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Creation of High Energy/Intensity Bremsstrahlung by a Multi-Target and Focusing of the Scattered Electrons by Small-Angle Backscatter at a Cone Wall and a Magnetic Field—Enhancement of the Outcome of Linear Accelerators in Radiotherapy

DOI: 10.4236/ijmpcero.2013.24020, PP. 147-160

Keywords: Multitarget, Bremsstrahlung, Wall Scatter, Focusing by Magnetic Field

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The yield of bremsstrahlung (BS) from collisions of fast electrons (energy at least 6 MeV) with a Tungsten target can be significantly improved by exploitation of Tungsten wall scatter in a multi-layered target. A simplified version of a previously developed principle is also able to focus on small angle scattered electrons by a Tungsten wall. It is necessary that the thickness of each Tungsten layer does not exceed 0.04 mm—a thickness of 0.03 mm is suitable for accelerators in medical physics. Further focusing of electrons results from suitable magnetic fields with field strength between 0.5 Tesla and 1.2 Tesla (if the cone with multi-layered targets is rather narrow). Linear accelerators in radiation therapy only need to be focused by wall scatter without further magnetic fields (a standard case: 31 plates with 0.03 mm thickness and 1 mm distance between the plates). We considered three cases with importance in medical physics: A very small cone with an additional magnetic field for focusing (the field diameter at 90 cm depth: 6 cm), a medium cone with an optional magnetic field (field diameter at 90 cm depth: 13 cm) and a broad cone without a magnetic field (


[1]  [1] R. Svensson and A. Brahme, “Effective Source Size, Yield and Beam Profile from Multi-Layered Bremsstrahlung Targets,” Physics in Medicine and Biology, Vol. 41, No. 8, 1996, pp. 1353-1379.
[2]  W. Ulmer, “On the Creation of High Energy Bremsstrahlung and Intensity by a Multi-Target and Repeated Focusing of the Scattered Electrons by Small-Angle Backscatter at the Wall of a Cone and Magnetic Fields—A Possible Way to Improve Linear Accelerators in Radiotherapy and to Verify Heisenberg-Euler Scatter,” Radiation Physics and Chemistry, Vol. 81, No. 4, 2012, pp. 387-402.
[3]  “GEANT4 Documents,” 2005.
[4]  L. Eyges, “Energy Loss and Scatter of Neutrons and Charged Particles,” Physical Review, Vol. 74, 1948, pp. 1434-1439.
[5]  G. Molière, “Multiple Scatter of Charged Particles Passing through Matter,” Zeitschrift für Naturforschung, Vol. 10a, 1955, pp. 177-187.
[6]  R. P. Feynman and A. R. Hibbs, “Quantum Mechanics and Path Integrals,” Mac Graw Hill, New York, 1965.
[7]  W. Ulmer, J. Pyyry and W. Kaissl, “A 3D Photon Superposition/Convolution Algorithm and Its Foundation on Results of Monte-Carlo Calculations,” Physics in Medicine and Biology, Vol. 50, No. 8, 2005, pp. 1767-1781.
[8]  W. Ulmer, “Inverse Problem of Linear Combinations of Gaussian Convolution Kernels (Deconvolution) and Some Applications to Proton/Photon Dosimetry and Image Processing,” Inverse Problems, Vol. 26, No. 8, 2010, Article ID: 085002.
[9]  W. Ulmer, “Deconvolution of a Linear Combination of Gaussian Kernels by Liouville-Neumann Series Applied to an Integral Equation of Second Kind with Applications to Radiation Physics/Image Processing,” In: A. Mishra, Ed., An Introductory Guide to Digital Image Processing, iConcept Press, 2013.
[10]  W. Ulmer and E. Matsinos, “Theoretical Methods for the Calculation of Bragg Curves and 3D Distributions of Proton beams,” European Physics Journal (ST), Vol. 190, 2011, pp. 1-81.
[11]  M. J. Berger, J. S. Coursey and M. A. Zucker, “ESTAR, PSTAR and ASTAR: Computer Programs for Calculating Stopping-Power and Range Tables for Electrons, Protons and α-Particles (Version 1.2.2),” National Institute of Standards and Technology, Gaithersburg, 2000.
[12]  I. Kawrakow and D. O. Rogers, “The EGSnrc Code System: Monte Carlo Simulation of Electron and Photon Transport,” NRCC Report PIRS-701 NRC Canada, 2000.


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