Measurement of Background Gamma Radiation Levels at Two Tertiary Institutions in Minna, Nigeria

Abstract

An in-situ measurement of the background radiation level was carried out at the vicinity of three campuses of two major tertiary institutions in Minna. A portable Geiger-Mueller tube-based environmental radiation dosimeter was used for the measurement. A total of 34 point was surveyed across the three institutions for background environmental radiation. The dose rate range obtained are: at the Niger State College of Education Minna (NCM), the dose rate varies from 0.125 µSv/hr to 0.171µSv/hr; at the Federal University of Technology Bosso Campus (FUTB) it wass between 0.152 µSv/hr and 0.184 µSv/hr; and at the Federal University of Technology Gidan-Kwano campus FUTG it was between 0.137 µSv/hr and 0.184 µSv/hr. In all the 34 points surveyed the mean dose rate was 0.154 µSv/hr with a standard deviation of 0.017 µSv/hr. Generally, the dose rate level in each of the institutions surveyed are comparable to one another and could simply be attributed to natural sources. The average annual effective dose obtained from this study is 0.189 mSv/annum which is still less than the recommended limit of 1mSv/annum by International Commission on Radiation Protection [ICRP] for non occupational population exposure. @ JASEM Radiation from many sources is omnipresent on the earth surface, consequently man is continuously irradiated. The basic difference between ionizing (nuclear) radiation and other common types of radiation in the environment such as heat is that it possesses sufficient energy to cause ionization. In water of which cell are largely composed, ionization can lead to molecular changes and to the formation of chemical species of a type which are damaging to the chromosome material. Ionizing radiation injury is dependent on a number of factors including: The nature (alpha (α), betta (β), and gamma (γ)) and energy of the radiation, the dose, time of exposure, homogeneity of dose and shielding. When the dose and dose rate is within the accepted level, the effect of radiation is small and most time no effect is noticed, although the effect