Simulation of environmental dose distribution of nuclear gauge device MC-1DR by MCNPX code

In this study, distribution of dose rate around the nuclear gauge device MC-1DR which located in shahrekord university was simulated by MCNPX code and was compared whit the measured values. Due to the asymmetry of device and neutron and gamma source positions, the dose rates were determined at a distance of 5, 30 and 100 cm in different directions. Base on the complex geometry of the inside of device, there are discripency between measured and simulated results in the some points. In general, the values show when the gamma source is positioned in safe mode. The maximum and minimum of dose rate are in below and back of the device. Also, in the left side neutron dose and in the right side gamma dose is greatest. Finally, for safe operating one hour is at most recommended at a distance of 1m in compare with standard threshhold, 12mrem per day.