Proton Nucleus Elastic Scattering Data.
1993-08-18
Version 00 The Proton Nucleus Elastic Scattering Data file PNESD contains the numerical data and the related bibliography for the differential elastic cross sections, polarization and integral nonelastic cross sections for elastic proton-nucleus scattering.
Elastic proton-proton scattering at RHIC
Yip, K.
2011-09-03
Here we describe elastic proton+proton (p+p) scattering measurements at RHIC in p+p collisions with a special optics run of {beta}* {approx} 21 m at STAR, at the center-of-mass energy {radical}s = 200 GeV during the last week of the RHIC 2009 run. We present preliminary results of single and double spin asymmetries.
Intermediate energy proton-deuteron elastic scattering
NASA Technical Reports Server (NTRS)
Wilson, J. W.
1973-01-01
A fully symmetrized multiple scattering series is considered for the description of proton-deuteron elastic scattering. An off-shell continuation of the experimentally known twobody amplitudes that retains the exchange symmeteries required for the calculation is presented. The one boson exchange terms of the two body amplitudes are evaluated exactly in this off-shell prescription. The first two terms of the multiple scattering series are calculated explicitly whereas multiple scattering effects are obtained as minimum variance estimates from the 146-MeV data of Postma and Wilson. The multiple scattering corrections indeed consist of low order partial waves as suggested by Sloan based on model studies with separable interactions. The Hamada-Johnston wave function is shown consistent with the data for internucleon distances greater than about 0.84 fm.
Differential Cross Sections for Proton-Proton Elastic Scattering
NASA Technical Reports Server (NTRS)
Norman, Ryan B.; Dick, Frank; Norbury, John W.; Blattnig, Steve R.
2009-01-01
Proton-proton elastic scattering is investigated within the framework of the one pion exchange model in an attempt to model nucleon-nucleon interactions spanning the large range of energies important to cosmic ray shielding. A quantum field theoretic calculation is used to compute both differential and total cross sections. A scalar theory is then presented and compared to the one pion exchange model. The theoretical cross sections are compared to proton-proton scattering data to determine the validity of the models.
Two-photon exchange and elastic electron-proton scattering
Peter Blunden; Wally Melnitchouk; John Tjon
2003-06-01
Two-photon exchange contributions to elastic electron-proton scattering cross sections are evaluated in a simple hadronic model including the finite size of the proton. The corrections are found to be small, but with a strong angular dependence at fixed Q{sup 2}. This is significant for the Rosenbluth technique for determining the ratio of electric and magnetic form factors of the proton, and partly reconciles the apparent discrepancy with the results of the polarization transfer technique.
Electron- and positron-proton elastic scattering in CLAS
L.B. Weinstein
2009-08-01
There is a significant disagreement between measurements of the proton electric form factor, G{sup p}{sub E}, using Rosenbluth separations and polarization transfer. This disagreement, if not explained, could pose a fundamental challenge to our understanding of electron scattering or proton structure. Two-photon exchange (TPE) processes, although not fully calculable, are the most likely explanation of this disagreement. We will definitively test this assertion by comparing the electron-proton and positron-proton elastic scattering cross section in the Jefferson Lab CLAS. We will make a mixed identical electron and positron tertiary beam by passing a 5.5 GeV primary electron beam through a radiator to make a photon beam and then passing the photon beam through a converter to make electron-positron pairs. Measuring the elastic cross sections simultaneously using identical lepton beams should significantly reduce systematic uncertainties.
Elastic Lambda-proton Scattering in CLAS
NASA Astrophysics Data System (ADS)
Price, John; CLAS Collaboration
2016-03-01
The Λ-proton reaction is important to our understanding of the structure of the proton and the nature of the strong nuclear force. Most previous measurements used bubble chambers with kaon beams to produce the Λ ``beam'', which then interacted with a second proton inside the chamber. The Λ can also be produced in the process γp -->K+ Λ , which has been studied at Jefferson Lab by the CLAS Collaboration. The long decay length of the Λ allows it to interact with a second proton in the target, leading to the process Λp --> Λp . The large acceptance of CLAS makes it a good choice for the study of this final state. A data-mining project was initiated with the CLAS g12 run, which used a tagged photon beam with 3.6
Parity Violation in Forward Angle Elastic Electron Proton Scattering
Krishna Kumar
1999-07-01
HAPPEX is a new experiment to probe the strange structure of the nucleon with parity violating electron scattering. We describe the physics motivation, provide an experimental overview and report on the results from the first data run. The asymmetry for the elastic scattering of 3.3 GeV electrons off target protons at a scattering angle of 12.5 degrees was measured to a precision of 15% of itself. The contribution from strange quark form factors was found to be zero within the experimental and theoretical uncertainties.
Deuteron-proton elastic scattering at intermediate energies
Ladygina, N. B.
2008-12-15
The deuteron-proton elastic scattering has been studied in the multiple-scattering expansion formalism. Primary attention has been given to such relativistic problems as a deuteron wave function in a moving frame and transformation of spin states due to Wigner rotation. Parametrization of the nucleon-nucleon t matrix has been used to take the off-energy-shell effects into account. The vector, A{sub y}, and tensor, A{sub yy}, analyzing powers of the deuteron have been calculated at two deuteron kinetic energies: 395 and 1200 MeV. The obtained results are compared with the experimental data.
Vector analyzing power in elastic electron-proton scattering
Diaconescu, L.; Ramsey-Musolf, M.J.
2004-11-01
We compute the vector analyzing power (VAP) for the elastic scattering of transversely polarized electrons from protons at low energies using an effective theory of electrons, protons, and photons. We study all contributions through second order in E/M, where E and M are the electron energy and nucleon mass, respectively. The leading-order VAP arises from the imaginary part of the interference of one- and two-photon exchange amplitudes. Subleading contributions are generated by the nucleon magnetic moment and charge radius as well as recoil corrections to the leading-order amplitude. Working to O(E/M){sup 2}, we obtain a prediction for A{sub n} that is free of unknown parameters and that agrees with the recent measurement of the VAP in backward angle ep scattering.
Vector analyzing power in elastic electron-proton scattering
NASA Astrophysics Data System (ADS)
Diaconescu, L.; Ramsey-Musolf, M. J.
2004-11-01
We compute the vector analyzing power (VAP) for the elastic scattering of transversely polarized electrons from protons at low energies using an effective theory of electrons, protons, and photons. We study all contributions through second order in E/M , where E and M are the electron energy and nucleon mass, respectively. The leading-order VAP arises from the imaginary part of the interference of one- and two-photon exchange amplitudes. Subleading contributions are generated by the nucleon magnetic moment and charge radius as well as recoil corrections to the leading-order amplitude. Working to O (E/M)2 , we obtain a prediction for An that is free of unknown parameters and that agrees with the recent measurement of the VAP in backward angle ep scattering.
Neutrino-proton and anti-neutrino-proton elastic scattering
Fuess, Stuart Charles
1981-01-01
An experiment performed at the Brookhaven National Laboratory Alternating Gradient Synchrotron observed the elastic scattering of neutrinos and anti-neutrinos from a nuclear target. The neutral current anti-neutrino to neutral current neutrino ratio is: sigma(anti ..nu..p ..-->.. anti ..nu..p)/sigma(..nu..p ..-->.. ..nu..p) = 0.45 +- 0.18 for 0.33 less than or equal to Q/sup 2/ less than or equal to 1.0 (GeV/c)/sup 2/, where Q/sup 2/ is the square of the momentum transfer to the nucleon. The neutrino neutral current to charged current ratio is: sigma(..nu..p ..-->.. ..nu..p)/sigma(..nu..n ..-->.. ..mu../sup -/p) = 0.13 +- 0.04 for 0.25 less than or equal to Q/sup 2/ less than or equal to 1.0 (GeV/c)/sup 2/. The ratios are consistent with a value of the Weinberg angle of sin/sup 2/theta/sub w/ = 0.26 +- 0.08.
Measurement of elastic muon-neutrino scattering off protons
NASA Astrophysics Data System (ADS)
Faissner, H.; Frenzel, E.; Hansl, T.; Hoffmann, D.; Radermacher, E.; Reithler, H.; Samm, U.; de Witt, H.; Baldo-Ceolin, M.; Bobisut, F.; Huzita, H.; Loreti, M.; Puglierin, G.
1980-02-01
Single recoil protons have been detected in a multiplate Al spark chamber exposed to the 2-GeV wide-band neutrino beam from the CERN proton synchrotron. Neutron-induced protons were suppressed by suitable geometrical and kinematical cuts. After correction for remaining neutron background (110+/-15 events) and single-pion contribution (45+/-6 events), the final sample contains 62+/-19 genuine neutrino-induced single protons. This yields an effective ratio of neutral-current (NC) to charged-current (CC) events of RN=(15+/-5)%, in the range 0.2<-q2<1.0 (GeV/c)2. This number is due to a mixture of elastic neutrino scatterings off protons and neutrons. From the probability fnp for a recoil neutron to give an accepted proton, one derives a model-independent combination of the NC/CC ratios Rp+fnpRn, with fnp=0.31+/-0.04. This favors axial-vector-isovector-dominant NC coupling constants and is consistent with the Weinberg-Salam model with 2θW=0.29+0.21-0.11. In terms of this model, this corresponds to Rp=(10+/-3)% and Rn=(15+3-5)%.
The recoil proton polarization in. pi. p elastic scattering
Seftor, C.J.
1988-09-01
The polarization of the recoil proton for ..pi../sup +/p and ..pi../sup -/p elastic scattering has been measured for various angles at 547 MeV/c and 625 MeV/c by a collaboration involving The George Washington University; the University of California, Los Angeles; and Abilene Christian University. The experiment was performed at the P/sup 3/ East experimental area of the Los Alamos Meson Physics Facility. Beam intensities varied from 0.4 to 1.0 x 10/sup 7/ ..pi../sup -/'s/sec and from 3.0 to 10.0 x 10/sup 7/ ..pi../sup +/'s/sec. The beam spot size at the target was 1 cm in the horizontal direction by 2.5 cm in the vertical direction. A liquid-hydrogen target was used in a flask 5.7 cm in diameter and 10 cm high. The scattered pion and recoil proton were detected in coincidence using the Large Acceptance Spectrometer (LAS) to detect and momentum analyze the pions and the JANUS recoil proton polarimeter to detect and measure the polarization of the protons. Results from this experiment are compared with previous measurements of the polarization, with analyzing power data previously taken by this group, and to partial-wave analysis predictions. 12 refs., 53 figs., 18 tabs.
Study of elastic proton-proton scattering with the STAR detector at RHIC
NASA Astrophysics Data System (ADS)
Sikora, Rafal
2015-09-01
The STAR detector at the Relativistic Heavy Ion Collider (RHIC) is equipped with system of dedicated Silicon Strip Detectors housed inside Roman Pot vessels, allowing to detect protons scattered at small angles. Data from polarized proton-proton collisions at center-of-mass system (c.m.s.) energy √s = 200 GeV collected with special settings of RHIC magnet lattice (β * = 22 m) allow to study proton-proton elastic scattering at very low values of squared four-momentum transfer (Mandelstam t), 0:003 <= -t <= 0:035 GeV2=c2. Results of analysis of systematic effects and large statistics of collected data sample reveal possibility of measurement of the Nuclear Slope Parameter with precision not yet achieved at this c.m.s. energy.
Small angle elastic scattering of protons off of spinless nuclei
Ling, A.G.
1988-07-01
Elastic differential cross sections and analyzing powers for 800 MeV protons incident on /sup 12/C, /sup 40/Ca, and /sup 208/Pb in the momentum transfer range 20 MeV/c < q < 130 MeV/c have been measured. The data was taken with the High Resolution Spectrometer (HRS) at the Los Alamos Meson Physics Facility. Special delay-line drift chambers with dead regions for the beam to pass through them were used to obtain the data. Through the interference of the Coulomb and nuclear contributions to the differential cross section in the small angle region, the ratio of the real to imaginary part of the forward nuclear amplitude ..cap alpha../sub n/(0) = Ref/sub n/(0)/Imf/sub n/(0) is extracted. The importance of knowing this quantity at lower energies in order to study the differences between relativistic and non-relativistic scattering theories is discussed. 130 refs., 60 figs., 12 tabs.
Proton form factors and two-photon exchange in elastic electron-proton scattering
Nikolenko, D. M.; Arrington, J.; Barkov, L. M.; Vries, H. de; Gauzshtein, V. V.; Golovin, R. A.; Gramolin, A. V.; Dmitriev, V. F.; Zhilich, V. N.; Zevakov, S. A.; Kaminsky, V. V.; Lazarenko, B. A.; Mishnev, S. I.; Muchnoi, N. Yu.; Neufeld, V. V.; Rachek, I. A.; Sadykov, R. Sh.; Stibunov, V. N.; Toporkov, D. K.; Holt, R. J.; and others
2015-05-15
Proton electromagnetic form factors are among the most important sources of information about the internal structure of the proton. Two different methods for measuring these form factors, the method proposed by Rosenbluth and the polarization-transfer method, yield contradictory results. It is assumed that this contradiction can be removed upon taking into account the hard part of the contribution of two-photon exchange to the cross section for elastic electron-proton scattering. This contribution can measured experimentally via a precision comparison of the cross sections for the elastic scattering of positrons and electrons on protons. Such a measurement, performed at the VEPP-3 storage ring in Novosibirsk at the beam energies of 1.6 and 1.0 GeV for positron (electron) scattering angles in the ranges of θ{sub e} = 15°–25° and 55°–75° in the first case and in the range of θ{sub e} = 65°–105° in the second case is described in the present article. Preliminary results of this experiment and their comparison with theoretical predictions are described.
Studying the proton 'radius' puzzle with μp elastic scattering
Gilman, R.
2013-11-07
The disagreement between the proton radius determined from muonic hydrogen and from electronic measurements is called the proton radius puzzle. The resolution of the puzzle remains unclear and appears to require new experimental results. An experiment to measure muon-proton elastic scattering is presented here.
Measuring the Weak Charge of the Proton via Elastic Electron-Proton Scattering
Jones, Donald C.
2015-10-01
The Qweak experiment which ran in Hall C at Jefferson Lab in Newport News, VA, and completed data taking in May 2012, measured the weak charge of the proton Q^{p}_{W} via elastic electron-proton scattering. Longitudinally polarized electrons were scattered from an unpolarized liquid hydrogen target. The helicity of the electron beam was flipped at approximately 1 kHz between left and right spin states. The Standard Model predicts a small parity-violating asymmetry of scattering rates between right and left helicity states due to the weak interaction. An initial result using 4% of the data was published in October 2013 [1] with a measured parity-violating asymmetry of -279 ± 35(stat) ± 31 (syst) ppb. This asymmetry, along with other data from parity-violating electron scattering experiments, provided the world's first determination of the weak charge of the proton. The weak charge of the proton was found to be ^{p}_{W} = 0.064 ± 0.012, in good agreement with the Standard Model prediction of ^{p}_{W}(SM) = 0.0708 ± 0.0003[2].
Spin observables in neutron-proton elastic scattering
Ahmidouch, A.; Arnold, J.; van den Brandt, B.; Daum, M.; Demierre, P.; Drevenak, R.; Finger, M. |; Finger, M. Jr.; Franz, J.; Goujon, N.; Hautle, P.; Janout, Z. Jr.; Hajdas, W.; Heer, E.; Hess, R.; Koger, R.; Konter, J.A.; Lacker, H.; Lechanoine-LeLuc, C.; Lehar, F.; Mango, S.; Mascarini, C.; Rapin, D.; Roessle, E.; Schmelzbach, P.A.; Schmitt, H.; Sereni, P.; Slunecka, M.
1995-07-15
We describe here two experiments presently running at PSI using the NA2 polarized neutron beam. They are devoted to the measurement of 2- and 3-spin observables in {ital np} elastic scattering for kinetic energies from 230 to 590 MeV with a center of mass angular range from 60 to 180 degrees. The goal is to determine the five {ital NN} scattering amplitudes for isospin 0 in a model independent way. Preliminary results for {ital K}{sub {ital OSKO}} and {ital K}{sub {ital OSSO}} spin-transfers are presented.
TWO-PHOTON EXCHANGE IN ELECTRON-PROTON ELASTIC SCATTERING: THEORY UPDATE
Andrei Afanasev
2007-05-21
Recent theoretical developments in the studies of two-photon exchange effects in elastic electron-proton scattering are reviewed. Two-photon exchange mechanism is considered a likely source of discrepancy between polarized and unpolarized experimental measurements of the proton electric form factor at momentum transfers of several GeV$^2$. This mechanism predicts measurable effects that are currently studied experimentally.
Two-photon exchange corrections in elastic lepton-proton scattering at small momentum transfer
NASA Astrophysics Data System (ADS)
Tomalak, Oleksandr; Vanderhaeghen, Marc
2016-03-01
In recent years, elastic electron-proton scattering experiments, with and without polarized protons, gave strikingly different results for the electric over magnetic proton form factor ratio. A mysterious discrepancy (``the proton radius puzzle'') has been observed in the measurement of the proton charge radius in muon spectroscopy experiments versus electron spectroscopy and electron scattering. Two-photon exchange (TPE) contributions are the largest source of the hadronic uncertainty in these experiments. We compare the existing models of the elastic contribution to TPE correction in lepton-proton scattering. A subtracted dispersion relation formalism for the TPE in electron-proton scattering has been developed and tested. Its relative effect on cross section is in the 1 - 2 % range for a low value of the momentum transfer. An alternative dispersive evaluation of the TPE correction to the hydrogen hyperfine splitting was found and applied. For the inelastic TPE contribution, the low momentum transfer expansion was studied. In addition with the elastic TPE it describes the experimental TPE fit to electron data quite well. For a forthcoming muon-proton scattering experiment (MUSE) the resulting TPE was found to be in the 0 . 5 - 1 % range, which is the planned accuracy goal.
A measurement of two-photon exchange in unpolarized elastic electron-proton scattering
NASA Astrophysics Data System (ADS)
Yurov, Mikhail
2016-03-01
Jefferson Lab experiment E05-017 was designed to study 2-photon exchange contributions to elastic electron-proton scattering over a wide kinematic range. By detecting the scattered proton instead of the electron these measurements will be very sensitive to the ɛ dependence of the cross section and consequently the ratio GE/GM. The goals of the experiment, the experimental technique and the kinematic range will be presented. The analysis sequence and results of the early steps will be outlined.
Pion-proton backward elastic scattering between 30 and 90 GeV/c
Baker, W.F.; Eartly, D.P.; Kalbach, R.M.; Klinger, J.S.; Lennox, A.J.; Polakos, P.A.; Pifer, A.E.; Rubinstein, R.
1982-11-01
Backward elastic scattering of ..pi..+- on protons has been measured for incident pion momenta between 30 and 90 GeV/c and 0<-u <0.5 (GeV/c)/sup 2/. The u-dependence of the cross sections is similar to that observed at lower momenta, and Regge models give acceptable fits to the data.
A recoil detector for the measurement of antiproton-proton elastic scattering at angles close to 90°
NASA Astrophysics Data System (ADS)
Hu, Q.; Bechstedt, U.; Gillitzer, A.; Grzonka, D.; Khoukaz, A.; Klehr, F.; Lehrach, A.; Prasuhn, D.; Ritman, J.; Sefzick, T.; Stockmanns, T.; Täschner, A.; Wuestner, P.; Xu, H.
2014-10-01
The design and construction of a recoil detector for the measurement of recoil protons of antiproton-proton elastic scattering at scattering angles close to are described. The performance of the recoil detector has been tested in the laboratory with radioactive sources and at COSY with proton beams by measuring proton-proton elastic scattering. The results of laboratory tests and commissioning with beam are presented. Excellent energy resolution and proper working performance of the recoil detector validate the conceptual design of the KOALA experiment at HESR to provide the cross section data needed to achieve a precise luminosity determination at the PANDA experiment.
A predictive theory for elastic scattering and recoil of protons from ^{4}He
Hupin, Guillaume; Quaglioni, Sofia; Navratil, Petr
2014-12-08
Low-energy cross sections for elastic scattering and recoil of protons from ^{4}He nuclei (also known as α particles) are calculated directly by solving the Schrodinger equation for five nucleons interacting through accurate two- and three-nucleon forces derived within the framework of chiral effective field theory. Precise knowledge of these processes at various proton backscattering/recoil angles and energies is needed for the ion-beam analysis of numerous materials, from the surface layers of solids, to thin films, to fusion-reactor materials. Indeed, the same elastic scattering process, in two different kinematic configurations, can be used to probe the concentrations and depth profiles of either hydrogen or helium. Furthermore, we compare our results to available experimental data and show that direct calculations with modern nuclear potentials can help to resolve remaining inconsistencies among data sets and can be used to predict these cross sections when measurements are not available.
A predictive theory for elastic scattering and recoil of protons from 4He
Hupin, Guillaume; Quaglioni, Sofia; Navratil, Petr
2014-12-08
Low-energy cross sections for elastic scattering and recoil of protons from 4He nuclei (also known as α particles) are calculated directly by solving the Schrodinger equation for five nucleons interacting through accurate two- and three-nucleon forces derived within the framework of chiral effective field theory. Precise knowledge of these processes at various proton backscattering/recoil angles and energies is needed for the ion-beam analysis of numerous materials, from the surface layers of solids, to thin films, to fusion-reactor materials. Indeed, the same elastic scattering process, in two different kinematic configurations, can be used to probe the concentrations and depth profiles ofmore » either hydrogen or helium. Furthermore, we compare our results to available experimental data and show that direct calculations with modern nuclear potentials can help to resolve remaining inconsistencies among data sets and can be used to predict these cross sections when measurements are not available.« less
Elastic proton scattering on tritium below the n-{sup 3}He threshold
Lazauskas, Rimantas
2009-05-15
Elastic proton scattering on the {sup 3}H nucleus is studied between p-{sup 3}H and n-{sup 3}He thresholds, in the energy region where the first excited state of the {alpha} particle is embedded in the continuum. Faddeev-Yakubovski equations are solved in configuration space by fully considering effects from isospin breaking and rigorously treating the Coulomb interaction. Different realistic nuclear Hamiltonians are tested, elucidating open problems in the description of the nuclear interaction.
High energy proton-proton elastic scattering at the Large Hadron Collider and nucleon structure
NASA Astrophysics Data System (ADS)
Luddy, Richard Joseph
To gain insight into the structure of the nucleon, we pursue the development of the phenomenological model of Islam et al. (IIFS model) for high energy elastic pp and p¯p scattering. We determine the energy dependence of the parameters of the IIFS model using the available elastic differential cross section data from SPS Collider and Tevatron and the known asymptotic behavior of sigmatot (s) and rho(s) from dispersion relation calculations and more recent analyses of Cudell et al. (COMPETE Collaboration). Next, we incorporate a high energy elastic valence quark-quark scattering amplitude into the model based on BFKL pomeron to describe small impact parameter (large | t|) pp collisions. Finally, we predict the pp elastic differential cross section at the unprecedented c.m. energy of s = 14.0 TeV at the Large Hadron Collider (LHC). This prediction assumes crucial significance---because of an approved experiment at LHC: TOTal and Elastic Measurement (TOTEM). The TOTEM group plans to measure pp elastic dsigma/dt at 14.0 TeV all the way from momentum transfer |t| = 0 to |t| ≃ 10 GeV 2. Their measurement will stringently test not only the diffraction and o-exchange descriptions of the original IIFS model, but also the additional valence quark-quark scattering contribution that we find to be dominant for large |t|. Successful quantitative verification of the predicted dsigma/dt will mean that our picture of the nucleon with an outer cloud of qq¯ condensed ground state, an inner core of topological baryonic charge, and a still smaller core of massless valence quarks provides a realistic description of nucleon structure.
Elastic Proton Scattering of Medium Mass Nuclei from Coupled-Cluster Theory
Hagen, G.; MichelN.,
2012-01-01
Using coupled-cluster theory and interactions from chiral effective field theory, we compute overlap functions for transfer and scattering of low-energy protons on the target nucleus 40Ca. Effects of three-nucleon forces are included phenomenologically as in-medium two-nucleon interactions. Using known asymptotic forms for one-nucleon overlap functions we derive a simple and intuitive way of computing scattering observables such as elastic scattering phase shifts and cross sections. As a first application and proof of principle, we compute phase shifts and differential interaction cross sections at energies of 9.6 and 12.44 MeV and compare with experimental data. Our computed diffraction minima are in fair agreement with experimental results, while we tend to overestimate the cross sections at large scattering angles.
Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering
David Armstrong; Francois Arvieux; Razmik Asaturyan; Todd Averett; Stephanie Bailey; Guillaume Batigne; Douglas Beck; Elizabeth Beise; Jay Benesch; Louis Bimbot; James Birchall; Angela Biselli; Peter Bosted; Elodie Boukobza; Herbert Breuer; Roger Carlini; Robert Carr; Nicholas Chant; Yu-Chiu Chao; Swapan Chattopadhyay; Russell Clark; Silviu Covrig; Anthony Cowley; Daniel Dale; Charles Davis; Willie Falk; John Finn; Tony Forest; Gregg Franklin; Christophe Furget; David Gaskell; Joseph Grames; Keith Griffioen; Klaus Grimm; Benoit Guillon; Hayko Guler; Lars Hannelius; Richard HASTY; Alice Hawthorne Allen; Tanja Horn; Kathleen Johnston; Mark Jones; Peter Kammel; Reza Kazimi; Paul King; Ameya Kolarkar; Elie Korkmaz; Wolfgang Korsch; Serge Kox; Joachim Kuhn; Jeff Lachniet; Lawrence Lee; Jason Lenoble; Eric Liatard; Jianglai Liu; Berenice Loupias; Allison Lung; Dominique Marchand; Jeffery Martin; Kenneth McFarlane; David McKee; Robert McKeown; Fernand Merchez; Hamlet Mkrtchyan; Bryan Moffit; M. Morlet; Itaru Nakagawa; Kazutaka Nakahara; Retief Neveling; Silvia Niccolai; S. Ong; Shelley Page; Vassilios Papavassiliou; Stephen Pate; Sarah Phillips; Mark Pitt; Benard Poelker; Tracy Porcelli; Gilles Quemener; Brian Quinn; William Ramsay; Aamer Rauf; Jean-Sebastien Real; Julie Roche; Philip Roos; Gary Rutledge; Jeffery Secrest; Neven Simicevic; Gregory Smith; Damon Spayde; Samuel Stepanyan; Marcy Stutzman; Vince Sulkosky; Vincent Sulkosky; Vince Sulkosky; Vincent Sulkosky; Vardan Tadevosyan; Raphael Tieulent; Jacques Van de Wiele; Willem van Oers; Eric Voutier; William Vulcan; Glen Warren; Steven Wells; Steven Williamson; Stephen Wood; Chen Yan; Junho Yun; Valdis Zeps
2007-08-01
We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 values of 0.15 and 0.25 (GeV/c)^2 with results of A_n = -4.06 +- 0.99(stat) +- 0.63(syst) and A_n = -4.82 +- 1.87(stat) +- 0.98(syst) ppm. These results are inconsistent with calculations solely using the elastic nucleon intermediate state, and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A_n provides a direct probe of the imaginary component of the two-photon exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.
Relativistic impulse approximation analysis of elastic proton scattering from He isotopes
NASA Astrophysics Data System (ADS)
Kaki, Kaori
2014-01-01
Recent relativistic mean field (RMF) calculations have provided nuclear distributions of some isotopes whose mass numbers are much larger than atomic numbers. For helium isotopes, the RMF calculation seems to be inappropriate because of the small mass numbers; however, applicable results are obtained for 6,8He nuclei. The author calculates observables of proton elastic scattering from the helium isotopes and discusses relations between observables and nuclear distributions of the isotopes by comparison of the calculated results with experimental data. The calculations are based on relativistic impulse approximation (RIA) at incident proton energy: 71 MeV for 4,6,8He, 300 and 500 MeV for 4He, and 0.7 GeV for 6He. Scattering observables are predicted for 6,8He at 200 MeV.
Fast Proton Hopping Detection in Ice Ih by Quasi-Elastic Neutron Scattering
Presiado, Itay; Lal, Jyotsana; Mamontov, Eugene; Kolesnikov, Alexander I; Huppert, Dan I
2011-01-01
Quasi-elastic neutron scattering was employed on samples of HCl-doped polycrystalline ice I{sub h}. The analysis of the scattering signal provides the excess proton hopping time, {tau}{sub hop}, in the temperature range of 140-195 K. The hopping time strongly depends on the temperature of the sample, and the activation energy of a hopping step is 17 kJ/mol. The values of {tau}{sub hop} of the current experiment are in good agreement with calculated values derived from previous photochemical experiments,(1) in which we found that the proton hopping time at T > 242 K is on the order of 200 fs, roughly 10 times shorter than in liquid water at room temperature.
Fast proton hopping detection in ice I{sub h} by quasi-elastic neutron scattering.
Presiado, I.; Lal, J.; Mamontov, E.; Kolesnikov, A. I.; Huppert, D.
2011-01-01
Quasi-elastic neutron scattering was employed on samples of HCl-doped polycrystalline ice I{sub h}. The analysis of the scattering signal provides the excess proton hopping time, {tau}{sub hop}, in the temperature range of 140-195 K. The hopping time strongly depends on the temperature of the sample, and the activation energy of a hopping step is 17 kJ/mol. The values of {tau}{sub hop} of the current experiment are in good agreement with calculated values derived from previous photochemical experiments, in which we found that the proton hopping time at T > 242 K is on the order of 200 fs, roughly 10 times shorter than in liquid water at room temperature.
Phenomenological optical potential analysis of proton-carbon elastic scattering at 200 MeV
NASA Technical Reports Server (NTRS)
Bidasaria, H. B.; Townsend, L. W.
1982-01-01
Differential cross sections for 200 MeV protons elastically scattered from C-12 were analyzed utilizing a local, complex, spin-dependent optical potential with a harmonic well radial dependence. Analyses were performed using the WKB and eikonal approximations. For the latter, first-order corrections to he phase shifts were incorporated to account for the spin-orbit contribution. Large disagreement between theory and experiment was observed when the usual Thomas form for the spin-orbit potential was utilized. Substantial improvement was obtained by allowing the parameters in the central and spin-orbit potential terms to vary independently.
Alkhazov, G. D.; Vorobyov, A. A.; Dobrovolsky, A. V. Inglessi, A. G.; Korolev, G. A.; Khanzadeev, A. V.
2015-05-15
In order to study the spatial structure of exotic nuclei, it was proposed at the Petersburg Nuclear Physics Institute (PNPI) to measure the differential cross section for small-angle proton elastic scattering in inverse kinematics. Several experiments in beams of 0.7-GeV/nucleon exotic nuclei were performed at the heavy-ion accelerator facility of GSI (Gesellschaft für Schwerionenforschung, Darmstadt, Germany) by using the IKAR ionization spectrometer developed at PNPI. The IKAR ionization chamber filled with hydrogen at a pressure of 10 bar served simultaneously as a target and as a recoil-proton detector, which measured the recoil-proton energy. The beam-particle scattering angle was also measured. The results obtained for the cross sections in question were analyzed on the basis of the Glauber-Sitenko theory using phenomenological nuclear-density distributions with two free parameters. Nuclear-matter distributions and root-mean-square radii were found for the nuclei under investigation. The size of the halo in the {sup 6}He, {sup 8}He, {sup 11}Li, and {sup 14}Be nuclei was determined among other things. Information about neutron distributions in nuclei was deduced by combining the data obtained here with the known values of the radii of proton distributions. A sizable neutron skin was revealed in the {sup 8}Li, {sup 9}Li, and {sup 12}Be nuclei.
NASA Astrophysics Data System (ADS)
Alkhazov, G. D.; Vorobyov, A. A.; Dobrovolsky, A. V.; Inglessi, A. G.; Korolev, G. A.; Khanzadeev, A. V.
2015-05-01
In order to study the spatial structure of exotic nuclei, it was proposed at the Petersburg Nuclear Physics Institute (PNPI) to measure the differential cross section for small-angle proton elastic scattering in inverse kinematics. Several experiments in beams of 0.7-GeV/nucleon exotic nuclei were performed at the heavy-ion accelerator facility of GSI (Gesellschaft für Schwerionenforschung, Darmstadt, Germany) by using the IKAR ionization spectrometer developed at PNPI. The IKAR ionization chamber filled with hydrogen at a pressure of 10 bar served simultaneously as a target and as a recoil-proton detector, which measured the recoil-proton energy. The beam-particle scattering angle was also measured. The results obtained for the cross sections in question were analyzed on the basis of the Glauber-Sitenko theory using phenomenological nuclear-density distributions with two free parameters. Nuclear-matter distributions and root-mean-square radii were found for the nuclei under investigation. The size of the halo in the 6He, 8He, 11Li, and 14Be nuclei was determined among other things. Information about neutron distributions in nuclei was deduced by combining the data obtained here with the known values of the radii of proton distributions. A sizable neutron skin was revealed in the 8Li, 9Li, and 12Be nuclei.
Mchedlishvili, D.; Chiladze, D.; Dymov, S.; Bagdasarian, Z.; Barsov, S.; Gebel, R.; Gou, B.; Hartmann, M.; Kacharava, A.; Keshelashvili, I.; et al
2016-02-03
The differential cross section for proton-proton elastic scattering has been measured at a beam kinetic energy of 1.0 GeV and in 200 MeV steps from 1.6 to 2.8 GeV for centre-of-mass angles in the range from 12°-16° to 25°-30°, depending on the energy. A precision in the overall normalisation of typically 3% was achieved by studying the energy losses of the circulating beam of the COSY storage ring as it passed repeatedly through the windowless hydrogen target of the ANKE magnetic spectrometer. It is shown that the data have a significant impact upon the results of a partial wave analysis.more » Furthermore, after extrapolating the differential cross sections to the forward direction, the results are broadly compatible with the predictions of forward dispersion relations.« less
Proton-Nucleus Elastic Cross Sections Using Two-Body In-Medium Scattering Amplitudes
NASA Technical Reports Server (NTRS)
Tripathi, R. K.; Wilson, John W.; Cucinotta, Francis A.
2001-01-01
Recently, a method was developed of extracting nucleon-nucleon (NN) cross sections in the medium directly from experiment. The in-medium NN cross sections form the basic ingredients of several heavy-ion scattering approaches including the coupled-channel approach developed at the Langley Research Center. The ratio of the real to the imaginary part of the two-body scattering amplitude in the medium was investigated. These ratios are used in combination with the in-medium NN cross sections to calculate elastic proton-nucleus cross sections. The agreement is excellent with the available experimental data. These cross sections are needed for the radiation risk assessment of space missions.
Spin observables in quasi-elastic proton-nucleus scattering near 1 GeV
Smith, R.D.; Wallace, S.J.
1985-11-01
The spin dependence of quasi-elastic proton-nucleus scattering is studied using Glauber's eikonal multiple scattering theory, which is extended to include multiple knockout collisions as well as the full spin dependence of the NN amplitudes. Calculations of the cross section d/sup 2/sigma/d..cap omega.. dp and spin observables DNN, DLL, DSS, DSL, DLS, Ay are presented and compared to data for d/sup 2/sigma/d..cap omega.. dp and Ay from inclusive (p,p') experiments on /sup 12/C at T/sub lab/ = 800 MeV. The main feature seen is a drop in the spin observables in the kinematic region where two nucleon knockout dominates the cross section. As an initial study of the contribution of quasi-free ..delta.. production to the inclusive cross section, multiple scattering theory is used to normalize a plane-wave impulse approximation calculation of d/sup 2/sigma/d..cap omega.. dp for p+/sup 12/C..-->..p+..pi..+/sup 12/C(. .AE
The Intermediate Energy Elastic Scattering of Protons by α-CLUSTER 20Ne and 24Mg Nuclei
NASA Astrophysics Data System (ADS)
Berezhnoy, Yu. A.; Mikhailyuk, V. P.; Pilipenko, V. V.
The multiple diffraction scattering theory and the α-cluster model with dispersion have been applied for calculations of the observables for the elastic scattering of intermediate energy protons by 20Ne and 24Mg nuclei. The target nuclei are considered as composed of the core (16O nucleus) and additional α-clusters (one α-cluster for 20Ne nucleus and a dumb-bell α-cluster configuration for 24Mg nucleus). Taking into account the α-cluster configuration of the core, it was supposed that the additional α-cluster or center of mass of the dumb-bell are arranged with the most probability inside or outside of the core. The calculated observables for the elastic p-20Ne and p-24Mg scattering are in agreement with the existing experimental data. The influence of the deformed core contribution on the behavior of the calculated observables also is tested.
Spin-rotation parameter Q for elastic scattering of 800 MeV polarized protons from WO, UCa, and SYPb
Fergerson, R.W.
1985-10-01
The spin-rotation parameter Q was measured for WO, UCa, and SYPb using the 800 MeV proton beam produced at the Clinton P. Anderson Meson Physics Facility. The experiment was carried out using the High Resolution Spectrometer equipped with a focal-plane polarimeter to determine the scattered polarization components in all three directions. These data (when combined with previous cross section and analyzing power data) determine the amplitude describing the elastic scattering of protons from these spin-zero nuclei to within an overall phase. Q is shown to be more sensitive than either the cross section or analyzing power to differences between the nonrelativistic and relativistic scattering theories that describe the proton-nucleus reaction in terms of fundamental proton-nucleon input. The nonrelativistic predictions for Q generally lie below the data but consistently have the correct structure. The relativistic predictions for the UCa and SYPb Q data are quite good (better than the nonrelativistic predictions). The relativistic predictions for the WO Q data show much more structure than is evident in the data. 51 refs., 39 figs., 4 tabs.
NASA Astrophysics Data System (ADS)
Rachek, I. A.; Arrington, J.; Dmitriev, V. F.; Gauzshtein, V. V.; Gramolin, A. V.; Holt, R. J.; Kaminskiy, V. V.; Lazarenko, B. A.; Mishnev, S. I.; Muchnoi, N. Yu; Neufeld, V. V.; Nikolenko, D. M.; Sadykov, R. Sh; Shestakov, Yu V.; Stibunov, V. N.; Toporkov, D. K.; de Vries, H.; Zevakov, S. A.; Zhilich, V. N.
2015-11-01
A striking discrepancy between the results for the ratio of electric and magnetic form factors of the proton obtained by two approaches: the Rosenbluth extraction from the unpolarized cross section and the double-polarization measurements has led to a serious re-examination of the role played by two-photon exchange diagrams. The evaluation of such diagrams could not be done in model-independent way, which means an experimental verification is required. One of the direct ways to do this is to measure the ratio of positron-proton and electron-proton elastic scattering cross-sections for identical kinematics. Such a measurement has been performed at the VEPP-3 storage ring at Novosibirsk. There were two runs at beam energies of 1.6 and 1.0 GeV at several ranges of scattering angle. The measurements covered the transferred momentum Q2 up to 1.5 GeV2 and the virtual photon polarization parameter ɛ down to 0.2 . The VEPP-3 experimental approach is described and the results of the measurements are presented.
Li, Z. P.; Hillhouse, G. C.; Meng, J.
2008-07-15
We present the first study to examine the validity of the relativistic impulse approximation (RIA) for describing elastic proton-nucleus scattering at incident laboratory kinetic energies lower than 200 MeV. For simplicity we choose a {sup 208}Pb target, which is a spin-saturated spherical nucleus for which reliable nuclear structure models exist. Microscopic scalar and vector optical potentials are generated by folding invariant scalar and vector scattering nucleon-nucleon (NN) amplitudes, based on our recently developed relativistic meson-exchange model, with Lorentz scalar and vector densities resulting from the accurately calibrated PK1 relativistic mean field model of nuclear structure. It is seen that phenomenological Pauli blocking (PB) effects and density-dependent corrections to {sigma}N and {omega}N meson-nucleon coupling constants modify the RIA microscopic scalar and vector optical potentials so as to provide a consistent and quantitative description of all elastic scattering observables, namely, total reaction cross sections, differential cross sections, analyzing powers and spin rotation functions. In particular, the effect of PB becomes more significant at energies lower than 200 MeV, whereas phenomenological density-dependent corrections to the NN interaction also play an increasingly important role at energies lower than 100 MeV.
Elastic scattering in geometrical model
NASA Astrophysics Data System (ADS)
Plebaniak, Zbigniew; Wibig, Tadeusz
2016-10-01
The experimental data on proton-proton elastic and inelastic scattering emerging from the measurements at the Large Hadron Collider, calls for an efficient model to fit the data. We have examined the optical, geometrical picture and we have found the simplest, linear dependence of this model parameters on the logarithm of the interaction energy with the significant change of the respective slopes at one point corresponding to the energy of about 300 GeV. The logarithmic dependence observed at high energies allows one to extrapolate the proton-proton elastic, total (and inelastic) cross sections to ultra high energies seen in cosmic rays events which makes a solid justification of the extrapolation to very high energy domain of cosmic rays and could help us to interpret the data from an astrophysical and a high energy physics point of view.
Study of proton resonance structure in 27P via resonant elastic scattering of 26Si+p
NASA Astrophysics Data System (ADS)
Jung, H. S.; Lee, C. S.; Kwon, Y. K.; Moon, J. Y.; Lee, J. H.; Yun, C. C.; Kubono, S.; Yamaguchi, H.; Hashimoto, T.; Kahl, D.; Hayakawa, S.; Choi, Seonho; Kim, M. J.; Kim, Y. H.; Kim, Y. K.; Park, J. S.; Kim, E. J.; Moon, C.-B.; Teranishi, T.; Wakabayashi, Y.; Iwasa, N.; Yamada, T.; Togano, Y.; Kato, S.; Cherubini, S.; Rapisarda, G. G.
2012-11-01
A measurement of resonant elastic scattering of 26Si+p was performed with a thick target using a 26Si radioactive ion beam at the CRIB (CNS Radioactive Ion Beam separator) of the Center for Nuclear Study (CNS), the University of Tokyo. The excitation function of 27P was measured successfully with the inverse kinematics method through a covered the range of excitation energies from Ex ~ 2.3 to 3.8 MeV, providing information about the resonance structure of this nucleus. The properties of these resonances are important to better determine the production rates of 26Si(p,g)27P reaction, which is one of the astrophysically important nuclear reactions to understand the production of the 26Al. Some new resonant states have been investigated, and determined their resonance parameters, such as excitation energies, proton partial widths, and spin-parities by R-matrix calculation.
Konrad Aniol; David Armstrong; Todd Averett; Maud Baylac; Etienne Burtin; John Calarco; Gordon Cates; Christian Cavata; Zhengwei Chai; C. Chang; Jian-Ping Chen; Eugene Chudakov; Evaristo Cisbani; Marius Coman; Daniel Dale; Alexandre Deur; Pibero Djawotho; Martin Epstein; Stephanie Escoffier; Lars Ewell; Nicolas Falletto; John Finn; A. Fleck; Bernard Frois; Salvatore Frullani; Juncai Gao; Franco Garibaldi; Ashot Gasparian; G. M. Gerstner; Ronald Gilman; Oleksandr Glamazdin; Javier Gomez; Viktor Gorbenko; Jens-ole Hansen; F. Hersman; Douglas Higinbotham; Richard Holmes; Maurik Holtrop; Thomas Humensky; Sebastien Incerti; Mauro Iodice; Cornelis De Jager; Johann Jardillier; Xiaodong Jiang; Mark Jones; J. Jorda; Christophe Jutier; W. Kahl; James Kelly; Donghee Kim; M. -J. Kim; Minsuk Kim; Ioannis Kominis; Edgar Kooijman; Kevin Kramer; Krishna Kumar; Michael Kuss; John LeRose; Raffaele De Leo; M. Leuschner; David Lhuillier; Meihua Liang; Nilanga Liyanage; R. Lourie; Richard Madey; Sergey Malov; Demetrius Margaziotis; Frederic Marie; Pete Markowitz; Jacques Martino; Peter Mastromarino; Kathy McCormick; Justin McIntyre; Zein-Eddine Meziani; Robert Michaels; Brian Milbrath; Gerald Miller; Joseph Mitchell; Ludyvine Morand; Damien Neyret; Gerassimos Petratos; Roman Pomatsalyuk; John Price; David Prout; Thierry Pussieux; Gilles Quemener; Ronald Ransome; David Relyea; Yves Roblin; Julie Roche; Gary Rutledge; Paul Rutt; Marat Rvachev; Franck Sabatie; Arunava Saha; Paul Souder; Marcus Spradlin; Steffen Strauch; Riad Suleiman; Jeffrey Templon; T. Teresawa; James Thompson; Raphael Tieulent; Luminita Todor; Baris Tonguc; Paul Ulmer; Guido Urciuoli; Branislav Vlahovic; Krishni Wijesooriya; R. Wilson; Bogdan Wojtsekhowski; Rhett Woo; Wang Xu; Imran Younus; C. Zhang
2001-06-01
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The result is A = -15.05 +- 0.98(stat) {+-} 0.56(syst) ppm at the kinematic point theta{sub lab} = 12.3 degrees and Q{sup 2} = 0.477 (GeV/c){sup 2}. The measurement implies that the value for the strange form factor (G{sub E}{sup s} + 0.392 G{sub M}{sup s})/(G{sub M}{sup p} {mu}{sub p}) = 0.069 +- 0.056 +- 0.039, where the first error is experimental and the second arises from the uncertainties in electromagnetic form factors. This measurement is the first fixed-target parity violation experiment that used either a ''strained'' GaAs photocathode to produce highly polarized electrons or a Compton polarimeter to continuously monitor the electron beam polarization.
NASA Astrophysics Data System (ADS)
Dremin, I. M.
2013-01-01
Colliding high-energy hadrons either produce new particles or scatter elastically with their quantum numbers conserved and no other particles produced. We consider the latter case here. Although inelastic processes dominate at high energies, elastic scattering contributes considerably (18-25%) to the total cross section. Its share first decreases and then increases at higher energies. Small-angle scattering prevails at all energies. Some characteristic features can be seen that provide information on the geometrical structure of the colliding particles and the relevant dynamical mechanisms. The steep Gaussian peak at small angles is followed by the exponential (Orear) regime with some shoulders and dips, and then by a power-law decrease. Results from various theoretical approaches are compared with experimental data. Phenomenological models claiming to describe this process are reviewed. The unitarity condition predicts an exponential fall for the differential cross section with an additional substructure to occur exactly between the low momentum transfer diffraction cone and a power-law, hard parton scattering regime under high momentum transfer. Data on the interference of the Coulomb and nuclear parts of amplitudes at extremely small angles provide the value of the real part of the forward scattering amplitude. The real part of the elastic scattering amplitude and the contribution of inelastic processes to the imaginary part of this amplitude (the so-called overlap function) are also discussed. Problems related to the scaling behavior of the differential cross section are considered. The power-law regime at highest momentum transfer is briefly described.
NASA Astrophysics Data System (ADS)
Csörgő, T.; Nemes, F.
2014-01-01
The Bialas-Bzdak model of elastic proton-proton scattering is generalized to the case when the real part of the parton-parton level forward scattering amplitude is nonvanishing. Such a generalization enables the model to describe well the dip region of the differential cross-section of elastic scattering at the intersecting storage rings (ISR) energies, and improves significantly the ability of the model to describe also the recent TOTEM data at √ {s} = 7 TeV LHC energy. Within this framework, both the increase of the total cross-section, as well as the decrease of the location of the dip with increasing colliding energies, is related to the increase of the quark-diquark distance and to the increase of the "fragility" of the protons with increasing energies. In addition, we present and test the validity of two new phenomenological relations: one of them relates the total p+p cross-section to an effective, model-independent proton radius, while the other relates the position of the dip in the differential elastic cross-section to the measured value of the total cross-section.
Study of proton resonance structure in {sup 27}P via resonant elastic scattering of {sup 26}Si+p
Jung, H. S.; Lee, C. S.; Kwon, Y. K.; Moon, J. Y.; Lee, J. H.; Yun, C. C.; Kubono, S.; Yamaguchi, H.; Hashimoto, T.; Kahl, D.; Hayakawa, S.; Choi, Seonho; Kim, M. J.; Kim, Y. H.; Kim, Y. K.; Park, J. S.; Kim, E. J.; Moon, C.-B.; Teranishi, T.; Wakabayashi, Y.; and others
2012-11-12
A measurement of resonant elastic scattering of {sup 26}Si+p was performed with a thick target using a {sup 26}Si radioactive ion beam at the CRIB (CNS Radioactive Ion Beam separator) of the Center for Nuclear Study (CNS), the University of Tokyo. The excitation function of {sup 27}P was measured successfully with the inverse kinematics method through a covered the range of excitation energies from E{sub x}{approx} 2.3 to 3.8 MeV, providing information about the resonance structure of this nucleus. The properties of these resonances are important to better determine the production rates of {sup 26}Si(p,g){sup 27}P reaction, which is one of the astrophysically important nuclear reactions to understand the production of the {sup 26}Al. Some new resonant states have been investigated, and determined their resonance parameters, such as excitation energies, proton partial widths, and spin-parities by R-matrix calculation.
Parity violation in the elastic scattering from the proton in Hall A
Souder, Paul
1992-06-01
We are planning to measure the parity-violating electroweak asymmetry in the scattering of polarized electrons from hydrogen. We expect to obtain unique information about the weak form factors of the nucleon emphasizing the possible contributions of strange quarks to the weak vector matrix elements involved. Helium and deuterium and other possible targets of interest.
NASA Astrophysics Data System (ADS)
Yang, Y. Y.; Liu, X.; Pang, D. Y.
2016-09-01
Experimental data show that the elastic scattering cross sections of the neutron-rich nucleus 11Be are greatly reduced by the coupling effects from the breakup channels, while those of the proton-rich nucleus 8B are not. Such difference is found to persist in results of systematic calculations of 8B elastic scattering from 208Pb at 60 and 170.3 MeV and from 64Zn at 32 and 86 MeV, and 11Be elastic scattering from 208Pb at 55 and 143 MeV and from 64Zn at 29 and 66 MeV with the continuum-discretized coupled channel (CDCC) method. The Coulomb and centrifugal barriers experienced by the valence proton in the ground state of 8B, which do not exist for the valence neutron in the ground state of 11Be, are found to be the reason for such differences in the angular distributions of elastic scattering cross sections of these two weakly bound nuclei.
Two-Photon Exchange Effects in Elastic Electron-Proton Scattering
NASA Astrophysics Data System (ADS)
Johnson, Myriam James
Two methods, Rosenbluth separation and polarization transfer, can be used to extract the proton form factor ratio mupG Ep/GMp, but they do not yield the same results. It is thought that the disagreement is due to two photon exchange corrections to the dierential cross sections. High precision proton Rosenbluth extractions were carried out at 102 kinematics points spanning 16 values of momentum transfer Q2, from 0.40 to 5.76 GeV 2. Reduced cross sections were found to 1.1% or better for Q 2 less than 3 GeV2, increasing to 4% at 5.76 GeV 2. The form factor ratios were determined to 1:5-3% for Q2 < 1.5 GeV2, increasing to 9% by 3 GeV2 and rapidly above. Our data agrees with prior Rosenbluth, improving upon it the 1.0 - 2.0 GeV2 range to conclusively show a separation from polarization transfer where it had not been certain before. In addition, reduced cross sections at each Q2 were tested for nonlinearity in the angular variable. Such a departure from linearity would be a signature of two photon exchange effects, and prior data had not been suciently precise to show nonzero curvature. Our data begins to hint at negative curvature but does not yet show a signicant departure from zero.
Two-Photon Exchange Effects in Elastic Electron-Proton Scattering
Johnson, Myriam James
2013-08-01
Two methods, Rosenbluth separation and polarization transfer, can be used to extract the proton form factor ratio μp G_{Ep}/G_{Mp}, but they do not yield the same results. It is thought that the disagreement is due to two photon exchange corrections to the differential cross sections. High precision proton Rosenbluth extractions were carried out at 102 kinematics points spanning 16 values of momentum transfer Q^{2}, from 0.40 to 5.76 GeV^{2}. Reduced cross sections were found to 1.1% or better for Q^{2} less than 3 GeV^{2} increasing to 4% at 5.76 GeV^{2} The form factor ratios were determined to 1:5-3% for Q^{2} < 1.5 GeV^{2}, increasing to 9% by 3 GeV^{2} and rapidly above. Our data agrees with prior Rosenbluth, improving upon it the 1.0 - 2.0 GeV^{2} range to conclusively show a separation from polarization transfer where it had not been certain before. In addition, reduced cross sections at each Q^{2} were tested for nonlinearity in the angular variable. Such a departure from linearity would be a signature of two photon exchange effects, and prior data had not been sufficiently precise to show nonzero curvature. Our data begins to hint at negative curvature but does not yet show a significant departure from zero.
Crespo, R.; Johnson, R.C.; Tostevin, J.A. )
1994-12-01
The validity of the local density approximation as applied to the construction of the nucleon-nucleus optical potential is studied. A Wentzel-Kramers-Brillouin (WKB) local equivalent potential to the second-order term of the Kerman, McManus, and Thaler (KMT) multiple scattering expansion of the nucleon nucleus optical potential is derived. Assuming that the nucleon-nucleon transition amplitude is on the energy shell, we compare the microscopic KMT optical potential with the approximate potential deduced from the nuclear matter limit by use of the local density approximation. Calculations are presented for the nucleon-[sup 16]O system at 135 and 200 MeV incident energies. It is shown that the use of the local density prescription leads to surface peaking of the optical potential. This effect is absent from the second-order term of the optical potential derived microscopically from the KMT approach.
Waidyawansa, Dinayadura Buddhini
2013-08-01
The beam normal single spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable of the imaginary part of the two-photon exchange process. Moreover, it is a potential source of false asymmetry in parity violating electron scattering experiments. The Q{sub weak} experiment uses parity violating electron scattering to make a direct measurement of the weak charge of the proton. The targeted 4% measurement of the weak charge of the proton probes for parity violating new physics beyond the Standard Model. The beam normal single spin asymmetry at Q{sub weak} kinematics is at least three orders of magnitude larger than 5 ppb precision of the parity violating asymmetry. To better understand this parity conserving background, the Q{sub weak} Collaboration has performed elastic scattering measurements with fully transversely polarized electron beam on the proton and aluminum. This dissertation presents the analysis of the 3% measurement (1.3% statistical and 2.6% systematic) of beam normal single spin asymmetry in electronproton scattering at a Q2 of 0.025 (GeV/c)2. It is the most precise existing measurement of beam normal single spin asymmetry available at the time. A measurement of this precision helps to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process.
NASA Astrophysics Data System (ADS)
Qattan, I. A.; Alsaad, A.
2011-05-01
The most recent electron-proton elastic scattering data were re-analyzed using an empirical parametrization of the two-photon-exchange (TPE) effect contributions to σR. The TPE effect contribution F(Q2,ɛ) was double Taylor series expanded as a polynomial of order n keeping only terms linear in ɛ to account for the experimentally observed and verified linearity of the Rosenbluth plots. We fix the ratio R=GEp/GMp to be that obtained from a fit to the recoil-polarization data and parametrize σR first by a three-parameter formula (fit I) and then by a two-parameter formula (fit III). In contrast to previous analyses, the fit parameter GMp2 as obtained from these fits is either smaller or equal to the values obtained from our conventional Rosenbluth fit (fit II) but never larger. The ratio g(Q2)/GMp2 which represents the ratio of the TPE and one-photon-exchange (OPE) effect contributions to the intercept of σR is large and it ranges 3%-88%. The ratio R1γ⊗2γ=τf(Q2)/GEp2 which represents the ratio of the TPE and OPE effect contributions to the slope of σR is also large, reaching a value of 12.0-14.4 at Q2= 5.25 (GeV/c)2. The ratio R1γ⊗2γ as obtained from fits I and III is consistent, within error, with those obtained from previous analyses. Our formulas seem to explain the linearity of σR. Moreover, our analysis shows that the extracted GEp2 and GMp2 using the conventional Rosenbluth separation method can in fact be broken into the usual OPE and TPE contributions. Therefore, σR can in fact be derived under weaker conditions than those imposed by the Born approximation. Our results show that the TPE amplitudes, g(Q2)/GMp2 and f(Q2)/GMp2, are sizable and grow with Q2 value up to Q2~ 6 (GeV/c)2 in agreement with previous studies. A revision of and comparison to previous analyses are also presented.
Measurement of the analyzing power for pion proton elastic scattering between 471 and 687 MeV/c
Mokhtari-Amirmajdi, A.
1985-06-01
The analyzing power, A/sub N/, has been measured for ..pi../sup + -/p..--> pi../sup + -/p at 471, 547, 625, and 687 MeV/c in an angular range corresponding to -0.9 less than or equal to cos theta/sub cm/ less than or equal to 0.8. A polarized proton target with polarization axis normal to the scattering plane was used. The scattered pion and recoil proton were detected in coincidence, using a magnetic spectrometer and a wire chamber/scintillator array, except in cases where one of the particles was kinematically inaccessible. Statistical uncertainties in the data are as low as 0.02; systematic uncertainties are estimated to be less than 3%. The ..pi../sup -/p data are characterized by large values of analyzing power, and rapid variations in the angular distribution with incident momentum. The measurements are compared with the results of existing partial wave analysis.
NASA Astrophysics Data System (ADS)
Pakou, A.; Soukeras, V.; Cappuzzello, F.; Acosta, L.; Agodi, C.; Aslanoglou, X.; Calabrese, S.; Carbone, D.; Cavallaro, M.; Foti, A.; Keeley, N.; Marquinez-Duran, G.; Martel, I.; Mazzocco, M.; Parascandolo, C.; Pierroutsakou, D.; Rusek, K.; Sgouros, O.; Strano, E.; Zagatto, V. A. B.
2016-07-01
Elastic scattering measurements were performed for the 7Li+p system in inverse kinematics at energies of 16, 25, 35, and 38.1 MeV and for the 7Li+d system at 38.1 MeV. The heavy ejectiles were detected by the large acceptance MAGNEX spectrometer at the Laboratori Nazionali del Sud in Catania, Italy. The results are analyzed using the Jeukenne-Lejeune-Mahaux and continuum discretized coupled channel frameworks. In the latter case the cluster structure of 7Li proves to be critical for the theoretical interpretation of the experimental results.
NASA Astrophysics Data System (ADS)
Lukyanov, V. K.; Kadrev, D. N.; Zemlyanaya, E. V.; Spasova, K.; Lukyanov, K. V.; Antonov, A. N.; Gaidarov, M. K.
2015-03-01
The density distributions of 10Be and 11Be nuclei obtained within the quantum Monte Carlo model and the generator coordinate method are used to calculate the microscopic optical potentials (OPs) and cross sections of elastic scattering of these nuclei on protons and 12C at energies E <100 MeV/nucleon. The real part of the OP is calculated using the folding model with the exchange terms included, while the imaginary part of the OP that reproduces the phase of scattering is obtained in the high-energy approximation. In this hybrid model of OP the free parameters are the depths of the real and imaginary parts obtained by fitting the experimental data. The well-known energy dependence of the volume integrals is used as a physical constraint to resolve the ambiguities of the parameter values. The role of the spin-orbit potential and the surface contribution to the OP is studied for an adequate description of available experimental elastic scattering cross-section data. Also, the cluster model, in which 11Be consists of a n -halo and the 10Be core, is adopted. Within the latter, the breakup cross sections of 11Be nucleus on 9Be,93Nb,181Ta , and 238U targets and momentum distributions of 10Be fragments are calculated and compared with the existing experimental data.
Subedi, Adesh
2014-12-01
The Qweak experiment has taken data to make a 2.5% measurement of parity violating elastic e+p asymmetry in the four momentum transfer region of 0.0250 (GeV/c)^{2}. This asymmetry is proportional to the weak charge of the proton, which is related to the weak mixing angle, sin^{2}(theta_W). The final Qweak measurement will provide the most precise measurement of the weak mixing angle below the Z^{0} pole to test the Standard Model prediction. A description of the experimental apparatus is provided in this dissertation. The experiment was carried out using a longitudinally polarized electron beam of up to 180 microampere on a 34.5 cm long unpolarized liquid hydrogen target. The Qweak target is not only the world's highest cryogenic target ever built for a parity experiment but also is the least noisy target. This dissertation provides a detailed description of this target and presents a thorough analysis of the target performance. Statistical analysis of Run 1 data, collected between Feb - May 2011, is done to extract a blinded parity violating asymmetry of size -299.7 ± 13.4 (stat.) ± 17.2 (syst.) ± 68 (blinding) parts-per-billion. This resulted in a preliminary proton's weak charge of value 0.0865 ± 0.0085, a 9% measurement. Based on this blinded asymmetry, the weak mixing angle was determined to be sin^{2}(theta_W) = 0.23429 ± 0.00211.
Elastic and inelastic scattering of polarized protons from carbon-12 at 400, 600, and 700 MeV
Jones, K.W.
1984-04-01
Good resolution cross section and analyzing power (p vector, p') data for many states in /sup 12/C up to an excitation energy of 21 MeV and spanning a momentum transfer range of 0.3 to 2.1 fm/sup -1/ were obtained using the High Resolution Spectrometer at the Clinton P. Anderson Meson Physics Facility at incident beam energies of 398, 597, and 698 MeV. Optical model potentials were obtained from the elastic scattering data. Inelastic data were analyzed in the Distorted Wave Impulse Approximation using the Love-Franey effective nucleon-nucleon interaction. The energy dependent isoscalar natural parity cross sections were underestimated, while phase difficulties were encountered in fitting analyzing powers. The energy independent isovector natural parity cross sections were reasonably reproduced, but analyzing powers were not, the calculations yielding positive trends whereas the data are of opposite sign. The energy independent isoscalar and isovector unnatural parity cross sections were quite well reproduced up to moderate momentum transfers, and striking successes were observed for some analyzing power data. Systematics of energy dependence together with the results of the DWIA calculations permitted the assignment of spin, parity and isospin quantum numbers to states in the 18-21 MeV excitation region. 64 references.
Elastic and diffractive scattering at D0
Edwards, Tamsin; /Manchester U.
2004-04-01
The first search for diffractively produced Z bosons in the muon decay channel is presented, using a data set collected by the D0 detector at the Fermilab Tevatron at {radical}s = 1.96 TeV between April and September 2003, corresponding to an integrated luminosity of approximately 110 pb{sup -1}. The first dN/d|t| distribution for proton-antiproton elastic scattering at this c.o.m. energy is also presented, using data collected by the D0 Forward Proton Detector between January and May 2002. The measured slope is reproduced by theoretical predictions.
Proton resonance scattering of 7Be
Yamaguchi, H.; Saito, A.; He, J. J.; Wakabayashi, Y.; Amadio, G.; Fujikawa, H.; Kubono, S.; Khiem, L. H.; Niikura, M.; Kwon, Y. K.; Teranishi, T.; Nishimura, S.; Togano, Y.; Iwasa, N.; Inafuku, K.
2006-07-12
We have studied the proton resonance scattering of 7Be by using a pure 7Be beam produced at CRIB (CNS Radioactive Ion Beam separator; CNS stands for Center of Nuclear Study, University of Tokyo). The excitation function of 8B was measured up to the excitation energy of 6.8 MeV, with the thick-target method. The excited states of 8B higher than 3.5 MeV were not known by the past experiments. This proton elastic scattering is also of importance in relation with the 7Be(p,{gamma})8B reaction, which is a key reaction in the standard solar model.
Proton resonance scattering of 7Be
NASA Astrophysics Data System (ADS)
Yamaguchi, H.; Saito, A.; He, J. J.; Wakabayashi, Y.; Amadio, G.; Fujikawa, H.; Kubono, S.; Khiem, L. H.; Kwon, Y. K.; Niikura, M.; Teranishi, T.; Nishimura, S.; Togano, Y.; Iwasa, N.; Inafuku, K.
2006-07-01
We have studied the proton resonance scattering of 7Be by using a pure 7Be beam produced at CRIB (CNS Radioactive Ion Beam separator; CNS stands for Center of Nuclear Study, University of Tokyo). The excitation function of 8B was measured up to the excitation energy of 6.8 MeV, with the thick-target method. The excited states of 8B higher than 3.5 MeV were not known by the past experiments. This proton elastic scattering is also of importance in relation with the 7Be(p,γ)8B reaction, which is a key reaction in the standard solar model.
Elastic forward scattering of gluons
NASA Astrophysics Data System (ADS)
Ermolaev, B. I.
1995-06-01
The colour octet and singlet parts of the elastic gg→ gg-scattering amplitude are evaluated in the Regge kinematical region s≫- t in the LLA, with iπ-terms taken into account, by constructing and solving a set of the infrared evolution equations.
NASA Astrophysics Data System (ADS)
Spasova, K.; Lukyanov, V. K.; Kadrev, D. N.; Antonov, A. N.; Zemlyanaya, E. V.; Lukyanov, K. V.; Gaidarov, M. K.
2016-06-01
The elastic scattering cross-sections of 10,11Be on protons and 12C at energy E < 100 MeV/nucleon using microscopically calculated optical potentials (OP) are presented. The real OP is obtained by a folding procedure with effective NN interactions, while the imaginary OP is estimated within the high energy approximation (HEA). The spin-orbit part of the OP is also included. The characteristics of the breakup processes of 11Be on different nuclear targets are also considered. The cross-sections of diffractive breakup and stripping reactions of 11Be on 9Be, 93Nb, 181Ta and 238U at energy E = 63 MeV/nucleon and the longitudinal momentum distributions of 10Be fragments produced in the breakup of 11Be on these nuclei are presented. The results are in a good agreement with the available experimental data, in particular the obtained widths of about 50 MeV/c are closed to the empirical ones.
Johnson, Kirsten S; Laskin, Alexander; Jimenez, Jose L; Shutthanandan, V; Molina, Luisa T; Salcedo, D; Dzepina, K; Molina, Mario J
2008-09-01
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 off-line under 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 SO_{4}^{2-}) and AMS-measured sulfate during the most of the campaign. PESA-measured hydrogen mass was separated into sulfate H and organic H mass fractions assuming the only major contributions were (NH_{4})_{2}SO_{4} 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 vacuum. However ~25% of the organics does remain under vacuum, which is only possible with low vapor pressure compounds, and which supports the presence of high molecular weight and/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 NH_{4}Cl. 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.
Energy evolution of the large-t elastic scattering and its correlation with multiparticle production
Troshin, S. M.
2013-04-15
It is emphasized that the collective dynamics associated with color confinement is dominating over a point-like mechanism related to a scattering of the proton constituents at the currently available values of the momentum transferred in proton elastic scattering at the LHC. Deep-elastic scattering and its role in the dissimilation of the absorptive and reflective asymptotic scattering mechanisms are discussed with emphasis on the experimental signatures associated with the multiparticle production processes.
Evaluation of the Proton Charge Radius from Electron–Proton Scattering
Arrington, John; Sick, Ingo
2015-09-15
In light of the proton radius puzzle, the discrepancy between measurements of the proton charge radius from muonic hydrogen and those from electronic hydrogen and electron–proton (e–p) scattering measurements, we re-examine the charge radius extractions from electron scattering measurements. We provide a recommended value for the proton root-mean-square charge radius, r{sub E} = 0.879 ± 0.011 fm, based on a global examination of elastic e–p scattering data. The uncertainties include contributions to account for tension between different data sets and inconsistencies between radii using different extraction procedures.
NASA Astrophysics Data System (ADS)
Moon, J. Y.; Lee, C. S.; Lee, J. H.; Yun, C. C.; Kim, J. C.; Youn, M.; Kubono, S.; Teranishi, T.; He, J. J.; Notani, M.; Nishimura, S.; Nishimura, M.; Guimarães, V.; Lihitenthaler, R. F.; Kato, S.
2005-12-01
The observational space map of 1.809-MeV gamma rays - coming from the decay of 26Al - taken by COMPTEL requires the sources and their nucleosynthetic activity to be unveiled. One suggestion for the observation is the explosive hydrogen burning process which occurs in novae or X-ray bursts. Two capture reactions such as 25 Al(p,γ)26Si and 26Si(p,γ)27P are of great importance in the production of 1.809-MeV gamma rays. Resonance states within the Gamow window should be precisely known to determine their reaction rates. As for the latter reaction, only a few levels in 27P have been known above the proton threshold in comparison with many levels known in its mirror nucleus 27Mg. We studied proton resonances in 26Si and 27P by the elastic scattering at low energies, respectively using low-energy 25Al and 26Si radioactive ion beams available from the CRIB facility at CNS, University of Tokyo. We carried out an experiment to investigate proton resonances in 26Si up to EC.M. = 3.016 MeV, especially to determine the resonance parameters of the states at Ex = 7.019 and 8.120 MeV. We also measured the elastic scattering of p + 26Si up to EC.M. = 3.290 MeV.
Lukyanov, V. K. Zemlyanaya, E. V.; Lukyanov, K. V.
2015-01-15
The {sup 11}Li scattering and breakup on protons is considered under the assumption that the {sup 11}Li nucleus consists of two interacting clusters, which are a c = {sup 9}Li core and a h = 2n dineutron halo. The single-particle density of the {sup 11}Li nucleus, amicroscopic optical potential, and the cross section for {sup 11}Li+p scattering for various choices of cluster shape are obtained and analyzed by folding the density distribution for either cluster with the probability density for the relative motion of two clusters. A comparison with experimental data of the scattering cross section at low, 60–75 MeV, and intermediate, 700 MeV, energies is performed. The momentum distribution of c fragments upon {sup 11}Li breakup is calculated and studied with a help of the obtained p + c and p + h microscopic optical potentials.
Spatial measure of reaction size in proton scattering
NASA Astrophysics Data System (ADS)
Ito, Makoto; Iwasaki, Masataka; Otani, Reiji; Tomita, Masashi
2016-06-01
The microscopic coupled-channel (MCC) calculations for proton + 12C inelastic scattering are performed in the energy range of Ep = 29.95 MeV to 65 MeV. The nuclear interactions for the proton -12C system are constructed from the folding model, which employs the internal wave function of 12C, obtained from the 3α resonating group method (3α RGM), and an effective nucleon-nucleon interaction of the density-dependent Michigan three-range Yukawa (DDM3Y). The MCC calculation with the 3α RGM + DDM3Y nicely reproduces all of the differential cross sections for elastic and inelastic scattering in the angular range of θc.m. = 30° to 120°. We introduce a scattering radius, which characterizes a spatial size of the scattering area, from partial wave decompositions of an angle-integrated cross section. The scattering radii for the elastic scattering and the various inelastic channels, which involve the rotational or vibrational excitations and the 3α excitations in 12C, are derived. We found that the scattering radii for the inelastic channels with a well developed 3α structure are strongly enhanced in comparison to the scattering radii for the elastic and collective channels. This enhancement of the scattering radius for the 3α channel strongly suggests that the scattering radius is sensitive to a size of the intrinsic structure of the finally excited state in the scattering process.
NASA Astrophysics Data System (ADS)
He, J. J.; Kubono, S.; Teranishi, T.; Notani, M.; Baba, H.; Nishimura, S.; Moon, J. Y.; Nishimura, M.; Michimasa, S.; Iwasaki, H.; Yanagisawa, Y.; Hokoiwa, N.; Kibe, M.; Lee, J. H.; Kato, S.; Gono, Y.; Lee, C. S.
2008-04-01
Proton resonances in 22Mg have been investigated by the resonant elastic scattering of 21 Na + p . The 21Na beam with a mean energy of 4.00 MeV/nucleon was separated by the CNS radioactive-ion-beam separator (CRIB) and bombarded a thick ( CH2 n target. The energy spectra of recoiled protons were measured at scattering angles of θc.m. ≈ 172° , 146° , respectively. Several excited states observed before have been confirmed including two states (at 6.616, 6.796 MeV) observed at TRIUMF. A new state at 7.06 MeV has been observed, and another new one at 7.28 MeV is tentatively identified due to its low statistics. The proton resonant parameters were deduced from an R -matrix analysis of the differential cross-section data with a SAMMY-M6-BETA code. The astrophysical implication for the 18 Ne(α, p)21 Na reaction has been briefly discussed.
Proton-Proton Scattering at 105 Mev and 75 Mev
DOE R&D Accomplishments Database
Birge, R. W.; Kruse, U. E.; Ramsey, N. F.
1951-01-31
The scattering of protons by protons provides an important method for studying the nature of nuclear forces. Recent proton-proton scattering experiments at energies as high as thirty Mev{sup 1} have failed to show any appreciable contribution to the cross section from higher angular momentum states, but it is necessary to bring in tensor forces to explain the magnitude of the observed cross section.
Asymmetry Measurement in the Elastic Pion-Proton Scattering at 1.94 and 2.07 GeV/c
Alekseev, I. G.; Budkovsky, P. E.; Kanavets, V. P.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Sulimov, A. D.; Svirida, D. N.; Zhurkin, V. V.; Bazhanov, N. A.; Bunyatova, E. I.; Zolin, L. S.; Beloglazov, Yu. A.; Filimonov, E. A.; Kovalev, A. I.; Kruglov, S. P.; Novinsky, D. V.; Shchedrov, V. A.; Sumachev, V. V.
2007-06-13
Latest results by the ITEP-PNPI collaboration on the asymmetry in the {pi}+p elastic scattering are presented. The data were obtained for the first time in the region of backward angles with low cross section, where the predictions of the partial wave analyses are not reliable. The results at 1.94 GeV/c are in favor of the older KH80 analysis and show noticeable deviation from the latest FA06 solution by GWU group. At 2.07 GeV/c very low cross section did not allow to achieve good accuracy. Yet the data do not follow any of the PWA predictions and definitely disagree with SP06 analysis.
Inversion problem for ion-atom differential elastic scattering.
NASA Technical Reports Server (NTRS)
Rich, W. G.; Bobbio, S. M.; Champion, R. L.; Doverspike, L. D.
1971-01-01
The paper describes a practical application of Remler's (1971) method by which one constructs a set of phase shifts from high resolution measurements of the differential elastic scattering of protons by rare-gas atoms. These JWKB phase shifts are then formally inverted to determine the corresponding intermolecular potentials. The validity of the method is demonstrated by comparing an intermolecular potential obtained by direct inversion of experimental data with a fairly accurate calculation by Wolniewicz (1965).
Hadronic uncertainties in the elastic scattering of supersymmetric dark matter
Ellis, John; Olive, Keith A.; Savage, Christopher
2008-03-15
We review the uncertainties in the spin-independent and spin-dependent elastic scattering cross sections of supersymmetric dark matter particles on protons and neutrons. We propagate the uncertainties in quark masses and hadronic matrix elements that are related to the {pi}-nucleon {sigma} term and the spin content of the nucleon. By far the largest single uncertainty is that in spin-independent scattering induced by our ignorance of the
Neutron densities in 120Sn observed by polarized proton scattering
NASA Astrophysics Data System (ADS)
Sakaguchi, H.; Takeda, H.; Taki, T.; Yosoi, M.; Itoh, M.; Kawabata, T.; Ishikawa, T.; Uchida, M.; Tsukahara, N.; Noro, T.; Yoshimura, M.; Fujimura, H.; Yoshida, H.; Obayashi, E.; Tamii, A.; Akimune, H.
2001-06-01
Cross sections, analyzing powers and spin rotation parameters of proton elastic scattering from 58Ni and 120Sn have been measured at intermediate energies. By elastic scattering off N~=Z nuclei like 58Ni at intermediate energies we can study medium modification of the nucleon-nucleon (NN) interaction inside the nucleus, because proton distributions in target nuclei are constrained by charge distributions measured by electron scattering and neutron distributions can be assumed to be the same as proton's. In order to explain our experimental data of 58Ni at large scattering angles, it was found to be necessary to use experimental densities deduced from charge densities measured by electron scattering and to modify the coupling constants and the masses of exchanged σ and ω mesons in the RIA, assuming linear dependencies of meson properties to nuclear densities. Parameters of the medium effect have been searched to reproduce the data. For N≠Z nuclei, neutron density distribution can be extracted from the elastic scattering, assuming the same medium modifications fixed by the 58Ni data and using proton distributions obtained from charge distributions. We have searched neutron density distributions obtained from charge distributions. We have searched neutron density distribution so as to reproduce 120Sn data at the proton incident energy of 300 MeV. Deduced neutron distribution has an increase at the nuclear center, which is consistent with the 3s1/2 orbit wave function as expected in 120Sn. At energies other than 300 MeV, experimental data of 120Sn have been also well reproduced by the neutron distribution obtained at 300 MeV. .
Simulation of nucleon elastic scattering in the MARS14 code system
Igor L Rakhno et al.
2001-11-26
Correct modeling of nucleon elastic scattering is of special importance in many applications at high energy accelerators, such as deep penetration, beam loss and collimation studies. In present paper, the work performed to update the MARS elastic scattering model at E < 5 GeV is described. Modern evaluated nuclear data as well as fitting formulae are used in the new model. For protons as projectiles, Coulomb scattering and Coulomb-nuclear interference are taken into account in addition to nuclear elastic scattering. Comparisons with experimental angular distributions and calculations by means of other codes are presented.
Elastic electron scattering by ethyl vinyl ether
NASA Astrophysics Data System (ADS)
Khakoo, M. A.; Hong, L.; Kim, B.; Winstead, C.; McKoy, V.
2010-02-01
We report measured and calculated results for elastic scattering of low-energy electrons by ethyl vinyl ether (ethoxyethene), a prototype system for studying indirect dissociative attachment processes that may play a role in DNA damage. The integral cross section displays the expected π* shape resonance. The agreement between the calculated and measured cross sections is generally good.
NASA Astrophysics Data System (ADS)
Kłusek-Gawenda, Mariola; Schäfer, Wolfgang; Szczurek, Antoni
2016-10-01
We discuss the two-gluon exchange contribution (formally three-loops) to elastic photon-photon scattering in the high-energy approximation. The elastic γγ → γγ amplitude is given in the impact-factor representation for all helicity configurations and finite quark masses. We discuss the importance of including the charm quark, which contribution, due to interference, can enhance the cross section considerably. We investigate the contribution to the γγ → γγ amplitude from the soft region, by studying its dependence on nonperturbative gluon mass. Helicity-flip contributions are shown to be much smaller than helicity-conserving ones. We identify region(s) of phase space where the two-gluon exchange contribution becomes important ingredient compared to box and nonperturbative VDM-Regge mechanisms considered in the literature. Consequences for the AA → AAγγ reaction are discussed. Several differential distributions are shown. A feasibility study to observe the effect of two-gluon exchange is presented. We perform a similar analysis for the pp → ppγγ reaction. Only by imposing severe cuts on Mγγ and a narrow window on photon transverse momenta the two gluon contribution becomes comparable to the box contribution but the corresponding cross section is rather small.
Hydrogen analysis for granite using proton-proton elastic recoil coincidence spectrometry.
Komatsubara, T; Sasa, K; Ohshima, H; Kimura, H; Tajima, Y; Takahashi, T; Ishii, S; Yamato, Y; Kurosawa, M
2008-07-01
In an effort to develop DS02, a new radiation dosimetry system for the atomic bomb survivors of Hiroshima and Nagasaki, measurements of neutron-induced activities have provided valuable information to reconstruct the radiation situation at the time of the bombings. In Hiroshima, the depth profile of (152)Eu activity measured in a granite pillar of the Motoyasu Bridge (128 m from the hypocenter) was compared with that calculated using the DS02 methodology. For calculation of the (152)Eu production due to the thermal-neutron activation reaction, (151)Eu(n,gamma)(152)Eu, information on the hydrogen content in granite is important because the transport and slowing-down process of neutrons penetrating into the pillar is strongly affected by collisions with the protons of hydrogen. In this study, proton-proton elastic recoil coincidence spectrometry has been used to deduce the proton density in the Motoyasu pillar granite. Slices of granite samples were irradiated by a 20 MeV proton beam, and the energies of scattered and recoil protons were measured with a coincidence method. The water concentration in the pillar granite was evaluated to be 0.30 +/- 0.07%wt. This result is consistent with earlier data on adsorptive water (II) and bound water obtained by the Karl Fisher method. PMID:18509666
Hydrogen analysis for granite using proton-proton elastic recoil coincidence spectrometry.
Komatsubara, T; Sasa, K; Ohshima, H; Kimura, H; Tajima, Y; Takahashi, T; Ishii, S; Yamato, Y; Kurosawa, M
2008-07-01
In an effort to develop DS02, a new radiation dosimetry system for the atomic bomb survivors of Hiroshima and Nagasaki, measurements of neutron-induced activities have provided valuable information to reconstruct the radiation situation at the time of the bombings. In Hiroshima, the depth profile of (152)Eu activity measured in a granite pillar of the Motoyasu Bridge (128 m from the hypocenter) was compared with that calculated using the DS02 methodology. For calculation of the (152)Eu production due to the thermal-neutron activation reaction, (151)Eu(n,gamma)(152)Eu, information on the hydrogen content in granite is important because the transport and slowing-down process of neutrons penetrating into the pillar is strongly affected by collisions with the protons of hydrogen. In this study, proton-proton elastic recoil coincidence spectrometry has been used to deduce the proton density in the Motoyasu pillar granite. Slices of granite samples were irradiated by a 20 MeV proton beam, and the energies of scattered and recoil protons were measured with a coincidence method. The water concentration in the pillar granite was evaluated to be 0.30 +/- 0.07%wt. This result is consistent with earlier data on adsorptive water (II) and bound water obtained by the Karl Fisher method.
Positron elastic scattering from alkaline earth targets
NASA Astrophysics Data System (ADS)
Poveda, Luis A.; Assafrão, Denise; Mohallem, José R.
2016-07-01
A previously reported model potential approach [Poveda et al., Phys. Rev. A 87, 052702 (2013)] was extended to study low energy positron elastic scattering from beryllium and magnesium. The cross sections were computed for energies ranging from 10-5 eV up to well above the positronium formation threshold. The present results are in good agreement with previous reports, including the prediction of a p-wave resonance in the cross section for magnesium. The emergence of this shape resonance is connected to a trend observed in the evolution of the partial wave cross section in going from Be to Mg target. This trend lead us to speculate that a sharp d-wave resonance should be observed in positron elastic scattering from calcium. The positron-target binding energies are investigated in detail, both using the scattering information and by direct computation of the bound state energies using the model potentials. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2016-70120-y
Elastic scattering, fusion, and breakup of light exotic nuclei
NASA Astrophysics Data System (ADS)
Kolata, J. J.; Guimarães, V.; Aguilera, E. F.
2016-05-01
The present status of fusion reactions involving light ( A < 20) radioactive projectiles at energies around the Coulomb barrier ( E < 10 MeV per nucleon) is reviewed, emphasizing measurements made within the last decade. Data on elastic scattering (providing total reaction cross section information) and breakup channels for the involved systems, demonstrating the relationship between these and the fusion channel, are also reviewed. Similarities and differences in the behavior of fusion and total reaction cross section data concerning halo nuclei, weakly-bound but less exotic projectiles, and strongly-bound systems are discussed. One difference in the behavior of fusion excitation functions near the Coulomb barrier seems to emerge between neutron-halo and proton-halo systems. The role of charge has been investigated by comparing the fusion excitation functions, properly scaled, for different neutron- and proton-rich systems. Possible physical explanations for the observed differences are also reviewed.
Elastic Electron Scattering from Tritium and Helium-3
DOE R&D Accomplishments Database
Collard, H.; Hofstadter, R.; Hughes, E. B.; Johansson, A.; Yearian, M. R.; Day, R. B.; Wagner, R. T.
1964-10-01
The mirror nuclei of tritium and helium-3 have been studied by the method of elastic electron scattering. Absolute cross sections have been measured for incident electron energies in the range 110 - 690 MeV at scattering angles lying between 40 degrees and 135 degrees in this energy range. The data have been interpreted in a straightforward manner and form factors are given for the distributions of charge and magnetic moment in the two nuclei over a range of four-momentum transfer squared 1.0 - 8.0 F{sup -2}. Model-independent radii of the charge and magnetic moment distributions are given and an attempt is made to deduce form factors describing the spatial distribution of the protons in tritium and helium-3.
Multiple scattering of proton via stochastic differential equations
NASA Astrophysics Data System (ADS)
Kia, M. R.; Noshad, Houshyar
2015-08-01
Multiple scattering of protons through a target is explained by a set of coupled stochastic differential equations. The motion of protons in matter is calculated by analytical random sampling from Moliere and Landau probability density functions (PDF). To satisfy the Vavilov theory, the moments for energy distribution of a 49.1 MeV proton beam in aluminum target are obtained. The skewness for the PDF of energy demonstrates that the energy distribution of protons in thin thickness becomes a Landau function, whereas, by increasing the thickness of the target it does not follow a Gaussian function completely. Afterwards, the depth-dose distributions are calculated for a 60 MeV proton beam traversing soft tissue and for a 160 MeV proton beam travelling through water. The results prove that when elastic scattering is taken into account, the Bragg-peak position is decreased, while the dose deposited in the Bragg region is increased. The results obtained in this article are benchmarked by comparison of our results with the experimental data reported in the literature.
Inverse obstacle scattering for elastic waves
NASA Astrophysics Data System (ADS)
Li, Peijun; Wang, Yuliang; Wang, Zewen; Zhao, Yue
2016-11-01
Consider the scattering of a time-harmonic plane wave by a rigid obstacle which is embedded in an open space filled with a homogeneous and isotropic elastic medium. An exact transparent boundary condition is introduced to reduce the scattering problem into a boundary value problem in a bounded domain. Given the incident field, the direct problem is to determine the displacement of the wave field from the known obstacle; the inverse problem is to determine the obstacle’s surface from the measurement of the displacement on an artificial boundary enclosing the obstacle. In this paper, we consider both the direct and inverse problems. The direct problem is shown to have a unique weak solution by examining its variational formulation. The domain derivative is derived for the displacement with respect to the variation of the surface. A continuation method with respect to the frequency is developed for the inverse problem. Numerical experiments are presented to demonstrate the effectiveness of the proposed method.
Quasi-Elastic Light Scattering in Ophthalmology
NASA Astrophysics Data System (ADS)
Ansari, Rafat R.
The eye is not just a "window to the soul"; it can also be a "window to the human body." The eye is built like a camera. Light which travels from the cornea to the retina traverses through tissues that are representative of nearly every tissue type and fluid type in the human body. Therefore, it is possible to diagnose ocular and systemic diseases through the eye. Quasi-elastic light scattering (QELS) also known as dynamic light scattering (DLS) is a laboratory technique routinely used in the characterization of macromolecular dispersions. QELS instrumentation has now become more compact, sensitive, flexible, and easy to use. These developments have made QELS/DLS an important tool in ophthalmic research where disease can be detected early and noninvasively before the clinical symptoms appear.
Two-photon exchange in elastic ep scattering and the status of the OLYMPUS experiment
NASA Astrophysics Data System (ADS)
Hasell, Douglas; Olympus Collaboration
2014-09-01
Two-photon exchange in elastic ep scattering is believed to explain the observed discrepancy in the proton electric to magnetic form factor ratio, μpGEp /GMp , measured by Rosenbluth separation and by polarization transfer methods. To quantitatively determine the contribution of two-photon exchange to elastic scattering the OLYMPUS experiment was proposed and operated at the DESY laboratory in Hamburg, Germany to measure the ratio in the elastic scattering cross sections, σe+ p /σe- p . The OLYMPUS experiment used the positron and electron beams of the DORIS storage ring at a beam energy of 2.01 GeV incident on a windowless, internal, hydrogen gas target. A left/right symmetric detector measured the rates for elastic scattering over a broad kinematic range together with a redundant set of luminosity monitors. Approximately 4.45 fb-1 of integrated luminosity was collected. The current status of the OLYMPUS analysis will be presented.
Subcritical scattering from buried elastic shells.
Lucifredi, Irena; Schmidt, Henrik
2006-12-01
Buried objects have been largely undetectable by traditional high-frequency sonars due to their insignificant bottom penetration. Further, even a high grazing angle sonar approach is vastly limited by the coverage rate dictated by the finite water depth, making the detection and classification of buried objects using low frequency, subcritical sonar an interesting alternative. On the other hand, such a concept would require classification clues different from the traditional high-resolution imaging and shadows to maintain low false alarm rates. A potential alternative, even for buried targets, is classification based on the acoustic signatures of man-made elastic targets. However, the elastic responses of buried and proud targets are significantly different. The objective of this work is to identify, analyze, and explain some of the effects of the sediment and the proximity of the seabed interface on the scattering of sound from completely and partially buried elastic shells. The analysis was performed using focused array processing of data from the GOATS98 experiment carried out jointly by MIT and SACLANTCEN, and a new hybrid modeling capability combining a virtual source-or wave-field superposition-approach with an exact spectral integral representation of the Green's functions for a stratified ocean waveguide, incorporating all multiple scattering between the object and the seabed. Among the principal results is the demonstration of the significant role of structural circumferential waves in converting incident, evanescent waves into backscattered body waves, emanating to the receivers at supercritical grazing angles, in effect making the target appear closer to the sonar than predicted by traditional ray theory.
Electron Elastic-Scattering Cross-Section Database
National Institute of Standards and Technology Data Gateway
SRD 64 NIST Electron Elastic-Scattering Cross-Section Database (PC database, no charge) This database provides values of differential elastic-scattering cross sections, corresponding total elastic-scattering cross sections, phase shifts, and transport cross sections for elements with atomic numbers from 1 to 96 and for electron energies between 50 eV and 20,000 eV (in steps of 1 eV).
Coherency in neutrino-nucleus elastic scattering
NASA Astrophysics Data System (ADS)
Kerman, S.; Sharma, V.; Deniz, M.; Wong, H. T.; Chen, J.-W.; Li, H. B.; Lin, S. T.; Liu, C.-P.; Yue, Q.; Texono Collaboration
2016-06-01
Neutrino-nucleus elastic scattering provides a unique laboratory to study the quantum mechanical coherency effects in electroweak interactions, towards which several experimental programs are being actively pursued. We report results of our quantitative studies on the transitions towards decoherency. A parameter (α ) is identified to describe the degree of coherency, and its variations with incoming neutrino energy, detector threshold, and target nucleus are studied. The ranges of α that can be probed with realistic neutrino experiments are derived, indicating complementarity between projects with different sources and targets. Uncertainties in nuclear physics and in α would constrain sensitivities in probing physics beyond the standard model. The maximum neutrino energies corresponding to α >0.95 are derived.
25Al+p Elastic Scattering with CRIB
NASA Astrophysics Data System (ADS)
Pearson, Jonty; Chen, A. A.; Kubono, S.; Yamaguchi, H.; He, J. J.; Khlem, L. H.; Salto, A.; Amadio, G.; Fajikawa, H.; Nilkura, M.; Wakabayashi, Y.; Teranishi, T.; Nishimura, S.; Togano, Y.; Odahara, A.; Moon, J. Y.; Kwon, Y. K.; Cherubini, S.; Pizzone, R.; La Cognata, M.
The present rate of the 25 Al(p,γ)26 Si reaction suffers from significant uncertainties due to the lack of relevant structure information in the compound nucleus 26 Si. An 25 Al+p elastic-scattering experiment in inverse kinematics was performed using the CRIB facility at the CNS at the Uni- versity of Tokyo, Japan, to try and improve current understanding. The 2 H(24 Mg,n)25 Al reaction was used to produce a 7.5 MeV/A 25 Al radioactive beam with intensities of ˜ 106 pps at the secondary CH2 target position. Protons were detected in silicon E?E telescopes and a center-of- mass energy range of 3 MeV was scanned, reaching up to about 8.5 MeV in excitation energy in 26 Si.
Generalizations of Karp's theorem to elastic scattering theory
NASA Astrophysics Data System (ADS)
Tuong, Ha-Duong
Karp's theorem states that if the far field pattern corresponding to the scattering of a time-harmonic acoustic plane wave by a sound-soft obstacle in R2 is invariant under the group of rotations, then the scatterer is a circle. The theorem is generalized to the elastic scattering problems and the axisymmetric scatterers in R3.
Support minimized inversion of acoustic and elastic wave scattering
Safaeinili, A.
1994-04-24
This report discusses the following topics on support minimized inversion of acoustic and elastic wave scattering: Minimum support inversion; forward modelling of elastodynamic wave scattering; minimum support linearized acoustic inversion; support minimized nonlinear acoustic inversion without absolute phase; and support minimized nonlinear elastic inversion.
Elastic Scattering LIDAR Data Acquisition Visualization and Analysis
1999-10-12
ELASTIC/EVIEW is a software system that controls an elastic scattering atmospheric Light Detection and Ranging (LIDAR) instrument. It can acquire elastic scattering LIDAR data using this system and produce images of one, two, and three-dimensional atmospheric data on particulates and other atmospheric pollutants. The user interface is a modern menu driven syatem with appropriate support for user configuration and printing files.
The Proton Coulomb Form Factor from Polarized Inclusive e-p Scattering
Chris Harris
2001-08-01
The proton form factors provide information on the fundamental properties of the proton and provide a test for models based on QCD. In 1998 at Jefferson Lab (JLAB) in Newport News, VA, experiment E93026 measured the inclusive e-p scattering cross section from a polarized ammonia (15NH3) target at a four momentum transfer squared of Q2 = 0.5 (GeV/c)2. Longitudinally polarized electrons were scattered from the polarized target and the scattered electron was detected. Data has been analyzed to obtain the asymmetry from elastically scattered electrons from hydrogen in 15NH3. The asymmetry, Ap, has been used to determine the proton elastic form factor GEp. The result is consistent with the dipole model and data from previous experiments. However, due to the choice of kinematics, the uncertainty in the measurement is large.
Improved Optics For Quasi-Elastic Light Scattering
NASA Technical Reports Server (NTRS)
Cheung, Harry Michael
1995-01-01
Improved optical train devised for use in light-scattering measurements of quasi-elastic light scattering (QELS) and laser spectroscopy. Measurements performed on solutions, microemulsions, micellular solutions, and colloidal dispersions. Simultaneous measurements of total intensity and fluctuations in total intensity of light scattered from sample at various angles provides data used, in conjunction with diffusion coefficients, to compute sizes of particles in sample.
pp Elastic Scattering: New Results from EDDA (COSY)
Scobel, W.; EDDA Collaboration
2000-12-31
In the EDDA experiment excitation functions of proton{endash}proton elastic scattering are studied with narrow steps in the projectile momentum range from 0.8 to 3.4 GeV/c and angular range 35{degree} {le} {Theta}{sub cm} {le} 90 {degree} with a detector providing {Delta}{Theta}{sub cm} {approx} 1.4{degree} resolution and 85% solid angle coverage. Measurements are performed continuously during projectile acceleration on the Cooler Synchrotron COSY. In phase 1 of the experiment spin-averaged differential cross sections d{sigma}/d{Omega} have been measured with an internal CH{sub 2} fiber target; background corrections were derived from measurements with a carbon fiber target and from Monte Carlo simulations of inelastic pp contributions. The results provide excitation functions and angular distributions of high precision and internal consistency. In phase 2 of the experiment excitation functions of the analyzing power A{sub N} have been measured using a polarized (P{ge}75%) atomic beam target, and those of the polarization correlation parameters A{sub NN}, A{sub SS} and A{sub SL} will be measured later on with the polarized COSY beam. The measured excitation functions are compared to recent phase shift analyses, and their impact on them is discussed. So far evidence for narrow structures was neither found in the spin-averaged cross sections nor in the analyzing powers.
A Quasi-Elastic Neutron Scattering Study of the Dynamics of Electrically Constrained Water.
Fuchs, Elmar C; Bitschnau, Brigitte; Wexler, Adam D; Woisetschläger, Jakob; Freund, Friedemann T
2015-12-31
We have measured the quasi-elastic neutron scattering (QENS) of an electrohydrodynamic liquid bridge formed between two beakers of pure water when a high voltage is applied, a setup allowing to investigate water under high-voltage without high currents. From this experiment two proton populations were distinguished: one consisting of protons strongly bound to oxygen atoms (immobile population, elastic component) and a second one of quasi-free protons (mobile population, inelastic component) both detected by QENS. The diffusion coefficient of the quasi-free protons was found to be D = (26 ± 10) × 10(-5) cm(2) s(-1) with a jump length lav ∼ 3 Å and an average residence time of τ0 = 0.55 ± 0.08 ps. The associated proton mobility in the proton channel of the bridge is ∼9.34 × 10(-7) m(2) V(-1) s(-1), twice as fast as diffusion-based proton mobility in bulk water. It also matches the so-called electrohydrodynamic or "apparent" charge mobility, an experimental quantity which so far has lacked molecular interpretation. These results further corroborate the proton channel model for liquid water under high voltage and give new insights into the molecular mechanisms behind electrohydrodynamic charge transport phenomena and delocalization of protons in liquid water. PMID:26643863
A Quasi-Elastic Neutron Scattering Study of the Dynamics of Electrically Constrained Water.
Fuchs, Elmar C; Bitschnau, Brigitte; Wexler, Adam D; Woisetschläger, Jakob; Freund, Friedemann T
2015-12-31
We have measured the quasi-elastic neutron scattering (QENS) of an electrohydrodynamic liquid bridge formed between two beakers of pure water when a high voltage is applied, a setup allowing to investigate water under high-voltage without high currents. From this experiment two proton populations were distinguished: one consisting of protons strongly bound to oxygen atoms (immobile population, elastic component) and a second one of quasi-free protons (mobile population, inelastic component) both detected by QENS. The diffusion coefficient of the quasi-free protons was found to be D = (26 ± 10) × 10(-5) cm(2) s(-1) with a jump length lav ∼ 3 Å and an average residence time of τ0 = 0.55 ± 0.08 ps. The associated proton mobility in the proton channel of the bridge is ∼9.34 × 10(-7) m(2) V(-1) s(-1), twice as fast as diffusion-based proton mobility in bulk water. It also matches the so-called electrohydrodynamic or "apparent" charge mobility, an experimental quantity which so far has lacked molecular interpretation. These results further corroborate the proton channel model for liquid water under high voltage and give new insights into the molecular mechanisms behind electrohydrodynamic charge transport phenomena and delocalization of protons in liquid water.
An Examination of Proton Charge Radius Extractions from e–p Scattering Data
Arrington, John
2015-09-15
A detailed examination of issues associated with proton radius extractions from elastic electron–proton scattering experiments is presented. Sources of systematic uncertainty and model dependence in the extractions are discussed, with an emphasis on how these may impact the proton charge and magnetic radii. A comparison of recent Mainz data to previous world data is presented, highlighting the difference in treatment of systematic uncertainties as well as tension between different data sets. We find several issues that suggest that larger uncertainties than previously quoted may be appropriate, but do not find any corrections which would resolve the proton radius puzzle.
Numerical solution of acoustic scattering by finite perforated elastic plates
NASA Astrophysics Data System (ADS)
Cavalieri, A. V. G.; Wolf, W. R.; Jaworski, J. W.
2016-04-01
We present a numerical method to compute the acoustic field scattered by finite perforated elastic plates. A boundary element method is developed to solve the Helmholtz equation subjected to boundary conditions related to the plate vibration. These boundary conditions are recast in terms of the vibration modes of the plate and its porosity, which enables a direct solution procedure. A parametric study is performed for a two-dimensional problem whereby a cantilevered perforated elastic plate scatters sound from a point quadrupole near the free edge. Both elasticity and porosity tend to diminish the scattered sound, in agreement with previous work considering semi-infinite plates. Finite elastic plates are shown to reduce acoustic scattering when excited at high Helmholtz numbers k0 based on the plate length. However, at low k0, finite elastic plates produce only modest reductions or, in cases related to structural resonance, an increase to the scattered sound level relative to the rigid case. Porosity, on the other hand, is shown to be more effective in reducing the radiated sound for low k0. The combined beneficial effects of elasticity and porosity are shown to be effective in reducing the scattered sound for a broader range of k0 for perforated elastic plates.
Proton radius from electron scattering data
NASA Astrophysics Data System (ADS)
Higinbotham, Douglas W.; Kabir, Al Amin; Lin, Vincent; Meekins, David; Norum, Blaine; Sawatzky, Brad
2016-05-01
Background: The proton charge radius extracted from recent muonic hydrogen Lamb shift measurements is significantly smaller than that extracted from atomic hydrogen and electron scattering measurements. The discrepancy has become known as the proton radius puzzle. Purpose: In an attempt to understand the discrepancy, we review high-precision electron scattering results from Mainz, Jefferson Lab, Saskatoon, and Stanford. Methods: We make use of stepwise regression techniques using the F test as well as the Akaike information criterion to systematically determine the predictive variables to use for a given set and range of electron scattering data as well as to provide multivariate error estimates. Results: Starting with the precision, low four-momentum transfer (Q2) data from Mainz (1980) and Saskatoon (1974), we find that a stepwise regression of the Maclaurin series using the F test as well as the Akaike information criterion justify using a linear extrapolation which yields a value for the proton radius that is consistent with the result obtained from muonic hydrogen measurements. Applying the same Maclaurin series and statistical criteria to the 2014 Rosenbluth results on GE from Mainz, we again find that the stepwise regression tends to favor a radius consistent with the muonic hydrogen radius but produces results that are extremely sensitive to the range of data included in the fit. Making use of the high-Q2 data on GE to select functions which extrapolate to high Q2, we find that a Padé (N =M =1 ) statistical model works remarkably well, as does a dipole function with a 0.84 fm radius, GE(Q2) =(1+Q2/0.66 GeV2) -2 . Conclusions: Rigorous applications of stepwise regression techniques and multivariate error estimates result in the extraction of a proton charge radius that is consistent with the muonic hydrogen result of 0.84 fm; either from linear extrapolation of the extremely-low-Q2 data or by use of the Padé approximant for extrapolation using a larger
On the Large-t Elastic Scattering at √{s} = 7 TeV
NASA Astrophysics Data System (ADS)
Troshin, S. M.; Tyurin, N. E.
2012-06-01
We discuss discrimination of the scattering mechanisms on the basis of functional dependencies of the large-t elastic scattering suggested by the recent data from the TOTEM experiment. It is shown that Orear exponent is in a better agreement with the data than the power-like dependence used by the TOTEM. This implies that the collective dynamics is dominating over the point-like mechanism related to the scattering of the proton constituents. We also emphasize that vanishing of the helicity-flip amplitudes contributions at the LHC energies would result in appearance of the dip-bump structures at higher values of transferred momenta.
Emission of neutron-proton and proton-proton pairs in neutrino scattering
NASA Astrophysics Data System (ADS)
Ruiz Simo, I.; Amaro, J. E.; Barbaro, M. B.; De Pace, A.; Caballero, J. A.; Megias, G. D.; Donnelly, T. W.
2016-11-01
We use a recently developed model of relativistic meson-exchange currents to compute the neutron-proton and proton-proton yields in (νμ ,μ-) scattering from 12C in the 2p-2h channel. We compute the response functions and cross sections with the relativistic Fermi gas model for different kinematics from intermediate to high momentum transfers. We find a large contribution of neutron-proton configurations in the initial state, as compared to proton-proton pairs. In the case of charge-changing neutrino scattering the 2p-2h cross section of proton-proton emission (i.e., np in the initial state) is much larger than for neutron-proton emission (i.e., two neutrons in the initial state) by a (ω , q)-dependent factor. The different emission probabilities of distinct species of nucleon pairs are produced in our model only by meson-exchange currents, mainly by the Δ isobar current. We also analyze other effects including exchange contributions and the effect of the axial and vector currents.
Hadron-hadron elastic scattering at large momentum transfers
Rubinstein, R.
1983-05-01
Cross sections for ..pi../sup + -/p, K/sup + -/p and p/sup + -/p elastic scattering for incident momenta above a few tens of GeV/c and momentum transfers in the range 1 less than or equal to -t less than or equal to 10 (GeV/c)/sup 2/ have recently been measured. The data are reviewed, and compared with existing models of elastic scattering.
Inelastic Scattering Of Electrons By Protons
DOE R&D Accomplishments Database
Cone, A. A.; Chen, K. W.; Dunning, J. R. Jr.; Hartwig, G.; Ramsey, N. F.; Walker, J. K.; Wilson, R.
1966-12-01
The inelastic scattering of electrons by protons has been measured at incident electron energies up to 5 BeV/c and momentum transfers q{sup 2}=4(BeV/c){sup 2}. Excitation of known nucleon resonances at M=1238, 1512, 1688 and possibly 1920 MeV have been observed. The calculations for the resonance at M=1238 MeV have been compared with calculations by Adler based on the dispersion theory of Chew, Goldberger, Low and Nambu. The agreement is good. Qualitative models are discussed for the other resonances.
Effects of shear elasticity on sea bed scattering: numerical examples.
Ivakin, A N; Jackson, D R
1998-01-01
It is known that marine sediments can support both compressional and shear waves. However, published work on scattering from irregular elastic media has not examined the influence of shear on sea bed scattering in detail. A perturbation model previously developed by the authors for joint roughness-volume scattering is used to study the effects of elasticity for three sea bed types: sedimentary rock, sand with high shear speed, and sand with "normal" shear wave speed. Both bistatic and monostatic cases are considered. For sedimentary rock it is found that shear elasticity tends to increase the importance of volume scattering and decrease the importance of roughness scattering relative to the fluid case. Shear effects are shown to be small for sands.
Measurement of proton inelastic scattering cross sections on fluorine
NASA Astrophysics Data System (ADS)
Chiari, M.; Caciolli, A.; Calzolai, G.; Climent-Font, A.; Lucarelli, F.; Nava, S.
2016-10-01
Differential cross-sections for proton inelastic scattering on fluorine, 19F(p,p')19F, from the first five excited levels of 19F at 110, 197, 1346, 1459 and 1554 keV were measured for beam energies from 3 to 7 MeV at a scattering angle of 150° using a LiF thin target (50 μg/cm2) evaporated on a self-supporting C thin film (30 μg/cm2). Absolute differential cross-sections were calculated with a method not dependent on the absolute values of collected beam charge and detector solid angle. The validity of the measured inelastic scattering cross sections was then tested by successfully reproducing EBS spectra collected from a thick Teflon (CF2) target. As a practical application of these measured inelastic scattering cross sections in elastic backscattering spectroscopy (EBS), the feasibility of quantitative light element (C, N and O) analysis in aerosol particulate matter samples collected on Teflon by EBS measurements and spectra simulation is demonstrated.
12C+p resonant elastic scattering in the Maya active target
NASA Astrophysics Data System (ADS)
Sambi, S.; Raabe, R.; Borge, M. J. G.; Caamano, M.; Damoy, S.; Fernández-Domínguez, B.; Flavigny, F.; Fynbo, H.; Gibelin, J.; Grinyer, G. F.; Heinz, A.; Jonson, B.; Khodery, M.; Nilsson, T.; Orlandi, R.; Pancin, J.; Perez-Loureiro, D.; Randisi, G.; Ribeiro, G.; Roger, T.; Suzuki, D.; Tengblad, O.; Thies, R.; Datta, U.
2015-03-01
In a proof-of-principle measurement, the Maya active target detector was employed for a 12C( p, p) resonant elastic scattering experiment in inverse kinematics. The excitation energy region from 0 to 3MeV above the proton breakup threshold in 13N was investigated in a single measurement. By using the capability of the detector to localize the reaction vertex and record the tracks of the recoiling protons, data covering a large solid angle could be utilized, at the same time keeping an energy resolution comparable with that of direct-kinematics measurements. The excitation spectrum in 13N was fitted using the R-matrix formalism. The level parameters extracted are in good agreement with previous studies. The active target proved its potential for the study of resonant elastic scattering in inverse kinematics with radioactive beams, when detection efficiency is of primary importance.
rvec p + sup 13 rvec C elastic scattering at 500 MeV
Tanaka, N.
1990-01-01
For the first time, an elastic scattering experiment was performed at LAMPF using polarized protons and a polarized target nucleus ({rvec p} + {sup 13}{rvec C}). The analyzing powers (A{sub ooon}({Theta})) and (A{sub oonn}({Theta})) were measured using an incident beam energy of 500 MeV over the laboratory angular range of 10{degree}--30{degree}. Motivation for the experiment and some preliminary results and conclusions are presented. 12 refs., 7 figs.
Quasi-elastic nuclear scattering at high energies
NASA Technical Reports Server (NTRS)
Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.
1992-01-01
The quasi-elastic scattering of two nuclei is considered in the high-energy optical model. Energy loss and momentum transfer spectra for projectile ions are evaluated in terms of an inelastic multiple-scattering series corresponding to multiple knockout of target nucleons. The leading-order correction to the coherent projectile approximation is evaluated. Calculations are compared with experiments.
Effects of Auger electron elastic scattering in quantitative AES
NASA Astrophysics Data System (ADS)
Jablonski, Aleksander
1987-09-01
The Monte Carlo algorithm was developed for simulating the trajectories of electrons elastically scattered in the solid. The distribution of scattering angles was determined using the partial wave expansion method. This algorithm was used to establish the influence of Auger electron elastic collisions on the results of quantitative AES analysis. The calculations were performed for the most pronounced KLL, L 3 MM and M 5NN Auger transitions. It turned out that due to the elastic collisions the Auger electron signal is decreased by up to 10%. The corresponding decreased of the escape depth of Auger electrons reaches 30% as compared with the value derived from the inelastic mean free path. The values of the inelastic mean free path resulting from the overalyer method may be strongly affected by elastic scattering of Auger electrons.
Dissipation induced by phonon elastic scattering in crystals
Li, Guolong; Ren, Zhongzhou; Zhang, Xin
2016-01-01
We demonstrate that the phonon elastic scattering leads to a dominant dissipation in crystals at low temperature. The two-level systems (TLSs) should be responsible for the elastic scattering, whereas the dissipation induced by static-point defects (SPDs) can not be neglected. One purpose of this work is to show how the energy splitting distribution of the TLS ensemble affects the dissipation. Besides, this article displays the proportion of phonon-TLS elastic scattering to total phonon dissipation. The coupling coefficient of phonon-SPD scattering and the constant P0 of the TLS distribution are important that we estimate their magnitudes in this paper. Our results is useful to understand the phonon dissipation mechanism, and give some clues to improve the performance of mechanical resonators, apply the desired defects, or reveal the atom configuration in lattice structure of disordered crystals. PMID:27669517
Multiparticle production in deep inelastic lepton scattering and soft proton proton collisions
Werner, K.
1987-06-01
We demonstrate how the theoretical knowledge about multiparticle production in deep inelastic lepton scattering can be incorporated into a multistring model for low p/sub t/ proton proton collisions. 25 refs., 8 figs.
Scattering from elastic sea beds: first-order theory.
Jackson, D R; Ivakin, A N
1998-01-01
A perturbation model for high-frequency sound scattering from an irregular elastic sea bed is considered. The sea bed is assumed homogeneous on the average and two kinds of irregularities are assumed to cause scattering: roughness of the water-sea bed interface and volume inhomogeneities of the sediment mass density and the speeds of compressional and shear waves. The first-order small perturbation approximation is used to obtain expressions for the scattering amplitude and bistatic scattering strength. The angular dependence of the scattering strength is calculated for sedimentary rock and the influence of shear elasticity is examined by comparison with the case of a fluid bottom. Shear effects are shown to be strong and complicated.
Variational calculation of electron elastic scattering by atomic helium
NASA Astrophysics Data System (ADS)
Chernek, P. J.
1982-12-01
The elastic-scattering of electrons from atomic helium in the ground state is investigated. It is shown that for low energy incident electrons the scattering problem reduced to solving an ordinary integro-differential equation for the scattering wave-function. A method is discussed to obtain approximate solutions to the integro-differential equation by variational principles. The extremum condition of the variational method is formulated into a general N x N matrix equation which reduces to a 2 x 2 eigen-value matrix problem for the phase-shift of the scattering electron. An algorithm is presented to obtain the collisional cross-section for elastic scattering as a function of incident electron energy.
Effect of three-nucleon interactions in p-(3)He elastic scattering.
Viviani, M; Girlanda, L; Kievsky, A; Marcucci, L E
2013-10-25
We present a detailed study of the effect of different three-nucleon interactions in p-(3)He elastic scattering at low energies. In particular, two interactions have been considered: one derived from effective field theory at next-to-next-to-leading order and one derived from a more phenomenological point of view-the so-called Illinois model. The four-nucleon scattering observables are calculated by using the Kohn variational principle and the hyperspherical harmonics technique, and the results are compared with available experimental data. We have found that the inclusion of both interactions improves the agreement with the experimental data, in particular, for the proton vector analyzing power.
NASA Astrophysics Data System (ADS)
Deur, Alexandre
1999-10-01
The Jefferson Lab beam energy measurement in Hall A using the elastic ep scattering will be described. This new, non-magnetic, energy measurement method allows a ( triangle E/E=10-4 ) precision. First-order corrections are canceled by the measurements of the electron and proton scattering angles for two symmetric kinematics. The measurement principle will be presented as well as the device and measurement results. Comparison with independent magnetic energy measurements of the same accuracy will be shown. This project is the result of a collaboration between the LPC: université Blaise Pascal/in2p3), Saclay and Jefferson Lab.
Elastic and inelastic scattering of He atoms from Bi(111)
NASA Astrophysics Data System (ADS)
Tamtögl, A.; Mayrhofer-Reinhartshuber, M.; Balak, N.; Ernst, W. E.; Rieder, K. H.
2010-08-01
Elastic and inelastic scattering of helium atoms has been used to study the Bi(111) surface. Sharp diffraction peaks are found with results in excellent agreement with previous structure determinations of the Bi(111) surface. The rather large first order peaks with respect to the zero order peak indicate a stronger surface corrugation than observed in helium scattering from other metallic surfaces. Time-of-flight spectra of scattered He atoms clearly reveal two inelastic scattering maxima, which allow a first report on phonon creation and annihilation events on the Bi(111) surface. An estimate of the group velocity shows that the phonon creation peak is likely to correspond to a Rayleigh mode.
Simulations of micro-swimmer scattering by soft elastic filaments
NASA Astrophysics Data System (ADS)
Ledesma-Aguilar, Rodrigo; Yeomans, Julia M.
2012-11-01
The locomotion of microorganisms in the presence of elastic filaments, such as hairs and flagella, is very common in biological systems. We perform a theoretical study, using a simple point-force hydrodynamic model, to analyse the scattering of a dipolar swimmer and semiflexible filaments. Our swimmers consist of active dumbbells that undergo a non-reciprocal swimming stroke leading to locomotion. Fluid-mediated interactions with the elastic chains are modelled using Oseen-level hydrodynamics. We explore the effect of the elasticity of the filaments on the swimmer velocity and orientation. We acknowledge support from Marie Curie Actions FP7-People-EIF-2010 no. 273406.
Evidence for virtual Compton scattering from the proton
van den Brand, J.F.J.; Ent, R.; Anthony, P.L.; Arnold, R.G.; Arrington, J.; Beise, E.J.; Belz, J.E.; Bosted, P.E.; Bulten, H.; Chapman, M.S.; Coulter, K.P.; Dietrich, F.S.; Epstein, M.; Filippone, B.W.; Gao, H.; Gearhart, R.A.; Geesaman, D.F.; Hansen, J.; Holt, R.J.; Jackson, H.E.; Jones, C.E.; Keppel, C.E.; Kinney, E.R.; Kuhn, S.; Lee, K.; Lorenzon, W.; Lung, A.; Makins, N.C.R.; Margaziotis, D.J.; McKeown, R.D.; Milner, R.G.; Mueller, B.; Napolitano, J.; Nelson, J.; O`Neill, T.G.; Papavassiliou, V.; Petratos, G.G.; Potterveld, D.H.; Rock, S.E.; Spengos, M.; Szalata, Z.M.; Tao, L.H.; van Bibber, K.; Wasson, D.A.; White, J.L.; Zeidman, B. ||||||||||
1995-11-01
In virtual Compton scattering an electron is scattered off a nucleon such that the nucleon emits a photon. We show that these events can be selected experimentally, and present the first evidence for virtual Compton scattering from the proton in data obtained at the Stanford Linear Accelerator Center. The angular and energy dependence of the data is well described by a calculation that includes the coherent sum of electron and proton radiation.
Elastic scattering of electrons from Rb, Cs and Fr atoms
NASA Astrophysics Data System (ADS)
Gangwar, R. K.; Tripathi, A. N.; Sharma, L.; Srivastava, R.
2010-04-01
Differential, integrated elastic, momentum-transfer and total cross sections as well as differential S, T and U spin parameters for scattering of electrons from rubidium, caesium and francium atoms in the incident energy range up to 300 eV are calculated using a relativistic Dirac equation. The projectile electron-target atom interaction is represented by both real and complex parameter-free optical potentials for obtaining the solution of a Dirac equation for scattered electrons. The Dirac-Fock wavefunctions have been used to represent the Rb, Cs and Fr target atoms. The results of differential cross sections and spin asymmetry parameter S for e-Rb and e-Cs have been compared with the available experimental and theoretical results. Detailed results are reported for the elastic scattering of electrons from the ground states of a francium atom for the first time in the wide range of incident electron energies. The results of electron-Fr elastic scattering show the similar features to those obtained in the case of e-Rb and e-Cs elastic scattering.
Measurement of the Wolfenstein parameters for proton-proton and proton-neutron scattering at 500 MeV
Marshall, J.A.
1984-07-01
Using liquid hydrogen and liquid deuterium targets respectively, forward angle (ten degrees to sixty degrees in the center of Mass) free proton-proton and quasielastic proton-proton and proton-neutron triple scattering data at 500 MeV have been obtained using the high resolution spectrometer at the Los Alamos Meson Physics Facility. The data are in reasonable agreement with recent predictions from phase shift analyses, indicating that the proton-nucleon scattering amplitudes are fairly well determined at 500 MeV. 32 references.
Study of 11Li and 10,11Be nuclei through elastic scattering and breakup reactions
NASA Astrophysics Data System (ADS)
Gaidarov, M. K.; Lukyanov, V. K.; Kadrev, D. N.; Zemlyanaya, E. V.; Antonov, A. N.; Lukyanov, K. V.; Spasova, K.
2016-01-01
The hybrid model of the microscopic optical potential (OP) is applied to calculate the 11Li+p, 10,11Be+p, and 10,11Be+12C elastic scattering cross sections at energies E < 100 MeV/nucleon. The OP's contain the folding-model real part (ReOP) with the direct and exchange terms included, while its imaginary part (ImOP) is derived within the high-energy approximation (HEA) theory. For the 11Li+p elastic scattering, the microscopic large-scale shell model (LSSM) density of 11Li is used, while the density distributions of 10,11Be nuclei obtained within the quantum Monte Carlo (QMC) model and the generator coordinate method (GCM) are utilized to calculate the microscopic OPs and cross sections of elastic scattering of these nuclei on protons and 12C. The depths of the real and imaginary parts of OP are fitted to the elastic scattering data, being simultaneously adjusted to reproduce the true energy dependence of the corresponding volume integrals. Also, the cluster models, in which 11Li consists of 2n-halo and the 9Li core having its own LSSM form of density and 11Be consists of a n-halo and the 10Be core, are adopted. Within the latter, we give predictions for the longitudinal momentum distributions of 9Li fragments produced in the breakup of 11Li at 62 MeV/nucleon on a proton target. It is shown that our results for the diffraction and stripping reaction cross sections in 11Be scattering on 9Be, 93Nb, 181Ta, and 238U targets at 63 MeV/nucleon are in a good agreement with the available experimental data.
Energy distribution of elastically scattered electrons from double layer samples
NASA Astrophysics Data System (ADS)
Tőkési, K.; Varga, D.
2016-02-01
We present a theoretical description of the spectra of electrons elastically scattered from thin double layered Au-C samples. The analysis is based on the Monte Carlo simulation of the recoil and Doppler effects in reflection and transmission geometries of the scattering at a fixed angle of 44.3 ° and a primary energy of 40 keV. The relativistic correction is taken into account. Besides the experimentally measurable energy distributions the simulations give many partial distributions separately, depending on the number of elastic scatterings (single, and multiple scatterings of different types). Furthermore, we present detailed analytical calculations for the main parameters of the single scattering, taking into account both the ideal scattering geometry, i.e. infinitesimally small angular range, and the effect of the real, finite angular range used in the measurements. We show our results for intensity ratios, peak shifts and broadenings for four cases of measurement geometries and layer thicknesses. While in the peak intensity ratios of gold and carbon for transmission geometries were found to be in good agreement with the results of the single scattering model, especially large deviations were obtained in reflection geometries. The separation of the peaks, depending on the geometry and the thickness, generally smaller, and the peak width generally larger than it can be expected from the nominal values of the primary energy, scattering angle, and mean kinetic energy of the atoms. We also show that the peaks are asymmetric even for the case of the single scattering due to the finite solid angle. Finally, we present a qualitative comparison with the experimental data. We find our resulting energy distribution of elastically scattered electrons to be in good agreement with recent measurements.
Contraband detection via neutron elastic scattering
Gomberg, H.J.; Charatis, G.; Brundage, J.
1993-04-01
Reliable detection of explosives and narcotics depends on generating signatures of compounds which characterize them. Major explosives and also alkaloid narcotics contain unique concentrations of Carbon (C), Nitrogen (N), and Oxygen (O). The kinematic energy shifts of neutrons scattered through angles larger than 140{degrees} allows separate determinations of C, N, and O; ratios of N/C and O/C together give clear signatures of the presence of plastic explosives or narcotics. The ability to detect these signatures under conditions similar to those that would obtain for airport screening has been demonstrated for neutrons for energies less {le} 3 MeV. Strong N resonances and a deep window for scattering from O enhance the confidence of element quantification. Detection of contraband in large cargo containers presents a much more difficult problem. Use of higher energy neutrons is now being tested for shielding penetration, so narcotic signatures could be identified behind the shielding of cargo containers. Scattered neutron spectra, or {open_quotes}signatures{close_quotes} of different organic compounds will be presented.
Direct and inverse scattering by an elastic inclusion
NASA Astrophysics Data System (ADS)
Pelekanos, George
1997-11-01
The problem of two-dimensional scattering of elastic waves by an elastic inclusion can be formulated in terms of a domain integral equation, in which the grad-div operator acts on a vector potential. The vector potential is the spatial convolution of a Green's function with the product of the density and the displacement over the domain of interest. The first part of the thesis treats the numerical solution of the direct problem. Following similar work done in electromagnetics we employ a Galerkin approximation using a weak form of the integral equation and rooftop functions, as both expansion and test functions. The determination of the approximate elastic field is thus reduced to an algebraic problem. We present some numerical results for coaxially coated cylinders with constant Lame coefficients and variable densities. The numerical results are compared with existing analytical solutions. The second part of the thesis is concerned with the inverse problem of determining the density of an elastic inclusion from a knowledge of how the inclusion scatters known incident elastic waves. A modified gradient method which is based on the integral representation of the field is used for the solution of the inverse problem. The algorithm employed is an extension of the Kleinman- Van den Berg method to elasticity, and involves an iterative determination of both the unknown density and the shape of the inclusion. The synthetic data used in the inversion algorithm is obtained using the numerical solution of the direct problem developed in the first part of the dissertation.
Rayleigh scattering and nonlinear inversion of elastic waves
Gritto, R.
1995-12-01
Rayleigh scattering of elastic waves by an inclusion is investigated and the limitations determined. In the near field of the inhomogeneity, the scattered waves are up to a factor of 300 stronger than in the far field, excluding the application of the far field Rayleigh approximation for this range. The investigation of the relative error as a function of parameter perturbation shows a range of applicability broader than previously assumed, with errors of 37% and 17% for perturbations of {minus}100% and +100%, respectively. The validity range for the Rayleigh limit is controlled by large inequalities, and therefore, the exact limit is determined as a function of various parameter configurations, resulting in surprisingly high values of up to k{sub p}R = 0.9. The nonlinear scattering problem can be solved by inverting for equivalent source terms (moments) of the scatterer, before the elastic parameters are determined. The nonlinear dependence between the moments and the elastic parameters reveals a strong asymmetry around the origin, which will produce different results for weak scattering approximations depending on the sign of the anomaly. Numerical modeling of cross hole situations shows that near field terms are important to yield correct estimates of the inhomogeneities in the vicinity of the receivers, while a few well positioned sources and receivers considerably increase the angular coverage, and thus the model resolution of the inversion parameters. The pattern of scattered energy by an inhomogeneity is complicated and varies depending on the object, the wavelength of the incident wave, and the elastic parameters involved. Therefore, it is necessary to investigate the direction of scattered amplitudes to determine the best survey geometry.
Do we understand elastic scattering up to LHC energies?
NASA Astrophysics Data System (ADS)
Soffer, Jacques
2013-04-01
The measurements of high energy ¯pp and pp elastic at ISR, SPS, and Tevatron colliders have provided usefull informations on the behavior of the scattering amplitude. A large step in energy domain is accomplished with the LHC collider presently running, giving a unique opportunity to improve our knowledge on the asymptotic regime of the elastic scattering amplitude and to verify the validity of our theoretical approach, to describe the total cross section σtot(s), the total elastic cross section σel(s), the ratio of the real to imaginary parts of the forward amplitude ρ(s) and the differential cross section dσ (s,t)/dt.
Elastic scattering using an artificial confining potential.
Mitroy, J; Zhang, J Y; Varga, K
2008-09-19
The discrete energies of a scattering Hamiltonian calculated under the influence of an artificial confining potential of almost arbitrary functional form can be used to determine its phase shifts. The method exploits the result that two short-range Hamiltonians having the same energy will have the same phase shifts upon removal of the confining potential. An initial verification is performed on a simple model problem. Then the stochastic variational method is used to determine the energies of the confined e(-)-He(2)S(e) system and thus determine the low energy phase shifts.
Avalanche proton-boron fusion based on elastic nuclear collisions
NASA Astrophysics Data System (ADS)
Eliezer, Shalom; Hora, Heinrich; Korn, Georg; Nissim, Noaz; Martinez Val, Josè Maria
2016-05-01
Recent experiments done at Prague with the 600 J/0.2 ns PALS laser interacting with a layer of boron dopants in a hydrogen enriched target have produced around 109 alphas. We suggest that these unexpected very high fusion reactions of proton with 11B indicate an avalanche multiplication for the measured anomalously high nuclear reaction yields. This can be explained by elastic nuclear collisions in the broad 600 keV energy band, which is coincident with the high nuclear p-11B fusion cross section, by the way of multiplication through generation of three secondary alpha particles from a single primarily produced alpha particle.
Elastic positron-cadmium scattering at low energies
Bromley, M. W. J.; Mitroy, J.
2010-05-15
The elastic and annihilation cross sections for positron-cadmium scattering are reported up to the positronium-formation threshold (at 2.2 eV). The low-energy phase shifts for the elastic scattering of positrons from cadmium were derived from the bound and pseudostate energies of a very large basis configuration-interaction calculation of the e{sup +}-Cd system. The s-wave binding energy is estimated to be 126{+-}42 meV, with a scattering length of A{sub scat}=(14.2{+-}2.1)a{sub 0}, while the threshold annihilation parameter, Z{sub eff}, was 93.9{+-}26.5. The p-wave phase shift exhibits a weak shape resonance that results in a peak Z{sub eff} of 91{+-}17 at a collision energy of about 490{+-}50 meV.
Nuclear rainbow in elastic scattering of {sup 9}Be nuclei
Glukhov, Yu. A. Ogloblin, A. A.; Artemov, K. P.; Rudakov, V. P.
2010-01-15
A systematic investigation of the elastic scattering of the {sup 9}Be nucleus, which is among themost loosely bound stable nuclei was performed.Differential cross sections for elastic {sup 9}Be + {sup 16}O scattering were measured at a c.m. energy of 47.5 MeV (beam of 132-MeV {sup 16}O nuclei). Available data at different energy values and data for neighboring nuclei were included in our analysis. As a result, the very fact of rainbow scattering was reliably established for the first time in systems involving {sup 9}Be. In addition, the analysis in question made it possible to identify Airy minima and to determine unambiguously the nucleus-nucleus potential with a high probability.
Low-Energy Elastic Electron Scattering by Atomic Oxygen
NASA Technical Reports Server (NTRS)
Zatsarinny O.; Bartschat, K.; Tayal, S. S.
2006-01-01
The B-spline R-matrix method is employed to investigate the low-energy elastic electron scattering by atomic oxygen. Flexible non-orthogonal sets of radial functions are used to construct the target description and to represent the scattering functions. A detailed investigation regarding the dependence of the predicted partial and total cross sections on the scattering model and the accuracy of the target description is presented. The predicted angle-integrated elastic cross sections are in good agreement with experiment, whereas significant discrepancies are found in the angle-differential elastic cross sections near the forward direction. .The near-threshold results are found to strongly depend on the treatment of inner-core short-range correlation effects in the target description, as well as on a proper account of the target polarizability. A sharp increase in the elastic cross sections below 1 eV found in some earlier calculations is judged to be an artifact of an unbalanced description of correlation in the N-electron target structure and the (N+l)-electron-collision problems.
Ahmad, I.; Alvi, M.A.
1983-12-01
We propose a semiphenomenological method of analysis for intermediate energy ..cap alpha..-nucleus elastic scattering experiments and demonstrate its usefulness by analyzing available elastic ..cap alpha..-nucleus scattering data at 1.37 GeV.
Near-edge elastic photon scattering in amorphous systems
NASA Astrophysics Data System (ADS)
Hugtenburg, R. P.; England, D. W.; Bradley, D. A.
2007-10-01
The structure of valence and unoccupied electron orbitals and the neighbouring electron density distribution of atoms and ions in amorphous systems can be examined through use of resonance in the elastic photon scattering-cross-section in the vicinity of core atomic orbital energies. So-called anomalous X-ray scattering (AXS) is a mode of analysis that offers similar information to that of EXAFS but can be obtained concurrently with diffraction mode imaging. Of interest is whether the dilute-ion aqueous system provides an environment suitable for testing independent particle approximation (IPA) predictions. With the aqueous environment as the reference system for calibrating relative cross-sections, particular challenges include photons scattered by the medium being subsequently absorbed by the ion, limiting the thickness of the attenuating medium and motivating use of bright synchrotron photon sources where tunable X-rays are obtained at sub-eV resolution using a Si 111 monochromator. Measured scattering intensities and fluorescent yields were compared and shown to agree qualitatively with Monte Carlo calculations utilising amplitudes calculated from modified form-factors with anomalous scatter factors at a resolution of several eV determined from the Dirac-Slater exchange potential. Experimentally determined form-factors for pure water were used to calibrate fluorescent yield and elastic scattering intensities for measurement of the energy dependent variation of these quantities near edge and XRF imaging of the Zn concentration in wax mounted, formalin fixed, breast tumour samples. Results indicate the distribution of Zn at higher resolution than sampling dimensions used in previous studies. Shifts in the position and profile of K-edge absorption and elastic scattering features in aqeuous Zn, Zn doped sol-gel glass and Zn in tissue are shown to reflect changes in the atomic charge state and environment and offer support for the presence of non-nutrient Zn bearing
Measurement of Neutrino-Nucleon Neutral-Current Elastic Scattering Cross-section at SciBooNE
Takei, Hideyuki
2009-02-01
In this thesis, results of neutrino-nucleon neutral current (NC) elastic scattering analysis are presented. Neutrinos interact with other particles only with weak force. Measurement of cross-section for neutrino-nucleon reactions at various neutrino energy are important for the study of nucleon structure. It also provides data to be used for beam flux monitor in neutrino oscillation experiments. The cross-section for neutrino-nucleon NC elastic scattering contains the axial vector form factor G_{A}(Q^{2}) as well as electromagnetic form factors unlike electromagnetic interaction. G_{A} is propotional to strange part of nucleon spin (Δs) in Q^{2} → 0 limit. Measurement of NC elastic cross-section with smaller Q^{2} enables us to access Δs. NC elastic cross-sections of neutrino-nucleon and antineutrino-nucleon were measured earlier by E734 experiment at Brookheaven National Laboratory (BNL) in 1987. In this experiment, cross-sections were measured in Q^{2} > 0.4 GeV^{2} region. Result from this experiment was the only published data for NC elastic scattering cross-section published before our experiment. SciBooNE is an experiment for the measurement of neutrino-nucleon scattering cross-secitons using Booster Neutrino Beam (BNB) at FNAL. BNB has energy peak at 0.7 GeV. In this energy region, NC elastic scattering, charged current elastic scattering, charged current pion production, and neutral current pion production are the major reaction branches. SciBar, electromagnetic calorimeter, and Muon Range Detector are the detectors for SciBooNE. The SciBar consists of finely segmented scintillators and 14336 channels of PMTs. It has a capability to reconstruct particle track longer than 8 cm and separate proton from muons and pions using energy deposit information. Signal of NC elastic scattering is a single proton track. In vp → vp process, the recoil proton is detected. On the other hand, most of vn → vn is
{Delta} resonance contribution to two-photon exchange in electron-proton scattering
S. Kondratyuk; P. G. Blunden; W. Melnitchouk; J. A. Tjon
2005-06-01
We calculate the effects on the elastic electron-proton scattering cross section of the two-photon exchange contribution with an intermediate {Delta} resonance. The {Delta} two-photon exchange contribution is found to be smaller in magnitude than the previously evaluated nucleon contribution, with an opposite sign at backward scattering angles. The sum of the nucleon and {Delta} two-photon exchange corrections has the angular dependence compatible with both the polarization transfer and the Rosenbluth methods of measuring the nucleon electromagnetic form factors.
Electron-H P-Wave Elastic Scattering
NASA Technical Reports Server (NTRS)
Bhatia, A. K.
2004-01-01
In previous papers [Bhatia and Temkin, Phys. Rev. A 64, 032709-1 (2001), Phys. Rev. A 66, 064702 (2002)], electron-hydrogen and electron-He(+) S-wave scattering phase shifts were calculated using the optical potential approach. This method is now extended to the singlet and triplet electron-H P-wave scattering in the elastic region. Phase shifts are calculated using Hylleraas-type correlation functions with up to 220 terms. Results are rigorous lower bounds to the exact phase shifts and they are compared to phase shifts obtained from previous calculations.
Ultracold elastic H(bar sign)-He scattering
Sinha, Prabal K.; Ghosh, A. S.
2003-08-01
In view of the current interest in trapping antihydrogen H(bar sign) atoms below 1 K, the s-wave elastic-scattering parameters for the antihydrogen scattering off atomic helium target are calculated in the energy range 1x10{sup -16}-1x10{sup -2} a.u. using close-coupling models. The predicted cross section will help to simulate the evolution of a realistic mixture of He and H{sub 2} through the process involving ejection of H(bar sign) from the trap. The trend of the present results with different basis sets conclusively indicates the reliability of the predicted results.
Low-energy elastic differential scattering of He/++/ by He.
NASA Technical Reports Server (NTRS)
Lam, S. K.; Doverspike, L. D.; Champion, R. L.
1973-01-01
Experimental results are developed for the relative elastic differential scattering of He(++) by He for collision energies in the range 4 equal to or less than E equal to or less than 75 eV. In the analysis of the data, semiclassical considerations are utilized, assuming that the dynamics of the scattering is governed solely by the B and E states of He2(++). It is shown that existing ab initio calculations for the intermolecular potentials predict differential cross sections which are not in particularly good agreement with the experimental data.
Measurement of neutrino flux from neutrino-electron elastic scattering
NASA Astrophysics Data System (ADS)
Park, J.; Aliaga, L.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Cai, T.; Carneiro, M. F.; Christy, M. E.; Chvojka, J.; da Motta, H.; Dytman, S. A.; Díaz, G. A.; Eberly, B.; Felix, J.; Fields, L.; Fine, R.; Gago, A. M.; Galindo, R.; Ghosh, A.; Golan, T.; Gran, R.; Harris, D. A.; Higuera, A.; Kleykamp, J.; Kordosky, M.; Le, T.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; Martinez Caicedo, D. A.; McFarland, K. S.; McGivern, C. L.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Mousseau, J.; Naples, D.; Nelson, J. K.; Norrick, A.; Nuruzzaman; Osta, J.; Paolone, V.; Patrick, C. E.; Perdue, G. N.; Rakotondravohitra, L.; Ramirez, M. A.; Ray, H.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Solano Salinas, C. J.; Tagg, N.; Tice, B. G.; Valencia, E.; Walton, T.; Wolcott, J.; Wospakrik, M.; Zavala, G.; Zhang, D.; Miner ν A Collaboration
2016-06-01
Muon-neutrino elastic scattering on electrons is an observable neutrino process whose cross section is precisely known. Consequently a measurement of this process in an accelerator-based νμ beam can improve the knowledge of the absolute neutrino flux impinging upon the detector; typically this knowledge is limited to ˜10 % due to uncertainties in hadron production and focusing. We have isolated a sample of 135 ±17 neutrino-electron elastic scattering candidates in the segmented scintillator detector of MINERvA, after subtracting backgrounds and correcting for efficiency. We show how this sample can be used to reduce the total uncertainty on the NuMI νμ flux from 9% to 6%. Our measurement provides a flux constraint that is useful to other experiments using the NuMI beam, and this technique is applicable to future neutrino beams operating at multi-GeV energies.
Measurement of neutrino flux from neutrino-electron elastic scattering
Park, J.; Aliaga, L.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Cai, T.; et al
2016-06-10
In muon-neutrino elastic scattering on electrons is an observable neutrino process whose cross section is precisely known. Consequently a measurement of this process in an accelerator-based νμ beam can improve the knowledge of the absolute neutrino flux impinging upon the detector; typically this knowledge is limited to ~10% due to uncertainties in hadron production and focusing. We also isolated a sample of 135±17 neutrino-electron elastic scattering candidates in the segmented scintillator detector of MINERvA, after subtracting backgrounds and correcting for efficiency. We show how this sample can be used to reduce the total uncertainty on the NuMI νμ flux frommore » 9% to 6%. Finally, our measurement provides a flux constraint that is useful to other experiments using the NuMI beam, and this technique is applicable to future neutrino beams operating at multi-GeV energies.« less
Scatter of elastic waves by a thin flat elliptical inhomogeneity
NASA Technical Reports Server (NTRS)
Fu, L. S.
1983-01-01
Elastodynamic fields of a single, flat, elliptical inhomogeneity embedded in an infinite elastic medium subjected to plane time harmonic waves are studied. Scattered displacement amplitudes and stress intensities are obtained in series form for an incident wave in an arbitrary direction. The cases of a penny shaped crack and an elliptical crack are given as examples. The analysis is valid for alpha a up to about two, where alpha is longitudinal wave number and a is a typical geometric parameter.
Practical correction procedures for elastic electron scattering effects in ARXPS
NASA Astrophysics Data System (ADS)
Lassen, T. S.; Tougaard, S.; Jablonski, A.
2001-06-01
Angle-resolved XPS and AES (ARXPS and ARAES) are widely used for determination of the in-depth distribution of elements in the surface region of solids. It is well known that elastic electron scattering has a significant effect on the intensity as a function of emission angle and that this has a great influence on the determined overlayer thicknesses by this method. However the applied procedures for ARXPS and ARAES generally neglect this because no simple and practical procedure for correction has been available. However recently, new algorithms have been suggested. In this paper, we have studied the efficiency of these algorithms to correct for elastic scattering effects in the interpretation of ARXPS and ARAES. This is done by first calculating electron distributions by Monte Carlo simulations for well-defined overlayer/substrate systems and then to apply the different algorithms. We have found that an analytical formula based on a solution of the Boltzmann transport equation provides a good account for elastic scattering effects. However this procedure is computationally very slow and the underlying algorithm is complicated. Another much simpler algorithm, proposed by Nefedov and coworkers, was also tested. Three different ways of handling the scattering parameters within this model were tested and it was found that this algorithm also gives a good description for elastic scattering effects provided that it is slightly modified so that it takes into account the differences in the transport properties of the substrate and the overlayer. This procedure is fairly simple and is described in detail. The model gives a much more accurate description compared to the traditional straight-line approximation (SLA). However it is also found that when attenuation lengths instead of inelastic mean free paths are used in the simple SLA formalism, the effects of elastic scattering are also reasonably well accounted for. Specifically, from a systematic study of several
N13+p elastic resonance scattering via a thick-target method
NASA Astrophysics Data System (ADS)
Wang, Y. B.; Wang, B. X.; Qin, X.; Bai, X. X.; Guo, B.; Jiang, C.; Li, Y. J.; Li, Z. H.; Lian, G.; Su, J.; Zeng, S.; Liu, W. P.
2008-04-01
The N13+p elastic resonance scattering has been studied in inverse kinematics via a thick-target method. A N13 secondary beam of 47.8±1.5 MeV produced by the H2(C12,N13)n reaction was used to bombard a 9.33 mg/cm2 (CH2)n target. The recoil protons were detected by a ΔE-E silicon counter telescope at θlab=15°. The performance of the setup was checked by C12+p elastic resonance scattering with the same (CH2)n target. The excitation function for the N13(p,p) elastic scattering was obtained in the energy interval of Ec.m.~0.5-3.2 MeV and was analyzed by using a multilevel R-matrix code MULTI7. Several low-lying excited states in O14 were surveyed. Our results confirm a very recent 2- assignment to the 6.8 MeV level and agree with the observation of a new 0- level at 5.7 MeV with a width of 400(45) keV.
Inverse elastic surface scattering with near-field data
NASA Astrophysics Data System (ADS)
Li, Peijun; Wang, Yuliang; Zhao, Yue
2015-03-01
Consider the scattering of a time-harmonic plane wave by a one-dimensional periodic surface. A novel computational method is proposed for solving the inverse elastic surface scattering problem by using the near-field data. Above the surface, the space is filled with a homogeneous and isotropic elastic medium, while the space below the surface is assumed to be elastically rigid. Given an incident field, the inverse problem is to reconstruct the surface from the displacement of the wave field at a horizontal line above the surface. This paper is a nontrivial extension of the authors’ recent work on near-field imaging of the Helmholtz equation and the Maxwell equation to the more complicated Navier equation due to coexistence of the compressional and shear waves that propagate at different speed. Based on the Helmholtz decomposition, the wave field is decomposed into its compressional and shear parts by using two scalar potential functions. The transformed field expansion is then applied to each component and a coupled recurrence relation is obtained for their power series expansions. By solving the coupled system in the frequency domain, simple and explicit reconstruction formulas are derived for two types of measurement data. The method requires only a single illumination with a fixed frequency and incident angle. Numerical experiments show that it is simple, effective, and efficient to reconstruct the scattering surfaces with subwavelength resolution. The research was supported in part by the NSF grant DMS-1151308.
Deconstruction and elastic {pi}{pi} scattering in Higgsless models
Chivukula, R. Sekhar; Simmons, Elizabeth H.; He, Hong-Jian; Kurachi, Masafumi; Tanabashi, Masaharu
2007-02-01
We study elastic pion-pion scattering in global linear moose models and apply the results to a variety of Higgsless models in flat and anti-de Sitter (AdS) space using the equivalence theorem. In order to connect the global moose to Higgsless models, we first introduce a block-spin transformation which corresponds, in the continuum, to the freedom to perform coordinate transformations in the Higgsless model. We show that it is possible to make an 'f-flat' deconstruction in which all of the f-constants f{sub j} of the linear moose model are identical; the phenomenologically relevant f-flat models are those in which the coupling constants of the groups at either end of the moose are small--corresponding to the global linear moose. In studying pion-pion scattering, we derive various sum rules, including one analogous to the Kawarabayashi-Suzuki-Riazuddin-Fayyazuddin (KSRF) relation, and use them in evaluating the low-energy and high-energy forms of the leading elastic partial-wave scattering amplitudes. We obtain elastic unitarity bounds as a function of the mass of the lightest KK mode and discuss their physical significance.
Deconstruction and elastic ππ scattering in Higgsless models
NASA Astrophysics Data System (ADS)
Chivukula, R. Sekhar; Simmons, Elizabeth H.; He, Hong-Jian; Kurachi, Masafumi; Tanabashi, Masaharu
2007-02-01
We study elastic pion-pion scattering in global linear moose models and apply the results to a variety of Higgsless models in flat and anti-de Sitter (AdS) space using the equivalence theorem. In order to connect the global moose to Higgsless models, we first introduce a block-spin transformation which corresponds, in the continuum, to the freedom to perform coordinate transformations in the Higgsless model. We show that it is possible to make an “f-flat” deconstruction in which all of the f-constants fj of the linear moose model are identical; the phenomenologically relevant f-flat models are those in which the coupling constants of the groups at either end of the moose are small—corresponding to the global linear moose. In studying pion-pion scattering, we derive various sum rules, including one analogous to the Kawarabayashi-Suzuki-Riazuddin-Fayyazuddin (KSRF) relation, and use them in evaluating the low-energy and high-energy forms of the leading elastic partial-wave scattering amplitudes. We obtain elastic unitarity bounds as a function of the mass of the lightest KK mode and discuss their physical significance.
Proton-proton Scattering Above 3 GeV/c
A. Sibirtsev, J. Haidenbauer, H.-W. Hammer S. Krewald ,Ulf-G. Meissner
2010-01-01
A large set of data on proton-proton differential cross sections, analyzing powers and the double-polarization parameter A{sub NN} is analyzed employing the Regge formalism. We find that the data available at proton beam momenta from 3 GeV/c to 50 GeV/c exhibit features that are very well in line with the general characteristics of Regge phenomenology and can be described with a model that includes the {rho}, {omega}, f{sub 2}, and a{sub 2} trajectories and single-Pomeron exchange. Additional data, specifically for spin-dependent observables at forward angles, would be very helpful for testing and refining our Regge model.
Acoustic and elastic multiple scattering and radiation from cylindrical structures
NASA Astrophysics Data System (ADS)
Amirkulova, Feruza Abdukadirovna
Multiple scattering (MS) and radiation of waves by a system of scatterers is of great theoretical and practical importance and is required in a wide variety of physical contexts such as the implementation of "invisibility" cloaks, the effective parameter characterization, and the fabrication of dynamically tunable structures, etc. The dissertation develops fast, rapidly convergent iterative techniques to expedite the solution of MS problems. The formulation of MS problems reduces to a system of linear algebraic equations using Graf's theorem and separation of variables. The iterative techniques are developed using Neumann expansion and Block Toeplitz structure of the linear system; they are very general, and suitable for parallel computations and a large number of MS problems, i.e. acoustic, elastic, electromagnetic, etc., and used for the first time to solve MS problems. The theory is implemented in Matlab and FORTRAN, and the theoretical predictions are compared to computations obtained by COMSOL. To formulate the MS problem, the transition matrix is obtained by analyzing an acoustic and an elastic single scattering of incident waves by elastic isotropic and anisotropic solids. The mathematical model of wave scattering from multilayered cylindrical and spherical structures is developed by means of an exact solution of dynamic 3D elasticity theory. The recursive impedance matrix algorithm is derived for radially heterogeneous anisotropic solids. An explicit method for finding the impedance in piecewise uniform, transverse-isotropic material is proposed; the solution is compared to elasticity theory solutions involving Buchwald potentials. Furthermore, active exterior cloaking devices are modeled for acoustic and elastic media using multipole sources. A cloaking device can render an object invisible to some incident waves as seen by some external observer. The active cloak is generated by a discrete set of multipole sources that destructively interfere with an
Elastic scattering measurements for {sup 7}Be+{sup 27}Al system at RIBRAS facility
Morcelle, V.; Lichtenthaeler, R.; Morais, M. C.; Lepine-Szily, A.; Guimaraes, V.; Faria, P. N. de; Gasques, L.; Pires, K. C. C.; Condori, R. P.; Gomes, P. R. S.; Lubian, J.; Mendes, D. R. Jr.; Barioni, A.; Shorto, J. M. B.; Zamora, J. C.
2013-05-06
Elastic scattering angular distribution measurements of {sup 7}Be+{sup 27}Al system were performed at the laboratory energy of 15.6 MeV. The {sup 7}Be secondary beam was produced by the proton transfer reaction {sup 3}He({sup 6}Li,{sup 7}Be) and impinged on {sup 27}Al and {sup 197}Au targets, using the Radioactive Ion Beam (RIB) facility, RIBRAS. The elastic angular distribution was obtained within the angular range of 15{sup 0} - 80{sup 0} at the center of mass frame. Optical model calculations have been performed using the Woods- Saxon form factors and the Sao Paulo potential to fit the experimental data. The total reaction cross section was derived.
A Double Scattering Analytical Model For Elastic Recoil Detection Analysis
Barradas, N. P.; Lorenz, K.; Alves, E.; Darakchieva, V.
2011-06-01
We present an analytical model for calculation of double scattering in elastic recoil detection measurements. Only events involving the beam particle and the recoil are considered, i.e. 1) an ion scatters off a target element and then produces a recoil, and 2) an ion produces a recoil which then scatters off a target element. Events involving intermediate recoils are not considered, i.e. when the primary ion produces a recoil which then produces a second recoil. If the recoil element is also present in the stopping foil, recoil events in the stopping foil are also calculated. We included the model in the standard code for IBA data analysis NDF, and applied it to the measurement of hydrogen in Si.
Elastic wave scattering to characterize heterogeneities in the borehole environment
NASA Astrophysics Data System (ADS)
Tang, Xiao-Ming; Li, Zhen; Hei, Chuang; Su, Yuan-Da
2016-04-01
Scattering due to small-scale heterogeneities in the rock formation surrounding a wellbore can significantly change the acoustic waveform from a logging measurement which in turn can be used to characterize the formation heterogeneities. This study simulates the elastic heterogeneity scattering in monopole and dipole acoustic logging and analyse the resulting effects on the waveforms. The results show that significant coda waves are generated in both monopole and dipole waveforms and the dipole coda is dominated by S-to-S scattering, which can be effectively utilized to diagnose the heterogeneity in the rock formation. The coda wave modelling and analysis were used to characterize dipole acoustic data logged before and after fracturing a reservoir interval, with significant coda wave in the after-fracturing data indicating fracturing-induced heterogeneous property change in the rock volume surrounding the borehole.
Contributions From yZ Box Diagrams to Parity Violating Elastic e-p Scattering
Benjamin Rislow, Carl Carlson
2011-06-01
Parity-violating (PV) elastic electron-proton scattering measures Q-weak for the proton, Q{sub W}{sup p}. To extract Q{sub W}{sup p} from data, all radiative corrections must be well-known. Recently, disagreement on the {gamma}Z box contribution to Q{sub W}{sup p} has prompted the need for further analysis of this term. Here, we support one choice of a debated factor, go beyond the previously assumed equality of electromagnetic and {gamma}Z structure functions, and find an analytic result for one of the {gamma}Z box integrals. Our numerical evaluation of the {gamma}Z box is in agreement within errors with previous reports, albeit somewhat larger in central value, and is within the uncertainty requirements of current experiments.
Proton beam scattering system optimization for clinical and research applications
Wroe, A. J.; Schulte, R. W.; Slater, J. D.; Barnes, S.; McAuley, G.; Slater, J. M.
2013-04-15
Purpose: To develop and test a method for optimizing and constructing a dual scattering system in passively scattered proton therapy. Methods: A beam optics optimization algorithm was developed to optimize the thickness of the first scatterer (S1) and the profile (of both the high-Z material and Lexan) of the second scatterer (S2) to deliver a proton beam matching a given set of parameters, including field diameter, fluence, flatness, and symmetry. A new manufacturing process was also tested that allows the contoured second scattering foil to be created much more economically and quickly using Cerrobend casting. Two application-specific scattering systems were developed and tested using both experimental and Monte Carlo techniques to validate the optimization process described. Results: A scattering system was optimized and constructed to deliver large uniform irradiations of radiobiology samples at low dose rates. This system was successfully built and tested using film and ionization chambers. The system delivered a uniform radiation field of 50 cm diameter (to a dose of {+-}7% of the central axis) while the depth dose profile could be tuned to match the specifications of the particular investigator using modulator wheels and range shifters. A second scattering system for intermediate field size (4 cm < diameter < 10 cm) stereotactic radiosurgery and radiation therapy (SRS and SRT) treatments was also developed and tested using GEANT4. This system improved beam efficiency by over 70% compared with existing scattering systems while maintaining field flatness and depth dose profile. In both cases the proton range uniformity across the radiation field was maintained, further indicating the accuracy of the energy loss formalism in the optimization algorithm. Conclusions: The methods described allow for rapid prototyping of scattering foils to meet the demands of both research and clinical beam delivery applications in proton therapy.
A Microscopic Optical Potential Approach to {sup 6,8}He+p Elastic Scattering
Lukyanov, V. K.; Zemlyanaya, E. V.; Lukyanov, K. V.; Kadrev, D. N.; Antonov, A. N.; Gaidarov, M. K.; Massen, S. E.
2009-08-26
A microscopic approach to calculate the optical potential (OP) with the real part obtained by a folding procedure and with the imaginary part inherent in the high-energy approximation (HEA) is applied to study the {sup 6,8}He+p elastic scattering data at energies of tens of MeV/N. The OP's and the cross sections are calculated using different models for the neutron and proton densities of {sup 6,8}He. The role of the spin-orbit (SO) potential and effects of the energy and density dependence of the effective NN forces are studied. Comparison of the calculations with the available experimental data on the elastic scattering differential cross sections at beam energies <100 MeV/N is performed and conclusions on the role of the aforesaid effects are made. It is shown that the present approach, which uses only parameters that renormalize the depths of the OP, can be applied along with other methods like that from the microscopic g-matrix description of the complex proton optical potential.
Inclusive proton spectra and total reaction cross sections for proton-nucleus scattering at 800 MeV
McGill, J.A.
1981-08-01
Current applications of multiple scattering theory to describe the elastic scattering of medium energy protons from nuclei have been shown to be quite successful in reproducing the experimental cross sections. These calculations use the impulse approximation, wherein the scattering from individual nucleons in the nucleus is described by the scattering amplitude for a free nucleon. Such an approximation restricts the inelastic channels to those initiated by nucleon-nucleon scattering. As a first step in determining the nature of p + nucleus scattering at 800 MeV, both total reaction cross sections and (p,p') inclusive cross sections were measured and compared to the free p + p cross sections for hydrogen, deuterium, calcium 40, carbon 12, and lead 208. It is concluded that as much as 85% of all reactions in a nucleus proceed from interactions with a single nucleon in the nucleus, and that the impulse approximation is a good starting point for a microscopic description of p + nucleus interactions at 800 MeV.
Elastic scattering of polarised deuterons from 16O at 200, 400 and 700 MeV
NASA Astrophysics Data System (ADS)
van Sen, Nguyen; Yanlin, Ye; Arvieux, J.; Gaillard, G.; Bonin, B.; Boudard, A.; Bruge, G.; Lugol, J. C.; Hasegawa, T.; Soga, F.; Antonuk, L. E.; Cameron, J. M.; Lam, S. T.; Neilson, G. C.; Roy, G.; Sheppard, D. M.; Babinet, R.
1987-03-01
Angular distributions of cross section, and Ay and Ayy analysing powers were measured for polarised deuteron elastic scattering from 16O at 200, 400 and 700 MeV. The data at 200 MeV bear evidence of the nuclear rainbow phenomenon while those at 400 and 700 MeV are reminiscent of the proton scattering results at equivalent energies. The data were analysed in terms of the optical model. The real central potential shape changes from an attractive Woods-Saxon form at 200 MeV to a wine-bottle-bottom form with a repulsive interior at 700 MeV. The total reaction cross sections deduced display a clear nuclear transparency effect in the present energy domain in agreement with predictions from the Glauber theory optical limit. Comparison with previous results for 40Ca and 58Ni targets is made.
Elastic and Inelastic Scattering of Neutrons using a CLYC array
NASA Astrophysics Data System (ADS)
Brown, Tristan; Doucet, E.; Chowdhury, P.; Lister, C. J.; Wilson, G. L.; Devlin, M.; Mosby, S.
2015-10-01
CLYC scintillators, which have dual neutron and gamma response, have recently ushered in the possibility of fast neutron spectroscopy without time-of-flight (TOF). A 16-element array of 1'' x 1'' 6Li-depleted CLYC crystals, where pulse-shape-discrimination is achieved via digital pulse processing, has been commissioned at UMass Lowell. In an experiment at LANSCE, high energy neutrons were used to bombard 56Fe and 238U targets, in order to measure elastic and inelastic neutron scattering cross sections as a function of energy and angle with the array. The array is placed very close to the targets for enhanced geometrical solid angles for scattered neutrons compared to standard neutron-TOF measurements. A pulse-height spectrum of scattered neutrons in the detectors is compared to the energy of the incident neutrons, which is measured via the TOF of the pulsed neutrons from the source to the detectors. Recoil corrections are necessary to combine the energy spectra from all the detectors to obtain angle-integrated elastic and inelastic cross-sections. The detection techniques, analysis procedures and results will be presented. Supported by NNSA-SSAA program through DOE Grant DE-NA00013008.
Studies of toxic aerosols via elastic and inelastic light scattering
Foss, W.; Li, W.; Allen, T.M.; Blair, D.S.; Davis, E.J. )
1993-02-01
Evaporation rates and chemical characteristics of potentially toxic aerosols have been determined by elastic and inelastic light-scattering measurements. The aerosol systems examined were a commercial catalyst consisting of a mixture of stannous octanoate (SNO) and 2-ethylhexanoic acid (EHA) and droplets emitted from open tanks of chromic acid solutions used for anodizing aluminum. The heavy metals contained in these aerosols represent a danger to the workplace if such materials are inhaled. Nanogram amounts of the solutions were studied by suspending single microdroplets in electrodynamic balances in a flow of air to measure evaporation rates and to obtain Raman spectra. Elastic scattering data include phase functions and morphological resonance spectra from which droplet sizes are determined. The inelastic light-scattering data or Raman spectra provide molecular vibrational bond information. It was found that EHA spectra agree with bulk data in the literature, and that SNO Raman spectra, which are not available in the literature, are consistent with infrared spectra for bulk SNO. At room temperature the vapor pressure of SNO is on the order of 0.01 Pa while that of EHA is on the order of 0.1 Pa. Raman data for the residue of evaporated chromic acid solutions show the presence of chromium oxides (Cr[sup 6+] compounds), surfactants, and bound (nonvolatile) water. 31 refs., 14 figs.
Elastic and inelastic scattering of neutrons on 238U nucleus
NASA Astrophysics Data System (ADS)
Capote, R.; Trkov, A.; Sin, M.; Herman, M. W.; Soukhovitskiĩ, E. Sh.
2014-04-01
Advanced modelling of neutron induced reactions on the 238U nucleus is aimed at improving our knowledge of neutron scattering. Capture and fission channels are well constrained by available experimental data and neutron standard evaluation. A focus of this contribution is on elastic and inelastic scattering cross sections. The employed nuclear reaction model includes - a new rotational-vibrational dispersive optical model potential coupling the low-lying collective bands of vibrational character observed in even-even actinides; - the Engelbrecht-Weidenmüller transformation allowing for inclusion of compound-direct interference effects; - and a multi-humped fission barrier with absorption in the secondary well described within the optical model for fission. Impact of the advanced modelling on elastic and inelastic scattering cross sections including angular distributions and emission spectra is assessed both by comparison with selected microscopic experimental data and integral criticality benchmarks including measured reaction rates (e.g. JEMIMA, FLAPTOP and BIG TEN). Benchmark calculations provided feedback to improve the reaction modelling. Improvement of existing libraries will be discussed.
Overview of single-cell elastic light scattering techniques.
Kinnunen, Matti; Karmenyan, Artashes
2015-05-01
We present and discuss several modern optical methods based on elastic light scattering (ELS), along with their technical features and applications in biomedicine and life sciences. In particular, we review some ELS experiments at the single-cell level and explore new directions of applications. Due to recent developments in experimental systems (as shown in the literature), ELS lends itself to useful applications in the life sciences. Of the developed methods, we cover elastic scattering spectroscopy, optical tweezer-assisted measurement, goniometers, Fourier transform light scattering (FTLS), and microscopic methods. FTLS significantly extends the potential analysis of single cells by allowing monitoring of dynamical changes at the single-cell level. The main aim of our review is to demonstrate developments in the experimental investigation of ELS in single cells including issues related to theoretical “representations” and modeling of biological systems (cells, cellular systems, tissues, and so on). Goniometric measurements of ELS from optically trapped single cells are shown and the importance of the experimental verification of theoretical models of ELS in the context of biomedical applications is discussed.
Karlsson, Maths
2015-01-01
This article is concerned with the use of quasielastic neutron scattering as a technique for investigation of the dynamical properties of proton conducting oxides. Currently, the main interest in these materials comes from their promise as electrolytes in future electrochemical devices and particularly through their use as electrolytes in next-generation, intermediate-temperature, fuel cells. However, the realization of such devices depends critically on the development of new, more highly proton conducting oxides. Such a development depends on increasing the current understanding of proton conduction in oxides and for this purpose quasielastic neutron scattering is an important mean. The aim of this article is to introduce the non-specialist reader to the basic principles of quasielastic neutron scattering, its advantages and disadvantages, to summarize the work that has been done on proton conducting oxides using this technique, as well as to discuss future opportunities within this field of research.
Polarisation Transfer in Proton Compton Scattering at High Momentum Transfer
Hamilton, David Jonathan
2004-01-01
The Jefferson Lab Hall A experiment E99-114 comprised a series of measurements to explore proton Compton scattering at high momentum transfer. For the first time, the polarisation transfer observables in the p ($\\vec{γ}$, γ' \\vec{p}$) reaction were measured in the GeV energy range, where it is believed that quark-gluon degrees of freedom begin to dominate. The experiment utilised a circularly polarised photon beam incident on a liquid hydrogen target, with the scattered photon and recoil proton detected in a lead-glass calorimeter and a magnetic spectrometer, respectively.
Polarization Transfer in Proton Compton Scattering at High Momentum Transfer
Hamilton, D.J.; Annand, J.R.M.; Mamyan, V.H.; Aniol, K.A.; Margaziotis, D.J.; Bertin, P.Y.; Camsonne, A.; Laveissiere, G.; Bosted, P.; Paschke, K.; Calarco, J.R.; Chang, G.C.; Horn, T.; Savvinov, N.; Chang, T.-H.; Danagoulian, A.; Nathan, A.M.; Roedelbronn, M.; Chen, J.-P.
2005-06-24
Compton scattering from the proton was investigated at s=6.9 GeV{sup 2} and t=-4.0 GeV{sup 2} via polarization transfer from circularly polarized incident photons. The longitudinal and transverse components of the recoil proton polarization were measured. The results are in disagreement with a prediction of perturbative QCD based on a two-gluon exchange mechanism, but agree well with a prediction based on a reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton.
A method for calculating proton-nucleus elastic cross-sections
NASA Technical Reports Server (NTRS)
Tripathi, R. K.; Wilson, J. W.; Cucinotta, F. A.
2002-01-01
Recently [Nucl. Instr. and Meth. B 145 (1998) 277; Extraction of in-medium nucleon-nucleon amplitude from experiment, NASA-TP, 1998], we developed a method of extracting nucleon-nucleon (N-N) cross-sections in the medium directly from experiment. The in-medium N-N cross-sections form the basic ingredients of several heavy-ion scattering approaches including the coupled-channel approach developed at the NASA Langley Research Center. We investigated [Proton-nucleus total cross-sections in coupled-channel approach, NASA/TP, 2000; Nucl. Instr. and Meth. B 173-174 (2001) 391] the ratio of real to imaginary part of the two body scattering amplitude in the medium. These ratios are used in combination with the in-medium N-N cross-sections to calculate proton-nucleus elastic cross-sections. The agreement is excellent with the available experimental data. These cross-sections are needed for the radiation risk assessment of space missions. c2002 Elsevier Science B.V. All rights reserved.
Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data
Adikaram, D.; Rimal, D.; Weinstein, L. B.; Raue, B.; Khetarpal, P.; Bennett, R.; Arrington, J.; Brooks, W.; Adhikari, K.; Afanasev, A.; et al
2015-02-10
There is a significant discrepancy between the values of the proton electric form factor, GpE, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of GpE from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (epsilon) and momentummore » transfer (Q2) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ε at Q2=1.45 GeV2. This measurement is consistent with the size of the form factor discrepancy at Q2≈1.75 GeV2 and with hadronic calculations including nucleon and Delta intermediate states, which have been shown to resolve the discrepancy up to 2-3 GeV2.« less
Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data
Adikaram, D.; Rimal, D.; Weinstein, L. B.; Raue, B.; Khetarpal, P.; Bennett, R.; Arrington, J.; Brooks, W.; Adhikari, K.; Afanasev, A.; Amaryan, M.; Anderson, M.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A.; Bono, J.; Boiarinov, S.; Briscoe, W.; Burkert, V.; Carman, D.; Careccia, S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J.; Fradi, A.; Garillon, B.; Gilfoyle, G.; Giovanetti, K.; Girod, F.; Goetz, J.; Gohn, W.; Golovatch, E.; Gothe, R.; Griffioen, K.; Guegan, B.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S.; Hyde, C. E.; Ilieva, Y.; Ireland, D.; Ishkhanov, B.; Jenkins, D.; Jiang, H.; Jo, H.; Joo, K.; Joosten, S.; Kalantarians, N.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F.; Koirala, S.; Kubarovsky, V.; Kuhn, S.; Livingston, K.; Lu, H.; MacGregor, I.; Markov, N.; Mattione, P.; Mayer, M.; McKinnon, B.; Mestayer, M.; Meyer, C.; Mirazita, M.; Mokeev, V.; Montgomery, R.; Moody, C.; Moutarde, H.; Movsisyan, A.; Camacho, C. Munoz; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A.; Park, K.; Pasyuk, E.; Pisano, S.; Pogorelko, O.; Price, J.; Procureur, S.; Prok, Y.; Protopopescu, D.; Puckett, A.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabati, F.; Salgado, C.; Schott, D.; Schumacher, R.; Seder, E.; Sharabian, Y.; Simonyan, A.; Skorodumina, I.; Smith, E.; Smith, G.; Sober, D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tian, Ye; Trivedi, A.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N.; Watts, D.; Wei, X.; Wood, M.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z.; Zonta, I.
2015-02-10
There is a significant discrepancy between the values of the proton electric form factor, GpE, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of GpE from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (epsilon) and momentum transfer (Q2) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ε at Q2=1.45 GeV2. This measurement is consistent with the size of the form factor discrepancy at Q2≈1.75 GeV2 and with hadronic calculations including nucleon and Delta intermediate states, which have been shown to resolve the discrepancy up to 2-3 GeV2.
Towards a resolution of the proton form factor problem: new electron and positron scattering data.
Adikaram, D; Rimal, D; Weinstein, L B; Raue, B; Khetarpal, P; Bennett, R P; Arrington, J; Brooks, W K; Adhikari, K P; Afanasev, A V; Amaryan, M J; Anderson, M D; Anefalos Pereira, S; Avakian, H; Ball, J; Battaglieri, M; Bedlinskiy, I; Biselli, A S; Bono, J; Boiarinov, S; Briscoe, W J; Burkert, V D; Carman, D S; Careccia, S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Contalbrigo, M; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Dodge, G E; Dupre, R; Egiyan, H; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fegan, S; Filippi, A; Fleming, J A; Fradi, A; Garillon, B; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Hanretty, C; Harrison, N; Hattawy, M; Hicks, K; Holtrop, M; Hughes, S M; Hyde, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Jenkins, D; Jiang, H; Jo, H S; Joo, K; Joosten, S; Kalantarians, N; Keller, D; Khandaker, M; Kim, A; Kim, W; Klein, A; Klein, F J; Koirala, S; Kubarovsky, V; Kuhn, S E; Livingston, K; Lu, H Y; MacGregor, I J D; Markov, N; Mattione, P; Mayer, M; McKinnon, B; Mestayer, M D; Meyer, C A; Mirazita, M; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Camacho, C Munoz; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Peña, C; Pisano, S; Pogorelko, O; Price, J W; Procureur, S; Prok, Y; Protopopescu, D; Puckett, A J R; Ripani, M; Rizzo, A; Rosner, G; Rossi, P; Roy, P; Sabatié, F; Salgado, C; Schott, D; Schumacher, R A; Seder, E; Sharabian, Y G; Simonyan, A; Skorodumina, I; Smith, E S; Smith, G D; Sober, D I; Sokhan, D; Sparveris, N; Stepanyan, S; Stoler, P; Strauch, S; Sytnik, V; Taiuti, M; Tian, Ye; Trivedi, A; Ungaro, M; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Wood, M H; Zachariou, N; Zana, L; Zhang, J; Zhao, Z W; Zonta, I
2015-02-13
There is a significant discrepancy between the values of the proton electric form factor, G(E)(p), extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of G(E)(p) from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (ϵ) and momentum transfer (Q(2)) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ϵ at Q(2)=1.45 GeV(2). This measurement is consistent with the size of the form factor discrepancy at Q(2)≈1.75 GeV(2) and with hadronic calculations including nucleon and Δ intermediate states, which have been shown to resolve the discrepancy up to 2-3 GeV(2).
Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data
Adikaram, D.; Rimal, D.; Weinstein, L. B.; Raue, B.; Khetarpal, P.; Bennett, R. P.; Arrington, J.; Brooks, W. K.; Adhikari, K. P.; Afanasev, A. V.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Hafidi, K.; Moody, C. I.
2015-02-10
There is a significant discrepancy between the values of the proton electric form factor, G(E)(p), extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of G(E)(p). from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (epsilon) and momentum transfer (Q(2)) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing epsilon at Q(2) = 1.45 GeV2. This measurement is consistent with the size of the form factor discrepancy at Q(2) approximate to 1.75 GeV2 and with hadronic calculations including nucleon and Delta intermediate states, which have been shown to resolve the discrepancy up to 2-3 GeV2.
Elastic scattering of Beryllium isotopes near the Coulomb barrier
Di Pietro, A.; Figuera, P.; Amorini, F.; Fisichella, M.; Lattuada, M.; Musumarra, A.; Pellegriti, M. G.; Randisi, G.; Rizzo, F.; Santonocito, D.; Scalia, G.; Scuderi, V.; Strano, E.; Torresi, D.; Papa, M.; Acosta, L.; Martel, I.; Perez-Bernal, F.; Borge, M. J. G.; Tengblad, O.
2011-10-28
In this contribution, results of experiments performed with the three Beryllium isotopes {sup 9,10,11}Be on a medium mass {sup 64}Zn target, at a center of mass energy of {approx_equal}1.4 the Coulomb barrier, will be discussed. Elastic scattering angular distributions have been measured for the {sup 9,10}Be reactions. In the {sup 11}Be case the quasielastic scattering angular distribution was obtained. In the halo nucleus case, the angular distribution exhibit a non-Fresnel-type pattern with a strong damping of the Coulomb-nuclear interference peak. Moreover, it is found that the total reaction cross-section for the halo nucleus induced collision is more than double the ones extracted in the collisions induced by the non-halo Beryllium isotopes. A large contribution to the total-reaction cross-section in the {sup 11}Be case could be attributed to transfer and/or break-up events.
cap alpha. /sup 4/He elastic scattering at high energies
Usmani, A.A.; Ahmad, I.; Usmani, Q.N.
1989-03-01
Differential cross sections for ..cap alpha.. /sup 4/He elastic scattering have been calculated at incident ..cap alpha..-particle momenta of 4.32, 5.07, and 7.0 GeV/c within the framework of Glauber multiple scattering theory. The full Glauber amplitude has been calculated using the Monte Carlo method for evaluating multidimensional integrals. We found that, in general, the more realistic double-Gaussian model for the density brings theory closer to experiment as compared to the generally used single-Gaussian model in some momentum transfer regions. Our results with the double-Gaussian model and an acceptable set of NN parameters are in fairly good agreement with the experimental data at 4.32 and 5.07 GeV/c.
Hybrid Modeling of Elastic Wave Scattering in a Welded Cylinder
NASA Astrophysics Data System (ADS)
Mahmoud, A.; Shah, A. H.; Popplewell, N.
2003-03-01
In the present study, a 3D hybrid method, which couples the finite element region with guided elastic wave modes, is formulated to investigate the scattering by a non-axisymmetric crack in a welded steel pipe. The algorithm is implemented on a parallel computing platform. Implementation is facilitated by the dynamic memory allocation capabilities of Fortran 90™ and the parallel processing directives of OpenMp™. The algorithm is validated against available numerical results. The agreement with a previous 2D hybrid model is excellent. Novel results are presented for the scattering of the first longitudinal mode from different non-axisymmetric cracks. The trend of the new results is consistent with the previous findings for the axisymmetric case. The developed model has potential application in ultrasonic nondestructive evaluation of welded steel pipes.
David Armstrong; Francois Arvieux; Razmik Asaturyan; Todd Averett; Stephanie Bailey; Guillaume Batigne; Douglas Beck; Elizabeth Beise; Jay Benesch; Louis Bimbot; James Birchall; Angela Biselli; Peter Bosted; Elodie Boukobza; Herbert Breuer; Roger Carlini; R. Carr; Nicholas Chant; Yu-Chiu Chao; Swapan Chattopadhyay; Russell Clark; Silviu Covrig; Anthony Cowley; Daniel Dale; C. Davis; Willie Falk; John Finn; Tony Forest; Gregg Franklin; Christophe Furget; David Gaskell; Joseph Grames; Keith Griffioen; Klaus Grimm; Benoit Guillon; Hayko Guler; Lars Hannelius; R. Hasty; A. Hawthorne Allen; Tanja Horn; Kathleen Johnston; Mark Jones; Peter Kammel; Reza Kazimi; Paul King; Ameya Kolarkar; Elie Korkmaz; Wolfgang Korsch; Serge Kox; Joachim Kuhn; Jeff Lachniet; Lawrence Lee; Jason Lenoble; Eric Liatard; J. Liu; Berenice Loupias; A. Lung; Glen MacLachlan; Dominique Marchand; J.W. Martin; Kenneth McFarlane; Daniella Mckee; Robert McKeown; Fernand Merchez; Hamlet Mkrtchyan; Bryan Moffit; M. Morlet; Itaru Nakagawa; Kazutaka Nakahara; Melissa Nakos; Retief Neveling; Silvia Niccolai; S. Ong; Shelley Page; Vassilios Papavassiliou; Stephen Pate; Sarah Phillips; Mark Pitt; Benard Poelker; Tracy Porcelli; Gilles Quemener; Brian Quinn; William Ramsay; Aamer Rauf; Jean-Sebastien Real; Julie Roche; Philip Roos; Gary Rutledge; Jeffery Secrest; Neven Simicevic; G.R. Smith; Damon Spayde; Samuel Stepanyan; Marcy Stutzman; Vincent Sulkosky; Vardan Tadevosyan; Raphael Tieulent; Jacques Van de Wiele; Willem van Oers; Eric Voutier; William Vulcan; G. Warren; S.P. Wells; Steven Williamson; S.A. Wood; Chen Yan; Junho Yun; Valdis Zeps
2005-06-01
We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < Q{sup 2} < 1.0 GeV{sup 2}. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange quark contributions to the currents of the proton. The measurements were made at JLab using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate non-zero, Q{sup 2} dependent, strange quark contributions and provide new information beyond that obtained in previous experiments.
High Precision Measurement of the Proton Elastic Form Factor Ratio at Low Q^{2}
Zhan, Xiaohui
2010-01-01
Experiment E08-007 measured the proton elastic form factor ratio μ_{p}G_{E}/G_{M} in the range of Q^{2} = 0.3-0.7(GeV/c)^{2} by recoil polarimetry. Data were taken in 2008 at the Thomas Jefferson National Accelerator Facility in Virginia, USA. A 1.2 GeV polarized electron beam was scattered off a cryogenic hydrogen target. The recoil proton was detected in the left HRS in coincidence with the elasticly scattered electrons tagged by the BigBite spectrometer. The proton polarization was measured by the focal plane polarimeter (FPP). In this low Q^{2} region, previous measurement from Jefferson Lab Hall A (LEDEX) along with various fits and calculations indicate substantial deviations of the ratio from unity. For this new measurement, the proposed statistical uncertainty (< 1%) was achieved. These new results are a few percent lower than expected from previous world data and fits, which indicate a smaller G_{Ep} at this region. Beyond the intrinsic interest in nucleon structure, the new results also have implications in determining the proton Zemach radius and the strangeness form factors from parity violation experiments.
Elastic Neutron Scattering at 96 MeV
NASA Astrophysics Data System (ADS)
Hildebrand, A.; Blomgren, J.; Ataç, A.; Bergenwall, B.; Johansson, C.; Klug, J.; Mermod, P.; Nilsson, L.; Pomp, S.; Österlund, M.; Dangtip, s.; Tippawan, U.; Phansuke, P.; Jonsson, O.; Renberg, P.-U.; Prokofiev, A.; Nadel-Turonski, P.; Elmgren, K.; Olsson, N.; Blideanu, V.; Le Brun, C.; Lecolley, J.-F.; Lecolley, F.-R.; Louvel, M.; Marie-Noury, N.; Schweitzer, C.; Eudes, Ph.; Haddad, F.; Lebrun, C.; Koning, A. J.
2005-05-01
A facility for detection of scattered neutrons in the energy interval 50-130 MeV, SCANDAL (SCAttered Nucleon Detection AssembLy), has recently been installed at the 20 - 180-MeV neutron beam line of The Svedberg Laboratory, Uppsala. Elastic neutron scattering from 12C, 16O, 56Fe, 89Y, and 208Pb has been studied at 96 MeV in the 10 - 70° interval. The results from 12C and 208Pb have recently been published,6 while the data from 16O, 56Fe, and 89Y are under analysis. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated normalization uncertainty, 3%, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. The results are compared with modern optical model predictions, based on phenomenology or microscopic theory. Applications for these measurements are nuclear-waste incineration, single-event upsets in electronics, and fast-neutron therapy.
Elastic scattering of slow electrons by n-pentanol alcohol
NASA Astrophysics Data System (ADS)
de Oliveira, Eliane M.; Varella, Márcio T. do N.; Bettega, Márcio H. F.; Lima, Marco A. P.
2014-03-01
We report elastic integral (ICS), differential (DCS) and momentum transfer cross sections (MTCS) for low-energy electron scattering by n-pentanol alcohol in the gas phase. The Schwinger multichannel method implemented with pseudopotentials was employed in the calculations. The DCSs were computed for energies from 1 to 50 eV and the ICS and MTCS from 1 to 100 eV. Due to the significant value of the electric dipole moment, the DCSs are dominated by strong forward scattering. Despite this fact, the DCS around 10 eV displays a behavior related to a f-wave scattering pattern at intermediate angles which may be associated with shape resonances. This result is consistent with the ICS and the MTCS since they show a pronounced peak near this energy. For energies below 1 eV, the MTCS obtained in the static-exchange plus polarization approximation does not increase, as expected for polar molecules, suggesting that a Ramsauer-Townsend minimum could be present. This finding motivated us to revisit the previously studied methanol, ethanol, n-propanol and n-butanol molecules and to perform new calculations for impact energies below 1 eV (not addressed before). With the inclusion of polarization effects, the MTCS for the five alcohols suggest a Ramsauer-Townsend minimum coming from the negative to the positive scattering energies. To the best of our knowledge, there are neither experimental nor calculated cross sections for comparison with the present results.
Low energy elastic electron scattering from CF3Br molecules.
Hargreaves, L R; Brunton, J R; Maddern, T M; Brunger, M J
2015-03-28
CF3Br is a potentially valuable precursor molecule for generating beams of gas phase Br radicals suitable for electron collisions studies. However, the utility of CF3Br for this purpose depends critically on the availability of sound scattering cross sections to allow the contribution of the precursor to be isolated within the total scattering signal. To this end, here we present elastic differential cross section (DCS) measurements for CF3Br at incident energies between 15 and 50 eV. Comparison of these DCSs to those from the only other available experimental study [Sunohara et al., J. Phys. B: At., Mol. Opt. Phys. 36, 1843 (2003)] and a Schwinger multichannel with pseudo potentials (SMCPPs) calculation [Bettega et al., J. Phys. B: At., Mol. Opt. Phys. 36, 1263 (2003)] shows generally a very good accord. Integral elastic and momentum transfer cross sections, derived from our DCSs, are also found to be in quite good agreement with the SMCPP results. PMID:25833582
A covariant multiple scattering series for elastic projectile-target scattering
NASA Technical Reports Server (NTRS)
Gross, Franz; Maung-Maung, Khin
1989-01-01
A covariant formulation of the multiple scattering series for the optical potential is presented. The case of a scalar nucleon interacting with a spin zero isospin zero A-body target through meson exchange, is considered. It is shown that a covariant equation for the projectile-target t-matrix can be obtained which sums the ladder and crossed ladder diagrams efficiently. From this equation, a multiple scattering series for the optical potential is derived, and it is shown that in the impulse approximation, the two-body t-matrix associated with the first order optical potential is the one in which one particle is kept on mass-shell. The meaning of various terms in the multiple scattering series is given. The construction of the first-order optical potential for elastic scattering calculations is described.
Limits on dark matter proton scattering from neutrino telescopes using micrOMEGAs
Bélanger, G.; Silva, J. Da; Perrillat-Bottonet, T.; Pukhov, A.
2015-12-17
Limits on dark matter spin dependent elastic scattering cross section on protons derived from IceCube data are obtained for different dark matter annihilation channels using micrOMEGAs. The uncertainty on the derived limits, estimated by using different neutrino spectra, can reach a factor two. For all dark matter annihilation channels except for quarks, the limits on the spin dependent cross section are more stringent than those obtained in direct detection experiments. The new functions that allow to derive those limits are described.
Determination of the cervical transformation zone using elastic-scattering spectroscopy
Bigio, I.J.; Johnson, T.M.; Mourant, J.R.
1996-04-01
Optical measurements of the cervical transformation zone (sometimes referred to as the transition zone) using elastic-scattering spectroscopy, demonstrate sensitivity to the epithelial cell-type differences.
Evaluation of the forward Compton scattering off protons: Spin-independent amplitude
NASA Astrophysics Data System (ADS)
Gryniuk, Oleksii; Hagelstein, Franziska; Pascalutsa, Vladimir
2015-10-01
We evaluate the forward Compton scattering off the proton, based on Kramers-Kronig kind of relations which express the Compton amplitudes in terms of integrals of total photoabsorption cross sections. We obtain two distinct fits to the world data on the unpolarized total photoabsorption cross section and evaluate the various spin-independent sum rules using these fits. For the sum of proton electric and magnetic dipole polarizabilities governed by the Baldin sum rule, we obtain the following average (between the two fits): αE 1+βM 1=14.0 (2 )×1 0-4 fm3 . An analogous sum rule involving the quadrupole polarizabilities of the proton is evaluated too. The spin-independent forward amplitude of proton Compton scattering is evaluated in a broad energy range. The results are compared with previous evaluations and the only experimental data point for this amplitude (at 2.2 GeV). We remark on sum rules for the elastic component of polarizabilities.
NASA Astrophysics Data System (ADS)
Cao, Xing; Ni, Binbin; Liang, Jun; Xiang, Zheng; Wang, Qi; Shi, Run; Gu, Xudong; Zhou, Chen; Zhao, Zhengyu; Fu, Song; Liu, Jiang
2016-02-01
This is a companion study to Liang et al. (2014) which reported a "reversed" energy-latitude dispersion pattern of ion precipitation in that the lower energy ion precipitation extends to lower latitudes than the higher-energy ion precipitation. Electromagnetic ion cyclotron (EMIC) waves in the central plasma sheet (CPS) have been suggested to account for this reversed-type ion precipitation. To further investigate the association, we perform a comprehensive study of pitch angle diffusion rates induced by EMIC wave and the resultant proton loss timescales at L = 8-12 around the midnight. Comparing the proton scattering rates in the Earth's dipole field and a more realistic quiet time geomagnetic field constructed from the Tsyganenko 2001 (T01) model, we find that use of a realistic, nondipolar magnetic field model not only decreases the minimum resonant energies of CPS protons but also considerably decreases the limit of strong diffusion and changes the proton pitch angle diffusion rates. Adoption of the T01 model increases EMIC wave diffusion rates at > ~ 60° equatorial pitch angles but decreases them at small equatorial pitch angles. Pitch angle scattering coefficients of 1-10 keV protons due to H+ band EMIC waves can exceed the strong diffusion rate for both geomagnetic field models. While He+ and O+ band EMIC waves can only scatter tens of keV protons efficiently to cause a fully filled loss cone at L > 10, in the T01 magnetic field they can also cause efficient scattering of ~ keV protons in the strong diffusion limit at L > 10. The resultant proton loss timescales by EMIC waves with a nominal amplitude of 0.2 nT vary from a few hours to several days, depending on the wave band and L shell. Overall, the results demonstrate that H+ band EMIC waves, once present, can act as a major contributor to the scattering loss of a few keV protons at lower L shells in the CPS, accounting for the reversed energy-latitude dispersion pattern of proton precipitation at low
Elastic scattering of Al25+p to explore the resonance structure in Si26
NASA Astrophysics Data System (ADS)
Jung, H. S.; Lee, C. S.; Kwon, Y. K.; Moon, J. Y.; Lee, J. H.; Yun, C. C.; Kim, M. J.; Hashimoto, T.; Yamaguchi, H.; Kahl, D.; Kubono, S.; Wakabayashi, Y.; Togano, Y.; Choi, Seonho; Kim, Y. H.; Kim, Y. K.; Park, J. S.; Kim, E. J.; Moon, C.-B.; Teranishi, T.; Iwasa, N.; Yamada, T.; Kato, S.; Cherubini, S.; Hayakawa, S.; Rapisarda, G. G.
2014-09-01
Background: The properties of resonances in Si26 are important to better constrain the Al25(p,γ)Si26 reaction rate relevant to the synthesis of galactic Al26gs and energy generation in explosive stellar environment at higher temperature. Purpose: Al25+p elastic scattering was measured to further constrain and investigate disagreements in resonance parameters for the high-lying excited states of Si26 with high statistics and without background contamination within the target. Methods: The experiment was performed by bombarding a thick H2 target with an Al25 radioactive ion beam. The resonances at excitation energies of 6.6-8.3 MeV in the Si26 compound nucleus were studied at the low-energy radioactive-ion beam facility CRIB (Center for Nuclear Study Radioactive Ion Beam separator) at the University of Tokyo. Results: Six resonant states were observed and their resonance parameters were extracted by an R-matrix analysis. Our resonance parameters for two levels are in good agreement with the results of previous studies, while for four others, excitation energy, proton partial width, and spin-parity assignment disagree with the results of recent study via elastic scattering of Al25+p. Conclusion: The parameters of resonant states in Si26 determined in the present work for the Al25(p,γ)Si26 reaction rate are consistent with that of the previous result, solving spin-parity assignment discrepancies between experiments, relevant at higher temperatures.
Proton radiography, nuclear cross sections and multiple Coulomb scattering
Sjue, Sky K.
2015-11-04
The principles behind proton radiography including multiple Coulomb scattering are discussed for a purely imaginary square well nucleus in the eikonal approximation. It is found that a very crude model can reproduce the angular dependence of the cross sections measured at 24 GeV/c. The largest differences are ~3% for the 4.56 mrad data, and ~4% for the 6.68 mrad data. The prospect of understanding how to model deterministically high-energy proton radiography over a very large range of energies is promising, but it should be tested more thoroughly.
Elastic electron-deuteron scattering within a relativistic potential model
Khokhlov, N. A. Vakulyuk, A. A.
2015-01-15
Elastic electron-deuteron scattering was considered in the point form of relativistic quantum mechanics. Observables of this process and the dependence of the deuteron form factors on the 4-momentum transfer Q up to 8 fm{sup −1} were calculated. The nucleon-nucleon potentials used in the calculations included the Nijmegen potentials NijmI and NijmII, the Bonn potential CD-Bonn, and the Moscow potential involving forbidden states. A parametrization of the nucleon form factors that complies with present-day experimental results was used as input data. The results of the calculations that employ all of the above potential types describe experimental data at least up to Q ≈ 5 fm{sup −}1.
Folding model calculations for 6He+12C elastic scattering
NASA Astrophysics Data System (ADS)
Awad, A. Ibraheem
2016-03-01
In the framework of the double folding model, we used the α+2n and di-triton configurations for the nuclear matter density of the 6He nucleus to generate the real part of the optical potential for the system 6He+12C. As an alternative, we also use the high energy approximation to generate the optical potential for the same system. The derived potentials are employed to analyze the elastic scattering differential cross section at energies of 38.3, 41.6 and 82.3 MeV/u. For the imaginary part of the potential we adopt the squared Woods-Saxon form. The obtained results are compared with the corresponding measured data as well as with available results in the literature. The calculated total reaction cross sections are investigated and compared with the optical limit Glauber model description.
Proton Magnetic Form Factor from Existing Elastic e-p Cross Section Data
NASA Astrophysics Data System (ADS)
Ou, Longwu; Christy, Eric; Gilad, Shalev; Keppel, Cynthia; Schmookler, Barak; Wojtsekhowski, Bogdan
2015-04-01
The proton magnetic form factor GMp, in addition to being an important benchmark for all cross section measurements in hadron physics, provides critical information on proton structure. Extraction of GMp from e-p cross section data is complicated by two-photon exchange (TPE) effects, where available calculations still have large theoretical uncertainties. Studies of TPE contributions to e-p scattering have observed no nonlinear effects in Rosenbluth separations. Recent theoretical investigations show that the TPE correction goes to 0 when ɛ approaches 1, where ɛ is the virtual photon polarization parameter. In this talk, existing e-p elastic cross section data are reanalyzed by extrapolating the reduced cross section for ɛ approaching 1. Existing polarization transfer data, which is supposed to be relatively immune to TPE effects, are used to produce a ratio of electric and magnetic form factors. The extrapolated reduced cross section and polarization transfer ratio are then used to calculate GEp and GMp at different Q2 values.
Park, Yang-Kyun; Sharp, Gregory C.; Phillips, Justin; Winey, Brian A.
2015-01-01
Purpose: To demonstrate the feasibility of proton dose calculation on scatter-corrected cone-beam computed tomographic (CBCT) images for the purpose of adaptive proton therapy. Methods: CBCT projection images were acquired from anthropomorphic phantoms and a prostate patient using an on-board imaging system of an Elekta infinity linear accelerator. Two previously introduced techniques were used to correct the scattered x-rays in the raw projection images: uniform scatter correction (CBCTus) and a priori CT-based scatter correction (CBCTap). CBCT images were reconstructed using a standard FDK algorithm and GPU-based reconstruction toolkit. Soft tissue ROI-based HU shifting was used to improve HU accuracy of the uncorrected CBCT images and CBCTus, while no HU change was applied to the CBCTap. The degree of equivalence of the corrected CBCT images with respect to the reference CT image (CTref) was evaluated by using angular profiles of water equivalent path length (WEPL) and passively scattered proton treatment plans. The CBCTap was further evaluated in more realistic scenarios such as rectal filling and weight loss to assess the effect of mismatched prior information on the corrected images. Results: The uncorrected CBCT and CBCTus images demonstrated substantial WEPL discrepancies (7.3 ± 5.3 mm and 11.1 ± 6.6 mm, respectively) with respect to the CTref, while the CBCTap images showed substantially reduced WEPL errors (2.4 ± 2.0 mm). Similarly, the CBCTap-based treatment plans demonstrated a high pass rate (96.0% ± 2.5% in 2 mm/2% criteria) in a 3D gamma analysis. Conclusions: A priori CT-based scatter correction technique was shown to be promising for adaptive proton therapy, as it achieved equivalent proton dose distributions and water equivalent path lengths compared to those of a reference CT in a selection of anthropomorphic phantoms. PMID:26233175
Polarized lepton-nucleon elastic scattering and a search for a light scalar boson
NASA Astrophysics Data System (ADS)
Liu, Yu-Sheng; Miller, Gerald A.
2015-09-01
Lepton-nucleon elastic scattering, using the one-photon and one-scalar-boson exchange mechanisms considering all possible polarizations, is used to study searches for a new scalar boson and suggest new measurements of the nucleon form factors. A new light scalar boson, which feebly couples to leptons and nucleons, may account for the proton radius and muon g -2 puzzles. We show that the scalar boson produces relatively large effects in a certain kinematic region when using sufficient control of lepton and nucleon spin polarization. We generalize current techniques to measure the ratio GE:GM and present a new method to separately measure GM2 and GE2 using polarized incoming and outgoing muons.
NASA Technical Reports Server (NTRS)
Berger, Pascal; Sayir, Ali; Berger, Marie-Helene
2004-01-01
The interaction between hydrogen and various high temperature protonic conductors (HTPC) has not been clearly understood due to poor densification and unreacted secondary phases. the melt-processing technique is used in producing fully dense simple SrCe(0.9)Y (0.10) O(3-delta) and complex Sr3Ca(1+x)Nb(2+x)O(9-delta) perovskites that can not be achieved by solid-state sintering. the possibilities of ion beam analysis have been investigated to quantify hydrogen distribution in HTPC perovskites subjected to water heat treatment. Nuclear microprobe technique is based on the interactions of a focused ion beam of MeV light ions (H-1, H-2, He-3, He-4,.) with the sample to be analyzed to determine local elemental concentrations at the cubic micrometer scale, the elastic recoil detection analysis technique (ERDA) has been carried out using He-4(+) microbeams and detecting the resulting recoil protons. Mappings of longitudinal sections of water treated SrCeO3 and Sr(Ca(1/3)Nb(2/3))O3 perovskites have been achieved, the water treatment strongly alters the surface of simple SrCe(0.9)Y(0.10)O(3-delta) perovskite. From Rutherford Back Scattering measurements (RBS), both Ce depletion and surface re-deposition is evidenced. the ERDA investigations on water treated Sr3Ca(1+x)Nb(2+x)O(9-delta) perovskite did not exhibit any spatial difference for the hydrogen incorporation from the surface to the centre. the amount of hydrogen incorporation for Sr3Ca(1+x)Nb(2+x)O(9-delta) was low and required further development of two less conventional techniques, ERDA in forward geometry and forward elastic diffusion H-1(p,p) H-1 with coincidence detection.
Proton scattering by a hydrogen atom in an effectively two-body model
Pupyshev, V. V.
2013-02-15
It is assumed that the total potential of proton interaction with a hydrogen atom is the sum of the short-range nuclear soft-core Reid potential and the long-range Thomas-Fermi potential. A quantum mechanical analysis of low-energy features of the phase shift and cross section for elastic proton scattering on a hydrogen atom is given for the case of zero total angular momentum. The calculations performed in the present study within a nonlinear version of the variable-phase approach ultimately revealed that, because of a long-range character of the asymptotic behavior of the Thomas-Fermi potential, the respective cross section at low energies oscillates but has a finite number of zeros.
Determination of the Proton's Weak Charge via Parity Violating Electron Scattering
Hoskins, Joshua Russell
2015-08-01
The Qweak experiment, which completed running in May of 2012 at Jefferson Laboratory, has measured the parity-violating asymmetry in elastic electron-proton scattering at four-momentum transfer Q^{2}=0.025 (GeV/c)^{2} in order to provide the first direct measurement of the proton's weak charge, Qpw. The Standard Model makes firm predictions for the weak charge; deviations from the predicted value would provide strong evidence of new physics beyond the Standard Model. Using an 89% polarized electron beam at 145 microA scattering from a 34.4 cm long liquid hydrogen target, scattered electrons were detected using an array of eight fused-silica detectors placed symmetric about the beam axis. The parity-violating asymmetry was then measured by reversing the helicity of the incoming electrons and measuring the normalized difference in rate seen in the detectors. The low Q^{2} enables a theoretically clean measurement; the higher order hadronic corrections are constrained using previous parity-violating electron scattering world data. The experimental method will be discussed, with recent results constituting 4% of our total data and projections of our proposed uncertainties on the full data set.
Elastic and inelastic scattering of neutrons from 56Fe
NASA Astrophysics Data System (ADS)
Ramirez, Anthony Paul; McEllistrem, M. T.; Liu, S. H.; Mukhopadhyay, S.; Peters, E. E.; Yates, S. W.; Vanhoy, J. R.; Harrison, T. D.; Rice, B. G.; Thompson, B. K.; Hicks, S. F.; Howard, T. J.; Jackson, D. T.; Lenzen, P. D.; Nguyen, T. D.; Pecha, R. L.
2015-10-01
The differential cross sections for elastic and inelastic scattered neutrons from 56Fe have been measured at the University of Kentucky Accelerator Laboratory (www.pa.uky.edu/accelerator) for incident neutron energies between 2.0 and 8.0 MeV and for the angular range 30° to 150°. Time-of-flight techniques and pulse-shape discrimination were employed for enhancing the neutron energy spectra and for reducing background. An overview of the experimental procedures and data analysis for the conversion of neutron yields to differential cross sections will be presented. These include the determination of the energy-dependent detection efficiencies, the normalization of the measured differential cross sections, and the attenuation and multiple scattering corrections. Our results will also be compared to evaluated cross section databases and reaction model calculations using the TALYS code. This work is supported by grants from the U.S. Department of Energy-Nuclear Energy Universities Program: NU-12-KY-UK-0201-05, and the Donald A. Cowan Physics Institute at the University of Dallas.
Quasi-elastic electron scattering in uranium-238
Blatchley, C.C.
1984-01-01
Electron scattering data from the MIT-Bates linear accelerator were used to derive longitudinal and transverse response functions (S/sub L/, S/sub T/) for the quasi-elastic (QE) kinematic region from uranium targets. Incident energies ranged from 100 to 690 MeV at five laboratory scattering angles: 60, 90, 134.5, 140, and 160C. The Rosenbluth separations using all five angles were obtained at three momentum transfers (q) from 250 to 500 MeV/c. Both response functions compared well to relativistic Fermi Gas Model (FGM) predictions at higher values of q, but the S/sub L/ peak was progressively lower and broader than the FGM at lower q. This difference in response was reflected in the longitudinal sum rule and in the evaluation of y-scaling. The S/sub L/ integrated strength was generally about 30% larger than the transverse FGM strength throughout. The S/sub L/ sum, however, was reduced to about 60% of the model prediction at lower values of q and increased to almost 100% as q increased to 500 MeV/c. No significant quenching in S/sub L/ was observed at the larger values of q.
Ma, Guo -Liang; Bzdak, Adam
2014-11-04
In this study, we show that the incoherent elastic scattering of partons, as present in a multi-phase transport model (AMPT), with a modest parton–parton cross-section of σ = 1.5 – 3 mb, naturally explains the long-range two-particle azimuthal correlation as observed in proton–proton and proton–nucleus collisions at the Large Hadron Collider.
Effect of strangeness for neutrino (antineutrino) scattering in the quasi-elastic region
Kim, K. S.; Yu, Byung Geel; Cheoun, Myung-Ki
2008-05-15
We present the neutral- and charged-current reactions by incident neutrino (antineutrino) scattering on the nucleon and on the {sup 12}C target in the quasi-elastic region within the framework of a relativistic single-particle model. The incident energies at 500 MeV and 1 GeV are used for the scattering. Effects of strangeness are studied thoroughly on the cross sections, the ratios between the neutral- and charged-current reactions, and the asymmetries by incident neutrino and antineutrino. We find that there exists some cancellation of the strange quark contributions between the knocked-out protons and neutrons in the neutrino (antineutrino)-nucleus scattering. The effect of strangeness is exhibited more strongly on the asymmetry than on the ratio or cross section. On a difference of the asymmetry, the effect of strangeness appears strongly, but on a summation of the asymmetry, the effect almost disappears in the low and middle kinetic energies of the knocked-out nucleon.
Signature for g bosons from medium energy proton scattering experiments
Kuyucak, S.
1993-10-01
We apply the recently developed algebraic (1/N expansion) scattering formalism to medium energy proton scattering from {sup 154}Sm and {sup 176}Yb. The nuclear structure effects in this formalism are described by the interacting boson model generalized to arbitrary interactions and types of bosons i.e. s,d,g, etc. We find that, in the sd boson model, a consistent description of cross sections is possible only for the 0{sup +} and 2{sup +} states. The failure of the model with regard to the 4{sup +} states indicates that the effective hexadecapole operator used in the sd model is inadequate. In contrast, the data for scattering to the 0{sup +}, 2{sup +} and 4{sup +} states could be consistently described in the sdg boson model. The spectroscopic data for the low-lying levels usually can not distinguish between the sd and sdg models due to renormalization of parameters, and one has to look at high spin or energy data for evidence of g bosons. The inelastic proton scattering experiments, on the other hand, directly probe the wave functions, and hence could provide a signature for g bosons even in the ground band states.
Rhodopsin photoactivation dynamics revealed by quasi-elastic neutron scattering
Bhowmik, Debsindhu; Shrestha, Utsab; Perera, Suchithranga M.d.c.; Chawla, Udeep; Mamontov, Eugene; Brown, Michael F.; Chu, Xiang -Qiang
2015-01-27
Rhodopsin is a G-protein-coupled receptor (GPCR) responsible for vision under dim light conditions. During rhodopsin photoactivation, the chromophore retinal undergoes cis-trans isomerization, and subsequently dissociates from the protein yielding the opsin apoprotein [1]. What are the changes in protein dynamics that occur during the rhodopsin photoactivation process? Here, we studied the microscopic dynamics of the dark-state rhodopsin and the ligand-free opsin using quasi-elastic neutron scattering (QENS). The QENS technique tracks the individual hydrogen atom motions in the protein molecules, because the neutron scattering cross-section of hydrogen is much higher than other atoms [2-4]. We used protein (rhodopsin/opsin) samples with CHAPSmore » detergent hydrated with heavy water. The solvent signal is suppressed due to the heavy water, so that only the signals from proteins and detergents are detected. The activation of proteins is confirmed at low temperatures up to 300 K by the mean-square displacement (MSD) analysis. Our QENS experiments conducted at temperatures ranging from 220 K to 300 K clearly indicate that the protein dynamic behavior increases with temperature. The relaxation time for the ligand-bound protein rhodopsin was longer compared to opsin, which can be correlated with the photoactivation. Moreover, the protein dynamics are orders of magnitude slower than the accompanying CHAPS detergent, which forms a band around the protein molecule in the micelle. Unlike the protein, the CHAPS detergent manifests localized motions that are the same as in the bulk empty micelles. Furthermore QENS provides unique understanding of the key dynamics involved in the activation of the GPCR involved in the visual process.« less
Rhodopsin photoactivation dynamics revealed by quasi-elastic neutron scattering
Bhowmik, Debsindhu; Shrestha, Utsab; Perera, Suchithranga M.d.c.; Chawla, Udeep; Mamontov, Eugene; Brown, Michael F.; Chu, Xiang -Qiang
2015-01-27
Rhodopsin is a G-protein-coupled receptor (GPCR) responsible for vision under dim light conditions. During rhodopsin photoactivation, the chromophore retinal undergoes cis-trans isomerization, and subsequently dissociates from the protein yielding the opsin apoprotein [1]. What are the changes in protein dynamics that occur during the rhodopsin photoactivation process? Here, we studied the microscopic dynamics of the dark-state rhodopsin and the ligand-free opsin using quasi-elastic neutron scattering (QENS). The QENS technique tracks the individual hydrogen atom motions in the protein molecules, because the neutron scattering cross-section of hydrogen is much higher than other atoms [2-4]. We used protein (rhodopsin/opsin) samples with CHAPS detergent hydrated with heavy water. The solvent signal is suppressed due to the heavy water, so that only the signals from proteins and detergents are detected. The activation of proteins is confirmed at low temperatures up to 300 K by the mean-square displacement (MSD) analysis. Our QENS experiments conducted at temperatures ranging from 220 K to 300 K clearly indicate that the protein dynamic behavior increases with temperature. The relaxation time for the ligand-bound protein rhodopsin was longer compared to opsin, which can be correlated with the photoactivation. Moreover, the protein dynamics are orders of magnitude slower than the accompanying CHAPS detergent, which forms a band around the protein molecule in the micelle. Unlike the protein, the CHAPS detergent manifests localized motions that are the same as in the bulk empty micelles. Furthermore QENS provides unique understanding of the key dynamics involved in the activation of the GPCR involved in the visual process.
Universal quantification of elastic scattering effects in AES and XPS
NASA Astrophysics Data System (ADS)
Jablonski, Aleksander
1996-09-01
Elastic scattering of photoelectrons in a solid can be accounted for in the common formalism of XPS by introducing two correction factors, βeff and Qx. In the case of AES, only one correction factor, QA, is required. As recently shown, relatively simple analytical expressions for the correction factors can be derived from the kinetic Boltzmann equation within the so-called "transport approximation". The corrections are expressed here in terms of the ratio of the transport mean free path (TRMFP) to the inelastic mean free path (IMFP). Since the available data for the TRMFP are rather limited, it was decided to complete an extensive database of these values. They were calculated in the present work for the same elements and energies as in the IMFP tabulation published by Tanuma et al. An attempt has been made to derive a predictive formula providing the ratios of the TRMFP to the IMFP. Consequently, a very simple and accurate algorithm for calculating the correction factors βeff, Qx and QA has been developed. This algorithm can easily be generalized to multicomponent solids. The resulting values of the correction factors were found to compare very well with published values resulting from Monte Carlo calculations.
Quantum diffraction grating: A possible new description of nuclear elastic scattering
NASA Astrophysics Data System (ADS)
Wojciechowski, H.
2016-02-01
The problem of discontinuous functions and their representations in the form of Legendre polynomial series in quantum nuclear scattering theory is presented briefly. The problem is quite old yet not adequately explained in numerous Quantum Theory textbooks and sometimes not correctly understood by physicists. Introduction of the generalized functions into the quantum scattering theory clarifies the problem and allows to propose new interpretations of nuclear elastic scattering phenomenon. The derived new forms of the full elastic scattering amplitudes and possibility of splitting them suggest existence of dynamical quantum diffraction grating around the nuclei. Particularly important fact is that this grating existing in the space around the nucleus makes considerable contribution to the experimental elastic differential cross-section. All these might be quite important in analyses of nuclear elastic scattering data and so require to be stated in a more detailed and clear way.
NASA Astrophysics Data System (ADS)
Kimstrand, Peter; Traneus, Erik; Ahnesjö, Anders; Tilly, Nina
2008-07-01
Collimators are routinely used in proton radiotherapy to laterally confine the field and improve the penumbra. Collimator scatter contributes up to 15% of the local dose and is therefore important to include in treatment planning dose calculation. We present a method for reconstruction of the collimator scatter phase space based on the parametrization of pre-calculated scatter kernels. Collimator scatter distributions, generated by the Monte Carlo (MC) package GEANT4.8.2, were scored differential in direction and energy. The distributions were then parametrized so as to enable a fast reconstruction by sampling. MC calculated dose distributions in water based on the parametrized phase space were compared to full MC simulations that included the collimator in the simulation geometry, as well as to experimental data. The experiments were performed at the scanned proton beam line at the The Svedberg Laboratory (TSL) in Uppsala, Sweden. Dose calculations using the parametrization of this work and the full MC for isolated typical cases of collimator scatter were compared by means of the gamma index. The result showed that in total 96.7% (99.3%) of the voxels fulfilled the gamma 2.0%/2.0 mm (3.0%/3.0 mm) criterion. The dose distribution for a collimated field was calculated based on the phase space created by the collimator scatter model incorporated into the generation of the phase space of a scanned proton beam. Comparing these dose distributions to full MC simulations, including particle transport in the MLC, yielded that in total for 18 different collimated fields, 99.1% of the voxels satisfied the gamma 1.0%/1.0 mm criterion and no voxel exceeded the gamma 2.6%/2.6 mm criterion. The dose contribution of collimator scatter along the central axis as predicted by the model showed good agreement with experimental data.
NASA Astrophysics Data System (ADS)
Sekiguchi, K.; Wada, Y.; Miyazaki, J.; Taguchi, T.; Gebauer, U.; Dozono, M.; Kawase, S.; Kubota, Y.; Lee, C. S.; Maeda, Y.; Mashiko, T.; Miki, K.; Okamura, H.; Sakaguchi, S.; Sakai, H.; Sakamoto, N.; Sasano, M.; Shimizu, Y.; Takahashi, K.; Tang, T. L.; Uesaka, T.; Wakasa, T.; Yako, K.
With the aim of clarifying roles of the 3NFs in nuclei experimental programs with polarized deuterons beams at intermediate energies are in progress at RIKEN RI Beam Factory. As the first step, we have measured a complete set of deuteron analyzing powers in deuteron-proton elastic scattering at 250 and 294 MeV/nucleon. The obtained data are compared with the Faddeev calculations based on the modern nucleon-nucleon forces together with the Tucson-Melbourne'99, and UrbanaIX three nucleon forces.
NASA Astrophysics Data System (ADS)
Sekiguchi, K.; Okamura, H.; Wada, Y.; Miyazaki, J.; Taguchi, T.; Gebauer, U.; Dozono, M.; Kawase, S.; Kubota, Y.; Lee, C. S.; Maeda, Y.; Mashiko, T.; Miki, K.; Sakaguchi, S.; Sakai, H.; Sakamoto, N.; Sasano, M.; Shimizu, Y.; Takahashi, K.; Tang, R.; Uesaka, T.; Wakasa, T.; Yako, K.
2014-08-01
With the aim of clarifying roles of the 3NFs in nuclei experimental programs with the polarized deuteron beam at intermediate energies are in progress at RIKEN RI Beam Factory. As the first step, we have measured a complete set of deuteron analyzing powers in deuteron-proton elastic scattering at 250 and 294 MeV/nucleon. The obtained data are compared with the Faddeev calculations based on the modern nucleon-nucleon forces together with the Tucson-Melbourne'99, and UrbanaIX three nucleon forces.
Liu, Fengming; Liu, Zhengyou
2015-10-23
We theoretically investigate elastic waves propagating in metamaterials with simultaneous zero indices for both the longitudinal and transverse waves. With scattering objects (here cylinders) present in the metamaterial slabs, while the elastic waves can mostly transmit through the metamaterial slabs perfectly, exhibiting the well-known cloaking effect of zero-index metamaterials, they nevertheless become totally blocked at resonances, indicating strong elastic wave scattering by the objects in the cases. However, despite the occurrence of the elastic wave scattering, there is, counterintuitively, no mode conversion between the longitudinal and transverse waves in the process, completely in contrast to that in conventional elastic media. A design of a two-dimensional phononic crystal with these peculiar properties is presented. PMID:26551124
Liu, Fengming; Liu, Zhengyou
2015-10-23
We theoretically investigate elastic waves propagating in metamaterials with simultaneous zero indices for both the longitudinal and transverse waves. With scattering objects (here cylinders) present in the metamaterial slabs, while the elastic waves can mostly transmit through the metamaterial slabs perfectly, exhibiting the well-known cloaking effect of zero-index metamaterials, they nevertheless become totally blocked at resonances, indicating strong elastic wave scattering by the objects in the cases. However, despite the occurrence of the elastic wave scattering, there is, counterintuitively, no mode conversion between the longitudinal and transverse waves in the process, completely in contrast to that in conventional elastic media. A design of a two-dimensional phononic crystal with these peculiar properties is presented.
Alignment creaction by elastic electron scattering by ions in a plasma
Csanak, G. Y.; Kilcrease, D. P.; Bray, I; Fursa, D. V.
2004-01-01
Alignment creation by elastic hcavy particle scattering has been studied for many years by Oniont, by Dyakonov and Perel, and by Petrashen, Rebane, and Rebane. The technique has been adapted for arbitrary perturbers (including electrons) by Fujimoto et al. and by Fujimoto and Kazantsev. In the case of heavy particle perturbers (e.g. ions) there was an argument by Petrashen, Rebane, and Rebane that under certain conditions (namely only elastic scattering is possible and the semi-classical straight-line trajectory assumption holds) in the case of an isolated level, alignment can not be created by elastic scattering. This contention has been questioned by Dashevskaya and Nikitin who argued that the above conclusion of Petrashen et al. is due to an extra symmetry introduced into the problem by the straight-line trajectory approximation (which introduces detailed balance for magnetic sublevel to magnetic sublevel transitions) and if a more accurate approximation is made alignment creation can be obtained by elastic scattering. See the discussion in Fujimoto et al. In the case of inelastic scattering Kazantsev et al. gave a quantum-mechanical definition of the alignment creation cross section. In carlier works, Trdjrnaf et al. and Csanak et al. adopted the inelastic alignment creation cross section definition of Kazantsev et al. for elastic electron scattering and reported results for Ba and O V ions based on that formula. (Apparently Dashevskaya and Nikitin used the same formula.) However, a closer inspection of the semi-classical formula of Fujimoto et al. and Fujimoto and Kazantsev 1141 as well as the quantum-mechanical rate equations of Ben-Reuven and Nienhuis and Bommier and Sahal-Brechot also indicated that the inelastic scattering fomiula might not hold for elastic scattering. The present work reinvestigates this problem, and shows that indeed the alignment creation cross section formula is different for elastic scattering, as compared to the inelastic Scattering
Elastic light scattering by the atoms of a Bose gas confined in a parabolic trap
Alekseev, V. A.
2008-09-15
It is shown that the emergence of a condensate fraction in a gas confined in a trap leads to a sharp increase in the intensity of elastic scattering (scattering not accompanied by a change in the quantum numbers describing the motion of gas atoms in the trap) of light. Under typical experimental conditions, this intensity may be thousands of times greater than the intensity of inelastic scattering, which is hardly affected by the condensate. The angular distribution of elastic scattering of light allows one to determine the size of the condensate, and its intensity makes it possible to determine the number of particles trapped in the condensate.
Parton-parton elastic scattering and rapidity gaps at SSC and LHC energies
Duca, V.D.
1993-08-01
The theory of the perturbative pomeron, due to Lipatov and collaborators, is used to compute the probability of observing parton-parton elastic scattering and rapidity gaps between jets in hadron collisions at SSC and LHC energies.
Cancer detection using NIR elastic light scattering and tissue fluorescence imaging
Demos, S G; Staggs, M; Radousky, H B; Gandour-Edwards, R; deVere White, R
2000-12-04
Near infrared imaging using elastic light scattering and tissue fluorescence under long-wavelength laser excitation are explored for cancer detection. Various types of normal and malignant human tissue samples were utilized in this investigation.
Inelastic proton scattering of Sn isotopes studied with GRETINA
NASA Astrophysics Data System (ADS)
Campbell, Christopher
2014-03-01
The chain of semi-magic Sn nuclei, with many stable isotopes, has been a fertile ground for experimental and theoretical studies. Encompassing a major neutron shell from N = 50 to 82, the properties and structure of these nuclei provided important data for the development of the pairing-plus-quadrupole model. Recent experimental information on B(E2) for 106,108,110,112Sn came as a surprise as it indicated a larger collectivity than the predicted parabolic trend of quadrupole collectivity. These data, instead, show an unexpectedly flat trend even as the number of valence particles is reduced from 12 to 6. To fully understand how collectivity is evolving in these isotopes, 108,110,112Sn have been studied using thick-target, inelastic proton scattering with GRETINA tagging inelastic scattering events by detecting gamma-rays from the prompt decay of states excited in the reaction. We will present the trend of 2 + excitation cross-sections, the deduced quadrupole deformation parameters, and observations of other low-lying collective states. Comparison of these (p,p') quadrupole deformation parameters with B(E2) data will provide new insights into the relative importance of proton and neutron contributions to collectivity in these nuclei. GRETINA was funded by the US DOE - Office of Science. Operation of the array at NSCL is supported by NSF under Cooperative Agreement PHY-1102511(NSCL) and DOE under grant DE-AC02-05CH11231(LBNL).
Measurements of electron-proton elastic cross sections for 0.4 < Q{sup 2} < 5.5 (GeV/c){sup 2}
M.E. Christy; Abdellah Ahmidouch; Christopher Armstrong; John Arrington; Razmik Asaturyan; Steven Avery; O. Baker; Douglas Beck; Henk Blok; C.W.Bochna; Werner Boeglin; Peter Bosted; Maurice Bouwhuis; Herbert Breuer; D.S.Brown; Antje Bruell; Roger Carlini; Nicholas Chant; Anthony Cochran; Leon Cole; Samuel Danagoulian; Donal Day; James Dunne; Dipangkar Dutta; Rolf Ent; Howard Fenker; B.Fox; Liping Gan; Haiyan Gao; Kenneth Garrow; David Gaskell; Ashot Gasparian; Don Geesaman; Paul Gueye; Mark Harvey; Roy Holt; Xiaodong Jiang; Cynthia Keppel; Edward Kinney; Yongguang Liang; Wolfgang Lorenzon; Allison Lung; Pete Markowitz; J.W.Martin; Kevin McIlhany; Daniella Mckee; David Meekins; M.A.Miller; Richard Milner; Joseph Mitchell; Hamlet Mkrtchyan; Robert Mueller; Alan Nathan; Gabriel Niculescu; Maria-Ioana Niculescu; Thomas O'neill; Vassilios Papavassiliou; Stephen Pate; Buz Piercey; David Potterveld; Ronald Ransome; Joerg Reinhold; E.Rollinde; Philip Roos; Adam Sarty; Reyad Sawafta; Elaine Schulte; Edwin Segbefia; C.Smith; Stepan Stepanyan; Steffen Strauch; Vardan Tadevosyan; Liguang Tang; Raphael Tieulent; Alicia Uzzle; William Vulcan; Stephen Wood; Feng Xiong; Lulin Yuan; Markus Zeier; Benedikt Zihlmann; Vitaliy Ziskin
2004-01-01
We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The measurements were made at 28 unique kinematic settings covering a range in momentum transfer of 0.4 < Q{sup 2} < 5.5 (/rm GeV/c){sup 2}. These measurements represent a significant contribution to the world's cross section data set in the Q{sup 2} range where a large discrepancy currently exists between the ratio of electric to magnetic proton form factors extracted from previous cross section measurements and that recently measured via polarization transfer in Hall A at Jefferson Lab.
P(P bar)P elastic scattering and cosmic ray data
NASA Technical Reports Server (NTRS)
FAZAL-E-ALEEM; Saleem, M.
1985-01-01
It is shown that the total cross section for pp elastic scattering at cosmic ray energies, as well as the total cross section, the slope parameter b(s,t) and the differential cross section for small momentum transfer at ISR and collider energies for p(p)p elastic scattering can be simultaneously fitted by using a simple Regge pole model. The results of this theory is discussed in detail.
Elastic properties of a polyimide film determined by Brillouin scattering and mechanical techniques
Kumar, R.S.; Schuller, I.K.; Kumar, S.S.; Fartash, A.; Grimsditch, M.
1993-06-01
We discuss here the complete determination of the elastic properties of a polyimide film using two experimental techniques. One technique employs the polymer film as a vibrating membrane and allows a direct determination of the ``macroscopic`` biaxial modulus. Brillouin scattering, which measures the elastic properties on a {approximately} 100{mu} scale, allows for a complete characterization of the elastic behavior. Results obtained by the two techniques are in agreement within reported error bars.
Elastic and inelastic light scattering of colloidal particles
NASA Astrophysics Data System (ADS)
Kerker, M.
1985-06-01
The project has been primarily concerned with both theoretical and experimental aspects of surface enhanced scattering. The theory has been extended to include concentric spherical particles, the effect of surface coverage, enhancement of coherent anti-Stokes Raman scattering and the effect of dielectric cavities. The experimental work included SERS (Surface Enhanced Raman Scattering) from citrate on silver hydrosols, surface enhanced resonance Raman scattering (SERRS) for dabsylaspartate on silver hydrosols, silver organosols and roughened silver electrodes, the effect of aggregates on SERS. In addition there have been ancillary studies dealing with absorption and luminescence by dye coated silver particles, analysis of biological cells by flow fluorimetry, and electromagnetic scattering by magnetic particles.
Nuclear and partonic dynamics in high energy elastic nucleus-nucleus scattering
NASA Astrophysics Data System (ADS)
Małecki, Andrzej
1991-10-01
A hybrid description of diffraction which combines a geometrical modeling of multiple scattering with many-channel effects resulting from intrinsic dynamics on the nuclear and subnuclear level is presented. The application to 4-4He elastic scattering is satisfactory. Our analysis suggests that, at large momentum transfers, the parton constituents of nucleons immersed in nuclei are deconfined.
Nuclear and partonic dynamics in high energy elastic nucleus-nucleus scattering
Malecki, A. )
1991-10-01
A hybrid description of diffraction which combines a geometrical modeling of multiple scattering with many-channel effects resulting from intrinsic dynamics on the nuclear and subnuclear level is presented. The application to {sup 4}He-{sup 4}He elastic scattering is satisfactory. Our analysis suggests that, at large momentum transfers, the parton constituents of nucleons immersed in nuclei are deconfined.
Parity Nonconservation in Proton-Proton and Proton-Water Scattering at 1.5 GeV/c
DOE R&D Accomplishments Database
Mischke, R. E.; Bowman, J. D.; Carlini, R.; MacArthur, D.; Nagle, D. E.; Frauenfelder, H.; Harper, R. W.; Yuan, V.; McDonald, A. B.; Talaga, R. L.
1984-07-01
Experiments searching for parity nonconservation in the scattering of 1.5 GeV/c (800 MeV) polarized protons from an unpolarized water target and a liquid hydrogen target are described. The intensity of the incident proton beam was measured upstream and downstream of the target by a pair of ionization detectors. The beam helicity was reversed at a 30-Hz rate. Auxiliary detectors monitored beam properties that could give rise to false effects. The result for the longitudinal asymmetry from the water is A{sub L} = (1.7 +- 3.3 +- 1.4) x 10{sup -7}, where the first error is statistical and the second is an estimate of systematic effects. The hydrogen data yield a preliminary result of A{sub L} = (1.0 +- 1.6) x 10{sup -7}. The systematic errors for p-p are expected to be < 1 x 10{sup -7}.
Measurements of Compton Scattering on the Proton at 2 - 6 GeV
Danagoulian, Areg
2006-01-01
Similar to elastic electron scattering, Compton Scattering on the proton at high momentum transfers(and high p⊥) can be an effective method to study its short-distance structure. An experiment has been carried out to measure the cross sections for Real Compton Scattering (RCS) on the proton for 2.3-5.7 GeV electron beam energies and a wide distribution of large scattering angles. The 25 kinematic settings sampled a domain of s = 5-11(GeV/c)^{2},-t = -7(GeV/c)^{2} and -u = 0.5-6.5(GeV/c)^{2}. In addition, a measurement of longitudinal and transverse polarization transfer asymmetries was made at a 3.48 GeV beam energy and a scattering angle of θ_{cm }= 120°. These measurements were performed to test the existing theoretical mechanisms for this process as well as to determine RCS form factors. At the heart of the scientific motivation is the desire to understand the manner in which a nucleon interacts with external excitations at the above listed energies, by comparing and contrasting the two existing models – Leading Twist Mechanism and Soft Overlap “Handbag” Mechanism – and identify the dominant mechanism. Furthermore, the Handbag Mechanism allows one to calculate reaction observables in the framework of Generalized Parton Distributions (GPD), which have the function of bridging the wide gap between the exclusive(form factors) and inclusive(parton distribution functions) description of the proton. The experiment was conducted in Hall A of Thomas Jefferson National Accelerator Facility(Jefferson Lab). It used a polarized and unpolarized electron beam, a 6% copper radiator with the thickness of 6.1% radiation lengths (to produce a bremsstrahlung photon beam), the Hall A liquid hydrogen target, a high resolution spectrometer with a focal plane polarimeter, and a photon hodoscope calorimeter. Results of the differential cross sections are presented, and discussed in the general context of the scientific motivation.
Dirac Calculations for Proton Inelastic Scattering at Intermediate Energies
NASA Astrophysics Data System (ADS)
El-Nohy, N. A.; El-Hammamy, M. N.; Aly, N. E.; Abdel-Moneim, A. M.; Hamza, A. F.
2016-09-01
Relativistic proton inelastic scattering from different targets (16O, 24Mg, 28Si, 40Ca, 54Fe, 58Ni, 90Zr, 154Sm, 176Yb, and 208Pb) at intermediate energies is analyzed in the framework of phenomenological optical potentials based on the Dirac formalism. Parameters of the Dirac phenomenological potential with Woods Saxon (WS) shape are obtained. The first order vibrational collective model with one phonon is used to calculate the transition optical potentials to the first low-lying excited state (2+) of the investigated target nuclei. Also, the variation of deformation length (δ) with energy and mass number is studied. It is noticed that the deformation length increases slightly with energy at intermediate range.
Fagundes, D. A.; Menon, M. J.; Silva, P. V.
2013-03-25
We show that the proton-proton elastic differential cross section data at dip position and beyond can be quite well described by a parametrization based on the Tsallis distribution, with only five free fit parameters. Extrapolation of the results obtained at 7 TeV to large momentum transfer, suggests that hadrons may not behave as a black-disk at the asymptotic energy region.
Multiple-scattering model for inclusive proton production in heavy ion collisions
NASA Technical Reports Server (NTRS)
Cucinotta, Francis A.
1994-01-01
A formalism is developed for evaluating the momentum distribution for proton production in nuclear abrasion during heavy ion collisions using the Glauber multiple-scattering series. Several models for the one-body density matrix of nuclei are considered for performing numerical calculations. Calculations for the momentum distribution of protons in abrasion are compared with experimental data for inclusive proton production.
NASA Astrophysics Data System (ADS)
Schultz, D. R.; Ovchinnikov, S. Yu; Stancil, P. C.; Zaman, T.
2016-04-01
Updating and extending previous work (Krstić and Schultz 1999 J. Phys. B: At. Mol. Opt. Phys. 32 3458 and other references) comprehensive calculations were performed for elastic scattering and charge transfer in proton—atomic hydrogen collisions. The results, obtained for 1301 collision energies in the center-of-mass energy range of 10-4-104 eV, are provided for integral and differential cross sections relevant to transport modeling in astrophysical and other plasma environments, and are made available through a website. Use of the data is demonstrated through a Monte Carlo transport simulation of solar wind proton propagation through atomic hydrogen gas representing a simple model of the solar wind interaction with heliospheric neutrals.
NASA Astrophysics Data System (ADS)
Schultz, D. R.; Ovchinnikov, S. Yu; Stancil, P. C.; Zaman, T.
2016-04-01
Updating and extending previous work (Krstić and Schultz 1999 J. Phys. B: At. Mol. Opt. Phys. 32 3458 and other references) comprehensive calculations were performed for elastic scattering and charge transfer in proton—atomic hydrogen collisions. The results, obtained for 1301 collision energies in the center-of-mass energy range of 10‑4–104 eV, are provided for integral and differential cross sections relevant to transport modeling in astrophysical and other plasma environments, and are made available through a website. Use of the data is demonstrated through a Monte Carlo transport simulation of solar wind proton propagation through atomic hydrogen gas representing a simple model of the solar wind interaction with heliospheric neutrals.
Proton-Nucleus Scattering Approximations and Implications for LHC Crystal Collimation
Noble, Robert; /SLAC
2010-06-07
In particle accelerators, scattered protons with energies close to the incident particles may travel considerable distances with the beam before impacting on accelerator components downstream. To analyze such problems, angular deflection and energy loss of scattered particles are the main quantities to be simulated since these lead to changes in the beam's phase space distribution and particle loss. Simple approximations for nuclear scattering processes causing limited energy loss to high-energy protons traversing matter are developed which are suitable for rapid estimates and reduced-description Monte Carlo simulations. The implications for proton loss in the Large Hadron Collider due to nuclear scattering on collimation crystals are discussed.
NASA Technical Reports Server (NTRS)
Wilson, J. W.
1972-01-01
The exact nucleon-deuteron elastic single scattering integral was calculated numerically in order to evaluate errors in sticking factor approximations. A similar analysis made by using S wave separable potentials concluded that errors for these approximations were negligible except near backward angles where they were found to be about 10 percent.
Backward elastic light scattering of malaria infected red blood cells
NASA Astrophysics Data System (ADS)
Lee, Seungjun; Lu, Wei
2011-08-01
We investigated the backward light scattering pattern of healthy and malaria (Plasmodium falciparum) parasitized red blood cells. The spectrum could clearly distinguish between predominant ring stage infected blood cells and healthy blood cells. Further, we found that infected samples mixed with different stages of P. falciparum showed different signals, suggesting that even variance in parasite stages could also be detected by the spectrum. These results together with the backward scattering technique suggest the potential of non-invasive diagnosis of malaria through light scattering of blood cells near the surface of human body, such as using eyes or skin surface.
Coupled channel effect in elastic scattering and fusion for 6,7Li+28Si
NASA Astrophysics Data System (ADS)
Sinha, Mandira; Roy, Subinit; Basu, P.; Majumdar, H.; Santra, S.; Parkar, V. V.; Golda, K. S.; Kailas, S.
2011-10-01
The fusion excitation and elastic angular distribution were measured for 6,7Li+28Si from below to above Coulomb barrier (≤ 3Vb) energies. The barrier distribution derived from the fusion data was found to be broad and asymmetric at the sub-barrier region, compared to 1D BPM estimation. Effect of rotational coupling on fusion was found to be not so dominant. Phenomenological optical potential parameters, with surface and volume type imaginary potentials, were obtained from f tting of elastic scattering data and energy dependence of real and imaginary surface strengths were investigated around the barrier. CDCC calculations considering only breakup of projectile were performed for 6,7Li+28Si with the elastic scattering data, using the code FRESCO. The effects of breakup of projectile on elastic cross section do not agree with the energy dependence of real and imaginary strength with volume type imaginary potential around the barrier.
Nonlinear coda wave analysis of hysteretic elastic behavior in strongly scattering media
NASA Astrophysics Data System (ADS)
Ouarabi, M. Ait; Boubenider, F.; Gliozzi, A. S.; Scalerandi, M.
2016-10-01
Strongly scattering elastic media, such as consolidated granular materials, respond to ultrasonic pulse excitations with a long response signal with peculiar properties. The portion of the signal at late times, termed coda, is due to multiple scattering. It contains information about the elastic properties of the material, and it has been proven to be very sensitive to small variations in the modulus. Here we propose a technique based on a nonlinear analysis of the coda of a signal, which might be applied to quantify the nonlinear elastic response in consolidated granular media exhibiting a hysteretic elastic behavior. The method proposed allows for an intrinsic definition of the reference signal which is normally needed for applying coda-based methods.
Elastic scattering and total reaction cross section of {sup 6}He+{sup 120}Sn
Faria, P. N. de; Lichtenthaeler, R.; Pires, K. C. C.; Lepine-Szily, A.; Guimaraes, V.; Mendes, D. R. Jr.; Barioni, A.; Morcelle, V.; Morais, M. C.; Camargo, O. Jr.; Alcantara Nunez, J.; Moro, A. M.; Arazi, A.; Rodriguez-Gallardo, M.; Assuncao, M.
2010-04-15
The elastic scattering of {sup 6}He on {sup 120}Sn has been measured at four energies above the Coulomb barrier using the {sup 6}He beam produced at the RIBRAS (Radioactive Ion Beams in Brasil) facility. The elastic angular distributions have been analyzed with the optical model and three- and four-body continuum-discretized coupled-channels calculations. The total reaction cross sections have been derived and compared with other systems of similar masses.
Elastic neutron scattering at 96 MeV from 12C and 208Pb
NASA Astrophysics Data System (ADS)
Klug, J.; Blomgren, J.; Ataç, A.; Bergenwall, B.; Hildebrand, A.; Johansson, C.; Mermod, P.; Nilsson, L.; Pomp, S.; Tippawan, U.; Elmgren, K.; Olsson, N.; Jonsson, O.; Prokofiev, A. V.; Renberg, P.-U.; Nadel-Turonski, P.; Dangtip, S.; Phansuke, P.; Österlund, M.; Le Brun, C.; Lecolley, J. F.; Lecolley, F. R.; Louvel, M.; Marie-Noury, N.; Schweitzer, C.; Eudes, Ph.; Haddad, F.; Lebrun, C.; Koning, A. J.; Bauge, E.; Delaroche, J. P.; Girod, M.; Ledoux, X.; Romain, P.; Madland, D. G.; Amos, K.; Deb, P. K.; Karataglidis, S.; Crespo, R.; Moro, A. M.
2003-03-01
A facility for detection of scattered neutrons in the energy interval 50 130 MeV, scattered nucleon detection assembly, has recently been installed at the 20 180 MeV neutron beam line of The Svedberg Laboratory, Uppsala. First results on elastic neutron scattering from 12C and 208Pb at 96 MeV incident neutron energy are presented. This experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. The results are compared with modern optical model predictions.
Evolution of Elastic X-ray Scattering in Laser-Shocked Warm Dense Li
Kugland, N L; Gregori, G; Bandyopadhyay, S; Brenner, C; Brown, C; Constantin, C; Glenzer, S H; Khattak, F; Kritcher, A L; Niemann, C; Otten, A; Pasley, J; Pelka, A; Roth, M; Spindloe, C; Riley, D
2009-06-02
We have studied the dynamics of warm dense Li with near-elastic x-ray scattering. Li foils were heated and compressed using shock waves driven by 4 ns long laser pulses. Separate 1 ns long laser pulses were used to generate a bright source of 2.96 keV Cl Ly-{alpha} photons for x-ray scattering, and the spectrum of scattered photons was recorded at a scattering angle of 120{sup o} using a HOPG crystal operated in the von Hamos geometry. A variable delay between the heater and backlighter laser beams measured the scattering time evolution. Comparison with radiation hydrodynamics simulations shows that the plasma is highly coupled during the first several nanoseconds, then relaxes to a moderate coupling state at later times. Near-elastic scattering amplitudes have been successfully simulated using the screened one-component plasma model. Our main finding is that the near-elastic scattering amplitudes are quite sensitive to the mean ionization state {bar Z}, and by extension to the choice of ionization model in the radiation-hydrodynamics simulations used to predict plasma properties within the shocked Li.
Elastic and inelastic scattering of positrons in gases and solids
NASA Technical Reports Server (NTRS)
Mcgowan, J. W.
1972-01-01
Three apparatuses were designed and built: The first, which is now operative, was designed to study the details of positron thermalization in solids and the subsequent emission of the low energy positrons from moderating foils; The second apparatus now under test is a positron bottle similar in design to an electron trap. It was built to store positrons at a fixed energy and to look at the number of stored positrons (storage time) as a function of a scattering gas in the vacuum chamber. The third apparatus is a crossed beam apparatus where positron-, alkali scattering will be studied. Much of the apparatus is now under test with electrons.
Hybrid Theory of Electron-Hydrogenic Systems Elastic Scattering
NASA Technical Reports Server (NTRS)
Bhatia, A. K.
2007-01-01
Accurate electron-hydrogen and electron-hydrogenic cross sections are required to interpret fusion experiments, laboratory plasma physics and properties of the solar and astrophysical plasmas. We have developed a method in which the short-range and long-range correlations can be included at the same time in the scattering equations. The phase shifts have rigorous lower bounds and the scattering lengths have rigorous upper bounds. The phase shifts in the resonance region can be used to calculate very accurately the resonance parameters.
Halos and rainbows: The elastic scattering of light exotic nuclei
Satchler, G.R.; Hussein, M.H.
1993-10-01
The scattering of an exotic light nucleus with a halo is compared with that of a normal nucleus. Four, sometimes opposing effects arising from the halo are identified. Semiclassical expressions are derived which embody these effects. The cases of {sup 11}Li and {sup 11}C scattering from {sup 12}C at E/A = 60 MeV are compared. We conclude that the {sup 11}Li differential cross sections are probably smaller than those for {sup 11}C, in agreement with recent analyses of the measurements.
Myelin basic protein reduces molecular motions in DMPA, an elastic neutron scattering study
NASA Astrophysics Data System (ADS)
Natali, F.; Gliozzi, A.; Rolandi, R.; Cavatorta, P.; Deriu, A.; Fasano, A.; Riccio, P.
2001-07-01
We have studied the effect of physiological amounts of myelin basic protein (MBP) on pure dimyristoyl L- α-phosphatidic acid (DMPA) vesicles using the elastic neutron scattering technique. Elastic scans have been performed in a wide temperature range (20-300 K). In the lower temperature region the behaviour of the integrated elastic intensity was the typical one of harmonic systems. The analysis of the Q and T dependence performed in terms of an asymmetric double well potential clearly showed that the effect of the protein consisted in a significant reduction of the conformational mobility of the DMPA bilayers and in the stabilisation of the membrane.
Bigio, I.J.; Boyer, J.; Johnson, T.M.; Lacey, J.; Mourant, J.R.; Conn, R.; Bohorfoush, A.
1994-10-01
The Los Alamos National Laboratory has continued the development of the Optical Biopsy System (OBS) for noninvasive, real-time in situ diagnosis of tissue pathologies. Our clinical studies have expanded since the last Biomedical Optics Europe conference (Budapest, September 1993), and we report here on the latest results of clinical tests in gastrointestinal tract. The OBS invokes a unique approach to optical diagnosis of tissue pathologies based on the elastic scattering properties, over a wide range of wavelengths, of the tissue. The use of elastic scattering as the key to optical tissue diagnostics in the OBS is based on the fact that many tissue pathologies, including a majority of cancer forms, manifest significant architectural changes at the cellular and sub-cellular level. Since the cellular components that cause elastic scattering have dimensions typically on the order of visible to near-IR wavelengths, the elastic (Mie) scattering properties will be wavelength dependent. Thus, morphology and size changes can be expected to cause significant changes in an optical signature that is derived from the wavelength-dependence of elastic scattering. The OBS employs a small fiberoptic probe that is amenable to use with any endoscope or catheter, or to direct surface examination. The probe is designed to be used in optical contact with the tissue under examination and has separate illuminating and collecting fibers. Thus, the light that is collected and transmitted to the analyzing spectrometer must first scatter through a small volume of the tissue before entering the collection fiber(s). Consequently, the system is also sensitive to the optical absorption spectrum of the tissue, over an effective operating range of <300 to 950 nm, and such absorption adds valuable complexity to the scattering spectral signature.
Elastic electron scattering in krypton in the energy range from 5 to 10 eV
Linert, Ireneusz; Mielewska, Brygida; Zubek, Mariusz; King, George C.
2010-01-15
Differential cross sections for elastic electron scattering in krypton have been measured at the energies of 5,7.5, and 10 eV over the scattering angle range from 30 deg. to 180 deg. The measurements for backward scattering employed the magnetic angle-changing technique. These differential cross sections have been integrated to yield the elastic integral and momentum transfer cross sections at the above energies. These new results are compared with the most recent measurements and calculations of the respective cross sections in krypton. The dependence of the differential cross sections on atomic polarizability of the heavier rare gas atoms argon, krypton, and xenon has also been investigated over the electron energy range 5-30 eV and for forward, backward, and intermediate scattering angles.
NASA Astrophysics Data System (ADS)
Li, Xiao-Hua; Guo, Wen-Jun; Li, Bao-An; Chen, Lie-Wen; Fattoyev, Farrukh J.; Newton, William G.
2015-04-01
The neutron-proton effective mass splitting in asymmetric nucleonic matter of isospin asymmetry δ and normal density is found to be mn-p* ≡ (mn* - mp*) / m = (0.41 ± 0.15) δ from analyzing globally 1088 sets of reaction and angular differential cross sections of proton elastic scattering on 130 targets with beam energies from 0.783 MeV to 200 MeV, and 1161 sets of data of neutron elastic scattering on 104 targets with beam energies from 0.05 MeV to 200 MeV within an isospin dependent non-relativistic optical potential model. It sets a useful reference for testing model predictions on the momentum dependence of the nucleon isovector potential necessary for understanding novel structures and reactions of rare isotopes.
Alkhazov, G. D.; Sarantsev, V. V.
2012-12-15
In order to clear up the sensitivity of the nucleus-nucleus scattering to the nuclear matter distributions in exotic halo nuclei, we have calculated differential cross sections for elastic scattering of the {sup 6}He and {sup 11}Li nuclei on several nuclear targets at the energy of 0.8 GeV/nucleon with different assumed nuclear density distributions in {sup 6}He and {sup 11}Li.
sup 4 He- sup 4 He elastic scattering and variational wave functions
Usmani, A.A.; Ahmad, I. ); Usmani, Q.N. )
1992-01-01
We calculate differential cross sections for {sup 4}He-{sup 4}He elastic scattering at 4.32 GeV/{ital c} in the framework of Glauber multiple scattering theory using correlated variational wave functions as given by the two-nucleon Urbana {ital v}{sub 14} potential and the spin-isospin averaged Melfleit-Tjon force {ital V}. These wave functions are found to give fairly satisfactory results.
Doster, W.; Nakagawa, H.; Appavou, M. S.
2013-07-28
Numerous neutron scattering studies of bio-molecular dynamics employ a qualitative analysis of elastic scattering data and atomic mean square displacements. We provide a new quantitative approach showing that the intensity at zero energy exchange can be a rich source of information of bio-structural fluctuations on a pico- to nano-second time scale. Elastic intensity scans performed either as a function of the temperature (back-scattering) and/or by varying the instrumental resolution (time of flight spectroscopy) yield the activation parameters of molecular motions and the approximate structural correlation function in the time domain. The two methods are unified by a scaling function, which depends on the ratio of correlation time and instrumental resolution time. The elastic scattering concept is illustrated with a dynamic characterization of alanine-dipeptide, protein hydration water, and water-coupled protein motions of lysozyme, per-deuterated c-phycocyanin (CPC) and hydrated myoglobin. The complete elastic scattering function versus temperature, momentum exchange, and instrumental resolution is analyzed instead of focusing on a single cross-over temperature of mean square displacements at the apparent onset temperature of an-harmonic motions. Our method predicts the protein dynamical transition (PDT) at T{sub d} from the collective (α) structural relaxation rates of the solvation shell as input. By contrast, the secondary (β) relaxation enhances the amplitude of fast local motions in the vicinity of the glass temperature T{sub g}. The PDT is specified by step function in the elastic intensity leading from elastic to viscoelastic dynamic behavior at a transition temperature T{sub d}.
NASA Astrophysics Data System (ADS)
Doster, W.; Nakagawa, H.; Appavou, M. S.
2013-07-01
Numerous neutron scattering studies of bio-molecular dynamics employ a qualitative analysis of elastic scattering data and atomic mean square displacements. We provide a new quantitative approach showing that the intensity at zero energy exchange can be a rich source of information of bio-structural fluctuations on a pico- to nano-second time scale. Elastic intensity scans performed either as a function of the temperature (back-scattering) and/or by varying the instrumental resolution (time of flight spectroscopy) yield the activation parameters of molecular motions and the approximate structural correlation function in the time domain. The two methods are unified by a scaling function, which depends on the ratio of correlation time and instrumental resolution time. The elastic scattering concept is illustrated with a dynamic characterization of alanine-dipeptide, protein hydration water, and water-coupled protein motions of lysozyme, per-deuterated c-phycocyanin (CPC) and hydrated myoglobin. The complete elastic scattering function versus temperature, momentum exchange, and instrumental resolution is analyzed instead of focusing on a single cross-over temperature of mean square displacements at the apparent onset temperature of an-harmonic motions. Our method predicts the protein dynamical transition (PDT) at Td from the collective (α) structural relaxation rates of the solvation shell as input. By contrast, the secondary (β) relaxation enhances the amplitude of fast local motions in the vicinity of the glass temperature Tg. The PDT is specified by step function in the elastic intensity leading from elastic to viscoelastic dynamic behavior at a transition temperature Td.
Correlation effects in elastic e-N2 scattering
NASA Technical Reports Server (NTRS)
Huo, Winifred M.; Lima, Marco A. P.; Gibson, Thomas L.; Mckoy, Vincent
1987-01-01
The Schwinger multichannel formulation has been applied to study the role of electron correlation in low-energy e-N2 scattering. For the five nonresonant partial-wave channels studied here, angular correlation is found to be much more important than radial correlation. The calculated total and differential cross sections agree well with experiment except for the differential cross sections at 1.5 eV.
Measurement of muon neutrino quasi-elastic scattering on carbon
Aguilar-Arevalo, A.A.; Bazarko, A.O.; Brice, S.J.; Brown, B.C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J.M.; Cox, D.C.; Curioni, A.; Djurcic, Z.; /Alabama U. /Bucknell U. /Cincinnati U. /Colorado U. /Columbia U. /Embry-Riddle Aeronautical U. /Fermilab /Indiana U. /Los Alamos /Louisiana State U. /Michigan U.
2007-06-01
Low energy (200 < E{sub v} < 2000 MeV) neutrino oscillation experiments, including MiniBooNE, require a model of charged current quasi-elastic (CCQE) neutrino interactions to predict signal samples. Using a high-statistics sample of muon neutrino CCQE events, MiniBooNE finds that a simple Fermi gas model, with appropriate adjustments, accurately characterizes the CCQE events observed in a carbon-based detector. The extracted parameters include an effective axial mass, M{sub A} = 1.23 {+-} 0.20 GeV, used to describe the four-momentum dependence of the axial-vector form factor of the nucleon; and a Pauli-suppression parameter, {kappa} = 1.019 {+-} 0.011.
Residual-stress characterization by use of elastic-wave-scattering measurements
Domany, E.; Gubernatis, J.E.
1982-01-01
The presence of a state of residual stress in a material can impair its structural quality by adversely affecting its elastic limit, yield point, etc. In this paper we derive the appropriate equations for the use of elastic waves to probe an inhomogeneous state of residual stress. As in other treatments of ultrasonic residual stress measurement, we start with nonlinear effects and require knowledge of third order elastic constants. Unlike other treatments, which relate these nonlinear effects to small relative changes in propagation speed of an incident wave, we identify these effects as a source of scattering of the incident wave. Like other treatments, one difficulty with ultrasonic residual stress measurements is separating small residual stress effects from other effects. However, we will give an example of at least one class of problems where this separation appears possible using our approach. It is demonstrated that elastic wave propagation in the presence of non-uniform residual stress can be viewed as a scattering problem. One should note that in various limits, such as that of short wavelength, this scattering problem (as well as any other) can be treated by optical methods (ray bendings, diffraction, etc.). The special features of a scattering situation are expected to be important for smaller wavelengths, and therefore their experimental observability is questionable, and can be resolved only by careful and thorough measurements.
Search for Elastic Coherent Neutrino Scattering off Atomic Nuclei at the Kalinin Nuclear Power Plant
NASA Astrophysics Data System (ADS)
Akimov, D. Yu.; Belov, V. A.; Bolozdynya, A. I.; Burenkov, A. A.; Efremenko, Yu. V.; Etenko, A. V.; Kaplin, V. A.; Khromov, A. V.; Konovalov, A. M.; Kovalenko, A. G.; Kumpan, A. V.; Melikyan, Yu. A.; Rudik, D. G.; Sosnovtsev, V. V.
We propose to detect and study neutrino neutral elastic coherent scattering off atomic nuclei with two-phase emission detector with liquid xenon as a target medium. One of the possible experimental site is a Kalinin Nuclear Power Plant (KNPP) situated in the Russian Federation. In this paper we discuss the design of the detector and expected signals and background for this site.
Elastic scattering of {sup 6}He and {sup 7}Be on a {sup 9}Be target
Pires, K. C. C.; Lichtenthaeler, R.; Mukha, I.; Moro, A. M.; Gomez-Camacho, J.
2010-04-26
The elastic scattering data for the {sup 6}He+{sup 9}Be and {sup 7}Be+{sup 9}Be reactions, measured at E{sub lab} = 16.2 MeV and E{sub lab} = 23.7 MeV respectively, are presented and analyzed using the optical model and coupled-channels formalisms.
Single-collision approximation for p{sup 3}-He elastic scattering at low energy
Abusini, M.
2009-06-15
A theoretical approach to studying four-body reactions of p{sup 3}-He elastic scattering that takes consistently into account the single-collision mechanism is reported. The theoretical results obtained by this method were compared with experimental data, and the agreement is found to be quite satisfactory.
NASA Astrophysics Data System (ADS)
Fanelli, C.; Cisbani, E.; Hamilton, D. J.; Salmé, G.; Wojtsekhowski, B.; Ahmidouch, A.; Annand, J. R. M.; Baghdasaryan, H.; Beaufait, J.; Bosted, P.; Brash, E. J.; Butuceanu, C.; Carter, P.; Christy, E.; Chudakov, E.; Danagoulian, S.; Day, D.; Degtyarenko, P.; Ent, R.; Fenker, H.; Fowler, M.; Frlez, E.; Gaskell, D.; Gilman, R.; Horn, T.; Huber, G. M.; de Jager, C. W.; Jensen, E.; Jones, M. K.; Kelleher, A.; Keppel, C.; Khandaker, M.; Kohl, M.; Kumbartzki, G.; Lassiter, S.; Li, Y.; Lindgren, R.; Lovelace, H.; Luo, W.; Mack, D.; Mamyan, V.; Margaziotis, D. J.; Markowitz, P.; Maxwell, J.; Mbianda, G.; Meekins, D.; Meziane, M.; Miller, J.; Mkrtchyan, A.; Mkrtchyan, H.; Mulholland, J.; Nelyubin, V.; Pentchev, L.; Perdrisat, C. F.; Piasetzky, E.; Prok, Y.; Puckett, A. J. R.; Punjabi, V.; Shabestari, M.; Shahinyan, A.; Slifer, K.; Smith, G.; Solvignon, P.; Subedi, R.; Wesselmann, F. R.; Wood, S.; Ye, Z.; Zheng, X.
2015-10-01
Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θcmp=70 ° . The longitudinal transfer KLL, measured to be 0.645 ±0.059 ±0.048 , where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ˜3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.
Quasi-elastic light scattering from structured particles.
Chen, S H; Holz, M; Tartaglia, P
1977-01-01
We present a formulation by which the scattered field correlation function of a nonstationary structured particle can be calculated. Specifically, we consider the case of micron-size bacteria, where the Rayleigh- Gans-Debye approximation may be used to evaluate the correlation function. We show that the width of the intensity correlation spectrum (as measured, for example, by the photon correlation technique) exhibits I an oscillatory behavior which is characteristic of the interference pattern produced by the internal structure. Two cases are of interest: diffusion and motility are considered in detail, and some evidence of the predicted behavior is shown from the photon correlation measurement of E. coli bacteria. PMID:20168450
Elastic Scattering of Low-Energy Electrons byTetrahydrofuran
Trevisan, Cynthia S.; Orel, Ann E.; Rescigno, Thomas N.
2006-05-09
We present the results of ab initio calculations for elasticelectron scattering by tetrahydrofuran (THF) using the complex Kohnvariational method. We carried out fixed-nuclei calculations at theequilibrium geometry of the target molecule for incident electronenergies up to 20 eV. The calculated momentum transfer cross sectionsclearly reveal the presence of broad shape resonance behavior in the 8-10eV energy range, in agreement with recent experiments. The calculateddifferential cross sections at 20 eV, which include the effects of thelong-range electron-dipole interaction, are alsofound to be in agreementwith the most recent experimental findings.
TI-59 model for elastic scattering of heavy nuclei. Part 2
NASA Astrophysics Data System (ADS)
Strutinsky, V. M.
1981-06-01
It is shown that the presence of relatively small irregular components in the particle elastic scattering amplitudes may play a determining role in the scattering at the backward angles. The general features of the calculated angular distributions agree with the trends of the experimental data. A new explanation of the so-called backward-angle resonances is suggested. The fluctuating features of the scattering amplitudes are animated by means of the random number generator of the desk calculator Texas-Instruments-59 used in the computations.
Investigation of condensed matter by means of elastic thermal-neutron scattering
NASA Astrophysics Data System (ADS)
Abov, Yu. G.; Dzheparov, F. S.; Elyutin, N. O.; Lvov, D. V.; Tyulyusov, A. N.
2016-07-01
The application of elastic thermal-neutron scattering in investigations of condensed matter that were performed at the Institute for Theoretical and Experimental Physics is described. An account of diffraction studies with weakly absorbing crystals, including studies of the anomalous-absorption effect and coherent effects in diffuse scattering, is given. Particular attention is given to exposing the method of multiple small-angle neutron scattering (MSANS). It is shown how information about matter inhomogeneities can be obtained by this method on the basis of Molière's theory. Prospects of the development of this method are outlined, and MSANS theory is formulated for a high concentration of matter inhomogeneities.
Djurado, David; Bée, Marc; Sniechowski, Maciej; Howells, Spencer; Rannou, Patrice; Pron, Adam; Travers, J P; Luzny, Wojciech
2005-03-21
Proton dynamics in films of poly(aniline) "plastdoped" with di-esters of sulfophthalic (or sulfosuccinic) acids have been investigated by using quasi-elastic neutron scattering techniques. A broad time range (10(-13)-10(-9) s) has been explored by using four different spectrometers. In this time range, the dynamics is exclusively due to protons attached to the flexible tails of the counter-ions. A model of limited diffusion in spheres whose radii are distributed in size gives a realistic view of the geometry of molecular motions. However, it is found that the characteristic times of these motions are widely distributed over several orders of magnitude. The time decay of the intermediate scattering function is well described by a time power law. This behaviour is qualitatively discussed in connection with the structure of the systems and by comparison with other so-called complex systems.
Rhodopsin Photoactivation Dynamics Revealed by Quasi-Elastic Neutron Scattering
NASA Astrophysics Data System (ADS)
Bhowmik, Debsindhu; Shrestha, Utsab; Perera, Suchhithranga M. C. D.; Chawla, Udeep; Mamontov, Eugene; Brown, Michael; Chu, Xiang-Qiang
2015-03-01
Rhodopsin is a G-protein-coupled receptor (GPCR) responsible for vision. During photoactivation, the chromophore retinal dissociates from protein yielding the opsin apoprotein. What are the changes in protein dynamics that occur during the photoactivation process? Here, we studied the microscopic dynamics of dark-state rhodopsin and the ligand-free opsin using quasielastic neutron scattering (QENS). The QENS technique tracks individual hydrogen atom motion because of the much higher neutron scattering cross-section of hydrogen than other atoms. We used protein with CHAPS detergent hydrated with heavy water. The activation of proteins is confirmed at low temperatures up to 300 K by mean-square displacement (MSD) analysis. The QENS experiments at temperatures ranging from 220 K to 300 K clearly indicate an increase in protein dynamic behavior with temperature. The relaxation time for the ligand-bound protein rhodopsin is faster compared to opsin, which can be correlated with the photoactivation. Moreover, the protein dynamics are orders of magnitude slower than the accompanying CHAPS detergent, which unlike protein, manifests localized motions.
Bigio, I.J.; Loree, T.R.; Mourant, J.; Shimada, T.; Story-Held, K.; Glickman, R.D.; Conn, R.
1993-08-01
A non-invasive diagnostic tool that could identify malignancy in situ and in real time would have a major impact on the detection and treatment of cancer. We have developed and are testing early prototypes of an optical biopsy system (OBS) for detection of cancer and other tissue pathologies. The OBS invokes a unique approach to optical diagnosis of tissue pathologies based on the elastic scattering properties, over a wide range of wavelengths, of the microscopic structure of the tissue. The use of elastic scattering as the key to optical tissue diagnostics in the OBS is based on the fact that many tissue pathologies, including a majority of cancer forms, manifest significant architectural changes at the cellular and sub-cellular level. Since the cellular components that cause elastic scattering have dimensions typically on the order of visible to near-IR wavelengths, the elastic (Mie) scattering properties will be strongly wavelength dependent. Thus, morphology and size changes can be expected to cause significant changes in an optical signature that is derived from the wavelength dependence of elastic scattering. The data acquisition and storage/display time with the OBS instrument is {approximately}1 second. Thus, in addition to the reduced invasiveness of this technique compared with current state-of-the-art methods (surgical biopsy and pathology analysis), the OBS offers the possibility of impressively faster diagnostic assessment. The OBS employs a small fiber-optic probe that is amenable to use with any endoscope, catheter or hypodermic, or to direct surface examination (e.g. as in skin cancer or cervical cancer). It has been tested in vitro on animal and human tissue samples, and clinical testing in vivo is currently in progress.
Gerasimov, R. E. Fadin, V. S.
2015-01-15
An analysis of approximations used in calculations of radiative corrections to electron-proton scattering cross section is presented. We investigate the difference between the relatively recent Maximon and Tjon result and the Mo and Tsai result, which was used in the analysis of experimental data. We also discuss the proton form factors ratio dependence on the way we take into account radiative corrections.
Internal spin structure of the proton from high energy polarized e-p scattering
Hughes, V.W.; Baum, G.; Bergstroem, M.R.
1981-02-01
A review is given of experimental knowledge of the spin dependent structure functions of the proton, which is based on inclusive high energy scattering of longitudinal polarized electrons by longitudinally polarized protons in both the deep inelastic and resonance regions, and includes preliminary results from our most recent SLAC experiment. Implications for scaling, sum rules, models of proton structure, and the hyperfine structure interval in hydrogen are given. Possible future directions of research are indicated.
Monte Carlo simulations of elastic wave multiple scattering in polycrystalline media
NASA Astrophysics Data System (ADS)
Ghoshal, Goutam; Turner, Joseph A.
2005-09-01
The scattering of elastic waves in polycrystalline media is primarily due to the orientation distribution of the crystal axes of the grains. This scattering may be used to extract microstructural parameters of the material such as grain size and grain texture. In particular, diffuse ultrasonic backscatter measurements have been especially useful for extracting microstructural information. Diffuse backscatter is often modeled analytically under a single scattering assumption. Beyond single scattering, the elastic radiative transfer equation (RTE) governs the evolution of diffuse energy and includes all multiple scattering effects. In this presentation, a rigorous connection between the RTE theory and the backscatter experiments is discussed. Specific solutions are obtained for a specimen excited by a normally incident longitudinal wave. Results are compared with previous backscatter theories. In addition, numerical results are presented using Monte Carlo simulations including various levels of scattering to observe differences between single and multiple scattering solutions. The Monte Carlo solutions are based on the analogy between the RTE and the Boltzmann theory of gas. Relevant applications for materials of common interest are discussed. These results are anticipated to impact ultrasonic nondestructive evaluation of polycrystalline media. [Work supported by U.S. DOE.
Time-domain numerical simulations of multiple scattering to extract elastic effective wavenumbers
NASA Astrophysics Data System (ADS)
Chekroun, Mathieu; Le Marrec, Loïc; Lombard, Bruno; Piraux, Joël
2012-08-01
Elastic wave propagation is studied in a heterogeneous two-dimensional medium consisting of an elastic matrix containing randomly distributed circular elastic inclusions. The aim of this study is to determine the effective wavenumbers when the incident wavelength is similar to the radius of the inclusions. A purely numerical methodology is presented, with which the limitations usually associated with low scatterer concentrations can be avoided. The elastodynamic equations are integrated by a fourth-order time-domain numerical scheme. An immersed interface method is used to accurately discretize the interfaces on a Cartesian grid. The effective field is extracted from the simulated data, and signal-processing tools are used to obtain the complex effective wavenumbers. The numerical reference solution thus obtained can be used to check the validity of multiple scattering analytical models. The method is applied to the case of concrete. A parametric study is performed on longitudinal and transverse incident plane waves at various scatterer concentrations. The phase velocities and attenuations determined numerically are compared with predictions obtained with multiple scattering models, such as the Independent Scattering Approximation model, the Waterman-Truell model, and the more recent Conoir-Norris model.
Cross-Section Measurements for Elastic and Inelastic Scattering of Neutrons from Noble Gases
NASA Astrophysics Data System (ADS)
Macmullin, Sean; Kidd, Mary; Tornow, Werner; Howell, Calvin; Brown, Michael; Henning, Reyco
2010-11-01
Neutron backgrounds are a significant concern to experiments that attempt to directly detect Weakly Interacting Massive Particle (WIMP) dark matter. Recoil nuclei produced by neutron elastic scattering can mimic WIMP signatures. There is insufficient experimental data available for the scattering cross-sections of neutrons with noble gases (Ne, Ar, Xe), which are candidate target materials for such experiments. Neutron elastic and inelastic scattering from neon of natural abundance was investigated at the Triangle Universities Nuclear Laboratory at neutron energies relevant to (α,n) and low-energy spallation neutron backgrounds in these experiments. The differential cross-section was measured using a time-of-flight technique at neutron energies of 8.0 and 5.0 MeV. Details of the experimental technique and current status of measurements will be presented.
Modelling of nonlinear wave scattering in a delaminated elastic bar
Khusnutdinova, K. R.; Tranter, M. R.
2015-01-01
Integrity of layered structures, extensively used in modern industry, strongly depends on the quality of their interfaces; poor adhesion or delamination can lead to a failure of the structure. Can nonlinear waves help us to control the quality of layered structures? In this paper, we numerically model the dynamics of a long longitudinal strain solitary wave in a split, symmetric layered bar. The recently developed analytical approach, based on matching two asymptotic multiple-scales expansions and the integrability theory of the Korteweg–de Vries equation by the inverse scattering transform, is used to develop an effective semi-analytical numerical approach for these types of problems. We also employ a direct finite-difference method and compare the numerical results with each other, and with the analytical predictions. The numerical modelling confirms that delamination causes fission of an incident solitary wave and, thus, can be used to detect the defect. PMID:26730218
Cross-section for proton tritium scattering from 1.4 to 3.4 MeV at the laboratory angle of 165°
NASA Astrophysics Data System (ADS)
Xia, X. J.; Ding, W.; Zhang, B.; Long, X. G.; Luo, S. Z.; Peng, S. M.; Hutton, R.; Shi, L. Q.
2008-03-01
The elastic scattering cross-section for proton scattering from tritium was measured at a laboratory angle of 165° and over an incident proton energy range from 1.4 to 3.4 MeV. A thin solid target containing 1.62 × 1017 T atoms/cm2 was prepared by absorption of tritium into a film of titanium on aluminium foil backing. The cross-section increases almost linearly with decreasing energy in the higher energy region of 2-3.4 MeV. The currently measured cross-section data are compared with data available in the literature values and they show a similarly linear trend in a similar higher energy range. The maximum difference in the cross-section at almost the same scattering angle between current data and the previous results is no worse than 2.3%.
High Precision Measurement of the Proton Elastic Form Factor Ratio at Low Q2
Xiaohui Zhan
2009-12-01
A high precision measurement of the proton elastic form factor ratio µpGEp/GMp in the range Q2 = 0.3–0.7 GeV2/c2 was performed using recoil polarimetry in Jefferson Lab Hall A. In this low Q2 range, previous data from LEDEX [5] along with many fits and calculations [2, 3, 4] indicate substantial deviations of the ratio from unity. In this new measurement, with 80% polarized electron beam for 24 days, we are able to achieve <1% statistical uncertainty. Preliminary results are a few percent lower than expected from previous world data and fits, indicating a smaller GEp at this region. Beyond the intrinsic interest in nucleon structure, the improved form factor measurements also have implications for DVCS, determinations of the proton Zemach radius and strangeness form factors through parity violation experiments.
Towards a Precision Measurement of Parity-Violating e-p Elastic Scattering at Low Momentum Transfer
Pan, Jie
2012-01-01
The goal of the Q-weak experiment is to make a measurement of the proton's weak charge Q_{W}^{p} = 1 - 4 sin^{2}(θ_{W2(θW2(θWWp by measuring the parity violating asymmetry in elastic electron-proton scattering at low momentum transfer Q2 = 0.026 (GeV/c)2 and forward angles (8 degrees). The anticipated size of the asymmetry, based on the SM, is about 230 parts per billion (ppb). With the proposed accuracy, the experiment may probe new physics beyond Standard Model at the TeV scale. This thesis focuses on my contributions to the experiment, including track reconstruction for momentum transfer determination of the scattering process, and the focal plane scanner, a detector I designed and built to measure the flux profile of scattered electrons on the focal plane of the Q-weak spectrometer to assist in the extrapolation of low beam current tracking results to high beam current. Preliminary results from the commissioning and the first run period of the Q-weak experiment are reported and discussed.}
Every, A G; Sumanya, C; Mathe, B A; Zhang, X; Comins, J D
2016-07-01
Surface Brillouin scattering of light allows the angular-dependent velocities of Rayleigh surface acoustic waves (SAW), pseudo-SAW and longitudinal lateral waves (L) on the surface of an opaque crystal to be measured, and the elastic constants thereby determined. Closed form expressions exist for the surface wave velocities in high symmetry directions on crystallographic symmetry planes, and these have been exploited in the past for obtaining the values of the elastic constants. This paper describes a procedure for obtaining an optimized set of elastic constants from SAW, pseudo-SAW and L velocities measured in arbitrary directions in the (001) and (110) surfaces of cubic crystals. It does so by affecting a linearization of the numerically determined angular-dependent SAW and pseudo-SAW velocities near the best fit, and using analytic expressions for the L velocity. The method also generates covariance ellipsoids, from which the uncertainties in the determined values of the elastic constants can be read off. The method is illustrated using surface Brillouin scattering data to obtain the room-temperature elastic constants C11, C12 and C44 of the cubic crystals VC0.75 and Rh3Nb.
NASA Technical Reports Server (NTRS)
Tanaka, H.; Srivastava, S. K.; Chutjian, A.
1978-01-01
Using a crossed electron beam-molecular beam scattering geometry and a relative-flow technique, ratios of elastic differential cross sections of CO to those of He have been measured at electron impact energies of 3, 5, 7.5, 9.9, 15, 20, 30, 50, 75, and 100 eV. At each energy, an angular range of 15 to 130 deg has been covered. These ratios have been multiplied by previously known He elastic differential cross sections to obtain elastic differential cross sections for CO. Since pure rotational excitations were not resolved, the elastic differential cross sections are a sum of elastic and pure rotational excitations at room temperature. From a knowledge of differential cross sections (DCS), integral and momentum transfer cross sections have been calculated. Both the DCS and integral cross sections are compared at 50, 75, and 100 eV to a recent two-potential theory of e-molecule scattering. Present results show that the isoelectronic molecules CO and N2 have very similar magnitudes and shapes of their differential cross sections.
Ultracold Three-body Elastic Scattering in the Adiabatic Hyperspherical Representation
NASA Astrophysics Data System (ADS)
Colussi, Victor; D'Incao, Jose; Greene, Chris; Holland, Murray
2016-05-01
In the past few years, advances in ultracold quantum gases together with the ability to control interatomic interactions have opened up important questions related to three-body contributions to collective phenomena observables. In order to theoretically understand such contributions one needs to explore the three-body elastic scattering problem, which is fundamentally different than its two-body counterpart. The main difficulty is in the necessity to determine contributions to three-body scattering that originate from multiple scattering events where two atoms interact while the third spectates. These contributions must be subtracted out in order to determine scattering events that are truly of a three-body nature, i.e., collision events in which all three atoms participate. Here, we study this problem in the adiabatic hyperspherical representation and identify how unwanted two-body scattering events manifest in this picture. This opens up ways to develop a simple procedure capable of extracting truly three-body contributions to elastic scattering. This work was supported by the U. S. National Science Foundation.
Ono, M.; Wada, K.; Kitada, T.
2012-07-01
Simplified treatment of resonance elastic scattering model considering thermal motion of heavy nuclides and the energy dependence of the resonance cross section was implemented into NJOY [1]. In order to solve deterministic slowing down equation considering the effect of up-scattering without iterative calculations, scattering kernel for heavy nuclides is pre-calculated by the formula derived by Ouisloumen and Sanchez [2], and neutron spectrum in up-scattering term is expressed by NR approximation. To check the verification of the simplified treatment, the treatment is applied to U-238 for the energy range from 4 eV to 200 eV. Calculated multi-group capture cross section of U-238 is greater than that of conventional method and the increase of the capture cross sections is remarkable as the temperature becomes high. Therefore Doppler coefficient calculated in UO{sub 2} fuel pin is calculated more negative value than that on conventional method. The impact on Doppler coefficient is equivalent to the results of exact treatment of resonance elastic scattering reported in previous studies [2-7]. The agreement supports the validation of the simplified treatment and therefore this treatment is applied for other heavy nuclide to evaluate the Doppler coefficient in MOX fuel. The result shows that the impact of considering thermal agitation in resonance scattering in Doppler coefficient comes mainly from U-238 and that of other heavy nuclides such as Pu-239, 240 etc. is not comparable in MOX fuel. (authors)
Velocity-dependent optical potential for neutron elastic scattering from 1 p -shell nuclei
NASA Astrophysics Data System (ADS)
Ghabar, I. N.; Jaghoub, M. I.
2015-06-01
Background: The conventional optical model is quite successful in describing the nucleon elastic scattering data from medium and heavy nuclei. However, its success in describing the light 1 p -shell nuclei is somewhat limited. The velocity-dependent optical potential resulted in a significant improvement in describing the elastic angular distributions for light nuclei in the low energy region. Purpose: To extend the formalism of the velocity-dependent potential to higher energies, and to assess its importance in describing neutron elastic scattering data from light 1 p -shell nuclei at high energies. Method: We fit the angular distribution data for neutron elastic scattering from 12C and 16O using (i) the velocity-dependent optical potential and (ii) the conventional optical potential. The results of the two models are then compared. At low energies, we compare our angular distribution fits with the fits of other works that exist in the literature. Furthermore, the total integrated cross sections in addition to the analyzing power are calculated using the velocity-dependent optical potential and compared to the experimental data. Results: The velocity-dependent potential resulted in significant improvements in describing the angular distributions particularly in the large-angle scattering region and for certain energy ranges. This model is important where the experimental data show structural effects from nuclear surface deformations, which are important in light nuclei. Furthermore, the calculated total elastic cross sections and analyzing power are in good agreement with the experimental data. Conclusions: The velocity-dependent potential gives rise to surface-peaked real terms in the optical model. Such terms account, at least partly, for the structural effects seen in the angular distribution data. The energy range over which the surface terms are needed is found to depend on the target nucleus. Other works that have introduced real surface terms in the optical
Fanelli, Cristiano V.
2015-10-06
Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The WACS polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θPcm = 70°. The longitudinal transfer KLL, measured to be 0.645 ± 0.059 ± 0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton.more » However, the observed value is ~3 times larger than predicted by the GPD-based calculations, which indicates a significant unknown contribution to the scattering amplitude.« less
Fanelli, Cristiano V.
2015-10-06
Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The WACS polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θ^{P}_{cm} = 70°. The longitudinal transfer K_{LL}, measured to be 0.645 ± 0.059 ± 0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ~3 times larger than predicted by the GPD-based calculations, which indicates a significant unknown contribution to the scattering amplitude.
Model independent extraction of the proton magnetic radius from electron scattering
NASA Astrophysics Data System (ADS)
Epstein, Zachary; Paz, Gil; Roy, Joydeep
2014-10-01
We combine constraints from analyticity with experimental electron-proton scattering data to determine the proton magnetic radius without model-dependent assumptions on the shape of the form factor. We also study the impact of including electron-neutron scattering data, and ππ→NN ¯ data. Using representative data sets we find for a cut of Q2≤0.5 GeV2, rMp=0.91-0.06+0.03±0.02 fm using just proton scattering data; rMp=0.87-0.05+0.04±0.01 fm adding neutron data; and rMp=0.87-0.02+0.02 fm adding ππ data. We also extract the neutron magnetic radius from these data sets obtaining rMn=0.89-0.03+0.03 fm from the combined proton, neutron, and ππ data.
H-He elastic scattering at low energies: Contribution of nonzero partial waves
Sinha, Prabal K.; Ghosh, A.S.
2005-01-01
The present study reports the nonzero partial wave elastic cross sections together with s-wave results for the scattering of an antihydrogen atom off a gaseous helium target at thermal energies (up to 10{sup -2} a.u.). We have used a nonadiabatic atomic orbital method having different basis sets to investigate the system. The consideration of all the significant partial waves (up to J=24) reduces the oscillatory nature present in the individual partial wave cross section. The added elastic cross section is almost constant up to 10{sup -7} a.u. and then decreases steadily and very slowly with increasing energy.
Coupling between positronium formation and elastic positron-scattering channels in the rare gases
Jay, P. M.; Coleman, P. G.
2010-07-15
Measurements of elastic-scattering cross sections are presented for positron collisions with helium, neon, argon, krypton, and xenon around the threshold energy for positronium (Ps) formation. The elastic cross section falls slowly with increasing energy above the Ps formation threshold in helium and neon, whereas in argon, krypton, and xenon it exhibits an increase, which appears both more prominent and more sustained as the atomic number of the gas increases. It is proposed that this coupling is a result of an intermediate virtual Ps state that enhances branching into the (atom plus positron) final state.
Revisiting Elastic Scattering of D(n, n)D reaction
NASA Astrophysics Data System (ADS)
Stanoiu, M.; Canton, L.; Kozier, K. S.; Nankov, N.; Plompen, A.; Rao, R.; Roubtsov, D.; Rouki, C.; Svenne, J. P.
2010-04-01
Interest has risen recently concerning the angular distribution of neutron elastic scattering on deuterium at low incident energies. The main subject is the amount of backscatter at energies below 3.2 MeV observed in differential cross-section measurements and represented in various evaluations. These various angles of approach encompass fundamental nuclear-data measurements, three-body nuclear-theory calculations, evaluated nuclear -data libraries and associated data processing, and the simulation of critical experiments involving heav y water. A new theoretical approach on the basis of three -nucleon theory was made that resulte d in new angular distributions. At the GELINA neutron time-of-flight facility a new experimental setup was developed to measure elastic scattering of neutrons on deuterium in the energy range of interest. The technique proposed is complementary to the earlier works by detecting the scattered neutron instead of the recoiling deuterium. The setup is an array of two HPGe detectors, each with a 10B neutron-gamma converter. Preliminary GELINA findings using a C6D6 target indicate less backscatter than predicted by ENDF/B -VII.0, in contrast to the nuclear-theory results. It is expected that completion of the planned work will reduce the uncertainty of the energy-angle distributions for deuterium elastic scattering and contribute to an improved deuterium evaluation in a future release of ENDF/B -VII.
Revisiting Elastic Scattering of D(n, n)D reaction
Stanoiu, M.; Canton, L.; Kozier, K. S.; Rao, R.; Roubtsov, D.; Nankov, N.; Plompen, A.; Rouki, C.; Svenne, J. P.
2010-04-30
Interest has risen recently concerning the angular distribution of neutron elastic scattering on deuterium at low incident energies. The main subject is the amount of backscattering at energies below 3.2 MeV observed in differential cross-section measurements and represented in various evaluations. These various angles of approach encompass fundamental nuclear-data measurements, three-body nuclear-theory calculations, evaluated nuclear -data libraries and associated data processing, and the simulation of critical experiments involving heav y water. A new theoretical approach on the basis of three -nucleon theory was made that resulted in new angular distributions. At the GELINA neutron time-of-flight facility a new experimental setup was developed to measure elastic scattering of neutrons on deuterium in the energy range of interest. The technique proposed is complementary to the earlier works by detecting the scattered neutron instead of the recoiling deuterium. The setup is an array of two HPGe detectors, each with a {sup 10}B neutron-gamma converter. Preliminary GELINA findings using a C6D6 target indicate less backscatter than predicted by ENDF/B -VII.0, in contrast to the nuclear-theory results. It is expected that completion of the planned work will reduce the uncertainty of the energy-angle distributions for deuterium elastic scattering and contribute to an improved deuterium evaluation in a future release of ENDF/B -VII.
Power Output of Noise Sources Operating Near Elastic Scatterers of Finite Dimensions
NASA Astrophysics Data System (ADS)
TOMILINA, T. M.; BOBROVNITSKII, YU. I.; YASHKIN, V. B.; KOCHKIN, A. A.
1999-09-01
The problem of variation of the sound power output of noise sources due to reflecting boundaries and elastic scatterers is considered experimentally and numerically. In the laboratory experiment with a source of loudspeakers operating near a resonant scatterer, the increase in the radiated power obtained is about one hundred. An important role of the source near field in the power enhancement is shown. In computer simulation, a two-dimensional radiation problem for a circle vibrating near a finite elastic beam is studied. Most attention is paid to revealing physical mechanisms of the power output variations. It is shown that, for the source and elastic scatterer of finite dimensions, the radiated power can reach orders of magnitude of the free-field value. Especially, high-power amplification can be obtained at low frequencies for the sources that are poor radiators in free space, i.e., behave as multipoles of high order: presence of a scatterer or reflector makes such a source to be of monopole or dipole type. The results presented can be useful in better understanding sound generation mechanisms in complicated industrial noise sources.
Benedetto, Antonio; Kearley, Gordon J.
2016-01-01
A new type of neutron-scattering spectroscopy is presented that is designed specifically to measure dynamics in bio-systems that are difficult to obtain in any other way. The temporal information is largely model-free and is analogous to relaxation processes measured with dielectric spectroscopy, but provides additional spacial and geometric aspects of the underlying dynamics. Numerical simulations of the basic instrument design show the neutron beam can be highly focussed, giving efficiency gains that enable the use of small samples. Although we concentrate on continuous neutron sources, the extension to pulsed neutron sources is proposed, both requiring minimal data-treatment and being broadly analogous with dielectric spectroscopy, they will open the study of dynamics to new areas of biophysics. PMID:27703184
NASA Astrophysics Data System (ADS)
Benedetto, Antonio; Kearley, Gordon J.
2016-10-01
A new type of neutron-scattering spectroscopy is presented that is designed specifically to measure dynamics in bio-systems that are difficult to obtain in any other way. The temporal information is largely model-free and is analogous to relaxation processes measured with dielectric spectroscopy, but provides additional spacial and geometric aspects of the underlying dynamics. Numerical simulations of the basic instrument design show the neutron beam can be highly focussed, giving efficiency gains that enable the use of small samples. Although we concentrate on continuous neutron sources, the extension to pulsed neutron sources is proposed, both requiring minimal data-treatment and being broadly analogous with dielectric spectroscopy, they will open the study of dynamics to new areas of biophysics.
Measurement of high energy resolution inelastic proton scattering at and close to zero degrees
NASA Astrophysics Data System (ADS)
Tamii, A.; Fujita, Y.; Matsubara, H.; Adachi, T.; Carter, J.; Dozono, M.; Fujita, H.; Fujita, K.; Hashimoto, H.; Hatanaka, K.; Itahashi, T.; Itoh, M.; Kawabata, T.; Nakanishi, K.; Ninomiya, S.; Perez-Cerdan, A. B.; Popescu, L.; Rubio, B.; Saito, T.; Sakaguchi, H.; Sakemi, Y.; Sasamoto, Y.; Shimbara, Y.; Shimizu, Y.; Smit, F. D.; Tameshige, Y.; Yosoi, M.; Zenhiro, J.
2009-07-01
Measurements of inelastic proton scattering with high energy resolution at forward scattering angles including 0∘ are described. High-resolution halo-free beams were accelerated by the cyclotron complex at the Research Center for Nuclear Physics. Instrumental background events were minimized using the high-quality beam. The remaining instrumental background events were eliminated by applying a background subtraction method. As a result, clean spectra were obtained even for a heavy target nucleus such as Pb208. A high energy resolution of 20 keV (FWHM) and a scattering angle resolution of ±0.6∘ were achieved at an incident proton energy of 295 MeV.
Demonstration of a novel technique to measure two-photon exchange effects in elastic e±p scattering
Moteabbed, Maryam; Niroula, Megh; Raue, Brian A.; Weinstein, Lawrence B.
2013-08-30
The discrepancy between proton electromagnetic form factors extracted using unpolarized and polarized scattering data is believed to be a consequence of two-photon exchange (TPE) effects. However, the calculations of TPE corrections have significant model dependence, and there is limited direct experimental evidence for such corrections. The TPE contributions depend on the sign of the lepton charge in e±p scattering, but the luminosities of secondary positron beams limited past measurement at large scattering angles, where the TPE effects are believe to be most significant. We present the results of a new experimental technique for making direct e±p comparisons, which has the potential to make precise measurements over a broad range in Q^{2} and scattering angles. We use the Jefferson Laboratory electron beam and the Hall B photon tagger to generate a clean but untagged photon beam. The photon beam impinges on a converter foil to generate a mixed beam of electrons, positrons, and photons. A chicane is used to separate and recombine the electron and positron beams while the photon beam is stopped by a photon blocker. This provides a combined electron and positron beam, with energies from 0.5 to 3.2 GeV, which impinges on a liquid hydrogen target. The large acceptance CLAS detector is used to identify and reconstruct elastic scattering events, determining both the initial lepton energy and the sign of the scattered lepton. The data were collected in two days with a primary electron beam energy of only 3.3 GeV, limiting the data from this run to smaller values of Q^{2} and scattering angle. Nonetheless, this measurement yields a data sample for e±p with statistics comparable to those of the best previous measurements. We have shown that we can cleanly identify elastic scattering events and correct for the difference in acceptance for electron and positron scattering. Because we ran with only one polarity for the chicane, we are unable to study the
Demonstration of a novel technique to measure two-photon exchange effects in elastic e±p scattering
Moteabbed, Maryam; Niroula, Megh; Raue, Brian A.; Weinstein, Lawrence B.
2013-08-30
The discrepancy between proton electromagnetic form factors extracted using unpolarized and polarized scattering data is believed to be a consequence of two-photon exchange (TPE) effects. However, the calculations of TPE corrections have significant model dependence, and there is limited direct experimental evidence for such corrections. The TPE contributions depend on the sign of the lepton charge in e±p scattering, but the luminosities of secondary positron beams limited past measurement at large scattering angles, where the TPE effects are believe to be most significant. We present the results of a new experimental technique for making direct e±p comparisons, which has themore » potential to make precise measurements over a broad range in Q2 and scattering angles. We use the Jefferson Laboratory electron beam and the Hall B photon tagger to generate a clean but untagged photon beam. The photon beam impinges on a converter foil to generate a mixed beam of electrons, positrons, and photons. A chicane is used to separate and recombine the electron and positron beams while the photon beam is stopped by a photon blocker. This provides a combined electron and positron beam, with energies from 0.5 to 3.2 GeV, which impinges on a liquid hydrogen target. The large acceptance CLAS detector is used to identify and reconstruct elastic scattering events, determining both the initial lepton energy and the sign of the scattered lepton. The data were collected in two days with a primary electron beam energy of only 3.3 GeV, limiting the data from this run to smaller values of Q2 and scattering angle. Nonetheless, this measurement yields a data sample for e±p with statistics comparable to those of the best previous measurements. We have shown that we can cleanly identify elastic scattering events and correct for the difference in acceptance for electron and positron scattering. Because we ran with only one polarity for the chicane, we are unable to study the difference
Demonstration of a novel technique to measure two-photon exchange effects in elastic e±p scattering
NASA Astrophysics Data System (ADS)
Moteabbed, M.; Niroula, M.; Raue, B. A.; Weinstein, L. B.; Adikaram, D.; Arrington, J.; Brooks, W. K.; Lachniet, J.; Rimal, Dipak; Ungaro, M.; Afanasev, A.; Adhikari, K. P.; Aghasyan, M.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Cole, P. L.; Collins, P.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; Egiyan, H.; Fassi, L. El; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Fleming, J. A.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lewis, S.; Lu, H. Y.; MacCormick, M.; MacGregor, I. J. D.; Martinez, D.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moriya, K.; Moutarde, H.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Phelps, E.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Puckett, A. J. R.; Ripani, M.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S.; Strauch, S.; Tang, W.; Taylor, C. E.; Tian, Ye; Tkachenko, S.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.
2013-08-01
Background: The discrepancy between proton electromagnetic form factors extracted using unpolarized and polarized scattering data is believed to be a consequence of two-photon exchange (TPE) effects. However, the calculations of TPE corrections have significant model dependence, and there is limited direct experimental evidence for such corrections.Purpose: The TPE contributions depend on the sign of the lepton charge in e±p scattering, but the luminosities of secondary positron beams limited past measurement at large scattering angles, where the TPE effects are believe to be most significant. We present the results of a new experimental technique for making direct e±p comparisons, which has the potential to make precise measurements over a broad range in Q2 and scattering angles.Methods: We use the Jefferson Laboratory electron beam and the Hall B photon tagger to generate a clean but untagged photon beam. The photon beam impinges on a converter foil to generate a mixed beam of electrons, positrons, and photons. A chicane is used to separate and recombine the electron and positron beams while the photon beam is stopped by a photon blocker. This provides a combined electron and positron beam, with energies from 0.5 to 3.2 GeV, which impinges on a liquid hydrogen target. The large acceptance CLAS detector is used to identify and reconstruct elastic scattering events, determining both the initial lepton energy and the sign of the scattered lepton.Results: The data were collected in two days with a primary electron beam energy of only 3.3 GeV, limiting the data from this run to smaller values of Q2 and scattering angle. Nonetheless, this measurement yields a data sample for e±p with statistics comparable to those of the best previous measurements. We have shown that we can cleanly identify elastic scattering events and correct for the difference in acceptance for electron and positron scattering. Because we ran with only one polarity for the chicane, we are unable
Measurement of 25Al+p resonant elastic scattering for studying the 25Al(p,γ)26Si
NASA Astrophysics Data System (ADS)
Kwon, Y. K.; Lee, C. S.; Jung, H. S.; Moon, J. Y.; Lee, J. H.; Yun, C. C.; Kubono, S.; Yamaguchi, H.; Hashimoto, T.; Kahl, D.; Hayakawa, S.; Choi, Seonho; Kim, M. J.; Kim, Y. H.; Kim, Y. K.; Park, J. S.; Kim, E. J.; Moon, C.-B.; Teranishi, T.; Wakabayashi, Y.; Iwasa, N.; Yamada, T.; Togano, Y.; Kato, S.; Cherubini, S.; Rapisarda, G. G.
2012-11-01
Proton resonant states in 26Si have been studied by the resonant elastic scattering of 25Al+p with a 25Al radioactive ion beam at 2.863 MeV/nucleon bombarding a thick H2 gas target with the inverse kinematics method at the low-energy RI beam facility CRIB (CNS Radioactive Ion Beam separator), University of Tokyo. The properties of these resonance states are important to better determine the production rates of 25Al(p,γ)26Si reaction, which is one of the astrophysically important nuclear reactions to understand the production of the ground state of 26Al, the emitter of its characteristic 1.809-MeV gamma-ray, under the explosive stellar environments such as novae and X-ray bursts. In this work, several resonances above the proton threshold level have been observed with a high statistics and background free through a covered the range of excitation energies from Ex ~ 6.8 to 8.2 MeV.
Elastic /ital p//sub /up arrow//p/sub /up arrow// scattering between 240 and 470 MeV
Onel, Y.; Hausammann, R.; Heer, E.; Hess, R.; Lechanoine-Leluc, C.; Leo, W. R.; Rapin, D.; Jaccard, S.; Mango, S.
1989-07-01
The polarization parameter /ital P//sub /ital n/000/, the two-spin parameters/ital D//sub /ital n/0/ital n/0/, /ital K//sub /ital n/00/ital n//, /ital D//sub /ital s//prime/0/ital s/0/,/ital D//sub /ital s//prime/0/ital k/0/ and the three-spin parameters /ital M//sub /ital s//prime/0/ital sn//and /ital M//sub /ital s//prime/0/ital kn// have been measured for /ital pp/ elastic scatteringangles between 60/degree/ and 88/degree/ center of mass at 241 and 314 MeV incidentkinetic energies, and between 38/degree/ c.m. and 98/degree/ c.m. at 341, 366, and 398MeV. At 473 MeV, only /ital P//sub /ital n/000/ and /ital D//sub /ital s//prime/0/ital k/0/ weremeasured between 34/degree/ c.m. and 62/degree/ c.m. The experiment was performed at SINusing a polarized proton beam and a polarized butanol target. The polarizationof the scattered proton was analyzed in a carbon polarimeter. The influence ofthese high-precision data on the Saclay-Geneva phase-shift analysis isdiscussed.
Electron elastic scattering off A @C60 : The role of atomic polarization under confinement
NASA Astrophysics Data System (ADS)
Dolmatov, V. K.; Amusia, M. Ya.; Chernysheva, L. V.
2015-10-01
The present paper explores possible features of electron elastic scattering off endohedral fullerenes A @C60 . It focuses on how dynamical polarization of the encapsulated atom A by an incident electron might alter scattering off A @C60 compared to the static-atom-A case, as well as how the C60 confinement modifies the impact of atomic polarization on electron scattering compared to the free-atom case. The aim is to provide researchers with a "relative frame of reference" for understanding which part of the scattering processes could be due to electron scattering off the encapsulated atom and which could be due to scattering off the C60 cage. To meet the goal, the C60 cage is modeled by an attractive spherical potential of a certain inner radius, thickness, and depth which is a model used frequently in a great variety of fullerene studies to date. Then, the Dyson equation for the self-energy part of the Green's function of an incident electron moving in the combined field of an encapsulated atom A and C60 is solved in order to account for the impact of dynamical polarization of the encaged atom upon e +A @C60 scattering. The Ba@C60 endohedral is chosen as the case study. The impact is found to be significant, and its utterly different role compared to that in e +Ba scattering is unraveled.
Large Scale Simulations of Elastic Light Scattering by a Fast Discrete Dipole Approximation
NASA Astrophysics Data System (ADS)
Hoekstra, A. G.; Grimminck, M. D.; Sloot, P. M. A.
Simulation of Elastic Light Scattering from arbitrary shaped particles in the resonance region (i.e., with a dimension of several wavelengths of the incident light) is a long standing challenge. By employing the combination of a simulation kernel with low computational complexity, implemented on powerful High Performance Computing systems, we are now able to push the limits of simulation of scattering of visible light towards particles with dimensions up to 10 micrometers. This allows for the first time the simulation of realistic and highly relevant light scattering experiments, such as scattering from human red — or white blood cells, or scattering from large soot — or dust particles. We use the Discrete Dipole Approximation to simulate the light scattering process. In this paper we report on a parallel Fast Discrete Dipole Approximation, and we will show the performance of the resulting code, running under PVM on a 32-node Parsytec CC. Furthermore, as an example we present results of a simulation of scattering from human white blood cells. In a first approximation the Lymphocyte is modeled as a sphere with a spherical inclusion. We investigate the influence of the position of the inner sphere, modeling the nucleus of a Lymphocyte, on the light scattering signals.
Elastic diffuse scattering of neutrons in FeNi Invar alloys
NASA Astrophysics Data System (ADS)
Tsunoda, Y.; Hao, L.; Shimomura, S.; Ye, F.; Robertson, J. L.; Fernandez-Baca, J.
2008-09-01
Elastic diffuse scattering of neutrons was found around various Bragg-peak positions in FeNi Invar alloys. The diffuse scattering intensities depend on the temperature and Ni concentration. The intensities increase with decreasing temperature and decrease with increasing Ni concentration. The distribution of diffuse scattering intensity changes from peak to peak and is well explained by the formation of clusters with a lattice deformation consisting of a shear wave propagating along the ⟨110⟩ direction and with the ⟨1-10⟩ polarization vector. The ranges of temperature and Ni concentration, for which diffuse scattering is observed, coincide with those for which the Invar anomalies are observable. The origin of the clusters together with the lattice deformation and their role with regard to the Invar effects are discussed as well as the possibility of a precursor for the fcc-bcc martensitic transformation observed in FeNi alloys.
Boyer, J.; Mourant, J.R.; Bigio, I.J.
1995-05-01
An optical-fiber-coupled, elastic-scatter spectrometer has proven effective in discriminating between malignant and non-malignant tissue in the human bladder and gastrointestinal tract. The system injects broadband light into the tissue with an optical fiber and spectrally analyzes the returning light collected by an adjacent fiber. The collected photons have experienced multiple scattering events and therefore arrive at the analysis fiber after traveling varied paths.the diameter of the source fiber is comparable to its separation from the collection fiber. The diffusion model is inappropriate for this geometry; therefore, Monte Carlo simulations are used. In addition, the size of the scattering sites in tissue are expected to be of the same order as the excitation wavelengths, and Mie theory is expected to provide the best description of the scattering and extinction. The authors will present and compare the results of simulations and measurements of the elastic scatter signal for suspensions of latex spheres in hemoglobin solutions of varying concentrations.
Elastic scattering of low energy electrons in partially ionized dense semiclassical plasma
Dzhumagulova, K. N. Shalenov, E. O.; Ramazanov, T. S.
2015-08-15
Elastic scattering of electrons by hydrogen atoms in a dense semiclassical hydrogen plasma for low impact energies has been studied. Differential scattering cross sections were calculated within the effective model of electron-atom interaction taking into account the effect of screening as well as the quantum mechanical effect of diffraction. The calculations were carried out on the basis of the phase-function method. The influence of the diffraction effect on the Ramsauer–Townsend effect was studied on the basis of a comparison with results made within the effective polarization model of the Buckingham type.
Quasi-elastic light scattering studies of membrane motion in single red blood cells.
Tishler, R B; Carlson, F D
1987-01-01
Studies of red blood cells (RBCs) and RBC ghosts, using a quasi-elastic light scattering (QELS) microscope spectrometer, have identified the membrane as the primary source of the light scattering signal. This is the first report in which motion of the cell membrane has been demonstrated to be the primary source of the QELS signal from a cell. Cytoplasmic changes induced in the RBC by varying the osmotic strength of the medium were also detected using this technique. Comparison of the data from white blood cells (WBCs) with the RBC data demonstrated significant differences between different types of cells. PMID:3607216
Electron-He(+) P-wave Elastic Scattering and Photoabsorption in Two-electron Systems
NASA Technical Reports Server (NTRS)
Bhatia, A. K.
2006-01-01
In a previous paper [Bhatia, Phys. Rev. A 69,032714 (2004)], electron-hydrogen P-wave scattering phase shifts were calculated using the optical potential approach based on the Feshbach projection operator formalism. This method is now extended to the singlet and triplet electron-He(+) P-wave scattering in the elastic region. Phase shifts are calculated using Hylleraas-type correlation functions with up to 220 terms. Results are rigorous lower bounds to the exact phase shifts and they are compared to phase shifts obtained from the method of polarized orbitals and close-coupling calculations. The continuum functions calculated here are used to calculate photoabsorption cross sections. Photoionization cross sections of He and photodetachment cross sections of H(-) are calculated in the elastic region, i.e. leaving He(+) and H in their respective ground states, and compared with previous calculations. Radiative attachment rates are also calculated.
On the scatter ranges for the elastic moduli of random aggregates of general anisotropic crystals
NASA Astrophysics Data System (ADS)
Chinh, Pham Duc
2011-02-01
A randomly inhomogeneous material may have macroscopic properties (elasticity, conductivity) scattered over some uncertainty intervals, despite the idealistic uniqueness assumption of homogenization theory. Based on minimum energy principles and certain statistical isotropy-symmetry hypotheses, our partly third-order bounds on the effective properties of random polycrystals are expected to estimate those scatter ranges. Explicit expressions are given and calculated for the elastic moduli of the random aggregates of some known monoclinic and triclinic crystals, which yield results in agreement with those calculated for higher-symmetry crystals: the moduli are determinable within an accuracy of two or three significant digits in most cases. It is shown, however, that with some real-world exotic crystals the bounds may fall far apart, and further theoretical and experimental studies on them deserve attention.
Compton sources for the observation of elastic photon-photon scattering events
NASA Astrophysics Data System (ADS)
Micieli, D.; Drebot, I.; Bacci, A.; Milotti, E.; Petrillo, V.; Conti, M. Rossetti; Rossi, A. R.; Tassi, E.; Serafini, L.
2016-09-01
We present the design of a photon-photon collider based on conventional Compton gamma sources for the observation of elastic γ γ scattering. Two symmetric electron beams, generated by photocathodes and accelerated in linacs, produce two primary gamma rays through Compton backscattering with two high energy lasers. The elastic photon-photon scattering is analyzed by start-to-end simulations from the photocathodes to the detector. A new Monte Carlo code has been developed ad hoc for the counting of the QED events. Realistic numbers of the secondary gamma yield, obtained by using the parameters of existing or approved Compton devices, a discussion of the feasibility of the experiment and of the nature of the background are presented.
Elastic scattering of positrons on mercury: A negative-energy Dirac-Fock treatment
Sienkiewicz, J.E.; Baylis, W.E. )
1991-02-01
In a new extension of the Dirac-Fock method, calculations have been performed on the 80 electrons of mercury (in 22 {ital nlj} orbitals) plus one continuum electron of negative energy less than {minus}{ital mc}{sup 2}. The asymptotic form of the numerical wave function of the negative-energy electron determines the phase shifts for the elastic scattering of positrons on Hg. The self-consistent-field calculations include the usual exchange interaction between electrons. The exchange between the bound Hg electrons and the negative-energy continuum electron represents the positron-electron annihilation-creation process. Such effects are usually computed in quantum electrodynamics to some order of approximation in a perturbation expansion. We believe ours is the first Dirac-Fock calculation of this effect, but we find its influence on the elastic positron scattering to be negligible.
NASA Astrophysics Data System (ADS)
Oh, Ju-Won; Alkhalifah, Tariq
2016-07-01
Multi-parameter full waveform inversion (FWI) applied to an elastic orthorhombic model description of the subsurface requires in theory a nine-parameter representation of each pixel of the model. Even with optimal acquisition on the Earth surface that includes large offsets, full azimuth, and multi component sensors, the potential for tradeoff between the elastic orthorhombic parameters are large. The first step to understanding such trade-off is analysing the scattering potential of each parameter, and specifically, its scattering radiation patterns. We investigate such radiation patterns for diffraction and for scattering from a horizontal reflector considering a background isotropic model. The radiation patterns show considerable potential for trade-off between the parameters and the potentially limited resolution in their recovery. The radiation patterns of C11, C22 and C33 are well separated so that we expect to recover these parameters with limited trade-offs. However, the resolution of their recovery represented by recovered range of model wavenumbers varies between these parameters. We can only invert for the short wavelength components (reflection) of C33 while we can mainly invert for the long wavelength components (transmission) of the elastic coefficients C11 and C22 if we have large enough offsets. The elastic coefficients C13, C23 and C12 suffer from strong trade-offs with C55, C44 and C66, respectively. The trade-offs between C13 and C55, as well as C23 and C44, can be partially mitigated if we acquire P-SV and SV-SV waves. However, to reduce the trade-offs between C12 and C66, we require credible SH-SH waves. The analytical radiation patterns of the elastic constants are supported by numerical gradients of these parameters.
NASA Astrophysics Data System (ADS)
Oh, Ju-Won; Alkhalifah, Tariq
2016-09-01
Multiparameter full waveform inversion (FWI) applied to an elastic orthorhombic model description of the subsurface requires in theory a nine-parameter representation of each pixel of the model. Even with optimal acquisition on the Earth surface that includes large offsets, full azimuth, and multicomponent sensors, the potential for trade-off between the elastic orthorhombic parameters are large. The first step to understanding such trade-off is analysing the scattering potential of each parameter, and specifically, its scattering radiation patterns. We investigate such radiation patterns for diffraction and for scattering from a horizontal reflector considering a background isotropic model. The radiation patterns show considerable potential for trade-off between the parameters and the potentially limited resolution in their recovery. The radiation patterns of C11, C22, and C33 are well separated so that we expect to recover these parameters with limited trade-offs. However, the resolution of their recovery represented by recovered range of model wavenumbers varies between these parameters. We can only invert for the short wavelength components (reflection) of C33 while we can mainly invert for the long wavelength components (transmission) of the elastic coefficients C11 and C22 if we have large enough offsets. The elastic coefficients C13, C23, and C12 suffer from strong trade-offs with C55, C44, and C66, respectively. The trade-offs between C13 and C55, as well as C23 and C44, can be partially mitigated if we acquire P-SV and SV-SV waves. However, to reduce the trade-offs between C12 and C66, we require credible SH-SH waves. The analytical radiation patterns of the elastic constants are supported by numerical gradients of these parameters.
Mean square displacement evaluation by elastic neutron scattering self-distribution function.
Magazù, Salvatore; Maisano, Giacomo; Migliardo, Federica; Benedetto, Antonio
2008-06-01
In the present work an operational recipe for the mean square displacement (MSD) determination, highlighting the connection between elastic incoherent neutron scattering (EINS) intensity profiles and the associated self-distribution function, is presented. The determination of the thermal behavior of the total MSD and of its partial contributions is tested on EINS data collected by the backscattering spectrometer IN13 (ILL, Grenoble) on a model system such as PolyEthylene Glycol with a mean molecular weight of 400 Dalton (PEG 400).
Elastic scattering of 9Be+51V near the Coulomb barrier
NASA Astrophysics Data System (ADS)
Morales-Rivera, J. C.; Martinez-Quiroz, E.; Belyaeva, T. L.; Aguilera, E. F.; Lizcano, D.; Amador-Valenzuela, P.
2016-05-01
Elastic scattering angular distributions for the 9Be+51V system were measured at three near Coulomb barrier energies, Elab = 16.35, 17.44 and 18.53 MeV. The data were analyzed by using a Semimicroscopic Optical Model. This combines a microscopic calculation of the mean-field double folding potential and a phenomenological construction of the dynamical polarization potential. The calculations reproduced the data very well and the total reaction cross sections were also calculated.
Tatarskiy, D. A. Udalov, O. G.; Fraerman, A. A.
2012-10-15
It is shown that the elastic scattering of unpolarized neutrons by systems with the noncoplanar spatial magnetic induction distribution in nonreciprocal. Two systems with the noncoplanar distribution of the magnetic field are proposed and calculated, i.e., a nanoparticle with vortex magnetization and a system of three magnetic mirrors. It is shown that, under certain conditions, the nonreciprocity is rather large and can be observed experimentally.
Limit on flavor-changing neutral currents from a measurement of neutrino-electron elastic scattering
Krakauer, D.A.; Talaga, R.L. University of Maryland, College Park, Maryland 20742 ); Allen, R.C.; Chen, H.H.; Hausammann, R.; Lee, W.P.; Lu, X.; Mahler, H.J.; Wang, K.C. ); Bowles, T.J.; Burman, R.L.; Carlini, R.D.; Cochran, D.R.F.; Doe, P.J.; Frank, J.S.; Potter, M.E.; Sandberg, V.D. ); Piasetzky, E. )
1992-02-01
From a measurement of the absolute cross section in {nu}{sub {ital e}e}{sup {minus}} elastic scattering we have set a limit on flavor-changing neutral currents in the neutrino sector. We find that an off-diagonal, flavor-changing coupling is limited to 1{minus}{ital f}{sub {ital e}{ital e}}{lt}0.35 (90% C.L.).
Direct experimental reconstruction of the pp elastic scattering matrix at 579 MeV
Aprile, E.; Eisenegger, C.; Hausammann, R.; Heer, E.; Hess, R.; Lechanoine-Leluc, C.; Leo, W.R.; Morenzoni, S.; Onel, Y.; Rapin, D.; Mango, S.
1981-04-20
We have made, for the first time, a direct reconstruction of the pp elastic scattering matrix at 579 MeV from a series of experiments performed with a polarized beam line. Fifteen observables consisting of the polarization, two-spin correlation and transfer parameters, and three-spin parameters were measured at seven angles between 66/sup 0/ and 90/sup 0/ center of mass. The experimental results and reconstructed amplitudes are presented and compared to a phase-shift analysis.
NASA Astrophysics Data System (ADS)
He, J. J.; Kubono, S.; Teranishi, T.; Hu, J.; Notani, M.; Baba, H.; Nishimura, S.; Moon, J. Y.; Nishimura, M.; Iwasaki, H.; Yanagisawa, Y.; Hokoiwa, N.; Kibe, M.; Lee, J. H.; Kato, S.; Gono, Y.; Lee, C. S.
2009-07-01
The excited states in Mg22 have been investigated by the resonant elastic scattering of Na21+p. A 4.0 MeV/nucleon Na21 beam was separated by the Center for Nuclear Study (CNS) radioactive ion beam separator (CRIB) and then used to bombard a thick (CH2)n target. The energy spectra of recoiled protons were measured at scattering angles of θc.m.≈172∘,146∘, and 134∘, respectively. A wide energy-range of excitation function in Mg22 (up to Ex~8.9 MeV) was obtained simultaneously with a thick-target method, and a state at 7.06 MeV was newly observed. The resonant parameters were deduced from an R-matrix analysis of the center-of-mass (c.m.) differential cross-section data with a SAMMY-M6-BETA code. The astrophysical resonant reaction rate for the Ne18(α,p)Na21 reaction was recalculated based on the present parameters. Generally speaking, the present rates are much smaller than the previous ones.
Impact of Various Beam Parameters on Lateral Scattering in Proton and Carbon-ion Therapy
Ebrahimi Loushab, M.; Mowlavi, A.A.; Hadizadeh, M.H.; Izadi, R.; Jia, S.B.
2015-01-01
Background In radiation therapy with ion beams, lateral distributions of absorbed dose in the tissue are important. Heavy ion therapy, such as carbon-ion therapy, is a novel technique of high-precision external radiotherapy which has advantages over proton therapy in terms of dose locality and biological effectiveness. Methods In this study, we used Monte Carlo method-based Geant4 toolkit to simulate and calculate the effects of energy, shape and type of ion beams incident upon water on multiple scattering processes. Nuclear reactions have been taken into account in our calculation. A verification of this approach by comparing experimental data and Monte Carlo methods will be presented in an upcoming paper. Results Increasing particle energies, the width of the Bragg curve becomes larger but with increasing mass of particles, the width of the Bragg curve decreases. This is one of the advantages of carbon-ion therapy to treat with proton. The transverse scattering of dose distribution is increased with energy at the end of heavy ion beam range. It can also be seen that the amount of the dose scattering for carbon-ion beam is less than that of proton beam, up to about 160mm depth in water. Conclusion The distortion of Bragg peak profiles, due to lateral scattering of carbon-ion, is less than proton. Although carbon-ions are primarily scattered less than protons, the corresponding dose distributions, especially the lateral dose, are not much less. PMID:26688795
Description of elastic polarized-deuteron scattering in the optical model with Skyrme forces
NASA Astrophysics Data System (ADS)
Pilipenko, V. V.; Kuprikov, V. I.
2015-07-01
Microscopic deuteron-nucleus optical potential was constructed on the basis of the nucleon-nucleus optical potentials recently obtained by the authors from approximate calculations of the mass operator of the single-particle Green function using the Skyrme forces, which in general involve additional density- and momentum-dependent terms. Both the nucleon- and deuteron-nucleus elastic scattering processes are described in a self-consistent approach using the effective nucleon-nucleon forces, which simultaneously provide a satisfactory description of nuclear structure. The calculations performed using the Watanabe-type approximation have made it possible to obtain reasonable results for describing differential cross sections and polarization observables for the elastic deuteron scattering in a wide range of target-nucleus mass numbers at different incident deuteron energies, when using several Skyrme-force variants both from literature and proposed by the authors. Contributions to elastic deuteron-nucleus scattering cross sections coming from the effects of deuteron virtual breakup have been estimated in the continuum-discretized coupled channels approach.
Elastic scattering of 17O+208Pb at energies near the Coulomb barrier
NASA Astrophysics Data System (ADS)
Torresi, D.; Strano, E.; Mazzocco, M.; Boiano, A.; Boiano, C.; Di Meo, P.; La Commara, M.; Manea, C.; Nicoletto, M.; Grebosz, J.; Guglielmetti, A.; Molini, P.; Parascandolo, C.; Pierroutsakou, D.; Signorini, C.; Soramel, F.; Toniolo, N.; Filipescu, D.; Gheorghe, A.; Glodariu, T.; Jeong, S.; Kim, Y. H.; Lay, J. A.; Miyatake, H.; Pakou, A.; Sgouros, O.; Soukeras, V.; Stroe, L.; Vitturi, A.; Watanabe, Y.; Zerva, K.
2016-05-01
Within the frame of the commissioning of a new experimental apparatus EXPADES we undertook the measurement of the elastic scattering angular distribution for the system 17O+208Pb at energy around the Coulomb barrier. The reaction dynamics induced by loosely bound Radioactive Ion Beams is currently being extensively studied [4]. In particular the study of the elastic scattering process allows to obtain direct information on the total reaction cross section of the exotic nuclei. In order to understand the effect of the low binding energy on the reaction mechanism it is important to compare radioactive weakly bound nuclei with stable strongly-bound nuclei. In this framework the study of the 17O+208Pb elastic scattering can be considered to be complementary to a previous measurement of the total reaction cross section for the system 17F+208Pb at energies of 86, 90.4 MeV [5, 6]. The data will be compared with those obtained for the neighboring systems 16,18O+208Pb and others available in literature.
Diffractive limit approach to elastic scattering and inelastic diffraction of high-energy hadrons
NASA Astrophysics Data System (ADS)
Małecki, Andrzej
1996-09-01
An approach to inelastic diffraction based on the concept of equivalence of diffractive states is developed. In the classical description of Good and Walker, the inelastic diffraction originates from the diversity of elastic scattering amplitudes in the initial and final state Δt. We consider a multichannel correction, accounting for intermediate transitions inside the equivalence class. This correction can be factorized yielding the diffraction amplitude in the form NΔt, to be taken in the ``diffractive limit'' N-->∞, Δt-->0 such that NΔt is finite. We analyze elastic scattering and the inclusive inelastic diffraction cross sections for p-p and p-p>¯ collisions, in the range of c.m. energy √s=20-1800 GeV. We claim that the angular distribution of the inclusive inelastic diffraction at small momentum transfers is determined by elastic scattering in the transition region between the forward peak and the minimum. This is successfully verified in experiment. The detailed comparison with the Good-Walker description, with emphasis on the advantages of our approach, is presented.
Elastic scattering of vortex electrons provides direct access to the Coulomb phase
NASA Astrophysics Data System (ADS)
Ivanov, I. P.; Seipt, D.; Surzhykov, A.; Fritzsche, S.
2016-10-01
Vortex electron beams are freely propagating electron waves carrying adjustable orbital angular momentum with respect to the propagation direction. Such beams were experimentally realized just a few years ago and are now used to probe various electromagnetic processes. So far, these experiments used the single vortex electron beams, either propagating in external fields or impacting a target. Here, we investigate the elastic scattering of two such aligned vortex electron beams and demonstrate that this process allows one to experimentally measure features which are impossible to detect in the usual plane-wave scattering. The scattering amplitude of this process is well approximated by two plane-wave scattering amplitudes with different momentum transfers, which interfere and give direct experimental access to the Coulomb phase. This phase (shift) affects the scattering of all charged particles and has thus received significant theoretical attention but was never probed experimentally. We show that a properly defined azimuthal asymmetry, which has no counterpart in plane-wave scattering, allows one to directly measure the Coulomb phase as function of the scattering angle.
NASA Astrophysics Data System (ADS)
Cantero, E. D.; Lantschner, G. H.; Eckardt, J. C.; Lovey, F. C.; Arista, N. R.
2010-04-01
Measurements of angular distributions and of the angular dependence of the energy loss of 4-, 6-, and 9-keV protons transmitted through thin Cu and Ag polycrystalline foils are presented. By means of standard multiple-scattering model calculations it is found that a V(r)∝r-2.8 potential leads to significantly better fits of the angular distributions than the standard Thomas Fermi, Lenz-Jensen, or Ziegler-Biersack-Littmark potentials. A theoretical model for the angular dependence of the energy loss based on considering geometric effects on a frictional inelastic energy loss plus an angular-dependent elastic contribution and the effects of foil roughness reproduces the experimental data. This agrees with previous results in Au and Al, therefore extending the applicability of the model to other metallic elements.
NASA Astrophysics Data System (ADS)
Lindsley, E. H.; Farkas, D. L.
2008-02-01
We have designed and built an imaging elastic scattering spectroscopy endoscopic instrument for the purpose of detecting cancer in vivo. As part of our testing and validation of the system, known targets representing potential disease states of interest were constructed using polystyrene beads of known average diameter and TiO II crystals embedded in a two-layer agarose gel. Final construction geometry was verified using a dissection microscope. The phantoms were then imaged using the endoscopic probe at a known incident angle, and the results compared to model predictions. The mathematical model that was used combines classic ray-tracing optics with Mie scattering to predict the images that would be observed by the probe at a given physical distance from a Mie-regime scattering media. This model was used generate the expected observed response for a broad range of parameter values, and these results were then used as a library to fit the observed data from the phantoms. Compared against the theoretical library, the best matching signal correlated well with known phantom material dimensions. These results lead us to believe that imaging elastic scattering can be useful in detection/diagnosis, but further refinement of the device will be necessary to detect the weak signals in a real clinical setting.
Antihydrogen-hydrogen elastic scattering at thermal energies using an atomic-orbital technique
Sinha, Prabal K.; Chaudhuri, Puspitapallab; Ghosh, A.S.
2003-05-01
In view of the recent interest in the trapping of antihydrogen atom H(bar sign), at very low temperatures, H-bar-H scattering has been investigated at low incident energies using a close-coupling model with the basis set H-bar(1s,2s,2p-bar)+H(1s,2s,2p-bar). The predicted s-wave elastic phase shifts, scattering length, and effective range are in a good agreement with the other recent predictions of Jonsell et al. and of Armour and Chamberlain. The results indicate that the atomic orbital expansion model is suitable to study the H-bar-H scattering at ultracold temperatures.
Elastic electron scattering from water vapor and ice at high momentum transfer.
Vos, M; Weigold, E; Moreh, R
2013-01-28
We compare the area, peak separation, and width of the H and O elastic peak for light and heavy water, as observed in spectra of keV electrons scattered over large angles. Peak separation is well reproduced by the theory, but the O:H area ratio is somewhat larger than expected and is equal to the O:D area ratio. Thus no anomalous scattering from H was observed. Only minor differences are observed for scattering from a gaseous or a solid target. The extracted mean kinetic energy of H and D agreed within 5% with the calculated ones for ice. For the more difficult vapor measurements agreement was on a 12% level. A preliminary attempt to extract the O kinetic energy in ice agreed within 10% with the calculated values.
Measurements of anomalous elastic scattering of 59.54-keV photons
Baraldi, C.; Casnati, E.; Tartari, A.; Andreis, M.; Singh, B.
1996-12-01
Coherent scattering cross sections of 59.54-keV photons on target foils of {sup 64}Gd, {sup 66}Dy, {sup 68}Er, {sup 70}Yb, {sup 72}Hf, and {sup 73}Ta at 60{degree}, 90{degree}, and 120{degree} have been measured to provide information on the region of {ital K} anomalous elastic scattering. The results are compared with the values calculated by the second perturbative order {ital S} matrix and by two procedures based on the form-factor approximation corrected by the anomalous scattering factors. Agreement of the {ital S} matrix values is very satisfactory, on the whole, and that of the values given by the form-factor approximations is fairly good. {copyright} {ital 1996 The American Physical Society.}
Kuprikov, V. I.; Pilipenko, V. V.
2013-01-15
A microscopic optical nucleon-nucleus potential constructed on the basis of calculating the mass operator for the single-particle Green's function with Skyrme nucleon-nucleon forces was used to study the effect of the tensor part of Skyrme forces on describing differential cross sections for elastic nucleon-nucleus scattering and the structure of nuclei within a self-consistent approach. It was shown that an increase in the tensor terms of nucleon-nucleon forces impaired the description of nucleon-nucleus scattering within the model being considered. The parameters of Skyrme forces were optimized on the basis of an analysis of cross sections for neutron-nucleus scattering, the properties of nuclear matter and the structure of nuclei being tested in doing this. This optimization led to nucleon-nucleon force versions where the tensor part was small or zero and which described satisfactorily the structure of nuclei and cross sections for elastic neutron and proton scattering on nuclei over a broad range of target mass numbers.
Antiplane wave scattering from a cylindrical cavity in pre-stressed nonlinear elastic media
Shearer, Tom; Parnell, William J.; Abrahams, I. David
2015-01-01
The effect of a longitudinal stretch and a pressure-induced inhomogeneous radial deformation on the scattering of antiplane elastic waves from a cylindrical cavity is determined. Three popular nonlinear strain energy functions are considered: the neo-Hookean, the Mooney–Rivlin and a two-term Arruda–Boyce model. A new method is developed to analyse and solve the governing wave equations. It exploits their properties to determine an asymptotic solution in the far-field, which is then used to derive a boundary condition to numerically evaluate the equations local to the cavity. This method could be applied to any linear ordinary differential equation whose inhomogeneous coefficients tend to a constant as its independent variable tends to infinity. The effect of the pre-stress is evaluated by considering the scattering cross section. A longitudinal stretch is found to decrease the scattered power emanating from the cavity, whereas a compression increases it. The effect of the pressure difference depends on the strain energy function employed. For a Mooney–Rivlin material, a cavity inflation increases the scattered power and a deflation decreases it; for a neo-Hookean material, the scattering cross section is unaffected by the radial deformation; and for a two-term Arruda–Boyce material, both inflation and deflation are found to decrease the scattered power. PMID:26543398
Jet production in muon-proton and muon-nuclei scattering at Fermilab-E665
Salgado, C.W.; E665 Collaboration
1993-08-01
Measurements of multi-jet production rates from Muon-Proton Muon- Nuclei scattering at Fermilab-E665 are presented. Jet rates are defined by the JADE clustering algorithm. Rates in Muon-Proton deep-inelastic scattering are compared to perturbative Quantum Chromodynamics (PQCD) and Monte Carlo model predictions. We observe hadronic (2+1)-jet rates which are a factor of two higher than PQCD predictions at the partonic level. Preliminary results from jet production on heavy targets, in the shadowing region, show a suppression of the jet rates as compared to deuterium. The two- forward jet sample present higher suppression as compared to the one-forward jet sample.
Imaging the proton via hard exclusive production in diffractive pp scattering
Charles Hyde; Leonid Frankfurt; Mark Strikman; Christian Weiss
2007-05-21
We discuss the prospects for probing Generalized Parton Distributions (GPDs) via exclusive production of a high-mass system (H = heavy quarkonium, di-photon, di-jet, Higgs boson) in diffractive pp scattering, pp -> p + H + p. In such processes the interplay of hard and soft interactions gives rise to a diffraction pattern in the final-state proton transverse momenta, which is sensitive to the transverse spatial distribution of partons in the colliding protons. We comment on the plans for diffractive pp measurements at RHIC and LHC. Such studies could complement future measurements of GPDs in hard exclusive ep scattering (JLab, COMPASS, EIC).
NASA Astrophysics Data System (ADS)
Flammini, D.; Pietropaolo, A.; Senesi, R.; Andreani, C.; McBride, F.; Hodgson, A.; Adams, M. A.; Lin, L.; Car, R.
2012-01-01
The spherical momentum distribution of the protons in ice is extracted from a high resolution deep inelastic neutron scattering experiment. Following a recent path integral Car-Parrinello molecular dynamics study, data were successfully interpreted in terms of an anisotropic Gaussian model, with a statistical accuracy comparable to that of the model independent scheme used previously, but providing more detailed information on the three dimensional potential energy surface experienced by the proton. A recently proposed theoretical concept is also employed to directly calculate the mean force from the experimental neutron Compton profile, and to evaluate the accuracy required to unambiguously resolve and extract the effective proton potential from the experimental data.
Flammini, D; Pietropaolo, A; Senesi, R; Andreani, C; McBride, F; Hodgson, A; Adams, M A; Lin, L; Car, R
2012-01-14
The spherical momentum distribution of the protons in ice is extracted from a high resolution deep inelastic neutron scattering experiment. Following a recent path integral Car-Parrinello molecular dynamics study, data were successfully interpreted in terms of an anisotropic Gaussian model, with a statistical accuracy comparable to that of the model independent scheme used previously, but providing more detailed information on the three dimensional potential energy surface experienced by the proton. A recently proposed theoretical concept is also employed to directly calculate the mean force from the experimental neutron Compton profile, and to evaluate the accuracy required to unambiguously resolve and extract the effective proton potential from the experimental data. PMID:22260600
NASA Astrophysics Data System (ADS)
Wang, Zaijun; Ren, Zhongzhou; Dong, Tiekuang; Xu, Chang
2014-08-01
The ground-state spins and parities of the odd-A phosphorus isotopes 25-47P are studied with the relativistic mean-field (RMF) model and relativistic elastic magnetic electron-scattering theory (REMES). Results of the RMF model with the NL-SH, TM2, and NL3 parameters show that the 2s1/2 and 1d3/2 proton level inversion may occur for the neutron-rich isotopes 37-47P, and, consequently, the possible spin-parity values of 37-47P may be 3/2+, which, except for P47, differs from those given by the NUBASE2012 nuclear data table by Audi et al. Calculations of the elastic magnetic electron scattering of 37-47P with the single valence proton in the 2s1/2 and 1d3/2 state show that the form factors have significant differences. The results imply that elastic magnetic electron scattering can be a possible way to study the 2s1/2 and 1d3/2 level inversion and the spin-parity values of 37-47P. The results can also provide new tests as to what extent the RMF model, along with its various parameter sets, is valid for describing the nuclear structures. In addition, the contributions of the upper and lower components of the Dirac four-spinors to the form factors and the isotopic shifts of the magnetic form factors are discussed.
NASA Astrophysics Data System (ADS)
Csörgő, T.
2016-07-01
Recently published and preliminary results of the TOTEM experiment are presented, emphasizing a recent discovery of a non-exponential behaviour of the differential crosssection of elastic proton-proton scattering, that TOTEM measured with an unprecedented precision at the centre-of-mass energy √s = 8 TeV based on a high-statistics data sample obtained with the β* = 90 m optics of CERN LHC. Both the statistical and systematic uncertainties remained below 1%, except for the t-independent contribution from the overall normalisation. This measurement allowed TOTEM to exclude a purely exponential differential cross-section in the range of four-momentum transfer squared 0.027 < |t| < 0.2 GeV2 with a significance greater than 7σ. In this context we also highlight the innovative TOTEM recalibration of LHC optics, that used elastic scattering data measured by the world's largest and most complex Roman Pot detector system, and discuss recent preliminary TOTEM data on the Coulomb-Nuclear interference region with its physics implications.
NASA Astrophysics Data System (ADS)
Yoder, Timothy J.
2000-05-01
The solutions for acoustic scattering from objects in separable geometries along with the associated fluid- structure interactions are well established. Closed-form solutions to these problems have either interpretations such as resonance scattering theory, or some limiting situations that provide insight into the physical processes that occur. In contrast, most acoustical scattering problems do not have closed-form solutions. Numerical solutions, like finite and boundary element methods, allow researchers to obtain solutions from scattering problems with more complicated geometries; unfortunately, these methods of solution are limited in that they lack the kind of interpretation that provides insight into the physical processes that occur. It is only through the systematic analysis of the large volume of data produced by numerical solutions that this insight is gained. One way to gain this insight is to analyze the monostatic dependence of echoes in the time-frequency domain. However, traditional three-dimensional graphical analysis of time-frequency signals that vary as a function of a third parameter (the monostatic dependence) does not display all of the signals' information content because two marginals, of this distribution (the time and frequency representations) contain information that is lost in the visual representation of the time-frequency domain. This information is lost because the uncertainty principal prevents simultaneous display of the time and frequency information via a time-frequency transform, and because humans do not possess the innate ability to perform the transforms that extract the information. The problem of how to systematically analyze monostatic scattering data in the time-frequency domain and how to visually display all of the data's information content is overcome by introducing a time-frequency-parameter graphical analysis technique. This technique is applied to farfield acoustic scattering from finite, elastic, cylindrical
Neutron scattered dose equivalent to a fetus from proton radiotherapy of the mother.
Mesoloras, Geraldine; Sandison, George A; Stewart, Robert D; Farr, Jonathan B; Hsi, Wen C
2006-07-01
Scattered neutron dose equivalent to a representative point for a fetus is evaluated in an anthropomorphic phantom of the mother undergoing proton radiotherapy. The effect on scattered neutron dose equivalent to the fetus of changing the incident proton beam energy, aperture size, beam location, and air gap between the beam delivery snout and skin was studied for both a small field snout and a large field snout. Measurements of the fetus scattered neutron dose equivalent were made by placing a neutron bubble detector 10 cm below the umbilicus of an anthropomorphic Rando phantom enhanced by a wax bolus to simulate a second trimester pregnancy. The neutron dose equivalent in milliSieverts (mSv) per proton treatment Gray increased with incident proton energy and decreased with aperture size, distance of the fetus representative point from the field edge, and increasing air gap. Neutron dose equivalent to the fetus varied from 0.025 to 0.450 mSv per proton Gray for the small field snout and from 0.097 to 0.871 mSv per proton Gray for the large field snout. There is likely to be no excess risk to the fetus of severe mental retardation for a typical proton treatment of 80 Gray to the mother since the scattered neutron dose to the fetus of 69.7 mSv is well below the lower confidence limit for the threshold of 300 mGy observed for the occurrence of severe mental retardation in prenatally exposed Japanese atomic bomb survivors. However, based on the linear no threshold hypothesis, and this same typical treatment for the mother, the excess risk to the fetus of radiation induced cancer death in the first 10 years of life is 17.4 per 10,000 children. PMID:16898451
Neutron scattered dose equivalent to a fetus from proton radiotherapy of the mother.
Mesoloras, Geraldine; Sandison, George A; Stewart, Robert D; Farr, Jonathan B; Hsi, Wen C
2006-07-01
Scattered neutron dose equivalent to a representative point for a fetus is evaluated in an anthropomorphic phantom of the mother undergoing proton radiotherapy. The effect on scattered neutron dose equivalent to the fetus of changing the incident proton beam energy, aperture size, beam location, and air gap between the beam delivery snout and skin was studied for both a small field snout and a large field snout. Measurements of the fetus scattered neutron dose equivalent were made by placing a neutron bubble detector 10 cm below the umbilicus of an anthropomorphic Rando phantom enhanced by a wax bolus to simulate a second trimester pregnancy. The neutron dose equivalent in milliSieverts (mSv) per proton treatment Gray increased with incident proton energy and decreased with aperture size, distance of the fetus representative point from the field edge, and increasing air gap. Neutron dose equivalent to the fetus varied from 0.025 to 0.450 mSv per proton Gray for the small field snout and from 0.097 to 0.871 mSv per proton Gray for the large field snout. There is likely to be no excess risk to the fetus of severe mental retardation for a typical proton treatment of 80 Gray to the mother since the scattered neutron dose to the fetus of 69.7 mSv is well below the lower confidence limit for the threshold of 300 mGy observed for the occurrence of severe mental retardation in prenatally exposed Japanese atomic bomb survivors. However, based on the linear no threshold hypothesis, and this same typical treatment for the mother, the excess risk to the fetus of radiation induced cancer death in the first 10 years of life is 17.4 per 10,000 children.
Neutron scattered dose equivalent to a fetus from proton radiotherapy of the mother
Mesoloras, Geraldine; Sandison, George A.; Stewart, Robert D.; Farr, Jonathan B.; Hsi, Wen C.
2006-07-15
Scattered neutron dose equivalent to a representative point for a fetus is evaluated in an anthropomorphic phantom of the mother undergoing proton radiotherapy. The effect on scattered neutron dose equivalent to the fetus of changing the incident proton beam energy, aperture size, beam location, and air gap between the beam delivery snout and skin was studied for both a small field snout and a large field snout. Measurements of the fetus scattered neutron dose equivalent were made by placing a neutron bubble detector 10 cm below the umbilicus of an anthropomorphic Rando[reg] phantom enhanced by a wax bolus to simulate a second trimester pregnancy. The neutron dose equivalent in milliSieverts (mSv) per proton treatment Gray increased with incident proton energy and decreased with aperture size, distance of the fetus representative point from the field edge, and increasing air gap. Neutron dose equivalent to the fetus varied from 0.025 to 0.450 mSv per proton Gray for the small field snout and from 0.097 to 0.871 mSv per proton Gray for the large field snout. There is likely to be no excess risk to the fetus of severe mental retardation for a typical proton treatment of 80 Gray to the mother since the scattered neutron dose to the fetus of 69.7 mSv is well below the lower confidence limit for the threshold of 300 mGy observed for the occurrence of severe mental retardation in prenatally exposed Japanese atomic bomb survivors. However, based on the linear no threshold hypothesis, and this same typical treatment for the mother, the excess risk to the fetus of radiation induced cancer death in the first 10 years of life is 17.4 per 10 000 children.
Looking at hydrogen motions in confinement. The uniqueness of Quasi-Elastic Neutron Scattering
NASA Astrophysics Data System (ADS)
Fischer, J.; Tsapatsaris, N.; de Paula, E.; Bordallo, H. N.
2014-09-01
Why in a barren and hot desert, clays can contain a significant fraction of water? Why does concrete crack? How can we demonstrate that complexation of a drug does not alter its conformation in a way that affects its functionality? In this paper we present results on various studies using Quasi-Elastic Neutron Scattering aimed at clarifying these questions. To allow for a better understanding of neutron scattering, a brief introduction to the basics of its theory is presented. Following the theoretical part, experimental results dealing with the effects of confinement on the water dynamics caused by the interfaces in clays and the nano- and micro-pores of concrete are reviewed in detail. At the end, recent Quasi-Elastic Neutron Scattering investigations on the complexation of the local anesthetics Bupivacaine (BVC.HCl, C18H28N20.HCl.H2O) and Ropivacaine (RVC.HCl, C17H26N20.HCl.H2O) into the cyclic β-cyclodextrin oligosaccharide are presented. To conclude, the perspectives that the European Spallation Source brings to this subject are discussed.
Quasi-elastic neutron scattering studies of the slow dynamics of supercooled and glassy aspirin
NASA Astrophysics Data System (ADS)
Zhang, Yang; Tyagi, Madhusudan; Mamontov, Eugene; Chen, Sow-Hsin
2012-02-01
Aspirin, also known as acetylsalicylic acid (ASA), is not only a wonderful drug, but also a good glass former. Therefore, it serves as an important molecular system to study the near-arrest and arrested phenomena. In this paper, a high-resolution quasi-elastic neutron scattering (QENS) technique is used to investigate the slow dynamics of supercooled liquid and glassy aspirin from 410 down to 350 K. The measured QENS spectra can be analyzed with a stretched exponential model. We find that (i) the stretched exponent β(Q) is independent of the wavevector transfer Q in the measured Q range and (ii) the structural relaxation time τ(Q) follows a power-law dependence on Q. Consequently, the Q-independent structural relaxation time τ0 can be extracted for each temperature to characterize the slow dynamics of aspirin. The temperature dependence of τ0 can be fitted with the mode-coupling power law, the Vogel-Fulcher-Tammann equation and a universal equation for fragile glass forming liquids recently proposed by Tokuyama in the measured temperature range. The calculated dynamic response function χT(Q, t) using the experimentally determined self-intermediate scattering function of the hydrogen atoms of aspirin shows direct evidence of the enhanced dynamic fluctuations as the aspirin is increasingly supercooled, in agreement with the fixed-time mean squared displacement langx2rang and the non-Gaussian parameter α2 extracted from the elastic scattering.
Quasi-Elastic Neutron Scattering Studies of the Slow Dynamics of Supercooled and Glassy Aspirin
Zhang, Yang; Tyagi, M.; Mamontov, Eugene; Chen, Sow-hsin H
2011-01-01
Aspirin, also known as acetylsalicylic acid (ASA), is not only a wonderful drug, but also a good glass former. Therefore, it serves as an important molecular system to study the near-arrest and arrested phenomena. In this paper, a high-resolution quasi-elastic neutron scattering (QENS) technique is used to investigate the slow dynamics of supercooled liquid and glassy aspirin from 410 K down to 350 K. The measured QENS spectra can be analyzed with a stretched exponential model. We find that (i) the stretched exponent (Q) is independent of the wave vector transfer Q in the measured Q-range, and (ii) the structural relaxation time (Q) follows a power law dependence on Q. Consequently, the Q-independent structural relaxation time 0 can be extracted for each temperature to characterize the slow dynamics of aspirin. The temperature dependence of 0 can be fitted with the mode coupling power law, the Vogel-Fulcher-Tammann equation and a universal equation for fragile glass forming liquids recently proposed by M. Tokuyama in the measured temperature range. The calculated dynamic response function T(Q,t) using the experimentally determined self-intermediate scattering function of the hydrogen atoms of aspirin shows a direct evidence of the enhanced dynamic fluctuations as the aspirin is increasingly supercooled, in agreement with the fixed-time mean squared displacement x2 and non-Gaussian parameter 2 extracted from the elastic scattering.
Biophotonics of skin: method for correction of deep Raman spectra distorted by elastic scattering
NASA Astrophysics Data System (ADS)
Roig, Blandine; Koenig, Anne; Perraut, François; Piot, Olivier; Gobinet, Cyril; Manfait, Michel; Dinten, Jean-Marc
2015-03-01
Confocal Raman microspectroscopy allows in-depth molecular and conformational characterization of biological tissues non-invasively. Unfortunately, spectral distortions occur due to elastic scattering. Our objective is to correct the attenuation of in-depth Raman peaks intensity by considering this phenomenon, enabling thus quantitative diagnosis. In this purpose, we developed PDMS phantoms mimicking skin optical properties used as tools for instrument calibration and data processing method validation. An optical system based on a fibers bundle has been previously developed for in vivo skin characterization with Diffuse Reflectance Spectroscopy (DRS). Used on our phantoms, this technique allows checking their optical properties: the targeted ones were retrieved. Raman microspectroscopy was performed using a commercial confocal microscope. Depth profiles were constructed from integrated intensity of some specific PDMS Raman vibrations. Acquired on monolayer phantoms, they display a decline which is increasing with the scattering coefficient. Furthermore, when acquiring Raman spectra on multilayered phantoms, the signal attenuation through each single layer is directly dependent on its own scattering property. Therefore, determining the optical properties of any biological sample, obtained with DRS for example, is crucial to correct properly Raman depth profiles. A model, inspired from S.L. Jacques's expression for Confocal Reflectance Microscopy and modified at some points, is proposed and tested to fit the depth profiles obtained on the phantoms as function of the reduced scattering coefficient. Consequently, once the optical properties of a biological sample are known, the intensity of deep Raman spectra distorted by elastic scattering can be corrected with our reliable model, permitting thus to consider quantitative studies for purposes of characterization or diagnosis.
NASA Astrophysics Data System (ADS)
Tortet, L.; Gavarri, J. R.; Nihoul, G.; Dianoux, A. J.
1997-08-01
We report the first quasi-elastic neutron scattering analysis of proton mobility in the solid electrolyte CaHPO4·2H2O (brushite). We have studied this hydrated phosphate, in powder state, from 190 to 520 K, using an incident wavelength of 5.12 Å. The time of flight spectra are converted inS(Q,ω) structure factor and inelastic frequency distributionP(Q,ω) in the energy range 0-200 meV (0-1600 cm)-1. A quasi-elastic contribution is clearly evidenced above room temperature; it is fitted with a jump model, involving hydrogen bonds. The quasi-elastic and inelastic scattering data are compared with FTIR results. Two kinds of motions are determined: jumps of acidic protons on hydrogen bonds and vibrations of lattice water molecules associated with the motion of their hydrogen atom on hydrogen bonds (Ea≈0.145 eV). Above 450 K the dehydration of the compound is accompanied by the appearance of a long-range diffusive motion and by the disappearance of some low-frequency inelastic bands.
Finite Element Prediction of Acoustic Scattering and Radiation from Submerged Elastic Structures
NASA Technical Reports Server (NTRS)
Everstine, G. C.; Henderson, F. M.; Lipman, R. R.
1984-01-01
A finite element formulation is derived for the scattering and radiation of acoustic waves from submerged elastic structures. The formulation uses as fundamental unknowns the displacement in the structure and a velocity potential in the field. Symmetric coefficient matrices result. The outer boundary of the fluid region is terminated with an approximate local wave-absorbing boundary condition which assumes that outgoing waves are locally planar. The finite element model is capable of predicting only the near-field acoustic pressures. Far-field sound pressure levels may be determined by integrating the surface pressures and velocities over the wet boundary of the structure using the Helmholtz integral. Comparison of finite element results with analytic results show excellent agreement. The coupled fluid-structure problem may be solved with general purpose finite element codes by using an analogy between the equations of elasticity and the wave equation of linear acoustics.
s-wave elastic scattering of antihydrogen off atomic alkali-metal targets
Sinha, Prabal K.; Ghosh, A. S.
2006-03-15
We have investigated the s-wave elastic scattering of antihydrogen atoms off atomic alkali-metal targets (Li, Na, K, and Rb) at thermal energies (10{sup -16}-10{sup -4} a.u.) using an atomic orbital expansion technique. The elastic cross sections of these systems at thermal energies are found to be very high compared to H-H and H-He systems. The theoretical models employed in this study are so chosen to consider long-range forces dynamically in the calculation. The mechanism of cooling suggests that Li may be considered to be a good candidate as a buffer gas for enhanced cooling of antihydrogen atoms to ultracold temperature.
Low-energy photodetachment of Ga- and elastic electron scattering from neutral Ga
NASA Astrophysics Data System (ADS)
Wang, Kedong; Zatsarinny, Oleg; Bartschat, Klaus
2016-08-01
We present a comprehensive study of the photodetachment of the negative gallium ion and elastic electron scattering from neutral Ga for photon and electron energies ranging from threshold to 12 eV. The calculations are carried out with the B -spline R -matrix method. A multiconfiguration Hartree-Fock method with nonorthogonal term-dependent orbitals is employed to generate accurate initial- and final-state wave functions. The close-coupling expansions include the 4 s 24 p n l (k l ) bound and continuum states of Ga and the 4 s -excited autoionizing states 4 s 4 p2 . The calculated photodetachment and elastic cross sections exhibit prominent resonance features. In order to clarify the origin of these resonances, the contributions of the major ionization channels to the partial cross sections are analyzed in detail.
NASA Astrophysics Data System (ADS)
Hall, Richard; Miyachi, Kouichi; Newton, David; Takezoe, Hideo; Fukuda, Atsuo
1992-02-01
The effects of the finite scattering volume on the values of elastic constant ratios determined have been studied by computer simulation. The errors in the simulated values of K1/K2 and K3/K2 are dependent on the position of the starting angle of the scan. The error is greatest for thinner cells (≈7 μm) and in the angular regions where the geometrical factor Gm introduced by de Gennes, or a component of the scattering vector q becomes zero, i.e. for external scattering angles approximately less than 10° and those between approximately 20° and 60°, depending on the scattering geometry used. The approximation introduced by van der Meulen and Zijlstra in defining the orthogonal base system (\\hat{\\mbi{e}}1, \\hat{\\mbi{e}}2, \\hat{\\mbi{e}}3) has also been discussed; it is inappropriate in thin cells to use the scattering vector q instead of the wave vector \\mbi{k}l of the director fluctuations when determining K1/K2.
NASA Astrophysics Data System (ADS)
Gusev, V. V.; Guseva, N. P.; Tatarintsev, S. N.
1995-01-01
In this paper the principle possibility for determining the incorporation efficiency of plague capsular antigen (PCA) into liposomes on the basis of elastic light scattering is shown. To find the most informative index, which characterizes the process of PCA sorption into liposomes, the angular light scattering dependencies for the liposome suspensions containing various PCA concentrations were measured by means of laser polarization nephelometer. Its construction and measurement technique are described in detail. For all preparations to be investigated, the incorporation efficiency was determined using traditional biochemical method and correlation between the scattering matrix element values and the incorporation efficiency was made. The most informative index, characterizing the process of PCA incorporation into the liposomes, appeared to be the light scattering integral intensity (LSII) at an angle of 90 degree(s). It was found that the PCA incorporation into liposomes results in the LSII increasing by a factor of 2 - 5 times in the incorporation efficiency range from 5% to 45%. The electron microscopy data and angular dependencies for the light scattering matrix elements have shown that LSII increase is due to the refraction index variation of the liposome membrane. The obtained LSII dependence on the incorporation efficiency enables us to determine the PCA incorporation efficiency into the liposomes by measuring the LSII.
NASA Astrophysics Data System (ADS)
Sacchi, M.; Jaouen, N.; Popescu, H.; Gaudemer, R.; Tonnerre, J. M.; Chiuzbaian, S. G.; Hague, C. F.; Delmotte, A.; Dubuisson, J. M.; Cauchon, G.; Lagarde, B.; Polack, F.
2013-03-01
SEXTANTS is a new SOLEIL beamline dedicated to soft X-ray scattering techniques. The beamline, covering the 50-1700 eV energy range, features two Apple-II undulators for polarization control and a fixed-deviation monochromator. Two branch-lines host three end-stations for elastic, inelastic and coherent scattering experiments.
NASA Astrophysics Data System (ADS)
Nuruzzaman, FNU
The Q-weak experiment in Hall-C at the Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton through the precision measurement of the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer. There is also a parity conserving Beam Normal Single Spin Asymmetry or transverse asymmetry (Bn) on H2 with a sin(phi)-like dependence due to two-photon exchange. If the size of elastic Bn is a few ppm, then a few percent residual transverse polarization in the beam, combined with small broken azimuthal symmetries in the detector, would require a few ppb correction to the Q-weak data. As part of a program of Bn background studies, we made the first measurement of Bn in the N-to-Delta(1232) transition using the Q-weak apparatus. The final transverse asymmetry, corrected for backgrounds and beam polarization, was found to be Bn = 42.82 +- 2.45 (stat) +- 16.07 (sys) ppm at beam energy Ebeam = 1.155 GeV, scattering angle theta = 8.3 degrees, and missing mass W = 1.2 GeV. Bn from electron-nucleon scattering is a unique tool to study the gamma*DeltaDelta form factors, and this measurement will help to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process. To help correct false asymmetries from beam noise, a beam modulation system was implemented to induce small position, angle, and energy changes at the target to characterize detector response to the beam jitter. Two air-core dipoles separated by ˜10 m were pulsed at a time to produce position and angle changes at the target, for virtually any tune of the beamline. The beam energy was modulated using an SRF cavity. The hardware and associated control instrumentation will be described in this dissertation. Preliminary detector sensitivities were extracted which helped to reduce the width of the measured asymmetry. The beam modulation system has
., Nuruzzaman
2014-12-01
The Q-weak experiment in Hall-C at the Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton through the precision measurement of the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer. There is also a parity conserving Beam Normal Single Spin Asymmetry or transverse asymmetry (B_n) on H_2 with a sin(phi)-like dependence due to two-photon exchange. If the size of elastic B_n is a few ppm, then a few percent residual transverse polarization in the beam, combined with small broken azimuthal symmetries in the detector, would require a few ppb correction to the Q-weak data. As part of a program of B_n background studies, we made the first measurement of B_n in the N-to-Delta(1232) transition using the Q-weak apparatus. The final transverse asymmetry, corrected for backgrounds and beam polarization, was found to be B_n = 42.82 ± 2.45 (stat) ± 16.07 (sys) ppm at beam energy E_beam = 1.155 GeV, scattering angle theta = 8.3 deg, and missing mass W = 1.2 GeV. B_n from electron-nucleon scattering is a unique tool to study the gamma^* Delta Delta form factors, and this measurement will help to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process. To help correct false asymmetries from beam noise, a beam modulation system was implemented to induce small position, angle, and energy changes at the target to characterize detector response to the beam jitter. Two air-core dipoles separated by ~10 m were pulsed at a time to produce position and angle changes at the target, for virtually any tune of the beamline. The beam energy was modulated using an SRF cavity. The hardware and associated control instrumentation will be described in this dissertation. Preliminary detector sensitivities were extracted which helped to reduce the width of the measured asymmetry. The beam modulation system
Computation of doses for large-angle Coulomb scattering of proton pencil beams.
Ciangaru, George; Sahoo, Narayan; Zhu, X Ronald; Sawakuchi, Gabriel O; Gillin, Michael T
2009-12-21
In this work we present a study of the impact of considering higher order terms in Molière's multiple Coulomb scattering (MCS) theory for the purpose of calculating scanning proton pencil beam lateral dose profiles in water. The proton beam profile in air, just before entering the target medium, was modeled with a sum of Gaussians fitted with measured data. The subsequent proton scattering in water was described using the three-term Molière distribution, which covers both small- and large-angle scatterings. We compared measured and computed lateral dose profiles at the 2 cm and at the near-Bragg peak depths for proton pencil beams with energies of 72.5 MeV, 121.2 MeV, 163.9 MeV and 221.8 MeV. At shallow depths, the Coulomb interaction model provided a good description of the profiles for all energies, except for 221.8 MeV. At the near-Bragg peak depths, the Coulomb interaction model provided a good description of the profiles only for the 72.5 MeV. The observed discrepancies may be attributed to the additional contributions from nuclear interactions, which may be quantified only after an accurate description of the MCS. The analysis presented in this work did not require user-adjustable parameters and may be carried out in a similar way for any other media, depths and proton energies.
Taddei, Phillip J; Fontenot, Jonas D; Zheng, Yuanshui; Mirkovic, Dragan; Lee, Andrew K; Titt, Uwe; Newhauser, Wayne D
2014-01-01
Proton beam radiotherapy exposes healthy tissue to stray radiation emanating from the treatment unit and secondary radiation produced within the patient. These exposures provide no known benefit and may increase a patient's risk of developing a radiogenic second cancer. The aim of this study was to explore strategies to reduce stray radiation dose to a patient receiving a 76 Gy proton beam treatment for cancer of the prostate. The whole-body effective dose from stray radiation, E, was estimated using detailed Monte Carlo simulations of a passively scattered proton treatment unit and an anthropomorphic phantom. The predicted value of E was 567 mSv, of which 320 mSv was attributed to leakage from the treatment unit; the remainder arose from scattered radiation that originated within the patient. Modest modifications of the treatment unit reduced E by 212 mSv. Surprisingly, E from a modified passive-scattering device was only slightly higher (109 mSv) than from a nozzle with no leakage, e.g., that which may be approached with a spot-scanning technique. These results add to the body of evidence supporting the suitability of passively scattered proton beams for the treatment of prostate cancer, confirm that the effective dose from stray radiation was not excessive, and, importantly, show that it can be substantially reduced by modest enhancements to the treatment unit. PMID:18369278
Extracting hadron-neutron scattering amplitudes from hadron-proton and hadron-deuteron measurements
NASA Technical Reports Server (NTRS)
Franco, V.
1977-01-01
A method is presented for extracting hadron-neutron scattering amplitudes from hadron-proton and hadron-deuteron measurements within the framework of the Glauber approximation. This method, which involves the solution of a linear integral equation, is applied to pn collisions between 15 and 275 GeV/c. Effects arising from inelastic intermediate states are estimated.
A study of proton-deuteron scattering in configuration space
NASA Astrophysics Data System (ADS)
Suslov, Vladimir; Braun, Mikhail; Filikhin, Igor; Vlahovic, Branislav
2007-10-01
A new computational method for solving the configuration-space Faddeev equations for the breakup scattering problem [1] has been applied to consider the pd scattering below and above the deuteron threshold. To perform numerical calculations for arbitrary nuclear potential and with arbitrary number of partial waves retained we use approach proposed in [2]. The calculations of the inelasticity and phase-shift for various lab energies were performed with the charge independent AV14 potential. The results are compared with those of other authors [3, 4]. 1. V.M. Suslov and B. Vlahovic, Phys. Rev. C69, 044003 (2004). 2. S.P. Merkuriev, C. Gignoux and A. Laverne, Ann. Phys. 99, 30 (1976). 3. A.Kievsky, J.L Friar, G.L. Payne, S. Rosati, M. Viviani, Phys. Rev. C63, 064004 (2001). 4. A. Deltuva, A.C. Fonseca, A.Kievsky, S. Rosati, P.U. Sauer, and M. Viviani, Phys. Rev. C74, 064003 (2005).
Study of Quasi-Elastic Scattering in the NOnuA Detector Prototype
NASA Astrophysics Data System (ADS)
Betancourt, Minerba
NOvA is a 810 km long base-line neutrino oscillation experiment with two detectors (far 14 KTon and near detector 300 Ton) currently being installed in the NUMI off-axis neutrino beam produced at Fermilab. A 222 Ton prototype NOvA detector (NDOS) was built and operated in the neutrino beam for over a year to understand the response of the detector and its construction. The goal of this thesis is to study the muon neutrino interaction data collected in this test, specifically the identification of quasi-elastic charged-current interactions and measure the behavior of the quasi-elastic muon neutrino cross section. This thesis presents the analysis of the data from two detector configurations, the first configuration collected data from 1e19 protons on target (POT) from April to May 2011 and the second configuration collected data from 1.7e20POT from October 2011 to April 2012. The charged current quasi-elastic muon neutrino events collected with each configuration were analyzed to extract the cross section as a function of energy as well as the single differential cross sections with respect to outgoing muon momentum, outgoing muon angle from the incident neutrino direction; and the momentum dP, and transfer squared of the interaction.
Relativistic electron scattering from a freely movable proton in a strong laser field
NASA Astrophysics Data System (ADS)
Liu, Ai-Hua; Li, Shu-Min
2014-11-01
We study the electron scattering from the freely movable spin-1/2 proton in the presence of a linearly polarized laser field in the first Born approximation. The dressed state of the electron is described by a time-dependent wave function derived from a perturbation treatment (in a laser field). With the aid of numerical results we explore the dependencies of the differential cross section (DCS) on the electron-impact energy. Due to the mobility of the target, the DCS of this process is modified compared to the Mott scattering, especially in large scattering angles.
Devaney, J.J.
1982-04-01
The importance of single, large-angle, nuclear-coulombic, nuclear-hadronic, hadronic-coulombic interference, and multiple nuclear-coulombic scattering is investigated for tritons incident on deuterium, iron, and plutonium for very high temperatures and densities and for ordinary liquid and solid densities at low temperature. Depending on the accuracy desired, we conclude that for 10-keV-temperature DT plasmas it is not necessary to include elastic scattering deflection in reaction-in-flight calculations. For higher temperatures or where angular accuracies greater than 10/sup 0/ are significant or for higher Z targets or for other special circumstances, one must include elastic scattering from coulomb forces.
NASA Astrophysics Data System (ADS)
Magazù, Salvatore; Maisano, Giacomo; Migliardo, Federica; Benedetto, Antonio
2009-04-01
In the present paper we first focus on the role of the instrumental resolution in elastic incoherent neutron scattering (EINS) where the connection between the self-distribution function (SDF) and the measured EINS intensity profile is highlighted. Second we show how the SDF procedure, previously introduced, allows both the total and the partial mean-square displacement evaluations through the total and the partial SDFs. Finally, we compare the SDF and the Gaussian procedures, by applying the two approaches to EINS data collected, by the IN13 backscattering spectrometer (Institute Laue-Langevin, Grenoble), on aqueous mixtures of two homologous disaccharides, i.e., sucrose and trehalose, and on myoglobin.
NASA Astrophysics Data System (ADS)
Magazú, Salvatore; Maisano, Giacomo; Migliardo, Federica; Galli, Giovanni; Benedetto, Antonio; Morineau, Denis; Affouard, F.; Descamps, M.
2008-10-01
In the present work the role played by the instrumental resolution function in elastic incoherent neutron scattering (EINS) experiment is discussed. An important result consists in the definition of an equivalent time t*, which depends both on the characteristic system time and on the resolution time, for which the spatial Fourier transform of EINS intensity profile and the self-distribution function (SDF) evaluated at t =t* are proportional. Then the equivalent time t* is introduced in the SDF procedure, an operational recipe for the mean square displacement determination. The new revised procedure is applied on data of myoglobin in trehalose dry environment and of hydrated homologous disaccharides (sucrose and trehalose).
Scattering resonance of elastic wave and low-frequency equivalent slow wave
NASA Astrophysics Data System (ADS)
Meng, X.; Liu, H.; Hu, T.; Yang, L.
2015-12-01
Transmitted wave occurs as fast p-wave and slow p-wave in certain conditions when seismic waves travel through inhomogeneous layers. Energy of slow p-waves is strongest at some frequency band, but rather weak at both high frequency band and low frequency band, called scattering resonance. For practical seismic exploration, the frequency of slow p-wave occurs is below 10Hz, which cannot be explained by Biot's theory which predicts existence of the slow p-wave at ultrasonic band in the porous media. The slow p-wave equation have been derived, but which only adapted to explaining slow p-wave in the ultrasonic band. Experimental observations exhibit that slow p-wave also exists in nonporous media but with enormous low-velocity interbeds. When vertical incidence, elastic wave is simplified as compressing wave, the generation of slow waves is independent on shear wave. In the case of flat interbed and gas bubble, Liu (2006) has studied the transmission of acoustic waves, and found that the slow waves below the 10Hz frequency band can be explained. In the case of general elastic anisotropy medium, the tiheoretical research on the generation of slow waves is insufficient. Aiming at this problem, this paper presents an exponential mapping method based on transmitted wave (Magnus 1954), which can successfully explain the generation of the slow wave transmission in that case. Using the prediction operator (Claerbout 1985) to represent the transmission wave, this can be derived as first order partial differential equation. Using expansions in the frequency domain and the wave number domain, we find that the solutions have different expressions in the case of weak scattering and strong scattering. Besides, the method of combining the prediction operator and the exponential map is needed to extend to the elastic wave equation. Using the equation (Frazer and Fryer 1984, 1987), we derive the exponential mapping solution for the prediction operator of the general elastic medium
Elastic scattering of {sup 9}Li on {sup 208}Pb at energies around the Coulomb barrier
Cubero, M.; Fernandez-Garcia, J. P.; Alvarez, M. A. G.; Lay, J. A.; Moro, A. M.; Acosta, L.; Martel, I.; Sanchez-Benitez, A. M.; Alcorta, M.; Borge, M. J. G.; Tengblad, O.; Buchmann, L.; Shotter, A.; Walden, P.; Diget, D. G.; Fulton, B.; Fynbo, H. O. U.; Galaviz, D.; Gomez-Camacho, J.; Mukha, I.
2011-10-28
We have studied the dynamical effects of the halo structure of {sup 11}Li on the scattering on heavy targets at energies around the Coulomb barrier. This experiment was performed at ISAC-II at TRIUMF with a world record in production of the post-accelerated {sup 11}Li beam. As part of this study we report here on the first measurement of the elastic cross section of the core nucleus, i.e. {sup 9}Li on {sup 208}Pb, at energies around the Coulomb barrier. A preliminary optical model analysis has been performed in order to extract a global optical potential to describe the measured angular distributions.
Chiral symmetry, constituent quarks and quasi-elastic electron-nucleus scattering
NASA Astrophysics Data System (ADS)
Henley, E. M.; Krein, G.
1989-11-01
The effects of chiral symmetry breaking are examined for quasi-elastic electron scattering on nuclei. Nucleons are assumed to be composed of constituent quarks with masses that depend on density. This density dependence is determined on the basis of the Nambu-Jona-Lasinio model. It is found that the effects of chiral symmetry breaking are in the right direction and the right order of magnitude to explain the discrepancies between theory and experiment. On leave from Departamento de Fisica, Universidade Federal de Santa Maria, 97100 Santa Maria, R.S., Brazil.
Double Folding Potential of Different Interaction Models for 16O + 12C Elastic Scattering
NASA Astrophysics Data System (ADS)
Hamada, Sh.; Bondok, I.; Abdelmoatmed, M.
2016-08-01
The elastic scattering angular distributions for 16O + 12C nuclear system have been analyzed using double folding potential of different interaction models: CDM3Y1, CDM3Y6, DDM3Y1 and BDM3Y1. We have extracted the renormalization factor N r for the different concerned interaction models. Potential created by BDM3Y1 model of interaction has the shallowest depth which reflects the necessity to use higher renormalization factor. The experimental angular distributions for 16O + 12C nuclear system in the energy range 115.9-230 MeV exhibited unmistakable refractive features and rainbow phenomenon.
Effect of Dzyaloshinski-Moriya interaction on elastic small-angle neutron scattering
NASA Astrophysics Data System (ADS)
Michels, Andreas; Mettus, Denis; Honecker, Dirk; Metlov, Konstantin L.
2016-08-01
For magnetic materials containing many lattice imperfections (e.g., nanocrystalline magnets), the relativistic Dzyaloshinski-Moriya (DM) interaction may result in nonuniform spin textures due to the lack of inversion symmetry at interfaces. Within the framework of the continuum theory of micromagnetics, we explore the impact of the DM interaction on the elastic magnetic small-angle neutron scattering (SANS) cross section. It is shown that the DM interaction gives rise to a polarization-dependent asymmetric term in the spin-flip SANS cross section. Analysis of this feature may provide a means to determine the DM constant.
Elastic scattering for the system {sup 6}Li+p at near barrier energies with MAGNEX
Soukeras, V.; Pakou, A.; Sgouros, O.; Cappuzzello, F.; Bondi, M.; Nicolosi, D.; Acosta, L.; Marquinez-Duran, G.; Martel, I.; Agodi, C.; Carbone, D.; Cavallaro, M.; Cunsolo, A.; Di Pietro, A.; Fernández-García, J. P.; Figuera, P.; Fisichella, M.; Alamanos, N.; De Napoli, M.; Foti, A.; and others
2015-02-24
Elastic scattering measurements have been performed for the {sup 6}Li+p system in inverse kinematics at the energies of 16, 20, 25 and 29 MeV. The heavy ejectile was detected by the large acceptance MAGNEX spectrometer at the Laboratori Nazionali del Sud (LNS) in Catania, in the angular range between ∼2{sup 0} and 12{sup 0} in the laboratory system, giving us the possibility to span almost a full angular range in the center of mass system. Results will be presented and discussed for one of the energies.
David Abbott; Abdellah Ahmidouch; Heinz Anklin; Francois Arvieux; Jacques Ball; S. Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; James Dunne; Lars Ewell; Laurent Eyraud; Christophe Furget; Michel Garcon; Ronald Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; Adrian Honegger; Juerg Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; David Mack; Pete Markowitz; Justin McIntyre; David Meekins; Fernand Merchez; Joseph Mitchell; R. Mohring; Sekazi Mtingwa; Hamlet Mkrtchyan; David Pitz; Liming Qin; Ronald Ransome; Jean-Sebastien Real; Philip Roos; Paul Rutt; Reyad Sawafta; Samuel Stepanyan; Raphael Tieulent; Egle Tomasi-Gustafsson; William Turchinetz; Kelley Vansyoc; Jochen Volmer; Eric Voutier; William Vulcan; Claude Williamson; Stephen Wood; Chen Yan; Jie Zhao; Wenxia Zhao
2000-05-01
Tensor polarization observables (t20, t21 and t22) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 and 1.7 (GeV/c){sup 2}. The experiment was performed at the Jefferson Laboratory in Hall C using the electron HMS Spectrometer, a specially designed deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new data determine to much larger Q{sup 2} the deuteron charge form factors G{sub C} and G{sub Q}. They are in good agreement with relativistic calculations and disagree with pQCD predictions.
Elastic scattering research at a 1 MW long pulse spallation neutron source
Crawford, R.K.
1995-12-31
The elastic scattering working group investigated instrumentation for powder diffraction, single-crystal diffraction, small-angle diffraction, and reflectometry. For this purpose, three subgroups were formed; one for powder diffraction and single-crystal diffraction, one for small-angle diffraction, and one for reflectometry. For the most part these subgroups worked separately, but for part of the time the reflectometry and small-angle diffraction subgroups met together to discuss areas of common interest. Contributors in each of these subgroups are indicated below along with the discussion of these subgroup deliberations.
Tensor Analyzing Powers for Quasi-Elastic Electron Scattering from Deuterium
Z.-L. Zhou; M. Bouwhuis; M. Ferro-Luzzi; E. Passchier; R. Alarcon; M. Anghinolfi; H. Arenhoevel; R. van Bommel; T. Botto; J.F.J. van den Brand; H.J. Bulten; S. Choi; J. Comfort; S.M. Dolfini; R. Ent; C. Gaulard; D.W. Higinbotham; C.W. de Ja ger; E. Konstantinov; J. Lang; W. Leidemann; D.J. de Lange; M.A. Miller; D. Niko lenko; N. Papadakis; I. Passchier; H.R. Poolman; S.G. Popov; I. Rachek; M. Ripan i; E. Six; J.J.M. Steijger; M. Taiuti; O. Unal; N. Vodinas; H. de Vries
1999-01-01
We report on a first measurement of tensor analyzing powers in quasi-elastic electron-deuteron scattering at an average three-momentum transfer of 1.7 fm{sup -1}. Data sensitive to the spin-dependent nucleon density in the deuteron were obtained for missing momenta up to 150 MeV/c with a tensor polarized {sup 2}H target internal to an electron storage ring. The data are well described by a calculation that includes the effects of final-state interaction, meson-exchange and isobar currents, and leading-order relativistic contributions.
Short Range Correlations in Nuclei at Large xbj through Inclusive Quasi-Elastic Electron Scattering
Ye, Zhihong
2013-12-01
The experiment, E08-014, in Hall-A at Jefferson Lab aims to study the short-range correlations (SRC) which are necessary to explain the nuclear strength absent in the mean field theory. The cross sections for 2H, 3He, 4He, 12C, 40Ca and 48Ca, were measured via inclusive quasi-elastic electron scattering from these nuclei in a Q2 range between 0.8 and 2.8 (GeV/c)^{2} for x>1. The cross section ratios of heavy nuclei to 2H were extracted to study two-nucleon SRC for 1
Polf, Jerimy C.; Harvey, Mark C.; Smith, Alfred R.
2007-11-15
In passively scattered proton radiotherapy, a clinically useful treatment beam is produced by spreading a small proton 'pencil beam' extracted from the accelerator to create both a uniform dose profile laterally and a uniform spread-out Bragg peak (SOBP) in depth. Lateral spreading and range modulation of the beam are accomplished using specially designed components within the treatment delivery nozzle. The purpose of this study was to determine how changes in the size of the initial proton pencil beam affect the delivery of dose with a passive scatter treatment nozzle. Monte Carlo calculations were used to study changes of the beam's in-air energy distribution at the exit of the nozzle and the central axis depth dose profiles in water resulting from changes in the incident beam size. Our results indicate that the width of the delivered SOBP decreases as the size of the initial beam increases.
NASA Astrophysics Data System (ADS)
Lu, C.; Mao, Z.; Lin, J.; Prakapenka, V.
2011-12-01
Iron-containing pyrope ((Fe,Mg)3Al2Si3O12)) is believed to be an abundant rock-forming mineral in the Earth's interior, ranging from the crust to the top of the lower mantle. Based on the pyrolite mineralogical model, pyrope accounts for 13% by volume in the upper mantle and 10% in the transition zone. Therefore, laboratory measurements on the elasticity of pyrope at relevant pressure and temperature conditions are critical in understanding the seismic images and in constraining the chemistry and mineralogy of the region. The elasticity of single-crystal pyrope has been studied up to 20 GPa at 300 K and up to 1100 K at 1 bar, yet it has never been investigated at simultaneous high pressure-temperature conditions. Thus, much of our knowledge of the upper mantle and transition zone seismic profiles largely relies on extrapolated experimental results or theoretical calculations. Here we have measured the single-crystal elasticity of garnet, ((Mg2.04Ca0.16Fe0.74)Al2.02(SiO4)3) up to 20 GPa and 750 K using combined Brillouin scattering and synchrontron X-ray diffraction in an externally-heated diamond anvil cell at GSECARS of the Advanced Photon Source, Argonne National Laboratory. We have derived full elastic constants (Cij) of the sample as a function of pressure and temperature at relevant conditions of the deep mantle. The temperature derivatives of the Cijs are similar to that at ambient pressure, indicating a minimal pressure effect. Together with the elasticity of other major mantle minerals, we have used a thermoelastic model to reconstruct the seismic velocity profile of the upper mantle and the transition zone and to reference the mineralogy of the regions.
NASA Astrophysics Data System (ADS)
Chaiken, Joseph; Goodisman, Jerry; Deng, Bin; Bussjager, Rebecca J.; Shaheen, George
2009-09-01
We report simultaneous observation of elastic scattering, fluorescence, and inelastic scattering from in vivo near-infrared probing of human skin. Careful control of the mechanical force needed to obtain reliable registration of in vivo tissue with an appropriate optical system allows reproducible observation of blood flow in capillary beds of human volar side fingertips. The time dependence of the elastically scattered light is highly correlated with that of the combined fluorescence and Raman scattered light. We interpret this in terms of turbidity (the impeding effect of red blood cells on optical propagation to and from the scattering centers) and the changes in the volume percentages of the tissues in the irradiated volume with normal homeostatic processes. By fitting to a model, these measurements may be used to determine volume fractions of plasma and RBCs.
Osti, Naresh C.; Mamontov, Eugene; Ramirez-cuesta, A.; Wesolowski, David J.; Diallo, S. O.
2015-12-10
Understanding the molecular behavior of water in spatially restricted environments is important to better understanding its role in many biological, chemical and geological processes. Here we examine the translational diffusion of water confined to a variety of substrates, from flat surfaces to nanoporous media, in the context of a recently proposed universal scaling law (Chiavazzo 2014) [1]. Using over a dozen previous neutron scattering results, we test the validity of this law, evaluating separately the influence of the hydration amount, and the effects of the size and morphology of the confining medium. Additionally, we investigate the effects of changing instrument resolutions and fitting models on the applicability of this law. Finally, we perform quasi-elastic neutron scattering measurements on water confined inside nanoporous silica to further evaluate this predictive law, in the temperature range 250≤T≤290 K.
Osti, Naresh C.; Mamontov, Eugene; Ramirez-cuesta, A.; Wesolowski, David J.; Diallo, S. O.
2015-12-10
Understanding the molecular behavior of water in spatially restricted environments is important to better understanding its role in many biological, chemical and geological processes. Here we examine the translational diffusion of water confined to a variety of substrates, from flat surfaces to nanoporous media, in the context of a recently proposed universal scaling law (Chiavazzo 2014) [1]. Using over a dozen previous neutron scattering results, we test the validity of this law, evaluating separately the influence of the hydration amount, and the effects of the size and morphology of the confining medium. Additionally, we investigate the effects of changing instrumentmore » resolutions and fitting models on the applicability of this law. Finally, we perform quasi-elastic neutron scattering measurements on water confined inside nanoporous silica to further evaluate this predictive law, in the temperature range 250≤T≤290 K.« less
Spin-correlation coefficients and phase-shift analysis for p+{sup 3}He elastic scattering
Daniels, T. V.; Arnold, C. W.; Cesaratto, J. M.; Clegg, T. B.; Couture, A. H.; Karwowski, H. J.; Katabuchi, T.
2010-09-15
Angular distributions for the target spin-dependent observables A{sub 0y}, A{sub xx}, and A{sub yy} have been measured using polarized proton beams at several energies between 2 and 6 MeV and a spin-exchange optical pumping polarized {sup 3}He target. These measurements have been included in a global phase-shift analysis following that of E. A. George and L. D. Knutson [Phys. Rev. C 67, 027001 (2003)], who reported two best-fit phase-shift solutions to the previous global p+{sup 3}He elastic-scattering database below 12 MeV. These new measurements, along with measurements of cross-section and beam-analyzing power made over a similar energy range by B. M. Fisher et al. [Phys. Rev. C 74, 034001 (2006)], allowed a single, unique solution to be obtained. The new measurements and phase shifts are compared with theoretical calculations using realistic nucleon-nucleon potential models.
Trantham, E.C.; Rorschach, H.E.; Clegg, J.S.; Hazlewood, C.F.; Nicklow, R.M.; Wakabayashi, N.
1984-05-01
Results have been obtained on the quasi-elastic spectra of neutrons scattered from pure water, 20% agarose gel (hydration four grams H/sub 2/O per gram of dry solid) and cysts of the brine shrimp Artemia for hydrations between 0.10 and 1.2 grams H/sub 2/O per gram of dry solids. The spectra were interpreted using a two-component model that included contributions from the covalently bonded protons and the hydration water, and a mobile water fraction. The mobile fraction was described by a jump-diffusion correlation function for the translation motion and a simple diffusive orientational correlation function. The results for the line widths ..gamma..(Q/sup 2/) for pure water were in good agreement with previous measurements. The agarose results were consistent with NMR measurements that show a slightly reduced translational diffusion for the mobile water fraction. The Artemia results show that the translational diffusion coefficient of the mobile water fraction was greatly reduced from that of pure water. The line width was determined mainly by the rotational motion, which was also substantially reduced from the pure water value as determined from dielectric relaxation studies. The translational and rotational diffusion parameters were consistent with the NMR measurements of diffusion and relaxation. Values for the hydration fraction and the mean square thermal displacement as determined from the Q-dependence of line areas were also obtained.
High-energy pp and pp-bar forward elastic scattering and total cross sections
Block, M.M.; Cahn, R.N.
1985-04-01
The present status of elastic pp and pp-bar scattering in the high-energy domain is reviewed, with emphasis on the forward and near-forward regions. The experimental techniques for measuring sigma/sub tot/, rho, and B are discussed, emphasizing the importance of the region in which the nuclear and Coulomb scattering interfere. The impact-parameter representation is exploited to give simple didactic demonstrations of important rigorous theorems based on analyticity, and to illuminate the significance of the slope parameter B and the curvature parameter C. Models of elastic scattering are discussed, and a criterion for the onset of ''asymptopia'' is given. A critique of dispersion relations is presented. Simple analytic functions are used to fit simultaneously the real and imaginary parts of forward scattering amplitudes for both pp and pp-bar, obtained from experimental data for sigma/sub tot/ and rho. It is found that a good fit can be obtained using only five parameters (with a cross section rising as ln/sup 2/s), over the energy range 5 < ..sqrt..s < 62 GeV. The possibilities that (a) the cross section rises only as lns, (b) the cross section rises only locally as ln/sup 2/s, and eventually goes to a constant value, and (c) the cross-section difference between pp and pp-bar does not vanish as s..-->..infinity are examined critically. The nuclear slope parameters B are also fitted in a model-independent fashion. Examination of the fits reveals a new regularity of the pp-bar and the pp systems.
Optical elastic scattering for early label-free identification of clinical pathogens
NASA Astrophysics Data System (ADS)
Genuer, Valentin; Gal, Olivier; Méteau, Jérémy; Marcoux, Pierre; Schultz, Emmanuelle; Lacot, Éric; Maurin, Max; Dinten, Jean-Marc
2016-03-01
We report here on the ability of elastic light scattering in discriminating Gram+, Gram- and yeasts at an early stage of growth (6h). Our technique is non-invasive, low cost and does require neither skilled operators nor reagents. Therefore it is compatible with automation. It is based on the analysis of the scattering pattern (scatterogram) generated by a bacterial microcolony growing on agar, when placed in the path of a laser beam. Measurements are directly performed on closed Petri dishes. The characteristic features of a given scatterogram are first computed by projecting the pattern onto the Zernike orthogonal basis. Then the obtained data are compared to a database so that machine learning can yield identification result. A 10-fold cross-validation was performed on a database over 8 species (15 strains, 1906 scatterograms), at 6h of incubation. It yielded a 94% correct classification rate between Gram+, Gram- and yeasts. Results can be improved by using a more relevant function basis for projections, such as Fourier-Bessel functions. A fully integrated instrument has been installed at the Grenoble hospital's laboratory of bacteriology and a validation campaign has been started for the early screening of MSSA and MRSA (Staphylococcus aureus, methicillin-resistant S. aureus) carriers. Up to now, all the published studies about elastic scattering were performed in a forward mode, which is restricted to transparent media. However, in clinical diagnostics, most of media are opaque, such as blood-supplemented agar. That is why we propose a novel scheme capable of collecting back-scattered light which provides comparable results.
Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D
2016-01-14
We measured differential cross sections for elastic (rotationally integrated) electron scattering on pyrimidine, both as a function of angle up to 180(∘) at electron energies of 1, 5, 10, and 20 eV and as a function of electron energy in the range 0.1-14 eV. The experimental results are compared to the results of the fixed-nuclei Schwinger variational and R-matrix theoretical methods, which reproduce satisfactorily the magnitudes and shapes of the experimental cross sections. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. Resonant structures are observed at 0.2, 0.7, and 4.35 eV and calculations for different symmetries confirm their assignment as the X̃(2)A2, Ã(2)B1, and B̃(2)B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B̃(2)B1 shape resonance appears as a peak, a dip, or a step function in the cross sections recorded as a function of energy at different scattering angles and this effect is satisfactorily reproduced by theory. The dip and peak contributions at different scattering angles partially compensate, making the resonance nearly invisible in the integral cross section. Vibrationally integrated cross sections were also measured at 1, 5, 10 and 20 eV and the question of whether the fixed-nuclei cross sections should be compared to vibrationally elastic or vibrationally integrated cross section is discussed.
Probing Proton Strangeness with Time-Like Virtual Compton Scattering
Stephen R. Cotanch; Robert A. Williams
2002-05-01
We document that p(gamma,e+e-)p measurements will yield new, important information about the off-shell time-like nucleon form factors, especially in the phi meson region (q{sup 2} = M{sup 2}{sub {phi}}) governing the phi N couplings g{sup V,T}{sub {phi}NN}. Calculations for p(gamma,e+e-)p, utilizing vector meson dominance, predict measurable phi enhancements at high |t| compared to the expected phi background production from pi, eta and Pomeron exchange. The phi form factor contribution generates a novel experimental signature for OZI violation and the proton strangeness content. The phi N couplings are determined independently from a combined analysis of the neutron electric form factor and recent high |t| phi photoproduction. The pi, eta and Pomeron transition form factors are also predicted and the observed pi and eta transition moments are reproduced.
Spin observables in proton-deuteron scattering and T-invariance test
Temerbayev, A. A.; Uzikov, Yu. N.
2015-01-15
The total cross section for the interaction of transversely polarized protons p{sub p}{sup y} and deuterons that have a tensor polarization P{sub x}{sup z} provides a null-test signal of T-invariance violation under the condition of P invariance. The relevant experiment is planned by the PAX Collaboration at the COSY accelerator with protons accelerated to the energy of 135 MeV. A modified Glauber theory is used here to calculate the differential spin observables A{sub y}, C{sub y,y}, C{sub xz,y}, C{sub z,x}, and C{sub x,z} and the differential and total cross sections for proton-deuteron scattering in the case of T-even P-even proton-nucleon interactions. This makes it possible to estimate background conditions of the planned experiment.
Elastic Electron Scattering by Laser-Excited (sup 138)Ba (...6s6p (sup 1)P(sub 1)) Atoms
NASA Technical Reports Server (NTRS)
Csanak, G.
1997-01-01
The result of a joint experimental and theoretical study concerning elastic electron scattering by laser-excited (sup 138)Ba (...6s6p (sup 1)P(sub 1)) atoms are presented. From these studies, we extracted differential scattering cross sections (DCS's) and collision parameters for elastic scattering by the coherently prepared (sup 1)P(sub 1) atoms.
Elastic light single-scattering spectroscopy for detection of dysplastic tissues
NASA Astrophysics Data System (ADS)
Canpolat, Murat; Denkçeken, Tuba; Akman, Ayşe.; Alpsoy, Erkan; Tuncer, Recai; Akyüz, Mahmut; Baykara, Mehmet; Yücel, Selçuk; Başsorgun, Ibrahim; ćiftçioǧlu, M. Akif; Gökhan, Güzide Ayşe.; Gürer, ElifInanç; Peştereli, Elif; Karaveli, Šeyda
2013-11-01
Elastic light single-scattering spectroscopy (ELSSS) system has been developed and tested in diagnosis of cancerous tissues of different organs. ELSSS system consists of a miniature visible light spectrometer, a single fiber optical probe, a halogen tungsten light source and a laptop. Measurements were performed on excised brain, skin, cervix and prostate tumor specimens and surrounding normal tissues. Single fiber optical probe with a core diameter of 100 μm was used to deliver white light to and from tissue. Single optical fiber probe mostly detects singly scattered light from tissue rather than diffused light. Therefore, measured spectra are sensitive to size of scatters in tissue such as cells, nuclei, mitochondria and other organelles of cells. Usually, nuclei of tumor cells are larger than nuclei of normal cells. Therefore, spectrum of singly scattered light of tumor tissue is different than normal tissue. The spectral slopes were shown to be positive for normal brain, skin and prostate and cervix tissues and negative for the tumors of the same tissues. Signs of the spectral slopes were used as a discrimination parameter to differentiate tumor from normal tissues for the three organ tissues. Sensitivity and specificity of the system in differentiation between tumors from normal tissues were 93% and %100 for brain, 87% and 85% for skin, 93.7% and 46.1% for cervix and 98% and 100% for prostate.
Elastic and inelastic neutron scattering cross sections for fission reactor applications
NASA Astrophysics Data System (ADS)
Hicks, S. F.; Chakraborty, A.; Combs, B.; Crider, B. P.; Downes, L.; Girgis, J.; Kersting, L. J.; Kumar, A.; Lueck, C. J.; McDonough, P. J.; McEllistrem, M. T.; Peters, E. E.; Prados-Estevz, F. M.; Schniederjan, J.; Sidwell, L.; Sigillito, A. J.; Vanhoy, J. R.; Watts, D.; Yates, S. W.
2013-04-01
Nuclear data important for the design and development of the next generation of light-water reactors and future fast reactors include neutron elastic and inelastic scattering cross sections on important structural materials, such as Fe, and on coolant materials, such as Na. These reaction probabilities are needed since neutron reactions impact fuel performance during irradiations and the overall efficiency of reactors. While neutron scattering cross sections from these materials are available for certain incident neutron energies, the fast neutron region, particularly above 2 MeV, has large gaps for which no measurements exist, or the existing uncertainties are large. Measurements have been made at the University of Kentucky Accelerator Laboratory to measure neutron scattering cross sections on both Fe and Na in the region where these gaps occur and to reduce the uncertainties on scattering from the ground state and first excited state of these nuclei. Results from measurements on Fe at incident neutron energies between 2 and 4 MeV will be presented and comparisons will be made to model calculations available from data evaluators.
Inelastic Proton Scattering on 21Na in Inverse Kinematics
NASA Astrophysics Data System (ADS)
Austin, Roby
2009-10-01
R.A.E. Austin, R. Kanungo, S. Reeve, Saint Mary's University; D.G. Jenkins, C.Aa.Diget, A. Robinson, A.G. Tuff, O. Roberts, University of York, UK; P.J. Woods, T. Davinson, G. J. Lotay, University of Edinburgh; C.-Y. Wu, Lawrence Livermore National Laboratory; H. Al Falou, G.C. Ball, M. Djongolov, A. Garnsworthy, G. Hackman, J.N. Orce, C.J. Pearson, S. Triambak, S.J. Williams, TRIUMF; C. Andreiou, D.S. Cross, N. Galinski, R. Kshetri, Simon Fraser University; C. Sumithrarachchi, M.A. Schumaker, University of Guelph; M.P. Jones, S.V. Rigby, University of Liverpool; D. Cline, A. Hayes, University of Rochester; T.E. Drake, University of Toronto; We describe an experiment and associated technique [1] to measure resonances of interest in astrophysical reactions. At the TRIUMF ISAC-II radioactive beam accelerator facility in Canada, particles inelastically scattered in inverse kinematics are detected with Bambino, a δE-E silicon telescope spanning 15-40 degrees in the lab. We use the TIGRESS to detect gamma rays in coincidence with the charged particles to cleanly select inelastic scattering events. We measured resonances above the alpha threshold in ^22Mg of relevance to the rate of break-out from the hot-CNO cycle via the reaction ^ 18Ne(α,p)^21Na. [1] PJ Woods et al. Rex-ISOLDE proposal 424 Cern (2003).
Electromagnetic radiative corrections in parity-violating electron-proton scattering
Arvieux, Francois; Collin, B.; Guler, Hayko; Morlet, Marcel; Niccolai, Silvia; Ong, S.; Van de Wiele, Jacques
2006-01-01
QED radiative corrections have been calculated for leptonic and hadronic variables in parity-violating elastic ep scattering. For the first time, the calculation of the asymmetry in the elastic radiative tail is performed without the peaking-approximation assumption in hadronic variables configuration. A comparison with the PV-A4 data validates our approach. This method has been also used to evaluate the radiative corrections to the parity-violating asymmetry measured in the G0 experiment. The results obtained are here presented.
Chen, Wei-kang; Fang, Hui
2016-03-01
The basic principle of polarization-differentiation elastic light scattering spectroscopy based techniques is that under the linear polarized light incidence, the singlely scattered light from the superficial biological tissue and diffusively scattered light from the deep tissue can be separated according to the difference of polarization characteristics. The novel point of the paper is to apply this method to the detection of particle suspension and, to realize the simultaneous measurement of its particle size and number density in its natural status. We design and build a coaxial cage optical system, and measure the backscatter signal at a specified angle from a polystyrene microsphere suspension. By controlling the polarization direction of incident light with a linear polarizer and adjusting the polarization direction of collected light with another linear polarizer, we obtain the parallel polarized elastic light scattering spectrum and cross polarized elastic light scattering spectrum. The difference between the two is the differential polarized elastic light scattering spectrum which include only the single scattering information of the particles. We thus compare this spectrum to the Mie scattering calculation and extract the particle size. We then also analyze the cross polarized elastic light scattering spectrum by applying the particle size already extracted. The analysis is based on the approximate expressions taking account of light diffusing, from which we are able to obtain the number density of the particle suspension. We compare our experimental outcomes with the manufacturer-provided values and further analyze the influence of the particle diameter standard deviation on the number density extraction, by which we finally verify the experimental method. The potential applications of the method include the on-line particle quality monitoring for particle manufacture as well as the fat and protein density detection of milk products.
Chen, Wei-kang; Fang, Hui
2016-03-01
The basic principle of polarization-differentiation elastic light scattering spectroscopy based techniques is that under the linear polarized light incidence, the singlely scattered light from the superficial biological tissue and diffusively scattered light from the deep tissue can be separated according to the difference of polarization characteristics. The novel point of the paper is to apply this method to the detection of particle suspension and, to realize the simultaneous measurement of its particle size and number density in its natural status. We design and build a coaxial cage optical system, and measure the backscatter signal at a specified angle from a polystyrene microsphere suspension. By controlling the polarization direction of incident light with a linear polarizer and adjusting the polarization direction of collected light with another linear polarizer, we obtain the parallel polarized elastic light scattering spectrum and cross polarized elastic light scattering spectrum. The difference between the two is the differential polarized elastic light scattering spectrum which include only the single scattering information of the particles. We thus compare this spectrum to the Mie scattering calculation and extract the particle size. We then also analyze the cross polarized elastic light scattering spectrum by applying the particle size already extracted. The analysis is based on the approximate expressions taking account of light diffusing, from which we are able to obtain the number density of the particle suspension. We compare our experimental outcomes with the manufacturer-provided values and further analyze the influence of the particle diameter standard deviation on the number density extraction, by which we finally verify the experimental method. The potential applications of the method include the on-line particle quality monitoring for particle manufacture as well as the fat and protein density detection of milk products. PMID:27400522
Low energy elastic electron scattering from CF{sub 3}Br molecules
Hargreaves, L. R.; Brunton, J. R.; Maddern, T. M.; Brunger, M. J.
2015-03-28
CF{sub 3}Br is a potentially valuable precursor molecule for generating beams of gas phase Br radicals suitable for electron collisions studies. However, the utility of CF{sub 3}Br for this purpose depends critically on the availability of sound scattering cross sections to allow the contribution of the precursor to be isolated within the total scattering signal. To this end, here we present elastic differential cross section (DCS) measurements for CF{sub 3}Br at incident energies between 15 and 50 eV. Comparison of these DCSs to those from the only other available experimental study [Sunohara et al., J. Phys. B: At., Mol. Opt. Phys. 36, 1843 (2003)] and a Schwinger multichannel with pseudo potentials (SMCPPs) calculation [Bettega et al., J. Phys. B: At., Mol. Opt. Phys. 36, 1263 (2003)] shows generally a very good accord. Integral elastic and momentum transfer cross sections, derived from our DCSs, are also found to be in quite good agreement with the SMCPP results.
Theoretical Calculations of Elastic and Inelastic Scattering of Electrons from Ar^+
NASA Astrophysics Data System (ADS)
Griffin, D. C.; Pindzola, M. S.; Shaw, J. A.; Badnell, N. R.
1996-05-01
We report on theoretical calculations of differential and partial cross sections for elastic scattering of electrons from Ar^+ and total cross sections for electron-impact excitation and ionization of Ar^+. The elastic scattering calculations are performed using the R-matrix method and are compared to measurements. The excitation cross sections are calculated using both the distorted-wave and the R-matrix close-coupling approximations, while the ionization cross sections are determined from the distorted-wave approximation, and include the effects of final-state correlation. The effects of core polarization and resonance contributions on the excitation cross sections are examined carefully. Rate coefficients for ionization and excitation to the levels of 3p^44p ^4D, together with radiative rates from the levels of 3p^44p ^4D to all possible lower levels, will be entered into the ADAS collisional-radiative modeling codes(H. P. Summers \\underlineADAS User's Manual), JET-IR(94)06. Work supported by the Department of Energy to generate density-dependent parameters for use in the interpretation of on-going emissivity measurements from tokamak plasmas.
Experimental study of {sup 6}He+{sup 9}Be elastic scattering at low energies
Pires, K. C. C.; Lichtenthaeler, R.; Lepine-Szily, A.; Guimaraes, V.; Faria, P. N. de; Barioni, A.; Mendes Junior, D. R.; Morcelle, V.; Pampa Condori, R.; Morais, M. C.; Zamora, J. C.; Crema, E.; Moro, A. M.; Rodriguez-Gallardo, M.; Assuncao, M.; Shorto, J. M. B.; Mukherjee, S.
2011-06-15
New data for the {sup 6}He+{sup 9}Be reaction at E{sub lab}=16.2 and 21.3 MeV have been taken and analyzed. The effect of the collective couplings to the excited states of the target has been studied by means of coupled-channels calculations, using a double-folding potential for the bare interaction between the colliding nuclei, supplemented with a phenomenological imaginary part of Woods-Saxon type. In addition, three- and four-body continuum-discretized coupled-channels calculations have been performed to investigate the effect of the projectile breakup on the elastic scattering. Both effects, the coupling to target and projectile excited states, are found to affect significantly the elastic scattering. The trivial local polarization potential extracted from the continuum-discretized coupled-channels calculations indicates that continuum couplings produce a repulsive real part and a long-range imaginary part in the projectile-target interaction.
Models of the elastic x-ray scattering feature for warm dense aluminum
Starrett, Charles Edward; Saumon, Didier
2015-09-03
The elastic feature of x-ray scattering from warm dense aluminum has recently been measured by Fletcher et al. [Nature Photonics 9, 274 (2015)] with much higher accuracy than had hitherto been possible. This measurement is a direct test of the ionic structure predicted by models of warm dense matter. We use the method of pseudoatom molecular dynamics to predict this elastic feature for warm dense aluminum with temperatures of 1–100 eV and densities of 2.7–8.1g/cm^{3}. We compare these predictions to experiments, finding good agreement with Fletcher et al. and corroborating the discrepancy found in analyses of an earlier experiment of Ma et al. [Phys. Rev. Lett. 110, 065001 (2013)]. Lastly, we also evaluate the validity of the Thomas-Fermi model of the electrons and of the hypernetted chain approximation in computing the elastic feature and find them both wanting in the regime currently probed by experiments.
Models of the elastic x-ray scattering feature for warm dense aluminum
Starrett, Charles Edward; Saumon, Didier
2015-09-03
The elastic feature of x-ray scattering from warm dense aluminum has recently been measured by Fletcher et al. [Nature Photonics 9, 274 (2015)] with much higher accuracy than had hitherto been possible. This measurement is a direct test of the ionic structure predicted by models of warm dense matter. We use the method of pseudoatom molecular dynamics to predict this elastic feature for warm dense aluminum with temperatures of 1–100 eV and densities of 2.7–8.1g/cm3. We compare these predictions to experiments, finding good agreement with Fletcher et al. and corroborating the discrepancy found in analyses of an earlier experiment ofmore » Ma et al. [Phys. Rev. Lett. 110, 065001 (2013)]. Lastly, we also evaluate the validity of the Thomas-Fermi model of the electrons and of the hypernetted chain approximation in computing the elastic feature and find them both wanting in the regime currently probed by experiments.« less
Dorman, Mark Edward
2008-04-01
The Main Injector Neutrino Oscillation Search (MINOS) is a long baseline neutrino oscillation experiment based at the Fermi National Accelerator Laboratory (FNAL) in Chicago, Illinois. MINOS measures neutrino interactions in two large iron-scintillator tracking/sampling calorimeters; the Near Detector on-site at FNAL and the Far Detector located in the Soudan mine in northern Minnesota. The Near Detector has recorded a large number of neutrino interactions and this high statistics dataset can be used to make precision measurements of neutrino interaction cross sections. The cross section for charged-current quasi-elastic scattering has been measured by a number of previous experiments and these measurements disagree by up to 30%. A method to select a quasi-elastic enriched sample of neutrino interactions in the MINOS Near Detector is presented and a procedure to fit the kinematic distributions of this sample and extract the quasi-elastic cross section is introduced. The accuracy and robustness of the fitting procedure is studied using mock data and finally results from fits to the MINOS Near Detector data are presented.
Mourant, J.R.; Boyer, J.; Johnson, T.M.; Lacey, J.; Bigio, I.J.; Bohorfoush, A.; Mellow, M.
1995-03-01
The Los Alamos National Laboratory has continued the development of the Optical Biopsy System (OBS) for noninvasive, real-time in situ diagnosis of tissue pathologies. In proceedings of earlier SPIE conferences we reported on clinical measurements in the bladder, and we report here on recent results of clinical tests in the gastrointestinal tract. With the OBS, tissue pathologies are detected/diagnosed using spectral measurements of the elastic optical transport properties (scattering and absorption) of the tissue over a wide range of wavelengths. The use of elastic scattering as the key to optical tissue diagnostics in the OBS is based on the fact that many tissue pathologies, including a majority of cancer forms, exhibit significant architectural changes at the cellular and sub-cellular level. Since the cellular components that cause elastic scattering have dimensions typically on the order of visible to near-IR wavelengths, the elastic (Mie) scattering properties will be wavelength dependent. Thus, morphology and size changes can be expected to cause significant changes m an optical signature that is derived from the wavelength-dependence of elastic scattering. Additionally, the optical geometry of the OBS beneficially enhances its sensitivity for measuring absorption bands. The OBS employs a small fiber-optic probe that is amenable to use with any endoscope or catheter, or to direct surface examination, as well as interstitial needle insertion. Data acquistion/display time is <1 second.
NASA Astrophysics Data System (ADS)
Minato, Shohei; Ghose, Ranajit
2014-05-01
The inverse scattering of seismic waves can reveal the spatial distribution of the elastic compliances along a non-welded interface, such as a fracture surface. The spatial heterogeneity along the surface of a fracture is a key determinant for fracture-associated hydraulic properties. In this paper, we demonstrate that the inverse scattering solution can be successfully applied to the point source response of a subhorizontal fracture. In the scale of seismic exploration, it is more appropriate to consider spherical waves from a point source than plane waves. Further, from only the P-wave point source response it is possible to estimate both normal and tangential fracture compliances. The synthetic seismic wavefield due to a P-wave point source in a 2-D elastic medium was computed using a time-domain finite difference approach. On this spherical wave data set, the correct estimation of the position and dip of the non-welded interface was possible through reverse-time migration followed by least-square fitting of the maximum amplitude of the P-P reflection. In order to estimate the heterogeneity along the non-welded interface, we first extract the elastic wavefield at the interface position. The extrapolated wavefield is then rotated such that the horizontal axis aligns along the fracture plane. Next, using this extrapolated and rotated wavefield, we solve the linear-slip boundary condition to obtain the distribution of normal and tangential compliances. Our result shows that the estimates of normal compliance are very accurate around the dominant frequency of the incident seismic wavefield. At lower frequencies, the estimated compliance distribution is less accurate and rather smooth due to the presence of evanescent waves. Extracting the distribution of the tangential compliance requires a larger stabilization factor. For a correct estimation of the tangential compliance, one needs S-wave sources or multiple sources providing more grazing angles to avoid the shadow
Multilevel fast multipole algorithm for elastic wave scattering by large three-dimensional objects
NASA Astrophysics Data System (ADS)
Tong, Mei Song; Chew, Weng Cho
2009-02-01
Multilevel fast multipole algorithm (MLFMA) is developed for solving elastic wave scattering by large three-dimensional (3D) objects. Since the governing set of boundary integral equations (BIE) for the problem includes both compressional and shear waves with different wave numbers in one medium, the double-tree structure for each medium is used in the MLFMA implementation. When both the object and surrounding media are elastic, four wave numbers in total and thus four FMA trees are involved. We employ Nyström method to discretize the BIE and generate the corresponding matrix equation. The MLFMA is used to accelerate the solution process by reducing the complexity of matrix-vector product from O(N2) to O(NlogN) in iterative solvers. The multiple-tree structure differs from the single-tree frame in electromagnetics (EM) and acoustics, and greatly complicates the MLFMA implementation due to the different definitions for well-separated groups in different FMA trees. Our Nyström method has made use of the cancellation of leading terms in the series expansion of integral kernels to handle hyper singularities in near terms. This feature is kept in the MLFMA by seeking the common near patches in different FMA trees and treating the involved near terms synergistically. Due to the high cost of the multiple-tree structure, our numerical examples show that we can only solve the elastic wave scattering problems with 0.3-0.4 millions of unknowns on our Dell Precision 690 workstation using one core.
NASA Astrophysics Data System (ADS)
He, J. J.; Kubono, S.; Teranishi, T.; Notani, M.; Baba, H.; Nishimura, S.; Moon, J. Y.; Nishimura, M.; Iwasaki, H.; Yanagisawa, Y.; Hokoiwa, N.; Kibe, M.; Lee, J. H.; Kato, S.; Gono, Y.; Lee, C. S.
2007-11-01
Proton resonant states in Al23 have been investigated for the first time by the resonant elastic and inelastic scattering of Mg22+p with a Mg22 beam at 4.38 MeV/nucleon bombarding a thick (CH2)n target. The low-energy Mg22 beam was separated by the CNS radioactive ion beam separator (CRIB). The energy spectra of recoiled protons were measured at average scattering angles of θlab≈4°,17° and 23°. A new state has been observed at Ex=3.00 MeV with a spin-parity assignment of (3/2+). In addition, resonant inelastic scattering has populated three more states at excitation energies of 3.14, 3.26, and 3.95 MeV, with proton decay to the first excited state in Mg22 being observed. The new state at 3.95 MeV has been assigned a spin-parity of Jπ=(7/2+). The resonant parameters were determined by an R-matrix analysis of the excitation functions with a SAMMY-M6-BETA code. The core-excited structure of Al23 is discussed within a shell-model picture. The stellar reaction rate of the Mg22(p,γ)Al23 reaction has been reevaluated, and the revised total reaction rate is about 40% greater than the previous result for temperatures beyond T9=0.3.
Deeply virtual Compton scattering on longitudinally polarized protons and neutrons at CLAS
Silvia Niccolai
2012-04-01
This paper focuses on a measurement of deeply virtual Compton scattering (DVCS) performed at Jefferson Lab using a nearly-6-GeV polarized electron beam, two longitudinally polarized (via DNP) solid targets of protons (NH{sub 3}) and deuterons (ND{sub 3}) and the CEBAF Large Acceptance Spectrometer. Here, preliminary results for target-spin asymmetries and double (beam-target) asymmetries for proton DVCS, as well as a very preliminary extraction of beam-spin asymmetry for neutron DVCS, are presented and linked to Generalized Parton Distributions.
Role of triple phonon excitations in large angle quasi-elastic scattering of very heavy mass systems
NASA Astrophysics Data System (ADS)
Zamrun, Muhammad Firihu
2016-07-01
We study the effect of multi-phonon excitations on large-angle quasi-elastic scattering of massive systems using the full order coupled-channels formalism. We especially investigate the role of triple phonon excitations of the target and projectile nuclei on the quasi-elastic scattering cross-section as well as the barrier distribution for 54Cr, 56Fe, 64Ni and 70Zn + 208Pb systems. It is shown that the calculations taken into account, the triple octupole phonon excitations of the target and triple quadrupole phonon excitations of the projectile for these systems can explain the experimental data of the quasi-elastic cross-section and the quasi-elastic barrier distribution. These results indicate that the coupled-channels formalism is still valid even for the very heavy mass systems.
Berlin, Asher; Hooper, Dan; McDermott, Samuel D.
2015-12-28
We consider a complete list of simplifieed models in which Majorana dark matter particles annihilate at tree level to hh or hZ finnal states, and calculate the loop-induced elastic scattering cross section with nuclei in each case. Expressions for these annihilation and elastic scattering cross sections are provided, and can be easily applied to a variety of UV complete models. We identify several phenomenologically viable scenarios, including dark matter that annihilates through the s-channel exchange of a spin-zero mediator or through the t-channel exchange of a fermion. Although the elastic scattering cross sections predicted in this class of models are generally quite small, XENON1Tand LZ should be sensitive to significant regions of this parameter space. Models in which the dark matter annihilates to hh or hZ can also generate a gamma-ray signal that is compatible with the excess observed from the Galactic Center.
Lohn, Andrew J.; Doyle, Barney L.; Stein, Gregory J.; Mickel, Patrick R.; Stevens, Jim E.; Marinella, Matthew J.
2014-04-03
We present a novel ion beam analysis technique combining Rutherford forward scattering and elastic recoil detection (RFSERD) and demonstrate its ability to increase efficiency in determining stoichiometry in ultrathin (5-50 nm) films as compared to Rutherford backscattering. In the conventional forward geometries, scattering from the substrate overwhelms the signal from light atoms but in RFSERD, scattered ions from the substrate are ranged out while forward scattered ions and recoiled atoms from the thin film are simultaneously detected in a single detector. Lastly, the technique is applied to tantalum oxide memristors but can be extended to a wide range of materialsmore » systems.« less
Lohn, Andrew J.; Doyle, Barney L.; Stein, Gregory J.; Mickel, Patrick R.; Stevens, Jim E.; Marinella, Matthew J.
2014-04-03
We present a novel ion beam analysis technique combining Rutherford forward scattering and elastic recoil detection (RFSERD) and demonstrate its ability to increase efficiency in determining stoichiometry in ultrathin (5-50 nm) films as compared to Rutherford backscattering. In the conventional forward geometries, scattering from the substrate overwhelms the signal from light atoms but in RFSERD, scattered ions from the substrate are ranged out while forward scattered ions and recoiled atoms from the thin film are simultaneously detected in a single detector. Lastly, the technique is applied to tantalum oxide memristors but can be extended to a wide range of materials systems.
NASA Astrophysics Data System (ADS)
Shi, F.; Lowe, M. J. S.; Xi, X.; Craster, R. V.
2016-07-01
We develop an elastodynamic theory to predict the diffuse scattered field of elastic waves by randomly rough surfaces, for the first time, with the aid of the Kirchhoff approximation (KA). Analytical expressions are derived incorporating surface statistics, to represent the expectation of the angular distribution of the diffuse intensity for different modes. The analytical solutions are successfully verified with numerical Monte Carlo simulations, and also validated by comparison with experiments. We then apply the theory to quantitatively investigate the effects of the roughness and the shear-to-compressional wave speed ratio on the mode conversion and the scattering intensity, from low to high roughness within the valid region of KA. Both the direct and the mode converted intensities are significantly affected by the roughness, which leads to distinct scattering patterns for different wave modes. The mode conversion effect is very strong around the specular angle and it is found to increase as the surface appears to be more rough. In addition, the 3D roughness induced coupling between the out-of-plane shear horizontal (SH) mode and the in-plane modes is studied. The intensity of the SH mode is shown to be very sensitive to the out-of-plane correlation length, being influenced more by this than by the RMS value of the roughness. However, it is found that the depolarization pattern for the diffuse field is independent of the actual value of the roughness.
Elastic neutron scattering at 96 MeV from 12 C and 208 Pb
NASA Astrophysics Data System (ADS)
Klug, J.; Blomgren, J.; Ataç, A.; Bergenwall, B.; Hildebrand, A.; Johansson, C.; Mermod, P.; Nilsson, L.; Pomp, S.; Tippawan, U.; Elmgren, K.; Olsson, N.; Jonsson, O.; Prokofiev, A. V.; Renberg, P.-U.; Nadel-Turonski, P.; Dangtip, S.; Phansuke, P.; Österlund, M.; Le Brun, C.; Lecolley, J. F.; Lecolley, F. R.; Louvel, M.; Marie-Noury, N.; Schweitzer, C.; Eudes, Ph.; Haddad, F.; Lebrun, C.; Koning, A. J.; Ledoux, X.
2003-12-01
A facility for detection of scattered neutrons in the energy interval 50 130 MeV , SCANDAL, has recently been installed at the 20 180 MeV neutron beam line of the The Svedberg Laboratory, Uppsala. Elastic neutron scattering from 12 C and 208 Pb has been studied at 96 MeV in the 10° 70° interval. The achieved energy resolution, 3.7 MeV , is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated normalization uncertainty, 3% , is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. The results are compared with modern optical model predictions based on phenomenology or microscopic nuclear theory.
Elastic pion-nucleon scattering in chiral perturbation theory: A fresh look
NASA Astrophysics Data System (ADS)
Siemens, D.; Bernard, V.; Epelbaum, E.; Gasparyan, A.; Krebs, H.; Meißner, Ulf-G.
2016-07-01
Elastic pion-nucleon scattering is analyzed in the framework of chiral perturbation theory up to fourth order within the heavy-baryon expansion and a covariant approach based on an extended on-mass-shell renormalization scheme. We discuss in detail the renormalization of the various low-energy constants and provide explicit expressions for the relevant β functions and the finite subtractions of the power-counting breaking terms within the covariant formulation. To estimate the theoretical uncertainty from the truncation of the chiral expansion, we employ an approach which has been successfully applied in the most recent analysis of the nuclear forces. This allows us to reliably extract the relevant low-energy constants from the available scattering data at low energy. The obtained results provide clear evidence that the breakdown scale of the chiral expansion for this reaction is related to the Δ resonance. The explicit inclusion of the leading contributions of the Δ isobar is demonstrated to substantially increase the range of applicability of the effective field theory. The resulting predictions for the phase shifts are in an excellent agreement with the predictions from the recent Roy-Steiner-equation analysis of pion-nucleon scattering.
NASA Astrophysics Data System (ADS)
Viveros, U.; Sanchez-Sesma, F. J.; Luzon, F.
2001-12-01
The scattering of elastic waves by various types of cracks is an important engineering problem. From a physical point of view the question that arises is up to what degree will a local perturbation in a medium modifies the scattered wave field. For instance, in the seismic monitoring to enhance oil recovery (due to extensive presence of cracks and cavities) a crucial problem is to determine zones where there are physical property changes. Modelling such highly heterogeneous media is critical to increased production from oil and gas. In order to study scattering effects caused by arbitrary-shaped cracks a simplified indirect boundary element method (BEM) is used to compute the seismic response of a 3-D crack under incident elastic P and S waves. The method is based on the integral representation for scattered elastic waves using single layer boundary sources. This approach is called indirect BEM in the literature as the sources strengths should be obtained as an intermediate step. Scattered waves are constructed at the boundaries from which they radiate. Therefore, this method can be regarded as a numerical realization of Huygens' principle. Boundary conditions lead to a system of integral for boundary sources. A simplified discretization scheme is used. It is based on the approximate rectification of the surfaces involved using circles for the numerical and analytical integration of the exact Green's function for the unbounded elastic space. Radiation patterns for penny-shaped and croissant-shaped cracks are explored. The scattering effects of the elastic waves in a homogeneous isotropic infinite elastic medium with a 3-D crack are displayed in both frequency and time domains.
Parity Nonconservation in Proton-water Scattering at 800 MeV
DOE R&D Accomplishments Database
Nagle, D. E.; Bowman, J. D.; Carlini, R.; Mischke, R. E.; Frauenfelder, H.; Harper, R. W.; Yuan, V.; McDonald, A. B.; Talaga, R.
1982-01-01
A search has been made for parity nonconservation in the scattering of 800 MeV polarized protons from an unpolarized water target. The result is for the longitudinal asymmetry, A{sub L} = +(6.6 +- 3.2) x 10{sup -7}. Control runs with Pb, using a thickness which gave equivalent beam broadening from Coulomb multiple scattering, but a factor of ten less nuclear interactions than the water target, gave A{sub L} = -(0.5 +- 6.0) x 10{sup -7}.
Haycraft, James J
2009-12-01
The acoustic phonons of the epsilon polymorph of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo [5.5.0.0(5,9).0(3,11)] dodecane (epsilon-CL-20) have been studied using Brillouin scattering spectroscopy. Analysis of the acoustic phonon velocities allowed determination of the complete stiffness tensor for this energetic material. The results are compared to a theoretical determination of the epsilon-CL-20 elastic constants, bulk moduli, and shear moduli. The observed ordering of elastic constants, C(22)>C(33)>C(11), is noted to be different from other nitramine energetic materials. Finally, the elasticity of epsilon-CL-20 is compared to recently published reports on cyclotrimethylene trinitramine's (RDX) elasticity and the beta polymorph of cyclotetramethylene tetranitramine's (beta-HMX) elasticity. PMID:19968345
NASA Astrophysics Data System (ADS)
Haycraft, James J.
2009-12-01
The acoustic phonons of the epsilon polymorph of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo [5.5.0.05,9.03,11] dodecane (ɛ-CL-20) have been studied using Brillouin scattering spectroscopy. Analysis of the acoustic phonon velocities allowed determination of the complete stiffness tensor for this energetic material. The results are compared to a theoretical determination of the ɛ-CL-20 elastic constants, bulk moduli, and shear moduli. The observed ordering of elastic constants, C22>C33>C11, is noted to be different from other nitramine energetic materials. Finally, the elasticity of ɛ-CL-20 is compared to recently published reports on cyclotrimethylene trinitramine's (RDX) elasticity and the beta polymorph of cyclotetramethylene tetranitramine's (β-HMX) elasticity.
Fanelli, Cristiano Fanelli; Cisbani, Evarostp; Hamilton, David; Salme, G.; Wojtsekhowski, Bogdan B.
2014-03-01
A preliminary analysis of polarization-transfer data at large scattering angle (70°), obtained in an experiment of real Compton scattering on proton, performed in Hall-C of Jefferson Lab, is presented. It is also discussed the relevance of this kind of experiments for shedding light on the non-perturbative structure of the proton, at low energy, and on the transition from the non-perturbative regime to the perturbative one, that occurs at high energy. Moreover, the possibility to extract Compton form factors and the Generalized Parton Distributions, one of the most promising theoretical tool to determine the total angular momentum contribution of quarks and gluons to nucleon spin, is emphasized.
Inelastic scattering of 72,74Ni off a proton target
NASA Astrophysics Data System (ADS)
Cortés, M. L.; Doornenbal, P.; Obertelli, A.; Pietralla, N.; Werner, V.; Authelet, G.; Baba, H.; Calvet, D.; Château, F.; Corsi, A.; Delbart, A.; Gheller, J.-M.; Gillibert, A.; Isobe, T.; Lapoux, V.; Louchart, C.; Matsushita, M.; Momiyama, S.; Motobayashi, T.; Niikura, M.; Otsu, H.; Péron, C.; Peyaud, A.; Pollacco, E. C.; Roussé, J.-Y.; Sakurai, H.; Santamaria, C.; Sasano, M.; Shiga, Y.; Takeuchi, S.; Taniuchi, R.; Uesaka, T.; Wang, H.; Yoneda, K.; Browne, F.; Chung, L. X.; Dombradi, Zs; Franchoo, S.; Giacoppo, F.; Gottardo, A.; Hadynska-Klek, K.; Korkulu, Z.; Koyama, S.; Kubota, Y.; Lee, J.; Lettmann, M.; Lozeva, R.; Matsui, K.; Miyazaki, T.; Nishimura, S.; Olivier, L.; Ota, S.; Patel, Z.; Sahin, E.; Shand, C. M.; Söderström, P.-A.; Stefan, I.; Steppenbeck, D.; Sumikama, T.; Suzuki, D.; Vajta, Zs; Wu, J.; Xu, Z.
2016-06-01
Inelastic scattering of 72,74Ni off a proton target was performed at RIBF, RIKEN, Japan. The isotopes were produced by the fission of 238U on a thick Beryllium target and were then selected and identified on an event-by-event basis using the BigRIPS separator. Selected isotopes were focused onto the liquid hydrogen target of the MINOS device and gamma rays from the reactions were measured with the DALI2 array. The energy of the ions in the middle of the target was 213 MeV/u. Outgoing particles were identified using the ZeroDegree spectrometer. Here, we report on the current status of the data analysis and preliminary results for the proton inelastic scattering cross sections for both isotopes.
Measurement of the angular distribution of neutron-proton scattering at 10 MeV
Haight, R.C.; Bateman, F.B.; Grimes, S.M.; Brient, C.E.; Massey, T.N.; Wasson, O.A.; Carlson, A.D.; Zhou, H.
1995-12-31
The relative angular distribution of neutrons scattered from protons was measured at an incident neutron energy of 10 MeV at the Ohio University Accelerator Laboratory. An array of 11 detector telescopes at laboratory angles of 0 to 60 degrees was used to detect recoil protons from neutron interactions with a CH{sub 2} (polypropylene) target. Data for 7 of these telescopes were obtained with one set of electronics and are presented here. These data, from 108 to 180 degrees for the center-of-mass scattering angles, have a small slope which agrees better with angular distributions predicted by the Arndt phase shifts than with the ENDF/B-VI angular distribution.
Commissioning a passive-scattering proton therapy nozzle for accurate SOBP delivery
Engelsman, M.; Lu, H.-M.; Herrup, D.; Bussiere, M.; Kooy, H. M.
2009-01-01
Proton radiotherapy centers that currently use passively scattered proton beams do field specific calibrations for a non-negligible fraction of treatment fields, which is time and resource consuming. Our improved understanding of the passive scattering mode of the IBA universal nozzle, especially of the current modulation function, allowed us to re-commission our treatment control system for accurate delivery of SOBPs of any range and modulation, and to predict the output for each of these fields. We moved away from individual field calibrations to a state where continued quality assurance of SOBP field delivery is ensured by limited system-wide measurements that only require one hour per week. This manuscript reports on a protocol for generation of desired SOBPs and prediction of dose output. PMID:19610306
NASA Astrophysics Data System (ADS)
Ruterbories, Daniel
Tokai-to-Kamioka (T2K) is a second generation accelerator neutrino oscillation experiment. T2K uses a high intensity proton beam produced at the Japan Proton Accelerator Research Complex (J-PARC) incident on a carbon target and focused with three magnetic horns to produce a high intensity and nearly pure muon neutrino beam with a peak energy of 600 MeV at a 2.5º axis angle. The muon neutrino beam travels 295 km across Japan to the Super Kamiokande (SK) water Cherenkov detector in the Kamioka mine. The neutrino beam is also sampled by a complex of near detectors 280 m downstream of the carbon target located both on and off the beam axis. These detectors measure the neutrino beam before neutrino oscillations occur to provide input constraints to oscillation searches using SK. The off-axis near detector, ND280, is a composite detector made up of a tracker section and a Pi-Zero detector (POD), all surrounded by an electromagnetic calorimeter. The entire detector is enclosed in a dipole magnet with a field of 0.2 T. The primary purpose of the tracker section is to measure neutrino induced charged current events characterized by the production of muons. The POD is primarily designed to detect electromagnetic showers and to measure interactions on water through the use of a removable water target. In addition to these measurements, the ND280 detector is also used to study the cross sections of neutrino interactions on the various materials in the detectors. Limited knowledge of the cross sections in this neutrino energy regime are an important source of systematic error in neutrino oscillation measurements. This thesis presents a measurement of one neutrino interaction channel in the POD, neutral current elastic scattering (NCE). In this process a neutrino elastically scatters off a proton or neutron in the target nucleus producing a proton or neutron with higher energy. The signature of this process is a single proton track. A particle identification algorithm (PID) was
Multi-jet production rates in deep-inelastic muon-proton scattering
Salgado, C.W. )
1992-02-01
Measurements of forward multi-jet production rates in deep-inelastic muon-proton scattering are presented. Data were taken with a 490 GeV muon beam incident on a hydrogen target. Jets were defined using the JADE jet finding algorithm. The measured rates are presented as function of W, the hadronic center-of-mass energy and the jet resolution parameter, [ital y][sub [ital cut
Toward a QCD analysis of jet rates in deep-inelastic Muon-Proton scattering
Salgado, C.W.; E665 Collaboration
1993-08-01
Measurements of multi-jet production rates in deep-inelastic Muon-Proton scattering at Fermilab-E665 are presented. Jet rates defined by the JADE clustering algorithm are compared to perturbative Quantum chromodynamics (PQCD) and different Monte Carlo model predictions. The applicability of the jet-parton duality hypothesis is studied. We obtain hadronic jet rates which are approximately a factor of two higher than PQCD predictions at the parton level. Possible causes for this discrepancy are discussed.
Enrico Fermi: The First Chain Reactor (with Film) and Pion-Proton Scattering
Martin, Ron
2003-01-08
A twenty minute film will be shown depicting the first nuclear chain reactor at the University of Chicago on December 2, 1942. The film was made of a re-enactment in 1952 and is narrated by Arthur Compton and Enrico Fermi. After the film, Ronald Martin will talk about his experiences on pion-proton scattering with Enrico Fermi at the Chicago synchrocyclotron in the fifties.
Al-Wahish, Amal; Armitage, D.; Hill, B.; Mills, R.; Santodonato, L.; Herwig, K. W.; Al-Binni, U.; Jalarvo, N.; Mandrus, D.
2015-09-15
A design for a sample cell system suitable for high temperature Quasi-Elastic Neutron Scattering (QENS) experiments is presented. The apparatus was developed at the Spallation Neutron Source in Oak Ridge National Lab where it is currently in use. The design provides a special sample cell environment under controlled humid or dry gas flow over a wide range of temperature up to 950 °C. Using such a cell, chemical, dynamical, and physical changes can be studied in situ under various operating conditions. While the cell combined with portable automated gas environment system is especially useful for in situ studies of microscopic dynamics under operational conditions that are similar to those of solid oxide fuel cells, it can additionally be used to study a wide variety of materials, such as high temperature proton conductors. The cell can also be used in many different neutron experiments when a suitable sample holder material is selected. The sample cell system has recently been used to reveal fast dynamic processes in quasi-elastic neutron scattering experiments, which standard probes (such as electrochemical impedance spectroscopy) could not detect. In this work, we outline the design of the sample cell system and present results demonstrating its abilities in high temperature QENS experiments.
Elastic and inelastic neutron scattering from /sup 27/Al at 11, 14, and 17 MeV
Whisnant, C.S.; Dave, J.H.; Gould, C.R.
1984-11-01
Fast neutron scattering cross sections have been measured for /sup 27/Al using a neutron time-of-flight facility. Angular distributions were measured at angles from 20/sup 0/ to 160/sup 0/ in 5/sup 0/ increments, at incident neutron energies of 11, 14, and 17 MeV. Data are presented for elastic scattering and for inelastic scattering to the sum of the 0.84 and 1.01 MeV states, the 2.21 MeV state, and the sum of the 2.73, 2.98, and 3.00 MeV states. After correcting for compound nucleus effects, the elastic scattering cross sections are well reproduced by the spherical optical model using a linear energy dependence in the real well depth. The inelastic data are interpreted with a coupled channels calculation and the excited core model.
NASA Astrophysics Data System (ADS)
Khakoo, Murtadha A.
2011-10-01
The near-threshold scattering of electrons from polyatomic molecules of fundamental interest, e.g. water, primary alcohols and ring molecules e.g. furan, benzene are important in plasma fuel processes, plasmas used in biological processes e.g. in the treatment of skin diseases, astrophysical plasmas, etc. The determination of cross-sections for such molecules has gathered impetus because of the increasing number of applications industrial plasma and biomedical processes and the need to understand and model these complex processes. It is now possible to determine accurate differential cross-sections for electron scattering from these polyatomic molecules. We will present recent normalized, absolute low energy electron scattering differential cross-sections for near-threshold elastic and inelastic scattering from water, primary alcohols, furan and benzene using a well-tested electron spectrometer apparatus. We will also compare our results with those of other experiments and available theoretical models, which show an encouragingly overall improved picture in terms of agreement between the different research groups. Funded by the National Science Foundation Research in an Undergraduate Institution Grant #s 0653452 and 1135203. This work was done collaboratively with Drs. V. Mckoy and C. Winstead, Caltech, USA (National Science Foundation Grant # 0653396 and Office of Basic Energy Sciences, US DOE Grant) and Dr. M. C. A. Lopes, U. Fed. de Juiz de Fora, Minas Gerais, Brazil; Dr. M. H. F. Bettega, U. Fed. do Parana, Curitiba, Brazil Drs. R. F. da Costa and M. A. P. Lima, Universidade Estadual de Campinas UNICAMP and CTBE, Campinas, Brazil (CNPq, FAPESP, FAPEMG, Finep, CENAPAD-SP and CAPES grants). Funded by US-NSF Grant #s 0653452 and 1135203.
NASA Astrophysics Data System (ADS)
Gryniuk, Oleksii; Hagelstein, Franziska; Pascalutsa, Vladimir
2016-08-01
The forward Compton scattering off the proton is determined by substituting the empirical total photoabsorption cross sections into dispersive sum rules. In addition to the spin-independent amplitude evaluated previously [Phys. Rev. D 92, 074031 (2015)], we obtain the spin-dependent amplitude over a broad energy range. The two amplitudes contain all the information about the forward CS process and we hence can reconstruct the observables. The results are compared with predictions of chiral perturbation theory where available. The low-energy expansion of the spin-dependent Compton scattering amplitude yields the Gerasimov-Drell-Hearn (GDH) sum rule and relations for the forward spin polarizabilities (FSPs) of the proton. Our evaluation provides an empirical verification of the GDH sum rule for the proton and yields empirical values of the proton FSPs. For the GDH integral, we obtain 204.5 (21.4 ) μ b , in agreement with the sum rule prediction: 204.784481 (4 ) μ b . For the FSPs, we obtain γ0=-92.9 (10.5 )×10-6 fm4 and γ0¯=48.4 (8.2 )×10-6 fm6, improving on the accuracy of previous evaluations.
The effects of titanium mesh on passive-scattering proton dose
NASA Astrophysics Data System (ADS)
Lin, H.; Ding, X.; Yin, L.; Zhai, H.; Liu, H.; Kassaee, A.; Hill-Kayser, C.; Lustig, R. A.; McDonough, J.; Both, S.
2014-05-01
High-density metallic implants can introduce considerable uncertainties in proton therapy treatment planning. These uncertainties eventually translate into proton range errors, which may cause significant underdosing to the target volume or overdosing to normal tissue beyond the target. This study investigated the dosimetric impact of a 0.6 mm titanium (Ti) mesh implant in passive-scattering proton beam therapy through the study of the depth dose and output in water, and the dose profiles in solid water at various depths. The measurements were performed for a beam with a range of 8.5 cm and a modulation of 7.5 cm. The titanium mesh was placed at a depth of 1 cm below the surface of the phantom for all measurements. A range reduction of 0.5 ± 0.1 mm was observed for a beam perpendicular to the mesh, with no further reductions when the incident angle increased to 60°. We conclude that the dosimetric effect of a 0.6 mm titanium mesh implant is small for a passive scattering proton beam. With proper correction applied to metal artifacts, consistent results were observed in the phantom study in the treatment planning system.
SU-E-T-523: On the Radiobiological Impact of Lateral Scatter in Proton Beams
Heuvel, F Van den; Deruysscher, D
2014-06-01
Introduction: In proton therapy, justified concern has been voiced with respect to an increased efficiency in cell kill at the distal end of the Bragg peak. This coupled with range uncertainty is a counter indication to use the Bragg peak to define the border of a treated volume with a critical organ. An alternative is to use the lateral edge of the proton beam, obtaining more robust plans. We investigate the spectral and biological effects of the lateral scatter . Methods: A general purpose Monte Carlo simulation engine (MCNPX 2.7c) installed on a Scientific Linux cluster, calculated the dose deposition spectrum of protons, knock on electrons and generated neutrons for a proton beam with maximal kinetic energy of 200MeV. Around the beam at different positions in the beam direction the spectrum is calculated in concentric rings of thickness 1cm. The deposited dose is converted to a double strand break map using an analytical expression.based on micro dosimetric calculations using a phenomenological Monte Carlo code (MCDS). A strict version of RBE is defined as the ratio of generation of double strand breaks in the different modalities. To generate the reference a Varian linac was modelled in MCNPX and the generated electron dose deposition spectrum was used . Results: On a pristine point source 200MeV beam the RBE before the Bragg peak was of the order of 1.1, increasing to 1.7 right behind the Bragg peak. When using a physically more realistic beam of 10cm diameter the effect was smaller. Both the lateral dose and RBE increased with increasing beam depth, generating a dose deposition with mixed biological effect. Conclusions: The dose deposition in proton beams need to be carefully examined because the biological effect will be different depending on the treatment geometry. Deeply penetrating proton beams generate more biologically effective lateral scatter.
Qattan, Issam A.
2005-12-01
Due to the inconsistency in the results of the mupGEp/GMp ratio of the proton, as extracted from the Rosenbluth and recoil polarization techniques, high precision measurements of the e-p elastic scattering cross sections were made at Q^{2} = 2.64, 3.20, and 4.10 GeV^{2}. Protons were detected, in contrast to previous measurements where the scattered electrons were detected, which dramatically decreased-dependent systematic uncertainties and corrections. A single spectrometer measured the scattered protons of interest while simultaneous measurements at Q^{2} = 0.5 GeV^{2} were carried out using another spectrometer which served as a luminosity monitor in order to remove any uncertainties due to beam charge and target density fluctuations. The absolute uncertainty in the measured cross sections is ~3% for both spectrometers and with relative uncertainties, random and slope, below 1% for the higher Q^{2} protons, and below 1% random and 6% slope for the monitor spectrometer. The extracted electric and magnetic form factors were determined to 4%-7% for GEp and 1.5% for GMp. The ratio mupGEp/GMp was determined to 4%-7% and showed mupGEp/GMp ~ 1.0. The results of this work are in agreement with the previous Rosenbluth data and inconsistent with high-Q^{2} recoil polarization results, implying a systematic difference between the two techniques.
Khurgin, Jacob B.; Bajaj, Sanyam; Rajan, Siddharth
2015-12-28
Longitudinal optical (LO) phonons in GaN generated in the channel of high electron mobility transistors (HEMT) are shown to undergo nearly elastic scattering via collisions with hot electrons. The net result of these collisions is the diffusion of LO phonons in the Brillouin zone causing reduction of phonon and electron temperatures. This previously unexplored diffusion mechanism explicates how an increase in electron density causes reduction of the apparent lifetime of LO phonons, obtained from the time resolved Raman studies and microwave noise measurements, while the actual decay rate of the LO phonons remains unaffected by the carrier density. Therefore, the saturation velocity in GaN HEMT steadily declines with increased carrier density, in a qualitative agreement with experimental results.
Creation of X-Ray Transparency of Matter by Stimulated Elastic Forward Scattering.
Stöhr, J; Scherz, A
2015-09-01
X-ray absorption by matter has long been described by the famous Beer-Lambert law. Here, we show how this fundamental law needs to be modified for high-intensity coherent x-ray pulses, now available at x-ray free electron lasers, due to the onset of stimulated elastic forward scattering. We present an analytical expression for the modified polarization-dependent Beer-Lambert law for the case of resonant core-to-valence electronic transitions and incident transform limited x-ray pulses. Upon transmission through a solid, the resonant absorption and dichroic contrasts are found to vanish with increasing x-ray intensity, with the stimulation threshold lowered by orders of magnitude through a resonant superradiantlike effect. Our results have broad implications for the study of matter with x-ray lasers. PMID:26382702
Creation of X-Ray Transparency of Matter by Stimulated Elastic Forward Scattering
NASA Astrophysics Data System (ADS)
Stöhr, J.; Scherz, A.
2015-09-01
X-ray absorption by matter has long been described by the famous Beer-Lambert law. Here, we show how this fundamental law needs to be modified for high-intensity coherent x-ray pulses, now available at x-ray free electron lasers, due to the onset of stimulated elastic forward scattering. We present an analytical expression for the modified polarization-dependent Beer-Lambert law for the case of resonant core-to-valence electronic transitions and incident transform limited x-ray pulses. Upon transmission through a solid, the resonant absorption and dichroic contrasts are found to vanish with increasing x-ray intensity, with the stimulation threshold lowered by orders of magnitude through a resonant superradiantlike effect. Our results have broad implications for the study of matter with x-ray lasers.
NASA Astrophysics Data System (ADS)
Khurgin, Jacob B.; Bajaj, Sanyam; Rajan, Siddharth
2015-12-01
Longitudinal optical (LO) phonons in GaN generated in the channel of high electron mobility transistors (HEMT) are shown to undergo nearly elastic scattering via collisions with hot electrons. The net result of these collisions is the diffusion of LO phonons in the Brillouin zone causing reduction of phonon and electron temperatures. This previously unexplored diffusion mechanism explicates how an increase in electron density causes reduction of the apparent lifetime of LO phonons, obtained from the time resolved Raman studies and microwave noise measurements, while the actual decay rate of the LO phonons remains unaffected by the carrier density. Therefore, the saturation velocity in GaN HEMT steadily declines with increased carrier density, in a qualitative agreement with experimental results.
Background Neutron Studies for Coherent Elastic Neutrino-Nucleus Scattering Measurements at the SNS
NASA Astrophysics Data System (ADS)
Markoff, Diane; Coherent Collaboration
2015-10-01
The COHERENT collaboration has proposed to measure coherent, elastic neutrino-nucleus scattering (CE νNS) cross sections on several nuclear targets using neutrinos produced at the Spallation Neutron Source (SNS) located at the Oak Ridge National Laboratory. The largest background of concern arises from beam-induced, fast neutrons that can mimic a nuclear recoil signal event in the detector. Multiple technologies of neutron detection have been employed at prospective experiment sites at the SNS. Analysis of these data have produced a consistent picture of the backgrounds expected for a CE νNS measurement. These background studies show that at suitable locations, the fast neutrons of concern arrive mainly in the prompt 1.3 μs window and the neutrons in the delayed window are primarily of lower energies that are relatively easier to shield.
Quasi elastic and inelastic neutron scattering study of vitamin C aqueous solutions
NASA Astrophysics Data System (ADS)
Migliardo, F.; Branca, C.; Magazù, S.; Migliardo, P.; Coppolino, S.; Villari, A.; Micali, N.
2002-02-01
In this paper, new results obtained by quasi elastic and inelastic neutron scattering experiments performed on vitamin C ( L-ascorbic acid)/H 2O mixtures are reported. The data analysis of the QENS measurements, by a separation of the diffusive dynamics of hydrated L-ascorbic acid from that of water, furnishes quantitative evidences of a random jump diffusion motion of vitamin C and shows that the water dynamics is strongly affected by the presence of L-ascorbic acid. Concerning the INS experiment, we are able, through the behaviour of neutron spectra across the glass transition temperature ( T g≈233 K for the vitamin C/water system), to collocate the investigated system in the Angell “strong-fragile” scheme.
{ital S}-matrix analysis of heavy-ion elastic scattering
Chiste, V.; Lichtenthaeler, R.; Villari, A.C.; Gomes, L.C.
1996-08-01
A procedure to minimize {chi}{sup 2} is described which explores the fact that the {chi}{sup 2} distribution is of the fourth degree in the {ital S}-matrix elements. The fact that all three roots of the scale parameter for the minimum of {chi}{sup 2} in its gradient direction are algebraically determined gives the present procedure some global features that previous methods did not contemplate. The automatic search procedure also preserves the unitary bound constraint of the {ital S}-matrix at every step. When the search in the gradient direction slows down, the procedure reverts to the traditional quadratic approximation with zero-order regularization. The method is applied to the elastic scattering of the {sup 12}C+{sup 16}O reaction near the Coulomb barrier. {copyright} {ital 1996 The American Physical Society.}
Elastic scattering of 96 MeV neutrons from iron, yttrium, and lead
Oehrn, A.; Blomgren, J.; Andersson, P.
2008-02-15
Data on elastic scattering of 96 MeV neutrons from {sup 56}Fe, {sup 89}Y, and {sup 208}Pb in the angular interval 10-70 deg. are reported. The previously published data on {sup 208}Pb have been extended, as a new method has been developed to obtain more information from data, namely to increase the number of angular bins at the most forward angles. A study of the deviation of the zero-degree cross section from Wick's limit has been performed. It was shown that the data on {sup 208}Pb are in agreement with Wick's limit while those on the lighter nuclei overshoot the limit significantly. The results are compared with modern optical model predictions, based on phenomenology and microscopic nuclear theory. The data on {sup 56}Fe, {sup 89}Y, and {sup 208}Pb are in general in good agreement with the model predictions.
NASA Astrophysics Data System (ADS)
Hagino, K.
2009-05-01
We invert experimental data for heavy-ion fusion cross sections at energies well below the Coulomb barrier in order to directly determine the internucleus potential between the colliding nuclei. In contrast to the previous applications of the inversion formula, we explicitly take into account the effect of channel couplings on fusion reactions, by assuming that fusion cross sections at deep subbarrier energies are governed by the lowest barrier in the barrier distribution. The surface region of the internuclear potential is determined from quasi-elastic scattering at deep subbarrier energies, while the inner part is determined with the WKB formula. We apply this procedure to the 16O+144Sm and 16O+208Pb reactions, and find that the inverted internucleus potential are much thicker than phenomenological potentials.
Low-energy electron elastic scattering cross sections for excited Au and Pt atoms
NASA Astrophysics Data System (ADS)
Felfli, Zineb; Eure, Amanda R.; Msezane, Alfred Z.; Sokolovski, Dmitri
2010-05-01
Electron elastic total cross sections (TCSs) and differential cross sections (DCSs) in both impact energy and scattering angle for the excited Au and Pt atoms are calculated in the electron impact energy range 0 ⩽ E ⩽ 4.0 eV. The cross sections are found to be characterized by very sharp long-lived resonances whose positions are identified with the binding energies of the excited anions formed during the collisions. The recent novel Regge-pole methodology wherein is embedded through the Mulholland formula the electron-electron correlations is used together with a Thomas-Fermi type potential incorporating the crucial core-polarization interaction for the calculations of the TCSs. The DCSs are evaluated using a partial wave expansion. The Ramsauer-Townsend minima, the shape resonances and the binding energies of the excited Au - and Pt - anions are extracted from the cross sections, while the critical minima are determined from the DCSs.
Hydrogen species motion in piezoelectrics: A quasi-elastic neutron scattering study
NASA Astrophysics Data System (ADS)
Alvine, K. J.; Tyagi, M.; Brown, C. M.; Udovic, T. J.; Jenkins, T.; Pitman, S. G.
2012-03-01
Hydrogen is known to damage or degrade piezoelectric materials, at low pressure for ferroelectric random access memory applications, and at high pressure for hydrogen-powered vehicle applications. The piezoelectric degradation is in part governed by the motion of hydrogen species within the piezoelectric materials. We present here quasi-elastic neutron scattering (QENS) measurements of the local hydrogen species motion within lead zirconate titanate (PZT) and barium titanate (BTO) on samples charged by exposure to high-pressure gaseous hydrogen (≈17 MPa). Neutron vibrational spectroscopy (NVS) studies of the hydrogen-enhanced vibrational modes are presented as well. Results are discussed in the context of theoretically predicted interstitial hydrogen lattice sites and compared to comparable bulk diffusion studies of hydrogen diffusion in lead zirconate titanate.
Cross sections for elastic electron scattering by tetramethylsilane in the intermediate-energy range
Sugohara, R. T.; Lee, M.-T.; Iga, I.; Souza, G. L. C. de; Homem, M. G. P.
2011-12-15
Organosilicon compounds are of current interest due to the numerous applications of these species in industries. Some of these applications require the knowledge of electron collision cross sections, which are scarce for such compounds. In this work, we report absolute values of differential, integral, and momentum-transfer cross sections for elastic electron scattering by tetramethylsilane (TMS) measured in the 100-1000 eV energy range. The relative-flow technique is used to normalize our data. In addition, the independent-atom-model (IAM) and the additivity rule (AR), widely used to model electron collisions with light hydrocarbons, are also applied for e{sup -}-TMS interaction. The comparison of our measured results of cross sections and the calculated data shows good agreement, particularly near the higher-end of incident energies.
Gakh, G. I.; Konchatnij, M. I. Merenkov, N. P.
2012-08-15
The model-independent QED radiative corrections to polarization observables in elastic scattering of unpolarized and longitudinally polarized electron beams by a deuteron target are calculated in leptonic variables. The experimental setup when the deuteron target is arbitrarily polarized is considered and the procedure for applying the derived results to the vector or tensor polarization of the recoil deuteron is discussed. The calculation is based on taking all essential Feynman diagrams into account, which results in the form of the Drell-Yan representation for the cross section, and the use of the covariant parameterization of the deuteron polarization state. Numerical estimates of the radiative corrections are given in the case where event selection allows undetected particles (photons and electron-positron pairs) and the restriction on the lost invariant mass is used.
Quasi-Elastic Light Scattering by Diffusional Fluctuations in RNase Solutions
Rimai, L.; Hickmott, J. T.; Cole, T.; Carew, E. B.
1970-01-01
Using measurements of quasi-elastic light scattering spectra, we have investigated diffusional fluctuations of RNase. The diffusion coefficient for individual protein molecules, together with the corresponding calculated effective molecular radius Reff, were determined. Between room temperature and the point of irreversible denaturation at 63.5°C, Reff increased from 20-250 A. This is comparable to the plateau in Reff of 300 A reached after about 200 min following chemical denaturation in 10 M urea. The measurements indicated the presence of a large size component even in the freshly prepared and chromatographically purified solutions. From the diffusion constants deduced for this large component we obtained effective sizes from 1000-5000 A. Concentration and temperature dependent measurements exclude the possibility that these large particles are impurities and indicate that they are the result of aggregations of RNase molecules. PMID:5409774
Curve crossing for low-energy elastic scattering of He/+/ by Ne.
NASA Technical Reports Server (NTRS)
Bobbio, S. M.; Doverspike, L. D.; Champion, R. L.
1973-01-01
The perturbation seen in the experimental differential elastic-scattering cross section for the 40-eV He/+/ + Ne system has been attributed to a single crossing of two intermolecular potential-energy curves. A new theoretical treatment of the curve-crossing problem, namely, that of Delos and Thorson, is employed to obtain the crossing probabilities and phases associated with the crossing. These are determined by utilizing ab initio potentials involved in the crossing and are further used in a partial-wave calculation of the cross section, which is compared with our experiment. The origin of the oscillatory structure observed in the differential cross section is discussed in semiclassical terms by defining the problem in terms of two pseudo-deflection-functions. A rainbow effect is shown to be related to a particular feature (a maximum rather than a minimum) of these deflection functions.
Kamyshkov, Yuri; Tithof, Jeffrey; Vysotsky, Mikhail
2008-12-01
We found that spin-one new light particle exchanges are strongly bounded by high-energy and small momentum transfer np elastic scattering data; the analogous bound for a scalar particle is considerably weaker, while for a pseudoscalar particle no bounds can be set. These bounds are compared with the bounds extracted from low-energy n-Pb scattering experiments and from the bounds of {pi}{sup 0} and K{sup +} meson decays.
Aoun, Bachir; Pellegrini, Eric; Trapp, Marcus; Natali, Francesca; Cantù, Laura; Brocca, Paola; Gerelli, Yuri; Demé, Bruno; Marek Koza, Michael; Johnson, Mark; Peters, Judith
2016-04-01
Neutron scattering techniques have been employed to investigate 1,2-dimyristoyl-sn -glycero-3-phosphocholine (DMPC) membranes in the form of multilamellar vesicles (MLVs) and deposited, stacked multilamellar-bilayers (MLBs), covering transitions from the gel to the liquid phase. Neutron diffraction was used to characterise the samples in terms of transition temperatures, whereas elastic incoherent neutron scattering (EINS) demonstrates that the dynamics on the sub-macromolecular length-scale and pico- to nano-second time-scale are correlated with the structural transitions through a discontinuity in the observed elastic intensities and the derived mean square displacements. Molecular dynamics simulations have been performed in parallel focussing on the length-, time- and temperature-scales of the neutron experiments. They correctly reproduce the structural features of the main gel-liquid phase transition. Particular emphasis is placed on the dynamical amplitudes derived from experiment and simulations. Two methods are used to analyse the experimental data and mean square displacements. They agree within a factor of 2 irrespective of the probed time-scale, i.e. the instrument utilized. Mean square displacements computed from simulations show a comparable level of agreement with the experimental values, albeit, the best match with the two methods varies for the two instruments. Consequently, experiments and simulations together give a consistent picture of the structural and dynamical aspects of the main lipid transition and provide a basis for future, theoretical modelling of dynamics and phase behaviour in membranes. The need for more detailed analytical models is pointed out by the remaining variation of the dynamical amplitudes derived in two different ways from experiments on the one hand and simulations on the other. PMID:27112937
Ambiguities in the elastic scattering of 8 MeV neutrons from adjacent nuclei
Smith, A.B.; Lawson, R.D.; Guenther, P.T.
1989-10-01
Ratios of the cross sections for elastic scattering of 8 MeV neutrons from adjacent nuclei are measured over the angular range {approx}20{degree} {minus} 160{degree} for the target pairs {sup 51}V/Cr, {sup 59}Co/{sup 58}Ni, Cu/Zn, {sup 89}Y/{sup 93}Nb, {sup 89}Y/Zr, {sup 93}Nb/Zr, In/Cd and {sup 209}Bi/Pb. The observed ratios vary from unity by as much as a factor of {approx}2 at some angles for the lighter target pairs. Approximately half the measured ratios are reasonably explained by a simple spherical optical model, including size and isospin contributions. In all cases, the geometry of the real optical--model potential is essentially the same for neighboring nuclei, and the real--potential strengths are consistent with the Lane model. In contrast, it is found that the imaginary potential may be quite different for adjacent nuclei, and the nature of this difference is examined. It is shown that the spin--spin interaction has a negligible effect on the calculation of the elastic--scattering ratios, but that channel coupling, leading to a large reorientation of the target ground state, can be a consideration, particularly in the {sup 59}Co/{sup 58}Ni case. In the A {approx} 50--60 region the calculated ratios are sensitive to spin--orbit effects, but the exact nature of this interaction must await more definitive polarization measurements. The measured and calculated results suggest that the concept of a conventional global'' or even regional'' optical potential provides no more than a qualitative representation of the physical reality for a number of cases. 48 refs., 14 figs., 3 tabs.
Aoun, Bachir; Pellegrini, Eric; Trapp, Marcus; Natali, Francesca; Cantù, Laura; Brocca, Paola; Gerelli, Yuri; Demé, Bruno; Marek Koza, Michael; Johnson, Mark; Peters, Judith
2016-04-01
Neutron scattering techniques have been employed to investigate 1,2-dimyristoyl-sn -glycero-3-phosphocholine (DMPC) membranes in the form of multilamellar vesicles (MLVs) and deposited, stacked multilamellar-bilayers (MLBs), covering transitions from the gel to the liquid phase. Neutron diffraction was used to characterise the samples in terms of transition temperatures, whereas elastic incoherent neutron scattering (EINS) demonstrates that the dynamics on the sub-macromolecular length-scale and pico- to nano-second time-scale are correlated with the structural transitions through a discontinuity in the observed elastic intensities and the derived mean square displacements. Molecular dynamics simulations have been performed in parallel focussing on the length-, time- and temperature-scales of the neutron experiments. They correctly reproduce the structural features of the main gel-liquid phase transition. Particular emphasis is placed on the dynamical amplitudes derived from experiment and simulations. Two methods are used to analyse the experimental data and mean square displacements. They agree within a factor of 2 irrespective of the probed time-scale, i.e. the instrument utilized. Mean square displacements computed from simulations show a comparable level of agreement with the experimental values, albeit, the best match with the two methods varies for the two instruments. Consequently, experiments and simulations together give a consistent picture of the structural and dynamical aspects of the main lipid transition and provide a basis for future, theoretical modelling of dynamics and phase behaviour in membranes. The need for more detailed analytical models is pointed out by the remaining variation of the dynamical amplitudes derived in two different ways from experiments on the one hand and simulations on the other.
Low-energy electron elastic scattering from Os atom: New electron affinity
NASA Astrophysics Data System (ADS)
Felfli, Z.; Kiros, F.; Msezane, A. Z.
2013-05-01
Bilodeau and Haugan measured the binding energies (BEs) of the ground state and the excited state of the Os- ion to be 1.07780(12) eV and 0.553(3) eV, respectively. These values are consistent with those calculated in. Here our investigation, using the recent complex angular momentum methodology wherein is embedded the crucial electron-electron correlations and the vital core polarization interaction, has found that the near threshold electron-Os elastic scattering total cross section (TCS) is characterized by three stable bound states of the Os- ion formed as resonances during the slow electron collision, with BEs of 1.910 eV, 1.230 eV and 0.224 eV. The new extracted electron affinity (EA) value from the TCS of 1.910 eV for the Os atom is significantly different from that measured in. Our calculated elastic differential cross sections (DCSs) also yield the relevant BEs for the ground and the two excited states of the Os- ion. The complex characteristic resonance structure in the TCS for the Os atom is ideal for catalysis, but makes it difficult to execute the Wigner threshold law in describing the threshold detachment behavior of complex atoms and extracting the reliable attendant EAs. Supported by U.S. DOE, AFOSR and CAU CFNM, NSF-CREST Program.
NASA Astrophysics Data System (ADS)
Magazó, Salvatore; Migliardo, Federica; Benedetto, Antonio
2012-10-01
Recently [S. Magazù et al., Rev. Sci. Instrum. 82, 105115 (2011), 10.1063/1.3641870] we have proposed a new method for characterizing, by neutron scattering, the dynamical properties of complex material systems, such as, the ones of interest in the biophysical field. This approach called Resolution Elastic Neutron Scattering, in short RENS, is based on the detection of the elastically scattered neutron intensity as a function of the instrumental energy resolution. By experimental, theoretical, and numerical findings, we have pointed out that an inflection point occurs in the elastic intensity when the system relaxation time approaches the instrumental energy resolution time. This approach, differently from quasi-elastic neutron scattering (QENS), gives the chance to evaluate the system relaxation times without using pre-defined models that can be wrong and/or misleading. Here, we reply to a Comment on the above-mentioned main paper in which Wuttke proposes a different approach to evaluate the above-mentioned inflection point; on this regard, it should be noticed that the existence of the inflection point, which is the main topic of our work, is not questioned and that the approach proposed by Wuttke in the Comment, although valid for a class of dynamical processes, is not applicable when different and distinct processes occur simultaneously at different time scale.
Rahbar, A.A.
1982-09-01
A specific set of spin dependent parameters for elastic scattering of polarized protons from an unpolarized deuterium target have been measured over the angular range of 15/sup 0/ and 65/sup 0/ in the Laboratory system. The experiment was performed at the Los Alamos Meson Physics Facility (LAMPF) using a polarized proton beam of 0.5 and 0.8 GeV incident kinetic energy. A carbon analyzer was used to measure the scattered proton polarization. This comprises the first set of measurements in the intermediate energy range. Of particular interest, the analyzing power, (A/sub y/), has been measured for the pd elastic scattering reaction at both energies. A test of Time-Reversal Invariance (TRI) has been made for this reaction. This was accomplished by comparing the polarization (P) with the analyzing power A/sub y/ together with the depolarization parameter, (D), which was measured in this experiment. No evidence of time-reversal violation was found for this reaction in the region of non-zero spin flip probability. The measurements also furnished very useful and selective information on the p-d collision matrix, as well as the double-spin-flip nucleon-nucleon amplitudes.
NASA Astrophysics Data System (ADS)
Signorini, C.; Mazzocco, M.; Molini, P.; Pierroutsakou, D.; Boiano, C.; Manea, C.; Strano, E.; Torresi, D.; Di Meo, P.; Nicoletto, M.; Boiano, A.; Glodariu, T.; Grebosz, J.; Guglielmetti, A.; La Commara, M.; Parascandolo, C.; Parascandolo, L.; Sandoli, M.; Soramel, F.; Stroe, L.; Toniolo, N.; Veronese, F.
2013-03-01
The quasi elastic scattering of a 17O projectile from a 58Ni target has been studied at beam energies ranging from 42.5 to 55.0 MeV in 2.5 MeV steps. The total reaction cross sections were derived from the measured angular distributions by using an optical model fit within the coupled-channel code FRESCO. These cross sections are very similar to those measured for 17F (loosely bound by 0.6 MeV), mirror nucleus of 17O (tightly bound by 4.14 MeV). This outcome points out that, in this energy range, the small binding energy of the 17F valence proton has negligible influence onto the reactivity of such a loosely bound projectile, contrary to simple expectations, and to what observed for other loosely bound nuclei. The reaction dynamics seems to be influenced mainly by the Coulomb interaction which is similar for both mirror projectiles.
Schiró, Giorgio; Caronna, Chiara; Natali, Francesca; Cupane, Antonio
2010-09-21
Two main onsets of anharmonicity are present in protein dynamics. Neutron scattering on protein hydrated powders revealed a first onset at about 150 K and a second one at about 230 K (the so called dynamical transition). In order to assess the molecular origin of protein anharmonicity, we study different homomeric polypeptides by incoherent elastic neutron scattering, thus disentangling the contribution of different molecular groups in proteins. We show that methyl group rotations are the main contributors to the low temperature onset. Concerning the dynamical transition, we show that it also occurs in absence of side chains; however, the presence and mobility of side chains substantially increases the fluctuations amplitude without influencing the transition temperature. We also investigate the role of hydration on the anharmonic contributions. Our study shows that methyl group rotations are unaffected by hydration and confirms that the dynamical transition is suppressed in dry samples. In hydrated samples, while the pure backbone contribution does not depend on the hydration h at h > or = 0.2, in the presence of side chains the anharmonic fluctuations involved in the dynamical transition are enhanced by increasing the water content.
Scanning elastic scattering spectroscopy detects metastatic breast cancer in sentinel lymph nodes.
Austwick, Martin R; Clark, Benjamin; Mosse, Charles A; Johnson, Kristie; Chicken, D Wayne; Somasundaram, Santosh K; Calabro, Katherine W; Zhu, Ying; Falzon, Mary; Kocjan, Gabrijela; Fearn, Tom; Bown, Stephen G; Bigio, Irving J; Keshtgar, Mohammed R S
2010-01-01
A novel method for rapidly detecting metastatic breast cancer within excised sentinel lymph node(s) of the axilla is presented. Elastic scattering spectroscopy (ESS) is a point-contact technique that collects broadband optical spectra sensitive to absorption and scattering within the tissue. A statistical discrimination algorithm was generated from a training set of nearly 3000 clinical spectra and used to test clinical spectra collected from an independent set of nodes. Freshly excised nodes were bivalved and mounted under a fiber-optic plate. Stepper motors raster-scanned a fiber-optic probe over the plate to interrogate the node's cut surface, creating a 20x20 grid of spectra. These spectra were analyzed to create a map of cancer risk across the node surface. Rules were developed to convert these maps to a prediction for the presence of cancer in the node. Using these analyses, a leave-one-out cross-validation to optimize discrimination parameters on 128 scanned nodes gave a sensitivity of 69% for detection of clinically relevant metastases (71% for macrometastases) and a specificity of 96%, comparable to literature results for touch imprint cytology, a standard technique for intraoperative diagnosis. ESS has the advantage of not requiring a pathologist to review the tissue sample. PMID:20799832
A quasi-elastic light scattering study of smooth muscle myosin in the presence of ATP.
Wu, X; Blank, P S; Carlson, F D
1992-01-01
We have investigated the hydrodynamic properties of turkey gizzard smooth muscle myosin in solution using quasi-elastic light scattering (QELS). The effects of ionic strength (0.05-0.5 M KCl) and light chain phosphorylation on the conformational transition of myosin were examined in the presence of ATP at 20 degrees C. Cumulant analysis and light scattering models were used to describe the myosin system in solution. A nonlinear least squares fitting procedure was used to determine the model that best fits the data. The conformational transition of the myosin monomer from a folded form to an extended form was clearly demonstrated in a salt concentration range of 0.15-0.3 M KCl. Light chain phosphorylation regulates the transition and promotes unfolding of the myosin. These results agree with the findings obtained using sedimentation velocity and electron microscopy (Onishi and Wakabayashi, 1982; Trybus et al., 1982; Trybus and Lowey, 1984). In addition, we present evidence for polymeric myosin coexisting with the two monomeric myosin species over a salt concentration range from 0.05 to 0.5 M KCl. The size of the polymeric myosin varied with salt concentration. This observation supports the hypothesis that, in solution, a dynamic equilibrium exists between the two conformations of myosin monomer and filaments. PMID:1420864
Polarization observables in. pi. d-italic-arrow-right elastic scattering: Amplitude analysis
Garcilazo, H.; Boschitz, E.T.; Gyles, W.; List, W.; Ottermann, C.R.; Tacik, R.; Wessler, M.
1989-03-01
Using the new experimental data on iT/sub 11/, T/sub 20/, tau/sub 21/, and tau/sub 22/, presented in the first two parts of this work, along with existing differential cross section data, a helicity amplitude reconstruction of ..pi..d elastic scattering has been performed at T/sub ..pi../ = 256 and 294 MeV. Model-independent information has been obtained for the amplitudes /vert bar/B/vert bar/, (/vert bar/A/vert bar//sup 2/+/vert bar/C/vert bar//sup 2/)/sup 1/2/, /vert bar/D/vert bar/, and the phase phi/sub D/. Taking two relations from a theoretical model in addition to the five existing observables, the seven real components of the ..pi..d helicity amplitudes have been determined. These amplitudes have then been used to calculate spin-transfer observables and the partial-wave components of the scattering amplitude.
Spin correlation parameter C{sub yy} of p+{sup 3}He elastic backward scattering
Shimizu, Y.; Hatanaka, K.; Tameshige, Y.; Adachi, T.; Fujita, K.; Matsubara, H.; Okamura, H.; Tamii, A.; Kobushkin, A. P.; Kawabata, T.; Sasamoto, Y.; Uesaka, T.; Suda, K.; Itoh, K.; Sakemi, Y.; Wakui, T.; Uchida, M.; Kudoh, T.; Sagara, K.; Wakasa, T.
2007-10-15
We measured the differential cross section and the spin correlation parameter C{sub yy} of the p-vector+{sup 3}He-vector elastic backward scattering at 200, 300, and 400 MeV at {theta}=180 deg. in the center-of-mass frame to study the mechanism of the reaction and to examine the validity of the {sup 3}He wave functions based on two different realistic two-body forces. This is the first measurement of the spin correlation parameter C{sub yy} of the p-vector+{sup 3}He-vector EBS at intermediate energies. The experimental results were compared with few-body calculations, including three reaction mechanisms: two-nucleon-pair exchange, pion exchange, and direct pp scattering. It was found that few-body calculations describe the differential cross-section data reasonably well. The spin correlation parameter C{sub yy} shows clear evidence for the two-nucleon-pair exchange processes in the reaction, demonstrating that the spin observables are helpful for deeper understanding of the reaction mechanism.
Elastic alpha scattering experiments and the alpha-nucleus optical potential at low energies
Mohr, P.; Kiss, G.G.; Fülöp, Zs.; Galaviz, D.; Gyürky, Gy.; Somorjai, E.
2013-11-15
High precision angular distribution data of (α,α) elastic scattering are presented for the nuclei {sup 89}Y, {sup 92}Mo, {sup 106,110,116}Cd, {sup 112,124}Sn, and {sup 144}Sm at energies around the Coulomb barrier. Such data with small experimental uncertainties over the full angular range (20–170°) are the indispensable prerequisite for the extraction of local optical potentials and for the determination of the total reaction cross section σ{sub reac}. A systematic fitting procedure was applied to the experimental scattering data presented to obtain comprehensive local potential parameter sets that are composed of a real folding potential and an imaginary potential of Woods–Saxon surface type. The potential parameters obtained were used in turn to construct a new systematic α-nucleus potential with very few parameters. Although this new potential cannot reproduce the angular distributions with the same small deviations as the local potential, the new potential is able to predict the total reaction cross sections for all cases under study.
Flow Visualization by Elastic Light Scattering in the Boundary Layer of a Supersonic Flow
NASA Technical Reports Server (NTRS)
Herring, G. C.; Hillard, Mervin E., Jr.
2000-01-01
We demonstrate instantaneous flow visualization of the boundary layer region of a Mach 2.5 supersonic flow over a flat plate that is interacting with an impinging shock wave. Tests were performed in the Unitary Plan Wind Tunnel (UPWT) at NASA Langley Research Center. The technique is elastic light scattering using 10-nsec laser pulses at 532 nm. We emphasize that no seed material of any kind, including water (H2O), is purposely added to the flow. The scattered light comes from a residual impurity that normally exists in the flow medium after the air drying process. Thus, the technique described here differs from the traditional vapor-screen method, which is typically accomplished by the addition of extra H2O vapor to the airflow. The flow is visualized with a series of thin two-dimensional light sheets (oriented perpendicular to the streamwise direction) that are located at several positions downstream of the leading edge of the model. This geometry allows the direct observation of the unsteady flow structure in the spanwise dimension of the model and also allows the indirect observation of the boundary layer growth in the streamwise dimension.
Influence of gramicidin on the dynamics of DMPC studied by incoherent elastic neutron scattering
NASA Astrophysics Data System (ADS)
Wanderlingh, U.; D'Angelo, G.; Conti Nibali, V.; Gonzalez, M.; Crupi, C.; Mondelli, C.
2008-03-01
By using the fixed energy window method in incoherent elastic neutron scattering, molecular motions in the 150 ps timescale in highly oriented multilayers of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) membranes in excess of water (D2O) have been studied as a function of temperature, in the range from 27 to 325 K. The same system in partially deuterated form and with the addition of a pore-forming peptide (gramicidin) has also been investigated. By proper orientation of the membrane plane with respect to the scattering wavevector Q, information on in plane and out of plane motions of lipid membranes have been derived. Two relevant dynamical transitions were observed at T = 297 K and at T = 270 K. The former is related to the structural main transition from gel to liquid phase of the phospholipid bilayer, while the latter is related to a transition of the aqueous solvent. The inclusion of gramicidin shifts the main transition down to 294 K and the second transition up to 276 K. In both cases the observed dynamical transitions show an enhanced mobility in the direction normal to the membrane plane.
Statistical model for the prediction of elastic wave scattering from finite complicated shells
NASA Astrophysics Data System (ADS)
He, Hua
This thesis develops a simple statistical model to estimate bistatic elastic scattering from finite complicated shells in the mid-frequency range, 3 < ka/ < 10. The model has three parts: (1) sound power injection into the shell; (2) coupling among the elastic waves in the shell and wave power equipartition (3) sound radiation from the shell. Within 30o of beam aspect, sound power injection into the shell is mainly caused by acoustic trace matching, and is estimated by using an infinitely long shell model. Once trace matched, the compressional and shear waves can couple to each other and to the subsonic flexural waves at shell discontinuities such as bulkheads and endcaps. Under extensive wave conversion, wave power, defined as energy density multiplied by axial group speed, is hypothesized to be equipartitioned among the elastic wave types. Numerical calculations are conducted and the results show that the wave power equipartition hypothesis is plausible for a finite endcapped shell with four heavy deep rings. Using the wave power equipartition hypothesis, the shell motion is then converted to sound pressure in the surrounding fluid using Green's theorem. The sound radiation is further extended to the time domain, using random phase realizations and a decay rate model, which considers various dissipation mechanisms in the shells. The predicted target strength is compared with measured data for the ringed shell and the internalled shell, with the internal structures resiliently mounted to the rings. In terms of the mean target strength over the frequency region 3 < ka/ < 10 and the observation region within 30o of beam aspect, the prediction differs from the measured data by less than 2.5 dB for the second and third roundtrip of the trace matched wave in the shells, as well as for a time integrated case. The ring influence on elastic wave speeds is also studied. Inclusion of the influence in the model does not generally yield a better agreement with the
Range verification of passively scattered proton beams using prompt gamma-ray detection.
Verburg, Joost M; Testa, Mauro; Seco, Joao
2015-02-01
We performed an experimental study to verify the range of passively scattered proton beams by detecting prompt gamma-rays emitted from proton-nuclear interactions. A method is proposed using a single scintillation detector positioned near the distal end of the irradiated target. Lead shielding was used to attenuate gamma-rays emitted along most of the entrance path of the beam. By synchronizing the prompt gamma-ray detector to the rotation of the range modulation wheel, the relation between the gamma emission from the distal part of the target and the range of the incident proton beam was determined. In experiments with a water phantom and an anthropomorphic head phantom, this relation was found to be sensitive to range shifts that were introduced. The wide opening angle of the detector enabled a sufficient signal-to-background ratio to be achieved in the presence of neutron-induced background from the scattering and collimating devices. Uniform range shifts were detected with a standard deviation of 0.1 mm to 0.2 mm at a dose level of 30 cGy to 50 cGy (RBE). The detectable magnitude of a range shift limited to a part of the treatment field area was approximately proportional to the ratio between the field area and the area affected by the range shift. We conclude that it is feasible to detect changes in the range of passively scattered proton beams using a relatively simple prompt gamma-ray detection system. The method can be employed for in vivo verification of the consistency of the delivered range in fractionated treatments.
NASA Technical Reports Server (NTRS)
Register, D. F.; Trajmar, S.; Srivastava, S. K.
1980-01-01
Absolute differential, integral, and momentum-transfer cross sections for electrons elastically scattered from helium are reported for the impact energy range of 5 to 200 eV. Angular distributions for elastically scattered electrons are measured in a crossed-beam geometry using a collimated, differentially pumped atomic-beam source which requires no effective-path-length correction. Below the first inelastic threshold the angular distributions were placed on an absolute scale by use of a phase-shift analysis. Above this threshold, the angular distributions from 10 to 140 deg were fitted using the phase-shift technique, and the resulting integral cross sections were normalized to a semiempirically derived integral elastic cross section. Depending on the impact energy, the data are estimated to be accurate to within 5 to 9%.
Exclusive measurements of quasi-free proton scattering reactions in inverse and complete kinematics
NASA Astrophysics Data System (ADS)
Panin, V.; Taylor, J. T.; Paschalis, S.; Wamers, F.; Aksyutina, Y.; Alvarez-Pol, H.; Aumann, T.; Bertulani, C. A.; Boretzky, K.; Caesar, C.; Chartier, M.; Chulkov, L. V.; Cortina-Gil, D.; Enders, J.; Ershova, O.; Geissel, H.; Gernhäuser, R.; Heil, M.; Johansson, H. T.; Jonson, B.; Kelić-Heil, A.; Langer, C.; Le Bleis, T.; Lemmon, R.; Nilsson, T.; Petri, M.; Plag, R.; Reifarth, R.; Rossi, D.; Scheit, H.; Simon, H.; Weick, H.; Wimmer, C.
2016-02-01
Quasi-free scattering reactions of the type (p , 2 p) were measured for the first time exclusively in complete and inverse kinematics, using a 12C beam at an energy of ˜ 400 MeV /u as a benchmark. This new technique has been developed to study the single-particle structure of exotic nuclei in experiments with radioactive-ion beams. The outgoing pair of protons and the fragments were measured simultaneously, enabling an unambiguous identification of the reaction channels and a redundant measurement of the kinematic observables. Both valence and deeply-bound nucleon orbits are probed, including those leading to unbound states of the daughter nucleus. Exclusive (p , 2 p) cross sections of 15.8(18) mb, 1.9(2) mb and 1.5(2) mb to the low-lying 0p-hole states overlapping with the ground state (3 /2-) and with the bound excited states of 11B at 2.125 MeV (1 /2-) and 5.02 MeV (3 /2-), respectively, were determined via γ-ray spectroscopy. Particle-unstable deep-hole states, corresponding to proton removal from the 0s-orbital, were studied via the invariant-mass technique. Cross sections and momentum distributions were extracted and compared to theoretical calculations employing the eikonal formalism. The obtained results are in a good agreement with this theory and with direct-kinematics experiments. The dependence of the proton-proton scattering kinematics on the internal momentum of the struck proton and on its separation energy was investigated for the first time in inverse kinematics employing a large-acceptance measurement.
NASA Astrophysics Data System (ADS)
Gusev, V. V.; Guseva, N. P.; Tatarintsev, S. N.
1995-01-01
This paper describes the investigation of incorporation processes of the plague lipopolysaccharide (LPS) into artificial phospholipid vesicles (PLV) on the basis of elastic laser radiation scattering. For this purpose, the angular light scattering dependencies of PLV suspensions, containing various LPS concentrations (0 - 5 mg/ml), were measured using the polarization nephelometer. The design of the polarization nephelometer and the measurement technique are described in detail. Measuring results are compared with electron microscopy data. The most pronounced variation as a result of LPS incorporation into PLV appeared to be the light scattering integral intensity (LSII) at angles exceeding 100. It is shown that the LPS adding into the PLV suspension causes the LSII to increase by a factor 2 - 6 for a LPS concentration range from 0.5 to 5 mg/ml as compared with `empty' PLV. Proceeding from the electron microscopy data it was found that the LSII increase, in general case, is conditioned by variation of the PLV membrane refraction index and formation of PLV aggregates. It was shown that the LSII measurement for the PLV suspension containing LPS can be used as a qualitative express analysis for the LPS incorporation into PLV as well as procedure for determination of the aggregate formation stage from PLV. The LPS of the plague, which as determinants being common for various gram-negative bacteria, is of great interest from the viewpoint of creating preparations for prophylactic measures against the endotoxin infections. However, the LPS toxicity due to the lipid A presence is a disadvantage of this weak antigen. Incorporation of the LPS int bilayer phospholipid membranes leads to its lower toxicity and higher immunization ability. The immunization ability and toxicity of the LPS complexes with bilayer membranes depend essentially on the LPS quantity sorbed in the membrane, as well as on the shapes and sizes of aggregates formed by the LPS and membranes in water
Chatrchyan, Serguei
2014-03-05
Double parton scattering is investigated in proton-proton collisions at √s = 7 TeV where the final state includes a W boson, which decays into a muon and a neutrino, and two jets. The data sample corresponds to an integrated luminosity of 5 fb–1, collected with the CMS detector at the LHC. Observables sensitive to double parton scattering are investigated after being corrected for detector effects and selection efficiencies. The fraction of W + 2-jet events due to double parton scattering is measured to be 0.055 +/- 0.002 (stat.) +/- 0.014 (syst.). Finally, the effective cross section, σeff, characterizing the effectivemore » transverse area of hard partonic interactions in collisions between protons is measured to be 20.7 +/- 0.8 (stat.) +/- 6.6 (syst.) mb.« less
Chatrchyan, Serguei
2014-03-05
Double parton scattering is investigated in proton-proton collisions at √s = 7 TeV where the final state includes a W boson, which decays into a muon and a neutrino, and two jets. The data sample corresponds to an integrated luminosity of 5 fb^{–1}, collected with the CMS detector at the LHC. Observables sensitive to double parton scattering are investigated after being corrected for detector effects and selection efficiencies. The fraction of W + 2-jet events due to double parton scattering is measured to be 0.055 +/- 0.002 (stat.) +/- 0.014 (syst.). Finally, the effective cross section, σ_{eff}, characterizing the effective transverse area of hard partonic interactions in collisions between protons is measured to be 20.7 +/- 0.8 (stat.) +/- 6.6 (syst.) mb.
NASA Astrophysics Data System (ADS)
Dhal, Satyanarayan; Chatterjee, Shyamal; Samarin, Sergey; Williams, James F.; Giebels, Franz; Gollisch, Herbert; Feder, Roland
2015-02-01
The energy and azimuthal angle dependencies of the asymmetry of spin-polarized low-energy electrons ((00) beam) elastically scattered from a W(110) surface, have been studied before and after irradiated with slow Ar+ ions with energies of 200 eV, 500 eV and 1 keV at a fluence of 5 × 1015 ions/cm2. The energy dependence of the scattered electron asymmetries and intensities (for a fixed azimuthal angle of 55°, which is determined by the angle between the normal to the scattering plane and the [?] direction in the surface of the W(110) crystal) and the azimuthal angle dependence of the asymmetry for two different incident electron energies of 14 eV and 23 eV showed a significant change after irradiation. The low-energy ion irradiation influenced the spin-polarized electron scattering more than the higher energy ions. The reason for the change of spin-dependent electron scattering is a quenching of coherent elastic multiple scattering, mainly due to lattice defects induced by implanted ions. Thus, these modifications demonstrate a technological way to construct spin-active interface with required properties. The agreement between experimental results and theoretical ones with and without multiple scattering provides a consistent explanation of the observations.
Wide angle Compton scattering on the proton: study of power suppressed corrections
NASA Astrophysics Data System (ADS)
Kivel, N.; Vanderhaeghen, M.
2015-10-01
We study the wide angle Compton scattering process on a proton within the soft-collinear factorization (SCET) framework. The main purpose of this work is to estimate the effect due to certain power suppressed corrections. We consider all possible kinematical power corrections and also include the subleading amplitudes describing the scattering with nucleon helicity flip. Under certain assumptions we present a leading-order factorization formula for these amplitudes which includes the hard- and soft-spectator contributions. We apply the formalism and perform a phenomenological analysis of the cross section and asymmetries in the wide angle Compton scattering on a proton. We assume that in the relevant kinematical region where -t,-u>2.5 GeV2 the dominant contribution is provided by the soft-spectator mechanism. The hard coefficient functions of the corresponding SCET operators are taken in the leading-order approximation. The analysis of existing cross section data shows that the contribution of the helicity-flip amplitudes to this observable is quite small and comparable with other expected theoretical uncertainties. We also show predictions for double polarization observables for which experimental information exists.
Measuring the Spin-Polarizabilities of the Proton in Polarized Compton scattering at MAMI-Mainz
NASA Astrophysics Data System (ADS)
Miskimen, Rory; A2 Collaboration
2013-10-01
At O (ω3) four new structure constants are present in the nucleon Compton scattering amplitude; these are the spin-polarizabilities γE 1 E 1, γM 1 M 1, γE 1 M 2, and γM 1 E 2. The most model independent way to determine the spin-polarizabilities is by measuring a double-polarized Compton scattering asymmetry with polarized target and circularly polarized photons, and by measuring an in-plane/transverse-plane Compton scattering asymmetry with linearly polarized photons (Σ3) . This talk will present new Compton scattering asymmetry data taken in the Δ region by the A2 Collaboration using the Crystal Ball at Mainz, with transverse polarized proton target and circularly polarized photons, the Σ2 x asymmetry (1). A dispersion model and an EFT calculation of Compton scattering are used to fit the four spin-polarizabilities to the new experimental data on Σ2 x, earlier results (2) on Σ3, and previous determinations of γ0 and γπ. The results of the fits are compared with theoretical calculations.
NASA Astrophysics Data System (ADS)
Jablonski, A.; Salvat, F.; Powell, C. J.
2004-06-01
We have analyzed differential cross sections (DCSs) for the elastic scattering of electrons by neutral atoms that have been derived from two commonly used atomic potentials: the Thomas-Fermi-Dirac (TFD) potential and the Dirac-Hartree-Fock (DHF) potential. DCSs from the latter potential are believed to be more accurate. We compared DCSs for six atoms (H, Al, Ni, Ag, Au, and Cm) at four energies (100, 500, 1000, and 10 000 eV) from two databases issued by the National Institute of Standards and Technology in which DCSs had been obtained from the TFD and DHF potentials. While the DCSs from the two potentials had similar shapes and magnitudes, there can be pronounced deviations (up to 70%) for small scattering angles for Al, Ag, Au, and Cm. In addition, there were differences of up to 400% at scattering angles for which there were deep minima in the DCSs; at other angles, the differences were typically less than 20%. The DCS differences decreased with increasing electron energy. DCSs calculated from the two potentials were compared with measured DCSs for six atoms (He, Ne, Ar, Kr, Xe, and Hg) at energies between 50 eV and 3 keV. For Ar, the atom for which experimental data are available over the largest energy range there is good agreement between the measured DCSs and those calculated from the TFD and DHF potentials at 2 and 3 keV, but the experimental DCSs agree better with the DCSs from the DHF potential at lower energies. A similar trend is found for the other atoms. At energies less than about 1 keV, there are increasing differences between the measured DCSs and the DCSs calculated from the DHF potential. These differences were attributed to the neglect of absorption and polarizability effects in the calculations. We compare transport cross sections for H, Al, Ni, Ag, Au, and Cm obtained from the DCSs for each potential. For energies between 200 eV and 1 keV, the largest differences are about 20% (for H, Au, and Cm); at higher energies, the differences are
Kiss, G. G.; Fueloep, Zs.; Gyuerky, Gy.; Elekes, Z.; Farkas, J.; Somorjai, E.; Mohr, P.; Yalcin, C.; Galaviz, D.; Gueray, R. T.; Oezkan, N.; Goerres, J.
2011-06-15
The elastic scattering cross sections for the reactions {sup 110,116}Cd({alpha},{alpha}){sup 110,116}Cd at energies above and below the Coulomb barrier are presented to provide a sensitive test for the {alpha}-nucleus optical potential parameter sets. Additional constraints for the optical potential are taken from the analysis of elastic scattering excitation functions at backward angles which are available in literature. Moreover, the variation of the elastic {alpha} scattering cross sections along the Z=48 isotopic and N=62 isotonic chain is investigated by the study of the ratios of the {sup 106,110,116}Cd({alpha},{alpha}){sup 106,110,116}Cd scattering cross sections at E{sub cm{approx_equal}}15.6and18.8 MeV and the ratio of the {sup 110}Cd({alpha},{alpha}){sup 110}Cd and {sup 112}Sn({alpha},{alpha}){sup 112}Sn reaction cross sections at E{sub cm{approx_equal}}18.8 MeV, respectively. These ratios are sensitive probes for the {alpha}-nucleus optical potential parametrizations. The potentials under study are a basic prerequisite for the prediction of {alpha}-induced reaction cross sections (e.g., for the calculation of stellar reaction rates in the astrophysical p or {gamma} process).
Passively scattered proton beam entrance dosimetry with a plastic scintillation detector
Wootton, Landon; Holmes, Charles; Sahoo, Narayan; Beddar, Sam
2015-01-01
We tested the feasibility of using plastic scintillation detectors (PSDs) for proton entrance dosimetry. A PSD built with BCF-12 scintillating fiber was used to measure the absolute entrance dose of a passively scattered proton beam for energies ranging from 140 MeV to 250 MeV, and for a range of spread out Bragg peak (SOBP) widths at 2 energies, to quantify the effect of ionization quenching on the response of the detector and to determine the necessity of Cerenkov radiation correction in proton beams. The overall accuracy and precision of the PSD was evaluated by measuring lateral beam profiles and comparing the results with profiles measured using film. The PSD under-responded owing to ionization quenching, exhibiting approximately a 7% loss of signal at the highest energy studied (250 MeV) and a 10% loss of signal at the lowest energy studied (140 MeV). For a given nominal energy, varying the SOBP width did not significantly alter the response of the PSD. Cerenkov radiation contributed negligibly to the PSD signal and can be safely ignored without introducing more than 1% error in the measured dose. Profiles measured with the PSD and film agreed to within the uncertainty of the detector, demonstrating good relative accuracy. Although correction factors were necessary to account for ionization quenching, the magnitude of the correction varied minimally over a broad range of energies; PSDs therefore represent a practical detector for proton entrance dosimetry. PMID:25591037
Passively scattered proton beam entrance dosimetry with a plastic scintillation detector
NASA Astrophysics Data System (ADS)
Wootton, Landon; Holmes, Charles; Sahoo, Narayan; Beddar, Sam
2015-02-01
We tested the feasibility of using plastic scintillation detectors (PSDs) for proton entrance dosimetry. A PSD built with BCF-12 scintillating fiber was used to measure the absolute entrance dose of a passively scattered proton beam for energies ranging from 140 to 250 MeV, and for a range of spread out Bragg peak (SOBP) widths at two energies, to quantify the effect of ionization quenching on the response of the detector and to determine the necessity of Cerenkov radiation correction in proton beams. The overall accuracy and precision of the PSD was evaluated by measuring lateral beam profiles and comparing the results with profiles measured using film. The PSD under-responded owing to ionization quenching, exhibiting approximately a 7% loss of signal at the highest energy studied (250 MeV) and a 10% loss of signal at the lowest energy studied (140 MeV). For a given nominal energy, varying the SOBP width did not significantly alter the response of the PSD. Cerenkov radiation contributed negligibly to the PSD signal and can be safely ignored without introducing more than 1% error in the measured dose. Profiles measured with the PSD and film agreed to within the uncertainty of the detector, demonstrating good relative accuracy. Although correction factors were necessary to account for ionization quenching, the magnitude of the correction varied minimally over a broad range of energies; PSDs therefore represent a practical detector for proton entrance dosimetry.
Relativistic proton-nucleus scattering and one-boson-exchange models
NASA Technical Reports Server (NTRS)
Maung, Khin Maung; Gross, Franz; Tjon, J. A.; Townsend, L. W.; Wallace, S. J.
1993-01-01
Relativistic p-(Ca-40) elastic scattering observables are calculated using four sets of relativistic NN amplitudes obtained from different one-boson-exchange (OBE) models. The first two sets are based upon a relativistic equation in which one particle is on mass shell and the other two sets are obtained from a quasipotential reduction of the Bethe-Salpeter equation. Results at 200, 300, and 500 MeV are presented for these amplitudes. Differences between the predictions of these models provide a study of the uncertainty in constructing Dirac optical potentials from OBE-based NN amplitudes.
A model for the accurate computation of the lateral scattering of protons in water.
Bellinzona, E V; Ciocca, M; Embriaco, A; Ferrari, A; Fontana, A; Mairani, A; Parodi, K; Rotondi, A; Sala, P; Tessonnier, T
2016-02-21
A pencil beam model for the calculation of the lateral scattering in water of protons for any therapeutic energy and depth is presented. It is based on the full Molière theory, taking into account the energy loss and the effects of mixtures and compounds. Concerning the electromagnetic part, the model has no free parameters and is in very good agreement with the FLUKA Monte Carlo (MC) code. The effects of the nuclear interactions are parametrized with a two-parameter tail function, adjusted on MC data calculated with FLUKA. The model, after the convolution with the beam and the detector response, is in agreement with recent proton data in water from HIT. The model gives results with the same accuracy of the MC codes based on Molière theory, with a much shorter computing time.
A model for the accurate computation of the lateral scattering of protons in water
NASA Astrophysics Data System (ADS)
Bellinzona, E. V.; Ciocca, M.; Embriaco, A.; Ferrari, A.; Fontana, A.; Mairani, A.; Parodi, K.; Rotondi, A.; Sala, P.; Tessonnier, T.
2016-02-01
A pencil beam model for the calculation of the lateral scattering in water of protons for any therapeutic energy and depth is presented. It is based on the full Molière theory, taking into account the energy loss and the effects of mixtures and compounds. Concerning the electromagnetic part, the model has no free parameters and is in very good agreement with the FLUKA Monte Carlo (MC) code. The effects of the nuclear interactions are parametrized with a two-parameter tail function, adjusted on MC data calculated with FLUKA. The model, after the convolution with the beam and the detector response, is in agreement with recent proton data in water from HIT. The model gives results with the same accuracy of the MC codes based on Molière theory, with a much shorter computing time.
The Proton Elastic Form Factor Ratio mu(p) G**p(E)/G**p(M) at Low Momentum Transfer
G. Ron; J. Glister; B. Lee; K. Allada; W. Armstrong; J. Arrington; A. Beck; F. Benmokhtar; B.L. Berman; W. Boeglin; E. Brash; A. Camsonne; J. Calarco; J. P. Chen; Seonho Choi; E. Chudakov; L. Coman; B. Craver; F. Cusanno; J. Dumas; C. Dutta; R. Feuerbach; A. Freyberger; S. Frullani; F. Garibaldi; R. Gilman; O. Hansen; D. W. Higinbotham; T. Holmstrom; C.E. Hyde; H. Ibrahim; Y. Ilieva; C. W. de Jager; X. Jiang; M. K. Jones; A. Kelleher; E. Khrosinkova; E. Kuchina; G. Kumbartzki; J. J. LeRose; R. Lindgren; P. Markowitz; S. May-Tal Beck; E. McCullough; D. Meekins; M. Meziane; Z.-E. Meziani; R. Michaels; B. Moffit; B.E. Norum; Y. Oh; M. Olson; M. Paolone; K. Paschke; C. F. Perdrisat; E. Piasetzky; M. Potokar; R. Pomatsalyuk; I. Pomerantz; A. Puckett; V. Punjabi; X. Qian; Y. Qiang; R. Ransome; M. Reyhan; J. Roche; Y. Rousseau; A. Saha; A.J. Sarty; B. Sawatzky; E. Schulte; M. Shabestari; A. Shahinyan; R. Shneor; S. ˇ Sirca; K. Slifer; P. Solvignon; J. Song; R. Sparks; R. Subedi; S. Strauch; G. M. Urciuoli; K. Wang; B. Wojtsekhowski; X. Yan; H. Yao; X. Zhan; X. Zhu
2007-11-01
High precision measurements of the proton elastic form factor ratio have been made at four-momentum transfers, Q^2, between 0.2 and 0.5 GeV^2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q^2 range the deviation from unity is primarily due to GEp being smaller than the dipole parameterization.
Liengsawangwong, Praimakorn; Sahoo, Nanayan; Ding, Xiaoning; Lii, MingFwu; Gillin, Michale T.; Zhu, Xiaorong Ronald
2015-01-01
Purpose: To evaluate the dosimetric characteristics of a two-dimensional (2D) diode array detector irradiated with passively scattered proton beams. Materials and Methods: A diode array detector, MapCHECK (Model 1175, Sun Nuclear, Melbourne, FL, USA) was characterized in passive-scattered proton beams. The relative sensitivity of the diodes and absolute dose calibration were determined using a 250 MeV beam. The pristine Bragg curves (PBCs) measured by MapCHECK diodes were compared with those of an ion chamber using a range shift method. The water-equivalent thickness (WET) of the diode array detector’s intrinsic buildup also was determined. The inverse square dependence, linearity, and other proton dosimetric quantities measured by MapCHECK were also compared with those of the ion chambers. The change in the absolute dose response of the MapCHECK as a function of accumulated radiation dose was used as an indicator of radiation damage to the diodes. 2D dose distribution with and without the compensator were measured and compared with the treatment planning system (TPS) calculations. Results: The WET of the MapCHECK diode’s buildup was determined to be 1.7 cm. The MapCHECK-measured PBC were virtually identical to those measured by a parallel-plate ion chamber for 160, 180, and 250 MeV proton beams. The inverse square results of the MapCHECK were within ±0.4% of the ion chamber results. The linearity of MapCHECK results was within 1% of those from the ion chamber as measured in the range between 10 and 300 MU. All other dosimetric quantities were within 1.3% of the ion chamber results. The 2D dose distributions for non-clinical fields without compensator and the patient treatment fields with the compensator were consistent with the TPS results. The absolute dose response of the MapCHECK was changed by 7.4% after an accumulated dose increased by 170 Gy. Conclusions: The MapCHECK is a convenient and useful tool for 2D dose distribution measurements using passively
High-precision measurement of the proton elastic form factor ratio μpGE/GM at low Q2
Zhan, X.; Allada, K.; Armstrong, D. S.; Arrington, J.; Bertozzi, W.; Boeglin, W.; Chen, J. -P.; Chirapatpimol, K.; Choi, S.; Chudakov, E.; et al
2011-10-06
Here, we report a new high precision measurement of the proton elastic form factor ratio μpGE/GM for the four-momentum transfer squared Q2 = 0.3-0.7 (GeV/c)2. The measurement was performed at Jefferson Lab (JLab) in Hall A using recoil polarimetry. With the achieved ~1% total uncertainty, the new data clearly show that the deviation of the ratio μpGE/GM from unity observed in previous polarization measurements at high Q2 continues down to the lowest Q2 value of this measurement. The updated global fit that includes the new results yields in this Q2 range an electric (magnetic) form factor ~2% smaller (~1% larger)more » than the previous global fit. We obtain new extractions of the proton electric and magnetic radii, which are (rE2)1/2 = 0.875 ± 0.010 fm and (rM2)1/2 = 0.867 ± 0.020 fm. Moreover, the charge radius is consistent with other recent extractions based on the electron-proton interaction, including the atomic hydrogen Lamb shift measruements, which suggests a missing correction in the comparison of measurements of the proton charge radius using electron probes and the recent extraction from the muonic hydrogen Lamb shift.« less
High-precision measurement of the proton elastic form factor ratio μpGE /GM at low Q2
NASA Astrophysics Data System (ADS)
Zhan, X.; Allada, K.; Armstrong, D. S.; Arrington, J.; Bertozzi, W.; Boeglin, W.; Chen, J.-P.; Chirapatpimol, K.; Choi, S.; Chudakov, E.; Cisbani, E.; Decowski, P.; Dutta, C.; Frullani, S.; Fuchey, E.; Garibaldi, F.; Gilad, S.; Gilman, R.; Glister, J.; Hafidi, K.; Hahn, B.; Hansen, J.-O.; Higinbotham, D. W.; Holmstrom, T.; Holt, R. J.; Huang, J.; Huber, G. M.; Itard, F.; de Jager, C. W.; Jiang, X.; Johnson, M.; Katich, J.; de Leo, R.; LeRose, J. J.; Lindgren, R.; Long, E.; Margaziotis, D. J.; May-Tal Beck, S.; Meekins, D.; Michaels, R.; Moffit, B.; Norum, B. E.; Olson, M.; Piasetzky, E.; Pomerantz, I.; Protopopescu, D.; Qian, X.; Qiang, Y.; Rakhman, A.; Ransome, R. D.; Reimer, P. E.; Reinhold, J.; Riordan, S.; Ron, G.; Saha, A.; Sarty, A. J.; Sawatzky, B.; Schulte, E. C.; Shabestari, M.; Shahinyan, A.; Shneor, R.; Širca, S.; Solvignon, P.; Sparveris, N. F.; Strauch, S.; Subedi, R.; Sulkosky, V.; Vilardi, I.; Wang, Y.; Wojtsekhowski, B.; Ye, Z.; Zhang, Y.
2011-11-01
We report a new, high-precision measurement of the proton elastic form factor ratio μpGE /GM for the four-momentum transfer squared Q2 = 0.3- 0.7(GeV / c) 2. The measurement was performed at Jefferson Lab (JLab) in Hall A using recoil polarimetry. With a total uncertainty of approximately 1%, the new data clearly show that the deviation of the ratio μpGE /GM from unity observed in previous polarization measurements at high Q2 continues down to the lowest Q2 value of this measurement. The updated global fit that includes the new results yields an electric (magnetic) form factor roughly 2% smaller (1% larger) than the previous global fit in this Q2 range. We obtain new extractions of the proton electric and magnetic radii, which are
Spin-Ml and El responses of nuclei probed by proton inelastic scattering
NASA Astrophysics Data System (ADS)
Tamii, Atsushi; Matsubara, Hiroaki
2014-12-01
We pick up two studies on the nuclear responses from the recent experiments of high-resolution proton inelastic scattering at the Research Center for Nuclear Physics, Osaka University; 1) study of the nuclear symmetry and the neutron skin thickness by the measurement of energy electric dipole (El) response of 208Pb, and 2) study of the tensor correlation in the ground state by the measurement of the spin-Ml responses of even-even self-conjugate nuclei in the sd-shell nuclei.
Compton-Scattering Cross Section on the Proton at High Momentum Transfer
Danagoulian, A.; Roedelbronn, M.; Chang, T.-H.; Nathan, A. M.; Mamyan, V. H.; Aniol, K. A.; Margaziotis, D. J.; Annand, J. R. M.; Hamilton, D. J.; Bertin, P. Y.; Camsonne, A.; Laveissiere, G.; Bosted, P.; Paschke, K.; Calarco, J. R.; Chang, C. C.; Horn, T.; Savvinov, N.; Chen, J.-P.
2007-04-13
Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s=5-11 and -t=2-7 GeV{sup 2} with a statistical accuracy of a few percent. The scaling power for the s dependence of the cross section at fixed center-of-mass angle was found to be 8.0{+-}0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross-section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark.
First measurements of jet production rates in deep-inelastic lepton-proton scattering
Adams, M.R.; Aied, S.; Anthony, P.L.; Baker, M.D.; Bartlett, J.; Bhatti, A.A.; Braun, H.M.; Busza, W.; Conrad, J.M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S.K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H.J.; Geesaman, D.F.; Gilman, R.; Green, M.C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V.W.; Jackson, H.E.; Jaffe, D.E.; Jancso, G.; Jansen, D.M.; Kaufman, S.; Kennedy, R.D.; Kobrak, H.G.E.; Krzywdzinski, S.; Kunori, S.; Lord, J.J.; Lubatti, H.J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Michael, D.G.; Mohr, W.; Montgomery, H.E.; Morfin, J.G.; Nickerson, R.B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F.M.; Ramberg, E.J.; Roeser, A.; Ryan, J.; Salgado, C.W.; Salvarani, A.; Schellman, H.; Schmitz, N.; Schueler, K.P.; Seyerlein, H.J.; Skuja, A.; Snow, G.A.; Soeldner-Rembold, S.; Steinberg, P.H.; Stier, H.E.; Stopa, P.; Swanson, R.A.; Talaga, R.; T
1992-08-17
The first measurements of forward multijet rates in deep-inelastic lepton scattering are presented. Data were taken with a 490-GeV muon beam incident on a hydrogen target. The jets were defined using the GADE algorithm. The measured rates are presented as a function of the jet resolution parameter {ital y}{sub cut}, and as a function of the virtual-photon--proton center-of-momentum energy {ital W}, in the range 13{le}{ital W}{le}33 GeV. Comparisons are made to the predictions of the Lund Monte Carlo programs and good agreement is obtained when QCD corrections are included in the model.
First measurements of jet production rates in deep-inelastic lepton-proton scattering
NASA Astrophysics Data System (ADS)
Adams, M. R.; Aïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jaffe, D. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kobrak, H. G.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J.; Salgado, C. W.; Salvarani, A.; Schellman, H.; Schmitz, N.; Schüler, K. P.; Seyerlein, H. J.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H.-J.; Venkataramania, H.; Vidal, M.; Wilhelm, M.; Wilkes, J.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.
1992-08-01
The first measurements of forward multijet rates in deep-inelastic lepton scattering are presented. Data were taken with a 490-GeV muon beam incident on a hydrogen target. The jets were defined using the gade algorithm. The measured rates are presented as a function of the jet resolution parameter ycut, and as a function of the virtual-photon-proton center-of-momentum energy W, in the range 13<=W<=33 GeV. Comparisons are made to the predictions of the Lund Monte Carlo programs and good agreement is obtained when QCD corrections are included in the model.
Jiang, Jian-jun; Li, He-ping; Dai, Li-dong; Hu, Hai-ying; Wang, Yan; Zhao, Chao-shuai
2015-09-01
In-situ experimental results on the elastic wave velocity of Earth materials at high pressure and high temperature in combination with data from seismic observation can help to inverse the chemical composition, state and migration of materials in Earth's interior, providing an important approach to explore information of deep earth. Applying the Brillouin scattering into the Diamond Anvil Cell (DAC) to obtain the in situ elastic wave velocities of minerals, is the important approach to investigate elastic properties of Earth's Interior. With the development of DAC technology, on the one hand, the high temperature and high pressure experimental environment to simulate different layers of the earth can be achieved; on the other hand, the optical properties of DAC made many kinds of optical analysis and test methods have been widely applied in this research field. In order to gain the elastic wave velocity under high temperature and high pressure, the accurate experimental pressure and heating temperature of the sample in the cavity should be measured and calibrated first, then the scattering signal needs to dealt with, using the Brillouin frequency shift to calculate the velocity in the sample. Combined with the lattice constants obtained from X ray technique, by a solid elastic theory, all the elastic parameters of minerals can be solved. In this paper, firstly, application of methods based on optical spectrum such as Brillouin and Raman scattering in elasticity study on materials in Earth's interior, and the basic principle and research progress of them in the velocity measurement, pressure and temperature calibration are described in detail. Secondly, principle and scope of application of two common methods of spectral pressure calibration (fluorescence and Raman spectral pressure standard) are analyzed, in addition with introduce of the application of two conventional means of temperature calibration (blackbody radiation and Raman temperature scale) in
Jiang, Jian-jun; Li, He-ping; Dai, Li-dong; Hu, Hai-ying; Wang, Yan; Zhao, Chao-shuai
2015-09-01
In-situ experimental results on the elastic wave velocity of Earth materials at high pressure and high temperature in combination with data from seismic observation can help to inverse the chemical composition, state and migration of materials in Earth's interior, providing an important approach to explore information of deep earth. Applying the Brillouin scattering into the Diamond Anvil Cell (DAC) to obtain the in situ elastic wave velocities of minerals, is the important approach to investigate elastic properties of Earth's Interior. With the development of DAC technology, on the one hand, the high temperature and high pressure experimental environment to simulate different layers of the earth can be achieved; on the other hand, the optical properties of DAC made many kinds of optical analysis and test methods have been widely applied in this research field. In order to gain the elastic wave velocity under high temperature and high pressure, the accurate experimental pressure and heating temperature of the sample in the cavity should be measured and calibrated first, then the scattering signal needs to dealt with, using the Brillouin frequency shift to calculate the velocity in the sample. Combined with the lattice constants obtained from X ray technique, by a solid elastic theory, all the elastic parameters of minerals can be solved. In this paper, firstly, application of methods based on optical spectrum such as Brillouin and Raman scattering in elasticity study on materials in Earth's interior, and the basic principle and research progress of them in the velocity measurement, pressure and temperature calibration are described in detail. Secondly, principle and scope of application of two common methods of spectral pressure calibration (fluorescence and Raman spectral pressure standard) are analyzed, in addition with introduce of the application of two conventional means of temperature calibration (blackbody radiation and Raman temperature scale) in
NASA Astrophysics Data System (ADS)
Ye, Ruichao; de Hoop, Maarten V.; Petrovitch, Christopher L.; Pyrak-Nolte, Laura J.; Wilcox, Lucas C.
2016-05-01
We develop an approach for simulating acousto-elastic wave phenomena, including scattering from fluid-solid boundaries, where the solid is allowed to be anisotropic, with the discontinuous Galerkin method. We use a coupled first-order elastic strain-velocity, acoustic velocity-pressure formulation, and append penalty terms based on interior boundary continuity conditions to the numerical (central) flux so that the consistency condition holds for the discretized discontinuous Galerkin weak formulation. We incorporate the fluid-solid boundaries through these penalty terms and obtain a stable algorithm. Our approach avoids the diagonalization into polarized wave constituents such as in the approach based on solving elementwise Riemann problems.
NASA Technical Reports Server (NTRS)
Sheu, Y. C.; Fu, L. S.
1983-01-01
The extended method of equivalent inclusions is applied to study the specific wave problems: (1) the transmission of elastic waves in an infinite medium containing a layer of inhomogeneity, and (2) the scattering of elastic waves in an infinite medium containing a perfect spherical inhomogeneity. Eigenstrains are expanded as a geometric series and a method of integration based on the inhomogeneous Helmholtz operator is adopted. This study compares results, obtained by using limited number of terms in the eigenstrain expansion, with exact solutions for the layer problem and that for a perfect sphere.
Spectroscopic information of 6Li from elastic scattering of deuterons, 3He and 4He by 6Li
NASA Astrophysics Data System (ADS)
Amar, A.
2014-07-01
The elastic scattering of deuterons, 3He and 4He on 6Li at different incident energies have been analyzed in the framework of the optical model (OM) using ECIS88 as well as SPI GENOA codes. The optical potential parameters were extracted in the phenomenological treatment. A good agreement between theoretical and experimental differential cross-sections was obtained in whole angular range. Parameters for real part of potential have been also calculated microscopically with double-folding model for the d, 3He and 4He scattering, respectively, using DFPOT code. The elastic transfer mechanism has been studied by coupled reaction channel (CRC) method using FRESCO code. Spectroscopic amplitudes of 6Li ≡ t + 3He and 6Li ≡ α + d configurations have been extracted from d, 3He and 4He scattering on 6Li at wide energy range. A comparison between spectroscopic amplitudes obtained from deuteron and α elastically scattering from 6Li has been made. The extracted spectroscopic amplitudes of 6Li ≡ 4He + d(SF = SA2) from 6Li(d, 6Li)d and 6Li(α, 6Li)α are not the same as expected theoretically.
Peripheral elastic and inelastic scattering of {sup 17,18}O on light targets at 12 MeV/nucleon
Carstoiu, F.; Al-Abdullah, T.; Gagliardi, C. A.; Trache, L.
2015-02-24
The elastic and inelastic scattering of {sup 17,18}O with light targets has been undertaken at 12 MeV/nucleon in order to determine the optical potentials needed for the transfer reaction {sup 13}C({sup 17}O,{sup 18}O){sup 12}C. Optical potentials in both incoming and outgoing channels have been determined in a single experiment. This transfer reaction was used to infer the direct capture rate to the {sup 17}F(p,γ){sup 18}Ne which is essential to estimate the production of {sup 18}F at stellar energies in ONe novae. We demonstrate the stability of the ANC method and OMP results using good quality elastic and inelastic scattering data with stable beams. The peripherality of our reaction is inferred from a semiclassical decomposition of the total scattering amplitude into barrier and internal barrier components. Comparison between elastic scattering of {sup 17}O, {sup 18}O and {sup 16}O projectiles is made.
NASA Astrophysics Data System (ADS)
Gaebler, Peter J.; Eulenfeld, Tom; Wegler, Ulrich
2015-12-01
In this study, frequency-dependent seismic scattering and intrinsic attenuation parameters for the crustal structure beneath the W-Bohemia/Vogtland swarm earthquake region close to the border of Czech Republic and Germany are estimated. Synthetic seismogram envelopes are modelled using elastic and acoustic radiative transfer theory. Scattering and absorption parameters are determined by fitting these synthetic envelopes to observed seismogram envelopes from 14 shallow local events from the October 2008 W-Bohemia/Vogtland earthquake swarm. The two different simulation approaches yield similar results for the estimated crustal parameters and show a comparable frequency dependence of both transport mean free path and intrinsic absorption path length. Both methods suggest that intrinsic attenuation is dominant over scattering attenuation in the W-Bohemia/Vogtland region for the investigated epicentral distance range and frequency bands from 3 to 24 Hz. Elastic simulations of seismogram envelopes suggest that forward scattering is required to explain the data, however, the degree of forward scattering is not resolvable. Errors in the parameter estimation are smaller in the elastic case compared to results from the acoustic simulations. The frequency decay of the transport mean free path suggests a random medium described by a nearly exponential autocorrelation function. The fluctuation strength and correlation length of the random medium cannot be estimated independently, but only a combination of the parameters related to the transport mean free path of the medium can be computed. Furthermore, our elastic simulations show, that using our numerical method, it is not possible to resolve the value of the mean free path of the random medium.
Bae, Euiwon; Patsekin, Valery; Rajwa, Bartek; Bhunia, Arun K.; Holdman, Cheryl; Davisson, V. Jo; Hirleman, E. Daniel; Robinson, J. Paul
2012-01-01
A microbial high-throughput screening (HTS) system was developed that enabled high-speed combinatorial studies directly on bacterial colonies. The system consists of a forward scatterometer for elastic light scatter (ELS) detection, a plate transporter for sample handling, and a robotic incubator for automatic incubation. To minimize the ELS pattern-capturing time, a new calibration plate and correction algorithms were both designed, which dramatically reduced correction steps during acquisition of the circularly symmetric ELS patterns. Integration of three different control software programs was implemented, and the performance of the system was demonstrated with single-species detection for library generation and with time-resolved measurement for understanding ELS colony growth correlation, using Escherichia coli and Listeria. An in-house colony-tracking module enabled researchers to easily understand the time-dependent variation of the ELS from identical colony, which enabled further analysis in other biochemical experiments. The microbial HTS system provided an average scan time of 4.9 s per colony and the capability of automatically collecting more than 4000 ELS patterns within a 7-h time span. PMID:22559555
Elasticity of the eye's crystalline lens: A Brillouin light scattering study.
NASA Astrophysics Data System (ADS)
Bailey, S.; Gump, J.; Sooryakumar, R.; Jayaprakash, C.; Venkiteshwar, M. S.; Bullimore, M.; Twa, M.
2009-03-01
Focusing the eye on a near object results in an increase in its optical power brought about by contraction of the ciliary muscles and an increase in the lens surface curvature. Distant vision occurs when the muscular force flattens the lens. Central to the ability of the lens to alter shape are its mechanical properties. Thus, given that hardening of the lens would impede deformation and reduce its ability to undergo the changes required for accommodation, a noninvasive approach to measure the elastic properties of the lens is valuable. We present results of Brillouin scattering from bovine and human lenses (from the organ donor program at The Ohio State University) that measure their high frequency acoustic response. These measurements are conducted with a few milli-watts of laser power and, in the case of bovine lenses, from entire intact eye globes, allow the stiffness of the lens to be mapped across its cross-section. The results will be compared to values of the shear- and bulk-moduli determined from other techniques and the implications of differences in these moduli discussed.
Molecular dynamics force-field refinement against quasi-elastic neutron scattering data
Borreguero Calvo, Jose M.; Lynch, Vickie E.
2015-11-23
Quasi-elastic neutron scattering (QENS) is one of the experimental techniques of choice for probing the dynamics at length and time scales that are also in the realm of full-atom molecular dynamics (MD) simulations. This overlap enables extension of current fitting methods that use time-independent equilibrium measurements to new methods fitting against dynamics data. We present an algorithm that fits simulation-derived incoherent dynamical structure factors against QENS data probing the diffusive dynamics of the system. We showcase the difficulties inherent to this type of fitting problem, namely, the disparity between simulation and experiment environment, as well as limitations in the simulationmore » due to incomplete sampling of phase space. We discuss a methodology to overcome these difficulties and apply it to a set of full-atom MD simulations for the purpose of refining the force-field parameter governing the activation energy of methyl rotation in the octa-methyl polyhedral oligomeric silsesquioxane molecule. Our optimal simulated activation energy agrees with the experimentally derived value up to a 5% difference, well within experimental error. We believe the method will find applicability to other types of diffusive motions and other representation of the systems such as coarse-grain models where empirical fitting is essential. In addition, the refinement method can be extended to the coherent dynamic structure factor with no additional effort.« less
Time-frequency analysis of the bistatic acoustic scattering from a spherical elastic shell.
Anderson, Shaun D; Sabra, Karim G; Zakharia, Manell E; Sessarego, Jean-Pierre
2012-01-01
The development of low-frequency sonar systems, using, for instance, a network of autonomous systems in unmanned vehicles, provides a practical means for bistatic measurements (i.e., when the source and receiver are widely separated) allowing for multiple viewpoints of the target of interest. Time-frequency analysis, in particular, Wigner-Ville analysis, takes advantage of the evolution time dependent aspect of the echo spectrum to differentiate a man-made target, such as an elastic spherical shell, from a natural object of the similar shape. A key energetic feature of fluid-loaded and thin spherical shell is the coincidence pattern, also referred to as the mid-frequency enhancement (MFE), that results from antisymmetric Lamb-waves propagating around the circumference of the shell. This article investigates numerically the bistatic variations of the MFE with respect to the monostatic configuration using the Wigner-Ville analysis. The observed time-frequency shifts of the MFE are modeled using a previously derived quantitative ray theory by Zhang et al. [J. Acoust. Soc. Am. 91, 1862-1874 (1993)] for spherical shell's scattering. Additionally, the advantage of an optimal array beamformer, based on joint time delays and frequency shifts is illustrated for enhancing the detection of the MFE recorded across a bistatic receiver array when compared to a conventional time-delay beamformer.
Hybrid Theory of P-Wave Electron-Hydrogen Elastic Scattering
NASA Technical Reports Server (NTRS)
Bhatia, Anand
2012-01-01
We report on a study of electron-hydrogen scattering, using a combination of a modified method of polarized orbitals and the optical potential formalism. The calculation is restricted to P waves in the elastic region, where the correlation functions are of Hylleraas type. It is found that the phase shifts are not significantly affected by the modification of the target function by a method similar to the method of polarized orbitals and they are close to the phase shifts calculated earlier by Bhatia. This indicates that the correlation function is general enough to include the target distortion (polarization) in the presence of the incident electron. The important fact is that in the present calculation, to obtain similar results only 35-term correlation function is needed in the wave function compared to the 220-term wave function required in the above-mentioned previous calculation. Results for the phase shifts, obtained in the present hybrid formalism, are rigorous lower bounds to the exact phase shifts.
Quasi-Elastic Neutron Scattering: an insight into life at extreme conditions
NASA Astrophysics Data System (ADS)
Foglia, Fabrizia; Hazael, Rachael; Simeoni, Giovanna; Appavou, Marie-Sousai; Meersman, Filip; Daniel, Isabelle; Forsyth, Trevor; McMillan, Paul
2013-06-01
Microbes have been found to thrive in diverse environments characterised by a wide range of pressure-temperature-composition conditions. The range of physicochemical conditions under which microbial life has been observed has continually expanded as microbiologists explore additional remote and apparently hostile environments. The studies provide us with clues about the current extent of biological organisms and allow us to explore the fundamental limits to survival of bacterial life forms under extreme conditions. We are developing quasi-elastic neutron scattering (QENS) studies to help us to understand the dynamic processes associated with H-/D-containing microbes under high P conditions. We have begun our study using samples of Shewanella oneidensis. We obtained pioneering QENS results carried out in situ on live organisms into the 200 MPa range that provide new information on H2O/D2O exchange dynamics across the cell walls. To achieve this result we prepared D2O-substituted bacteria within the Deuteration Facility in Grenoble and transferred samples to the Munich FRM-II neutron reactor for QENS experiments at the high resolution TOFTOF spectrometer station. Our initial results show clear P dependence of H2O/D2O transfer dynamics across the bacterial cell walls. DCO
NASA Astrophysics Data System (ADS)
Bae, Euiwon; Patsekin, Valery; Rajwa, Bartek; Bhunia, Arun K.; Holdman, Cheryl; Davisson, V. Jo; Hirleman, E. Daniel; Robinson, J. Paul
2012-04-01
A microbial high-throughput screening (HTS) system was developed that enabled high-speed combinatorial studies directly on bacterial colonies. The system consists of a forward scatterometer for elastic light scatter (ELS) detection, a plate transporter for sample handling, and a robotic incubator for automatic incubation. To minimize the ELS pattern-capturing time, a new calibration plate and correction algorithms were both designed, which dramatically reduced correction steps during acquisition of the circularly symmetric ELS patterns. Integration of three different control software programs was implemented, and the performance of the system was demonstrated with single-species detection for library generation and with time-resolved measurement for understanding ELS colony growth correlation, using Escherichia coli and Listeria. An in-house colony-tracking module enabled researchers to easily understand the time-dependent variation of the ELS from identical colony, which enabled further analysis in other biochemical experiments. The microbial HTS system provided an average scan time of 4.9 s per colony and the capability of automatically collecting more than 4000 ELS patterns within a 7-h time span.
Diagnosis of breast cancer using elastic-scattering spectroscopy: preliminary clinical results
NASA Astrophysics Data System (ADS)
Bigio, Irving J.; Brown, Stephen G.; Briggs, Gavin M.; Kelley, Christine; Lakhani, Sunil; Pickard, David; Ripley, Paul M.; Rose, Ian; Saunders, Christobel
2000-04-01
We report on the first stages of a clinical study designed to test elastic-scattering spectroscopy, medicated by fiberoptic probes, for three specific clinical applications in breast-tissue diagnosis: (1) a transdermal-needle (interstitial) measurement for instant diagnosis with minimal invasiveness similar to fine-needle aspiration but with sensitivity to a larger tissue volume, (2) a hand-held diagnostic probe for use in assessing tumor/resection margins during open surgery, and (3) use of the same probe for real-time assessment of the `sentinel' node during surgery to determine the presence or absence of tumor (metastatic). Preliminary results from in vivo measurements on 31 women are encouraging. Optical spectra were measured on 72 histology sites in breast tissue, and 54 histology sites in sentinel nodes. Two different artificial intelligence methods of spectral classification were studied. Artificial neural networks yielded sensitivities of 69% and 58%, and specificities of 85% and 93%, for breast tissue and sentinel nodes, respectively. Hierarchical cluster analysis yielded sensitivities of 67% and 91%, and specificities of 79% and 77%, for breast tissue and sentinel nodes, respectively. These values are expected to improve as the data sets continue to grow and more sophisticated data preprocessing is employed. The study will enroll up to 400 patients over the next two years.
NASA Astrophysics Data System (ADS)
Akimov, D. Yu; Berdnikova, A. K.; Belov, V. A.; Bolozdynya, A. I.; Burenkov, A. A.; Efremenko, Yu V.; Gusakov, Yu V.; Etenko, A. V.; Kaplin, V. A.; Khromov, A. V.; Konovalov, A. M.; Kovalenko, A. G.; Kozlova, E. S.; Kumpan, A. V.; Krakhmalova, T. D.; Melikyan, Yu A.; Naumov, P. P.; Rudik, D. G.; Shafigullin, R. R.; Shakirov, A. V.; Simakov, G. E.; Sosnovtsev, V. V.; Stekhanov, V. N.; Tobolkin, A. A.; Tolstukhin, I. A.
2016-02-01
The RED-100 (Russian Emission Detector) is being constructed for the experiment to search for elastic coherent neutrino scattering off atomic nuclei. This fundamental process was predicted several decades ago by the Standard Model of electroweak interactions but has not been discovered yet. The RED-100 is a two-phase emission xenon detector containing ∼200 kg of the liquid Xe (∼ 100 kg of that is in a fiducial volume). One of the possible sites to carry out the experiment is the SNS (Spallation Neutron Source) facility at Oak Ridge National Laboratory, USA. SNS is the world's most intense pulsed source of neutrinos and unique place to study neutrino properties. The energy spectrum of neutrinos produced at the SNS extends up to ∼ 50 MeV and satisfies coherence condition. These neutrinos give kinetic energies of Xe recoils up to a few tens of keV where the response of nuclear recoils is well-known from neutron calibrations of dark matter detectors. The detector will be deployed in the basement under the experimental hall at a distance of ∼30 meters from the SNS target. The expected signal and background (neutron and gamma) are estimated for this specific location. The detector details, current status and future plans are provided.
Molecular dynamics force-field refinement against quasi-elastic neutron scattering data
Borreguero Calvo, Jose M.; Lynch, Vickie E.
2015-11-23
Quasi-elastic neutron scattering (QENS) is one of the experimental techniques of choice for probing the dynamics at length and time scales that are also in the realm of full-atom molecular dynamics (MD) simulations. This overlap enables extension of current fitting methods that use time-independent equilibrium measurements to new methods fitting against dynamics data. We present an algorithm that fits simulation-derived incoherent dynamical structure factors against QENS data probing the diffusive dynamics of the system. We showcase the difficulties inherent to this type of fitting problem, namely, the disparity between simulation and experiment environment, as well as limitations in the simulation due to incomplete sampling of phase space. We discuss a methodology to overcome these difficulties and apply it to a set of full-atom MD simulations for the purpose of refining the force-field parameter governing the activation energy of methyl rotation in the octa-methyl polyhedral oligomeric silsesquioxane molecule. Our optimal simulated activation energy agrees with the experimentally derived value up to a 5% difference, well within experimental error. We believe the method will find applicability to other types of diffusive motions and other representation of the systems such as coarse-grain models where empirical fitting is essential. In addition, the refinement method can be extended to the coherent dynamic structure factor with no additional effort.
Acoustic scattering by elastic cylinders of elliptical cross-section and splitting up of resonances
Ancey, S. Bazzali, E. Gabrielli, P. Mercier, M.
2014-05-21
The scattering of a plane acoustic wave by an infinite elastic cylinder of elliptical cross section is studied from a modal formalism by emphasizing the role of the symmetries. More precisely, as the symmetry is broken in the transition from the infinite circular cylinder to the elliptical one, the splitting up of resonances is observed both theoretically and experimentally. This phenomenon can be interpreted using group theory. The main difficulty stands in the application of this theory within the framework of the vectorial formalism in elastodynamics. This method significantly simplifies the numerical treatment of the problem, provides a full classification of the resonances, and gives a physical interpretation of the splitting up in terms of symmetry breaking. An experimental part based on ultrasonic spectroscopy complements the theoretical study. A series of tank experiments is carried out in the case of aluminium elliptical cylinders immersed in water, in the frequency range 0 ≤ kr ≤ 50, where kr is the reduced wave number in the fluid. The symmetry is broken by selecting various cylinders of increasing eccentricity. More precisely, the greater the eccentricity, the higher the splitting up of resonances is accentuated. The experimental results provide a very good agreement with the theoretical ones, the splitting up is observed on experimental form functions, and the split resonant modes are identified on angular diagrams.
Elastic scattering spectroscopy in vivo: optical biopsies of cancers of the breast and GI tract
NASA Astrophysics Data System (ADS)
Pickard, David C. O.; Briggs, Gavin M.; Saunders, Christobel; Lakhani, Sunil; Ripley, Paul M.; Bigio, Irving J.; Bown, Stephen G.
2000-04-01
Elastic scattering or diffuse reflectance spectroscopy offers the possibility of distinguishing between normal and neoplastic tissue with a relatively simple optical measurement. The measurement of the reflection of light has previously been shown to be sensitive to the size and distribution of both intra and inter-cellular structures as well as absorption from chromatophores which are present in the tissue. By coupling a white light source and spectrometer to optic fibers it is possible to construct probes which can be inserted precutaneously or intra- operatively into breast tissue or which can pass down the channel of an endoscope and take in-vivo spectra of diseased and normal tissue in the Gastro-Intestinal tract. Spectra are reported from a large number of patients with a variety of benign, metaplastic, dysplastic and cancerous conditions. Some differences that have been observed in these spectra are discussed and the merits and disadvantages of 'optical biopsy' as an in-vivo diagnostic tool are examined. It is shown that to a relatively high degree of sensitivity and specificity it is possible to distinguish cancerous from normal tissue in a number of cases. The methods of distinguishing spectra and some possible modalities for their improvement are discussed.
Cullen, D.E.
1994-08-01
The computer code WALKMAN performs electron single collision elastic scattering Monte Carlo calculations in spherical or planar geometry. It is intended as a research tool to obtain results that can be compared to the results of condensed history calculations. This code is designed to be self documenting, in the sense that the latest documentation is included as comment lines at the beginning of the code. Printed documentation, such as this document, is periodically published and consists mostly of a copy of the comment lines from the code. The user should be aware that the comment lines within the code are continually updated to reflect the most recent status of the code and these comments should always be considered to be the most recent documentation for the code and may supersede published documentation, such as this document. Therefore, the user is advised to always read the documentation within the actual code. The remainder of this report consists of example results and a listing of the documentation which appears at the beginning of the code.
Anti-Neutrino Charged Current Quasi-Elastic Scattering in MINER$\
Chvojka, Jesse John
2012-01-01
The phenomenon of neutrino oscillation is becoming increasingly understood with results from accelerator-based and reactor-based experiments, but unanswered questions remain. The proper ordering of the neutrino mass eigenstates that compose the neutrino avor eigenstates is not completely known. We have yet to detect CP violation in neutrino mixing, which if present could help explain the asymmetry between matter and anti-matter in the universe. We also have not resolved whether sterile neutrinos, which do not interact in any Standard Model interaction, exist. Accelerator-based experiments appear to be the most promising candidates for resolving these questions; however, the ability of present and future experiments to provide answers is likely to be limited by systematic errors. A significant source of this systematic error comes from limitations in our knowledge of neutrino-nucleus interactions. Errors on cross-sections for such interactions are large, existing data is sometimes contradictory, and knowledge of nuclear effects is incomplete. One type of neutrino interaction of particular interest is charged current quasi-elastic (CCQE) scattering, which yields a final state consisting of a charged lepton and nucleon. This process, which is the dominant interaction near energies of 1 GeV, is of great utility to neutrino oscillation experiments since the incoming neutrino energy and the square of the momentum transferred to the final state nucleon, Q^{2}, can be reconstructed using the final state lepton kinematics. To address the uncertainty in our knowledge of neutrino interactions, many experiments have begun making dedicated measurements. In particular, the MINER A experiment is studying neutrino-nucleus interactions in the few GeV region. MINERvA is a fine-grained, high precision, high statistics neutrino scattering experiment that will greatly improve our understanding of neutrino cross-sections and nuclear effects that affect the final state particles
A procedure for calculation of monitor units for passively scattered proton radiotherapy beams
Sahoo, Narayan; Zhu, X. Ronald; Arjomandy, Bijan; Ciangaru, George; Lii, MingFwu; Amos, Richard; Wu, Richard; Gillin, Michael T.
2008-11-15
The purpose of this study is to validate a monitor unit (MU) calculation procedure for passively scattered proton therapy beams. The output dose per MU (d/MU) of a therapeutic radiation beam is traditionally calibrated under specific reference conditions. These conditions include beam energy, field size, suitable depth in water or water equivalent phantom in a low dose gradient region with known relative depth dose, and source to point of calibration distance. Treatment field settings usually differ from these reference conditions leading to a different d/MU that needs to be determined for delivering the prescribed dose. For passively scattered proton beams, the proton specific parameters, which need to be defined, are related to the energy, lateral scatterers, range modulating wheel, spread out Bragg peak (SOBP) width, thickness of any range shifter, the depth dose value relative to the normalization point in the SOBP, and scatter both from the range compensator and inhomogeneity in the patient. Following the custom for photons or electrons, a set of proton dosimetry factors, representing the changes in the d/MU relative to a reference condition, can be defined as the relative output factor (ROF), SOBP factor (SOBPF), range shifter factor (RSF), SOBP off-center factor (SOBPOCF), off-center ratio (OCR), inverse square factor (ISF), field size factor (FSF), and compensator and patient scatter factor (CPSF). The ROF, SOBPF, and RSF are the major contributors to the d/MU and were measured using an ion chamber in water tank during the clinical commissioning of each beam to create a dosimetry beam data table to be used for calculating the monitor units. The following simple formula is found to provide an independent method to determine the d/MU at the point of interest (POI) in the patient, namely, (d/MU)=ROF{center_dot}SOBPF{center_dot}RSF{center_dot}SOBPOCF{center_dot}OCR{center_dot}FSF{center_dot}ISF{center_dot}CPSF. The monitor units for delivering the intended dose
Wuttke, Joachim
2012-10-01
In a recent contribution to this journal, Magazù, Migliardo, and Benedetto suggest to determine relaxation times from inflection points in the elastic neutron scattering intensity as function of (1) resolution time or (2) temperature. Method (1) can be generalized into a scaling law. Method (2) is only approximately valid; its application to protein data does not back a wavenumber-independent dynamic transition.