Author: Ehrlichman, M.P.
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MOPGW100 Bypass Design for Testing Optical Stochastic Cooling at the Cornell Electron Storage Ring (CESR) 360
SUSPFO048   use link to see paper's listing under its alternate paper code  
 
  • W.F. Bergan, M.B. Andorf, M.P. Ehrlichman, V. Khachatryan, D. L. Rubin, S. Wang
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: NSF-1734189 DGE-1650441
Optical Stochastic Cooling (OSC) is a promising method for cooling very dense stored particle beams through the interference of radiation created in an upstream ’pickup’ wiggler and a downstream ’kicker’ wiggler. By correlating a particle’s path length via a bypass between the two wigglers with its betatron coordinates in the pickup, the particle will receive a kick in energy which, through coupling introduced by non-zero horizontal dispersion in the kicker, can reduce its betatron amplitude, thus cooling the beam. A proof-of-principle test of this technique is being planned at the Cornell Electron Storage Ring (CESR). In addition to maintaining standard requirements such as a large dynamic aperture and acceptable lattice functions throughout the ring, the design of the bypass is guided by the mutually competing goals of maximizing the cooling rate while maintaining a sufficiently large cooling acceptance with properly-corrected nonlinearities. We present a design of such a bypass and ring optics so as to best achieve these objectives.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW100  
About • paper received ※ 14 May 2019       paper accepted ※ 19 May 2019       issue date ※ 21 June 2019  
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TUPGW022 Commissioning Simulation Study for the Accumulator Ring of the Advanced Light Source Upgrade 1445
 
  • T. Hellert, Ph. Amstutz, M.P. Ehrlichman, S.C. Leemann, C. Steier, C. Sun, M. Venturini
    LBNL, Berkeley, California, USA
 
  The Advanced Light Source Upgrade (ALS-U) to a diffraction-limited soft x-rays light source requires the construction of an Accumulator Ring (AR) to enable swap-out, on-axis injection. The AR lattice is a Triple-Bend-Achromat lattice similar to that of the current ALS but to minimize the magnet sizes the vacuum chamber will be significantly narrower hence requiring a careful evaluation of the magnets’ field quality. This work presents the results of a detailed error tolerance study including a complete simulation of the commissioning process.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW022  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW093 Compensation of Insertion Device Induced Emittance Variations in Ultralow Emittance Storage Rings by a Dispersion Bump in a Wiggler 1627
 
  • F. Sannibale, M.P. Ehrlichman, T. Hellert, S.C. Leemann, D. Robin, C. Steier, C. Sun, M. Venturini
    LBNL, Berkeley, California, USA
 
  Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
Multi-bend achromat lattices allow for the design of extremely low emittance electron storage rings and hence for the realization of extremely high- brightness X-ray photon sources. In these new rings, the beam energy lost to radiation in the insertion devices (IDs) is often comparable to that lost in the ring dipole magnets. This implies that with respect to the typical 3rd generation light source, these new machines are more sensitive to the energy loss variations randomly occurring as the many users independently operate the gap of their IDs. The consequent induced variations in radiation damping time, equilibrium emittance, and transverse beam sizes at the radiation point sources can be significant and degrade the experimental performance in some of the beam-lines. In this paper we describe and discuss a possible method to compensate for such emittance variations by using a variable dispersion bump localized inside a fixed gap wiggler.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW093  
About • paper received ※ 13 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW094 First Attempts at Applying Machine Learning to ALS Storage Ring Stabilization 1631
 
  • S.C. Leemann, Ph. Amstutz, M.P. Ehrlichman, T. Hellert, A. Hexemer, S. Liu, M. Marcus, C.N. Melton, H. Nishimura, G. Penn, F. Sannibale, D.A. Shapiro, C. Sun, D. Ushizima, M. Venturini
    LBNL, Berkeley, California, USA
 
  Funding: This research is funded by US Department of Energy (BES & ASCR Programs), and supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231.
The ALS storage ring operates multiple feedbacks and feed-forwards during user operations to ensure that various source properties such as beam position, beam angle, and beam size are maintained constant. Without these active corrections, strong perturbations of the electron beam would result from constantly varying ID gaps and phases. An important part of the ID gap/phase compensation requires recording feed-forward tables. While recording such tables takes a lot of time during dedicated machine shifts, the resulting compensation data is imperfect due to machine drift both during and after recording of the table. Since it is impractical to repeat recording feed-forward tables on a more frequent basis, we have decided to employ Machine Learning techniques to improve ID compensation in order to stabilize electron beam properties at the source points.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW094  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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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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