Author: Singh, B.
Paper Title Page
MOPOTK037 Impact of Insertion Devices on Diamond-II Lattice 539
 
  • B. Singh, R.T. Fielder, H. Ghasem, J. Kallestrup, I.P.S. Martin, T. Olsson
    DLS, Oxfordshire, United Kingdom
 
  Funding: DLS ltd
The DIAMOND-II lattice is based on the ESRF-EBS cell, with the centre dipole replaced by a (chromatic) mid-straight, and a -I transformer, higher order achromat (HOA) & dispersion bumps to control the nonlinear dynamics. The majority of insertion devices currently on operation in Diamond will be either retained or upgraded as part of the Diamond-II program, and the new mid straights allow the total number of ID beamlines to be increased from 28 to 36.Therefore, it is important to investigate how IDs will affect the emittance, energy spread and linear and nonlinear beam dynamics. The kickmap approach has been used to model all IDs, including APPLE-II and APPLE-II Knot with active shim wires. In this paper, the outcome of these investigations will be presented and discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK037  
About • Received ※ 04 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 07 July 2022  
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TUPOMS033 Diamond-II Storage Ring Developments and Performance Studies 1491
 
  • I.P.S. Martin, H.C. Chao, R.T. Fielder, H. Ghasem, J. Kallestrup, T. Olsson, B. Singh, S.W. Wang
    DLS, Oxfordshire, United Kingdom
 
  The Diamond-II project includes a replacement of the existing double-bend achromat storage ring with a modified hybrid 6-bend achromat, doubling the number of straight sections and increasing the photon beam brightness by up to two orders of magnitude*. The design and performance characterisation of the new storage ring has continued to progress, including a switch to an aperture-sharing injection scheme, freezing the magnet layout, studying the impact of IDs, developing a commissioning procedure and investigating collective effects. In this paper we present an overview of these studies, including final performance estimates.
*Diamond-II Technical Design Report, Diamond Light Source Ltd.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS033  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 27 June 2022
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TUPOMS034 Tunability and Alternative Optics for the Diamond-II Storage Ring 1495
 
  • H. Ghasem, I.P.S. Martin, B. Singh
    DLS, Oxfordshire, United Kingdom
 
  When defining the magnet specifications, a key consideration is that the hardware should be flexible enough to allow some contingency for future tuning requirements or for alternative lattice solutions to be implemented. To define the required tunability of the magnets, we have investigated two lattice solutions for the Diamond-II storage ring upgrade, one with reduced beta functions at the straight sections for improved matching to the photon beam and one with an ultra-low emittance of 87 pm with IDs. In this paper, the linear and nonlinear beam dynamic issues as well as the photon beam brightness for these two options will be presented and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS034  
About • Received ※ 06 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 25 June 2022
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TUPOMS035 Emittance Feedback for the Diamond-II Storage Ring Using Resonant Excitation 1498
 
  • S. Preston, T. Olsson, B. Singh
    DLS, Oxfordshire, United Kingdom
 
  In the Diamond Light Source storage ring, the vertical emittance is kept at 8 pm rad during operation to maintain the source brightness for the users. This is achieved by a feedback which modifies the skew quadrupole strengths, but has disadvantages such as the introduction of betatron coupling and vertical dispersion. For the proposed Diamond-II upgrade, the storage ring will have a much smaller horizontal emittance, meaning a significantly larger coupling would be required to reach the target vertical emittance, negatively affecting the off-axis injection process. To solve this problem, a feedback using the transverse multibunch feedback striplines to drive the beam at a synchrotron sideband is planned. By driving the beam resonantly in this way, the emittance can be increased without modification of the optics. This paper describes simulations of the effects of linear and non-linear optics on the excitation as well as the impact of the machine impedance for the Diamond-II storage ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS035  
About • Received ※ 19 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022  
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THPOPT016 Commissioning Simulations for the DIAMOND-II Upgrade 2598
 
  • H.C. Chao, R.T. Fielder, J. Kallestrup, I.P.S. Martin, B. Singh
    DLS, Oxfordshire, United Kingdom
 
  The Diamond-II storage ring, compared to Diamond, improves the natural beam emittance from 2.7 nm to 160 pm and the beam energy from 3 to 3.5 GeV. The number of straight sections is also doubled from 24 to 48 thanks to the modified hybrid six-bend-achromat lattice. To reduce the impact on the existing science program, the dark time period must be minimised. To assist in this aim, storage ring commissioning simulations have been carried out to predict and resolve possible issues. These studies include beam commissioning starting from on-axis first-turn beam threading up to beam based alignment and full linear optics correction with stored beam. The linear optics corrections with insertion devices are also included. The machine characterisations at different stages are compared. Considerations on realistic chamber limitations, error definitions and some commissioning strategies are also discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT016  
About • Received ※ 19 May 2022 — Accepted ※ 15 June 2022 — Issue date ※ 15 June 2022  
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THPOPT048 Impact of IDs on the Diamond Storage Ring and Application to Diamond-II 2705
 
  • R.T. Fielder, B. Singh
    DLS, Oxfordshire, United Kingdom
 
  When investigating the effect of insertion devices (IDs) on storage ring operations, it is not possible to simulate all of the large number of gap, phase and field settings that are available. This can be of particular concern for transient effects in IDs that are moved frequently, or APPLE-II devices which may use many different polarisation states. We therefore present measurements of the impact of selected IDs on various parameters in the current Diamond storage ring including orbit distortion, tunes, chromaticity and emittance, and assess the expected impact when applied to the Diamond-II lattice.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT048  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022
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THPOPT049 Beam Dynamics Studies for the Diamond-II Injector 2708
 
  • I.P.S. Martin, R.T. Fielder, J. Kallestrup, T. Olsson, B. Singh
    DLS, Oxfordshire, United Kingdom
  • J.K. Jones, B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  The replacement, low-emittance booster for the Diamond-II project will have a racetrack structure of 36 units cells constructed from alternating focussing and defocussing combined-function dipoles*. In this paper we report on how the design and performance characterisation of the booster has recently developed; this includes an increase in the injection energy from 100 to 150 MeV, a modified circumference to match to the storage ring RF frequency, and a new nominal tune-point to improve the performance and enable emittance exchange. The influence of the vacuum chamber impedance and intra-beam scattering on the electron bunch parameters during the ramp are presented, along with the necessary changes to the transfer line layouts.
*I.P.S. Martin, et al. "Progress with the Booster Design for the Diamond-II Upgrade", in Proc. IPAC’21, paper ID MOPAB071, Campinas, Brazil, May 2021
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT049  
About • Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 29 June 2022
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