Materials with high atomic numbers favor the occurrence of the photoelectric effect when they are irradiated with gamma rays. Therefore, the photoelectric effects of metal implants within the target regions in Gamma Knife Radiosurgery are worth studying. In the present work, Monte Carlo simulations using EGS4 were employed to investigate the resulting dose enhancements. A dose enhancement as hi...

We present our plans for a Monte-Carlo code simulating all possible combinations of (electromagnetic) interactions between colliding electron, positron, and both high-energy and l~er photon beams, based on the ABEL code for beam-beam interaction. The implementation and first results for the laser-e– interaction are described. *Work supported by the Department of Energy contract DE-AC-76SFO0515 ...

The dose distribution inside the Gamma Cobalt irradiation therapy unit at Egyptian Atomic Energy Authority (EAEA) was determined both experimentally and theoretically. MCNP computer code, based on Monte Carlo method, was used to model the unit and calculate the dose distributions in both normal and emergency situation of the unit. The dose distribution inside the unit was also measured during t...

In view of assessing natural radioactivity with on-site quantitative gamma spectrometry, efficiency calibration of NaI(Tl) detectors is investigated. A calibration based on Monte Carlo simulation of detector response is proposed, to render reliable quantitative analysis practicable in field campaigns. The method is developed with reference to contact geometry, in which measurements are taken pl...

A Monte Carlo technique for modeling background in space-based gamma-ray telescopes has been developed. The major background components included in this modeling technique are the diffuse cosmic gamma-ray flux, the Earth's atmospheric flux, the decay of nuclei produced by spallation of cosmic rays, trapped protons and their secondaries, the decay of nuclei produced by neutron capture, and the d...