Physical rigor is maximized by employing the best available cross sections and high speed routines for random values sampling from their distributions, and the most complete physical model for describing the transport and production of the photon/electron/positron cascade from 100.0 MeV down to 1.0 keV. FOTELP-2K6 is developed for numerical experiments by Monte Carlo techniques for dosimetry, radiation damage, radiation therapy and other actual applications of these particles.
For the 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 coherent scattering, incoherent scattering, photoelectric absorption and pair production. Doppler broadening in Compton scattering are taken. The histories of secondary photons include bremsstrahlung and positron-electron annihilation radiation.
The condensed history Monte Carlo method 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 for 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 production, 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 photo-effect and impact ionization. Flexibility of the codes permits them to be tailored to specific applications and allows the capabilities of the codes to be extended to more complex applications, especially in radiotherapy in voxelized geometry using CT data (http://www.vin.bg.ac.yu/~rasa/hopa.htm).