Franchetti GSI, Darmstadt, Germany
	The present heavy ion synchrotron SIS-18 will be upgraded to be used as a booster for further synchrotrons being part of the FAIR project underway at GSI. Recently, a method was developed to measure the physical aperture of SIS-18 using transverse RF noise. This method is based on the transverse expansion of the beam with noise beyond the limiting aperture generating beam loss. The aperture was determined from the comparison of the resulting time evolution of the beam current in the machine with that obtained from a numerical simulation. In this study we attempt to apply this method to determine the dynamic aperture of SIS-18.
WEPC058	Field Properties of the ESR Magnets and their Influence on Beam Optics	2148
	O.E. Gorda, C. Dimopoulou, A. Dolinskii, S.A. Litvinov, F. Nolden, M. Steck GSI, Darmstadt, Germany
	Machine experiments at the experimental storage ring (ESR) demonstrated that the ring acceptance is strongly restricted by field errors. Higher-order field harmonics of the dipole and quadrupole magnets have been calculated and then used in particle tracking simulations in order to find out the dynamic aperture of the ESR. To benchmark the results of numerical calculations, betatron tune measurements have been performed with a uranium beam at the energy of 400 MeV/u. The results of the magnetic field simulations for the ESR magnets and a comparison between the measured and calculated tune behavioгr are presented.
WEPC059	Optimization of the Sextupole Scheme and Compensation of the Time-Dependent Field Errors during Slow Extraction from the Superconducting Synchrotron SIS300	2151
	A. Saa Hernandez, P.J. Spiller GSI, Darmstadt, Germany U. Ratzinger IAP, Frankfurt am Main, Germany
	The SIS300 synchrotron, planned for the new Facility for Antiproton and Ion Research (FAIR) at GSI-Darmstadt, will become the first superconducting synchrotron worldwide using cos(θ) magnets for resonant slow extraction. A multi-objective optimization algorithm has been developed for the design of the non-linear magnet scheme. The optimization algorithm makes use of the analytical model for the slow extraction from Kobayashi, the analytical description of the resonance excitation and amplitude-dependent tune-shift from Bengtsson, and corrects the chromaticity in order to fulfill the Hardt condition. As a result, the placement of the chromatic and harmonic sextupole magnets in SIS300, the number of sextupole families and the gradients of these families have been optimized for a high efficiency slow extraction. The algorithm accounts also for the sextupole errors on the dipole magnets, compensating its effects. Furthermore, optimized time-dependent settings for the sextupole magnets are generated to compensate the persistent current decay occurring at slow extraction. Tolerances for the magnets are set for the limits where the compensation is no longer valid.
WEPC060	Magnetic Field Description in Curved Accelerator Magnets using Local Toroidal Multipoles	2154
	P. Schnizer, E.S. Fischer GSI, Darmstadt, Germany B. Schnizer TUG/ITP, Graz, Austria
	Any introduction on beam dynamics describes the field homogeneity of the accelerator magnets using local derivatives. These are then typically described as plane circular multipoles or 2D harmonics; solutions to the potential equation. The high current operation, foreseen for SIS100 accelerator of FAIR, requires an in detail understanding of the different beam effects, driven by the resonance of the magnets. Therefore different multipole sets were developed and are now finalised in the Local Elliptic Toroidal Multipoles. These are a first order approximation while the plane circular ones are a zero order one in the inverse aspect ratio.
WEPC061	ENC Interaction Region Separation Dipoles	2157
	P. Schnizer, E.S. Fischer GSI, Darmstadt, Germany K. Aulenbacher IKP, Mainz, Germany
	The Electron Nucleon Collider (ENC) is proposed as an upgrade of the High Energy Storage Ringe of the FAIR. The beams are separated by two dipoles, mounted closely to the intraction point; surrounded by the detectors. Hence these magnetsmust provide sufficient field quality but be slim to be transparaent to the secondary particles. Further these must be air coil magnets due to the detector solenoid field of 2T. We present the 3D optimised magnet next to a first design of the mechanical restraint structure and a concise description for the field distortion leaking into the detector.
WEPC062	Second Order Achromats with Arbitrary Linear Transfer Matrices	2160
	V. Balandin, R. Brinkmann, W. Decking, N. Golubeva DESY, Hamburg, Germany
	The most obvious method to construct a second order achromat with an arbitrary (predefined) linear transfer matrix is to take a bend magnet system arranged in an achromat like fashion with the total transfer matrix equal to the identity matrix, attach a drift-quadrupole block with the desired linear transfer matrix and then adjust the sextupoles installed in the first part in such a way that the total system becomes a second order achromat. Unfortunately this is not always possible and, in general, the parts of such a system can not be designed independently. In this paper we give the necessary and sufficient conditions which must be satisfied for both parts of the system in order to become a second order achromat. In addition we provide some practical recommendations showing how these conditions can be fulfilled. We formulate these necessary and sufficient conditions using the group-theoretical point of view for the design of magnetic optical achromats as introduced in *. * V. Balandin, R. Brinkmann, W. Decking, N. Golubeva, "Two Cell Repetitive Achromats and Four Cell Mirror Symmetric Achromats", Proc. IPAC'10, Kyoto, Japan (2010).
WEPC063	Apochromatic Twiss Parameters of Drift-quadrupole Systems with Symmetries	2163
	V. Balandin, R. Brinkmann, W. Decking, N. Golubeva DESY, Hamburg, Germany
	It was shown in *, that for every drift-quadrupole system there exists an unique set of Twiss parameters (apochromatic Twiss parameters), which will be transported through that system without first order chromatic distortions. In this paper we investigate apochromatic Twiss parameters of periodic, mirror symmetric and other drift-quadrupole systems with symmetries. * V. Balandin, R. Brinkmann, W. Decking, N. Golubeva, "Apochromatic Beam Transport in Drift-Quadrupole Systems", Proc. IPAC'10, Kyoto, Japan (2010).
WEPC064	Long Term Beam Dynamics in Ultra-Low Energy Storage Rings	2166
	A.V. Smirnov MPI-K, Heidelberg, Germany A.I. Papash, A.V. Smirnov JINR, Dubna, Moscow Region, Russia M.R.F. Siggel-King, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: "Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG-328." Electrostatic storage rings operate at very low energies in the tens of keV range and have proven to be invaluable tools for atomic and molecular physics experiments. However, earlier measurements showed strong limitations in beam intensity, a fast reduction in the stored ion current, as well as significantly reduced beam life time at higher beam intensities and as a function of the ion optical elements used in the respective storage ring. In this contribution, the results from studies with the computer code BETACOOL into the long term beam dynamics in such storage rings, based on the examples of ELISA, the AD Recycler and the USR are presented.
WEPC065	Design of a Low Energy Ion Beam Facility*	2169
	M.R.F. Siggel-King, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom O. Karamyshev JINR/DLNP, Dubna, Moscow region, Russia G.A. Karamysheva MPI-K, Heidelberg, Germany A.I. Papash JINR, Dubna, Moscow Region, Russia M.R.F. Siggel-King The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by STFC, the EU under GA-PITN-215080, the Helmholtz Association and GSI under VH-NG-328. A small electrostatic ring, and associated electrostatic injection beamlines, are being designed and developed. The ring will make possible a variety of experiments using a choice of many types of recirculating ions (e.g., from protons, H-, and antiprotons up to and including large charged biomolecules). A reaction microscope will be incorporated into the ring to enable differential ionization experiments between the recirculating ion beam and gas jet targets. Two injection sections have been designed to cover a variety of ion sources. The facility will be portable to enable it to be moved between facilities and beamlines and it will be unique due to its combination of design elements, flexible beam properties, energy (ca 3-30 keV) and type of circulating particles. In this paper, we give an update on this project.
WEPC066	High Order Non-linear Motion in Electrostatic Rings	2172
	D. Zyuzin, R. Maier, Y. Senichev FZJ, Jülich, Germany
	The advantages of an electrostatic storage ring as compared to a magnetic ring are obvious from the point of view to search for the proton electric dipole moment (pEDM). However the magnetic and electrostatic fields have the different nature and, consequently, different features. In particular, particles moving in electrostatic field, can change their own kinetic energy as electrical field coincides with the direction of motion, which is not so for the magnetic field, where the force is always perpendicular to the direction of motion. The electrostatic rings found many applications in the atomic physics and partly the beam dynamics has been already investigated. However in EDM ring some additional specific features are added, which are considered in this paper.
WEPC067	The Spin Aberration of Polarized Beam in Electrostatic Rings	2175
	Y. Senichev, A. Lehrach, R. Maier, D. Zyuzin FZJ, Jülich, Germany
	For a beam with nonzero transverse emittance and momentum spread passing through an electric field, for example an electric focusing lens or deflector, the orientation of a spin vector becomes a function of 6D initial phase coordinates that leads to spin aberrations. We investigate this process analytically and numerically.
WEPC068	Amplitude Dependent Betatron Oscillation Center Shift by Non-linearity and Beam Instability Interlock	2178
	T. Nakamura, K. Kobayashi, J. Schimizu, T. Seike, K. Soutome, M. Takao JASRI/SPring-8, Hyogo-ken, Japan T. Hara RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	The center of the betatron oscillation in storage rings shifts as the amplitude of the oscillation increases. This effect is produced by non-linear components like sextupole magnets with its first-order perturbation. This shift can be observed as the shift of the closed orbit with usual slow beam position monitor (BPM) for closed orbit measurement. At the SPring-8 storage ring, the insertion devices (IDs) have their dedicated BPMs for monitoring the beam axis in the IDs. If some amount of the shift of beam axis is observed, the beam is aborted to avoid the damage by the irradiation of the ring components by ID radiation. When a betatron oscillation is excited by a beam transverse instability, the beam axis also oscillates and might produce the damage. Though it is not easy to detect the oscillation amplitude in various bunch current and filling patterns like in SPring-8, the oscillation produces the shift of the center of the betatron oscillation and can be observed by the BPM of IDs, and the beam is aborted. Calculation, tracking simulation and observation will be reported.
WEPC069	Impact of Nonlinear Resonances on Beam Dynamics at the SPring-8 Storage Ring	2181
	M. Takao, J. Schimizu, Y. Shimosaki, K. Soutome JASRI/SPring-8, Hyogo-ken, Japan
	For a low emittance storage ring like high brilliant light sources, the improvement of nonlinear beam dynamics is necessary for the stable operation, or for providing large dynamic aperture and momentum acceptance for efficient injection and long Touschek lifetime. At the SPring-8 storage ring it is observed that injection efficiency is affected by the gap heights of the magnet arrays of the in-vacuum insertion devices. The fact that the injected beam of fundamentally oscillating in horizontal direction is limited by the vertical aperture means that coupling resonances influence the beam dynamics. To clarify the phenomena, we studied the nonlinear beam dynamics of transverse betatron motion by means of turn-by-turn method. Then, we found some nonlinear coupling resonances, such as the one by skew sextupole field, are excited to enhance vertical oscillation and to deteriorate the injection efficiency. By analyzing these results, we developed measures to suppress the effect of the nonlinear coupling resonances and to improve the injection efficiency.
WEPC071	The Motion of an Electron in the Periodic Cusped Magnetic Fields	2184
	G. Du, B.L. Qian, H. Wang National University of Defense Technology, Changsha, Kaifu District, People's Republic of China
	Funding: National High Technology Research and Development Program of P. R. China The motion and its stability of an electron in the periodic cusped magnetic fields have been analyzed theoretically and calculated numerically, as the stability could not be well predicted by the Mathieu’s equation to guide the design of the magnetic focusing system for the propagation of the sheet electron beams in the waveguides. The precise solution to the motion equations of the electron has been obtained by iteration. To validate the analytical solution and to evaluate the stability of the motion, numerical calculations have been carried out. And the results show that the analytical solution is reliable, and there is only one stable region in the (p0, B0) space, where the parameter p0 is the period of the magnetic fields, and B0 is the magnitude of the magnetic fields. Besides, the stability of the electron motion would become weaker while the initial distance between the electron and the axis becomes larger. These results are interesting to the area of the sheet-electron-beam microwave sources focused by the periodical cusped magnetic fields.
WEPC072	Insertion Devices and Beam Dynamics in the PLS-II Storage Ring	2187
	S. Chunjarean, S. Shin PAL, Pohang, Kyungbuk, Republic of Korea
	Effects of insertion devices like a superconducting multipole wiggler or an in-vacuum undulator on the beam dynamics of tghe upgraded Pohang Light Source (PLS-II) storage ring have been investigated. The narrow gap related to a short period length of the in-vacuum undulator or a transverse magnetic field roll off can impact the dynamic aperture or Touschek lifetime or injection efficiency. A three dimensional magnetic field model has been developed based on numerical data consisting of several coefficients in the Taylor expansion to accurately represent the actual field. In this paper, the magnetic field model has been produced with the differential algebraic code COSY INFINITY to formulate the Taylor transfer map for the wiggler and undulator. Frequency map analysis (FMA) and full 6D tracking has been performed to investigate resonances which may affect the particle stability and causing a reduction in injection efficiency.
WEPC074	Investigation of the Nonlinear Transformation of an Ion Beam in the Plasma Lens*	2190
	N.N. Alexeev, A.A. Drozdovsky, S.A. Drozdovsky, A. Golubev, Yu.B. Novozhilov, P.V. Sasorov, S.M. Savin, V.V. Yanenko ITEP, Moscow, Russia
	The plasma lens can carry out not only sharp focusing of ions beam. At those stages at which the magnetic field is nonlinear, formation of other interesting configurations of beams is possible. Plasma lens provides formation of hollow beams of ions in a wide range of parameters*. Application of the several plasma lenses allow to create some nontrivial spatial configurations of ions beams**: to get a conic and a cylindrical beams. The plasma lens can be used for transformation of beams with Gaussian distribution of particles density in a beams with homogeneous spatial distribution. The calculations showed that it is possible for a case of equilibrium Bennett's distribution of a discharge current. This requires a long duration of a discharge current pulse of > 10 μs. The first beam tests have essentially confirmed expected result. Calculations and measurements were performed for a C+6 and Fe+26 beams of 200-300 MeV/a.u.m. energy. The obtained results and analysis are reported. * A. Drozdovskiy et al., IPAC'10, Kioto, Japan, http://cern.ch/AccelConf/IPAC10 /MOPE040. ** A.Drozdovskiy et al., RUPAC’10, Protvino, Russia, http://cern.ch/AccelConf/RUPAC10 /THCHA01.
WEPC075	ITEP-TWAC Progress Report	2193
	N.N. Alexeev, P.N. Alekseev, V. Andreev, A. Balabaev, V.I. Nikolaev, A.S. Ryabtsev, Yu.A. Satov, V.A. Schegolev, B.Y. Sharkov, A. Shumshurov, V.P. Zavodov ITEP, Moscow, Russia
	The program of the ITEP-TWAC Facility upgrade for next three years has been approved last year in the frame of National Research Center Kurchatov Institute taking up ITEP in accordance with government decision. It includes expanding of multimode using proton and heavy ion beams in different applications on a base of new accelerator technologies development. The laser ion source advantage of high temperature plasma generation has to be transformed to high current and high charge state ion beam of Z/A up to 0.4 for elements with A ~ 60 to be effectively stacked in the accumulator ring with multiple charge exchange injection technique. The new high current heavy ion RFQ section is in progress for the beam test. Accelerating system of accumulator ring U-10 is modified to increase compression voltage for stacked beam by factor of four. Design of proton injection and beam slow extraction for UK ring is performed for its utilizing as self-depending synchrotron in medical application and for imitation of cosmic radiation. The machine status analysis and current results of activities aiming at both subsequent improvement of beam parameters and expanding beam applications are presented.
WEPC077	Beam Based Measurements with the Modified Wigglers in DAΦNE	2196
	S. Bettoni CERN, Geneva, Switzerland A. Drago, S. Guiducci, C. Milardi, M.A. Preger, P. Raimondi INFN/LNF, Frascati (Roma), Italy
	A novel idea to minimize the odd high order non-linearities in periodic magnets has been presented in other articles in the past. The optimization of this method on the wigglers of the main rings in DAΦNE has been performed by means of multipolar and tracking analysis. After the magnetic measurements on a spare wiggler confirmed the magnetic model used to optimize the DAΦNE wigglers, all the insertion devices in the main rings have been modified accordingly. In fall last year tune variation measurements as a function of closed orbit bumps around the wigglers confirmed the validity of the method. In this paper the beam based measurement results with the new configuration are discussed and compared with those obtained in the previous configurations.
WEPC078	Non-linear Chromaticity Studies of the LHC at Injection	2199
	E.H. Maclean, M. Giovannozzi, F. Schmidt, R.J. Steinhagen, E. Todesco, R. Tomás, G. Vanbavinckhove CERN, Geneva, Switzerland R. Bartolini JAI, Oxford, United Kingdom
	The non-linear chromaticity of the LHC has been studied. Measurements of variation in tune with dp/p on both beams at injection optics are being compared with Q'' and Q''' as calculated with the LHC effective model. This model uses the best currently available measurements of magnetic field harmonics. An attempt is being made to optimize the b4 and b5 pool-pieces corrections in view of the corresponding chromaticity terms.
WEPC079	Beta-beating in the Effective Model of the LHC Using PTC	2202
	M.C. Alabau Pons, F. Schmidt, R. Tomás CERN, Geneva, Switzerland E.H. Maclean JAI, Oxford, United Kingdom
	An effective model of the LHC optics has been developed based on measurements of magnetic field, alignment errors and closed orbit. This model utilizes the Polymorphic Tracking Code with MAD-X as front-end to allow the inclusion of harmonics to an arbitrary order in thick lattice elements. Beta-beating calculations have been performed with this model at injection optics and at 3.5 TeV squeezed optics to 3.5 m beta-function at the interaction point. The model predictions are in remarkable agreement with the measurements performed in the 2010 LHC commissioning run.
WEPC080	Non-linear Dynamics Optimization of the CLIC Damping Rings	2205
	Y. Renier, F. Antoniou, H. Bartosik, Y. Papaphilippou CERN, Geneva, Switzerland K.P. Wootton The University of Melbourne, Melbourne, Australia
	Non-linear dynamics studies are undertaken in order to optimize the dynamic aperture of the CLIC damping rings. In this respect, advanced methods such as frequency map and resonance driving term analysis are used in order to explore the working point space with respect to single particle stability. The impact of magnet errors and misalignments, and in particular, the effect of the super-conducting damping wigglers is evaluated. Additional considerations for the working point choice are presented.
WEPC081	Beam-Beam Induced Orbit Effects at LHC	2208
	M. Schaumann, R. Alemany-Fernandez CERN, Geneva, Switzerland
	For high bunch intensities the beam-beam force is strong enough to expect orbit effects if the two beams do not collide head-on but with a crossing angle or with a given offset. As a consequence the closed orbit changes. The closed orbit of an unperturbed machine with respect to a machine where the beam-beam force becomes more and more important has been studied and the results are presented in this paper.
WEPC085	Multipole Fringe Fields	2211
	B.D. Muratori, J.K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom M.J. de Loos, S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	When creating an initial model of an accelerator, one usually has to resort to a hard edge model for the quadrupoles and higher order multipoles at the start of the project. Ordinarily, it is not until much later on that one has a field map for the given multipoles. This can be rather inconvenient when one is dealing with particularly thin elements or elements which are rather close together in a beamline as the hard edge model may be inadequate for the level of precision desired. For example, in the EMMA project, the two types of quadrupoles used are so close together that they are usually described by a single field map or via hard edge models. The first method has the desired accuracy but was not available at the start of the project and the second is known to be a rough approximation. In this paper, an analytic expression is derived and presented for fringe fields for a multipole of any order with a view to applying it to cases like EMMA.
WEPC087	Dark Current Simulations for the Cornell ERL	2214
	C.E. Mayes, C.S. Chiu, G.H. Hoffstaetter, V.O. Kostroun, D. Sagan CLASSE, Ithaca, New York, USA L.M. Nash North Carolina University, Chapel Hill, North Carolina, USA
	Funding: Supported by NSF award DMR-0807731 Charged particles unintentionally transported through an accelerator, collectively called the dark current, can be lost in the beam chamber and create a radiation hazard for both equipment and personnel. Here we simulate the creation of particles by field emission in the superconducting accelerating cavities of the Cornell Energy Recovery Linac, and track them to their loss points. These lost particles can then be used to simulate background radiation. The presented calculations are therefore an essential step in the design of appropriate radiation-shielding of components around the linac.
WEPC088	Embedding Finite Element Results for Accelerator Components in a Moment Approach Beam Dynamics Code*	2217
	T. Roggen, H. De Gersem, B. Masschaele KU Leuven, Kortrijk, Belgium W. Ackermann, S. Franke, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This research is funded by grant ''KUL 3E100118'' ''Electromagnetic Field Simulation for Future Particle Accelerators''. A moment based beam dynamics code has particular advantages, i.e. accuracy and efficiency, over macro-particle tracking and full particle-in-cell (PIC) codes respectively. Instead of embedding analytical descriptions of the accelerator components in the beam dynamics model, it is proposed to insert a surrogate model obtained from the finite element model of individual accelerator components. We apply the V-Code, which accepts moments up to the sixth order and accounts for space charge effects. We construct and calculate finite element and finite difference time domain models using the CST Studio Suite 2011 software package. An interface is implemented using VBA and MATLAB. As an example of the accuracy of this cascadic simulation approach, we compare the beam dynamics of an S-DALINAC quadrupole obtained by directly tracking particles to the calculated fields with the results for the cascadic approach with the V-Code. This work was performed during a three month research visit at the Technische Universität Darmstadt, Institut für Theorie Elektromagnetischer Felder, Darmstadt, Germany.
WEPC091	Studies with a Particle Tracking Code for the SIS100 Resonant Extraction System	2220
	M.M. Kirk, G. Franchetti, H. Klingbeil, P. Moritz, N. Pyka, H. Ramakers, P.J. Spiller, H. Welker GSI, Darmstadt, Germany
	Several issues concerning the envisaged SIS100 resonant extraction at GSI can be resolved with a simulation-lead approach for which a particle tracking code was developed. Applications to date have included: design and testing of data supply algorithms for the accelerator control system; requirements analysis for the power converter ripple in the quadrupoles forming the doublet focusing; and verification of the RF Knock-Out exciter's performance.
WEPC092	Moment-Based Simulation of the S-DALINAC Recirculations*	2223
	S. Franke, W. Ackermann, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany R. Eichhorn, F. Hug, C. Klose, N. Pietralla, M. Platz TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by DFG under contract SFB 634. The Superconducting Linear Accelerator S-DALINAC installed at the institute of nuclear physics (IKP) at TU Darmstadt is designed as a re-circulating linear accelerator. The length of the beam line and the numerous accelerating structures as well as dipole and quadrupole magnets require a highly efficient numerical simulation tool in order to assist the operators by providing a detailed and almost instantaneous insight into the actual machine status. A suitable approach which enables a fast online calculation of the beam dynamics is given by the so-called moment approach where the particle distribution is represented by means of a discrete set of moments or by multiple discrete sets of moments in a multi-ensemble environment. Following this approach the V-Code simulation tool has been implemented at the Computational Electromagnetics Laboratory (TEMF) at TU Darmstadt. In this contribution an overview of the numerical model is presented together with new V-Code simulation results regarding the S-DALINAC recirculation sections.
WEPC093	Various Approaches to Electromagnetic Field Simulations for RF Cavities	2226
	C. Liu, W. Ackermann, W.F.O. Müller, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by BMBF under contract 05H09RD5 In the Superconducting Proton Linac (SPL) cavity, there is not only the fundamental mode for the particle acceleration but also many higher order modes (HOMs), which can lead to particle beam instabilities. This is very dangerous for SPL cavity. Therefore it is necessary to simulate the electromagnetic field in the SPL cavity, so that the field distribution and the shunt impedance for every higher order mode can be precisely calculated. At TEMF this research work can be done in three different ways: field simulation with hexahedron mesh in frequency domain, field simulation with hexahedron mesh in time domain and field simulation with tetrahedral mesh and higher order curvilinear elements. Finally the HOM coupler will be considered for the effective damping of higher order modes in the SPL cavity.
WEPC094	Energy Loss and Longitudinal Wakefield of Relativistic Short Ion Bunches in Electron Clouds	2229
	F. Yaman, O. Boine-Frankenheim, E. Gjonaj, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany G. Rumolo CERN, Geneva, Switzerland
	Funding: Work supported by BMBF under contract 06DA9022I The aim of our study is the numerical computation of the wakefield, impedance and energy loss for an energetic, short (< 10 ns) ion bunch penetrating an electron cloud plasma residing in the beam pipe. We use a 3-D self-consistent and higher order PIC code based on the full-wave solution of the Maxwell equations in the time domain. In our simulations we observe the induced density oscillations in the electron cloud in the longitudinal as well as in the transverse directions. A special numerical procedure is applied to compute the longitudinal wake potential and the broadband coupling impedance due to the beam-electron cloud interaction. The code is applied to the case of the CERN SPS and the projected SIS-100 at GSI. The effects of the beam pipe, electron density, bunch intensity and external magnetic dipole fields are studied. The results are compared to analytical and numerical models of reduced complexity.
WEPC095	Simulations of the Microbunching Instability at ANKA using a Vlasov-Fokker-Planck Solver	2232
	M. Klein, A.-S. Müller KIT, Karlsruhe, Germany K.G. Sonnad CLASSE, Ithaca, New York, USA
	In order to produce coherent synchrotron radiation the ANKA light source is operated frequently in short bunch mode. It is known that during this procedure strong self fields caused by high electron densities can enforce initial density fluctuations and thus lead to microbunching. The build-up of those substructures is accompanied by bursting radiation which provides higher radiation power for the users. Damping and diffusion due to incoherent radiation smoothens the bunch shape again and hence lead to periodic or chaotic bursting cycles. The evolution of the electron bunch density under the influence of self fields can be described by the Vlasov-Fokker-Plank (VFP) equation. We present results from a numerical solution of the VFP-equation for parameters used in standard short bunch mode at ANKA.
WEPC096	Calculation of High Frequency Fields in Resonant Cavities Based on Perturbation Theory*	2235
	K. Brackebusch, H.-W. Glock, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Work supported by Federal Ministry for Research and Education BMBF under contracts 05H09HR5 and 05K10HRC. The knowledge of the eigenmodes of resonant accelerator cavities is essential for the determination of their performance characteristics, comprising resonant frequencies and field distributions inside the cavities. Apart from the material properties the eigenmodes of a cavity depend on its geometry. In spite of the high elaborateness during the complex fabrication process, minor deviations of the actual cavity shape from the desired one are inevitable. Moreover, especially superconducting cavities are subject to extreme operating conditions that may cause deformations of their shape. Any geometry perturbation results in a shift of the resonant frequencies and modified field distributions. In this paper, we will analyze a generalization of Slater's theorem proposed in literature. The method should allow for the calculation of resonant frequencies and field distributions of a slightly perturbed cavity by using a set of precomputed eigenmodes of the unperturbed cavity. We will evaluate the practicability of the method by applying it to cavity geometries for which the eigenmodes are analytically known, ascertain the effort of reasonable calculation results and describe its limitations.
WEPC097	A Concatenation Scheme for the Computation of Beam Excited Higher Order Mode Port Signals	2238
	T. Flisgen, H.-W. Glock, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Ongoing studies investigate in how far higher order mode (HOM) port signals of superconducting RF cavities can be used for machine and beam diagnostics. Apart from experiments e.g. at the FLASH facility at DESY in Hamburg, numerical modelling is needed for the prediction of HOM coupler signals. For this purpose, the RF properties of the entire accelerating module have to be taken into account, since higher order modes can propagate along the cavity chain. A discretization of the full chain, followed by a wake field simulation is only feasible with powerful and expensive cluster computers. Instead, an element wise wake field simulation of sub-sections of the chain, followed by a suitable concatenation scheme can be performed on standard hardware assuming the beam to be sufficiently stiff. In this paper a concatenation scheme for the computation of beam excited HOM port signals is derived as a generalization of the Coupled S-Parameter scheme CSC. Furthermore, the validity of the method is shown for a sample structure.
WEPC098	Automatic Pole and Q-Value Extraction for RF Structures	2241
	C. Potratz, H.-W. Glock, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany F. Marhauser JLAB, Newport News, Virginia, USA
	The experimental characterization of RF structures like accelerating cavities often demands for measuring resonant frequencies of Eigenmodes and corresponding (loaded) Q-values over a wide spectral range. A common procedure to determine the Q-values is the -3dB method, which works well for isolated poles, but may not be applicable directly in case of multiple poles residing in close proximity (e.g. for adjacent transverse modes differing by polarization). Although alternative methods may be used in such cases, this often comes at the expense of inherent systematic errors. We have developed an automation algorithm, which not only speeds up the measurement time significantly, but is also able to extract Eigenfrequencies and Q-values both for well isolated and overlapping poles. At the same time the measurement accuracy may be improved as a major benefit. To utilize this procedure merely complex scattering parameters have to be recorded for the spectral range of interest. In this paper we present the proposed algorithm applied to experimental data recorded for superconducting higher-order-mode damped multi-cell cavities as an application of high importance.
WEPC099	Coupler Design and Optimization by GPU-Accelerated DG-FEM	2244
	C. Potratz, H.-W. Glock, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	The numerical optimization of rf-components like couplers is a common task during the design phase of particle accelerators. Typically, these optimizations involve the simulation of a multitude of very similar structures with minor geometric variations. Nevertheless, this process is in its entire extend rather demanding on both the invested time and hardware budget. With recent advancements in the field of numerical electromagnetic field simulation and consumer graphic processors, an interesting alternative for the time-consuming simulation part of the optimization is available. In this contribution we show, how the Discontinuous Galerkin FEM method in conjunction with consumer graphic cards can be used to build moderately prized cluster solutions for the parallel simulation of rf-components. The contribution will mainly focus on, but is not limited to, Higher Order Mode couplers as a typical application example, where the DG-FEM method accelerated by a graphic processor might be used to significantly reduce the overall time necessary for the optimization.
WEPC100	Simulation of the Single Bunch Instability due to the Electron Cloud Effect by Tracking with a Pre-computed 2D Wake Matrix*	2247
	A. Markoviḱ, G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Supported by DFG Contract Nr. RI 814/20-1. The passage of a positron bunch through an initially homogeneous electron cloud (e-cloud) changes the distribution of the e-cloud in a way that the concentration of electrons in the proximity of the beam axis grows rapidly. The electrons are primarily moving in the transverse plane and are very sensitive on the beam centroid position in that plane. Thus the transverse kick of the e-cloud on the tail particles depends on the centroid position of the head particles of the same bunch. A PIC simulation of the interaction of a positron beam with an e-cloud yields the wake kick from the electrons on the tail particles for a certain offset in the transverse centroid position of the head parts of the bunch. With such a pre-computed 2D wake matrix, for a certain e-cloud density, we investigate the stability of a single bunch by tracking it through the linear optics of the storage ring while at each turn applying the kick from the e-cloud. We examine the positron bunch stability of KEKB-LER and PETRAIII for a certain electron cloud density.
WEPC101	Simulation of the Interaction of an Electron Beam with Ionized Residual Gas	2250
	G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany A. Meseck HZB, Berlin, Germany
	Funding: Supported by BMBF under contract number 05K10HRC Light sources of the next generation such as ERLs require minimal beam losses as well as a stable beam position and emittance over the time. Instabilities caused by ion accumulation have to be avoided. In Rostock the tracking code MOEVE PIC Tracking has been developed for the simulation of space charge influenced beam dynamics, which is recently applied for simulations of the interaction beam - e-cloud. In this paper we apply MOEVE PIC Tracking for simulation of the interaction of the ionized residual gas with an electron bunch. We demonstrate numerical results with parameters planed for the ERL BERLinPro.
WEPC102	Recent Developments for Efficient 3D Space Charge Computations Based on Adaptive Multigrid Discretizations	2253
	G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany M.J. de Loos TUE, Eindhoven, The Netherlands S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	Funding: Partly supported by BMBF under contract number 05K10HRC Efficient and accurate space-charge computations are essential for the design of high-brightness charged particle sources. Recently a new adaptive meshing strategy based on multigrid was implemented in GPT and the capabilities were demonstrated. This new meshing scheme uses the solution of an intermediate step in the multigrid algorithm itself to define optimal mesh line positions. In this paper we discuss further developments of this adaptive meshing strategy. We compare the new algorithm with the current meshing scheme of GPT, where the mesh line positions are based upon the projected charge density.
WEPC104	Vicky : A Computer Code for Use in the Design and Simulation of Particle Accelerators	2256
	F. Iazzourene ELETTRA, Basovizza, Italy
	Vicky is a computer code under development for designing and simulating particle accelerators. Like other existing codes, the features include machine imperfections, closed orbit correction, Twiss functions matching, chromaticity evaluation and correction, particle tracking and so on. The goal is to give the users a friendly graphical interface with widgets to perform the wished tasks, for example to plot the orbit, the Twiss functions, the tune diagram, the dynamic aperture and so on, to select and read an input file describing the considered lattice, to perform the Twiss functions matching, a closed orbit correction and so on. The code provides a description of the particle motion by 10 parameters: four beta-functions, four alpha-functions and two phase advances, that is a 4*4 generalized transverse coupling, together with an emphasis on the treatment of the complex 3D magnetic fields of the undulators used in today’s modern synchrotron radiation facilities. The code is written in C++. It uses the free packages QT for the online plots and the graphical user interface and IT++ for the mathematics. The present status and some results of its application will be presented.
WEPC105	Multiparticle Simulation of Intrabeam Scattering for SuperB	2259
	T. Demma, M.E. Biagini, M. Boscolo INFN/LNF, Frascati (Roma), Italy K.L.F. Bane, A. Chao, M.T.F. Pivi SLAC, Menlo Park, California, USA
	Intrabeam scattering (IBS) is associated with multiple small angle scattering events leading to emittance growth. In most electron storage rings, the growth rates arising from IBS are much longer than damping times due to synchrotron radiation, and the effect on emittance growth is negligible. However, IBS growth rates increase with increasing bunch charge density, and for storage rings such as SuperB, that operate with high bunch charges and very low vertical emittance, the IBS growth rates can be large enough to produce significant emittance increase. Several formalisms have been developed for calculating IBS growth rates in storage rings*. However these models, based on Gaussian bunch distributions, cannot investigate some interesting aspects of IBS such as its evolution during the damping process and its effect on the beam distribution. We developed a multiparticle tracking code, based on the Binary Collision Model**, to investigate these effects. In this communication we present the structure of the code and simulation results obtained with particular reference to the SuperB parameters. Simulation results are compared with those of conventional IBS theories. * A. Piwinski, Lect. Notes Phys. 296 (1988); J.D. Bjorken and S.K. Mtingwa, Part. Accel. 13 (1983); K. Kubo et al., Phys. Rev. ST-AB 8 (2005). ** Peicheng Yu et al., Phys. Rev. ST–AB 12 (2009).
WEPC106	Touschek Effect at DAΦNE for the New KLOE Run in the Crab-Waist Scheme	2262
	M. Boscolo, P. Raimondi INFN/LNF, Frascati (Roma), Italy E. Paoloni University of Pisa and INFN, Pisa, Italy A. Perez INFN-Pisa, Pisa, Italy
	Funding: Work supported by the EuCARD research programme within the 'Assessment of Novel Accelerator Concepts' work package (ANAC-WP11) The innovative crab-waist collision scheme has been recently implemented at DAΦNE for a new KLOE run. This scheme requires special attention to the Touschek effect, both for the lifetime and the machine induced backgrounds into the detector. These two aspects have been handled starting from the same Monte Carlo simulation. The DAΦNE optical model has been tuned to keep the effects of Touschek scattering under control with a trade-off between critical parameters, following the indications given by simulations. Connections between numerical results and lattice modifications are discussed here. Dedicated lifetime measurements have been carried out to validate these studies. Particle losses at the IR have been minimized by means of the same optical knobs, but in addition proper shieldings have been implemented to further decrease their impact on the detector performance. IR distributions of the Touschek particle losses have been tracked from the beam pipe into KLOE for direct comparison of measured and expected backgrounds. Moreover, these studies are carried out with the same software tools used for the SuperB factory design, allowing a direct validation test of this approach.
WEPC107	Development of a Steady State Simulation Code for Klystron Amplifiers	2265
	C. Marrelli CERN, Geneva, Switzerland M. Migliorati, A. Mostacci, L. Palumbo Rome University La Sapienza, Roma, Italy B. Spataro INFN/LNF, Frascati (Roma), Italy S.G. Tantawi SLAC, Menlo Park, California, USA
	The design of klystrons is based on the intensive utilization of simulation codes, which can evaluate the complete beam-cavities interaction in the case of large signals. In the present work, we present the development of a 2-D steady state simulation code that can self-consistently evaluate the effects of the electromagnetic field on the particles and of the particles back on the field. The algorithm is based on the iterative solution of the power balance equation in the RF structures and allows determining the amplitude and phase of the electromagnetic field starting from the cavity modes. Some applications of the code to a single cavity and a two cavity klystron are presented and compared with the results obtained from other codes. The effect of the space charge forces in the klystron drift tubes is also evaluated.
WEPC108	CSR Impedance for an Ultrarelativistic Beam moving in a Curved Trajectory	2268
	D.M. Zhou, K. Ohmi, K. Oide KEK, Ibaraki, Japan
	A dedicated computer code, CSRZ, has been developed to calculate the coherent synchrotron radiation (CSR) impedance for an ultrarelativistic beam moving in a curved trajectory. Following the pioneering work of T. Agoh and K. Yokoya*, the code solves the parabolic equation in the frequency domain in a curvilinear coordinate system. The beam is assumed to move along a vacuum chamber which has a uniform rectangular cross section but with variable bending radius. Using this code, we did investigations in calculating the longitudinal CSR impedance of a single and a series of bending magnets. The calculation results indicate that the shielding effect due to outer chamber wall can be well explained by a simple optical approximation model at high frequencies. The CSR fields reflected by the outer wall may interfere with each other in a long bending magnet and lead to sharp narrow peaks in the CSR impedance. * T. Agoh and K. Yokoya, Phys. Rev. ST Accel. Beams, 7(5):054403 (2004).
WEPC109	Emittance Optimization Using Particle Swarm Algorithm*	2271
	Z. Bai, W. Li, L. Wang USTC/NSRL, Hefei, Anhui, People's Republic of China
	In this paper we use a swarm intelligence algorithm, particle swarm optimization (PSO), to optimize the emittance directly. Some constraint conditions such as beta functions, fractional tunes and dispersion function, are considered in the emittance optimization. We optimize the strengths and positions of quadrupoles to search low emittances. Here an FBA lattice studied in the design of the Hefei Advanced Light Source storage ring is used as the testing lattice. The PSO is shown to be beneficial in the optimization.
WEPC111	Single Particle Tracking Simulation for Compact Cyclotron*	2274
	H.W. Kim, J.-S. Chai, B.N. Lee, Y.S. Lee, K.R. Nam, H.S. Song SKKU, Suwon, Republic of Korea
	Funding: Ministry of Education, Science and Technology, Republic of Korea. Department of Energy Science and School of Information and Communication Engineering of SungKyunKwan University. Low energy compact cyclotrons for Positron emission tomography (PET) are needed for the production of radio-isotope. In the magnet design for those cyclotrons, single particle tracking simulation after the design is important to check the quality of designed magnetic field of the magnet. The study of single particle tracking simulation for cyclotron magnet is shown in this paper. Maximum beam energy of example cyclotron is 9 MeV for proton and pseudo accelerating gap is adapted for the simulation. 3D CAD program CATIA P3 V5 R18 is used for design the magnet and pseudo accelerating gap. All magnetic and electric field calculations had been performed by OPERA-3D TOSCA and the own-made program OPTICY is used for other calculations - phase slip, radial and axial tune.
WEPC114	Covariant Formulation of the Vlasov Equation	2277
	O.I. Drivotin St. Petersburg State University, St. Petersburg, Russia
	In traditional approach, the Vlasov equation is considered as integro-differential equation. That formulation includes partial derivatives on phase coordinates. According to the covariant approach, physical relations should be presented by tensor equations. The main feature of the covariance is that any tensor equation can be written without using of coordinates. In covariant formulation of the Vlasov equation, we use such tensor objects as Lie derivatives. Classical and relativistic cases are described similarly. A difference between these two cases appears only in form of particle motion equations. Another feature of presented approach is consideration of degenerate distributions in the phase space. By degenerate distribution we mean a distribution having support of dimension smaller than dimension of the phase space. The simplest case of degenerate distribution is the distribution described by the Dirac measure. Another example is the Kapchinsky-Vladimirsky distribution, for which particles are distributed on the 3-dimensional surface in the 4-dimensional phase space.
WEPC115	A Global Optimization Approach Based on Symbolic Presentation of a Beam Propagator	2280
	S.N. Andrianov, A.N. Ivanov, M. Kosovtsov, E.A. Podzyvalov St. Petersburg State University, St. Petersburg, Russia
	It is known that modern systems of beam lines consist of huge control elements even in the case of small machines. The problem of the beam line design leads us to formulate this problem as a global optimization ones. This approach allows us defining a family of appropriate solutions. On the next steps a researcher should narrow this optimal solutions set using additional methods and concepts. The symbolic presentation of necessary information plays leading role on all steps of the suggested approach. The corresponding implementation presented in the paper allows us to find the optimal sets in parameters spaces in a proper way. The corresponding applied software was used for solution of some practical probems. The described ideology implies to use distributed and parallel technologies for necessary computing and will be integrated in the Virtual Accelerator concept.
WEPC116	A Matrix Presentation for a Beam Propagator including Particles Spin	2283
	M. Kosovtsov, S.N. Andrianov, A.N. Ivanov St. Petersburg State University, St. Petersburg, Russia
	Particles beam dynamics in magnetic and electrical fields with spin is discussed. This approach provides a constructive method of matrix presentation derivation for a beam propagator in magnetic and electrical fields. The beam propagator is evaluated in according to the well-known Lie algebraic tools. But in contrast to traditional approaches matrix presentation for Lie propagators bases on two-indexes matrices. This approach permit to apply all of matrix algebra opportunities and advantages in contrast with the tenzor presentation based on multi-indexes description. The necessary computation can be realized in symbolic (using computer algebra codes as Mathematica, Maple, Maxima and so on). The corresponding symbolic objects itself can be stored in special databases and used then in numerical computing. Parallel and distributed conception is well acceptable with the suggested matrix formalism. Some symbolic and numerical results are discussed for problems of long term evolution of particles with spin.
WEPC117	Symmetry Based Design for Beam Lines*	2286
	S.N. Andrianov, A.N. Ivanov, M. Kosovtsov St. Petersburg State University, St. Petersburg, Russia
	Usually, the beam line design problems are solved using numerical optimization methods (for example, in the frame of so called global optimization paradigm). But this approach demonstrates enough effectiveness only after sufficient reduction of a control parameters set. In this paper we present the symmetry design concept based on symbolic computations for the corresponding beam line propagator. The combination of symbolic algebra codes (such as Maple, Mathematica, Maxima and so on) with the matrix formalism for Lie algebraic tools enables us to carry out the entire theoretical and computing processes for design of the beam line under study. For this purpose some of necessary physical requirements are formulated in the terms of the corresponding symmetry conditions. The suggested approach can be realized in both exact and approximate forms of the symmetry terms. The found conditions can sufficiently reduce the number of control parameters for the next optimization step.
WEPC119	PYMAD – Integration of MADX in PYTHON	2289
	K. Fuchsberger, Y.I. Levinsen CERN, Geneva, Switzerland
	The de-facto standard software for modeling accelerator lattices at CERN is MADX (Methodical Accelerator Design), which is implemented and still maintained in the programming languages C and FORTRAN. For detailed processing, analysis and plotting of MADX results, other programming languages are often used. One very popular scripting language is PYTHON, which is widely used in the physics community and provides powerful numerical libraries and plotting routines. Therefore, access to MADX models from PYTHON is a common demand. Currently, several possible concepts for the realization of such a project are evaluated, including direct access to MADX via CYTHON (C extension of PYTHON) or the re-usage of the existing JMAD Java libraries, benefiting from the already available model-definitions. A first prototype is already in use and the release as an open source project is in preparation. This paper presents the concepts and the current status of the project, as well as some usage examples.
WEPC120	Status of JMAD, the JAVA-API for MADX	2292
	K. Fuchsberger, X. Buffat, Y.I. Levinsen, G.J. Müller CERN, Geneva, Switzerland
	MADX (Methodical Accelerator Design) is the de-facto standard software for modeling accelerator lattices at CERN. This feature-rich software package is implemented and still maintained in the programming languages C and FORTRAN. Nevertheless the controls environment of modern accelerators at CERN, e.g., of the LHC, is dominated by JAVA applications. A lot of these applications, for example, for lattice measurement and fitting, require a close interaction with the numerical models, which are all defined by the use of the proprietary MADX scripting language. To close this gap an API to MADX for the JAVA programming language (JMAD) was developed. JMAD was first presented to the public about one year ago. In the meantime, a number of improvements were done, and additional MADX features (e.g., tracking) were made available for JAVA applications. Additionally, the graphical user interface was improved, and the first release as open source software is in reach. This paper describes the current status and some new features of the project, as well as some usage examples.
WEPC121	XML Constructs for Developing Dynamics Applications or Towards a Universal Representation of Particle Accelerators in XML	2295
	J.T.M. Chrin, R.A. Krempaska, H. Lutz, G. Prekas PSI, Villigen, Switzerland T.A. Pelaia ORNL, Oak Ridge, Tennessee, USA
	A recognized practice within the development of high-level beam dynamics applications is to separate data parameters destined for the configuration of the application from the programming language domain. The contemporary approach is to generate input files that provide the configuration parameters in a structured data format specified by the Extensible Markup Language (XML), enhancing flexibility and simplifying code maintenance. Furthermore, a careful choice of syntactic constructs, i.e. structured elements, attributes, etc., that map well to the various accelerator components, provides a basis for portability of applications. This has been exemplified by the XAL software package which initiated an XML description of the Standard Machine Format (SMF) accelerator object model. We have since adopted XML-SMF to provide an XML representation of both the Swiss Light Source (SLS) and the SwissFEL Injector Test Facility. We demonstrate how such XML constructs allow us to deploy the same orbit display application at both facilities. Our experience leads us to advocate a Universal Machine Format (UMF) that encompasses an all-inclusive XML schema for the management of accelerator information.
	Poster WEPC121 [0.313 MB]
WEPC123	Numerical Algorithm based on the PDE Method for the Solution of the Fokker-Planck Equation	2298
	M. Dolinska NASU/INR, Kiev, Ukraine C. Dimopoulou, A. Dolinskii, F. Nolden, M. Steck GSI, Darmstadt, Germany
	Funding: Work supported by HIC for FAIR This paper discus a fast and accurate algorithm for numerical solution of Fokker-Planck equation based on the solution of the parabolic Partial Differential Equations (PDE), where the Crank–Nicholson scheme is used. The stability, convergence and round-off errors of the algorithm are studied. The numerical results on Fokker–Planck equation solution with PDE method are compared with other numerical methods. Using the PDE solver, we will be able to predict the stochastic cooling process of notch filter in storage rings.
WEPC125	Higher Order Modes in Coupled Cavities of the FLASH Module ACC39	2301
	R.M. Jones, I.R.R. Shinton UMAN, Manchester, United Kingdom Z. Li SLAC, Menlo Park, California, USA
	We analyse the higher order modes (HOMs) in the 3.9GHz bunch shaping cavities installed in the FLASH facility at DESY. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations are used to investigate the modes in these cavities. This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39. Coupled inter-cavity modes are simulated together with a limited band of trapped modes.
WEPC128	Application of Dynamical Maps to the FFAG EMMA Commissioning*	2304
	Y. Giboudot, R. Nilavalan Brunel University, Middlesex, United Kingdom A. Wolski The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by the Engineering and Physical Sciences Research Council, UK. The lattice of the Non Scaling FFAG EMMA has four degrees of freedom (strengths and transverse positions of each of the two quadrupoles in each periodic cell). Dynamical maps computed from an analytical representation of the magnetic field may be used to predict the beam dynamics in any configuration of the lattice. An interpolation technique using a mixed variable generating function representation for the map provides an efficient way to generate the map for any required lattice configuration, while ensuring symplecticity of the map. The interpolation technique is used in an optimisation routine, to identify the lattice configuration most closely machine specified dynamical properties, including the variation of time of flight with beam energy (a key characteristic for acceleration in EMMA). yoel.giboudot@stfc.ac.uk
WEPC132	Simulations of Surface Effects and Electron Emission from Diamond-Amplifier Cathodes	2307
	D.A. Dimitrov, R. Busby, J.R. Cary, D.N. Smithe Tech-X, Boulder, Colorado, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA X. Chang, T. Rao, J. Smedley, Q. Wu BNL, Upton, Long Island, New York, USA E. Wang PKU/IHIP, Beijing, People's Republic of China
	Funding: The authors wish to acknowledge the support of the U.S. Department of Energy (DOE) under grants DE-SC0004431 (Tech-X Corp.), DE-AC02-98CH10886 (BNL), and DE-SC0005713 (Stony Brook University). Emission of electrons in diamond experiments based on the promising diamond-amplifier concept* was recently demonstrated**. Transmission mode experiments have shown the potential to realize over two orders of magnitude charge amplification. However, the recent emission experiments indicate that surface effects should be understood in detail to build cathodes with optimal properties. We have made progress in understanding secondary electron generation and charge transport in diamond with models we implemented in the VORPAL particle-in-cell computational framework. We will introduce models that we have been implementing for surface effects (band bending and electron affinity), charge trapping, and electron emission from diamond. Then, we will present results from 3D VORPAL diamond-vacuum simulations with the integrated capabilities on generating electrons and holes, initiated by energetic primary electrons, charge transport, and then emission of electrons from diamond into vacuum. Finally, we will discuss simulation results on the dependence of the electron emission on diamond surface properties. * I. Ben-Zvi et al., Secondary emission enhanced photoinjector, C-AD Accel. Phys. Rep. C-A/AP/149, BNL (2004). ** X. Chang et al., Phys. Rev. Lett. 105, 164801 (2010).
WEPC134	Unified Accelerator Modeling Using the Bmad Software Library	2310
	D. Sagan, I.V. Bazarov, J.Y. Chee, J.A. Crittenden, G. Dugan, K. Finkelstein, G.H. Hoffstaetter, C.E. Mayes, S. Milashuk, D. L. Rubin, J.P. Shanks CLASSE, Ithaca, New York, USA R. Cope CSU, Fort Collins, Colorado, USA
	Funding: Work supported by the National Science Foundation and by the US Department of Energy under contract numbers PHY-0734867 and DE-FC02-08ER41538. The Bmad software library has proved to be a useful tool for accelerator simulations owing to its modular, object-oriented design. It is now used in a number of design, simulation and control programs at the Cornell Laboratory for Accelerator-based Sciences and Education. Work is ongoing to expand Bmad in a number of directions. One aim is tohave a complete framework in order to simulate Cornell's Energy Recovery Linac from Gun cathode (including space-charge) to photon generation to photon tracking through to the x-ray experimental end stations. Other work includes synchrotron radiation tracking including reflections from the vacuum chamber walls which is useful for electron cloud investigations, spin tracking, beam break-up instability, intra-beam scattering, etc. This paper will discuss the current state of the Bmad software along with the long-term goals.
WEPC135	Recent Developments in Modeling Time-resolved Shielded-pickup Measurements of Electron Cloud Buildup at CESRTA	2313
	J.A. Crittenden, Y. Li, X. Liu, M.A. Palmer, J.P. Sikora CLASSE, Ithaca, New York, USA R.P. Badman Syracuse University, Syracuse, USA S. Calatroni, G. Rumolo CERN, Geneva, Switzerland S. Kato KEK, Ibaraki, Japan
	Funding: Work supported by the U.S. National Science Foundation PHY-0734867, PHY-1002467 and the U.S. Department of Energy DE-FC02-08ER41538 The Cornell Electron Storage Ring Test Accelerator program includes investigations into the mitigation of electron cloud buildup using a variety of techniques in custom vacuum chambers. The CESR ring accommodates two such chambers equipped with BPM-style pickup detectors shielded against the direct beam-induced signal. The signals provide time-resolved information on cloud development. Results for diamond-like carbon, amorphous carbon, and TiN coatings have been compared to those for an uncoated aluminum chamber. Here we report on extensions to the ECLOUD modeling code which refine its description of a variety of new types of in situ vacuum chamber comparisons. Our results highlight the sensitivity afforded by these measurements to the modeled photoelectron production and secondary yield parameters. We draw conclusions comparing the photoelectron and secondary yield properties of the various vacuum chamber coatings, including conditioning effects as a function of synchrotron radiation dose. We find substantial conditioning effects in both the quantum efficiency for producing photoelectrons and in the secondary yield.
WEPC137	Undulator Radiation Simulation by QUINDI	2316
	D. Schiller, E. Hemsing, J.B. Rosenzweig UCLA, Los Angeles, California, USA
	QUINDI, a code developed to simulate coherent emission from bending systems, has been upgraded to include undulators as a beamline element. This approach allows us to better model the radiation produced by a relativistic electron bunch propagating through such a device.
WEPC141	Application of the SYNRAD3D Photon-Tracking Model to Shielded Pickup Measurements of Electron Cloud Buildup at CesrTA	2319
	L.E. Boon Purdue University, West Lafayette, Indiana, USA J.A. Crittenden, T. Ishibashi CLASSE, Ithaca, New York, USA K.C. Harkay ANL, Argonne, USA
	Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. We present calculations of synchrotron radiation photon reflection in the vacuum chamber at the Cornell Electron Storage Ring Test Accelerator (CesrTA), applying them as input to the electron cloud buildup code ECLOUD to model time-resolved local measurements with shielded pickup detectors. The recently developed SYNRAD3D photon-tracking code employs a reflection model based on data from the Center for X-Ray Optics at LBNL. This study investigates the dependence of electron cloud buildup on the azimuthal position and kinetic energy distribution of photoelectron production on the vacuum chamber wall.
WEPC142	High Performance Web Applications for Particle Accelerator Control Systems	2322
	G. Mazzitelli, C. Bisegni, P. Ciuffetti, G. Di Pirro, A. Stecchi INFN/LNF, Frascati (Roma), Italy S. Calabrò, L.G. Foggetta IN2P3-CNRS, Orsay, France L. Catani, F. Zani INFN-Roma II, Roma, Italy
	The integration of web technologies and applications has been one of the major trends for the development of new services for control systems of particle accelerators and large experimental apparatuses. Nowadays, high performance web technologies exhibit some features that would allow their deeper integration in a control system and their employment in developing control system's core components. In this paper we discuss the results of preliminary investigations of a new paradigm for a particle accelerator control system and associated machine data acquisition system based on a synergic combination of network distributed cache memory and a non-relational key/value database. Storage speed, network memory data retrieve throughput and database queries execution, as well as scalability and redundancy of the systems, are presented and critically reviewed.
	Poster WEPC142 [8.902 MB]
WEPC143	First Operation of the SACLA Control System in SPring-8	2325
	R. Tanaka, Y. Furukawa, T. Hirono, M. Ishii, M. Kago, A. Kiyomichi, T. Masuda, T. Matsumoto, T. Matsushita, T. Ohata, C. Saji, T. Sugimoto, M. Yamaga, A. Yamashita JASRI/SPring-8, Hyogo-ken, Japan T. Fukui, T. Hatsui, N. Hosoda, T. Ohshima, T. Otake, Y. Otake, H. Takebe RIKEN/SPring-8, Hyogo, Japan H. Maesaka RIKEN Spring-8 Harima, Hyogo, Japan
	The control system design of the X-ray free electron laser facility (SACLA) in SPring-8 has started in 2006. Now, the facility has completed to start beam commissioning in February 2011. The electron beams were successfully accelerated up to 8 GeV and the first SASE X-ray was observed. The control system adopts the 3-tier standard model by using MADOCA framework developed in SPring-8. The upper control layer consists of Linux PCs for operator consoles, Sybase RDBMS for data logging and FC-based NAS for NFS. The lower layer consists of VMEbus systems with off-the-shelf I/O boards and specially developed boards for RF waveform processing with high precision. Solaris OS is adopted to operate VMEbus CPU. The PLC is used for slow control and connected to the VME systems via FL-net. The Device-net is adopted for frontend device control to reduce the number of signal cables. Some of VMEbus systems have a beam-synchronized data-taking system to meet 60Hz electron beam operation for the beam tuning diagnostics. The accelerator control system has gateways not only to monitor device status but also control the tuning points of the facility utility system, especially cooling water.
WEPC144	Beam Monitor Deformation by Tohoku Earthquake and its Recovery Project	2328
	A. Miura, K. Hasegawa, H. Oguri, N. Ouchi JAEA/J-PARC, Tokai-mura, Japan Z. Igarashi, M. Ikegami, T. Miyao KEK, Ibaraki, Japan
	On March 11, 2011, the biggest earthquake occurred at Tohoku and North Kanto area in Japan. This earthquake and related ones have attacked J-PARC accelerators and caused the big damage. As for the linac beam monitors, some commissioning tools which were installed in the linac had damage and the air leakage was observed. In the first step of the recovery work, we checked the damage and put the emergency treatment for vacuum of the cavities. All beam monitors were observed, the leak from the vacuum devices was tested and the conduction of the signal cables was measured to compare the previous performance. In the next step, we started to order the new devices which should be replaced and to obtain the calibration data. We found the leakage from the phase monitors. The earthquake caused the crack and deformation at the welded points between the metallic parts and ceramic parts. And a wire of the profile monitor was broken while the beam position monitors have no damage. We are continuing this recovery work ongoingly.
WEPC145	Progress in Developing a PLC Control System for the PKUNIFTY	2331
	J. Zhao, J.E. Chen, Z.Y. Guo, Y.R. Lu, S.X. Peng, Q.F. Zhou PKU/IHIP, Beijing, People's Republic of China
	A compact remote PLC control system has been developed for the PKUNIFTY (Peking University Neutron Imaging FaciliTY). That facility is based on a 2 MeV deuteron RFQ accelerator. The PLC control system has been successfully used for the injector including ECR ion source and LEBT, and it worked reliably last year. Now the control of RFQ cavity, HEBT and Be target has been completed and tested. The interlock system has been enhanced. A low level RF control system, including the auto frequency control (AFC) and auto gain control (AGC) circuits, has been designed for the RFQ’s RF power system. Those circuits will work as a lower controller of the PLC control system. The main running parameters can be controlled by setting any desired range of values on the HMI. Test results of hardware and software are presented.
WEPC146	Design and Implementation of Distributed Control System for PEFP 100-MeV Proton Accelerator*	2334
	Y.-G. Song, Y.-S. Cho, J.-H. Jang, H.-J. Kwon KAERI, Daejon, Republic of Korea
	Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government. The Proton Engineering Frontier Project (PEFP) has been developing the control system for 100-MeV proton accelerator. The PEFP control system should be designed to fit control conditions based on networked and distributed real-time system composed of several sub-systems such as machine control, diagnostic control, timing, and interlock. In order to implement the distributed control system, the Experimental Physics and Industrial Control System (EPICS) has been chosen as the middleware of PEFP control system. The EPICS software provides a distributed architecture that supports a wide range of solution such as independent programming tool, operator interface tool, database and web-based archiving tools. In this paper, we will present the details of the design and implementation issues of the PEFP control system.
WEPC152	Android Based Mobile Monitoring System for EPICS Networks: Vacuum System Application*	2337
	I. Badillo, I. Arredondo, M. Eguiraun, J. Feuchtwanger, G. Harper ESS-Bilbao, Zamudio, Spain J. Jugo University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
	Funding: The present work is supported by the Basque Government and Spanish Ministry of Science and Innovation. When cabling is not really needed for performance reasons, wireless monitoring is a good choice for large scientific facilities like particle accelerators, due to the quick implementation. There are several wireless flavors: ZigBee, WiFi etc. depending on requirements of specific application. In this work, a wireless monitoring system for EPICS based on an Android device is presented. The task is to monitor the vacuum control system of ISHN project at ESSBilbao, where control system variables are acquired over the network and published in a mobile device. This allows the operator to check process variables everywhere the signal spreads. In this approach, a Python based server is continuously getting EPICS variables via CA protocol and sending them through a WiFi network using ICE middleware, a toolkit oriented to develop distributed applications. Finally, the mobile device reads and shows the data to the operator. The security of the communication is ensured by a limited WiFi signal spread, following the same idea as in NFC for larger distances. With this approach, local monitoring and control applications are easily implemented, useful in starting up and maintenance stages.
WEPC153	ISHN Ion Source Control System Overview and Future Developments	2340
	M. Eguiraun, I. Arredondo, J. Feuchtwanger, G. Harper, M. del Campo ESS-Bilbao, Zamudio, Spain J. Jugo University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain S. Varnasseri ESS Bilbao, Derio, Spain
	Funding: The present work is supported by the Basque Government and Spanish Ministry of Science and Innovation. ISHN project consist on a Penning ion source which will deliver up to 65 mA of H− beam pulsed at 50 Hz with a diagnostics vessel for beam testing purposes. The present work summarizes the control system of this research facility, and presents its future developments. ISHN consist of several power supplies for plasma generation and beam extraction, including auxiliary equipment and several diagnostics elements. The control system implemented with LabVIEW is based on PXI systems from National Instruments, using two PXI chassis connected through a dedicated fiber optic link between HV platform and ground. Source operation is managed by a real time processor, while additional tasks are performed by means of an FPGA. In addition, the control system uses a MySQL database for data logging, by means of a LabVIEW application connected to such DB. The integration of EPICS into the control system by deploying a Channel Access Server is the ongoing work, several alternatives are being tested. Finally, a high resolution synchronization system has been designed, for generating timing for triggers of plasma generation and extraction as well as data acquisition for beam diagnostics.
WEPC154	EPICS HyperArchiver: initial tests at ESSBilbao	2343
	M. del Campo ESS-Bilbao, Zamudio, Spain M.G. Giacchini, L.G. Giovannini INFN/LNL, Legnaro (PD), Italy J. Jugo University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
	Funding: The present work is supported by the Basque Government and Spanish Ministry of Science and Innovation. The aim of this work is to present the results obtained after different tests performed regarding data storage for an Ion Source, by means of an EPICS control system at ESS-Bilbao (Spain). As a first approach, data was recorded on a MySQL database, using a traditional EPICS RDB Channel Archiver instance, maintained at ORNL SNS (USA). Nevertheless, initial results shown the need of an evolution towards a high performance scalable database. Therefore, current tests are focused on the customization and usage of a HyperArchiver instance, developed at INFN/LNL (Italy), which uses Hypertable as its main database. Hypertable is a distributed, high performance non relational database, released under GNU licence and focused on data-intensive tasks. At ESS Bilbao, a slightly modified version of the HyperArchiver was used, due to the necessity of an improvement on the management of array PVs. Regarding data retrieval and visualization, a python GUI developed at ESS-Bilbao was used, in opposition to the traditional CSS data browser, trying to make data retrieval as fast and simple as possible. Hypertable is presented as a high performance alternative to MySQL for any EPICS control system.
WEPC155	Fast Acquisition Multipurpose Controller with EPICS Integration and Data Logging	2346
	I. Arredondo, D. Belver, P. Echevarria, H. Hassanzadegan, M. del Campo ESS-Bilbao, Zamudio, Spain V. Etxebarria, J. Jugo University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain N. Garmendia, L. Muguira ESS Bilbao, Bilbao, Spain
	Funding: Funding Agency The present work is supported by the Basque Government and Spanish Ministry of Science and Innovation. This work introduces a fast acquisition multipurpose controller (MC), based on a XML configuration with EPICS integration and Data Logging. The main hardware is an FPGA based board, connected to a Host PC. This Host computer acts as the local controller and implements an IOC, integrating the device into an EPICS network. Java has been used as the main programming language in order to make the device fit the desired application. The whole process includes the use of different technologies: JNA to handle FPGA API, JavaIOC to integrate EPICS and XML w3c DOM classes to configure each particular application. Furthermore, a MySQL database is used for data storage, together with the deployment of an EPICS ArchiveEngine instance, offering the possibility to record data from both, the ArchiveEngine and a specifically designed Java library. The developed Java specific tools include different methods: FPGA management, creation and use of EPICS server, mathematical data processing, Archive Engine's MySQL database connection and creation/initialization of the application structure by means of an XML file. This MC has been used to implement a BPM and an LLRF applications for ESS-Bilbao.
WEPC156	Virtual Power Supply Control Environment for the TPS Project	2349
	Y.-S. Cheng, Y.-T. Chang, J. Chen, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo, C.-Y. Liao, C.Y. Wu NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS) is the latest generation of 3 GeV synchrotron light source which has been under construction since 2010. The control system infrastructure of TPS project is based upon the EPICS framework. In order to develop the control applications before power supplies of magnets delivered, it is necessary to set up the virtual control environment to develop high level application programs for the power supplies of magnets in advance. The high level application programs include operation process, degauss process and etc. for power supplies of magnet. The soft-IOCs (Input Output Controller) and various database records are needed to be built to simulate the power supply control environment. In addition, the operation interfaces of power supply will be designed and integrated according to location properties. The efforts will be described at this report.
WEPC157	Post-mortem Analysis at TLS	2352
	Y.R. Pan, Y.-T. Chang, J. Chen, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo, C.-Y. Liao NSRRC, Hsinchu, Taiwan
	High availability and stability of the beam are important issues for the synchrotron light source. Analyzing of the post-mortem data is one of the most important approaches to reflect the machine error and identify the reason of beam trip. The post-mortem system has been developed at Taiwan Light Source (TLS) in 2008. This diagnostic data can provide useful information for troubleshooting and improve the beam reliability. The various diagnostic signals are read from hardware buffer and written to the file system by the post-mortem event trigger, which is generated by the signals of the beam trip detector, the superconducting RF system interlock and the superconducting insertion device interlock. In this report a processing is running to check whether a new trip event, promptly find out the unusual signals, and generate an analyzing result message. The detail will be discussed and summarized.
WEPC158	The EMMA Accelerator, A Diagnostic Systems Overview	2355
	R.J. Smith, M. Dufau, C. Hill, J.K. Jones, A. Kalinin, L. Ma, P.A. McIntosh, B.D. Muratori, B.J.A. Shepherd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J.S. Berg BNL, Upton, Long Island, New York, USA N. Bliss, G. Cox, A. Gallagher, A. Oates STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom R.G. Borrell WareWorks Ltd, Manchester, United Kingdom J.L. Crisp FRIB, East Lansing, Michigan, USA K.M. Hock, D.J. Holder Cockcroft Institute, Warrington, Cheshire, United Kingdom M.G. Ibison, I. Kirkman The University of Liverpool, Liverpool, United Kingdom D.J. Kelliher, S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	The ‘EMMA’ Non-Scaling Fixed Field Alternating Gradient (NS-FFAG) international project is currently being commissioned at Daresbury Laboratory, UK. This accelerator has been equipped with a number of diagnostic systems to facilitate this. These systems include a novel time-domain-multiplexing BPM system, moveable screen systems, a time-of-flight instrument, Faraday cups, and injection/extraction tomography sections to analyse the single bunch beams. An upgrade still to implement includes the installation of a fast wall current monitor. This paper gives an overview of these systems and shows some data and results that have contributed to the successful demonstration of a serpentine acceleration by this novel accelerator.
WEPC159	A Python Tracking Code and GUI for Control Room Operations	2358
	M.T. Heron, J. Rowland Diamond, Oxfordshire, United Kingdom
	Considerable use has been made in recent years of accelerator physics modelling and online tools under Matlab. These have demonstrated the benefits of operating in a rich integrated environment and further given good portability across projects and operating systems. As a possible alternative to Matlab, Diamond has been evaluating options based on Python. Python together with the Numpy libraries and Qt Graphics provides an environment which offers a lot of the functionality of Matlab. This paper presents these developments, which include a tracking code, symplectic integrator, twiss and response matrix together with a GUI interface.
WEPC162	Investigations into Non-linear Beam Dynamics in Electrostatic Storage Rings	2361
	D. Newton, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom O.E. Gorda MPI-K, Heidelberg, Germany D. Newton The University of Liverpool, Liverpool, United Kingdom A.I. Papash JINR, Dubna, Moscow Region, Russia
	Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG-328. Electrostatic (ES) storage rings provide a cost-effective solution to the problem of confining low energy (beta << 1) charged particles and ions, whilst controlling the beam properties, for use in multi-pass experiments. However, compared to magnetic storage rings, the beam dynamics calculations for an ES ring show subtle differences, especially in the coupling of the longitudinal and transverse velocities and in the focusing properties of bending element fringe fields. Using the nominal design for a prototype ES ring, realistic trajectories (including fringe fields and non-linear field components) have been calculated and a comparison is made with linear lattice simulations. The effect of the non-linear field components on the beam parameters is discussed.
WEPC163	A New Embedded Radiation Monitor System for Dosimetry at the European XFEL	2364
	F. Schmidt-Föhre, D. Nölle, R. Susen, K. Wittenburg DESY, Hamburg, Germany L. Fröhlich ELETTRA, Basovizza, Italy
	The upcoming European XFEL will be built at a length of approx. 3.4 km between the campus of the Deutsches Elektronen-Synchrotron DESY at Hamburg and Schenefeld at Schleswig-Holstein for commissioning in 2015. The XFEL utilizes various electronic systems for machine control, diagnostics and safety. To achieve a cheap and compact accelerator construction, the beam pipe and its nearby electronic supply systems are located inside the same tunnel, charged by an evident amount of radiation in certain sections of the XFEL. To insure the lifecycle and function of electronics and magnetic structures like undulators in these XFEL radiation fields, all electronic systems located inside the tunnel will be sufficiently shielded according to pre-estimated radiation levels. In addition, these electronics and the undulator parts will be monitored for the impact of Gamma- and Neutron-radiation by a new versatile and compact radiation monitor system. It measures the accumulated dose in the electronic cabinets along the XFEL to ensure an exchange of radiated parts before significant radiation damage occurs. First prototype measurements at different radiation sources will be presented.
WEPC164	First Operation of a Fiber Beam Loss Monitor at the SACLA FEL	2367
	X.-M. Maréchal, T. Itoga JASRI/SPring-8, Sayo-gun, Japan Y. Asano RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	A fiber-based Cerenkov beam loss monitor (CBLM) has been developed as a quick and long-range detection tool for radiation safety at the X-ray FEL SACLA (SPring-8 angstrom compact free electron laser) to minimize electron beam losses. Based on tests carried out at the 250 MeV SPring-8 Compact SASE Source facility, large core (400 μm), long (>120 m) multimode fibers were selected and installed in the undulator section of SACLA. We report on the first few months of operation of the CBLM. During the commissioning of the X-FEL, the CBLM has performed effectively, with a detection limit below 10 pC per pulse across the 110 meters of the in-vacuum undulators, and with a position accuracy of less than 2 m. Experimental results are presented along with detailed numerical studies including the geometry of in-vacuum insertion devices, and discussed.
WEPC165	Monte Carlo Simulation of the Total Dose Distribution around the 12 MeV UPC Race-track Microtron and Radiation Shielding Calculations	2370
	C. de la Fuente, M.A. Duch, Yu.A. Kubyshin UPC, Barcelona, Spain V.I. Shvedunov MSU, Moscow, Russia
	The Technical University of Catalonia is building a miniature 12 MeV electron race-track microtron for medical applications. In the paper we study the leakage radiation caused by beam losses inside the accelerator head, as well as the bremstrahlung radiation produced by the primary beam in the commissioning setting. Results of Monte Carlo simulations using the PENELOPE code are presented and two shielding schemes, global and local, are studied. The obtained shielding parameters are compared with estimates based on international recommendations of the radiation safety standards.
WEPC166	Licensing and Safety Issues of the ESS Accelerator	2373
	P.E.T. Jacobsson, M. Brandin, D. Ene, T. Hansson ESS, Lund, Sweden
	The licensing process for the European Spallation Source (ESS) has started up. The process includes both an application to the Environmental Court in Sweden as well as the application towards the Swedish Radiation Protection Authority (SSM). The applications will be based on an Environmental Impact Assessment EIA) and a Safety Analysis Report (SAR). One important step has been to define which regulations that apply for ESS. ESS has also set up General Safety Objectives (GSO). Based on the GSO and the legal requirements, the process design of the whole ESS facility is ongoing. This paper will focus upon the radiation safety issues related to the accelerator. This includes items as radiation shielding, personal protection system and operation emissions. Analyses and calculations, based on a preliminary design and layout of the ESS accelerator, will be presented. Discussion is made on issues like shielding material, shielding design and analysis models.
WEPC168	Implementation of a Workflow Model to Store and Analyze Measured Data at the ESS-Bilbao Ion Source Test Stand	2376
	Z. Izaola, M. Eguiraun, M. del Campo ESS-Bilbao, Zamudio, Spain I. Bustinduy ESS Bilbao, Bilbao, Spain
	Funding: The present work is supported by the Basque Government and Spanish Ministry of Science and Innovation. In order to fully characterize the experimentally measured beam in any accelerator facility, both diagnostics measurements and operating parameters need to be stored and correlated. Generating thus, a substantial amount of data. To address this problem in the ESS-Bilbao Ion Source Test Stand (ITUR), we have developed a software toolkit. This software stores Pepperpot, Faraday-Cup, Retarding Potential Analyzer, ACCT and DCCT measurements in a relational database associated with the operating parameter values at the time of measurement. Furthermore, the toolkit stores in the same database the beam transverse dynamics parameters processed from the pepperpot device. This allows to connect easily the beam physics with the accelerator running parameters. MySQL has been used as database backend and Matlab as programming language.
WEPC169	BPM System Interlock for Machine Protection at SOLEIL	2379
	J.-C. Denard, C. Herbeaux, M. Labat, V. Leroux, A. Loulergue, J.L. Marlats SOLEIL, Gif-sur-Yvette, France
	SOLEIL, a third generation light source, has its Beam Position Monitors (BPM) processed by the LIBERA electronics built by Instrumentation Technologies. This electronics initiated and specified by SOLEIL features a fast hardware interlock output for machine protection. Although interlocks are available in both horizontal and vertical planes, it was initially thought that only the vertical interlocks would be useful. Actually, the high photon beam power densities (up to 1kW/mm2) generated by the in-vacuum undulators could damage vacuum chamber elements in case of corrector power supply failures in horizontal or vertical plane. Crotch absorbers, XBPMs and their upstream absorbers were designed on the basis that they will be protected with interlock thresholds not tighter than ±1mm. This approach was also applied for specifying the apertures of the XBPMs and of their upstream absorbers. More recently tracking simulation has shown that the crotch absorber apertures downstream the new canted undulators needed special attention.
WEPC170	Handling of BLM Abort Thresholds in the LHC	2382
	E. Nebot Del Busto, B. Dehning, E.B. Holzer, S. Jackson, G. Kruk, M. Nemcic, A. Nordt, A. Orecka, C. Roderick, M. Sapinski, A. Skaugen, C. Zamantzas CERN, Geneva, Switzerland
	The Beam Loss Monitoring system (BLM) for the LHC consists of about 3600 Ionization Chambers located around the ring. Its main purpose is to request a beam abort when the measured losses exceed a certain threshold. The BLM detectors integrate the measured signals in 12 different time intervals (running from 40 us to 83.8 s) enabling for a different set of abort thresholds depending on the duration of the beam loss. Furthermore, 32 energy levels running from 0 to 7 TeV account for the fact that the energy density of a particle shower increases with the energy of the primary particle, i.e. the beam energy. Thus, about 1.3·106 thresholds must be handled and send to the appropriate processing modules for the system to function. These thresholds are highly critical for the safety of the machine and depend to a large part on human judgment, which cannot be replaced by automatic test procedures. The BLM team has defined well established procedures to compute, set and check new BLM thresholds, in order to avoid and/or find non-conformities due to manipulation. These procedures, as well as the tools developed to automate this process are described in detail in this document.
WEPC171	Requirements of a Beam Loss Monitoring System for the CLIC Two Beam Modules	2385
	S. Mallows The University of Liverpool, Liverpool, United Kingdom E.B. Holzer, A.P. Mechev, J.W. van Hoorne CERN, Geneva, Switzerland C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	he Compact Linear Collider (CLIC) study investigates the feasibility of a high-energy electron-positron linear collider optimized for a centre of mass energy of 3 TeV. To achieve the high accelerating gradients, the RF power is produced by a novel two-beam acceleration method in which a decelerating drive beam supplies energy to the main accelerating beam. The linacs are arranged in modular structures referred to as the two beam modules which cover 42 km of beamline. Beam losses from either beam can have severe consequences due to the high intensity drive beam and the high energy, small emittance main beam. This paper presents recent developments towards the design of a Cherenkov fiber BLM system and discusses its ability to distinguish losses originating from either beam.
WEPC172	Beam-induced Quench Test of a LHC Main Quadrupole	2388
	A. Priebe, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, E.B. Holzer, C. Kurfuerst, E. Nebot Del Busto, A. Nordt, M. Sapinski, J. Steckert, A.P. Verweij, C. Zamantzas CERN, Geneva, Switzerland A. Priebe EPFL, Lausanne, Switzerland
	Unexpected beam loss might lead to transition of a superconducting accelerator magnet to a normal conducting state. The LHC beam loss monitoring (BLM) system is designed to abort the beam before the energy deposited in the magnet coils reaches a quench-provoking level. In order to verify the threshold settings generated by simulation, a series of beam-induced quench tests at various beam energies have been performed. The beam losses are generated by means of an orbit bump peaked in one of the main quadrupole magnets. The analysis not only includes BLM data but also data from the electrical quench protection and cryogenic systems. The measurements are compared to Geant4 simulations of energy deposition inside the coils and corresponding BLM signal outside the cryostat. The results are also extrapolated to higher beam energies.
WEPC173	LHC Magnet Quench Test with Beam Loss Generated by Wire Scan	2391
	M. Sapinski, F. Cerutti, K. Dahlerup-Petersen, B. Dehning, J. Emery, A. Ferrari, A. Guerrero, E.B. Holzer, M. Koujili, A. Lechner, E. Nebot Del Busto, M. Scheubel, J. Steckert, A.P. Verweij, J. Wenninger CERN, Geneva, Switzerland
	Beam losses with millisecond duration have been observed in the LHC in 2010 and 2011. They are expected to be provoked by dust particles falling into the beam. These losses could compromise the LHC availability if they provoke quenches of superconducting magnets. In order to investigate the quench limits for this loss mechanism, a quench test using the wire scanner has been performed, with the wire movement through the beam mimicking a loss with similar spatial and temporal distribution as in the case of dust particles. This paper will show the conclusions reached for millisecond-duration dust-provoked quench limits. It will include details on the maximum energy deposited in the coil as estimated using FLUKA code, showing good agreement with quench limit estimated from the heat transfer code QP3. In addition, information on the damage limit for carbon wires in proton beams will be presented, following electron microscope analysis which revealed strong wire sublimation.
WEPC174	A Failure Catalogue for the LHC	2394
	S. Wagner, R. Schmidt, B. Todd, J.A. Uythoven, M. Zerlauth CERN, Geneva, Switzerland
	The LHC, with a stored energy of more than 360 MJ per beam, requires a complex machine protection system to prevent equipment damage. The system was designed based on a large number of possible failures in the subsystems and operational phases of the LHC. This led to a mixed system with active and passive protection. The active part monitors many thousand parameters (such as beam losses, temperatures in superconducting magnets, power converter currents, etc.) and triggers a beam dump in case a failure is detected. The passive part includes protection elements like collimators and beam absorbers to ensure the prevention of damage in case of single turn beam losses (e.g. during beam transfer and injection). So far, the knowledge of the possible failures is distributed over the different teams involved in the design, construction and operation of the LHC. A newly started project aims at bringing together this knowledge in a common failure catalogue. The chosen approach in addition is expected to allow for the identification of failures that might not have been considered yet or that require further measures. This paper introduces the approach and presents the first experience.
WEPC175	FLUKA Studies of the Asynchronous Beam Dump Effects on LHC Point 6	2397
	R. Versaci, V. Boccone, B. Goddard, A. Mereghetti, R. Schmidt, V. Vlachoudis CERN, Geneva, Switzerland
	The LHC is a record-breaking machine for beam energy and intensity. An intense effort has therefore been deployed in simulating critical operational scenarios of energy deposition. FLUKA is the most widely used code for this kind of simulations at CERN because of the high reliability of its results and the ease to custom detailed simulations all along hundreds of meters of beam line. We have investigated the effects of an asynchronous beam dump on the LHC Point 6 where, beams with a stored energy of 360 MJ, can instantaneously release up to a few J cm-3 in the cryogenic magnets which have a quench limit of the order of the mJ cm-3. In the present paper we will briefly introduce FLUKA, describe the simulation approach, and discuss the evaluated maximum energy release onto the superconducting magnets during an asynchronous beam dump. We will then analyse the shielding provided by collimators installed in the area and discuss safety limits for the operation of the LHC.
WEPC176	Beam Loss Monitoring and Machine Protection System Design and Application for the ALICE Test Accelerator at Daresbury Laboratory	2400
	S.R. Buckley, J.-L. Fernández-Hernando STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	ALICE is a demonstrator accelerator system which has been designed and built at Daresbury Laboratory. The heart of this facility is an ERL accelerator and a powerful multi-terrawatt laser. It serves as an advanced test facility for novel accelerator and photon science applications. Beam loss monitoring and machine protection systems are vital areas for the successful operation of ALICE. These systems are required, both for efficient machine set up and for hardware protection during operation. This paper gives an overview of the system design, commissioning details and a summary of the systems’ effectiveness as a diagnostic tool.
WEPC177	Collimation of High Intensity Ion Beams*	2403
	J. Pfister, O. Meusel IAP, Frankfurt am Main, Germany O.K. Kester GSI, Darmstadt, Germany
	Funding: HIC for FAIR Intense ion beams with small phase space occupation (high brilliance) are mandatory to keep beam losses low in high current injector accelerators like those planned for FAIR. The low energy beam transport from the ion source towards the linac has to keep the emittance growth low and has to support the optimization of the ion source tune. The Frankfurt Neutron Source Facility FRANZ is currently under construction. An intense beam of protons (2 MeV, 200 mA) will be used for neutron production using the Li7(p,n)Be7 reaction for studies of the astrophysical s-process. A collimation channel, which can be adjusted to allow the transport of beams with a certain beam emittance, is an ideal tool to optimize the ion source tune in terms of beam brightness. Therefore a collimation channel in the Low Energy Beam Transport section will be used. Through defined apertures and transversal phase space rotation using focusing solenoids the beam halo as well as unwanted H2+ and H3+ fractions will be cut. Theoretical studies which were carried out so far and a first design of the setup will be presented.