NATURAL RADIOACTIVITY OF BASEMENT YOUNGER GRANITE ROCKS FROM THE EASTERN DESERT

The present work deals with a study of natural radioactivity of variou s samples of granite rocks from the Umm Gidri area located in North Ea stern Desert. In this area, about 300 km apart from El-Minia, some geo logical investigations were carried out. Several samples of the baseme nt rocks (of the Precambrian Age) 5 m subsurface were obtained from di fferent locations. Suitable samples were prepared for natural gamma ra y measurements using a 5 x 5 in. Nal(Tl) scintillation spectrometer. Q ualitative analysis of natural gamma radiations from the present sampl es have revealed the presence of the radioisotopes: K-40, Bi-214, Tl-2 08 and Ac-228 in meaningful concentrations. These results are thought to correlate with the findings of a recent trace element geological as say done at the same area, and it would be of help in monitoring and a ssessing the national background radiation levels.