Uniformity of dose rate distribution in a cage type gamma-source

A cage type gamma-source is used for the uniform gamma irradiation of materials. However, the uniformity is disturbed around the linear gamma-sources. The spatial distribution of dose rate was calculated, taking the cylindrical arrangement of linear gamma-sources into account. The considered cage is a cylindrical one, and the shape of sources are pencil type. The results of calculation showed that the dose distribution in the direction parallel to the cage axis was uniform in the spatial region upto 30 mm from the center axis. In the region outside the central part, the distribution depends on the nearest source. The distribution in the radial direction from the center axis was also calculated. As a final result, it can be said that the dose distribution is uniform within the space of 50 percent in radial direction and 60 percent in axial direction. (Kato, T.)