Variations of exposure rate as a function of position and energy using thermoluminescence dosimeters

The exposure rate at different positions of various combinations of horizontal and vertical distances around van de Graaff accelerator at King Saudi University as a function of energy using thermoluminescence dosimeters has been investigated. It has been observed that the exposure rate is heavily position-energy dependent and in fact exhibit symmetrical unimodel trend against positions. Thus, low dose response is experienced at extreme positions as compared to the response at the central position. It has been also noticed that overall response for energy level 1 MeV for 9 positions is invariably lower than overall response for energy level 1.5 MeV and even much lower than energy level 2 MeV. It has also been observed that some of the combinations of variable parameters are more significant than others. Thus, it is believed that exposure rate is energy as well as positional dependent. A linear model is proposed and the strong agreement between the experimental and estimated values establish the suitability of this model.2 tab.,3 fig