Keyword: linear-dynamics
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THPAF065 Semi-Empirical Hamiltonian Model for Elliptical Cavities cavity, linac, simulation, proton 3127
 
  • E. Laface, J. F. Esteban Müller
    ESS, Lund, Sweden
  
  We propose to use the sum of TM0m0 modes to treat a radio-frequency superconducting elliptical cavity as a pill-box cavity with variable radius. The amplitudes of the different modes are obtained interpolating the field-map of the cavity with the model. Once the field is calculated, the Hamiltonian of the cavity is constructed and used to evaluate the transfer matrices associated to each step of the field-map. The multi-particle non-linear dynamics can also be evaluated using the Lie Transform of the Hamiltonian. The results are benchmarked against the ESS Linac Simulator contained in the OpenXAL suite.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF065  
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THPAK088 Matrix Representation of Lie Transform in TensorFlow network, simulation, storage-ring, GPU 3438
 
  • A.N. Ivanov, S.N. Andrianov, N.V. Kulabukhova, A.A. Sholokhova
    St. Petersburg State University, St. Petersburg, Russia
  • E. Krushinevskii, E. Sboeva
    Saint Petersburg State University, Saint Petersburg, Russia
  
  In the article, we propose an implementation of the matrix representation of Lie transform using TensorFlow as a computational engine. TensorFlow allows easy description of deep neural networks and provides automatic code execution on both single CPU/GPU and cluster architectures. In this research, we demonstrate the connection of the matrix Lie transform with polynomial neural networks. The architecture of the neural network is described and realized in code. In terms of beam dynamics, the proposed technique provides a tool for both simulation and analysis of experimental results using modern machine learning techniques. As a simulation technique one operates with a nonlinear map up to the necessary order of nonlinearity. On the other hand, one can utilize TensorFlow engine to run map optimization and system identification problems.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK088  
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THPMF009 Lattice Options for DIAMOND-II lattice, emittance, injection, sextupole 4050
 
  • B. Singh, R. Bartolini, J. Bengtsson, H. Ghasem
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
  • A. Streun
    PSI, Villigen PSI, Switzerland
  
  Funding: Diamond Light Source Ltd
Generalized MBA (Multi-Bend-Achromat) Chasman-Green type lattices, with a low-dispersion mid-straight, have been studied and refined by pursuing a generalized Higher Order Achromat to control the non-linear dynamics to obtain a robust design. New candidate lattice have been produced aiming for a horizontal emittance of 150 pm×rad for off-axis injection and 75 pm×rad for on-axis, the latter making use of reverse bends. The results of these studies and evaluations have been summarized in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF009  
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THPMK121 Design of the Second Version of the HALS Storage Ring Lattice lattice, emittance, storage-ring, dipole 4601
 
  • Z.H. Bai, W. Li, L. Wang, P.H. Yang, Z.H. Yang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  In this paper, a new multi-bend achromat (MBA) lat-tice concept that we recently proposed for diffraction-limited storage rings is described, where two pairs of interleaved dispersion bumps are created in each cell and also most of the nonlinear effects produced by the sextupoles located in these bumps can be cancelled out within one cell. Following this concept, two 7BA lattices have been designed for the Hefei Advanced Light Source storage ring as the second version lattic-es, one with uniform dipoles and the other with nonu-niform dipoles. The latter has a lower natural emit-tance of 23 pm·rad, in which longitudinal gradient bends and anti-bends are employed. The optimized nonlinear dynamics for these two lattices are rather good, and especially the dynamic momentum aperture can be larger than 8% without off-momentum tunes crossing non-structure half-integer resonance lines.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK121  
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