Total Cross Sections For Electron Research Articles

High-resolution and high-precision measurements of total cross section for electron scattering from CO$$_2$$

High-resolution and high-precision measurements of total cross section for electron scattering from CO$$_2$$

Electron Scattering from Methyl Formate (HCOOCH3): A Joint Theoretical and Experimental Study.

Elastic low-energy electron collisions with methyl formate have been studied theoretically at the level of various theories. The elastic integral cross section was calculated using Schwinger multichannel and R-matrix methods, in the static-exchange and static-exchange plus polarization levels of approximations for energies up to 15 eV. The absolute total cross section for electron scattering from methyl formate has been measured in a wide energy range (0.2-300 eV) using a 127° electron spectrometer working in the linear transmission configuration. The integral elastic and the absolute total cross sections display a π* shape resonance at around 1.70-1.84 eV, which can be related to the resonance visible for formic acid, and a broad structure located at 7-8 eV, which can be associated to a superposition of σ* shape resonances. Our results were compared with theoretical and experimental results available in the literature and with the results of electron collisions with formic acid. The additivity rule was used to estimate the total cross section of methyl formate and the results agree well with the experimental data.

Radiation Shielding Properties of Oxides (Al2O3, PbO and Fe2O3) based on Klein-Nishina Cross-section

In this study, we investigate the Klein-Nishina differential cross-section equation for total cross-section and extend it to calculate the total molecular cross-section for compounds Al2O3, PbO, and Fe2O3. Our findings reveal that the total molecular cross-section of these compounds is significantly larger, with values 5 times greater than the total atomic cross-section. Furthermore, we determine that the molecular cross-section of Al2O3, PbO, and Fe2O3 is 73, 132, and 118 times greater than the total electronic cross-section, respectively, while the atomic cross-section of these compounds is 15, 66, and 24 times greater. At low energy levels ranging from 1-5 MeV, the entire molecular, atomic, and electronic cross-section dominates due to Compton scattering. However, as the photon energy increases, Compton scattering becomes negligible, and a slight contribution from pair production scattering is observed. We also establish the adequate atomic numbers for Al2O3, PbO, and Fe2O3, which are determined to be 15, 66, and 24, respectively. These results highlight the significance of mass attenuation, cross-section, and adequate atomic number in the selection of radiation shielding materials for various protection purposes. The findings from this study provide valuable insights into the properties and behavior of these compounds, enabling informed decisions in radiation shielding applications.

A comprehensive analysis on radiation shielding characteristics of borogypsum (boron waste) by Phy-X/PSD code

In the present study, radiation shielding characteristics of the borogypsum, which is a waste generated during the boric acid production in Turkey, was analyzed. For this purpose, we used recently developed Phy-X/PSD software, which is provided to calculate shielding parameters such as mass attenuation coefficient, linear attenuation coefficient, half-value layer, tenth-value layer, effective atomic number, total atomic cross section, total electronic cross section, effective conductivity, effective electron number, buildup factors and fast neutron removal cross section in a wide photon energy range. Additionally, mass attenuation coefficients of borogypsum were compared with those of other radiation shielding materials (ordinary concrete, obsidian, pumice, clay) in order to give a significant evaluation about the radiation shielding capability of borogypsum. Half value layer and fast neutron removal cross section values are also evaluated by other materials. It is noticed that borogypsum has higher shielding potential than other reported shielding materials.

Gamma-ray attenuation parameters of HDPE filled with different nano-size and Bulk WO3

High-density polyethylene (HDPE) was obtained through a compression molding technique, and incorporated with different filler weight fractions (0, 10, 15, 25, and 35%) of bulk WO3, and two different WO3 nanoparticle sizes (45 nm and 24 nm). The radiation attenuation ability of the new category of polymer composite HDPE/WO3 was evaluated using gamma-ray energies ranging from 59.53 up to 1332.5keV of four radioactive sources 241Am, 133Ba, 137Cs, and 60Co. The mass attenuation coefficients μm, the total molecular cross-section σmol, the effective atomic cross-section σatom, the total electronic cross-section σel, the effective atomic number Zeff, electron density Neff, the half value layer (HVL), the tenth value layer (TVL), and the relaxation length were investigated. The obtained results of the gamma-ray attenuation parameters exhibited an outstanding influence of the size and weight fraction of WO3 filler on the gamma-ray shielding ability of the HDPE composite. A significant improvement was detected at low gamma-ray energies. The HVL of the synthesized HDPE composites is compared with that of pure lead as a conventional shielding material. HDPE composite filled with the smaller size of WO3 nanoparticle shows good improvement in the attenuation parameters, which suggests promising applications in radiation protection and gamma-ray shielding.

INVESTIGATION OF NUCLEAR RADIATION INTERACTION PARAMETERS OF NICKEL- BASED SHAPE MEMORY ALLOYS

In this study, the fast neutron removal cross section (FNRCS), mass attenuation coefficient (μ/ρ), half-value thickness (HVL), tenth value thickness (TVL), mean free path (λ), total electronic cross section (σte), totalmolecular cross section (σtm), effective atomic number (Zeff) and the effective electronic density (Neff) the valueswere calculated for nickel-based shape memory alloy at different energy. Important another nuclear attenuationparameter relevant to shielding i.e. the fast neutron removal cross section (FNRCS) was be calculated for alloys.NiTiPt possesses the best FNRCS (= 0.143) among the present studied alloys.

Observation of Transient Anions That Do Not Decay through Dissociative Electron Attachment: New Pathways for Radiosensitization.

Low-energy electrons (LEEs) can very efficiently induce bond breaking via dissociative electron attachment (DEA). While DEA is ubiquitous, the importance of other reactions initiated by LEEs remains much more elusive. Here, we looked into this question by measuring highly accurate total cross sections for electron scattering from 1-methyl-5-nitroimidazole (1M5NI), a model radiosensitizer. The small uncertainty and high energy resolution allow us to identify many resonant features related to the formation of transient anions. In addition to novel insights about DEA reactions through the lower-lying resonances, our key finding is that the higher-lying resonances do not undergo DEA, implying alternative decay channels with significant cross sections. In particular, dissociation into two neutral fragments is probably involved in the case of 1M5NI. This finding has direct implications for the understanding of LEE-induced chemistry, particularly in the fundamental processes underlying the radiosensitization activity.

Low energy electron scattering from pyridine using a Surko trap and beam

This paper presents measurements of low energy electron scattering from pyridine. The low energy positron beamline at the Australian National University was used for these measurements, with a change in operational parameters allowing for the measurement of electron scattering processes. We have collected data for the low energy total cross section for electron scattering, as well as measurements of the differential cross sections for electrons up to 3 eV impact energy. The operation of the beamline will be briefly outlined and data are compared to R-matrix and Schwinger multichannel theoretical calculations, as well as previous experimental data.

Total Cross Sections for Electron and Positron Scattering on Molecules: In Search of the Dispersion Relation

More than one hundred years of experimental and theoretical investigations of electron scattering in gases delivered cross-sections in a wide energy range, from few meV to keV. An analogy in optics, characterizing different materials, comes under the name of the dispersion relation, i.e., of the dependence of the refraction index on the light wavelength. The dispersion relation for electron (and positron) scattering was hypothesized in the 1970s, but without clear results. Here, we review experimental, theoretical, and semi-empirical cross-sections for N2, CO2, CH4, and CF4 in search of any hint for such a relation—unfortunately, without satisfactory conclusions.

Electron scattering from molecules relevant to Titan's atmosphere

Present article reports calculation of elastic, momentum transfer, ionization, and total cross sections for electron scattering from C2N2, C4N2, C6N2, and HC5N molecules, relevant to Titan's atmosphere. The cross sections are predicted using spherical complex optical potential and complex potential ionization contribution method in the energy range from ionization threshold of the molecules to 5 keV. The cross section data reported here consider geometrical screening correction to avoid overestimation of cross section due to the overlap of charge density. A strong correlation is observed between Qionmax and (α/I)12 for C2N2, C4N2, and C6N2 molecular systems, which confirms the consistency of predicted ionization data. The cross sections reported here are important for mass spectrometry, especially in modelling Titan's atmosphere due the presence of these molecules along with abundant electrons in its environment. Most of the data are reported for the first time.

Development of high-density radiation shielding materials containing BaSO4 and investigation of the gamma-ray attenuation properties

The high-density shielding materials containing higher percentage (>80%) of BaSO4 have been developed and their gamma-ray attenuation parameters have been investigated. Three samples have been prepared [Sample-1 (83.75%), Sample-2 (84.75%), and Sample-3 (82.75%)], their elemental composition has been determined by the EDX method, and the density has been measured experimentally for Sample-1 (3.362 g/cm3), Sample-2 (3.365 g/cm3), and Sample-3 (3.358 g/cm3). The mass attenuation coefficients (μ/ρ) have been calculated analytically in order to generate a database for the photon energy range from 1keV to 100MeV using WinXcom software. For validation, this parameter has been measured experimentally for gamma-ray emitted from 133Ba radioactive sources using HPGe detector (with relative efficiency ≈20% relative to a 3"×3"NaI(Tl) detector, and resolution 2.3keV at 1.33MeV γ-lines). The linear attenuation coefficient (μ), total atomic cross section (σa), total electronic cross section (σe), effective atomic number (Zeff), effective electron density (Neff), and relaxation length (λ) have been calculated for the same energy range. All parameters have been compared with the values for five different concretes namely barite, serpentine, ilmenite-magnetite, ordinary concrete, and basalt-magnetite. Transmission graphs have been drawn for some widely used radioactive sources. Sample-2 with the highest density (3.365 g/cm3) and comprising relatively higher atomic number elements is found to be the most effective shield for gamma-ray attenuation.

Measurement of Total Electronic Cross-Section, Total Atomic Cross-Section, Effective Atomic Numbers, Effective Electron Densities and Kerma for Some Br Compounds

The aim of this study is to calculate the experimental and theoretical the mass attenuation coefficient some Br compounds by using transmission method. Also using these values were determined the total electronic section, total atomic section, effective atomic number, effective electron density and Kerma. We performed the calculations of these values in attenuation by using direct excitation experimental geometry. The total attenuation cross sections of some halogene Br compounds were measured in a narrow beam good geometry using a high resolution Si(Li) detector in the energy with γ photons at 59.543 keV from Am-241 annular source. Theoretical mass attenuation coefficient values were computed from the XCOM data programme, based on mixture rule method. This study provide new insight into the literature since the values of effective atomic number, electron density and Kerma for some Br compounds have not been determined before. According to the results shown in mass attenuation coefficient, Zeff and Neff of Br compounds are closely associated with chemical structure. This research were undertaken to explore how Bromine compounds is gamma ray shielding material.

Prediction of mechanical and radiation parameters of glasses with high Bi2O3 concentration

This study aims to perform multidirectional characterizations on nuclear shielding efficiencies on some bismuth-based glasses. Accordingly, the γattenuation coefficients for xBi2O3-(75-x)B2O3–25Li2O (x = 0, 10, 20, 30, 40, 50, 60 the 70 mol%) were widely evaluated using simulations and theoretical methods. Linear attenuation coefficient (LAC) of the glasses was obtained by the Monte Carlo general-purpose simulation code FLUKA and compared with the XCOM database up to 15 MeV. Moreover, LAC values have been utilized to evaluate related parameters like mass attenuation coefficient (MAC), total molecular cross-section (σt), total atomic cross-section (σa), half-value layer (HVL), total electronic cross-section (σe), mean free path (MFP), effective atomic number (Zeff), and effective electron density (Neff). The results noted that the XCOM and FLUKA data of the shielding parameters are in great agreement. Relatively higher density (5.818 g/cm3), greater LAC, MAC, Zeff, and lower HVL, MFP values are achieved for 70Bi2O3-5B2O3–25Li2O glass. Accordingly, this glass sample is a better gamma shield.

Взаимодействие низкоэнергетических электронов с молекулами D-рибозы

Abstract– The interactions of low-energy electrons (<20 eV) with D-ribose molecules, namely, electron scattering and dissociative attachment, are studied. The results of these studies showed that the fragmentation of D-ribose molecules occurs effectively even at an electron energy close to zero. as well as in the energy range 5.50–9.50 eV. In the total cross section of electron scattering by molecules, resonance features at energies of 5.00–9.00 eV in the region of formation of ionic fragments C3H4O2–, C2H3O2–, OH–, associated with the destruction of molecular heterocycles, were experimentally discovered for the first time. The correlation of the features observed in the scattering and dissociative electron attachment cross sections is analyzed.

Measurement of Photon Matter Interaction Parameters for some Iodine Compounds

In this study, total atomic cross-section (σta), total moleculer cross-section (σtm) total electronic cross-section (σte), effective atomic number (Zeff), effective electron density (Neff) and Kerma (K) were determined both experimentally and theoretically values for some iodine compounds. Experimental mass attenuation coefficient (µ/ρ) values for some iodine compounds were calculated with the data obtained from the test results. The theoretical mass attenuation coefficient values of these compounds were calculated with the WinXCOM data program. Also, we have performed the measurements for the calculations of experimental values mass attenuation coefficient using direct transmission experimental geometry. The transmission photon intensity of halogene iodine compounds were measured in a narrow beam experiment geometry was used 59.543 keV γ-ray from an 241Am radioactive source. The tranmissions spectra from iodine compounds were recorded with a Si (Li) detector having a resolution of 155 eV FWHM at 5.9 keV (55Fe) and coupled to a 1024 channel analyzer through a spectroscopic amplifier. This study was provided that new insights into the literature since mass attenuation coefficient experimental values of some I compounds have not been determined previously. More research should be done to observe the changes in the chemical structure of iodine compounds with gamma-ray interaction. This study will shed light on further research.

Electron induced scattering cross section for pyrrole and its isomers

Elastic, ionization and total cross section for electron scattering from pyrrole and its isomers, viz. 2H-pyrrole, 3H-pyrrole, cycloprapanecarbonitrile, E-2 butenenitrile and Z-2 butenenitrile are reported in this article. These cross sections are calculated using the spherical complex optical potential formalism and the complex scattering potential-ionization contribution method in the energy range from the ionization threshold of the molecule to 5 keV. The geometric screening correction is used to reduce the overestimation of cross section due to overlap in charge distribution among atoms or group of atoms in the molecule. The isomeric effect through cross section values are also investigated in this work. The cross section data reported in this paper are key input for modeling Titan’s atmosphere due to the presence of pyrroles and abundant electrons in its medium.

Investigation of γ-ray attenuation coefficients, effective atomic number and electron density for ZnO/HDPE composite

Bulk and nano ZnO/HDPE composite with different weight fractions (10, 20, 30 and 40%) of ZnO as a filler were prepared and studied for radiation shielding properties against γ-ray. The structural, morphological and functional properties of the composites were identified using x-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infrared specrtroscopy (FTIR). The results confirmed the formation of ZnO nanoparticles with crystallite size of 27 nm and revealed their good dispersion within the polymer matrix compared to bulk ZnO as well as interaction mechanism between the filler and the polymer matrix. The mass attenuation coefficient (μm) for the composite was measured experimentally using a well calibrated high purity germanium cylindrical detector (HPGe) at energies (59.54, 356.01, 661.66, 1173.33 and 1332.50 keV) for different radioactive point sources (241Am, 133Ba, 137Cs and 60Co). The obtained attenuation coefficients were used to determine the values of total molecular cross section σmol, the total atomic cross section σatm (cm2/atom), total electronic cross-section σel (cm2/electron) effective atomic number Zeff, and effective electron number Neff. Using NIST XCOM photon cross section database, the theoretical radiation parameters were calculated for bulk ZnO/HDPE composite and compared with the experimental results of both bulk and nano ZnO/HDPE composite. The obtained results revealed good agreement compared to theoretical values. μm, σmol, and σatm values decreased with incident photon energy and increased with weight percentage of both bulk and nano ZnO filler. However, these values were greater for nano ZnO/HDPE composite compared to bulk ZnO/HDPE composite with the same weight percentage. Whereas, σel, Zeff and Neff values decreased with weight percentage and revealed a plateau region which appeared with further increase in energy.

Low-Energy Electron Elastic Total Cross Sections for Ho, Er, Tm, Yb, Lu, and Hf Atoms

The robust Regge-pole methodology wherein is fully embedded the essential electron-electron correlation effects and the vital core polarization interaction has been used to explore negative ion formation in the large lanthanide Ho, Er, Tm, Yb, Lu, and Hf atoms through the electron elastic total cross sections (TCSs) calculations. These TCSs are characterized generally by dramatically sharp resonances manifesting ground, metastable, and excited negative ion formation during the collisions, Ramsauer-Townsend minima, and shape resonances. The novelty and generality of the Regge-pole approach is in the extraction of the negative ion binding energies (BEs) of complex heavy systems from the calculated electron TCSs. The extracted anionic BEs from the ground state TCSs for Ho, Er, Tm, Yb, Lu, and Hf atoms are 3.51 eV, 3.53 eV, 3.36 eV, 3.49 eV, 4.09 eV and 1.68 eV, respectively. The TCSs are presented and the extracted from the ground; metastable and excited anionic states BEs are compared with the available measured and/or calculated electron affinities. We conclude with a remark on the existing inconsistencies in the meaning of the electron affinity among the various measurements and/or calculations in the investigated atoms and make a recommendation to resolve the ambiguity.

Estimation of gamma-rays, and fast and the thermal neutrons attenuation characteristics for bismuth tellurite and bismuth boro-tellurite glass systems

Gamma-rays and fast and thermal neutron attenuation features of (Bi2O3)x–(TeO2)(100−x) (where x = 5, 8, 10, 12, and 15 mol%) and [(TeO2)0.7–(B2O3)0.3](1−x)–(Bi2O3)x (where x = 0.05, 0.10, 0,15, 0.20, 0.25, and 0.3 mol%) glass systems have been explored and compared. For all samples, mass attenuation coefficients (μ/ρ) are estimated within 0.015–15 MeV photon energy range by MCNP5 simulation code and correlated with WinXCom results, which showed a satisfactory agreement between computed μ/ρ values by these both methods. Additionally, effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), total atomic cross-section (σa), and total electronic cross-section (σe) are calculated by utilizing μ/ρ values. The μ/ρ, Zeff, and Neff are energy dependent and have higher values at the lowest energy and smaller values at higher energies. Moreover, using the G–P fitting method as a function of penetration depth (up to 40 mfp) and incident photon energy (0.015–15 MeV range), exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) are evaluated. Both 85TeO2–15Bi2O3 (mol%) and 49TeO2–21B2O3–30Bi2O3 (mol%) samples, by possessing higher values of Zeff, exhibit minimum EBF and EABF values. Highest μ/ρ, Zeff values and lowest HVL, TVL, MFP values of 49TeO2–21B2O3–30Bi2O3 (mol%) sample indicated its better gamma-ray absorption capability among all selected glasses. Further, macroscopic effective removal cross-section for fast neutrons (ΣR), coherent scattering cross-section (σcs), incoherent scattering cross-section (σics), absorption cross-section (σA), and total cross-section (σT) values for thermal neutron attenuation have been computed. Among all samples, 49TeO2–21B2O3–30Bi2O3 (mol%) glass possesses a better ΣR value for fast neutron attenuation, while the largest ‘σT’ value of 66.5TeO2–28.5B2O3–5Bi2O3 (mol%) sample suggests its good thermal neutron absorption efficiency.

Total cross section measurements for electron scattering from tin(IV) chloride (SnCl4)

SynopsisTotal cross section for electron scattering from SnCl4 molecules has been measured for energies from 0.6 to 300 eV. Obtained results have been compared with total cross sections for electron scattering from other tetrachoride molecules: XCl4 where X=C, Si, Ge.