The Dose Distribution Inside the Irradiation Chamber of the Gamma Cell 220 at KACST Using MCNP4B

Abstract

In the irradiation chamber of gamma cell-220 at KACST the dose distribution must be determined. The determination of this dose distribution gives an idea a bout the amount of the dose in any place inside the irradiation chamber which helps also to find the average dose given to any object that needs to be irradiated. The Monte Carlo N Particle code (MCNP4B)(1) was used to estimate the dose distribution inside the irradiation chamber. Point detectors were used in this simulation. The code was run for sufficient numbers of history which shows a symmetrical distribution around the axis of the irradiation chamber, and the errors is less than 5%. The dose map shows that the dose increases as it is calculated from the center of the chamber to the chamber perimeter edge, and it decreases as moving to the top or the bottom of the chamber. The calculation was compared with a measurement, which was done by Dr. Abdelrehim. A good agreement between the calculation and the measurement was obtained.