Author: Bartolini, R.
Paper Title Page
MOPRO099 Long-term Stability of the Diamond Light Source Storage Ring 319
 
  • M. Apollonio, K.A.R. Baker, R. Bartolini, W.J. Hoffman, J. Kay, V.C. Kempson, I.P.S. Martin
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
 
  The Diamond Storage Ring (SR) has been in operation since January 2007. This paper summarises a number of measurements that have been made over that period to monitor the SR stability in height and position including general survey, Hydrostatic Levelling System (HLS), horizontal and vertical magnet corrector strengths as well as Radio Frequency (RF) measurements that have given an indication of changing circumference.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO099  
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MOPRO100 Engineering Integration Constraints on the Beam Physics Optimisation of the DDBA Lattice for Diamond 322
 
  • R. Bartolini, M. Apollonio, C.P. Bailey, M.P. Cox, N.P. Hammond, R. Holdsworth, J. Kay, I.P.S. Martin, V.V. Smaluk, R.P. Walker
    DLS, Oxfordshire, United Kingdom
  • T. Pulampong
    JAI, Oxford, United Kingdom
 
  The design and optimisation of the new DDBA lattice for Diamond has been performed taking fully into account, from the early stages, the geometry and the engineering integration constraints. In this paper we review the evolution of the DDBA cell, the rationale for its modification and the optimisation strategy used.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO100  
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MOPRO101 Transparent Re-alignment of the Diamond Storage Ring 325
 
  • M. Apollonio, R. Bartolini, W.J. Hoffman, E.C. Longhi, A.J. Rose, A. Thomson
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
 
  72 out of the 74 girders on which the Diamond Storage Ring magnets are mounted, can in principle be moved along 5 degrees of freedom (sway, heave, yaw,pitch, roll) potentially allowing a thorough re-alignment of the machine. Previously conducted tests improved our knowledge of the system both in terms of simulations and comprehension of the control system we rely upon. In this report we present the results of more detailed tests which now give us full confidence in our ability to predict the results of any given set of girder moves. We also discuss possible ways of increasing the speed of the procedure, and a strategy to mitigate the impact of girder moves involving nearby beam lines.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO101  
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MOPRO103 The Double-double Bend Achromat (DDBA) Lattice Modification for the Diamond Storage Ring 331
 
  • R.P. Walker, M. Apollonio, C.P. Bailey, R. Bartolini, M.P. Cox, R.T. Fielder, N.P. Hammond, M.T. Heron, J. Kay, I.P.S. Martin, S.P. Mhaskar, G. Rehm, E.C.M. Rial, B. Singh, V.V. Smaluk, A. Thomson
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini, T. Pulampong
    JAI, Oxford, United Kingdom
 
  The concept of converting individual cells of the Diamond Double Bend Achromat (DBA) lattice into a modified 4-bend achromat with a new straight section for insertion devices (IDs) in the middle of the arc, grew out of earlier studies of low emittance MBA lattices*, and was motivated by the need for additional ID straight sections, since all of the 22 ID straight sections in the Diamond storage ring are either occupied or have been allocated to future beamlines. Such a modification effectively replaces each DBA cell with two new DBA cells, hence the term Double-DBA or DDBA has come to be used for the project. Since the tangent point for bending magnet beamlines lies close to the start of the second dipole in the original DBA, this allows unused exit ports and spaces on the experimental hall which are available for future bending magnet beamlines to be used for higher performance ID beamlines. In this report we present an overview of the status of the project, the various accelerator physics and engineering studies that have been carried out, and plans for the implementation of one or two DDBA cells in Diamond.
* R. Bartolini, IPAC'13, p. 237
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO103  
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TUPRO114 Magnet Design for the Diamond DDBA Lattice Upgrade 1319
 
  • R. Bartolini, C.P. Bailey, N.P. Hammond, R. Holdsworth, J. Kay, S.P. Mhaskar, E.C.M. Rial, R.P. Walker
    DLS, Oxfordshire, United Kingdom
  • T. Pulampong
    JAI, Oxford, United Kingdom
 
  The DDBA lattice upgrade for Diamond presents challenging requirements on the magnet system in order to satisfy the tight constraints on the beam optics. Advanced, combined function gradient dipoles and high gradient quadrupoles are needed. We present the tolerance specification, the design solutions and the measurement and alignment strategies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO114  
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TUPRI082 Active Optics Stabilisation Measures at the Diamond Storage Ring 1760
 
  • I.P.S. Martin, R. Bartolini, R.T. Fielder, M.J. Furseman, E.C. Longhi, G. Rehm, W.A.H. Rogers, A.J. Rose, B. Singh
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
 
  The Diamond storage ring is currently operated with 26 insertion devices (IDs), including 14 in-vacuum IDs, 7 APPLE-II type helical undulators and 2 superconducting wigglers. Differences in the design, construction and operation of these devices, combined with different Twiss parameters at the source point, mean each has a different impact on tune stability and beta-beat. In turn, these parameters affect the on and off-momentum dynamic aperture and ultimately impact on the injection efficiency and lifetime. Another source of optics variation arises from the coherent tune shift with current, which when injecting from zero current causes the tune to span the available good-tune region. In this paper we discuss the difficulties of operating the Diamond storage ring in top-up mode with these effects, and present the various measures taken to stabilise the storage ring optics.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI082  
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TUPRI083 A Fast Optics Correction for the Diamond Storage Ring 1763
 
  • I.P.S. Martin, M.G. Abbott, R. Bartolini, M.J. Furseman, G. Rehm
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
 
  Since March 2013, the Diamond storage ring has been operated with a target vertical emittance of 8 pm.rad. This condition is achieved by first applying a LOCO* optics correction with IDs set to their typical gaps, then offsetting the skew quadrupole magnets in order to increase the vertical emittance again to the desired value. Whilst a feedback application** is able to stabilise the vertical emittance during ID gap and phase changes in the short to medium term, regular applications of LOCO are still required to maintain good coupling control in the longer term. In this paper we describe measures taken to speed up the optics correction procedure, including a fast orbit response matrix measurement, a reduction of the number of magnets used to measure the data, and a distribution of the LOCO calculations to run in parallel.
* J. Safranek, Nucl. Inst. Meth. A, 338, (1997)
** I.P.S. Martin, et al., IPAC 2013, MOPEA071, www. JACoW.org
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI083  
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THPRO031 Short Pulses THz FEL for the Oxford Accelerator Science Laboratory 2934
 
  • T. Chanwattana, R. Bartolini, A. Seryi
    JAI, Oxford, United Kingdom
  • R. Bartolini
    DLS, Oxfordshire, United Kingdom
  • E. Tsesmelis
    CERN, Geneva, Switzerland
 
  The Accelerator Science Laboratory (ASL) is under development at the John Adams Institute in Oxford with the aim of fostering advanced accelerator concepts and applications. The option to install a short pulse THz FEL based on a conventional RF accelerator driven by a RF photocathode gun is being investigated. This report presents the concept of the facility, the accelerator physics and FEL studies and engineering integration in the University physics department.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO031  
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THPRO032 Studies on LPWA-based Light Sources driven by a Transverse Gradient Undulator 2937
SUSPSNE008   use link to see paper's listing under its alternate paper code  
 
  • T. Chanwattana, R. Bartolini, A. Seryi
    JAI, Oxford, United Kingdom
  • R. Bartolini
    DLS, Oxfordshire, United Kingdom
 
  The Accelerator Science Laboratory (ASL) is under development at the John Adams Institute in Oxford with the aim of fostering advanced accelerator concepts and applications. The option to install a LPWA based light source driven by a transverse gradient undulator is being investigated. This report presents the accelerator physics, FEL studies and the performance expected from such a facility.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO032  
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THPME183 Longitudinal Beam Profile Measurements of the Microbunching Instability 3706
SUSPSNE075   use link to see paper's listing under its alternate paper code  
 
  • W. Shields, A. Finn, P. Karataev
    JAI, Egham, Surrey, United Kingdom
  • R. Bartolini, I.P.S. Martin, G. Rehm
    DLS, Oxfordshire, United Kingdom
 
  The microbunching instability is a phenomenon characterized by the onset of radiation bursts above a threshold bunch current. These bursts consist of coherent emissions with wavelengths comparable to the bunch length and shorter. The instability has recently been observed at Diamond Light Source, a 3rd generation synchrotron. The operating conditions for triggering the instability at Diamond Light Source are well known, however measuring the spectral content of the resulting emissions is a more challenging investigation. A Michelson interferometer has been installed with the aim of recording the coherent spectrum from the bunches, using ultra-fast response Schottky Barrier Diode detectors. The longitudinal profile of the bunches can be estimated with subsequent analysis.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME183  
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