Variation of environmental neutron flux with altitude and depth of both water and soil

Variation of environmental neutron flux with altitude and depth of both water and soil 1 first-author 2 3 2 Low Level Radioactivity Laboratory, Kanazawa University, Wake Tatsunokuchi, Ishikawa 923-1224, Japan; Low Level Radioactivity Laboratory, Kanazawa University, Wake Tatsunokuchi, Ishikawa 923-1224, Japan; Physics Department, Faculty of Science, South Valley University, Kena, Egypt; Physics Department, Faculty of Science, South Valley University, Kena, Egypt; Physics Department, Faculty of Science, Assiut University, Assiut, Egypt Physics Department, Faculty of Science, Assiut University, Assiut, Egypt Applying the extreme low-level γ-ray spectroscopic analysis the environmental neutron flux is measured using different moderator construction and environment through the reaction 197 Au (n, γ) 198 Au. The contribution of thermal and resonance neutrons is separated using the cadmium difference technique, while fast neutrons are measured by the paraffin moderator. The results of altitude dependence of the neutron flux are discussed. The thermal neutron flux near the surface of sea water is less than its value at 100 cm over ground near sea water, while the value over the surfaces of fresh water is higher than that near the surface of sea water. Also the thermal neutron flux at 5 cm soil depth increases, then decreases to its original value at 10 cm depth and still constant until 25 cm, then decreases rapidly to reach 27% of its original value at 60 cm depth. The soil compositions, corresponding neutron temperatures and effective absorption cross sections of earth are the most effective factors on the equilibrium region of thermal neutrons in the ground. Extreme low-level γg-ray spectroscopy Environmental neutron flux Gold activation References Kodama M , Kawasaki S , Imai T et al . Anomalous atmospheric attenuation of cosmi-ray-produced neutrons near the earth's surface , in: U.S Department of Energy , Natural Radiation Environment III , 1980 , 2 : 882 Anomalous atmospheric attenuation of cosmi-ray-produced neutrons near the earth's surface Hewitt J E , Hughes L , McCaslin J B et al . Exposure to cosmic-ray neutrons at commercial jet aircraft altitudes , in: U.S Department of Energy, Natural Radiation Environment III , 1980 , 2 : 855 Exposure to cosmic-ray neutrons at commercial jet aircraft altitudes Nakamura T , Uwamino Y , Ohkubo T et al . Health Phys , 1987 , 53 ( 5 ): 509 Health Phys Moraal H , Potgieter M S , Stoker P H et al . J Geophys Res , 1989 , 94 ( A2 ): 1459 J Geophys Res Wordel R , Mouchel D , Altzitzoglou T et al . Nucl Instrum Meth Phys Res , 1996 , A369 : 557 Nucl Instrum Meth Phys Res Chung C , Chen C Y , Kung C H . Appl Radiat Isot , 1997 , 49 ( 4 ): 415 Appl Radiat Isot Chen C Y , Chung C . Nucl Instrum Meth Phys Res , 1997 , A395 : 195 Nucl Instrum Meth Phys Res O'Sullivan D , Zhou D , Heinrich W et al . Rad Meas , 31 : 579 Rad Meas Heinrich W . Physics of cosmic radiation fields , Int conf on cosmic radiation and air crew exposure , Dublin , 1998 Physics of cosmic radiation fields Reitz G . Rad Prot Dos , 1991 , 48 : 5 Rad Prot Dos O'Brien K , Sandmeier H A , Hansen G E et al . J Geophys Res , 1978 , 83 ( A1 ): 114 J Geophys Res Yamashita M , Stephenson L D , Patterson H W . J Geophys Res , 1966 , 71 ( 16 ): 3817 J Geophys Res Dep L , Elmore D , Lipschutz M et al . Nucl Instrum Meth Phys Res , 1994 , B92 : 301 Nucl Instrum Meth Phys Res Sazonova T E , Zanevsky A V , Kharitonov I A et al . Appl Radiat Isot , 1998 , 49 ( 9-11 ): 1185 Appl Radiat Isot Komura K , Yousef A M , Ahmed N K et al . Measurement of environmental neutrons by activation of gold , Abstract of the 42nd Symp. of Radiation Research of Japan , Sept. 1-3, 1999 , Hiroshima , 1-E-11 , 88 Measurement of environmental neutrons by activation of gold Emmett M B . The Monte Carlo Radiation Transport Code System , ORNL-4972 , 1975 The Monte Carlo Radiation Transport Code System Tommasino L . Radiat Prot Dosim , 1999 , 86 ( 4 ): 297 Radiat Prot Dosim McAulay I R , Bartlett D T , Dietze G et al . Exposure of air crew to cosmic radiation, A report of EURADOS working group 11 , European Commission , 1997 Exposure of air crew to cosmic radiation, A report of EURADOS working group 11 Chung C , Chen C Y . J Geophys Res , 1997 , 102 ( D25 ): 29827 J Geophys Res Hess W N , Canfield E H , Lingenfelter R E . J Geophys Res , 1961 , 66 ( 3 ): 665 J Geophys Res Hajnal F , McLaughlin J E , Weinstein M S et al . USAEC report HASL-241 , 1971 USAEC report HASL-241 Hewitt J E , Hughes L , Baum J W et al . Health Phys , 1978 , 34 : 375 Health Phys Bethe H A , Korff S A , Placzek G . Phys Rev , 1940 , 57 : 573 Phys Rev Swetnick M J . Phys Rev , 1954 , 95 : 793 Phys Rev Edge R D . Nucl Phys , 1959 , 12 : 182 Nucl Phys Hendrick L D , Edge R D . Phys Rev , 1966 , 145 ( 4 ): 1023 Phys Rev X125,TL816 2003-09-26 2004-08-01 2021-01-19 2004 Nuclear Science and Techniques 04 15