Monte Carlo Simulation ofScattered Radiation of Free-Field Geometries Gama Reference Radiation Field

Reference radiation filedproduced by isotope source is necessary for calibration of radiation dosemeter. Scattered dose is an important characteristic in the reference radiationfield.How to reduce the scattered dose is an important research of radiationmetrology.Monte Carlo method was used to obtain the dose distribution of openand closed geometries free-field gamma reference radiation field, calculatedthe scattered dose. The calculation was tested by the results acquired in theRadiation Metrology Center in order to find a Monte Carlo method to study thefree-field reference radiation field, the photons scattered in floor, walls,air etc. was also calculated.In addition, the conclusion of this study can alsodo good to the design and construct of the free-field radiation field.