EXAMINATION OF NATURAL RAD IOACTIVITY IN BUILDING MATERIAL IN KATSINA STATE USING GAMMA RAY SPECTROSCOPY ( A CASE STUDY OF CEMENT BLOCK)

Abstract

T wenty Concrete Blocks from (20) different Local Governments in Katsina state was measured using Gamma Ray Spectroscopy with NaI (TL) detector. Three naturally Occurring Radionuclides and their activity concentrations were determined, are 40 K 226 Ra, and 232 Th. Their activity Concentrations ranges from 40 K 46.11 ± 826.59 to 46.11 ± 8.55 Bq/kg, ( 226 Ra) ranged from10.19 ± 2.43Bq/kg to 75.09 ± 4.98 Bq/kg and ( 232 Th) ranged from 2.77 ± 9.59Bq/kg to 123.49 ± 9.35 Bq/kg respectively. The highest value also determined from 40 K was (826.59 ± 4.82Bq/kg), the highest value of 226 Ra was 75.09 ± 4.98Bq/kg , the highest value for ( 232 Th) is 123.49 ± 9.35 Bq/kg respectively. The Radium Equivalent mean value was obtained fr om the measurement ranged from (34.8 ± 1.59 to 411.26nGT/h), The absorbed dose rate in air with its mean value was obtained, ranges from (147.16 ± 3.55nGy/h). The limit set in the OECD report (370Bq/kg) and UNSCEAR, 2000 (24 to 160nGy/h). The annual effect ive dose obtained, ranges from 0.04 ± 0.001 to 0.20 ± 0.0001mSv/y, with mean value 0.187 ± 0.0005mSv/y. Recommended limit 0.460 mSv/y set by ICRP, 2007 for terrestrial radiation. The evident that the Results give lower value when compared with 1mSv/y for Public exposure (ICRP, 2007).