THE EGS5 CODE SYSTEM - KEK

1 THE egs5 code SYSTEM1 Hideo Hirayama and Yoshihito NamitoRadiation Science CenterAdvanced Research LaboratoryHigh Energy Accelerator Research Organization (KEK)1-1 Oho Tsukuba-shi Ibaraki-ken 305-0801 JAPANAlex F. Bielajew and Scott J. WildermanDepartment of Nuclear Engineering and Radiological SciencesThe University of Michigan2355 Bonisteel BoulevardAnn Arbor, MI 48109, USAW alter R. NelsonDepartment Associate in the Radiation Physics Group (retired)Radiation Protection DepartmentStanford Linear Accelerator CenterStanford University2575 Sand Hill Road, Menlo Park, CA 94025, USASLAC Report number: SLAC-R-730 KEK Report number: 2005-8 Date of this version: January 13, 20161 Work supported by the US Department of Energy under DE-AC02-76SF00515 Stanford University Notices forSLAC Manual SLAC-R-730and its included softwareknown as the egs5 code SystemAcknowledgement of sponsorship:This manual and its contents, including software, wereproduced in part by the Stanford Linear Accelerator Center (SLAC), Stanford University, underContract DE-AC02-76 SFO0515 with the Department of :The manual and its included software should be used for non-commercial purposes SLAC regarding commercial disclaimer of liability.

2 Neither the United States nor the United States Depart-ment of Energy, nor any of their employees, makes any warranty, express or implied, or assumes anylegal liability or responsibility for the accuracy, completeness, or usefulness of any data, apparatus,product, or process disclosed, or represents that its use would not infringe privately owned disclaimer of liability:Stanford University makes no representations or warranties,express or implied, nor assumes any liability for the use of this manual or its contents, of notices:In the interest of clarity regarding the origin and status ofthis SLAC manual and its included software, this and all the precedingStanford University notices are to:(1) remain affixed to any copy or derivative of this manual or its software made or distributed bythe recipient of this manual or its software; and (2) be affixedto any copy of a document or anysoftware made or distributed by the recipient that containsa copy or derivative of this manual orits software.

3 From SLAC Software Notices, Set , 2004 FEB 03 KEK Reports are available from:Science Information and Library Services DivisionPhone: +81-29-864-5137 High Energy Accelerator Research Organization (KEK)Fax:+81-29-864-46041-1 Oho, Tsukuba-shiE-Mail: 305-0801 Internet: Intent of This Report .. History of EGS .. Before EGS .. EGS1 .. EGS2 .. EGS3 .. EGS4 .. Overview of the EGS4 code SYSTEM Vintage 1985 .. Improvements to EGS Since 1985 .. Version 5 s Improvements and Enhancements to EGS Electron Physics Mod-eling .. Improvements and Enhancements to EGS Photon Physics Modeling in Ver-sion 5 .. Other Improvements .. 192 RADIATION TRANSPORT IN Description of Radiation Transport-Shower Process .. Probability Theory and Sampling Methods A Short Tutorial .. Simulating the Physical Processes An Overview .. Particle Transport Simulation .. Particle Interactions.

4 General Implementation Notes .. Bremsstrahlung and Electron-Positron Pair Production.. Bremsstrahlung Photon Angular Distribution .. Pair Angle Sampling .. Interactions With Atomic Electrons General Discussion .. Compton Scattering .. M ller Scattering .. Bhabha Scattering .. Two Photon Positron-Electron Annihilation .. Continuous Electron Energy Loss .. Multiple Scattering .. The Moli`ere Multiple Scattering Distribution .. The Goudsmit-Saunderson Multiple Scattering Distribution .. Transport Mechanics in egs5 .. Random Hinge Transport Mechanics .. Modified Random Hinge Transport Mechanics .. Dual Random Hinge Approach .. Boundary Crossing .. egs5 Transport Mechanics Algorithm .. Electron Step-Size Selection .. Energy Hinge Step-Size Determination in PEGS .. Multiple Scattering Step-size Specification Using Fractional Energy Loss Pa-rameters .. Multiple Scattering Step-Size Optimization Using Media Characteristic Di-mensions.

5 Treatment of Initial Steps of Primary Electrons .. Photoelectric Effect .. General Treatment of Photoelectric-Related Phenomena .. Photoelectron Angular Distribution .. Coherent (Rayleigh) Scattering .. Binding Effects and Doppler Broadening in Compton Scattering .. Scattering of Linearly Polarized Photons .. Electron Impact Ionization .. 1423 A SERIES OF SHORT egs5 Tutorial 1 ( ) .. Tutorial 2 ( ) .. Tutorial 3 ( ) .. Tutorial 4 ( ) .. Tutorial 5 ( ) .. Tutorial 6 ( ) .. Tutorial 7 ( ) .. Tutorial 8 ( ) .. 194iv4 ADVANCED egs5 USER UCCYL - Cylinder-Slab Geometry and Importance Sampling.. Generalized Multi-Cylinder, Multi-Slab Geometry .. Particle Splitting .. Leading Particle Biasing .. UCBEND - Charged Particle Transport in a Magnetic Field .. Using Combinatorial Geometry with egs5 .. 213 APPENDICES:218A egs5 FLOW DIAGRAMS218B egs5 USER Introduction .. General Description of Implementation.

6 Variables in egs5 COMMONB locks .. Sequence of Actions Required of User CodeMAIN.. Pre-PEGS5 Initializations (Step 1) .. (Step 2) .. Pre-HATCHI nitializations (Step 3) .. Specification of Incident Particle Parameters (Step 4) .. (Step 5) .. Initializations forHOWFAR(Step 6) .. Initializations forAUSGAB(Step 7) .. (Step 8) .. Output of Results (Step 9) .. Specifications forHOWFAR.. SampleHOWFARUser code .. Specifications forAUSGAB.. UCSAMPL5 An Example of a Complete egs5 User code .. 361C PEGS USER Introduction .. Structural Organization of PEGS .. PEGS Options and Input Specifications .. Interrelations Between Options .. The ELEM, MIXT, COMP Options .. The ENER Option .. The PWLF Option .. The DECK Option .. The TEST Option .. The CALL Option .. The PLTI and PLTN Options .. The HPLT Option .. Concluding Remarks .. 407D egs5 INSTALLATION Installation of egs5 .. Sample Scripts for Running egs5 .

7 409E CONTENTS OF THE egs5 Documentation .. EGS-Related FORTRAN Source Files .. PEGS-Related FORTRAN Source Files .. Material Data Files .. Sample User Codes and Run Scripts .. Auxiliary Subprogram FORTRAN Source Files .. 424viiList of Program flow and data control in egs5 .. Feynman diagrams for bremsstrahlung and pair production.. Feynman diagrams for two body interactions with electrons.. Definition of two-body scattering angles.. Feynman diagram for single photon e+e annihilation.. Plots of Moli`ere functionsf(0), f(1), andf(2).. Plot of Equation (B `n B=b).. Schematic of electron transport mechanics model.. Random hinge transport mechanics schematic.. Modified random hinge transport mechanics schematic.. Dual (energy and angle) hinge transport mechanics schematic.. Electron transport across region boundaries.. Translation steps and transport steps for energy loss hinges.. Electron boundary crossing during translation.

8 Schematic illustrating the broomstick problem.. Schematic illustrating the modified broomstick problem as used in egs5 .. Convergence of energy deposition as a function of step-size (in terms of fractionalenergy loss) for the broomstick problem with varying diametersDin copper at 5 Convergence of average lateral displacement as function of step-size (in terms of frac-tional energy loss) for the broomstick problem with varyingdiametersDin copperat 5 MeV.. Optimal initial scattering strengthK1vs. broomstick diameter (equivalent to thecharacteristic dimension) in titanium at various energies.. Optimal initial scattering strengthK1vs. broomstick diameter for various elementsat 100 MeV. The upper figure is for values of tgreater than , and the lower figurefor smaller characteristic dimensions.. Cu GMFP values evaluated by PWLF and LEM .. Comparison of measured and calculated intensity of K x-rays.. Photon scattering SYSTEM .. Direction of the polarization vector of the scattered photon.

9 Direction of~k0and~e0after two rotations byA 1.. Diagram used with UCBEND (not to scale).. UCBEND simulation at MeV (B= kG).. UCBEND simulation at MeV (B= kG).. UCBEND simulation at MeV (B=0 kG).. Geometry and particle trajectory of UCSAMPCG simulation.. egs5 user code control and data flow diagram.. A three-region geometry for aHOWFAR example code .. Flowchart of thePEGS5subprogram of PEGS, part 1.. Flowchart of thePEGS5subprogram of PEGS, part 2.. Subprogram relationships in PEGS, part 1.. Subprogram relationships in PEGS, part 2.. Bremsstrahlung related functions most accurate form (used to produce the totalcross sections and stopping power).. Bremsstrahlung related functions with run-time approximations (for comparisonwith sampled spectra).. Pair production related functions most accurate form (used to produce the totalcross sections and stopping power).. Pair production related functions with run-time approximations (for comparisonWith sampled spectra).

10 Logical relationship between the options of PEGS.. 388xList of Symbols used in egs5 and PEGS5.. Default atomic numbers, symbols, weights, densities andIvalues in PEGS.. Default Sternheimer density effect coefficients in PEGS.. Materials used in reference tables of scattering strength vs. characteristic dimensionat various energies.. GMFP of Cu atK 1( keV) andK 2( keV) energies.. Data sources for generalized treatment of photoelectric-related phenomena in egs5 . L x-ray energies and representative intensities (relative to L 1) for lead.. Total cross section (10 24cm2/molecule) for coherent scattering from water.. Formulas used in various simulation modes employing detailed treatment of Comptonand Rayleigh scattering.. Variable descriptions forCOMMON blockBOUNDS, theEGS5 distribution.. Variable descriptions forCOMMON blockBREMPR, theEGS5 distribution.. Variable descriptions forCOMMON blockCOUNTERS, theEGS5 distribution.