Science.gov

Sample records for proton elastic scattering

  1. Proton Nucleus Elastic Scattering Data.

    Energy Science and Technology Software Center (ESTSC)

    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.

  2. Elastic proton-proton scattering at RHIC

    SciTech Connect

    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.

  3. 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.

  4. 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.

  5. Proton-Proton Elastic Scattering Excitation Functions at Intermediate Energies

    SciTech Connect

    Bisplinghoff, J.; Daniel, R.; Diehl, O.; Engelhardt, H.; Ernst, J.; Eversheim, P.; Gro-Hardt, R.; Heider, S.; Heine, A.; Hinterberger, F.; Jahn, R.; Jeske, M.; Lahr, U.; Maschuw, R.; Mayer-Kuckuk, T.; Mosel, F.; Rohdje, H.; Rosendaal, D.; Ro, U.; Scheid, H.; Schulz-Rojahn, M.; Schwandt, F.; Schwarz, V.; Trelle, H.; Wiedmann, W.; Ziegler, R.; Albers, D.; Bollmann, R.; Bueer, K.; Dohrmann, F.; Gasthuber, M.; Greiff, J.; Gro, A.; Igelbrink, M.; Langkau, R.; Lindlein, J.; Mueller, M.; Muenstermann, M.; Schirm, N.; Scobel, W.; Wellinghausen, A.; Woller, K.; Cloth, P.; Gebel, R.; Maier, R.; Prasuhn, D.; von Rossen, P.; Sterzenbach, G.

    1997-03-01

    Excitation functions of proton-proton elastic scattering cross sections have been measured in narrow steps for projectile momenta p{sub p} (energies T{sub p}) from 1100 to 3300MeV/c (500 to 2500MeV) in the angular range 35{degree}{le}{Theta}{sub c.m.}{le}90{degree} with a detector providing {Delta}{Theta}{sub c.m.}{approx}1.4{degree} resolution. Measurements have been performed continuously during projectile acceleration in the cooler synchrotron COSY with an internal CH{sub 2} fiber target, taking particular care to monitor luminosity as a function of T{sub p}. The advantages of this experimental technique are demonstrated, and the excitation functions obtained are compared to existing cross section data. No evidence for narrow structures was found. {copyright} {ital 1997} {ital The American Physical Society}

  6. Two-photon exchange and elastic electron-proton scattering

    SciTech Connect

    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.

  7. Electron- and positron-proton elastic scattering in CLAS

    SciTech Connect

    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.

  8. Electron- and positron-proton elastic scattering in CLAS

    SciTech Connect

    Weinstein, L. B.

    2009-09-02

    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.

  9. 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

  10. Parity Violation in Forward Angle Elastic Electron Proton Scattering

    SciTech Connect

    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.

  11. Proton-proton and proton-antiproton elastic scattering at high energies: Theory, phenomenology, and experiment

    SciTech Connect

    Wu, Tai Tsun.

    1990-01-01

    This is a brief review of the progress in the understanding, during the past twenty years, of hadronic elastic scattering near the forward direction at high energies. On the basis of quantum gauge field theories, the Pomeron is found to be a branch cut above 1. Using the physical picture that this result implies, phenomenology for proton-proton and antiproton-proton elastic scattering is constructed. Two noteworthy features are that, at high energies, both the total cross section and the ratio of the integrated elastic cross section to the total cross section to the total cross section are increasing functions of the center-of-mass energy. Detailed predictions are given for the elastic differential cross sections, Coulomb interference and the ratios of the real to imaginary parts of the forward amplitudes. These predictions have been extensively and accurately confirmed by experiments, and have also been given both for future experiments on existing accelerators and for experiments on future accelerators. 14 refs., 2 figs.

  12. Proton-proton and proton-antiproton elastic scattering at high energies: Theory, phenomenology, and experiment

    SciTech Connect

    Wu, Tai Tsun

    1990-12-31

    This is a brief review of the progress in the understanding, during the past twenty years, of hadronic elastic scattering near the forward direction at high energies. On the basis of quantum gauge field theories, the Pomeron is found to be a branch cut above 1. Using the physical picture that this result implies, phenomenology for proton-proton and antiproton-proton elastic scattering is constructed. Two noteworthy features are that, at high energies, both the total cross section and the ratio of the integrated elastic cross section to the total cross section to the total cross section are increasing functions of the center-of-mass energy. Detailed predictions are given for the elastic differential cross sections, Coulomb interference and the ratios of the real to imaginary parts of the forward amplitudes. These predictions have been extensively and accurately confirmed by experiments, and have also been given both for future experiments on existing accelerators and for experiments on future accelerators. 14 refs., 2 figs.

  13. Parity Violation in Forward Angle Elastic Electron-Proton Scattering

    SciTech Connect

    Miller, IV, Grady Wilson

    2001-01-01

    We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton at Jefferson Laboratory. The kinematic point ({theta}_lab = 12.3 deg. and (Q^2) = 0.48 (GeV/c)^2) is chosen to provide sensitivity to the strange electric form factor G^s_E. A 3.36 GeV beam of longitudinally polarized electrons was scattered from protons in a liquid hydrogen target. The scattered flux was detected by a pair of spectrometers which focussed the elastically-scattered electrons onto total-absorption detectors. The detector signals were integrated and digitized by a custom data acquisition system. A feedback system reduced systematic errors by controlling helicity-correlated beam intensity differences at the sub-ppm (part per million) level. The experimental result, A = 14.5 +/- 2.0 (stat) +/- 1.1 (syst) ppm, is consistent with the electroweak Standard Model with no additional contributions from strange quarks. In particular, the measurement implies G^S_E + 0.39 G^s_M = 0.023 +/- 0.040 +/- 0.026 ({delta}G^n_E), where the last uncertainty is due to the estimated uncertainty in the neutron electric form factor G^n_E . This result represents the first experimental constraint of the strange electric form factor.

  14. The recoil proton polarization in. pi. p elastic scattering

    SciTech Connect

    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.

  15. Elastic proton-deuteron scattering at intermediate energies

    SciTech Connect

    Ramazani-Moghaddam-Arani, A.; Amir-Ahmadi, H. R.; Biegun, A.; Eslami-Kalantari, M.; Joulaeizadeh, L.; Kalantar-Nayestanaki, N.; Mardanpour, H.; Messchendorp, J. G.; Moeini, H.; Shende, S. V.; Bacher, A. D.; Bailey, C. D.; Stephenson, E. J.; Gasparic, I.; Kistryn, St.; Sworst, R.; Kozela, A.; Micherdzinska, A. M.; Stephan, E.

    2008-07-15

    Observables in elastic proton-deuteron scattering are sensitive probes of the nucleon-nucleon interaction and three-nucleon force effects. The present experimental database for this reaction is large, but contains a large discrepancy between data sets for the differential cross section taken at 135 MeV/nucleon by two experimental research groups. This article reviews the background of this problem and presents new data taken at Kernfysisch Versneller Instituute (KVI). Differential cross sections and analyzing powers for the {sup 2}H(p-vector,d)p and {sup 1}H(d-vector,d)p reactions at 135 MeV/nucleon and 65 MeV/nucleon, respectively, have been measured. The differential cross-section data differ significantly from previous measurements and consistently follow the energy dependence as expected from an interpolation of published data taken over a large range at intermediate energies.

  16. Small angle elastic scattering of protons off of spinless nuclei

    SciTech Connect

    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.

  17. Proton form factors and two-photon exchange in elastic electron-proton scattering

    SciTech Connect

    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.

  18. ELRADGEN: Monte Carlo generator for radiative events in elastic electron-proton scattering

    SciTech Connect

    A.V. Afanasev; I. Akushevich; A. Ilyichev; B. Niczyporuk

    2003-08-01

    We discuss the theoretical approach and practical algorithms for simulation of radiative events in elastic ep-scattering. A new Monte Carlo generator for real photon emission events in the process of elastic electron-proton scattering is presented. We perform a few consistency checks and present numerical results.

  19. Studying the proton 'radius' puzzle with μp elastic scattering

    SciTech Connect

    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.

  20. Spin dependence in polarized proton-proton elastic scattering at RHIC

    NASA Astrophysics Data System (ADS)

    Plyku, Donika

    The STAR (Solenoidal Tracker At RHIC - Relativistic Heavy Ion Collider) experiment is equipped with Roman Pots, insertion devices that allow detectors to be moved close to the beam for the measurement of high energy protons scattered at very small angles. This setup, together with the unique capability of RHIC to collide spin-polarized proton beams, allows STAR to study both the dynamics and the spin-dependence of the proton-proton ( pp) elastic scattering process. Silicon strip detectors, installed inside the Roman Pots, measure tracks of protons scattered diffractively at very small angles. In a dedicated run with special beam optics during the 2009 RHIC run, the collaboration collected about 20 million elastic events with transversely polarized proton beams at the center of mass energy s = 200 GeV and four momentum transfer squared (t) range of 0.003 ≤ |t| ≤ 0.035 (GeV/c) 2, where, due to the Coulomb Nuclear Interference (CNI), a measurable single spin asymmetry arises. While the electromagnetic interaction can be determined in QED, the description of the hadronic interaction at small -t scattering requires the use of nonperturbative techniques in QCD, and, phenomenological models, rather than pQCD, are used to describe the exchange mechanism. High energy diffractive scattering at small-t is dominated by the Pomeron exchange, treated in pQCD as a color singlet combination of two gluons carrying quantum numbers of the vacuum (JPC = 0++). In this dissertation, I report on a high precision measurement of the transverse single spin asymmetry A N at s = 200 GeV in pp elastic scattering at RHIC. The measured AN and its t-dependence are consistent with the absence of a hadronic spin-flip amplitude. The major contribution to the uncertainty in AN comes from the uncertainty in the beam polarization measurement. The presented results provide a precise measurement in the non-perturbative QCD regime, where experimental data are indispensable, and, a significant

  1. Measuring the Weak Charge of the Proton via Elastic Electron-Proton Scattering

    SciTech Connect

    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 QpW 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 pW = 0.064 ± 0.012, in good agreement with the Standard Model prediction of pW(SM) = 0.0708 ± 0.0003[2].

  2. On the possibility for precision measurements of differential cross sections for elastic proton-proton scattering at the Protvino accelerator

    NASA Astrophysics Data System (ADS)

    Denisov, S. P.; Kozelov, A. V.; Petrov, V. A.

    2016-03-01

    Elastic-scattering data were analyzed, and it was concluded on the basis of this analysis that precisionmeasurements of differential cross sections for elastic proton-proton scattering at the accelerator of the Institute for High Energy Physics (IHEP, Protvino, Russia) over a broad momentum-transfer range are of importance and topical interest. The layout of the respective experimental facility detecting the scattered particle and recoil proton and possessing a high momentum-transfer resolution was examined along with the equipment constituting this facility. The facility in question is able to record up to a billion events of elastic proton-proton scattering per IHEP accelerator run (20 days). Other lines of physics research with this facility are briefly discussed.

  3. Two-photon exchange correction to muon-proton elastic scattering at low momentum transfer

    NASA Astrophysics Data System (ADS)

    Tomalak, Oleksandr; Vanderhaeghen, Marc

    2016-03-01

    We evaluate the two-photon exchange (TPE) correction to the muon-proton elastic scattering at small momentum transfer. Besides the elastic (nucleon) intermediate state contribution, which is calculated exactly, we account for the inelastic intermediate states by expressing the TPE process approximately through the forward doubly virtual Compton scattering. The input in our evaluation is given by the unpolarized proton structure functions and by one subtraction function. For the latter, we provide an explicit evaluation based on a Regge fit of high-energy proton structure function data. It is found that, for the kinematics of the forthcoming muon-proton elastic scattering data of the MUSE experiment, the elastic TPE contribution dominates, and the size of the inelastic TPE contributions is within the anticipated error of the forthcoming data.

  4. Normal Spin Asymmetries in Elastic Electron-Proton Scattering

    SciTech Connect

    M. Gorchtein; P.A.M. Guichon; M. Vanderhaeghen

    2004-10-01

    We discuss the two-photon exchange contribution to observables which involve lepton helicity flip in elastic lepton-nucleon scattering. This contribution is accessed through the single spin asymmetry for a lepton beam polarized normal to the scattering plane. We estimate this beam normal spin asymmetry at large momentum transfer using a parton model and we express the corresponding amplitude in terms of generalized parton distributions. We further discuss this observable in the quasi-RCS kinematics which may be dominant at certain kinematical conditions and find it to be governed by the photon helicity-flip RCS amplitudes.

  5. Spin observables in neutron-proton elastic scattering

    SciTech Connect

    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.

  6. Measurement of the absolute differential cross section of proton-proton elastic scattering at small angles

    NASA Astrophysics Data System (ADS)

    Mchedlishvili, D.; Chiladze, D.; Dymov, S.; Bagdasarian, Z.; Barsov, S.; Gebel, R.; Gou, B.; Hartmann, M.; Kacharava, A.; Keshelashvili, I.; Khoukaz, A.; Kulessa, P.; Kulikov, A.; Lehrach, A.; Lomidze, N.; Lorentz, B.; Maier, R.; Macharashvili, G.; Merzliakov, S.; Mikirtychyants, S.; Nioradze, M.; Ohm, H.; Prasuhn, D.; Rathmann, F.; Serdyuk, V.; Schroer, D.; Shmakova, V.; Stassen, R.; Stein, H. J.; Stockhorst, H.; Strakovsky, I. I.; Ströher, H.; Tabidze, M.; Täschner, A.; Trusov, S.; Tsirkov, D.; Uzikov, Yu.; Valdau, Yu.; Wilkin, C.; Workman, R. L.; Wüstner, P.

    2016-04-01

    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. After extrapolating the differential cross sections to the forward direction, the results are broadly compatible with the predictions of forward dispersion relations.

  7. TWO-PHOTON EXCHANGE IN ELECTRON-PROTON ELASTIC SCATTERING: THEORY UPDATE

    SciTech Connect

    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.

  8. 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.

  9. Two-photon exchange in proton elastic scattering

    NASA Astrophysics Data System (ADS)

    Bernauer, Jan C.

    2015-10-01

    Recent interest in the proton electromagnetic form factors is partly motivated by the discrepancy found in the determination of the electric-to-magnetic form factor ratio using different techniques. Results from scattering experiments using the Rosenbluth technique indicate that the form factor ratio is constant as a function of Q2 while experiments employing polarization show a clear, roughly linear, decline of the ratio. A possible explanation is the typically unaccounted for contribution of hard two-photon exchange to the scattering process. Theoretical calculations show large variations, many indicating an effect of the right sign and magnitude. Direct verification was sought by experiments at VEPP-3, Jefferson Lab and by the OLYMPUS collaboration at DESY. In the talk, I will discuss the OLYMPUS experiment and the current state of experimental and theoretical results.

  10. Two-photon exchange correction in elastic unpolarized electron-proton scattering at small momentum transfer

    NASA Astrophysics Data System (ADS)

    Tomalak, O.; Vanderhaeghen, M.

    2016-01-01

    We evaluate the two-photon exchange (TPE) correction to the unpolarized elastic electron-proton scattering at small momentum transfer Q2 . We account for the inelastic intermediate states approximating the double virtual Compton scattering by the unpolarized forward virtual Compton scattering. The unpolarized proton structure functions are used as input for the numerical evaluation of the inelastic contribution. Our calculation reproduces the leading terms in the Q2 expansion of the TPE correction and goes beyond this approximation by keeping the full Q2 dependence of the proton structure functions. In the range of small momentum transfer, our result is in good agreement with the empirical TPE fit to existing data.

  11. Determination of the proton charge radius from elastic electron-proton scattering

    NASA Astrophysics Data System (ADS)

    Horbatsch, Marko; Hessels, Eric A.

    2016-05-01

    Precisely measured electron-proton elastic scattering cross sections are reanalyzed to evaluate their strength for determining the rms charge radius (RE) of the proton. More than half of the cross sections at lowest Q2 are fit using two single-parameter form-factor models, with the first based on a dipole parametrization, and the second on a linear fit to a conformal-mapping variable. These low-Q2 fits extrapolate the slope of the form factor to Q2 = 0 and determine RE values of approximately 0.84 and 0.89 fm, respectively. Fits spanning all Q2, in which the single constants are replaced with cubic splines at larger Q2, lead to similar results for RE. We conclude that the scattering data are consistent with RE ranging from at least 0.84 to 0.89 fm, and therefore is consistent with both of the discrepant determinations of RE made using muonic and electronic hydrogen-atom spectroscopy. NSERC Canada, Canada Research Chair Program.

  12. Spin asymmetries for elastic proton scattering and the spin-dependent couplings of the Pomeron

    SciTech Connect

    Trueman, T. L.

    2008-03-01

    This paper serves as a report on the large amount of analysis done in conjunction with the polarized proton program at the Relavitistic Heavy Ion Collider at Brookhaven National Laboratory. This comprises elastic scattering data of protons on protons in colliding beam or fixed target mode and proton beams on carbon targets. In addition to providing a model for the energy dependence of the analyzing power of elastic scattering needed for proton polarimetry, it also provides some significant information about the spin dependence of dominant Regge poles. Most notably, the data indicate that the Pomeron has a significant spin-flip coupling. This allows the exploration of the double-spin flip asymmetry A{sub NN} for which some data over a wide energy range are now available, along with a concrete realization of a proposed Odderon search.

  13. Measurement and parametrization of proton elastic scattering cross sections for nitrogen

    SciTech Connect

    Radovic, I. Bogdanovic; Siketic, Z.; Jaksic, M.; Gurbich, A. F.

    2008-10-01

    The cross sections for the elastic scattering of protons from natural nitrogen at non-Rutherford scattering energies were measured at three laboratory scattering angles: 118 deg., 150 deg., and 165 deg. The experimental data were parametrized in the framework of nuclear physics models. A benchmark experiment was performed in order to prove that the excitation functions obtained in the present work can be used to adequately simulate the yield from a thick target containing nitrogen.

  14. Transverse Spin Asymmetries in the CNI Region of Elastic Proton-Proton Scattering at s=200 GeV

    NASA Astrophysics Data System (ADS)

    Svirida, Dmitry

    2016-02-01

    Precise measurements of transverse spin asymmetries in proton-proton elastic scattering at very small values of four-momentum transfer squared, t, have been performed using the Relativistic Heavy Ion Collider (RHIC) polarized proton beams. The measurements of both single and double spin asymmetries were made at the center-of-mass energy s = 200 GeV and in the region 0.003 ≤|t|≤ 0.035 (GeV/c)2, which was accessed using Roman Pot devices incorporated into the STAR experimental setup. The obtained set of asymmetries is sensitive to the poorly known hadronic contribution to the spin-flip amplitudes and provide significant constraints for the theoretical descriptions of the reaction mechanism of proton-proton elastic scattering at high energies.

  15. Benchmark measurements of non-Rutherford proton elastic scattering cross section for boron

    NASA Astrophysics Data System (ADS)

    Chiari, M.; Bianconi, M.; Bogdanović Radović, I.; Mayer, M.

    2015-01-01

    In the literature several elastic scattering cross-sections data sets are available for protons on 10B and 11B at energies and scattering angles suitable for elastic backscattering spectrometry (EBS) analysis. However, agreement between these different data sets is generally poor, with systematic differences up to 20%, well beyond the stated absolute uncertainties. To resolve the conflict between the different data sets in the absence of the evaluated cross-section data, a benchmark experiment was performed. Proton backscattering spectra were obtained with a thick uniform B4C target at beam energies in the range of 2.0-4.0 MeV and at different scattering angles, followed by a standard direct simulation with the SIMNRA code using the available experimental cross-section data. As a result, recommendation on the most appropriate data set to be used in proton EBS analysis of boron is given.

  16. Single-spin asymmetries from two-photon exchange in elastic electron proton scattering

    SciTech Connect

    A.V. Afanasev; N.P. Merenkov

    2005-02-01

    The parity-conserving single-spin beam asymmetry of elastic electron-proton scattering is induced by an absorptive part of the two-photon exchange amplitude. We demonstrate that this asymmetry has logarithmic and double-logarithmic enhancement due to contributions of hard collinear quasi-real photons. An optical theorem is used to evaluate the asymmetry in terms of the total photoproduction cross section on the proton.

  17. Mechanism of elastic and inelastic proton scattering on a {sup 15}C nucleus in diffraction theory

    SciTech Connect

    Ibraeva, E. T.; Zhusupov, M. A.; Imambekov, O.

    2012-11-15

    The amplitudes for elastic and inelastic proton scattering on the neutron-rich nucleus {sup 15}C (to its J{sup {pi}} = 5/2{sup +} level in the latter case) in inverse kinematics were calculated within Glauber diffraction theory. First- and second-order terms were taken into account in the multiple-scattering operator. The {sup 15}C wave function in the multiparticle shell model was used. This made it possible to calculate not only respective differential cross sections but also the contribution of proton scattering on nucleons occurring in different shells. The differential cross sections for elastic and inelastic scattering were calculated at the energies of 0.2, 0.6, and 1 GeV per nucleon.

  18. Modeling proton and alpha elastic scattering in liquid water in Geant4-DNA

    NASA Astrophysics Data System (ADS)

    Tran, H. N.; El Bitar, Z.; Champion, C.; Karamitros, M.; Bernal, M. A.; Francis, Z.; Ivantchenko, V.; Lee, S. B.; Shin, J. I.; Incerti, S.

    2015-01-01

    Elastic scattering of protons and alpha (α) particles by water molecules cannot be neglected at low incident energies. However, this physical process is currently not available in the "Geant4-DNA" extension of the Geant4 Monte Carlo simulation toolkit. In this work, we report on theoretical differential and integral cross sections of the elastic scattering process for 100 eV-1 MeV incident protons and for 100 eV-10 MeV incident α particles in liquid water. The calculations are performed within the classical framework described by Everhart et al., Ziegler et al. and by the ICRU 49 Report. Then, we propose an implementation of the corresponding classes into the Geant4-DNA toolkit for modeling the elastic scattering of protons and α particles. Stopping powers as well as ranges are also reported. Then, it clearly appears that the account of the elastic scattering process in the slowing-down of the charged particle improves the agreement with the existing data in particular with the ICRU recommendations.

  19. Measurements of proton-proton and proton-antiproton elastic scattering at the European Center for Nuclear Research Intersecting Storage Rings

    NASA Astrophysics Data System (ADS)

    Amos, N. A.

    Proton-proton and proton-anitproton elastic scattering were measured at the CERN Intersecting Storage rings. Using the optical theorem, the total nuclear cross sections was extracted for these collisions. By measuring the interference between the Coulomb amplitude and the nuclear amplitude rho, the ratio of the real part to the imaginary part of the forward nuclear elastic scattering amplitude was found. Further, the nuclear slope parameter was extracted in the forward direction. The elastic scattering measurements were made at small scattering angles (approx. 1 milliradian), demanding that the detectors be placed close to the beams. Normalization of the data was performed by two methods: Van der Meer calibrations were performed on sets of luminosity monitor counters, the known Coulomb differential scattering cross section fixed the normalization scale.

  20. 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.

  1. Structure of light neutron-rich nuclei and mechanism of elastic proton scattering

    SciTech Connect

    Ibraeva, E. T.; Zhusupov, M. A.; Imambekov, O.

    2011-11-15

    Differential cross sections for elastic p{sup 6}He, p{sup 8}Li, and p{sup 9}Li scattering at two energies of 70 and 700 MeV per nucleon were calculated within the Glauber theory of multiple diffractive scattering. Threeparticle wave functions ({alpha}-n-n for {sup 6}He, {alpha}-t-n for {sup 8}Li, and {sup 7}Li-n-n for {sup 9}Li) were used for realistic potentials of intercluster interactions. The sensitivity of elastic scattering to proton-nucleus interaction and to the structure of nuclei was explored. In particular, the dependence of the differential cross section on the contribution of higher order collisions, on scattering on the core and peripheral nucleons, and on the contribution of small wave-function components and their asymptotic behavior was determined. A comparison with available experimental data and with the results of calculations within different formalisms was performed.

  2. A predictive theory for elastic scattering and recoil of protons from 4He

    DOE PAGESBeta

    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

  3. Predictive theory for elastic scattering and recoil of protons from 4He

    NASA Astrophysics Data System (ADS)

    Hupin, Guillaume; Quaglioni, Sofia; Navrátil, Petr

    2014-12-01

    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 Schrödinger 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. 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.

  4. A predictive theory for elastic scattering and recoil of protons from 4He

    SciTech Connect

    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 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.

  5. Two-Photon Exchange in Elastic Electron-Proton Scattering: A QCD Factorization Approach

    SciTech Connect

    Kivel, Nikolai; Vanderhaeghen, Marc

    2009-08-28

    We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer Q{sup 2}. It is shown that the leading two-photon exchange amplitude behaves as 1/Q{sup 4}, and can be expressed in a model independent way in terms of the leading twist nucleon distribution amplitudes. Using several models for the nucleon distribution amplitudes, we provide estimates for existing data and for ongoing experiments.

  6. Elastic proton scattering on tritium below the n-{sup 3}He threshold

    SciTech Connect

    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.

  7. Collinear Photon Exchange in the Beam Normal Polarization Asymmetry of Elastic Electron-Proton Scattering

    SciTech Connect

    Andrei Afanasev; N.P. Merenkov

    2004-07-01

    The parity-conserving single-spin beam asymmetry of elastic electron-proton scattering is induced by an absorptive part of the two-photon exchange amplitude. We demonstrate that this asymmetry has logarithmic and double-logarithmic enhancement due to contributions of hard collinear quasi-real photons. An optical theorem is used to evaluate the asymmetry in terms of the total photoproduction cross section on the proton, predicting its magnitude at 20-30 parts per million for high electron beam energies and small scattering angles. At fixed 4-momentum transfers, the asymmetry is rising logarithmically with increasing electron beam energy, following the high-energy diffractive behavior of total photoproduction cross section on the proton.

  8. Large Logarithms in the Beam Normal Spin Asymmetry of Elastic Electron--Proton Scattering

    SciTech Connect

    Andrei Afanasev; Mykola Merenkov

    2004-06-01

    We study a parity-conserving single-spin beam asymmetry of elastic electron-proton scattering induced by an absorptive part of the two-photon exchange amplitude. It is demonstrated that excitation of inelastic hadronic intermediate states by the consecutive exchange of two photons leads to logarithmic and double-logarithmic enhancement due to contributions of hard collinear quasi-real photons. The asymmetry at small electron scattering angles is expressed in terms of the total photoproduction cross section on the proton, and is predicted to reach the magnitude of 20-30 parts per million. At these conditions and fixed 4-momentum transfers, the asymmetry is rising logarithmically with increasing electron beam energy, following the high-energy diffractive behavior of total photoproduction cross section on the proton.

  9. 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.

  10. Dispersion Relations for Meson-Proton and Proton-Proton Forward Elastic Scattering

    NASA Astrophysics Data System (ADS)

    Alkin, A.; Cudell, J. R.; Martynov, E.

    2012-07-01

    An analysis of the data on forward {pp, bar pp, π^{±}p} and {K^{±}p} scattering is performed making use of the single- and double-subtraction integral and comparing with derivative dispersion relations for amplitudes. Various pomeron and odderon models for the total cross sections are considered and compared. The real part of the amplitude is calculated via dispersion relations. It is shown that the integral dispersion relations lead to a better description of the data for {sqrt{s} > 5 GeV}. Predictions of the considered models for the TOTEM experiment at LHC energies are given.

  11. Elastic Proton Scattering of Medium Mass Nuclei from Coupled-Cluster Theory

    SciTech Connect

    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.

  12. Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering

    SciTech Connect

    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.

  13. Investigation of the nuclear matter distribution of 56Ni by elastic proton scattering in inverse kinematics

    NASA Astrophysics Data System (ADS)

    von Schmid, M.; Bagchi, S.; Bönig, S.; Csatlós, M.; Dillmann, I.; Dimopoulou, C.; Egelhof, P.; Eremin, V.; Furuno, T.; Geissel, H.; Gernhäuser, R.; Harakeh, M. N.; Hartig, A.-L.; Ilieva, S.; Kalantar-Nayestanaki, N.; Kiselev, O.; Kollmus, H.; Kozhuharov, C.; Krasznahorkay, A.; Kröll, T.; Kuilman, M.; Litvinov, S.; Litvinov, Yu A.; Mahjour-Shafiei, M.; Mutterer, M.; Nagae, D.; Najafi, M. A.; Nociforo, C.; Nolden, F.; Popp, U.; Rigollet, C.; Roy, S.; Scheidenberger, C.; Steck, M.; Streicher, B.; Stuhl, L.; Thürauf, M.; Uesaka, T.; Weick, H.; Winfield, J. S.; Winters, D.; Woods, P. J.; Yamaguchi, T.; Yue, K.; Zamora, J. C.; Zenihiro, J.; the EXL Collaboration

    2015-11-01

    We have measured the nuclear-matter distribution of the doubly-magic N = Z nucleus 56Ni by investigating elastic proton scattering in inverse kinematics. The radioactive beam of 56Ni was injected and stored in the experimental storage ring (ESR, GSI) and interacted with an internal hydrogen gas-jet target. The high revolution frequency of the ions in the ring enabled a high luminosity, despite the low density of the target being used. This way, measurements at very low momentum transfers became possible. By measuring the energy and the scattering angle of the recoiling protons, we were able to separate the elastic reaction channel from inelastic scattering to the first excited {2}+ state of 56Ni and deduced the differential cross section of 56Ni {(p,p)}56 Ni. The data were analyzed within the framework of the Glauber multiple-scattering theory in order to extract the nuclear-matter radius and radial matter distribution of 56Ni. Parameterizing the matter distribution with the phenomenological Symmetrized Fermi distribution, a preliminary value of 3.5 fm for the rms matter radius was deduced. This experiment was part of an EXL (EXotic nuclei studied in Light-ion induced reactions at storage rings) campaign at GSI in 2012 and was the first successful investigation of nuclear reactions with a stored radioactive beam ever.

  14. Fast proton hopping detection in ice I{sub h} by quasi-elastic neutron scattering.

    SciTech Connect

    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.

  15. Fast Proton Hopping Detection in Ice Ih by Quasi-Elastic Neutron Scattering

    SciTech Connect

    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.

  16. 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.

  17. Elastic scattering of polarized protons on helium three at 800 MeV

    SciTech Connect

    Azizi, A.

    1985-07-01

    A set of spin dependent parameters and cross sections has been measured for polarized p-/sup 3/He elastic scattering over the range of q .7 to 4.2 fm/sup -1/. The experiment was done at the Los Alamos Meson Physics Facility (LAMPF) using the High Resolution Spectrometer (HRS) with a polarized proton beam at .8 GeV. The focal plane polarimeter of the HRS was used to determine the spin direction of the scattered proton. Since /sup 3/He is one of the simplest nuclei, polarized p-/sup 3/He scattering provides a very sensitive test of multiple scattering theories. The theoretical analysis was done by using two different wave functions for /sup 3/He as input to the multiple scattering theory. The theoretical calculations and experimental data together will give us useful information about nucleon-nucleon amplitudes and also help us to obtain a better understanding of the scattering process. 68 refs., 55 figs., 9 tabs.

  18. 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.

  19. Investigation of the structure of light exotic nuclei by proton elastic scattering in inverse kinematics

    SciTech Connect

    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.

  20. Investigation of the structure of light exotic nuclei by proton elastic scattering in inverse kinematics

    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.

  1. Measurements of Proton-Proton and Proton-Antiproton Elastic Scattering at the European Center for Nuclear Research Intersecting Storage Rings.

    NASA Astrophysics Data System (ADS)

    Amos, Norman Alexander

    1985-12-01

    We have measured proton-proton and proton-antiproton elastic scattering at the CERN Intersecting Storage Rings. Using the optical theorem, we have extracted the total nuclear cross sections for these collisions. By measuring the interference between the Coulomb amplitude and the nuclear amplitude we have found (rho), the ratio of the real part to the imaginary part of the forward nuclear elastic scattering amplitude. Further, we have extracted the nuclear slope parameter in the forward direction. The elastic scattering measurements were made at small scattering angles ((TURN)1 milliradian), demanding that the detectors be placed close to the beams. Access to the interior of the ISR beam pipe was afforded by using reentrant cavities in the beam pipe, called "Roman Pots". The detectors consisted of two conjugate pairs of scintillator hodoscopes placed above and below the beams. Each detector consisted of a front plane of 24 strips of 2 mm scintillator which measured polar scattering angles, seven strips of 4 mm scintillator which measured azimuthal angles, and a trigger counter 48 x 28 mm('2). Normalization of the data was performed by two methods: (1) Van der Meer calibrations were performed on sets of luminosity monitor counters, (2) the known Coulomb differential scattering cross section fixed the normalization scale. For proton-proton interactions, the total nuclear cross sections measured were 39.95 (+OR-) 0.30 mb and 42.19 (+OR-) 0.19 mb for center-of-mass energies SQRT.(s) = 30.6 GeV and 52.8 GeV, respectively. The measured values of (rho) were 0.035 (+OR-) 0.009 and 0.071 (+OR-) 0.010. For proton-antiproton interactions, the cross sections found were 41.10 (+OR-) 0.40 mb and 43.34 (+OR-) 0.43 mb, respectively, and the (rho) values were 0.088 (+OR-) 0.025 and 0.066 (+OR-) 0.022.

  2. Measurement of the absolute differential cross section of proton–proton elastic scattering at small angles

    DOE PAGESBeta

    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

  3. Nuclear Proton-proton Elastic Scattering via the Trojan Horse Method

    SciTech Connect

    Tumino, A.; Spitaleri, C.; Rapisarda, G. G.; Cherubini, S.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Romano, S.; Sergi, M. L.; Mukhamedzhanov, A.; Campajola, L.; Elekes, Z.; Fueloep, Zs.; Gyuerky, G.; Kiss, G. G.; Somorjai, E.; Gialanella, L.

    2009-08-26

    We present here an important test of the main feature of the Trojan Horse Method (THM), namely the suppression of Coulomb effects in the entrance channel due to off-energy-shell effects. This is done by measuring the THM p--p elastic scattering via the p+d{yields}p+p+n reaction at 4.7 and 5 MeV, corresponding to a p--p relative energy ranging from 80 to 670 keV. In contrast to the on-energy-shell (OES) case, the extracted p-p cross section does not exhibit the Coulomb-nuclear interference minimum due to the suppression of the Coulomb amplitude. This is confirmed by the half-off-energy shell (HOES) calculations and strengthened by the agreement with the calculated OES nuclear cross sections.

  4. 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.

  5. Virtual coupling potential for elastic scattering of 10,11Be on proton and carbon targets

    NASA Astrophysics Data System (ADS)

    Lapoux, V.; Alamanos, N.; Auger, F.; Blumenfeld, Y.; Casandjian, J.-M.; Chartier, M.; Cortina-Gil, M. D.; Fékou-Youmbi, V.; Gillibert, A.; Cormick, M. Mac; Maréchal, F.; Marie, F.; Mittig, W.; de Oliveira Santos, F.; Orr, N. A.; Ostrowski, A. N.; Ottini-Hustache, S.; Roussel-Chomaz, P.; Scarpaci, J.-A.; Sida, J.-L.; Suomijärvi, T.; Winfield, J. S.

    2008-01-01

    The 10,11Be(p, p) and (12C, 12C) reactions were analyzed to determine the influence of the weak binding energies of exotic nuclei on their interaction potential. The elastic cross sections were measured at GANIL in inverse kinematics using radioactive 10,11Be beams produced at energies of 39.1A and 38.4 A MeV. The elastic proton scattering data were analyzed within the framework of the microscopic Jeukenne-Lejeune-Mahaux (JLM) nucleon-nucleus potential. The angular distributions are found to be best reproduced by reducing the real part of the microscopic optical potential, as a consequence of the coupling to the continuum. These effects modify deeply the elastic potential. Including the Virtual Coupling Potential (VCP), we show the ability of the general optical potentials to reproduce the data for scattering of unstable nuclei, using realistic densities. Finally, the concepts needed to develop a more general and microscopic approach of the VCP are discussed.

  6. Measurements of proton-proton elastic scattering and total cross-section at the LHC by TOTEM

    NASA Astrophysics Data System (ADS)

    Deile, M.; Totem Collaboration

    2013-04-01

    The TOTEM experiment at the LHC has extended the measurement of the differential cross-section for elastic proton-proton scattering at √s = 7TeV to four-momentum transfers |t| as low as 5×10-3 GeV2. The new data were collected in different dedicated runs with a special beam optics (β* = 90m) and Roman Pot detectors placed as close as 4.8 times the transverse beam size from the outgoing beams. In addition, the accompanying inelastic rates were recorded with the forward telescopes T1 and T2 for 3.1 < |η| < 6.5. Thus the first measurement of the total protonproton cross-section with the luminosity-independent method based on the optical theorem could be performed. Alternatively, using the CMS luminosity measurement as an input, two additional total crosssection determinations with different systematic dependences were obtained: (a) as the direct sum of the elastic and inelastic cross-sections, and (b) calculated from only the elastic cross-section extrapolated to t = 0, as published previously [1] for an earlier data set. The results from all methods and data sets agree very well within their uncertainties.

  7. Measurements on Small Angle Elastic Scattering from Proton-Proton and Proton-Antiproton Collisions at the ISR.

    NASA Astrophysics Data System (ADS)

    Shukla, Shekhar

    Experiment R211 was performed at the Intersecting Storage Rings (ISR) of the European Center for Nuclear Research (CERN), Geneva, Switzerland. The aim was to measure, for pp and pp scattering at high energy, the three quantities: (1) the total nuclear cross section, (sigma)(,n), (2) the nuclear slope parameter, b, that describes the dependence of the differential elastic cross section on the 4-momentum transfer, t, for small (VBAR)t(VBAR), and (3) the ratio, (rho), of the real to the imaginary part of the forward nuclear elastic scattering amplitude. These quantities were deduced from differential elastic scattering cross sections measured in the near forward direction (down to (VBAR)t(VBAR) = .0003(GeV/c)('2) at SQRT.(s) = 23.5 GeV). The measurements were made for pp scattering at SQRT.(s) = 23.5 GeV, 30.5 GeV, 52.8 GeV and 62.5 GeV and pp scattering at SQRT.(s) = 30.5 GeV, 52.8 GeV and 62.5 GeV. The scattering was produced with two beams colliding at an angle of 14.7(DEGREES). Detectors consisting of strips of scintillators recorded the positions of the elastically scattered particles in the near forward direction. Another set of scintillation counters, calibrated using the van der Meer method, measured the luminosity. The optical theorem was used to obtain (sigma)(,n) from the differential cross section in the forward direction. Where available, the differential cross sections in the (VBAR)t(VBAR) range where the Coulomb and nuclear interaction were of comparable strength, served to determine the value of (rho). Again, if available, the measurements at higher values of (VBAR)t(VBAR), where the nuclear scattering dominated, were used to find the value of the slope parameter, b. The following quantities were measured: (i) (sigma)(,n) and (rho) at SQRT.(s) = 23.5 GeV and SQRT.(s) = 30.5 GeV, (ii) (sigma)(,n), (rho) and b at SQRT.(s) = 52.8 GeV and (iii) (sigma)(,n) and b at SQRT.(s) = 62.5 GeV. The total cross section for both pp and pp scattering is seen to rise

  8. Elastic scattering and breakup of 11Be on protons at 26.9 A MeV

    NASA Astrophysics Data System (ADS)

    Chen, J.; Lou, J. L.; Ye, Y. L.; Li, Z. H.; Ge, Y. C.; Li, Q. T.; Li, J.; Jiang, W.; Sun, Y. L.; Zang, H. L.; Aoi, N.; Ideguchi, E.; Ong, H. J.; Ayyad, Y.; Hatanaka, K.; Tran, D. T.; Yamamoto, T.; Tanaka, M.; Suzuki, T.; Tho, N. T.; Rangel, J.; Moro, A. M.; Pang, D. Y.; Lee, J.; Wu, J.; Liu, H. N.; Wen, C.

    2016-03-01

    The elastic scattering and breakup of the halo nucleus 11Be on protons at an incident energy of 26.9 A MeV have been measured. The 11Be+p elastic scattering cross sections at various energies, including the present one, are systematically analyzed with the Chapel Hill 89 (CH89) and Koning-Delaroche (KD) global optical model potentials (OMPs), and the corresponding normalization factors are obtained. An extended version of the continuum-discretized coupled-channels (XCDCC) formalism, including dynamic core excitation effects, is applied to analyze the elastic scattering and breakup data. It is found that the core excitation plays a moderate role in the elastic scattering and breakup reaction of the halo nucleus 11Be, being consistent with previous results at higher energies.

  9. Proton-proton elastic scattering at the LHC energy of \\chem{\\sqrt{s} = 7\\,TeV}

    NASA Astrophysics Data System (ADS)

    TOTEM Collaboration; Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bozzo, M.; Brücken, E.; Buzzo, A.; Cafagna, F. S.; Calicchio, M.; Catanesi, M. G.; Covault, C.; Csanád, M.; Csörgö, T.; Deile, M.; Dimovasili, E.; Doubek, M.; Eggert, K.; Eremin, V.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Janda, M.; Kašpar, J.; Kopal, J.; Kundrát, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lokajíček, M.; Lo Vetere, M.; Rodríguez, F. Lucas; Macrí, M.; Magaletti, L.; Magazzù, G.; Mercadante, A.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Noschis, E.; Novák, T.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Perrot, A.-L.; Palazzi, P.; Pedreschi, E.; Petäjäjärvi, J.; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Santroni, A.; Scribano, A.; Sette, G.; Snoeys, W.; Spinella, F.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Vitek, M.; Welti, J.; Whitmore, J.

    2011-08-01

    Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at \\sqrt{s} = 7\\,TeV in dedicated runs with the Roman Pot detectors placed as close as seven times the transverse beam size (σbeam) from the outgoing beams. After careful study of the accelerator optics and the detector alignment, |t|, the square of four-momentum transferred in the elastic scattering process, has been determined with an uncertainty of \\delta t = 0.1\\,\\rm{GeV} \\sqrt{\\vert t\\vert } . In this letter, first results of the differential cross-section are presented covering a |t|-range from 0.36 to 2.5 GeV2. The differential cross-section in the range 0.36 < |t| < 0.47 GeV2 is described by an exponential with a slope parameter B = (23.6 ± 0.5stat ± 0.4syst) GeV-2, followed by a significant diffractive minimum at |t| = (0.53 ± 0.01stat ± 0.01syst) GeV2. For |t|-values larger than ~1.5 GeV2, the cross-section exhibits a power law behaviour with an exponent of -7.8 ± 0.3stat ± 0.1syst. When compared to predictions based on the different available models, the data show a strong discriminative power despite the small t-range covered.

  10. Condensate-enclosed chiral-bag model of the proton and pp elastic scattering at LHC 13 TeV

    NASA Astrophysics Data System (ADS)

    Islam, M. M.; Luddy, R. J.

    2015-11-01

    Our investigation of high energy pp and p¯p elastic scattering over the last ten years has led us to consider that the proton has three regions: (i) an outer region consisting of a quark-antiquark (qq¯) condensate ground state (also described as quark-antiquark outer cloud), (ii) an inner shell of topological (geometrical) baryonic charge of size ˜ 0.44 fm, and (iii) a core of size ˜ 0.2 fm, where the three valence quarks of a proton with baryonic charges are confined. The proton structure that has emerged leads to four main elastic scattering processes in pp scattering. The first process (which gives rise to diffraction scattering) is described by a profile function. The second process involves multiple ω-exchanges. The third process in pp scattering is quark-quark scattering via gluon-gluon interaction. The fourth process — which appears for the first time in our investigation of pp scattering — is a glancing collision at the boundary of a proton with that of the other proton. To describe quantitatively the four processes, their parameters have to be determined. For this purpose, we investigate: (i) pp 7 TeV dσ/dt measured by the TOTEM Collaboration and (ii) p¯p 1.96 TeV dσ/dt measured by the D0 Collaboration. Once the parameters are satisfactorily obtained, we calculate pp dσ/dt at 7 TeV and compare with the TOTEM data. We also calculate p¯p dσ/dt at 1.96 TeV and compare with the D0 data. We then predict pp elastic dσ/dt at 13 TeV which will soon be measured at LHC by the TOTEM Collaboration. This measurement will establish how well we have predicted the 13 TeV dσ/dt and determined the structure of the proton.

  11. Transverse Beam Spin Asymmetries at Backward Angles in Elastic Electron-Proton and Quasielastic Electron-Deuteron Scattering

    NASA Astrophysics Data System (ADS)

    Androić, D.; Armstrong, D. S.; Arvieux, J.; Bailey, S. L.; Beck, D. H.; Beise, E. J.; Benesch, J.; Benmokhtar, F.; Bimbot, L.; Birchall, J.; Bosted, P.; Breuer, H.; Capuano, C. L.; Chao, Y.-C.; Coppens, A.; Davis, C. A.; Ellis, C.; Flores, G.; Franklin, G.; Furget, C.; Gaskell, D.; Gericke, M. T. W.; Grames, J.; Guillard, G.; Hansknecht, J.; Horn, T.; Jones, M. K.; King, P. M.; Korsch, W.; Kox, S.; Lee, L.; Liu, J.; Lung, A.; Mammei, J.; Martin, J. W.; McKeown, R. D.; Micherdzinska, A.; Mihovilovic, M.; Mkrtchyan, H.; Muether, M.; Page, S. A.; Papavassiliou, V.; Pate, S. F.; Phillips, S. K.; Pillot, P.; Pitt, M. L.; Poelker, M.; Quinn, B.; Ramsay, W. D.; Real, J.-S.; Roche, J.; Roos, P.; Schaub, J.; Seva, T.; Simicevic, N.; Smith, G. R.; Spayde, D. T.; Stutzman, M.; Suleiman, R.; Tadevosyan, V.; van Oers, W. T. H.; Versteegen, M.; Voutier, E.; Vulcan, W.; Wells, S. P.; Williamson, S. E.; Wood, S. A.; Pasquini, B.; Vanderhaeghen, M.

    2011-07-01

    We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasielastic scattering on the deuteron, at backward angles (lab scattering angle of 108°) for Q2=0.22GeV2/c2 and 0.63GeV2/c2 at beam energies of 362 and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single-photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (πN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasistatic deuterium approximation, and is also in agreement with theory.

  12. Transverse beam spin asymmetries at backward angles in elastic electron-proton and quasielastic electron-deuteron scattering.

    PubMed

    Androić, D; Armstrong, D S; Arvieux, J; Bailey, S L; Beck, D H; Beise, E J; Benesch, J; Benmokhtar, F; Bimbot, L; Birchall, J; Bosted, P; Breuer, H; Capuano, C L; Chao, Y-C; Coppens, A; Davis, C A; Ellis, C; Flores, G; Franklin, G; Furget, C; Gaskell, D; Gericke, M T W; Grames, J; Guillard, G; Hansknecht, J; Horn, T; Jones, M K; King, P M; Korsch, W; Kox, S; Lee, L; Liu, J; Lung, A; Mammei, J; Martin, J W; McKeown, R D; Micherdzinska, A; Mihovilovic, M; Mkrtchyan, H; Muether, M; Page, S A; Papavassiliou, V; Pate, S F; Phillips, S K; Pillot, P; Pitt, M L; Poelker, M; Quinn, B; Ramsay, W D; Real, J-S; Roche, J; Roos, P; Schaub, J; Seva, T; Simicevic, N; Smith, G R; Spayde, D T; Stutzman, M; Suleiman, R; Tadevosyan, V; van Oers, W T H; Versteegen, M; Voutier, E; Vulcan, W; Wells, S P; Williamson, S E; Wood, S A; Pasquini, B; Vanderhaeghen, M

    2011-07-01

    We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasielastic scattering on the deuteron, at backward angles (lab scattering angle of 108°) for Q² = 0.22 GeV²/c² and 0.63 GeV²/c² at beam energies of 362 and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single-photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (πN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasistatic deuterium approximation, and is also in agreement with theory. PMID:21797598

  13. Measurements of sin/sup 2/ theta/sub w/ from studies of the elastic scattering of neutrinos by protons and electrons

    SciTech Connect

    Mann, A.K.

    1986-01-01

    This talk is intended as a brief report on studies of the elastic scattering of neutrinos by protons and electrons. Measurements of the ratios of muon antineutrino and muon neutrino elastic scattering on protons, and the corresponding ratio for elastic scattering on electrons minimize systematic experimental errors, and lead directly to values of the fundamental parameter of the electroweak interaction, the Weinberg Angle, with minimal ambiguity. Accordingly, the principal motivation in carrying out these studies was the desire to obtain and compare precise values of the Weinberg Angle from both the semileptonic and leptonic reactions as still another test of the basic validity of the standard electroweak theory. 10 refs., 11 figs.

  14. Structure of low-lying states of {sup 10,11}C from proton elastic and inelastic scattering

    SciTech Connect

    Jouanne, C.; Lapoux, V.; Auger, F.; Alamanos, N.; Drouart, A.; Gillibert, A.; Lobo, G.; Musumarra, A.; Nalpas, L.; Pollacco, E.; Sida, J.-L.; Trotta, M.; Blumenfeld, Y.; Khan, E.; Suomijaervi, T.; Zerguerras, T.; Roussel-Chomaz, P.; Savajols, H.; Lagoyannis, A.; Pakou, A.

    2005-07-01

    To probe the ground state and transition densities, elastic and inelastic scattering on a proton target were measured in inverse kinematics for the unstable {sup 10}C and {sup 11}C nuclei at 45.3 and 40.6 MeV/nucleon, respectively. The detection of the recoil proton was performed by the MUST telescope array, in coincidence with a wall of scintillators for the quasiprojectile. The differential cross sections for elastic and inelastic scattering to the first excited states are compared to the optical model calculations performed within the framework of the microscopic nucleon-nucleus Jeukenne-Lejeune-Mahaux potential. Elastic scattering is sensitive to the matter-root-mean square radius found to be 2.42{+-}0.1 and 2.33{+-}0.1 fm, for {sup 10,11}C, respectively. The transition densities from cluster and mean-field models are tested, and the cluster model predicts the correct order of magnitude of cross sections for the transitions of both isotopes. Using the Bohr-Mottelson prescription, a profile for the {sup 10}C transition density from the 0{sup +} ground to the 2{sub 1}{sup +} state is deduced from the data. The corresponding neutron transition matrix element is extracted: M{sub n}=5.51{+-}1.09 fm{sup 2}.

  15. Meson exchange effects in elastic ep scattering at loop level and the electromagnetic form factors of the proton

    NASA Astrophysics Data System (ADS)

    Chen, Hong-Yu; Zhou, Hai-Qing

    2014-10-01

    A new form of two-photon exchange (TPE) effect is studied to explain the discrepancy between unpolarized and polarized experimental data in elastic ep scattering. The mechanism is based on a simple idea that apart from the usual TPE effects from box and crossed-box diagrams, the mesons may also be exchanged in elastic ep scattering by two-photon coupling at loop level. The detailed study shows such contributions to reduced unpolarized cross section (σun) and polarized observables (Pt,Pl) at fixed Q2 are only dependent on proton's electromagnetic form factors GE ,M and a new unknown universal parameter g. After combining this contribution with the usual TPE contributions from box and crossed-box diagrams, the ratio μpGE/GM extracted from the recent precise unpolarized and polarized experimental data can be described consistently.

  16. Two-Photon-Exchange and {gamma}Z-Exchange Corrections to Parity-Violating Elastic Electron-Proton Scattering

    SciTech Connect

    Zhou Haiqing; Kao Chungwen; Yang Shinnan

    2007-12-31

    Leading electroweak corrections play an important role in precision measurements of the strange form factors. We calculate the two-photon-exchange (TPE) and {gamma}Z-exchange corrections to the parity-violating asymmetry of the elastic electron-proton scattering in a simple hadronic model including the finite size of the proton. We find both can reach a few percent and are comparable in size with the current experimental measurements of strange-quark effects in the proton neutral weak current. The effect of {gamma}Z exchange is in general larger than that of TPE, especially at low momentum transfer Q{sup 2}{<=}1 GeV{sup 2}. Their combined effects on the values of G{sub E}{sup s}+G{sub M}{sup s} extracted in recent experiments can be as large as -40% in certain kinematics.

  17. Measurement of analyzing power for proton-carbon elastic scattering in the coulomb-nuclear interference region with a 22-GeV/c polarized proton beam.

    PubMed

    Tojo, J; Alekseev, I; Bai, M; Bassalleck, B; Bunce, G; Deshpande, A; Doskow, J; Eilerts, S; Fields, D E; Goto, Y; Huang, H; Hughes, V; Imai, K; Ishihara, M; Kanavets, V; Kurita, K; Kwiatkowski, K; Lewis, B; Lozowski, W; Makdisi, Y; Meyer, H-O; Morozov, B V; Nakamura, M; Przewoski, B; Rinckel, T; Roser, T; Rusek, A; Saito, N; Smith, B; Svirida, D; Syphers, M; Taketani, A; Thomas, T L; Underwood, D; Wolfe, D; Yamamoto, K; Zhu, L

    2002-07-29

    The analyzing power for proton-carbon elastic scattering in the Coulomb-nuclear interference region of momentum transfer, 9.0x10(-3)<-t<4.1x10(-2) (GeV/c)(2), was measured with a 21.7 GeV/c polarized proton beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory. The ratio of hadronic spin-flip to nonflip amplitude, r(5), was obtained from the analyzing power to be Rer(5)=0.088+/-0.058 and Imr(5)=-0.161+/-0.226. PMID:12144435

  18. Monte Carlo simulation and parameterized treatment on the effect of nuclear elastic scattering in high-energy proton radiography

    NASA Astrophysics Data System (ADS)

    Xu, Hai-Bo; Zheng, Na

    2015-07-01

    A version of Geant4 has been developed to treat high-energy proton radiography. This article presents the results of calculations simulating the effects of nuclear elastic scattering for various test step wedges. Comparisons with experimental data are also presented. The traditional expressions of the transmission should be correct if the angle distribution of the scattering is Gaussian multiple Coulomb scattering. The mean free path (which depends on the collimator angle) and the radiation length are treated as empirical parameters, according to transmission as a function of thickness obtained by simulations. The results can be used in density reconstruction, which depends on the transmission expressions. Supported by NSAF (11176001) and Science and Technology Developing Foundation of China Academy of Engineering Physics (2012A0202006)

  19. Role of elastic projectile-electron scattering in double ionization of helium by fast proton impact

    NASA Astrophysics Data System (ADS)

    Schulz, M.; Ciappina, M. F.; Kirchner, T.; Fischer, D.; Moshammer, R.; Ullrich, J.

    2009-04-01

    We present a systematic study of atomic four-body fragmentation dynamics. To this end we have measured a variety of multiple differential double ionization cross sections for 6 MeV p+He collisions. The data are compared to a first-order calculation with correlated electrons and to a simulation representing a second-order process, with some experimental results seemingly in favor of the first, others in agreement with the second approach. This apparent conflict can be resolved by accounting for elastic scattering between the projectile and one electron already promoted to the continuum through electron-electron correlation in the first-order process.

  20. Validity of the relativistic impulse approximation for elastic proton-nucleus scattering at energies lower than 200 MeV

    SciTech Connect

    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.

  1. Elastic proton scattering at intermediate energies as a probe of the He,86 nuclear matter densities

    NASA Astrophysics Data System (ADS)

    Chung, Le Xuan; Kiselev, Oleg A.; Khoa, Dao T.; Egelhof, Peter

    2015-09-01

    The Glauber model analysis of the elastic He,86+p scattering data at energies around 700 MeV/nucleon, measured in two separate experiments at GSI-Darmstadt, has been carried out using several phenomenological parametrizations of the nuclear matter density. By taking into account the new data points measured at high-momentum transfer, the nuclear matter radii of ,8He6 have been accurately determined from the Glauber model analysis of the data, with the spin-orbital interaction explicitly taken into account. The well-known geometry for the core and dineutron halo has been used with the new parametrizations of the 6He density to extract the detailed information on the structure of 6He in terms of the core and dineutron halo radii. An enhanced sensitivity of the data measured at high-momentum transfer to the core part of the 6,8He densities has been found.

  2. Direct measurements of two photon exchange on lepton-proton elastic scattering using simultaneous electron-positron beams in CLAS

    NASA Astrophysics Data System (ADS)

    Adikaram, Dasuni Kalhari

    The electric (GE) and magnetic ( GM) form factors of the proton are fundamental observables which characterize its charge and magnetization distributions. There are two methods to measure the proton form factors: the Rosenbluth separation method and the polarization transfer technique. However, the ratio of the electric and magnetic form factors measured by those methods significantly disagree at momentum transfer Q2 > 1 GeV2. The most likely explanation of this discrepancy is the inclusion of two-photon exchange (TPE) amplitude contributions to the elastic electron-proton cross section which significantly changes the extraction of GE from the Rosenbluth separation measurement. The Jefferson Lab CLAS TPE experiment determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections. The primary electron beam was used to create an intense bremsstrahlung photon beam. Some of the photons were then converted to a mixed e+/ e- beam which then interacted with a liquid hydrogen target. The e+p and e-p events were detected by the CLAS (CEBAF Large Acceptance Spectrometer). The elastic cross section ratios ((sigma( e+p)/(sigma(e -p)) were measured over a wide range of virtual photon polarization epsilon and Q2. The cross section ratios displayed a strong epsilon dependence at Q2 = 1.45 GeV2. There is no significant Q2 dependence observed at epsilon = 0.45. The results are consistent with a recent measurement at the VEPP-3 lepton storage ring in Novosibirsk and with the hadronic calculation by Blunders, Melnitchouk and Tjon. The hadronic calculation resolves the disagreement between the Rosenbluth separation and polarization transfer extractions of GE/GM at Q2 up to 2 -- 3 GeV2. Applying the GLAS TPE correction to the Rosenbluth cross section measurements significantly decreases the extracted value of GE and brings it into good agreement with the polarization transfer measurement at Q2˜1.75 GeV2. Thus, these

  3. 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.

  4. New Measurement of Parity Violation in Elastic Electron-Proton Scattering and Implications for Strange Form Factors

    SciTech Connect

    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.

  5. Test of charge symmetry in neutron-proton elastic scattering at 477 MeV

    SciTech Connect

    Abegg, R.; Bandyopadhyay, D.; Birchall, J.; Cairns, E.W.; Coombes, H.; Davis, C.A.; Davison, N.E.; Delheij, P.P.J.; Green, P.W.; Greeniaus, L.G.; Gubler, H.P.; Healy, D.C.; Lapointe, C.; Lee, W.P.; McDonald, W.J.; Miller, C.A.; Moss, G.A.; Plattner, G.R.; Poffenberger, P.R.; Ramsay, W.D.; Roy, G.; Soukup, J.; Svenne, J.P.; Tkachuk, R.; van Oers, W.T.H.; Wait, G.D.; Zhang, Y.P.

    1986-06-16

    An experiment resulting in the first measurement of the isospin-mixing, charge-symmetry violating component of the n-italic-p-italic interaction has been performed. The experiment determined the difference in the angles of the zero crossing of the neutron and proton analyzing powers A-italic/sub n-italic/ and A-italic/sub p-italic/ at 477 MeV. In terms of the laboratory scattering angle of the neutron, the measured difference t-italich-italice-italict-italica-italic/sub 0//sub n-italic/(A/sub n/)= -t-italich-italice-italict-italica-italic/sub 0//sub n-italic/(A/sub p/) = +0.13X(de +- 0.06 X(de( +- 0.03X(de) where the second error is a worst case estimate of systematic error. The resulting difference in the analyzing powers at the zero-crossing angle A-italic/sub n-italic/-A/sub p/ = +0.0037 +- 0.0017( +- 0 .0008).

  6. Measurement of proton-proton elastic scattering and total cross-section at \\chem{\\sqrt {s} = 7\\,TeV}

    NASA Astrophysics Data System (ADS)

    The TOTEM Collaboration; Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bossini, E.; Bozzo, M.; Brogi, P.; Brücken, E.; Buzzo, A.; Cafagna, F. S.; Calicchio, M.; Catanesi, M. G.; Covault, C.; Csanád, M.; Csörgő, T.; Deile, M.; Eggert, K.; Eremin, V.; Ferretti, R.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Intonti, R. A.; Kašpar, J.; Kopal, J.; Kundrát, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lokajíček, M.; Lo Vetere, M.; Rodríguez, F. Lucas; Macrí, M.; Mäki, T.; Mercadante, A.; Minafra, N.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Palazzi, P.; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Santroni, A.; Scribano, A.; Smajek, J.; Snoeys, W.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Vítek, M.; Welti, J.; Whitmore, J.

    2013-01-01

    At the LHC energy of \\sqrt s = 7\\,{ { TeV}} , under various beam and background conditions, luminosities, and Roman Pot positions, TOTEM has measured the differential cross-section for proton-proton elastic scattering as a function of the four-momentum transfer squared t. The results of the different analyses are in excellent agreement demonstrating no sizeable dependence on the beam conditions. Due to the very close approach of the Roman Pot detectors to the beam center (≈5σbeam) in a dedicated run with β* = 90 m, |t|-values down to 5·10-3 GeV2 were reached. The exponential slope of the differential elastic cross-section in this newly explored |t|-region remained unchanged and thus an exponential fit with only one constant B = (19.9 ± 0.3) GeV-2 over the large |t|-range from 0.005 to 0.2 GeV2 describes the differential distribution well. The high precision of the measurement and the large fit range lead to an error on the slope parameter B which is remarkably small compared to previous experiments. It allows a precise extrapolation over the non-visible cross-section (only 9%) to t = 0. With the luminosity from CMS, the elastic cross-section was determined to be (25.4 ± 1.1) mb, and using in addition the optical theorem, the total pp cross-section was derived to be (98.6 ± 2.2) mb. For model comparisons the t-distributions are tabulated including the large |t|-range of the previous measurement (TOTEM Collaboration (Antchev G. et al), EPL, 95 (2011) 41001).

  7. ELASTIC SCATTERING OF PROTONS FROM $\\sqrt{s} = 23.5~{\\rm GeV}$ to 7 TeV FROM A GENERALIZED BIALAS-BZDAK MODEL

    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.

  8. Study of proton resonance structure in {sup 27}P via resonant elastic scattering of {sup 26}Si+p

    SciTech Connect

    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.

  9. Contribution of two-boson exchange with {delta}(1232) excitation to parity-violating elastic electron-proton scattering

    SciTech Connect

    Nagata, Keitaro; Kao, C. W.; Zhou Haiqing; Yang Shinnan

    2009-06-15

    We study the leading electroweak corrections in the precision measurement of the strange form factors. Specifically, we calculate the two-boson exchange (TBE), two-photon exchange (TPE) plus {gamma}Z exchange ({gamma}ZE), and corrections with {delta}(1232) excitation to the parity-violating asymmetry of the elastic electron-proton scattering. The interplay between nucleon and {delta} contributions is found to depend strongly on the kinematics, as {delta}{sub {delta}} begins as negligible at backward angles but becomes very large and negative and dominant at forward angles, while {delta}{sub N} always stays positive and decreases monotonically with increasing {epsilon}. The total TBE corrections to the extracted values of G{sub E}{sup s}+{beta}G{sub M}{sup s} in recent experiments of HAPPEX and G0 are, depending on kinematics, found to be large and range between 13% and -75%, but are found to be small in the case of A4 experiments.

  10. Parity violation in the elastic scattering from the proton in Hall A

    SciTech Connect

    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.

  11. Two-Photon Exchange Effects in Elastic Electron-Proton Scattering

    SciTech Connect

    Johnson, Myriam James

    2013-08-01

    Two methods, Rosenbluth separation and polarization transfer, can be used to extract the proton form factor ratio μp GEp/GMp, 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 Q2, from 0.40 to 5.76 GeV2. Reduced cross sections were found to 1.1% or better for Q2 less than 3 GeV2 increasing to 4% at 5.76 GeV2 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 sufficiently precise to show nonzero curvature. Our data begins to hint at negative curvature but does not yet show a significant departure from zero.

  12. HZETRN: neutron and proton production in quasi-elastic scattering of GCR heavy-ions

    NASA Technical Reports Server (NTRS)

    Shavers, M. R.; Cucinotta, F. A.; Wilson, J. W.

    2001-01-01

    The development of transport models for radiation shielding design and evaluation has provided a series of deterministic computer codes that describe galactic cosmic radiation (GCR), solar particle events, and experimental beams at particle accelerators. These codes continue to be modified to accommodate new theory and improvements to the particle interaction database (Cucinotta et al., 1994, NASA Technical Paper 3472, US Government Printing Office, Washington DC). The solution employed by the heavy-ion transport code HZETRN was derived with the assumption that nuclear fragments are emitted with the same velocity as the incident ion through velocity conserving nuclear interactions. This paper presents a version of the HZETRN transport code that provides a more realistic distribution of the energy of protons and neutrons emitted from GCR interactions in shields. This study shows that the expected GCR dose equivalent is lower than previously calculated for water shields that are less than 110 g cm-2 thick. Calculations of neutron energy spectra in low Earth orbit indicate substantial contributions from relativistic neutrons. c2001 Elsevier Science Ltd. All rights reseved.

  13. K-shell ionization probability in elastic proton scattering on /sup 138/Ba through an f/sub 7/2/ isobaric-analog resonance

    SciTech Connect

    Dost, M.; Lorek, R.; Roehl, S.; Seidel, J.; Koenig, W.

    1985-10-01

    The bombarding energy dependence of the K-shell ionization probability P/sub K/ was measured in elastic proton scattering on /sup 138/Ba at energies near the 69-keV-wide f/sub 7/2/ isobaric-analog resonance at 9.965 MeV. The best simultaneous fit to P/sub K/ in the scattering angle intervals 45/sup 0/--80/sup 0/ and 100/sup 0/--135/sup 0/ yields R/sub 0/ = -0.30 +- 0.30 for the tangent of the phase angle of the semiclassical monopole ionization amplitude.

  14. A 3% Measurement of the Beam Normal Single Spin Asymmetry in Forward Angle Elastic Electron-Proton Scattering using the Qweak Setup

    SciTech Connect

    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.

  15. Totem Results on Elastic Scattering and Total Cross-Section

    NASA Astrophysics Data System (ADS)

    Kašpar, Jan

    2015-06-01

    TOTEM is an LHC experiment dedicated to forward hadronic physics. In this contribution, an update on two main parts of its physics programme is given: proton-proton elastic scattering and total cross-section.

  16. Proton (antiproton) elastic scattering at energies from FNAL to the LHC in the tripole Pomeron-Odderon model

    NASA Astrophysics Data System (ADS)

    Martynov, E.

    2013-06-01

    The model of elastic scattering amplitudes dominated by the triple (at t=0) Pomeron pole suggested earlier is modified to confront to existing experimental data on pp and p¯p total and differential cross sections at s≥19GeV and |t|≤14.2GeV2 including the newest TOTEM data. Predictions for the future TOTEM measurements at 13 and 14 TeV are given.

  17. Empirical parametrization of the two-photon-exchange effect contributions to the electron-proton elastic scattering cross section

    SciTech Connect

    Qattan, I. A.; Alsaad, A.

    2011-05-15

    The most recent electron-proton elastic scattering data were re-analyzed using an empirical parametrization of the two-photon-exchange (TPE) effect contributions to {sigma}{sub R}. The TPE effect contribution F(Q{sup 2},{epsilon}) was double Taylor series expanded as a polynomial of order n keeping only terms linear in {epsilon} to account for the experimentally observed and verified linearity of the Rosenbluth plots. We fix the ratio R=G{sub Ep}/G{sub Mp} to be that obtained from a fit to the recoil-polarization data and parametrize {sigma}{sub R} 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 G{sub Mp}{sup 2} 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(Q{sup 2})/G{sub Mp}{sup 2} which represents the ratio of the TPE and one-photon-exchange (OPE) effect contributions to the intercept of {sigma}{sub R} is large and it ranges 3%-88%. The ratio R{sub 1{gamma}x2{gamma}={tau}}f(Q{sup 2})/G{sub Ep}{sup 2} which represents the ratio of the TPE and OPE effect contributions to the slope of {sigma}{sub R} is also large, reaching a value of 12.0-14.4 at Q{sup 2}= 5.25 (GeV/c){sup 2}. The ratio R{sub 1{gamma}x2{gamma}} 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 {sigma}{sub R}. Moreover, our analysis shows that the extracted G{sub Ep}{sup 2} and G{sub Mp}{sup 2} using the conventional Rosenbluth separation method can in fact be broken into the usual OPE and TPE contributions. Therefore, {sigma}{sub R} can in fact be derived under weaker conditions than those imposed by the Born approximation. Our results show that the TPE amplitudes, g(Q{sup 2})/G{sub Mp}{sup 2} and f(Q{sup 2})/G{sub Mp}{sup 2}, are sizable and grow with Q{sup 2} value up to Q{sup 2}{approx}6 (Ge

  18. Measurement of the analyzing power for pion proton elastic scattering between 471 and 687 MeV/c

    SciTech Connect

    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.

  19. Probing the cluster structure of 7Li via elastic scattering on protons and deuterons in inverse kinematics

    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.

  20. Nucleas (hadron) nucleus elastic scattering and geometrical picture

    SciTech Connect

    Aleem F.; Ali, S.; Saleem, M.

    1995-08-01

    A comprehensive explanation of nucleus-nucleus and hadron-nucleus elastic scattering is elusive ever since the measurements of these reactions were made. By proposing energy dependent hadronic form factors for deuteron and alpha, in analogy to that of the proton as suggested by Chou and Yang recently, the authors have fitted all the available data for alpha-alpha and deuteron-deuteron elastic scattering. In order to further verify the validity of the proposed form factor, they have also fitted the data for proton-alpha and proton-deuteron elastic scattering. It is concluded that the hadronic matter is expanding with an increase in energy. 30 refs., 11 figs.

  1. Determination of the weak charge of the proton through parity violating asymmetry measurements in the elastic e+p scattering

    NASA Astrophysics Data System (ADS)

    Subedi, Adesh

    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, sin2θ W. The final Qweak measurement will provide the most precise measurement of the weak mixing angle below the Z° 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 muA 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 sin2θW = 0.23429 +/- 0.00211.

  2. Two-photon exchange corrections to elastic electron-proton scattering at large momentum transfer within the SCET approach

    NASA Astrophysics Data System (ADS)

    Kivel, N.; Vanderhaeghen, M.

    2013-04-01

    We calculate the two-photon exchange (TPE) corrections in the region where the kinematical variables describing the elastic ep scattering are moderately large momentum scales relative to the soft hadronic scale. For such kinematics we use the QCD factorization approach formulated in the framework of the soft-collinear effective theory (SCET). Such technique allows us to develop a description for the soft-spectator scattering contribution which is found to be important in the region of moderately large scales. Together with the hard-spectator contribution we present the complete factorization formulas for the TPE amplitudes at the leading power and leading logarithmic accuracy. The momentum region where both photons are hard is described by only one new nonperturbative SCET form factor. It turns out that the same form factor also arises for wide-angle Compton scattering which is also described in the framework of the SCET approach. This allows us to estimate the soft-spectator contribution associated with the hard photons in a model independent way. The main unknown in our description of the TPE contribution is related with the configuration where one photon is soft. The nonperturbative dynamics in this case is described by two unknown SCET amplitudes. We use a simple model in order to estimate their contribution. The formalism is then applied to a phenomenological analysis of existing data for the reduced cross section as well as for the transverse and longitudinal polarization observables.

  3. Microscopic analysis of Be,1110 elastic scattering on protons and nuclei, and breakup processes of 11Be within the 10Be +n cluster model

    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.

  4. Determination of the weak charge of the proton through parity violating asymmetry measurements in the elastic e+p scattering

    SciTech Connect

    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, sin2(theta_W). The final Qweak measurement will provide the most precise measurement of the weak mixing angle below the Z0 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 sin2(theta_W) = 0.23429 ± 0.00211.

  5. Elastic and inelastic scattering of polarized protons from carbon-12 at 400, 600, and 700 MeV

    SciTech Connect

    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.

  6. Elastic and diffractive scattering at D0

    SciTech Connect

    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.

  7. 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.

  8. Systematic CDCC calculations for 11Be + p elastic scattering

    NASA Astrophysics Data System (ADS)

    Chen, Jie; Lou, JianLing; Pang, DanYang; Ye, YanLin

    2016-03-01

    Continuum discretised coupled-channels (CDCC) method with a 10Be(0+) + n two-body cluster model is applied to systematically analyze the elastic scattering of the halo nucleus 11Be from the proton target at various incident energies below 100 MeV/nucleon. Using the renormalized 10Be- p potential deduced from the 10Be + p elastic scattering data, the differential cross sections of 11Be + p scattering are well reproduced by the CDCC calculations without any further adjustment parameters, demonstrating the applicability of this approach for describing the scattering of exotic nuclei based on the scattering of the less exotic core nuclei.

  9. Microscopic analysis of 10,11Be elastic scattering on protons and 12C and breakup processes of 11Be within the 10Be+n cluster model

    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.

  10. Two-photon exchange in electron-trinucleon elastic scattering

    NASA Astrophysics Data System (ADS)

    Kobushkin, A. P.; Timoshenko, Ju. V.

    2013-10-01

    We discuss two-photon exchange (TPE) in elastic electron scattering off the trinucleon systems, 3He and 3H. The calculations are done in the semirelativistic approximation with the trinucleon wave functions obtained with the Paris and CD-Bonn nucleon-nucleon potentials. An applicability area of the model is wide enough and includes the main part of kinematical domain where experimental data exist. All three TPE amplitudes (generalized form factors) for electron 3He elastic scattering are calculated. We find that the TPE amplitudes are a few times more significant in the scattering of electrons off 3He then in the electron-proton scattering.

  11. Electron-Hydrogen Elastic Scattering

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.

    2004-01-01

    Scattering by single-electron systems is always of interest because the wave function of the target is known exactly. Various approximations have been employed to take into account distortion produced in the target. Among them are the method of polarized orbitals and the close coupling approximation. Recently, e-H and e-He+ S-wave scattering in the elastic region has been studied using the Feshbach projection operator formalism. In this approach, the usual Hartree-Fock and exchange potentials are augmented by an optical potential and the resulting phase shifts have rigorous lower bounds. Now this method is being applied to the e-H P-wave scattering in the elastic region. The number of terms in the Hylleraas-type wave function for the 1,3 P phase shifts is 84 and the resulting phase shifts (preliminary) are given. The results have been given up to five digits because to that accuracy they are rigorous lower bounds. They are in general agreement with the variational (VAR) results of Armstead, and those obtained from the intermediate energy R-matrix method (RM) of Scholz et al., and the finite element method (FEM) of Botero and Shertzer. The later two methods do not provide any bounds on phase shifts.

  12. Measurement of the polarization parameter in proton-neutron elastic scattering at 1. 30, 1. 39, 1. 59, and 1. 82 GeV/c

    SciTech Connect

    Sakuda, M.; Isagawa, S.; Ishimoto, S.; Kabe, S.; Masaike, A.; Morimoto, K.; Ogawa, K.; Suetake, M.; Takasaki, F.; Watase, Y.; Kim, N.; Kobayashidouble-dagger, S.; Murakami, A.; de Lesguen, A.; Nakajima, K.; Nakada, S.; Wada, T.; Yamachi, I.

    1982-04-01

    The polarization parameters of the pn elastic scattering were measured at beam momenta between 1.30 and 1.82 GeV/c. The results are discussed in comparison with the partial-wave analysis of Hashimoto and Hoshizaki.

  13. Elastic scattering with weakly bound projectiles

    SciTech Connect

    Figueira, J. M.; Abriola, D.; Arazi, A.; Capurro, O. A.; Marti, G. V.; Martinez Heinmann, D.; Pacheco, A. J.; Testoni, J. E.; Barbara, E. de; Fernandez Niello, J. O.; Padron, I.; Gomes, P. R. S.; Lubian, J.

    2007-02-12

    Possible effects of the break-up channel on the elastic scattering threshold anomaly has been investigated. We used the weakly bound 6,7Li nuclei, which is known to undergo break-up, as projectiles in order to study the elastic scattering on a 27Al target. In this contribution we present preliminary results of these experiments, which were analyzed in terms of the Optical Model and compared with other elastic scattering data using weakly bound nuclei as projectile.

  14. Evaluation of the Proton Charge Radius from Electron–Proton Scattering

    SciTech Connect

    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.

  15. Decoherence due to Elastic Rayleigh Scattering

    NASA Astrophysics Data System (ADS)

    Uys, H.; Biercuk, M. J.; Vandevender, A. P.; Ospelkaus, C.; Meiser, D.; Ozeri, R.; Bollinger, J. J.

    2010-11-01

    We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of light off resonant with higher lying excited states. We demonstrate that under appropriate conditions, elastic Rayleigh scattering can be the dominant source of decoherence, contrary to previous discussions in the literature. We show that the elastic-scattering decoherence rate of a two-level system is given by the square of the difference between the elastic-scattering amplitudes for the two levels, and that for certain detunings of the light, the amplitudes can interfere constructively even when the elastic-scattering rates from the two levels are equal. We confirm this prediction through calculations and measurements of the total decoherence rate for a superposition of the valence electron spin levels in the ground state of Be+9 in a 4.5 T magnetic field.

  16. Decoherence due to elastic Rayleigh scattering.

    PubMed

    Uys, H; Biercuk, M J; Vandevender, A P; Ospelkaus, C; Meiser, D; Ozeri, R; Bollinger, J J

    2010-11-12

    We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of light off resonant with higher lying excited states. We demonstrate that under appropriate conditions, elastic Rayleigh scattering can be the dominant source of decoherence, contrary to previous discussions in the literature. We show that the elastic-scattering decoherence rate of a two-level system is given by the square of the difference between the elastic-scattering amplitudes for the two levels, and that for certain detunings of the light, the amplitudes can interfere constructively even when the elastic-scattering rates from the two levels are equal. We confirm this prediction through calculations and measurements of the total decoherence rate for a superposition of the valence electron spin levels in the ground state of 9Be+ in a 4.5 T magnetic field. PMID:21231210

  17. Study of Proton Resonances in 2626Si and 27P by the Elastic Scattering of 1H(25Al, p) 25Al, 1H(26Si, p)26Si

    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.

  18. Analysis of elastic scattering and breakup of {sup 11}li in collisions with protons using a dynamical two-cluster model

    SciTech Connect

    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.

  19. Measurement of the transverse beam spin asymmetry in elastic electron-proton scattering and the inelastic contribution to the imaginary part of the two-photon exchange amplitude.

    PubMed

    Maas, F E; Aulenbacher, K; Baunack, S; Capozza, L; Diefenbach, J; Gläser, B; Imai, Y; Hammel, T; von Harrach, D; Kabuss, E-M; Kothe, R; Lee, J H; Sanchez-Lorente, A; Schilling, E; Schwaab, D; Stephan, G; Weber, G; Weinrich, C; Altarev, I; Arvieux, J; Elyakoubi, M; Frascaria, R; Kunne, R; Morlet, M; Ong, S; Vandewiele, J; Kowalski, S; Suleiman, R; Taylor, S

    2005-03-01

    We report on a measurement of the asymmetry in the scattering of transversely polarized electrons off unpolarized protons, A( perpendicular), at two Q2 values of 0.106 and 0.230 (GeV/c)(2) and a scattering angle of 30 degrees proton. PMID:15783877

  20. 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.

  1. Backward elastic pd scattering at 316, 364, 470 and 590 MeV

    NASA Technical Reports Server (NTRS)

    Alder, J. C.; Dollhopf, W.; Lunke, C.; Perdrisat, C. F.; Roberts, W. K.; Kitching, P.; Moss, G. F.; Olsen, W. C.; Priest, J. R.

    1971-01-01

    Preliminary results are reported from a part of the data obtained at the NASA Space Radiation Effect Laboratory for the elastic scattering of protons by deuterons in the backward hemisphere. The data is averaged over a proton angle interval which corresponds to the angular resolution on the correlation angle, given the proton bin used in the data analysis.

  2. A study of the proton resonant property in 22Mg by elastic scattering of 21Na + p and its astrophysical implication in the 18Ne(α, p)21Na reaction rate

    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.

  3. Asymmetry Measurement in the Elastic Pion-Proton Scattering at 1.94 and 2.07 GeV/c

    SciTech Connect

    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.

  4. 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).

  5. Decoherence due to elastic Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Uys, H.; Biercuk, M. J.; Vandevender, A. P.; Ospelkaus, C.; Bollinger, J. J.; Meiser, D.

    2010-03-01

    Off-resonant light scattering (spontaneous emission) is an important source of decoherence in many coherent control experiments. Typically one focuses on the effects of Raman scattering, in which an atomic state is changed by a single scattering event. We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of off-resonant light. By a master equation technique we show that for a two-level superposition the elastic decoherence rate is the square of the difference between the two elastic scattering amplitudes. Thus, if the light detunings for the two states have opposite sign, the amplitudes interfere constructively and can result in a large decoherence rate. We calculate and measure the total decoherence rate for a superposition state of the valence electron spin in the ground state of ^9Be^+ in a 4.5 T magnetic field. We find that for large (˜20 GHz) detunings, decoherence due to elastic Rayleigh scattering can be 5 times larger than decoherence due to Raman scattering. This is in contrast with workootnotetextR. Ozeri, et al., PRL 95, 030403 (2005) at low magnetic field where decoherence was dominated by Raman scattering.

  6. 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.

  7. Hadronic uncertainties in the elastic scattering of supersymmetric dark matter

    SciTech Connect

    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 matrix elements linked to the {pi}-nucleon {sigma} term, which affects the ratio of cross sections on proton and neutron targets as well as their absolute values. This uncertainty is already impacting the interpretations of experimental searches for cold dark matter. We plead for an experimental campaign to determine better the {pi}-nucleon {sigma} term. Uncertainties in the spin content of the proton affect significantly, but less strongly, the calculation of rates used in indirect searches.

  8. Elastic scattering and reactions of light exotic beams

    NASA Astrophysics Data System (ADS)

    Keeley, N.; Alamanos, N.; Kemper, K. W.; Rusek, K.

    2009-10-01

    The present work provides a literature survey of elastic scattering of exotic nuclei from 6He to 17F. It presents a set of definitions that allow different analyses to be put into a common language. A calculational approach is proposed that yields consistent results across different beams and targets so that conclusions concerning the influence of virtual and real breakup as well as transfer couplings on the elastic scattering may be drawn. Calculations of elastic scattering around the Coulomb barrier are emphasised, employing a Pb target whose large Z allows the interplay between nuclear and Coulomb forces to be exploited to maximise possible effects arising from proton or neutron haloes or skins. A series of test calculations is performed and where possible compared to data, demonstrating that there are instances where coupling to transfer channels can have a large effect on the elastic scattering angular distributions. By careful choice of target/beam combination, different aspects of the coupling effects may be emphasised.

  9. Elastic Hadron Scattering on Li Isotopes at Intermediate Energies

    SciTech Connect

    Zhusupov, M.A.; Imambekov, O.; Ibraeva, E.T.

    2005-01-01

    The elastic scattering of hadrons (protons, charged pions, and positively charged kaons) on {sup 6,7,8}Li nuclei is analyzed on the basis of Glauber-Sitenko diffraction theory. A few nuclear-wave-function versions found within two- and three-particle potential cluster models are used in the calculations. It is shown that the application of these wave functions in diffraction theory makes it possible to describe adequately the experimental differential cross sections and analyzing powers in hadron scattering at intermediate energies. In this study, particular attention is given to a comparison of the scattering of different particles on the same target nucleus, as well as to a comparison of scattering of particles of the same sort on different target nuclei.

  10. Asymptotic behaviour of backward elastic scattering

    NASA Astrophysics Data System (ADS)

    Germond, J. F.; Lombard, R. J.

    1988-05-01

    We discuss a compact formula proposed by Dias de Deus and Pimenta for the asymptotic value of the elastic scattering amplitude at backward angles. Improvements and generalization are obtained by means of the saddle-point method which corroborate old calculations by Serber.

  11. Coherent elastic neutrino-nucleus scattering

    NASA Astrophysics Data System (ADS)

    Scholberg, Kate

    2015-05-01

    I describe physics potential and experimental prospects for coherent elastic neutrino-nucleus scattering (CEvNS), a process which has not yet been observed. Germanium- based detectors represent a promising technology for CEvNS experiments. I focus primarily on stopped-pion neutrino sources.

  12. Elastic electron scattering by ethyl vinyl ether

    SciTech Connect

    Khakoo, M. A.; Hong, L.; Kim, B.; Winstead, C.; McKoy, V.

    2010-02-15

    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 {pi}{sup *} shape resonance. The agreement between the calculated and measured cross sections is generally good.

  13. 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. .

  14. Excitation function of elastic pp scattering from a unitarily extended Bialas-Bzdak model

    NASA Astrophysics Data System (ADS)

    Nemes, F.; Csörgő, T.; Csanád, M.

    2015-05-01

    The Bialas-Bzdak model of elastic proton-proton scattering assumes a purely imaginary forward scattering amplitude, which consequently vanishes at the diffractive minima. We extended the model to arbitrarily large real parts in a way that constraints from unitarity are satisfied. The resulting model is able to describe elastic pp scattering not only at the lower ISR energies but also at √ {s} = 7 TeV in a statistically acceptable manner, both in the diffractive cone and in the region of the first diffractive minimum. The total cross-section as well as the differential cross-section of elastic proton-proton scattering is predicted for the future LHC energies of √ {s} = 13, 14, 15 TeV and also to 28 TeV. A nontrivial, significantly nonexponential feature of the differential cross-section of elastic proton-proton scattering is analyzed and the excitation function of the nonexponential behavior is predicted. The excitation function of the shadow profiles is discussed and related to saturation at small impact parameters.

  15. Results on neutrino-electron elastic scattering at AGS energies

    SciTech Connect

    Lanou, R.E.

    1984-02-26

    In an experiment designed to study elastic scattering of nu/sub ..mu../ (and anti nu/sub ..mu../) from electrons and protons via the weak neutral current, we have recently completed several extensive data taking runs. Results for the cross section of nu/sub ..mu../ + e/sup -/ ..-->.. nu/sub ..mu../ + e/sup -/ are presented based upon the first third of the available sample. Preliminary analysis of anti nu/sub ..mu../ + e/sup -/ ..-->.. anti nu/sub ..mu../ + e/sup -/ is in progress and evidence for the signal is presented.

  16. Hydrogen analysis for granite using proton-proton elastic recoil coincidence spectrometry.

    PubMed

    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

  17. 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

  18. Hard elastic scattering in QCD: Leading behavior

    SciTech Connect

    Botts, J.F.

    1989-01-01

    The author derives the asymptotic behavior of elastic meson-meson and baryon-baryon scattering at high energy and large angle t/s {approximately} O(1). The results organize both Sudakov and nonleading logarithmic corrections to independent (Landshoff) scatterings of valence quarks. He shows how to separate these contributions systematically from single scattering contributions, in a manner which suggests that the complete amplitudes should be computable perturbatively down to the dimensional counting power, in terms of hadronic wave functions. In the final chapter, the perturbative asymptotic amplitude and differential cross section for elastic pion-pion scattering is calculated numerically. For various choices of pion wave function and running coupling, the onset of power law behavior, d{sigma}/dt {approximately} s{sup {minus}5.8}, was observed. The dependence in d{sigma}/dt on the cutoff in gluon momentum, chosen to be O({Lambda}{sub QCD}/Q), was observed to be sharp for ln(s/1GeV{sup 2}) less than 1. Very small oscillations in d{sigma}/dt appear in physically realizable energies, but these are cutoff dependent, and their interpretation unclear. Higher twist effects were estimated to be roughly {approximately}15% for 2 < ln(s/1GeV{sup 2}) < 10.

  19. Exploring central opacity and asymptotic scenarios in elastic hadron scattering

    NASA Astrophysics Data System (ADS)

    Fagundes, D. A.; Menon, M. J.; Silva, P. V. R. G.

    2016-02-01

    In the absence of a global description of the experimental data on elastic and soft diffractive scattering from the first principles of QCD, model-independent analyses may provide useful phenomenological insights for the development of the theory in the soft sector. With that in mind, we present an empirical study on the energy dependence of the ratio X between the elastic and total cross sections; a quantity related to the evolution of the hadronic central opacity. The dataset comprises all the experimental information available on proton-proton and antiproton-proton scattering in the c.m. energy interval 5 GeV-8 TeV. Generalizing previous works, we discuss four model-independent analytical parameterizations for X, consisting of sigmoid functions composed with elementary functions of the energy and three distinct asymptotic scenarios: either the standard black disk limit or scenarios above or below that limit. Our two main conclusions are the following: (1) although consistent with the experimental data, the black disk does not represent an unique solution; (2) the data reductions favor a semi-transparent scenario, with asymptotic average value for the ratio X bar = 0.30 ± 0.12. In this case, within the uncertainty, the asymptotic regime may already be reached around 1000 TeV. We present a comparative study of the two scenarios, including predictions for the inelastic channel (diffraction dissociation) and the ratio associated with the total cross-section and the elastic slope. Details on the selection of our empirical ansatz for X and physical aspects related to a change of curvature in this quantity at 80-100 GeV, indicating the beginning of a saturation effect, are also presented and discussed.

  20. 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.

  1. Radiative corrections to polarization observables in electron-proton scattering

    NASA Astrophysics Data System (ADS)

    Borisyuk, Dmitry; Kobushkin, Alexander

    2014-08-01

    We consider radiative corrections to polarization observables in elastic electron-proton scattering, in particular, for the polarization transfer measurements of the proton form factor ratio μGE/GM. The corrections are of two types: two-photon exchange (TPE) and bremsstrahlung (BS); in the present work we pay special attention to the latter. Assuming small missing energy or missing mass cutoff, the correction can be represented in a model-independent form, with both electron and proton radiation taken into account. Numerical calculations show that the contribution of the proton radiation is not negligible. Overall, at high Q2 and energies, the total correction to μGE/GM grows, but is dominated by TPE. At low energies both TPE and BS may be significant; the latter amounts to ˜0.01 for some reasonable cut-off choices.

  2. 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.

  3. Neutron elastic scatter for detection and identification of obscured objects

    NASA Astrophysics Data System (ADS)

    Gomberg, Henry J.; Charatis, George; Wang, David; McEllistrem, Marcus R.

    1993-11-01

    Neutron Elastic Scatter (NES) may be used for non-destructively assaying materials for the presence of narcotics, explosives, or other contraband. The technology relies on the high penetrating power of neutrons to reach through varying thickness of shielding materials, and also on the large probabilities for elastic scattering of neutrons. Elastic scattering probabilities are the largest of all neutron induced events, exceeding any single non-elastic process typically by a factor of ten or more. Indeed, usually the elastic scattering probability is larger than the sum of all inelastic processes.

  4. Elastic Scattering - Past, Present and Future

    SciTech Connect

    Fazal-e-Aleem; Rashid, Haris; Tahir, Sohail Afzal

    2007-02-14

    Various aspects of elastic and diffractive scattering have been studied at Fermilab and CERN. Search for more results is ongoing at RHIC and planned at LHC. In this talk, we review the progress made so far and elaborate future prospects. Theoretical study focuses on the analysis of the available data in the light of predictions of various models with special emphasis on Eikonal picture and QCD inspired models. In the light of this analysis, various possibilities have been explored with reference to RHIC and LHC measurements.

  5. Time reversal invariance violating and parity conserving effects in proton-deuteron scattering

    NASA Astrophysics Data System (ADS)

    Song, Young-Ho; Lazauskas, Rimantas; Gudkov, Vladimir

    2016-06-01

    Time reversal invariance violating parity conserving (TVPC) effects are calculated for elastic proton-deuteron scattering with proton energies up to 2 MeV. The distorted-wave Born approximation is employed to estimate TVPC matrix elements, based on hadronic wave functions, obtained by solving three-body Faddeev-Merkuriev equations in configuration space with realistic potentials.

  6. 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.

  7. Subcritical scattering from buried elastic shells.

    PubMed

    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. PMID:17225387

  8. 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).

  9. Elastic scattering at 7 TeV and high-energy cross section for cosmic ray studies

    NASA Astrophysics Data System (ADS)

    Wibig, T.

    2012-08-01

    The recent measurements of the elastic cross section by the TOTEM Collaboration together with the first estimations of the inelastic cross sections by other LHC detectors are used to test the simplest version of the geometrical model of the proton-proton scattering. We show that the description found for lower energy data, with the modest adjustment of the model parameter extrapolation, could be, in principle, used to describe the LHC measurement and to predict the cross sections in very high energy cosmic ray domain. However, the shape of the first elastic dip in the elastic differential scattering cross section suggests that the ratio of the real to the imaginary part of the elastic amplitude falls rather fast and the analysis of the elastic cross-section fraction suggests that the geometrical picture and scaling of the proton-proton collision should be modified when entering the ultrahigh-energy domain.

  10. Model independent radiative corrections in processes of polarized electron-nucleon elastic scattering

    SciTech Connect

    Igor Akushevich; Andrei Afanasev; Mykola Merenkov

    2001-12-01

    The explicit formulae for radiative correction (RC) calculation for elastic ep-scattering is presented. Two typical measurements of polarization observables such as beam-target asymmetry or recoil proton polarization, are considered. Possibilities to take into account realistic experimental acceptances are discussed. The Fortran code MASCARAD for providing the RC procedure is presented. Numerical analysis is done for kinematical conditions of TJNAF.

  11. Model independent radiative corrections in processes of polarized electron-nucleon elastic scattering

    NASA Astrophysics Data System (ADS)

    Afanasev, A.; Akushevich, I.; Merenkov, N.

    2001-12-01

    Explicit formulas for radiative correction (RC) calculations for elastic ep scattering are presented. Two typical measurements of polarization observables, such as beam-target asymmetry or recoil proton polarization, are considered. The possibilities of taking into account realistic experimental acceptances are discussed. The FORTRAN code MASCARAD for providing the RC procedure is presented. A numerical analysis is done for the kinematical conditions of CEBAF.

  12. QED Radiative Corrections to Asymmetries of Elastic ep-scattering in Hadronic Variables

    SciTech Connect

    Alexander Ilyichev; Andrei Afanasev; Igor Akushevich; Mykola Merenkov

    2001-08-16

    Compact analytical formulae for QED radiative corrections in the processes of elastic e-p scattering are obtained in the case when kinematic variables are reconstructed from the recoil proton momentum measured. Numerical analysis is presented under kinematic conditions of current experiments at JLab.

  13. 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.

  14. Resolving the Proton Form Factor Problem with Positron-Proton Scattering

    NASA Astrophysics Data System (ADS)

    Weinstein, Lawrence

    2012-10-01

    The proton electromagnetic form factors are essential pieces of our knowledge of nucleon structure. However, Rosenbluth separation measurements of the proton electric form factor, GE(Q^2), differ from polarization transfer measurements by a factor of three at Q^2 = 5.6 (GeV/c)^2. This discrepancy must be resolved. One possible resolution is to include the contribution of hard two-photon exchange (TPE) contributions. These contributions are very difficult to calculate. However, we can directly determine the TPE effect by measuring the ratio of the positron-proton to electron-proton elastic scattering cross sections, R=σ(e^+p)/σ(e^-p), because the TPE amplitude has the same sign as the e^+p born amplitude and the opposite sign as the e^-p born amplitude. We have measured R over a wide range of momentum transfer, 0.2 <=Q^2 <=2 GeV^2, and virtual photon polarization, 0.1 <=ɛ<=0.9, using a mixed identical beam of electrons and positrons in Hall B at Jefferson Lab. This talk will describe the experimental techniques used to produce this beam, the analysis techniques to identify elastic scattering events, and some preliminary results.

  15. 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.

  16. Support minimized inversion of acoustic and elastic wave scattering

    SciTech Connect

    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.

  17. Coulomb effects on edge scattering in elastic nuclear collisions

    SciTech Connect

    Silveira, R. da; Leclercq-Willain, Ch.

    2011-04-15

    We present a qualitative analysis of the effects of the Coulomb force on the edge scattering produced in elastic nuclear collisions occurring under strong absorption conditions. This analysis is illustrated with several examples of nucleus-nucleus and antiproton-nucleus elastic scattering.

  18. Parity Violation in Proton-Proton Scattering at 47 Mev.

    NASA Astrophysics Data System (ADS)

    Tanner, Danelle Mary

    A measurement of parity-violation in proton-proton scattering at 47 MeV has been completed by observing the longitudinal analyzing power. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). where (sigma)('+)((sigma)('-)) is the scattering cross section for positive (negative) helicity. Polarized protons from an atomic beam ion source were accelerated by the 224-cm Texas A&M University cyclotron to an energy of 50 MeV, producing a vertically polarized beam. A superconducting solenoid magnet precessed the beam polarization into the horizontal plane after which a 47.6(DEGREES) bending magnet precessed the polarization into the longtitudinal direction (p(,z) = 0.69 (+OR-) 0.02). RF transitions reversed the polarization direction every 21 msec. Protons scattered from the high pressure ((DBLTURN)37 atm), 42-cm long H(,2) gas target were detected by four plastic scintillators located in the target chamber. Photomultiplier tubes amplified the light from the scintillators, providing a signal proportional to the scattered beam intensity. A lock-in amplifier (LIA) synchronized to the spin-flip frequency compared the scattered intensity to the total beam intensity, measured with a Faraday cup. The output of the LIA was integrated for one second and then read by an ADC. Polarimeters were used to monitor both beam intensity and polarization profiles. A series of tests were performed to determine the role of spurious asymmetries due to changes in beam position and angle, and due to beam intensity modulations correlated with the spin reversal. The result after correction for beam intensity modulation was A(,z) = -(4.6 (+OR-) 2.6) x 10('-7). A more conservative result, taking into account all of the possible spurious asymmetries was A(,z) = -(4.6 (+OR-) 4.2) x 10('-7).

  19. Elastic Scattering LIDAR Data Acquisition Visualization and Analysis

    Energy Science and Technology Software Center (ESTSC)

    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.

  20. The Proton Coulomb Form Factor from Polarized Inclusive e-p Scattering

    SciTech Connect

    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.

  1. Proton spin polarizabilities from polarized Compton scattering

    SciTech Connect

    B. Pasquini; D. Drechsel; M. Vanderhaeghen

    2007-07-01

    Polarized Compton scattering off the proton is studied within the framework of subtracted dispersion relations for photon energies up to 300 MeV. As a guideline for forthcoming experiments, we focus the attention on the role of the proton's spin polarizabilities and investigate the most favorable conditions to extract them with a minimum of model dependence. We conclude that a complete separation of the four spin polarizabilities is possible, at photon energies between threshold and the $\\Delta(1232)$ region, provided one can achieve polarization measurements with an accuracy of a few percent.

  2. Positron-proton to electron-proton elastic cross section ratios from CLAS

    NASA Astrophysics Data System (ADS)

    Adikaram, Dasuni; Rimal, Dipak; Weinstein, Larry; Raue, Brian

    2014-03-01

    There is a significant discrepancy between the ratio of the electromagnetic form factors of the proton measured by the Rosenbluth and the polarization transfer technique. The most likely explanation of this discrepancy is the inclusion of two-photon exchange (TPE) amplitude contributions to the elastic electron-proton cross section. The CLAS TPE experiment measured the TPE contribution in the wide range of Q2 and ɛ range using a comparison of positron-proton to electron-proton elastic cross sections (R = σ (e+ p) / σ (e- p)). Preliminary results will be presented, along with the estimations of systematic uncertainties. A detailed comparison of new results with previous R measurements and theoretical calculations will be presented. Implications of the CLAS TPE measurements on the elastic electron-proton cross section will be also discussed.

  3. Recent results on deuteron-proton scattering from RIKEN

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Kimiko

    2016-03-01

    Nucleon-deuteron (Nd) scattering, for which a rigorous formulation in terms of Faddeev equations exists and exact solutions of these equations for any dynamical input can be obtained, offers a good opportunity to study the dynamical aspects of 3NFs, such as momentum and spin dependences. Since the first indication of 3NF effects in Nd elastic scattering around 100 MeV/nucleon, precise measurements of proton-deuteron / neutron-deuteron scattering have been extensively performed at 60-300 MeV/nucleon. Direct comparison between the data and the Faddeev calculations based on realistic nucleon-nucleon forces plus 2π-exchange three nucleon forces draws the following conclusions. (1) The 3NF is definitely needed in Nd elastic scattering. (2) The spin dependent parts of the 3NFs may be deficient. (3) The shorter-range components of the 3NFs are probably required for the cross section as well as the spin observables at backward angles with increasing an incident energy.

  4. 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.

  5. A Quasi-Elastic Neutron Scattering Study of the Dynamics of Electrically Constrained Water.

    PubMed

    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

  6. Global analysis of proton elastic form factor data with two-photon exchange corrections

    SciTech Connect

    J. Arrington; W. Melnitchouk; J. A. Tjon

    2007-09-01

    We use the world's data on elastic electron-proton scattering and calculations of two-photon exchange effects to extract corrected values of the proton's electric and magnetic form factors over the full Q^2 range of the existing data. Our analysis combines the corrected Rosenbluth cross section and polarization transfer data, and is the first extraction of G_Ep and G_Mp including explicit two-photon exchange corrections and their associated uncertainties. In addition, we examine the angular dependence of the corrected cross sections, and discuss the possible nonlinearities of the cross section as a function of epsilon.

  7. Attenuation of Elastic Waves due to Scattering from Spherical Cavities and Elastic Inclusions.

    NASA Astrophysics Data System (ADS)

    Hinders, Mark Karl

    1990-01-01

    The attenuation of elastic waves due to scattering from a spherical inclusion of arbitrary size in an infinitely extended medium is investigated. The spherical scatterer and the exterior medium are isotropic, homogeneous, and linearly elastic, but of arbitrarily differing material parameters, with compressional and shear waves supported in both media. Exact expressions for scattered and transmitted fields caused by an incident plane compressional or shear wave of unit amplitude are calculated analytically and general expressions for extinction and scattering cross -sections are derived for both lossy and lossless scattering. Application to ultrasonic determination of porosity in cast aluminum is investigated.

  8. Prospects for detecting dark matter particles by elastic scattering

    SciTech Connect

    Sadoulet, B.

    1987-02-01

    The rates, signatures, and backgrounds likely to be encountered by experiments attempting to detect dark matter particles by elastic scattering are discussed. Detector material discussed includes boron, tungsten, germanium, and silicon. 14 refs., 3 figs.

  9. The two-photon exchange contribution to elastic electron-nucleon scattering at large momentum transfer

    SciTech Connect

    Andrei V. Afanasev; Stanley J. Brodsky; Carl E. Carlson; Yu-Chun Chen; Marc Vanderhaeghen

    2005-01-01

    We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer by using a quark-parton representation of virtual Compton scattering. We thus can relate the two-photon exchange amplitude to the generalized parton distributions which also enter in other wide angle scattering processes. We find that the interference of one- and two-photon exchange contribution is able to substantially resolve the difference between electric form factor measurements from Rosenbluth and polarization transfer experiments.

  10. 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.

  11. An Examination of Proton Charge Radius Extractions from e–p Scattering Data

    SciTech Connect

    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.

  12. An Examination of Proton Charge Radius Extractions from e-p Scattering Data

    NASA Astrophysics Data System (ADS)

    Arrington, John

    2015-09-01

    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.

  13. 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

  14. 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.

  15. Quasi-elastic neutron scattering studies of protein dynamics

    SciTech Connect

    Rorschach, H.E.

    1993-05-25

    Results that shed new light on the study of protein dynamics were obtained by quasi-elastic neutron scattering. The triple axis instrument H-9 supplied by the cold source was used to perform a detailed study of the quasi-elastic spectrum and the Debye-Waller factor for trypsin in powder form, in solution, and in crystals. A preliminary study of myoglobin crystals was also done. A new way to view the results of quasi-elastic scattering experiments is sketched, and the data on trypsin are presented and analyze according to this new picture.

  16. Test of 600 and 750 MeV NN matrix on elastic scattering Glauber model calculations

    NASA Astrophysics Data System (ADS)

    Brissaud, I.

    1980-09-01

    The 600 and 750 MeV proton nucleus elastic scattering cross section and polarization calculations have been performed in the framework of the Glauber model to test the pp and pn scattering amplitudes deduced from a phase shift analysis by Bystricky, Lechanoine and Lehar. It is well known that up to now we do not possess a non-phenomenological NN scattering matrix at intermediate energies. However proton-nucleus scattering analyses are used to extract information about short range correlations1), Δ resonance2) or pion condensation presences)... etc. Most scattering calculations made at these energies have been done with phenomenological NN amplitudes having a gaussian q-dependence 10050_2005_Article_BF01438168_TeX2GIFE1.gif A(q) = {kσ }/{4π }(α + i) e^{ - β ^2 q^2 /2} and 10050_2005_Article_BF01438168_TeX2GIFE2.gif C(q) = {kσ }/{4π }iq(α + i) D_e - β ^2 q^2 /2 K and σ being respectively the projectile momentum and the total pN total cross section. The parameters α, β and D are badly known and are adjusted by fitting some specific reactions as p+4He elastic scattering4). Even when these amplitudes provide good fits to the data, our understanding of the dynamics of the scattering remains obscure.

  17. rvec p + sup 13 rvec C elastic scattering at 500 MeV

    SciTech Connect

    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.

  18. 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.

  19. 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.

  20. 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.

  1. Measuring the 2{gamma} Exchange Effect in Electron-Proton Scattering at CLAS

    SciTech Connect

    Bennett, Robert Paul

    2011-10-24

    Recent results from experiments at Jefferson Laboratory, Newport News VA, which measure the ratio of the electric to magnetic form factors of the proton, G{sub E}/G{sub M}, have forced us to reexamine the single photon exchange approximation in lepton-proton elastic scattering. Discrepancies between the ratio obtained via the time-tested Rosenbluth separation method and new polarization transfer measurements, which differ by as much as a factor of three, may be resolved by considering the effect of two photon exchange (TPE). Theoretical corrections for the TPE effect are difficult due to the large number of excited nucleon states that can contribute to the process. The TPE effect can, however, be determined directly by measuring the ratio of the positron-proton to electron-proton elastic scattering cross sections, R = {sigma}(e{sup +})/{sigma}(e{sup -}), since the TPE effect changes sign with the charge of the incident particle. The CLAS TPE experiment at Jefferson Laboratory, will determine the effect of two-photon exchange in elastic lepton-proton scattering by precisely measuring the ratio of positron-proton to electron-proton elastic cross sections over a large kinematic range (0.1<{epsilon}<0.96, 0.02{<=}Q{sup 2}{<=}2.0). We will accomplish this by directing the 5.5 GeV primary electron beam, provided by the Continuous Electron Beam Accelerator Facility (CEBAF), onto a set of radiators and converters to produce simultaneous and identical beams of electron and positrons. Acceptance and efficiency concerns are minimized by only considering the ratios of the elastic cross sections and switching polarity of magnets in the beam line and the spectrometer. Guided by the results of a short 2006 test run and extensive GEANT based modeling, new shielding and beam line components were designed to maximize luminosity. The unique experimental design and challenges of the TPE experiment and the projected luminosities will be presented.

  2. Elastic scattering by finitely many point-like obstacles

    NASA Astrophysics Data System (ADS)

    Hu, Guanghui; Sini, Mourad

    2013-04-01

    This paper is concerned with the time-harmonic elastic scattering by a finite number N of point-like obstacles in {{R}}^n (n = 2, 3). We analyze the N-point interactions model in elasticity and derive the associated Green's tensor (integral kernel) in terms of the point positions and the scattering coefficients attached to them, following the approach in quantum mechanics for modeling N-particle interactions. In particular, explicit expressions are given for the scattered near and far fields corresponding to elastic plane waves or point-source incidences. As a result, we rigorously justify the Foldy method for modeling the multiple scattering by finitely many point-like obstacles for the Lamé model. The arguments are based on the Fourier analysis and the Weinstein-Aronszajn inversion formula of the resolvent for the finite rank perturbations of closed operators in Hilbert spaces.

  3. Experimental study of quasi-elastic scattering of ultracold neutrons

    NASA Astrophysics Data System (ADS)

    Steyerl, A.; Yerozolimsky, B. G.; Serebrov, A. P.; Geltenbort, P.; Achiwa, N.; Pokotilovski, Yu. N.; Kwon, O.; Lasakov, M. S.; Krasnoshchokova, I. A.; Vasilyev, A. V.

    2002-08-01

    Ultracold neutrons (UCN) are lost from traps if they are quasi-elastically scattered from the wall with an energy gain sufficient to exceed the Fermi potential for the wall. Possible mechanisms of a quasi-elastic energy transfer are, for instance, scattering from hydrogen diffusing in an impurity surface layer or on surface waves at a liquid wall. Using two different experimental methods at the UCN source of the Institut Laue-Langevin we have investigated both the energy-gain and the energy-loss side of quasi-elastic UCN scattering on Fomblin grease coated walls. For Fomblin oil and similar new types of oil we report up-scattering data as a function of temperature and energy transfer. These low-temperature oils may be used in an improved measurement of the neutron lifetime, which requires extremely low wall reflection losses.

  4. Electron impact elastic scattering and vibrational excitation of ethylene

    NASA Astrophysics Data System (ADS)

    Khakoo, Murtadha; Khakoo, Sabaha; Sakaamini, Ahmad; Hargreaves, Leigh; Winstead, Carl; McKoy, Vince

    2015-09-01

    Experimental and theoretical (Schwinger Multi-Channel model) differential scattering cross sections for low energy electron elastic scattering plus vibrational excitation (4 energy loss features) of ethylene are presented. The incident electron energy range is from 0.5eV to 100eV and scattering angles of 5 to 130 degrees. Comparisons with theory and past available measurements show good agreement in general. Funded by a National Science Foundation Collaborative Research Grant to CSUF and Caltech.

  5. Target-charge dependence of the breakup coupling effects in the elastic scattering of 8B

    NASA Astrophysics Data System (ADS)

    Kucuk, Y.; Aciksoz, E.

    2016-04-01

    We perform continuum discretized coupled-channels calculations for the elastic scattering of 8B on different targets to trace where the Coulomb-nuclear breakup coupling effects start to be dominant in the interaction of the proton halo nuclei. We observe a qualitative difference in angular distributions when the charge of the target increases as seen in the case of neutron halos, but the Coulomb-nuclear interference peak begins to disappear clearly at a relatively smaller value of Z T for the proton halos.

  6. Elastic neutrino electron scattering at Brookhaven

    SciTech Connect

    Cutts, D.

    1984-01-01

    A progress report is given of Experiment 734 at Brookhaven, with a focus on the elastic reactions nu/sub ..mu../ + e/sup -/ ..-->.. nu/sub ..mu../ + e/sup -/ and anti nu/sub ..mu../ + e/sup -/ ..-->.. anti nu/sub ..mu../ + e/sup -/. The present status, recent results, and future plans are discussed.

  7. Ay Measurement in p→p-Elastic Scattering at Small Angles

    NASA Astrophysics Data System (ADS)

    Macharashvili, G.

    2016-02-01

    The proton analysing power in p→p elastic scattering has been measured at small angles at COSY-ANKE at 796MeV and five other beam energies between 1.6 and 2.4GeV using a polarized proton beam. The asymmetries obtained by detecting the fast proton in the ANKE forward detector or the slow recoil proton in a silicon tracking telescope are completely consistent. The sources of the systematic uncertainties and the time stability issue were considered. The ANKE data at the higher energies lie well above the predictions of the most recent partial wave solution at small angles. An updated phase shift analysis that uses the ANKE results together with the World data leads to a better description of these new measurements.

  8. Absolute Beam Energy Measurement using Elastic ep Scattering at Thomas Jefferson National Accelerator Facility

    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.

  9. Elastic electron scattering from formic acid

    SciTech Connect

    Trevisan, Cynthia S.; Orel, Ann E.; Rescigno, Thomas N.

    2006-07-31

    Following our earlier study on the dynamics of low energy electron attachment to formic acid, we report the results of elastic low-energy electron collisions with formic acid. Momentum transfer and angular differential cross sections were obtained by performing fixed-nuclei calculations employing the complex Kohn variational method. We make a brief description of the technique used to account for the polar nature of this polyatomic target and compare our results with available experimental data.

  10. Weak charge of the proton: loop corrections to parity-violating electron scattering

    SciTech Connect

    Wally Melnitchouk

    2011-05-01

    I review the role of two-boson exchange corrections to parity-violating elastic electron–proton scattering. Direct calculations of contributions from nucleon and Delta intermediate states show generally small, [script O](1–2%), effects over the range of kinematics relevant for proton strangeness form factor measurements. For the forward angle Qweak experiment at Jefferson Lab, which aims to measure the weak charge of the proton, corrections from the gammaZ box diagram are computed within a dispersive approach and found to be sizable at the E~1 GeV energy scale of the experiment.

  11. 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.

  12. Checks of asymptotia in pp elastic scattering at LHC

    NASA Astrophysics Data System (ADS)

    Grau, Agnes; Pacetti, Simone; Pancheri, Giulia; Srivastava, Yogendra N.

    2012-07-01

    We parametrize TOTEM data for the elastic differential pp cross section at √{s}=7 TeV in terms of two exponentials with a relative phase. We employ two previously derived sum rules for pp elastic scattering amplitude in impact parameter space to check whether asymptotia has been reached at the LHC. A detailed study of the TOTEM data for the elastic differential cross section at √{s}=7 TeV is made and it is shown that, within errors, the asymptotic sum rules are satisfied at LHC. We propose to use this parametrization to study forthcoming higher energy data.

  13. The First Measurement of the Elastic pp-scattering Spin Parameters at {radical}(s) = 200 GeV

    SciTech Connect

    Bueltmann, S.; Chiang, I. H.; Chrien, R. E.; Drees, A.; Gill, R. L.; Guryn, W.; Landgraf, J.; Ljubicic, T. A.; Lynn, D.; Pearson, C.; Pile, P.; Rusek, A.; Sakitt, M.; Tepikian, S.; Yip, K.; Chwastowski, J.; Pawlik, B.; Haguenauer, M.; Bogdanov, A. A.; Nurushev, S. B.

    2007-06-13

    Elastic scattering of polarized protons in the range of very small momentum transferred was studied for the first time at {radical}(s) = 200 GeV in the experiment pp2pp at RHIC. This article presents the single spin asymmetry A{sub N} and the double spin asymmetries A{sub NN} and A{sub SS} measured in this experiment.

  14. 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.

  15. 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.

  16. Contraband detection via neutron elastic scattering

    SciTech Connect

    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.

  17. High energy parton-parton elastic scattering in QCD

    SciTech Connect

    Tang, W.K.

    1993-08-01

    We show that the high energy limit of quark-quark, or gluon-gluon, elastic scattering is calculable in terms of the BFKL pomeron when {minus}t {much_gt} {Lambda}{sub QCD}{sup 2}. Surprisingly, this on-shell amplitudes does not have infrared divergences in the high energy limit.

  18. Elastic scattering of e- and e+ from Rb and Cd

    NASA Technical Reports Server (NTRS)

    Pangantiwar, A. W.; Srivastava, Rajesh

    1990-01-01

    Differential cross section results are calculated for the elastic scattering of electrons and positrons from the ground state of Rb and Cd atoms. An optical model potential approach is used for the calculation. Results are compared with the available electron impact experimental results.

  19. 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.

  20. Rayleigh scattering and nonlinear inversion of elastic waves

    SciTech Connect

    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.

  1. Measurement of the Wolfenstein parameters for proton-proton and proton-neutron scattering at 500 MeV

    SciTech Connect

    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.

  2. Amplitude description of elastic pp scattering at 800 MeV

    NASA Astrophysics Data System (ADS)

    Moravcsik, Michael J.; Arash, Firooz; Goldstein, Gary R.

    1985-04-01

    Recent polarization data on proton-proton elastic scattering at 800 MeV taken at LAMPF are used for an amplitude analysis using the optimal formalism. The direct analysis of data is done in the transversity frame, which is best suited to parity-conserving reactions. From the results, amplitudes are also obtained in the helicity frame and the ``magic'' frame. Agreement with previous amplitudes obtained from an energy-dependent phase-shift analysis is good. The comparison of the helicity amplitudes c and e strengthens previous suggestions for a possible triplet-state dibaryon resonance. The comparison of the amplitudes am and cm in the magic frame indicates a possible domination of the process near 90° scattering angle by one-particle-exchange mechanism involving exchanged particles with natural parity.

  3. Elastic positron-cadmium scattering at low energies

    SciTech Connect

    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.

  4. Nuclear rainbow in elastic scattering of {sup 9}Be nuclei

    SciTech Connect

    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.

  5. Microcalcifications as elastic scatterers under ultrasound.

    PubMed

    Anderson, M E; Soo, M C; Trahey, G E

    1998-01-01

    One of the fundamental limitations of medical ultrasound in the imaging of the breast is the inability of current practice to reliably visualize microcalcifications in the size range of clinical interest. Microcalcifications (MCs) are small crystals of calcium phosphates that form in human tissue through a number of mechanisms. The size, morphology, and distribution of MCs are important indicators in the mammographic screening for and diagnosis of various carcinomas in the breast. The authors are investigating the imaging of MCs under ultrasound in the interest of extending the utility of medical ultrasound in the breast clinic. They present an analysis of the acoustic properties of MCs modeled as elastic spheres based on the Faran model that considers the predicted complex spectra and spatial coherence of echoes from MCs. They have found the predictions of the model to be similar to ultrasound echoes from suspected MCs in vivo. They also present breast phase aberration estimates and spatial and frequency compounding results based on the echoes from these targets. PMID:18244247

  6. Measurements of the Proton Electromagnetic Form Factor Ratio From Elastic e + p -> e + p Scattering at Momentum Transfer Q2 = 2.5, 5.2, 6.7 and 8.5 (GeV/c)2

    SciTech Connect

    Mkrtchyan, Arthur

    2012-05-31

    Among the fundamental observables of nucleon structure, electromagnetic form factors are a crucial benchmark for modern calculations describing the strong interaction dynamics of the nucleon's quark constituents. Electromagnetic probes are traditionally preferered to the hadronic beams. The electromagnetic interaction is a powerful tool for investigating the nucleon structure since it is well understood and it reveals observables that can be directly interpreted in terms of the current carried by the quarks. Elastic scattering leads to the form factors that describe the spatial charge and current distributions inside the nucleon. The reaction mechanism is assumed to be one photon exchange, the electromagnetic interaction is exactly calculable in QED, and one can safely extract the information on the hadronic vertex. The most important feature of early measurements of proton form factor ratio GEp/GMp with recoil polarization technique at Q2 up to 5.6 (GeV/c)2 is the sharp decline of the ratio with Q2 increases, indicating that GEp falls much faster than GMp. This contradicts to data obtained by Rosenbluth separation method. An intriguing question was whether GEp will continue to decrease or become constant when Q2 increases. New set of measurements of proton form factor ratio GEp/GMp at Q2 = 2.5, 5.2, 6.7 and 8.5 (GeV/c)2 have been conducted at JLab Hall C using ~85% longitudinally polarized electron elastic scattering from unpolarized hydrogen target. Recoil protons were detected in the HMS magnetic spectrometer with the standard detector package, combined with newly installed trigger scintillators and Focal Plane Polarimeter. The BigCal electromagnetic calorimeter (1744 channel) have been used for electron detection. Data obtained in this

  7. Investigation of color transparency by high transverse momentum pp elastic scattering inside nuclei

    SciTech Connect

    Barton, D.S.; Bunce, G.; Carroll, A.S.; Gushue, S.; Makdisi, Y.I.; Heppelmann, S.; Courant, H.; Fang, G.Y.; Heller, K.J.; Marshak, M.L.

    1989-01-01

    Following a suggestion of Mueller and Brodsky, we have measured (p, 2p) quasielastic scattering in nuclei at 90(degree) CM at momentum transfers of Q/sup 2/ = 4.8, 8.5 and 10.4 (GeV/c)/sup 2/. In a perturbative QCD model of large transverse momentum exclusive reactions, the hadrons which scatter are anomalously ''small,'' and hence have a reduced absorption in nuclear matter over distances comparable to nuclear radii. At sufficiently high momentum, the absorption should vanish completely and lead to complete ''color transparency.'' The absorption of the initial and final state protons as they pass through nuclear matter is determined from the ratio of the differential cross section for elastic scattering from protons in nuclei to that from free protons. The kinematic constraints of the experiment allow a clear extraction of the (p,2p) quasielastic signal, and a good measurement of the target proton momentum spectrum as probed by large momentum transfers. In contrast to a conventional Glauber picture of constant transparency, a striking energy dependence is observed in this experiment. 11 refs., 4 figs.

  8. 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.

  9. Semiphenomenological method of analysis for intermediate-energy alpha-nucleus elastic scattering data

    SciTech Connect

    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.

  10. Measurement of Neutrino-Nucleon Neutral-Current Elastic Scattering Cross-section at SciBooNE

    SciTech Connect

    Takei, Hideyuki; /Tokyo Inst. Tech.

    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{sub A}(Q{sup 2}) as well as electromagnetic form factors unlike electromagnetic interaction. G{sub A} is propotional to strange part of nucleon spin ({Delta}s) in Q{sup 2} {yields} 0 limit. Measurement of NC elastic cross-section with smaller Q{sup 2} enables us to access {Delta}s. 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{sup 2} > 0.4 GeV{sup 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 {nu}p {yields} {nu}p process, the recoil proton is detected. On the other hand, most of {nu}n {yields} {nu

  11. 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.

  12. Measurement of neutrino flux from neutrino-electron elastic scattering

    DOE PAGESBeta

    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

  13. Target structure independent 7Li elastic scattering at lowmomentum transfers

    SciTech Connect

    Momotyuk, O.A.; Keeley, N.; Kemper, K.W.; Roeder, B.T.; Crisp,A.M.; Cluff, W.; Schmidt, B.G.; Wiedeking, M.; Marechal, F.; Rusek, K.; Mezhevych, S.Yu.; Liendo, J.

    2006-07-20

    Analyzing powers and cross sections for the elastic scattering of polarized 7Li by targets of 6Li, 7Li and 12C are shown to depend only on the properties of the projectile for momentum transfers of less than 1.0 fm-1. The result of a detailed analysis of the experimental data within the framework of the coupled channels model with ground state reorientation and transitions to the excited states of the projectile and targets included in the coupling schemes are presented. This work suggests that nuclear properties of weakly-bound nuclei can be tested by elastic scattering experiments, independent of the target used, if data are acquired for momentum transfers less than {approx}1.0 fm-1.

  14. 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.

  15. Visualization of scattering strength of elastic bodies in a fluid

    NASA Astrophysics Data System (ADS)

    Schenck, H. A.; Fales, J. L.

    1992-07-01

    As Part of the Submarine Technology Program, the Defense Advanced Research Projects Agency (DARPA) recently sponsored a Low-Frequency Structural Acoustics Benchmark Exercise. The purpose of the exercise was to test and validate several major computational codes that have been developed to solve acoustic scattering problems of elastic objects in a fluid. This report describes some of the visualization techniques and procedures that were developed to review, compare, and analyze the large amount of computational data generated in the exercise.

  16. Elasticity of biomembranes studied by dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Fujime, Satoru; Miyamoto, Shigeaki

    1991-05-01

    Combination of osmotic swelling and dynamic light scattering makes it possible to measure the elastic modulus of biomembranes. By this technique we have observed a drastic increase in membrane flexibility on activation of Na/glucose cotransporters in membrane vesicles prepared from brush-borders of rat small intestine and on activation by micromolar [Ca2] of exocytosis in secretory granules isolated from rat pancreatic acinar cells and bovine adrenal chromaffin cells. 1 .

  17. 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

  18. Experiment to measure total cross sections, differential cross sections and polarization effects in pp elastic scattering at RHIC

    SciTech Connect

    Guryn, W.

    1998-02-01

    The authors are describing an experiment to study proton-proton (pp) elastic scattering experiment at the Relativistic Heavy Ion Collider (RHIC). Using both polarized and unpolarized beams, the experiment will study pp elastic scattering from {radical}s = 50 GeV to {radical}s = 500 GeV in two kinematical regions. In the Coulomb Nuclear Interference (CNI) region, 0.0005 < {vert_bar}t{vert_bar} < 0.12 (GeV/c){sup 2}, they will measure and study the s dependence of the total and elastic cross sections, {sigma}{sub tot} and {sigma}{sub el}; the ratio of the real to the imaginary part of the forward elastic scattering amplitude, {rho}; and the nuclear slope parameter of the pp elastic scattering, b. In the medium {vert_bar}t{vert_bar}-region, {vert_bar}t{vert_bar} < 1.5 (GeV/c){sup 2}, they plan to study the evolution of the dip structure with s, as observed at ISR in the differential elastic cross section, d{sigma}{sub el}/dt, and the s and {vert_bar}t{vert_bar} dependence of b. With the polarized beams the following can be measured: the difference in the total cross sections as function of initial transverse spin states {Delta}{sigma}{sub T}, the analyzing power, A{sub N}, and the transverse spin correlation parameter A{sub NN}. The behavior of the analyzing power A{sub N} at RHIC energies in the dip region of d{sigma}{sub el}/dt, where a pronounced structure was found at fixed-target experiments will be studied. The relation of pp elastic scattering to the beam polarization measurement at RHIC is also discussed.

  19. 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.

  20. 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.

  1. Deconstruction and elastic {pi}{pi} scattering in Higgsless models

    SciTech Connect

    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.

  2. Elastic waves in discontinuous media: Three-dimensional scattering

    NASA Astrophysics Data System (ADS)

    Molino, F. R.; Sabatier, P. C.

    1994-09-01

    This report contains an exact study of elastic wave propagation and its scattering in discontinuous media where hard reflectors are onionlike sets of surfaces. In order to reformulate the problem as a finite set of boundary integral equations, the wave motion between reflectors is represented by means of elastic potentials which involve vectorial densities on the surfaces. In the external medium, an outgoing asymptotic condition generalizes the Silver-Müller (and the Sommerfeld) condition to the case of coupled waves (S and P waves) moving with different velocities. The uniqueness of the Green's function, which guarantees the uniqueness of the direct problem solution, is proven. For any incident wave and arbitrary number of surfaces, the transmission and scattering problems are studied, with and without the simplification obtained by assuming constant Poisson ratios. According to the parameter ranges, the equations which are obtained are well posed, either as second kind Fredholm equations, or because they reduce to the inverse of the sum of the identity operator and a ``small norm'' bounded operator. The results can be used to describe rigorously the three-dimensional scattering of elastic waves in the frequency domain for any kind of incident wave function (P,S,...) as well as the response to a localized source.

  3. Shallow Lunar Hydrogen and Forward-Scattered Albedo Protons

    NASA Astrophysics Data System (ADS)

    Wilson, J. K.; Schwadron, N.; Jordan, A. P.; Spence, H. E.; Looper, M. D.; Townsend, L. W.

    2015-11-01

    The CRaTER instrument sees a ~40% higher flux of lunar albedo protons (>65 MeV) at grazing angles compared to the nadir direction. A shallow layer (<10 cm) of hydrated lunar regolith may enhance the yield of forward-scattered albedo protons.

  4. Angularly-resolved elastic light scattering of micro-particles

    NASA Astrophysics Data System (ADS)

    Aptowicz, Kevin B.

    From microbiology to astrophysics, the scientific community has long embraced elastic light scattering from small particles as a diagnostic tool. Elastic light scattering has an extremely large scattering cross-section, allowing for single particle interrogation. This is critical in applications where trace amounts of suspect particles are to be detected in a diverse background of natural aerosols. By angularly-resolving the elastically scattered light, features can be detected in these patterns that are sensitive to a particle's morphology (shape, size, internal structure, and composition). An apparatus to collect LA TAOS (Large-Angle Two-dimensional Angular Optical Scattering) patterns from single particles in-situ and in real-time was designed and constructed. The setup utilizes a cross-beam trigger system to minimize the effects of the aberration coma stemming from the main collection optic, an ellipsoidal mirror. LA TAOS patterns of ambient aerosols were collected and analyzed. Approximately 15% of the ambient aerosol had a sphere-like shape. The refractive index of these spheres was estimated by curve-fitting to Lorenz-Mie theory. In addition, the island features prevalent in the LA TAOS pattern were analyzed. Metrics generated from these were used to get partial discrimination between clusters of Bacillus subtilis spores (a simulant for anthrax) and aerosol particles found in the ambient atmosphere. A novel experimental setup for collecting simultaneously LA TAOS patterns at two wavelengths in the mid-infrared was also implemented. With this setup, the relative strength of single-particle absorption could be discerned at the two illuminating wavelengths.

  5. Elastic Properties of Lithium Germanate Glasses Studied by Brillouin Scattering

    NASA Astrophysics Data System (ADS)

    Kaneda, Kazuhiro; Matsuda, Yu; Kojima, Seiji

    2010-07-01

    To investigate the correlation between structural changes and physical properties, the elastic properties of lithium germanate glasses, xLi2O·(100-x)GeO2 represented as a function of Li2O mole fraction, have been studied in the composition range 6≤x≤36 mol % by Brillouin scattering spectroscopy. Raman spectra have also been measured to clarify the composition variation of structural changes. Several elastic properties, such as sound velocity and elastic modulus, have been determined from the Brillouin shift. The longitudinal and transverse sound velocities increase up to about x=20 mol %, and above x=20 mol %, they become nearly constant. Elastic moduli, such as longitudinal modulus (L) and shear modulus (G), increase gradually up to x=22 mol % and then decrease with a further increase in Li2O content. It is considered that such behaviors are due to the change in the coordination number of germanium atoms and the formation of nonbridging oxygen. Differently from other elastic moduli, Poisson's ratio (σ) shows a similar behavior to sound velocity.

  6. 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

  7. Measuring the 2-gamma Exchange Effect in Electron-Proton Scattering at CLAS

    SciTech Connect

    Bennett, Robert

    2011-10-01

    Recent results from experiments at Jefferson Laboratory, Newport News VA, which measure the ratio of the electric to magnetic form factors of the proton, G{sub E}/G{sub M}, have forced us to reexamine the single photon exchange approximation in lepton-proton elastic scattering. Discrepancies between the ratio obtained via the time-tested Rosenbluth separation method and new polarization transfer measurements, which differ by as much as a factor of three, may be resolved by considering the effect of two photon exchange (TPE). Theoretical corrections for the TPE effect are difficult due to the large number of excited nucleon states that can contribute to the process. The TPE effect can, however, be determined directly by measuring the ratio of the positron-proton to electron-proton elastic scattering cross sections, R = {sigma}(e{sup +})/{sigma}(e{sup -}), since the TPE effect changes sign with the charge of the incident particle. The CLAS TPE experiment at Jefferson Laboratory, will determine the effect of two-photon exchange in elastic lepton-proton scattering by precisely measuring the ratio of positron-proton to electron-proton elastic cross sections over a large kinematic range (0.1 < {var_epsilon} < 0.96, 0.02 {le} Q{sup 2} {le} 2.0). We will accomplish this by directing the 5.5 GeV primary electron beam, provided by the Continuous Electron Beam Accelerator Facility (CEBAF), onto a set of radiators and converters to produce simultaneous and identical beams of electron and positrons. Acceptance and efficiency concerns are minimized by only considering the ratios of the elastic cross sections and switching polarity of magnets in the beam line and the spectrometer. Guided by the results of a short 2006 test run and extensive GEANT based modeling, new shielding and beam line components were designed to maximize luminosity. The unique experimental design and challenges of the TPE experiment and the projected luminosities will be presented.

  8. {Delta} resonance contribution to two-photon exchange in electron-proton scattering

    SciTech Connect

    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.

  9. Effect of repulsive and attractive three-body forces on nucleus-nucleus elastic scattering

    SciTech Connect

    Furumoto, T.; Sakuragi, Y.; Yamamoto, Y.

    2009-10-15

    The effect of the three-body force (TBF) is studied in nucleus-nucleus elastic scattering on the basis of Brueckner theory for nucleon-nucleon (NN) effective interaction (complex G matrix) in the nuclear matter. A new G matrix called CEG07 proposed recently by the present authors includes the TBF effect and reproduces a realistic saturation curve in the nuclear matter, and it is shown to well reproduce proton-nucleus elastic scattering. The microscopic optical potential for the nucleus-nucleus system is obtained by folding the G matrix with nucleon density distributions in colliding nuclei. We first analyze in detail the {sup 16}O+{sup 16}O elastic scattering at E/A=70 MeV. The observed cross sections are nicely reproduced up to the most backward scattering angles only when the TBF effect is included. The use of the frozen-density approximation (FDA) is essentially important to properly estimate the effect of the TBF in nucleus-nucleus scattering. Other prescriptions for defining the local density have also been tested, but only the FDA prescription gives a proper description of the experimental cross sections as well as the effect of the TBF. The effects of the three-body attraction and the {omega}-rearrangement term are also analyzed. The CEG07 interaction is compared with CDM3Y6, which is a reliable and successful effective density-dependent NN interaction used in the double-folding model. The CEG07 G matrix is also tested in the elastic scattering of {sup 16}O by the {sup 12}C, {sup 28}Si, and {sup 40}Ca targets at E/A=93.9 MeV, and in the elastic scattering of {sup 12}C by the {sup 12}C target at E/A=135 MeV with great success. The decisive effect of the TBF is clearly seen also in those systems. Finally, we have tested CEG07a, CEG07b, and CEG07c for the {sup 16}O+{sup 16}O system at various energies.

  10. Elastic scattering measurements for {sup 7}Be+{sup 27}Al system at RIBRAS facility

    SciTech Connect

    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.

  11. 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.

  12. Consistency of electron scattering data with a small proton radius

    NASA Astrophysics Data System (ADS)

    Griffioen, Keith; Carlson, Carl; Maddox, Sarah

    2016-06-01

    We determine the charge radius of the proton by analyzing the published low momentum transfer electron-proton scattering data from Mainz. We note that polynomial expansions of the form factor converge for momentum transfers squared below 4 mπ2 , where mπ is the pion mass. Expansions with enough terms to fit the data, but few enough not to overfit, yield proton radii smaller than the CODATA or Mainz values and in accord with the muonic atom results. We also comment on analyses using a wider range of data, and overall obtain a proton radius RE=0.840 (16 ) fm.

  13. Proton-proton Scattering Above 3 GeV/c

    SciTech Connect

    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.

  14. A Microscopic Optical Potential Approach to {sup 6,8}He+p Elastic Scattering

    SciTech Connect

    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.

  15. 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.

  16. Studies of toxic aerosols via elastic and inelastic light scattering

    SciTech Connect

    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.

  17. Overview of single-cell elastic light scattering techniques.

    PubMed

    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. PMID:25760756

  18. Elastic scattering of electrons from singly ionized argon

    SciTech Connect

    Griffin, D.C.; Pindzola, M.S.

    1996-03-01

    Recently, Greenwood {ital et} {ital al}. [Phys. Rev. Lett. {bold 75}, 1062 (1995)] reported measurements of large-angle elastic scattering of electrons from singly ionized argon at an energy of 3.3 eV. They compared their results for the differential cross section with cross sections determined using phase shifts obtained from two different scattering potentials and found large discrepancies between theory and experiment at large angles. They state that these differences may be due to the effects of polarization of the target, which are not included in their calculations, as well as inaccurate representations of electron exchange in the local scattering potentials that are employed to determine the phase shifts. In order to test these proposed explanations of the discrepancies, we have carried out calculations of elastic scattering from Ar{sup +} using the {ital R}-matrix method. We compare both a single-state calculation, which does not include polarization, and a 17-state calculation, in which the effects of dipole polarizability are included through the use of polarization pseudostates within the close-coupling expansion, to each other and with the measurements. We find some differences between the two calculations at intermediate scattering angles, but very close agreement at angles above 100{degree}. Although the calculated cross sections agree with experiment between 120{degree} and 135{degree}, large discrepancies persist at angles above 135{degree}. We conclude that the differences between the measurements and theory cannot be explained on the basis of an inaccurate representation of electron exchange or polarization of the target. {copyright} {ital 1996 The American Physical Society.}

  19. 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.

  20. About multiple scattering of high energy protons in crystal deflectors

    NASA Astrophysics Data System (ADS)

    Taratin, A. M.; Scandale, W.

    2015-07-01

    The process of multiple scattering of high energy protons in a silicon crystal at its amorphous orientation was studied by simulation of proton trajectories in the model of binary collisions and by a straight simulation of the sequences of proton collisions with atoms when their impact parameters are randomly and uniformly distributed on the symmetry cell for a given crystallography direction. The value of the RMS deflection of multiple scattering obtained by the simulation is in a good agreement with the experiment and more than 15% larger than it follows from the Moliere theory. The obtained RMS deflection used in the Gaussian approach of multiple scattering well describes dechanneling of protons in the frame of the planar potential model. Different number of proton collisions with atoms occurs along the same crystal length for different crystal orientations. However, the change of the collision number is compensated by the corresponding change of the mean square deflection in a single collision. Therefore, multiple scattering is the same for different crystal orientations. The generator of multiple scattering for amorphous crystal orientations was proposed.

  1. Proton radiography, nuclear cross sections and multiple scattering

    NASA Astrophysics Data System (ADS)

    Sjue, Sky; Lansce Proton Radiography Team

    2015-10-01

    Proton radiography is a valuable tool for assessing dynamic experiments over times as short as 100 nanoseconds. Facilities now exist or are in development in the China, Germany, Russia and the United States with proton energies ranging from 800 MeV to 50 GeV. The multiple Coulomb scattering distribution of protons and the cross sections for proton interactions with the nucleus both depend on the proton energy. A detailed understanding of these effects is necessary to gain the best possible quantitative information from proton generated radiographs. We will present an analysis of the integrated nuclear cross sections for various metals at 800 MeV kinetic energy using step wedges at Los Alamos Neutron Science Center at 800 MeV, along with results at 24 GeV from Alternating Gradient Synchrotron at 24 GeV. The results will be compared with models of multiple scattering and several models of the nuclear interactions. Finally, we will discuss trends in the interplay between nuclear attenuation and multiple scattering as a function of proton energy.

  2. Elastic Scattering of Electron Vortex Beams in Magnetic Matter

    NASA Astrophysics Data System (ADS)

    Edström, Alexander; Lubk, Axel; Rusz, Ján

    2016-03-01

    Elastic scattering of electron vortex beams on magnetic materials leads to a weak magnetic contrast due to Zeeman interaction of orbital angular momentum of the beam with magnetic fields in the sample. The magnetic signal manifests itself as a redistribution of intensity in diffraction patterns due to a change of sign of the orbital angular momentum of the electron vortex beam. While in the atomic resolution regime the magnetic signal is most likely under the detection limits of present transmission electron microscopes, for electron probes with high orbital angular momenta, and correspondingly larger spatial extent, its detection is predicted to be feasible.

  3. Proton beam scattering system optimization for clinical and research applications

    SciTech Connect

    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.

  4. cap alpha. /sup 4/He elastic scattering at high energies

    SciTech Connect

    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.

  5. Elastic scattering of low-energy electrons from toluene

    NASA Astrophysics Data System (ADS)

    Sakaamini, Ahmad; Hargreaves, L. R.; Khakoo, M. A.; Pastega, D. F.; Bettega, M. H. F.

    2016-04-01

    Theoretical and normalized experimental differential, momentum transfer, and integral cross sections for vibrationally elastic scattering of low-energy electrons from toluene (C6H5C H3 ) are presented. The differential cross sections are measured at incident energies from 1 to 20 eV and scattering angles from 15° to 130°. The calculated cross sections are obtained using the Schwinger multichannel method with pseudopotentials in the static-exchange plus polarization approximation. Comparisons are made between the present theory and measurements with earlier available measurements. In general, the agreement between the theory and the experiment is very good. We also discuss the resonance spectra of toluene, where we find three π* shape resonances whose locations agree well with the experiment. In addition, we compare the cross sections of toluene and benzene, since the former can be considered as a benzene derivative by the substitution of a hydrogen in benzene by a C H3 group in toluene.

  6. Elastic scattering of Beryllium isotopes near the Coulomb barrier

    SciTech Connect

    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.

  7. High Precision Measurement of the Proton Elastic Form Factor Ratio at Low Q2

    SciTech Connect

    Zhan, Xiaohui

    2010-01-01

    Experiment E08-007 measured the proton elastic form factor ratio μpGE/GM in the range of Q2 = 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 Q2 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 GEp 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.

  8. Inclusive proton spectra and total reaction cross sections for proton-nucleus scattering at 800 MeV

    SciTech Connect

    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.

  9. Experiment to measure total cross sections, differential cross sections and polarization effects in pp elastic scattering at RHIC

    SciTech Connect

    Guryn, W.

    1995-12-31

    The author is describing an experiment to study proton-proton (pp) elastic scattering experiment at the Relativistic Heavy Ion Collider (RHIC). Using both polarized and unpolarized beams, the experiment will study pp elastic scattering from {radical}s = 60 GeV to {radical}s = 500 GeV in two kinematical regions .In the Coulomb Nuclear Interference (CNI) region, 0.0005 < {vert_bar}t{vert_bar} < 0.12 (GeV/c){sup 2}, we will measure and study the s dependence of the total and elastic cross sections, {sigma}{sub tot} and {sigma}{sub el}; the ratio of the real to the imaginary part of the forward elastic scattering amplitude, {rho}; and the nuclear slope parameter of the pp elastic scattering, b. In the medium {vert_bar}t{vert_bar}, {vert_bar}t{vert_bar} {le} 1.5 (GeV/c){sup 2}, we plan to study the evolution of the dip structure with s, as observed at ISR in the differential elastic cross section, d{sigma}{sub el}/dt, and the s and {vert_bar}t{vert_bar} dependence of b. With the polarized beams the following can be measured: the difference in the total cross sections as function of initial transverse spin stated {Delta}{sigma}{sub T}, the analyzing power, A{sub N}, and the transverse spin correlation parameter A{sub NN}. The behavior of the analyzing power A{sub N} at RHIC energies in the dip region of d{sigma}{sub el}/dt, where a pronounced structure was found at fixed-target experiments will be studied.

  10. Radiative corrections to the elastic e-p and mu-p scattering in Monte Carlo simulation approach

    NASA Astrophysics Data System (ADS)

    Koshchii, Oleksandr; Afanasev, Andrei; MUSE Collaboration

    2015-04-01

    In this paper, we calculated exactly lepton mass corrections for the elastic e-p and mu-p scatterings using the ELRADGEN 2.1 Monte Carlo generator. These estimations are essential to be used in the MUSE experiment that is designed to solve the proton radius puzzle. This puzzle is due to the fact that two methods of measuring proton radius (the spectroscopy method, which measures proton energy levels in hydrogen, and the electron scattering experiment) predicted the radius to be 0.8768 +/-0.0069 fm, whereas the experiment that used muonic hydrogen provided the value that is 5% smaller. Since the radiative corrections are different for electrons and muons due to their mass difference, these corrections are extremely important for analysis and interpretation of upcoming MUSE data.

  11. 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.

  12. Elastic Neutron Scattering at 96 MeV

    SciTech Connect

    Hildebrand, A.; Blomgren, J.; Atac, A.; Bergenwall, B.; Johansson, C.; Klug, J.; Mermod, P.; Nilsson, L.; Pomp, S.; Esterlund, M.; Dangtip, S.; Tippawan, U.; Phansuke, P.; Jonsson, O.; Renberg, P.-U.; Prokofiev, A.; Nadel-Turonski, P.; Elmgren, K.; Olsson, N.; Blideanu, V.

    2005-05-24

    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 deg. 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.

  13. Low energy elastic electron scattering from CF3Br molecules.

    PubMed

    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

  14. Polarisation Transfer in Proton Compton Scattering at High Momentum Transfer

    SciTech Connect

    Hamilton, David

    2004-12-31

    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 (~ 0 ~ 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.

  15. Neutron transition densities for 48Ca from proton scattering at 200 and 318 MeV

    NASA Astrophysics Data System (ADS)

    Feldman, A. E.; Kelly, J. J.; Flanders, B. S.; Khandaker, M. A.; Seifert, H.; Boberg, P.; Hyman, S. D.; Karen, P. H.; Norum, B. E.; Welch, P.; Chen, Q.; Bacher, A. D.; Berg, G. P.; Stephenson, E. J.; Nanda, S.; Saha, A.; Scott, A.

    1994-04-01

    Differential cross sections and analyzing powers for scattering of 200 and 318 MeV protons have been measured for states of 48Ca up to 7 MeV of excitation. The data cover c.m. momentum transfers from approximately 0.4 to 3.0 fm-1. Neutron transition densities were extracted for the 2+1,3-1,3-2,4+2, and 5-1 states using density-dependent empirical effective interactions previously calibrated upon elastic and inelastic scattering data for 16O and 40Ca. The corresponding proton transition densities were obtained from electron scattering data and held fixed during the analysis. Fits performed to the data for either energy provide excellent predictions for the other. Neutron densities fitted to data for either energy independently agree very well with each other and with the densities fitted to both data sets simultaneously. These densities are also consistent with earlier data for 500 MeV protons. The energy-independence of the extracted transition densities demonstrates that residual errors in the reaction model are compatible with the error bands estimated by the fitting procedure. Several additional tests of the model dependence of the results were performed also. The proton and neutron transition densities are compared with calculations based upon the extended random phase approximation, which includes 2p2h correlations. These calculations are most successful for densities dominated by 1p1h configurations, whereas densities requiring substantial 2p2h contributions tend to be underestimated.

  16. Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data

    NASA Astrophysics Data System (ADS)

    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.; CLAS Collaboration

    2015-02-01

    There is a significant discrepancy between the values of the proton electric form factor, GEp, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of GEp 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 (ɛ ) and momentum transfer (Q2) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ɛ 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 Δ intermediate states, which have been shown to resolve the discrepancy up to 2 - 3 GeV2 .

  17. Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data

    SciTech Connect

    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.

  18. Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data

    SciTech Connect

    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.

  19. Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data

    DOE PAGESBeta

    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

  20. Towards a resolution of the proton form factor problem: new electron and positron scattering data.

    PubMed

    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). PMID:25723209

  1. Polarization Transfer in Proton Compton Scattering at High Momentum Transfer

    SciTech Connect

    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.

  2. Polarization Transfer in Proton Compton Scattering at High Momentum Transfer

    SciTech Connect

    D.J. Hamilton; Vahe Mamyan

    2004-10-01

    Compton scattering from the proton was investigated at s = 6.9 GeV{sup 2} and t = -4.0 TeV{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 excellent agreement with a prediction based on a reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton and in disagreement with a prediction of pQCD based on a two-gluon exchange mechanism.

  3. Signal sources in elastic light scattering by biological cells and tissues: what can elastic light scattering spectroscopy tell us?

    NASA Astrophysics Data System (ADS)

    Xu, M.; Wu, Tao T.; Qu, Jianan Y.

    2008-02-01

    We used a unified Mie and fractal model to analyze elastic light spectroscopy of cell suspensions to obtain the size distributions of cells and nuclei, their refractive indices, and the background refractive index fluctuation inside the cell, for different types of cells, including human cervical squamous carcinoma epithelial (SiHa) cells, androgen-independent malignant rat prostate carcinoma epithelial (AT3.1) cells, non-tumorigenic fibroblast (Rat1p) cells in the plateau phase of growth, and tumorigenic fibroblast (Rat1-T1E) cells in the exponential phase of growth. Signal sources contributing to the scattering (μs) and reduced scattering (μ 's) coefficients for these cells of various types or at different growth stages are compared. It is shown that the contribution to μ s from the nucleus is much more important than that from the background refractive index fluctuation. This trend is more significant with increase of the probing wavelength. On the other hand, the background refractive index fluctuation overtakes the nucleus and may even dominate in the contribution to reduced scattering. The implications of the above findings on biomedical light scattering techniques are discussed.

  4. Determination of the cervical transformation zone using elastic-scattering spectroscopy

    SciTech Connect

    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.

  5. 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.

  6. Derivation of breakup probabilities of weakly bound nuclei from experimental elastic and quasi-elastic scattering angular distributions

    NASA Astrophysics Data System (ADS)

    Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.; Diaz-Torres, A.; Gomes, P. R. S.; Lenske, H.

    2015-11-01

    We present a simple method to derive breakup probabilities of weakly bound nuclei by measuring only elastic (or quasi-elastic) scattering for the system under investigation and a similar tightly bound system. When transfer followed by breakup is an important process, one can derive only the sum of breakup and transfer probabilities.

  7. Detection of point-like scatterers using one type of scattered elastic waves

    PubMed Central

    Gintides, Drossos; Sini, Mourad; Thành, Nguyen Trung

    2012-01-01

    In this paper, we are concerned with the detection of point-like obstacles using elastic waves. We show that one type of waves, either the P or the S scattered waves, is enough for localizing the points. We also show how the use of S incident waves gives better resolution than the P waves. These affirmations are demonstrated by several numerical examples using a MUSIC type algorithm. PMID:22308060

  8. Limits on dark matter proton scattering from neutrino telescopes using micrOMEGAs

    SciTech Connect

    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.

  9. 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.

  10. np Elastic-scattering experiments with polarized neutron beams

    SciTech Connect

    Chalmers, J.S.; Ditzler, W.R.; Hill, D.; Hoftiezer, J.; Johnson, K.; Shima, T.; Shimizu, H.; Spinka, H.; Stanek, R.; Underwood, D.

    1985-01-01

    Measurements of the spin transfer parameters, K/sub NN/ and K/sub LL/, at 500, 650, and 800 MeV are presented for the reaction p-vector d ..-->.. n-vector pp at 0/sup 0/. The data are useful input to the NN data base and indicate that the quasi-free charge exchange (CEX) reaction is a useful mechanism for producing neutrons with at least 40% polarization at energies as low as 500 MeV. Measurements of np elastic scattering observables C/sub LL/ and C/sub SL/ covering 35/sup 0/ to 172/sup 0/ are performed using a polarized neutron beam at 500, 650, and 800 MeV. Preliminary results are presented. 3 refs., 6 figs.

  11. np elastic scattering analyzing power characteristics at intermediate energies

    SciTech Connect

    Abegg, R.; Ahmad, M.; Bandyopadhyay, D.; Birchall, J.; Cairns, E.B.; Chantziantoniou, K.; Coombes, G.H.; Davis, C.A.; Davison, N.E.; Delheij, P.P.J.; Green, P.W.; Greeniaus, L.G.; Gubler, H.P.; Healey, D.C.; Lapointe, C.; Lee, W.P.; McDonald, W.J.; Miller, C.A.; Moss, G.A.; Page, S.A.; Plattner, G.R.; Poffenberger, P.R.; Ramsay, W.D.; Rodning, N.L.; Roy, G.; Soukup, J.; Svenne, J.P.; Tkachuk, R.R.; van Oers, W.T.H.; Wait, G.D.; Watson, J.W.; Ye, Y.; Zhang, Y.P. University of Manitoba, Department of Physics, Winnipeg, Manitoba, Canada R3T 2N2 University of Alberta, Department of Physics, Edmonton, Alberta, Canada T6G 2N5 University of Basel, Institute of Physics, CH-4000 Basel, Switzerland Kent State University, Department of Physics, Kent, Ohio 44242)

    1989-11-01

    Recent measurements of charge symmetry breaking in the {ital np} system at 477 MeV, and of {ital A}{sub 00{ital nn}} for {ital np} elastic scattering at 220, 325, and 425 MeV also yield accurate analyzing power data. These data allow the energy dependence of the analyzing power zero-crossing angle and the slope of the analyzing power at the zero-crossing angle to be determined. The incident neutron energies span a region where the zero-crossing angle is strongly energy dependent ({ital E}{sub {ital n}}{lt}250 MeV) to where it is almost independent of energy ({ital E}{sub {ital n}}{gt}350 MeV). The results are compared to current phase-shift analysis predictions, recently published data, and the predictions of the Bonn and Paris potentials.

  12. 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.

  13. Innovative wavelet protocols in analyzing elastic incoherent neutron scattering.

    PubMed

    Magazù, S; Migliardo, F; Caccamo, M T

    2012-08-01

    Wavelet analysis has recently found a wide range of applications in Physics, Mathematics, and signal processing. This is mainly due to its ability to locally resolve a nonstationary signal in terms of functional forms, called mother wavelets, and to firmly locate trend anomalies in the signal. In the present paper, some examples of the application of wavelet analysis to elastic incoherent neutron scattering (EINS) data collected by the IN13 spectrometer at the Institute Laue Langevin (ILL) on water mixtures of the three homologous disaccharides, trehalose, maltose, and sucrose, and on literature data of dry and hydrated lysozyme and myoglobine as a function of temperature and of exchanged wave vector are presented. The experimental findings have been analyzed by means of a wavelet analysis that allows one to characterize the scattered elastic intensity behavior on different scales and to locate the discontinuities and the trend anomalies in the registered signal. This latter procedure is made possible thanks to the multiscale analysis, which allows, by decreasing the scale, one to localize the peculiar trend features. The entire body of the experimental findings reveals different transition temperatures for the three investigated disaccharides together with a stronger temperature dependence of the maltose/H(2)O and sucrose/H(2)O systems in comparison with the trehalose/H(2)O mixture, which signals a stronger character of this latter in comparison with the other two homologous disaccharides. These results justify the better ability of trehalose, with respect to maltose and sucrose, to encapsulate biostructures in a more rigid matrix. PMID:22793379

  14. Low-energy elastic electron scattering from furan

    SciTech Connect

    Khakoo, M. A.; Muse, J.; Ralphs, K.; Costa, R. F.; Bettega, M. H. F.; Lima, M. A. P.

    2010-06-15

    We report normalized experimental and theoretical differential cross sections for elastic electron scattering by C{sub 4}H{sub 4}O (furan) molecules from a collaborative project between several Brazilian theoretical groups and an experimental group at California State Fullerton, USA. The measurements are obtained by using the relative flow method with helium as the standard gas and a thin aperture target gas collimating source. The relative flow method is applied without the restriction imposed by the relative flow pressure condition on helium and the unknown gas. The experimental data were taken at incident electron energies of 1, 1.5, 1.73, 2, 2.7, 3, 5, 7, 10, 20, 30, and 50 eV and covered the angular range between 10 deg. and 130 deg. The measurements verify observed {pi}* shape resonances at 1.65{+-}0.05eV and 3.10{+-}0.05 eV scattering energies, in good agreement with the transmission electron data of Modelli and Burrow [J. Phys. Chem. A 108, 5721 (2004)]. Furthermore, the present results also indicated both resonances dominantly in the d-wave channel. The differential cross sections are integrated in the standard way to obtain integral elastic cross sections and momentum transfer cross sections. The calculations employed the Schwinger multichannel method with pseudopotentials and were performed in the static-exchange and in the static-exchange plus polarization approximations. The calculated integral and momentum transfer cross sections clearly revealed the presence of two shape resonances located at 1.95 and 3.56 eV and ascribed to the B{sub 1} and A{sub 2} symmetries of the C{sub 2v} point group, respectively, in very good agreement with the experimental findings. Overall agreement between theory and experiment regarding the differential, momentum transfer, and integral cross sections is very good, especially for energies below 10 eV.

  15. Nuclear Microprobe using Elastic Recoil Detection (ERD) for Hydrogen Profiling in High Temperature Protonic Conductors

    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.

  16. Gamow shell model description of proton scattering on Ne18

    NASA Astrophysics Data System (ADS)

    Jaganathen, Y.; Michel, N.; Płoszajczak, M.

    2014-03-01

    Background: The structure of weakly bound/unbound nuclei close to particle drip lines is different from that around the valley of beta stability. A comprehensive description of these systems goes beyond the standard shell model (SM) and demands an open quantum system description of the nuclear many-body system. Purpose: For that purpose, we are using the Gamow shell model (GSM), which provides a fully microscopic description of bound and unbound nuclear states, nuclear decays, and reactions. We formulate the GSM in coupled-channel (GSM-CC) representation to describe low-energy elastic and inelastic scattering of protons on Ne18. Method: The GSM-CC formalism is applied to a translationally invariant Hamiltonian with an effective finite-range two-body interaction. We discuss in detail the GSM-CC formalism in coordinate space and give the description of the novel equivalent potential method for solving the GSM-CC system of integrodifferential equations. This method is then applied for the description of (p,p') reaction cross-sections. The reactions channels are built by GSM wave functions for the ground state 0+ and the first excited 2+ of Ne18 and a proton wave function expanded in different partial waves. The completeness of this basis is verified by comparing GSM and GSM-CC energies of low-energy resonant states in Na19. The differences between the two calculations provide a measure of the missing configurations in the GSM-CC calculation of low-energy states of Na19 due to the restriction on the number of excited states of Ne18. Results: We present the first application of the GSM-CC formalism for the calculation of excited states of Ne18 and Na19, the excitation function, and the elastic/inelastic differential cross-sections in the Ne18(p,p') reaction at different energies. This is the first unified description of the spectra and reaction cross-sections in the GSM formalism. The method is shown to be both feasible and accurate. The approximate equivalence of GSM

  17. Deeply Virtual Compton Scattering on the Proton

    NASA Astrophysics Data System (ADS)

    Hirlinger Saylor, Nicholas; JLab, CLAS Collaboration

    2013-10-01

    DVCS on the proton was measured at Jefferson Lab with CLAS at Hall B with a polarized 5.88 GeV electron beam on an unpolarized hydrogen target. A preliminary measurement of unpolarized and polarized cross sections was made over wide kinematics, from 1GeV2

  18. Elastic scattering polarimeter for a polarized antiproton beam at U-70 accelerator of IHEP

    NASA Astrophysics Data System (ADS)

    Bogdanov, A. A.; Chetvertkov, M. A.; Chetvertkova, V. A.; Garkusha, V. I.; Meschanin, A. P.; Mochalov, V. V.; Nurusheva, M. B.; Nurushev, S. B.; Ridiger, A. V.; Rykov, V. L.; Semenov, P. A.; Strikhanov, M. N.; Vasiliev, A. N.; Zapolsky, V. N.

    2016-02-01

    The absolute polarimeter based on the elastic p¯p-scattering in the diffraction kinematic regions with the total momentum transfer squared coverage of 0.1 < - t < 0.3 (GeV/c)2 is proposed for the polarized antiproton beam at the U-70 proton synchrotron of IHEP. It is shown that it would take ˜200-400 hours for measuring the beam polarization at the statistical errors of ΔPB/PB ≃10-15%. These time estimates include also the time which is necessary for the measurements of an analyzing power AN, using a polarized target. Besides the measurements of beam polarizations, the proposed polarimeter provides an opportunity for carrying out the experimental studies of the small momentum transfers physics which would be a valuable enrichment of the SPASCHARM experiment capabilities and its physics program.

  19. 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.

  20. 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.

  1. Prospects for measuring coherent neutrino-nucleus elastic scattering at a stopped-pion neutrino source

    SciTech Connect

    Scholberg, Kate

    2006-02-01

    Rates of coherent neutrino-nucleus elastic scattering at a high-intensity stopped-pion neutrino source in various detector materials (relevant for novel low-threshold detectors) are calculated. Sensitivity of a coherent neutrino-nucleus elastic scattering experiment to new physics is also explored.

  2. Resonant scattering of central plasma sheet protons by multiband EMIC waves and resultant proton loss timescales

    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

  3. Proton radiography, nuclear cross sections and multiple Coulomb scattering

    SciTech Connect

    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.

  4. Proton dose calculation on scatter-corrected CBCT image: Feasibility study for adaptive proton therapy

    PubMed Central

    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

  5. Proton scattering by a hydrogen atom in an effectively two-body model

    SciTech Connect

    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.

  6. Determination of the Proton's Weak Charge via Parity Violating Electron Scattering

    SciTech Connect

    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 Q2=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 Q2 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.

  7. Long-range azimuthal correlations in proton–proton and proton–nucleus collisions from the incoherent scattering of partons

    SciTech Connect

    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.

  8. Detecting skin malignancy using elastic light scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Canpolat, Murat; Akman, Ayşe; Çiftçioğlu, M. Akif; Alpsoy, Erkan

    2007-07-01

    We have used elastic light scattering spectroscopy to differentiate between malign and benign skin lesions. The system consists of a UV spectrometer, a single optical fiber probe and a laptop. The single optical fiber probe was used for both delivery and detection of white light to tissue and from the tissue. The single optical fiber probe received singly scattered photons rather than diffused photons in tissue. Therefore, the spectra are correlated with morphological differences of the cells. It has been shown that spectra of malign skin lesions are different than spectra of benign skin lesions. While slopes of the spectra taken on benign lesions or normal skin tissues were positive, slopes of the spectra taken on malign skin lesions tissues were negative. In vivo experiments were conducted on 20 lesions from 18 patients (11 men with mean age of 68 +/- 9 years and 7 women with mean age of 52 +/- 20 years) applied to the Department of Dermatology and Venerology. Before the biopsy, spectra were taken on the lesion and adjacent (approximately 1 cm distant) normal-appearing skin. Spectra of the normal skin were used as a control group. The spectra were correlated to the pathology results with sensitivity and specificity of 82% and 89%, respectively. Due to small diameter of fiber probe and limited number of sampling (15), some positive cases are missed, which is lowered the sensitivity of the system. The results are promising and could suggest that the system may be able to detect malignant skin lesion non-invasively and in real time.

  9. Elastic and quasielastic /sup 3/Hep-scattering at a /sup 3/He-momentum 2. 5 GeV/c

    SciTech Connect

    Blinov, A.V.; Vanyushin, I.A.; Grechko, V.E.; Drobot, V.V.; Ergakov, V.A.; Zombkovskii, S.M.; Kondratyuk, L.A.; Korolev, Y.V.; Selektor, Y.M.; Solov'ev, V.V.

    1985-07-01

    The differential cross sections for /sup 3/Hep elastic and quasielastic scattering and the mean energy loss of fast protons in the reaction p+/sup 3/He..-->..p/sub F/+X are obtained using the ITEP 80-cm liquid hydrogen bubble chamber, exposed to a /sup 3/He beam at momentum 2.5 GeV/c (the primary-proton kinetic energy in the rest frame of the nucleus is T/sub p/ = 0.318 GeV). The data are compared with the Glauber-Sitenko multiple-scattering-theory predictions.

  10. 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.

  11. Electrical Conduction in Pure Water - Trapping and Scattering of Positive Protons and Negative Proton Holes

    NASA Astrophysics Data System (ADS)

    Jie, Binbin; Sah, Chihtang

    2015-03-01

    Water has been characterized by hydronium (H3O)1+ and hydroxide (HO)1- ions, which fail to explain the electrical conductivity of even pure water. Experimental formulas of pure water versus temperature (0-100C) have employed 39 empirical parameters to fit 3 measured properties: ion concentration, and electrical conductance of pure water and (H3O)1+ ion. We have shown (4 invited talks, 3 articles in 14 months) that electrical conduction in pure water can be represented by 5 quasi-particles in the many-body water lattice: the mobile positively charged protons p+ and negatively charged proton holes p-, and the 3 charge states of the immobile water molecule as amphoteric protonic trap, V+ = (H3O)1+, V0+/- = (H2O)0+/-, and V- = (HO)1-; and as few as 6 physics parameters: 3 binding energies, 1 protonic density of state, and 2 Coulombic scattering strengths. Protons in water are strongly coupled to the protonic-phonons, oxygen-phonons and protonic-local modes. Impuritons and affinitons may be present in the hexagonal tunnels of the water lattices.

  12. High-Accuracy Analysis of Compton Scattering in Chiral EFT: Proton and Neutron Polarisabilities

    NASA Astrophysics Data System (ADS)

    Griesshammer, Harald W.; Phillips, Daniel R.; McGovern, Judith A.

    2013-10-01

    Compton scattering from protons and neutrons provides important insight into the structure of the nucleon. A new extraction of the static electric and magnetic dipole polarisabilities αE 1 and βM 1 of the proton and neutron from all published elastic data below 300 MeV in Chiral Effective Field Theory shows that within the statistics-dominated errors, the proton and neutron polarisabilities are identical, i.e. no iso-spin breaking effects of the pion cloud are seen. Particular attention is paid to the precision and accuracy of each data set, and to an estimate of residual theoretical uncertainties. ChiEFT is ideal for that purpose since it provides a model-independent estimate of higher-order corrections and encodes the correct low-energy dynamics of QCD, including, for few-nucleon systems used to extract neutron polarisabilities, consistent nuclear currents, rescattering effects and wave functions. It therefore automatically respects the low-energy theorems for photon-nucleus scattering. The Δ (1232) as active degree of freedom is essential to realise the full power of the world's Compton data.Its parameters are constrained in the resonance region. A brief outlook is provided on what kind of future experiments can improve the database. Supported in part by UK STFC, DOE, NSF, and the Sino-German CRC 110.

  13. Microscopic study of neutron elastic scattering from {sup 12}C, {sup 40}Ca, and {sup 208}Pb at intermediate energies

    SciTech Connect

    Alvi, M. A.; Arafah, M. R.; Madani, J. H.; Ahmad, I.

    2009-02-15

    Recent neutron elastic scattering differential cross section data for {sup 12}C, {sup 40}Ca, and {sup 208}Pb at several energies from 65 to 225 MeV have been analyzed using Glauber multiple scattering model, suitably modified to enlarge angular range of validity. The center of mass and Pauli pair correlations have been considered. The effect of the phase variation of the NN scattering amplitude on the calculated cross sections has been studied. A medium modification of the 'elementary' NN interaction is also considered. The neutron differential cross sections have been calculated using the phenomenological and the recently proposed semiphenomenological neutron and proton target densities so as to check the validity of the semiphenomenological density model. We found that our method of analysis gives a very good description of the experimental data.

  14. 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.

  15. Effect of Coulomb breakup on the elastic cross section of the 8B proton-halo projectile on a heavy, 208Pb target

    NASA Astrophysics Data System (ADS)

    Rangel, J.; Lubian, J.; Canto, L. F.; Gomes, P. R. S.

    2016-05-01

    We investigate the role of the breakup channel in the elastic and breakup cross sections, in collisions of proton-halo nuclei. For this purpose, we perform continuum discretized couple channel (CDCC) calculations for the 8B+208Pb system and evaluate polarization potentials. One-channel calculations including the polarization potential are shown to reproduce very well the elastic cross sections obtained by CDCC calculations. We also study the individual contributions of the Coulomb and the nuclear couplings to the cross sections. To complement our study, we compare the effects of the breakup channel in proton-halo and neutron-halo nuclei, performing calculations treating 8B as a 7B+n core-nucleon system, with an artificially low breakup threshold. When only the nuclear breakup is considered, this approach can reasonably describe the elastic scattering.

  16. Covariance Matrix of a Double-Differential Doppler-broadened Elastic Scattering Cross Section

    SciTech Connect

    Arbanas, Goran; Becker, B.; Dagan, R; Dunn, Michael E; Larson, Nancy M; Leal, Luiz C; Williams, Mark L

    2012-01-01

    Legendre moments of a double-differential Doppler-broadened elastic neutron scattering cross section on {sup 238}U are computed near the 6.67 eV resonance at temperature T = 10{sup 3} K up to angular order 14. A covariance matrix of these Legendre moments is computed as a functional of the covariance matrix of the elastic scattering cross section. A variance of double-differential Doppler-broadened elastic scattering cross section is computed from the covariance of Legendre moments.

  17. A resonant scattering formalism for a fluid loaded elastic spherical near a planar boundary

    NASA Astrophysics Data System (ADS)

    Bishop, Garner

    2002-11-01

    Free field scattering from stationary fluid loaded elastic targets is well known and understood in terms of free field resonant scattering theory (RST), that it is given by the superposition of resonant and background components, and that the resonant components can be isolated by subtraction of an appropriate background. Backgrounds for isolating free field resonance spectra are well known. However, RST for scattering from a fluid loaded elastic target near a planar boundary where target scattering is accompanied by target-boundary scattering is less well known. A T-matrix formalism for plane wave scattering from rigid and soft spheres near a planar penetrable boundary is generalized to include a fluid loaded elastic spherical shell and RST is used to replace the free field T-matrix for the elastic shell that occurs within the formalism. It is shown that target-boundary scattering couples resonant and background components, couples modal resonances, and produces super-resonances. A background is introduced and it is shown that while background scattering is suppressed, coupled background and resonant scattering is not. Numerical results demonstrate some of the effects of target boundary scattering on the free field resonant spectrum of the shell as well as the dependence of target-boundary scattering on target.

  18. Study of 180 Mev Proton Inelastic Scattering from SILICON-28 and SILICON-30.

    NASA Astrophysics Data System (ADS)

    Chen, Quan

    This thesis reports the measurement of cross section and analyzing power angular distribution of elastic and inelastic scattering of 180 MeV proton for ^ {28}Si and ^{30} Si. Measurements were carried out using the proton beam available at the Indiana University Cyclotron Facility. The scattered protons were detected using the QDDM magnetic spectrometer. The DWIA framework, in which most inelastic proton scattering observables are analyzed, has three ingredients, (1) NN-effective interaction, (2) transition density, and (3) distorted waves. The procedure used here to obtain effective NN-interaction empirically is that first suggested by J. J. Kelly. It models effective NN-interaction guided by the nuclear matter theory(G-matrix) and employs the local density approximation(LDA). By using the transitions, for which transition densities are known, it fits the inelastic observable to determine the parameters used to model the momentum transfer(q) and density(k_{F }) dependence of the effective interaction (here reference to as empirical interaction). The distorted waves are calculated in a self-consistent manner from the model empirical interaction. The salient results are: (1) It is observed that, although the data base was increased by combining the ^{16}O observable with those of ^{28}Si, it still was not large enough to determine all the parameters without ambiguity in terms of which the effective NN-interaction was modeled. (2) The model prediction of cross section and analyzing power in terms of DWIA, using both the Paris -g and empirical interaction, with the observed are compared. It is clear that the results and the technique used to obtain effective NN-interaction shows that there is substantial potential to gain both qualitative and quantitative insight into how the interaction between two nucleons is modified within the nuclear medium. In particular, at low-q effective interaction is reduced and at high-q repulsion is enhanced compared to free interaction

  19. Elastic Waves Scattering without Conversion in Metamaterials with Simultaneous Zero Indices for Longitudinal and Transverse Waves.

    PubMed

    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

  20. Proton dynamics in bacterial spores, a neutron scattering investigation

    NASA Astrophysics Data System (ADS)

    Colas de la Noue, Alexandre; Peters, Judith; Gervais, Patrick; Martinez, Nicolas; Perrier-Cornet, Jean-Marie; Natali, Francesca

    2015-01-01

    Results from first neutron scattering experiments on bacterial spores are reported. The elastic intensities and mean square displacements have a non-linear behaviour as function of temperature, which is in agreement with a model presenting more pronounced variations at around 330 K (57 ∘C) and 400 K (127 ∘C). Based on the available literature on thermal properties of bacterial spores, mainly referring to differential scanning calorimetry, they are suggested to be associated to main endothermic transitions induced by coat and/or core bacterial response to heat treatment.

  1. Measurement of proton-proton inelastic scattering cross-section at \\chem{\\sqrt {s} = 7\\,{ {TeV}}}

    NASA Astrophysics Data System (ADS)

    The TOTEM Collaboration; Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bossini, E.; Bozzo, M.; Brogi, P.; Brücken, E.; Buzzo, A.; Cafagna, F. S.; Calicchio, M.; Catanesi, M. G.; Covault, C.; Csanád, M.; Csörgő, T.; Deile, M.; Doubek, M.; Eggert, K.; Eremin, V.; Ferretti, R.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Intonti, R. A.; Kašpar, J.; Kopal, J.; Kundrát, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lokajíček, M.; Lo Vetere, M.; Rodríguez, F. Lucas; Macrí, M.; Mäki, T.; Mercadante, A.; Minafra, N.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Palazzi, P.; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Santroni, A.; Scribano, A.; Smajek, J.; Snoeys, W.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Vítek, M.; Welti, J.; Whitmore, J.; Wyszkowski, P.

    2013-01-01

    The TOTEM experiment at the LHC has measured the inelastic proton-proton cross-section at \\sqrt {s}= 7\\,{ { TeV}} in a β* = 90 m run with low inelastic pile-up. The measurement was based on events with at least one charged particle in the T2 telescope acceptance of 5.3 < |η| < 6.5 in pseudorapidity. Combined with data from the T1 telescope, covering 3.1 < |η| < 4.7, the cross-section for inelastic events with at least one |η| ⩽ 6.5 final-state particle was determined to be (70.5 ± 2.9) mb. This cross-section includes all central diffractive events of which maximally 0.25 mb is estimated to escape the detection of the telescopes. Based on models for low mass diffraction, the total inelastic cross-section was deduced to be (73.7 ± 3.4) mb. An upper limit of 6.31 mb at 95% confidence level on the cross-section for events with diffractive masses below 3.4 GeV was obtained from the difference between the overall inelastic cross-section obtained by TOTEM using elastic scattering and the cross-section for inelastic events with at least one |η| ⩽ 6.5 final-state particle.

  2. On the scattering behaviour of elastic waves in textile reinforced concrete

    NASA Astrophysics Data System (ADS)

    Weber, W.; Zastrau, B. W.

    2010-06-01

    An exact analytical solution for the scattering of antiplane elastic waves by a layered elastic eccentric inclusion is derived beginning from the solution of the wave equation in elliptic coordinates. The solution and its degenerate cases are compared with other models, e.g. the scattering due to concentric circular scatterers. The effects of the geometrical properties of the interphase are studied. Hereby the focus lies on geometric parameters which fit the needs of Textile Reinforced Concrete (TRC). The calculations are performed for material properties as they occur with TRC. The numerical results show an enormous influence of eccentricities within TRC to its wave scattering behaviour.

  3. Cancer detection using NIR elastic light scattering and tissue fluorescence imaging

    SciTech Connect

    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.

  4. Parton-parton elastic scattering and rapidity gaps at SSC and LHC energies

    SciTech Connect

    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.

  5. Parton-parton elastic scattering and rapidity gaps at Tevatron energies

    SciTech Connect

    Del Duca, V.; Tang, Wai-Keung

    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 Tevatron energies.

  6. Measurements of electron-proton elastic cross sections for 0.4 < Q{sup 2} < 5.5 (GeV/c){sup 2}

    SciTech Connect

    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.

  7. Elastic properties of a polyimide film determined by Brillouin scattering and mechanical techniques

    SciTech Connect

    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.

  8. Analysis of elastic {alpha}-nucleus scattering data at 240 MeV

    SciTech Connect

    Alvi, M. A.; Madani, J. H.; Hakmi, A. M.

    2007-06-15

    Working within the framework of the Coulomb modified Glauber model we fit the elastic differential scattering cross section of 240 MeV {alpha} particle on {sup 58}Ni using the effective N-{alpha} amplitude with one adjustable parameter. It is found that once the effective amplitude is calibrated on {sup 58}Ni by varying the adjustable parameter, it very nicely reproduces the available elastic {alpha} scattering data on other nuclei at the same energy.

  9. Relative Angle-Differential Cross Sections for Elastic Electron Scattering from Pyrimidine

    NASA Astrophysics Data System (ADS)

    Maljkovic, J. B.; Milosavljevic, A. R.; Sevic, D.; Marinkovic, B. P.

    2008-07-01

    Angle-differential cross sections for elastic scattering of electrons from pyrimidine are reported for the incident energies from 50-300 eV. Measurements were performed using a cross-beam technique, for scattering angles from 20^o to 110^o. Experimental relative elastic differential cross sections are compared with recent theoretical results for uracil, which is a pyrimidine base and a component of ribonucleic acid.

  10. 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.

  11. Theoretical modeling for neutron elastic scattering angular distribution in the fast energy range

    SciTech Connect

    Kawano, Toshihiko

    2010-12-07

    One of the major issues of neutron scattering modeling in the fast energy range is the contribution of compound elastic and inelastic scattering to the total scattering process. The compound component may become large at very low energies where the angular distribution becomes 90-degree symmetric in the center-of-mass system. Together with the shape elastic component, the elastic scattering gives slightly forward-peaked angular distributions in the fast energy range. This anisotropic angular distribution gives high sensitivities to many important nuclear reactor characteristics, such as criticality and neutron shielding. In this talk we describe how the anisotropic angular distributions are calculated within the statistical model framework, including the case where strongly coupled channels exist, by combining the coupled-channels theory with the Hauser-Feshbach model. This unique capability extension will have significant advantages in understanding the neutron scattering process for deformed nuclei, like uranium or plutonium, on which advanced nuclear energy applications center.

  12. 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).

  13. Proton Spin Polarizabilities with Polarized Compton Scattering at MAMI

    NASA Astrophysics Data System (ADS)

    Paudyal, Dilli; A2 Collaboration

    2015-10-01

    The nucleon polarizabilities are fundamental structure observables, which describe its response to an applied electric or magnetic field. While the electric and magnetic scalar polarizabilities of the nucleon have been measured, little effort has been made to extract the spin dependent polarizabilities. These leading order spin dependent terms of the nucleon polarizabilities, γE1E1 ,γM1M1 ,γM1E2 and γE1M2 describe the spin response of a proton to electric and magnetic dipole and quadrupole interactions. We plan to extract these spin polarizabilities of the proton using real polarised Compton scattering off the proton at the MAMI tagged photon facility in Mainz, Germany. This requires precise measurement of the single and double polarization observables which are sensitive to these polarizabilities. The double polarization observables ∑2 x, ∑2 z are measured via a circulary polarized photon beam and a transversely and a linearly polarized butanol target in the resonance region (E = 250 - 310 MeV). This presentation will be focused on the status and analyis of an experiment completed at MAMI in 2014 and 2015 for the measurement of ∑2 z at different energies and angles. Supported by the Natural Sciences and Engineering Research Council of Canada (NSERC).

  14. Extraction of the proton radius from electron-proton scattering data

    NASA Astrophysics Data System (ADS)

    Lee, Gabriel; Arrington, John R.; Hill, Richard J.

    2015-07-01

    We perform a new analysis of electron-proton scattering data to determine the proton electric and magnetic radii, enforcing model-independent constraints from form factor analyticity. A wide-ranging study of possible systematic effects is performed. An improved analysis is developed that rebins data taken at identical kinematic settings and avoids a scaling assumption of systematic errors with statistical errors. Employing standard models for radiative corrections, our improved analysis of the 2010 Mainz A1 Collaboration data yields a proton electric radius rE=0.895 (20 ) fm and magnetic radius rM=0.776 (38 ) fm . A similar analysis applied to world data (excluding Mainz data) implies rE=0.916 (24 ) fm and rM=0.914 (35 ) fm . The Mainz and world values of the charge radius are consistent, and a simple combination yields a value rE=0.904 (15 ) fm that is 4 σ larger than the CREMA Collaboration muonic hydrogen determination. The Mainz and world values of the magnetic radius differ by 2.7 σ , and a simple average yields rM=0.851 (26 ) fm . The circumstances under which published muonic hydrogen and electron scattering data could be reconciled are discussed, including a possible deficiency in the standard radiative correction model which requires further analysis.

  15. Differential elastic scattering cross sections for 54.9eV positrons incident on helium

    NASA Technical Reports Server (NTRS)

    Chaplin, R. L.; Diana, L. M.; Brooks, D. L.

    1990-01-01

    Absolute differential elastic scattering cross sections measured with the 3-m, high resolution, time-of-flight spectrometer are presented for 54.9eV positrons incident on He. Five point moving average differential cross sections are plotted against average scattering angles which range from 14 to 36 deg. Also the averages of five differential cross sections which have adjacent values of scattering angle are plotted versus the corresponding averages of the scattering angles. The curve fitted to these data is shaped like the theoretical curve but has its minimum and its maximum at scattering angles that are about 4 deg higher and 15 deg lower respectively than predicted by theory.

  16. Diffusive properties of water in Artemia cysts as determined from quasi-elastic neutron scattering spectra.

    PubMed Central

    Trantham, E C; Rorschach, H E; Clegg, J S; Hazlewood, C F; Nicklow, R M; Wakabayashi, N

    1984-01-01

    Results have been obtained on the quasi-elastic spectra of neutrons scattered from pure water, a 20% agarose gel (hydration four grams H2O per gram of dry solid) and cysts of the brine shrimp Artemia for hydrations between 0.10 and 1.2 grams H2O 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 (Q2) 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 [u2] as determined from the Q-dependence of the line areas were also obtained. PMID:6733243

  17. Elastic, charge transfer, and related transport cross sections for proton impact of atomic hydrogen for astrophysical and laboratory plasma modeling

    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.

  18. Anisotropic Elastic Resonance Scattering model for the Neutron Transport equation

    SciTech Connect

    Mohamed Ouisloumen; Abderrafi M. Ougouag; Shadi Z. Ghrayeb

    2014-11-24

    The resonance scattering transfer cross-section has been reformulated to account for anisotropic scattering in the center-of-mass of the neutron-nucleus system. The main innovation over previous implementations is the relaxation of the ubiquitous assumption of isotropic scattering in the center-of-mass and the actual effective use of scattering angle distributions from evaluated nuclear data files in the computation of the angular moments of the resonant scattering kernels. The formulas for the high order anisotropic moments in the laboratory system are also derived. A multi-group numerical formulation is derived and implemented into a module incorporated within the NJOY nuclear data processing code. An ultra-fine energy mesh cross section library was generated using these new theoretical models and then was used for fuel assembly calculations with the PARAGON lattice physics code. The results obtained indicate a strong effect of this new model on reactivity, multi-group fluxes and isotopic inventory during depletion.

  19. 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}.

  20. Measurements of Compton Scattering on the Proton at 2 - 6 GeV

    SciTech Connect

    Danagoulian, Areg

    2006-05-01

    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 θcm = 120o. 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.

  1. Leakage and scatter radiation from a double scattering based proton beamline.

    PubMed

    Moyers, M F; Benton, E R; Ghebremedhin, A; Coutrakon, G

    2008-01-01

    Proton beams offer several advantages over conventional radiation techniques for treating cancer and other diseases. These advantages might be negated if the leakage and scatter radiation from the beamline and patient are too large. Although the leakage and scatter radiation for the double scattering proton beamlines at the Loma Linda University Proton Treatment Facility were measured during the acceptance testing that occurred in the early 1990s, recent discussions in the radiotherapy community have prompted a reinvestigation of this contribution to the dose equivalent a patient receives. The dose and dose equivalent delivered to a large phantom patient outside a primary proton field were determined using five methods: simulations using Monte Carlo calculations, measurements with silver halide film, measurements with ionization chambers, measurements with rem meters, and measurements with CR-39 plastic nuclear track detectors. The Monte Carlo dose distribution was calculated in a coronal plane through the simulated patient that coincided with the central axis of the beam. Measurements with the ionization chambers, rem meters, and plastic nuclear track detectors were made at multiple locations within the same coronal plane. Measurements with the film were done in a plane perpendicular to the central axis of the beam and coincident with the surface of the phantom patient. In general, agreement between the five methods was good, but there were some differences. Measurements and simulations also tended to be in agreement with the original acceptance testing measurements and results from similar facilities published in the literature. Simulations illustrated that most of the neutrons entering the patient are produced in the final patient-specific aperture and precollimator just upstream of the aperture, not in the scattering system. These new results confirm that the dose equivalents received by patients outside the primary proton field from primary particles that leak

  2. Leakage and scatter radiation from a double scattering based proton beamline

    SciTech Connect

    Moyers, M. F.; Benton, E. R.; Ghebremedhin, A.; Coutrakon, G.

    2008-01-15

    Proton beams offer several advantages over conventional radiation techniques for treating cancer and other diseases. These advantages might be negated if the leakage and scatter radiation from the beamline and patient are too large. Although the leakage and scatter radiation for the double scattering proton beamlines at the Loma Linda University Proton Treatment Facility were measured during the acceptance testing that occurred in the early 1990s, recent discussions in the radiotherapy community have prompted a reinvestigation of this contribution to the dose equivalent a patient receives. The dose and dose equivalent delivered to a large phantom patient outside a primary proton field were determined using five methods: simulations using Monte Carlo calculations, measurements with silver halide film, measurements with ionization chambers, measurements with rem meters, and measurements with CR-39 plastic nuclear track detectors. The Monte Carlo dose distribution was calculated in a coronal plane through the simulated patient that coincided with the central axis of the beam. Measurements with the ionization chambers, rem meters, and plastic nuclear track detectors were made at multiple locations within the same coronal plane. Measurements with the film were done in a plane perpendicular to the central axis of the beam and coincident with the surface of the phantom patient. In general, agreement between the five methods was good, but there were some differences. Measurements and simulations also tended to be in agreement with the original acceptance testing measurements and results from similar facilities published in the literature. Simulations illustrated that most of the neutrons entering the patient are produced in the final patient-specific aperture and precollimator just upstream of the aperture, not in the scattering system. These new results confirm that the dose equivalents received by patients outside the primary proton field from primary particles that leak

  3. Comparison of exact and approximate evaluations of the single-scattering integral in nucleon-deuteron elastic scattering

    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.

  4. Real Compton Scattering on Proton at High Momentum Transfers

    SciTech Connect

    A. Danagoulian; D.J. Hamilton; C.E. Hyde-Wright; V.H. Mamyan; A.M. Nathan; M. Roedelbronn; B. Wojtsekhowski

    2005-06-01

    The E99-114 experiment was carried out to measure the cross sections for Real Compton Scattering (RCS) on the proton in the kinematic range s = 5-11 GeV{sup 2}, -t = 2-7 GeV{sup 2}. In addition, a measurement of longitudinal and transverse polarization transfers was made at s = 6.9 GeV{sup 2} and -t = 4.0 GeV{sup 2}. These measurements were done to test the existing theoretical mechanisms for this process and will possibly lead to the determination of RCS form factors which are related to the Generalized Parton Distributions (GPD). The experiment was conducted in Hall A of Thomas Jefferson National Accelerator Facility (Jefferson Lab). Final results of polarization transfer measurements are presented.

  5. The proton-deuteron scattering length in pionless EFT

    NASA Astrophysics Data System (ADS)

    König, Sebastian; Hammer, Hans-Werner

    2016-03-01

    We present a fully perturbative calculation of the quartet-channel proton-deuteron scattering length (4ap-d) up to next-to-next-to-leading order (NNLO) in pionless effective field theory. In particular, we use a framework that consistently extracts the Coulomb-modified effective range function for a screened Coulomb potential in momentum space. We find a natural convergence pattern as we go to higher orders in the EFT expansion. Our NNLO result of (10.9 ± 0.4) fm agrees with older experimental determinations but deviates from more recent calculations, which find values around 14 fm. To resolve this discrepancy, we discuss the scheme dependence of Coulomb subtractions in a three-body system.

  6. 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.

  7. Elastic Scattering and Total Cross-Section in p+p Reactions --As Measured by the LHC Experiment TOTEM at √{s} = 7 TeV--

    NASA Astrophysics Data System (ADS)

    Csörgő, T.; Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bossini, E.; Bozzo, M.; Brogi, P.; Brücken, E.; Buzzo, A.; Cafagna, F. S.; Calicchio, M.; Catanesi, M. G.; Covault, C.; Csanád, M.; Deile, M.; Dimovasili, E.; Doubek, M.; Eggert, K.; Eremin, V.; Ferretti, R.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Intonti, M. R.; Janda, M.; Kašpar, J.; Kopal, J.; Kundrát, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lokajíček, M.; Lo Vetere, M.; Lucas Rodríguez, F.; Macrí, M.; Magaletti, L.; Magazzù, G.; Mercadante, A.; Meucci, M.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Noschis, E.; Novák, T.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Palazzi, P.; Perrot, A.-L.; Pedreschi, E.; PetäJäjärvi, J.; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Sanguinetti, G.; Santroni, A.; Scribano, A.; Sette, G.; Snoeys, W.; Spinella, F.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Vítek, M.; Welti, J.; Whitmore, J.; Totem Collaboration

    Proton-proton elastic scattering has been measured by the TOTEMexperiment at the CERN Large Hadron Collider at √{s} = 7 TeV in special runs with the Roman Pot detectors placed as close to the outgoing beam as seven times the transverse beam size. The differential cross-section measurements are reported in the |t|-range of 0.36 to 2.5 GeV^{2}. Extending the range of data to low t values from 0.02 to 0.33 GeV^2, and utilizing the luminosity measurements of CMS, the total proton-proton cross section at √{s} = 7 TeV is measured to be (98.3 ± 0.2^{stat} ± 2.8^{syst}) mb.

  8. 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.

  9. 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.

  10. Complex Correlation Kohn-T Method of Calculating Total and Elastic Cross Sections. Part 1; Electron-Hydrogen Elastic Scattering

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.; Temkin, A.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We report on the first part of a study of electron-hydrogen scattering, using a method which allows for the ab initio calculation of total and elastic cross sections at higher energies. In its general form the method uses complex 'radial' correlation functions, in a (Kohn) T-matrix formalism. The titled method, abbreviated Complex Correlation Kohn T (CCKT) method, is reviewed, in the context of electron-hydrogen scattering, including the derivation of the equation for the (complex) scattering function, and the extraction of the scattering information from the latter. The calculation reported here is restricted to S-waves in the elastic region, where the correlation functions can be taken, without loss of generality, to be real. Phase shifts are calculated using Hylleraas-type correlation functions with up to 95 terms. Results are rigorous lower bounds; they are in general agreement with those of Schwartz, but they are more accurate and outside his error bounds at a couple of energies,

  11. Proton-Nucleus Scattering Approximations and Implications for LHC Crystal Collimation

    SciTech Connect

    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.

  12. Elastic scattering and total reaction cross section of {sup 6}He+{sup 120}Sn

    SciTech Connect

    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.

  13. Weak-neutral-current elastic scattering of neutrinos

    SciTech Connect

    Lanou, R.E.

    1982-01-01

    We present progress to date in an experiment (E0734) to measure neutral current phenomena at low neutrino energy (200 less than or equal to E/sub nu/ less than or equal to 3 GeV). The principal goals center upon the elastic reactions: anti nu/sub ..mu../ + p ..-->.. anti nu/sub ..mu../ + p, and anti nu/sub ..mu../ + e ..-->.. anti nu/sub ..mu../ + e.

  14. Generalized topological sensitivity for inverse scattering of elastic waves

    NASA Astrophysics Data System (ADS)

    Chikichev, Ivan Sergeevich

    The focus of this research is an extension of the concept of topological sensitivity, rooted in theories of shape optimization and elastostatics, to three-dimensional elastodynamics and its application toward preliminary reconstruction and characterization of inner defects by way of elastic waves. In particular the original concept, which exercises the idea of cavity nucleation, is generalized to permit germination of solid obstacles. The main result of the proposed generalization is an expression for topological sensitivity, explicit in terms of either the elastodynamic Green's function or the so-called adjoint solution, that is obtained by an asymptotic expansion of a misfit-type cost functional with respect to the nucleation of a dissimilar elastic inclusion in a defect-free "reference" solid. To cater for a variety of physical applications including shallow seismic exploration, material testing, and medical imaging, the proposed methodology is developed both in the frequency domain and the time domain. The featured formula, consisting of an inertial-contrast monopole term and an elasticity-contrast dipole term, is shown to be applicable to a variety of reference domains such as finite, semi-infinite, and infinite homogeneous solids as well as their heterogeneous counterparts with smoothly-varying elastic properties. Through numerical examples, it is shown that the generalized topological sensitivity can be used as a robust and computationally-effective obstacle indicator through an assembly of sampling points where it attains pronounced negative values. On varying the material characteristics of the nucleating obstacle, a new identification algorithm is developed that permits the use of the featured sensitivity as a preparatory tool for both geometric and material characterization of internal defects.

  15. Probing elastic and inelastic breakup contributions to intermediate-energy two-proton removal reactions

    NASA Astrophysics Data System (ADS)

    Wimmer, K.; Bazin, D.; Gade, A.; Tostevin, J. A.; Baugher, T.; Chajecki, Z.; Coupland, D.; Famiano, M. A.; Ghosh, T. K.; Grinyer, G. F.; Hodges, R.; Howard, M. E.; Kilburn, M.; Lynch, W. G.; Manning, B.; Meierbachtol, K.; Quarterman, P.; Ratkiewicz, A.; Sanetullaev, A.; Stroberg, S. R.; Tsang, M. B.; Weisshaar, D.; Winkelbauer, J.; Winkler, R.; Youngs, M.

    2012-05-01

    The two-proton removal reaction from 28Mg projectiles has been studied at 93 MeV/u. First coincidence measurements of the heavy 26Ne projectile residues, the removed protons, and other light charged particles enabled the relative cross sections from each of the three possible elastic and inelastic proton removal mechanisms to be determined. These more final-state-exclusive measurements are key for further interrogation of these reaction mechanisms and use of the reaction channel for quantitative spectroscopy of very neutron-rich nuclei. The relative and absolute yields of the three contributing mechanisms are compared to reaction model expectations based on the use of eikonal dynamics and sd-shell-model structure amplitudes.

  16. CDCC calculations of elastic scattering for the systems 6Li+144Sm and 6Li+208Pb. Effect of resonances of 6Li on elastic scattering angular distributions

    NASA Astrophysics Data System (ADS)

    Gómez Camacho, A.

    2015-01-01

    Calculations of elastic scattering angular distributions for reactions of the weakly bound projectile 6Li with targets 144Sm and 208Pb at energies above the barrier, are performed with the Continuum Discretized Coupled-Channel method (CDCC). Ground, resonant and nonresonant continuum states of 6Li are included up to some maximum energy epsilonmax for which convergence is achieved. In the three-body system, global interactions are used for the α-target and d - target sub-systems. The effect of continuum resonant states of 6Li, i.e., l = 2, jπ = 3+, 2+ and 1+ on elastic scattering angular distributions is investigated by extracting these states from the continuum space. It is found that the calculated elastic scattering angular distributions are in good agreement with the measurements for most of the cases studied where consideration of couplings to continuum states is essential. It is also found that the resonance character of the continuum states is in some cases important to obtain agreement with the data.

  17. Evolution of Elastic X-ray Scattering in Laser-Shocked Warm Dense Li

    SciTech Connect

    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.

  18. Structure of elastic p-p scattering at low and high energies

    NASA Astrophysics Data System (ADS)

    Arash, Firooz; Moravcsick, Michael J.; Goldstein, Gary R.

    1985-02-01

    It is observed that p-p elastic scattering at 90° between 0.3 and 1.0 GeV is described by planar-transverse amplitude of which two are equal in magnitude and one is about three times larger in magnitude. This feature, extrapolated to much higher energies, is used to predict p-p polarization quantities, in part by itself, in part in combination with the extension of another, previously observed feature of planar-transverse amplitudes. Comparison with existing data is favorable. Predictions are then made for other, yet unmeasured but readily measurable polarization quantities for p-p elastic scattering.

  19. Optical model potential for deuteron elastic scattering with 1 p -shell nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Pang, D. Y.; Lou, J. L.

    2016-07-01

    A set of global optical potential parameters, DA1p, for deuterons with the 1 p -shell nuclei is obtained by simultaneously fitting 67 sets of experimental data of deuteron elastic scattering from 6Li, 9Be, 10B, 11B, 12C, 13C, 14N, 16O, and 18O with incident energies between 5.25 and 170 MeV. DA1p improves the description of the deuteron elastic scattering from the 1 p -shell nuclei with respect to the existing systematic deuteron potentials and can give satisfactory reproduction of the experimental data with radiative nuclei such as 9Li, 10Be, 14C, and 14O.

  20. Elastic scattering and total reaction cross section for the 6He + 27Al system

    NASA Astrophysics Data System (ADS)

    Benjamim, E. A.; Lépine-Szily, A.; Mendes Junior, D. R.; Lichtenthäler, R.; Guimarães, V.; Gomes, P. R. S.; Chamon, L. C.; Hussein, M. S.; Moro, A. M.; Arazi, A.; Padron, I.; Alcantara Nuñez, J.; Assunção, M.; Barioni, A.; Camargo, O.; Denke, R. Z.; de Faria, P. N.; Pires, K. C. C.

    2007-03-01

    The elastic scattering of the radioactive halo nucleus 6He on 27Al target was measured at four energies close to the Coulomb barrier using the RIBRAS (Radioactive Ion Beams in Brazil) facility. The São Paulo Potential (SPP) was used and its diffuseness and imaginary strength were adjusted to fit the elastic scattering angular distributions. Reaction cross-sections were extracted from the optical model fits. The reduced reaction cross-sections of 6He on 27Al are similar to those for stable, weakly bound projectiles as 6,7Li, 9Be and larger than stable, tightly bound projectile as 16O on 27Al.

  1. Elastic epsilon/sup + -/-He scattering with the use of the model-potential method

    SciTech Connect

    Khan, P.; Datta, S.K.; Bhattacharyya, D.; Ghosh, A.S.

    1984-06-01

    A model-potential method has been used to evaluate the elastic e/sup + -/-He scattering at the low-incident energies. The potential contains one parameter to include the effect of short-range correlation. The results for the elastic e/sup + -/-He scattering have been obtained using the same parameter. Two model exchange potentials, one for s wave and the other for higher partial waves, have been employed. The present results are in good agreement with the measured values and refined theoretical predictions.

  2. 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.

  3. Possibility to measure elastic photon-photon scattering in vacuum

    SciTech Connect

    Eriksson, Daniel; Brodin, Gert; Stenflo, Lennart; Marklund, Mattias

    2004-07-01

    Photon-photon scattering in vacuum due to the interaction with virtual electron-positron pairs is a consequence of quantum electrodynamics. A way for detecting this phenomenon has been devised based on interacting modes generated in microwave wave guides or cavities [G. Brodin, M. Marklund, and L. Stenflo, Phys. Rev. Lett. 87, 171801 (2001)]. Here we materialize these ideas, suggest a concrete cavity geometry, make quantitative estimates and propose experimental details. It is found that detection of photon-photon scattering can be within the reach of present day technology.

  4. Absorption and elastic scattering of light by particle aggregates.

    PubMed

    Quinten, M; Kreibig, U

    1993-10-20

    Light scattering and absorption by spherical particles is extended to aggregates of spheres with arbitrary shape and size. We applied the theory of G6rardy and Ausloos [Phys. Rev. B 25, 4204-4229 (1082)] to compute the total extinction loss spectra of several aggregates of nanometer-sized silver spheres from the near IR to the near UV. Silver was best suited to provide quantitative comparison with experiments concerning the scattering and absorption in the visible spectral region. Additional resonant extinction was obtained besides the resonant extinction of the single silver sphere. The spectra were discussed in detail to give general results that are independent of the particle material. PMID:20856447

  5. 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.

  6. Halos and rainbows: The elastic scattering of light exotic nuclei

    SciTech Connect

    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.

  7. Optical diagnostics based on elastic scattering: An update of clinical demonstrations with the Optical Biopsy System

    SciTech Connect

    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.

  8. Systematics of nuclear charge distributions in the mass 60 region from elastic electron scattering and muonic x-ray measurements

    NASA Astrophysics Data System (ADS)

    Wohlfahrt, H. D.; Schwentker, O.; Fricke, G.; Andresen, H. G.; Shera, E. B.

    1980-07-01

    Precise ratios of elastic electron scattering cross sections for the nuclei 54,56,58Fe, 58,60,62,64Ni, and 64,66,68,70Zn have been measured in the momentum-transfer region 0.6 fm-1<=q<=2.3 fm-1. The data were analyzed with a Fourier-Bessel parametrization of the charge distribution. Charge distribution differences were determined nearly model independently for the ΔA=2 isotope and isotone pairs. The ΔZ=2 isotone charge distribution differences show a strong shell effect, if one compares the Ni-Fe charge distribution differences, where the two added protons close the 1f72 shell, and the Zn-Ni charge distribution differences, where the two added protons start to fill the 2p32 shell. For the ΔN=2 isotopes we observe a nearly constant increase of the "half density radius" in the investigated region of the 2p32, 1f52, and 2p12 neutron shells. However, the skin thickness of the charge distribution increases strongly at the beginning (56Fe-54Fe) and decreases at the end (70Zn-68Zn) of these shells by adding two neutrons. The rms radii differences deduced from a combined analysis of the electron scattering data and present muonic x-ray data show the same trend. These differences, determined model independently with a typical accuracy of some 10-3 fm, decrease nearly linearly with increasing neutron number in the investigated region 28<=N<=40. These isotope shifts are nearly independent of the proton configuration of the involved nuclei, which indicates that the added neutrons interact primarily with the proton core rather than with the valence protons. Recent calculations, which include ground state correlations, show that the observed isotope shifts reflect deformation changes caused by changes of the amplitude of the zero-point quadrupole surface oscillations. A comparison of the experimental charge distribution differences with results of density dependent Hartree-Fock calculations also indicates the importance of deformation changes. The core rearrangement due to

  9. Elastic and inelastic scattering of 15N ions by 9Be at 84 MeV

    NASA Astrophysics Data System (ADS)

    Rudchik, A. T.; Chercas, K. A.; Kemper, K. W.; Rusek, K.; Rudchik, A. A.; Herashchenko, O. V.; Koshchy, E. I.; Pirnak, Val. M.; Piasecki, E.; Trzcińska, A.; Sakuta, S. B.; Siudak, R.; Strojek, I.; Stolarz, A.; Ilyin, A. P.; Ponkratenko, O. A.; Stepanenko, Yu. M.; Shyrma, Yu. O.; Szczurek, A.; Uleshchenko, V. V.

    2016-03-01

    Angular distributions of the 9Be + 15N elastic and inelastic scattering were measured at Elab(15N) = 84 MeV (Ec.m. = 31.5 MeV) for the 0-6.76 MeV states of 9Be and 0-6.32 MeV states of 15N. The data were analyzed within the optical model and coupled-reaction-channels method. The elastic and inelastic scattering, spin reorientations of 9Be in ground and excited states and 15N in excited states as well as the most important one- and two-step transfer reactions were included in the channels-coupling scheme. The parameters of the 9Be + 15N optical potential of Woods-Saxon form as well as deformation parameters of these nuclei were deduced. The analysis showed that the 9Be + 15N pure potential elastic scattering dominates at the forward angles whereas the ground state spin reorientation of 9Be gives a major contribution to the elastic scattering cross sections at the large angles. Contributions from particle transfers are found to be negligible for the present scattering system.

  10. Elastic electron scattering in krypton in the energy range from 5 to 10 eV

    SciTech Connect

    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.

  11. Theory and laboratory experiments of elastic wave scattering by dry planar fractures

    NASA Astrophysics Data System (ADS)

    Blum, Thomas E.; Snieder, Roel; van Wijk, Kasper; Willis, Mark E.

    2011-08-01

    Remote sensing of fractures with elastic waves is important in fields ranging from seismology to nondestructive testing. In many geophysical applications, fractures control the flow of fluids such as water, hydrocarbons or magma. While previous analytic descriptions of scattering mostly deal with very large or very small fractures (compared to the dominant wavelength), we present an analytic solution for the scattering of elastic waves from a fracture of arbitrary size. Based on the linear slip model for a dry fracture, we derive the scattering amplitude in the frequency domain under the Born approximation for all combinations of incident and scattered wave modes. Our analytic results match laser-based ultrasonic laboratory measurements of a single fracture in clear plastic, allowing us to quantify the compliance of a fracture.

  12. sup 4 He- sup 4 He elastic scattering and variational wave functions

    SciTech Connect

    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.

  13. Sensitivity of cross sections for elastic nucleus-nucleus scattering to halo nucleus density distributions

    SciTech Connect

    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.

  14. Scaling analysis of bio-molecular dynamics derived from elastic incoherent neutron scattering experiments

    SciTech Connect

    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}.

  15. Scaling analysis of bio-molecular dynamics derived from elastic incoherent neutron scattering experiments

    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.

  16. Structure of neutron-rich Isotopes {sup 8}Li and {sup 9}Li and allowance for it in elastic scattering

    SciTech Connect

    Ibraeva, E. T.; Zhusupov, M. A.; Imambekov, O.; Sagindykov, Sh. Sh.

    2008-07-15

    The differential cross sections for elastic proton scattering on the unstable neutron-rich nuclei {sup 8}Li and {sup 9}Li at E = 700 and 60 MeV per nucleon were considered. The {sup 8}Li nucleus was treated on the basis of the three-body {alpha}-t-n model, while the {sup 9}Li nucleus was considered within the {alpha}-t-n and {sup 7}Li-n-n models. The cross sections in question were calculated within Glauber diffraction theory. A comparison of the results with available experimental data made it possible to draw conclusions on the quality of the wave functions and potential used in the calculations.

  17. Forward sum rule for the 2 γ -exchange correction to the charge-radius extraction from elastic electron scattering

    NASA Astrophysics Data System (ADS)

    Gorchtein, Mikhail

    2014-11-01

    Two-photon-exchange (TPE) contributions to elastic electron-proton scattering in the forward regime in leading logarithmic ˜t ln|t | approximation in the momentum transfer t are considered. The imaginary part of the TPE amplitude in the forward kinematics is related to the total photoabsorption cross section. The real part of the TPE amplitude is obtained from an unsubtracted fixed-t dispersion relation. This allows a clean prediction of the real part of the TPE amplitude at forward angles with the leading term ˜t ln|t | . Numerical estimates are comparable with or exceed the experimental precision in extracting the charge radius from the experimental data.

  18. 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.

  19. Neutron-proton effective mass splitting in neutron-rich matter at normal density from analyzing nucleon-nucleus scattering data within an isospin dependent optical model

    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.

  20. Measurement of muon neutrino quasi-elastic scattering on carbon

    SciTech Connect

    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.

  1. High precision elastic α scattering on the even-odd 115In nucleus at low energies

    NASA Astrophysics Data System (ADS)

    Kiss, G. G.; Szücs, T.; Mohr, P.; Fülöp, Zs; Gyürky, Gy; Halász, Z.; Soha, R. F.; Somorjai, E.; Ornelas, A.; Galaviz, D.; Yalçın, C.; Güray, R. T.; Özkan, N.

    2016-01-01

    Elastic alpha scattering cross sections on the even-odd 115In nucleus have been measured at energies Elab. = 16.15 MeV and 19.50 MeV. The high precision experimental data are used to derive the parameters of a local a nucleus optical potential.

  2. Impulsive Stimulated Light Scattering at High Pressure - Precise Determination of Elastic Constants of Opaque Materials

    SciTech Connect

    Crowhurst, J C; Zaug, J M; Abramson, E H; Brown, J M; Ahre, D W

    2002-08-22

    Impulsive stimulated light scattering has been used to measure interfacial wave propagation speeds and elastic constants under conditions of high pressure. Data obtained from single-crystal Ge and Fe, and from polycrystalline Ta is presented. The method is complementary to other techniques for obtaining this type of information. There appears no fundamental reason why it cannot be extended to the 1 Mbar regime.

  3. 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.

  4. Residual-stress characterization by use of elastic-wave-scattering measurements

    SciTech Connect

    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.

  5. Single-collision approximation for p{sup 3}-He elastic scattering at low energy

    SciTech Connect

    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.

  6. Elastic pp Scattering at LHC Energies in Various Multi-Pomeron Exchange Models

    NASA Astrophysics Data System (ADS)

    Novikov, Ivan; Shabelski, Yuli

    2012-10-01

    We consider the data for elastic pp scattering in the framework of Regge theory in various models of multiple Pomeron exchanges: quasi-eikonal approach and two-channel approach. The results of the model calculations are compared with the experimental data presented by the TOTEM collaboration.

  7. Elastic neutrino-electron scattering: a progress report on Exp734 at Brookhaven

    SciTech Connect

    Abe, K.; Ahrens, L.A.; Amako, K.

    1983-01-01

    I will report preliminary results on elastic neutrino-electron scattering from data taken with the 200 ton segmented liquid scintillator - proportional drift-tube neutrino detector at Brookhaven. Features of the detector (such as the active target and long radiation length) permit a uniquely clean signal. Prospects of results from the completed analysis and further data taking are discussed.

  8. Spin structure of the proton from polarized inclusive deep-inelastic muon-proton scattering

    SciTech Connect

    Spin Muon Collaboration

    1997-11-01

    We have measured the spin-dependent structure function g{sub 1}{sup p} in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range 0.003{lt}x{lt}0.7 and 1GeV{sup 2}{lt}Q{sup 2}{lt}60GeV{sup 2}. A next-to-leading order QCD analysis is used to evolve the measured g{sub 1}{sup p}(x,Q{sup 2}) to a fixed Q{sub 0}{sup 2}. The first moment of g{sub 1}{sup p} at Q{sub 0}{sup 2}=10GeV{sup 2} is {Gamma}{sub 1}{sup p}=0.136{plus_minus}0.013 (stat) {plus_minus}0.009 (syst) {plus_minus}0.005 (evol). This result is below the prediction of the Ellis-Jaffe sum rule by more than two standard deviations. The singlet axial charge a{sub 0} is found to be 0.28{plus_minus}0.16. In the Adler-Bardeen factorization scheme, {Delta}g{approx_equal}2 is required to bring {Delta}{Sigma} in agreement with the quark-parton model. A combined analysis of all available proton, deuteron, and {sup 3}He data confirms the Bjorken sum rule. {copyright} {ital 1997} {ital The American Physical Society}

  9. Elastic constants and dimensions of imprinted polymeric nanolines determined from Brillouin light scattering.

    PubMed

    Johnson, W L; Kim, S A; Geiss, R; Flannery, C M; Soles, C L; Wang, C; Stafford, C M; Wu, W-L; Torres, J M; Vogt, B D; Heyliger, P R

    2010-02-19

    Elastic constants and cross-sectional dimensions of imprinted nanolines of poly(methyl methacrylate) (PMMA) on silicon substrates are determined nondestructively from finite-element inversion analysis of dispersion curves of hypersonic acoustic modes of these nanolines measured with Brillouin light scattering. The results for the cross-sectional dimensions, under the simplifying assumption of vertical sides and a semicircular top, are found to be consistent with dimensions determined from critical-dimension small-angle x-ray scattering measurements. The elastic constants C(11) and C(44) are found to be, respectively, 11.6% and 3.1% lower than their corresponding values for bulk PMMA. This result is consistent with the dimensional dependence of the quasi-static Young's modulus determined from buckling measurements on PMMA films with lower molecular weights. This study provides the first evidence of size-dependent effects on hypersonic elastic properties of polymers. PMID:20081293

  10. SU-E-J-175: Proton Dose Calculation On Scatter-Corrected CBCT Image: Feasibility Study for Adaptive Proton Therapy

    SciTech Connect

    Park, Y; Winey, B; Sharp, G

    2014-06-01

    Purpose: To demonstrate feasibility of proton dose calculation on scattercorrected CBCT images for the purpose of adaptive proton therapy. Methods: Two CBCT image sets were acquired from a prostate cancer patient and a thorax phantom using an on-board imaging system of an Elekta infinity linear accelerator. 2-D scatter maps were estimated using a previously introduced CT-based technique, and were subtracted from each raw projection image. A CBCT image set was then reconstructed with an open source reconstruction toolkit (RTK). Conversion from the CBCT number to HU was performed by soft tissue-based shifting with reference to the plan CT. Passively scattered proton plans were simulated on the plan CT and corrected/uncorrected CBCT images using the XiO treatment planning system. For quantitative evaluation, water equivalent path length (WEPL) was compared in those treatment plans. Results: The scatter correction method significantly improved image quality and HU accuracy in the prostate case where large scatter artifacts were obvious. However, the correction technique showed limited effects on the thorax case that was associated with fewer scatter artifacts. Mean absolute WEPL errors from the plans with the uncorrected and corrected images were 1.3 mm and 5.1 mm in the thorax case and 13.5 mm and 3.1 mm in the prostate case. The prostate plan dose distribution of the corrected image demonstrated better agreement with the reference one than that of the uncorrected image. Conclusion: A priori CT-based CBCT scatter correction can reduce the proton dose calculation error when large scatter artifacts are involved. If scatter artifacts are low, an uncorrected CBCT image is also promising for proton dose calculation when it is calibrated with the soft-tissue based shifting.

  11. Quantum manifestations of chaos in elastic atom-surface scattering

    SciTech Connect

    Guantes, R.; Miret-Artes, S.; Borondo, F.

    2001-06-15

    Quantum manifestations of chaos in the diffraction of atoms from corrugated surfaces, for a range of initial conditions easily attainable in scattering experiments, are presented and discussed. The appearance of strong oscillations in diffraction patterns is shown to be directly related to the presence of classical chaos and threshold effects. We also show that the autocorrelation function for some of the collision S-matrix elements over incident angles is sensitive to the character, hyperbolic or nonhyperbolic, of the underlying chaotic dynamics, in agreement with general semiclassical arguments for unbound chaotic systems.

  12. Elastic Scattering of Low-Energy Electrons byTetrahydrofuran

    SciTech Connect

    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.

  13. Quasi-elastic light scattering from structured particles.

    PubMed

    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

  14. Low energy positron interactions with uracil—Total scattering, positronium formation, and differential elastic scattering cross sections

    SciTech Connect

    Anderson, E. K.; Boadle, R. A.; Machacek, J. R.; Makochekanwa, C.; Sullivan, J. P.; Chiari, L.; Buckman, S. J.; Brunger, M. J.; Garcia, G.; Blanco, F.; Ingolfsson, O.

    2014-07-21

    Measurements of the grand total and total positronium formation cross sections for positron scattering from uracil have been performed for energies between 1 and 180 eV, using a trap-based beam apparatus. Angular, quasi-elastic differential cross section measurements at 1, 3, 5, 10, and 20 eV are also presented and discussed. These measurements are compared to existing experimental results and theoretical calculations, including our own calculations using a variant of the independent atom approach.

  15. Elastic Scattering between Ultracold 23Na and 85Rb Atoms in the Triplet State

    NASA Astrophysics Data System (ADS)

    Hu, Qiu-Bo; Zhang, Yong-Sheng; Sun, Jin-Feng; Yu, Ke

    2011-04-01

    The elastic scattering properties between ultracold 23Na and 85Rb atoms for the triplet state (a3 Σ+u) are researched. The s-wave scattering lengths of 23Na and 85Rb are calculated by the Numerov and semiclassical method with two kinds of interatomic potentials, which are the interpolation potential and Lennard—Jones potential (LJ12,6) by the same phase Φ. Shape resonances appear clearly in the l = 5 partial waves for the a3 Σ+u state. Moreover, the s-wave scattering cross section, total cross section and energy positions of shape resonances are also discussed.

  16. Nanoscale structure in AgSbTe2 determined by diffuse elastic neutron scattering

    SciTech Connect

    Specht, Eliot D; Ma, Jie; Delaire, Olivier A; Budai, John D; May, Andrew F; Karapetrova, Evguenia A.

    2015-01-01

    Diffuse elastic neutron scattering measurements confirm that AgSbTe2 has a hierarchical structure, with defects on length scales from nanometers to microns. While scattering from mesoscale structure is consistent with previously-proposed structures in which Ag and Sb order on a NaCl lattice, more diffuse scattering from nanoscale structure suggests a structural rearrangement in which hexagonal layers form a combination of (ABC), (ABA), and (AAB) stacking sequences. The AgCrSe2 structure is the best-fitting model for the local atomic arrangements.

  17. 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.

  18. Counter-ions dynamics in highly plastic and conducting compounds of poly(aniline). A quasi-elastic neutron scattering study.

    PubMed

    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. PMID:19791338

  19. Optical diagnostics based on elastic scattering: Recent clinical demonstrations with the Los Alamos Optical Biopsy System

    SciTech Connect

    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.

  20. 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.

  1. 8Li+α resonant elastic scattering: a tool to study cluster states in 12B

    NASA Astrophysics Data System (ADS)

    Torresi, D.; Cosentino, L.; Descouveont, P.; Di Pietro, A.; Ducoin, C.; Figuera, P.; Fisichella, M.; Lattuada, M.; Maiolino, C.; Musumarra, A.; Papa, M.; Pellegriti, M. G.; Rovituso, M.; Santonocito, D.; Scalia, G.; Scuderi, V.; Strano, E.; Zadro, M.

    2014-12-01

    The 8Li+4He elastic scattering excitation function was measured by using the inverse kinematic thick target method. The 8Li beam was provided by the LNS radioactive facility EXCYT at an energy of 30 MeV and it was delivered into a large scattering chamber filled with 4He gas. The detection system was made by three silicon telescopes and one MCP. This last detector was used to measure the number of incident particles as well as the time of flight allowing for the discrimination between elastic and inelastic scattering. The setup and the experimental technique will be described in details and the results, as well as the comparison of the data with an R-matrix calculation, will be shown and discussed.

  2. Analysis of proton scattering of stable and exotic light nuclei using an energy-dependent microscopic optical potential

    NASA Astrophysics Data System (ADS)

    Maridi, H. M.; Farag, M. Y. H.; Esmael, E. H.

    2016-01-01

    The proton elastic scattering off the 9,10,11,12Be isotopes at a wide energy range from 3 to 200 MeV/nucleon is analyzed using the optical model with the partial-wave expansion method. The microscopic optical potential (OP) is taken within the single-folding model. The density- and isospin-dependent M3YParis nucleon-nucleon (NN) interaction is used for the real part and the NN-scattering amplitude of the highenergy approximation for the imaginary one. The cross-section data are reproduced well at energies up to 100 MeV/nucleon by use of the partial-wave expansion. For higher energies, the eikonal approximation is successfully used. The volume integrals of the OP parts have systematic energy dependencies and they can be parameterized as functions of energy. From these parametrization, an energy-dependent OP can be obtained.

  3. High Precision Measurement of the Proton Elastic Form Factor Ratio at Low Q2

    SciTech Connect

    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.

  4. Modelling of nonlinear wave scattering in a delaminated elastic bar

    PubMed Central

    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

  5. Correlations among angular wave component amplitudes in elastic multiple-scattering random media.

    PubMed

    Hoover, Brian G; Deslauriers, Louis; Grannell, Shawn M; Ahmed, Rizwan E; Dilworth, David S; Athey, Brian D; Leith, Emmett N

    2002-02-01

    The propagation of scalar waves through random media that provide multiple elastic scattering is considered by derivation of an expression for the angular correlation of the scattered wave amplitudes. Coherent wave transmission is shown to occur through a mechanism similar to that responsible for coherent backscattering. While the properties of the scattered wave are generally consistent with radiative-transfer theory for sufficiently small incident and scattering angles, coherent transmission provides corrections to radiative-transfer results at larger angles. The theoretical angular correlation curves are fit, by specifying the probability densities of two random variables that correspond to material parameters, to measured data of laser light scattering from various polymer microsphere suspensions. PMID:11863685

  6. Measurement of the n-p elastic scattering angular distribution at E{sub n}=14.9 MeV

    SciTech Connect

    Boukharouba, N.; Bateman, F. B.; Carlson, A. D.; Brient, C. E.; Grimes, S. M.; Massey, T. N.; Haight, R. C.; Carter, D. E.

    2010-07-15

    The relative differential cross section for the elastic scattering of neutrons by protons was measured at an incident neutron energy E{sub n}=14.9 MeV and for center-of-mass scattering angles ranging from about 60 deg. to 180 deg. Angular distribution values were obtained from the normalization of the integrated data to the n-p total elastic scattering cross section. Comparisons of the normalized data to the predictions of the Arndt et al. phase-shift analysis, those of the Nijmegen group, and with the ENDF/B-VII.0 evaluation are sensitive to the value of the total elastic scattering cross section used to normalize the data. The results of a fit to a first-order Legendre polynomial expansion are in good agreement in the backward scattering hemisphere with the predictions of the Arndt et al. phase-shift analysis, those of the Nijmegen group, and to a lesser extent, with the ENDF/B-VII.0 evaluation. A fit to a second-order expansion is in better agreement with the ENDF/B-VII.0 evaluation than with the other predictions, in particular when the total elastic scattering cross section given by Arndt et al. and the Nijmegen group is used to normalize the data. A Legendre polynomial fit to the existing n-p scattering data in the 14 MeV energy region, excluding the present measurement, showed that a best fit is obtained for a second-order expansion. Furthermore, the Kolmogorov-Smirnov test confirms the general agreement in the backward scattering hemisphere and shows that significant differences between the database and the predictions occur in the angular range between 60 deg. and 120 deg. and below 20 deg. Although there is good overall agreement in the backward scattering hemisphere, more precision small-angle scattering data and a better definition of the total elastic cross section are needed for an accurate determination of the shape and magnitude of the angular distribution.

  7. Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton

    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.

  8. Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton.

    PubMed

    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 θ_{cm}^{p}=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 generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude. PMID:26550716

  9. 12C+ 12C elastic scattering excitation functions and phase shift analysis

    NASA Astrophysics Data System (ADS)

    Ledoux, R. J.; Bechara, M. J.; Ordonez, C. E.; Al-Juwair, H. A.; Cosman, E. R.

    1983-03-01

    The 12C+ 12C elastic scattering has been measured for Ec.m.=14.6-31.3 MeV, θc.m.=30°-110°. The elastic data have been analyzed via a phase shift analysis, enabling the extraction of model independent sets of phase shift parameters. The extracted Jπ values for the intermediate structure resonances at Ec.m.=18.4, 19.3, and 20.3 MeV are 12+, 12+, and 12+ or 14+, respectively. The questions of ambiguities in the phase shift analysis and the comparison with Jπ values deduced from other experiments are discussed. Evidence is presented for the existence of gross structure resonances. The elastic scattering has also been analyzed using the sum-of-differences method to directly extract the total reaction cross section. The results of these analyses are compared to existing models of the origin of intermediate structure resonances. NUCLEAR REACTIONS Measured the 12C+ 12C elastic scattering, Ec.m.=14.6-31.3 MeV, θc.m.=30°-110°. Phase shift analysis, sum-of-differences analysis.

  10. Hyperdeformed band in 36Ar populated in the 12C + 24Mg elastic scattering

    NASA Astrophysics Data System (ADS)

    Lépine-Szily, A.; Sciani, W.; Benjamim, E. A.; Chamon, L. C.; Lichtenthäler, R.; Otani, Y.

    2008-05-01

    The strongly oscillating angular distributions of the elastic scattering of 12C + 24Mg at energies around the Coulomb barrier (Ecm = 10.67 - 16.00 MeV) [1] were reproduced adding three Breit-Wigner resonance terms with J values of 6, 7 and 8 h respectively to the l = 6, 7 and 8 terms of the elastic S-matrix. The elastic scattering S-matrix was calculated using the double folding, deep, optical potential with non-local interaction, also called, Sao Paulo Potential [2]. All fifteen angular distributions could be well reproduced by the 3 resonances, located respectively at Ecm = 14.15, 15.8 and 16.9 MeV in the entrance channel, which correspond to excitation energies of 30.45, 32.1 and 33.2 MeV in the 36Ar compound nucleus. The J = 6, 7 and 8 h resonances fit well into a rotational molecular band, together with the J = 18, 20, 22 and 24 h resonances observed in the 16O + 20Ne elastic scattering [3]. The band head is at 29.5 MeV excitation energy in the 36Ar compound nucleus and has a large moment of inertia indicating a large deformation. Calculations of Rae and Merchant [4] propose the existence of a hyperdeformed band in 36Ar with 12C + 24Mg and 16O + 20Ne cluster structure.

  11. Towards a Precision Measurement of Parity-Violating e-p Elastic Scattering at Low Momentum Transfer

    SciTech Connect

    Pan, Jie

    2012-01-01

    The goal of the Q-weak experiment is to make a measurement of the proton's weak charge QWp = 1 - 4 sin2W2(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.

  12. Optimized determination of elastic constants of crystals and their uncertainties from surface Brillouin scattering.

    PubMed

    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. PMID:26899728

  13. Gamma rays from cosmic-ray proton scattering in AGN jets: the intra-cluster gas vastly outshines dark matter

    NASA Astrophysics Data System (ADS)

    Profumo, Stefano; Ubaldi, Lorenzo; Gorchtein, Mikhail

    2013-04-01

    Active Galactic Nuclei (AGN) host powerful jets containing high-energy electrons and protons. The astrophysical environment where AGNs and their jets are found is characterized by large concentrations of both dark matter (DM) and intra-cluster medium (ICM) gas. As the high-energy jet particles transverse the DM and the ICM, elastic and inelastic scattering processes generically lead to the production of final-state photons. As first envisioned by Bloom and Wells (1998), and as more recently pointed out by us and others, the scattering of electrons off of DM could lead to a potentially detectable gamma-ray signal, with the parton-level contribution from protons offering dimmer perspectives. Recently, Chang et al. argued that taking into account photons from hadronization and showering, the actual photon flux is substantially increased. Here, we point out that the proton-jets have to be highly collimated, contrary to what predicted by simple blob-geometry jet-models sometimes employed in these studies, otherwise they would produce a very large flux of photons from inelaystic collisions with ICM nucleons, which would outshine by many orders of magnitude the signal from DM, for almost any reasonable ICM and DM density profiles.

  14. 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

  15. Simplified treatment of exact resonance elastic scattering model in deterministic slowing down equation

    SciTech Connect

    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)

  16. Coupling between positronium formation and elastic positron-scattering channels in the rare gases

    SciTech Connect

    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.

  17. Proton scattering on carbon nuclei in bichromatic laser field at moderate energies

    NASA Astrophysics Data System (ADS)

    Barna, I. F.; Varró, S.

    2016-02-01

    We present the general theory for proton nuclei scattering in a bichromatic laser field. As a physical example we consider proton collision on 12C at 49 MeV/amu moderate energies in the field of a titan sapphire laser with its second harmonic.

  18. Analysis of approximations used in calculations of radiative corrections to electron-proton scattering cross section

    SciTech Connect

    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.

  19. Internal spin structure of the proton from high energy polarized e-p scattering

    SciTech Connect

    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.

  20. On the dyadic scattering problem in three-dimensional gradient elasticity: an analytic approach

    NASA Astrophysics Data System (ADS)

    Charalambopoulos, Antonios; Gergidis, Leonidas N.

    2008-10-01

    The investigation of the direct scattering problem of an elastic dyadic incident field from a spherical inclusion, is the main outcome of this work, in the case where the scatterer and the host environment dispose microstructure. The framework of the method is based on the implication of Mindlin's gradient theory. The development of the method is fully analytic and gives successively several byproducts, which are indispensable for the solution of the scattering problem but constitute also independent results of their own theoretical and practical value. So the numerable set of Navier eigendyadics is constructed, which is proved to be a basis for every dyadic field obeying the dynamic gradient elasticity equation. This permits the construction of a useful spectral representation for every gradient elasticity field. Furthermore, the set of dyadic spherical harmonics is built, which stands for the extension of the well-known spherical vector harmonics to the dyadic realm. Every dyadic field restricted on the unit sphere can be expanded in terms of these spherical dyadic harmonics. The orthogonality relations of these functions are determined in close form and this is the prerequisite for the fully analytic treatment of the boundary conditions involving the scattering problem under consideration.

  1. Revisiting Elastic Scattering of D(n, n)D reaction

    SciTech Connect

    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.

  2. Potentials for the α- 40,44,48Ca elastic scattering

    NASA Astrophysics Data System (ADS)

    Abdullah, M. N. A.; Idris, A. B.; Tariq, A. S. B.; Islam, M. S.; Das, S. K.; Uddin, M. A.; Mondal, A. S.; Basak, A. K.; Reichstein, I.; Sen Gupta, H. M.; Malik, F. B.

    2005-10-01

    The differential cross sections for the elastic scattering of α particles by 40,44,48Ca, over a wide range of incident energies, have been analyzed using a deep as well as shallow non-monotonic optical potential and compared with those using a squared Woods-Saxon (SWS) potential. The shallow non-monotonic potential exhibits a volume integral for the real part, characteristic of a molecular potential. The parameters of the SWS potential have also been obtained for α- 48Ca scattering. The parameters of the shallow non-monotonic potential calculated from the energy-density-formalism provide a satisfactory description of the elastic scattering data. The non-monotonic potentials, both deep and shallow, are found to yield consistently a lower value of the radius parameter of the real potential for 48Ca than that for 40Ca, in conformity with the observed magnitudes of the root-mean-square radii for the two nuclei. Both the potentials indicate that the semi-magic 44Ca behaves differently from the doubly-magic 40,48Ca, in agreement with the findings from the folding potentials. The dispersion effect arising from the causality principle has been investigated for the shallow non-monotonic α- 40Ca potential and is found to play a rather minor role in describing the elastic scattering data.

  3. 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%.

  4. Demonstration of a novel technique to measure two-photon exchange effects in elastic e±p scattering

    SciTech Connect

    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 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

  5. Demonstration of a novel technique to measure two-photon exchange effects in elastic e±p scattering

    DOE PAGESBeta

    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

  6. 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

  7. Elastic pp scattering from the optical point to past the dip: An empirical parametrization from ISR to the LHC

    NASA Astrophysics Data System (ADS)

    Fagundes, D. A.; Pancheri, G.; Grau, A.; Pacetti, S.; Srivastava, Y. N.

    2013-11-01

    We describe the main features of recent LHC data on elastic pp scattering through a simple parametrization to the amplitude, inspired by a model proposed by Barger and Phillips in 1973, comprised of two exponentials with a relative phase. Despite its simplicity, this parametrization reproduces two essential aspects of the elastic differential cross section: the well-known precipitous descent in the forward direction and a sharp “dip” structure. To include a complete description of data sets near -t=0, we correct the original parametrization. We examine two possibilities: the presence of the two-pion threshold singularity or a multiplicative factor reflecting the proton form factor. We find good descriptions of LHC7 and ISR data in either case. The form-factor model allows simple predictions for higher energies through asymptotic theorems and asymptotic sum rules in impact parameter space. We present predictions for this model at higher LHC energies, which can be used to test whether asymptotia is reached. The black-disk limit in this model is seen to be reached only for s˜106TeV.

  8. Elastic scattering and inversion for the spatially heterogeneous distribution of compliance of a single fracture

    NASA Astrophysics Data System (ADS)

    Minato, S.; Ghose, R.

    2013-12-01

    The elastdynamic response of a fracture is often modeled using the linear-slip model (LSM) for the fracture compliance. In earlier theoretical and laboratory studies, the distribution of compliance along the plane of a fracture has generally been assumed to be homogeneous. However, naturally occurring fractures are spatially heterogeneous, with the microscale properties varying along the fracture plane. The spatial heterogeneity of the microscale parameters along the fracture plane, e.g., roughness, contact area and distribution of fluid filled aperture, controls significantly the mechanical and hydraulic response of a fracture. When the fracture compliance is spatially heterogeneous, an incident elastic wavefield will be scattered at the fracture plane. This scattered wavefield contains information of the spatial heterogeneity of fracture compliance. In this study, we show through numerical modeling that the scattered elastic wavefield is sensitive to the spatial heterogeneity in compliance distribution. We find that the back-scattered elastic wavefield from a spatially heterogeneous fracture appears as the coda of the specular reflection, with amplitude differing from that for a homogenous fracture compliance. An analysis of the scattered wavefield does reveal the spatial heterogeneity along the fracture plane. In order to estimate the spatially heterogeneous compliance distribution, we have developed an inversion scheme. The scheme has the following two steps: (1) extrapolating the recorded back-scattered elastic wavefield and estimating the stress field at the fracture plane, and (2) solving the boundary condition of LSM using the estimated stress field. We illustrate this new method through numerical examples mimicking laboratory-scale measurements (Figure). In the low frequency, the estimated compliance distribution is smooth and inaccurate because of the presence of the evanescent waves. However, at the peak frequency, the compliance distribution can be

  9. Differential electron-Cu5+ elastic scattering cross sections extracted from electron emission in ion-atom collisions

    NASA Astrophysics Data System (ADS)

    Liao, C.; Hagmann, S.; Bhalla, C. P.; Grabbe, S. R.; Cocke, C. L.; Richard, P.

    1999-04-01

    We present a method of deriving energy and angle-dependent electron-ion elastic scattering cross sections from doubly differential cross sections for electron emission in ion-atom collisions. By analyzing the laboratory frame binary encounter electron production cross sections in energetic ion-atom collisions, we derive projectile frame differential cross sections for electrons elastically scattered from highly charged projectile ions in the range between 60° and 180°. The elastic scattering cross sections are observed to deviate strongly from the Rutherford cross sections for electron scattering from bare nuclei. They exhibit strong Ramsauer-Townsend electron diffraction in the angular distribution of elastically scattered electrons, providing evidence for the strong role of screening played in the collision. Experimental data are compared with partial-wave calculations using the Hartree-Fock model.

  10. 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.

  11. Elastic /ital p//sub /up arrow//p/sub /up arrow// scattering between 240 and 470 MeV

    SciTech Connect

    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.

  12. Neutron Elastic and Inelastic Scattering Cross Sections on ^NatFe and ^23Na

    NASA Astrophysics Data System (ADS)

    Kersting, Luke; Lueck, Collin J.; Hicks, S. F.; Crider, B. P.; McEllistrem, M. T.; Peters, E. E.; Vanhoy, J. R.

    2010-10-01

    Neutron elastic and inelastic scattering angular distributions from ^NatFe and ^23Na at incident neutron energies of 3.57 and 3.81 MeV have been measured at the University of Kentucky 7 MV Van de Graaff laboratory using neutron time-of-flight techniques. The neutron beam was produced using the ^3H(p,n)He^3reaction. The scattered neutrons were detected at angles between 20 and 150 in 10 intervals with a hexafluorbenzene detector located approximately 3 m from the scattering samples. Neutron scattering differential cross sections were deduced. These cross sections and their uncertainties are important for understanding neutron-induced reactions in fission reactors and are important for fission reactor criticality calculations.

  13. Quantum Multimode Model of Elastic Scattering from Bose-Einstein Condensates

    SciTech Connect

    Zin, P.; Chwedenczuk, J.; Trippenbach, M.; Veitia, A.; Rzazewski, K.

    2005-05-27

    Mean field approximation treats only coherent aspects of the evolution of a Bose-Einstein condensate. However, in many experiments some atoms scatter out of the condensate. We study a semianalytic model of two counterpropagating atomic Gaussian wave packets incorporating the dynamics of incoherent scattering processes. Within the model we can treat processes of the elastic collision of atoms into the initially empty modes, and observe how, with growing occupation, the bosonic enhancement is slowly kicking in. A condition for the bosonic enhancement effect is found in terms of relevant parameters. Scattered atoms form a squeezed state. Not only are we able to calculate the dynamics of mode occupation, but also the full statistics of scattered atoms.

  14. 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.

  15. Proton enhanced scattering and nuclear reaction analysis microcharacterization of ternary graphite-lithium-calcium intercalation compounds

    NASA Astrophysics Data System (ADS)

    Berger, P.; Pruvost, S.; Hérold, C.; Lagrange, P.

    2004-06-01

    Intercalation of lithium into graphite is of great interest, due to its largely expanded use as negative electrode material in the Li-ion batteries, especially the LiC 6 compound. Recently, the first ternary intercalation compounds associating lithium with a second metallic element were synthesized by immersing pyrographite platelet in a molten Ca-Li alloy. Photonic and neutronic diffractions on these graphite-lithium-calcium compounds reveal that lithium and calcium layers are intercalated between graphene sheets. However, the precise elemental composition still lacks. Chemical analysis gives an average composition but carbon is not measured in the same sample as calcium and lithium. Electron microprobe, SEM and TEM do not allow to determine lithium concentration and its distribution in these compounds. This paper reports the first elemental characterization of carbon-calcium-lithium intercalation compounds by means of nuclear microprobe. Using a 3.1 MeV proton beam, both lithium, calcium and carbon can be determined within a single measurement, from the 7Li(p,α) 4He nuclear reaction and from elastic scattering for calcium and carbon respectively. In the graphite-lithium-calcium system, three different intercalation compounds were synthesized, containing low to high lithium content. The mapping of the samples reveals lateral and also mainly in depth heterogeneity (along the c axis).

  16. Monte Carlo investigations of elastic scattering spectroscopy applied to latex spheres used as tissue phantoms

    SciTech Connect

    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.

  17. Elastic and inelastic scattering of /sup 16/O by /sup 26/Mg

    SciTech Connect

    Rotberg, V.H.; Mittig, W.

    1980-10-01

    Angular distributions and excitation functions for the elastic and inelastic (2/sup +/,1.81 MeV) scattering of /sup 16/O ions by /sup 26/Mg have been measured in the energy range from 22 up to 50 MeV. The data were analyzed in the coupled channel scheme with different potentials. The inelastic scattering data are found to be important to distinguish between optical model parameter sets. The deformation parameter delta/sub n/=..beta../sub n/R is extracted and found to be potential dependent. It is compared to the Coulomb deformation delta/sub C/.

  18. Elastic scattering of low energy electrons in partially ionized dense semiclassical plasma

    SciTech Connect

    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.

  19. Total reaction cross sections from elastic {alpha}-nucleus scattering angular distributions around the Coulomb barrier

    SciTech Connect

    Mohr, P.; Galaviz, D.; Fueloep, Zs.; Gyuerky, Gy.; Kiss, G. G.; Somorjai, E.

    2010-10-15

    The total reaction cross section {sigma}{sub reac} is a valuable measure for the prediction of {alpha}-induced reaction cross sections within the statistical model and for the comparison of scattering of tightly bound projectiles to weakly bound and exotic projectiles. Here we provide the total reaction cross sections {sigma}{sub reac} derived from our previously published angular distributions of elastic {alpha}-nucleus scattering on {sup 89}Y, {sup 92}Mo, {sup 112,124}Sn, and {sup 144}Sm at energies around the Coulomb barrier.

  20. Aspects of a dynamical gluon mass approach to elastic hadron scattering at LHC

    NASA Astrophysics Data System (ADS)

    Fagundes, D. A.; Luna, E. G. S.; Menon, M. J.; Natale, A. A.

    2012-07-01

    We discuss how the main features of the recent LHC data on elastic scattering can be described by a QCD-inspired formalism with a dynamical infrared mass scale. For this purpose new developments on a dynamical gluon mass approach are reported, with emphasis on a method to estimate uncertainty bounds in the predictions for the high-energy scattering observables. We investigate the effects due to the correlations among the fixed and free parameters involved and show that the bands of predictions are consistent with the recent data from the TOTEM experiment, including the forward quantities and the differential cross section up to the dip position.

  1. Breakup threshold anomaly in the elastic scattering of {sup 6}Li on {sup 27}Al

    SciTech Connect

    Figueira, J. M.; Niello, J. O. Fernandez; Abriola, D.; Arazi, A.; Capurro, O. A.; Barbara, E. de; Marti, G. V.; Heimann, D. Martinez; Negri, A. E.; Pacheco, A. J.; Padron, I.; Gomes, P. R. S.; Lubian, J.; Correa, T.; Paes, B.

    2007-01-15

    Elastic scattering of the weakly bound {sup 6}Li on {sup 27}Al was measured at near-barrier energies. The data analysis was performed using a Woods-Saxon shape optical potential and also using the double-folding Sao Paulo potential. The results show the presence of the breakup threshold anomaly (BTA), an anomalous behavior when compared with the scattering of tightly bound nuclei. This behavior is attributed to a repulsive polarization potential produced by the coupling to the continuum breakup states.

  2. Two Photon Exchange in Quasi-elastic and Deep-inelastic Scattering

    SciTech Connect

    Averett, Todd D.; Katich, Joseph; Zhao Bo

    2011-10-24

    In this paper, I present an overview and preliminary results from three experiments at Jefferson Lab that were recently completed using a {sup 3}He gas target with polarization oriented normal to the scattering plane of unpolarized incident electrons. A target single spin asymmetry was formed by periodically flipping the direction of the target spin. In the reaction {up_arrow}{sup 3}He(e,e'), the Born contribution is expected to be zero, giving direct sensitivity to two photon exchange. This asymmetry was measured in the quasi-elastic and deep-inelastic regimes with 0.1 < Q{sup 2} < 1.0 GeV{sup 2}. The asymmetry is predicted to decrease by two-orders of magnitude for deep-inelastic versus quasi-elastic scattering. Preliminary results from these experiments will be presented.

  3. Semiclassical description of the {sup 6}He+{sup 12}C elastic scattering

    SciTech Connect

    Bayrak, O. Boztosun, I.

    2011-01-15

    The results of the elastic scattering of {sup 6}He+{sup 12}C systemat E{sub Lab} = 18 MeV by using the barrier and internal wave decomposition of the S-matrix element within the framework of the WKB method are presented. This is the first detailed study for the interaction of the exotic {sup 6}He nucleus on different stable nuclei by using a semiclassicalmethod. In this paper, we show that in order to obtain the elastic scattering cross section of the {sup 6}He+{sup 12}C systemat energies close to the Coulomb barrier, it is vitally important to take into account the inner complex turning points in the calculations and the tunneling effects play a crucial role to explain the experimental data. The semiclassical results are compared with the experimental data as well as the quantum-mechanical one.

  4. Impact of 6Li resonances on the near-barrier elastic scattering with 144Sm

    NASA Astrophysics Data System (ADS)

    Camacho, A. Gómez; Diaz-Torres, A.; Gomes, P. R. S.; Lubian, J.

    2016-02-01

    Converged continuum discretized coupled-channel calculations of elastic-scattering differential cross sections for reactions induced by the 6Li projectile on the 144Sm target, at energies around the Coulomb barrier, are presented. The impact of the low-lying α -deuteron resonant states in 6Li (l =2 ,Jπ=3+,2+,1+ ) on those elastic angular distributions is quantified. This is done by two types of calculations, namely, (a) by omitting from the continuum energy spectrum all states where the resonances are constructed in the discretization process, and (b) by considering only the resonance discretized space. Dynamical polarization potentials are used for interpreting the effect of continuum couplings. Resonant couplings play a more significant role than nonresonance ones at back-scattering angles and at incident energies below the Coulomb barrier. However, their effect becomes weaker as the incident energy increases above the barrier energy.

  5. Elastic Scattering and Reaction Mechanisms of the Halo Nucleus {sup 11}Be around the Coulomb Barrier

    SciTech Connect

    Di Pietro, A.; Figuera, P.; Papa, M.; Santonocito, D.; Randisi, G.; Scuderi, V.; Amorini, F.; Fisichella, M.; Lattuada, M.; Pellegriti, M. G.; Rizzo, F.; Scalia, G.; Torresi, D.; Acosta, L.; Martel, I.; Perez-Bernal, F.; Borge, M. J. G.; Tengblad, O.; Vidal, A. Maira; Fraile, L. M.

    2010-07-09

    Collisions induced by {sup 9,10,11}Be on a {sup 64}Zn target at the same c.m. energy were studied. For the first time, strong effects of the {sup 11}Be halo structure on elastic-scattering and reaction mechanisms at energies near the Coulomb barrier are evidenced experimentally. The elastic-scattering cross section of the {sup 11}Be halo nucleus shows unusual behavior in the Coulomb-nuclear interference peak angular region. The extracted total-reaction cross section for the {sup 11}Be collision is more than double the ones measured in the collisions induced by {sup 9,10}Be. It is shown that such a strong enhancement of the total-reaction cross section with {sup 11}Be is due to transfer and breakup processes.

  6. K--Nucleus Elastic Scattering at IntermediateEnergies in the Isobar-Doorway Model

    NASA Astrophysics Data System (ADS)

    Toyama, F. M.

    1983-11-01

    The differential cross sections for the K--nucleus elastic scattering at about PK = 800 MeV/c are calculated in the phenomenological isobar-doorway model. The many-body corrections on Y* resonances in nuclei are represented by the resonance energy shift Δ E and width-modification factor β. The parametrizations given by Gopal et al. are used for the resonance amplitudes. The effects of Δ E and β on the cross sections are investigated in detail. The results are compared with the available experimental data for the K- elastic scattering on 12C and 40Ca at PK = 800 MeV/c. The calculated cross sections are in good agreement with the data. However, the cross sections are not very sensitive to Δ E and β.

  7. Elastic scattering of positrons on mercury: A negative-energy Dirac-Fock treatment

    SciTech Connect

    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.

  8. The scattering potential of partial derivative wavefields in 3D elastic orthorhombic media: An inversion prospective

    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.

  9. The scattering potential of partial derivative wavefields in 3-D elastic orthorhombic media: an inversion prospective

    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.

  10. Complete formalism for charge-symmetry tests in n-p elastic scattering

    NASA Astrophysics Data System (ADS)

    Moravcsik, Michael J.; Arash, Firooz

    1989-03-01

    A complete set of tests of charge symmetry in n-p elastic scattering is given in a formalism in which the number of tests, the types of observables appearing in the tests, and the characteristics of the spin-amplitudes parameters utilized in each test are easily identifiable and displayable. The results allow one to pinpoint the particular test which is theoretically the most interesting and experimentally the most advantageous.

  11. Limit on flavor-changing neutral currents from a measurement of neutrino-electron elastic scattering

    SciTech Connect

    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.).

  12. 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.

  13. Direct experimental reconstruction of the pp elastic scattering matrix at 579 MeV

    SciTech Connect

    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.

  14. Polarization transfer in wide-angle Compton scattering and single-pion photoproduction from the proton

    SciTech Connect

    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. 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.

  15. Polarization transfer in wide-angle Compton scattering and single-pion photoproduction from the proton

    DOE PAGESBeta

    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

  16. 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.

  17. Investigation of excited states in Mg22 via resonant elastic scattering of Na21+p and its astrophysical implications

    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.

  18. 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.

  19. 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.

  20. Production of γγ+2 jets from double parton scattering in proton-proton collisions at the LHC

    NASA Astrophysics Data System (ADS)

    Tao, Jun-Quan; Zhang, Si-Jing; Shen, Yu-Qiao; Fan, Jia-Wei; Chen, Guo-Ming; Chen, He-Sheng

    2015-12-01

    Cross sections for the production of pairs of photons plus two additional jets produced from double parton scattering in high-energy proton-proton collisions at the LHC are calculated for the first time. The estimates are based on the theoretical perturbative QCD predictions for the productions of γγ at next-to-next-to-leading-order, jet+jet and γ+jet at next-to-leading-order, for their corresponding single-scattering cross sections. The cross sections and expected event rates for γγ+2 jets from double parton scattering, after typical acceptance and selections, are given for proton-proton collisions with the collision energy \\sqrt{s}=13 TeV and integrated luminosity of 100 fb-1 planned for the following years, and also \\sqrt{s}=14 TeV with 3000 fb-1 of integrated luminosity as the LHC design. Supported by National Natural Science Foundation of China (11061140514, 11505208), China Ministry of Science and Technology (2013CB838700) and CAS Center for Excellence in Particle Physics (CCEPP)

  1. Development of Experiments to Measure D and 4He Charge Radii with Elastic Electron Scattering Method

    NASA Astrophysics Data System (ADS)

    Saudi, Sheikh

    Charge radii are one of the important physical characteristics to understand the electromagnetic structure of nuclei. For light nuclei, they are playing a more critical role to better understand the nucleon-nucleon interaction and test the existing models for bound states. Recent measurements of proton radius, done with muonic hydrogen spectroscopy, showed about 7 standard deviation lower than previous experimental results. This discrepancy triggered the so called "Proton Radius Puzzle" in physics world. Several groups are preparing to perform new experiments to extract the proton radius with better precision and model independent methods. It is equally important to perform new experiments for light nuclei, like deuteron (D) and helium-4 (4He), to verify the existing results for their radii. In this thesis work, we have developed an experimental method based on coincidence detection of the scattered electrons and recoiled light nuclei to measure the charge radii of deuteron and helium-4 with high accuracy.

  2. Elastic scattering and total reaction cross sections for the B8, Be7, and Li6 +12C systems

    NASA Astrophysics Data System (ADS)

    Barioni, A.; Zamora, J. C.; Guimarães, V.; Paes, B.; Lubian, J.; Aguilera, E. F.; Kolata, J. J.; Roberts, A. L.; Becchetti, F. D.; Villano, A.; Ojaruega, M.; Jiang, H.

    2011-07-01

    Angular distributions for the elastic scattering of B8, Be7, and Li6 on a C12 target have been measured at Elab=25.8, 18.8, and 12.3 MeV, respectively. The analyses of these angular distributions have been performed in terms of the optical model using Woods-Saxon and double-folding type potentials. The effect of breakup in the elastic scattering of 8B+12C is investigated by performing coupled-channels calculations with the continuum discretized coupled-channel method and cluster-model folding potentials. Total reaction cross sections were deduced from the elastic-scattering analysis and compared with published data on elastic scattering of other weakly and tightly bound projectiles on C12, as a function of energy. With the exception of He4 and O16, the data can be described using a universal function for the reduced cross sections.

  3. Measurements of anomalous elastic scattering of 59.54-keV photons

    SciTech Connect

    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.}

  4. Phase Shift Analyses of pp Elastic Scattering between 500 and 800 MeV

    NASA Astrophysics Data System (ADS)

    Nagata, J.; Yoshino, H.; Matsuda, M.

    1995-03-01

    The single-energy phase-shift analyses of pp elastic scattering have been made by using double-spin and triple-spin correlation parameters measured at SIN in the incident energy region TL = 447-580 MeV, and at LAMPF at TL = 735 MeV. The scattering amplitudes have been almost uniquely determined at TL = 500, 530, 560, 580 and 735 MeV. The Argand diagrams of 1D2-, 3P2- and 3F3-wave amplitudes show counter clockwise behavior. The obtained I = 1 amplitudes in the present analysis will contribute to the determination of the I = 0 amplitudes of np scattering in the same energy region.

  5. Effect of the tensor part of Skyrme interaction on the description of elastic nucleon-nucleus scattering on the basis of the optical model

    SciTech Connect

    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.

  6. Antiplane wave scattering from a cylindrical cavity in pre-stressed nonlinear elastic media

    PubMed Central

    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

  7. Spins and parities of the odd-A P isotopes within a relativistic mean-field model and elastic magnetic electron-scattering theory

    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.

  8. How to distinguish elastically scattered light from Stokes shifted light for solid-state lighting?

    NASA Astrophysics Data System (ADS)

    Meretska, M. L.; Lagendijk, A.; Thyrrestrup, H.; Mosk, A. P.; IJzerman, W. L.; Vos, W. L.

    2016-03-01

    We have studied the transport of light through phosphor diffuser plates that are used in commercial solid-state lighting modules (Fortimo). These polymer plates contain YAG:Ce+3 phosphor particles that both elastically scatter and Stokes shift light in the visible wavelength range (400-700 nm). We excite the phosphor with a narrowband light source and measure spectra of the outgoing light. The Stokes shifted light is spectrally separated from the elastically scattered light in the measured spectra, and using this technique, we isolate the elastic transmission of the plates. This result allows us to extract the transport mean free path ltr over the full wavelength range by employing diffusion theory. Simultaneously, we determine the absorption mean free path labs in the wavelength range 400 to 530 nm where YAG:Ce+3 absorbs. The diffuse absorption (μa=1/labs ) spectrum is qualitatively similar to the absorption coefficient of YAG:Ce+3 in powder, with the diffuse spectrum being wider than the absorption coefficient. We propose a design rule for the solid-state lighting diffuser plates.

  9. Multiple-scattering distributions and angular dependence of the energy loss of slow protons in copper and silver

    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.

  10. Multiple-scattering distributions and angular dependence of the energy loss of slow protons in copper and silver

    SciTech Connect

    Cantero, E. D.; Lantschner, G. H.; Eckardt, J. C.; Lovey, F. C.; Arista, N. R.

    2010-04-15

    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){proportional_to}r{sup -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.

  11. Handling the Handbag Diagram in Compton Scattering on the Proton

    SciTech Connect

    Miller, Gerald A.

    2004-02-25

    Poincare invariance, gauge invariance, conservation of parity and time reversal invariance are respected in an impulse approximation evaluation of the handbag diagram. Proton wave functions, previously constrained by comparison with measured form factors, that incorporate the influence of quark transverse and orbital angular momentum (and the corresponding violation of proton helicity conservation) are used. Computed cross sections are found to be in reasonably good agreement with early measurements. The helicity correlation between the incident photon and outgoing proton, K{sub LL}, is both large and positive at back angles. For photon laboratory energies of {le} 6 GeV, we find that K{sub LL} {ne} A{sub LL}, D{sub LL} {ne} 1, and that the polarization P can be large.

  12. Evidence for Non-Exponential Differential Cross-Section of pp Elastic Scattering at Low |t| and √s = 8 TeV by TOTEM

    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.

  13. Model-independent extraction of the proton charge radius from electron scattering

    SciTech Connect

    Hill, Richard J.; Paz, Gil

    2010-12-01

    Constraints from analyticity are combined with experimental electron-proton scattering data to determine the proton charge radius. In contrast to previous determinations, we provide a systematic procedure for analyzing arbitrary data without model-dependent assumptions on the form-factor shape. We also investigate the impact of including electron-neutron scattering data, and {pi}{pi}{yields}NN data. Using representative data sets we find r{sub E}{sup p}=0.870{+-}0.023{+-}0.012 fm using just proton scattering data; r{sub E}{sup p}=0.880{sub -0.020}{sup +0.017{+-}}0.007 fm adding neutron data; and r{sub E}{sup p}=0.871{+-}0.009{+-}0.002{+-}0.002 fm adding {pi}{pi} data. The analysis can be readily extended to other nucleon form factors and derived observables.

  14. Quasi-elastic neutron scattering studies of protein dynamics. Progress report, November 1, 1992--May 25, 1993

    SciTech Connect

    Rorschach, H.E.

    1993-05-25

    Results that shed new light on the study of protein dynamics were obtained by quasi-elastic neutron scattering. The triple axis instrument H-9 supplied by the cold source was used to perform a detailed study of the quasi-elastic spectrum and the Debye-Waller factor for trypsin in powder form, in solution, and in crystals. A preliminary study of myoglobin crystals was also done. A new way to view the results of quasi-elastic scattering experiments is sketched, and the data on trypsin are presented and analyze according to this new picture.

  15. A new way to calculate scattering of acoustic and elastic waves. I - Theory illustrated for scalar waves. II - Application to elastic waves scattered from voids and fixed rigid obstacles

    NASA Astrophysics Data System (ADS)

    Visscher, W. M.

    1980-02-01

    The paper presents a new method of calculation of elastic and acoustic wave scattering. The method of optimal truncation (MOOT) uses a family of integral equations solved by matrix methods; the scattered wave is expanded in a truncated series of eigenfunctions of the unperturbed wave equation, and expansion coefficients are determined by requiring that the mean square of the deviance from the boundary conditions at the surface of the scatterer be minimized. This results in matrix equations for the scattered amplitudes which can be easily solved; the method can compute the scattering of acoustic, elastic, or electromagnetic waves from defects which are internally piecewise homogeneous, so that conditions on the wave function derivatives and values at the boundaries characterize the scatterers.

  16. Proton and antiproton production in deep inelastic muon-nucleon scattering at 280 GeV

    NASA Astrophysics Data System (ADS)

    Arneodo, M.; Arvidson, A.; Aubert, J. J.; Badelek, B.; Beaufays, J.; Bee, C. P.; Benchouk, C.; Berghoff, G.; Bird, I.; Blum, D.; Böhm, E.; de Bouard, X.; Brasse, F. W.; Braun, H.; Broll, C.; Brown, S.; Brück, H.; Calen, H.; Chima, J. S.; Ciborowski, J.; Clifft, R.; Coignet, G.; Combley, F.; Coughlan, J.; D'Agostini, G.; Dahlgren, S.; Dengler, F.; Derado, I.; Dreyer, T.; Drees, J.; Düren, M.; Eckardt, V.; Edwards, A.; Edwards, M.; Ernst, T.; Eszes, G.; Favier, J.; Ferrero, M. I.; Figiel, J.; Flauger, W.; Foster, J.; Gabathuler, E.; Gajewski, J.; Gamet, R.; Gayler, J.; Geddes, N.; Grafström, P.; Grard, F.; Haas, J.; Hagberg, E.; Hasert, F. J.; Hayman, P.; Heusse, P.; Jaffré, M.; Jacholkowska, A.; Janata, F.; Jansco, G.; Johnson, A. S.; Kabuss, E. M.; Kellner, G.; Korbel, V.; Krüger, A.; Krüger, J.; Kullander, S.; Landgraf, U.; Lanske, D.; Loken, J.; Long, K.; Maire, M.; Malecki, P.; Manz, A.; Maselli, S.; Mohr, W.; Montanet, F.; Montgomery, H. E.; Nagy, E.; Nassalski, J.; Norton, P. R.; Oakham, F. G.; Osborne, A. M.; Pascaud, C.; Pawlik, B.; Payre, P.; Peroni, C.; Peschel, H.; Pessard, H.; Pettingale, J.; Pietrzyk, B.; Poensgen, B.; Pötsch, M.; Renton, P.; Ribarics, P.; Rith, K.; Rondio, E.; Sandacz, A.; Scheer, M.; Schlagböhmer, A.; Schiemann, H.; Schmitz, N.; Schneegans, M.; Scholz, M.; Schouten, M.; Schröder, T.; Schultze, K.; Sloan, T.; Stier, H. E.; Studt, M.; Taylor, G. N.; Thénard, J. M.; Thompson, J. C.; de La Torre, A.; Toth, J.; Urban, L.; Wallucks, W.; Whalley, M.; Wheeler, S.; Williams, W. S. C.; Wimpenny, S. J.; Windmolders, R.; Wolf, G.

    1987-12-01

    New results on proton and antiproton production in the target and current fragmentation regions of high energy muon-nucleon scattering are presented. Proton and antiproton production is investigated as a function of Feynman x and rapidity. No significant difference is observed between production on hydrogen and deuterium targets. Correlations between pp,pbar p andbar pbar p pairs are analysed and the results are compared with the predictions of the Lund fragmentation model.

  17. Elastic scattering and fusion cross sections for {sup 7}Be,{sup 7}Li+{sup 27}Al systems

    SciTech Connect

    Kalita, K.; Verma, S.; Singh, R.; Das, J.J.; Jhingan, A.; Madhavan, N.; Nath, S.; Varughese, T.; Sugathan, P.; Parkar, V.V.; Mahata, K.; Ramachandran, K.; Shrivastava, A.; Chatterjee, A.; Kailas, S.; Barua, S.; Basu, P.; Majumdar, H.; Sinha, M.; Bhattacharya, R.

    2006-02-15

    Quasi-elastic-scattering and transfer reaction cross-section measurements were made for the {sup 7}Be+{sup 27}Al system at E{sub lab}=17, 19, and 21 MeV in the angular range {theta}{sub c.m.}=12 deg. An optical model (OM) analysis of the quasi-elastic scattering data was carried out. The fusion cross sections were derived at these energies by subtraction of the integrated transfer cross sections from the reaction cross sections obtained from the fits to quasi-elastic-scattering data. These fusion cross sections were found to be consistent with those obtained from the coupled-channels calculations. Elastic scattering and fusion cross sections were measured for the {sup 7}Li+{sup 27}Al system at E{sub lab}=10, 13, 16, 19, and 24 MeV. For elastic scattering the angular coverages were in the {theta}{sub lab}=12 deg. - 72 deg. range and for fusion the {alpha}-evaporation spectra from the compound nucleus were measured in the angular range {theta}{sub lab}=52 deg. - 132 deg. (142 deg. at 10 MeV). The elastic-scattering angular distributions were subjected to OM analysis. The {alpha}-evaporation spectra were reproduced with the statistical model calculations, and the fusion cross sections were extracted from them. The fusion cross sections were also extracted by subtraction of the integrated inelastic-scattering cross sections from the reaction cross sections obtained from the OM fits to the elastic-scattering data, and these fusion data were found to be consistent. The CCDEF calculations describe these data quite well. A comparison of the fusion data for the {sup 7}Be+{sup 27}Al and {sup 7}Li+{sup 27}Al systems shows a similar and consistent behavior.

  18. Differential Cross Sections for Neutron Elastic and Inelastic Scattering on 23Na

    NASA Astrophysics Data System (ADS)

    Vanhoy, J. R.; Hicks, S. F.; Chakraborty, A.; Champine, B. R.; Combs, B.; Crider, B. P.; Kersting, L. J.; Kumar, A.; Lueck, C. J.; McDonough, P. J.; McEllistrem, M. T.; Peters, E. E.; Prados-Estévez, F. M.; Sidwell, L.; Sigillito, A.; Watts, D. W.; Yates, S. W.

    2014-03-01

    Measurements of neutron elastic and inelastic scattering from 23Na have been performed for sixteen incident neutron energies above 1.5 MeV with the 7-MV University of Kentucky Accelerator using the 3H(p,n) reaction as the neutron source. These measurements were complemented by γ-ray excitation functions using the (n,n'γ) reaction. The time-of-flight technique is employed for background reduction in both neutron and γ- ray measurements and for determining the energy of the scattered neutrons. Cross section determinations support fuel cycle and structural materials research and development. Previous reaction model evaluations [1] relied primarily on total cross sections and four (n,n0) and (n,n1) angular distributions in the En = 5 to 9 MeV range. The inclusion of more inelastic channels at lower neutron energies provides additional information on direct couplings between elastic and inelastic scattering as a function of angular momentum transfer. Reaction model calculations examining direct collective and statistical properties were performed.

  19. A joint theoretical and experimental study for elastic electron scattering from 1,4-dioxane.

    PubMed

    Palihawadana, P; Sullivan, J P; Buckman, S J; Masín, Z; Gorfinkiel, J D; Blanco, F; García, G; Brunger, M J

    2013-07-01

    We present results of measurements and calculations of elastic electron scattering from 1,4-dioxane in the energy range of 0-1000 eV. Absolute differential and integral elastic cross sections have been measured using a crossed electron-molecule beam spectrometer and the relative flow technique, at four energies in the 10-30 eV range and for scattered electrons in the angular range 20°-129°. The measured cross sections are compared with results from R-matrix computations, at the static exchange plus polarization level, calculated at energies between 0-20 eV, and with calculations employing the independent atom model with the screening corrected additivity rule (IAM-SCAR). Those latter computations were conducted at energies between 1 and 1000 eV. Agreement between the measured and R-matrix cross sections was typically found to be good at all common energies, whereas agreement with IAM-SCAR was satisfactory only at 30 eV. To the best of our knowledge, the present results are the first absolute data to be published in the literature for this scattering system. PMID:23822304

  20. Quasi-Elastic Neutron Scattering Studies of the Slow Dynamics of Supercooled and Glassy Aspirin

    SciTech Connect

    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.

  1. 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.

  2. 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.

  3. Standardized treatment planning methodology for passively scattered proton craniospinal irradiation

    PubMed Central

    2013-01-01

    Background As the number of proton therapy centers increases, so does the need for studies which compare proton treatments between institutions and with photon therapy. However, results of such studies are highly dependent on target volume definition and treatment planning techniques. Thus, standardized methods of treatment planning are needed, particularly for proton treatment planning, in which special consideration is paid to the depth and sharp distal fall-off of the proton distribution. This study presents and evaluates a standardized method of proton treatment planning for craniospinal irradiation (CSI). Methods We applied our institution’s planning methodology for proton CSI, at the time of the study, to an anatomically diverse population of 18 pediatric patients. We evaluated our dosimetric results for the population as a whole and for the two subgroups having two different age-specific target volumes using the minimum, maximum, and mean dose values in 10 organs (i.e., the spinal cord, brain, eyes, lenses, esophagus, lungs, kidneys, thyroid, heart, and liver). We also report isodose distributions and dose-volume histograms (DVH) for 2 representative patients. Additionally we report population-averaged DVHs for various organs. Results The planning methodology here describes various techniques used to achieve normal tissue sparing. In particular, we found pronounced dose reductions in three radiosensitive organs (i.e., eyes, esophagus, and thyroid) which were identified for optimization. Mean doses to the thyroid, eyes, and esophagus were 0.2%, 69% and 0.2%, respectively, of the prescribed dose. In four organs not specifically identified for optimization (i.e., lungs, liver, kidneys, and heart) we found that organs lateral to the treatment field (lungs and kidneys) received relatively low mean doses (less than 8% of the prescribed dose), whereas the heart and liver, organs distal to the treatment field, received less than 1% of the prescribed dose

  4. 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.

  5. 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.

  6. The SEXTANTS beamline at SOLEIL: a new facility for elastic, inelastic and coherent scattering of soft X-rays

    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.

  7. Imaging the proton via hard exclusive production in diffractive pp scattering

    SciTech Connect

    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).

  8. Jet production in muon-proton and muon-nuclei scattering at Fermilab-E665

    SciTech Connect

    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.

  9. Comparison of multiplicity distributions to the negative binomial distribution in muon-proton scattering

    NASA Astrophysics Data System (ADS)

    Arneodo, M.; Arvidson, A.; Aubert, J. J.; Badełek, B.; Beaufays, J.; Bee, C. P.; Benchouk, C.; Berghoff, G.; Bird, I.; Blum, D.; Böhm, E.; de Bouard, X.; Brasse, F. W.; Braun, H.; Broll, C.; Brown, S.; Brück, H.; Calen, H.; Chima, J. S.; Ciborowski, J.; Clifft, R.; Coignet, G.; Combley, F.; Coughlan, J.; D'Agostini, G.; Dahlgren, S.; Dengler, F.; Derado, I.; Dreyer, T.; Drees, J.; Düren, M.; Eckardt, V.; Edwards, A.; Edwards, M.; Ernst, T.; Eszes, G.; Favier, J.; Ferrero, M. I.; Figiel, J.; Flauger, W.; Foster, J.; Ftáčnik, J.; Gabathuler, E.; Gajewski, J.; Gamet, R.; Gayler, J.; Geddes, N.; Grafström, P.; Grard, F.; Haas, J.; Hagberg, E.; Hasert, F. J.; Hayman, P.; Heusse, P.; Jaffré, M.; Jachołkowska, A.; Janata, F.; Jancsó, G.; Johnson, A. S.; Kabuss, E. M.; Kellner, G.; Korbel, V.; Krüger, J.; Kullander, S.; Landgraf, U.; Lanske, D.; Loken, J.; Long, K.; Maire, M.; Malecki, P.; Manz, A.; Maselli, S.; Mohr, W.; Montanet, F.; Montgomery, H. E.; Nagy, E.; Nassalski, J.; Norton, P. R.; Oakham, F. G.; Osborne, A. M.; Pascaud, C.; Pawlik, B.; Payre, P.; Peroni, C.; Peschel, H.; Pessard, H.; Pettinghale, J.; Pietrzyk, B.; Pietrzyk, U.; Pönsgen, B.; Pötsch, M.; Renton, P.; Ribarics, P.; Rith, K.; Rondio, E.; Sandacz, A.; Scheer, M.; Schlagböhmer, A.; Schiemann, H.; Schmitz, N.; Schneegans, M.; Schneider, A.; Scholz, M.; Schröder, T.; Schultze, K.; Sloan, T.; Stier, H. E.; Studt, M.; Taylor, G. N.; Thénard, J. M.; Thompson, J. C.; de La Torre, A.; Toth, J.; Urban, L.; Urban, L.; Wallucks, W.; Whalley, M.; Wheeler, S.; Williams, W. S. C.; Wimpenny, S. J.; Windmolders, R.; Wolf, G.

    1987-09-01

    The multiplicity distributions of charged hadrons produced in the deep inelastic muon-proton scattering at 280 GeV are analysed in various rapidity intervals, as a function of the total hadronic centre of mass energy W ranging from 4 20 GeV. Multiplicity distributions for the backward and forward hemispheres are also analysed separately. The data can be well parameterized by binomial distributions, extending their range of applicability to the case of lepton-proton scattering. The energy and the rapidity dependence of the parameters is presented and a smooth transition from the negative binomial distribution via Poissonian to the ordinary binomial is observed.

  10. Evidence that scattering due to nonlinear elasticity contributes to coda waves.

    NASA Astrophysics Data System (ADS)

    Calisto, I.; Bataille, K.; Stiller, M.; Mechie, J.

    2008-12-01

    Different factors might affect the propagation of seismic waves producing scattering, including heterogeneities and nonlinear elasticity. A key difference between these two factors is the dependence of the strength of the scattered waves on the strength of the incident wave, being linear for the former and nonlinear for the latter. A detailed study of these dependences using TIPTEQ data, where more than hundred explosions were recorded on 180 three-compomnent stations, most of them in the distance range of approximately 0-18 km (and a few far-offset explosions up to 100 km distance) shows that this dependence is nonlinear. Data were analysed in the following way: (i) the envelope of a bandpass filter between 10 and 40 Hz was obtained for a large number of stations from different ranges and charges of shots, (ii) for these distances we modeled the envelope considering the nonlinear elasticity. The shapes of the theoretical and observed envelopes were in general very similar, and a scale factor for each case was obtained considering the best fit of its complete envelope, (iii) since this scale factor depends mainly on the size of the explosion, we computed the ratio (R) of the scale factor (A) for different size explosions at fixed distances, for distances varying between 0 and 50 km. (iv) we computed the power (p) of the dependence of the ratio (R) on the ratio of charges. (R=(A1/ A2)=(/charge1/charge2/)p). We observe in general that p>1 and for distances between 14 and 18 km, and charges of 75 and 150 kg, the value of p=1.8 ± 0.4. This shows clearly that nonlinear elasticity is an important factor contributing to seismic wave scattering.

  11. Spherical momentum distribution of the protons in hexagonal ice from modeling of inelastic neutron scattering data

    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.

  12. Study of the vec P + {}3vec he Backward Elastic Scattering

    NASA Astrophysics Data System (ADS)

    Hatanaka, K.; Sakemi, Y.; Wakasa, T.; Yoshida, H. P.; Kamiya, J.; Shimizu, Y.; Okamura, H.; Uesaka, T.; Suda, K.; Ueno, H.; Sagara, K.; Ishida, T.; Ishikawa, S.; Tanifuji, M.; Kobushkin, A. P.; Strokovsky, E. A.

    2003-04-01

    We will measure the differential cross section and the spin-spin correlation Cyy of the p-3He backward elastic scattering at 200 - 400 MeV and at the Research Center for Nuclear Physics (RCNP), Osaka University. There are several cross section data but mainly at energies higher than 400 MeV. Our calculations show that at the energy region of the RCNP Ring Cyclotron, the cross section and spin-spin correlations are sensitive to the 3He wave function and the reaction mechanisms.

  13. Double folding cluster potential for {sup 12}C+{sup 12}C elastic scattering

    SciTech Connect

    Hassanain, M. A.; Ibraheem, Awad A.; Farid, M. El-Azab

    2008-03-15

    Using the alpha ({alpha})-cluster structure of {sup 12}C nucleus, two versions of the {sup 12}C+{sup 12}C real double folded optical potentials have been generated based upon effective {alpha}-{alpha},{alpha}-nucleon (N) and N-N interactions. The obtained potentials, in conjunction with shallow phenomenological Woods-Saxon imaginary parts, successfully reproduce the elastic scattering differential cross section for 12 sets of data over the broad energy range 70-360 MeV. No renormalization of the real folded potentials is required to fit the data. The energy dependence of the extracted real and imaginary volume integrals and total reaction cross section is investigated.

  14. Elastic scattering for the system {sup 6}Li+p at near barrier energies with MAGNEX

    SciTech Connect

    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.

  15. Parity violation in nucleon-nucleus elastic scattering within a phenomenological single particle model

    NASA Astrophysics Data System (ADS)

    Avishai, Y.

    1983-08-01

    Using a phenomenological neutron-40Ca strong and weak potentials at low energy we calculate the asymmetry A in the total cross section between positive and negative incoming helicity states, the asymmetry I in the differential elastic cross sections, and the neutron spin rotation angle dφdz. In general, max |IA|>>1. Taking into account the relevant cross sections, it turns out that sometimes, measuring I (instead of A) can save a substantial amount of beam time. NUCLEAR REACTIONS Parity violation, asymmetries, neutron spin rotation, σ-->.p--> interactions, neutron-nucleus scattering, phenomenological weak and strong nucleon-nucleus optical potential.

  16. Short Range Correlations in Nuclei at Large xbj through Inclusive Quasi-Elastic Electron Scattering

    SciTech Connect

    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

  17. 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

  18. Elastic scattering of {sup 9}Li on {sup 208}Pb at energies around the Coulomb barrier

    SciTech Connect

    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.

  19. Elastic Scattering of Ultracold 133Cs and 85Rb Atoms in Triplet State

    NASA Astrophysics Data System (ADS)

    Sun, Jin-Feng; Hu, Qiu-Bo; Zhu, Zun-Lue; Wang, Xiao-Fei; Zhang, Ji-Cai

    2007-06-01

    Elastic scattering properties of the ultracold interaction for the triplet state of 133Cs and 85Rb atoms are studied using two kinds of potentials by the same phase Φ. One is the interpolation potential, and another is Lennard-Jones potential (LJ12,6). The radial Schrödinger equation is also solved using two computational methods, the semiclassical method (WKB), and the Numerov method. Our results are found to be in an excellent agreement with the more recent theoretical values. It shows that the two potentials and methods are applicable for studying ultracold collisions between the mixing alkali atoms.

  20. Elastic scattering research at a 1 MW long pulse spallation neutron source

    SciTech Connect

    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.

  1. Elastic and inelastic vibrational cross sections for positron scattering by carbon monoxide

    NASA Astrophysics Data System (ADS)

    Tenfen, W.; Arretche, F.; Michelin, S. E.; Mazon, K. T.

    2015-11-01

    The vibrational cross sections of the CO molecule induced by positron impact is the focus of this work. The positron-molecule interaction is represented by the static potential plus a model potential designed to take into account the positron-target correlations. To calculate the vibrational cross sections, we applied the multichannel version of the continued fractions method in the close-coupling scheme. We present vibrational excitation cross sections and elastic ones, for the ground and excited vibrational states. The results are interpreted in terms of the vibrational coupling-scheme used in the scattering model.

  2. Importance of elastic scattering to particle direction determination in Monte Carlo calculations of DT reactions in flight

    SciTech Connect

    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.

  3. Spin correlation parameter Cyy of p+He3 elastic backward scattering

    NASA Astrophysics Data System (ADS)

    Shimizu, Y.; Hatanaka, K.; Tameshige, Y.; Adachi, T.; Fujita, K.; Matsubara, H.; Okamura, H.; Tamii, A.; Kobushkin, A. P.; Kawabata, T.; Sasamoto, Y.; Suda, K.; Uesaka, T.; Itoh, K.; Sakemi, Y.; Wakui, T.; Uchida, M.; Kudoh, T.; Sagara, K.; Wakasa, T.; Yoshida, H. P.; Shimbara, Y.; Strokovsky, E. A.; Ishikawa, S.; Tanifuji, M.

    2007-10-01

    We measured the differential cross section and the spin correlation parameter Cyy of the p→+3He→ elastic backward scattering at 200, 300, and 400 MeV at θ=180° in the center-of-mass frame to study the mechanism of the reaction and to examine the validity of the He3 wave functions based on two different realistic two-body forces. This is the first measurement of the spin correlation parameter Cyy of the p→+3He→ 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 Cyy 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.

  4. Spin Correlation Parameter Cyy of p + 3He Elastic Backward Scattering at Intermediate Energy

    NASA Astrophysics Data System (ADS)

    Shimizu, Y.; Hatanaka, K.; Adachi, T.; Itoh, K. F. K.; Kawabata, T.; Kudoh, T.; Ohira, H. M. H.; Okamura, H.; Sagara, K.; Sasamoto, Y. S. Y.; Yoshida, Y. S. H. P.; Suda, K.; Tomiyama, Y. T. A. T. M.; Uesaka, M. U. T.; Wakasa, T.; Wakui, T.

    2005-08-01

    It is possible to use nucleon-nucleus scattering as a probe of the spin structure of nuclei, since target related observables are extremely sensitive to small spin-dependent parts of the target wave function. In addition, one can gain information about the nucleon-nucleus reaction mechanism, the spin dependence of the nucleon-nucleon interaction in the nuclear medium, and off-shell behavior of the nucleon-nucleon amplitudes. For 3He(p,3He)p elastic backward scattering (EBS), only a small amount of data exists for the differential cross-section and none exists for spin-dependent observables. We have developed a spin-exchange polarised 3He target and measured the spin correlation parameter Cyy at 200, 300, and 400 MeV.

  5. Spin Correlation Parameter Cyy of p + 3He Elastic Backward Scattering at Intermediate Energy

    NASA Astrophysics Data System (ADS)

    Shimizu, Y.; Hatanaka, K.; Kobushkin, A. P.; Adachi, T.; Fujita, K.; Itoh, K.; Kawabata, T.; Kudoh, T.; Matsubara, H.; Ohira, H.; Okamura, H.; Sagara, K.; Sakemi, Y.; Sasamoto, Y.; Shimbara, Y.; Yoshida, H. P.; Suda, K.; Tameshige, Y.; Tamii, A.; Tomiyama, M.; Uchida, M.; Uesaka, T.; Wakasa, T.; Wakui, T.

    2007-01-01

    It is possible to use nucleon-nucleus scattering as a probe of the spin structure of the nuclei since target related observables are extremely sensitive to spin dependent parts of the target wave function. In addition, one can gain information about the nucleon-nucleus reaction mechanism, the spin dependent nucleon-nucleon interaction in the nuclear medium, and off-shell behavior of the nucleon-nucleon amplitudes. For 3He(p,3He)p elastic backward scattering, only small amount of data points exist for the differential cross section and no data exist for spin dependent observables. We developed a spin exchange type polarized 3He target and measured the spin correlation parameter Cyy at 200, 300, and 400 MeV.

  6. Characteristic Features of Water Dynamics in Restricted Geometries Investigated with Quasi-Elastic Neutron Scattering

    DOE PAGESBeta

    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

  7. Characteristic Features of Water Dynamics in Restricted Geometries Investigated with Quasi-Elastic Neutron Scattering

    SciTech Connect

    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.

  8. Drift-pots for small angle elastic scattering at the fermilab collider

    NASA Astrophysics Data System (ADS)

    Amos, N.; Baker, W.; Bertani, M.; Block, M.; DeSalvo, R.; Dimitryiannis, D.; Donati, A.; Eartly, D.; Ellsworth, R.; Giacomelli, G.; Goodman, J.; Lennox, A.; Maleyran, R.; Manarin, A.; Mondardini, M.; Orear, J.; Pruss, S.; Rubinstein, R.; Shukla, S.; Yodh, G.; York, T.; Zucchelli, S.

    1986-12-01

    In order to measure the small angle p- overlinep scattering at the Fermilab Tevatron collider we developed very small drift chambers integrated with thin-wall roman pots. We named them drift-pots. The drift-pots are active 100 μm from the vacuum of the beam with an expected resolution of 60 μm in the drift direction and 250 μm in charge division. They are radiation resistant detectors intrinsically insensitive to the beam pickup pulses and their multiple hit readout capability will allow us to push them into the beam halo where p- overlinep Coulomb elastic scattering dominates. For our application, we belive the drift-pots, are superior to state of the art silicon detectors.

  9. Characteristic features of water dynamics in restricted geometries investigated with quasi-elastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Osti, N. C.; Coté, A.; Mamontov, E.; Ramirez-Cuesta, A.; Wesolowski, D. J.; Diallo, S. O.

    2016-02-01

    Understanding the molecular behavior of water in spatially restricted environments is key 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.

  10. 26Al+p elastic and inelastic scattering reactions and galactic abundances of 26Al

    NASA Astrophysics Data System (ADS)

    Pittman, S. T.; Bardayan, D. W.; Chae, K. Y.; Chipps, K. A.; Jones, K. L.; Kozub, R. L.; Matei, C.; Matos, M.; Moazen, B. H.; Nesaraja, C. D.; O'Malley, P. D.; Pain, S. D.; Parker, P. D.; Peters, W. A.; Shriner, J. F., Jr.; Smith, M. S.

    2012-06-01

    Galactic 26Al is the first radioactive nucleus to be positively identified by γ-ray astronomy with detection of the 1.809 MeV γ ray associated with its decay. This nucleus is destroyed in astrophysical environments in the 26Al(p,γ)27Si and inelastic 26Al+p scattering reactions where properties of 27Si levels determine reaction rates. To investigate these properties, elastic and inelastic 26Al+p scattering reactions were measured between Ec.m. = 0.5-1.5 MeV at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL). A candidate for a new resonance in the 26Al(p,γ)27Si reaction was identified. Upper limits were also set on the strengths of postulated resonances and on the cross section of the inelastic reaction, but there is little effect on current reaction rate calculations.

  11. Elastic properties of polymer-doped dilute lamellar phases: A small-angle neutron scattering study

    NASA Astrophysics Data System (ADS)

    Ficheux, M.-F.; Bellocq, A.-M.; Nallet, F.

    2001-03-01

    We investigate experimentally, using small-angle neutron scattering the elastic properties of polymer-doped dilute lamellar phases. In our system the polymer is water-soluble but nevertheless partially adsorbs onto the negatively charged surfactant bilayers. The effective polymer-mediated interaction between bilayers is less repulsive than the weakly screened electrostatic interaction that prevails at zero polymer content. It even becomes attractive in some regions of the phase diagram. Small-angle neutron scattering allows us to measure directly the Caillé exponent η characterizing the bilayer fluctuations in lamellar (smectic A) phases, and thus indirectly estimate the compression modulus bar{B} as a measure of the strength of the bilayer-bilayer interactions. The compression modulus appears to be vanishing at a point located on the lamellar-lamellar phase separation boundary, a candidate critical point.

  12. Anomalous elastic scattering of x-ray photon by an atom with an open shell

    NASA Astrophysics Data System (ADS)

    Hopersky, A. N.; Petrov, I. D.; Nadolinsky, A. M.; Yavna, V. A.; Koneev, R. V.

    2004-08-01

    In the non-relativistic approximation for the wavefunctions of the one-electron states and in the dipole approximation for the scattering amplitude the effect of relaxation of atomic shells in the field of core vacancies, multiplet splitting, Auger and radiative vacancy decays and virtual processes of one-photon double excitation/ionization from the atomic ground state on the differential cross section of anomalous elastic scattering of the linearly polarized x-ray photon by the copper atom near its 1s-shell ionization threshold are studied. The results of calculations are found to be in agreement with the high-precision synchrotron radiation experiment by Arp et al (1993 J. Phys. B: At. Mol. Opt. Phys. 26 4381).

  13. Ionization, photoelectron dynamics and elastic scattering in relativistic, ultra-strong field

    NASA Astrophysics Data System (ADS)

    Luo, Sui

    Ultrastrong laser-matter interaction has direct bearing to next generation technologies including plasma acceleration, laser fusion and attosecond X-ray generation. The commonly known physics in strong field becomes different as one progress to ultrastrong field. The works presented in this dissertation theoretically study the influence of relativistic effect and magnetic component of the laser field on the ionization, photoelectron dynamics and elastic scattering processes. The influence of magnetic component (B laser) of circularly polarized (CP) ultrastrong fields (up to3 x 1022 W/cm2) on atomic bound state dynamics is investigated. The Poincare plots are used to find the changes in trajectory energies are on the order of a few percent for intensities up to1 x 1022 W/cm2. It is found that at intensities where ionization approaches 50% for the bound state, the small changes from Blaser of the circular polarized light can actually result in a several-fold decrease in ionization probability. The force on the bound electron exerted by the Lorentz force from B laser is perpendicular to the rotating plane of the circular polarized light, and this nature makes those trajectories which are aligned away from the minimum in the potential barrier stabilized against tunneling ionization. Our results provide a classical understanding for ionization in ultrastrong fields and indicate that relativistic effects in ultrastrong field ionization may most easily be seen with CP fields. The photoelectron energy spectra from elastic rescattering in ultrastrong laser fields (up to 2x1019 W/cm2) is studied by using a relativistic adaption of a semi-classical three-step recollision model. The Hartree-Fock scattering potentials are used in calculating the elastic rescattering for both hydrogenlike and noble gas species. It is found that there is a reduction in elastic rescattering for intensities beyond 6 x 1016 W/cm2 when the laser Lorentz deflection of the photoelectron exceeds its

  14. Neutron scattered dose equivalent to a fetus from proton radiotherapy of the mother.

    PubMed

    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

  15. Neutron scattered dose equivalent to a fetus from proton radiotherapy of the mother

    SciTech Connect

    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.

  16. Diffusive properties of water in Artemia cysts as determined from quasi-elastic neutron scattering spectra. [Artemia shrimp

    SciTech Connect

    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.

  17. Simultaneous, noninvasive observation of elastic scattering, fluorescence and inelastic scattering as a monitor of blood flow and hematocrit in human fingertip capillary beds

    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.

  18. Resonance effects in elastic cross sections for electron scattering on pyrimidine: Experiment and theory.

    PubMed

    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. PMID:26772565

  19. Resonance effects in elastic cross sections for electron scattering on pyrimidine: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D.

    2016-01-01

    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 X˜ 2A2, A˜ 2B1, and B˜ 2B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B˜ 2B1 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.

  20. 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.