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IT03 Beam Loss Monitors at the ESRF beam-losses, vacuum, radiation, injection 3
 
  • B. Joly, U. Weinrich, G.A. Naylor
    ESRF, The European Synchrotron Radiation Facility, Grenoble, France
  The European Synchrotron radiation facility is a third generation x-ray source providing x-rays on a continuous basis. As a facility available to external users, the monitoring of radiation caused by the loss of high-energy stored beam is of great concern. A network of beam loss monitors has been installed inside the storage ring tunnel so as to detect and localize the slow loss of electrons during a beam decay. This diagnostic tool allows optimization of beam parameters and physical aperture limits as well as giving useful information on the machine to allow the lifetime to be optimized and defects localized.  
 
IT08 Controls and Beam Diagnostics for Therapy-Accelerators ion, diagnostics, controls, light-ion 24
 
  • H. Eickhoff
    GSI, Gesellschaft für Schwerionenforschung, Darmstadt, Germany
  During the last four years GSI has developed a new procedure for cancer treatment by means of the intensity controlled rasterscan-method. This method includes active variations of beam parameters during the treatment session and the integration of 'on-line' PET monitoring. Starting in 1997 several patients have been successfully treated within this GSI experimental cancer treatment program; within this program about 350 patients shall be treated in the next 5 years. The developments and experiences of this program accompanied by intensive discussions with the medical community led to a proposal for a hospital based light ion accelerator facility for the clinic in Heidelberg. An essential part for patients treatments is the measurement of the beam properties within acceptance and constancy tests and especially for the rasterscan method during the treatment sessions. The presented description of the accelerator controls and beam diagnostic devices mainly covers the requests for the active scanning method, which are partly more crucial than for the passive scattering methods.  
 
CT04 Bunch Length Measurements in LEP pick-up, impedance, photon, monitoring 59
 
  • A.J. Burns, H. Schmickler
    CERN, Geneva, Switzerland
  For many years a streak camera has been used for observing the longitudinal distribution of the particles in any LEP e+ or e- bunch (5-50 ps r.m.s. length) on a turn by turn basis, using synchrotron light. In 1996, a comparison made with the longitudinal vertex distributions of 3 LEP experiments allowed the identification and elimination of certain systematic errors in the streak camera measurements. In 1997, a new bunch length measurement technique was commissioned that uses the high frequency slope of the bunch power spectrum from a button pickup. In 1998, this new method was confronted with measurements from the streak camera and the LEP experiments. The measurements made in 1996 and 1998 are presented, with emphasis on the calibration of the two instrumental methods and their respective precision and limitations.  
 
CT06 Developments and Plans for Diagnostics on the ISIS Synchrotron injection, diagnostics, betatron, resonance 67
 
  • C.M. Warsop, D.J. Adams, K. Tilley
    RAL, Rutherford Appleton Laboratory
  Developments of diagnostics on the 800 MeV High Intensity Proton Synchrotron of ISIS, the Spallation Neutron Source at the Rutherford Appleton Laboratory in the UK, are described. Recent upgrades to instrumentation and control computers have made much more information readily available, which is valuable for control of a loss limited, high intensity machine. Measurements on high intensity beams have fundamental limitations in terms of accuracy, detail and interpretation. However, it is found that use of specially configured low intensity diagnostic beams can provide much detailed information not otherwise available, which is extremely valuable after careful interpretation. The methods and systems being developed to help trouble shooting, to find optimal conditions rapidly and systematically, and to improve understanding of high intensity performance are described.  
 
CT07 The ELETTRA Streak Camera: System Set-Up and First Results electron, single-bunch, storage-ring, cathode 72
 
  • M. Ferianis
    ELETTRA, Sincrotrone Trieste, Trieste, Italy
  At ELETTRA, a Streak Camera system has been installed and tested. The bunch length is a significant machine parameter to measure, as it allows a direct derivation of fundamental machine characteristics, like its broadband impedance. At ELETTRA the Light from a Storage Ring Dipole is delivered through an optical system to an Optical Laboratory where it can be observed and analysed. The Streak Camera is equipped with different timebases, allowing both single sweep and dual sweep operation modes, including the Synchroscan mode. The Synchroscan frequency equal to 250 MHz, which is half of the ELETTRA RF frequency, allows the acquisition of consecutive bunches, 2ns apart. To fully exploit the performances of the Streak Camera, an optical path has been arranged which includes a fast opto-electronic shutter. By doing so, the optical power deposited on the photo-cathode is reduced in the different ELETTRA fillings.  
 
CT08 Adaptive Optics for the LEP 2 Synchrotron Light Monitors extraction, radiation, synchrotron-radiation, optics 77
 
  • G. Burtin, R.J. Colchester, G. Ferioli, J.J. Gras, R. Jung, J.M. Vouillot
    CERN, Geneva, Switzerland
  The image obtained with the LEP synchrotron radiation telescopes deteriorates, giving multiple and deformed images, when the beam energy goes beyond 80 GeV at beam currents above 2 mA. This problem is due to the deformation of the light extracting beryllium mirror, by as little as 1 mm, and had been predicted at the design stage. To overcome this problem, several changes together with an adaptive optics set-up have been introduced. These essentially consist of a cylindrically deformable mirror to compensate the cylindrical deformation of the beryllium mirror and a movable detector to compensate the spherical deformation. Both components are continuously adjusted as a function of beam current and energy.  
 
CT09 Luminosity Optimization in DAΦNE luminosity, coupling, diagnostics, feedback 82
 
  • F. Sannibale
    INFN-LNF, Laboratori Nazionali di Frascati dell'INFN, Frascati, Italy
  DAΦNE the Frascati F-factory, started the two beams commissioning on March 1998. Since then a relevant amount of experience concerning the techniques and procedures for optimizing the luminosity has been acquired. All the schemes used are strongly based on the use of various diagnostic systems including a dedicated luminosity monitor, orbit measurement, tune monitor, synchrotron light monitor and others. A summary of the used techniques, with accent on the diagnostic aspects, is presented.  
 
CT10 Real Time Display of the Vertical Beam Sizes in LEP Using the BEXE X-Ray Detector and Fast VME Based Computers positron, electron, luminosity, radiation 87
 
  • R. Jones, A. Manarin, G. Pignard, E. Rossa, H. Schmickler, M. Sillanoli, C. Surback
    CERN, Geneva, Switzerland
  Fast X-ray detectors based on CdTe photoconductors have been installed in LEP since the beginning of its operation in 1989. The angular divergence of the high energy photons from the synchrotron radiation (x-rays) and the narrow spacing of the 64 photoconductors of the detector allow a good measurement of vertical beam profiles down to an rms beam size of 300 mm. This paper presents some specific parameters and experimental results of an upgrade program in which the local processing power of the front-end electronics has been increased by a factor 50. Such a powerful tool has allowed a real time display of the time evolution of the vertical beam sizes. An online correlation plot between the electron and positron beam sizes (turn by turn) is also displayed. These online video images are available in the LEP control room and are used in daily operation for luminosity optimisation.  
 
PS02 Chromaticity Measurements at HERA-P Using the Head-Tail Technique with Chirp Excitation betatron, proton, pick-up, kicker 103
 
  • M. Wendt, F. Willeke
    DESY, Deutsches Elektronen-Synchrotron, Hamburg, Germany
  • A. Boudsko
    TRIUMF, Vancouver, Canada
  • O.R. Jones, H. Schmickler
    CERN, Geneva, Switzerland
  Experiments have been performed in the HERA proton ring (HERA-p) to test a quasi non-destructive method of chromaticity measurements for protons. The method is based on the detection of the head-tail phase shift of coherend betatron oscillations using a broadband beam position pickup and a commercial “fast-frame” oscilloscope. Previous experiments have relied on a single kick for transverse excitation, whereas the results presented here were carried out using swept frequency “chirp” excitation. The tests proved to be successful, and the method seems to be a good candidate for chromaticity measurement in new large hadron accelerators, such as LHC.  
 
PS04 Influence of transverse beam dimensions on beam position monitor signals pick-up, emittance, quadrupole, instrumentation 106
 
  • A. Jankowiak, T. Weis
    DELTA, Institute for Accelerator Physics and Synchrotron Radiation, University of Dortmund, Germany
  In this paper we will evaluate the influence of transverse beam dimensions on the signal functions of a beam position monitor (BPM) with capacitive pick-up electrodes. The error which occurs in the determination of the beam position when disregarding these effects is calculated as an example for the DELTA1 BPM. The possibility to use this effect for the measurement of the beam size / emittance is discussed.  
 
PS06 Turn-By-Turn Phase Space Diagram Construction for Non-Linear Betatron Oscillation lattice, betatron, pick-up, simulation 112
 
  • A. Kalinin, V. Smaluk
    BINP, Budker Institute of Nuclear Physics, Novosibirsk, Russia
  The problem of phase space diagram construction for non-linear betatron oscillation measured by pickup, is considered. The conventional two-pickup method of phase trajectory construction was improved. Discrete Fourier filter applied to data measured yields a large dividend in accuracy. The result of our investigations is the method of turn-by-turn phase trajectory construction using data measured by single pickup. The single-pickup method developed was tested by computer simulation of non-linear betatron oscillation in several models of magnet lattice. Practicality of the method and its accuracy limitation were studied. The method applying for experimental study of beam dynamic is discussed.  
 
PS09 Beam Steering With Image Processing In The Cryring Injection Beamline quadrupole, injection, ion, focusing 118
 
  • A. Källberg, A. Simonsson
    MSI, Manne Siegbahn Laboratory Of Physics, Stockholm, Sweden
  By varying six quadrupoles and observing how the beam spot moves on three fluorescent screens the beam is aligned in the injection beamline. The method is now automated and upgraded by using image processing of the picture to get the position of the beam.  
 
PT02 Real-time betatron tune measurement in the accelerator ramp at COSY-Jülich betatron, acceleration, diagnostics, feedback 156
 
  • J. Dietrich, I. Mohos
    IKP, Forschungszentrum Jülich GmbH, Jülich, Germany
  A new real-time method for betatron tune measurements at COSY was developed and tested from the early 1997. A bandlimited broadband noise source was used for beam excitation, the transversal beam position oscillation was bunch-synchronous sampled and digitized with a high resolution ADC. The Fourier transform of the acquired data represents immediately the betatron tune. After the first promising experiments an automatic tunemeter was constructed. The tunemeter is used as routine diagnostic tool since end of 1998.  
 
PT03 Measuring beam intensity and lifetime in BESSY II storage-ring, vacuum, injection, microtron 159
 
  • R. Bakker, R. Georgen, P. Kuske, J. Kuszynski
    BESSY, Berliner Speicherring-Gesellschaft für Synchrotronstrahlung mbH, Berlin, Germany
  The measurement of the intensity of the beam in the transfer lines and the storage ring are based on current transformers. The pulsed current in the transfer lines is measured with passive Integrating Beam Current Transformers (ICT). The bunch charge is transferred to a DC-voltage and sampled with a multifunction I/O-board of a PC. The beam current of the storage ring is measured with a high precision Parametric Current Transformer (PCT) and sampled by a high quality digital volt meter (DVM). A stand alone PC is used for synchronisation, real-time data acquisition and signal processing. Current and lifetime data are updated every second and send via CAN- bus to the BESSY II control system. All PC programs are written in LabVIEW.  
 
PT16 Status of the delta synchrotron light-monitoring-system radiation, synchrotron-radiation, shielding, emittance 196
 
  • U. Berges, K. Wille
    DELTA, Institute for Accelerator Physics and Synchrotron Radiation, University of Dortmund, Germany
  A synchrotron radiation source like DELTA needs an optical monitoring system to measure the beam size at different points of the ring with high resolution and accuracy. The measurements with the present synchrotron light monitors show that beam sizes larger than 250 μm can be measured. The measured emittance is of the order of the theoretical values of the optics and goes down to 8 nm rad. The magnification of the system can simply be increased by adding another lens to measure smaller emittances and beamsizes down to 100 μm. In this case you still have an optical image of the beam available, but sometimes the position of the camera has to be adapted due to the great magnification of the optical system. The image processing system which is based on a VME Framegrabber makes a two dimensional gaussian fit to the images from different synchrotron light-monitors. First tests with monochromatic components of the synchrotron radiation (500 nm and 550 nm) and with short time cameras (shutter time down to 1/10000 s) have been performed. A two-dimensional PSD has been installed to measure slow beam motion. To measure small beam sizes, especially in the vertical plane, diffraction elements will be used. This paper gives an overview over the present installation and the results.