Author: Nadji, A.
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MOPOW050 Study of Lower Horizontal Emittance Optics in the Present Soleil Storage Ring 827
  • H.C. Chao, P. Brunelle, A. Nadji, L.S. Nadolski, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  With the aim of delivering a lower horizontal emittance beam to the users of the present SOLEIL ring, a systematic lattice study is carried out. The goal is to discover feasible optics solutions having the horizontal emittance notably lower than the present value of 3.9 nm rad, while fulfilling all the physical requirements and without changing the current magnet structure in the lattice. The strategy adopted is a cell-wise optimization of the linear lattices in the two types of double-bend cells that constitute the SOLEIL ring. In the second step they are concatenated via finer matching. A global scan of the 5 quadrupole families for the search of stable solutions is performed. The statistical properties are given. One can easily select possible solutions without matching. For the second type of cell having 10 quadrupole families, another scan of quadrupoles and a matching using a quadrupole triplet are applied for linear optics characteristics. Finally, the nonlinear optimization is performed with modern nonlinear optimization algorithms.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW050  
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WEPOW003 Design Considerations of a 7BA-6BA Lattice for the Future Upgrade of SOLEIL 2815
  • R. Nagaoka, P. Brunelle, H.C. Chao, F.J. Cullinan, X.N. Gavaldà, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux
    SOLEIL, Gif-sur-Yvette, France
  Previous studies indicated that adoption of a combination of 7 and 6BA cells in the existing SOLEIL ring enables reaching the target range of the horizontal emittance below 200 pm·rad as expected, in contrast to fewer dipole solutions such as a combination of 5 and 4BA studied earlier (IPAC 2014). However, the previous 7BA-6BA lattice resulted in having unacceptably strong gradients in quadrupoles and dipoles leading to high natural chromaticities. Several schemes that would allow for an improvement are explored, such as shortening the insertion device straight sections by one or two meters to create more space for the magnetic structure, lowering the dipole fields and the use of anti-bends as proposed by A. Streun. The effectiveness of each scheme is evaluated and the best combined use of them for SOLEIL is investigated. Ways to fulfil the constraints of the existing dipole beam lines are studied by introducing longitudinal gradient bends and/or multipole wigglers. The nonlinear optimisation to maximise the on and off-momentum apertures is made by using genetic algorithm-based numerical codes. A comparison of their performance and the obtained results are presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW003  
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