Calculation and Study of Gamma ray Attenuation Coefficients for Different Composites

Transcription

1 Ibn Al-Haitham Journal or Pure and Applied Science No. Vol. Year العدد المجلد السنة Calculation and Study o Gamma ray Attenuation Coeicients or Dierent Composites K.H.Mahdi, Z.S.Ahmed*, A.F.Mkhaiber Department o Physics, College o Education Ibn Al-Haithem, University o Baghdad *Ministry o Science and Technology. Received in :18 Sptember 211, Accepted in: 12 February 212 Abstract In this work, the total linear attenuation coeicients (cm -1 ) were calculated and studied or particulate reinorced polymer-based composites. Unsaturated polyester (UP) resin was used as a matrix illed with dierent concentrations o Al, Fe, and Pb metal powders as reinorcements. The eect o the metal powders addition at dierent weight percentages in the range o (1,2,,4,5)wt % and gamma energy on attenuation coeicients was studied. The results show, as the metallic particulates content increase, the attenuation coeicients will increase too, while it, were exhibited a decrease in their values when the gamma energy increase.the total linear attenuation coeicients o gamma ray or 15 composites have been calculated using the XCOM program (version.1) in the energy range o.1-2 MeV. Key words: linear attenuation coeicients, composite materials, gamma ray. Introduction Shielding is one o the most eective radiation protection methods; others include time and distance. With shielding, radiation dose can be lowered to a desired level [1].Furthermore; dierent types o radiation can be shielded by dierent types o materials [2]. For shield designs, gamma ray was one o the main types o nuclear radiation, which have to be considered; since any shield attenuates the gamma rays will be more eective or attenuating other radiations []. Recently, there was a continuous demand or improved polymers or use as shielding materials [4]. Thereore, composite materials used or this purpose. Composites is a material brought about by combining materials diering in composition or orm on a macroscale or the purpose o obtaining speciic characteristics and properties. Composites consist rom two components: matrix and reinorcement [5]. Reinorcement materials played the important role to improve the matrix properties. Since polymeric materials are on their own hydrocarbonic substances we would expect good neutron moderation then, with the good choice o metallic illers, gamma rays and X-rays could be also shielded [6,7].Thereore, in this study, we attempted to prepare and characterize the polymer based composite radiation shields using unsaturated polyester resin as a matrix and Al, Fe, and Pb as iller with dierent concentrations (1,2,,4,5)wt%. Then, the eect o gamma energy and iller concentrations on attenuation coeicients was studied. Physics - 1

2 ﻣﺠﻠﺔ ﺇﺑﻦ ﺍﻟﻬﻴﺜﻢ ﻟﻠﻌﻠﻮﻡ ﺍﻟﺼﺮﻓﺔ ﻭ ﺍﻟﺘﻄﺒﻴﻘﻴﺔ Ibn Al-Haitham Journal or Pure and Applied Science No. Vol. Year ﺍﻟﺴﻨﺔ ﺍﻟﻤﺠﻠﺪ ﺍﻟﻌﺪﺩ Linear attenuation coeicient ( ) : In the design shielding materials, the linear attenuation coeicient ( ) which is deined as the probability o a radiation interacting with a material per unit path length, is important quantity and its magnitude depends on the incident photon energy and on the atomic number o the material, as well as, on the density ( ρ ) o the shielding material [8].Also,the mass attenuation coeicient ( / ρ ) (cm2.g-1) directly measures the eectiveness o a shielding material based upon unit mass o material. Generally, calculations o the mass attenuation coeicient at high energies are widely needed and used as a radiation shielding design database or radiation sources, reactors and particle accelerators.[9]. Calculation o the total linear attenuation coeicients ( ): In shielding calculations, materials made o homogeneous mixture o elements are requently encountered. For a mixture o known composition, the total mass attenuation coeicient μ/ρ (cm2 g -1) can be determined rom basic data by relationships [1]: = = N iσ i (1) (2) i i i wi ρ = ρ i i Where : the total linear attenuation coeicient, cm-1. Ni: number o atoms, cm-. σ i : Microscopic cross section, cm2. ρ i : Density o the i th constituent, g.cm-. wi : Proportion by weight o i th constituent. The total linear attenuation coeicients ( ) were calculated or the 15 (unsaturated polyester / metal ) composite samples using a computer program called XCOM (version.1). The used XCOM program and database cross sections or elements ranging rom Z=1 to 1 have been recently modiied to calculate the total mass attenuation coeicients ( / ρ ) or elements, compounds and mixtures rom1 kev to 1 GeV [11], and provides total cross section as well as partial cross sections or various interaction processes. With a known Physics - 14

3 Ibn Al-Haitham Journal or Pure and Applied Science No. Vol. Year 212 العدد المجلد السنة 212 density ( ρ ) o shield materials, the total linear attenuation coeicients ( ) were extracted rom calculated results o XCOM. The density o composite materials was calculated using the rule o mixtures ormula given by the ollowing equation [12]: ρ c ( V ) ρ m = V ρ + 1 () equation: Where ρ ρ, ρ : Density o composite body, reinorcement and the matrix materials respectively., c m V : Fractional volume or reinorcement material which could be calculated rom the V = 1 ψ ρ / 1 +. ψ ρm 1 (4) W = W c 1% : Fractional weight or reinorcement materials: ψ Where ψ (5) W W + W c = (6) m W W, W c, : Weight o composite, reinorcement and matrix materials respectively [1]. m Results and Discussion In ig (1), the linear attenuation coeicient ( ) was displayed as a unction o the applied energy, it was clear that linear attenuation coeicient ( ) sharply decreased with the increase o the photon energy in the range (.1-1) MeV or all composites.such a behavior could be ascribed to the photoelectric and Compton scattering which were the main predominant interactions in this region. This sharp decrease was considered to be an indication that the ( ) was very sensitive to the photon energy. In the range (1-5) MeV the total linear attenuation coeicients ( ) were noticed to decrease with the increase o the photon energy or all composites. In this region, the Physics - 15

4 Ibn Al-Haitham Journal or Pure and Applied Science No. Vol. Year 212 العدد المجلد السنة 212 dominant interaction is pair production [14]. This slight decrease indicates that the ( ) is not very sensitive to the variations in the photon energy in this region. In the region (E>5) MeV, there was no signiicant decrease in the values o total linear attenuation coeicient ( ) with increase o the photon energy or all composite samples and this could be attributed to the successive collisions, due to several Compton scatterings. There is an agreement with the results o [14,15]. In ig (2), the total linear attenuation coeicient ( ) displayed as a unction o concentration o metal powders (Al, Fe and Pb) at the dierent energies. From this igure one may notice that the total linear attenuation coeicient ( ) increased with the increase o metal concentration, especially within low photon energy, but at higher energies there was no clear change in the ( ).This could explain that as the concentration o metal powders increased, the absorption process will also increase and this mean an increase in the ( ) values. From table (1), the total linear attenuation coeicients ( ) calculated or the unsaturated polyester (UP) had the minimum values and reached a maximum values or composite samples containing 5% o dierent powder metals. The improved shielding capability o (UP) metal powder composites could be explained on the act that, unsaturated polyester (UP) matrix is a bad shielding material, but when some illing metals powders add to it, it was modiied and become a good shielding material. In other word, an increase in the probability o interaction between the incident gamma radiation and the shield atoms was happened. Thus, one may conclude that, the total linear attenuation coeicient o the composites was increased with increased iller content in the composites samples prepared. Reerences 1- Stewart,D.C.(1985),Data or radioactive waste management and nuclear applications, John Wiley Sons Inc, New York. 2- Chilton,A.B.;Shultis,J.K.andFaw,R.E.(1984)"Principles o radiation shielding", Prentice- Hall Inc, New Jersey. - Goldstein,H.(1959) Fundamental Aspects o Reactor Shielding, Addison-Wesley, Reading, MA. 4- Milewski, J.V. ( 1987),Handbook o Fillers or Plastics", Van Nostrand Reinhold. 5- Brian, S. M.( 24),An Introduction To Materials Engineering And Science For Chemical And Materials Engineers", John Wiley & Sons, New Jersey. 6- Allen,R.T.and Edwards, S.C.( 1987),The Repair o Concrete Structures, Blackies, Glasgow and London. 7- Mukherjee, P.K.and Deans, J.J. ( 1988),Service perormance o nucl containment concrete, Concrete International 1, Wood,J.(1982),Computational Methods in Reactor Shielding", Pergamon Press, Inc., New York. 9- Kaplan, M.F.( 1989),Concrete Radiation Shielding, John Wiley & Sons, New York. 1- Seltzer, M.S. ( 199), Calculation o photon mass energy-transer and mass energy absorption coeicients", Radiation Research, 16; Berger, M.J.and Hubbell, J.H. ( 1987), Photon Cross Sections on a Personal Computer.National Institute o Standards and Technology, NBSIR , XCOM, Gaithersburg, MD 2899, USA. Physics - 16

5 Ibn Al-Haitham Journal or Pure and Applied Science No. Vol. Year 212 العدد المجلد السنة Schwartz, M.M. ( 1984),composite Materials,Hand book Mc Graw- Hill co. 1- Hull, D. (1981),An introduction to composite materials" First eddition, Cambridge University press U. K. 14- Akkurt,I.(211),Gamma ray attenuation coeicient o microalloyed stainless steel, Arab J Sci Eng,6 ; Korkut,T. (211),A new radiation shielding material, Annals o nuclear energy.8 ; Physics - 17

6 Ibn Al-Haitham Journal or Pure and Applied Science No. Vol. Year 212 العدد المجلد السنة 212 Table (1):Linear attenuation coeicient values at dierent energies or composite samples illed with( Al,Fe and Pb) powders at dierent weight percentages Al ENERGY (Mev) (cm -1 ) Al 1% wt Al 2% wt Al % wt Al 4% wt Al 5% wt Fe ENERGY (Mev) ( cm -1 ) Fe1% wt Fe2% wt Fe% wt Fe4% wt Fe5% wt Pb ENERGY (Mev) ( cm -1 ) Pb 1% wt Pb 2% wt Pb % wt Pb 4% wt Pb 5% wt Physics - 18

7 ﻣﺠﻠﺔ ﺇﺑﻦ ﺍﻟﻬﻴﺜﻢ ﻟﻠﻌﻠﻮﻡ ﺍﻟﺼﺮﻓﺔ ﻭ ﺍﻟﺘﻄﺒﻴﻘﻴﺔ Ibn Al-Haitham Journal or Pure and Applied Science No. Vol. Year ﺍﻟﺴﻨﺔ ﺍﻟﻤﺠﻠﺪ Al 1 (cm -1 ) Al 1% Al 2% Al 5% Al %.1 Al 4% Energy (Mev) Cu 1 (cm -1 ) Fe1% Fe2%.1 Fe% Fe4% Fe5% Energy (Mev) Pb (cm -1 ) 1 Pb1% 1 Pb2% Pb% Pb4%.1 Pb5% Energy (Mev) Fig.(1):Total linear attenuation coeicient ( ) as a unction o energy (E) at dierent concentrations o (Al,Fe and Pb) Physics - 19 ﺍﻟﻌﺪﺩ

8 ﻣﺠﻠﺔ ﺇﺑﻦ ﺍﻟﻬﻴﺜﻢ ﻟﻠﻌﻠﻮﻡ ﺍﻟﺼﺮﻓﺔ ﻭ ﺍﻟﺘﻄﺒﻴﻘﻴﺔ Ibn Al-Haitham Journal or Pure and Applied Science Vol Year ﺍﻟﺴﻨﺔ ﺍﻟﻤﺠﻠﺪ. (cm-1).1 Mev..5Mev.2 1 Mev.15 5 Mev.1 1 Mev.5 15 Mev 2 Mev Al wt% Mev.5Mev (cm-1).4 1 Mev. 5 Mev 1 Mev.2 15 Mev.1 2 Mev 1 2 Fe wt% (cm-1) No..1 Mev 5.5Mev 4 1 Mev 5 Mev 1 Mev 2 15 Mev 1 2 Mev 1 2 Pb wt% Fig.(2):Total linear attenuation coeicient ( ) as a unction o concentration o (Al,Fe and Pb) at dierent energies Physics - 14 ﺍﻟﻌﺪﺩ

9 ﻣﺠﻠﺔ ﺇﺑﻦ ﺍﻟﻬﻴﺜﻢ ﻟﻠﻌﻠﻮﻡ ﺍﻟﺼﺮﻓﺔ ﻭ ﺍﻟﺘﻄﺒﻴﻘﻴﺔ ﺍﻟﻌﺪﺩ ﺍﻟﻤﺠﻠﺪ ﺍﻟﺴﻨﺔ Ibn Al-Haitham Journal or Pure and Applied Science Year Vol. No. ﺤﺴﺎب ودراﺴﺔ ﻤﻌﺎﻤﻝ ﺘوﻫﻴن أﺸﻌﺔ ﻛﺎﻤﺎ ﻟﻤﺘراﻛﺒﺎت ﻤﺨﺘﻠﻔﺔ ﺨﺎﻟد ﻫﺎدي ﻤﻬدي زﻴﺎد ﺸﻬﺎب اﺤﻤد* اﺤﻤد ﻓﺎﻀﻝ ﻤﺨﻴﺒر ﻗﺴم اﻟﻔﻴزﻴﺎء ﻛﻠﻴﺔ اﻟﺘرﺒﻴﺔ ﺠﺎﻤﻌﺔ ﺒﻐداد * وزارة اﻟﻌﻠوم واﻟﺘﻛﻨﻠوﺠﻴﺎ اﺴﺘﻠم اﻟﺒﺤث ﻓﻲ 18 : اﻴﻠوﻝ 211 ﻗﺒﻝ اﻟﺒﺤث ﻓﻲ 12 : ﺸﺒﺎط 212 اﻟﺨﻼﺼﺔ ودرس ﻤﻌﺎﻤﻝ اﻟﺘوﻫﻴن اﻟﺨطﻲ اﻟﻛﻠﻲ ) ( cm-1) ( ﻟﻤﺘراﻛﺒﺎت ﺒوﻟﻴﻤﻴرﻴﺔ ﻤدﻋﻤﺔ ﺒﺎﻟدﻗﺎﺌق ﻓﻲ ﻫذا اﻟﺒﺤث ﺤﺴب ﻤﻛوﻨﺔ ﻤن راﺘﻨﺞ اﻟﺒوﻟﻲ اﺴﺘر ﻏﻴر اﻟﻤﺸﺒﻊ ) ) ( UP ﻛﻤﺎدة أﺴﺎس( ﻤدﻋم ﺒﺘراﻛﻴز ﻤﺨﺘﻠﻔﺔ ﻤن )اﻷﻟﻤﻨﻴوم واﻟﺤدﻴد واﻟرﺼﺎص( )ﻤواد ﺘدﻋﻴم(. درس ﺘﺄﺜﻴر اﻀﺎﻓﺔ اﻟﻤﺴﺎﺤﻴق اﻟﻤﻌدﻨﻴﺔ ﻋﻨد ﺘراﻛﻴز ) %( وﻛذﻟك طﺎﻗﺔ أﺸﻌﺔ ﻛﺎﻤﺎ ﻋﻠﻰ ﻤﻌﺎﻤﻼت اﻟﺘوﻫﻴن. أظﻬرت اﻟﻨﺘﺎﺌﺞ اﻨﻪ ﻋﻨدﻤﺎ ﻴزداد ﺘرﻛﻴز اﻟﻤﻌدن ﻓﺎن ﻤﻌﺎﻤﻝ اﻟﺘوﻫﻴن ﺴوف ﻴزداد اﻴﻀﺎ ﺒﻴﻨﻤﺎ ظﻬر ان ﻫﻨﺎك ﻨﻘﺼﺎﻨﺎ ﻓﻲ ﻗﻴم ﻤﻌﺎﻤﻼت اﻟﺘوﻫﻴن ﻋﻨدﻤﺎ ﺘزداد طﺎﻗﺔ اﺸﻌﺔ ﻛﺎﻤﺎ. ان ﻤﻌﺎﻤﻼت اﻟﺘوﻫﻴن اﻟﺨطﻴﺔ اﻟﻛﻠﻴﺔ وﻟ 15 ﻤﺘراﻛﺒﺔ ﺤﺴﺒت ﺒﺎﺴﺘﺨدام اﻟﺒرﻨﺎﻤﺞ ) ( version.1 ) (XCOM ﻀﻤن اﻟﻤدى اﻟطﺎﻗﻲ ) (2-.1 ﻤﻠﻴون إﻟﻛﺘرون ﻓوﻟت. اﻟﻛﻠﻤﺎت اﻟﻤﻔﺘﺎﺤﻴﺔ : ﻤﻌﺎﻤﻝ اﻟﺘوﻫﻴن اﻟﺨطﻲ اﻟﻤواد اﻟﻤﺘراﻛﺒﺔ أﺸﻌﺔ ﻛﺎﻤﺎ. Physics - 141