Research Journal of Recent Sciences ______ ______________________________ ______ ____ ___ ISSN 2277 - 2502 Vol. 2 ( 3 ), 7 - 13 , March (201 3 ) Res. J. Recent Sci. International Science Congress Association 7 Study of Attenuation Coefficient Measurements in Buffalo Milk at Gamma Energy 662 keV Chaudhari Laxman 1 and Girase Sanjeev B. 2 1 Nuclear Research Laboratory, Department of Physics, Nowrosjee Wadia College, Pune - 411001, MS, INDIA 2 Department of Physics, S. V.S’S Dadasaheb Rawal Collee, Dondaicha Dist. Dhule - 425408, MS, INDIA Available online at: www.isca.in Received 2 5 th June 2012 , revised 16 th November 2012 , accepted 1 st December 2012 Abstract Mass attenuation coeffic ients of milk sample have been studied by using gamma radiation at energy 662keV. The results have been presented in a graphical form. The graph of path length (cm) V/s particle intensity shows linearity. The points are fitted with least square method. T he slope there graphs gives the value of the liner absorption coefficient. The density of milk sample at different concentrations V/s attenuation coefficients shows that attenuation coefficients decreases exponentially with increasing the density and confi rms the interaction of gamma radiations with various concentrations of milk sample The mass attenuation coefficient usually depends upon the density and the concentration of the milk samples. Exponential decay was observed. This validates the gamma abso rption law. Keywords: Attenuation coefficient, gamma ray energy sources, gamma ray spectrometer, NaI (Tl) detector, etc Introduction The study of interaction of gamma radiations with the materials of common and industrial use, as well as of biological and commercial importance has become major area of interest in the field of radiation science. For a scientific study of interaction of radiation with matter a proper characterization and assessment of penetration and diffusion of gamma rays in the externa l medium is necessary. The mass attenuation coefficient usually depends upon the energy of radiations and nature of the material. For characterization the penetration and diffusion of gamma radiation in any medium, the roll of attenuation coefficient is ve ry important. An extensive data on mass attenuation coefficients of gamma rays in compound and mixtures of dosimetric interest have been studied by 1 in the energy range of 1 kev to 20 Mev. An updated version of attenuation coefficients for elements having atomic number from 1 - 92 and for 48 additional substances have been compiled by 2 . Other scientists 3 - 7 . The reports on attenuation coefficients measured by researchers reported 8 - 24 for different energies for various samples in solid as well as liquid. In view of the importance of the study of gamma attenuation properties of materials and its various applications in science, technology, agriculture and human health, we have embarked on a study of the absorption properties of buffalo milk sample contains mi xture of microelements. The absorption coefficient of milk is dependent on its content and gamma - ray energy. This work describes a study of content dependence on measurements of attenuation of gamma - radiation at gamma - ray energy 662 keV of milk sample. T he attenuation of gamma rays expressed as: I= I o exp ( -  x) (1) Where I o is the number of particles of radiation counted during a certain time duration without any absorber, I is the number counted during the same time with a thickness x o f absorber between the source of radiation and the detector, and   is the linear absorption coefficient. This equation may be cast into the linear form, log I = log I o -  x i.e.  x= log (I o/ I) i.e.  = (1/x) log(I o/ I) (2) The mass absorption coefficient of milk  m defined as,  m =  /ρ (3) Where,  m is the mass attenuation coefficient and  is the density of milk sample. The unit of  is cm - 1 and that of  m is cm 2 /gm. Material and Methods The experimental arrangement is as shown in fig ure - 1. A cylindrical glass container of internal diameter 2.9 cm placed in between detector and source having nominal activity 3.26  Ci. The collimated beam of gamma source and cylinder kept in a stand. The assembly was placed in lead castle. The distance between detector and source was 18.3 cm. The transmitted and scattered gamma rays were detected using USB - MCA along with external NaI (Tl) detector. First, the cylinder was kept empty keeping acquisition time 600 sec and readings were taken for gamma rays of a particular energy and noted as I o . Research Journal of Recent Sciences ______ _ _ _______________________________ ______________ _ ________ ISSN 2277 - 2502 Vol. 2 ( 3 ), 7 - 13 , March (201 3 ) Res. J. Recent Sci. International Science Congress Association 8 Thereafter, the path length(x) of milk sample varies by path length 1 to 10 cm respectively and readings were taken as I. Same procedure used for each samples with concentrations by adding water in the milk and pr epared for 10%, 20%, 30%,……..100%. The NaI (Tl) cystal was used as detecto in conjunction with counter circuits. The whole system enclosed in a lead castle. Results and Discussion The concentration of milk samples Vs path lengths are shown in tables 1 t o 5. Linear attenuation coefficients Vs concentration of milk samples by using gamma source Cs - 137 in shown in table 6 . Experimental values of number of particles of radiation without absorber (I o ) per number of particles of radiation counted with absorb er (I) were linearly increased with increasing path length in cm as shown in graphs. The slope of the graphs ( f igures 2 - 11) gives the value of the linear absorption coefficient. Figure - 1 Table - 1 Concentration of milk sample 10% and 20% Milk Concen tration : 10 % Initial Counts (I o ) = 161922 /600 sec) Milk Concentration : 20 % Initial Counts (I o ) = 160884/ 600 sec) Path length (cm) No. of counts I / 600 Sec. I o /I log (I o /I ) No. of counts I / 600 sec I o /I log (I o /I ) 1 154654 1.04699 0.0199 4 155554 1.034265 0.014632 2 149352 1.08416 0.03509 148376 1.084299 0.035149 3 144403 1.12132 0.04972 143326 1.122504 0.050188 4 138016 1.17321 0.06937 137298 1.171787 0.068849 5 132171 1.22509 0.08816 130426 1.233527 0.091149 6 123862 1.30727 0.11636 121944 1.319327 0.120352 7 114625 1.41262 0.15002 114100 1.410026 0.149227 8 108625 1.49065 0.17337 109539 1.468737 0.166944 9 102807 1.57500 0.19728 98280 1.636996 0.214048 10 92010 1.75983 0.24547 91998 1.748777 0.242734 Research Journal of Recent Sciences ______ _ _ _______________________________ ______________ _ ________ ISSN 2277 - 2502 Vol. 2 ( 3 ), 7 - 13 , March (201 3 ) Res. J. Recent Sci. International Science Congress Association 9 Table – 2 Concentration of m ilk sample 30% and 40% Milk Concentration : 30 % Initial Counts (I o ) = 160799 / 600 sec Milk Concentration : 40 % Initial Counts (I o ) = 160331 / 600 sec Path length (cm) No. of counts I / 600 Sec. I o /I log (I o /I ) No. of counts I / 600 sec I o /I log ( I o /I ) 1 154151 1.04312 0.01833 155423 1.03157 0.01350 2 149573 1.07505 0.03143 149740 1.07072 0.02967 3 143850 1.11782 0.04837 143577 1.11668 0.04793 4 137519 1.16928 0.06792 139233 1.15153 0.06127 5 130183 1.23517 0.09172 128730 1.24548 0.09533 6 123109 1.30615 0.11599 124501 1.287788 0.10984 7 114997 1.39828 0.14559 116685 1.37404 0.13800 8 107712 1.49286 0.17401 106276 1.50862 0.17858 9 98782 1.62781 0.21160 101726 1.57610 0.19758 10 90482 1.77713 0.24972 91872 1.74515 0.2418 Table - 3 Concen tration of milk sample 50% and 60% Milk Concentration : 50 % Initial Counts (I o ) =160677 / 600 sec Milk Concentration : 60 % Initial Counts (I o ) = 159649 / 600 sec Path length (cm) No. of counts I / 600 Sec. I o /I log (I o /I ) No. of counts I / 600 sec I o /I log (I o /I ) 1 154217 1.04188 0.01782 155048 1.02967 0.01270 2 149221 1.07677 0.03212 149776 1.06591 0.02772 3 144154 1.11462 0.04712 142714 1.11866 0.04869 4 136921 1.17350 0.06948 135868 1.17503 0.07004 5 130437 1.23183 0.09055 128526 1.24215 0.09417 6 123083 1.30543 0.11575 120955 1.31990 0.12054 7 115623 1.38966 0.14290 115082 1.38726 0.14215 8 109188 1.47156 0.16777 108105 1.47679 0.16932 9 97616 1.64601 0.21643 100814 1.58359 0.19964 10 93032 1.72711 0.23732 94840 1.68335 0.22617 Tab le - 4 Concentration of milk sample 70% and 80% Milk Concentration : 70 % Initial Counts (I o ) =157285 / 600 sec Milk Concentration :80 % Initial Counts (I o ) = 160885/ 600 sec Path length (cm) No. of counts I / 600 Sec. I o /I log (I o /I ) No. of counts I / 600 sec I o /I log (I o /I ) 1 154513 1.017940238 0.00772 156566 1.0275 0.01181 2 149714 1.050569753 0.02142 150224 1.07096 0.02977 3 142250 1.1056942 0.04363 146485 1.09830 0.04072 4 136928 1.148669374 0.06019 135908 1.18377 0.07327 5 128759 1.22154567 8 0.08690 132142 1.21751 0.08547 6 122724 1.281615658 0.10775 124088 1.29653 0.1127 7 116234 1.353175491 0.13135 117054 1.37445 0.13812 8 106132 1.481975276 0.17084 107991 1.48980 0.17312 9 97390 1.61500154 0.20817 99353 1.61932 0.2093 10 91492 1.7191 12054 0.23530 91445 1.75936 0.24535 Research Journal of Recent Sciences ______ _ _ _______________________________ ______________ _ ________ ISSN 2277 - 2502 Vol. 2 ( 3 ), 7 - 13 , March (201 3 ) Res. J. Recent Sci. International Science Congress Association 10 Table - 5 Concentration of milk sample 90% and 100% Milk Concentration: 90 % Initial Counts (I o ) = 161246 /600 sec) Milk Concentration : 100 % Initial Counts (I o ) = 161303/ 600 sec) Path length (cm) No. of counts I / 6 00 Sec. I o /I log (I o /I ) No. of counts I / 600 sec I o /I log (I o /I ) 1 157963 1.02078 0.00893 157410 1.02473 0.01061 s 2 151201 1.06643 0.02793 151359 1.06569 0.02763 3 145634 1.10720 0.04422 146192 1.10336 0.04271 4 140437 1.14817 0.06000 139085 1.15974 0.0643 5 131900 1.22248 0.08724 132345 1.21880 0.08593 6 124598 1.29412 0.11197 122994 1.31147 0.11775 7 116443 1.38476 0.14137 118153 1.36520 0.13519 8 105809 1.52393 0.18290 106204 1.51880 0.18150 9 100306 1.60754 0.20616 99392 1.62289 0.210 29 10 91269 1.76671 0.24716 70992 2.27212 0.35643 Table - 6 Linear attenuation coefficient V/s Concentration at Cs - 137 Concentration % Density, ρ (gm/cc) Linear absorption Coefficient (cm - 1 ) 10 0.9971715 0.02457 20 1.0050593 0.02521 30 1.0082463 0.02563 40 1.0118715 0.02502 50 1.0239756 0.02494 60 1.0258599 0.02406 70 1.0276641 0.02561 80 1.0304305 0.02571 90 1.0323149 0.02639 100 1.034482759 0.0323 The p ath Length v/s Ln (Io/I) are as shown in the following figures : Figure - 2 Path Length v/s Ln (Io/I) Figure – 3 Path Length v/s Ln (Io/I) Research Journal of Recent Sciences ______ _ _ _______________________________ ______________ _ ________ ISSN 2277 - 2502 Vol. 2 ( 3 ), 7 - 13 , March (201 3 ) Res. J. Recent Sci. International Science Congress Association 11 Figure – 4 Path Length v/s Ln (Io/I) Figure – 5 Path Length v/s Ln (Io/I) , Figure – 6 Path Length v/s Ln (Io/I) Figure – 7 Path Length v/s Ln (Io/I) Figure – 8 Path Length v/s Ln (Io/I) Figure – 9 Path Length v/s Ln (Io/I) Research Journal of Recent Sciences ______ _ _ _______________________________ ______________ _ ________ ISSN 2277 - 2502 Vol. 2 ( 3 ), 7 - 13 , March (201 3 ) Res. J. Recent Sci. International Science Congress Association 12 Figure – 10 Path Length v/s Ln (Io/I) Figure – 11 Path Length v/s Ln (Io/I) Figure – 12 Path Length v/s Ln (Io/I) Figure – 13 Path Length v/s Ln (Io/I) Figure - 14 Concentration V/s linear absorption coefficient Conclusion We studied the linear and mass attenuation coefficient of buffalo milk sample with different concentrations by adding water in the milk at the gamma ray energy 662 keV of gamma source Cs - 137 with narrowed beam. The result shows that as concentration of milk sample increases, mass attenuation coefficient decreases. Gamma dissociation law is valid for the milk sample. The other research work is in progress. Acknowledgement Authors are thankful to Prin. Dr. M. M. Andar, Secretary, M.E. Society, Pune, Prin. Dr. B.B. Thakur, Dr. S.L. Bonde, Dr. K.V. Desa, Head, Dept. of Physics, Nowrosjee Wadia College, Pune for encouragement to us. Authors are also thankful to Research Journal of Recent Sciences ______ _ _ _______________________________ ______________ _ ________ ISSN 2277 - 2502 Vol. 2 ( 3 ), 7 - 13 , March (201 3 ) Res. J. Recent Sci. International Science Congress Association 13 U.G.C.W.R.O., Pune and B.C.U.D., University of Pune, Pune for providing financial support for research. Authors are also thankful to Hon. President, Secretary an d Pincipal, S. V. S.’s, Dadasaheb Rawal College Dondaich, Dist. Dhule for encouragement to us. References 1. 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