Author: Evans, N.J.
Paper Title Page
TUC3I3 Laser Stripping of H⁻ Beam 141
 
  • T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, Y. Liu, A.R. Oguz
    ORNL, Oak Ridge, Tennessee, USA
  • N.J. Evans
    ORNL RAD, Oak Ridge, Tennessee, USA
  • P.K. Saha
    JAEA/J-PARC, Tokai-mura, Japan
  
  Basic principles of laser assisted charge exchange injection for H⁻ ion andH0 beams are presented. Theoretical aspects of electromagnetic interaction of laser with hydrogen atom and H⁻ ions are discussed. Laser excitation, photoionizatio and interaction of atoms and ions with a strong electro-magnetic field are discussed and compared. Different techniques of LACE for stripping of high current stochastic beams are presented. The optimum parameters of LACE are estimated and compared for various ion beam energies. Experimental development of laser stripping at the SNS are reviewed. Future plans of LACE at the SNS and J-PARC are discussed.  
slides icon Slides TUC3I3 [1.790 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC3I3  
About • Received ※ 04 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 01 November 2023
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WEC2C2
 Two-Dimensional Temperature Measurements of Nanocrystalline Diamond Stripper Foils at High Intensity Hydrogen Ion Beams at SNS  
 
  • A.R. Oguz, W. Blokland
    ORNL, Oak Ridge, Tennessee, USA
  • N.J. Evans
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
We propose and demonstrate a time-resolved, two-dimensional temperature monitoring technique for nanocrystalline diamond stripper foils exposed to high-intensity H- beams at the Spallation Neutron Source (SNS) accumulator ring. The technique utilizes a two-color imaging pyrometer in the shortwave infrared (SWIR) spectral band to measure thermal radiation from stripper foils located 40 meters away from the measurement site. This work presents a unique optical design, optical calibration of the system using a high-temperature blackbody source, preliminary temperature measurement results from two stripper foils (new and used) under various H- production beam conditions with average powers up to 1.7~MW and energy of 1.0~GeV. The technique we developed could be utilized to understand the thermal behavior of charge strippers under high-intensity particle beams and may lead to significant improvements in their lifetime in high-intensity particle accelerator. 		 
slides icon Slides WEC2C2 [7.747 MB]  
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WEC3I1 Self-Consistent Injection Painting for Space Charge Mitigation 258
 
  • N.J. Evans, V.S. Morozov
    ORNL RAD, Oak Ridge, Tennessee, USA
  • T.V. Gorlov, A.M. Hoover
    ORNL, Oak Ridge, TN, USA
  
  Funding: This work was conducted at UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy, with partial funding provided by Field Work Proposal ORNL-ERKCS41.
I will present results of experiments at the Spallation Neutron Source to implement a method of phase space painting we refer to as ¿eigenpainting¿, in which beam is injected along one eigenvector of the transfer matrix of a ring with full coupling.  The method and resultant distribution were initially proposed by Danilov almost to linearize the space charge force, minimizing space charge tune spread. In the theoretically ideal case this so-called Danilov distribution has uniform charge distribution, elliptical envelope in real-space, and a vanishing 4D transverse emittance. Such a beam can be maintained throughout injection. The Danilov distribution has implications for increasing beam intensity beyond the conventional space charge limit through a reduction of both tune spread and shift, and increasing collider performance. This talk will present current limits on beam quality, and details of the preparation of the optics in the SNS accumulator ring, including the installation of new solenoid magnets. The status of experiments to improve beam quality and characterize the interesting dynamical implications of the defining features of the Danilov distribution will also be discussed. 		 
slides icon Slides WEC3I1 [2.687 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3I1  
About • Received ※ 28 September 2023 — Revised ※ 10 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023
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FRA2I2 Summary of the Working Group B 666
 
  • N.J. Evans
    ORNL RAD, Oak Ridge, Tennessee, USA
  • F. Bouly
    LPSC, Grenoble Cedex, France
  • H.W. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
  
  Summary of the Working Group on Beam Dynamics in Linacs.  
slides icon Slides FRA2I2 [1.306 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I2  
About • Received ※ 23 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 24 January 2024  
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