Abstract
In this study, a Geiger Muller ionization counter has been used to investigate the variation of background radiation dose level with time in a typical x-ray machine room and its environment. This is to monitor the effect of x-ray exposure on the background ionizing radiation level. The results showed that within a period of 3 hours, the cumulative background radiation dose in the x-ray room grew from s s Gy to around 84 . 90 ́ 10 - 10 - an initial level of 38 . 78 ́ Gy compared with nearby rooms where the s cumulative radiation grew from almost zero to a maximum value of about 46 . 9 ́ Gy within the 10 - same period. It was observed that after a radiation exposure from the machine, the background s radiation dose rate took about 25 minutes to decay from a maximum level of around 45 ́ Gy/hr to 10 - - s 17 . 47 ́ 10 the background level about Gy/hr which was found to be higher than the background dose rates in other nearby locations. While the dose rate in the x-ray machine room was higher than the s 10 - maximum dose limit of 12 ́ Gy/hr recommended for members of the public by the International Committee for Radiation Protection (ICRP), the dose rates in the other locations studied in the neighbourhood of the x-ray machine were within the limit.