Author: Lewellen, J.W.
Paper Title Page
MOPAB146 Status of the C-Band Engineering Research Facility (CERF-NM) Test Stand Development at LANL 509
 
  • D. Gorelov
    Private Address, Los Alamos, USA
  • R.L. Fleming, S.K. Lawrence, J.W. Lewellen, D. Perez, M.E. Schneider, E.I. Simakov, T. Tajima
    LANL, Los Alamos, New Mexico, USA
  • M.E. Middendorf
    ANL, Lemont, Illinois, USA
 
  Funding: LDRD-DR Project 20200057DR
C-Band structures research is of increasing interest to the accelerator community. The RF frequency range of 4-6 GHz gives the opportunity to achieve significant increase in the accelerating gradient, and having the wakefields at the manageable levels, while keeping the geometric dimensions of the structure technologically convenient. Strong team of scientists, including theorists researching properties of metals under stressful thermal conditions and high electromagnetic fields, metallurgists working with copper as well as alloys of interest, and accelerator scientists developing new structure designs, is formed at LANL to develop a CERF-NM facility. A 50 MW, 5.712 GHz Canon klystron, was purchased in 2019, and laid the basis for this facility. As of Jan-21, the construction of the Test Stand has been finished and the high gradient processing of the waveguide components has been started. Future plans include high gradient testing of various accelerating structures, including benchmark C-band accelerating cavity, a proton ß=0.5 cavity, and cavities made from different alloys. An upgrade to the facility is planned to allow for testing accelerator cavities at cryogenic temperatures.
 
poster icon Poster MOPAB146 [3.778 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB146  
About • paper received ※ 17 May 2021       paper accepted ※ 26 May 2021       issue date ※ 19 August 2021  
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MOPAB341 First C-Band High Gradient Cavity Testing Results at LANL 1057
 
  • E.I. Simakov, R.L. Fleming, D. Gorelov, T.A. Jankowski, M.F. Kirshner, J.W. Lewellen, J.D. Pizzolatto, M.E. Schneider, T. Tajima
    LANL, Los Alamos, New Mexico, USA
  • X. Lu, E.A. Nanni, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  • M.E. Middendorf
    ANL, Lemont, Illinois, USA
 
  Funding: Los Alamos National Laboratory LDRD Program.
This poster will report the results of high gradient testing of the two proton β=0.5 C-band accelerating cavities. The cavities for proton acceleration were fabricated at SLAC and tested at high gradient C-band accelerator test stand at LANL. One cavity was made of copper, and the second was made of a copper-silver alloy. LANL test stand was constructed around a 50 MW, 5.712 GHz Canon klystron and is capable to provide power for conditioning single cell accelerating cavities for operation at surface electric fields up to 300 MV/m. These β=0.5 C-band cavities were the first two cavities tested on LANL C-band test stand. The presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during the high power operation.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB341  
About • paper received ※ 19 May 2021       paper accepted ※ 25 May 2021       issue date ※ 30 August 2021  
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MOPAB342 Design, Fabrication, and Commissioning of the Mode Launchers for High Gradient C-Band Cavity Testing at LANL 1060
 
  • E.I. Simakov, J.E. Acosta, D. Gorelov, M.F. Kirshner, J.W. Lewellen
    LANL, Los Alamos, New Mexico, USA
  • P. Borchard
    Dymenso LLC, San Francisco, USA
  • M.E. Schneider
    MSU, East Lansing, Michigan, USA
 
  Funding: Los Alamos National Laboratory LDRD Program.
This poster will report on the design, fabrication, and operation status of the new high gradient C-band TM01 mode launchers for the high gradient C-band test stand at LANL. Modern applications require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. At LANL we commissioned a test stand powered by a 50 MW, 5.712 GHz Canon klystron. The test is capable of conditioning single cell accelerating cavities for operation at surface electric fields up to 300 MV/m. The rf field is coupled into the cavity from a WR187 waveguide through a mode launcher that converts the fundamental mode of the rectangular waveguide into the TM01 mode of the circular waveguide. Several designs for mode launchers were considered and the final design was chosen based on a compromise between the field enhancements, bandwidth, and simplicity and cost of fabrication. Four mode launchers were fabricated and cold-tested. Two mode launchers with the best transmission characteristics were installed and conditioned to high power. The presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during operation.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB342  
About • paper received ※ 19 May 2021       paper accepted ※ 25 May 2021       issue date ※ 19 August 2021  
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MOPAB371 A Coupon Tester for Normal Conducting High-Gradient Materials 1147
 
  • J.W. Lewellen, D. Gorelov, D. Perez, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • M.E. Schneider
    Michigan State University, East Lansing, Michigan, USA
 
  Funding: Los Alamos National Laboratory LDRD Program
A coupon tester is an RF structure used to subject a material sample to very high RF fields, with the fields on the sample, or coupon, being higher than elsewhere in the cavity. To date, most such cavities were originally intended to explore the RF properties of superconducting materials, and can expose the sample to strong magnetic fields, but weak to no electric fields. As part of a program to develop materials and structures for high-gradient (> 100 MV/m), low-breakdown-rate normal-conducting accelerators, we have designed a C-band (5.712 GHz) cavity intended to subject samples to both magnetic and electric fields comparable to those experienced in high-gradient structure designs, using a TM-mode cavity; the electric and magnetic fields along the sample coupon can be directly compared to the fields on the iris of high-gradient structures. This poster will present the design criteria for our coupon tester cavity, nominal operating parameters, and our structure concept. The cavity design will be refined over the next several months, and will be constructed and in service near the start of 2022.
 
poster icon Poster MOPAB371 [0.764 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB371  
About • paper received ※ 17 May 2021       paper accepted ※ 26 May 2021       issue date ※ 30 August 2021  
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MOPAB372 KARVE: A Nanoparticle Accelerator for Space Thruster Applications 1151
 
  • J.W. Lewellen, L.R. Danielson, A. Essunfeld, J.A. Hollingsworth, M.A. Holloway
    LANL, Los Alamos, New Mexico, USA
  • E.K. Lewis
    NASA Johnson Space Center, Houston, Texas, USA
 
  We present a concept for using RF-based acceleration of nanoparticles (NPs) as a means of generating thrust for future space missions: the Kinetic Acceleration & Resource Vector Engine (KARVE) thruster. Acceleration of nanoparticles (NPs) via DC accelerators has been shown to be feasible in dust accelerator labs such as the Heidelberg dust accelerator and the 3 MV hypervelocity dust accelerator at the Colorado Center for Lunar Dust and Atmospheric Studies. In contrast, KARVE uses RF-driven acceleration of nanoparticles as the basis of a thruster design lying between chemical and ion engines in performance: more efficient than chemical engines in terms of specific impulse; and higher thrust than ion engines. The properties of multi-gap RF accelerators also allow an on-the-fly tradeoff between specific impulse and thrust.  
poster icon Poster MOPAB372 [0.694 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB372  
About • paper received ※ 19 May 2021       paper accepted ※ 27 May 2021       issue date ※ 10 August 2021  
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TUPAB205 Advancement of LANSCE Front End Accelerator Facility 1894
 
  • Y.K. Batygin, D. Gorelov, S.S. Kurennoy, J.W. Lewellen, N.A. Moody, L. Rybarcyk
    LANL, Los Alamos, New Mexico, USA
 
  Funding: Work supported by US DOE under contract 89233218CNA000001
The LANSCE accelerator started routine operation in 1972 as a high-power facility for fundamental research and national security applications. To reduce long-term operational risk, we propose to develop a new Front End of accelerator facility. It contains 100-keV injector with 3-MeV RFQ, and 6-tanks Drift Tube Linac to accelerate particles up to energy of 100 MeV. The low-energy injector concept includes two independent transports merging H+ and H beams at the entrance of RFQ. Beamlines are aimed to perform preliminary beam bunching in front of accelerator section with subsequent simultaneous acceleration of two different beams in a single RFQ. The paper discusses design topics of new Front End of accelerator facility.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB205  
About • paper received ※ 12 May 2021       paper accepted ※ 28 May 2021       issue date ※ 14 August 2021  
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THPAB138 FEbreak: A Comprehensive Diagnostic and Automated Conditioning Interface for Analysis of Breakdown and Dark Current Effects 4027
 
  • M.E. Schneider, S.V. Baryshev
    Michigan State University, East Lansing, Michigan, USA
  • R.L. Fleming, D. Gorelov, J.W. Lewellen, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • E. Jevarjian
    MSU, East Lansing, Michigan, USA
 
  Funding: DE-AC02-06CH11357, No. DE-SC0018362, DE-NA-0003525, DE-AC52-06NA25396, LA-UR-21-20613
As the next generation of accelerator technology pushes towards being able to achieve higher and higher gradients there is a need to develop high-frequency structures that can support these fields *. The conditioning process of the structures and waveguides to high gradient is a labor-intensive process, its length increases as the maximum gradient is increased. This results in the need to automate the conditioning process. This automation must allow for high accuracy calculations of the breakdown probabilities associated with the conditioning process which can be used to instruct the conditioning procedure without the need for human intervention. To automate the conditioning process at LANL’s high gradient C-band accelerator test stand we developed FEbreak that is a breakout probability and conditioning automation software that is a part of the FEmaster series **, ***, ****. FEbreak directly interfaces with the rest of FEmaster to automate the data collection and data processing to not only analyze the breakdown probability but also the dark current effects associated with these high gradient structures.
* E. I. Simakov Nuc. Inst. and Meth, in Phy. Research Section A: Acc. Spec, 907 221 (2019)
** E. Jevarjian arXiv:2009.13046
*** T. Y. Posos arXiv:2012.03578
**** M. Schneider arXiv:2012.10804
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB138  
About • paper received ※ 18 May 2021       paper accepted ※ 02 July 2021       issue date ※ 16 August 2021  
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THPAB153 Design, Construction and Tests of the Cooling System with a Cryocooler for Cavity Testing 4056
 
  • P. Pizzol, J.W. Lewellen, E.R. Olivas, E.I. Simakov, T. Tajima
    LANL, Los Alamos, New Mexico, USA
 
  Cryogenically cooled normal-conducting cavities have shown higher gradients than those operated at room temperature. We are constructing a compact cooling system with a cryocooler to test C-band normal-conducting cavities and 1.3 GHz superconducting cavities. This paper describes the design, construction, and cooling test results as well as some low-power cavity Q measurement results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB153  
About • paper received ※ 17 May 2021       paper accepted ※ 21 June 2021       issue date ※ 12 August 2021  
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