Author: Ghasem, H.
Paper Title Page
MOPAB062 A Single Dipole Source for Broad-Band Soft Photon Beamlines in Diamond-II 261
 
  • M. Apollonio, G. Cinque, H. Ghasem, A.N. Jury, I.P.S. Martin, R. Rambo
    DLS, Harwell, United Kingdom
 
  Diamond-II is a project based at Diamond Light Source for an upgrade towards a Storage Ring characterized by a reduction of a factor 20 in its natural emittance and a doubling of the number of straight sections. At Diamond-II the majority of existing beamline capacity should be maintained, while enhancing their performance thanks to the increase in brightness at the source points. The substantial modification of the lattice imposes a likewise re-design of the broad-band sources, presently based on standard dipoles. In this paper we discuss a possible solution for the IR/THz beamline B22 operating within a photon energy range between 1meV and 1eV. This proposal, ideal for low critical energy and single source point sources, entails the insertion of a dipole in one of the newly created mid-cell straights of the machine, while reducing the bending power of the nearby gradient dipoles. After performing the linear matching of the lattice, reproducing a comparable phase advance in the modified cell, we studied the non-linear dynamics of the system. Comparison of the main observables (Dynamic Aperture, Injection Efficiency and Lifetime) with the baseline case is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB062  
About • paper received ※ 18 May 2021       paper accepted ※ 28 May 2021       issue date ※ 12 August 2021  
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MOPAB063 Commissioning Strategy for Diamond-II 265
 
  • M. Apollonio, R.T. Fielder, H. Ghasem, I.P.S. Martin
    DLS, Oxfordshire, United Kingdom
 
  At Diamond Light Source we are working on the upgrade towards a machine aimed at a factor 20 reduction in emittance and an increase of the capacity for beamlines. Crucially the success of the programme depends on the ability to inject and capture the electrons in the storage ring, and finally reach control of beam alignment and the linear optics. The paper presents the series of strategies adopted to achieve the commissioning of the machine, from the threading procedure ensuring the first turn of the electron beam, to the orbit corrections in the storage ring. Beam based alignment of the quadrupoles and skew quadrupoles is illustrated and restoration of the linear optics (LOCO) for the storage ring is presented. Main performance parameters (Dynamic Apertures, Injection Efficiency and Lifetime) are calculated to evaluate the performance of the commissioned lattices.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB063  
About • paper received ※ 18 May 2021       paper accepted ※ 28 May 2021       issue date ※ 14 August 2021  
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THPAB090 Progress with the Diamond-II Storage Ring Lattice 3973
 
  • H. Ghasem, I.P.S. Martin, B. Singh
    DLS, Oxfordshire, United Kingdom
 
  Building on the CDR proposal for the Diamond-II storage ring, a number of changes have been implemented to improve the performance of the lattice. Firstly, anti-bend magnets have been utilized to provide additional control over the dispersion function, and an improved symmetrization in the phase advance between the sextupoles was found to be beneficial for the dynamic aperture. Furthermore, the longitudinal variable bends have been tailored to reduce the emittance and have had transverse gradient added to improve the optics control in the mid-straights. In the absence of IDs, the current design provides 161 pm electron beam emittance, reducing to 139 pm once all effects are taken into account. The dynamic aperture is large enough to support an off-axis injection scheme using a nonlinear kicker and has a lifetime greater than 4 h. In this paper, the main parameters and magnet specifications for the Diamond-II lattice are provided. The related linear and non-linear beam dynamics issues are discussed, along with the impact of IDs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB090  
About • paper received ※ 19 May 2021       paper accepted ※ 17 June 2021       issue date ※ 26 August 2021  
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