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Title: Final Report for Cloud-based design of high average power traveling wave linacs

Abstract

Goals of the HEP accelerator stewardship program include: enhance capabilities of US industry; prototype applications in 5 to 7 years; and provide the R&D necessary for innovation. Relevant applications include: treatment of potable and waste water, removal of pollutants from stack gases, increased efficiency of material processing; and replacement of radioactive sources in sterilization applications. These applications involve exposing large mass streams to kGy-class radiation fields, which requires: high average electron beam power from 0.5 to 10 MW; wall plug efficiency of 50% or more; operation in harsh industrial settings; and low capital and operating costs. The most promising solution for high-current applications is to use traveling-wave (TW) RF structures with modest accelerating gradient. Acceleration of high beam current reduces power flow in the accelerating waveguide. This reduces the accelerating electric field amplitude and, hence, the output beam energy. For industrial accelerators, the beam power constitutes a considerable fraction of input RF power. Under certain conditions, electron bunches can excite asymmetric waves with a radial on-axis component. Such waves deflect the beam away from the waveguide axis, which can lead to catastrophic beam loss. Accurate treatment of beam loading (and its inverse) is central to the design of high-power TWmore » accelerators and to high-efficiency klystrons, respectively. Accurate modeling for linacs is especially difficult in the meter-scale region where the electrons are nonrelativistic. The Hellweg code is uniquely capable of providing the basis for an affordable design tool, which offers correct physics, rapid parameter scans and (in the future) interactive nonlinear optimization. The speed required is only possible if minimally sufficient physics is implemented using innovative algorithms. The key differentiator from other codes is that Hellweg uses equations of motion which explicitly include the particle-field coupling of beam loading (and its inverse). The Hellweg code was improved in many ways: a) converted the equations of motion from 2D cylindrical to 3D; b) enhanced parametrization of solenoid fields and added fringe fields; c) improved the space charge model from 2D to a 3D uniformly ellipsoid model with fields outside the bunch; d) added import and export of beam data to/from CST Particle Studio; e) added import of 1D, 2D and 3D magnetic field maps; and f) added quadrupole magnets. We also added new visualization capabilities to the Windows-only GUI, and developed a browser-based GUI, which exports Python script for command-line use. The new code is open source, freely available on GitHub, and the browser-based GUI is in open beta testing. The market for medical and industrial accelerators currently exceeds $3.5 billion dollars a year, and it is growing at more than ten percent annually. Our commercialization strategy is to offer our design and validation expertise to linac manufacturers. As a part of that strategy, we will share our simulations through Sirepo. This hook will enable us to work closely with our customers and build long-lasting relationships.« less

Authors:
 [1]
  1. RadiaSoft, LLC, Boulder, CO (United States)
Publication Date:
Research Org.:
RadiaSoft, LLC, Boulder, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1419850
Report Number(s):
Final report
7008
DOE Contract Number:  
SC0015897
Type / Phase:
SBIR (Phase I)
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
97 MATHEMATICS AND COMPUTING; cloud computing; high-average-power electron linac; linear accelerator; industrial linac; medical linac

Citation Formats

Bruhwiler, David L. Final Report for Cloud-based design of high average power traveling wave linacs. United States: N. p., 2017. Web.
Bruhwiler, David L. Final Report for Cloud-based design of high average power traveling wave linacs. United States.
Bruhwiler, David L. Tue . "Final Report for Cloud-based design of high average power traveling wave linacs". United States.
@article{osti_1419850,
title = {Final Report for Cloud-based design of high average power traveling wave linacs},
author = {Bruhwiler, David L.},
abstractNote = {Goals of the HEP accelerator stewardship program include: enhance capabilities of US industry; prototype applications in 5 to 7 years; and provide the R&D necessary for innovation. Relevant applications include: treatment of potable and waste water, removal of pollutants from stack gases, increased efficiency of material processing; and replacement of radioactive sources in sterilization applications. These applications involve exposing large mass streams to kGy-class radiation fields, which requires: high average electron beam power from 0.5 to 10 MW; wall plug efficiency of 50% or more; operation in harsh industrial settings; and low capital and operating costs. The most promising solution for high-current applications is to use traveling-wave (TW) RF structures with modest accelerating gradient. Acceleration of high beam current reduces power flow in the accelerating waveguide. This reduces the accelerating electric field amplitude and, hence, the output beam energy. For industrial accelerators, the beam power constitutes a considerable fraction of input RF power. Under certain conditions, electron bunches can excite asymmetric waves with a radial on-axis component. Such waves deflect the beam away from the waveguide axis, which can lead to catastrophic beam loss. Accurate treatment of beam loading (and its inverse) is central to the design of high-power TW accelerators and to high-efficiency klystrons, respectively. Accurate modeling for linacs is especially difficult in the meter-scale region where the electrons are nonrelativistic. The Hellweg code is uniquely capable of providing the basis for an affordable design tool, which offers correct physics, rapid parameter scans and (in the future) interactive nonlinear optimization. The speed required is only possible if minimally sufficient physics is implemented using innovative algorithms. The key differentiator from other codes is that Hellweg uses equations of motion which explicitly include the particle-field coupling of beam loading (and its inverse). The Hellweg code was improved in many ways: a) converted the equations of motion from 2D cylindrical to 3D; b) enhanced parametrization of solenoid fields and added fringe fields; c) improved the space charge model from 2D to a 3D uniformly ellipsoid model with fields outside the bunch; d) added import and export of beam data to/from CST Particle Studio; e) added import of 1D, 2D and 3D magnetic field maps; and f) added quadrupole magnets. We also added new visualization capabilities to the Windows-only GUI, and developed a browser-based GUI, which exports Python script for command-line use. The new code is open source, freely available on GitHub, and the browser-based GUI is in open beta testing. The market for medical and industrial accelerators currently exceeds $3.5 billion dollars a year, and it is growing at more than ten percent annually. Our commercialization strategy is to offer our design and validation expertise to linac manufacturers. As a part of that strategy, we will share our simulations through Sirepo. This hook will enable us to work closely with our customers and build long-lasting relationships.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2017},
month = {4}
}

Technical Report:
This technical report may be released as soon as February 8, 2022
Other availability
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