In situe and lab measurement of 137Cs for soil redistribution studies (Case study: Kachik basin of Golestan Province)

γ- ray specterometry of fallout radionuclides especially in case of soil redistribution was taken into acount by greate number of researchers around th world. These specterometry was done in lab or in-situe. Due to 137Cs importance in soil redistribution studies, its specterometry was conducted in reference area and three Sub-catchments of Kachik basin of Golestan province. For this, 132 soil samples collected from reference area and Agh emam Sub-catchment and their specterometry were done in lab. Mean of 137Cs activity for these areas were 14.30± 0.74 and 4.29± 0.25 Bqkg-1, respectively. For Testifier and Sample Sub-catchments, portable HPGe was used. Mean of 137Cs activity for these Sub-catchments were 7.04 ±4.74 and 6.72± 4.53 Bqkg-1 in turn. To compare in-situe and lab measurement, 120 samples for every measurement taken into account. Delta Activity for lab measurement was significantly lower than that in-situe measurement. While compared these two methods for 120 situations by portable HPGe and 120 samples measured in lab, results confirmed suitabielity of portable HPGe. Using portable HPGe, cost and time of getting results can be reduced by 2.08 and 6.25 times, respectively.