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Title: TH-C-12A-08: New Compact 10 MV S-Band Linear Accelerator: 3D Finite-Element Design and Monte Carlo Dose Simulations

Abstract

Purpose: To design a new compact S-band linac waveguide capable of producing a 10 MV x-ray beam, while maintaining the length (27.5 cm) of current 6 MV waveguides. This will allow higher x-ray energies to be used in our linac-MRI systems with the same footprint. Methods: Finite element software COMSOL Multiphysics was used to design an accelerator cavity matching one published in an experiment breakdown study, to ensure that our modeled cavities do not exceed the threshold electric fields published. This cavity was used as the basis for designing an accelerator waveguide, where each cavity of the full waveguide was tuned to resonate at 2.997 GHz by adjusting the cavity diameter. The RF field solution within the waveguide was calculated, and together with an electron-gun phase space generated using Opera3D/SCALA, were input into electron tracking software PARMELA to compute the electron phase space striking the x-ray target. This target phase space was then used in BEAM Monte Carlo simulations to generate percent depth doses curves for this new linac, which were then used to re-optimize the waveguide geometry. Results: The shunt impedance, Q-factor, and peak-to-mean electric field ratio were matched to those published for the breakdown study to within 0.1%more » error. After tuning the full waveguide, the peak surface fields are calculated to be 207 MV/m, 13% below the breakdown threshold, and a d-max depth of 2.42 cm, a D10/20 value of 1.59, compared to 2.45 cm and 1.59, respectively, for the simulated Varian 10 MV linac and brehmsstrahlung production efficiency 20% lower than a simulated Varian 10 MV linac. Conclusion: This work demonstrates the design of a functional 27.5 cm waveguide producing 10 MV photons with characteristics similar to a Varian 10 MV linac.« less

Authors:
; ; ;  [1]
  1. Cross Cancer Institute, Edmonton, AB (Canada)
Publication Date:
OSTI Identifier:
22412384
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 41; Journal Issue: 6; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
07 ISOTOPES AND RADIATION SOURCES; COMPUTERIZED SIMULATION; DEPTH DOSE DISTRIBUTIONS; FINITE ELEMENT METHOD; LINEAR ACCELERATORS; MEV RANGE 01-10; MONTE CARLO METHOD; NMR IMAGING; PHASE SPACE

Citation Formats

Baillie, D, St Aubin, J, Fallone, B, and Steciw, S. TH-C-12A-08: New Compact 10 MV S-Band Linear Accelerator: 3D Finite-Element Design and Monte Carlo Dose Simulations. United States: N. p., 2014. Web. doi:10.1118/1.4889644.
Baillie, D, St Aubin, J, Fallone, B, & Steciw, S. TH-C-12A-08: New Compact 10 MV S-Band Linear Accelerator: 3D Finite-Element Design and Monte Carlo Dose Simulations. United States. https://doi.org/10.1118/1.4889644
Baillie, D, St Aubin, J, Fallone, B, and Steciw, S. 2014. "TH-C-12A-08: New Compact 10 MV S-Band Linear Accelerator: 3D Finite-Element Design and Monte Carlo Dose Simulations". United States. https://doi.org/10.1118/1.4889644.
@article{osti_22412384,
title = {TH-C-12A-08: New Compact 10 MV S-Band Linear Accelerator: 3D Finite-Element Design and Monte Carlo Dose Simulations},
author = {Baillie, D and St Aubin, J and Fallone, B and Steciw, S},
abstractNote = {Purpose: To design a new compact S-band linac waveguide capable of producing a 10 MV x-ray beam, while maintaining the length (27.5 cm) of current 6 MV waveguides. This will allow higher x-ray energies to be used in our linac-MRI systems with the same footprint. Methods: Finite element software COMSOL Multiphysics was used to design an accelerator cavity matching one published in an experiment breakdown study, to ensure that our modeled cavities do not exceed the threshold electric fields published. This cavity was used as the basis for designing an accelerator waveguide, where each cavity of the full waveguide was tuned to resonate at 2.997 GHz by adjusting the cavity diameter. The RF field solution within the waveguide was calculated, and together with an electron-gun phase space generated using Opera3D/SCALA, were input into electron tracking software PARMELA to compute the electron phase space striking the x-ray target. This target phase space was then used in BEAM Monte Carlo simulations to generate percent depth doses curves for this new linac, which were then used to re-optimize the waveguide geometry. Results: The shunt impedance, Q-factor, and peak-to-mean electric field ratio were matched to those published for the breakdown study to within 0.1% error. After tuning the full waveguide, the peak surface fields are calculated to be 207 MV/m, 13% below the breakdown threshold, and a d-max depth of 2.42 cm, a D10/20 value of 1.59, compared to 2.45 cm and 1.59, respectively, for the simulated Varian 10 MV linac and brehmsstrahlung production efficiency 20% lower than a simulated Varian 10 MV linac. Conclusion: This work demonstrates the design of a functional 27.5 cm waveguide producing 10 MV photons with characteristics similar to a Varian 10 MV linac.},
doi = {10.1118/1.4889644},
url = {https://www.osti.gov/biblio/22412384}, journal = {Medical Physics},
issn = {0094-2405},
number = 6,
volume = 41,
place = {United States},
year = {Sun Jun 15 00:00:00 EDT 2014},
month = {Sun Jun 15 00:00:00 EDT 2014}
}