Measurement Of Mass Attenuation Coefficients Research Articles

RADIATION BEHAVIOR IN BIOLOGICAL COMPOUND: EXPLORING MASS ATTENUATION AND EFFECTIVE ATOMIC NUMBERS FOR GAMMA-RAY INTERACTION

This study involved the measurement of mass attenuation coefficients (μ/ρ) for fatty acids across a range of photon energies (from 122 keV to 1330 keV). These measurements were conducted through transmission experiments employing collimated beams generated by 57Co, 133Ba, 22Na 137Cs, 54Mn, and 60Co sources, each producing beams with a diameter of 0.52 cm. The detection of attenuated radiation was achieved using a NaI (Tl) scintillation detector with an energy resolution of 8.2% at 663 keV. The obtained experimental values of (μ/ρ) were subsequently used to calculate the atomic cross-sections (σa), electronic crosssections (σe), effective atomic numbers (Zeff), and electron densities (Neff). Notably, the study revealed that (μ/ρ), σa, and σe exhibited an initial decrease with increasing photon energy, stabilizing at higher energy levels. In contrast, Zeff and Neff remained relatively constant with changing energy levels. In addition, the research acknowledged that deviations in experimental results for radiological parameters may be influenced by the physical and chemical surroundings of the substances under investigation. Encouragingly, the experimental findings were found to be consistent with values from the WinXCom database, affirming their accuracy and reliability. These outcomes contribute to a deeper understanding of the photon interaction characteristics of these biological substances across diverse energy spectra.

Enhancement of optical and radiation shielding properties in calcium–magnesium silicate bioactive glasses through Na2O and P2O5 additives

The present study investigates the influence of Na2O/MgO and P2O5/SiO2 substitutions on the structure and protective properties of bioactive glasses composed of 32CaO–19MgO–0.5P2O5–0.5CaF2–48SiO2 (mole %). The glass samples are prepared using the conventional melt-quenching method. Optical analyses, including refractive index (n), molar refraction (Rm), and cationic polarizability (αm), are calculated and discussed to examine structural modifications. Raman spectroscopy is employed for detailed structural analysis. The effects of compositional changes on the protective parameters are thoroughly investigated by theoretically determining mass attenuation using the newly developed Phy-X/PSD software and XCOM programs, which are then experimentally confirmed at three selected radioactive isotope energies. Experimental measurements of mass attenuation coefficient follow the sequence: MACG1 > MACG2 > MACG3 > MACG4. Raman spectroscopy results indicate that the glass network primarily consists of silicate and phosphate species as the main structural units. An increase in the molar ratio of Na2O and P2O5 improves the radiation shielding effectiveness of the samples. Among them, sample G5, with the lowest SiO2 and MgO content, exhibits the best shielding characteristics due to its high density and molar fraction of Na2O and P2O5. A correlation between microhardness and protective effectiveness is also established. The obtained results support the potential use of these glasses as dual agents for both radiation shielding and medical devices simultaneously.

COMPARISON OF GAMMA–RAYS ATTENUATION MEASURED BY DIRECT AND COINCIDENCE SPECTRA

Measurements of gamma –rays attenuation in lead and iron sheets were carried out using direct spectrum and gamma- gamma fast slow coincidence spectrometer composed of two 3"×3"NaI(Tl) detectors and Na-22 source. Measurements of mass attenuation coefficient at 511keV were carried out and its values (in cm²/g units) for lead from direct spectrum for the cases of without and with using a collimator (1cm diameter and 5 cm length) were 0.12029 and 0.13591and from coincidence spectrum were 0.10721 and 0.10602 respectively. For iron sheets the mass attenuation coefficient values from direct spectrum for the cases of without and with using a collimator were 0.0780 and 0.0766 andfrom coincidence spectrum were 0.0593 and 0.0616 respectively. The present results registered by direct measurement are little lower than the standard values due to making only photoelectric absorption needed for comparison with coincidence results where the latter showed lower values.
 The build-up factor were also measured as function of thickness using lead and iron sheets and found fluctuating around unity for lead and iron coincidence spectra and iron direct spectrum, whereas its increases gradually for lead direct spectrum for the measured thickness range. The coincidence spectrometer greatly reduces scatteringevents in the measured material, and thus its results somewhat resemble that of direct measurements with using the collimator.

Effect of TeO2 addition on the gamma radiation shielding competence and mechanical properties of boro-tellurite glass: an experimental approach

We experimentally investigated the effect of TeO2 on the radiation-shielding competence of a BaO–MoO3–B2O3 glass system. Two gamma-ray sources (137Cs and 166Ho) and a scintillator detector (sodium iodide (NaI(Tl)) were utilized to measure the attenuation factors of the prepared glass at 0.184, 0.280, 0.662, 0.710, and 0.810 MeV. The measured mass attenuation coefficient agreed well with the theoretically calculated values for all the prepared samples. The linear attenuation coefficient (LAC) results demonstrated that as the photon energy increased, the penetrating ability of the photons through the glass increased. The LAC values of boro-tellurite glass at 662 keV were compared with those of other tellurite glass. We found that MTB1 glass produced better attenuation results than 10Li2O–20K2O–50B2O3–20TeO2 glass, whereas MTB5 glass with 70 mol% TeO2 had an LAC value greater than that of 90.4TeO2-9.6ZnO–4NiO glass. The half-value layer (HVL) increased continuously with photon energy. For MTB1 glass, the HVL increased from 0.3609 cm at 184 keV to 1.6078 cm at 662 keV and 1.8381 cm at 810 keV. The lowest set of HVL values was observed for MTB5 glass, which confirmed its superior attenuation properties compared to other compositions. The transmission factor (TF) was also calculated; MTB5 glass had the lowest TF values, which revealed that MTB5 provided the best shield. For glass with a thickness of 1 cm, the TF was 75.8% for MTB1, 72.8% for MTB2, 70.6% for MTB3, 68.8% for MTB4, and 63.4% for MTB5.

Epoxy-based Light Weight Gamma Ray Shielding Materials

Lightweight epoxy-based X-ray /gamma-ray shielding materials were synthesized by blending epoxy resin with the different weight percent of lead oxide, bismuth oxide, and tungsten oxide powders. The synthesized composites were characterized using FTIR, elemental analyzer, and X-ray radiography for their chemical structure, elemental composition, and filler distribution. The photon interaction parameters such as linear/mass attenuation coefficient, attenuation percentage, and half value layer were determined for all composites at photon energies 59.5, 364, and 661.7 keV. The measured mass attenuation coefficients of epoxy composites matched well with the obtained from XCOM. Moreover, the shielding effectiveness of the composites was analyzed by the half-value layer and heaviness of the composites and was compared with conventional shielding materials (concrete, lead, and steel).

Measurement of mass attenuation coefficient and its derivable in polymers

We have measured the mass attenuation coefficient (MAC) and its derivable such as linear attenuation coefficient (μ), half value layer (HVL), tenth value layer (TVL), free path (λ) and specific gamma ray constant (Γ) of some commonly used polymers (Polysterene, Polypropylene, PTFE, PVC, PCTFE, Technora, Zylon, Vectron, Mylar, Bekalite, Twaron and Orlon), Silicon polymers (Poly dimethyl siloxane, Polymethyl Hydro silaxane, Per hydro poly silaxane, Poly dimethyl silaxane, Methylsilses quioxane and Silalkalyene polymer), Co-ordination polymers (Lead monoclinic-(I), Lead monoclinic-(II), 2D Cadium co-ordination polymer, Azelato barium (II) polymer, 1-D Co-ordination barium polymer(I), Helical lead(II) Co-ordination polymer, Lead tetragonal , Calcium bromide polymer(I), Calcium bromide polymer(II) and 1D Cadmium co-ordination polymer), Boron polymers (Polyborazylene, 4- Vinylphenylboronic acid, Borazine, 3-Acrylamidophenylboronic acid, E-phenyl ethenyl boronic acid, 4-Aminophenylboronic acid and 3- Aminophenylboronic acid) and Lanthanide polymers (Lanthanum polymer, Cerium polymer, Praseodymium polymer, Gadolinium texaphyrin, Terbium co-ordination polymer and Erbium phosphate hydrate polymer) at different gamma energies such as 81, 276, 302.8, 356, 383.80, 511, 661.6, 835, 1173 and 1332 keV using various gamma sources such as Ba-133, Na-22, Cs-137, Mn-54, and Co-60. It is also observed that Lead tetragonal polymer is having larger μ/ρ and μ and smallest HVL and TVL. Thus, it can be concluded that the Lead tetragonal polymer is the best absorber of gamma radiation among all the investigated polymers. The measured data is tabulated and this can be considered standard data for polymers. The present work will be useful in the fields of Radiation Physics and shielding.

High-accuracy mass attenuation coefficients and X-ray absorption spectroscopy of zinc - the first X-ray Extended Range Technique-like experiment in Australia.

The first X-ray Extended Range Technique (XERT)-like experiment at the Australian Synchrotron, Australia, is presented. In this experiment X-ray mass attenuation coefficients are measured across an energy range including the zinc K-absorption edge and X-ray absorption fine structure (XAFS). These high-accuracy measurements are recorded at 496 energies from 8.51 keV to 11.59 keV. The XERT protocol dictates that systematic errors due to dark current nonlinearities, correction for blank measurements, full-foil mapping to characterize the absolute value of attenuation, scattering, harmonics and roughness are measured over an extended range of experimental parameter space. This results in data for better analysis, culminating in measurement of mass attenuation coefficients across the zinc K-edge to 0.023-0.036% accuracy. Dark current corrections are energy- and structure-dependent and the magnitude of correction reached 57% for thicker samples but was still large and significant for thin samples. Blank measurements scaled thin foil attenuation coefficients by 60-500%; and up to 90% even for thicker foils. Full-foil mapping and characterization corrected discrepancies between foils of up to 20%, rendering the possibility of absolute measurements of attenuation. Fluorescence scattering was also a major correction. Harmonics, roughness and bandwidth were explored. The energy was calibrated using standard reference foils. These results represent the most extensive and accurate measurements of zinc which enable investigations of discrepancies between current theory and experiments. This work was almost fully automated from this first experiment at the Australian Synchrotron, greatly increasing the possibility for large-scale studies using XERT.

High-accuracy measurement of mass attenuation coefficients and the imaginary component of the atomic form factor of zinc from 8.51 keV to 11.59 keV, and X-ray absorption fine structure with investigation of zinc theory and nanostructure.

High-accuracy X-ray mass attenuation coefficients were measured from the first X-ray Extended Range Technique (XERT)-like experiment at the Australian Synchrotron. Experimentally measured mass attenuation coefficients deviate by ∼50% from the theoretical values near the zinc absorption edge, suggesting that improvements in theoretical tabulations of mass attenuation coefficients are required to bring them into better agreement with experiment. Using these values the imaginary component of the atomic form factor of zinc was determined for all the measured photon energies. The zinc K-edge jump ratio and jump factor are determined and results raise significant questions regarding the definitions of quantities used and best practice for background subtraction prior to X-ray absorption fine-structure (XAFS) analysis. The XAFS analysis shows excellent agreement between the measured and tabulated values and yields bond lengths and nanostructure of zinc with uncertainties of from 0.1% to0.3% or 0.003 Å to 0.008 Å. Significant variation from the reported crystal structure was observed, suggesting local dynamic motion of the standard crystal lattice. XAFS is sensitive to dynamic correlated motion and in principle is capable of observing local dynamic motion beyond the reach of conventional crystallography. These results for the zinc absorption coefficient, XAFS and structure are the most accurate structural refinements of zinc at room temperature.

Physical properties and gamma radiation shielding capability of highly dense binary bismuth borate glasses

Dense glasses in the binary bismuth-borate system, xBi2O3-(1-x)B2O3 (BBO), x = 0.25, 0.5, & 0.75 were prepared by conventional melt-quenching process at different temperatures. The melt was hot pressed between the stainless-steel plates to obtain dense glasses. The glasses obtained were optically clear, thermally stable and amorphous in nature. Transparent BBO glasses exhibited high density in the range of 5.5–8.29 g/cm3 which is attributed to the high bismuth content and pressure induced compaction at high temperatures in the hot-pressed quenching. Gamma radiation shielding properties of the dense BBO glasses were investigated by calculating mass attenuation coefficients, effective atomic number, and different buildup factors. Radiation shielding properties were calculated using the XCOM and Phy-X web software as a function of photon energy for all the glasses. Experimental mass-attenuation coefficients at different energies of the BBO glasses were determined through radiation transmission method. Measured mass-attenuation coefficients of the BBO glasses were in close agreement with the calculated values. Further, exposure and energy absorption buildup factors of the dense BBO glasses were studied at different penetration depths as a function of the photon energy. The results were compared with the heavy-metal oxide glasses reported in the literature and with respect to lead metal shield. Dense binary bismuth glass exhibited high mass-attenuation coefficients, and low half-value layer, and mean-free path which are comparable with the metal lead. The dense binary bismuth borate glasses reported here can be the excellent radiation shielding transparent simple glass system and promising for the radiological applications.

Measurements of mass attenuation coefficients for 51Sb over energy region 4 keV–14 keV using synchrotron radiation

In the present work, the X-ray mass attenuation coefficients have been measured for 51Sb (a medium-Z element) at forty energies across its Li (i = 1–3) sub-shell absorption edges covering an extended energy region within 4.0 keV–14.0 keV. The aim of this study is to experimentally determine the key X-ray fundamental parameters for 51Sb with improved accuracy by using tunable energy synchrotron radiation. From the present measured mass attenuation coefficients, the Li (i = 1–3) sub-shell photoionization cross sections (σLiP) have been deduced at twenty four energies across the Li (i = 1–3) edge-energies of 51Sb covering the region 4.150 keV–5.0 keV by using experimentally deduced Li (i = 1–3) edge jump ratios. Two theoretical datasets of X-ray mass attenuation coefficients and total photoionization cross sections were served to evaluate their consistency with the present experimental values and reveal possible discrepancies, in particular, across the Li (i = 1–3) edge-energies of 51Sb.

High accuracy determination of photoelectric cross sections, X-ray absorption fine structure and nanostructure analysis of zinc selenide using the X-ray extended range technique.

Measurements of mass attenuation coefficients and X-ray absorption fine structure (XAFS) of zinc selenide (ZnSe) are reported to accuracies typically better than 0.13%. The high accuracy of the results presented here is due to our successful implementation of the X-ray extended range technique, a relatively new methodology, which can be set up on most synchrotron X-ray beamlines. 561 attenuation coefficients were recorded in the energy range 6.8-15 keV with measurements concentrated at the zinc and selenium pre-edge, near-edge and fine-structure absorption edge regions. This accuracy yielded detailed nanostructural analysis of room-temperature ZnSe with full uncertainty propagation. Bond lengths, accurate to 0.003 Å to 0.009 Å, or 0.1% to 0.3%, are plausible and physical. Small variation from a crystalline structure suggests local dynamic motion beyond that of a standard crystal lattice, noting that XAFS is sensitive todynamic correlated motion. The results obtained in this work are the most accurate to date with comparisons with theoretically determined values of the attenuation showing discrepancies from literature theory of up to 4%, motivating further investigation into the origin of such discrepancies.

Measurement of mass attenuation coefficient of polyvinyl alcohol (PVAL) as breast tissue equivalent material in the photon energy range of 16.61–25.26 keV

Medical physics phantom is commonly designed to mimic physical properties of human tissue. Phantom is widely used to provide quantitative and qualitative information upon its interaction with ionizing radiation in medical imaging, radiation dosimetry and treatment planning procedures. This study was carried out to fabricate a potential medical physics phantom material for mammography using polyvinyl alcohol (PVAL). The mass attenuation coefficients (μ/ρ ) of the PVAL gel samples were calculated based on the measurement of attenuation coefficient studies with low photon energy. The gel samples were prepared at 4 concentrations (5, 10, 15 and 20 %) of PVAL solution. Single photon beam transmission in the energy range between 16.61 and 25.26 keV was used to determine the μ/ρ of the PVAL gel. The low photon energy was chosen as the effective energy used in mammography is in a range between 17.5 to 22.6 keV. This was achieved by using the X-ray fluorescent (XRF) configuration. The experimental μ/ρ were compared with theoretical values of water and breast tissue calculated by using the XCOM computer program. The measured value of μ/ρ of the PVAL gels agreed with the XCOM values of water and breast tissue. The 5% and 10% PVAL gel samples were the closest to water while the 20% PVAL was the closest to breast tissue.

Synthesis, characterization and low energy photon attenuation studies of bone tissue substitutes

AbstractEpoxy composites with different weight percentages of calcium carbonate and calcium phosphate were synthesized as bone tissue substitutes (BTS) for internal dosimetry. The Fourier-transform infrared spectroscopy analysis confirmed that no chemical reaction occurred between the polymer and the fillers. Thermogravimetric analysis also showed improvement in the thermal properties of the composites due to the fillers. The uniform distribution of fillers in the epoxy matrix was established by X-ray radiography. The attenuation behavior of BTS was probed for low energy γ source 241Am (59.5 keV) using planar HPGe detector. The measured mass attenuation coefficients of BTS were found to match with the values calculated using XCOM software. The radiological properties derived for these composites were found to be on par with those of ICRU-44 cortical bone and B-100 bone equivalent plastic.

Measurement of Mass Attenuation Coefficients for Some Potassium Compounds

In this study, the mass attenuation coefficients of some potassium compounds (KH 2 PO 4 , KNO 3 , K 2 S 2 O 8 , KOH, K 2 HPO 4 , K 2 SO 4 , KCl, KIO 3, and KI) have been measured by using Energy Dispersive X-ray Fluorescence Spectrometer (EDXRFS) and a high-resolution Si(Li) detector. Obtained experimental mass attenuation coefficients have been compared with WinXCom and FFAST theoretical values.

Gamma-ray shielding characteristics of flexible silicone tungsten composites

Silicone being a hybrid elastomer is well known for its excellent thermal and mechanical properties, chemical resistance, compatibility with organic and inorganic fillers, nontoxicity, and flexibility. As the reported literature on silicone tungsten composite is rare, thus, a complete possible spectrum of silicone tungsten composites series with tungsten loading of 0–88.1 %wt has been fabricated by RTV method and studied as a flexible gamma shielding material. Flexible silicone/tungsten composite formulations containing different weight percentages of tungsten powder (0, 30.1, 47.8, 59.8, 68.1, and 88.1 wt %) were developed by the room-temperature vulcanization route. Two lead collimators with diameters of 0.6 cm were used to make a narrow beam geometry for gamma rays emitted from a137Cs (gamma-ray energy of 662 keV) point source. Uncollided flux was measured with a NaI(Tl) scintillation detector enclosed in lead shielding to reduce the background radiation level. The measured mass attenuation coefficient for our composites with 88.1 wt % tungsten was 0.1035 cm2/g, which is nearly 3.5% higher than that of commercially available silicone/tungsten composites named T-Flex (nearly 0.095 cm2/g) containing the same tungsten loading. Similarly, superior half value layers (HVL) of our composites with 88.1 % wt loading of tungsten i.e 1.01 cm versus 1.27 cm for the reported T-Flex counterpart with additional advantage of insitu fabrication on complex geometries. It was also found that the effectiveness of gamma-ray shielding increases with increase in density of the composites, which is due to the increase in the weight percent of tungsten powder. Our material will have applications as shielding material for both mobile and stationary radiation sources and it can also be used as fabrication material for gloves, safety shoes, coats, etc. to protect workers in a radiation environment.

X-ray fluorescent (XRF) configuration for the measurement of mass attenuation coefficients at low energy photons

An X-ray fluorescent (XRF) configuration was used to measure the mass attenuation coefficient of materials at low energy photons. An Americium-241 (241Am) annular source was used in conjunction with niobium, palladium, molybdenum and tin plates that provided Kα1 photons with energies between 16.59 and 25.26 keV. The transmitted photons were measured by using a low energy Germanium (LEGe) detector and analyzed by using MAESTRO software. A calibration with 241Am showed good linearity between photon energies and peak channels with R2 value near to 1. The measurement of mass attenuation coefficient was carried out on Al plates and Perspex based on the transmitted photons on the samples. The measured mass attenuation coefficients were compared to the XCOM calculations. The results showed that the measured mass attenuation coefficients of aluminum and Perspex® were in good agreement to their XCOM values within 10% percentage of discrepancies at all experimented photon energies. The overall results indicated the suitability of the XRF configuration for the measurement of mass attenuation coefficients at low energy photons.

Ludlum configuration for the measurement of mass attenuation coefficients at high energy photons by using Compton scattering method

The measurements of mass attenuation coefficients by using Compton scattering technique was carried out by using the Ludlum configuration. A 137Cs sealed sourced was used and attenuated at angles between 30 and 75° to provide scattered gamma energies between 337.72 and 564.09 keV. The mass attenuation coefficients of solid water and perspex were measured and compared to the calculated value of water by using XCOM. The results showed that the measured mass attenuation coefficients of solid water and Perspex® phantoms were in agreement to the values of water within 6.84 and 7.20% average percentage of discrepancies. The results indicated the suitability of the Ludlum configuration for the measurement of mass attenuation coefficients by using the Compton scattering method.

Measurement of mass attenuation coefficients of the fabricated Rhizophora spp. particleboards at high energy photons by using Compton scattering method

The mass attenuation coefficients of the fabricated Rhizophora spp. particleboards were measured by using the Compton scattering technique and Ludlum configurations. The mass attenuation coefficents of the particleboards were measured at scattered gamma energies of 137Cs between 337.72 and 564.09 keV and compared to the its theoretical values and the values of water by using XCOM calculation. The results showed that the measured mass attenuation coefficients of the fabricated Rhizophora spp. particleboards were in good agreement to its theoretical values and water (XCOM) within 3.8 and 5.9% discrepancies. The results showed the near attenuation properties of the fabricated Rhizophora spp. particleboards to water at scattered gamma energies and the suitability of the Ludlum configuration for the measurement of mass attenuation coefficients of materials.

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

The aim of this experimental study is to figure out the photon shielding performance of four alloys sample (Ag92.5/Cu7.5, Ag72/Cu28, Pd94/Cr6 and Pd60/Cu40). For this purpose, the shielding ability of these alloys against fourteen photon energies (in the energy range of 81–1333 keV) using six gamma-ray sources (22Na, 54Mn, 57Co, 60Co, 133Ba and 137Cs) was measured and compared with the results obtained by WinXCOM and MCNPX code. The results showed that the measured mass attenuation coefficient values for the four alloys coincide with those calculated by WinXCOM and MCNPX at all energies. The Ag92.5/Cu7.5 sample possesses the highest values of mass attenuation coefficient and effective atomic number. The tendency of the effective conductivity versus photon energy was found as the same as the electron density.

Measurement of mass attenuation coefficients, effective atomic numbers, and electron densities for different parts of medicinal aromatic plants in low-energy region

The mass attenuation coefficients (µ/ρ) for different parts (root, flower, stem, and leaf) of three medicinal aromatic plants (Teucrium chamaedrys L. subsp. sinuatum, Rheum ribes, and Chrysophthalmum montanum) were measured using an 241Am photon source in a stable geometry and calculated using the Monte Carlo N-Particle Transport Code System-extended (MCNPX) code and the WinXCOM program. The experimental and theoretical MCNPX and WinXCOM values exhibited good agreement. The measured mass attenuation coefficient values were then used to compute the effective atomic number (Zeff) and electron density (NE) of the samples. The results reveal that S1-S (stem of Teucrium chamaedrys L. subsp. sinuatum) has the highest values of µ/ρ and Zeff.