Background: High level radiation areas have been
recognized on various parts of the earth. Mahallat hot
spring region is one of these areas. Study of exposure
in these areas can be helpful in investigating the
effects of ionizing radiation. Internal and external
exposure to the staff was studied. Materials and
Methods: Used materials and instruments include:
RSS-112 ionizing chamber for environmental gamma
rays measurement, pure germanium detector for
measuring radioactive elements in the ground, liquid
scintillation counter for measuring 222Rn gas
concentration in water samples, Bubbler chamber and
Locus cells for 226Ra concentration measurements as
emanation method and Alfa guard detector for 222Rn
concentration measurements. Results: Considering
stay period of the studied groups in indoor and
outdoor environment, calculated annual external
effective dose for staff has been 514.8 ± 22.7 μSv.
Annual internal effective doses for staff in outdoor and
indoor environment has been 21.1 mSv. Annual
internal effective dose for staff due to drinking water
has been 32 μSv. Conclusion: Measurements
showed that more than 90% of the received dose in
the studied groups was due to inhalation of Radon
gas. External and internal effective dose for the staff
was 21.6 mSv. Considering these results Mahallat hot
spring region is a high level natural radiation area
(HLNRA). Iran. J. Radiat. Res., 2008 6 (1): 13-18
Tavakoli M, Fallah Mohammadi G, Fallah Mohammadi Z, Shaneh Z. Staff exposure rate in Mahallat hot spring region. Int J Radiat Res 2008; 6 (1) :13-18 URL: http://ijrr.com/article-1-374-en.html