Elastic Scattering Of Protons Research Articles

Nuclear Force Imprints Revealed on the Elastic Scattering of Protons with ^{10}C.

How does nature hold together protons and neutrons to form the wide variety of complex nuclei in the Universe? Describing many-nucleon systems from the fundamental theory of quantum chromodynamics has been the greatest challenge in answering this question. The chiral effective field theory description of the nuclear force now makes this possible but requires certain parameters that are not uniquely determined. Defining the nuclear force needs identification of observables sensitive to the different parametrizations. From a measurement of proton elastic scattering on ^{10}C at TRIUMF and abinitio nuclear reaction calculations, we show that the shape and magnitude of the measured differential cross section is strongly sensitive to the nuclear force prescription.

Proton Momentum Distributions and Elastic Electron Scattering form Factors for Some Even-A 1f-2p Shell Nucle

Proton Momentum Distributions and Elastic Electron Scattering form Factors for Some Even-A 1f-2p Shell Nucle

Quantitative plasma-fuel and impurity profiling in thick plasma-deposited layers by means of micro ion beam analysis and SIMS

The operation of the Joint European Torus (JET) with full-carbon wall during the last decades has proven the importance of material re-deposition processes in remote areas of the tokamak. The thickness of the deposits in shadowed areas can reach 1mm. The main constituent is carbon, with little inclusion of Inconel components. Atomic fractions Be/C and D/C can locally reach 1. Three methods were used to study thick deposits on JET divertor surfaces: (i) NRA analysis with a 15μm wide, 3MeV 3He ion microbeam on a polished cross section of the layer to determine the concentration distribution of D, Be and C and the distribution of Ni by particle induced X-ray emission; (ii) elastic proton scattering (EPS) from the top of the layers with a broad proton beam at 3.5 and 4.6MeV. These methods were absolutely calibrated using thick elemental targets. (iii) Depth profiling of D, Be and Ni was done with secondary ion mass spectrometry (SIMS), sputtering the layers from the surface. The three methods are complementary. The thickest layers are accessible only by microbeam mapping of the cross sections, albeit with limited spatial resolution. The SIMS has the best depth resolution, but is difficult for absolute quantification and is limited in accessible depth. The probed depth with proton backscattering is limited to about 30μm. The combination of all three methods provided a coherent picture of the layer composition. It was possible to correlate the SIMS profiling results to quantitative data obtained by the microbeam method.

Proton Elastic Scattering of23,25F

Proton elastic scatterings of neutron-rich nuclei 23F and 25F have been measured for the first time at 289 and 298 MeV/nucleon, respectively, using the MUST2 silicon strip detector array and RIBF facility at RIKEN. The differential cross section of 25F was found to be smaller than the calculation with the global potential by Koning and Deraloche. The small cross section of 25F can be well reproduced by an optical model calculation with a shallow and long-tail potential.

Intranuclear cascade model including collective excitations and trajectory deflections for (p,p′x)reactions around 50 MeV

Collective excitations and trajectory deflection are investigated to lower the applicable energy range of the intranuclear cascade model to around 50 MeV. First, inclusive $(p,{p}^{\ensuremath{'}}x)$ reaction processes that lead to noncollective and collective excitations are formulated under the Born approximation. Then, collective excitations and trajectory deflection are introduced into the framework of the intranuclear cascade model. As collective excitations, low-energy vibrational excitations and giant resonances are considered. The trajectory deflection is assumed to be given by the experimental angular distribution of proton-nucleus elastic scattering. Finally, numerical calculations are conducted for $(p,{p}^{\ensuremath{'}}x)$ reactions on ${}^{56}$Fe at 29.9 and 61.5 MeV. The predictive capability of the proposed model is validated through comparison with experimental observations. The proposed model gives reasonably good predictions of $(p,{p}^{\ensuremath{'}}x)$ reactions and proton elastic scatterings.

New Measurement of Proton Transfer Reactions and Elastic Scattering for 7Li + 13C at 34 MeV

The 13C(7Li, 6He)14N reaction is measured at E(7Li) = 34 MeV with the Q3D magnetic spectrometer of HI-13 tandem accelerator. Angular distributions at forward angles for proton transfer to the ground and the first excited states in 14N are obtained. In addition, angular distribution for 7Li + 13C elastic scattering is also measured. The optical potential parameters for the entrance and exit channels of the transfer reactions are derived by fitting the 7Li + 13C and 6Li + 14N elastic scattering experimental data, and their angular distributions are well reproduced by the distorted wave Born approximation calculations. A phase shift of about 2° between the calculations and the experiment data has been found in the earlier (7Li, 6He) study, whereas no such phase shift is observed in the present work.

Proton Elastic Scattering from 58Ni and 90Zr at Intermediate Energy

Elastic proton scattering at energies between 160 and 800 MeV from 58Ni and 90Zr has been studied within the global Dirac optical model. In this work we calculate potential parameters which give good fits to the experimental data using parameterization code comprising differential cross section and analysing power measurements using DWUCK4. The real and imaginary potentials are well determined and behave regularly with energy. The behaviour of the real central effective potential shows the development of a wine-bottle shape in the transition energy region and the persistence of a small attractive potential in the nuclear surface region, even at 800 MeV.

Complete Set of Deuteron Analyzing Powers for Deuteron–Proton Elastic Scattering at 250 MeV/nucleon and Three-Nucleon Forces

Measurements of a complete set of deuteron analyzing powers (iT11, T20, T21, and T22) for elastic deuteron-proton scattering at 250 MeV/nucleon have been performed with polarized deuteron beams at RIKEN RI Beam Factory. The obtained data are compared with Faddeev calculations based on the modern nucleon–nucleon forces together with the Tucson- Melbourne'99 and UrbanaIX three-nucleon forces.

Phenomenological and Semi-microscopic Analysis for Elastic Scattering of Protons on 6,7Li

Phenomenological and Semi-microscopic Analysis for Elastic Scattering of Protons on 6,7Li

Quantitative analysis of a metalloprotein compositional stoichiometry with PIXE and PESA

An absolute measurement of the heavy element concentrations in a dried sample of aqueous protein solution has been combined with the absolute measurement of protein molecular concentration in the same sample. The ratio of these two measurements yields the metal-to-protein compositional stoichiometry of the metalloprotein. This combination of two Ion Beam Analysis techniques (Particle-Induced X-ray Emission and Proton Elastic Scattering Analysis) allows quantitative assessment of the metal atom to protein ratio in metalloproteins without direct measurement of sulfur atoms within the protein for the first time. While these results only demonstrate success with a single well-known metalloprotein, this combination of measurement ratios holds promise for future Ion Beam Analysis studies of metalloproteins.

Comparative Analysis of Urban Atmospheric Aerosol by Particle-Induced X-ray Emission (PIXE), Proton Elastic Scattering Analysis (PESA), and Aerosol Mass Spectrometry (AMS)

A multifaceted approach to atmospheric aerosol analysis is often desirable in field studies where an understanding of technical comparability among different measurement techniques is essential. Herein, we report quantitative intercomparisons of particle-induced X-ray emission (PIXE) and proton elastic scattering analysis (PESA), performed of fline under a vacuum, with analysis by aerosol mass spectrometry (AMS) carried out in real-time during the MCMA-2003 Field Campaign in the Mexico City Metropolitan Area. Good agreement was observed for mass concentrations of PIXE-measured sulfur (assuming it was dominated by SO4(2-)) and AMS-measured sulfate during most of the campaign. PESA-measured hydrogen mass was separated into sulfate H and organic H mass fractions, assuming the only major contributions were (NH4)2SO4 and organic compounds. Comparison of the organic H mass with AMS organic aerosol measurements indicates that about 75% of the mass of these species evaporated under a vacuum. However approximately 25% of the organics does remain under a vacuum, which is only possible with low-vapor-pressure compounds, and which supports the presence of high-molecular-weight or highly oxidized organics consistent with atmospheric aging. Approximately 10% of the chloride detected by AMS was measured by PIXE, possibly in the form of metal-chloride complexes, while the majority of Cl was likely present as more volatile species including NH4Cl. This is the first comparison of PIXE/PESA and AMS and, to our knowledge, also the first report of PESA hydrogen measurements for urban organic aerosols.

The size- and time-resolved composition of aerosols from a sub-Arctic boreal forest prescribed burn

Aerosols from wildfires are the primary aerosols in the Arctic atmosphere during the summer months. These aerosols occur in large, increasing quantities and impact the sensitive radiative balance in the Arctic. FROSTFIRE, a controlled burn in a Long-Term Ecological Research Area 50 km north of Fairbanks, Alaska, was designed to quantify the impacts of wildfire on sub-Arctic boreal forest ecosystems in permafrost regions. However, it provided a unique opportunity to examine smoke aerosols collected in the middle of a sub-Arctic boreal forest fire. A battery-powered eight-stage aerosol impactor (i.e. a Davis Rotating-drum Unit for Monitoring), mounted at the top of a 10 m meteorological tower in the burn zone, collected size- and time-resolved aerosol samples with 19.45 min resolution for 24 h during the burn. The samples underwent Proton Induced X-ray Emission (PIXE) and Proton Elastic Scattering Analysis (PESA) to determine the sizes and elemental compositions of the collected aerosols. Throughout the fire, the smoke reaching the sampler was strongly monodisperse with most of the aerosol mass in the optically active 0.56–1.15 μm in aerodynamic diameter size range. Fine organics comprised almost all of the mass in this optically active size range and the concentrations of the organics were high throughout the sampling period. However, unlike the fine organics, the potassium concentrations in the smoke decreased exponentially during the sampling period as the fire progressed from an active flaming to a smoldering behavior. The major findings from this field experiment are the dramatic differences in aerosol composition as a function of fire type (i.e. smoldering or active flaming) and that the largest emission of organics occurs during the smoldering phase, unaccompanied by the potassium emissions often used as a smoke tracer. These results agree with recent laboratory experiments.

Effects of Distorted Wave on Proton Elastic Scattering fromLight Nuclei at 200 MeV

The distorted wave is introduced into the relativistic impulseapproximation to generate the Dirac optical potentials for protonelastic scattering. Those potentials, produced by folding the targetground state wavefunction with the free nucleon-nucleon interactions,are used to reevaluate scattering observables, such as differentialcross section, analysing power and spin rotation function, for protonelastic scattering from 12C and 16O at Elab = 200 MeV, respectively. The inclusion of the distorted wave in theoriginal relativistic impulse approximation has brought out betterresults of the observables, especially at small scattering angles.

Proton Elastic Scattering from 14Be and HaloEffects

The elastic scattering of p -14Be system atElab = 200 MeV is evaluated within the relativisticimpulse approximation. We discuss the effects of thehalo neutrons on the three observables of the elastic scatteringsystem, such as differential cross sectiondσ/dΩ, analyzing power Ay andspin rotation Q. The results of the three observables of theelastic scattering of p -14Be system are compared with thoseof p -12C and p -16O systems at the same energyas Elab = 200 MeV. We have found that in the small angularregion the Ay and Q, as well as dσ/dΩ, are quitesensitive to the nucleon density distributions on the surface ofthe target nucleus and offer some unique behaviors of halo nuclei.

Aerosol composition and source apportionment in the Mexico City Metropolitan Area with PIXE/PESA/STIM and multivariate analysis

Abstract. Aerosols play an important role in the atmosphere but are poorly characterized, particularly in urban areas like the Mexico City Metropolitan Area (MCMA). The chemical composition of urban particles must be known to assess their effects on the environment, and specific particulate emissions sources should be identified to establish effective pollution control standards. For these reasons, samples of particulate matter ≤2.5 μm (PM2.5) were collected during the MCMA-2003 Field Campaign for elemental and multivariate analyses. Proton-Induced X-ray Emission (PIXE), Proton-Elastic Scattering Analysis (PESA) and Scanning Transmission Ion Microscopy (STIM) measurements were done to determine concentrations of 19 elements from Na to Pb, hydrogen, and total mass, respectively. The most abundant elements from PIXE analysis were S, Si, K, Fe, Ca, and Al, while the major emissions sources associated with these elements were industry, wind-blown soil, and biomass burning. Wind trajectories suggest that metals associated with industrial emissions came from northern areas of the city whereas soil aerosols came from the southwest and increased in concentration during dry conditions. Elemental markers for fuel oil combustion, V and Ni, correlated with a large SO2 plume to suggest an anthropogenic, rather than volcanic, emissions source. By subtracting major components of soil and sulfates determined by PIXE analysis from STIM total mass measurements, we estimate that approximately 50% of non-volatile PM2.5 consisted of carbonaceous material.

Combinatorial ion synthesis and ion beam analyses of materials libraries on thermally grown SiO 2

We first report a method combining ion implantation and physical masking to generate material libraries of various ion-implanted samples. This approach offers rapid synthesis of samples with potential new compounds formed in the matrix, which may have specific luminescent properties. The depth-resolved cathodoluminescence (CL) measurements, accompanied with Rutherford backscattering spectrometry (RBS) and proton elastic scattering (PES) revealed some specific optical properties in the samples correlated with implanted ion distributions. These measurements are capable of nondestructively and rapidly characterizing the composition and the inhomogeneity of the combinatorial film libraries, which may determine their physical properties.

Proton Elastic Scattering and Neutron Distribution of Unstable Nuclei

Proton Elastic Scattering and Neutron Distribution of Unstable Nuclei

Cathodoluminescence and ion beam analysis of ion-implanted combinatorial materials libraries on thermally grown SiO2

A method combining ion implantation and physical masking technique has been used to generate material libraries of various ion-implanted samples. Ion species of C, Ga, N, Pb, Sn, Y have been sequentially implanted to an SiO2 film grown on a silicon wafer through combinatorial masks and consequently a library of 64 (26) samples is generated by 6 masking combinations. This approach offers rapid synthesis of samples with potential new compounds formed in the matrix, which may have specific luminescent properties. The depth-resolved cathodoluminescence (CL) measurements revealed some specific optical property in the samples correlated with implanted ion distributions. A marker-based technique is developed for the convenient location of sample site in the analysis of Rutherford backscattering spectrometry (RBS) and proton elastic scattering (PES), intended to characterize rapidly the ion implanted film libraries. These measurements demonstrate the power of nondestructively and rapidly characterizing composition and the inhomogeneity of the combinatorial film libraries, which may determine their physical properties.

Investigation of titanium nitride films deposited at room temperature by energetic cluster impact

Energetic cluster impact (ECI) deposition was applied to grow titanium nitride films on silicon (100) substrate at room temperature. Proton elastic scattering (PES), X-ray diffraction (XRD) and atomic force microscopy (AFM) were employed to characterize the composition, structure and morphology of TiN x films, respectively. The PES results reveal that the films are N-deficient and there exists a certain amount of oxygen impurity in the films. It is found from the XRD results that the structure of TiN x films is sensitive to experimental conditions such as nitrogen gas partial pressure, sputtering current and substrate bias voltage and that TiN x films are (220) preferred orientation within some range of experimental conditions. The AFM observation indicates that the films become more uniform and compact with increasing substrate bias voltage. The root mean square roughness also decreases with increasing bias voltage. Some interpretation for the above results are also given in this paper.

Air quality work at Guelph: GAViM and a traffic tunnel study

The Guelph Aerosol and Visibility Monitoring (GAViM) program presently runs three monitoring sites: two rural sites compatible with the IMPROVE protocol and one urban site mostly for special comparison studies. Fine aerosol is analyzed by the Laser Integrated Plate Method (LIPM), Proton Elastic Scattering Analysis (PESA), Proton Induced X-ray Emission (PIXE) and gravimetric analysis. Air quality data from the presently running sites and from two rural sites operated in the past are available through the WWW. The Guelph Scanning Proton Laboratory also participates in other aerosol programs: PIXE was employed to determine the composition of the ambient aerosol in a Vancouver traffic tunnel, to identify the main emission sources and to make estimates of vehicle emission factors. The PIXE facility was also modified for analysis of size-fractionated samples from the PIXE International Cascade Impactor (PCI) sampler. Significant improvement in detection limits for light elements due to the two-detector PIXE system used in Guelph, was justified particularly because of low air particulate loadings in case of PCI.