Indian Journal of Pure & Applied Physics Vol. 56, May 2018, pp. 383-391 Gamma, X-ray and neutron shielding properties of polymer concretes L Seenappaa,d, H C Manjunathaa*, K N Sridharb & Chikka Hanumantharayappac aDepartment of Physics, Government College for Women, Kolar 563 101, India bDepartment of Physics, Government First grade College, Kolar 563 101, India cDepartment of Physics, Vivekananda Degree College, Bangalore 560 055, India dResearch and Development Centre, Bharathiar University, Coimbatore 641 046, India Received 21 June 2017; accepted 3 November 2017 We have studied the X-ray and gamma radiation shielding parameters such as mass attenuation coefficient, linear attenuation coefficient, half value layer, tenth value layer, effective atomic numbers, electron density, exposure buildup factors, relative dose, dose rate and specific gamma ray constant in some polymer based concretes such as sulfur polymer concrete, barium polymer concrete, calcium polymer concrete, flourine polymer concrete, chlorine polymer concrete and germanium polymer concrete. The neutron shielding properties such as coherent neutron scattering length, incoherent neutron scattering lengths, coherent neutron scattering cross section, incoherent neutron scattering cross sections, total neutron scattering cross section and neutron absorption cross sections in the polymer concretes have been studied. The shielding properties among the studied different polymer concretes have been compared. From the detail study, it is clear that barium polymer concrete is good absorber for X-ray, gamma radiation and neutron. The attenuation parameters for neutron are large for chlorine polymer concrete. Hence, we suggest barium polymer concrete and chlorine polymer concrete are the best shielding materials for X-ray, gamma and neutrons. Keywords: X-ray, Gamma, Mass attenuation coefficient, Polymer concrete 1 Introduction Agosteo et al.11 studied the attenuation of Concrete is used for radiation shielding. Junior secondary radiation in concretes. Maslehuddin et al.12 et al.1 measured the mass attenuation coefficients of studied the radiation shielding properties of X-rays in different barite concretes. Malkapur et al.2 concrete with heavyweight aggregates. Kharita et al.13 evaluated the neutron radiation shielding characteristics investigated the effects of addition of boron of a polymer-incorporated self-compacting concrete compounds on the shielding properties of concretes. mixes. Zorla et al.3 studied the radiation shielding Yao et al.14 studied the gamma ray shielding properties of high strength concrete containing efficiency and mechanical performances of lead varying fractions of natural and enriched boron. and bismuth based concretes. El-Khayatt15 studied Cullu and Ertas4 determined the radiation absorption the gamma and neutrons shielding properties of capacity of concretes produced from lead mine lime/silica concretes. Ochbelagh and Azimkhani16 wastes. Juncai et al.5 established a model to studied the gamma-ray shielding properties of predict the strength of radiation-shielding concretes. concrete containing different percentages of lead. Yadollahi et al.6 studied radiation shielding properties Kharita et al.17 prepared radiation shielding concretes of concretes using artificial neural network. Singh using natural local materials. Pavlenko et al.18 studied et al.7 reported the gamma radiation shielding neutrons and gamma shielding properties of iron- properties of lead-flyash concretes. Fusco et al.8 barium concretes. Nemati et al.19 measured the studied the shielding properties of protective thin film attenuation of neutrons in concretes. Pomaro et al.20 coatings on the blended concrete compositions. studied the radiation damage in concrete shielding for Alhajali et al.9 studied different composition of nuclear physics experiments. Weinreich et al.21 concretes for nuclear reactor shielding. El-Sayed measured the accumulated uranium and plutonium et al.10 reported a comparative study of different content in concretes of nuclear reactor shielding. concrete composition as gamma-ray shielding materials. Singh et al.22 measured the gamma radiation interaction parameters in flyash concretes. In our ———————— 23-28 *Corresponding author (E-mail: [email protected]) previous work , we have measured the X-ray and 384 INDIAN J PURE & APPL PHYS, VOL. 56, MAY 2018 gamma interaction parameters in some compounds of (μ) can be evaluated by multiplying density of dosimetric interest. We also reported theoretical compounds to mass attenuation coefficients: studies on the X-ray and gamma interaction 29-32 μ parameters of biological samples . In our previous μ ρ … (1) 33 work , we have reported shielding parameters for ρ c beta and bremsstrahlung radiation in concretes. The total linear attenuation coefficient (μ) is used in In the present work, we have studied the X-ray and the calculation of half value layer (HVL). HVL is the gamma radiation shielding parameters such as mass thickness of an interacting medium that reduces the attenuation coefficient, linear attenuation coefficient, radiation level by a factor of 2 that is to half the initial half value layer , tenth value layer, effective atomic level and is calculated by the following equation: numbers, electron density, exposure buildup factors, ln2 0.693 relative dose, dose rate and specific gamma ray HVL … (2) constant in some polymer based concretes such as μ μ sulfur polymer concrete, barium polymer concrete, calcium polymer concrete, flourine polymer concrete, The total linear attenuation coefficient (μ) is also chlorine polymer concrete and germanium polymer used in the calculation of tenth value layer (TVL). It concrete. It is also studied the neutron shielding is the thickness of interacting medium for attenuating properties such as coherent neutron scattering length, a radiation beam to 10% of its radiation level and is computed by: incoherent neutron scattering lengths, coherent neutron scattering cross section, incoherent neutron ln10 2.303 TVL … (3) scattering cross sections, total neutron scattering cross μ μ section and neutron absorption cross sections in the polymer concretes. The average distance between two successive interactions is called the relaxation length (λ). It is 2 Theory also called the photon mean free path which is determined by the equation: 2.1 Gamma/X-ray interaction parameters In the present work, the mass attenuation coefficients (MAC) and photon interaction cross x exp(μx)dx 0 1 … (4) sections in the energy range from 1 keV to 100 GeV λ 34 μ are generated using WinXCom and its composition exp(μx)dx (Table 1). The total linear attenuation coefficient 0 Table 1 — Elemental composition of selected polymer based concrete Element Sulfur polymer Barium polymer Calcium Flourine polymer Chlorine polymer Germanium polymer concrete concrete polymer concrete concrete concrete concrete Na 0.18 0.18 0.18 0.18 0.18 0.18 Mg 0.15 0.15 0.15 0.15 0.15 0.15 Al 1.62 1.62 1.62 1.62 1.62 1.62 Si 15.71 15.71 15.71 15.71 15.71 15.71 P 0.12 0.12 0.12 0.12 0.12 0.12 S 24.3 - - - - - Ba - 25 - - - - Ca - - 25.33 - - - F - - - 25 - - Cl - - - - 25 - Ge - - - - - 25 K 0.27 0.27 0.27 0.27 0.27 0.27 Ca 0.33 0.33 0.33 0.33 0.33 Ti 0.19 0.12 0.12 0.12 0.12 0.12 Fe 0.55 0.55 0.55 0.55 0.55 0.55 H 18.86 18.65 18.65 18.65 18.65 18.65 C 18.86 18.65 18.65 18.65 18.65 18.65 O 18.86 18.65 18.65 18.65 18.65 18.65 SEENAPPA et al.: GAMMA, X-RAY AND NEUTRON SHIELDING PROPERTIES OF POLYMER CONCRETES 385 The gamma interaction parameters such as linear secondary radiations through the different interaction attenuation coefficients, μ (cm-1), HVL (in cm), TVL process. The quantity of secondary radiations (in cm) and mean free path λ are calculated using produced in the medium and energy deposited/ above Eqs (1-4). The total molecular cross section σm absorbed in the medium is studied by calculating [milli barn] is computed from the following equation buildup factors. In the present work, we have 29-32 using the values of mass attenuation coefficients estimated energy exposure build up factors (Ben) using 35-37 [(µ/ρ)c]: GP fitting method . We have evaluated the G-P fitting parameters (b, c, a, Xk and d) for different stent 1 μ … (5) alloys using following expression which is based on σm (E) (E) ni Ai N ρ c i Lagrange’s interpolation technique: th where ni is the number of atoms of i element in a (Zeff Z ) Z 'Z … (10) given molecule, (µ/ρ)c is the mass attenuation PZ Pz eff (z Z ) coefficient of compound, N is the Avogadro's number zZ and Ai is the atomic weight of element i. The effective (average) atomic cross section for a particular atom in where lower case z is the atomic number of the element of known G-P fitting parameter Pz adjacent to the compound σa [milli barn] is estimated using the equation29-32: the effective atomic number (Zeff) of the given material whose G-P fitting parameter is desired PZ 1 μ eff (E) ni Ai and upper case Z are atomic numbers of other σm N ρ c i … (6) σa (E) elements of known G-P fitting parameter adjacent to ni ni i i Zeff. GP fitting parameters (b, c, a, Xk and d) for element adjacent to Zeff are provided by the standard The effective electronic cross section σe [milli data available in literature38. The computed G-P barn] is computed from mass attenuation coefficient th fitting parameters (b, c ,a, Xk and d) were then used to (µ/ρ)i of i element in the given molecule using compute the EABF in the energy range 0.015 MeV-15 following equation29-32: MeV up to a penetration depth of 40 mean free path 1 f A μ with the help of G-P fitting formula, as given by the σ (E) i i (E) … (7) 35-37 e equations : N i Z ρ i i b 1 X B(E, X ) 1 (K 1) for K≠1 … (11) where fi is the fractional abundance (a mass fraction K 1 th of the i element in the molecule) and Zi is the atomic for K=1 … (12) th B(E, X ) 1 (b 1)X number of the i element in a molecule.