Microsoft Word - 201-214 201| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 Gamma Ray Attenuation Coefficients for Lead Oxide and Iron Oxide Reinforced In Silicate Glasses as Radiation Shielding Windows Abbas J. Al-Saadi Basic Medical Science/ College of Dentistry/ Karbala University Abbas K. Saadon Dept. of Physics/College of Education for Pure Science (Ibn Al-Haitham)/ University of Baghdad E-mail: abbasj6@yahoo.com Received in :1February 2014 Accepted in :2June 2014 Abstract In this work, the mass attenuation coefficient, effective atomic number and half value layer parameters were calculated for silicate (SiO2) mixed with various levels of lead oxide and iron oxide as reinforced materials. SiO2 was used with different concentrations of PbO and Fe2O3 (25, 50 and 75 weight %). The glass system was prepared by the melt-quenching method. The attenuation parameters were calculated at photon energies varying from 1keV to 100MeV using the XCOM program (version 3.1). In addition, the mass attenuation coefficient and half value layer parameters for selected glass samples were experimentally determined at photon energies 0.662 and 1.28 MeV emitted from radioactive sources 137Cs and 22Na respectively in a collimated narrow beam geometry set-up using 2"x2" NaI (Tl) scintillation detector. These values are found to be in agreement with the values computed theoretically. Moreover, these results were also compared with those for the commercial window glass. The effective atomic number ( Zeff ) and half value layer (HVL) results indicate that pbO+SiO2 was better gamma ray attenuation than Fe2O3+SiO2 and commercial window glass. This indicates that PbO+SiO2 glasses can be used as gamma ray shielding in replace of both of them in this energy range. Keywords: Gamma ray, mass attenuation coefficient, linear attenuation coefficient, effective atomic number, half value layer, glass, radiation shielding materials. 202| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 Introduction Gamma-ray and X-ray attenuation coefficients are very important in both fundamental and applied science. They are invaluable in many applied fields, such as nuclear diagnostics, radiation protection, nuclear medicine, and radiation dosimetry. Protection of the body from unnecessary radiation exposure when working in a radiation area is a priority for every health physicist [1, 2]. Glass materials are possible alternatives for radiation shielding materials with two advantages brought by their transparency to visible light, and their properties can be modified by using composition and preparation techniques. Silicate glasses are the most commonly available commercial glasses due to ease of fabrication and excellent transmission of visible light [1,2]. Lead oxide (PbO) is a promising gamma ray shielding materials due to its strong absorption of gamma rays [3, 4]. Authors has explored the possibility of using glass as gamma ray shielding material in terms of heavy metal-silicate glasses in their research article[5, 6]. In photon interaction with composite materials, the atomic number cannot be represented uniquely by a single number across the entire energy region, as in the case of pure elements. This number for composite materials is called the effective atomic number and it varies with the photon energy [7]. Berger and Hubbell [8] have developed a computer program (XCOM) which calculates photon cross-sections and attenuation coefficients for pure elements and mixtures in the energy range of 1 keV to 100 GeV. In the present study, the shielding parameters such as mass attenuation coefficient (µm ), effective atomic number (Zeff) and half value layer (HVL) were calculated for lead-silicate (PbO -SiO2) and iron-silicate (Fe2O3-SiO2) glasses containing the same levels of concentration at photon energies varying from 1keV to 100MeV by using the (XCOM) program . Also, we measured the mass attenuation coefficient and half value layer of gamma-rays for PbO-SiO2 and Fe2O3-SiO2 glasses at 0.662 and 1.28 MeV photons by using NaI(Tl) scintillation detector. Lead silicate and iron silicate glasses were synthesized by using a melt quenching method. Theory The theoretical relations used in the present work are summarized in this part. A collimated beam of mono-energetic gamma ray is attenuated in matters according to the Lambert-Beer law [9,10]: )1(0 xeII  Where I0 is the initial intensity of gamma ray, I is the intensity of gamma ray after attenuation through a material of thickness x (cm) and µ is the linear attenuation coefficient (cm-1 ) of the material. Mass attenuation coefficient (µm ) of the material is obtained by dividing µ by the material density (ρ ). The mass attenuation coefficient, for a compound or mixture is given by [9,10]: )2()( im i im w   Where wi and (µm)i are the weight fraction and mass attenuation coefficient of the ith constituent element, respectively. For any compound, the total atomic cross section (σa) can be calculated from the knowledge of mass attenuation coefficient by the following formula [7, 11,12]: 203| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 )3(   i i i A m a A w N   Where NA is Avogadro's number and Ai is the atomic weight of ith element. Similarly, the total electronic cross section (σel) is given by [7, 11, 12]: )4()( 1  im i i i A el Z A f N  Where fi denotes the fractional abundance of the element i with respect to the number of atoms such that f1 + f2 + f3 + . . . + fi =1, Zi is the atomic number of ith element. Finally, by using Eqs. (3) and (4), the effective atomic number (Zeff) can be defined as:[7,11,12]: )5( el a effZ    The thickness of the material that reduces the photon beam intensity to half of its original value (I0), i.e. (½) I0, is called the half value layer (HVL) and is given by [9]: where µ is linear attenuation coefficient of the material at a given photon energy. Materials and methods Sample preparation and density measurements Starting materials of (99.9% purity) were used in the present work for Fe2O3, PbO and SiO2. All the chemicals were weighed accurately using an electrical balance with an accuracy of 0.001g, grounded to fine powder and mixed thoroughly. The samples were prepared by mixing of PbO and Fe2O3 in concentrations of 25, 50 and 75 (weight %) with SiO2. Each batch of about 50 g in alumina crucible was melt in an electrical furnace for one hour, at 1250 0C . The melts were then poured between the stainless steel molds. The quenched glasses were annealed at 500 0C for 3 hours to reduce thermal stress, and cooled down to the room temperature. At the room temperature, densities of glass samples were measured with the Archimedes' method using xylene as an immersion liquid. The density of glass sample (ρ) was calculated by the formula: )7(L BA A WW W     Where WA and WB are the weight of the sample in air and the weight of the sample in xylene, respectively and ρL is density of xylene. The chemical compositions, % by weight, and the density of the glass samples are given in Table 1. Fig.1 shows density plots of the glass for both systems. It is seen that the density of the glass samples increases with higher Fe2O3 and PbO contents, because of higher molecular weight of Fe2O3 and PbO in comparison to SiO2. The PbO+SiO2 glass samples prepared in our work gave higher densities than the Fe2O3+SiO2 glasses over all ranges of SiO2 concentration which may be contributed to higher atomic weight of the lead. Calculation of the total mass attenuation coefficients The theoretical values of mass attenuation coefficient ( μm ) were calculated using the XCOM computer program (version 3.1). The used XCOM program have been recently )6( 693.02ln  HVL 204| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 modified to calculate the total mass attenuation coefficients for elements, compounds and mixtures at photon energies varying from from1 keV to 100 GeV [8], and provides total cross section as well as partial cross sections for various interaction processes.   Gamma ray measurements by NaI (Tl) scintillation detector Experimental measurements have been performed to investigate attenuation values of gamma rays for the six Fe2O3, PbO / SiO2 glass samples. The present experimental arrangement can be identified as being of narrow beam attenuation geometry which gives gamma ray buildup factor equal to unity. The gamma ray spectrometer is energy calibrated using standard multi energy gamma sources : mix source 137Cs (has photo peak 662keV) with 241Am (has photo peak 59.5keV) manufactured by LD.G.mbh-Germany. in addition using 60Co (have photo peaks 1.17 and 1.33 MeV). The diagram of experimental setup is shown in Fig. 2a. All samples were used in the form of a tablets plate with 2 cm diameter and thickness 0.4 cm. Samples with different thicknesses ( 0.4 -1.6 ) cm were arranged in front of a collimated beam emerged from radioactive source. Two standard radioactive gamma sources 137Cs (0.662 MeV) of 71.62µCi ( 2.65 MBq ) strength and 22Na (1.280 MeV) of 0.445 µCi ( 16.47 kBq ) strength were used. The intensities of gamma photons were measured by using 2"x2" NaI (Tl) scintillation detector (Saint- Gobain Crystals Bicron). The detector was coupled to pre-amplifier, amplifier, power supply and computer analyzer with LD Didactic GmbH sensor-cassy. The detector was also housed in a thick lead jacket to reduce the radiation background as low possible, the distance between detector and source was 15cm [12]. For each sample and energy, I0 and I intensities which are without and after attenuation were measured by a NaI (Tl) detector. The photo peak areas have been calculated from the spectrum obtained for each measurement. Background spectra were recorded for the same time period (1000 S) and subtracted from each spectrum. The typical spectra of the radioactive sources 137Cs measured in this work are shown in Fig. 2b. Results and Discussion - Mass attenuation coefficient The calculated values of mass attenuation coefficient for PbO+SiO2 and Fe2O3+SiO2 glass samples at photon energies varying from 1keV to 100MeV are shown in Figs.3 and 4 respectively. Mass attenuation coefficient for Pb+SiO2 and Fe2O3 +SiO2 glass samples sharply decrease with increase of the photon energy from 0.001 to 0.1 MeV with a peak due to photoelectric effect around the K,L,M-absorption edges of the lead, K absorption edge of the silicon and K absorption edge of the iron. At photon energy from 0.1 to 5 MeV the variation is slightly decreased with the increase of the photon energy. While, at photon energies from 5 to 100 MeV, inconsiderable the increase of the mass attenuation coefficient values have been observed with increase of the photon energy, this may be due to the dominance of pair production in this energy region. Figs.3 and 4 can also be seen the mass attenuation coefficients of PbO+SiO2 glass samples are higher than that of Fe2O3+SiO2 glasses. This means that there is more photon absorption in the PbO+SiO2 glass than in the Fe2O3+SiO2 glass. Mass attenuation coefficient increases (Fig.3) with the increase in weight fraction of PbO, this can be attributed to increasing values of Pb which has higher atomic number as compared to other elements. It is estimated that 75 wt% PbO+25wt% SiO2 glass sample represents best glass sample in terms of gamma ray shielding applications. Figs. 5 and 6 show plot of ln (I0/I) versus thickness samples at the 0.662 and 1.28 MeV gamma ray beams using this graphs, The slope of the graphs gives the value of the linear attenuation coefficient (μ ) of glass samples at that particular energy. Tables 2 and 3 give the experimental and theoretical values of mass attenuation coefficients (μm) for glass samples. The comparison of their measurements with the theoretical values is done by calculating the relative deviation 205| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 (RD). We found the deviation mostly below 5%. In general, the experimental values are in a good agreement with the theoretical values. -Effective Atomic Numbers The variation of effective atomic numbers for selected glass samples (Zeff ) with photon energy were calculated from Eq.(5) and plotted in Fig.7. The effective atomic numbers of PbO+SiO2 glasses are greater than Fe2O3 +SiO2 glasses'. In addition, Zeff increases with the increase of Fe2O3 and PbO concentrations. The Zeff values for PbO+SiO2 glasses show a broad peak and a maximum value at 0.01 MeV and minima at 1 MeV. The variation of Zeff with energy may be attributed to the relative domination of the partial processes, viz. photoelectric effect, coherent scattering, incoherent scattering and pair production. At low energies the photoelectric effect is dominant and hence Zeff for the photon absorption is mainly described by Zeff for this partial process. Similarly, at higher energies the contribution due to scattering and pair production process will be more in comparison with photoelectric effect and this will have its effect on Zeff for photon absorption. Hence at low energies (up to 0.1 MeV), where photoelectric effect dominates, Zeff value is more and at intermediate energies (0.1- 1 MeV), where the scattering process dominate, Zeff value is less. Finally, at higher energies (more than 1.022MeV) the pair production process dominates Zeff value increase with the increase of photon energy. Therefore, Zeff for photon energy absorption varies from a higher value at lower energies to a lower value at intermediate energies with a peak due to photoelectric effect around the K-absorption edge of the lead (0.088MeV). -Half value layer The half value layers (HVL) of Fe2O3+SiO2 and PbO+SiO2 glass samples at photon energies varying from 1keV to 100MeV are shown in Figs.8 and 9 respectively with standard commercial window glass taken from literature [13]. It is found that the PbO+SiO2 glasses have better shielding properties (gives low HVL at all energies) than commercial window glass and Fe2O3+SiO2, reflecting the advantage of lead component in radiation shielding glass. The HVL values for the PbO+SiO2, Fe2O3+SiO2 glass samples and standard commercial window glass were also experimentally determined at gamma energies 0.662 and 1.28 MeV as shown in Tables 4 and 5 in addition that plotted in Fig.10. It is evident that the 50wt.%Fe2O3+50 wt.%SiO2 and 25wt.%PbO+75wt.%SiO2 glass samples have the same HVL values because they have similar effective atomic numbers at particular energies (see Fig.7). The composite of 75 wt.% PbO+25wt.% SiO2 glass sample have low HVL values than those other selected glass samples, this can be attributed to increasing values of Pb which has higher atomic number as compared to other elements. Conclusions From the measurement and calculation of gamma attenuation coefficients in Fe2O3 and PbO reinforced in silicate glasses, it can be concluded: 1. The mass attenuation coefficients of the PbO+ SiO2 glasses are higher than that of the Fe2O3+ SiO2 glasses at the same incident photon energy. The 75 wt.% PbO +25 wt.% SiO2 proved to be more efficient for gamma rays attenuation. 2. The results show that the effective atomic numbers of PbO+ SiO2 glasses are larger than that of Fe2O3+ SiO2 glasses and both are greater than SiO2 glass sample. Moreover, the effective atomic numbers increase with the increase of fraction weight of Fe2O3 and PbO. 3. In the case of Fe2O3+ SiO2 glasses, there is only a little change in the half value layer with increase of Fe2O3 concentration. We found that the HVL in 50wt.%Fe2O3+50 wt.%SiO2 and 25wt.%PbO+75wt.%SiO2 glasses have equivalent values. 4.The theoretical values of gamma ray attenuation coefficients were generally in good agreement with experimental obtained values. 206| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 References 1. Kerur, B.;Manjula, V.; Lagare, M. and Kumar, S. (2009) Mass attenuation coefficient of saccharides for X-rays in the energy range from 8 keV to 32 keV , Radiat Meas. 44 63–67. 2. Maqbool, M. (2004) Determination of transfer functions of MCP-200 alloy using 6 MV photon beam for beam intensity modulation , J. Mech Med. Biol. 4, 305–310. 3. Manohara, S.R.; Hanagodimath, S.M. and Gerward, L. (2009) , Photon interaction and energy absorption in glass: A transparent gamma ray shield , J. Nucl. Mater. 393 ,465-472. 4. Singh, K.J.; Singh ,N.; Kaundal, R.S. and Singh, K. (2008) Gamma-ray shielding and structural properties of PbO-SiO2 glass , Nucl. Instr. and Meth.B, 266, 944–948. 5. Kaewkhao, J.; Pokaipisit, A. and Limsuwan, P. (2010) Study on Borate Glass system containing with Bi2O3 and BaO for Gamma rays Shielding materials Comparison with PbO , Nucl. Mat., 399, 38–40. 6. Kaundal, R.S.; Sandeep, K. ;Narveer, S. and Singh, K.J. ( 2010) Investigation of structural properties of lead strontium borate glasses for gamma ray shielding applications , Phy.Chem. of solids, 71 , 1191-1195. 7. Shivalinge, G.; Krishnaveni, S.; Yashoda, T.; Umesh, T. and Ramakrishna, G. (2004) Photon mass attenuation coefficients, effective atomic numbers and electron densities of some thermo luminescent dosimetric compounds ,Pramana J. Phys., 63(3): 529- 541. 8. Berger, M.J. and Hubbell, J.H., (1987)"Photon cross sections on a personal Computer, National Institute of Standards and Technology, NBSIR 87– 3597, XCOM, Gaithersburg, MD 20899, USA. 9. Arthur B. Chilton , Shultis J.K. and Faw R.E. (1984),Principles of radiation shielding, Prentice- Hall ,Englewood Cliffs , New Jercy 10. Raje D.V. and Chaudhari L.M. (2010), Mass attenuation of soil samples in Maharashtra (India ) by using gamma energy at 0.662 MeV, Bulg. J. Phys. 37, 158- 164. 11. Niranjan, R.S., Rudrasw, B. and Dhananjaya, N. (2012) Effective atomic number, electron density and kerma of gamma radiation for oxides of lanthanides , Pramana J. Phys., 78, No. 3, 451–458. 12. Hana, I. and Demirb ,L. (2010) ,Studies on effective atomic numbers, electron densities and mass attenuation coefficients in Au alloys, Journal of X-Ray Science and Technology 18, 39–46. 13. Mc Conn Jr, Gesh CJ. Pagh RT. Rucker RA. and Williams III RG. (2011). Radiation Portal Monitor Project Compendium of Material Composition Data for Radiation Transport Modeling , PIET- 43741-TM-963 PNNL15870 Rev. 1. 207| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 Table No. (1): Chemical composition and density of glass samples Sample number Composition (wt%) Density (g/cm3) PbO Fe2O3 SiO2 1 - - 100 1.9400 ±0.0132 2 25 - 75 2.7215 ±0.0120 3 50 - 50 3.8351 ±0.0157 4 75 25 5.0219 ±0.0140 5 - 25 75 2.6091±0.0132 6 - 50 50 2.9372±0.0161 7 - 75 25 3.4179±0.0154 Table No.( 2): Comparison between mass attenuation coefficients µm (cm2/ g) for PbO+SiO2 and Fe2O3 +SiO2 glasses at photon energy 0.662 MeV Fe2O3 or PbO (wt.%) PbO+SiO2 glass Fe2O3+SiO2 glass µm theory (cm2/ g) µm experiment (cm2/ g) RD % µm theory (cm2/ g) µm experiment (cm2/ g) RD % 25 0.08490 0.08352± 0.0025 1.63 0.07660 0.07994 ± 0.0022 4.36 50 0.09252 0.09476 ± 0.0022 2.42 0.07594 0.07969 ±0.0018 4.94 75 0.10010 0.09857 ± 1.53 0.07527 0.07244 3.76 Table No. (4): Comparison between half value layer HVL (cm) for PbO+SiO2 and Fe2O3 +SiO glasses at photon energy 0.662 MeV Fe2O3 or PbO (wt.%) PbO+SiO2 glass Fe2O3+SiO2 glass HVL theory (cm) HVL experiment (cm) RD % HVL theory (cm) HVL experiment (cm) RD % 25 3.000 3.050 ± 0.089 1.67 3.468 3.323 ± 0.089 4.18 50 1.953 1.907 ± 0.043 2.36 3.108 2.961 ± 0.065 4.30 75 1.390 1.400 ± 0.056 0.72 2.694 2.799 ± 0.108 3.90 Table No.(3): Comparison between mass attenuation coefficients µm (cm2 /g) for PbO+SiO2 and Fe2O3 +SiO2 glasses at photon energy 1.28 MeV Fe2O3 or PbO (wt. %) PbO+SiO2 glass Fe2O3+SiO2 glass µm theory (cm2/ g) µm experiment (cm2/ g) RD % µm theory (cm2/ g) µm experiment (cm2/ g) RD % 25 0.05659 0.05884 ±0.0021 3.98 0.05566 0.05584 ±0.0010 0.32 50 0.05694 0.05411 ±0.0010 4.97 0.05507 0.05417 ± 0.0012 1.63 208| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 Figure No.(2a): Experimental setup to determine mass attenuation coefficient. 0 10 20 30 40 50 60 70 80 0 1 2 3 4 5 6 Fig. 1. Densities of the Fe 2 O 3 +SiO 2 and the PbO+SiO 2 glass systems. D e n si ty ( g / cm 3 ) Weight (%) of Fe 2 O 3 and PbO glass samples Fe 2 O 3 + SiO 2 glass samples PbO + SiO 2 glass samples Table No.5: Comparison between half value layer HVL (cm) for PbO+SiO2 and Fe2O3 +SiO2 glasses at photon energy 1.28 MeV Fe2O3 or PbO (wt.%) PbO+SiO2 glass Fe2O3+SiO2 glass HVL theory (cm) HVL experiment (cm) RD % HVL theory (cm) HVL experiment (cm) RD % 25 4.501 4.329 ± 0.149 3.82 4.773 4.758 ± 0.084 0.31 50 3.174 3.340 ± 0.061 5.23 4.285 4.356 ± 0.094 1.66 75 2.409 2.453 ± 0.043 1.83 3.722 3.796 ± 0.136 1.99 209| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 1E-3 0.01 0.1 1 10 100 0.01 0.1 1 10 100 1000 10000 K- absorption edge of the silicon M- absorption edge of the lead L-absorption edge of the lead K-absorption edge of the lead Figure 3. Mass attenuation coefficient as a function of photon energy (1keV to 100 MeV) for SiO 2 and PbO-SiO2 glasses M a ss a tt e n u a tio n c o e ff ic ie n t ( cm 2 .g m -1 ) Photon energy (MeV) SiO 2 25% PbO + 75% SiO 2 50% PbO + 50% SiO 2 75% PbO + 25% SiO 2 210| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 1E-3 0.01 0.1 1 10 100 0.01 0.1 1 10 100 1000 10000 K- absorption edge of the iron K- absorption edge of the silicon Figure 4. Mass attenuation coefficient as a function of photon energy (1keV to 100 MeV) for SiO 2 and Fe 2 O 3 -SiO2 glasses M a s s a tt e n u a tio n c o e ff ic ie n t ( cm 2 . g m -1 ) Photon energy (MeV) SiO 2 25% Fe 2 O 3 + 75% SiO 2 50% Fe 2 O 3 + 50% SiO 2 75% Fe 2 O 3 + 25% SiO 2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Figure 5. ln (I 0 /I) versus thickness for selected samples at 0.662 MeV. ln ( I 0 / I ) Thickness (cm) 25% Fe 2 O 3 + 75% SiO 2 50% Fe 2 O 3 + 50% SiO 2 75% Fe 2 O 3 + 25% SiO 2 25% PbO + 75% SiO 2 50% PbO + 50% SiO 2 75% PbO + 25% SiO 2 211| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0.0 0.1 0.2 0.3 0.4 0.5 Figure 6. ln (I 0 /I) versus thickness for selected samples at 1.28 MeV. ln ( I 0 / I ) Thickness (cm) 25% Fe 2 O 3 + 75% SiO 2 50% Fe 2 O 3 + 50% SiO 2 75% Fe 2 O 3 + 25% SiO 2 25% PbO + 75% SiO 2 50% PbO + 50% SiO 2 75% PbO + 25% SiO 2 1E-3 0.01 0.1 1 10 100 8 12 16 20 24 28 32 36 40 44 K-absorption edge of the lead (0.088 MeV) Figure 7. Energy dependence of effective atomic number Z eff for total photon interaction. Z e ff ( e le ct ro n / a to m ) phton energy (MeV) SiO 2 25% Fe 2 O 3 +75iO 2 50% Fe 2 O 3 +50% SiO 2 75% Fe 2 O 3 +25% SiO 2 25% PbO+75% SiO 2 50% PbO+50% SiO 2 75% PbO+25% SiO 2 212| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 1E-3 0.01 0.1 1 10 100 1E-5 1E-4 1E-3 0.01 0.1 1 10 Figure 8. Half value layer as a function of photon energy (1keV-100MeV) in the Fe 2 O 3 -SiO 2 glass and commerical glass. H V L ( c m ) Photon energy (MeV) commerical window glass 25% Fe 2 O 3 +75iO 2 50% Fe 2 O 3 +50iO 2 75% Fe 2 O 3 +25iO 2 sio 2 213| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 c om m er ic al w in do w g la ss 10 0% S io 2 2 5% Fe 2O 3 + 75 % S iO 2 5 0% Fe 2O 3 + 50 % S iO 2 7 5% Fe 2O 3 + 25 % S iO 2 2 5% P bO + 7 5% S iO 2 5 0% P bO + 5 0% S iO 2 7 5% P bO + 2 5% S iO 2 0 1 2 3 4 5 6 7 Fig. 10. Half value layer (HVL) of Fe 2 O 3 +SiO 2 glasses compared with those of PbO+SiO 2 glasses and commercial window glass at 0.662 and 1.28 MeV. H a lf v a lu e la ye r ( cm ) Material at photon energy 0.662 MeV at photon energy 1.28 MeV 214| Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 أوكسيدو الرصاص وكسيدأب معامالت توھين اشعة كاما في الزجاج المدعم نوافذ للتدريع األشعاعيكالحديد ديعباس جواد السع كربالءجامعة /كلية طب األسنان عباس كريم سعدون بغدادجامعة )/ابن الھيثم للعلوم الصرفة ( كلية التربية/قسم الفيزياء 2014حزيران 2قبل البحث : 2014شباط 1استلم البحث : الخالصة ين الكتلي والعدد الذري المؤثر و سمك النصف لنماذج زجاجية مكونة من ھفي ھذا البحث حساب معامل التوتم ,wt. )25 % مختلفة وزنية واوكسيد الرصاص بتراكيز ,اوكسيد السليكون مادة اساس مدعمة باوكسيد الحديد الثالثي العالميباستخدام البرنامج 100MeV الى1keV ) عند مدى واسع من طاقة الفوتون تراوحت من 75 ,50 (XCOM) يقة من اشعة كاما عند ضباستخدام حزمة عمليا للنماذج وسمك النصف معامل التوھين الكتلي حسب. كذلك لھذا عملاست على التوالي.   Na22و Cs 137ن النظائر المشعة المنبعثة م 1.28MeVو MeV 0.662الطاقات  "x2"2الكاشف الوميضي الغرض NaI(Tl) فضال عن ذلك قورنت النتائج أيضا فكانت ھذه القيم موافقة للقيم النظرية . أفضل توھينا ألشعة 2PbO +SiO مع زجاج النوافذ التجاري. تشير نتائج العدد الذري المؤثر وسمك النصف أن زجاج للحماية من أشعة 2PbO +SiO, وزجاج النوافذ التجاري وھذا يبين استعمال الزجاج SiO3O2Fe+2كاما من الزجاج وزجاج النوافذ التجاري في ھذا المدى من الطاقة. SiO3O2Fe+2كاما بدل الزجاج سمك النصف، الزجاج، ،العدد الذري المؤثر الخطي، التوھين ، معاملأشعة كاما ,معامل التوھين الكتلي الكلمات المفتاحية: .مواد التدريع