WorldWideScience

Sample records for alpha particle scattering

  1. Feasibility of alpha particle measurement by CO2 laser Thomson scattering

    International Nuclear Information System (INIS)

    The feasibility of CO2 laser Thomson scattering from a multi-component burning plasma has been evaluated for the measurement of the velocity distribution of D-T produced alpha particles. The density and velocity distribution of the alpha particles from their initial energy of 3.5 MeV down to near-thermal energies may be measured by small angle (0) Thomson scattering. A computer simulation of the experiment indicates that a 100 MW pulsed laser combined with a bank of heterodyne receivers will be able to measure a scattered signal from the alpha particles with a post-detection signal-to-noise ratio of 75 for an assumed alpha density of 7.5 x 1011 cm-3

  2. Feasibility of alpha particle measurement in a magnetically confined plasma by CO2 laser Thomson scattering

    International Nuclear Information System (INIS)

    Fusion-product alpha particles will dominate the behavior of the next generation of ignited D-T fusion reactors. Advanced diagnostics will be required to characterize the energy deposition of these fast alpha particles in the magnetically confined plasma. For small-angle coherent Thomson scattering of a CO2 laser beam from such a plasma, a resonance in the scattered power occurs near 900 with respect to the magnetic field direction. This spatial concentration permits a simplified detection of the scattered laser power from the plasma using a heterodyne system. The signal produced by the presence of fusion-product alpha particles in an ignited plasma is calculated to be well above the noise level, which results from statistical variations of the background signal produced by scattering from free electrons. 7 refs

  3. Feasibility of ion temperature measurement with a gyrotron scattering alpha particle diagnostic

    International Nuclear Information System (INIS)

    Collective Thomson scattering can be used to diagnose localized ion temperature as well as alpha particle velocity distribution and density in a D-T burning tokamak. With one diagnostic beam a simultaneous, but independent, measure of the bulk ion temperature and alpha particle parameters can be made. Use of a long pulse, millimeter-wave gyrotron offers a significant margin in signal to noise ratio capability (√Δftau > 1000) not previously possible with lasers. 9 refs., 2 figs

  4. Large angle scattering of {alpha}-particles from {sup 32}S

    Energy Technology Data Exchange (ETDEWEB)

    Coban, A.; Abdelmonem, M.S.; Khiari, F.Z.; Naqvi, A.A.; Aksoy, A

    1999-01-04

    The elastic scattering of {alpha}-particles from {sup 32}S was studied in the incident energy range between 4 and 8.9 MeV. In order to ascertain whether quasi-molecular states exist, as predicted in the {alpha}-{sup 32}S system, excitation functions were measured, and angular distribution measurements were carried out using targets with different thicknesses in the angular range from {theta}{sub lab} = 30 deg. to 175 deg. at each extreme in the excitation functions. The analysis of the angular distribution data at back angles was performed using the Regge-pole method. A resonance with J=3 was observed at 7.7 MeV in the {alpha}-{sup 32}S system. Evidence was also found for both a broad resonance which can be characterized by an angular momentum J=1, and for a narrow J=2 resonance.

  5. Ab initio alpha-alpha scattering.

    Science.gov (United States)

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Luu, Thomas; Meißner, Ulf-G

    2015-12-01

    Processes such as the scattering of alpha particles ((4)He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei--nuclei with even and equal numbers of protons and neutrons--is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the 'adiabatic projection method' to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of

  6. Ab initio alpha-alpha scattering

    Science.gov (United States)

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A.; Luu, Thomas; Meißner, Ulf-G.

    2015-12-01

    Processes such as the scattering of alpha particles (4He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei—nuclei with even and equal numbers of protons and neutrons—is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the ‘adiabatic projection method’ to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of

  7. Nucleon-alpha particle interactions from inversion of scattering phase shifts

    International Nuclear Information System (INIS)

    Scattering amplitudes have been extracted from (elastic scattering) neutron-alpha (n-α) differential cross sections below threshold using the constraint that the scattering function is unitary. Real phase shifts have been obtained therefrom. A modification to the Newton iteration method has been used to solve the nonlinear equation that specifies the phase of the scattering amplitude in terms of the complete (0 to 180 deg) cross section since the condition for a unique and convergent solution by an exact iterated fixed point method, the 'Martin' condition, is not satisfied. The results compare well with those found using standard optical model search procedures. Those optical model phase shifts, from both n - α and p - α (proton-alpha) calculations in which spin-orbit effects were included, were used in the second phase of this study, namely to determine the scattering potentials by inversion of that phase shift data. A modified Newton-Sabatier scheme to solve the inverse scattering problem has been used to obtain inversion potentials (both central and spin-orbit) for nucleon energies in the range 1 to 24 MeV. The inversion interactions differ noticeably from the Woods-Saxon forms used to give the input phase shifts. Not only do those inversion potentials when used in Schroedinger equations reproduce the starting phase shifts but they are also very smooth, decay rapidly, and are as feasible as the optical model potentials of others to be the local form for interactions deduced by folding realistic two-nucleon g matrices with the density matrix elements of the alpha particle. 23 refs., 8 tabs., 9 figs

  8. Study of compound nucleus formation via bremsstrahlung emission in proton $\\alpha$-particle scattering

    CERN Document Server

    Maydanyuk, Sergei P

    2016-01-01

    In this paper a role of many-nucleon dynamics in formation of the compound $^{5}{\\rm Li}$ nucleus in the scattering of protons off $\\alpha$-particles at the proton incident energies up to 20 MeV is investigated. We propose a bremsstrahlung model allowing to extract information about probabilities of formation of such nucleus on the basis of analysis of experimental cross-sections of the bremsstrahlung photons. In order to realize this approach, the model includes elements of microscopic theory and also probabilities of formation of the short-lived compound nucleus. Results of calculations of the bremsstrahlung spectra are in good agreement with the experimental cross-sections.

  9. CO2 laser collective Thomson scattering for alpha-particle diagnostics

    International Nuclear Information System (INIS)

    In JT-60U (JAEA Tokamak 60 - Upgrade), a collective Thomson scattering (CTS) technique based on a CO2 laser is being developed in order to establish a diagnostic method of confined alpha-particles in burning plasmas. In order to the demonstrate feasibility of the CTS system, a new laser systems is being developed, with which improved signal-to-Noise (S/N) ratio of a detection signal and temporal resolution will be obtained. The laser has cavity length of ∼4 m and has high repetition rate (10 Hz). To improve the spectral purity of the laser, cavity length will be feedback-controlled and a spectral filter will be installed in the output of the laser. Numerical calculation shows that ion temperature will be evaluated from the scattered spectrum with the new CO2 laser. (author)

  10. Nuclear transparency in {alpha}-particle scattering beyond the eikonal approach

    Energy Technology Data Exchange (ETDEWEB)

    Eliseev, S.M. [Bogoliubov Laboraroty of Theoretical Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Hanna, K.M. [Matematics and Theoretical Physics Departement, AtomyEnergy Authority, Cairo (Egypt)

    1999-08-01

    An independent, complementary, and unbiased study to calculate the transparency functions beyond the eikonal approach by adding the higher-order (up to the third-order term) non eikonal (Ne) corrections, in five different effective optical potentials all of them reproduce well the elastic scattering of intermediate energy {alpha}-particles ({epsilon}{sub {alpha}} 140-288 MeV) from the two neighborly nuclei {sup 48}Ti and {sup 58}Ni. The effects of switching (off/on) the Coulomb potential on the results are studied. The individual and the combined effects of the Ne corrections and Coulomb potential are explored in the transparency function for a wide range of the impact parameter 'b' from the nuclear surface towards the nuclear interior. No violation is detected in the flux conservation for the considered projectile incident energy and the impact parameter ranges. It is found that, in some cases, it is not necessarily true, as usually believed, that the Coulomb potential decreases the absorption (less transparency) in the central region of the nucleus, the phenomenon which can be explained by a modification of the balance between the nominal real and imaginary parts of some optical potential in the rather complicate transparency function.

  11. Hauser-Feshbach cross-section calculations for elastic and inelastic scattering of alpha particles-program CORA

    International Nuclear Information System (INIS)

    The program CORA was prepared on the basis of Hauser and Feshbach compound reaction formalism. It allows the differential cross-section distributions for the elastic and inelastic scattering of alpha particles (via compound nucleus state) to be calculated. The transmission coefficients are calculated on the basis of a four parameter optical model. The search procedure is also included. (author)

  12. Diffraction scattering of alpha particles on C, Al, Cu and Pb at 17.9 GeV/c

    International Nuclear Information System (INIS)

    New data on the diffraction scattering of relativistic alpha particles on C, Al, Cu and Pb targets at incident momentum of 17.9 GeV/c are presented. Differential cross sections at four-momentum transfers squared |t| ranging from 0.038 (GeV/c)2 up to 0.55 (GeV/c)2 have been measured with an accuracy of 3% of the absolute normalization. These data are compared with the predictions of the Glauber-Sitenko multiple scattering theory. (author)

  13. New features of nuclear excitation by {alpha} particles scattering; Nouveaux aspects de l'excitation nucleaire par diffusion de particules {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Saudinos, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    Inelastic scattering of medium energy a particles by nuclei is known to excite preferentially levels of collective character. We have studied the scattering of isotopically enriched targets of Ca, Fe, Ni, Cu, Zn. In part I, we discuss the theoretical features of the interaction. In part II, we describe the experimental procedure. Results are presented and analysed in part III. {alpha} particles scattering by Ca{sup 40} is showed to excite preferentially odd parity levels. In odd nuclei we have observed multiplets due to the coupling of the odd nucleon with the even-even core vibrations. For even-even nuclei, a few levels are excited with lower cross-sections between the well-known first 2{sup +} and 3{sup -} states. Some could be members of the two phonon quadrupole excitation and involve a double nuclear excitation process. (author) [French] On sait que la diffusion inelastique des particules alpha de moyenne energie excite preferentiellement des niveaux de caractere collectif. Nous avons etudie la diffusion des particules alpha de 44 MeV du cyclotron de Saclay par des isotopes separes de Ca, Fe, Ni, Cu, Zn. Dans la premiere partie nous exposons les theories de cette interaction. Dans la seconde nous decrivons le systeme experimental. Les resultats sont donnes dans la troisieme partie. Nous montrons que les niveaux excites preferentiellement pour {sup 40}Ca par diffusion ({alpha},{alpha}') sont de parite negative. Dans les noyaux pair-impair nous avons observe des multiplets dus au couplage du nucleon celibataire avec les vibrations du coeur pair-pair. Pour les noyaux pair-pair nous avons pu etudier entre le premier niveau 2{sup +} et le niveau 3{sup -} deja bien connus certains etats plus faiblement excites. Il semble qu'ils sont dus a une excitation quadrupolaire a deux phonons et impliquent un processus de double excitation nucleaire. (auteur)

  14. Nuclear densities of 1fsub(7/2) nuclei from elastic alpha-particle scattering

    International Nuclear Information System (INIS)

    The elastic scattering of 104 MeV α particles by sup(40,42,43,44,48)Ca, 50Ti, 51V, 52Cr has been analyzed by phenomenological and semimicroscopic optical potentials in order to get information on isotopic and isotonic differences of the α particle optical potentials and of nuclear matter densities. The phenomenological optical potentials based on a Fourier-Bessel description of the real part reveal different behaviour in size and shape for the isotonic chain as compared to the isotopic chain. Odd-even effects are also indicated to be different for isotones and isotopes. The semi-microscopic analyses use a single-folding model with a density-dependent effective αN-interaction including a realistic local density approximation. The calculated potentials are fully consistent with the phenomenological ones. Isopotic and isotonic differences of the nuclear matter densities obtained from the folding model in general show a similar behavior as the optical potential differences. The results on matter densities are compared to other investigations. (orig.)

  15. Imaging alpha particle detector

    Science.gov (United States)

    Anderson, D.F.

    1980-10-29

    A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  16. Alpha-particle diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Young, K.M.

    1991-01-01

    This paper will focus on the state of development of diagnostics which are expected to provide the information needed for {alpha}- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence {alpha}-particle birth profile, (2) measurement of the escaping {alpha}-particles and (3) measurement of the confined {alpha}-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by {alpha}-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.

  17. Alpha particles in fusion research

    International Nuclear Information System (INIS)

    This collection of 39 (mostly view graph) presentations addresses various aspects of alpha particle physics in thermonuclear fusion research, including energy balance and alpha particle losses, transport, the influence of alpha particles on plasma stability, helium ash, the transition to and sustainment of a burning fusion plasma, as well as alpha particle diagnostics. Refs, figs and tabs

  18. Alpha Particle Diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Ray, K.

    2009-05-13

    The study of burning plasmas is the next frontier in fusion energy research, and will be a major objective of the U.S. fusion program through U.S. collaboration with our international partners on the ITER Project. For DT magnetic fusion to be useful for energy production, it is essential that the energetic alpha particles produced by the fusion reactions be confined long enough to deposit a significant fraction of their initial ~3.5 MeV energy in the plasma before they are lost. Development of diagnostics to study the behavior of energetic confined alpha particles is a very important if not essential part of burning plasma research. Despite the clear need for these measurements, development of diagnostics to study confined the fast confined alphas to date has proven extremely difficult, and the available techniques remain for the most part unproven and with significant uncertainties. Research under this grant had the goal of developing diagnostics of fast confined alphas, primarily based on measurements of the neutron and ion tails resulting from alpha particle knock-on collisions with the plasma deuterium and tritium fuel ions. One of the strengths of this approach is the ability to measure the alphas in the hot plasma core where the interesting ignition physics will occur.

  19. Design and calibration of a two-channel low-noise heterodyne receiver for use in a CO2 laser Thomson scattering alpha particle diagnostic

    International Nuclear Information System (INIS)

    A dual channel low noise heterodyne receiver has been constructed as part of a development effort to build a carbon dioxide laser based Thomson scattering alpha particle diagnostic for a burning plasma experiment. The receiver employs two wide bandwidth (>1 GHz) HgCdTe photovoltaic mixers followed by low noise IF amplifiers. A noise equivalent power of less than 3.0 /times/ 10-20 WHz has been demonstrated. Design details and calibration methods are described. 8 refs

  20. Application techniques of alpha particles and heavy ion elastic scattering to chemical analysis of thin layers and surfaces

    International Nuclear Information System (INIS)

    This work turns to account two aspects of the elastic scattering: Rutherford or non-Rutherford backscattering of alpha particles for the study of the stoechiometry of complex thin layers and production of recoil nuclei under energetic argon ion (16-20 MeV) bombardment for the surface analysis of light elements like oxygen, nitrogen and carbon. The first section treats the analysis conditions of Ti(1-x)NbxO2 and Ti(1-x)VxO2 layers whose composition depends on deposition parameters of the H.F. cathodic sputtering process of mixtures of oxide powders. In the first place, the analysis conditions of these layers were determined with the best possible accuracy. As for the experimental results, we show for the best deposition conditions (residual vacuum, pre-sputtering) that the ratio O/(M+Ti) can be adjusted to 2±0.1 over all the target concentration ranges. The evolution of the ratio Nb/(Nb+Ti) and V/(V+Ti) is not identical to that of targets with deviations whose significance we attempt to interprete. In the second section dealing with time of flight detection of recoil nuclei, we justify our choice of experimental parameters by a detailed study of their influence on the analytical performances. In spite of serious limitations posed by angular dispersions the depth resolution typically varies from 2 to 5 nm for oxygen and carbon depending on whether one deals with a matrix of medium Z(Si) or high Z (Ta). An energy discrimination serves at optimizing the analysable depths and avoiding interferences (C,N and O analysable over 70 nm). This discrimination allows us to lower the detection limit (down to 1013 at/cm2) by reduction of background noise. The current limitations and possible improvements are presented from surface analysis examples

  1. Optical potentials and isoscalar transition rates from 104 MeV alpha-particle scattering by the N=28 isotopes 48Ca, 50Ti and 52Cr

    International Nuclear Information System (INIS)

    Precisely measured differential cross sections for elastic and inelastic scattering from 104 MeV alpha-particles by 48Ca, 50Ti and 52Cr are reported. The analyses aim primarily at the determination of strength, radial shapes and deformation of the scattering potentials, looking for isotonic differences of N = 28 isotones. The mean square radii of the (real) potentials are discussed in terms of mean square radius differences of the matter distributions. The isoscalar transition rates derived by coupled channel analyses of the measured cross sections are compared with electromagnetic rates. In addition to the analyses on the basis of a slightly generalized extended optical model a semi-microscopic deformed folding model has been applied, using a density-dependent effective alpha-bound nucleon interaction. Though an excellent description of the data over the full angular range is obtained the resulting values of the deformation parameters appear to be not consistent with results from various different methods. (orig.)

  2. ITER Plasma at Ion Cyclotron Frequency Domain: The Fusion Alpha Particles Diagnostics Based on the Stimulated Raman Scattering of Fast Magnetosonic Wave off High Harmonic Ion Bernstein Modes

    Science.gov (United States)

    Stefan, V. Alexander

    2014-10-01

    A novel method for alpha particle diagnostics is proposed. The theory of stimulated Raman scattering, SRS, of the fast wave and ion Bernstein mode, IBM, turbulence in multi-ion species plasmas, (Stefan University Press, La Jolla, CA, 2008). is utilized for the diagnostics of fast ions, (4)He (+2), in ITER plasmas. Nonlinear Landau damping of the IBM on fast ions near the plasma edge leads to the space-time changes in the turbulence level, (inverse alpha particle channeling). The space-time monitoring of the IBM turbulence via the SRS techniques may prove efficient for the real time study of the fast ion velocity distribution function, spatial distribution, and transport. Supported by Nikola Tesla Labs., La Jolla, CA 92037.

  3. Strong absorption model analysis of alpha scattering

    International Nuclear Information System (INIS)

    Angular distribution of alpha-particles at several energies, Eα = 21 ∼ 85.6 MeV from a number of nuclei between 20Ni and 119Sn, extending to wide angular range up to ∼ 160 deg. C in some cases, have been analyzed in terms of three-parameter strong absorption model of Frahn and Venter. Interaction radius and surface diffuseness are obtained from the parameter values rendering the best fit to the elastic scattering data. The inelastic scattering of alpha-particles from a number of nuclei, leading to quadrupole and octupole excitations has also been studied giving the deformation parameters βL. (author). 14 refs, 7 figs, 3 tabs

  4. Attempt of analysis of the elastic scattering of 44 MeV alpha particles using a phase shift parameterization

    International Nuclear Information System (INIS)

    In order to ease the resolution of the problem of interaction of an alpha particle with a nucleus, and determine simpler hypotheses which enable the analysis of experimental results, this research thesis reports the use of a parameterization of phase shifts to reduce ambiguities and the number of parameters. After general remarks, a description of the Hamiltonian and a formulation of phase shifts, the author presents experimental data and the analytical method. Analysis is then performed for two-, three-, four- or five-parameter formulations. Efficient cross sections are then studied

  5. Collective relaxation, single particle motion and short range order in. cap alpha. '-NbD/sub x/: A quasielastic neutron scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Hempelmann, R.; Richter, D.; Faux, D.A.; Ross, D.K.

    1988-01-01

    Applying both incoherent and coherent quasielastic neutron scattering we have studied simultaneously single particle motion, collective relaxation and short range order of deuterium in ..cap alpha..'-NbD/sub x/. A comparison with recent Monte Carlo simulations lead to a consistent description of all results in terms of strongly repulsive deuterium-deuterium interactions. Relating the independently determined tracer and chemical diffusion coefficients with the also measured structure factor we show experimentally that for lattice gases the de Gennes narrowing Ansatz needs to be modified by correlation factors. 18 refs., 3 figs., 1 tab.

  6. Backangle anomaly in scattering of {alpha} -particles from {sup 28} Si at low energies[25.55.Ci; 25.70.Ef; Nuclear reactions 28 Si( {alpha},{alpha})28 Si; E{alpha}=3.0 -7.8 MeV; Measured {sigma}(E{alpha},{theta}); {theta}lab=30 deg. -175 deg.; Deduced Regge-pole parameters; Natural target

    Energy Technology Data Exchange (ETDEWEB)

    Coban, A.; Khiari, F.Z.; Abdelmonem, M.S.; Aksoy, A.; Naqvi, A.A

    2000-09-25

    In order to resolve the differences in the literature on the existence of quasi-molecular states in the {alpha} -{sup 28} Si system, excitation functions were measured for the scattering of {alpha} -particles from {sup 28} Si in the incident energy range E{sub lab}=3 -7.8 MeV. An angular distribution measurement was carried out in the angular range {theta}{sub lab}=30 deg. -174.5 deg. for every potential resonance observed in the excitation functions. Data was analysed using a Regge-pole formalism by coherently adding specific resonances to an underlying diffraction term calculated by a strong absorption model. Furthermore, the usual compound elastic contribution was incoherently added to the direct interaction part of the cross section. The 6.8 MeV resonance was confirmed with J=3 and some evidence was observed for a J=1 resonance around 6.0 MeV.

  7. Investigations of the radial distributions of nucleons in 1fsub(7/2)-shell nuclei by elastic alpha particle scattering

    International Nuclear Information System (INIS)

    The radial size and shape of the distribution of nucleons - i.e. the sum of protons and neutrons - in atomic nuclei of the 1fsub(7/2) shell is investigated in the present work. The experimental basis of the studies are differential cross sections of elastic α particle scattering by sup(40,42,43,44,48)Ca, 50Ti, 51V, 52Cr precisely measured over a wide angular range at the 104 MeV α particle beam from the Karlsruhe Isochronous Cyclotron. The experimental cross sections are analyzed using so-called 'model independent' optical potentials by which the data are very well reproduced. The error bands of these potentials are determined in a well-defined form from the analyses. The high sensitivity of the data to the radial form of the real optical potential justifies, in principle, that the experiments are a suitable tool for investigating nuclear density distributions. Some pre-informations on this question are obtained from the optical potential analyses. For a more direct access to the nuclear matter distributions - in particular to differences between neighbouring nuclei - a semimicroscopic reaction model is presented which on the one hand is based on a fully microscopic many body approach. On the other hand all quantities being not of particular interest for the results are treated in a phenomenological way. Thereby, it is possible to reproduce the experimental cross sections as well as by the 'model independent' potentials and to obtain full consistency between the two approaches. This has not been achieved by any other microscopic reaction model. (orig./HSI)

  8. Alpha Particle Emission in Fission

    International Nuclear Information System (INIS)

    Soon after it was discovered that alpha particles are occasionally emitted in fission, it was concluded, on the basis of the energy and angular distributions of these particles, that they are emitted from the space between the fragments at times close to that of the snapping of the neck that connects them. It is shown that, independent of any (still unknown) dynamic features of the alpha-particle ejection process, the energy required to emit alpha particles from between the fragments at the indicated time is barely available. Presumably the rareness of alpha particles in fission, and the apparent absence of still heavier ''third'' particles, is associated with the marginal energy supply at the time of actual fragment division. The fact that the total kinetic energy release in so-called ternary fission is roughly equal to that in normal binary fission instead of being about 20 MeV larger is shown to imply that the mean fragment separation at the division time is larger in ternary fission. This is interpreted to indicate that alpha particles are emitted with greatest probability n those fissions where ample energy happens to be provided through the stretching of an abnormally long neck between the fragments before they actually divide. It is suggested that the release of the alpha particles is a sudden rather than adiabatic process. (author)

  9. Alpha particle physics for ITER

    International Nuclear Information System (INIS)

    The paper is devoted to the analysis of a variety of physical processes which, in the ITER EDA configuration, determine the nature of alpha particle heating in the plasma interior and alpha particle losses to the first wall. The paper consists of results from the alpha particle toroidal field (TF) ripple loss calculations and an analysis of alpha particle collective effects including Alfven modes, sawtooth stabilization, etc. It is shown that the ripple loss in the present ITER configuration is only a few per cent, which cannot directly affect the achievement of ignition. In spite of the up-down asymmetry, the loss fraction does not strongly depend on the toroidal drift direction. However, the heat load is highly localized and can be as high as 1 MW/m2 on the top of the protective limiters. Preliminary calculations of toroidicity induced Alfven eigenmode (TAE) stability indicate that high n numbers may be unstable, but the computational tools, needed for reliable quantitative predictions, are still in a state of development. The likelihood of appreciable alpha particle loss will depend on whether TAE modes produce stochastic alpha particle diffusion or not. The effect of fast particles on the m = 1 mode is also discussed. (author). 15 refs, 2 figs, 1 tab

  10. Alpha particle emitters in medicine

    International Nuclear Information System (INIS)

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 (211At) and natural bismuth-212 (212Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 (223Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs

  11. Light scattering by cosmic particles

    OpenAIRE

    Hovenier, J.W.; Min, M.

    2008-01-01

    We define cosmic particles as particles outside the Earth. Two types of cosmic particles can be distinguished, namely liquid and solid particles. The solid particles are often called grains or cosmic dust particles. Cosmic particles occur in a great variety of astronomical objects and environments. At light scattering conferences most attention is usually paid to Solar System bodies. The main purpose of this contribution is to provide a brief introduction to light scattering by cosmic particl...

  12. Refinement of the Compton-Rayleigh scatter ratio method for use on the Mars Science Laboratory alpha particle X-ray spectrometer: II - Extraction of invisible element content

    Science.gov (United States)

    Perrett, Glynis M.; Campbell, John L.; Gellert, Ralf; King, Penelope L.; Nield, Emily; O'Meara, Joanne M.; Pradler, Irina

    2016-02-01

    The intensity ratio C/R between Compton and Rayleigh scatter peaks of the exciting Pu L X-rays in the alpha particle X-ray spectrometer (APXS) is strongly affected by the presence of very light elements such as oxygen which cannot be detected directly by the APXS. C/R values are determined along with element concentrations by fitting APXS spectra of geochemical reference materials (GRMs) with the GUAPX code. A quantity K is defined as the ratio between the C/R value determined by Monte Carlo simulation based on the measured element concentrations and the fitted C/R value from the spectrum. To ensure optimally accurate K values, the choice of appropriate GRMs is explored in detail, with attention paid to Rb and Sr, whose characteristic Kα X-ray peaks overlap the Pu Lα scatter peaks. The resulting relationship between the ratio K and the overall oxygen fraction is linear. This provides a calibration from which the concentration of additional light invisible constituents (ALICs) such as water may be estimated in unknown rock and conglomerate samples. Several GRMs are used as 'unknowns' in order to evaluate the accuracy of ALIC concentrations derived in this manner.

  13. Refinement of the Compton–Rayleigh scatter ratio method for use on the Mars Science Laboratory alpha particle X-ray spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.L., E-mail: icampbel@uoguelph.ca [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Perrett, G.M. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Maxwell, J.A. [3A 47 Surrey St. East, Guelph, Ontario, Canada N1H 3P6 (Canada); Nield, E.; Gellert, R. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); King, P.L. [Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 (Australia); Lee, M.; O’Meara, J.M.; Pradler, I. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada)

    2013-05-01

    Spectra from the Mars rover alpha particle X-ray spectrometers contain the elastic and inelastic scatter peaks of the plutonium L X-rays emitted by the instrument’s {sup 244}Cm source. Various spectrum fitting approaches are tested using the terrestrial twin of the APXS instrument on the Mars Science Laboratory Curiosity rover, in order to provide accurate extraction of the Lα and Lβ Compton/Rayleigh intensity ratios, which can provide information about light “invisible” constituents such as water in geological samples. A well-defined dependence of C/R ratios upon mean sample atomic number is established using a large and varied set of geochemical reference materials, and the accuracy of this calibration is examined. Detailed attention is paid to the influence of the rubidium and strontium peaks which overlap the Lα scatter peaks. Our Monte Carlo simulation code for prediction of C/R ratios from element concentrations is updated. The ratio between measured and simulated C/R ratios provides a second means of calibration.

  14. Alpha-particle diagnostics

    International Nuclear Information System (INIS)

    This paper will focus on the state of development of diagnostics which are expected to provide the information needed for α- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence α-particle birth profile, (2) measurement of the escaping α-particles and (3) measurement of the confined α-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by α-particles and the methods necessary for measuring these effects. 51 refs., 10 figs

  15. Study by {alpha}-particle scattering, of the collective states of closed shell nuclei with 28 neutrons, 28 and 50 protons; Etude des etats a caractere collectif des noyaux au voisinage des couches fermees par diffusion inelastique des particules {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Bruge, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-01-01

    This report gives the results from a systematic study by 44 MeV {alpha} particle scattering on the collective states of closed shell nuclei with 28 neutrons, 28 and 50 protons especially in the energy region corresponding to the two phonon vibrational triplet. The nuclei studied are: {sup 46}Ti, {sup 48}Ti, {sup 50}Ti, {sup 52}Cr, {sup 54}Fe, {sup 56}Fe, {sup 58}Fe, {sup 58}Ni, {sup 60}Ni, {sup 62}Ni, {sup 64}Ni, {sup 112}Sn, {sup 114}Sn, {sup 116}Sn, {sup 118}Sn, {sup 120}Sn, {sup 122}Sn and {sup 124}Sn. The theoretical analysis has been made with the Austern and Blair model using a phase shift analysis of the elastic scattering. Deformation lengths {delta}{sub I} = {beta}{sub I}R and transition probabilities obtained are compared with several experimental and theoretical data. (author) [French] Ce rapport donne les resultats d'une etude systematique par diffusion de particules {alpha} de 44 MeV des etats collectifs des noyaux au voisinage des couches fermees a 28 neutrons et 28 et 50 protons, specialement dans la region correspondant au triplet vibrationnel a deux phonons. Les noyaux etudies sont: {sup 46}Ti, {sup 48}Ti, {sup 50}Ti, {sup 52}Cr, {sup 54}Fe, {sup 56}Fe, {sup 58}Fe, {sup 58}Ni, {sup 60}Ni, {sup 62}Ni, {sup 64}Ni, {sup 112}Sn, {sup 114}Sn, {sup 116}Sn, {sup 118}Sn, {sup 120}Sn, {sup 122}Sn et {sup 124}Sn. L'analyse theorique a ete faite a l'aide du modele de Austern et Blair utilisant une analyse en dephasages de la diffusion elastique. Les longueurs de deformation {delta}I = {beta}{sub I}R obtenues pour chaque niveau sont comparees a plusieurs donnees experimentales et theoriques. (auteur)

  16. The alpha-particle structure of 44 Ti

    International Nuclear Information System (INIS)

    Some of the bound and unbound states of 44 Ti have a pronounced alpha-particle structure, and their energies and widths may be obtained from an alpha 40 Ca potential. The differential cross-sections for the elastic scattering of alpha particles by 40 a may also be described by such a potential, and some features indicate the presence of unbound states of 44 Ti. The attempts to unify these bound and scattering phenomena by the same potential are described, together with some new calculations using a cosh potential. (author)

  17. Nanodosimetry of radon alpha particles

    International Nuclear Information System (INIS)

    It is currently accepted that energy deposition at the nanometer level (rather than conventional microdosimetry) determines the biological effects of ionizing radiation. Many previously established experimental techniques (e.g., the Rossi proportional counter) or theoretical methods (e.g., simplified calculations using the continuous slowing-down approximation (CSDA)) are inapplicable to the study of nanodosimetry. The peculiarities of the geometry of exposure to radon progeny further complicate the problem. This is because the conditions under which several open-quotes classicalclose quotes models of radiation action are obtained (e.g., the alpha-beta formulation of the Theory of Dual Radiation Action, which is built on microdosimetry) are no longer valid. It thus becomes clear that not only new techniques but new concepts are required to describe the effects of radon alpha particles. In this paper we discuss a number of computational aspects specific to radon nanodosimetry. In particular, we describe the novel concept of open-quotes associated surfaceclose quotes (AS) which is necessary for efficiently converting Monte-Carlo-generated particle tracks to nanodosimetric spectra. The AS is the analog of Lea's associated volume, applied to radiation sources subject to the geometrical restrictions of internal exposure. We systematically analyze factors affecting the nanodosimetry of radon progeny, such as the distance between the radioactive source and the sensitive volume, the size of the sensitive volume, and CSDA versus full Monte-Carlo track generation

  18. Nanodosimetry of radon alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Zaider, M. [Columbia Univ. New York, NY (United States); Varma, M.N. [U.S. Department of Energy, Washington, DC (United States)

    1992-12-31

    It is currently accepted that energy deposition at the nanometer level (rather than conventional microdosimetry) determines the biological effects of ionizing radiation. Many previously established experimental techniques (e.g., the Rossi proportional counter) or theoretical methods (e.g., simplified calculations using the continuous slowing-down approximation (CSDA)) are inapplicable to the study of nanodosimetry. The peculiarities of the geometry of exposure to radon progeny further complicate the problem. This is because the conditions under which several {open_quotes}classical{close_quotes} models of radiation action are obtained (e.g., the alpha-beta formulation of the Theory of Dual Radiation Action, which is built on microdosimetry) are no longer valid. It thus becomes clear that not only new techniques but new concepts are required to describe the effects of radon alpha particles. In this paper we discuss a number of computational aspects specific to radon nanodosimetry. In particular, we describe the novel concept of {open_quotes}associated surface{close_quotes} (AS) which is necessary for efficiently converting Monte-Carlo-generated particle tracks to nanodosimetric spectra. The AS is the analog of Lea`s associated volume, applied to radiation sources subject to the geometrical restrictions of internal exposure. We systematically analyze factors affecting the nanodosimetry of radon progeny, such as the distance between the radioactive source and the sensitive volume, the size of the sensitive volume, and CSDA versus full Monte-Carlo track generation.

  19. Light scattering by small particles

    CERN Document Server

    Hulst, H C van de

    1981-01-01

    ""A must for researchers using the techniques of light scattering."" ? S. C. Snowdon, Journal of the Franklin InstituteThe measurement of light scattering of independent, homogeneous particles has many useful applications in physical chemistry, meteorology and astronomy. There is, however, a sizeable gap between the abstract formulae related to electromagnetic-wave-scattering phenomena, and the computation of reliable figures and curves. Dr. van de Hulst's book enables researchers to bridge that gap. The product of twelve years of work, it is an exhaustive study of light-scattering properties

  20. Study of the nuclear matter distribution and isoscalar transition rates of 48Ca, 50Ti and 52Cr by scattering of 104 MeV alpha-particles

    International Nuclear Information System (INIS)

    The differential cross-sections for elastic and inelastic scattering of 104 MeV α-particles on 50Ti and 52Cr have been measured for scattering angles in the range 20 0. Additionally using previously measured data for 48Ca, the cross-sections of the N = 28 isotopic sequence 48Ca-50Ti-52Cr were analyzed on the basis of the generalized optical model. Study of the angular distribution of the elastic scattering, using modified phenomenological and microscopic methods, leads to well defined and consistent values for moments of the potentials and of the matter distributions. In particular, the Fourier-Bessel method leads to a nearly model-independent determination of the differences in isotonic radii and also to a realistic determination of error bars. For the analysis of the inelastic scattering a new method is introduced, which strongly reduces the model dependence which arises when simple analytic expressions are used for the form factors (the form of the coupling potentials). For this purpose the Fourier-Bessel method has been extended to the analysis of inelastic scattering using the collective vibrational model. Using the identities between the integral moments of a folded potential and of the underlying nuclear matter distribution, isoscalar transition rates have been derived. The extracted values are confirmed by an explicit folding model analysis. Furthermore, the folding model calculations show that the density dependence of the effective interaction between α-particle and target nucleons must be taken into account also in the analysis of inelastic scattering. (orig.)

  1. Alpha particle problems in shielded support systems

    International Nuclear Information System (INIS)

    Alpha particle confinement is considered in the case of internal conductor systems with magnetically shielded supports. The treatment includes problems of energy transfer to the background plasma, the balance between radiation losses and alpha particle heating, mirror confinement in the main poloidal field, the cut-off and shielding conditions at the supports, ambipolar electric fields, wall interaction, and support location. With a proper and technically realizable choice of parameter values, it should become possible to achieve alpha particle heating as well as to manage the reactor technological problems due to alpha particle interaction with the supports. (Auth.)

  2. Prospects for alpha particle studies on TFTR

    International Nuclear Information System (INIS)

    TFTR is expected to produce approximately 5 MW of alpha heating during the D/T Q ≅ 1 phase of operation in 1990. At that point the collective confinement properties and the heating effects of alpha particles become accessible for study for the first time. This paper outlines the potential performance of TFTR with respect to alpha particle production, the diagnostics which will be available for alpha particle measurements, and the physics issues which can be studied both before and during D/T operation

  3. Dynamical Screening Effect on $\\alpha$-$\\alpha$ Resonant Scattering and Thermal Nuclear Scattering Rate

    CERN Document Server

    Yao, Xiaojun; Müller, Berndt

    2016-01-01

    We study the dynamical screening effect in the QED plasma on the $\\alpha$-$\\alpha$ scattering at the $^8$Be resonance. Dynamical screening leads to an imaginary part of the potential which results in a thermal width for the resonance and dominates over the previously considered static screening effect. As a result, both the resonance energy and width increase with the plasma temperature. Furthermore, dynamical screening can have a huge impact on the $\\alpha$-$\\alpha$ thermal nuclear scattering rate. For example, when the temperature is around $10$ keV, the rate is suppressed by a factor of about $900$. We expect similar thermal suppressions of nuclear reaction rates to occur in nuclear reactions dominated by an above threshold resonance with a thermal energy. Dynamical screening effects on nuclear reactions can be relevant to cosmology and astrophysics.

  4. Elastic scattering of 104 MeV alpha particles from 40,42,44,48Ca and determination of the optical potentials

    International Nuclear Information System (INIS)

    Differential cross sections for elastic scattering of 104 MeV α particles from 40,42,44,48Ca have been measured with high angular accuracy over a wide angular range. Optical model analyses using different approaches for the potential form including a Fourier-Bessel description of the real potential reveal isotopic differences which, in particular for 48Ca, indicate a small neutron skin. The model dependence of the extracted quantities is discussed in detail. (orig.) 891 KBE/orig. 892 BRE

  5. Alpha particle confinement in tandem mirrors

    International Nuclear Information System (INIS)

    Mechanisms leading to loss of alpha particles from non-axisymmetric tandem mirrors are considered. Stochastic diffusion due to bounce-drift resonances, which can cause rapid radial losses of high-energy alpha particles, can be suppressed by imposing a 20% rise in axisymmetric fields before the quadrupole transition sections. Alpha particles should then be well-confined until thermal energies when they enter the resonant plateau require. A fast code for computation of drift behavior in reactors is described. Sample calculations are presented for resonant particles in a proposed coil set for the Tandem Mirror Next Step

  6. Observation of Airy minimum in elastic and inelastic scattering of $^3$He from $^{12}$C at 50.5 and 60 MeV and alpha particle condensation in $^{12}$C

    CERN Document Server

    Hamada, Sh; Burtebayev, N; Ohkubo, S

    2013-01-01

    Angular distributions for elastic and inelastic scattering of $^3$He from $^{12}$C were measured at energies 50.5 and 60 MeV. The Airy minimum of the prerainbow scattering was clearly observed in the angular distributions for the 0$_2^+$ (7.65 MeV) state of $^{12}$C (Hoyle state). The experimental results were analyzed with a coupled channels method with double folding potentials derived from the microscopic wave functions for the ground 0$_1^+$, 2$^+$ (4.44 MeV), 3$^-$ (9.64 MeV) and 0$_2^+$ states. The analysis supports the view that the Hoyle state is a three alpha particle condensate with a large radius of dilute matter distribution.

  7. Entanglement Entropy of Scattering Particles

    CERN Document Server

    Peschanski, Robi

    2016-01-01

    We study the entanglement entropy between the two outgoing particles in an elastic scattering process. It is formulated within an S-matrix formalism using the partial wave expansion of two-body states, which plays a significant role in our computation. As a result, we obtain a novel formula that describes the entanglement entropy in a high energy scattering by the use of physical observables, namely the elastic and total cross sections and a physical bound on the impact parameter range, related to the elastic differential cross-section.

  8. Entanglement entropy of scattering particles

    Science.gov (United States)

    Peschanski, Robi; Seki, Shigenori

    2016-07-01

    We study the entanglement entropy between the two outgoing particles in an elastic scattering process. It is formulated within an S-matrix formalism using the partial wave expansion of two-body states, which plays a significant role in our computation. As a result, we obtain a novel formula that expresses the entanglement entropy in a high energy scattering by the use of physical observables, namely the elastic and total cross sections and a physical bound on the impact parameter range, related to the elastic differential cross-section.

  9. High resolution alpha particle spectrometry through collimation

    International Nuclear Information System (INIS)

    Alpha particle spectrometry with collimation is a useful method for identifying nuclear materials among various nuclides. A mesh type collimator reduces the low energy tail and broadened energy distribution by cutting off particles with a low incidence angle. The relation between the resolution and the counting efficiency can be investigated by changing a ratio of the mesh hole diameter and the collimator thickness. Through collimation, a target particle can be distinguished by a PIPS® detector under a mixture of various nuclides. - Highlights: • Alpha particle spectrometry with collimation a useful method for identifying nuclear materials among various radionuclides. • A collimator cut off alpha particles with low angle emitted from a source. • We confirm that that a collimator improves the resolution of alpha spectra through both simulation and experiments

  10. Alpha emitters in Chernobyl hot particles

    International Nuclear Information System (INIS)

    The alpha radioactive component of hot particles from the Chernobyl fallout was analysed for cases studied previously by gamma spectroscopy. Correlations established from the absolute alpha activity determination and high resolution analysis provided information on actinides release during accident and on some aspects of the Chernobyl reactor fuel composition. Unexpected features revealed during the analysis of one specific particle are presented. 11 refs., 5 figs., 5 tabs. (author)

  11. Alpha emitters in Chernobyl hot particles

    Energy Technology Data Exchange (ETDEWEB)

    Broda, R.; Kubica, B.; Szeglowski, Z.; Zuber, K. (Institute of Nuclear Physics, Krakow (Poland))

    1989-01-01

    The alpha radioactive component of hot particles from the Chernobyl fallout was analyzed for cases studied previously by gamma spectroscopy. Correlations established from the absolute alpha activity determination and high resolution analysis provided information on the release of actinides during the accident and on some aspects of the Chernobyl reactor fuel composition. Unexpected features revealed during the analysis of one specific particle are presented. (orig.).

  12. Alpha particles detection in nitrocellulose

    International Nuclear Information System (INIS)

    The method for the manufacturing of the detection films follows these steps: preparation of the mass which includes nitrocellulose in the form of cotton as raw material ethyl acetate, cellosolve acetate, isopropyl and butyl alcohols as solvents and dioctyl phtalate as plasticiser; dilution of the paste; pouring of the diluted mass; and drying of the detection films. The results obtained experimentally are: The determination of the development times of the different thicknesses of the manufactured films. Response linearity of the detectors, variation of the number of tracks according to the distance of the source to the detector. Sizes of the diameter of the tracks depending of the distance detector-alpha emmission source. As a conclusion we can say the the nitrocellulose detectors are specific for alpha radiation; the more effective thicknesses in uranium prospecting works were those of 60 microns, since for the laboratory works the thicknesses of 30 to 40 microns were the ideal; the development technique of the detection films is simple and cheap and can be realized even in another place than the laboratory; this way of the manufacturing of nitrocellulose detection film sensitive to alpha nuclear radiation is open to future research. (author)

  13. Quantum Monte Carlo calculations of neutron-alpha scattering

    OpenAIRE

    Nollett, Kenneth M.; Pieper, Steven C.; Wiringa, R. B.; Carlson, J; Hale, G M

    2006-01-01

    We describe a new method to treat low-energy scattering problems in few-nucleon systems, and we apply it to the five-body case of neutron-alpha scattering. The method allows precise calculations of low-lying resonances and their widths. We find that a good three-nucleon interaction is crucial to obtain an accurate description of neutron-alpha scattering.

  14. Alpha particles spectrometer with photodiode PIN

    International Nuclear Information System (INIS)

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  15. Alpha particle spectroscopy by gridded ionization chamber

    International Nuclear Information System (INIS)

    A gridded ionization chamber has been constructed with the aim of determining its ultimate energy resolution in alpha spectroscopy, utilizing a cooled FET pre-amplifier of the type normally employed with semiconductor detectors. With suitable mechanical collimation of the alpha particles, their fine structure has been measured with an energy resolution of -11.5 keV (fwhm), achieved using an Ar + 0.75% C2H2 mixture as the filling gas. (orig.)

  16. Reviews Book: Marie Curie and Her Daughters Resource: Cumulus Equipment: Alpha Particle Scattering Apparatus Equipment: 3D Magnetic Tube Equipment: National Grid Transmission Model Book: Einstein's Physics Equipment: Barton's Pendulums Equipment: Weather Station Web Watch

    Science.gov (United States)

    2013-09-01

    WE RECOMMEND Marie Curie and Her Daughters An insightful study of a resilient and ingenious family and their achievements Cumulus Simple to install and operate and with obvious teaching applications, this weather station 'donationware' is as easy to recommend as it is to use Alpha Particle Scattering Apparatus Good design and construction make for good results National Grid Transmission Model Despite its expense, this resource offers excellent value Einstein's Physics A vivid, accurate, compelling and rigorous treatment, but requiring an investment of time and thought WORTH A LOOK 3D Magnetic Tube Magnetic fields in three dimensions at a low cost Barton's Pendulums A neat, well-made and handy variant, but not a replacement for the more traditional version Weather Station Though not as robust or substantial as hoped for, this can be put to good use with the right software WEB WATCH An online experiment and worksheet are useful for teaching motor efficiency, a glance at CERN, and NASA's interesting information on the alpha-magnetic spectrometer and climate change

  17. Folding model study of the elastic $\\alpha + \\alpha$ scattering at low energies

    CERN Document Server

    Tan, Ngo Hai; Khoa, Dao T

    2014-01-01

    The folding model analysis of the elastic $\\alpha + \\alpha$ scattering at the incident energies below the reaction threshold of 34.7 MeV (in the lab system) has been done using the well-tested density dependent versions of the M3Y interaction and realistic choices for the $^4$He density. Because the absorption is negligible at the energies below the reaction threshold, we were able to probe the $\\alpha + \\alpha$ optical potential at low energies quite unambiguously and found that the $\\alpha + \\alpha$ overlap density used to construct the density dependence of the M3Y interaction is strongly distorted by the Pauli blocking. This result gives possible explanation of a long-standing inconsistency of the double-folding model in its study of the elastic $\\alpha + \\alpha$ and $\\alpha$-nucleus scattering at low energies using the same realistic density dependent M3Y interaction.

  18. Alpha particles diffusion due to charge changes

    Energy Technology Data Exchange (ETDEWEB)

    Clauser, C. F., E-mail: cesar.clauser@ib.edu.ar; Farengo, R. [Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica and Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 Bariloche (Argentina)

    2015-12-15

    Alpha particles diffusion due to charge changes in a magnetized plasma is studied. Analytical calculations and numerical simulations are employed to show that this process can be very important in the pedestal-edge-SOL regions. This is the first study that presents clear evidence of the importance of atomic processes on the diffusion of alpha particles. A simple 1D model that includes inelastic collisions with plasma species, “cold” neutrals, and partially ionized species was employed. The code, which follows the exact particle orbits and includes the effect of inelastic collisions via a Monte Carlo type random process, runs on a graphic processor unit (GPU). The analytical and numerical results show excellent agreement when a uniform background (plasma and cold species) is assumed. The simulations also show that the gradients in the density of the plasma and cold species, which are large and opposite in the edge region, produce an inward flux of alpha particles. Calculations of the alpha particles flux reaching the walls or divertor plates should include these processes.

  19. Alpha particle effects on MHD ballooning

    International Nuclear Information System (INIS)

    During the period, as the first step towards the goal of detail understanding of the effects of alpha particle on MHD Ballooning Modes, a new numerical approach to investigate the stability of low-frequency fluctuations in high temperature tokamaks was developed by solving the gyrokinetic equations for the ion and electron directly as an initial value problem. The advantage of this approach is the inclusion of many important kinetic features of the problem without approximations and computationally more economical than particle-pushing simulation. The ion-temperature-gradient-mode was investigated to benchmark this new simulation technique. Previous results in literature were recovered. Both the adiabatic electron model and the full drift-kinetic electron model are studied. Numerical result shows that the full drift-kinetic electron model is more unstable. The development of subcycling technique to handle the fast electron bounce time is particularly significant to apply this new approach to the alpha particle problem since alpha particle bounce frequency is also significantly higher than the mode frequency. This new numerical technique will be the basis of future study of the microstability in high temperature tokamaks with alpha particles (or any energetic species). 15 refs., 13 figs

  20. Alpha particles energy straggling in noble gases

    International Nuclear Information System (INIS)

    The comparison of the calculated spectra by the Monte-Carlo simulation with the experimental alpha-particles spectra after their passage through noble gases target has good agreement for Ar, Kr, and Xe and significant deviation for He and Ne. These agreement or disagreement of the calculated and experimental spectra were ascribed to adequacy or inadequacy of the applied Bohr's charged particles energy loss formula for the specific medium. (author)

  1. Soft particle production in deep inelastic scattering

    International Nuclear Information System (INIS)

    Results on the analysis of the hadronic final state in neutral current deep inelastic scattering at HERA are presented; recent results on inclusive single particle distributions, particle correlations and event shapes are highlighted. (author)

  2. Superparamagnetic relaxation in alpha-Fe particles

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen; Pedersen, Michael Stanley; Svedlindh, P.; Jonsson, G.T.; Garcia-Palacios, J.L.; Lazaro, F.J.

    1998-01-01

    The superparamagnetic relaxation time of carbon-supported alpha-Fe particles with an average size of 3.0 Mm has been studied over a large temperature range by the use of Mossbauer spectroscopy combined with AC and DC magnetization measurements. It is found that the relaxation time varies with...

  3. Particle scattering applications in solar panels

    Science.gov (United States)

    Seneviratne, Jehan; Berg, Matthew

    2014-03-01

    The focus of this work is to apply the scattering characteristics of particles to model particle assisted solar concentrators. In this work, the scattering patterns of particles of different shapes, sizes, and refractive indices are computationally studied using Discrete Dipole Approximation (DDA). The study investigates the optical behavior of different particle ensembles. The simulated results are used to explain the characteristic behavior seen in. The computational methodology can be used to determine the ideal ensemble of particles to produce the most efficient energy yield in a scattering-based photovoltaic concentrator.

  4. Alpha-particle losses in compact torsatron reactors

    International Nuclear Information System (INIS)

    Loss of alpha particles in compact torsatron reactors is studied. For 6, 9, and 12 field period reactors, the direct loss is a relatively weak function of radius and energy and varies from ≅33% for M = 6 to ≅18% for M = 12. Loss of alpha particles through scattering into the loss region is calculated using the Fokker-Plank equation for fast ions and found to contribute an additional alpha-particle energy loss of ≅15%. The consequences of these relatively large losses for torsatron reactor design are discussed. The relationship between the direct particle losses and the magnetic field structure is also studied. Orbit losses from a variety of stellarator configurations are calculated and a figure-of-merit that characterizes the orbit confinement of a magnetic configuration is deduced from these calculations. This figure-of-merit is used to show how the direct losses might be reduced at low aspect-ratio. Effects of finite beta on the direct particle losses are also addressed, and are shown to significantly increase the direct losses in some configurations. 15 refs., 8 figs

  5. A practical alpha particle irradiator for studying internal alpha particle exposure.

    Science.gov (United States)

    Lee, Ki-Man; Lee, Ui-Seob; Kim, Eun-Hee

    2016-09-01

    An alpha particle irradiator has been built in the Radiation Bioengineering Laboratory at Seoul National University (SNU) to investigate the cellular responses to alpha emissions from radon and the progeny. This irradiator is designed to have the energy of alpha particles entering target cells similar to that of alpha emissions from the radon progeny Po-218 and Po-214 residing in the human respiratory tract. For the SNU alpha particle irradiator, an irradiation system is equipped with cell dishes of 4µm thick Mylar bottom and a special setup of cells on slide for gamma-H2AX assay. Dose calibration for the alpha particle irradiator was performed by dual approaches, detection and computer simulation, in consideration of the source-to-target distance (STD) and the size of a cell dish. The uniformity of dose among cells in a dish is achieved by keeping the STD and the size of cell dish in certain ranges. The performance of the SNU alpha particle irradiator has been proven to be reliable through the gamma-H2AX assay with the human lung epithelial cells irradiated. PMID:27475622

  6. Microscopic study of the isoscalar excitations by the alpha inelastic scattering

    International Nuclear Information System (INIS)

    Alpha particle with zero spin and isospin is a very good projectile to study isoscalar excited states by direct reaction. We have performed analyzing the alpha inelastic scattering on stable targets 12C and 208Pb to discuss about characteristics of isoscalar excitation. The feature of 0+2 state in 12C was presented. Otherwise, the existence of 2+2 state in 12C was discussed more detail. The isoscalar strength distribution in 208Pb was showed. (author)

  7. Alpha particle diagnostics using impurity pellet injection

    International Nuclear Information System (INIS)

    We have proposed using impurity injection to measure the energy distribution of the fast confined alpha particles in a reacting plasma. The ablation cloud surrounding the injected pellet is thick enough that an equilibrium fraction Fo∞(E) of the incident alphas should be neutralized as they pass through the cloud. By observing neutrals created in the large spatial region of the cloud which is expected to be dominated by the helium-like ionization state, e.g., Li+ ions, we can determine the incident alpha distribution dnHe2+/dE from the measured energy distribution of neutral helium atoms. Initial experiments were performed on TEXT in which we compared pellet penetration with our impurity pellet ablation model, and measured the spatial distribution of various ionization states in carbon pellet clouds. Experiments have recently begun on TFTR with the goal of measuring the alpha particle energy distribution during D-T operation in 1993--94. A series of preliminary experiments are planned to test the diagnostic concept. The first experiments will observe neutrals from beam-injected deuterium ions and the high energy 3He tail produced during ICH minority heating on TFTR interacting with the cloud. We will also monitor by line radiation the charge state distributions in lithium, boron, and carbon clouds

  8. Intercomparison of alpha particle spectrometry software packages

    International Nuclear Information System (INIS)

    Software has reached an important level as the 'logical controller' at different levels, from a single instrument to an entire computer-controlled experiment. This is also the case for software packages in nuclear instruments and experiments. In particular, because of the range of applications of alpha-particle spectrometry, software packages in this field are often used. It is the aim of this intercomparison to test and describe the abilities of four such software packages. The main objectives of the intercomparison were the ability of the programs to determine the peak areas and the peak area uncertainties, and the statistical control and stability of reported results. In this report, the task, methods and results of the intercomparison are presented in order to asist the potential users of such software and to stimulate the development of even better alpha-particle spectrum analysis software

  9. Impact of ICRH on the measurement of fusion alphas by collective Thomson scattering in ITER

    DEFF Research Database (Denmark)

    Salewski, Mirko; Eriksson, L.-G.; Bindslev, Henrik;

    2009-01-01

    Collective Thomson scattering (CTS) has been proposed for measuring the phase space distributions of confined fast ion populations in ITER plasmas. This study determines the impact of fast ions accelerated by ion cyclotron resonance heating (ICRH) on the ability of CTS to diagnose fusion alphas......, corresponding to an off-axis resonance. The sensitivities of the results to the He-3 concentration (0.1-4%) and the heating power (20-40 MW) are considered. Fusion born alphas dominate the total CTS signal for large Doppler shifts of the scattered radiation. The tritons generate a negligible fraction...... perpendicular velocities, it may be difficult to draw conclusions about the physics of alpha particles alone by CTS. With this exception, the CTS diagnostic can reveal the physics of the fusion alphas in ITER even under the presence of fast ions due to ICRH....

  10. Single particle level scheme for alpha decay

    International Nuclear Information System (INIS)

    The fine structure phenomenon in alpha decay was evidenced by Rosenblum. In this process the kinetic energy of the emitted particle has several determined values related to the structure of the parent and the daughter nucleus. The probability to find the daughter in a low lying state was considered strongly dependent on the spectroscopic factor defined as the square of overlap between the wave function of the parent in the ground state and the wave functions of the specific excited states of the daughter. This treatment provides a qualitative agreement with the experimental results if the variations of the penetrability between different excited states are neglected. Based on single particle structure during fission, a new formalism explained quantitatively the fine structure of the cluster decay. It was suggested that this formalism can be applied also to alpha decay. For this purpose, the first step is to construct the level scheme of this type of decay. Such a scheme, obtained with the super-asymmetric two-center potential, is plotted for the alpha decay of 223Ra. It is interesting to note that, diabatically, the level with spin 3/2 emerging from 1i11/2 (ground state of the parent) reaches an excited state of the daughter in agreement with the experiment. (author)

  11. Track-nanodosimetry of an alpha particle

    Energy Technology Data Exchange (ETDEWEB)

    De Nardo, L.; Tornielli, G. [Padova Univ., Padova (Italy); INFN, Padova (Italy); Cesari, V.; Colautti, P.; Conte, V. [INFN Laboratori Nazionali, Legnaro (Italy); Baek, W.Y.; Grosswendt, B. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Alkaa, A.; Segur, P. [Centre de Physique des Plasmas et de leur Applications, Toulouse (France)

    2002-07-01

    Effects of radiation are primarily determined by what happens in individual small volumes representative of DNA segments. Such sites are so small that the interactions due to radiation are very few and it is necessary to consider the stochastic of the number and nature of primary interactions and of secondary processes in order to understand the subsequent biological effects. Track-nanodosimetry has the objective to investigate stochastic aspect of energy deposition in particle tracks, by measuring the ionisation distributions induced by a charged particle in nanometric volumes of tissue-equivalent matter, positioned at different distances from the track. This paper is concerned with measurements and Monte Carlo calculations of ionisation distributions produced in a site of about 20 nm by a {sup 244}Cm alpha particle.

  12. Track-nanodosimetry of an alpha particle

    International Nuclear Information System (INIS)

    Effects of radiation are primarily determined by what happens in individual small volumes representative of DNA segments. Such sites are so small that the interactions due to radiation are very few and it is necessary to consider the stochastic of the number and nature of primary interactions and of secondary processes in order to understand the subsequent biological effects. Track-nanodosimetry has the objective to investigate stochastic aspect of energy deposition in particle tracks, by measuring the ionisation distributions induced by a charged particle in nanometric volumes of tissue-equivalent matter, positioned at different distances from the track. This paper is concerned with measurements and Monte Carlo calculations of ionisation distributions produced in a site of about 20 nm by a 244Cm alpha particle

  13. The Fission of Thorium with Alpha Particles

    Energy Technology Data Exchange (ETDEWEB)

    Newton, Amos S.

    1948-04-15

    The fission distribution of fission of thorium with alpha particle of average energy 37.5 Mev has been measured by the chemical method. The distribution found shows that the characteristic dip in the fission yield mass spectrum has been raised to within a factor of two of the peaks compared to a factor of 600 in slow neutron fission of U{sup 235}. The raise in the deip has caused a corresponding lowering in fission yield of these elements at the peaks. The cross section for fission of thorium with 37.5 Mev alphas was found to be about 0.6 barn, and the threshold for fission was found to be 23 to 24 Mev.

  14. Track nanodosimetry of an alpha particle

    International Nuclear Information System (INIS)

    Experimental measurements and calculations are described of ionisation distributions in propane wall-less gas cavities of about 20 nm simulated size, performed at different distances from a 244Cm alpha particle track. Ionisation events are detected one by one by collecting electrons from the sensitive volume and by separating them with a drift column. Experimental results and Monte Carlo calculations indicate that, in the delta ray cloud, conditional probability curves, average cluster size and the ratio of second moment above first moment of the cluster distribution are invariant with track distance. (author)

  15. Track nanodosimetry of an alpha particle.

    Science.gov (United States)

    De Nardo, L; Colautti, P; Baek, W Y; Grosswendt, B; Alkaa, A; Ségur, P; Tornielli, G

    2002-01-01

    Experimental measurements and calculations are described of ionisation distributions in propane wall-less gas cavities of about 20 nm simulated size, performed at different distances from a 244Cm alpha particle track. Ionisation events are detected one by one by collecting electrons from the sensitive volume and by separating them with a drift column. Experimental results and Monte Carlo calculations indicate that, in the delta ray cloud, conditional probability curves, average cluster size and the ratio of second moment above first moment of the cluster distribution are invariant with track distance. PMID:12194323

  16. Track nanodosimetry of an alpha particle

    Energy Technology Data Exchange (ETDEWEB)

    De Nardo, L.; Colautti, P.; Baek, W.Y.; Grosswendt, B.; Alkaa, A.; Segur, P.; Tornielli, G

    2002-07-01

    Experimental measurements and calculations are described of ionisation distributions in propane wall-less gas cavities of about 20 nm simulated size, performed at different distances from a {sup 244}Cm alpha particle track. Ionisation events are detected one by one by collecting electrons from the sensitive volume and by separating them with a drift column. Experimental results and Monte Carlo calculations indicate that, in the delta ray cloud, conditional probability curves, average cluster size and the ratio of second moment above first moment of the cluster distribution are invariant with track distance. (author)

  17. Superparamagnetic relaxation in alpha-Fe particles

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen; Pedersen, Michael Stanley; Svedlindh, P.; Jonsson, G.T.; Garcia-Palacios, J.L.; Lazaro, F.J.

    1998-01-01

    The superparamagnetic relaxation time of carbon-supported alpha-Fe particles with an average size of 3.0 Mm has been studied over a large temperature range by the use of Mossbauer spectroscopy combined with AC and DC magnetization measurements. It is found that the relaxation time varies with...... temperature in accordance with Ni el's expression, tau = tau(0) exp (KV/kT) with tau(0) = (1.0 +/- 0.5) x 10(-10) s and K = (1.2 +/- 0.2) x 10(5) J m(-3). (C) 1998 Elsevier Science B.V. All rights reserved....

  18. Global alpha-particle optical potentials

    International Nuclear Information System (INIS)

    A search for a global optical potential for alpha-particles is described. It did not prove possible to find such a potential valid for a wide range of energies and nuclei, even treating the absorbing potential as an adjustable parameter for each nucleus. For practical purposes the best that can be done is to define an average potential, and such a potential is compared with a wide range of experimental data. Its energy variation is determined by fitting the total reaction cross-section. (author). 7 refs, 15 figs, 1 tab

  19. Scattering of light by nonspherical particles

    International Nuclear Information System (INIS)

    Methods of computing scattering by non-spherical particles are reviewed for the Mie theory, the Rayleigh-Gans approximation, the geometric optics method, the extended boundary condition method, the anamalous diffraction, the suppression of resonances, the statistical approach, the expansion of vector wave equations in spheroidal coordinates, and the semi-emperical theory of Pollack and Cuzzi. The results of computations for nonspherical particles are compared for prolate and oblate spheroids, homogeneous sphere with holes, rough particles made of stacked cylinders, irregular particles of various shapes, and particles of carbonaceous smokes. Conclusions are presented in the context of nuclear winter

  20. Non-forward scattering of twisted particles

    CERN Document Server

    Ivanov, I P

    2011-01-01

    Twisted photons (i.e. photons carrying non-zero orbital angular momentum) are well-known in optics. Recently, it was suggested to use Compton backscattering off an ultra-relativistic electron beam to boost optical twisted photons into the high energy range. However, only the case of strictly forward/backward scattering has been studied so far. Here, we consider generic kinematic features of processes in which a twisted particle scatters with non-zero transverse momentum transfer.

  1. Alpha particle loss in the TFTR DT experiments

    International Nuclear Information System (INIS)

    Alpha particle loss was measured during the TFTR DT experiments using a scintillator detector located at the vessel bottom in the ion grad-B drift direction. The DT alpha particle loss to this detector was consistent with the calculated first-orbit loss over the whole range of plasma current I=0.6-2.7 MA. In particular, the alpha particle loss rate per DT neutron did not increase significantly with fusion power up to 10.7 MW, indicating the absence of any new ''collective'' alpha particle loss processes in these experiments

  2. Chromosomal aberrations induced by alpha particles

    International Nuclear Information System (INIS)

    The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

  3. Scattering by ensembles of small particles

    International Nuclear Information System (INIS)

    With the advent of high altitude rockets and of space probes, evidence has accumulated that several particle types coexiste in the interplanetary medium. It also became apparent that the zodiacal light is not produced by particles with previously known scattering characteristics. However, the scattering is here shown to be consistent with the hypothesis that presolar interstellar grains accumulate into comets which through fragmentation provide a major component of the interplanetary dust complex. Cometary debris - zodiscal light particles - are therefore modeled as conglomerates of elongated core-mantle particles. Light scattering characteristics of the conglomerates are investigated using a micro-wave analogue method. Approximate theoretical methods for prediction and interpretation of the electro-magnetic scattering patterns are developed and are found to compare favorably with the experimental results and with observations of the zodiacal light. The model is also found to be consistent with comet- and impactdata. Dynamical considerations predicts a small particle component rapidly receding from the Sun, an identification with the B-meteoroids is tentatively suggested. (author)

  4. Study of giant resonances at high excitation energy by alpha inelastic scattering

    International Nuclear Information System (INIS)

    Angular distributions of 340 and 480 MeV alpha particles inelastically scattered by 208Pb, 116Sn and 58Ni up to 60 MeV of excitation have been measured. The experimental inelastic spectra have been analysed by means of a new global method. The repartition of multipole strength shows the already known low energy giant resonances into more details. New high energy giant resonances are observed

  5. Lorentz alpha orbit calculation in search of position suitable for escaping alpha particle diagnostics in ITER

    International Nuclear Information System (INIS)

    The Lorentz orbit code is developed to understand escaping alpha particle orbits and to contribute to the design of an escaping alpha particle probe in ITER. The code follows the full gyromotion of an alpha particle in ITER equilibrium, considering the toroidal field magnetic field ripple produced by the finite number of toroidal field coils as well as full three-dimensional first wall panels placed at the outboard side of the torus. It is shown that alpha particles that exist in the peripheral region and have banana orbits intersect the first wall placed at the outboard side on the lower plane. (author)

  6. Born expansions for charged particle scattering

    International Nuclear Information System (INIS)

    High-order terms in Born expansions of scattering amplitudes in powers of charge are frequently divergent when long-range Coulomb interactions are present asymptotically. Expansions which are free from these logarithmic divergences have been constructed recently. This paper illustrates these expansions with the simplest example, namely the non-relativistic Rutherford scattering of two charged particles. This approach represents an adequate framework for the calculation of transition amplitudes and a comprehensive starting point for the development of consistent perturbation approximations in multi-channel descriptions of strongly interacting atomic systems

  7. Multijet production in neutral current deep inelastic scattering at HERA and determination of alpha_s

    CERN Document Server

    Abramowicz, H; Adamczyk, L; Adamus, M; Adler, V; Aghuzumtsyan, G; Allfrey, P D; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P M; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Freiburgi, B; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Büttner, C; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Catterall, C D; Chekanov, S; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danilov, P; De Pasquale, S; Dementiev, R K; Derrick, M; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Everett, A; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Goers, S; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Grigorescu, G; Grijpink, S; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Hilger, E; Hochman, D; Holm, U; Horn, C; Iacobucci, G; Iga, Y; Irrgang, P; Jakob, P; Jiménez, M; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karshon, U; Karstens, F; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhav--, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal--, H; Kramberger, G; Kreisel, A; Krumnack, N; Kulinski, P; Kuze, M; Kuzmin, V A; Labarga, L; Lammers, S; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Limentani, S; Ling, T Y; Liu, C; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Ma, K J; Maddox, E; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Olkiewicz, K; Ota, O; Padhi, S; Palmonari, F; Patel, S; Paul, E; Pavel, Usan; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plamondon, M; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Robins, S; Rosin, M; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Santamarta, R; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett--, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Tyszkiewicz, A; Ukleja, A; Ukleja, J; Vázquez, M; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Whitmore, J J; Whyte, J; Wichmann, K; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wlasenko, M; Wolf, G; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Za, L; Zambrana, M; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Ziegler, A; Zotkin, D S; Zotkin, S A; De Favereau, J; De Wolf, E; Del Peso, J

    2005-01-01

    Multijet production rates in neutral current deep inelastic scattering have been measured in the range of exchanged boson virtualities 10 5 GeV and -1 < eta_{LAB}{jet} < 2.5. Next-to-leading-order QCD calculations describe the data well. The value of the strong coupling constant alpha_s(M_Z), determined from the ratio of the trijet to dijet cross sections, is alpha_s(M_Z) = 0.1179 pm 0.0013(stat.) {+0.0028}_{-0.0046}(exp.) {+0.0064}_{-0.0046}(th.)

  8. Determination of $\\alpha_s$ and $m_c$ in deep-inelastic scattering

    CERN Document Server

    Alekhin, S; Moch, S

    2013-01-01

    We describe the determination of the strong coupling constant $\\alpha_s(M_Z^2)$ and of the charm-quark mass $m_c(m_c)$ in the $\\bar{\\rm MS}$-scheme, based on the QCD analysis of the unpolarized World deep-inelastic scattering data. At NNLO the values of $\\alpha_s(M_Z^2)=0.1134\\pm 0.0011(\\text{exp})$ and $m_c(m_c)=1.24 \\pm 0.03 (\\text{exp})\\,^{+0.03}_{-0.02} (\\text{scale})\\,^{+0.00}_{-0.07} (\\text{th})$ are obtained and are compared with other determinations, also clarifying discrepancies.

  9. Alpha particle radiography of ants using a 244Cm alpha source

    International Nuclear Information System (INIS)

    Alpha particles emitted from a radioisotope 244Cm were used for the radiography of ants. Cellulose nitrate films, LR-115 from Kodak Pathe, were used as solid state nuclear track detectors to make the radiographs. Alpha particles of energies from 3.5 to 5.5 MeV were obtained by varying the air spacing between the 244Cm and the sample with stainless steel spacers of thickness from 2.4 to 0.5 cm to slow the 5.81 MeV alpha particles from the 244Cm by air. The resulting radiographs of the ants put on the LR-115 films and irradiated by alpha particles of different energies show that only the profiles of the ants were obtained when the ants were exposed to alpha particles of energies lower than 3.5 MeV, and almost all parts of the ant except a portion in the head were penetrated by alpha particles of energies higher than 5.0 MeV to register high density alpha tracks on the LR-115. The details of the internal organs of the ant can be shown clearly by radiography with alpha particles of energies between 4.0 and 5.0 MeV. (author)

  10. The Effects of Alpha Particle Confinement on Burning Plasma Tokamak Performance

    Science.gov (United States)

    Gormley, Robert P.

    thermal stability of a fusion reactor are also discussed. Lastly, we calculate the alpha particle induced bootstrap current produced, while retaining the effects of slowing-down drag, pitch-angle scattering, and arbitrary aspect ratio. The alpha drift kinetic equation is solved for the alpha bootstrap current density; and the resulting expression inserted into a simple cylindrical Ampere's Law. In addition, the alpha bootstrap current is more rigorously solved, self-consistently, with the full 2-D Grad-Shafranov equilibrium equations for three currently conceived tokamaks: TPX, ITER-CDA and ITER-EDA. In particular, the effect of varying plasma Zeff on the alpha bootstrap current is investigated. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617 -253-5668; Fax 617-253-1690.).

  11. Detection of alpha particles with undoped poly (ethylene naphthalate)

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hidehito, E-mail: hidehito@rri.kyoto-u.ac.jp [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shirakawa, Yoshiyuki; Kitamura, Hisashi [National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Sato, Nobuhiro; Takahashi, Sentaro [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)

    2014-03-01

    There has been recent interest in the use of undoped, aromatic-ring polymers as organic scintillation materials for radiation detectors. Here, we characterise the response of poly (ethylene naphthalate) (PEN) to alpha particles. The energy response to 5486 keV alpha particles emitted from {sup 241}Am was 554±45 keV electron equivalents (keVee), with an energy resolution of 11.2±0.1%. The energy response to 6118 keV alpha particles emitted from {sup 252}Cf was 618±45 keVee, with a resolution of 8.8±0.1%. It is also important to characterise the refractive index because it determines how efficiently light propagates in scintillation materials to the photodetector. By taking into account the PEN emission spectrum, it was revealed that its effective refractive index was 1.70. Overall, the results indicate that PEN has potential as a scintillation material for the detection of alpha particles. - Highlights: • PEN is characterised as a scintillation material for alpha particles. • The effective refractive index for PEN is 1.70 in its emission spectrum. • The response to 5486 (6118) keV alpha particles was 554±45 (618±45) keVee. • The energy resolution for 5486 (6118) keV alpha particles was 11.2±0.1 (8.8±0.1) %. • This work will stimulate future use of PEN for radiation detection.

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

    Energy Technology Data Exchange (ETDEWEB)

    Tran, H.N., E-mail: tranngochoang@tdt.edu.vn [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); El Bitar, Z. [Institut Pluridisciplinaire Hubert Curien/IN2P3/CNRS, Strasbourg (France); Champion, C. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Karamitros, M. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, INCIA, UMR 5287, F-33400 Talence (France); Bernal, M.A. [Instituto de FísicaGleb Wataghin, Universida de Estadual de Campinas, SP (Brazil); Francis, Z. [Université Saint Joseph, Faculty of Science, Department of Physics, Beirut (Lebanon); The Open University, Faculty of Science, Department of Physical Sciences, Walton Hall, MK7 6AA Milton Keynes (United Kingdom); Ivantchenko, V. [Ecoanalytica, 119899 Moscow (Russian Federation); Lee, S.B.; Shin, J.I. [Proton Therapy Center, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769 (Korea, Republic of); Incerti, S. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France)

    2015-01-15

    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.

  13. Scintillation of thin tetraphenyl butadiene films under alpha particle excitation

    CERN Document Server

    Pollmann, Tina; Kuźniak, Marcin

    2010-01-01

    The alpha induced scintillation of the wavelength shifter 1,1,4,4-tetraphenyl-1,3-butadiene (TPB) was studied to improve the understanding of possible surface alpha backgrounds in the DEAP dark matter search experiment. We found that vacuum deposited thin TPB films emit 882 +/-210 photons per MeV under alpha particle excitation. The scintillation pulse shape consists of a double exponential decay with lifetimes of 11 +/-5 ns and 275 +/-10ns.

  14. The 1997 IAEA test spectra for alpha-particle spectrometry

    CERN Document Server

    Garcia-Torano, E; Woods, S; Blaauw, M; Fazinic, S

    1999-01-01

    In the framework of an IAEA intercomparison of software for alpha-particle spectrometry, a set of test spectra with reference files was produced for validation and comparison of alpha spectrum analysis programs. The considerations, the spectra and the methods employed to obtain them are presented.

  15. Luminescence imaging of water during alpha particle irradiation

    Science.gov (United States)

    Yamamoto, Seiichi; Komori, Masataka; Koyama, Shuji; Toshito, Toshiyuki

    2016-05-01

    The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of 241Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

  16. A theory of scattering for quasifree particles

    CERN Document Server

    Streater, Raymond F

    2015-01-01

    In this book, the author presents the theory of quasifree quantum fields and argues that they could provide non-zero scattering for some particles. The free-field representation of the quantised transverse electromagnetic field is not closed in the weak*-topology. Its closure contains soliton-anti-soliton pairs as limits of two-photon states as time goes to infinity, and the overlap probability can be computed using Uhlmann''s prescription. There are no free parameters: the probability is determined with no requirement to specify any coupling constant. All cases of the Shale transforms of the

  17. Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN

    CERN Document Server

    Fujiwara, M C; Bertsche, W; Bowe, P D; Bray, C C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Funakoshi, R; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Lai, W; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; Van der Werf, D P; Wasilenko, L; Wurtele, J S; Yamazaki, Y

    2008-01-01

    We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen is trapped, could provide competitive tests of CPT, possibly probing physics at the Planck Scale. We discuss some of the particle detection techniques used in ALPHA. Preliminary results from commissioning studies of a partial system of the ALPHA Si vertex detector are presented, the results of which highlight the power of annihilation vertex detection capability in antihydrogen studies.

  18. An evaluation of alpha particle clustering in heavy nuclei

    International Nuclear Information System (INIS)

    In recent years, the pre-equilibrium models of nuclear reactions have been used to analyze many experiments involving the emission of alpha particles. The results of these analyses have been used as the basis for a calculation of the extent of alpha particle clustering in heavy nuclei. Calculations are presented of the rate of nucleon-nucleon and nucleon-alpha interactions in nuclear matter. Normalizing these to the preformation factors found in reaction studies, the number of alpha clusters in several complex nuclei has been obtained. It is suggested that the number of such performed alpha clusters in nuclei having A = 50, 90, 141, 202, and 232 are, respectively, 2.1, 3.6, 5.2, 6.9, and 7.8. (orig.) 891 FKS/orig. 892 MB

  19. Light Scattering by Optically Soft Particles Theory and Applications

    CERN Document Server

    Sharma, Subodh K

    2006-01-01

    The present monograph deals with a particular class of approximation methods in the context of light scattering by small particles. This class of approximations has been termed as eikonal or soft particle approximations. The eikonal approximation was studied extensively in the potential scattering and then adopted in optical scattering problems. In this context, the eikonal and other soft particle approximations pertain to scatterers whose relative refractive index compared to surrounding medium is close to unity. The study of these approximations is very important because soft particles occur abundantly in nature. For example, the particles that occur in ocean optics, biomedical optics, atmospheric optics and in many industrial applications can be classified as soft particles. This book was written in recognition of the long-standing and current interest in the field of scattering approximations for soft particles. It should prove to be a useful addition for researchers in the field of light scattering.

  20. Alpha-particle diagnostics with high energy neutral beams

    International Nuclear Information System (INIS)

    We have examined the feasibility of alpha-particle diagnostics using a high energy neutral beam on the R-tokamak, a planned device at IPP-Nagoya, Japan, for reacting plasma experiments. In this method, injected neutral particles neutralize alpha particles so as to escape from the magnetically confined plasma through double charge exchange processes, He++ + A0 -- → He0 + A++. Requirements for a probing beam are dis cussed from viewpoints of penetration of an injected beam in the plasma and a neutralization efficiency of alpha particles in a wide velocity range. Either a Li0 beam or a He0 beam in the ground state, produced from a negative ion beam is suitable. A method to neutralize a He- beam into the ground state through an auto-detachment process is proposed. (author)

  1. Analysis of radiation risk from alpha particle component of soalr particle events

    Science.gov (United States)

    Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Golightly, M. J.; Weyland, M.

    1994-01-01

    The Solar Particle Events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and Linear Energy Transfer (LET) spectra in shielding are discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.

  2. Analysis of radiation risk from alpha particle component of solar particle events

    Science.gov (United States)

    Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Golightly, M. J.; Weyland, M.

    1994-01-01

    The solar particle events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and linear energy transfer (LET) spectra in shielding discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.

  3. Fluorescent scattering by molecules embedded in small particles

    International Nuclear Information System (INIS)

    Studies are reported in these areas: double resonance in fluorescent and Raman scattering; surface enhanced Raman scattering; fluorescence by molecules embedded in small particles; fluorescence by a liquid droplet; and fluorescence by conical pits in surfaces

  4. Alpha particle destabilization of the TAE modes

    International Nuclear Information System (INIS)

    The high frequency, low mode number toroidicity-induced Alfven eigenmodes (TAE) are shown to be driven unstable by the circulating and/or trapped α-particles through the wave-particle resonances. For a poloidal harmonic to satisfy the resonance condition it requires that the α-particle birth speed vα ≥ vA/(2|m-nq|), where vA is the Alfven speed, m is the poloidal mode number, and n is the toroidal mode number. To destabilize the TAE modes, the inverse Landau damping associated with the α-particle pressure gradient free energy must overcome the velocity space Landau damping due to both the slowing-down α-particle and the core Maxwellian electron and ion distributions. Stability criteria in terms of the α-particle beta βα, α-particle pressure gradient parameter (ω*/ωA) (ω* is the α-particle diamagnetic drift frequency), and (vα/vA) parameters are presented for TFTR, CIT, and ITER tokamaks. The volume averaged α-particle beta threshold for TAE instability also depends sensitively on the core electron and ion temperature. Typically the volume averaged α-particle beta threshold is in the order of 10-4 if the continuum damping effect is absent. Typical growth rates of the n = 1 TAE mode can be in the order of 10-2ωA, where ωA = vA/qR. Stability of higher n TAE modes is also studied. Other types of global Alfven waves are stable due to sideband mode continuum damping resulting from toroidal coupling effects. If the Alfven continuum gap does not exist across the whole minor radius, continuum damping exists for some poloidal harmonics. The continuum damping effect is studied by employing both a resistive MHD stability code (NOVA-R) and an analytical matching method, and the results are presented. 1 ref

  5. Ionization cluster size distribution for alpha particles: Experiment, modelling

    International Nuclear Information System (INIS)

    The paper presents data for measured ionization cluster size distributions by alpha particles in tissue equivalent media and comparison with the simulated data for liquid water. The experiments were carried out with a beam of 4.6 MeV alpha particles performed in a setup called the JET Counter. The theoretically derived cluster size distributions for alphas particles were obtained using the K-means algorithm. The simulation was carried out by Monte Carlo track structure calculations using cross sections for liquid water. The first moments of cluster size distributions, derived from K-means algorithm as a function of diameter of cluster centroid, were compared with the corresponding moments derived from the experiments for nitrogen and propane targets. It was found that the ratio of the first moments for water to gas targets correlates well with the corresponding ratio of the mean free paths for primary ionization by alpha particles in the two media. It is shown that the cluster size distributions for alpha particles in water, obtained from K-means algorithm, are in agreement with the corresponding distributions measured experimentally in nitrogen or propane gas targets of nano-meter sizes. (authors)

  6. Resonance scattering characteristics of double-layer spherical particles

    Institute of Scientific and Technical Information of China (English)

    Xuejin Dong; Mingxu Su; Xiaoshu Cai

    2012-01-01

    Based on the principle of ultrasonic resonance scattering,sound-scattering characteristics of double-layer spherical particles in water were numerically studied in this paper.By solving the equations of the scattering matrix,the scattering coefficient determined by the boundary conditions can be obtained,thus the expression for the sound-scattering function of a single double-layer spherical particle can be derived.To describe the resonance scattering characteristics of a single particle,the reduced scattering cross section and reduced extinction cross section curves were found through numerical calculation.Similarly,the numerically calculated sound attenuation coefficient curves were used to depict the resonance scattering characteristics of monodisperse and polydisperse particles.The results of numerical calculation showed that,for monodisperse particles,the strength of the resonance was mainly related to the particle size and the total number of particles; while for polydisperse particles,it was primarily affected by the particle size,the coverage of the particle size distribution and the particle concentration.

  7. Comparative study of alpha + nucleus elastic scattering using different models

    International Nuclear Information System (INIS)

    The alpha (α) elastic scattering from different targets potential over the energy range 10–240 MeV has been analyzed in the framework of the single-folding (SF) optical model. Four targets are considered, namely, 24Mg, 28Si, 32S and 40Ca. The SF calculations for the real central part of the nuclear optical potential are performed by folding an effective α–α interaction with the α-cluster distribution density in the target nucleus. The imaginary part of the optical potential is expressed in the phenomenological Woods–Saxon (WS) form. The calculated angular distributions of the elastic scattering differential cross-section using the derived semimicroscopic potentials successfully reproduce 36 sets of data all over the measured angular ranges. The obtained results confirm the validity of the α-cluster structure of the considered nuclei. For the sake of comparison, the same sets of data are reanalyzed using microscopic double-folded optical potentials based upon the density-dependent Jeukenne–Lejeune–Mahaux (JLM) effective nucleon–nucleon interaction. (author)

  8. Discrimination of nuclear recoils from alpha particles with superheated liquids

    Energy Technology Data Exchange (ETDEWEB)

    Aubin, F; Auger, M; Genest, M-H; Giroux, G; Gornea, R; Faust, R; Leroy, C; Lessard, L; Martin, J-P; Morlat, T; Piro, M-C; Starinski, N; Zacek, V [Departement de Physique, Universite de Montreal, Montreal, H3C 3J7 (Canada); Beltran, B; Krauss, C B [Department of Physics, University of Alberta, Edmonton, T6G 2G7 (Canada); Behnke, E; Levine, I; Shepherd, T [Department of Physics and Astronomy, Indiana University South Bend, South Bend, IN 46634 (United States); Nadeau, P; Wichoski, U [Department of Physics, Laurentian University, Sudbury, P3E 2C6 (Canada)], E-mail: zacekv@lps.umontreal.ca (and others)

    2008-10-15

    The PICASSO collaboration observed for the first time a significant difference between the acoustic signals induced by neutrons and alpha particles in a detector based on superheated liquids. This new discovery offers the possibility of improved background suppression and could be especially useful for dark matter experiments. This new effect may be attributed to the formation of multiple bubbles on alpha tracks, compared to single nucleations created by neutron-induced recoils.

  9. Nuclear track detector characterization for alpha-particle spectroscopy

    International Nuclear Information System (INIS)

    Solid State Nuclear Track Detectors (SSNTDs), CR-39™ type, are usually adopted in many applications in which it could be necessary to select tracks according to the incident alpha-particle energy; so several authors have argued that track parameters such as the major/minor axis being the most often reported, can be used to determine the alpha-particle’s energy. However, the use of these parameters only do an univocal result, for example the same axis length can be obtained for different combinations of incident angles and energies. We report on a track analysis performed by a semiautomatic system that classifies tracks according to two parameters, diameter length and mean grey level. This kind of analysis can give information about the track depth, that increases monotonically with the incident energy and angle of the alpha particle. Combining the information on the two parameters it is possible to determine univocally the incident alpha-particle energy values. In order to characterize CR-39 detectors according to the physical track parameters, detectors were irradiated, inside a vacuum chamber, by alpha particles at thirteen energy values, obtained by different mylar layers in front of a 241Am source. After the exposure the detectors were chemically etched to enlarge the tracks and then analyzed by means of a semiautomatic system, consisting on an optical microscope equipped with a CCD camera connected to a personal computer for image storage. A suitable routine analyzed the track parameters: diameter and mean grey level, allowing us to differentiate tracks according to the incident alpha-particle energy and then to individuate the discrimination factors for radon alpha tracks, when nuclear track detectors are applied in radon surveys. - Highlights: ► CR-39. ► Geometric and optical parameter. ► α spectrometry. ► Calibration

  10. Radon monitor and control system based upon alpha particle detection

    International Nuclear Information System (INIS)

    A system is designed for monitoring or controlling the level of radon in indoor air, based upon measuring alpha particles due to the decay of radon or its daughter atoms. In one embodiment, the alpha particle decay of radon itself is detected and analyzed to control a vent in the heating and air conditioning system to automatically keep the radon level below a preselected level. In another embodiment, the daughter atoms 218Po and 214Po are collected from the indoor air and their alpha particle decays are analyzed to provide a sensitive monitor of radon levels or to control vents in the HVAC system to reduce radon concentrations to permissible levels. In addition, the system provides information on the quality of the air filter and indicates when it needs servicing

  11. Alpha-particle radiobiological experiments using thin CR-39 detectors

    International Nuclear Information System (INIS)

    The present paper studied the feasibility of applying comet assay to evaluate the DNA damage in individual HeLa cervix cancer cells after alpha-particle irradiation. We prepared thin CR-39 detectors (<20 μm) as cell-culture substrates, with UV irradiation to shorten the track formation time. After irradiation of the HeLa cells by alpha particles, the tracks on the underside of the CR-39 detector were developed by chemical etching in (while floating on) a 14 N KOH solution at 37 deg. C. Comet assay was then applied. Diffusion of DNA out of the cells could be generally observed from the images of stained DNA. The alpha-particle tracks corresponding to the comets developed on the underside of the CR-39 detectors could also be observed by just changing the focal plane of the confocal microscope. (authors)

  12. Turbulent transport of alpha particles in tokamak plasmas

    CERN Document Server

    Croitoru, A; Vlad, M; Spineanu, F

    2016-01-01

    We investigate the ExB diffusion of fusion born \\alpha particles in tokamak plasmas. We determine the transport regimes for a realistic model that has the characteristics of the ion temperature gradient (ITG) or of the trapped electron modes (TEM) driven turbulence. It includes a spectrum of potential fluctuations that is modeled using the results of the numerical simulations, the drift of the potential with the effective diamagnetic velocity and the parallel motion. Our semi-analytical statistical approach is based on the decorrelation trajectory method (DTM), which is adapted to the gyrokinetic approximation. We obtain the transport coefficients as a function of the parameters of the turbulence and of the energy of the \\alpha particle. According to our results, signficant turbulent transport of the \\alpha particles can appear only at energies of the order of 100KeV. We determine the corresponding conditions.

  13. Performance comparison of scintillators for alpha particle detectors

    Science.gov (United States)

    Morishita, Yuki; Yamamoto, Seiichi; Izaki, Kenji; Kaneko, Junichi H.; Toui, Kohei; Tsubota, Youichi; Higuchi, Mikio

    2014-11-01

    Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd2Si2O7 (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo-multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under test and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM

  14. Relativistic multichannel scattering theory with particle creation

    International Nuclear Information System (INIS)

    The creation of a mathematical rigorous multichannel relativistic quantum scattering theory that includes particle creation and annihilation has been an important goal in theoretical physics for many decades. This problem with a different perspective from the main traditional approaches is reexamined. In particular, it is not a quantum field theory nor is it based on the Bakamjian-Thomas construction. As fundamental interaction a traditional Yukawa-type interaction in which a meson is emitted or absorbed by a nucleon was considered. A vertex function in this interaction is included. The nucleon number is conserved and no antinucleons. The fundamental Hilbert space has the usual Fock-space structure that accommodate a variable number of mesons. The Yukawa nature of the fundamental interaction implies that the nucleons of the Hamiltonian and the fundamental Hilbert space must be bare particles. On the other hand, the asymptotically observed nucleons are dressed, implying that the Fock space of asymptotic states is distinct from fundamental Hilbert space; then it was necessary to consider a two-Hilbert space theory. How to construct the Hilbert space framework for a simplified system consisting of a single bare nucleon and an indeterminated number of a single type of meson is shown. The spin and charge of the nucleon was ignored, the meson is its own antiparticle and has zero charge and spin. 9 refs. (nevyjel)

  15. Alpha scattering and capture reactions in the A = 7 system at low energies

    OpenAIRE

    Mohr, P; Abele, H.; ZWIEBEL, R.; Staudt, G.; Krauss, H; Oberhummer, H.; Denker, A; Hammer, J. W.; Wolf, G.

    1993-01-01

    Differential cross sections for $^3$He-$\\alpha$ scattering were measured in the energy range up to 3 MeV. These data together with other available experimental results for $^3$He $+ \\alpha$ and $^3$H $+ \\alpha$ scattering were analyzed in the framework of the optical model using double-folded potentials. The optical potentials obtained were used to calculate the astrophysical S-factors of the capture reactions $^3$He$(\\alpha,\\gamma)^7$Be and $^3$H$(\\alpha,\\gamma)^7$Li, and the branching ratio...

  16. Development of low level alpha particle counting system

    International Nuclear Information System (INIS)

    Much attention has been paid to the trace analysis of uranium and thorium contained in the base material of LSI or VLSI, since the so-called ''soft-error'' of the memory device was known to be due to alpha particles emitted from these radioactive elements. We have developed an apparatus to meet the needs of estimating such a very small quantity of U and Th of the level of ppb, by directly counting alpha particles using a gas-flow type proportional counter. This method requires no sophisticated analytical skill, and the accuracy of the result is satisfactory. The instrumentation and some application of this apparatus are described. (author)

  17. Nuclear reaction diagnostics of fast confined and escaping alpha particles

    International Nuclear Information System (INIS)

    The resonant radiative capture nuclear reactions D(α,γ)6Li, 6Li(α,γ) 19B and 7Li(α,γ)11B are examined as diagnostics of the energy distribution of confined fast alpha particles in tokamak plasmas. Count rates for realistic Q=1 DT plasma conditions are presented and compared to expected backgrounds. The design of and preliminary results from the prototype fusion gamma ray detector on TFTR are presented. The activation reactions are similarly examined as diagnostics of escaping fast alpha particles. Where possible, count rate estimates for Q=1 DT plasmas and proposed ignition devices are presented

  18. Alpha-particle condensation in nuclei

    International Nuclear Information System (INIS)

    A round up of the present status of the conjecture that nα nuclei form an α-particle condensate in excited states close to the nα threshold is given. Experiments which could demonstrate the condensate character are proposed. Possible lines of further theoretical developments are discussed. (authors)

  19. Alpha-particle condensation in nuclei

    International Nuclear Information System (INIS)

    A round-up of the present status of the conjecture that nα nuclei form an α-particle condensate in excited states close to the nα threshold is given. Experiments which could demonstrate the condensate character are proposed. Possible lines of further theoretical developments are discussed. (author)

  20. Instrument for measuring total alpha particle energies of alpha emitters in ambient air

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, S.; Brucker, G.J.; Cummings, B.; Bechtel, E.; Gentner, F.; Horne, S

    2000-11-11

    This paper describes the design, fabrication, testing and evaluation of a self-reading, carbon fiber, electrometer-type instrument. It is used for measuring the total energy of alpha particles emitted in air by progenies of {sup 222}Rn ({sup 218}Po, {sup 214}Pb, and {sup 214}Bi), and sometimes by other types of alpha emitters (e.g. {sup 212}Pb, {sup 238}U, and {sup 239}Pu). The purpose of these measurements is to assess the energy delivered by alpha emission from these sources to the lung tissue. A sample (charged progenies attached to aerosols) is collected on filter paper from a known volume of air and placed on the instrument. The discharge rate indicates the alpha energy in MeV l{sup -1} of air per min that is produced by the alpha emitters. The calibration procedure shows that the instrument has an energy sensitivity for alpha particles of 800.5 MeV/scale unit. The range of the readout scale is 30 units. Measurements of alpha contamination in air were made using this instrument in buildings, private homes and in a standard chamber. The value of the radon concentration in this chamber is traceable back to the US Environmental Protection Agency (EPA) and to the National Institute of Standards and Technology (NIST)

  1. Alpha particle density and energy distributions in tandem mirrors using Monte-Carlo techniques

    International Nuclear Information System (INIS)

    We have simulated the alpha thermalization process using a Monte-Carlo technique, in which the alpha guiding center is followed between simulated collisions and Spitzer's collision model is used for the alpha-plasma interaction. Monte-Carlo techniques are used to determine the alpha radial birth position, the alpha particle position at a collision, and the angle scatter and dispersion at a collision. The plasma is modeled as a hot reacting core, surrounded by a cold halo plasma (T approx.50 eV). Alpha orbits that intersect the halo lose 90% of their energy to the halo electrons because of the halo drag, which is ten times greater than the drag in the core. The uneven drag across the alpha orbit also produces an outward, radial, guiding center drift. This drag drift is dependent on the plasma density and temperature radial profiles. We have modeled these profiles and have specifically studied a single-scale-length model, in which the density scale length (r/sub pD/) equals the temperature scale length (r/sub pT/), and a two-scale-length model, in which r/sub pD//r/sub pT/ = 1.1

  2. Experimental light scattering by small particles in Amsterdam and Granada

    NARCIS (Netherlands)

    O. Muñoz; J.W. Hovenier; F. Moreno; D. Guirado; H. Volten

    2009-01-01

    We report on two light scattering instruments located in Amsterdam and Granada, respectively. These instruments enable measuring scattering matrices as functions of the scattering angle of collections of randomly orieneted irregular particles. In the past decades, the experimental setup located in A

  3. Light scattering by nonspherical particles theory, measurements, and applications

    CERN Document Server

    Mishchenko, Michael I; Travis, Larry D

    1999-01-01

    There is hardly a field of science or engineering that does not have some interest in light scattering by small particles. For example, this subject is important to climatology because the energy budget for the Earth's atmosphere is strongly affected by scattering of solar radiation by cloud and aerosol particles, and the whole discipline of remote sensing relies largely on analyzing the parameters of radiation scattered by aerosols, clouds, and precipitation. The scattering of light by spherical particles can be easily computed using the conventional Mie theory. However, most small solid part

  4. Particle detection by a light-scattering technique

    Science.gov (United States)

    Kormanyos, S.; Mastroeni, J.

    1972-01-01

    Instrument measures concentration of small particles in aqueous medium in terms of amount of light scattered and degree to which light transmission is attenuated. Sensitivity to small particles is optimized because both scattered and transmitted illumination levels are detected by photodiodes.

  5. 226Ra determination in phosphogypsum by alpha-particle spectrometry

    International Nuclear Information System (INIS)

    A radiochemical method for 226Ra determination by alpha-particle spectrometry in environmental samples has been developed in our laboratory. The method has been validated by measurements in samples with known concentrations of this radionuclide and it has been applied in studies related to 226Ra behaviour in phosphogypsum (the main by-product of producing phosphoric acid from phosphate rocks). (author)

  6. Discrimination of nuclear recoils from alpha particles with superheated liquids

    CERN Document Server

    Aubin, F; Behnke, E; Beltran, B; Clark, K; Dai, X; Davour, A; Genest, M-H; Giroux, G; Gornea, R; Faust, R; Krauss, C B; Leroy, C; Lessard, L; Levine, I; Levy, C; Martin, J -P; Noble, A J; Morlat, T; Nadeau, P; Piro, M -C; Pospísil, S; Shepherd, T; Sodomka, J; Starinski, N; Stekl, I; Storey, C; Wichoski, U; Zacek, V

    2008-01-01

    The PICASSO collaboration observed for the first time a significant difference between the acoustic signals induced by neutrons and alpha particles in a detector based on superheated liquids. This new effect offers the possibility of improved background suppression and could be especially useful for rare event searches such as dark matter experiments.

  7. Polarization resolved angular optical scattering of aerosol particles

    Science.gov (United States)

    Redding, B.; Pan, Y.; Wang, C.; Videen, G.; Cao, Hui

    2014-05-01

    Real-time detection and identification of bio-aerosol particles are crucial for the protection against chemical and biological agents. The strong elastic light scattering properties of airborne particles provides a natural means for rapid, non-invasive aerosol characterization. Recent theoretical predictions suggested that variations in the polarization dependent angular scattering cross section could provide an efficient means of classifying different airborne particles. In particular, the polarization dependent scattering cross section of aggregate particles is expected to depend on the shape of the primary particles. In order to experimentally validate this prediction, we built a high throughput, sampling system, capable of measuring the polarization resolved angular scattering cross section of individual aerosol particles flowing through an interrogating volume with a single shot of laser pulse. We calibrated the system by comparing the polarization dependent scattering cross section of individual polystyrene spheres with that predicted by Mie theory. We then used the system to study different particles types: Polystyrene aggregates composed 500 nm spheres and Bacillus subtilis (BG, Anthrax simulant) spores composed of elongated 500 nm × 1000 nm cylinder-line particles. We found that the polarization resolved scattering cross section depends on the shape of the constituent elements of the aggregates. This work indicates that the polarization resolved scattering cross section could be used for rapid discrimination between different bio-aerosol particles.

  8. Investigation of advanced materials for fusion alpha particle diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Bonheure, G., E-mail: g.bonheure@fz-juelich.de [Laboratory for Plasma Physics, Association “Euratom-Belgian State”, Royal Military Academy, Avenue de la Renaissance, 30 Kunstherlevinglaan, B-1000 Brussels (Belgium); Van Wassenhove, G. [Laboratory for Plasma Physics, Association “Euratom-Belgian State”, Royal Military Academy, Avenue de la Renaissance, 30 Kunstherlevinglaan, B-1000 Brussels (Belgium); Hult, M.; González de Orduña, R. [Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, B-2440 Geel (Belgium); Strivay, D. [Centre Européen d’Archéométrie, Institut de Physique Nucléaire, Atomique et de Spectroscopie, Université de Liège (Belgium); Vermaercke, P. [SCK-CEN, Boeretang, B-2400 Mol (Belgium); Delvigne, T. [DSI SPRL, 3 rue Mont d’Orcq, Froyennes B-7503 (Belgium); Chene, G.; Delhalle, R. [Centre Européen d’Archéométrie, Institut de Physique Nucléaire, Atomique et de Spectroscopie, Université de Liège (Belgium); Huber, A.; Schweer, B.; Esser, G.; Biel, W.; Neubauer, O. [Forschungszentrum Jülich GmbH, Institut für Plasmaphysik, EURATOM-Assoziation, Trilateral Euregio Cluster, D-52425 Jülich (Germany)

    2013-10-15

    Highlights: ► We examine the feasibility of alpha particle measurements in ITER. ► We test advanced material detectors borrowed from the GERDA neutrino experiment. ► We compare experimental results on TEXTOR tokamak with our detector response model. ► We investigate the detector response in ITER full power D–T plasmas. ► Advanced materials show good signal to noise ratio and alpha particle selectivity. -- Abstract: Fusion alpha particle diagnostics for ITER remain a challenging task. Standard escaping alpha particle detectors in present tokamaks are not applicable to ITER and techniques suitable for fusion reactor conditions need further research and development [1,2]. The activation technique is widely used for the characterization of high fluence rates inside neutron reactors. Tokamak applications of the neutron activation technique are already well developed [3] whereas measuring escaping ions using this technique is a novel fusion plasma diagnostic development. Despite low alpha particle fluence levels in present tokamaks, promising results using activation technique combined with ultra-low level gamma-ray spectrometry [4] were achieved before in JET [5,6]. In this research work, we use new advanced detector materials. The material properties beneficial for alpha induced activation are (i) moderate neutron cross-sections (ii) ultra-high purity which reduces neutron-induced background activation and (iii) isotopic tailoring which increases the activation yield of the measured activation product. Two samples were obtained from GERDA[7], an experiment aimed at measuring the neutrinoless double beta decay in {sup 76}Ge. These samples, made of highly pure (9 N) germanium highly enriched to 87% in isotope Ge-76, were irradiated in real D–D fusion plasma conditions inside the TEXTOR tokamak. Comparison of the calculated and the experimentally measured activity shows good agreement. Compared to previously investigated high temperature ceramic material [8

  9. Pressure control and particle`s motion in ALPHA

    CERN Document Server

    Rudakov, Kirill

    2013-01-01

    The first project was a system to control the pressure of water and gas. The second project was the calculation of tracks of particles. The third project was to make an estimation of mutual inductance.

  10. The Emission of Long-Range Alpha Particles in Fission

    International Nuclear Information System (INIS)

    Fraenkel and Thompson (1964) have shown that the most probable direction of emission of the long-range alpha particles in the spontaneous fission of californium-252 varies with the ratio of the masses of the residual fission fragments. The angle of emission relative to the direction of motion of the lighter fragment increases significantly as the mass of the lighter fragment decreases. Assuming that the alpha particle is emitted at the scission point, these authors conclude that the scission point, in ternary fission, occurs progressively nearer to the lighter fragment as the fragment mass ratio is greater. They point out that this is one of the assumptions underlying the ''geometrical'' model of mass division of Whetstone (1959) and Vladimirski (1957), and is the feature of that model in terms of which the variation of the average number of neutrons with fragment mass in binary fission is successfully explained. They suggest that these various considerations together indicate that the configuration of the scissioning nucleus at (and before) scission in ternary fission closely resembles the corresponding configuration in binary fission. Adopting this last hypothesis in relation to the thermal-neutron-induced fission of uranium-235, the writer (1964) has shown that if the liberation cf the alpha particle occurs at or just after the moment of scission, so that it may be regarded as emitted from a newly formed, but still deformed, fragment then the probability of emission can be deduced from the experiments of Schmitt et al. (1962), if certain further assumptions are made. On the assumption that the alpha particle is derived from the heavy fragment exclusively, it appears that the prob-ability of release from that fragment correlates directly with the average number of secondary neutrons emitted in in binary fission, and also with the energy available for alpha-particle emission from the undeformed (ground state) fragment. There would be no correlation with the energy

  11. A new alpha particle diagnostic using knock-on ion tails

    International Nuclear Information System (INIS)

    We propose a new method of measuring the fast confined ct-particle distribution in a reacting plasma. The presence of ct-particles in a D-T plasma will create a high energy tail on the deuterium and tritium ion energy distributions. A 3.5 MeV alpha can transfer 3.4 MeV to a tritium ion in a single elastic scattering interaction. Calculations of the size of these knock-on tails in tokamaks such as TFTR, JET, and ITER show that it may be possible to measure these tails and provide information on the fast confined alphas. The knock-on tail ions will produce D-T neutrons with energies up to 20.7 MeV, so that D-T neutron spectroscopy can be used to monitor the alpha population. Neutron spectroscopy looks especially attractive for ITER. A collimated array of threshold neutron activation detectors could be used to deduce the confined alpha density profile. Tests of this diagnostic can also be done on TFTR and JET. Existing high energy neutral particle analyzers may allow observation of the ion tails directly via passive and/or active charge exchange

  12. RPL in alpha particle irradiated Ag+-doped phosphate glass

    International Nuclear Information System (INIS)

    The objective of this study is to investigate the emission mechanism of radiophotoluminescence (RPL) in the Ag+-doped phosphate glass (glass dosimeter), which is now used as individual radiation dosimeter, because the emission mechanism of RPL in glass dosimeter has been not fully understood. We have investigated the assignments and characteristics of the X-ray induced color centers in the Ag+-doped phosphate glass up to now (Miyamoto et al., 2010). Optical properties such as optical absorption spectra related with alpha-particles and X-rays irradiation were measured for commercially available glass dosimeter. In this study optical properties such as optical absorption spectrum as a function of alpha-particles and X-rays irradiation were measured for commercially available glass dosimeter. Comparison of the RPL in Ag+-doped phosphate glass irradiated with alpha-particles and X-rays is discussed. - Highlights: • A Yellow and blue emission are included in the RPL of Ag+-doped phosphate glass. • The ratio of yellow and blue emission was different between alpha and X-ray irradiation. • RPL emission intensity increased in an atmosphere below room temperature

  13. Phoswich Detector for Simultaneous Measuring Alpha/beta Particles

    International Nuclear Information System (INIS)

    The new type phoswich detector consisting of the ZnS(Ag) and plastic scintillator for alpha/beta-ray simultaneous counting was developed for monitoring radiological contamination inside pipes. The detection performance was estimated using the PSD (pulse shape discrimination) method as a function of distance between the scintillator and radioactive source. The attenuation of particles traveling through a thin film for preventing the detector from being contaminated was experimentally estimated. It is concluded from our investigation that the phoswich detector developed can provide a sufficient alpha/beta-ray discrimination. The application of a thin film for preventing the detector from being contaminated was proven to be feasible.

  14. Low energy alpha particle spectroscopy using CR-39 detector

    CERN Document Server

    Izerrouken, M; Ilic, R

    1999-01-01

    The possibility of using CR-39 to measure the depth profile of sup 1 sup 0 B in Si is analysed. The measuring technique exploits the sup 1 sup 0 B(n, alpha) sup 7 Li nuclear reaction. For this reason the track parameters (size, optical properties) of low energy alpha-particles (<1.47 MeV) were studied. The results showed that an energy resolution of about 100 keV could be obtained by an appropriate selection of etching conditions. The profile of sup 1 sup 0 B in Si at a depth as small as 1 mu m can be measured.

  15. Alpha particle effects on global MHD modes, and alpha particle transport in ignited tokamaks

    International Nuclear Information System (INIS)

    The high frequency, low mode number toroidicity-induced Alfven eigenmodes (TAE) are shown to be driven unstable primarily by the circulating α-particles through wave-particle resonances. To destabilize the TAE modes, the inverse Landau damping associated with the α-particle pressure gradient free energy must overcome the velocity space Landau damping due to both the α-particles and the core electrons and ions, as well as Alfven continuum damping. Stability criteria are presented for TFTR, CIT, and ITER tokamaks in terms of the α-particle beta βα, the α-particle pressure gradient parameter (ω*/ωA), where ω* is the α-particle diamagnetic drift frequency, and the α-particle velocity (vα/vA) parameter. Typically the volume averaged α-particle beta threshold is on the order of 10-4. Rough estimates of the TAE mode saturation level give δBr/B ∼ 10-3 for typical D-T tokamak operations. Significant α-particle losses are found when the amplitude of the global MHD modes is large, on the order of (δBr/B) ≥ 10-4. For (δBr/B) = 5 x 10-4, the α-particle loss time is appreciably shorter than the α-particle slowing-down time. 13 refs., 1 fig

  16. Alpha particle track coloration in CR-39: Improved observability

    CERN Document Server

    Oezguemues, A

    1999-01-01

    A comparative study of the observability of alpha particle tracks in CR-39 was performed with an optical microscope before and after coloration. The implantation of ink helped in observing the damage zones. At first glance through the microscope, the coloration makes the tracks stand out right away. This coloration is helpful, from the start, in the morphological study of the tracks (size, area, orientation, shape, perimeter). This operation is advantageous in distinguishing the alpha particle tracks from stains or scratches. Thus, the routine counting of the tracks is more easily performed. Consequently, this procedure allowed us: to decrease significantly the standard deviation of the approximate total of the parameters given from the image analysis system (Olympus CUE2); to envision the possibility of reasonably decreasing the etching time in order to limit the loss of information caused by the destruction of the CR-39 during chemical etching and to use a weaker enlarging lens in order to cover a larger fi...

  17. A Novel Experiment to Investigate the Attenuation of Alpha Particles in Air

    Science.gov (United States)

    Andrews, D. G. H.

    2008-01-01

    A simple student experiment investigating dependence on air pressure of the attenuation of alpha particles in air is described. An equation giving the pressure needed to absorb all alpha particles of a given energy is derived from the Bethe-Bloch formula. Results are presented for the attenuation of alpha particles from americium 241 and radium…

  18. Prospects for detecting dark matter particles by elastic scattering

    International Nuclear Information System (INIS)

    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

  19. Producing a compound Nucleus via Inelastic Scattering: The 90Zr(alpha,alpha')90Zr* Case

    Energy Technology Data Exchange (ETDEWEB)

    Escher, J E; Dietrich, F S

    2008-05-23

    In a Surrogate reaction a compound nucleus is produced via a direct reaction (pickup, stripping, or inelastic scattering). For a proper application of the Surrogate approach it is necessary to predict the resulting angular momentum and parity distribution in the compound nucleus. A model for determining these distributions is developed for the case of inelastic alpha scattering off a spherical nucleus. The focus is on obtaining a first, simple description of the direct-reaction process that produces the compound nucleus and on providing the basis for a more complete treatment of the problem. The approximations employed in the present description are discussed and the extensions required for a more rigorous treatment of the problem are outlined. To illustrate the formalism, an application to {sup 90}Zr({alpha},{alpha}{prime}){sup 90}Zr* is presented.

  20. Numerical modelling of multiple scattering between two elastical particles

    DEFF Research Database (Denmark)

    Bjørnø, Irina; Jensen, Leif Bjørnø

    1998-01-01

    question of proximity thresholds for influence of multiple scattering in terms of particle properties like volume fraction, average distance between particles or other related parameters. A few available experimental data indicate a significance of multiple scattering in suspensions where the concentration...... is higher than 20 g/l of sand particles. This paper reports an attempt to illuminate and to solve the proximity threshold question, by an in-depth numerical study of the interaction of ultrasonic signals with two canonically shaped elastic particles. Introductory experimental results seem to create...

  1. Model of alpha particle diffusion in the outer limiter shadow of TFTR

    International Nuclear Information System (INIS)

    A new code, Monte Carlo Collisional Stochastic Orbit Retracing (MCCSOR), has been developed to model the alpha particle loss signal as measured by the outer midplane scintillator detector in TFTR. The shadowing effects due to the outer limiters and the detector itself have been included, along with a pitch angle scattering and stochastic ripple diffusion. Shadowing by the outer limiters has a strong effect on both the magnitude and pitch angle distribution of the calculated loss. There is at least qualitative agreement between the calculated results and the experimental data

  2. Single particle analysis with a 3600 light scattering photometer

    International Nuclear Information System (INIS)

    Light scattering by single spherical homogeneous particles in the diameter range 1 to 20 μm and relative refractive index 1.20 is measured. Particle size of narrowly dispersed populations is determined and a multi-modal dispersion of five components is completely analyzed. A 3600 light scattering photometer for analysis of single particles has been designed and developed. A fluid stream containing single particles intersects a focused laser beam at the primary focal point of an ellipsoidal reflector ring. The light scattered at angles theta = 2.50 to 177.50 at phi = 00 and 1800 is reflected onto a circular array of photodiodes. The ellipsoidal reflector is situated in a chamber filled with fluid matching that of the stream to minimize refracting and reflecting interfaces. The detector array consists of 60 photodiodes each subtending 30 in scattering angle on 60 centers around 3600. 32 measurements on individual particles can be acquired at rates of 500 particles per second. The intensity and angular distribution of light scattered by spherical particles are indicative of size and relative refractive index. Calculations, using Lorenz--Mie theory, of differential scattering patterns integrated over angle corresponding to the detector geometry determined the instrument response to particle size. From this the expected resolution and experimental procedures are determined.Ultimately, the photometer will be utilized for identification and discrimination of biological cells based on the sensitivity of light scattering to size, shape, refractive index differences, internal granularity, and other internal morphology. This study has demonstrated the utility of the photometer and indicates potential for application to light scattering studies of biological cells

  3. Thomson scattering diagnostic analyses to determine the energetic particle distributions in TFTR. Final report

    International Nuclear Information System (INIS)

    Lodestar has been an active participant in the low power Collective Thomson Scattering (CTS) diagnostic at TFTR in collaboration with MIT. Extensive studies were conducted regarding the use of gyrotron scattering as a low cost diagnostic for both energetic ions and alpha particles on TFTR. The numerical scattering code has been improved and compared with similar code developed at JET. The authors have participated and assisted in the CTS experiments through onsite visits and have successfully performed most of the data analysis tasks remotely. Through their analysis on the initial data base accumulated, they are able to understand qualitatively the general features of the anomalous large scattered signal, have proposed an explanation for its generation mechanism, and have suggested a potential new use of CTS as an edge diagnostic

  4. The impact of dust particle morphological details on light scattering

    Science.gov (United States)

    Kemppinen, Osku; Nousiainen, Timo; Lindqvist, Hannakaisa; Jeong, Gi Young

    2016-04-01

    We investigate the impact of dust particle surface roughness and internal structure on light scattering. Starting from digital representation of realistically shaped dust particles, we vary the particle morphology, and perform light scattering simulations to both the original and the modified particles. By mapping the changes in morphology to the changes in scattering, we will get information of how strongly and in which way a particular change affects scattering. All investigations have been done with complex, irregular particle shapes. For surface roughness studies we have kept the particle total volume virtually constant during the roughening process, and the roughness element size small enough to keep the overall shape relatively unchanged. For internal structure studies, the size and the external shape are kept constant. These safety measures help ensure that the effects seen are in fact due to the feature studied. The work is notable for model development, because some models can not include surface roughness, for example. In that case, the people who use such models have to adjust for the fact that the results are inaccurate, and by knowing how surface roughness typically changes the scattering results, the adjustment can be made. As a corollary, if it is shown that a particular feature does not change scattering results in any noticeable way, the model developers can confidently ignore or simplify it.

  5. On the Quantum Mechanical Scattering Statistics of Many Particles

    CERN Document Server

    Dürr, Detlef; Moser, Tilo; Römer, Sarah

    2010-01-01

    The probability of a quantum particle being detected in a given solid angle is determined by the $S$-matrix. The explanation of this fact in time dependent scattering theory is often linked to the quantum flux, since the quantum flux integrated against a (detector-) surface and over a time interval can be viewed as the probability that the particle crosses this surface within the given time interval. Regarding many particle scattering, however, this argument is no longer valid, as each particle arrives at the detector at its own random time. While various treatments of this problem can be envisaged, here we present a straightforward Bohmian analysis of many particle potential scattering from which the $S$-matrix probability emerges in the limit of large distances.

  6. On time dependent scattering theory for identical particles

    International Nuclear Information System (INIS)

    A time-dependent multichannel nonrelativistic quantum scattering theory is established for systems containing identical particles. The symmetry properties of the theory are rooted in certain abstract algebraic relationships between permutations. The formalism of second quantization is thus avoided. Appropriate wave and scattering operators are defined, including those for systems of particles with long range Coulomb interactions. The cluster properties of the scattering operator are rigorously derived. The transition to time-independent theory is made mathematically thus establishing connection with previous time-independent theories. (author)

  7. Gross {alpha}-particle activities in the ground waters in Western Anatolia

    Energy Technology Data Exchange (ETDEWEB)

    Akyil, S.; Erees, F.S.; Olmez, S. [Ege Universitesi, Izmir (Turkey)

    1996-07-01

    The purpose of this study is to present data on gross {alpha}-particle activity, pH and conductivity in the ground waters in Western Anatolia. The gross {alpha}-particle activities in 27 ground water samples were determined by radiochemical carrier-precipitation methods. The gross {alpha}-particle activities of water samples were measured by using a ZnS (Ag) detector system. Measureable {alpha}-particle activity is present in all ground water samples, with one ground water sample having a gross {alpha}-particle activity > 0.55 Bq/L. (Author).

  8. Scattered Lyman-alpha radiation of comet 2012/S1 (ISON) observed by SUMER/SOHO

    Science.gov (United States)

    Curdt, W.; Boehnhardt, H.; Germerott, D.; Schuehle, U.; Solanki, S.; Teriaca, L.; Vincent, J.

    2014-07-01

    During its recent perihelion passage, comet ISON came so close to the Sun that it appeared in the field of view (FOV) of the SUMER spectrometer on SOHO and allowed unique observations at far-UV wavelengths with high spatial and temporal resolution. We report results of these observations completed during the comet's encounter with the Sun on November 28.75, 2013. Our data show the dust tail trailing behind the predicted position of the nucleus seen in Lyman-alpha emission as light from the solar disk that is scattered by micron-sized dust particles. The arrow-shaped tail is offset from the trajectory and not aligned with it. We model the dust emission and dynamics to reproduce the appearance of the tail. We could not detect any signature of cometary gas or plasma around the expected position of the nucleus and conclude that the out-gassing processes must have stopped before the comet entered our FOV. Also the model we used to reproduce the observed dust tail needs a sharp fall-off of the dust production hours before perihelion. We compare the radiance of the dust tail to the Lyman-alpha emission of the disk for an estimate of the dust column density. After observing 18 years mostly solar targets, this was the first time that SUMER completed spectroscopic observations of a comet.

  9. Alpha-particle Measurements Needed for Burning Plasma Experiments

    International Nuclear Information System (INIS)

    The next major step in magnetic fusion studies will be the construction of a burning plasma (BP) experiment where the goals will be to achieve and understand the plasma behavior with the internal heating provided by fusion-generated alpha particles. Two devices with these physics goals have been proposed: the International Thermonuclear Experimental Reactor (ITER) and the Fusion Ignition Research Experiment (FIRE). Extensive conceptual design work for the instrumentation to try to meet the physics demands has been done for these devices, especially ITER. This article provides a new look at the measurements specifically important for understanding the physics aspects of the alpha particles taking into account two significant events. The first is the completion of physics experiments on the Joint European Torus (JET) and the Tokamak Fusion Test Reactor (TFTR) with deuterium-tritium fueling with the first chances to study alpha physics and the second is the realization that relatively compact plasmas, making use of advanced tokamak plasma concepts, are the most probable route to burning plasmas and ultimately a fusion reactor

  10. Alpha-particle Measurements Needed for Burning Plasma Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth M. Young

    2001-09-26

    The next major step in magnetic fusion studies will be the construction of a burning plasma (BP) experiment where the goals will be to achieve and understand the plasma behavior with the internal heating provided by fusion-generated alpha particles. Two devices with these physics goals have been proposed: the International Thermonuclear Experimental Reactor (ITER) and the Fusion Ignition Research Experiment (FIRE). Extensive conceptual design work for the instrumentation to try to meet the physics demands has been done for these devices, especially ITER. This article provides a new look at the measurements specifically important for understanding the physics aspects of the alpha particles taking into account two significant events. The first is the completion of physics experiments on the Joint European Torus (JET) and the Tokamak Fusion Test Reactor (TFTR) with deuterium-tritium fueling with the first chances to study alpha physics and the second is the realization that relatively compact plasmas, making use of advanced tokamak plasma concepts, are the most probable route to burning plasmas and ultimately a fusion reactor.

  11. Investigation of fusion alpha particle ripple losses by means of a kinetic code - alpha particle ripple losses in ITER

    International Nuclear Information System (INIS)

    The discrete nature of a tokamak magnetic system as a consequence of N separate field coils leads to a deviation from axial symmetry and causes additional transport referred to as ripple transport. This loss mechanism whose effectiveness increases with the particle energy must be investigated carefully for fusion alpha particles. The first part of the paper treats the ripple problem by means of a kinetic equation based on a modified Fokker-Planck equation generalized for ripple transport in 1.5-dimensional geometry. For a NET-type tokamak, ripple fluxes have been calculated with the edge ripple δ as a parameter and have been compared to neoclassical and anomalous fluxes. It has been found that particle and power loss fractions are small if the ripple is less than 1%. This results has been confirmed in the second part of the paper that studies the alpha particle ripple losses in ITER by Monte Carlo numerical modelling. Calculations were performed for physics phase and technology phase operation, and it has been shown that the first wall heat deposition profile is very sensitive to the details of plasma equilibrium shape, first wall position and ripple profile. The peak heat load, being small for the reference configuration, may easily be increased up to small changes in the ripple profile and the plasma configuration. (author). 7 refs, 6 figs, 1 tab

  12. Scattering properties of heterogeneous mineral particles with absorbing inclusions

    International Nuclear Information System (INIS)

    We analyze the results of numerically exact computer modeling of scattering and absorption properties of randomly oriented polydisperse heterogeneous particles obtained by placing microscopic absorbing grains randomly on the surfaces of much larger spherical mineral hosts or by imbedding them randomly inside the hosts. These computations are paralleled by those for heterogeneous particles obtained by fully encapsulating fractal-like absorbing clusters in the mineral hosts. All computations are performed using the superposition T-matrix method. In the case of randomly distributed inclusions, the results are compared with the outcome of Lorenz–Mie computations for an external mixture of the mineral hosts and absorbing grains. We conclude that internal aggregation can affect strongly both the integral radiometric and differential scattering characteristics of the heterogeneous particle mixtures. - Highlights: • Scattering and absorption characteristics of heterogeneous particles are studied. • Computations are performed using the superposition T-matrix method. • Internal aggregation modifies optical properties of heterogeneous mixtures

  13. Measurements of DT alpha particle loss near the outer midplane of TFTR

    International Nuclear Information System (INIS)

    Measurements of DT alpha particle loss to the outer midplane region of TFTR have been made using a radially movable scintillator detector. The conclusion from this data is that mechanisms determining the DT alpha loss to the outer midplane are not substantially different from those for DD fusion products. Some of these results are compared with a simplified theoretical model for TF ripple-induced alpha loss, which is expected to be the dominant classical alpha loss mechanism near the outer midplane. An example of plasma-driven MHD-induced alpha particle loss is shown, but no signs of any ''collective'' alpha instability-induced alpha loss have yet been observed

  14. Isoscalar giant dipole resonance in sup 9 sup 0 Zr, sup 1 sup 1 sup 6 Sn, sup 1 sup 4 sup 4 Sm and sup 2 sup 0 sup 8 Pb excited by 240 MeV alpha particle scattering

    CERN Document Server

    Clark, H L; Youngblood, D H; Bachtr, K; Garg, U; Harakeh, M N; Kalantar-Nayestanaki, N

    1999-01-01

    The giant resonance regions of sup 9 sup 0 Zr, sup 1 sup 1 sup 6 Sn, sup 1 sup 4 sup 4 Sm and sup 2 sup 0 sup 8 Pb were investigated using 240 MeV alpha particle scattering at small angles including 0 deg. E1 strengths corresponding to 91+-11%, 89+-10%, 105+-12% and 95+-13% of the isoscalar E1 energy-weighted sum rule were identified between 18<=E sub x<=31 MeV, 16<=E sub x<=30 MeV, 15<=E sub x<=27 MeV and 15<=E sub x<=25 MeV with centroid energies of 24.8+-0.4 MeV, 22.5+-0.3 MeV, 21.6+-0.3 MeV and 19.3+-0.3 MeV and rms widths of 3.2+-0.2 MeV, 3.5+-0.2 MeV, 3.2+-0.2 MeV and 2.5+-0.2 MeV for sup 9 sup 0 Zr, sup 1 sup 1 sup 6 Sn, sup 1 sup 4 sup 4 Sm and sup 2 sup 0 sup 8 Pb, respectively. Parameters obtained for the isoscalar giant monopole resonance, isoscalar giant quadrupole resonance and high energy octupole resonance are in agreement with accepted values.

  15. GaN-based PIN alpha particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Wang Guo [Peking University, Shenzhen Graduate School, Guangdong Shenzhen 518055 (China); Peking University, Beijing, 100871 (China); Fu Kai; Yao Changsheng [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Science, Jiangsu Suzhou 215123 (China); Su Dan; Zhang Guoguang [China Institute of Atomic Energy, Beijing 102413 (China); Wang Jinyan [Peking University, Beijing, 100871 (China); Lu Min, E-mail: mlu2006@sinano.ac.cn [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Science, Jiangsu Suzhou 215123 (China)

    2012-01-21

    GaN-based PIN alpha particle detectors are studied in this article. The electrical properties of detectors have been investigated, such as current-voltage (I-V) and capacitance-voltage (C-V). The reverse current of all detectors is in nA range applied at 30 V, which is suitable for detector operation. The charge collection efficiency (CCE) is measured to be approximately 80% but the energy resolution is calculated to be about 40% mostly because the intrinsic layer is not sufficiently thick enough.

  16. Cluster states and alpha particle condensation in 13C

    International Nuclear Information System (INIS)

    The structure of 13C is studied with the semi-microscopic cluster model, 3α+n orthogonality condition model (OCM). The energy spectra of four 1/2- states and three 1/2+ states up to Ex ~ 13 MeV are successfully reproduced, in particular, three monopole transition strengths are in fair agreement with the observed ones. We discuss the cluster states and alpha particle condensation in the 1/2± states appearing around the 12C+n, 9Be+α and 3α+n thresholds. (author)

  17. GaN-based PIN alpha particle detectors

    International Nuclear Information System (INIS)

    GaN-based PIN alpha particle detectors are studied in this article. The electrical properties of detectors have been investigated, such as current-voltage (I-V) and capacitance-voltage (C-V). The reverse current of all detectors is in nA range applied at 30 V, which is suitable for detector operation. The charge collection efficiency (CCE) is measured to be approximately 80% but the energy resolution is calculated to be about 40% mostly because the intrinsic layer is not sufficiently thick enough.

  18. Alpha particle response characterization of CdZnTe

    Energy Technology Data Exchange (ETDEWEB)

    Amman, Mark; Lee, Julie S.; Luke, Paul N.

    2001-06-28

    The coplanar-grid as well as other electron-only detection techniques are effective in overcoming some of the material problems of CdZnTe and, consequently, have led to efficient gamma-ray detectors with good energy resolution while operating at room temperature. The performance of these detectors is limited by the degree of uniformity in both electron generation and transport. Despite recent progress in the growth of CdZnTe material, small variations in these properties remain a barrier to the widespread success of such detectors. Alpha-particle response characterization of CdZnTe crystals fabricated into simple planar detectors is an effective tool to accurately study electron generation and transport. We have used a finely collimated alpha source to produce two-dimensional maps of detector response. A clear correlation has been observed between the distribution of precipitates near the entrance contact on some crystals and their alpha-response maps. Further studies are ongoing to determine the mechanism for the observed response variations and the reason for the correlation. This paper presents the results of these studies and their relationship to coplanar-grid gamma-ray detector performance.

  19. Alpha particle response characterization of CdZnTe

    International Nuclear Information System (INIS)

    The coplanar-grid as well as other electron-only detection techniques are effective in overcoming some of the material problems of CdZnTe and, consequently, have led to efficient gamma-ray detectors with good energy resolution while operating at room temperature. The performance of these detectors is limited by the degree of uniformity in both electron generation and transport. Despite recent progress in the growth of CdZnTe material, small variations in these properties remain a barrier to the widespread success of such detectors. Alpha-particle response characterization of CdZnTe crystals fabricated into simple planar detectors is an effective tool to accurately study electron generation and transport. We have used a finely collimated alpha source to produce two-dimensional maps of detector response. A clear correlation has been observed between the distribution of precipitates near the entrance contact on some crystals and their alpha-response maps. Further studies are ongoing to determine the mechanism for the observed response variations and the reason for the correlation. This paper presents the results of these studies and their relationship to coplanar-grid gamma-ray detector performance

  20. Particle scattering in nonassociative quantum field theory

    CERN Document Server

    Dzhunushaliev, V D

    1996-01-01

    A model of quantum field theory in which the field operators form a nonassociative algebra is proposed. In such a case, the n-point Green's functions become functionally independent of each other. It is shown that particle interaction in such a theory can be realized by nonlocal virtual objects.

  1. Innershell ionization by fast protons, alpha particles and carbon ions

    International Nuclear Information System (INIS)

    The subject of this thesis is the study of inner-shell excitations of atoms induced by fast charged particle collisions. A new method is described for measuring the spectrum of delta-electrons emitted by 208Pb after excitation by 15 MeV protons or 50 MeV alpha particles. Experimental equipment is described. Results of both experiments are presented and compared with PWBA models and with calculations based on a semi-classical approximation. The small-impact-parameter ionization probabilities obtained are then compared with literature. Also small-impact-parameter measurements done with 100 MeV carbon ions are described. Besides K-shell measurements, the author also presents L-subshell ionization probability results for Pb. An appendix is added in which energy straggling problems in solid targets are treated. (Auth./G.J.P.)

  2. Light scattering by particles in water theoretical and experimental foundations

    CERN Document Server

    Jonasz, Miroslaw

    2007-01-01

    Light scattering-based methods are used to characterize small particles suspended in water in a wide range of disciplines ranging from oceanography, through medicine, to industry. The scope and accuracy of these methods steadily increases with the progress in light scattering research. This book focuses on the theoretical and experimental foundations of the study and modeling of light scattering by particles in water and critically evaluates the key constraints of light scattering models. It begins with a brief review of the relevant theoretical fundamentals of the interaction of light with condensed matter, followed by an extended discussion of the basic optical properties of pure water and seawater and the physical principles that explain them. The book continues with a discussion of key optical features of the pure water/seawater and the most common components of natural waters. In order to clarify and put in focus some of the basic physical principles and most important features of the experimental data o...

  3. Alpha particle track coloration in CR-39: Improved observability

    International Nuclear Information System (INIS)

    A comparative study of the observability of alpha particle tracks in CR-39 was performed with an optical microscope before and after coloration. The implantation of ink helped in observing the damage zones. At first glance through the microscope, the coloration makes the tracks stand out right away. This coloration is helpful, from the start, in the morphological study of the tracks (size, area, orientation, shape, perimeter). This operation is advantageous in distinguishing the alpha particle tracks from stains or scratches. Thus, the routine counting of the tracks is more easily performed. Consequently, this procedure allowed us: to decrease significantly the standard deviation of the approximate total of the parameters given from the image analysis system (Olympus CUE2); to envision the possibility of reasonably decreasing the etching time in order to limit the loss of information caused by the destruction of the CR-39 during chemical etching and to use a weaker enlarging lens in order to cover a larger field of observation for the counting operations

  4. Detection of alpha particles using DNA/Al Schottky junctions

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ta' ii, Hassan Maktuff Jaber, E-mail: hassankirkukly@gmail.com, E-mail: vengadeshp@um.edu.my [Low Dimensional Materials Research Centre (LDMRC), 50603 Kuala Lumpur (Malaysia); Department of Physics, Faculty of Science, University of Al-Muthana, Al-Muthana 66001 (Iraq); Periasamy, Vengadesh, E-mail: hassankirkukly@gmail.com, E-mail: vengadeshp@um.edu.my [Low Dimensional Materials Research Centre (LDMRC), 50603 Kuala Lumpur (Malaysia); Amin, Yusoff Mohd [Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-09-21

    Deoxyribonucleic acid or DNA can be utilized in an organic-metallic rectifying structure to detect radiation, especially alpha particles. This has become much more important in recent years due to crucial environmental detection needs in both peace and war. In this work, we fabricated an aluminum (Al)/DNA/Al structure and generated current–voltage characteristics upon exposure to alpha radiation. Two models were utilized to investigate these current profiles; the standard conventional thermionic emission model and Cheung and Cheung's method. Using these models, the barrier height, Richardson constant, ideality factor and series resistance of the metal-DNA-metal structure were analyzed in real time. The barrier height, Φ value calculated using the conventional method for non-radiated structure was 0.7149 eV, increasing to 0.7367 eV after 4 min of radiation. Barrier height values were observed to increase after 20, 30 and 40 min of radiation, except for 6, 8, and 10 min, which registered a decrease of about 0.67 eV. This was in comparison using Cheung and Cheung's method, which registered 0.6983 eV and 0.7528 eV for the non-radiated and 2 min of radiation, respectively. The barrier height values, meanwhile, were observed to decrease after 4 (0.61 eV) to 40 min (0.6945 eV). The study shows that conventional thermionic emission model could be practically utilized for estimating the diode parameters including the effect of series resistance. These changes in the electronic properties of the Al/DNA/Al junctions could therefore be utilized in the manufacture of sensitive alpha particle sensors.

  5. Detection of alpha particles using DNA/Al Schottky junctions

    International Nuclear Information System (INIS)

    Deoxyribonucleic acid or DNA can be utilized in an organic-metallic rectifying structure to detect radiation, especially alpha particles. This has become much more important in recent years due to crucial environmental detection needs in both peace and war. In this work, we fabricated an aluminum (Al)/DNA/Al structure and generated current–voltage characteristics upon exposure to alpha radiation. Two models were utilized to investigate these current profiles; the standard conventional thermionic emission model and Cheung and Cheung's method. Using these models, the barrier height, Richardson constant, ideality factor and series resistance of the metal-DNA-metal structure were analyzed in real time. The barrier height, Φ value calculated using the conventional method for non-radiated structure was 0.7149 eV, increasing to 0.7367 eV after 4 min of radiation. Barrier height values were observed to increase after 20, 30 and 40 min of radiation, except for 6, 8, and 10 min, which registered a decrease of about 0.67 eV. This was in comparison using Cheung and Cheung's method, which registered 0.6983 eV and 0.7528 eV for the non-radiated and 2 min of radiation, respectively. The barrier height values, meanwhile, were observed to decrease after 4 (0.61 eV) to 40 min (0.6945 eV). The study shows that conventional thermionic emission model could be practically utilized for estimating the diode parameters including the effect of series resistance. These changes in the electronic properties of the Al/DNA/Al junctions could therefore be utilized in the manufacture of sensitive alpha particle sensors

  6. Detection of alpha particles using DNA/Al Schottky junctions

    Science.gov (United States)

    Al-Ta'ii, Hassan Maktuff Jaber; Periasamy, Vengadesh; Amin, Yusoff Mohd

    2015-09-01

    Deoxyribonucleic acid or DNA can be utilized in an organic-metallic rectifying structure to detect radiation, especially alpha particles. This has become much more important in recent years due to crucial environmental detection needs in both peace and war. In this work, we fabricated an aluminum (Al)/DNA/Al structure and generated current-voltage characteristics upon exposure to alpha radiation. Two models were utilized to investigate these current profiles; the standard conventional thermionic emission model and Cheung and Cheung's method. Using these models, the barrier height, Richardson constant, ideality factor and series resistance of the metal-DNA-metal structure were analyzed in real time. The barrier height, Φ value calculated using the conventional method for non-radiated structure was 0.7149 eV, increasing to 0.7367 eV after 4 min of radiation. Barrier height values were observed to increase after 20, 30 and 40 min of radiation, except for 6, 8, and 10 min, which registered a decrease of about 0.67 eV. This was in comparison using Cheung and Cheung's method, which registered 0.6983 eV and 0.7528 eV for the non-radiated and 2 min of radiation, respectively. The barrier height values, meanwhile, were observed to decrease after 4 (0.61 eV) to 40 min (0.6945 eV). The study shows that conventional thermionic emission model could be practically utilized for estimating the diode parameters including the effect of series resistance. These changes in the electronic properties of the Al/DNA/Al junctions could therefore be utilized in the manufacture of sensitive alpha particle sensors.

  7. Questions of the optical potential for alpha-particles at low energies

    International Nuclear Information System (INIS)

    Among the high-priority elements for the accelerator driven systems (ADS) and fusion-reactor projects are also Zr, Mo and Li, so that the corresponding nuclear data for nucleon-, deuteron-, and α-particle interactions are of actual interest for neutron production, activation, heating, shielding requirements, and material damage estimation as well as radioactive waste transmutation projects. By using advanced nuclear models that account for details of nuclear structure and the quantum nature of the nuclear scattering, significant gains in accuracy can be achieved below 150 MeV, where intranuclear cascade calculations become less accurate. It is why this work reports on the progress of the analysis of optical potentials for nucleons, deuterons and α-particles on isotopes of these elements, and corresponding reaction cross sections calculations. The elastic-scattering angular distributions measured at deuteron energies between 3 and 50 MeV on the target nucleus 6Li, and between 1 and 14.7 MeV for the target nucleus 7Li have been thus analyzed by using the computer codes SCAT2 for pure elastic scattering processes and FRESCO for the coupled reaction channels for taking into account the effects of the elastic and inelastic alpha transfer in the d+6Li interaction. The good overall agreement obtained with the experimental data for both 6,7Li target nuclei from 1 to 50 MeV has finally proved suitable optical model potentials (OMPs). Within the double folding formalism of the alpha-nucleus optical potential, used previously for a semi-microscopic analysis of the alpha-particle elastic scattering on A∼100 nuclei at energies below 32 MeV, effects due to changes of the nuclear density at a finite temperature are considered. Parameterizations of the double-folding (DF) real potential as well as of a regional phenomenological potential have been used in the study of the (n,α) reaction cross sections for the target nuclei 92,95,98,100Mo. Taking the microscopic DF potentials

  8. Charged particle scattering on two infinite cylindrical solenoids

    International Nuclear Information System (INIS)

    Charged particle scattering on two infinitely parallel cylindrical solenoids with similar by value and inverse by the sign magnetic fields is considered. Scattering amplitude is calculated in the 1st Born and high energy approximations. In both cases the differential cross section is nonsingular and the integral one - finite. Specific examples demonstrating that in one and the same multi-connection space under nontrivial vector-potentials and unambigous wave functions Aharonov-Bohm (AB) effect can exist but it can be absent as well. It is shown that an alternative AB effect interpretation as scattering in magnetic field leakages meets sufficient difficulties

  9. Surface plasmon polaritons scattering by subwavelength dielectric particles

    CERN Document Server

    Aporvari, Mehdi Shafiei

    2015-01-01

    Surface plasmon polaritons scattering from subwavelength dielectric particles is investigated using finite difference time domain method. It is shown that coupling an incident surface plasmon polariton to inter-cavity modes of the particle can dramatically changes transmitted fields and plasmon-induced forces. In particular, both transmission and optical forces are highly sensitive to the particle size that is related to the excitation of whispering gallery modes or standing-wave modes depending on the particle shape and size. This features might have potential sensing applications.

  10. A Feasibility Study of a Portable Alpha Particle Spectrometer

    International Nuclear Information System (INIS)

    Alpha spectroscopy is widely used for detecting undeclared nuclear facilities, activities, and materials. Due to the heavy equipment required to carry out this technique, its applications is limited. With the goal of quickly and efficiently responding to undeclared nuclear facilities, activities, and materials, the present authors have designed and built a portable α-particle spectrometer. This study was conducted in order to develop a new portable α-particle spectrometer with the purpose of detecting undeclared nuclear facilities, activities, and materials on site quickly and efficiently. All heavy and large components, which are typically required for a laboratory such as a αparticle spectrometry system, were minimized and placed in a small container with a weight of 14 kg and a size of 30 cm x 30 cm x 30 cm. In the feasibility study, the calculated enrichment values of 235U obtained from the portable α-particle spectrometer were 1.868 % and 3.083 %, similar to the results from a commercial spectrometry system used in laboratories, 2.049 % and 3.253 %. These differences were possibly caused by different channel setups for each system

  11. Scattering of particles by radiation fields: a comparative analysis

    CERN Document Server

    Bini, Donato; Haney, Maria; Jantzen, Robert T

    2014-01-01

    The features of the scattering of massive neutral particles propagating in the field of a gravitational plane wave are compared with those characterizing their interaction with an electromagnetic radiation field. The motion is geodesic in the former case, whereas in the case of an electromagnetic pulse it is accelerated by the radiation field filling the associated spacetime region. The interaction with the radiation field is modeled by a force term entering the equations of motion proportional to the 4-momentum density of radiation observed in the particle's rest frame. The corresponding classical scattering cross sections are evaluated too.

  12. Photothermal imaging of nanometer-sized metal particles among scatterers.

    Science.gov (United States)

    Boyer, David; Tamarat, Philippe; Maali, Abdelhamid; Lounis, Brahim; Orrit, Michel

    2002-08-16

    Ambient optical detection of labeled molecules is limited for fluorescent dyes by photobleaching and for semiconducting nanoparticles by "blinking" effects. Because nanometer-sized metal particles do not optically bleach, they may be useful optical labels if suitable detection signals can be found. We demonstrate far-field optical detection of gold colloids down to diameters of 2.5 nanometers with a photothermal method that combines high-frequency modulation and polarization interference contrast. The photothermal image is immune to the effects of scattering background, which limits particle imaging through Rayleigh scattering to diameters larger than 40 nanometers. PMID:12183624

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

    Science.gov (United States)

    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.

  14. Scattering of twisted particles: extension to wave packets

    CERN Document Server

    Ivanov, I P

    2011-01-01

    High-energy photons and other particles carrying non-zero orbital angular momentum (OAM) emerge as a new tool in high-energy physics. Generation of energetic photons with non-zero OAM (twisted photons) in Compton backscattering seems feasible with today's technology, and collisions of high-energy twisted states can offer a new look at particle properties and interactions. A theoretical description of twisted particle scattering developed previously treated them as pure Bessel states. Here we develop further this formalism by incoprorating two additional important features. First, we treat the initial OAM state as a wave packet of a finite transverse size rather than a pure Bessel state. This realistic assumption allows us to resolve the existing controversy between two theoretical analyses for a non-backward scattering. Second, we describe the final twisted particle in terms of the OAM projection on its average direction of propagation (which we call the "orbital helicity") rather than the OAM projection on t...

  15. Alpha particle losses from Tokamak Fusion Test Reactor deuterium-tritium plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Darrow, D.S.; Zweben, S.J. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Batha, S. [Fusion Physics and Technology, Torrance, CA (United States)

    1996-01-01

    Because alpha particle losses can have a significant influence on tokamak reactor viability, the loss of deuterium-tritium alpha particles from the Tokamak Fusion Test Reactor (TFTR) has been measured under a wide range of conditions. In TFTR, first orbit loss and stochastic toroidal field ripple diffusion are always present. Other losses can arise due to magnetohydrodynamic instabilities or due to waves in the ion cyclotron range of frequencies. No alpha particle losses have yet been seen due to collective instabilities driven by alphas. Ion Bernstein waves can drive large losses of fast ions from TFTR, and details of those losses support one element of the alpha energy channeling scenario.

  16. Alpha particle losses from Tokamak Fusion Test Reactor deuterium-tritium plasmas

    International Nuclear Information System (INIS)

    Because alpha particle losses can have a significant influence on tokamak reactor viability, the loss of deuterium-tritium alpha particles from the Tokamak Fusion Test Reactor (TFTR) has been measured under a wide range of conditions. In TFTR, first orbit loss and stochastic toroidal field ripple diffusion are always present. Other losses can arise due to magnetohydrodynamic instabilities or due to waves in the ion cyclotron range of frequencies. No alpha particle losses have yet been seen due to collective instabilities driven by alphas. Ion Bernstein waves can drive large losses of fast ions from TFTR, and details of those losses support one element of the alpha energy channeling scenario

  17. Alpha scattering and capture reactions in the A = 7 system at low energies

    CERN Document Server

    Mohr, P J; Zwiebel, R; Staudt, G; Krauss, H; Oberhummer, Heinz; Denker, A; Hammer, J W; Wolf, G

    1993-01-01

    Differential cross sections for $^3$He-$\\alpha$ scattering were measured in the energy range up to 3 MeV. These data together with other available experimental results for $^3$He $+ \\alpha$ and $^3$H $+ \\alpha$ scattering were analyzed in the framework of the optical model using double-folded potentials. The optical potentials obtained were used to calculate the astrophysical S-factors of the capture reactions $^3$He$(\\alpha,\\gamma)^7$Be and $^3$H$(\\alpha,\\gamma)^7$Li, and the branching ratios for the transitions into the two final $^7$Be and $^7$Li bound states, respectively. For $^3$He$(\\alpha,\\gamma)^7$Be excellent agreement between calculated and experimental data is obtained. For $^3$H$(\\alpha,\\gamma)^7$Li a $S(0)$ value has been found which is a factor of about 1.5 larger than the adopted value. For both capture reactions a similar branching ratio of $R = \\sigma(\\gamma_1)/\\sigma(\\gamma_0) \\approx 0.43$ has been obtained.

  18. Testing particle exchange in p-p scattering

    Science.gov (United States)

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

    1985-03-01

    A recently proposed polarization test for one-particle exchange mechanisms of a given parity is applied to elastic proton-proton scattering at 300, 579, 800 MeV and at 6 GeV/ c. At the three lower energies, as one would expect, no such dominance is found, but at 6 GeV/ c a marked dominance by one-particle exchanges of natural parity appears in the data.

  19. Testing particle exchange in p-p scattering

    International Nuclear Information System (INIS)

    A recently proposed polarization test for one-particle exchange mechanisms of a given parity is applied to elastic proton-proton scattering at 300, 579, 800 MeV and at 6 GeV/c. At the three lower energies, as one would expect, no such dominance is found, but at 6 GeV/c a marked dominance by one-particle exchanges of natural parity appears in the data. (orig.)

  20. Effect of dust particle polarization on scattering processes in complex plasmas

    International Nuclear Information System (INIS)

    Screened interaction potentials in dusty plasmas taking into account the polarization of dust particles have been obtained. On the basis of screened potentials scattering processes for ion-dust particle and dust particle-dust particle pairs have been studied. In particular, the scattering cross section is considered. The scattering processes for which the dust grain polarization is unimportant have been found. The effect of zero angle dust particle-dust particle scattering is predicted

  1. Study on cytotoxicities induced by alpha particle irradiation combined with NNK treatment

    International Nuclear Information System (INIS)

    Objective: To investigate cytotoxicities of alpha-particle irradiation combined with NNK treatment. Methods: Exponentially growing immortalized human bronchial epithelial cells were divided into normal control group (NC), alpha particle irradiation group (α), NNK administration group (NNK), NNK administration (100 μg/ml) followed by alpha particle irradiation group (NNK + α), and alphaparticle irradiation followed by NNK administration (100 μg/ml) group (α + NNK). Cell survival fractions were measured by cloning rate of low-density plating cell. Ethidium bromide and 2', 7'-dichlorofluorescein, fluorescent products of the membrane-permeable dyes hydroethine and 2', 7'-dichloroflurescindiacetate were used to monitor the inarticulate reactive oxygen species (ROS) . Damage to membrane permeability was evaluated through testing LDH activity in medium. Results: In the groups exposed to both alpha particles and NNK, the survival rates were significantly lower than that of the groups administrated with the same dose of alpha particles or NNK alone. The levels of intracellular ROS and the activity of LDH in medium were significantly higher than that of the groups administrated with the same dose of alpha particles or NNK alone. Subtracted the NNK effect, the survival rates of the groups received both alpha particle irradiation and NNK treatment were significantly lower than that of alpha particle irradiated only group. However, the intracellular ROS level and the activity of LDH in medium were significantly higher than that of alpha-particle irradiated only group. In addition, the survival rates of the cells in groups exposed to alpha particle irradiation followed by NNK administration were significantly lower than that of cells treated with NNK administration followed by alpha particle irradiation. Conclusions: Alpha particle irradiation and NNK administration had synergisticity in cytotoxicity, and furthermore different schedules of the administration resulted in

  2. Influence of Magnolol on the bystander effect induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W.; Law, Y.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, the influence of Magnolol on the bystander effect in alpha-particle irradiated Chinese hamster ovary (CHO) cells was examined. The bystander effect was studied through medium transfer experiments. Cytokinesis-block micronucleus (CBMN) assay was performed to quantify the chromosome damage induced by alpha-particle irradiation. Our results showed that the alpha-particle induced micronuclei (MN) frequencies were suppressed with the presence of Magnolol.

  3. A novel experiment to investigate the attenuation of alpha particles in air

    International Nuclear Information System (INIS)

    A simple student experiment investigating dependence on air pressure of the attenuation of alpha particles in air is described. An equation giving the pressure needed to absorb all alpha particles of a given energy is derived from the Bethe-Bloch formula. Results are presented for the attenuation of alpha particles from americium 241 and radium 226. The experimental results are in close agreement with the theoretical predictions

  4. New alpha particle counter based on micro-pixel avalanche photodiode

    International Nuclear Information System (INIS)

    Full text : The main goal of this work is study of possibility to detect alpha particles with micro-pixel avalanche photodiode which has very thin active volume. The obtained results show that alpha detectors based on the micro-pixel avalanche photodiodes can be used as alpha particle counter in many experiments : public security, radioactive contamination monitoring in various environments and detection of charged particles from nuclear reactions

  5. Alpha particles (citations from the International Aerospace Abstracts data base). Report for 1974-July 1979

    International Nuclear Information System (INIS)

    This bibliography of citations to the international literature covers various aspects of alpha particles as applied to controlled fusion devices, solar activity, and geomagnetically trapped particles. Included are articles concerning Tokamak devices, plasma heating and control, plasma-particle interactions, solar particles, solar wind, solar flares, energy spectra, and magnetohydrodynamic stability. Articles concerning effects of alpha particles on different kinds of devices are also included

  6. Stimulated Raman scattering in the presence of trapped particle instability

    Czech Academy of Sciences Publication Activity Database

    Mašek, Martin; Rohlena, Karel

    2008-01-01

    Roč. 13, - (2008), s. 125-129. ISSN 1007-5704 R&D Projects: GA ČR GA202/05/2475 Institutional research plan: CEZ:AV0Z10100523 Keywords : Vlasov equation * stimulated Raman scattering * trapped particle instability * electrostatic quasi -mode Subject RIV: BH - Optics, Masers, Lasers

  7. Control of alpha particle transport by spatially inhomogeneous ion cyclotron resonance heating

    International Nuclear Information System (INIS)

    Control of the radial alpha particle transport by using Ion Cyclotron Range of Frequency waves is investigated in a large-aspect-ratio tokamak geometry. It is shown that spatially inhomogeneous ICRF-wave energy with properly selected frequencies and wave numbers can induce fast convective transport of alpha particles at the speed of order υalpha ∼ (PRF/nαε0) ρp, where PRF is the ICRF-wave power density, nα is the alpha density, ε0 is the alpha birth energy, and ρp is the poloidal gyroradius of alpha particles at the birth energy. Application to ITER plasmas is studied and possible antenna designs to control alpha particle flux are discussed. 8 refs., 3 figs

  8. Controlling the scattering properties of thin, particle-doped coatings

    Science.gov (United States)

    Rogers, William; Corbett, Madeleine; Manoharan, Vinothan

    2013-03-01

    Coatings and thin films of small particles suspended in a matrix possess optical properties that are important in several industries from cosmetics and paints to polymer composites. Many of the most interesting applications require coatings that produce several bulk effects simultaneously, but it is often difficult to rationally formulate materials with these desired optical properties. Here, we focus on the specific challenge of designing a thin colloidal film that maximizes both diffuse and total hemispherical transmission. We demonstrate that these bulk optical properties follow a simple scaling with two microscopic length scales: the scattering and transport mean free paths. Using these length scales and Mie scattering calculations, we generate basic design rules that relate scattering at the single particle level to the film's bulk optical properties. These ideas will be useful in the rational design of future optically active coatings.

  9. New features of nuclear excitation by α particles scattering

    International Nuclear Information System (INIS)

    Inelastic scattering of medium energy a particles by nuclei is known to excite preferentially levels of collective character. We have studied the scattering of isotopically enriched targets of Ca, Fe, Ni, Cu, Zn. In part I, we discuss the theoretical features of the interaction. In part II, we describe the experimental procedure. Results are presented and analysed in part III. α particles scattering by Ca40 is showed to excite preferentially odd parity levels. In odd nuclei we have observed multiplets due to the coupling of the odd nucleon with the even-even core vibrations. For even-even nuclei, a few levels are excited with lower cross-sections between the well-known first 2+ and 3- states. Some could be members of the two phonon quadrupole excitation and involve a double nuclear excitation process. (author)

  10. New concept for a wall detector for alpha particles

    International Nuclear Information System (INIS)

    A new concept for a wall-mounted detector is described here that would measure D-T alpha flux and corresponding pitch angle distribution in tokamaks (or related toroidal devices). The sensing element is a conical Micro Channel Ring (MCR) coated with 1 to 2μ of ZnS scintillator (or possibly ZnO). The collimation of the α particles is provided by two circumferential slots at the wall surface. The alpha scintillation events on the MCR are transferred through the ring channels and coupled fiber optics bundle to an external processor. From the magnetic field vector at a given point on the device wall, a certain relation can be set up between the α-induced scintillation position on the MCR and its original pitch angle (i.e., the angle between the α emission from the fusion reaction and the magnetic field vector) which is equal to the local pitch angle since the wall α flux is dominated by prompt losses

  11. Model of cell response to {\\alpha}-particle radiation

    CERN Document Server

    Liu, Longjian

    2012-01-01

    Starting from a general equation for organism (or cell system) growth and attributing additional cell death rate (besides the natural rate) to therapy, we derive an equation for cell response to {\\alpha} radiation. Different from previous models that are based on statistical theory, the present model connects the consequence of radiation with the growth process of a biosystem and each variable or parameter has meaning regarding the cell evolving process. We apply this equation to model the dose response for {\\alpha}-particle radiation. It interprets the results of both high and low linear energy transfer (LET) radiations. When LET is high, the additional death rate is a constant, which implies that the localized cells are damaged immediately and the additional death rate is proportional to the number of cells present. While at low LET, the additional death rate includes a constant term and a linear term of radiation dose, implying that the damage to some cell nuclei has a time accumulating effect. This model ...

  12. A measurement of alpha-alpha elastic scattering at the CERN ISR

    International Nuclear Information System (INIS)

    We present measurements of the αα elastic scattering differential cross section at √s=126 GeV in the range 0.052. The data give an improved definition of the first cross section minimum at vertical stroketvertical stroke=0.098 (GeV/c)2 and are consistent with theoretical models of nucleus-nucleus scattering. The αα total cross section obtained by extrapolation to the optical point is 280+-70 mb. (orig.)

  13. Detection of lost alpha particle by concealed lost ion probe

    International Nuclear Information System (INIS)

    Full orbit-following calculation is performed for the final orbit of the lost alpha particles, showing some orbits escaping from the last closed flux surface could be detected by a concealed lost ion probe (CLIP) installed under the shadow of the original first wall surface. While both passing and trapped orbits hit the same wall panel, detecting a trapped orbit by the CLIP is easier than detecting passing orbits. Whether the final orbit is detected or not is determined by the position of the reflection point. The CLIP successfully detects the trapped orbits, which are reflected before they hit to a first wall. Then the pitch angles of the orbits at the CLIP are close to and smaller than 90 deg. Optimization of the position of the CLIP in terms of broader detection window is investigated.

  14. Particle-like wave packets in complex scattering systems

    CERN Document Server

    Gérardin, Benoît; Ambichl, Philipp; Prada, Claire; Rotter, Stefan; Aubry, Alexandre

    2016-01-01

    A wave packet undergoes a strong spatial and temporal dispersion while propagating through a complex medium. This wave scattering is often seen as a nightmare in wave physics whether it be for focusing, imaging or communication purposes. Controlling wave propagation through complex systems is thus of fundamental interest in many areas, ranging from optics or acoustics to medical imaging or telecommunications. Here, we study the propagation of elastic waves in a cavity and a disordered waveguide by means of laser interferometry. We demonstrate how the direct experimental access to the information stored in the scattering matrix of these systems allows us to selectively excite scattering states and wave packets that travel along individual classical trajectories. Due to their limited dispersion, these particle-like scattering states will be crucially relevant for all applications involving selective wave focusing and efficient information transfer through complex media.

  15. Anomalous loss of DT alpha particles in the Tokamak Fusion Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, H.W.

    1997-09-01

    An escaping alpha collector probe has been developed for TFTR`s DT phase. Energy distributions of escaping alphas have been determined by measuring the range of {alpha}-particles implanted into nickel foils located within the alpha collector. Results at 1.0 MA of plasma current are in good agreement with predictions for first orbit alpha loss. Results at 1.8 MA, however, show a significant anomalous loss of partially thermalized alphas (in addition to the expected first orbit loss), which is not observed with the lost alpha scintillator detectors in DT plasmas, but does resemble the anomalous delayed loss seen in DD plasmas. None of the candidate explanations proposed thus far are fully consistent with the anomalous loss observations. An experiment designed to study the effect of plasma major radius shifts on {alpha}-particle loss has led to a better understanding of {alpha}-particle dynamics in tokamaks. Intuitively, one might suppose that confined marginally passing {alpha}-particles forced to move toward higher magnetic field during an inward major radius shift (i.e., compression) would mirror and become trapped particles, leading to increased alpha loss. Such an effect was looked for during the shift experiment, however, no significant changes in alpha loss to the 90{degree} lost alpha scintillator detector were observed during the shifts. It is calculated that the energy gained by an {alpha}-particle during the inward shift is sufficient to explain this result. However, an unexpected loss of partially thermalized {alpha}-particles near the passing/trapped boundary was observed to occur between inward and outward shifts at an intermediate value of plasma current (1.4 MA). This anomalous loss feature is not yet understood.

  16. K-alpha conversion efficiency measurments for x-ray scattering in inertial confinement fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kritcher, A L; Neumayer, P; Urry, M K; Robey, H; Niemann, C; Landen, O L; Morse, E; Glenzer, S H

    2006-11-21

    The conversion efficiency of ultra short-pulse laser radiation to K-{alpha} x-rays has been measured for various chlorine-containing targets to be used as x-ray scattering probes of dense plasmas. The spectral and temporal properties of these sources will allow spectrally-resolved x-ray scattering probing with picosecond temporal resolution required for measuring the plasma conditions in inertial confinement fusion experiments. Simulations of x-ray scattering spectra from these plasmas show that fuel capsule density, capsule ablator density, and shock timing information may be inferred.

  17. Optical scattering (TAOS) by tire debris particles: preliminary results

    Science.gov (United States)

    Crosta, Giovanni F.; Camatini, Marina C.; Zomer, Simeone; Holler, Stephen; Pan, Yongle; Bhaskara, Praveena; Muangchareon, Pongphisanu; Sung, Changmo; Cencetti, Simone; Regazzoni, Claudia

    2001-03-01

    Tire debris particles from low severity laboratory wear tests have been investigated by the TAOS optical scattering facility at Yale University. The incident wavelength is 532 nm. After the TAOS event some particle samples have been imaged by a scanning electron microscope and microanalyzed. The TAOS intensity patterns recorded within a solid angle in the backward sector have been processed by cluster analysis and compared with the patterns computed by a T-matrix code. Preliminary agreement has been found between TAOS data and the particle models (size, shape, refractive index). The purpose of the investigation is to obtain signatures of the material, based on its TAOS pattern.

  18. Scattered Lyman-alpha radiation of comet 2012/S1 (ISON) observed by SUMER/SOHO

    CERN Document Server

    Curdt, W; Vincent, J -B; Solanki, S K; Schühle, U; Teriaca, L

    2014-01-01

    During its sungrazing perihelion passage, comet ISON appeared in the field of view of the SUMER spectrometer and allowed unique observations at far-ultraviolet wavelengths with high spatial and temporal resolution. We report results of these observations completed on November 28, 2013, when the comet was only 2.82 R_Sun away from the Sun. Our data show the arrow-shaped dust tail in Ly-$\\alpha$ emission trailing behind the predicted position of the nucleus, but offset from the trajectory. We interpret the emission as sunlight that is scattered at micron-sized dust particles. We modeled the dust emission and dynamics to reproduce the appearance of the tail. We were unable to detect any signature of cometary gas or plasma around the expected position of the nucleus and conclude that the outgassing processes must have stopped before the observation started. Moreover, the model we used to reproduce the observed dust tail needs a sharp fall-off of the dust production hours before perihelion transit. We compare the ...

  19. Scattering Equations: Real Solutions and Particles on a Line

    CERN Document Server

    Cachazo, Freddy; Zhang, Guojun

    2016-01-01

    We find $n(n-3)/2$-dimensional regions of the space of kinematic invariants, where all the solutions to the scattering equations (the core of the CHY formulation of amplitudes) for $n$ massless particles are real. On these regions, the scattering equations are equivalent to the problem of finding stationary points of $n-3$ mutually repelling particles on a finite real interval with appropriate boundary conditions. This identification directly implies that for each of the $(n-3)!$ possible orderings of the $n-3$ particles on the interval, there exists one stable stationary point. Furthermore, restricting to four dimensions, we find that the separation of the solutions into $k\\in \\{2,3,\\ldots ,n-2\\}$ sectors naturally matches that of permutations of $n-3$ labels into those with $k-2$ descents. This leads to a physical realization of the combinatorial meaning of the Eulerian numbers.

  20. Chromosomal aberrations induced by alpha particles; Aberraciones cromosomicas inducidas por particulas {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero C, C.; Brena V, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: cgc@nuclear.inin.mx

    2005-07-01

    The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

  1. Scattering by ensembles of small particles experiment, theory and application

    International Nuclear Information System (INIS)

    A hypothetical selfconsistent picture of evolution of prestellar interstellar dust through a comet phase leades to predictions about the composition of the circum-solar dust cloud. Scattering properties of thus resulting conglomerates with a bird's-nest type of structure are investigated using a micro-wave analogue technique. Approximate theoretical methods of general interest are developed which compared favorably with the experimental results. The principal features of scattering of visible radiation by zodiacal light particles are reasonably reproduced. A component which is suggestive of β-meteoroids is also predicted. (author)

  2. Scattering theory relevant to the linear transport of particle swarms

    International Nuclear Information System (INIS)

    The long-time behavior of the velocity distribution of a spatially uniform diluted guest population of charged particles moving within a host medium under the influence of a D.C. electric field is studied within the framework of scattering theory. The authors prove the existence of wave and scattering operators for a simplified one-dimensional model of the linearized Boltzmann equation. The theory is applied to the study of the long-term behavior of electrons and the occurrence of traveling waves in runaway processes

  3. Anomalous Loss of DT Alpha Particles in the Tokamak Fusion Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Hans W.

    1997-06-01

    Princeton's Tokamak Fusion Test Reactor (TFTR) is the first experimental fusion device to routinely use tritium to study the deuterium-tritium (DT) fusion reaction,allowing the first systematic study of DT alpha particles in tokamak plasmas. A crucial aspect of alpha-particle physics is the fraction of alphas that escape from the plasma, particularly since these energetic particles can do severe damage to the first wall of a reactor. An escaping alpha collector probe has been developed for TFTR's DT phase. Energy distributions of escaping alphas have been determined by measuring the range of alpha-particles implanted into nickel foils located within the alpha collector. Results at 1.0 MA of plasma current are in good agreement with predictions for first orbit alpha loss. Results at 1.8 MA, however, show a significant anomalous loss of partially thermalized alphas (in addition to the expected first orbit loss), which is not observed with the lost alpha scintillator detectors in DT plasmas, but does resemble the anomalous "delayed" loss seen in DD plasmas. None of the candidate explanations proposed thus far are fully consistent with the anomalous loss observations. An experiment designed to study the effect of plasma major radius shifts on alpha-particle loss has led to a better understanding of alpha-particle dynamics in tokamaks. Intuitively, one might suppose that confined marginally passing alpha-particles forced to move toward higher magnetic field during an inward major radius shift (i.e. compression) would mirror and become trapped particles, leading to increased alpha loss. Such an effect was looked for during the shift experiment, however, no significant changes in alpha loss to the 90 degree lost alpha scintillator detector were observed during the shifts. It is calculated that the energy gained by an alpha-particle during the inward shift is sufficient to explain this result. However, an unexpected loss of partially thermalized alpha-particles

  4. Ionization and scintillation response of high-pressure xenon gas to alpha particles

    CERN Document Server

    Álvarez, V; Cárcel, S; Cebrián, S; Cervera, A; Conde, C A N; Dafni, T; Díaz, J; Egorov, M; Esteve, R; Evtoukhovitch, P; Fernandes, L M P; Ferrario, P; Ferreira, A L; Freitas, E D C; Gehman, V M; Gil, A; Goldschmidt, A; Gómez, H; Gómez-Cadenas, J J; González-Díaz, D; Gutiérrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Irastorza, I G; Jinete, M A; Labarga, L; Laing, A; Liubarsky, I; Lopes, J A M; Lorca, D; Losada, M; Luzón, G; Marí, A; Martín-Albo, J; Miller, T; Moiseenko, A; Monrabal, F; Monteiro, C M B; Mora, F J; Moutinho, L M; Vidal, J Muñoz; da Luz, H Natal; Navarro, G; Nebot, M; Nygren, D; Oliveira, C A B; Palma, R; Pérez, J; Aparicio, J L Pérez; Renner, J; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Segui, L; Serra, L; Shuman, D; Simón, A; Sofka, C; Sorel, M; Toledo, J F; Tomás, A; Torrent, J; Tsamalaidze, Z; Vázquez, D; Veloso, J F C A; Webb, R; White, J T; Yahlali, N

    2012-01-01

    High-pressure xenon gas is an attractive detection medium for a variety of applications in fundamental and applied physics. In this paper we study the transport properties of ionization electrons, and the mechanism of electron-ion recombination, in xenon gas at 10 bar pressure. For this purpose, we use a source of alpha particles in the NEXT-DEMO time projection chamber, the large scale prototype of the NEXT-100 neutrinoless double beta decay experiment, in three different drift electric field configurations. Our electron drift velocity and longitudinal diffusion results are similar to expectations based on available electron scattering cross sections on pure xenon, favoring low-diffusion models. In addition, two types of measurements addressing the connection between the ionization and scintillation yields were performed. On the one hand we observe, for the first time in xenon gas, large event-by-event correlated fluctuations between the ionization and scintillation signals, similarly to what has already bee...

  5. A Model for the Scattered Light Contribution and Polarization of the Diffuse $H\\alpha$ Galactic Background

    CERN Document Server

    Wood, K; Wood, Kenneth; Reynolds, Ron

    1999-01-01

    We present Monte Carlo simulations of the Diffuse H$\\alpha$ Galactic Background. Our models comprise direct and multiply scattered H$\\alpha$ radiation from the kpc scaleheight Warm Ionized Medium and midplane H II regions. The scattering is off dust that is assumed to be well mixed with the gas, with an axisymmetric density distribution taken from the literature. The results of our simulations are all-sky H$\\alpha$ images that enable us to separate out the contributions of direct and scattered radiation. We also determine how far the model H$\\alpha$ photons have traveled, i.e., how far we see into the Galaxy at H$\\alpha$. Our models reproduce the overall characteristics of the observed H$\\alpha$ background and predict the scattered H$\\alpha$ intensity at high latitudes is in the range 5% to 20% of the total intensity, in agreement with estimations based on [S II]/H$\\alpha$ and [O III]/H$\\alpha$ line ratio measurements. The polarization arising from dust scattering of H$\\alpha$ from midplane H II regions is pr...

  6. Synergy between chemotherapy and alpha particles: effects in cells directly hit and in bystander cells

    International Nuclear Information System (INIS)

    Full text: Radioimmunotherapy with alpha-emitting nuclides offers the potential for selective targeting of micrometastatic sites. The short range of alpha particles and limited penetration of the labeled antibody into the tumor make it difficult to deliver a lethal dose to all tumor cells. In an effort to improve the extent and uniformity of tumor cell kill, experiments are underway to evaluate the ability of chemotherapy agents to produce synergistic effects in cells directly hit by alpha particles and in bystander cells. An alpha particle cell irradiation system comprised of planar americium-241 alpha particle sources together with custom-made cell culture dishes with replaceable mylar bottoms has been constructed and characterized. By changing the alpha particle source, the dose rate to cells on the mylar membrane can be varied from 0.0013 Gy/min to 13 Gy/min. The residual range of the alpha particles after exiting the mylar membrane is approximately 30 ∝/m. Preliminary results with alpha particle exposure in the presence or absence of low concentrations of either taxol or oxaliplatin show evidence of synergistic effects. A series of plastic grids have been designed and constructed that can be interposed between the alpha particle source and the cells to partially block the alpha particles. The ratio of open area to shielded area is kept constant at 50% but the diameter and total number of circular openings in the grid is varied, thus changing the proportion of bystander cells present close to the edge between the open and shielded zones. This approach creates a two-dimensional model system for micrometastatic tumors of various sizes where the shielded areas represent the deeper portions of a tumor beyond the range of surface-bound alpha particles. Experiments are underway to determine whether there are synergistic effects between the chemotherapy agents and the bystander cells

  7. Alpha spectrometry for particle size determination of mineral sands dust samples

    International Nuclear Information System (INIS)

    A method is proposed for assessing the size distribution of the radioactive particles directly from the alpha spectrum of a dust sample. The residual range distribution of alpha particles emerging from a sphere containing a monoenergetic alpha emitter is simply a quadratic function of the diameter of the sphere. The residual range distribution from a typical dust particle closely approximates that of a sphere of the same mass. For mixtures of various size particles of similar density the (multiparticle) residual range distribution can thus readily be calculated for each of the alpha emitters contained in the particles. Measurement of the composite residual range distribution can be made in a vacuum alpha spectrometer provided the dust sample has no more than a monolayer of particles. The measured energy distribution is particularly sensitive to upper particle size distributions in the diameter region of 4μm to 20μm of 5 mg/cm3 density particles, i.e. 2 to 10 mg/ch2. For dust particles containing212Po or known ratios of alpha emitters a measured alpha spectrum can be unraveled to the underlying particle size distribution. Uncertainty in the size distribution has been listed as deserving research priority in the overall radiation protection program of the mineral sands industry. The proposed method had the potential of reducing this uncertainty, thus permitting more effective radiation protection control. 2 refs., 1 tabs., 1 figs

  8. Bond scission cross sections for alpha-particles in cellulose nitrate (LR115)

    CERN Document Server

    Barillon, R; Chambaudet, A; Katz, R; Stoquert, J P; Pape, A

    1999-01-01

    Chemical damage created by alpha-particles in cellulose nitrate (LR115) have been studied by infrared spectroscopy. This technique enables identifying the sensitive bonds and giving an order of magnitude of their scission cross sections for given alpha-particle energies. The high cross sections observed suggest a new description of the track etch velocity in this material.

  9. Computation and measurement of differential ranges of low-energy alpha particles in matter

    International Nuclear Information System (INIS)

    The stopping power formula of Bethe is discussed and is used to compute differential ranges of low-energy alpha particles in air, argon, aluminium and copper. A single radioactive source containing three active elements is used in experiments to measure the differential ranges in these materials. Finally a range-energy relationship for the alpha particles in air is deduced. (author)

  10. Simulation of Alpha Particles in Rotating Plasma Interacting with a Stationary Ripple

    Energy Technology Data Exchange (ETDEWEB)

    Abraham J. Fetterman and Nathaniel J. Fisch

    2011-01-11

    Superthermal ExB rotation can provide magnetohydrodynamic (MHD) stability and enhanced confinement to axisymmetric mirrors. However, the rotation speed has been limited by phenomena at end electrodes. A new prediction is that rotation might instead be produced using a magnetic ripple and alpha particle kinetic energy, in an extension of the alpha channeling concept. The interaction of alpha particles with the ripple results in visually interesting and practically useful orbits.

  11. Simulation of Alpha Particles in Rotating Plasma Interacting with a Stationary Ripple

    International Nuclear Information System (INIS)

    Superthermal ExB rotation can provide magnetohydrodynamic (MHD) stability and enhanced confinement to axisymmetric mirrors. However, the rotation speed has been limited by phenomena at end electrodes. A new prediction is that rotation might instead be produced using a magnetic ripple and alpha particle kinetic energy, in an extension of the alpha channeling concept. The interaction of alpha particles with the ripple results in visually interesting and practically useful orbits.

  12. Spectrometer for Particle Characterization With a New Multiple-Scattering Theory Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There are two major commercial types of light-scattering particle size analyzers: Static Light Scattering and Dynamic Light Scattering. They are expensive,...

  13. Heavy particle scattering by atomic and nuclear systems

    International Nuclear Information System (INIS)

    In this thesis quantum mechanical non-relativistic few-body problem is discussed. Basing on fundamentals ideas from Faddeev and Yakubovski three and four body equations are formulated and solved for fermionic atomic and nuclear systems. Former equations are modified to include long range interactions. Original results for nuclear and molecular physics were obtained: -) positively charged particle scattering on hydrogen atoms was considered; predictions for π+ → H, μ+ → H and p+ → H scattering lengths were given. Existence of an unknown, very weakly bound H+2 bound state was predicted. -) Motivated by the possible observation of bound four neutron structure at GANIL we have studied compatibility of such an existence within the current nuclear interaction models. -) 4 nucleon scattering at low energies was investigated. Results for n → 3H, p → 3H and p → 3He systems were compared with the experimental data. Validity of realistic nucleon-nucleon interaction models is questioned. (author)

  14. Measurement of dijet production in neutral current deep inelastic scattering at high Q**2 and determination of alpha_s

    CERN Document Server

    Breitweg, J; Abramowicz, H; Adamczyk, L; Adamus, M; Aghuzumtsyan, G; Ahn, S H; Amelung, C; Antonioli, P; Antonov, A; Arneodo, M; Badgett, W F; Bailey, D C; Bailey, D S; Bamberger, Andreas; Barakbaev, A N; Barbagli, G; Barbi, M S; Bari, G; Barreiro, F; Barret, O; Bashkirov, V; Basile, M; Bauerdick, L A T; Bednarek, B; Behrens, U; Bell, M; Bellagamba, L; Benen, A; Bertolin, A; Bienlein, J K; Bodmann, B; Bokel, C; Boogert, S; Boos, E G; Borras, K; Boscherini, D; Botje, M; Brock, I; Brook, N H; Brugnera, R; Bruni, A; Bruni, G; Brümmer, N; Bussey, Peter J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cartiglia, N; Chapin, D; Chekanov, S; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cirio, R; Cloth, P; Coboken, K; Coldewey, C; Cole, J E; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Costa, M; Crittenden, James Arthur; Cross, R; D'Agostini, Giulio; Dagan, S; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; De Wolf, E; Del Peso, J; Dementiev, R K; Deppe, O; Derrick, Malcolm; Desler, K; Devenish, R C E; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Eisenhardt, S; Engelen, J; Epperson, D E; Ermolov, P F; Eskreys, Andrzej; Fagerstroem, C P; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fox-Murphy, A; Fricke, U; Fusayasu, T; Gabareen, A; Gadaj, T; Galea, R; Gallo, E; García, G; Garfagnini, A; Geiser, A; Gendner, N; Gialas, I; Gilmore, J; Ginsburg, C M; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Golubkov, Yu A; Goncalo, R; González, O; Graciani, R; Grijpink, S; Grosse-Knetter, J; Grzelak, G; Gwenlan, C; Göttlicher, P; Haas, T; Hain, W; Hamatsu, R; Hart, J C; Hartmann, H; Hartner, G F; Hayes, M E; Heaphy, E A; Heath, G P; Heath, H F; Hebbel, K; Heinloth, K; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Iacobucci, G; Iannotti, L; Inuzuka, M; Irrgang, P; Ishii, T; Jakob, H P; Jelen, K; Jeoung, H Y; Jones, T W; Kananov, S; Kappes, A; Karshon, U; Katkov, I I; Katz, U F; Kcira, D; Kerger, R; Khein, L A; Kim, C L; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Klimek, K H; Koch, W; Koffeman, E; Kohno, T; Kooijman, P M; Koop, T; Korotkova, N A; Korzhavina, I A; Kotanski, Andrzej; Kowal, A M; Kowalski, H; Kowalski, T; Krakauer, D A; Kreisel, A; Kuze, M; Kuzmin, V A; Kötz, U; Labarga, L; Labes, H; Lane, J B; Lee, J H; Lee, S B; Lee, S W; Levi, G; Levman, G M; Levy, A; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, W; Liu, X; Lohrmann, E; Long, K R; Longhin, A; López-Duran-Viani, A; Lukina, O Yu; Lupi, A; Löhr, B; Ma, K J; MacDonald, N; Magill, S; Mankel, R; Margotti, A; Marini, G; Markun, P; Martens, J; Martin, J F; Martínez, M; Maselli, S; Massam, Thomas; Mastroberardino, A; Matsushita, T; Matsuzawa, K; Mattingly, M C K; Mattingly, S E K; McCance, G J; McCubbin, N A; Mellado, B; Meyer, A; Milite, M; Miller, D B; Mirea, A; Monaco, V; Moritz, M; Musgrave, B; Nagano, K; Nania, R; Nigro, A; Nishimura, T; Notz, D; Nowak, R J; Oh, B Y; Okrasinski, J R; Olkiewicz, K; Pac, M Y; Padhi, S; Paganis, S; Palmonari, F; Parenti, A; Park, I H; Park, S K; Paul, E; Pavel, N; Pawlak, J M; Pawlak, R; Pelfer, P G; Pellegrino, A; Peroni, C; Pesci, A; Petrucci, M C; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Raach, H; Rautenberg, J; Redondo, I; Reeder, D D; Repond, J; Robins, S A; Rodrigues, E; Rohde, M; Rulikowska-Zarebska, E; Ruske, O; Ruspa, M; Sabetfakhri, A; Sacchi, R; Sadrozinski, H F W; Salehi, H; Sampson, S; Sartorelli, G; Saull, P R B; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Schnurbusch, H; Sciulli, F; Scott, J; Seiden, A; Selonke, F; Shah, T P; Shcheglova, L M; Sinclair, L E; Skillicorn, Ian O; Smalska, B; Smith, W H; Solano, A; Solomin, A N; Son, D; Sosnovtsev, V V; Staiano, A; Stairs, D G; Stanco, L; Stanek, R; Stifutkin, A; Stonjek, S; Stopa, P; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutton, M R; Szuba, D; Tandler, J; Tapper, A D; Tapper, R J; Tassi, E; Terron, J; Tiecke, H G; Tokushuku, K; Toothacker, W S; Tsurugai, T; Tuning, N; Turcato, M; Tymieniecka, T; Umemori, K; Vaiciulis, A W; Van Sighem, A; Vázquez, M E; Velthuis, J J; Vlasov, N N; Voss, K C; Vossebeld, Joost Herman; Walczak, R; Walker, R; Waugh, R; Weber, A; West, B J; Whitmore, J J; Wichmann, R; Wick, K; Wieber, H; Wiggers, L; Wildschek, T; Williams, D C; Wing, M; Wodarczyk, M; Wolf, G; Wollmer, U; Wróblewski, A K; Wölfle, S; Yamada, S; Yamashita, T; Yamazaki, Y; Yildirim, A; Yoshida, R; Youngman, C; Zakrzewski, J A; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A

    2001-01-01

    Dijet production has been studied in neutral current deep inelastic e+p scattering for 470 < Q**2 < 20000 GeV**2 with the ZEUS detector at HERA using an integrated luminosity of 38.4 pb**{-1}. Dijet differential cross sections are presented in a kinematic region where both theoretical and experimental uncertainties are small. Next-to-leading-order (NLO) QCD calculations describe the measured differential cross sections well. A QCD analysis of the measured dijet fraction as a function of Q**2 allows both a precise determination of alpha_s(M_Z) and a test of the energy-scale dependence of the strong coupling constant. A detailed analysis provides a realistic estimate of the uncertainties of the NLO QCD cross sections arising from the parton distribution functions of the proton. The value of alpha_s(M_Z), as determined from the QCD fit, is alpha_s(M_Z) = 0.1166 +- 0.0019 (stat.) {+ 0.0024}_{- 0.0033} (exp.)} {+ 0.0057}_{- 0.0044} (th.).

  15. Radiative Møller scattering involving polarized particles

    Energy Technology Data Exchange (ETDEWEB)

    Zykunov, V. A., E-mail: zykunov@cern.ch [Belarusian State University of Transport (Belarus)

    2015-06-15

    A method for taking into account radiative events in experiments aimed at studying Møller scattering with polarized particles was developed for an arbitrary implementation of such experiments. A computer code used to perform a numerical analysis with allowance for the kinematical conditions of the MOLLER experiment at the Thomas Jefferson National Accelerator Facility (Jefferson Lab or JLab) was constructed. The respective results were compared with their counterparts obtained in the soft-photon approximation.

  16. Determination of the range of alpha particles in SSNTD by optical density method

    CERN Document Server

    El-Hofy, M; Arafa, W

    1999-01-01

    A technique based on the optical density (D) measurement of the etched track is useful for charged particles spectroscopy using SSNTD. It was shown that the stopping power of alpha particles in CR-39 is proportional to D. We measured the optical density and derived an expression to estimate the range of alpha particles in CR-39 detector as a function of the bulk etching rate and etching time. The relation between the etching time, track parameters (depth, radius) and D for different alpha particles energy and etching conditions were studied. A relation describing D as a function of track size is proposed.

  17. Oxygen depth profiling in Kr{sup +}-implanted polycrystalline alpha titanium by means of {sup 16}O({alpha},{alpha}){sup 16}O resonance scattering

    Energy Technology Data Exchange (ETDEWEB)

    Nsengiyumva, S., E-mail: schadnse@hotmail.com [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa); Department of Physics and Electronics, Rhodes University, Grahamstown 6140 (South Africa); Department of Physics, Kigali Institute of Education, P.O. Box 5039 Kigali (Rwanda); Riviere, J.P. [Laboratoire de Physique des Materiaux UMR6630-CNRS, 86960 (France); Raji, A.T.; Comrie, C.M.; Britton, D.T.; Haerting, M. [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa)

    2011-07-15

    The {sup 16}O({alpha},{alpha}){sup 16}O resonance scattering was applied to study the effects of ion implantation on the oxygen distribution in the near surface region of polycrystalline titanium implanted with 180 keV krypton ions at fluences, ranging between 1 x 10{sup 14} and 5 x 10{sup 15} Kr{sup +}/cm{sup 2}. Two sample sets were chosen: as-received polycrystalline titanium discs rolled and annealed in half-hard condition which had a thick oxygen layer and similar samples in which this surface layer was removed by polishing. An increase of the mean oxygen concentration observed in both unpolished and polished samples at low fluence suggests a knock-on implantation of surface oxygen atoms. At high fluence, an overall decrease in the mean oxygen concentration and mean oxygen depth suggests an out-diffusion of near-surface oxygen atoms.

  18. The biokinetics of alpha-particle emitting radiopharmaceuticals

    International Nuclear Information System (INIS)

    The past two decades have seen wide interest in the application of alpha-particle emitting radionuclides for targeted endoradiotherapy and a large number of compounds labeled with 211At (T1/2 7.21 h), 212Bi (T1/2 1 h) or 213Bi (T1/2 0.78 h) have been studied. Knowledge of the biokinetic behaviour of such agents is important both for their optimal clinical exploitation and for general radiological protection purposes. Animal studies of the distribution and retention of 211At compounds, including ionic astatide, substituted aromatic compounds and labelled monoclonal antibodies, have provided new information on the biochemistry of astatine. With respect the thyroid gland the uptake of the astatide ion has been shown to be very much lower than that of the iodide ion. Less information is available for 212Bi-labelled radiopharmaceuticals. The available data for both 211At and 212Bi radiopharmaceuticals are reviewed. Cautious generic biokinetic models for inorganic and simple organic compounds of 211At and 212Bi; for [211At]-, and [212Bi]-biphosphonates and for [211At]-, and [212Bi]-monoclonal antibodies, are proposed for use in general radiological protection when compound-specific data are not available. (orig.)

  19. The biokinetics of alpha-particle emitting radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, D.M. [School of Chemistry, Cardiff Univ., Cardiff (United Kingdom); Duffield, J.R. [Faculty of Applied Sciences, Univ. of the West of England, Bristol (United Kingdom)

    2005-07-01

    The past two decades have seen wide interest in the application of alpha-particle emitting radionuclides for targeted endoradiotherapy and a large number of compounds labeled with {sup 211}At (T{sup 1}/{sub 2} 7.21 h), {sup 212}Bi (T{sup 1}/{sub 2} 1 h) or {sup 213}Bi (T{sup 1}/{sub 2} 0.78 h) have been studied. Knowledge of the biokinetic behaviour of such agents is important both for their optimal clinical exploitation and for general radiological protection purposes. Animal studies of the distribution and retention of {sup 211}At compounds, including ionic astatide, substituted aromatic compounds and labelled monoclonal antibodies, have provided new information on the biochemistry of astatine. With respect the thyroid gland the uptake of the astatide ion has been shown to be very much lower than that of the iodide ion. Less information is available for {sup 212}Bi-labelled radiopharmaceuticals. The available data for both {sup 211}At and {sup 212}Bi radiopharmaceuticals are reviewed. Cautious generic biokinetic models for inorganic and simple organic compounds of {sup 211}At and {sup 212}Bi; for [{sup 211}At]-, and [{sup 212}Bi]-biphosphonates and for [{sup 211}At]-, and [{sup 212}Bi]-monoclonal antibodies, are proposed for use in general radiological protection when compound-specific data are not available. (orig.)

  20. The Use Of Optical Properties Of Cr-39 In Alpha Particle Equivalent Dose Measurements

    International Nuclear Information System (INIS)

    In this work, optical properties of alpha irradiated Cr-39 were measured as a function of optical photon wavelength from 200-1100 nm. Optical energy gap and optical absorption at finite wavelength was also calculated and correlated to alpha fluence and dose equivalent. Alpha doses were calculated from the corresponding irradiation fluence and specific energy loss using TRIM computer program. It was found that, the optical absorption of unattached Cr-39 was varied with alpha fluence and corresponding equivalent doses. Also the optical energy gab was varied with fluence and dose equivalent of alpha particles. This work introduces a reasonably simple method for the Rn dose equivalent calculation by Cr-39 track

  1. Gaseous swelling model in the alpha-particles straggling field

    International Nuclear Information System (INIS)

    In the work for the physical model the following key presuppositions were accepted: alpha particles Gauss distribution in the straggling field is expected; the helium embryo is the helium atom plus the two vacancies; gaseous pores coalescence is resulted their migration in the tension field and Brownian movement; the preservation of helium atoms in the coalescence process is expected; it consequence is swelling. At the initial stage the behavior of pores ensemble with taking into account of a point defects formation during irradiation process have been analyzed. It is expected, that development of this ensemble will be take place during the following annealing of the matrix. The main presuppositions on the this stage of calculation are as follows: there are the principal elements of the microstructure - are taking into account in the kinetic equations - implanted helium interstitials, vacancies, dislocation network, Frank loops, pores; it is excepted, that two interstitial helium atoms form the pore embryo; two interstitials Frank loops at distances between components equal to lattice constant; mechanisms of pores formation in the matrix and dislocation are expected different; the additional channel of pores growth is Frank loops dropping. The typical kinetic equation for interstitial from complete equation system is presented. The pores ensemble evolution for iron irradiated by helium ions with energy E=400 keV up to integral dose 101|7 ion/cm2 at 100 deg C temperature and following annealing at temperature 800 deg C is calculated. It is shown that pores distribution by sizes is shifting forward big sizes with increase of annealing time

  2. The simulation of the response of superheated emulsion to alpha particles

    International Nuclear Information System (INIS)

    The response of superheated emulsion of liquid perfluorobutane (C4F10; b.p.:  −1.7o C) to alpha particle has been studied by performing the simulation using GEANT3.21 toolkit. The simulations have been performed to generate two different experimental situations. In one case, the alpha contamination is present only in polymer and in another case, the alpha contamination is present both in polymer and active liquid. The value of the nucleation parameter, k, for bubble nucleation induced by alpha particle in superheated emulsion detector is determined by comparing the simulated normalized count rates with the available experimental results. The results show that the nucleation parameter for alpha particle in C4F10 liquid is about 0.19. The energy and position of alpha particle are not able to change the response of the alpha particle in C4F10 liquid. The recoiling nuclei associated with the alpha decay chain are responsible for making the detector sensitive at lower threshold temperatures

  3. The simulation of the response of superheated emulsion to alpha particles

    Science.gov (United States)

    Seth, Susnata; Das, Mala

    2016-04-01

    The response of superheated emulsion of liquid perfluorobutane (C4F10; b.p.: ‑1.7o C) to alpha particle has been studied by performing the simulation using GEANT3.21 toolkit. The simulations have been performed to generate two different experimental situations. In one case, the alpha contamination is present only in polymer and in another case, the alpha contamination is present both in polymer and active liquid. The value of the nucleation parameter, k, for bubble nucleation induced by alpha particle in superheated emulsion detector is determined by comparing the simulated normalized count rates with the available experimental results. The results show that the nucleation parameter for alpha particle in C4F10 liquid is about 0.19. The energy and position of alpha particle are not able to change the response of the alpha particle in C4F10 liquid. The recoiling nuclei associated with the alpha decay chain are responsible for making the detector sensitive at lower threshold temperatures.

  4. Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles

    International Nuclear Information System (INIS)

    The objective of our research work is to provide -- with the aid of biophysical models of radiation action -- information on human risks following exposure to radon alpha particles. The approach proposed consists of (1) developing appropriate models (parametric and non-parametric) for alpha radiation induction of relevant end points (survival, cellular transformation), (2) providing an accurate physical characterization of the particle tracks in terms of nanodosimetric distributions, (3) supporting the models by detailed, molecular studies of the direct and indirect effects of alpha particles on DNA. Activities in the second year of this project are described

  5. Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The objective of our research work is to provide -- with the aid of biophysical models of radiation action -- information on human risks following exposure to radon alpha particles. The approach proposed consists of (1) developing appropriate models (parametric and non-parametric) for alpha radiation induction of relevant end points (survival, cellular transformation), (2) providing an accurate physical characterization of the particle tracks in terms of nanodosimetric distributions, (3) supporting the models by detailed, molecular studies of the direct and indirect effects of alpha particles on DNA. Activities in the second year of this project are described.

  6. Transport theory for energetic alpha particles in finite aspect ratio tokamaks with broken symmetry

    Science.gov (United States)

    Shaing, K. C.; Schlutt, M.; Lai, A. L.

    2016-02-01

    Transport theory for the energetic alpha particles in finite aspect ratio tokamaks with broken symmetry is developed for the case where the slowing down collision operator dominates. The transport fluxes in the 1 /ν and superbanana plateau regimes are derived. Here, ν is the typical collision frequency. They can be used in modeling the energy loss of the alpha particles in thermonuclear fusion reactors. Numerical realizations of the superbanana orbits of alpha particles in tokamaks with broken symmetry are also presented. The existence of the superbananas corroborates the predictions of the theories presented here and elsewhere.

  7. Asymptotic neutron scattering laws for anomalously diffusing quantum particles.

    Science.gov (United States)

    Kneller, Gerald R

    2016-07-28

    The paper deals with a model-free approach to the analysis of quasielastic neutron scattering intensities from anomalously diffusing quantum particles. All quantities are inferred from the asymptotic form of their time-dependent mean square displacements which grow ∝t(α), with 0 ≤ α diffusion (α = 0) is here explicitly included. We discuss in particular the intermediate scattering function for long times and the Fourier spectrum of the velocity autocorrelation function for small frequencies. Quantum effects enter in both cases through the general symmetry properties of quantum time correlation functions. It is shown that the fractional diffusion constant can be expressed by a Green-Kubo type relation involving the real part of the velocity autocorrelation function. The theory is exact in the diffusive regime and at moderate momentum transfers. PMID:27475344

  8. Surface-integral formulation of scattering theory for charged particles

    International Nuclear Information System (INIS)

    Full text: Collisions in the realm of atomic and nuclear physics not only have many practical applications, but also form the testing ground for the underlying quantum collision theory. The last decade has seen extraordinary theoretical progress in the field of electron-impact atomic breakup problem [1]. This problem was challenging to solve due to formal and computational difficulties associated with the long-range Coulomb potential. Presently, however, the electron-induced breakup processes can be calculated accurately for simple targets such as atomic hydrogen and helium, in the kinematically complete form. We report on how the computational progress has resulted in a deeper understanding of the formal theory of Coulomb few-body scattering [2] and how corresponding calculations of nuclear breakup reactions can benefit from this development. In quantum collision theory it is customary to define the scattering amplitude in terms of the scattering wave function and the potential of interaction. Despite the fact that the Coulomb wave function and the Coulomb potential are both known analytically, the conventional theory is not able to provide such a standard definition for the amplitude of scattering of two charged particles, which yields the Rutherford cross section. As far as breakup of a bound state of two particles in a system of three charged particles is concerned, here again the theory fails to give a formal definition for calculating the breakup amplitude in the post form in terms of the total scattering wave function describing the process. The reason for this failure is that charged particles continue to interact with each other even at infinite separation due to the long-range nature of the Coulomb potential, something the conventional theory cannot handle. We present a new formulation of scattering theory applicable to arbitrary two and three-body systems with both short-range and Coulomb long-range potentials [2]. The formalism is based on a surface

  9. Asymptotic neutron scattering laws for anomalously diffusing quantum particles

    Science.gov (United States)

    Kneller, Gerald R.

    2016-07-01

    The paper deals with a model-free approach to the analysis of quasielastic neutron scattering intensities from anomalously diffusing quantum particles. All quantities are inferred from the asymptotic form of their time-dependent mean square displacements which grow ∝tα, with 0 ≤ α scattering function for long times and the Fourier spectrum of the velocity autocorrelation function for small frequencies. Quantum effects enter in both cases through the general symmetry properties of quantum time correlation functions. It is shown that the fractional diffusion constant can be expressed by a Green-Kubo type relation involving the real part of the velocity autocorrelation function. The theory is exact in the diffusive regime and at moderate momentum transfers.

  10. Experiments with nuclear track detectors for diagnostics of protons and alpha particles from fusion plasmas

    International Nuclear Information System (INIS)

    This report deals with the experimental development of a method of detecting charged particles from nuclear fusion plasmas by means of nuclear track detectors. The latter were bombarded with protons and alpha particles poduced with an accelerator from the fusion reactions D (3He, p) α and D (D, p) T. In the parameter range expected for the particles emitted from thermonuclearly burning plasma the detection probabilities of protons and alpha particles were determined as functions of the energy and angle of incidence, and also the crater radii and depths as functions of the particle species, particle energy and etching time. The following results were obtained: For alpha particles the detection probability in the entire energy range investigated and at angles of incidence between 00 and 700 to the foil normal is about 100%. The alpha particle energy can be approximately determined from the track depths. For protons, on the other hand, the detection probability already decreases monotonically at low energies as the energy increases, becoming zero at about Esub(p) = 7 MeV. Proton detection is only possible at angles of incidence between 00 and 300. The proton energy can be approximately determined from the track radii. The measured energy dependence of the track radii and depths of alpha particles and protons and their angular dependence can be explained with a simple model calculation in which it is assumed that the track etching rate decreases as the particle range in the material of the nuclear track foils increases. (orig.)

  11. A submillimeter galaxy illuminating its circumgalactic medium: Ly-alpha scattering in a cold, clumpy outflow

    CERN Document Server

    Geach, J E; Alexander, D M; Blain, A W; Bremer, M; Chapin, E L; Chapman, S C; Clements, D L; Coppin, K E K; Dunlop, J S; Farrah, D; Jenness, T; Koprowski, M P; Michalowski, M J; Robson, E I; Scott, D; Smith, D J B; Spaans, M; Swinbank, A M; van der Werf, P

    2014-01-01

    We report the detection at 850um of the central source in SSA22-LAB1, the archetypal Lyman-alpha Blob (LAB), a 100kpc-scale radio-quiet emission-line nebula at z=3.1. The flux density of the source, $S_{850}=4.6\\pm1.1$mJy implies the presence of a galaxy, or group of galaxies, with a total luminosity of $L_{\\rm IR}\\approx10^{12}L_\\odot$. The position of an active source at the center of a ~50kpc-radius ring of linearly polarized Ly-alpha emission detected by Hayes et al. (2011) suggests that the central source is leaking Ly-alpha photons preferentially in the plane of the sky, which undergo scattering in HI clouds at large galactocentric radius. The Ly-alpha morphology around the submillimeter detection is reminiscent of biconical outflow, and the average Ly-alpha line profiles of the two `lobes' are dominated by a red peak, expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evi...

  12. Charged Particle Multiplicities in Deep Inelastic Scattering at HERA

    CERN Document Server

    Aïd, S; Andreev, V; Andrieu, B; Appuhn, R D; Babaev, A; Ban, Y; Baranov, P S; Barrelet, E; Barschke, R; Bartel, Wulfrin; Barth, Monique; Bassler, U; Beck, H P; Behrend, H J; Belousov, A; Berger, C; Bernardi, G; Bertrand-Coremans, G H; Besançon, M; Beyer, R; Biddulph, P; Bispham, P; Bizot, J C; Blobel, Volker; Borras, K; Botterweck, F; Boudry, V; Braemer, A; Braunschweig, W; Brisson, V; Bruel, P; Bruncko, Dusan; Brune, C R; Buchholz, R; Buniatian, A Yu; Burke, S; Burton, M; Bähr, J; Büngener, L; Bürger, J; Büsser, F W; Calvet, D; Campbell, A J; Carli, T; Charlet, M; Chechelnitskii, S; Chernyshov, V; Clarke, D; Clegg, A B; Clerbaux, B; Cocks, S P; Contreras, J G; Cormack, C; Coughlan, J A; Courau, A; Cousinou, M C; Cozzika, G; Criegee, L; Cussans, D G; Cvach, J; Dagoret, S; Dainton, J B; Dau, W D; Daum, K; David, M; Davis, C L; De Wolf, E A; Delcourt, B; Di Nezza, P; Dirkmann, M; Dixon, P; Dlugosz, W; Dollfus, C; Dowell, John D; Dreis, H B; Droutskoi, A; Duhm, H; Dünger, O; Ebert, J; Ebert, T R; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, Franz; Eisenhandler, Eric F; Ellison, R J; Elsen, E E; Erdmann, M; Erdmann, W; Evrard, E; Fahr, A B; Favart, L; Fedotov, A; Feeken, D; Felst, R; Feltesse, Joel; Ferencei, J; Ferrarotto, F; Flamm, K; Fleischer, M; Flieser, M; Flügge, G; Fomenko, A; Fominykh, B A; Formánek, J; Foster, J M; Franke, G; Fretwurst, E; Gabathuler, Erwin; Gabathuler, K; Gaede, F; Garvey, J; Gayler, J; Gebauer, M; Genzel, H; Gerhards, R; Glazov, A; Goerlach, U; Gogitidze, N; Goldberg, M; Goldner, D; Golec-Biernat, Krzysztof J; González-Pineiro, B; Gorelov, I V; Grab, C; Greenshaw, T J; Griffiths, R K; Grindhammer, G; Gruber, A; Gruber, C; Grässler, Herbert; Grässler, R; Görlich, L; Haack, J; Hadig, T; Haidt, Dieter; Hajduk, L; Hampel, M; Haynes, W J; Heinzelmann, G; Henderson, R C W; Henschel, H; Herynek, I; Hess, M F; Hewitt, K; Hildesheim, W; Hiller, K H; Hilton, C D; Hladky, J; Hoeger, K C; Hoffmann, D; Holtom, T; Hoppner, M; Horisberger, R P; Hudgson, V L; Hufnagel, H; Hütte, M; Ibbotson, M; Itterbeck, H; Jacholkowska, A; Jacobsson, C; Jaffré, M; Janoth, J; Jansen, T; Johnson, D P; Jung, H; Jönsson, L B; Kalmus, Peter I P; Kander, M; Kant, D; Kaschowitz, R; Kathage, U; Katzy, J M; Kaufmann, H H; Kaufmann, O; Kazarian, S; Kenyon, Ian Richard; Kermiche, S; Keuker, C; Kiesling, C; Klein, M; Kleinwort, C; Knies, G; Kolanski, H; Kole, F; Kolya, S D; Korbel, V; Korn, M; Kostka, P; Kotelnikov, S K; Krasny, M W; Krehbiel, H; Krämerkämper, T; Krücker, D; Kuhlen, M; Kurca, T; Kurzhofer, J; Köhler, T; Köhne, J H; Küster, H; Lacour, D; Laforge, B; Lander, R; Landon, M P J; Lange, W; Langenegger, U; Laporte, J F; Lebedev, A; Lehner, F; Levonian, S; Lindström, G; Lindstrøm, M; Link, J; Linsel, F; Lipinski, J; List, B; Lobo, G; Loch, P; Lomas, J W; Lubimov, V; Lüke, D; López, G C; Magnussen, N; Malinovskii, E I; Mani, S; Maracek, R; Marage, P; Marks, J; Marshall, R; Martens, J; Martin, G; Martin, R D; Martyn, H U; Martyniak, J; Mavroidis, A; Maxfield, S J; McMahon, S J; Mehta, A; Meier, K; Meyer, A; Meyer, H; Meyer, J; Meyer, P O; Migliori, A; Mikocki, S; Milstead, D; Moeck, J; Moreau, F; Morris, J V; Mroczko, E; Murín, P; Müller, G; Müller, K; Nagovitsin, V; Nahnhauer, R; Naroska, Beate; Naumann, T; Negri, I; Newman, P R; Newton, D; Neyret, D; Nguyen, H K; Nicholls, T C; Niebergall, F; Niebuhr, C B; Niedzballa, C; Niggli, H; Nisius, R; Nowak, G; Noyes, G W; Nyberg-Werther, M; Oakden, M N; Oberlack, H; Olsson, J E; Ozerov, D; Palmen, P; Panaro, E; Panitch, A; Pascaud, C; Patel, G D; Pawletta, H; Peppel, E; Phillips, J P; Pieuchot, A; Pitzl, D; Pope, G; Prell, S; Pérez, E; Rabbertz, K; Reimer, P; Reinshagen, S; Rick, Hartmut; Riech, V; Riedlberger, J; Riepenhausen, F; Riess, S; Rizvi, E; Robertson, S M; Robmann, P; Roloff, H E; Roosen, R; Rosenbauer, K; Rostovtsev, A A; Rouse, F; Royon, C; Rusakov, S V; Rybicki, K; Rädel, G; Rüter, K; Sankey, D P C; Schacht, P; Schiek, S; Schleif, S; Schleper, P; Schmidt, D; Schmidt, G; Schröder, V; Schuhmann, E; Schwab, B; Schöning, A; Sefkow, F; Seidel, M; Sell, R; Semenov, A A; Shekelian, V I; Shevyakov, I; Shtarkov, L N; Siegmon, G; Siewert, U; Sirois, Y; Skillicorn, Ian O; Smirnov, P; Smith, J R; Solochenko, V; Soloviev, Yu V; Specka, A E; Spiekermann, J; Spielman, S; Spitzer, H; Squinabol, F; Starosta, R; Steenbock, M; Steffen, P; Steinberg, R; Steiner, H; Steinhart, J; Stella, B; Stellberger, A; Stier, J; Stiewe, J; Stolze, K; Straumann, U; Struczinski, W; Stösslein, U; Sutton, J P; Tapprogge, Stefan; Tasevsky, M; Theissen, J; Thiebaux, C; Thompson, G; Truöl, P; Tsipolitis, G; Turnau, J; Tutas, J; Uelkes, P; Usik, A; Valkár, S; Valkárová, A; Vallée, C; Van Esch, P; Van Mechelen, P; Van den Plas, D; Vazdik, Ya A; Verrecchia, P; Villet, G; Wacker, K; Wagener, A; Wagener, M; Walther, A; Waugh, B; Weber, G; Weber, M; Wegener, D; Wegner, A; Wengler, T; Werner, M; West, L R; Wiesand, S; Wilksen, T; Willard, S; Winde, M; Winter, G G; Wittek, C; Wobisch, M; Wünsch, E; Zarbock, D; Zhang, Z; Zhokin, A S; Zini, P; Zomer, F; Zsembery, J; Zuber, K; Zur Nedden, M; Zácek, J; de Roeck, A; von Schlippe, W

    1996-01-01

    Using the H1 detector at HERA, charged particle multiplicity distributions in deep inelastic ep scattering have been measured over a large kinematical region. The evolution with $W$ and $Q^2$ of the multiplicity distribution and of the multiplicity moments in pseudorapidity domains of varying size is studied in the current fragmentation region of the hadronic centre-of-mass frame. The results are compared with data from fixed target lepton-nucleon interactions, $e^+e^-$ annihilations and hadron-hadron collisions as well as with expectations from QCD based parton models. Fits to the Negative Binomial and Lognormal distributions are presented.

  13. Cluster-shell competition in systems with a few alpha particles and valence neutrons

    International Nuclear Information System (INIS)

    We construct nuclear wave functions from alpha clusters and some additional valence nucleons, and allow the inter-cluster distance to change and one alpha to dissolve from the (0s)4 structure as a result of the nuclear interaction. The change of the inter-cluster distance and the dissolution of the alpha particle can be interpreted as resulting from the competition of the 'shell model' and 'cluster model'. We demonstrate this competition through a few parameters.

  14. CIT alpha particle extraction and measurement: Low-Z ablation cloud profile simulation for alpha-particle diagnostics

    International Nuclear Information System (INIS)

    In order to determine the expected properties of the ablation cloud of low-Z pellets interacting with a thermonuclear plasma, which in turn is proposed as a charge-neutralization medium for confined alpha particles, a numerical program has been developed. The physical model for this program is based on Park's low-Z pellet-plasma interaction model for the interior of the cloud adjacent to the pellet's surface out to the sonic surface (roughly, a millimeter in separation), and then propagating outward from this region using the conservation laws of enthalpy, momentum, and mass, along with the assumption of charge-state equilibrium. The effects of local heating by the plasma electrons slowing down in the cloud, and ionization of the ablatant material are treated self-consistently in the model. In collaboration with Dr. Paul Parks of General Atomics Corporation, a joint ODU-GAC research plan for modeling low-Z pellet-plasma interactions has been devised, and considerable progress has been made in its implementation. Recently, using a constraint in the ablatant flow, so that it approximates its observed flow along the magnetic field, results from the program were obtained which could be compared with the results from the GAC experiments on TEXT. The predictions of the program are in poor agreement with the TEXT data as to the dimensions of the C+3 region of the cloud along the magnetic field. The failure of the model appears to be the breakdown of the assumption that charge-state equilibrium exists in the cloud. This problem is particularly severe for the TEXT parameters so modifications in the model to include non-equilibrium effects are being implemented

  15. CIT alpha particle extraction and measurement: Low-Z ablation cloud profile simulation for alpha-particle diagnostics

    International Nuclear Information System (INIS)

    In order to determine the expected properties of the ablation cloud of low-Z pellets interacting with a thermonuclear plasma, which in turn is proposed as a charge-neutralization medium for confined alpha particles, a numerical program has been developed. The physical model for this program is based on Parks' low-Z pellet-plasma interaction model for the interior of the cloud adjacent to the pellet's surface out to the sonic surface (roughly, a millimeter in separation) and then propagating outward from this region using the conservation laws of enthalpy, momentum, and mass, along with the assumption of charge-state equilibrium. The effects of local heating by the plasma electrons slowing down in the cloud, and ionization of the ablatant material are treated self-consistently in the model. In collaboration with Dr. Paul Parks of General Atomics Corporation, a joint ODU-GAC research plan for modeling low-Z pellet-plasma interactions has been devised, and considerable progress has been made in its implementation. Recently, using a constraint in the ablatant flow, results from the program were obtained which could be compared with the results from the GAC experiments on TEXT. The predictions of the program are in pretty good agreement with the TEXT data as to the dimensions of the C+3 region of the cloud along the magnetic field. Also a small improvement has been made in the low-Z pellet plasma-penetration program, which brings the predictions of the model in closer agreement with the carbon pellet injection experiments on TFTR. 22 refs., 3 figs

  16. Anomalous loss of DT alpha particles in the Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    An escaping alpha collector probe has been developed for TFTR's DT phase. Energy distributions of escaping alphas have been determined by measuring the range of α-particles implanted into nickel foils located within the alpha collector. Results at 1.0 MA of plasma current are in good agreement with predictions for first orbit alpha loss. Results at 1.8 MA, however, show a significant anomalous loss of partially thermalized alphas (in addition to the expected first orbit loss), which is not observed with the lost alpha scintillator detectors in DT plasmas, but does resemble the anomalous delayed loss seen in DD plasmas. None of the candidate explanations proposed thus far are fully consistent with the anomalous loss observations. An experiment designed to study the effect of plasma major radius shifts on α-particle loss has led to a better understanding of α-particle dynamics in tokamaks. Intuitively, one might suppose that confined marginally passing α-particles forced to move toward higher magnetic field during an inward major radius shift (i.e., compression) would mirror and become trapped particles, leading to increased alpha loss. Such an effect was looked for during the shift experiment, however, no significant changes in alpha loss to the 90 degree lost alpha scintillator detector were observed during the shifts. It is calculated that the energy gained by an α-particle during the inward shift is sufficient to explain this result. However, an unexpected loss of partially thermalized α-particles near the passing/trapped boundary was observed to occur between inward and outward shifts at an intermediate value of plasma current (1.4 MA). This anomalous loss feature is not yet understood

  17. Study of /sup 3/H+. cap alpha. and /sup 3/He+. cap alpha. elastic scattering in a state with zero orbital angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Chopovskii, L. L.

    1988-12-01

    An asymptotic wave function of the relative motion of clusters at zero interaction energy is derived in the oscillator representation. The set of equations of the algebraic version of the resonating-group method (RGM) is transformed to the zero-energy limit of the relative cluster motion. The /sup 3/H+..cap alpha.. and /sup 3/He+..cap alpha.. scattering lengths are calculated in the single-channel RGM variant on the basis of the derived equations. The possibility of experimentally observing large scattering lengths for light charged clusters is predicted, viz., /similar to/10--23 F in the /sup 3/H+..cap alpha.. channel and /similar to/30--82 F in the /sup 3/He+..cap alpha.. channel.

  18. High precision $^{113}$In($\\alpha,\\alpha$)$^{113}$In elastic scattering at energies around the Coulomb barrier for the astrophysical $\\gamma$ process

    CERN Document Server

    Kiss, G G; Fülöp, Zs; Rauscher, T; Gyürky, Gy; Szücs, T; Halász, Z; Somorjai, E; Ornelas, A; Yalcin, C; Güray, R T; Özkan, N

    2013-01-01

    The $\\gamma$ process in supernova explosions is thought to explain the origin of proton-rich isotopes between Se and Hg, the so-called $p$ nuclei. The majority of the reaction rates for $\\gamma$ process reaction network studies has to be predicted in Hauser-Feshbach statistical model calculations using global optical potential parameterizations. While the nucleon+nucleus optical potential is fairly known, for the $\\alpha$+nucleus optical potential several different parameterizations exist and large deviations are found between the predictions calculated using different parameter sets. By the measurement of elastic $\\alpha$-scattering angular distributions at energies around the Coulomb barrier a comprehensive test for the different global $\\alpha$+nucleus optical potential parameter sets is provided. Between 20$^{\\circ}$ and 175$^{\\circ}$ complete elastic alpha scattering angular distributions were measured on the $^{113}$In \\textit{p} nucleus with high precision at E$_{c.m.}$ = 15.59 and 18.82 MeV. The elast...

  19. Cross sections of nuclear reactions induced by protons, deuterons, and alpha particles. Pt.6. Phosphorus

    International Nuclear Information System (INIS)

    Cross sections are reviewed for nuclear reactions induced by protons, deuterons, and alpha particles on phosphorus targets. When necessary, published experimental data are corrected, and, when possible, excitation functions are proposed

  20. Interaction of neutrons with alpha particles: A tribute to Heinz Barschall

    OpenAIRE

    Hoop, B. de

    2015-01-01

    As a tribute to our teacher and mentor on the occasion of his centennial celebration, we provide a brief historical overview and a summary of sustained interest in the topic of interaction of neutrons with alpha particles.

  1. Measurement of $\\alpha$-particle quenching in LAB based scintillator in independent small-scale experiments

    CERN Document Server

    von Krosigk, B; Hans, S; Junghans, A R; Kögler, T; Kraus, C; Kuckert, L; Liu, X; Nolte, R; O'Keeffe, H M; Tseung, H S Wan Chan; Wilson, J R; Wright, A; Yeh, M; Zuber, K

    2015-01-01

    The $\\alpha$-particle light response of liquid scintillators based on linear alkylbenzene (LAB) has been measured with three different experimental approaches. In the first approach, $\\alpha$-particles were produced in the scintillator via $^{12}$C($n$,$\\alpha$)$^9$Be reactions. In the second approach, the scintillator was loaded with 2% of $^{\\mathrm{nat}}$Sm providing an $\\alpha$-emitter, $^{147}$Sm, as an internal source. In the third approach, a scintillator flask was deployed into the water-filled SNO+ detector and the radioactive contaminants $^{222}$Rn, $^{218}$Po and $^{214}$Po provided the $\\alpha$-particle signal. The behavior of the observed $\\alpha$-particle light outputs are in agreement with each case successfully described by Birks' law. The resulting Birks parameter $kB$ ranges from $(0.0071\\pm0.0003)$ cm/MeV to $(0.0076\\pm0.0003)$ cm/MeV. In the first approach, the $\\alpha$-particle light response was measured simultaneously with the light response of recoil protons produced via neutron-proto...

  2. Fokker Planck kinetic modeling of suprathermal alpha-particles in a fusion plasma

    OpenAIRE

    Peigney, Benjamin-Edouard; Larroche, Olivier; Tikhonchuk, Vladimir

    2014-01-01

    We present an ion kinetic model describing the ignition and burn of the deuterium-tritium fuel of inertial fusion targets. The analysis of the underlying physical model enables us to develop efficient numerical methods to simulate the creation, transport and collisional relaxation of fusion reaction products (alpha-particles) at a kinetic level. A two-energy-scale approach leads to a self-consistent modeling of the coupling between suprathermal alpha-particles and the thermal bulk of the impl...

  3. Modification of thermal, optical and structural properties of bayfol nuclear track detector by alpha particles irradiation

    International Nuclear Information System (INIS)

    The effect of alpha particle dose on the thermal, optical and structural properties of Bayfol solid state nuclear track detector (SSNTD) was investigated. Non-isothermal studies were carried out using thermal gravimetric analysis (TGA) and differential thermal gravimetric (DTG) to obtain the activation energy of decomposition for Bayfol detector. Thermal gravimetric analysis (TGA) indicates that the Bayfol samples decompose in one main break down stage. Samples from 250 cm thickness sheets were exposed to alpha particles in the dose range 3.5-67.03 Gy. The variation of transition temperatures with the alpha particle dose has been determined using differential thermal analysis (DTA). The results indicate that the irradiation with alpha particles in the dose range 26.81-67.03 Gy decreases the melting temperature of the Bayfol samples and this is most suitable for applications requiring the molding of this polymer at lower temperatures. Also, the alpha particle dose gives advantage for increasing the correlation between melting temperatures and the amount of crystalline regions that is related to both cross-linking and degradation phenomena. In addition, optical and structural property studies using refractive index, IR spectroscopy, and x-ray diffraction measurements were performed on non irradiated and irradiated Bayfol samples. The results indicate that the anisotropic character, absorbance and the degree of ordering of the Bayfol polymer are dependent on the alpha particle dose

  4. Development of the MICROMEGAS Detector for Measuring the Energy Spectrum of Alpha Particles by using a 241-Am Source

    CERN Document Server

    Kim, Do Yoon; Shin, Jae Won; Park, Tae-Sun; Hong, Seung-Woo; Andriamonje, Samuel; Kadi, Yacine; Tenreiro, Claudio

    2016-01-01

    We have developed MICROMEGAS (MICRO MEsh GASeous) detectors for detecting {\\alpha} particles emitted from an 241-Am standard source. The voltage applied to the ionization region of the detector is optimized for stable operation at room temperature and atmospheric pressure. The energy of {\\alpha} particles from the 241-Am source can be varied by changing the flight path of the {\\alpha} particle from the 241 Am source. The channel numbers of the experimentally-measured pulse peak positions for different energies of the {\\alpha} particles are associated with the energies deposited by the alpha particles in the ionization region of the detector as calculated by using GEANT4 simulations; thus, the energy calibration of the MICROMEGAS detector for {\\alpha} particles is done. For the energy calibration, the thickness of the ionization region is adjusted so that {\\alpha} particles may completely stop in the ionization region and their kinetic energies are fully deposited in the region. The efficiency of our MICROMEGA...

  5. Coincidence techniques (time correlation) alpha-gamma particles associated experiments on PGFNAA

    International Nuclear Information System (INIS)

    PGFNAA (Prompt Gamma Fast Neutron Alpha Associated) techniques offers capabilities far beyond those of the conventional inspection system to detect hazardous materials such as explosives or drugs. This technique uses the time coincidence between alpha and gamma particles to reduce the background produced by fast neutron interactions not only with the objects but also with the surrounding material. This paper reports the experimental setup that have been conducted to capture coincident events between alpha and gamma particles. Although not perfect, but the reduction of the background almost 100 % had been obtained on the outside area of the spectrum energy interest for water and graphite samples. (author)

  6. Characterization of a alpha particle detector CR-39 exposed to a source of radium

    International Nuclear Information System (INIS)

    In this project, the main goal is the characterization of a alpha particle detector CR-39 exposed to a source of radio. Three detectors were exposed to a source of radium and then chemically treated for different periods. This way, we could analyze these samples and collect the information needed to verify that at least one of the chemical attack, there has been a separation of the energies alpha particles incident with distinct peaks, thus characterizing the CR-39 as alpha spectrometer in the range 2.5 to 6.3 MeV . (author)

  7. Calculations of alpha particle loss for reversed magnetic shear in the Tokamak Fusion Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Redi, M.H.; White, R.B.; Batha, S.H.; Levinton, F.M.; McCune, D.C.

    1997-03-01

    Hamiltonian coordinate, guiding center code calculations of the toroidal field ripple loss of alpha particles from a reversed shear plasma predict both total alpha losses and ripple diffusion losses to be greater than those from a comparable non-reversed magnetic shear plasma in the Tokamak Fusion Test Reactor (TFTR) [Fusion Technol. 21, 1324 (1992)]. High central q is found to increase alpha ripple losses as well as first orbit losses of alphas in the reversed shear simulations. A simple ripple loss model, benchmarked against the guiding center code, is found to work satisfactorily in transport analysis modelling of reversed and monotonic shear scenarios. Alpha ripple transport on TFTR affects ions within r/a=0.5, not at the plasma edge. The entire plasma is above threshold for stochastic ripple loss of alpha particles at birth energy in the reversed shear case simulated, so that all trapped 3.5 MeV alphas are lost stochastically or through prompt losses. The 40% alpha particle loss predictions for TFTR suggest that reduction of toroidal field ripple will be a critical issue in the design of a reversed shear fusion reactor.

  8. Downstream energetic proton and alpha particles during quasi-parallel interplanetary shock events

    Science.gov (United States)

    Tan, L. C.; Mason, G. M.; Gloeckler, G.; Ipavich, F. M.

    1988-01-01

    This paper considers the energetic particle populations in the downstream region of three quasi-parallel interplanetary shock events, which was explored using the ISEE 3 Ultra Low Energy Charge Analyzer sensor, which unambiguously identifies protons and alpha particles using the electrostatic deflection versus residual energy technique. The downstream particles were found to exhibit anisotropies due largely to convection in the solar wind. The spectral indices of the proton and the alpha-particle distribution functions were found to be remarkably constant during the downstream period, being generally insensitive to changes in particle flux levels, magnetic field direction, and solar wind densities. In two of the three events, the proton and the alpha spectra were the same throughout the entire downstream period, supporting the prediction of diffusive shock acceleration theory.

  9. Analysis of uncertainties in alpha-particle optical-potential assessment below the Coulomb barrier

    CERN Document Server

    Avrigeanu, V

    2016-01-01

    Background: Recent high-precision measurements of alpha-induced reaction data below the Coulomb barrier have pointed out questions of the alpha-particle optical-model potential (OMP) which are yet open within various mass ranges. Purpose: The applicability of a previous optical potential and eventual uncertainties and/or systematic errors of the OMP assessment at low energies can be further considered on this basis. Method: Nuclear model parameters based on the analysis of recent independent data, particularly gamma-ray strength functions, have been involved within statistical model calculation of the (alpha,x) reaction cross sections. Results: The above-mentioned potential provides a consistent description of the recent alpha-induced reaction data with no empirical rescaling factors of the and/or nucleon widths. Conclusions: A suitable assessment of alpha-particle optical potential below the Coulomb barrier should involve the statistical-model parameters beyond this potential on the basis of a former analysi...

  10. The modified Newton method for the solution of the inverse scattering problem with charged particles at fixed energy

    International Nuclear Information System (INIS)

    The modified Newton method, previously developed and used for neutral particle scattering, is extended for the solution of the inverse scattering problem with charged particles and applied to elastic nuclear heavy ion scattering. (orig.)

  11. Theoretical studies on bioaerosol particle size and shape measurement from spatial scattering profiles

    Institute of Scientific and Technical Information of China (English)

    Chunxia Feng; Lihua Huang; Jianbo Wang; Yongkai Zhao; Huijie Huang

    2011-01-01

    @@ A method of clarifying bioaerosol particles is proposed based on T-matrix.Size and shape characterizations are simultaneously acquired for individual bioaerosol particles by analyzing the spatial distribution of scattered light.The particle size can be determined according to the scattering intensity,while shape information can be obtained through asymmetry factor(AF).The azimuthal distribution of the scattered light for spherical particles is symmetrical,whereas it is asymmetrical for non-spherical ones,and the asymmetry becomes intense with increasing asphericity.The calculated results denote that the 50-100 scattering angle is an effective range to classify the bioaerosol particles that we axe concerned of.The method is very useful in real-time environmental monitoring of particle sizes and shapes.%A method of clarifying bioaerosol particles is proposed based on T-matrix. Size and shape characterizations are simultaneously acquired for individual bioaerosol particles by analyzing the spatial distribution of scattered light. The particle size can be determined according to the scattering intensity, while shape information can be obtained through asymmetry factor (AF). The azimuthal distribution of the scattered light for spherical particles is symmetrical, whereas it is asymmetrical for non-spherical ones, and the asymmetry becomes intense with increasing asphericity. The calculated results denote that the 5°-10° scattering angle is an effective range to classify the bioaerosol particles that we are concerned of. The method is very useful in real-time environmental monitoring of particle sizes and shapes.

  12. ICRF enhancement of fusion reactivity in the presence of alpha particles

    International Nuclear Information System (INIS)

    Absorption of ICRF (ion cyclotron range of frequency) waves by alpha particles and fusion reactivity enhancement due to the ICRF induced ion tail are investigated. The rate of linear absorption by alpha particles increases with the cyclotron harmonic number, and decreases with the ratio of the electron plasma frequency to the electron cyclotron frequency. The deformation of the distribution due to ICRF waves is also examined by using a solution to a Fokker-Planck equation combined with a quasi-linear RF (radiofrequency) diffusion term. It is found that second harmonic ICRF heating is comparatively applicable to the enhancement of the fusion power density even in the presence of alpha particles, while the efficiency of the enhancement is deteriorated markedly by wave deposition to alphas for higher harmonic ICRF heating in the high magnetic field. (author)

  13. Nuclear structure and reaction mechanisms studied on alpha-particle transitions

    International Nuclear Information System (INIS)

    Since the observation of the natural alpha decay of atomic nuclei the alpha particle was and is considered as an important component of the nuclear matter. The modern studies of alpha-particle transfer reactions are devoted to the question on four-particle correlations (alpha-particle clusters) generally in nuclear matter or also on nuclear surfaces. Thereby one is today yet absolutely far away from a unified picture of the mechanism of the alpha transfer: It is shown that different reaction and nuclear models must be used with different success for the interpretation of the data. Theoretical and experimental determination of spectroscopic strength distribution were thereby developed mutually supportingly each other. On the experimental side the question of the reaction mechanism and the determination of its details is to be clarified. Here approaches were developed which lead to a unified description in the sd shell. Calculations in the formalism of the coupled channels with spectroscopic factors calculated in the framework of the shell model lead to convincing agreements between theoretical and experimental angular distributions regarding both their shape and their amplitude. Hereby it was shown that beside the determination of the potential parameters a two-stage reaction mechanism as in an alpha-particle transition after or before an inelastic excitation of the target or residual nucleus is of decicive importance. (HSI)

  14. Comparison of Optical Models for 400 MeV alpha scattering off 90Zr and 92Mo

    Science.gov (United States)

    Jones, Daniel; Howard, Kevin; Garg, Umesh; Senyigit, Menekse

    2015-10-01

    Nuclear incompressibility is an important parameter governing the equation of state of nuclear matter. From the measurable centroid energies of the Isoscalar Giant Monopole Resonance (ISGMR), the incompressibility of nuclear matter can be calculated. The first necessary step is to fit elastic scattering angular distributions for a particular reaction and test the obtained model dependent parameters by calculating low-lying discrete state distributions for target nuclei. This study tests the suitability of two optical models to reproduce the angular distributions of differential cross sections from elastic and inelastic scattering of 400-MeV alpha particles. The first model utilizes a single folded potential for both the real and imaginary volume terms, and the second utilizes a single folded potential for the real volume term, and a phenomenological Woods-Saxon potential for the imaginary volume term. The elastic distributions for two heavy isotopes, 90Zr and 92Mo, are analyzed and the best parameter sets for each are shown. From this comparison, it is concluded that the second model, the so called ``hybrid model,'' is better able to reproduce the angular distributions for both 90Zr and 92Mo. Future work will include the Multipole Decomposition Analysis (MDA) for each reaction. NSF/REU Program at Notre Dame.

  15. Effects of alpha particle transport driven by Alfvenic instabilities on proposed burning plasma scenarios on ITER

    International Nuclear Information System (INIS)

    The consistency of proposed burning plasma scenarios with Alfvenic instabilities driven by alpha particles is investigated. If the alpha particle pressure is above the threshold for resonant excitation of Energetic Particle driven Modes (EPMs), significant modification of the alpha particle pressure profile can take place. Model simulations are performed using the Hybrid MHD-Gyrokinetic Code (HMGC) retaining relevant thermal-plasma parameters, safety factor and alpha particle pressure profiles. ITER monotonic-q and reversed-shear scenarios are considered. A 'hybrid' ITER scenario is also studied and quantitatively compared with the previous ones. We find that, unlike the latter, the former equilibria are unstable. Nonlinear effects on the alpha-particle pressure profile result, however, to be negligible for the monotonic-q case. They can instead be relevant for the reversed-shear scenario. The assessment of such a conclusion requires further investigations concerning the possibility that the strong EPM instability is regulated, in realistic conditions, by nonlinear effects of weaker Alfven modes. (author)

  16. Alfven Eigenmode And Ion Bernstein Wave Studies For Controlling Fusion Alpha Particles

    CERN Document Server

    Franklin, F R

    1999-01-01

    In magnetic confinement fusion reactor plasmas, the charged fusion products (such as alpha particles in deuterium-tritium plasmas) will be the dominant power source, and by controlling these charged fusion products using wave-particle interactions the reactor performance could be optimized. This thesis studies two candidate waves: Mode- Converted Ion Bernstein Waves (MCIBWs) and Alfvé n Eigenmodes (AEs). Rates of MCIBW-driven losses of alpha-like fast deuterons, previously observed in the Tokamak Fusion Test Reactor (TFTR), are reproduced by a new model so that the wave-particle diffusion coefficient can be deduced. The MCIBW power in TFTR is found to be ∼ 1/3 that needed for collisionless alpha particle control...

  17. Cell survival following alpha particle irradiation: critical sites and implications for carcinogenesis

    International Nuclear Information System (INIS)

    In experiments in which mammalian cells were irradiated with 5.6 MeV alpha particles from a Tandem Van de Graaff machine we have confirmed the finding of others that the mean lethal dose (D0) is about 100 rad, but by measurements of the area of the cell nuclei as irradiated we found that this mean lethal dose corresponds not to 1, as expected, but to about 27 alpha particles per cell nucleus. (The exact number appears to change slightly with cell passage number.) This allows for the possibility that the direct action of alpha particles on the nucleus may be the important event in carcinogenesis, a theory which was previously difficult to accept if a single particle hitting the nucleus anywhere was considered to be lethal. Evidence is presented to implicate the nucleolus as a possible critical site for the inhibition of reproductive integrity of the cell

  18. Scattering properties of the heterogeneous and non-spherical haze particles in the SWIR band

    International Nuclear Information System (INIS)

    To effectively estimate the influence of multiple scattering caused by haze particles on the misestimating of CO2 concentrations, it is necessary to understand the scattering properties of haze particles in the shortwave infrared (SWIR) wavelength range (∼1.6um) using satellite data. Due to the complexity of structures and components of haze particles, this paper investigates effects of particle size and chemical component on the scattering properties of both single non-spherical particles and aggregates for the 1.6um by using numerically effective medium theory and core-mantle theory. For the single non-spherical particles, the scattering parameters (e.g. scattering phase function, single scattering albedo, extinction coefficient and scattering coefficient) are calculated by combining the T-matrix method and the Maxwell-Garnett effective medium theory. For the aggregates, the particle-cluster aggregation algorithm is used to generate aggregates with different monomer numbers. And then, the Core-Mantle Generalized Multi-particle Mie (CMGMM) method is used to compute the scattering parameters. The results indicate that the scattering characteristics are significantly different for both single non-spherical particles and aggregates

  19. Alpha particle emitters in cancer therapy: establishing the rationale and overcoming the difficulties

    International Nuclear Information System (INIS)

    Full text: Once a tumor has metastasized, the possibility of cure is significantly diminished, if not excluded. Since metastatic spread arises due to the release of single tumor cells or tumor cell clusters, treatment regimens following an overt metastasis must include agents that eradicate individual tumor cells and cell clusters or that prevent their dissemination. Alpha particles may be highly effective in eradicating rapidly accessible disease. The effectiveness of alpha particles arises because the amount of energy deposited per unit distance traveled (linear energy transfer or LET) is approximately 400 times greater than that of beta particles (80 keV/μm vs. 0.2 keV/μm). Each traversal of an alpha particle through a cell nucleus results in a very highly ionizing track. Cell survival studies have shown that alpha-particle killing is independent of oxygenation state or cell-cycle during irradiation and that as few as 1 to 6 tracks across the nucleus may result in cell death. Most studies with alpha-particle emitting radionuclides for therapy have examined either bismuth-212 or astatine-211. Both radionuclides are short-lived with 61 minute and 7.2 hour half-lives, respectively, yielding intermediates with 3-minute and 32 year half-lives, respectively. Both emit alpha particles whose range is 40 to 80 μm. Alpha-particle emitting radionuclides have been attached to antibodies against tumor cell associated antigen. Antibodies have been the most widely used vehicle for delivery of alpha particles due to their specificity. Bismuth-212 has demonstrated a significant curative potential with minimal toxicity. In an ascites tumor mouse model, specific targeting and 80% cure following injection of Bi-212-labeled antibody has been observed (Macklis RM et al, Science, 240:1024-1026, 1988). It is important to define the realm of applicability for alpha particle emitting radionuclides. The short half-life of most currently available radionuclides, limits their use to

  20. The role of alpha particles in the dynamics of ring-stabilized devices

    International Nuclear Information System (INIS)

    The use of relativistic electron rings to stabilize plasmas against the interchange modes has been utilized in such devices as the Elmo Bumpy Torus (EBT) and the plugs of a Tandem Mirror device (STM). In the EBT case enhanced stability is reflected in higher betas (ratio of plasma to magnetic field pressures), while in the Tandem Mirror case symmetry in the plug magnetic geometry results in reduced particle diffusion across the magnetic field in the central cell. Regardless of the application, the question arises as to what effect would alpha particles generated by the Deuterium-Tritium (DT) reactions have on the stability of such ring-stabilized devices. In this paper the macroscopic stability of such systems is reexamined in order to assess the effect of alphas on the background interchange mode, the interacting interchange mode, and the high frequency compressional Alfven and coupled modes. A fluid description is used for the background plasma while a kinetic treatment is utilized for the hot electron species and alpha particles. It is shown that the alphas tend to mildly destabilize the interacting interchange while stabilizing the background interchange due to their sizeable Larmor radii. The destabilization is most pronounced at high alpha energies i.e., at birth, and near complete recovery of stability is achieved as these particles approach thermalization with the background ions. It is also shown that the alphas completely stabilize the high frequency modes. (orig.)

  1. Effect of alpha particles on the stability of Elmo Bumpy Torus (EBT) reactor. Final report

    International Nuclear Information System (INIS)

    The macroscopic stability of an ignited EBT reactor is investigated by studying the effects of the alpha particles generated by the Deuterium-Tritium (D-T) fusion reaction on the background interchange mode, the interacting interchange mode, and the high-frequency compressional Alfven and coupled modes. A fluid description is used for the background plasma while a kinetic treatment is utilized for the hot electron species and the alpha particles. It is shown that the alphas tend to mildly destabilize the interacting interchange while stabilizing the background interchange due to their sizable Larmor radii. The destabilization is most pronounced when the beta of the alpha particles in highest, i.e., at birth, and recovery of stabilization takes place as these particles slow down toward thermalization. It is also shown that the alphas completely stabilize the high frequency modes so that it can safely be concluded that fusion alphas present no detrimental effects on the stability of an EBT reactor that possesses an appropriate hot electron ring for macroscopic stability

  2. Formulation of alpha-particle condensation in the macroscopic limit

    International Nuclear Information System (INIS)

    Following closely BCS theory for pairs, an eventually viable theory for α-particle condensation (quartetting) is sketched. In the final formula the quartet wave function is replaced by a Slater determinant projected on good total momentum. The only variational field is then the single particle 0S wave function. This should reduce the numerical complexity to solve the quartet equations considerably. (author)

  3. Giant In-Particle Field Concentration and Fano Resonances at Light Scattering by High-Refractive Index Particles

    OpenAIRE

    Tribelsky, M. I.; Miroshnichenko, A. E.

    2015-01-01

    A detailed analytical inspection of light scattering by a particle with high refractive index m+i\\kappa and small dissipative constant \\kappa is presented. We have shown that there is a dramatic difference in the behavior of the electromagnetic field within the particle (inner problem) and the scattered field outside it (outer problem). With an increase in m at fix values of the other parameters, the field within the particle asymptotically converges to a periodic function of m. The electric ...

  4. Alpha particle destabilization of the toroidicity-induced Alfven eigenmodes

    International Nuclear Information System (INIS)

    The high frequency, low mode number toroidicity-induced Alfven eigenmodes (TAE) are shown to be driven unstable by the circulating and/or trapped α-particles through the wave-particle resonances. Satisfying the resonance condition requires that the α-particle birth speed vα ≥ vA/2|m-nq|, where vA is the Alfven speed, m is the poloidal model number, and n is the toroidal mode number. To destabilize the TAE modes, the inverse Landau damping associated with the α-particle pressure gradient free energy must overcome the velocity space Landau damping due to both the α-particles and the core electrons and ions. The growth rate was studied analytically with a perturbative formula derived from the quadratic dispersion relation, and numerically with the aid of the NOVA-K code. Stability criteria in terms of the α-particle beta βα, α-particle pressure gradient parameter (ω*/ωA) (ω* is the α-particle diamagnetic drift frequency), and (vα/vA) parameters will be presented for TFTR, CIT, and ITER tokamaks. The volume averaged α-particle beta threshold for TAE instability also depends sensitively on the core electron and ion temperature. Typically the volume averaged α-particle beta threshold is in the order of 10-4. Typical growth rates of the n=1 TAE mode can be in the order of 10-2ωA, where ωA=vA/qR. Other types of global Alfven waves are stable in D-T tokamaks due to toroidal coupling effects

  5. TCAD simulation for alpha-particle spectroscopy using SIC Schottky diode

    International Nuclear Information System (INIS)

    There is a growing requirement of alpha spectroscopy in the fields context of environmental radioactive contamination, nuclear waste management, site decommissioning and decontamination. Although silicon-based alpha-particle detection technology is mature, high leakage current, low displacement threshold and radiation hardness limits the operation of the detector in harsh environments. Silicon carbide (SiC) is considered to be excellent material for radiation detection application due to its high band gap, high displacement threshold and high thermal conductivity. In this report, an alpha-particle-induced electron-hole pair generation model for a reverse-biased n-type SiC Schottky diode has been proposed and verified using technology computer aided design (TCAD) simulations. First, the forward-biased I-V characteristics were studied to determine the diode ideality factor and compared with published experimental data. The ideality factor was found to be in the range of 1.4-1.7 for a corresponding temperature range of 300-500 K. Next, the energy-dependent, alpha-particle-induced EHP generation model parameters were optimised using transport of ions in matter (TRIM) simulation. Finally, the transient pulses generated due to alpha-particle bombardment were analysed for (1) different diode temperatures (300-500 K), (2) different incident alpha-particle energies (1-5 MeV), (3) different reverse bias voltages of the 4H-SiC-based Schottky diode (-50 to -250 V) and (4) different angles of incidence of the alpha particle (0 deg. -70 deg. ).The above model can be extended to other (wide band-gap semiconductor) device technologies useful for radiation-sensing application. (authors)

  6. Alpha-particle emission probabilities in the decay of {sup 240}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Sibbens, G., E-mail: goedele.sibbens@ec.europa.e [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel (Belgium); Pomme, S.; Altzitzoglou, T. [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel (Belgium); Garcia-Torano, E. [Laboratorio de Metrologia de Radiaciones Ionizantes, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Janssen, H.; Dersch, R.; Ott, O. [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Martin Sanchez, A. [Departamento de Fisica, Universidad de Extremadura, Badajoz, E-06071 (Spain); Rubio Montero, M.P. [Departamento de Fisica Aplicada, Universidad de Extremadura, Merida, Badajoz, E-06800 (Spain); Loidl, M. [Laboratoire National Henri Becquerel, LNE/CEA-LIST, 91191 Gif-sur-Yvette (France); Coron, N.; Marcillac, P. de [Institut d' Astrophysique Spatiale, CNRS, 91405 Orsay Campus (France); Semkow, T.M. [Wadsworth Center, New York State Department of Health, Albany, NY 12201 (United States)

    2010-07-15

    Sources of enriched {sup 240}Pu were prepared by vacuum evaporation on quartz substrates. High-resolution alpha-particle spectrometry of {sup 240}Pu was performed with high statistical accuracy using silicon detectors and with low statistical accuracy using a bolometer. The alpha-particle emission probabilities of six transitions were derived from the spectra and compared with literature values. Additionally, some alpha-particle emission probabilities were derived from {gamma}-ray intensity measurements with a high-purity germanium detector. The alpha-particle emission probabilities of the three main transitions at 5168.1, 5123.6 and 5021.2 keV were derived from seven aggregate spectra analysed with five different fit functions and the results were compatible with evaluated data. Two additional weak peaks at 4863.5 and 4492.0 keV were fitted separately, using the exponential of a polynomial function to represent the underlying tailing of the larger peaks. The peak at 4655 keV could not be detected by alpha-particle spectrometry, while {gamma}-ray spectrometry confirms that its intensity is much lower than expected from literature.

  7. Review of alpha-particle spectrometric measurements of actinides

    International Nuclear Information System (INIS)

    At present the silicon surface-barrier detector is the most used α-particle detector mainly due to its high energy resolution, excellent stability, low background and low cost. In this presentation various parameters of importance for α-particle spectrometry are discussed, i.e. energy resolution and interval selection, energy calibration, background and peak tailing. Examples of α-particle spectra recorded from various actinides (Th, U, Np, Pu, Am, and Cm) separated from environmental samples are shown, and the choice of yield determinants is discussed for each case. (author)

  8. Alpha particles spectrometer with photodiode PIN; Espectrometro de particulas alfa con fotodiodo PIN

    Energy Technology Data Exchange (ETDEWEB)

    Chacon R, A.; Hernandez V, R.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidades Academicas de Estudios Nucleares e Ingenieria Electrica, Calle Cipres No. 10, Fracc. La Penuela, 09869 Zacatecas (Mexico); Ramirez G, J. [Instituto Nacional de Estadistica Geografia e Informatica, Direccion General de Innovacion y Tecnologia de Informacion, Av. Heroes de Nacozari Sur 2301, Fracc. Jardines del Parque, 20276 Aguascalientes (Mexico)], e-mail: achruiz@hotmail.com

    2009-10-15

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  9. Effects of q(r) on the Alpha Particle Ripple Loss in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    D.S. Darrow; M. Diesso; R.V. Budny; S. Batha; S.J. Zweben; et al.

    1997-09-01

    An experiment was done with TFTR DT plasmas to determine the effect of the q(r) profile on the alpha particle ripple loss to the outer midplane. The alpha particle loss measurements were made using a radially movable scintillator detector 20 degrees below the outer midplane. The experimental results were compared with TF ripple loss calculations done using a Monte Carlo guiding center orbit following code, ORBIT. Although some of the experimental results are consistent with the ORBIT code modeling, the variation of the alpha loss with the q(r) profiles is not well explained by this code. Quantitative interpretation of these measurements requires a careful analysis of the limiter shadowing effect, which strongly determines the diffusion of alphas into the detector aperture.

  10. The Structure of Nuclei Joint Analysis of Elastic, Inelastic Scattering and Total Reactions Cross-Sections for ^{90,94}Zr-Particles Data

    CERN Document Server

    Duysebaev, A D; Kuchtina, I N; Sadykov, B M; Slusarenko, L I; Tokarevsky, V V; Fayans, S A

    2001-01-01

    A complex analysis of experimental data of elastic, inelastic scattering and total reactions cross-sections of alpha-particles on ^{90,94}Zr nuclei is performed. Values of the deformation lengths and neutron-proton multipole matrix elements relations for 2_{1}^{+}- and 3_{1}^{+}-states of ^{90,92,94,96}Zr nuclei for different types of particles are obtained. A comparative analysis is made. Experimental data for inelastic scattering of 35.4, 40.0, 50.1 and 65.0 MeV alpha-particles on ^{90,94}Zr nuclei are analysed for understanding the phase shifts in frames of the unified approach.

  11. Estimation of scattering from a moist rough surface with spheroidal dust particles

    Indian Academy of Sciences (India)

    Mukesh Kumar

    2009-08-01

    The scattering from moisture rough surface with spheroidal dust particles having surface with spheroidal dust particles has recently received much attention. In part due to the recent prediction and observation of the spheroidal dust particles in rough surfaces under elastic wave by the Kirchhoff scattering model and scalar approximation with slope. Our analysis shows that the scattering depends on the moisture (2–4.5%) with spheroidal dust particles. At slightly moisture rough surface the dielectric properties increase with change in field amplitude in a rough surface with spheroidal dust particles.

  12. Intermediate regime of charged particle scattering in the field-reversal configuration

    Energy Technology Data Exchange (ETDEWEB)

    Shustov, P. I., E-mail: p.shustov@gmail.com; Yushkov, E. V. [Space Research Institute, RAS, Profsouznaya st., 84/32, GSP-7, 117997 Moscow (Russian Federation); Department of Physics, Moscow State University, 119992 Moscow (Russian Federation); Artemyev, A. V., E-mail: artemyev@iki.rssi.ru [Space Research Institute, RAS, Profsouznaya st., 84/32, GSP-7, 117997 Moscow (Russian Federation)

    2015-12-15

    In this paper, we investigate the charged particle scattering in the magnetic field configuration with stretched magnetic field lines. This scattering results from the violation of the adiabaticity of charged particle motion in the region with the strong gradient of the magnetic field. We consider the intermediate regime of charged particle dynamics, when the violation of the adiabaticity is significant enough, but particle motion is not chaotic. We demonstrate and describe the significant scattering of particles with large adiabatic invariants (magnetic moment). We discuss a possible application of obtained results for description of the peculiarities of pitch-angle diffusion of relativistic electrons in the Earth radiation belts.

  13. First correlated measurements of the shape and scattering properties of cloud particles using the new Particle Habit Imaging and Polar Scattering (PHIPS probe

    Directory of Open Access Journals (Sweden)

    A. Abdelmonem

    2011-05-01

    Full Text Available Studying the radiative impact of cirrus clouds requires the knowledge of the link between their microphysics and the single scattering properties of the cloud particles. Usually, this link is created by modeling the optical scattering properties from in situ measurements of ice crystal size distributions. The measured size distribution and the assumed particle shape might be erroneous in case of non-spherical ice particles. We present here a novel optical sensor (the Particle Habit Imaging and Polar Scattering probe, PHIPS designed to measure the 3-D morphology and the corresponding optical and microphysical parameters of individual cloud particles, simultaneously. Clouds containing particles ranging in size from a few micrometers to about 800 μm diameter can be systematically characterized with an optical resolution power of 2 μm and polar scattering resolution of 1° for forward scattering directions (from 1° to 10° and 8° for side and backscattering directions (from 18° to 170°. The maximum acquisition rates for scattering phase functions and images are 262 KHz and 10 Hz, respectively. Some preliminary results collected in two ice cloud campaigns which were conducted in the AIDA cloud simulation chamber are presented. PHIPS showed reliability in operation and produced comparable size distributions and images to those given by other certified cloud particles instruments. A 3-D model of a hexagonal ice plate is constructed and the corresponding scattering phase function is compared to that modeled using the Ray Tracing with Diffraction on Facets (RTDF program. PHIPS is candidate to be a novel air borne optical sensor for studying the radiative impact of cirrus clouds and correlating the particle habit-scattering properties which will serve as a reference for other single, or multi-independent, measurements instruments.

  14. First correlated measurements of the shape and light scattering properties of cloud particles using the new Particle Habit Imaging and Polar Scattering (PHIPS probe

    Directory of Open Access Journals (Sweden)

    A. Abdelmonem

    2011-10-01

    Full Text Available Studying the radiative impact of cirrus clouds requires knowledge of the relationship between their microphysics and the single scattering properties of cloud particles. Usually, this relationship is obtained by modeling the optical scattering properties from in situ measurements of ice crystal size distributions. The measured size distribution and the assumed particle shape might be erroneous in case of non-spherical ice particles. We present here a novel optical sensor (the Particle Habit Imaging and Polar Scattering probe, PHIPS designed to measure simultaneously the 3-D morphology and the corresponding optical and microphysical parameters of individual cloud particles. Clouds containing particles ranging from a few micrometers to about 800 μm diameter in size can be characterized systematically with an optical resolution power of 2 μm and polar scattering resolution of 1° for forward scattering directions (from 1° to 10° and 8° for side and backscattering directions (from 18° to 170°. The maximum acquisition rates for scattering phase functions and images are 262 KHz and 10 Hz, respectively. Some preliminary results collected in two ice cloud campaigns conducted in the AIDA cloud simulation chamber are presented. PHIPS showed reliability in operation and produced size distributions and images comparable to those given by other certified cloud particles instruments. A 3-D model of a hexagonal ice plate is constructed and the corresponding scattering phase function is compared to that modeled using the Ray Tracing with Diffraction on Facets (RTDF program. PHIPS is a highly promising novel airborne optical sensor for studying the radiative impact of cirrus clouds and correlating the particle habit-scattering properties which will serve as a reference for other single, or multi-independent, measurement instruments.

  15. Monte Carlo nanodosimetry of alpha particle passages through the capillary endothelial nucleus application to systemic Targeted Alpha Therapy

    International Nuclear Information System (INIS)

    Full text: The biological effects of Targeted Alpha Therapy are strongly affected by the heterogeneous specific energy delivered to tumor cells. For systemic Targeted Alpha Therapy, all blood vessels inevitably received a background radiation from non-targeted decays with the blood circulation. The Geant4 Monte Carlo code was adapted to simulate the spatial non-uniform distribution of the alpha emitting radioisotope sources 213Bi, 212Bi and 211At. A cylindrical annulus was taken as a geometrical model to approximate the capillary. The endothelial cell nucleus was set to be an ellipsoid filled with liquid water to simulate nanometric target volumes at unit density. The Geant4 Low Energy physics model, based on the Livermore approach, was selected to model the particle interactions with the material in the experimental setup. The threshold of production of secondary particles was 7 eV. We validated the program with published results using spheroid cell geometry. The specific energy deposited in a capillary endothelial cell nucleus per radioactive decay and the capillary endothelial cell survival rates were calculated for the source constrained in the capillary lumen or the source binding to the surface antigen on the perivascular cancer cells. The measurement of nanodosimetric event size spectra based on simulated nanodosimetric data is presented. The value and limitations of this approach are discussed. (author)

  16. Alpha-particle clustering in excited expanding self-conjugate nuclei

    CERN Document Server

    Borderie, B; Ademard, G; Rivet, M F; De Filippo, E; Geraci, E; Neindre, N Le; Cardella, G; Lanzalone, G; Lombardo, I; Lopez, O; Maiolino, C; Pagano, A; Pirrone, S; Politi, G; Rizzo, F; Russotto, P

    2016-01-01

    The fragmentation of quasi-projectiles from the nuclear reaction 40Ca + 12C at 25 MeV/nucleon was used to produce alpha-emission sources. From a careful selection of these sources provided by a complete detection and from comparisons with models of sequential and simultaneous decays, strong indications in favour of $\\alpha$-particle clustering in excited 16O, 20Ne and 24}Mg are reported.

  17. Energetic/alpha particle effects on MHD modes and transport

    International Nuclear Information System (INIS)

    A nonvariational kinetic-MHD stability code (NOVA-K) has been employed to study TAE stability in TFRR D-T and DIII-D experiments and to achieve understanding of TAE instability drive and damping mechanism. Reasonably good agreement between theory and experiment has been obtained. In these experiments the dominant damping mechanism is due to both the thermal ion Landau damping and/or the beam ion Landau damping. Based on ITER EDA parameters, the TAE modes are expected to be unstable in normal ITER operations. Energetic particle transport has been studied using a test particle code (ORBIT). Energetic particle loss scales linearly with the TAE mode amplitude and can be large for TFRR and DIII-D for δBr/B > 10-4 due to large banana orbit. From quasi-linear (ORBIT) and nonlinear kinetic-MHD (MH3D-K) simulations the saturation of TAE modes is due to nonlinear wave particle trapping and energetic particle profile modification in both radial and energy space. Finally, a convective bucket transport mechanism by MHD waves with time-dependent frequency is presented. Based on the energy-selective characteristics of the bucket transport mechanism, undesirable particles such as helium ash can be removed from the plasma core efficiently

  18. [Particle Size and Number Density Online Analysis for Particle Suspension with Polarization-Differentiation Elastic Light Scattering Spectroscopy].

    Science.gov (United States)

    Chen, Wei-kang; Fang, Hui

    2016-03-01

    The basic principle of polarization-differentiation elastic light scattering spectroscopy based techniques is that under the linear polarized light incidence, the singlely scattered light from the superficial biological tissue and diffusively scattered light from the deep tissue can be separated according to the difference of polarization characteristics. The novel point of the paper is to apply this method to the detection of particle suspension and, to realize the simultaneous measurement of its particle size and number density in its natural status. We design and build a coaxial cage optical system, and measure the backscatter signal at a specified angle from a polystyrene microsphere suspension. By controlling the polarization direction of incident light with a linear polarizer and adjusting the polarization direction of collected light with another linear polarizer, we obtain the parallel polarized elastic light scattering spectrum and cross polarized elastic light scattering spectrum. The difference between the two is the differential polarized elastic light scattering spectrum which include only the single scattering information of the particles. We thus compare this spectrum to the Mie scattering calculation and extract the particle size. We then also analyze the cross polarized elastic light scattering spectrum by applying the particle size already extracted. The analysis is based on the approximate expressions taking account of light diffusing, from which we are able to obtain the number density of the particle suspension. We compare our experimental outcomes with the manufacturer-provided values and further analyze the influence of the particle diameter standard deviation on the number density extraction, by which we finally verify the experimental method. The potential applications of the method include the on-line particle quality monitoring for particle manufacture as well as the fat and protein density detection of milk products. PMID:27400522

  19. The 1997 IAEA intercomparison of commercially available PC-based software for alpha-particle spectrometry

    CERN Document Server

    Blaauw, M; Woods, S; Fazinic, S

    1999-01-01

    Four commercially available, PC-based analysis programs for alpha-particle spectrometry were compared using the 1997 IAEA test spectra, i.e. AlphaVision 1.20 (EG and G Ortec, USA), Alps 4.21 (Westmeier GmbH, Germany), Winner Alpha 4.0f5 (Eurisys Mesures, France) and Genie-2000 (Canberra Industries Inc., USA). A systematic statistical study of the analysis results was performed based on z-scores. The results indicate that the four programs leave room for substantial improvement.

  20. Emission of alpha particles and other light nuclei as a fission process

    International Nuclear Information System (INIS)

    The fission theory was successfully applied to the emission of alpha particles and other light nuclei from a heavy nucleus. Good agreement (within +-0.8 orders of magnitude) of the theoretical life times with experimental ones over a range of 24 orders of magnitude, was obtained. Three macroscopic models have been extended for the nuclear systems with different charge densities. A phenomenological shell correction was introduced. WKB approximation was used. By taking into account the nuclear deformation, the life-time of the alpha decay from a shape isomeric state was predicted. A new semiempirical relationship for the alpha decay life-time was derived. (author)

  1. An application of 222Rn alpha particle's tracks to uranium exploration

    International Nuclear Information System (INIS)

    The uranium exploration method is based on the register of 222Rn alpha particles; 222Rn gas is generated in the chain 238U desintegration. The detection of alpha particles was performed with cellulose nitrate films (NTC), located in a grid at the region in study. The alpha particles produce latent tracks in the NTC films; these tracks may be enlarged by chemical etching and are observed with an ordinary optic microscope, ninety seven NTC films were used, these were distributed in an area of approximately seventeen square kilometers, located in the municipalities of Granados and Huasabas in Sonora Mexico, the detectors remain in the ground for a thirty days mean period. The results obtained show an area with high 222Rn concentration, this can be related with an underground uranium ore deposit. The more important conclusion is that the results obtained in this work can be used as preliminary results for other prospection methods in this particular area. (author)

  2. Ripple Loss of Alpha Particles in a Low-Aspect-Ratio Tokamak Reactor

    International Nuclear Information System (INIS)

    Studies on the loss of alpha particles enhanced by toroidal field (TF) ripple in a low-aspect-ratio tokamak reactor (VECTOR) have been made by using an orbit-following Monte-Carlo code. In actual TF coil systems, the ripple loss of alpha particles is strongly reduced as the aspect ratio becomes low (the power loss ∝ A8.8 for A≥2.5) and the reduction of the number of TF coils results in a large amount of ripple loss even in a low-aspect-ratio tokamak. To reduce the number of TF coils from 12 to 6, about 40% of coil size enlargement is necessary in VECTOR. Ferrite plates are very effective to reduce ripple losses of alpha particles. By using ferrite plates, the coil size enlargement for N=6 can be relaxed to 15% and the number of coils can be reduced from 12 to 8 without enlargement of coil size in VECTOR. (author)

  3. High resolution alpha particle detectors based on 4H-SiC epitaxial layer

    International Nuclear Information System (INIS)

    We fabricated and characterized 4H-SiC Schottky diodes as a spectrometric detector of alpha particles. A thin blocking contact of Ni/Au (15 nm) was used to minimize the influence on alpha particles energy. Current-voltage characteristics of the detector were measured and a low current density below 0.3 nAcm−2 was observed at room temperature. 239Pu241Am244Cm was used as a source of alpha particles within the energy range between 5.1 MeV and 5.8 MeV for detector testing. The charge collection efficiency close to 100 % at reverse bias exceeding 50 V was determined. The best spectrometric performance shows a pulse height spectrum at a reverse bias of 200 V giving an energy resolution of 0.25 % in the full width and half maximum for 5.486 MeV of 241Am

  4. Alpha particle induced DNA damage and repair in normal cultured thyrocytes of different proliferation status

    DEFF Research Database (Denmark)

    Lyckesvärd, Madeleine Nordén; Delle, Ulla; Kahu, Helena;

    2014-01-01

    Childhood exposure to ionizing radiation increases the risk of developing thyroid cancer later in life and this is suggested to be due to higher proliferation of the young thyroid. The interest of using high-LET alpha particles from Astatine-211 ((211)At), concentrated in the thyroid by the same...... levels of γH2AX decreased during the first 24h in both cycling and stationary cultures and complete repair was seen in all cultures but cycling cells exposed to (211)At. Compared to stationary cells alpha particles were more harmful for cycling cultures, an effect also seen at the pChk2 levels...... cultures at a modest level of damage, clearly demonstrating that cell cycle status influences the relative effectiveness of alpha particles....

  5. Intrinsic efficiency of LR-115 in alpha particles detection: simulations and experiments

    International Nuclear Information System (INIS)

    A numerical simulation is developed to characterize the response of the cellulose nitrate detector ''LR-115 type II'' to alpha particles of different incidence angles and energies. It permits to know whether an alpha particle at a given energy and direction is able to produce a visible etched track or not. For this purpose, a Vt-variable track etch rate model is used. We have considered that the track etch rate is a function of the ionization rate and the defect created by delta rays along the alpha particle trajectory. Validation of the model is presented in the form of comparisons between theoretically computed values of the sensitive energy range and the track diameters and experimentally determined ones

  6. Alpha-particle confinement control of the geodesic winding of LHD-type fusion reactors

    International Nuclear Information System (INIS)

    It is calculated that the geodesic winding D-shaped helical magnetic field configuration can actively control the confinement and exhaust of alpha particles. A trapped particle orbit diagram (TPOD), which shows the presence of re-entering particles and specifies the loss-cone depth, is obtained from the deeply trapped particle orbits in a helical mirror magnetic field. The loss-cone depth becomes shallow when the magnetic axis is shifted to the inner side. On the other hand, the loss-cone depth can reach to the magnetic axis when the magnetic axis is shifted fairly to the outer side. Active control of the confinement and exhaust of 3.52 MeV alpha particles by controlling the magnetic axis position is also confirmed by collisionless orbit calculations. (author)

  7. Preliminary Study of Natural Alpha Particle Track Areal Distribution Behind Eyeglasses Obstacles

    International Nuclear Information System (INIS)

    Plastic nuclear track detectors are widely used to register tracks of alpha particles emitted from radon gas nuclei and radioactive daughter nuclei. Eye glasses, finger rings, necklaces and many other accessories intimately accompany most people. The eyeglasses may modify the surface distribution of alpha particle pass spots just behind them. There may be some effects due to the earth's magnetic field on the motion of the charged alpha particle emitters (radon ions). In metallic frames of the eyeglasses, the earth's magnetic field and charged radio-ions enforce free electrons to move setting electric current, which reduces the magnetic field at the frame. Being weak at the frame and stronger on both sides away, the magnetic field lines may form a magnetic trap of some charged radio-ions in the air. The polymer Solid State Nuclear Track Detector (SSNTD) CR-39 which is a polyalyl diglycol carbonate is used to register alpha particles behind the eyeglasses obstacles. Remarkable decrease in alpha track density was noticed in CR-39 registration due both to glass and magnetic screening. The obtained results call for more studies on all metallic tools used or possessed in mines and non-ventilated underground cavities.

  8. Stochastic loss of alpha particles in a Helias reactor

    International Nuclear Information System (INIS)

    It is shown that collisionless orbit transformation of the locally trapped particles to the locally passing ones and vice versa in the Wendelstein-line optimized stellarators results in stochastic diffusion of energetic ions. This diffusion can lead to the loss of an essential fraction of energetic ion population from the region where the characteristic diffusion time is small compared to the slowing down time. The loss region and the magnitude of the loss can be minimized by shaping the plasma temperature and density profiles so that they satisfy certain requirements. The predictions of the developed theory are in agreement with the results of numerical modelling of confinement of α-particles in a Helias reactor, which was carried out in this work with the use of the orbit following code. The considered diffusion seems to represent the dominant mechanism of classical losses of α-particles in a Helias reactor. (author)

  9. Finite-difference time domain solution of light scattering by arbitrarily shaped particles and surfaces

    DEFF Research Database (Denmark)

    Tanev, Stoyan; Sun, Wenbo

    2012-01-01

    for particle and surface scattering calculations and the uniaxial perfectly matched layer (UPML) absorbing boundary conditions for truncation of the FDTD grid. We show that the FDTD approach has a significant potential for studying the light scattering by cloud, dust, and biological particles. The...

  10. Applying alpha particle background ionization device in the development of pulsed nitrogen laser technology

    International Nuclear Information System (INIS)

    An investigation on the application of alpha particles in the induction of a bias ionized background plasma before, during and after the discharge of the N2 TE UV laser (337.1 nm), built in the LEL-IF/UFF is presented. The alpha particles are provided by Americium (241-Am) stripes placed inside the discharge channel of the laser device. The stimulated radiation output characteristics, in terms of gas pressure, charging voltage and pulse width, of a N2 TE UV laser (337.1 nm) circuit are presented. The increased laser yield is interpreted qualitatively through plasma impedance in the discharge circuit. (author)

  11. Applying alpha particle background ionization device in the development of pulsed nitrogen laser technology

    Energy Technology Data Exchange (ETDEWEB)

    Fellows, C.E.; Rodegheri, C.C.; Tauber, U. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Fisica. Lab. de Espectroscopia e Laser (LEL); Guterres, R.F. [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil). Coordenacao de Instalacoes Radiativas]. E-mail: rgutterr@cnen.gov.br

    2005-11-15

    An investigation on the application of alpha particles in the induction of a bias ionized background plasma before, during and after the discharge of the N2 TE UV laser (337.1 nm), built in the LEL-IF/UFF is presented. The alpha particles are provided by Americium (241-Am) stripes placed inside the discharge channel of the laser device. The stimulated radiation output characteristics, in terms of gas pressure, charging voltage and pulse width, of a N2 TE UV laser (337.1 nm) circuit are presented. The increased laser yield is interpreted qualitatively through plasma impedance in the discharge circuit. (author)

  12. The threshold states in the frame of the model of binding alpha particles

    International Nuclear Information System (INIS)

    A model of nuclear matter built from alpha-particles is proposed. In this model, nuclei possess the molecular structure. Analyzing the numbers of bonds, one gets the formula for the binding energy of a nucleus. The structure is determined by the minimum of the total potential energy, where interaction between alpha-particles is pairwise. The calculated binding energies show a good agreement with experiment. According to this model we can estimate the energy of Bose-Condensation for the 4N nuclei

  13. Preparation and preclinical evaluation of {sup 211}At-labelled compounds for {alpha}-particle radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, R.H.

    1994-12-31

    The interest for {alpha}-particle emitters in internal radiotherapy is increasing due to improved conjugation chemistry. Experimental work has concentrated on {sup 211}At and {sup 212}Bi since these to nuclides have radiochemical and physical properties suitable for medical application. In this report it is demonstrated that biologically active {sup 211}At-labelled compounds can be prepared within a relatively short time allowing utilization of this 7.2 h {alpha}-particle. It is further shown that {sup 211}At-TP-3 treatment of human osteosarcoma in vitro gives promising therapeutic ratios. 76 refs., 5 figs., 3 tabs.

  14. Magnetic Dynamics of Fine Particles Studied by Inelastic Neutron Scattering

    DEFF Research Database (Denmark)

    Hansen, Mikkel Fougt; Bødker, Franz; Mørup, Steen;

    2000-01-01

    We give an introduction to inelastic neutron scattering and the dynamic scattering function for magnetic nanoparticles. Differences between ferromagnetic and antiferromagnetic nanoparticles are discussed and we give a review of recent results on ferromagnetic Fe nanoparticles and canted...

  15. O({alpha}{sub s}) heavy flavor corrections to charged current deep-inelastic scattering in Mellin space

    Energy Technology Data Exchange (ETDEWEB)

    Bluemlein, J.; Hasselhuhn, A.; Kovacikova, P.; Moch, S.

    2011-04-15

    We provide a fast and precise Mellin-space implementation of the O({alpha}{sub s}) heavy flavor Wilson coefficients for charged current deep inelastic scattering processes. They are of importance for the extraction of the strange quark distribution in neutrino-nucleon scattering and the QCD analyses of the HERA charged current data. Errors in the literature are corrected. We also discuss a series of more general parton parameterizations in Mellin space. (orig.)

  16. Spin 1 inversion a Majorana tensor force for deuteron alpha scattering

    CERN Document Server

    Cooper, S G; MacIntosh, R S; Pomerantsev, V N

    1999-01-01

    We demonstrate, for the first time, successful S-matrix to potential inversion for spin one projectiles with non-diagonal $S^j_{ll'}$ yielding a $T_{\\rm R}$ interaction. The method is a generalization of the iterative-perturbative, IP, method. We present a test case indicating the degree of uniqueness of the potential. The method is adapted, using established procedures, into direct observable to potential inversion, fitting $\\sigma$, ${\\rm i}T_{11}$, $T_{20}$, $T_{21}$ and $T_{22}$ for d + alpha scattering over a range of energies near 10 MeV. The $T_{\\rm R}$ interaction which we find is very different from that proposed elsewhere, both real and imaginary parts being very different for odd and even parity channels.

  17. Measurement of the light scattering of single micrometer-sized particles captured with a microfluidic trap.

    Science.gov (United States)

    Dai, Jie; Li, Wei; Gong, Baoyu; Wang, Huimin; Xia, Min; Yang, Kecheng

    2015-11-16

    Light scattering detection of a single particle is significant to both theoretical developments and application progresses of particle scattering. In this work, a new method employing the polydimethylsiloxane microfluidic catcher with self-regulation was developed to detect the light scattering of an individual micro particle (20.42, 23.75, and 31.10 μm) in a wide angular range. This system can rapidly (particles without aggregations and continuously analyze its light scattering ranging from 2° to 162°. The high success ratio of the capture, good agreement with the anticipation, and moderate time and cost make this method a promising candidate in single-particle-scattering applications. PMID:26698501

  18. Order \\alpha_s^2 Contributions to charm production in charged-current deep-inelastic lepton-hadron scattering

    OpenAIRE

    Buza, M.; van Neerven, W. L.

    1997-01-01

    The most important part of the order $\\alpha_s^2$ corrections to the charm component of the charged-current structure functions $F_2(x,Q^2)$ and $F_3(x,Q^2)$ have been calculated. This calculation is based on the asymptotic form of the heavy-quark coefficient functions corresponding to the higher order corrections to the W-boson-gluon fusion process. These coefficient functions which are in principle only valid for $Q^2 \\gg m^2$ can be also used to estimate the order $\\alpha_s^2$ contribution...

  19. Natural protection from zoonosis by alpha-gal epitopes on virus particles in xenotransmission.

    Science.gov (United States)

    Kim, Na Young; Jung, Woon-Won; Oh, Yu-Kyung; Chun, Taehoon; Park, Hong-Yang; Lee, Hoon-Taek; Han, In-Kwon; Yang, Jai Myung; Kim, Young Bong

    2007-03-01

    Clinical transplantation has become one of the preferred treatments for end-stage organ failure, and one of the novel approaches being pursued to overcome the limited supply of human organs involves the use of organs from other species. The pig appears to be a near ideal animal due to proximity to humans, domestication, and ability to procreate. The presence of Gal-alpha1,3-Gal residues on the surfaces of pig cells is a major immunological obstacle to xenotransplantation. Alpha1,3galactosyltransferase (alpha1,3GT) catalyzes the synthesis of Gal alpha 1-3Gal beta 1-4GlcNAc-R (alpha-gal epitope) on the glycoproteins and glycolipids of non-primate mammals, but this does not occur in humans. Moreover, the alpha-gal epitope causes hyperacute rejection of pig organs in humans, and thus, the elimination of this antigen from pig tissues is highly desirable. Recently, concerns have been raised that the risk of virus transmission from such pigs may be increased due to the absence of alpha-gal on their viral particles. In this study, transgenic cells expressing alpha1,3GT were selected using 1.25 mg/ml neomycin. The development of HeLa cells expressing alpha1,3GT now allows accurate studies to be conducted on the function of the alpha-gal epitope in xenotransmission. The expressions of alpha-gal epitopes on HeLa/alpha-gal cells were demonstrated by flow cytometry and confocal microscopy using cells stained with IB4-fluorescein isothiocyanate lectin. Vaccinia viruses propagated in HeLa/alpha-gal cells also expressed alpha-gal on their viral envelopes and were more sensitive to inactivation by human sera than vaccinia virus propagated in HeLa cells. Moreover, neutralization of vaccinia virus was inhibited in human serum by 10 mm ethylene glycol bis(beta-aminoethylether)tetraacetic acid (EDTA) treatment. Our data indicated that alpha-gal epitopes are one of the major barriers to zoonosis via xenotransmission. PMID:17381684

  20. Probing the isoscalar excitations of 12C with inelastic alpha scattering

    International Nuclear Information System (INIS)

    The robust (spin and isospin zero) α-particle remains one of the best projectiles to probe the nuclear isoscalar excitations. In the present work, a microscopic folding model analysis of the α+12C inelastic scattering to the 2+ (4.44 MeV), 0+ (7.65 MeV), 3- (9.64 MeV), 0+ (10.3 MeV) and 1- (10.84 MeV) states in 12C has been performed using the 3-α resonating group method wave functions. The isoscalar transition strengths of these states were carefully studied based on the coupled-channel analysis using the microscopic folded form factors. A correlation between the weak binding and/or short lifetime of the excited state and absorption in the exit channel of inelastic scattering has been established. (author)

  1. Mie scattering analog in graphene: Lensing, particle confinement, and depletion of Klein tunneling

    Science.gov (United States)

    Heinisch, R. L.; Bronold, F. X.; Fehske, H.

    2013-04-01

    Guided by the analogy to Mie scattering of light on small particles, we show that the propagation of a Dirac-electron wave in graphene can be manipulated by a circular gated region acting as a quantum dot. Large dots enable electron lensing, while for smaller dots resonant scattering entails electron confinement in quasibound states. Forward scattering and Klein tunneling can be almost switched off for small dots by a Fano resonance arising from the interference between resonant scattering and the background partition.

  2. Mie scattering analog in graphene: lensing, particle confinement, and depletion of Klein tunneling

    OpenAIRE

    Heinisch, R. L.; Bronold, F. X.; Fehske, H.

    2013-01-01

    Guided by the analogy to Mie scattering of light on small particles we show that the propagation of a Dirac-electron wave in graphene can be manipulated by a circular gated region acting as a quatum dot. Large dots enable electron lensing, while for smaller dots resonant scattering entails electron confinement in quasibound states. Forward scattering and Klein tunneling can be almost switched off for small dots by a Fano resonance arising from the interference between resonant scattering and ...

  3. Light scattering by Gaussian random ellipsoid particles: First results with discrete-dipole approximation

    International Nuclear Information System (INIS)

    We introduce the stochastic geometry of a Gaussian random ellipsoid (GE) and, with the discrete-dipole approximation, carry out preliminary computations for light scattering by wavelength-scale GE particles. In the GE geometry, we describe the base ellipsoid by the three semiaxes a≥b≥c. The axial ratios b:a and c:a appear as two shape parameters additional to those of the Gaussian random sphere geometry (GS). We compare the scattering characteristics of GE particles to those of ellipsoids. Introducing irregularities on ellipsoids smoothens the angular scattering characteristics, in a way analogous to the smoothening of spherical particle characteristics in the case of GS particles.

  4. Correlations of $\\alpha$-particles in splitting of $^{12}$C nuclei by neutrons of energy of 14.1 MeV

    CERN Document Server

    Kattabekov, R R; Artemenkov, D A; Bradnova, V; Zarubin, P I; Zarubina, I G; Majling, L; Rusakova, V V; Sadovsky, A B

    2014-01-01

    Correlations of $\\alpha$-particles are studied on statistics of 400 events of splitting $^{12}$C $\\rightarrow$ 3$\\alpha$ in nuclear track emulsion exposed to $14.1 MeV$ neutrons. The ranges and emission angles of the $\\alpha$-particles are measured. Distributions over energy of $\\alpha$-particle pairs and triples are obtained.

  5. Nuclear reactions induced by high-energy alpha particles

    Science.gov (United States)

    Shen, B. S. P.

    1974-01-01

    Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

  6. Alpha-particle momentum distributions from 12C decaying resonances

    International Nuclear Information System (INIS)

    The computed α particle momentum distributions from the decay of low-lying 12C resonances are shown. The wave function of the decaying fragments is computed by means of the complex scaled hyperspherical adiabatic expansion method. The large-distance part of the wave functions is crucial and has to be accurately calculated. We discuss energy distributions, angular distributions and Dalitz plots for the 4+, 1+ and 4- states of 12C. (author)

  7. Alpha Particles Induce Apoptosis through the Sphingomyelin Pathway

    OpenAIRE

    Seideman, Jonathan H.; Stancevic, Branka; Rotolo, Jimmy A.; McDevitt, Michael R.; Howell, Roger W.; Kolesnick, Richard N; Scheinberg, David A.

    2011-01-01

    The sphingomyelin pathway involves the enzymatic cleavage of sphingomyelin to produce ceramide, a second messenger that serves as a key mediator in the rapid apoptotic response to various cell stressors. Low-linear energy transfer (LET) γ radiation can initiate this pathway, independent of DNA damage, via the cell membrane. Whether short-ranged, high-LET a particles, which are of interest as potent environmental carcinogens, radiotherapies and potential components of dirty bombs, can act thro...

  8. Depolarized light scattering from prolate anisotropic particles: The influence of the particle shape on the field autocorrelation function.

    Science.gov (United States)

    Passow, Christopher; ten Hagen, Borge; Löwen, Hartmut; Wagner, Joachim

    2015-07-28

    We provide a theoretical analysis for the intermediate scattering function typically measured in depolarized dynamic light scattering experiments. We calculate the field autocorrelation function g1(VH)(Q,t) in dependence on the wave vector Q and the time t explicitly in a vertical-horizontal scattering geometry for differently shaped solids of revolution. The shape of prolate cylinders, spherocylinders, spindles, and double cones with variable aspect ratio is expanded in rotational invariants flm(r). By Fourier transform of these expansion coefficients, a formal multipole expansion of the scattering function is obtained, which is used to calculate the weighting coefficients appearing in the depolarized scattering function. In addition to translational and rotational diffusion, especially the translational-rotational coupling of shape-anisotropic objects is considered. From the short-time behavior of the intermediate scattering function, the first cumulants Γ(Q) are calculated. In a depolarized scattering experiment, they deviate from the simple proportionality to Q(2). The coefficients flm(Q) strongly depend on the geometry and aspect ratio of the particles. The time dependence, in addition, is governed by the translational and rotational diffusion tensors, which are calculated by means of bead models for differently shaped particles in dependence on their aspect ratio. Therefore, our analysis shows how details of the particle shape--beyond their aspect ratio--can be determined by a precise scattering experiment. This is of high relevance in understanding smart materials which involve suspensions of anisotropic colloidal particles. PMID:26233160

  9. Influence of a high-speed dielectric spherical particle's movement on its scattering characteristics

    Institute of Scientific and Technical Information of China (English)

    Mingjun Wang; Zhensen Wu; Yingle Li

    2007-01-01

    The scattered field and differential scattered section (DSS) of a moving spherical particle with a high speed are investigated numerically. The coordinate and vector transformations are used to establish a theoretical basis for studying the laser scattering of a moving particle. The DSS of a moving spherical particle is explained by the electric and magnetic field from Mie scattering theory. Assuming the laser wavelength of 1.06 μm, we compute the ratio of the laser DSS of the moving dielectric spherical particle to that of the static dielectric spherical particle, which changes with radii, speeds and scattering angles of the particle. The numerical results show that the laser DSS of the oving pherical particle is tightly connected with its speed and scattering zenith angle. If a spherical particle moves with high speed, the laser DSS due to movement of the particle could not be neglected. If the speed of the dielectric spherical particle is fluctuating, the Doppler effect and the frequency spectrum expansion play important roles.

  10. Scanning of irradiated silicon detectors using $\\alpha$ particles and low energy protons

    CERN Document Server

    Casse, G L; Glaser, M; Kohout, Z; Konícek, J; Lemeilleur, F; Leroy, C; Linhart, V; Mares, J J; Pospísil, S; Roy, P; Sopko, B; Sinor, M; Svejda, J; Vorobel, V; Wilhelm, I

    1999-01-01

    In a spectroscopic study of non-irradiated and proton-irradiated silicon diodes, the detectors were illuminated from the front side and from the rear side by various alpha particle sources (mainly ThC') and by monoenergetic protons with energies from 1.0 to 2.5~MeV. Their response characteristics have been studied as a function of the incoming particle energy and the applied bias voltage. The charge collection efficiency was determined as a function of fluence

  11. Implementation of background scattering variance reduction on the RapidNano particle scanner

    OpenAIRE

    van der Walle, P.; Hannemann, S.; Eijk, D.(Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands); Mulckhuyse, W.F.W.; Donck, J.C.J. van der

    2014-01-01

    The background in simple dark field particle inspection shows a high scatter variance which cannot be distinguished from signals by small particles. According to our models, illumination from different azimuths can reduce the background variance. A multi-azimuth illumination has been successfully integrated on the Rapid Nano particle scanner. This illumination method reduces the variance of the background scattering on substrate roughness. It allows for a lower setting of the detection thresh...

  12. Alpha-particle emission from contaminants in counter materials

    International Nuclear Information System (INIS)

    Energy spectra of surface activities from thorium and uranium contaminants have been investigated for typical counter materials. Soft-tempered stainless steel with a rate of 1.2±0.1 α-particles emitted per 100 cm2 in one hour was found better than other stainless steel and far better than brass and aluminum. Energy spectra provide information about the contaminating activity and about its depth profile. Thorium, uranium and 210Pb contamination was also observed for thin sources of other materials including isotopically enriched materials. (orig.)

  13. Preequilibrium decay in alpha particle induced reactions in terbium

    International Nuclear Information System (INIS)

    The excitation functions of 159 Tb(α,n), (α,3 n), (α,4 n), (α,α3 n) reactions were measured using stacked foil activation technique and HPGe gamma ray spectroscopy method up to 50 MeV. The experimental results were compared with the theoretical predictions considering equilibrium as well as preequilibrium contributions using code ALICE/90. It was found that the initial exciton configuration n0 = 4(4p0h) that is pure particle state, appears to give good fit to the experimental data. (Authors)

  14. Benchmark and combined velocity-space tomography of fast-ion D-alpha spectroscopy and collective Thomson scattering measurements

    DEFF Research Database (Denmark)

    Jacobsen, Asger Schou; Salewski, Mirko; Geiger, B.;

    2016-01-01

    We demonstrate the combination of fast-ion D-alpha spectroscopy (FIDA) and collective Thomson scattering (CTS) measurements to determine a common best estimate of the fastion velocity distribution function by velocity-space tomography. We further demonstrate a benchmark of FIDA tomography and CTS...

  15. Simulations of alpha particle ripple loss from the International Thermonuclear Experimental Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Redi, M.H.; Budny, R.V.; McCune, D.C.; Miller, C.O.; White, R.B.

    1996-05-01

    Calculations of collisional stochastic ripple loss of alpha particles from the new 20 toroidal field (TF) coil International Thermonuclear Experimental Reactor (ITER) predict small alpha ripple losses, less than 0.4%, close to the loss calculated for the full current operation of the earlier 24 TF coil design. An analytic fit is obtained to the ITER ripple data field demonstrating the nonlinear height dependence of the ripple minimum for D shaped ripple contours. In contrast to alpha loss simulations for the Tokamak Fusion Test Reactor (TFTR), a simple Goldston, White, Boozer stochastic loss criterion ripple loss model is found to require an increased renormalization of the stochastic threshold {delta}{sub s}/{delta}{sub GWB} {ge} 1. Effects of collisions, sawtooth broadening and reversal of the grad B drift direction are included in the particle following simulations.

  16. Simulations of alpha particle ripple loss from the International Thermonuclear Experimental Reactor

    International Nuclear Information System (INIS)

    Calculations of collisional stochastic ripple loss of alpha particles from the new 20 toroidal field (TF) coil International Thermonuclear Experimental Reactor (ITER) predict small alpha ripple losses, less than 0.4%, close to the loss calculated for the full current operation of the earlier 24 TF coil design. An analytic fit is obtained to the ITER ripple data field demonstrating the nonlinear height dependence of the ripple minimum for D shaped ripple contours. In contrast to alpha loss simulations for the Tokamak Fusion Test Reactor (TFTR), a simple Goldston, White, Boozer stochastic loss criterion ripple loss model is found to require an increased renormalization of the stochastic threshold δs/δGWB ≥ 1. Effects of collisions, sawtooth broadening and reversal of the grad B drift direction are included in the particle following simulations

  17. Production of $\\alpha$-particle condensate states in heavy-ion collisions

    CERN Document Server

    Raduta, Ad R; Geraci, E; Neindre, N Le; Napolitani, P; Rivet, M F; Alba, R; Amorini, F; Cardella, G; Chatterjee, M; De Filippo, E; Guinet, D; Lautesse, P; La Guidara, E; Lanzalone, G; Lanzano, G; Lombardo, I; Lopez, O; Maiolino, C; Pagano, A; Pirrone, S; Politi, G; Porto, F; Rizzo, F; Russotto, P; Wieleczko, J P

    2010-01-01

    The fragmentation of quasi-projectiles from the nuclear reaction $^{40}Ca$ + $^{12}C$ at 25 MeV/nucleon was used to produce excited states candidates to $\\alpha$-particle condensation. The experiment was performed at LNS-Catania using the CHIMERA multidetector. Accepting the emission simultaneity and equality among the $\\alpha$-particle kinetic energies as experimental criteria for deciding in favor of the condensate nature of an excited state, we analyze the $0_2^+$ and $2_2^+$ states of $^{12}$C and the $0_6^+$ state of $^{16}$O. A sub-class of events corresponding to the direct 3-$\\alpha$ decay of the Hoyle state is isolated.

  18. Collisionless Evolution of Isotropic Alpha-Particle Distribution in a Tokamak

    International Nuclear Information System (INIS)

    Full text: The density of the noninductive current generated due to collisionless motion of alpha-particles in the tokamak magnetic field is calculated. The analysis is based on fully three-dimensional calculations of charged particle trajectories without simplifying assumptions typical for drift and neoclassical approaches. The current is calculated over the entire cross section of the plasma column, including the magnetic axis. It is shown that the current density is not a function of a magnetic surface and is strongly polarized over the poloidal angle. The current density distribution in the tokamak poloidal cross section is obtained, and the current density as a function of the safety factor profile, the tokamak aspect ratio, and the ratio of the particle Larmor radius on the axis to the tokamak minor radius is determined. It is shown that, when the source of alpha-particles is spatially nonuniform, the current density in the center of the tokamak is nonzero due to asymmetry of the phase-space boundary between trapped and passing particles. The current density scaling in the tokamak center differs from the known approximations for the bootstrap current and is sensitive to the spatial distribution of alpha-particles. (author)

  19. Light scattering by a spherical particle with multiple densely packed inclusions

    Institute of Scientific and Technical Information of China (English)

    Sun Xian-Ming; Wang Hai-Hua; Liu Wan-Qiang; Shen Ji

    2009-01-01

    This paper calculates light scattering by a spherical water particle containing densely packed inclusions at a visible wavelength 0.55 μm by a combination of ray-tracing and Monte Carlo techniques. While the individual reflection and refraction events at the outer boundary of a sphere particle are considered by a ray-tracing program, the Monte Carlo routine simulates internal scattering processes. The main advantage of this method is that the shape of the particle can be arbitrary, and multiple scattering can be considered in the internal scattering processes. A dense-medium light-scattering theory based on the introduction of the static structure factor is used to calculate the phase function and asymmetry parameters for densely packed inclusions. Numerical results of the single scattering characteristics for a sphere containing multiple densely packed inclusions are given.

  20. Radar scattering by planetary surfaces modeled with laboratory-characterized particles

    Science.gov (United States)

    Virkki, A.; Muinonen, K.

    2016-05-01

    We model radar scattering by planetary surfaces using a ray-optics algorithm that includes Fresnelian reflection and refraction, diffuse scattering, and coherent backscattering. We enhance the realism of the ray-optics algorithm by using scattering particles that are geometrically representative of the surfaces and interiors of planetary bodies. The shapes as well as the dielectric properties of the scattering particles have been characterized in laboratory. The results demonstrate the effects of various physical parameters on radar scattering with an emphasis on asteroids. We present the effects of number density, size distribution, and dielectric and geometric properties of scattering particles on the radar reflectivity and circular-polarization ratio of planetary surfaces. We also briefly discuss applications to the Galilean Moon Europa and comets.

  1. A variational calculation of 12C in the alpha-particle model

    International Nuclear Information System (INIS)

    Some physical properties of three structureless alpha particles interacting through two-body potentials were discussed. Comparison between them and the corresponding experimental observations for the 12C nucleus is done. The wave function is expanded in terms of translationally invariant harmonic-oscillator states, the coefficients being variational parameters

  2. Interaction of alpha particles at the cellular level - Implications for the radiation weighting factor

    International Nuclear Information System (INIS)

    Since low dose effects of alpha particles are produced by cellular hits in a relatively small fraction of exposed cells, the present study focuses on alpha particle interactions in bronchial epithelial cells following exposure to inhaled radon progeny. A computer code was developed for the calculation of microdosimetric spectra, dose and hit probabilities for alpha particles emitted from uniform and non-uniform source distributions in cylindrical and Y-shaped bronchial airway geometries. Activity accumulations at the dividing spur of bronchial airway bifurcations produce hot spots of cellular hits, indicating that a small fraction of cells located at such sites may receive substantially higher doses. While presently available data on in vitro transformation frequencies suggest that the relative biological effectiveness for alpha particles ranges from about 3 to 10, the effect of inhomogeneous activity distributions of radon progeny may slightly increase the radiation weighting factor relative to a uniform distribution. Thus a radiation weighting factor of about 10 may be more realistic than the current value of 20, at least for lung cancer risk following inhalation of short-lived radon progeny. (authors)

  3. alpha-particle radioactivity from LR 115 by two methods of analysis

    CERN Document Server

    Azkour, K; Adloff, J C; Pape, A

    1999-01-01

    LR115 track detectors were exposed to samples of Moroccan phosphate and phosphogypsum to measure their alpha-particle radioactivity. Then two formalisms were used for the dosimetry: simulation by a Monte Carlo method and determination of concentrations from a numerically integrated track registration equation. The results were compared with those deduced gamma-ray spectrometry.

  4. Alpha and beta particle induced scintillations in liquid and solid neon

    CERN Document Server

    Michniak, R A; McKinsey, D N; Doyle, J M

    2002-01-01

    Scintillations induced by alpha and beta particles in liquid and solid neon are studied and their light yield measured. Charged particle scintillation in neon is primarily in the extreme ultraviolet (EUV). We detect this EUV light by converting it to blue using a wavelength shifting fluor and detecting the blue light with a photomultiplier tube. It is observed that liquid neon is a somewhat less-efficient scintillator than liquid helium for both alpha and beta radiation while the light yield in solid neon is greater than in liquid helium. Based on our measurements of the relative light yields of liquid and solid neon to liquid helium whose absolute light yield has previously been determined, we find that an alpha source in liquid neon produces up to 5900 photons per MeV while a beta source produces up to 7400 photons per MeV. In solid neon, we find that an alpha particle produces up to 9300 photons per MeV while a beta particle produces up to 17,000 photons per MeV. We observe a significant dependence of the ...

  5. Alpha particle effects as a test domain for PAP, a Plasma Apprentice Program

    International Nuclear Information System (INIS)

    A new type of computational tool under development, employing techniques of symbolic computation and artificial intelligence to automate as far as possible the research activities of a human plasma theorist, is described. Its present and potential uses are illustrated using the area of the theory of alpha particle effects in fusion plasmas as a sample domain. (orig.)

  6. RADON AND PROGENY ALPHA-PARTICLE ENERGY ANALYSIS USING NUCLEAR TRACK METHODOLOGY

    International Nuclear Information System (INIS)

    A preliminary procedure for alpha energy analysis of radon and progeny using Nuclear Track Methodology (NTM) is described in this paper. The method is based on the relationship between alpha-particle energies deposited in polycarbonate material (CR-39) and the track size developed after a well-established chemical etching process. Track geometry, defined by parameters such as major or minor diameters, track area and overall track length, is shown to correlate with alpha-particle energy over the range 6.00 MeV (218Po) to 7.69 MeV (214Po). Track features are measured and the data analyzed automatically using a digital imaging system and commercial PC software. Examination of particle track diameters in CR-39 exposed to environmental radon reveals a multi-modal distribution. Locations of the maxima in this distribution are highly correlated with alpha particle energies of radon daughters, and the distributions are sufficiently resolved to identify the radioisotopes. This method can be useful for estimating the radiation dose from indoor exposure to radon and its progeny.

  7. Cross section balance in the 14N+159Tb reaction and the origin of fast alpha particles

    International Nuclear Information System (INIS)

    Exclusive cross sections have been obtained from particle-K X-ray coincidence data measured at 236 MeV for ejectiles ranging from 4He to 15N. Production cross sections for primary fragments and alpha particle multiplicities associated with different channels have been deduced. The major fraction of the alpha particles appears to originate from inelastic (damped) processes in which only light particles with Z<=2 are emitted. (orig.)

  8. Some characteristics of the CR-39 solid state nuclear - Track Detector for register of protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Experimental results related to registration properties of the CR-39 Solid State Nuclear Track Detector for charged particles are presented and discussed. The existence of an inverse proportion between the induction time and the temperature as well as normal concentration of solutions, is showed by the study of CR-39 chemical etching characteristics in NaOH and KOH solutions, comprising varied concentration and temperature. The bulk-etch rate and activation energy of the process were obtained. The critical energy and critical energy-loss rate of CR-39 track-detectors for registration of protons were experimentally determined. Samples were exposed to 24 Mev proton beams in the IEN/CNEN Cyclotron (CV-28), using scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples, in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy the critical energy was obtained. From the calculated energy-loss rate vs. energy curve, the critical energy loss rate were evaluated. The CR-39 response for low energy alpha particles (E = 7h) under the conditions of 6.25 N NaOH at 700C. It is shown that successive chemical etchings do not produce the same track geometry as obtained by means of a continous revelation with the same total etching time. (Author)

  9. Investigations of electrical properties of structures Al-DNA-ITO-Al exposed to alpha particles

    International Nuclear Information System (INIS)

    The detection of alpha particles and other radiation sources has been an important field of research since the inception of radioactive materials in medical technology approximately a century ago. While different types of radiation sensors exist, in recent history, in light of a few catastrophic nuclear meltdowns, the development of sensors with rapid and effective detection properties have become crucial. To probe the feasibility of incorporating such features into the detector architecture, a simple sensor based on mushroom Deoxyribonucleic acid or DNA (Aluminium (Al)/DNA/Indium Tin Oxide (ITO)) was built, and the possibility of employing DNA electronics for the potential detection of alpha particles was investigated. Current–voltage (I–V) profiles were obtained following radiation using alpha particles at different dosages and exposure periods at room temperature. Properties such as series resistance, RS and other properties (barrier height, ideality factor and hypersensitivity) were calculated and analyzed using Conventional, Cheung and Cheung and Norde methods. RS values of the non-radiated samples calculated using the first method was about 8.6 MΩ. Using Conventional and Norde methods, samples irradiated for 4 min demonstrated the highest RS values of 5.79 and 1.81 MΩ, respectively. The results obtained were used to demonstrate the possibility of applying the sensitivity of DNA sensors to the measurement of alpha radiation. - Highlights: • Freshly prepared DNA solution was deposited as thin films by using the self-assembly method. • Series resistances, barrier heights and ideality factors were determined from I–V measurements. • A novel DNA hypersensitivity phenomenon was observed at low alpha radiation. • DNA based diodes can be employed as sensitive alpha particle sensors

  10. Lung cancer risk from exposure to alpha particles and inhalation of other pollutants in rats

    Energy Technology Data Exchange (ETDEWEB)

    Burns, F.J.

    1990-01-01

    The goal of these experiments is to establish a quantitative correlation between early DNA damage and cancer incidence in a way that would be helpful for assessing the carcinogenic risk of radon alone or in combination with specific indoor pollutants. Rat tracheal epithelium has been exposed in vivo to {sup 210}Po alpha particles in the presence and absence of NO{sub 2} or cigarette smoke. The major accomplishments so far are: the design and implementation of a tracheal implant to simulate radon alpha particle exposure, the measurement of DNA breaks in a small 7.0 mm segment of the trachea exposed to external x-irradiation, the measurement of the rate of repair of the x-ray induced tracheal DNA strand breaks, the measurement of DNA strand breaks following inhalation of cigarette smoke or NO{sub 2}, the measurement of tracheal DNA stand breaks following exposure to high doses {sup 210}Po alpha particle radiation, the assessment of the amount of mucous in the goblet cells and in the underlying mucous glands. So far we have been unable to detect DNA strand breaks in the tracheal epithelium as a result of exposure to NO{sub 2} cigarette smoke or {sup 210}Po alpha particles. We have developed a simple artificial' trachea consisting of rat tracheal epithelial cells growing on a basement membrane coated millipore filter. Experiments are proposed to utilize these artificial tracheas to eliminate the potential interference of increased mucous secretion and/or inflammation that can significantly affect the radiation dose from the alpha particles. 61 refs., 17 figs.

  11. Scattering of particles with inclusions. Modeling and inverse problem solution in the Rayleigh-Gans approximation

    International Nuclear Information System (INIS)

    An analytic model for the scattering of a spherical particle with spherical inclusions has been proposed under the RG approximation. The model can be used without limitations to describe an X-ray scattering experiment. However, for light scattering several conditions must be fulfilled. Based on this model an inverse methodology is proposed to estimate the radii of host particle and inclusions, the number of inclusions and the Distance Distribution Functions (DDF's) of the distances between inclusions and the distances between inclusions and the origin of coordinates. The methodology is numerically tested in a light scattering example in which the host particle is eliminated by matching the refractive indices of host particle and medium. The results obtained for this cluster particle are very satisfactory.

  12. Sensitivity of alpha-decay to the real alpha-nucleus potential

    International Nuclear Information System (INIS)

    The information which can be obtained from studies of low energy alpha-particle scattering from heavy nuclei and from alpha-decay is discussed. The sensitivity of calculated widths and lifetimes for alpha-decay to the real nuclear potential is examined in detail using a formalism based on the unified theory of nuclear reactions. It is shown that a combined study of alpha-decay and alpha-particle scattering at energies near the Coulomb barrier should give a very precise determination of the barrier height and radius, although there is a more uniquely defined separation distance some way beyond the barrier. (orig.)

  13. Alfvenic behavior of alpha particle driven ion cyclotron emission in TFTR

    International Nuclear Information System (INIS)

    Ion cyclotron emission (ICE) has been observed during D-T discharges in the Tokamak Fusion Test Reactor (TFTR), using rf probes located near the top and bottom of the vacuum vessel. Harmonics of the alpha cyclotron frequency (Ωα) evaluated at the outer midplane plasma edge are observed at the onset of the beam injection phase of TFTR supershots, and persist for approximately 100-250 ms. These results are in contrast with observations of ICE in JET, in which harmonics of Ωα evolve with the alpha population in the plasma edge. Such differences are believed to be due to the fact that newly-born fusion alpha particles are super-Alfvenic near the edge of JET plasmas, while they are sub-Alfvenic near the edge of TFTR supershot plasmas. In TFTR discharges with edge densities such that newly-born alpha particles are super-Alfvenic, alpha cyclotron harmonics are observed to persist. These results are in qualitative agreement with numerical calculations of growth rates due to the magnetoacoustic cyclotron instability

  14. A survey of the alpha-nucleon interaction

    International Nuclear Information System (INIS)

    A survey of the alpha-nucleon interaction is made. The experimental work on angular distributions of differential scattering cross-sections and polarizations in proton-alpha and neutron-alpha scattering is described. The phenomenological approach which includes the study of both local and non-local potentials reproducing the experimental alpha-nucleon scattering data, is discussed. Basic studies of the alpha-nucleon interaction attempting to build an interaction between an alpha particle and a nucleon from first principles are then described. A critical discussion of the results with some concluding remarks suggesting the direction for further investigation is made. (author)

  15. Fokker Planck kinetic modeling of suprathermal alpha-particles in a fusion plasma

    CERN Document Server

    Peigney, Benjamin-Edouard; Tikhonchuk, Vladimir

    2014-01-01

    We present an ion kinetic model describing the ignition and burn of the deuterium-tritium fuel of inertial fusion targets. The analysis of the underlying physical model enables us to develop efficient numerical methods to simulate the creation, transport and collisional relaxation of fusion reaction products (alpha-particles) at a kinetic level. A two-energy-scale approach leads to a self-consistent modeling of the coupling between suprathermal alpha-particles and the thermal bulk of the imploding plasma. This method provides an accurate numerical treatment of energy deposition and transport processes involving suprathermal particles. The numerical tools presented here are validated against known analytical results. This enables us to investigate the potential role of ion kinetic effects on the physics of ignition and thermonuclear burn in inertial confinement fusion schemes.

  16. A Further Measurement of the beta-Delayed alpha-Particle Emission of 16N

    CERN Document Server

    III, R H F; McDonald, J E; Wilds, E L

    2007-01-01

    We measured the beta-delayed alpha-particle emission spectrum of 16N with a sensitivity for beta-decay branching ratios of the order of 10-10. The 16N nuclei were produced using the d(15N,16N)p reaction with 70 MeV 15N beams and a deuterium gas target 7.5 cm long at a pressure of 1250 torr. The 16N nuclei were collected (over 10 s) using a thin aluminum foil with an areal density of 180 mu g/cm2 tilted at 7 Deg with respect to the beam. The activity was transferred to the counting area by means of a stepping motor in less than 3 s with the counting carried out over 8 s. The beta-delayed alpha-particles were measured using a time of flight method to achieve a sufficiently low background. Standard calibration sources (148Gd, 241Am, 208,209Po, and 227Ac) as well as alpha-particles and 7Li from the 10B(n,alpha)7Li reaction were used for an accurate energy calibration. The energy resolution of the catcher foil (180-220 keV) was calculated and the time of flight resolution (3-10 nsec) was measured using the beta-de...

  17. Electronic Properties of DNA-Based Schottky Barrier Diodes in Response to Alpha Particles

    Directory of Open Access Journals (Sweden)

    Hassan Maktuff Jaber Al-Ta'ii

    2015-05-01

    Full Text Available Detection of nuclear radiation such as alpha particles has become an important field of research in recent history due to nuclear threats and accidents. In this context; deoxyribonucleic acid (DNA acting as an organic semiconducting material could be utilized in a metal/semiconductor Schottky junction for detecting alpha particles. In this work we demonstrate for the first time the effect of alpha irradiation on an Al/DNA/p-Si/Al Schottky diode by investigating its current-voltage characteristics. The diodes were exposed for different periods (0–20 min of irradiation. Various diode parameters such as ideality factor, barrier height, series resistance, Richardson constant and saturation current were then determined using conventional, Cheung and Cheung’s and Norde methods. Generally, ideality factor or n values were observed to be greater than unity, which indicates the influence of some other current transport mechanism besides thermionic processes. Results indicated ideality factor variation between 9.97 and 9.57 for irradiation times between the ranges 0 to 20 min. Increase in the series resistance with increase in irradiation time was also observed when calculated using conventional and Cheung and Cheung’s methods. These responses demonstrate that changes in the electrical characteristics of the metal-semiconductor-metal diode could be further utilized as sensing elements to detect alpha particles.

  18. Track Reconstruction and Performance of DRIFT Directional Dark Matter Detectors using Alpha Particles

    CERN Document Server

    Burgos, S; Ghag, C; Gold, M; Kudryavtsev, V A; Lawson, T B; Loomba, D; Majewski, P; McMillan, J E; Muna, D; Murphy, A StJ; Nicklin, G G; Paling, S M; Petkov, A; Plank, S J S; Robinson, M; Sanghi, N; Smith, N J T; Snowden-Ifft, D P; Spooner, N J C; Sumner, T J; Turk, J; Tziaferi, T

    2007-01-01

    First results are presented from an analysis of data from the DRIFT-IIa and DRIFT-IIb directional dark matter detectors at Boulby Mine in which alpha particle tracks were reconstructed and used to characterise detector performance--an important step towards optimising directional technology. The drift velocity in DRIFT-IIa was [59.3 +/- 0.2 (stat) +/- 7.5 (sys)] m/s based on an analysis of naturally-occurring alpha-emitting background. The drift velocity in DRIFT-IIb was [57 +/- 1 (stat) +/- 3 (sys)] m/s determined by the analysis of alpha particle tracks from a Po-210 source. 3D range reconstruction and energy spectra were used to identify alpha particles from the decay of Rn-222, Po-218, Rn-220 and Po-216. This study found that (22 +/- 2)% of Po-218 progeny (from Rn-222 decay) are produced with no net charge in 40 Torr CS2. For Po-216 progeny (from Rn-220 decay) the uncharged fraction is (100 +0 -35)%.

  19. Registration of alpha particles in Makrofol-E nuclear track detectors

    Science.gov (United States)

    Rammah, Y. S.; Abdalla, Ayman M.; Ashraf, O.; Ashry, A. H.

    2016-06-01

    Fast detection of alpha particles in the range from 1 to 5 MeV in Makrofol-E polycarbonate nuclear track detectors (PCTDs) using a new chemical etchant was investigated. 252Cf and 241Am-thin open sources were used for irradiating Makrofol-E detectors with fission fragments and alpha particles in air at normal pressure and temperature (NPT). A chain of experimental work has been carried out using new etchants to register alpha particle in short time in Makrofol-E polycarbonate detectors. The etching efficiency were exhibited a clear dependence on the amount of methanol in the etching solution and etching time. The optimized chemical condition obtained at this stage of development for 200 μm Makrofol-E detectors are (8 ml of 10 N NaOH + 2 ml CH3OH) etching solutions at 60 °C for 3 h. In this study; it is possible to observe energy detection windows for Makrofol-E detectors according to applied etching duration. Makrofol-E introduced the characteristic Bragg peak, which indicates the advantages of this detector as alpha spectrometer. Consequently, the suggested new etchant can be developed for heavy ions detection and monitoring radon levels and its daughters.

  20. Measuring shape and size of micrometric particles from the analysis of the forward scattered field

    Science.gov (United States)

    Villa, S.; Sanvito, T.; Paroli, B.; Pullia, A.; Delmonte, B.; Potenza, M. A. C.

    2016-06-01

    Characterizing nano- and micro-particles in fluids still proves to be a significant challenge for both science and industry. Here, we show how to determine shape and size distributions of polydisperse water suspensions of micron-sized particles by the analysis of the field scattered in the forward direction by single particles illuminated by a laser beam. We exploit the novel Single Particle Extinction and Scattering method in connection with shear conditions which give preferred orientations to the particles passing through the scattering volume. Water suspensions of calibrated non-spherical particles, polydisperse standard monophasic mineral samples of quartz and kaolinite, and a mixture of quartz and illite are studied in detail. Application and limitation of the method are discussed.

  1. Skeletal dosimetry models for alpha-particles for use in molecular radiotherapy

    Science.gov (United States)

    Watchman, Christopher J.

    Molecular radiotherapy is a cancer treatment methodology whereby a radionuclide is combined with a biologically active molecule to preferentially target cancer cells. Alpha-particle emitting radionuclides show significant potential for use in molecular radiotherapy due to the short range of the alpha-particles in tissue and their high rates of energy deposition. Current radiation dosimetry models used to assess alpha emitter dose in the skeleton were developed originally for occupational applications. In medical dosimetry, individual variability in uptake, translocation and other biological factors can result in poor correlation of clinical outcome with marrow dose estimates determined using existing skeletal models. Methods presented in this work were developed in response to the need for dosimetry models which account for these biological and patient-specific factors. Dosimetry models are presented for trabecular bone alpha particle dosimetry as well as a model for cortical bone dosimetry. These radiation transport models are the 3D chord-based infinite spongiosa transport model (3D-CBIST) and the chord-based infinite cortical transport model (CBICT), respectively. Absorbed fraction data for several skeletal tissues for several subjects are presented. Each modeling strategy accounts for biological parameters, such as bone marrow cellularity, not previously incorporated into alpha-particle skeletal dosimetry models used in radiation protection. Using these data a study investigating the variability in alpha-particle absorbed fractions in the human skeleton is also presented. Data is also offered relating skeletal tissue masses in individual bone sites for a range of ages. These data are necessary for dose calculations and have previously only been available as whole body tissue masses. A revised 3D-CBIST model is also presented which allows for changes in endosteum thickness to account for revised target cell location of tissues involved in the radiological

  2. Particle and nuclear scattering at large momentum transfers

    International Nuclear Information System (INIS)

    The author gives an introduction to the the elementary particle aspects of nuclear reactions. Especially he discusses elementary particle interactions occurring in nuclear reactions. Furthermore some experimental results are presented. (orig./HSI)

  3. Alpha particle induced DNA damage and repair in normal cultured thyrocytes of different proliferation status

    Energy Technology Data Exchange (ETDEWEB)

    Lyckesvärd, Madeleine Nordén, E-mail: madeleine.lyckesvard@oncology.gu.se [Department of Oncology, Sahlgrenska Academy, University of Gothenburg (Sweden); Delle, Ulla; Kahu, Helena [Department of Oncology, Sahlgrenska Academy, University of Gothenburg (Sweden); Lindegren, Sture [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg (Sweden); Jensen, Holger [The PET and Cyclotron Unit Copenhagen University Hospital, Rigshospitalet (Denmark); Bäck, Tom [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg (Sweden); Swanpalmer, John [Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg (Sweden); Elmroth, Kecke [Department of Oncology, Sahlgrenska Academy, University of Gothenburg (Sweden)

    2014-07-15

    Highlights: • We study DNA damage response to low-LET photons and high-LET alpha particles. • Cycling primary thyrocytes are more sensitive to radiation than stationary cells. • Influence of radiation quality varies due to cell cycle status of normal cells. • High-LET radiation gives rise to a sustained DNA damage response. - Abstract: Childhood exposure to ionizing radiation increases the risk of developing thyroid cancer later in life and this is suggested to be due to higher proliferation of the young thyroid. The interest of using high-LET alpha particles from Astatine-211 ({sup 211}At), concentrated in the thyroid by the same mechanism as {sup 131}I [1], in cancer treatment has increased during recent years because of its high efficiency in inducing biological damage and beneficial dose distribution when compared to low-LET radiation. Most knowledge of the DNA damage response in thyroid is from studies using low-LET irradiation and much less is known of high-LET irradiation. In this paper we investigated the DNA damage response and biological consequences to photons from Cobolt-60 ({sup 60}Co) and alpha particles from {sup 211}At in normal primary thyrocytes of different cell cycle status. For both radiation qualities the intensity levels of γH2AX decreased during the first 24 h in both cycling and stationary cultures and complete repair was seen in all cultures but cycling cells exposed to {sup 211}At. Compared to stationary cells alpha particles were more harmful for cycling cultures, an effect also seen at the pChk2 levels. Increasing ratios of micronuclei per cell nuclei were seen up to 1 Gy {sup 211}At. We found that primary thyrocytes were much more sensitive to alpha particle exposure compared with low-LET photons. Calculations of the relative biological effectiveness yielded higher RBE for cycling cells compared with stationary cultures at a modest level of damage, clearly demonstrating that cell cycle status influences the relative

  4. Electromagnetic scattering of high-permittivity particles on a substrate

    OpenAIRE

    Martin, O. J. F.; Gay-Balmaz, P.

    2001-01-01

    We contribute to the study of the optical properties of high-permittivity nanostructures deposited on surfaces. We present what we believe is anew computational technique derived from the coupled-dipole approximation (CDA), which can accommodate high-permittivity scatterers. The discretized CDA equations are reformulated by use of the sampling theory to overcome different sources of inaccuracy that arise for high-permittivity scatterers. We first give the nonretarded filtered surface Green's ...

  5. Scattering and absorption of particles by a black hole involving a global monopole

    Institute of Scientific and Technical Information of China (English)

    Shao Jian Zhou; Wang Yong Jiu

    2012-01-01

    Under the conditions that the wavelength of a particle is much larger than its radius of central mass,and the Schwarzschild field is weak,the scattering of a particle has been studied by many researchers.They obtained that scalar and vector particles abide by Rutherford's angle distribution by using the low level perturbation method and the scattered field's approximation in a weak field.The scattering cross section of a photon coincides with the section in Newton's field of point mass.We can obtain the photon's polarization effect by calculating the second-order perturbation in the linear Schwarzschild field.This article discusses the scattering and absorption of a particle by a black hole involving a global monopole by using the aforesaid method.

  6. Stimulated Brillouin scattering of an electromagnetic wave in weakly magnetized plasma with variably charged dust particles

    Indian Academy of Sciences (India)

    Sourabh Bal; M Bose

    2009-10-01

    We have investigated analytically the stimulated Brillouin scattering (SBS) of an electromagnetic wave in non-dissipative weakly magnetized plasma in the presence of dust particles with variable charge.

  7. Alfven Eigenmode And Ion Bernstein Wave Studies For Controlling Fusion Alpha Particles

    CERN Document Server

    Heeter, R F

    1999-01-01

    In magnetic confinement fusion reactor plasmas, the charged fusion products (such as alpha particles in deuterium-tritium plasmas) will be the dominant power source, and by controlling these charged fusion products using wave-particle interactions the reactor performance could be optimized. This thesis studies two candidate waves: Mode-Converted Ion Bernstein Waves (MCIBWs) and Alfvén Eigenmodes (AEs). Rates of MCIBW-driven losses of alpha-like fast deuterons, previously observed in the Tokamak Fusion Test Reactor (TFTR), are reproduced by a new model so that the wave-particle diffusion coefficient can be deduced. The MCIBW power in TFTR is found to be ∼ 1/3 that needed for collisionless alpha particle control. A reasonable reactor power scaling is derived. To study AEs, existing magnetic fluctuation probes at the Joint European Torus (JET) have been absolutely calibrated from 30–500 kHz for the first time, allowing fluctuation measurements with &vbm0;dBpol&vbm0;/B0&am...

  8. Photoluminescence detection of alpha particle using DAM-ADC nuclear detector

    Science.gov (United States)

    Abdalla, Ayman M.; Harraz, Farid A.; Ali, Atif M.; Al-Sayari, S. A.; Al-Hajry, A.

    2016-09-01

    The photoluminescence (PL) and UV-vis spectral analysis of DAM-ADC (diallyl maleate: DAM, polyallyl diglycol carbonate: ADC) nuclear detector are demonstrated for the first time. The DAM-ADC surfaces were exposed to thin 241Am disk source that emits alpha particles with activity 333 kBq. It is found that the track density of the irradiated samples remarkably influences the PL characteristics of the DAM-ADC detector. The spectral peak heights and the integrated intensities under the peaks exhibit linear correlations with correlation coefficient R2=0.9636 and 0.9806, respectively for different alpha particle fluences ranging from 8.16-40.82×107 particles/cm2. Additionally, a correlation coefficient R2=0.9734 was achieved for the UV-vis spectral analysis. The linear fitting functions, along with the corresponding fitting parameters were evaluated in each case. Both the PL and the UV-vis data of the irradiated DAM-ADC samples showed considerable spectral differences, and hence they would be used to offer sensitive approaches for alpha particle detection.

  9. Effect of Alpha-Particle Irradiation on Brain Glycogen in the Rat

    Science.gov (United States)

    Wolfe, L. S.; Klatzo, Igor; Miquel, Jaime; Tobias, Cornelius; Haymaker, Webb

    1962-01-01

    The studies of Klatzo, Miquel, Tobias and Haymaker (1961) have shown that one of the earliest and most sensitive indications of the effects of alpha-particle irradiation on rat bran is the appearance of glycogen granules mainly in the neuroglia of the exposed area of the brain. Periodic acid-Schiff (PAS) positive, alpha-amylase soluble granules were demonstrated within 12 hr after irradiation, preceding by approximately 36 hr the first microscopically detectable vascular permeability disturbances, as shown by the fluorescein labeled serum protein technique. These studies suggested that the injurious effects of alpha-particle energy were on cellular elements primarily, according to the physical properties and distribution of the radiation in the tissue, and that the vascular permeability disturbances played a secondary role in pathogenesis. The purpose of this study was to correlate the histochemical observations on glycogen with a quantitative assessment of the glycogen in the irradiated brain tissue. It is felt that such a study may contribute to the understanding of radiation injury at the molecular level. A practical aspect of this problem is that the information on biological radiation effects due to accelerated particles from the cyclotron source, is employed in this study, is applicable to radiation from cosmic particles both in free space and entrapped in the Van Allen belts.

  10. On the Theory and Simulation of Multiple Coulomb Scattering of Heavy Charged Particles

    OpenAIRE

    Striganov, S. I.

    2004-01-01

    The Moliere theory of multiple Coulomb scattering is modified to take into account difference between scattering off atomic nuclei and electron. A simple analytical expression for angular distribution of charged particles passing through a thick absorber is found. It does not assume any special form for a differential cross section and has wider range of applicability than a Gaussian approximation. A well-known method to simulate multiple Coulomb scattering is based on the different treatment...

  11. Factors affecting the energy resolution in alpha particle spectrometry with silicon diodes

    International Nuclear Information System (INIS)

    In this work are presented the studies about the response of a multi-structure guard rings silicon diode for detection and spectrometry of alpha particles. This ion-implanted diode (Al/p+/n/n+/Al) was processed out of 300 μm thick, n type substrate with a resistivity of 3 kΩ·cm and an active area of 4 mm2. In order to use this diode as a detector, the bias voltage was applied on the n+ side, the first guard ring was grounded and the electrical signals were readout from the p+ side. These signals were directly sent to a tailor made preamplifier, based on the hybrid circuit A250 (Amptek), followed by a conventional nuclear electronic. The results obtained with this system for the direct detection of alpha particles from 241Am showed an excellent response stability with a high detection efficiency (≅ 100 %). The performance of this diode for alpha particle spectrometry was studied and it was prioritized the influence of the polarization voltage, the electronic noise, the temperature and the source-diode distance on the energy resolution. The results showed that the major contribution for the deterioration of this parameter is due to the diode dead layer thickness (1 μm). However, even at room temperature, the energy resolution (FWHM = 18.8 keV) measured for the 5485.6 MeV alpha particles (241Am) is comparable to those obtained with ordinary silicon barrier detectors frequently used for these particles spectrometry. (author)

  12. MRST2001: partons and {alpha}{sub S} from precise deep inelastic scattering and Tevatron jet data

    Energy Technology Data Exchange (ETDEWEB)

    Martin, A.D.; Stirling, W.J. [Department of Physics and Institute for Particle Physics Phenomenology, University of Durham (United Kingdom); Roberts, R.G. [Theory Division, CERN, Geneva (Switzerland); Thorne, R.S. [Cavendish Laboratory, University of Cambridge (United Kingdom)

    2002-03-01

    We use all the available new precise data for deep inelastic and related hard scattering processes to perform NLO global parton analyses. These new data allow an improved determination of partons and, in particular, the inclusion of the recent measurements of the structure functions at HERA and of the inclusive jets at the Tevatron help to determine the gluon distribution and {alpha}{sub S} better than ever before. We find a somewhat smaller gluon at low x than previous determinations and that {alpha}{sub S}(M{sub Z}{sup 2})= 0.119{+-}0.002(expt.){+-}0.003 (theory). (orig.)

  13. Scattering of Gaussian beam by a spherical particle with a spheroidal inclusion

    International Nuclear Information System (INIS)

    A generalized Lorenz-Mie theory framework (GLMT) is applied to the study of Gaussian beam scattering by a spherical particle with an embedded spheroid at the center. By virtue of a transformation between the spherical and spheroidal vector wave functions, a theoretical procedure is developed to deal with the boundary conditions. Numerical results of the normalized differential scattering cross section are presented.

  14. Geometrical parameters of tracks registered by collimated alpha particles on CR-39 detector

    International Nuclear Information System (INIS)

    The latent tracks formed on CR-39 solid state track detector on exposure of alpha radiations emanating from a collimated 241Am source were developed by a chemical etching method. Alpha track images were captured by an optical microscope and were processed by using Image Pro-Plus (6.0) software. GEANT4 simulations were carried out to obtain the angular and energy distribution profiles of the alpha particles. Apart from fluence, geometric parameters like aspect ratio (the ratio of the major to minor axis) and the depth profiles of etched tracks were measured experimentally and correlated with simulated angular and energy profile of incident radiations. Reasonable agreement was observed in the fluence and depth profile information obtained from experiments and simulations

  15. The Aharonov–Bohm effect in scattering of short-wavelength particles

    International Nuclear Information System (INIS)

    Quantum-mechanical scattering of nonrelativistic charged particles by a magnetic vortex of nonzero transverse size is considered. We show that the flux of the vortex serves as a gate for the strictly forward propagation of particles with short, as compared to the transverse size of the vortex, wavelengths; this effect is the same for a penetrable vortex as for an impenetrable one. A possibility for the experimental detection of the scattering Aharonov–Bohm effect is discussed. (paper)

  16. Studying the dynamics of colloidal particles with digital holographic microscopy and electromagnetic scattering solutions

    Directory of Open Access Journals (Sweden)

    V. N. Manoharan

    2011-09-01

    Full Text Available Digital holographic microscopy (DHM can measure the 3D positions as well as the scattering properties of colloidal particles in a single 2D image. We describe DHM and our analysis of recorded holograms with exact scattering solutions, which permit the measurement of 3D particle positions with ∼10 nm precision and millisecond time resolution, and discuss studies of the Brownian dynamics of clusters of spheres with DHM.

  17. Generalized Faddeev Equations for N-Particle Scattering

    CERN Document Server

    Wei, G W

    2000-01-01

    A proposal is made for reducing the solution of the N-particle Lippmann-Schwinger equation to that of smaller sets of particles. This consists of first writing the N-particle equation in terms of all possible $N/2$-particle Lippmann-Schwinger equations. (If N is odd this needs a minor modification.) The second step requires a decoupling of the resolvents for the fewer particle systems so that each can be solved separately. This generalization of the Faddeev approach deals only with connected kernels and the homogeneous solution reproduces the N-particle Schr\\"odinger equation. For four particles the proposed method involves only a $3\\times3$ matrix whereas other approaches typically require the solution of at least a $7\\times7$ matrix equation.

  18. Simulation study for high resolution alpha particle spectrometry with mesh type collimator

    International Nuclear Information System (INIS)

    An alpha particle spectrometry with a mesh type collimator plays a crucial role in identifying specific radionuclide in a radioactive source collected from the atmosphere or environment. The energy resolution is degraded without collimation because particles with a high angle have a longer path to travel in the air. Therefore, collision with the background increases. The collimator can cut out particles which traveling at a high angle. As a result, an energy distribution with high resolution can be obtained. Therefore, the mesh type collimator is simulated for high resolution alpha particle spectrometry. In conclusion, the collimator can improve resolution. With collimator, the collimator is a role of cutting out particles with a high angle, so, low energy tail and broadened energy distribution can be reduced. The mesh diameter is found out as an important factor to control resolution and counting efficiency. Therefore, a target particle, for example, 235U, can be distinguished by a detector with a collimator under a mixture of various nuclides, for example: 232U, 238U, and 232Th

  19. Order $\\alpha_{s}^{2}$ Contributions to charm production in charged-current deep-inelastic lepton-hadron scattering

    CERN Document Server

    Buza, M

    1997-01-01

    The most important part of the order $\\alpha_s^2$ corrections to the charm component of the charged-current structure functions $F_2(x,Q^2)$ and $F_3(x,Q^2)$ have been calculated. This calculation is based on the asymptotic form of the heavy-quark coefficient functions corresponding to the higher order corrections to the W-boson-gluon fusion process. These coefficient functions which are in principle only valid for $Q^2 \\gg m^2$ can be also used to estimate the order $\\alpha_s^2$ contributions at lower $Q^2$ values provided $x < 0.1$. It turns out that the above corrections are appreciable in the large $Q^2$-region and they explain the discrepancy found for the structure functions between the fixed-flavour scheme (FFS) and the variable-flavour-number scheme (VFNS). These corrections also hamper the extraction of the strange-quark density from the data obtained for the charged-current and the electromagnetic-current processes.

  20. Tailored long range forces on polarizable particles by collective scattering of broadband radiation

    CERN Document Server

    Holzmann, Daniela

    2016-01-01

    Collective coherent light scattering by polarizable particles creates surprisingly strong, long range inter-particle forces originating from interference of the light scattered by different particles. While for monochromatic laser beams this interaction decays with the inverse distance, we show here that in general the effective interaction range and geometry can be controlled by the illumination bandwidth and geometry. As generic example we study the modifications inter-particle forces within a 1D chain of atoms trapped in the field of a confined optical nanofiber mode. For two particles we find short range attraction as well as optical binding at multiple distances. The range of stable distances shrinks with increasing light bandwidth and for a very large bandwidth field as e.g. blackbody radiation we find a strongly attractive potential up to a critical distance beyond which the force gets repulsive. Including multiple scattering can even lead to the appearance of a stable configuration at a large distance...

  1. Survival of human osteosarcoma cells and normal human fibroblasts following alpha particle irradiation

    International Nuclear Information System (INIS)

    Cell survival of human osteosarcoma cells in culture following alpha particle irradiation is reported here for the first time. The osteosarcoma cell line (TE-85) is found to be less sensitive to inactivation by 5.6 MeV alpha particles (LET 86 keV/μm) than normal diploid human fibroblasts (NFS). Values for the mean lethal doses were estimated to be 103 rads for the TE-85 cells compared with 68 rads for the NFS cultures irradiated under identical conditions. It is postulated that the aneuploidy of the tumor cells with increased DNA chromosomal material may confer a selective advantage for the survival of tumor cells relative to normal cells with diploid chromosomes

  2. Collisional stochastic ripple diffusion of alpha particles and beam ions on TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Redi, M.H.; Zarnstorff, M.C,; White, R.B.; Budny, R.V.; Schivell, J.F.; Scott, S.D.; Zweben, S.J.

    1994-09-01

    Predictions for ripple loss of fast ions from TFTR are investigated with a guiding center including both collisional and ripple effects. Discrepancies between measurements and calculations of plasma beta at low current and large major radius are resolved when both effects are included for neutral beam ions. A synergistic enhancement of fast ion diffusion is found for toroidal field ripple with collisions. S = 5.4 for neutral beam ions and S = 1.4--2.4 for alpha particles. A 20--30% reduction in alpha particle heating is predicted for R = 2.6 m DT plasmas on TFTR due to first orbit and collisional stochastic ripple diffusion, although these losses will be reduced if q{sub a} and R are smaller, as for most planned DT experiments.

  3. Collisional stochastic ripple diffusion of alpha particles and beam ions on TFTR

    International Nuclear Information System (INIS)

    Predictions for ripple loss of fast ions from TFTR are investigated with a guiding center including both collisional and ripple effects. Discrepancies between measurements and calculations of plasma beta at low current and large major radius are resolved when both effects are included for neutral beam ions. A synergistic enhancement of fast ion diffusion is found for toroidal field ripple with collisions. S = 5.4 for neutral beam ions and S = 1.4--2.4 for alpha particles. A 20--30% reduction in alpha particle heating is predicted for R = 2.6 m DT plasmas on TFTR due to first orbit and collisional stochastic ripple diffusion, although these losses will be reduced if qa and R are smaller, as for most planned DT experiments

  4. Turbulent transport of MeV range cyclotron heated minorities as compared to alpha particles

    CERN Document Server

    Pusztai, István; Kazakov, Yevgen O; Fülöp, Tünde

    2016-01-01

    We study the turbulent transport of an ion cyclotron resonance heated (ICRH), MeV range minority ion species in tokamak plasmas. Such highly energetic minorities, which can be produced in the three ion minority heating scheme [Ye. O. Kazakov et al. (2015) Nucl. Fusion 55, 032001], have been proposed to be used to experimentally study the confinement properties of fast ions without the generation of fusion alphas. We compare the turbulent transport properties of ICRH ions with that of fusion born alpha particles. Our results indicate that care must be taken when conclusions are drawn from experimental results: While the effect of turbulence on these particles is similar in terms of transport coefficients, differences in their distribution functions - ultimately their generation processes - make the resulting turbulent fluxes different.

  5. Biological dosimeter for UV-radiation and alpha particles, based on DNA damages

    International Nuclear Information System (INIS)

    A bioluminescence method for determination of biologically relevant (DNA damaging) doses of UV-radiation and alpha particles is developed. The method is based on bacterial luminescence as a bio-marker regulated by the SOS system. Cultures of E. coli cells transformed with the plasmid pPSL1 which carries the lux gene under control of the col promotor, an SOS-controlling gene, is used. The lux gene encode the enzyme luciferase which takes part in the reaction, resulting in the emission of a visible light at 490 nm. The light output is measured by photomultiplier and one channel analyzer. SOS-response kinetic curves of bacteria, UV-irradiated and treated with alpha particles, are obtained. An assessment of the risk from solar UV-radiation is made. The method has the sensitivity required to be used as biological UV-dosimeter (author)

  6. GAMCAT - a personal computer database on alpha particles and gamma rays from radioactive decay

    International Nuclear Information System (INIS)

    The GAMCAT database is a compilation of data describing the alpha particles and gamma rays that occur in the radioactive decay of all known nuclides, adapted for IBM Personal Computers and compatible systems. These compiled data have been previously published, and are now available as a compact database. Entries can be retrieved by defining the properties of the parent nuclei as well as alpha-particle and gamma-ray energies or any combination of these parameters. The system provides fast access to the data and has been completely written in C to run on an AT-compatible computer, with a hard disk and 640K of memory under DOS 2.11 or higher. GAMCAT is available from the Fachinformationszentrum Karlsruhe. (orig.)

  7. IAEA consultants' meeting on He-beam data base for alpha particle diagnostics of fusion plasmas

    International Nuclear Information System (INIS)

    The present Report contains the Summary of the IAEA Consultants' Meeting on ''He-Beam Data Base for Alpha Particle Diagnostics of Fusion Plasmas'' which was organized by the Atomic and Molecular Data Unit and held on June 3-5, 1991 at the IAEA Headquarters in Vienna, Austria. The Meeting Proceedings are briefly described and the reports of the Working Groups on the electron- and ion-impact processes are reproduced. A survey on the atomic data needs and required cross section accuracies for helium beam stopping calculations and alpha particle diagnostics of JET- and ITER-like plasmas is included. The conclusions and recommendations of the Meeting regarding the status of present data base (availability and quality) and the needs for its improvement are also given in this Summary Report. (author). Refs, figs and tabs

  8. Technique for measuring the losses of alpha particles to the wall in TFTR

    International Nuclear Information System (INIS)

    It is proposed to measure the losses of alpha particles to the wall in the Tokamak Fusion Test Reactor (TFTR) or any large deuterium-tritium (D-T) burning tokamak by a nuclear technique. For this purpose, a chamber containing a suitable fluid would be mounted near the wall of the tokamak. Alpha particles would enter the chamber through a thin window and cause nuclear reactions in the fluid. The material would then be transported through a tube to a remote, low-background location for measurement of the activity. The most favorable reaction suggested here is 10B(α,n)13N, although 14N(α,γ)18F and others may be possible. The system, the sensitivity, the probe design, and the sources of error are described

  9. Development of scintillator plates with high energy resolution for alpha particles made of GPS scintillator grains

    Science.gov (United States)

    Shimaoka, Takehiro; Kaneko, Junichi H.; Izaki, Kenji; Tsubota, Youichi; Higuchi, Mikio; Nishiyama, Shusuke

    2014-01-01

    A scintillator plate with high energy resolution was developed to produce an alpha particle monitor used in nuclear fuel reprocessing plants and mixed plutonium-uranium oxide (MOX) fuel plants. Grains of a Gd2Si2O7 (GPS) scintillator of several 10 to 550 μm were fixed on a glass substrate and were then mechanically polished. By increasing the size of scintillator grains and removing fine powders, the collected light yield and energy resolution for alpha particles were drastically improved. Energy resolution of 9.3% was achieved using average grain size of 91 μm. Furthermore, the ratios between counts in a peak and total counts were improved by more than 60% by the further increase of grain size and adoption of mechanically polished surfaces on both sides. Beta and gamma ray influences were suppressed sufficiently by the thin 100 μm scintillator plates.

  10. Conceptual design of confined alpha particle diagnostic system for ITER using an energetic He0 beam

    International Nuclear Information System (INIS)

    A conceptual design of an active-neutral-beam-probe-diagnostic-system for alpha particles produced by D-T nuclear reaction in a plasma confined by a magnetic fusion reactor has been examined. An energetic He0 beam plays an important role in the system. To detect a signal of neutralized alpha particles from the fusion plasma with enough S/N ratios, a high brightness He0 beam produced by spontaneous electron detachment from He- ions is required. A prototype of a He+ ion source has been designed and assembled to test the performance in producing a source beam for high intensity He- beam through a double-charge-exchange process in alkali metal vapor. (author)

  11. Rayleigh like scattering from silica–titania core-shell particles and their application in protection against harmful ultraviolet rays

    Indian Academy of Sciences (India)

    Sudipta G Dastidar; P Bharath; Arindam Roy

    2011-04-01

    In this article we report experimental and theoretical results of angle-dependent laser light scattering of nano titanium dioxide nucleated on silica particles. It was observed that the experimental scattering profile from nano-titania coated silica (TCS) particle resembles that of a Rayleigh scattering. It can be inferred from the light scattering profile that nucleating fine particles onto a surface of a bigger particle (core), the resulting scattering profile is dominated by the smaller particles. Thin film transmittance measurement of TCS particles also supports this claim. The theoretical scattering predictions do not match with the experimental findings and the reasons for the discrepancies are addressed. This Rayleigh-like scattering property of TCS particles can be used in cosmetic formulations as a replacement for nanoparticles to provide protection from harmful ultraviolet rays. This study helps to provide insights into these systems for their potential usage in cosmetics.

  12. Experimental scattering investigations and radiative transfer calculations of large arbitrarily shaped absorbing particles

    Science.gov (United States)

    Sasse, Christian

    1993-12-01

    Measured optical properties of large absorbing arbitrarily shaped particulates are compared to calculated optical properties of smooth homogeneous spheres. The particulates examined are spherical carbon particles with rough surface structure and oil shale. The results of measurements of phase functions of single particles at (lambda) equals 514.5 nm and hemispherical reflectance from 450 to 1959 nm are used in an inverse two-flux model to calculate the average albedo of a single particle. For carbon particles, ideal spheres show a higher forward scatter contribution than measured properties of rough spheres. Two types of oil shale particles with different optical properties but similar size and surface structure are investigated. Particle albedo and phase functions are compared, and the error of measuring the phase function at one wavelength is investigated. Results are also compared to isotropic scattering particles.

  13. Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Zaider, M.

    1992-01-01

    We report on a theory for describing the biological effects of ionizing radiation in particular radon [alpha] particles. Behind this approach is the recognition that biological effects such as chromosome aberrations, cellular transformation, cellular inactivation, etc, are the result of a hierarchic sequence of radiation effects. We indicate how to treat each of the individual processes in this sequence, and also how to relate one effect to the hierarchically superior one.

  14. In-situ cross calibration method for alpha particle loss diagnostics at JET

    Czech Academy of Sciences Publication Activity Database

    Bonheure, G.; Perez Von Thun, Ch.; Reich, M.; Jachmich, S.; Murari, A.; Mlynář, Jan; Hult, M.; Arnold, D.; Dombrowski, T.; Laubenstein, M.; Wieslander, E.; Vidmar, T.; Vermaercke, P.; Cecil, F.E.; Cecconelo, M.; Craciunescu, T.; Darrow, D.; Lerche, E.; Tardocchi, M.; Van Eester, D.; Salmi, A.; Garcia-Munoz, M.; Yavorskij, V.; Popovichev, S.; Koslowski, H.R.; JET EFDA, Contributors.; Pinches, S.D.

    Vol. 33E. Sofia : European Physical Society, 2009 - (Mateev, M.; Benova, E.), P-2.145 ISBN 2-914771-61-4. - (Europhysics conference abstracts). [European Physical Society Conference on Plasma Physics /36th./. Sofia (BG), 29.06.2009-03.07.2009] Institutional research plan: CEZ:AV0Z20430508 Keywords : Tokamak * transport * tritium * in-situ * alpha particles Subject RIV: BL - Plasma and Gas Discharge Physics http://epsppd.epfl.ch/Sofia/pdf/P2_145.pdf

  15. Fission studies with 140 MeV $\\bm{\\alpha}$-Particles

    OpenAIRE

    Buttkewitz, A.; Duhm, H. H.; F. Goldenbaum(Forschungszentrum Jülich, Institut für Kernphysik, Jülich Germany); Machner, W.; Strauß, W.

    2009-01-01

    Binary fission induced by 140 MeV $\\alpha$-particles has been measured for $^{\\rm nat}$Ag, $^{139}$La, $^{165}$Ho and $^{197}$Au targets. The measured quantities are the total kinetic energies, fragment masses, and fission cross sections. The results are compared with other data and systematics. A minimum of the fission probability in the vicinity $Z^2/A=24$ is observed.

  16. A stochastic model of multiple scattering of charged particles: process, transport equation and solutions

    International Nuclear Information System (INIS)

    The process of angular-spatial evolution of multiple scattering of charged particles can be described by a special case of Boltzmann integro-differential equation called Lewis equation. The underlying stochastic process for this evolution is the compound Poisson process on the surface of the unit sphere. The significant portion of events that constitute compound Poisson process that describes multiple scattering have diffusional character. This property allows to analyze the process of angular-spatial evolution of multiple scattering of charged particles as combination of soft and hard collision processes and compute appropriately its transition densities. These computations provide a method of the approximate solution to the Lewis equation. (orig.)

  17. Scattering of massless Dirac particles by oscillating barriers in one dimension

    Energy Technology Data Exchange (ETDEWEB)

    González-Santander, C. [GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain); Domínguez-Adame, F., E-mail: adame@ucm.es [GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain); Fuentevilla, C.H.; Diez, E. [Laboratorio de Bajas Temperaturas, Universidad de Salamanca, E-37008 Salamanca (Spain)

    2014-02-01

    We study the scattering of massless Dirac particles by oscillating barriers in one dimension. Using the Floquet theory, we find the exact scattering amplitudes for time-harmonic barriers of arbitrary shape. In all cases the scattering amplitudes are found to be independent of the energy of the incoming particle and the transmission coefficient is unity. This is a manifestation of the Klein tunneling in time-harmonic potentials. Remarkably, the transmission amplitudes for arbitrary sharply-peaked potentials also become independent of the driving frequency. Conditions for which barriers of finite width can be replaced by sharply-peaked potentials are discussed.

  18. Alpha particles energy estimation from track diameter development in a CR-39 detector.

    Science.gov (United States)

    Azooz, Aassim A; Al-Jubbori, Mushtaq A

    2016-09-01

    The slight nonlinearity in temporal development of tracks diameter in CR-39 nuclear track detectors is examined with the aim of attempting to find if such nonlinearity can be directly related to the charged particle energy. Narrowly spaced etching time-diameter experimental data for alpha particles at five energy values and for one additional energy value etched at five different temperatures are obtained. Initial results show good indication that measuring such time-diameter relationship can form a useful energy estimation tool. Good consistency with other independent published results is obtained. PMID:27341133

  19. Wurtzite Gallium Nitride as a scintillator detector for alpha particles (a Geant4 simulation)

    International Nuclear Information System (INIS)

    Gallium Nitride has become a very popular material in electronics and optoelectronics. Because of its interesting properties, it is suitable for a large range of applications. This material also shows very good scintillation properties that make it a possible candidate for use as a charged particles scintillator detector. In this work, we simulated the scintillation and optical properties of the gallium nitride in the presence of alpha particles using Geant4. The results show that gallium nitride can be an appropriate choice for this purpose

  20. Comparative analysis of inelastic interactions of protons, deuterons, and. cap alpha. particles with nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Barashenkov, V.S.; Zheregi, F.G.; Musul' manbekov, Z.Z.; Plyushchev, V.A.; Solov' eva, Z.I.

    1981-04-01

    Inelastic interactions of protons, deuterons, and ..cap alpha.. particles with emulsion nuclei at 3.6 Gev/nucleon are analyzed within the framework of the cascade-evaporation model. The model accounts well, within the limits of experimental error, for all the principal characteristics measured in experiment; in particular, it explains why the energy of the g protons emitted into the rear hemisphere is independent of the emission angle of these protons, of the mass of the primary particle, and of the degree of spallation of the target nucleus. Some discrepancy with experiment manifests itself only in the details.

  1. Characterization of actinide targets by low solid-angle alpha particle counting

    CERN Document Server

    Denecke, B; Pauwels, J; Robouch, P; Gilliam, D M; Hodge, P; Hutchinson, J M R; Nico, J S

    1999-01-01

    Actinide samples were characterized in an interlaboratory comparison between IRMM and NIST, including alpha-particle counting at defined low solid angle and counting in a 2 pi proportional gas counter. For this comparison, nine sup 2 sup 3 sup 3 UF sub 4 samples with high uniformity in the layer thickness were prepared at IRMM by deposition under vacuum. Polished silicon wafers were used as source substrates, and these were rotated during the deposition using a planetary rotation system. The estimated uncertainties for the defined low solid-angle methods were about 0.1% at both NIST and IRMM. The agreement of reported alpha-particle emission rates in the energy range 2.5-5.09 MeV was better than or equal to 0.02% for the defined solid-angle methods. When comparing total alpha-particle emission rates over the larger energy range 0-9 MeV (which includes all emissions from the daughter nuclides and the impurities), the agreement of the defined solid-angle methods was better than or equal to 0.05%. The 2 pi propo...

  2. Radon and progeny alpha-particle energy analysis using nuclear track methodology

    International Nuclear Information System (INIS)

    A preliminary procedure for alpha-energy analysis of radon and its progeny using nuclear track methodology (NTM) is described in this paper. The method is based on the relationship between alpha-particle energies deposited in polycarbonate material (CR-39) and the track size developed after a well-established chemical etching process. Track geometry, defined by parameters such as major or minor diameters, track area and overall track length, is shown to correlate with alpha-particle energy over the range 6.00 MeV (218Po) to 7.69 MeV (214Po). Track features are measured and the data analyzed automatically using a digital imaging system and commercial PC software. Examination of particle track diameters in CR-39 exposed to environmental radon reveals a multi-modal distribution. Locations of the maxima in this distribution are highly correlated with alphaparticle energies of radon daughters, and the distributions are sufficiently resolved to identify the radioisotopes. This method can be useful for estimating the radiation dose from indoor exposure to radon and its progeny. (author)

  3. Magnetic dynamics of small alpha-Fe2O3 and NiO particles

    DEFF Research Database (Denmark)

    Lefmann, K.; Bødker, Franz; Hansen, Mikkel Fougt; Vazquez, H.; Christensen, N.B.; Clausen, K.N.; Mørup, Steen

    We have studied the magnetic dynamics in nanocrystalline samples of alpha-Fe2O3 (hematite) and NiO by inelastic neutron scattering. By measuring around the structural and the antiferromagnetic reflections, we have probed uniform and staggered magnetic oscillations, respectively. In the hematite...... sign of superparamagnetic relaxation. Studies of the antiferromagnetic signal from NiO also show evidence of collective magnetic excitations, but with a higher energy of the precession state than for hematite. The inelastic signal at the structural reflection of NiO presents evidence for uniform...

  4. Spin scattering of a particle for periodic boundary conditions

    OpenAIRE

    Chu, L. L.; Yu, K. W.

    2001-01-01

    We have studied anomalous diffusion of a particle in a random medium in which the passage of the particle may modify the state of the visited sites. The simplicity of the dynamics allows analytic solution. Interesting propagation and organization behaviors will be reported.

  5. Experimental scattering matrices of clouds and randomly oriented particles

    NARCIS (Netherlands)

    O. Muñoz; J.W. Hovenier

    2015-01-01

    In the atmospheres of planets and satellites, liquid particles may occur in the form of clouds, hazes, fog, and rain. The liquid can be water as is the case in the atmosphere of the Earth but also other materials, like sulfuric acid that occurs in the atmosphere of Venus. These liquid particles can

  6. Features in the angular structure of light scattered by a layer of partially ordered soft particles

    International Nuclear Information System (INIS)

    The angular structure of light scattered by layers with a high concentration of monodisperse optically soft spherical particles has been analyzed using the interference approximation to describe the collective scattering effects, the radiative transfer theory to describe the light field in the layer, and the Mie theory to describe the characteristics of scattering by an individual particle.It has been shown that in the close-packed layers of optically soft particles an additional maximum on the angular dependence of light transmitted through the layer can be observed, if the phase function has a minimum at zero scattering angle due to the partial ordering of scatterers. It takes place at a scattering angle coinciding with the direction of the incident light. If the phase function of a concentrated layer has a primary maximum at scattering angles larger than 45-bar , then an additional maximum in the backscattered light can be observed. Its position is determined by the maximum location on the scattering phase function. The luminance values at the maxima can exceed those at nearby angles by a factor of about one and a haft

  7. Giant In-Particle Field Concentration and Fano Resonances at Light Scattering by High-Refractive Index Particles

    CERN Document Server

    Tribelsky, M I

    2015-01-01

    A detailed analytical inspection of light scattering by a particle with high refractive index m+i\\kappa and small dissipative constant \\kappa is presented. We have shown that there is a dramatic difference in the behavior of the electromagnetic field within the particle (inner problem) and the scattered field outside it (outer problem). With an increase in m at fix values of the other parameters, the field within the particle asymptotically converges to a periodic function of m. The electric and magnetic type Mie resonances of different orders overlap substantially. It may lead to a giant concentration of the electromagnetic energy within the particle. At the same time, we demonstrate that identical transformations of the solution for the outer problem allow to present each partial scattered wave as a sum of two partitions. One of them corresponds to the m-independent wave, scattered by a perfectly reflecting particle and plays the role of a background, while the other is associated with the excitation of a s...

  8. The impact of organic coatings on light scattering by sodium chloride particles

    Science.gov (United States)

    Li, Yan; Ezell, Michael J.; Finlayson-Pitts, Barbara J.

    2011-08-01

    Light scattering by airborne particles plays a major role in visibility degradation and climate change. The composition and structure of particles in air can be complex, so that predictions of light scattering a priori have significant uncertainties. We report here studies of light scattering by NaCl, a model for airborne salt particles from the ocean and alkaline lakes, with and without an organic coating formed from the low volatility products of the reaction of α-pinene with ozone at room temperature at 1 atm in air. Light scattering at 450, 550 and 700 nm was measured using an integrating nephelometer on particles whose size distribution was independently determined using a scanning mobility particle sizer (SMPS). For comparison, polystyrene latex spheres (PSL) of a known size and dioctylphthalate (DOP) particles generated with a narrow size distribution were also studied. The measured values were compared to those calculated using Mie theory. Although excellent agreement between experiment and theory was found for the PSL and DOP particles, there were large discrepancies for a polydisperse NaCl sample. These were traced to errors in the size distribution measurements. Despite the use of 85Kr neutralizers, the Boltzmann charge equilibrium distribution assumption used to derive particle size distributions from SMPS data was shown not to be valid, leading to an overestimate of the concentration of larger particles and their contribution to light scattering. Correcting for this, the combination of experiments and theory show that as salt takes up low volatility organics in the atmosphere and the geometric mean diameter increases, the effect on light scattering may be reasonably approximated from the change in size distribution under conditions where the organic coating is small relative to the core size. However, for a given particle diameter, light scattering decreases as the relative contribution of the organic component increases. Thus, light scattering by

  9. Light scattering of PMMA latex particles in benzene: structural effects

    NARCIS (Netherlands)

    Nieuwenhuis, E.A.; Vrij, A.

    1979-01-01

    Intra- and interparticle structural effects were studied in polymethylmethacrylate (PMMA) latex dispersions in a nonpolar solvent with the technique of light scattering. The required transparency of the dispersions was attained by a close matching of the refractive index of PMMA and solvent, for whi

  10. Light Scattering and Thermal Emission by Primitive Dust Particles in Planetary Systems

    CERN Document Server

    Kimura, Hiroshi; Li, Aigen; Lebreton, Jérémy

    2016-01-01

    This review focuses on numerical approaches to deducing the light-scattering and thermal-emission properties of primitive dust particles in planetary systems from astronomical observations. The particles are agglomerates of small grains with sizes comparable to visible wavelength and compositions being mainly magnesium-rich silicates, iron-bearing metals, and organic refractory materials in pristine phases. These unique characteristics of primitive dust particles reflect their formation and evolution around main-sequence stars of essentially solar composition. The development of light-scattering theories has been offering powerful tools to make a thorough investigation of light scattering and thermal emission by primitive dust agglomerates in such a circumstellar environment. In particular, the discrete dipole approximation, the T-matrix method, and effective medium approximations are the most popular techniques for practical use in astronomy. Numerical simulations of light scattering and thermal emission by ...

  11. Magnetization anomalies of fine particles interpreted as surface effects by inelastic neutron scattering

    International Nuclear Information System (INIS)

    Inelastic neutron scattering experiments on small Fe particles (R=12 Angstrom) reveal that some part of the magnetic intensity is paramagnetic at 300 K. As T decreases it freezes and develops short range ferromagnetic correlations. It is attributed to spins at the particle surface. (authors). 3 figs., 5 refs

  12. Effective-range approximation for scattering of a particle with nonzero orbital angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Drukarev, G.F.

    1981-02-01

    A study is made of scattering of a slow particle by a potential well capable of holding a weakly bound particle with given orbital angular momentum. On this basis, an effective-range approximation is constructed for nonzero orbital angular momentum.

  13. Scattering of Bessel beam by arbitrarily shaped composite particles with core–shell structure

    International Nuclear Information System (INIS)

    This study investigates the scattering of Bessel beam by composite particles with core–shell structure. Specifically, the vector expressions of zero-th order Bessel beam that satisfy well Maxwell's equations in combination with the rotation Euler angles are used to represent the arbitrarily incident Bessel beams. An efficient numerical method based on surface integral equations is introduced to formulate the scattering problems involving arbitrarily shaped composite particles with core–shell structure. Solutions are performed iteratively by using the multilevel fast multipole algorithm. The numerical results for differential scattering cross sections of several selected composite particles are presented and analyzed. This investigation is expected to provide useful guidance for techniques of laser detection on particle, diagnosis, and manipulation. - Highlights: • The scattering of Bessel beam by composite particles is numerically investigated. • A detailed description of the arbitrarily incident Bessel beam is presented. • The surface integral equation method is used to solve the studied scattering problem. • The numerical results of several typical composite particles are presented

  14. Measurements of Particle Size Distribution Based on Mie Scattering Theory and Markov Chain Inversion Algorithm

    Directory of Open Access Journals (Sweden)

    Zi Ye

    2012-10-01

    Full Text Available Measuring particle size distribution through calculating light scattering intensity is a typical inverse problem. This paper builds an inverse mathematical model based on Mie scattering, deduces the inversion formulas for particle size, and calculates the relative coefficients through programming with built-in functions in MATLAB. In order to improve the accuracy and noise immunity of particle size distribution measurement, the development of stochastic inversion algorithm: an inverse problem model based on Markov chain algorithm is proposed. Results of numerical simulation are added acceptable noise indicate that the algorithm of Markov chain has strong noise immunity and can meet the requirements of on-line measurement.

  15. Light amplification and scattering by clusters made of small active particles: the local perturbation approach

    CERN Document Server

    Prosentsov, V V

    2013-01-01

    The light amplification by finite active media is used extensively in modern optics applications. In this paper the light amplification and scattering by cluster of small particles is studied analytically and numerically with the help of the local perturbation method and phenomenological laser theory. It is shown that light amplification is possible even for one small particle, and that the amplification is more profound when the light frequency nears the frequency of the cluster's morphological resonance. Theoretical discussions are supplemented by numerical results for scattering by clusters which particles positioned at ordered and at slightly disordered positions.

  16. Stability of the Global Alfven Eigenmode in the presence of fusion alpha particles in an ignited tokamak plasma

    International Nuclear Information System (INIS)

    The stability of the Global Alfven Eigenmodes is investigated in the presence of super-Alfvenic energetic particles, such as the fusion-product alpha particles in an ignited deuterium-tritium tokamak plasma. Alpha particles tend to destabilize these modes when ω*α > ωA, where ωA is the shear-Alfven modal frequency and ω*α is the alpha particle diamagnetic drift frequency. This destabilization due to alpha particles is found to be significantly enhanced when the alpha particles are modeled with a slowing-down distribution function rather than with a Maxwellian. However, previously neglected electron damping due to the magnetic curvature drift is found to be comparable in magnitude to the destabilizing alpha particle term. Furthermore, the effects of toroidicity are also found to be stabilizing, since the intrinsic toroidicity induces poloidal mode coupling, which enhances the parallel electron damping from the sideband shear-Alfven Landau resonance. In particular, for the parameters of the proposed Compact Ignition Tokamak, the Global Alfven Eigenmodes are found to be completely stabilized by either the electron damping that enters through the magnetic curvature drift or the damping introduced by finite toroidicity. 29 refs., 8 figs., 1 tab

  17. Characterization of spherical core–shell particles by static light scattering. Estimation of the core- and particle-size distributions

    International Nuclear Information System (INIS)

    A numerical method is proposed for the characterization of core–shell spherical particles from static light scattering (SLS) measurements. The method is able to estimate the core size distribution (CSD) and the particle size distribution (PSD), through the following two-step procedure: (i) the estimation of the bivariate core–particle size distribution (C–PSD), by solving a linear ill-conditioned inverse problem through a generalized Tikhonov regularization strategy, and (ii) the calculation of the CSD and the PSD from the estimated C–PSD. First, the method was evaluated on the basis of several simulated examples, with polystyrene–poly(methyl methacrylate) core–shell particles of different CSDs and PSDs. Then, two samples of hematite–Yttrium basic carbonate core–shell particles were successfully characterized. In all analyzed examples, acceptable estimates of the PSD and the average diameter of the CSD were obtained. Based on the single-scattering Mie theory, the proposed method is an effective tool for characterizing core–shell colloidal particles larger than their Rayleigh limits without requiring any a-priori assumption on the shapes of the size distributions. Under such conditions, the PSDs can always be adequately estimated, while acceptable CSD estimates are obtained when the core/shell particles exhibit either a high optical contrast, or a moderate optical contrast but with a high ‘average core diameter’/‘average particle diameter’ ratio. -- Highlights: ► Particles with core–shell morphology are characterized by static light scattering. ► Core size distribution and particle size distribution are successfully estimated. ► Simulated and experimental examples are used to validate the numerical method. ► The positive effect of a large core/shell optical contrast is investigated. ► No a-priori assumption on the shapes of the size distributions is required.

  18. Particle size distribution models of small angle neutron scattering pattern on ferro fluids

    International Nuclear Information System (INIS)

    The Fe3O4 ferro fluids samples were synthesized by a co-precipitation method. The investigation of ferro fluids microstructure is known to be one of the most important problems because the presence of aggregates and their internal structure influence greatly the properties of ferro fluids. The size and the size dispersion of particle in ferro fluids were determined assuming a log normal distribution of particle radius. The scattering pattern of the measurement by small angle neutron scattering were fitted by the theoretical scattering function of two limitation models are log normal sphere distribution and fractal aggregate. Two types of particle are detected, which are presumably primary particle of 30 Armstrong in radius and secondary fractal aggregate of 200 Armstrong with polydispersity of 0.47 up to 0.53. (author)

  19. Generalized Fokker-Planck Approximations of Particle Transport with Highly Forward-Peaked Scattering

    International Nuclear Information System (INIS)

    The Fokker-Planck equation is often used to approximate the description of particle transport processes with highly forward-peaked scattering. Pomraning has shown that if the physical scattering kernel is sufficiently dominated by small-angle scattering, then the Fokker-Planck equation is an asymptotic approximation to the linear Boltzmann equation. However, most physically-meaningful scattering kernels contain a sufficient amount of large-angle scattering that the asymptotic criterion is not met. Thus, in many physical problems, solutions of the Fokker-Planck equation are substantially in error. In this paper, Pomraning's asymptotic results are generalized and a new generalized Fokker-Planck (GFP) theory that robustly incorporates large-angle scattering is developed. Numerical experiments demonstrate that the resulting GFP equations are much more accurate than the standard Fokker-Planck equation

  20. Shape sensitive Raman scattering from Nano-particles

    CERN Document Server

    Apell, S P; Antosiewicz, Tomasz; Aizpurua, J

    2016-01-01

    We investigate the interplay of shape changes and localized surface plasmons in small metal particles with the potential of a large enhancement of the Raman signal from the particles own vibrations. The framework is a geometrical one where we study the change in geometric factors during the vibrational movement. The resulting cross-section is found to be of a detectable order of magnitude however much smaller than the elastic cross-section.

  1. Light scattering study of the diffusion of interacting particles

    OpenAIRE

    Finsy, R.; Devriese, A.; Lekkerkerker, H.N.W.

    1980-01-01

    The diffusion coefficient of a water-in-oil microemulsion has been measured as a function of the concentration of the suspended particles using photon correlation techniques. The data have been analysed using an extension of the thermo-hydrodynamic theory of G. K. Batchelor to the case of a potential of mean force between particles which consists of a hard-core repulsion and an attractive part. The parameters for this potential are consistent with those obtained from the osmotic compressibili...

  2. Lattice operators for scattering of particles with spin

    CERN Document Server

    Prelovsek, S; Lang, C B

    2016-01-01

    We construct operators for simulating the scattering of two hadrons with spin on the lattice. Three methods are shown to give the consistent operators for PN, PV, VN and NN scattering, where P, V and N denote pseudoscalar, vector and nucleon. Explicit expressions for operators are given for all irreducible representations at lowest two relative momenta. Each hadron has a good helicity in the first method. The hadrons are in a certain partial wave L with total spin S in the second method. These enable the physics interpretations of the operators obtained from the general projection method. The correct transformation properties of the operators in all three methods are proven. The total momentum of two hadrons is restricted to zero since parity is a good quantum number in this case.

  3. Nonrelativistic Charged Particle-Magnetic Monopole Scattering in the Global Monopole Background

    CERN Document Server

    De Oliveira, A L C

    2003-01-01

    We analyze the nonrelativistic quantum scattering problem of a charged particle by an Abelian magnetic monopole in the background of a global monopole. In addition to the magnetic and geometric effects, we consider the influence of the electrostatic self-interaction on the charged particle. Moreover, for the specific case where the electrostatic self-interaction becomes attractive, charged particle-monopole bound system can be formed and the respective energy spectrum is hydrogen-like one.

  4. Measuring of filtration efficiency of nonwoven textiles in volume from scattered light by seeding particles

    OpenAIRE

    Sidlof P.; Bilek P.

    2013-01-01

    This paper deals with the method which calculates a filtration efficiency of nonwoven textiles from scattered light intensity by seeding particles. Thefiltration efficiency is commonly measured by particle counters. Samples of liquid or gas are taken during a test in front of and behind a filtration material. The concentration of particles is measured and the filtration efficiency is calculated. The filtration efficiency does not have to be uniform in itswhole surface. The uniformity of filtr...

  5. Some characteristics of the CR-39 solid state nuclear-track detector for protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Experimental results related to certain registration properties of the CR-39 solid state nuclear-track detector for charged particles are presented and discussed. The determination of the CR-39 chemical etching in NaOH and KOH solutions, comprising concentration (2-10N) and temperature effects (50-900C), showed the existence of an inverse proportion between the induction time and the temperature as well as the normal concentration of the solutions. The critical energy and the critical energy-loss rate of CR-39 track detectors for registration of protons were experimentally determined. A number of samples was exposed to 24MeV proton beams in the IEN-CNEN Cyclotron (CV-28), using a scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy for 16h and 24h chemical etching (6.25 NaOH, 700C), and considering 1.5 μm as the minimum observable track-diameter, the values (21.0 + - 1.5) MeV and (22.5 + - 1.5) MeV were deduced, respectively, for the critical energy. From the calculated energy-loss rate versus energy curve, the critical energy-loss rate was evaluated as 24 + - 2 MeV.cm2/g. Finally, the CR-39 response for low energy alpha particles (E < = 6 MeV) was studied. It was demonstrated also that successive chemical etchings do not produce the same track geometry as obtained by means of a continuous revelation with the same total etching time. (Author)

  6. Particle-in-cell simulations of the magnetoacoustic cyclotron instability of fusion-born alpha-particles in tokamak plasmas

    Science.gov (United States)

    Cook, J. W. S.; Dendy, R. O.; Chapman, S. C.

    2013-06-01

    Ion cyclotron emission (ICE) is the only collective radiative instability, driven by confined fusion-born alpha-particles, observed from deuterium-tritium (DT) plasmas in both JET and TFTR. Using first principles particle-in-cell simulations of the magnetoacoustic cyclotron instability (MCI), we elucidate some of the fully kinetic nonlinear processes that may underlie observations of ICE from fusion products in these large tokamaks. We find that the MCI is intrinsically self-limiting on very fast timescales, which may help explain the observed correlation between linear theory and observed ICE intensity. The simulations elaborate the nature of the excited electric and magnetic fluctuations, from first principles, confirming the dominant role of fast Alfvénic and electrostatic components which is assumed ab initio in analytical treatments.

  7. Scattering of twisted particles: Extension to wave packets and orbital helicity

    International Nuclear Information System (INIS)

    High-energy photons and other particles carrying nonzero orbital angular momentum (OAM) emerge as a new tool in high-energy physics. Recently, it was suggested to generate high-energy photons with nonzero OAM (twisted photons) by the Compton backscattering of twisted optical photons on relativistic electron beams. Twisted electrons in the intermediate energy range have also been demonstrated experimentally; twisted protons and other particles can, in principle, be created in a similar way. Collisions of energetic twisted states can offer a new look at particle properties and interactions. A theoretical description of twisted particle scattering developed previously treated them as pure Bessel states and ran into difficulty when describing the OAM of the final twisted particle at nonzero scattering angles. Here we develop further this formalism by incorporating two additional important features. First, we treat the initial OAM state as a wave packet of a finite transverse size rather than a pure Bessel state. This realistic assumption allows us to resolve the existing controversy between two theoretical analyses for nonforward scattering. Second, we describe the final twisted particle in terms of the orbital helicity: the OAM projection on its average direction of propagation rather than on the fixed reaction axis. Using this formalism, we determine to what extent the twisted state is transferred from the initial to final OAM particle in a generic scattering kinematics. As a particular application, we prove that in the Compton backscattering the orbital helicity of the final photon stays close to the OAM projection of the initial photon.

  8. Scattering of twisted particles: Extension to wave packets and orbital helicity

    Science.gov (United States)

    Ivanov, I. P.; Serbo, V. G.

    2011-09-01

    High-energy photons and other particles carrying nonzero orbital angular momentum (OAM) emerge as a new tool in high-energy physics. Recently, it was suggested to generate high-energy photons with nonzero OAM (twisted photons) by the Compton backscattering of twisted optical photons on relativistic electron beams. Twisted electrons in the intermediate energy range have also been demonstrated experimentally; twisted protons and other particles can, in principle, be created in a similar way. Collisions of energetic twisted states can offer a new look at particle properties and interactions. A theoretical description of twisted particle scattering developed previously treated them as pure Bessel states and ran into difficulty when describing the OAM of the final twisted particle at nonzero scattering angles. Here we develop further this formalism by incorporating two additional important features. First, we treat the initial OAM state as a wave packet of a finite transverse size rather than a pure Bessel state. This realistic assumption allows us to resolve the existing controversy between two theoretical analyses for nonforward scattering. Second, we describe the final twisted particle in terms of the orbital helicity: the OAM projection on its average direction of propagation rather than on the fixed reaction axis. Using this formalism, we determine to what extent the twisted state is transferred from the initial to final OAM particle in a generic scattering kinematics. As a particular application, we prove that in the Compton backscattering the orbital helicity of the final photon stays close to the OAM projection of the initial photon.

  9. Giant in-particle field concentration and Fano resonances at light scattering by high-refractive-index particles

    Science.gov (United States)

    Tribelsky, Michael I.; Miroshnichenko, Andrey E.

    2016-05-01

    We present the results of a detailed analytical study of light scattering by a particle with high refractive index m +i κ and low losses (m ≫1 ,0 academic interest, the obtained results may be employed to design new highly nonlinear heterogenic nanostructures and other metamaterials.

  10. Light Scattering by Gaussian Particles: A Solution with Finite-Difference Time Domain Technique

    Science.gov (United States)

    Sun, W.; Nousiainen, T.; Fu, Q.; Loeb, N. G.; Videen, G.; Muinonen, K.

    2003-01-01

    The understanding of single-scattering properties of complex ice crystals has significance in atmospheric radiative transfer and remote-sensing applications. In this work, light scattering by irregularly shaped Gaussian ice crystals is studied with the finite-difference time-domain (FDTD) technique. For given sample particle shapes and size parameters in the resonance region, the scattering phase matrices and asymmetry factors are calculated. It is found that the deformation of the particle surface can significantly smooth the scattering phase functions and slightly reduce the asymmetry factors. The polarization properties of irregular ice crystals are also significantly different from those of spherical cloud particles. These FDTD results could provide a reference for approximate light-scattering models developed for irregular particle shapes and can have potential applications in developing a much simpler practical light scattering model for ice clouds angular-distribution models and for remote sensing of ice clouds and aerosols using polarized light. (copyright) 2003 Elsevier Science Ltd. All rights reserved.

  11. Self-consistent analysis of alpha-particle heating of a fast-solenoid plasma

    International Nuclear Information System (INIS)

    A numerical technique has been developed to analyse the dynamics of a linear, magnetically confined plasma column and its associated fusion-produced alpha-particles in a self consistent manner. The thermonuclear background plasma is considered as a radially non-uniform, axially symmetric magnetofluid in pressure equilibrium with the surrounding axial magnetic field. A multi-group technique is utilized to examine the alphas as a collection of particles distributed among a continuous spectrum of confined orbits. The technique is shown to be an effective one for observing the interaction between super-thermal particles with large orbit sizes and a stable plasma of comparable size. The use of a distribution function in an adiabatic-invariant representation results in an enormous increase in the time scale which can be treated. This enables analysis of the entire duty cycle of a laser solenoid plasma in reasonable computation times. An analysis of a fast solenoid plasma is described, where the initial plasma radius and temperature are varied parametrically. A plasma column of radius 7mm, temperature 6keV, and β=0.95 will reach an ion temperature of 10keV, corresponding to a fusion energy gain of 8, after 3ms. A range of maximum gain occurs for initial temperatures of 5 to 7keV, with larger radius plasmas more favoured by the cooler limits. The effect of increasing the alpha-particle-electron energy transfer rate by a moderate amount to account for anomalous effects is to increase the plasma temperature at longer times, as long as this energy transfer is well-coupled to the electron-ion energy transfer. Increasing the rate at which plasma transport processes occur (''anomalous transport'') always results in lower fusion yield, because of rapid plasma diffusion. (author)

  12. The single scattering properties of the aerosol particles as aggregated spheres

    Science.gov (United States)

    Wu, Y.; Gu, X.; Cheng, T.; Xie, D.; Yu, T.; Chen, H.; Guo, J.

    2012-08-01

    The light scattering and absorption properties of anthropogenic aerosol particles such as soot aggregates are complicated in the temporal and spatial distribution, which introduce uncertainty of radiative forcing on global climate change. In order to study the single scattering properties of anthorpogenic aerosol particles, the structures of these aerosols such as soot paticles and soot-containing mixtures with the sulfate or organic matter, are simulated using the parallel diffusion limited aggregation algorithm (DLA) based on the transmission electron microscope images (TEM). Then, the single scattering properties of randomly oriented aerosols, such as scattering matrix, single scattering albedo (SSA), and asymmetry parameter (AP), are computed using the superposition T-matrix method. The comparisons of the single scattering properties of these specific types of clusters with different morphological and chemical factors such as fractal parameters, aspect ratio, monomer radius, mixture mode and refractive index, indicate that these different impact factors can respectively generate the significant influences on the single scattering properties of these aerosols. The results show that aspect ratio of circumscribed shape has relatively small effect on single scattering properties, for both differences of SSA and AP are less than 0.1. However, mixture modes of soot clusters with larger sulfate particles have remarkably important effects on the scattering and absorption properties of aggregated spheres, and SSA of those soot-containing mixtures are increased in proportion to the ratio of larger weakly absorbing attachments. Therefore, these complex aerosols come from man made pollution cannot be neglected in the aerosol retrievals. The study of the single scattering properties on these kinds of aggregated spheres is important and helpful in remote sensing observations and atmospheric radiation balance computations.

  13. The single scattering properties of the aerosol particles as aggregated spheres

    International Nuclear Information System (INIS)

    The light scattering and absorption properties of anthropogenic aerosol particles such as soot aggregates are complicated in the temporal and spatial distribution, which introduce uncertainty of radiative forcing on global climate change. In order to study the single scattering properties of anthorpogenic aerosol particles, the structures of these aerosols such as soot paticles and soot-containing mixtures with the sulfate or organic matter, are simulated using the parallel diffusion limited aggregation algorithm (DLA) based on the transmission electron microscope images (TEM). Then, the single scattering properties of randomly oriented aerosols, such as scattering matrix, single scattering albedo (SSA), and asymmetry parameter (AP), are computed using the superposition T-matrix method. The comparisons of the single scattering properties of these specific types of clusters with different morphological and chemical factors such as fractal parameters, aspect ratio, monomer radius, mixture mode and refractive index, indicate that these different impact factors can respectively generate the significant influences on the single scattering properties of these aerosols. The results show that aspect ratio of circumscribed shape has relatively small effect on single scattering properties, for both differences of SSA and AP are less than 0.1. However, mixture modes of soot clusters with larger sulfate particles have remarkably important effects on the scattering and absorption properties of aggregated spheres, and SSA of those soot-containing mixtures are increased in proportion to the ratio of larger weakly absorbing attachments. Therefore, these complex aerosols come from man made pollution cannot be neglected in the aerosol retrievals. The study of the single scattering properties on these kinds of aggregated spheres is important and helpful in remote sensing observations and atmospheric radiation balance computations.

  14. Geometrical Analysis of Small Angle Scattering from Lamellar and Cylindrical Particles by Indirect Transformation Method

    International Nuclear Information System (INIS)

    The data treatment results of the small angle scattering from lamellar and cylindrical particles by indirect transformation method has been geometrically analized. Presented the theory of small angle scattering from lamellar and cylindrical particles that gives the cross section scattering function in the reciprocal space and the distance distribution function in the real space. Also discussed the features of the indirect transformation method compare to the conventional method that is the direct transformation method. Presented the data treatment results of the cylindrical particles cross section scattering from the data treatment results of the cylindrical particles scattering. The calculation of the parameters from the two of data sets give values of cross section intensity at zero angle It (0) = 0.53640, and Ic (0) = 151.51, cross sections of radius of gyration Rt = 11.461oA and Rc = 13.908oA and the maximum diameter of the cross sections Dt (max) = 40oA and Dc (max) = 40oA of lamellar and cylindrical particles, respectively. (author)

  15. Estimation of the {alpha} particles and neutron distribution generated during a fusion reaction; Evaluation de la distribution des particules {alpha} et des neutrons issus de la reaction de fusion

    Energy Technology Data Exchange (ETDEWEB)

    Dellacherie, S.

    1997-12-01

    The respective distributions (or density probabilities) of {alpha} particles and neutrons have been modeled using a Monte-Carlo method for the thermonuclear fusion reaction D + T {yields} {alpha} + n + 17.6 MeV. (N.T.).

  16. Mechanistic model of radon-induced lung cancer risk at low exposure levels based on cellular alpha particle hits

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Hofmann; Hatim, Fakir [Salzburg Univ., Div. of Physics and Biophysics, Dept. of Material Science (Austria); Lucia-Adina, Truta-Popa [Babes-Bolyai Univ., Faculty of Physics (Romania)

    2006-07-01

    To explore the role of the multiplicity of cellular hits by radon progeny alpha particles for lung cancer incidence, the number of single and multiple alpha particle hits were computed for basal and secretory cells in the bronchial epithelium of human airway bifurcations employing Monte Carlo methods. Hot spots of alpha particle hits were observed at the branching points of bronchial airway bifurcations, suggesting that multiple alpha particle hits may occur primarily at carinal ridges. Random alpha particle intersections of bronchial cells during a given exposure period, selected from a Poisson distribution, were simulated by an initiation-promotion model, based on experimentally observed cellular transformation and survival functions. To consider potential bystander effects, which have been observed in cellular in vitro studies, alpha particle interactions were also simulated for larger sensitive target volumes in bronchial epithelium, consisting of a collection of cells. Lung cancer risk simulations indicated that cancer induction for continuous exposures is related to the cycle time of an irradiated cell, thus exhibiting a distinct dose-rate effect. While the dominant role of single hits leads to a linear dose-response relationship at low radon exposure levels, predicted lung cancer risk for a collection of interacting cells exhibits a linear-quadratic response, suggesting that bystander effects, if operating at all under in vivo irradiations, may be restricted to a small number of adjacent cells. (author)

  17. Mechanistic model of radon-induced lung cancer risk at low exposure levels based on cellular alpha particle hits

    International Nuclear Information System (INIS)

    To explore the role of the multiplicity of cellular hits by radon progeny alpha particles for lung cancer incidence, the number of single and multiple alpha particle hits were computed for basal and secretory cells in the bronchial epithelium of human airway bifurcations employing Monte Carlo methods. Hot spots of alpha particle hits were observed at the branching points of bronchial airway bifurcations, suggesting that multiple alpha particle hits may occur primarily at carinal ridges. Random alpha particle intersections of bronchial cells during a given exposure period, selected from a Poisson distribution, were simulated by an initiation-promotion model, based on experimentally observed cellular transformation and survival functions. To consider potential bystander effects, which have been observed in cellular in vitro studies, alpha particle interactions were also simulated for larger sensitive target volumes in bronchial epithelium, consisting of a collection of cells. Lung cancer risk simulations indicated that cancer induction for continuous exposures is related to the cycle time of an irradiated cell, thus exhibiting a distinct dose-rate effect. While the dominant role of single hits leads to a linear dose-response relationship at low radon exposure levels, predicted lung cancer risk for a collection of interacting cells exhibits a linear-quadratic response, suggesting that bystander effects, if operating at all under in vivo irradiations, may be restricted to a small number of adjacent cells. (author)

  18. Measuring the complex field scattered by single submicron particles

    Energy Technology Data Exchange (ETDEWEB)

    Potenza, Marco A. C., E-mail: marco.potenza@unimi.it; Sanvito, Tiziano [Department of Physics, University of Milan, via Celoria, 16 – I-20133 Milan (Italy); CIMAINA, University of Milan, via Celoria, 16 – I-20133 Milan (Italy); EOS s.r.l., viale Ortles 22/4, I-20139 Milan (Italy); Pullia, Alberto [Department of Physics, University of Milan, via Celoria, 16 – I-20133 Milan (Italy)

    2015-11-15

    We describe a method for simultaneous measurements of the real and imaginary parts of the field scattered by single nanoparticles illuminated by a laser beam, exploiting a self-reference interferometric scheme relying on the fundamentals of the Optical Theorem. Results obtained with calibrated spheres of different materials are compared to the expected values obtained through a simplified analytical model without any free parameters, and the method is applied to a highly polydisperse water suspension of Poly(D,L-lactide-co-glycolide) nanoparticles. Advantages with respect to existing methods and possible applications are discussed.

  19. Disturbance from Am-241 Photons of the Cellular Dose by Am-241 Alpha Emissions: Am-241 as an alternative source of alpha particles to radon daughters

    International Nuclear Information System (INIS)

    The Radiation Bioengineering Laboratory (RadBio Lab) at Seoul National University (SNU) has built an Am-241 alpha particle irradiator for study of cellular responses to radiation from radon daughters. The radon daughters of concern that cause internal exposure from inhalation of radon-contaminated air are Po-218, Po-214 and Po-210. In their alpha decay schemes, the yields of photon emissions are negligible. Unfortunately, Am-241, the source of alpha irradiator in RadBio Lab, emits photons at every alpha decay while transforming to Np-237 of long half-life. Employing Am-241 as the source simulating radon daughters, therefore, requires that photon emissions from Am-241 be specified in term of dose contribution. In this study, Monte Carlo calculations have been made to characterize dose contributions of Am-241 photon emissions. This study confirms that disturbance from Am-241 photon emissions of the cellular dose by Am-241 alpha emissions is negligible. Dose contamination fraction from photon emissions was 8.02 .. 10-6 at 25 mm SSD at maximum. Also, note that LET in tissue-equivalent medium varies within about 20% for alpha particles at energies over 5 MeV

  20. Disturbance from Am-241 Photons of the Cellular Dose by Am-241 Alpha Emissions: Am-241 as an alternative source of alpha particles to radon daughters

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki-Man; Kim, Eun-Hee [Seoul National University, Seoul (Korea, Republic of)

    2015-05-15

    The Radiation Bioengineering Laboratory (RadBio Lab) at Seoul National University (SNU) has built an Am-241 alpha particle irradiator for study of cellular responses to radiation from radon daughters. The radon daughters of concern that cause internal exposure from inhalation of radon-contaminated air are Po-218, Po-214 and Po-210. In their alpha decay schemes, the yields of photon emissions are negligible. Unfortunately, Am-241, the source of alpha irradiator in RadBio Lab, emits photons at every alpha decay while transforming to Np-237 of long half-life. Employing Am-241 as the source simulating radon daughters, therefore, requires that photon emissions from Am-241 be specified in term of dose contribution. In this study, Monte Carlo calculations have been made to characterize dose contributions of Am-241 photon emissions. This study confirms that disturbance from Am-241 photon emissions of the cellular dose by Am-241 alpha emissions is negligible. Dose contamination fraction from photon emissions was 8.02 .. 10{sup -6} at 25 mm SSD at maximum. Also, note that LET in tissue-equivalent medium varies within about 20% for alpha particles at energies over 5 MeV.

  1. A cluster expansion for bound three-alpha particles as a three-body problem

    International Nuclear Information System (INIS)

    A three-body model is proposed to study the nuclear bound states. The nucleus is described as a bound state of three clusters. A cluster expansion is introduced for the three cluster bound state problem. The present integral equations are treated by simple approximate solutions, which lead to effective potentials by using the present cluster expansion. The 12C nucleus is described as a three-alpha particle bound state. The binding energy of 12C is calculated numerically using the present cluster expansion as bound three-alpha clusters. The present three-body cluster expansion calculations are very near to the exact three-body calculations using separable potentials. The present theoretical calculations are in good agreement with the experimental measurements. (author)

  2. Coulomb excitation effects on alpha-particle optical potential below the Coulomb barrier

    CERN Document Server

    Avrigeanu, V; Mănăilescu, C

    2016-01-01

    A competition of the low-energy Coulomb excitation (CE) with the compound nucleus (CN) formation in alpha-induced reactions below the Coulomb barrier has recently been assumed in order to make possible the description of the latter as well as the alpha-particle emission by the same optical model (OM) potential. On the contrary, we show in the present work that the corresponding partial waves and integration radii provide evidence for the distinct account of the CE cross section and OM total-reaction cross section $\\sigma_R$. Thus the largest contribution to CE cross section comes by far from partial waves larger than the ones contributing to the $\\sigma_R$ values.

  3. Light scattering study of the diffusion of interacting particles

    NARCIS (Netherlands)

    Finsy, R.; Devriese, A.; Lekkerkerker, H.N.W.

    1980-01-01

    The diffusion coefficient of a water-in-oil microemulsion has been measured as a function of the concentration of the suspended particles using photon correlation techniques. The data have been analysed using an extension of the thermo-hydrodynamic theory of G. K. Batchelor to the case of a potentia

  4. Ultra-directional super-scattering of homogenous spherical particles with radial anisotropy

    CERN Document Server

    Liu, Wei

    2015-01-01

    We study the light scattering of homogenous radially-anisotropic spherical particles. It is shown that radial anisotropy can be employed to tune effectively the electric resonances, and thus enable flexible overlapping of electric and magnetic dipoles of various numbers, which leads to unidirectional forward super-scattering at different spectral positions. We further reveal that through adjusting the radial anisotropy parameters, electric and magnetic resonances of higher orders can be also made overlapped, thus further collimating the forward scattering lobes. The ultra-directional super-scattering we have obtained with individual homogenous radially anisotropic spherical particles may shed new light to the design of compact and efficient nanoantennas, which may find various applications in solar cells, bio-sensing and many other antenna based researches.

  5. Immuno-vectorization of radioelements emitters of alpha particles: a new therapy in cancerology

    International Nuclear Information System (INIS)

    The radio-immunotherapy is an anti cancerous therapy which consists in vectorising with immuno-specific agents very radio toxic radioelements on tumors or in their environment to destroy them. The first part of this report presents the different characteristics of antibodies as well as their means of production under monoclonal shapes specifically steered against a tumoral antigen of interest. The second part of this report replaces the importance of the immunological vectors in the context of the nuclear medicine. It is notably described that the different methods which allow to radio-label the vector, as well as the different ways of optimization which were envisaged to improve the targeting of radioelements on a tumor. These different developments allow to define the potential place of the alpha radio-immunotherapy in treatments and so re-place the interest of the experimental part. If the radio-immunotherapy, using beta emitters isotopes as the 131iodine or the90yttrium, is today current in anti cancerous therapy, it finds limits because of the disintegration characteristics of the isotopes it uses. Indeed, compared with alpha particles, the beta particles deposit less energy by unit of length in the crossed material.The experimental part of this report aims at studying the feasibility of the coupling between an immunological vector and an alpha emitter isotope.The different tests led on the bismuth 213, the bismuth 212, the lead 212 and the astatine 211 demonstrated that the fixation of these radionuclides was possible. This research theme is strengthened by the construction in Nantes of a cyclotron with high energy ( A.R.R.O.N.A.X.) and the optimization of the obtained promising results should allow a therapeutic use in oncology of the alpha radio-immunotherapy. (N.C.)

  6. Suppression of scattering for small dielectric particles: an anapole mode and invisibility

    CERN Document Server

    Luk`yanchuk, Boris; Kuznetsov, Arseniy I; Miroshnichenko, Andrey E; Kivshar, Yuri S

    2016-01-01

    We reveal that an isotropic homogeneous subwavelength particle with a high refractive index can produce ultra-weak total scattering due to vanishing contribution of the electric dipole moment. This effect can be explained with the help of the Fano resonance and scattering efficiency associated with the excitation of an anapole mode. The latter is a nonradiative mode emerging from destructive interference of electric and toroidal dipole moments, and it can be employed for a design of highly transparent optical materials.

  7. Charge-exchange limits on low-energy alpha-particle fluxes in solar flares

    CERN Document Server

    Hudson, Hugh; MacKinnon, Alec; Woods, Tom

    2014-01-01

    This paper reports on a search for flare emission via charge-exchange radiation in the wings of the Lyman-alpha line of He ii at 304 A, as originally suggested for hydrogen by Orrall and Zirker. Via this mechanism a primary alpha particle that penetrates into the neutral chromosphere can pick up an atomic electron and emit in the He ii bound-bound spectrum before it stops. The Extreme-ultraviolet Variability Experiment (EVE) on board the Solar Dynamics Observatory (SDO) gives us our first chance to search for this effect systematically. The Orrall-Zirker mechanism has great importance for flare physics because of the essential roles that particle acceleration plays; this mechanism is one of the few proposed that would allow remote sensing of primary accelerated particles below a few MeV/nucleon. We study ten events in total, including the gamma-ray events SOL2010-06-12 (M2.0) and SOL2011-02-24 (M3.5) (the latter a limb flare), seven X-class flares, and one prominent M-class event that produced solar energetic...

  8. Importance of light scattering properties of cloud particles on calculating the earth energy cycle

    Science.gov (United States)

    Letu, H.; Nakajima, T. Y.; Nagao, T. M.; Ishimoto, H.

    2013-12-01

    The Earth is an open system, and the energy cycle of the Earth is not always a certain amount. In other words, the energy cycle in the nature is imbalance. A better understanding of the earth energy cycle is very important to study global climate change. the IPCC-AR4 reported that the cloud in the atmosphere are still characterized by large uncertainties in the estimation of their effects on energy sysle of the Earth's atmosphere. There are two types of cloud in the atmosphere, which are Cirrus and warm water cloud. In order to strongly reflect visible wavelength from sun light, thick water cloud has the effect of cooling the earth surface. When Cirrus is compared to water cloud, temperature is almost lower. Thus, there is a feature that Cirrus is easy to absorb long-wave radiation than warm water cloud. However, in order to quantitatively evaluate the reflection and absorption characteristics of cloud on remote senssing application and energy cycle of the imbalance of nature, it is necessary to obtain the scattering properties of cloud particles. Since the shapes of the water cloud particle are close to spherical, scattering properties of the particles can be calculated accurately by the Mie theory. However, Cirrus particles have a complex shape, including hexagonal, plate, and other non- spherical shapes. Different from warm water cloud partical, it is required to use several different light scattering methods when calculating the light scattering properties of the non-spherical Cirrus cloud particals. Ishimoto et al. [2010, 2012] and Masuda et al. [2012] developed the Finite-Difference Time Domain method (FDTD) and Improved Geometrical-Optics Method (IGOM) for the solution of light scattering by non-spherical particles. Nakajima et al [1997,2009] developed the LIght Scattering solver for Arbitral Shape particle (Lisas)-Geometrical-Optics Method (GOM) and Surface Integral Equations Method of Müller-type (SIEMM) to calculate the light scattering properties for

  9. Preface: Electromagnetic and Light Scattering by Nonspherical Particles XIV

    Science.gov (United States)

    Dubovik, Oleg; Labonnete, Laurent; Litvinov, Pavel; Parol, Frederic; Mischenko, Michael

    2014-01-01

    The 14th Electromagnetic and Light Scattering Conference (ELS-XIV) was held at the Universit de Lille 1, Villeneuve d'Ascq, France on 17-21 June 2013. The conference was attended by 200 scientists from 26 countries. The scientific program included one plenary lecture, 12 invited reviews, 100 contributed oral talks, and 86 poster presentations. The program, the abstracts, and the slides of the oral presentations are available at the conference web site http:www-loa.univ-lille1.frELS-XIV. To highlight one of the traditional ELS themes, the ELS-XIV featured a special session on Remote sensing of aerosols and clouds using polarimetric observations. This session was sponsored and co-organized by the French space agency CNES and attracted representatives from nearly all research teams word-wide involved in the development and active use of space-borne, in situ, and ground-based polarimetric observations.

  10. On classical and quantum effects at scattering of fast charged particles in ultrathin crystal

    CERN Document Server

    Shul'ga, S N; Barsuk, S; Chaikovska, I; Chehab, R

    2015-01-01

    Classical and quantum properties of scattering of charged particles in ultrathin crystals are considered. A comparison is made of these two ways of study of scattering process. In the classical consideration we remark the appearance of sharp maxima that is referred to the manifestation of the rainbow scattering phenomenon and in quantum case we show the sharp maxima that arise from the interference of single electrons on numerous crystal planes, that can be expressed in the terms of reciprocal lattice vectors. We show that for some parameters quantum predictions substantially differ from the classical ones. Estimated is the influence of the beam divergence on the possibility of experimental observation of the studied effects.

  11. Theoretical Models of Light Scattering Applied in Sizing Particles in Coal Water Slurry

    Institute of Scientific and Technical Information of China (English)

    王仁哲; 张荣曾; 徐志强

    2004-01-01

    Advantges and disadvantage of Mie scattering model and Fraunhofer diffraction model are discussed. The result shows that 1) the Fraunhofer diffraction model is simple in design and fast in operation, which is quite suitable for on-line control and 2) the intensity and energy distribution of diffracted light of both the Mie scattering model and the Fraunhofer theoretical model are compared and researched. Feasibility of using the Fraunhofer diffraction model to replace the Mie scattering model in measuring particles in coal water slurry is demonstrated.

  12. Angle-Suppressed Scattering and Optical Forces on Submicron Dielectric Particles

    CERN Document Server

    Nieto-Vesperinas, M; Saenz, J J

    2012-01-01

    We show that submicron Silicon spheres, whose polarizabilities are completely given by their two ?rst Mie coe?cients, are an excellent laboratory to test e?ects of both angle-suppressed and resonant di?erential scattering cross sections. Speci?cally, outstanding scattering angular distributions, with zero forward or backward scattered intensity, (i.e., the so-called Kerker's conditions), previously discussed for hypothetical magnetodielectric particles, are now observed for those Si objects in the near infrared. Interesting new consequences for the corresponding optical forces are derived from the interplay, both in and out resonance, between the electric and magnetic induced dipoles.

  13. Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary

    International Nuclear Information System (INIS)

    The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands during the period when this form of therapy was given for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The dose rate was approximately 100 rads/min for all cases. Fractionation varied but it is known for all cases

  14. Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary

    International Nuclear Information System (INIS)

    The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The estimated doses to the third, fourth, fifth, and sixth cranial nerves was calculated at a saggital plane 13 to 15 mm from the pituitary by using computer-drawn dosimetry charts for the respective aperture size

  15. Selection of filter media used for monitoring airborne alpha-emitting particles in a radiological emergency

    International Nuclear Information System (INIS)

    We have developed on air monitor for alpha-emitting particles released to the atmosphere at an accident of nuclear reprocessing plant. Selection of a suitable filter for the monitor is considerably important in order to achieve the high-sensitive measurement of radioactive concentration. We have examined surface collection efficiencies and pressure drops for the various filters that are commercially available in Japan. It was found that the PTFE membrane filter with backing had superior performance to the others, that is, a high surface collection efficiency and low pressure drop. (author)

  16. Theoretical and empirical status of the two-deuteron-alpha-particle vertex

    International Nuclear Information System (INIS)

    The two-deuteron-alpha-particle overlap, including its D-wave component, is evaluated in the case of realistic two- and four-body wavefunctions. The deduced theoretical value is compared with improved empirical estimates based upon DWBA analyses of (d,α) reactions in the sd shell and which incorporate the best available shell-model information for the nuclear states involved. The theoretical and empirical values of this analysis are in agreement. The result differs substantially from other recent empirical estimates obtained from (d,α) reactions upon heavier target nuclei and from simple theoretical estimates which make use of a point-deuteron approximation. (author)

  17. Mapping alpha-Particle X-Ray Fluorescence Spectrometer (Map-X)

    Science.gov (United States)

    Blake, D. F.; Sarrazin, P.; Bristow, T.

    2014-01-01

    Many planetary surface processes (like physical and chemical weathering, water activity, diagenesis, low-temperature or impact metamorphism, and biogenic activity) leave traces of their actions as features in the size range 10s to 100s of micron. The Mapping alpha-particle X-ray Spectrometer ("Map-X") is intended to provide chemical imaging at 2 orders of magnitude higher spatial resolution than previously flown instruments, yielding elemental chemistry at or below the scale length where many relict physical, chemical, and biological features can be imaged and interpreted in ancient rocks.

  18. Influence of catechins on bystander responses in CHO cells induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Law, Y.L.; Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, we studied alpha-particle induced and medium-mediated bystander effects in Chinese hamster ovary (CHO) cells through micronucleus (MN) assay. We showed that signal transduction from irradiated cells to bystander cells occur within a short time after irradiation. We then studied the effects of ROS (reactive oxygen species)-scavenging catechins in the medium before irradiation. We observed decreases in the percentage of bystander cells with MN formation and thus proved the protection effect of catechins on bystander cells from radiation.

  19. Chemistry of Rocks and Soils in Gusev Crater from the Alpha Particle X-ray Spectrometer

    Science.gov (United States)

    Gellert, R.; Rieder, R.; Anderson, R. C.; Brueckner, J.; Clark, B. C.; Dreibus, G.; Economou, T.; Klingelhoefer, G.; Lugmair, G. W.; Ming, D. W.

    2005-01-01

    The alpha particle x-ray spectrometer on the Spirit rover determined major and minor elements of soils and rocks in Gusev crater in order to unravel the crustal evolution of planet Mars. The composition of soils is similar to those at previous landing sites, as a result of global mixing and distribution by dust storms. Rocks (fresh surfaces exposed by the rock abrasion tool) resemble volcanic rocks of primitive basaltic composition with low intrinsic potassium contents. High abundance of bromine (up to 170 parts per million) in rocks may indicate the alteration of surfaces formed during a past period of aqueous activity in Gusev crater.

  20. Deuteron-and alpha particle-induced K-shell ionisation of W and Au atoms

    International Nuclear Information System (INIS)

    Deuteron - and alpha particle - induced K-shell ionisation cross sections for W and Au were obtained from thick-target measurements for low impact velocities. They were compared to proton-induced cross sections in the same range of velocities. Equal-velocity cross sections ratios are a very stringent test to the corrections incorporated to the PWBA calculations. The σd/σp data presented in this paper sheds some light on the Coulomb-deflection corrections discussed in the literature. The consequences of the inelastic character of the ionisation process are thoroughly examined. (Author)

  1. Sensitivity of alpha-particle-driven Alfven eigenmodes to q-profile variation in ITER scenarios

    CERN Document Server

    Rodrigues, P; Fazendeiro, L; Ferreira, J; Coelho, R; Nabais, F; Borba, D; Polevoi, N F Loureiro A R; Pinches, S D; Sharapov, S E

    2016-01-01

    An hybrid ideal-MHD/drift-kinetic approach to assess the stability of alpha-particle-driven Alfven eigenmodes in burning plasmas is used to show that certain foreseen ITER scenarios, namely the $I_\\mathrm{p} = 15$ MA baseline scenario with very low and broad core magnetic shear, are sensitive to small changes in the background magnetic equilibrium. Slight perturbations (of the order of 1%) in the total plasma current are seen to cause large variations in the growth rate, toroidal mode number, and radial location of the most unstable eigenmodes found. The observed sensitivity is shown to proceed from the very low magnetic shear values attained throughout the plasma core.

  2. Stratospheric aerosol particle size information in Odin-OSIRIS limb scatter spectra

    Science.gov (United States)

    Rieger, L. A.; Bourassa, A. E.; Degenstein, D. A.

    2014-02-01

    The Optical Spectrograph and InfraRed Imaging System (OSIRIS) onboard the Odin satellite has now taken over a decade of limb scatter measurements that have been used to retrieve the version 5 stratospheric aerosol extinction product. This product is retrieved using a representative particle size distribution to calculate scattering cross sections and scattering phase functions for the forward model calculations. In this work the information content of OSIRIS measurements with respect to stratospheric aerosol is systematically examined for the purpose of retrieving particle size information along with the extinction coefficient. The benefit of using measurements at different wavelengths and scattering angles in the retrieval is studied, and it is found that incorporation of the 1530 nm radiance measurement is key for a robust retrieval of particle size information. It is also found that using OSIRIS measurements at the different solar geometries available on the Odin orbit simultaneously provides little additional benefit. Based on these results, an improved aerosol retrieval algorithm is developed that couples the retrieval of aerosol extinction and mode radius of a log-normal particle size distribution. Comparison of these results with coincident measurements from SAGE III shows agreement in retrieved extinction to within approximately 10% over the bulk of the aerosol layer, which is comparable to version 5. The retrieved particle size, when converted to Ångström coefficient, shows good qualitative agreement with SAGE II measurements made at somewhat shorter wavelengths.

  3. Scattering of particles by deformed non-rotating black holes

    International Nuclear Information System (INIS)

    We study the excitation of axial quasi-normal modes of deformed non-rotating black holes by test particles and we compare the associated gravitational wave signal with that expected in general relativity from a Schwarzschild black hole. Deviations from standard predictions are quantified by an effective deformation parameter, which takes into account deviations from both the Schwarzschild metric and the Einstein equations. We show that, at least in the case of non-rotating black holes, it is possible to test the metric around the compact object, in the sense that the measurement of the gravitational wave spectrum can constrain possible deviations from the Schwarzschild solution

  4. Scattering of particles by deformed non-rotating black holes

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Guancheng [Department of Physics, Center for Field Theory and Particle Physics, Fudan University, 200433, Shanghai (China); Bambi, Cosimo, E-mail: bambi@fudan.edu.cn [Department of Physics, Center for Field Theory and Particle Physics, Fudan University, 200433, Shanghai (China); Theoretical Astrophysics, Eberhard-Karls Universität Tübingen, 72076, Tübingen (Germany)

    2015-11-27

    We study the excitation of axial quasi-normal modes of deformed non-rotating black holes by test particles and we compare the associated gravitational wave signal with that expected in general relativity from a Schwarzschild black hole. Deviations from standard predictions are quantified by an effective deformation parameter, which takes into account deviations from both the Schwarzschild metric and the Einstein equations. We show that, at least in the case of non-rotating black holes, it is possible to test the metric around the compact object, in the sense that the measurement of the gravitational wave spectrum can constrain possible deviations from the Schwarzschild solution.

  5. Scattering of particles by deformed non-rotating black holes

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Guancheng [Fudan University, Department of Physics, Center for Field Theory and Particle Physics, Shanghai (China); Bambi, Cosimo [Fudan University, Department of Physics, Center for Field Theory and Particle Physics, Shanghai (China); Eberhard-Karls Universitaet Tuebingen, Theoretical Astrophysics, Tuebingen (Germany)

    2015-11-15

    We study the excitation of axial quasi-normal modes of deformed non-rotating black holes by test particles and we compare the associated gravitational wave signal with that expected in general relativity from a Schwarzschild black hole. Deviations from standard predictions are quantified by an effective deformation parameter, which takes into account deviations from both the Schwarzschild metric and the Einstein equations. We show that, at least in the case of non-rotating black holes, it is possible to test the metric around the compact object, in the sense that the measurement of the gravitational wave spectrum can constrain possible deviations from the Schwarzschild solution. (orig.)

  6. The fine structure constant alpha: relevant for a model of a self-propelling photon and for particle masses

    Science.gov (United States)

    Greulich, Karl O.

    2015-09-01

    A model for a self propelling (i.e. massless) photon1 is based on oscillations of a pair of charges amounting to elementary charge divided by SQRT alpha, where alpha is the fine structure (Sommerfeld) constant. When one assumes a similar model for particles that do have rest mas (i.e. which are non- self propelling), alpha plays also a role in the rest masses of elementary particles. Indeed all fundamental elementary particle masses can be described by the alpha / beta rule2 --> m(particle) = alpha-n * betam* 27.2 eV /c2 where beta is the proton to electron mass ratio 183612 and n= 0….14, m= -1,0 or Thus, photons and particle masses are intimately related to the fine structure constant. If the latter would not have been strictly constant throughout all times, this would have had consequences for the nature of light and for all masses including those of elementary particles.

  7. Particle-scale structure in frozen colloidal suspensions from small-angle x-ray scattering

    KAUST Repository

    Spannuth, Melissa

    2011-02-01

    During directional solidification of the solvent in a colloidal suspension, the colloidal particles segregate from the growing solid, forming high-particle-density regions with structure on a hierarchy of length scales ranging from that of the particle-scale packing to the large-scale spacing between these regions. Previous work has concentrated mostly on the medium- to large-length scale structure, as it is the most accessible and thought to be more technologically relevant. However, the packing of the colloids at the particle scale is an important component not only in theoretical descriptions of the segregation process, but also to the utility of freeze-cast materials for new applications. Here we present the results of experiments in which we investigated this structure across a wide range of length scales using a combination of small-angle x-ray scattering and direct optical imaging. As expected, during freezing the particles were concentrated into regions between ice dendrites forming a microscopic pattern of high- and low-particle-density regions. X-ray scattering indicates that the particles in the high-density regions were so closely packed as to be touching. However, the arrangement of the particles does not conform to that predicted by standard interparticle pair potentials, suggesting that the particle packing induced by freezing differs from that formed during equilibrium densification processes. © 2011 American Physical Society.

  8. Scattering from Model Nonspherical Particles Theory and Applications to Environmental Physics

    CERN Document Server

    Borghese, Ferdinando; Saija, Rosalba

    2007-01-01

    The scattering of electromagnetic radiation by nonspherical particles has become an increasingly important research topic over the past 20 years. Instead of handling anisotropic particles of arbitrary shape, the authors consider the more amenable problem of aggregates of spherical particles. This is often a very satisfactory approach as the optical response of nonspherical particles depends more on their general symmetry and the quantity of refractive material than on the precise details of their shape. The book addresses a wide spectrum of applications, ranging from scattering properties of water droplets containing pollutants, atmospheric aerosols and ice crystals to the modeling of cosmic dust grains as aggregates. In this extended second edition the authors have encompassed all the new topics arising from their recent studies of cosmic dust grains. Thus many chapters were deeply revised and new chapters were added. The new material spans The description of the state of polarization of electromagnetic wave...

  9. Scattering properties of the interplanetary medium obtained from angular distribution of solar energetic particles

    International Nuclear Information System (INIS)

    Solar energetic particles can be used as probes for the turbulence level in the interplanetary medium. We discuss various methods by which the scattering conditions can be determined, (a) overall fits of observed particle intensities and anisotropies to a transport model, (b) evaluation of the steady-state pitch angle distribution, (c) suitably normalized angular distributions during the intensity maximum of a particle event. Results from solar particle events observed on HELIOS 1 and 2 show that the global mean free paths determined by usage of methods (a) and (b) agree well with each other. Large variations in the degree of scattering exist from one event to the other. The assumption λr(r)=const underlying the derivation of a global mean free path will have to be modified

  10. Classification of single particle optical scattering patterns by the spectrum enhancement algorithm (contributed talk)

    OpenAIRE

    Crosta, GF

    2005-01-01

    Some experimental methods such as TAOS [S. Holler et al., Appl. Optics 43 (33) (2004) 6198-6206] are capable of collecting the light scattered by single airborne particles in the micrometer size range when the latter are illuminated by a triggered LASER source. Data consist of intensity patterns collected in a suitable solid angle and made available at a high rate (\\>100 patterns per second). There is no known theoretical method capable of determining the particle size, shape and complex refr...

  11. Momentum correlations of scattered particles in quantum field theory: one-loop entanglement generation

    CERN Document Server

    Faleiro, Ricardo; Alexander, Helder; Hiller, Brigitte; Blin, Alex; Sampaio, Marcos

    2016-01-01

    We compute the entanglement entropy variation between initial (separable or entangled in the momenta) and final states $\\Delta S_E$ in an elastic scattering of a bipartite system composed by two interacting scalar particles. We perform a quantum field theoretical calculation to one loop order and verify that $\\Delta S_E $ changes as we vary the energy of incoming particles and the coupling strength in a non-trivial way.

  12. Physical consequences of the alpha/beta rule which accurately calculates particle masses

    International Nuclear Information System (INIS)

    Using the fine structure constant α (=1/137.036), the proton vs. electron mass ratio β (= 1836.2) and the integers m and n, the α/β rule: mparticle = α-n x β m x 27.2 eV/c2 allows almost exact calculation of particle masses. (K.O.Greulich, DPG Spring meeting 2014, Mainz, T99.4) With n=2, m=0 the electron mass becomes 510.79 keV/c2 (experimental 511 keV/c2) With n=2, m=1 the proton mass is 937.9 MeV/c2 (literature 938.3 MeV/c2). For n=3 and m=1 a particle with 128.6 GeV/c2 close to the reported Higgs mass, is expected. For n=14 and m=-1 the Planck mass results. The calculated masses for gauge bosons and for quarks have similar accuracy. All masses fit into the same scheme (the alpha/beta rule), indicating that non of these particle masses play an extraordinary role. Particularly, the Higgs Boson, often termed the *God particle* plays in this sense no extraordinary role. In addition, particle masses are intimately correlated with the fine structure constant α. If particle masses have been constant over all times, α must have been constant over these times. In addition, the ionization energy of the hydrogen atom (13.6 eV) needs to have been constant if particle masses have been unchanged or vice versa. In conclusion, the α/β rule needs to be taken into account when cosmological models are developed.

  13. Inclusive jet cross sections in the Breit frame in neutral current deep inelastic scattering at HERA and determination of $\\alpha_{s}$

    CERN Document Server

    Chekanov, S; Adamczyk, L; Adamus, M; Adler, V; Aghuzumtsyan, G; Allfrey, P D; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P M; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Büttner, C; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cassel, D G; Catterall, C D; Abramowicz, H; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danilov, P; De Pasquale, S; Dementiev, R K; Derrick, M; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Everett, A; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Graciani-Díaz, R; Grigorescu, G; Grijpink, S; Groys, M; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Hilger, E; Hochman, D; Holm, U; Horn, C; Iacobucci, G; Iga, Y; Irrgang, P; Jakob, H P; Jiménez, M; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karshon, U; Karstens, F; Kasemann, M; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowalski, H; Kramberger, G; Kreisel, A; Krumnack, N; Kulinski, P; Kuze, M; Kuzmin, V A; Labarga, L; Lammers, S; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Limentani, S; Ling, T Y; Liu, C; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Ma, K J; Maddox, E; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Martínez, M; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Olkiewicz, K; Ota, O; Padhi, S; Palmonari, F; Patel, S; Paul, E; Pavel, Usan; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plamondon, M; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Robins, S; Rosin, M; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Santamarta, R; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Tyszkiewicz, A; Ukleja, A; Ukleja, J; Vázquez, M; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Whitmore, J J; Whyte, J; Wichmann, K; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wlasenko, M; Wolf, G; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Ziegler, A; Zotkin, D S; Zotkin, S A; De Favereau, J; De Wolf, E; Del Peso, J

    2002-01-01

    Inclusive jet differential cross sections have been measured in neutral current deep inelastic e+p scattering for boson virtualities Q**2>125 GeV**2. The data were taken using the ZEUS detector at HERA and correspond to an integrated luminosity of 38.6 pb-1. Jets were identified in the Breit frame using the longitudinally invariant K_T cluster algorithm. Measurements of differential inclusive jet cross sections are presented as functions of jet transverse energy (E_T,jet), jet pseudorapidity and Q**2, for jets with E_T,jet>8 GeV. Next-to-leading-order QCD calculations agree well with the measurements both at high Q**2 and high E_T,jet. The value of alpha_s(M_Z), determined from an analysis of dsigma/dQ**2 for Q**2>500 GeV**2, is alpha_s(M_Z) = 0.1212 +/- 0.0017 (stat.) +0.0023 / -0.0031 (syst.) +0.0028 / -0.0027 (th.).

  14. Dual-wavelength light scattering for selective detection of volcanic ash particles

    Science.gov (United States)

    Jurányi, Z.; Burtscher, H.; Loepfe, M.; Nenkov, M.; Weingartner, E.

    2015-08-01

    A new method is presented in this paper which analyses the scattered light of individual aerosol particles simultaneously at two different wavelengths in order to retrieve information on the particle type. We show that dust-like particles, such as volcanic ash, can be unambiguously discriminated from water droplets on a single particle level. As a future application of this method, the detection of volcanic ash particles should be possible in a humid atmosphere in the presence of cloud droplets. We show an example, how the characteristic behaviour of pure water's refractive index can be used to separate water droplets and dust-like particles which are commonly found in the micrometer size-range in the ambient air. The low real part of the water's refractive index around 2700-2800 nm results in low scattered light intensities compared to e.g. the visible wavelength range and this feature can be used for the particle identification. The two-wavelength measurement setup was theoretically and experimentally tested and studied. Theoretical calculations were done using Mie theory. Comparing the ratio of the scattered light at the two wavelengths (R value) for water droplets and different dust types (basalt, andesite, African mineral dust, sand, volcanic ash, pumice) showed at least 9 times higher values (on average 70 times) for water droplets than for the dust types at any diameter within the particle size range of 2-20 μm. The envisaged measurement setup was built up into a laboratory prototype and was tested with different types of aerosols. We generated aerosols from the following powders simulating dust-like particles: cement dust, ISO 12103-1 A1 Ultrafine Test Dust and Ash from the 2012 eruption of the Etna volcano. Our measurements verified the theoretical considerations, the median experimental R value is 8-21 times higher for water than for the "dust" particles.

  15. Dual-wavelength light scattering for selective detection of volcanic ash particles

    Directory of Open Access Journals (Sweden)

    Z. Jurányi

    2015-08-01

    Full Text Available A new method is presented in this paper which analyses the scattered light of individual aerosol particles simultaneously at two different wavelengths in order to retrieve information on the particle type. We show that dust-like particles, such as volcanic ash, can be unambiguously discriminated from water droplets on a single particle level. As a future application of this method, the detection of volcanic ash particles should be possible in a humid atmosphere in the presence of cloud droplets. We show an example, how the characteristic behaviour of pure water's refractive index can be used to separate water droplets and dust-like particles which are commonly found in the micrometer size-range in the ambient air. The low real part of the water's refractive index around 2700–2800 nm results in low scattered light intensities compared to e.g. the visible wavelength range and this feature can be used for the particle identification. The two-wavelength measurement setup was theoretically and experimentally tested and studied. Theoretical calculations were done using Mie theory. Comparing the ratio of the scattered light at the two wavelengths (R value for water droplets and different dust types (basalt, andesite, African mineral dust, sand, volcanic ash, pumice showed at least 9 times higher values (on average 70 times for water droplets than for the dust types at any diameter within the particle size range of 2–20 μm. The envisaged measurement setup was built up into a laboratory prototype and was tested with different types of aerosols. We generated aerosols from the following powders simulating dust-like particles: cement dust, ISO 12103-1 A1 Ultrafine Test Dust and Ash from the 2012 eruption of the Etna volcano. Our measurements verified the theoretical considerations, the median experimental R value is 8–21 times higher for water than for the "dust" particles.

  16. Investigation of the performance of alpha particle counting and alpha-gamma discrimination by pulse shape with micro-pixel avalanche photodiode

    International Nuclear Information System (INIS)

    Being capable measuring small lights gives possibility to use micro-pixel avalanche photodiodes with scintillators. It is shown two prototypes to use micro-pixel avalanche photodiodes with and without scintillators as alpha and gamma counters in this paper. First prototype is to use two micro-pixel avalanche photodiodes. One for detecting alpha particles and closer to it, the second one with a thin plastic scintillator for detecting gamma rays. Second prototype is called two-layers configuration in which it is used only one micro-pixel avalanche photodiode, but two scntillators with different decay times. One can distinquish alpha particle and gamma ray events by using pulse shape discrimination techniques in the two-layer configuration. In this work an alpha particle and gamma ray counting performance of micro-pixel avalanche photodiodes without scintillators and its combination of plastic and BGO+ plastic scintillators was investigated. Obtained results showed the detection performance of the micro-pixel avalanche photodiodes in combination with plastic scintillator was about the same as conventional semiconductor detectors

  17. Etching characteristic studies for the detection of alpha particles in DAM–ADC nuclear track detector

    International Nuclear Information System (INIS)

    This study reports the characteristic studies for the detection of alpha particles in DAM–ADC nuclear track detector. Several important parameters that control the track formation such as, the bulk etch rate (VB), track etching rate (VT), dependence of VB and VT on etching concentration and temperature have been extensively studied. The activation energy (Eb) of the bulk etching rate for the DAM–ADC sheets has been calculated, the dependence of etching efficiency and sensitivity upon etchant concentrations and temperature has been investigated, registration efficiency of DAM–ADC detector etched at the optimum etching condition has been examined. The detailed studied results presented in this study provide various useful information about the mechanism of track formation in polymers. - Highlights: • Detection of alpha particles in DAM–ADC nuclear track detector. • The activation energy of the bulk etching rate for the DAM–ADC sheets. • The dependence of etching efficiency upon etchant concentrations • Registration efficiency of DAM–ADC detector

  18. An improved electrostatic integrating radon monitor with the CR-39 as alpha-particle detector

    International Nuclear Information System (INIS)

    In this study, based on the electrostatic integrating radon monitor (EIRM) developed by Iida et al., a new type of EIRM with the allyl glycol carbonate (CR-39) as alpha-particle detector was developed for outdoor radon measurements. Besides using the CR-39 to replace the cellulose nitrate film as alpha-particle detector, the electrode and the setting place of the CR-39 were also optimally designed based on the simulation results of the electric field and the detection efficiency. The calibration factor of the new EIRM was estimated to be 0.136±0.002 tracks cm-2 (Bq m-3 h)-1, with the lower detection limit of 0.6 Bq m-3 for a 2-month exposure. Furthermore, both the battery and the dry agent were also replaced to protect the environment. The results of intercomparison and field experiments showed that the performances of the new EIRM were much better than the original one. It suggests that the new type of ERIM is more suitable for large-scale and long-term outdoor radon surveys. (authors)

  19. Revisiting alpha decay-based near-light-speed particle propulsion.

    Science.gov (United States)

    Zhang, Wenwu; Liu, Zhen; Yang, Yang; Du, Shiyu

    2016-08-01

    Interplanet and interstellar travels require long-term propulsion of spacecrafts, whereas the conventional schemes of propulsion are limited by the velocity of the ejected mass. In this study, alpha particles released by nuclear decay are considered as a potential solution for long-time acceleration. The principle of near-light-speed particle propulsion (NcPP) was elucidated and the stopping and range of ions in matter (SRIM) was used to predict theoretical accelerations. The results show that NcPP by means of alpha decay is feasible for long-term spacecraft propulsion and posture adjustment in space. A practical NcPP sail can achieve a speed >150km/s and reach the brink of the solar system faster than a mass equivalent solar sail. Finally, to significantly improve the NcPP sail, the hypothesis of stimulated acceleration of nuclear decay (SAND) was proposed, which may shorten the travel time to Mars to within 20 days. PMID:27161512

  20. Project and construction of a spectrometer for alpha particles using surface barrier detectors

    International Nuclear Information System (INIS)

    The project, construction, tests and some applications of a system for alpha and beta spectrometry, using surface barrier detector are described. The device includes a solid state detector ORTEC-Series F coupled to a system for amplifying the charges produced by passage of an ionizing particle through the detector. The amplifying system is composed by a charge sensitive pre-amplifier, which employs an operational amplifier CA 3140, and a low noise linear amplifier, which is based on the operational amplifiers CA 3140 and LM 301. The pre-amplifier stage input impedance is on the order of TΩ and produces output pulses which heights are proportional to total charge produced by passage of particle through the detector sensitive volume. The main advantage to use charge sensitive system lies in obtention of independent pulse heights of the distributed capacity of connecting cable between the detector and the pre-amplifier. The total system amplification ca reach a maximum of 50.000 in the linear region. Pulses are analysed in a multichannel system ORTEC, model 6240. The amplifier system is easily constructed and low cost using components available in the national market, and it can be employed with ionization chambers, proportional counters, scitillation counters and semiconductor detectors. The results of spectrometer application for alpha spectrometry of AM241 source were compared to systems made with imported stages. (Author)

  1. Development of scintillator plates with high energy resolution for alpha particles made of GPS scintillator grains

    International Nuclear Information System (INIS)

    A scintillator plate with high energy resolution was developed to produce an alpha particle monitor used in nuclear fuel reprocessing plants and mixed plutonium-uranium oxide (MOX) fuel plants. Grains of a Gd2Si2O7 (GPS) scintillator of several 10 to 550 μm were fixed on a glass substrate and were then mechanically polished. By increasing the size of scintillator grains and removing fine powders, the collected light yield and energy resolution for alpha particles were drastically improved. Energy resolution of 9.3% was achieved using average grain size of 91 μm. Furthermore, the ratios between counts in a peak and total counts were improved by more than 60% by the further increase of grain size and adoption of mechanically polished surfaces on both sides. Beta and gamma ray influences were suppressed sufficiently by the thin 100 μm scintillator plates. -- Highlights: • A scintillator plate was fabricated using Gd2Si2O7 grains of several 10 to 550 μm. • Scintillator grains were fixed on a glass substrate and were mechanically polished. • Energy resolution of 9.3% was achieved using average grains size of 91 μm. • This technique has no limitation in area size. • Radiation background was eliminated by thin thickness of scintillator, i.e. 100 μm

  2. Activation cross sections of longer-lived radionuclides produced in germanium by alpha particle irradiation

    Science.gov (United States)

    Takács, S.; Takács, M. P.; Ditrói, F.; Aikawa, M.; Haba, H.; Komori, Y.

    2016-09-01

    The cross sections of alpha particles induced nuclear reactions on natural germanium were investigated by using the standard stacked foil target technique, the activation method and high resolution gamma spectrometry. Targets with thickness of about 1 μm were prepared from natural Ge by vacuum evaporation onto 25 μm thick polyimide (Kapton) backing foils. Stacks were composed of Kapton-Ge-Ge-Kapton sandwich target foils and additional titanium monitor foils with nominal thickness of 11 μm to monitor the beam parameters using the natTi(α,x)51Cr reaction. The irradiations were done with Eα = 20.7 and Eα = 51.25 MeV, Iα = 50 nA alpha particle beams for about 1 h. Direct or cumulative activation cross sections were determined for production of the 72,73,75Se, 71,72,74,76,78As, and 69Ge radionuclides. The obtained experimental cross sections were compared to the results of theoretical calculations taken from the TENDL data library based on the TALYS computer code. A comparison was made with available experimental data measured earlier. Thick target yields were deduced from the experimental cross sections and compared with the data published before.

  3. Targeted Cytoplasmic Irradiation with Alpha Particles Induces Mutations in Mammalian Cells

    Science.gov (United States)

    Wu, Li-Jun; Randers-Pehrson, Gerhard; Xu, An; Waldren, Charles A.; Geard, Charles R.; Yu, Zengliang; Hei, Tom K.

    1999-04-01

    Ever since x-rays were shown to induce mutation in Drosophila more than 70 years ago, prevailing dogma considered the genotoxic effects of ionizing radiation, such as mutations and carcinogenesis, as being due mostly to direct damage to the nucleus. Although there was indication that alpha particle traversal through cellular cytoplasm was innocuous, the full impact remained unknown. The availability of the microbeam at the Radiological Research Accelerator Facility of Columbia University made it possible to target and irradiate the cytoplasm of individual cells in a highly localized spatial region. By using dual fluorochrome dyes (Hoechst and Nile Red) to locate nucleus and cellular cytoplasm, respectively, thereby avoiding inadvertent traversal of nuclei, we show here that cytoplasmic irradiation is mutagenic at the CD59 (S1) locus of human-hamster hybrid (AL) cells, while inflicting minimal cytotoxicity. The principal class of mutations induced are similar to those of spontaneous origin and are entirely different from those of nuclear irradiation. Furthermore, experiments with radical scavenger and inhibitor of intracellular glutathione indicated that the mutagenicity of cytoplasmic irradiation depends on generation of reactive oxygen species. These findings suggest that cytoplasm is an important target for genotoxic effects of ionizing radiation, particularly radon, the second leading cause of lung cancer in the United States. In addition, cytoplasmic traversal by alpha particles may be more dangerous than nuclear traversal, because the mutagenicity is accomplished by little or no killing of the target cells.

  4. Scattering of massless particles: scalars, gluons and gravitons

    Science.gov (United States)

    Cachazo, Freddy; He, Song; Yuan, Ellis Ye

    2014-07-01

    In a recent note we presented a compact formula for the complete tree-level S-matrix of pure Yang-Mills and gravity theories in arbitrary spacetime dimension. In this paper we show that a natural formulation also exists for a massless colored cubic scalar theory. In Yang-Mills, the formula is an integral over the space of n marked points on a sphere and has as integrand two factors. The first factor is a combination of Parke-Taylor-like terms dressed with U( N ) color structures while the second is a Pfaffian. The S-matrix of a U( N ) × U( Ñ ) cubic scalar theory is obtained by simply replacing the Pfaffian with a U( Ñ ) version of the previous U( N ) factor. Given that gravity amplitudes are obtained by replacing the U( N ) factor in Yang-Mills by a second Pfaffian, we are led to a natural color-kinematics correspondence. An expansion of the integrand of the scalar theory leads to sums over trivalent graphs and are directly related to the KLT matrix. Combining this and the Yang-Mills formula we find a connection to the BCJ color-kinematics duality as well as a new proof of the BCJ doubling property that gives rise to gravity amplitudes. We end by considering a special kinematic point where the partial amplitude simply counts the number of color-ordered planar trivalent trees, which equals a Catalan number. The scattering equations simplify dramatically and are equivalent to a special Y-system with solutions related to roots of Chebyshev polynomials. The sum of the integrand over the solutions gives rise to a representation of Catalan numbers in terms of eigenvectors and eigenvalues of the adjacency matrix of an A-type Dynkin diagram.

  5. A new method for alpha-particle detection in a classroom experiment

    International Nuclear Information System (INIS)

    Complete text of publication follows. The World Year of Physics (WYP 2005) was a worldwide celebration of Physics and its importance in our everyday lives. In harmony with its aims, that is to raise the worldwide awareness of Physics and Physical Science, we introduced a novel lab work involving a new imaging and data evaluation method for alpha-particle detection, which can be easily implemented in a classroom environment. The target group of the experiments is mainly secondary school students (age between 16-18 years). Our aim is to motivate students to develop a better understanding of Physics, allowing them to experience for themselves something of its fascination. In order to increase their attractiveness, the experiments include using a CMOS video image sensor with a video output. The covering glass window of the sensor must be carefully removed in order to make it sensitive for alpha rays. The sensor is connected to a computer where the images are recorded as a short video clip. The recorded video is played back by frames. The resulted frames are then merged together into one image. On this image the student can count the number of spots, where each spot corresponds to a hit of an alpha particle. The experiment can also be visible on a TV screen even by a whole class, however the authors suggest implementing the following experiments as a practical work individually or in small groups. As students are familiar with modern information technology, we think that they will be highly motivated to make these experiments on their own. Acknowledgements. The development of the above experimental setup was funded by ATOMKI and it was presented to the interactive science centre 'Magic corner', Debrecen, Hungary at Christmas, 2005. (author)

  6. Selective alpha-particle mediated depletion of tumor vasculature with vascular normalization.

    Directory of Open Access Journals (Sweden)

    Jaspreet Singh Jaggi

    Full Text Available BACKGROUND: Abnormal regulation of angiogenesis in tumors results in the formation of vessels that are necessary for tumor growth, but compromised in structure and function. Abnormal tumor vasculature impairs oxygen and drug delivery and results in radiotherapy and chemotherapy resistance, respectively. Alpha particles are extraordinarily potent, short-ranged radiations with geometry uniquely suitable for selectively killing neovasculature. METHODOLOGY AND PRINCIPAL FINDINGS: Actinium-225 ((225Ac-E4G10, an alpha-emitting antibody construct reactive with the unengaged form of vascular endothelial cadherin, is capable of potent, selective killing of tumor neovascular endothelium and late endothelial progenitors in bone-marrow and blood. No specific normal-tissue uptake of E4G10 was seen by imaging or post-mortem biodistribution studies in mice. In a mouse-model of prostatic carcinoma, (225Ac-E4G10 treatment resulted in inhibition of tumor growth, lower serum prostate specific antigen level and markedly prolonged survival, which was further enhanced by subsequent administration of paclitaxel. Immunohistochemistry revealed lower vessel density and enhanced tumor cell apoptosis in (225Ac-E4G10 treated tumors. Additionally, the residual tumor vasculature appeared normalized as evident by enhanced pericyte coverage following (225Ac-E4G10 therapy. However, no toxicity was observed in vascularized normal organs following (225Ac-E4G10 therapy. CONCLUSIONS: The data suggest that alpha-particle immunotherapy to neovasculature, alone or in combination with sequential chemotherapy, is an effective approach to cancer therapy.

  7. Correcting for interplanetary scattering in velocity dispersion analysis of solar energetic particles

    CERN Document Server

    Laitinen, T; Valtonen, E; Dalla, S

    2015-01-01

    To understand the origin of Solar Energetic Particles (SEPs), we must study their injection time relative to other solar eruption manifestations. Traditionally the injection time is determined using the Velocity Dispersion Analysis (VDA) where a linear fit of the observed event onset times at 1 AU to the inverse velocities of SEPs is used to derive the injection time and path length of the first-arriving particles. VDA does not, however, take into account that the particles that produce a statistically observable onset at 1 AU have scattered in the interplanetary space. We use Monte Carlo test particle simulations of energetic protons to study the effect of particle scattering on the observable SEP event onset above pre-event background, and consequently on VDA results. We find that the VDA results are sensitive to the properties of the pre-event and event particle spectra as well as SEP injection and scattering parameters. In particular, a VDA-obtained path length that is close to the nominal Parker spiral l...

  8. Hazardous gas production by alpha particles in solid organic transuranic waste matrices. 1998 annual progress report

    International Nuclear Information System (INIS)

    'This project uses fundamental radiation chemical techniques to elucidate the basic processes occurring in the heavy-ion radiolysis of solid hydrocarbon matrices such as polymers and organic resins that are associated with many of the transuranic waste deposits or the transportation of these radionuclides. The environmental management of mixed waste containing transuranic radionuclides is difficult because these nuclides are alpha particle emitters and the energy deposited by the alpha particles causes chemical transformations in the matrices accompanying the waste. Most radiolysis programs focus on conventional radiation such as gamma rays, but the chemical changes induced by alpha particles and other heavy ions are typically very different and product yields can vary by more than an order of magnitude. The objective of this research is to measure the production of gases, especially molecular hydrogen, produced in the proton, helium ion, and carbon ion radiolysis of selected solid organic matrices in order to obtain fundamental mechanistic information on the radiolytic decomposition of these materials. This knowledge can also be used to directly give reasonable estimates of explosive or flammability hazards in the storage or transport of transuranic wastes in order to enhance the safety of DOE sites. This report summarizes the work after eight months of a three-year project on determining the production of hazardous gases in transuranic waste. The first stage of the project was to design and build an assembly to irradiate solid organic matrices using accelerated ion beams. It is necessary to measure absolute radiolytic yields, and simulate some of the conditions found in the field. A window assembly was constructed allowing the beam to pass consecutively through a collimator, a vacuum exit window and into the solid sample. The beam is stopped in the sample and the entire end of the assembly is a Faraday cup. Integration of the collected current, in conjunction

  9. Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2009-10-15

    Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

  10. Feasibility study on the use of polyallyldiglycol-carbonate cell dishes in TUNEL assay for alpha particle radiobiological experiments

    Science.gov (United States)

    Chan, K. F.; Yum, E. H. W.; Wan, C. K.; Fong, W. F.; Yu, K. N.

    2007-08-01

    In the present work, we have studied the feasibility of a method based on polyallyldiglycol-carbonate (PADC) films to investigate the effects of alpha particles on HeLa cervix cancer cells. Thin PADC films with thickness of about 20 μm were prepared from commercially available CR-39 films by chemical etching to fabricate custom-made petri dishes for cell culture, which could accurately record alpha particle hit positions. A special method involving "base tracks" for aligning the images of cell nuclei and alpha particle hits has been proposed, so that alpha particle transversals of cell nuclei can be visually counted. Radiobiological experiments were carried out to induce DNA damages, with the TdT-mediated d UTP Nick- End Labeling (TUNEL) fluorescence method employed to detect DNA strand breaks. The staining results were investigated by flow cytometer. The preliminary results showed that more strand breaks occurred in cells hit by alpha particles with lower energies. Moreover, large TUNEL positive signals were obtained even with small percentages of cells irradiated and TUNEL signals were also obtained from non-targeted cells. These provided evidence for the bystander effect.

  11. Feasibility study on the use of polyallyldiglycol-carbonate cell dishes in TUNEL assay for alpha particle radiobiological experiments

    Energy Technology Data Exchange (ETDEWEB)

    Chan, K.F. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Yum, E.H.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Wan, C.K. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong, Hong Kong (China); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China)]. E-mail: peter.yu@cityu.edu.hk

    2007-08-15

    In the present work, we have studied the feasibility of a method based on polyallyldiglycol-carbonate (PADC) films to investigate the effects of alpha particles on HeLa cervix cancer cells. Thin PADC films with thickness of about 20 {mu}m were prepared from commercially available CR-39 films by chemical etching to fabricate custom-made petri dishes for cell culture, which could accurately record alpha particle hit positions. A special method involving 'base tracks' for aligning the images of cell nuclei and alpha particle hits has been proposed, so that alpha particle transversals of cell nuclei can be visually counted. Radiobiological experiments were carried out to induce DNA damages, with the TdT-mediated dUTP Nick-End Labeling (TUNEL) fluorescence method employed to detect DNA strand breaks. The staining results were investigated by flow cytometer. The preliminary results showed that more strand breaks occurred in cells hit by alpha particles with lower energies. Moreover, large TUNEL positive signals were obtained even with small percentages of cells irradiated and TUNEL signals were also obtained from non-targeted cells. These provided evidence for the bystander effect.

  12. Correcting for Interplanetary Scattering in Velocity Dispersion analysis of Solar Energetic Particles

    Science.gov (United States)

    Laitinen, T.; Huttunen-Heikinmaa, K.; Valtonen, E.; Dalla, S.

    2015-06-01

    To understand the origin of Solar Energetic Particles (SEPs), we must study their injection time relative to other solar eruption manifestations. Traditionally the injection time is determined using the Velocity Dispersion Analysis (VDA) where a linear fit of the observed event onset times at 1 AU to the inverse velocities of SEPs is used to derive the injection time and path length of the first-arriving particles. VDA does not, however, take into account that the particles that produce a statistically observable onset at 1 AU have scattered in the interplanetary space. We use Monte Carlo test particle simulations of energetic protons to study the effect of particle scattering on the observable SEP event onset above pre-event background, and consequently on VDA results. We find that the VDA results are sensitive to the properties of the pre-event and event particle spectra as well as SEP injection and scattering parameters. In particular, a VDA-obtained path length that is close to the nominal Parker spiral length does not imply that the VDA injection time is correct. We study the delay to the observed onset caused by scattering of the particles and derive a simple estimate for the delay time by using the rate of intensity increase at the SEP onset as a parameter. We apply the correction to a magnetically well-connected SEP event of 2000 June 10, and show it to improve both the path length and injection time estimates, while also increasing the error limits to better reflect the inherent uncertainties of VDA.

  13. Scattering by Nonspherical Ice Particles at High Microwave Frequencies and Its Application to Snowfall Retrievals (Invited)

    Science.gov (United States)

    Liu, G.

    2010-12-01

    Despite their great significance in modulating the Earth radiation budget and the global hydrological cycle, cloud ice water and snow precipitation remain to be the most inadequately measured geophysical variables. One promising approach is to estimate the ice water amount and/or snowfall rate by measuring the scattering signatures at microwave frequencies by either active (radars) or passive radiometers) remote sensing. Satellite data from CloudSat radar and future GPM radiometers provide excellent opportunities to retrieve cloud ice water and snowfall globally. To develop an algorithm that converts the observed radar reflectivity or brightness temperature to ice water amount or snowfall rate, one must know the single-scattering properties, i.e., scattering cross sections, phase functions, etc., of the ice/snow particles. The nonspherical nature of ice particles adds one more layer of complexity to the cloud/precipitation retrieval problem that has already been complicated by the uncertainties of particle size distributions, surface contaminations, beam-filling problems, etc. The ultimate goal of this study is to find the most appropriate way in representing ice particle scattering in radar reflectivity and radiative transfer calculations. In this talk, we first review previous studies related to the scattering of nonspherical ice particles at the microwave spectrum, and demonstrate some of the advantages and pitfalls in approximating ice particles as “spheres with an assigned density” in radiative transfer and radar reflectivity calculations. Then, our current effort to build an comprehensive single-scattering database of realistic ice/snow particles by using Discrete Dipole Approximation calculations will be introduced. In particular, our effort in designing realistic “snowflakes” with many constituent ice crystals based on observed structural properties of snowflakes will be introduced. The single-scattering properties of these snowflakes and the

  14. On the Theory and Simulation of Multiple Coulomb Scattering of Heavy Charged Particles

    CERN Document Server

    Striganov, S I

    2004-01-01

    The Moliere theory of multiple Coulomb scattering is modified to take into account difference between scattering off atomic nuclei and electron. A simple analytical expression for angular distribution of charged particles passing through a thick absorber is found. It does not assume any special form for a differential cross section and has wider range of applicability than a Gaussian approximation. A well-known method to simulate multiple Coulomb scattering is based on the different treatment of soft and hard collisions. An angular deflection in a large number of soft collisions is sampled using the proposed distribution function, a small number of hard collisions are simulated directly. A boundary between hard and soft collisions is defined providing a precise sampling of scattering angle (1% level) and small number of hard collisions. A corresponding simulation module takes into account projectile and nucleus charge distributions and exact kinematics of a projectile-electron interaction.

  15. Multiple-scattering effects in proton- and alpha-nucleus reactions with Glauber theory

    International Nuclear Information System (INIS)

    We study the total reaction and elastic differential cross sections for proton-nucleus and 4He-nucleus reactions in the framework of the Glauber theory which describes multiplescattering processes. The input wave functions are obtained using the Skyrme-Hartree-Fock method and prepared for a wide range of mass numbers, O, Ca, Ni, Sn, and Pb isotopes. The theory reproduces experimental data very well. An effect of the multiple scattering is discussed by comparing with a standard optical-limit approximation. We see that the multiple-scattering effects play a crucial role, especially in enhancing the elastic differential cross sections at large scattering angles

  16. Application of extended kinetic theory to particle transport with inelastic scattering

    International Nuclear Information System (INIS)

    In the frame of extended kinetic theory, the linear Boltzmann equation for test particles in an absorbing and inelastically scattering background leads to a partial-integral-difference equation which is studied in the proper mathematical setting. As an application, penetration of a beam of particles in a plane slab is considered in steady state conditions, and the relevant problem is solved by a rigorous algorithm. Accurate results for particle and energy distributions, and for transmission, reflection, and absorption coefficients are provided and briefly discussed. (orig.)

  17. 4.2 GeV α-12C Elastic Scattering Based on α-Particle Model

    Institute of Scientific and Technical Information of China (English)

    YANG Yong-Xu; LU Xiao; LI Qing-Run

    2008-01-01

    Based on the a-particle model of 12C nucleus, the differential cross sections for α-12 C elastic scattering at incident energy of 4.2 GeV have been calculated within the framework of Glauber multiple scattering theory. The results show that the main features of the measured angular distribution of the cross sections can be reasonably described. The parameterizedα-α scattering amplitude, which is the basic input to construct the α-12C scattering Glauber amplitude in the a-particle model, is obtained by fitting the α-α scattering data.

  18. Elastic vector and axial scattering of weakly interacting particles off nuclei

    CERN Document Server

    Moreno, O

    2016-01-01

    We analyze the elastic scattering of particles interacting with nuclei through vector and axial currents with overall couplings of the order of the Standard Model weak interaction, or smaller; the dominant contribution to the elastic cross section is identified as the coherent component and is therefore spin-independent. Differential and integrated cross sections are obtained for a wide range of incident particle masses and velocities and for nuclear targets with different masses; vector, axial and overall couplings of the incident particle and of the hadronic target to the massive exchanged boson are also kept general. This study naturally encompasses several kinds of possible dark matter components, including active and sterile neutrinos or neutralinos, and addresses the prospects for their direct detection through elastic scattering off nuclei.

  19. Relativistic two-and three-particle scattering equations using instant and light-front dynamics

    International Nuclear Information System (INIS)

    Starting from the Bethe-Salpeter equation for two particles in the ladder approximation and integrating over the time component of momentum we derive three dimensional scattering integral equations satisfying constraints of unitarity and relativity, both employing the light-front and instant-form variables. The equations we arrive at are those first derived by Weinberg and by Blankenbecler and Sugar, and are shown to be related by a transformation of variables. Hence we show how to perform and relate identical dynamical calculation using these two equations. We extends this procedure to the case of three particles interacting via two-particle separable potentials. Using light-front and instant form variables we suggest a couple of three dimensional three-particle scattering equations satisfying constraints of two and three-particle unitarity and relativity. The three-particle light-front equation is shown to be approximately related by a transformation of variables to one of the instant-form three-particle equations. (author)

  20. Advanced analysis of polymer emulsions: Particle size and particle size distribution by field-flow fractionation and dynamic light scattering.

    Science.gov (United States)

    Makan, Ashwell C; Spallek, Markus J; du Toit, Madeleine; Klein, Thorsten; Pasch, Harald

    2016-04-15

    Field flow fractionation (FFF) is an advanced fractionation technique for the analyses of very sensitive particles. In this study, different FFF techniques were used for the fractionation and analysis of polymer emulsions/latexes. As model systems, a pure acrylic emulsion and emulsions containing titanium dioxide were prepared and analyzed. An acrylic emulsion polymerization was conducted, continuously sampled from the reactor and subsequently analyzed to determine the particle size, radius of gyration in specific, of the latex particles throughout the polymerization reaction. Asymmetrical flow field-flow fractionation (AF4) and sedimentation field-flow fractionation (SdFFF), coupled to a multidetector system, multi-angle laser light scattering (MALLS), ultraviolet (UV) and refractive index (RI), respectively, were used to investigate the evolution of particle sizes and particle size distributions (PSDs) as the polymerization progressed. The obtained particle sizes were compared against batch-mode dynamic light scattering (DLS). Results indicated differences between AF4 and DLS results due to DLS taking hydration layers into account, whereas both AF4 and SdFFF were coupled to MALLS detection, hence not taking the hydration layer into account for size determination. SdFFF has additional separation capabilities with a much higher resolution compared to AF4. The calculated radii values were 5nm larger for SdFFF measurements for each analyzed sample against the corresponding AF4 values. Additionally a low particle size shoulder was observed for SdFFF indicating bimodality in the reactor very early during the polymerization reaction. Furthermore, different emulsions were mixed with inorganic species used as additives in cosmetics and coatings such as TiO2. These complex mixtures of species were analyzed to investigate the retention and particle interaction behavior under different AF4 experimental conditions, such as the mobile phase. The AF4 system was coupled online

  1. Anomalous angular distributions in pion and α particle scattering to the 22+ state of 52Cr

    International Nuclear Information System (INIS)

    Inelastic scattering of 180 MeV π+ and π- from 52Cr shows an angular distribution for the 22+ state at 2.96 MeV that differs greatly from the usual L = 2 shapes for 2+ states. This state is perhaps the only case from pion-inelastic scattering in which standard distorted-wave impulse approximation models (including multistep and single-step responses) fail to reproduce the measured angular distribution. Furthermore, this unique excitation has been shown to have the features expected of a seniority-four proton excitation yet the pion data show charge symmetry. While coupled-channel calculations are not able to reproduce the pion data, they do agree with the shape observed for 42 MeV α particle scattering to this state, but the magnitude of the α scattering data is not consistent with a collective model and known γ ray deexcitations. Scattering to the first and third 2+ states of 52Cr with pions and α particles is also considered, and found to match the usual result for 2+ states in general, accentuating the anomaly of this 22+ transition. copyright 1996 The American Physical Society

  2. Alpha Particle Emitter Radiolabeled Antibody for Metastatic Cancer: What Can We Learn from Heavy Ion Beam Radiobiology?

    Directory of Open Access Journals (Sweden)

    Hong Song

    2012-06-01

    Full Text Available Alpha-particle emitter labeled monoclonal antibodies are being actively developed for treatment of metastatic cancer due to the high linear energy transfer (LET and the resulting greater biological efficacy of alpha-emitters. Our knowledge of high LET particle radiobiology derives primarily from accelerated heavy ion beam studies. In heavy ion beam therapy of loco-regional tumors, the modulation of steep transition to very high LET peak as the particle approaches the end of its track (known as the Bragg peak enables greater delivery of biologically potent radiation to the deep seated tumors while sparing normal tissues surrounding the tumor with the relatively low LET track segment part of the heavy ion beam. Moreover, fractionation of the heavy ion beam can further enhance the peak-to-plateau relative biological effectiveness (RBE ratio. In contrast, internally delivered alpha particle radiopharmaceutical therapy lack the control of Bragg peak energy deposition and the dose rate is determined by the administered activity, alpha-emitter half-life and biological kinetics of the radiopharmaceutical. The therapeutic ratio of tumor to normal tissue is mainly achieved by tumor specific targeting of the carrier antibody. In this brief overview, we review the radiobiology of high LET radiations learned from ion beam studies and identify the features that are also applicable for the development of alpha-emitter labeled antibodies. The molecular mechanisms underlying DNA double strand break repair response to high LET radiation are also discussed.

  3. Bayesian analysis of nanodosimetric ionisation distributions due to alpha particles and protons.

    Science.gov (United States)

    De Nardo, L; Ferretti, A; Colautti, P; Grosswendt, B

    2011-02-01

    Track-nanodosimetry has the objective to investigate the stochastic aspect of ionisation events in particle tracks, by evaluating the probability distribution of the number of ionisations produced in a nanometric target volume positioned at distance d from a particle track. Such kind of measurements makes use of electron (or ion) gas detectors with detecting efficiencies non-uniformly distributed inside the target volume. This fact makes the reconstruction of true ionisation distributions, which correspond to an ideal efficiency of 100%, non-trivial. Bayesian unfolding has been applied to ionisation distributions produced by 5.4 MeV alpha particles and 20 MeV protons in cylindrical volumes of propane of 20 nm equivalent size, positioned at different impact parameters with respect to the primary beam. It will be shown that a Bayesian analysis performed by subdividing the target volume in sub-regions of different detection efficiencies is able to provide a good reconstruction of the true nanodosimetric ionisation distributions. PMID:21112893

  4. Partition of cross sections in asymmetric nucleus-nucleus reactions and the origin of fast alpha particles

    International Nuclear Information System (INIS)

    To investigate the mechanism of asymmetric nucleus-nucleus reactions from the Coulomb barrier to intermediate energies the 14N + 159Tb reaction was studied at five bombarding energies between 8 and 23 MeV/u via particle-particle correlations (at selected energies) and particle KX-ray coincidences to identify the specific reaction channels. With the KX-ray method partial cross sections for projectile-like fragments (PLF) as a function of the atomic number (Z/sub res/) of the residual nucleus can be determined. The charge balance yields the ''missing charge'' dZ = Z/sub proj/ + Z/sub targ/ - Z/sub PLF/ - Z/sub TLF/ that indicates whether, in addition to the PLF, other charged particles are emitted. A large fraction of the inclusive cross sections is found to originate from such channels with two or more fragments in the exit channel, and this fraction increases as the PLF is further removed in mass from the incident projectile, and with increasing bombarding energy. From the particle-particle correlation studies it is found that sequential decays of PLF's are dominant. ''Non-sequential'' processes, if present, are associated with inelastic reactions involving excitations of both projectile and target. The bulk of the large alpha-particle cross section at small angles is found to be associated with channels in which, in addition to the alpha particle, only nucleons and other alpha particles are emitted. From γ-ray multiplicity measurements and from the broad distribution of the strength with Z/sub res/ it is concluded that these alpha particles originate from inelastic (damped) processes. 27 refs., 10 figs

  5. T-matrix method for electromagnetic scattering by a general anisotropic particle

    International Nuclear Information System (INIS)

    A general T-matrix solution for electromagnetic or light scattering by an anisotropic particle with an arbitrary permittivity tensor is constructed based on the extended boundary condition method (EBCM). By using the inverse Fourier transform, a system of quasi-spherical vector wave functions (qSVWFs) are obtained for an expansion representation of electromagnetic fields inside a general anisotropic medium. Special cases for gyroelectric anisotropic medium, biaxial anisotropic medium as well as uniaxial anisotropic medium are discussed. By virtue of the obtained series of qSVWFs, T-matrix formula are constructed to find solutions for characterizing electromagnetic or light scattering from an arbitrary shaped homogeneous anisotropic particle, and a home-made FORTRAN program is written. To validate the presented theoretical treatments as well as the home-made program, numerical results concerning radar cross section (RCS) or differential scattering cross sections (DSCSs) for various parameters are calculated by using the present method and are compared with those computed using other methods. Very good agreements are achieved, which partially confirms the correctness of the theoretical derivations and home-made program. Some new numerical results are also presented to analyze the influences of anisotropy components in permittivity tensor upon the scattering properties, which also provide a reference data for other methods. - Highlights: • A system of quasi-VSWFs is derived for expanding EM fields in a general anisotropic medium. • T-matrix solution for EM scattering by a general anisotropic particle is constructed based on EBCM. • Influences of anisotropy components upon the scattering properties are analyzed

  6. A refractive phase relation in light composite particle-nucleus elastic and inelastic scattering at intermediate energies

    International Nuclear Information System (INIS)

    We separate the angular distributions of light composite particle-nucleus elastic and inelastic scattering at intermediate energies, into ''positive'' and ''negative'' angle components. We show that if oscillations in the ''negative'' angle component of elastic scattering are due to refractive interference effects, there will be corresponding oscillations in the ''negative'' angle component of inelastic scattering which are in phase with those in the elastic scattering. This phase relation is independent of the multipolarity of the excitation

  7. Properties of an $\\alpha$ particle in a Bohrium $270$ Nucleus under the Generalized Symmetric Woods-Saxon Potential

    CERN Document Server

    Lütfüoğlu, B C

    2016-01-01

    The energy eigenvalues and the wave functions of an $\\alpha$ particle in a Bohrium $270$ nucleus were calculated by solving Schr\\"odinger equation for Generalized Symmetric Woods-Saxon potential. Using the energy spectrum by excluding and including the quasi-bound eigenvalues, entropy, internal energy, Helmholtz energy, and specific heat, as functions of reduced temperature were calculated. Stability and emission characteristics are interpreted in terms of the wave and thermodynamic functions. The kinetic energy of a decayed $\\alpha$ particle was calculated using the quasi-bound states, which is found close to the experimental value.

  8. Collisional stochastic ripple diffusion of alpha particles and beam ions on TFTR

    International Nuclear Information System (INIS)

    Predictions for ripple loss of fast ions from TFTR are investigated with a guiding center code including both collisional and ripple effects. A synergistic enhancement of fast ion diffusion is found for toroidal field ripple with collisions. The total loss is calculated to be roughly twice the sum of ripple and collisional losses calculated separately. Discrepancies between measurements and calculations of plasma beta at low current and large major radius are resolved when both effects are included for neutral beam ions. A 20--30% reduction in alpha particle heating is predicted for qa = 6--14, R = 2.6 m DT plasmas on TFTR due to first orbit and collisional stochastic ripple diffusion

  9. A route for polonium 210 production from alpha-particle irradiated bismuth-209 target

    International Nuclear Information System (INIS)

    A method is proposed for production of polonium-210 via the 209Bi(α,3n)210 At nuclear reaction. Bombardment of a bismuth-209 target was performed with a 37 MeV alpha-particle beam that leads to the production of astatine-210 (T1/2 = 8.1 h), which decays to polonium-210. It is purified from the bismuth target matrix by employing liquid-liquid extraction using tributyl phosphate (TBP) in para-xylene from 7 M hydrochloric acid. Back extraction of polonium-210 was performed by 9 M nitric acid. This method allows to purify a tracer amount of Po-210 (2.6 x 10-13 mol) from macroscopic amount of Bi (2.8 x 10-2 mol).

  10. Assessment of gamma, beta and alpha-particle-emitting nuclides in marine samples

    International Nuclear Information System (INIS)

    Depending on the physical properties of radionuclides different systems must be used for their measurement. Most convenient is if gamma spectrometry can be used by germanium, Silicon or Scintillation detectors (eg. NaI). If, however, the main emission consists of beta or alpha particles or low-energy photons as is the case for radionuclides decaying by electron capture, radiochemical separation and specific source preparations must be undertaken. In such cases also the radiochemical yield must be determined. The radiochemical part mainly follows the lines presented by prof. T. Jaakkola, Department of Radiochemistry, Helsinki, Finland, at a course in radioecology in Lurid, 1991. For very long-lived radionuclides other methods such as mass spectrometry are superior although often associated with sophisticated expensive instrumentation. (author)

  11. Gas production due to alpha particle degradation of polyethylene and polyvinylchloride

    International Nuclear Information System (INIS)

    Alpha particle degradation experiments were performed on polyethylene (PE) and polyvinylchloride (PVC) plastic samples typical of Westinghouse Savannah River Company (WSRC) transuranic (TRU) waste. This was done to evaluate the effects of sealing TRU waste during shipment. Experiments were conducted at three temperatures using low dose rates. Predominant products from both plastics were hydrogen, carbon dioxide, and various organic species, with the addition of hydrochloric acid from PVC. In all experiments, the total pressure decreased. Irradiation at 30 and 60 C and at various dose rates caused small changes for both plastics, but at 100 C coupled thermal-radiolytic effects included discoloration of the material as well as large differences in the gas phase composition

  12. Is the first excited state of the $\\alpha$-particle a breathing mode?

    CERN Document Server

    Bacca, Sonia; Leidemann, Winfried; Orlandini, Giuseppina

    2014-01-01

    The isoscalar monopole excitation of 4He is studied within a few-body ab initio approach. We consider the transition density to the low-lying and narrow 0+ resonance, as well as various sum rules and the strength energy distribution itself at different momentum transfers q. Realistic nuclear forces of chiral and phenomenological nature are employed. Various indications for a collective breathing mode are found: i) the specific shape of the transition density, ii) the high degree of exhaustion of the non-energy-weighted sum rule at low q and iii) the complete dominance of the resonance peak in the excitation spectrum. For the incompressibility K of the alpha-particle values between 20 and 30 MeV are found.

  13. Specific features of reactor or cyclotron {alpha}-particles irradiated beryllium microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Khomutov, A.M. [A.A.Bochvar All-Russia Research Inst. of Inorganic Materials (VNIINM), Moscow (Russian Federation); Gromov, B.F.; Karabanov, V.N. [and others

    1998-01-01

    Studies were carried out into microstructure changes accompanying helium swelling of Be reactor neutron irradiated at 450degC or {alpha}-particles implanted in cyclotron to reach the same volume accumulation of He (6-8 ncm{sup 3} He/cm{sup 3} Be). The microstructures of reactor irradiated and implanted samples were compared after vacuum anneal at 600-800degC up to 50h. The irradiated samples revealed the etchability along the grain boundaries in zones formed by adequately large equilibrium helium pores. The width of the zones increased with the annealing time and after 50h reached 30{mu}. Depleted areas 2-3{mu} dia were observed in some regions of near grain boundary zones. The roles of grain boundaries and manufacturing pores as vacancies` sources and helium sinks are considered. (author)

  14. Traversal of cells by radiation and absorbed fraction estimates for electrons and alpha particles

    International Nuclear Information System (INIS)

    Consideration of the pathlength which radiation traverses in a cell is central to algorithms for estimating energy deposition on a cellular level. Distinct pathlength distributions occur for radionuclides: (1) uniformly distributed in space about the cell (referred to as μ-randomness); (2) uniformly distributed on the surface of the cell (S-randomness); and (3) uniformly distributed within the cell volume (I-randomness). For a spherical cell of diameter d, the mean pathlengths are 2/3d, and 3/4d, respectively, for these distributions. Algorithms for simulating the path of radiation through a cell are presented and the absorbed fraction in the cell and its nucleus are tabulated for low energy electrons and alpha particles emitted on the surface of spherical cells. The algorithms and absorbed fraction data should be of interest to those concerned with the dosimetry of radionuclide-labeled monoclonal antibodies. 8 references, 3 figures, 2 tables

  15. Theory of small-angle multiple scattering of charged particles with consideration of geometrical interfaces

    International Nuclear Information System (INIS)

    Applying the small-angle multiple scattering theory of Rossi and Greisen, especially the pencil-beam solution supplied by E. Fermi, we have solved two boundary surface problems of multiple scattering of electrons and other charged particles in the energy range of radiation therapy. In the validity range of the small-angle approximation, the number and the angular distribution of the scattered electrons leaving the lateral surface of an electron-irradiated absorber block have been correctly calculated. The essential step has been to find a continuous solution describing the transition from inner to outer space of the absorber. Furthermore, the phenomenon of 'quasi-reflexion', occurring when electrons are entering a boundary plane under a small entrance angle, has been correctly reproduced as an analytical result. The correctness of the analytical results was checked by comparison with a highly accurate, own Monte-Carlo program. We are planning to extend the theoretical treatment by considering large-angle scattering as well. In the framework of radiation therapy with electrons and hadrons, the present results can be applied to understand and quantitatively estimate the effects of 'in-scattering' into air-filled cavities of the irradiated body or of ionization chambers, of scattering at collimator edges and of 'quasi-reflexion' in the case of small-angle incidence into applicator cone walls. (orig.)

  16. Long-Range Alpha Particle Emission in the Fission of U235 by 3-MeV Neutrons

    International Nuclear Information System (INIS)

    The energy and angular distribution of long-range alpha particles emitted in the fission of U235 induced by 3-MeV neutrons have been measured. The alpha panicles were detected by solid-state detector and the fission fragments were detected by a gas scintillation counter. The neutrons were produced by the T (p, n) He3 reaction using a 5.5- MeV Van de Graaff accelerator. About 3000 fission events accompanied by the emission of a high-energy alpha panicle were recorded. The most probable energy of the alpha particles is between 15-16 MeV. and the energy distribution has a full width at half maximum of about D MeV, which is the same as observed in tliermal- neutron fission. The angular distribution of the long-range alpha panicles with respect to the incident neutron direction was found to be forward-peaked, in agreement with previous work on alpha emission in 14-MeV neutron-induced fission of LP. At angles of 0° and 90° with respect to the incident neutron direction the alpha panicles were detected with an angular spread of about ± 25°. The anisotropy [Nα(0°)/ Nα(90°)] was found to be 1.320 ± 0.12. This value is in agreement with the anisotropy calculated on the basis of statistical evaporation of panicles. The results of the present investigation are consistent with the hypothesis that the emission of long-range alpha panicles in fission is an evaporation process. The implications of the results of this work and of other recent investigations on long-range alpha emission are discussed. (author)

  17. A Complete Order-$\\alpha^3$ Calculation of the Cross Section for Polarized Compton Scattering

    CERN Document Server

    Swartz, M L

    1998-01-01

    The construction of a computer code to calculate the cross sections for the spin-polarized processes e-gamma=>e-gamma,e-gamma-gamma,e-e+e- to order-alpha**3 is described. The code calculates cross sections for circularly-polarized initial-state photons and arbitrarily polarized initial-state electrons. The application of the code to the SLD Compton polarimeter indicates that the order-alpha**3 corrections produce a fractional shift in the SLC polarization scale of -0.1% which is too small and of the wrong sign to account for the discrepancy in the Z-pole asymmetries measured by the SLD Collaboration and the LEP Collaborations.

  18. Microwave imaging for conducting scatterers by hybrid particle swarm optimization with simulated annealing

    International Nuclear Information System (INIS)

    In this paper, a microwave imaging technique for reconstructing the shape of two-dimensional perfectly conducting scatterers by means of a stochastic optimization approach is investigated. Based on the boundary condition and the measured scattered field derived by transverse magnetic illuminations, a set of nonlinear integral equations is obtained and the imaging problem is reformulated in to an optimization problem. A hybrid approximation algorithm, called PSO-SA, is developed in this work to solve the scattering inverse problem. In the hybrid algorithm, particle swarm optimization (PSO) combines global search and local search for finding the optimal results assignment with reasonable time and simulated annealing (SA) uses certain probability to avoid being trapped in a local optimum. The hybrid approach elegantly combines the exploration ability of PSO with the exploitation ability of SA. Reconstruction results are compared with exact shapes of some conducting cylinders; and good agreements with the original shapes are observed.

  19. DOA estimation for local scattered CDMA signals by particle swarm optimization.

    Science.gov (United States)

    Chang, Jhih-Chung

    2012-01-01

    This paper deals with the direction-of-arrival (DOA) estimation of local scattered code-division multiple access (CDMA) signals based on a particle swarm optimization (PSO) search. For conventional spectral searching estimators with local scattering, the searching complexity and estimating accuracy strictly depend on the number of search grids used during the search. In order to obtain high-resolution and accurate DOA estimation, a smaller grid size is needed. This is time consuming and it is unclear how to determine the required number of search grids. In this paper, a modified PSO is presented to reduce the required search grids for the conventional spectral searching estimator with the effects of local scattering. Finally, several computer simulations are provided for illustration and comparison. PMID:22737004

  20. ON THE RELATIVE SPEED AND TEMPERATURE RATIO OF SOLAR WIND ALPHA PARTICLES AND PROTONS: COLLISIONS VERSUS WAVE EFFECTS

    International Nuclear Information System (INIS)

    We study the relative flow speed and the temperature ratio of alpha particles and protons and their connections to the helium ion abundance, the collisional age, and the power of transverse fluctuations within the inertial range. It is found that the alpha-to-proton temperature ratio, Tα/Tp , anti-correlates with the helium ion abundance. Despite a relatively high collisional age and small wave power, the ratio Tα/Tp can reach comparatively high values (even above 2) whenever the helium ion abundance is below about 0.02. In contrast, the differential speed of alpha particles with respect to protons is correlated with the total wave power and anti-correlated with the collisional age. Ultimately, the individual heating of each ion species is positively correlated with the total wave power. Our findings suggest that a high-friction collision could be efficient in reducing the differential speed between alpha particles and protons, but appears not to be sufficient to equalize the alpha and proton temperatures, i.e., to make Tα ≅ Tp . This is a hint that the local wave heating process is acting on a timescale shorter than the collision time.