Values Of Differential Cross Sections Research Articles

Investigating theoretical and experimental cross sections for elastic electron scattering from isoflurane.

We present a comprehensive analysis of elastic electron scattering from isoflurane in the intermediate energy range of 50-300 eV. This research is motivated by the significant impact of this molecule on global warming effects. We conducted this investigation through experimental measurements using a crossed-beam apparatus and covering a wide angular range from 25 to 125 degrees. Relative differential cross sections (DCSs) were obtained and subsequently normalized on an absolute scale by using the relative flow technique, with argon as the reference gas. These DCS values were then extrapolated and integrated to determine the experimental integral cross sections (ICSs). Additionally, we employed the independent atom model and the screening corrected additivity rule with incorporated Interference effects (IAM-SCAR+I) to calculate the theoretical differential and integral cross-sections. Remarkably, the calculated cross sections align closely with the experimental measurements across the entire energy and angular range. Furthermore, this study involved a comparison of the DCSs for isoflurane with previously published DCS values for two other volatile anesthetics, sevoflurane and halothane.

Differential cross–section measurements and R-Matrix calculations for proton elastic scattering on natMg in the energy range Ep,lab = 2.70–4.25 MeV, suitable for EBS

In the current work the first coherent set of differential cross section values for the natMg(p,p0)natMg elastic scattering covering the Ep,lab = 2700–4250 keV energy range is presented for 6 backscattering detection angles (120°, 130°, 140°, 150°, 160° and 170°). R-Matrix calculations were implemented using the AZURE 2.0 code [1] in an attempt to reproduce the obtained experimental data, whilst taking into account the 24Mg(p,p1)24Mg reaction channel. Both results are suitable for EBS and other IBA applications and, furthermore, they form a basis for a future expansion of the current SigmaCalc [2] evaluation, once more experimental data become available. The measurements were performed in the 5.5 MV TN11 HV Tandem Accelerator and the high precision goniometer of N.C.S.R. ‘Demokritos’, Athens, Greece. The experimental and data analysis procedures are presented in detail, along with the process behind the implementation of the R-Matrix calculations.

Differential Cross-section Measurements for 3He Elastic Scattering on 16O and 27Al

In the present work measurements to determine the differential cross section values for the elastic scattering of 3He on 16O and 27Al were carried out at the Ruđer Bošković Institute (RBI) Tandem Accelerator Facility in Zagreb, Croatia, covering the E3He,lab=3500-5600 keV energy range, using four Silicon Surface Barrier (SSB) detectors positioned at the backscattering angles of 130°, 145°, 157.7° and 165ο. The target was constructed at the facility and was comprised of a thin, self-supporting aluminum foil, upon which a thin layer of natB (isotopic ratio: 11B 80.1%, 10B 19.9%), along with 12C, 14N, 16O, was deposited using the sputtering technique. In addition, an ultra-thin layer of 197Au was evaporated on top for wear protection and normalization purposes.

Measurement of proton induced γ-ray emission cross sections on Cu for Ep < 3 MeV

Standardless PIGE analysis requires precise differential cross section values. In this research differential cross section data for proton-induced gamma-ray emission for 63Cu and 65Cu in the energy range 2000–3000 keV at 90◦ in the laboratory frame was measured. The research was carried out using the proton beam of the 3 MV Van de Graaff electrostatic accelerator of Nuclear Science and Technology Research Institute (NSTRI) in Tehran. The validity of present data was confirmed through thick target yield benchmarking procedure. The estimated systematic uncertainty is less than 9%.

Elastic and absorption electron collisions with acetaldehyde

We report a theoretical–experimental investigation on elastic electron scattering by acetaldehyde (CH $$_3$$ CHO) in the 0.5–800 eV energy range. Theoretically, the Pade approximation and the single-center partial-wave expansion method were applied to solve the Lippmann–Schwinger scattering equation, whereas a molecular complex optical potential was used to describe the electron–molecule interaction. Calculations in the independent-atom framework were also performed. Angular distributions of the elastically scattered electrons were measured in the 10 $$^{\circ }$$ –130 $$^{\circ }$$ and 30–800 eV ranges using a crossed beams geometry. Absolute values of differential cross sections were derived by the relative flow technique. In addition, integral and momentum transfer cross sections were obtained from the experimental and theoretical differential cross sections via a numerical integration procedure. Comparison between our results and previous experimental and theoretical calculations is made.

Differential cross-section measurements for proton elastic scattering on natSi in the energy range Ep,lab = 3–5 MeV, suitable for EBS

The differential cross section values of the natSi(p,p0) elastic scattering were determined in the energy range of Ep,lab = 3000–5000 keV at 6 backscattering detection angles (120°, 130°, 140°, 1 50°, 160° and 170°). The target was a self-supported thin Si3N4 foil. In addition, a thick crystalline silicon wafer was irradiated on its unpolished side with protons at energies Ep,lab = 3200, 3400, 3600, 3850, 4100, 4300, 4500, 4740, 5000 keV, in order to validate the results of the first experiment. On top of both targets a thin layer of 197Au was evaporated for normalization purposes. Both measurements were performed in parallel, using the 5.5 MV TN11 HV Tandem Accelerator and the high precision goniometer of N.C.S.R. ‘Demokritos’, Athens, Greece. The experimental and data analysis processes are presented in detail, as well as, comparisons between the obtained differential cross sections and already existing datasets in literature, along with the benchmarking results.

Elastic scattering and electronic excitation in positron interactions with neon

We report measurements of low energy positron scattering from neon, with the first measurements of absolute differential cross sections (DCSs) and of state-selective electronic excitation. These measurements are compared to calculations using the relativistic optical potential (ROP) technique, as well as other recently published theoretical calculations. At the lowest energies, experimental DCS data are fitted to extract scattering phase shifts, which can be compared to theoretical values and also used to generate DCS values over the full angular range. For the most part we find good accord in the two descriptions of the scattering processes, with some key disagreements. An analysis of possible sources of systematic error has also been presented, in light of the discrepancies.

Differential elastic scattering cross sections for deuterons on 9Be, at energies and angles suitable for elastic backscattering spectroscopy

The differential cross sections of the 9Be(d,d0) elastic scattering were determined in the present work in the energy range of Ed,lab = 1600–2200 keV in variable steps, mainly 20 keV at five backscattering angles (120°, 140°, 150°, 160° and 170°). The measurements were performed at the 5.5 MV TN11 HV Tandem Accelerator of the N.C.S.R. “Demokritos” implementing a high precision goniometer. The target used was a thin Si3N4 substrate with a beryllium layer on top. The obtained differential cross section values are compared to the ones existing in literature and the observed similarities and discrepancies are discussed.

First results of the differential cross sections of 9Be(d,d0) at energies and angles suitable for Elastic Backscattering Spectroscopy

The differential cross sections of the 9Be(d,d0) elastic scattering were determined in the present work in the energy range of Ed,lab = 740 - 2200 keV in variable steps, mainly 20 keV at five backscattering angles (120o, 140o, 150o, 160o and 170o). The measurements were performed at the 5.5 MV TN11 HV Tandem Accelerator of the N.C.S.R. “Demokritos” implementing a high precision goniometer. The target used was a thin Si3N4 target with a Beryllium layer on top. The obtained differential cross section values are compared to the ones existing in literature and the observed similarities and discrepancies are discussed.

Measurements of elastic scattering cross sections for 25.2, 28.5, 37.4, 36.8, and 42.2 keV X‐ray photons in elements with 22 ≤ Z ≤ 83

The differential elastic scattering cross sections were measured for 25.2 (Sn‐Kα), 28.5 (Sn‐Kβ1,3), 37.4 (Nd‐Kα1), 36.8 (Nd‐Kα2), and 42.2 (Nd‐Kα1,3) keV X‐ray photons at 139° scattering angle in elements with 22 ≤ Z ≤ 83. The measurement was done in reflection mode experimental setup involving 50Sn/60Nd secondary targets excited with 241Am radioisotope. The scattered X‐ray photons were detected using a high‐resolution low energy germanium detector (horizontal configuration, FWHM = 300 eV at 59.5 keV) coupled with computerized multichannel analyzer. The intensity of X‐ray photons along with geometrical factors were calculated from the theoretical knowledge of K X‐ray fluorescence cross sections and measured K X‐ray yields from excited targets. The measured values of differential cross sections were compared with the theoretical available values based on form factor and second‐order S‐matrix (SM) approaches. The experimental values of cross sections exhibit a large deviation from modified form (MF) values for the elements with BK/Ein ≈1, where BK is the K‐shell binding energy of electrons and Ein is the energy of incident photon. These deviations in experiment results were smooth out by the inclusion of anomalous scattering factors (ASFs) to the MF values. The measured elastic cross sections were found to be ~7% lower than MFASF values and agree with SM values for all elements under investigation.

Differential cross section measurement of the natO(d,d0) reaction at energies and angles relevant to EBS

In the present work, differential cross section values of the 16O(d,d0) reaction were obtained for Ed,lab=900–2000keV, at four scattering angles, namely at 90°, 135°, 150° and 165° using a thin SiO target having a thickness of (910±36)×1015at/cm2. The cross section values were determined with an energy step of ∼10keV while, the detailed measurements were carried out with an energy step of ∼5keV around the resonance peaks. The results were compared with those of the previous studies.

Electron-impact excitation of silver

We measure the differential cross sections (DCSs) for the electron-impact excitation of the combined (two fine-structure levels) resonant $4{d}^{10}5p\phantom{\rule{0.16em}{0ex}}^{2}P_{1/2,3/2}$ and $4{d}^{9}5{s}^{2}\phantom{\rule{0.16em}{0ex}}^{2}D_{5/2}$ states in silver from the $4{d}^{10}5s\phantom{\rule{0.16em}{0ex}}^{2}S_{1/2}$ ground state. A comparison with the predictions of the relativistic distorted-wave (RDW) approximation model is carried out. Relativistic distorted-wave calculations are performed for each level separately and are combined to compare with the measurements. Both the experimental and theoretical results are obtained at incident electron energies ${E}_{0}$ of 10, 20, 40, 60, 80, and 100 eV and scattering angles \ensuremath{\theta} from 10\ifmmode^\circ\else\textdegree\fi{} up to 150\ifmmode^\circ\else\textdegree\fi{} (experiment) and from 0\ifmmode^\circ\else\textdegree\fi{} to 180\ifmmode^\circ\else\textdegree\fi{} (calculations). Absolute values for the experimental DCSs are obtained by normalizing relative DCSs to theoretical RDW results at 40\ifmmode^\circ\else\textdegree\fi{} at all energies except at 10 eV, where we performed the normalization of the relative DCSs at 10\ifmmode^\circ\else\textdegree\fi{} to our previous small-angle experimental DCS values [S. D. To\ifmmode \check{s}\else \v{s}\fi{}i\ifmmode \acute{c}\else \'{c}\fi{} et al., Nucl. Instrum. Methods Phys. Res. Sect. B 279, 53 (2012)]. The integrated cross sections, which include integral ${Q}_{\mathrm{I}}$, momentum transfer ${Q}_{\mathrm{M}}$, and viscosity ${Q}_{\mathrm{V}}$ cross sections, are determined by numerical integration of the absolute DCSs.

Electron-indium atom scattering and analysis of electron and optical spectra

Experimental study of indium atom using electron and optical spectroscopy is presented in this paper. Both experimental techniques including experimental setups are described. Differential and integrated cross sections on elastic and inelastic electron scattering by indium atom are measured using electron spectrometer. The measurements are performed at incident electron energies of E0 = 10, 20, 40, 60, 80 and 100 eV within the large scattering angles ranging from 10° to 150° in steps of 10°. The experimental results are presented and comparison with the values predicted by calculated optical potentials method is conducted, showing good agreement. The differential cross sections (DCSs) for electron-impact excitation of the resonant state 6s 2S1/2 of Indium atom are measured at small and large angles. The forward scattering function method has been used for normalizing the generalized oscillator strengths (GOS) to determine optical oscillator strength and obtaining the absolute DCS values. Optical spectrum of In I and In II lines has been acquired by a streak camera. The experimental results regarding indium lines obtained by time resolved laser induced breakdown spectroscopy (LIBS) could be useful for obtaining the important plasma parameters such as temperature, electron density as well as plasma-expansion velocity and plasma starting times.

Near-threshold electron impact excitation of the argon 3p54s configuration-–new and revised normalized differential cross sections using recent time-of-flight measurements for normalization

Revised electron impact differential cross section (DCS) for excitation of the four levels comprising the 3p54s configuration of argon and their sum are reported for incident electron energies of 12.5, 13.0, 14.0, 14.5, 15.0, 15.5, 15.76, 16.0, 16.75, 17.5 and 20 eV. These cross sections were obtained using two conventional high-resolution electron spectrometers, but normalized where possible to recent inelastic-to-elastic scattering DCS ratios of the time-of-flight (TOF) measurements by Mondal et al (2009 PMC Phys. B 2 3). We also present results from new calculations of these DCSs using the B-spline R-matrix method (Zatsarinny and Bartschat 2004 J. Phys. B: At. Mol. Opt. Phys. 37 4693). Comparisons with earlier experimental DCS results are made, and we provide correction factors for the argon DCS values of Khakoo et al (2004 J. Phys. B: At. Mol. Opt. Phys. 37 247), based on TOF measurements.

Resonant vibrational excitation ofH2by electron impact: Full-range differential cross sections

Electron-impact vibrational excitation of the hydrogen molecule has been revisited in the energy region from 1 to 5 eV. A crossed-beam double trochoidal electron spectrometer is used. Forward and backward scattered electrons from the v=0{yields}1 excitation channel are separated by electron-beam modulation and time-of-flight detection technique. Present results are normalized and absolute values of differential cross sections at critical border angles of 0 deg. and 180 deg. are determined. In this way the differential cross-section measurements are completed in the full angular range from 0 deg. to 180 deg.

Measurement of then-pelastic scattering angular distribution atEn=14.9MeV

The relative cross sections for scattering of neutrons by protons have been measured at ${E}_{n}=10 \mathrm{MeV}$ for center-of-mass neutron scattering angles from $60\ifmmode^\circ\else\textdegree\fi{}$ to 180\ifmmode^\circ\else\textdegree\fi{}. Absolute differential cross section values were obtained by normalizing the angle-integrated relative angular distribution to the $n\ensuremath{-}p$ total cross section. The angular distribution exhibits a backward enhancement consistent with an exchange component of the $n\ensuremath{-}p$ interaction at this energy. The relative shape of the angular distribution is in good agreement with the prediction of the charge-dependent Bonn and Nijmegen potential models and with the Arndt phase-shift analysis. Better agreement is found with the evaluated nuclear data files (ENDF)/B-V than with the ENDF/B-VI evaluation.

Estimating the Raman Cross Sections of Single Carbon Nanotubes

The order of magnitude of Raman differential cross sections of radial breathing modes (RBMs) of individual carbon nanotubes is measured for 633 and 785 nm laser excitations. This is shown by both a calibration applied to previously published data from other authors at 785 nm and our own measurements of individual nanotubes at 633 nm excitation. We find typical values of differential cross sections of RBMs to be on the order of approximately 10(-22) cm(2)/sr for resonant nanotubes on a silicon substrate. This study therefore provides a rigorous quantification of the accepted view that Raman cross sections of carbon nanotubes are "huge".

Determination of differential cross-sections for the natK(p,p0) and 39K(p,α0) reactions in the backscattering geometry

Abstract In the present work, new, differential cross-section values are presented for the nat K( p , p 0 ) reaction in the energy range E lab = 3000–5000 keV (with an energy step of 25 keV) and for detector angles between 140° and 170° (with an angular step of 10°). A qualitative discussion of the observed cross-section variations through the influence of strong, closely spaced resonances in the p + 39 K system is also presented. Information has also been extracted concerning the 39 K( p , α 0 ) reaction for E lab = 4000–5000 keV in the same angular range. As a result, more than ∼500 data points will soon be available to the scientific community through IBANDL (Ion Beam Analysis Nuclear Data Library – http://www-nds.iaea.org/ibandl/ ) and could thus be incorporated in widely used IBA algorithms (e.g. SIMNRA, WINDF, etc.) for potassium depth profiling at relatively high proton beam energies.

Electron impact excitation of the 6s 2S1/2 state of In atom at small scattering angles

We measured the differential cross sections (DCSs) for the electron-impact excitation of the resonance transition 5p2P1/2–6s2S1/2 of In atom at small scattering angles using a crossed electron–atom beam technique. The incident electron energies were E0=10, 20, 40, 60, 80 and 100eV, while the small scattering angles ranged from 1° to 10° in steps of 1°. The forward scattering function method has been used for normalizing the generalized oscillator strengths (GOS) to the known optical oscillator strength and obtaining the absolute DCS values.

Differential cross-section measurements for the 12C(d, p0)13C reaction and applications to surface analysis of materials

This work involves surface analysis by nuclear techniques, which are non-destructive, and computer simulation. The “energy analysis” method for nuclear reaction analysis is used. Energy spectra are computer simulated and compared to experimental data, giving target composition and concentration profile information. Measured values are presented for the differential cross-section of the 12C(d,p0)13C reaction in the deuteron energy range 0.81–2.07MeV for laboratory detection angles of 165° and 135°, using self-supported two-layered targets consisting of high purity thin films of typically 13μg/cm2 natural carbon and 65μg/cm2 gold. The error in the absolute differential cross-section values is generally ∼6%. The method, using these values, is successfully applied to determination of uniform concentration profiles of 12C, along considerable depths, for a thick flat target of high purity pyrolitic graphite. It is characterised a thin surface film of carbon on a thick flat quartz target. Uniform concentration profiles of 16O are also obtained from (d,p) and (d,α) reactions.