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Rehm, G.

Paper Title Page
TUZM01 Recent Development of Diagnostics on 3rd Generation Light Sources 1016
 
  • G. Rehm
    Diamond, Oxfordshire
 
  A Review of the most performing diagnostics on 3rd generation light sources will be given. Starting with the target performance specification of recent 3rd generation light sources, the demands for diagnostics will be highlighted. Topics include beam position monitors and their integration, emittance measurement by imaging of the stored beam or interference methods and diagnostic requirements for top-up operation. A survey on recent developments and the achieved performances at different accelerators will be presented.  
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TUPC007 Numerical and Experimental Investigation of the Contamination of X-ray Beam Position Monitors by Bending Magnet Edge Radiation 1053
 
  • C. Bloomer, G. Rehm, C. A. Thomas
    Diamond, Oxfordshire
 
  The details of an investigation into bending magnet edge radiation at Diamond are discussed, reviewing the effects of this radiation on X-ray Beam Position Monitoring (XBPM) equipment. For some time it has been recognized that there are difficulties using XBPMs for determining the centre of mass position of an undulator beam due to contamination from bending magnet radiation. While the geometry of the XBPM blades is designed to help reduce background dipole interference, this radiation is known to account for approximately 1% of the signal received, skewing the calculated beam position by several micrometres. We made detailed models of the bending magnet edge radiation using the SRW program and used Matlab to analyse the data. We present this model and compare our prediction to experimental results obtained at Diamond.  
TUPC086 Pinhole Camera Resolution and Emittance Measurement 1254
 
  • C. A. Thomas, G. Rehm
    Diamond, Oxfordshire
 
  Third generation synchrotron light source are characterised by a low emittance and a low emittance coupling. Some light sources are already proposing to operate with extremely low coupling close to 0.1% and thus vertical emittance approaching 1pm. We derive the limits for the emittance coupling measurement due to the resolution of the X-ray pinhole camera. We also show that it is possible to design a pinhole camera in order to push the limit resolution beyond 0.1% emittance coupling. We then illustrate our calculations with the example of Diamond and compare them with experimental data.  
TUPP020 Analysis of Collective Effects at the Diamond Storage Ring 1574
 
  • R. Bartolini, C. Christou, R. T. Fielder, M. Jensen, A. F.D. Morgan, S. A. Pande, G. Rehm, C. A. Thomas
    Diamond, Oxfordshire
 
  The Diamond storage ring has achieved its nominal operating current of 300 mA in multi-bunch mode and up to 10 mA in single bunch mode. Several collective instabilities have been observed and their dependence on machine parameters such as chromaticities, RF voltage and fill pattern have been investigated. We report here the analysis of the observed current thresholds and rise times of the instabilities compared with analytical estimates and tracking simulations. We also present the results of the MAFIA simulations performed with the aim of understanding the main contribution to the impedance of the ring and establishing a machine impedance database.  
WEPC057 Preparation for Top-up Operation at Diamond 2121
 
  • R. P. Walker, P. T. Bonner, F. Burge, Y. S. Chernousko, C. Christou, J. A. Dobbing, M. T. Heron, V. C. Kempson, I. P.S. Martin, G. Rehm, R. J. Rushton, S. J. Singleton, M. C. Wilson
    Diamond, Oxfordshire
  • R. Bartolini
    JAI, Oxford
 
  We report on progress towards top-up operation of Diamond. We describe the extensive safety assessment that has carried out, including the measurements and simulations to assess the potential radiation doses in the case of poor injection efficiency or a top-up "accident", and the various levels of safety measures - procedures, software limits and personnel safety system interlocks - that have been implemented. We describe the top-up control algorithm, the technique used to maintain a given arbitrary filling pattern and the performance in practise. The work carried out to reduce the effect of the injection kickers on the stored beam is described, and the effect of the residual disturbance on user operation is discussed. The modifications to the timing system to provide hardware and software gating signals, and experience with the use of these, are also described.  
THPC053 Turn-by-turn Data Analysis at the Diamond Storage Ring 3101
 
  • R. Bartolini, I. P.S. Martin, G. Rehm, J. Rowland
    Diamond, Oxfordshire
 
  The Diamond Storage Ring has been recently equipped with a set of two pinger magnets that can excite betatron oscillations to large amplitudes in both planes of motion. In conjunction with the turn-by-turn capabilities available at all BPMs, the system provides a powerful diagnostic tools for the characterisation of the linear and non-linear beam dynamics of the electron beam in the storage ring. We report the first results on the application of the Frequency Map Analysis and the measurement of the resonant driving terms at the Diamond Storage Ring.  
THPC118 Performance and Future Developments of the Diamond Fast Orbit Feedback System 3257
 
  • M. T. Heron, M. G. Abbott, J. A. Dobbing, G. Rehm, J. Rowland, I. Uzun
    Diamond, Oxfordshire
  • S. Duncan
    University of Oxford, Oxford
 
  The electron beam in the Diamond Synchrotron Light Source is stabilised in two planes using a Global Beam Orbit Feedback system. This feedback system takes the beam position from 168 Libera electron beam position monitors, for both planes, and calculates offsets to 336 corrector power supplies at a rate ~10kHz. The design and implementation will be summarised, and system performance and first operational experience presented. Current and potential future developments of the system will be considered.  
THPC126 Performance and Features of the Diamond TMBF System 3281
 
  • A. F.D. Morgan, G. Rehm, I. Uzun
    Diamond, Oxfordshire
 
  The Diamond Transverse Multibunch Feedback System (TMBF) comprises an in-house designed and built analogue frontend to select and condition the position signals for each bunch. This is combined with the Libera Bunch-by-Bunch system to digitise the signal and perform the relevant calculations before driving the output stripline kickers. As the electronics are based on an FPGA this has allowed us to implement several features in addition to the basic feedback calculations. We report on improvements to both the analogue and digital parts of the TMBF system, along with recent achievements in using the system for instability mode stabilisation and for tune measurement. Also we discuss the potential of the system and additional functionality we plan on introducing in the near future.