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CCC-0581 FOTELP/EM.

FOTELP/EM, 3-D Monte-Carlo Photon, Electron, Positron Transport in Magnetic Field

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1. NAME OR DESIGNATION OF PROGRAM:  FOTELP/EM.
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2. COMPUTERS
To submit a request, click below on the link of the version you wish to order. Only liaison officers are authorised to submit online requests. Rules for requesters are available here.

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Machines used:

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3. DESCRIPTION OF PROGRAM OR FUNCTION

FOTELP computes the transport of photons, electrons and positrons through three-dimensional material and sources geometry by Monte Carlo, with or without the presence of macroscopic electric and magnetic fields. The November 1997 release of FOTELP-EM is a complete replacement of the FOTELP code, which was packaged in January 1991.
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4. METHODS

Physical rigour is maximised by employing the available cross sections and sampling distributions and the most complete physical model for describing the transport and production of the photon/electron/positron cascade from 20.0 MeV down to 1.0 kev. FOTELP/EM is developed for photon, electron and positron numerical experiments by Monte Carlo for dosimetry, radiation damage, radiation therapy and other applications.
  For photon history the trajectory is generated by following it from scattering to scattering using corresponding inverse distribution between collision, types of target, types of collisions, types of secondaries, their energy and scattering angles. Photon interactions are: photoelectric absorption, incoherent scattering, pair production, and coherent scattering. The secondary photons which are followed include bremsstrahlung and positron-electron annihilation radiation.
  The condensed history Monte Carlo method (Berger 1963) is used for the electron and positron transport simulation. During a history the particles lose energy in collisions, and the secondary particles are generated on the step according to the probabilities of their occurrence. Electron (positron) energy loss is through inelastic electron-electron (e-,e-) and positron-electron (e+,e-) collisions and bremsstrahlung generation. The fluctuation of energy loss (straggling) is included according to the Landau's or Blunk-Westphal distributions with 9 gaussians. The secondary electrons which follow history of particles include knock-on, pair Compton and photoelectric electrons. The secondary positrons which follow pair production are included, too. With atomic data, the electron and positron Monte Carlo simulation is broadened to treat atomic ion relaxation after photoeffect and impact ionization. In the presence of electric and/or magnetic fields, FOTELP/EM estimates trajectory of charge particles on the step in the actual zone. Flexibility of the codespermits them to be tailored to specific applications and allows the capabilities of the codes to be extended to more complex applications.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

For PC with 16MB RAM memory, number of geometric zones must be less than 20.
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6. TYPICAL RUNNING TIME

For the cross-section generating, probabilities and inverse distributions calculation program FEDPAT, on a PC processor of 75 MHz with base memory 640 Kbyte and extended memory 16 Mbyte, execution time is about one minute for one materials.
The 10,000 history sample problem simulation with program FOTELP for two material zones requires about 10 minutes on the same PC. The run time for similar problems with presence of electric and magnetic fields on the same PC would be about five times longer.
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7. UNUSUAL FEATURES
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8. RELATED OR AUXILIARY PROGRAMS

EPSKL:    Energy Scaling Program
RTZAK:    Gaussian Integration of Cross Sections
SIGAMA:   Photon Cross Section Calculation
AVERZ:    Bremsstrahlung's Probabilities Calculation
MOLVER:   Moliere Inverse Distribution Calculation
VERPOZEL: Probability For Electron and Positron
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9. STATUS

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10. REFERENCES

- Ilic, R.D.
  Numerical Experiments with Photons, Electrons and
  Positrons by Monte Marlo techniques
  "Vinca" report 1609 (1996)
- Ilic, R.D.
  Computational Simulation of Electron Penetration Through         Material by Monte Carlo Techniques: SANU.DOC
  In 100 Years Since Discovery of Electron
  (in manuscript) (1996)
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11. HARDWARE REQUIREMENTS

FOTELP is operable on the PC or VAX; a minimum of 8 megabytes of hard disk is needed.
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12. PROGRAMMING LANGUAGE(S) USED

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13. SOFTWARE REQUIREMENTS

A FORTRAN 77 compiler is required to recreate executables. The FORTRAN/EM package can be installed and run on PC with at least /8MB/66MHz/ with either MS-DOS 6 or WINDOWS 3.1 and higher. The FORTRAN PowerStation can be used to compile the source. On a Micron PII/266 running Windows95, the DEC Visual Fortran 90 compiler was used to create the executables included in the package.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS
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15. NAME AND ESTABLISHMENT OF AUTHORS

Contributed by:
  Radiation Safety Information                                         
  Oak Ridge National Laboratory
  Oak Ridge, Tennessee, U. S. A.

Developed by:   
  Institute of Nuclear Sciences "Vinca"
  Nuclear Engineering Laboratory "NET",
  Beograd, Yugoslavia
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16. MATERIAL AVAILABLE
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17. CATEGORIES

Keywords: Monte Carlo method, charged particles, computers, electrons, magnetic fields, positrons, three-dimensional, transport.