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ESRF

  
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TUYFI02 Latest Developments on Insertion Devices undulator, wiggler, permanent-magnet, electron 969
 
  • P. Elleaume, J. Chavanne
    ESRF, Grenoble
  A review will be carried out of the developments on Insertion Devices that have taken place world wide in the last few years. These include the development of long period electro-magnet undulators, the operational results of a number of Apple-II undulators, the development of superconducting short period multipole wigglers, as well as the construction and operation of several in-vacuum undulators. The construction of a large number of competitive middle energy synchrotron sources in the hard X-ray range means that the need to increase the photon energy in the fundamental peak of an undulator is becoming a very important issue. Two main development strategies are currently being investigated. One consists of using superconducting undulator technology, the other of a further refinement of the in-vacuum undulator permanent magnet technology with cryogenic cooling of the magnetic assembly. The issues and challenges that are part of each approach will be presented, together with the latest results.  
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TUPCH099 Development of HOM Damped Copper Cavity for the ESRF impedance, simulation, damping, LEP 1244
 
  • N. Guillotin, J. Jacob, V. Serriere
    ESRF, Grenoble
  At the ESRF, HOM driven longitudinal coupled bunch instabilities are currently avoided up to the nominal beam current of 200 mA by precisely controlling the cavity temperatures and thereby the HOM frequencies of the existing five-cell copper cavities. A bunch-by-bunch feedback is presently being commissioned in order to increase the maximum stored current. In parallel, normal conducting strongly HOM damped cavities are under study to possibly replace the five-cell cavities. The design is based on a scaling of the single cell EU cavity*: a pillbox geometry with nose cones and three attached ridged waveguides loaded by ferrites for effective HOM damping. We report on the electromagnetic simulation making use of the 3D codes HFSS and GdfidL. They allowed optimizing the shape of both cavity and dampers, including electromagnetic absorbing material with frequency dependent parameters.

*E. Weihreter et al. A Ridged Circular Waveguide Ferrite Load for Cavity HOM Damping, this conference.

 
 
TUPCH171 Calculation, Measurement and Analysis of Vacuum Pressure Data and Related Bremsstrahlung Levels on Straight Sections of the ESRF vacuum, radiation, storage-ring, optics 1417
 
  • R. Kersevan, P. Berkvens, P. Colomp
    ESRF, Grenoble
  One of the major personal safety issues of modern synchrotron radiation (SR) light sources is the minimization of the exposure of beamline staff and users to high-energy bremsstrahlung (BS) radiation generated in the straight sections of the storage ring and entering the optics hutches of the beamlines. This is particularly important when insertion device (ID) narrow-gap chambers are installed, nowadays characterized by very low specific conductances. At the ESRF, this has led to the implementation of systematic measurements of BS levels and vacuum conditioning curves, in conjunction with the installation of non-evaporable getter (NEG)-coated ID chambers. A dedicated beamline is used to do on-axis measurements of the BS intensity during the initial conditioning period of newly installed NEG-coated ID chambers. This paper will show results of measurements and calculations performed throughout the years, and comment on the suitability from the radiation safety point of view of the installation of NEG-coated chambers in large numbers around the ring.  
 
TUPCH172 Status Report on the Performance of NEG-coated Chambers at the ESRF vacuum, CERN, radiation, beam-losses 1420
 
  • R. Kersevan, M. Hahn, i. Parat
    ESRF, Grenoble
  At the ESRF, the use of NEG-coated narrow gap chambers for insertion device (ID) straight sections has become the standard choice for in-air IDs. A total of 25 chambers have been installed at different times in the ring, with 19 being installed as of Jan 2006, for a total length of 82 m. The vacuum performance has been excellent for all but one of them. It has been found that the now standard "10mm" design, i.e. a 5 m-long, 57x8 mm2 ellipse, is compatible with the multi-bunch operation at 200 mA. Runs at higher currents, performed in preparation of current upgrades, have gone smoothly. During 2005, a 3.5 m-long prototype of a chamber suited for installation in the achromat part of the lattice has been installed in the ring. It was characterized by a much smaller cross-section (30x20 mm2, HxV) as compared to a standard chamber (74x33 mm2, HxV), and by the absence of three lumped pumps, replaced by the NEG-coating. The data taken during a full run have been extremely encouraging, to the point of considering the adoption of a similar design for a future upgrade of the storage ring lattice and vacuum system. A status report will be given, alongside with a discussion of future plans.  
 
WEXPA02 New Developments on RF Power Sources klystron, storage-ring, DIAMOND, linac 1842
 
  • J. Jacob
    ESRF, Grenoble
  The classical generation of RF power with klystrons and tetrodes is evolving and changing to meet the demands of higher efficiency and simpler maintenance. Developments of IOT tubes for FEL, Energy Recovery Linacs and Storage Rings, together with solid state technology approaches and combination techniques for high power generation are opening new alternatives to the classical ones. An overview of the new concepts, designs and solutions applied to the new accelerators will be presented. Advantages and drawbacks of new versus classical technologies as well as strategies for the selection will be discussed.  
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WEPCH011 Optimisation of a New Lattice for the ESRF Storage Ring optics, resonance, quadrupole, lattice 1942
 
  • A. Ropert, L. Farvacque
    ESRF, Grenoble
  The installation of canted undulators in some of the straight sections of the ESRF storage ring is envisaged in the future. In order to free maximum space in the straight sections and minimise the reduction in length of the undulators, a new lattice, in which the straight section quadrupole triplets are replaced by doublets, is being studied. The paper describes the main features of the lattice and presents the experimental results achieved so far.  
 
WEPCH109 Comprehensive Benchmark of Electromagnetic 3D Codes in Time and Frequency Domain impedance, simulation, damping, vacuum 2167
 
  • V. Serriere, N. Guillotin, J. Jacob
    ESRF, Grenoble
  • F. Marhauser, E. Weihreter
    BESSY GmbH, Berlin
  A comprehensive benchmark of todays most powerful numerical 3D Eigenmode and Time Domain Solvers has been performed using the input geometry of a HOM-damped cavity and a highly lossy waveguide load developed at BESSY. The paper details the simulations results together with existing experimental data.  
 
THPCH108 Status of SOLEIL Control Systems controls, SOLEIL, storage-ring, booster 3053
 
  • A. Buteau, P. Betinelli, L.S. Nadolski
    SOLEIL, Gif-sur-Yvette
  The SOLEIL light source is a 2.75 GeV third generation synchrotron radiation facility under construction near Paris Storage ring commissioning is scheduled for April 2006 and 10 BL operation for the end of 2006. This paper will describe the technical solution choosen for the control systems of accelerators and beamlines, and will give the status of the deployment. On the hardware side, the SOLEIL Controls team has implemented an industrial approach using PLCs, standard Motion Controlers and CPCI Systems. The details of our technical choices and architectures will be described in this paper. On the software side, the SOLEIL Controls team has worked closely with ESRF's one on the TANGO framework since 2002. A quick tour on the TANGO software components used for SOLEIL Controls will be detailed. On the supervision layer, SOLEIL has choosen Java as the core technology, using javabeans components provided by the TANGO toolkit within an industrial SCADA (GlobalScreen). These tools and components for Graphical User Interface development will be presented. At last, an overview of the deployment of these systems on our installation will conclude this document.  
 
THPLS011 Operation and Recent Development at the ESRF feedback, undulator, insertion, insertion-device 3290
 
  • J.-L. Revol, J.C. Biasci, J-F. B. Bouteille, J. Chavanne, P. Elleaume, L. Farvacque, L. Hardy, J. Jacob, G.A. Naylor, E. Plouviez, A. Ropert, K.B. Scheidt
    ESRF, Grenoble
  We report on the achieved performance of the ESRF storage ring as well as developments accomplished or underway. A new hybrid filling mode based on groups of bunches and a 4-bunch filling pattern are now delivered to the users. Following the increasing demand of users for beam stability, the fast orbit feedback has been upgraded. The installation of 5 m-long, 8 mm vertical aperture NEG coated aluminum chambers is progressing at a rate of one chamber per shutdown. The increase in current from 200 to 300 mA is being prepared; however, operation in this mode is still impaired by HOM driven longitudinal instabilities. To overcome this difficulty, a longitudinal feedback is being commissioned. HOM damped cavities are also under study to possibly replace the existing five-cell cavities. The policy of preventive maintenance has been continued. However, in 2005 the machine availability was affected by water leaks occurring on front-end absorbers and on one dipole crotch absorber. The crotch absorbers suffer all from the same erosion process that could be delayed by a systematic vertical realignment, leaving time for procurement and replacement of the entire pool.  
 
THPLS119 Development of a Cryogenic Permanent Magnet In-vacuum Undulator at the ESRF undulator, cryogenics, vacuum, permanent-magnet 3559
 
  • C.A. Kitegi, J. Chavanne, D. Cognie, P. Elleaume, C. Penel, B. Plan, F. Revol, M. Rossat
    ESRF, Grenoble
  Lowering the temperature of NdFeB materials increases their field remanence and intrinsic coercivity*. This property is potentially interesting for the construction of cryogenic permanent in-vacuum undulators (CPMU)**. Around 150K, the coercivity is increased to such an extent that the NdFeB material is comparable to the Sm2Co17 as far as resistance to radiation damages is concerned. The improvement in field remanence is less remarkable (15% at 150K) and is dominated by a reversible Spin Reorientation Transition (SRT) occurring around 135K. Below this temperature, the remanence decreases. The complete magnetization curves of NdFeB material measured at different cryogenic temperatures are presented. Non-linear models have been constructed and used in the RADIA code in order to compute the field performance of a hybrid NdFeB in-vacuum undulator. A prototype CPMU is presently under construction at the ESRF. It has a period of 18mm and a magnetic length of 2m. The field integral and local field measurements of the cryogenic device require new systems operated in vacuum. A stretched wire bench and a hall probe bench are under construction; their main characteristics will be presented.

*D. Givord et al. Analysis of hysteresis loops in NdFeB sintered magnets, J. Appl. Phys. 60(9) (3263-3265).**T. Hara et al. Cryogenic permanent undulator, Phys.rev. ST AB volume 7 050702 (2004).