Author: De Santis, S.
Paper Title Page
TUPGW097 Design Progress of ALS-U, the Soft X-ray Diffraction Limited Upgrade of the Advanced Light Source 1639
 
  • C. Steier, Ph. Amstutz, K.M. Baptiste, P.A. Bong, E.S. Buice, P.W. Casey, K. Chow, S. De Santis, R.J. Donahue, M.P. Ehrlichman, J.P. Harkins, T. Hellert, M.J. Johnson, J.-Y. Jung, S.C. Leemann, R.M. Leftwich-Vann, D. Leitner, T.H. Luo, O. Omolayo, J.R. Osborn, G. Penn, G.J. Portmann, D. Robin, F. Sannibale, C. Sun, C.A. Swenson, M. Venturini, S.P. Virostek, W.L. Waldron, E.J. Wallén
    LBNL, Berkeley, California, USA
 
  Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The ALS-U project to upgrade the Advanced Light Source to a multi bend achromat lattice received CD-1 approval in 2018 marking the end of its conceptual design phase. The ALS-U design promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of magnitude brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper presents recent design progress of the accelerator, as well as new results of the mature R&D program.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW097  
About • paper received ※ 21 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPGW110 Feasibility Study of Beam Profile Measurements Using Interferometer and Diffractometer Techniques for ALS-U 2752
 
  • C. Sun, S. De Santis, D. Filippetto, F. Sannibale, C. Steier
    LBNL, Berkeley, California, USA
 
  Funding: Work supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
ALS-U is an ongoing upgrade of Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. The upgraded ALS will replace the existing Triple-Bend Achromat (TBA) storage ring lattice with a compact Multi-Bend Achromat (MBA) lattice. This MBA technology allows us to tightly focus electron beams down to about 10 μm to reach diffraction limit in a soft x-ray region. The beam size measurement is a challenging task for this tightly focused beam. The interferometer technique with visible light from synchrotron radiation has been developed in many facilities to measure their beam size at a micrometer-level accuracy. In this paper, we will present the feasibility study of this technique for the ALS-U storage ring beam size measurement.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW110  
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPRB081 Design Study on Higher Harmonic Cavity for ALS-U 3011
 
  • H.Q. Feng, K.M. Baptiste, S. De Santis, D. Li, T.H. Luo
    LBNL, Berkeley, California, USA
  • H.Q. Feng, W.-H. Huang, Z.N. Liu, C.-X. Tang
    TUB, Beijing, People’s Republic of China
 
  Funding: Director of Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The ALS upgrade (ALS-U) to a diffraction-limited light source [1] depends on the ability to lengthen the stored bunches to limit the emittance growth and increase the beam life time. Higher harmonic cavities (HHCs), also known as Landau cavities, have been proposed to in-crease beam lifetime and Landau damping by lengthen-ing the bunch. We present an optimized 1.5 GHz normal conducting HHC design for the ALS-U with a supercon-ducting-like geometry using multi-objective genetic algorithm (MOGA) for lower R/Q. The optimization goal is to reach the required shunt impedance while maintain-ing a relatively high Q value of the cavities. To minimize the coupled bunch instabilities, higher-order mode (HOM) of the HHC as well as corresponding impedance are explored and characterized.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB081  
About • paper received ※ 16 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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