polarization

Paper	Title	Other Keywords	Page
MOPKF004	Magnet Sorting Algorithm Applied to the LNLS EPU	undulator, radiation, wiggler, permanent-magnet	303
	X.R. Resende, R.M. Dias LNLS, Campinas
	The Brazilian Synchrotron Light Laboratory is about to begin the construction of the first Undulator for its 1.37 GeV electron storage ring. This device will be of the EPU type with a period of 50 milimeters and 22 milimeters minimum magnetic gap. In this work we report on the sorting algorithm applied in the construction of a 10-period undulator prototype.
MOPKF010	The Output Performance of the BESSY Multi-stage HGHG-FEL	bunching, undulator, electron, laser	318
	A. Meseck, M. Abo-Bakr, B.C. Kuske BESSY GmbH, Berlin
	The BESSY soft X-ray FEL is planned as a High Gain Harmonic Generatio(HGHG) FEL multi-user facility covering the VUV to soft X-ray spectral range(0.02 keV - 1. keV). A photoinjector and a superconducting 2.3GeV CW linac will feed three independent HGHG-FEL-lines. As the efficiency of the interaction between the radiation and the electron beam is higher in a helical undulator, one would tend to prefer such a device for the HGHG scheme. Also a higher K-value of the modulators seems to be advantageous. This is not necessarily the case. We present simulation studies for the BESSY-HGHG-FELs and discuss the output performance for ‘‘helical stages'' and increased K value of the modulators.
MOPKF020	Proposal for a Sub-100 fs Electron Bunch Arrival-time Monitor for the VUV-FEL at DESY	laser, electron, simulation, undulator	345
	H. Schlarb, S. Düsterer, J. Feldhaus, J. Hauschildt, R. Ischebeck, K. Ludwig, B. Schmidt, P. Schmüser, S. Simrock, B. Steffen, F. Van den Berghe, A. Winter DESY, Hamburg P.H. Bucksbaum, A. Cavalieri, D. Fritz, S. Lee, D. Reis Michigan University, Ann Arbor, Michigan
	For pump-probe experiments at the VUV-Free Electron Laser at DESY, an external optical laser system will be installed, capable of delivering ultra-short pulses of high intensity. The laser pulses with a center wavelength of 800 nm are synchronized with the VUV-FEL beam which covers the wavelength range between 6 nm and 80 nm. The expected pulse durations are typically 100 fs FWHM or below. For high-resolution pump-probe experiments a precise knowledge of the time difference between both pulses is mandatory. In this paper we describe the layout and the design of a high-precision electron bunch arrival time monitor based on an electro-optic technique. We present the numerical results of simulations that include: the laser propagation in a specifically designed demanding optical system, the laser transport through a 150 m long optical fibre, the electro-optically induced effect in different types of crystals and for different electron bunch shapes as well as the effects of wake fields on the co-propagating electric-fields and their impact on the observable signals.
MOPKF025	Planar and Planar Helical Superconductive Undulators for Storage Rings, State of the Art	undulator, vacuum, storage-ring, synchrotron	354
	R. Rossmanith, A. Bernhard, B.K. Kostka FZK-ISS-ANKA, Karlsruhe D. Dölling, A. Hobl, D. Krischel, S. Kubsky ACCEL, Bergisch Gladbach U. Schindler, E. Steffens Erlangen University, Erlangen T. Schneider FZ Karlsruhe, Karlsruhe
	Planar superconductive undulators for low beam currents were successfully tested in the past. In a next step devices suitable for small gaps in storage rings are in preparation. The tests will clarify experimentally the heat load generated by the beam in the cold bore and will allow to optimize the control system of such devices. In addition, the layout of the next generation of planar superconductive undulators with electrically variable polarization direction are introduced in this paper.
MOPKF031	SOLEIL Insertion Devices: The Progress Report	undulator, insertion, insertion-device, radiation	369
	O.V. Chubar, C. Benabderrahmane, A. Dael, M.-P. Level, O. Marcouillé, M. Massal SOLEIL, Gif-sur-Yvette
	The French national synchrotron radiation source SOLEIL is planned to start operation in 2006 with several different insertion devices installed in the storage ring either from "day one" or within the first year. The list of high-priority insertion devices includes: 3 planar hybrid in-vacuum undulators with the period of 20 mm; 3 Apple-II type PPM undulators with the period of 80 mm; 3 electromagnet elliptical undulators with the period of 256 mm, and a 640 mm period elliptical electromagnet undulator offering advanced possibilities for fine-tuning of polarization states of the emitted radiation. The emission of all these undulators is covering wide spectral range extending from hard X-rays to UV. Pre-design of the IDs was done by SOLEIL. The construction will be done by industrial companies and institutions with production capabilities. Magnetic assembly of the Apple-II and in-vacuum undulators is planned to be done in collaboration with ELETTRA and ESRF. The final magnetic measurements of all the IDs will be made in the SOLEIL magnetic measurements laboratory. The paper will present peculiarities of the magnetic design, calculated maximum-flux spectra and associated heat load in various modes of operation.
MOPKF053	Pulsed-wire Method of Field Measurement on Short Elliptically Polarized Undulator	undulator, radiation, synchrotron, alignment	428
	T.-C. Fan, C.-S. Hwang, F.-Y. Lin NSRRC, Hsinchu
	With two sets of photo illuminator and detector, scientists already have applied pulsed-wire method to measure the magnetic field along two mutually perpendicular directions. Two-dimensional pulsed-wire method is useful for the test of elliptically polarlized undulator (EPU). We tried to use this method to observe the first integral and second integral fields of a short EPU in real time during the polarization tuning. We have taken care more details than the pulsed-wire measurement of planner undulators. The phase difference, the relative field strength along two direction as well as the precise centerline can be achieved.
MOPKF071	Study of Row Phase Dependent Skew Quadrupole Fields in Apple-II type EPUs at the ALS	quadrupole, undulator, focusing, lattice	479
	C. Steier, S. Marks, S. Prestemon, D. Robin, R.D. Schlueter, A. Wolski LBNL, Berkeley, California
	Since about 5 years, Apple-II type Elliptically Polarizing Undulators (EPU) have been used very successfully at the ALS to generate high brightness photon beams with arbitrary polarization. However, both EPUs installed so far cause significant changes of the vertical beamsize, especially when the row phase is changed to change the polarization of the photons emitted. The effect has been measured in detail and turned out to be caused by a row phase dependent skew quadrupole term in the EPUs. Magnetic measurements revealed the same effect for the third EPU to be installed later this year. All measurements to identify and quantify the effect with beam will be presented, as well as results of magnetic bench measurements and numeric field simulations.
MOPLT059	Design Options for the RF Deflector of the CTF3 Delay Loop	klystron, simulation, coupling, linac	689
	F. Marcellini, D. Alesini INFN/LNF, Frascati (Roma)
	Injection and extraction of bunch trains in the CTF3 Delay Loop for the recombination between adjacent bunch trains is performed by a specially designed RF deflector. A standing wave structure has been chosen. Three possible solutions have been studied and designed, and a comparative analysis is presented. All of them satisfy the essential requirements of the system up to the maximum foreseen energy with the existing klystron.
MOPLT087	Research of Possibility to use Beam Polarization for Absolute Energy Calibration in High-precision Measurement of Tau Lepton Mass at VEPP-4M	resonance, 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).
MOPLT091	Accelerator Physics Issues of the VEPP-4M at Low Energy	luminosity, electron, wiggler, diagnostics	749
	V.V. Smaluk BINP SB RAS, Novosibirsk
	The VEPP-4M electron-positron collider is being prepared for a new high-energy physics run in the 1.5 - 2.0 GeV energy range. During the first run (2001-2002), precision mass measurements of the J/psi and psi' mesons using the KEDR detector have been carried out with a record accuracy. To provide high performance, efforts for investigation and further development of the machine have been done. The most important results are described. A record absolute accuracy of energy measurement was achieved using the resonant depolarization method. A possibility to use this method for the absolute energy calibration in tau-lepton mass measurements is studied. For the first time, the Moeller polarimeter based on an internal polarized gas jet target has been developed and successfully used at the VEPP-3 booster storage ring. A system of energy measurement using Compton back-scattering has been put into operation. To increase the machine luminosity, operation with dipole wigglers is studied, and a project of turn-by-turn feedback system to suppress beam instabilities has been started. For beam diagnostics, a multi-anode photomultiplier tube and a white light coronograph were installed. The VEPP-4M operation experience with the longitudinal magnetic field within the KEDR detector is also described.
MOPLT148	Progress of the eRHIC Electron Ring Design	electron, emittance, luminosity, proton	887
	F. Wang, M. Farkhondeh, W. Franklin, W. Graves, R. Milner, C. Tschalaer, J. Van der Laan, D. Wang, A. Zolfaghari, T. Zwart MIT/BLAC, Middleton, Massachusetts D.P. Barber DESY, Hamburg C. Montag, S. Peggs, V. Ptitsyn BNL, Upton, Long Island, New York A.V. Otboev, Y.M. Shatunov BINP SB RAS, Novosibirsk J. Shi KU, Lawrence, Kansas
	Over the past year, a baseline design of the electron ring for the eRHIC hadron-lepton collider has been developed.This site-specific design is based on the understanding of the existing RHIC machine performance and its possible upgrades.The design includes a full energy polarized electron beam injector to ensure operational reliability and to provide high integrated luminosity.The electron ring energy range is 5 to 10 GeV.The electron beam emittance, the electron beam path length and the interaction region optics have to be adjusted over a wide range to match the hadron beam of various species and variable energies.We describe the expected machine perfomance, the interaction region and the lattice design. We also discuss the possible approaches leading to the 1033 cm-2s-1 luminosity for the collisions between 10 GeV polarized electron beam and 250 GeV polarized proton beam.
MOPLT167	RHIC Operation with Longitudinally Polarized Protons	resonance, 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.
TUXLH03	RHIC Performance and Plans Towards Higher Luminosity and Higher Polarization	electron, luminosity, proton, ion	98
	T. Satogata BNL, Upton, Long Island, New York
	RHIC is the first hadron collider consisting of two independent rings. It is designed to operate over a wide range of beam energies and species, including polarized protons, heavy ions, and asymmetric beam collisions. RHIC has produced physics data at four experiments since 1999 in runs that include gold-on-gold collisions at design beam energy (100 GeV/u), high-energy polarized proton-proton collisions (100 GeV on 100 GeV), and deuteron-gold collisions (100 GeV/u). Recent machine performance will be reviewed for high-luminosity gold-gold operations and polarized proton operations, including causes and solutions for known operational limits. Plans and progress for luminosity and polarization improvements, electron cooling, and the electron-ion collider eRHIC will be discussed.
	Video of talk
	Transparencies
TUPKF012	A HOM Damped Planar Accelerating Structure	damping, dipole, impedance, coupling	982
	A. Blednykh, H. Henke TET, Berlin
	The problem of very fast higher order mode (HOM) suppression, in the order of 1ns, was investigated for a planar 30GHz accelerating structure. Both, damping and detuning were considered. A sufficient suppression could be achieved by damping waveguides in every cell in vertical and in horizontal direction. Finally, a scaled-up 10GHz model was built. It is a 35 cm long aluminum structure, which was machined by high-precision milling. In order to reduce the surface gradient on the input/output coupling irises a symmetrical RF coupler was developed. The HOM damping is accomplished by coupling six damping waveguides to each accelerating cell. The waveguides are loaded by a low resitivity RF load. The whole structure with waveguides and loads was optimized by means of the computer code GdfidL. The paper gives the design criteria and the results of s-parameter and bead-pull measurements.
TUPLT037	Dispersion Correction in HERA	closed-orbit, luminosity, positron, electron	1228
	J. Keil, W. Decking DESY, Hamburg
	The electron-proton collider HERA at the DESY laboratory in Hamburg has been in operation since 1991. After the luminosity upgrade of HERA in 2001 the control of the horizontal and vertical dispersion function of the positron beam became more important than before. Deviations from the design dispersion in the horizontal plane can change the emittance of the electron beam significantly thus leading to a reduction of the luminosity. For optimizing the polarization of the electron beam the reduction of vertical orbit and dispersion deviations is important. In this paper the combined dispersion and orbit correction in HERA is described and first results are reported.
TUPLT043	Status of the Cooler Synchrotron COSY-Juelich	injection, proton, electron, dipole	1246
	B. Lorentz, U. Bechstedt, J. Dietrich, R. Eichhorn, R. Gebel, A. Lehrach, R. Maier, D. Prasuhn, A. Schnase, H. Schneider, R. Stassen, H. Stockhorst, R. Tölle FZJ/IKP, Jülich
	The cooler synchrotron COSY accelerates and stores unpolarized and polarized protons and deuterons in the momentum range between 300 MeV/c to 3.65 GeV/c. To provide high quality beams, an Electron Cooler at injection and a Stochastic Cooling System from 1.5 GeV/c up to maximum momentum are available. Vertically polarized proton beams with a polarization of more than 0.80 are delivered to internal and external experimental areas at different momenta. Externally, the maximum momentum is up to date restricted to approximately 3.4 GeV/c by the extraction elements installed in COSY. In 2003 deuteron beams with different combinations of vector and tensor polarization were made available for internal and external experiments. An rf dipole was installed, which is used to induce artificial depolarizing resonances. It can be used for an accurate determination of the momentum of the stored beams. The status of the cooler synchrotron COSY is presented and future plans are discussed.
TUPLT163	Achieving Beam Quality Requirements for Parity Experiments at Jefferson Lab	feedback, electron, damping, target	1509
	Y.-C. Chao, H. Areti, F.J. Benesch, B. Bevins, S.A. Bogacz, S. Chattopadhyay, J.M. Grames, J. Hansknecht, A. Hutton, R. Kazimi, L. Merminga, M. Poelker, Y. Roblin, M. Tiefenback Jefferson Lab, Newport News, Virginia D. Armstrong The College of William and Mary, Williamsburg D. Beck, K. Nakahara University of Illinois, Urbana K. Paschke University of Massachusetts, Amherst M. Pitt Virginia Polytechnic Institute and State University, Blacksburg
	Measurement of asymmetry between alternating opposite electron polarization in electron-nucleon scattering experiments can answer important questions about nucleon structures. Such experiments impose stringent condition on the electron beam quality, and thus the accelerator used for beam creation and delivery. Of particular concern to such ?parity? experiments is the level of correlation between beam characteristics (orbit, intensity) and electron polarization that can obscure the real asymmetry. This can be introduced at the beam forming stage, created due to scraping, or not damped to desired level due to defective transport. Suppression of such correlation thus demands tight control of the beam line from cathode to target, and requires multi-disciplined approach with collaboration among nuclear physicists and accelerator physicists/engineers. The approach adopted at Jefferson Lab includes reduction of correlation source, improving low energy beam handling, and monitoring and correcting global transport. This paper will discuss methods adopted to meet the performance criteria imposed by parity experiments, and ongoing research aimed at going beyond current performance.
TUPLT190	Acceleration of Polarized Beams using Multiple Strong Partial Siberian Snakes	resonance, injection, extraction, 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.
THPLT005	Ultra-high Frequency Scanning Cavities for Non-relativistic Electron Beam	electron, target, impedance, single-bunch	2466
	G.G. Oksuzyan, E.D. Gazazyan, A.T. Margaryan, A.D. Ter-Poghosyan YerPhI, Yerevan M. Ivanyan CANDLE, Yerevan
	The different scanning schemes based on the RF cavities for non-relativistic electron beam are examined. Optimization criteria for various types of cavities were developed. A complete picture of the beamscanning at a given point of interest is obtained.
THPLT046	The Synchrotron Radiation Beamline at TTF2	radiation, synchrotron, synchrotron-radiation, electron	2586
	O. Grimm, S. Casalbuoni, L. Fröhlich, O. Peters, J. Rossbach DESY, Hamburg
	The VUV-FEL at DESY, Hamburg, will require novel techniques to characterize the longitudinal charge distribution of the electron bunches that drive the free-electron laser. Conventional methods are inadequate at the short bunch lengths that will be obtained. One technique under study uses coherent far-infrared radiation to reconstruct the bunch shape through Fourier analysis of the spectrum. In a first step, a beam line to guide both far-infrared (50-1000 um) and optical synchrotron radiation from one of the bunch compressor magnets of the linear accelerator to a diagnostic station outside of the controlled area is currently under construction. It will also allow a comparison between streak camera and far-infrared measurements for features on length scales above some 100 um (the streak camera resolution). Later, infrared techniques extending to shorter wavelengths, i.e. to shorter bunch lengths, will also be used further downstream the accelerator, employing synchrotron, transition and undulator radiation. The beam line design, measurement principle and first measurements will be presented.
THPLT106	Measurement of Beam Polarization in VEPP-3 Storage Ring using Internal Target-based Moeller Polarimeter	target, electron, background, scattering	2730
	A.V. Grigoriev, V. Kiselev, E.V. Kremyanskaya, E. Levichev, S.I. Mishnev, S.A. Nikitin, D.M. Nikolenko, I.A. Rachek, Y.V. Shestakov, D.K. Toporkov, V.N. Zhilich BINP SB RAS, Novosibirsk
	A method for beam polarization measurement in a storage ring has been for the first time developed and applied based on measuring the asymmetry in scattering of polarized beam electrons on the internal polarized gas jet target. Using this method we have studied the polarization in VEPP-3 booster storage ring. VEPP-3 is the source of polarized beams for VEPP-4M electron-positron collider in the planned experiment on high-precision mass measurement of tau-lepton near the production threshold of the latter (1777 MeV). Radiative polarization of beams obtained in VEPP-3 is used for absolute calibration of particle energy by the resonant depolarization technique after injection into VEPP-4M ring. The polarimeter design is described. Results of polarization measurements performed in 60 MeV range of VEPP-3 energy contiguous from above to tau-lepton production threshold are presented and discussed. The depolarizing influence of the integer machine spin resonance (1763 MeV) as well as of the combination spin resonances with the betatron frequencies are found to be significant.