Experimental Studies on Gamma-Ray Dose Rates from a ⁶⁰Co Cylindrical Source

Gamma-ray dose rates from a ⁶⁰Co cylindrical source were obtained experimentally in the radial direction at the half-height of the source. The concept of the dose buildup factor was introduced for a volume source. The dose buildup factor for a cylindrical source, which is represented as a function of the distance between source and detection point, has a value of about five at the point nearest to the source surface. The factor then decreases rapidly, passes through a minimum value, and approaches a constant value. These features were analyzed experimentally with a line and a disk source. An empirical formula for the dose buildup factor is proposed which agrees with the experimental values to within about ± 15%.