Author: Moss, J.S.
Paper Title Page
MOPAB335 SNS Warm Linac Circulator Breakdown Considerations for the PPU Project 1041
 
  • G.D. Toby, Y.W. Kang, S.-H. Kim, S.W. Lee, J.S. Moss
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: * This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC05-00OR22725.
Multipacting in accelerating structures is a complex phenomenon about which there is much to be understood. While multipacting research efforts have primarily been focused on superconducting radio frequency (SRF) systems, normal conducting accelerating structures which have a higher thermal capacity, and a greater vacuum pressure tolerance could benefit from additional investigation. This research details multipacting simulation methods and the results of 3-D electromagnetic simulations of RF vacuum windows used on normal conducting linac (NCL) cavities. Benchmarking of the peak electric fields in these structures, benefits of material processing and possible techniques for reducing or eliminating multipacting activities are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB335  
About • paper received ※ 17 May 2021       paper accepted ※ 28 May 2021       issue date ※ 23 August 2021  
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MOPAB336 Multipacting Analysis of Warm Linac RF Vacuum Windows 1044
 
  • G.D. Toby, Y.W. Kang, S.-H. Kim, S.W. Lee, J.S. Moss
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: * This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC05-00OR22725.
Multipacting in accelerating structures is a complex phenomenon with which there is much to be understood. While multipacting research efforts have primarily been focused on superconducting radio frequency (SRF) systems, normal conducting accelerating structures that have a higher thermal capacity and a greater vacuum pressure tolerance could benefit from additional investigation. This research details multipacting simulation methods and the results of 3-D electromagnetic simulations of RF vacuum windows used on normal conducting linac (NCL) cavities. Possible techniques for reducing and eliminating multipacting activities in these structures are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB336  
About • paper received ※ 17 May 2021       paper accepted ※ 28 May 2021       issue date ※ 29 August 2021  
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TUPAB199 Progress on the Proton Power Upgrade at the Spallation Neutron Source 1876
 
  • M.S. Champion, C.N. Barbier, M.S. Connell, J. Galambos, M.P. Howell, S.-H. Kim, J.S. Moss, B.W. Riemer, K.S. White
    ORNL, Oak Ridge, Tennessee, USA
  • E. Daly
    JLab, Newport News, Virginia, USA
  • N.J. Evans, G.D. Johns
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This research was supported by the DOE Office of Science, Basic Energy Science.
The Proton Power Upgrade Project at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory will double the proton power capability from 1.4 to 2.8 MW. This will be accomplished through an energy increase from 1.0 to 1.3 GeV and a beam current increase from 26 to 38 mA. The energy increase will be accomplished through the addition of 7 cryomodules to the linear accelerator (Linac). The beam current increase will be supported by upgrading several radio-frequency systems in the normal-conducting section of the Linac. Upgrades to the accumulator ring injection and extraction regions will accommodate the increase in beam energy. A new 2-MW-capable target and supporting systems will be developed and installed. Conventional facility upgrades include build-out of the existing klystron gallery and construction of a tunnel stub to facilitate future beam transport to the second target station. The project received approval to proceed with construction in October 2020. Procurements are in progress, and some installation activities have already occurred. Most of the installation will take place during three outages in 2022-2023. The project early finish is planned for 2025.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB199  
About • paper received ※ 10 May 2021       paper accepted ※ 28 May 2021       issue date ※ 21 August 2021  
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WEPAB299 Spallation Neutron Source Proton Power Upgrade Low-Level RF Control System Development 3363
 
  • M.T. Crofford, J.A. Ball, J.E. Breeding, M.P. Martinez, J.S. Moss, M. Musrock
    ORNL, Oak Ridge, Tennessee, USA
  • L.R. Doolittle, C. Serrano, V.K. Vytla
    LBNL, Berkeley, California, USA
  • J. Graham, C.K. Roberts, J.W. Sinclair, Z. Sorrell, S. Whaley
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: * This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC05-00OR22725.
The Proton Power Upgrade (PPU) Project is approved for the Spallation Neutron Source at Oak Ridge National Laboratory and will double the proton beam power capability from 1.4 MW to 2.8 MW with 2 MW beam power available to the first target station. A second target station is planned and will utilize the remaining beam power in the future. The proton power increase will be supported with the addition of twenty-eight new superconducting cavities powered by 700 kW peak power klystrons to increase beam energy while increases to the beam current will be done with a combination of existing RF margin, and DTL HPRF upgrades. The original low-level RF control system has proven to be reliable over the past 15 years of operations, but obsolescence issues mandate a replacement system be developed for the PPU project. The replacement system is realized in a µTCA.4 platform using a combination of commercial off-the-shelf boards and custom hardware to support the requirements of PPU. This paper presents the prototype hardware, firmware, and software development activities along with preliminary testing results of the new system.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB299  
About • paper received ※ 18 May 2021       paper accepted ※ 21 June 2021       issue date ※ 11 August 2021  
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THPAB296 The Spallation Neutron Source Normal Conducting Linac RF System Design for the Proton Power Upgrade Project 4383
 
  • J.S. Moss, M.T. Crofford, S.W. Lee, G.D. Toby
    ORNL, Oak Ridge, Tennessee, USA
  • M.E. Middendorf
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC05-00OR22725.
The Proton Power Upgrade (PPU) project at the Spallation Neutron Source will double the available proton beam power from 1.4 to 2.8 MW by increasing the beam energy from 1.0 to 1.3 GeV and the beam current from 26 to 38 mA. The increase in beam current resulted in the need to redesign the existing normal conducting linac (NCL) RF Systems. High-power testing of the existing NCL RF Systems configured to accelerate PPU-level beam provided the data used to make the final design decisions. This paper describes the development and execution of those in-situ tests and the subsequent results.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB296  
About • paper received ※ 17 May 2021       paper accepted ※ 22 July 2021       issue date ※ 20 August 2021  
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