A study of the terrestrial and cosmic gamma-rays in Jordan

Natural terrestrial gamma and cosmic radiations dose rates in Jordan were measured during a period of three years in thirty four stations distributed over all Jordanian territories using the thermoluminescence dosimeter(TLD) Coso4:Tm. The average absorbed dose rates in air from terrestrial gamma and cosmic radiations were found to vary from(57 ±3;9) n Gy/hr in Assafi to (350 ± 14; 42) n Gy/hr in Manjam Alhisa. The mean dose rate due to terrestrial gamma radiations was found to be equal to (55 ± 2; 13) nGy/hr, and that due to cosmic radiations was calculated to be(35 ± 1;4) n Gy/hr. The annual effective dose equivalent from terrestrial and cosmic gamma radiations was found to be equal to(0.65±0.02; 0.12)mSv/year. It was found that the absorbed dose rate due to cosmic radiations in Jordan can be fitted by the formula, Dcosmic=27+5.2 h+1.86 h2 where h is the altitude reference to the Dead Sea measured in km. 19 refs., 17 figs., 6 tabs.(Author)