Gamma-ray Attenuation Coefficients Research Articles

Determination of gamma ray attenuation coefficients of Al-4% Cu/B4C metal matrix composites at 662, 1173 and 1332 keV

Gamma ray attenuation coefficients of metal matrix composites have been investigated. For this purpose, the linear attenuation coefficients of composites containing boron carbide (B4C) at different rates have been measured using a gamma spectrometer that contains a NaI(Tl) detector and MCA at 662, 1173 and 1332 keV, which are obtained from 137Cs and 60Co sources. The measured results were compared with the calculation obtained using computer code of XCOM for 1 keV–1 GeV gamma energies.

Calculation of gamma-ray mass attenuation coefficients of some Egyptian soil samples using Monte Carlo methods

Monte Carlo simulations, FLUKA and Geant4, were performed to study mass attenuation for various types of soil at 59.5, 356.5, 661.6, 1173.2 and 1332.5 keV photon energies. Appreciable variations are noted for all parameters by changing the photon energy and the chemical composition of the sample. The simulations parameters were compared with experimental data and the XCOM program. The simulations show that the calculated mass attenuation coefficient values were closer to experimental values better than those obtained theoretically using the XCOM database for the same soil samples. The results indicate that Geant4 and FLUKA can be applied to estimate mass attenuation for various biological materials at different energies. The Monte Carlo method may be employed to make additional calculations on the photon attenuation characteristics of different soil samples collected from other places.

Gamma ray attenuation in a developed borate glassy system

Measurements and calculations of gamma ray attenuation coefficients in glass barriers of xBaO–5ZnO–5MgO–14Na2O–-1Li2O–(75−x)B2O3, previously prepared by the melt-quenching technique [1], were performed for γ-ray of energies 121.8, 244.7, 344.14, 661.66, 778.7, 974, 1086.7, 1173.24, 1332.5, and 1407.9keV; which emitted from 152Eu, 137Cs, and 60Co radioactive gamma ray sources. The transmitted γ-rays were detected by 3″×3″ and 5″×5″ NaI (Tl) scintillation γ-ray spectrometers, and a highly calibrated survey meter. The mass attenuation coefficients of γ-rays (σ(E)) were deduced from the attenuation curves, while the WinXCom computer program (version 3.1) was used to calculate the mass attenuation coefficients of γ-rays for such energies at different barium concentrations of a glassy system. A good agreement between both experimental and theoretical results was achieved as well as results obtained by other workers in similar field.

Radiation Shielding Characteristics of Concretes Incorporates Different Particle Sizes of Various Waste Materials

In this study, the dependence of gamma-ray absorption coefficient on the particulate matter sizes of steel slag, iron fillings and steel balls incorporated concrete were examined. The contents of these fillers in concrete mix was kept constant to 35 wt. %. Only the filler particle size was varied during the tests. The particle size ranged from 0.2mm to 1mm for steel slags and the iron fillings and from 2.5mm to 10mm for the steel balls.The concrete samples were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation source was Cs137 radioactive element with photon energy of o.662 MeV. The results showed that gamma-ray attenuation coefficient was inversely proportional to the filler particulate matter size. Likewise the mean free paths for the tested samples were obtained. Maximum linear attenuation coefficient of 1.102±0.263cm-1 was attained for the iron filling.The iron balls and the steel slags showed much inferior values. The concrete incorporates iron filings afforded the best shielding effect. The density, microstructure, homogeneity and particulate distribution of the concrete samples were examined and evaluated using different metallographic, microscopic and measurement facilities.

A fast neutron and dual-energy gamma-ray absorption method (NEUDEG) for investigating materials using a 252Cf source

DEXA (dual-energy X-ray absorption) is widely used in airport scanners, industrial scanners and bone densitometers. DEXA determines the properties of materials by measuring the absorption differences of X-rays from a bremsstrahlung tube source with and without filtering. Filtering creates a beam with a higher mean energy, which causes lower material absorption. The absorption difference between measurements (those with a filter subtracted from those without a filter) is a positive number that increases with the effective atomic number of the material. In this paper, the concept of using a filter to create a dual beam and an absorption difference in materials is applied to radiation from a 252Cf source, called NEUDEG (neutron and dual-energy gamma absorption). NEUDEG includes absorptions for fast neutrons as well as the dual photon beams and thus an incentive for developing the method is that, unlike DEXA, it is inherently sensitive to the hydrogen content of materials. In this paper, a model for the absorption difference and absorption sum in NEUDEG is presented using the combined gamma ray and fast neutron mass attenuation coefficients. Absorption differences can be either positive or negative in NEUDEG, increasing with increases in the effective atomic number and decreasing with increases in the hydrogen content. Sample sets of absorption difference curves are calculated for materials with typical gamma-ray and fast neutron mass attenuation coefficients. The model, which uses tabulated mass attenuated coefficients, agrees with experimental data for porcelain tiles and polyethylene sheets. The effects of “beam hardening” are also investigated.

Investigation of lead borate glasses doped with aluminium oxide as gamma ray shielding materials

Gamma-ray attenuation coefficients of xPbO⋅(0.90−x)B2O3⋅0.10Al2O3 (x=0.25, 0.30, 0.35, 0.40 and 0.45) glass system have been calculated with WinXCOM computer program developed by National Institute of Standards and Technology. Results have been further used to calculate half value layer and mean free path values. Gamma-ray shielding parameters of glass samples have been compared with standard nuclear radiation shielding concretes. The prepared glass samples have higher values of mass attenuation coefficients and lower values of half value layer as compared to concretes for most of gamma ray energy range. The density, molar volume, X-ray diffraction, UV–visible studies, ultrasonic and DSC investigations have been used to study the structural properties of the glass samples. It has been inferred that increase in the composition of PbO leads to the formation of non bridging oxygens which leads to decrease in the rigidity of the glass samples.

Monte Carlo calculations for gamma-ray mass attenuation coefficients of some soil samples

We developed a simple Monte Carlo code to determine the mass attenuation coefficients of some soil samples at nine different gamma-ray energies (59.5, 80.9, 122.1, 159.0, 356.5, 511.0, 661.6, 1173.2 and 1332.5keV). Results of the Monte Carlo calculations have been compared with tabulations based upon the results of photon cross section database (XCOM) and with experimental results by other researchers for the same samples. The calculated mass attenuation coefficients were found to be very close to the theoretical values and the experimental results.

Investigation of Heat Effect on the Shielding Properties of Some Local Concretes

Investigation of Heat Effect on the Shielding Properties of Some Local Concretes The effect of heat on gamma ray and fast neutron shielding properties of two types of the local concretes (basalt concrete; ρ=2.2 g/cm3 and magnetite concrete; ρ=3.9 g/cm3) with two different water to cement ratios for both were investigated. The samples were exposed to temperatures between 20 to 300°C and 800°C. Small losses in attenuation coefficients for gamma rays and fast neutrons were observed for the studied types of concretes. Investigations have been performed using a narrow beam of Cs-137 source and a collimated beam from ET-RR-1 reactor. A gamma spectrometer with NaI (Tl) detector and a neutron-gamma spectrometer with stilbene scintillator were used during measurements.

An investigation on determination of attenuation coefficients for gamma-rays by Monte Carlo method

The radiation attenuation coefficients μ/ρ (cm2 g−1) for concrete and cement samples that used for experimental studies by other researchers were determined by Monte Carlo calculations at 59.5, 80, 356, 661.6, 1173.2 and 1332.5 keV photon energies. The simulated results of attenuation coefficients were compared with the reported experimental data for the same samples and a good agreement has been observed. The intent of this research was to develop a Monte Carlo program useful for various absorbers and energies. The variation of the attenuation coefficient with photon energy has also been investigated for these samples.

A method to determine the gamma-ray linear attenuation coefficient

In this work, gamma-ray linear attenuation coefficients of the materials such as Pb, Fe, Cu and Al were determined by means of traditional energy method and the developed timing detection technique. 1.33 MeV-energy radiation emitted from 60Co radioisotope was used in the experiments. The gamma-ray linear attenuation coefficient values of the materials were calculated by using Xcom code, and the experimental results were compared with the theoretical ones.

Dependence of gamma-ray absorption coefficient on the size of lead particle

In this study, dependence of gamma-ray absorption coefficient on the size of Pb particle size ranging from 200µm up to 2.5mm, using different weights of each particle size. The results show that gamma-ray attenuation coefficient is inversely proportional with the size of Pb particle size due to the reduction of the spaces between the lead particles.

Dependence of gamma-ray absorption coefficient on the size of lead particle

In this study, dependence of gamma-ray absorption coefficient on the size of Pb particle size ranging from 200µm up to 2.5mm, using different weights of each particle size. The results show that gamma-ray attenuation coefficient is inversely proportional with the size of Pb particle size due to the reduction of the spaces between the lead particles.

A performance study of radio-opaque personal protective fabrics for the reduction of transmittance of gamma-rays and neutrons

Commercial radio-opaque combat (CRC) fabrics, for incorporation into personal protective equipment used by first responders and armed forces, are marketed as having the ability to provide a level of protection against specific types of radiation. For a CRC material, a standard combat uniform and a multi-layered chemical, biological, radiological, nuclear (CBRN) protective material, the present work examines chemical composition and radiation protection against gamma-rays and neutron fluxes. Significant reduction in gamma-ray transmittance occurs only for the CRC fabric (46–514 keV) with gamma-ray attenuation coefficients of 3.10 to <0.10 cm2 g−1. Reduction in neutron transmittance, for all three fabrics, could not be assessed with certainty as the measured transmittance was obscured by large statistical uncertainties.

Gamma Ray Attenuation Coefficient of Microalloyed Stainless Steel

Gamma ray attenuation coefficients of microalloyed steel have been investigated. For this purposes the linear attenuation coefficients of steel have been measured at the photon energy of 0.662, 1.173 and 1.332 MeV and the results were compared with the calculation at the photon energy of 1–105 MeV obtained using XCOM.

Determination of Linear Attenuation Coefficients of Materials by Using Timing Method

In this work, gamma-ray linear attenuation coefficients of aluminum (Al) and lead (Pb) materials were determined by using timing method. The used setup is different from the conventional ones. The goal of the presented setup is the fact that it is used the timing technique. The detection system is composed of a 3″ × 3″ NaI(Tl) inorganic scintillation detector and related equipment together with 137Cs and 60Co radioactive sources. Obtained results are in good agreement with each other.

Gamma-ray attenuation coefficients of some building materials available in Egypt

Mass attenuation coefficients of various types of building materials were measured using a high-resolution HPGe spectrometer detector. Samples were irradiated by gamma-rays emitted from point sources of 241Am, 133Ba, 60Co and 137Cs. The results are in good agreement with the theoretical calculations of XCOM code. The effectiveness of building materials in shielding were determined over the range 50–3000 keV. Finally, the protection efficiency of walls and roofs from radiation exposure were determined. The effectiveness of all tested building materials was better than the internationally accepted limit, and they are therefore acceptable for use.

Chemical corrosion and gamma-ray attenuation properties of Zr and Ti containing lead silicate glasses

Lead silicate glasses (LSGs) have high gamma-ray attenuation but low chemical durability properties. In this work, LSGs with (55.5–68.5 wt%) PbO content containing ZrO 2 and TiO 2 additions were produced. The chemical corrosion of various produced LSGs in 0.5 N HNO 3 aqueous solution and determination of their gamma-ray attenuation coefficients for 60Co and 137Cs sources were investigated. The weight loss measurements, the SEM micrographs, the EDS analysis of the sample surfaces and the ICP analysis of solution were used to characterize the dissolution process. The effects of PbO content, ZrO 2 and TiO 2 additives on chemical corrosion, and also the effect of PbO on gamma-ray attenuation coefficient, glass transition temperature (Tg), and density of LSG glasses were determined. The results showed that by increasing the lead content of glass the gamma-ray attenuation coefficient, chemical corrosion and density were increased, but the Tg decreased. One of the samples with PbO contents of 65.4 wt% and SiO 2 content of 26.9 wt% showed a very low chemical corrosion behavior and good gamma-ray absorption property.

Gamma-ray shielding and structural properties of PbO–SiO2 glasses

Gamma-ray attenuation coefficients have been determined experimentally using a narrow beam transmission method for the xPbO(1−x)SiO2 (x=0.45–0.70) glass system at 662, 1173 and 1332keV photon energies. These values have also been obtained theoretically using the ‘mixture rule’ and the ‘XCOM’ computer software. The results have been used to calculate half value layer parameters. Gamma-ray shielding properties of PbO–SiO2 glass samples have been compared with standard radiation shielding concretes. The molar volume, FTIR and acoustic investigations have been used to study the structural properties of the prepared glass system.

Gamma ray attenuation coefficient measurement for neutron-absorbent materials

The compounds Na 2B 4O 7, H 3BO 3, CdCl 2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the γ rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H 3BO 3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

Lead- and Bismuth-Borate Fly-Ash Glasses as Gamma-Ray-Shielding Materials

Values of the gamma-ray mass attenuation coefficient for fly-ash glasses in the system: xBi2O3-0.2B2O3-yFly Ash and xPbO-0.2B2O3-yFly Ash (x = 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.40 and y = 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40) have been determined experimentally at 81-, 356-, 511-, 662-, 1173-, and 1332-keV photon energies using a narrow-beam transmission method. These coefficients of glasses are then used to determine their interaction cross sections, the photon mean free path, effective atomic numbers, and the electron densities. Results have indicated that these fly-ash glasses have potential applications in low-energy gamma-ray shielding.