Assessment of Background Radiation Level of Gombe State Polytechnic Bajoga, Gombe State, Nigeria

This study assesses the background radiation level of Gombe State Polytechnic Bajoga, Gombe State in other to determine the effective dose of the area and compare the values obtained with maximum permissible dose limits (MPL). A total of twenty points across the institution were surveyed using a portable Geiger Muller LND 7223 radiation survey meter (GM Counter). At each measurement point, three readings in Count Per Minute (CPM) were taken with the Geiger Muller counter held at one meter above the ground and the average is taken as the mean Count Per Minute. The mean Counts Per Minute obtained were converted to Exposure rates in mR/hr, Absorbed Dose rate in nGy/hr and Annual effective doses in mSv/yr. The exposure rate ranges from 7.5μR/hr to 11.5 μR/hr with a mean value of 8.9R/hr. The highest value of 11.5 μR/hr was obtained at the Gate. The absorbed dose obtained ranges from 65. 45 nG/hr to 99 nGy/hr with mean of 77.56 nGy/hr with is slightly higher than the world average 55nGy/hr. The annual equivalent dose rate for indoor ranges from 0.459 to 0.322 with an average of 0.381 mSv/yr while the outdoor annual equivalent dose rate ranges between 0.122 to 0.080 mSv/yr. The mean annual effective dose rates for Indoor and Outdoor for this study are 0.381mSv/yr and 0.095 mSv/yr respectively. These values are lower than the internationally approved annual dose limits of 1mSv/yr for members of the public by International Commission on Radiation Protection [ICRP]. Hence, it is concluded that there are no significant risks from harmful radiation exposure in the study area.