1. NAME AND TITLE

PENELOPE-2001: Code System to Perform Monte Carlo Simulation of Electron Gamma-Ray Showers in Arbitrary Materials.
 
RSICC distributes Penelope 2001 and a modified version called Penelope-MPI. Newer versions of PENELOPE are available from the NEA Data Bank Computer Program Services to its member countries http://www.nea.fr/html/dbprog/. Additional information about Penelope is available on the Forum list archives http://www.nea.fr/lists/penelope.html .

 

AUXILIARY PROGRAM

PENGEOM2: Generation of random electron-photon showers in material systems consisting of homogeneous bodies limited by quadric surfaces.
 

2. CONTRIBUTORS

Universitat de Barcelona and Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya in Barcelona, Spain, and Universidad Nacional de Cordoba, Argentina, through the Nuclear Energy Agency Data Bank, Issy-les-Moulineaux, France.
 

3. CODING LANGUAGE AND COMPUTER

Fortran 77; DEC Alpha, Sun, and PC (C00682/MNYCP/02).
 

4. NATURE OF PROBLEM SOLVED

PENELOPE performs Monte Carlo simulation of electron-photon showers in arbitrary materials. Initially, it was devised to simulate the PENetration and Energy LOss of Positrons and Electrons in matter; photons were introduced later. The adopted scattering model gives a reliable description of radiation transport in the energy range from a few hundred eV to about 1GeV. PENELOPE generates random electron-photon showers in complex material structures consisting of any number of distinct homogeneous regions (bodies) with different compositions. The Penelope Forum list archives and other information can be accessed at http://www.nea.fr/lists/penelope.html.

The present version 2001 contains substantial changes and improvements to the previous versions 1996 and 2000. As for the physics, the model for electron/positron elastic scattering has been revised. Bremsstrahlung emission is now simulated using partial-wave data instead of analytical approximate formulae. Photoelectric absorption in K and L-shells is described from the corresponding partial cross sections. Fluorescence radiation from vacancies in K and L-shells is now followed. Refinements were also introduced in the electron/positron transport mechanics, mostly to account for the energy dependence of the mean free paths for hard events. The simulation routines have been re-programmed in a more structured (and readable) way, and new example MAIN programs have been written with a more flexible input and expanded output.
 

5. METHOD OF SOLUTION

The Monte Carlo method is used. A sufficiently large number of particle histories is simulated, and relevant quantities are obtained as averages.
 

6. RESTRICTIONS OR LIMITATIONS

Note that PENELOPE does not work for elements with atomic number Z>92. Electron and positron kinetic energies must be in the range from 100 eV to 1 GeV. Plural or multiple scattering conditions must be fulfilled, i.e. the number of both elastic and inelastic interactions in the material has to be larger than about about 10. Photon energies must be in the range from 100 eV (or the M-shell absorption edge, whichever is the largest) to 1 GeV. Photo-nuclear reactions are disregarded.
 

7. TYPICAL RUNNING TIME

The running time largely depends on the number of histories to be simulated, the kind of incident particle and its initial energy and the considered geometry.
 

8. COMPUTER HARDWARE REQUIREMENTS

Penelope runs on workstations and personal computers.
 

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran compiler is required on all systems to build problem-specific executables; therefore, no executables are included in the package. Penelope can be run on almost any operating system supporting a Fortran 77 compiler (Unix, MS-DOS, Windows95, Windows NT, ME, VMS, etc.). The code was tested at RSICC on a PC Pentium under WindowsME using GNU Fortran G77 v0.5.25.
 

10. REFERENCES

a: included in document:

F. Salvat, J.M. Fernandez-Varea E. Costa, and J. Sempau, "PENELOPE - A Code System for Monte Carlo Simulation of Electron and Photon Transport," Workshop Proceedings, Issy-les-Moulineaux, France, ISBN:92-64-18475-9 (November 2001).
 

b. background information:

F. Salvat and J.M. Fernandez-Varea, 'Semiempirical cross sections for the simulation of the energy loss of electrons and positrons in matter'. Nucl. Instrum. and Meth. B63 (1992) 255-269.

J.M. Fernandez-Varea, R. Mayol, J. Baro and F. Salvat, 'On the theory and simulation of multiple elastic scattering of electrons'. Nucl. Instrum. and Meth. B73 (1993) 447-473.

J.M. Fernandez-Varea, R. Mayol and F. Salvat, 'Cross sections for elastic scattering of fast electrons and positron by atoms'. Nucl. Instrum. and Meth. B82 (1993) 39-45.

T.M. Jenkins, W.R. Nelson and A. Rindi, eds., Monte Carlo Transport of Electrons and Photons (Plenum, New York, 1988). See, in particular, chapter 17 (Geometry Methods and Packages) by Nelson and Jenkins.

M.J. Berger and S.M. Seltzer, several chapters in Monte Carlo Transport of Electrons and Photons, eds. T.M. Jenkins, W.R. Nelson and A. Rindi (Plenum, New York, 1988).

J.A. Halbleib, R.P. Kensek, T.A. Mehlhorn, G.D. Valdez, S.M. Seltzer and M.J. Berger, Sandia National Laboratories Report SAND91-1634 (1992).

W.R. Nelson, H. Hirayama and D.W.O. Rogers, Stanford Linear Accelerator Center Report SLAC-265 (1985).

R. Brun, F. Bruyant, M. Maire, A.C. McPherson and P. Zanarini, CERN Report DD/EE/84{1 (1986).
 

11. CONTENTS OF CODE PACKAGE

Included are the referenced document in 10.a and a CD which contains source files, test case input files, data files and documentation written in a self-extracting compressed Windows file.
 

12. DATE OF ABSTRACT

May 2001, revised March 2002.
 

KEYWORDS: MONTE CARLO; BREMSSTRAHLUNG; HIGH ENERGY; GAMMA-RAY; POSITRON; WORKSTATION; MICROCOMPUTER