resonance

Paper	Title	Other Keywords	Page
MOPLT023	Electron Model of an FFAG Muon Accelerator	acceleration, lattice, electron, simulation	587
	E. Keil CERN, Geneva J.S. Berg BNL, Upton, Long Island, New York A. Sessler LBNL, Berkeley, California
	Parameters are derived for the lattice and RF system of electron models of a non-scaling FFAG ring for accelerating muons. The models accelerate electrons from about 10 to about 20 MeV, and have circumferences between 10 and 17 m. Magnet types and dimensions, spacings, half apertures, about 12~mm by 20~mm,and number of cells are presented. The magnetic components are compared to existing magnets. The tune variation with momentum covers several integers, similar to that in a full machine, and allows the study of resonance crossing. The consequences of misaligned magnets are studied by simulation. The lattices are designed such that transition is at about 15 MeV. The variation of orbit length with momentum is less than 36~mm, and allows the study of acceleration outside a bucket. A 100~mm straight section, in each of the cells, is adequately long for an RF cavity operating at 3 GHz. Hamiltonian dynamics in longitudinal phase space close to transition is used to calculate the accelerating voltage needed. Acceleration is studied by simulation. Practical RF system design issues, e.g. RF power, and beam loading are estimated.
MOPLT028	In-Situ Vibration Measurements of the CTF2 Quadrupoles	quadrupole, alignment, linac, lattice	602
	S. Redaelli, W. Coosemans CERN, Geneva
	The Compact LInear Collider (CLIC), presently under study at the European Organization for Nuclear Research (CERN), aims at colliding high-energy ‘‘nanobeams'' at a luminosity of 10$35$\,cm-2s-1. Vibrations of the lattice elements, if not properly corrected, can result in a loss in performance by creating both unacceptable emittance growth in the linear accelerator and relative beam-beam offsets at the interaction point. Of particular concern are the vibrations induced by the accelerator environment. For example, the circulating water used to cool the lattice quadrupoles will increase magnet vibration levels. In the framework of the CLIC stability study, in-situ measurements of quadrupole vibrations have been performed at the CLIC Test Facility 2 (CTF2) with all accelerator equipment switched on. Since the CTF2 quadrupoles and their alignment support structures are realistic prototypes of those to be used in the CLIC linac, the measurements provide a realistic estimate of the CLIC magnet vibrations in a realistic accelerator working environment.
MOPLT046	Overcoming Performance Limitations due to Synchrobetatron Resonances in the HERA Electron Ring	optics, closed-orbit, betatron, sextupole	650
	F.J. Willeke DESY, Hamburg
	The HERA Electron Ring was suffering from strong synchrobetatron resonances which have been particularly detrimental after the HERA luminosity upgrade because of a reduced sychrotron tune due to stronger transverse focusing and a shift in the damping distribution in favor of transverse damping. It turned out to be most difficult to store a beam at the preferred working point for high electron spin polarization between the 2nd and the 3rd synchro-betatron satellite of the horizontal integer resonance. A comparative study of the resonance strength did not reveal any significant additional disadvantage of the new beam optics. However, a mechanism driven by closed orbit distortions was discovered which can increase the width of the resonance Qx+2Qs=0 by a large factor. This explains the operational difficulties. The remedy against this effect is quite straight forward. The Fourier component of the closed orbit near the horizontal tune must be avoided. This is enforced in HERA operations by rigerous orbit corrections and an orbit feedback system which reproduces well-corrected orbits reliably. Synchrobetatron resonances do not constitute a performance limitation of polarized lepton proton collisions in HERA any more.
MOPLT087	Research of Possibility to use Beam Polarization for Absolute Energy Calibration in High-precision Measurement of Tau Lepton Mass at VEPP-4M	polarization, betatron, energy-calibration, synchrotron	737
	A.V. Bogomyagkov, V. Kiselev, E.V. Kremyanskaya, E. Levichev, S.A. Nikitin, I.B. Nikolaev, E.A. Simonov, A.N. Skrinsky BINP SB RAS, Novosibirsk
	Experiments of 2002-2003 years on measurement of duration of beam polarization existence in VEPP-4M electron-positron storage ring after injection of polarized beams from VEPP-3 booster at energies in the vicinity of tau-lepton production threshold (1777 MeV) are described. Polarized beams in such conditions are planned to use in the experiment at VEPP-4M with KEDR detector on high precision measurement of tau-lepton mass wiyh the help of resonant depolarization technique for absolute calibration of particle energy. It was shown that despite of closeness of the strong depolarizing integer spin resonance (1763 MeV) the polarization lifetime though is limited, but still is sufficient for realization of energy calibration procedure with a high accuracy (10-6).
MOPLT159	RF Techniques for Improved Luminosity at RHIC	emittance, booster, luminosity, damping	905
	J.M. Brennan, M. Blaskiewicz, J. Butler, J. DeLong, W. Fischer, T. Hayes BNL, Upton, Long Island, New York
	The Relativistic Heavy Ion Collider has improved its luminosity performance significantly in the course of the first three physics runs. A number of special techniques for the operation of the rf systems have been developed to facilitate these improvements. Herein we describe these techniques, which include: an ultra low-noise rf source for the 197 MHz storage cavities; synchronization of the two rings during acceleration (including crossing the transition energy) to avoid spurious collisions on the ramp, which modulate the beam-beam tune shift; a frequency shift switch-on technique for transferring bunches from the acceleration to the storage rf systems; installation of dedicated 200 MHz cavities to provide longitudinal Landau damping on the ramp, and automated corrections to longitudinal injection parameters to minimize emittance growth.
MOPLT167	RHIC Operation with Longitudinally Polarized Protons	polarization, proton, injection, synchrotron	920
	H. Huang, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Drees, W. Fischer, A.U. Luccio, W.W. MacKay, C. Montag, F.C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, S. Tepikian, D. Trbojevic, J. Van Zeijts, A.Y. Zelinsky, S.Y. Zhang BNL, Upton, Long Island, New York
	Longitudinally polarized proton beams have been accelerated, stored and collided at 100GeV in the Relativistic Heavy Ion Collider (RHIC) to study spin effects in the hadronic reactions. The essential equipment includes four Siberian snakes, eight spin rotators and a fast relative polarimeters in each of the two RHIC rings as well as local polarimeters at the STAR and PHENIX detectors. This paper summarizes the performance of RHIC as a polarized proton collider.
MOPLT172	Quest for a New Working Point in RHIC	proton, injection, ion, simulation	929
	R. Tomas, M. Bai, W. Fischer, V. Ptitsyn, T. Roser, T. Satogata BNL, Upton, Long Island, New York
	The beam-beam interaction is a limiting factor in RHIC's performance, particularly in proton operation. Changing the working point is a strategy to minimize the beam-beam effect and improve the performance of the machine. Experiments at injection energy and simulations have been performed for a set of working points in order to determine what are the best candidates.
TUXLH02	HERA Performance Upgrade: Achievements and Plans for the Future	proton, lepton, luminosity, interaction-region	93
	M.G. Minty DESY, Hamburg
	Having surpassed the design luminosity of 1.5 x 1031/cm2s already in 1997, an ambitious upgrade of the HERA proton-lepton collider was undertaken in 2000/2001 to provide both higher luminosity and longitudinally polarized lepton beams in the colliding beam experiments, H1 and ZEUS, and for the internal gas target experiment, HERMES. Routine operation following the upgrade has commenced. Initially experimental backgrounds limited the total beam currents so the number of colliding bunches was reduced while maintaining high single-bunch beam currents. With nominal, pre-upgrade, bunch currents the measured specific luminosity is 2.5 times higher than before, however about 15% smaller than design. Following modifications to alleviate the high backgrounds in 2003, HERA is now again operating with the design number of bunches and the total beam currents are being steadily increased. With only 40% of the total design current, peak luminosities of 2.5 x 1031/cm2s have been demonstrated with a longitudinal polarization of >40%. In this presentation the experiences from the upgrade commissioning will be reviewed. Plans for improvement and pronections for the future will be described.
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TUPKF016	Dynamic Lorentz Force Detuning Studies in TESLA Cavities	linac, coupling, beam-loading, acceleration	994
	V. Ayvazyan, S. Simrock DESY, Hamburg
	Dynamic detuning of the superconducting rf cavities due to Lorentz force induced mechanical excitation is a critical concern since the magnitude can approach the cavity bandwidth and require significant additional rf power for field control. In this paper, the influence of high accelerating fields on the resonance frequency in superconducting TESLA cavities is discussed. Cavities at the TESLA Test Facility have been operated at the design operating gradient close to 25 MV/m. It is shown that Lorentz force detuning constant factors are different for different cavities, significant spread have been observed.
TUPLT002	The Small-gap Undulator Impedance Study	impedance, vacuum, undulator, synchrotron	1132
	M. Ivanyan, V.M. Tsakanov CANDLE, Yerevan
	The small gap undulator vacuum chamber resistive impedance model is developed. The vacuum chamber is considered as equal-radii tubes with the different wall materials (stainless steel "copper" stainless steel). The complete impedance was calculated as a sum of tubes and transitions impedances. The modal expansion method for transition impedance calculation is presented.
TUPLT008	A Retrofit Technique for Kicker Beam-coupling Impedance Reduction	kicker, impedance, simulation, extraction	1144
	F. Caspers, E.H.R. Gaxiola, T. Kroyer, M. Timmins, J.A. Uythoven CERN, Geneva S.S. Kurennoy LANL/LANSCE, Los Alamos, New Mexico
	The reduction of the impedance of operational ferrite kicker structures may be desirable in order to avoid rebuilding such a device. Often resistively coated ceramic plates or tubes are installed for this purpose but at the expense of available aperture. Ceramic U-shaped profiles with a resistive coating fitting between the ellipse of the beam and the rectangular kicker aperture have been used to significantly reduce the impedance of the magnet, while having a limited effect on the available physical aperture Details of this method, constraints, measurements and simulation results as well as practical aspects are presented and discussed.
TUPLT047	First Results of Pulsed Superconducting Half-wave Resonators	linac, vacuum, synchrotron, coupling	1258
	R. Stassen, R. Eichhorn, F.M. Esser, B. Laatsch, R. Maier, G. Schug, R. Tölle FZJ/IKP, Jülich
	A pulsed linac for the cooler synchrotron COSY was projected based on superconductive half-wave resonators (HWRs). The concept of single phased resonators is a great challenge related to the requirement of accelerating protons and deuterons up to a similar energy. A cryomodule, which houses four cavities was designed in Cooperation with FZJ-ZAT, taking into account the restricted space and the special requirements of a linear accelerator. Two prototypes of the 160MHz Half-Wave Resonators (HWRs) were built at different companies. The fabrication differs slightly concerning the top and bottom parts of the cavity as well as the welding of the inner and outer conductor. First results of warm and cold measurements will be presented. The behaviour of the adjustable 4kW main coupler as well as the mechanical tuner can be tested together with the HWR in a new vertical test-cryostat.
TUPLT049	Triple-spoke Cavities in FZJ	simulation, vacuum, coupling, proton	1261
	E. Zaplatin, W. Braeutigam, R. Maier, M. Pap, M. Skrobucha, R. Stassen, R. Tölle FZJ/IKP, Jülich
	We report the situation with superconducting triple-spoke cavity activities at the research center FZJ in Juelich. The Nb prototype of the 700 MHz, beta=0.2 cavity is already in fabrication and should be tested this year. This work has been initiated for the European Spallation Source project. In the frames of the new European project of High Intensity Pulsed Proton Injector the 352 MHz, beta=0.48 cavity is under developments. This cavity should be designed, built and tested in the Lab within next few years.
TUPLT054	Design of the Low-beta, Quarter-wave Resonator and its Cryomodule for the SPIRAL 2 Project	alignment, vacuum, coupling, simulation	1276
	P.-E. Bernaudin, P. Bosland, S. Chel, G. Devanz, P. Hardy, F. Michel, P. de Girolamo CEA/DSM/DAPNIA, Gif-sur-Yvette
	The SPIRAL 2 project, to be built in GANIL, consists of a 40 MeV linear accelerator for 5 mA of deuterons and a target-source complex for the production of exotic isotopes. The accelerator is also optimised to accelerate q/A = 1/3 ion up to 14.4 MeV/u. The three stages of the linac are a RFQ (up to 0.75 MeV/A), a low beta (0.007) and a high beta (0.12) sections consisting of quarter-wave, 88 MHz superconducting resonators. This paper focuses on the low beta cavity and its cryomodule. The cavity nominal accelerating gradient is at least 6.5 MV/m in operation conditions. RF properties of the cavities are dealt with, as well as the mechanical ones: helium pressure effects, tunability, vibrations. The cryomodule is designed so as to save longitudinal space and therefore is partly assembled in clean room.
TUPLT058	High Intensity Linac Driver for the SPIRAL-2 Project : Design of Superconducting 88 MHz Quarter Wave Resonators (beta 0.12), Power Couplers and Cryomodules	linac, ion, heavy-ion, quadrupole	1285
	T. Junquera, J.-L. Biarrotte, S. Blivet, S. Bousson, C. Commeaux, G. Olry, H. Saugnac IPN, Orsay P. Balleyguier CEA/DAM, Bruyères-le-Châtel M. Fruneau, Y. Gomez-Martinez, E. Vernay, F. Vezzu LPSC, Grenoble
	A Superconducting Linac Driver, delivering deuterons with energy up to 40 MeV (5 mA) and heavy ions with energy of 14.5 MeV/u (1 mA ), is proposed for the Spiral-2 radioactive beams facility. For the high energy section of the linac, a superconducting 88 MHz Quarter Wave Resonator (beta 0.12) has been designed and the optimisation of RF and mechanical performances will be presented. Based on the present state-of-art of the Superconducting RF technology, maximum electric surface field of 40 MV/m and magnetic surface field of 80 mT, have been adopted which should allow to reach an accelerating field of 7 MV/m (energy gain 3 MeV per resonator). A first complete prototype is under construction. The high intensity deuteron beam specifications have imposed the design of an original power coupler (maximum power 20 KW). The RF, mechanical, and thermal characteristics will be presented. The design of the cryomodule for this high energy section, integrating two QWR with its associated equipments (couplers, tuners, helium tanks), will be presented.
TUPLT073	Observation of Coupling Resonance in HIMAC Synchrotron	coupling, electron, ion, synchrotron	1321
	T. Uesugi, T. Fujisawa, K. Noda, S. Shibuya, D. Tann, H. Uchiyama NIRS, Chiba-shi Y. Hashimoto KEK, Ibaraki I.N. Meshkov, E. Syresin JINR, Dubna, Moscow Region
	Coupling resonance was observed at operating points near to Qx-Qy=1. Two-dimensional profile of a beam at its equilibrium was measured, and it was found that the beam was inclined in transverse when the operating point is near to the resonance condition. We will present the detail of the measurement and the results.
TUPLT078	Study of Impedances and Instabilities in J-PARC	kicker, impedance, vacuum, synchrotron	1336
	T. Toyama, K. Ohmi KEK, Ibaraki Y. Shobuda JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
	J-PARC consists of two high intensity proton rings with energies of 3 GeV and 50 GeV. Longitudinal impedances and instabilities, which are caused by beam chamber, cavities, kicker magnets and others, are mainly discussed in this paper.
TUPLT088	Beam Cooling at S-LSR	laser, ion, electron, coupling	1360
	A. Noda, H. Fadil, S. Fujimoto, M. Ikegami, T. Shirai, M. Tanabe, H. Tongu Kyoto ICR, Uji, Kyoto M. Grieser MPI-K, Heidelberg I.N. Meshkov, E. Syresin JINR, Dubna, Moscow Region K. Noda, T. Takeuchi NIRS, Chiba-shi H. Okamoto, Y. Yuri HU/AdSM, Higashi-Hiroshima
	S-LSR is an ion accumulation and cooler ring with the circumference and maximum magnetic rigidity of 22.589 m and 1.0T.m, respectively. Electron beam cooling will be applied for laser-produced hot ion beam after phase rotation. Electron cooler for S-LSR is now under construction and the beam simulation is also going on. Laser cooling of Mg ion with low energy (35 keV) is also planned in 3-dimensional way with use of Synchro-Betatron coupling.so as to realize ultra cold beam. Cancellation of shear force due to orbit-length difference in the dipole section is to be studied with use of overlapping of the radial electric field inversely proportional to the curvature radius with the uniform vertical magnetic field. Possible experiments to approach to ultra-cold beam is also to be studied by computer simulation
TUPLT098	Vertical Beam Motion in the AGOR Cyclotron	beam-losses, proton, cyclotron, betatron	1384
	M.A. Hofstee, S. Brandenburg, H. Post, W.K. van Asselt KVI, Groningen
	Large-scale vertical excursions have been observed in the AGOR cyclotron for light ionbeams at energies close to the focussing limit (E/A =200 Q/A MeV per nucleon). With increasing radius the beam gradually moves down out of the geometrical median plane by several mm, leading to internal beamlosses. It was concluded that this effect is caused by a vertical alignment error of the coils combined with the weak vertical focussing for the beams concerned. Moving the main coils by a total of 0.37 mm has significantly improved the situation at large radii, but results in internal beamlosses for certain beams at small radii due to a large upward excursion. A systematic study of the vertical beam dynamics as a function of beam particle and energy will be presented. Possible causes and solutions will be discussed.
TUPLT133	Test Results of Injector Based on Resonance System with Evanescent Oscillations	electron, bunching, cathode, emittance	1437
	S.A. Perezhogin, M.I. Ayzatskiy, E.Z. Biller, K. Kramarenko, V.A. Kushnir, V.V. Mytrochenko, Z.V. Zhiglo NSC/KIPT, Kharkov
	Report presents results of tune-up and tests of the compact electron S ? band injector consisting of the low-voltage diode electron gun and the bunching system based on the resonant system with the evanescent oscillation. In the considered bunching system electrical field increased from beam entrance to an exit of the buncher. The injector designed for bunching of electron beam with initial energy of 25 keV and pulse current of 300 mA and accelerating it to the energy of 1 MeV.
TUPLT179	Mini-bunched and Micro-bunched Slow Extracted Beams from the AGS	extraction, simulation, kaon, proton	1544
	K.A. Brown, L. Ahrens, J.M. Brennan, J. Glenn, M. Sivertz, N. Tsoupas BNL, Upton, Long Island, New York S.R. Koscielniak TRIUMF, Vancouver
	BNL's AGS has a long history of providing slow extracted proton beams to fixed target experiments. This program of providing high quality high intensity beams continues with two new experiments currently being designed for operation at the AGS; both of these new experiments require slow extracted beam, but with an added requirement of those beams experiments require slow extracted beam, but with an added requirement of those beams experiments and initial tests have been performed. In this report we will describe the beam requirements for the two experiments, and present results of detailed simulations and initial beam tests.
TUPLT189	Dipole and Quaqdrupole Sorting for the SNS Ring	quadrupole, dipole, multipole, sextupole	1574
	D. Raparia, A.V. Fedotov, Y.Y. Lee, J. Wei BNL, Upton, Long Island, New York
	The Spallation Neutron Source (SNS) accumulator ring is a high intensity ring and must have low uncontrolled losses for hands on maintenance. To achieve these low losses one needs very tight tolerance. These tight tolerances have been achieved through shimming the magnets and sorting. Dipoles are solid core magnets and had very good field quality but magnet to magnet variation were sorted out according to ITF, since all the dipole are powered with one power supply. Typically, sorting is done to minimize linear effects in beam dynamics. Here, sorting of quadrupoles was done according to a scheme which allows to reduce unwanted strength of nonlinear resonances. As a result, the strength of sextupole resonances for our base line tune-box was strongly reduced which was confirmed by a subsequent beam dynamics simulation.
TUPLT190	Acceleration of Polarized Beams using Multiple Strong Partial Siberian Snakes	injection, extraction, polarization, betatron	1577
	T. Roser, L. Ahrens, M. Bai, E.D. Courant, J. Glenn, R.C. Gupta, H. Huang, A.U. Luccio, W.W. MacKay, N. Tsoupas, E. Willen BNL, Upton, Long Island, New York M. Okamura, J. Takano RIKEN, Saitama
	Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20 - 30 % partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.
WEXLH01	Non-destructive Beam Measurements	dipole, quadrupole, betatron, emittance	165
	M. Bai BNL, Upton, Long Island, New York
	In high energy accelerators especially storage rings, non-destructive beam measurements are highly desirable to minimize the impact on the beam quality. In principle, the non-destructive tools can be either passive detectors like Schottky, or active devices which excite either longitudinal or transverse beam motions for the corresponding measurements. An example of such a device is ac dipole, a magnet with oscillating field, which can be used to achieve large coherent betatron oscillations. It has been demonstrated in the Brookhaven AGS that by adiabatically exciting the beam, the beam emittance growth due to the filamentation in the phase space can be avoided. This paper overviews both techniques in general. In particular, this paper also presents the beam tune measurement with Schottky detector, phase advance measurement as well as non-linear resonance measurements with the ac dipoles in the Brookhaven RHIC.
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WEOALH02	Multiturn Extraction Based on Trapping in Stable Islands at CERN PS: Recent Measurement Advances	extraction, proton, octupole, emittance	173
	M. Giovannozzi, R. Cappi, S.G. Gilardoni, M. Martini, E. Métral, A. Sakumi, R.R. Steerenberg CERN, Geneva A.-S. Müller FZK-ISS-ANKA, Karlsruhe
	Recently a novel approach to perform multi-turn extraction was proposed based on beam splitting in the transverse phase space by means of trapping inside stable islands. During the year 2002 run, preliminary measurements at the CERN Proton Synchrotron with a low-intensity, single-bunch, proton beam, confirmed the possibility of generating various beamlets starting from a single Gaussian beam. The experimental campaign continued also in the year 2003 run to assess a number of key issues, such as feasibility of trapping with high-intensity beam, capture efficiency, and multi-turn extraction proper. The experimental results are presented and discussed in detail in this paper.
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WEOALH03	Installation Strategy for the LHC Main Dipoles	dipole, injection, dynamic-aperture, multipole	176
	S.D. Fartoukh CERN, Geneva
	All positions in the LHC machine are not equivalent in terms of beam requirements on the geometry and the field quality of the main dipoles. In the presence of slightly or strongly out-of tolerance magnets, a well-defined installation strategy will therefore contribute to preserve or even optimize the performance of the machine. In view of present state of the production, we have anticipated a list of potential issues (geometry, transfer function, field direction and random b3) which, combined by order of priority, have been taken into account to define a robust installation algorithm for the LHC main dipoles. Among the different possible strategies, the proposed one has been optimised in terms of simplicity and flexibility in order not to slow down and complicate the installation process. Its output is a prescription for installing the available dipoles in sequence while reducing to an absolute minimum the number of holes required by geometry or field quality issues.
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WEYLH03	Collective Effects and Instabilities in Space Charge Dominated Beams	space-charge, simulation, electron, impedance	189
	J.A. Holmes ORNL/SNS, Oak Ridge, Tennessee
	Significant progress in the detailed computational study of collective beam dynamics is being driven by the spectacular increase in computer power. To take advantage of this, sophisticated physics models are being applied to ever more realistic and detailed situations, so that it is no longer necessary to restrict computer studies to highly idealized depictions of beam dynamics questions. This presentation will illustrate the application of a number of collective beam dynamics models to a range of accelerator physics problems in high intensity proton rings. In particular, we will consider the effects of space charge, transverse and longitudinal impedances, and electron cloud formation on beam parameters, stability, halo formation, collimation and losses, and possible equilibrium configurations. Examples will be taken from PSR, the CERN PS Ring, and SNS.
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WEPLT003	The Study of 2D Sextupole Coupling Resonances at VEPP-4M	sextupole, dynamic-aperture, coupling, betatron	1819
	V.A. Kvardakov, E. Levichev, A.I. Naumenkov, P.A. Piminov BINP SB RAS, Novosibirsk
	The Study of 2D Sextupole Coupling Resonances at VEPP-4M
WEPLT018	Nonlinear Dynamics Studies at the CERN Proton Synchrotron: Precise Measurements of Islands Parameters for the Novel Multi-turn Extraction	extraction, simulation, octupole, proton	1861
	M. Giovannozzi, P. Scaramuzzi CERN, Geneva
	Recently, a novel approach to perform multi-turn extraction from a circular accelerator was proposed. It is based on adiabatic capture of particles into islands of transverse phase space generated by nonlinear resonances. Sextupole and octupole magnets are used to generate these islands, while an appropriate slow variation of the linear tune allows particles to be trapped inside the islands. Intense experimental efforts showed that the approach is indeed performing rather well. However, good knowledge of the islands properties is a key ingredient for the success of this extraction type. In this paper, a series of measurements are presented dealing with the study of islands' parameters for the fourth-order resonance, such as detuning with amplitude, fixed points' position, betatron frequency, as well as detuning with amplitude inside the islands.
WEPLT026	Dynamic Aperture Reduction from the Dodecapole Component in the LHC Main Quadrupoles and its Mechanism.	dynamic-aperture, injection, quadrupole, lattice	1885
	A.M. Lombardi, O.S. Brüning, S.D. Fartoukh, T. Risselada, F. Schmidt, A. Verdier CERN, Geneva
	The systematic dodecapole component in the Main Quadrupoles of the LHC lattice has a strong influence on the machine dynamic aperture at injection. In this paper we quantify this effect with the help of tracking studies, explain the mechanism for the loss in dynamic aperture and look into potential correction schemes. Finally, we provide an estimate for the maximum allowed systematic dodecapole component in the MQ.
WEPLT029	Intensity Dependent Emittance Transfer Studies at the CERN Proton Synchrotron	emittance, simulation, injection, synchrotron	1894
	E. Métral, C. Carli, M. Giovannozzi, M. Martini, R.R. Steerenberg CERN, Geneva G. Franchetti, I. Hofmann GSI, Darmstadt J. Qiang LBNL, Berkeley, California R.D. Ryne LBNL/CBP, Berkeley, California
	An intensive study has been undertaken since the year 2002 to understand better the various high-intensity bottlenecks of the CERN Proton Synchrotron machine. One of these limitations comes from the so-called Montague resonance. High-intensity proton synchrotrons, having larger horizontal than vertical emittance, may suffer from this fourth-order coupling resonance driven by space charge only. In particular, such resonance may lead to emittance sharing and, possibly, beam loss due to vertical acceptance limitation. Experimental observations made in the 2002 and 2003 runs on the Montague resonance are presented in this paper and compared with 3D particle-in-cell simulation results and theoretical predictions.
WEPLT038	Betatron Resonance Studies at the CERN PS Booster by Harmonic Analysis of Turn-by-turn Beam Position Data	injection, booster, coupling, simulation	1915
	P. Urschütz, M. Benedikt, C. Carli, M. Chanel, F. Schmidt CERN, Geneva
	High brightness and high intensity beams are required from the PS Booster for LHC, CNGS and ISOLDE operation. The large space charge tune spreads associated with these beams, especially at injection, require an optimized resonance compensation scheme to avoid beam blow-up and subsequent beam losses. For this a detailed knowledge on strength and phase of resonance driving terms is needed. A new measurement system has been installed to determine resonance driving terms from turn-by-turn bpm data using fast Fourier transform. The multi-turn acquisition system as well as the specific measurement conditions at the PS Booster are discussed. As an example, the measurement and compensation of the linear coupling resonance driving term is presented. Excellent agreement between measurement and simulation for resonance phase and strength was found.
WEPLT039	Measurement and Compensation of Second and Third Order Resonances at the CERN PS Booster	booster, injection, sextupole, coupling	1918
	P. Urschütz CERN, Geneva
	Space charge effects at injection are the most limiting factor for the production of high brightness beams in the CERN PS Booster. The beams for LHC, CNGS and ISOLDE feature incoherent tune spreads exceeding 0.5 at injection energy and thus cover a large area in the tune diagram. Consequently these beams experience the effects of transverse betatron resonances and efficient compensation is required. Several measurements have been performed at the PS Booster in 2003, aiming at a detailed analysis of all relevant second and third order resonances and an optimisation of the compensation scheme. Special attention was paid to the systematic 3Qy=16 resonance. To avoid this particularly dangerous resonance an alternative working point was tested. A comparison of resonance driving terms and compensation settings for both working points was made and important differences in the strengths of the resonances were found. The peculiarities when measuring third order coupling resonance driving terms are also mentioned.
WEPLT050	Frequency Map Measurements at BESSY	sextupole, storage-ring, lattice, quadrupole	1951
	P. Kuske, O. Dressler BESSY GmbH, Berlin
	With two dedicated diagnostic kicker magnets and a turn-by-turn, bunch-by-bunch beam position monitor frequency maps were measured under various operating conditions of the BESSY storage ring. Depending on the number and type of insertion devices in operation additional resonances show up. Details of the experimental setup as well as the data analysis are presented. The results will be compared with theoretical calculations which are based on the linear model of the storage ring lattice extracted from measured response matrices. Non-linear elements are added to the model in order to describe the effect of the strong sextupole magnets, the horizontal corrector magnets installed in these magnets, and of some of the insertion devices.
WEPLT052	A Method to Measure the Skew Quadrupole Strengths in the SIS-18 using Two BPMs	quadrupole, multipole, simulation, lattice	1957
	F. Franchi, T. Beier, M. Kirk, M. Moritz, G. Rumolo GSI, Darmstadt R. Tomas BNL, Upton, Long Island, New York
	In the SIS-18 of GSI a new set of skew quadrupoles has been installed to improve the multi-turn-injection. A new method based on the measurement of the resonance driving terms has been proposed to cross-check the nominal values and polarities of their gradients. Once a beam is transversely kicked, it experiences oscillations whose spectrum contains both the betatron tune line and secondary lines. The amplitude of each line is proportional to the strength of the multipoles, such as skew quadrupoles and sextupoles, present in the lattice. In this paper a recursive algorithm to derive the magnet strength from the spectral lines and the application of this method to the eight skew quadrupoles in the SIS-18 are presented.
WEPLT053	Dynamical Effects of the Montague Resonance	emittance, simulation, synchrotron, space-charge	1960
	I. Hofmann, G. Franchetti GSI, Darmstadt J. Qiang, R.D. Ryne LBNL/CBP, Berkeley, California
	In high-intensity accelerators emittance coupling, known as Montague resonance, may be an issue if the tune split is small. For static tunes within the stop-band of this fourth order space charge driven coupling the final emittances may become equal (equipartition). Using 2D computer simulation we show, however, that slow crossing of the resonance leads to merely an exchange of emittances. In 3D this is similar, if the crossing occurs over a time-scale shorter or comparable with a synchrotron period. For much slower crossing we find, instead, that the exchange may be suppressed by synchrotron motion. We explain this effect in terms of the mixing caused by the synchrotron motion.
WEPLT059	Beam Loss Modeling for the SIS100	space-charge, beam-losses, lattice, synchrotron	1978
	G. Franchetti, I. Hofmann GSI, Darmstadt
	In long term storage dynamic aperture is typically regarded as the quantity which has to be maintained sufficiently large in order to prevent beam loss. In the SIS100 of the GSI future project, a beam size occupying a large fraction of the beam pipe is foreseen. This circumstance requires a careful description of the lattice magnetic imperfections. The dynamic aperture is estimated in relation with an optimization of the SIS100 working point. For a space-charge-free bunched beam, estimates of beam loss are computed and compared with dynamic aperture. The impact of space charge will be discussed, and preliminary results on its effect on dynamic aperture and beam loss are presented.
WEPLT060	Linear Coupling Theory of High Intensity Beams	space-charge, coupling, emittance, simulation	1981
	G. Franchetti, I. Hofmann GSI, Darmstadt M. Aslaninejad IPM, Tehran
	It is planned to use linear coupling in the SIS18 in order to fully or partially equilibrate the transverse emittances before transfer to the projected SIS100 synchrotron. In this paper we show that space charge significantly modifies the coupling mechanism. In particular the width of the stop-band is dominated by the space charge tune shift for weak skew strength. The conditions are discussed, under which slow crossing of the coupling resonance leads to the desired goal of equalizing emittances while maintaining a sufficient matching of the beam to the ring and extraction optics.
WEPLT064	2-nd Order Sextupole Effects on the Dynamic Aperture in HERA-e	octupole, sextupole, luminosity, optics	1993
	M. Vogt DESY, Hamburg
	During the first year after the luminosity upgrade HERA-e was operated in a mode for which the accessible area in transverse tune space was determined by resonances driven by sextupoles in 2-nd order. It turned out that with typical total incoherent beam beam tune shifts (.05,.08) for 2 IPs this space was too small for stable operation. We have used 2-nd order canonical perturbation theory to analyze the impact of the increased sextupole strengths in the upgraded lattice on the relevant resonance strengths and the detuning. Moreover, we have studied whether it is possible to compensate the resonances with localized octupole schemes (6 or 9 independent magnets) to 1-st and 2-nd order, computed the resulting detuning and compared the results with 6D tracking.
WEPLT067	Space Charge Problem in Low Energy Super-conducting Accelerator	focusing, space-charge, linac, simulation	2002
	N.E. Vasyukhin, R. Maier, Y. Senichev FZJ/IKP, Jülich
	At present the super-conducting option of linear accelerators is considered for low energy, and new type of RF cavities is considered for this purpose. However, together with electrodynamics problems we should solve the transverse stability problem, since in structures with external focusing elements the focusing period is longer, and in higher accelerating field the defocusing factor increases as well. In this paper we consider the transverse stability problem, taking into account the non-linear space charge problem. The fundamental mechanism of hallo creation in super-conducting linear accelerators is investigated to minimize the particle losses. The theoretical results are supported by numerical simulation.
WEPLT071	Longitudinal Resonances and Emittance Growth Using QWR/HWR in a Linac	linac, emittance, focusing, transverse-dynamics	2014
	P. Bertrand GANIL, Caen
	In the frame of the SPIRAL II project at GANIL, we present an analytical approach allowing us to understand in a simple way the longitudinal behaviour of a beam , transmitted in bunching mode or accelerated in a Linac designed with QWR or HWR cavities. In particular, we make appear the strong relationship with the Henon map properties.
WEPLT079	Non Linear Beam Dynamics and Lifetime on the SOLEIL Storage Ring	undulator, insertion, insertion-device, focusing	2035
	P. Brunelle, A. Loulergue, A. Nadji, L.S. Nadolski SOLEIL, Gif-sur-Yvette
	The incidence of several non-linear effects on the energy acceptance and beam lifetime has been investigated, using the BETA and TRACY II tracking codes. The effect of all magnets multipolar components has been checked on the working point (18.20; 10.30), especially the decapolar component induced by the H-corrector. The dipolar field, which is created by additional coils in the sextupoles, generates a significant decapolar component which, associated to the distributed dispersion, can reduce significantly the dynamic acceptance at large energy deviations. This effect depends on the natural closed orbit to be corrected: corrector strengths and cross talk between the different decapolar components. Moreover, the sensitivity to the number of correctors, used for correction, has been evaluated. The effect of insertions devices has also been studied, integrating field maps generated by the RADIA code into the tracking codes. With undulators, such as an in-vacuum U20 and an Apple II type HU80 (with different polarization modes), it was shown that the transverse field in-homogeneity and the focusing effects generating beta-beat can affect severely the energy acceptance and the beam lifetime because of resonance excitation.
WEPLT084	Experimental Frequency Maps for the ESRF Storage Ring	kicker, storage-ring, dynamic-aperture, optics	2050
	Y. Papaphilippou, L. Farvacque, E. Plouviez, J.-L. Revol, A. Ropert ESRF, Grenoble J. Laskar IMCCE, Paris Ch. Skokos Academy of Athens, Athens
	Experimental frequency maps have already revealed many unknown characteristics of the ESRF storage ring non-linear dynamics. In the past year, several efforts were undertaken in order to establish this technique as an operational on-line tool. The acquisition time was significantly reduced by collecting data from a dedicated fast BPM system. The problem of beam decoherence was limited by establishing a method for accurate tune determination in a small number of turns, using the information from all the BPMs around the ring. The possibility to explore the off-momentum dynamics by exciting the beam, with synchronous transverse and longitudinal kicks was also investigated. Finally, measurements of resonance driving term amplitudes and phase advances were used to identify the efficiency of resonance corrections.
WEPLT090	Nonlinear Evolution of the Beam in Phase Space at Elettra	betatron, beam-losses, coupling, dynamic-aperture	2059
	S. Di Mitri, L. Tosi ELETTRA, Basovizza, Trieste
	Phase space in the Elettra storage ring has been investigated. The beam is kicked and the coordinates of the bunch centroid are acquired for at least 1000 turns. A Hilbert transform has been used to deduce the evolution of beam phase space from position coordinates. Several nonlinear effects have been detected, such as the amplitude dependence of the betatron tune, the presence of high order and coupling resonances. Fixed points have been evidenced as well as the behaviour of the beam in their neighbourhood. Scans in lifetime versus tune confirm the limiting effect of the observed resonances on the region of regular motion.
WEPLT091	Frequency Map Analysis with the Insertion Devices at ELETTRA	insertion, insertion-device, simulation, lattice	2062
	S. Di Mitri, L. Tosi ELETTRA, Basovizza, Trieste L.G. Liu SSRF, Shanghai
	Frequency map analysis is a very efficient technique for the understanding of the resonances which may affect the stability of the electrons. Measurements correlated to simulations can provide a method to improve beam lifetime and injection efficiency that is particulary important in the case of top up operation. In this paper, the results of frequency map measurements and simulations for the ELETTRA storage ring are presented both for the bare lattice as well as for the case in which insertion devices are operational.
WEPLT101	On-line Mechanical Instabilities Measurements and Tuner Development in SC Low-beta Resonators	linac, feedback, vacuum, injection	2086
	A. Facco, E. Bissiato, S. Canella, D. Carlucci, M. Lollo, F. Scarpa, D. Zenere INFN/LNL, Legnaro, Padova
	The use of high-Q and small rf bandwidth superconducting quarter wave resonators made of bulk niobium put severe requirements to the helium bath pressure stability to avoid cavity detuning. This is not always possible, and cavity detuning caused by slow pressure changes must be precisely followed by the cavity tuner. The LNL philosophy is based on mechanical damping of cavity vibrations and mechanical tuning in feedback for slow frequency compensation. The old-fashioned tuners installed in the ALPI linac had significant performance limitations. To replace them, we have designed, constructed and tested a new tuner which integrates the LNL system and control with the TRIUMF, backlash-free tuner leverage design. The new tuner is designed to compensate pressure changes up to 100 mbar/minute with a precision of 0.5 Hz, and it will be installed in the ALPI resonators. An upgraded prototype for future applications includes a piezoelectric actuator for fast tuning. Tuner characteristics and first test results will be presented. This system is extendable to other low-beta cavity types like superconducting rfqs.
WEPLT107	Nonlinear field Effects in the JPARC Main Ring	sextupole, injection, betatron, space-charge	2101
	A.Y. Molodojentsev, S. Machida, Y. Mori KEK, Ibaraki
	Main Ring (MR) of the Japanese Particle Accelerator Research Complex (JPARC) should provide acceleration of the high-intensity proton beam from the energy of 3GeV to 50 GeV. The expected beam intensity is 3.3·1014 ppp and the repetition rate is about 0.3 Hz. The imaginary transition lattice of the ring was adopted, which has the natural linear chromaticity about (-30) for both transverse phase planes. The expected momentum spread of the captured particles before the acceleration is less than 0.007. Two independent families of the chromatic sextupole magnets are use to eliminate the linear chromatic tune shift. This chromatic sextupole field nonlinearity will excite the normal 'octupole' resonances and will lead to the amplitude dependent tune shifts in both transverse phase planes. Additional sextupole magnets are planed to excite the third-order horizontal resonance, which will be used for the slow extraction. Incoherent tune shift of the low-energy proton beam is about (-0.16) so that some particles could cross nearest low-order resonances. Optimization of the 'bare' working point of MR at the injection energy has been performed to minimize the influence of the linear coupling and high-order coupling resonances. Excitation of the linear coupling resonance has been introduced by the realistic misalignment errors adopted for MR. The 'bare' working point during the slow extraction has been analyzed. The influence of the normal sextupole resonances on the large amplitude particle behavior at the scraper location has been studied including random sextupole field component of the MR bending magnets. Realistic distortion of the ideal ring super-periodicity by the injection kicker magnets has been included in the tracking procedure for the on- and off-momentum particles. Finally, correction schemes have been considered for most dangerous resonances around the optimized 'bare' working point. The space-charge effects of the proton beam have not been included in this study.
WEPLT114	Field Measurements in the AGS Warm Snake	dipole, coupling, simulation, betatron	2116
	J. Takano, M. Okamura RIKEN, Saitama R. Alforque, R. Belkin, G. Ganetis, A.K. Jain, W.W. MacKay, T. Roser, R. Thomas, J. Tuozzolo BNL, Upton, Long Island, New York T. Hattori RLNR, Tokyo
	A new warm snake has been produced for avoiding the transverse coupling resonance in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). The warm snake is the world?s first normal conducting helical dipole partial snake which has a double pitch structure to allow spin rotation with no net beam offset or deflection with a single magnet. The warm snake is 2.6m long, and has a field of 1.5 Tesla for a 9 degrees spin rotation. The pitches, current density, and shims were optimized by using OPERA_3D / TOSCA. The magnetic field harmonics have been measured using a system of 51 mm long, 34 mm radius tangential coils. The axial variation of the dipole field angle agrees very well with the calculations, indicating no significant construction errors. However, the measured transfer function shows a discrepancy of 4% which may be caused by BH-curve differences, deformation of the iron and packing factor of the laminations. To correct the beam trajectory the operating current was adjusted and shims were installed on the end plates. These optimization studies, and comparison with measurements, will be shown.
WEPLT115	A Study of Transverse Resonance Crossing in FFAG	simulation, beam-losses, emittance, acceleration	2119
	M. Aiba University of Tokyo, Tokyo S. Machida, Y. Mori KEK, Ibaraki
	A study of "resonance crossing" in FFAG accelerator is described in this paper. A deviation of FFAG guiding field in actual magnet breaks zero chromaticity condition, and tunes cross resonance while acceleration. In order to avoid a critical beam loss or emittance growth, nominal tune should be chosen so as not to cross low-order resonances. However, crossing higher order resonance can be critical and that depends on the parameters such as crossing speed, excitation magnitude and initial beam emittance. We will present analytical model and simulation study in various parameter space.
WEPLT121	Computer Simulation of Equilibrium Electron Beam Distribution in the Proximity of 4th Order Single Nonlinear Resonance	simulation, electron, radiation, storage-ring	2137
	T.-S. Ueng, C.-C. Kuo, H.-J. Tsai NSRRC, Hsinchu A. Chao SLAC, Menlo Park, California
	The beam distribution of particles in an electron storage ring is distorted in the presence of nonlinear resonances. A computer simulation is used to study the equilibrium distribution of an electron beam in the presence of 4th order single nonlinear resonance. The results are compared with that obtained using an analytical approach by solving the Fokker-Planck equation to first order in the resonance strength. The effect of resonance on the quantum lifetime of electron beam is also compared and investigated.
WEPLT168	ORBIT Benchmark of Space-charge-induced Emittance Growth in the CERN PS	emittance, simulation, lattice, space-charge	2221
	S.M. Cousineau, J.A. Holmes ORNL/SNS, Oak Ridge, Tennessee E. Métral CERN, Geneva
	Particle tracking codes provide an invaluable tool in the design and operation of high intensity machines. An important task in the development of these codes is the validation of the space charge models through benchmark with experimental data. Presented here are benchmarks of the ORBIT particle tracking code with recent measurements of space-charge-induced transverse emittance growth in the CERN PS machine. Benchmarks of two experimental data sets are performed: Integer resonance crossing, and Montague resonance crossing.
WEPLT181	Measurement of Multipole Strengths from RHIC BPM Data	dipole, multipole, lattice, betatron	2242
	R. Tomas, M. Bai, W. Fischer BNL, Upton, Long Island, New York F. Franchi, G. Rumolo GSI, Darmstadt
	Recently resonance driving terms were successfully measured in the CERN SPS and the BNL RHIC from the Fourier spectrum of BPM data. Based on these measurements a new analysis has been derived to extract multipole strengths.In this paper we present experimental measurements of sextupolar and skew quadrupolar strengths carried out at RHIC. Also discussed is the possibility of a non-destructive measurement using an AC dipole.
THXCH01	Achieving Sub-micron Stability in Light Sources	feedback, quadrupole, photon, storage-ring	211
	M. Böge PSI, Villigen
	One of the major goals for present and future light sources is to achieve sub-micron orbit stability of the electron beam at the photon beam source points over a large frequency range. This puts tight constraints on the design of the various accelerator components like girders, magnets, power supplies and diagnostic hardware. Fast orbit feedbacks systems based on high performance RF- and X-BPMs become essential to suppress residual orbit distortions. Furthermore the "top-up" operation mode which guaranties a constant electron beam current and thus a constant heat load in 3rd generation light sources is one of the key ingredients to reach sub-micron stability.
	Video of talk
	Transparencies
THOACH01	SPEAR3 Commissioning	dynamic-aperture, closed-orbit, storage-ring, feedback	216
	J.A. Safranek, S. Allison, P. Bellomo, W.J. Corbett, M. Cornacchia, E. Guerra, R.O. Hettel, D. Keeley, N. Kurita, D.J. Martin, P.A. McIntosh, H. Morales, G.J. Portmann, F.S. Rafael, H. Rarback, J.J. Sebek, T. Straumann, A. Terebilo, J. Wachter, C. Wermelskirchen, M. Widmeyer, R. Yotam SLAC/SSRL, Menlo Park, California M.J. Boland, Y.E. Tan ASP, Melbourne J.M. Byrd, D. Robin, T. Scarvie, C. Steier LBNL/ALS, Berkeley, California M. Böge PSI, Villigen H.-P. Chang, C.-C. Kuo, H.-J. Tsai NSRRC, Hsinchu W. Decking DESY, Hamburg M.G. Fedurin, P. Jines LSU/CAMD, Baton Rouge, Louisiana K. Harkay, V. Sajaev ANL/APS, Argonne, Illinois S. Krinsky, B. Podobedov BNL/NSLS, Upton, Long Island, New York L.S. Nadolski SOLEIL, Gif-sur-Yvette A. Ropert ESRF, Grenoble M. Yoon POSTECH, Pohang, Kyungbuk
	Starting in April, 2003, the SPEAR2 storage ring was removed and replaced with a new 500 mA, 3 GeV light source, SPEAR3. The SPEAR2 storage ring had been in use for high energy physics, then synchrotron radiation since 1972. Commissioning of SPEAR3 started on December 8, 2003 and synchrotron radiation will be delivered to the first users on March 8, 2004. SPEAR3 commissioning will be reviewed, including discussion of diagnostics, orbit control, optics correction and high current studies.
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THPKF002	Linac RF Control System for CANDLE. Design and Simulation	linac, simulation, feedback, electron	2257
	A. Vardanyan, G. Amatuni CANDLE, Yerevan
	The design and constructional features of the control system for 500 MHz and 3 GHz RF system of CANDLE linac are presented. The linac includes an electron gun that is modulated by 500 MHz generator to produce 1 ns electron bunches, 500 MHz and 3 GHz bunchers, pre-accelerating cavity and the main accelerating section at 3 GHz. An important feature of the presented control system is a high level synchronization of amplitude-phase characteristics of the sub-systems that provide the required energy-space characteristics of the accelerated beam. This puts strict requirements on RF frequency, amplitude and phase stabilization. A digital feedback system has been adopted to provide flexibility in the control algorithms. The main feature is a 9 MHz sampling rate for the cavity signals and digital I/Q detection. The design was performed using the RF analyze tool, based on MATLAB SIMULINK, which allows the simulation and analyzes of the field regulation quality. The simulation results for CANDLE Linac RF system, based on the output parameters of electron beam are given.
THPKF011	Vibration Measurements at the Swiss Light Source (SLS)	quadrupole, site, ground-motion, lattice	2278
	S. Redaelli, R.W. Assmann, W. Coosemans CERN, Geneva M. Böge, M. Dehler, L. Rivkin PSI, Villigen
	Vibration measurements have been carried out at the Swiss Light Source (SLS) site as part of a collaboration between the Paul Scherrer Institute (PSI) and the European Organization for Nuclear Research (CERN). The vibration level of the SLS floor and of some lattice elements of the SLS ring have been monitored under various experimental conditions. In particular, vibration spectra of lattice quadrupoles have been measured with a circulating beam and compared with the spectra of transverse beam positions, as measured with beam position monitors. This paper summarizes the results.
THPKF022	Energy Calibration of the ANKA Storage Ring	synchrotron, storage-ring, energy-calibration, synchrotron-radiation	2311
	A.-S. Müller, I. Birkel, E. Huttel, M. Pont, F. Pérez, R. Rossmanith FZK-ISS-ANKA, Karlsruhe
	The ANKA electron storage ring operates in the energy range from 0.5 to 2.5 GeV. An energy calibration using the method of resonant spin depolarisation yields the exact beam energy of ANKA. In addition this method allows to determine other parameters such as nonlinear momentum compaction factor and incoherent synchrotron tune with extraordinary precision. This paper discusses experimental set-up and energy measurements. The reproducibility of the ANKA beam energy is addressed as well as energy drifts caused by thermal expansion of the floor.
THPLT028	High Precision Cavity Beam Position Monitor	dipole, background, coupling, damping	2535
	A. Liapine, H. Henke TET, Berlin
	A cavity beam position monitor is proposed for measuring the beam deflection in the TESLA energy spectrometer. The precision of the measurement has to be better than 1 micrometer. A slotted cavity is chosen as pick-up in order to reject the background signals and enhance the precision and the dynamic range of the monitor. The paper gives the design overview for two prototypes with operating frequencies of 1.5 GHz and 5.5 GHz, respectively. The results obtained on the test bench with direct conversion electronics are presented. A resolution of about 100 nm was achieved.
THPLT064	Enhancement of Laser Power from a Mode Lock Laser with an Optical Cavity	laser, electron, scattering, target	2637
	M. Nomura, K. Hirano, M. Takano NIRS, Chiba-shi S. Araki, Y. Higashi, T. Taniguchi, J. Urakawa, Y. Yamazaki KEK, Ibaraki Y. Honda, N. Sasao, K. Takezawa Kyoto University, Kyoto H. Sakai ISSP/SRL, Chiba
	We have developed a laser-wire beam monitor to measure a beam profile in the KEK/ATF damping ring. This monitor is based on the inverse Compton scattering with a thin wire of the laser. The laser-wire is produced with a Fabry-Perot optical cavity in which laser power from a CW laser is stored and enhanced up to 1000 times. We have a plan to increase a gamma ray flux by using a pulsed laser instead of the CW laser. There are many applications for such a high flux gamma ray, e.g. medical use, transmutation and so on. We have done a test experiment of laser pulse stacking with a mode lock laser where wavelength is 1064 nm, repetition rate 357MHz, pulse width 7psec(FWHM) and a 42 cm long Fabry-Perot optical cavity. The experimental results show that laser power in the optical cavity can be enhanced by laser pulse stacking.
THPLT162	Diagnosis of Coupling and Beta Function Errors in the PEP-II B-Factory	coupling, betatron, lattice, storage-ring	2840
	M.H. Donald, T.M. Himel, S. Zelazny SLAC, Menlo Park, California
	The SLAC Control program has an automatic phase measuring system whereby the beta functions of the two storage rings are measured. This facility has recently been extended to measure coupling between the horizontal and vertical motion and to fit the measured values to their modes of propagation. This facility aids the diagnosis and correction of coupling and focusing errors.