Gamma Ray Exposure Buildup Factors Research Articles

Investigation of gamma radiation shielding properties of various ores

Mass attenuation coefficients (μ/ρ, cm2/g) for some pellet samples produced using barite, magnetite, limonite, hematite and serpentine ores at 81, 276, 302, 356, 383 keV photons emitted from 133Ba and 121, 244, 344, 444, 778 keV photons emitted from 152Eu have been determined by using HPGe detector. Effective atomic numbers (Zeff) and electron densities (Ne) of the ores calculated in the selected energies.. The agreement of measured values of μ/ρ, Zeff and Ne with theoretical calculations is quite satisfactory. Mass attenuation coefficients were found to be highest for barite. The Zeff and Ne values for barite are maximum, for serpentine are minimum. Gamma ray energy absorption (EABF) and exposure buildup factors (EBF) were computed for ore samples using the five-parameter Geometric Progression (G-P) fitting method in the energy range 0.015–15 MeV for penetration depths up to 40 mean free path. Variations of EABF and EBF with incident photon energy and penetration depth were also investigated. It has been observed that among the selected ore samples, barite has lowest values for EABF and EBF in the intermediate energy region. Buildup of photons is more for serpentine. Exposure buildup factors (EBF) of given ores were compared with lead, steel-magnetite concrete (SM), concrete and bismuth borosilicate glass (BBS) with %20 mol Bi2O3. Barite is superior in terms of shielding properties among the other ore samples. The present study may be useful for radiation shielding applications.

Shielding efficiency of lead borate and nickel borate glasses for gamma rays and neutrons

Gamma ray exposure buildup factor (EBF) and neutron shielding efficiency of borate glass systems in composition (100 − x − y) Na2B4O7−xPbO−yNiO (where x and y = 0, 2, 4, 6, 8 and 10 weight percentage) were investigated in the present study. Gamma ray EBF values were computed using Geometric Progression (G-P) method for photon energy 0.015 to 15 MeV up to penetration depths of 40 mfp (mean free path). The macroscopic effective removal cross-sections (Σ R ) for fast neutron (2 to 12 MeV) were calculated. At low- and high-energy region, the EBF values were found minimum whereas maximum in the intermediate-energy regions with a sharp peak below 100 keV for oxide containing glass samples. The investigation was carried out for potential applications of borate glasses for radiation shielding.

Radiation shielding competence of silicate and borate heavy metal oxide glasses: Comparative study

Gamma-ray shielding competence of silicate and borate heavy metal oxide glasses has been investigated using linear attenuation coefficients, effective atomic numbers and exposure buildup factors (EBF). The gamma-ray EBF were computed using the Geometric Progression (G-P) fitting method for photon energies from 0.015 to 15MeV, and for penetration depths up to 40 mean free paths (mfps). The macroscopic effective removal cross-section for fast neutron has been calculated for energy range from 2 to 12MeV. It is found that bismuth silicate glass has superior shielding properties and is suitable for replacement of lead glasses. The present investigation is very useful for gamma-ray and neutron shielding and design for lead-free shielding glass in radiological engineering.

Radiation shielding effectiveness of newly developed superconductors

Gamma ray shielding effectiveness of superconductors with a high mass density has been investigated. We calculated the mass attenuation coefficients, the mean free path (mfp) and the exposure buildup factor (EBF). The gamma ray EBF was computed using the Geometric Progression (G-P) fitting method at energies 0.015–15MeV, and for penetration depths up to 40 mfp. The fast-neutron shielding effectiveness has been characterized by the effective neutron removal cross-section of the superconductors. It is shown that CaPtSi3, CaIrSi3, and Bi2Sr2Ca1Cu2O8.2 are superior shielding materials for gamma rays and Tl0.6Rb0.4Fe1.67Se2 for fast neutrons. The present work should be useful in various applications of superconductors in fusion engineering and design.

A study of the energy absorption and exposure buildup factors of some anti-inflammatory drugs

Human radiation exposure is increasing due to radiation development in science and technology. The development of radioprotective agents is important for protecting patients from the side effects of radiotherapy and for protecting the public from unwanted irradiation. Radioprotective agents are used to reduce the damage caused by radiation in healthy tissues. There are several classes of radioprotective compounds that are under investigation. Analgesics and anti-inflammatory compounds are being considered for treating or preventing the effects of damage due to radiation exposure, or for increasing the chance of survival after exposure to a high dose of radiation. In this study, we investigated the radioprotective effects of some analgesic and anti-inflammatory compounds by evaluating buildup factors. The gamma ray energy absorption (EABF) and exposure buildup factors (EBF) were calculated to select compounds in a 0.015–15MeV energy region up to a penetration depth of 40mfp (mean free path). Variations of EABF and EBF with incident photon energy and penetration depth elements were also investigated. Significant variations in both EABF and EBF values were observed for several compounds at the moderate energy region. At energies below 0.15MeV, EABF and EBF values increased with decreasing equivalent atomic number (Zeq) of the samples. In addition, EABF and EBF were the largest for ibuprofen, aspirin, paracetamol, naproxen and ketoprofen at 0.05 and 0.06MeV, respectively, and the EABF value was 0.1MeV for aceclofenac. From these results, we concluded that the buildup of photons is less for aceclofenac compared to other materials.

Assessment of exposure buildup factors of some oxide dispersion strengthened steels applied in modern nuclear engineering and designs

The gamma-ray exposure buildup factors of oxide dispersive-strengthen (ODS) steel alloys have been computed for photon energy 0.015–15MeV up to 40 mean free path (mfp) penetration depth by geometrical progression (GP) method. An appreciable variation in exposure buildup factors for the investigated ODS steel alloys was observed. The exposure buildup factors of ODS alloys were observed strongly depending upon the photon energy, penetration depths and the chemical compositions. The exposure buildup factors were found to be small in low- and high-photon energy whereas these were very large in intermediate-energy region. Our investigation signifies that the Eurofer 97 ODS steel alloy is the superior gamma-ray and neutron shielding materials. This study should be useful for shielding design and application in future reactor technologies and fusion reactor blankets.

Evaluation of gamma-ray exposure buildup factors and neutron shielding for bismuth borosilicate glasses

Gamma-ray exposure buildup factor (EBF) values and neutron shielding effectiveness of bismuth borosilicate (BBS) glass systems in composition (50−x)SiO2:15B2O3:2Al2O3:10CaO:23Na2O:xBi2O3 (where x=0, 5, 10, 15 and 20mol%) were calculated. The EBF values were computed for photon energy 0.015–15MeV up to penetration depths of 40mfp (mean free path) by the geometrical progression (G-P) method. The EBF values were found dependent upon incident photon energy, penetration and bismuth molar concentration. In low- and high-energy photon regions, the EBF values were minimum whereas maximum in the intermediate-energy region. The fast neutron removal cross sections for energy 2–12MeV were calculated by the partial density method. The BBS glass with 20mol% Bi2O3 is found to be superior gamma-ray and neutron transparent shielding. The EBF values of the BBS glasses were compared with steel–magnetite concrete and lead. The investigation was carried out to explore the advantages of the BBS glasses in different radiation shielding applications.

The gamma-ray and neutron shielding factors of fly-ash brick materials

A comprehensive study of gamma-ray exposure build-up factors (EBFs) of fly-ash brick materials has been carried out for photon energies of 0.015–15 MeV up to a penetration depth of 40 mfp (mean free path) by a geometrical progression (GP) fitting method. The EBF values of the fly-ash brick materials were found to be dependent upon the photon energy, penetration depth and chemical composition, and were found to be higher than the values for mud bricks and common bricks. Above a photon energy of 3 MeV for large penetration depths (>10 mfp), the EBF becomes directly proportional to Zeq. EBFs of fly-ashes were found to be less than or equal to those of concrete for low penetration depths (<10 mfp) for intermediate photon energies up to 1.5 MeV. The EBF values of fly-ash materials were found to be almost independent of Si concentration. The fast neutron removal cross sections of the fly-ash brick materials, mud bricks and common bricks were also calculated to understand their shielding effectiveness. The shielding effectiveness of the fly-ash materials against gamma-ray radiation was lower than that of common and mud bricks.

A Comprehensive Study on Gamma-Ray Exposure Build-Up Factors and Fast Neutron Removal Cross Sections of Fly-Ash Bricks

Geometric progression (GP) method was utilized to investigate gamma-ray exposure build-up factors of fly-ash bricks for energies from 0.015 to 15 MeV up to 40 mfp penetration depth. The EBFs of the fly-ash bricks are dependent upon the photon energy, penetration depths, and the chemical compositions of the elements. Appreciable variations in exposure build-up factor (EBF) are noted for the fly-ash bricks. The EBFs were found to be small in low and high photon energy regions whereas very large in medium energy region. EBF of the bricks is inversely proportional to equivalent atomic number below 10 mfp for entire energy region of interest 0.015 to 15 MeV. The EBFs of fly-ash, brick of mud, and common brick were similar at 1.5 MeV photon energy. The EBF of the fly-ash bricks was found to be higher than that of the brick of mud, and common brick. The fast neutron removal cross sections of the fly-ash bricks, brick of mud, and common bricks were also calculated which were found to be in the same order. It is expected that this study should be very directly useful for shielding effectiveness of fly-ash brick materials and dose estimation.

Gamma-ray exposure build-up factors of some brick materials in the state of Punjab

The gamma-ray exposure build-up factors of raw materials of bricks (soils and fly-ashes) in the state of Punjab were investigated for the photon energy range 0.015 to 15 MeV up to 40 mfp penetration depth by the geometrical progression (GP) method. Appreciable variations in the exposure build-up factor (EBF) are noted for the raw materials. The EBFs of the raw materials of bricks change depending on the photon energy, penetration depth and chemical composition. The build-up factors are low at low and high photon energies, whereas they are very high in the medium-energy region. The peak energy of the EBF for soils is 0.3 MeV and 0.2 MeV for fly ashes. The EBFs of the raw materials of bricks are also compared with those of bricks of red mud and common brick materials. Common bricks were found to have the lowest gamma-ray EBF. This study should be useful for emergency preparedness planning and emergency dose estimation for future planned nuclear power plants in the state of Punjab.

Studies on energy absorption and exposure buildup factors in some solutions of alkali metal chlorides

Buildup of photons has been investigated through the solutions LiCl, NaCl and KCl with different salt contents in the energy region 0.015-15 MeV up to a penetration depth of 40 mean free paths. Two types of buildup factors, the gamma ray energy absorption () and exposure buildup factors () have been calculated simultaneously using the five parameter geometric progression (G-P) fitting formula. The influence of photon energy, penetration depth and chemical composition on the buildup factors has been studied. Also, a comparison has been made between the values of and if any significant variation occurs between them. Moreover, the Monte Carlo simulation study has been made for the purpose of the comparison. Key words: Gamma ray buildup factor, energy absorption, exposure, solution, Monte Carlo method.

Study of Gamma Ray Exposure Buildup Factor for Some Ceramics with Photon Energy, Penetration Depth and Chemical Composition

Gamma ray exposure buildup factor for some ceramics such as boron nitride (BN), magnesium diboride (MgB2), silicon carbide (SiC), titanium carbide (TiC) and ferrite (Fe3O4) has been computed using five parametric geometric progression (G.P.) fitting method in the energy range of 0.015 to 15.0 MeV, up to the penetration of 40 mean free path (mfp). The variation of exposure buildup factors for all the selected ceramics with incident photon energy, penetration depth, and chemical composition has been studied.

Investigation of X- and gamma ray photons buildup in some neutron shielding materials using GP fitting approximation

In the present work, the gamma ray energy absorption (EABF) and exposure (EBF) buildup factors have been calculated by using the five parameter geometric progression (GP) fitting formula for some neutron absorbent materials (H3BO3, Na2B4O7, NaCl) and neutron moderator hydrocarbons (C5H12, C6H14, C7H16, C20H42, C40H82) in the energy region 0.015–15MeV up to a penetration depth of 40mfp (mean free path). From the results, it has been concluded that the buildup of photons is less in NaCl when compared with other materials for the lower penetration depths (<15mfp for EABF, <10mfp for EBF) whereas for photon energies higher than 3MeV less buildup of secondary gamma rays occur in HC based materials than the other ones at higher penetration depths (>15mfp for EABF, >10mfp for EBF). The present results have been compared with MCNP calculations for various energies at 1mfp and a good correspondance has been obtained.

A Comprehensive Study on Energy Absorption and Exposure Buildup Factors for some Soils and Ceramic Materials

Study of gamma ray energy absorption (EABF) and exposure buildup factors (EBF) for some essential soils, ceramic materials in the energy region 0.015-15 MeV up to a penetration depth of 40 mfp (mean free path). To calculate both EABF and EBF, five parameter geometric progressions (G-P) fitting approximation has been used. Variation of EABF and EBF with incident photon energy, penetration depth and effective atomic number (Zeff) has been studied and presented in the form of graphs. This change results from the dominance of different interaction process in different energy regions. Significant variations were also observed between EABF and EBF which may due to different chemical composition of given materials. Keywords: Cascade silt loam (CSL), Energy absorption buildup factor, Exposure buildup factor, Kaolinite (KLN), Mica, Sand.

Energy absorption and exposure buildup factors for some polymers and tissuesubstitute materials: photon energy, penetration depth and chemical compositiondependence

The gamma ray energy absorption and exposure buildup factors have been calculated byusing the five parameter geometric progression (GP) fitting formula for some polymers andtissue substitute materials in the energy region 0.015–15 MeV up to a penetrationdepth of 40 mean free paths. From the results, it is worth noting that significantvariations occur in gamma ray buildup factors for the given polymers and tissuesubstitute materials depending on photon energy, penetration depth and chemicalcomposition of the materials. Also, it was observed that there are significantvariations between energy absorption (EABF) and exposure (EBF) buildup factorswhich may be due to the variations in chemical composition of the materials used.Finally, it is expected that the presented buildup factor data may be helpful in (a)estimating the effective dose to be given to patients in radiation therapy anddiagnostics, hence allowing corrections to be made to the intensity of radiation, as it issomewhat problematic to evaluate the real absorbed dose in critical organs due to theprobability of photon buildup somewhere inside the medium; (b) estimating thehealth hazards arising from the exposure of the human body to radiation, thusit will be helpful in controlling the exposure of the human body to radiation.

Gamma-ray energy absorption and exposure buildup factor studies in some human tissues with endometriosis

Human tissues with endometriosis have been analyzed in terms of energy absorption (EABF) and exposure (EBF) buildup factors using the five-parameter geometric progression (G-P) fitting formula in the energy region 0.015-15 MeV up to a penetration depth of 40 mfp (mean free path). Chemical compositions of the tissue samples were determined using a wavelength dispersive X-ray fluorescence spectrometer (WDXRFS). Possible conclusions were drawn due to significant variations in EABF and EBF for the selected tissues when photon energy, penetration depth and chemical composition changed. Buildup factors so obtained may be of use when the method of choice for treatment of endometriosis is radiotherapy.

A comprehensive study on energy absorption and exposure buildup factors for some essential amino acids, fatty acids and carbohydrates in the energy range 0.015–15 MeV up to 40 mean free path

The gamma ray energy absorption ( EABF ) and exposure buildup factors ( EBF ) have been calculated for some essential amino acids, fatty acids and carbohydrates in the energy region 0.015–15 MeV up to a penetration depth of 40 mfp (mean free path). The five parameter geometric progression (G-P) fitting approximation has been used to calculate both EABF and EBF . Variations of EABF and EBF with incident photon energy, penetration depth and weight fraction of elements have been studied. While the significant variations in EABF and EBF for amino acids and fatty acids have been observed at the intermediate energy region where Compton scattering is the main photon interaction process, the values of EABF and EBF appear to be almost the same for all carbohydrates in the continuous energy region. It has been observed that the fatty acids have the largest EABF and EBF at 0.08 and 0.1 MeV, respectively, whereas the maximum values of EABF and EBF have been observed for aminoacids and carbohydrates at 0.1 MeV. At the fixed energy of 1.5 MeV, the variation of EABF with penetration depth appears to be independent of the variations in chemical composition of the amino acids, fatty acids and carbohydrates. Significant variations were also observed between EABF and EBF which may be due to the variations in chemical composition of the given materials.

Computation of gamma-ray exposure buildup factors up to 10 mfp using generalized feed-forward neural network

This paper presents an approach based on generalized feed-forward neural network (GFFNN) to compute exposure buildup factors ( B D ) for point isotropic sources in infinite homogeneous media at energies varying from 0.03 MeV to 15 MeV and up to depths of 10 mean free paths (mfp). The results obtained by using the proposed model have been compared with the ANSI standard data, the calculations by use of EGS4 Monte Carlo code and Invariant Embedding (IE) Method for water, iron, lead and concrete. The comparisons have shown that the GFFNN model improved B D estimation with respect to the other methods, particularly for lead and concrete.

Description of Multilayered Gamma-Ray Exposure Buildup Factors up to 40 mfp by the Approximating Model

An approximating formula recently proposed by the authors for γ-ray buildup factors of multilayered shields was applied for very thick shields up to 40 mfp. For this purpose, modifications were made to the model and the fitting method to improve the data reproducibility. The previous model was expanded so that it included both the plane-normal and point isotropic geometries.The verification test of the modified model was made for three materials; water, iron and lead. The separately published data of double-layered shields for point isotropic buildup factors calculated by EGS4 from 0.1 MeV to 10 MeV were used as well as newly calculated data at 1 MeV for the plane-normal geometry, and data for the point isotropic geometry of triple-layered shields at 1and 10 MeV.The present formula generally shows a very good reproducibility of the multilayer buildup factors, even in case of very thick shielding problems. The observed error between the approximating description and the EGS4 data is 15% in the intermediate energy range, about 30% in the higher energy range, and 35% at 0.3 MeV. However, the error in the approximation reaches a factor of 4 in the worst case at 0.1 MeV.

Application of the EGS4 Monte Carlo Code to a Study of Multilayer Gamma-Ray Exposure Buildup Factors of up to 40 mfp

Multilayer γ-ray exposure buildup factors of up to 40 mfp were calculated using an electron-photon cascade Monte Carlo code, EGS4, as a point isotropic source. A kind of splitting technique was used in the EGS4 calculations in order to obtain reasonable results at very deep penetration problems, such as 40 mfp.The double-layer γ-ray exposure buildup factors were calculated for combinations of water, iron and lead for 0.1, 0.3, 0.6, 1.0, 3.0, 6.0 and 10MeV γ-rays. The thickness of the first medium was set to 1, 5, 10 or 20 mfp. As typical triple-layered shields, the calculations were performed for 4 different configurations of water, iron and lead.The behavior of multilayer buildup factors for deep penetration problems was studied using the obtained results. Buildup factors after the bounday show the tendency to vary largely depending on the material combination and the source energy of γ-rays.