EGS4(ID:7898/)

Monte Carlo system at SLAC 

Electron Gamma Shower

Evolution of EGS3, Monte Carlo simulation system, developed by SLAC and other international agencies, used MORTRAN 3 to work with F77 and F66

PEGS upgraded to PEGS4 to match

Extensive UserCode library available
Related languages
EGS3 => EGS4   Evolution of
MORTRAN 3 => EGS4   Written using
EGS4 => PEGS 4   Preprocessor for
EGS4 => WinEGS   Augmentation of
References:
  • Nelson, W.Ralph; Hirayama, H.; Rogers, David W.O.; "The EGS4 Code System" SLAC-0265 Dec 1985 view details External link: Online copy External link: Spires page for EGS4
  • Alex F Bielajew, H. Hirayama, W.R. Nelson and D.W.O. Rogers "History, overview and recent improvements of EGS4" Report NRCC/PIRS-0436, June 1994 view details
  • Bielajew, Alex F "An EGS4 Primer" 1997 view details External link: Online copy
  • I. Kawrakow and D.W.O. Rogers "The EGSnrc Code System: Monte Carlo Simulation of Electron and Photon Transport" NRCC Report PIRS-701 view details Abstract: The EGS (Electron-Gamma-Shower) system of computer codes is a general purpose package for the Monte Carlo simulation of the coupled transport of electrons and photons in an arbitrary geometry for particles with energies above a few keV up to several hundreds of GeV. This report introduces a new, enhanced version called EGSnrc. In addition to explaining and documenting the various enhancements and changes to the previous version (EGS4[12]), this document includes several introductory and advanced tutorials on the use of EGSnrc (section 4) and also contains the EGSnrc Reference Manual(section 3), the PEGS4 User Manual (section 6), and an EGS User Guide to Mortran3 (section 7). Our intention has been to make this document wholly self-contained so that the user need not refer to the original EGS4 User Manual[12] although it is on-line and available at http://www.slac.stanford.edu/pubs/slacreports/slac-r-265.html. The heart of the present report is Section 2 which documents the physics in EGSnrc. This has changed substantially from the EGS4 comparable Chapter 2 because of the many changes in EGSnrc. However, we have chosen not to repeat the general introduction to sampling and probability theory that was in Chapter 2 of SLAC-265.

    For a basic introduction to the code, see the reference manual, section 3 (page ).

    We have not presented any comparisons with experiment in this document since it has become such an extensive field that we have no hope of reproducing a fraction of the data. Instead, we have prepared a separate report on QA which presents extensive comparisons between EGS4 and EGSnrc[13] (available on-line via
    http://www.irs.inms.nrc.ca/inms/irs/EGSnrc/EGSnrc.html). There are significant differences in many situations because of the improved physics in EGSnrc. Two papers[5,6] discuss many of the details of the new physics, especially as related to ion chamber calculations (which are perhaps the toughest test of any electron-photon Monte Carlo transport code). These papers provide analytic models which explain many of the shortcomings of the EGS4/PRESTA system in this very difficult problem. The cover of this report shows a comparison of the two codes run in their standard default modes.
    External link: Online copy
    Resources
    • EGS4 manuals etc
      external link
    • EGS4 stuff by Alex F Bielajew
      external link
    • EGS4 people
      The people responsible for EGS4...

      The EGS4 software was developed by Richard Ford, a student of SLAC in the mid-1970's and (Walter) Ralph Nelson, a current employee in the Radiation Protection Group at SLAC, for everyday use at SLAC related to design of experiments.

      Starting in the early 80's Dave Rogers of the National Research Council of Canada in Ottawa, Canada realized that EGS4 had enough content to be of enormous use for medical physics applications. At the same time, Hideo Hirayama of the KEK in Japan, was interested in the low-energy problem as well and so Nelson, Rogers and Hirayama want about making changes to EGS (then EGS3) resulting in the release of EGS4 in December 1985.

      In 1982 Dave Rogers was joined by a recent graduate of Stanford University, Alex Bielajew, a mathematical theorist who was interested in making EGS4 much more reliable for medical-physics applications. The adaptations that resulted in the December 1985 release of EGS4 made it difficult for anyone who was a non-EGSpert to make the code give the correct answers. The result of this work was an adaptation of EGS4 called PRESTA for Parameter Reduced Electron-Step Transport Algorithm. Bielajew has been working on making the calculation of electron problems more accurate and reliable ever since. He also has been responsible for creating and distributing the UNIX and VAX versions of the code.

      Hideo Hirayama was joined by Yoshihito Namito who introduced many important capabilities to the code, particularly in the low-energy photon modeling regime, such as polarization, corrections for atomic binding and Doppler broadening.

      Other people have helped with various aspects of the code development and distribution. Suzan Walker of the Lanzl Institute of Medical Physics in Seattle created and distributes the PC version of the EGS4 code. The Lanzl Institute has also hosted two of the highly successful EGS4 courses, whereby researchers from around the world meet, usually in an attractive location, to learn about the innards of EGS4 and then get hands-on experience with an EGSpert looking over their shoulders.

      Much of the work of distributing and publicizing the EGS4 code have come about from the effort of Rick Donahue and Rob Stewart who maintain the EGS4 Web site. The EGS4 Web site is a primary source of technical information about EGS.

      No one can really claim ownership of EGS4 anymore, although it is copyrighted by Stanford University and the Government of Canada through the National Research Council. It is really the child of a thousand mothers and fathers. One of the best things about EGS4 is that it is free and its design is open so that others can make changes to it easily, after an initial learning period.

      external link
    • Page for RSIC CODE PACKAGE CCC-331 (ie EGS4)
      EGS4: Monte Carlo Simulation of the Coupled Transport of Electrons and Photons

      MORTRAN 3: Macroprocessor to Convert MORTRAN to ANSI Fortran.

      PEGS 4: Data Processor for EGS.

      EGS_Windows: Graphical tool for displaying acceleration and geometry data files.

      NATURE OF PROBLEM SOLVED

      This code system is a general purpose package for the Monte Carlo simulation of the coupled transport of electrons and photons in an arbitrary geometry for particles with energies from a few keV up to several TeV. EGS4 Version 3.0 is available for and Unix workstations, while the PC version is still at Version 2.0. The EGS code system is one of a chain of three codes designed to solve the electromagnetic shower problem by Monte Carlo simulation. This chain makes possible simulation of almost any electron-photon transport problem conceivable. The structure of the system, with its global features, modular form, and structured programming, is readily adaptable to virtually any interfacing scheme that is desired on the part of the user.

      EGS4 is a package of subroutines plus block data with a flexible user interface. This allows for greater flexibility without requiring the user to be overly familiar with the internal details of the code. Combining this with the macro facility capabilities of the Mortran3 language, this reduces the likelihood that user edits will introduce bugs into the code. EGS4 uses material cross section and branching ratio data created and fit by the companion code, PEGS4.

      EGS4 allows for the implementation of importance sampling and other variance reduction techniques such as leading particle biasing, splitting, path length biasing, Russian roulette, etc. A variety of automated data sets is provided. EGS (Electron-Gamma Shower) is based on code development in the early 1960s by H. H. Nagel and represents several years of additional development.

      See the EGS homepage http://www.slac.stanford.edu/egs/ for additional information
      external link