Author: Bartolini, R.
Paper Title Page
TUPGW076 Early Commissioning Simulation of the Diamond Storage Ring Upgrade 1577
 
  • H. Ghasem, M. Apollonio, R. Bartolini, J.P. Kennedy, I.P.S. Martin
    DLS, Oxfordshire, United Kingdom
 
  A low beam emittance lattice has been designed for up-grade of the Diamond storage ring. Due to the use of strong focusing elements and rather small vacuum cham-ber and considering the required short dark time, commis-sioning of the designed storage ring becomes very chal-lenging. This paper briefly explains the progress of early commissioning simulations of the storage ring, gives the required engineering tolerances, presents the first simula-tion results and discusses the non-linear beam dynamics (NLBD) issues after successful commissioning with and without insertion devices (IDs).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW076  
About • paper received ※ 13 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW077 Impact of the DIAD Wiggler and ’Missing-sextupole’ Optics on the Diamond Storage Ring 1581
 
  • I.P.S. Martin, R. Bartolini, B. Singh
    DLS, Oxfordshire, United Kingdom
 
  In order to generate space for a short, out-of-vacuum multipole wiggler for the DIAD beamline, a single sextupole was removed from one of the DBA arcs in the Diamond Storage Ring during June 2018. The removal of this sextupole presented a number of challenges to the operation of the storage ring, requiring a re-optimisation of the remaining sextupole strengths*, a change in tune-point and modification of the orbit and coupling correction schemes. In this paper we describe the implementation of these changes, and provide an assessment of the impact that the installed wiggler has made on the storage ring parameters.
* B. Singh et al. ’Studies to Install a Multipole Wiggler by Removing a Chromatic Sextupole in Diamond Storage Ring’, Proc. IPAC 2016, Busan, Korea, paper THPMR050, (2016)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW077  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW078 Harmonic Cavity Design Choice for Lifetime Increase in Diamond-II 1585
 
  • T. Olsson, R. Bartolini, I.P.S. Martin
    DLS, Oxfordshire, United Kingdom
 
  The ongoing trend towards synchrotron light storage rings with ultralow emittance leads to a requirement for strong magnet gradients, which reduce the dynamic aperture and thus the Touschek lifetime of the machine. This is also the case for the planned upgrade of the Diamond Light Source. One option to increase the Touschek lifetime is to lengthen the electron bunches with a harmonic cavity operated close to a harmonic of the fundamental RF frequency. This paper presents studies of a harmonic cavity for Diamond-II with the focus on maximising the lifetime increase. It is foreseen that the ring will have to operate with a gap in the fill pattern to avoid instabilities and therefore multiparticle tracking was used to determine the effect on stability and lifetime for various cavity parameters taking into account transient beam loading.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW078  
About • paper received ※ 14 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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TUPGW079 Exploratory Lattice Design Studies for Diamond-II 1589
 
  • B. Singh, R. Bartolini, J. Bengtsson, H. Ghasem, I.P.S. Martin
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
 
  We pursue Robust Design of a Ring-Based Synchrotron Light Source as a System. In particular, the Design Phi-losophy is based on: ’ To Control the Nonlinear Dynamics: Control the Linear Optics. In particular, by: ’ Optimal Control of Natural Chromaticity. ’ ’-I Transformer’ between Chromatic Sextupoles for Unit Cell. ’ Higher-Order-Achromat for Super Period. In addition, by pushing the Requirements for Robust & Efficient Injection ’Upstream’, i.e., by considering On-Axis Injection, and by utilizing Reverse Bends (to trans-cend the reductionist Theoretical Minimum Emittance Cell), either: ’ the Natural Emittance can be reduced further, ’ or the Touschek Lifetime can be improved. Bottom line, a Design Choice.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW079  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPMP042 Reduction of Stored Beam Oscillations During Injection at Diamond Light Source 2426
 
  • R.T. Fielder, M. Apollonio, R. Bartolini, C. Bloomer, I.P.S. Martin
    DLS, Oxfordshire, United Kingdom
 
  At Diamond injection is performed by means a of a four kicker off-axis system, relying on a perfect timing and amplitude setting to produce a closed bump. Ageing of some of the kicker vessel components has progressively spoiled the performance of the system, causing oscillations in the stored beam. Various schemes to control these oscillations have been considered including introducing an additional compensating kicker, and installing a non-linear injection kicker. Results of simulations analysing these schemes are presented, along with measurements taken in the storage ring using an existing pinger magnet. The effects of the reduction on the quality of beam seen by beamlines is also considered.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP042  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPMP043 Injection Studies for the Proposed Diamond-II Storage Ring 2430
 
  • I.P.S. Martin, R. Bartolini, H. Ghasem, J.P. Kennedy, B. Singh
    DLS, Oxfordshire, United Kingdom
 
  The baseline design for the Diamond-II storage ring consists of a Modified-Hybrid 6-Bend Achromat, combining the ESRF-EBS low-emittance cell design with the DDBA mid-straight concept*,**. This cell design provides sufficient dynamic aperture to permit an off-axis injection scheme, provided the emittance of the injected beam is sufficiently low. In this paper we present simulations of an injection scheme using the anti-septum concept***, along with the design of an upgrade to the existing booster synchrotron. Alternate injection strategies are also discussed.
*ESRF Technical Design Study, ’The Orange Book’, (2014)
**R. Bartolini et al., PRAB 21, 050701, (2018)
***C. Gough, M. Aiba, Proc. IPAC 2017, Copenhagen, Denmark, paper MOPIK104, (2017)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP043  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPGW071 Genetic Optimisation of Beamline Design for DIAMOND 3753
 
  • F. Bakkali Taheri, M. Apollonio, R. Bartolini, B. Singh
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini, J. Li
    JAI, Oxford, United Kingdom
  • R. Bartolini
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
 
  The problem of optimisation of beamline structures is studied, from the point of view of multi-objective genetic algorithms. While this approach has been successfully used in the exploration of potential particle accelerator lattices, it has never been applied to beamline design. In this paper, the Non-Dominated Sorting Genetic Algorithm II (NGSA II) is used to optimize a structure where photons are assumed to propagate through the optical elements according to the wavefront model as implemented in SRW. It is shown that appropriate objective functions can help to set up an interesting set of parameters, with competitive computational resources compared to the traditional approach. Examples illustrating this optimization method are shown in the context of DIAMOND.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW071  
About • paper received ※ 13 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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