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Photon-shielding performance of bismuth oxychloride-filled polyester concretes
Materials Chemistry and Physics 241 (2020) 122330
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Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys
Photon-shielding performance of bismuth oxychloride-filled polyester concretes Amandeep Sharma a, M.I. Sayyed b, O. Agar c, M.R. Kaçal d, H. Polat e, F. Akman f, g, * a
Department of Physics, Akal University Talwandi Sabo, Bathinda, 151302, India University of Tabuk, Department of Physics, Faculty of Science, Tabuk, Saudi Arabia c Karamano�glu Mehmetbey University, Department of Physics, Karaman, Turkey d Giresun University, Arts and Sciences Faculty, Department of Physics, 28100, Giresun, Turkey e Bing€ ol University, Vocational School of Technical Sciences, Department of Architecture and Urban Planning, 12000, Bing€ ol, Turkey f Bing€ ol University, Vocational School of Social Sciences, Department of Property Protection and Security, Program of Occupational Health and Safety, 12000, Bing€ ol, Turkey g Bing€ ol University, Central Laboratory Application and Research Center, 12000, Bing€ ol, Turkey b
H I G H L I G H T S
� The photon shielding properties for BiClO filled polyester concretes were studied. � The measurements were performed at 22 energies ranging from 59.5 keV to 1408 keV. � The experimental values have been supported with those of XCOM and FLUKA results. � BiClO (20%) has the best radiation shielding property among the selected samples. � These samples are useful for low energy radiation as promising shielding material. A R T I C L E I N F O
A B S T R A C T
Keywords: Polymer concrete Bismuth (III) oxychloride Unsaturated polyester Shielding parameters FLUKA code
The preparation of materials with high attenuation performance is one of the major issues in the radiation shielding applications. This study is based on the investigation of gamma-shielding characteristics of Bismuth (III) Oxychloride (BiClO) doped polymer concretes. In the produced polymer composites, unsaturated polyester, BiClO, methyl ethyl ketone peroxide (MEKP) and cobalt octoate 6% (CO-6) are chosen as resin, filling material, initiators and accelerators, respectively. The radioactive point-isotropic sources 22Na, 54Mn, 57Co, 60Co,133Ba, 137 Cs, 152Eu and 241Am with energies varying from 59.5 keV to 1408.0 keV were used and gamma spectrometer based HPGe detector were employed for the investigation. The obtained experimental data were compared with those of FLUKA code results as well as with XCOM results. We found that the attenuation coefficient values of the studied concretes were in good agreement with the results of other approaches at the investigated energies. BiClO (20%), which is the end-point of compositions studied, has the best radiation shielding property among the prepared polyester concretes. The radiation protection performance of unsaturated polyester resin thus improves with the insertion of BiClO as filler.
1. Introduction Radiation-shielding and protection are among the most crucial issues in many fields i.e., agriculture, industry, research, medical science, and nuclear power plants, etc. To ensure the safety of the public in general as well as the staff that is occupationally exposed to radiation sources in
place of work or laboratory, there should be sufficiently thick shielding material in the surrounding structure so that the radiation is kept at minimum permissible levels. The protection from ionizing radiation is provided by the methods such as the chosen material, the distance from the radiation source and maximum time it is inhabited. The choice and design of shielding materials depend on the type of radiation and its
* Corresponding author. Bing€ ol University, Vocational School of Social Sciences, Department of Property Protection and Security, Program of Occupational Health and Safety, 12000, Bing€ ol, Turkey. E-mail address: [email protected] (F. Akman). https://doi.org/10.1016/j.matchemphys.2019.122330 Received 2 August 2019; Received in revised form 14 October 2019; Accepted 15 October 2019 Available online 18 October 2019 0254-0584/© 2019 Elsevier B.V. All rights reserved.
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intensity. Gamma rays which have very high penetration power are best attenuated by materials with a high atomic number (Z) and high density e.g., lead (Pb) and mercury (Hg). In terms of very large volumes, con cretes are generally considered as most advantageous as far as the cost, ease of handling, flexibility in allowing construction in the desired shape and decommissioning are concerned [1–4]. Recently, heavy-weight concretes are extensively used as a shielding material in various fields namely radio therapy rooms, nuclear power plants, research reactors as well as for storing radioactive wastes. Accordingly, many researchers have reported the development of rein forced concretes for their effective shielding properties [5–11]. Addi tionally, some studies have been carried out on radiation shielding properties of polymers [12], alloys [13–15] and glass materials [16–18]. The development of new materials for effective shielding with reduced heaviness is essentially required in the area of technology. In this context, some authors have explored the polyester based composites as new materials meeting the requirements of gamma radi ation shielding. Harish et al. [19] have used different concentrations, with wt% 0 to 50, of PbO to reinforce the iso-phthalate based composite. The maximum value obtained for the linear attenuation coefficient was 0.206 cm 1on addition of 50 wt % of lead monoxide. Belgin et al. [20] have also reported the performance of low-density polyethylene-based, PbO and WO3 filled, composites as shielding materials and concluded that Pb and W additives enhanced attenuation feature of metal oxide filled polymer. In their study, isophthalic polyester-based composites with five different loadings (10%–50%) of the natural iron mineral as a filler have been reported. The composite with 50% loading of filler was found to be superior to barite, copper and normal aggregate. Similarly, isophthalic based composites with bismuth oxide (Bi2O3) as filler, up to 60% in weight, have been reported by Ambika et al. [21].The authors have performed the measurements at five different gamma-ray energies of 80, 356, 662, 1170 and 1332 keV through a NaI(Tl) scintillation de tector. The evaluated shielding parameters (half-value layer, tenth value layer, and relaxation length) have observed to be decreased with an increase of wt% of filler material. Recently, Bagheri et al. [22] have prepared and characterized unsaturated polyester based composites with nanoclay (wt %: 5) and lead monoxide (wt%: 0, 10, 20, 30) fillers. The authors have reported the mechanical, thermal resistance, tensile testing and shielding features of the prepared composites by employing 137 Cs, 192Ir, and 60Co radioactive sources and found that attenuation coefficient of the composites has increased significantly on the addition of PbO. Keeping in mind the limitations of Pb with its heaviness, high toxicity, low chemical stability, and bremsstrahlung production during electron interaction, it has become a priority to find new materials that can effectively replace conventional shielding materials. In view of this, reinforced unsaturated polyesters, in which Bismuth (III) Oxychloride has been used as filler, have been prepared and examined for their usefulness as an effective shielding material with reduced heaviness. The accurate findings of shielding parameters for newly developed polyester-based concretes are quite useful for the workers to improve their shielding materials. Although experimental findings are considered as final decisionmaking approach for the scientific community, yet the results may be further authenticated with theoretical and simulation-based ap proaches. For the high authenticity of the reported data, three ap proaches (experimental, theoretical and simulation-based) have been utilized in this work for estimation of various shielding related param eters. The experimental measurements have been performed at 22 gamma photon energies (covering a wider range of 59.5 keV–1408 keV) with 59.5 keV as the end-point, by applying high-resolution HPGe de tector. Theoretical computations for the same energy range have been performed by using XCOM standard reference database [23]. Addi tionally, FLUKA-based Monte Carlo simulation results [24] further authenticate the reported measurements on the shielding parameters. Moreover, to the best of our knowledge, FLUKA Monte Carlo code has
been employed as an alternative for the first time in estimating the shielding parameters of newly developed polyester-based composites. The validation provided by FLUKA physics models related to experi mental measurements and XCOM database is a crucial subject of interest that can help to test its applicability for evaluation of shielding param eters of polyester-based concretes. 2. Materials and methods 2.1. Sample preparation process Bismuth (III) Oxychloride (BiClO), purchased from Sigma Aldrich, was inserted as filling material and unsaturated polyester was used as a resin in the produced polymer composites. Methyl ethyl ketone peroxide (MEKP) and Cobalt octoate 6% (CO-6) were included as initiators and accelerators, respectively for the polymer concrete formation process. MEKP and CO-6 were added as 5% and 0.5% of unsaturated polyester resin. Firstly, the necessary materials (filling material, unsaturated polyester, MEKP, and CO-6) were weighed in appropriate amounts using the precision balance. Then, the filler material was added to the unsat urated polyester resin in 5, 10, 15 and 20% by weight. The next step was the mixing process. This continued for 5 min until all the filling mate rials were completely wet. The materials MEKP and CO-6 were added separately to the prepared blend and mixing process continued for 3 min. The obtained mixtures were allowed to harden by placing them according to the molds. The settling time is approximately 20 min inside mold. The samples having 2 cm diameter and 1 cm thickness were ob tained after removing the hardened samples from the molds, and these samples were cured in suitable conditions (air environment and room temperature) for 28 days. Suitable conditions are necessary for a good hardening. Thus, polyester-based concrete samples (Table 1) were ready for the experimental investigations to determine the radiation attenua tion characteristics. 2.2. Experimental and theoretical process in the determination of radiation attenuation property The mass attenuation coefficient values (μ/ρ) of the four polymer concrete samples with different BiClO concentration (5, 10, 15 and 20%) were measured experimentally using the transmission geometry as shown in Fig. 1. The μ/ρ measurements have been carried out using high purity germanium (HPGe) detector at photo-peak energies emitted by the 241Am, 152Eu,137Cs, 133Ba,60Co,57Co, 54Mn and 22Na radioactive point sources. The photo-peak energies from the radioactive point sources have been given in Table 2. The HPGe detector (GEMSP7025P4–B model) has an active crystal diameter of 70 mm, an active crystal length of 25 mm, and resolutions of 380 eV at 5.9 keV, 585 eV at 122 keV and 1.8 keV at 1.33 MeV. More detail on experimental tech nique can be found from our previous studies [13,15,25]. The linear attenuation coefficient (μ, cm 1) of any shielding material is defined from the well-known exponential attenuation (Lambert-Beer) rule [26]: ln II0
μ¼
(1)
x
where I and I0 denote intensities of the transmitted and initial gammarays and x is the thickness (cm) of the polymer concrete sample. The mass attenuation coefficient (μ/ρ, cm2/g) can be found with the help of the linear attenuation coefficient as its ratio to the density of the material considered. The theoretical μ/ρ values for the present polymer concretes were obtained by using mixture rule [27]: μ X �μ� μm ¼ ¼ wi (2)
ρ
ρ
i
where wi is the weight fraction of the ith element in any compound or 2
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Table 1 The elemental compositions and densities of the prepared BiClO concretes. Sample BiClO BiClO BiClO BiClO
Р (g/cm3)
Compositions (%)
(5%) (10%) (15%) (20%)
Co
C
H
O
Bi
Cl
0.0271 0.0260 0.0249 0.0239
56.9947 54.5274 52.2649 50.1826
4.4475 4.2550 4.0785 3.9160
34.2837 33.0655 31.9484 30.9203
3.6309 6.9475 9.9888 12.7878
0.6160 1.1786 1.6946 2.1694
σ t;el: ¼
1 X�μ� fi Ai N i ρ i Zi
1.322 1.383 1.408 1.429
(4)
where Zi and fi are the atomic number and the fractional abundance of the individual element in the polymer concretes, respectively. The effective atomic number (Zeff ), dimensionless quantity, can be obtained from σa and σe: Zeff ¼
Zeff NE ¼ N P i fi Ai
Table 2 Nuclear data on the radioactive point sources used in the measurements. Activity (kBq)
Half life (y)
Energy (keV) –Decay probability (%)
22
456
2.60
54 57
378 413
0.86 0.74
60
424
5.27
460
10.51
511.003 (179.80%) 1274.530 (99.94%) 834.848 (99.98%) 122.061 (85.60%) 136.474 (10.68%) 1173.237 (99.97%) 1332.501 (99.99%) 80.997 (34.06%) 160.613 (0.65%) 276.398 (7.16%) 302.853 (8.33%) 356.017 (62.05%) 383.851 (8.94%) 661.657 (85.10%) 778.9(12.9%) 867.3(4.23%) 964.1(14.51%) 1085.8(10.11%) 1112.1(13.67) 1299.1(1.63%) 1408(20.87%) 59.54 (35.9%)
Na Mn Co Co
133
Ba
137
Cs Eu
152
241
Am
473 370000
460
30.07 13.517
432.2
(5)
Besides, the effective electron density (NE ; electron/g) is closely related to the effective atomic number (Zeff ) and is defined as the number of electrons per unit mass of the interacting materials. For the polymer concretes, NE can be calculated by using the following equation [30]:
Fig. 1. Transmission geometry employing HPGe detector and gamma point sources.
Source
σa σe
(6)
The half-value layer (HVL; cm) defines the thickness at which the transmitted intensity is 50% of the original intensity. Tenth-value layer (TVL; cm) expresses the average amount of material thickness that re duces the radiation to the tenth of the incident intensity (90% reduc tion). HVL and TVL values of the polymer concrete are calculated using the following formula [31]:
μ
(7)
TVL ¼ ln10=
(8)
HVL ¼ ln2=
μ
Furthermore, the mean free path (MFP, cm) denotes the average distance between two successive gamma photon interactions. The (MFP, cm) can be evaluated by using the following equation [32]: MFP ¼ 1=
μ
(9)
The radiation protection efficiency (RPE) of any material is deter mined as follows [33]: � � I RPE ¼ 1 :100 (10) I0
mixture. The μm value of the polymer concrete can be computed for the investigated energy region using XCOM software based on the mixture rule. Furthermore, the μ/ρ quantity is the main tool to obtain many related attenuation quantities such as total atomic and electronic crosssections, tenth and half-value layers [28]. The total atomic cross-section (σt,a) is derived using the following expression: � � μ=ρ σ t;a ¼ P wi (3) N A i Ai
2.3. FLUKA simulation code FLUKA is a Monte Carlo simulation code employed to obtain the radiation shielding parameters for unsaturated polyester based com posites. In addition to the experimental and XCOM database, FLUKA has been used to estimate the attenuation coefficients of reinforced polyester-based composites due to its suitability for selecting better shielding material. FLUKA has the ability to simulate the transportation of more than sixty particles namely photons, neutrons, heavy-ions and electrons in different target materials [34,35]. The provision of designing the simple as well as complex geometries is possible through FLUKA Monte Carlo simulations. A database analysis interface, known as Flair, was used for editing files, code running, obtaining and visuali zation of the desired outputs [36]. In FLUKA there is an input file known as BEAM with the help of which it is convenient to choose the type of transporting particle, its
where NA is the Avogadro number, Ai is the atomic weight of the ith element in the polymer concretes. It is expressed in cm2/atom. The total electronic cross-section (σt,el, cm2/electron) can be obtained as follows [29]: 3
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direction of propagation and starting point as well as the energy of the particle. Input data file for shielding composites were arranged in a typical order as per simulation requirements. A rectangular geometry was designed in the input simulation file, by choosing z-direction as the direction of propagation of gamma photons. A beam with 1x105 parti cles was directed on the polyester-based reinforced composites and attenuated in rectangular parallelepiped (RPP) composites. An RPP is defined by the minimum and maximum limits (in cm) of coordinates which bound the chosen parallelepiped in the following order: Xmin, Xmax, Ymin, Ymax, Zmin, Zmax. In the present simulation work, the coor dinate boundaries were set at Xmin (Ymin) and Xmax (Ymax) 5 cm and þ5 cm respectively as sketched in Fig. 2. This results in 10 cm height and breadth of the target materials with different lengths (thicknesses). The photon transmission results have been obtained using USRBDX score card, after the code was run for 5 cycles, with different sample thick nesses. This scorecard is appropriate to define a detector for estimation of fluence on the boundary between selected regions. The polyesterbased composites have been simulated by a MATERIAL card, in addi tion to desired COMPOUND cards to define a typical composition [24]. The MATERIAL card used to define the desired composition includes the composition name, sequence number, and its density, etc. Other tech nical details have been mentioned in our previous work [18].
well as the input file used in the FLUKA simulation are suitable to report the μ/ρ for the polymer concrete samples with different BiClO concen tration. Moreover, Fig. 4 compares the mass attenuation coefficient of the present samples to other concretes reported by Bashter [37], Agar et al. [38,39]. Obviously, from this figure, the BiClO(20%) sample, which is the end-point of compositions studied, is more effective than all the compared concrete samples. The synthesized sample represents su perior shielding efficiency compared with the five types of concretes displayed in Fig. 4. Obviously as one can notice in Fig. 3, μ/ρ decreases exponentially with the energy (except at 122.1 keV), which agrees with Lambert-Beer law and this trend in the μ/ρ means that the attenuation ability of the samples under evaluation is relatively high at low energy, and the samples can shield more photons, while this ability to shield photons reduces as the energy increases. According to Fig. 3, we can notice that the μ/ρ reaches its highest at the end-point energy of 59.5 keV (0.3780, 0.5480, 0.7070 and 0.8530 cm2/g for concrete polymer with 5, 10, 15 and 20% respectively). The photoelectric phenomenon clearly affects the μ/ρ values at low energy and this explains the quick decrease observed in the μ/ρ values at low energy. As can be seen from Table 3, all the polymer concretes have almost the same μ/ρ values for 1112.1 keV < E < 1408 keV and this is attributed to Compton scattering. Besides, an increase in μ/ρ is observed with increase in the concentration of BiClO. This increase occurs since the bismuth is a heavy element (Z ¼ 83) and it is known that the heavy elements are preferable for shielding application. The linear attenuation coefficients (μ) at the investigated energies shown in Fig. 5, also show a decreasing trend (except at 122.1 keV) and the highest μ values for all the samples with different BiClO content are found at the end-point of 59.5 keV, to be 0.5000, 0.7580, 0.9949 and 1.2190 cm 1 for 5, 10, 15 and 20 wt% of BiClO, respectively. Also, the addition of BiClO content leads to an increase in the μ values at all the energies and this is in agreement with the previous curve. The radiation protection efficiency (RPE) is another way to estimate the number of photons that can penetrate the attenuator material and thus, gives an indication about the number of photons that can be blocked or attenuated from the polymer concrete sample. The intensities of original and transmitting photons guided us to calculate the RPE for the polymer concretes with 5, 10, 15 and 20 wt% BiClO content at the investigated energies (between 59.5 keV and 1408 keV) and the results have been plotted in Fig. 6. The maximum RPE for the prepared polymer concretes occurs at the lowest energy 59.5 keV and is equal to 72.04% for the sample with 20 wt% of BiClO content, which is the end-point of compositions studied. It can be observed from the RPE curve that the polymer concrete samples have high attenuation capability at low en ergy. For example, at the end-point of 59.5 keV, BiClO(20%) the sample can shield 72.04% of the incoming photons and thus only 27.96% of the photons can penetrate through this sample. From Fig. 6, we can also notice that the RPE decreases with the increase in energy and this is expected according to the results shown by the previous parameter. Moreover, it is found that the RPE of BiClO(20%) sample, which is the end-point of compositions studied, is higher than the RPE of the remaining concretes. This higher RPE for this concrete polymer sample is due to the higher content of Bi. This signifies that BiClO(20%) pro vides better attenuation of gamma photons. Additionally, the RPE re sults show that above 1085.8 keV energy, all the prepared samples have almost the same RPE values. For example, the RPE for BiClO(5%) and BiClO(20%) samples at 1212.9 keV are 8.79 and 8.88% respectively. From the RPE results, we can conclude that the BiClO(20%), which is the end-point of compositions studied, has superior attenuating perfor mance than the other polymer concrete samples, and all these materials are more efficacious for attenuating the low energy photons. The exact attenuator thickness needed for diminishing the photons intensity to exactly one-half of the original values can be represented by the half-value layer (HVL). This thickness depends inversely on the density of the sample. The data regarding the HVL for the prepared
3. Results and discussion The μ/ρ values of the four polymer concrete samples with different Bi concentration (5%, 10%, 15%, and 20%) were measured experimentally as illustrated in section 2. Moreover, to validate the experimental setup used in the present investigation, the μ/ρ of these polymer concretes were simulated using Monte Carlo code based FLUKA and was evaluated theoretically by XCOM database. The experimental, FLUKA and XCOM based mass attenuation coefficient values of the prepared polymer concretes at twenty-two energies (59.5 keV–1408 keV) are collected and summarized in Table 3 and plotted in Fig. 3. From the data presented in the table, we can deduce that the agreement between measured, simu lated and XCOM based μ/ρ results is extremely acceptable. For instance, for BiClO (5%) at 59.5 keV (very low energy) the measured value is 0.3787 cm2/g, which is very close to the FLUKA value (0.3762 cm2/g) and XCOM value (0.3780 cm2/g). For the same sample at 1112.1 keV (as an example), the measured value is reported as 0.0610 cm2/g, while the FLUKA and XCOM values are 0.0631 and 0.0632 cm2/g respectively. For all the other samples and the investigated energy values, the measured μ/ρ values agree well with the FLUKA and XCOM. From this, we can surely assume that the present setup used for the μ/ρ measurements as
Fig. 2. Sketch of simulated geometry chosen through Flair. 4
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Table 3 Comparison of experimental, XCOM and FLUKA based mass attenuation coefficients of the investigated polyester concretes. Energy (keV)
59.5 80.9 122.1 136.4 276.3 302.8 356.0 383.8 511.0 661.6 778.9 834.8 867.3 964.1 1085.8 1112.1 1173.2 1212.9 1274.5 1299.1 1332.5 1408.0
Mass attenuation coefficients (cm2/g) BiClO (5%)
BiClO (10%)
BiClO (15%)
BiClO (20%)
Exp.
XCOM
FLUKA
Exp.
XCOM
FLUKA
Exp.
XCOM
FLUKA
Exp.
XCOM
FLUKA
0.3787 � 0.0078 0.2539 � 0.0052 0.2798 � 0.0062 0.2467 � 0.0131 0.1258 � 0.0046 0.1189 � 0.0029 0.1067 � 0.0022 0.1020 � 0.0033 0.0944 � 0.0019 0.0804 � 0.0017 0.0749 � 0.0020 0.0711 � 0.0018 0.0729 � 0.0028 0.0656 � 0.0015 0.0643 � 0.0017 0.0610 � 0.0013 0.0604 � 0.0013 0.0591 � 0.0030 0.0616 � 0.0013 0.0574 � 0.0022 0.0569 � 0.0012 0.0530 � 0.0011
0.3780 0.2530 0.2720 0.2360 0.1290 0.1220 0.1120 0.1070 0.0929 0.0819 0.0756 0.0730 0.0717 0.0680 0.0640 0.0632 0.0615 0.0604 0.0589 0.0583 0.0575 0.0559
0.3762 0.2516 0.2718 0.2360 0.1286 0.1172 0.1108 0.1072 0.0925 0.0819 0.0756 0.0724 0.0715 0.0673 0.0643 0.0631 0.0617 0.0605 0.0588 0.0581 0.0576 0.0558
0.5710 � 0.0118 0.3449 � 0.0070 0.3690 � 0.0080 0.3127 � 0.0155 0.1371 � 0.0051 0.1274 � 0.0031 0.1182 � 0.0025 0.1152 � 0.0040 0.0965 � 0.0020 0.0798 � 0.0016 0.0780 � 0.0021 0.0751 � 0.0019 0.0707 � 0.0026 0.0662 � 0.0015 0.0642 � 0.0016 0.0611 � 0.0013 0.0644 � 0.0014 0.0598 � 0.0028 0.0615 � 0.0013 0.0600 � 0.0022 0.0557 � 0.0012 0.0545 � 0.0011
0.5480 0.3280 0.3810 0.3170 0.1410 0.1320 0.1180 0.1120 0.0951 0.0829 0.0761 0.0734 0.0720 0.0682 0.0641 0.0633 0.0615 0.0604 0.0588 0.0583 0.0575 0.0558
0.5480 0.3249 0.3809 0.3180 0.1415 0.1313 0.1174 0.1118 0.0949 0.0827 0.0759 0.0734 0.0720 0.0679 0.0642 0.0632 0.0612 0.0602 0.0589 0.0582 0.0574 0.0558
0.6784 � 0.0143 0.4148 � 0.0086 0.4709 � 0.0108 0.4115 � 0.0224 0.1458 � 0.0048 0.1437 � 0.0036 0.1261 � 0.0026 0.1167 � 0.0037 0.0998 � 0.0021 0.0851 � 0.0017 0.0766 � 0.0020 0.0747 � 0.0018 0.0743 � 0.0029 0.0663 � 0.0015 0.0623 � 0.0016 0.0635 � 0.0014 0.0605 � 0.0013 0.0593 � 0.0028 0.0576 � 0.0012 0.0567 � 0.0020 0.0598 � 0.0012 0.0561 � 0.0012
0.7070 0.3980 0.4820 0.3940 0.1530 0.1410 0.1240 0.1170 0.0972 0.0838 0.0767 0.0738 0.0723 0.0683 0.0641 0.0633 0.0615 0.0604 0.0588 0.0582 0.0574 0.0558
0.6983 0.3954 0.4681 0.3923 0.1520 0.1406 0.1300 0.1166 0.0973 0.0834 0.0764 0.0739 0.0722 0.0684 0.0639 0.0631 0.0614 0.0601 0.0586 0.0581 0.0575 0.0557
0.8273 � 0.0181 0.4819 � 0.0104 0.5946 � 0.0154 0.4423 � 0.0250 0.1656 � 0.0055 0.1440 � 0.0035 0.1253 � 0.0026 0.1175 � 0.0043 0.0946 � 0.0019 0.0848 � 0.0017 0.0809 � 0.0021 0.0725 � 0.0018 0.0746 � 0.0029 0.0688 � 0.0015 0.0633 � 0.0016 0.0616 � 0.0013 0.0638 � 0.0013 0.0604 � 0.0030 0.0572 � 0.0012 0.0559 � 0.0022 0.0562 � 0.0012 0.0548 � 0.0011
0.8530 0.4630 0.5760 0.4640 0.1640 0.1490 0.1290 0.1210 0.0991 0.0847 0.0771 0.0742 0.0726 0.0685 0.0642 0.0633 0.0615 0.0604 0.0588 0.0582 0.0574 0.0557
0.8455 0.4561 0.5762 0.4631 0.1593 0.1484 0.1281 0.1218 0.0989 0.0844 0.0768 0.0739 0.0725 0.0682 0.0638 0.0632 0.0615 0.0603 0.0587 0.0582 0.0571 0.0555
Fig. 3. The experimental, FLUKA and XCOM based mass attenuation coefficients for the BiClO filler composites.
5
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Fig. 4. The mass attenuation coefficients of the prepared polyester concretes in comparison to some standard and different concretes. Fig. 6. Comparison of radiation protection efficiency (RPE) for the prepared concretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
Fig. 5. Comparison of linear attenuation coefficients for the prepared concretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
polymer concretes with different BiClO content are presented graphi cally in Fig. 7. Apparently, as the energy changes from 59.5 keV to 1408 keV, the HVL values show an increase. This result implies that increasing the energy of the photons makes the photons capable of sharply penetrating through the polymer concretes under evaluation. The results also showed that the HVL for the highest density polymer concrete sample namely BiClO(20%) is lower than other samples (BiClO (5%), BiClO(10%) and BiClO(15%)), while BiClO(5%) which possesses the lowest weight fraction of Bi and thus the lowest density (ρ ¼ 1.322 g/ cm3) has the highest HVL values. For instance, at 136.4 keV, the thick ness of BiClO(5%) is 2.220 cm to decrease the photon intensity to 50%, while BiClO(20%) needs to be 1.046 cm thick for the same reduction. Moreover, the HVL for the same two samples at 1112 keV is 8.294 cm and 7.658 cm respectively. These findings show how the shielding per formance of the prepared polymer concretes with different BiClO con tent is highly inversely proportional to the density. The same HVL dependence of the density was found for other materials such as alloys [14,15] and glasses [40]. Therefore, we can state that increasing the Bi content leads to an increase in the density of the prepared polymer concrete samples and this leads to improvisation of the
Fig. 7. Comparison of half value layer (HVL) for the prepared concretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
photons-attenuating ability of the investigated polymer concretes. Figs. 8 and 9 present other two valuable parameters usually used to estimate the photons attenuation performance of different materials. These two parameters are the tenth value layer (TVL) and mean free path (MFP). It is important to state that lower TVL and MFP values imply more interactions between photons and the prepared polymer concretes; hence the attenuating efficiency is better. According to the analysis of both parameters for the polymer concretes, the TVL and MFP were increased quickly as a function of the energy. In other words, the results of these two parameters were very similar to those found for the HVL presented in the previous figure. It should be noted that the TVL and MFP values were decreased with increase in the density of the polymer concretes. For example, as the density increases from 1.322 to 1.429 g/cm3, the TVL decreases from 7.062 to 3.644 cm (this is at 136.4 keV). Also, at 383.8 keV and for the same two samples, the MFP decreases from 17.083 to 13.715 cm. Similar 6
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Fig. 8. Comparison of tenth value layer (TVL) for the prepared concretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
Fig. 10. Comparison of effective atomic number (Zeff) for the prepared con cretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
Fig. 9. Comparison of mean free path (MFP) for the prepared concretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
Fig. 11. Comparison of effective electron density (NE) for the prepared con cretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
dependences of the TVL as well as MFP on the density are also reported for glasses [41] and concretes [39]. Figs. 10 and 11 show the calculated Zeff and NE values for four polymer concrete samples with different BiClO concentration (5, 10, 15 and 20%) as a function of the energy. It is obvious that Zeff and NE values decreased with the increase in the energy from 59.5 keV to 1408 keV (except at 122.1 keV), but this trend was most pronounced at low en ergies where the photoelectric effect dominated. The Zeff values for BiClO(5%), BiClO(10%), BiClO(15%) and BiClO(20%) are respectively in the range 9.0205–4.6052, 12.8729-4.7808, 16.3812-4.9585, 19.5261-5.1343. Considering the changes in the weight fractions of the constituent elements for the prepared polymer concretes, the Zeff for BiClO(20%), which is the end-point of compositions studied, is higher than the other samples under evaluation, whereas BiClO(5%) possesses the lowest Zeff. The weight fraction of oxygen (Z ¼ 8), carbon (Z ¼ 6), bismuth (Z ¼ 83) in BiClO(5%) are 34.2837, 56.9947 and 3.6309% respectively, while for BiClO(20%) they are 30.9203%, 50.1826%, and
12.7878%; i.e., as the Bi content increases in the BiClO(20%) sample, the amount of oxygen and carbon decrease and this leads to an increase in the Zeff. Taking into account the Zeff results presented in Fig. 10, the BiClO(20%) can shield photons better than other concrete polymers which were used in this investigation. It can be noticed from Fig. 11 that the NE follows the order: BiClO(20%)> BiClO(15%)> BiClO(10%)> BiClO(5%). This means that an addition of BiClO increases the NE values and this is due to the dependence of this parameter on the Zeff. Similar results were found in the literature for other materials such as glasses [42] where the NE has similar behavior with Zeff. 4. Conclusions This paper focused on estimating the appropriate experimental, XCOM and FLUKA results in terms of gamma attenuation features for concretes including unsaturated polyester at various energies between 59.5 keV and 1408 keV. The following conclusions can be drawn from 7
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the study:
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Tekin, Investigation of photon shielding performances of some selected alloys by experimental data, theoretical and MCNPX code in the energy range of 81 keV–1333 keV, J. Alloy. Comp. (2019), https://doi.org/10.1016/j.jallcom.2018.09.177. [16] H.O. Tekin, M.I. Sayyed, T. Manici, E.E. Altunsoy, Photon shielding characterizations of bismuth modified borate –silicate–tellurite glasses using MCNPX Monte Carlo code, Mater. Chem. Phys. 211 (2018) 9–16, https://doi.org/ 10.1016/j.matchemphys.2018.02.009. [17] M.I. Sayyed, K.M. Kaky, E. S¸akar, U. Akbaba, M.M. Taki, O. Agar, Gamma radiation shielding investigations for selected germanate glasses, J. Non-Cryst. Solids 512 (2019) 33–40, https://doi.org/10.1016/j.jnoncrysol.2019.02.014. [18] A. Sharma, M.I. Sayyed, O. Agar, H.O. Tekin, Simulation of shielding parameters for TeO2-WO3-GeO2 glasses using FLUKA code, Results Phys 13 (2019) 102199, https://doi.org/10.1016/j.rinp.2019.102199. [19] V. Harish, N. Nagaiah, T.N. Prabhu, K.T. Varughese, Preparation and characterization of lead monoxide filled unsaturated polyester based polymer composites for gamma radiation shielding applications, J. Appl. Polym. Sci. 112 (3) (2009) 1503–1508, https://doi.org/10.1002/app.29633. [20] E. Eren Belgin, G.A. Aycik, Preparation and radiation attenuation performances of metal oxide filled polyethylene based composites for ionizing electromagnetic radiation shielding applications, J. Radioanal. Nucl. Chem. 306 (1) (2015) 107–117, https://doi.org/10.1007/s10967-015-4052-2. [21] M.R. Ambika, N. Nagaiah, S.K. Suman, Role of bismuth oxide as a reinforcer on gamma shielding ability of unsaturated polyester based polymer composites, J. Appl. Polym. Sci. 134 (2017) 13, https://doi.org/10.1002/app.44657. [22] K. Bagheri, S.M. Razavi, S.J. Ahmadi, M. Kosari, H. Abolghasemi, Thermal resistance, tensile properties, and gamma radiation shielding performance of unsaturated polyester/nanoclay/PbO composites, Radiat. Phys. Chem. 146 (2018) 5–10, https://doi.org/10.1016/j.radphyschem.2017.12.024. [23] M. Berger, J. Hubbell, S. Seltzer, J. Chang, J. Coursey, R. Sukumar, D. Zucker, K. Olsen, XCOM: photon cross sections database, NIST Stand. Ref. Database 8 (XGAM). (1998) citeulike-article-id:9783715. [24] A. Ferrari, Others, FLUKA: A Multi-Particle Transport Code (Program Version 2005), 2005, https://doi.org/10.5170/cern-2005-010. Cern-2005-010. [25] F. Akman, O. Agar, M.R. Kaçal, M.I. Sayyed, Comparison of experimental and theoretical radiation shielding parameters of several environmentally friendly materials, Nucl. Sci. Tech. 30 (7) (2019) 110, https://doi.org/10.1007/s41365019-0631-1. [26] C. Eke, O. Agar, C. Segebade, I. Boztosun, Attenuation properties of radiation shielding materials such as granite and marble against γ-ray energies between 80 and 1350 keV, Radiochim. Acta 105 (10) (2017) 851–863, https://doi.org/ 10.1515/ract-2016-2690. [27] F. Akman, R. Durak, M.F. Turhan, M.R. Kaçal, Studies on effective atomic numbers, electron densities from mass attenuation coefficients near the K edge in some samarium compounds, Appl. Radiat. Isot. 101 (2015) 107–113, https://doi.org/ 10.1016/j.apradiso.2015.04.001. [28] M.G. Dong, O. Agar, H.O. Tekin, O. Kilicoglu, K.M. Kaky, M.I. Sayyed, A comparative study on gamma photon shielding features of various germanate glass systems, Compos. B Eng. 165 (2019) 636–647, https://doi.org/10.1016/j. compositesb.2019.02.022. [29] A.M. El-Khayatt, Calculation of fast neutron removal cross-sections for some compounds and materials, Ann. Nucl. Energy 37 (2) (2010) 218–222, https://doi. org/10.1016/j.anucene.2009.10.022. [30] H.O. Tekin, E. Kavaz, E.E. Altunsoy, O. Kilicoglu, O. Agar, T.T. Erguzel, M. I. Sayyed, An extensive investigation on gamma-ray and neutron attenuation parameters of cobalt oxide and nickel oxide substituted bioactive glasses, Ceram. Int. (2019) 1–16, https://doi.org/10.1016/j.ceramint.2019.02.036. [31] H.C. Manjunatha, L. Seenappa, B.M. Chandrika, K.N. Sridhar, C. Hanumantharayappa, Gamma, X-ray and neutron shielding parameters for the Al-based glassy alloys, Appl. Radiat. Isot. 139 (2018) 187–194, https://doi.org/ 10.1016/j.apradiso.2018.05.014. [32] N.S. Prabhu, V. Hegde, M.I. Sayyed, O. Agar, S.D. Kamath, Investigations on structural and radiation shielding properties of Er3þ doped zinc bismuth borate glasses, Mater. Chem. Phys. 230 (2019) 267–276, https://doi.org/10.1016/j. matchemphys.2019.03.074. [33] A. Kumar, Gamma ray shielding properties of PbO-Li2O-B2O3glasses, Radiat. Phys. Chem. 136 (2017) 50–53, https://doi.org/10.1016/j.radphyschem.2017.03.023. [34] G. Battistoni, T. Boehlen, F. Cerutti, P.W. Chin, L.S. Esposito, A. Fass� o, A. Ferrari, A. Lechner, A. Empl, A. Mairani, A. Mereghetti, P.G. Ortega, J. Ranft, S. Roesler, P. R. Sala, V. Vlachoudis, G. Smirnov, Overview of the FLUKA code, Ann. Nucl. Energy 82 (2015) 10–18, https://doi.org/10.1016/j.anucene.2014.11.007. 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� To ensure higher accuracy in shielding effectiveness, the experi mental values have been supported with those of XCOM database and FLUKA Monte Carlo code results. � FLUKA has been employed as an alternative in estimating the radi ation shielding parameters of polyester-based concretes for the first time. � It has been observed that BiClO (20%) concrete, which is the endpoint of compositions studied, containing a high amount of Bi consistently possesses the best photon-shielding performance in comparison to other samples. � The encouraging finding emphasizes the relevance of using com posite with the insertion of BiClO content to attenuate photon more. Accordingly, such concretes maybe useful for low-energy ionizing radiation as promising shielding absorber. In addition, the unsatu rated polyester, being a quite light material, can be conveniently put into a number of uses, namely storage and transportation, when compared to other materials. � The usage of eco-friendly BiClO based concretes may be utilized to protect people and equipment operating in hospitals and medical centers, shielding of reactors, storage of radioactive waste products, rooms with radiation emitting devices from ionizing radiation. Moreover, it is anticipated that the use of Pb-doped materials with too much toxic effect, high cost and heaviness for transportation and storage will be reduced. � The present results are expected to be useful in dosimetry, radiation shielding, and other radiation-related fields. Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi. org/10.1016/j.matchemphys.2019.122330. References [1] W.R. Leo, Techniques for Nuclear and Particle Physics Experiments, SpringerVerlag Berlin Heidelberg, 1994, https://doi.org/10.1007/978-3-642-57920-2. [2] O. Gencel, W. Brostow, C. Ozel, M. Filiz, An investigation on the concrete properties containing colemanite, Int. J. Phys. Sci. 5 (3) (2010) 216–225. [3] O. Gencel, The application of artificial neural networks technique to estimate mass attenuation coefficient of shielding barrier, Int. J. Phys. Sci. 4 (12) (2009) 743–751. [4] O. Gencel, A. Bozkurt, E. Kam, T. Korkut, Determination and calculation of gamma and neutron shielding characteristics of concretes containing different hematite proportions, Ann. Nucl. Energy 38 (12) (2011) 2719–2723, https://doi.org/ 10.1016/j.anucene.2011.08.010. [5] N.R. Abd Elwahab, N. Helal, T. Mohamed, F. Shahin, F.M. Ali, New shielding composite paste for mixed fields of fast neutrons and gamma rays, Mater. Chem. Phys. 233 (2019) 249–253, https://doi.org/10.1016/j.matchemphys.2019.05.059. [6] R. Bagheri, A.K. Moghaddam, A. Yousefi, Gamma-ray shielding study of light to heavyweight concretes using MCNP-4C code, Nucl. Sci. Tech. 28 (2) (2017) 15, https://doi.org/10.1007/s41365-016-0167-6. € Kılıço� [7] O. glu, H.O. Tekin, V.P. Singh, Determination of mass attenuation coefficients of different types of concretes using Monte Carlo method, Eur. J. Sci. Technol. (2019) 591–598, https://doi.org/10.31590/ejosat.535203. [8] S.S. Obaid, D.K. Gaikwad, P.P. Pawar, Determination of gamma ray shielding parameters of rocks and concrete, Radiat. Phys. Chem. 144 (2018) 356–360, https://doi.org/10.1016/j.radphyschem.2017.09.022. [9] M. Çelikbilek Ersundu, A.E. Ersundu, M.I. Sayyed, G. Lakshminarayana, S. Aydin, Evaluation of physical, structural properties and shielding parameters for K2O–WO3–TeO2glasses for gamma ray shielding applications, J. Alloy. Comp. 714 (2017) 278–286, https://doi.org/10.1016/j.jallcom.2017.04.223. [10] M.I. Sayyed, H.O. Tekin, O. Kılıcoglu, O. Agar, M.H.M. Zaid, Shielding features of concrete types containing sepiolite mineral: comprehensive study on experimental, XCOM and MCNPX results, Results Phys 11 (2018), https://doi.org/10.1016/j. rinp.2018.08.029.
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challenges for high energy and medical applications, Nucl. Data Sheets 120 (2014) 211–214, https://doi.org/10.1016/j.nds.2014.07.049. V. Vlachoudis, FLAIR: a powerful but user friendly graphical interface for FLUKA, Proc. Int. Conf. Math. Comput. (2009), https://doi.org/10.1016/S1473-3099(14) 71090-4. I.I. Bashter, Calculation of radiation attenuation coefficients for shielding concretes, Ann. Nucl. Energy 24 (1997) 1389–1401, https://doi.org/10.1016/ S0306-4549(97)00003-0. O. Agar, Study on gamma ray shielding performance of concretes doped with natural sepiolite mineral, Radiochim. Acta 106 (2018) 1009–1016, https://doi. org/10.1515/ract-2018-2981. O. Agar, H.O. Tekin, M.I. Sayyed, M.E. Korkmaz, O. Culfa, C. Ertugay, Experimental investigation of photon attenuation behaviors for concretes including
natural perlite mineral, Results Phys 12 (2019) 237–243, https://doi.org/10.1016/ j.rinp.2018.11.053. [40] O. Agar, Z.Y. Khattari, M.I. Sayyed, H.O. Tekin, S. Al-Omari, M. Maghrabi, M.H. M. Zaid, I.V. Kityk, Evaluation of the shielding parameters of alkaline earth based phosphate glasses using MCNPX code, Results Phys 12 (2019) 101–106, https:// doi.org/10.1016/j.rinp.2018.11.054. [41] A. Kumar, M.I. Sayyed, M. Dong, X. Xue, Effect of PbO on the shielding behavior of ZnO–P2O5 glass system using Monte Carlo simulation, J. Non-Cryst. Solids 481 (2018) 604–607, https://doi.org/10.1016/j.jnoncrysol.2017.12.001. [42] M.I. Sayyed, G. Lakshminarayana, M.G. Dong, M.Ç. Ersundu, A.E. Ersundu, I. V. Kityk, Investigation on gamma and neutron radiation shielding parameters for BaO/SrO‒Bi 2 O 3 ‒B 2 O 3 glasses, Radiat. Phys. Chem. 145 (2018) 26–33, https://doi.org/10.1016/j.radphyschem.2017.12.010.
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Photon-shielding performance of bismuth oxychloride-filled polyester concretes Amandeep Sharma a, M.I. Sayyed b, O. Agar c, M.R. Kaçal d, H. Polat e, F. Akman f, g, * a
Department of Physics, Akal University Talwandi Sabo, Bathinda, 151302, India University of Tabuk, Department of Physics, Faculty of Science, Tabuk, Saudi Arabia c Karamano�glu Mehmetbey University, Department of Physics, Karaman, Turkey d Giresun University, Arts and Sciences Faculty, Department of Physics, 28100, Giresun, Turkey e Bing€ ol University, Vocational School of Technical Sciences, Department of Architecture and Urban Planning, 12000, Bing€ ol, Turkey f Bing€ ol University, Vocational School of Social Sciences, Department of Property Protection and Security, Program of Occupational Health and Safety, 12000, Bing€ ol, Turkey g Bing€ ol University, Central Laboratory Application and Research Center, 12000, Bing€ ol, Turkey b
H I G H L I G H T S
� The photon shielding properties for BiClO filled polyester concretes were studied. � The measurements were performed at 22 energies ranging from 59.5 keV to 1408 keV. � The experimental values have been supported with those of XCOM and FLUKA results. � BiClO (20%) has the best radiation shielding property among the selected samples. � These samples are useful for low energy radiation as promising shielding material. A R T I C L E I N F O
A B S T R A C T
Keywords: Polymer concrete Bismuth (III) oxychloride Unsaturated polyester Shielding parameters FLUKA code
The preparation of materials with high attenuation performance is one of the major issues in the radiation shielding applications. This study is based on the investigation of gamma-shielding characteristics of Bismuth (III) Oxychloride (BiClO) doped polymer concretes. In the produced polymer composites, unsaturated polyester, BiClO, methyl ethyl ketone peroxide (MEKP) and cobalt octoate 6% (CO-6) are chosen as resin, filling material, initiators and accelerators, respectively. The radioactive point-isotropic sources 22Na, 54Mn, 57Co, 60Co,133Ba, 137 Cs, 152Eu and 241Am with energies varying from 59.5 keV to 1408.0 keV were used and gamma spectrometer based HPGe detector were employed for the investigation. The obtained experimental data were compared with those of FLUKA code results as well as with XCOM results. We found that the attenuation coefficient values of the studied concretes were in good agreement with the results of other approaches at the investigated energies. BiClO (20%), which is the end-point of compositions studied, has the best radiation shielding property among the prepared polyester concretes. The radiation protection performance of unsaturated polyester resin thus improves with the insertion of BiClO as filler.
1. Introduction Radiation-shielding and protection are among the most crucial issues in many fields i.e., agriculture, industry, research, medical science, and nuclear power plants, etc. To ensure the safety of the public in general as well as the staff that is occupationally exposed to radiation sources in
place of work or laboratory, there should be sufficiently thick shielding material in the surrounding structure so that the radiation is kept at minimum permissible levels. The protection from ionizing radiation is provided by the methods such as the chosen material, the distance from the radiation source and maximum time it is inhabited. The choice and design of shielding materials depend on the type of radiation and its
* Corresponding author. Bing€ ol University, Vocational School of Social Sciences, Department of Property Protection and Security, Program of Occupational Health and Safety, 12000, Bing€ ol, Turkey. E-mail address: [email protected] (F. Akman). https://doi.org/10.1016/j.matchemphys.2019.122330 Received 2 August 2019; Received in revised form 14 October 2019; Accepted 15 October 2019 Available online 18 October 2019 0254-0584/© 2019 Elsevier B.V. All rights reserved.
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intensity. Gamma rays which have very high penetration power are best attenuated by materials with a high atomic number (Z) and high density e.g., lead (Pb) and mercury (Hg). In terms of very large volumes, con cretes are generally considered as most advantageous as far as the cost, ease of handling, flexibility in allowing construction in the desired shape and decommissioning are concerned [1–4]. Recently, heavy-weight concretes are extensively used as a shielding material in various fields namely radio therapy rooms, nuclear power plants, research reactors as well as for storing radioactive wastes. Accordingly, many researchers have reported the development of rein forced concretes for their effective shielding properties [5–11]. Addi tionally, some studies have been carried out on radiation shielding properties of polymers [12], alloys [13–15] and glass materials [16–18]. The development of new materials for effective shielding with reduced heaviness is essentially required in the area of technology. In this context, some authors have explored the polyester based composites as new materials meeting the requirements of gamma radi ation shielding. Harish et al. [19] have used different concentrations, with wt% 0 to 50, of PbO to reinforce the iso-phthalate based composite. The maximum value obtained for the linear attenuation coefficient was 0.206 cm 1on addition of 50 wt % of lead monoxide. Belgin et al. [20] have also reported the performance of low-density polyethylene-based, PbO and WO3 filled, composites as shielding materials and concluded that Pb and W additives enhanced attenuation feature of metal oxide filled polymer. In their study, isophthalic polyester-based composites with five different loadings (10%–50%) of the natural iron mineral as a filler have been reported. The composite with 50% loading of filler was found to be superior to barite, copper and normal aggregate. Similarly, isophthalic based composites with bismuth oxide (Bi2O3) as filler, up to 60% in weight, have been reported by Ambika et al. [21].The authors have performed the measurements at five different gamma-ray energies of 80, 356, 662, 1170 and 1332 keV through a NaI(Tl) scintillation de tector. The evaluated shielding parameters (half-value layer, tenth value layer, and relaxation length) have observed to be decreased with an increase of wt% of filler material. Recently, Bagheri et al. [22] have prepared and characterized unsaturated polyester based composites with nanoclay (wt %: 5) and lead monoxide (wt%: 0, 10, 20, 30) fillers. The authors have reported the mechanical, thermal resistance, tensile testing and shielding features of the prepared composites by employing 137 Cs, 192Ir, and 60Co radioactive sources and found that attenuation coefficient of the composites has increased significantly on the addition of PbO. Keeping in mind the limitations of Pb with its heaviness, high toxicity, low chemical stability, and bremsstrahlung production during electron interaction, it has become a priority to find new materials that can effectively replace conventional shielding materials. In view of this, reinforced unsaturated polyesters, in which Bismuth (III) Oxychloride has been used as filler, have been prepared and examined for their usefulness as an effective shielding material with reduced heaviness. The accurate findings of shielding parameters for newly developed polyester-based concretes are quite useful for the workers to improve their shielding materials. Although experimental findings are considered as final decisionmaking approach for the scientific community, yet the results may be further authenticated with theoretical and simulation-based ap proaches. For the high authenticity of the reported data, three ap proaches (experimental, theoretical and simulation-based) have been utilized in this work for estimation of various shielding related param eters. The experimental measurements have been performed at 22 gamma photon energies (covering a wider range of 59.5 keV–1408 keV) with 59.5 keV as the end-point, by applying high-resolution HPGe de tector. Theoretical computations for the same energy range have been performed by using XCOM standard reference database [23]. Addi tionally, FLUKA-based Monte Carlo simulation results [24] further authenticate the reported measurements on the shielding parameters. Moreover, to the best of our knowledge, FLUKA Monte Carlo code has
been employed as an alternative for the first time in estimating the shielding parameters of newly developed polyester-based composites. The validation provided by FLUKA physics models related to experi mental measurements and XCOM database is a crucial subject of interest that can help to test its applicability for evaluation of shielding param eters of polyester-based concretes. 2. Materials and methods 2.1. Sample preparation process Bismuth (III) Oxychloride (BiClO), purchased from Sigma Aldrich, was inserted as filling material and unsaturated polyester was used as a resin in the produced polymer composites. Methyl ethyl ketone peroxide (MEKP) and Cobalt octoate 6% (CO-6) were included as initiators and accelerators, respectively for the polymer concrete formation process. MEKP and CO-6 were added as 5% and 0.5% of unsaturated polyester resin. Firstly, the necessary materials (filling material, unsaturated polyester, MEKP, and CO-6) were weighed in appropriate amounts using the precision balance. Then, the filler material was added to the unsat urated polyester resin in 5, 10, 15 and 20% by weight. The next step was the mixing process. This continued for 5 min until all the filling mate rials were completely wet. The materials MEKP and CO-6 were added separately to the prepared blend and mixing process continued for 3 min. The obtained mixtures were allowed to harden by placing them according to the molds. The settling time is approximately 20 min inside mold. The samples having 2 cm diameter and 1 cm thickness were ob tained after removing the hardened samples from the molds, and these samples were cured in suitable conditions (air environment and room temperature) for 28 days. Suitable conditions are necessary for a good hardening. Thus, polyester-based concrete samples (Table 1) were ready for the experimental investigations to determine the radiation attenua tion characteristics. 2.2. Experimental and theoretical process in the determination of radiation attenuation property The mass attenuation coefficient values (μ/ρ) of the four polymer concrete samples with different BiClO concentration (5, 10, 15 and 20%) were measured experimentally using the transmission geometry as shown in Fig. 1. The μ/ρ measurements have been carried out using high purity germanium (HPGe) detector at photo-peak energies emitted by the 241Am, 152Eu,137Cs, 133Ba,60Co,57Co, 54Mn and 22Na radioactive point sources. The photo-peak energies from the radioactive point sources have been given in Table 2. The HPGe detector (GEMSP7025P4–B model) has an active crystal diameter of 70 mm, an active crystal length of 25 mm, and resolutions of 380 eV at 5.9 keV, 585 eV at 122 keV and 1.8 keV at 1.33 MeV. More detail on experimental tech nique can be found from our previous studies [13,15,25]. The linear attenuation coefficient (μ, cm 1) of any shielding material is defined from the well-known exponential attenuation (Lambert-Beer) rule [26]: ln II0
μ¼
(1)
x
where I and I0 denote intensities of the transmitted and initial gammarays and x is the thickness (cm) of the polymer concrete sample. The mass attenuation coefficient (μ/ρ, cm2/g) can be found with the help of the linear attenuation coefficient as its ratio to the density of the material considered. The theoretical μ/ρ values for the present polymer concretes were obtained by using mixture rule [27]: μ X �μ� μm ¼ ¼ wi (2)
ρ
ρ
i
where wi is the weight fraction of the ith element in any compound or 2
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Table 1 The elemental compositions and densities of the prepared BiClO concretes. Sample BiClO BiClO BiClO BiClO
Р (g/cm3)
Compositions (%)
(5%) (10%) (15%) (20%)
Co
C
H
O
Bi
Cl
0.0271 0.0260 0.0249 0.0239
56.9947 54.5274 52.2649 50.1826
4.4475 4.2550 4.0785 3.9160
34.2837 33.0655 31.9484 30.9203
3.6309 6.9475 9.9888 12.7878
0.6160 1.1786 1.6946 2.1694
σ t;el: ¼
1 X�μ� fi Ai N i ρ i Zi
1.322 1.383 1.408 1.429
(4)
where Zi and fi are the atomic number and the fractional abundance of the individual element in the polymer concretes, respectively. The effective atomic number (Zeff ), dimensionless quantity, can be obtained from σa and σe: Zeff ¼
Zeff NE ¼ N P i fi Ai
Table 2 Nuclear data on the radioactive point sources used in the measurements. Activity (kBq)
Half life (y)
Energy (keV) –Decay probability (%)
22
456
2.60
54 57
378 413
0.86 0.74
60
424
5.27
460
10.51
511.003 (179.80%) 1274.530 (99.94%) 834.848 (99.98%) 122.061 (85.60%) 136.474 (10.68%) 1173.237 (99.97%) 1332.501 (99.99%) 80.997 (34.06%) 160.613 (0.65%) 276.398 (7.16%) 302.853 (8.33%) 356.017 (62.05%) 383.851 (8.94%) 661.657 (85.10%) 778.9(12.9%) 867.3(4.23%) 964.1(14.51%) 1085.8(10.11%) 1112.1(13.67) 1299.1(1.63%) 1408(20.87%) 59.54 (35.9%)
Na Mn Co Co
133
Ba
137
Cs Eu
152
241
Am
473 370000
460
30.07 13.517
432.2
(5)
Besides, the effective electron density (NE ; electron/g) is closely related to the effective atomic number (Zeff ) and is defined as the number of electrons per unit mass of the interacting materials. For the polymer concretes, NE can be calculated by using the following equation [30]:
Fig. 1. Transmission geometry employing HPGe detector and gamma point sources.
Source
σa σe
(6)
The half-value layer (HVL; cm) defines the thickness at which the transmitted intensity is 50% of the original intensity. Tenth-value layer (TVL; cm) expresses the average amount of material thickness that re duces the radiation to the tenth of the incident intensity (90% reduc tion). HVL and TVL values of the polymer concrete are calculated using the following formula [31]:
μ
(7)
TVL ¼ ln10=
(8)
HVL ¼ ln2=
μ
Furthermore, the mean free path (MFP, cm) denotes the average distance between two successive gamma photon interactions. The (MFP, cm) can be evaluated by using the following equation [32]: MFP ¼ 1=
μ
(9)
The radiation protection efficiency (RPE) of any material is deter mined as follows [33]: � � I RPE ¼ 1 :100 (10) I0
mixture. The μm value of the polymer concrete can be computed for the investigated energy region using XCOM software based on the mixture rule. Furthermore, the μ/ρ quantity is the main tool to obtain many related attenuation quantities such as total atomic and electronic crosssections, tenth and half-value layers [28]. The total atomic cross-section (σt,a) is derived using the following expression: � � μ=ρ σ t;a ¼ P wi (3) N A i Ai
2.3. FLUKA simulation code FLUKA is a Monte Carlo simulation code employed to obtain the radiation shielding parameters for unsaturated polyester based com posites. In addition to the experimental and XCOM database, FLUKA has been used to estimate the attenuation coefficients of reinforced polyester-based composites due to its suitability for selecting better shielding material. FLUKA has the ability to simulate the transportation of more than sixty particles namely photons, neutrons, heavy-ions and electrons in different target materials [34,35]. The provision of designing the simple as well as complex geometries is possible through FLUKA Monte Carlo simulations. A database analysis interface, known as Flair, was used for editing files, code running, obtaining and visuali zation of the desired outputs [36]. In FLUKA there is an input file known as BEAM with the help of which it is convenient to choose the type of transporting particle, its
where NA is the Avogadro number, Ai is the atomic weight of the ith element in the polymer concretes. It is expressed in cm2/atom. The total electronic cross-section (σt,el, cm2/electron) can be obtained as follows [29]: 3
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direction of propagation and starting point as well as the energy of the particle. Input data file for shielding composites were arranged in a typical order as per simulation requirements. A rectangular geometry was designed in the input simulation file, by choosing z-direction as the direction of propagation of gamma photons. A beam with 1x105 parti cles was directed on the polyester-based reinforced composites and attenuated in rectangular parallelepiped (RPP) composites. An RPP is defined by the minimum and maximum limits (in cm) of coordinates which bound the chosen parallelepiped in the following order: Xmin, Xmax, Ymin, Ymax, Zmin, Zmax. In the present simulation work, the coor dinate boundaries were set at Xmin (Ymin) and Xmax (Ymax) 5 cm and þ5 cm respectively as sketched in Fig. 2. This results in 10 cm height and breadth of the target materials with different lengths (thicknesses). The photon transmission results have been obtained using USRBDX score card, after the code was run for 5 cycles, with different sample thick nesses. This scorecard is appropriate to define a detector for estimation of fluence on the boundary between selected regions. The polyesterbased composites have been simulated by a MATERIAL card, in addi tion to desired COMPOUND cards to define a typical composition [24]. The MATERIAL card used to define the desired composition includes the composition name, sequence number, and its density, etc. Other tech nical details have been mentioned in our previous work [18].
well as the input file used in the FLUKA simulation are suitable to report the μ/ρ for the polymer concrete samples with different BiClO concen tration. Moreover, Fig. 4 compares the mass attenuation coefficient of the present samples to other concretes reported by Bashter [37], Agar et al. [38,39]. Obviously, from this figure, the BiClO(20%) sample, which is the end-point of compositions studied, is more effective than all the compared concrete samples. The synthesized sample represents su perior shielding efficiency compared with the five types of concretes displayed in Fig. 4. Obviously as one can notice in Fig. 3, μ/ρ decreases exponentially with the energy (except at 122.1 keV), which agrees with Lambert-Beer law and this trend in the μ/ρ means that the attenuation ability of the samples under evaluation is relatively high at low energy, and the samples can shield more photons, while this ability to shield photons reduces as the energy increases. According to Fig. 3, we can notice that the μ/ρ reaches its highest at the end-point energy of 59.5 keV (0.3780, 0.5480, 0.7070 and 0.8530 cm2/g for concrete polymer with 5, 10, 15 and 20% respectively). The photoelectric phenomenon clearly affects the μ/ρ values at low energy and this explains the quick decrease observed in the μ/ρ values at low energy. As can be seen from Table 3, all the polymer concretes have almost the same μ/ρ values for 1112.1 keV < E < 1408 keV and this is attributed to Compton scattering. Besides, an increase in μ/ρ is observed with increase in the concentration of BiClO. This increase occurs since the bismuth is a heavy element (Z ¼ 83) and it is known that the heavy elements are preferable for shielding application. The linear attenuation coefficients (μ) at the investigated energies shown in Fig. 5, also show a decreasing trend (except at 122.1 keV) and the highest μ values for all the samples with different BiClO content are found at the end-point of 59.5 keV, to be 0.5000, 0.7580, 0.9949 and 1.2190 cm 1 for 5, 10, 15 and 20 wt% of BiClO, respectively. Also, the addition of BiClO content leads to an increase in the μ values at all the energies and this is in agreement with the previous curve. The radiation protection efficiency (RPE) is another way to estimate the number of photons that can penetrate the attenuator material and thus, gives an indication about the number of photons that can be blocked or attenuated from the polymer concrete sample. The intensities of original and transmitting photons guided us to calculate the RPE for the polymer concretes with 5, 10, 15 and 20 wt% BiClO content at the investigated energies (between 59.5 keV and 1408 keV) and the results have been plotted in Fig. 6. The maximum RPE for the prepared polymer concretes occurs at the lowest energy 59.5 keV and is equal to 72.04% for the sample with 20 wt% of BiClO content, which is the end-point of compositions studied. It can be observed from the RPE curve that the polymer concrete samples have high attenuation capability at low en ergy. For example, at the end-point of 59.5 keV, BiClO(20%) the sample can shield 72.04% of the incoming photons and thus only 27.96% of the photons can penetrate through this sample. From Fig. 6, we can also notice that the RPE decreases with the increase in energy and this is expected according to the results shown by the previous parameter. Moreover, it is found that the RPE of BiClO(20%) sample, which is the end-point of compositions studied, is higher than the RPE of the remaining concretes. This higher RPE for this concrete polymer sample is due to the higher content of Bi. This signifies that BiClO(20%) pro vides better attenuation of gamma photons. Additionally, the RPE re sults show that above 1085.8 keV energy, all the prepared samples have almost the same RPE values. For example, the RPE for BiClO(5%) and BiClO(20%) samples at 1212.9 keV are 8.79 and 8.88% respectively. From the RPE results, we can conclude that the BiClO(20%), which is the end-point of compositions studied, has superior attenuating perfor mance than the other polymer concrete samples, and all these materials are more efficacious for attenuating the low energy photons. The exact attenuator thickness needed for diminishing the photons intensity to exactly one-half of the original values can be represented by the half-value layer (HVL). This thickness depends inversely on the density of the sample. The data regarding the HVL for the prepared
3. Results and discussion The μ/ρ values of the four polymer concrete samples with different Bi concentration (5%, 10%, 15%, and 20%) were measured experimentally as illustrated in section 2. Moreover, to validate the experimental setup used in the present investigation, the μ/ρ of these polymer concretes were simulated using Monte Carlo code based FLUKA and was evaluated theoretically by XCOM database. The experimental, FLUKA and XCOM based mass attenuation coefficient values of the prepared polymer concretes at twenty-two energies (59.5 keV–1408 keV) are collected and summarized in Table 3 and plotted in Fig. 3. From the data presented in the table, we can deduce that the agreement between measured, simu lated and XCOM based μ/ρ results is extremely acceptable. For instance, for BiClO (5%) at 59.5 keV (very low energy) the measured value is 0.3787 cm2/g, which is very close to the FLUKA value (0.3762 cm2/g) and XCOM value (0.3780 cm2/g). For the same sample at 1112.1 keV (as an example), the measured value is reported as 0.0610 cm2/g, while the FLUKA and XCOM values are 0.0631 and 0.0632 cm2/g respectively. For all the other samples and the investigated energy values, the measured μ/ρ values agree well with the FLUKA and XCOM. From this, we can surely assume that the present setup used for the μ/ρ measurements as
Fig. 2. Sketch of simulated geometry chosen through Flair. 4
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Table 3 Comparison of experimental, XCOM and FLUKA based mass attenuation coefficients of the investigated polyester concretes. Energy (keV)
59.5 80.9 122.1 136.4 276.3 302.8 356.0 383.8 511.0 661.6 778.9 834.8 867.3 964.1 1085.8 1112.1 1173.2 1212.9 1274.5 1299.1 1332.5 1408.0
Mass attenuation coefficients (cm2/g) BiClO (5%)
BiClO (10%)
BiClO (15%)
BiClO (20%)
Exp.
XCOM
FLUKA
Exp.
XCOM
FLUKA
Exp.
XCOM
FLUKA
Exp.
XCOM
FLUKA
0.3787 � 0.0078 0.2539 � 0.0052 0.2798 � 0.0062 0.2467 � 0.0131 0.1258 � 0.0046 0.1189 � 0.0029 0.1067 � 0.0022 0.1020 � 0.0033 0.0944 � 0.0019 0.0804 � 0.0017 0.0749 � 0.0020 0.0711 � 0.0018 0.0729 � 0.0028 0.0656 � 0.0015 0.0643 � 0.0017 0.0610 � 0.0013 0.0604 � 0.0013 0.0591 � 0.0030 0.0616 � 0.0013 0.0574 � 0.0022 0.0569 � 0.0012 0.0530 � 0.0011
0.3780 0.2530 0.2720 0.2360 0.1290 0.1220 0.1120 0.1070 0.0929 0.0819 0.0756 0.0730 0.0717 0.0680 0.0640 0.0632 0.0615 0.0604 0.0589 0.0583 0.0575 0.0559
0.3762 0.2516 0.2718 0.2360 0.1286 0.1172 0.1108 0.1072 0.0925 0.0819 0.0756 0.0724 0.0715 0.0673 0.0643 0.0631 0.0617 0.0605 0.0588 0.0581 0.0576 0.0558
0.5710 � 0.0118 0.3449 � 0.0070 0.3690 � 0.0080 0.3127 � 0.0155 0.1371 � 0.0051 0.1274 � 0.0031 0.1182 � 0.0025 0.1152 � 0.0040 0.0965 � 0.0020 0.0798 � 0.0016 0.0780 � 0.0021 0.0751 � 0.0019 0.0707 � 0.0026 0.0662 � 0.0015 0.0642 � 0.0016 0.0611 � 0.0013 0.0644 � 0.0014 0.0598 � 0.0028 0.0615 � 0.0013 0.0600 � 0.0022 0.0557 � 0.0012 0.0545 � 0.0011
0.5480 0.3280 0.3810 0.3170 0.1410 0.1320 0.1180 0.1120 0.0951 0.0829 0.0761 0.0734 0.0720 0.0682 0.0641 0.0633 0.0615 0.0604 0.0588 0.0583 0.0575 0.0558
0.5480 0.3249 0.3809 0.3180 0.1415 0.1313 0.1174 0.1118 0.0949 0.0827 0.0759 0.0734 0.0720 0.0679 0.0642 0.0632 0.0612 0.0602 0.0589 0.0582 0.0574 0.0558
0.6784 � 0.0143 0.4148 � 0.0086 0.4709 � 0.0108 0.4115 � 0.0224 0.1458 � 0.0048 0.1437 � 0.0036 0.1261 � 0.0026 0.1167 � 0.0037 0.0998 � 0.0021 0.0851 � 0.0017 0.0766 � 0.0020 0.0747 � 0.0018 0.0743 � 0.0029 0.0663 � 0.0015 0.0623 � 0.0016 0.0635 � 0.0014 0.0605 � 0.0013 0.0593 � 0.0028 0.0576 � 0.0012 0.0567 � 0.0020 0.0598 � 0.0012 0.0561 � 0.0012
0.7070 0.3980 0.4820 0.3940 0.1530 0.1410 0.1240 0.1170 0.0972 0.0838 0.0767 0.0738 0.0723 0.0683 0.0641 0.0633 0.0615 0.0604 0.0588 0.0582 0.0574 0.0558
0.6983 0.3954 0.4681 0.3923 0.1520 0.1406 0.1300 0.1166 0.0973 0.0834 0.0764 0.0739 0.0722 0.0684 0.0639 0.0631 0.0614 0.0601 0.0586 0.0581 0.0575 0.0557
0.8273 � 0.0181 0.4819 � 0.0104 0.5946 � 0.0154 0.4423 � 0.0250 0.1656 � 0.0055 0.1440 � 0.0035 0.1253 � 0.0026 0.1175 � 0.0043 0.0946 � 0.0019 0.0848 � 0.0017 0.0809 � 0.0021 0.0725 � 0.0018 0.0746 � 0.0029 0.0688 � 0.0015 0.0633 � 0.0016 0.0616 � 0.0013 0.0638 � 0.0013 0.0604 � 0.0030 0.0572 � 0.0012 0.0559 � 0.0022 0.0562 � 0.0012 0.0548 � 0.0011
0.8530 0.4630 0.5760 0.4640 0.1640 0.1490 0.1290 0.1210 0.0991 0.0847 0.0771 0.0742 0.0726 0.0685 0.0642 0.0633 0.0615 0.0604 0.0588 0.0582 0.0574 0.0557
0.8455 0.4561 0.5762 0.4631 0.1593 0.1484 0.1281 0.1218 0.0989 0.0844 0.0768 0.0739 0.0725 0.0682 0.0638 0.0632 0.0615 0.0603 0.0587 0.0582 0.0571 0.0555
Fig. 3. The experimental, FLUKA and XCOM based mass attenuation coefficients for the BiClO filler composites.
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Fig. 4. The mass attenuation coefficients of the prepared polyester concretes in comparison to some standard and different concretes. Fig. 6. Comparison of radiation protection efficiency (RPE) for the prepared concretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
Fig. 5. Comparison of linear attenuation coefficients for the prepared concretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
polymer concretes with different BiClO content are presented graphi cally in Fig. 7. Apparently, as the energy changes from 59.5 keV to 1408 keV, the HVL values show an increase. This result implies that increasing the energy of the photons makes the photons capable of sharply penetrating through the polymer concretes under evaluation. The results also showed that the HVL for the highest density polymer concrete sample namely BiClO(20%) is lower than other samples (BiClO (5%), BiClO(10%) and BiClO(15%)), while BiClO(5%) which possesses the lowest weight fraction of Bi and thus the lowest density (ρ ¼ 1.322 g/ cm3) has the highest HVL values. For instance, at 136.4 keV, the thick ness of BiClO(5%) is 2.220 cm to decrease the photon intensity to 50%, while BiClO(20%) needs to be 1.046 cm thick for the same reduction. Moreover, the HVL for the same two samples at 1112 keV is 8.294 cm and 7.658 cm respectively. These findings show how the shielding per formance of the prepared polymer concretes with different BiClO con tent is highly inversely proportional to the density. The same HVL dependence of the density was found for other materials such as alloys [14,15] and glasses [40]. Therefore, we can state that increasing the Bi content leads to an increase in the density of the prepared polymer concrete samples and this leads to improvisation of the
Fig. 7. Comparison of half value layer (HVL) for the prepared concretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
photons-attenuating ability of the investigated polymer concretes. Figs. 8 and 9 present other two valuable parameters usually used to estimate the photons attenuation performance of different materials. These two parameters are the tenth value layer (TVL) and mean free path (MFP). It is important to state that lower TVL and MFP values imply more interactions between photons and the prepared polymer concretes; hence the attenuating efficiency is better. According to the analysis of both parameters for the polymer concretes, the TVL and MFP were increased quickly as a function of the energy. In other words, the results of these two parameters were very similar to those found for the HVL presented in the previous figure. It should be noted that the TVL and MFP values were decreased with increase in the density of the polymer concretes. For example, as the density increases from 1.322 to 1.429 g/cm3, the TVL decreases from 7.062 to 3.644 cm (this is at 136.4 keV). Also, at 383.8 keV and for the same two samples, the MFP decreases from 17.083 to 13.715 cm. Similar 6
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Fig. 8. Comparison of tenth value layer (TVL) for the prepared concretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
Fig. 10. Comparison of effective atomic number (Zeff) for the prepared con cretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
Fig. 9. Comparison of mean free path (MFP) for the prepared concretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
Fig. 11. Comparison of effective electron density (NE) for the prepared con cretes with thickness of 1 cm in energy region between 59.5 keV and 1408 keV.
dependences of the TVL as well as MFP on the density are also reported for glasses [41] and concretes [39]. Figs. 10 and 11 show the calculated Zeff and NE values for four polymer concrete samples with different BiClO concentration (5, 10, 15 and 20%) as a function of the energy. It is obvious that Zeff and NE values decreased with the increase in the energy from 59.5 keV to 1408 keV (except at 122.1 keV), but this trend was most pronounced at low en ergies where the photoelectric effect dominated. The Zeff values for BiClO(5%), BiClO(10%), BiClO(15%) and BiClO(20%) are respectively in the range 9.0205–4.6052, 12.8729-4.7808, 16.3812-4.9585, 19.5261-5.1343. Considering the changes in the weight fractions of the constituent elements for the prepared polymer concretes, the Zeff for BiClO(20%), which is the end-point of compositions studied, is higher than the other samples under evaluation, whereas BiClO(5%) possesses the lowest Zeff. The weight fraction of oxygen (Z ¼ 8), carbon (Z ¼ 6), bismuth (Z ¼ 83) in BiClO(5%) are 34.2837, 56.9947 and 3.6309% respectively, while for BiClO(20%) they are 30.9203%, 50.1826%, and
12.7878%; i.e., as the Bi content increases in the BiClO(20%) sample, the amount of oxygen and carbon decrease and this leads to an increase in the Zeff. Taking into account the Zeff results presented in Fig. 10, the BiClO(20%) can shield photons better than other concrete polymers which were used in this investigation. It can be noticed from Fig. 11 that the NE follows the order: BiClO(20%)> BiClO(15%)> BiClO(10%)> BiClO(5%). This means that an addition of BiClO increases the NE values and this is due to the dependence of this parameter on the Zeff. Similar results were found in the literature for other materials such as glasses [42] where the NE has similar behavior with Zeff. 4. Conclusions This paper focused on estimating the appropriate experimental, XCOM and FLUKA results in terms of gamma attenuation features for concretes including unsaturated polyester at various energies between 59.5 keV and 1408 keV. The following conclusions can be drawn from 7
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the study:
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� To ensure higher accuracy in shielding effectiveness, the experi mental values have been supported with those of XCOM database and FLUKA Monte Carlo code results. � FLUKA has been employed as an alternative in estimating the radi ation shielding parameters of polyester-based concretes for the first time. � It has been observed that BiClO (20%) concrete, which is the endpoint of compositions studied, containing a high amount of Bi consistently possesses the best photon-shielding performance in comparison to other samples. � The encouraging finding emphasizes the relevance of using com posite with the insertion of BiClO content to attenuate photon more. Accordingly, such concretes maybe useful for low-energy ionizing radiation as promising shielding absorber. In addition, the unsatu rated polyester, being a quite light material, can be conveniently put into a number of uses, namely storage and transportation, when compared to other materials. � The usage of eco-friendly BiClO based concretes may be utilized to protect people and equipment operating in hospitals and medical centers, shielding of reactors, storage of radioactive waste products, rooms with radiation emitting devices from ionizing radiation. Moreover, it is anticipated that the use of Pb-doped materials with too much toxic effect, high cost and heaviness for transportation and storage will be reduced. � The present results are expected to be useful in dosimetry, radiation shielding, and other radiation-related fields. Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi. org/10.1016/j.matchemphys.2019.122330. References [1] W.R. Leo, Techniques for Nuclear and Particle Physics Experiments, SpringerVerlag Berlin Heidelberg, 1994, https://doi.org/10.1007/978-3-642-57920-2. [2] O. Gencel, W. Brostow, C. Ozel, M. Filiz, An investigation on the concrete properties containing colemanite, Int. J. Phys. Sci. 5 (3) (2010) 216–225. [3] O. Gencel, The application of artificial neural networks technique to estimate mass attenuation coefficient of shielding barrier, Int. J. Phys. Sci. 4 (12) (2009) 743–751. [4] O. Gencel, A. Bozkurt, E. Kam, T. Korkut, Determination and calculation of gamma and neutron shielding characteristics of concretes containing different hematite proportions, Ann. Nucl. Energy 38 (12) (2011) 2719–2723, https://doi.org/ 10.1016/j.anucene.2011.08.010. [5] N.R. Abd Elwahab, N. Helal, T. Mohamed, F. Shahin, F.M. Ali, New shielding composite paste for mixed fields of fast neutrons and gamma rays, Mater. Chem. Phys. 233 (2019) 249–253, https://doi.org/10.1016/j.matchemphys.2019.05.059. [6] R. Bagheri, A.K. Moghaddam, A. Yousefi, Gamma-ray shielding study of light to heavyweight concretes using MCNP-4C code, Nucl. Sci. Tech. 28 (2) (2017) 15, https://doi.org/10.1007/s41365-016-0167-6. € Kılıço� [7] O. glu, H.O. Tekin, V.P. Singh, Determination of mass attenuation coefficients of different types of concretes using Monte Carlo method, Eur. J. Sci. Technol. (2019) 591–598, https://doi.org/10.31590/ejosat.535203. [8] S.S. Obaid, D.K. Gaikwad, P.P. Pawar, Determination of gamma ray shielding parameters of rocks and concrete, Radiat. Phys. Chem. 144 (2018) 356–360, https://doi.org/10.1016/j.radphyschem.2017.09.022. [9] M. Çelikbilek Ersundu, A.E. Ersundu, M.I. Sayyed, G. Lakshminarayana, S. Aydin, Evaluation of physical, structural properties and shielding parameters for K2O–WO3–TeO2glasses for gamma ray shielding applications, J. Alloy. Comp. 714 (2017) 278–286, https://doi.org/10.1016/j.jallcom.2017.04.223. [10] M.I. Sayyed, H.O. Tekin, O. Kılıcoglu, O. Agar, M.H.M. Zaid, Shielding features of concrete types containing sepiolite mineral: comprehensive study on experimental, XCOM and MCNPX results, Results Phys 11 (2018), https://doi.org/10.1016/j. rinp.2018.08.029.
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