WorldWideScience

Sample records for radiative neutron decay

  1. Particle and photon detection for a neutron radiative decay experiment

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, T.R. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)], E-mail: thomas.gentile@nist.gov; Dewey, M.S.; Mumm, H.P.; Nico, J.S.; Thompson, A.K. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Chupp, T.E. [University of Michigan, Ann Arbor, MI 48109 (United States); Cooper, R.L. [University of Michigan, Ann Arbor, MI 48109 (United States)], E-mail: cooperrl@umich.edu; Fisher, B.M.; Kremsky, I.; Wietfeldt, F.E. [Tulane University, New Orleans, LA 70118 (United States); Kiriluk, K.G.; Beise, E.J. [University of Maryland, College Park, MD 20742 (United States)

    2007-08-21

    We present the particle and photon detection methods employed in a program to observe neutron radiative beta-decay. The experiment is located at the NG-6 beam line at the National Institute of Standards and Technology Center for Neutron Research. Electrons and protons are guided by a 4.6 T magnetic field and detected by a silicon surface barrier detector. Photons with energies between 15 and 750 keV are registered by a detector consisting of a bismuth germanate scintillator coupled to a large area avalanche photodiode. The photon detector operates at a temperature near 80 K in the bore of a superconducting magnet. We discuss CsI as an alternative scintillator, and avalanche photodiodes for direct detection of photons in the 0.1-10 keV range.

  2. Standard model treatment of the radiative corrections to the neutron β-decay

    International Nuclear Information System (INIS)

    Bunatyan, G.G.

    2003-01-01

    Starting with the basic Lagrangian of the Standard Model, the radiative corrections to the neutron β-decay are acquired. The electroweak interactions are consistently taken into consideration amenably to the Weinberg-Salam theory. The effect of the strong quark-quark interactions on the neutron β-decay is parametrized by introducing the nucleon electromagnetic form factors and the weak nucleon transition current specified by the form factors g V , g A , ... The radiative corrections to the total decay probability W and to the asymmetry coefficient of the momentum distribution A are obtained to constitute δW ∼ 8.7 %, δA ∼ -2 %. The contribution to the radiative corrections due to allowance for the nucleon form factors and the nucleon excited states amounts up to a few per cent of the whole value of the radiative corrections. The ambiguity in description of the nucleon compositeness is surely what causes the uncertainties ∼ 0.1 % in evaluation of the neutron β-decay characteristics. For now, this puts bounds to the precision attainable in obtaining the element V ud of the CKM matrix and the g V , g A , ... values from experimental data processing

  3. Neutron emission from 9Be nucleus under the action of β+ and γ radiation emitted in radioactive decay

    International Nuclear Information System (INIS)

    Vo Dak Bang; Gangrskij, Yu.P.; Miller, M.B.; Mikhajlov, L.V.; Fam Zui Khien; Kharisov, I.F.

    1980-01-01

    The neutron yield from the 9 Be nucleus under the action of beta and gamma-radiation emitted at the radiative decay of 11 C, 62 Cu, 66 Ga, 74 Br isotopes is measured. These isotopes differ essentially by the emitted radiation spectra. The contribution of various processes ((γ, n)-reactions, inelastic scattering and positron nonradiative annihilation) to the neutron yield observed is determined [ru

  4. An experiment for the precision measurement of the radiative decay mode of the neutron

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.L., E-mail: cooperrl@umich.ed [University of Michigan, Ann Arbor, MI 48109 (United States); Bass, C.D. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Beise, E.J.; Breuer, H. [University of Maryland, College Park, MD 20742 (United States); Byrne, J. [University of Sussex, BN1 9QH (United Kingdom); Chupp, T.E. [University of Michigan, Ann Arbor, MI 48109 (United States); Coakley, K.J. [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Dewey, M.S.; Fisher, B.M.; Fu, C.; Gentile, T.R. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); McGonagle, M. [University of Maryland, College Park, MD 20742 (United States); Mumm, H.P.; Nico, J.S.; Thompson, A.K. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Wietfeldt, F.E. [Tulane University, New Orleans, LA 70118 (United States)

    2009-12-11

    The familiar neutron decay into a proton, electron, and antineutrino can be accompanied by photons with sufficient energy to be detected. We recently reported the first observation of the radiative beta decay branch for the free neutron with photons of energy 15-340 keV. We performed the experiment in the bore of a superconducting magnet where electron, proton, and photon signals were measured. A bar of bismuth germanate scintillating crystal coupled to an avalanche photodiode served as the photon detector that operated in the cryogenic, high magnetic field environment. The branching ratio for this energy region was measured and is consistent with the theoretical calculation. An experiment is under way to measure the branching ratio with an improved precision of 1% relative standard uncertainty and to measure the photon energy spectrum. In this paper, the apparatus modifications to reduce the systematic uncertainties will be described. Central to these improvements is the development of a 12-element detector based on the original photon detector design that will improve the statistical sensitivity. During data acquisition, a detailed calibration program will be performed to improve the systematic uncertainties. The development of these modifications is currently under way, and the second run of the experiment commenced in July 2008.

  5. Direct detection of albedo neutron decay electrons at the inner edge of the radiation belt and experimental determination of neutron density in near-Earth space

    Science.gov (United States)

    Li, X.; Selesnick, R.; Schiller, Q. A.; Zhang, K.; Zhao, H.; Baker, D. N.; Temerin, M. A.

    2017-12-01

    The galaxy is filled with cosmic ray particles, mostly protons with kinetic energy above hundreds of mega-electron volts (MeV). Soon after the discovery of Earth's Van Allen radiation belts almost six decades ago, it was recognized that the main source of inner belt protons, with kinetic energies of tens to hundreds of MeV, is Cosmic Ray Albedo Neutron Decay (CRAND). In this process, cosmic rays reaching the upper atmosphere from throughout the galaxy interact with neutral atoms to produce albedo neutrons which, being unstable to 𝛽 decay, are a potential source of geomagnetically trapped protons and electrons. Protons retain most of the neutrons' kinetic energy while the electrons have lower energies, mostly below 1 MeV. The viability of the electron source was, however, uncertain because measurements showed that electron intensity can vary greatly while the neutron decay rate should be almost constant. Recent measurements from the Relativistic Electron and Proton Telescope integrated little experiment (REPTile) onboard the Colorado Student Space Weather Experiment (CSSWE) CubeSat now show that CRAND is the main electron source for the radiation belt near its inner edge, and also contributes to the inner belt elsewhere. Furthermore, measurement of the CRAND electron intensity provides the first experimental determination of the neutron density in near-Earth space, 2x10-9/cm3, confirming earlier theoretical estimates.

  6. Weak radiative hyperon decays

    International Nuclear Information System (INIS)

    Roberts, B.L.; Booth, E.C.; Gall, K.P.; McIntyre, E.K.; Miller, J.P.; Whitehouse, D.A.; Bassalleck, B.; Hall, J.R.; Larson, K.D.; Wolfe, D.M.; Fickinger, W.J.; Robinson, D.K.; Hallin, A.L.; Hasinoff, M.D.; Measday, D.F.; Noble, A.J.; Waltham, C.E.; Hessey, N.P.; Lowe, J.; Horvath, D.; Salomon, M.

    1990-01-01

    New measurements of the Σ + and Λ weak radiative decays are discussed. The hyperons were produced at rest by the reaction K - p → Yπ where Y = Σ + or Λ. The monoenergetic pion was used to tag the hyperon production, and the branching ratios were determined from the relative amplitudes of Σ + → pγ to Σ + → pπ 0 and Λ → nγ to Λ → nπ 0 . The photons from weak radiative decays and from π 0 decays were detected with modular NaI arrays. (orig.)

  7. Measurable distributions of unpolarized neutron decay

    International Nuclear Information System (INIS)

    Glueck, F.

    1992-05-01

    Several two- and one-dimensional distributions of unpolarized free neutron decay are calculated. The results of the order-α model independent radiative correction calculations are tabulated numerically. With these corrections the theoretical distributions become precise enough to make possible the determination of the ratio of the axial-vector to the vector weak coupling constants to a precision of ∼0.001. (author) 39 refs.; 7 tabs

  8. General trend and local variations of neutron resonance cascade gamma-decay radiative strength functions

    International Nuclear Information System (INIS)

    Sukhovoj, A.M.; Furman, W.I.; Khitrov, V.A.; Jovancevic, N.

    2012-01-01

    A new hypothesis on the dependence of the form of the radiative strength functions of electric and magnetic dipole gamma transitions in a heated nucleus on the excited level density was suggested and tested experimentally. For this purpose, the region of possible values of random values of the level density and radiative strength functions which precisely reproduced experimental intensity of two-step cascades for 41 nuclei from 40K to 200Hg was determined. It was obtained that the suggested hypothesis can provide the maximal increase of radiative strength functions values by order of magnitude in comparison with existing notations as a result of collective effects enhancement. This result points to the necessity to take into account this possibility in existing and future models of radiative strength functions

  9. Pulsed radiation decay logging

    International Nuclear Information System (INIS)

    Mills, W.R. Jr.

    1983-01-01

    There are provided new and improved well logging processes and systems wherein the detection of secondary radiation is accomplished during a plurality of time windows in a manner to accurately characterize the decay rate of the secondary radiation. The system comprises a well logging tool having a primary pulsed radiation source which emits repetitive time-spaced bursts of primary radiation and detector means for detecting secondary radiation resulting from the primary radiation and producing output signals in response to the detected radiation. A plurality of measuring channels are provided, each of which produces a count rate function representative of signals received from the detector means during successive time windows occurring between the primary radiation bursts. The logging system further comprises means responsive to the measuring channels for producing a plurality of functions representative of the ratios of the radiation count rates measured during adjacent pairs of the time windows. Comparator means function to compare the ratio functions and select at least one of the ratio functions to generate a signal representative of the decay rate of the secondary radiation

  10. Neutron decay, semileptonic hyperon decay and the Cabibbo model

    International Nuclear Information System (INIS)

    Siebert, H.W.

    1989-01-01

    The decay rates and formfactor ratios of neutron decay and semileptonic hyperon decays are compared in the framework of the Cabibbo model. The results indicate SU(3) symmetry breaking. The Kobayashi-Maskawa matrix element V us determined from these decays is in good agreement with the value determined from K→πeν decays, and with unitarity of the KM-matrix. (orig.)

  11. Neutron Decay with PERC: a Progress Report

    International Nuclear Information System (INIS)

    Konrad, G; Abele, H; Erhart, J; Fillunger, H; Gösselsberger, C; Horvath, M; Jericha, E; Klauser, C; Maix, R K; Nowak, S; Sauerzopf, C; Beck, M; Heil, W; Drescher, C; Dubbers, D; Märkisch, B; Mest, H; Rebrova, N; Roick, C; Klenke, J

    2012-01-01

    The PERC collaboration will perform high-precision measurements of angular correlations in neutron beta decay at the beam facility MEPHISTO of the Forschungs-Neutronenquelle Heinz Maier-Leibnitz in Munich, Germany. The new beam station PERC, a clean, bright, and versatile source of neutron decay products, is designed to improve the sensitivity of neutron decay studies by one order of magnitude. The charged decay products are collected by a strong longitudinal magnetic field directly from inside a neutron guide. This combination provides the highest phase space density of decay products. A magnetic mirror serves to perform precise cuts in phase space, reducing related systematic errors. The new instrument PERC is under development by an international collaboration. The physics motivation, sensitivity, and applications of PERC as well as the status of the design and preliminary results on uncertainties in proton spectroscopy are presented in this paper.

  12. Correlation coefficients in neutron β-decay

    International Nuclear Information System (INIS)

    Byrne, J.

    1978-01-01

    The various angular and polarisation coefficients in neutron decay are the principal sources of information on the β-interaction. Measurements of the electron-neutrino angular correlation coefficient (a), the neutron-spin-electron-momentum correlation coefficient (A), the neutron-spin-neutrino-momentum correlation coefficient (B), and the triple correlation coefficient D and time-reversal invariance are reviewed and the results discussed. (U.K.)

  13. RADIATIVE PENGUIN DECAYS FROM BABAR

    Energy Technology Data Exchange (ETDEWEB)

    Eigen, Gerald

    2003-08-28

    Electroweak penguin decays provide a promising hunting ground for Physics beyond the Standard Model (SM). The decay B {yields} X{sub s}{gamma}, which proceeds through an electromagnetic penguin loop, already provides stringent constraints on the supersymmetric (SUSY) parameter space. The present data samples of {approx}1 x 10{sup 8} B{bar B} events allow to explore radiative penguin decays with branching fractions of the order of 10{sup -6} or less. In this brief report they discuss a study of B {yields} K*{ell}{sup +}{ell}{sup -} decay modes and a search for B {yields} {rho}({omega}){gamma} decays.

  14. General classification and analysis of neutron β-decay experiments

    International Nuclear Information System (INIS)

    Gudkov, V.; Greene, G.L.; Calarco, J.R.

    2006-01-01

    A general analysis of the sensitivities of neutron β-decay experiments to manifestations of possible interaction beyond the standard model is carried out. In a consistent fashion, we take into account all known radiative and recoil corrections arising in the standard model. This provides a description of angular correlations in neutron decay in terms of one parameter, which is accurate to the level of ∼10 -5 . Based on this general expression, we present an analysis of the sensitivities to new physics for selected neutron decay experiments. We emphasize that the usual parametrization of experiments in terms of the tree-level coefficients a,A, and B is inadequate when the experimental sensitivities are at the same or higher level relative to the size of the corrections to the tree-level description

  15. Examining the possibility to observe neutron dark decay in nuclei

    Science.gov (United States)

    Pfützner, M.; Riisager, K.

    2018-04-01

    As proposed recently by Fornal and Grinstein, neutrons can undergo a dark matter decay mode which has not yet been observed. Such a decay could explain the existing discrepancy between two different methods of neutron lifetime measurements. If such neutron decay is possible, then it should occur also in nuclei with sufficiently low neutron binding energy. We examine a few nuclear candidates for the dark neutron decay and we consider the possibilities of their experimental identification. In more detail we discuss the case of 11Be which appears as the most promising nucleus for the observation of neutron dark decay.

  16. Examining the possibility to observe neutron dark decay in nuclei

    DEFF Research Database (Denmark)

    Pfutzner, M.; Riisager, K.

    2018-01-01

    also in nuclei with sufficiently low neutron binding energy. We examine a few nuclear candidates for the dark neutron decay and we consider the possibilities of their experimental identification. In more detail we discuss the case of Be-11 which appears as the most promising nucleus for the observation......As proposed recently by Fornal and Grinstein, neutrons can undergo a dark matter decay mode which has not yet been observed. Such a decay could explain the existing discrepancy between two different methods of neutron lifetime measurements. If such neutron decay is possible, then it should occur...... of neutron dark decay....

  17. Meson radiative decays

    International Nuclear Information System (INIS)

    Edwards, B.J.; Kamal, A.N.

    1979-04-01

    The status of decays of the kind V → Pγ and P → Vγviewed with special emphasis on the work done by the authors in this field. The low experimental value of GAMMA(rho → πγ) remains the outstanding problem. The lastest preliminary numbers from a Fermi Laboratory experiment go in the right direction but not far enough. 15 references

  18. Method for determining thermal neutron decay times of earth formations

    International Nuclear Information System (INIS)

    Arnold, D.M.

    1976-01-01

    A method is disclosed for measuring the thermal neutron decay time of earth formations in the vicinity of a well borehole. A harmonically intensity modulated source of fast neutrons is used to irradiate the earth formations with fast neutrons at three different intensity modulation frequencies. The tangents of the relative phase angles of the fast neutrons and the resulting thermal neutrons at each of the three frequencies of modulation are measured. First and second approximations to the earth formation thermal neutron decay time are derived from the three tangent measurements. These approximations are then combined to derive a value for the true earth formation thermal neutron decay time

  19. Radiative Leptonic B Decays

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Edward Tann [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2007-01-01

    We present the results of a search for B+ meson decays into γℓ+v, where ℓ = e,μ. We use a sample of 232 million B$\\bar{B}$ meson pairs recorded at the Υ(4S) resonance with the BABAR detector at the PEP-II B factory. We measure a partial branching fraction Δβ in a restricted region of phase space that reduces the effect of theoretical uncertainties, requiring the lepton energy to be in the range 1.875 and 2.850 GeV, the photon energy to be in the range 0.45 and 2.35 GeV, and the cosine of the angle between the lepton and photon momenta to be less than -0.36, with all quantities computed in the Υ(4S) center-of-mass frame. We find Δβ(B+ → γℓ+v) = (-0.31.5+1.3(statistical) -0.6+0.6(systematic) ± 0.1(theoretical)) x 10-6, under the assumption of lepton universality. Interpreted as a 90% confidence-level Bayesian upper limit, the result corresponds to 1.7 x 10-6 for a prior at in amplitude, and 2.3 x 10-6 for a prior at in branching fraction.

  20. Neutron β Decay: Status and Future of the Asymmetry Measurement

    International Nuclear Information System (INIS)

    Ito, Takeyasu M.

    2007-01-01

    With more intense sources of cold and ultracold neutrons becoming available and with improved experimental techniques being developed, determination of IV ud l from neutron β decay with a similar precision to that from from superallowed β decays is within reach. Determination of IV ud l from neutron β decay, free from nuclear corrections, holds the most promise for a further improvement of the determination of IV ud I l· The current and future neutron β decay correlation experiments including the UCNA experiment at Los Alamos National Laboratory are reviewed.

  1. On the proton spectrum in free neutron β-decay

    International Nuclear Information System (INIS)

    Bunatyan, G.G.

    2000-01-01

    We consider the calculations which are appropriate to acquire with a high precision, of ∼ 1% or better, the general characteristics of weak interactions from the experiments on the free neutron β-decay; the principle emphasis is placed on the phenomena associated with the recoil of protons. The part played by electromagnetic interactions in β-decay is visualized, with special attention drawn to the influence of the γ-radiation on the momentum distribution of the particles in the final state. The effect of electromagnetic interactions on the proton recoil spectrum is studied, in the light of the experiments which are carried out and planned for now. The results of the calculations, which are to be confronted with the experimental data, are presented upright in terms of the effective Lagrangian underlying the inquiry. Owing to electromagnetic interactions, the corrections to the energy distribution of protons prove to amount to the value of a few per cent. Nowadays, this is substantial to obtain with a high accuracy the characteristics of weak interactions by processing the data of the experiments on the proton distribution in the free neutron β-decay

  2. Limits on Tensor Coupling from Neutron $\\beta$-Decay

    OpenAIRE

    Pattie Jr, Robert W.; Hickerson, Kevin P.; Young, Albert R.

    2013-01-01

    Limits on the tensor couplings generating a Fierz interference term, b, in mixed Gamow-Teller Fermi decays can be derived by combining data from measurements of angular correlation parameters in neutron decay, the neutron lifetime, and $G_{\\text{V}}=G_{\\text{F}} V_{ud}$ as extracted from measurements of the $\\mathcal{F}t$ values from the $0^{+} \\to 0^{+}$ superallowed decays dataset. These limits are derived by comparing the neutron $\\beta$-decay rate as predicted in the standard model with t...

  3. Weak radiative baryonic decays of B mesons

    International Nuclear Information System (INIS)

    Kohara, Yoji

    2004-01-01

    Weak radiative baryonic B decays B→B 1 B 2 -barγ are studied under the assumption of the short-distance b→sγ electromagnetic penguin transition dominance. The relations among the decay rates of various decay modes are derived

  4. LHCb: Radiative Decays at LHCb

    CERN Multimedia

    Orlandea, M

    2013-01-01

    In this work we present a measurement of the ratio of the branching fraction of the radiative decays $B^{0}\\rightarrow K^{*0}\\gamma$ and $B^{0}_{s}\\rightarrow \\phi\\gamma$ using 1.0 fb$^{-1}$ of data taken with the LHCb detector. The value obtained is \\begin{equation} \\frac{B\\left(B^{0}\\rightarrow K^{*0}\\gamma\\right)}{B\\left(B^{0}_{s}\\rightarrow \\phi\\gamma\\right)}=1.23\\pm0.06(stat.)\\pm0.04(syst.)\\pm0.10\\left(f_s/f_d\\right) \\end{equation} Using the world average value $B\\left(B^{0}\\rightarrow K^{*0}\\gamma\\right)=\\left(4.33\\pm0.15\\right)\\times10^{-5}$ branching fraction is determined to be $B\\left(B^{0}_{s}\\rightarrow \\phi\\gamma\\right)=3.5\\pm0.4\\times10^{-5}$. A measurement of the direct CP asymmetry of the decay $B^{0}\\rightarrow K^{*0}\\gamma$ is also presented. Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations.

  5. Neutron radiation capture

    International Nuclear Information System (INIS)

    1986-01-01

    For all stable and experimentally studied radionuclides evaluated data are presented on cross sections of thermal neutrons, on resonance integrals and medium neutron cross sections with energy of 30 KeV. Refs, figs and tabs

  6. Method for simultaneous measurement of borehole and formation neutron decay-times employing iterative fitting

    International Nuclear Information System (INIS)

    Schultz, W.E.

    1982-01-01

    A method is described of making in situ measurements of the thermal neutron decay time of earth formations in the vicinity of a wellbore. The borehole and earth formations in its vicinity are repetitively irradiated with pulsed fast neutrons and, during the intervals between pulses, capture gamma radiation is measured in at least four, non-overlapping, contiguous time intervals. A background radiation measurement is made between successive pulses and used to correct count-rates representative of thermal neutron populations in the borehole and the formations, the count-rates being generated during each of the time intervals. The background-corrected count-rate measurements are iteratively fitted to exponential curves using a least squares technique to simultaneously derive signals representing borehole component and formation component of the thermal neutron decay time. The signals are recorded as a function of borehole depth. (author)

  7. The Standard Model and the neutron beta-decay

    CERN Document Server

    Abele, H

    2000-01-01

    This article reviews the relationship between the observables in neutron beta-decay and the accepted modern theory of particle physics known as the Standard Model. Recent neutron-decay measurements of various mixed American-British-French-German-Russian collaborations try to shed light on the following topics: the coupling strength of charged weak currents, the universality of the electroweak interaction and the origin of parity violation.

  8. Time reversal violation in radiative beta decay: experimental plans

    Science.gov (United States)

    Behr, J. A.; McNeil, J.; Anholm, M.; Gorelov, A.; Melconian, D.; Ashery, D.

    2017-01-01

    Some explanations for the excess of matter over antimatter in the universe involve sources of time reversal violation (TRV) in addition to the one known in the standard model of particle physics. We plan to search for TRV in a correlation between the momenta of the beta, neutrino, and the radiative gamma sometimes emitted in nuclear beta decay. Correlations involving three (out of four) momenta are sensitive at lowest order to different TRV physics than observables involving spin, such as electric dipole moments and spin-polarized beta decay correlations. Such experiments have been done in radiative kaon decay, but not in systems involving the lightest generation of quarks. An explicit low-energy physics model being tested produces TRV effects in the Fermi beta decay of the neutron, tritium, or some positron-decaying isotopes. We will present plans to measure the TRV asymmetry in radiative beta decay of laser-trapped 38mK at better than 0.01 sensitivity, including suppression of background from positron annihilation. Supported by NSERC, D.O.E., Israel Science Foundation. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada.

  9. Review of meson resonance radiative decays

    International Nuclear Information System (INIS)

    Thorndike, E.H.

    1977-01-01

    The radiative decays of meson resonances can be studied by three different approaches, it is noted. These are the meson-exchange, Primakoff effect, and the production of the desired resonance and subsequent observation of its decay. These approaches are criticized and examples of them are reviewed. Mass distributions are shown and branching ratios discussed. 21 references

  10. Fission decay properties of ultra neutron-rich uranium isotopes

    Indian Academy of Sciences (India)

    in the chain of neutron-rich uranium isotopes is examined here. The neutron ... mean field theory, this nucleus is shown to undergo exotic decay mode of thermal neu- .... For 250U with a fission barrier of 4.3 MeV [5], we obtain the value of.

  11. Search for radiative B meson decays

    International Nuclear Information System (INIS)

    Lesiak, T.; Muryn, B.; Nowak, G.; Antreasyan, D.; Irion, J.; McBride, P.; Strauch, K.; Bartels, H.W.; Bienlein, J.K.; Brockmueller, K.; Jakubowski, Z.; Karch, K.; Kloiber, T.; Koch, W.; Maschmann, W.; Meyer, H.; Skwarnicki, T.; Trost, H.J.; Voigt, A.; Wachs, K.; Zschorsch, P.; Besset, D.; Cabenda, R.; Cowan, R.; Bieler, C.; Graaf, K.; Heinsius, F.H.; Kiel, T.; Krueger, S.; Lekebusch, R.; Nernst, R.; Sievers, D.; Stock, V.; Strohbusch, U.; Bloom, E.D.; Clare, R.; Cooper, S.; Fairfield, K.; Fridman, A.; Gaiser, J.; Gelphman, D.; Godfrey, G.; Hofstadter, R.; Kirkbride, I.; Lee, R.; Leffler, S.; Litke, A.M.; Lockman, W.; Lowe, S.; Niczyporuk, B.; Pollock, B.; Schwarz, A.; Tompkins, J.; Van Uitert, B.; Wacker, K.; Brock, I.; Engler, A.; Kraemer, R.W.; Marlow, D.; Messing, F.; Prindle, D.; Renger, B.; Rippich, C.; Vogel, H.; Cavalli-Sforza, M.; Coyne, D.; Folger, G.; Glaser, G.; Kobel, M.; Lurz, B.; Schuette, J.; Volland, U.; Wegener, H.; Janssen, H.; Koenig, A.C.; Metzger, W.J.; Reidenbach, M.; Schotanus, J.; Walle, R.T. van de; Walk, W.; Keh, S.; Kilian, H.; Koenigsmann, K.; Scheer, M.; Schmitt, P.; Marsiske, H.; Peck, C.; Porter, F.C.; Ratoff, P.; Williams, D.A.

    1991-07-01

    The Crystal Ball detector at the ε + ε - storage ring DORIS-II has been used to search for radiative B meson decays, especially of the type b→sγ. No mono-energetic γ-lines have been found in the inclusive photon spectrum from Υ(4S) decays, and upper limits are obtained for radiative decays of B mesons to various strange mesons and to the D*. Integrating the photon spectrum over the corresponding energy range, we find BR(B→γX) -3 at 90% confidence level for the mass range 892 MeV≤M X ≤2045 MeV. (orig.)

  12. Search for radiative B meson decays

    International Nuclear Information System (INIS)

    Lesiak, T.; Muryn, B.; Nowak, G.; Antreasyan, D.; Irion, J.; McBride, P.; Strauch, K.; Bartels, H.W.; Bienlein, J.K.; Brockmueller, K.; Jakubowski, Z.; Karch, K.; Kloiber, T.; Koch, W.; Maschmann, W.; Meyer, H.; Skwarnicki, T.; Trost, H.J.; Voigt, A.; Wachs, K.; Zschorsch, P.; Besset, D.; Cabenda, R.; Cowan, R.; Bieler, C.; Graaf, K.; Heinsius, F.H.; Kiel, T.; Krueger, S.; Lekebusch, R.; Nernst, R.; Sievers, D.; Stock, V.; Strohbusch, U.; Bloom, E.D.; Clare, R.; Cooper, S.; Fairfield, K.; Fridman, A.; Gaiser, J.; Gelphman, D.; Godfrey, G.; Hofstadter, R.; Kirkbride, I.; Lee, R.; Leffler, S.; Litke, A.M.; Lockman, W.; Lowe, S.; Niczyporuk, B.; Pollock, B.; Schwarz, A.; Tompkins, J.; Van Uitert, B.; Wacker, K.; Brock, I.; Engler, A.; Kraemer, R.W.; Marlow, D.; Messing, F.; Prindle, D.; Renger, B.; Rippich, C.; Vogel, H.; Cavalli-Sforza, M.; Coyne, D.; Folger, G.; Glaser, G.; Kobel, M.; Lurz, B.; Schuette, J.; Volland, U.; Wegener, H.; Janssen, H.; Koenig, A.C.; Metzger, W.J.; Reidenbach, M.; Schotanus, J.; Walle, R.T. van de; Walk, W.; Keh, S.; Kilian, H.; Koenigsmann, K.; Scheer, M.; Schmitt, P.; Marsiske, H.; Williams, D.A.

    1992-01-01

    The Crystal Ball detector at the e + e - storage ring DORIS-II has been used to search for radiative B meson decays, especially of the type b→sγ. No mono-energetic γ-lines have been found in the inclusive photon spectrum from Υ(4S) decays, and upper limits are obtained for radiative decays of B mesons to various strange mesons and to the D*. Integrating the photon spectrum over the corresponding energy range, we find BR(B→γX) -3 , at 90% confidence level for the mass range 892 MeV≤M X ≤2045 MeV. (orig.)

  13. Neutron induced radiation damage

    International Nuclear Information System (INIS)

    Williams, M.M.R.

    1977-01-01

    We derive a general expression for the number of displaced atoms of type j caused by a primary knock-on of type i. The Kinchin-Pease model is used, but considerably generalised to allow for realistic atomic potentials. Two cases are considered in detail: the single particle problem causing a cascade and the neutron initiated problem which leads to multiple subcascades. Numerical results have been obtained for a variety of scattering laws. An important conclusion is that neutron initiated damage is much more severe than atom-initiated damage and leads to the number of displaced atoms being a factor of (A+1) 2 /4A larger than the single primary knock-on theory predicts. A is the ratio of the atomic mass to the neutron mass. The importance of this result to the theory of neutron sputtering is explained. (orig.) [de

  14. Method for simultaneous measurement of borehole and formation neutron decay-times

    International Nuclear Information System (INIS)

    Smith, H.D.; Arnold, D.M.

    1982-01-01

    A method is described of making in situ measurements of the thermal neutron decay time of earth formations in the vicinity of a wellbore. The borehole and earth formations are irradiated, with pulsed fast neutrons and, during the interval between neutron pulses, capture gamma radiation is measured in at least four, non-overlapping, contiguous time intervals. Count-rates representative of thermal neutron populations in the borehole and the formations are made during each of the time intervals. A background radiation measurement for correcting the count-rates is preferably also periodically made. The count-rates are combined to derive simultaneously the formation and borehole neutron lifetime components which are recorded as a function of borehole depth. (author)

  15. Beta-delayed neutron decay of $^{33}$Na

    CERN Document Server

    Radivojevic, Z; Caurier, E; Cederkäll, J; Courtin, S; Dessagne, P; Jokinen, A; Knipper, A; Le Scornet, G; Lyapin, V G; Miehé, C; Nowacki, F; Nummela, S; Oinonen, M; Poirier, E; Ramdhane, M; Trzaska, W H; Walter, G; Äystö, J

    2002-01-01

    Beta-delayed neutron decay of /sup 33/Na has been studied using the on-line mass separator ISOLDE. The delayed neutron spectra were measured by time-of-flight technique using fast scintillators. Two main neutron groups at 800(60) and 1020(80) keV were assigned to the /sup 33/Na decay, showing evidence for strong feeding of states at about 4 MeV in /sup 33/Mg. By simultaneous beta - gamma -n counting the delayed neutron emission probabilities P/sub 1n/ = 47(6)% and P /sub 2n/ = 13(3)% were determined. The half-life value for /sup 33 /Na, T/sub 1/2/ = 8.0(3) ms, was measured by three different techniques, one employing identifying gamma transitions and two employing beta and neutron counting. (21 refs).

  16. On the Proton Spectrum in Free Neutron beta-decay

    CERN Document Server

    Bunatian, G G

    2000-01-01

    We consider the calculations which are appropriate to acquire with a high precision, of ~1% or better, the general characteristics of weak interactions from the experiments on the free neutron beta-decay; the principle emphasis is placed on the phenomena associated with the recoil of protons. The part played by electromagnetic interactions in beta-decay is visualized, with special attention drawn to the influence of the gamma-radiation on the momentum distribution of the particles in the final state. The effect of electromagnetic interactions on the proton recoil spectrum is studied, in the light of the experiments which are carried out and planned for now. The results of the calculations, which are to be confronted with the experimental data, are presented upright in terms of the effective Lagrangian underlying the inquiry. Owing to electromagnetic interactions, the corrections to the energy distribution of protons prove to amount to the value of a few per cent. Nowadays, this is substantial to obtain with a...

  17. LHCb: Radiative Decays at LHCb

    CERN Multimedia

    Teodorescu, E

    2011-01-01

    The decay modes $B_d\\to K^*\\gamma$ and $B_s \\to \\phi \\gamma$ are promising laboratories for the search of New Physics effects, their properties being particularly sensitive to the presence of new heavy particles that may propagate virtually within the one-loop process involved in penguin diagrams. The penguin $B_s \\to \\phi \\gamma$ decay has been observed by Belle with rather poor precision, $\\mathcal{B}$($B_s \\to \\phi \\gamma$) = 57$^{+22}_{-19}$ x 10$^{-6}$, therefore, additional measurements are expected for this channel. With a data sample corresponding to an integrated luminosity of ~36 pb$^{-1}$ collected in 2010, a clear and promising signal has been observed for the $B_d\\to K^*\\gamma$. The mass resolution is dominated by the electromagnetic calorimeter energy resolution (ECAL is inter-calibrated at the ~2% level). A first hint of the $B_s \\to \\Phi \\gamma$  decay has also been observed. Given this preliminary results and the theory predictions, we expect that, with the data we will record in 2011, th...

  18. The direct neutron decay of giant resonances in 208Pb

    International Nuclear Information System (INIS)

    Bracco, A.

    1988-01-01

    The neutron decay of the giant multipole resonance region from 9 to 15 MeV of excitation energy in 208 Pb has been studied. Neutron branching ratios for the decay to the ground state and to the low-lying excited states of 207 Pb were measured as a function of the excitation energy of 208 Pb and compared to Hauser-Feshbach calculations. While the neutron branching ratios from the energy region of the isoscalar giant quadrupole resonance are reproduced by the calculations, the ratios from the energy region of the isoscalar giant monopole resonance show a conspicuous excess with respect to the statistical model predictions. The neutron yield from this energy region was analysed in terms of a multistep model of the compound nucleus which includes collective doorway channels. The total direct escape width as well as the associated direct partial escape widths to the lowest five valence hole states of 207 Pb were determined. (orig.)

  19. Dark Matter Interpretation of the Neutron Decay Anomaly.

    Science.gov (United States)

    Fornal, Bartosz; Grinstein, Benjamín

    2018-05-11

    There is a long-standing discrepancy between the neutron lifetime measured in beam and bottle experiments. We propose to explain this anomaly by a dark decay channel for the neutron, involving one or more dark sector particles in the final state. If any of these particles are stable, they can be the dark matter. We construct representative particle physics models consistent with all experimental constraints.

  20. Dark Matter Interpretation of the Neutron Decay Anomaly.

    OpenAIRE

    Fornal, B; Grinstein, B

    2018-01-01

    There is a long-standing discrepancy between the neutron lifetime measured in beam and bottle experiments. We propose to explain this anomaly by a dark decay channel for the neutron, involving one or more dark sector particles in the final state. If any of these particles are stable, they can be the dark matter. We construct representative particle physics models consistent with all experimental constraints.

  1. Decay properties of some neutron-rich praseodymium isotopes

    International Nuclear Information System (INIS)

    Skarnemark, G.; Aronsson, P.O.; Stender, E.; Trautmann, N.; Kaffrell, N.; Bjoernstad, T.; Kvale, E.; Skarestad, M.

    1976-01-01

    Neutron-rich Pr isotopes produced in the thermal neutron-induced fission of 235 U have been investigated by means of γ-γ coincidence experiments. The nuclides have been separated from the fission product mixture, using the fast chemical separation system SISAK in connection with a gas jet recoil transport system. The results include assignments of several new γ-ray energies and partial decay schemes for 147 Pr, 148 Pr, 149 Pr and 150 Pr. (orig.) [de

  2. Dark Matter Interpretation of the Neutron Decay Anomaly

    OpenAIRE

    Fornal, Bartosz; Grinstein, Benjamín

    2018-01-01

    There is a long-standing discrepancy between the neutron lifetime measured in beam and bottle experiments. We propose to explain this anomaly by a dark decay channel for the neutron, involving one or more dark sector particles in the final state. If any of these particles are stable, they can be the dark matter. We construct representative particle physics models consistent with all experimental constraints.

  3. Dark Matter Interpretation of the Neutron Decay Anomaly

    Science.gov (United States)

    Fornal, Bartosz; Grinstein, Benjamín

    2018-05-01

    There is a long-standing discrepancy between the neutron lifetime measured in beam and bottle experiments. We propose to explain this anomaly by a dark decay channel for the neutron, involving one or more dark sector particles in the final state. If any of these particles are stable, they can be the dark matter. We construct representative particle physics models consistent with all experimental constraints.

  4. Measurement of Angular Correlations in the Decay of Polarized Neutrons

    DEFF Research Database (Denmark)

    Christensen, Carl Jørgen; Krohn, V.E.; Ringo, G.R.

    1970-01-01

    The electron-momentum-neutron-spin correlation coefficient was found to be A=-0.115±0.008, and the antineutrino-momentum-neutron-spin correlation coefficient was found to be B=1.00±0.05. The value of A leads to |GA/GV|=1.26±0.02 for the ratio of Gamow-Teller-to-Fermi coupling constants in β decay...

  5. Radiative decays of B mesons at LHCb

    CERN Document Server

    Soomro, Fatima; Golutvin, Andrei

    2011-01-01

    This thesis is dedicated to the study of radiative decays of $B$ mesons at LHC$b$. At quark level, such decays are a $b\\to s\\gamma$ transition and take place via a penguin loop and are sensitive to virtual contribution of New Physics, which can be indicated by an increase in the decay rates. These decays also offer the possibility to test the V-A structure of the Standard Model coupling in the processes mediated by loop penguin diagrams. In the decay $B_s \\to \\phi\\gamma$, New Physics contribution can be probed by measuring the polarization of the photon in this decay. Systematic effects in the proper time reconstruction of the $B_s$ in $B_s \\to \\phi\\gamma$ can bias the photon polarization measurement in this decay, which will reduce the sensitivity on the relevant New Physics parameter. The author studied those effects and developed ideas to calibrate them using $B_d\\to K^{*}\\gamma$ and $B_s\\to J/\\psi\\phi$ decays as control channels. These studies are mostly Monte Carlo based due to a relatively small data ...

  6. Radiative Ke3 decays revisited

    International Nuclear Information System (INIS)

    Gasser, J.; Kubis, B.; Paver, N.; Verbeni, M.

    2005-01-01

    Motivated by recent experimental results and ongoing measurements, we review the chiral perturbation theory prediction for K L →π -+ e ± ν e γ decays. Special emphasis is given to the stability of the inner bremsstrahlung-dominated relative branching ratio versus the K e3 form factors, and on the separation of the structure-dependent amplitude in differential distributions over the phase space. For the structure-dependent terms, an assessment of the order p 6 corrections is given, in particular, a full next-to-leading order calculation of the axial component is performed. The experimental analysis of the photon energy spectrum is discussed, and other potentially useful distributions are introduced. (orig.)

  7. Scalar mesons and radiative vector meson decays

    International Nuclear Information System (INIS)

    Gokalp, A.; Ylmaz, O

    2002-01-01

    The light scalar mesons with vacuum quantum numbers J p =0 ++ have fundamental importance in understanding low energy QCD phenomenology and the symmetry breaking mechanisms in QCD. The nature and quark substructure of the best known scalar mesons, isoscalar σ(500), f0(980) and isovector a0(980) have been a subject of continuous controversy. The radioactive decay of neutral vector mesons ρ, w and φ into a single photon and a pair of neutral pseudoscalar mesons have been studied in order to obtain information on the nature of these scalar mesons. For such studies, it is essential that a reliable understanding of the mechanisms for these decays should be at hand. In this work, we investigate the particularly interesting mechanism of the exchange of scalar mesons for the radiative vector meson decays by analysing the experimental results such as measured decay rates and invariant mass spectra and compare them with the theoretical prediction of different reaction mechanisms

  8. Overlapping β decay and resonance neutron spectroscopy

    International Nuclear Information System (INIS)

    Raman, S.; Fogelberg, B.

    1984-01-01

    By carrying out a detailed study of 87 Kr levels, we have shown that delayed neutron spectroscopy can be a viable method for studying individual levels and that a broad resonance-like structure is present in the β-strength distribution. 12 refs., 1 fig

  9. Decay Studies of Very Neutron Rich Nuclei near 78Ni

    International Nuclear Information System (INIS)

    Winger, J. A.; Ilyushkin, S.; Korgul, A.; Gross, Carl J; Rykaczewski, Krzysztof Piotr; Batchelder, J. C.; Goodin, C.; Grzywacz, R.; Hamilton, J. H.; Krolas, W.; Liddick, Sean; Mazzocchi, C.; Nelson, C.; Padgett, Stephen; Piechaczek, A.; Rajabali, M. M.; Shapira, Dan; Zganjar, E. F.

    2008-01-01

    The properties of beta-gamma and beta-delayed neutron emission from 76-79 Cu and 83-85 Ga were measured at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. Selected results on the decay properties of copper isotopes are briefly presented and discussed

  10. Study of $\\beta$-delayed neutron decay of $^{8}$He

    CERN Multimedia

    The goal of the present proposal is to study $\\beta$-delayed neutron decay branch of $^{8}$He. The energy spectra of the emitted neutrons will be measured in the energy range of 0.1 – 6 MeV using the VANDLE spectrometer. Using coincident $\\gamma$-ray measurement, components of the spectrum corresponding to transitions to the ground- and first- excited states of $^{7}$Li will be disentangled. The new data will allow us to get a more complete picture of the $\\beta$-decay of $^{8}$He and to clarify the discrepancy between the B(GT) distributions derived from the $\\beta$-decay and $^{8}$He(p, n)$^{8}$Li reaction studies.

  11. Simultaneous thermal neutron decay time and porosity logging system

    International Nuclear Information System (INIS)

    Shultz, W.E.

    1980-01-01

    A method for simultaneously determining the porosity and thermal neutron capture cross-section of earth formations in the vicinity of a well borehole is claimed. It comprises the following steps: passing a well tool into a cased well borehole. The tool has a pulsed source of fast neutrons, a combination fast neutron and gamma ray detector and an epithermal neutron detector; repetitively irradiating the earth formations in the vicinity of the borehole with bursts of fast neutrons; detecting the fast neutron and epithermal neutron populations in the borehole (during the neutron bursts) and generating first and second measurement signals; detecting for second and third time intervals during the time between the neutron bursts, the gamma radiation present in the borehole due to the capture of thermalized neutrons by the nuclei of elements comprising the earth formations and generating third and fourth measurement signals; and combining the first and second measurement signals according to a predetermined relationship to derive an indication of the porosity of the earth formations and combining the third and fourth measurement signals to derive an indication of the thermal neutron capture cross-section of the earth formations

  12. Correction factor for the experimental prompt neutron decay constant

    International Nuclear Information System (INIS)

    Talamo, Alberto; Gohar, Y.; Sadovich, S.; Kiyavitskaya, H.; Bournos, V.; Fokov, Y.; Routkovskaya, C.

    2013-01-01

    Highlights: • Definition of a spatial correction factor for the experimental prompt neutron decay constant. • Introduction of a MCNP6 calculation methodology to simulate Rossi-alpha distribution for pulsed neutron sources. • Comparison of MCNP6 results with experimental data for count rate, Rossi-alpha, and Feynman-alpha distributions. • Improvement of the comparison between numerical and experimental results by taking into account the dead-time effect. - Abstract: This study introduces a new correction factor to obtain the experimental effective multiplication factor of subcritical assemblies by the point kinetics formulation. The correction factor is defined as the ratio between the MCNP6 prompt neutron decay constant obtained in criticality mode and the one obtained in source mode. The correction factor mainly takes into account the longer neutron lifetime in the reflector region and the effects of the external neutron source. For the YALINA Thermal facility, the comparison between the experimental and computational effective multiplication factors noticeably improves after the application of the correction factor. The accuracy of the MCNP6 computational model of the YALINA Thermal subcritical assembly has been verified by reproducing the neutron count rate, Rossi-α, and Feynman-α distributions obtained from the experimental data

  13. Radiative decay of light and heavy mesons

    International Nuclear Information System (INIS)

    Barik, N.; Dash, P.C.

    1994-01-01

    The M1 transition among the vector (V) and pseudoscalar (P) mesons in the light and heavy flavor sectors has been investigated in a potential model of independent quarks. Going beyond the static approximation, to add some momentum dependence due to the recoil effect in a more realistic calculation, we find an improvement in the results for the radiative decay of light flavored mesons. However, our prediction on the decay rates for the mesons (D * and B * ) in the heavy flavor sector remains unaffected and compares well with those of other model calculations

  14. Study of the radiative pion decay

    International Nuclear Information System (INIS)

    Chen, Chuan-Hung; Geng, Chao-Qiang; Lih, Chong-Chung

    2011-01-01

    We study the radiative pion decay of π + →e + ν e γ in the light-front quark model. We also summarize the result in the chiral perturbation theory. The vector and axial-vector hadronic form factors (F V,A ) for the π→γ transition are evaluated in the whole allowed momentum transfer. In terms of these momentum dependent form factors, we calculate the decay branching ratio and compare our results with the experimental data and other theoretical predictions in the literature. We also constrain the possible size of the tensor interaction in the light-front quark model.

  15. Lepton radiative decays in supersymmetric standard model

    International Nuclear Information System (INIS)

    Volkov, G.G.; Liparteliani, A.G.

    1988-01-01

    Radiative decays of charged leptons l i →l j γ(γ * ) have been discussed in the framework of the supersymmetric generalization of the standard model. The most general form of the formfactors for the one-loop vertex function is written. Decay widths of the mentioned radiative decays are calculated. Scalar lepton masses are estimated at the maximal mixing angle in the scalar sector proceeding from the present upper limit for the branching of the decay μ→eγ. In case of the maximal mixing angle and the least mass degeneration of scalar leptons of various generations the following lower limit for the scalar electron mass m e-tilde >1.5 TeV has been obtained. The mass of the scalar neutrino is 0(1) TeV, in case the charged calibrino is lighter than the scalar neutrino. The result obtained sensitive to the choice of the lepton mixing angle in the scalar sector, namely, in decreasing the value sin 2 θ by an order of magnitude, the limitation on the scalar electron mass may decrease more than 3 times. In the latter case the direct observation of electrons at the e + e - -collider (1x1 TeV) becomes available

  16. A New Approach to Measuring the Neutron Decay Correlations with Cold Neutrons at LANSCE

    International Nuclear Information System (INIS)

    Wilburn, W.S.; Bowman, J.D.; Greene, G.L.; Jones, G.L.; Kapustinsky, J.S.; Penttila, S.I.

    1999-01-01

    Precision measurements of the neutron beta-decay correlations A, B, a, and b provide important tests of the standard model of electroweak interactions: a test of the unitarity of the first row of the CKM matrix, a search for new weak interactions, a test of the theory of nuclear beta decays, and a test of the conserved-vector-current hypothesis. The authors are designing an experiment at the LANSCE short-pulse spallation source to measure all four correlations to an order of magnitude better accuracy than the existing measurements. The accuracy of the previous measurements was limited by systematics. The design of the proposed experiment makes use of the pulsed nature of the LANSCE source to reduce systematic errors associated with the measurement of the neutron polarization as well as other systematic errors. In addition, the authors are developing silicon strip detectors for detecting both the proton and electron from the neutron decay

  17. T-odd momentum correlation in radiative {beta} decay

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, Susan, E-mail: gardner@pa.uky.edu; He, Daheng [University of Kentucky, Department of Physics and Astronomy (United States)

    2013-03-15

    The triple-product correlations observable in ordinary neutron or nuclear beta decay are all naively T violating and can connect, through an assumption of CPT invariance, to constraints on sources of CP violation beyond the Standard Model. They are also spin dependent. In this context the study of radiative beta decay opens a new possibility, in that a triple-product correlation can be constructed from momenta alone. Consequently its measurement would constrain new spin-independent sources of CP violation. We will describe these in light of the size of the triple momentum correlation in the decay rate arising from electromagnetic final-state interactions in the Standard Model. Our expression for the corresponding T-odd asymmetry is exact in O({alpha}) up to terms of recoil order, and we evaluate it numerically under various kinematic conditions. We consider the pattern of the asymmetries in nuclear {beta} decays and show that the asymmetry can be suppressed in particular cases, facilitating searches for new sources of CP violation in such processes.

  18. Time reversal invariance - a test in free neutron decay

    Energy Technology Data Exchange (ETDEWEB)

    Lising, Laura Jean [Univ. of California, Berkeley, CA (United States)

    1999-01-01

    Time reversal invariance violation plays only a small role in the Standard Model, and the existence of a T-violating effect above the predicted level would be an indication of new physics. A sensitive probe of this symmetry in the weak interaction is the measurement of the T-violating ''D''-correlation in the decay of free neutrons. The triple-correlation Dσn∙pe x pv involves three kinematic variables, the neutron spin, electron momentu, and neutrino (or proton) momentum, and changes sign under time reversal. This experiment detects the decay products of a polarized cold neutron beam with an octagonal array of scintillation and solid-state detectors. Data from first run at NIST's Cold Neutron Research Facility give a D-coefficient of -0.1 ± 1.3(stat.) ± 0.7(syst) x 10-3 This measurement has the greatest bearing on extensions to the Standard model that incorporate leptoquarks, although exotic fermion and lift-right symmetric models also allow a D as large as the present limit.

  19. Method and apparatus for epithermal neutron decay logging

    International Nuclear Information System (INIS)

    Nelligan, W.B.

    1998-01-01

    The nature of hydrogenous fluids filling the pore spaces in formations surrounding a well bore are determined by irradiating the formations with bursts of high energy neutrons and using the ratio of time-dependent parameters related to the decay of epithermal neutron populations above two different energy levels to provide values indicative of the kind of fluid present, independent of porosity. The measurement above the higher of these energy levels, appr. 0.4eV, indicates the existence of hydrogenous fluid, water and hydrocarbons in the formations. The lower threshold measurement, above appr. 0.15eV, is indicative of the structure of the molecule in which the hydrogen molecule is bound and of the porosity. A pulsed neutron generator in a sonde irradiates the formations with 14meV neutrons and a pair of detectors, one shielded by cadmium, to establish the 0.4eV threshold energy level and the other, shielded by gadolinium, to establish the 0.15eV threshold energy level. Time related parameters of the count rate information, e.g. the decay constants, provided by each detector are derived. The ratio of the respective parameters is used to identify the type of fluid in the information, independent of porosity. The method and apparatus can determine water saturation, i.e. percentage of water in the formation fluid and can identify specific types of hydrocarbons under 100% hydrocarbon saturation conditions. 8 figs

  20. Influence Of The Neutron Richness On Binary Decays

    Directory of Open Access Journals (Sweden)

    Roy R.

    2010-03-01

    Full Text Available The influence of the neutron richness on binary decays is investigated in 78,82Kr+ 40Ca reactions at 5.5 MeV/A incident energy. Kinetic energy distributions and angular distributions of fragments with atomic number 6 ≤ Z ≤ 28 were measured using the 4π-INDRA array. Global features are compatible with an emission from a long-lived system. The yields around the symmetric splitting are about 30The persistence of strong structural effects is evidenced from elemental cross-sections of the light fragments. The cross-sections for odd-Z fragments are higher for the neutron rich CN while cross-sections for even-Z fragments are higher for the neutron poor CN. Calculations assuming two different potential energy surfaces are presented.

  1. Radiation safety of soil moisture neutron probes

    International Nuclear Information System (INIS)

    Oresegun, M.O.

    2000-01-01

    The neutron probe measures sub-surface moisture in soil and other materials by means of high energy neutrons and a slow (thermal) neutron detector. Exposure to radiation, including neutrons, especially at high doses, can cause detrimental health effects. In order to achieve operational radiation safety, there must be compliance with protection and safety standards. The design and manufacture of commercially available neutron moisture gauges are such that risks to the health of the user have been greatly reduced. The major concern is radiation escape from the soil during measurement, especially under dry conditions and when the radius of influence is large. With appropriate work practices as well as good design and manufacture of gauges, recorded occupational doses have been well below recommended annual limits. It can be concluded that the use of neutron gauges poses not only acceptable health and safety risks but, in fact, the risks are negligible. Neutron gauges should not be classified as posing high potential health hazards. (author)

  2. Radiative corrections in K→3π decays

    International Nuclear Information System (INIS)

    Bissegger, M.; Fuhrer, A.; Gasser, J.; Kubis, B.; Rusetsky, A.

    2009-01-01

    We investigate radiative corrections to K→3π decays. In particular, we extend the non-relativistic framework developed recently to include real and virtual photons and show that, in a well-defined power counting scheme, the results reproduce corrections obtained in the relativistic calculation. Real photons are included exactly, beyond the soft-photon approximation, and we compare the result with the latter. The singularities generated by pionium near threshold are investigated, and a region is identified where standard perturbation theory in the fine structure constant α may be applied. We expect that the formulae provided allow one to extract S-wave ππ scattering lengths from the cusp effect in these decays with high precision

  3. Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

    Energy Technology Data Exchange (ETDEWEB)

    Scott Wilde, Raymond Keegan

    2008-07-01

    The countrate response of a gamma spectrometry system from a neutron radiation source behind a plane of moderating material doped with a nuclide of a large radiative neutron capture cross-section exhibits a countrate response analogous to a gamma radiation source at the same position from the detector. Using a planar, surface area of the neutron moderating material exposed to the neutron radiation produces a larger area under the prompt gamma ray peak in the detector than a smaller area of dimensions relative to the active volume of the gamma detection system.

  4. Neutron spectroscopy, nuclear structure, related topics. Abstracts

    International Nuclear Information System (INIS)

    Sukhovoj, A.M.

    1996-01-01

    Neutron spectroscopy, nuclear structure and related topics are considered. P, T-breaking, neutron beta decay, neutron radiative capture and neutron polarizability are discussed. Reaction with fast neutrons, methodical aspect low-energy fission are considered too

  5. Fast Neutron Radiation Effects on Bacillus Subtili

    International Nuclear Information System (INIS)

    Chen Xiaoming; Zhang Jianguo; Chu Shijin; Ren Zhenglong; Zheng Chun; Yang Chengde; Tan Bisheng

    2009-01-01

    To examine the sterilizing effect and mechanism of neutron radiation, Bacillus subtilis var. niger. strain (ATCC 9372) spores were irradiated with the fast neutron from the Chinese fast burst reactor II(CFBR-II). The plate-count results indicated that the D 10 value was 384.6 Gy with a neutron radiation dose rate of 7.4 Gy/min. The rudimental catalase activity of the spores declined obviously with the increase in the radiation dose. Meanwhile, under the scanning electron microscope, no visible influence of the neutron radiation on the spore configuration was detected even if the dose was increased to 4 kGy. The content and distribution of DNA double-strand breaks induced by neutron radiation at different doses were measured and quantified by pulsed-field gel electrophoresis (PFGE). Further analysis of the DNA release percentage (PR), the DNA breakage level (L), and the average molecular weight, indicated that DNA fragments were obviously distributed around the 5 kb regions at different radiation doses, which suggests that some points in the DNA molecule were sensitive to neutron radiation. Both PR and L varied regularly to some extent with the increase in radiation dose. Thus neutron radiation has a high sterilization power, and can induce falling enzyme activity and DNA breakage in Bacillus subtilis spores

  6. Strong Neutron-γ Competition above the Neutron Threshold in the Decay of ^{70}Co.

    Science.gov (United States)

    Spyrou, A; Liddick, S N; Naqvi, F; Crider, B P; Dombos, A C; Bleuel, D L; Brown, B A; Couture, A; Crespo Campo, L; Guttormsen, M; Larsen, A C; Lewis, R; Möller, P; Mosby, S; Mumpower, M R; Perdikakis, G; Prokop, C J; Renstrøm, T; Siem, S; Quinn, S J; Valenta, S

    2016-09-30

    The β-decay intensity of ^{70}Co was measured for the first time using the technique of total absorption spectroscopy. The large β-decay Q value [12.3(3) MeV] offers a rare opportunity to study β-decay properties in a broad energy range. Two surprising features were observed in the experimental results, namely, the large fragmentation of the β intensity at high energies, as well as the strong competition between γ rays and neutrons, up to more than 2 MeV above the neutron-separation energy. The data are compared to two theoretical calculations: the shell model and the quasiparticle random phase approximation (QRPA). Both models seem to be missing a significant strength at high excitation energies. Possible interpretations of this discrepancy are discussed. The shell model is used for a detailed nuclear structure interpretation and helps to explain the observed γ-neutron competition. The comparison to the QRPA calculations is done as a means to test a model that provides global β-decay properties for astrophysical calculations. Our work demonstrates the importance of performing detailed comparisons to experimental results, beyond the simple half-life comparisons. A realistic and robust description of the β-decay intensity is crucial for our understanding of nuclear structure as well as of r-process nucleosynthesis.

  7. High energy radiation from neutron stars

    International Nuclear Information System (INIS)

    Ruderman, M.

    1985-04-01

    Topics covered include young rapidly spinning pulsars; static gaps in outer magnetospheres; dynamic gaps in pulsar outer magnetospheres; pulse structure of energetic radiation sustained by outer gap pair production; outer gap radiation, Crab pulsar; outer gap radiation, the Vela pulsar; radioemission; and high energy radiation during the accretion spin-up of older neutron stars. 26 refs., 10 figs

  8. Competition of neutrino and gravitational radiation in neutron star formation

    International Nuclear Information System (INIS)

    Kazanas, D.; Schramm, D.N.

    1976-01-01

    The possibility is explored that neutrino radiation, rather than gravitational radiation, may be the dominant way by which non-radial pulsations are damped out in a collapsing star. If this is so it implies that hopes of detecting gravity waves from supernovae explosions are very optimistic. Neutron stars and black holes are probably the collapsed central remnants of a supernovae explosion. These objects presumably originate from collapse of the cores of sufficiently massive stars, following the cessation of thermonuclear burning. Although there is at present no completely consistent detailed theory as to how collapse of the core and the subsequent supernova explosion take place, a general model exists for the final stages of stellar evolution and supernovae explosions. According to this model the electrons of a sufficiently massive stellar core, due to the high density and temperature, become absorbed by the protons through the reaction p + e - → n + v. Very large numbers of neutrinos, resulting from this and other thermal processes, such as pair annihilation, plasma decay, and Bremsstrahlung, are emitted, taking away most of the gravitational energy of the collapse. These neutrinos possibly drive ejection of the overlying stellar mantle, whilst the neutron-rich core collapses further to a condensed remnant. Gravitational radiation comes into play only at very late stages of the collapse. All of this implies that neutrino radiation might contribute to the decay of the non-radial oscillations of the collapsing core and the newly formed neutron star, possibly damping out these oscillations much faster than gravitational radiation. In order to obtain a more quantitative answer to the question the effects of neutrino radiation on the non-radial oscillations are examined. The implication is that neutrino radiation, by more rapid damping of the non-radial oscillations of a newly formed neutron star in a supernova explosion, would hinder gravitational radiation and

  9. Assessment of radiation fields from neutron irradiated structural components of the 40 MW research reactor CIRUS

    International Nuclear Information System (INIS)

    Sankaranarayanan, S.; Sharma, S.K.

    1993-01-01

    The paper summarizes the results of an assessment of the radiation fields from the long-lived neutron activation products (including the decay chain products) in the various structural components of the CIRUS reactor. Special attention is given for the analysis of neutron activation of impurity elements present in the materials of the structure. 16 refs, 4 figs, 4 tabs

  10. Level gauge using neutron radiation

    International Nuclear Information System (INIS)

    Mathew, P.J.

    1985-01-01

    Apparatus for determining the level of a solid or liquid material in a container comprises: a vertical guide within or alongside the container; a sensor positioned within the guide; means for moving the sensor along the guide; and means for monitoring the position of the sensor. The sensor comprises a source of fast neutrons, a detector for thermal neutrons, and a body of a neutron moderating material in close proximity to the detector. Thermal neutrons produced by fast neutron irradiation of the solid or liquid material, or thermal neutrons produced by irradiation of the neutron-moderating material by fast or epithermal neutrons reflected by the solid or liquid material, are detected when the sensor is positioned at or below the level of the material in the container

  11. Inclusive radiative J/ψ decays

    International Nuclear Information System (INIS)

    Besson, D.; Pedlar, T. K.; Cronin-Hennessy, D.; Gao, K. Y.; Hietala, J.; Kubota, Y.; Klein, T.; Lang, B. W.; Poling, R.; Scott, A. W.; Zweber, P.; Dobbs, S.; Metreveli, Z.; Seth, K. K.; Tomaradze, A.; Libby, J.; Powell, A.; Wilkinson, G.; Ecklund, K. M.; Love, W.

    2008-01-01

    Using data taken with the CLEO-c detector at the Cornell Electron Storage Ring, we have investigated the direct-photon momentum spectrum in the decay J/ψ(1S)→γgg, via the ''tagged'' process: e + e - →ψ(2S); ψ(2S)→J/ψπ + π - ; J/ψ→γ+X. Including contributions from two-body radiative decay processes, we find the ratio of the inclusive direct-photon branching fraction to that of the dominant three-gluon branching fraction [R γ =B(ggγ)/B(ggg)] to be R γ =0.137±0.001±0.016±0.004, where the errors shown are statistical, systematic, and the model-dependent uncertainty related to the extrapolation to zero photon energy. The shape of the scaled photon energy spectrum in J/ψ→ggγ is observed to be very similar to that of Υ→ggγ. The R γ value obtained is roughly consistent with that expected by a simple quark-charge scaling [R γ ∼(q c /q b ) 2 ] of the value determined at the Υ(1S), but somewhat higher than the value expected from the running of the strong coupling constant.

  12. Exclusive rare radiative decays of B mesons

    International Nuclear Information System (INIS)

    Barik, N.; Kar, S.; Dash, P.C.

    1998-01-01

    The exclusive rare radiative B decays are studied in the relativistic independent quark model based on the confining potential in the scalar-vector harmonic form. The relevant form factors as well as the branching ratios for the processes B 0 →K *0 γ and B ± →K *± γ have been estimated in reasonable agreement with the available experimental data. The result compares well with several other model predictions. The calculation has been extended to the CKM-favored process B s →φγ and CKM-suppressed processes B u,d →ργ and B s →K * γ. copyright 1997 The American Physical Society

  13. Radiative decays of single heavy flavour baryons

    International Nuclear Information System (INIS)

    Majethiya, Ajay; Patel, Bhavin; Vinodkumar, P.C.

    2009-01-01

    The electromagnetic transitions between (J P =(3)/(2) + ) and (J P =(1)/(2) + ) baryons are important decay modes to observe new hadronic states experimentally. For the estimation of these transitions widths, we employ a non-relativistic quark potential model description with color Coulomb plus linear confinement potential. Such a description has been employed to compute the ground-state masses and magnetic moments of the single heavy flavor baryons. The magnetic moments of the baryons are obtained using the spin-flavor structure of the constituting quark composition of the baryon. Here, we also define an effective constituent mass of the quarks (ecqm) by taking into account the binding effects of the quarks within the baryon. The radiative transition widths are computed in terms of the magnetic moments of the baryon and the photon energy. Our results are compared with other theoretical models. (orig.)

  14. Radiative β-decay in 141Ce

    International Nuclear Information System (INIS)

    Rao, K.S.G.; Sanjeeviah, H.

    1982-01-01

    The spectral distribution of the continuous gamma radiation accompanying non-unique first forbidden β-decay of 32 d 141 Ce has been measured in the energy range 200-560 keV with a 4.5 cm x 5.08 cm NaI(Tl) scintillation spectrometer. The source electrons were eliminated using an electromagnet. The raw spectrum was corrected for pile-up, finite energy resolution, Compton electron distribution and geometrical γ-detection efficiency using the method of Liden and Starfelt. The corrected distribution is compared with the direct and detour theories of Lewis and Ford, and Ford and Martin, respectively. Total disagreement between experiment and theory was observed over the entire region of the investigated spectrum. In the energy region from 200 to 350 keV, however, the measured spectrum lies between the direct and detour theories. (orig.)

  15. Method and apparatus for neutron radiation monitoring

    International Nuclear Information System (INIS)

    Schwarzmann, A.

    1985-01-01

    A self-calibrated neutron radiation monitor includes a flux responsive element comprised of intrinsic silicon neutron detectors and self-calibration resistors in a single structure. As the resistance of the flux responsive element increases to the value of successive calibration resistors, known increments of flux have been encountered

  16. Decay studies of the highly neutron-deficient indium isotopes

    International Nuclear Information System (INIS)

    Wouters, J.M.

    1982-02-01

    An extension of the experimentally known nuclidic mass surface to nuclei far from the region of beta-stability is of fundamental interest in providing a better determination of the input parameters for the various nuclear mass formulae, allowing a more accurate prediction of the ultimate limits of nuclear stability. In addition, a study of the shape of the mass surface in the vicinity of the doubly-closed nuclide 100 Sn provides initial information on the behavior of the shell closure to be expected when Z = N = 50. Experiments measuring the decay energies of 103 105 In by β-endpoint measurements are described with special attention focused on the development of a plastic scintillator β-telescope coupled to the on-line mass separator RAMA (Recoil Atom Mass Analyzer). An attempt to measure the β-endpoint energy of 102 In is also briefly described. The experimentally determined decay energies and derived masses for 103 105 In are compared with the predictions of different mass models to identify which models are more successful in this region. Furthermore, the inclusion in these comparisons of the available data on the neutron-rich indium nuclei permits a systematic study of their ground state mass behavior as a function of the neutron number between the shell closures at N = 50 and N = 82. These analyses indicate that the binding energy of 103 In is 1 MeV larger than predicted by the majority of the mass models. An examination of the Q/sub EC/ surface and the single- and two-neutron separation energies in the vicinity of 103 105 In is also performed to investigate further the deviation and other possible systematic variations in the mass surface in a model-independent way

  17. J/psi and Υ radiative and hadronic decays

    International Nuclear Information System (INIS)

    Bloom, E.D.

    1987-07-01

    The search for gluonium at the J/psi and Υ is discussed, as well as the search for exotics at the Υ. Reactions discussed include radiative and hadronic decays of the J/psi and the search for radiative decays of the Υ. Future perspectives are also briefly considered. 45 refs., 27 figs

  18. Neutronics methods for thermal radiative transfer

    International Nuclear Information System (INIS)

    Larsen, E.W.

    1988-01-01

    The equations of thermal radiative transfer are time discretized in a semi-implicit manner, yielding a linear transport problem for each time step. The governing equation in this problem has the form of a neutron transport equation with fission but no scattering. Numerical methods are described, whose origins lie in neutron transport, and that have been successfully adapted to this new problem. Acceleration methods that have been developed specifically for the radiative transfer problem, but may have generalizations applicable in neutronics problems, are also discussed

  19. Radiative Decays of the B Meson

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Hirohisa A

    2003-09-23

    The radiative decays of the B meson to the final states K *(892){gamma} and {rho}(770){gamma} proceed through virtual effective flavor-changing neutral current processes which are sensitive to contributions from high mass scales from within the Standard Model of particle interactions and from possible new physics. In the context of the Standard Model, these transitions are of interest in probing the weak interaction behavior of the top quark. In particular, the ratio of branching fractions for the two processes can be used to extract the ratio of Cabibbo-Kobayashi-Maskawa matrix elements |V{sub td}/V{sub ts}|. Potential new physics contributions in these virtual transitions may induce new sources of direct CP violation and enhancement or suppression of the rate of these processes. The B {yields} K*{gamma} is a manifestation of the b {yields} s{gamma} radiative transition. This process has been previously observed by the CLEO collaboration and its branching fraction measured. While the theoretical prediction for the inclusive rate of b {yields} s{gamma} transitions is more robust than that of the exclusive B {yields} K*{gamma}, the prospects for precise measurements of {Beta}[B {yields} K*{gamma}] and direct CP violation in this channel has attracted considerable attention. The analysis described here represents an improved measurement of the B {yields} K*{gamma} branching factions and a more sensitive search for direct CP violation. In 22.7 x 10{sup 6} B{bar B} events collected by the BABAR detector in 1999-2000, we measure: {Beta}[B{sup 0} {yields} K*{sup 0}{gamma}] = 4.23 {+-} 0.40(stat.) {+-} 0.22(syst.) x 10{sup -5} and {Beta}[B{sup +} {yields} K*{sup +}{gamma}] = 3.83 {+-} 0.62(stat.) {+-} 0.22(syst.) x 10{sup -5}. We find no evidence for direct CP violation in the decays and constrain -0.170 < A{sub CP} < 0.082 at 90% Confidence Level. The B {yields} {rho}{gamma} proceeds through the analogous b {yields} d{gamma} radiative transition. As such, its rate is

  20. Beta decay rates of neutron-rich nuclei

    Science.gov (United States)

    Marketin, Tomislav; Huther, Lutz; Petković, Jelena; Paar, Nils; Martínez-Pinedo, Gabriel

    2016-06-01

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei. Aside from the astrophysical applications, the results of this calculation can also be employed in the modeling of the electron and antineutrino spectra from nuclear reactors.

  1. Beta decay rates of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Marketin, Tomislav; Petković, Jelena; Paar, Nils; Huther, Lutz; Martínez-Pinedo, Gabriel

    2016-01-01

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei. Aside from the astrophysical applications, the results of this calculation can also be employed in the modeling of the electron and antineutrino spectra from nuclear reactors.

  2. Beta decay rates of neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Marketin, Tomislav, E-mail: marketin@phy.hr; Petković, Jelena; Paar, Nils [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Huther, Lutz [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); Martínez-Pinedo, Gabriel [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); GSI Helmholtzzentrum für Schwerioneneforschung, Planckstraße 1, 64291 Darmstadt (Germany)

    2016-06-21

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei. Aside from the astrophysical applications, the results of this calculation can also be employed in the modeling of the electron and antineutrino spectra from nuclear reactors.

  3. Beta decay rates of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Marketin, Tomislav; Huther, Lutz; Martínez-Pinedo, Gabriel

    2015-01-01

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. Currently, a single large-scale calculation is available based on a QRPA calculation with a schematic interaction on top of the Finite Range Droplet Model. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei

  4. Beta decay rates of neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Marketin, Tomislav, E-mail: marketin@phy.hr [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Huther, Lutz [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); Martínez-Pinedo, Gabriel [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); GSI Helmholtzzentrum für Schwerioneneforschung, Planckstraße 1, 64291 Darmstadt (Germany)

    2015-10-15

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. Currently, a single large-scale calculation is available based on a QRPA calculation with a schematic interaction on top of the Finite Range Droplet Model. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei.

  5. Evaluation of spent fuel isotopics, radiation spectra and decay heat using the scale computational system

    International Nuclear Information System (INIS)

    Parks, C.V.; Hermann, O.W.; Ryman, J.C.

    1986-01-01

    In order to be a self-sufficient system for transport/storage cask shielding and heat transfer analysis, the SCALE system developers included modules to evaluate spent fuel radiation spectra and decay heat. The primary module developed for these analyses is ORIGEN-S which is an updated verision of the original ORIGEN code. The COUPLE module was also developed to enable ORIGEN-S to easily utilize multigroup cross sections and neutron flux data during a depletion analysis. Finally, the SAS2 control module was developed for automating the depletion and decay via ORIGEN-S while using burnup-dependent neutronic data based on a user-specified fuel assembly and reactor history. The ORIGEN-S data libraries available for depletion and decay have also been significantly updated from that developed with the original ORIGEN code

  6. Neutron Interactions in the CUORE Neutrinoless Double Beta Decay Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dolinski, Michelle Jean [Univ. of California, Berkeley, CA (United States)

    2008-10-01

    Neutrinoless double beta decay (0vDBD) is a lepton-number violating process that can occur only for a massive Majorana neutrino. The search for 0vDBD is currently the only practical experimental way to determine whether neutrinos are identical to their own antiparticles (Majorana neutrinos) or have distinct particle and anti-particle states (Dirac neutrinos). In addition, the observation of 0vDBD can provide information about the absolute mass scale of the neutrino. The Cuoricino experiment was a sensitive search for 0vDBD, as well as a proof of principle for the next generation experiment, CUORE. CUORE will search for 0vDBD of 130Te with a ton-scale array of unenriched TeO2 bolometers. By increasing mass and decreasing the background for 0vDBD, the half-life sensitivity of CUORE will be a factor of twenty better than that of Cuoricino. The site for both of these experiments is the Laboratori Nazionali del Gran Sasso, an underground laboratory with 3300 meters water equivalent rock overburden and a cosmic ray muon attenuation factor of 10-6. Because of the extreme low background requirements for CUORE, it is important that all potential sources of background in the 0vDBD peak region at 2530 keV are well understood. One potential source of background for CUORE comes from neutrons, which can be produced underground both by (α,n) reactions and by fast cosmic ray muon interactions. Preliminary simulations by the CUORE collaboration indicate that these backgrounds will be negligible for CUORE. However, in order to accurately simulate the expected neutron background, it is important to understand the cross sections for neutron interactions with detector materials. In order to help refine these simulations, I have measured the gamma-ray production cross sections for interactions of neutrons on the abundant stable isotopes of Te using the GEANIE detector array at the Los Alamos Neutron Science Center. In addition, I have used the GEANIE

  7. Search for time reversal violation in neutron decay

    International Nuclear Information System (INIS)

    Gorel, P.

    2006-06-01

    The topic of this thesis is the implementation of an experimental setup designed to measure the R- and N-parameters in polarized neutron decay, together with the data analysis. Four observables are necessary for this measurement: the neutron polarization, the electron momentum and both transverse components of the electron polarization. These last two are measured using a Mott polarimeter. The other observables are determined using the same detectors. The precision to be reached on the R-parameter is 0.5%. A non zero value would sign a time reversal invariance violation and therefore would be a hint of physics beyond the Standard Model. This document presents the work done to prepare and optimize the experimental setup before the data acquisition run performed in 2004. Particular care was taken on the scintillator walls, used to trigger the acquisition and measure the electron energy. The second part concerns the implementation of methods to extract R and N from the data, and the study of the background recorded simultaneously. (author)

  8. Neutron Spectrometry for Radiation Protection Purposes

    International Nuclear Information System (INIS)

    McDonald, Joseph C.

    2001-01-01

    Determination of the dose equivalent is required for radiation protection purposes, however such a determination is quite difficult for neutron radiation. In order to perform accurate dosimetric determinations, it is necessary to acquire information about the neutron fluence spectrum in the workplace as well as the reference radiations used to calibrate dosimetric instruments. This information can then be used to select the appropriate dosimetric instrument, the optimum calibration condition or to establish correction factors that account for the differences in calibration and workplace conditions. For quite some time, neutron spectrometry has been used for these purposes. A brief review of the applications of spectrometers in radiation protection and some recommendations for further development are given here

  9. Neutron spectrometry for radiation protection purposes

    CERN Document Server

    McDonald, J C; Alberts, W G

    2002-01-01

    Determination of the dose equivalent is required for radiation protection purposes, however such a determination is quite difficult for neutron radiation. In order to perform accurate dosimetric determinations, it is advantageous to acquire information about the neutron fluence spectrum in the workplace as well as the reference radiations used to calibrate dosimetric instruments. This information can then be used to select the appropriate dosimetric instrument, the optimum calibration condition or to establish correction factors that account for the differences in calibration and workplace conditions. For quite some time, neutron spectrometry has been used for these purposes. A brief review of the applications of spectrometers in radiation protection and some recommendations for further development are given here.

  10. Aspects of radiative K{sup +}{sub e3} decays

    Energy Technology Data Exchange (ETDEWEB)

    Kubis, B. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Mueller, E.H. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); University of Edinburgh, School of Physics, Edinburgh (United Kingdom); Gasser, J.; Schmid, M. [Universitaet Bern, Institut fuer theoretische Physik, Bern (Switzerland)

    2007-04-15

    We re-investigate the radiative charged kaon decay K{sup {+-}}{yields}{pi}{sup 0}e{sup {+-}}{nu}{sub e}{gamma} [K{sub e3{gamma}}{sup {+-}}] in chiral perturbation theory, merging the chiral expansion with Low's theorem. We thoroughly analyze the precision of the predicted branching ratio relative to the non-radiative decay channel. Structure dependent terms and their impact on differential decay distributions are investigated in detail, and the possibility to see effects of the chiral anomaly in this decay channel is emphasized. (orig.)

  11. Aspects of radiative K+e3 decays

    International Nuclear Information System (INIS)

    Kubis, B.; Mueller, E.H.; Gasser, J.; Schmid, M.

    2007-01-01

    We re-investigate the radiative charged kaon decay K ± →π 0 e ± ν e γ [K e3γ ± ] in chiral perturbation theory, merging the chiral expansion with Low's theorem. We thoroughly analyze the precision of the predicted branching ratio relative to the non-radiative decay channel. Structure dependent terms and their impact on differential decay distributions are investigated in detail, and the possibility to see effects of the chiral anomaly in this decay channel is emphasized. (orig.)

  12. Radiative decays of vector mesons in the chiral bag model

    International Nuclear Information System (INIS)

    Tabachenko, A.N.

    1988-01-01

    A new model of radiative π-meson decays of vector mesons in the chiral bag model is proposed. The quark-π-meson interaction has the form of a pseudoscalar coupling and is located on the bag surface. The vector meson decay width depends on the quark masses, the π-meson decay constant, the radius of the bag, and the free parameter Z 2 , which specifies the disappearance of the bag during the decay. The obtained results for the omega- and p-decay widths are in satisfactory agreement with the experiment

  13. Scalar mesons in φ radiative decay

    International Nuclear Information System (INIS)

    Close, F.E.; Isgur, N.; Kumano, S.

    1992-06-01

    Existing predictions for the branching ratio for φ → KK γ via φ → S γ (where S denotes one of the scalar mesons f o (975) and a o (980)) vary by several orders of magnitude. Given the importance of these processes for both hadron spectroscopy and charge-parity-violation studies at φ factories (where φ→ K o K-bar o γ poses a possible background problem), this state of affairs is very undesirable. We show that the variety of predictions is due in part to errors and in part to differences in modelling. The latter variation leads us to argue that the radiative decays of these scalar states are interesting in their own right and may offer unique insights into the nature of the scalar mesons. As a byproduct we find that the branching ratio for φ → K o K-bar o γ is approx. -7 ) and will pose no significant background to proposed studies of CP-violation. (Author)

  14. Radiation shielding for neutron guides

    International Nuclear Information System (INIS)

    Ersez, T.; Braoudakis, G.; Osborn, J.C.

    2005-01-01

    Full text: Models of the neutron guide shielding for the out of bunker guides on the thermal and cold neutron beam lines of the OPAL Reactor (ANSTO) were constructed using the Monte Carlo code MCNP 4B. The neutrons that were not reflected inside the guides but were absorbed by the supermirror (SM) layers were noted to be a significant source of gammas. Gammas also arise from neutrons absorbed by the B, Si, Na and K contained in the glass. The proposed shielding design has produced compact shielding assemblies. These arrangements are consistent with safety requirements, floor load limits, and cost constraints. To verify the design a prototype was assembled consisting of 120mm thick Pb(96%)Sb(4%) walls resting on a concrete block. There was good agreement between experimental measurements and calculated dose rates for bulk shield regions. (authors)

  15. Radiation shielding for neutron guides

    International Nuclear Information System (INIS)

    Ersez, T.; Braoudakis, G.; Osborn, J.C.

    2006-01-01

    Models of the neutron guide shielding for the out of bunker guides on the thermal and cold neutron beam lines of the OPAL Reactor (ANSTO) were constructed using the Monte Carlo code MCNP 4B. The neutrons that were not reflected inside the guides but were absorbed by the supermirror (SM) layers were noted to be a significant source of gammas. Gammas also arise from neutrons absorbed by the B, Si, Na and K contained in the glass. The proposed shielding design has produced compact shielding assemblies. These arrangements are consistent with safety requirements, floor load limits, and cost constraints. To verify the design a prototype was assembled consisting of 120 mm thick Pb(96%)Sb(4%) walls resting on a concrete block. There was good agreement between experimental measurements and calculated dose rates for bulk shield regions

  16. T violation in radiative β decay and electric dipole moments

    Directory of Open Access Journals (Sweden)

    W. Dekens

    2015-12-01

    Full Text Available In radiative β decay, T violation can be studied through a spin-independent T-odd correlation. We consider contributions to this correlation by beyond the standard model (BSM sources of T-violation, arising above the electroweak scale. At the same time such sources, parametrized by dimension-6 operators, can induce electric dipole moments (EDMs. As a consequence, the manifestations of the T-odd BSM physics in radiative β decay and EDMs are not independent. Here we exploit this connection to show that current EDM bounds already strongly constrain the spin-independent T-odd correlation in radiative β decay.

  17. T violation in radiative β decay and electric dipole moments

    Energy Technology Data Exchange (ETDEWEB)

    Dekens, W.; Vos, K.K., E-mail: k.k.vos@rug.nl

    2015-12-17

    In radiative β decay, T violation can be studied through a spin-independent T-odd correlation. We consider contributions to this correlation by beyond the standard model (BSM) sources of T-violation, arising above the electroweak scale. At the same time such sources, parametrized by dimension-6 operators, can induce electric dipole moments (EDMs). As a consequence, the manifestations of the T-odd BSM physics in radiative β decay and EDMs are not independent. Here we exploit this connection to show that current EDM bounds already strongly constrain the spin-independent T-odd correlation in radiative β decay.

  18. Extracting and Using Photon Polarization Information in Radiative B Decays

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, Yuval

    2000-05-09

    The authors discuss the uses of conversion electron pairs for extracting photon polarization information in weak radiative B decays. Both cases of leptons produced through a virtual and real photon are considered. Measurements of the angular correlation between the (K-pi) and (e{sup +}e{sup {minus}}) decay planes in B --> K*(--> K-pi)gamma (*)(--> e{sup +}e{sup {minus}}) decays can be used to determine the helicity amplitudes in the radiative B --> K*gamma decays. A large right-handed helicity amplitude in B-bar decays is a signal of new physics. The time-dependent CP asymmetry in the B{sup 0} decay angular correlation is shown to measure sin 2-beta and cos 2-beta with little hadronic uncertainty.

  19. Neutron radiation damage studies on silicon detectors

    International Nuclear Information System (INIS)

    Li, Zheng; Chen, W.; Kraner, H.W.

    1990-10-01

    Effects of neutron radiation on electrical properties of Si detectors have been studied. At high neutron fluence (Φ n ≥ 10 12 n/cm 2 ), C-V characteristics of detectors with high resistivities (ρ ≥ 1 kΩ-cm) become frequency dependent. A two-trap level model describing this frequency dependent effect is proposed. Room temperature anneal of neutron damaged (at LN 2 temperature) detectors shows three anneal stages, while only two anneal stages were observed in elevated temperature anneal. 19 refs., 14 figs

  20. The spectrometer PERKEO III and the decay of free neutrons; Das Spektrometer PERKEO III und der Zerfall des freien Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Maerkisch, B.M.

    2006-10-18

    The Standard Model of particle physics describes neutron decay with three parameters. In contrast to that, a multitude of observables are accessible experimentally. With precision measurements sensitive tests of the Standard Model are thus possible. The neutron decay spectrometer PERKEO III was designed and built as part of this work. It will replace its predecessor PERKEO II, which has reached its systematical and statistical limits. With the new instrument measurements with continuous and pulsed neutron beams become feasible. This either provides an increase in statistics of up to two orders of magnitude, or eliminates the two major instrument specific sources of systematical corrections. In our first measurement in winter 2006/2007, the available event rate will be used to determine weak magnetism from the electron asymmetry A. Previously, this value was not statistically accessible in neutron decay. Systematics are analyzed with the help of our measurement with PERKEO II. For this measurement PERKEO III will be installed at the neutron guide H113 at the Institute Laue-Langevin, Grenoble. The neutron beam from this guide is characterized and a model is given, which allows the rapid calculation of beam profiles and absolute event rates from such a beam. In preparation of a future neutron decay instrument the reflective properties of two non-magnetic neutron mirrors were measured. (orig.)

  1. Radiation therapy with fast neutrons: A review

    International Nuclear Information System (INIS)

    Jones, D.T.L.; Wambersie, A.

    2007-01-01

    Because of their biological effects fast neutrons are most effective in treating large, slow-growing tumours which are resistant to conventional X-radiation. Patients are treated typically 3-4 times per week for 4-5 weeks (sometimes in combination with X-radiation) for a variety of conditions such as carcinomas of the head and neck, salivary gland, paranasal sinus and breast; soft tissue, bone and uterine sarcomas and malignant melanomas. It is estimated that about 27,000 patients have undergone fast neutron therapy to date

  2. Studying radiative B decays with the Atlas detector

    International Nuclear Information System (INIS)

    Viret, S.

    2004-09-01

    This thesis is dedicated to the study of radiative B decays with the ATLAS detector at the LHC (large hadron collider). Radiative decays belong to the rare decays family. Rare decays transitions involve flavor changing neutral currents (for example b → sγ), which are forbidden at the lowest order in the Standard Model. Therefore these processes occur only at the next order, thus involving penguin or box diagrams, which are very sensitive to 'new physics' contributions. The main goal of our study is to show that it would be possible to develop an online selection strategy for radiative B decays with the ATLAS detector. To this end, we have studied the treatment of low energy photons by the ATLAS electromagnetic calorimeter (ECal). Our analysis shows that ATLAS ECal will be efficient with these particles. This property is extensively used in the next section, where a selection strategy for radiative B decays is proposed. Indeed, we look for a low energy region of interest in the ECal as soon as the level 1 of the trigger. Then, photon identification cuts are performed in this region at level 2. However, a large part of the proposed selection scheme is also based on the inner detector, particularly at level 2. The final results show that large amounts of signal events could be collected in only one year by ATLAS. A preliminary significance (S/√B) estimation is also presented. Encouraging results concerning the observability of exclusive radiative B decays are obtained. (author)

  3. Neutron dosimetry for radiation damage in fission and fusion reactors

    International Nuclear Information System (INIS)

    Smith, D.L.

    1979-01-01

    The properties of materials subjected to the intense neutron radiation fields characteristic of fission power reactors or proposed fusion energy devices is a field of extensive current research. These investigations seek important information relevant to the safety and economics of nuclear energy. In high-level radiation environments, neutron metrology is accomplished predominantly with passive techniques which require detailed knowledge about many nuclear reactions. The quality of neutron dosimetry has increased noticeably during the past decade owing to the availability of new data and evaluations for both integral and differential cross sections, better quantitative understanding of radioactive decay processes, improvements in radiation detection technology, and the development of reliable spectrum unfolding procedures. However, there are problems caused by the persistence of serious integral-differential discrepancies for several important reactions. There is a need to further develop the data base for exothermic and low-threshold reactions needed in thermal and fast-fission dosimetry, and for high-threshold reactions needed in fusion-energy dosimetry. The unsatisfied data requirements for fission reactor dosimetry appear to be relatively modest and well defined, while the needs for fusion are extensive and less well defined because of the immature state of fusion technology. These various data requirements are examined with the goal of providing suggestions for continued dosimetry-related nuclear data research

  4. Simultaneous thermal neutron decay time and porosity logging system

    International Nuclear Information System (INIS)

    Smith, H.D. Jr.; Smith, M.P.; Schultz, W.E.

    1979-01-01

    A simultaneous pulsed neutron porosity and thermal neutron capture cross section logging system is provided for radiological well logging of subsurface earth formations. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector, and a combination gamma ray and fast neutron detector is moved through a borehole. Repetitive bursts of neutrons irradiate the earth formations; and, during the bursts, the fast neutron and epithermal neutron populations are sampled. During the interval between bursts the thermal neutron capture gamma ray population is sampled in two or more time intervals. The fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity phi. The capture gamma ray measurements are combined to provide a simultaneous determination of the thermal neutron capture cross section Σ

  5. Radiative decays of the Upsilon(1S) meson

    International Nuclear Information System (INIS)

    Besson, D.Z.

    1986-01-01

    Using the CLEO detector at the Cornell Electron Storage Ring, the author is able to measure the QCD scaling parameter Λ/sub MS/ as well as the strong coupling constant α/sub s/ through a measurement of the direct photon energy spectrum resulting from decays of the Upsilon(1S) meson. The author finds fair agreement with previous work. In addition, the author sets limits on exclusive two-body radiative decays of the Upsilon(1S) meson and see no evidence for the type of such two-body decays which are observed in psi decays

  6. Apparatus and method for the simultaneous detection of neutrons and ionizing electromagnetic radiation

    Science.gov (United States)

    Bell, Zane W.

    2000-01-01

    A sensor for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising: a sensor for the detection of gamma radiation, the sensor defining a sensing head; the sensor further defining an output end in communication with the sensing head; and an exterior neutron-sensitive material configured to form around the sensing head; wherein the neutron-sensitive material, subsequent to the capture of the neutron, fissions into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the first excited state decaying via the emission of a single gamma ray at 478 keV which can in turn be detected by the sensing head; and wherein the sensing head can also detect the ionizing electromagnetic radiation from an incident radiation field without significant interference from the neutron-sensitive material. A method for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising the steps of: providing a gamma ray sensitive detector comprising a sensing head and an output end; conforming an exterior neutron-sensitive material configured to form around the sensing head of the detector; capturing neutrons by the sensing head causing the neutron-sensitive material to fission into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the state decaying via the emission of a single gamma ray at 478 keV; sensing gamma rays entering the detector through the neutron-sensitive material; and producing an output through a readout device coupled to the output end; wherein the detector provides an output which is proportional to the energy of the absorbed ionizing electromagnetic radiation.

  7. Filtered thermal neutron captured cross sections measurements and decay heat calculations

    International Nuclear Information System (INIS)

    Pham Ngoc Son; Vuong Huu Tan

    2015-01-01

    Recently, a pure thermal neutron beam has been developed for neutron capture measurements based on the horizontal channel No.2 of the research reactor at the Nuclear Research Institute, Dalat. The original reactor neutron spectrum is transmitted through an optimal composition of Bi and Si single crystals for delivering a thermal neutron beam with Cadmium ratio (R ed ) of 420 and neutron flux (Φ th ) of 1.6*10 6 n/cm 2 .s. This thermal neutron beam has been applied for measurements of capture cross sections for nuclide of 51 V, by the activation method relative to the standard reaction 197 Au(n,γ) 198 Au. In addition to the activities of neutron capture cross sections measurements, the study on nuclear decay heat calculations has been also considered to be developed at the Institute. Some results on calculation procedure and decay heat values calculated with update nuclear database for 235 U are introduced in this report. (author)

  8. An electroweak enigma: Hyperon radiative decays

    Energy Technology Data Exchange (ETDEWEB)

    Vorobyov, A., (spokesperson); /St. Petersburg, INP; Jastrzembski, E.; Lach, J.; Marriner, J.; /Fermilab; Golovtsov, V.; Krivshich, A.; Schegelsky, V.; Smirnov, N.; Terentiev, N.K.; Uvarov, L.; /St. Petersburg, INP; McCliment, E.; Newsom, C.; Norbeck, E.; /Iowa U.; Cooper, P.S.; /Yale U.

    1985-04-03

    The main thrust of this experiment will be to measure the asymmetry parameter for the electroweak decay {Sigma}{sup +} {yields} p{gamma} and verify its branching ratio. As a secondary goal they will measure, or set new upper limits for, the branching ratio of the electroweak decay {Xi}{sup -} {yields} {Sigma}{sup -}{gamma}. Since the {Xi}{sup -} are expected to be polarized, information on the asymmetry parameter may also be available.

  9. Methodology of measurement of thermal neutron time decay constant in Canberra 35+ MCA system

    Energy Technology Data Exchange (ETDEWEB)

    Drozdowicz, K.; Gabanska, B.; Igielski, A.; Krynicka, E.; Woznicka, U. [Institute of Nuclear Physics, Cracow (Poland)

    1993-12-31

    A method of the thermal neutron time decay constant measurement in small bounded media is presented. A 14 MeV pulsed neutron generator is the neutron source. The system of recording of a die-away curve of thermal neutrons consists of a {sup 3}He detector and of a multichannel time analyzer based on analyzer Canberra 35+ with multi scaler module MCS 7880 (microsecond range). Optimum parameters for the measuring system are considered. Experimental verification of a dead time of the instrumentation system is made and a count-loss correction is incorporated into the data treatment. An attention is paid to evaluate with a high accuracy the fundamental mode decay constant of the registered decaying curve. A new procedure of the determination of the decay constant by a multiple recording of the die-away curve is presented and results of test measurements are shown. (author). 11 refs, 12 figs, 4 tabs.

  10. Methodology of measurement of thermal neutron time decay constant in Canberra 35+ MCA system

    International Nuclear Information System (INIS)

    Drozdowicz, K.; Gabanska, B.; Igielski, A.; Krynicka, E.; Woznicka, U.

    1993-01-01

    A method of the thermal neutron time decay constant measurement in small bounded media is presented. A 14 MeV pulsed neutron generator is the neutron source. The system of recording of a die-away curve of thermal neutrons consists of a 3 He detector and of a multichannel time analyzer based on analyzer Canberra 35+ with multi scaler module MCS 7880 (microsecond range). Optimum parameters for the measuring system are considered. Experimental verification of a dead time of the instrumentation system is made and a count-loss correction is incorporated into the data treatment. An attention is paid to evaluate with a high accuracy the fundamental mode decay constant of the registered decaying curve. A new procedure of the determination of the decay constant by a multiple recording of the die-away curve is presented and results of test measurements are shown. (author). 11 refs, 12 figs, 4 tabs

  11. Methodology of measurement of thermal neutron time decay constant in Canberra 35+ MCA system

    Energy Technology Data Exchange (ETDEWEB)

    Drozdowicz, K; Gabanska, B; Igielski, A; Krynicka, E; Woznicka, U [Institute of Nuclear Physics, Cracow (Poland)

    1994-12-31

    A method of the thermal neutron time decay constant measurement in small bounded media is presented. A 14 MeV pulsed neutron generator is the neutron source. The system of recording of a die-away curve of thermal neutrons consists of a {sup 3}He detector and of a multichannel time analyzer based on analyzer Canberra 35+ with multi scaler module MCS 7880 (microsecond range). Optimum parameters for the measuring system are considered. Experimental verification of a dead time of the instrumentation system is made and a count-loss correction is incorporated into the data treatment. An attention is paid to evaluate with a high accuracy the fundamental mode decay constant of the registered decaying curve. A new procedure of the determination of the decay constant by a multiple recording of the die-away curve is presented and results of test measurements are shown. (author). 11 refs, 12 figs, 4 tabs.

  12. Detection system for neutron β decay correlations in the UCNB and Nab experiments

    Energy Technology Data Exchange (ETDEWEB)

    Broussard, L.J., E-mail: broussardlj@ornl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zeck, B.A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); North Carolina State University, Raleigh, NC 27695 (United States); Adamek, E.R. [Indiana University, Bloomington, IN 47405 (United States); Baeßler, S. [University of Virginia, Charlottesville, VA 22904 (United States); Birge, N. [University of Tennessee, Knoxville, TN 37996 (United States); Blatnik, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Cleveland State University, Cleveland, OH 44115 (United States); Bowman, J.D. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Brandt, A.E. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); North Carolina State University, Raleigh, NC 27695 (United States); Brown, M. [University of Kentucky, Lexington, KY 40506 (United States); Burkhart, J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Callahan, N.B. [Indiana University, Bloomington, IN 47405 (United States); Clayton, S.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Crawford, C. [University of Kentucky, Lexington, KY 40506 (United States); Cude-Woods, C. [North Carolina State University, Raleigh, NC 27695 (United States); Currie, S. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Dees, E.B. [North Carolina State University, Raleigh, NC 27695 (United States); Ding, X. [Virginia Polytechnic Institute & State University, Blacksburg, VA 24061 (United States); Fomin, N. [University of Tennessee, Knoxville, TN 37996 (United States); Frlez, E.; Fry, J. [University of Virginia, Charlottesville, VA 22904 (United States); and others

    2017-03-21

    We describe a detection system designed for precise measurements of angular correlations in neutron β decay. The system is based on thick, large area, highly segmented silicon detectors developed in collaboration with Micron Semiconductor, Ltd. The prototype system meets specifications for β electron detection with energy thresholds below 10 keV, energy resolution of ∼3 keV FWHM, and rise time of ∼50 ns with 19 of the 127 detector pixels instrumented. Using ultracold neutrons at the Los Alamos Neutron Science Center, we have demonstrated the coincident detection of β particles and recoil protons from neutron β decay. The fully instrumented detection system will be implemented in the UCNB and Nab experiments to determine the neutron β decay parameters B, a, and b.

  13. Measuring element for the detection and determination of radiation doses of gamma radiation and neutrons

    International Nuclear Information System (INIS)

    Jahn, W.; Piesch, E.

    1975-01-01

    A measuring element detects and proves both gamma and neutron radiation. The element includes a photoluminescent material which stores gamma radiation and particles of arsenic and phosphorus embedded in the photoluminescent material for detecting neutron radiation. (U.S.)

  14. Neutron measuring instruments for radiation protection

    International Nuclear Information System (INIS)

    Heinzelmann, M.; Schneider, W.; Hoefert, M.; Kuehn, H.; Jahr, R.; Wagner, S.; Piesch, E.

    1979-09-01

    The present report deals with selected topics from the field of neutron dosimetry for radiation protection connected with the work of the subcommittee 6802 in the Standards Committee on Radiology (NAR) of the German Standards Institute (DIN). It is a sort of material collection. The topics are: 1. Measurement of the absorbed-energy dose by a) ionization chambers in fields of mixed radiation and b) recoil-proton proportional counting tubes. 2. Measurement of the equivalent dose, neutron monitors, combination methods by a) rem-meters, b) recoil-proton counting tubes, c) recombination method, tissue-equivalent proportional counters, activation methods for high energies in fields of mixed radiation, d) personnel dosimetry by means of ionization chambers and counting tubes, e) dosimetry by means of activation methods, nuclear track films, nonphotographic nuclear track detectors and solid-state dosimeters. (orig./HP) [de

  15. Code ACTIVE for calculation of the transmutation, induced activity and decay heat in neutron irradiation

    International Nuclear Information System (INIS)

    Ioki, Kimihiro; Harada, Yuhei; Asami, Naoto.

    1976-03-01

    The computer code ACTIVE has been prepared for calculation of the transmutation rate, induced activity and decay heat. Calculations are carried out with activation chain and spatial distribution of neutron energy spectrum. The spatial distribution of secondary gamma-ray source due to the unstable nuclides is also obtainable. Special attension is paid to the short life decays. (auth.)

  16. Measurements of neutron radiation in aircraft

    International Nuclear Information System (INIS)

    Vukovic, B.; Poje, M.; Varga, M.; Radolic, V.; Miklavcic, I.; Faj, D.; Stanic, D.; Planinic, J.

    2010-01-01

    Radiation environment is a complex mixture of charged particles of the solar and galactic origin, as well as of secondary particles created in an interaction of galactic cosmic particles with the nuclei of the Earth's atmosphere. A radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. In order to measure a neutron component of the cosmic radiation, we investigated a few combinations of a track etch detector (CR-39, LR-115) with a plastic converter or boron foil. Detector calibration was performed on neutrons coming from the nuclear reactor, as well as in the CERN-EU high-energy Reference Field (CERF) facility. From November 2007 to September 2008, the neutron dose equivalent was measured by the track detectors during five aircraft flights, in the north geographical latitude from 21 o to 58 o ; the respective average dose rate, determined by using the D-4 detector (CR-39/B), was H n =5.9 μSv/h. The photon dose rate, measured by the electronic dosimeter RAD-60 SE, had the average value of H f =1.4 μSv/h.

  17. Measurements of neutron radiation in aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, B.; Poje, M.; Varga, M.; Radolic, V.; Miklavcic, I. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia); Faj, D. [Clinical Hospital Osijek (Croatia); Stanic, D. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia); Planinic, J., E-mail: planinic@ffos.h [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia)

    2010-12-15

    Radiation environment is a complex mixture of charged particles of the solar and galactic origin, as well as of secondary particles created in an interaction of galactic cosmic particles with the nuclei of the Earth's atmosphere. A radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. In order to measure a neutron component of the cosmic radiation, we investigated a few combinations of a track etch detector (CR-39, LR-115) with a plastic converter or boron foil. Detector calibration was performed on neutrons coming from the nuclear reactor, as well as in the CERN-EU high-energy Reference Field (CERF) facility. From November 2007 to September 2008, the neutron dose equivalent was measured by the track detectors during five aircraft flights, in the north geographical latitude from 21{sup o} to 58{sup o}; the respective average dose rate, determined by using the D-4 detector (CR-39/B), was H{sub n}=5.9 {mu}Sv/h. The photon dose rate, measured by the electronic dosimeter RAD-60 SE, had the average value of H{sub f}=1.4 {mu}Sv/h.

  18. Anomalies in radiation decays of charmed mesons

    International Nuclear Information System (INIS)

    Kalinovskij, Yu.L.; Pervushin, V.N.; Sarikov, N.A.

    1986-01-01

    The amplitudes of the charmed meson decays D→0 - +0 - +γ and F→0 - +0 - +γ are calculated in the framework of the SU(4)xSU(4)-chiral Lagrangians with account for anomalies. It is shown that in this approach no E1-transition exists

  19. Dispersion and decay of collective modes in neutron star cores

    OpenAIRE

    Kobyakov, D. N.; Pethick, C. J.; Reddy, S.; Schwenk, A.

    2017-01-01

    We calculate the frequencies of collective modes of neutrons, protons and electrons in the outer core of neutron stars. The neutrons and protons are treated in a hydrodynamic approximation and the electrons are regarded as collisionless. The coupling of the nucleons to the electrons leads to Landau damping of the collective modes and to significant dispersion of the low-lying modes. We investigate the sensitivity of the mode frequencies to the strength of entrainment between neutrons and prot...

  20. Time reversal in polarized neutron decay: the emiT experiment

    CERN Document Server

    Jones, G L; Anaya, J M; Bowles, T J; Chupp, T E; Coulter, K P; Dewey, M S; Freedman, S J; Fujikawa, B K; García, A; Greene, G L; Hwang, S R; Lising, L J; Mumm, H P; Nico, J S; Robertson, R G H; Steiger, T D; Teasdale, W A; Thompson, A K; Wasserman, E G; Wietfeldt, F E; Wilkerson, J F

    2000-01-01

    The standard electro-weak model predicts negligible violation of time-reversal invariance in light quark processes. We report on an experimental test of time-reversal invariance in the beta decay of polarized neutrons as a search for physics beyond the standard model. The emiT collaboration has measured the time-reversal-violating triple-correlation in neutron beta decay between the neutron spin, electron momentum, and neutrino momentum often referred to as the D coefficient. The first run of the experiment produced 14 million events which are currently being analyzed. However, a second run with improved detectors should provide greater statistical precision and reduced systematic uncertainties.

  1. Simultaneous thermal neutron decay time and porosity logging system

    International Nuclear Information System (INIS)

    Schultz, W.E.; Smith, H.D.; Smith, M.P.

    1980-01-01

    An improved method and apparatus are described for simultaneously measuring the porosity and thermal neutron capture cross section of earth formations in situ in the vicinity of a well borehole using pulsed neutron well logging techniques. The logging tool which is moved through the borehole consists of a 14 MeV pulsed neutron source, an epithermal neutron detector and a combination gamma ray and fast neutron detector. The associated gating systems, counters and combined digital computer are sited above ground. (U.K.)

  2. Radiative corrections in K→πl+l- decays

    International Nuclear Information System (INIS)

    Kubis, Bastian; Schmidt, Rebekka

    2010-01-01

    We calculate radiative corrections to the flavor-changing neutral current process K→πl + l - , both for charged and neutral kaon decays. While the soft-photon approximation is shown to work well for the muon channels, we discuss the necessity of further phase space cuts with electrons in the final state. It is also shown how to transfer our results to other decays such as η→γl + l - or ω→π 0 l + l - . (orig.)

  3. Radiative decays of resonances on the lattice

    International Nuclear Information System (INIS)

    Agadjanov, Andria; Bernard, Véronique; Meißner, Ulf-G.; Rusetsky, Akaki

    2016-01-01

    We discuss a generalization of the Lüscher approach to the calculation of the matrix elements of the unstable states. A theoretical framework for the lattice extraction of the ΔNγ* transition form factors is formulated. The procedure to measure the form factors at the resonance pole is given. The current theoretical progress on the B → K*γ* decays is briefly summarized

  4. Studies of phi meson radiative decays with KLOE

    International Nuclear Information System (INIS)

    Aloisio, A.; Ambrosino, F.; Antonelli, A.; Antonelli, M.; Bacci, C.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocci, V.; Bossi, F.; Branchini, P.; Bulychjov, S.A.; Caloi, R.; Campana, P.; Capon, G.; Carboni, G.; Casarsa, M.; Casavola, V.; Cataldi, G.; Ceradini, F.; Cervelli, F.; Cevenini, F.; Chiefari, G.; Ciambrone, P.; Conetti, S.; De Lucia, E.; De Robertis, G.; De Simone, P.; De Zorzi, G.; Dell'Agnello, S.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Falco, S.; Doria, A.; Dreucci, M.; Erriquez, O.; Farilla, A.; Felici, G.; Ferrari, A.; Ferrer, M.L.; Finocchiaro, G.; Forti, C.; Franceschi, A.; Franzini, P.; Gatt, C.; Gauzzi, P.; Giovannella, S.; Gorini, E.; Grancagnolo, F.; Graziani, E.; Han, S.W.; Incagli, M.; Ingrosso, L.; Kluge, W.; Kuo, C.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Leone, D.; Lu, F.; Martemianov, M.; Matsyuk, M.; Mei, W.; Merola, L.; Messi, R.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nedosekin, A.; Nguyen, F.; Palutan, M.; Pasqualucci, E.; Passalacqua, L.; Passeri, A.; Patera, V.; Petrolo, E.; Pontecorvo, L.; Primavera, M.; Ruggieri, F.; Santangelo, P.; Santovetti, E.; Saracino, G.; Schamberger, R.D.; Sciascia, B.; Sciubba, A.; Scuri, F.; Sfiligoi, I.; Spadaro, T.; Spiriti, E.; Tong, G.L.; Tortora, L.; Valente, E.; Valente, P.; Valeriani, B.; Vernanzoni, G.; Veneziano, S.; Ventura, A.; Xu, G.; Yu, G.W.

    2003-01-01

    A sample of 5.3 x 10 7 phi mesons, produced at the Frascati phi-factory DAPHINE, has been used by the KLOE Collaboration to study the phi radiative decays. The decays phi → ηπ 0 γ and phi → π o π o γ have been exploited to study the scalar mesons a o (980) and f o (980). Furthermore a new determination of the η - η' mixing angle has been obtained from the measurement of the ratio of the decay rates of phi → η'γ to phi → ηγ to phi → ηγ

  5. Constraints on new physics from radiative B decays

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Ayan [INFN, Sezione di Roma,I-00185 Rome (Italy); Straub, David M. [Excellence Cluster Universe, TUM,Boltzmannstr. 2, 85748 Garching (Germany)

    2017-04-05

    A new phase for the measurements of radiative decay modes in b→s transitions has started with new measurements of exclusive modes by LHCb and with Belle-II showing distinctive promises in both inclusive and exclusive channels. After critically reviewing the hadronic uncertainties in exclusive radiative decays, we analyze the impact of recent measurements of the branching ratio and mass-eigenstate rate asymmetry in B{sub s}→ϕγ and of the angular distribution of B→K{sup ∗}e{sup +}e{sup −} at low q{sup 2} on new physics in the b→sγ transition.

  6. Dispersion and decay of collective modes in neutron star cores

    Science.gov (United States)

    Kobyakov, D. N.; Pethick, C. J.; Reddy, S.; Schwenk, A.

    2017-08-01

    We calculate the frequencies of collective modes of neutrons, protons, and electrons in the outer core of neutron stars. The neutrons and protons are treated in a hydrodynamic approximation and the electrons are regarded as collisionless. The coupling of the nucleons to the electrons leads to Landau damping of the collective modes and to significant dispersion of the low-lying modes. We investigate the sensitivity of the mode frequencies to the strength of entrainment between neutrons and protons, which is not well characterized. The contribution of collective modes to the thermal conductivity is evaluated.

  7. Neutron correlations in the decay of the first excited state of {sup 11}Li

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.K., E-mail: jsmith@triumf.ca [National Superconducting Cyclotron Laboratory, East Lansing, MI 48824 (United States); Department of Physics, Michigan State University, East Lansing, MI 48824 (United States); Baumann, T.; Bazin, D. [National Superconducting Cyclotron Laboratory, East Lansing, MI 48824 (United States); Brown, J. [Department of Physics, Wabash College, Crawfordsville, IN 47933 (United States); DeYoung, P.A. [Department of Physics, Hope College, Holland, MI 49422 (United States); Frank, N. [Department of Physics and Astronomy, Augustana College, Rock Island, IL 61201 (United States); Jones, M.D. [National Superconducting Cyclotron Laboratory, East Lansing, MI 48824 (United States); Department of Physics, Michigan State University, East Lansing, MI 48824 (United States); Kohley, Z. [National Superconducting Cyclotron Laboratory, East Lansing, MI 48824 (United States); Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Luther, B. [Department of Physics, Concordia College, Moorhead, MN 56562 (United States); Marks, B. [Department of Physics, Hope College, Holland, MI 49422 (United States); Spyrou, A. [National Superconducting Cyclotron Laboratory, East Lansing, MI 48824 (United States); Department of Physics, Michigan State University, East Lansing, MI 48824 (United States); Stephenson, S.L. [Department of Physics, Gettysburg College, Gettysburg, PA 17325 (United States); Thoennessen, M. [National Superconducting Cyclotron Laboratory, East Lansing, MI 48824 (United States); Department of Physics, Michigan State University, East Lansing, MI 48824 (United States); Volya, A. [Department of Physics, Florida State University, Tallahassee, FL 32306 (United States)

    2016-11-15

    The decay of unbound excited {sup 11}Li was measured after being populated by a two-proton removal from a {sup 13}B beam at 71 MeV/nucleon. Decay energy spectra and Jacobi plots were obtained from measurements of the momentum vectors of the {sup 9}Li fragment and neutrons. A resonance at an excitation energy of ∼1.2 MeV was observed. The kinematics of the decay are equally well fit by a simple dineutron-like model or a phase-space model that includes final state interactions. A sequential decay model can be excluded.

  8. Neutron correlations in the decay of the first excited state of "1"1Li

    International Nuclear Information System (INIS)

    Smith, J.K.; Baumann, T.; Bazin, D.; Brown, J.; DeYoung, P.A.; Frank, N.; Jones, M.D.; Kohley, Z.; Luther, B.; Marks, B.; Spyrou, A.; Stephenson, S.L.; Thoennessen, M.; Volya, A.

    2016-01-01

    The decay of unbound excited "1"1Li was measured after being populated by a two-proton removal from a "1"3B beam at 71 MeV/nucleon. Decay energy spectra and Jacobi plots were obtained from measurements of the momentum vectors of the "9Li fragment and neutrons. A resonance at an excitation energy of ∼1.2 MeV was observed. The kinematics of the decay are equally well fit by a simple dineutron-like model or a phase-space model that includes final state interactions. A sequential decay model can be excluded.

  9. Study of multi-neutron emission in the $\\beta$-decay of $^{11}$Li

    CERN Multimedia

    A new investigation of neutron emission in the $\\beta$-decay of $^{11}$Li is proposed. The principal goal of this study will be to directly measure, for the first time for any system, two $\\beta$-delayed neutrons in coincidence and determine the energy and angular correlations. This will be possible using liquid scintillator detectors, capable of distinguishing between neutrons and ambient $\\gamma$ and cosmic-rays, coupled to a new digital electronics and acquisition system. In parallel, a considerably more refined picture of the single-neutron emission will be obtained.

  10. Gamma-ray lines from radiative dark matter decay

    International Nuclear Information System (INIS)

    Garny, Mathias; Ibarra, Alejandro; Tran, David; Weniger, Christoph

    2011-01-01

    The decay of dark matter particles which are coupled predominantly to charged leptons has been proposed as a possible origin of excess high-energy positrons and electrons observed by cosmic-ray telescopes PAMELA and Fermi LAT. Even though the dark matter itself is electrically neutral, the tree-level decay of dark matter into charged lepton pairs will generically induce radiative two-body decays of dark matter at the quantum level. Using an effective theory of leptophilic dark matter decay, we calculate the rates of radiative two-body decays for scalar and fermionic dark matter particles. Due to the absence of astrophysical sources of monochromatic gamma rays, the observation of a line in the diffuse gamma-ray spectrum would constitute a strong indication of a particle physics origin of these photons. We estimate the intensity of the gamma-ray line that may be present in the energy range of a few TeV if the dark matter decay interpretation of the leptonic cosmic-ray anomalies is correct and comment on observational prospects of present and future Imaging Cherenkov Telescopes, in particular the CTA

  11. Proton and neutron decay rates in conventional and supersymmetric guts

    International Nuclear Information System (INIS)

    Salati, P.; Wallet, J.C.

    1982-01-01

    We present a general calculation of the two body decay rates of the nucleon, for the most general form of four-fermion ΔB = ΔL operators, in the framework of the SU(6) non-relativistic quark model. We have applied our general formulas to Higgs mediated decays in conventional and in supersymmetric SU(5) models. Lower bounds upon, the exchanged particles masses are given. We point out that the hierarchies of branching ratios in decays mediated by Higgs bosons are different from those of gauge boson decay modes (in the former case, neutrinos modes are dominant). We give, in conclusion, an experimental way to distinguish non-supersymmetric GUTs from supersymmetric ones, if the nucleon decays via Higgs bosons

  12. Calculation of isodose curves from initial neutron radiation of a hypothetical nuclear explosion using Monte Carlo Method

    International Nuclear Information System (INIS)

    Medeiros, Marcos P.C.; Rebello, Wilson F.; Andrade, Edson R.; Silva, Ademir X.

    2015-01-01

    Nuclear explosions are usually described in terms of its total yield and associated shock wave, thermal radiation and nuclear radiation effects. The nuclear radiation produced in such events has several components, consisting mainly of alpha and beta particles, neutrinos, X-rays, neutrons and gamma rays. For practical purposes, the radiation from a nuclear explosion is divided into i nitial nuclear radiation , referring to what is issued within one minute after the detonation, and 'residual nuclear radiation' covering everything else. The initial nuclear radiation can also be split between 'instantaneous or 'prompt' radiation, which involves neutrons and gamma rays from fission and from interactions between neutrons and nuclei of surrounding materials, and 'delayed' radiation, comprising emissions from the decay of fission products and from interactions of neutrons with nuclei of the air. This work aims at presenting isodose curves calculations at ground level by Monte Carlo simulation, allowing risk assessment and consequences modeling in radiation protection context. The isodose curves are related to neutrons produced by the prompt nuclear radiation from a hypothetical nuclear explosion with a total yield of 20 KT. Neutron fluency and emission spectrum were based on data available in the literature. Doses were calculated in the form of ambient dose equivalent due to neutrons H*(10) n - . (author)

  13. Calculation of isodose curves from initial neutron radiation of a hypothetical nuclear explosion using Monte Carlo Method

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Marcos P.C.; Rebello, Wilson F.; Andrade, Edson R., E-mail: rebello@ime.eb.br, E-mail: daltongirao@yahoo.com.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear; Silva, Ademir X., E-mail: ademir@nuclear.ufrj.br [Corrdenacao dos Programas de Pos-Graduacao em Egenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2015-07-01

    Nuclear explosions are usually described in terms of its total yield and associated shock wave, thermal radiation and nuclear radiation effects. The nuclear radiation produced in such events has several components, consisting mainly of alpha and beta particles, neutrinos, X-rays, neutrons and gamma rays. For practical purposes, the radiation from a nuclear explosion is divided into {sup i}nitial nuclear radiation{sup ,} referring to what is issued within one minute after the detonation, and 'residual nuclear radiation' covering everything else. The initial nuclear radiation can also be split between 'instantaneous or 'prompt' radiation, which involves neutrons and gamma rays from fission and from interactions between neutrons and nuclei of surrounding materials, and 'delayed' radiation, comprising emissions from the decay of fission products and from interactions of neutrons with nuclei of the air. This work aims at presenting isodose curves calculations at ground level by Monte Carlo simulation, allowing risk assessment and consequences modeling in radiation protection context. The isodose curves are related to neutrons produced by the prompt nuclear radiation from a hypothetical nuclear explosion with a total yield of 20 KT. Neutron fluency and emission spectrum were based on data available in the literature. Doses were calculated in the form of ambient dose equivalent due to neutrons H*(10){sub n}{sup -}. (author)

  14. $\\beta$-delayed neutron spectroscopy of $^{130-132}$ Cd isotopes with the ISOLDE decay station and the VANDLE array

    CERN Multimedia

    We propose to use the new ISOLDE decay station and the neutron detector VANDLE to measure the $\\beta$-delayed neutron emission of N=82-84 $^{130-132}$Cd isotopes. The large delayed neutron emission probability observed in a previous ISOLDE measurement is indicative of the Gamow-Teller transitions due to the decay of deep core neutrons. Core Gamow-Teller decay has been experimentally proven in the $^{78}$Ni region for the N>50 nuclei using the VANDLE array. The spectroscopic measurement of delayed neutron emission along the cadmium isotopic chain will allow us to track the evolution of the single particle states and the shell gap.

  15. Test of scalar meson structure in φ radiative decays

    International Nuclear Information System (INIS)

    Kumano, S.

    1992-12-01

    We show that φ radiative decays into scalar mesons [f 0 (975), a 0 (980) ≡ S] can provide important clues on the internal structures of these mesons. Radiative decay widths vary widely: B.R. = 10 -4 -10 -6 depending on the substructures (qq-bar, qqq-barq-bar, KK-bar, glueball). Hence, we could discriminate among various models by measuring these widths at future φ factories. The understanding of these meson structures is valuable not only in hadron spectroscopy but also in nuclear physics in connection with the widely-used but little-understood σ meson. We also find that the decay φ→S γ →K 0 K-bar 0 γ is not strong enough to pose a significant background problem for studying CP violation via φ→K 0 K-bar 0 at the φ factories. (author)

  16. Reference neutron radiations. Part 1: Characteristics and methods of production

    International Nuclear Information System (INIS)

    2001-01-01

    ISO 8529 consists of the following parts, under the general title Reference neutron radiations: Part 1: Characteristics and methods of production; Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field; Part 3: Calibration of area and personal dosimeters and determination of response as a function of energy and angle of incidence. This Part 1. of ISO 8529 specifies the reference neutron radiations, in the energy range from thermal up to 20 MeV, for calibrating neutron-measuring devices used for radiation protection purposes and for determining their response as a function of neutron energy. Reference radiations are given for neutron fluence rates of up to 1x10 9 m 2 s-1 , corresponding, at a neutron energy of 1 MeV, to dose-equivalent rates of up to 100 mSv h -1 . This part of ISO 8529 is concerned only with the methods of producing and characterizing the neutron reference radiations. The procedures for applying these radiations for calibrations are described in ISO 8529-2 and ISO 8529-3. The reference radiations specified are the following: neutrons from radionuclide sources, including neutrons from sources in a moderator; neutrons produced by nuclear reactions with charged particles from accelerators; neutrons from reactors. In view of the methods of production and use of them, these reference radiations are divided, for the purposes of this part of ISO 8529, into the following two separate sections. In clause 4, radionuclide neutron sources with wide spectra are specified for the calibration of neutron measuring devices. These sources should be used by laboratories engaged in the routine calibration of neutron-measuring devices, the particular design of which has already been type tested. In clause 5, accelerator-produced monoenergetic neutrons and reactor-produced neutrons with wide or quasi monoenergetic spectra are specified for determining the response of neutron-measuring devices

  17. Portable neutron and gamma-radiation instruments

    International Nuclear Information System (INIS)

    Murray, W.S.; Butterfield, K.B.

    1990-01-01

    This paper reports on the design and building of a smart neutron and gamma-radiation detection systems with embedded microprocessors programmed in the FORTH language. These portable instruments can be battery-powered and can provide many analysis functions not available in most radiation detectors. Local operation of the instruments is menu-driven through a graphics liquid crystal display and hex keypad; remote operation is through a serial communications link. While some instruments simply count particles, others determine the energy of the radiation as well as the intensity. The functions the authors have provided include absolute source-strength determination. Feynmann variance analysis, sequential-probability ratio test, and time-history recording

  18. Radiation sensitivity of food decay fungi

    International Nuclear Information System (INIS)

    Chang, H.G.; Lee, B.H.

    1980-01-01

    Five species of food decay fungi, Aspergillus flavus, Asp. uiger, Penicillium sp., Botrytis cinerea and Rhizopus stolonifer, were examined for their radiosensitivity in several suspension media. Asp. flavus, Asp. niger and Penicillium sp. have almost the same sensitivity toward gamma rays, with D value in the range of 30 to 35 K rad, whereas Botrytis cinerea has a D value of approximately 55 K rad and Rhizopus stolonifer, the most resistant fungus studied, has a D value of approximately 100 K rad. Dry spores of Asp. flavus showed a considerable increase in their radioresistance when compared with spores irradiated in water. Asp. flavus and Penicillium sp. spores irradiated in citrate buffer at pH 3-7 showed almost no change in their radiosensitivity with pH, but Botrytis cinerea spores showed a distinct decrease in their radioresistance at pH 6 and 7. Penicillium sp. spores irradiated in sucrose solutions showed no significant change in their radioresistance. Botrytis cinerea spores displayed a higher radioresistance when they were irradiated in sucrose solution than in water. (author)

  19. The possible Bπ molecular state and its radiative decay

    Energy Technology Data Exchange (ETDEWEB)

    Ke, Hong-Wei; Gao, Lei [Tianjin University, School of Science, Tianjin (China); Li, Xue-Qian [Nankai University, School of Physics, Tianjin (China)

    2017-05-15

    Recently, several exotic bosons have been confirmed as multi-quark states. However, there are violent disputes about their inner structures, namely if they are molecular states or tetraquarks, or even mixtures of the two structures. It would be interesting to search experimentally for non-strange four-quark states with open charm or bottom which are lighter than Λ{sub c} or Λ{sub b}. Reasonable arguments indicate that they are good candidates of pure molecular states Dπ or Bπ because pions are the lightest boson. Both Bπ and Dπ bound states do not decay via the strong interaction. The Bπ molecule may decay into B* by radiating a photon, whereas the Dπ molecule can only decay via weak interaction. In this paper we explore the mass spectra of the Bπ molecular states by solving the corresponding instantaneous B-S equation. Then the rate of radiative decay vertical stroke (3)/(2), (1)/(2) right angle → B*γ is calculated and our numerical results indicate that the processes can be measured by the future experiment. We also briefly discuss the Dπ case. Due to the constraint of the final state phase space it can only decay via weak interaction. (orig.)

  20. Study of the Iota in radiative J/PSI decays

    International Nuclear Information System (INIS)

    Richman, J.D.

    1985-01-01

    An analysis of the production, decay, and quantum numbers of the iota(1440) in radiative J/psi decays is presented. The iota(1440), because of its large production in this OZI-suppressed channel, is considered a possible gluonic bound-state, or glueball. The data, 2.7 x 10 6 produced J/psi's, were obtained using the Mark III detector at the SPEAR e + e - storage ring. The spin-parity of the iota(1440) is independently determined to be O - using two decays modes, iota → K/sub s/ 0 K/sup +/-/π/sup -/+/ and iota → K + K - π 0 . Measurements of the iota mass, width, and branching fractions are obtained using iota → K/sub s/ 0 K/sup +/-/π/sup -/+/, iota → K + K - π 0 , and iota → K/sub s/ 0 K/sub s/ 0 π 0 . The double radiative channels J/psi α γX, X → γ+ Vector, where Vector = rho 0 , phi, omega are studied to probe the quark content of the object X. Measurements of the hadronic decays J/psi → phi-eta, omega-eta, and omegaπ 0 , as well as the observation of the isospin-violating decay J/psi → rho 0 eta, are presented

  1. Estimation of delayed neutron emission probability by using the gross theory of nuclear β-decay

    International Nuclear Information System (INIS)

    Tachibana, Takahiro

    1999-01-01

    The delayed neutron emission probabilities (P n -values) of fission products are necessary in the study of reactor physics; e.g. in the calculation of total delayed neutron yields and in the summation calculation of decay heat. In this report, the P n -values estimated by the gross theory for some fission products are compared with experiment, and it is found that, on the average, the semi-gross theory somewhat underestimates the experimental P n -values. A modification of the β-decay strength function is briefly discussed to get more reasonable P n -values. (author)

  2. The effect of electromagnetic interactions on the proton spectrum in free neutron β-decay

    International Nuclear Information System (INIS)

    Bunatyan, G.G.

    2000-01-01

    In the β decay of an unpolarized free neutron, the effect of electromagnetic interactions on the proton recoil spectrum is studied in the light of the experiments which are carried out and planned for now. The corrections to the energy distribution of protons prove to amount to the value of a few per cent. Nowadays, this is substantial for obtaining with a high accuracy, of ∼ 1% or better, the characteristics of weak interactions by processing the data of the experiments on the proton distribution in the free neutron β-decay

  3. $^{11}$Be($\\beta$p), a quasi-free neutron decay?

    CERN Document Server

    Riisager, K.; Borge, M.J.G.; Briz, J.A.; Carmona-Gallardo, M.; Fraile, L.M.; Fynbo, H.O.U.; Giles, T.; Gottberg, A.; Heinz, A.; Johansen, J.G.; Jonson, B.; Kurcewicz, J.; Lund, M.V.; Nilsson, T.; Nyman, G.; Rapisarda, E.; Steier, P.; Tengblad, O.; Thies, R.; Winkler, S.R.

    2014-01-01

    We have observed $\\beta$-delayed proton emission from the neutron-rich nucleus $^{11}$Be by analysing a sample collected at the ISOLDE facility at CERN with accelerator mass spectrometry (AMS). With a branching ratio of (8.4 $\\pm$ 0.6)$\\times$ 10$^{-6}$ the strength of this decay mode, as measured by the B$_\\mathrm{GT}$-value, is unexpectedly high. The result is discussed within a simple single-particle model and could be interpreted as a quasi-free decay of the $^{11}$Be halo neutron into a single-proton state.

  4. Radiative decay rates in Si crystallites with a donor ion

    Science.gov (United States)

    Derbenyova, Natalia V.; Burdov, Vladimir A.

    2018-04-01

    Within the framework of the time-dependent density functional theory, the radiative recombination rates have been calculated for small, ˜1 nm in diameter, hydrogen-passivated silicon crystallites with a single lithium or phosphorus ion. Sharp increase of the radiative recombination rates with increasing temperature was revealed for the crystallites with the lithium ion. No temperature effect was found for the crystallites with the ion of P. It was also shown that the presence of ionized donors in Si crystallites can substantially accelerate the radiative decay compared to the case of pure crystallites.

  5. Λ(1520) → Λγ Radiative-Decay Width

    International Nuclear Information System (INIS)

    Vavilov, D.V.; Antipov, Yu.M.; Artamonov, A.V.; Batarin, V.A.; Victorov, V.A.; Golovkin, S.V.; Gorin, Yu.P.; Eroshin, O.V.; Kozhevnikov, A.P.; Konstantinov, A.S.; Kubarovsky, V.P.; Kurshetsov, V.F.; Landsberg, L.G.; Leontiev, V.M.; Molchanov, V.V.; Mukhin, V.A.; Patalakha, D.I.; Petrenko, S.V.; Petrukhin, A.I.; Kolganov, V.Z.

    2005-01-01

    The radiative decay Λ(1520) → Λγ was recorded in the exclusive reaction p + N → Λ(1520)K + + N at the SPHINX facility. The branching ratio for this decay and the corresponding partial width were found to be, respectively, Br[Λ(1520) → Λγ] = (1.02 ± 0.21) x 10 -2 and Γ[Λ(1520) → Λγ] = 159 ± 35 keV (the quoted errors are purely statistical, the systematic errors being within 15%)

  6. Gaugino radiative decay in an anomalous U(1)' model

    International Nuclear Information System (INIS)

    Lionetto, Andrea; Racioppi, Antonio

    2010-01-01

    We study the neutralino radiative decay into the lightest supersymmetric particle (LSP) in the framework of a minimal anomalous U(1) ' extension of the MSSM. It turns out that in a suitable decoupling limit the axino, which is present in the Stueckelberg multiplet, is the LSP. We compute the branching ratio (BR) for the decay of a neutralino into an axino and a photon. We find that in a wide region of the parameter space, the BR is higher than 93% in contrast with the typical value (≤1%) in the CMSSM.

  7. Radiation protection commissioning of neutron beam instruments at the OPAL research reactor

    International Nuclear Information System (INIS)

    Parkes, Alison; Saratsopoulos, John; Deura, Michael; Kenny, Pat

    2008-01-01

    The neutron beam facilities at the 20 MW OPAL Research Reactor were commissioned in 2007 and 2008. The initial suite of eight neutron beam instruments on two thermal neutron guides, two cold neutron guides and one thermal beam port located at the reactor face, together with their associated shielding were progressively installed and commissioned according to their individual project plans. Radiation surveys were systematically conducted as reactor power was raised in a step-wise manner to 20 MW in order to validate instrument shielding design and performance. The performance of each neutron guide was assessed by neutron energy spectrum and flux measurements. The activation of beam line components, decay times assessments and access procedures for Bragg Institute beam instrument scientists were established. The multiple configurations for each instrument and the influence of operating more than one instrument or beamline simultaneously were also tested. Areas of interest were the shielding around the secondary shutters, guide shield and bunker shield interfaces and monochromator doors. The shielding performance, safety interlock checks, improvements, radiation exposures and related radiation protection challenges are discussed. This paper discusses the health physics experience of commissioning the OPAL Research Reactor neutron beam facilities and describes health physics results, actions taken and lessons learned during commissioning. (author)

  8. Decay constants and radiative decays of heavy mesons in light-front quark model

    International Nuclear Information System (INIS)

    Choi, Ho-Meoyng

    2007-01-01

    We investigate the magnetic dipole decays V→Pγ of various heavy-flavored mesons such as (D,D*,D s ,D s *,η c ,J/ψ) and (B,B*,B s ,B s *,η b ,Υ) using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum dependent form factors F VP (q 2 ) for V→Pγ* decays are obtained in the q + =0 frame and then analytically continued to the timelike region by changing q perpendicular to iq perpendicular in the form factors. The coupling constant g VPγ for real photon case is then obtained in the limit as q 2 →0, i.e. g VPγ =F VP (q 2 =0). The weak decay constants of heavy pseudoscalar and vector mesons are also calculated. Our numerical results for the decay constants and radiative decay widths for the heavy-flavored mesons are overall in good agreement with the available experimental data as well as other theoretical model calculations

  9. Partial radiative capture of resonance neutrons

    International Nuclear Information System (INIS)

    Samour, C.

    1969-01-01

    The radiative capture of resonance neutrons has been studied near the Saclay linac between 0.5 and 700 eV with time-of-flight method and a Ge(Li) detector. 195 Pt + n and 183 W + n allow the study of the distribution of partial radiative widths and their eventual correlation and also the variation of γ i > with E γ . The mean values of Ml and El transition intensities are compared in several tin isotopes. Interference effects, either between resonances or between direct capture and resonant capture are found in 195 Pt + n, 197 Au + n and 59 Co + n. The excited level schemes of a great deal of nuclei are obtained and compared with theoretical predictions. This study has been completed by an analysis of thermal spectrum. (author) [fr

  10. Rearrangement of valence neutrons in the neutrinoless double-β decay of 136Xe

    Science.gov (United States)

    Szwec, S. V.; Kay, B. P.; Cocolios, T. E.; Entwisle, J. P.; Freeman, S. J.; Gaffney, L. P.; Guimarães, V.; Hammache, F.; McKee, P. P.; Parr, E.; Portail, C.; Schiffer, J. P.; de Séréville, N.; Sharp, D. K.; Smith, J. F.; Stefan, I.

    2016-11-01

    A quantitative description of the change in ground-state neutron occupancies between 136Xe and 136Ba, the initial and final state in the neutrinoless double-β decay of 136Xe, has been extracted from precision measurements of the cross sections of single-neutron-adding and -removing reactions. Comparisons are made to recent theoretical calculations of the same properties using various nuclear-structure models. These are the same calculations used to determine the magnitude of the nuclear matrix elements for the process, which at present disagree with each other by factors of 2 or 3. The experimental neutron occupancies show some disagreement with the theoretical calculations.

  11. Filtered thermal neutron captured cross-sections measurements and decay heat calculations

    International Nuclear Information System (INIS)

    Son, Pham Ngoc; Tan, Vuong Huu

    2014-01-01

    Recently, a pure thermal neutron beam has been developed for neutron capture measurements based on the horizontal channel No.2 of the research reactor at the Nuclear Research Institute, Dalat. The original reactor neutron spectrum is transmitted through an optimal composition of Bi and Si single crystals for delivering a thermal neutron beam with Cadmium ratio (R cd ) of 420 and neutron flux (Φ th ) of 1.6x10 6 n/cm 2 .s. This thermal neutron beam has been applied for measurements of capture cross-sections for nuclide of 51 V, 55 Mn, 180 Hf and 186 W by the activation method relative to the standard reaction 197 Au(n,g) 198 Au. In addition to the activities of neutron capture cross-sections measurements, the study on nuclear decay heat calculations has been also considered to be developed at the Institute. Some results on calculation procedure and decay heat values calculated with update nuclear database for 235 U, 238 U, 239 Pu and 232 Th are introduced in this report. (author)

  12. Decay studies of neutron-deficient lawrencium isotopes

    International Nuclear Information System (INIS)

    Antalic, S.; Saro, S.; Streicher, B.; Venhart, M.; Hessberger, F.P.; Ackermann, D.; Heinz, S.; Kindler, B.; Kojouharov, I.; Lommel, B.; Mann, R.; Hofmann, S.; Kuusiniemi, P.; Leino, M.; Nishio, K.; Sulignano, B.

    2008-01-01

    The radioactive decay of the isotopes 254-256 Lr and their daughter products was investigated by means of α, prompt α-γ and delayed conversion electron-γ coincidence spectroscopy. The isotopes were produced using the reaction 48 Ca+ 209 Bi. (orig.)

  13. The dependence of radiation damage analysis on neutron dosimetry

    International Nuclear Information System (INIS)

    Goland, A.N.; Parkin, D.M.

    1977-01-01

    The characteristics of defect production in neutron spectra can be determined by utilizing neutron cross section data (e.g. ENDF/B), detailed neutron spectral data and radiation damage models. The combination of neutron cross section and spectral data is a fundamental starting point in applying damage models. Calculations using these data and damage models show that there are significant differences in the way defects are produced in various neutron spectra. Nonelastic events dominate the recoil energy distribution in high-energy neutron sources such as those based upon fusion and deuteron-breakup reactions. Therefore, high-energy neutron cross sections must be measured or calculated to supplement existing data files. Radiation damage models can then be used to further characterize the diverse neutron spectra

  14. Easy-to-use application programs for decay heat and delayed neutron calculations on personal computers

    Energy Technology Data Exchange (ETDEWEB)

    Oyamatsu, Kazuhiro [Nagoya Univ. (Japan)

    1998-03-01

    Application programs for personal computers are developed to calculate the decay heat power and delayed neutron activity from fission products. The main programs can be used in any computers from personal computers to main frames because their sources are written in Fortran. These programs have user friendly interfaces to be used easily not only for research activities but also for educational purposes. (author)

  15. Radiative corrections of semileptonic hyperon decays Pt. 1

    International Nuclear Information System (INIS)

    Margaritisz, T.; Szegoe, K.; Toth, K.

    1982-07-01

    The beta decay of free quarks is studied in the framework of the standard SU(2) x U(1) model of weak and electromagnetic interactions. The so-called 'weak' part of radiative corrections is evaluated to order α in one-loop approximation using a renormalization scheme, which adjusts the counter terms to the electric charge, and to the mass of the charged and neutral vector bosons, Msub(w) and Msub(o), respectively. The obtained result is, to a good approximation, equal with the 'weak' part of radiative corrections for the semileptonic decay of any hyperon. It is shown in the model that the methods, which work excellently in case of the 'weak' corrections, do not, in general, provide us with the dominant part of the 'photonic' corrections. (author)

  16. Average radiation weighting factors for specific distributed neutron spectra

    International Nuclear Information System (INIS)

    Ninkovic, M.M.; Raicevic, J.J.

    1993-01-01

    Spectrum averaged radiation weighting factors for 6 specific neutron fields in the environment of 3 categories of the neutron sources (fission, spontaneous fission and (α,n)) are determined in this paper. Obtained values of these factors are greater 1.5 to 2 times than the corresponding quality factors used for the same purpose until a few years ago. This fact is very important to have in mind in the conversion of the neutron fluence into the neutron dose equivalent. (author)

  17. 21 CFR 892.5300 - Medical neutron radiation therapy system.

    Science.gov (United States)

    2010-04-01

    ... therapy system. (a) Identification. A medical neutron radiation therapy system is a device intended to... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical neutron radiation therapy system. 892.5300... analysis and display equipment, patient and equipment support, treatment planning computer programs...

  18. Measurement of the Decay of Thermal Neutrons in Water Poisoned with the Non-1/v Neutron Absorber Cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, L G; Moeller, E

    1968-01-15

    Measurements have been made of the decay constant of thermal neutrons in water poisoned with the non-1/v absorber cadmium. An experimental method has been used in which proper spatial integration of the neutron flux enables data, representative of the infinite medium to be accumulated without waiting for the establishment of a fundamental mode distribution. The change in effective cross section with concentration of the dissolved cadmium, d{sigma}{sub eff}/dN. has been determined for infinite medium at 20 deg C. Two- and three parameter fits of the decay constant yield -(0.32 {+-} 0.09) x 10{sup -17} barn cm{sup 3} and -(0.47 {+-} 0.10) x 10{sup -17} barn cm{sup 3}, respectively. Earlier published measurements have resulted in two to five times larger values, whereas a published calculated value of Nelkin's model is - 0.33 x 10{sup -17} barn cm{sup 3}.

  19. Measurement of the Decay of Thermal Neutrons in Water Poisoned with the Non-1/v Neutron Absorber Cadmium

    International Nuclear Information System (INIS)

    Larsson, L.G.; Moeller, E.

    1968-01-01

    Measurements have been made of the decay constant of thermal neutrons in water poisoned with the non-1/v absorber cadmium. An experimental method has been used in which proper spatial integration of the neutron flux enables data, representative of the infinite medium to be accumulated without waiting for the establishment of a fundamental mode distribution. The change in effective cross section with concentration of the dissolved cadmium, dσ eff /dN. has been determined for infinite medium at 20 deg C. Two- and three parameter fits of the decay constant yield -(0.32 ± 0.09) x 10 -17 barn cm 3 and -(0.47 ± 0.10) x 10 -17 barn cm 3 , respectively. Earlier published measurements have resulted in two to five times larger values, whereas a published calculated value of Nelkin's model is - 0.33 x 10 -17 barn cm 3

  20. Radiative decay of the bottom quark and the WWγ coupling

    International Nuclear Information System (INIS)

    Chia Swee Ping.

    1989-11-01

    The flavour-changing radiative decay b → sγ is analysed, and is found to be sensitive to the WWγ coupling. QCD corrections are found to play an important role. A good measurement of the branching ratio for B → K deg. γ may allow us to test the gauge coupling for WWγ of the Standard Model. (author). 45 refs, 8 figs, 1 tab

  1. On the spontaneous radiative decay of a moving atom

    International Nuclear Information System (INIS)

    Voitkiv, A B; Najjari, B; Ullrich, J

    2007-01-01

    We consider the relationship between the spontaneous radiative decay of an atom at rest and of an atom moving with a constant velocity. Based on the relativistic form, A μ j μ , of the field-current interaction we analyse two situations. In the first of them the radiative decay of a single atom is considered by using two different reference frames. In the second, a single reference frame is used to describe the radiative decay of two identical atoms, one of which is at rest in this frame and the other one moves with a constant velocity. Although in special relativity only the relative velocity between a source and an observer matters, there are subtle differences in the analysis of these situations: within the framework of the first situation one deals only with the Lorentz transformation, which is insensitive to whether exact or approximate atomic wave functions are used in the analysis, whereas the analysis of the second situation involves a gauge transformation which in general is not compatible with using approximate atomic wave functions. We have also shown that this gauge transformation can be used as a test for the accuracy of approximate atomic states obtained in atomic structure calculations

  2. aCORN: An experiment to measure the electron-antineutrino correlation in neutron decay

    Energy Technology Data Exchange (ETDEWEB)

    Wietfeldt, F.E., E-mail: few@tulane.ed [Department of Physics, Tulane University, New Orleans, LA 70118 (United States); Byrne, J. [University of Sussex (United Kingdom); Collett, B. [Physics Department, Hamilton College, Clinton, NY 13323 (United States); Dewey, M.S. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Jones, G.L. [Physics Department, Hamilton College, Clinton, NY 13323 (United States); Komives, A. [Physics Department, DePauw University, Greencastle, IN 46135 (United States); Laptev, A. [Department of Physics, Tulane University, New Orleans, LA 70118 (United States); Nico, J.S. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Noid, G.; Stephenson, E.J. [Indiana University Cyclotron Facility, Bloomington, IN 47408 (United States); Stern, I.; Trull, C. [Department of Physics, Tulane University, New Orleans, LA 70118 (United States); Yerozolimsky, B.G. [Physics Department, Harvard University, Cambridge, MA 02139 (United States)

    2009-12-11

    The aCORN experiment is designed to make a precision (<1%) measurement of the electron-antineutrino angular correlation (a-coefficient) in neutron beta decay. It uses a new method proposed in 1996 by Yerozolimsky and Mostovoy. Electrons and recoil protons from neutron decay in a cold beam are detected in coincidence. The momenta of the particles are selected so that the protons form two kinematically distinct time-of-flight groups as a function of electron energy. The count rate asymmetry in these two groups is proportional to the a-coefficient. Precision spectroscopy of the protons is not required. The apparatus is currently under construction. It will be integrated and tested at the Indiana University Cyclotron Facility (IUCF) and then moved to the NIST Center for Neutron Research for the initial physics run.

  3. Prompt neutron decay constant estimation of RSG-GAS at high power noise experiment

    International Nuclear Information System (INIS)

    Jujuratisbela, U.; Kristedjo; Tukiran; Pinem, S.; Iman, J.; Puryono; Sanjaya, A.; Suwarno

    1998-01-01

    The determination of prompt neutron decay constant (α) of RGS-GAS by using low power noise experiment method at the equilibrium core indicated that the result is not good. The bad result was due to the small ratio of the noise signal to background which was caused by low detector efficiency or contaminated core after long time operation. To solve the problem is tried by using noise experiment technique at high power. The voltage output of neutron detectors at power of 5, 12, and 23 MW were connected to preamplifier and filter then to the Dynamic Signal Analyzer Version-2 and then the power spectral density of each channel of JKT04 and JKT03, the cut off frequency of each channel can be determined by using linear regression technique such that the prompt neutron decay constant can be estimated

  4. Prompt neutron decay constants and subcritical measurements for material control and accountability in SHEBA

    International Nuclear Information System (INIS)

    Sanchez, R.; Jaegers, P.

    1998-01-01

    Rossi-Alpha measurements were performed on the SHEBA assembly to determine the prompt neutron decay constants. These prompt neutron decay constants represent an eigenvalue characteristic of this particular assembly, which can be used to infer the amount of fissile material in the assembly. In addition, subcritical measurements using Rossi-Alpha and the source-jerk techniques were also performed on the SHEBA assembly. These measurements were compared against TWODANT calculations and agreed quite well. The subcritical measurements were also used to obtain a unique signature that represented the amount of material associated with the degree of subcriticality of the SHEBA assembly. Finally, the Feynman variance-to-mean technique in conjunction with TWODANT, were used to determine the effective delayed neutron fraction for the SHEBA assembly

  5. A search for narrow states in radiative upsilon decays

    International Nuclear Information System (INIS)

    Lowe, S.T.

    1986-12-01

    A search for new states produced in radiative Υ(1S) decays is accomplished by observing the inclusive photon energy spectrum. A narrow resonance in the energy spectrum indicates the existence of a new state X produced by the process Υ → γX. The analysis is based on approximately 0.44 x 10 6 Υ(1S) events produced at the DORIS II e + e - storage ring. These data were collected with the Crystal Ball detector between April 1983 and May 1986. This analysis finds no evidence for a new state, so upper limits on the branching ratio BR(Υ → γX) are derived, assuming the state X decays primarily to high-multiplicity hadronic final states. In particular, if the state X were a minimal Higgs particle, its primary decay mode would be to the heaviest fermion-antifermion pair energetically available. For the radiative Υ(1S) decays studied here, the heavy fermions would be c anti c or s anti s quark states, over most of the relevant Higgs' mass range. The resulting upper limit for BR(Υ(1S) → γX) is highly energy dependent but for X mass between 1.5 GeV and 8.0 GeV, the 90% confidence level upper limit is better than 8.0 x 10 -4 . For a Higgs' mass near 5.0 GeV, the upper limit is about 2.0 x 10 -4 which is approximately equal to the lowest order calculation for the Wilczek mechanism. The Wilczek calculation with QCD radiative corrections predict branching ratios below the limits set here for all Higgs' masses

  6. Development of advanced radiation monitors for pulsed neutron fields

    CERN Document Server

    AUTHOR|(CDS)2081895

    The need of radiation detectors capable of efficiently measuring in pulsed neutron fields is attracting widespread interest since the 60s. The efforts of the scientific community substantially increased in the last decade due to the increasing number of applications in which this radiation field is encountered. This is a major issue especially at particle accelerator facilities, where pulsed neutron fields are present because of beam losses at targets, collimators and beam dumps, and where the correct assessment of the intensity of the neutron fields is fundamental for radiation protection monitoring. LUPIN is a neutron detector that combines an innovative acquisition electronics based on logarithmic amplification of the collected current signal and a special technique used to derive the total number of detected neutron interactions, which has been specifically conceived to work in pulsed neutron fields. Due to its special working principle, it is capable of overcoming the typical saturation issues encountere...

  7. Alpha decay and cluster decay of some neutron-rich actinide nuclei

    Indian Academy of Sciences (India)

    2017-02-09

    Feb 9, 2017 ... Abstract. Nuclei in the actinide region are good in exhibiting cluster radioactivity. In the present work, the half-lives of α-decay and heavy cluster emission from certain actinide nuclei have been calculated using cubic plus Yukawa plus exponential model (CYEM). Our model has a cubic potential for the ...

  8. Calculation of radioactive decay chains produced by neutron irradiation

    International Nuclear Information System (INIS)

    Ponti, C.

    1984-01-01

    The calculation of the decay chains of radioactive isotopes may be solved by different computer codes that apply similar numerical methods. Analytical forms of solution of this problem are known since a long time, but their implementation has always been hindered by the possible occurrence of large numerical errors or by the need, to avoid them, of very high numerical precision. In this paper the reason of these difficulties has been pointed out and solved. In particular a new family of mathematical identities has been found

  9. Neutron spectrometry by diamond detector for nuclear radiation

    International Nuclear Information System (INIS)

    Kozlov, S.F.; Konorova, E.A.; Barinov, A.L.; Jarkov, V.P.

    1975-01-01

    Experiments on fast neutron spectrometry using the nuclear radiation diamond detector inside a horizontal channel of a water-cooled and water-moderated reactor are described. It is shown that the diamond detector enables neutron spectra to be measured within the energy range of 0.3 to 10 MeV against reactor gamma-radiation background and has radiation resistance higher than that of conventional semiconductor detectors. (U.S.)

  10. Factorization for radiative heavy quarkonium decays into scalar Glueball

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ruilin [INPAC, Shanghai Key Laboratory for Particle Physics and Cosmology,Department of Physics and Astronomy, Shanghai Jiao Tong University,Dongchuan RD 800, Shanghai 200240 (China); State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics, Chinese Academy of Sciences,Zhongguancun E. St. 55, Beijing 100190 (China); CAS Center for Excellence in Particle Physics,Institute of High Energy Physics, Chinese Academy of Sciences,Yuquan RD 19B, Beijing 100049 (China)

    2015-09-24

    We establish the factorization formula for scalar Glueball production through radiative decays of vector states of heavy quarkonia, e.g. J/ψ, ψ(2S) and Υ(nS), where the Glueball mass is much less than the parent heavy quarkonium mass. The factorization is demonstrated explicitly at one-loop level through the next-to-leading order (NLO) corrections to the hard kernel, the non-relativistic QCD (NRQCD) long-distance matrix elements (LDMEs) of the heavy quarkonium, and the light-cone distribution amplitude (LCDA) of scalar Glueball. The factorization provides a comprehensive theoretical approach to investigate Glueball production in the radiative decays of vector states of heavy quarkonia and determine the physic nature of Glueball. We discuss the scale evolution equation of LCDA for scalar Glueball. In the end, we extract the value of the decay constant of Scalar Glueball from Lattice QCD calculation and analyze the mixing effect among f{sub 0}(1370), f{sub 0}(1500) and f{sub 0}(1710).

  11. Measurement of free neutron lifetime by electron decay detection with a migration chamber

    International Nuclear Information System (INIS)

    Grivot, P.

    1988-01-01

    In this study, the different aspects of the realization of the experimental setup are successively described: creation of a pulsed monochromatic neutron beam, design and construction of a detector for neutron decay electrons, development of electronics and of the data acquisition system, measurement of the helium-3 density in a gaseous mixture. A mechanical system called double chopper and a monochromator crystal are used to obtain neutron bursts with a length of about 28 cm and a velocity of 846 m/s. The electron detector is a time projection chamber (TPC) filled at atmospheric pressure with a helium-4 (93%), helium-3 (10 -5 %) and carbon dioxide (7%) mixture. The problems encountered during the data acquisition with the neutron beam and preliminary results from analysis are also presented [fr

  12. Measurement of neutrino and proton asymmetry in the decay of polarized neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, M.

    2007-05-09

    The Standard Model of Particle Physics is in excellent agreement with all experimental results. However, it is not believed to be the most fundamental theory. It requires, for example, too many free parameters and is not able to explain the existence of effects such as parity-violation or CP-violation. Thus measurements have to be performed to probe the Standard Model and to search for ''new physics''. An ideal laboratory for this is the decay of the free polarized neutron. In this thesis, we present measurements of the neutrino asymmetry B and the proton asymmetry C in neutron decay. These coefficients describe the correlation between neutron spin and momentum of the respective particle, and provide detailed information on the structure of the underlying theory. The experiment was performed using the electron spectrometer PERKEO II installed at the Institut Laue-Langevin (ILL). It was equipped with a combined electron-proton detector to reconstruct the neutrino in a coincidence measurement. The uncertainty of our neutrino asymmetry result, B=0.9802(50), is comparable to the present best measurement, and, for the first time ever, we obtained a precise value for the proton asymmetry, C=-0.2377(36). Both results are used to analyze neutron decay for hints on ''Physics beyond the Standard Model'' by studying possible admixtures of right-handed currents and of scalar and tensor couplings to the interaction. (orig.)

  13. Measurement of neutrino and proton asymmetry in the decay of polarized neutrons

    International Nuclear Information System (INIS)

    Schumann, M.

    2007-01-01

    The Standard Model of Particle Physics is in excellent agreement with all experimental results. However, it is not believed to be the most fundamental theory. It requires, for example, too many free parameters and is not able to explain the existence of effects such as parity-violation or CP-violation. Thus measurements have to be performed to probe the Standard Model and to search for ''new physics''. An ideal laboratory for this is the decay of the free polarized neutron. In this thesis, we present measurements of the neutrino asymmetry B and the proton asymmetry C in neutron decay. These coefficients describe the correlation between neutron spin and momentum of the respective particle, and provide detailed information on the structure of the underlying theory. The experiment was performed using the electron spectrometer PERKEO II installed at the Institut Laue-Langevin (ILL). It was equipped with a combined electron-proton detector to reconstruct the neutrino in a coincidence measurement. The uncertainty of our neutrino asymmetry result, B=0.9802(50), is comparable to the present best measurement, and, for the first time ever, we obtained a precise value for the proton asymmetry, C=-0.2377(36). Both results are used to analyze neutron decay for hints on ''Physics beyond the Standard Model'' by studying possible admixtures of right-handed currents and of scalar and tensor couplings to the interaction. (orig.)

  14. Does fast-neutron radiotherapy merely reduce the radiation dose

    International Nuclear Information System (INIS)

    Ando, Koichi

    1984-01-01

    We examined whether fast-neutron radiotherapy is superior to low-LET radiotherpy by comparing the relationship between cell survival and tumor control probabilities after exposure of tumor-bearing (species) to the two modalities. Analysis based on TCD 50 assay and lung colony assay indicated that single dose of fast neutron achieved animal cures at higher survival rates than other radiation modalities including single and fractionated γ-ray doses, fractionated doses of fast neutron, and the mixed-beam scheme with a sequence of N-γ-γ-γ-N. We conclude that fast-neutron radiotherapy cured animal tumors with lower cell killing rates other radiation modalities. (author)

  15. Radiation damage of pixelated photon detector by neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Isamu [KEK, 1-1 Oho Tsukuba 305-0801 (Japan)], E-mail: isamu.nakamura@kek.jp

    2009-10-21

    Radiation Damage of Pixelated Photon Detector by neutron irradiation is reported. MPPC, one of PPD or Geiger-mode APD, developed by Hamamatsu Photonics, is planned to be used in many high energy physics experiments. In such experiments radiation damage is a serious issue. A series of neutron irradiation tests is performed at the Reactor YAYOI of the University of Tokyo. MPPCs were irradiated at the reactor up to 10{sup 12}neutron/cm{sup 2}. In this paper, the effect of neutron irradiation on the basic characteristics of PPD including gain, noise rate, photon detection efficiency is presented.

  16. Determination of prompt neutron decay constant of the AP-600 reactor core

    International Nuclear Information System (INIS)

    Surbakti, T.

    1998-01-01

    Determination of prompt neutron decay constant of the AP-600 reactor core has been performed using combination of two codes WIMS/D4 and Batan-2DIFF. The calculation was done at beginning of cycle and all of control rods pulled out. Cell generation from various kinds of core materials was done with 4 neutron energy group in 1-D transport code (WIMS/D4). The cell is considered for 1/4 fuel assembly in cluster model with square pitch arrange and then, the dimension of its unit cell is calculated. The unit cell consist of a fuel and moderator unit. The unit cell dimension as input data of WIMS/D4 code, called it annulus, is obtained from the equivalent unit cell. Macroscopic cross sections as output was used as input on neutron diffusion code Batan-2DIFF for core calculation as appropriate with three enrichment regions of the fuel of AP-600 core, namely 2, 2.5, and 3%. From result of diffusion code ( Batan-2DIFF) is obtained the value of delayed neutron fraction of 6.932E-03 and average prompt neutron life-time of 26.38 μs, so that the value of prompt neutron decay constant is 262.8 s-1. If it is compared the calculation result with the design value, the deviation are, for the design value of delayed neutron fraction is 7.5E-03, about 8% and the design value of average prompt neutron life time is 19.6 μs, about 34% respectively. The deviation because there are still unknown several core components of AP-600, so it didn't include in calculation yet

  17. Search for charmless decays of B hadrons in hadronic and radiative (b --> s gamma) decay modes using the DELPHI detector

    CERN Document Server

    Liko, Dietrich

    1995-01-01

    Charmless decays of B hadrons have been of considerable interest during the last years. Decays in hadronic modes proceed either trough tree level b � u transitions or loop diagrams involving so-called "hadronic" penguins. Tree level dominated decays confirm the non zero value of JVubl in the CKM mixing matrix while those induced by penguin processes provide tests of the loop structure of the Standard Model. Decays in the radiative modes b -+ s-y are forbidden at tree level and proceed only trough loop diagrams. Possible contributions to the decay rate due to new physics provide a test of the Standard Model. During the last years various measurements of decay rates have been performed at colliders at the bb-threshold. Experiments at the LEP collider have already collected sufficient data to study these decays in a different experimental environment. Results of searches at the DELPHI experiment are presented.

  18. Radiative corrections in K{yields}3{pi} decays

    Energy Technology Data Exchange (ETDEWEB)

    Bissegger, M. [Institute for Theoretical Physics, University of Bern, Sidlerstr. 5, CH-3012 Bern (Switzerland); Fuhrer, A. [Institute for Theoretical Physics, University of Bern, Sidlerstr. 5, CH-3012 Bern (Switzerland); Physics Department, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0319 (United States); Gasser, J. [Institute for Theoretical Physics, University of Bern, Sidlerstr. 5, CH-3012 Bern (Switzerland); Kubis, B. [Helmholtz-Institut fuer Strahlen-und Kernphysik, Universitaet Bonn, Nussallee 14-16, D-53115 Bonn (Germany)], E-mail: kubis@itkp.uni-bonn.de; Rusetsky, A. [Helmholtz-Institut fuer Strahlen-und Kernphysik, Universitaet Bonn, Nussallee 14-16, D-53115 Bonn (Germany)

    2009-01-01

    We investigate radiative corrections to K{yields}3{pi} decays. In particular, we extend the non-relativistic framework developed recently to include real and virtual photons and show that, in a well-defined power counting scheme, the results reproduce corrections obtained in the relativistic calculation. Real photons are included exactly, beyond the soft-photon approximation, and we compare the result with the latter. The singularities generated by pionium near threshold are investigated, and a region is identified where standard perturbation theory in the fine structure constant {alpha} may be applied. We expect that the formulae provided allow one to extract S-wave {pi}{pi} scattering lengths from the cusp effect in these decays with high precision.

  19. LHCb: Radiative decays of B hadrons at LHCb

    CERN Multimedia

    Soomro, F

    2009-01-01

    Flavour physics is an excellent probe of physics beyond the Standard Model. It offers the possibility to measure effects from heavy virtual particles with masses above the experimental reach in terms of direct production. LHCb is well positioned to exploit the large statistics of B hadrons available at LHC, to make competitive measurements in various radiative decays like B_d->K^{*} , B_s\\phi\\gamma, \\Lambda_b->\\Lambda ^{0\\gamma} and B^+->\\phiK^{+\\gamma}.. For example, the direct CP asymmetry in K^{*\\gamma} decay can be measured to the level of 1.8%[1], better than the current experimental accuracy, with only 100 pb-1of integrated luminosity.

  20. Spectroscopy of light neutron deficient nuclei: 31Ar and 27S decays

    International Nuclear Information System (INIS)

    Borrel, V.

    1991-01-01

    Light neutron-deficient nuclei exhibit several interesting decay modes. In some cases, beta-delayed alpha emission becomes possible, and beta-delayed three-proton emission can be allowed. The energy spectra of the emitted protons should give informations on the position of the isobaric analog state and on its deexcitation modes. Experimental results obtained at GANIL with the LISE spectrometer on the decay of the isotopes 31 Ar and 27 S are presented. These data are discussed and compared with the predicted isobaric analog state excitation energies and with shell-model calculations. (G.P.) 13 refs.; 7 figs.; 1 tab

  1. A Mott polarimeter for the search of time reversal violation in the decay of free neutrons

    International Nuclear Information System (INIS)

    Ban, G.; Beck, M.; Bialek, A.; Bodek, K.; Gorel, P.; Kirch, K.; Kistryn, St.; Kozela, A.; Kuzniak, M.; Lindroth, A.; Naviliat-Cuncic, O.; Pulut, J.; Severijns, N.; Stephan, E.; Zejma, J.

    2006-01-01

    A new polarimeter for low-energy electrons has been built and tested. The device was developed for the measurement of the transverse polarization of beta particles emitted in the decay of polarized cold neutrons. The decay electrons are identified by multi-wire proportional chambers made of low-Z materials and are detected with plastic scintillator hodoscopes. The transverse polarization is analyzed by means of large angle Mott scattering on a thin Pb foil. We describe here the elements of the apparatus and present the results of test measurements which illustrate its performance

  2. A Mott polarimeter for the search of time reversal violation in the decay of free neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Ban, G. [Laboratoire de Physique Corpusculaire, Caen (France); Beck, M. [Catholic University, Leuven (Belgium); Bialek, A. [Institute of Physics, Polish Academy of Sciences, Cracow (Poland); Bodek, K. [Institute of Physics, Jagiellonian University, Cracow (Poland)]. E-mail: ufbodek@if.uj.edu.pl; Gorel, P. [Laboratoire de Physique Corpusculaire, Caen (France); Paul Scherrer Institute, Villigen (Switzerland); Kirch, K. [Paul Scherrer Institute, Villigen (Switzerland); Kistryn, St. [Institute of Physics, Jagiellonian University, Cracow (Poland); Kozela, A. [Institute of Physics, Polish Academy of Sciences, Cracow (Poland); Kuzniak, M. [Institute of Physics, Jagiellonian University, Cracow (Poland); Lindroth, A. [Catholic University, Leuven (Belgium); Naviliat-Cuncic, O. [Laboratoire de Physique Corpusculaire, Caen (France); Pulut, J. [Institute of Physics, Jagiellonian University, Cracow (Poland); Paul Scherrer Institute, Villigen (Switzerland); Catholic University, Leuven (Belgium); Severijns, N. [Catholic University, Leuven (Belgium); Stephan, E. [Institute of Physics, University of Silesia, Katowice (Poland); Zejma, J. [Institute of Physics, Jagiellonian University, Cracow (Poland)

    2006-09-15

    A new polarimeter for low-energy electrons has been built and tested. The device was developed for the measurement of the transverse polarization of beta particles emitted in the decay of polarized cold neutrons. The decay electrons are identified by multi-wire proportional chambers made of low-Z materials and are detected with plastic scintillator hodoscopes. The transverse polarization is analyzed by means of large angle Mott scattering on a thin Pb foil. We describe here the elements of the apparatus and present the results of test measurements which illustrate its performance.

  3. β Decay in the Region of Neutron-deficient {sup 69,70,71}Kr

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, A.M., E-mail: ARogers@lbl.gov [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 (United States); Giovinazzo, J. [Centre d' Etudes Nucléaires de Bordeaux-Gradignan, Université Bordeaux 1, UMR 5797 CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175, Gardignan Cedex (France); Lister, C.J. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Blank, B.; Canchel, G. [Centre d' Etudes Nucléaires de Bordeaux-Gradignan, Université Bordeaux 1, UMR 5797 CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175, Gardignan Cedex (France); Clark, J.A. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); France, G. de; Grévy, S. [GANIL CEA/DSM-CNRS/IN2P3, Boulevard Henri Becquerel, BP55027, 14076 CEAN Cedex 5 (France); Gros, S.; McCutchan, E.A. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Oliveira Santos, F. de [GANIL CEA/DSM-CNRS/IN2P3, Boulevard Henri Becquerel, BP55027, 14076 CEAN Cedex 5 (France); Savard, G.; Seweryniak, D. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Stefan, I.; Thomas, J.-C. [GANIL CEA/DSM-CNRS/IN2P3, Boulevard Henri Becquerel, BP55027, 14076 CEAN Cedex 5 (France)

    2014-06-15

    Decay spectroscopy was performed for neutron-deficient nuclei ranging from zinc to krypton with isospin −3/2 ≤T{sub z}≤0. Measurements of correlated β-delayed protons allowed us to determine the isobaric analog states fed from the decay of {sup 65}Se and {sup 69}Kr, constraining the spin of the {sup 69}Kr ground state. Preliminary results regarding the half lives for the T{sub z}=−1 systems, relevant to the rapid proton capture (rp) process, are discussed.

  4. The CARDS array for neutron-rich decay spectroscopy at HRIBF

    CERN Document Server

    Batchelder, J C; Bingham, C R; Carter, H K; Cole, J D; Fong, D; Garrett, P E; Grzywacz, R; Hamilton, J H; Hartley, D J; Hwang, J K; Krolas, W; Kulp, D C; Larochelle, Y; Piechaczek, A; Ramayya, A V; Rykaczewski, K; Spejewski, E H; Stracener, D W; Tantawy, M N; Winger, J A; Wood, J; Zganjar, E F

    2003-01-01

    An array for decay studies of neutron-rich nuclei has been commissioned for use at the UNISOR separator at Holifield Radioactive Ion Beam Facility. This array consists of three segmented clover Ge detectors, plastic scintillators, and a high-resolution (approx 1 keV) Si conversion electron spectrometer. These detectors are mounted on a support that surrounds a moving tape collector. This system has been named clover array for radioactive decay studies. The detectors have been outfitted with digital flash ADCs (XIA DGFs) that fit the preamp signals, with built-in pileup rejection.

  5. The CARDS array for neutron-rich decay spectroscopy at HRIBF

    International Nuclear Information System (INIS)

    Batchelder, J.C.; Bilheux, J.-C.; Bingham, C.R.; Carter, H.K.; Cole, J.D.; Fong, D.; Garrett, P.E.; Grzywacz, R.; Hamilton, J.H.; Hartley, D.J.; Hwang, J.K.; Krolas, W.; Kulp, D.; Larochelle, Y.; Piechaczek, A.; Ramayya, A.V.; Rykaczewski, K.P.; Spejewski, E.H.; Stracener, D.W.; Tantawy, M.N.; Winger, J.A.; Wood, J.; Zganjar, E.F.

    2003-01-01

    An array for decay studies of neutron-rich nuclei has been commissioned for use at the UNISOR separator at Holifield Radioactive Ion Beam Facility. This array consists of three segmented clover Ge detectors, plastic scintillators, and a high-resolution (∼1 keV) Si conversion electron spectrometer. These detectors are mounted on a support that surrounds a moving tape collector. This system has been named clover array for radioactive decay studies. The detectors have been outfitted with digital flash ADCs (XIA DGFs) that fit the preamp signals, with built-in pileup rejection

  6. β decay and isomeric properties of neutron-rich Ca and Sc isotopes

    International Nuclear Information System (INIS)

    Crawford, H. L.; Mantica, P. F.; Berryman, J. S.; Stoker, J. B.; Janssens, R. V. F.; Carpenter, M. P.; Kay, B. P.; Lauritsen, T.; Zhu, S.; Broda, R.; Cieplicka, N.; Fornal, B.; Grinyer, G. F.; Minamisono, K.; Hoteling, N.; Stefanescu, I.; Walters, W. B.

    2010-01-01

    The isomeric and β-decay properties of neutron-rich 53-57 Sc and 53,54 Ca nuclei near neutron number N=32 are reported, and the low-energy level schemes of 53,54,56 Sc and 53-57 Ti are presented. The low-energy level structures of the 21 Sc isotopes are discussed in terms of the coupling of the valence 1f 7/2 proton to states in the corresponding 20 Ca cores. Implications with respect to the robustness of the N=32 subshell closure are discussed, as well as the repercussions for a possible N=34 subshell closure.

  7. First direct constraints on Fierz interference in free-neutron β decay

    Science.gov (United States)

    Hickerson, K. P.; Sun, X.; Bagdasarova, Y.; Bravo-Berguño, D.; Broussard, L. J.; Brown, M. A.-P.; Carr, R.; Currie, S.; Ding, X.; Filippone, B. W.; García, A.; Geltenbort, P.; Hoagland, J.; Holley, A. T.; Hong, R.; Ito, T. M.; Knecht, A.; Liu, C.-Y.; Liu, J. L.; Makela, M.; Mammei, R. R.; Martin, J. W.; Melconian, D.; Mendenhall, M. P.; Moore, S. D.; Morris, C. L.; Pattie, R. W.; Pérez Galván, A.; Picker, R.; Pitt, M. L.; Plaster, B.; Ramsey, J. C.; Rios, R.; Saunders, A.; Seestrom, S. J.; Sharapov, E. I.; Sondheim, W. E.; Tatar, E.; Vogelaar, R. B.; VornDick, B.; Wrede, C.; Young, A. R.; Zeck, B. A.; UCNA Collaboration

    2017-10-01

    Precision measurements of free-neutron β decay have been used to precisely constrain our understanding of the weak interaction. However, the neutron Fierz interference term bn, which is particularly sensitive to beyond-standard-model tensor currents at the TeV scale, has thus far eluded measurement. Here we report the first direct constraints on this term, finding bn=0.067 ±0 .005stat-0.061+0.090sys , consistent with the standard model. The uncertainty is dominated by absolute energy reconstruction and the linearity of the β spectrometer energy response.

  8. Absence of storage effects on radiation damage after thermal neutron irradiation of dry rice seeds

    Energy Technology Data Exchange (ETDEWEB)

    Kowyama, Y. [Mie Univ., Tsu (Japan); Saito, M.; Kawase, T.

    1987-09-15

    Storage effects on dry rice seeds equilibrated to 6.8% moisture content were examined after irradiation with X-rays of 5, 10, 20 and 40 kR and with thermal neutrons of 2.1, 4.2, 6.3 and 8.4×10{sup 13}N{sub th}/cm{sup 2}. Reduction in root growth was estimated from dose response curves after storage periods of 1 hr to 21 days. The longer the storage period, the greater enhancement of radiation damages in X-irradiated seeds. There were two components in the storage effect, i. e., a rapid increase of radiosensitivity within the first 24 hr and a slow increase up to 21 days. An almost complete absence of a storage effect was observed after thermal neutron exposure, in spite of considerably high radioactivities of the induced nuclides, {sup 56}Mn, {sup 42}K and {sup 24}Na, which were detected from gamma-ray spectrometry of the irradiated seeds. The present results suggest that the contributions of gamma-rays from the activated nuclides and of inherent contaminating gamma-rays are little or negligible against the neutron-induced damage, and that the main radiobiological effects of thermal neutrons are ascribed to in situ radiations, i, e., heavy particles resulting from neutron-capture reaction of atom. A mechanism underlying the absence of storage effect after thermal neutron irradiation was briefly discussed on the basis of radical formation and decay. (author)

  9. Beta-decay rate and beta-delayed neutron emission probability of improved gross theory

    Science.gov (United States)

    Koura, Hiroyuki

    2014-09-01

    A theoretical study has been carried out on beta-decay rate and beta-delayed neutron emission probability. The gross theory of the beta decay is based on an idea of the sum rule of the beta-decay strength function, and has succeeded in describing beta-decay half-lives of nuclei overall nuclear mass region. The gross theory includes not only the allowed transition as the Fermi and the Gamow-Teller, but also the first-forbidden transition. In this work, some improvements are introduced as the nuclear shell correction on nuclear level densities and the nuclear deformation for nuclear strength functions, those effects were not included in the original gross theory. The shell energy and the nuclear deformation for unmeasured nuclei are adopted from the KTUY nuclear mass formula, which is based on the spherical-basis method. Considering the properties of the integrated Fermi function, we can roughly categorized energy region of excited-state of a daughter nucleus into three regions: a highly-excited energy region, which fully affect a delayed neutron probability, a middle energy region, which is estimated to contribute the decay heat, and a region neighboring the ground-state, which determines the beta-decay rate. Some results will be given in the presentation. A theoretical study has been carried out on beta-decay rate and beta-delayed neutron emission probability. The gross theory of the beta decay is based on an idea of the sum rule of the beta-decay strength function, and has succeeded in describing beta-decay half-lives of nuclei overall nuclear mass region. The gross theory includes not only the allowed transition as the Fermi and the Gamow-Teller, but also the first-forbidden transition. In this work, some improvements are introduced as the nuclear shell correction on nuclear level densities and the nuclear deformation for nuclear strength functions, those effects were not included in the original gross theory. The shell energy and the nuclear deformation for

  10. Early reionization by decaying particles and cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Kasuya, S.; Kawasaki, M.

    2004-01-01

    We study the reionization scenario in which ionizing UV photons emitted from decaying particle, in addition to usual contributions from stars and quasars, ionize the universe. It is found that the scenario is consistent with both the first year data of the Wilkinson Microwave Anisotropy Probe and the fact that the universe is not fully ionized until z∼6 as observed by Sloan Digital Sky Survey. Likelihood analysis revealed that rather broad parameter space can be chosen. This scenario will be discriminated by future observations, especially by the EE polarization power spectrum of cosmic microwave background radiation

  11. Neutron radiation capture; Radiatsionnyj zakhvat nejtronov

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1987-12-31

    For all stable and experimentally studied radionuclides evaluated data are presented on cross sections of thermal neutrons, on resonance integrals and medium neutron cross sections with energy of 30 KeV. Refs, figs and tabs.

  12. $\\beta$-decay study of neutron-rich Tl and Pb isotopes

    CERN Multimedia

    It is proposed to study the structure of neutron-rich nuclei beyond $^{208}$Pb. The one-proton hole $^{211-215}$Tl and the semi magic $^{213}$Pb will be produced and studied via nuclear and atomic spectroscopy searching for long-lived isomers and investigating the $\\beta$-delayed $\\gamma$- emission to build level schemes. Information on the single particle structure in $^{211-215}$Pb, especially the position of the g$_{9/2}$ and i$_{11/2}$ neutron orbitals, will be extracted along with lifetimes. The $\\beta$-decay will be complemented with the higher spin selectivity that can be obtained by resonant laser ionization to single-out the decay properties of long-living isomers in $^{211,213}$Tl and $^{213}$Pb.

  13. Simulation analysis of radiation fields inside phantoms for neutron irradiation

    International Nuclear Information System (INIS)

    Satoh, Daiki; Takahashi, Fumiaki; Endo, Akira; Ohmachi, Y.; Miyahara, N.

    2007-01-01

    Radiation fields inside phantoms have been calculated for neutron irradiation. Particle and heavy-ion transport code system PHITS was employed for the calculation. Energy and size dependences of neutron dose were analyzed using tissue equivalent spheres of different size. A voxel phantom of mouse was developed based on CT images of an 8-week-old male C3H/HeNs mouse. Deposition energy inside the mouse was calculated for 2- and 10-MeV neutron irradiation. (author)

  14. Radioactive decay data tables: a handbook of decay data for application to radiation dosimetry and radiological assessments

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1982-01-01

    Reviews compendium containing recommended decay data for approx. 500 radionuclides of interest in nuclear medicine and fusion reactor technology or of potential importance in routine or accidental releases from the nuclear fuel cycle. Primary source of the decay data presented in this handbook is the Evaluated Nuclear Structure Data File (ENSDF), developed and maintained by the US Nuclear Data Network. Topics covered include various radioactive decay processes; evaluation process and standards of ENSDF; tables and computer code MEDLIST used to produce ENSDF tables; radiation dosimetry and radiological assessments; parent-daughter activity ratios wherever the adopted decay data may contain significant uncertainties or errors due to the lack of appropriate experimental data

  15. Cosmic background radiation spectral distortion and radiative decays of relic neutral particles

    International Nuclear Information System (INIS)

    Berezhiani, Z.G.; Doroshkevich, A.G.; Khlopov, M.Yu.; Yurov, V.P.; Vysotskij, M.I.

    1989-01-01

    The recently observed excess of photons on a short wavelength side of the peak of a cosmic background radiation spectrum can be described by radiative decays of relic neutral particles. The lifetime and mass of a decaying particle must satisfy the following conditions: 2x10 9 s 14 s, 0.4 eV -9 -8x10 -8 ) μ b , and the interaction of new particles with the usual matter must be rather strong. The generalization of the standard SU(3)xSU(2)xU(1) model is presented which includes new particles with the desired properties. 18 refs.; 3 figs.; 2 tabs

  16. Specification of fast neutron radiation quality from cell transformation data

    International Nuclear Information System (INIS)

    Coppola, M.

    1992-01-01

    Experimental data on the neoplastic transformation of C3H 10T1/2 cells measured at Casaccia after neutron and X-ray irradiation were used to determine neutron RBE values for the RSV-Tapiro fast reactor energy spectrum and for monoenergetic neutrons of 0.5, 1, and 6 MeV. In parallel, micro-dosimetric measurements provided the actual lineal energy distributions and related mean parameters for the reactor radiation. From these experiments, values of the neutron quality factor were derived for the reactor neutron energy spectrum and, in turn, for the other neutron energies tested. A mathematical expression giving a smooth dependence on neutron energy was also determined for the effective quality factor in the entire energy range examined. The results were compared with other proposals

  17. Projected study of neutronic decay of giant resonances and continuum states

    International Nuclear Information System (INIS)

    Blumenfeld, Y.; Chomaz, P.; Fortier, S.; Frascaria, N.; Gales, S.; Guillot, J.; Langevin, H.; Laurent, H.; Maison, J.M.; Nguyen Van Giai

    1988-01-01

    A project to study the decay of very excited states in nuclei is presented. A multidetector to measure these modes for excited structures situated beyond the neutron emission threshold is proposed. Coincidence experiments would allow a study of the wave functions of these elementary excitations and of the damping mechanisms in the nuclear domain. The definition of the characteristics of the system; tests to be carried out before selecting a detector; and nonscientific and nontechnical aspects of the project are also presented [fr

  18. A multiwire proportional chamber for precision studies of neutron β decay angular correlations

    International Nuclear Information System (INIS)

    Ito, T.M.; Carr, R.; Filippone, B.W.; Martin, J.W.; Plaster, B.; Rybka, G.; Yuan, J.

    2007-01-01

    A new multiwire proportional chamber (MWPC) was designed and constructed for precision studies of neutron β decay angular correlations. Its design has several novel features, including the use of low pressure neopentane as the MWPC gas and an entrance window made of thin Mylar sheet reinforced with Kevlar fibers. In the initial off-line performance tests, the gas gain of neopentane and the position resolution were studied

  19. Study of neutron rich nuclei by delayed neutron decay using the Tonnerre multidetector; Etude de la decroissance par neutrons retardes de noyaux legers riches en neutrons avec le multidetecteur tonnerre

    Energy Technology Data Exchange (ETDEWEB)

    Timis, C.N

    2001-07-01

    A new detection array for beta delayed neutrons was built. It includes up to 32 plastic scintillation counters 180 cm long located at 120 cm from the target. Neutron energy spectra are measured by time-of-flight in the 300 keV-15 MeV range with good energy resolution. The device was tested with several known nuclei. Its performances are discussed in comparison with Monte Carlo simulations. They very high overall detection efficiency on the TONNERRE array made it possible to study one and two neutron emission of {sup 11}Li. A complete decay scheme was obtained. The {sup 33}Mg and {sup 35}Al beta decays were investigated for the first time by neutron and gamma spectroscopy. Complete decay schemes were established and compared to large scale shell-model calculations. (authors)

  20. Lageos orbit decay due to infrared radiation from earth

    Science.gov (United States)

    Rubincam, David Parry

    1987-01-01

    Infrared radiation from the earth may be the principal reason for the decay of Lageos' orbit. The radiation heats up the laser retroreflectors embedded in Lageos' aluminum surface. This creates a north-south temperature gradient on the satellite. The gradient in turn causes a force to be exerted on Lageos because of recoil from photons leaving its surface. The delayed heating of the retroreflectors due to their thermal inertia gives the force a net along-track component which always acts like drag. A simple thermal model for the retroreflectors indicates that this thermal drag accounts for about half the observed average along-track acceleration of -3.3 x 10 to the -10th power m/sec squared. The contribution from the aluminum surface to this effect is negligible. The infrared effect cannot explain the large observed fluctuations in drag which occur mainly when the orbit intersects the earth's shadow.

  1. Radiation hygiene aspects of mixed neutron-gamma field dosimetry

    International Nuclear Information System (INIS)

    Nikodemova, O.; Hrabovcova, A.

    1982-01-01

    Various possibilities are analyzed of determining the dose equivalent of neutrons, as is the reliability of the techniques and the correct interpretation for the purposes of radiation hygiene. (author)

  2. Realistic fission models, new beta-decay half-lives and the r-process in neutron star mergers

    International Nuclear Information System (INIS)

    Shibagaki, S.; Kajino, T.; Chiba, S.; Lorusso, G.; Nishimura, S.; Mathews, G. J.

    2014-01-01

    Almost half of heavy nuclei beyond iron are considered to be produced by rapid neutron capture process (r-process). This process occurs in the neutron-rich environment such as core-collapse supernovae or neutron star mergers, but the main production site is still unknown. In the r-process of neutron star mergers, nuclear fission reactions play an important role. Also beta-decay half-lives of magic nuclei are crucial for the r-process. We have carried out r-process nucleosynthesis calculations based upon new theoretical estimates of fission fragment distributions and new beta-decay half-lives for N=82 nuclei measured at RIBF-RIKEN. We investigate the effect of nuclear fission on abundance patterns in the matter ejected from neutron star mergers with two different fission fragment mass distributions. We also discuss how the new experimental beta-decay half-lives affect the r-process

  3. Half-lives of cluster decay of neutron rich nuclei in trans-tin region

    International Nuclear Information System (INIS)

    Swamy, G.S.; Umesh, T.K.

    2011-01-01

    In this work, the logarithmic half-life [log 10 (T 1/2 )] values have been reported for the exotic decay of some neutron rich even–even parent nuclei (56≤Z≤64) accompanied by the emission of alpha-like and non-alpha-like clusters in the trans-tin region. These values were calculated by using the single line of universal curve (UNIV) for alpha and cluster radioactive decay as well as the universal decay law (UDL). The half-life values were also separately calculated by considering the interacting nuclear potential barrier as the sum of Coulomb and proximity potentials. The half-life values based on the three calculations mentioned above, were found to agree with one another within a few orders of magnitude. Possible conclusions are drawn based on the present study. (author)

  4. Measurement of the proton asymmetry (C) in free neutron β-decay with Perkeo III

    Energy Technology Data Exchange (ETDEWEB)

    Raffelt, Lukas Michael

    2016-10-19

    The decay of polarized neutrons can be used to search for Physics Beyond the Standard Model. The non-isotropic angular distributions of the decay particles are parity violating and reveal the true nature of the weak interaction. Many observables are available in the decay of polarized neutrons, but the decay itself is only described by three parameters, which allows searches for new physics in a combined analysis. Measurements of the electron angular correlation coefficient (A) can be used to precisely determine the ratio of the axial to the vector coupling constant. The proton angular correlation coefficient (C) has only been measured once by a predecessor of this experiment. We measured the proton asymmetry with a similar proton detector, but employed a new measuring scheme allowing the collection of the worlds first data on the proton energy dependence of the proton asymmetry. At the current state of the analysis, a statistical uncertainty on the value of C of 0.8 % in each of the two detectors can be reached. For a final value, studies of systematic effects based on field simulations and tracking are still missing. For this measurement I designed and constructed a new detector. For the first time the scintillator was coated with a transparent conductive coating and together with the new CAD milled light-guides in a four-side readout configuration the low energy performance of the detector could be increased. Several systematic effects have been studied, especially the Point Spread Function of the magnetic transport system.

  5. Status of radiation detector and neutron monitor technology

    CERN Document Server

    Kim, Y K; Ha, J H; Han, S H; Hong, S B; Hwang, I K; Lee, W G; Moon, B S; Park, S H; Song, M H

    2002-01-01

    In this report, we describe the current states of the radiation detection technology, detectors for industrial application, and neutron monitors. We also survey the new technologies being applied to this field. The method to detect radiation is the measurement of the observable secondary effect from the interaction between incident radiation and detector material, such as ionization, excitation, fluorescence, and chemical reaction. The radiation detectors can be categorized into gas detectors, scintillation detectors, and semiconductor detectors according to major effects and main applications. This report contains the current status and operational principles of these detectors. The application fields of radiation detectors are industrial measurement system, in-core neutron monitor, medical radiation diagnostic device, nondestructive inspection device, environmental radiation monitoring, cosmic-ray measurement, security system, fundamental science experiment, and radiation measurement standardization. The st...

  6. Application of neutron radiation inspection at the Pantex Plant

    International Nuclear Information System (INIS)

    Cassidy, J.P.

    1983-01-01

    A neutron radiographic capability has been established at the Pantex Plant in Amarillo, Texas, which is operated for the Department of Energy by Mason and Hanger-Silas Mason Co. A 3 MeV Van de Graaf accelerator is employed as the neutron source. Neutron radiation inspection techniques have been developed to detect and observe discontinuities in explosive materials encased in aluminum, lead, steel and combinations of these casement materials. These data demonstrate that the capability exists for obtaining satisfactory neutron radiographs of many explosive-loaded components. Additional work will be performed in order to further determine applicable capabilities of the 3 MeV Van de Graaf accelerator. (Auth.)

  7. Matter and Radiation in Strong Magnetic Fields of Neutron Stars

    International Nuclear Information System (INIS)

    Lai, D

    2006-01-01

    Neutron stars are found to possess magnetic fields ranging from 10 8 G to 10 15 G, much larger than achievable in terrestrial laboratories. Understanding the properties of matter and radiative transfer in strong magnetic fields is essential for the proper interpretation of various observations of magnetic neutron stars, including radio pulsars and magnetars. This paper reviews the atomic/molecular physics and condensed matter physics in strong magnetic fields, as well as recent works on modeling radiation from magnetized neutron star atmospheres/surface layers

  8. Study of two-photon decays of pseudoscalar mesons via J /ψ radiative decays

    Science.gov (United States)

    Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Bai, Y.; Bakina, O.; Baldini Ferroli, R.; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Berger, N.; Bertani, M.; Bettoni, D.; Bian, J. M.; Bianchi, F.; Boger, E.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chai, J.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, P. L.; Chen, S. J.; Chen, X. R.; Chen, Y. B.; Chu, X. K.; Cibinetto, G.; Dai, H. L.; Dai, J. P.; Dbeyssi, A.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; de Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Dou, Z. L.; Du, S. X.; Duan, P. F.; Fang, J.; Fang, S. S.; Fang, Y.; Farinelli, R.; Fava, L.; Fegan, S.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fritsch, M.; Fu, C. D.; Gao, Q.; Gao, X. L.; Gao, Y.; Gao, Y. G.; Gao, Z.; Garzia, I.; Goetzen, K.; Gong, L.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guo, A. Q.; Guo, R. P.; Guo, Y. P.; Haddadi, Z.; Han, S.; Hao, X. Q.; Harris, F. A.; He, K. L.; He, X. Q.; Heinsius, F. H.; Held, T.; Heng, Y. K.; Holtmann, T.; Hou, Z. L.; Hu, H. M.; Hu, T.; Hu, Y.; Huang, G. S.; Huang, J. S.; Huang, X. T.; Huang, X. Z.; Huang, Z. L.; Hussain, T.; Ikegami Andersson, W.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jin, Y.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. L.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Khan, T.; Khoukaz, A.; Kiese, P.; Kliemt, R.; Koch, L.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kuemmel, M.; Kuhlmann, M.; Kupsc, A.; Kühn, W.; Lange, J. S.; Lara, M.; Larin, P.; Lavezzi, L.; Leithoff, H.; Leng, C.; Li, C.; Li, Cheng; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li, H. J.; Li, J. C.; Li, Jin; Li, K. J.; Li, Kang; Li, Ke; Li, Lei; Li, P. L.; Li, P. R.; Li, Q. Y.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Lin, D. X.; Liu, B.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. M.; Liu, Huanhuan; Liu, Huihui; Liu, J. B.; Liu, J. P.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, Ke; Liu, L. D.; Liu, P. L.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqing; Long, Y. F.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, M. M.; Ma, Q. M.; Ma, T.; Ma, X. N.; Ma, X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Malik, Q. A.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Meng, Z. X.; Messchendorp, J. G.; Mezzadri, G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales Morales, C.; Muchnoi, N. Yu.; Muramatsu, H.; Musiol, P.; Mustafa, A.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Papenbrock, M.; Patteri, P.; Pelizaeus, M.; Pellegrino, J.; Peng, H. P.; Peters, K.; Pettersson, J.; Ping, J. L.; Ping, R. G.; Poling, R.; Prasad, V.; Qi, H. R.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, J. J.; Qin, N.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Richter, M.; Ripka, M.; Rong, G.; Rosner, Ch.; Sarantsev, A.; Savrié, M.; Schnier, C.; Schoenning, K.; Shan, W.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Song, J. J.; Song, W. M.; Song, X. Y.; Sosio, S.; Sowa, C.; Spataro, S.; Sun, G. X.; Sun, J. F.; Sun, L.; Sun, S. S.; Sun, X. H.; Sun, Y. J.; Sun, Y. K.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, G. Y.; Tang, X.; Tapan, I.; Tiemens, M.; Tsednee, B.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, D.; Wang, D. Y.; Wang, Dan; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, Meng; Wang, P.; Wang, P. L.; Wang, W. P.; Wang, X. F.; Wang, Y.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. Y.; Wang, Zongyuan; Weber, T.; Wei, D. H.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, L. J.; Wu, Z.; Xia, L.; Xia, Y.; Xiao, D.; Xiao, H.; Xiao, Y. J.; Xiao, Z. J.; Xie, Y. G.; Xie, Y. H.; Xiong, X. A.; Xiu, Q. L.; Xu, G. F.; Xu, J. J.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, L.; Yan, W. B.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang, L.; Yang, Y. H.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yin, J. H.; You, Z. Y.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zeng, Y.; Zeng, Z.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, S. Q.; Zhang, X. Y.; Zhang, Y. H.; Zhang, Y. T.; Zhang, Yang; Zhang, Yao; Zhang, Yu; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhou, Y. X.; Zhu, J.; Zhu, J.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, S. H.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zotti, L.; Zou, B. S.; Zou, J. H.; Besiii Collaboration

    2018-04-01

    Using a sample of 4.48 ×108 ψ (3686 ) events collected with the BESIII detector at the BEPCII collider, we study the two-photon decays of the pseudoscalar mesons π0, η , η', η (1405 ), η (1475 ), η (1760 ), and X (1835 ) in J /ψ radiative decays using ψ (3686 )→π+π-J /ψ events. The π0, η , and η' mesons are clearly observed in the two-photon mass spectra, and the branching fractions are determined to be B (J /ψ →γ π0→3 γ )=(3.57 ±0.12 ±0.16 )×10-5 , B (J /ψ →γ η →3 γ )=(4.42 ±0.04 ±0.18 )×10-4 , and B (J /ψ →γ η'→3 γ )=(1.26 ±0.02 ±0.05 )×10-4 , where the first error is statistical and the second is systematic. No clear signal for η (1405 ), η (1475 ), η (1760 ) or X (1835 ) is observed in the two-photon mass spectra, and upper limits at the 90% confidence level on the product branching fractions are obtained.

  9. Position sensitive detection of neutrons in high radiation background field.

    Science.gov (United States)

    Vavrik, D; Jakubek, J; Pospisil, S; Vacik, J

    2014-01-01

    We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e(-) radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm(2)) spectroscopic Timepix detector adapted for neutron detection utilizing very thin (10)B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10(-4).

  10. Cosmic radiation dose in aircraft - a neutron track etch detector

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, B.; Radolic, V.; Miklavcic, I.; Poje, M.; Varga, M. [Department of Physics, University of Osijek, 31000 Osijek, P.O. Box 125, Gajev trg 6 (Croatia); Planinic, J. [Department of Physics, University of Osijek, 31000 Osijek, P.O. Box 125, Gajev trg 6 (Croatia)], E-mail: planinic@ffos.hr

    2007-12-15

    Cosmic radiation bombards us at high altitude by ionizing particles. The radiation environment is a complex mixture of charged particles of solar and galactic origin, as well as of secondary particles produced in interaction of the galactic cosmic particles with the nuclei of atmosphere of the Earth. The radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard ATR 42 and A 320 aircrafts (flight level of 8 and 11 km, respectively) was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter. The estimated occupational effective dose for the aircraft crew (A 320) working 500 h per year was 1.64 mSv. Other experiments, or dose rate measurements with the neutron dosimeter, consisting of LR-115 track detector and boron foil BN-1 or 10B converter, were performed on five intercontinental flights. Comparison of the dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level showed that the neutron component carried about 50% of the total dose. The dose rate measurements on the flights from the Middle Europe to the South and Middle America, then to Korea and Japan, showed that the flights over or near the equator region carried less dose rate; this was in accordance with the known geomagnetic latitude effect.

  11. Cosmic radiation dose in aircraft - a neutron track etch detector

    International Nuclear Information System (INIS)

    Vukovic, B.; Radolic, V.; Miklavcic, I.; Poje, M.; Varga, M.; Planinic, J.

    2007-01-01

    Cosmic radiation bombards us at high altitude by ionizing particles. The radiation environment is a complex mixture of charged particles of solar and galactic origin, as well as of secondary particles produced in interaction of the galactic cosmic particles with the nuclei of atmosphere of the Earth. The radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard ATR 42 and A 320 aircrafts (flight level of 8 and 11 km, respectively) was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter. The estimated occupational effective dose for the aircraft crew (A 320) working 500 h per year was 1.64 mSv. Other experiments, or dose rate measurements with the neutron dosimeter, consisting of LR-115 track detector and boron foil BN-1 or 10B converter, were performed on five intercontinental flights. Comparison of the dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level showed that the neutron component carried about 50% of the total dose. The dose rate measurements on the flights from the Middle Europe to the South and Middle America, then to Korea and Japan, showed that the flights over or near the equator region carried less dose rate; this was in accordance with the known geomagnetic latitude effect

  12. Nuclear-decay studies of neutron-rich rare-earth nuclides

    International Nuclear Information System (INIS)

    Chasteler, R.M.

    1990-01-01

    Neutron-rich rare-earth nuclei were produced in multinucleon transfer reactions of 170 Er and 176 Yb projectiles on nat W targets at the Lawrence Berkeley Laboratory SuperHILAC and their radioactive decays properties studied at the on-line mass separation facility OASIS. Two unknown isotopes, 169 Dy (t 1/2 = 39 ± 8 s) and 174 Er(t 1/2 = 3.3 ± 0.2 m) were discovered and their decay characteristics determined. The decay schemes for two previously identified isotopes, 168 Dy (t 1/2 = 8.8 ± 0.3 m) and 171 Ho (t 1/2 = 55 ± 3 s), were characterized. Evidence for a new isomer of 3.0 m 168 Ho g , 168 Ho m (t 1/2 = 132 ± 4 s) which decays by isomeric transition (IT) is presented. Beta particle endpoint energies were determined for the decay of 168 Ho g , 169 Dy, 171 Ho, and 174 Er, the resulting Qβ-values are: 2.93 ± 0.03, 3.2 ± 0.3, 3.2 ± 0.6, and 1.8 ± 0.2 MeV, respectively. These values were compared with values calculated using recent atomic mass formulae. Comparisons of various target/ion source geometries used in the OASIS mass separator facility for these multinucleon transfer reactions were performed. 73 refs., 40 figs., 11 tabs

  13. Studies of radiative B meson decays with Bells

    International Nuclear Information System (INIS)

    Nakao, Mikihiko

    2001-01-01

    We have studied radiative B meson decays using a 5.1 fb -1 data sample collected at the Γ(4S) resonance with the Belle detector at the KEKB e + e - collider. The inclusive branching fraction Β(b→sγ)=(3.34±0.50 -0.37-0.28 +0.34+0.26 )x10 -4 is measured using a technique to subtract the background contribution that requires a relatively small amount of off-resonance data. We measure the exclusive branching fractions to the K * γ final states to be Β(B 0 →K * (892) 0 γ)=(4.94±0.93 -0.52 +0.55 )x10 -5 and Β(B + →K * (892) + γ)=(2.87±1.20 -0.40 +0.55 )x10 -5 . We searched for B→ργ decays and obtained an upper limit of Β(B→ργ)/Β(B→K * γ) * γ to a negligible level. (author)

  14. Photon energy scale determination and commissioning with radiative Z decays

    CERN Document Server

    Bondu, Olivier

    2012-01-01

    The CMS electromagnetic calorimeter (ECAL) is composed of 75848 lead-tungstate scintillating crystals. It has been designed to be fast, compact, and radiation-hard, with fine granularity and excellent energy resolution. Obtaining the design resolution is a crucial challenge for the SM Higgs search in the two photon channel at the LHC, and more generally good photon calibration and knowledge of the photon energy scale is required for analyses with photons in the final state. The behavior of photons and electrons in the calorimeter is not identical, making the use of a dedicated standard candle for photons, complementary to the canonical high-yield $Z^0$ decay to electrons, highly desirable. The use of $Z^0$ decays to a pair of muons, where one of the muons emits a Bremstrahlung photon, can be such a standard candle. These events, which can be cleanly selected, are a source of high-purity, relatively high-pt photons. Their kinematics are well-constrained by the $Z^0$ boson mass and the precision on the muon ...

  15. Radiative decays of the upsilon (2S) resonance

    International Nuclear Information System (INIS)

    Irion, J.

    1984-04-01

    The Crystal Ball Detector at DORIS II was used to study radiative decays of the upsilon (2S) resonance with more than twice the previously available data. The inclusive photon spectrum of hadronic upsilon (2S) decays and the exclusive channel upsilon (2S) → γγ upsilon (1S) → γγ l + l - were analyzed. In the inclusive spectrum three significant photon lines at energies of Eγ 1 = (108.2 +- 0.7 +- 4) MeV, Eγ 1 = (127.1 +- 0.8 +- 4) MeV and Eγ 3 = (160.0 +- 2.4 +- 4) MeV with branching fractions of (6.0 +- 0.7 +- 0.9)%, (6.6 +- 0.8 +- 1.0)%, (2.6 +- 0.7 +- 0.8)% respectively were measured. The lines are consistent with being transitions from the upsilon (2S) to the 3 P 2 , 3 P 1 and 3 P 0 states. In addition a line at Eγ approx. 427 MeV was observed which is interpreted as transitions from the 3 P 2 1 states to the upsilon (1S). 17 references

  16. Radiation damage in molybdenum and tungsten in high neutron fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Veljkovic, S; Milasin, N [Institute of Nuclear Sciences Boris Kidric, Department of Reactor Materials, Vinca, Beograd (Serbia and Montenegro)

    1964-04-15

    The effects of radiation on molybdenum and tungsten in high neutron fluxes are presented. The changes induced, particularly defects with a high migration activation energy, are analyzed. The correlation of these changes with the basic concepts of radiation damage in solids is considered. An attempt is made to relate the defects studied with the changes in macroscopic properties (author)

  17. Radiation damage in molybdenum and tungsten in high neutron fluxes

    International Nuclear Information System (INIS)

    Veljkovic, S.; Milasin, N.

    1964-01-01

    The effects of radiation on molybdenum and tungsten in high neutron fluxes are presented. The changes induced, particularly defects with a high migration activation energy, are analyzed. The correlation of these changes with the basic concepts of radiation damage in solids is considered. An attempt is made to relate the defects studied with the changes in macroscopic properties (author)

  18. Commissioning of the IDS Neutron Detector and $\\beta$-decay fast-timing studies at IDS

    CERN Document Server

    Piersa, Monika

    2016-01-01

    The following report describes my scientific activities performed during the Summer Student Programme at ISOLDE. The main part of my project was focused on commissioning the neutron detector dedicated to nuclear decay studies at ISOLDE Decay Station (IDS). I have participated in all the steps needed to make it operational for the IS609 experiment. In the testing phase, we obtained expected detector response and calibrations confirmed its successful commissioning. The detector was mounted in the desired geometry at IDS and used in measurements of the beta-delayed neutron emission of $^8$He. After completing aforementioned part of my project, I became familiar with the fast-timing method. This technique was applied at IDS in the IS610 experiment performed in June 2016 to explore the structure of neutron-rich $^{130-134}$Sn nuclei. Since the main part of my PhD studies will be the analysis of data collected in this experiment, the second part of my project was dedicated to acquiring knowledge about technical de...

  19. Prompt Neutron Decay Constant Determination Of Silicide Transition Core Using Noise Method

    International Nuclear Information System (INIS)

    Jujuratisbela, Uju; Yulianto, Yusi Eko; Cahyana

    2001-01-01

    Chairman of BATAN had decided to replace the Oxide fuel element type of RSG-GAS into silicide element type step by step. The replacement will create core transitions. Kinetic characteristic of the transition cores have to be monitored in order to know the deviation of core behavior. For that reason, the kinetic parameters have to be measured. Prompt neutron decay constant (alpha) is one of the kinetic parameters that has to be monitored continuously in the transition cores. In order not to disturb the normal operation of reactor, alpha parameter should be measured by using noise analysis method. The voltage of neutron flux at power of 15 MW is connected to preamplifier and filter then to the Dynamic Signal Analyzer Version-2 and then the auto power spectral density (APSD) was determined by using Fast Fourier transform. From the APSD curve of each channel of JKT03, the cut off frequency of each channel can be determined by using linear regression technique such that the prompt neutron decay constant can be estimated

  20. Analysis of the WCLL European demo blanket concept in terms of activation and decay heat after exposure to neutron irradiation

    Directory of Open Access Journals (Sweden)

    Stankunas Gediminas

    2017-01-01

    Full Text Available This comparative paper describes the activation and decay heat calculations for water-cooled lithium-lead performed part of the EURO fusion WPSAE programme and specifications in comparison to other European DEMO blanket concepts on the basis of using a three-dimensional neutronics calculation model. Results are provided for a range of decay times of interest for maintenance activities, safety and waste management assessments. The study revealed that water-cooled lithium-lead has the highest total decay heat at longer decay times in comparison to the helium-cooled design which has the lowest total decay heat. In addition, major nuclides were identified for water-cooled lithium-lead in W armour, Eurofer, and LiPb. In addition, great attention has been dedicated to the analysis of the decay heat and activity both from the different water-cooled lithium-lead blanket modules for the entire reactor and from each water-cooled lithium-lead blanket module separately. The neutron induced activation and decay heat at shutdown were calculated by the FISPACT code, using the neutron flux densities and spectra that were provided by the preceding MCNP neutron transport calculations.

  1. Radiobiological basis for setting neutron radiation safety standards

    International Nuclear Information System (INIS)

    Straume, T.

    1985-01-01

    Present neutron standards, adopted more than 20 yr ago from a weak radiobiological data base, have been in doubt for a number of years and are currently under challenge. Moreover, recent dosimetric re-evaluations indicate that Hiroshima neutron doses may have been much lower than previously thought, suggesting that direct data for neutron-induced cancer in humans may in fact not be available. These recent developments make it urgent to determine the extent to which neutron cancer risk in man can be estimated from data that are available. Two approaches are proposed here that are anchored in particularly robust epidemiological and experimental data and appear most likely to provide reliable estimates of neutron cancer risk in man. The first approach uses gamma-ray dose-response relationships for human carcinogenesis, available from Nagasaki (Hiroshima data are also considered), together with highly characterized neutron and gamma-ray data for human cytogenetics. When tested against relevant experimental data, this approach either adequately predicts or somewhat overestimates neutron tumorigenesis (and mutagenesis) in animals. The second approach also uses the Nagasaki gamma-ray cancer data, but together with neutron RBEs from animal tumorigenesis studies. Both approaches give similar results and provide a basis for setting neutron radiation safety standards. They appear to be an improvement over previous approaches, including those that rely on highly uncertain maximum neutron RBEs and unnecessary extrapolations of gamma-ray data to very low doses. Results suggest that, at the presently accepted neutron dose limit of 0.5 rad/yr, the cancer mortality risk to radiation workers is not very different from accidental mortality risks to workers in various nonradiation occupations

  2. Radiative corrections to the background of μ → e γ decay

    International Nuclear Information System (INIS)

    Arbuzov, A.B.; Kuraev, Eh.A.; Magar, E.; Shajkhatdenov, B.G.; Krehl, O.

    1998-01-01

    Radiative muon decay in the kinematics similar to the neutrinoless decay μ → e γ is considered. Radiative corrections due to one-loop virtual photons and emission of additional soft or hard photons are taken into account. Analytical expressions and numerical estimations are presented

  3. The use of diffusion theory to compute invasion effects for the pulsed neutron thermal decay time log

    International Nuclear Information System (INIS)

    Tittle, C.W.

    1992-01-01

    Diffusion theory has been successfully used to model the effect of fluid invasion into the formation for neutron porosity logs and for the gamma-gamma density log. The purpose of this paper is to present results of computations using a five-group time-dependent diffusion code on invasion effects for the pulsed neutron thermal decay time log. Previous invasion studies by the author involved the use of a three-dimensional three-group steady-state diffusion theory to model the dual-detector thermal neutron porosity log and the gamma-gamma density log. The five-group time-dependent code MGNDE (Multi-Group Neutron Diffusion Equation) used in this work was written by Ferguson. It has been successfully used to compute the intrinsic formation life-time correction for pulsed neutron thermal decay time logs. This application involves the effect of fluid invasion into the formation

  4. Study of the background neutron and gamma components of the ββ(0ν) decay in the NEMO2 prototype detector. Consequences for the NEMO3 detector

    International Nuclear Information System (INIS)

    Marquet, Christine

    1999-01-01

    Neutrinoless double beta decay ββ(0ν) is a test of physics beyond the Standard Model by involving the existence of a massive Majorana neutrino (ν = ν-bar). To try to observe such a process with a sensitivity of 0.1 eV on the neutrino effective mass ( ν >), NEMO collaboration build the NEMO3 detector, able to measure half-lives greater than 10 24 years, corresponding to a few detected events per year. For that, it is necessary to know and master all background sources. This work was first dedicated to the study of external (to the double beta source) background with crossing electrons recorded with NEMO2 prototype detector and then to the simulation of this background in NEMO3 detector. Comparison between NEMO2 data and results of gamma and neutron simulations for different shieldings, with and without neutron source, has allowed to determine background contributions of radon, thoron, 208 Tl contaminations in materials, photon flux produced in laboratory and neutrons. This study, which has required improvements in the MICAP neutron simulation code by developing a photon generator, proved that radiative capture of fast neutrons thermalized in the detector was the source of events in the energy domain of the ββ(0ν) signal. In order to reach the required sensitivity on ν > mass, it has been shown that both a neutron shielding and magnetic field are necessary for NEMO3 detector. (author) [fr

  5. Disordered nuclear pasta, magnetic field decay, and crust cooling in neutron stars

    Science.gov (United States)

    Horowitz, C. J.; Berry, D. K.; Briggs, C. M.; Caplan, M. E.; Cumming, A.; Schneider, A. S.

    2015-04-01

    Nuclear pasta, with non-spherical shapes, is expected near the base of the crust in neutron stars. Large scale molecular dynamics simulations of pasta show long lived topological defects that could increase electron scattering and reduce both the thermal and electrical conductivities. We model a possible low conductivity pasta layer by increasing an impurity parameter Qimp. Predictions of light curves for the low mass X-ray binary MXB 1659-29, assuming a large Qimp, find continued late time cooling that is consistent with Chandra observations. The electrical and thermal conductivities are likely related. Therefore observations of late time crust cooling can provide insight on the electrical conductivity and the possible decay of neutron star magnetic fields (assuming these are supported by currents in the crust). This research was supported in part by DOE Grants DE-FG02-87ER40365 (Indiana University) and DE-SC0008808 (NUCLEI SciDAC Collaboration).

  6. Measurement of the transverse polarization of electrons emitted in free-neutron decay.

    Science.gov (United States)

    Kozela, A; Ban, G; Białek, A; Bodek, K; Gorel, P; Kirch, K; Kistryn, St; Kuźniak, M; Naviliat-Cuncic, O; Pulut, J; Severijns, N; Stephan, E; Zejma, J

    2009-05-01

    Both components of the transverse polarization of electrons (sigmaT1, sigmaT2) emitted in the beta-decay of polarized, free neutrons have been measured. The T-odd, P-odd correlation coefficient quantifying sigmaT2, perpendicular to the neutron polarization and electron momentum, was found to be R=0.008+/-0.015+/-0.005. This value is consistent with time reversal invariance and significantly improves limits on the relative strength of imaginary scalar couplings in the weak interaction. The value obtained for the correlation coefficient associated with sigmaT1, N=0.056+/-0.011+/-0.005, agrees with the Standard Model expectation, providing an important sensitivity test of the experimental setup.

  7. Bound-state β decay of a neutron in a strong magnetic field

    International Nuclear Information System (INIS)

    Kouzakov, Konstantin A.; Studenikin, Alexander I.

    2005-01-01

    The β decay of a neutron into a bound (pe - ) state and an antineutrino in the presence of a strong uniform magnetic field (B > or approx. 10 13 G) is considered. The β decay process is treated within the framework of the standard model of weak interactions. A Bethe-Salpeter formalism is employed for description of the bound (pe - ) system in a strong magnetic field. For the field strengths 10 13 18 G the estimate for the ratio of the bound-state decay rate w b and the usual (continuum-state) decay rate w c is derived. It is found that in such strong magnetic fields w b /w c ∼0.1-0.4. This is in contrast to the field-free case, where w b /w c ≅4.2x10 -6 [J. N. Bahcall, Phys. Rev. 124, 495 (1961); L. L. Nemenov, Sov. J. Nucl. Phys. 15, 582 (1972); X. Song, J. Phys. G: Nucl. Phys. 13, 1023 (1987)]. The dependence of the ratio w b /w c on the magnetic field strength B exhibits a logarithmiclike behavior. The obtained results can be important for applications in astrophysics and cosmology

  8. Search for Time Reversal Violation in Neutron Decay: A Measurement of the Transverse Polarization of Electrons

    International Nuclear Information System (INIS)

    Bodek, K.; Kaczmarek, A.; Kistryn, St.; Kuzniak, M.; Zejma, J.; Pulut, J.; Kirch, K.; Bialek, A.; Kozela, A.; Ban, G.; Naviliat-Cuncic, O.; Gorel, P.; Beck, M.; Lindroth, A.; Severijns, N.; Stephan, E.; Czarnecki, A.

    2006-01-01

    A non-zero value of the R-correlation coefficient due to the e - polarization component, perpendicular to the plane spanned by the spin of the decaying neutron and the electron momentum, would signal a violation of time reversal symmetry and thus physics beyond the Standard Model. The value of the N-correlation coefficient, given by the transverse e - polarization component within that plane, is expected to be finite. The measurement of N serves as an important systematic check of the apparatus for the R-measurement. The first phase of data taking has been completed. Preliminary results from a limited data sample show no deviations from the Standard Model predictions

  9. β Decay processes of neutron-rich isotopes of sodium and magnesium

    International Nuclear Information System (INIS)

    Guillemaud, D.

    1982-01-01

    The γ and n activities from the β decay of Na isotopes up to 34 Na, which are formed in high-energy fragmentation and analysed through mass-spectrometry techniques, are observed as well as those from their Mg descendants. Their intensities Isub(γ) and Isub(β) are measured; some radioactive half lives are determined. Delayed-neutron branching ratios Pn are measured. The existence of 35 Na is for the first time indicated. The position of the first excited 2 + level is taken as an indication of a stronger deformation for that isotope [fr

  10. Characterization of the radiation background at the Spallation Neutron Source

    International Nuclear Information System (INIS)

    DiJulio, Douglas D.; Cherkashyna, Nataliia; Scherzinger, Julius; Khaplanov, Anton; Pfeiffer, Dorothea; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Kanaki, Kalliopi; Kirstein, Oliver; Hall-Wilton, Richard J.; Bentley, Phillip M.; Ehlers, Georg; Gallmeier, Franz X.; Hornbach, Donald E.; Iverson, Erik B.; Newby, Robert J.

    2016-01-01

    We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis 4 He detector, and a standard NaI photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden. (paper)

  11. Nuclear spectroscopy of neutron rich A = 147 nuclides: decay of 147Cs, 147Ba and 147La

    International Nuclear Information System (INIS)

    Shmid, M.; Chu, Y.Y.; Gowdy, G.M.

    1981-01-01

    A study of the beta decay of neutron rich nuclides of the A = 147 chain was carried out at the TRISTAN isotope separator. Half lives of 14 'Cs, 147 Ba and 147 La were measured. Six gamma lines are assigned to 147 Cs decay. A decay scheme for 147 Ba with levels up to 2 MeV is proposed for the first time. A partial decay scheme for 147 La is proposed, which confirms the previously existing one, with five new levels added from the present work

  12. Present status of the radiative neutron capture mechanisms -nonstatistical effects

    International Nuclear Information System (INIS)

    Brzosko, J.S.

    1976-01-01

    The present status of our knowledge about neutron radiative capture mechanisms is described. In the first section there are given a review on mathematical description of the neutron capture cross section and possible sources of correlation effects. The point of lecture is the explanation of connections between the intermediate structures and correlation effects. In one of the sections the explanation of the bump in γ-ray spectra is discussed. The typical experimental results are presented. (author)

  13. Partial radiative capture of resonance neutrons; Capture radiative partielle des neutrons de resonance

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    The radiative capture of resonance neutrons has been studied near the Saclay linac between 0.5 and 700 eV with time-of-flight method and a Ge(Li) detector. {sup 195}Pt + n and {sup 183}W + n allow the study of the distribution of partial radiative widths and their eventual correlation and also the variation of < {gamma}{sub {gamma}{sub i}} > with E{sub {gamma}}. The mean values of Ml and El transition intensities are compared in several tin isotopes. Interference effects, either between resonances or between direct capture and resonant capture are found in {sup 195}Pt + n, {sup 197}Au + n and {sup 59}Co + n. The excited level schemes of a great deal of nuclei are obtained and compared with theoretical predictions. This study has been completed by an analysis of thermal spectrum. (author) [French] La capture radiative des neutrons de resonance a ete etudiee pres de l'accelerateur lineaire de Saclay entre 0,5 et 700 eV a l'aide de la methode du temps-de-vol et d'un detecteur Ge(Li). Les noyaux {sup 195}Pt + n et {sup 183}W + n permettent l'analyse de la distribution de resonance en resonance des largeurs radiatives partielles {gamma}{sub {gamma}{sub i}} et de leur eventuelle correlation, ainsi que l'etude de la variation de < {gamma}{sub {gamma}{sub i}} > en fonction de E{sub {gamma}}. Les intensites moyennes des transitions Ml et El sont comparees pour quelques isotopes de l'etain. Des effets d'interference, soit entre resonances, soit entre capture directe et capture resonnante sont mis en evidence dans {sup 195}Pt + n, {sup 197}Au + n et {sup 59}Co + n. Enfin les schemas des etats excites d'un grand nombre de noyaux sont obtenus et compares avec les predictions theoriques. Cette etude a ete completee par une analyse des spectres thermiques. (auteur)

  14. Partial radiative capture of resonance neutrons; Capture radiative partielle des neutrons de resonance

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    The radiative capture of resonance neutrons has been studied near the Saclay linac between 0.5 and 700 eV with time-of-flight method and a Ge(Li) detector. {sup 195}Pt + n and {sup 183}W + n allow the study of the distribution of partial radiative widths and their eventual correlation and also the variation of < {gamma}{sub {gamma}{sub i}} > with E{sub {gamma}}. The mean values of Ml and El transition intensities are compared in several tin isotopes. Interference effects, either between resonances or between direct capture and resonant capture are found in {sup 195}Pt + n, {sup 197}Au + n and {sup 59}Co + n. The excited level schemes of a great deal of nuclei are obtained and compared with theoretical predictions. This study has been completed by an analysis of thermal spectrum. (author) [French] La capture radiative des neutrons de resonance a ete etudiee pres de l'accelerateur lineaire de Saclay entre 0,5 et 700 eV a l'aide de la methode du temps-de-vol et d'un detecteur Ge(Li). Les noyaux {sup 195}Pt + n et {sup 183}W + n permettent l'analyse de la distribution de resonance en resonance des largeurs radiatives partielles {gamma}{sub {gamma}{sub i}} et de leur eventuelle correlation, ainsi que l'etude de la variation de < {gamma}{sub {gamma}{sub i}} > en fonction de E{sub {gamma}}. Les intensites moyennes des transitions Ml et El sont comparees pour quelques isotopes de l'etain. Des effets d'interference, soit entre resonances, soit entre capture directe et capture resonnante sont mis en evidence dans {sup 195}Pt + n, {sup 197}Au + n et {sup 59}Co + n. Enfin les schemas des etats excites d'un grand nombre de noyaux sont obtenus et compares avec les predictions theoriques. Cette etude a ete completee par une analyse des spectres thermiques. (auteur)

  15. Introduction of neutron metrology for reactor radiation damage

    International Nuclear Information System (INIS)

    Alberman, A.; Genthon, J.P.; Schneider, W.; Wright, S.B.; Zijp, W.L.

    1979-01-01

    The background of the procedures for determining irradiation parameters which are of interest in radiation damage experiments is described. The first two chapters outline the concept of damage functions and damage models. The next two chapters give information on methods to determine neutron fluences and neutron spectra. The fifth chapter gives a review of correlation data available for graphite and steels. The last chapter gives guidance how to report the relevant irradiation parameters. Attention is given to the role of the neutron spectrum in deriving values for damage fluence, energy transferred to the lattice, and number of displacements

  16. Variation of Neutron Moderating Power on HDPE by Gamma Radiation

    International Nuclear Information System (INIS)

    Park, Kwang June; Ju, June Sik; Kang, Hee Young; Shin, Hee Sung; Kim, Ho Dong

    2009-01-01

    High density polyethylene (HDPE) is degraded due to a radiation-induced oxidation when it is used as a neutron moderator in a neutron counter for a nuclear material accounting of spent fuels. The HDPE exposed to the gamma-ray emitted from the fission products in a spent nuclear fuel results in a radiation-induced degradation which changes its original molecular structure to others. So a neutron moderating power variation of HDPE, irradiated by a gamma radiation, was investigated in this work. Five HDPE moderator structures were exposed to the gamma radiation emitted from a 60 Co source to a level of 10 5 -10 9 rad to compare their post-irradiation properties. As a result of the neutron measurement test with 5 irradiated HDPE structures and a neutron measuring system, it was confirmed that the neutron moderating power for the 105 rad irradiated HDPE moderator revealed the largest decrease when the un-irradiated pure one was used as a reference. It implies that a neutron moderating power variation of HDPE is not directly proportional to the integrated gamma dose rate. To clarify the cause of these changes, some techniques such as a FTIR, an element analysis and a densitometry were employed. As a result of these analyses, it was confirmed that the molecular structure of the gamma irradiated HDPEs had partially changed to others, and the contents of hydrogen and oxygen had varied during the process of a radiation-induced degradation. The mechanism of these changes cannot be explained in detail at present, and thus need further study

  17. Development of ITER diagnostics: Neutronic analysis and radiation hardness

    Energy Technology Data Exchange (ETDEWEB)

    Vukolov, Konstantin, E-mail: vukolov_KY@nrcki.ru; Borisov, Andrey; Deryabina, Natalya; Orlovskiy, Ilya

    2015-10-15

    Highlights: • Problems of ITER diagnostics caused by neutron radiation from hot DT plasma considered. • Careful neutronic analysis is necessary for ITER diagnostics development. • Effective nuclear shielding for ITER diagnostics in the 11th equatorial port plug proposed. • Requirements for study of radiation hardness of diagnostic elements defined. • Results of optical glasses irradiation tests in a fission reactor given. - Abstract: The paper is dedicated to the problems of ITER diagnostics caused by effects of radiation from hot DT plasma. An effective nuclear shielding must be arranged in diagnostic port plugs to meet the nuclear safety requirements and to provide reliable operation of the diagnostics. This task can be solved with the help of neutronic analysis of the diagnostics environment within the port plugs at the design stage. Problems of neutronic calculations are demonstrated for the 11th equatorial port plug. The numerical simulation includes the calculations of neutron fluxes in the port-plug and in the interspace. Options for nuclear shielding, such as tungsten collimator, boron carbide and water moderators, stainless steel and lead screens are considered. Data on neutron fluxes along diagnostic labyrinths allow to define radiation hardness requirements for the diagnostic components and to specify their materials. Options for windows and lenses materials for optical diagnostics are described. The results of irradiation of flint and silica glasses in nuclear reactor have shown that silica KU-1 and KS-4V retain transparency in visible range after neutron fluence of 10{sup 17} cm{sup −2}. Flints required for achromatic objectives have much less radiation hardness about 5 × 10{sup 14} n/cm{sup 2}.

  18. Investigation of radiation damage effects in neutron irradiated CCD

    International Nuclear Information System (INIS)

    Brau, James E.; Igonkina, Olga; Potter, Chris T.; Sinev, Nikolai B.

    2005-01-01

    A Charge Coupled Devices (CCD)-based vertex detector is a leading option for vertex detection at the future linear collider. A major issue for this application is the radiation hardness of such devices. Tests of radiation hardness of CCDs used in the SLD vertex detector, VXD3, have been reported earlier. The first measurements of 1998 involved a spare VXD3 CCD that was irradiated with neutrons from a radioactive source (Pu-Be), and from a nuclear reactor. In 2003, we had the opportunity to disassemble the VXD3 detector and study the nature of the radiation damage it incurred during 3 years of operation at SLC. In the preparation for this study, additional experiments with the spare VXD3 CCD were performed. These included measurements of trapping times in neutron irradiated CCDs. Results, reported here, will help us better understand the mechanism of radiation damage effects and develop techniques to minimize performance degradation due to radiation damage

  19. Radiation Hardness tests with neutron flux on different Silicon photomultiplier devices

    Science.gov (United States)

    Cattaneo, P. W.; Cervi, T.; Menegolli, A.; Oddone, M.; Prata, M.; Prata, M. C.; Rossella, M.

    2017-07-01

    Radiation hardness is an important requirement for solid state readout devices operating in high radiation environments common in particle physics experiments. The MEG II experiment, at PSI, Switzerland, investigates the forbidden decay μ+ → e+ γ. Exploiting the most intense muon beam of the world. A significant flux of non-thermal neutrons (kinetic energy Ek>= 0.5 MeV) is present in the experimental hall produced along the beam-line and in the hall itself. We present the effects of neutron fluxes comparable to the MEG II expected doses on several Silicon Photomultiplier (SiPMs). The tested models are: AdvanSiD ASD-NUV3S-P50 (used in MEG II experiment), AdvanSiD ASD-NUV3S-P40, AdvanSiD ASD-RGB3S-P40, Hamamatsu and Excelitas C30742-33-050-X. The neutron source is the thermal Sub-critical Multiplication complex (SM1) moderated with water, located at the University of Pavia (Italy). We report the change of SiPMs most important electric parameters: dark current, dark pulse frequency, gain, direct bias resistance, as a function of the integrated neutron fluency.

  20. Isotonic and isotopic dependence of the radiative neutron capture cross-section on the neutron excess

    International Nuclear Information System (INIS)

    Trofimov, Yu.N.

    1991-01-01

    The radiative neutron capture cross-section of nuclei has been derived as a function of neutron excess on the basis of the exponential dependence of the cross-section on the reaction energy. It is shown that unknown cross-sections of stable and radioactive nuclei may be evaluated by using the isotonic and isotopic dependence together with available reference cross-section measurements. (author). 4 refs, 3 figs

  1. Importance of the neutron spectrum for determination of radiation damage

    International Nuclear Information System (INIS)

    Hehn, G.; Stiller, P.; Mattes, M.

    1977-01-01

    Since the radiation effects of neutrons depend strongly on the neutron energy, the correlation between the induced damage and the fluence of the fast neutrons shows appreciable disadvantages. The measured values of changes in material properties resulted in large differences for the same fast neutron fluence, being partly due to different neutron spectra. The uncertainties in damage data led to strong overdesign of important structural components. Different neutron environment at surveillance sample position may give an underestimation of the embrittlement in the reactor pressure vessel, which has to be avoided. The application of damage functions combined with accurately calculated neutron spectra, promise to be a reasonable solution. The damage function has the advantage of a phenomenological quantity that all spectral effects are included. But the correlation quantity has to be determined of high experimental costs. Therefore approximations of its energy distributions are very important. For the keV energy region the kerma function is reasonably good. For the MeV energy region a higher effort is needed to calculate the displacement cross section. The same holds for the low energy part. In all three parts the formation of stable material property levels may vary, so that the final correlation can be determined only by measurements of material properties in different neutron spectra. In material samples the spectra distribution of the displacement production rate was determined at different local positions outside the reactor core of a PWR and a fast breeder showing the most important energy regions of both reactors. (orig.) [de

  2. Measurement of radiation skyshine with D-T neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, S.; Nishitani, T. E-mail: nisitani@naka.jaeri.go.jp; Ochiai, K.; Kaneko, J.; Hori, J.; Sato, S.; Yamauchi, M.; Tanaka, R.; Nakao, M.; Wada, M.; Wakisaka, M.; Murata, I.; Kutsukake, C.; Tanaka, S.; Sawamura, T.; Takahashi, A

    2003-09-01

    The D-T neutron skyshine experiments have been carried out at the Fusion Neutronics Source (FNS) of JAERI with the neutron yield of {approx}1.7x10{sup 11} n/s. The concrete thickness of the roof and the wall of a FNS target room are 1.15 and 2 m, respectively. The FNS skyshine port with a size of 0.9x0.9 m{sup 2} was open during the experimental period. The radiation dose rate outside the target room was measured a maximum distance of 550 m from the D-T target point with a spherical rem-counter. Secondary gamma-rays were measured with high purity Ge detectors and NaI scintillation counters. The highest neutron dose was about 9x10{sup -22} Sv/(source neutron) at a distance of 30 m from the D-T target point and the dose rate was attenuated to 4x10{sup -24} Sv/(source neutron) at a distance of 550 m. The measured neutron dose distribution was analyzed with Monte Carlo code MCNP-4B and a simple line source model. The MCNP calculation overestimates the neutron dose in the distance range larger than 230 m. The line source model agrees well with the experimental results within the distance of 350 m.

  3. Neutron radiative capture methods for surface elemental analysis

    Science.gov (United States)

    Trombka, J.I.; Senftle, F.; Schmadebeck, R.

    1970-01-01

    Both an accelerator and a 252Cf neutron source have been used to induce characteristic gamma radiation from extended soil samples. To demonstrate the method, measurements of the neutron-induced radiative capture and activation gamma rays have been made with both Ge(Li) and NaI(Tl) detectors, Because of the possible application to space flight geochemical analysis, it is believed that NaI(Tl) detectors must be used. Analytical procedures have been developed to obtain both qualitative and semiquantitative results from an interpretation of the measured NaI(Tl) pulse-height spectrum. Experiment results and the analytic procedure are presented. ?? 1970.

  4. Decay spectroscopy of neutron-rich nuclei with the CAITEN detector

    Energy Technology Data Exchange (ETDEWEB)

    Steiger, Konrad [Physik-Department E12, Technische Universitaet Muenchen (Germany); Collaboration: CAITEN-Collaboration

    2012-07-01

    An experiment in fall 2010 at the RIBF (Radioactive Ion Beam Factory at RIKEN, Japan) investigated the neutron-rich nuclei in the neighborhood of {sup 30}Ne and {sup 36}Mg. These nuclei were produced by relativistic projectile fragmentation of a 345 AMeV {sup 48}Ca primary beam which was delivered from the superconducting ring cyclotron SRC with an average intensity of 70 pnA. The secondary cocktail beam was separated and identified with the BigRIPS fragment separator and the ZeroDegree spectrometer. The unambiguous particle identification was achieved by measuring the energy loss, time of flight and magnetic rigidity event-by-event. The identified fragments were implanted in the CAITEN detector (Cylindrical Active Implantation Target for Efficient Nuclear-decay study). The main part of this detector is a 4 x 10{sup 4}-fold segmented plastic scintillator with the shape of a hollow cylinder. To reduce background events the scintillator was moved continuously in axial and vertical direction (similar to a tape-transporting system). Implantations and decays were correlated in time and space. {gamma}-rays were detected with three germanium clover detectors. For the first time {beta}-delayed gammas were measured in the neutron-rich isotopes {sup 36-38}Si. The status of the analysis and preliminary results including new half-life values and tentative level schemes for these very exotic nuclei are presented.

  5. Laser assisted nuclear decay spectroscopy: A new method for studying neutron-deficient francium

    CERN Document Server

    Lynch, Kara Marie

    2015-01-01

    Radioactive decay studies of rare isotopes produced at radioactive ion beam facilities have often been hindered by the presence of isobaric and isomeric contamination. The Collinear Resonance Ionization Spectroscopy (CRIS) experiment at ISOLDE, CERN uses laser radiation to stepwise excite and ionize an atomic beam in a particular isomeric state. Deflection of this selectively ionized beam of exotic nuclei, from the remaining neutral contaminants, allows ultra-sensitive detection of rare isotopes and nuclear structure measurements in background-free conditions.\

  6. Neutron radiation from medical electron accelerators

    International Nuclear Information System (INIS)

    McCall, R.C.

    1983-01-01

    A method is described using simple gold foils and relatively inexpensive moderators to measure neutron fluences, both fast nd thermal, which then can be converted to dose equivalent using a few simple formulas. The method is sensitive, easy to calibrate, and should work at most accelerators regardless of energy or room geometry

  7. Detector and dosimeter for neutrons and other radiation

    International Nuclear Information System (INIS)

    Apfel, R.E.

    1979-01-01

    A radiation detector and dosimeter is based on the fact that a sufficiently finely-dispersed liquid suspended in a host liquid of high viscosity or gel is stable at temperatures above its normal boiling point for long periods of time provided it is protected from contact with walls, or other types of initiators which can cause volatilization or vaporization of the droplets. Radiation, and particularly neutron radiation of sufficient energy and intensity on coming in contact with such droplets can trigger volatilization. The volume of vapor evolved can then serve as a measure of radiation intensity and dosage

  8. Vacuum decay in theories with symmetry breaking by radiative corrections

    International Nuclear Information System (INIS)

    Weinberg, E.J.

    1993-01-01

    The standard bounce formalism for calculating the decay rate of a metastable vacuum cannot be applied to theories in which the symmetry breaking is due to radiative corrections, because in such theories the tree-level action has no bounce solutions. In this paper I derive a modified formalism to deal with such cases. As in the usual case, the bubble nucleation rate may be written in the form Ae -B . To leading approximation, B is the bounce action obtained by replacing the tree-level potential by the leading one-loop approximation to the effective potential, in agreement with the generally adopted ad hoc remedy. The next correction to B (which is proportional to an inverse power of a small coupling) is given in terms of the next-to-leading term in the effective potential and the leading correction to the two-derivative term in the effective action. The corrections beyond these (which may be included in the prefactor) do not have simple expressions in terms of the effective potential and the other functions in the effective action. In particular, the scalar-loop terms which give an imaginary part to the effective potential do not explicitly appear; the corresponding effects are included in a functional determinant which gives a manifestly real result for the nucleation rate

  9. Beta decay heat following U-235, U-238 and Pu-239 neutron fission

    Science.gov (United States)

    Li, Shengjie

    1997-09-01

    This is an experimental study of beta-particle decay heat from 235U, 239Pu and 238U aggregate fission products over delay times 0.4-40,000 seconds. The experimental results below 2s for 235U and 239Pu, and below 20s for 238U, are the first such results reported. The experiments were conducted at the UMASS Lowell 5.5-MV Van de Graaff accelerator and 1-MW swimming-pool research reactor. Thermalized neutrons from the 7Li(p,n)7Be reaction induced fission in 238U and 239Pu, and fast neutrons produced in the reactor initiated fission in 238U. A helium-jet/tape-transport system rapidly transferred fission fragments from a fission chamber to a low background counting area. Delay times after fission were selected by varying the tape speed or the position of the spray point relative to the beta spectrometer that employed a thin-scintillator-disk gating technique to separate beta-particles from accompanying gamma-rays. Beta and gamma sources were both used in energy calibration. Based on low-energy(energies 0-10 MeV. Measured beta spectra were unfolded for their energy distributions by the program FERD, and then compared to other measurements and summation calculations based on ENDF/B-VI fission-product data performed on the LANL Cray computer. Measurements of the beta activity as a function of decay time furnished a relative normalization. Results for the beta decay heat are presented and compared with other experimental data and the summation calculations.

  10. Influence of fission product transport on delayed neutron precursors and decay heat sources in LMFBR accidents

    International Nuclear Information System (INIS)

    Apperson, C.E. Jr.

    1981-01-01

    A method is presented for studying the influence of fission product transpot on delayed neutron precursors and decay heat sources during Liquid Metal Fast Breeder Reactor (LMFBR) unprotected accidents. The model represents the LMFBR core as a closed homogeneous cell. Thermodynamic phase equilibrium theory is used to predict fission product mobility. Reactor kinetics behavior is analyzed by an extension of point kinetics theory. Group dependent delayed neutron precursor and decay heat source retention factors, which represent the fraction of each group retained in the fuel, are developed to link the kinetics and thermodynamics analysis. Application of the method to a highly simplified model of an unprotected loss-of-flow accident shows a time delay on the order of 10 ms is introduced in the predisassembly power history if fission product motion is considered when compared to the traditional transient solution. The post-transient influence of fission product transport calculated by the present model is a 24 percent reduction in the decay heat level in the fuel material which is similar to traditional approximations. Isotopes of the noble gases, Kr and Xe, and the elements I and Br are shown to be very mobile and are responsible for a major part of the observed effects. Isotopes of the elements Cs, Se, Rb, and Te were found to be moderately mobile and contribute to a lesser extent to the observed phenomena. These results obtained from the application of the described model confirm the initial hypothesis that sufficient fission product transport can occur to influence a transient. For these reasons, it is concluded that extension of this model into a multi-cell transient analysis code is warranted

  11. Intercomparison of radiation protection instrumentation in a pulsed neutron field

    Energy Technology Data Exchange (ETDEWEB)

    Caresana, M., E-mail: marco.caresana@polimi.it [Politecnico di Milano, CESNEF, Dipartimento di Energia, via Ponzio 34/3, 20133 Milano (Italy); Denker, A. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Esposito, A. [IFNF-LNF, FISMEL, via E. Fermi 40, 00044 Frascati (Italy); Ferrarini, M. [CNAO, Via Privata Campeggi, 27100 Pavia (Italy); Golnik, N. [Institute of Metrology and Biomedical Engineering, Warsaw University of Technology, Sw. A. Boboli 8, 02-525 Warsaw (Poland); Hohmann, E. [Paul Scherrer Institut (PSI), Radiation Metrology Section, CH-5232 Villigen PSI (Switzerland); Leuschner, A. [Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22603 Hamburg (Germany); Luszik-Bhadra, M. [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Manessi, G. [CERN, 1211 Geneva 23 (Switzerland); University of Liverpool, Department of Physics, L69 7ZE Liverpool (United Kingdom); Mayer, S. [Paul Scherrer Institut (PSI), Radiation Metrology Section, CH-5232 Villigen PSI (Switzerland); Ott, K. [Helmholtz-Zentrum Berlin, BESSYII, Albert-Einstein-Str.15, 12489 Berlin (Germany); Röhrich, J. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Silari, M. [CERN, 1211 Geneva 23 (Switzerland); Trompier, F. [Institute for Radiological Protection and Nuclear Safety, F-92262 Fontenay aux Roses (France); Volnhals, M.; Wielunski, M. [Helmholtz Zentrum München, Ingolstädter Landstr. 1, D-85764 Neuherberg (Germany)

    2014-02-11

    In the framework of the EURADOS working group 11, an intercomparison of active neutron survey meters was performed in a pulsed neutron field (PNF). The aim of the exercise was to evaluate the performances of various neutron instruments, including commercially available rem-counters, personal dosemeters and instrument prototypes. The measurements took place at the cyclotron of the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH. The cyclotron is routinely used for proton therapy of ocular tumours, but an experimental area is also available. For the therapy the machine accelerates protons to 68 MeV. The interaction of the proton beam with a thick tungsten target produces a neutron field with energy up to about 60 MeV. One interesting feature of the cyclotron is that the beam can be delivered in bursts, with the possibility to modify in a simple and flexible way the burst length and the ion current. Through this possibility one can obtain radiation bursts of variable duration and intensity. All instruments were placed in a reference position and irradiated with neutrons delivered in bursts of different intensity. The analysis of the instrument response as a function of the burst charge (the total electric charge of the protons in the burst shot onto the tungsten target) permitted to assess for each device the dose underestimation due to the time structure of the radiation field. The personal neutron dosemeters were exposed on a standard PMMA slab phantom and the response linearity was evaluated.

  12. Decay Study for the very Neutron-Rich Sn Nuclides, $^{135-140}$Sn Separated by Selective Laser Ionization

    CERN Multimedia

    2002-01-01

    %IS378 %title\\\\ \\\\ In this investigation, we wish to take advantage of chemically selective laser ionization to separate the very-neutron-rich Sn nuclides and determine their half-lives and delayed-neutron branches (P$_{n}$) using the Mainz $^{3}$He-delayed neutron spectrometer and close-geometry $\\gamma$-ray spectroscopy system. The $\\beta$-decay rates are dependent on a number of nuclear structure factors that may not be well described by models of nuclear structure developed for nuclides near stability. Determination of these decay properties will provide direct experimental data for r-process calculations and test the large number of models of nuclear structure for very-neutron rich Sn nuclides now in print.

  13. Decay spectroscopy of neutron-rich nuclei around {sup 37,38}Al

    Energy Technology Data Exchange (ETDEWEB)

    Steiger, Konrad [Physik-Department E12, Technische Universitaet Muenchen (Germany); Collaboration: CAITEN-Collaboration

    2013-07-01

    An experiment at RIBF (Radioactive Isotope Beam Factory at RIKEN, Japan) investigated N=20 nuclei above {sup 29}F and the midshell region around {sup 37}Al. These nuclei were produced by relativistic projectile fragmentation of a 345 AMeV {sup 48}Ca primary beam from the superconducting ring cyclotron SRC with an average intensity of 70 pnA. The secondary cocktail beam was separated and identified with the BigRIPS fragment separator and the ZeroDegree spectrometer. The identified fragments were implanted in the CAITEN detector (Cylindrical Active Implantation Target for Efficient Nuclear-decay study). The main part of this detector is a highly segmented plastic scintillator with the shape of a hollow cylinder. To reduce background decay events the scintillator was moved axially and vertically similar to a tape-transport system. Implantations and decays were correlated in time and space. For the first time β-delayed γ-rays were measured in the neutron-rich isotopes {sup 37,38}Si (with three germanium clover detectors). From β-γ-γ coincidences partial level schemes could be constructed. The results were compared to shell model calculations and a tentative assignment for spins and parities of the experimental level schemes was possible. Significantly more precise half-lives for the implanted nuclei were measured.

  14. β-decay spectroscopy of neutron-rich 160,161,162Sm isotopes

    Directory of Open Access Journals (Sweden)

    Patel Z.

    2016-01-01

    Full Text Available Neutron-rich 160,161,162Sm isotopes have been populated at the RIBF, RIKEN via β first time. β-coincident γ rays were observed in all three isotopes including γ rays from the isomeric decay of 160Sm and 162Sm. The isomers in 160Sm and 162Sm have previously been observed but have been populated via β decay for the first time. The isomeric state in 162Sm is assigned a 4−v72+[ 633 ]⊗v12−[ 521 ]${4^ - }v{{7 \\over 2}^ + }\\left[ {633} \\right] \\otimes v{{1 \\over 2}^ - }\\left[ {521} \\right]$ configuration based on the decay pattern. The level schemes of 160Sm and 162Sm are presented. The ground states in the parent nuclei 160Pm and 162Pm are both assigned a 6−v72+[633]⊗π52−[532]${6^ - }v{{7 \\over 2}^ + }\\left[ {633} \\right] \\otimes \\pi {{5 \\over 2}^ - }\\left[ {532} \\right]$ configuration based on the population of states in the daughter nuclei. Blocked BCS calculations were performed to further investigate the spin-parities of the ground states in 160Pm, 161Pm, and 162Pm, and the isomeric state in 162Sm

  15. Design, construction and characterization of a dosimeter for neutron radiation

    International Nuclear Information System (INIS)

    Souto, Eduardo de Brito

    2007-01-01

    An individual dosimeter for neutron-gamma mixed field dosimetry was design and developed aiming monitoring the increasing number of workers potentially exposed to neutrons. The proposed dosimeter was characterized to an Americium-Beryllium source spectrum and dose range of radiation protection interest (up to 20 mSv). Thermoluminescent albedo dosimetry and nuclear tracks dosimetry, traditional techniques found in the international literature, with materials of low cost and national production, were used. A commercial polycarbonate, named SS-1, was characterized for solid state tack detector application. The chemical etching parameters and the methodology of detectors evaluation were determined. The response of TLD-600, TLD-700 and SS-1 were studied and algorithms for dose calculation of neutron and gamma radiation of Americium- Beryllium sources were proposed. The ratio between thermal, albedo and fast neutrons responses, allows analyzing the spectrum to which the dosimeter was submitted and correcting the track detector response to variations in the radiation incidence angle. The new dosimeter is fully characterized, having sufficient performance to be applied as neutron dosimeter in Brazil. (author)

  16. Undergraduate experiments using the neutron radiation from californium-252

    International Nuclear Information System (INIS)

    Rossel, J.; Golecki, I.

    1976-01-01

    Three experiments designed to demonstrate and measure several properties of the neutron radiation emitted by a 3μg 252 Cf source are described. The experiments constitute a special project carried out by a third-year undergraduate student at the Institute of Physics of the University of Neuchatel. The 252 Cf source is enclosed in a shield which allows a pencil of fast neutrons to pass through a central tube, while reducing the ambient radiation below the tolerance level. The shield consists of layers of borated paraffin wax, iron and cadmium. The first experiment uses an air-alcohol diffusion cloud chamber for the demonstration of tracks of recoil protons produced by the neutrons. Semi-quantitative measurements of track lengths give the correct order of magnitude of the proton energies. In the second experiment a liquid scintillator detector is used to scan the beam profile across the radiation shield enclosing the source. A pulse-shape-discrimination system discriminates between neutrons and gamma photons. The third experiment makes use of the nuclear emulsion technique to study the neutron energy distribution of 252 Cf. Preliminary results are compared with published values. (author)

  17. Chromatin damage induced by fast neutrons or UV laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Radu, L.; Constantinescu, B.; Gazdaru, D.; Mihailescu, I

    2002-07-01

    Chromatin samples from livers of Wistar rats were subjected to fast neutron irradiation in doses of 10-100 Gy or to a 248 nm excimer laser radiation, in doses of 0.5-3 MJ.m{sup -2}. The action of the radiation on chromatin was monitored by chromatin intrinsic fluorescence and fluorescence lifetimes (of bound ethidium bromide to chromatin) and by analysing fluorescence resonance energy transfer between dansyl chloride and acridine orange coupled to chromatin. For the mentioned doses of UV excimer laser radiation, the action on chromatin was more intense than in the case of fast neutrons. The same types of damage are produced by the two radiations: acidic and basic destruction of chromatin protein structure, DNA strand breaking and the increase of the distance between DNA and proteins in chromatin. (author)

  18. Chromatin damage induced by fast neutrons or UV laser radiation

    International Nuclear Information System (INIS)

    Radu, L.; Constantinescu, B.; Gazdaru, D.; Mihailescu, I.

    2002-01-01

    Chromatin samples from livers of Wistar rats were subjected to fast neutron irradiation in doses of 10-100 Gy or to a 248 nm excimer laser radiation, in doses of 0.5-3 MJ.m -2 . The action of the radiation on chromatin was monitored by chromatin intrinsic fluorescence and fluorescence lifetimes (of bound ethidium bromide to chromatin) and by analysing fluorescence resonance energy transfer between dansyl chloride and acridine orange coupled to chromatin. For the mentioned doses of UV excimer laser radiation, the action on chromatin was more intense than in the case of fast neutrons. The same types of damage are produced by the two radiations: acidic and basic destruction of chromatin protein structure, DNA strand breaking and the increase of the distance between DNA and proteins in chromatin. (author)

  19. Prompt neutron decay constant for the Oak Ridge Research Reactor with 20 wt % 235U enriched fuel

    International Nuclear Information System (INIS)

    Ragan, G.E.; Mihalczo, J.T.

    1986-01-01

    This paper describes measurements of the prompt neutron decay constant at delayed criticality for the Oak Ridge Research Reactor (ORR) using 20 wt % 235 U enriched fuel and compares these measurements with similar measurements using 93.2 wt % 235 U enriched fuel. This reactor parameter is of interest because it affects the transient behavior of the reactor in prompt criticality accident situations. This experiment is part of a program to investigate the differences in the performance of research reactors fueled with highly enriched and low enriched uranium. The prompt neutron decay constants were obtained using noise analysis measurement techniques for a core with newly fabricated, unirradiated fuel elements

  20. Radioactive decay data tables: A handbook of decay data for application to radiation dosimetry and radiological assessments

    Science.gov (United States)

    Kocher, D. C.; Smith, J. S.

    Decay data are presented for approximately 500 radionuclides including those occurring naturally in the environment, those of potential importance in routine or accidental releases from the nuclear fuel cycle, those of current interest in nuclear medicine and fusion reactor technology, and some of those of interest to Committee 2 of the International Commission on Radiological Protection for the estimation of annual limits on intake via inhalation and ingestion for occupationally exposed individuals. Physical processes involved in radioactive decay which produce the different types of radiation observed, methods used to prepare the decay data sets for each radionuclide in the format of the computerized evaluated nuclear structure data file, the tables of radioactive decay data, and the computer code MEDLIST used to produce the tables are described. Applications of the data to problems of interest in radiation dosimetry and radiological assessments are considered as well as the calculations of the activity of a daughter radionuclide relative to the activity of its parent in a radioactive decay chain.

  1. Analysis of the WCLL European demo blanket concept in terms of activation and decay heat after exposure to neutron irradiation

    OpenAIRE

    Stankunas Gediminas; Tidikas Andrius

    2017-01-01

    This comparative paper describes the activation and decay heat calculations for water-cooled lithium-lead performed part of the EURO fusion WPSAE programme and specifications in comparison to other European DEMO blanket concepts on the basis of using a three-dimensional neutronics calculation model. Results are provided for a range of decay times of interest for maintenance activities, safety and waste management assessments. The study revealed that water-c...

  2. A new, passive dosemeter for gamma, beta and neutron radiations

    Energy Technology Data Exchange (ETDEWEB)

    Jones, L A; Stokes, R P, E-mail: rpstokes@dstl.gov.uk [Defence Science and Technology Laboratory, Environmental Sciences Department, Alverstoke, Gosport, Hants, PO12 2DL (United Kingdom)

    2011-03-01

    The Defence Science and Technology Laboratory (Dstl) provides personal radiation dosimetry to the UK Ministry of Defence. Dstl has recently developed a dosemeter that is based on a combination of thermoluminescent and etched-track detectors. The Dstl Combined Dosemeter is capable of assessing doses due to photons, beta particles and neutrons. This paper presents the laboratory type testing results for the Combined Dosemeter, and also describes the procedure for calibrating the dosemeter for use in workplace neutron fields. The Combined Dosemeter meets the type test requirements that are relevant to its intended applications, and gives neutron doses that are within 50% of the true dose in the workplaces in which it is used, even when the wearer has the potential to be exposed to a variety of neutron spectra (e.g. on board nuclear-powered submarines).

  3. A new, passive dosemeter for gamma, beta and neutron radiations

    International Nuclear Information System (INIS)

    Jones, L A; Stokes, R P

    2011-01-01

    The Defence Science and Technology Laboratory (Dstl) provides personal radiation dosimetry to the UK Ministry of Defence. Dstl has recently developed a dosemeter that is based on a combination of thermoluminescent and etched-track detectors. The Dstl Combined Dosemeter is capable of assessing doses due to photons, beta particles and neutrons. This paper presents the laboratory type testing results for the Combined Dosemeter, and also describes the procedure for calibrating the dosemeter for use in workplace neutron fields. The Combined Dosemeter meets the type test requirements that are relevant to its intended applications, and gives neutron doses that are within 50% of the true dose in the workplaces in which it is used, even when the wearer has the potential to be exposed to a variety of neutron spectra (e.g. on board nuclear-powered submarines).

  4. HSC5: synchrotron radiation and neutrons for cultural heritage studies

    International Nuclear Information System (INIS)

    Michel, Anne; Artioli, G.; Bleuet, P.; Cotte, M.; Tafforeau, P.; Susini, J.; Dumas, P.; Somogyl, A.; Cotte, M.; Kockelmann, W.; Kolar, J.; Areon, I.; Meden, A.; Strlie, M.; Pantos, M.; Vendrell, M.; Wess, T.; Gunneweg, J.

    2007-01-01

    Synchrotron and neutron sources offer recent and additional insight into the records of our cultural past. Over the last years, there has been an increasing demand for access to synchrotron radiation- and neutron-based techniques, and their applications in the fields of archaeological science and cultural heritage. The purpose of this Hercules Specialized Course is to give the participants an introduction to the basic principles of synchrotron radiation and neutron techniques (imaging, microscopy, diffraction, absorption and fluorescence, IR spectroscopy). The school provides cross-disciplinary examples illustrating the abilities of these techniques in a representative range of scientific cases concerning painting, archaeological artefacts, inks, pigments, fossils and the Dead Sea scrolls. This document gathers only the resumes of the lectures

  5. Moessbauer studies of hemoglobin in erythrocytes exposed to neutron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Niemiec, Katarzyna; Kaczmarska, Magdalena; Buczkowski, Mateusz [AGH University, Faculty of Physics and Computer Science, Department of Medical Physics and Biophysics (Poland); Fornal, Maria [Collegium Medicum, Jagiellonian University, Department of Internal Medicine and Gerontology (Poland); Pohorecki, Wladyslaw [AGH University, Faculty of Energy and Fuels (Poland); Matlak, Krzysztof; Korecki, Jozef [AGH University, Faculty of Physics and Computer Science, Department of Solid State Physics (Poland); Grodzicki, Tomasz [Collegium Medicum, Jagiellonian University, Department of Internal Medicine and Gerontology (Poland); Burda, Kvetoslava, E-mail: kvetoslava.burda@fis.agh.edu.pl [AGH University, Faculty of Physics and Computer Science, Department of Medical Physics and Biophysics (Poland)

    2012-03-15

    We studied radiation effects on the stability of various states of hemoglobin (Hb) in red blood cells (RBC) irradiated with a very low dose of neutron rays, 50 {mu}Gy. We investigated RBCs isolated from blood of healthy donors. Moessbauer spectroscopy was applied to monitor different forms of Hb. Our results show, for the first time, that oxyhemoglobin (OxyHb) and deoxyhemoglobin (DeoxyHb) are two Hb forms sensitive to such a low neutron radiation. Both Hbs change into a new Hb form (Hb{sub irr}). Additionally, OxyHb transfers into HbOH/H{sub 2}O, which under our experimental conditions is resistant to the action of neutron rays.

  6. HSC5: synchrotron radiation and neutrons for cultural heritage studies

    Energy Technology Data Exchange (ETDEWEB)

    Michel, Anne [Institut Neel - CNRS, 38 - Grenoble (France); Artioli, G. [Padova Univ. (Italy); Bleuet, P.; Cotte, M.; Tafforeau, P.; Susini, J. [European Synchrotron Radiation Facility, 38 - Grenoble (France); Dumas, P.; Somogyl, A. [SOLEIL Synchrotron, 91 - Gif sur Yvette (France); Cotte, M. [Centre de Recherche et de Restauration des Musees de France, UMR171, 75 - Paris (France)]|[European Synchrotron Radiation Facility, 38 - Grenoble (France); Kockelmann, W. [Science and Technology Facilities Council, Rutherford Appleton Lab. (United Kingdom); Kolar, J. [Ljubljana Univ., Morana RTD, Slovenia, Faculty of Chemistry and Chemical Technology (Slovenia); Areon, I. [Nova Gorica Univ. (Slovenia); Meden, A.; Strlie, M. [Ljubljana Univ., Faculty of Chemistry and Chemical Technology (Slovenia); Pantos, M. [Daresbury Laboratory, Warrington (United Kingdom); Vendrell, M. [Barcelona Univ., dept. of Crystallography and Mineralogy (Spain); Wess, T. [Cardiff Univ., School of Optometry and Institute of Vision (Ireland); Gunneweg, J. [Hebrew Univ., Jerusalem (Israel)

    2007-07-01

    Synchrotron and neutron sources offer recent and additional insight into the records of our cultural past. Over the last years, there has been an increasing demand for access to synchrotron radiation- and neutron-based techniques, and their applications in the fields of archaeological science and cultural heritage. The purpose of this Hercules Specialized Course is to give the participants an introduction to the basic principles of synchrotron radiation and neutron techniques (imaging, microscopy, diffraction, absorption and fluorescence, IR spectroscopy). The school provides cross-disciplinary examples illustrating the abilities of these techniques in a representative range of scientific cases concerning painting, archaeological artefacts, inks, pigments, fossils and the Dead Sea scrolls. This document gathers only the resumes of the lectures.

  7. Polycrystalline Materials as a Cold Neutron and Gamma Radiation Filter

    International Nuclear Information System (INIS)

    Habib, N.

    2009-01-01

    The total neutron cross-section of polycrystalline beryllium, graphite and iron has been calculated beyond their cut-off wavelength using a general formula. The computer Cold Filter code was developed in order to provide the required calculations. The code also permits the calculation of attenuation of reactor gamma radiation, The calculated neutron transmissions through polycrystalline Be graphite and iron at different temperatures were compared with the experimental data measured at the ETRR-1 reactor using two TOF spectrometers. An overall agreement is obtained between the formula fits and experimental data at different temperatures. A feasibility study is carried on using polycrystalline Be, graphite and iron an efficient filter for cold neutrons and gamma radiation.

  8. Neutron diffraction measurements at the INES diffractometer using a neutron radiative capture based counting technique

    Energy Technology Data Exchange (ETDEWEB)

    Festa, G. [Centro NAST, Universita degli Studi di Roma Tor Vergata, Roma (Italy); Pietropaolo, A., E-mail: antonino.pietropaolo@roma2.infn.it [Centro NAST, Universita degli Studi di Roma Tor Vergata, Roma (Italy); Grazzi, F.; Barzagli, E. [CNR-ISC Firenze (Italy); Scherillo, A. [CNR-ISC Firenze (Italy); ISIS facility Rutherford Appleton Laboratory (United Kingdom); Schooneveld, E.M. [ISIS facility Rutherford Appleton Laboratory (United Kingdom)

    2011-10-21

    The global shortage of {sup 3}He gas is an issue to be addressed in neutron detection. In the context of the research and development activity related to the replacement of {sup 3}He for neutron counting systems, neutron diffraction measurements performed on the INES beam line at the ISIS pulsed spallation neutron source are presented. For these measurements two different neutron counting devices have been used: a 20 bar pressure squashed {sup 3}He tube and a Yttrium-Aluminum-Perovskite scintillation detector. The scintillation detector was coupled to a cadmium sheet that registers the prompt radiative capture gamma rays generated by the (n,{gamma}) nuclear reactions occurring in cadmium. The assessment of the scintillator based counting system was done by performing a Rietveld refinement analysis on the diffraction pattern from an ancient Japanese blade and comparing the results with those obtained by a {sup 3}He tube placed at the same angular position. The results obtained demonstrate the considerable potential of the proposed counting approach based on the radiative capture gamma rays at spallation neutron sources.

  9. Neutron capture in borehole logging

    International Nuclear Information System (INIS)

    Randall, R.R.

    1981-01-01

    The use is described of a pulsed source of fast neutrons and a radiation detector to measure the thermal neutron population decay rate in a well logging instrument. The macroscopic neutron absorption cross-section is calculated by taking the natural logarithm of the ratio of the detected radiation counts occurring within two measurement intervals of fixed duration and starting at a fixed time after a neutron burst. (U.K.)

  10. Buckling analysis of a cylindrical shell, under neutron radiation environment

    International Nuclear Information System (INIS)

    Arani, A. Ghorbanpour; Ahmadi, M.; Ahmadi, A.; Rastgoo, A.; Sepyani, H.A.

    2012-01-01

    Highlights: ► The work investigates the buckling of a shell in the neutron radiation environment. ► Radiation induced porosity in elastic materials affects the material's properties. ► The data based technique was used to determine the volume fraction porosity. ► The theoretical formulations are presented based on the classical shell theory (CST). ► It was concluded that both T and neutron induced swelling have significant effects. - Abstract: This research investigates the buckling of a cylindrical shell in the neutron radiation environment, subjected to combined static and periodic axial forces. Radiation induced porosity in elastic materials affects the thermal, electrical and mechanical properties of the materials. In this study, the data based technique was used to determine the volume fraction porosity, P, of shell material. A least-squares fit of the Young's module data yielded the estimated Young's modulus. The shell assumed made of iron irradiated in the range of 2–15e−7 dPa/s at 345–650 °C and theoretical formulations are presented based on the classical shell theory (CST). The research deals with the problem theoretically; keeping in mind that one means of generating relevant design data is to investigate prototype structures. A parametric study is followed and the stability of shell is discussed. It is concluded that both temperature and neutron induced swelling have significant effects on the buckling load.

  11. Semiconductor dosimetry system for gamma and neutron radiation

    International Nuclear Information System (INIS)

    Savic, Z.; Pavlovic, Z.

    1995-01-01

    The semiconductor dosimetry system for gamma and neutron radiation based on pMOS transistor and PIN diode is described. It is intended for tactical or accidental personal dosimetry. The production steps are given. The temperature, dose and time (fading) response are reported. Hardware and software requirements which are needed for obtaining the desired measurement error are pointed. (author)

  12. EVIDOS: Individual dosimetry in mixed neutron and photon radiation fields

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2006-01-01

    The EVIDOS project (partly funded by the European Commission RTD Programme: Nuclear Energy, Euratom Framework Programme V, 1998-2002, Contract No FIKR-CT-2001-00175) aimed at improving individual monitoring in mixed neutron-photon radiation fields by evaluating the performance of routine and novel personal dosimeters for mixed radiation, and by giving guidelines for deriving sufficiently accurate values of personal dose equivalent from the readings of area survey instruments and dosimeters. The main objective of EVIDOS was to evaluate different methods for individual dosimetry in mixed neutron-photon work-places in nuclear industry. This implied a determination of the capabilities and limitations of personal dosimeters and the establishment of methods to enable sufficiently accurate values of personal dose equivalent from spectrometers, area survey instruments and routine personal dosimeters. Also novel electronic personal dosimeters were investigated. To this end spectrometric and dosimetric investigations in selected representative workplaces in nuclear industry where workers can receive significant neutron doses were performed. As part of this project, a number of tasks were executed, in particular: (1) the determination of the energy and direction distribution of the neutron fluence; (2) the derivation of the (conventionally true) values of radiation protection quantities; (3) the determination of the readings of routine and innovative personal dosimeters and of area monitors; and (4) the comparison between dosimeter readings and values of the radiation protection quantities

  13. Options for the modified radiation weighting factor of neutrons

    International Nuclear Information System (INIS)

    Kellerer, A. M.; Leuthold, G.; Mares, V.; Schraube, H.

    2004-01-01

    The recent ICRP Report 92 has noted that the current radiation weighting factor, w R , depends on the energy of the incident neutrons in a manner that differs substantially from the dependence, which results from the current convention, Q(L). At all neutron energies, but most conspicuously below 1 MeV, the values of w R exceed those of the effective quality factor, q E . The discrepancy is largely due to the fact that - in the absence of computed values of the effective quality factor for neutrons - w R has been patterned after the values of the ambient quality factor, which accounts insufficiently for the low-linear energy transfer (LET) gamma ray component from neutron capture in the human body. There are different options to remove the discrepancy. Option 1 is to reduce w R substantially at all neutron energies to make it equal to q E for a standard condition, such as isotropic incidence of the neutrons. Since such a reduction may cause problems in those countries where the current w R values are already legally implemented, ICRP 92 has proposed what is here termed Option 2. It recommended to replace Q(L) by the increased value 1.6 Q(L) - 0.6 and, accordingly, to make the radiation weighting factor equal to 1.6 q E - 0.6. With Option 2 the radiation weighting factor needs to be decreased appreciably at low neutron energies, but for fission neutron spectra the overall changes are minor. To guide - regardless which option is chosen - the selection of the numerical values, the effective quality factor, q E , is computed here for different directional distributions of neutrons incident on the anthropomorphic phantoms ADAM and EVA. None of the sex averaged numerical values is found to deviate much from those for isotropic incidence. Isotropic incidence can, thus, be used as an adequate standard condition. A numerical approximation is proposed for the standard q E that is nearly equivalent to a formula invoked by ICRP 92, but is somewhat simpler and provides realistic

  14. Individual neutron monitoring in workplaces with mixed neutron/proton radiation

    International Nuclear Information System (INIS)

    Bolognese-Milsztajn, T.; Bartlett, D.; Boschung, M.; Coeck, M.; Curzio, G.; D'Errico, F.; Fiechtner, A.; Giusti, V.; Gressier, V.; Kylloenen, J.; Lacoste, V.; Lindborg, L.; Luszik-Bhadra, M.; Molinos, C.; Pelcot, G.; Reginatto, M.; Schuhmacher, H.; Tanner, R.; Vanhavere, F.; Derdau, D.

    2004-01-01

    EVIDOS ('evaluation of individual dosimetry in mixed neutron and photon radiation fields') is an European Commission (EC)-sponsored project that aims at a significant improvement of radiation protection dosimetry in mixed neutron/photon fields via spectrometric and dosimetric investigations in representative workplaces of the nuclear industry. In particular, new spectrometry methods are developed that provide the energy and direction distribution of the neutron fluence from which the reference dosimetric quantities are derived and compared to the readings of dosemeters. The final results of the project will be a comprehensive set of spectrometric and dosimetric data for the workplaces and an analysis of the performance of dosemeters, including novel electronic dosemeters. This paper gives an overview of the project and focuses on the results from measurements performed in calibration fields with broad energy distributions (simulated workplace fields) and on the first results from workplaces in the nuclear industry, inside a boiling water reactor and around a spent fuel transport cask. (authors)

  15. Study of the η'→π+π-γ radiative decay

    International Nuclear Information System (INIS)

    Bityukov, S.I.; Borisov, G.V.; Dorofeev, V.A.

    1990-01-01

    The radiative decay η → π + π - γ has been studied the statistics of ∼2000 events. Different ways of desorbing mππ distribution in this decay are considered. It is shown that if the dominating contribution to this process is made by the decay channel η'→ργ, then the generally accepted ways of describing the ρ peak do not agree with experimental data

  16. Response of CsI:Pb Scintillator Crystal to Neutron Radiation

    Science.gov (United States)

    Costa Pereira, Maria da Conceição; Filho, Tufic Madi; Berretta, José Roberto; Náhuel Cárdenas, José Patrício; Iglesias Rodrigues, Antonio Carlos

    2018-01-01

    The helium-3 world crisis requires a development of new methods of neutron detection to replace commonly used 3He proportional counters. In the past decades, great effort was made to developed efficient and fast scintillators to detect radiation. The inorganic scintillator may be an alternative. Inorganic scintillators with much higher density should be selected for optimal neutron detection efficiency taking into consideration the relevant reactions leading to light emission. These detectors should, then, be carefully characterized both experimentally and by means of advanced simulation code. Ideally, the detector should have the capability to separate neutron and gamma induced events either by amplitude or through pulse shape differences. As neutron sources also generate gamma radiation, which can interfere with the measurement, it is necessary that the detector be able to discriminate the presence of such radiation. Considerable progress has been achieved to develop new inorganic scintillators, in particular increasing the light output and decreasing the decay time by optimized doping. Crystals may be found to suit neutron detection. In this report, we will present the results of the study of lead doped cesium iodide crystals (CsI:Pb) grown in our laboratory, using the vertical Bridgman technique. The concentration of the lead doping element (Pb) was studied in the range 5x10-4 M to 10-2 M . The crystals grown were subjected to annealing (heat treatment). In this procedure, vacuum of 10-6 mbar and continuous temperature of 350°C, for 24 hours, were employed. In response to neutron radiation, an AmBe source with energy range of 1 MeV to 12 MeV was used. The activity of the AmBe source was 1Ci Am. The fluency was 2.6 x 106 neutrons/second. The operating voltage of the photomultiplier tube was 1700 V; the accumulation time in the counting process was 600 s and 1800 s. The scintillator crystals used were cut with dimensions of 20 mm diameter and 10 mm height.

  17. Secondary Neutron Production from Space Radiation Interactions: Advances in Model and Experimental Data Base Development

    Science.gov (United States)

    Heilbronn, Lawrence H.; Townsend, Lawrence W.; Braley, G. Scott; Iwata, Yoshiyuki; Iwase, Hiroshi; Nakamura, Takashi; Ronningen, Reginald M.; Cucinotta, Francis A.

    2003-01-01

    For humans engaged in long-duration missions in deep space or near-Earth orbit, the risk from exposure to galactic and solar cosmic rays is an important factor in the design of spacecraft, spacesuits, and planetary bases. As cosmic rays are transported through shielding materials and human tissue components, a secondary radiation field is produced. Neutrons are an important component of that secondary field, especially in thickly-shielded environments. Calculations predict that 50% of the dose-equivalent in a lunar or Martian base comes from neutrons, and a recent workshop held at the Johnson Space Center concluded that as much as 30% of the dose in the International Space Station may come from secondary neutrons. Accelerator facilities provide a means for measuring the effectiveness of various materials in their ability to limit neutron production, using beams and energies that are present in cosmic radiation. The nearly limitless range of beams, energies, and target materials that are present in space, however, means that accelerator-based experiments will not provide a complete database of cross sections and thick-target yields that are necessary to plan and design long-duration missions. As such, accurate nuclear models of neutron production are needed, as well as data sets that can be used to compare with, and verify, the predictions from such models. Improvements in a model of secondary neutron production from heavy-ion interactions are presented here, along with the results from recent accelerator-based measurements of neutron-production cross sections. An analytical knockout-ablation model capable of predicting neutron production from high-energy hadron-hadron interactions (both nucleon-nucleus and nucleus-nucleus collisions) has been previously developed. In the knockout stage, the collision between two nuclei result in the emission of one or more nucleons from the projectile and/or target. The resulting projectile and target remnants, referred to as

  18. Studying radiative B decays with the Atlas detector; Etude des desintegrations radiatives des mesons B dans le detecteur ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Viret, S

    2004-09-01

    This thesis is dedicated to the study of radiative B decays with the ATLAS detector at the LHC (large hadron collider). Radiative decays belong to the rare decays family. Rare decays transitions involve flavor changing neutral currents (for example b {yields} s{gamma}), which are forbidden at the lowest order in the Standard Model. Therefore these processes occur only at the next order, thus involving penguin or box diagrams, which are very sensitive to 'new physics' contributions. The main goal of our study is to show that it would be possible to develop an online selection strategy for radiative B decays with the ATLAS detector. To this end, we have studied the treatment of low energy photons by the ATLAS electromagnetic calorimeter (ECal). Our analysis shows that ATLAS ECal will be efficient with these particles. This property is extensively used in the next section, where a selection strategy for radiative B decays is proposed. Indeed, we look for a low energy region of interest in the ECal as soon as the level 1 of the trigger. Then, photon identification cuts are performed in this region at level 2. However, a large part of the proposed selection scheme is also based on the inner detector, particularly at level 2. The final results show that large amounts of signal events could be collected in only one year by ATLAS. A preliminary significance (S/{radical}B) estimation is also presented. Encouraging results concerning the observability of exclusive radiative B decays are obtained. (author)

  19. Studying radiative B decays with the Atlas detector; Etude des desintegrations radiatives des mesons B dans le detecteur ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Viret, S

    2004-09-01

    This thesis is dedicated to the study of radiative B decays with the ATLAS detector at the LHC (large hadron collider). Radiative decays belong to the rare decays family. Rare decays transitions involve flavor changing neutral currents (for example b {yields} s{gamma}), which are forbidden at the lowest order in the Standard Model. Therefore these processes occur only at the next order, thus involving penguin or box diagrams, which are very sensitive to 'new physics' contributions. The main goal of our study is to show that it would be possible to develop an online selection strategy for radiative B decays with the ATLAS detector. To this end, we have studied the treatment of low energy photons by the ATLAS electromagnetic calorimeter (ECal). Our analysis shows that ATLAS ECal will be efficient with these particles. This property is extensively used in the next section, where a selection strategy for radiative B decays is proposed. Indeed, we look for a low energy region of interest in the ECal as soon as the level 1 of the trigger. Then, photon identification cuts are performed in this region at level 2. However, a large part of the proposed selection scheme is also based on the inner detector, particularly at level 2. The final results show that large amounts of signal events could be collected in only one year by ATLAS. A preliminary significance (S/{radical}B) estimation is also presented. Encouraging results concerning the observability of exclusive radiative B decays are obtained. (author)

  20. Study of the radiative decay K+→μ+νγ

    International Nuclear Information System (INIS)

    Akiba, Y.; Ishikawa, T.; Iwasaki, M.

    1985-01-01

    The radiative decay K + →μ + νγ has been studied by a high-resolution magnetic spectrometer combined with a NaI(Tl) photon detector system. The momentum spectrum of muon from this decay mode was measured in the region 214.5 -3

  1. Radiative corrections for semileptonic decays of hyperons: the 'model independent' part

    International Nuclear Information System (INIS)

    Toth, K.; Szegoe, K.; Margaritis, T.

    1984-04-01

    The 'model independent' part of the order α radiative correction due to virtual photon exchanges and inner bremsstrahlung is studied for semileptonic decays of hyperons. Numerical results of high accuracy are given for the relative correction to the branching ratio, the electron energy spectrum and the (Esub(e),Esub(f)) Dalitz distribution in the case of four different decays. (author)

  2. Radiative E1-decay of charmonium 1P1 level within sum rules of quantum chromodynamics

    International Nuclear Information System (INIS)

    Martynenko, A.P.

    1991-01-01

    Analysis of radiative decay of 1 P 1 → 1 S 0 + γ charmonium within sum rules of quantum chromodynamics was conducted. The sum rule, taking account of gluon exponential correction, was obtained, and width of Χ → η c + γ decay was calculated

  3. studies of radiative penguin decays at BaBar (*) + - * -6 * ' * * * -E ...

    Indian Academy of Sciences (India)

    We summarize results on a number of observations of penguin dominated radiative decays of the B meson. Such decays are forbidden at tree level and proceed via electroweak loops. As such they may be sensitive to physics beyond the standard model. The observations have been made at the BaBar experiment at PEP-II, ...

  4. Decay Curves and Half-Lives of Gamma-Emitting States from a Study of Prompt Fission Gamma Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Albinsson, H [Chalmers Univ. of Technology, Goeteborg (SE)

    1971-04-15

    Measurements were made on the time distributions of the prompt gamma radiation emitted from fragments in the thermal-neutron induced fission of 235U. The gamma radiation emitted during different time intervals after the fission event was studied with the help of a collimator, the position of which was changed along the path of the fragments. In this way decay curves were obtained from which half-lives could be estimated. Time components with half-lives of 7.5, 18 and 60 ps were found and their relative intensities were calculated. Half-lives and associated intensities are in good agreement with earlier data from uranium and californium fission. Problems involved in this type of study are discussed. The collimator technique has proved to be effective for determination of half lives down to less than 10 ps

  5. Decay of neutron-rich Mn nuclides and deformation of heavy Fe isotopes

    CERN Document Server

    Hannawald, M; Wöhr, A; Walters, W B; Kratz, K L; Fedosseev, V; Mishin, V I; Böhmer, W; Pfeiffer, B; Sebastian, V; Jading, Y; Köster, U; Lettry, Jacques; Ravn, H L

    1999-01-01

    The use of chemically selective laser ionization combined with beta-delayed neutron counting at CERN/ISOLDE has permitted identification and half-life measurements for 623-ms Mn-61 up through 14-ms Mn-69. The measured half-lives are found to be significantly longer near N=40 than the values calculated with a QRPA shell model using ground-state deformations from the FRDM and ETFSI models. Gamma-ray singles and coincidence spectroscopy has been performed for Mn-64 and Mn-66 decays to levels of Fe-64 and Fe-66, revealing a significant drop in the energy of the first 2+ state in these nuclides that suggests an unanticipated increase in collectivity near N=40.

  6. Repair of radiation damage caused by cyclotron-produced neutrons

    International Nuclear Information System (INIS)

    Martins, B.I.

    1979-01-01

    Hall et al. present experimental data on repair of sublethal damage in cultured mammalian cells exposed to 35 MeV neutrons and 60 Co γ rays. Hall and Kraljevic present experimental data on repair of potentially lethal damage in cultured mammalian cells exposed to 35 MeV neutrons and 210 kVp x rays. These results of Hall et al. are very difficult to explain from basic concepts in radiobiology. Contrary to Rossi, these data do not support his thesis that repair of radiation damage is dose-dependent and linear energy transfer independent. Nor do these results meet the expectations of multitarget-single hit theory which would require dose-independent repair equal to n. The observation of the same extrapolation number for neutrons and for x rays is also surprising. From the point of view of radiotherapy, the doses of interest are about 140 rad for neutrons and about 300 rad for x rays. There are no data for repair of potentially lethal damage below 800 rad for x rays and 400 rad for neutrons. The difference in survival between single and split dose is negligible up to a total of about 600 rad of x rays or of neutrons. These data of Hall et al. therefore have little significance to radiotherapists and are an enigma to radiobiologists

  7. Radiative neutron capture: Hauser Feshbach vs. statistical resonances

    Energy Technology Data Exchange (ETDEWEB)

    Rochman, D., E-mail: dimitri-alexandre.rochman@psi.ch [Reactor Physics and Systems Behavior Laboratory, Paul Scherrer Institute, Villigen (Switzerland); Goriely, S. [Institut d' Astronomie et d' Astrophysique, CP-226, Université Libre de Bruxelles, 1050 Brussels (Belgium); Koning, A.J. [Nuclear Data Section, IAEA, Vienna (Austria); Uppsala University, Uppsala (Sweden); Ferroukhi, H. [Reactor Physics and Systems Behavior Laboratory, Paul Scherrer Institute, Villigen (Switzerland)

    2017-01-10

    The radiative neutron capture rates for isotopes of astrophysical interest are commonly calculated on the basis of the statistical Hauser Feshbach (HF) reaction model, leading to smooth and monotonically varying temperature-dependent Maxwellian-averaged cross sections (MACS). The HF approximation is known to be valid if the number of resonances in the compound system is relatively high. However, such a condition is hardly fulfilled for keV neutrons captured on light or exotic neutron-rich nuclei. For this reason, a different procedure is proposed here, based on the generation of statistical resonances. This novel technique, called the “High Fidelity Resonance” (HFR) method is shown to provide similar results as the HF approach for nuclei with a high level density but to deviate and be more realistic than HF predictions for light and neutron-rich nuclei or at relatively low sub-keV energies. The MACS derived with the HFR method are systematically compared with the traditional HF calculations for some 3300 neutron-rich nuclei and shown to give rise to significantly larger predictions with respect to the HF approach at energies of astrophysical relevance. For this reason, the HF approach should not be applied to light or neutron-rich nuclei. The Doppler broadening of the generated resonances is also studied and found to have a negligible impact on the calculated MACS.

  8. Recent activities for β-decay half-lives and β-delayed neutron emission of very neutron-rich isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Dillmann, Iris [TRIUMF, Vancouver BC, V6T 2A3, Canada and GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Abriola, Daniel [Laboratorio Tandar, Comisión Nacional de Energía Atómica, B1650KINA, San Martín, Buenos Aires (Argentina); Singh, Balraj [Department of Physics and Astronomy, McMaster University, Hamilton ON, L8S 4M1 (Canada)

    2014-05-02

    Beta-delayed neutron (βn) emitters play an important, two-fold role in the stellar nucleosynthesis of heavy elements in the 'rapid neutron-capture process' (r process). On one hand they lead to a detour of the material β-decaying back to stability. On the other hand, the released neutrons increase the neutron-to-seed ratio, and are re-captured during the freeze-out phase and thus influence the final solar r-abundance curve. A large fraction of the isotopes inside the r-process reaction path are not yet experimentally accessible and are located in the (experimental) 'Terra Incognita'. With the next generation of fragmentation and ISOL facilities presently being built or already in operation, one of the main motivation of all projects is the investigation of these very neutron-rich isotopes. A short overview of one of the planned programs to measure βn-emitters at the limits of the presently know isotopes, the BRIKEN campaign (Beta delayed neutron emission measurements at RIKEN) will be given. Presently, about 600 β-delayed one-neutron emitters are accessible, but only for a third of them experimental data are available. Reaching more neutron-rich isotopes means also that multiple neutron-emission becomes the dominant decay mechanism. About 460 β-delayed two-, three-or four-neutron emitters are identified up to now but for only 30 of them experimental data about the neutron branching ratios are available, most of them in the light mass region below A=30. The International Atomic and Energy Agency (IAEA) has identified the urgency and picked up this topic recently in a 'Coordinated Research Project' on a 'Reference Database for Beta-Delayed Neutron Emission Data'. This project will review, compile, and evaluate the existing data for neutron-branching ratios and half-lives of β-delayed neutron emitters and help to ensure a reliable database for the future discoveries of new isotopes and help to constrain astrophysical and

  9. Calibration of a special neutron dosemeter based on solid-state track detectors and fission radiators in various neutron fields

    International Nuclear Information System (INIS)

    Doerschel, B.; Krusche, M.; Schuricht, V.

    1980-01-01

    The calibration of a personnel neutron dosemeter in different neutron fields is described. The badge-like dosemeter contains 5 detectors: polycarbonate foil (10 μm, Makrofol KG), 232 Th, natural uranium, natural uranium with boron, and natural uranium with cadmium. Detector sensitivity and calibration factors have been calculated and measured in radiation fields of 252 Cf fission neutrons, WWR-S reactor neutrons with and without Cd and Fe shielding, 3-MeV (d,t) generator neutrons, and 238 PuBe neutrons. Measurement range and achievable accuracy are discussed from the point of view of applying the dosemeter in routine and emergency uses

  10. Measurement of the electron-antineutrino angular correlation coefficient a in neutron beta decay with the spectrometer aSPECT

    International Nuclear Information System (INIS)

    Petzoldt, G.

    2007-01-01

    In the four beam times we performed at the FRM-II, we were able to show that the spectrometer works in principle and that a determination of a with it is possible. A set of routines has been written for decoding and analyzing the raw data. The routines are written in C using the ROOT libraries and can be easily adapted or expanded. We have found a reliable way to extract the proton count rates from the data by building pulseheight spectra for each measurement, subtracting background measurements from those and fitting the resulting peak with a Gaussian. The background of the measurements was studied in detail. The background caused by electrons from neutron decay is very well understood and conforms quantitatively to our expectation. Due to the spatial resolution of our detector and the time resolution provided by our DAQ electronics, we were able to study correlated electron-proton pairs from one neutron decay event. They form a clearly visible peak in a time- and channel-distance spectrum, which can be shifted in the channel-dimension by varying the voltages applied to the lower and upper E x B electrodes. Performing a pulseheight analysis for both involved particles allowed us to obtain a fairly clean energy spectrum of the background caused by electrons from neutron decay in our detector. Using these correlations for data analysis may be of interest for future neutron decay experiments which use segmented detectors. (orig.)

  11. Measurement of the electron-antineutrino angular correlation coefficient a in neutron beta decay with the spectrometer aSPECT

    Energy Technology Data Exchange (ETDEWEB)

    Petzoldt, G.

    2007-08-29

    In the four beam times we performed at the FRM-II, we were able to show that the spectrometer works in principle and that a determination of a with it is possible. A set of routines has been written for decoding and analyzing the raw data. The routines are written in C using the ROOT libraries and can be easily adapted or expanded. We have found a reliable way to extract the proton count rates from the data by building pulseheight spectra for each measurement, subtracting background measurements from those and fitting the resulting peak with a Gaussian. The background of the measurements was studied in detail. The background caused by electrons from neutron decay is very well understood and conforms quantitatively to our expectation. Due to the spatial resolution of our detector and the time resolution provided by our DAQ electronics, we were able to study correlated electron-proton pairs from one neutron decay event. They form a clearly visible peak in a time- and channel-distance spectrum, which can be shifted in the channel-dimension by varying the voltages applied to the lower and upper E x B electrodes. Performing a pulseheight analysis for both involved particles allowed us to obtain a fairly clean energy spectrum of the background caused by electrons from neutron decay in our detector. Using these correlations for data analysis may be of interest for future neutron decay experiments which use segmented detectors. (orig.)

  12. Experimental investigation of decay properties of neutron deficient $^{116-118}$Ba isotopes and test of $^{112-115}$Ba beam counts

    CERN Multimedia

    We propose to study decay of neutron deficient isotopes $^{116-118}$Ba using Double Sided Silicon Strip Detector (DSSSD). To study delayed-proton and $\\alpha$-decay branching ratios of $^{116-118}$Ba are of special interest because of their vicinity to the proton drip line. The nuclear life-times and properties of the proton unstable states of Cs isotopes, populated through decay of $^{116-118}$Ba isotopes will be measured. In addition to that we propose beam development of $^{112-115}$Ba to study exotic decay properties of these neutron deficient nuclei and to search for super-allowed $\\alpha$-decay in future.

  13. Neutron density decay constant in a non-multiplying lattice of finite size

    International Nuclear Information System (INIS)

    Deniz, V.C.

    1965-01-01

    This report presents a general theory, using the integral transport method, for obtaining the neutron density decay constant in a finite non-multiplying lattice. The theory is applied to obtain the expression for the diffusion coefficient. The case of a homogeneous medium with 1/v absorption and of finite size in all directions is treated in detail, assuming an isotropic scattering law. The decay constant is obtained up to the B 6 term. The expressions for the diffusion coefficient and for the diffusion cooling coefficient are the same as those obtained for a slab geometry by Nelkin, using the expansion in spherical harmonics of the Fourier transform in the spatial variable. Furthermore, explicit forms are obtained for the flux and the current. It is shown that the deviation of the actual flux from a Maxwellian is the flux generated in the medium, extended to infinity and deprived of its absorbing power, by various sources, each of which has a zero integral over all velocities. The study of the current permits the generalization of Fick's law. An independent integral method, valid for homogeneous media, is also presented. (author) [fr

  14. Decay studies and mass measurements on isobarically pure neutron-rich Hg and Tl isotopes

    CERN Multimedia

    Schweikhard, L C; Savreux, R P; Hager, U D K; Beck, D; Blaum, K

    2007-01-01

    We propose to perform mass measurements followed by $\\beta$- and $\\gamma$-decay studies on isobarically pure beams of neutron-rich Hg and Tl isotopes, which are very poorly known due to a large contamination at ISOL-facilities with surface-ionised francium. The aim is to study the binding energies of mother Hg and Tl nuclides, as well as the energies, spins and parities of the excited and ground states in the daughter Tl and Pb isotopes. The proposed studies will address a new subsection of the nuclear chart, with Z 126, where only 9 nuclides have been observed so far. Our studies will provide valuable input for mass models and shell-model calculations: they will probe the proton hole-neutron interaction and will allow to refine the matrix elements for the two-body residual interaction. Furthermore, they also give prospects for discovering new isomeric states or even new isotopes, for which the half-lives are predicted in the minute- and second-range.\\\\ To reach the isobaric purity, the experiments will be p...

  15. Delayed neutron fraction and prompt decay constant measurement in the MINERVE reactor using the PSI instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Perret, Gregory [Paul Scherrer Institute, Villigen, 5232, (Switzerland)

    2015-07-01

    The critical decay constant (B/A), delayed neutron fraction (B) and generation time (A) of the Minerve reactor were measured by the Paul Scherrer Institut (PSI) and the Commissariat a l'Energie Atomique (CEA) in September 2014 using the Feynman-alpha and Power Spectral Density neutron noise measurement techniques. Three slightly subcritical configuration were measured using two 1-g {sup 235}U fission chambers. This paper reports on the results obtained by PSI in the near critical configuration (-2g). The most reliable and precise results were obtained with the Cross-Power Spectral Density technique: B = 708.4±9.2 pcm, B/A = 79.0±0.6 s{sup -1} and A 89.7±1.4 micros. Predictions of the same kinetic parameters were obtained with MCNP5-v1.6 and the JEFF-3.1 and ENDF/B-VII.1 nuclear data libraries. On average the predictions for B and B/A overestimate the experimental results by 5% and 11%, respectively. The discrepancy is suspected to come from either a corruption of the data or from the inadequacy of the point kinetic equations to interpret the measurements in the Minerve driven system. (authors)

  16. RADIATION PERFORMANCE OF GAN AND INAS/GAAS QUANTUM DOT BASED DEVICES SUBJECTED TO NEUTRON RADIATION

    Directory of Open Access Journals (Sweden)

    Dhiyauddin Ahmad Fauzi

    2017-05-01

    Full Text Available In addition to their useful optoelectronics functions, gallium nitride (GaN and quantum dots (QDs based structures are also known for their radiation hardness properties. With demands on such semiconductor material structures, it is important to investigate the differences in reliability and radiation hardness properties of these two devices. For this purpose, three sets of GaN light-emitting diode (LED and InAs/GaAs dot-in-a well (DWELL samples were irradiated with thermal neutron of fluence ranging from 3×1013 to 6×1014 neutron/cm2 in PUSPATI TRIGA research reactor. The radiation performances for each device were evaluated based on the current-voltage (I-V and capacitance-voltage (C-V electrical characterisation method. Results suggested that the GaN based sample is less susceptible to electrical changes due to the thermal neutron radiation effects compared to the QD based sample.

  17. Pionic and radiative decays of vector mesons in the chiral bag model

    International Nuclear Information System (INIS)

    Araki, M.; Osaka Univ.; Council for Scientific and Industrial Research, Pretoria; Flinders Univ. of South Australia, Bedford Park. School of Physical Sciences)

    1986-01-01

    It is shown that a mechanism, within the framework of the cloudy bag model, analogous to that for e + e - ->2γ in QED accounts qualitatively for the decays p->2π, ω->πγ and p->πγ with a bag radii 0.8-1.0 fm, and averaged momenta for decay particles. For the radiative decays, the process identical to that in the vector-dominance model gives about 60% of the total calculated width. It also explains small decay widths previously calculated, using the single quark transition process. (orig.)

  18. Introduction to neutron metrology for reactor radiation damage

    International Nuclear Information System (INIS)

    Alberman, A.; Genthon, J.P.; Wright, S.B.; Zijp, W.L.

    1977-01-01

    This document, prepared by members of the Irradiation Damage Subgroup of the Euratom Working Group on Reactor Dosimetry (EWGRD) describes the background of the procedures for determining irradiation parameters which are of interest in radiation damage experiments. The first two chapters outline the concept of damage functions and damge models. The next two chapters give information on methods to determine neutron fluences and neutron spectra. The fifth chapter gives a review of correlation data available for graphite and steels. The last chapter gives guidance how to report the relevant irradiation parameters. Attention is given to the role of the neutron spectrum in deriving values for damage fluence, energy transferred to the lattice, and number of displacements. A suggested list to report data relevant to the irradiation, the instrumentation and the testing of material is included

  19. Radiation problems expected for the German spallation neutron source

    International Nuclear Information System (INIS)

    Goebel, K.

    1981-01-01

    The German project for the construction of a Spallation Neutron Source with high proton beam power (5.5 MW) will have to cope with a number of radiation problems. The present report describes these problems and proposes solutions for keeping exposures for the staff and release of activity and radiation into the environment as low as reasonably achievable. It is shown that the strict requirements of the German radiation protection regulations can be met. The main problem will be the exposure of maintenance personnel to remanent gamma radiation, as is the case at existing proton accelerators. Closed ventilation and cooling systems will reduce the release of (mainly short-lived) activity to acceptable levels. Shielding requirements for different sections are discussed, and it is demonstrated by calculations and extrapolations from experiments that fence-post doses well below 150 mrem/y can be obtained at distances of the order of 100 metres from the principal source points. The radiation protection system proposed for the Spallation Neutron Source is discussed, in particular the needs for monitor systems and a central radiation protection data base and alarm system. (orig.)

  20. Long distance elementary measurement of the radiation dose ratio produced by neutron activation

    International Nuclear Information System (INIS)

    Zhou Changgeng; Lou Benchao; Wu Chunlei; Hu Yonghong; Li Yan

    2009-04-01

    The working principle and the structure and performances of a long distance controllable individual radiation dose ratio instrument are described. The radiation dose ratio produced by neutron activation is elementarily measured by using this instrument in the neutron generator hall with high neutron yield. When neutron yield arrives to 2 x 10 11 s -1 , the radiation dose ratio produced by neutron activation is 99.9 μSv/h in 1 h after the generator being stopped. The radiation dose ratio is reduced to 24.4 μSv/h in 39 h after the generator being stopped. When neutron yield is 3.2 x 10 10 s -1 , the radiation dose ratio produced by neutron activation is 21.9 μSv/h in 36 min, after the generator being stopped. The measurement results may provide reference for physical experimenters and neutron generator operators. (authors)

  1. Strong and radiative decays of the Ds0*(2317) and Ds1(2460)

    International Nuclear Information System (INIS)

    Cleven, Martin; Griesshammer, Harald W.; Guo, Feng-Kun; Hanhart, Christoph; Meissner, Ulf G.

    2014-01-01

    Since their discovery in 2003, the open charm states D s0 * and D s1 (2460) provide a challenge to the conventional quark model. In recent years, theoretical evidence has been accumulated for both states in favor of a predominantly DK and D * K molecular nature, respectively. However, a direct experimental proof of this hypothesis still needs to be found. Since radiative decays are generally believed to be sensitive to the inner structure of the decaying particles, we study in this work the radiative and strong decays of both the D s0 * (2317) and D s1 (2460), as well as of their counterparts in the bottom sector. While the strong decays are indeed strongly enhanced for molecular states, the radiative decays are of similar order of magnitude in different pictures. Thus, the experimental observable that allows one to conclusively quantify the molecular components of the D s0 * (2317) and D s1 (2460) is the hadronic width, and not the radiative one, in contradistinction to common belief. We also find that radiative decays of the sibling states in the bottom sector are significantly more frequent than the hadronic ones. Based on this, we identify their most promising discovery channels. (orig.)

  2. Neutron radiation characteristics of the IVth generation reactor spent fuel

    Science.gov (United States)

    Bedenko, Sergey; Shamanin, Igor; Grachev, Victor; Knyshev, Vladimir; Ukrainets, Olesya; Zorkin, Andrey

    2018-03-01

    Exploitation of nuclear power plants as well as construction of new generation reactors lead to great accumulation of spent fuel in interim storage facilities at nuclear power plants, and in spent fuel «wet» and «dry» long-term storages. Consequently, handling the fuel needs more attention. The paper is focused on the creation of an efficient computational model used for developing the procedures and regulations of spent nuclear fuel handling in nuclear fuel cycle of the new generation reactor. A Thorium High-temperature Gas-Cooled Reactor Unit (HGTRU, Russia) was used as an object for numerical research. Fuel isotopic composition of HGTRU was calculated using the verified code of the MCU-5 program. The analysis of alpha emitters and neutron radiation sources was made. The neutron yield resulting from (α,n)-reactions and at spontaneous fission was calculated. In this work it has been shown that contribution of (α,n)-neutrons is insignificant in case of such (Th,Pu)-fuel composition and HGTRU operation mode, and integral neutron yield can be approximated by the Watt spectral function. Spectral and standardized neutron distributions were achieved by approximation of the list of high-precision nuclear data. The distribution functions were prepared in group and continuous form for further use in calculations according to MNCP, MCU, and SCALE.

  3. Radiation protection aspects of a high flux, fast neutron generator

    International Nuclear Information System (INIS)

    DeLuca, P.M.; Torti, R.P.; Chenevert, G.M.; Tesmer, J.R.; Kelsey, C.A.

    1976-01-01

    During the development and operation of a gas target, DT neutron generator for use in cancer therapy, two radiation hazards were routinely encountered - personnel exposure to neutrons and to tritium. The principal hazard was irradiation by fast neutrons. By assembling the source below ground level, adding shielding and the use of a controlled access, key identification interlock, the neutron hazard has been reduced. With the present source strength of 2 x 10 12 n/sec, an average neutron dose rate in the control room of 20 mrem/hr was measured- a level compatible with a limited run schedule. The second hazard was exposure to tritium in both gaseous and solid forms. A target inventory of 90 Ci, and overall inventory of 500 Ci, and the need to modify and repair the generator present significant potential hazard due to tritium exposure. The use of protective gloves, wipe tests, urine assays, continuous room air monitoring, and equipment decontamination minimized personnel exposure and effectively confined contamination. The dose due to tritium has been ∼ 0.5 rem/year and negligible spread of contamination has occurred

  4. Neutron and photon spectrometry in mixed radiation fields

    International Nuclear Information System (INIS)

    Jancar, A.; Kopecky, Z.; Veskrna, M.

    2014-01-01

    Spectrometric measurements of the mixed fields of neutron and photon radiation in the workplaces with the L-R-0 research reactor located in the UJV Rez and with the Van de Graaff accelerator, located in the UTEF laboratories Prague, are presented in this paper. The experimental spectrometric measurements were performed using a newly developed digital measuring system, based on the technology of analog-digital converters with a very high sampling frequency (up to 2 GHz), in connection with organic scintillation detector, type BC-501A, and stilbene detector. The results of experimental measurements show high quality of spectrometry mixed fields of neutron and photon radiation across the wide dynamic range of measured energy. (authors)

  5. Radiation effects in materials for accelerator-driven neutron technologies

    International Nuclear Information System (INIS)

    Wechsler, M.S.; Lin, C.; Sommer, W.F.; Daemen, L.L.; Ferguson, P.D.

    1997-01-01

    The materials exposed to the most damaging radiation environments in an SNS (spallation neutron source) are those in the path of the incident proton beam. This includes target and window materials. These materials will experience damage from the incident protons and the spallation neutrons. The major solid targets in operating SNS's and under consideration for the 1--5 MW SNS's are W, U, and Pb. Tungsten is the target material at LANSCE, and is the project target material for an upgraded LANSCE target that is presently being designed. It is also the projected target material for the tritium producing SNS under design at LANL. In this paper, the authors present the results of spallation radiation damage calculations (displacement and He production) for tungsten

  6. Investigation of the two-photon decay following the neutron capture in hydrogen

    International Nuclear Information System (INIS)

    Wuest, N.

    1978-01-01

    The continuous two-photon radiation, resulting from thermal neutron capture in hydrogen, has been measured. This reaction can be described in second order perturbation theory and occurs besides the dominating 2223.4 keV single-photon radiation. The theoretical ratio between two-photon and one-photon process is 2.8 10 -7 for the case considered here, so coincidence experiments with extremely high sensitivity have to be performed. In order to exclude systematical errors, three measurements with a different experimental set-up have been performed. Besides the total cross section for the two-photon process, the differential cross section has been studied in one of the experiments as a function of the energy ratio of the two photons. For the branching ratio between the two- and one-photon process an upper limit of 2 x 10 -5 could be obtained. So the hypothesis that the neutron capture state and the deuterium ground state one non-orthogonal, is shown to be false. (orig.) [de

  7. β decay half-live measurement of 22 very neutron-rich isotopes in the Ti-Ni region

    International Nuclear Information System (INIS)

    Czajkowski, S.; Ameil, F.; Armbruster, P.; Donzaud, C.; Geissel, H.; Kozhuharov, C.; Schwab, W.; Bernas, M.; Dessagne, P.; Miehe, C.; Grewe, A.; Hanelt, E.; Heinz, A.; Jong, M. de; Steinhaeuser, S.; Janas, Z.

    1997-01-01

    Very neutron-rich Ti to Ni isotopes were produced in fragmentation of a 500 MeV/u 86 Kr primary beam on a Be target, separated using the Fragment Separator at GSI, and implanted in a set of PIN-diodes where β-decay particles were detected. From time-correlations analysis the unknown β-decay half-life of 22 isotopes were determined. Their values are within 10 -1 s. The β decay spectrum of 70 Co is presented as resulting from an analysis of the first β particle detected after ion implantation in the same detector. Also are presented the example of 3 β decay chains for 65 Mn and 66 Mn. The identification of such chains was instrumental in reducing the influence of background noise in the time correlation analysis while it allows life-time determinations of high confidence

  8. Global crystallographic textures obtained by neutron and synchrotron radiation

    International Nuclear Information System (INIS)

    Brokmeier, Heinz-Guenter

    2006-01-01

    Global crystallographic textures belong to the main characteristic parameters of engineering materials. The global crystallographic texture is always the average texture of a well-defined sample volume which is representative to solve practical engineering problems. Thus a beam having a high penetration power is needed available as neutron or high energetic X-ray radiation. Texture type and texture sharpness are of great importance for materials properties such as the deep drawing behaviour, one of the basic techniques in many industries. Advantages and disadvantages of both radiations make them complementary for measuring crystallographic textures in a wide range of materials

  9. Area radiation monitor at the intense pulsed-neutron source

    International Nuclear Information System (INIS)

    Eichholz, J.J.; Lynch, F.J.; Mundis, R.L.; Howe, M.L.; Dolecek, E.H.

    1981-01-01

    A tissue-equivalent ionization chamber with associated circuitry has been developed for area radiation monitoring in the Intense Pulsed-Neutron Source (IPNS) facility at Argonne National Laboratory. The conventional chamber configuration was modified in order to increase the electric field and effective volume thereby achieving higher sensitivity and linearity. The instrument provides local and remote radiation level indications and a high level alarm. Twenty-four of these instruments were fabricated for use at various locations in the experimental area of the IPNS-1 facility

  10. psi (3684) radiative decays to high-mass states

    International Nuclear Information System (INIS)

    Feldman, G.J.; Jean-Marie, B.; Sadoulet, B.; Vannucci, F.; Abrams, G.S.; Boyarski, A.M.; Breidenbach, M.; Bulos, F.; Chinowsky, W.; Friedberg, C.E.; Goldhaber, G.; Hanson, G.; Hartill, D.L.; Johnson, A.D.; Kadyk, J.A.; Larsen, R.R.; Litke, A.M.; Luke, D.; Lulu, B.A.; Luth, V.; Lynch, H.L.; Morehouse, C.C.; Paterson, J.M.; Perl, M.L.; Pierre, F.M.; Pun, T.P.; Rapidis, P.; Richter, B.; Schwitters, R.F.; Tanenbaum, W.; Trilling, G.H.; Whitaker, J.S.; Winkelmann, F.C.; Wiss, J.E.

    1975-01-01

    We present experimental evidence for the existence of the decay psi (3684) →γ,chi, chi→4π/sup plus-or-minus/, 6π/sup plus-or-minus/, π + π - K + K - , π + π - , and K + K - . There is clear evidence for at least two chi states, one at 3.41plus-or-minus0.001 GeV/c 2 and the other at 3.53plus-or-minus0.02 GeV/c 2 . The chi (3410) decays into ππ and KK and thus must have even spin and parity

  11. Neutron-decay Protons from Solar Flares as Seed Particles for CME-shock Acceleration in the Inner Heliosphere

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Ronald J. [Code 7650, Naval Research Laboratory, Washington, DC 20375 (United States); Ko, Yuan-Kuen, E-mail: ronald.murphy@nrl.navy.mil, E-mail: yuan-kuen.ko@nrl.navy.mil [Code 7680, Naval Research Laboratory, Washington, DC 20375 (United States)

    2017-09-01

    The protons in large solar energetic particle events are accelerated in the inner heliosphere by fast shocks produced by coronal mass ejections. Unless there are other sources, the protons these shocks act upon would be those of the solar wind (SW). The efficiency of the acceleration depends on the kinetic energy of the protons. For a 2000 km s{sup −1} shock, the most effective proton energies would be 30–100 keV; i.e., within the suprathermal tail component of the SW. We investigate one possible additional source of such protons: those resulting from the decay of solar-flare-produced neutrons that escape from the Sun into the low corona. The neutrons are produced by interactions of flare-accelerated ions with the solar atmosphere. We discuss the production of low-energy neutrons in flares and their decay on a interplanetary magnetic field line near the Sun. We find that even when the flaring conditions are optimal, the 30–100 keV neutron-decay proton density produced by even a very large solar flare would be only about 10% of that of the 30–100 keV SW suprathermal tail. We discuss the implication of a seed-particle source of more frequent, small flares.

  12. ${\\beta}$-decay studies of neutron-rich $^{61-70}$Mn isotopes with the new LISOL ${\\beta}$-decay setup

    CERN Multimedia

    Diriken, J V J

    2008-01-01

    The aim of this proposal is to gather new information that will serve as benchmark to test shell model calculations in the region below $^{68}$Ni, where proper residual interactions are still under development. More specifically, the ${\\beta}$-decay experiment of the $^{61-70}$Mn isotopes will highlight the development of collectivity in the Fe isotopes and its daughters. At ISOLDE, neutron-rich Mn isotopes are produced with a UC$_{x}$ target and selective laser ionization. These beams are particularly pure and reasonable yields are obtained for the neutron-rich short lived $^{61-70}$Mn isotopes. We propose to perform ${\\beta}$-decay studies on $^{61-70}$Mn utilizing the newly-developed "LISOL ${\\beta}$-decay setup", consisting of two MINIBALL cluster Ge detectors and a standard tape station. The use of digital electronics in the readout of these detectors enables us to perform a "slow correlation technique" which should indicate the possible existence of isomers in the daughter nuclei.

  13. ZZ NUCDECAYCALC, Nuclear Decay Data for Radiation Dosimetry Calculation for ICRP

    International Nuclear Information System (INIS)

    2002-01-01

    1 - Description or function: The Dosimetry Research Group (DRG) of the Health Sciences Research Division at ORNL has for several years maintained data bases of nuclear decay data for use in dosimetric calculations. The data on mean and unique energy plus intensity have been previously published, in abridged form, in Publication 38 of the International Commission on Radiological Protection (ICRP 1983). This data base was designed to address the needs in medical, environmental, and occupational radiation protection. DLC-172/NUCDECAY is required by the CCC-620/SEECAL program to calculate age-dependent specific effective energies. 2 - Methods: The unabridged data used in preparing ICRP Publication 38 are distributed in electronic form in this package. The collection consists of data on the energies and intensities of radiations emitted by the 825 radionuclides reported, although abridged, in ICRP Publication 38 plus an additional 13 radionuclides evaluated during preparation of a monograph for the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. Each collection is contained in an ASCII file (INDEXR.DAT) which is a sorted list of the radionuclides containing the decay chain information. The utility code DecayCalc extracts the decay data from the library for radionuclide(s) specified by the user. It computes the activities of radionuclides present after decay and ingrowth over a user-specified time period from 1 minute to 50 years. Decay data for any decay chain may be displayed and printed either in tabular form or graphically. DecayCalc, in a slightly modified version, will be a part of CCC-553/Rascal v3. DecayCalc is a Windows application that runs under Microsoft Windows 95 or 98, or Microsoft Windows NT 4.0 or later. The Compac Fortran 77 compiler was used to compile the code. The full source for DecayCalc is not provided but will be distributed when Rascal V3 is released

  14. Use of high voltage electron microscope to simulate radiation damage by neutrons

    International Nuclear Information System (INIS)

    Mayer, R.M.

    1976-01-01

    The use of the high voltage electron microscope to simulate radiation damage by neutrons is briefly reviewed. This information is important in explaining how alloying affects void formation during neutron irradiation

  15. Rare radiative decay of the $B_{c}$ meson

    CERN Document Server

    Barik, N; Kar, S; Dash, P C

    2001-01-01

    We study the decays B/sub c/ to D* gamma and B/sub c/ to D/sub s/* gamma in the relativistic independent quark model based on the confining potential in the scalar-vector harmonic form. Out of the two competing mechanisms contributing to these decays, we find that the weak annihilation contribution dominates the electromagnetic penguin one. Considering contributions from both mechanisms, total decay widths and branching ratios are predicted as Gamma (B/sub c/ to D* gamma )=5.22*10/sup -18/ GeV, Gamma (B/sub c/ to D/sub s/* gamma ) =1.98*10/sup -16/ GeV and Br(B/sub c/ to D* gamma ) approximately =3.64*10/sup -6/, Br(B/sub c/ to D/sub s/* gamma ) approximately =1.39*10/sup -4/ with tau /sub Bc/=0.46 ps. The decays B/sub c/ to D /sub s/* gamma can well be studied at CERN LHC in the near future. (33 refs).

  16. Calculation of Beta Decay Half-Lives and Delayed Neutron Branching Ratio of Fission Fragments with Skyrme-QRPA

    Directory of Open Access Journals (Sweden)

    Minato Futoshi

    2016-01-01

    Full Text Available Nuclear β-decay and delayed neutron (DN emission is important for the r-process nucleosynthesis after the freeze-out, and stable and safe operation of nuclear reactors. Even though radioactive beam facilities have enabled us to measure β-decay and branching ratio of neutron-rich nuclei apart from the stability line in the nuclear chart, there are still a lot of nuclei which one cannot investigate experimentally. In particular, information on DN is rather scarce than that of T1/2. To predict T1/2 and the branching ratios of DN for next JENDL decay data, we have developed a method which comprises the quasiparticle-random-phase-approximation (QRPA and the Hauser-Feshbach statistical model (HFSM. In this work, we calculate fission fragments with T1/2 ≤ 50 sec. We obtain the rms deviation from experimental half-life of 3:71. Although the result is still worse than GT2 which has been adopted in JENDL decay data, DN spectra are newly calculated. We also discuss further subjects to be done in future for improving the present approach and making next generation of JENDL decay data.

  17. Trial production of hyper-thermal neutron generator for Neutron Capture Therapy (NCT) and its radiation properties

    International Nuclear Information System (INIS)

    Sakurai, Yoshinori; Kobayashi, Toru

    1999-01-01

    In NCT, it was at first important to give a cancer portion to radiation dose required for its recovery. By finding out that whole cross-section of water comprising of a living body decreased monotonously with increase of neutron energy from about 100 barn against thermal neutron, became about 40 barn at about 0.5 eV and kept constant to 40 barn till at about 100 eV, application of thermal neutron shifted to higher temperature side, called Hyper thermal neutron, to NCT is proposed. The Hyper thermal neutron radiation can be expected to have similar controllability to that of the thermal neutron radiation. In 1977 fiscal year, a trial Hyper thermal neutron generator was produced on a base of up-to-date investigation results. As a part of property evaluation of the generator, evaluation of energy spectra in the Hyper thermal neutron generated at LINAC by TOF was conducted to confirm shift of the spectra to high temperature side. And, a Fantom experiment at KUR heavy water neutron radiation facility was also conducted to confirm effect of improvement in deep portion dose distribution. (G.K.)

  18. Activated barrier crossing dynamics in the non-radiative decay of NADH and NADPH

    Energy Technology Data Exchange (ETDEWEB)

    Blacker, Thomas S., E-mail: t.blacker@ucl.ac.uk [Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, London WC1E 6BT (United Kingdom); Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Research Department of Cell and Developmental Biology, University College London, London WC1E 6BT (United Kingdom); Marsh, Richard J., E-mail: richard.marsh@ucl.ac.uk [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Duchen, Michael R., E-mail: m.duchen@ucl.ac.uk [Research Department of Cell and Developmental Biology, University College London, London WC1E 6BT (United Kingdom); Bain, Angus J., E-mail: a.bain@ucl.ac.uk [Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, London WC1E 6BT (United Kingdom); Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)

    2013-08-30

    Highlights: ► NADH and NADPH have a high rate of non-radiative excited state decay. ► Conformational relaxation is shown to be a significant non-radiative pathway. ► The Kramers equation describes the barrier crossing dynamics of the relaxation. ► Conformational restriction upon enzyme binding will alter NAD(P)H lifetimes. - Abstract: In live tissue, alterations in metabolism induce changes in the fluorescence decay of the biological coenzyme NAD(P)H, the mechanism of which is not well understood. In this work, the fluorescence and anisotropy decay dynamics of NADH and NADPH were investigated as a function of viscosity in a range of water–glycerol solutions. The viscosity dependence of the non-radiative decay is well described by Kramers and Kramers–Hubbard models of activated barrier crossing over a wide viscosity range. Our combined lifetime and anisotropy analysis indicates common mechanisms of non-radiative relaxation in the two emitting states (conformations) of both molecules. The low frequencies associated with barrier crossing suggest that non-radiative decay is mediated by small scale motion (e.g. puckering) of the nicotinamide ring. Variations in the fluorescence lifetimes of NADH and NADPH when bound to different enzymes may therefore be attributed to differing levels of conformational restriction upon binding.

  19. Exclusive radiative and electroweak b→d and b→s penguin decays at NLO

    International Nuclear Information System (INIS)

    Beneke, M.; Seidel, D.; Feldmann, T.

    2005-01-01

    We provide standard model expectations for the rare radiative decays B→K * γ, B→ργ and B→ωγ, and the electroweak penguin decays B→K * l + l - and B→ρl + l - at the next-to-leading order (NLO), extending our previous results to b→d transitions. We consider branching fractions, isospin asymmetries and direct CPasymmetries. For the electroweak penguin decays, the lepton-invariant mass spectrum and forward-backward asymmetry is also included. Radiative and electroweak penguin transitions in b→d are mainly interesting in the search for new flavor-changing neutral current interactions, but in addition the B→ργ decays provide constraints on the CKM parameters (anti ρ, anti η). The potential impact of these constraints is discussed. (orig.)

  20. Radiative decay of coupled states in an external dc field

    International Nuclear Information System (INIS)

    Pal'chikov, V.; Sokolov, Y.; Yakovlev, V.

    2001-01-01

    This paper examines two theoretical aspects of the interference of atomic states in hydrogen which comes from the application of an external electric field F to the 2s metastable state. The radiative corrections to the Bethe-Lamb formula and anisotropy contribution to the angular distribution, which arises from interference between electric-field-induced E1-radiation and forbidden M1-radiation, are analysed

  1. Radiative decay of coupled states in an external dc field

    Energy Technology Data Exchange (ETDEWEB)

    Pal' chikov, V. [National Research Inst. for Physical-Technical and Radiotechnical Measurements (VNIIFTRI), Mendeleevo, Moscow Region (Russian Federation); Sokolov, Y. [Kurchatov Inst., Russian Research Centre, Moscow (Russian Federation); Yakovlev, V. [Moscow Engineering Physics Inst., Moscow (Russian Federation)

    2001-07-01

    This paper examines two theoretical aspects of the interference of atomic states in hydrogen which comes from the application of an external electric field F to the 2s metastable state. The radiative corrections to the Bethe-Lamb formula and anisotropy contribution to the angular distribution, which arises from interference between electric-field-induced E1-radiation and forbidden M1-radiation, are analysed.

  2. Intercomparison of radiation protection instrumentation in a pulsed neutron field

    CERN Document Server

    Caresana, M; Esposito, A; Ferrarini, M; Golnik, N; Hohmann, E; Leuschner, A; Luszik-Bhadra, M; Manessi, G; Mayer, S; Ott, K; Röhrich, J; Silari, M; Trompier, F; Volnhals, M; Wielunski, M

    2014-01-01

    In the framework of the EURADOS working group 11, an intercomparison of active neutron survey meters was performed in a pulsed neutron field (PNF). The aim of the exercise was to evaluate the performances of various neutron instruments, including commercially available rem-counters, personal dosemeters and instrument prototypes. The measurements took place at the cyclotron of the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH. The cyclotron is routinely used for proton therapy of ocular tumours, but an experimental area is also available. For the therapy the machine accelerates protons to 68 MeV. The interaction of the proton beam with a thick tungsten target produces a neutron field with energy up to about 60 MeV. One interesting feature of the cyclotron is that the beam can be delivered in bursts, with the possibility to modify in a simple and flexible way the burst length and the ion current. Through this possibility one can obtain radiation bursts of variable duration and intensity. All instru...

  3. Strong UA(1) breaking in radiative η decays

    International Nuclear Information System (INIS)

    Takizawa, M.; Nemoto, Y.; Oka, M.

    1996-08-01

    We study the η → γγ, η → γμ - μ + and η → π 0 γγ decays using an extended three-flavor Nambu-Jona-Lasinio model that includes the 't Hooft instanton induced interaction. We find that the η-meson mass, the η → γγ, η → γμ - μ + and η → π 0 γγ decay widths are in good agreement with the experimental values when the U A (1) breaking is strong and the flavor SU(3) singlet-octet mixing angle θ is about zero. The calculated ηγγ * transition form factor has somewhat weaker dependence on the squared four-momentum of the virtual photon. The effects of the U A (1) anomaly on the scalar quark contents in the nucleon, the Σ πN and Σ KN terms and the baryon number one and two systems are also studied. (author)

  4. Radiative corrections to double-Dalitz decays revisited

    Science.gov (United States)

    Kampf, Karol; Novotný, Jiři; Sanchez-Puertas, Pablo

    2018-03-01

    In this study, we revisit and complete the full next-to-leading order corrections to pseudoscalar double-Dalitz decays within the soft-photon approximation. Comparing to the previous study, we find small differences, which are nevertheless relevant for extracting information about the pseudoscalar transition form factors. Concerning the latter, these processes could offer the opportunity to test them—for the first time—in their double-virtual regime.

  5. Impurity radiation from a beam-plasma neutron source

    International Nuclear Information System (INIS)

    Molvik, A.W.

    1995-01-01

    Impurity radiation, in a worst case evaluation for a beam-plasma neutron source (BPNS), does not limit performance. Impurities originate from four sources: (a) sputtering from walls by charge exchange or alpha particle bombardment, (b) sputtering from limiters, (c) plasma desorption of gas from walls and (d) injection with neutral beams. Sources (c) and (d) are negligible; adsorbed gas on the walls of the confinement chamber and the neutral beam sources is removed by the steady state discharge. Source (b) is negligible for impinging ion energies below the sputtering threshold (T i ≤ 0.025 keV on tungsten) and for power densities to the limiter within the capabilities of water cooling (30-40 MW/m 2 ); both conditions can be satisfied in the BPNS. Source (a) radiates 0.025 MW/m 2 to the neutron irradiation samples, compared with 5 to 10 MW/m 2 of neutrons; and radiates a total of 0.08 MW from the plasma column, compared with 60 MW of injected power. The particle bombardment that yields source (a) deposits an average of 2.7 MW/m 2 on the samples, within the capabilities of helium gas cooling (10 MW/m 2 ). An additional worst case for source (d) is evaluated for present day 2 to 5 s pulsed neutral beams with 0.1% impurity density and is benchmarked against 2XIIB. The total radiation would increase a factor of 1.5 to ≤ 0.12 MW, supporting the conclusion that impurities will not have a significant impact on a BPN. (author). 61 refs, 7 figs, 2 tabs

  6. Decay of the pulsed thermal neutron flux in two-zone hydrogenous systems - Monte Carlo simulations using MCNP standard data libraries

    International Nuclear Information System (INIS)

    Wiacek, Urszula; Krynicka, Ewa

    2006-01-01

    Pulsed neutron experiments in two-zone spherical and cylindrical geometry has been simulated using the MCNP code. The systems are built of hydrogenous materials. The inner zone is filled with aqueous solutions of absorbers (H 3 BO 3 or KCl). It is surrounded by the outer zone built of Plexiglas. The system is irradiated with the pulsed thermal neutron flux and the thermal neutron decay in time is observed. Standard data libraries of the thermal neutron scattering cross-sections of hydrogen in hydrogenous substances have been used to simulate the neutron transport. The time decay constant of the fundamental mode of the thermal neutron flux determined in each simulation has been compared with the corresponding result of the real pulsed neutron experiment

  7. Measurement of the electron antineutrino angular correlation coefficient a with the neutron decay spectrometer aSPECT

    International Nuclear Information System (INIS)

    Simson, Martin

    2010-01-01

    This thesis describes measurements with the retardation spectrometer aSPECT at the Institut Laue-Langevin in Grenoble. The goal of the measurement is to determine the angular correlation coefficient a from the form of the proton recoil spectrum in the decay of the free neutron in order to determine a precise value for the ratio of the weak axial vector and vector coupling constants of the nucleon. A big improvement was achieved with the use of a silicon drift detector which was used here for the first time to detect low energetic protons. A saturation effect of the electronics that was only discovered during the analysis of the data from neutron decay proved to be not correctable. The findings from analysis, simulations and test experiments gained in this work should allow a measurement of a with high precision in a future beamtime. (orig.)

  8. Measurement of the electron antineutrino angular correlation coefficient a with the neutron decay spectrometer aSPECT

    Energy Technology Data Exchange (ETDEWEB)

    Simson, Martin

    2010-09-21

    This thesis describes measurements with the retardation spectrometer aSPECT at the Institut Laue-Langevin in Grenoble. The goal of the measurement is to determine the angular correlation coefficient a from the form of the proton recoil spectrum in the decay of the free neutron in order to determine a precise value for the ratio of the weak axial vector and vector coupling constants of the nucleon. A big improvement was achieved with the use of a silicon drift detector which was used here for the first time to detect low energetic protons. A saturation effect of the electronics that was only discovered during the analysis of the data from neutron decay proved to be not correctable. The findings from analysis, simulations and test experiments gained in this work should allow a measurement of a with high precision in a future beamtime. (orig.)

  9. Critical parameters and decay constants for one-speed neutrons in slabs and spheres with anisotropic scattering

    International Nuclear Information System (INIS)

    Yildiz, C.

    2001-01-01

    Time-dependent, one-speed neutron transport equations with strong forward and backward scattering together with isotropic scattering are studied in homogeneous slabs and spheres. First, a simple formal equivalence between the transport equations for a critical and for a time-decaying system is established. Then, the transport equation is converted into a more conventional one. The F N method of solving the resulting transport equation is applied to the calculation of the critical parameters and decay constants for the fundamental mode of the flux distribution and one-speed neutrons in spheres and infinite slabs. Numerical results are given for a number of significant figures and compared with those already available in the literature. (orig.) [de

  10. Microscopic description of the competition between spontaneous fission and α -decay in neutron-rich Ra, U and Pu nuclei

    International Nuclear Information System (INIS)

    Rodríguez-Guzmán, R; Robledo, L M

    2017-01-01

    Constrained mean-field calculations, based on the Gogny-D1M energy density functional, have been carried out to describe fission in Ra, U and Pu nuclei with neutron number 144 ≤ N ≤ 176. Fission paths, collective masses and zero-point quantum vibrational and rotational corrections are used to compute the spontaneous fission half-lives. We also pay attention to isomeric states along the considered fission paths. Alpha decay half-lives have also been computed using a parametrization of the Viola-Seaborg formula. Though there exists a strong variance of the predicted fission rates with respect to the details involved in their computation a robust trend is obtained indicating, that with increasing neutron number fission dominates over α -decay. Our results also suggest that a dynamical treatment of pairing correlations is required within the microscopic studies of the fission process in heavy nuclear systems. (paper)

  11. Rechargeable solid state neutron detector and visible radiation indicator

    Science.gov (United States)

    Stowe, Ashley C.; Wiggins, Brenden; Burger, Arnold

    2017-05-23

    A radiation detection device, including: a support structure; and a chalcopyrite crystal coupled to the support structure; wherein, when the chalcopyrite crystal is exposed to radiation, a visible spectrum of the chalcopyrite crystal changes from an initial color to a modified color. The visible spectrum of the chalcopyrite crystal is changed back from the modified color to the initial color by annealing the chalcopyrite crystal at an elevated temperature below a melting point of the chalcopyrite crystal over time. The chalcopyrite crystal is optionally a .sup.6LiInSe.sub.2 crystal. The radiation is comprised of neutrons that decrease the .sup.6Li concentration of the chalcopyrite crystal via a .sup.6Li(n,.alpha.) reaction. The initial color is yellow and the modified color is one of orange and red. The annealing temperature is between about 450 degrees C. and about 650 degrees C. and the annealing time is between about 12 hrs and about 36 hrs.

  12. Search for very light CP-odd Higgs Boson in radiative decays of Upsilon(1S).

    Science.gov (United States)

    Love, W; Savinov, V; Mendez, H; Ge, J Y; Miller, D H; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Mountain, R; Nisar, S; Randrianarivony, K; Sultana, N; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Naik, P; Rademacker, J; Asner, D M; Edwards, K W; Reed, J; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Galik, R S; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Hunt, J M; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Ledoux, J; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Mehrabyan, S; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Libby, J; Martin, L; Powell, A; Wilkinson, G; Ecklund, K M

    2008-10-10

    We search for a non-SM-like CP-odd Higgs boson (a(1)(0)) decaying to tau(+)tau(-) or mu(+)mu(-) in radiative decays of the Upsilon(1S). No significant signal is found, and upper limits on the product branching ratios are set. Our tau(+)tau(-) results are almost 2 orders of magnitude more stringent than previous upper limits. Our data provide no evidence for a Higgs state with a mass of 214 MeV decaying to mu(+)mu(-), previously proposed as an explanation for 3 Sigma(+)-->pmu(+)mu(-) events observed by the HyperCP experiment. Our results constrain NMSSM models.

  13. Radiative decays of eta-eta'-mesons in quark nonlocal model

    International Nuclear Information System (INIS)

    Efimov, G.V.; Ivanov, M.A.; Nogovitsyn, E.A.

    1980-01-01

    Leading radiative decays of eta, eta'-mesons (P→γγ, P=π 0 ,eta,eta', eta→π + π - γ, eta→π 0 γγ, eta'→Vsub(γ)(V=rho 0 , ω)) are decribed within a quark nonlocal model. Decay widths and electromagnetic form factors for the P→γl + l - decay are calculated. Calculations are performed for two mixing angles (THETA=-11 deg and THETA=-18 deg). For the case when THETA=-11 deg good agreement with experiment is achieved

  14. Radiative decays of the psi' to all-photon final states

    International Nuclear Information System (INIS)

    Lee, R.A.

    1985-05-01

    A sample of 1.8 x 10 6 produced psi's collected by the Crystal Ball detector at SPEAR is used to measure branching ratios of selected radiative psi' decays to non-charmonium states which decay into photons. A sample of 2.2 x 10 6 produced J/psi's is used to measure the same radiative decays from the J/psi. The ratios BR(psi' → γf)/BR(J/psi → γf) = 9 +- 3%, BR(psi' → γtheta)/BR(J/psi → γtheta) < 10% - 15%, BR(psi' → γeta)/BR(J/psi → γeta) < 1.8%, and BR(psi' → γeta')/BR(J/psi → γeta') < 2.6% have been obtained. (Upper limits are 90% confidence level. The upper limit for the radiative decay to the theta is uncertain due to the possible presence of an f' signal in the J/psi data). Assuming these decays proceed via the annihilation of the initial quark and antiquark to a photon and two gluons, these ratios are predicted by lowest order QCD to be the same as the ratio of leptonic branching ratios of the psi' and J/psi, or 12.0 +- 2.2%. There currently exists no compelling explanation for the discrepancy between the ratios measured for the last two decays and the theoretical expectation

  15. aCORN: An experiment to measure the electron-antineutrino correlation coefficient in free neutron decay.

    Science.gov (United States)

    Collett, B; Bateman, F; Bauder, W K; Byrne, J; Byron, W A; Chen, W; Darius, G; DeAngelis, C; Dewey, M S; Gentile, T R; Hassan, M T; Jones, G L; Komives, A; Laptev, A; Mendenhall, M P; Nico, J S; Noid, G; Park, H; Stephenson, E J; Stern, I; Stockton, K J S; Trull, C; Wietfeldt, F E; Yerozolimsky, B G

    2017-08-01

    We describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. The apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. Details of the method, apparatus, detectors, data acquisition, and data reduction scheme are presented, along with a discussion of the important systematic effects.

  16. Effect of neutron and proton radiations on magnetization of biotite

    CERN Document Server

    Abdurakhimov, A U; Sharipov, S M; Yugaj, V P; Granovskij, A B; Radkovskaya, A A

    2002-01-01

    One analyzes curves of field dependence of magnetization of biotite measured in the initial state under 4.2 K temperature subsequent to irradiation of 14 MeV energy and 1.2 x 10 sup 1 sup 3 cm sup - sup 2 dose neutrons and by 3 MeV energy and 2.2 x 10 sup 1 sup 4 cm sup - sup 2 dose protons, as well as, subsequent to annealing under 1000 deg temperature during 15 min. Irradiation by neutrons and protons was determined to result in increase of magneto-ordered phase content in biotite and, thus, in increase of magnetization of specimen. It is accounted for by formation of oxides in melt radiation thermal peaks and by freezing of high-temperature phase states corresponding to magnetite or solid solution of magnetite and hematite there. Thermal treatment does not change content of magneto-ordered phase in specimens

  17. Radiative decay following low energy charge exchange collisions at the Agrippa facility

    International Nuclear Information System (INIS)

    Bliman, S.; Dousson, S.; Hitz, D.; Mayo, M.; Bonnet, J.J.; Bordenave Montesquieu, A.; Druetta, M.

    1985-01-01

    From radiative decay observed in the X and VUV domain, it is possible to determine the (n,l) substate populations and deduce their excitation cross sections. We consider here the case of different projectiles of charge +8. For some of them, we show sigmasub(nl) for single capture from H 2 and He, as a function of energy. From the spectra it is recognized that double capture followed by radiative decay is effecitve. Observed transitions - of the same nature as dielectronic recombination satellites - are the signature of this process. Finally, in the case where energy levels are not known since the capture is a selective process, radiative decay appears thus as a means for basic spectroscopic studies. (orig.)

  18. Analysis of the radiative decay J/ψ → γωω at BESIII

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, Malte [Institut fuer Experimentalphysik I, Ruhr-Universitaet Bochum (Germany)

    2015-07-01

    Gluonic bound states like glueballs or hybrids are predicted to be copiously produced in the radiative decays of J/ψ. Especially the radiative decays into two vector mesons, J/ψ → γVV, have been intensively studied, since pseudoscalar (0{sup -}) enhancements have been observed in the ρρ, φφ and ωω final states with low statistics in the past. In this talk we show preliminary results of the analysis of the radiative decay J/ψ → γωω, using the world's largest data sample of ∼ 1.2.10{sup 9} J/ψ events collected with the Beijing Spectrometer III (BESIII) at the Beijing Electron-Positron Collider (BEPCII). The data selection, background analysis and preliminary results of a mass-independent partial wave analysis of the selected sample are presented.

  19. Neutron, Proton, and Photonuclear Cross Sections for Radiation Therapy and Radiation Protection

    International Nuclear Information System (INIS)

    Chadwick, M.B.

    1998-01-01

    The authors review recent work at Los Alamos to evaluate neutron, proton, and photonuclear cross section up to 150 MeV (to 250 MeV for protons), based on experimental data and nuclear model calculations. These data are represented in the ENDF format and can be used in computer codes to simulate radiation transport. They permit calculations of absorbed dose in the body from therapy beams, and through use of kerma coefficients allow absorbed dose to be estimated for a given neutron energy distribution. For radiation protection, these data can be used to determine shielding requirements in accelerator environments, and to calculate neutron, proton, gamma-ray, and radionuclide production. Illustrative comparisons of the evaluated cross section and kerma coefficient data with measurements are given

  20. Self-powered neutron detector

    International Nuclear Information System (INIS)

    Goldstein, N.P.; Todt, W.H.

    1976-01-01

    A self-powered neutron detector is detailed wherein a thin conductive layer of low neutron cross section, high density material is disposed about an emitter core of material which spontaneously emits radiation on neutron capture. The high density material is absorptive of beta radiation emitted by decay of the emitter core activation product, but is substantially transmissive to the high average energy prompt electrons emitted by the emitter core material. (author)

  1. Radiative decay of surface plasmons on nonspherical silver particles

    International Nuclear Information System (INIS)

    Little, J.W.; Ferrell, T.L.; Callcott, T.A.; Arakawa, E.T.

    1982-01-01

    We have studied the radiation emitted by electron-bombarded silver particles. Electron micrographs have shown that the particles, obtained by heating thin (5 nm) silver films, were oblate (flattened) with minor axes aligned along the substrate normal. The characteristic wavelength obtained by bombarding these particles with 15-keV electrons was found to vary with angle of photon emission. We have modeled this wavelength shift as a result of the mixture of radiation from dipole and quadrupole surface-plasmon oscillations on oblate spheroids. Experimental observations of the energy, polarization, and angular distribution of the emitted radiation are in good agreement with theoretical calculations

  2. Neutron Radiation Effect On 2N2222 And NTE 123 NPN Silicon Bipolar Junction Transistors

    International Nuclear Information System (INIS)

    Oo, Myo Min; Rashid, N K A Md; Hasbullah, N F; Karim, J Abdul; Zin, M R Mohamed

    2013-01-01

    This paper examines neutron radiation with PTS (Pneumatic Transfer System) effect on silicon NPN bipolar junction transistors (2N2222 and NTE 123) and analysis of the transistors in terms of electrical characterization such as current gain after neutron radiation. The key parameters are measured with Keithley 4200SCS. Experiment results show that the current gain degradation of the transistors is very sensitive to neutron radiation. The neutron radiation can cause displacement damage in the bulk layer of the transistor structure. The current degradation is believed to be governed by increasing recombination current between the base and emitter depletion region

  3. Observation of the Radiative Decay D*+→D+γ

    International Nuclear Information System (INIS)

    Bartelt, J.; Csorna, S.E.; Jain, V.; McLean, K.W.; Marka, S.; Godang, R.; Kinoshita, K.; Lai, I.C.; Pomianowski, P.; Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L.P.; Zhou, G.J.; Barish, B.; Chadha, M.; Chan, S.; Eigen, G.; Miller, J.S.; OGrady, C.; Schmidtler, M.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F.; Bliss, D.W.; Masek, G.; Paar, H.P.; Prell, S.; Sharma, V.; Asner, D.M.; Gronberg, J.; Hill, T.S.; Lange, D.J.; Morrison, R.J.; Nelson, H.N.; Nelson, T.K.; Richman, J.D.; Roberts, D.; Ryd, A.; Witherell, M.S.; Balest, R.; Behrens, B.H.; Ford, W.T.; Gritsan, A.; Park, H.; Roy, J.; Smith, J.G.; Alexander, J.P.; Bebek, C.; Berger, B.E.; Berkelman, K.; Bloom, K.; Boisvert, V.; Cassel, D.G.; Cho, H.A.; Crowcroft, D.S.; Dickson, M.; Dombrowski, S. von; Drell, P.S.; Ecklund, K.M.; Ehrlich, R.; Foland, A.D.; Gaidarev, P.; Gibbons, L.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Hopman, P.I.; Kandaswamy, J.; Kim, P.C.; Kreinick, D.L.; Lee, T.; Liu, Y.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Ogg, M.; Patterson, J.R.; Peterson, D.; Riley, D.; Soffer, A.; Valant-Spaight, B.; Ward, C.; Athanas, M.; Avery, P.; Jones, C.D.; Lohner, M.; Prescott, C.; Yelton, J.; Zheng, J.; Brandenburg, G.; Briere, R.A.; Ershov, A.; Gao, Y.S.; Kim, D.Y.; Wilson, R.

    1998-01-01

    We have observed a signal for the decay D *+ →D + γ at a significance of 4standard deviations. From the measured branching ratio B(D *+ →D + γ) /B(D *+ →D + π 0 )=0.055±0.014±0.010 we find B(D *+ →D + γ) =0.017±0.004±0.003, where the first uncertainty is statistical and the second is systematic. We also report the highest precision determination of the remaining D *+ branching fractions. copyright 1998 The American Physical Society

  4. Fast-neutron-induced potential background near the Q value of neutrinoless double-β decay of 76Ge

    Science.gov (United States)

    Tornow, W.; Bhike, Megha; Fallin, B.; Krishichayan

    2016-01-01

    The 76Ge (n,p)76Ga reaction and the subsequent β decay of 76Ga to 76Ge has been used to excite the 3951.89-keV state of 76Ge , which decays by the emission of a 2040.70-keV γ ray. Using high-purity germanium detectors, the associated pulse-height signal may be undistinguishable from the potential signal produced in neutrinoless double-β decay of 76Ge with its Q value of 2039.0 keV. At 20-MeV neutron energy the production cross section of the 2040.70-keV γ ray is approximately 0.1 mb.

  5. Formation and Decay of the Inner Electron Radiation Belt

    Science.gov (United States)

    2017-01-09

    a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 09-01-2017 2. REPORT TYPE...radiation belt: CRAND and trapped solar protons......17 APPENDIX C - Inward diffusion and loss of radiation belt protons...transfer orbit that can be damaged by the intense charged -particle environment. Protons are the prominent hazard, often causing single event upsets in

  6. Solid state detectors for neutron radiation monitoring in fusion facilities

    International Nuclear Information System (INIS)

    Gómez-Ros, J.M.

    2014-01-01

    The purpose of this communication is to summarize the main solid state based detectors proposed for neutron diagnostic in fusion applications and their applicability under the required harsh conditions in terms of intense radiation, high temperature and available space restrictions. Activation systems, semiconductor based detectors, luminescent materials and Cerenkov fibre optics sensors (C-FOS) are the main devices that are described. - Highlights: • A state-of-the-art summary of solid state based detectors are described. • Conditions and restrictions for their applicability are described. • A list of the 38 more relevant references has been included

  7. New detectors of neutron, gamma- and X-radiations

    CERN Document Server

    Lobanov, N S

    2002-01-01

    Paper presents new detectors to record absorbed doses of neutron, gamma- and X-ray radiations within 0-1500 Mrad range. DBF dosimeter is based on dibutyl phthalate. EDS dosimeter is based on epoxy (epoxide) resin, while SD 5-40 detector is based on a mixture of dibutyl phthalate and epoxy resin. Paper describes experimental techniques to calibrate and interprets the measurement results of absorbed doses for all detectors. All three detectors cover 0-30000 Mrad measured does range. The accuracy of measurements is +- 10% independent (practically) of irradiation dose rates within 20-2000 rad/s limits under 20-80 deg C temperature

  8. Foundations of radiation physics and radiation protection. 5. ed.

    International Nuclear Information System (INIS)

    Krieger, Hanno

    2017-01-01

    The following topics are dealt with: Types of radiation and radiation fields, the atomic structure, radioactive decays, decay law, natural and artificial radioactivity, interactions of ionizing photon radiation, attenuation of neutral-particle beams, interactions of neutron radiation, interactions of charged particles, ionization and energy transfer, radiation doses, radiation protection phantoms, foundations of the radiation biology of cells, effects and risks of ionizing radiation, radiation expositions of men with ionizing radiation, radiation protection law, practical radiation protection against ionizing radiations, radiation eposures in medical radiology. (HSI)

  9. Photoproduction and Radiative Decay of eta' Meson in CLAS at Jlab

    Energy Technology Data Exchange (ETDEWEB)

    Mbianda Njencheu, Georgie [Old Dominion Univ., Norfolk, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2017-05-01

    In this work the η' meson photoproduction cross sections as well as the distribution of the di-pion invariant mass, m(π+π-), in the radiative decay mode n' -> π+π-γ have been measured using the CLAS detector at the Thomas Jefferson National Accelerator Facility using tagged incident photons in the center-of-mass energy range 1.96 GeV - 2.72 GeV. The measurements are performed on a liquid hydrogen target in the reaction γ π -> π η'(η'-> π+π-γ). The analysis is based on the highest statistics collected in this decay channel in comparison to other experiments reported so far. The n' photoproduction cross sections measured with radiative decay are in a good agreement with results of previous publication from the same data set in CLAS obtained through η' -> π+π-γ decay mode. Two free parameters, α and Β, are extracted from a model-independent fit to the m(π+π-) distribution and their values are found to agree well with recent theoretical expectations. The results of both parameters confirm the existence of the box anomaly, ρ-ω mixing and effects of the a2(1320) tensor meson in the radiative decay of η'.

  10. Radiative K{sub e3} decays revisited

    Energy Technology Data Exchange (ETDEWEB)

    Gasser, J. [Universitaet Bern, Institut fuer Theoretische Physik, Bern (Switzerland); Kubis, B. [Universitaet Bern, Institut fuer Theoretische Physik, Bern (Switzerland); Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Paver, N. [Universita degli Studi di Trieste, Dipartimento di Fisica Teorica, Trieste (Italy); INFN-Trieste, Trieste (Italy); Verbeni, M. [Universidad de Granada, Departamento de Fisica Teorica y del Cosmos, Granada (Spain)

    2005-03-01

    Motivated by recent experimental results and ongoing measurements, we review the chiral perturbation theory prediction for K{sub L}{yields}{pi}{sup -+}e{sup {+-}}{nu}{sub e}{gamma} decays. Special emphasis is given to the stability of the inner bremsstrahlung-dominated relative branching ratio versus the K{sub e3} form factors, and on the separation of the structure-dependent amplitude in differential distributions over the phase space. For the structure-dependent terms, an assessment of the order p{sup 6} corrections is given, in particular, a full next-to-leading order calculation of the axial component is performed. The experimental analysis of the photon energy spectrum is discussed, and other potentially useful distributions are introduced. (orig.)

  11. Heating tokamaks by parametric decay of intense extraordinary mode radiation

    International Nuclear Information System (INIS)

    Elder, G.B.; Perkins, F.W.

    1979-08-01

    Intense electron beam technology has developed coherent, very high power (350 megawatts) microwave sources at frequencies which are a modest fraction of the electron cyclotron frequency in tokamaks. Propagation into a plasma occurs via the extraordinary mode which is subject to parametric decay instabilities in the density range ω/sub o/ 2 2 < ω/sub o/(ω/sub o/ + Ω/sub e/). For an incident wave focused onto a hot spot by a dish antenna of radius rho, the effective threshold power P/sub o/ required to induced effective parametric heating is P/sub o/ approx. = 10 MW x/rho Ω/sub e//ω/sub o/ (T/sub e//1 keV)/sup 3/2/ where x denotes the distance to the hot spot

  12. Analytic model of the radiation-dominated decay of a compact toroid

    International Nuclear Information System (INIS)

    Auerbach, S.P.

    1981-01-01

    The coaxial-gun, compact-torus experiments at LLNL and LASNL are believed to be radiation-dominated, in the sense that most or all of the input energy is lost by impurity radiation. This paper presents a simple analytic model of the radiation-dominated decay of a compact torus, and demonstrates that several striking features of the experiment (finite lifetime, linear current decay, insensitivity of the lifetime to density or stored magnetic energy) may also be explained by the hypothesis that impurity radiation dominates the energy loss. The model incorporates the essential features of the more elaborate 1 1/2-D simulations of Shumaker et al., yet is simple enough to be solved exactly. Based on the analytic results, a simple criterion is given for the maximum tolerable impurity density

  13. A review of nanostructured based radiation sensors for neutron

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Pervaiz; Mohamed, Norani Muti; Burhanudin, Zainal Arif [Center of Excellence in Nanotechnology Department of Fundamental and Applied Sciences, Department of Electrical and Electronic Engineering Universiti Teknologi PETRONAS (Malaysia)

    2012-09-26

    Currently radiation sensors with various mechanisms such as radio thermo luminescence, radiographic and radiochromic film, semiconductor and ionization have been used for the detection of nuclear radiation. Sensitivity, handling procedure, heating condition, energy response, nonlinearity, polarization, non-uniform electric field, high bias voltage and spatial resolution due to large physical size are some of the key issues faced by these sensors. Due to the excellent electrical and mechanical properties, nanostructured materials such as carbon nanotubes (CNTs) have been researched as sensing elements in the sensors to overcome the mentioned problems. However CNTs are found to pose different problems, arising from the uncontrolled helicity and small cross-sectional area. Therefore, alternative sensing elements are still been sought after and the possibility of using boron nitride nanotubes for sensing neutron is considered in this review.

  14. Neutron and/or gamma radiation detecting system

    International Nuclear Information System (INIS)

    Cerff, K.

    1985-01-01

    A large reception surface for the radiation to be detected is formed on a body of scintillation material (ZnS-AG with B matrix) which is adapted to convert neutron or gamma radiation into light energy. A large number of fiber light conductors is embedded in the body of scintillation material such that the fibers extend essentially parallel and fully across the reception surface of the body of scintillation material. The light energy, upon propagation along the fiber light conductors, is coupled into the conductors along the surface of the fibers which are unisotropic. This arrangement permits the use of unisotropic light conductor systems which provide for a separation of light collecting and light transmitting functions which results in a substantial reduction of light absorption losses during light transmission so that most of the light energy coupled into the fiber light conductors reaches the optoelectronic amplifier coupled to the end of the light conductors. (orig./HP) [de

  15. Surface erosion of fusion reactor components due to radiation blistering and neutron sputtering

    International Nuclear Information System (INIS)

    Das, S.K.; Kaminsky, M.

    1975-01-01

    Radiation blistering and neutron sputtering can lead to the surface erosion of fusion reactor components exposed to plasma radiations. Recent studies of methods to reduce the surface erosion caused by these processes are discussed

  16. Determination of the scattered radiation at the Neutron Calibration Laboratory of IPEN, SP, Brazil

    International Nuclear Information System (INIS)

    Alvarenga, Tallyson; Valeriano, Caio C.S.; Caldas, Linda V.E.; Federico, Claudio A.

    2016-01-01

    With the increased use of techniques using neutron radiation, there has been a considerable growth in the number of detectors for this kind of radiation. A neutron calibration laboratory with neutron radiation ("2"4"1AmBe) was designed. In practical situations of this type of laboratory, one of the main problems is related to the knowledge of scattered radiation. In order to evaluate this scattered radiation, simulations were carried out without the presence of structural elements and with the complete room. Fourteen measuring points were evaluated in different directions at various distances. (author)

  17. Decay, excitation, and ionization of lithium Rydberg states by blackbody radiation

    Science.gov (United States)

    Ovsiannikov, V. D.; Glukhov, I. L.

    2010-09-01

    Details of interaction between the blackbody radiation and neutral lithium atoms were studied in the temperature ranges T = 100-2000 K. The rates of thermally induced decays, excitations and ionization were calculated for S-, P- and D-series of Rydberg states in the Fues' model potential approach. The quantitative regularities for the states of the maximal rates of blackbody-radiation-induced processes were determined. Approximation formulas were proposed for analytical representation of the depopulation rates.

  18. The radiation biology of Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Coderre, J.A.

    2003-01-01

    Boron Neutron Capture Therapy (BNCT) produces a complex mixture of high and low-LET radiations in tissue. Using data on the biological effectiveness of these various dose components, derived primarily in small animals irradiated with thermal neutrons, it has been possible to express clinical BNCT doses in photon-equivalent units. The accuracy of these calculated doses in normal tissue and tumor will be reviewed. Clinical trials are underway at a number of centers. There are differences in the neutron beams at these centers, and differences in the details of the clinical protocols. Ideally, data from all centers using similar boron compounds and treatment protocols should be compared and combined, if appropriate, in a multi-institutional study in order to strengthen statistical analysis. An international dosimetry exchange is underway that will allow the physical doses from the various treatment centers to be quantitatively compared. As a first step towards the comparison of the clinical data, the normal brain tolerance data from the patients treated in the initial Brookhaven National Laboratory and the Harvard/MIT BNCT clinical trials have been compared. The data provide a good estimate of the normal brain tolerance for a somnolence syndrome endpoint, and provide guidance for setting normal brain tolerance limits in ongoing and future clinical trials. Escalation of the dose in BNCT can be accomplished by increasing the amount of the boron compound administered, increasing the duration of the neutron exposure, or both. The dose escalations that have been carried out to date at the various treatment centers will be compared and contrasted. Possible future clinical trials using BNCT in combination with other modalities will be discussed

  19. Measurement of the asymmetry parameter in the hyperon radiative decay Σ+→pγ

    International Nuclear Information System (INIS)

    Foucher, M.; Albuquerque, I.F.; Bondar, N.F.; Carrigan, R. Jr.; Chen, D.; Li Chengze; Cooper, P.S.; Denisov, A.S.; Dobrovolsky, A.V.; Dubbs, T.; Endler, A.M.F.; Escobar, C.O.; Tang Fukun; Golovtsov, V.L.; Goritchev, P.A.; Gottschalk, H.; Gouffon, P.; Grachev, V.T.; Shi Huanzhang; Yan Jie; Khanzadeev, A.V.; Kubantsev, M.A.; Kuropatkin, N.P.; Lach, J.; Luksys, M.; Lebedenko, V.N.; Dai Lisheng; Mahon, J.R.P.; McCliment, E.; Morelos, A.; Newsom, C.; Lang Pengfei; Pommot Maia, M.C.; Samsonov, V.M.; Zheng Shuchen; Smith, V.J.; Terentyev, N.K.; Timm, S.; Tkatch, I.I.; Uvarov, L.N.; Vorobyov, A.A.; Zhao Wenheng; Zhong Yuanyuan; Li Yunshan

    1992-01-01

    We have measured the asymmetry parameter (α γ ) in the hyperon radiative decay Σ + →pγ with a sample of 34 754±212 events obtained in a polarized charged hyperon beam experiment at Fermilab. We find α γ =-0.720±0.086±0.045, where the quoted errors are statistical and systematic, respectively

  20. First Experimental Study of Photon Polarization in Radiative B-s(0) Decays

    NARCIS (Netherlands)

    Aaij, R.; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Cartelle, P. Alvarez; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Archilli, F.; d'Argent, P.; Romeu, J. Arnau; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Babuschkin, I.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baker, S.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Baszczyk, M.; Batozskaya, V.; Batsukh, B.; Battista, V.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Bellee, V.; Belloli, N.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Betti, F.; Bettler, M. -O.; van Beuzekom, M.; Bezshyiko, I.; Bifani, S.; Billoir, P.; Bird, T.; Birnkraut, A.; Bitadze, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Boettcher, T.; Bondar, A.; Bondar, N.; Bonivento, W.; Borgheresi, A.; Borghi, S.; Borisyak, M.; Borsato, M.; Bossu, F.; Boubdir, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Britsch, M.; Britton, T.; Brodzicka, J.; Buchanan, E.; Burr, C.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Gomez, M. Calvo; Camboni, A.; Camboni, A.; Campana, P.; Perez, D. Campora; Perez, D. H. Campora; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Akiba, K. Carvalho; Casse, G.; Cassina, L.; Garcia, L. Castillo; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chatzikonstantinidis, G.; Chefdeville, M.; Cheung, S. -F.; Chobanova, V.; Chrzaszcz, M.; Vidal, X. Cid; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombs, G.; Coquereau, S.; Corti, G.; Corvo, M.; Sobral, C. M. Costa; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Da Cunha Marinho, F.; Dall'Occo, E.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Serio, M.; De Simone, P.; Dean, C. -T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Demmer, M.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Dordei, F.; Dorigo, M.; Suarez, A. Dosil; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dungs, K.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Deleage, N.; Easo, S.; Ebert, M.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Farley, N.; Farry, S.; Fay, R.; Fazzini, D.; Ferguson, D.; Fernandez Albor, V.; Fernandez Prieto, A.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fini, R. A.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fleuret, F.; Fohl, K.; Fontana, M.; Fontanelli, F.; Forshaw, D. C.; Forty, R.; Lima, V. Franco; Frei, C.; Furfaro, E.; Farber, C.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Garcia Martin, L. M.; Garcia Pardinas, J.; Tico, J. Garra; Garrido, L.; Garsed, P. J.; Gascon, D.; Gaspar, C.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Giani, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gizdov, K.; Gligorov, V. V.; Golubkov, D.; Golutvin, A.; Gorelov, I. V.; Gotti, C.; Gandara, M. Grabalosa; Graciani Diaz, R.; Cardoso, L. A. Granado; Grauges, E.; Graverini, E.; Graziani, G.; Grecu, A.; Griffith, P.; Grillo, L.; Cazon, B. R. Gruberg; Grunberg, O.; Gushchin, E.; Guz, Yu.; Gys, T.; Gobel, C.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; Hatch, M.; He, J.; Head, T.; Heister, A.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Hess, M.; Hicheur, A.; Hill, D.; Hombach, C.; Hopchev, H.; Hulsbergen, W.; Humair, T.; Hushchyn, M.; Hutchcroft, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jalocha, J.; Jans, E.; Jawahery, A.; Jiang, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Kariuki, J. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khairullin, E.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Koliiev, S.; Kolpin, M.; Komarov, I.; Koppenburg, P.; Kosmyntseva, A.; Kozachuk, A.; Kozeiha, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krokovny, P.; Krzemien, W.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lanfranchi, G.; Langenbruch, C.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J. -P.; Leflat, A.; Lefrancois, J.; Lefevre, R.; Lemaitre, F.; Lemos Cid, E.; Leroy, O.; Lesiak, T.; Leverington, B.; Likhomanenko, T.; Lindner, R.; Linn, C.; Lionetto, F.; Loh, D.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusiani, A.; Lyu, X.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Maltsev, T.; Manca, G.; Mancinelli, G.; Manning, P.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Marks, J.; Martellotti, G.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massacrier, L. M.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; Mcnab, A.; McNulty, R.; Meadows, B.; Meier, F.; Melnychuk, D.; Merk, M.; Merli, A.; Michielin, E.; Milanes, D. A.; Minard, M. -N.; Mitzel, D. S.; Mogini, A.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morawski, P.; Morda, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Mulder, M.; Mussini, M.; Mueller, J.; Mueller, K.; Mueller, V.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen-Mau, C.; Nieswand, S.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Oldeman, R.; Onderwater, C. J. G.; Goicochea, J. M. Otalora; Otto, A.; Owen, P.; Oyanguren, A.; Pais, P. R.; Palano, A.; Palombo, F.; Palutan, M.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Parker, W.; Parkes, C.; Passaleva, G.; Pastore, A.; Patel, G. D.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Altarelli, M. Pepe; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petrov, A.; Petruzzo, M.; Olloqui, E. Picatoste; Pietrzyk, B.; Pikies, M.; Pinci, D.; Pistone, A.; Piucci, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Pomery, G. J.; Popov, A.; Popov, D.; Popovici, B.; Poslavskii, S.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Navarro, A. Puig; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Ramos Pernas, M.; Rangel, M. S.; Raniuk, I.; Raven, G.; Redi, F.; Reichert, S.; dos Reis, A. C.; Remon Alepuz, C.; Renaudin, V.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Rodrigues, A. B.; Rodrigues, E.; Lopez, J. A. Rodriguez; Perez, P. Rodriguez; Rogozhnikov, A.; Roiser, S.; Rollings, A.; Romanovskiy, V.; Romero Vidal, A.; Ronayne, J. W.; Rotondo, M.; Ruf, T.; Ruiz Valls, P.; Saborido Silva, J. J.; Sadykhov, E.; Sagidova, N.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schellenberg, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubiger, M.; Schune, M. -H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Siddi, B. G.; Coutinho, R. Silva; Silva de Oliveira, L.; Simi, G.; Simone, S.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, I. T.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefko, P.; Stefkova, S.; Steinkamp, O.; Stemmle, S.; Stenyakin, O.; Stevenson, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Sutcliffe, W.; Swientek, K.; Syropoulos, V.; Szczekowski, M.; Szumlak, T.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Tellarini, G.; Teubert, F.; van Tilburg, J.; Tilley, M. J.; Tisserand, V.; Tobin, M.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Toriello, F.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Traill, M.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tully, A.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valassi, A.; Valat, S.; Valenti, G.; Vallier, A.; Gomez, R. Vazquez; Vazquez Regueiro, P.; Vecchi, S.; van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Venkateswaran, A.; Vernet, M.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Volkov, V.; Vollhardt, A.; Voneki, B.; Vorobyev, A.; Vorobyev, V.; Voss, C.; Vazquez Sierra, C.; Waldi, R.; Wallace, C.; Wallace, R.; Ward, D. R.; Wark, H. M.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wicht, J.; Wilkinson, G.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wraight, K.; Wright, S.; Wyllie, K.; Xie, Y.; Xing, Z.; Yang, Z.; Yu, J.; Yuan, X.; Yushchenko, O.; Zarebski, K. A.; Zavertyaev, M.; Zhelezov, A.; Zheng, Y.; Zhokhov, A.; Zhukov, V.; Zucchelli, S.

    2017-01-01

    The polarization of photons produced in radiative B-s(0) decays is studied for the first time. The data are recorded by the LHCb experiment in pp collisions corresponding to an integrated luminosity of 3 fb(-1) at center-of-mass energies of 7 and 8 TeV. A time-dependent analysis of the B-s(0) ->phi

  1. On the radiative corrections α2lnα to the positronium decay rate

    International Nuclear Information System (INIS)

    Khriplovich, I.B.; Elkhovskij, A.S.

    1990-01-01

    The radiative corrections ∼α 2 ln α to the positronium decay rate are calculated in the Breit approximation which is shown to be quite adequate for the problem. For orthopositronium the result coincides with the previous one, for parapositronium it differs from the old results. 9 refs

  2. Conservation experiments applying radiation-curable impregnating agents to intact and artifically decayed wood samples

    International Nuclear Information System (INIS)

    Schaudy, R.; Slais, E.

    1983-02-01

    Conservation experiments have been performed applying 10 selected impregnating agents to intact and chemically as well as biologically decayed wood samples. The quality of the radiation-curable impregnating agents could be valued by determination of the monomer uptake, the alteration of dimensions and volume and the deformation of the samples. The results are to be discussed. (Author) [de

  3. Radiation-induced growth and isothermal decay of infrared-stimulated luminescence from feldspar

    DEFF Research Database (Denmark)

    Guralnik, Benny; Li, Bo; Jain, Mayank

    2015-01-01

    the growth and decay of laboratory-regenerated luminescence signals. Here we review a selection of common models describing the response of infrared stimulated luminescence (IRSL) of feldspar to constant radiation and temperature as administered in the laboratory. We use this opportunity to introduce...

  4. Determination of phosphorous in cannabis by neutron activation analysis - measurement of 32P Cerenkov radiation by liquid scintillaton spectrometer

    International Nuclear Information System (INIS)

    Shinogi, M.; Mori, I.

    1977-05-01

    Thermal neutron activaton analysis with measurement of 32 P Cerenkov radiation by liquid scintillation spectrometer was used to determine phosphorus in cannabis. After irradiation of the sample, wet ashing was carried out with conc. nitric acid and 70% perchloric acid. The solution in l M perchloric acid transferred to an inorganic ion-exchange column containing acid aluminium oxide and phosphorus was quantitatively eluted with 1M hydrofluoric acid. The 32 P radioactivity of each fraction of the eluate was counted with Cerenkov radiation by a liquid scintillation spectrometer from 2 to 7 weeks after the irradiation. The activity curve decayed with 32 P half-life. The isotope channel ratio technique was applied for the quench correction. The optimal experimental conditions for chemical separation of phosphorus and for measuring the 32 P Cerenkov radiation were also examined. (Author)

  5. Radiative corrections to Higgs production from Z decay

    International Nuclear Information System (INIS)

    Kniehl, B.A.

    1992-02-01

    Full one-loop radiative corrections to the Bjorken process, Z → H fanti f, are calculated within the standard model. These corrections are used to refine the lower bound on the Higgs-boson mass coming from direct experimental searches at LEP 1 and SLC. It is demonstrated that loop effects can be reduced to a minimal level when the Born result is parametrized in terms of the Fermi constant. (orig.)

  6. Study of neutron-rich $^{51−53}$ Ca isotopes via $\\beta$-decay

    CERN Multimedia

    The high Q$_\\beta$ values in certain neutron-rich regions of the chart of nuclides opens up the possibility to study states in the daughter nuclei which lie at high excitation energy, above the neutron separation threshold. We propose to perform spectroscopy of the $\\beta$-delayed neutron emission of the $^{51-53}$K isotopes to study the population of single-particle or particle-hole states both below and above the neutron separation threshold. The VANDLE neutron detector will be used in combination with the IDS tape station setup and Ge detectors.

  7. Physical basis for prompt-neutron activation analysis

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1982-01-01

    The technique called prompt ν-ray neutron activation analysis has been applied to rapid materials analysis. The radiation following the neutron radiation capture is prompt in the sense that the nuclear decay time is on the order of 10 - 15 second, and thus the technique is not strictly activation, but should be called radiation neutron capture spectroscopy or neutron capture ν-ray spectroscopy. This paper reviews the following: sources and detectors, theory of radiative capture, nonstatistical capture, giant dipole resonance, fast neutron capture, and thermal neutron capture ν-ray spectra. 14 figures

  8. Reference neutron radiations. Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field

    International Nuclear Information System (INIS)

    2000-01-01

    ISO 8529 consists of the following parts, under the general title Reference neutron radiations: Part 1: Characteristics and methods of production; Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field; Part 3: Calibration of area and personal dosimeters and determination of response as a function of energy and angle of incidence. This Part 2. of ISO 8529 takes as its starting point the neutron sources described in ISO 8529-1. It specifies the procedures to be used for realizing the calibration conditions of radiation protection devices in neutron fields produced by these calibration sources, with particular emphasis on the corrections for extraneous effects (e.g., the neutrons scattered from the walls of the calibration room). In this part of ISO 8529, particular emphasis is placed on calibrations using radionuclide sources (clauses 4 to 6) due to their widespread application, with less details given on the use of accelerator and reactor sources (8.2 and 8.3). This part of ISO 8529 then leads to ISO 8529-3 which gives conversion coefficients and the general rules and procedures for calibration

  9. Measurement of the proton recoil spectrum in neutron beta decay with the spectrometer aSPECT. Study of systematic effects

    Energy Technology Data Exchange (ETDEWEB)

    Konrad, Gertrud Emilie

    2012-01-24

    Free neutron decay, n{yields}pe anti {nu}{sub e}, is the simplest nuclear beta decay, well described as a purely left-handed, vector minus axial-vector interaction within the framework of the Standard Model (SM) of elementary particles and fields. Due to its highly precise theoretical description, neutron beta decay data can be used to test certain extensions to the SM. Possible extensions require, e.g., new symmetry concepts like left-right symmetry, new particles, leptoquarks, supersymmetry, or the like. Precision measurements of observables in neutron beta decay address important open questions of particle physics and cosmology, and are generally complementary to direct searches for new physics beyond the SM in high-energy physics. In this doctoral thesis, a measurement of the proton recoil spectrum with the neutron decay spectrometer aSPECT is described. From the proton spectrum the antineutrinoelectron angular correlation coefficient a can be derived. In our first beam time at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz in Munich, Germany (2005-2006), background instabilities due to particle trapping and the electronic noise level of the proton detector prevented us from presenting a new value for a. In the latest beam time at the Institut Laue-Langevin (ILL) in Grenoble, France (2007-2008), the trapped particle background has been reduced sufficiently and the electronic noise problem has essentially been solved. For the first time, a silicon drift detector was used. As a result of the data analysis, we identified and fixed a problem in the detector electronics which caused a significant systematic error. The target figure of the latest beam time was a new value for a with a total relative error well below the present literature value of 4 %. A statistical accuracy of about 1.4% was reached, but we could only set upper limits on the correction of the problem in the detector electronics, which are too high to determine a meaningful result. The present

  10. Measurement of the proton recoil spectrum in neutron beta decay with the spectrometer aSPECT. Study of systematic effects

    International Nuclear Information System (INIS)

    Konrad, Gertrud Emilie

    2012-01-01

    Free neutron decay, n→pe anti ν e , is the simplest nuclear beta decay, well described as a purely left-handed, vector minus axial-vector interaction within the framework of the Standard Model (SM) of elementary particles and fields. Due to its highly precise theoretical description, neutron beta decay data can be used to test certain extensions to the SM. Possible extensions require, e.g., new symmetry concepts like left-right symmetry, new particles, leptoquarks, supersymmetry, or the like. Precision measurements of observables in neutron beta decay address important open questions of particle physics and cosmology, and are generally complementary to direct searches for new physics beyond the SM in high-energy physics. In this doctoral thesis, a measurement of the proton recoil spectrum with the neutron decay spectrometer aSPECT is described. From the proton spectrum the antineutrinoelectron angular correlation coefficient a can be derived. In our first beam time at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz in Munich, Germany (2005-2006), background instabilities due to particle trapping and the electronic noise level of the proton detector prevented us from presenting a new value for a. In the latest beam time at the Institut Laue-Langevin (ILL) in Grenoble, France (2007-2008), the trapped particle background has been reduced sufficiently and the electronic noise problem has essentially been solved. For the first time, a silicon drift detector was used. As a result of the data analysis, we identified and fixed a problem in the detector electronics which caused a significant systematic error. The target figure of the latest beam time was a new value for a with a total relative error well below the present literature value of 4 %. A statistical accuracy of about 1.4% was reached, but we could only set upper limits on the correction of the problem in the detector electronics, which are too high to determine a meaningful result. The present doctoral

  11. Utilizations of intense pulsed neutron source in radiochemistry and radiation chemistry

    International Nuclear Information System (INIS)

    Shiokawa, Takanobu; Yoshihara, Kenji; Kaji, Harumi; Kusaka, Yuzuru; Tabata, Yoneho.

    1975-01-01

    Intense pulsed neutron sources is expected to supply more useful and fundamental informations in radiochemistry and radiation chemistry. Short-lived intermediate species may be detected and the mechanisms of radiation induced reactions will be elucidated more precisely. Analytical application of pulsed neutrons is also very useful. (auth.)

  12. Weak radiative decay Λ→nγ and the radiative capture reaction K-p→Σ(1385)γ

    International Nuclear Information System (INIS)

    Larson, K.D.; Noble, A.J.; Bassalleck, B.; Burkhardt, H.; Fickinger, W.J.; Hall, J.R.; Hallin, A.L.; Hasinoff, M.D.; Horvath, D.; Jones, P.G.; Lowe, J.; McIntyre, E.K.; Measday, D.F.; Miller, J.P.; Roberts, B.L.; Robinson, D.K.; Sakitt, M.; Salomon, M.; Stanislaus, S.; Waltham, C.E.; Warner, T.M.; Whitehouse, D.A.; Wolfe, D.M.

    1993-01-01

    The branching ratio for the Λ weak radiative decay Λ→nγ has been measured. Three statistically independent results from the same experiment (Brookhaven E811) are reported here. They are combined with a previously published measurement, also from Brookhaven E811, to yield a result of (Λ→nγ)/(Λ→anything)=(1.75±0.15)x10 -3 , based on 1800 events after background subtraction. This represents a factor of 75 increase in statistics over the previous world total. A comparison with recent theoretical papers shows that no existing model provides a completely satisfactory description of all data on weak radiative decays. A search is also reported for the radiative capture process K - p→Σ(1385)γ at rest. No signal was observed and an upper limit on the branching ratio of [K - p→Σ(1385)γ]/[K - p→anything] -4 (90% C.L.) was determined

  13. Neutron-induced Backgrounds in 134Xe for Large-Scale Neutrinoless Double-Beta Decay Experiments

    Science.gov (United States)

    Moriguchi, Nina; Kidd, Mary; Tornow, Werner

    2016-09-01

    136Xe is used in large neutrinoless double-beta (0 νββ) decay experiments, such as KamLAND- Zen and EXO 200. Though highly purified, 136Xe still contains a significant amount of 134Xe. Recently, a new nuclear energy level was found in 134Xe. If 134Xe decays from this proposed excited state, it will emit a 2485.7 keV gamma ray. Because this energy lies near the region of interest of 136Xe νββ decay experiments (Q value 2457.8 keV), it could make a significant contribution to the background. A purified gaseous sample of 134Xe will be irradiated with neutrons of an incident energy of 4.0 MeV at Triangle Universities Nuclear Laboratory and monitored with high-purity germanium detectors. The spectra obtained from these detectors will be analyzed for the presence of the 2581 keV gamma ray. We will report on the status of this experiment. Future plans include expanding this measurement to higher initial neutron energies. Tennesse Tech University CISE Grant program.

  14. Block-Based Compressed Sensing for Neutron Radiation Image Using WDFB

    Directory of Open Access Journals (Sweden)

    Wei Jin

    2015-01-01

    Full Text Available An ideal compression method for neutron radiation image should have high compression ratio while keeping more details of the original image. Compressed sensing (CS, which can break through the restrictions of sampling theorem, is likely to offer an efficient compression scheme for the neutron radiation image. Combining wavelet transform with directional filter banks, a novel nonredundant multiscale geometry analysis transform named Wavelet Directional Filter Banks (WDFB is constructed and applied to represent neutron radiation image sparsely. Then, the block-based CS technique is introduced and a high performance CS scheme for neutron radiation image is proposed. By performing two-step iterative shrinkage algorithm the problem of L1 norm minimization is solved to reconstruct neutron radiation image from random measurements. The experiment results demonstrate that the scheme not only improves the quality of reconstructed image obviously but also retains more details of original image.

  15. Observation of structure in the phi phi system produced in radiative J/psi decays

    International Nuclear Information System (INIS)

    Tripsas, B.

    1988-01-01

    A sample of 4.9 million J//psi/ decays from the Mark III detector at SPEAR is used to study the radiative decay J//psi/ → γ/phi//phi/. The decay is observed in two final states; γK + K/sup /minus//K + K/sup /minus// and the previously unobserved γK + K/sup /minus//K/sub S/ 0 K/sub L/ 0 . The new final state and an improved analysis of the all charged state allow the observation of a large enhancement in the /phi//phi/ mass spectrum in the region below 2.5 GeV/c 2 in addition to the /eta//sub c/. The product branching ratio B(J//psi/ → γ/eta//sub c/) /times/ B(/eta//sub c/ → /phi//phi/) is measured in both final states. The branching ratio to the low mass region, B(J//psi/ → γ/psi//psi/, m(/psi//psi/) 2 ) is also measured. The angular distribution of the kaons is used to demonstrate that the enhancement is predominantly pseudoscalar. This effect is similar to what is observed in other radiative decays to two vector mesons and a photon. An upper limit is placed on the production of tensor glueball candidates observed to decay to /psi//psi/ by another experiment. 41 figs., 110 figs., 10 tabs

  16. Measurement of radiative decay of the resonances J/phi and phi' in tensor mesons

    International Nuclear Information System (INIS)

    Fues, W.

    1981-01-01

    At decays of the vector mesons J/psi(3100) and psi'(3685) into the final states γπ + π - and γK + K - radiative decays into the isoscalar tensor mesons f(1270) and f'(15) were looked for: J/psi → γf → γπ + π - , J/psi → γ f' → γK + K - , psi' → γf → γπ + π - , psi' → γf' → γK + K - . The measurements were performed using the double arm spectrometer DASP at the e + e - storage ring DORIS at DESY in Hamburg. The decay J/psi → γg could be observed, the measured branching ratio is GAMMA (J/psi → γf)/γ(J/psi → all) = (1.18 +- 0.28) x 10 -3 . For the other decays upper limits for the branching ratios are derived. The results are consistent with a description in the framework of quantum chromodynamics, where these radiative decays result by annihilation at the charmed quark and its antiquark into two gluons and a real photon, and the gluon system goes over into a tensor meson. In the studied mass spectra at the meson pairs from the radiative decays of J/psi and psi' no indication for a gluon bound state could be found. For the process psi' → γ 'etasub(c)(2980)' → γπ + π - or γK + K - an upper limit for the branching ratio is indicated. (HSI)

  17. Exclusive radiative decays of W and Z bosons in QCD factorization

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, Yuval [Department of Physics, LEPP, Cornell University,Ithaca, NY 14853 (United States); König, Matthias [PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics,Johannes Gutenberg University,55099 Mainz (Germany); Neubert, Matthias [Department of Physics, LEPP, Cornell University,Ithaca, NY 14853 (United States); PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics,Johannes Gutenberg University,55099 Mainz (Germany)

    2015-04-20

    We present a detailed theoretical analysis of very rare, exclusive hadronic decays of the electroweak gauge bosons V=W,Z from first principles of QCD. Our main focus is on the radiative decays V→Mγ, in which M is a pseudoscalar or vector meson. At leading order in an expansion in powers of Λ{sub QCD}/m{sub V} the decay amplitudes can be factorized into convolutions of calculable hard-scattering coefficients with the leading-twist light-cone distribution amplitude of the meson M. Power corrections to the decay rates arise first at order (Λ{sub QCD}/m{sub V}){sup 2}. They can be estimated in terms of higher-twist distribution amplitudes and are predicted to be tiny. We include one-loop O(α{sub s}) radiative corrections to the hard-scattering coefficients and perform the resummation of large logarithms (α{sub s}ln (m{sub V}{sup 2}/μ{sub 0}{sup 2})){sup n} (with μ{sub 0}∼1 GeV a typical hadronic scale) to all orders in perturbation theory. Evolution effects have an important impact both numerically and conceptually, since they reduce the sensitivity to poorly determined hadronic parameters. We present detailed numerical predictions and error estimates, which can serve as benchmarks for future precision measurements. We also present an exploratory study of the weak radiative decays Z→MW. Some of the decay modes studied here have branching ratios large enough to be accessible in the high-luminosity run of the LHC. Many of them can be measured with high accuracy at a future lepton collider. This will provide stringent tests of the QCD factorization formalism and enable novel searches for new physics.

  18. Radiative decay of the eta-, eta'-mesons in the nonlocal quark model

    International Nuclear Information System (INIS)

    Efimov, G.V.; Ivanov, M.A.; Nogovitsyn, E.A.

    1981-01-01

    P→γγ (P=π 0 , eta, eta'), eta→π + π - γ, eta→π 0 γγ, eta 1 →Vγ (V=rho 0 , ω), p→γl + l - (p=π 0 , eta, eta') radiation decays are studied for testing the applicability of the non-local quark model for description of the experimental data. The Feynman diagrams of these decays are presented, values of the widths of the Veta→γγ, eta→π + π - γ, eta→π 0 γγ, eta'→γγ, eta'→rho 0 γ, eta'→ωγ decays are calculated and given in the form of a table. Calculations are carried out for two values of the eta eta'-crossing angle: THETA=-11 deg and -18 deg. Values of invariant amplitudes of these decays are determined for π 0 →γe + e - , eta→γμ + μ - , eta'→γμ + μ - decays at THETA=-11 deg and -18 deg. The best agreement with the experimental data is noted to take place at THETA=-11 deg, the determined width of the eta→π 0 γγ decays is underestimated as compared with the experimental one [ru

  19. Radiative η' decays, the topological susceptibility and the Witten-Veneziano mass formula

    International Nuclear Information System (INIS)

    Shore, G.M.

    2000-01-01

    The formulae describing the radiative decays η ' (η)→γγ in QCD beyond the chiral limit are derived. The modifications of the conventional PCAC formulae due to the gluonic contribution to the axial anomaly in the flavour singlet channel are precisely described. The decay constants are found to satisfy a modified Dashen formula which generalises the Witten-Veneziano formula for the mass of the η'. Combining these results, it is shown how the topological susceptibility in QCD with massive, dynamical quarks may be extracted from measurements of η'(η)→γγ

  20. Radiative corrections in K{yields}{pi}l{sup +}l{sup -} decays

    Energy Technology Data Exchange (ETDEWEB)

    Kubis, Bastian; Schmidt, Rebekka [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Bonn (Germany)

    2010-11-15

    We calculate radiative corrections to the flavor-changing neutral current process K{yields}{pi}l {sup +}l{sup -}, both for charged and neutral kaon decays. While the soft-photon approximation is shown to work well for the muon channels, we discuss the necessity of further phase space cuts with electrons in the final state. It is also shown how to transfer our results to other decays such as {eta}{yields}{gamma}l{sup +} l{sup -} or {omega}{yields}{pi}{sup 0}l{sup +}l{sup -}. (orig.)

  1. Radiative open charm decay of the Y(3940), Z(3930), X(4160) resonances

    International Nuclear Information System (INIS)

    Liang, W.H.; Molina, R.; Oset, E.

    2010-01-01

    We determine the radiative decay amplitudes for the decay into D * and anti Dγ, or D * s and anti D s γ of some of the charmonium-like states classified as X, Y, Z resonances, plus some other hidden charm states which are dynamically generated from the interaction of vector mesons with charm. The mass distributions as a function of the anti Dγ or anti D s γ invariant mass show a peculiar behavior as a consequence of the D * anti D * nature of these states. The experimental search of these magnitudes can shed light on the nature of these states. (orig.)

  2. Spin tests for intermediate states in radiative psi'(3684) decay chains

    International Nuclear Information System (INIS)

    Kabir, P.K.; Hey, A.J.G.

    1976-01-01

    Analysis of the multiple angular-correlation functions for the sequential decays psi'(1 - ) → γ + chi, chi → M anti M, where M is a spinless meson, and psi'(1 - ) → γ 1 + chi, chi → γ 2 + psi, psi (1 - ) → l anti l, when the psi' is formed in e + e - collisions, shows that these can unambiguously distinguish between the spin assignments s/sub chi/ = 0, 1 or 2 for the intermediate states occurring in these decays, as well as determine the multipole amplitudes contributing to the radiative transitions. No dynamical assumptions are made beyond the conservation of angular momentum and parity; recoils are fully taken into account

  3. Asymmetry of neutrino emission from neutron beta-decay in superdense matter and strong magnetic field

    International Nuclear Information System (INIS)

    Kauts, V.L.; Savochkin, A.M.; Studenikin, A.I.

    2006-01-01

    Exact solution of Dirac equation for charged particles in homogenous magnetic field for computation of probability in presence of degenerate magnetized Fermi-gas consisting of protons, neutrons, and electrons has been used. Angular distribution of antineutrino momenta is investigated. Values of main parameters of medium is realistic for physics of neutron stars. This investigation may be applied for consideration of cooling of neutron stars [ru

  4. Search for EC-decayed neutron-deficient actinide isotopes using gas-jet coupled JAERI-ISOL

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, Kazuaki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    To study the nuclear properties of unknown neutron deficient actinide isotopes which decay mainly via orbital electron capture (EC), we have developed a composite system consisting of a gas-jet transport apparatus and a thermal ion-source at the JAERI-ISOL. With this system, search for {sup 236}Am produced in the {sup 235}U({sup 6}Li, 5n) reaction has been performed. Pu KX-rays associated with the EC decay of {sup 236}Am are observed at the mass-236 fraction. The half-life of {sup 236}Am is evaluated to be 4.4min. The outline of the gas-jet coupled JAERI-ISOL system and typical performance are given. (author)

  5. Representation of radiative strength functions within a practical model of cascade gamma decay

    Energy Technology Data Exchange (ETDEWEB)

    Vu, D. C., E-mail: vuconghnue@gmail.com; Sukhovoj, A. M., E-mail: suchovoj@nf.jinr.ru; Mitsyna, L. V., E-mail: mitsyna@nf.jinr.ru; Zeinalov, Sh., E-mail: zeinal@nf.jinr.ru [Joint Institute for Nuclear Research (Russian Federation); Jovancevic, N., E-mail: nikola.jovancevic@df.uns.ac.rs; Knezevic, D., E-mail: david.knezevic@df.uns.ac.rs; Krmar, M., E-mail: krmar@df.uns.ac.rs [University of Novi Sad, Department of Physics, Faculty of Sciences (Serbia); Dragic, A., E-mail: dragic@ipb.ac.rs [Institute of Physics Belgrade (Serbia)

    2017-03-15

    A practical model developed at the Joint Institute for Nuclear Research (JINR, Dubna) in order to describe the cascade gamma decay of neutron resonances makes it possible to determine simultaneously, from an approximation of the intensities of two-step cascades, parameters of nuclear level densities and partial widths with respect to the emission of nuclear-reaction products. The number of the phenomenological ideas used isminimized in themodel version considered in the present study. An analysis of new results confirms what was obtained earlier for the dependence of dynamics of the interaction of fermion and boson nuclear states on the nuclear shape. From the ratio of the level densities for excitations of the vibrational and quasiparticle types, it also follows that this interaction manifests itself in the region around the neutron binding energy and is probably different in nuclei that have different parities of nucleons.

  6. Representation of the radiative strength functions in the practical model of cascade gamma decay

    International Nuclear Information System (INIS)

    Vu, D.C.; Sukhovoj, A.M.; Mitsyna, L.V.; Zeinalov, Sh.; Jovancevic, N.; Knezevic, D.; Krmar, M.; Dragic, A.

    2016-01-01

    The developed in Dubna practical model of the cascade gamma decay of neutron resonance allows one, from the fitted intensities of the two-step cascades, to obtain parameters both of level density and of partial widths of emission of nuclear reaction products. In the presented variant of the model a part of phenomenological representations is minimized. Analysis of new results confirms the previous finding that dynamics of interaction between Fermi- and Bose-nuclear states depends on the form of the nucleus. It also follows from the ratios of densities of vibrational and quasi-particle levels that this interaction exists at least up to the binding neutron energy and probably differs for nuclei with varied parities of nucleons. [ru

  7. A zero-to-few-hundred eV proton beam for calibrations of neutron beta decay experiments

    CERN Document Server

    Naab, F; Zech, W; García, A; Mumm, P

    2002-01-01

    We have constructed a system using a duoplasmatron source to produce a beam of low-energy (0 - few hundred eV) protons with the principal goal of testing and calibrating detectors used to detect protons from neutron beta decay. The system is stable and produces beams by simply turning on the associated power supplies without the need of careful tuning. As an example we show data from calibration of a surface barrier detector in the emiT apparatus. Protons from the system were scattered from an Al target and used to calibrate detectors in the emiT apparatus.

  8. Theory and use of GIRAFFE for analysis of decay characteristics of delayed-neutron precursors in an LMFBR

    International Nuclear Information System (INIS)

    Gross, K.C.

    1980-07-01

    The application of the computer code GIRAFFE (General Isotope Release Analysis For Failed Elements) written in FORTRAN IV is described. GIRAFFE was designed to provide parameter estimates of the nonlinear discrete-measurement models that govern the transport and decay of delayed-neutron precursors in a liquid-metal fast breeder reactor (LMFBR). The code has been organized into a set of small, relatively independent and well-defined modules to facilitate modification and maintenance. The program logic, the numerical techniques, and the methods of solution used by the code are presented, and the functions of the MAIN program and of each subroutine are discussed

  9. The ration/gsub(A)/gsub(V) derived from the proton spectrum in free-neutron decay

    International Nuclear Information System (INIS)

    Stratowa, Ch.; Dobrozemsky, R.; Weinzierl, P.

    1978-08-01

    The electron-neutrino angular correlation coefficient was determined by measuring the shape of the proton recoil spectrum from free-neutron decay. The protons leaving a highly evacuated tangential reactor beam tube were analysed by a spherical condenser spectrometer and counted in an ion-electron converter detector. The design of the apparatus, the possible disturbing influences and the measures to reduce their effects are discussed. The remaining corrections were either calculated or determined by auxiliary measurements and applied to the spectral shape. The sources of systematic errors are considered and included in the final results. We obtained a- is equal to -0.1017+-0.0051 giving

  10. 'aspect' - a new spectrometer for the measurement of the angular correlation coefficient a in neutron beta decay

    CERN Document Server

    Zimmer, O; Grinten, M G D; Heil, W; Glück, F

    2000-01-01

    The combination of the coefficient a of the antineutrino/electron angular correlation with the beta asymmetry of the neutron provides a sensitive test for scalar and tensor contributions to the electroweak Lagrangian, as well as for right-handed currents. A method is given for measuring a with high sensitivity from the proton recoil spectrum. The method is based on a magnetic spectrometer with electrostatic retardation potentials such as used for searches of the neutrino mass in tritium beta decay. The spectrometer can also be used for similar studies using radioactive nuclei.

  11. A practical proposal for neutron dosimetry in radiation protection

    International Nuclear Information System (INIS)

    Busuoli, G.; Pelliccioni, M.

    1985-01-01

    The innovations recommended in ICRP Publication 26 give rise to questionable consequences for current radiation protection practice. One of the most efficient is a proliferation of quantities for external exposure, the so called ''operational quantities'', devoid of any physical basis and scientifically undesirable. This risks undermining the unitary order given to the formulation of the limits. Moreover, as soon as an agreement is reached, then most of the instrumentation used at present should be replaced or modified. In the case of neutron dosimetry, at the moment, changes would be inappropriate. This is because one must take into account the results from the reassessment of the doses received by Japanese who were exposed at Hiroshima and Nagasaki, and the recent rumours about an increase of the quality factor at low doses. While awaiting further reflection on the matter, the way to continue to use the most popular neutron environmental instrument, the rem-counter is explained. The proposed solution, which is as open to question as any other, should at least allow considerable economical advantages and secure the continuity of current practice. (author)

  12. Analysis of average radiation widths of neutron resonances

    International Nuclear Information System (INIS)

    Malezki, H.; Popov, A.B.; Trzeciak, K.

    1982-01-01

    On the basis of the available data on parameters of neutron resonances average values of radiation widths (GITAsub(γ)) are calculated for a wide range of nuclei in the 50 upto 250 atomic weight range. Experimental values are compared with different variants of theoretical estimates of GITAsub(γ) which are reduced to the GITAsub(γ) dependence upon atomic weight A, excitation energy U and level density parameter a as GITAsub(γ)=CAsup(α)Usup(β)asup(γ). Besides, empirical values C, α, β, γ are selected satisfying the experimental data best of all. It is determined that the use of a=kA hypothesis leads to a sufficiently better agreement between all theoretical estimates of GITAsub(γ) and experimental values. It turned out that the estimations by Weisskopf, Bondarenko-Urin or with empirically chosen parameters give an approximately similar correspondence of calculated values GITAsub(γ)sup(p) to experimental data [ru

  13. Strong γ-ray emission from neutron unbound states populated in β-decay: Impact on (n,γ) cross-section estimates

    International Nuclear Information System (INIS)

    Tain, J. L.; Guadilla, V.; Valencia, E.; Algora, A.

    2017-01-01

    Total absorption gamma-ray spectroscopy is used to measure accurately the intensity of γ emission from neutron-unbound states populated in the β-decay of delayed-neutron emitters. From the comparison of this intensity with the intensity of neutron emission one can deduce information on the (n,γ) cross section for unstable neutron-rich nuclei of interest in r process abundance calculations. A surprisingly large γ branching was observed for a number of isotopes. Here, the results are compared with Hauser-Feshbach calculations and discussed.

  14. Experimental validation of GADRAS's coupled neutron-photon inverse radiation transport solver

    International Nuclear Information System (INIS)

    Mattingly, John K.; Mitchell, Dean James; Harding, Lee T.

    2010-01-01

    Sandia National Laboratories has developed an inverse radiation transport solver that applies nonlinear regression to coupled neutron-photon deterministic transport models. The inverse solver uses nonlinear regression to fit a radiation transport model to gamma spectrometry and neutron multiplicity counting measurements. The subject of this paper is the experimental validation of that solver. This paper describes a series of experiments conducted with a 4.5 kg sphere of α-phase, weapons-grade plutonium. The source was measured bare and reflected by high-density polyethylene (HDPE) spherical shells with total thicknesses between 1.27 and 15.24 cm. Neutron and photon emissions from the source were measured using three instruments: a gross neutron counter, a portable neutron multiplicity counter, and a high-resolution gamma spectrometer. These measurements were used as input to the inverse radiation transport solver to evaluate the solver's ability to correctly infer the configuration of the source from its measured radiation signatures.

  15. Interference between radiative emission and autoionization in the decay of excited states of atoms

    International Nuclear Information System (INIS)

    Armstrong, L. Jr.; Theodosiou, C.E.; Wall, M.J.

    1978-01-01

    An excited state of an atom which can autoionize can also undergo radiative decay. We consider the interaction between the final states resulting from these two modes of decay, and its effects on such quantities as the fluorescence yield of the excited state, excitation profile of the excited state, and the spectra of the emitted photons and electrons. It is shown that the fraction of decays of the excited state resulting in a photon (fluorescence yield) is particularly sensitive to the details of the final-state interaction. In lowest order in the final-state interaction, the fluorescence yield is increased by a factor (1 + 1/q 2 ) from the traditional value, where q is the Fano q parameter relating to the excited state and the final atomic state

  16. Calculations of radiation damage in target, container and window materials for spallation neutron sources

    International Nuclear Information System (INIS)

    Wechsler, M.S.; Mansur, L.K.

    1996-01-01

    Radiation damage in target, container, and window materials for spallation neutron sources is am important factor in the design of target stations for accelerator-driver transmutation technologies. Calculations are described that use the LAHET and SPECTER codes to obtain displacement and helium production rates in tungsten, 316 stainless steel, and Inconel 718, which are major target, container, and window materials, respectively. Results are compared for the three materials, based on neutron spectra for NSNS and ATW spallation neutron sources, where the neutron fluxes are normalized to give the same flux of neutrons of all energies

  17. An estimate of the radiation-induced cancer risk from the whole-body stray radiation exposure in neutron radiotherapy

    International Nuclear Information System (INIS)

    Geraci, J.P.; Jackson, K.L.; Mariano, M.S.

    1982-01-01

    1980 BEIR III risk factors have been used to estimate the secondary cancer risks from the whole-body stray radiation exposures occurring in neutron radiotherapy. Risks were calculated using linear, linear-quadratic and quadratic dose-response models for the gamma component of the stray radiation. The linear dose-response model was used to calculate risk for the neutron component of the stray radiation. These estimates take into consideration for the first time the age and sex distribution of patients undergoing neutron therapy. Changes in risk as a function of the RBE (10-100) assigned to the stray neutron radiation component have also been assessed. Excess risks in neutron-treated patients have been compared with excess risks for photon-treated patients and with the expected incidence of cancer in a normal population having the same age and sex distribution. Results indicate that it will be necessary to tolerate a higher incidence of secondary cancers in patients undergoing fast neutron therapy than is the case with conventional photon therapy. For neutron RBEs of less than 50 the increased risk is only a fraction of the normal expected incidence of cancer in this population. Comparison of the radiation-induced risk with reported normal tissue complication rates in the treatment volume indicates that the excess cancer risk is substantially lower than the risk from other late normal tissue effects. (author)

  18. EDISTR: a computer program to obtain a nuclear decay data base for radiation dosimetry

    International Nuclear Information System (INIS)

    Dillman, L.T.

    1980-01-01

    This report provides documentation for the computer program EDISTR. EDISTR uses basic radioactive decay data from the Evaluated Nuclear Structure Data File developed and maintained by the Nuclear Data Project at the Oak Ridge National Laboratory as input, and calculates the mean energies and absolute intensities of all principal radiations associated with the radioactive decay of a nuclide. The program is intended to provide a physical data base for internal dosimetry calculations. The principal calculations performed by EDISTR are the determination of (1) the average energy of beta particles in a beta transition, (2) the beta spectrum as function of energy, (3) the energies and intensities of x-rays and Auger electrons generated by radioactive decay processes, (4) the bremsstrahlung spectra accompanying beta decay and monoenergetic Auger and internal conversion electrons, and (5) the radiations accompanying spontaneous fission. This report discusses the theoretical and empirical methods used in EDISTR and also practical aspects of the computer implementation of the theory. Detailed instructions for preparing input data for the computer program are included, along with examples and discussion of the output data generated by EDISTR

  19. Simulation of decay processes and radiation transport times in radioactivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    García-Toraño, E., E-mail: e.garciatorano@ciemat.es [Laboratorio de Metrología de Radiaciones Ionizantes, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Peyres, V. [Laboratorio de Metrología de Radiaciones Ionizantes, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Bé, M.-M.; Dulieu, C.; Lépy, M.-C. [CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB), Bldg 602, PC111, 91191 Gif-sur-Yvette Cedex (France); Salvat, F. [Facultat de Física (FQA and ICC), Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain)

    2017-04-01

    The Fortran subroutine package PENNUC, which simulates random decay pathways of radioactive nuclides, is described. The decay scheme of the active nuclide is obtained from the NUCLEIDE database, whose web application has been complemented with the option of exporting nuclear decay data (possible nuclear transitions, branching ratios, type and energy of emitted particles) in a format that is readable by the simulation subroutines. In the case of beta emitters, the initial energy of the electron or positron is sampled from the theoretical Fermi spectrum. De-excitation of the atomic electron cloud following electron capture and internal conversion is described using transition probabilities from the LLNL Evaluated Atomic Data Library and empirical or calculated energies of released X rays and Auger electrons. The time evolution of radiation showers is determined by considering the lifetimes of nuclear and atomic levels, as well as radiation propagation times. Although PENNUC is designed to operate independently, here it is used in conjunction with the electron-photon transport code PENELOPE, and both together allow the simulation of experiments with radioactive sources in complex material structures consisting of homogeneous bodies limited by quadric surfaces. The reliability of these simulation tools is demonstrated through comparisons of simulated and measured energy spectra from radionuclides with complex multi-gamma spectra, nuclides with metastable levels in their decay pathways, nuclides with two daughters, and beta plus emitters.

  20. Radioactive Decay

    Science.gov (United States)

    Radioactive decay is the emission of energy in the form of ionizing radiation. Example decay chains illustrate how radioactive atoms can go through many transformations as they become stable and no longer radioactive.

  1. The radiative decays $B \\to V_{\\gamma}$ at next-to-leading order in QCD

    CERN Document Server

    Bosch, S W; Bosch, Stefan W.; Buchalla, Gerhard

    2002-01-01

    We provide a model-independent framework for the analysis of the radiative B-meson decays B -> K* gamma and B -> rho gamma. In particular, we give a systematic discussion of the various contributions to these exclusive processes based on the heavy-quark limit of QCD. We propose a novel factorization formula for the consistent treatment of B -> V gamma matrix elements involving charm (or up-quark) loops, which contribute at leading power in Lambda_QCD/m_B to the decay amplitude. Annihilation topologies are shown to be power suppressed. In some cases they are nevertheless calculable. The approach is similar to the framework of QCD factorization that has recently been formulated for two-body non-leptonic B decays. These results allow us, for the first time, to compute exclusive b -> s(d) gamma decays systematically beyond the leading logarithmic approximation. We present results for these decays complete to next-to-leading order in QCD and to leading order in the heavy-quark limit. Phenomenological implications ...

  2. Order-α radiative corrections for semileptonic decays of polarized baryons

    International Nuclear Information System (INIS)

    Glueck, F.; Toth, K.

    1992-01-01

    Model independent radiative corrections are calculated for the Σ - → neν-bar, Λ → neν-bar and n → peν-bar decays with polarized initial baryons. The method of polarization asymmetry calculations is outlined, and the most important formulae are presented. Numerical results for the corrections to two- and one-dimensional asymmetry distributions and totally integrated asymmetries are tabulated for the electron, neutrino, hadron, α and β asymmetries. (author) 73 refs.; 5 tabs

  3. Decay of giant resonances states in radiative pion capture by 1p shell nuclei

    International Nuclear Information System (INIS)

    Dogotar, G.E.

    1978-01-01

    The decay of the giant resonance states excited in tthe radiative pion capture on the 9 Be, 11 B, 13 C and 14 N nuclei is considered in the shell model with intermediate coupling. It is shown that the excited states in the daughter nuclei (A-1, Z-1) are mainly populated by intermediate states with spin by two units larger than the spin of the target nuclei. Selected coincidence experiments are proposed

  4. Search for Dimuon Decays of a Light Scalar Boson in Radiative Transitions Upsilon ->gamma A(0)

    NARCIS (Netherlands)

    Aubert, B.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D. N.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Osipenkov, I. L.; Petigura, E.; Tackmann, K.; Tanabe, T.; Hawkes, C. M.; Soni, N.; Watson, A. T.; Schroeder, T.; Asgeirsson, D. J.; Fulsom, B. G.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; Barrett, M.; Khan, A.; Randle-Conde, A.; Blinov, V. E.; Bukin, A. D.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Bondioli, M.; Curry, S.; Eschrich, I.; Kirkby, D.; Lankford, A. J.; Lund, P.; Mandelkern, M.; Martin, E. C.; Stoker, D. P.; Atmacan, H.; Gary, J. W.; Liu, F.; Long, O.; Vitug, G. M.; Yasin, Z.; Sharma, V.; Campagnari, C.; Hong, T. M.; Kovalskyi, D.; Mazur, M. A.; Richman, J. D.; Beck, T. W.; Eisner, A. M.; Heusch, C. A.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Schalk, T.; Schumm, B. A.; Seiden, A.; Winstrom, L. O.; Doll, D. A.; Echenard, B.; Fang, F.; Hitlin, D. G.; Narsky, I.; Ongmongkolku, P.; Piatenko, T.; Andreassen, R.; Mancinelli, G.; Meadows, B. T.; Mishra, K.; Sokoloff, M. D.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Hirschauer, J. F.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Wilson, J. R.; Feltresi, E.; Hauke, A.; Jasper, H.; Karbach, T. M.; Merkel, J.; Petzold, A.; Spaan, B.; Wacker, K.; Kobel, M. J.; Nogowski, R.; Schubert, K. R.; Schwierz, R.; Volk, A.; Bernard, D.; Latour, E.; Verderi, M.; Clark, P. J.; Playfer, S.; Watson, J. E.; Andreotti, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cecchi, A.; Cibinetto, G.; Fioravanti, E.; Franchini, P.; Luppi, E.; Munerato, M.; Negrini, M.; Petrella, A.; Piemontese, L.; Santoro, V.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Pacetti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Tosi, S.; Chaisanguanthum, K. S.; Morii, M.; Adametz, A.; Marks, J.; Schenk, S.; Uwer, U.; Bernlochner, F. U.; Klose, V.; Lacker, H. M.; Bard, D. J.; Dauncey, P. D.; Tibbetts, M.; Behera, P. K.; Charles, M. J.; Mallik, U.; Cochran, J.; Crawley, H. B.; Dong, L.; Eyges, V.; Meyer, W. T.; Prell, S.; Rosenberg, E. I.; Rubin, A. E.; Gao, Y. Y.; Gritsan, A. V.; Guo, Z. J.; Arnaud, N.; Bequilleux, J.; D'Orazio, A.; Davier, M.; Derkach, D.; Grosdidier, G.; Le Diberder, F.; Lepeltier, V.; Lutz, A. M.; Malaescu, B.; Pruvot, S.; Roudeau, P.; Schune, M. H.; Serrano, J.; Sordini, V.; Stocchi, A.; Wormser, G.; Lange, D. J.; Wright, D. M.; Bingham, I.; Burke, J. P.; Chavez, C. A.; Fry, J. R.; Gabathuler, E.; Gamet, R.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Clarke, C. K.; Di Lodovico, F.; Sacco, R.; Sigamani, M.; Cowan, G.; Paramesvaran, S.; Wren, A. C.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Hafner, A.; Alwyn, K. E.; Barlow, R. J.; Jackson, G.; Lafferty, G. D.; Yi, J. I.; Anderson, J.; Jawahery, A.; Roberts, D. A.; Simi, G.; Tuggle, J. M.; Dallapiccola, C.; Salvati, E.; Cowan, R.; Dujmic, D.; Fisher, P. H.; Henderson, S. W.; Sciolla, G.; Spitznagel, M.; Yamamoto, R. K.; Zhao, M.; Patel, P. M.; Robertson, S. H.; Schram, M.; Biassoni, P.; Lazzaro, A.; Lombardo, V.; Palombo, F.; Stracka, S.; Bauer, J. M.; Cremaldi, L.; Godang, R.; Kroeger, R.; Sonnek, P.; Summers, D. J.; Simard, M.; Taras, P.; Nicholson, H.; De Nardo, G.; Lista, L.; Monorchio, D.; Onorato, G.; Sciacca, C.; Raven, G.; Snoek, H. L.; Jessop, C. P.; Knoepfel, K. J.; LoSecco, J. M.; Corwin, L. A.; Honscheid, K.; Kagan, H.; Kass, R.; Morris, J. P.; Rahimi, A. M.; Regensburger, J. J.; Sekula, S. J.; Wong, Q. K.; Blount, N. L.; Brau, J.; Frey, R.; Igonkina, O.; Kolb, J. A.; Lu, M.; Rahmat, R.; Sinev, N. B.; Strom, D.; Strube, J.; Torrence, E.; Castelli, G.; Gagliardi, N.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simonetto, F.; Stroili, R.; Voci, C.; del Amo Sanchez, P.; Ben-Haim, E.; Bonneaud, G. R.; Briand, H.; Chauveau, J.; Hamon, O.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Perez, A.; Prendki, J.; Sitt, S.; Gladney, L.; Biasini, M.; Manoni, E.; Angelini, C.; Batignani, G.; Bettarini, S.; Calderini, G.; Carpinelli, M.; Cervelli, A.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Morganti, M.; Neri, N.; Paoloni, E.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Lu, C.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Anulli, F.; Baracchini, E.; Cavoto, G.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Jackson, P. D.; Gioi, L. Li; Mazzoni, M. A.; Morganti, S.; Piredda, G.; Renga, F.; Voena, C.; Ebert, M.; Schroeder, H.; Waldi, R.; Adye, T.; Franek, B.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Esteve, L.; de Monchenault, G. Hamel; Kozanecki, W.; Vasseur, G.; Yeche, Ch.; Zito, M.; Allen, M. T.; Aston, D.; Bartoldus, R.; Benitez, J. F.; Cenci, R.; Coleman, J. P.; Convery, M. R.; Dingfelder, J. C.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Field, R. C.; Franco Sevilla, M.; Gabareen, A. M.; Graham, M. T.; Grenier, P.; Hast, C.; Innes, W. R.; Kaminski, J.; Kelsey, M. H.; Kim, H.; Kim, P.; Kocian, M. L.; Leith, D. W. G. S.; Lindquist, B.; Luitz, S.; Luth, V.; Lynch, H. L.; MacFarlane, D. B.; Marsiske, H.; Messner, R.; Muller, D. R.; Neal, H.; Nelson, S.; O'Grady, C. P.; Ofte, I.; Perl, M.; Ratcliff, B. N.; Roodman, A.; Salnikov, A. A.; Schindler, R. H.; Schwiening, J.; Snyder, A.; Su, D.; Sullivan, M. K.; Suzuki, K.; Swain, S. K.; Thompson, J. M.; Va'vra, J.; West, C. A.; Wisniewski, W. J.; Wittgen, M.; Wright, D. H.; Wulsin, H. W.; Yarritu, A. K.; Young, C. C.; Ziegler, V.; Park, W.; Purohit, M. V.; White, R. M.; Wilson, J. R.; Burchat, P. R.; Edwards, A. J.; Miyashita, T. S.; Ahmed, S.; Alam, M. S.; Ernst, J. A.; Pan, B.; Saeed, M. A.; Zain, S. B.; Soffer, A.; Spanier, S. M.; Wogsland, B. J.; Eckmann, R.; Ritchie, J. L.; Ruland, A. M.; Schilling, C. J.; Schwitters, R. F.; Wray, B. C.; Drummond, B. W.; Izen, J. M.; Lou, X. C.; Bianchi, F.; Gamba, D.; Pelliccioni, M.; Bomben, M.; Bosisio, L.; Cartaro, C.; Della Ricca, G.; Lanceri, L.; Vitale, L.; Azzolini, V.; Lopez-March, N.; Martinez-Vidal, F.; Milanes, D. A.; Oyanguren, A.; Albert, J.; Banerjee, Sw.; Bhuyan, B.; Choi, H. H. F.; Hamano, K.; Kowalewski, R.; Lewczuk, M. J.; Nugent, I. M.; Roney, J. M.; Sobie, R. J.; Gershon, T. J.; Harrison, P. F.; Ilic, J.; Latham, T. E.; Mohanty, G. B.; Puccio, E. M. T.; Band, H. R.; Dasu, S.; Flood, K. T.; Pan, Y.; Prepost, R.; Vuosalo, C. O.

    2009-01-01

    We search for evidence of a light scalar boson in the radiative decays of the Υ(2S) and Υ(3S) resonances: Υ(2S,3S)→γA0, A0→μ+μ−. Such a particle appears in extensions of the standard model, where a light CP-odd Higgs boson naturally couples strongly to b quarks. We find no evidence for such

  5. Relative radiative decay rates of vacancies in L-subshells of heavy elements

    International Nuclear Information System (INIS)

    Barros Leite, C.V. de; Pinho, A.G. de; Castro Faria, N.V. de.

    1977-01-01

    Relative radiative decay of vacancies in L-subshells were measured for a large number of heavy elements with a Si(Li) detection system. A graphical method was employed to analyze the x-ray spectra so obtained. Systematic results are presented together with other already published results obtained in our laboratories in recent years. This covers the interval 74<=Z<=93. Results are compared with theoretical predictions and experimental data from other authors and some general features are noted

  6. Monte-Carlo study on primary knock-on atom energy spectrum produced by neutron radiation

    International Nuclear Information System (INIS)

    Zhou Wei; Liu Yongkang; Deng Yongjun; Ma Jimin

    2012-01-01

    Computational method on energy distribution of primary knock-on atom (PKA) produced by neutron radiation was built in the paper. Based on the DBCN card in MCNP, reaction position, reaction type and energy transfer between neutrons and atoms were recorded. According to statistic of these data, energy and space distributions of PKAs were obtained. The method resolves preferably randomicity of random number and efficiency of random sampling computation. The results show small statistical fluctuation and well statistical. Three-dimensional figure of energy and space distribution of PKAs were obtained, which would be important to evaluate radiation capability of materials and study radiation damage by neutrons. (authors)

  7. The ρ radiative decay width: A measurement at 200 GeV

    International Nuclear Information System (INIS)

    Capraro, L.; Levy, P.; Querrou, M.; Hecke, B. van; Verbeken, M.; Amendolia, S.R.; Batignani, G.; Bedeschi, A.; Bellamy, E.H.; Bertolucci, E.; Bosisio, L.; Bottigli, U.; Bradaschia, C.; Fidecaro, F.; Foa, L.; Focardi, E.; Giannetti, P.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Ristori, L.; Scribano, A.; Stefanini, A.; Tonelli, G.; Beck, G.A.; Bologna, G.; D'Ettorre Piazzoli, B.; Mannocchi, G.; Picchi, P.; Istituto Nazionale di Fisica Nucleare, Frascati; Budinich, M.; Liello, F.; Paver, N.; Rolandi, L.; Green, M.G.; March, P.V.; Landon, M.P.J.; Strong, J.A.; Tenchini, R.

    1987-01-01

    The ρ - radiative decay width has been measured by studying the production of ρ - via the Primakoff effect by 200 GeV incident π - on Cu and Pb targets. This width was obtained by fitting the measured dσ/dt for ρ production with the theoretical coherent differential cross section including both the electromagnetic and strong contributions. The measured radiative width value is 81±4±4 keV: it is consistent with the ratio Γ(ρ → πγ)/Γ(ω → πγ) ∝ 1/9 as expected from the vector dominance and the quark model. (orig.)

  8. Decay and acceptability of mangos treated with combinations of hot water, imazalil, and gamma radiation

    International Nuclear Information System (INIS)

    Spalding, D.H.; Reeder, W.F.

    1986-01-01

    Combination treatments with radiation at 200 or 750 Gy and hot water (53 C) or hot 0.1% a.i. imazalil (53 C) for 3 min were more effective than single treatments for control of anthracnose and stem-end rot of Tommy Atkins mangos caused by Colletotrichum gloeosporioides and Diplodia natalensis or Phomopsis citri, respectively. Irradiation at 750 Gy inhibited development of ripe skin color and caused some browning and pitting of the skin. Effects of radiation on skin color and injury were partially offset when heat treatment preceded irradiation. Individual wrapping of mangos in shrink film resulted in increased decay and breakdown. (author)

  9. Decay and acceptability of mangos treated with combinations of hot water, imazalil, and gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Spalding, D. H.; Reeder, W. F.

    1986-12-15

    Combination treatments with radiation at 200 or 750 Gy and hot water (53 C) or hot 0.1% a.i. imazalil (53 C) for 3 min were more effective than single treatments for control of anthracnose and stem-end rot of Tommy Atkins mangos caused by Colletotrichum gloeosporioides and Diplodia natalensis or Phomopsis citri, respectively. Irradiation at 750 Gy inhibited development of ripe skin color and caused some browning and pitting of the skin. Effects of radiation on skin color and injury were partially offset when heat treatment preceded irradiation. Individual wrapping of mangos in shrink film resulted in increased decay and breakdown. (author)

  10. Characterization of plastic scintillators for detection of radioactivity: Light yield, Time decay measurements and Neutron/γ Pulse Shape Discrimination

    International Nuclear Information System (INIS)

    Montbarbon, E.; Pansu, R.B.; Hamel, M.; Coulon, R.

    2015-07-01

    Since Helium-3 shortage, organic scintillators play a major role in neutron detection. CEA LIST decided to focus on plastic scintillators. By definition, a plastic scintillator is a radio-luminescent polymer; this means that it emits light after interaction with an ionizing radiation. A platform was developed to characterize lab-made prepared scintillators and to compare them with commercial scintillators. Three physicochemical criteria are determined with this unique platform. (authors)

  11. Synergistic interaction between the neutron and gamma radiation on LACA mice hemopoietic stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H

    1982-02-01

    Based on the radiation action dual theory of DNA single and double strand breaks, a hypothetical RBE mathematical model for the effect of the mixed radiation of neutron and gamma rays on LACA mice hemopoietic stem cells was formulated. In comparison of the RBE values of different ratio of neutron and gamma-ray mixed radiation with their theoretical additive RBE values, the preliminary impression is that the mixed radiation is more effective than that of the theoretical additive effect. It seems that the existence of synergist in the mixed radiation might be valid.

  12. Decay of new mass-separated neutron-deficient La and Ce isotopes

    International Nuclear Information System (INIS)

    Genevey, J.; Gizon, A.; Idrissi, N.; Weiss, B.; Beraud, R.; Charvet, A.; Duffait, R.; Emsallem, A.; Meyer, M.; Ollivier, T.; Redon, N.

    1987-01-01

    By use of a He jet system coupled to a Bernas-Nier ion-source, several new mass-separated A = 122 - 127 isotopes reached in heavy ion fusion reactions at SARA have been identified and studied. From experimental decay properties of La isotopes, systematics of low-lying energy levels have been extended for even-even and odd-A barium. New informations on Ce decay schemes are briefly reported

  13. Reference radiation fields - Simulated workplace neutron fields - Part 2: Calibration fundamentals related to the basic quantities

    International Nuclear Information System (INIS)

    2008-01-01

    ISO 8529-1, ISO 8529-2 and ISO 8529-3, deal with the production, characterization and use of neutron fields for the calibration of personal dosimeters and area survey meters. These International Standards describe reference radiations with neutron energy spectra that are well defined and well suited for use in the calibration laboratory. However, the neutron spectra commonly encountered in routine radiation protection situations are, in many cases, quite different from those produced by the sources specified in the International Standards. Since personal neutron dosimeters, and to a lesser extent survey meters, are generally quite energy dependent in their dose equivalent response, it might not be possible to achieve an appropriate calibration for a device that is used in a workplace where the neutron energy spectrum and angular distribution differ significantly from those of the reference radiation used for calibration. ISO 8529-1 describes four radionuclide based neutron reference radiations in detail. This part of ISO 12789 includes the specification of neutron reference radiations that were developed to closely resemble radiation that is encountered in practice

  14. Total Absorption Spectroscopy Study of the Beta Decay of 60Mn to Constrain the Neutron Capture Rate of 60Fe

    Science.gov (United States)

    Richman, Debra; Spyrou, Artemis; Dombos, Alex; Couture, Aaron; e15034 Collaboration

    2017-09-01

    Interest in 60Fe, a long lived radioisotope synthesized in massive stars, has recently peaked. The signature of its decay allows us to probe astrophysical processes, events such as the early formation of the solar system and nucleosynthesis. To understand these observations a complete understanding of the creation, destruction and nuclear properties of 60Fe in the astrophysical environment are required. Using the beta decay of 60Mn in conjunction with total absorption spectroscopy (TAS), made possible by the high efficiency gamma ray calorimeter SuN (Summing NaI detector) at the National Superconducting Cyclotron Laboratory (NSCL), to study the distribution of beta-decay intensity over the daughter-nucleus 60Fe, provides information about the structure of the daughter and improves the predictive power of astrophysical models. In addition to the ongoing TAS analysis, The Beta-Oslo method will be used to extract the nuclear level density and gamma-strength function of 60Fe providing much needed constraints on the neutron capture reaction rate responsible for the creation of this nucleus.

  15. Electromagnetic and Radiative Properties of Neutron Star Magnetospheres

    Science.gov (United States)

    Li, Jason G.

    2014-05-01

    Magnetospheres of neutron stars are commonly modeled as either devoid of plasma in "vacuum'' models or filled with perfectly conducting plasma with negligible inertia in "force-free'' models. While numerically tractable, neither of these idealized limits can simultaneously account for both the plasma currents and the accelerating electric fields that are needed to explain the morphology and spectra of high-energy emission from pulsars. In this work we improve upon these models by considering the structure of magnetospheres filled with resistive plasma. We formulate Ohm's Law in the minimal velocity fluid frame and implement a time-dependent numerical code to construct a family of resistive solutions that smoothly bridges the gap between the vacuum and force-free magnetosphere solutions. We further apply our method to create a self-consistent model for the recently discovered intermittent pulsars that switch between two distinct states: an "on'', radio-loud state, and an "off'', radio-quiet state with lower spin-down luminosity. Essentially, we allow plasma to leak off open field lines in the absence of pair production in the "off'' state, reproducing observed differences in spin-down rates. Next, we examine models in which the high-energy emission from gamma-ray pulsars comes from reconnecting current sheets and layers near and beyond the light cylinder. The reconnected magnetic field provides a reservoir of energy that heats particles and can power high-energy synchrotron radiation. Emitting particles confined to the sheet naturally result in a strong caustic on the skymap and double peaked light curves for a broad range of observer angles. Interpulse bridge emission likely arises from interior to the light cylinder, along last open field lines that traverse the space between the polar caps and the current sheet. Finally, we apply our code to solve for the magnetospheric structure of merging neutron star binaries. We find that the scaling of electromagnetic

  16. Some neutron and gamma radiation characteristics of plutonium cermet fuel for isotopic power sources

    Science.gov (United States)

    Neff, R. A.; Anderson, M. E.; Campbell, A. R.; Haas, F. X.

    1972-01-01

    Gamma and neutron measurements on various types of plutonium sources are presented in order to show the effects of O-17, O-18 F-19, Pu-236, age of the fuel, and size of the source on the gamma and neutron spectra. Analysis of the radiation measurements shows that fluorine is the main contributor to the neutron yields from present plutonium-molybdenum cermet fuel, while both fluorine and Pu-236 daughters contribute significantly to the gamma ray intensities.

  17. Pulsed neutron well logging apparatus having means for determining background radiation

    International Nuclear Information System (INIS)

    Randall, R.R.

    1979-01-01

    A neutron generator in a well logging instrument is periodically pulsed and has an off period between pulses of 1000 microseconds. A neutron detector is gated on at intervals of 400 to 500, 550 to 650, and 700 to 800 microseconds, respectively, following the termination of each burst of fast neutrons. Circuitry is provided for determining the background radiation and for determining the macroscopic absorption. 3 claims

  18. Criticality experiments: analysis, evaluation, and programs. 8. Prompt Neutron Decay Constants in Uranium Diluted with Matrix Material Systems

    International Nuclear Information System (INIS)

    Sanchez, Rene; Loaiza, David; Brunson, Glenn

    2001-01-01

    Rossi-Alpha measurements were performed on uranium diluted with matrix material systems to determine the prompt neutron decay constants. These constants represent an eigenvalue characteristic of these particular critical assemblies, which can be experimentally measured by the Rossi-Alpha or pulse neutron source techniques and calculated by a deterministic or Monte Carlo method. In the measurements presented in this paper, highly enriched foils diluted in various X/ 235 U ratios with polyethylene and SiO 2 , and polyethylene and aluminum were assembled to a high multiplication, and the prompt neutron decay constants were obtained by the Rossi-Alpha technique. The uranium diluted with matrix material experiments were fueled with highly enriched uranium foils. The average dimensions of the bare foils were 22.86 cm squared and 0.00762 cm thick. The foils were laminated with plastic sheets to reduce the amount of airborne contamination. Each foil weighed ∼70 g. The diluent material consisted of SiO 2 , or 6061 aluminum plates, which were embedded into polyethylene plates. The SiO 2 and aluminum plates were 22.86 cm square and 0.64 cm thick. The polyethylene plates were 39.12 cm square and 1.91 cm thick. Each polyethylene plate had a central recess whose dimensions were 22.86 cm by 22.86 cm by 0.64 cm deep and was used to accommodate the SiO 2 , or aluminum plates as well as the uranium foils. There were eight 39.12-cm-squared by 2.54-cm-thick high density polyethylene plates that form the top and bottom reflectors (four at the top and four at the bottom). Also, one of the polyethylene plates located in the center of the assembly had holes drilled in a radial direction to accommodate neutron detectors. Four 3 He detectors were placed in this plate. The 3 He detectors were 1.27 cm in diameter and ∼15 cm long. Rossi-Alpha measurements were performed at several subcritical separations for both experiments. The data were collected with a type I time analyzer (PATRM

  19. Radiation

    International Nuclear Information System (INIS)

    2013-01-01

    The chapter one presents the composition of matter and atomic theory; matter structure; transitions; origin of radiation; radioactivity; nuclear radiation; interactions in decay processes; radiation produced by the interaction of radiation with matter

  20. Hematologic status of mice submitted to sublethal total body irradiation with mixed neutron-gamma radiation

    International Nuclear Information System (INIS)

    Herodin, F.; Court, L.

    1989-01-01

    The hematologic status of mice exposed to sublethal whole body irradiation with mixed neutron-gamma radiation (mainly neutrons) is studied. A slight decrease of the blood cell count is still observed below 1 Gy. The recovery of bone marrow granulocyte-macrophage progenitors seems to require more time than after pure gamma irradiation [fr

  1. Characteristics of rotating target neutron source and its use in radiation effects studies

    International Nuclear Information System (INIS)

    Van Konynenburg, R.A.; Barschall, H.H.; Booth, R.; Wong, C.

    1975-07-01

    The Rotating Target Neutron Source (RTNS) at Lawrence Livermore Laboratory is currently the most intense source of DT fusion neutrons available for the study of radiation effects in materials. This paper will present a brief description of the machine, outline the history of its development and discuss its performance characteristics and its application to CTR materials research. (U.S.)

  2. Designing research of fast neutron radiation field based on the reactor

    International Nuclear Information System (INIS)

    Zhang Wenzhong; Zhang Xiaomin

    2009-01-01

    Based on the Tsinghua University experimental nuclear reactor neutron source, this research designed moderate theory technical scheme, and the thickness of materials in the scheme were selected by means of Monte Carlo simulating method. An fast neutron radiation field was gained. (authors)

  3. Program system for calculating streaming neutron radiation field in reactor cavity

    International Nuclear Information System (INIS)

    He Zhongliang; Zhao Shu.

    1986-01-01

    The A23 neutron albedo data base based on Monte Carlo method well agrees with SAIL albedo data base. RSCAM program system, using Monte Carlo method with albedo approach, is used to calculate streaming neutron radiation field in reactor cavity and containment operating hall. The dose rate distributions calculated with RSCAM in square concrete duct well agree with experiments

  4. Radiation dose distribution monitoring at neutron radiography facility area, Nuclear Energy Unit, Malaysia

    International Nuclear Information System (INIS)

    Abdul Razak Daud

    1995-01-01

    One experiment was carried out to get the distribution of radiation doses at the neutron radiography facilities, Nuclear Energy Unit, Malaysia. The analysis was done to evaluate the safety level of the area. The analysis was used in neutron radiography work

  5. Radiation doses from radiation sources of neutrons and photons by different computer calculation

    International Nuclear Information System (INIS)

    Siciliano, F.; Lippolis, G.; Bruno, S.G.

    1995-12-01

    In the present paper the calculation technique aspects of dose rate from neutron and photon radiation sources are covered with reference both to the basic theoretical modeling of the MERCURE-4, XSDRNPM-S and MCNP-3A codes and from practical point of view performing safety analyses of irradiation risk of two transportation casks. The input data set of these calculations -regarding the CEN 10/200 HLW container and dry PWR spent fuel assemblies shipping cask- is frequently commented as for as connecting points of input data and understanding theoric background are concerned

  6. Monte Carlo simulation of fission yields, kinetic energy, fission neutron spectrum and decay γ-ray spectrum for 232Th(n,f) reaction induced by 3H(d,n) 4He neutron source

    International Nuclear Information System (INIS)

    Zheng Wei; Zeen Yao; Changlin Lan; Yan Yan; Yunjian Shi; Siqi Yan; Jie Wang; Junrun Wang; Jingen Chen; Chinese Academy of Sciences, Shanghai

    2015-01-01

    Monte Carlo transport code Geant4 has been successfully utilised to study of neutron-induced fission reaction for 232 Th in the transport neutrons generated from 3 H(d,n) 4 He neutron source. The purpose of this work is to examine the applicability of Monte Carlo simulations for the computation of fission reaction process. For this, Monte Carlo simulates and calculates the characteristics of fission reaction process of 232 Th(n,f), such as the fission yields distribution, kinetic energy distribution, fission neutron spectrum and decay γ-ray spectrum. This is the first time to simulate the process of neutron-induced fission reaction using Geant4 code. Typical computational results of neutron-induced fission reaction of 232 Th(n,f) reaction are presented. The computational results are compared with the previous experimental data and evaluated nuclear data to confirm the certain physical process model in Geant4 of scientific rationality. (author)

  7. Comparing of γ-ray, proton and neutron radiation effects on optoelectronics for space

    International Nuclear Information System (INIS)

    Yu Qingkui; Tang Min; Meng Meng; Li Pengwei; Wen Ping; Li Haian; Tang Jiesen; Wang Sixin; Song Yamei

    2014-01-01

    We performed irradiation test on optoelectronics with γ-rays, proton and neutron. The electrical measurements were performed pre and after irradiation. The degradations induced by each radiation source was compared. (authors)

  8. Parity non-conserving effects in thermal neutron-deuteron radiative capture

    International Nuclear Information System (INIS)

    Desplanques, B.

    1985-01-01

    Predictions of parity non-conserving effects in thermal neutron-deuteron radiative capture are presented. The sensitivity of the results to models of the strong interaction as well as the validity of approximations made in previous calculations are discussed

  9. Foundations of radiation physics and radiation protection. 5. ed.; Grundlagen der Strahlungsphysik und des Strahlenschutzes

    Energy Technology Data Exchange (ETDEWEB)

    Krieger, Hanno

    2017-07-01

    The following topics are dealt with: Types of radiation and radiation fields, the atomic structure, radioactive decays, decay law, natural and artificial radioactivity, interactions of ionizing photon radiation, attenuation of neutral-particle beams, interactions of neutron radiation, interactions of charged particles, ionization and energy transfer, radiation doses, radiation protection phantoms, foundations of the radiation biology of cells, effects and risks of ionizing radiation, radiation expositions of men with ionizing radiation, radiation protection law, practical radiation protection against ionizing radiations, radiation eposures in medical radiology. (HSI)

  10. Measurement of the radiative decay of polarized muons in the MEG experiment

    Energy Technology Data Exchange (ETDEWEB)

    Baldini, A.M.; Bemporad, C.; Cei, F.; D' Onofrio, A.; Dussoni, S.; Galli, L.; Grassi, M.; Nicolo, D.; Sergiampietri, F.; Signorelli, G.; Tenchini, F. [INFN, Sezione di Pisa (Italy); Dipartimento di Fisica, Pisa Univ. (Italy); Bao, Y.; Hildebrandt, M.; Kettle, P.R.; Mtchedlishvili, A.; Papa, A.; Ritt, S. [Paul Scherrer Institut PSI, Villigen (Switzerland); Baracchini, E. [ICEPP, The University of Tokyo, Tokyo (Japan); INFN, Laboratori Nazionali di Frascati, Frascati, Rome (Italy); Berg, F.; Hodge, Z.; Rutar, G. [Paul Scherrer Institut PSI, Villigen (Switzerland); Swiss Federal Institute of Technology ETH, Zurich (Switzerland); Biasotti, M.; De Gerone, M.; Gatti, F.; Pizzigoni, G. [INFN, Sezione di Genova (Italy); Dipartimento di Fisica, Genoa Univ. (Italy); Boca, G.; Cattaneo, P.W.; De Bari, A.; Rossella, M. [INFN, Sezione di Pavia (Italy); Dipartimento di Fisica, Pavia Univ. (Italy); Cavoto, G.; Graziosi, A.; Piredda, G.; Ripiccini, E.; Voena, C. [INFN, Sezione di Roma (Italy); Dipartimento di Fisica, ' ' Sapienza' ' Univ. Rome (Italy); Chiarello, G.; Chiri, C.; Grancagnolo, F.; Panareo, M.; Pepino, A.; Tassielli, G.F. [INFN, Sezione di Lecce (Italy); Dipartimento di Matematica e Fisica, Salento Univ. Lecce (Italy); Fujii, Y.; Iwamoto, T.; Kaneko, D.; Mori, Toshinori; Nakaura, S.; Nishimura, M.; Ogawa, S.; Ootani, W.; Sawada, R.; Uchiyama, Y.; Yoshida, K. [ICEPP, The University of Tokyo, Tokyo (Japan); Grigoriev, D.N. [Budker Institute of Nuclear Physics of Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation); Novosibirsk State Technical University, Novosibirsk (Russian Federation); Novosibirsk State University, Novosibirsk (Russian Federation); Haruyama, T.; Mihara, S.; Nishiguchi, H.; Yamamoto, A. [KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Ieki, K. [Paul Scherrer Institut PSI, Villigen (Switzerland); ICEPP, The University of Tokyo, Tokyo (Japan); Ignatov, F.; Khazin, B.I.; Popov, A.; Yudin, Yu.V. [Budker Institute of Nuclear Physics of Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation); Novosibirsk State University, Novosibirsk (Russian Federation); Kang, Tae Im; Lim, G.M.A.; Molzon, W.; You, Z. [University of California, Irvine, CA (United States); Khomutov, N.; Korenchenko, A.; Kravchuk, N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Renga, F. [Paul Scherrer Institut PSI, Villigen (Switzerland); INFN, Sezione di Roma (Italy); Dipartimento di Fisica, ' ' Sapienza' ' Univ. Rome (Italy); Venturini, M. [INFN Sezione di Pisa (Italy); Dipartimento di Fisica, Pisa Univ. (Italy); Scuola Normale Superiore, Pisa (Italy); Collaboration: The MEG Collaboration

    2016-03-15

    We studied the radiative muon decay μ{sup +} → e{sup +}νanti νγ by using for the first time an almost fully polarized muon source. We identified a large sample (∝13,000) of these decays in a total sample of 1.8 x 10{sup 14} positive muon decays collected in the MEG experiment in the years 2009-2010 and measured the branching ratio B(μ{sup +} → eνanti νγ) = (6.03 ± 0.14(stat.) ± 0.53(sys.)) x 10{sup -8} for E{sub e} > 45 MeV and E{sub γ} > 40 MeV, consistent with the Standard Model prediction. The precise measurement of this decay mode provides a basic tool for the timing calibration, a normalization channel, and a strong quality check of the complete MEG experiment in the search for μ{sup +} → e{sup +}γ process. (orig.)

  11. The free radical species in polyacrylonitrile fibers induced by γ-radiation and their decay behaviors

    International Nuclear Information System (INIS)

    Liu Weihua; Wang Mouhua; Xing Zhe; Wu Guozhong

    2012-01-01

    Free radicals in vacuum, air and oxygen atmospheres were studied using electron spin resonance (ESR). Mainly two types of radicals, namely alkyl radicals and polyimine radicals, are formed in polyacrylonitrile (PAN) fibers after γ-ray irradiation. The G value of the radical formation was calculated to be 2.1 (number of radicals per 100 eV absorbed) in air at room temperature based on the ESR measurements. The radical stability and decay behaviors at room temperature and elevated temperatures were also investigated under different atmospheres. The alkyl radicals were found to be rather stable when stored in vacuum at room temperature, but they decayed via reaction with oxygen when stored in air. The alkyl radicals disappeared completely after a thermal treatment at 110 °C in vacuum, but only 15% of the polyimine radicals decayed; this indicates that polyimine radicals are more stable compared to the alkyl radicals due to their lower mobility. - Highlights: ► Radicals formed by radiation were assigned to polyimine and alkyl radicals. ► G-value of radicals was measured to be 2.1 per 100 eV. ► The radicals were found to be extremely stable in vacuum at room temperature. ► Effect of oxygen on radical decay under various conditions was studied.

  12. External meeting - Geneva University: Semileptonic and Radiative B-meson decays

    CERN Multimedia

    2007-01-01

    GENEVA UNIVERSITY ECOLE DE PHYSIQUE Département de physique nucléaire et corspusculaire 24, Quai Ernest-Ansermet 1211 GENEVE 4 - Tél : 022 379 62 73 - Fax: 022 379 69 92 Wednesday 4 April 2007 PARTICLE PHYSICS SEMINAR at 17:00 - Stückelberg Auditorium Semileptonic and Radiative B-meson decays by Dr Antonio Limosani / K2K, Japon The success of the B Factories at KEK and SLAC has furthered our knowledge of CP violation, a necessary ingredient for the creation of a matter-dominanted universe. Ever increasing data samples has ushered in a new era of precision CP measurements, in which the unitarity of the Cabibbo-Kobayashi-Maskawa matrix is examined for signs of New Physics. One of the crucial pieces of information, surprisingly, comes not from CP violation but from studies of semileptonic decays of the B mesons. I will discuss how various measurements of semileptonic and radiative B decays combine together to provide a precision measurement of the CKM matrix element |Vcb| and to determine the value of s...

  13. Analysis of coupled neutron-gamma radiations, applied to shieldings in multigroup albedo method

    International Nuclear Information System (INIS)

    Dunley, Leonardo Souza

    2002-01-01

    The principal mathematical tools frequently available for calculations in Nuclear Engineering, including coupled neutron-gamma radiations shielding problems, involve the full Transport Theory or the Monte Carlo techniques. The Multigroup Albedo Method applied to shieldings is characterized by following the radiations through distinct layers of materials, allowing the determination of the neutron and gamma fractions reflected from, transmitted through and absorbed in the irradiated media when a neutronic stream hits the first layer of material, independently of flux calculations. Then, the method is a complementary tool of great didactic value due to its clarity and simplicity in solving neutron and/or gamma shielding problems. The outstanding results achieved in previous works motivated the elaboration and the development of this study that is presented in this dissertation. The radiation balance resulting from the incidence of a neutronic stream into a shielding composed by 'm' non-multiplying slab layers for neutrons was determined by the Albedo method, considering 'n' energy groups for neutrons and 'g' energy groups for gammas. It was taken into account there is no upscattering of neutrons and gammas. However, it was considered that neutrons from any energy groups are able to produce gammas of all energy groups. The ANISN code, for an angular quadrature order S 2 , was used as a standard for comparison of the results obtained by the Albedo method. So, it was necessary to choose an identical system configuration, both for ANISN and Albedo methods. This configuration was six neutron energy groups and eight gamma energy groups, using three slab layers (iron aluminum - manganese). The excellent results expressed in comparative tables show great agreement between the values determined by the deterministic code adopted as standard and, the values determined by the computational program created using the Albedo method and the algorithm developed for coupled neutron

  14. β-delayed charged particle decays of neutron-deficient nuclei 20Mg and 23Si and 22Si

    International Nuclear Information System (INIS)

    Babo, Mathieu

    2016-01-01

    The neutron-deficient nuclei 20 Mg, 23 Si and 22 Si were produced by fragmentation at NSCL, at MSU (USA), and implanted into an array of 3 double sided stripped Si detectors, surrounded by 16 high-purity Ge detectors. This novel arrangement allowed the detection of the charged particles emitted by the unbound excited states in coincidence with the γ rays emitted by the de-excitation of the daughter. The βp decay of 20 Mg is very well-known and therefore was used to test and optimize the analysis program. The β-delayed proton transitions to the first 3 excited states in 19 Ne were identified and compared to previous measurements. The half-life, the branching ratio of the transitions and the excitation energies, including the IAS, were measured and are in good agreement with the adopted values. The study of the β+ decay of 23 Si allowed the identification of 14 excited states in 23 Al. The emission of 2 protons from the IAS was unambiguously identified. The measurement of the IAS energy allowed a better determination of the mass excess of 23 Si, giving 23.27 (7) MeV. A possible β3p decay channel was also tentatively identified. Most of the theoretical predictions are in favor of a 2-proton radioactive 22 Si. The β2p decays to the first excited state and the ground state of 20 Na were identified. The branching ratio of the decay to the IAS is 2.05 (44) %, and the IAS excitation energy was measured to be 9040 (54) keV. The additional measurement of the half-life gives T 1/2 = 30.38 (45) ms, and allowed the determination of the partial half-life. In this study, we propose a parameterization of the statistical rate function f for the superallowed Fermi β decays. This allow the first indirect mass measurement of 22 Si ground state, 31.49 (14) MeV. The two-proton threshold is then S2p = 645 (100) keV and does not allow 2p radioactivity. (author) [fr

  15. α-decay chain and associated cluster emission from neutron deficient 237Cf nucleus

    International Nuclear Information System (INIS)

    Jain, Deepika; Sharma, Manoj K.

    2015-01-01

    We have studied the α-decay chain of 237 Cf nucleus, which has been observed in the 3n evaporation channel when the semi-magic projectile 36 S strikes on 204 Pbv nucleus. The calculations are carried out by using preformed cluster model (PCM), with choices of spherical and quadruple deformation with in cold optimum orientation approach. The calculated half-lives of α-decay chain find relatively in nice agreement with experimental data for the deformed fragmentation approach. Along with α emission, the possibility of heavier clusters is also worked out and corresponding half-lives are predicted. (author)

  16. On possible contribution of a leptoquark intermediate boson mechanism in the free neutron beta decay

    International Nuclear Information System (INIS)

    Gaponov, Yu.V.

    2000-01-01

    A possible mechanism of the virtual leptoquark scalar intermediate boson exchange connected with a contribution of the right-handed nucleon currents to the free beta decay is demonstrated. The extension of the hypothesis can be associated with the realization of the same mechanism in the beta decay via the emission of right-handed neutrino (left-handed antineutrino). It is shown that a hypothesis of this kind leads to appearance of scalar and tensor terms in the effective Hamiltonian of weak interaction, and these terms include the right-handed neutrinos. The relevant experimental data are discussed [ru

  17. Experimental study of the rearrangements of valence protons and neutrons amongst single-particle orbits during double-β decay in 100Mo

    Science.gov (United States)

    Freeman, S. J.; Sharp, D. K.; McAllister, S. A.; Kay, B. P.; Deibel, C. M.; Faestermann, T.; Hertenberger, R.; Mitchell, A. J.; Schiffer, J. P.; Szwec, S. V.; Thomas, J. S.; Wirth, H.-F.

    2017-11-01

    The rearrangements of protons and neutrons amongst the valence single-particle orbitals during double-β decay of 100Mo have been determined by measuring cross sections in (d ,p ), (p ,d ), (3He,α ), and (3He,d ) reactions on Mo,10098 and Ru,102100 targets. The deduced nucleon occupancies reveal significant discrepancies when compared with theoretical calculations; the same calculations have previously been used to determine the nuclear matrix element associated with the decay probability of double-β decay of the 100Mo system.

  18. Radiation damage in stainless steel under varying temperature neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Naoaki [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1998-03-01

    Microstructural evolution of model alloys of 316SS was examined by neutron irradiation at JMTR under cyclic temperature varying condition. In the case of Fe-16Cr-17Ni, formation of interstitial loops and voids are strongly suppressed by varying the temperature from 473K to 673K. By adding Ti as miner element (0.25wt%), however, abnormal accumulation of vacancies (void swelling of 11%dpa at 0.1dpa) was observed. Theoretical analysis standing on the rate theory of defect clustering and simulation irradiation experiments with heavy ions indicates that the vacancy-rich condition which appears temporally during and after changing the temperature from low to high brings these results. It was also shown that only 1 dpa pre-irradiation at low temperature changes swelling behavior at high temperature above several 10 dpa. The understanding of non-steady-state defect processes under temperature varying irradiation is very important to estimate the radiation damage under fusion environment where short-term and long-term temperature variation is expected. (author)

  19. Dark Radiation or Warm Dark Matter from long lived particle decays in the light of Planck

    International Nuclear Information System (INIS)

    Di Bari, Pasquale; King, Stephen F.; Merle, Alexander

    2013-01-01

    Although Planck data supports the standard ΛCDM model, it still allows for the presence of Dark Radiation corresponding up to about half an extra standard neutrino species. We propose a scenario for obtaining a fractional “effective neutrino species” from a thermally produced particle which decays into a much lighter stable relic plus standard fermions. At lifetimes much longer than ∼1 s, both the relic particles and the non-thermal neutrino component contribute to Dark Radiation. By increasing the stable-to-unstable particle mass ratio, the relic particle no longer acts as Dark Radiation but instead becomes a candidate for Warm Dark Matter with mass O(1 keV–100 GeV). In both cases it is possible to address the lithium problem

  20. Search for time reversal violation in neutron decay; Recherche d'une violation de l'invariance sous le renversement du temps dans la desintegration du neutron

    Energy Technology Data Exchange (ETDEWEB)

    Gorel, P

    2006-06-15

    The topic of this thesis is the implementation of an experimental setup designed to measure the R- and N-parameters in polarized neutron decay, together with the data analysis. Four observables are necessary for this measurement: the neutron polarization, the electron momentum and both transverse components of the electron polarization. These last two are measured using a Mott polarimeter. The other observables are determined using the same detectors. The precision to be reached on the R-parameter is 0.5%. A non zero value would sign a time reversal invariance violation and therefore would be a hint of physics beyond the Standard Model. This document presents the work done to prepare and optimize the experimental setup before the data acquisition run performed in 2004. Particular care was taken on the scintillator walls, used to trigger the acquisition and measure the electron energy. The second part concerns the implementation of methods to extract R and N from the data, and the study of the background recorded simultaneously. (author)

  1. Experimental Determination of the Neutron Radiation-Dose Distribution in the Human Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Stipcic, Neda [Institute Rudjer Bogkovic, Zagreb, Yugoslavia (Serbia)

    1967-01-15

    The quality of the radiation delivering the radiation dose to the human phantom is quite different from that of the incident neutron beam. This paper describes the experimental investigation of the variation of neutron dose related to the variation of neutron fluence with depth in the human phantom. The distribution of neutron radiation was determined in the human phantom - a cube of paraffin wax 25 cm x 25 cm x 50 cm with a density of 0.92 cm{sup -3}. Po-Be and Ra-Be point sources were used as neutron sources. Neutron fluences were measured using different types of detector: scintillation detector, BF{sub 3} counter, and nuclear-track emulsions. Since the fluence measurements with these three types of detectors were carried out under the same experimental conditions, it was possible to separate and analyse each part of the radiation dose in the paraffin. From the investigations, the distribution of the total radiation dose was obtained as a function of the paraffin depth. The maximum value of this dose distribution is constant with respect to the distance between the source and the paraffin phantom. From the results obtained, some conclusions may be drawn concerning the amount of absorbed radiation dose in the human phantom. (author)

  2. Silicon photo-multiplier radiation hardness tests with a beam controlled neutron source

    International Nuclear Information System (INIS)

    Angelone, M.; Pillon, M.; Faccini, R.; Pinci, D.; Baldini, W.; Calabrese, R.; Cibinetto, G.; Cotta Ramusino, A.; Malaguti, R.; Pozzati, M.

    2010-01-01

    Radiation hardness tests were performed at the Frascati Neutron Generator on silicon Photo-Multipliers that were made of semiconductor photon detectors built from a square matrix of avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated, integrating up to 7x10 10 1-MeV-equivalent neutrons per cm 2 . Detector performance was recorded during the neutron irradiation, and a gradual deterioration of their properties began after an integrated fluence of the order of 10 8 1-MeV-equivalent neutrons per cm 2 was reached.

  3. Combined treatment of UV and gamma radiation of papaya for decay control

    International Nuclear Information System (INIS)

    Moy, J.H.; McElhaney, T.; Matsuzaki, C.; Piedrahita, C.

    1978-01-01

    An exploratory study was made to determine if combining u.v. and gamma radiation treatment at selective doses would decrease the fungal decay incidence in papaya (Carica papaya L. var. Solo), and thereby increase the marketable life of the fruit. Also studied was the effect of the combined treatment on the spores of Aschochyta spp., Colletotrichium spp. and Phytophthora spp., which are commonly found on papaya grown in Hawaii. This was to test the postulate that the combined treatment would prevent photoreactivation of the disrupted nuclei in microorganisms and lead to eventual death. Experimental results did not indicate a conclusive trend to effectiveness but suggested a number of problems to be resolved before the treatment can become useful in fungal decay control of fruits. (author)

  4. First Experimental Study of Photon Polarization in Radiative B_{s}^{0} Decays.

    Science.gov (United States)

    Aaij, R; Adeva, B; Adinolfi, M; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Andreassi, G; Andreotti, M; Andrews, J E; Appleby, R B; Archilli, F; d'Argent, P; Arnau Romeu, J; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Babuschkin, I; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baker, S; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Baszczyk, M; Batozskaya, V; Batsukh, B; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Bel, L J; Bellee, V; Belloli, N; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bertolin, A; Betti, F; Bettler, M-O; van Beuzekom, M; Bezshyiko, I; Bifani, S; Billoir, P; Bird, T; Birnkraut, A; Bitadze, A; Bizzeti, A; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Boettcher, T; Bondar, A; Bondar, N; Bonivento, W; Borgheresi, A; Borghi, S; Borisyak, M; Borsato, M; Bossu, F; Boubdir, M; Bowcock, T J V; Bowen, E; Bozzi, C; Braun, S; Britsch, M; Britton, T; Brodzicka, J; Buchanan, E; Burr, C; Bursche, A; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Campora Perez, D; Campora Perez, D H; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Cavallero, G; Cenci, R; Charles, M; Charpentier, Ph; Chatzikonstantinidis, G; Chefdeville, M; Chen, S; Cheung, S-F; Chobanova, V; Chrzaszcz, M; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collazuol, G; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombs, G; Coquereau, S; Corti, G; Corvo, M; Costa Sobral, C M; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Da Cunha Marinho, F; Dall'Occo, E; Dalseno, J; David, P N Y; Davis, A; De Aguiar Francisco, O; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Serio, M; De Simone, P; Dean, C-T; Decamp, D; Deckenhoff, M; Del Buono, L; Demmer, M; Derkach, D; Deschamps, O; Dettori, F; Dey, B; Di Canto, A; Dijkstra, H; Dordei, F; Dorigo, M; Dosil Suárez, A; Dovbnya, A; Dreimanis, K; Dufour, L; Dujany, G; Dungs, K; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Déléage, N; Easo, S; Ebert, M; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; Elsasser, Ch; Ely, S; Esen, S; Evans, H M; Evans, T; Falabella, A; Farley, N; Farry, S; Fay, R; Fazzini, D; Ferguson, D; Fernandez Albor, V; Fernandez Prieto, A; Ferrari, F; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fini, R A; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fleuret, F; Fohl, K; Fontana, M; Fontanelli, F; Forshaw, D C; Forty, R; Franco Lima, V; Frank, M; Frei, C; Fu, J; Furfaro, E; Färber, C; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; Garcia Martin, L M; García Pardiñas, J; Garra Tico, J; Garrido, L; Garsed, P J; Gascon, D; Gaspar, C; Gavardi, L; Gazzoni, G; Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianì, S; Gibson, V; Girard, O G; Giubega, L; Gizdov, K; Gligorov, V V; Golubkov, D; Golutvin, A; Gomes, A; Gorelov, I V; Gotti, C; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Griffith, P; Grillo, L; Gruberg Cazon, B R; Grünberg, O; Gushchin, E; Guz, Yu; Gys, T; Göbel, C; Hadavizadeh, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hatch, M; He, J; Head, T; Heister, A; Hennessy, K; Henrard, P; Henry, L; Hernando Morata, J A; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hombach, C; Hopchev, H; Hulsbergen, W; Humair, T; Hushchyn, M; Hussain, N; Hutchcroft, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jawahery, A; Jiang, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Kanso, W; Karacson, M; Kariuki, J M; Karodia, S; Kecke, M; Kelsey, M; Kenyon, I R; Kenzie, M; Ketel, T; Khairullin, E; Khanji, B; Khurewathanakul, C; Kirn, T; Klaver, S; Klimaszewski, K; Koliiev, S; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Kosmyntseva, A; Kozachuk, A; Kozeiha, M; Kravchuk, L; Kreplin, K; Kreps, M; Krokovny, P; Kruse, F; Krzemien, W; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kuonen, A K; Kurek, K; Kvaratskheliya, T; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J-P; Leflat, A; Lefrançois, J; Lefèvre, R; Lemaitre, F; Lemos Cid, E; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Likhomanenko, T; Lindner, R; Linn, C; Lionetto, F; Liu, B; Liu, X; Loh, D; Longstaff, I; Lopes, J H; Lucchesi, D; Lucio Martinez, M; Luo, H; Lupato, A; Luppi, E; Lupton, O; Lusiani, A; Lyu, X; Machefert, F; Maciuc, F; Maev, O; Maguire, K; Malde, S; Malinin, A; Maltsev, T; Manca, G; Mancinelli, G; Manning, P; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marino, P; Marks, J; Martellotti, G; Martin, M; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massacrier, L M; Massafferri, A; Matev, R; Mathad, A; Mathe, Z; Matteuzzi, C; Mauri, A; Maurin, B; Mazurov, A; McCann, M; McCarthy, J; McNab, A; McNulty, R; Meadows, B; Meier, F; Meissner, M; Melnychuk, D; Merk, M; Merli, A; Michielin, E; Milanes, D A; Minard, M-N; Mitzel, D S; Mogini, A; Molina Rodriguez, J; Monroy, I A; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Moron, J; Morris, A B; Mountain, R; Muheim, F; Mulder, M; Mussini, M; Müller, D; Müller, J; Müller, K; Müller, V; Naik, P; Nakada, T; Nandakumar, R; Nandi, A; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, A D; Nguyen-Mau, C; Nieswand, S; Niet, R; Nikitin, N; Nikodem, T; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Oldeman, R; Onderwater, C J G; Otalora Goicochea, J M; Otto, A; Owen, P; Oyanguren, A; Pais, P R; Palano, A; Palombo, F; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parker, W; Parkes, C; Passaleva, G; Pastore, A; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petrov, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pikies, M; Pinci, D; Pistone, A; Piucci, A; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Pomery, G J; Popov, A; Popov, D; Popovici, B; Poslavskii, S; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rama, M; Ramos Pernas, M; Rangel, M S; Raniuk, I; Raven, G; Redi, F; Reichert, S; Dos Reis, A C; Remon Alepuz, C; Renaudin, V; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Rogozhnikov, A; Roiser, S; Rollings, A; Romanovskiy, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Rudolph, M S; Ruf, T; Ruiz Valls, P; Saborido Silva, J J; Sadykhov, E; Sagidova, N; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schael, S; Schellenberg, M; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schubert, K; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sergi, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Shires, A; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Simone, S; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, E; Smith, I T; Smith, J; Smith, M; Snoek, H; Sokoloff, M D; Soler, F J P; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefko, P; Stefkova, S; Steinkamp, O; Stemmle, S; Stenyakin, O; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Sun, L; Sutcliffe, W; Swientek, K; Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Tellarini, G; Teubert, F; Thomas, E; van Tilburg, J; Tilley, M J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Toriello, F; Tournefier, E; Tourneur, S; Trabelsi, K; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tully, A; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valassi, A; Valat, S; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Venkateswaran, A; Vernet, M; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Vilasis-Cardona, X; Volkov, V; Vollhardt, A; Voneki, B; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Vázquez Sierra, C; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Wark, H M; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wright, S; Wyllie, K; Xie, Y; Xing, Z; Xu, Z; Yang, Z; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zarebski, K A; Zavertyaev, M; Zhang, L; Zhang, Y; Zhang, Y; Zhelezov, A; Zheng, Y; Zhokhov, A; Zhu, X; Zhukov, V; Zucchelli, S

    2017-01-13

    The polarization of photons produced in radiative B_{s}^{0} decays is studied for the first time. The data are recorded by the LHCb experiment in pp collisions corresponding to an integrated luminosity of 3  fb^{-1} at center-of-mass energies of 7 and 8 TeV. A time-dependent analysis of the B_{s}^{0}→ϕγ decay rate is conducted to determine the parameter A^{Δ}, which is related to the ratio of right- over left-handed photon polarization amplitudes in b→sγ transitions. A value of A^{Δ}=-0.98_{-0.52}^{+0.46}_{-0.20}^{+0.23} is measured. This result is consistent with the standard model prediction within 2 standard deviations.

  5. Electromagnetic radiation by parametric decay of upper hybrid waves in ionospheric modification experiments

    International Nuclear Information System (INIS)

    Leyser, T.B.

    1994-01-01

    A nonlinear dispersion relation for the parametric decay of an electrostatic upper hybrid wave into an ordinary mode electromagnetic wave, propagating parallel to the ambient magnetic field, and an electrostatic low frequency wave, being either a lower hybrid wave or a high harmonic ion Bernstein wave, is derived. The coherent and resonant wave interaction is considered to take place in a weakly magnetized and collisionless Vlasov plasma. The instability growth rate is computed for parameter values typical of ionospheric modification experiments, in which a powerful high frequency electromagnetic pump wave is injected into the ionospheric F-region from ground-based transmitters. The electromagnetic radiation which is excited by the decaying upper hybrid wave is found to be consistent with the prominent and commonly observed downshifted maximum (DM) emission in the spectrum of stimulated electromagnetic emission

  6. First experimental study of photon polarization in radiative $B^{0}_{s}$ decays

    CERN Document Server

    Aaij, Roel; Adinolfi, Marco; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Andreassi, Guido; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Archilli, Flavio; d'Argent, Philippe; Arnau Romeu, Joan; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Babuschkin, Igor; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baker, Sophie; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Baszczyk, Mateusz; Batozskaya, Varvara; Batsukh, Baasansuren; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Bel, Lennaert; Bellee, Violaine; Belloli, Nicoletta; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Betti, Federico; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bezshyiko, Iaroslava; Bifani, Simone; Billoir, Pierre; Bird, Thomas; Birnkraut, Alex; Bitadze, Alexander; Bizzeti, Andrea; Blake, Thomas; Blanc, Frederic; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Boettcher, Thomas; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borgheresi, Alessio; Borghi, Silvia; Borisyak, Maxim; Borsato, Martino; Bossu, Francesco; Boubdir, Meriem; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Buchanan, Emma; Burr, Christopher; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Camboni, Alessandro; Campana, Pierluigi; Campora Perez, Daniel; Campora Perez, Daniel Hugo; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chatzikonstantinidis, Georgios; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chobanova, Veronika; Chrzaszcz, Marcin; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombs, George; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Costa Sobral, Cayo Mar; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Da Cunha Marinho, Franciole; Dall'Occo, Elena; Dalseno, Jeremy; David, Pieter; Davis, Adam; De Aguiar Francisco, Oscar; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Serio, Marilisa; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Demmer, Moritz; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Dijkstra, Hans; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dungs, Kevin; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Déléage, Nicolas; Easo, Sajan; Ebert, Marcus; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Farley, Nathanael; Farry, Stephen; Fay, Robert; Fazzini, Davide; Ferguson, Dianne; Fernandez Albor, Victor; Fernandez Prieto, Antonio; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fini, Rosa Anna; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fleuret, Frederic; Fohl, Klaus; Fontana, Marianna; Fontanelli, Flavio; Forshaw, Dean Charles; Forty, Roger; Franco Lima, Vinicius; Frank, Markus; Frei, Christoph; Fu, Jinlin; Furfaro, Emiliano; Färber, Christian; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; Garcia Martin, Luis Miguel; García Pardiñas, Julián; Garra Tico, Jordi; Garrido, Lluis; Garsed, Philip John; Gascon, David; Gaspar, Clara; Gavardi, Laura; Gazzoni, Giulio; Gerick, David; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianì, Sebastiana; Gibson, Valerie; Girard, Olivier Göran; Giubega, Lavinia-Helena; Gizdov, Konstantin; Gligorov, V.V.; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gorelov, Igor Vladimirovich; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graverini, Elena; Graziani, Giacomo; Grecu, Alexandru; Griffith, Peter; Grillo, Lucia; Gruberg Cazon, Barak Raimond; Grünberg, Oliver; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Göbel, Carla; Hadavizadeh, Thomas; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; Hatch, Mark; He, Jibo; Head, Timothy; Heister, Arno; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hombach, Christoph; Hopchev, P H; Hulsbergen, Wouter; Humair, Thibaud; Hushchyn, Mikhail; Hussain, Nazim; Hutchcroft, David; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jawahery, Abolhassan; Jiang, Feng; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Kariuki, James Mwangi; Karodia, Sarah; Kecke, Matthieu; Kelsey, Matthew; Kenyon, Ian; Kenzie, Matthew; Ketel, Tjeerd; Khairullin, Egor; Khanji, Basem; Khurewathanakul, Chitsanu; Kirn, Thomas; Klaver, Suzanne; Klimaszewski, Konrad; Koliiev, Serhii; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Kosmyntseva, Alena; Kozachuk, Anastasiia; Kozeiha, Mohamad; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krokovny, Pavel; Kruse, Florian; Krzemien, Wojciech; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kuonen, Axel Kevin; Kurek, Krzysztof; Kvaratskheliya, Tengiz; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lanfranchi, Gaia; Langenbruch, Christoph; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Leflat, Alexander; Lefrançois, Jacques; Lefèvre, Regis; Lemaitre, Florian; Lemos Cid, Edgar; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Liu, Xuesong; Loh, David; Longstaff, Iain; Lopes, Jose; Lucchesi, Donatella; Lucio Martinez, Miriam; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Lusiani, Alberto; Lyu, Xiao-Rui; Machefert, Frederic; Maciuc, Florin; Maev, Oleg; Maguire, Kevin; Malde, Sneha; Malinin, Alexander; Maltsev, Timofei; Manca, Giulia; Mancinelli, Giampiero; Manning, Peter Michael; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Marks, Jörg; Martellotti, Giuseppe; Martin, Morgan; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massacrier, Laure Marie; Massafferri, André; Matev, Rosen; Mathad, Abhijit; Mathe, Zoltan; Matteuzzi, Clara; Mauri, Andrea; Maurin, Brice; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; Meadows, Brian; Meier, Frank; Meissner, Marco; Melnychuk, Dmytro; Merk, Marcel; Merli, Andrea; Michielin, Emanuele; Milanes, Diego Alejandro; Minard, Marie-Noelle; Mitzel, Dominik Stefan; Mogini, Andrea; Molina Rodriguez, Josue; Monroy, Ignacio Alberto; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Mulder, Mick; Mussini, Manuel; Müller, Dominik; Müller, Janine; Müller, Katharina; Müller, Vanessa; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nandi, Anita; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen-Mau, Chung; Nieswand, Simon; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Ogilvy, Stephen; Oldeman, Rudolf; Onderwater, Gerco; Otalora Goicochea, Juan Martin; Otto, Adam; Owen, Patrick; Oyanguren, Maria Aranzazu; Pais, Preema Rennee; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parker, William; Parkes, Christopher; Passaleva, Giovanni; Pastore, Alessandra; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pearce, Alex; Pellegrino, Antonio; Penso, Gianni; Pepe Altarelli, Monica; Perazzini, Stefano; Perret, Pascal; Pescatore, Luca; Petridis, Konstantinos; Petrolini, Alessandro; Petrov, Aleksandr; Petruzzo, Marco; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pikies, Malgorzata; Pinci, Davide; Pistone, Alessandro; Piucci, Alessio; Playfer, Stephen; Plo Casasus, Maximo; Poikela, Tuomas; Polci, Francesco; Poluektov, Anton; Polyakov, Ivan; Polycarpo, Erica; Pomery, Gabriela Johanna; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Poslavskii, Stanislav; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Quagliani, Renato; Rachwal, Bartolomiej; Rademacker, Jonas; Rama, Matteo; Ramos Pernas, Miguel; Rangel, Murilo; Raniuk, Iurii; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; dos Reis, Alberto; Remon Alepuz, Clara; Renaudin, Victor; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vicente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Lopez, Jairo Alexis; Rodriguez Perez, Pablo; Rogozhnikov, Alexey; Roiser, Stefan; Rollings, Alexandra Paige; Romanovskiy, Vladimir; Romero Vidal, Antonio; Ronayne, John William; Rotondo, Marcello; Rudolph, Matthew Scott; Ruf, Thomas; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sadykhov, Elnur; Sagidova, Naylya; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santimaria, Marco; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrina, Darya; Schael, Stefan; Schellenberg, Margarete; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmelzer, Timon; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schubert, Konstantin; Schubiger, Maxime; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Semennikov, Alexander; Sergi, Antonino; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Siddi, Benedetto Gianluca; Silva Coutinho, Rafael; Silva de Oliveira, Luiz Gustavo; Simi, Gabriele; Simone, Saverio; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Eluned; Smith, Iwan Thomas; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Souza De Paula, Bruno; Spaan, Bernhard; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Stefko, Pavol; Stefkova, Slavorima; Steinkamp, Olaf; Stemmle, Simon; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Syropoulos, Vasileios; Szczekowski, Marek; Szumlak, Tomasz; T'Jampens, Stephane; Tayduganov, Andrey; Tekampe, Tobias; Tellarini, Giulia; Teubert, Frederic; Thomas, Eric; van Tilburg, Jeroen; Tilley, Matthew James; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Toriello, Francis; Tournefier, Edwige; Tourneur, Stephane; Trabelsi, Karim; Traill, Murdo; Tran, Minh Tâm; Tresch, Marco; Trisovic, Ana; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tully, Alison; Tuning, Niels; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valassi, Andrea; Valat, Sebastien; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vecchi, Stefania; van Veghel, Maarten; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Venkateswaran, Aravindhan; Vernet, Maxime; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Volkov, Vladimir; Vollhardt, Achim; Voneki, Balazs; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; de Vries, Jacco; Vázquez Sierra, Carlos; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wang, Jianchun; Ward, David; Wark, Heather Mckenzie; Watson, Nigel; Websdale, David; Weiden, Andreas; Whitehead, Mark; Wicht, Jean; Wilkinson, Guy; Wilkinson, Michael; Williams, Mark Richard James; Williams, Matthew; Williams, Mike; Williams, Timothy; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wraight, Kenneth; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yin, Hang; Yu, Jiesheng; Yuan, Xuhao; Yushchenko, Oleg; Zarebski, Kristian Alexander; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Yanxi; Zhang, Yu; Zhelezov, Alexey; Zheng, Yangheng; Zhokhov, Anatoly; Zhu, Xianglei; Zhukov, Valery; Zucchelli, Stefano

    2017-01-09

    The polarization of photons produced in radiative $B^{0}_{s}$ decays is studied for the first time. The data are recorded by the LHCb experiment in $pp$ collisions corresponding to an integrated luminosity of 3fb$^{-1}$ at center-of-mass energies of $7$ and $8$TeV. A time-dependent analysis of the $B^{0}_{s} \\to \\phi \\gamma$ decay rate is conducted to determine the parameter ${\\mathcal{A}}^\\Delta$, which is related to the ratio of right- over left-handed photon polarization amplitudes in $b \\to s \\gamma$ transitions. A value of ${\\mathcal{A}}^\\Delta=-0.98^{\\,+0.46\\,+0.23}_{\\,-0.52\\,-0.20}$ is measured. This result is consistent with the Standard Model prediction within two standard deviations.

  7. Measurement of A and B coefficients in the decay of polarized neutrons

    DEFF Research Database (Denmark)

    Christensen, Carl Jørgen; Krohn, V.E.; Ringo, G.R.

    1969-01-01

    The coefficients found were A = −0.115 ± 0.008 and B = 1.01 ± 0.04. The value of A leads to |GA/GV| = = 1.26 ± 0.02 for the ratio of coupling constants in beta decay, and B is consistent with GS = GT = 0....

  8. Nuclear structure from radioactive decay

    International Nuclear Information System (INIS)

    Wood, J.L.

    1991-01-01

    This report discusses nuclear structure from radioactive decay of the following: Neutron-Deficient Iridium Isotopes; Neutron-Deficient Platinum Isotopes; Neutron-Deficient Gold Isotopes; Neutron-Deficient Mercury Isotopes; Neutron-Deficient Thallium Isotopes; Neutron-Deficient Lead Isotopes; Neutron-Deficient Samarium Isotopes; Neutron-Deficient Promethium Isotopes; Neutron-Deficient Neodymium Isotopes; and Neutron-Deficient Praseodymium Isotopes. Also discussed are Nuclear Systematics and Models

  9. The characters and developments of therapy and research of neutron-induced acute radiation sickness

    International Nuclear Information System (INIS)

    Wang Xinru; Luo Qingliang; Wang Baoqing; Dong Shukui

    2003-01-01

    Neutron radiation will exert seriously lesions on body and lead to acute radiation sickness (ARS). Neutron induced ARS is characterized by complicated symptoms of gastrointestinal, high earlier death rate and lacking of specially therapeutic approaches. The primarily curable method is to treat patients with comprehensive means such as anti-infection, anti-bleeding and blood infusion, et. Cytokines can improve the hematopoietic functions of bone marrow. With the rapid development of the molecular biology and the emergence of cytokines such as recombinant human interleukin-11 that could help the regeneration of the gastrointestinal mucosa, neutron-induced ARS will be treated with new methods

  10. Radiation hazards due to activated corrosion and neutron sputtering products in fusion reactor coolant and tritium breeding fluids

    International Nuclear Information System (INIS)

    Klein, A.C.; Vogelsang, W.F.

    1985-01-01

    The accumulation of radioactive corrosion and neutron sputtering products on the surfaces of components in fusion reactor coolant and tritium breeding systems can cause significant personnel access problems. Remote maintenance techniques or special treatment may be required to limit the amount of radiation exposure to plant operational and maintenance personnel. A computer code, RAPTOR, has been developed to estimate the transport of this activated material throughout a fusion heat transfer and/or tritium breeding material loop. A method is devised which treats the components of the loop individually and determines the source rates, deposition and erosion rates, decay rates, and purification rates of these radioactive materials. RAPTOR has been applied to the MARS and Starfire conceptual reactor designs to determine the degree of the possible radiation hazard due to these products. Due to the very high corrosion release rate by HT-9 when exposed to LiPb in the MARS reactor design, the radiation fields surrounding the primary system will preclude direct contact maintenance even after shutdown. Even the removal of the radioactive LiPb from the system will not decrease the radiation fields to reasonable levels. The Starfire primary system will exhibit radiation fields similar to those found in present pressurized water reactors. (orig.)

  11. Measurement of Relative Biological Effectiveness (RBE) for the Radiation Beam from Neutron Source Reactor YAYOI -Comparisons with Cyclotron Neutron and 60Co Gamma Ray-

    OpenAIRE

    HIROAKI, WAKABAYASHI; SHOZO, SUZUKI; AKIRA, ITO; Nuclear Engineering Research Laboratory, Faculty of Engineering, the University of Tokyo; Institute of Medical Science, the University of Tokyo; Institute of Medical Science, the University of Tokyo

    1983-01-01

    Radiation biology and/or therapy research and development for a research reactor beam need specific RBEs of neutrons as well as of specific reactions. RBEs for reactor beams measured in situ condition are interesting because actual radiation effects on each biological system are different depending on detailed conditions of irradiation. A small powered research reactor (Fast Neutron Source Reactor: YAYOI) was examined here as a neutron beam source for obtaining survival curves in a manner usu...

  12. An experiment to measure lambda=G sub A /G sub V from a combination of angular correlation coefficients in the beta decay of polarized neutrons

    CERN Document Server

    Kuznetsov, I A; Serebrov, A P; Solovei, V A; Stepanenko, I V; Vasilev, A V; Mostovoy, Y A; Zimmer, O; Yerozolimsky, B G; Dewey, M S; Wietfeldt, F E

    2000-01-01

    A technique is described which allows us to measure the ratio lambda=G sub A /G sub V of the weak axial-vector and vector coupling constants in neutron decay without any measurement of the neutron beam polarization. lambda is determined from a combination of the parity-odd angular correlations sigma-> centre dot p-> sub e and sigma-> centre dot p-> subnu between the neutron spin sigma-> and the electron momentum p-> sub e and the anti-neutrino momentum p-> subnu, respectively, both of which are measured in a single experiment using the same neutron beam. A description of the experiment and the results of the first run at the cold neutron beam facility at the Institut Laue-Langevin are presented.

  13. Nominal effective radiation doses delivered during clinical trials of boron neutron capture therapy

    International Nuclear Information System (INIS)

    Capala, J.; Diaz, A.Z.; Chanana, A.D.

    1997-01-01

    Boron neutron capture therapy (BNCT) is a binary system that, in theory, should selectively deliver lethal, high linear energy transfer (LET) radiation to tumor cells dispersed within normal tissues. It is based on the nuclear reaction 10-B(n, α)7-Li, which occurs when the stable nucleus of boron-10 captures a thermal neutron. Due to the relatively high cross-section of the 10-B nucleus for thermal neutron capture and short ranges of the products of this reaction, tumor cells in the volume exposed to thermal neutrons and containing sufficiently high concentration of 10-B would receive a much higher radiation dose than the normal cells contained within the exposed volume. Nevertheless, radiation dose deposited in normal tissue by gamma and fast neutron contamination of the neutron beam, as well as neutron capture in nitrogen, 14-N(n,p)14-C, hydrogen, 1-H(n,γ)2-H, and in boron present in blood and normal cells, limits the dose that can be delivered to tumor cells. It is, therefore, imperative for the success of the BNCT the dosed delivered to normal tissues be accurately determined in order to optimize the irradiation geometry and to limit the volume of normal tissue exposed to thermal neutrons. These are the major objectives of BNCT treatment planning

  14. The decay of hot dysprosium nuclei

    International Nuclear Information System (INIS)

    Atac, A.; Rekstad, J.; Guttormsen, M.; Messelt, S.; Ramsoey, T.; Thorsteinsen, T.F.; Loevhoeiden, G.; Roedland, T.

    1987-03-01

    The γ-decay following the 162,163 Dy( 3 He,αxn) reactions with E 3 He =45 MeV has been studied. Non-statistical γ-radiation with energies of E γ ≅1 MeV and ≅2 MeV is found for various residual nuclei. The properties of these γ-ray bumps depend on the number of emitted neutrons and reveal an odd-even mass dependence. New techniques to extract average neutron energies as a function of excitation energy and of the number of emitted neutrons are employed. The deduced neutron energies are consistent with Fermi-gas model predictions

  15. Effect of reactor neutron radiation and temperature on the structure of InP single crystals

    International Nuclear Information System (INIS)

    Bojko, V.M.; Kolin, N.G.; Merkurisov, D.I.; Bublik, V.T.; Voronova, M.I.; Shcherbachev, K.D.

    2006-01-01

    The structural characteristics of InP single crystals have been investigated depending on the radiation effects produced by fast and full spectrum neutrons and subsequent heat treatment. A lattice period in InP single crystals decreases under neutron irradiation. Fast neutrons make the main contribution into the change of the lattice period. Availability of the thermal neutrons initiates the formation of Sn atoms, but does not make a significant influence on the change of the lattice period. Heat treatment of the irradiated samples up to 600 deg C causes the annealing of radiation defects and recovery of the lattice period. With increasing neutron fluences a lattice period becomes even higher than before irradiation [ru

  16. Radiation shielding design of BNCT treatment room for D-T neutron source.

    Science.gov (United States)

    Pouryavi, Mehdi; Farhad Masoudi, S; Rahmani, Faezeh

    2015-05-01

    Recent studies have shown that D-T neutron generator can be used as a proper neutron source for Boron Neutron Capture Therapy (BNCT) of deep-seated brain tumors. In this paper, radiation shielding calculations have been conducted based on the computational method for designing a BNCT treatment room for a recent proposed D-T neutron source. By using the MCNP-4C code, the geometry of the treatment room has been designed and optimized in such a way that the equivalent dose rate out of the treatment room to be less than 0.5μSv/h for uncontrolled areas. The treatment room contains walls, monitoring window, maze and entrance door. According to the radiation protection viewpoint, dose rate results of out of the proposed room showed that using D-T neutron source for BNCT is safe. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Radiative decays of the psi prime to all-photon final states

    International Nuclear Information System (INIS)

    Lee, R.A.

    1985-06-01

    Results of studies of selected radiative decays of the psi' to charmonium and non-charmonium states which decay into photons are presented. These studies were performed using a sample of 1.8 x 10 6 produced psi''s collected by the Crystal Ball detector at the SPEAR electron-positron storage ring. The branching ratios of the chi 0 , chi 2 , and eta'/sub c/ to two photons have been measured to be (4.5 +- 2.2 +- 2.0) x 10 -4 , (9.5 +- 2.9 +- 4.5) x 10 -4 (first errors statistical, second systematic), and -2 (90% C.L.). The signal from the decay chain psi' → γchi 0 , chi 0 → π 0 π 0 has been observed with essentially no background. Using the observed line shape of the radiative photon in this reaction, the full width of the psi 0 has been found to be 8.8 +- 1.3 +- 1.5 MeV/c 2 . In addition, the branching ratios of the chi 0 and chi 2 to π 0 π 0 have been measured to be (3.5 +- 0.3 +- 1.2) x 10 -3 and (1.2 +- 0.2 +- 0.4) x 10 -3 ; the branching ratios of the chi 0 and chi 2 to eta eta have been measured to be (2.8 +- 0.9 +- 1.3) x 10 -3 and (8.4 +- 4.2 +- 4.0) x 10 -4 . The decays of the psi' to four non-charmonium states have been investigated. The branching ratios and upper limits of these decays have been normalized to the branching ratios of the corresponding decays from the J/psi which have been measured using a sample of 2.2 x 10 6 produced J/psi's collected by the Crystal Ball detector. The ratios of the psi' branching ratios to the J/psi branching ratios for the final states γeta, γeta', γtheta, and γf have been measured to be <1.8%, <2.6%, <10 to 15%, and 9 +- 3%. These results are compared with the theoretical expectations of lowest-order quantum chromodynamics potential models. Substantial disagreement is found between theory and experiment

  18. Radiation Shielding Information Center: a source of computer codes and data for fusion neutronics studies

    International Nuclear Information System (INIS)

    McGill, B.L.; Roussin, R.W.; Trubey, D.K.; Maskewitz, B.F.

    1980-01-01

    The Radiation Shielding Information Center (RSIC), established in 1962 to collect, package, analyze, and disseminate information, computer codes, and data in the area of radiation transport related to fission, is now being utilized to support fusion neutronics technology. The major activities include: (1) answering technical inquiries on radiation transport problems, (2) collecting, packaging, testing, and disseminating computing technology and data libraries, and (3) reviewing literature and operating a computer-based information retrieval system containing material pertinent to radiation transport analysis. The computer codes emphasize methods for solving the Boltzmann equation such as the discrete ordinates and Monte Carlo techniques, both of which are widely used in fusion neutronics. The data packages include multigroup coupled neutron-gamma-ray cross sections and kerma coefficients, other nuclear data, and radiation transport benchmark problem results

  19. Residual stress evaluation by neutron and synchrotron radiation

    International Nuclear Information System (INIS)

    Lodini, A.

    2000-01-01

    This lecture is dedicated to the residual stress evaluation using neutron and X ray synchrotron radiation. Residual stress evaluation is an important step for the improvement or the performance of materials, the control of the deformation of the components and the understanding of industrial process. In general, residual stress has various origins: mechanical, thermal, thermomechanical or thermochemical. In general, these residual stresses are caused by plastic deformation, or some source of local incompatibilities and are generated by three fundamental physical origins: plastic flow, volume change and thermal dilatation. These incompatibilities are compensated for partly by the elastic deformation that generates some internal stresses. In the solid, these local incompatibilities are caused by crystal defects. The exact origin of a stress is going to depend on the scale of observation. A classification of the residual stresses in three orders, related to the scale on which one considers materials, is proposed. The diffraction method for determination of macrostresses is based on the measurement of interplanar spacing for various direction in a diffraction experiment. Different examples are proposed. Polycrystalline grains or composite have different physical and elastic properties hence the stress for a particular grains or phase differs from the average value (value of macrostress). This difference is defined as the second order stress. The second order stresses occur because of small scale anisotropy or inhomogeneity in the material : for example, due to mismatch in coefficient of thermal expansion, elastic constants or plastic flow. However, the second order stress averaged over all grains or phase is not equal to zero and this average is called the mismatch stress. Using the experimental macro stress it is possible to calculate the mismatch stresses. More recently, this technique of diffraction has also been applied for the determination of microstrain (third

  20. Study of neutron radiation effects on MOS structures

    International Nuclear Information System (INIS)

    Vaidya, Sangeeta J.

    2003-01-01

    We have studied charge trapping in the oxide and generation of interface states due to neutrons. It is observed that neutrons, though uncharged, are capable of causing ionization and interface damage and it is significant under biased irradiation conditions. One of the important features of this work is that neutron irradiation was carried out in a nuclear reactor (swimming pool type) itself in contrast to the earlier reported work which used separate neutron sources for similar studies. To simulate real life situations, all our devices were biased during irradiation. In our belief, both of these facts gave credence to our observed experimental results. (author)

  1. Radioactivity induced by neutrons: Enrico Fermi and a thermodynamic approach to radiative capture

    Science.gov (United States)

    De Gregorio, Alberto

    2006-07-01

    When Fermi learned that slow neutrons are much more effective than fast ones in inducing radioactivity, he explained this phenomenon by mentioning the well-known scattering cross section between neutrons and protons. At this early stage, he did not refer to the capture cross section by target nuclei. At the same time a thermodynamic approach to neutron-proton capture was being discussed by physicists: neutron capture was interpretated as the reverse of deuteron photodissociation and detailed balance among neutrons, protons, deuterons, and radiation was invoked. This thermodynamic approach might underlie Fermi's early explanation of the great efficiency of slow neutrons. Fermi repeatedly used a thermodynamic approach that had been used in describing some of the physical properties of conductors by Richardson and had been influential in Fermi's youth.

  2. Attenuation of Reactor Gamma Radiation and Fast Neutrons Through Large Single-Crystal Materials

    International Nuclear Information System (INIS)

    Adib, M.

    2009-01-01

    A generalized formula is given which, for neutron energies in the range 10-4< E< 10 eV and gamma rays with average energy 2 MeV , permits calculation of the transmission properties of several single crystal materials important for neutron scattering instrumentation. A computer program Filter was developed which permits the calculation of attenuation of gamma radiation, nuclear capture, thermal diffuse and Bragg-scattering cross-sections as a function of materials constants, temperature and neutron energy. The applicability of the deduced formula along with the code checked from the obtained agreement between the calculated and experimental neutron transmission through various single-crystals A feasibility study for use of Si, Ge, Pb, Bi and sapphire is detailed in terms of optimum crystal thickness, mosaic spread and cutting plane for efficient transmission of thermal reactor neutrons and for rejection of the accompanying fast neutrons and gamma rays.

  3. Measurement of neutron radiation exposure of commercial airline pilots using bubble detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, B.J.; Kosierb, R. (Royal Military College of Canada, Kingston, Ontario (Canada). Dept. of Chemistry and Chemical Engineering); Cousins, T. (Defense Research Establishment Ottawa, Ontario (Canada). Space Systems and Technology Section); Hudson, D.F. (Air Canada Flight Operations, Vancouver, British Columbia (Canada)); Guery, G. (Air France-Direction des Operations Aeriennes, Roissy Charles de Gaulle (France))

    1994-06-01

    Neutron bubble detectors have been used over a 1-yr period by commercial airline pilots from Air Canada and Air France to measure the high-altitude neutron radiation exposure produced by galactic cosmic rays. The present work yielded measurements of the neutron flux of 1.0 to 4.6 n/cm[sup 2][center dot]s, and the neutron dose equivalent rates of 1.7 to 7.7 [mu]S[nu]/h. These measurements are in agreement with previous studies using high-altitude aircraft and conventional neutron instrumentation. The total dose equivalents for the Air Canada flights are also consistent with predictions of the CARI code. Considering that the neutron component contributes [approximately] 50% of the total dose equivalent, this study indicates that the annual dose for the air crew member would exceed the new recommendations of the International Commission on Radiological Protection (ICRP-60) for the general public.

  4. Measurement of neutron radiation exposure of commercial airline pilots using bubble detectors

    International Nuclear Information System (INIS)

    Lewis, B.J.; Kosierb, R.; Guery, G.

    1994-01-01

    Neutron bubble detectors have been used over a 1-yr period by commercial airline pilots from Air Canada and Air France to measure the high-altitude neutron radiation exposure produced by galactic cosmic rays. The present work yielded measurements of the neutron flux of 1.0 to 4.6 n/cm 2 ·s, and the neutron dose equivalent rates of 1.7 to 7.7 μSν/h. These measurements are in agreement with previous studies using high-altitude aircraft and conventional neutron instrumentation. The total dose equivalents for the Air Canada flights are also consistent with predictions of the CARI code. Considering that the neutron component contributes ∼ 50% of the total dose equivalent, this study indicates that the annual dose for the air crew member would exceed the new recommendations of the International Commission on Radiological Protection (ICRP-60) for the general public

  5. ANITA-2000 activation code package - updating of the decay data libraries and validation on the experimental data of the 14 MeV Frascati Neutron Generator

    Directory of Open Access Journals (Sweden)

    Frisoni Manuela

    2016-01-01

    Full Text Available ANITA-2000 is a code package for the activation characterization of materials exposed to neutron irradiation released by ENEA to OECD-NEADB and ORNL-RSICC. The main component of the package is the activation code ANITA-4M that computes the radioactive inventory of a material exposed to neutron irradiation. The code requires the decay data library (file fl1 containing the quantities describing the decay properties of the unstable nuclides and the library (file fl2 containing the gamma ray spectra emitted by the radioactive nuclei. The fl1 and fl2 files of the ANITA-2000 code package, originally based on the evaluated nuclear data library FENDL/D-2.0, were recently updated on the basis of the JEFF-3.1.1 Radioactive Decay Data Library. This paper presents the results of the validation of the new fl1 decay data library through the comparison of the ANITA-4M calculated values with the measured electron and photon decay heats and activities of fusion material samples irradiated at the 14 MeV Frascati Neutron Generator (FNG of the NEA-Frascati Research Centre. Twelve material samples were considered, namely: Mo, Cu, Hf, Mg, Ni, Cd, Sn, Re, Ti, W, Ag and Al. The ratios between calculated and experimental values (C/E are shown and discussed in this paper.

  6. Proceedings of the 5. Symposium on neutron dosimetry. Radiation protection aspects

    International Nuclear Information System (INIS)

    Schraube, H.; Burger, G.; Booz, J.

    1985-01-01

    Proceedings of the fifth symposium on neutron dosimetry, organized at Neuherberg, 17-21 September 1984, by the Commission of the European Communities and the GSF Neuherberg, with the co-sponsorship of the US Department of Energy, Office of Health and Environmental Research. The proceedings deal with research on concepts, instruments and methods in radiological protection for neutrons and mixed neutron-gamma fields, including the generation, collection and evaluation of new dosimetric data, the derivation of relevant radiation protection quantities, and the harmonization of experimental methods and instrumentation by intercomparison programmes. Besides radiation protection monitoring, the proceedings also report on the improvement of neutron beam dosimetry in the fields of radiobiology and radiation therapy

  7. Device for characterization of fissile materials comprising at least a neutron detector embedded inside a scintillator for gamma radiation detection

    International Nuclear Information System (INIS)

    Bernard, P.; Dherbey, J.R.; Bosser, R.; Berne, R.

    1989-01-01

    Fissile materials, for instance in radioactive wastes, are characterized by measurement of prompt and delayed neutrons and gamma radiation from induced fission by a neutron source. Gamma radiation is detected with a scintillation detector associated to a photomultiplier, the scintillation material is at the same time a moderator for thermalization of fast neutrons emitted by the neutron source and also of neutrons from spontaneous fission, (α, n) reactions and neutrons from induced fission in the fissile material. Preferentially the moderator is made of Altustipe (Plexiglas with anthracene as additive) [fr

  8. Evidence for a narrow massive state in the radiative decays of the Upsilon

    International Nuclear Information System (INIS)

    Crystal Ball Collaboration.

    1984-07-01

    Evidence is presented for a state, which we call zeta, with a mass M = (8322 +- 8 +- 24) MeV and a line width GAMMA < 80 MeV (90% confidence level) obtained using the Crystal Ball (NaI(Tl) detector at DORIS II. Radiative transitions to this state are observed from about 100,000 UPSILON(1S) decays in two independent sets of data: one in which zeta → multiple hadrons, and one which is strongly biased towards zeta → 2 low multiplicity jets. The branching ratio to this state from the UPSILON(1S) is of order 0.5%

  9. The contribution of the J/{psi} resonance to the radiative B decays

    Energy Technology Data Exchange (ETDEWEB)

    Soares, J M

    1995-03-01

    The radiative decays of the B mesons may have a significant contribution from the transition b {yields} sJ/{psi} followed by the J/{psi}-photon conversion. The size of this contribution is re-analysed in the light of a phenomenological model for the weak bsJ/{psi} vertex, and a modified J/{psi}-photon interaction that is manifestly gauge invariant. Predictions for both inclusive and exclusive cases are obtained but large uncertainties still remain. (author). 27 refs., 2 tabs., 2 figs.

  10. Transition probabilities and radiative decay constants of the excited levels of Ne

    International Nuclear Information System (INIS)

    Wosinski, L.

    1981-01-01

    Transition probabilities for eight optical transitions between the 3p and 3d neon levels have been measured by the ''plasma transparency method''. The transitions probabilities are placed on an absolute scale by use of the recently reported values for the 4p→3s transitions. The measurements of induced changes in populations allowed the determination of the ratios of the radiative decay constants for the 4p and 3d levels. The experimental results are compared with the theoretically calculated transitions probabilities of Murphy and Lilly. (author)

  11. Detection of gamma-neutron radiation by solid-state scintillation detectors. Detection of gamma-neutron radiation by novel solid-state scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ryzhikov, V.; Grinyov, B.; Piven, L.; Onyshchenko, G.; Sidletskiy, O. [Institute for Scintillation Materials of the NAS of Ukraine, Kharkov, (Ukraine); Naydenov, S. [Institute for Single Crystals of the National Academy of Sciences of Ukraine, Kharkov, (Ukraine); Pochet, T. [DETEC-Europe, Vannes (France); Smith, C. [Naval Postgraduate School, Monterey, CA (United States)

    2015-07-01

    It is known that solid-state scintillators can be used for detection of both gamma radiation and neutron flux. In the past, neutron detection efficiencies of such solid-state scintillators did not exceed 5-7%. At the same time it is known that the detection efficiency of the gamma-neutron radiation characteristic of nuclear fissionable materials is by an order of magnitude higher than the efficiency of detection of neutron fluxes alone. Thus, an important objective is the creation of detection systems that are both highly efficient in gamma-neutron detection and also capable of exhibiting high gamma suppression for use in the role of detection of neutron radiation. In this work, we present the results of our experimental and theoretical studies on the detection efficiency of fast neutrons from a {sup 239}Pu-Be source by the heavy oxide scintillators BGO, GSO, CWO and ZWO, as well as ZnSe(Te, O). The most probable mechanism of fast neutron interaction with nuclei of heavy oxide scintillators is the inelastic scattering (n, n'γ) reaction. In our work, fast neutron detection efficiencies were determined by the method of internal counting of gamma-quanta that emerge in the scintillator from (n, n''γ) reactions on scintillator nuclei with the resulting gamma energies of ∼20-300 keV. The measured efficiency of neutron detection for the scintillation crystals we considered was ∼40-50 %. The present work included a detailed analysis of detection efficiency as a function of detector and area of the working surface, as well as a search for new ways to create larger-sized detectors of lower cost. As a result of our studies, we have found an unusual dependence of fast neutron detection efficiency upon thickness of the oxide scintillators. An explanation for this anomaly may involve the competition of two factors that accompany inelastic scattering on the heavy atomic nuclei. The transformation of the energy spectrum of neutrons involved in the (n, n

  12. Total β-decay energies of neutron-rich zinc isotopes, A=75-80

    International Nuclear Information System (INIS)

    Lund, E.; Aleklett, K.; Fogelberg, B.; Sangariyavanish, A.

    1984-01-01

    The present investigation involves improved measurements of the Qsub(β)-values of 75-78 Zn and determinations of the total decay energies of sup(79,80)Zn which are not reported in the literature before. Also 81 Zn was detected but at the time for the experiment the ion-source was not efficient enough to yield sufficient activity for an accurate Qsub(β)-determination. (orig./HSI)

  13. The potential use of synthetic profiles of thermal neutrons decay time

    International Nuclear Information System (INIS)

    Tinoco, Franciso Lopes.

    1994-01-01

    The Time Lapse Technique used for monitoring the water and gas movement in a reservoir needs a PNC - Pulsed Neutron Capture Log - base log to be matched. However, few wells have this base log run in unchanged water saturation conditions. This paper presents two alternatives to be used a a base log: a synthetic PNC log and the initial gamma ray log. Some examples are presented to illustrate these techniques. (author). 1 ref., 6 figs., 2 tabs

  14. Efigie: a computer program for calculating end-isotope accumulation by neutron irradiation and radioactive decay

    International Nuclear Information System (INIS)

    Ropero, M.

    1978-01-01

    Efigie is a program written in Fortran V which can calculate the concentration of radionuclides produced by neutron irradiation of a target made of either a single isotope or several isotopes. The program includes optimization criteria that can be applied when the goal is the production of a single nuclide. The effect of a cooling time before chemical processing of the target is also accounted for.(author) [es

  15. Decay constants for pulsed monoenergetic neutron systems with quadratically anisotropic scattering

    International Nuclear Information System (INIS)

    Sjoestrand, N.G.

    1977-06-01

    The eigenvalues of the time-dependent transport equation for monoenergetic neutrons have been studied numerically for various combinations of linearly and quadratically anisotropic scattering assuming a space dependence of e β . The results, presented in the form of tables and graphs, show that quadratic anisotropy leads to a more complicated eigenvalue spectrum. However, no drastic changes occur in comparison to purely linear anistropy.(author)

  16. Determination of the ion thermal diffusivity from neutron emission profiles in decay

    Energy Technology Data Exchange (ETDEWEB)

    Sasao, M. (National Inst. for Fusion Science, Nagoya (Japan)); Adams, J.M. (AEA Industrial Technology, Harwell (United Kingdom)); Conroy, S.; Jarvis, O.N.; Marcus, F.B.; Sadler, G.; Belle, P. van (Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking)

    1994-01-01

    Spatial profiles of the neutron emission from deuterium plasmas are routinely obtained at the Joint European Torus (JET) using the line-integrated signals measured with a multichannel instrument. It is shown that the manner in which these profiles relax following the termination of strong heating with neutral beam injection (NBI) permits the local thermal diffusivity ([chi][sub i]) to be obtained with an accuracy of about 20%. (author).

  17. Determination of the ion thermal diffusivity from neutron emission profiles in decay

    International Nuclear Information System (INIS)

    Sasao, M.; Adams, J.M.; Conroy, S.; Jarvis, O.N.; Marcus, F.B.; Sadler, G.; Belle, P. van

    1994-01-01

    Spatial profiles of the neutron emission from deuterium plasmas are routinely obtained at the Joint European Torus (JET) using the line-integrated signals measured with a multichannel instrument. It is shown that the manner in which these profiles relax following the termination of strong heating with neutral beam injection (NBI) permits the local thermal diffusivity (χ i ) to be obtained with an accuracy of about 20%. (author)

  18. Laser-assisted decay and optical spectroscopy studies of neutron-deficient thallium isotopes

    CERN Document Server

    Van Beveren, Céline; Huyse, Mark

    The neutron-deficient thallium isotopes with one proton less than the Z = 82 shell closure, are situated in an interesting region of the nuclear chart, notorious for intruder states and shape coexistence. Shape coexistence is the remarkable phenomenon in which two or more distinct types of deformation occur at low energy in the same atomic nucleus. Shape coexistence has been studied intensively, experimentally as well as theoretically in different nuclei in the light-lead region and the isomerism in the thallium isotopes was among the first indications of this phenomenon. Different shapes, whose structure has been linked to specific proton orbitals above and below the Z = 82 shell closure, are present at low energy in the neutron-deficient odd-mass thallium nuclei. In the odd-odd nuclei, the coupling of an unpaired proton and unpaired neutron gives rise to multiplets of low-lying states from which some can be isomeric. Since thallium has one proton missing in the major proton shell, and when approaching neutr...

  19. Microscopic integral cross section measurements in the Be(d,n) neutron spectrum for applications in neutron dosimetry, radiation damage and the production of long-lived radionuclides

    International Nuclear Information System (INIS)

    Smith, D.L.; Meadows, J.W.; Greenwood, L.R.

    1990-01-01

    Integral neutron-reaction cross sections have been measured, relative to the U-238 neutron fission cross-section standard, for 27 reactions which are of contemporary interest in various nuclear applications (e.g., fast-neutron dosimetry, neutron radiation damage and the production of long-lived activities which affect nuclear waste disposal). The neutron radiation field employed in this study was produced by bombarding a thick Be-metal target with 7-MeV deuterons from an accelerator. The experimental results are reported along with detailed information on the associated measurement uncertainties and their correlations. These data are also compared with corresponding calculated values, based on contemporary knowledge of the differential cross sections and of the Be(d,n) neutron spectrum. Some conclusions are reached on the utility of this procedure for neutron-reaction data testing

  20. Biological effects of neutron radiation and their implications for the nuclear power industry

    International Nuclear Information System (INIS)

    Dennis, J.A.

    1983-01-01

    Stimulated biophysical theories of the action of radiation on the cells of mammalian tissues, research on the effects of neutrons has been interpreted as implying that neutron radiation is about 60 times more effective than gamma radiation for the induction of tumours in rodents and for shortening their lives. This contrasts with the assumption made for protection purposes that it is only about ten times as effective. However, the same experiments can be interpreted also as implying that gamma radiation at the dose rates encountered in the workplace is five to ten times less effective than is generally assumed. Taken together these observations suggest that the real risks to humans from neutrons are comparable with the assumed risks from X- and gamma radiation. Further data are required to confirm these observations and their interpretation, and in the short term there is no need to change the current practices of radiological protection as regards neutron radiation. Nevertheless, it might be wise for long-term planning purposes to anticipate a reduction in the maximum permissible fluences of neutrons by a factor of about 3. (author)

  1. Naturally large radiative lepton flavor violating Higgs decay mediated by lepton-flavored dark matter

    International Nuclear Information System (INIS)

    Baek, Seungwon; Kang, Zhaofeng

    2016-01-01

    In the standard model (SM), lepton flavor violating (LFV) Higgs decay is absent at renormalizable level and thus it is a good probe to new physics. In this article we study a type of new physics that could lead to large LFV Higgs decay, i.e., a lepton-flavored dark matter (DM) model which is specified by a Majorana DM and scalar lepton mediators. Different from other similar models with similar setup, we introduce both left-handed and right-handed scalar leptons. They allow large LFV Higgs decay and thus may explain the tentative Br(h→τμ)∼1% experimental results from the LHC. In particular, we find that the stringent bound from τ→μγ can be naturally evaded. One reason, among others, is a large chirality violation in the mediator sector. Aspects of relic density and especially radiative direct detection of the leptonic DM are also investigated, stressing the difference from previous lepton-flavored DM models.

  2. Simulation of Thermal, Neutronic and Radiation Characteristics in Spent Nuclear Fuel and Radwaste Facilities

    International Nuclear Information System (INIS)

    Poskas, P.; Bartkus, G.

    1999-01-01

    The overview of the activities in the Division of Thermo hydro-mechanics related with the assessment of thermal, neutronic and radiation characteristics in spent nuclear fuel and radwaste facilities are performed. Also some new data about radiation characteristics of the RBMK-1500 spent nuclear fuel are presented. (author)

  3. Analysis of unstable chromosome alterations frequency induced by neutron-gamma mixed field radiation

    International Nuclear Information System (INIS)

    Souza, Priscilla L.G.; Brandao, Jose Odinilson de C.; Vale, Carlos H.F.P.; Santos, Joelan A.L.; Vilela, Eudice C.; Lima, Fabiana F.; Calixto, Merilane S.; Santos, Neide

    2009-01-01

    Nowadays monitoring chromosome alterations in peripheral blood lymphocytes have been used to access the radiation absorbed dose in individuals exposed accidental or occupationally to gamma radiation. However there are not many studies based on the effects of mixed field neutron-gamma. The radiobiology of neutrons has great importance because in nuclear factories worldwide there are several hundred thousand individuals monitored as potentially receiving doses of neutron. In this paper it was observed the frequencies of unstable chromosome alterations induced by a gamma-neutron mixed field. Blood was obtained from one healthy donor and exposed to mixed field neutron-gamma sources 241 AmBe (20 Ci) at the Neutron Calibration Laboratory (NCL-CRCN/NE-PE-Brazil). The chromosomes were observed at metaphase, following colcemid accumulation and 1000 well-spread metaphases were analyzed for the presence of chromosome alterations by two experienced scorers. The results suggest that there is the possibility of a directly proportional relationship between absorbed dose of neutron-gamma mixed field radiation and the frequency of unstable chromosome alterations analyzed in this paper. (author)

  4. Analysis of unstable chromosome alterations frequency induced by neutron-gamma mixed field radiation

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Priscilla L.G.; Brandao, Jose Odinilson de C.; Vale, Carlos H.F.P.; Santos, Joelan A.L.; Vilela, Eudice C.; Lima, Fabiana F. [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)], e-mail: psouza@cnen.gov.br, e-mail: jodinilson@cnen.gov.br; Calixto, Merilane S.; Santos, Neide [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Genetica

    2009-07-01

    Nowadays monitoring chromosome alterations in peripheral blood lymphocytes have been used to access the radiation absorbed dose in individuals exposed accidental or occupationally to gamma radiation. However there are not many studies based on the effects of mixed field neutron-gamma. The radiobiology of neutrons has great importance because in nuclear factories worldwide there are several hundred thousand individuals monitored as potentially receiving doses of neutron. In this paper it was observed the frequencies of unstable chromosome alterations induced by a gamma-neutron mixed field. Blood was obtained from one healthy donor and exposed to mixed field neutron-gamma sources {sup 241}AmBe (20 Ci) at the Neutron Calibration Laboratory (NCL-CRCN/NE-PE-Brazil). The chromosomes were observed at metaphase, following colcemid accumulation and 1000 well-spread metaphases were analyzed for the presence of chromosome alterations by two experienced scorers. The results suggest that there is the possibility of a directly proportional relationship between absorbed dose of neutron-gamma mixed field radiation and the frequency of unstable chromosome alterations analyzed in this paper. (author)

  5. Influence of non-LTE radiation ablation on imploding neutron yield

    International Nuclear Information System (INIS)

    Sheng Jiatian; Li Yunsheng; Gao Yaomin; Li Meng; Feng Tinggui; Zhang Lifa; Zeng Xiancai; Mou Wenyong; Feng Jie; Chen Jiabin

    2005-01-01

    The process of radiative ablation and neutron yields of DD-capsule with CH shell implosion driven by Plank spectrum and nonequilibrium spectrum radiation fields was numerically studied using 1-D RDMG code of multigroup-nonequilibrium radiation hydrodynamics. The simulation results were compared with the experimental results. The results of the simulation show that the nonequilibrium of energy spectrum distribution of the hohlraum radiation source, especially the M-band of it, will preheat DD in the capsule obviously, decrease the compressing ratio, electron and ion temperatures of DD gas, and therefore decrease the neutron yields markedly. The simulation results also show that the law of decreasing of neutron yields with increasing of the CH-sell thickness is in agreement with the experiment basically. (authors)

  6. Measurement of Inclusive Radiative B -Meson Decay B -> X_s gamma

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, V.E.; /SLAC /Stanford U., Appl. Phys. Dept.

    2006-01-06

    Radiative decays of the B meson, B {yields} X{sub s}{gamma}, proceed via virtual flavor changing neutral current processes that are sensitive to contributions from high mass scales, either within the Standard Model of electroweak interactions or beyond. In the Standard Model, these transitions are sensitive to the weak interactions of the top quark, and relatively robust predictions of the inclusive decay rate exist. Significant deviation from these predictions could be interpreted as indications for processes not included in the minimal Standard Model, like interactions of charged Higgs or SUSY particles. The analysis of the inclusive photon spectrum from B {yields} X{sub s}{gamma} decays is rather challenging due to high backgrounds from photons emitted in the decay of mesons in B decays as well as e{sup +}e{sup -} annihilation to low mass quark and lepton pairs. Based on 88.5 million B{bar B} events collected by the BABAR detector, the photon spectrum above 1.9 GeV is presented. By comparison of the first and second moments of the photon spectrum with QCD predictions (calculated in the kinetic scheme), QCD parameters describing the bound state of the b quark in the B meson are extracted: m{sub b} = (4.45 {+-} 0.16) GeV/c{sup 2}; {mu}{sub {pi}}{sup 2} = (0.65 {+-} 0.29) GeV{sup 2}. These parameters are useful input to non-perturbative QCD corrections to the semileptonic B decay rate and the determination of the CKM parameter |V{sub ub}|. Based on these parameters and heavy quark expansion, the full branching fraction is obtained as: {Beta}(B {yields} X{sub s}{gamma}){sup E{sub {gamma}}>1.6 GeV} = (4.05 {+-} 0.32(stat) {+-} 0.38(syst) {+-} 0.29(model)) x 10{sup -4}. This result is in good agreement with previous measurements, the statistical and systematic errors are comparable. It is also in good agreement with the theoretical Standard Model predictions, and thus within the present errors there is no indication of any interactions not accounted for in the

  7. Neutron spectra measurements and neutron flux monitoring for radiation damage purposes

    International Nuclear Information System (INIS)

    Osmera, B.; Petr, J.; Racek, J.; Rumler, C.; Turzik, Z.; Franc, L.; Holman, M.; Hogel, J.; Kovarik, K.; Marik, P.; Vespalec, R.; Albert, D.; Hansen, V.; Vogel, W.

    1979-09-01

    Neutron spectra were measured for the TR-0, WWR-S and SR-0 experimental reactors using the recoil proton method, 6 Li spectrometry, scintillation spectrometry and activation detectors in a variety of conditions. Neutron fluence was also measured and calculated. (M.S.)

  8. Determination of the radiative decay width of the positive K*+(890) meson

    International Nuclear Information System (INIS)

    Chandlee, C.D.

    1983-01-01

    A systematic study of the coherent excitation of high energy pions and kaons by nuclear targets has been completed at Fermilab (Experiment 272) with the intent of extracting the radiative decay widths of the various vector and tensor mesons. This work was initiated to furnish experimental results for comparison with theoretical predictions based on unitary symmetry schemes, quark models, and vector dominance models with the hope of shedding light on the structure of the quark-antiquark system. The work presented here deals with data collected during the second running period of E272 on the excitation of incident 200 GeV/c K + by copper and lead targets for the purpose of precisely determining the radiative width from the transition K* + (890) → K + γ. The experiment was performed in the MIE secondary beam line of the Meson Lab utilizing an enhanced, Cherenkov tagged, positive kaon beam, a forward charged particle spectrometer consisting of drift and proportional wire chambers, and a liquid argon colorimeter for photon detection. A Primakoff type analysis of excitation in the nuclear Coulomb field including a strong contribution to the coherent production process from isoscalar exchange was applied to data for both the K + π 0 and K/sub S/ 0 π + decay modes of the K* +

  9. Fourier Transform Infrared Radiation Spectroscopy Applied for Wood Rot Decay and Mould Fungi Growth Detection

    Directory of Open Access Journals (Sweden)

    Bjørn Petter Jelle

    2012-01-01

    Full Text Available Material characterization may be carried out by the attenuated total reflectance (ATR Fourier transform infrared (FTIR radiation spectroscopical technique, which represents a powerful experimental tool. The ATR technique may be applied on both solid state materials, liquids, and gases with none or only minor sample preparations, also including materials which are nontransparent to IR radiation. This facilitation is made possible by pressing the sample directly onto various crystals, for example, diamond, with high refractive indices, in a special reflectance setup. Thus ATR saves time and enables the study of materials in a pristine condition, that is, the comprehensive sample preparation by pressing thin KBr pellets in traditional FTIR transmittance spectroscopy is hence avoided. Materials and their ageing processes, both ageing by natural and accelerated climate exposure, decomposition and formation of chemical bonds and products, may be studied in an ATR-FTIR analysis. In this work, the ATR-FTIR technique is utilized to detect wood rot decay and mould fungi growth on various building material substrates. An experimental challenge and aim is to be able to detect the wood rot decay and mould fungi growth at early stages when it is barely visible to the naked eye. Another goal is to be able to distinguish between various species of fungi and wood rot.

  10. Towards radiation hard converter material for SiC-based fast neutron detectors

    Science.gov (United States)

    Tripathi, S.; Upadhyay, C.; Nagaraj, C. P.; Venkatesan, A.; Devan, K.

    2018-05-01

    In the present work, Geant4 Monte-Carlo simulations have been carried out to study the neutron detection efficiency of the various neutron to other charge particle (recoil proton) converter materials. The converter material is placed over Silicon Carbide (SiC) in Fast Neutron detectors (FNDs) to achieve higher neutron detection efficiency as compared to bare SiC FNDs. Hydrogenous converter material such as High-Density Polyethylene (HDPE) is preferred over other converter materials due to the virtue of its high elastic scattering reaction cross-section for fast neutron detection at room temperature. Upon interaction with fast neutrons, hydrogenous converter material generates recoil protons which liberate e-hole pairs in the active region of SiC detector to provide a detector signal. The neutron detection efficiency offered by HDPE converter is compared with several other hydrogenous materials viz., 1) Lithium Hydride (LiH), 2) Perylene, 3) PTCDA . It is found that, HDPE, though providing highest efficiency among various studied materials, cannot withstand high temperature and harsh radiation environment. On the other hand, perylene and PTCDA can sustain harsh environments, but yields low efficiency. The analysis carried out reveals that LiH is a better material for neutron to other charge particle conversion with competent efficiency and desired radiation hardness. Further, the thickness of LiH has also been optimized for various mono-energetic neutron beams and Am-Be neutron source generating a neutron fluence of 109 neutrons/cm2. The optimized thickness of LiH converter for fast neutron detection is found to be ~ 500 μm. However, the estimated efficiency for fast neutron detection is only 0.1%, which is deemed to be inadequate for reliable detection of neutrons. A sensitivity study has also been done investigating the gamma background effect on the neutron detection efficiency for various energy threshold of Low-Level Discriminator (LLD). The detection

  11. Disordered nuclear pasta, magnetic field decay, and crust cooling in neutron stars

    OpenAIRE

    Horowitz, C. J.; Berry, D. K.; Briggs, C. M.; Caplan, M. E.; Cumming, A.; Schneider, A. S.

    2014-01-01

    Nuclear pasta, with non-spherical shapes, is expected near the base of the crust in neutron stars. Large scale molecular dynamics simulations of pasta show long lived topological defects that could increase electron scattering and reduce both the thermal and electrical conductivities. We model a possible low conductivity pasta layer by increasing an impurity parameter Q_{imp}. Predictions of light curves for the low mass X-ray binary MXB 1659-29, assuming a large Q_{imp}, find continued late ...

  12. Decay of a three-quasiparticle isomer in the neutron-rich nucleus 183Ta

    Directory of Open Access Journals (Sweden)

    Zhu S.

    2012-10-01

    Full Text Available Excited states in neutron-rich tantalum isotopes have been studied with deep-inelastic reactions using 136Xe ions incident on a 186W target. New transitions observed below the τ=1.3 μs isomer in 183Ta have enabled the establishment of its energy and put limits on the spin and parity. On the basis of the reduced hindrances for the depopulating transitions, a 3-quasiparticle configuration of ν1/2−[510]11/2+[615] ⊗ π9/2−[514] is suggested.

  13. Beam plug replacement and alignment under high radiation conditions for cold neutron facilities at Hanaro

    International Nuclear Information System (INIS)

    Yeong-Garp, Cho; Jin-Won, Shin; Jung-Hee, Lee; Jeong-Soo, Ryu

    2010-01-01

    Full text : The HANARO, an open-tank-in-pool type research reactor of a 30 MWth power in Korea, has been operating for 15 years since its initial criticality in February 1995. The beam port assigned for the cold neutron at HANARO had been used for an 8-m SANS without neutron guides until it was replaced by a cold neutron guide system in 2008. It was developed a cold neutron guide system for the delivery of cold neutrons from the cold neutron source in the reactor to the neutron scattering instruments in the guide hall. Since the HANARO has been operated from 1995, it was a big challenge to replace the existing plug and shutter with the new facilities under high radiation conditions. When the old plug was removed from the beam port in 2008, the radiation level was 230 mSv/hr at the end of beam port. In addition to that, there were more difficult situations such as the poor as-built dimensions of the beam port, limited work space and time constraint due to other constructions in parallel in the reactor hall. Before the removal of the old plug the level of the radiation was measured coming out through a small hole of the plug to estimate the radiation level during the removal of the old plug and installation of a new plug. Based on the measurement and analysis results, special tools and various shielding facilities were developed for the removal of old in-pile plug and the installation of the new in-pile plug assembly safely. In 2008, the old plug and shutter were successfully replaced by the new plug and shutter as shown in this article with a minimum exposure to the workers. A laser tracker system was also one of the main factors in our successful installation and alignment under high radiation conditions and limited work space. The laser tracker was used to measure and align all the mechanical facilities and the neutron guides with a minimum radiation exposure to workers. The alignment of all the guides and accessories were possible during reactor operation because

  14. Measurement of beta decay periods for Fe-Ni neutrons rich isotopes

    International Nuclear Information System (INIS)

    Czajkowski, S.

    1992-01-01

    Thermal fission of 239 Pu was used to produce 68,69 Co and 68 Fe isotopes, the lightest ones ever observed in thermal fission, at the ILL high-flux reactor, in Grenoble. Separated with the Lohengrin recoil spectrometer, then identified by means of a Δ E-E ionization chamber, fragments were implanted in a set of Si-detectors, where β-particles were detected too. The fission yields were determined, and the beta-decay half-lives were extracted from delayed coincidence analysis between ion implantation and the subsequent beta detection: They were found to be 0.27±0.05s, 0.18±0.10s, and 0.10±0.06s respectively for 69 Co, 68 Co, and 68 Fe. This method was adapted to a new experimental configuration: 65 Fe isotopes were produced from 86 Kr projectile fragmentation at 500 MeV/u on a Be target. Selected ions were separated with the fragment separator FRS at GSI (Darmstadt), tuned in the monoenergetic mode. Fragments were identified by ΔE-ToF, slowed down, and then implanted in two rows of PIN-diodes that provided an additional range selection. The half-life were determined from the analysis of the decay chain Fe-Co-Ni: it was found 0.4±0.2s. Production rates obtained with the two methods are compared at the end of this work

  15. Fast neutron radiation inactivation of Bacillus subtilis: Absorbed dose determination

    International Nuclear Information System (INIS)

    Song Lingli; Zheng Chun; Ai Zihui; Li Junjie; Dai Shaofeng

    2011-01-01

    In this paper, fast neutron inactivation effects of Bacillus subtilis were investigated with fission fast neutrons from CFBR-II reactor of INPC (Institute of Nuclear Physics and Chemistry) and mono-energetic neutrons from the Van de Graaff accelerator at Peking University. The method for determining the absorbed dose in the Bacillus subtilis suspension contained in test tubes is introduced. The absorbed dose, on account of its dependence on the volume and the form of confined state, was determined by combined experiments and Monte Carlo method. Using the calculation results of absorbed dose, the fast neutron inactivation effects on Bacillus subtilis were studied. The survival rates and absorbed dose curve was constructed. (authors)

  16. Addendum to ''Radiative corrections to the Dalitz plot of semileptonic decays of neutral baryons with light or charm quarks''

    International Nuclear Information System (INIS)

    Martinez, A.; Tun, D.M.; Garcia, A.; Sanchez-Colon, G.

    1994-01-01

    We show that the radiative corrections containing terms up to order αq/πM 1 for unpolarized semileptonic decays of baryons with positron emission can be obtained by simply reversing the sign of the axial-vector form factors in the corresponding final expressions of such decays with electron emission. This rule is valid regardless of the final kinematical variables chosen and of the particular Lorentz frame in which the final results are required

  17. Long-term prognosis of maxillary sinus malignant tumor patients treated by fast neutron radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kishi, Hirohisa; Numata, Tsutomu; Yuza, Jun; Suzuki, Haruhiko; Konno, Akiyoshi [Chiba Univ. (Japan). School of Medicine; Miyamoto, Tadaaki

    1995-03-01

    From 1976 through 1990, 19 patients with maxillary sinus malignant tumor were treated with combination therapy consisting of maxillectomy and radiation of fast neutron. Fast neutron radiotherapy was performed at National Institute of Radiological Sciences. Eight patients had adenoid cystic carcinomas, three patients squamous cell carcinomas, one patient a carcinoma in pleomorphic adenoma, four patients fibrosarcomas, one patient osteosarcoma, one patient chondrosarcoma and one patient rhabdomyosarcoma. Fast neutron therapy after/before surgery was effective in fresh cases with T2-3N0M0 adenoid cystic carcinomas and sarcomas (except for fibrosarcoma). Nine patients were alive more than three years after treatment. And serious complications of fast neutron radiation therapy appeared in six of these nine patients. Visual impairment of opposite side occurred in four patients. Bone necrosis occured in one patient and brain dysfunction in one patient. (author).

  18. Long-term prognosis of maxillary sinus malignant tumor patients treated by fast neutron radiation therapy

    International Nuclear Information System (INIS)

    Kishi, Hirohisa; Numata, Tsutomu; Yuza, Jun; Suzuki, Haruhiko; Konno, Akiyoshi; Miyamoto, Tadaaki.

    1995-01-01

    From 1976 through 1990, 19 patients with maxillary sinus malignant tumor were treated with combination therapy consisting of maxillectomy and radiation of fast neutron. Fast neutron radiotherapy was performed at National Institute of Radiological Sciences. Eight patients had adenoid cystic carcinomas, three patients squamous cell carcinomas, one patient a carcinoma in pleomorphic adenoma, four patients fibrosarcomas, one patient osteosarcoma, one patient chondrosarcoma and one patient rhabdomyosarcoma. Fast neutron therapy after/before surgery was effective in fresh cases with T2-3N0M0 adenoid cystic carcinomas and sarcomas (except for fibrosarcoma). Nine patients were alive more than three years after treatment. And serious complications of fast neutron radiation therapy appeared in six of these nine patients. Visual impairment of opposite side occurred in four patients. Bone necrosis occured in one patient and brain dysfunction in one patient. (author)

  19. Biological effectiveness of pulsed and continuous neutron radiation for cells of yeast Saccharomyces

    International Nuclear Information System (INIS)

    Tsyb, T.S.; Komarova, E.V.; Potetnya, V.I.; Obaturov, G.M.

    2001-01-01

    Data are presented on biological effectiveness of fast neutrons generated by BR-10 reactor (dose rate up to 3.8 Gy/s) in comparison with neutrons of pulsed BARS-6 reactor (dose rate ∼6x10 6 Gy/s) for yeast Saccharomyces vini cells of a wild type Menri 139-B and radiosensitive Saccharomyces cerevisiae (rad52/rad52; rad54/rad54) mutants which are defective over different systems of DNA reparation. Value of relative biological efficiency (RBE) of continuous radiation for wild stam is from 3.5 up to 2.5 when survival level being 75-10 %, and RBE of pulsed neutron radiation is in the limits of 2.0-1.7 at the same levels. For mutant stam the value of RBE (1.4-1.6) of neutrons is constant at all survival levels and does not depend on dose rate [ru

  20. QCD non-perturbative study in radiative and pure-leptonic decays of Bc by wave function

    International Nuclear Information System (INIS)

    Guo Peng; Hou Zhaoyu; Zhi Haisu

    2012-01-01

    The radiative and pure-leptonic decays of B c mesons are of hadrons uncertainty in theoretical calculations. Using three types of the B c meson wave functions which describe the characteristics of the QCD non-perturbative and by controlling the parameters in them, the uncertainties of B c meson decay caused by the hadron decay model are studied in detail. The theoretical results show the branching ratios are (1.81981∼3.18961) × 10 -5 , which are sensitive to the type of wave functions. (authors)