In the present study, a gamma background radiation dose at indoor and outdoor for selected
schools was determined in the north section at An-NAJAF governorate, Iraq. Measurements were
performed using a portable dosimeter survey “Inspector Alert model RAP RS1, S.E. international,
Inc, USA”. Average of indoor and outdoor mean rate dose was ranged from (307.543 - 66.744nGy/
h) respectively, Amount of minimum and maximum mean dose were ranged from (269.808 ± 63.331
and 55.188± 15.832 nGy/h) and (343.398± 40.054 and 73.584±10.013 nGy/h) successively. Annual
Effective Dose indoor and outdoor were enumerated between (0.33 and 0.27 mSv/y), (0.42 and 0.36
mSv/y) respectively, while the average of Annual Effective Dose ranged between (0.376 – 0.34). So,
according to the results of the area under study, this would not pose a significant risk to human
beingswhich is recommended by UNSCEAR (2000).