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Sample records for 2h 3he 6li

  1. THE 2H(alpha, gamma6LI REACTION AT LUNA AND BIG BANG NUCLEOSYNTHETIS

    Directory of Open Access Journals (Sweden)

    Carlo Gustavino

    2013-12-01

    Full Text Available The 2H(α, γ6Li reaction is the leading process for the production of 6Li in standard Big Bang Nucleosynthesis. Recent observations of lithium abundance in metal-poor halo stars suggest that there might be a 6Li plateau, similar to the well-known Spite plateau of 7Li. This calls for a re-investigation of the standard production channel for 6Li. As the 2H(α, γ6Li cross section drops steeply at low energy, it has never before been studied directly at Big Bang energies. For the first time the reaction has been studied directly at Big Bang energies at the LUNA accelerator. The preliminary data and their implications for Big Bang nucleosynthesis and the purported 6Li problem will be shown.

  2. High-energy break-up of 6Li as a tool to study the Big-Bang nucleosynthesis reaction 2H(alpha,gamma)6Li

    CERN Document Server

    Hammache, F; Typel, S; Galaviz, D; Sümmerer, K; Coc, A; Uhlig, F; Attallah, F; Caamano, M; Cortina, D; Geissel, H; Hellström, M; Iwasa, N; Kiener, J; Koczon, P; Kohlmeyer, B; Mohr, P; Schwab, E; Schwarz, K; Schümann, F; Senger, P; Sorlin, O; Tatischeff, V; Thibaud, J P; Vangioni, E; Wagner, A; Walus, W

    2010-01-01

    The recently claimed observations of non-negligible amounts of 6Li in old halo stars have renewed interest in the Big-Bang Nucleosynthesis (BBN) of 6Li. One important ingredient in the predicted BBN abundance of 6Li is the low-energy 2H(alpha,gamma)6Li cross section. Up to now, the only available experimental result for this cross section showed an almost constant astrophysical S-factor below 400 keV, contrary to theoretical expectations. We report on a new measurement of the 2H(alpha,gamma)6Li reaction using the break-up of 6Li at 150 A MeV. Even though we cannot separate experimentally the Coulomb contribution from the nuclear one, we find clear evidence for Coulomb-nuclear interference by analyzing the scattering-angular distributions. This is in-line with our theoretical description which indicates a drop of the S_24-factor at low energies as predicted also by most other models. Consequently, we find even lower upper limits for the calculated primordial 6Li abundance than before.

  3. Effects of t- and α-transfer on the spectroscopic information from the {sup 6}Li({sup 3}He,d){sup 7}Be reaction

    Energy Technology Data Exchange (ETDEWEB)

    Burtebayev, N., E-mail: nburtebayev@yandex.ru [Institute of Nuclear Physics of National Nuclear Center, 480082, Almaty, Ibragimova str. 1 (Kazakhstan); Burtebayeva, J.T.; Glushchenko, N.V.; Kerimkulov, Zh.K. [Institute of Nuclear Physics of National Nuclear Center, 480082, Almaty, Ibragimova str. 1 (Kazakhstan); Amar, A. [Al-Farabi Kazakh National University, 480078, Almaty, al-Farabi ave. 71 (Kazakhstan); Tanta University, Faculty of Science, Physics Department, Tanta (Egypt); Nassurlla, M. [Al-Farabi Kazakh National University, 480078, Almaty, al-Farabi ave. 71 (Kazakhstan); Sakuta, S.B. [National Research Center “Kurchatov Institute”, Kurchatov Sq. 1, 123182 Moscow (Russian Federation); Artemov, S.V.; Igamov, S.B.; Karakhodzhaev, A.A. [Institute of Nuclear Physics, Tashkent, Avliyo Ota str. 61 (Uzbekistan); Rusek, K. [Heavy Ion Laboratory of Warsaw University, ul. L. Pasteura 5A, PL-02-093 Warsaw (Poland); Kliczewski, S. [H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Cracow (Poland)

    2013-07-01

    Angular distributions of differential cross sections have been measured for elastic, inelastic scattering and the ({sup 3}He,d) reaction on {sup 6}Li nuclei at the E{sub lab}({sup 3}He)=34 MeV energy. The new and early obtained elastic scattering data at 34, 50, 60 and 72 MeV have been analyzed with Coupled Reaction Channels Method (CRC) taking into account triton transfer mechanism. The spectroscopic factors for t+{sup 3}He configuration of {sup 6}Li were extracted. Parameters for real part of potential have been also calculated microscopically with double folding model. The differential cross sections for proton stripping to the {sup 7}Be ground and first excited states have been analyzed by modified DWBA and CRC methods at 34 MeV. The effect of triton and α exchange on proton transfer reaction {sup 6}Li({sup 3}He,d){sup 7}Be for both ground and excited state is discussed. Spectroscopic factors and asymptotical normalization coefficients for p+{sup 6}Li configuration of {sup 7}Be have been obtained from the experimental data.

  4. Angular Distribution and Cross Section Measurement of the 6Li(3He,n8B Reaction at 5.8 MeV

    Directory of Open Access Journals (Sweden)

    Cinausero M.

    2014-03-01

    Full Text Available The reaction 6Li(3He,n8B was studied at Laboratori Nazionali di Legnaro in the framework of the EUROnu Design Study for a Beta Beam facility at CERN. The 8B production cross section was determined through neutron angular distribution by using the time-of-flight technique. Thanks to the high statistics achieved, the neutron angular distribution for the population of the 8B first excited state has been measured for the first time. Discrepancies with other available data sets for 8B ground state population are discussed and interpreted in the framework of DWBA calculations. Further measurements at beam energies above 10 MeV are needed to clarify the behaviour of the angular distribution

  5. The Astrophysical S-factor for the 2H(, )6Li Nuclear Reaction at Low-Energies

    Indian Academy of Sciences (India)

    H. Sadeghi; A. Moghadasi; M. Ghamary

    2014-12-01

    The alpha radiative capture reactions are the key to understand about primordial nucleosynthesis and the observed abundance of light nucleus in stars. The astrophysical S-factor for the process 2H(, )6Li has been calculated at the low-energies relevant to big-bang nucleosynthesis and in comparison with laboratory data. On the basis of the model, the alpha radiative capture process is studied by using the two-and three-body electromagnetic currents. The bound and resonance states of 6Li are calculated via an inverse process, deuteron- photodisintegration of a 6Li nucleus. In comparison with other theoretical approaches and available laboratory data, excellent agreement is achieved for the astrophysical S-factor of this process.

  6. Narrow structure in η-photoproducion off {sup 2}H and {sup 3}He

    Energy Technology Data Exchange (ETDEWEB)

    Witthauer, Lilian; Werthmueller, Dominik [Department of Physics, University of Basel (Switzerland); Collaboration: A2-Collaboration

    2013-07-01

    Large efforts have been made in the last years to investigate the complicated excitation spectrum of the nucleons. Especially η-Photoproduction has been studied by many collaborations. Experiments at CBELSA/TAPS and GRAAL revealed a bump-like structure in the quasi-free η-Photoproduction on the neutron, which is not seen on the proton (I. Jaegle et al., PRL 100 (2008), V.Kuznetsov et al., PLB 647 (2007)). To examine this structure high statistics experiments using the A2 detector setup with the Crystal Ball calorimeter and the TAPS detector at the electron acceleration facility MAMI have been carried out. To exclude any possibility that the structure could arise from nuclear effects, η-photoproduction in coincidence with recoil nucleons has been measured on two different targets, namely {sup 2}H and {sup 3}He. This talk gives an overview over the final results on quasi-free inclusive and exclusive η-Photoproduction off quasi-free protons and neutrons.

  7. First direct measurement of the 2H(α,γ)6Li cross section at big bang energies and the primordial lithium problem.

    Science.gov (United States)

    Anders, M; Trezzi, D; Menegazzo, R; Aliotta, M; Bellini, A; Bemmerer, D; Broggini, C; Caciolli, A; Corvisiero, P; Costantini, H; Davinson, T; Elekes, Z; Erhard, M; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Junker, M; Lemut, A; Marta, M; Mazzocchi, C; Prati, P; Rossi Alvarez, C; Scott, D A; Somorjai, E; Straniero, O; Szücs, T

    2014-07-25

    Recent observations of (6)Li in metal poor stars suggest a large production of this isotope during big bang nucleosynthesis (BBN). In standard BBN calculations, the (2)H(α,γ)(6)Li reaction dominates (6)Li production. This reaction has never been measured inside the BBN energy region because its cross section drops exponentially at low energy and because the electric dipole transition is strongly suppressed for the isoscalar particles (2)H and α at energies below the Coulomb barrier. Indirect measurements using the Coulomb dissociation of (6)Li only give upper limits owing to the dominance of nuclear breakup processes. Here, we report on the results of the first measurement of the (2)H(α,γ)(6)Li cross section at big bang energies. The experiment was performed deep underground at the LUNA 400 kV accelerator in Gran Sasso, Italy. The primordial (6)Li/(7)Li isotopic abundance ratio has been determined to be (1.5 ± 0.3) × 10(-5), from our experimental data and standard BBN theory. The much higher (6)Li/(7)Li values reported for halo stars will likely require a nonstandard physics explanation, as discussed in the literature.

  8. Adsorbed Layers of D2, H2, O2, and 3He on Graphite Studied by Neutron Scattering

    DEFF Research Database (Denmark)

    Nielsen, Mourits; McTague, J. P.; Ellenson, W. D.

    1977-01-01

    The phase diagrams of adsorbed monolayers of D2, H2, O2, and 3He on graphite have been measured by neutron diffraction. H2 and D2-layers have a registered √3 structure at low coverages, and at monolayer completion they have a dense triangular structure, which is incommensurate with the substrate....

  9. Signatures of the chiral two-pion exchange electromagnetic currents in the 2H and 3He photodisintegration reactions

    CERN Document Server

    Rozpedzik, D; Kolling, S; Epelbaum, E; Skibinski, R; Witala, H; Krebs, H

    2011-01-01

    The recently derived long-range two-pion exchange (TPE) contributions to the nuclear current operator which appear at next-to-leading order (NLO) of the chiral expansion are used to describe electromagnetic processes. We study their role in the photodisintegration of 2H and 3He and compare our predictions with experimental data. The bound and scattering states are calculated using five different parametrizations of the chiral next-to-next-to-leading order (N2LO) nucleon-nucleon (NN) potential which allows us to estimate the theoretical uncertainty at a given order in the chiral expansion. For some observables the results are very close to the predictions based on the AV18 NN potential and the current operator (partly) consistent with this force. In the most cases, the addition of long-range TPE currents improved the description of the experimental data.

  10. Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(alpha,gamma)6Li reaction at LUNA

    CERN Document Server

    Anders, M; Bellini, A; Aliotta, M; Bemmerer, D; Broggini, C; Caciolli, A; Costantini, H; Corvisiero, P; Davinson, T; Elekes, Z; Erhard, M; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Junker, M; Lemut, A; Marta, M; Mazzocchi, C; Menegazzo, R; Prati, P; Alvarez, C Rossi; Scott, D; Somorjai, E; Straniero, O; Szücs, T

    2013-01-01

    The production of the stable isotope Li-6 in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological Li-6 plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of Li-7 abundances and would point to a predominantly primordial origin of Li-6, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang Li-6 production must be revisited. The main production channel for Li-6 in the Big Bang is the 2H(alpha,gamma)6Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {\\alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the 2H(d,n)3He reaction....

  11. 6Li foil thermal neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Ianakiev, Kiril D [Los Alamos National Laboratory; Swinhoe, Martyn T [Los Alamos National Laboratory; Favalli, Andrea [Los Alamos National Laboratory; Chung, Kiwhan [Los Alamos National Laboratory; Macarthur, Duncan W [Los Alamos National Laboratory

    2010-01-01

    In this paper we report on the design of a multilayer thermal neutron detector based on {sup 6}Li reactive foil and thin film plastic scintillators. The {sup 6}Li foils have about twice the intrinsic efficiency of {sup 10}B films and about four times higher light output due to a unique combination of high energy of reaction particles, low self absorption, and low ionization density of tritons. The design configuration provides for double sided readout of the lithium foil resulting in a doubling of the efficiency relative to a classical reactive film detector and generating a pulse height distribution with a valley between neutron and gamma signals similar to {sup 3}He tubes. The tens of microns thickness of plastic scintillator limits the energy deposited by gamma rays, which provides the necessary neutron/gamma discrimination. We used MCNPX to model a multilayer Li foil detector design and compared it with the standard HLNCC-II (18 {sup 3}He tubes operated at 4 atm). The preliminary results of the {sup 6}Li configuration show higher efficiency and one third of the die-away time. These properties, combined with the very short dead time of the plastic scintillator, offer the potential of a very high performance detector.

  12. The {sup 3}He(e,e'p){sup 2}H and {sup 4}He(e,e'p){sup 3}H reactions at high momentum transfer

    Energy Technology Data Exchange (ETDEWEB)

    Ford, William P. [Old Dominion University, Norfolk, VA (United States); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Schiavilla, Rocco [Old Dominion University, Norfolk, VA (United States); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Van Orden, J. W. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-03-01

    We present updated calculations for observables in the processes {sup 3}He(e,e'p){sup 2}H, {sup 4}He(e,e'p){sup 3}H and {sup 4}He(e-vector, e'p-vector){sup 3}H. This update entails the implementation of improved nucleon-nucleon (NN) amplitudes to describe final state interactions (FSI) within a Glauber approximation and includes full spin-isospin dependence in the profile operator. In addition, an optical potential, which has also been updated since previous work, is utilized to treat FSI for the {sup 4}He(e,e'p){sup 3}H and {sup 4}He(e-vector, e'p-vector){sup 3}H reactions. The calculations are compared with experimental data and show good agreement between theory and experiment. Comparisons are made between the various approximations in the Glauber treatment, including model dependence due to the NN scattering amplitudes, rescattering contributions, and spin dependence. We also analyze the validity of the Glauber approximation at the kinematics the data is available, by comparing to the results obtained with the optical potential.

  13. Big Bang 6Li nucleosynthesis studied deep underground (LUNA collaboration)

    Science.gov (United States)

    Trezzi, D.; Anders, M.; Aliotta, M.; Bellini, A.; Bemmerer, D.; Boeltzig, A.; Broggini, C.; Bruno, C. G.; Caciolli, A.; Cavanna, F.; Corvisiero, P.; Costantini, H.; Davinson, T.; Depalo, R.; Elekes, Z.; Erhard, M.; Ferraro, F.; Formicola, A.; Fülop, Zs.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyürky, Gy.; Junker, M.; Lemut, A.; Marta, M.; Mazzocchi, C.; Menegazzo, R.; Mossa, V.; Pantaleo, F.; Prati, P.; Rossi Alvarez, C.; Scott, D. A.; Somorjai, E.; Straniero, O.; Szücs, T.; Takacs, M.

    2017-03-01

    The correct prediction of the abundances of the light nuclides produced during the epoch of Big Bang Nucleosynthesis (BBN) is one of the main topics of modern cosmology. For many of the nuclear reactions that are relevant for this epoch, direct experimental cross section data are available, ushering the so-called "age of precision". The present work addresses an exception to this current status: the 2H(α,γ)6Li reaction that controls 6Li production in the Big Bang. Recent controversial observations of 6Li in metal-poor stars have heightened the interest in understanding primordial 6Li production. If confirmed, these observations would lead to a second cosmological lithium problem, in addition to the well-known 7Li problem. In the present work, the direct experimental cross section data on 2H(α,γ)6Li in the BBN energy range are reported. The measurement has been performed deep underground at the LUNA (Laboratory for Underground Nuclear Astrophysics) 400 kV accelerator in the Laboratori Nazionali del Gran Sasso, Italy. The cross section has been directly measured at the energies of interest for Big Bang Nucleosynthesis for the first time, at Ecm = 80, 93, 120, and 133 keV. Based on the new data, the 2H(α,γ)6Li thermonuclear reaction rate has been derived. Our rate is even lower than previously reported, thus increasing the discrepancy between predicted Big Bang 6Li abundance and the amount of primordial 6Li inferred from observations.

  14. Updated evidences of the Trojan Horse particle invariance for $^2$H(d,p)$^3$H reaction

    CERN Document Server

    Pizzone, R G; Bertulani, C A; Mukhamedzhanov, A M; Blokhintsev, L; La Cognata, M; Lamia, L; Rinollo, A; Spartá, R; Tumino, A

    2012-01-01

    The Trojan Horse nucleus invariance for the binary d(d,p)t reaction was tested using the quasi free $^2$H($^6$Li, pt)$^4$He and $^2$H($^3$He,pt)H reactions after $^6$Li and $^3$He break-up, respectively. The astrophysical S(E)-factor for the d(d,p)t binary process was then extracted in the framework of the Plane Wave Approximation applied to the two different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the Plane Wave Approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present case.

  15. Cosmic Ray ^3He Measurements

    OpenAIRE

    Mewaldt, R. A.

    1985-01-01

    Cosmic ray ^3He/^4He observations, including a new measurement at ~65 MeV/nucleon from ISEE-3, are compared with interstellar propagation and solar modulation models in an effort to understand the origin of cosmic ray He nuclei.

  16. 2H(d,n)3He核反应中子注量的伴随粒子法测量%An associated particle method to measure the neutron flux from the 2H(d,n)3He reaction

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    2H(d,n)3He核反应单能中子源广泛应用于几MeV中子的散射和极化实验.采用伴随粒子法测量中子注量,用Si半导体探测器测量3He粒子,用0.8μm Al箔来屏蔽散射的d束,系统可很好地分辨3He、d、T和 p,可测d+束能量到165keV,测量结果与用NE213探测器的结果相比较,一致性好于97%.

  17. Evidence of Cluster Structure of $^9$Be from $^3$He+$^9$Be Reaction

    CERN Document Server

    Lukyanov, S M; Naumenko, M A; Xu, Yi; Trzaska, W H; Burjan, V; Kroha, V; Mrazek, J; Glagolev, V; Piskoř, Š; Voskoboynik, E I; Khlebnikov, S V; Penionzhkevich, Yu E; Skobelev, N K; Sobolev, Yu G; Tyurin, G P; Kuterbekov, K; Tuleushev, Yu

    2015-01-01

    The study of inelastic scattering and multi-nucleon transfer reactions was performed by bombarding a $^{9}$Be target with a $^3$He beam at an incident energy of 30 MeV. Angular distributions for $^9$Be($^3$He,$^3$He)$^{9}$Be, $^9$Be($^3$He,$^4$He)$^{8}$Be, $^9$Be($^3$He,$^5$He)$^{7}$Be, $^9$Be($^3$He,$^6$Li)$^6$Li and $^9$Be($^3$He,$^5$Li)$^7$Li reaction channels were measured. Experimental angular distributions for the corresponding ground states (g.s.) were analysed within the framework of the optical model, the coupled-channel approach and the distorted-wave Born approximation. Cross sections for channels leading to unbound $^5$He$_{g.s.}$, $^5$Li$_{g.s.}$ and $^8$Be systems were obtained from singles measurements where the relationship between the energy and the scattering angle of the observed stable ejectile is constrained by two-body kinematics. Information on the cluster structure of $^{9}$Be was obtained from the transfer channels. It was concluded that cluster transfer is an important mechanism in t...

  18. Characterization of the silicon+6LiF thermal neutron detection technique

    Science.gov (United States)

    Pappalardo, A.; Barbagallo, M.; Cosentino, L.; Marchetta, C.; Musumarra, A.; Scirè, C.; Scirè, S.; Vecchio, G.; Finocchiaro, P.

    2016-02-01

    The worldwide need to replace 3He for neutron detection has triggered research and development on new technologies and methods. A promising one is based on commercial solid state silicon detectors coupled with thin neutron converter layers containing 6Li. After proving the feasibility of this technique, we characterized the behavior of such a detector with different converter layer thicknesses. In this paper we also disentangle other contributions to the overall spectrum shape observed with this kind of detector, proving that its detection efficiency can be made reasonably high and that the gamma/neutron discrimination capability is comparable to that of 3He tubes.

  19. Characterization of the silicon+6LiF thermal neutron detection technique

    CERN Document Server

    Pappalardo, A; Cosentino, L; Marchetta, C; Musumarra, A; Scirè, C; Scirè, S; Vecchio, G; Finocchiaro, P

    2015-01-01

    The worldwide need to replace 3He for the neutron detection has triggered R&D on new technologies and methods. A promising one is based on commercial solid state silicon detectors coupled with thin neutron converter layers containing 6Li. After proving the feasibility of this technique, we characterized the behavior of such a detector with different converter layer thicknesses. In this paper we also disentangle other contributions to the overall spectrum shape observed with this kind of detector, proving that its detection efficiency can be made reasonably high and that the gamma/neutron discrimination capability is comparable to the one of 3He tubes.

  20. Characterization of the silicon+{sup 6}LiF thermal neutron detection technique

    Energy Technology Data Exchange (ETDEWEB)

    Pappalardo, A. [INFN Laboratori Nazionali del Sud, Catania (Italy); Barbagallo, M. [INFN Sezione di Bari (Italy); Cosentino, L.; Marchetta, C. [INFN Laboratori Nazionali del Sud, Catania (Italy); Musumarra, A. [INFN Laboratori Nazionali del Sud, Catania (Italy); Università di Catania (Italy); Scirè, C.; Scirè, S.; Vecchio, G.; Finocchiaro, P. [INFN Laboratori Nazionali del Sud, Catania (Italy)

    2016-02-21

    The worldwide need to replace {sup 3}He for neutron detection has triggered research and development on new technologies and methods. A promising one is based on commercial solid state silicon detectors coupled with thin neutron converter layers containing {sup 6}Li. After proving the feasibility of this technique, we characterized the behavior of such a detector with different converter layer thicknesses. In this paper we also disentangle other contributions to the overall spectrum shape observed with this kind of detector, proving that its detection efficiency can be made reasonably high and that the gamma/neutron discrimination capability is comparable to that of {sup 3}He tubes.

  1. Using Inertial Fusion Implosions to Measure the T+^{3}He Fusion Cross Section at Nucleosynthesis-Relevant Energies.

    Science.gov (United States)

    Zylstra, A B; Herrmann, H W; Johnson, M Gatu; Kim, Y H; Frenje, J A; Hale, G; Li, C K; Rubery, M; Paris, M; Bacher, A; Brune, C R; Forrest, C; Glebov, V Yu; Janezic, R; McNabb, D; Nikroo, A; Pino, J; Sangster, T C; Séguin, F H; Seka, W; Sio, H; Stoeckl, C; Petrasso, R D

    2016-07-15

    Light nuclei were created during big-bang nucleosynthesis (BBN). Standard BBN theory, using rates inferred from accelerator-beam data, cannot explain high levels of ^{6}Li in low-metallicity stars. Using high-energy-density plasmas we measure the T(^{3}He,γ)^{6}Li reaction rate, a candidate for anomalously high ^{6}Li production; we find that the rate is too low to explain the observations, and different than values used in common BBN models. This is the first data directly relevant to BBN, and also the first use of laboratory plasmas, at comparable conditions to astrophysical systems, to address a problem in nuclear astrophysics.

  2. Using Inertial Fusion Implosions to Measure the T + 3He Fusion Cross Section at Nucleosynthesis-Relevant Energies

    Science.gov (United States)

    Zylstra, A. B.; Herrmann, H. W.; Johnson, M. Gatu; Kim, Y. H.; Frenje, J. A.; Hale, G.; Li, C. K.; Rubery, M.; Paris, M.; Bacher, A.; Brune, C. R.; Forrest, C.; Glebov, V. Yu.; Janezic, R.; McNabb, D.; Nikroo, A.; Pino, J.; Sangster, T. C.; Séguin, F. H.; Seka, W.; Sio, H.; Stoeckl, C.; Petrasso, R. D.

    2016-07-01

    Light nuclei were created during big-bang nucleosynthesis (BBN). Standard BBN theory, using rates inferred from accelerator-beam data, cannot explain high levels of 6Li in in low-metallicity stars. Using high-energy-density plasmas we measure the T (3He, ,γ )6Li reaction rate, a candidate for anomalously high 6Li production; we find that the rate is too low to explain the observations, and different than values used in common BBN models. This is the first data directly relevant to BBN, and also the first use of laboratory plasmas, at comparable conditions to astrophysical systems, to address a problem in nuclear astrophysics.

  3. The Panofsky ratio in 3He

    Science.gov (United States)

    Corriveau, F.; Hasinoff, M. D.; Measday, D. F.; Poutissou, J.-M.; Salomon, M.

    1987-11-01

    The branching ratios have been measured for γ-ray channels produced by π- stopping in liquid 3He. The results for the Panofsky ratio are P3 = ω( π-3He → π0t)/ ω( π-3He → γt) = 2.83 ± 0.07, and for the ratio of the radiative breakup channels, B3 = ω)( π-3He → γnd + γnnp)/ ω( π-3He → γt) = 1.35 ±0.11.

  4. Tritium/ 3He dating of shallow groundwater

    Science.gov (United States)

    Schlosser, Peter; Stute, Martin; Dörr, Helmut; Sonntag, Christian; Münnich, Karl Otto

    1988-08-01

    Combined tritium/ 3He data from three multi-level sampling wells (DFG 1, DFG 4, DFG 7) located at Liedern/ Bocholt, West Germany, are presented and principles of the tritium/ 3He method in shallow groundwater studies are discussed. The 3He excess produced by radioactive decay of bomb tritium (released mainly between 1952 and 1963) is clearly reflected in the data. The tritiogenic 3He signal can be detected with a good resolution (signal/1σ error: ≈ 350). The confinement of the tritiogenic 3He is estimated to approximately 77-85% at site DFG 4. For the bomb tritium peak the deviation of the tritium/ 3He age from the age determined by identifying the groundwater layer recharged between 1962 and 1965 is about 3 years (15%). The deviation can be explained by diffusive 3He loss across the groundwater table and by flow dispersion.

  5. Trojan Horse particle invariance for 2H(d,p3H reaction: a detailed study

    Directory of Open Access Journals (Sweden)

    Pizzone R.G.

    2014-03-01

    Full Text Available In the last decades the Trojan Horse method has played a crucial role for the measurement of several charged particle induced reactions cross sections of astrophysical interest. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance for the binary d(d,pt reaction was therefore tested using the quasi free 2H(6Li, pt4He and 2H(3He,ptH reactions after 6Li and 3He break-up, respectively. The astrophysical S(E-factor for the d(d,pt binary process was then extracted in the framework of the Plane Wave Approximation applied to the two different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the plane wave approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present case.

  6. Pulse-Shape Analysis of Neutron-Induced Scintillation Light in Ni-doped 6LiF/ZnS

    Energy Technology Data Exchange (ETDEWEB)

    Cowles, Christian C.; Behling, Richard S.; Imel, G. R.; Kouzes, Richard T.; Lintereur, Azaree; Robinson, Sean M.; Stave, Sean C.; Siciliano, Edward R.; Wang, Zheming

    2016-10-06

    Abstract–Alternatives to 3He are being investigated for gamma-ray insensitive neutron detection applications, including plutonium assay. One promising material is lithium-6 fluoride with silver activated zinc sulfide 6LiF/ZnS(Ag) in conjunction with a wavelength shifting plastic. Doping the 6LiF/ZnS(Ag) with nickel (Ni) has been proposed as a means of reducing the decay time of neutron signal pulses. This research performed a pulse shape comparison between Ni-doped and non-doped 6LiF/ZnS(Ag) neutron pulses. The Ni-doped 6LiF/ZnS(Ag) had a 32.7% ± 0.3 increase in neutron pulse height and a 32.4% ± 0.3 decrease in neutron pulse time compared to the non-doped 6LiF/ZnS(Ag). Doping 6LiF/ZnS(Ag) with nickel may allow neutron detector operation with improved signal to noise ratios, and reduced pulse pileup affects, increasing the accuracy and range of source activities with which such a detector could operate.

  7. Tritiogenic 3He in shallow groundwater

    Science.gov (United States)

    Schlosser, Peter; Stute, Martin; Sonntag, Christian; Otto Münnich, Karl

    1989-09-01

    Tritium, helium isotope and neon data from a multi-level sampling well (DFG 7) at Liedern/Bocholt (West Germany) are presented and discussed. The presence of a radiogenic helium component leads to 3He/ 4He ratios below that of atmospheric helium ( minimumδ 3He values≈ -60% ) below about 20 m depth. The 3He profile can be corrected for the nucleogenic 3He component using the neon measurements. Based on the "Vogel" model of a shallow aquifer the tritium/ 3He distributions are simulated for the years 1987, 2000 and 2025. The model results show that under favourable conditions the tritiogenic 3He peak will be detectable in shallow aquifers for at least the next 4 decades. The influence of the vertical flow velocity and the transversal dispersion coefficient on simulated distributions are estimated. 3He confinement is calculated as a function of the vertical flow velocity and the transversal dispersion coefficient. There is a critical value of the vertical flow velocity (about 0.25-0.5 m/year) below which the 3He loss increases rapidly to high values.

  8. Tritiogenic sup 3 He in shallow groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Schlosser, P.; Stute, M.; Sonntag, C.; Muennich, K.O. (Heidelberg Univ. (Germany, F.R.). Inst. fuer Umweltphysik)

    1989-09-01

    Tritium, helium isotope and neon data from a multi-level sampling well (DFG 7) at Liedern/Bocholt (West Germany) are presented and discussed. The presence of a radiogenic helium component leads to {sup 3}He/{sup 4}He ratios below that of atmospheric helium (minimum {delta}{sup 3}He values {approx equal} -60%) below about 20 m depth. The {sup 3}He profile can be corrected for the nucleogenic {sup 3}He component using the neon measurements. Based on the ''Vogel'' model of a shallow aquifer the tritium/{sup 3}He distributions are simulated for the years 1987, 2000 and 2025. The model results show that under favourable conditions the tritiogenic {sup 3}He peak will be detectable in shallow aquifers for at least the next 4 decades. The influence of the vertical flow velocity and the transversal dispersion coefficient on simulated distributions are estimated. {sup 3}He confinement is calculated as a function of the vertical flow velocity and the transversal dispersion coefficient. There is a critical value of the vertical flow velocity (about 0.25-0.5 m/year) below which the {sup 3}He loss increases rapidly to high values. (orig.).

  9. Triple α resonances in the 6Li + 6Li → 3α reaction at low energy

    Directory of Open Access Journals (Sweden)

    A. Tumino

    2015-11-01

    Full Text Available The 6Li + 6Li → 3α reaction has been measured in a kinematically complete experiment at 3.1 MeV of beam energy. The reaction mainly proceeds via intermediate 8Be states. The interaction between any two of the three α particles provides events with one, two or three 8Be interfering levels, with strong enhancement in the α–α coincidence yield. Evidence of three 8Be levels within the same 3α event suggests that one α particle is exchanged between the other two. This is a condition for Efimov states to occur in nuclei, for which no observation exists yet. The hyperspherical formalism for the low-energy three-body problem has been applied to point out the 3α particle correlation.

  10. Diffusion of $^{6}$Li in Ta and W

    CERN Document Server

    Vacik, J

    2006-01-01

    The objective of this work was the study of 6Li diffusion in the Ta and W refractory metals. The samples were prepared by ion implantation of 380 keV 6Li+ ions into W and Ta thin foils (up to the fluence of 1016 ions/cm2) and annealed up to the temperature 1940 °C. The depth profiles of 6Li were determined using the Thermal Neutron Depth Profiling (TNDP) technique. The results showed that diffusion of 6Li in both W and Ta foils is very complex and cannot be described by simple Fick’s laws. Trapping centers (in the subsurface layers of both W and Ta metals) were supposed in a trial to explain the 6Li diffusion behaviour. However, the 6Li depth profiles were only partly explained. Other aspects are necessary to take into account for more proper quantification; such as spatially dependent diffusion coefficients, etc.

  11. 6^Li in the atmosphere of GJ 117

    CERN Document Server

    Christian, D J; Jevremovic, D; Hauschildt, P H; Baron, E

    2005-01-01

    We present high resolution VLT UVES observations of the active K dwarf GJ 117. 6^Li enhancement has been shown for energetic solar events, one chromospherically active binary, and several dwarf halo stars. Our analysis reveals the detection of 6^Li on this source with 6^Li/7^Li = 0.030+/-0.010. We found no significant contribution from other lines, including Ti I, in the Li profile of GJ 117 and a template star of similar spectral type and metallicity. We discuss the possibility for 6^Li production by spallation and find it to be consistent with the activity levels of the object.

  12. 3He melting pressure temperature scale

    DEFF Research Database (Denmark)

    Halperin, W.P.; Archie, C.N.; Richardson, R.C.;

    1976-01-01

    The latent heat for solidification of **3He has been measured along the **3He melting curve between 23 and 1 mK. A temperature scale is established which depends only on measurements of heat, pressure and volume, and on the condition that the entropy of solid **3He approaches R ln 2 at high...... temperatures. The A feature of the melting curve which suggests itself as a thermometric fixed point is found to be T//A equals 2. 75 plus or minus 0. 11 mK. The agreement between this value and independent measurements of T//A, based on nuclear or electronic paramagnetism, Johnson noise thermometry...

  13. Four-body dynamics in 6Li elastic scattering

    CERN Document Server

    Watanabe, Shin; Ogata, Kazuyuki; Yahiro, Masanobu

    2015-01-01

    We analyze 6Li elastic scattering in a wide range of incident energies (Ein), assuming the n + p + alpha + target four-body model and solving the dynamics with the four-body version of the continuum-discretized coupled-channels method (CDCC). Four-body CDCC well reproduces the experimental data with no adjustable parameter for 6Li + 209Bi scattering at Ein = 24-50 MeV and 6Li + 208Pb scattering at Ein = 29-210 MeV. In the wide Ein range, 6Li breakup is significant and provides repulsive corrections to the folding potential. As an interesting property, d breakup is strongly suppressed in 6Li-breakup processes independently of Ein. We investigate what causes the d-breakup suppression.

  14. Coherent Photoproduction of pi^+ from 3/^He

    Energy Technology Data Exchange (ETDEWEB)

    Rakhsha Nasseripour, Barry Berman

    2011-03-01

    We have measured the differential cross section for the $\\gamma$$^3$He$\\rightarrow \\pi^+ t$ reaction. This reaction was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Real photons produced with the Hall-B bremsstrahlung tagging system in the energy range from 0.50 to 1.55 GeV were incident on a cryogenic liquid $^3$He target. The differential cross sections for the $\\gamma$$^3$He$\\rightarrow \\pi^+ t$ reaction were measured as a function of photon-beam energy and pion-scattering angle. Theoretical predictions to date cannot explain the large cross sections except at backward angles, showing that additional components must be added to the model.

  15. Photoproduction of eta-mesic 3He

    CERN Document Server

    Pfeiffer, M; Annand, J R M; Beck, R; Caselotti, G; Cherepnya, S N; Föhl, K; Fog, L S; Hornidge, D; Janssen, S; Kashevarov, V; Kondratiev, R; Kotulla, M; Krusche, B; McGeorge, J C; MacGregor, I J D; Mengel, K; Messchendorp, J G; Metag, V; Novotny, R; Rost, M; Sack, S; Sanderson, R; Schadmand, S; Thomas, A; Watts, D P

    2003-01-01

    The photoproduction of eta-mesic 3He has been investigated using the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI. The total inclusive cross section for the reaction gamma+3He->eta+X has been measured for photon energies from threshold to 820 MeV. The total and angular differential coherent eta cross sections have been extracted up to energies of 745 MeV. A resonance-like structure just above the eta production threshold with an isotropic angular distribution suggests the existence of a resonant quasi-bound state. This is supported by studies of a competing decay channel of such a quasi-bound eta-mesic nucleus into pi^0+p+X. A binding energy of (4+-4) MeV and a width of (25+-6) MeV is deduced for the quasi-bound eta-mesic state in 3He.

  16. Barshay-Temmer test for the 4He( overlined, 3He) 3H reaction

    Science.gov (United States)

    Bruno, M.; Cannata, F.; D'agostino, M.; Fiandri, M. L.; Herman, M.; Hofmann, H. M.; Vuaridel, B.; Grüebler, W.; König, V.; Schmelzbach, P. A.; Elsener, K.

    1989-09-01

    The mechanisms of isospin violation in the reaction 4He( overlined, 3He) 3H is studied, in the framework of a microscopic model. To describe realistically the intermediate 6Li nucleus and the fragment states we use the refined resonating group model (RRGM). A detailed analysis of the matrix elements responsible for the asymmetry of cross sections and vector analyzing powers is presented. The isospin violation is found typically of the order of 5-10% and arises mainly from coupling to intermediate "5 + 1" structures in a two-step mechanism. The agreement with the experimental data is fair.

  17. Development of a 6LiF/ZnS-based Neutron Multiplicity Counter

    Energy Technology Data Exchange (ETDEWEB)

    Stave, Sean C.; Behling, Richard S.; Bernacki, Bruce E.; Bliss, Mary; Cowles, Christian C.; Kouzes, Richard T.; Lintereur, Azaree; Robinson, Sean M.; Siciliano, Edward R.

    2016-10-06

    Abstract–Neutron multiplicity counters are used in safeguards to provide rapid assay of samples which contain an unknown amount of plutonium in a potentially unknown configuration. A project at PNNL is using regular and nickel-quenched 6LiF/ZnS neutron-scintillator sheets and wavelength shifting plastic for light pipes in place of 3He. A combination of laboratory and modeling work predicts a LiF/ZnS-based system to be able to match or exceed the performance of the best 3He-based systems available. Also, the Ni-quenched material is expected to allow for improved neutron/gamma-ray discrimination at twice the event rate relative to the non-Ni-quenched LiF/ZnS. A new system based on the LiF/ZnS material is under construction and components are being used to optimize the detection efficiency and neutron/gamma-ray discrimination properties. Components of the new system are partially constructed and undergoing performance testing utilizing high-speed digitizers with field programmable gate arrays to perform the neutron/gamma-ray discrimination. The expected performance of the full-scale system is expected to be nearly the same as for 3He-based systems and is due for completion in 2016.

  18. Galactic evolution of D and $^{3}$He including stellar production of $^{3}$He

    CERN Document Server

    Dearborn, D S P; Tosi, M P

    1996-01-01

    New stellar models which track the production and destruction of ^3He (and D) have been evolved for a range of stellar masses (0.65\\leq M/M_{\\odot}\\leq 100), metallicities (0.01 \\leq Z/Z_{\\odot} \\leq 1) and initial (main sequence) ^3He mass fractions (10^{-5} \\leq X_{3,MS} \\leq 10^{-3}). Armed with the ^3He yields from these stellar models we have followed the evolution of D and ^3He using a variety of chemical evolution models with and without infall of primordial or processed material. Production of new ^3He by the lower mass stars overwhelms any reasonable primordial contributions and leads to predicted abundances in the presolar nebula and/or the present interstellar medium in excess of the observationally inferred values. This result, which obtains even for zero primordial D and ^3He, and was anticipated by Rood, Steigman \\& Tinsley (1976), is insensitive to the choice of chemical evolution model; it is driven by the large ^3He yields from low mass stars. In an attempt to ameliorate this problem we h...

  19. Neutron scattering from solid 3He

    Science.gov (United States)

    Schanen, R.; Sherline, T. E.; Toader, A. M.; Boyko, V.; Mat'as, S.; Meschke, M.; Schöttl, S.; Adams, E. D.; Cowan, B.; Godfrin, H.; Goff, J. P.; Roger, M.; Saunders, J.; Siemensmeyer, K.; Takano, Y.

    2003-05-01

    Multiple spin exchange leads, according to present understanding, to a variety of magnetically ordered states in solid 3He, depending on pressure and applied magnetic field. We report the status of experiments to directly determine these structures by neutron scattering. The large neutron absorption cross section, and associated sample heating, impose severe experimental demands on the design of the sample cell. We report on our proposed solution, including details of the sintered heat exchanger necessary to cool the sample, as well as the PrNi 5 nuclear demagnetization stage. The use of NMR in parallel experiments to characterise growth of the solid sample within the sinter is also discussed.

  20. Buffer-gas-assisted polarization spectroscopy of 6Li.

    Science.gov (United States)

    Ohtsubo, Nozomi; Aoki, Takatoshi; Torii, Yoshio

    2012-07-15

    We report on the demonstration of Doppler-free polarization spectroscopy of the D2 line of (6)Li atoms. Counterintuitively, the presence of an Ar buffer gas, in a certain pressure range, causes a drastic enhancement of the polarization rotation signal. The observed dependence of the signal amplitude on the Ar buffer pressure and the pump laser power is reproduced by calculations based on simple rate equations. We performed stable laser frequency locking using a dispersion signal obtained by polarization spectroscopy for laser cooling of (6)Li atoms.

  1. Study of the (p,d/sup 3/He) reaction as a quasi-free reaction process

    Energy Technology Data Exchange (ETDEWEB)

    Cowley, A. A.; Roos, P. G.; Chant, N. S.; Woody, R. III; Holmgren, H. D.; Goldberg, D. A.

    1976-11-01

    The (p,d/sup 3/He) reaction on /sup 6/Li, /sup 7/Li, /sup 9/Be, and /sup 12/C has been investigated in conjunction with studies of the (p,p..cap alpha..) reaction on the same targets. Coincident data for all four targets were obtained at a bombarding energy of 100 MeV for numerous angle pairs in order to test the reaction mechanism. Comparisons of the (p,d/sup 3/He) data to both (p,p..cap alpha..) data and distorted wave impulse approximation calculations (DWIA) indicate a dominance of the direct quasi-free reaction process (p + alpha yields d + /sup 3/He). The absolute alpha-particle spectroscopic factors extracted using DWIA analysis are in agreement with the values obtained in the (p,p..cap alpha..) reaction.

  2. Characteristics of a thermal neutrons scintillation detector with the [ZnS(Ag)+$^6$LiF] at different conditions of measurements

    OpenAIRE

    Alekseenko, V. V.; Barabanov, I. R.; Etezov, R. A.; Gavrilyuk, Yu. M.; Gangapshev, A. M.; Gezhaev, A. M.; Kazalov, V. V.; Khokonov, A. Kh.; V.V. Kuzminov; Panasenko, S. I.; Ratkevich, S. S.

    2015-01-01

    A construction of a thermal neutron testing detector with a thin [ZnS(Ag)+$^6$LiF] scintillator is described. Results of an investigation of sources of the detector pulse origin and the pulse features in a ground and underground conditions are presented. Measurements of the scintillator own background, registration efficiency and a neutron flux at different objects of the BNO INR RAS were performed. The results are compared with the ones measured by the $^3$He proportional counter.

  3. Reaction mechanisms in the 6Li+ 52Cr system

    Directory of Open Access Journals (Sweden)

    Pandey Bhawna

    2015-01-01

    Full Text Available Reactions induced by the weakly bound 6Li projectile interacting with the intermediate mass target 52Cr are investigated. The choice of this particular reaction in our study is because it is proposed as a surrogate reaction [6Li(52Cr, d56Fe*] for the measurement of 55Fe(n,p reaction cross-section, which has been found to be very important in fusion reactor studies. All the conditions which have to be satisfied for using the surrogate method have been checked. The energy of 6Li beam is selected in a way so as to get equivalent neutron energy in the region of 9-14 MeV, which is of primary interest in fusion reactor application. In the present work, statistical model calculations PACE (Projection-Angular-Momentum-Coupled-Evaporation, ALICE and Continuum-Discretized–Coupled-Channel (CDCC: FRESCO have been used to provide information for the 6Li + 52Cr system and the respective contributions of different reaction mechanisms. The present theoretical work is an important step in the direction towards studying the cross-section of the 55Fe(n, p55Mn reaction by surrogate method.

  4. Search for the Halo Effect in the ~1H(~6He, ~6Li)n Reaction

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The experiment is carried out using the secondary beam facility of the HI-13 tandem accelerator at China Institute of Atomic Energy, Beijing. The experimental setup is similar to the previously illustrated. A 7Li beam with energy of 44 MeV from the tandem impinged on a D2 gas cell at pressure of 1.5×105 Pa, in which 6He ions are produced via 2H(7Li, 6He)3He reaction. The front and rear

  5. {eta} photoproduction off {sup 3}He

    Energy Technology Data Exchange (ETDEWEB)

    Witthauer, Lilian [Department of Physics, University Basel (Switzerland)

    2010-07-01

    Quark models predict many more states in the excitation spectrum of the nucleon than observed in experiments. Most previous experiments investigating the excitation spectrum of nucleons are based on elastic scattering of charged pions. This makes it probable that the data is biased against states that couple only weakly to N{pi}. Hence, one can study different excitation mechanisms and channels as the photoproduction of mesons via excitation of nucleon resonances. Measurements at ELSA in Bonn investigated the quasi-free {eta} photoproduction off the neutron (I. Jaegle et al., Phys. Rev. Lett 100 (2008) 252002). The resulting cross section shows a narrow structure at W=1.68 GeV with a width smaller than 60 MeV. This structure is only visible in the cross section on the neutron and not in that on the proton. Experiments of the GRAAL collaboration (V.Kuznetsov et al., arXiv:hep-ex/0606065v2) and LNS-Sendai (F. Miyahara et al., Prog. Theor. Phys. Suppl. 168 (2007) 90) showed the same effect in quasi-free photoproduction off the deuteron. In order to exclude any possibility that the structure could arise from nuclear effects (re-scattering of mesons, final state interaction) we have studied it for a nucleon system with different momentum distribution and different neutron/proton ratio, namely {sup 3}He. Preliminary results for the quasi-free {eta} cross section obtained in coincidence with recoil nucleons will be discussed.

  6. Unusual Threshold Anomaly in the 6Li+208Pb System

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun-Lei; JIA Hui-Ming; WU Zhen-Dong; XU Xin-Xing; BAI Chun-Lin; ZHANG Huan-Qiao; LIN Cheng-Jian; RUAN Ming; LIU Zu-Hua; YANG Feng; WU Xiu-Kun; ZHOU Ping; AN Guang-Peng

    2006-01-01

    @@ The angular distributions of elastic scattering for the 6Li +208Pb system have been measured at several energies around the Coulomb barrier. The parameters of optical potential are extracted by means of a phenomenological optical model analysis. It is found that the real and imaginal potentials show a pronounced energy dependence.The behaviour of the potential at the nearly especially sub-barrier energies in the 6Li+208Pb system is quite different from the results of some previous reports observed in other systems, such as 19 F +208 Pb and 16 O+208 Pb.This unusual threshold phenomenon indicates that breakup channel is strongly coupled with the elastic channel and has obvious effects on optical potential.

  7. Reactions pd-->3He η and pd-->3He π+π- near the η threshold

    Science.gov (United States)

    Mayer, B.; Boudard, A.; Fabbro, B.; Garçon, M.; Kerboul, C.; Poitou, J.; Wellers, F.; Jacobs, W. W.; Saudinos, J.; Tomasi-Gustafsson, E.; Mouly, J. P.; Kessler, R. S.; Nefkens, B. M.; Tippens, B.; van der Schaaf, A.; Abegg, R.; van Oers, W. T.; Briscoe, W.; Petrov, A.; Moalem, A.

    1996-05-01

    The reaction pd-->3Heη has been studied with the SPES2 spectrometer, for proton energies between 0.2 MeV and 11 MeV above threshold. The total cross section rises from 0.25 to 0.40 μb in this region. The observed energy dependence can be attributed to the strong final state interaction. The angular distribution is nearly isotropic, consistent with S wave production. A measurement of the pd-->3Heπ+π- cross section in the threshold region is also presented. The setup, which is capable of producing 105 tagged η/s with only a few percent background, is used to investigate rare η decays.

  8. (p,px) reaction on /sup 6/Li and /sup 7/Li nuclei at incident proton energy of 70 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Gorpinich, O.K.; Kadkin, E.P.; Kondrat' ev, S.N.; Lobach, Yu.M.; Pasechnik, M.V.; Saltykov, L.S.; Tokarevskij, V.V. (AN Ukrainskoj SSR, Kiev. Inst. Yadernykh Issledovanij)

    1983-01-01

    Measurements of two-dimensional coincidence spectra of charged particles from the /sup 6/Li(p, 2p)/sup 5/He, /sup 6/Li(p, p..cap alpha..)/sup 2/H, /sup 7/Li(p, pt)/sup 4/He, /sup 7/Li(p, p..cap alpha..)/sup 3/H reactions has been carried out using the equipment for simultaneous investigation of correlation of charged particles of different types. The /sup 6/Li(p, pd) reaction probability reaches the maximum value when the residual nucleus momentum is close to zero. This fact may confirm an existance of strong /sup 6/Li ..cap alpha..d-clusterization. The /sup 7/Li(p, pt) reaction occurs with the minimum probability in a quasi-free region that confirms /sup 7/Li ..cap alpha..t-structure. A direct comparison of particle two-dimensional spectra projections of (p, px) type reactions reveals that a probability of quasi-free scattering of proton on deuteron (triton) /sup 6/Li(/sup 7/Li) cluster is higher than quasi-free scattering on intranuclear protons. This fact is also confirmed by an assumption on ..cap alpha..d(..cap alpha..t)-cluster /sup 6/Li(/sup 7/Li) nucleus structure.

  9. Investigation of a lithium foil multi-wire proportional counter for potential {sup 3}He replacement

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Kyle A., E-mail: knelson1@ksu.edu [S.M.A.R.T. Laboratory, Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS 66506 (United States); Bellinger, Steven L.; Montag, Benjamin W.; Neihart, James L.; Riedel, Todd A.; Schmidt, Aaron J.; McGregor, Douglas S. [S.M.A.R.T. Laboratory, Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS 66506 (United States)

    2012-03-21

    The recent shortage in the supply of {sup 3}He for neutron detection has caused a large surge in research for a viable replacement. {sup 6}Li has a large cross section for the absorption of thermal neutrons and emits two relatively short-ranged interaction products. Li foil can now be manufactured thin enough to allow both reaction products to escape the foil. Ten layers of natural Li foil were placed in a multi-wire continuous flow gas chamber with a single anode wire between each foil. Four different thicknesses, 30, 50, 75 and 120 {mu}m, were tested in a thermalized neutron beam. The intrinsic thermal neutron detection efficiencies of 10 layers of 30, 50, and 75 {mu}m thick Li foil were measured to be 8.1, 11.1, and 15.7 percent. The n/{gamma} ratio was found to be 1.25 Multiplication-Sign 10{sup 7} using a {sup 137}Cs gamma-ray source. Additionally, neutron response pulse-height spectra of the four foil thicknesses are presented and compare well to simulated response spectra. Theoretical calculations show that thermal neutron detection efficiencies above 70 percent are achievable using enriched {sup 6}Li foils for the same detector geometries.

  10. Triple α resonances in the {sup 6}Li + {sup 6}Li → 3α reaction at low energy

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A., E-mail: tumino@lns.infn.it [Facoltà di Ingegneria e Architettura, Università degli Studi di Enna “Kore”, Enna (Italy); INFN, Laboratori Nazionali del Sud, Catania (Italy); Bonasera, A.; Giuliani, G. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Cyclotron Laboratory, Texas A& M University, College Station, TX (United States); Lattuada, M. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Milin, M. [Faculty of Science, University of Zagreb, Zagreb (Croatia); Pizzone, R.G. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Spitaleri, C. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Tudisco, S. [INFN, Laboratori Nazionali del Sud, Catania (Italy)

    2015-11-12

    The {sup 6}Li + {sup 6}Li → 3α reaction has been measured in a kinematically complete experiment at 3.1 MeV of beam energy. The reaction mainly proceeds via intermediate {sup 8}Be states. The interaction between any two of the three α particles provides events with one, two or three {sup 8}Be interfering levels, with strong enhancement in the α–α coincidence yield. Evidence of three {sup 8}Be levels within the same 3α event suggests that one α particle is exchanged between the other two. This is a condition for Efimov states to occur in nuclei, for which no observation exists yet. The hyperspherical formalism for the low-energy three-body problem has been applied to point out the 3α particle correlation.

  11. Barshay-Temmer test for the sup 4 He(d vector, sup 3 He) sup 3 H reaction

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, M.; Cannata, F.; D' Agostino, M.; Fiandri, M.L.; Herman, M. (Bologna Univ. (Italy). Dipt. di Fisica; Istituto Nazionale di Fisica Nucleare, Bologna (Italy)); Hofmann, H.M. (Erlangen-Nuernberg Univ., Erlangen (Germany, F.R.). Inst. fuer Theoretische Physik); Vuaridel, B.; Grueebler, W.; Koenig, V.; Schmelzbach, P.A.; Elsener, K. (Eidgenoessische Technische Hochschule, Zurich (Switzerland). Inst. fuer Mittelenergiephysik)

    1989-09-25

    The mechanisms of isospin violation in the reaction {sup 4}He(d vector,{sup 3}He){sup 3}H is studied, in the framework of a microscopic model. To describe realistically the intermediate {sup 6}Li nucleus and the fragment states we use the refined resonating group model (RRGM). A detailed analysis of the matrix elements responsible for the asymmetry of cross sections and vector analyzing powers is presented. The isospin violation is found typically of the order of 5-10% and arises mainly from coupling to intermediate '5+1' structures in a two-step mechanism. The agreement with the experimental data is fair. (orig.).

  12. Microscopic calculation of the spin-dependent neutron scattering lengths on 3He

    CERN Document Server

    Hofmann, H M

    2003-01-01

    We report on the spin.dependent neutron scattering length on 3He from a microscopic calculation of p-3H, n-3He, and d-2H scattering employing the Argonne v18 nucleon-nucleon potential with and without additional three-nucleon force. The results and that of a comprehensive R-matrix analysis are compared to a recent measurement. The overall agreement for the scattering lengths is quite good. The imaginary parts of the scattering lengths are very sensitive to the inclusion of three-nucleon forces, whereas the real parts are almost insensitive.

  13. Tritium//sup 3/He dating of shallow groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Schlosser, P.; Stute, M.; Doerr, H.; Sonntag, C.; Muennich, K.O.

    1988-08-01

    Combined tritium//sup 3/He data from three multi-level sampling wells (DFG 1, DFG 4, DFG 7) located at Liedern/Bocholt, West Germany, are presented and principles of the tritium//sup 3/He method in shallow groundwater studies are discussed. The /sup 3/He excess produced by radioactive decay of bomb tritium (released mainly between 1952 and 1963) is clearly reflected in the data. The tritiogenic /sup 3/He signal can be detected with a good resolution (signal/1sigma error: approx. = 350). The confinement of the tritiogenic /sup 3/He is estimated to approximately 77-85% at site DFG 4. For the bomb tritium peak the deviation of the tritium//sup 3/He age from the age determined by identifying the groundwater layer recharged between 1962 and 1965 is about 3 years (15%). The deviation can be explained by diffusive /sup 3/He loss across the groundwater table and by flow dispersion.

  14. Elastic and inelastic scattering of {sup 6}Li + {sup 18}O versus {sup 7}Li + {sup 18}O and {sup 6}Li + {sup 16}O

    Energy Technology Data Exchange (ETDEWEB)

    Rudchik, Adam T., E-mail: rudchik@kinr.kiev.ua [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Kliczewski, Stanislaw [H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Cracow (Poland); Chercas, Kostyantyn A. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Kemper, Kirby W. [Physics Department, Florida State University, Tallahassee, FL 32306-4350 (United States); Koshchy, Evgeniy I. [Kharkiv National University, pl. Svobody 4, 61077 Kharkiv (Ukraine); Rusek, Krzysztof [National Centre for Nuclear Research, ul. Hoża 69, PL-00-681 Warsaw (Poland); Heavy Ion Laboratory of Warsaw University, ul. L. Pasteura 5A, PL-02-093 Warsaw (Poland); Rudchik, Andryi A.; Mezhevych, Sergyi Yu.; Pirnak, Valeryi M. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Plujko, Volodymyr A. [Taras Shevchenko Kyiv National University, vul. Volodymyrs' ka 64, 01033 Kyiv (Ukraine); Ponkratenko, Oleg A. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Choiński, Jaroslaw [Heavy Ion Laboratory of Warsaw University, ul. L. Pasteura 5A, PL-02-093 Warsaw (Poland); Czech, Bronislaw; Siudak, Regina; Szczurek, Antoni [H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Cracow (Poland); Stolarz, Anna [Heavy Ion Laboratory of Warsaw University, ul. L. Pasteura 5A, PL-02-093 Warsaw (Poland); Zelinskyi, Ruslan M. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine)

    2014-02-15

    Inverse kinematics scattering of {sup 18}O on {sup 6}Li at E{sub lab}({sup 18}O) = 114 MeV was measured to obtain elastic and inelastic scattering cross sections. In this way cross sections for excited states in {sup 6}Li and {sup 18}O were determined. The data were analyzed within the optical model and coupled reaction channel method. The {sup 6}Li + {sup 18}O optical potential as well as the {sup 6}Li and {sup 18}O deformation parameters were deduced. Contributions of different nuclear processes to the {sup 6}Li + {sup 18}O elastic and inelastic scattering were explored. The isotopic differences between the {sup 6,7}Li + {sup 18}O and {sup 6}Li + {sup 16,18}O potential parameters were determined.

  15. Lunar ~3He estimations and related parameters analyses

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    As a potential nuclear fuel, 3He element is significant for both the solution of impending human energy crisis and the conservation of natural environment. Lunar regolith contains abundant and easily extracted 3He. Based on the analyses of the impact factors of 3He abundance, here we have compared a few key assessment parameters and approaches used in lunar regolith 3He reserve estimation and some representative estimation results, and discussed the issues concerned in 3He abundance variation and 3He reserve estimation. Our studies suggest that in a range of at least meters deep, 3He abundance in lunar regolith is homogeneously distributed and generally does not depend on the depth; lunar regolith has long been in a saturation state of 3He trapped by minerals through chemical bonds, and the temperature fluctuation on the lunar surface exerts little influence on the lattice 3He abundance. In terms of above conclusions and the newest lunar regolith depth data from the microwave brightness temperature retrieval of the "ChangE-1" Lunar Microwave Sounder, a new 3He reserve estimation has been presented.

  16. Coulomb Breakup of Nucleus 6 Li on Ion 208Pb

    OpenAIRE

    Irgaziev, B. F.; ERGASHBAEV, H. T.

    1998-01-01

    In the framework of the three-body approach the A(a,bc)A Coulomb breakup has been investigated. The three-body Coulomb dynamic is taken into account to derive the expression for the reaction matrix element. The mechanism of the breakup includes the direct process and the excitation of resonance state of the particle a. The calculation of the triple differential cross section of the 208Pb(6Li, a d)208Pb Coulomb dissociation have been performed in the energy region Ea d < 1MeV. Cal...

  17. Performance Limits of Pulse Tube Cryocoolers Using 3HE

    Science.gov (United States)

    Kittel, P.

    2008-03-01

    The enthalpy, entropy, and exergy flows resulting from the real gas effects of 3He in ideal pulse tube cryocoolers are described. The discussion follows a previous description of the real gas effects of 4He in ideal pulse tube cryocoolers and makes use of a recently developed model of the thermophysical properties of 3He. This model is used to describe how the thermodynamic flows are affected by real gas phenomena of 3He and compares these effects to similar effects for 4He. The analysis was done over the pressure range 0.3-2 MPa and temperatures down to 1 K. At 2 MPa there is almost no difference in the cooling power between 3He and 4He. At lower pressures, using 3He is advantageous. There is a 1-2 K reduction in the 3He cooling power vs. temperature curves compared to those for 4He in the 0.3-1 MPa range.

  18. A Precision Measurement of Nuclear Muon Capture on $^{3}He$

    CERN Document Server

    Ackerbauer, P; Baturin, V N; Beer, G A; Breunlich, W H; Case, T; Crowe, K M; Daniel, H; Deutsch, J; Govaerts, J; Grigoriev, Yu S; Hartmann, F J; Kammel, P; King, R; Lauss, B; Maev, E M; Markushin, V E; Marton, J; Mühlbauer, M; Petitjean, C; Petitjean, T; Petrov, G E; Prieels, R; Prymas, W; Schott, W; Semenchuk, G G; Smirenin, Yu V; Vorobyov, A A; Voropaev, N I; Wojciechowski, P; Grigoriev, Yu.S.; Petitjean, Th.; Smirenin, Yu.V.

    1998-01-01

    The muon capture rate in the reaction mu- 3He -> nu + 3H has been measured at PSI using a modular high pressure ionization chamber. The rate corresponding to statistical hyperfine population of the mu-3He atom is (1496.0 +- 4.0) s^-1. This result confirms the PCAC prediction for the pseudoscalar form factors of the 3He-3H system and the nucleon.

  19. Three-body parameter for Efimov states in 6Li

    Science.gov (United States)

    Huang, Bo; O'Hara, Kenneth M.; Grimm, Rudolf; Hutson, Jeremy M.; Petrov, Dmitry S.

    2014-10-01

    We present a state-of-the-art reanalysis of experimental results on Efimov resonances in the three-fermion system of 6Li. We discuss different definitions of the three-body parameter (3BP) for Efimov states and adopt a definition that excludes effects due to deviations from universal scaling for low-lying states. We develop a finite-temperature model for the case of three distinguishable fermions and apply it to the excited-state Efimov resonance to obtain the most accurate determination to date of the 3BP in an atomic three-body system. Our analysis of ground-state Efimov resonances in the same system yields values for the three-body parameter that are consistent with the excited-state result. Recent work has suggested that the reduced 3BP for atomic systems is a near-universal quantity, almost independent of the particular atom involved. However, the value of the 3BP obtained for 6Li is significantly (˜20 % ) different from that previously obtained from the excited-state resonance in Cs. The difference between these values poses a challenge for theory.

  20. Photoassociative creation of ultracold heteronuclear 6Li40K* molecules

    CERN Document Server

    Ridinger, Armin; Salez, Thomas; Fernandes, Diogo Rio; Bouloufa, Nadia; Dulieu, Olivier; Salomon, Christophe; Chevy, Frederic

    2011-01-01

    We investigate the formation of weakly bound, electronically excited, heteronuclear 6Li40K* molecules by single-photon photoassociation in a magneto-optical trap. We performed trap loss spectroscopy within a range of 325 GHz below the Li(2S_(1/2))+K(4P_(3/2)) and Li(2S_(1/2))+K(4P_(1/2)) asymptotic states and observed more than 60 resonances, which we identify as rovibrational levels of 7 of 8 attractive long-range molecular potentials. The long-range dispersion coefficients and rotational constants are derived. We find large molecule formation rates of up to ~3.5x10^7s^(-1), which are shown to be comparable to those for homonuclear 40K_2*. Using a theoretical model we infer decay rates to the deeply bound electronic ground-state vibrational level X^1\\Sigma^+(v'=3) of ~5x10^4s^(-1). Our results pave the way for the production of ultracold bosonic ground-state 6Li40K molecules which exhibit a large intrinsic permanent electric dipole moment.

  1. Ab initio no-core solutions for $^6$Li

    CERN Document Server

    Shin, Ik Jae; Maris, Pieter; Vary, James P; Forssén, Christian; Rotureau, Jimmy; Michel, Nicolas

    2016-01-01

    We solve for properties of $^6$Li in the ab initio No-Core Full Configuration approach and we separately solve for its ground state and $J^{\\pi}=2_{2}^{+}$ resonance with the Gamow Shell Model in the Berggren basis. We employ both the JISP16 and chiral NNLO$_{opt}$ realistic nucleon-nucleon interactions and investigate the ground state energy, excitation energies, point proton root-mean-square radius and a suite of electroweak observables. We also extend and test methods to extrapolate the ground state energy, point proton root-mean-square radius, and electric quadrupole moment. We attain improved estimates of these observables in the No-Core Full Configuration approach by using basis spaces up through N$_{max}$=18 that enable more definitive comparisons with experiment. Using the Density Matrix Renormalization Group approach with the JISP16 interaction, we find that we can significantly improve the convergence of the Gamow Shell Model treatment of the $^6$Li ground state and $J^{\\pi}=2_{2}^{+}$ resonance by ...

  2. Phenomenological Study of 3He Photodisintegration up to 150 MeV

    Institute of Scientific and Technical Information of China (English)

    WANG Cheng-Bin; ZHU Zhi-Yuan

    2008-01-01

    @@ A parametrization of 3He(γ,p)2H cross section data at laboratory photon energies between 9 and 150MeV is carried out with a simple phenomenological function. The differential cross section data are normalized to the total cross-section values, which are consistent with the measurement from monochromatic photon beams. The obtained results give a good representation of the experimental points.

  3. Solar energetic particle event with He-3/He-4 greater than 1

    Science.gov (United States)

    Balasubrahmanyan, V. K.; Serlemitsos, A. T.

    1974-01-01

    An unusual solar event involving the detection of a He-3/He-4 ratio of about 1.5 was observed with the aid of the cosmic-ray telescopes of OGO-V on May 28, 1969. A theory dealing with the production of H-2, H-3, and He-3 in solar events is considered together with the conditions which would have to be satisfied in order to explain the observed very high helium isotope ratio in terms of the theory.

  4. Hypernuclear spectroscopy of products from 6Li projectiles on a carbon target at 2 AGeV

    CERN Document Server

    Rappold, C; Nakajima, D; Saito, T R; Bertini, O; Bianchin, S; Bozkurt, V; Kavatsyuk, M; Ma, Y; Maas, F; Minami, S; Özel-Tashenov, B; Yoshida, K; Achenbach, P; Ajimura, S; Aumann, T; Gayoso, C Ayerbe; Bhang, H C; Caesar, C; Erturk, S; Fukuda, T; Göküzüm, B; Guliev, E; Hiraiwa, T; Hoffmann, J; Ickert, G; Ketenci, Z S; Khaneft, D; Kim, M; Kim, S; Koch, K; Kurz, N; Fèvre, A Le; Mizoi, Y; Moritsu, M; Nagae, T; Nungesser, L; Okamura, A; Ott, W; Pochodzalla, J; Sakaguchi, A; Sako, M; Schmidt, C J; Sekimoto, M; Simon, H; Sugimura, H; Takahashi, T; Tambave, G J; Tamura, H; Trautmann, W; Voltz, S; Yokota, N; Yoon, C J

    2013-01-01

    A novel experiment, aiming at demonstrating the feasibility of hypernuclear spectroscopy with heavy-ion beams, was conducted. Using the invariant mass method, the spectroscopy of hypernuclear products of 6Li projectiles on a carbon target at 2 AGeV was performed. Signals of the \\Lambda-hyperon and 3\\Lambda H and 4\\Lambda H hypernuclei were observed for final states of p+\\pi^-, 3He+\\pi^- and 4He+\\pi^-, respectively, with significance values of 6.7, 4.7 and 4.9\\sigma. By analyzing the proper decay time from secondary vertex distribution with the unbinned maximum likelihood fitting method, their lifetime values were deduced to be $262 ^{+56}_{-43} \\pm 45$ ps for \\Lambda, $183 ^{+42}_{-32} \\pm 37$ ps for 3\\Lambda H, and $140 ^{+48}_{-33}\\pm 35 $ ps for 4\\Lambda H.

  5. Ions Preheated in 3He-Rich Solar Particle Events

    Institute of Scientific and Technical Information of China (English)

    王德焴

    2003-01-01

    A wave-particle resonance absorption model in the two-ion plasma is suggested in explanation to the coronal ions preheating in 3He-rich solar particle events. It is found that 3He and Fe ions are preferably preheated by the ion-ion hybrid waves at their fundamental and second harmonic ion cyclotron frequencies, respectively.

  6. Efimov Physics in a 6Li-133Cs Atomic Mixture

    Science.gov (United States)

    Johansen, Jacob; Feng, Lei; Parker, Colin; Chin, Cheng; Wang, Yujun

    2015-05-01

    We investigate Efimov physics based on three-body recombination in an atomic mixture of 6Li and 133Cs in the vicinity of interspecies Feshbach resonances at 843 and 889 G. This allows us to compare the loss spectra near different resonances and test the universality of Efimov states. Theoretically the Efimov spectrum near 889 G is expected to be similar to that near 843 G, except that the first resonance is absent near the former Feshbach resonance. This is due to the difference in the Cs-Cs scattering length near the two resonances: At 843 G it is negative, whereas at 889 G it is positive. Although it is primarily the Li-Cs interactions that lead to Efimov resonances, the Cs-Cs scattering length is expected to influence the spectrum. This work is supported by NSF and Chicago MRSEC.

  7. High level of $^3$He polarization of 81\\% Maintained in an on-beam $^3$He spin filter using SEOP

    CERN Document Server

    Babcock, E; Ioe, A

    2010-01-01

    Maintaining high levels of 3He polarization over long periods of time is important to many areas of fundamental and particle beam physics. Long measurement times are often required in such experiments and the data quality is a function of the 3He polarization. This is the case for neutron scattering where the 3He can be used to analyze the spin of a scattered neutron beam and relatively small fluxes of polarized neutrons leads to experiment times longer than several days. Consequently the J\\"ulich Centre for Neutron Science (JCNS) is developing spin-exchange optical pumping (SEOP) systems capable of polarizing the 3He gas in place on a typical neutron instrument. Using a polarizer device we constructed a high level of 3He polarization of 81 % \\pm2% was maintained with good time stability. Such levels of polarization maintained over time will be able to reduce the measurement times for such experiments and eliminate time dependent data corrections.

  8. ^3He neutron spin filters for polarized neutron scattering.

    Science.gov (United States)

    Chen, Wangchun; Borchers, Julie; Chen, Ying; O'Donovan, Kevin; Erwin, Ross; Lynn, Jeffrey; Majkrzak, Charles; McKenney, Sarah; Gentile, Thomas

    2006-03-01

    Polarized neutron scattering (PNS) is a powerful tool that probes the magnetic structures in a wide variety of magnetic materials. Polarized ^3He gas, produced by optical pumping, can be used to polarize or analyze neutron beams because of the strong spin dependence of the neutron absorption cross section for ^3He. Polarized ^3He neutron spin filters (NSF) have been of great interest in PNS community due to recent significant improvement of their performance. Here I will discuss successful applications using ^3He NSFs in polarized neutron reflectometry (PNR) and triple-axis spectrometry (TAS). In PNR, a ^3He NSF in conjunction with a position-sensitive detector allows for efficient polarization analysis of off-specular scattering over a broad range of reciprocal space. In TAS, a ^3He NSF in combination with a double focusing pyrolytic graphite monochromator provides greater versatility and higher intensity compared to a Heusler polarizer. Finally I will present the results from patterned magnetically-coupled thin films in PNR and our first ``proof-of-principle'' experiment in TAS, both of which were performed using ^3He NSF(s) at the NIST Center for Neutron Research.

  9. Solar Source Regions of Energetic 3He Emission

    Science.gov (United States)

    Mason, G. M.; Nitta, N. V.; Cohen, C. M.; Wiedenbeck, M. E.

    2012-12-01

    One of the surprising observations from the ACE mission has been the detection of energetic 3He emission occurring over multi-day periods. Previously observations of solar energetic 3He had detected short-lived "impulsive" energetic particle events which were associated with type III bursts and energetic electrons. The ACE observations were able to detect 3He at very low levels (<1% of 4He compared to ~10% in most earlier work) and this showed that the impulsive events often occurred during seemingly continuous multi-day periods of 3He emission. During solar active periods, 3He was present at 1 AU the majority of the time, giving evidence for either semi-continuous processes or else unresolved multiple small injections. The obvious injections during such periods were strongly associated with jet activity By adding STEREO and SDO observations we are seeking to extend the observational picture for these events. First, by following single 3He emitting regions from STEREO-B to ACE to STEREO-A we seek to examine for how long the 3He emission can continue, since any single spacecraft can be magnetically connected to a single region for only a few days and ACE often sees emission periods of that length. Second, by using SDO-AIA we seek to probe further the properties of the emitting regions to see if the previously reported association with jets is seen in events which we can now observe with greater resolution, sensitivity, and cadence than previously possible.

  10. Cosmogenic and nucleogenic 3He in apatite, titanite, and zircon

    Science.gov (United States)

    Farley, K. A.; Libarkin, J.; Mukhopadhyay, S.; Amidon, W.

    2006-08-01

    Cosmogenic 3He was measured in apatite, titanite, and zircon and cosmogenic 21Ne in quartz at 13 depth intervals in a 2.7-m long drill core in a Miocene ignimbrite from the Altiplano of Bolivia. All three 3He depth profiles as well as the 21Ne profile attenuate exponentially with depth, indicating that both of these isotopes are cosmogenic in origin with no significant contribution from other sources. The attenuation lengthscale for 3He production of Λ = 180 ± 11 g/cm 2 is consistent with expectations for neutron spallation, and is identical to that found for the cosmogenic 21Ne in quartz. By normalizing the measured 3He concentrations to 21Ne and using the independently known cosmogenic 21Ne production rate, the apparent cosmogenic 3He production rates in apatite, titanite, and zircon were respectively found to be 112, 97, and 87 atoms/g/yr at sea-level and high latitude. The formal uncertainty on these estimates is ˜ 20% (2 σ), and arises in equal parts from uncertainties in the measured 3He/ 21Ne ratios and the uncertainty in the 21Ne production rate. However an additional factor affecting the apparent 3He production rate in these phases arises from the long stopping range of spalled 3He and tritium (which decays to 3He). Because all three accessory phases have higher mean atomic number than major rock-forming minerals, they will have lower 3He production rates than their surroundings. As a consequence the long stopping ranges will cause a net implantation of 3He and therefore higher apparent production rates than would apply for purely in-situ production. Thus these apparent production rates apply only to the specific grain sizes analyzed. Analysis of sieved zircon aliquots suggests that a factor of 2 increase in grain size (from ˜ 50 to ˜ 100 μm cross-section) yields a 10% decrease in apparent production rate. While this effect warrants further study, the grain sizes analyzed here are typical of the accessory phases commonly encountered, so the apparent

  11. α and 3He production in the 7Be+28Si reaction at near-barrier energies: Direct versus compound-nucleus mechanisms

    Science.gov (United States)

    Sgouros, O.; Pakou, A.; Pierroutsakou, D.; Mazzocco, M.; Acosta, L.; Aslanoglou, X.; Betsou, Ch.; Boiano, A.; Boiano, C.; Carbone, D.; Cavallaro, M.; Grebosz, J.; Keeley, N.; La Commara, M.; Manea, C.; Marquinez-Duran, G.; Martel, I.; Nicolis, N. G.; Parascandolo, C.; Rusek, K.; Sánchez-Benítez, A. M.; Signorini, C.; Soramel, F.; Soukeras, V.; Stefanini, C.; Stiliaris, E.; Strano, E.; Strojek, I.; Torresi, D.

    2016-10-01

    The production of α and 3He particles, the cluster constituents of 7Be, in the 7Be+28Si reaction was studied at three near-barrier energies, namely 13, 20, and 22 MeV. Angular distribution measurements were performed at each energy, and the data were analyzed in both statistical model and Distorted-Wave Born Approximation (DWBA) frameworks in order to disentangle the degree of competition between direct and compound channels. The energy evolution of the ratio of direct to total reaction cross section was mapped in comparison with similar data for 6Li and 7Li projectiles on a 28Si target. The results indicate larger transfer contributions for collisions involving the mirror nuclei 7Be and 7Li than in the 6Li case. Fusion cross sections were deduced, taking into account the α -particle cross sections due to compound-nucleus formation and particle multiplicities deduced from our statistical model framework. It was found that fusion is compatible with systematics and single-barrier penetration cross sections to within an uncertainty band of 10% to 20%. Indications of fusion hindrance for 7Li and 7Be compared to 6Li, starting from the barrier and below it, are given. This hindrance is attributed to the existence of large transfer channels. Furthermore, the experimental results, analyzed in the DWBA framework, suggest 3He and 4He transfer as the dominant direct reaction mechanism.

  12. Ultrasound Attenuation in Liquid ^3He/High Porosity Aerogel

    Science.gov (United States)

    Choi, H. C.; Mulders, N.

    2005-11-01

    High porosity silica aerogels have been extensively used to study the influence of disorder in p-wave superfluid ^3He. Experimental investigations performed during the last decade revealed three distinct superfluid phases in liquid ^3He /98% aerogel system. The three phases found in this system are called as A, B, and A1-like phases (using the same nomenclature as in the bulk), although only the spin component of the order parameter has been studied and found to resemble that of corresponding bulk phases. A complete understanding of the microscopic structure of the p-wave superfluid phases requires identification of both orbital and spin components of the order parameter. Until now, there is no experimental attempt to directly probe the orbital structure in ^3He/aerogel system. To resolve this issue, we performed acoustic measurements by direct transmission of ultrasound through the ^3He/98% aerogel sample. We will present and discuss our preliminary results.

  13. Polar Phase of Superfluid (3)He in Anisotropic Aerogel.

    Science.gov (United States)

    Dmitriev, V V; Senin, A A; Soldatov, A A; Yudin, A N

    2015-10-16

    We report the first observation of the polar phase of superfluid (3)He. This phase appears in (3)He confined in a new type of aerogel with a nearly parallel arrangement of strands which play the role of ordered impurities. Our experiments qualitatively agree with theoretical predictions and suggest that in other systems with unconventional Cooper pairing (e.g., in unconventional superconductors) similar phenomena may be found in the presence of anisotropic impurities.

  14. Strong-coupling and the Stripe phase of $^3$He

    OpenAIRE

    Wiman, Joshua J.; Sauls, J. A.

    2016-01-01

    Thin films of superfluid $^3$He were predicted, based on weak-coupling BCS theory, to have a stable phase which spontaneously breaks translational symmetry in the plane of the film. This crystalline superfluid, or "stripe" phase, develops as a one dimensional periodic array of domain walls separating degenerate B phase domains. We report calculations of the phases and phase diagram for superfluid $^3$He in thin films using a strong-coupling Ginzburg-Landau theory that accurately reproduces th...

  15. The 3He spectral function in light-front dynamics

    CERN Document Server

    Rinaldi, Matteo; Kaptari, Leonid; Pace, Emanuele; Salmè, Giovanni; Scopetta, Sergio

    2016-01-01

    A distorted spin-dependent spectral function for 3He is considered for the extraction of the transverse-momentum dependent parton distributions in the neutron from semi-inclusive deep inelastic electron scattering off polarized 3He at finite momentum transfers, where final state interactions are taken into account. The generalization of the analysis to a Poincar\\'e covariant framework within the light-front dynamics is outlined.

  16. The 3He spectral function in light-front dynamics

    Directory of Open Access Journals (Sweden)

    Rinaldi Matteo

    2016-01-01

    Full Text Available A distorted spin-dependent spectral function for 3He is considered for the extraction of the transverse-momentum dependent parton distributions in the neutron from semi-inclusive deep inelastic electron scattering off polarized 3He at finite momentum transfers, where final state interactions are taken into account. The generalization of the analysis to a Poincaré covariant framework within the light-front dynamics is outlined.

  17. K^- ^3He and K^+K^- interactions in the reaction pd -> ^3He K^+K^-

    CERN Document Server

    Grishina, V Yu; Kondratyuk, L A

    2006-01-01

    We investigate the K^- ^3He and K^+K^- interactions in the reaction pd -> ^3He K^+K^- near threshold and compare our model calculations with data from the MOMO experiment at COSY-Juelich. The data do not support a strong attraction between the K^- and ^3He system needed for formation of deeply bound K^- nuclear states. We also estimate upper limits for the a_0(980) and f_0(980) contributions to the produced K^+ K^- pairs.

  18. 3-He in the Milky Way Interstellar Medium: Ionization Structure

    CERN Document Server

    Bania, T M; Rood, Robert T; Wilson, T L; LaRocque, Jennifer M

    2007-01-01

    The cosmic abundance of the 3-He isotope has important implications for many fields of astrophysics. We are using the 8.665 GHz hyperfine transition of 3-He+ to determine the 3-He/H abundance in Milky Way HII regions and planetary nebulae. This is one in a series of papers in which we discuss issues involved in deriving accurate 3-He/H abundance ratios from the available measurements. Here we describe the ionization correction we use to convert the 3-He+/H+ abundance, y3+, to the 3-He/H abundance, y3. In principle the nebular ionization structure can significantly influence the y3 derived for individual sources. We find that in general there is insufficient information available to make a detailed ionization correction. Here we make a simple correction and assess its validity. The correction is based on radio recombination line measurements of H+ and 4-He+, together with simple core-halo source models. We use these models to establish criteria that allow us to identify sources that can be accurately corrected...

  19. 6Li/7Li estimates for metal-poor stars

    CERN Document Server

    Perez, A E Garcia; Inoue, S; Ryan, S G; Suzuki, T K; Chiba, M

    2009-01-01

    The presence of the lithium-6 isotope in some metal-poor stars is a matter of surprise because of the high values observed. Non-standard models of Big Bang nucleosynthesis and pre-Galactic cosmic ray fusion and spallation have been proposed to explain these values. However, the observations of this light isotope are challenging which may make some detections disputable. The goal was to determine 6Li/7Li for a sample of metal-poor stars; three of them have been previously studied and the remaining two are new for this type of study. The purpose was to increase, if possible, the number of lithium-6 detections and to confirm previously published results. Spectra of the resonance doublet line of neutral lithium Li I 670.78nm were taken with the High Dispersion Spectrograph at the Subaru 8.2m-telescope for a sample of five metal-poor stars (-3.12 < [Fe/H] < -2.19). The contribution of lithium-6 to the total observed line profile was estimated from the 1D-LTE analysis of the line asymmetry. Observed asymmetri...

  20. All-optical production of 6Li quantum gases

    Science.gov (United States)

    Burchianti, A.; Seman, J. A.; Valtolina, G.; Morales, A.; Inguscio, M.; Zaccanti, M.; Roati, G.

    2015-03-01

    We report efficient production of quantum gases of 6Li using a sub-Doppler cooling scheme based on the D1 transition. After loading in a standard magneto-optical trap, an atomic sample of 109 atoms is cooled at a temperature of 40 μK by a bichromatic D1 gray-molasses. More than 2×107 atoms are then transferred into a high-intensity optical dipole trap, where a two-spin state mixture is evaporatively cooled down to quantum degeneracy. We observe that D1 cooling remains effective in the deep trapping potential, allowing an effective increase of the atomic phase-space density before starting the evaporation. In a total experimental cycle of 11 s, we produce weakly-interacting degenerate Fermi gases of 7×105 atoms at T/TF molecules. We further describe a simple and compact optical system both for high-resolution imaging and for imprinting a thin optical barrier on the atomic cloud; this represents a first step towards the study of quantum tunneling in strongly interacting superfluid Fermi gases.

  1. Ultracold neutron detection with {sup 6}Li-doped glass scintillators. NANOSC: A fast ultracold neutron detector for the nEDM experiment at the Paul Scherrer Institute

    Energy Technology Data Exchange (ETDEWEB)

    Ban, G.; Lefort, T.; Lemiere, Y.; Naviliat-Cuncic, O.; Pierre, E.; Quemener, G.; Rogel, G. [Normandie Univ, ENSICAEN, UNICAEN, CNRS/IN2P3, LPC Caen, Caen (France); Bison, G.; Chowdhuri, Z.; Henneck, R.; Lauss, B.; Mtchedlishvili, A.; Schmidt-Wellenburg, P.; Zsigmond, G. [Paul Scherrer Institute, Villigen-PSI (Switzerland); Bodek, K.; Zejma, J. [Jagiellonian University, Marian Smoluchowski Institute of Physics, Cracow (Poland); Geltenbort, P. [Institut Laue-Langevin, Grenoble (France); Griffith, W.C.; Musgrave, M. [University of Sussex, Falmer, Department of Physics and Astronomy, Brighton (United Kingdom); Helaine, V. [Normandie Univ, ENSICAEN, UNICAEN, CNRS/IN2P3, LPC Caen, Caen (France); Paul Scherrer Institute, Villigen-PSI (Switzerland); Kasprzak, M.; Koss, P.A.; Severijns, N.; Wursten, E. [Katholieke Universiteit Leuven, Instituut voor Kernen Stralingsfysica, Leuven (Belgium); Kermaidic, Y.; Pignol, G.; Rebreyend, D. [LPSC, Universite Grenoble Alpes, CNRS/IN2P3, Grenoble (France); Kirch, K.; Komposch, S.; Krempel, J.; Ries, D. [Paul Scherrer Institute, Villigen-PSI (Switzerland); Institute for Particle Physics, ETH Zuerich, Zuerich (Switzerland); Kozela, A. [Henryk Niedwodniczanski Institute for Nuclear Physics, Cracow (Poland); Piegsa, F.M.; Rawlik, M. [Institute for Particle Physics, ETH Zuerich, Zuerich (Switzerland); Roccia, S. [CSNSM, Universite Paris Sud, CNRS/IN2P3, Orsay (France)

    2016-10-15

    This paper summarizes the results from measurements aiming to characterize ultracold neutron detection with {sup 6}Li-doped glass scintillators. Single GS10 or GS20 scintillators, with a thickness of 100-200μm, fulfill the ultracold neutron detection requirements with an acceptable neutron-gamma discrimination. This discrimination is clearly improved with a stack of two scintillators: a {sup 6}Li-depleted glass bonded to a {sup 6}Li-enriched glass. The technique of optical contact bonding is used between the two glasses in order to eliminate the need for optical glue or grease between them. Relative to a {sup 3}He Strelkov gas detector, the scintillator's detection efficiency is lower for UCN energies close to the scintillator's Fermi potential (85-100 neV), but becomes larger at higher UCN energies. Coupled to a digital data acquisition system, counting rates up to a few 10{sup 5} counts/s can be handled. A detector based on such a scintillator stack arrangement was built and has been used in the neutron electric dipole moment experiment at the Paul Scherrer Institute since 2010. Its response for routine runs of the neutron electric dipole moment experiment is presented. (orig.)

  2. Ultracold neutron detection with 6Li-doped glass scintillators, NANOSC: a fast ultracold neutron detector for the nEDM experiment at the Paul Scherrer Institute

    CERN Document Server

    Ban, G; Bodek, K; Chowdhuri, Z; Geltenbort, P; Griffith, W C; Hélaine, V; Henneck, R; Kasprzak, M; Kermaidic, Y; Kirch, K; Komposch, S; Koss, P A; Kozela, A; Krempel, J; Lauss, B; Lefort, T; Lemière, Y; Mtchedlishvili, A; Musgrave, M; Naviliat-Cuncic, O; Piegsa, F M; Pierre, E; Pignol, G; Quéméner, G; Rawlik, M; Ries, D; Rebreyend, D; Roccia, S; Rogel, G; Schmidt-Wellenburg, P; Severijns, N; Wursten, E; Zejma, J; Zsigmond, G

    2016-01-01

    This paper summarizes the results from measurements aiming to characterize ultracold neutron detection with 6Li-doped glass scintillators. Single GS10 or GS20 scintillators, with a thickness of 100-200 micrometer, fulfill the ultracold neutron detection requirements with an acceptable neutron-gamma discrimination. This discrimination is clearly improved with a stack of two scintillators: a 6Li-depleted glass bonded to a 6Li-enriched glass. The optical contact bonding is used between the scintillators in order to obtain a perfect optical contact. The scintillator's detection efficiency is similar to that of a 3He Strelkov gas detector. Coupled to a digital data acquisition system, counting rates up to a few 10^5 counts/s can be handled. A detector based on such a scintillator stack arrangement was built and has been used in the neutron electric dipole moment experiment at the Paul Scherrer Institute since 2010. Its response for the regular runs of the neutron electric dipole moment experiment is presented.

  3. Ultracold neutron detection with 6Li-doped glass scintillators. NANOSC: A fast ultracold neutron detector for the nEDM experiment at the Paul Scherrer Institute

    Science.gov (United States)

    Ban, G.; Bison, G.; Bodek, K.; Chowdhuri, Z.; Geltenbort, P.; Griffith, W. C.; Hélaine, V.; Henneck, R.; Kasprzak, M.; Kermaidic, Y.; Kirch, K.; Komposch, S.; Koss, P. A.; Kozela, A.; Krempel, J.; Lauss, B.; Lefort, T.; Lemière, Y.; Mtchedlishvili, A.; Musgrave, M.; Naviliat-Cuncic, O.; Piegsa, F. M.; Pierre, E.; Pignol, G.; Quéméner, G.; Rawlik, M.; Ries, D.; Rebreyend, D.; Roccia, S.; Rogel, G.; Schmidt-Wellenburg, P.; Severijns, N.; Wursten, E.; Zejma, J.; Zsigmond, G.

    2016-10-01

    This paper summarizes the results from measurements aiming to characterize ultracold neutron detection with 6Li-doped glass scintillators. Single GS10 or GS20 scintillators, with a thickness of 100-200μm, fulfill the ultracold neutron detection requirements with an acceptable neutron-gamma discrimination. This discrimination is clearly improved with a stack of two scintillators: a 6Li-depleted glass bonded to a 6Li-enriched glass. The technique of optical contact bonding is used between the two glasses in order to eliminate the need for optical glue or grease between them. Relative to a 3He Strelkov gas detector, the scintillator's detection efficiency is lower for UCN energies close to the scintillator's Fermi potential (85-100 neV), but becomes larger at higher UCN energies. Coupled to a digital data acquisition system, counting rates up to a few 105 counts/s can be handled. A detector based on such a scintillator stack arrangement was built and has been used in the neutron electric dipole moment experiment at the Paul Scherrer Institute since 2010. Its response for routine runs of the neutron electric dipole moment experiment is presented.

  4. Polarized (3) He Spin Filters for Slow Neutron Physics.

    Science.gov (United States)

    Gentile, T R; Chen, W C; Jones, G L; Babcock, E; Walker, T G

    2005-01-01

    Polarized (3)He spin filters are needed for a variety of experiments with slow neutrons. Their demonstrated utility for highly accurate determination of neutron polarization are critical to the next generation of betadecay correlation coefficient measurements. In addition, they are broadband devices that can polarize large area and high divergence neutron beams with little gamma-ray background, and allow for an additional spin-flip for systematic tests. These attributes are relevant to all neutron sources, but are particularly well-matched to time of flight analysis at spallation sources. There are several issues in the practical use of (3)He spin filters for slow neutron physics. Besides the essential goal of maximizing the (3)He polarization, we also seek to decrease the constraints on cell lifetimes and magnetic field homogeneity. In addition, cells with highly uniform gas thickness are required to produce the spatially uniform neutron polarization needed for beta-decay correlation coefficient experiments. We are currently employing spin-exchange (SE) and metastability-exchange (ME) optical pumping to polarize (3)He, but will focus on SE. We will discuss the recent demonstration of 75 % (3)He polarization, temperature-dependent relaxation mechanism of unknown origin, cell development, spectrally narrowed lasers, and hybrid spin-exchange optical pumping.

  5. Recurring 3He-rich Solar Energetic Particle Events

    CERN Document Server

    Bucik, R; Mall, U; Korth, A; Mason, G M

    2013-01-01

    Using the SIT instrument aboard STEREO we have examined the abundance of the 3He during the ascending phase of solar cycle 24 from January 2010 through December 2012. We report on several cases when 3He-rich solar energetic particle events were successively observed on ACE and STEREO-A with delays consistent with the Carrington rotation rate. In the investigated period ACE and STEREO-A were significantly separated in the heliolongitude corresponding to solar rotation times of 5 to 10 days. We inspect STEREO-A EUV images and use the potential-field source-surface extrapolations together with in-situ magnetic field data to identify responsible solar sources. We find the 3He/4He ratio highly variable in these events and correlated between the spacecraft for the cases with the same connection region on the Sun.

  6. Strong-Coupling and the Stripe Phase of ^3He

    Science.gov (United States)

    Wiman, Joshua J.; Sauls, J. A.

    2016-09-01

    Thin films of superfluid 3He were predicted, based on weak-coupling BCS theory, to have a stable phase which spontaneously breaks translational symmetry in the plane of the film. This crystalline superfluid, or "stripe" phase, develops as a one-dimensional periodic array of domain walls separating degenerate B phase domains. We report calculations of the phases and phase diagram for superfluid 3He in thin films using a strong-coupling Ginzburg-Landau theory that accurately reproduces the bulk 3He superfluid phase diagram. We find that the stability of the Stripe phase is diminished relative to the A phase, but the Stripe phase is stable in a large range of temperatures, pressures, confinement, and surface conditions.

  7. Evolution of D and $^{3}He$ in the Galaxy

    CERN Document Server

    Tosi, M P

    2000-01-01

    The predictions of Galactic chemical evolution models for D and $^3$He are described in connection with those on the other Galactic quantities for which observational constraints are available. Models in agreement with the largest set of data predict deuterium depletions from the Big Bang to the present epoch smaller than a factor of 3 and do not allow for D/H primordial abundances larger than $\\sim4\\times10^{-5}$. Models predicting higher D consumption do not reproduce other observed features of our Galaxy. If both the primordial D and $^3$He are low, models assuming that 90% of low-mass stars experience an extra-mixing during the red giant phase reproduce all the $^3$He observed abundances. The same percentage allows to fit also the observed carbon isotopic ratios, thus supporting the self-consistency of the extra-mixing mechanism.

  8. Quark-Hadron Duality in Neutron (3He) Spin Structure

    Energy Technology Data Exchange (ETDEWEB)

    Solvignon, Patricia; Liyanage, Nilanga; Chen, Jian-Ping; Choi, Seonho; Aniol, Konrad; Averett, Todd; Boeglin, Werner; Camsonne, Alexandre; Cates, Gordon; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chudakov, Eugene; Craver, Brandon; Cusanno, Francesco; Deur, Alexandre; Dutta, Dipangkar; Ent, Rolf; Feuerbach, Robert; Frullani, Salvatore; Gao, Haiyan; Garibaldi, Franco; Gilman, Ronald; Glashausser, Charles; Gorbenko, Viktor; Hansen, Jens-Ole; Higinbotham, Douglas; Ibrahim, Hassan; Jiang, Xiaodong; Jones, Mark; Kelleher, Aidan; Kelly, J.; Keppel, Cynthia; Kim, Wooyoung; Korsch, Wolfgang; Kramer, Kevin; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Ma, Bin; Margaziotis, Demetrius; Markowitz, Pete; McCormick, Kathy; Meziani, Zein-Eddine; Michaels, Robert; Moffit, Bryan; Monaghan, Peter; Munoz-Camacho, Carlos; Paschke, Kent; Reitz, Bodo; Saha, Arunava; Sheyor, Ran; Singh, Jaideep; Slifer, Karl; Sulkosky, Vince; Sulkosky, Vincent; Sulkosky, Vince; Sulkosky, Vincent; Tobias, William; Urciuoli, Guido; Wang, Kebin; Wijesooriya, Krishni; Wojtsekhowski, Bogdan; Woo, Seungtae; Yang, Jae-Choon; Zheng, Xiaochao; Zhu, Lingyan

    2008-10-01

    We present experimental results of the first high-precision test of quark-hadron duality in the spin-structure function g_1 of the neutron and $^3$He using a polarized 3He target in the four-momentum-transfer-squared range from 0.7 to 4.0 (GeV/c)^2. Global duality is observed for the spin-structure function g_1 down to at least Q^2 = 1.8 (GeV/c)^2 in both targets. We have also formed the photon-nucleon asymmetry A_1 in the resonance region for 3He and found no strong Q^2-dependence above 2.2 (GeV/c)^2.

  9. An Optical Cryostat with $^{3}$He Sorption Refrigerator

    CERN Document Server

    Trofimov, V N; Perminov, V G; Vdovin, V F; Vystavkin, A N

    2005-01-01

    An optical cryostat with $^{3}$He sorption refrigerator is described. The refrigerator is mounted on a copper plate with temperature 4.2 K in vacuum volume of a helium cryostat. It has two sorption steps: the first with working gas $^4$He is intended for condensation of $^{3}$He, the second with $^{3}$He for cooling down to 0.3 K. The cryostat is an independent device that does not contain the external gas communications aimed at reaching low temperatures, and working gases are stored in cans integrated with the cryostat. The refrigerator can be used together with the cryocoolers of Gifford--McMahon or pulse tube types with cooling power not less than 0.3 W/4 K, thus allowing operating without any liquid cryoagents.

  10. Feasibility of neutron diffraction on solid 3He

    Science.gov (United States)

    Siemensmeyer, K.; Schuberth, E. A.; Adams, E. D.; Takano, Y.; Guckelsberger, K.

    2000-07-01

    We have investigated the feasibility of neutron diffraction from solid 3He. The experiment will be performed at the HMI, first aiming for the properties of the antiferromagnetic ordering in the BCC phase and the ferromagnetic order in the HCP phase. Signal and beam heating considerations are essential to account for the enormous neutron absorption cross section of 3He. The study shows that neutron diffraction and transmission experiments are possible, relying on the experience gained from the neutron diffraction experiments on Cu and Ag at nanokelvin temperatures. A pressure cell has been developed which complies with the conflicting demands arising from the neutron and ultralow temperature aspects of the experiment. This work is a first step in an extensive effort to characterize 3He by neutron diffraction.

  11. Light-Front Dynamics and the 3He Spectral Function

    CERN Document Server

    Pace, Emanuele; Kaptari, Leonid; Rinaldi, Matteo; Salme', Giovanni; Scopetta, Sergio

    2016-01-01

    Two topics are presented. The first one is a novel approach for a Poincare' covariant description of nuclear dynamics based on light-front Hamiltonian dynamics. The key quantity is the light-front spectral function, where both normalization and momentum sum rule can be satisfied at the same time. Preliminary results are discussed for an initial analysis of the role of relativity in the EMC effect in 3He. A second issue, very challenging, is considered in a non-relativistic framework, namely a distorted spin-dependent spectral function for 3He in order to take care of the final state interaction between the observed pion and the remnant in semi-inclusive deep inelastic electron scattering off polarized 3He. The generalization of the analysis within the light-front dynamics is outlined.

  12. Anisotropic phases of superfluid ^{3}he in compressed aerogel.

    Science.gov (United States)

    Li, J I A; Zimmerman, A M; Pollanen, J; Collett, C A; Halperin, W P

    2015-03-13

    It has been shown that the relative stabilities of various superfluid states of ^{3}He can be influenced by anisotropy in a silica aerogel framework. We prepared a suite of aerogel samples compressed up to 30% for which we performed pulsed NMR on ^{3}He imbibed within the aerogel. We identified A and B phases and determined their magnetic field-temperature phase diagrams as a function of strain. From these results, we infer that the B phase is distorted by negative strain forming an anisotropic superfluid state more stable than the A phase.

  13. Neutron-scattering experiment on solid 3He

    Science.gov (United States)

    Mat'aš, S.; Bat'ko, I.; Boyko, V.; Schöttl, S.; Siemensmeyer, K.; Raasch, S.; Radulov, I.; Adams, E. D.; Scherline, T. E.

    The central aim of our work is the characterisation of magnetic and crystallographic properties of solid 3He on a microscopic scale. This can only be achieved using neutron-diffraction techniques. The potential of neutron methods in magnetism and their application to nuclear magnetism is well known. They were very successful in the recent investigation of spontaneous nuclear order in copper and silver. The high neutron absorption cross section makes the application of neutron diffraction in solid 3He very difficult - but a careful feasibility study of diffraction experiments shows that new results of fundamental importance in the field of magnetism may be gained.

  14. Dating degassed groundwater with 3H/3He

    NARCIS (Netherlands)

    Visser, A.; Broers, H.P.; Bierkens, M.F.P.

    2007-01-01

    The production of gases in groundwater under contaminated locations by geochemical and biological processes is not uncommon. Degassing of these gases from groundwater and repartitioning of noble gases between water and gas phase distorts groundwater dating by 3H/3He. We observed noble gas concentrat

  15. Conceptual design of the D- sup 3 He reactor artemis

    Energy Technology Data Exchange (ETDEWEB)

    Momoto, H.; Tomita, Y. (National Inst. for Fusion Science, Nagoya (JP)); Ishida, A. (Niigata Univ. (Japan)); Miley, G.H. (Illinois Univ., Urbana, IL (United States)); Kohzaki, Y. (Inst. for Future Technology, Tokyo (JP)); Ohi, S. (Osaka Univ., Suita (Japan)); Ohnishi, M. (Kyoto Univ. (Japan)); Sato, H. (Himeji Inst. of Tech., Hyogo (Japan)); Steinhauer, L.C. (STI Optronics, Inc., Bellevue, WA (US)); Tuszewski, M. (Los Alamos National Lab., NM (United States))

    1992-07-01

    In this paper, a comprehensive design study of the D-{sup 3}He-fueled field-reversed configuration (FRC) reactor Artemis is carried out for the purpose of proving its attractive characteristics and clarifying the critical issues for a commercial fusion reactor. The FRC burning plasma is stabilized and sustained in a steady equilibrium by means of preferential trapping of D-{sup 3}He fusion-produced energetic protons. A novel direct energy converter for 15-MeV protons is also presented. On the basis of consistent fusion plasma production and simple engineering, a compact and simple reactor concept is presented. The D-{sup 3}He FRC power plant offers a most attractive prospect for energy development. It is environmentally acceptable in terms of radioactivity and fuel resources, and the estimated cost of electricity is low compared with a light water reactor. Critical physics and engineering issues in the development of the D-{sup 3}He FRC reactor are clarified.

  16. Modelling two-phase transport of 3H/3He

    NARCIS (Netherlands)

    Visser, A.; Schaap, J.D.; Leijnse, T.; Broers, H.P.; Bierkens, M.F.P.

    2008-01-01

    Degassing of groundwater by excess denitrification of agricultural pollution complicates the interpretation of 3H/3He data and hinders the estimation of travel times in nitrate pollution studies. In this study we used a two-phase flow and transport model (STOMP) to evaluate the method presented by V

  17. The {sup 3}He neutron-spin filter at ILL

    Energy Technology Data Exchange (ETDEWEB)

    Tasset, F.; Heil, W.; Humblot, H.; Lelievre-Berna, E.; Roberts, T. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    Neutron-Spin Filters (NSF) using gaseous polarised {sup 3}He have long been recognised as of enormous potential value in many polarised neutron-scattering applications and, accordingly, ILL started a development programme some years ago. This report gives an account of the present status of the project. (author). 13 refs.

  18. Chiral effective field theory predictions for muon capture on deuteron and $^3$He

    Energy Technology Data Exchange (ETDEWEB)

    Laura E. Marcucci, A. Kievsky, S. Rosati, R. Schiavilla, M. Viviani

    2012-01-01

    The muon-capture reactions {sup 2}H({mu}{sup -}, {nu}{sub {mu}})nn and {sup 3}He({mu}{sup -},{nu}{sub {mu}}){sup 3}H are studied with nuclear strong-interaction potentials and charge-changing weak currents, derived in chiral effective field theory. The low-energy constants (LEC's) c{sub D} and c{sub E}, present in the three-nucleon potential and (c{sub D}) axial-vector current, are constrained to reproduce the A=3 binding energies and the triton Gamow-Teller matrix element. The vector weak current is related to the isovector component of the electromagnetic current via the conserved-vector-current constraint, and the two LEC's entering the contact terms in the latter are constrained to reproduce the A=3 magnetic moments. The muon capture rates on deuteron and {sup 3}He are predicted to be 399 {+-} 3 sec{sup -1} and 1494 {+-} 21 sec{sup -1}, respectively, where the spread accounts for the cutoff sensitivity as well as uncertainties in the LEC's and electroweak radiative corrections. By comparing the calculated and precisely measured rates on {sup 3}He, a value for the induced pseudoscalar form factor is obtained in good agreement with the chiral perturbation theory prediction.

  19. Pressure Dependent Wall Relaxation in Polarized $^3$He Gaseous Cells

    CERN Document Server

    Peng, C; Chu, P -H; Gao, H; Zhang, Y

    2013-01-01

    Pressure dependence of longitudinal relaxation time (T$_1$) due to the cell wall was observed previously at both room temperature and low temperature in valved Rb-coated refillable $^3$He gaseous cells in \\cite{Zheng2}. The diffusion of $^3$He from measurement cell through a capillary tube to the valve and the subsequent depolarization on the surface of the valve was proposed to possibly explain such a pressure dependence at room temperature \\cite{Saam}. In this paper, we investigate this diffusion effect through measurements of T$_1$ with newly designed Rb-coated Pyrex glass cells at 295 K as well as finite element analysis (FEA) studies. Both the experimental results and FEA studies show that the diffusion effect is insufficient to explain the observed linear pressure-dependent behavior of T$_1$.

  20. Acceleration of 3HE and heavy ions at interplanetary shocks

    Science.gov (United States)

    Desai, M. I.; Mason, G. M.; Dwyer, J. R.; Mazur, J. E.; Smith, C. W.; Koug, R. M.

    2001-08-01

    We have surveyed the 0.5-2.0 MeV nucleon-1 ion composition of 56 interplanetary shocks (IP) observed with the Ultra-Low-Energy Isotope Spectrometer (ULEIS) on board the Advanced Composition Explorer (ACE) from 1997 October 1 through 2000 November 30. Our results show the first ever measurement (25 cases) of 3 He ions being accelerated at IP shocks. The 3 He/4 He ratio at the 25 shocks exhibited a wide range of values between 0.00140.24; the ratios were enhanced between factors of ~3-600 over the solar wind value. During the survey period, the occurrence probability of 3 He-rich shocks increased with rising solar activity as measured in terms of the daily occurrence rates of sunspots and X-ray flares. The 3 He enhancements at IP shocks cannot be attributed to rigidity dependent acceleration of solar wind ions and are better explained if the shocks accelerate ions from multiple sources, one being remnant impulsive solar flare material enriched in 3 He ions. Our results also indicate that the contribution of impulsive flares to the seed population for IP shocks varies from event to event, and that the interplanetary medium is being replenished with impulsive material more frequently during periods of increased solar activity. 1. Introduction Enhancements in the intensities of energetic ions associated with transient interplanetary (IP) shocks have been observed routinely at 1 AU since the 1960's (e.g., Reames 1999). It is presently believed that the majority of such IP shocks are driven by fast coronal mass ejections or CMEs as they propagate through interplanetary space (e.g., Gosling 1993), and that the associated ion intensity enhancements are due to diffusive shock acceleration of solar wind ions (Lee 1983; Jones and Ellison 1991; Reames 1999). However, the putative solar wind origin of the IP-shock accelerated ions is based on composition measurements associated with a very limited number of individual IP shocks (Klecker et al. 1981; Hovestadt et al. 1982; Tan et

  1. Proton polarization from π+ absorption in 3He

    Science.gov (United States)

    Maytal-Beck, S.; Aclander, J.; Altman, A.; Ashery, D.; Hahn, H.; Moinester, M. A.; Rahav, A.; Feltham, A.; Jones, G.; Pavan, M.; Sevior, M.; Hutcheon, D.; Ottewell, D.; Smith, G. R.; Niskanen, J. A.

    1992-05-01

    We present the first polarization measurements for pion absorption on a nucleus heavier than the deuteron. The polarization of protons resulting from π+ absorption in the 3He was measured at bombarding energies of 120 and 250 MeV. Protons from absorption in a quasideuteron were selected by applying kinematical constraints. A significant discrepancy was observed between the experimental results and theoretical predictions. At 120 MeV the measured polarizations for 3He are consistent with those of the deuteron. At 250 MeV the angular distribution of the polarization is significantly different than for the deuteron, showing sensitivity to the nuclear density, and thus may be sensitive to short range correlations between nucleons.

  2. Nuclear (K) Bound States in 4He and 3He

    Institute of Scientific and Technical Information of China (English)

    LI Yi-He; WU Shi-Shu

    2009-01-01

    @@ We construct a phenomenological K N interaction which reproduces the two resonances: the energy of the first resonance is 1420MeV and the other is 1392MeV. The A(1405) is found by a superposition of the two reso-nances with appropriate weights. Within the framework of the Brueckner-Hartree-Fock theory, we have studied K- - 3He(T=0) and K- - 4He(T=1/2). The binding energy BK-is 93MeV(72MeV) and the width F is 13 MeV(25 MeV) for K- - 3He(T=0) (K- - 4He(T=1/2)).

  3. Neutron spectrometry using artificial neural networks for a Bonner sphere spectrometer with a {sup 3}He detector

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz R, J. M. [Universidad Autonoma de Zacatecas, Unidad Academica de Ingenieria Electrica, Apdo. Postal 336, 98000 Zacatecas (Mexico); Martinez B, M. R.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico); Gallego D, E.; Lorente F, A. [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, ETSI Industriales, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Mendez V, R.; Los Arcos M, J. M.; Guerrero A, J. E., E-mail: morvymm@yahoo.com.m [CIEMAT, Laboratorio de Metrologia de Radiaciones Ionizantes, Avda. Complutense 22, 28040 Madrid (Spain)

    2011-02-15

    Neutron spectra unfolding and dose equivalent calculation are complicated tasks in radiation protection, are highly dependent of the neutron energy, and a precise knowledge on neutron spectrometry is essential for all dosimetry-related studies as well as many nuclear physics experiments. In previous works have been reported neutron spectrometry and dosimetry results, by using the artificial neural networks (Ann) technology as alternative solution, starting from the count rates of a Bonner spheres system with a {sup 6}LiI(Eu) thermal neutrons detector, 7 polyethylene spheres and the UTA4 response matrix with 31 energy bins. In this work, an Ann was designed and optimized by using the RDAnn methodology for the Bonner spheres system used at CIEMAT Spain, which is composed of a {sup 3}He neutron detector, 12 moderator spheres and a response matrix for 72 energy bins. For the Ann design process a neutrons spectra catalogue compiled by the IAEA was used. From this compilation, the neutrons spectra were converted from lethargy to energy spectra. Then, the resulting energy fluence spectra were re-bin ned by using the MCNP code to the corresponding energy bins of the {sup 3}He response matrix before mentioned. With the response matrix and the re-bin ned spectra the counts rate of the Bonner spheres system were calculated and the resulting re-bin ned neutrons spectra and calculated counts rate were used as the Ann training data set. (Author)

  4. Internal Magnus effects in superfluid 3He-A

    Science.gov (United States)

    Salmelin, R. H.; Salomaa, M. M.; Mineev, V. P.

    The orbital angular momentum of the coherently aligned Cooper pairs in superfluid (3)He-A is transmitted to an object immersed in the condensate. The authors evaluate the quasiparticle-scattering asymmetry experienced by a negative ion; this leads to a measurable, purely quantum-mechanical Magnus force deflecting the ion's trajectory. Close to T(sub c), possible hydrodynamic Magnus effects are smaller by the factor delta sub A/(k sub B)(T sub c).

  5. Hard Two-body Photodisintegration of 3He

    CERN Document Server

    Pomerantz, I; Gilman, R; Higinbotham, D W; Piasetzky, E; Strauch, S; Adhikari, K P; Aghasyan, M; Allada, K; Amaryan, M J; Pereira, S Anefalos; Anghinolfi, M; Baghdasaryan, H; Ball, J; Baltzell, N A; Battaglieri, M; Batourine, V; Beck, A; Beck, S; Bedlinskiy, I; Berman, B L; Biselli, A S; Boeglin, W; Bono, J; Bookwalter, C; Boiarinov, S; Briscoe, W J; Brooks, W K; Bubis, N; Burkert, V; Camsonne, A; Canan, M; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Chirapatpimol, K; Cisbani, E; Cole, P L; Contalbrigo, M; Crede, V; Cusanno, F; D'Angelo, A; Daniel, A; Dashyan, N; de Jager, C W; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Dodge, G E; Doughty, D; Dupre, R; Dutta, C; Egiyan, H; Alaoui, A El; Fassi, L El; Eugenio, P; Fedotov, G; Fegan, S; Fleming, J A; Fradi, A; Garibaldi, F; Geagla, O; Gevorgyan, N; Giovanetti, K L; Girod, F X; Glister, J; Goetz, J T; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Harrison, N; Heddle, D; Hicks, K; Ho, D; Holtrop, M; Hyde, C E; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jiang, X; Jo, H S; Joo, K; Katramatou, A T; Keller, D; Khandaker, M; Khetarpal, P; Khrosinkova, E; Kim, A; Kim, W; Klein, F J; Koirala, S; Kubarovsky, A; Kubarovsky, V; Kuleshov, S V; Kvaltine, N D; Lee, B; LeRose, J J; Lewis, S; Lindgren, R; Livingston, K; Lu, H Y; MacGregor, I J D; Mao, Y; Martinez, D; Mayer, M; McCullough, E; McKinnon, B; Meekins, D; Meyer, C A; Michaels, R; Mineeva, T; Mirazita, M; Moffit, B; Mokeev, V; Montgomery, R A; Moutarde, H; Munevar, E; Camacho, C Munoz; Nadel-Turonski, P; Nasseripour, R; Nepali, C S; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Pappalardo, L L; Paremuzyan, R; Park, K; Park, S; Petratos, G G; Phelps, E; Pisano, S; Pogorelko, O; Pozdniakov, S; Procureur, S; Protopopescu, D; Puckett, A J R; Qian, X; Qiang, Y; Ricco, G; Rimal, D; Ripani, M; Ritchie, B G; Rodriguez, I; Ron, G; Rosner, G; Rossi, P; Sabatie, F; Saha, A; Saini, M S; Sarty, A J; Sawatzky, B; Saylor, N A; Schott, D; Schulte, E; Schumacher, R A; Seder, E; Seraydaryan, H; Shneor, R; Smith, G D; Sokhan, D; Sparveris, N; Stepanyan, S S; Stepanyan, S; Stoler, P; Subedi, R; Sulkosky, V; Taiuti, M; Tang, W; Taylor, C E; Tkachenko, S; Ungaro, M; Vernarsky, B; Vineyard, M F; Voskanyan, H; Voutier, E; Walford, N K; Wang, Y; Watts, D P; Weinstein, L B; Weygand, D P; Wojtsekhowski, B; Wood, M H; Yan, X; Yao, H; Zachariou, N; Zhan, X; Zhang, J; Zhao, Z W; Zheng, X; Zonta, I

    2013-01-01

    We have measured cross sections for the gamma+3He->p+d reaction at photon energies of 0.4 - 1.4 GeV and a center-of-mass angle of 90 deg. We observe dimensional scaling above 0.7 GeV at this center-of-mass angle. This is the first observation of dimensional scaling in the photodisintegration of a nucleus heavier than the deuteron.

  6. Polarized 3 He Spin Filters for Slow Neutron Physics

    OpenAIRE

    Gentile, T. R.; W.C. Chen; Jones, G. L.; Babcock, E.; Walker, T. G.

    2005-01-01

    Polarized 3He spin filters are needed for a variety of experiments with slow neutrons. Their demonstrated utility for highly accurate determination of neutron polarization are critical to the next generation of betadecay correlation coefficient measurements. In addition, they are broadband devices that can polarize large area and high divergence neutron beams with little gamma-ray background, and allow for an additional spin-flip for systematic tests. These attributes are relevant to all neut...

  7. Hard Photodisintegration of 3He into pd pair

    CERN Document Server

    Maheswari, Dhiraj

    2016-01-01

    The recent measurements of high energy photodisintegration of the $^3He$ nucleus to the $pd$ pair at $90^0$ center of mass demonstrated an energy scaling consistent with the quark counting rule with unprecedentedly large exponent of $s^{-17}$. To understand the underlying mechanism of this process we extended the theoretical formalism of hard rescattering mechanism to calculate the $\\gamma ^3He\\rightarrow pd$ reaction. In HRM the incoming high energy photon strikes a quark from one of the nucleons in the target which subsequently undergoes hard rescattering with the quarks from the other nucleons generating hard two-body system in the final state of the reaction. Within the HRM we derived the parameter free expression for the differential cross section of the reaction, which is expressed through the $^3He\\rightarrow pd$ transition spectral function, cross section of hard $pd\\rightarrow pd$ scattering and the effective charge of the quarks being interchanged during the hard rescattering process. The numerical ...

  8. Resonant quasiparticle-ion scattering in anisotropic superfluid 3He

    Science.gov (United States)

    Salmelin, R. H.; Salomaa, M. M.

    1990-03-01

    Low-energy excitations in quantum fluids are most directly encountered by ions. In the superfluid phases of 3He the relevant elementary excitations are Bogoliubov quasiparticles, which undergo repeated scattering off an ion in the presence of a divergent density of states. We present a quantum-mechanical calculation of the resonant 3He quasiparticle-scattering-limited mobility for negative ions in the anisotropic bulk 3A (A phase) and 3P (polar phase) that is exact when the quasiparticles scatter elastically. We develop a numerical scheme to solve the singular equations for quasiparticle-ion scattering in the A and P phases. Both of these superfluid phases feature a uniaxially symmetric order parameter but distinct topology for the magnitude of the energy gap on the Fermi sphere, i.e., points versus lines of nodes. In particular, the perpetual orbital circulation of Cooper pairs in 3A results in a novel, purely quantum-mechanical intrinsic Magnus effect, which is absent in the polar phase, where Cooper pairs possess no spontaneous orbital angular momentum. This is of interest also for transport properties of heavy-fermion superconductors. We discuss the 3He quasiparticle-ion cross sections, which allow one to account for the mobility data with essentially no free parameters. The calculated mobility thus facilitates an introduction of ``ion spectroscopy'' to extract useful information on fundamental properties of the superfluid state, such as the temperature dependence of the energy gap in 3A.

  9. Search for the Halo Effect in the 1H(6He, 6Li)n Peaction

    Institute of Scientific and Technical Information of China (English)

    李志宏; 柳卫平; 白希祥; 王友宝; 连钢; 李志常; 申庆彪; 林承键; 曾晟; 符长波

    2002-01-01

    The angular distributions of the charge exchange reaction 1 H(6He, 6Li)n were measured in reverse kinematics with a secondary 6He beam at the energy of4.17 AMeV. The data were analysed in the context ora microscopic calculation. It is shown that both the ground state of6He and the second excited state of6Li (3.563 MeV, 0+) have a halo structure.

  10. 6LiF oleic acid capped nanoparticles entrapment in siloxanes for thermal neutron detection

    Science.gov (United States)

    Carturan, S.; Maggioni, G.; Marchi, T.; Gramegna, F.; Cinausero, M.; Quaranta, A.; Palma, M. Dalla

    2016-07-01

    The good light output of siloxane based scintillators as displayed under γ-rays and α particles has been exploited here to obtain clear and reliable response toward thermal neutrons. Sensitization towards thermal neutrons has been pursued by adding 6LiF, in form of nanoparticles. Aiming at the enhancement of compatibility between the inorganic nanoparticles and the low polarity, siloxane based surrounding medium, oleic acid-capped 6LiF nanoparticles have been synthesized by thermal decomposition of Li trifluoroacetate. Thin pellets siloxane scintillator maintained their optical transmittance up to weight load of 2% of 6Li. Thin samples with increasing 6Li concentration and thicker ones with fixed 6Li amount have been prepared and tested with several sources (α, γ-rays, moderated neutrons). Light output as high as 80% of EJ212 under α irradiation was measured with thin samples, and negligible changes have been observed as a result of 6LiF addition. In case of thick samples, severe light loss has been observed, as induced by opacity. Nevertheless, thermal neutrons detection has been assessed and the data have been compared with GS20, based on Li glass, taken as a reference material.

  11. Precision study of the eta-3He system using the d+p->3He+eta reaction

    CERN Document Server

    Mersmann, T; Chiladze, D; Dymov, S; Hartmann, M; Hejny, V; Kacharava, A K; Keshelashvili, I; Khoukaz, A; Kulessa, P; Maeda, Y; Mielke, M; Mikirtychiants, S; Ohm, H; Papenbrock, M; Prasuhn, D; Rathmann, F; Rausmann, T; Schleichert, R; Serdyuk, V; Stein, H J; Ströher, H; Täschner, A; Valdau, Y; Wilkin, C; Wro'nska, A; Valdau, Yu.

    2007-01-01

    The differential and total cross sections for the d+p->3He+eta reaction have been measured in a high precision high statistics COSY-ANKE experiment near threshold using a continuous beam energy ramp up to an excess energy Q of 11.3 MeV with essentially 100% acceptance. The kinematics allowed the mean value of Q to be determined to about 9 keV. Evidence is found for the effects of higher partial waves for Q>4 MeV. The very rapid rise of the total cross section to its maximum value within 0.5 MeV of threshold implies a very large eta-3He scattering length and hence the presence of a quasi-bound state extremely close to threshold.

  12. Hypernuclear spectroscopy of products from {sup 6}Li projectiles on a carbon target at 2A GeV

    Energy Technology Data Exchange (ETDEWEB)

    Rappold, C., E-mail: c.rappold@gsi.de [Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany); GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Kim, E. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Seoul National University, Gwanakro Sillim-dong, Gwanak-gu, Seoul 151-747 (Korea, Republic of); Nakajima, D. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Saito, T.R., E-mail: t.saito@gsi.de [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Johannes Gutenberg-Universität Mainz, J.J. Becherweg 40, 55099 Mainz (Germany); The Helmholtz Institute Mainz (HIM), J.J. Becherweg 40, 55099 Mainz (Germany); Bertini, O. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Johannes Gutenberg-Universität Mainz, J.J. Becherweg 40, 55099 Mainz (Germany); Bianchin, S. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Bozkurt, V. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Nigde University, 51100 Nigde (Turkey); Kavatsyuk, M. [KVI, University of Groningen, Zernikelaan 25, NL-9747 AA Groningen (Netherlands); Ma, Y. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Johannes Gutenberg-Universität Mainz, J.J. Becherweg 40, 55099 Mainz (Germany); Maas, F. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Johannes Gutenberg-Universität Mainz, J.J. Becherweg 40, 55099 Mainz (Germany); The Helmholtz Institute Mainz (HIM), J.J. Becherweg 40, 55099 Mainz (Germany); and others

    2013-09-02

    A novel experiment, aiming at demonstrating the feasibility of hypernuclear spectroscopy with heavy ion beams, was conducted. Using the invariant mass method, the spectroscopy of hypernuclear products of {sup 6}Li projectiles on a carbon target at 2A GeV was performed. Signals of the Λ-hyperon and {sup 3}{sub Λ}H and {sup 4}{sub Λ}H hypernuclei were observed for final states of p+π{sup −}, {sup 3}He+π{sup −} and {sup 4}He+π{sup −}, respectively, with significance values of 6.7, 4.7 and 4.9σ. By analyzing the proper decay time from secondary vertex distribution with the unbinned maximum likelihood fitting method, their lifetime values were deduced to be 262{sub −43}{sup +56}±45 ps for Λ, 183{sub −32}{sup +42}±37 ps for {sup 3}{sub Λ}H, and 140{sub −33}{sup +48}±35 ps for {sup 4}{sub Λ}H.

  13. Relaxation of Spin Polarized $^3$He in Mixtures of $^3$He and $^4$He at $\\sim$330 mK

    CERN Document Server

    Ye, Q; Zheng, W; Dutta, D; Dubose, F; Golub, R; Huffman, P; Swank, C; Korobkina, E; 10.1103/PhysRevA.80.023403

    2009-01-01

    We report the measurements of depolarization probabilities of polarized $^3$He in a rectangular acrylic cell with a deuterated tetraphenyl butadiene-doped deuterated polystyrene coating filled with superfluid $^4$He at $\\sim$330 mk with a magnetic holding field of $\\sim$7.3 G. We achieve a wall depolarization probability of $\\sim1.0\\times10^{-7}$. Such a surface will find application in a new experiment searching for the neutron electric dipole moment and other applications.

  14. Pion absorption on 3He at low energies

    Science.gov (United States)

    Hahn, H.; Altman, A.; Ashery, D.; Gefen, G.; Gill, D. R.; Johnson, R. R.; Levy-Nathansohn, R.; Moinester, M. A.; Sevior, M.; Trelle, R. P.

    1996-03-01

    The reactions 3He(π+,pp)p and 3He(π-,pn)n were studied at 37.0 MeV by coincidence detection of two nucleons. The differential cross sections were separated to two-nucleon (σ2N), three-nucleon (σ3N), and final-state interaction (σFSI) components. For π+, the σ2N angular distribution is symmetric about 90°, and the total cross section is 1.5 times the cross section measured for d(π+,pp). For π-, the angular distribution is asymmetric (backward peaked). The asymmetry increases with decreasing energy, indicating increasing pion s-wave contribution at lower energies. The fraction of the cross section induced by s-wave pions as calculated by a partial wave amplitude analysis is 13%. The measured total cross sections are σ2N(π-)=0.85+/-0.08 mb and σ2N(π+)=7.9+/-0.5 mb; σ3N(π-)=1.6+/-0.7 mb and σ3N(π+)=1.3+/-0.3 mb. A new evaluation of σ3N at Tπ=62.5 and 82.8 MeV is given, using data from an earlier experiment. The cross sections leading to the two-nucleon final-state interaction at Tπ=37.0 MeV are also estimated.

  15. The 3H-3He Charge Radii Difference

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Luke S. [Bluffton University, Bluffton, OH; Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Arrington, John R. [Argonne National Lab. (ANL), Argonne, IL (United States); Higinbotham, Douglas W. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-03-01

    The upcoming E12-14-009 [1] experiment at Jefferson Lab will determine the ratio of the electric form factors for the A=3 mirror nuclei 3He and 3H. The measurement will use a 1.1 GeV electron beam, a special collimator plate to allow for simultaneous optics measurements, and the low-activity tritium target being prepared for Jefferson Lab. By observing the dependence of the form factor ratio as a function of Q2 over 0.05–0.09 GeV2, the dependence of the radii extraction on the shape of the form factors is minimized. As a result, we anticipate the uncertainty of the extracted charge radii difference to be 0.03 fm, a reduction of 70% from the current measurement. Using precise measurements of the 3He charge radius from isotopic shift or μHe measurements [2–4], we can deduce the absolute 3H charge radius. The results will provide a direct comparison to recent calculations of the charge radii.

  16. Hard photodisintegration of a proton pair in {sup 3}He

    Energy Technology Data Exchange (ETDEWEB)

    Stanley Brodsky; Leonid Frankfurt; Ronald Gilman; J. R. Hiller; G. A. Miller; Eliezer Piasetzky; Misak Sargsian; Mark Strikman

    2003-05-01

    Hard photodisintegration of the deuteron has been extensively studied in order to understand the dynamics of the transition from hadronic to quark-gluon descriptions of the strong interaction. In this work, we discuss the extension of this program to hard photodisintegration of a pp pair in the {sup 3}He nucleus. Experimental confirmation of new features predicted here for the suggested reaction would advance our understanding of hard nuclear reactions. A main prediction, in contrast with low-energy observations, is that the pp breakup cross section is not much smaller than the one for pn break up. In some models, the energy-dependent oscillations observed for pp scattering are predicted to appear in the {gamma} {sup 3}He {yields} pp + n reaction. Such an observation would open up a completely new field in studies of color coherence phenomena in hard nuclear reactions. We also demonstrate that, in addition to the energy dependence, the measurement of the light-cone momentum distribution of the recoil neutron provides an independent test of the underlying dynamics of hard disintegration.

  17. The 3H–3He Charge Radii Difference

    Directory of Open Access Journals (Sweden)

    Myers L. S.

    2016-01-01

    Full Text Available The upcoming E12-14-009 [1] experiment at Jefferson Lab will determine the ratio of the electric form factors for the A=3 mirror nuclei 3He and 3H. The measurement will use a 1.1 GeV electron beam, a special collimator plate to allow for simultaneous optics measurements, and the low-activity tritium target being prepared for Jefferson Lab. By observing the dependence of the form factor ratio as a function of Q2 over 0.05–0.09 GeV2, the dependence of the radii extraction on the shape of the form factors is minimized. As a result, we anticipate the uncertainty of the extracted charge radii difference to be 0.03 fm, a reduction of 70% from the current measurement. Using precise measurements of the 3He charge radius from isotopic shift or μHe measurements [2–4], we can deduce the absolute 3H charge radius. The results will provide a direct comparison to recent calculations of the charge radii.

  18. Determining the 6Li Doped Side of a Glass Scintillator for Ultra Cold Neutrons

    CERN Document Server

    Jamieson, Blair

    2015-01-01

    Ultracold neutron (UCN) detectors using two visually very similar, to the microscopic level, pieces of optically contacted Cerium doped lithium glasses have been proposed for high rate UCN experiments. The chief difference between the two glass scintillators is that one side is 6Li depleted and the other side Li doped. This note outlines a method to determine which side of the glass stack is doped with 6Li using AmBe and 252Cf neutron sources, and a Si surface barrier detector. The method sees an excess of events around the alpha and triton energies of neutron capture on 6Li when the enriched side is facing the Si surface barrier detector.

  19. Fermion Monte Carlo Calculations on Liquid-3He

    Energy Technology Data Exchange (ETDEWEB)

    Kalos, M H; Colletti, L; Pederiva, F

    2004-03-16

    Methods and results for calculations of the ground state energy of the bulk system of {sup 3}He atoms are discussed. Results are encouraging: they believe that they demonstrate that their methods offer a solution of the ''fermion sign problem'' and the possibility of direct computation of many-fermion systems with no uncontrolled approximations. Nevertheless, the method is still rather inefficient compared with variational or fixed-node approximate methods. There appears to be a significant populations size effect. The situation is improved by the inclusion of ''Second Stage Importance Sampling'' and of ''Acceptance/Rejection'' adapted to their needs.

  20. APT {sup 3}He target/blanket. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-01

    The {sup 3}He target/blanket (T/B) preconceptual design for the 3/8-Goal facility is based on a 1000-MeV, 200-mA accelerator to produce a high-intensity proton beam that is expanded and then strikes one of two T/B modules. Each module consists of a centralized neutron source made of tungsten and lead, a proton beam backstop region made of zirconium and lead, and a moderator made of D{sub 2}O. Helium-3 gas is circulated through the neutron source region and the blanket to create tritium through neutron capture. The gas is continually processed to extract the tritium with an online separation process.

  1. X-rays from antiprotonic3He and4He

    Science.gov (United States)

    Schneider, M.; Bacher, R.; Blüm, P.; Gotta, D.; Heitlinger, K.; Kunold, W.; Rohmann, D.; Egger, J.; Simons, L. M.; Elsener, K.

    1991-06-01

    Antiprotonic X-rays from the helium isotopes have been observed at pressures of 36, 72, 375 and 600 mbar. The antiproton beam from LEAR with momenta of 309 and 202 MeV/c has been stopped at these pressures using the cyclotron trap. The X-rays were detected with Si (Li) and intrinsic Ge semiconductor detectors. Absolute X-ray yields were determined and the strong-interaction 2p shifts and the 2p and 3d broadenings measured to be ɛ2p=(-17±4) eV, Γ2p=(25±9) eV and Γ3d=(2.14 ±0.18) meV for ¯p3He and ɛ2p=(-18±2) eV, Γ2p =(45±5) eV and Γ3d=(2.36±0.10) meV for ¯p4He.

  2. Event identification in 3He proportional counters using risetime discrimination

    Science.gov (United States)

    Langford, T. J.; Bass, C. D.; Beise, E. J.; Breuer, H.; Erwin, D. K.; Heimbach, C. R.; Nico, J. S.

    2013-07-01

    We present a straightforward method for particle identification and background rejection in 3He proportional counters for use in neutron detection. By measuring the risetime and pulse height of the preamplifier signals, one may define a region in the risetime versus pulse height space where the events are predominately from neutron interactions. For six proportional counters surveyed in a low-background environment, we demonstrate the ability to reject alpha-particle events with an efficiency of 99%. By applying the same method, we also show an effective rejection of microdischarge noise events that, when passed through a shaping amplifier, are indistinguishable from physical events in the counters. The primary application of this method is in measurements where the signal-to-background for counting neutrons is very low, such as in underground laboratories.

  3. Event Identification in $^3$He Proportional Counters Using Risetime Discrimination

    CERN Document Server

    Langford, T J; Beise, E J; Breuer, H; Erwin, D K; Heimbach, C R; Nico, J S

    2012-01-01

    We present a straightforward method for particle identification and background rejection in $^3$He proportional counters for use in neutron detection. By measuring the risetime and pulse height of the preamplifier signals, one may define a region in the risetime versus pulse height space where the events are predominately from neutron interactions. For six proportional counters surveyed in a low-background environment, we demonstrate the ability to reject alpha-particle events with an efficiency of 99%. By applying the same method, we also show an effective rejection of microdischarge noise events that, when passed through a shaping amplifier, are indistinguishable from physical events in the counters. The primary application of this method is in measurements where the signal-to-background for counting neutrons is very low, such as in underground laboratories.

  4. Pion absorption on {sup 3}He at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, H.; Altman, A.; Ashery, D.; Gefen, G.; Gill, D.R.; Johnson, R.R.; Levy-Nathansohn, R.; Moinester, M.A.; Sevior, M.; Trelle, R.P. [Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel Aviv University, 69978 Ramat Aviv (Israel)]|[TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (CANADA)]|[Department of Physics, University of British Columbia, Vancouver, British Columbia, V6T 2A6 (CANADA)

    1996-03-01

    The reactions {sup 3}He({pi}{sup +},{ital pp}){ital p} and {sup 3}He({pi}{sup {minus}},{ital pn}){ital n} were studied at 37.0 MeV by coincidence detection of two nucleons. The differential cross sections were separated to two-nucleon ({sigma}{sub 2{ital N}}), three-nucleon ({sigma}{sub 3{ital N}}), and final-state interaction ({sigma}{sub FSI}) components. For {pi}{sup +}, the {sigma}{sub 2{ital N}} angular distribution is symmetric about 90{degree}, and the total cross section is 1.5 times the cross section measured for {ital d}({pi}{sup +},{ital pp}). For {pi}{sup {minus}}, the angular distribution is asymmetric (backward peaked). The asymmetry increases with decreasing energy, indicating increasing pion {ital s}-wave contribution at lower energies. The fraction of the cross section induced by {ital s}-wave pions as calculated by a partial wave amplitude analysis is 13{percent}. The measured total cross sections are {sigma}{sub 2{ital N}}({pi}{sup {minus}})=0.85{plus_minus}0.08 mb and {sigma}{sub 2{ital N}}({pi}{sup +})=7.9{plus_minus}0.5 mb; {sigma}{sub 3{ital N}}({pi}{sup {minus}})=1.6{plus_minus}0.7 mb and {sigma}{sub 3{ital N}}({pi}{sup +})=1.3{plus_minus}0.3 mb. A new evaluation of {sigma}{sub 3{ital N}} at {ital T}{sub {pi}}=62.5 and 82.8 MeV is given, using data from an earlier experiment. The cross sections leading to the two-nucleon final-state interaction at {ital T}{sub {pi}}=37.0 MeV are also estimated. {copyright} {ital 1996 The American Physical Society.}

  5. Properties of 4He and 6Li with improved chiral EFT interactions

    Science.gov (United States)

    Maris, P.; Binder, S.; Calci, A.; Epelbaum, E.; Furnstahl, R. J.; Golak, J.; Hebeler, K.; Kamada, H.; Krebs, H.; Langhammer, J.; Liebig, S.; Meißner, U.-G.; Minossi, D.; Nogga, A.; Potter, H.; Roth, R.; Skibiński, R.; Topolnicki, K.; Vary, J. P.; Witala, H.

    2016-03-01

    We present recent results for 4He and 6Li obtained with improved NN interactions derived from chiral effective field theory up to N4LO. The many-body calculations are performed order-by-order in the chiral expansion. At N3LO and N4LO additional renormalization using the Similarity Renormalization Group is adopted to improve numerical convergence of the many-body calculations. We discuss results for the ground state energies, as well as the magnetic moment and the low-lying spectrum of 6Li.

  6. Properties of 4He and 6Li with improved chiral EFT interactions

    Directory of Open Access Journals (Sweden)

    Maris P.

    2016-01-01

    Full Text Available We present recent results for 4He and 6Li obtained with improved NN interactions derived from chiral effective field theory up to N4LO. The many-body calculations are performed order-by-order in the chiral expansion. At N3LO and N4LO additional renormalization using the Similarity Renormalization Group is adopted to improve numerical convergence of the many-body calculations. We discuss results for the ground state energies, as well as the magnetic moment and the low-lying spectrum of 6Li.

  7. Cosmic Ray Production of $^6$Li by Structure Formation Shocks in the Early Galaxy

    CERN Document Server

    Inoue, S; Inoue, Susumu; Suzuki, Takeru Ken

    2003-01-01

    We discuss the production of the element $^6$Li in the early Galaxy by cosmic rays accelerated at structure formation shocks, driven by the hierarchical merging of sub-Galactic halos during Galaxy formation. The salient features of this scenario are discussed and compared with observations of $^6$Li in metal-poor halo stars, including a recent Subaru HDS result on the star HD140283. Some unique predictions of the model are clearly testable by future observations and may also provide important insight into how the Galaxy formed.

  8. Basic technology for {sup 6}Li enrichment using an ionic-liquid impregnated organic membrane

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Tsuyoshi, E-mail: hoshino.tsuyoshi@jaea.go.jp [Blanket Irradiation and Analysis Group, Fusion Research and Development Directorate, Japan Atomic Energy Agency, 4002, Narita-cho, Oarai-machi, Higashi Ibaraki-gun, Ibaraki 311-1393 (Japan); Terai, Takayuki [The Institute of Engineering Innovation and Department of Nuclear Engineering and Management School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2011-10-01

    The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 ({sup 6}Li) in tritium breeding materials. However, natural Li contains only about 7.6 at.% {sup 6}Li. In this paper, a new lithium isotope separation technique using an ionic-liquid impregnated organic membrane is proposed. In order to separate and concentrate lithium isotopes, only lithium ions are able to move through the membrane by electrodialysis between the cathode and the anode in lithium solutions. Preliminary experiments of lithium isotope separation were conducted using this phenomenon. Organic membranes impregnated with TMPA-TFSI and PP13-TFSI as ionic liquids were prepared, and the relationship between the {sup 6}Li separation coefficient and the applied electrodialytic conditions was evaluated using them. The results showed that the {sup 6}Li isotope separation coefficient in this method (about 1.1-1.4) was larger than that in the mercury amalgam method (about 1.06).

  9. Hyperfine structure in photoassociative spectra of 6Li2 and 7Li2

    NARCIS (Netherlands)

    Abraham, E.R.I.; McAlexander, W.I.; Stoof, H.T.C.; Hulet, R.G.

    1996-01-01

    We present spectra of hyperfine resolved vibrational levels of the A1Σu+and 1 3Σg+ states of 6Li2 and 7Li2 obtained via photoassociation of colliding ultracold atoms in a magneto-optical trap. A simple first-order perturbation theory analysis accurately accounts for the frequency splittings and rela

  10. Resonant, direct, and transfer breakup of 6Li by 112Sn

    Science.gov (United States)

    Chattopadhyay, D.; Santra, S.; Pal, A.; Kundu, A.; Ramachandran, K.; Tripathi, R.; Sarkar, D.; Sodaye, S.; Nayak, B. K.; Saxena, A.; Kailas, S.

    2016-12-01

    Projectile breakup cross sections in the 6Li+112Sn reaction have been measured at two beam energies, 30 and 22 MeV. Cross sections for sequential breakup of 6Li into α +d via its resonant state of 1+ (5.65 MeV) in the continuum have been measured for the first time along with two other dominant resonant states of 3+ (2.18 MeV) and 2+ (4.31 MeV) at Ebeam=30 MeV. However, at 22 MeV, the α +d breakup is found to be only due to direct breakup process. Cross sections measured for sequential breakup via two transfer channels, (6Li,5Li ) and (6Li,8Be ), into α +p and α +α , respectively, and the above α +d breakup channels compared with the results of coupled-channels calculations unravel the reaction mechanisms involving a weakly bound projectile and different processes leading to large inclusive α -particle production.

  11. Hard photodisintegration of 3He into a p d pair

    Science.gov (United States)

    Maheswari, Dhiraj; Sargsian, Misak M.

    2017-02-01

    The recent measurements of high energy photodisintegration of a 3He nucleus to a p d pair at 90∘ center of mass demonstrated an energy scaling consistent with the quark counting rule with an unprecedentedly large exponent of s-17. To understand the underlying mechanism of this process, we extended the theoretical formalism of the hard rescattering mechanism (HRM) to calculate the γ 3He→p d reaction. In HRM the incoming high energy photon strikes a quark from one of the nucleons in the target which subsequently undergoes hard rescattering with the quarks from the other nucleons, generating a hard two-body system in the final state of the reaction. Within the HRM we derived the parameter-free expression for the differential cross section of the reaction, which is expressed through the 3He→p d transition spectral function, the cross section of hard p d →p d scattering, and the effective charge of the quarks being interchanged during the hard rescattering process. The numerical estimates of all these factors resulted in the magnitude of the cross section, which is surprisingly in good agreement with the data.

  12. Comment on "Deep mixing of 3He: reconciling Big Bang and stellar nucleosynthesis".

    Science.gov (United States)

    Balser, Dana S; Rood, Robert T; Bania, T M

    2007-08-31

    Eggleton et al. (Reports, 8 December 2006, p. 1580) reported on a deep-mixing mechanism in low-mass stars caused by a Rayleigh-Taylor instability that destroys all of the helium isotope 3He produced during the star's lifetime. Observations of 3He in planetary nebulae, however, indicate that some stars produce prodigious amounts of 3He. This is inconsistent with the claim that all low-mass stars should destroy 3He.

  13. Nuclear reactions of the system {sup 6} Li on {sup 58} Ni near the Coulomb barrier; Reacciones nucleares del sistema {sup 6} Li sobre {sup 58} Ni cerca de la barrera de Coulomb

    Energy Technology Data Exchange (ETDEWEB)

    Lizcano, D.; Aguilera, E.F.; Garcia M, H.; Martinez Q, E. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    Protons, alpha particles and deuterons coming from the reactions {sup 6} Li + {sup 58} Ni are detected to three different energy around the Coulomb barrier. The possible effects of the weakly bound character of the projectile are studied and the results are compared with previous data for the system {sup 6} Li + {sup 59} Co. (Author)

  14. Gamow shell model description of radiative capture reactions $^6$Li$(p,\\gamma)$$^7$Be and $^6$Li$(n,\\gamma)$$^7$Li

    CERN Document Server

    Dong, G X; Fossez, K; Płoszajczak, M; Jaganathen, Y; Betan, R M Id

    2016-01-01

    According to standard stellar evolution, lithium abundance is believed to be a useful indicator of the stellar age. However, many evolved stars like red giants show huge fluctuations around expected theoretical abundances that are not yet fully understood. The better knowledge of nuclear reactions that contribute to the creation and destruction of lithium can help to solve this puzzle. In this work we apply the Gamow shell model (GSM) formulated in the coupled-channel representation (GSM-CC) to investigate the mirror radiative capture reactions $^6$Li$(p,\\gamma)$$^7$Be and $^6$Li$(n,\\gamma)$$^7$Li. The cross-sections are calculated using a translationally invariant Hamiltonian with the finite-range interaction which is adjusted to reproduce spectra, binding energies and one-nucleon separation energies in $^{6-7}$Li, $^7$Be. All relevant $E1$, $M1$, and $E2$ transitions from the initial continuum states to the final bound states $J={3/2}_1^-$ and $J={1/2}^-$ of $^7$Li and $^7$Be are included. We demonstrate th...

  15. K− 3He and K− 4He interactions at low energies

    Directory of Open Access Journals (Sweden)

    Grishina V.Yu.

    2010-04-01

    Full Text Available Using the multiple scattering approach (MSA in the fixed center approximation we calculated the K− 4He and K− 3He scattering lengths. The K− 4He scattering length is also analyzed in the optical potential model. Within the MSA the K− 3He final state interaction factor was also calculated. It is found that the K− 3He mass spectrum for the pd → 3HeK+ K− reaction is expected to be influenced by the K− 3He FSI effect.

  16. Ab initio study of {sup 2}H(d,{gamma}){sup 4}He, {sup 2}H(d,p){sup 3}H, and {sup 2}H(d,n){sup 4}He reactions and the tensor force

    Energy Technology Data Exchange (ETDEWEB)

    Arai, K.; Aoyama, S.; Suzuki, Y.; Descouvemont, P.; Baye, D. [Division of General Education, Nagaoka National College of Technology, 888 Nishikatakai, Nagaoka, Niigata, 940-8532 (Japan); Center for Academic Information Service, Niigata University, Niigata 950-2181 (Japan); Department of Physics, Niigata University, Niigata 950-2181, Japan and RIKEN Nishina Center, Wako 351-0198 (Japan); Physique Nucleaire Theorique et Physique Mathematique, C.P.229, Universite Libre de Bruxelles, B 1050 Brussels (Belgium); Physique Quantique, CP165/82, Universite Libre de Bruxelles, B-1050 Brussels (Belgium)

    2012-11-12

    The {sup 2}H(d,p){sup 3}H, {sup 2}H(d,n){sup 3}He, and {sup 2}H(d,{gamma}){sup 4}He reactions at low energies are studied with realistic nucleon-nucleon interactions in an ab initio approach. The obtained astrophysical S-factors are all in very good agreement with experiment. The most important channels for both transfer and radiative capture are all found to dominate thanks to the tensor force.

  17. Importance of $1n$-stripping process in the $^{6}$Li+$^{159}$Tb reaction

    CERN Document Server

    Pradhan, M K; Roy, Subinit; Basu, P; Goswami, A; Kshetri, R; Palit, R; Parkar, V V; Ray, M; Sarkar, M Saha; Santra, S

    2013-01-01

    The inclusive cross sections of the $\\alpha$-particles produced in the reaction $^{6}$Li+$^{159}$Tb have been measured at energies around the Coulomb barrier. The measured cross sections are found to be orders of magnitude larger than the calculated cross sections of $^{6}$Li breaking into $\\alpha$ and $d$ fragments, thus indicating contributions from other processes. The experimental cross sections of $1n$-stripping and $1n$-pickup processes have been determined from an entirely different measurement, reported earlier. Apart from incomplete fusion and/ $d$-transfer processes, the $1n$-stripping process is found to be a significant contributor to the inclusive $\\alpha$-particle cross sections in this reaction.

  18. Narrow-linewidth cooling of $^{6}$Li atoms using the 2S-3P transition

    CERN Document Server

    Chen, Hao-Ze; Wu, Yu-Ping; Liu, Xiang-Pei; Wang, Xiao-Qiong; Chen, Yu-Ao; Pan, Jian-Wei

    2016-01-01

    We report on a narrow-linewidth cooling of $^{6}$Li atoms using the $2S_{1/2}\\to 3P_{3/2}$ transition in the ultraviolet (UV) wavelength regime. By combining the traditional red magneto-optical trap (MOT) at 671 nm and the UV MOT at 323 nm, we obtain a cold sample of $1.3\\times10^9$ atoms with a temperature of 58 $\\mu$K. Furthermore, we demonstrate a high efficiency magnetic transport for $^{6}$Li atoms with the help of the UV MOT. Finally, we obtain $8.1\\times10^8$ atoms with a temperature of 296 $\\mu$K at a magnetic gradient of 198 G/cm in the science chamber with a good vacuum environment and large optical access.

  19. {sup 3}He retention in LaNi{sub 5} and Pd tritides: Dependence on stoichiometry, {sup 3}He distribution and aging effects

    Energy Technology Data Exchange (ETDEWEB)

    Thiebaut, S. [Commissariat a l' Energie Atomique, Centre d' Etudes de Valduc, 21120 Is/Tille (France)], E-mail: stephanie.thiebaut@cea.fr; Douilly, M.; Contreras, S.; Limacher, B. [Commissariat a l' Energie Atomique, Centre d' Etudes de Valduc, 21120 Is/Tille (France); Paul-Boncour, V.; Decamps, B.; Percheron-Guegan, A. [Laboratoire de Chimie Metallurgique des Terres Rares, CNRS, 2-8 rue H. Dunant, 94320 Thiais (France)

    2007-10-31

    This study compares the {sup 3}He retention properties at room temperature of both LaNi{sub 5} and Pd tritides after more than 18 and 13 years, respectively. The effects of stoichiometry have been investigated by following {sup 3}He retention in sub-stoichiometric and stoichiometric samples for both tritides, and in replenished samples for Pd tritide. For both compounds, the change of thermodynamic and structural properties due to {sup 3}He retention upon aging time has also been studied by PcT diagrams, X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) measurements. Transmission electron microscopy (TEM) observations were also performed for Pd only. Both LaNi{sub 5} and Pd tritides retain more than 95% of {sup 3}He for at least 9 years of aging. However, the influence of {sup 3}He in the matrix has completely different effects since LaNi{sub 5} tritide looses its thermodynamic and structural properties after 2.8 years of aging, whereas these properties are outstandingly well preserved in Pd tritide for at least 10 years. This difference has been attributed to a different distribution of {sup 3}He atoms, leading to different kind of defects produced by {sup 3}He retention in both materials.

  20. Formation of eta'(958) Meson Bound States by the 6Li(gamma,d) reaction

    CERN Document Server

    Miyatani, M; Nagahiro, H; Hirenzaki, S

    2016-01-01

    We have investigated the 6Li(gamma,d) reaction theoretically for the formation of the eta'(958) mesic nucleus close to the recoilless kinematics. We have developed the theoretical formula and reported the quantitative results of the formation spectra for various cases in this article. We have found that the formation cross sections are reduced by the effects of the fragile deuteron form factor.

  1. Autler-Townes splitting in two-color photoassociation of 6Li

    CERN Document Server

    Schloeder, U; Silber, C; Zimmermann, C; Schloeder, Ulrike; Deuschle, Thomas; Silber, Christian; Zimmermann, Claus

    2003-01-01

    We report on high-resolution two-color photoassociation spectroscopy in the triplet system of magneto-optically trapped 6Li. The absolute transition frequencies have been measured. Strong optical coupling of the bound molecular states has been observed as Autler-Townes splitting in the photoassociation signal. The spontaneous bound-bound transition rate is determined and the molecule formation rate is estimated. The observed lineshapes are in good agreement with the theoretical model.

  2. A possible in situ 3H and 3He source in Earth's interior: an alternative explanation of origin of 3He in deep Earth.

    Science.gov (United States)

    Jiang, Songsheng; Liu, Jing; He, Ming

    2010-07-01

    Origin of (3)He in the Earth is a mystery. Lacking a production mechanism, scientists assume (3)He was trapped in the Earth, when the Earth was formed. In contrast to this assumption, we have found (3)He and (3)H concentrations in excess of the atmospheric values in the deep waters of the volcanic Lakes Pavin (France), Laacher (Germany) and Nemrut (Turkey). This paper reports the result of finding (3)H in these three volcanic lakes that appear to originate from the mantle. Because (3)H has a half-life of 12.3 years, this (3)H and the resulting (3)He must have formed recently in the mantle and not be part of a primordial reservoir. The nuclear reactions that generate tritium might be a source of "missing" energy in the interior of the Earth.

  3. Quasi-Bound 3He − η State and Spin-Observables of the Reaction pd → 3Heη

    Directory of Open Access Journals (Sweden)

    Uzikov Yu.N.

    2010-04-01

    Full Text Available A formalism for total set of spin observables of the reaction pd → 3Heη derived in a model independent way is presented and a possibility to perform a complete polarization experiment is investigated. Separation of s- and p-wave amplitudes of this reaction in the threshold region allows one to determine a position of the quasibound pole in the 3He − η system. It is shown that in order to get such a separation one should measure spin-transfer coefficients in addition to analyzing powers and spin-correlations. Specific observables, given by products of one s- and one p-wave amplitudes, are found. Measurement of these observables will provide new independent information on the 3He − η pole position and this allows one to determine whether the 3He − η state is quasi-bound or anti-bound.

  4. Near threshold two meson production with the pd→3Heπ+π- and pd→3HeK+K- reactions

    Science.gov (United States)

    Bellemann, F.; Berg, A.; Bisplinghoff, J.; Bohlscheid, G.; Ernst, J.; Henrich, C.; Hinterberger, F.; Ibald, R.; Jahn, R.; Jarczyk, L.; Joosten, R.; Kozela, A.; Machner, H.; Magiera, A.; Maschuw, R.; Mayer-Kuckuk, T.; Mertler, G.; Munkel, J.; von Neumann-Cosel, P.; Rosendaal, D.; von Rossen, P.; Schnitker, H.; Scho, K.; Smyrski, J.; Strzalkowski, A.; Tölle, R.; Wilkin, C.

    2000-06-01

    Near threshold two meson production via the reactions pd→3Heπ+π- and pd→3HeK+K- was measured kinematically complete with the MOMO experiment at COSY. The obtained two pion invariant mass spectra and angular distributions depict a remarkable deviation from phase space. The two kaon data are consistent with phase space topped by a clear signal of the φ meson.

  5. A 3He Cryostat for Scientific Measurements in Pulsed High Magnetic Fields

    Science.gov (United States)

    Wang, Shaoliang; Li, Liang; Liu, Mengyu; Zuo, Huakun; Peng, Tao

    A top loading 3He cryostat has been developed for scientific experiments with a 60 T pulsed magnetic field facility at Wuhan National High Magnetic Field Center. The cryostat consists of a 4He bath cryostat, a 3He insert and a closed circulation system for 3He gas handling. To eliminate the eddy current heating during the pulse, the tail of the 3He insert with a vacuum space at the bottom is made from fiberglass tubing coated with epoxy. The 3He bath is separated from the 4He bath with the vacuum space. The 4He bath cryostat provides cooling power to condense 3He gas by a neck tube on top of the tail. Experimental results have shown that the sample can be cooled down to 385 mK and kept cold for more than 150 second by one-shot cooling, which is sufficiently long for an experiment in a pulsed high magnetic field.

  6. Development of polarized {sup 3}He filter for polarized neutron experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, K.; Sato, H.; Yoshimi, A.; Asahi, K. [Tokyo Inst. of Tech. (Japan). Faculty of Science; Masuda, Y.; Muto, S.; Ishimoto, S.; Morimoto, K.

    1996-08-01

    A high-pressure polarized {sup 3}He gas cell, pumped with two diode lasers, has been developed at KEK for use as a polarizer and a spin analyzer for low energy neutrons. The polarization attained of {sup 3}He was determined through the measurement of the transmission of the unpolarized neutrons through the {sup 3}He cell. So far we obtained P{sub He}=18% at 10 atm and P{sub He}=12% at 20 atm. (author)

  7. Polarized [sup 3]He ion source based on polarized electron capture

    Energy Technology Data Exchange (ETDEWEB)

    Ohshima, Takashi (Osaka Univ., Toyonaka (Japan). Faculty of Science)

    1993-11-01

    The [sup 3]He[sup +] ions which are formed by [sup 3]He[sup 2+] ions capturing the polarized electrons of the sodium atoms polarized by optical pumping become nuclear polarized beam, as electron polarization shifts to nuclei by ultrafine interaction. When the current of [sup 3]He[sup 2+] ions was 2 e[mu]A, and the degree of polarization of sodium atoms was 0.30[+-]0.05, the [sup 3]He[sup +] beam of nuclear polarization degree 0.0415[+-]0.0061 and beam current 40 nA was obtained. By carrying out the improvement such as the increase of the degree of polarization of sodium or the current of [sup 3]He[sup 2+], it can be expected to form the polarized beam of current more than 10 [mu]A and degree of polarization close to 30%. The polarization experiment carried out so far was mostly on protons and deuterons, and as for [sup 3]He, there was only one polarization experiment. In Research Center for Nuclear Physics, Osaka University, the [sup 3]He beam up to 530 MeV can be obtained by using the ring cyclotron, therefore, it was decided to develop the polarized [sup 3]He ion source using polarized electron capture. The principle of polarization formation, the experimental equipment consisting of ECR ion source, polarized Na target and [sup 3]He nuclear polarization measuring part, and the experimental results are reported. (K.I.).

  8. {sup 3}He-MRI in follow-up of lung transplant recipients

    Energy Technology Data Exchange (ETDEWEB)

    Gast, Klaus Kurt; Zaporozhan, Julia; Ley, Sebastian; Biedermann, Alexander; Knitz, Frank; Eberle, Balthasar; Schmiedeskamp, Joerg; Heussel, Claus-Peter; Mayer, Eckhard; Schreiber, Wolfgang Guenter; Thelen, Manfred; Kauczor, Hans-Ulrich [Department of Radiology, Johannes Gutenberg University Hospital, Langenbeckstrasse 1, 55131, Mainz (Germany)

    2004-01-01

    The aim of this study was to evaluate the possible contribution of {sup 3}He-MRI to detect obliterative bronchiolitis (OB) in the follow-up of lung transplant recipients. Nine single- and double-lung transplanted patients were studied by an initial and a follow-up {sup 3}He-MRI study. Images were evaluated subjectively by estimation of ventilation defect area and quantitatively by individually adapted threshold segmentation and subsequent calculation of ventilated lung volume. Bronchiolitis obliterans syndrome (BOS) was diagnosed using pulmonary function tests. At {sup 3}He-MRI, OB was suspected if ventilated lung volume had decreased by 10% or more at the follow-up MRI study compared with the initial study. General accordance between pulmonary function testing and {sup 3}He-MRI was good, although subjective evaluation of {sup 3}He-MRI underestimated improvement in ventilation as obtained by pulmonary function tests. The {sup 3}He-MRI indicated OB in 6 cases. According to pulmonary function tests, BOS was diagnosed in 5 cases. All diagnoses of BOS were also detected by {sup 3}He-MRI. In 2 of these 5 cases, {sup 3}He-MRI indicated OB earlier than pulmonary function tests. The results support the hypothesis that {sup 3}He-MRI may be sensitive for early detection of OB and emphasize the need for larger prospective follow-up studies. (orig.)

  9. The Detection of 3He+ in a Planetary Nebula Using the VLA

    CERN Document Server

    Balser, D S; Bania, T M; Rood, R T; Balser, Dana S.; Rood, Robert T.

    2006-01-01

    We used the VLA to search for 3He+ emission from two Galactic planetary nebulae (PNe): NGC6572 and J320}. Standard stellar models predict that the 3He/H abundance ratios for PNe should be 1-2 orders of magnitude higher than the primordial value (3He/H ~ 1e-5 by number) determined from Galactic HII region abundances and confirmed by WMAP cosmic microwave background results. Chemical evolution models suggest that fewer than 5% of all PNe enrich the interstellar medium (ISM) with 3He at the level of standard stellar models. Our target PNe are therefore anomalous in that they were selected from a sample deliberately biased to contain objects with properties that maximized the likelihood of a 3He detection by the VLA. We have detected the 8.665 GHz hyperfine 3He+ transition in J320 at the 4 sigma level. The 3He/H abundance ratio is 1.9e-3 with roughly a factor of two uncertainty. For NGC 6572 we find an upper limit of 3He/H <= 1e-3. This detection of 3He in J320 makes it the second PN known to have an anomalous...

  10. Development of a thermodynamic model for a cold cycle 3He-4He dilution refrigerator

    Science.gov (United States)

    Mueller, B. W.; Miller, F. K.

    2016-10-01

    A thermodynamic model of a 3He-4He cold cycle dilution refrigerator with no actively-driven mechanical components is developed and investigated. The refrigerator employs a reversible superfluid magnetic pump, passive check valves, a phase separation chamber, and a series of recuperative heat exchangers to continuously circulate 3He-4He and maintain a 3He concentration gradient across the mixing chamber. The model predicts cooling power and mixing chamber temperature for a range of design and operating parameters, allowing an evaluation of feasibility for potential 3He-4He cold cycle dilution refrigerator prototype designs. Model simulations for a prototype refrigerator design are presented.

  11. Optimization of {sup 6}LiF:ZnS(Ag) Scintillator Light Yield Using Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Yehuda-Zada, Y. [Nuclear Research Center Negev, Beer-Sheva (Israel); Ben-Gurion University (Israel); Pritchard, K.; Ziegler, J.B.; Cooksey, C.; Siebein, K. [National Institute of Standards and Technology, Gaithersburg, Maryland (United States); Jackson, M.; Hurlbut, C. [Eljen Technology, Sweetwater Texas (United States); Kadmon, Y.; Cohen, Y.; Maliszewskyj, N.C. [Nuclear Research Center Negev, Beer-Sheva (Israel); Ibberson, R.M.; Majkrzak, C.F. [National Institute of Standards and Technology, Gaithersburg, Maryland (United States); Orion, Y. [Ben-Gurion University (Israel); Osovizky, A. [National Institute of Standards and Technology, Gaithersburg, Maryland (United States); Rotem Industries Ltd, Rotem Industrial Park (Israel); University of Maryland (United States)

    2015-07-01

    Neutrons provide an effective tool to probe materials structure. Neutron diffraction is a method to determine the atomic and magnetic structure of a material based on neutron scattering. By this method a collimated incident beam of thermal neutrons heat the examined sample and based on the obtained diffraction pattern information on the structure of the material is provided. Research for developing a novel cold neutron detector for Chromatic Analysis Neutron Diffractometer Or Reflectometer (CANDOR) is underway at the NIST center for neutron research. The system unique design is aimed to provide over ten times fold faster analysis of materials than conventional system. In order to achieve the fast analysis a large number of neutron detectors is required. A key design constraint for this detector is the thickness of the neutron sensitive element. This is met using {sup 6}LiF:ZnS(Ag) scintillation material with embedded wavelength shifting (WLS) fibers conducting scintillation light to silicon photomultiplier photo-sensors. The detector sensitivity is determined by both the neutron capture probability ({sup 6}Li density) and the detectable light output produced by the ZnS(Ag) ionization, the latter of which is hindered by the fluorescence absorption of the scintillation light by the ZnS. Tradeoffs between the neutron capture probability, stimulated light production and light attenuation for determining the optimal stoichiometry of the {sup 6}LiF and ZnS(Ag) as well as the volume ratio of scintillator and fiber. Simulations performed using the GEANT4 Monte Carlo package were made in order to optimize the detector design. GEANT4 enables the investigation of the neutron interaction with the detector, the ionization process and the light transfer process following the nuclear process. The series of conversions required for this detector were modelled: - A cold neutron enters the sensor and is captured by {sup 6}Li in the scintillator mixture ({sup 6}Li (n,α) {sup 3}H

  12. Astrophysical S factor for the radiative-capture reaction p{sup 6}Li {yields} {sup 7}Be{gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Dubovichenko, S. B., E-mail: sergey@dubovichenko.ru [National Space Agency of the Republic of Kazakhstan, Fessenkov Astrophysical Institute, National Center of Space Research and Technology (Kazakhstan); Burtebaev, N., E-mail: burteb@inp.kz; Zazulin, D. M.; Kerimkulov, Zh. K. [National Nuclear Center of Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Amar, A. S. A. [Al-Farabi Kazakh National University (Kazakhstan)

    2011-07-15

    A new measurement of differential cross sections for elastic p{sup 6}Li scattering in the energy range 0.35-1.2 MeV was performed. A partial-wave analysis of the data obtained in this way was carried out, and potentials simulating the p{sup 6}Li interaction were constructed. Various experiments devoted to studying elastic p{sup 6}Li scattering over the broad energy range of 0.5-50 MeV were analyzed on the basis of the optical model. By using the potentials obtained from the partial-wave analysis, the possibility of describing the astrophysical S factor for radiative proton capture on {sup 6}Li at low energies was considered within the potential cluster model involving forbidden states.

  13. Standard model contribution to the electric dipole moment of the deuteron, 3H, and 3He nuclei

    Science.gov (United States)

    Yamanaka, Nodoka; Hiyama, Emiko

    2016-02-01

    We calculate for the first time the electric dipole moment (EDM) of the deuteron, 3H, and 3He nuclei generated by the one-meson exchange CP-odd nuclear force in the standard model. The effective |Δ S| = 1 four-quark operators are matched to the |Δ S| = 1 standard model processes involving the CP phase of the Cabibbo-Kobayashi-Maskawa matrix at the electroweak scale and run down to the hadronic scale μ = 1 GeV according to the renormalization group evolution in the next-to-leading logarithmic order. At the hadronic scale, the hadron matrix elements are modeled in the factorization approach. We then obtain the one-meson (pion, eta meson, and kaon) exchange CP-odd nuclear force, which is the combination of the |Δ S| = 1 meson-baryon vertices which issue from the penguin operator and the hyperon-nucleon transition. From this CP-odd nuclear force, the nuclear EDM is calculated with the realistic Argonne v18 interaction and the CP-odd nuclear force using the Gaussian expansion method. It is found that the EDMs of light nuclear systems are of order O (10-31) e cm. We also estimate the standard model contribution to other hadronic CP violating observables such as the EDMs of 6Li, 9Be nuclei, and the atomic EDMs of 129Xe, 199Hg, 211Rn, and 225Ra generated through the nuclear Schiff moment. We then analyze the source of theoretical uncertainties and show some possible ways to overcome them.

  14. Model Calculation of n + 6Li Reactions Below 20 MeV

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-Shang; HAN Yin-Lu

    2001-01-01

    Based on the unified Hauser-Feshbach and exciton model for light nuclei, the calculations of reaction cross sections and the double-differential cross sections for n + 6Li are performed. Since all of the first-particle emissions are from the compound nucleus to the discrete levels, the angular momentum coupling effect in pre-equilibrium mechanism must be taken into account. The fitting of the measured data indicates that the three-body break-up process needs to be involved, and the pre-equilibrium reaction mechanism dominates the reaction processes. In light nucleus reactions the recoil effect must be taken into account.``

  15. Comparative analysis of pulse shape discrimination methods in a {sup 6}Li loaded plastic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Balmer, Matthew J.I., E-mail: m.balmer@lancaster.ac.uk [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Gamage, Kelum A.A. [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Taylor, Graeme C. [Neutron Metrology Group, National Physical Laboratory, Teddington, TW11 0LW (United Kingdom)

    2015-07-11

    Three algorithms for discriminating between fast neutrons, thermal neutrons and gamma rays in a {sup 6}Li loaded plastic scintillator have been compared. Following a literature review of existing pulse shape discrimination techniques, the performance of the charge comparison method, triangular filtering and frequency gradient analysis were investigated in this work. The scintillator was exposed to three different mixed gamma/neutron radiation fields. The figure of merit of neutron/gamma separation was investigated over a broad energy range, as well as for the neutron capture energy region. After optimisation, all three methods were found to perform similarly in terms of neutron/gamma separation.

  16. {sup 6}Li breakup and suppression of complete fusion above the Coulomb barrier

    Energy Technology Data Exchange (ETDEWEB)

    Elmahdy, N.A. [Modern Academy for Engineering and Technology, Cairo (Egypt); Denikin, A.S. [Dubna International University, Dubna (Russian Federation); JINR, Flerov Laboratory of Nuclear Reactions, Dubna (Russian Federation); Ismail, M.; Ellithi, A.Y. [Cairo University, Cairo (Egypt)

    2015-05-15

    We study the role of the projectile breakup in the fusion process by example of the {sup 6}Li reactions with the {sup 59}Co, {sup 144}Sm and {sup 209}Bi targets in vicinity of the Coulomb barrier. The coupled channel and distorted wave approaches are employed in order to calculate the complete fusion and the breakup cross sections, respectively. The partial cross sections in both the channels are compared in order to estimate the breakup fraction responsible for the suppression of complete fusion. The calculations are compared with available experimental data. The conclusions and recommendations are made. (orig.)

  17. DC discharge characteristics and fluorine atom yield in NF3/He

    Institute of Scientific and Technical Information of China (English)

    Liping Duo; Shukai Tang; Haijun Yu; Jian Wang; Xiangde Min; Liucheng Li; Yuqi Jin; Bailing Yang; Fengting Sang

    2006-01-01

    @@ DC discharge characteristics of NF3/He have been investigated experimentally under different experimental conditions, for example, different electrode materials, separations, flow rates of the gas NF3 or He, and series resistances. The optimum discharge parameters and the fluorine atom yield from the DC discharge of NF3/He as function of load power are studied experimentally.

  18. Measurement of fast minority /sub 3/He/sup + +/ energy distribution during ICRF heating

    Science.gov (United States)

    Post, D.E. Jr.; Grisham, L.R.; Medley, S.S.

    A method and means for measuring the fast /sub 3/He/sup + +/ distribution during /sub 3/He/sup + +/ minority Ion Cyclotron Resonance Frequency (ICRF) heating is disclosed. The present invention involves the use of 10 to 100 keV beams of neutral helium atoms to neutralize the fast /sub 3/He/sup + +/ ions in a heated plasma by double charge exchange (/sub 3/He/sup + +/ + /sub 4/He/sup 0/ ..-->.. /sub 3/He/sup 0/ + /sub 4/He/sup + +/). The neutralized fast /sub 3/He/sup 0/ atoms then escape from the hot plasma confined by a magnetic field and are detected by conventional neutral particle analyzing means. This technique permits the effectiveness of the coupling of the ion cyclotron waves to the /sub 3/He/sup + +/ minority ions to be accurately measured. The present invention is particularly adapted for use in evaluating the effectiveness of the intermediate coupling between the RF heating and the /sub 3/He/sup + +/ in an energetic toroidal plasma.

  19. Detection of D-^3He Fusion γ-Rays using Gas Cherenkov Detectors

    Science.gov (United States)

    Kim, Y.; Herrmann, H. W.; Mack, J. M.; Young, C. S.; Hale, G. M.; Evans, S. C.; Sedillo, T. J.; Cahill, A.; Horsfield, C. J.; Rubery, M. S.; Grafil, E.; Stoeffl, W.; Waugh, C.; Rinderknecht, H. G.; Frenje, J. A.; Petrasso, R. D.; Miller, E. Kirk

    2012-10-01

    The high-energy γ-ray from ^3He(d,γ)^5Li reactions has drawn the attention of the nuclear physics and fusion community as a diagnostic signature to study the ^5Li nuclear structure and the D-^3He fusion reaction. In the past, the D-^3He γ-rays have been measured via accelerator-based beam-target experiments and recently in tokamak-based fusion reactors. In this work, we report the detection of D-^3He fusion γ-rays generated from inertial confinement fusion (ICF) implosions at the OMEGA laser facility. The γ-ray signal observed using Gas Cherenkov Detectors (GCD) is proportional to the independently measured 14.7-MeV fusion proton yield and provides a high-bandwidth alternative to fusion protons for D-^3He burn-history measurements. By comparing γ-rays from D-^3He and D-T implosions, we were able to examine (1) similarities in the γ-ray spectra of D-^3He and D-T and (2) disparities in the γ-to-particle branching ratios of D-^3He and D-T. This experimental work motivates further theoretical investigation of the multichannel ^5Li- and ^5He-system.

  20. ABC Effect and Resonance Structure in the Double-Pionic Fusion to 3He

    Directory of Open Access Journals (Sweden)

    Pricking A.

    2012-12-01

    Full Text Available Historically the double-pionic fusion to 3He is the reaction, where the ABC effect (low-mass enhancement of the ππ-invariant mass spectrum was observed for the first time more than 50 years ago. Meanwhile exclusive and kinematically complete high-statistics measurements with WASA at COSY revealed a strict correlation between the ABC effect and a narrow resonance structure with I(JP = 0(3+ in the total cross section of the most basic double-pionic fusion, the pn → dπ0π0 reaction. In order to investigate the situation in the double-pionic fusion to 3He the energy dependence of the ABC effect in the fusion to 3He has been measured by fixed energy measurements of the type pd →3Heππ as well as by quasifree and coherent measurements of the type dd →3He n ππ.

  1. Scintillation properties of semiconducting {sup 6}LiInSe{sub 2} crystals to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, Brenden [Y-12 National Security Complex, Oak Ridge, TN (United States); Vanderbilt University, Nashville, TN (United States); Groza, Michael; Tupitsyn, Eugene [Fisk University, Nashville, TN (United States); Lukosi, Eric [University of Tennessee, Knoxville, TN (United States); Stassun, Keivan; Burger, Arnold [Vanderbilt University, Nashville, TN (United States); Fisk University, Nashville, TN (United States); Stowe, Ashley [Y-12 National Security Complex, Oak Ridge, TN (United States); Vanderbilt University, Nashville, TN (United States); University of Tennessee, Knoxville, TN (United States)

    2015-11-21

    {sup 6}LiInSe{sub 2} has gained attention recently as a semiconducting thermal neutron detector. As presented herein, the chalcogenide compound semiconductor also detects incident neutrons via scintillation, making {sup 6}LiInSe{sub 2} the only lithium containing semiconductor to respond to neutrons via both detection mechanisms. Both yellow and red crystals, which appear in the literature, were investigated. Only the yellow crystal responded favorably to ionizing radiation, similar to the semiconducting operation utilizing electrodes. The obtained light yield for yellow crystals is 4400 photons/MeV, referenced to Bi{sub 4}Ge{sub 3}O{sub 12} (BGO).The estimated thermal neutron light yield was 21,000 photons/thermal neutron. The two measured decay time components were found to be 31±1 ns (49%) and 143±9 ns (51%).This crystal provides efficient, robust detection of neutrons via scintillation with respectable light yield and rapid response, enabling its use for a broad array of neutron detection applications.

  2. On the nuclear $(n;t)-$reaction in the three-electron ${}^{6}$Li atom

    CERN Document Server

    Frolov, Alexei M

    2012-01-01

    The nuclear $(n;t)-$reaction of the three-electron ${}^{6}$Li atom with thermal/slow neutrons is considered. An effective method has been developed for determining the probabilities of formation of various atoms and ions in different bound states. We discuss a number of fundamental questions directly related to numerical computations of the final state atomic probabilities. A few appropriate variational expansions for atomic wave functions of the incident lithium atom and final helium atom and/or tritium negatively charged ion are discussed. It appears that the final ${}^4$He atom arising during the nuclear $(n,{}^{6}$Li; ${}^4$He$,t)$-reaction in the three-electron Li atom can also be created in its triplet states. The formation of the quasi-stable three-electron $e^{-}_3$ during the nuclear $(n; t)-$reaction at the Li atom is briefly discussed. Bremsstrahlung emitted by atomic electrons accelerated by the rapidly moving fragments from this reaction is analyzed. The frequency spectrum of the emitted radiatio...

  3. Line shift, line asymmetry, and the 6Li/7Li isotopic ratio determination

    CERN Document Server

    Cayrel, Roger; Chand, Hum; Bonifacio, Piercarlo; Spite, Monique; Spite, François; Petitjean, Patrick; Ludwig, Hans-Günter; Caffau, Elisabetta

    2007-01-01

    Context: Line asymmetries are generated by convective Doppler shifts in stellar atmospheres, especially in metal-poor stars, where convective motions penetrate to higher atmospheric levels. Such asymmetries are usually neglected in abundance analyses. The determination of the 6Li/7Li isotopic ratio is prone to suffering from such asymmetries, as the contribution of 6Li is a slight blending reinforcement of the red wing of each component of the corresponding 7Li line, with respect to its blue wing. Aims: The present paper studies the halo star HD 74000 and estimates the impact of convection-related asymmetries on the Li isotopic ratio determination. Method: Two methods are used to meet this aim. The first, which is purely empirical, consists in deriving a template profile from another element that can be assumed to originate in the same stellar atmospheric layers as Li I, producing absorption lines of approximately the same equivalent width as individual components of the 7Li I resonance line. The second metho...

  4. {sup 3}He retention and structural evolution in erbium tritides: Phase and aging effects

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, X.S., E-mail: zlxs77@163.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Thin Film Centre, Scottish Universities Physics Alliance (SUPA), University of West of Scotland, Paisley PA1 2BE, Scotland (United Kingdom); Zhang, L.; Wang, W.D.; Liu, Q. [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Peng, S.M., E-mail: pengshuming@caep.cn [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Ding, W.; Long, X.G.; Cheng, G.J.; Liang, J.H. [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Fu, Y.Q. [Thin Film Centre, Scottish Universities Physics Alliance (SUPA), University of West of Scotland, Paisley PA1 2BE, Scotland (United Kingdom)

    2015-06-15

    Highlights: • Effects of phase changes on {sup 3}He retention of Er tritide films were investigated. • The α phase in Er tritide films had no apparent effect on {sup 3}He release/retention. • Tritium content in the β phase showed significant effects on {sup 3}He retention. • Evolution of {sup 3}He in the β phase was apparently influenced by the γ phase. • Effects of phase changes on structure evolution of Er tritides were investigated. - Abstract: Effects of phase changes on {sup 3}He release/retention and crystal lattice evolution during aging of erbium (Er) tritide films were investigated using X-ray diffraction. The contents of α phase and γ phase in the Er tritide films showed significant different effects on {sup 3}He release/retention. The initial tritium stoichiometry or excess tritium atoms accommodated in the octahedral sites and the microstructure (i.e., the texture and Er{sub 2}O{sub 3} oxide inclusions) played an important role for the {sup 3}He release and the evolution of {sup 3}He bubbles in the β phase Er tritide films. In the β + γ region, evolution of {sup 3}He in the β phase was apparently influenced by the γ phase, which could result in a strongly anisotropic lattice dilation and an earlier inflection point of the expansion rate of (1 1 1) lattice parameter. A preferred occupation of {sup 3}He in basal plane of the hexagonal γ phase and the lattice expansion along the hexagonal direction were identified.

  5. PREFACE: JCNS Workshop on Modern Trends in Production and Applications of Polarized 3He

    Science.gov (United States)

    Ioffe, Alexander; Babcock, Earl; Gutberlet, Thomas

    2011-03-01

    Polarized neutron scattering techniques are an indispensable and highly requested tool for studying magnetic phenomena in condensed matter. The different coherent and incoherent scattering of isotopes such as protons and deuterons also allows applications of polarized neutrons in soft matter and biological studies of molecular and macromolecular dynamics. One method to polarize neutrons is to use polarized 3He gas which absorbs, or filters, one spin state of the neutron beam as it passes through it. Only about ten years ago, early polarized neutron scattering experiments using such 3He neutron spin filters (3He NSF) were being conducted using starting 3He polarizations of 55%. Currently there are two different commonly used methods to polarize high quantities of 3He. These methods both collisionally transfer spin polarization to ground state 3He nucleuses; one method uses optical pumping of an excited metastable state of 3He atoms, and the other uses optical pumping of the ground state of an alkali-metal vapour. Within the last decade immense progress in both methods has resulted in 3He polarizations of up to 80% being reported in atmosphere-pressure 3He cells by the world's leading labs. This progress in optical pumped 3He promises to give rise to much more efficient and novel polarized neutron scattering experiments as and also impacts other areas of science. Polarized 3He is additionally applied in research fields such as particle physics, fundamental studies and medicine. Thus not only the techniques and methods of polarization, but the research groups themselves exploring polarized 3He, have a large breadth and diversity spanning different fields of science and locations in the world. Given this diversity, it is rare for this community to meet as a group at any one meeting or conference. Because it is crucial to discuss new developments in 3He polarization in a multi-disciplinary international setting, an international workshop on "Modern Trends in Production

  6. Recent advances in polarized 3 He based neutron spin filter development

    Science.gov (United States)

    Chen, Wangchun; Gentile, Thomas; Erwin, Ross; Watson, Shannon; Krycka, Kathryn; Ye, Qiang; NCNR NIST Team; University of Maryland Team

    2015-04-01

    Polarized 3 He neutron spin filters (NSFs) are based on the strong spin-dependence of the neutron absorption cross section by 3 He. NSFs can polarize large area, widely divergent, and broadband neutron beams effectively and allow for combining a neutron polarizer and a spin flipper into a single polarizing device. The last capability utilizes 3 He spin inversion based on the adiabatic fast passage (AFP) nuclear magnetic resonance technique. Polarized 3 He NSFs are significantly expanding the polarized neutron measurement capabilities at the NIST Center for Neutron Research (NCNR). Here we present an overview of 3 He NSF applications to small-angle neutron scattering, thermal triple axis spectrometry, and wide-angle polarization analysis. We discuss a recent upgrade of our spin-exchange optical pumping (SEOP) systems that utilize chirped volume holographic gratings for spectral narrowing. The new capability allows us to polarize rubidium/potassium hybrid SEOP cells over a liter in volume within a day, with 3 He polarizations up to 88%, Finally we discuss how we can achieve nearly lossless 3 He polarization inversion with AFP.

  7. Recent advances in polarised {sup 3}He spin filters at the ILL

    Energy Technology Data Exchange (ETDEWEB)

    Petoukhov, A.K. [Institut Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France)]. E-mail: petukhov@ill.fr; Andersen, K.H. [Institut Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Jullien, D. [Institut Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Babcock, E. [Institut Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Chastagnier, J. [Institut Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Chung, R. [Institut Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Humblot, H. [Institut Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Lelievre-Berna, E. [Institut Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Tasset, F. [Institut Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Radu, F. [Institut fuer Experimentalphysik/Festkoerperphysik, Ruhr-Universitaet Bochum, 44780 Bochum (Germany); Wolff, M. [Institut fuer Experimentalphysik/Festkoerperphysik, Ruhr-Universitaet Bochum, 44780 Bochum (Germany); Zabel, H. [Institut fuer Experimentalphysik/Festkoerperphysik, Ruhr-Universitaet Bochum, 44780 Bochum (Germany)

    2006-11-15

    We report the present status and recent advances made in polarised-{sup 3}He spin-filters at the ILL. The Tyrex filling station is working reliably and producing polarised {sup 3}He for neutron spin filters on a daily basis. The latest spin-filter cells have wall relaxation times between 200 and 400 h - the longest relaxation times yet achieved for valve-sealed cells. Recent results using {sup 3}He spin filters for reflectometry are presented and compared to the presently used supermirror-based polarisation analysers. By increasing the optical thickness of {sup 3}He gas, we move into a regime in which the neutron beam polarisation decays with a time constant of the order of a thousand hours and is thus negligible within the 24 h time scale of an experiment. We present the performance of a {sup 3}He spin flipper, which inverts the polarisation direction of the {sup 3}He nuclei by adiabatic fast passage with a polarisation loss of 10{sup -5} per flip. The development of in situ filling of the spin-filter cell via a capillary is described. This 'local filling' technique enables {sup 3}He spin filters to be used in inaccessible regions, such as inside large-detector vacuum tanks and in high-radiation environments.

  8. AFP flipper devices: Polarized {sup 3}He spin flipper and shorter wavelength neutron flipper

    Energy Technology Data Exchange (ETDEWEB)

    Babcock, E. [Institut Laue Langevin (ILL), 38042 Grenoble (France)]. E-mail: babcock@ill.fr; Petoukhov, A. [Institut Laue Langevin (ILL), 38042 Grenoble (France); Chastagnier, J. [Institut Laue Langevin (ILL), 38042 Grenoble (France); Jullien, D. [Institut Laue Langevin (ILL), 38042 Grenoble (France); Lelievre-Berna, E. [Institut Laue Langevin (ILL), 38042 Grenoble (France); Andersen, K.H. [Institut Laue Langevin (ILL), 38042 Grenoble (France); Georgii, R. [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM-II), 85747 Garching (Germany); Masalovich, S. [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM-II), 85747 Garching (Germany); Boag, S. [ISIS, Rutherford Appelton Labs, Didcot OX11 0X (United Kingdom); Frost, C.D. [ISIS, Rutherford Appelton Labs, Didcot OX11 0X (United Kingdom); Parnell, S.R. [ISIS, Rutherford Appelton Labs, Didcot OX11 0X (United Kingdom)

    2007-07-15

    We describe the development of a polarized neutron device that combines a {sup 3}He neutron spin filter and a neutron spin flipper using adiabatic fast passage (AFP), to adiabatically reverse the {sup 3}He polarization and thus the neutron polarization with near perfect symmetry. A typical AFP sequence takes place in 2.5-7.5 ms, with the time for the {sup 3}He transition from P to -P much less, thus the neutron polarization is nearly perfectly reversed very quickly with only a 2x10{sup -5} loss in {sup 3}He polarization per flip. We believe this device, the {sup 3}He 'flipperizer' can become a standard option wherever a {sup 3}He spin filter is already in use. Our first on beam test was performed on MIRA at the new FRM-2 reactor in Garching using polarized {sup 3}He from HELIOS. We also briefly describe tests of a new neutron flipper based on AFP. This broad band neutron RF flipper was shown to create neutron flipping efficiencies of >99% at a neutron wavelength of 0.4 A. Neutron tests were performed on D3 (ILL) and on ROTAX (ISIS)

  9. First Detection of $^3$He$^+$ in the Planetary Nebula IC$\\,$418

    CERN Document Server

    Guzman-Ramirez, L; Zijlstra, A A; García-Miró, C; Morisset, C; Gray, M D

    2016-01-01

    The $^3$He isotope is important to many fields of astrophysics, including stellar evolution, chemical evolution, and cosmology. The isotope is produced in low-mass stars which evolve through the planetary nebula (PN) phase. $^3$He abundances in PNe can help test models of the chemical evolution of the Galaxy. We present the detection of the $^3$He$^+$ emission line using the single dish Deep Space Station 63, towards the PN IC$\\,$418. We derived a $^3$He/H abundance in the range 1.74$\\pm$0.8$\\times$10$^{-3}$ to 5.8$\\pm$1.7$\\times$10$^{-3}$, depending on whether part of the line arises in an outer ionized halo. The lower value for $^3$He/H ratio approaches values predicted by stellar models which include thermohaline mixing, but requires that large amounts of $^3$He are produced inside low-mass stars which enrich the interstellar medium (ISM). However, this over-predicts the $^3$He abundance in HII regions, the ISM, and proto-solar grains, which is known to be of the order of 10$^{-5}$. This discrepancy questi...

  10. Spin polarization of xenon films at low-temperature induced by {sup 3}He

    Energy Technology Data Exchange (ETDEWEB)

    Biskup, N.; Kalechofsky, N.; Candela, D

    2003-05-01

    We have measured the {sup 129}Xe spin-lattice relaxation time T{sub 1} for xenon films adsorbed on silica gel in an 8 T magnetic field at dilution refrigerator temperatures, both with and without {sup 3}He filling the sample cell. Without {sup 3}He, T{sub 1} increases rapidly as the temperature is lowered. With {sup 3}He, T{sub 1} is considerably shortened, and is consistent with temperature-independent quantum relaxation. Using this technique, it is possible to brute-force polarize large quantities of xenon in high B/T conditions.

  11. Triple oxygen isotopic composition of the high-3He/4He mantle

    Science.gov (United States)

    Starkey, N. A.; Jackson, C. R. M.; Greenwood, R. C.; Parman, S.; Franchi, I. A.; Jackson, M.; Fitton, J. G.; Stuart, F. M.; Kurz, M.; Larsen, L. M.

    2016-03-01

    Measurements of Xe isotope ratios in ocean island basalts (OIB) suggest that Earth's mantle accreted heterogeneously, and that compositional remnants of accretion are sampled by modern, high-3He/4He OIB associated with the Icelandic and Samoan plumes. If so, the high-3He/4He source may also have a distinct oxygen isotopic composition from the rest of the mantle. Here, we test if the major elements of the high-3He/4He source preserve any evidence of heterogeneous accretion using measurements of three oxygen isotopes on olivine from a variety of high-3He/4He OIB locations. To high precision, the Δ17O value of high-3He/4He olivines from Hawaii, Pitcairn, Baffin Island and Samoa, are indistinguishable from bulk mantle olivine (Δ17OBulk Mantle - Δ17OHigh 3He/4He olivine = -0.002 ± 0.004 (2 × SEM)‰). Thus, there is no resolvable oxygen isotope evidence for heterogeneous accretion in the high-3He/4He source. Modelling of mixing processes indicates that if an early-forming, oxygen-isotope distinct mantle did exist, either the anomaly was extremely small, or the anomaly was homogenised away by later mantle convection. The δ18O values of olivine with the highest 3He/4He ratios from a variety of OIB locations have a relatively uniform composition (∼5‰). This composition is intermediate to values associated with the depleted MORB mantle and the average mantle. Similarly, δ18O values of olivine from high-3He/4He OIB correlate with radiogenic isotope ratios of He, Sr, and Nd. Combined, this suggests that magmatic oxygen is sourced from the same mantle as other, more incompatible elements and that the intermediate δ18O value is a feature of the high-3He/4He mantle source. The processes responsible for the δ18O signature of high-3He/4He mantle are not certain, but δ18O-87Sr/86Sr correlations indicate that it may be connected to a predominance of a HIMU-like (high U/Pb) component or other moderate δ18O components recycled into the high-3He/4He source.

  12. MeV Neutron Production from Thermal Neutron Capture in 6Li Simulated With Geant4

    Science.gov (United States)

    Santoro, Valentina; DiJulio, Douglas D.; Bentley, Phillip M.

    2016-09-01

    Various Li compounds are commonly used at neutron facilities as neutron absorbers. These compounds provide one of the highest ratios of neutron attenuation to y- ray production. Unfortunately, the usage of these compounds can also give rise to fast neutron emission with energies up to almost 16 MeV. Historically, some details in this fast neutron production mechanism can be absent from some modeling packages under some optimization scenarios. In this work, we tested Geant4 to assess the performance of this simulation toolkit for the fast neutron generation mechanism. We compare the results of simulations performed with Geant4 to available measurements. The outcome of our study shows that results of the Geant4 simulations are in good agreement with the available measurements for 6 Li fast neutron production, and suitable for neutron instrument background evaluation at spallation neutron sources.

  13. Time-of-flight calibration of a 6Li glass epithermal neutron detector

    Science.gov (United States)

    Livingston; Saleh; Block; Brand

    2000-10-01

    The curing of Portland cement concrete involves the conversion of water from a free to a bound state. The process can be monitored nondestructively by measuring the shift in the neutron energy spectrum in the epithermal range (0.025-1 eV). A tuned array of 6Li glass detectors has been constructed with varying efficiencies over the epithermal energy range. To determine the efficiency of each detector as a function of neutron energy, it is necessary to calibrate it against a reference neutron spectrum. This was accomplished using a time-of-flight approach with a pulsed neutron beam produced at the Gaerttner LINAC Laboratory at Rensselaer Polytechnic Institute. With a neutron flight path of 25 m it was possible to determine the neutron detector efficiencies to an energy resolution of 11 microeV. The data showed good agreement with the detector design calculations.

  14. Investigation of α-cluster states in 13C via the (6Li,d) reaction

    CERN Document Server

    Rodrigues, M R D; Horodynski-Matsushigue, L B; Cunsolo, A; Cappuzzello, F; Duarte, J L M; Rodrigues, C L; Ukita, G M; Souza, M A; Miyake, H

    2010-01-01

    The 9Be(6Li,d)13C reaction was used to investigate possible α-cluster states in 13C. The reaction was measured at 25.5 MeV incident energy, employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. Ten out of sixteen known levels of 13C, up to 11 MeV of excitation, were observed and, due to the much improved energy resolution of 50 keV, at least three doublets could be resolved. This work presents a preliminary analysis of five of the most intensely populated states, also in comparison with the results of former transfer studies.

  15. Observation of repulsive Fermi polarons in a resonant mixture of ultracold ${}^6$Li atoms

    CERN Document Server

    Scazza, F; Massignan, P; Recati, A; Amico, A; Burchianti, A; Fort, C; Inguscio, M; Zaccanti, M; Roati, G

    2016-01-01

    We employ radio-frequency spectroscopy to investigate a polarized spin-mixture of ultracold ${}^6$Li atoms close to a broad Feshbach scattering resonance. Focusing on the regime of strong repulsive interactions, we observe well-defined coherent quasiparticles even for unitarity-limited interactions. We characterize the many-body system by extracting the key properties of repulsive Fermi polarons: the energy $E_+$, the effective mass $m^*$, the residue $Z$ and the decay rate $\\Gamma$. Above a critical interaction, $E_+$ is found to exceed the Fermi energy of the bath while $m^*$ diverges and even turns negative. Such findings reveal that the paramagnetic Fermi liquid state becomes thermodynamically unstable towards an energetically favored ferromagnetic phase.

  16. MeV Neutron Production from Thermal Neutron Capture in {6}^Li Simulated with Geant4

    CERN Document Server

    Santoro, Valentina; Bentley, Phillip M

    2015-01-01

    Various Li compounds are commonly used at neutron facilities as neutron absorbers. These compounds provide one of the highest ratios of neutron attenuation to $\\gamma$-ray production. Unfortunately, the usage of these compounds can also give rise to fast neutron emission with energies up to almost 16 MeV. Historically, some details in this fast neutron production mechanism can be absent from some modeling packages under some optimization scenarios. In this work, we tested Geant4 to assess the performance of this simulation toolkit for the fast neutron generation mechanism. We compare the results of simulations performed with Geant4 to available measurements. The outcome of our study shows that results of the Geant4 simulations are in good agreement with the available measurements for $^6$Li fast neutron production, and suitable for neutron instrument background evaluation at spallation neutron sources.

  17. Fusion excitation function measurement for 6Li+64Ni at near-barrier energies

    Directory of Open Access Journals (Sweden)

    Shaikh Md. Moin

    2015-01-01

    Full Text Available Total fusion excitation function has been measured for the reaction of weakly bound 6Li projectile on medium mass 64Ni target at energies near the Coulomb barrier of the system. Online characteristic γ-ray detection method has been used to identify and determine the cross sections of the residues. No suppression of total fusion cross section (σTF is observed at above barrier energies. But enhancement of measured cross section with respect to the one-dimensional barrier penetration model (1-DBPM calculation is observed at below barrier energies. The enhancement can not be explained by coupled channels calculation with dominant projectile and target excitations as well as one-neutron stripping reaction.

  18. Thermal neutron detection by entrapping 6LiF nanocrystals in siloxane scintillators

    Science.gov (United States)

    Carturan, S. M.; Marchi, T.; Maggioni, G.; Gramegna, F.; Degerlier, M.; Cinausero, M.; Dalla Palma, M.; Quaranta, A.

    2015-06-01

    Exploiting the long experience in design and production of scintillating mixtures based on siloxane matrices with combinations of primary dye and waveshifter, a first set of 6LiF loaded scintillator disks has been produced. The synthesis is herein described and reported, as well as preliminary results on their light response towards thermal neutrons. The preservation of transparency and mechanical integrity of the scintillator material is challenging when introducing the inorganic salt LiF which is a "foreign body" to the organic polysiloxane host matrix Different strategies such as synthesis of nanoparticles and surface functionalization have been pursued to succeed in the entrapment of the neutron converter whilst maintaining moderate light output, optical transparency and flexibility of the base scintillator.

  19. Reaction mechanisms in the {sup 6}Li + {sup 59}Co system

    Energy Technology Data Exchange (ETDEWEB)

    Souza, F.A. [Instituto de Fisica - Universidade de Sao Paulo, Departamento de Fisica Nuclear, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil)], E-mail: fsouza@dfn.if.usp.br; Beck, C. [Institut Pluridisciplinaire Hubert Curien, UMR 7178, CNRS-IN2P3 et Universite Louis Pasteur, Boite Postale 28, F-67037 Strasbourg, Cedex 2 (France); Carlin, N. [Instituto de Fisica - Universidade de Sao Paulo, Departamento de Fisica Nuclear, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil); Keeley, N. [CEA-Saclay DSM/IRFU/SPhN, F-91191 Gif sur Yvette Cedex (France); Neto, R. Liguori; Moura, M.M. de; Munhoz, M.G.; Del Santo, M.G.; Suaide, A.A.P.; Szanto, E.M.; Szanto de Toledo, A. [Instituto de Fisica - Universidade de Sao Paulo, Departamento de Fisica Nuclear, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil)

    2009-04-15

    The reactions induced by the weakly bound {sup 6}Li projectile interacting with the intermediate mass target {sup 59}Co were investigated. Light charged particles singles and {alpha}-d coincidence measurements were performed at the near barrier energies E{sub lab}=17.4, 21.5, 25.5 and 29.6 MeV. The main contributions of the different competing mechanisms are discussed. A statistical model analysis, Continuum-Discretized Coupled-Channels (CDCC) calculations and two-body kinematics were used as tools to provide information to disentangle the main components of these mechanisms. A significant contribution of the direct breakup was observed through the difference between the experimental sequential breakup cross section and the CDCC prediction for the non-capture breakup cross section.

  20. Fast neutron measurements with {sup 7}Li and {sup 6}Li enriched CLYC scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Giaz, A., E-mail: agnese.giaz@mi.infn.it [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Blasi, N.; Boiano, C.; Brambilla, S. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Camera, F. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Università degli Studi di Milano, Physics Department, Via Celoria 16, 20133 Milano (Italy); Cattadori, C. [INFN sezione di Milano Bicocca, Piazza della Scienza 3, 20125 Milano (Italy); Ceruti, S. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Università degli Studi di Milano, Physics Department, Via Celoria 16, 20133 Milano (Italy); Gramegna, F.; Marchi, T. [INFN Laboratori Nazionali di Legnaro, Viale dell’Università, 2, 35020 Legnaro, PD (Italy); Mattei, I. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Mentana, A. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Università degli Studi di Milano, Physics Department, Via Celoria 16, 20133 Milano (Italy); Million, B.; Pellegri, L. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Rebai, M. [Università degli Studi di Milano Bicocca, Physics Department, Piazza della Scienza 3, 20126 Milano (Italy); Riboldi, S. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Università degli Studi di Milano, Physics Department, Via Celoria 16, 20133 Milano (Italy); Salamida, F. [INFN sezione di Milano Bicocca, Piazza della Scienza 3, 20125 Milano (Italy); Tardocchi, M. [Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Via R. Cozzi 53, 2015 Milano (Italy)

    2016-07-21

    The recently developed Cs{sub 2}LiYCl{sub 6}:Ce (CLYC) crystals are interesting scintillation detectors not only for their gamma energy resolution (<5% at 662 keV) but also for their capability to identify and measure the energy of both gamma rays and fast/thermal neutrons. The thermal neutrons were detected by the {sup 6}Li(n,α)t reaction while for the fast neutrons the {sup 35}Cl(n,p){sup 35}S and {sup 35}Cl(n,α){sup 32}P neutron-capture reactions were exploited. The energy of the outgoing proton or α particle scales linearly with the incident neutron energy. The kinetic energy of the fast neutrons can be measured using both the Time Of Flight (TOF) technique and using the CLYC energy signal. In this work, the response to monochromatic fast neutrons (1.9–3.8 MeV) of two CLYC 1″×1″ crystals was measured using both the TOF and the energy signal. The observables were combined to identify fast neutrons, to subtract the thermal neutron background and to identify different fast neutron-capture reactions on {sup 35}Cl, in other words to understand if the detected particle is an α or a proton. We performed a dedicated measurement at the CN accelerator facility of the INFN Legnaro National Laboratories (Italy), where the fast neutrons were produced by impinging a proton beam (4.5, 5.0 and 5.5 MeV) on a {sup 7}LiF target. We tested a CLYC detector {sup 6}Li-enriched at about 95%, which is ideal for thermal neutron measurements, in parallel with another CLYC detector {sup 7}Li-enriched at more than 99%, which is suitable for fast neutron measurements.

  1. Fast neutron measurements with 7Li and 6Li enriched CLYC scintillators

    Science.gov (United States)

    Giaz, A.; Blasi, N.; Boiano, C.; Brambilla, S.; Camera, F.; Cattadori, C.; Ceruti, S.; Gramegna, F.; Marchi, T.; Mattei, I.; Mentana, A.; Million, B.; Pellegri, L.; Rebai, M.; Riboldi, S.; Salamida, F.; Tardocchi, M.

    2016-07-01

    The recently developed Cs2LiYCl6:Ce (CLYC) crystals are interesting scintillation detectors not only for their gamma energy resolution (<5% at 662 keV) but also for their capability to identify and measure the energy of both gamma rays and fast/thermal neutrons. The thermal neutrons were detected by the 6Li(n,α)t reaction while for the fast neutrons the 35Cl(n,p)35S and 35Cl(n,α)32P neutron-capture reactions were exploited. The energy of the outgoing proton or α particle scales linearly with the incident neutron energy. The kinetic energy of the fast neutrons can be measured using both the Time Of Flight (TOF) technique and using the CLYC energy signal. In this work, the response to monochromatic fast neutrons (1.9-3.8 MeV) of two CLYC 1″×1″ crystals was measured using both the TOF and the energy signal. The observables were combined to identify fast neutrons, to subtract the thermal neutron background and to identify different fast neutron-capture reactions on 35Cl, in other words to understand if the detected particle is an α or a proton. We performed a dedicated measurement at the CN accelerator facility of the INFN Legnaro National Laboratories (Italy), where the fast neutrons were produced by impinging a proton beam (4.5, 5.0 and 5.5 MeV) on a 7LiF target. We tested a CLYC detector 6Li-enriched at about 95%, which is ideal for thermal neutron measurements, in parallel with another CLYC detector 7Li-enriched at more than 99%, which is suitable for fast neutron measurements.

  2. Alpha cluster states in light nuclei populated through the (6Li,d) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Borello-Lewin, Thereza; Rodrigues, M.R.D.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F. [Universita di Catania (Italy). Istituto Nazionale di Fisica Nucleare. Lab. Nazionali del Sud; Ukita, Gilberto Mitsuo [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Fac. de Psicologia

    2011-07-01

    Full text: The alpha cluster correlation is an important concept in the nuclear physics of light nuclei. The main purpose of the research program in progress is the investigation of the alpha clustering phenomenon in (x{alpha}) and(x{alpha}+{nu}) nuclei through the ({sup 6}Li,d) alpha transfer reaction. In fact, there is scarce experimental information on the subject, in particular associated with resonant states predicted near (x{alpha}) and (x{alpha}+{nu}) thresholds. Measurements of the {sup 12},{sup 13}C({sup 6}Li,d) {sup 16},{sup 17}O reactions, at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique. The work is under way and an experimental energy resolution of 30 keV was obtained. Near the (4{alpha}) breakup threshold in {sup 16}O, three narrow alpha resonances, not previously measured, were detected, revealing important {alpha} + {sup 12}C(G.S.) components. One of these resonances corresponds to the known 0{sup +} state at 15.1 MeV[5] of excitation that has probably, according to Funaki et al., the gas like configuration of the 4{alpha} condensate state, with a very dilute density and a large component of {alpha} + {sup 12}C(Hoyle) configuration. As was already mentioned, our experimental information points to the necessity of including the {alpha} + {sup 12}C(G.S.) component in the wave function. (author)

  3. 3He spin filters for a thermal neutron triple axis spectrometer

    Science.gov (United States)

    Chen, W. C.; Armstrong, G.; Chen, Y.; Collett, B.; Erwin, R.; Gentile, T. R.; Jones, G. L.; Lynn, J. W.; McKenney, S.; Steinberg, J. E.

    2007-07-01

    We have tested two 3He neutron spin filters (NSF), one for the polarizer and one for the analyzer, in conjunction with a doubly focusing pyrolytic graphite (PG) monochromator on the state-of-the-art BT-7 thermal triple axis spectrometer (TAS) at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). This system will provide significantly better neutronic performance for polarization analysis over a conventional TAS with Heusler crystals. We discuss the scheme for employing NSFs on the TAS instrument, including the 3He cell design, spin-exchange optical pumping (SEOP) of these large 3He cells, and the holding fields on the spectrometer. Using Rb/K hybrid SEOP, we have produced 75% 3He polarization for the 11 cm diameter cells for TAS in less than two days.

  4. Core Plasma Characteristics of a Spherical Tokamak D-3He Fusion Reactor

    Institute of Scientific and Technical Information of China (English)

    Shi Bingren

    2005-01-01

    The magnetic fusion reactor using the advanced D-3He fuels has the advantage of much less-neutron productions so that the consequent damages to the first wall are less serious. If the establishment of this kind of reactor becomes realistic, the exploration of 3He on the moon will be largely motivated. Based on recent progresses in the spherical torus (ST) research, we have physically designed a D-3He fusion reactor using the extrapolated results from the ST experiments and also the present-day tokamak scaling. It is found that the reactor size significantly depends on the wall reflection coefficient of the synchrotron radiation and of the impurity contaminations.The secondary reaction between D-D that promptly leads to the D-T reaction producing 14 MeV neutrons is also estimated. Comparison of this D-3He ST reactor with the D-T reactor is made.

  5. Preconceptual engineering design for the APT {sup 3}He target/blanket concept

    Energy Technology Data Exchange (ETDEWEB)

    Mensink, D.L. [Babcock & Wilcox Co., Naval Nuclear Fuel Division, P.O. Box 785, Mt. Athos Rd., Lynchburg, Virginia 24505-0785 (United States); Rose, S.C. Jr. [Reactor Design and Analysis, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    1995-01-20

    A preconceptual engineering design has been developed for the {sup 3}He Target/Blanket (T/B) System for the Accelerator Production of Tritium Project. This concept uses an array of pressure tubes containing tungsten rods for the neutron spallation source and {sup 3}He gas contained in a metal tank and blanket tubes as the tritium production material. The engineering design is based on a physics model optimized for efficient tritium production. Principle engineering consideration were: provisions for cooling all materials including the {sup 3}He gas; containment of the gas and radionuclides; remote handling; material compatibility; minimization of {sup 3}He, D{sub 2}O, and activated waste; modularity; and manufacturability. The design provides a basis for estimating the cost to implement the system.

  6. Cryopol: a superconducting magnetostatic cavity for a sup 3 He neutron spin filter

    CERN Document Server

    Dreyer, J; Bourgeat-Lami, E; Lelievre-Berna, E; Pujol, S; Thomas, F; Thomas, M; Tasset, F

    2000-01-01

    We present a device called 'Cryopol' that provides a clean magnetic environment for a sup 3 He spin filter cell, even in the presence of strong magnetic stray fields like those of a superconducting magnet.

  7. Hyperpolarized 3He MRI and 81mKr SPECT in chronic obstructive pulmonary disease

    DEFF Research Database (Denmark)

    Stavngaard, Trine; Søgaard, Lise; Mortensen, J;

    2005-01-01

    was to compare ventilation imaging methods in 26 patients with chronic obstructive pulmonary disease (COPD) and nine lung healthy volunteers. METHODS: HP 3He MRI, 81mKr single-photon emission computed tomography (SPECT), high-resolution computed tomography (HRCT) and pulmonary function tests were performed...... visual defect score (r=0.80, ppulmonary function test and HRCT). The defect scores were largest on 81mKr SPECT (the score on HP 3He MRI...... was one-third less than that on 81mKr SPECT), but the difference was reduced after normalisation for different breathing depths (HP 3He MRI at total lung capacity; 81mKr SPECT at tidal breathing at functional residual capacity). CONCLUSION: HP 3He MRI provides detailed ventilation distribution images...

  8. Isospin effects in the exclusive dp -> 3He{\\pi}+{\\pi}- reaction

    CERN Document Server

    Mielke, M; Chiladze, D; Dymov, S; Fritzsch, C; Gebel, R; Goslawski, P; Hartmann, M; Kacharava, A; Khoukaz, A; Kulessa, P; Lorentz, B; Mersmann, T; Mikirtychiants, S; Ohm, H; Papenbrock, M; Rausmann, T; Serdyuk, V; Ströher, H; Täschner, A; Valdau, Y; Wilkin, C

    2014-01-01

    The differential cross section for the exclusive dp -> 3He{\\pi}+{\\pi}- reaction has been measured with high resolution and large statistics over a large fraction of the backward 3He hemisphere at the excess energy 265 MeV using the COSY-ANKE magnetic spectrometer. Though the well-known ABC enhancement is observed in the {\\pi}+{\\pi}- spectrum, the differences detected between the {\\pi}+3He and {\\pi}-3He invariant-mass distributions show that there must be some isospin-one {\\pi}{\\pi} production even at relatively low excess energies. The invariant-mass differences are modeled in terms of the sequential decay N*(1440) -> Delta(1232){\\pi} -> N{\\pi}{\\pi}.

  9. Recent advancements of wide-angle polarization analysis with 3He neutron spin filters

    Science.gov (United States)

    Chen, W. C.; Gentile, T. R.; Ye, Q.; Kirchhoff, A.; Watson, S. M.; Rodriguez-Rivera, J. A.; Qiu, Y.; Broholm, C.

    2016-09-01

    Wide-angle polarization analysis with polarized 3He based neutron spin filters (NSFs) has recently been employed on the Multi-Axis Crystal Spectrometer (MACS) at the National Institute of Standards and Technology Center for Neutron Research (NCNR). Over the past several years, the apparatus has undergone many upgrades to address the fundamental requirements for wide angle polarization analysis using spin exchange optical pumping based 3He NSFs. In this paper, we report substantial improvements in the on-beam-line performance of the apparatus and progress toward routine user capability. We discuss new standard samples used for 3He NSF characterization and the flipping ratio measurement on MACS. We further discuss the management of stray magnetic fields produced by operation of superconducting magnets on the MACS instrument, which can significantly reduce the 3He polarization relaxation time. Finally, we present the results of recent development of horseshoe-shaped wide angle cells.

  10. SANS study of phase separation in solid {sup 3}He-{sup 4}He

    Energy Technology Data Exchange (ETDEWEB)

    Koster, J.P.; Nagler, S.E.; Adams, E.D. [Florida Univ., Gainesville, FL (United States). Dept. of Physics; Wignall, G.D. [Oak Ridge National Lab., TN (United States). Solid State Div.

    1994-12-31

    Small angle neutron scattering has been used to study phase separation in a quantum alloy, solid {sup 3}He{sub x}-{sup 4}He{sub 1{minus}x}. The onset of phase separation is marked by a dramatic increase in the measured scattering. A simple interpretation of the results suggests that the late-stage phase separation kinetics are dominated by an increase in the concentration of {sup 3}He atoms in preexisting precipitate regions.

  11. {sup 3}He spectrum at small atmospheric depths for different geomagnetic cutoff values

    Energy Technology Data Exchange (ETDEWEB)

    Papini, P. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Grimani, C. [Perugia Univ. (Italy)]|[INFN, Perugia (Italy); Stephens, S.A. [Tata Institute of Fundamental Research, Bombay (International Commission on Radiation Units and Measurements)

    1995-09-01

    It is carried out a calculation to determine the energy spectra of secondary {sup 3}He at small atmospheric depths. It is produced in the spallation reaction of primary helium and heavier nuclei in the overlying atmosphere. It is examined the effect of the geomagnetic cut-off on the spectral shape of the secondary {sup 3}He nuclei. The calculations are being carried out for both solar minimum and maximum periods. Results from these calculations will be presented at the Conference.

  12. Nonlinear Density Enhancement of 3He in the Sun's Central Core

    Institute of Scientific and Technical Information of China (English)

    DU Jiu-Lin

    2000-01-01

    A flow velocity field that has a “sink” drives the core 3He nuclear reaction diffusion system to instability to jump from the original state to the new one, in which the total amour of 3He is enhanced. This alters the original competition between pp I and pp Ⅱ +pp Ⅲ chains, and thus potentially suppresses the production of both the 7Be and 8B neutrino fluxes.

  13. Photoassociation spectroscopy of long-range molecular states below the 2s + 3p 6Li2 asymptote

    Science.gov (United States)

    Gross, Christian; Chaudhuri, Saptarishi; Gan, Jaren; Dieckmann, Kai

    2015-05-01

    We present photoassociation spectra of high-lying vibrational states of the interatomic potentials correlating to the 2s + 3p asymptote of 6Li2 . Starting from an atomic cloud in a magneto-optical trap we first drive a free-to-bound transition into a molecular bound state using a tunable ultra-violet laser. Thereafter we ionize these long-range molecules using a 532 nm laser and detect the resulting ions with a channeltron. We determine the absolute positions of the transitions with MHz precision utilizing a frequency comb based calibration. Lithium dimers are extensively studied theoretically using various models and methods. Spectroscopic measurements are crucial to test and benchmark these methods and are available for various electronic states and inter-nuclear distances of 6Li2 molecule. Our study provides the first experimental observation of long-range states of the 2s + 3p asymptote of 6Li2 .

  14. Terrestrial cosmogenic 3He: where are we 30 years after its discovery?

    Science.gov (United States)

    Blard, Pierre-Henri; Pik, Raphaël; Farley, Kenneth A.; Lavé, Jérôme; Marrocchi, Yves

    2016-04-01

    It is now 30 years since cosmogenic 3He has been detected for the first time in a terrestrial sample (Kurz, 1986). 3He is now a widely used geochemical tool in many fields of Earth sciences: volcanology, tectonics, paleoclimatology. 3He has the advantage to have a high "production rate" to "detection limit" ratio, allowing surfaces as young as hundred of years to be dated. Although its nuclear stability implies several limitations, it moreover represents a useful alternative to 10Be in mafic environments. This contribution is a review of the progresses that have been accomplished since this discovery, and discuss strategies to improve both the accuracy and the precision of this geochronometer. 1) Measurement of cosmogenic 3He Correction of magmatic 3He. To estimate the non-cosmogenic magmatic 3He, Kurz (1986) invented a two steps method involving crushing of phenocrysts (to analyze the isotopic ratio of the magmatic component), followed by a subsequent melting of the sample, to extract the remaining components, including the cosmogenic 3He: 3Hec = 3Hemelt -4Hemelt x (3He/4He)magmatic (1) Several studies suggested that the preliminary crushing may induce a loss of cosmogenic 3He (Hilton et al., 1993; Yokochi et al., 2005; Blard et al., 2006), implying an underestimate of the cosmogenic 3He measurement. However, subsequent work did not replicate these observations (Blard et al., 2008; Goerhing et al., 2010), suggesting an influence of the used apparatus. An isochron method (by directly melting several phenocrysts aliquots) is an alternative to avoid the preliminary crushing step (Blard and Pik, 2008). Atmospheric contamination. Protin et al. (in press) provides robust evidences for a large and irreversible contamination of atmospheric helium on silicate surfaces. This unexpected behavior may reconcile the contrasted observations about the amplitude of crushing loss. This undesirable atmospheric contamination is negligible if grain fractions smaller than 150 mm are

  15. Tritium production in a sphere of /sup 6/LiD irradiated by 14-MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Hemmendinger, A.; Ragan, C.E.; Shunk, E.R.; Ellis, A.N.; Anaya, J.M.; Wallace, J.M.

    1978-10-01

    The specific production of tritium in samples of /sup 6/LiH and /sup 7/LiH embedded in a 600-mm-diam sphere of /sup 6/LiD irradiated by a central source of 14-MeV neutrons was determined by measuring the activity of the hydrogen evolved from the samples of each isotope at each of five different radii in the /sup 6/LiD assembly. The entire process of decomposing the LiH, transferring the evolved gas into counters, and determining the decay rate was standardized by processing LiH samples irradiated by thermal neutrons for which the /sup 6/Li(n,..cap alpha..) cross section is well known. The specific production of tritium in /sup 6/LiH and /sup 7/LiH (embedded samples) and the activation of radiochemical detector foils of /sup 45/Sc, /sup 89/Y, /sup 90/Zr, /sup 169/Tm, /sup 191/Ir /sub 373/, /sup 193/Ir /sub 627/, /sup 197/Au, /sup 235/U, and /sup 238/U placed at various positions in the /sup 6/LiD sphere were calculated and compared with the experimental data. One- and three-dimensional Monte Carlo and S/sub n/ neutron-transport calculations were performed. The most reliable (three-dimensional Monte Carlo) calculation is in reasonable agreement with both the tritium-production and the radiochemical-activation data. The existing discrepancies between calculation and experiment appear largely attributable to uncertainties in some tritium-production and radiochemical-activation cross sections. 15 references.

  16. 6LiF Semiconductor Sandwich Spectrometer for Fast Neutron Spectrum Measurement%用于快中子能谱测量的6LiF夹心半导体谱仪

    Institute of Scientific and Technical Information of China (English)

    蒋勇; 李俊杰; 张涛; 范晓强; 郑春

    2012-01-01

    A detector of 6LiF semiconductor sandwich spectrometer was designed and manufactured. Characteristics of the spectrometer were tested in the fast neutron critical assembly. Measurement principle, configuration of detector and electronic circuit were introduced. Fast neutron spectrum was measured using the 6LiF semiconductor sandwich spectrometer. When the detector's 6 LiF mass thickness is 186 μg/cm2, the spectrometer's energy resolution is 363 keV in the thermal neutron field. For this spectrometer, the optimal fathomable neutron energy range is 0. 3-7. 5 MeV, and the background counts only take possession of 1 % in this area.%本文介绍了6 LiF夹心谱仪的测量原理、自行设计研制的6LiF夹心半导体谱仪探头结构及电子学系统组成等.在热中子场中测试了夹心谱仪的性能,获得了α粒子峰、T粒子峰及“和”峰在多道上的位置与能量分辨率,并用T粒子与“和”峰两个能量点的峰位对谱仪系统进行了能量刻度.分别用效应探头和本底探头测量了临界装置表面的效应谱和本底谱,当效应探头采用的6 LiF镀层质量厚度为186 μg/cm2时,6 LiF夹心谱仪对热中子的能量分辨率为363 keY,测量中子最佳能区为0.3~7.5 MeV,在该能区内,本底谱约占1%.

  17. Zeeman Relaxation of Cold Atomic Iron and Nickel in Collisions with 3He

    CERN Document Server

    Johnson, Cort; Brahms, Nathan; Doyle, John M; Kleppner, Daniel; Greytak, Thomas J

    2010-01-01

    We have measured the ratio of the diffusion cross-section to the angular momentum reorientation cross-section in the colliding Fe-3He and Ni-3He systems. Nickel (Ni) and iron (Fe) atoms are introduced via laser ablation into a cryogenically cooled experimental cell containing cold (< 1 K) 3He buffer gas. Elastic collisions rapidly cool the translational temperature of the ablated atoms to the helium temperature. The cross-section ratio is extracted by measuring the decays of the atomic Zeeman sublevels. For our experimental conditions, thermal energy is comparable to the Zeeman splitting. As a result, thermal excitations between Zeeman sublevels significantly impact the observed decay. To determine the cross-section ratio accurately, we introduce a model of Zeeman state dynamics that includes thermal excitations. We find the cross-section ratio for Ni-3He = 5 x 10^3 and Fe-3He <= 3 x 10^3 at 0.75 K in a 0.8 T magnetic field. These measurements are interpreted in the context of submerged shell suppressio...

  18. Coherent deeply virtual Compton scattering off 3He and neutron generalized parton distributions

    Directory of Open Access Journals (Sweden)

    Rinaldi Matteo

    2014-06-01

    Full Text Available It has been recently proposed to study coherent deeply virtual Compton scattering (DVCS off 3He nuclei to access neutron generalized parton distributions (GPDs. In particular, it has been shown that, in Impulse Approximation (IA and at low momentum transfer, the sum of the quark helicity conserving GPDs of 3He, H and E, is dominated by the neutron contribution. This peculiar result makes the 3He target very promising to access the neutron information. We present here the IA calculation of the spin dependent GPD H See Formula in PDF of 3He. Also for this quantity the neutron contribution is found to be the dominant one, at low momentum transfer. The known forward limit of the IA calculation of H See Formula in PDF , yielding the polarized parton distributions of 3He, is correctly recovered. The extraction of the neutron information could be anyway non trivial, so that a procedure, able to take into account the nuclear effects encoded in the IA analysis, is proposed. These calculations, essential for the evaluation of the coherent DVCS cross section asymmetries, which depend on the GPDs H,E and H See Formula in PDF , represent a crucial step for planning possible experiments at Jefferson Lab.

  19. p +d →3He+γ reaction with pionless effective field theory

    Science.gov (United States)

    Nematollahi, H.; Bayegan, S.; Mahboubi, N.; Arani, M. Moeini

    2016-11-01

    We study the proton radiative capture by a deuteron with the pionless effective field theory [EFT(π / )] formalism. The calculation of the p d →3Heγ amplitude is considered for the incoming doublet and quartet channels leading to the formation of a 3He. The strong and Coulomb scattering amplitudes for the proton-deuteron (p d ) scattering are included in this study. In this calculation, the properly normalized 3He wave function has been used at each order. We evaluate both M 1 and E 1 transitions in the p d →3Heγ process up to NLO. We calculate the total cross section for the p d →3Heγ process based on the cluster-configuration space and compare it with the experimental data. The cross section results are presented for the incoming proton with the energy 0.5 ≤E ≤3 MeV where the lower and upper limits are chosen for the treatment of Coulomb effects perturbatively and the EFT(π / ) breakdown scale, respectively. No three-body force is needed to renormalize observables up to NLO other than those we have introduced in the p d scattering amplitudes.

  20. Oxygen-sensitive {sup 3}He-MRI in bronchiolitis obliterans after lung transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Gast, Klaus K. [Klinikum der Johannes Gutenberg-Universitaet, Klinik und Poliklinik fuer diagnostische und interventionelle Radiologie, Mainz (Germany); Biedermann, Alexander [Klinikum der Johannes Gutenberg-Universitaet, 3. Medizinische Klinik, Pulmonologie, Mainz (Germany); Herweling, Annette [Klinikum der Johannes Gutenberg-Universitaet, Klinik fuer Anaesthesiologie, Mainz (Germany); Schreiber, Wolfgang G. [Klinikum der Johannes Gutenberg-Universitaet, Klinik und Poliklinik fuer diagnostische und interventionelle Radiologie, MR-Physik, Mainz (Germany); Schmiedeskamp, Joerg [Max-Planck-Institut fuer Polymerforschung, Mainz (Germany); Mayer, Eckhard [Klinikum der Johannes Gutenberg-Universitaet, Klinik fuer Herz-, Thorax- und Gefaesschirurgie, Mainz (Germany); Heussel, Claus P. [Abteilung fuer Radiologie, Thoraxklinik Heidelberg, Heidelberg (Germany); Markstaller, Klaus; Eberle, Balthasar [Inselspital/Universitaetsspital, Klinik fuer Anaesthesiologie, Bern (Switzerland); Kauczor, Hans-Ulrich [Radiologie, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany)

    2008-03-15

    Oxygen-sensitive {sup 3}He-MRI was studied for the detection of differences in intrapulmonary oxygen partial pressure (pO{sub 2}) between patients with normal lung transplants and those with bronchiolitis obliterans syndrome (BOS). Using software developed in-house, oxygen-sensitive {sup 3}He-MRI datasets from patients with normal lung grafts (n = 8) and with BOS (n = 6) were evaluated quantitatively. Datasets were acquired on a 1.5-T system using a spoiled gradient echo pulse sequence. Underlying diseases were pulmonary emphysema (n = 10 datasets) and fibrosis (n = 4). BOS status was verified by pulmonary function tests. Additionally, {sup 3}He-MRI was assessed blindedly for ventilation defects. Median intrapulmonary pO{sub 2} in patients with normal lung grafts was 146 mbar compared with 108 mbar in patients with BOS. Homogeneity of pO2 distribution was greater in normal grafts (standard deviation pO2 34 versus 43 mbar). Median oxygen decrease rate during breath hold was higher in unaffected patients (-1.75 mbar/s versus -0.38 mbar/s). Normal grafts showed fewer ventilation defects (5% versus 28%, medians). Oxygen-sensitive {sup 3}He-MRI appears capable of demonstrating differences of intrapulmonary pO2 between normal lung grafts and grafts affected by BOS. Oxygen-sensitive {sup 3}He-MRI may add helpful regional information to other diagnostic techniques for the assessment and follow-up of lung transplant recipients. (orig.)

  1. The Destruction of 3He by Rayleigh-Taylor Instability on the First Giant Branch

    CERN Document Server

    Eggleton, P P; Lattanzio, J C

    2006-01-01

    Low-mass stars, ~1-2 solar masses, near the Main Sequence are efficient at producing 3He, which they mix into the convective envelope on the giant branch and distribute into the Galaxy by way of envelope loss. This process is so efficient that it is difficult to reconcile the observed cosmic abundance of 3He with the predictions of Big Bang nucleosynthesis. In this paper we find, by modeling a red giant with a fully three-dimensional hydrodynamic code and a full nucleosynthetic network, that mixing arises in the supposedly stable and radiative zone between the hydrogen-burning shell and the base of the convective envelope. This mixing is due to Rayleigh-Taylor instability within a zone just above the hydrogen-burning shell. In this zone the burning of the 3He left behind by the retreating convective envelope is predominantly by the reaction 3He + 3He -> 4He + 2p, a reaction which, untypically for stellar nuclear reactions, {\\it lowers} the mean molecular weight, leading to a local minimum. This local minimum ...

  2. Neutron Diffuse Reflectometry of Magnetic Thin Films with a 3He Analyzer

    Science.gov (United States)

    Chen, Wangchun; O'Donovan, Kevin; Borchers, Julie

    2005-03-01

    Polarized neutron reflectometry (PNR) is a powerful probe that characterizes the magnetization depth profile and magnetic domains in magnetic thin films. Although the conventionally used supermirrors are well-matched for specular PNR, they have limited angular acceptance and hence are impractical for complete characterization of the magnetic off-specular scattering where polarization analysis for diffusely reflected neutrons is required. Polarized ^3He gas, produced by optical pumping, can be used to polarize or analyze neutron beams because of the strong spin dependence of the neutron absorption cross section for ^3He. Here we report efficient polarization analysis of diffusely reflected neutrons in a reflectometry geometry using a polarized ^3He analyzer in conjunction with a position-sensitive detector (PSD). We obtained spin-resolved two-dimensional Qx-Qz reciprocal space maps for a patterned array of Co antidots in both the saturated and the demagnetized states. The preliminary results for a patterned amorphous bilayer, Gd40Fe60/ Tb55Fe45, measured with a ^3He analyzer and a PSD will also be discussed. Using the spin exchange optical pumping method we have achieved record high ^3He polarizations of 76% on the neutron beam line where we measured an initial analyzing efficiency of 0.97 and a neutron transmission for the desired spin state of 0.45.

  3. Results on Double-polarization Asymmetries in Quasielastic Scattering from Polarized 3He

    Energy Technology Data Exchange (ETDEWEB)

    Sulkosky, Vincent A. [Univ. of Virginia, Charlottesville, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-03-01

    The 3He nucleus has become extremely important in the investigation of the neutron’s spin structure. When polarized, 3He acts as an effective polarized neutron target and hence facilitates our understanding of the neutron’s internal structure. However, to be used in this manner, our understanding of the internal structure of 3He is of extreme importance. As the precision of experiments has improved, the extraction of polarized neutron information from 3He leads to an ever larger share of the systematic uncertainty for these experiments. In these proceedings, I present a precise measurement of beam-target asymmetries in the and reactions. The former process is a uniquely sensitive probe of hadron dynamics in 3He and the structure of the underlying electromagnetic currents. The measurements have been performed around the quasi-elastic peak at Q2 = 0.25 (GeV/c)2 and 0.35 (GeV/c)2 for recoil momenta up to 270 MeV/c. The experimental apparatus, analysis and results were presented together with a comparison to state-of-the art Faddeev calculations.

  4. A study of the proton spectra following the capture of $K^-$ in $^6$Li and $^{12}$C with FINUDA

    CERN Document Server

    Agnello, M; Benussi, L; Bertani, M; Bhang, H C; Bianco, S; Bonomi, G; Botta, E; Bregant, M; Bressani, Tullio; Bufalino, S; Busso, L; Calvo, D; Camerini, P; Cerello, P; Dalena, B; Mori, F D; D'Erasmo, G; Santo, D D; Elia, D; Fabbri, F L; Faso, D; Feliciello, A; Filippi, A; Filippini, V; Fini, R A; Fiore, E M; Fujioka, H; Gianotti, P; Grion, N; Hartmann, O; Krasnoperov, A V; Lenti, V; Lucherini, V; Manzari, V; Marcello, S; Maruta, T; Mirfakhraee, N; Morra, O; Nagae, T; Olin, A; Outa, H; Pace, E; Pallotta, M; Palomba, M; Pantaleo, A; Panzarasa, A; Paticchio, V; Piano, S; Pompili, F; Rui, R; Simonetti, G; Tereshchenko, V V; Tomassini, S; Toyoda, A; Wheadon, R; Zenoni, A

    2006-01-01

    Momenta spectra of protons emitted following the capture of $K^-$ in $^6$Li and $^{12}$C have been measured with 1% resolution. The $^{12}$C spectrum is smooth whereas for $^6$Li a well defined peak appears at about 500 MeV/$c$. The first observation of a structure in this region was identified as a strange tribaryon or, possibly, a $\\bar K$-nuclear state. The peak is correlated with a $\\pi^-$ coming from $\\Sigma^-$ decay in flight, selected by setting momenta larger than 275 MeV/$c$. The $\\Sigma^-$ could be produced, together with a 500 MeV/$c$ proton, by the capture of a $K^-$ in a deuteron-cluster substructure of the $^6$Li nucleus. The capture rate for such a reaction is $(1.62\\pm 0.23_{stat} ^{+0.71}_{-0.44}(sys))%/K^-_{stop}$, in agreement with the existing observations on $^4$He targets and with the hypothesis that the $^6$Li nucleus can be interpreted as a $(d+\\alpha)$ cluster.

  5. Systematics of the breakup probability function for {sup 6}Li and {sup 7}Li projectiles

    Energy Technology Data Exchange (ETDEWEB)

    Capurro, O.A., E-mail: capurro@tandar.cnea.gov.ar [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); Pacheco, A.J.; Arazi, A. [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Carnelli, P.F.F. [CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, 25 de Mayo y Francia, B1650BWA San Martín, Buenos Aires (Argentina); Fernández Niello, J.O. [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, 25 de Mayo y Francia, B1650BWA San Martín, Buenos Aires (Argentina); and others

    2016-01-15

    Experimental non-capture breakup cross sections can be used to determine the probability of projectile and ejectile fragmentation in nuclear reactions involving weakly bound nuclei. Recently, the probability of both type of dissociations has been analyzed in nuclear reactions involving {sup 9}Be projectiles onto various heavy targets at sub-barrier energies. In the present work we extend this kind of systematic analysis to the case of {sup 6}Li and {sup 7}Li projectiles with the purpose of investigating general features of projectile-like breakup probabilities for reactions induced by stable weakly bound nuclei. For that purpose we have obtained the probabilities of projectile and ejectile breakup for a large number of systems, starting from a compilation of the corresponding reported non-capture breakup cross sections. We parametrize the results in accordance with the previous studies for the case of beryllium projectiles, and we discuss their systematic behavior as a function of the projectile, the target mass and the reaction Q-value.

  6. Benchmark calculation of n-3H and p-3He scattering

    CERN Document Server

    Viviani, M; Lazauskas, R; Carbonell, J; Fonseca, A C; Kievsky, A; Marcucci, L E; Rosati, S

    2011-01-01

    The n-3H and p-3He elastic phase-shifts below the trinucleon disintegration thresholds are calculated by solving the 4-nucleon problem with three different realistic nucleon-nucleon interactions (the I-N3LO model by Entem and Machleidt, the Argonne v18 potential model, and a low-k model derived from the CD-Bonn potential). Three different methods -- Alt, Grassberger and Sandhas, Hyperspherical Harmonics, and Faddeev-Yakubovsky -- have been used and their respective results are compared. For both n-3H and p-3He we observe a rather good agreement between the three different theoretical methods. We also compare the theoretical predictions with the available experimental data, confirming the large underprediction of the p-3He analyzing power.

  7. Feasibility study of a sup 3 He-magnetometer for neutron electric dipole moment experiments

    CERN Document Server

    Borisov, Y; Leduc, M; Lobashev, V; Otten, E W; Sobolev, Y

    2000-01-01

    We report on a sup 3 He-magnetometer capable of detecting tiny magnetic field fluctuations of less than 10 sup - sup 1 sup 4 T in experiments for measuring the electric dipole moment (EDM) of the neutron. It is based on the Ramsey technique of separated oscillating fields and uses nuclear spin-polarized sup 3 He gas which is stored in two vessels of V approx =10 l in a sandwich-type arrangement around the storage bottle for ultra-cold neutrons (UCN). The gas is polarized by means of optical pumping in a separate, small discharge cell at pressures around 0.5 mbar and is then expanded into the actual magnetometer volume. To detect the polarization of sup 3 He gas at the end of the storage cycle the gas is pumped out by means of an oil-diffusion pump and compressed again into the discharge cell where optical detection of nuclear polarization is used.

  8. Antisymmetry and channel coupling contributions to the absorption for $p + \\alpha /d + ^{3}He$

    CERN Document Server

    Cooper, S G

    1997-01-01

    To understand recently established empirical p + alpha potentials, RGM calculations followed by inversion are made to study contributions of the d + 3He reaction channels and deuteron distortion effects to the p + alpha potential. An equivalent study of the d + 3He potential is also presented. The contributions of exchange non-locality to the absorption are simulated by including an phenomenological imaginary potential in the RGM. These effects alone strongly influence the shape of the imaginary potentials for both p + alpha and d + 3He. The potentials local-equivalent to the fully antisymmetrised-coupled channels calculations have a significant parity-dependence in both real and imaginary components, which for p + alpha is qualitatively similar to that found empirically. The effects on the potentials of the further inclusion of deuteron distortion are also presented. The inclusion of a spin-orbit term in the RGM, adds additional terms to the phase-equivalent potential, most notably the comparatively large im...

  9. Green's function theory for the Cheng-Schick model of 3He-4He mixtures

    Science.gov (United States)

    Siemann, R. P.; Boukahil, A.; Huber, D. L.

    2014-08-01

    In this paper, we outline a theory for the thermodynamic properties of 3He-4He mixtures in the neighborhood of the critical line and the tricritical point (TCP). The theory utilizes the Cheng-Schick (CS) lattice gas model where both the 3He and 4He atoms are treated as quantum particles on a lattice. The analysis is based on Green's function approach. Results are presented for the ordering susceptibility and the thermal averages of the occupation numbers of 3He and 4He atoms. We derive a self-consistent equation for the ordering susceptibility and use it to calculate the critical line and locate the TCP. Our findings are compared with the predictions obtained from high temperature series expansions, mean field theory and the random phase approximation (RPA).

  10. Modelling the effect of 3He in direct drive capsule implosions

    Science.gov (United States)

    Garbett, W. J.; Horsfield, C. J.; Herrmann, H. W.; Langenbrunner, J. R.; Cooley, J. H.; Wilson, D. C.; Evans, S. C.; Sedillo, T. J.; Rubery, M. S.; Drew, D.; Mack, J. M.; Young, C. S.; Kyrala, G. A.; Frenje, J.; Glebov, V. Yu

    2010-08-01

    D3He fuels are often used in ICF implosion experiments, either as a surrogate for DT to restrict the output neutron yield, or to produce protons for use in diagnosis of core conditions. Recent experiments have suggested that capsules filled with D3He do not behave as expected, but that both proton and neutron yields are anomalously degraded relative to the pure D2 case. We have performed direct drive implosion experiments using the Omega laser to examine the effect of 3He on DT-filled glass capsules. The use of DT fuel allows reaction history measurements to be obtained using the Gas Cherenkov diagnostic (GCD). It was hoped that the detailed information provided by GCD measurements would complement existing measurements to constrain modelling. We present recent modelling and analysis of the experiments using radiation-hydrocode simulations, and explore some of the hypotheses proposed to explain the results.

  11. Implications of new High 3He/4He Values from the Samoan Hotspot

    Science.gov (United States)

    Jackson, M. G.; Kurz, M. D.; Hart, S. R.; Workman, R.

    2005-12-01

    We report new olivine phenocryst helium measurements from Ofu Island, American Samoa; the 3He/4He ratios range from 19.5 to 33.7 times atmospheric (R/Ra), significantly expanding the observed range for Samoa. The highest 3He/4He ratio of 33.7 Ra was measured in olivines from an ankaramite dike. Relatively high helium concentrations (4.4*108 cc/g) in this sample, crushing and fusion measurements, coupled with sampling from a roadcut exposure, all ensure that the isotope ratio is not affected by in situ cosmogenic 3He. A second basaltic dike yielded a 3He/4He ratio of 29.6 Ra, and measurements on 9 other basalt samples from Ofu range from 19.5 to 26.4 Ra. Previous high 3He/4He measurements (~25 Ra) from the Samoan hotspot were also obtained from basaltic dikes, but were from Tutuila Island (Farley et al., 1992). The new high 3He/4He ratios from Samoa are similar in magnitude to the high ratios found at Iceland (~37 Ra) and Hawaii (~35 Ra). However, the Ofu basalts have 87Sr/86Sr > 0.7044, which is significantly more radiogenic than Iceland or Hawaii. The combined Sr-He isotopic data are broadly consistent with mixing between an enriched mantle source (EM2) and the putative common high 3He/4He component (FOZO, as best represented by Baffin Island Picrites, Stuart et al., 2003). Assuming that the overall isotopic variations are produced by mixing processes, we attempt to place constraints on the relative helium concentrations in the FOZO, EM2 and Depleted MORB mantle (DMM) endmembers. In addition to using the shape of the plausible mixing lines, we employ new estimates for the trace element concentrations in the DMM and Samoan EM2 sources (Workman et al., 2004; Workman and Hart, 2005) to get at relative helium concentrations in these reservoirs. We assume that high 3He/4He basalts from the mid-Atlantic ridge North of Iceland (Schilling et al., 1999, and others) are a mixture between DMM and FOZO. We further assume that the N. Iceland ridge-FOZO and Ofu-FOZO mixing

  12. Rotational spectrum of the NH3-He van der Waals complex

    Science.gov (United States)

    Surin, L.; Schnell, M.

    2016-12-01

    The interaction between ammonia and helium has attracted considerable interest over many years, partly because of the observation of interstellar ammonia. The rate coefficients of NH3-He scattering are an important ingredient for numerical modeling of astrochemical environments. Another, though quite different application in which the NH3-He interaction can play an important role is the doping of helium clusters with NH3 molecules to perform high-resolution spectroscopy. Such experiments are directed on the detection of non-classical response of molecular rotation in helium clusters addressing fundamental questions related to the microscopic nature of superfluidity. High-resolution spectroscopy on the NH3-He complex is an important tool for increasing our understanding of intermolecular forces between NH3 and He.

  13. First doubly polarised photoproduction on {sup 3}He at the photon beam of MAMI

    Energy Technology Data Exchange (ETDEWEB)

    Aguar Bartolome, Patricia

    2010-11-15

    A first experiment with a polarised {sup 3}He target was carried out in July 2009 at the MAMI accelerator in Mainz in a photon energy range between 200 MeV and 800 MeV. The aim of this measurement was to investigate the Gerasimov-Drell-Hearn sum rule on the neutron. The use of the data obtained with the polarised {sup 3}He target, compared to existing data on the deuteron, gives a complementary and more direct access to the neutron, due to the spin structure of the {sup 3}He. The measurement of the helicity dependence of the inclusive total photoabsorption cross section required a beam of tagged circularly polarised photons incident on the longitudinally polarised {sup 3}He target. The data were taken using the 4{pi} Crystal Ball photon spectrometer in combination with TAPS as a forward wall and complemented by a threshold Cherenkov detector used to on-line suppress the background from electromagnetic events. The development and preparation of the different components of the {sup 3}He experimental setup was an important part of this work and are described in detail in this thesis. The detector system and the analysis method were tested by the measurement of the unpolarised total inclusive photoabsorption cross section on liquid hydrogen. The results obtained are in good agreement with previous published data. Preliminary results of the unpolarised total photoabsorption cross section, as well as the helicity dependent photoabsorption cross section difference on {sup 3}He compared with several theoretical models will also be presented. (orig.)

  14. The Origin and Acceleration of 3He and Heavy Ions in the 2000 July 14 Event

    Institute of Scientific and Technical Information of China (English)

    Gui-Ping Wu; Guang-Li Huang; Yu-Hua Tang; Yu Dai

    2007-01-01

    According to the evolutionary properties of the flare, halo coronal mass ejection (CME), enrichments of 3He ions in the energy range of 3.5-26 MeV nucl-1 and Ne, Mg, Si and Fe ions in the energy range of 8.5-15 MeV nucl-1, we argue that the 3He and heavy ions originate in the middle corona (~0.1-1 R⊙) with well-connected open field lines to the Earth,where the magnetic reconnection leads to acceleration of the electrons and the production of type-Ⅲ burst during the decay phase of the soft X-ray emission. The acceleration of 3He and heavy ions may have been accomplished in two stages: first H-He ion-ion hybrid waves may be easily excited by the energetic electron beams produced in the middle corona, and these waves are preferentially absorbed by 3He and heavy ions due to their frequency being near the fundamental gyro frequency of the 3He ions and harmonic gyro frequency of Ne, Mg, Si and Fe ions. These preheated ions escape into interplanetary space along the open field lines and may be further accelerated to tens of MeV nucl-1 by CME-driven shock. The theoretical calculations show that the 3He and heavy ions may be accelerated to the energy of ~ MeV nucl-1 by the ion-ion hybrid waves and be further accelerated to the energy of ~ 100 MeV nucl- 1 by the shock wave: these are basically consistent with the observations.

  15. Boron-coated straws as a replacement for 3He-based neutron detectors

    Science.gov (United States)

    Lacy, Jeffrey L.; Athanasiades, Athanasios; Sun, Liang; Martin, Christopher S.; Lyons, Tom D.; Foss, Michael A.; Haygood, Hal B.

    2011-10-01

    US and international government efforts to equip major seaports with large area neutron detectors, aimed to intercept the smuggling of nuclear materials, have precipitated a critical shortage of 3He gas. It is estimated that the annual demand of 3He for US security applications alone is more than the worldwide supply. This is strongly limiting the prospects of neutron science, safeguards, and other applications that rely heavily on 3He-based detectors. Clearly, alternate neutron detection technologies that can support large sensitive areas, and have low gamma sensitivity and low cost must be developed. We propose a low-cost technology based on long copper tubes (straws), coated on the inside with a thin layer of 10B-enriched boron carbide ( 10B 4C). In addition to the high abundance of boron on Earth and low cost of 10B enrichment, the boron-coated straw (BCS) detector offers distinct advantages over conventional 3He-based detectors, and alternate technologies such as 10BF 3 tubes and 10B-coated rigid tubes. These include better distribution inside moderator assemblies, many-times faster electronic signals, no pressurization, improved gamma-ray rejection, no toxic or flammable gases, and ease of serviceability. We present the performance of BCS detectors dispersed in a solid plastic moderator to address the need for portal monitoring. The design adopts the outer dimensions of currently deployed 3He-based monitors, but takes advantage of the small BCS diameter to achieve a more uniform distribution of neutron converter throughout the moderating material. We show that approximately 63 BCS detectors, each 205 cm long, distributed inside the moderator, can match or exceed the detection efficiency of typical monitors fitted with a 5 cm diameter 3He tube, 187 cm long, pressurized to 3 atm.

  16. Characterizing a sewage plume using the 3H-3He dating technique

    Science.gov (United States)

    Shapiro, Stephanie Dunkle; LeBlanc, Denis; Schlosser, Peter; Ludin, Andrea

    1999-01-01

    An extensive 3H-3He study was performed to determine detailed characteristics of a regional flow system and a sewage plume over a distance of 4 km in a sand and gravel aquifer at Otis Air Base in Falmouth, Massachusetts. 3H-3He ages increase with depth in individual piezometer clusters and with distance along flowpaths. However, the age gradient with depth (Δt/Δz) is smaller in the plume than that in the regional waters, due to the intense recharge in the infiltration beds. The 1960s bomb peak of tritium in precipitation is archived longitudinally along a flowline through the main axis of the plume and vertically in individual piezometer clusters. On the eastern side of the sampling area, where water from Ashumet Pond forces plume water deeper into the flow system, 3H-3He ages are young at depth because the 3H-3He "clock" is reset due to outgassing of helium in the pond. A reconstruction of the tritium input functions for the regional and plume samples shows that there is no offset in the peak [3H]+[3Hetrit] concentrations for the plume and regional water, indicating that the water from supply wells for use on the base is young. The 3H-3He ages and detergent concentrations in individual wells are consistent with the beginning of use of detergents and the time period when their concentrations in sewage would have been greatest. Ages and hydraulic properties calculated using the 3H-3He data compare well with those from previous investigations and from particle-tracking simulations.

  17. D and $^{3}He$ production in $\\sqrt{s}$ = 130 GeV Au + Au collisions

    CERN Document Server

    Adler, C; Allgower, C; Amonett, J; Anderson, B D; Anderson, M; Averichev, G S; Balewski, J T; Barannikova, O Yu; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bichsel, H; Bland, L C; Blyth, C O; Bonner, B E; Boucham, A; Brandin, A B; Cadman, R V; Caines, H; Calderón de la Barca-Sanchez, M; Cardenas, A; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chattopadhyay, S; Chen, M L; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Cormier, T M; Cramer, J G; Crawford, H J; De Mello, M; Deng, W S; Derevshchikov, A A; Didenko, L; Draper, J E; Dunin, V B; Dunlop, J C; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Finch, E; Fisyak, Yu; Flierl, D; Foley, Kenneth J; Fu, J; Gagunashvili, N D; Gans, J; Gaudichet, L; Germain, M; Geurts, F J M; Ghazikhanian, V; Grabski, J; Grachov, O A; Greiner, D E; Grigoriev, V; Guedon, M; Guschin, E; Hallman, T J; Hardtke, D; Harris, J W; Heffner, M; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Humanic, T J; Hümmler, H; Igo, G; Ishihara, A; Ivanshin, Yu I; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E; Kaneta, M; Kaplan, M; Keane, D; Kisiel, A; Klay, J L; Klein, S R; Klyachko, A A; Konstantinov, A S; Kotchenda, L; Kovalenko, A D; Krämer, M; Kravtsov, P; Krüger, K; Kuhn, C; Kulikov, A V; Kunde, G J; Kunz, C L; Kutuev, R K; Kuznetsov, A A; Lakehal-Ayat, L; Lamas-Valverde, J; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lebedev, A; LeCompte, T J; Lednicky, R; Leontiev, V M; Le Vine, M J; Li, Q; Li, Q; Lindenbaum, S J; Lisa, M A; Ljubicic, T; Llope, W J; Lo Curto, G; Long, H; Longacre, R S; López-Noriega, M; Love, W A; Lynn, D; Majka, R; Margetis, S; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnik, Yu M; Meshchanin, A P; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mitchell, J; Moiseenko, V A; Moltz, D; Moore, C F; Morozov, V; De Moura, M M; Munhoz, M G; Mutchler, G S; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Oson, D; Paic, G; Pandey, S U; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevozchikov, V; Peryt, W; Petrov, V A; Platner, E D; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potrebenikova, E V; Prindle, D J; Pruneau, C A; Radomski, S; Rai, G; Ravel, O; Ray, R L; Razin, S V; Reichhold, D M; Reid, J G; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Roy, C; Russ, D; Rykov, V L; Sakrejda, I; Sandweiss, J; Saulys, A C; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schröder, L S; Schüttauf, A; Schweda, K; Seger, J E; Seliverstov, D M; Seyboth, P; Shahaliev, E; Shestermanov, K E; Shimansky, S S; Shvetcov, V S; Skoro, G P; Smirnov, N; Snellings, R; Sowinski, J; Spinka, H M; Srivastava, B; Stephenson, E J; Stock, Reinhard; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Struck, C; Suaide, A A P; Sugarbaker, E R; Suire, C; Sumbera, M; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Takahashi, J; Tang, A H; Thomas, J H; Tikhomirov, V; Trainor, T A; Trentalange, S; Tokarev, M; Tonjes, M B; Trofimov, V; Tsai, O; Turner, K; Ullrich, T S; Underwood, D G; Van Buren, G; Van der Molen, A; Vanyashin, A V; Vasilevski, I M; Vasilev, A N; Vigdor, S E; Voloshin, S A; Wang, F; Ward, H; Watson, J W; Wells, R; Wenaus, T J; Westfall, G D; Whitten, C; Wieman, H H; Willson, R; Wissink, S W; Witt, R; Xu, N; Xu, Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yokosawa, A; Yurevich, V I; Zanevsky, Yu V; Zborovský, I; Zhang, H; Zhang, W M; Zoulkarneev, R; Zubarev, A N; 10.1103/PhysRevLett.87.262301

    2001-01-01

    The first measurements of light antinucleus production in Au + Au collisions at the Relativistic Heavy-Ion Collider are reported. The observed production rates for d and /sup 3/He are much larger than in lower energy nucleus-nucleus collisions. A coalescence model analysis of the yields indicates that there is little or no increase in the antinucleon freeze-out volume compared to collisions at CERN SPS energy. These analyses also indicate that the 3He freeze-out volume is smaller than the d freeze-out volume. (22 refs).

  18. Final State Interaction Effects in pol 3He(pol e,e'p)

    CERN Document Server

    Carasco, C C; Merle, P; Bartsch, P; Baumann, D; Böhm, R; Bosnar, D; Ding, M; Distler, M O; Friedrich, J M; Golak, J; Glöckle, W; Hauger, M; Heil, W; Jennewein, P; Jourdan, J; Kamada, H; Klein, A; Köhl, M; Krygier, K W; Merkel, H; Müller, U; Neuhausen, R; Nogga, A; Normand, C; Otten, E W; Pospischil, T; Potokar, M; Rohe, D; Schmieden, H; Schmiedeskamp, J; Seimetz, M; Sick, I; Sirca, S; Skibinski, S; Testa, G; Walcher, T; Warren, G; Weis, M; Witala, H; Wöhrle, H; Zeier, M; Normand, Ch.; Pospischil, Th.; Walcher, Th.

    2003-01-01

    Asymmetries in quasi-elastic pol 3He(pol e,e'p) have been measured at a momentum transfer of 0.67 (GeV/c)^2 and are compared to a calculation which takes into account relativistic kinematics in the final state and a relativistic one-body current operator. With an exact solution of the Faddeev equation for the 3He-ground state and an approximate treatment of final state interactions in the continuum good agreement is found with the experimental data.

  19. High-Sensitivity Measurement of 3He-4He Isotopic Ratios for Ultracold Neutron Experiments

    CERN Document Server

    Mumm, H P; Bauder, W; Abrams, N; Deibel, C M; Huffer, C R; Huffman, P R; Schelhammer, K W; Swank, C M; Janssens, R; Jiang, C L; Scott, R H; Pardo, R C; Rehm, K E; Vondrasek, R; O'Shaughnessy, C M; Paul, M; Yang, L

    2016-01-01

    Research efforts ranging from studies of solid helium to searches for a neutron electric dipole moment require isotopically purified helium with a ratio of 3He to 4He at levels below that which can be measured using traditional mass spectroscopy techniques. We demonstrate an approach to such a measurement using accelerator mass spectroscopy, reaching the 10e-14 level of sensitivity, several orders of magnitude more sensitive than other techniques. Measurements of 3He/4He in samples relevant to the measurement of the neutron lifetime indicate the need for substantial corrections. We also argue that there is a clear path forward to sensitivity increases of at least another order of magnitude.

  20. Heat Transfer in 3He -4He Mixtures in Cylindrical Geometry

    Science.gov (United States)

    Nemchenko, K.; Rogova, S.; Vikhtinskaya, T.

    2017-02-01

    The paper presents the results of theoretical studies of the transport processes that take place in the newly proposed experiments on study of a vibrating quartz fork in superfluid 3He -4He mixtures. In addition to known mechanisms of energy loss from a vibrating quartz fork such as first sound radiation or interaction with thermal excitations, two more mechanisms specific for 3He -4He mixtures are proposed and studied in the paper. The relative contribution of these mechanisms: second sound and effective diffusion, is considered, and experimental conditions under which these mechanisms become effective are discussed.

  1. Zero-field magnetic order in the boundary layers of /sup 3/He on Grafoil

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, L.J.; Thomson, A.L.; Gould, C.M.; Bozler, H.M.; Weichman, P.B.; Cross, M.C.

    1989-04-03

    The low-field NMR spectra of /sup 3/He boundary layers on exfoliated graphite show collective modes for T<1 mK. We measure the amplitude and frequency for these modes with the static H/sub 0/ field applied parallel to the graphite planes and varying continuously between 0 and 15 G. One of the modes extrapolates to a nonzero frequency and amplitude as the field is dropped to zero. We interpret these nonzero intercepts as an indication of zero-field magnetic order in the /sup 3/He boundary layers.

  2. High-efficiency microstructured semiconductor neutron detectors for direct {sup 3}He replacement

    Energy Technology Data Exchange (ETDEWEB)

    Fronk, R.G., E-mail: rfronk@ksu.edu [S.M.A.R.T. Laboratory, Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS 66506 (United States); Bellinger, S.L.; Henson, L.C. [S.M.A.R.T. Laboratory, Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS 66506 (United States); Huddleston, D.E. [Electronics Design Laboratory, Kansas State University, Manhattan, KS 66506 (United States); Ochs, T.R. [S.M.A.R.T. Laboratory, Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS 66506 (United States); Sobering, T.J. [Electronics Design Laboratory, Kansas State University, Manhattan, KS 66506 (United States); McGregor, D.S. [S.M.A.R.T. Laboratory, Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS 66506 (United States)

    2015-04-11

    High-efficiency Microstructured Semiconductor Neutron Detectors (MSNDs) have been tiled and arranged in a cylindrical form factor in order to serve as a direct replacement to aging and increasingly expensive {sup 3}He gas-filled proportional neutron detectors. Two 6-in long by 2-in diameter cylinders were constructed and populated with MSNDs which were then directly compared to a 4 atm Reuter Stokes {sup 3}He detector of the same dimensions. The Generation 1 MSND-based {sup 3}Helium-Replacement (HeRep Mk I) device contained sixty-four 1-cm{sup 2} active-area MSNDs, each with an intrinsic neutron detection efficiency of approximately 7%. A Generation 2 device (the HeRep Mk II) was populated with thirty 4-cm{sup 2} active-area MSNDs, with an intrinsic thermal neutron detection efficiency of approximately 30%. The MSNDs of each HeRep were integrated to count as a single device. The {sup 3}He proportional counter and the HeRep devices were tested while encased in a cylinder of high-density polyethylene measuring a total of 6-in by 9-in. The {sup 3}He counter and the HeRep Mk II were each placed 1 m from a 54-ng {sup 252}Cf source and tested for efficiency. The {sup 3}He proportional counter had a net count rate of 17.13±0.10 cps at 1 m. The HeRep Mk II device had a net count rate of 17.60±0.10 cps, amounting to 102.71±2.65% of the {sup 3}He gas counter while inside of the moderator. Outside of moderator, the {sup 3}He tube had a count rate of 3.35±0.05 cps and the HeRep Mk II device reported 3.19±05, amounting to 95.15±9.04% of the {sup 3}He neutron detector.

  3. Solar Sources of $^{3}$He-rich Solar Energetic Particle Events in Solar Cycle 24

    OpenAIRE

    Nitta, Nariaki V.; Mason, Glenn M.; Wang, Linghua; Cohen, Christina M. S.; Wiedenbeck, Mark E.

    2015-01-01

    Using high-cadence extreme-ultraviolet (EUV) images obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we investigate the solar sources of 26 $^{3}$He-rich solar energetic particle (SEP) events at $\\lesssim$1 MeV nucleon$^{-1}$ that were well-observed by the Advanced Composition Explorer during solar cycle 24. Identification of the solar sources is based on the association of $^{3}$He-rich events with type III radio bursts and electron events as observ...

  4. SEOP polarized 3He Neutron Spin Filters for the JCNS user program

    Science.gov (United States)

    Babcock, Earl; Salhi, Zahir; Theisselmann, Tobias; Starostin, Denis; Schmeissner, Johann; Feoktystov, Artem; Mattauch, Stefan; Pistel, Patrick; Radulescu, Aurel; Ioffe, Alexander

    2016-04-01

    Over the past several years the JCNS has been developing in-house applications for neutron polarization analysis (PA). These methods include PA for separation of incoherent from coherent scattering in soft matter studies (SANS), and online polarization for analysis for neutron reflectometry, SANS, GISANS and eventually spectroscopy. This paper will present an overview of the user activities at the JCNS at the MLZ and gives an overview of the polarization 3He methods and devices used. Additionally we will summarise current projects which will further support the user activities using polarised 3He spin filters.

  5. EXISTENCE AND REGULARITY OF SOLUTIONS TO MODEL FOR LIQUID MIXTURE OF 3HE-4HE

    Institute of Scientific and Technical Information of China (English)

    Luo Hong; Pu Zhilin

    2012-01-01

    Existence and regularity of solutions to model for liquid mixture of 3He-4He is considered in this paper.First,it is proved that this system possesses a unique global weak solution in H1(Ω,C × R) by using Galerkin method.Secondly,by using an iteration procedure,regularity estimates for the linear semigroups,it is proved that the model for liquid mixture of 3He-4He has a unique solution in Hk(Ω,C × R) for all k ≥ 1.

  6. Benchmark calculation of p-3H and n-3He scattering

    CERN Document Server

    Viviani, M; Lazauskas, R; Fonseca, A C; Kievsky, A; Marcucci, L E

    2016-01-01

    p-3H and n-3He scattering in the energy range above the n-3He but below the d-d thresholds is studied by solving the 4-nucleon problem with a realistic nucleon-nucleon interaction. Three different methods -- Alt, Grassberger and Sandhas, Hyperspherical Harmonics, and Faddeev-Yakubovsky -- have been employed and their results for both elastic and charge-exchange processes are compared. We observe a good agreement between the three different methods, thus the obtained results may serve as a benchmark. A comparison with the available experimental data is also reported and discussed.

  7. Towards {sup 6}Li-{sup 40}K ground state molecules

    Energy Technology Data Exchange (ETDEWEB)

    Brachmann, Johannes Felix Simon

    2013-02-08

    The production of a quantum gas with strong long - range dipolar interactions is a major scientific goal in the research field of ultracold gases. In their ro - vibrational ground state Li-K dimers possess a large permanent dipole moment, which could possibly be exploited for the realization of such a quantum gas. A production of these molecules can be achieved by the association of Li and K at a Feshbach resonance, followed by a coherent state transfer. In this thesis, detailed theoretical an experimental preparations to achieve state transfer by means of Stimulated Raman Adiabatic Passage (STIRAP) are described. The theoretical preparations focus on the selection of an electronically excited molecular state that is suitable for STIRAP transfer. In this context, molecular transition dipole moments for both transitions involved in STIRAP transfer are predicted for the first time. This is achieved by the calculation of Franck-Condon factors and a determination of the state in which the {sup 6}Li-{sup 40}K Feshbach molecules are produced. The calculations show that state transfer by use of a single STIRAP sequence is experimentally very well feasible. Further, the optical wavelengths that are needed to address the selected states are calculated. The high accuracy of the data will allow to carry out the molecular spectroscopy in a fast and efficient manner. Further, only a comparatively narrow wavelength tuneability of the spectroscopy lasers is needed. The most suitable Feshbach resonance for the production of {sup 6}Li-{sup 40}K molecules at experimentally manageable magnetic field strengths is occurring at 155 G. Experimentally, this resonance is investigated by means of cross-dimensional relaxation. The application of the technique at various magnetic field strengths in the vicinity of the 155 G Feshbach resonance allows a determination of the resonance position and width with so far unreached precision. This reveals the production of molecules on the atomic side

  8. Study of response of {sup 3}He detectors to monoenergetic neutrons; Etude des reponses des detecteurs a {sup 3}He par des neutrons monoenergetiques

    Energy Technology Data Exchange (ETDEWEB)

    Abanades, A. [European Organization for Nuclear Research, Geneva (CERN); Andriamonje, S.; Arnould, H.; Barreau, G.; Bercion, M. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France); Casagrande, F.; Cennini, P. [European Organization for Nuclear Research, Geneva (CERN); Del Moral, R. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France); Gonzales, E. [European Organization for Nuclear Research, Geneva (CERN); Lacoste, V.; Pdemay, G.; Pravikoff, M.S. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France); TARC Collaboration under leadership of C. Rubbia

    1997-06-01

    In the search of a hybrid system (the coupling of the particle accelerator to an under-critical reactor) for radioactive waste transmutation the TARC (Transmutation by Adiabatic Resonance Crossing) program has been developed. Due to experimental limitations, the time-energy relation at higher neutron energies, particularly, around 2 MeV, which is an important domain for TARC, cannot be applied. Consequently the responses of the {sup 3}He ionization neutron detector developed for TARC experiment have been studied using a fast monoenergetic neutron source. The neutrons were produced by the interaction of the proton delivered by Van de Graaff accelerator of CENBG. The originality of the detector consists in its structure of three series of electric conductors which are mounted around the anode: a grid ensuring the detector proportionality, a cylindrical suit of alternating positive voltage and grounded wires aiming at eliminating the radial end effects, serving as veto and two cylinders serving as end plugs to eliminate the perpendicular end effects. Examples of anode spectra conditioned (in anticoincidence) by the mentioned vetoes are given. One can see the contribution of the elastic scattering from H and {sup 3}He. By collimating the neutron beam through a borated polyethylene system it was possible to obtain a mapping of the detector allowing the study of its response as a function of the irradiated zones (anode and grid) 2 refs. This paper is related to TRN FR9810178

  9. Nuclear effects and neutron structure in deeply virtual Compton scattering off 3He

    CERN Document Server

    Rinaldi, Matteo

    2014-01-01

    The study of nuclear generalized parton distributions (GPDs) could be a crucial achievement of hadronic physics since they open new ways to obtain new information on the structure of bound nucleons, in particular, to access the neutron GPDs. Here, the results of calculations of 3He GPDs in Impulse Approximation are presented. The calculation of the sum of GPDs H + E, and "tilde H", with the correct limits, will be shown. These quantities, at low momentum transfer, are largely dominated by the neutron contribution so that 3He is an ideal target for these kind of studies. Nevertheless the extraction of neutron information from future 3He data could be non trivial. A procedure, which takes into account nuclear effects encoded in IA, is presented. The calculation of H,E and "tilde H" allows also to evaluate the cross section asymmetries for deeply virtual compton scattering at Jefferson Lab kinematics. Thanks to these observations, DVCS off 3He could be an ideal process to access the neutron information in the ne...

  10. Two dimensional sup 3 He adsorbed on Grafoil plated with a bilayer of HD

    CERN Document Server

    Casey, A J

    2001-01-01

    sup 3 He films adsorbed on graphite preplated with a bilayer of hydrogen deuteride were studied by heat capacity measurements, in a nuclear demagnetisation cryostat down to temperatures below 1mK. The work focused on several areas of interest in 2D sup 3 He. Firstly coverages approaching solidification were investigated. Here we observed an apparent divergence in the effective mass of the sup 3 He quasi-particle as it approached solidification at a density in agreement with that predicted by the sq root 7x sq root 7 commensurate phase. We interpret this in terms of a Mott-Hubbard transition between a 2D Fermi liquid and a magnetically disordered solid occurring via the Brinkman-Rice scenario. We also observe finite temperature corrections to the linear heat capacity of the formT sup 2 going over to TlnT. Further investigations were carried out into solid coverages in which sup 3 He forms a two-dimensional quantum solid of spin 1/2 particles whose magnetism is influenced by reduced dimensionality, exchange and...

  11. Energy spectra of 3He-rich solar energetic particles associated with coronal waves

    Science.gov (United States)

    Bučík, R.; Innes, D. E.; Mason, G. M.; Wiedenbeck, M. E.

    2016-11-01

    In addition to their anomalous abundances, 3He-rich solar energetic particles (SEPs) show puzzling energy spectral shapes varying from rounded forms to power laws where the later are characteristics of shock acceleration. Solar sources of these particles have been often associated with jets and narrow CMEs, which are the signatures of magnetic reconnection involving open field. Recent reports on new associations with large-scale EUV waves bring new insights on acceleration and transport of 3He-rich SEPs in the corona. We examined energy spectra for 32 3He-rich SEP events observed by ACE at L1 near solar minimum in 2007-2010 and compared the spectral shapes with solar flare signatures obtained from STEREO EUV images. We found the events with jets or brightenings tend to be associated with rounded spectra and the events with coronal waves with power laws. This suggests that coronal waves may be related to the unknown second stage mechanism commonly used to interpret spectral forms of 3He-rich SEPs.

  12. Energy spectra of 3He-rich solar energetic particles associated with coronal waves

    CERN Document Server

    Bucik, R; Mason, G M; Wiedenbeck, M E

    2016-01-01

    In addition to their anomalous abundances, 3He-rich solar energetic particles (SEPs) show puzzling energy spectral shapes varying from rounded forms to power laws where the later are characteristics of shock acceleration. Solar sources of these particles have been often associated with jets and narrow CMEs, which are the signatures of magnetic reconnection involving open field. Recent reports on new associations with large-scale EUV waves bring new insights on acceleration and transport of 3He-rich SEPs in the corona. We examined energy spectra for 32 3He-rich SEP events observed by ACE at L1 near solar minimum in 2007-2010 and compared the spectral shapes with solar flare signatures obtained from STEREO EUV images. We found the events with jets or brightenings tend to be associated with rounded spectra and the events with coronal waves with power laws. This suggests that coronal waves may be related to the unknown second stage mechanism commonly used to interpret spectral forms of 3He-rich SEPs.

  13. Spectroscopic issues in optical polarization of 3He gas for Magnetic Resonance Imaging of human lungs

    Science.gov (United States)

    Dohnalik, T.; Głowacz, B.; Olejniczak, Z.; Pałasz, T.; Suchanek, M.; Wojna, A.

    2013-10-01

    The Magnetic Resonance Imaging (MRI) of human lungs for diagnostic purposes became possible by using nuclear spin hyperpolarized noble gases, such as 3He. One of the methods to polarize 3He is the Metastability Exchange Optical Pumping (MEOP), which up to now has been performed at low pressure of about 1 mbar and in low magnetic field below 0.1 T (standard conditions). The equilibrium nuclear polarization can reach up to 80%, but it is dramatically reduced during the subsequent gas compression to the atmospheric pressure that is necessary for the lungs examination. Further polarization losses occur during the transportation of the gas to the hospital scanner. It was shown recently that up to 50% polarization can be obtained at elevated pressure exceeding 20 mbar, by using magnetic field higher than 0.1 T (nonstandard conditions). Therefore, following the construction of the low-field MEOP polarizer located in the lab, a dedicated portable unit was developed, which uses the magnetic field of the 1.5 T MR medical scanner and works in the continuous-flow regime. The first in Poland MRI images of human lungs in vivo were obtained on the upgraded to 3He resonance frequency Siemens Sonata medical scanner. An evident improvement in the image quality was achieved when using the new technique. The paper shows how spectroscopic measurements of 3He carried out in various experimental conditions led both to useful practical results and to significant progress in understanding fundamental processes taking place during MEOP.

  14. Ignition access in a D-{sup 3}He helical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mitarai, Osamu [Kyushu Tokai Univ., Kumamoto (Japan)

    2003-04-01

    Ignition access in a D-{sup 3}He helical reactor is studied based on 0-dimensional particle and power balance equations for deuterium, tritium, helium-3, alpha ash, proton ash, electron density and temperature. The calculations are based on the following experimental facts observed in LHD. (author)

  15. Association of 3He-Rich Solar Energetic Particles with Large-Scale Coronal Waves

    CERN Document Server

    Bucik, Radoslav; Mason, Glenn M; Wiedenbeck, Mark E

    2016-01-01

    Small 3He-rich solar energetic particle (SEP) events have been commonly associated with extreme-ultraviolet (EUV) jets and narrow coronal mass ejections (CMEs) which are believed to be the signatures of magnetic reconnection involving field lines open to interplanetary space. The elemental and isotopic fractionation in these events are thought to be caused by processes confined to the flare sites. In this study we identify 32 3He-rich SEP events observed by the Advanced Composition Explorer near the Earth during the solar minimum period 2007-2010 and examine their solar sources with the high resolution Solar Terrestrial Relations Observatory (STEREO) EUV images. Leading the Earth, STEREO-A provided for the first time a direct view on 3He-rich flares, which are generally located on the Sun's western hemisphere. Surprisingly, we find that about half of the 3He-rich SEP events in this survey are associated with large-scale EUV coronal waves. An examination of the wave front propagation, the source-flare distribu...

  16. Separable interactions and liquid 3He : V. Phase diagram in the presence of a Hubbard interaction

    NARCIS (Netherlands)

    Capel, H.W.; Nijhoff, F.W.; Breems, A. den

    1986-01-01

    A comparison is made between the various extrema of the Landau expansion of liquid 3He derived in a previous paper. As an application the phase diagram is investigated in the presence of an external magnetic field assuming that the Hubbard interaction is small as compared to the pairing interaction

  17. Solar Sources of $^{3}$He-rich Solar Energetic Particle Events in Solar Cycle 24

    CERN Document Server

    Nitta, Nariaki V; Wang, Linghua; Cohen, Christina M S; Wiedenbeck, Mark E

    2015-01-01

    Using high-cadence extreme-ultraviolet (EUV) images obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we investigate the solar sources of 26 $^{3}$He-rich solar energetic particle (SEP) events at $\\lesssim$1 MeV nucleon$^{-1}$ that were well-observed by the Advanced Composition Explorer during solar cycle 24. Identification of the solar sources is based on the association of $^{3}$He-rich events with type III radio bursts and electron events as observed by Wind. The source locations are further verified in EUV images from the Solar and Terrestrial Relations Observatory, which provides information on solar activities in the regions not visible from the Earth. Based on AIA observations, $^{3}$He-rich events are not only associated with coronal jets as emphasized in solar cycle 23 studies, but also with more spatially extended eruptions. The properties of the $^{3}$He-rich events do not appear to be strongly correlated with those of the source regions. As in the previous...

  18. The effects of nuclear structure on generalized parton distributions of 3He

    CERN Document Server

    Scopetta, S

    2005-01-01

    The effect of the nuclear medium on generalized parton distributions (GPDs) is studied for the 3He nucleus, through a realistic microscopic analysis. In Impulse Approximation, Fermi motion and binding effects, evaluated by modern potentials, are found to be larger than in the forward case and very sensitive to the details of nuclear structure at short distances.

  19. Deep mixing of 3He: reconciling Big Bang and stellar nucleosynthesis.

    Science.gov (United States)

    Eggleton, Peter P; Dearborn, David S P; Lattanzio, John C

    2006-12-08

    Low-mass stars, approximately 1 to 2 solar masses, near the Main Sequence are efficient at producing the helium isotope 3He, which they mix into the convective envelope on the giant branch and should distribute into the Galaxy by way of envelope loss. This process is so efficient that it is difficult to reconcile the low observed cosmic abundance of 3He with the predictions of both stellar and Big Bang nucleosynthesis. Here we find, by modeling a red giant with a fully three-dimensional hydrodynamic code and a full nucleosynthetic network, that mixing arises in the supposedly stable and radiative zone between the hydrogen-burning shell and the base of the convective envelope. This mixing is due to Rayleigh-Taylor instability within a zone just above the hydrogen-burning shell, where a nuclear reaction lowers the mean molecular weight slightly. Thus, we are able to remove the threat that 3He production in low-mass stars poses to the Big Bang nucleosynthesis of 3He.

  20. 3He(α,γ7Be cross section measured using complementary techniques

    Directory of Open Access Journals (Sweden)

    Carmona-Gallardo M.

    2014-03-01

    Full Text Available The astrophysical S-factor for the 3He(α,γ7Be reaction plays an important role in the Solar Standard Model and in the Big Bang Nucleosynthesis scenario. The advances from two recent experiments performed using complementary techniques at center of mass (C.M. energies between 1 and 3 MeV are discussed.

  1. SOLAR SOURCES OF {sup 3}He-RICH SOLAR ENERGETIC PARTICLE EVENTS IN SOLAR CYCLE 24

    Energy Technology Data Exchange (ETDEWEB)

    Nitta, Nariaki V. [Lockheed Martin Advanced Technology Center, Dept/A021S, B/252, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Mason, Glenn M. [Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States); Wang, Linghua [Institute of Space Physics and Applied Technology, Peking University, Beijing 100871 (China); Cohen, Christina M. S. [California Institute of Technology, Pasadena, CA 91125 (United States); Wiedenbeck, Mark E., E-mail: nitta@lmsal.com, E-mail: glenn.mason@jhuapl.edu, E-mail: wanglhwang@gmail.com, E-mail: cohen@srl.caltech.edu, E-mail: mark.e.wiedenbeck@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2015-06-20

    Using high-cadence EUV images obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we investigate the solar sources of 26 {sup 3}He-rich solar energetic particle events at ≲1 MeV nucleon{sup −1} that were well-observed by the Advanced Composition Explorer during solar cycle 24. Identification of the solar sources is based on the association of {sup 3}He-rich events with type III radio bursts and electron events as observed by Wind. The source locations are further verified in EUV images from the Solar and Terrestrial Relations Observatory, which provides information on solar activities in the regions not visible from the Earth. Based on AIA observations, {sup 3}He-rich events are not only associated with coronal jets as emphasized in solar cycle 23 studies, but also with more spatially extended eruptions. The properties of the {sup 3}He-rich events do not appear to be strongly correlated with those of the source regions. As in the previous studies, the magnetic connection between the source region and the observer is not always reproduced adequately by the simple potential field source surface model combined with the Parker spiral. Instead, we find a broad longitudinal distribution of the source regions extending well beyond the west limb, with the longitude deviating significantly from that expected from the observed solar wind speed.

  2. Compounds of 6Li and natural Li for EPR dosimetry in photon/neutron mixed radiation fields.

    Science.gov (United States)

    Lund, E; Gustafsson, H; Danilczuk, M; Sastry, M D; Lund, A

    2004-05-01

    Formates and dithionates of 6Li, enriched and 7Li in natural composition of Li offer a possibility to measure the absorbed dose from photons and thermal neutrons in a mixed radiation field for instance at a boron neutron capture therapy (BNCT) facility. Tests with formates and dithionates of enriched 6Li and lithium compounds with natural composition have been performed at the BNCT facility at Studsvik, Sweden. Irradiations have been performed at 3 cm depth in a Perspex phantom in a fluence rate of thermal neutrons 1.8 x 10(9) n cm(-2) s(-1). The compounds were also irradiated in a pure X-ray field from a 4MV linear accelerator at 5 cm depth in a phantom with accurately determined absorbed doses. The signal intensity and shape was investigated within 3 h after the irradiation. A single line spectrum attributed to the CO2- radical was observed after irradiation of lithium formate. An increase in line width occurring after neutron irradiation in comparison with photon irradiation of the 6Li sample was attributed to dipolar broadening between CO2- radicals trapped in the tracks of the alpha particles. A spectrum due to the SO3- radical anion was observed after irradiation of lithium dithionate. The signal amplitude increased using the 6Li in place of the Li with natural composition of isotopes, in studies with low energy X-ray irradiation. Due to the decreased line width, caused by the difference in g(N) and I between the isotopes, the sensitivity with 6Li dithionate may be enhanced by an order of magnitude compared to alanine dosimetry. After comprehensive examination of the different combinations of compounds with different amounts of 6Li and 7Li regarding dosimetry, radiation chemistry and EPR properties these dosimeter material might be used for dose determinations at BNCT treatments and for biomedical experiments. Interesting properties of the radical formation might be visible due to the large difference in ionization density of neutrons compared to photons.

  3. (3)He MRI in healthy volunteers: preliminary correlation with smoking history and lung volumes.

    Science.gov (United States)

    Guenther, D; Eberle, B; Hast, J; Lill, J; Markstaller, K; Puderbach, M; Schreiber, W G; Hanisch, G; Heussel, C P; Surkau, R; Grossmann, T; Weiler, N; Thelen, M; Kauczor, H U

    2000-06-01

    MRI with hyperpolarized helium-3 ((3)He) provides high-resolution imaging of ventilated airspaces. The first aim of this (3)He-study was to compare observations of localized signal defects in healthy smokers and non-smokers. A second aim was to describe relationships between parameters of lung function, volume of inspired (3)He and signal-to-noise ratio. With Ethics Committee approval and informed consent, 12 healthy volunteers (seven smokers and five non-smokers) were studied. Imaging was performed in a 1.5 T scanner using a two-dimensional FLASH sequence at 30V transmitter amplitude (TR/TE/alpha = 11 ms/4.2 ms/microprocessor-controlled delivery device and imaged during single breath-holds. Images were evaluated visually, and scored using a prospectively defined 'defect-index'. Signal-to-noise ratio of the images were correlated with localization, (3)He volumes and static lung volumes. Due to poor image quality studies of two smokers were not eligible for the evaluation. Smokers differed from non-smokers in total number and size of defects: the 'defect-index' of smokers ranged between 0.8 and 6.0 (median = 1.1), that of non-smokers between 0.1 and 0.8 (median = 0.4). Intraindividually, an anteroposterior gradient of signal-to-noise ratio was apparent. Signal-to-noise ratio correlated with the estimated amount of hyperpolarization administered (r = 0. 77), but not with static lung volumes. We conclude that (3)He MRI is a sensitive measure to detect regional abnormalities in the distribution of ventilation in clinically healthy persons with normal pulmonary function tests.

  4. Electron Bubbles in Superfluid ^3 He-A: Exploring the Quasiparticle-Ion Interaction

    Science.gov (United States)

    Shevtsov, Oleksii; Sauls, J. A.

    2016-11-01

    When an electron is forced into liquid ^3 He, it forms an "electron bubble", a heavy ion with radius, R˜eq 1.5 nm, and mass, M˜eq 100 m_3 , where m_3 is the mass of a ^3 He atom. These negative ions have proven to be powerful local probes of the physical properties of the host quantum fluid, especially the excitation spectra of the superfluid phases. We recently developed a theory for Bogoliubov quasiparticles scattering off electron bubbles embedded in a chiral superfluid that provides a detailed understanding of the spectrum of Weyl Fermions bound to the negative ion, as well as a theory for the forces on moving electron bubbles in superfluid ^3 He-A (Shevtsov and Sauls in Phys Rev B 94:064511, 2016). This theory is shown to provide quantitative agreement with measurements reported by the RIKEN group (Ikegami et al. in Science 341(6141):59, 2013) for the drag force and anomalous Hall effect of moving electron bubbles in superfluid ^3 He-A. In this report, we discuss the sensitivity of the forces on the moving ion to the effective interaction between normal-state quasiparticles and the ion. We consider models for the quasiparticle-ion (QP-ion) interaction, including the hard-sphere potential, constrained random-phase-shifts, and interactions with short-range repulsion and intermediate-range attraction. Our results show that the transverse force responsible for the anomalous Hall effect is particularly sensitive to the structure of the QP-ion potential and that strong short-range repulsion, captured by the hard-sphere potential, provides an accurate model for computing the forces acting on the moving electron bubble in superfluid 3 He-A.

  5. Theory of laser enhancement and suppression of cold reactions: the fermion-boson 6Li+7Li2(variant Planck's over 2pi omega0) 6Li7Li+7Li radiative collision.

    Science.gov (United States)

    Li, Xuan; Parker, Gregory A; Brumer, Paul; Thanopulos, Ioannis; Shapiro, Moshe

    2008-03-28

    We present a nonperturbative time-dependent quantum mechanical theory of the laser catalysis and control of a bifurcating A+BC(variant Planck's over 2pi omega(0))ABC*(v)(variant Planck's over 2pi omega(0) )AB+C reaction, with ABC*(v) denoting an intermediate, electronically excited, complex of ABC in the vth vibrational state. We apply this theory to the low collision energy fermion-boson light-induced exchange reaction, (6)Li((2)S)+(7)Li(2)((3)Sigma(u)(+))(variant Planck's over 2pi omega(0))((6)Li(7)Li(7)Li)*(variant Planck's over 2pi omega(0))(6)Li(7)Li((3)Sigma(+))+(7)Li((2)S). We show that at very low collision energies and energetically narrow (approximately 0.01 cm(-1)) initial reactant wave packets, it is possible to tune the yield of the exchange reaction from 0 to near-unity (yield >or=99%) values. Controllability is somewhat reduced at collisions involving energetically wider (approximately 1 cm(-1)) initial reactant wave packets. At these energetic bandwidths, the radiative reactive control, although still impressive, is limited to the 0%-76% reactive-probabilities range.

  6. Integration of a $^6$LiInSe$_2$ Thermal Neutron Detector into a CubeSat Instrument

    CERN Document Server

    Egner, Joanna C; Burger, Arnold; Stassun, Keivan G; Buliga, Vladimir; Matei, Liviu; Bodnarik, Julia G; Stowe, Ashley C; Prettyman, Thomas H

    2016-01-01

    We present a preliminary design for a novel neutron detection system that is compact, lightweight, and low power consuming, utilizing the CubeSat platform making it suitable for space-based applications. This is made possible using the scintillating crystal lithium indium diselenide ($^6$LiInSe$_2$), the first crystal to include $^6$Li in the crystalline structure, and a silicon avalanche photodiode (Si-APD). The schematics of this instrument are presented as well as the response of the instrument to initial testing under alpha radiation. A principal aim of this work is to demonstrate the feasibility of such a neutron detection system within a CubeSat platform. The entire end-to-end system presented here is 10 cm x 10 cm x 15 cm, weighs 670 grams and requires 5 Volts direct current at 3 Watts.

  7. Astrophysical S-factor for $^6$Li$(p,\\gamma)$$^7$Be in the coupled-channel Gamow shell model

    CERN Document Server

    Dong, G X; Michel, N; Płoszajczak, M

    2015-01-01

    We have applied the Gamow shell model (GSM) in the coupled-channel representation to study the astrophysical $S$-factor for the proton radiative capture reaction of $^6$Li. Reaction channels are built by coupling the proton wave function expanded in different partial waves with the GSM wave functions of the ground state ($1^+$) and the excited states ($3^+_1$, $0^+_1$ and $2^+_1$) of $^6$Li. All relevant $E1$, $M1$, and $E2$ transitions from the initial continuum states in $^7$Be to the final bound states (${3/2}^-_1$ and ${1/2}^-_1$) states are included. It is found that the calculated total astrophysical $S$ factor for this reaction agrees well with the experimental data.

  8. Projectile breakup dynamics for {sup 6}Li+{sup 59}Co: Kinematical analysis of {alpha}-d coincidences

    Energy Technology Data Exchange (ETDEWEB)

    Souza, F.A.; Carlin, N.; Liguori Neto, R.; Siqueira-Mello, C.; Moura, M.M. de; Munhoz, M.G.; Oliveira, R.A.N.; Santo, M.G. del; Suaide, A.A.P.; Szanto, E.M.; Szanto de Toledo, A. [Instituto de Fisica - Universidade de Sao Paulo, Departamento de Fisica Nuclear, Sao Paulo, SP (Brazil); Beck, C. [CNRS-IN2P3 and Universite Louis Pasteur, Institut Pluridisciplinaire Hubert Curien, UMR 7178, Strasbourg (France); Keeley, N. [The Andrzej Soltan Institute for Nuclear Studies, Department of Nuclear Reactions, Warsaw (Poland); Diaz-Torres, A. [University of Surrey, Department of Physics, Faculty of Engineering and Physical Sciences, Guildford (United Kingdom)

    2010-05-15

    A study of the kinematics of the {alpha} -d coincidences in the {sup 6}Li+{sup 59}Co system at a bombarding energy of E{sub lab}=29.6 MeV is presented. With exclusive measurements performed over different angular intervals it is possible to identify the respective contributions of the sequential and direct projectile breakup components. The angular distributions of both breakup components are fairly well described by the Continuum-Discretized Coupled-Channels framework (CDCC). Furthermore, a careful analysis of these processes using a semiclassical approach provides information on both their lifetime and their distance of occurrence with respect to the target. Breakup to the low-lying (near-threshold) continuum is delayed, and happens at large internuclear distances. This suggests that the influence of the projectile breakup on the complete fusion process can be related essentially to the direct breakup to the {sup 6}Li high-lying continuum spectrum. (orig.)

  9. Formation of η{sup '} (958) meson bound states by the {sup 6}Li(γ,d) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Miyatani, M.; Nagahiro, H.; Hirenzaki, S. [Nara Women' s University, Department of Physics, Nara (Japan); Ikeno, N. [Tottori University, Department of Regional Environment, Tottori (Japan)

    2016-07-15

    We have investigated the {sup 6}Li(γ,d) reaction theoretically for the formation of the η{sup '}(958) mesic nucleus close to the recoilless kinematics. We have developed the theoretical formula and reported the quantitative results of the formation spectra for various cases in this article. We have found that the formation cross sections are reduced by the effects of the fragile deuteron form factor. (orig.)

  10. Theoretical study of the α +d →6Li +γ astrophysical capture process in a three-body model

    Science.gov (United States)

    Tursunov, E. M.; Kadyrov, A. S.; Turakulov, S. A.; Bray, I.

    2016-07-01

    The astrophysical capture process α +d →6Li is studied in a three-body model. The initial state is factorized into the deuteron bound state and the (α +d )-scattering state. The final nucleus 6Li (1+) is described as a three-body bound state α +n +p in the hyperspherical Lagrange-mesh method. The contribution of the E 1 -transition operator from the initial isosinglet states to the isotriplet components of the final state is estimated to be negligible. An estimation of the forbidden E 1 transition to the isosinglet components of the final state is comparable with the corresponding results of the two-body model. However, the contribution of the E 2 -transition operator is found to be much smaller than the corresponding estimations of the two-body model. The three-body model perfectly matches the new experimental data of the LUNA Collaboration with the spectroscopic factor of 2.586 estimated from the bound-state wave functions of 6Li and a deuteron.

  11. Unified description of $^6$Li structure and deuterium-$^4$He dynamics with chiral two- and three-nucleon forces

    CERN Document Server

    Hupin, Guillaume; Navrátil, Petr

    2014-01-01

    Prototype for the study of weakly bound projectiles colliding on stable targets, the scattering of deuterium ($d$) on $^4$He ($\\alpha$) is an important milestone in the search for a fundamental understanding of low-energy reactions. At the same time, it is also important for its role in the Big-bang nucleosynthesis of $^6$Li and applications in the characterization of deuterium impurities in materials. We present the first unified {\\em ab initio} study of the $^6$Li ground state and $d$-$^4$He elastic scattering using two- and three-nucleon forces derived within the framework of chiral effective field theory. The six-nucleon bound-state and scattering observables are calculated by means of the no-core shell model with continuum. %and are compared to available experimental data. We analyze the influence of the dynamic polarization of the deuterium and of the chiral three-nucleon force, and examine the role of the continuum degrees of freedom in shaping the low-lying spectrum of $^6$Li. We find that the adopted...

  12. Surface Scattering Effect and the Stripe Order in Films of the Superfluid 3He B Phase

    Science.gov (United States)

    Aoyama, Kazushi

    2016-09-01

    Surface scattering effects in thin films of the superfluid 3He B phase have been theoretically investigated, with an emphasis on the stability of the stripe order with spontaneous broken translational symmetry in the film plane and quasiparticle excitations in this spatially inhomogeneous phase. Based on the Ginzburg-Landau theory in the weak coupling limit, we have shown that the stripe order, which was originally discussed for a film with two specular surfaces, can be stable in a film with one specular and one diffusive surfaces which should correspond to superfluid 3He on a substrate. It is also found by numerically solving the Eilenberger equation that due to the stripe structure, a midgap state distinct from the surface Andreev bound state emerges and its signature is reflected in the local density of states.

  13. Dynamical Behavior of Core 3 He Nuclear Reaction-Diffusion Systems and Sun's Gravitational Field

    Institute of Scientific and Technical Information of China (English)

    DU Jiulin; SHEN Hong

    2005-01-01

    The coupling of the sun's gravitational field with processes of diffusion and convection exerts a significant influence on the dynamical behavior of the core 3He nuclear reaction-diffusion system. Stability analyses of the system are made in this paper by using the theory of nonequilibrium dynamics. It is showed that, in the nuclear reaction regions extending from the center to about 0.38 times of the radius of the sun, the gravitational field enables the core 3He nuclear reaction-diffusion system to become unstable and, after the instability, new states to appear in the system have characteristic of time oscillation. This may change the production rates of both 7Be and 8B neutrinos.

  14. Observation of Intrinsic Magnus Force and Direct Detection of Chirality in Superfluid 3He-A

    Science.gov (United States)

    Ikegami, Hiroki; Tsutsumi, Yasumasa; Kono, Kimitoshi

    2015-04-01

    We report details of the observation of the intrinsic Magnus (IM) force acting on negative and positive ions trapped just below a free surface of the A phase of superfluid 3He (3He-A). From the transport measurements of the ions along the surface, we found that the IM force acts on both the negative and positive ions. We also demonstrate that the transport measurements could distinguish whether the surface is composed of a chiral monodomain or multiple chiral domains. For multiple chiral domains, the current of the ions was found to be irreproducible and unstable, which was reasonably explained by the formation of the chiral domain structure and the dynamics of the chiral domain walls. For chiral monodomains, the appearance ratio of chirality emerging upon cooling through the superfluid transition temperature was found to depend on the direction of the external magnetic field, which implies the existence of an unknown coupling between the chirality and the magnetic field.

  15. Dielectric constant of /sup 3/He near the liquid-vapor critical point

    Energy Technology Data Exchange (ETDEWEB)

    Doiron, T.; Meyer, H.

    1978-03-01

    High-resolution measurements of the static dielectic constant epsilon along the critical isochore are reported for /sup 3/He in the region of the critical point. The experiments were conducted at a frequency of 1000 Hz and the purpose was to observe a divergence of (partialepsilon/partialT)/sub rhoc/ as T/sub c/ is approached from above. No evidence for a critical anomaly was found, the estimated upper bound for its integrated value being deltaepsilon approx. 4 x 10/sup -8/ which is consistent with the theoretical estimations. Hence the recently reported is not observed in /sup 3/He. In the Appendix, some experimental questions arising in such constant-density experiments are discussed.

  16. Study of the pd(dp) -> 3He pi pi reactions close to threshold

    CERN Document Server

    Bellemann, F; Bisplinghoff, J; Bohlscheid, G; Ernst, J; Henrich, C; Hinterberger, F; Ibald, R; Jahn, R; Joosten, R; Kilian, K; Kozela, A; Machner, H; Magiera, A; Munkel, J; von Neumann-Cosel, P; von Rossen, P; Schnitker, H; Scho, K; Smyrski, J; Toelle, R; Wilkin, C

    2016-01-01

    New experimental data on the pd -> 3He pi+ pi- reaction obtained with the COSY-MOMO detector below the three-pion threshold are presented. The reaction was also studied in inverse kinematics with a deuteron beam and the higher counting rates achieved were especially important at low excess energies. The comparison of these data with inclusive pd -> 3He+X rates allowed estimates also to be made of pi0 pi0 production. The results confirm our earlier findings that close to threshold there is no enhancement at low excitation energies in the pi+ pi- system, where the data seem largely suppressed compared to phase space. Possible explanations for this behavior, such as strong p- waves in the pi+pi- -system or the influence of two-step processes, are explored.

  17. Probing the short range spin dependent interactions by polarized {sup 3}He atom beams

    Energy Technology Data Exchange (ETDEWEB)

    Yan, H. [China Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang, Sichuan (China); Indiana University, Center for Exploration of Energy and Matter, Bloomington, IN (United States); Sun, G.A.; Gong, J.; Pang, B.B.; Wang, Y.; Yang, Y.W.; Zhang, J.; Zhang, Y. [China Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang, Sichuan (China)

    2014-10-15

    Experiments using polarized {sup 3}He atom beams to search for short range spin dependent forces are proposed. High intensity, high polarization, small beam size {sup 3}He atom beams have been successfully produced and used in surface science researches. By incorporating background reduction designs as combination shielding by μ-metal and superconductor and double beam paths, the precision of spin rotation angle per unit length could be improved by a factor of ∝ 10{sup 4}. By this precision, in combination with a high density and low magnetic susceptibility sample source mass, and reversing one beam path if necessary, sensitivities on three different types of spin dependent interactions could be improved by as much as ∝ 10{sup 2} to ∝ 10{sup 8} over the current experiments at the millimeter range. (orig.)

  18. Decoupling of first sound from second sound in dilute 3He-superfluid 4He mixtures

    Science.gov (United States)

    Riekki, T. S.; Manninen, M. S.; Tuoriniemi, J. T.

    2016-12-01

    Bulk superfluid helium supports two sound modes: first sound is an ordinary pressure wave, while second sound is a temperature wave, unique to superfluid systems. These sound modes do not usually exist independently, but rather variations in pressure are accompanied by variations in temperature, and vice versa. We studied the coupling between first and second sound in dilute 3He -superfluid 4He mixtures, between 1.6 and 2.2 K, at 3He concentrations ranging from 0% to 11%, under saturated vapor pressure, using a quartz tuning fork oscillator. Second sound coupled to first sound can create anomalies in the resonance response of the fork, which disappear only at very specific temperatures and concentrations, where two terms governing the coupling cancel each other, and second sound and first sound become decoupled.

  19. High-3He plume origin and temporal-spatial evolution of the Siberian flood basalts

    Science.gov (United States)

    Basu, A.R.; Poreda, R.J.; Renne, P.R.; Teichmann, F.; Vasiliev, Y.R.; Sobolev, N.V.; Turrin, B.D.

    1995-01-01

    An olivine nephelinite from the lower part of a thick alkalic ultrabasic and mafic sequence of volcanic rocks of the northeastern part of the Siberian flood basalt province (SFBP) yielded a 40ArX39Ar plateau age of 253.3 ?? 2.6 million years, distinctly older than the main tholeiitic pulse of the SFBP at 250.0 million years. Olivine phenocrysts of this rock showed 3He/4He ratios up to 12.7 times the atmospheric ratio; these values suggest a lower mantle plume origin. The neodymium and strontium isotopes, rare earth element concentration patterns, and cerium/lead ratios of the associated rocks were also consistent with their derivation from a near-cnondritic, primitive plume. Geochemical data from the 250-million-year-old volcanic rocks higher up in the sequence indicate interaction of this high-3He SFBP plume with a suboceanic-type upper mantle beneath Siberia.

  20. Particle transport in 3 He-rich events: wave-particle interactions and particle anisotropy measurements

    Science.gov (United States)

    Tsurutani, B. T.; Zhang, L. D.; Mason, G. L.; Lakhina, G. S.; Hada, T.; Arballo, J. K.; Zwickl, R. D.

    2002-04-01

    Energetic particles and MHD waves are studied using simultaneous ISEE-3 data to investigate particle propagation and scattering between the source near the Sun and 1 AU. 3 He-rich events are of particular interest because they are typically low intensity "scatter-free" events. The largest solar proton events are of interest because they have been postulated to generate their own waves through beam instabilities. For 3 He-rich events, simultaneous interplanetary magnetic spectra are measured. The intensity of the interplanetary "fossil" turbulence through which the particles have traversed is found to be at the "quiet" to "intermediate" level of IMF activity. Pitch angle scattering rates and the corresponding particle mean free paths l

  1. First results from Tyrex, the new polarized-{sup 3}He filling station at ILL

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, K.H. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France)]. E-mail: andersen@ill.fr; Chung, R. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Guillard, V. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Humblot, H. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Jullien, D. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Lelievre-Berna, E. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Petoukhov, A. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Tasset, F. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France)

    2005-02-15

    A new filling station for nuclear polarisation of {sup 3}He gas has been constructed at the ILL, Grenoble. The 'Tyrex' machine uses metastability-exchange optical pumping for polarising the {sup 3}He gas at about 1 mbar pressure. The gas is then compressed up to several bars via a hydraulic titanium-alloy piston compressor. The machine can provide about 1.5 bar-l/h of polarised gas--an order-of-magnitude increase over the first filling station installed at the ILL in 1996. The compressed, polarised gas is used for polarising neutron beams for condensed-matter and fundamental physics experiments. First results are presented and examples of implementations on existing neutron instruments at ILL are described.

  2. Laboratory tests of a modified {sup 3}He detector for use with startup instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Qian, T.; Tonner, P.; Keller, N. [Atomic Eerngy of Canada Limited, Chalk River, ON (Canada)] [and others

    1997-07-01

    Boron trifluoride (BF{sub 3}) detectors are currently used in all CANDU stations as startup instrumentation (SUI) detectors for monitoring neutron flux during extended outages and startups. Experience at some CANDU stations has shown that some models of BF{sub 3} detectors degrade quickly, even in moderate neutron and gamma fields. Degradation and life expectancy tests for five models of BF{sub 3} detectors from different manufacturers were performed at Chalk River Laboratories (CRL) to investigate the problem. The test results reveal that most BF{sub 3} detectors have low neutron and gamma durability, and some exhibit an undesirable time-dependent degradation followed by recovery. As a result of this finding, other detector options including a modified helium ({sup 3}He) detector described herein were investigated. Modified {sup 3}He detectors were procured from an established supplier and were found to perform without degradation in neutron and gamma fields. (author)

  3. Neutron Polarization Measurements with a 3He Spin Filter for the NPDGamma Experiment

    Science.gov (United States)

    Musgrave, Matthew

    2012-10-01

    The Fundamental Neutron Physics Beamline (FNPB) at the Spallation Neutron Source (SNS) provides a pulsed beam of polarized cold neutrons for the NPDGamma experiment which intends to measure the parity violating asymmetry in the emitted gamma rays from the capture of polarized neutrons on protons in a para-hydrogen target. The neutrons are polarized by a multi-channel super mirror polarizer, and the polarization of each neutron pulse can be flipped with an RF spin rotator. The accuracy of the NPDGamma experiment and various commissioning experiments is dependent on the polarization of the neutron beam and the efficiency of the RF spin rotator. These parameters are measured with a polarized 3He spin filter at multiple points in the beam cross section and with multiple 3He polarizations. The measured neutron polarization is compared to a McStas model to validate our results and our beam averaging technique. The analysis methods, background effects, and results will be discussed.

  4. Fast-Neutron Spectrometry Using a 3He Ionization Chamber and Digital Pulse Shape Analysis

    Energy Technology Data Exchange (ETDEWEB)

    D. L. Chichester; J. T. Johnson; E. H. Seabury

    2010-05-01

    Digital pulse shape analysis (dPSA) has been used with a Cuttler-Shalev type 3He proportional counter to measure the fast neutron spectra of bare 252Cf and 241AmBe neutron sources. Measurements have also been made to determine the attenuated fast neutron spectra of 252Cf shielded by several materials including water, graphite, liquid nitrogen, magnesium, and tungsten. Rise-time dPSA has been employed using the common rise-time approach for analyzing n +3He ? 1H + 3H ionization events and a new approach has been developed to improve the fidelity of these measurements. Simulations have been performed for the different experimental arrangements and are compared, demonstrating general agreement between the dPSA processed fast neutron spectra and predictions.

  5. Posture-Dependent Human 3He Lung Imaging in an Open Access MRI System: Initial Results

    CERN Document Server

    Tsai, L L; Li, C -H; Rosen, M S; Patz, S; Walsworth, R L

    2007-01-01

    The human lung and its functions are extremely sensitive to orientation and posture, and debate continues as to the role of gravity and the surrounding anatomy in determining lung function and heterogeneity of perfusion and ventilation. However, study of these effects is difficult. The conventional high-field magnets used for most hyperpolarized 3He MRI of the human lung, and most other common radiological imaging modalities including PET and CT, restrict subjects to lying horizontally, minimizing most gravitational effects. In this paper, we briefly review the motivation for posture-dependent studies of human lung function, and present initial imaging results of human lungs in the supine and vertical body orientations using inhaled hyperpolarized 3He gas and an open-access MRI instrument. The open geometry of this MRI system features a "walk-in" capability that permits subjects to be imaged in vertical and horizontal positions, and potentially allows for complete rotation of the orientation of the imaging su...

  6. [sup 3]He neutron detector performance in mixed neutron gamma environments

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, N. H. (Nathan H.); Beddingfield, D. H. (David H.)

    2002-01-01

    A test program of the performance of 3He neutron proportional detectors with varying gas pressures, and their response to lligh level gamma-ray exposure in a mixed neutrodgamma environment, ha$ been performed Our intent was to identie the optimal gas pressure to reduce the gamma-ray sensitivity of these detectors. These detectors were manufxtured using materials to minimize their gamma response. Earlier work focused on 3He fill pressures of four atmospheres and above, whereas the present work focuses on a wider range of pressures. Tests have shown that reducing the .filling pressure will M e r increase the gamma-ray dose range in which the detectors can be operated.

  7. A Light-Front approach to the $^3$He spectral function

    CERN Document Server

    Scopetta, Sergio; Kaptari, Leonid; Pace, Emanuele; Rinaldi, Matteo; Salmè, Giovanni

    2014-01-01

    The analysis of semi-inclusive deep inelastic electron scattering off polarized $^3$He at finite momentum transfers, aimed at the extraction of the quark transverse-momentum distributions in the neutron, requires the use of a distorted spin-dependent spectral function for $^3$He, which takes care of the final state interaction effects. This quantity is introduced in the non-relativistic case, and its generalization in a Poincar\\'e covariant framework, in plane wave impulse approximation for the moment being, is outlined. Studying the light-front spin-dependent spectral function for a J=1/2 system, such as the nucleon, it is found that, within the light-front dynamics with a fixed number of constituents and in the valence approximation, only three of the six leading twist T-even transverse-momentum distributions are independent.

  8. Nuclear structure corrections for μ4He+ and μ3He+ spectroscopy

    Science.gov (United States)

    Nevo Dinur, Nir; Ji, Chen; Hernandez, Oscar; Bacca, Sonia; Barnea, Nir

    2016-09-01

    The proton charge radius was recently determined from muonic hydrogen spectroscopy with tenfold improved precision but 7 . 9 σ disagreement with the accepted value, leading to the ``proton radius puzzle''. To further investigate, and to obtain precise radii, these measurements were repeated in μ4He+ and μ3He+. This may also shed light on the discrepancy between isotope-shift measurements of the 4He -3He radius difference. However, the precision of radii determined from the muonic experiments is limited by the uncertainties in the nuclear structure corrections. We present first ab-initio calculations of these corrections that reduced the uncertainties from 20 % to the few percent goal. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada. This work was supported in parts by the Natural Sciences and Engineering Research Council (Grant Number SAPIN-2015-00031).

  9. Elastic p-3He and n-3H scattering with two- and three-body forces

    CERN Document Server

    Pfitzinger, B; Hale, G M

    2000-01-01

    We report on a microscopic calculation of n-3H and p-3He scattering employing the Argonne v_{18} and v_8' nucleon-nucleon potentials with and without additional three-nucleon force. An R-matrix analysis of the p-3He and n-3H scattering data is presented. Comparisons are made for the phase shifts and a selection of measurements in both scattering systems. Differences between our calculation and the R-matrix results or the experimental data can be attributed to only two partial waves (3P0 and 3P2). We find the effect of the Urbana IX and the Texas-Los Alamos three-nucleon forces on the phase shifts to be negligible.

  10. JLab Measurements of the 3He Form Factors at Large Momentum Transfers

    CERN Document Server

    Camsonne, A; Olson, M; Acha, A; Allada, K; Anderson, B D; Arrington, J; Baldwin, A; Chen, J -P; Choi, S; Chudakov, E; Cisbani, E; Craver, B; Decowski, P; Dutta, C; Folts, E; Frullani, S; Garibaldi, F; Gilman, R; Gomez, J; Hahn, B; Hansen, J -O; Higinbotham, D W; Holmstrom, T; Huang, J; Iodice, M; Jiang, X; Kelleher, A; Khrosinkova, E; Kievsky, A; Kuchina, E; Kumbartzki, G; Lee, B; LeRose, J J; Lindgren, R A; Lott, G; Lu, H; Marcucci, L E; Margaziotis, D J; Markowitz, P; Marrone, S; Meekins, D; Meziani, Z -E; Michaels, R; Moffit, B; Norum, B; Petratos, G G; Puckett, A; Qian, X; Rondon, O; Saha, A; Sawatzky, B; Segal, J; Shabestari, M; Shahinyan, A; Solvignon, P; Sparveris, N; Subedi, R R; Suleiman, R; Sulkosky, V; Urciuoli, G M; Viviani, M; Wang, Y; Wojtsekhowski, B B; Yan, X; Yao, H; Zhang, W -M; Zheng, X; Zhu, L

    2016-01-01

    The charge and magnetic form factors, FC and FM, of 3He have been extracted in the kinematic range 25 fm-2 < Q2 < 61 fm-2 from elastic electron scattering by detecting 3He recoil nuclei and electrons in coincidence with the High Resolution Spectrometers of the Hall A Facility at Jefferson Lab. The measurements are indicative of a second diffraction minimum for the magnetic form factor, which was predicted in the Q2 range of this experiment, and of a continuing diffractive structure for the charge form factor. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the three-body nuclear problem.

  11. Far-ultraviolet signatures of the 3He(n,tp) reaction in noble gas mixtures

    CERN Document Server

    Hughes, Patrick P; Thompson, Alan K; Vest, Robert E; Clark, Charles W

    2010-01-01

    Previous work showed that the 3He(n,tp) reaction in a cell of 3He at atmospheric pressure generated tens of far-ultraviolet photons per reacted neutron. Here we report amplification of that signal by factors of 1000 and more when noble gases are added to the cell. Calibrated filter-detector measurements show that this large signal is due to noble-gas excimer emissions, and that the nuclear reaction energy is converted to far-ultraviolet radiation with efficiencies of up to 30%. The results have been placed on an absolute scale through calibrations at the NIST SURF III synchrotron. They suggest possibilities for high-efficiency neutron detectors as an alternative to existing proportional counters.

  12. Apatite 4He/3He and (U-Th)/He evidence for an ancient Grand Canyon.

    Science.gov (United States)

    Flowers, R M; Farley, K A

    2012-12-21

    The Grand Canyon is one of the most dramatic features on Earth, yet when and why it was carved have been controversial topics for more than 150 years. Here, we present apatite (4)He/(3)He thermochronometry data from the Grand Canyon basement that tightly constrain the near-surface cooling history associated with canyon incision. (4)He/(3)He spectra for eastern Grand Canyon apatites of differing He date, radiation damage, and U-Th zonation yield a self-consistent cooling history that substantially validates the He diffusion kinetic model applied here. Similar data for the western Grand Canyon provide evidence that it was excavated to within a few hundred meters of modern depths by ~70 million years ago (Ma), in contrast to the conventional model in which the entire canyon was carved since 5 to 6 Ma.

  13. A Density Functional for Liquid 3He Based on the Aziz Potential

    Science.gov (United States)

    Barranco, M.; Hernández, E. S.; Mayol, R.; Navarro, J.; Pi, M.; Szybisz, L.

    2006-09-01

    We propose a new class of density functionals for liquid 3He based on the Aziz helium-helium interaction screened at short distances by the microscopically calculated two-body distribution function g(r). Our aim is to reduce to a minumum the unavoidable phenomenological ingredients inherent to any density functional approach. Results for the homogeneous liquid and droplets are presented and discussed.

  14. In vivo lung morphometry with hyperpolarized 3He diffusion MRI: theoretical background.

    Science.gov (United States)

    Sukstanskii, A L; Yablonskiy, D A

    2008-02-01

    MRI-based study of (3)He gas diffusion in lungs may provide important information on lung microstructure. Lung acinar airways can be described in terms of cylinders covered with alveolar sleeve [Haefeli-Bleuer, Weibel, Anat. Rec. 220 (1988) 401]. For relatively short diffusion times (on the order of a few ms) this geometry allows description of the (3)He diffusion attenuated MR signal in lungs in terms of two diffusion coefficients-longitudinal (D(L)) and transverse (D(T)) with respect to the individual acinar airway axis [Yablonskiy et al., PNAS 99 (2002) 3111]. In this paper, empirical relationships between D(L) and D(T) and the geometrical parameters of airways and alveoli are found by means of computer Monte Carlo simulations. The effects of non-Gaussian signal behavior (dependence of D(L) and D(T) on b-value) are also taken into account. The results obtained are quantitatively valid in the physiologically important range of airway parameters characteristic of healthy lungs and lungs with mild emphysema. In lungs with advanced emphysema, the results provide only "apparent" characteristics but still could potentially be used to evaluate emphysema progression. This creates a basis for in vivo lung morphometry-evaluation of the geometrical parameters of acinar airways from hyperpolarized (3)He diffusion MRI, despite the airways being too small to be resolved by direct imaging. These results also predict a rather substantial dependence of (3)He ADC on the experimentally-controllable diffusion time, Delta. If Delta is decreased from 3 ms to 1 ms, the ADC in normal human lungs may increase by almost 50%. This effect should be taken into account when comparing experimental data obtained with different pulse sequences.

  15. Thermal hysteresis of the thermal conductivity in isotopically impure bcc 3He

    Science.gov (United States)

    Greenberg, A. S.; Armstrong, G.

    1980-11-01

    We have measured the thermal conductivity of bcc 3He containing 10 and 500 ppm 4He for temperatures below the isotopic phase separation. We find the conductivity measured during cooling can be significantly greater, as much as an order of magnitude, than upon warming. This hysteresis depends strongly on the molar volume and 4He concentration. We interpret our results in terms of phonon scattering from the boundary of solid 4He clusters formed by quantum diffusion and nucleated by crystalline faults.

  16. Primary populations of metastable antiprotonic $^{4}He$ and $^{3}He$ atoms

    CERN Document Server

    Hori, Masaki; Hayano, R S; Ishikawa, T; Sakuguchi, J; Tasaki, T; Widmann, E; Yamaguchi, H; Torii, H A; Juhász, B; Horváth, D; Yamazaki, T

    2002-01-01

    Initial population distributions of metastable antiprotonic **4He and **3He atoms over principal and angular momentum quantum numbers were investigated using laser spectroscopy. The total fractions of antiprotons captured into the metastable states of the atoms were deduced. Cascade calculations were performed using the measure populations to reproduce the delayed annihilation time spectrum. Results showed agreement between the simulated and measured spectra. (Edited abstract) 30 Refs.

  17. Testing on novel neutron detectors as alternative to {sup 3}He for security applications

    Energy Technology Data Exchange (ETDEWEB)

    Peerani, Paolo, E-mail: paolo.peerani@jrc.ec.europa.eu [European Commission, Joint Research Centre, ITU, Ispra, VA (Italy); Tomanin, Alice [European Commission, Joint Research Centre, ITU, Ispra, VA (Italy); University of Gent, Faculteit Toegepaste Wetenschappen, Gent (Belgium); Pozzi, Sara; Dolan, Jennifer; Miller, Eric; Flaska, Marek [University of Michigan, Department of Nuclear Engineering and Radiological Sciences, Ann Arbor, MI (United States); Battaglieri, Marco; De Vita, Raffaella [Istituto Nazionale di Fisica Nucleare, Sezione di Genova, Genova (Italy); Ficini, Luisa [Istituto Nazionale di Fisica Nucleare, Sezione di Genova, Genova (Italy); Universita di Genova, Dipartimento di Fisica, Genova (Italy); Ottonello, Giacomo [Istituto Nazionale di Fisica Nucleare, Sezione di Genova, Genova (Italy); Ricco, Giovanni [Istituto Nazionale di Fisica Nucleare, Sezione di Genova, Genova (Italy); Universita di Genova, Dipartimento di Fisica, Genova (Italy); Dermody, Geraint; Giles, Calvin [Symetrica Limited, Southampton (United Kingdom)

    2012-12-22

    Detection of illicit trafficking of nuclear material relies on the detection of the radiation emitted. In the case of plutonium, one of the characteristic signatures derives from neutron emission. For this reason, neutron detectors cover an important role in detection systems. Most current neutron detection systems used for nuclear security are based on the {sup 3}He technology. Unfortunately, in the last few years the market of {sup 3}He has encountered huge problems in matching the supply and the demand. The need has grown significantly due to the increasing demand of instrumentation for security. This has caused an exponential increase of the price from one side and on the other side a serious strategic problem of resources. In order to guarantee the availability of detection systems for nuclear security, it is necessary to develop alternative detection systems based on technologies different from {sup 3}He. Many research projects have been devoted for the development of novel neutron detectors both by research organisations and by industries. Scientists from the PERLA laboratory of the Joint Research Centre (JRC) in Ispra, Italy, and their collaborators have tested several of these novel concepts in the last couple of years. This paper describes the detector systems tested at JRC and preliminary results on detectors that can be considered as promising alternatives to {sup 3}He. -- Highlights: Black-Right-Pointing-Pointer The paper tackles the problem of lack of He-3 supply. Black-Right-Pointing-Pointer This impacts neutron detection for security applications. Black-Right-Pointing-Pointer The aim is to test innovative/alternative solutions for neutron detectors. Black-Right-Pointing-Pointer Encouraging results obtained with organic and Li-based scintillators.

  18. Magnetisation distribution measurements from powders using a {sup 3}He spin filter: a test experiment

    Energy Technology Data Exchange (ETDEWEB)

    Wills, A.S. [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom) and Davy Faraday Research Laboratory, Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS (United Kingdom)]. E-mail: a.s.wills@ucl.ac.uk; Lelievre-Berna, E. [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France); Tasset, F. [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France); Schweizer, J. [Departement de Recherche Fondamentale sur la Matiere Condensee, SPSMS, CEA Grenoble, 38054 Grenoble (France); Ballou, R. [Laboratoire de Magnetisme Louis Neel - CNRS, BP 166, 38042 Grenoble Cedex 9 (France)

    2005-02-15

    Magnetisation distribution maps deduced from the measurement of polarization dependent cross-sections have provided information that has been key to our understanding of the detailed electronic configurations and mechanisms of superconductors, colossal magnetoresistance and molecular magnets. Presently, the absence of any installation on a powder instrument limits its application largely to single crystals. This article details a test experiment carried out using polarized {sup 3}He spin filters on a powder diffractometer together with the technical background and data analysis considerations.

  19. Compact magnetostatic cavity for polarised {sup 3}He neutron spin filter cells

    Energy Technology Data Exchange (ETDEWEB)

    Petoukhov, A.K. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France)]. E-mail: petukhov@ill.fr; Guillard, V. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Andersen, K.H. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Bourgeat-Lami, E. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Chung, R. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Humblot, H. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Jullien, D. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Lelievre-Berna, E. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Soldner, T. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Tasset, F. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France); Thomas, M. [Institute Laue-Langevin, 6, rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9 (France)

    2006-05-10

    We present a concept for a compact magnetostatic cavity called a 'Magic box' that provides a very homogeneous magnetic environment for a polarised {sup 3}He neutron spin-filter cell in the presence of moderate magnetic stray fields. Based on this concept different systems have been built and tested. The concept is ideal for the transport or hosting of a spin-filter on a neutron beam-line.

  20. Search for a bound trineutron with the 3He(π-pgr;+)nnn reaction

    Science.gov (United States)

    Gräter, J.; Amaudruz, P. A.; Bilger, R.; Camerini, P.; Clark, J.; Clement, H.; Friedman, E.; Felawka, L.; Filippov, S. N.; Friagiacomo, E.; Gavrilov, Y. K.; Gibson, E.; Grion, N.; Hofman, G. J.; Jamieson, B.; Karavicheva, T. L.; Kermanipresent Address: Sonigistix Corporation, Richmond, B. C., Canada V7A-5E3-->, M.; Mathie, E. L.; Meier, R.; Moloney, G.; Ottewell, D.; Pätzold, J.; Patarakin, O.; Raywood, K.; Rui, R.; Schepkin, M.; Sevior, M. E.; Smith, G. R.; Staudenmaier, H.; Tacik, R.; Tagliente, G.; Wagner, G. J.; Yeomans, M.

    1999-01-01

    A search for the production of a bound trineutron state has been performed using the reaction 3He(π-,π+)nnn at incident pion energies of 65, 75, and 120 MeV. No evidence for the existence of the 3n was found, and an upper limit for the production cross section of approximately 30 nb/sr (2σ confidence level) was obtained.

  1. Experiment E89-044 on the Quasielastic 3He(e,e'p) Reaction at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    E. Penel-Nottaris

    2004-07-07

    The Jefferson Lab Hall A E89-044 experiment has measured the 3He(e,e'p) reaction cross-sections. The extraction of the longitudinal and transverse response functions for the two-body break-up 3He(e,e'p)d reaction in parallel kinematics allows the study of the bound proton electromagnetic properties inside the 3He nucleus and the involved nuclear mechanisms beyond plane wave approximations.

  2. Precision measurement of thermal neutron beam densities using a 3He proportional counter

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage; Bahnsen, A.; Brown, W.K.

    1967-01-01

    A new method, based on the 3He(n, p)T reaction, has been developed for the accurate determination of thermal neutron beam densities. Several comparisons were made with the conventional Au-foil activation method, and agreement was obtained between the two methods within an experimental uncertainty...... of ±0.4%. Fundamental advantages of the method include the 1ν dependence of the 3He(n, p)T cross section up to 1 keV, and the assurance of homogeneity even for very small macroscopic cross sections, because of the gaseous detector material. Although the method requires a relatively clean neutron beam......, it can be used over a wide range of neutron densities and, in particular, is capable of measuring extremely weak beams. A detector has been constructed with a well-defined efficiency and which is able to accept beams of diameters up to 10 cm. The 3He counter method is proposed as a precision standard...

  3. A New 3He-Target Design for Compton Scattering Experiment

    Science.gov (United States)

    Mahalchick, S.; Gao, H.; Laskaris, G.; Weir, W.; Ye, Q.; Ye, Q. J.

    2011-10-01

    The neutron spin polarizabilities describe the stiffness of the neutron spin to external electric and magnetic fields. A double-polarized elastic Compton Scattering experiment will try to determine the neutron spin polarizabilities using a new polarized 3He target and the circularly polarized γ-beam of HI γS facility at the Duke Free Electron Laser Laboratory (DFELL). To polarize the 3He target, a newly constructed solenoid is being used which can provide a very uniform magnetic field around the target area and allows to place High Intensity Gamma Source NaI Detector Arrays (HINDA) closer to the target. The ideal target polarization is 40-60% and will be measured using the nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) techniques. A prototype of the polarized 3He target is being constructed in the Medium Energy Physics Group laboratories at Duke and is currently being tested. The experiment is expected to take place in 2013 after the DFELL upgrade. I will be presenting details of the construction process, including design specifications and data from the magnetic field mapping, as well as preliminary target polarization results. This work is supported by the US Department of Energy, under contract number DE-FG02-03ER41231, and by the National Science Foundation, grant number NSF-PHY-08-51813.

  4. Hyperpolarised sup 3 He gas production for magnetic resonance imaging of the human air ways

    CERN Document Server

    Fichele, S

    2002-01-01

    This thesis describes the experimental techniques, and methods employed in hyperpolarised sup 3 He gas production and magnetic resonance imaging of the human air-ways, using spin-echo sequences and MR tagging techniques. An in-house polariser utilising the metastability optical pumping technique was constructed. The main results of this work are concerned with engineering difficulties involved in compressing HP sup 3 He and a large proportion of this PhD thesis details the design, construction, and performance of an in-house built peristaltic compressor. In preliminary imaging experiments using RARE, high signal to noise projection images of the lungs were acquired using less than 0.5 cm sup 3 (STP) of purely polarised HP gas. Later, increased HP gas quantities (typically 10 cm sup 3) were obtained by employing the peristaltic compressor. Consequently we could acquire 10 mm thick slices spanning the entire lung following a single sup 3 He gas bolus administration. Finally, the first results using MR tagging t...

  5. A 3 He-129 Xe co-magnetometer with 87 Rb magnetometry

    Science.gov (United States)

    Limes, Mark; Sheng, Dong; Romalis, Mike

    2016-05-01

    We report progress on a 3 He-129 Xe co-magnetometer detected with a 87 Rb magnetometer. The noble-gas co-magnetometer is insensitive to any long-term bias field drifts, but the presence of hot Rb can cause instability in the ratio of 3 He-129 Xe precession frequencies. We use a sequence of Rb π pulses to suppress the instability due to Rb-noble gas interactions by a factor of 104 along all three spatial axes. For detection, our 87 Rb magnetometer operates using single-axis 87 Rb π pulses with σ+ /σ- pumping-this technique decouples the 87 Rb magnetometer from bias fields, and allows for SERF operation. We are presently investigating systematic effects due to combinations of several imperfections, such as longitudinal noble gas polarization, imperfect 87 Rb π pulses, and 87 Rb pump light shifts. Thus far, our 87 Rb magnetometer has a sensitivity of 40 fT/√{Hz}, and our 3 He-129 Xe co-magnetometer has achieved a single-shot precession frequency ratio error of 20 nHz and a long-term bias drift of 8 nHz at 7 h. We are developing the co-magnetometer for use as an NMR gyro, and to search for possible spin-gravity interactions. Supported by DARPA and NSF.

  6. Transfer of polarized 3He ions in the AtR beam transfer line

    Energy Technology Data Exchange (ETDEWEB)

    Tsoupas N.; MacKay, W.W.; Meot, F.; Roser, T.; Trbojevic, D.

    2012-05-20

    In addition to collisions of electrons with various unpolarized ion species as well as polarized protons, the proposed electron-hadron collider (eRHIC) will facilitate the collisions of electrons with polarized {sup 3}He ions. The AGS is the last acceleration stage, before injection into one of the RHIC's collider ring for final acceleration. The AtR (AGS to RHIC) transfer line will be utilized to transport the polarized {sup 3}He ions from AGS into one of the RHIC's collider rings. Some of the peculiarities of the AtR line's layout (simultaneous horizontal and vertical bends) may degrade the matching of the stable spin direction of the AtR line with that of RHIC's. In this paper we discuss possible simple modifications of the AtR line to accomplish a perfect matching of the stable spin direction of the injected {sup 3}He beam with the stable spin direction at the injection point of RHIC.

  7. Development of 10B-Based 3He Replacement Neutron Detectors

    Science.gov (United States)

    King, Michael J.; Gozani, Tsahi; Hilliard, Donald B.

    2011-12-01

    Radiation portal monitors (RPM) are currently deployed at United States border crossings to passively inspect vehicles and persons for any emission of neutrons and/or gamma rays, which may indicate the presence of unshielded nuclear materials. The RPM module contains an organic scintillator with 3He proportional counters to detect gamma rays and thermalized neutrons, respectively. The supply of 3He is rapidly dwindling, requiring alternative detectors to provide the same function and performance. Our alternative approach is one consisting of a thinly-coated 10B flat-panel ionization chamber neutron detector that can be deployed as a direct drop-in replacement for current RPM 3He detectors. The uniqueness of our approach in providing a large-area detector is in the simplicity of construction, scalability of the unit cell detector, ease of adaptability to a variety of applications and low cost. Currently, Rapiscan Laboratories and Helicon Thin Film Systems have designed and developed an operational 100 cm2 multi-layer prototype 10BB-based ionization chamber.

  8. Linking Ventilation Heterogeneity Quantified via Hyperpolarized 3He MRI to Dynamic Lung Mechanics and Airway Hyperresponsiveness.

    Science.gov (United States)

    Lui, Justin K; Parameswaran, Harikrishnan; Albert, Mitchell S; Lutchen, Kenneth R

    2015-01-01

    Advancements in hyperpolarized helium-3 MRI (HP 3He-MRI) have introduced the ability to render and quantify ventilation patterns throughout the anatomic regions of the lung. The goal of this study was to establish how ventilation heterogeneity relates to the dynamic changes in mechanical lung function and airway hyperresponsiveness in asthmatic subjects. In four healthy and nine mild-to-moderate asthmatic subjects, we measured dynamic lung resistance and lung elastance from 0.1 to 8 Hz via a broadband ventilation waveform technique. We quantified ventilation heterogeneity using a recently developed coefficient of variation method from HP 3He-MRI imaging. Dynamic lung mechanics and imaging were performed at baseline, post-challenge, and after a series of five deep inspirations. AHR was measured via the concentration of agonist that elicits a 20% decrease in the subject's forced expiratory volume in one second compared to baseline (PC20) dose. The ventilation coefficient of variation was correlated to low-frequency lung resistance (R = 0.647, P ventilation heterogeneity. Also, the degree of AHR appears to be dependent on the degree to which baseline airway constriction creates baseline ventilation heterogeneity. HP 3He-MRI imaging may be a powerful predictor of the degree of AHR and in tracking the efficacy of therapy.

  9. A microscopic cluster model study of $^3$He+$p$ scatterings

    CERN Document Server

    Arai, K; Suzuki, Y

    2008-01-01

    We calculate $^3$He+$p$ scattering phase shifts in two different microscopic cluster models, Model T and Model C, in order to show the effects of tensor force as well as $D$-wave components in the cluster wave function. Model T employs a realistic nucleon-nucleon potential and includes the $D$-wave, whereas Model C employs an effective potential in which the tensor-force effect is considered to be renormalized into the central force and includes only the $S$-wave for the cluster intrinsic motion. The $S$- and $P$-wave elastic scattering phase shifts are obtained in the \\{$^3$He+$p$\\}+\\{$d$ + 2$p$\\} coupled-channels calculation. In Model T, the $d$ + 2$p$ channel plays a significant role in producing the $P$-wave resonant phase shifts but hardly affects the $S$-wave non-resonant phase shifts. In Model C, however, the effect of the $d$ + 2$p$ channel is suppressed in both of the $S$- and $P$-wave phase shifts, suggesting that it is renormalized mostly as the $^3$He(1/2$^+$)+$p$ channel in the resonance region.

  10. First measurement of unpolarized SIDIS cross section and cross section ratios from a $^3$He target

    CERN Document Server

    Yan, X; Aniol, K; Annand, J R M; Averett, T; Benmokhtar, F; Bertozzi, W; Bradshaw, P C; Bosted, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J -P; Chen, W; Chirapatpimol, K; Chudakov, E; Cisbani, E; Cornejo, J C; Cusanno, F; Dalton, M M; Deconinck, W; de Jager, C W; De Leo, R; Deng, X; Deur, A; Ding, H; Dolph, P A M; Dutta, C; Dutta, D; Fassi, L El; Frullani, S; Gao, H; Garibaldi, F; Gaskell, D; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Guo, L; Hamilton, D; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, J; Huang, M; Ibrahim, H F; Iodice, M; Jiang, X; Jin, G; Jones, M K; Katich, J; Kelleher, A; Kim, W; Kolarkar, A; Korsch, W; LeRose, J J; Li, X; Li, Y; Lindgren, R; Liu, T; Liyanage, N; Long, E; Lu, H -J; Margaziotis, D J; Markowitz, P; Marrone, S; McNulty, D; Meziani, Z -E; Michaels, R; Moffit, B; Camacho, C Munoz; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Oh, Y; Osipenko, M; Parno, D; Peng, J -C; Phillips, S K; Posik, M; Puckett, A J R; Qian, X; Qiang, Y; Rakhman, A; Ransome, R; Riordan, S; Saha, A; Sawatzky, B; Schulte, E; Shahinyan, A; Shabestari, M H; Sirca, S; Stepanyan, S; Subedi, R; Sulkosky, V; Tang, L -G; Tobias, W A; Urciuoli, G M; Vilardi, I; Wang, K; Wojtsekhowski, B; Wang, Y; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y; Zhang, Y -W; Zhao, B; Zhao, Y X; Zheng, X; Zhu, L; Zhu, X; Zong, X

    2016-01-01

    The unpolarized semi-inclusive deep-inelastic scattering (SIDIS) differential cross sections in $^3$He($e,e^{\\prime}\\pi^{\\pm}$)$X$ have been measured for the first time in Jefferson Lab experiment E06-010 performed with a $5.9\\,$GeV $e^-$ beam on a $^3$He target. The experiment focuses on the valence quark region, covering a kinematic range $0.12 < x_{bj} < 0.45$, $1 < Q^2 < 4 \\, \\textrm{(GeV/c)}^2$, $0.45 < z_{h} < 0.65$, and $0.05 < P_t < 0.55 \\, \\textrm{GeV/c}$. The extracted SIDIS differential cross sections of $\\pi^{\\pm}$ production are compared with existing phenomenological models while the $^3$He nucleus approximated as two protons and one neutron in a plane wave picture, in multi-dimensional bins. Within the experimental uncertainties, the azimuthal modulations of the cross sections are found to be consistent with zero.

  11. Phase transitions in quantum crystals : on growth of magnetically ordered 3He and a search for supersolid 4He

    NARCIS (Netherlands)

    Bueno, Juan

    2007-01-01

    Due to its rich magnetic phase diagram and its superfluidity, 3He is a very interesting system if magnetic effects on the crystal growth mechanisms want to be studied. Solid 3He orders magnetically into the U2D2 phase (an antiferromagnetic phase with two planes of spins pointing up and two planes o

  12. Precision Measurement of the Spin-dependent Asymmetry in the Threshold Region of Quasielastic 3He

    Energy Technology Data Exchange (ETDEWEB)

    Feng Xiong

    2002-09-01

    The first precision measurement of the spin-dependent asymmetry in the threshold region of polarized {sup 3}He(polarized e, e') was carried out in Hall A at the Jefferson Laboratory, using a longitudinally polarized continuous electron beam incident on a high-pressure polarized {sup 3}He gas target. The polarized electron beam was generated by illuminating a strained GaAs cathode with high intensity circularly polarized laser light, and an average beam polarization of about 70% was achieved. The {sup 3}He target was polarized based on the principle of spin-exchange optical pumpint and the average target polarization was about 30%. The scattered electrons were detected in the two Hall A high resolution spectrometers, HRSe and HRSh. The data from HRSh were used for this analysis and covered both the elastic peak and the threshold region. Two kinematic points were measured in the threshold region, one with a central Q{sup 2}-value of 0.1 (GeV/c){sup 2} at an incident beam energy E{sub 0} = 0.778 GeV and the other with a central Q{sup 2}-value of 0.2 (GeV/c){sup 2} at E-0 = 1.727 GeV. The average beam current was 10 mu-A, which was mainly due to the limitation of the polarized {sup 3}He target. The measured asymmetry was compared with both plane wave impulse approximation (PWIA) calculations and non-relativistic full Faddeev calculations which include both final-state interactions (FSIs) and meson-exchange currents (MECs) effects. The poor description of the data by PWIA calculations at both Q{sup 2}-values suggests the existence of strong FSI and MEC effects in the threshold region of polarized {sup 3}He (polarized e, e'). Indeed, the agreement between the data and full calculations is very good at Q{sup 2} = 0.1 (GeV/c){sup 2}. On the other hand, a small discrepancy at Q{sup 2} = 0.2 (GeV/c){sup 2} is observed, which might be due to some Q{sup 2} -dependent effects such as relativity and three-nucleon forces (3NFs), which are not included in the framework

  13. Safety analysis of high pressure 3He-filled micro-channels for thermal neutron detection.

    Energy Technology Data Exchange (ETDEWEB)

    Ferko, Scott M.; Galambos, Paul C.; Derzon, Mark Steven; Renzi, Ronald F.

    2008-11-01

    This document is a safety analysis of a novel neutron detection technology developed by Sandia National Laboratories. This technology is comprised of devices with tiny channels containing high pressure {sup 3}He. These devices are further integrated into large scale neutron sensors. Modeling and preliminary device testing indicates that the time required to detect the presence of special nuclear materials may be reduced under optimal conditions by several orders of magnitude using this approach. Also, these devices make efficient use of our {sup 3}He supply by making individual devices more efficient and/or extending the our limited {sup 3}He supply. The safety of these high pressure devices has been a primary concern. We address these safety concerns for a flat panel configuration intended for thermal neutron detection. Ballistic impact tests using 3 g projectiles were performed on devices made from FR4, Silicon, and Parmax materials. In addition to impact testing, operational limits were determined by pressurizing the devices either to failure or until they unacceptably leaked. We found that (1) sympathetic or parasitic failure does not occur in pressurized FR4 devices (2) the Si devices exhibited benign brittle failure (sympathetic failure under pressure was not tested) and (3) the Parmax devices failed unacceptably. FR4 devices were filled to pressures up to 4000 + 100 psig, and the impacts were captured using a high speed camera. The brittle Si devices shattered, but were completely contained when wrapped in thin tape, while the ductile FR4 devices deformed only. Even at 4000 psi the energy density of the compressed gas appears to be insignificant compared to the impact caused by the incoming projectile. In conclusion, the current FR4 device design pressurized up to 4000 psi does not show evidence of sympathetic failure, and these devices are intrinsically safe.

  14. Role of neutron transfer processes on the 6Li+120Sn and 7Li+119Sn fusion reactions

    Directory of Open Access Journals (Sweden)

    Fisichella M.

    2015-01-01

    Full Text Available The results concerning the study of 6Li+120Sn and 7Li+119Sn systems are presented. These two sistems are characterised by very similar structures of the interacting nuclei and by different Q-value for one-and two- neutron transfer. Our aim is to disentangle the possible effects due to the different n-transfer Q-values, at sub-barriers energies, by comparing the two fusion excitation function. In these experiments the fusion cross section has been measured by using a stack activation technique. No particular differences in the two fusion excitation functions have been observed.

  15. {sup 16}O resonances near 4α threshold through {sup 12}C({sup 6}Li,d) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, M. R. D.; Borello-Lewin, T.; Miyake, H.; Horodynski-Matsushigue, L. B.; Duarte, J. L. M.; Rodrigues, C. L.; Faria, P. Neto de [Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, CEP 05314-970, São Paulo, SP (Brazil); Cunsolo, A.; Cappuzzello, F.; Foti, A.; Agodi, C.; Cavallaro, M. [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Napoli, M. di; Ukita, G. M. [Faculdade de Psicologia, Universidade de Santo Amaro, R. Prof. Eneas da Siqueira Neto, 340, CEP 04829-300, São Paulo, SP (Brazil)

    2014-11-11

    Several narrow alpha resonant {sup 16}O states were detected through the {sup 12}C({sup 6}Li,d) reaction, in the range of 13.5 to 17.5 MeV of excitation energy. The reaction was measured at a bombarding energy of 25.5 MeV employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion technique. Experimental angular distributions associated with natural parity quasi-bound states around the 4α threshold are presented and compared to DWBA predictions. The upper limit for the resonance widths obtained is near the energy resolution (15 keV)

  16. Study of Two-Step Mechanisms in Pion Absorption on $^{6}Li$, $^{12}C$ via Deuteron Emission

    CERN Document Server

    Huber, G M; Papandreou, Z; Hovdebo, J; Naqvi, S I H; Ottewell, D F; Walden, P L; Jones, G; Aslanoglou, X

    2000-01-01

    The (pi+,pd), and (pi+,dd) reactions were investigated with pions of 100 and 165 MeV kinetic energy on 6Li and 12C targets. In comparison with previously published (pi+,pp) data on the same targets and at the same beam energies, kinematic regions were identified in which the neutron pickup process n+p->d dominated the observed deuteron yield. The importance of this mechanism increases with energy, contributing half of the observed cross section at 165 MeV. The contribution of direct quasi-triton absorption is significant only at 100 MeV.

  17. Bound Nucleon Properties through 3He(e,e'p) at High Q2

    Energy Technology Data Exchange (ETDEWEB)

    E. Penel-Nottaris

    2002-12-01

    Electron scattering cross-sections for the reaction {sup 3}He(e,e{prime}p)d have been measured in parallel kinematics for three values of the recoil momentum (0 and {+-} 300 MeV/c) and for different values of the virtual photon squared mass Q{sup 2} up to 4.1 GeV{sup 2}. The goal is to probe the electromagnetic properties of the proton when embedded in a nucleus, by studying the Q{sup 2} dependence of the longitudinal and transverse response functions.

  18. Two-Nucleon Momentum Distributions Measured in 3He(e,e'pp)n

    CERN Document Server

    Niyazov, R A; Weinstein, L B; Adams, G; Ambrozewicz, P; Anciant, E; Anghinolfi, M; Asavapibhop, B; Audit, G; Auger, T; Avakian, H; Bagdasaryan, H; Ball, J P; Barrow, S; Battaglieri, M; Beard, K; Bektasoglu, M; Bellis, M; Benmouna, N; Berman, Barry L; Bianchi, N; Biselli, A S; Boiarinov, S; Bonner, B E; Bouchigny, S; Bradford, R; Branford, D; Brooks, W K; Burkert, V D; Butuceanu, C; Calarco, J R; Carman, D S; Carnahan, B; Cetina, C; Chen, S; Ciciani, L; Cole, P L; Coleman, A; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J P; De Sanctis, E; De Vita, R; Degtyarenko, P V; Denizli, H; Dennis, L; Dharmawardane, K V; Dhuga, K S; Djalali, C; Dodge, G E; Doughty, D C; Dragovitsch, P; Dugger, M; Dytman, S; Dzyubak, O P; Eckhause, M; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Empl, A; Eugenio, P; Fatemi, R; Feuerbach, R J; Ficenec, J; Forest, T A; Funsten, H; Gavalian, G; Gilfoyle, G P; Giovanetti, K L; Girard, P; Gordon, C I O; Griffioen, K; Guidal, M; Guillo, M R; Guo, L; Gyurjyan, V; Hadjidakis, C; Hakobyan, R S; Hardie, J; Heddle, D; Hersman, F W; Hicks, K; Holtrop, M; Hu, J; Hyde-Wright, C E; Ilieva, Y; Ito, M M; Jenkins, D; Joo, K; Jüngst, H G; Kelley, J H; Khandaker, M; Kim, D H; Kim, K Y; Kim, K; Kim, M S; Kim, W; Klein, A; Klein, F J; Klimenko, A V; Klusman, M; Kossov, M; Kramer, L H; Kuang, Y; Kuhn, S E; Kühn, J; Lachniet, J; Laget, J M; Langheinrich, J; Lawrence, D; Ji Li; Lukashin, K; Manak, J J; Marchand, C; McAleer, S; McNabb, J W C; Mecking, B A; Mehrabyan, S S; Melone, J J; Mestayer, M D; Meyer, C A; Mikhailov, K; Mirazita, M; Miskimen, R; Morand, L; Morrow, S A; Muccifora, V; Müller, J; Mutchler, G S; Napolitano, J; Nasseripour, R; Nelson, S O; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Nozar, M; O'Rielly, G V; Osipenko, M; Park, K; Pasyuk, E A; Peterson, G; Philips, S A; Pivnyuk, N; Pocanic, D; Pogorelko, O I; Polli, E; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Qin, L M; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Ronchetti, F; Rossi, P; Rowntree, D; Rubin, P D; Sabatie, F; Sabourov, K; Salgado, C; Santoro, J P; Sapunenko, V; Sargsyan, M; Schumacher, R A; Serov, V S; Shafi, A; Sharabyan, Yu G; Shaw, J; Simionatto, S; Skabelin, A V; Smith, E S; Smith, L C; Sober, D I; Spraker, M; Stavinsky, A V; Stepanyan, S; Stoler, P; Strakovsky, I I; Strauch, S; Taiuti, M; Taylor, S; Tedeschi, D J; Thoma, U; Thompson, R; Todor, L; Tur, C; Ungaro, M; Vineyard, M F; Vlassov, A V; Wang, K; Weller, H; Weygand, D P; Whisnant, C S; Wolin, E; Wood, M H; Yegneswaran, A; Yun, J; Zhang, B

    2004-01-01

    We have measured the 3He(e,e'pp)n reaction at 2.2 GeV over a wide kinematic range. The kinetic energy distribution for `fast' nucleons (p > 250 MeV/c) peaks where two nucleons each have 20% or less, and the third nucleon has most of the transferred energy. These fast pp and pn pairs are back-to-back with little momentum along the three-momentum transfer, indicating that they are spectators. Experimental and theoretical evidence indicates that we have measured distorted two-nucleon momentum distributions by striking the third nucleon and detecting the spectator correlated pair.

  19. Additional Beta due to Fast Fusion Products in D-3He Fusion Plasma

    Institute of Scientific and Technical Information of China (English)

    DENG Bai-Quan(邓柏权); G.A.Emmert; PENG Li-Lin(彭利林)

    2003-01-01

    An analytical formula for the additional beta due to fast fusion-born ions is derived by using the slowing-down approximation from the Fokker-Planck equation under the assumption of negligible loss term. It is found that the fast ion beta in a D-3 He fusion plasma at a typical temperature of 55 ke V is about 20% of the thermal beta,which is the same ratio as that obtained in a D-T plasma at 20keV.

  20. Bogoliubov-normal interaction and calculation of thermal conductivity of superfluid A1-3He

    Science.gov (United States)

    Afzali, R.; Ebrahimian, N.

    2006-09-01

    The diffusive thermal conductivity tensor of the A 1-phase of superfluid 3He at low temperatures and melting pressure are calculated by s-p approximation, by using the Boltzmann equation approach. We obtain that the elements of the diffusive thermal conductivities, Kxx, Kyy, and Kzz, are proportional to T -1. Then we compare the results of this paper and our results of thermal conductivity based on Pfitzner procedure. Temperature dependence of both results is equal but numerical coefficients of them are little different. Also we show that Boguliubov-normal interaction is important in comparison to other interactions.

  1. Molecular (Feshbach) treatment of charge exchange Li/sup 3 +/+He collisions. II. Cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Errea, L.F.; Martin, F.; Mendez, L.; Riera, A.; Yanez, M.

    1986-05-15

    Using the wave functions calculated in the preceding article, and a common translation factor, the charge exchange cross section for the Li/sup 3 +/+He(1s/sup 2/) reaction is calculated, and the mechanism of the process discussed. We show how small deviations from the Landau--Zener model, which are unrelated to Nikitin's conditions for its validity, lead to a minimum of the cross section at an impact energy Eapprox. =1 keV, and to larger values of sigma at intermediate nuclear velocities.

  2. Trapping of ultra cold atoms in a 3He/4He dilution refrigerator

    CERN Document Server

    Jessen, F; Bell, S C; Vergien, P; Hattermann, H; Weiss, P; Rudolph, M; Reinschmidt, M; Meyer, K; Gaber, T; Cano, D; Guenther, A; Bernon, S; Koelle, D; Kleiner, R; Fortagh, J

    2013-01-01

    We describe the preparation of ultra cold atomic clouds in a dilution refrigerator. The closed cycle 3He/4He cryostat was custom made to provide optical access for laser cooling, optical manipulation and detection of atoms. We show that the cryostat meets the requirements for cold atom experiments, specifically in terms of operating a magneto-optical trap, magnetic traps and magnetic transport under ultra high vacuum conditions. The presented system is a step towards the creation of a quantum hybrid system combining ultra cold atoms and solid state quantum devices.

  3. Second-order perturbation theory for 3He and pd scattering in pionless EFT

    CERN Document Server

    König, Sebastian

    2016-01-01

    This work implements pionless effective field theory with the two-nucleon system expanded around the unitarity limit at second order perturbation theory. The expansion is found to converge well. All Coulomb effects are treated in perturbation theory, including two-photon contributions at next-to-next-to-leading order. After fixing a three-nucleon force to the 3He binding energy at this order, proton-deuteron scattering in the doublet S-wave channel is calculated for moderate center-of-mass momenta.

  4. Low-density phases of 3He monolayers adsorbed on graphite

    Science.gov (United States)

    Ruggeri, Michele; Vitali, Ettore; Galli, Davide Emilio; Boninsegni, Massimo; Moroni, Saverio

    2016-03-01

    Quantum Monte Carlo simulations at zero temperature of a 3He monolayer adsorbed on graphite, either clean or preplated with 4He, unexpectedly point to a gas-liquid phase transition at a very low areal density of the order of 0.01 Å-2 . This result stems from an essentially unbiased calculation of the ground-state energy for an infinite, defect-free substrate, which interacts with He atoms via a realistic potential, whereas the interaction between two He atoms includes two- and three-body terms. The sensitivity of the gas-liquid coexistence region on the model Hamiltonian employed is discussed.

  5. Development of a 3He nuclear spin flip system on an in-situ SEOP 3He spin filter and demonstration for a neutron reflectometer and magnetic imaging technique

    Science.gov (United States)

    Hayashida, H.; Oku, T.; Kira, H.; Sakai, K.; Hiroi, K.; Ino, T.; Shinohara, T.; Imagawa, T.; Ohkawara, M.; Ohoyama, K.; Kakurai, K.; Takeda, M.; Yamazaki, D.; Oikawa, K.; Harada, M.; Miyata, N.; Akutsu, K.; Mizusawa, M.; Parker, J. D.; Matsumoto, Y.; Zhang, S.; Suzuki, J.; Soyama, K.; Aizawa, K.; Arai, M.

    2016-04-01

    We have been developing a 3He neutron spin filter (NSF) using the spin exchange optical pumping (SEOP) technique. The 3He NSF provides a high-energy polarized neutron beam with large beam size. Moreover the 3He NSF can work as a π-flipper for a polarized neutron beam by flipping the 3He nuclear spin using a nuclear magnetic resonance (NMR) technique. For NMR with the in-situ SEOP technique, the polarization of the laser must be reversed simultaneously because a non-reversed laser reduces the polarization of the spin-flipped 3He. To change the polarity of the laser, a half-wavelength plate was installed. The rotation angle of the half-wavelength plate was optimized, and a polarization of 97% was obtained for the circularly polarized laser. The 3He polarization reached 70% and was stable over one week. A demonstration of the 3He nuclear spin flip system was performed at the polarized neutron reflectometer SHARAKU (BL17) and NOBORU (BL10) at J-PARC. Off-specular measurement from a magnetic Fe/Cr thin film and magnetic imaging of a magnetic steel sheet were performed at BL17 and BL10, respectively.

  6. Simulation of ion chamber signals in the n+3 He -> p + t experiment

    Science.gov (United States)

    Coppola, Christopher; n3He Collaboration

    2017-01-01

    The parity violating proton directional asymmetry from the capture of polarized neutrons on 3He was measured with a pulsed neutron beam at the Spallation Neutron Source at Oak Ridge National Laboratory. The target is an ion chamber with 3He at 0.476 atmosphere. Signal wires in the chamber have different sensitivities to the physics asymmetry, depdendent on their location and the configuration of the experiment. These geometry factors must be determined by simulation. In addition, simulation estimates the statistical precision of the experiment, optimizes configuration variables, and assists with systematic analysis. To achieve the most accurate simulation of the detector signals, a custom simulation was written in C++ using weighted variables and taking advantage of parallel execution. The phsyics inputs to the simulation came from measurements of the neutron phase space, ENDF cross sections, and PSTAR ionization data. A cell model was applied to combine this physics to produce an accurate simulation of the experimental data. This simulation can be used to calculate accurate and tunable geometry factors, and to produce desired quanities for use in optimization and analysis.

  7. On chiral magnetic effect in Weyl superfluid 3He-A

    CERN Document Server

    Volovik, G E

    2016-01-01

    In the theory of the chiral anomaly in relativistic quantum field theories (RQFT) some results depend on regularization scheme at ultraviolet. In the chiral superfluid 3He-A, which contains two Weyl points and also experiences the effects of chiral anomaly, the "trans-Planckian" physics is known and the results can be obtained without regularization. We discuss this on example of the chiral magnetic effect (CME), which has been observed in 3He-A in 90's. There are two forms of the contribution of the CME to the Chern-Simons term in free energy, perturbative and non-perturbative. The perturbative term comes from the fermions living in the vicinity of the Weyl point, where the fermions are "relativistic" and obey the Weyl equation. The non-perturbative term originates from the deep vacuum, being determined by the separation of the two Weyl points. Both terms are obtained using the Adler-Bell-Jackiw equation for chiral anomaly, and both agree with the results of the microscopic calculations in the "trans-Plancki...

  8. On Nambu's Fermion-Boson Relations for Superfluid $^3$He-B

    CERN Document Server

    Sauls, J A

    2016-01-01

    Superfluid $^3$He is a spin-triplet ($S=1$), p-wave ($L=1$) BCS condensate of Cooper pairs with total angular momentum $J=0$ in the ground state. In addition to the breaking of $U(1)$ gauge symmetry, separate spin or orbital rotation symmetry is broken to the maximal sub-group, $SO(3)_S\\times SO(3)_L\\rightarrow SO(3)_J$. The Fermions acquire mass, $m_F\\equiv\\Delta$, where $\\Delta$ is the BCS gap. There are also 18 Bosonic excitations - 4 Nambu-Goldstone (NG) modes and 14 massive amplitude Higgs (AH) modes. The Bosonic modes are labelled by the total angular momentum, $J\\in\\{0,1,2\\}$, and parity under particle-hole symmetry, $C=\\pm 1$. For each pair of angular momentum quantum numbers, $J,J_z$, there are two Bosonic partners with $C=\\pm 1$. Based this spectrum Nambu proposed a sum rule connecting the Fermion and Boson masses for BCS type theories, which for $^3$He-B is $M_{J^+}^2 + M_{J^-}^2 = 4m_F^2$ for each family of Bosonic modes labelled by $J$, where $M_{J^C}$ is the mass of the Bosonic mode with quantum...

  9. Nuclear structure corrections to the Lamb shift in $\\mu^3$He$^+$ and $\\mu^3$H

    CERN Document Server

    Dinur, N Nevo; Bacca, S; Barnea, N

    2015-01-01

    Measuring the 2S-2P Lamb shift in a hydrogen-like muonic atom allows one to extract its nuclear charge radius with a high precision that is limited by the uncertainty in the nuclear structure corrections. The charge radius of the proton thus extracted was found to be 7-sigma away from the CODATA value, in what has become the yet unsolved "proton radius puzzle". Further experiments currently aim at the isotopes of hydrogen and helium: the precise extraction of their radii may provide a hint at the solution of the puzzle. We present the first ab initio calculation of nuclear structure corrections, including the nuclear polarization correction, to the 2S-2P transition in $\\mu^3$He$^+$ and $\\mu^3$H, and assess solid theoretical error bars. Our predictions reduce the uncertainty in the nuclear structure corrections to the level of a few percents and will be instrumental to the on-going $\\mu^3$He$^+$ experiment. We also support the mirror $\\mu\\,^3$H system as a candidate for further probing of the nucleon polarizab...

  10. (83)Kr nuclear magnetic moment in terms of that of (3)He.

    Science.gov (United States)

    Makulski, Włodzimierz

    2014-08-01

    High resolution NMR spectroscopy was applied to precisely determine the (83)Kr nuclear magnetic dipole moment on the basis of new results available for nuclear magnetic shielding in krypton and helium-3 atoms. Small amounts of (3)He as the solutes and (83)Kr as the buffer gas were observed in (3)He and (83)Kr NMR spectra at the constant external field, B0 = 11.7578 T. In each case, the resonance frequencies (ν(He) and ν(Kr)) were linearly dependent on the density of gaseous solvent. The extrapolation of experimental points to the zero density of gaseous krypton allowed for the evaluation of both resonance frequencies free from intermolecular interactions. By combining these measurements with the recommended (83)Kr chemical shielding value, the nuclear magnetic moment could be determined with much better precision than ever before, μ((83)Kr) = -0.9707297(32)μN, with the improvement due to the greater accuracy of the spectral data.

  11. Design and performance of an absolute $^3$He/Cs magnetometer

    CERN Document Server

    Koch, H -C; Grujić, Z D; Heil, W; Kasprzak, M; Knowles, P; Kraft, A; Pazgalev, A; Schnabel, A; Voigt, J; Weis, A

    2015-01-01

    We report on the design and performance of a highly sensitive combined $^3$He/Cs magnetometer for the absolute measurement of magnetic fields. The magnetometer relies on the magnetometric detection of the free spin precession of nuclear spin polarized $^3$He gas by optically pumped cesium magnetometers. We plan to deploy this type of combined magnetometer in an experiment searching for a permanent electric dipole moment of ultracold neutrons at the Paul Scherrer Institute (Switzerland). A prototype magnetometer was built at the University of Fribourg (Switzerland) and tested at Physikalisch-Technische Bundesanstalt (Berlin, Germany). We demonstrate that the combined magnetometer allows Cram\\'er-Rao- limited field determinations with recording times in the range of $10\\sim 500\\text{s}$, measurements above $500\\text{s}$ being limited by the stability of the applied magnetic field. With a $100\\text{s}$ recording time we were able to perform an absolute measurement of a magnetic field of $\\approx 1\\mu \\text{T}$ w...

  12. A measurement of the parity violating asymmetry in the neutron capture on 3He at SNS

    Science.gov (United States)

    Kabir, Latiful; n-3He Collaboration

    2016-09-01

    Weak nucleon nucleon couplings are largely unknown because of it's non-perturbative nature which makes the calculations and experiments challenging. However, parity violation (PV) can be used to isolate the weak contributions from the strong part and thus studies of PV in hadronic systems offer a unique probe of nucleon structure. The n-3He experiment at the Spallation Neutron Source at the ORNL measures the parity violating asymmetry of the recoil proton momentum k->p with respect to the neutron spin σ->n in the reaction n +3He -> p + T + 765keV . This asymmetry is sensitive to the isospin-conserving and isospin-changing (ΔI = 0,1) parts of the Hadronic Weak Interaction, and is expected to be extremely small ( 10-7). The experiment will determine this PV asymmetry with the statistical sensitivity of the order of 10-8. Last year we completed the data taking and the data analysis is well advanced. I will describe the experiment and present the preliminary analysis of the PV asymmetry data of the experiment.

  13. Q2 Evolution of the Neutron Spin Structure Moments using a 3He Target

    Energy Technology Data Exchange (ETDEWEB)

    M. Amarian; L. Auerbach; T. Averett; J. Berthot; P. Bertin; B. Bertozzi; T. Black; E. Brash; D. Brown; E. Burtin; J. Calarco; G. Cates; Z. Chai; J.P. Chen; Seon-ho Choi; E. Chudakov; E. Cisbani; C.W. de Jager; A. Deur; R. DiSalvo; S. Dieterich; P. Djawotho; M. Finn; K. Fissum; H. Fonvieille; S. Frullani; H. Gao; J. Gao; F. Garibaldi; A. Gasparian; S. Gilad; R. Gilman; A. Glamazdin; C. Glashausser; E. Goldberg; J. Gomez; V. Gorbenko; J.O. Hansen; B. Hersman; R. Holmes; G.M. Huber; E. Hughes; B. Humensky; S. Incerti; M. Iodice; S. Jensen; X. Jiang; C. Jones; G. Jones; M. Jones; C. Jutier; A. Ketikyan; I. Kominis; W. Korsch; K. Kramer; K. Kumar; G. Kumbartzki; M. Kuss; E. Lakuriqi; G. Laveissiere; J. Lerose; M. Liang; N. Liyanage; G. Lolos; S. Malov; J. Marroncle; K. McCormick; R. Mckeown; Z.E. Meziani; R. Michaels; J. Mitchell; Z. Papandreou; T. Pavlin; G.G. Petratos; D. Pripstein; D. Prout; R. Ransome; Y. Roblin; D. Rowntree; M. Rvachev; F. Sabatie; A. Saha; K. Slifer; P. Souder; T. Saito; S. Strauch; R. Suleiman; K. Takahashi; S. Teijiro; L. Todor; H. Tsubota; H. Ueno; G. Urciuoli; R. Van der Meer; P. Vernin; H. Voskanian; B. Wojtsekhowski; F. Xiong; W. Xu; J.C. Yang; B. Zhang; P. Zolnierczuk

    2004-01-01

    We have measured the spin structure functions g{sub 1} and g{sub 2} of {sup 3}He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.07 GeV off a polarized {sup 3}He target at a 15.5{sup o} scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q{sup 2} evolution of {Gamma}{sub 1}(Q{sup 2})=/int{sub 0}{sup 1} g{sub 1}(x,Q{sup 2}) dx, {Gamma}{sub 2}(Q{sup 2})=/int{sub 0}{sup 1} g{sub 2}(x,Q{sup 2}) dx and d{sub 2} (Q{sup 2}) = /int{sub 0}{sup 1} x {sup 2}[2g{sub 1}(x,Q{sup 2}) + 3g{sub 2}(x,Q{sup 2})] dx for the neutron in the range 0.1 GeV{sup 2} /leq Q{sup 2} /leq 0.9 GeV{sup 2} with good precision. {Gamma}{sub 1}(Q{sup 2}) displays a smooth variation from high to low Q{sup 2}. The Burkhardt-Cottingham sum rule holds within uncertainties and d{sub 2} is non-zero over the measured range.

  14. Ultrasonic Spectroscopy in Liquid ^3He in 98% Porosity Aerogel by Direct Propagation

    Science.gov (United States)

    Choi, H. C.; Masuhara, N.; Park, J.-H.; Meisel, M. W.; Lee, Y.; Mulders, N.

    2006-03-01

    Systematic investigations on the effect of static disorder on p-wave superfluid ^3He have been made possible by utilizing its unique structure of high porosity silica aerogel. For the past 10 years, a burst of experimental effort revealed that three distinct superfluid phases exist in the P-H-T phase diagram of the ^3He/98% aerogel system. These three phases are conveniently named the A-, B-, and A1-phases as in the bulk, although only spin structures of the superfluid phases have been identified. In particular, the verdict on the so called A-phase is by no means conclusive. As has been the case in the bulk, for a clear identification of the order parameter structure, both spin and orbital components need to be examined. We report our preliminary results of sound propagation in an attempt to directly investigate the orbital structure of the superfluid phases in 98% aerogel using a pulsed ultrasound spectroscopic technique. Preliminary data for the transmission and the surface impedance will be presented.

  15. Measurement of the excitation function of {sup 65}Cu({sup 3}He,2n){sup 66}Ga; Medida da funcao excitacao da reacao {sup 65} Cu({sup 3} He,2n) {sup 66} Ga

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, M.A.V.; Vinagre Filho, U.M.; Costa, V.L. da [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil)

    1996-07-01

    The excitation function of the {sup 65} Cu({sup 3} He,2n) {sup 66} Ga reaction was measured. It was performed by irradiation of several stacks of two copper foils with {sup 3} He until 36 MeV from the cyclotron CV-28 of IEN. The initial energy of {sup 3} He beam was measured by spectrometry of charged particles with Si (au) detector, placed at 90 deg C respecting to the incident beam. The activities was measured by gamma rays spectrometry using HPGe detector. The results are compared with others found in the literature. (author)

  16. Theoretical study of the $\\alpha+d$ $\\rightarrow$ $^6$Li + $\\gamma $ astrophysical capture process in a three-body model

    CERN Document Server

    Tursunov, E M; Turakulov, S A; Bray, I

    2016-01-01

    The astrophysical capture process $\\alpha+d$ $\\rightarrow$ $^6$Li + $\\gamma$ is studied in a three-body model. The initial state is factorized into the deuteron bound state and the $\\alpha+d$ scattering state. The final nucleus $^6$Li(1+) is described as a three-body bound state $\\alpha+n+p$ in the hyperspherical Lagrange-mesh method. The contribution of the E1 transition operator from the initial isosinglet states to the isotriplet components of the final state is estimated to be negligible. An estimation of the forbidden E1 transition to the isosinglet components of the final state is comparable with the corresponding results of the two-body model. However, the contribution of the E2 transition operator is found to be much smaller than the corresponding estimations of the two-body model. The three-body model perfectly matches the new experimental data of the LUNA collaboration with the help of the spectroscopic factor 2.586, very consistent with the three-body structure of the final state.

  17. Analysis of the normal optical, Michel and molecular potentials on the $^{40}$Ca($^6$Li, d)$^{44}$ Ti reaction

    Indian Academy of Sciences (India)

    MAZUMDER UTTAM K; SOMADDER ANOCK; HOQUE ENAMUL; HAQUE YASMEEN; DAS SUSANTA K; SEN GUPTA H M

    2016-06-01

    Full finite-range (FFR) distorted-wave Born approximation (DWBA) method has been applied to analyse the angular distributions of cross-sections of the $^{40}$Ca($^{6}$Li, d)$^{44}$Ti reaction at 28 MeV incident energy for the 22 transitions involving both the bound and unbound states of $^{44}$Ti byusing the normal optical, Michel and molecular potentials. The extracted spectroscopic factors for the three optical potentials are compared with those of some previous studies of zero-range (ZR) calculations of the$^{40}$Ca($^{6}$Li, d)$^{44}$Ti reaction using the normal optical potential. The $\\chi^{2}$ values of all the levels are obtained for the three optical potentials to estimate the quality of the fits. Molecular and Michel potentials have been used for the first time to analyse the four-nucleon transfer reaction and it seems that the molecular potential fits the experimental data more satisfactorily for some of the states than the normal optical and Michel potentials.

  18. Low energy R-matrix fits for the 6Li(d,a)4He S factor

    CERN Document Server

    Grineviciute, J; Lamia, L; Spitaleri, C; La Cognata, M

    2014-01-01

    Background: The information about the 6Li(d,a)4He reaction rates of the astrophysical interest can be obtained by extrapolating direct data to the lower energies, or by indirect methods. The indirect Trojan Horse method, as well as various R-matrix and polynomial fits to direct data, estimate the electron screening energies much larger than the adiabatic limit. Calculations that include the subthreshold resonance estimate smaller screening energies. Purpose: Obtain the 6Li(d,a)4He reaction R-matrix parameters and the astrophysical S factor for the energies relevant to the stellar plasmas by fitting the R-matrix formulas for the subthreshold resonances to the S factor data above 60 keV. Methods: The bare S factor is calculated using the single and the two-level R-matrix formulas for the closest to the threshold 0+ and 2+ subthreshold states at 22.2, 20.2 and 20.1 MeV. The electron screening potential Ue is then obtained by fitting it as a single parameter to the low energy data. Results: The low energy S facto...

  19. Resonance and non-resonance effect of continuum states of 6Li on elastic scattering angular distributions

    Science.gov (United States)

    Gómez Camacho, A.

    2016-07-01

    CDCC calculations of elastic scattering angular distributions for reactions of the weakly bound projectile 6Li with targets 28Si and 58Ni at energies around the Coulomb barrier are presented. Special emphasis is given to account for the effect of couplings from 6Li resonance states l = 2, J π = 3+, 2+, 1+. Similarly, the effect produced by non-resonant state couplings is studied. The convergent calculations are carried out with global α-target and d-target interactions. The calculated elastic scattering angular distributions are in general in good agreement with the measurements for the systems considered in this work. It is found that the calculations with only resonance states are very similar to that with all couplings (resonance+non-resonance). So, the absence of these states have a strong effect on elastic scattering (non-resonance states calculation). It is shown that the effects increase as the collision energy increases. An interpretation of the strength of the different effects is given in terms of the polarization potentials that emerge from the different couplings.

  20. Studies on the atomic capture of stopped negative pions in binary mixtures of /sup 3/He with other gases

    Energy Technology Data Exchange (ETDEWEB)

    Bannikov, A.V.; Levay, B.; Petrukhin, V.I.; Vasilyev, V.A. (Joint Inst. for Nuclear Research, Dubna (USSR)); Kochenda, L.M.; Markov, A.A.; Medvedev, V.I.; Sokolov, G.L.; Strakovsky, I.I. (Leningrad Nuclear Physics Inst., Gatchina (USSR)); Horvath, D. (Hungarian Academy of Sciences, Budapest. Central Research Inst. for Physics)

    1983-07-25

    Systematic experimental study has been carried out on the atomic capture of negative pions by /sup 3/He in binary gas mixtures of /sup 3/He + Z, where Z is Ne, Ar, Kr, Xe, N/sub 2/, O/sub 2/, CO/sub 2/ and SF/sub 6/. The results are analysed in the framework of a phenomenological model. It is shown that there is no pion transfer from the /sup 3/He..pi../sup -/ mesic atoms to the heavier Z-atoms. The probabilities of pion capture in the various atoms of the mixtures are found to be proportional to the atomic concentraions, thereby excluding the possibility of a concentration dependence in the atomic capture ratio A(Z//sup 3/He). In contradiction to previous assumptions the probability of pion capture into an atomic orbit is not proportional to the stopping power of the components of the mixture. The atomic capture ratio of pions in a /sup 3/He + /sup 4/He mixture is A(/sup 4/He//sup 3/He) = 0.75 +- 0.13, which might be the indication of an isotopic effect. The branching ratio for the charge-exchange reaction at rest ..pi../sup -/ + /sup 3/He -> ..pi../sup 0/ + /sup 3/H) is found to be 0.128 +- 0.012.

  1. Studies on the atomic capture of stopped negative pions in binary mixtures of 3He with other gases

    Science.gov (United States)

    Bannikov, A. V.; Lévay, B.; Petrukhin, V. I.; Vasilyev, V. A.; Kochenda, L. M.; Markov, A. A.; Medvedev, V. I.; Sokolov, G. L.; Strakovsky, I. I.; Horváth, D.

    1983-07-01

    Systematic experimental study has been carried out on the atomic capture of negative pions by 3He in binary gas mixtures of 3He + Z, where Z is Ne, Ar, Kr, Xe, N 2, O 2, CO 2 and sf 6. The results are analysed in the framework of a phenomenological model. It is shown that there is no pion transfer from the 3Heπ - mesic atoms to the heavier Z-atoms. The probabilities of pion capture in the various atoms of the mixtures are found to be proportional to the atomic concentrations, thereby excluding the possibility of a concentration dependence in the atomic capture ratio A( Z/ 3He). In contradiction to previous assumptions the probability of pion capture into an atomic orbit is not proportional to the stopping power of the components of the mixture. The atomic capture ratio of pions in a 3He + 4He mixture is A( 4He/ 3He) = 0.75 ± 0.13 , which might be the indication of an isotopic effect. The branching ratio for the charge-exchange reaction at rest (π - + 3He → π 0 + 3H) is found to be 0.128 ± 0.012.

  2. Studies on the atomic capture of stopped negative pions in binary mixtures of /sup 3/He with other gases

    Energy Technology Data Exchange (ETDEWEB)

    Bannikov, A.V.; Levay, B.; Petrukhin, V.I.; Vasilyev, V.A. (Joint Inst. for Nuclear Research, Dubna (USSR)); Kochenda, L.M.; Markov, A.A.; Medvedev, V.I.; Sokolov, G.L.; Strakovsky, I.I. (Leningrad Nuclear Physics Inst., Gatchina (USSR)); Horvath, D. (Hungarian Academy of Sciences, Budapest. Central Research Inst. for Physics)

    1983-07-25

    Systematic experimental study has been carried out on the atomic capture of negative pions by /sup 3/He in binary gas mixtures of /sup 3/He + Z, where Z is Ne, Ar, Kr, Xe, N/sub 2/, O/sub 2/, CO/sub 2/ and SF/sub 6/. The results are analyzed in the framework of a phenomenological model. It is shown that there is no pion transfer from the /sup 3/He..pi../sup -/ mesic atoms to the heavier Z-atoms. The probabilities of pion capture in the various atoms of the mixtures are found to be proportional to the atomic concentraions, thereby excluding the possibility of a concentration dependence in the atomic capture ratio A(Z//sup 3/He). In contradiction to previous assumptions the probability of pion capture into an atomic orbit is not proportional to the stopping power of the components of the mixture. The atomic capture ratio of pions in a /sup 3/He + /sup 4/He mixture is A(/sup 4/He//sup 3/He) = 0.75 +- 0.13, which might be the indication of an isotopic effect. The branching ratio for the charge-exchange reaction at rest ..pi../sup -/ + /sup 3/He -> ..pi../sup 0/ + /sup 3/H is found to be 0.128 +- 0.012.

  3. Near Threshold Two Meson Production with the pd {yields} {sup 3}He{pi}{sup +}{pi}{sup {minus}} and pd {yields} {sup 3}HeK{sup +}K{sup {minus}} Reactions

    Energy Technology Data Exchange (ETDEWEB)

    COSY-MOMO Collaboration

    2000-12-31

    Near-threshold two-meson production via the reactions pd {yields} {sup 3}He{pi}{sup +}{pi}{sup {minus}} and pd {yields} {sup 3}HeK{sup +}K{sup {minus}} was measured kinematically complete with the MOMO experiment at COSY. The obtained two-pion variant mass spectra and angular distributions depict a remarkable deviation from phase space. The two-kaon data are consistent with phase space topped by a clear signal of the {phi} meson.

  4. Prospective conceptual qualification of hybrid centrifugation/distillatory for {sup 6}LI nuclear fusion technology scaled supply demands; Calificacion conceptual prospectiva de centrifugador/destilador hibrido para produccion de {sup 6}Li a demanda de la tecnologia Nuclear Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Sedano, L.; Herranz, J. L.; Casado, J. L.; Castro, P.; Xiberta, J.

    2013-07-01

    The change in the demand for exploitation of lithium as a resource appears during the last decade, related to the development of the ion-Li batteries market and with the requirements of Nuclear Fusion fuels (deuterium and lithium) as coming energy option. A prospective analysis of synergistic demands of both markets, in its technical and in its economic aspects appears of prospective interest. The civil market {sup 6}Li/{sup 7}Li enrichment demand is analyzed. Specific technological developments permitting on-line production according to demand is discussed. A [centrifugation /thermal diffusion / combined distillation] technique is selected and qualified as technologically viable option for scaled production of litiated-forms. A conceptual design of a production plant is finally proposed according to the new technical capability.

  5. 同位素7Li和6Li的性质殊异%The diverse of isotopes 7 Li and 6 Li

    Institute of Scientific and Technical Information of China (English)

    朱正和; 宋江锋; 罗德礼

    2014-01-01

    本文研究了同位素7 Li和6 Li在几个方面的性质差异.用相对论量子力学计算指出,6 Li的电子能级比7 Li的能级低,同时,对电偶极E (1)和磁偶极M (1)的能级跃迁波长,6 Li的跃迁波长都要比7 Li的长.由于7 Li和6 Li的核自旋的大小不同,可以看出在磁场2万高斯和温度100-20 K之间,7 Li的磁极化比6 Li的约大13倍.7 Li和6 Li的磁极化这种差异,也是一种可能的同位素7 Li/6 Li的分离方法.%The diverse of isotopes 7 Li and 6 Li was examined on the several respects.The calculations of relativistic quantum mechanics shows that the energy levels of 6 Li are lower than that of 7 Li, and therefore the transitional wave length of E(1) and M(1) for 6 Li are longer than that of 7 Li.The variation of couple constant due to the different nu-clear spin of 7 Li and 6 Li could be as a basis for the isotope separation between 7 Li and 6 Li.Ratio of the molar intensi-ty of magnetization of 7 Li to 6 Li is about 13 under 100-20 K and 20, 000 gauss, which is favorable to separate out 6 Li.

  6. Study of $^{26}$Mg through 1p pick up reaction $^{27}$Al(d,$^{3}$He)

    CERN Document Server

    Srivastava, Vishal; Rana, T K; Manna, S; Kundu, S; Bhattacharya, S; Banerjee, K; Roy, P; Pandey, R; Mukherjee, G; Ghosh, T K; Meena, J K; Roy, T; Chaudhuri, A; Sinha, M; Saha, A K; Asgar, Md A; Dey, A; Roy, Subinit; Shaikh, Md M

    2015-01-01

    The even-even nucleus $^{26}$Mg has been studied through the reaction $^{27}$Al(d,$^{3}$He) at 25 MeV beam energy. The spectroscopic factors have been extracted upto 7.50 MeV excitation energy using local, zero range distorted wave Born approximation. The comparison of the spectroscopic factors have been done with previously reported values using the same reaction probe. The extracted spectroscopic factors for different excited states were found to be in good agreement with the previously reported values for the same. The present results were also compared with the predictions from shell model as well as rotational model. The analog states of $^{26}$Al and $^{26}$Mg were found to be in good agreement.

  7. ABC effect and resonance structure in the double-pionic fusion to 3He

    Science.gov (United States)

    Adlarson, P.; Augustyniak, W.; Bardan, W.; Bashkanov, M.; Bergmann, F. S.; Berłowski, M.; Bhatt, H.; Bondar, A.; Büscher, M.; Calén, H.; Ciepał, I.; Clement, H.; Coderre, D.; Czerwiński, E.; Demmich, K.; Doroshkevich, E.; Engels, R.; Erven, A.; Erven, W.; Eyrich, W.; Fedorets, P.; Föhl, K.; Fransson, K.; Goldenbaum, F.; Goslawski, P.; Goswami, A.; Grigoryev, K.; Gullström, C.-O.; Hauenstein, F.; Heijkenskjöld, L.; Hejny, V.; Höistad, B.; Hüsken, N.; Jarczyk, L.; Johansson, T.; Kamys, B.; Kemmerling, G.; Khan, F. A.; Khoukaz, A.; Kirillov, D. A.; Kistryn, S.; Kleines, H.; Kłos, B.; Krzemień, W.; Kulessa, P.; Kupść, A.; Kuzmin, A.; Lalwani, K.; Lersch, D.; Lorentz, B.; Magiera, A.; Maier, R.; Marciniewski, P.; Mariański, B.; Mikirtychiants, M.; Morsch, H.-P.; Moskal, P.; Ohm, H.; Ozerianska, I.; Perez del Rio, E.; Piskunov, N. M.; Podkopał, P.; Prasuhn, D.; Pricking, A.; Pszczel, D.; Pysz, K.; Pyszniak, A.; Ritman, J.; Roy, A.; Rudy, Z.; Sawant, S.; Schadmand, S.; Sefzick, T.; Serdyuk, V.; Shwartz, B.; Siudak, R.; Skorodko, T.; Skurzok, M.; Smyrski, J.; Sopov, V.; Stassen, R.; Stepaniak, J.; Stephan, E.; Sterzenbach, G.; Stockhorst, H.; Ströher, H.; Szczurek, A.; Täschner, A.; Trzciński, A.; Varma, R.; Wagner, G. J.; Wolke, M.; Wrońska, A.; Wüstner, P.; Wurm, P.; Yamamoto, A.; Yurev, L.; Zabierowski, J.; Zieliński, M. J.; Zink, A.; Złomańczuk, J.; Żuprański, P.; Żurek, M.; WASA-at-COSY Collaboration

    2015-01-01

    Exclusive and kinematically complete measurements of the double pionic fusion to 3He have been performed in the energy region of the so-called ABC effect, which denotes a pronounced low-mass enhancement in the π π -invariant mass spectrum. The experiments were carried out with the WASA detector setup at COSY (the cooler synchrotron at Forschungszentrum Jülich). Similar to the observations in the basic p n →d π0π0 reaction and in the d d →4He π0π0 reaction, the data reveal a correlation between the ABC effect and a resonance-like energy dependence in the total cross section. Differential cross sections are well described by the hypothesis of d* resonance formation during the reaction process in addition to the conventional t -channel Δ Δ mechanism. The deduced d* resonance width can be understood from collision broadening due to Fermi motion of the nucleons in initial and final nuclei.

  8. Effect of a magnetic field on fourth sound in /sup 3/He

    Energy Technology Data Exchange (ETDEWEB)

    Daly, K.

    1988-05-01

    The influence of a magnetic field on the propagation of fourth sound in superfluid /sup 3/He is studied. The field and temperature dependences of the average superfluid density /anti rho//sub s///rho/ and fourth sound Q are measured. The field dependence of /anti rho//sub s///rho/ is very different in a porous medium than predicted by Ginzburg-Landau theory applied to bulk liquid. In particular, a magnetic suppression of /anti rho//sub s///rho/ is observed in the temperature and pressure ranges corresponding to the A phase in bulk liquid. There is strong evidence of a magnetic suppression of T/sub c/ itself. The measured /anti rho//sub s///rho/ has a slight history dependence in a magnetic field, but none in zero field. The fourth-sound Q values are compared to the theoretical work of Smith, Jensen, and Wolfle. Quantitative confirmation of their work is problematic.

  9. Meson exchange currents in the {sup 3}He({gamma},{pi}{sup +}){sup 3}H reaction

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Tejedor, J.A.; Kamalov, S.S.; Oset, E. [Departamento de Fisica Teorica and Instituto de Fsica Corpuscular, Centro Mixto Universidad de Valencia--Consejo Superior de Investigaciones Cientificas, 46100 Burjassot (Valencia) (Spain)

    1996-12-01

    We generate meson exchange currents mechanisms for the ({gamma},{pi}{sup +}) reaction in nuclei starting from the {gamma}{ital N}{r_arrow}{pi}{pi}{ital N} amplitude on one nucleon and allowing one of the pions to be produced off shell and be absorbed by a second nucleon. Detailed calculations are presented for the {gamma} {sup 3}He{r_arrow}{pi}{sup +}{sup 3}H reaction, where we show that the cross section at large momentum transfers is dominated by these mechanisms, helping improve the agreement with experimental data. It is also shown that the meson exchange currents produce important effects in the photon asymmetry in the {Delta}-resonance region. {copyright} {ital 1996 The American Physical Society.}

  10. On Larkin-Imry-Ma State of 3He-A in Aerogel

    CERN Document Server

    Volovik, G E

    2007-01-01

    Superfluid 3He-A shares the properties of spin nematic and chiral orbital ferromagnet. Its order parameter is characterized by two vectors d and l. This doubly anisotropic superfluid, when it is confined in aerogel, represents the most interesting example of a system with continuous symmetry in the presence of random anisotropy disorder. We discuss the Larkin-Imry-Ma state, which is characterized by the short-range orientational order of the vector l, while the long-range orientational order is destroyed by the collective action of the randomly oriented aerogel strings. On the other hand, sufficiently large regular anisotropy produced either by the deformation of the aerogel or by applied superflow destroys the Larkin-Imry-Ma effect leading to the uniform orientation of the vector l. This interplay of regular and random anisotropy allows us to study many different effects.

  11. Tensor Correlations Measured in 3He(e,e'pp)n

    CERN Document Server

    Baghdasaryan, H; Laget, J M; Adhikari, K P; Aghasyan, M; Amarian, M; Anghinolfi, M; Avakian, H; Ball, J; Battaglieri, M; Bedlinskiy, I; Berman, B L; Biselli, A S; Bookwalter, C; Briscoe, W J; Brooks, W K; B?ultmann, S; Burkert, V D; Carman, D S; Crede, V; D'Angelo, A; Daniel, A; Dashyan, N; DeVita, R; DeSanctis, E; Deur, A; Dey, B; Dickson, R; Djalali, C; Dodge, G E; Doughty, D; Dupre, R; Egiyan, H; Alaoui, A El; Fassi, L El; Eugenio, P; Fegan, S; Gabrielyan, M Y; Gilfoyle, G P; Giovanetti, K L; Gohn, W; Gothe, R W; Griffioen, K A; Guidal, M; Guo, L; Gyurjyan, V; Hakobyan, H; Hanretty, C; Hyde, C E; Hicks, K; Holtrop, M; Ilieva, Y; Ireland, D G; Joo, K; Keller, D; Khandaker, M; Khetarpal, P; Kim, A; Kim, W; Klein, A; Klein, F J; Konczykowski, P; Kubarovsky, V; Kuhn, S E; Kuleshov, S V; Kuznetsov, V; Kvaltine, N D; Livingston, K; Lu, H Y; MacGregor, I J D; Markov, N; Mayer, M; McAndrew, J; McKinnon, B; Meyer, C A; Mikhailov, K; Mokeev, V; Moreno, B; Moriya, K; Morrison, B; Moutarde, H; Munevar, E; Nadel-Turonski, P; Nepali, C; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Paremuzyan, R; Park, K; Park, S; Pasyuk, E; Pereira, S Anefalos; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Procureur, S; Protopopescu, D; Ricco, G; Ripani, M; Rosner, G; Rossi, P; Sabati?e, F; Salgado, C; Schumacher, R A; Seraydaryan, H; Smith, G D; Sober, D I; Sokhan, D; Stepanyan, S S; Stepanyan, S; Stoler, P; Strauch, S; Taiuti, M; Tang, W; Taylor, C E; Tedeschi, D J; Ungaro, M; Vineyard, M F; Voutier, E; Watts, D P; Weygand, D P; Wood, M H; Zhao, B; Zhao, Z W

    2010-01-01

    We have measured the 3He(e,e'pp)n reaction at an incident energy of 4.7 GeV over a wide kinematic range. We identified spectator correlated pp and pn nucleon pairs using kinematic cuts and measured their relative and total momentum distributions. This is the first measurement of the ratio of pp to pn pairs as a function of pair total momentum, $p_{tot}$. For pair relative momenta between 0.3 and 0.5 GeV/c, the ratio is very small at low $p_{tot}$ and rises to approximately 0.5 at large $p_{tot}$. This shows the dominance of tensor over central correlations at this relative momentum.

  12. Tensor Correlations Measured in 3He(e,e'pp)n

    Energy Technology Data Exchange (ETDEWEB)

    Baghdasaryan, H; Weinstein, L B; Adhikari, K P; Aghasyan, K P; Amarian, M; Anghinolfi, M; Avakian, H; Ball, J; Battaglieri, M; Bedlinskiy, I; Berman, B L; Biselli, A S; Bookwalter, C; Briscoe, W J; Brooks, W K; Boltmann, S; Burkert, V D; Carman, D S; Crede, V; D& #x27; Angelo, A; Daniel, A; Dashyan, N; DeVita, R; DeSanctis, E; Deur, A; Dey, B; Dickson, R; Djalali, C; Dodge, G E; Doughty, D; Dupre, R; Egiyan, H; El Alaoui, A; El Fassi, L; Eugenio, P; Fegan, S; Gabrielyan, M Y; Gilfoyle, G P; Giovanetti, K L; Gohn, W; Gothe, R W; Griffioen, K A; Guidal, M; Guo, L; Gyurjyan, V; Hakobyan, H; Hanretty, C; Hyde, C E; Hicks, K; Holtrop, M; Ilieva, Y; Ireland, D G; Joo, K; Keller, D; Khandaker, M; Khetarpal, P; Kim, A; Kim, W; Klein, A; Klein, F J; Konczykowski, P; Kubarovsky, V; Kuhn, S E; Kuleshov, S V; Kuznetsov, V; Kvaltine, N D; Livingston, K; Lu, H Y; MacGregor, I.J.D.; Markov, N; Mayer, M; McAndrew, J; McKinnon, B; Meyer, C A; Mikhailov, K; Mokeev, V; Moreno, B; Moriya, K; Morrison, B; Moutarde, H; Munevar, E; Nadel-Turonski, P; Nepali, C; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Paremuzyan, R; Park, K; Park, S; Pasyuk, E; Anefalos Pereira, S; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Procureur, S; Protopopescu, D; Ricco, G; Ripani, M; Rosner, G; Rossi, P; Sabatie, F; Salgado, C; Schumacher, R A; Seraydaryan, H; Smith, G D; Sober, D I; Sokhan, D; Stepanyan, S S; Stepanyan, S; Stoler, P; Strauch, S; Taiuti, M; Tang, W; Taylor, C E; Tedeschi, D J; Ungaro, M; Vineyard, M F; Voutier, E; Watts, D P; Weygand, D P; Wood, M H; Zhao, B; Zhao, Z W

    2010-11-01

    We have measured the 3He(e,e'pp)n reaction at an incident energy of 4.7 GeV over a wide kinematic range. We identified spectator correlated pp and pn nucleon pairs by using kinematic cuts and measured their relative and total momentum distributions. This is the first measurement of the ratio of pp to pn pairs as a function of pair total momentum ptot. For pair relative momenta between 0.3 and 0.5 GeV/c, the ratio is very small at low ptot and rises to approximately 0.5 at large ptot. This shows the dominance of tensor over central correlations at this relative momentum.

  13. A 3He gas heat switch for the 0.5-2 K temperature range

    Science.gov (United States)

    Smith, Eric N.; Parpia, Jeevak M.; Beamish, John R.

    2000-07-01

    We have constructed a prototype heat switch for use in a cyclic demagnetization apparatus. The desired operating range of the switch is from 0.5 to 1.8 K. The measured conductivity of the switch is 50 μW/ K at 1.5 K when ‘off ’ and 8 mW/K at 0.5 K when ‘on’. The switching is carried out by 3He gas which is admitted and extracted from the device by a miniature charcoal adsorption pump which is controlled by electrical heat and a weak thermal link to a pumped 4He bath. In this paper we discuss details of construction and the performance as a function of temperature, and consider the switching time between on and off states.

  14. Construction of a $^3$He magnetic force microscope with a vector magnet

    CERN Document Server

    Yang, Jinho; Kim, Yun Won; Shin, Dongwoo; Jeong, Juyoung; Wulferding, Dirk; Yeom, Han Woong; Kim, Jeehoon

    2016-01-01

    We constructed a $^3$He magnetic force microscope operating at the base temperature of 300 mK under a vector magnetic field of 2-2-9 T in the $x-y-z$ direction. Fiber optic interferometry as a detection scheme is employed in which two home-built fiber walkers are used for the alignment between the cantilever and the optical fiber. The noise level of the laser interferometer is close to its thermodynamic limit. The capabilities of the sub-Kelvin and vector field are demonstrated by imaging the coexistence of magnetism and superconductivity in a ferromagnetic superconductor (ErNi$_2$B$_2$C) at $T$=500 mK and by probing a dipole shape of a single Abrikosov vortex with an in-plane tip magnetization.

  15. Status Summary of 3He and Neutron Detection Alternatives for Homeland Security

    Energy Technology Data Exchange (ETDEWEB)

    Kouzes, Richard T.; Ely, James H.

    2010-04-28

    This is a short summary whitepaper on results of our alternatives work: Neutron detection is an important aspect of interdiction of radiological threats for homeland security purposes since plutonium, a material used for nuclear weapons, is a significant source of fission neutrons [Kouzes 2005]. Because of the imminent shortage of 3He, which is used in the most commonly deployed neutron detectors, a replacement technology for neutron detection is required for most detection systems in the very near future [Kouzes 2009a]. For homeland security applications, neutron false alarms from a detector can result in significant impact. This puts a strong requirement on any neutron detection technology not to generate false neutron counts in the presence of a large gamma ray-only source [Kouzes et al. 2008].

  16. Magnetic properties and concurrence for fluid {sup 3}He on kagome lattice

    Energy Technology Data Exchange (ETDEWEB)

    Ananikian, N. S., E-mail: ananik@yerphi.am; Ananikian, L. N. [A.I. Alikhanyan National Science Laboratory (Armenia); Lazaryan, H. A. [Yerevan State University (Armenia)

    2012-10-15

    We present the results of magnetic properties and entanglement for kagome lattice using Heisenberg model with two- and three-site exchange interactions in strong magnetic field. Kagome lattice correspond to the third layer of fluid {sup 3}He absorbed on the surface of graphite. The magnetic properties and concurrence as a measure of pairwise thermal entanglement are studied by means of variational mean-field like treatment based on Gibbs-Bogoliubov inequality. The system exhibits different magnetic behaviors depending on the values of the exchange parameters (J{sub 2}, J{sub 3}). We have obtained the magnetization plateaus at low temperatures. The central theme of the paper is comparing the entanglement and magnetic behavior for kagome lattice. We have found that in the antiferromagnetic region behavior of the concurrence coincides with the magnetic susceptibility one.

  17. Extending the Gutzwiller approximation for liquid {sup 3}He by including intersite correlations

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, D.; Pilgram, S.; Rice, T.M.; Sigrist, M. [Institut fuer Theoretische Physik, ETH Zuerich, 8093 Zuerich (Switzerland)

    2011-08-26

    The simple Gutzwiller approximation, applied to the approach to Mott localization in a half-filled band Hubbard model, gives a remarkably good description of the properties of liquid {sup 3}He as the liquid-solid transition is approached under pressure. The key variable, the density of unbound doubly occupied and empty sites is evaluated keeping only single site correlations. We extend the Gutzwiller approximation to incorporate nearest neighbor correlations. This extension improves the agreement with the experimental evolution of the spin susceptibility and effective mass with pressure, but does not remove the large discrepancy in the compressibility. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. sup 3 He detectors in experiments at the powerful pulsed accelerators

    CERN Document Server

    Boreiko, V F; Grebenyuk, V M; Ivanov, A I; Kalinin, A I; Krylov, A R; Parzhitsky, S S; Slepnev, V M; Stolupin, V A; Wozniak, J

    2002-01-01

    A possibility of using a thermal neutron detector in the high gamma-quantum and bremsstrahlung fields is considered in the paper. The design of the thermal neutron detector consisting of 10 counters filled with sup 3 He under the pressure of 2 atm and enclosed in the polyethylene moderator is described. The results of measuring the neutron recording efficiency and neutron lifetimes by this detector exposed to a neutron flux from the dt-reaction and from the sup 2 sup 5 sup 2 Cf and Pu-Be sources are reported. The thicknesses of the polyethylene moderator and the Pb layer used for suppression of the background in the fields of powerful electromagnetic radiation are optimized.

  19. Realization of administration unit for {sup 3}He with gas recycling

    Energy Technology Data Exchange (ETDEWEB)

    Gueldner, Manuela; Grossmann, Tino; Heil, Werner; Karpuk, Sergei; Otten, Ernst-Wilhelm; Salhi, Zahir [Institute of Physics, University Mainz (Germany); Becker, Stefan; Friesenecker, Andreas; Weiss, Patrick; Zentel, Juergen [ic-automation GmbH, Mainz (Germany); Gast, Klaus K.; Rivoire, Julien; Scholz, Alexander; Schreiber, Laura M.; Terekhov, Maxim; Wolf, Ursula [Department of Radiology, University Mainz (Germany)

    2011-07-01

    Since many years hyperpolarized (HP) noble gases are used for MR-imaging of the lung. In the beginning the HP gas was filled in Tedlar-bags and directly inhaled by the patients. An administration unit was built respectively to the Medical Devices Law to administer patients HP noble gas boli ({sup 3}He,{sup 129}Xe) in defined quantities and at a predefined time during inspiration with high reproducibility and reliability without reducing MR-quality. The patient's airflows are monitored and recorded. It is possible to use gas admixtures, measure the polarization on line and collect the exhaled gas for later recycling. The first images with healthy volunteers were taken with this setup in a clinical study. Current results will be presented.

  20. ABC Effect and Resonance Structure in the Double-Pionic Fusion to $^3$He

    CERN Document Server

    Adlarson, P; Bardan, W; Bashkanov, M; Bergmann, F S; Berłowski, M; Bhatt, H; Bondar, A; Büscher, M; Calén, H; Ciepał, I; Clement, H; Coderre, D; Czerwiński, E; Demmich, K; Doroshkevich, E; Engels, R; Erven, A; Erven, W; Eyrich, W; Fedorets, P; Föhl, K; Fransson, K; Goldenbaum, F; Goslawski, P; Goswami, A; Grigoryev, K; Gullström, C --O; Hauenstein, F; Heijkenskjöld, L; Hejny, V; Höistad, B; Hüsken, N; Jarczyk, L; Johansson, T; Kamys, B; Kemmerling, G; Khan, F A; Khoukaz, A; Kirillov, D A; Kistryn, S; Kleines, H; Kłos, B; Krzemień, W; Kulessa, P; Kupść, A; Kuzmin, A; Lalwani, K; Lersch, D; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Mariański, B; Mikirtychiants, M; Morsch, H -P; Moskal, P; Ohm, H; Ozerianska, I; del Rio, E Perez; Piskunov, N M; Podkopał, P; Prasuhn, D; Pricking, A; Pszczel, D; Pysz, K; Pyszniak, A; Ritman, J; Roy, A; Rudy, Z; Sawant, S; Schadmand, S; Sefzick, T; Serdyuk, V; Shwartz, B; Siudak, R; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Stephan, E; Sterzenbach, G; Stockhorst, H; Ströher, H; Szczurek, A; Täschner, A; Trzciński, A; Varma, R; Wagner, G J; Wolke, M; Wrońska, A; Wüstner, P; Wurm, P; Yamamoto, A; Yurev, L; Zabierowski, J; Zieliński, M J; Zink, A; Złomańczuk, J; Żuprański, P; Żurek, M

    2014-01-01

    Exclusive and kinematically complete measurements of the double pionic fusion to $^3$He have been performed in the energy region of the so-called ABC effect, which denotes a pronounced low-mass enhancement in the $\\pi\\pi$-invariant mass spectrum. The experiments were carried out with the WASA detector setup at COSY. Similar to the observations in the basic $pn \\to d \\pi^0\\pi^0$ reaction and in the $dd \\to ^4$He$\\pi^0\\pi^0$ reaction, the data reveal a correlation between the ABC effect and a resonance-like energy dependence in the total cross section. Differential cross sections are well described by the hypothesis of $d^*$ resonance formation during the reaction process in addition to the conventional $t$-channel $\\Delta\\Delta$ mechanism. The deduced $d^*$ resonance width can be understood from collision broadening due to Fermi motion of the nucleons in initial and final nuclei.

  1. On the Nambu fermion-boson relations for superfluid 3He

    Science.gov (United States)

    Sauls, J. A.; Mizushima, Takeshi

    2017-03-01

    Superfluid 3He is a spin-triplet (S =1 ), p -wave (L =1 ) BCS condensate of Cooper pairs with total angular momentum J =0 in the ground state. In addition to the breaking of U(1) gauge symmetry, separate spin or orbital rotation symmetry is broken to the maximal subgroup SO (3) S×SO (3) L→SO(3 ) J . The fermions acquire mass mF≡Δ , where Δ is the BCS gap. There are also 18 bosonic excitations: 4 Nambu-Goldstone modes and 14 massive amplitude Higgs modes. The bosonic modes are labeled by the total angular momentum J ∈{0 ,1 ,2 } , and parity under particle-hole symmetry c =±1 . For each pair of angular momentum quantum numbers J ,Jz , there are two bosonic partners with c =±1 . Based on this spectrum, Nambu proposed a sum rule connecting the fermion and boson masses for BCS-type theories, which for 3He-B is MJ,+ 2+MJ,- 2=4 mF2 for each family of bosonic modes labeled by J , where MJ ,c is the mass of the bosonic mode with quantum numbers (J ,c ) . The Nambu sum rule (NSR) has recently been discussed in the context of Nambu-Jona-Lasinio models for physics beyond the standard model to speculate on possible partners to the recently discovered Higgs boson at higher energies. Here, we point out that the Nambu fermion-boson mass relations are not exact. Corrections to the bosonic masses from (i) leading-order strong-coupling corrections to BCS theory, and (ii) polarization of the parent fermionic vacuum lead to violations of the sum rule. Results for these mass corrections are given in both the T →0 and T →Tc limits. We also discuss experimental results, and theoretical analysis, for the masses of the Jc=2± Higgs modes and the magnitude of the violation of the NSR.

  2. High performance manned interplanetary space vehicle using D-3He Inertial Electrostatic Fusion

    Science.gov (United States)

    Burton, R.; Momota, H.; Richardson, N.; Coventry, M.; Shaban, Y.; Miley, G. H.

    2002-01-01

    A preliminary system design is presented for a high performance 100 MWe manned space vehicle in the 500 metric ton class, based on Inertial Electrostatic Fusion (IEC), with trip times to the outer planets of several months. An IEC is chosen because it simplifies structure results in a very high power to weight ratio. The fusion reactor uses D-3He fuel which generates 14.7-MeV protons as the primary reaction product. The propulsion system design philosophy is based on direct conversion of proton energy to electricity, avoiding the thermalization of the working fluid to maximize efficiency. The principle system components of crew compartment, electronics, fusion reactor, traveling wave direct energy converter, step-down transformer, rectifier, ion thruster and heat rejection radiators are described. The design requires that an IEC reactor with a proton energy gain (power in 14.7-MeV protons/input electric power) of 4 or better is necessary to keep radiator mass and size at acceptable levels. Extrapolation of present laboratory scale IEC experiments to reactor relevant conditions is possible theoretically, but faces several open issues including stability under high-density conditions. Since unburned fusion fuels are recycled rather than exhausted with the propellant, problems of fuel weight and preservation of 3He are minimized. The 100-MWe propulsion system is based on NSTAR-extrapolated krypton ion thrusters operating at a specific impulse of 16,000 seconds and a total thrust of 1020 N. Thrust time for a typical outer planet mission ΔV of 50,000 m/s is then ~200 days. .

  3. Distinguishing 3He and 4He with the Electron Proton Telescope (EPT) on Solar Orbiter

    Science.gov (United States)

    Boden, S.; Kulkarni, S. R.; Steinhagen, J.; Tammen, J.; Martin-Garcia, C.; Wimmer-Schweingruber, R. F.; Boettcher, S. I.; Seimetz, L.; Ravanbakhsh, A.; Elftmann, R.; Schuster, B.; Kulemzin, A.; Kolbe, S.; Mahesh, Y.; Knieriem, V.; Yu, J.; Kohler, J.; Panitzsch, L.; Terasa, C.; Boehm, E.; Rodriguez-Pacheco, J.; Prieto, M.; Gomez-Herrero, R.

    2015-12-01

    The Electron Proton Telescope (EPT) is one of the sensors of the Energetic Particle Detector (EPD) for the Solar Orbiter mission, which will provide key measurements to address particle acceleration at and near the Sun. The EPD suite consists of four different sensors (STEP, SIS, EPT and HET) which together will resolve the energetic particle spectrum from 2 keV to 20 MeV for electrons, 3 keV to 100 MeV for protons and circa 100 keV/nuc to 100 MeV/nuc for heavier ions.EPT itself is primarily designed to cleanly separate and measure electrons in the energy range from 20 - 400 keV and protons from 20 - 7000 keV. To achieve this, EPT uses two back-to-back solid state detectors with a magnet system to deflect electrons on one side and a Polyimide foil to stop protons below ~400 keV on the other side. The two detectors then serve as each other's anti-coincidence. Additionally this setup also allows us to measure penetrating particles with deposited energies in the 1 MeV to 40 MeV range. Looking at the ratio of deposited energy in the two detectors versus total deposited energy allows us to differentiate between protons and alpha particles. Distinguishing 3He from 4He will be challenging, but possible provided good knowledge of the instrument, high-fidelity modeling and a precise calibration of EPT. Here, we will present feasibility studies leading to a determination of the 3He / 4He ratio with EPT.

  4. Novel and efficient {sup 10}B lined tubelet detector as a replacement for {sup 3}He neutron proportional counters

    Energy Technology Data Exchange (ETDEWEB)

    Tsorbatzoglou, Kyriakos [Centronic LLC, 16203 Park Row, Houston, TX 77084 (United States); McKeag, Robert D., E-mail: info@centronic.us [Centronic Limited, Centronic House, King Henry' s Drive, Croydon CR9 0BG (United Kingdom)

    2011-10-01

    This paper presents a novel and robust proportional detector which addresses the well publicized shortage of {sup 3}He gas by using a {sup 10}B lining applied to a tubelet configuration. The advantage of the tubelet structure is that it yields a detector maintaining the form factor of a conventional {sup 3}He tube whilst achieving a sensitivity of up to 75% of a 3 atm {sup 3}He device. The design and fabrication of the tubelet detector is presented and discussed with test data comparing the new detector to existing {sup 3}He and BF{sub 3} tubes. The application of the tubelet design to security and industrial applications including retro-fitting to existing portals and suitability for high integrity oil and gas installations is addressed.

  5. Search for the K−pp bound state via the in-flight 3He(K−, n reaction

    Directory of Open Access Journals (Sweden)

    Sada Y.

    2014-01-01

    Full Text Available In the J-PARC E15 experiment, a K− pp search was performed via the 3He(K−, n reaction at 1.0 GeV/c. A forward-going neutron is detected by a neutron counter with 15 m flight length, and decay particles from K− pp are simultaneously measured by a cylindrical detector system that surrounds a liquid 3He target system. In March and May, 2013, we carried out the first physics data-taking with 5×109 incident kaons on the 3He target, and we have obtained a preliminary exclusive analysis result of 3He(K−, Λpn reaction.

  6. Dating of Quaternary basalts using the cosmogenic 3He and 14C methods with implications for excess 40Ar

    Science.gov (United States)

    Laughlin, A. William; Poths, Jane; Healey, Heather A.; Reneau, Steven; Woldegabriel, Giday

    1994-02-01

    Concordant radiocarbon and cosmogenic 3He dates of 3 and 11 ka on basalt flows and associated scoria deposits from the Zuni-Bandera volcanic field in New Mexico further substantiate published production rates and latitudinal and altitudinal corrections for 3He. Identical 3He concentrations in coexisting olivine and clinopyroxene confirm that these two minerals have very similar production rates. A cosmogenic 3He date of 57 ka on another flow is concordant with a U-series date and is younger than two K-Ar dates, suggesting that this flow contains excess 40Ar. This excess 40Ar is also evident in gases released by vacuum crushing of olivine-clinopyroxene fractions from all three flows.

  7. Isospin effects in the exclusive dp → {sup 3}He π{sup +}π{sup -} reaction

    Energy Technology Data Exchange (ETDEWEB)

    Mielke, M.; Burmeister, I.; Fritzsch, C.; Goslawski, P.; Khoukaz, A.; Mersmann, T.; Papenbrock, M.; Rausmann, T.; Taeschner, A. [Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Chiladze, D. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Centre for Hadron Physics, Juelich (Germany); Tbilisi State University, High Energy Physics Institute, Tbilisi (Georgia); Dymov, S. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Centre for Hadron Physics, Juelich (Germany); JINR, Laboratory of Nuclear Problems, Dubna (Russian Federation); Gebel, R.; Hartmann, M.; Kacharava, A.; Lorentz, B.; Ohm, H.; Serdyuk, V.; Stroeher, H. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Centre for Hadron Physics, Juelich (Germany); Kulessa, P. [H. Niewodniczanski Institute of Nuclear Physics PAN, Cracow (Poland); Mikirtychiants, S. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Centre for Hadron Physics, Juelich (Germany); Petersburg Nuclear Physics Institute, High Energy Physics Department, Gatchina (Russian Federation); Valdau, Yu. [Petersburg Nuclear Physics Institute, High Energy Physics Department, Gatchina (Russian Federation); Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Wilkin, C. [UCL, Physics and Astronomy Department, London (United Kingdom)

    2014-06-15

    The differential cross section for the exclusive dp → {sup 3}He π{sup +}π{sup -} reaction has been measured with high resolution and large statistics over a large fraction of the backward {sup 3}He hemisphere at the excess energy 265 MeV using the COSY-ANKE magnetic spectrometer. Though the well-known ABC enhancement is observed in the π{sup +}π{sup -} spectrum, the differences detected between the π{sup +3}He and π{sup -3}He invariant-mass distributions show that there must be some isospin-one π π production even at relatively low excess energies. The invariant-mass differences are modeled in terms of the sequential decay N*(1440) → Δ(1232)π → Nππ. (orig.)

  8. Observation of the n(^3He,t)p Reaction by Detection of Far-Ultraviolet Radiation

    Science.gov (United States)

    Clark, Charles W.; Thompson, Alan K.; Coplan, Michael A.; Cooper, John W.; Hughes, Patrick; Vest, Robert E.

    2008-03-01

    We have detected Lyman alpha radiation as a product of the n(^3 He,t)p nuclear reaction, induced in a ^3He gas cell irradiated by a cold neutron beam at the NIST Center for Neutron Research. The predominant source of this radiation appears to be decay of the 2p state of tritium produced by charge transfer and excitation collisions with the background ^3He gas. For atmospheric pressure and room temperature in the ^3He cell, we find yields of tens of Lyman alpha photons for every neutron reaction. These results suggest a method of cold neutron detection that is complementary to existing technologies that use proportional counters. In particular, this approach may provide single neutron sensitivity with wide dynamic range capability, and a class of neutron detectors that are compact and operate at relatively low voltages.

  9. Application of a portable 3He-based polarization insert at a time-of-flight neutron reflectometer

    Science.gov (United States)

    Kreuzpaintner, Wolfgang; Masalovich, Sergey; Moulin, Jean-François; Wiedemann, Birgit; Ye, Jingfan; Mayr, Sina; Paul, Amitesh; Haese, Martin; Pomm, Matthias; Böni, Peter

    2017-03-01

    The suitability of a transportable 3He-spin filter as temporary broadband polarizer for a Time-of-Flight neutron reflectometer is demonstrated. A simple two-wavelength method for characterisation of a 3He-spin filter is proposed, which can be applied even if the absolute transmittance of the 3He-spin filter cannot be accurately determined. We demonstrate the data treatment procedure for extracting the spin-up and spin-down neutron reflectivity from measurements obtained with a time dependent 3He polarization. The extraction of a very weak magnetic signal from reflectivity data, measured on the in-situ grown magnetic heterostructure Fe1nm /Cu20nm /Sisubstrate in an externally applied magnetic field of 30 mT is presented and compared to similar measurements on the growth stage Cu20nm /Sisubstrate of the very same sample, which does not yet contain any magnetic material.

  10. Hyperpolarized {sup 3}He magnetic resonance imaging: Preliminary evaluation of phenotyping potential in chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, Lindsay, E-mail: lmathew@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Department of Medical Biophysics, University of Western Ontario, London (Canada); Kirby, Miranda, E-mail: mkirby@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Department of Medical Biophysics, University of Western Ontario, London (Canada); Etemad-Rezai, Roya, E-mail: Roya.EtemadRezai@lhsc.on.ca [Department of Medical Imaging, University of Western Ontario (Canada); Wheatley, Andrew, E-mail: awheat@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); McCormack, David G., E-mail: David.McCormack@lhsc.on.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Division of Respirology, Department of Medicine, University of Western Ontario, London (Canada); Lawson Health Research Institute, London (Canada); Parraga, Grace, E-mail: gep@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Department of Medical Biophysics, University of Western Ontario, London (Canada); Department of Medical Imaging, University of Western Ontario (Canada); Lawson Health Research Institute, London (Canada)

    2011-07-15

    Rationale and objectives: Emphysema and small airway obstruction are the pathological hallmarks of chronic obstructive pulmonary disease (COPD). The aim of this pilot study in a small group of chronic obstructive pulmonary disease (COPD) patients was to quantify hyperpolarized helium-3 ({sup 3}He) magnetic resonance imaging (MRI) functional and structural measurements and to explore the potential role for {sup 3}He MRI in detecting the lung structural and functional COPD phenotypes. Materials and methods: We evaluated 20 ex-smokers with stage I (n = 1), stage II (n = 9) and stage III COPD (n = 10). All subjects underwent same-day plethysmography, spirometry, {sup 1}H MRI and hyperpolarized {sup 3}He MRI at 3.0 T. {sup 3}He ventilation defect percent (VDP) was generated from {sup 3}He static ventilation images and {sup 1}H thoracic images and the {sup 3}He apparent diffusion coefficient (ADC) was derived from diffusion-weighted MRI. Results: Based on the relative contribution of normalized ADC and VDP, there was evidence of a predominant {sup 3}He MRI measurement in seven patients (n = 3 mainly ventilation defects or VDP dominant (VD), n = 4 mainly increased ADC or ADC dominant (AD)). Analysis of variance (ANOVA) showed significantly lower ADC for subjects with predominantly elevated VDP (p = 0.02 compared to subjects with predominantly elevated ADC; p = 0.008 compared to mixed group) and significantly decreased VDP for subjects with predominantly elevated ADC (p = 0.003, compared to mixed group). Conclusion: In this small pilot study, a preliminary analysis shows the potential for {sup 3}He MRI to categorize or phenotype COPD ex-smokers, providing good evidence of feasibility for larger prospective studies.

  11. Assessing the use of 3H-3He dating to determine the subsurface transit time of cave drip waters.

    Science.gov (United States)

    Kluge, Tobias; Wieser, Martin; Aeschbach-Hertig, Werner

    2010-09-01

    (3)H-(3)He measurements constitute a well-established method for the determination of the residence time of young groundwater. However, this method has rarely been applied to karstified aquifers and in particular to drip water in caves, despite the importance of the information which may be obtained. Besides the determination of transfer times of climate signals from the atmosphere through the epikarst to speleothems as climate archives, (3)H-(3)He together with Ne, Ar, Kr, Xe data may also help to give new insights into the local hydrogeology, e.g. the possible existence of a perched aquifer above a cave. In order to check the applicability of (3)H-(3)He dating to cave drips, we collected drip water samples from three adjacent caves in northwestern Germany during several campaigns. The noble gas data were evaluated by inverse modelling to obtain recharge temperature and excess air, supporting the calculation of the tritiogenic (3)He and hence the (3)H-(3)He age. Although atmospheric noble gases were often found to be close to equilibrium with the cave atmosphere, several drip water samples yielded an elevated (3)He/(4)He ratio, providing evidence for the accumulation of (3)He from the decay of (3)H. No significant contribution of radiogenic (4)He was found, corresponding to the low residence times mostly in the range of one to three years. Despite complications during sampling, conditions of a perched aquifer could be confirmed by replicate samples at one drip site. Here, the excess air indicator ΔNe was about 10 %, comparable to typical values found in aquifers in mid-latitudes. The mean (3)H-(3)He age of 2.1 years at this site presumably refers to the residence time in the perched aquifer and is lower than the entire transit time of 3.4 years estimated from the tritium data.

  12. {gamma} decay of spin-isospin states in {sup 13}N via ({sup 3}He, t{gamma}) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ihara, F.; Akimune, H.; Daito, I.; Fujimura, H.; Fujiwara, M.; Inomata, T.; Ishibashi, K.; Yoshida, H. [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics; Fujita, Y.

    1998-03-01

    Spin-isospin states in {sup 13}N have been studied by means of the {sup 13}C ({sup 3}He,t) reaction at and near zero degree, at E({sup 3}He)=450 MeV. Decayed {gamma}-rays from each state were measured at backward angle in coincidence with the ejectile tritons. The branching ratio of {gamma} decay for some of spin-isospin states were determined and were compared to those from previous data. (author)

  13. Magnetic control of ultra-cold $^6$Li and $^{174}$Yb($^3P_2$) atom mixtures with Feshbach resonances

    CERN Document Server

    Petrov, Alexander; Kotochigova, Svetlana

    2015-01-01

    We theoretically evaluate the feasibility to form magnetically-tunable Feshbach molecules in collisions between fermionic $^6$Li atoms and bosonic metastable $^{174}$Yb($^3$P$_2$) atoms. In contrast to the well-studied alkali-metal atom collisions, collisions with meta-stable atoms are highly anisotropic. Our first-principle coupled-channel calculation of these collisions reveals the existence of broad Feshbach resonances due to the combined effect of anisotropic-molecular and atomic-hyperfine interactions. In order to fit our predictions to the specific positions of experimentally-observed broad resonance structures \\cite{Deep2015} we optimized the shape of the short-range potentials by direct least-square fitting. This allowed us to identify the dominant resonance by its leading angular momentum quantum numbers and describe the role of collisional anisotropy in the creation and broadening of this and other resonances.

  14. Characterization of charge-exchange collisions between ultracold $\\rm{^6Li}$ atoms and $\\rm{^{40}Ca^+}$ ions

    CERN Document Server

    Saito, R; Sasakawa, M; Nakai, R; Raoult, M; Silva, H Da; Dulieu, O; Mukaiyama, T

    2016-01-01

    We investigate the energy dependence and the internal-state dependence of the charge-exchange collision cross sections in a mixture of $^6$Li atoms and $^{40}$Ca$^+$ ions in the collision energy range from 0.2 mK to 1 K. Deliberately excited ion micromotion is used to control the collision energy of atoms and ions. The energy dependence of the charge-exchange collision cross section obeys the Langevin model in the temperature range of the current experiment, and the measured magnitude of the cross section is correlated to the internal state of the $^{40}$Ca$^+$ ions. Revealing the relationship between the charge-exchange collision cross sections and the interaction potentials is an important step toward the realization of the full quantum control of the chemical reactions at an ultralow temperature regime.

  15. Nuclear structure with accurate chiral perturbation theory nucleon-nucleon potential: Application to 6Li and 10B

    Energy Technology Data Exchange (ETDEWEB)

    Navratil, P; Caurier, E

    2003-10-14

    The authors calculate properties of A = 6 system using the accurate charge-dependent nucleon-nucleon (NN) potential at fourth order of chiral perturbation theory. By application of the ab initio no-core shell model (NCSM) and a variational calculation in the harmonic oscillator basis with basis size up to 16 {h_bar}{Omega} they obtain the {sup 6}Li binding energy of 28.5(5) MeV and a converged excitation spectrum. Also, they calculate properties of {sup 10}B using the same NN potential in a basis space of up to 8 {h_bar}{Omega}. The results are consistent with results obtained by standard accurate NN potentials and demonstrate a deficiency of Hamiltonians consisting of only two-body terms. At this order of chiral perturbation theory three-body terms appear. It is expected that inclusion of such terms in the Hamiltonian will improve agreement with experiment.

  16. Collective modes and sound propagation in a magnetic field in superfluid3He-B

    Science.gov (United States)

    Shivaram, B. S.; Meisel, M. W.; Sarma, Bimal K.; Halperin, W. P.; Ketterson, J. B.

    1986-04-01

    A high-resolution, ultrasonic (12 89 MHz) acoustic impedance technique has been used to investigate the order parameter collective modes in superfluid3He-B over a pressure range of 0 15 bar and in magnetic fields up to 180 mT. In agreement with earlier experiments, the J=2 real squashing mode has been observed to split into five components in small magnetic fields. However, contrary to earlier theoretical estimates, the Zeeman shifts have been found to become extremely nonlinear as the magnetic field is increased. The extent of this nonlinearity is largest at low pressures and at temperatures close to T c. In comparison with recent theoretical work, the nonlinear Zeeman shifts may be explained as a result of two effects. First, there is a significant distortion of the B-phase energy gap in large magnetic fields. Second, there is an important coupling between the same J zsubstates of the different J modes. In this sense the nonlinear evolution of the real squashing mode constitutes the observation of the Paschen-Back effect in3He-B. A comparison of the observed Zeeman shifts with theoretical expressions has yielded information about particle-particle and particle-hole interaction effects in the superfluid. In the limit T → 0 and above a threshold field, the real squashing mode has been found to possess additional structure. The J z=0 substate has been observed to split into a doublet. The separation between the two components of the doublet is of the order of 100 200 kHz and remains independent of the magnetic field. The origin of the doublet may be understood in terms of a recent theory which postulates a texture-dependent collective mode frequency. Further, at extremely small fields the effects due to dispersion of the real squashing modes have been found to be important. The magnitude of the dispersion-induced mode splitting in zero field is found to be consistent with theoretical predictions. The J=2 squashing mode has also been studied in the presence of a

  17. Particle transport in 3He-rich events: wave-particle interactions and particle anisotropy measurements

    Directory of Open Access Journals (Sweden)

    T. Hada

    Full Text Available Energetic particles and MHD waves are studied using simultaneous ISEE-3 data to investigate particle propagation and scattering between the source near the Sun and 1 AU. 3 He-rich events are of particular interest because they are typically low intensity "scatter-free" events. The largest solar proton events are of interest because they have been postulated to generate their own waves through beam instabilities. For 3 He-rich events, simultaneous interplanetary magnetic spectra are measured. The intensity of the interplanetary "fossil" turbulence through which the particles have traversed is found to be at the "quiet" to "intermediate" level of IMF activity. Pitch angle scattering rates and the corresponding particle mean free paths lW - P are calculated using the measured wave intensities, polarizations, and k directions. The values of lW - P are found to be ~ 5 times less than the value of lHe , the latter derived from He intensity and anisotropy time profiles. It is demonstrated by computer simulation that scattering rates through a 90° pitch angle are lower than that of other pitch angles, and that this is a possible explanation for the discrepancy between the lW - P and lHe values. At this time the scattering mechanism(s is unknown. We suggest a means where a direct comparison between the two l values could be made. Computer simulations indicate that although scattering through 90° is lower, it still occurs. Possibilities are either large pitch angle scattering through resonant interactions, or particle mirroring off of field compression regions. The largest solar proton events are analyzed to investigate the possibilities of local wave generation at 1 AU. In accordance with the results of a previous calculation (Gary et al., 1985 of beam stability, proton beams at 1 AU are found to be marginally stable. No evidence for substantial wave amplitude was found. Locally generated waves, if present, were less than 10-3 nT 2 Hz-1 at the leading

  18. Breakup Coupling Effects on Near-Barrier {sup 6}Li, {sup 7}Be and {sup 8}B + {sup 58}Ni Elastic Scattering Compared

    Energy Technology Data Exchange (ETDEWEB)

    Keeley, N. [Department of Nuclear Reactions, Andrzej Soltan Institute for Nuclear Studies, ul. Hoza 69, 00-681 Warsaw (Poland); Mackintosh, R.S. [Department of Physics and Astronomy, Open University, Milton Keynes, MK7 6AA (United Kingdom); Beck, C. [Institut Pluridisciplinaire Hubert Curien et Universite Louis Pasteur, Boite Postale 28, F-67037 Strasbourg Cedex 2 (France)

    2010-03-01

    New data for near-barrier {sup 6}Li, {sup 7}Be and {sup 8}B + {sup 58}Ni elastic scattering enable a comparison of breakup coupling effects for these loosely-bound projectiles. Coupled Discretised Continuum Channels (CDCC) calculations suggest that the large total reaction cross sections for {sup 8}B + {sup 58}Ni are dominated by breakup at near-barrier energies, unlike {sup 6}Li and {sup 7}Be where breakup makes a small contribution. In spite of this, the CDCC calculations show a small coupling influence due to breakup for {sup 8}B, in contrast to the situation for {sup 6}Li and {sup 7}Be. An examination of the S matrices gives a clue to this counter-intuitive behaviour.

  19. Search for eta-mesic 4He in the dd->3He n pi0 and dd->3He p pi- reactions with the WASA-at-COSY facility

    CERN Document Server

    Adlarson, P; Bardan, W; Bashkanov, M; Bergmann, F S; Berlowski, M; Bhatt, H; Bondar, A; Buescher, 9 M; Calen, H; Ciepal, I; Clement, H; Czerwinski, E; Demmich, K; Engels, R; Erven, A; Erven, W; Eyrich, W; Fedorets, P; Foehl, K; Fransson, K; Goldenbaum, F; Goswami, A; Grigoryev, K; Gullstroem, C -O; Heijkenskjoeld, L; Hejny, V; Huesken, N; Jarczyk, L; Johansson, T; Kamys, B; Kelkar, N G; Kemmerling, G; Khatri, G; Khoukaz, A; Khreptak, O; Kirillov, D A; Kistryn, S; Kleines, H; Klos, B; Krzemien, W; Kulessa, P; Kupsc, A; Kuzmin, A; Lalwani, K; Lersch, D; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Marianski, B; Morsch, H -P; Moskal, P; Ohm, H; del Rio, E Perez; Piskunov, N M; Prasuhn, D; Pszczel, D; Pysz, K; Pyszniak, A; Ritman, J; Roy, A; Rudy, Z; Rundel, O; Sawant, S; Schadmand, S; Schaetti-Ozerianska, I; Sefzick, T; Serdyuk, V; Shwartz, B; Sitterberg, K; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Stephan, E; Sterzenbach, G; Stockhorst, H; Stroeher, H; Szczurek, A; Trzcinski, A; Varma, R; Wolke, M; Wronska, A; Wuestner, P; Yamamoto, A; Zabierowski, J; Zielinski, M J; Zlomanczuk, J; Zupranski, P; Zurek, M

    2016-01-01

    The search for 4He-eta bound states was performed with the WASA-at-COSY facility via the measurement of the excitation function for the dd->3He n pi0 and dd->3He p pi- processes. The beam momentum was varied continuously between 2.127 GeV/c and 2.422 GeV/c, corresponding to the excess energy for the dd->4He eta reaction ranging from Q=-70 MeV to Q=30 MeV. The luminosity was determined based on the dd->3He n reaction and quasi-free proton-proton scattering via dd->pp n_spectator n_spectator reactions. The excitation functions determined independently for the measured reactions do not reveal a structure which could be interpreted as a narrow mesic nucleus. Therefore, the upper limits of the total cross sections for the bound state production and decay in dd->(4He-eta)_bound->3He n pi0 and dd->(4He-eta)_bound->3He p pi- processes were determined taking into account the isospin relation between both the channels considered. The results of the analysis depend on the assumptions of the N* momentum distribution in t...

  20. 3H/3He ages, CFC ages and He isotopes in the fractured bedrock of the Mirror Lake Basin, NH

    Science.gov (United States)

    Torgersen, T.; Stute, M.; Drenkard, S.; Schlosser, P.; Busenberg, E.; Plummer, N.; Shapiro, A.

    2001-05-01

    Tritium/3He and CFC (chlorofluorocarbon) analyses were conducted on groundwater samples from the fractured bedrock and the overlying drift of Mirror Lake watershed in central New Hampshire. These groundwaters have a significant terrigenic helium component that increases with depth. The 3He/4He ratio of the terrigenic helium indicates the presence of two groundwater types. Where terrigenic sources of 3He are no more than 10 times the 3He signal produced by 3H decay (tritiogenic 3He), 3H/3He ages can be calculated. However, drift age profiles cannot be interpreted as recharge rates because the 2D, 2-layer coupled bedrock/drift system violates the simple homogeneous 1D conditions necessary to interpret age profiles as recharge rates. Secondly, while some agreement is seen between 3H/3He ages and CFC ages, the reconstruction of the 1963 'bomb' 3H peak yields a maximum that is significantly less (1/10) than expected. This apparent loss of 3H is cannot be attributed to dispersion or dual hydraulic conductivity but is consistent with the models of dual porosity. The data also demonstrate that '3H/3Hetri calibrated 4He ages' are invalid and cannot be used to extend the 'age' information contained in He isotope analysis. The results of this study again demonstrate that tracers have an important role in the calibration and definition of flow models for complex groundwater systems. However, it is suggested that tracers should be routinely inserted into groundwater flow models to determine (I) which tracers are best suited to the problem and (ii) where to sample for tracers to best differentiate among model possibilities as well as which parameters constitute the best descriptions of the groundwater system. Such coupling of multiple tracers and flow models at the earliest stages will provide the highest probability for determining the best flow model.

  1. A method for investigation of the D({sup 4}He, γ){sup 6}Li reaction in the Ultralow energy region under a high background

    Energy Technology Data Exchange (ETDEWEB)

    Bystritsky, V.M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Dudkin, G.N. [National Research Tomsk Polytechnic University, Tomsk (Russian Federation); Krylov, A.R. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Gazi, S.; Huran, J. [Institute of Electrical Engineering, Slovak Academy of Sciences, Bratislava (Slovakia); Nechaev, B.A.; Padalko, V.N. [National Research Tomsk Polytechnic University, Tomsk (Russian Federation); Sadovsky, A.B. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Tuleushev, Yu.Zh. [Institute of Nuclear Physics, Ministry of Power Engineering, Almaty (Kazakhstan); Filipowicz, M. [Faculty of Energy and Fuels, University of Science and Technologies, Krakow (Poland); Philippov, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2016-07-21

    The cosmological lithium problem, that is, a noticeable discrepancy between the predicted and observed abundances of lithium, is in conflict with the Standard Big Bang Nucleosynthesis model. For example, the abundance of {sup 7}Li is 2–4 times smaller than predicted by the Standard Big Bang Nucleosynthesis. As to the abundance of {sup 6}Li, recent more accurate optical investigations have yielded only the upper limit on the {sup 6}Li/{sup 7}Li ratio, which makes the problem of {sup 6}Li abundance and accordingly of disagreement with the Standard Big Bang Nucleosynthesis predictions less acute. However, experimental study of the D({sup 4}He, γ){sup 6}Li reaction cross section is still of current importance because there is a theoretical approach predicting its anomalously large value in the region of energies below the Standard Big Bang Nucleosynthesis energy. The work is dedicated to the measurement of the cross section for the D({sup 4}He, γ){sup 6}Li reaction proceeding in zirconium deuteride at the incident {sup 4}He{sup +}ion energy of 36 keV. The experiment is performed at a pulsed Hall plasma accelerator with an energy spread of 20% FWHM. A method for direct measurement of the background from the reaction chain D({sup 4}He, {sup 4}He)D→D(D, n){sup 3}He→(n, γ) and/or (n, n′γ) ending with activation of the surrounding material by neutrons is proposed and implemented in the work. An upper limit on the D({sup 4}He, γ){sup 6}Li reaction cross section σ≤7·10{sup −36} cm{sup 2} at the 90% confidence level is obtained.

  2. A method for investigation of the D(4He, γ)6Li reaction in the Ultralow energy region under a high background

    Science.gov (United States)

    Bystritsky, V. M.; Dudkin, G. N.; Krylov, A. R.; Gazi, S.; Huran, J.; Nechaev, B. A.; Padalko, V. N.; Sadovsky, A. B.; Tuleushev, Yu. Zh.; Filipowicz, M.; Philippov, A. V.

    2016-07-01

    The cosmological lithium problem, that is, a noticeable discrepancy between the predicted and observed abundances of lithium, is in conflict with the Standard Big Bang Nucleosynthesis model. For example, the abundance of 7Li is 2-4 times smaller than predicted by the Standard Big Bang Nucleosynthesis. As to the abundance of 6Li, recent more accurate optical investigations have yielded only the upper limit on the 6Li/7Li ratio, which makes the problem of 6Li abundance and accordingly of disagreement with the Standard Big Bang Nucleosynthesis predictions less acute. However, experimental study of the D(4He, γ)6Li reaction cross section is still of current importance because there is a theoretical approach predicting its anomalously large value in the region of energies below the Standard Big Bang Nucleosynthesis energy. The work is dedicated to the measurement of the cross section for the D(4He, γ)6Li reaction proceeding in zirconium deuteride at the incident 4He+ion energy of 36 keV. The experiment is performed at a pulsed Hall plasma accelerator with an energy spread of 20% FWHM. A method for direct measurement of the background from the reaction chain D(4He, 4He)D→D(D, n)3He→(n, γ) and/or (n, n‧γ) ending with activation of the surrounding material by neutrons is proposed and implemented in the work. An upper limit on the D(4He, γ)6Li reaction cross section σ≤7·10-36 cm2 at the 90% confidence level is obtained.

  3. The injection of ten electron/$^{3}$He-rich SEP events

    CERN Document Server

    Wang, Linghua; Mason, Glenn M; Lin, Robert P; Li, Gang

    2016-01-01

    We have derived the particle injections at the Sun for ten good electron/$^{3}$He-rich solar energetic particle (SEP) events, using a 1.2 AU particle path length (suggested by analysis of the velocity dispersion). The inferred solar injections of high-energy ($\\sim$10 to 300 keV) electrons and of $\\sim$MeV/nucleon ions (carbon and heavier) start with a delay of 17$\\pm$3 minutes and 75$\\pm$14 minutes, respectively, after the injection of low-energy ($\\sim$0.4 to 9 keV) electrons. The injection duration (averaged over energy) ranges from $\\sim$200 to 550 minutes for ions, from $\\sim$90 to 160 minutes for low-energy electrons, and from $\\sim$10 to 30 minutes for high-energy electrons. Most of the selected events have no reported H$\\alpha$ flares or GOES SXR bursts, but all have type III radio bursts that typically start after the onset of a low-energy electron injection. All nine events with SOHO/LASCO coverage have a relatively fast ($>$570km/s), mostly narrow ($\\lesssim$30$^{\\circ}$), west-limb coronal mass ej...

  4. SQUID measurements of remanent magnetisation in refillable 3He spin-filter cells (SFC)

    Science.gov (United States)

    Hutanu, V.; Rupp, A.; Sander-Thömmes, T.

    2007-07-01

    A strong influence of external magnetic fields on the relaxation time constant T1 of glass cells serving as reservoirs for polarised 3He, observed for various alkali metal-coated cells made of different glass types, was initially associated with the presence of a large number of ferromagnetic clusters on the glass surface. Later experiments showed the presence of the so-called “ T1 hysteresis” phenomenon with a similar distinctiveness also in uncoated cells made of pure synthetic quartz glass. It suggests that the origin of such a relaxation is a macroscopic magnetisation in the bulk of the cell. We present the results of a multi-SQUID system investigation on magnetised and non-magnetised quartz glass cells, Cs coated as well as bare wall, to be used as neutron spin filters at HMI Berlin. The presence of a macroscopic remanent magnetic moment in the cells after their exposition to external magnetic fields has been experimentally shown. More than 80% of the remanent magnetic moment of the magnetised cells was found to be concentrated in the region of the glass valves. SQUID measurements reveal the existence of some remanent magnetisation in all valve parts and also in the vacuum grease, but most magnetic are the plastic parts and the O-ring. Different valve and sealing types have been compared in order to find the less magnetisable one.

  5. SQUID measurements of remanent magnetisation in refillable {sup 3}He spin-filter cells (SFC)

    Energy Technology Data Exchange (ETDEWEB)

    Hutanu, V. [Hahn-Meitner-Institut Berlin, Department SF2, Glienicker Str. 100, D-14109 Berlin (Germany)]. E-mail: vladimir.hutanu@frm2.tum.de; Rupp, A. [Hahn-Meitner-Institut Berlin, Department SF2, Glienicker Str. 100, D-14109 Berlin (Germany); Sander-Thoemmes, T. [Physikalisch-Technische Bundesanstalt, Abbestr. 10-12, D-10587 Berlin (Germany)

    2007-07-15

    A strong influence of external magnetic fields on the relaxation time constant T {sub 1} of glass cells serving as reservoirs for polarised {sup 3}He, observed for various alkali metal-coated cells made of different glass types, was initially associated with the presence of a large number of ferromagnetic clusters on the glass surface. Later experiments showed the presence of the so-called 'T {sub 1} hysteresis' phenomenon with a similar distinctiveness also in uncoated cells made of pure synthetic quartz glass. It suggests that the origin of such a relaxation is a macroscopic magnetisation in the bulk of the cell. We present the results of a multi-SQUID system investigation on magnetised and non-magnetised quartz glass cells, Cs coated as well as bare wall, to be used as neutron spin filters at HMI Berlin. The presence of a macroscopic remanent magnetic moment in the cells after their exposition to external magnetic fields has been experimentally shown. More than 80% of the remanent magnetic moment of the magnetised cells was found to be concentrated in the region of the glass valves. SQUID measurements reveal the existence of some remanent magnetisation in all valve parts and also in the vacuum grease, but most magnetic are the plastic parts and the O-ring. Different valve and sealing types have been compared in order to find the less magnetisable one.

  6. Response Matrix of a Bonner Spheres Spectrometer with {sup 3} He Detector

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M. [Unidades Academicas de Estudios Nucleares, Ing. Electrica y Matematicas, Universidad Autonoma de Zacatecas, Apdo. Postal 336, 98000 Zacatecas (Mexico)]. e-mail: rvega@cantera.reduaz.mx

    2004-07-01

    Using MCNP code the response matrix of a Bonner spheres spectrometer was calculated. The spectrometer has a 3.2 cm-diameter thermal neutron detector; this is a {sup 3} He-filled proportional counter that is located at the center of a set of polyethylene spheres. The response was calculated for 0, 3, 5, 6, 8, 10, 12 and 16 inches-diameter polyethylene spheres for neutrons whose energy goes from 10-9 to 20 MeV. The response matrix was compared with a set of responses measured with several monoenergetic neutron sources, from this comparison calculated matrix is in agreement with the experimental results. Also this matrix was compared against the response matrix calculated for the PTB C spectrometer, Nevertheless that calculation was carried out using a detailed model to describe the proportional counter both matrices were in agreement, small differences are observed in the bare case because the difference in the model used during calculations. Other differences are in some spheres for 14.8 and 20 MeV neutrons probable due to the differences in the cross sections used during both calculations. (Author)

  7. An array of low-background 3He proportional counters for theSudbury Neutrino Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Amsbaugh, J.F.; Anaya, J.M.; Banar, J.; Bowles, T.J.; Browne,M.C.; Bullard, T.V.; Burritt, T.H.; Cox-Mobrand, G.A.; Dai, X.; H.Deng,X.; Di Marco, M.; Doe, P.J.; Dragowsky, M.R.; Duba, C.A.; Duncan, F.A.; Earle, E.D.; Elliott, S.R.; Esch, E.-I.; Fergani, H.; Formaggio, J.A.; Fowler, M.M.; Franklin, J.E.; Geissbuehler, P.; Germani, J.V.; Goldschmidt, A.; Guillian, E.; Hallin, A.L.; Harper, G.; Harvey, P.J.; Hazama, R.; Heeger, K.M.; Heise, J.; Hime, A.; Howe, M.A.; Huang, M.; Kormos, L.L.; Kraus, C.; Krauss, C.B.; Law, J.; Lawson, I.T.; Lesko,K.T.; Loach, J.C.; Majerus, S.; Manor, J.; McGee, S.; Miknaitis, K.K.S.; Miller, G.G.; Morissette, B.; Myers, A.; Oblath, N.S.; O' Kee, H.M.; Ollerhead, R.W.; Peeters, S.J.M.; Poon, A.W.P.; Prior, G.; Reitzner,S.D.; Rielage, K.; Robertson, R.G.H.; Skensved, P.; Smith, A.R.; Smith,M.W.E.; Steiger, T.D.; Stonehill,L.C.; Thornewell, P.M.; Tolich, N.; VanDevender, B.A.; VanWechel, T.D.; Wall, B.L.; Tseung, H.W.C.; Wendland,J.; West, N.; Wilhelmy, J.B.; Wilkerson, J.F.; Wouters, J.M.

    2007-02-01

    An array of Neutral-Current Detectors (NCDs) has been builtin order to make a unique measurement of the total active ux of solarneutrinos in the Sudbury Neutrino Observatory (SNO). Data in the thirdphase of the SNO experiment were collected between November 2004 andNovember 2006, after the NCD array was added to improve theneutral-current sensitivity of the SNO detector. This array consisted of36 strings of proportional counters lled with a mixture of 3He and CF4gas capable of detecting the neutrons liberated by the neutrino-deuteronneutral current reaction in the D2O, and four strings lled with a mixtureof 4He and CF4 gas for background measurements. The proportional counterdiameter is 5 cm. The total deployed array length was 398 m. The SNO NCDarray is the lowest-radioactivity large array of proportional countersever produced. This article describes the design, construction,deployment, and characterization of the NCD array, discusses theelectronics and data acquisition system, and considers event signaturesand backgrounds.

  8. An array of low-background $^3$He proportional counters for the Sudbury Neutrino Observatory

    CERN Document Server

    Amsbaugh, J F; Banar, J C; Bowles, T J; Browne, M C; Bullard, T V; Burritt, T H; Cox-Mobrand, G A; Dai, X; Deng, H; Di Marco, M; Doe, P J; Dragowsky, M R; Duba, C A; Duncan, F A; Earle, E D; Elliott, S R; Esch, E -I; Fergani, H; Formaggio, J A; Fowler, M M; Franklin, J E; Geissbühler, P; Germani, J V; Goldschmidt, A; Guillian, E; Hallin, A L; Harper, G; Harvey, P J; Hazama, R; Heeger, K M; Heise, J; Hime, A; Howe, M A; Huang, M; Kormos, L L; Kraus, C V; Krauss, C B; Law, J; Lawson, I T; Lesko, K T; Loach, J C; Majerus, S; Manor, J; McGee, S; Miknaitis, K K S; Miller, G G; Morissette, B; Myers, A; Oblath, N S; O'Keeffe, H M; Ollerhead, R W; Peeters, S J M; Poon, A W P; Prior, G; Reitzner, S D; Rielage, K; Robertson, R G H; Skensved, P; Smith, A R; Smith, M W E; Steiger, T D; Stonehill, L C; Thornewell, P M; Tolich, N; VanDevender, B A; Van Wechel, T D; Wall, B L; Tseung, H Wan Chan; Wendland, J; West, N; Wilhelmy, J B; Wilkerson, J F; Wouters, J M

    2007-01-01

    An array of Neutral-Current Detectors (NCDs) has been built in order to make a unique measurement of the total active flux of solar neutrinos in the Sudbury Neutrino Observatory (SNO). Data in the third phase of the SNO experiment were collected between November 2004 and November 2006, after the NCD array was added to improve the neutral-current sensitivity of the SNO detector. This array consisted of 36 strings of proportional counters filled with a mixture of $^3$He and CF$_4$ gas capable of detecting the neutrons liberated by the neutrino-deuteron neutral current reaction in the D$_2$O, and four strings filled with a mixture of $^4$He and CF$_4$ gas for background measurements. The proportional counter diameter is 5 cm. The total deployed array length was 398 m. The SNO NCD array is the lowest-radioactivity large array of proportional counters ever produced. This article describes the design, construction, deployment, and characterization of the NCD array, discusses the electronics and data acquisition sys...

  9. X-rays from antiprotonic sup 3 He and sup 4 He

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M.; Bacher, R.; Bluem, P.; Gotta, D.; Heitlinger, K.; Kunold, W.; Rohmann, D. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Kernphysik Karlsruhe Univ. (T.H.) (Germany, F.R.). Inst. fuer Experimentelle Kernphysik); Egger, J.; Simons, L.M. (Paul Scherrer Inst. (PSI), Villigen (Switzerland)); Elsener, K. (European Organization for Nuclear Research, Geneva (Switzerland))

    1991-02-01

    Antiprotonic X-rays from the helium isotopes have been observed at pressures of 36, 72, 375 and 600 mbar. The antiproton beam from LEAR with momenta of 309 and 202 MeV/c has been stopped at these pressures using the cyclotron trap. The X-rays were detected with Si(Li) and intrinsic Ge semiconductor detectors. Absolute X-ray yields were determined and the strong-interaction 2p shifts and the 2p and 3d broadenings measured to be {epsilon}{sub 2p}=(-17{plus minus}4) eV, {Gamma}{sub 2p}=(25{plus minus}9) eV and {Gamma}{sub 3d}=(2.14{plus minus}0.18) meV for anti p{sup 3}He and {epsilon}{sub 2p}=(-18{plus minus}2) eV, {Gamma}{sub 2p}=(45{plus minus}5) eV and {Gamma}{sub 3d}=(2.36{plus minus}0.10) meV for anti p{sup 4}He. (orig.).

  10. Diffusive thermal conductivity of the A1-phase of superfluid 3He at low temperatures

    Science.gov (United States)

    Afzali, R.; Ebrahimian, N.

    2005-07-01

    The diffusive thermal conductivity tensor of the A1-phase of superfluid 3He at low temperatures and melting pressure are calculated beyond the s-p approximation, by using the Boltzmann equation approach. The interaction between normal-normal, normal-Bogoliubov and Bogoliubov-Bogoliubov quasiparticles in the collision integrals are considered for important scattering processes such as binary process. At low temperatures, we show that the scattering between Bogoliubov and normal quasiparticles in binary processes plays an important role in the A1-phase, and Bogoliubov-Bogoliubov interaction is ignorable. We show that the two normal and superfluid components take part in elements of the diffusive thermal conductivity tensor differently. We obtain the result that the elements of the diffusive thermal conductivities, Kxx, Kyy and Kzz, are proportional to T-1, and also that the superfluid components of the diffusive thermal conductivity tensor, K_{xx \\uparrow } and K_{zz \\uparrow } , are proportional to T3 and T, respectively.

  11. 3He/4He Ratio in Olivines from Linosa, Ustica, and Pantelleria Islands (Southern Italy

    Directory of Open Access Journals (Sweden)

    Elise Fourré

    2012-01-01

    Full Text Available We report helium isotope data for 0.03–1 Ma olivine-bearing basaltic hawaiites from three volcanoes of the southern Italy magmatic province (Ustica, Pantelleria, and Linosa Islands. Homogenous 3He/4He ratios (range: 7.3–7.6 Ra for the three islands, and their similarity with the ratio of modern volcanic gases on Pantelleria, indicate a common magmatic end-member. In particular, Ustica (7.6±0.2 Ra clearly differs from the nearby Aeolian Islands Arc volcanism, despite its location on the Tyrrhenian side of the plate boundary. Although limited in size, our data set complements the large existing database for helium isotope in southern Italy and adds further constraints upon the spatial extent of intraplate alkaline volcanism in southern Mediterranea. As already discussed by others, the He-Pb isotopic signature of this magmatic province indicates a derivation from a mantle diapir of a OIB-type that is partially diluted by the depleted upper mantle (MORB mantle at its periphery.

  12. Quasi-free photoproduction of eta-mesons off 3He nuclei

    CERN Document Server

    Witthauer, L; Keshelashvili, I; Aguar-Bartolome, P; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Beck, R; Bekrenev, V; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Demissie, B; Dieterle, M; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Glazier, D I; Hamilton, D; Heid, E; Hornidge, D; Howdle, D; Huber, G M; Jaegle, I; Jahn, O; Jude, T C; Kaeser, A; Kashevarov, V L; Kondratiev, R; Korolija, M; Kruglov, S P; Krusche, B; Kulbardis, A; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; Martinez, M; McGeorge, J C; McNicoll, E; Metag, V; Middleton, D G; Mushkarenkov, A; Nefkens, B M K; Nikolaev, A; Novotny, R; Oberle, M; Ostrick, M; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S; Robinson, J; Rosner, G; Rost, M; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D; Starostin, A; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Watts, D P

    2013-01-01

    Quasi-free photoproduction of $\\eta$-mesons has been measured off nucleons bound in $^3$He nuclei for incident photon energies from the threshold region up to 1.4 GeV. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with an almost $4\\pi$ covering electromagnetic calorimeter, combining the TAPS and Crystal Ball detectors. The $\\eta$-mesons were detected in coincidence with the recoil nucleons. This allowed a comparison of the production cross section off quasi-free protons and quasi-free neutrons and a full kinematic reconstruction of the final state, eliminating effects from nuclear Fermi motion. In the $S_{11}$(1535) resonance peak, the data agree with the neutron/proton cross section ratio extracted from measurements with deuteron targets. More importantly, the prominent structure observed in photoproduction off quasi-free neutrons bound in the deuteron is also clearly observed. Its parameters (width, strength) are consistent with the expectations from the deuteron r...

  13. Propagation of zero sound in superfluid {sup 3}He-B under magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Ashida, Masami; Hara, Jun`ichiro [Yamaguchi Univ. (Japan); Nagai, Katsuhiko [Hiroshima Univ. (Japan)

    1996-10-01

    The authors present a theory of zero sound propagation in superfluid {sup 3}He-B with an order parameter strongly distorted by magnetic field. A general formula of the dispersion relation for arbitrary magnetic field in the collisionless regime is derived within the weak coupling theory and under the assumption of particle-hole symmetry. The Landau parameters are taken into account up to F{sub 2}{sup 2} and F{sub 0}{sup a}. Numerical results for the sound velocity and absorption spectrum are presented. The authors show that the collective mode J = 1, J{sub z} = 0 yields a sizable peak in the sound absorption spectrum under weak but finite magnetic field. The quasi-particle excitations under magnetic field also exhibit cusp-like fine structures in the absorption spectrum. The authors show that the anomalies discovered by Ling et al. and Saunders et al. near the pair breaking edge in the q {perpendicular} H geometry consist of the J = 1, J{sub z} = 0 collective mode and the pair breaking cusps in the J{sub z} = 0, {plus_minus} 2 channels.

  14. A capture-gated neutron calorimeter using plastic scintillators and 3He drift tubes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhehui [Los Alamos National Laboratory; Morris, Christopher L [Los Alamos National Laboratory; Spaulding, Randy J [Los Alamos National Laboratory; Bacon, Jeffrey D [Los Alamos National Laboratory; Borozdin, Konstantin N [Los Alamos National Laboratory; Chung, Kiwhan [Los Alamos National Laboratory; Clark, Deborah J [Los Alamos National Laboratory; Green, Jesse A [Los Alamos National Laboratory; Greene, Steven J [Los Alamos National Laboratory; Hogan, Gary E [Los Alamos National Laboratory; Jason, Andrew [Los Alamos National Laboratory; Lisowski, Paul W [Los Alamos National Laboratory; Makela, Mark F [Los Alamos National Laboratory; Mariam, Fessaha G [Los Alamos National Laboratory; Miyadera, Haruo [Los Alamos National Laboratory; Murray, Matthew M [Los Alamos National Laboratory; Saunders, Alexander [Los Alamos National Laboratory; Wysocki, Frederick J [Los Alamos National Laboratory; Gray, Frederick E [REGIS UNIV.

    2010-01-01

    A segmented neutron calorimeter using nine 4-inch x 4-inch x 48-inch plastic scintillators and sixteen 2-inch-diameter 48-inch-long 200-mbar-{sup 3}He drift tubes is described. The correlated scintillator and neutron-capture events provide a means for n/{gamma} discrimination, critical to the neutron calorimetry when the {gamma} background is substantial and the {gamma} signals are comparable in amplitude to the neutron signals. A single-cell prototype was constructed and tested. It can distinguish between a {sup 17}N source and a {sup 252}Cf source when the {gamma} and the thermal neutron background are sufficiently small. The design and construction of the nine-cell segmented detector assembly follow the same principle. By recording the signals from individual scintillators, additional {gamma}-subtraction schemes, such as through the time-of-flight between two scintillators, may also be used. The variations of the light outputs from different parts of a scintillator bar are less than 10%.

  15. Neutral beam injection in a D-{sup 3}He FRC reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Hugo; Farengo, Ricardo [Centro Atomico Bariloche (CNEA) and Instituto Balseiro (UNC-CNEA) 8400 S. C. de Bariloche, RN (Argentina)

    2007-06-15

    The use of neutral beam injection (NBI) to sustain a fraction of the plasma current in a field reversed configuration (FRC) reactor operating with the D-{sup 3}He reaction is studied. A Monte Carlo code already used to study NBI in medium size FRCs is employed (Lifschitz A F, Farengo R and Arista N R 2002 Nucl. Fusion 42 863, Lifschitz A F, Farengo R and Arista N R 2002 Plasma Phys. Control. Fusion 44 1979, Lifschitz A F, Farengo R and Hoffman A L 2004 Nucl. Fusion 44 1015) and the plasma parameters are similar to those proposed in the ARTEMIS (Momota H, Ishida A, Kohzaki Y, Miley G, Ohi S, Ohnishi M, Sato K, Steinhauer L, Tomita Y and Tuszewki M 1992 Fusion Technol. 21 2307) conceptual reactor design. A simple analysis shows that the driven current cannot reach the values quoted in the ARTEMIS project and a procedure to search for plasma parameters that result in higher efficiencies is presented.

  16. CAST search for sub-eV mass solar axions with $^{3}$He buffer gas

    CERN Document Server

    Aune, S; Belov, A; Borghi, S; Brauninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Ezer, C; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galan, J; Garcia, J A; Gardikiotis, A; Gazis, E N; Geralis, T; Giomataris, I; Gninenko, S; Gomez, H; Gruber, E; Guthorl, T; Hartmann, R; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakovcic, K; Karuza, M; Konigsmann, K; Kotthaus, R; Krcmar, M; Kuster, M; Lakic, B; Laurent, J M; Liolios, A; Ljubicic, A; Lozza, V; Lutz, G; Luzon, G; Morales, J; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Rashba, T; Riege, H; Rodriguez, A; Rosu, M; Ruz, J; Savvidis, I; Silva, P S; Solanki, S.K; Stewart, L; Tomas, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J A; Vogel, J K; Yildiz, S C; Zioutas, K

    2011-01-01

    The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using 3He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with 4He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV < m_a < 0.64 eV. From the absence of excess X-rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_ag < 2.3 x 10^{-10} GeV^{-1} at 95% CL, the exact value depending on the pressure setting. KSVZ axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In future we will extend our search to m_a < 1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

  17. Absolute Charge Exchange Cross Sections for ^3He^2+ Collisions with ^4He and H_2

    Science.gov (United States)

    Mawhorter, R. J.; Greenwood, J.; Smith, S. J.; Chutjian, A.

    2002-05-01

    The JPL charge exchange beam-line(J.B. Greenwood, et al., Phys. Rev A 63), 062707 (2001) was modified to increase the forward acceptance angle and enable the measurement of total charge-exchange cross sections for slow, light, highly-charged ion collisions with neutral targets(R. E. Olson and M. Kimura, J. Phys. B 15), 4231 (1982). Data are presented for single charge exchange cross sections for ^3He^2+ nuclei scattered by ^4He and H2 in the energy range 0.33-4.67 keV/amu. For both targets there is good agreement with Kusakabe, et al.(T. Kusakabe, et al., J. Phys. Soc. Japan 59), 1218 (1990). Angular collection is studied by a comparison with differential measurements(D. Bordenave-Montesquieu and R. Dagnac, J. Phys. B 27), 543 (1994), as well as with earlier JPL results(J.B. Greenwood, et al., Ap. J. 533), L175 (2000), ibid. 529, 605 (2000) using heavier projectiles and targets. This work was carried out at JPL/Caltech, and was supported through contract with NASA. RJM thanks the NRC for a Senior Associateship at JPL.

  18. End-compensated magnetostatic cavity for polarized 3He neutron spin filters.

    Science.gov (United States)

    McIver, J W; Erwin, R; Chen, W C; Gentile, T R

    2009-06-01

    We have expanded upon the "Magic Box" concept, a coil driven magnetic parallel plate capacitor constructed out of mu-metal, by introducing compensation sections at the ends of the box that are tuned to limit end-effects similar to those of short solenoids. This ability has reduced the length of the magic box design without sacrificing any loss in field homogeneity, making the device far more applicable to the often space limited neutron beam line. The appeal of the design beyond affording longer polarized 3He lifetimes is that it provides a vertical guide field, which facilitates neutron spin transport for typical polarized beam experiments. We have constructed two end-compensated magic boxes of dimensions 28.4 x 40 x 15 cm3 (length x width x height) with measured, normalized volume-averaged transverse field gradients ranging from 3.3 x 10(-4) to 6.3 x 10(-4) cm(-1) for cell sizes ranging from 8.1 x 6.0 to 12.0 x 7.9 cm2 (diameter x length), respectively.

  19. End-compensated magnetostatic cavity for polarized {sup 3}He neutron spin filters

    Energy Technology Data Exchange (ETDEWEB)

    McIver, J. W.; Erwin, R.; Gentile, T. R. [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899 (United States); Chen, W. C. [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899 (United States); Indiana University, Bloomington, Indiana 47408 (United States)

    2009-06-15

    We have expanded upon the ''Magic Box'' concept, a coil driven magnetic parallel plate capacitor constructed out of mu-metal, by introducing compensation sections at the ends of the box that are tuned to limit end-effects similar to those of short solenoids. This ability has reduced the length of the magic box design without sacrificing any loss in field homogeneity, making the device far more applicable to the often space limited neutron beam line. The appeal of the design beyond affording longer polarized {sup 3}He lifetimes is that it provides a vertical guide field, which facilitates neutron spin transport for typical polarized beam experiments. We have constructed two end-compensated magic boxes of dimensions 28.4x40x15 cm{sup 3} (lengthxwidthxheight) with measured, normalized volume-averaged transverse field gradients ranging from 3.3x10{sup -4} to 6.3x10{sup -4} cm{sup -1} for cell sizes ranging from 8.1x6.0 to 12.0x7.9 cm{sup 2} (diameterxlength), respectively.

  20. An array of low-background 3He proportional counters for the Sudbury Neutrino Observatory

    Science.gov (United States)

    Amsbaugh, J. F.; Anaya, J. M.; Banar, J.; Bowles, T. J.; Browne, M. C.; Bullard, T. V.; Burritt, T. H.; Cox-Mobrand, G. A.; Dai, X.; Deng, H.; Di Marco, M.; Doe, P. J.; Dragowsky, M. R.; Duba, C. A.; Duncan, F. A.; Earle, E. D.; Elliott, S. R.; Esch, E.-I.; Fergani, H.; Formaggio, J. A.; Fowler, M. M.; Franklin, J. E.; Geissbühler, P.; Germani, J. V.; Goldschmidt, A.; Guillian, E.; Hallin, A. L.; Harper, G.; Harvey, P. J.; Hazama, R.; Heeger, K. M.; Heise, J.; Hime, A.; Howe, M. A.; Huang, M.; Kormos, L. L.; Kraus, C.; Krauss, C. B.; Law, J.; Lawson, I. T.; Lesko, K. T.; Loach, J. C.; Majerus, S.; Manor, J.; McGee, S.; Miknaitis, K. K. S.; Miller, G. G.; Morissette, B.; Myers, A.; Oblath, N. S.; O'Keeffe, H. M.; Ollerhead, R. W.; Peeters, S. J. M.; Poon, A. W. P.; Prior, G.; Reitzner, S. D.; Rielage, K.; Robertson, R. G. H.; Skensved, P.; Smith, A. R.; Smith, M. W. E.; Steiger, T. D.; Stonehill, L. C.; Thornewell, P. M.; Tolich, N.; VanDevender, B. A.; Van Wechel, T. D.; Wall, B. L.; Wan Chan Tseung, H.; Wendland, J.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.; Wouters, J. M.

    2007-09-01

    An array of Neutral-Current Detectors (NCDs) has been built in order to make a unique measurement of the total active flux of solar neutrinos in the Sudbury Neutrino Observatory (SNO). Data in the third phase of the SNO experiment were collected between November 2004 and 2006, after the NCD array was added to improve the neutral-current sensitivity of the SNO detector. This array consisted of 36 strings of proportional counters filled with a mixture of 3He and CF 4 gas capable of detecting the neutrons liberated by the neutrino-deuteron neutral-current reaction in the D 2O, and four strings filled with a mixture of 4He and CF 4 gas for background measurements. The proportional counter diameter is 5 cm. The total deployed array length was 398 m. The SNO NCD array is the lowest-radioactivity large array of proportional counters ever produced. This article describes the design, construction, deployment, and characterization of the NCD array, discusses the electronics and data acquisition system, and considers event signatures and backgrounds.

  1. Ratios of Elastic Scattering of Pions from 3H and 3He

    CERN Document Server

    Briscoe, W J; Carter, R W C; Dhuga, K S; Matthews, S K; Nicholas, N J; Greene, S J; Nefkens, B M K; Price, J W; Isenhower, L D; Sadler, M E; Slaus, I; Supek, I

    2002-01-01

    We have measured the elastic-scattering ratios of normalized yields for charged pions from 3H and 3He in the backward hemisphere. At 180 MeV, we completed the angular distribution begun with our earlier measurements, adding six data points in the angular range of 119 deg to 169 deg in the pi-nucleus center of mass. We also measured an excitation function with data points at 142, 180, 220, and 256 MeV incident pion energy at the largest achievable angle for each energy between 160 deg and 170 deg in the pi-nucleus center of mass. This excitation function corresponds to the energies of our forward-hemisphere studies. The data, taken as a whole, show an apparent role reversal of the two charge-symmetric ratios r1 and r2 in the backward hemisphere. Also, for data > 100 deg we observe a strong dependence on the four-momentum transfer squared (-t) for all of the ratios regardless of pion energy or scattering angle, and we find that the superratio R data match very well with calculations based on the forward-hemisph...

  2. Dispersion induced splitting of the collective mode spectrum in A-phase of superfluid 3He

    Science.gov (United States)

    Brusov, Peter; Brusov, Pavel

    2009-05-01

    The whole collective mode spectrum in A-phase of superfluid 3He with dispersion corrections is calculated. The degeneracy of clapping-modes depends on the direction of the collective mode momentum k with respect to the vector l (mutual orbital moment of Cooper pairs), namely: the mode degeneracy remains the same as in case of zero momentum k for k∥l only. For any other directions there is a three-fold splitting of these modes, which reaches maximum for k⊥l. The obtained results means that new interesting features can be observed in ultrasound experiments in axial-phase: the change of the number of peaks in ultrasound absorption into clapping-mode. Single peak, observed for these modes in axial-phase by Ling et al. [R. Ling, W. Wojtanowski, J. Saunders, E.R. Dobbs, J. Low Temp. Phys. 78 (1990) 187] will split into three peaks under change the ultrasound direction with respect to the vector l.

  3. Investigation of the dd -> 3He n \\pi 0 reaction with WASA-at-COSY

    CERN Document Server

    :,; Augustyniak, W; Bardan, W; Bashkanov, M; Bergmann, F S; Berłowski, M; Bhatt, H; Büscher, M; Calén, H; Ciepał, I; Clement, H; Coderre, D; Czerwiński, E; Demmich, K; Doroshkevich, E; Engels, R; Erven, W; Eyrich, W; Fedorets, P; Föhl, K; Fransson, K; Goldenbaum, F; Goslawski, P; Goswami, A; Grigoryev, K; Gullström, C --O; Hanhart, C; Hauenstein, F; Heijkenskjöld, L; Hejny, V; Hinterberger, F; Hodana, M; Höistad, B; Jany, A; Jany, B R; Jarczyk, L; Johansson, T; Kamys, B; Kemmerling, G; Khan, F A; Khoukaz, A; Kirillov, D A; Kistryn, S; Klaja, J; Kleines, H; Kłos, B; Krapp, M; Krzemień, W; Kulessa, P; Kupść, A; Lalwani, K; Lersch, D; Li, L; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Mariański, B; Mikirtychiants, M; Morsch, H --P; Moskal, P; Nandi, B K; Ohm, H; Ozerianska, I; del Rio, E Perez; Piskunov, N M; Pluciński, P; Podkopał, P; Prasuhn, D; Pricking, A; Pszczel, D; Pysz, K; Pyszniak, A; Redmer, C F; Ritman, J; Roy, A; Rudy, Z; Sawant, S; Schmidt, A; Schadmand, S; Sefzick, T; Serdyuk, V; Shah, N; Siemaszko, M; Siudak, R; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Stephan, E; Sterzenbach, G; Stockhorst, H; Ströher, H; Szczurek, A; Tolba, T; Trzciński, A; Varma, R; Wagner, G J; W\\keglorz, W; Wolke, M; Wrońska, A; Wüstner, P; Wurm, P; Yamamoto, A; Yuan, X; Zabierowski, J; Zheng, C; Zieliński, M J; Zipper, W; Złomańczuk, J; Żuprański, P; Żurek, M

    2013-01-01

    An exclusive measurement of the dd -> 3He n \\pi 0 reaction was carried at a beam momentum of p = 1.2 GeV/c using the WASA-at-COSY facility. For the first time data on the total cross section as well as differential distributions were obtained. The data are described with a phenomenological approach based on a combination of a quasi-free model and a partial wave expansion for three-body reaction. The total cross section is found to be \\sigma(tot) = (2.89 +- 0.01(stat) +- 0.06(sys) +- 0.29(norm)) \\mu b. The contribution of the quasi-free processes (with the neutron being target or beam spectator) accounts for 38% of the total cross section and dominates the differential distributions in specific regions of the phase space. The remaining part of the cross section can be described within a partial wave decomposition indicating the significance of p-wave contributions in the final state.

  4. Ultra-High Sensitivity Techniques for the Determination of 3 He /4 He Abundances in Helium by Accelerator Mass Spectrometry

    Science.gov (United States)

    Mumm, H. P.; Huber, M.; Bauder, W.; Abrams, N.; Deibel, C.; Huffer, C.; Huffman, P.; Schelhammer, K.; Janssens, R.; Jiang, C.; Scott, R.; Pardo, R.; Rehm, K.; Vondrasek, R.; Swank, C.; O'Shaughnessy, C.; Paul, M.; Yang, L.

    2017-01-01

    We report the development of an Accelerator Mass Spectrometry technique to measure the 3He/4He isotopic ratio using a radio frequency (RF) discharge source and the ATLAS facility at Argonne National Laboratory. Control over 3He/4He ratio in helium several orders of magnitude lower than natural abundance is critical for neutron lifetime and source experiments using liquid helium. Due to low ultimate beam currents, the ATLAS accelerator and beam line were tuned using a succession of species of the same M/q. A unique RF source was developed for the experiment due to large natural 3He backgrounds. Analog H_3 + and DH + molecular ions are eliminated by dissociation via a gold stripper foil near the detector. The stripped ions were dispersed in a magnetic spectrograph and 3He2 + ions counted in the focal plane detector. This technique is sensitive to 3 He /4 He ratios in the regime of 10-12 with backgrounds that appear to be below 10-14. The techniques used to reduce the backgrounds and remaining outstanding problems will be presented along with results from measurements on high purity 4He samples.

  5. Increasing the pump-up rate to polarize 3He gas using spin-exchange optical pumping method

    Science.gov (United States)

    Lee, Wai Tung; Tong, Xin; Rich, Dennis; Liu, Yun; Fleenor, Michael; Ismaili, Akbar; Pierce, Joshua; Hagen, Mark; Dadras, Jonny; Robertson, J. Lee

    2009-09-01

    In recent years, polarized 3He gas has increasingly been used as neutron polarizers and polarization analyzers. Two of the leading methods to polarize the 3He gas are the spin-exchange optical pumping (SEOP) method and the meta-stable exchange optical pumping (MEOP) method. At present, the SEOP setup is comparatively compact due to the fact that it does not require the sophisticated compressor system used in the MEOP method. The temperature and the laser power available determine the speed, at which the SEOP method polarizes the 3He gas. For the quantity of gas typically used in neutron scattering work, this speed is independent of the quantity of the gas required, whereas the polarizing time using the MEOP method is proportional to the quantity of gas required. Currently, using the SEOP method to polarize several bar-liters of 3He to 70% polarization would require 20-40 h. This is an order of magnitude longer than the MEOP method for the same quantity of gas and polarization. It would therefore be advantageous to speed up the SEOP process. In this article, we analyze the requirements for temperature, laser power, and the type of alkali used in order to shorten the time required to polarize 3He gas using the SEOP method.

  6. Effects of. Delta. -isobar degrees of freedom on the reactions sup 3 He(n,. gamma. ) sup 4 He and sup 3 He(p,e sup +. nu. sub e ) sup 4 He at low-energy

    Energy Technology Data Exchange (ETDEWEB)

    Schiavilla, R.

    1991-01-01

    The cross sections of the radiative {sup 3}He(n,{gamma}){sup 4}He and weak {sup 3}He(p,e{sup +}{nu}{sub e}){sup 4}He capture reactions at thermal neutron and keV proton energies have been calculated with the Variational Monte Carlo method. The ground state and low-energy continuum wave functions have been determined variationally from a realistic Hamiltonian, and include both nucleon and {Delta}-isobar degrees of freedom. The electroweak transition operator contains one- and two-body components in the N + {Delta} Hilbert space.

  7. Effects of {Delta}-isobar degrees of freedom on the reactions {sup 3}He(n,{gamma}){sup 4}He and {sup 3}He(p,e{sup +}{nu}{sub e}){sup 4}He at low-energy

    Energy Technology Data Exchange (ETDEWEB)

    Schiavilla, R.

    1991-12-31

    The cross sections of the radiative {sup 3}He(n,{gamma}){sup 4}He and weak {sup 3}He(p,e{sup +}{nu}{sub e}){sup 4}He capture reactions at thermal neutron and keV proton energies have been calculated with the Variational Monte Carlo method. The ground state and low-energy continuum wave functions have been determined variationally from a realistic Hamiltonian, and include both nucleon and {Delta}-isobar degrees of freedom. The electroweak transition operator contains one- and two-body components in the N + {Delta} Hilbert space.

  8. Quasi-bound alpha resonant states populated by the {sup 12}C({sup 6}Li, d) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, M.R.D.; Borello-Lewin, T.; Miyake, H.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F.; Foti, A.; Agodi, C.; Cavallaro, M. [Istituto Nazionale di Fisica Nucleare (LNS/INFN), Catania (Italy). Lab. Nazionali del Sud; Ukita, G.M. [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Faculdade de Psicologia

    2012-07-01

    Full text: The alpha cluster phenomenon in the light nuclei structure has been the subject of a long time investigation since the proposal of the Ikeda diagrams [1]. The main purpose of the research program in progress is the investigation of this phenomenon in (x{alpha}) and (x{alpha}+n) nuclei through the ({sup 6}Li, d) alpha transfer reaction [2-4]. Alpha resonant states around the (4{alpha}) threshold in the nucleus {sup 16}O are the focus of the present contribution. In fact, the importance of these resonances at the elements production in stars is recognized, as primarily pointed out by Hoyle in {sup 12}C [6]. The existence of a rotational band with the {alpha} +{sup 12} C (Hoyle) cluster state structure was recently demonstrated by Ohkubo and Hirabayashi [6]. In order to explore this region of interest, measurements of the {sup 12}C({sup 6}Li, d){sup 16}O reaction up to 17 MeV of excitation at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique (plates Fuji G6B, 50 {mu}m thick). Spectra associated with six scattering angles, from 5 deg to 29 deg in the laboratory frame, each one 50 cm along the focal surface, were measured. Several narrow resonances with a quasi-bound behavior embedded in the continuum were detected and the resolution of 25 keV allowed for the separation of doublets not resolved before [7,8]. The absolute cross sections and the respective deuteron angular distributions were determined and the analysis is in progress. [1] K. Ikeda et al., Prog. Theor. Phys. Suppl. E 68, 464 (1968); H. Horiuchi, K. Ikeda, and Y. Suzuki, ibid. 44, 225 (1978). [2] M.R.D.Rodrigues et al., in12th International Conference on Nuclear Reaction Mechanism, Varenna, Italy, edited by F. Cerutti and A. Ferrari , CERN Proceedings, 2010-2, pp. 331- 335. [3] T. Borello-Lewin et al., Proceedings of SOTANCP2, Brussels, Belgium 2010, edited by P. Descouvemount et al., Int. J

  9. Threshold groundwater ages and young water fractions estimated from 3H, 3He, and 14C

    Science.gov (United States)

    Kirchner, James; Jasechko, Scott

    2016-04-01

    It is widely recognized that a water sample taken from a running stream is not described by a single age, but rather by a distribution of ages. It is less widely recognized that the same principle holds true for groundwaters, as indicated by the commonly observed discordances between model ages obtained from different tracers (e.g., 3H vs 14C) in the same sample. Water age distributions are often characterized by their mean residence times (MRT's). However, MRT estimates are highly uncertain because they depend on the shape of the assumed residence time distribution (in particular on the thickness of the long-time tail), which is difficult or impossible to constrain with data. Furthermore, because MRT's are typically nonlinear functions of age tracer concentrations, they are subject to aggregation bias. That is, MRT estimates derived from a mixture of waters with different ages (and thus different tracer concentrations) will systematically underestimate the mixture's true mean age. Here, building on recent work with stable isotope tracers in surface waters [1-3], we present a new framework for using 3H, 3He and 14C to characterize groundwater age distributions. Rather than describing groundwater age distributions by their MRT, we characterize them by the fraction of the distribution that is younger or older than a threshold age. The threshold age that separates "young" from "old" water depends on the characteristics of the specific tracer, including its history of atmospheric inputs. Our approach depends only on whether a given slice of the age distribution is younger or older than the threshold age, but not on how much younger or older it is. Thus our approach is insensitive to the tails of the age distribution, and is therefore relatively unaffected by uncertainty in the distribution's shape. Here we show that concentrations of 3H, 3He, and 14C are almost linearly related to the fractions of water that are younger or older than specified threshold ages. These

  10. Reaction mechanism and characteristics of $T_{20}$ in $d + ^3He$ backward elastic scattering at intermediate energies

    CERN Document Server

    Tanifuji, M; Iseri, Y; Uesaka, T; Sakamoto, N; Satou, Y; Itoh, K; Sakai, H; Tamii, A; Ohnishi, T; Sekiguchi, K; Yako, K; Sakoda, S; Okamura, H; Suda, K; Wakasa, T

    2000-01-01

    For backward elastic scattering of deuterons by ^3He, cross sections \\sigma and tensor analyzing power T_{20} are measured at E_d=140-270 MeV. The data are analyzed by the PWIA and by the general formula which includes virtual excitations of other channels, with the assumption of the proton transfer from ^3He to the deuteron. Using ^3He wave functions calculated by the Faddeev equation, the PWIA describes global features of the experimental data, while the virtual excitation effects are important for quantitative fits to the T_{20} data. Theoretical predictions on T_{20}, K_y^y (polarization transfer coefficient) and C_{yy} (spin correlation coefficient) are provided up to GeV energies.

  11. Observation of the n(3He,t)p Reaction by Detection of Far-Ultraviolet Radiation

    CERN Document Server

    Thompson, Alan K; Cooper, John W; Hughes, Patrick; Vest, Robert E; Clark, Charles W

    2008-01-01

    We have detected Lyman alpha radiation as a product of the n(3He,t)p nuclear reaction occurring in a cell of 3He gas. The predominant source of this radiation appears to be decay of the 2p state of tritium produced by charge transfer and excitation collisions with the background 3He gas. Under the experimental conditions reported here we find yields of tens of Lyman alpha photons for every neutron reaction. These results suggest a method of cold neutron detection that is complementary to existing technologies that use proportional counters. In particular, this approach may provide single neutron sensitivity with wide dynamic range capability, and a class of neutron detectors that are compact and operate at relatively low voltages.

  12. The injection of ten electron/3He-rich SEP events

    Science.gov (United States)

    Wang, Linghua; Mason, Glenn; Krucker, Samuel; Li, Gang

    2016-07-01

    We have derived the particle injections at the Sun for ten good electron/ ^{3}He-rich solar energetic particle (SEP) events, using a 1.2 AU particle path length (suggested by analysis of the velocity dispersion). The inferred solar injections of high-energy (˜10 to 300 keV) electrons and of ˜MeV/nucleon ions (carbon and heavier) start with a delay of 17±3 minutes and 75±±14 minutes, respectively, after the injection of low-energy (˜0.4 to 9 keV) electrons. The injection duration (averaged over energy) ranges from ˜200 to 550 minutes for ions, from ˜90 to 160 minutes for low-energy electrons, and from ˜10 to 30 minutes for high-energy electrons. Most of the selected events have no reported H_{α} flares or GOES SXR bursts, but all have type III radio bursts that typically start after the onset of a low-energy electron injection. All nine events with SOHO/LASCO coverage have a relatively fast (>570km/s), mostly narrow (≲30°), west-limb coronal mass ejection (CME) that launches near the start of the low-energy electron injection, and reaches an average altitude of ˜1.0 and 4.7 R _{S} , respectively, at the start of the high-energy electron injection and of the ion injection. The electron energy spectra show a continuous power law extending across the transition from low to high energies, suggesting that the low-energy electron injection may provide seed electrons for the delayed high-energy electron acceleration. The delayed ion injections and high ionization states may suggest an ion acceleration along the lower altitude flanks, rather than at the nose of the CMEs.

  13. Heterogeneous disease progression and treatment response in a C3HeB/FeJ mouse model of tuberculosis

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Lanoix

    2015-06-01

    Full Text Available Mice are the most commonly used species for non-clinical evaluations of drug efficacy against tuberculosis (TB. Unlike commonly used strains, C3HeB/FeJ mice develop caseous necrosis in the lung, which might alter the representation of drug efficacy in a way that is more like human TB. Because the development of such pathology requires time, we investigated the effect of infection incubation period on the activity of six drugs in C3HeB/FeJ and BALB/c mice. Mice were aerosol infected and held for 6, 10 or 14 weeks before receiving therapy with rifampin (RIF, rifapentine (RPT, pyrazinamide (PZA, linezolid (LZD, sutezolid (PNU or metronidazole (MTZ for 4-8 weeks. Outcomes included pathological assessments, pH measurements of liquefied caseum and assessment of colony-forming unit (CFU counts from lung cultures. Remarkable heterogeneity in the timing and extent of disease progression was observed in C3HeB/FeJ mice, largely independent of incubation period. Likewise, drug efficacy in C3HeB/FeJ mice was not affected by incubation period. However, for PZA, LZD and PNU, dichotomous treatment effects correlating with the presence or absence of large caseous lesions were observed. In the case of PZA, its poor activity in the subset of C3HeB/FeJ mice with large caseous lesions might be explained by the pH of 7.36±0.09 measured in liquefied caseum. This study highlights the potential value of C3HeB/FeJ mice for non-clinical efficacy testing, especially for investigating the interaction of lesion pathology and drug effect. Careful use of this model could enhance the bridging of non-clinical results with clinical outcomes.

  14. A measurement of the absolute neutron beam polarization produced by an optically pumped sup 3 He neutron spin filter

    CERN Document Server

    Rich, D R; Crawford, B E; Delheij, P P J; Espy, M A; Haseyama, T; Jones, G; Keith, C D; Knudson, J; Leuschner, M B; Masaike, A; Masuda, Y; Matsuda, Y; Penttilae, S I; Pomeroy, V R; Smith, D A; Snow, W M; Szymanski, J J; Stephenson, S L; Thompson, A K; Yuan, V

    2002-01-01

    The capability of performing accurate absolute measurements of neutron beam polarization opens a number of exciting opportunities in fundamental neutron physics and in neutron scattering. At the LANSCE pulsed neutron source we have measured the neutron beam polarization with an absolute accuracy of 0.3% in the neutron energy range from 40 meV to 10 eV using an optically pumped polarized sup 3 He spin filter and a relative transmission measurement technique. sup 3 He was polarized using the Rb spin-exchange method. We describe the measurement technique, present our results, and discuss some of the systematic effects associated with the method.

  15. The 10B based Jalousie neutron detector - An alternative for 3He filled position sensitive counter tubes

    Science.gov (United States)

    Henske, M.; Klein, M.; Köhli, M.; Lennert, P.; Modzel, G.; Schmidt, C. J.; Schmidt, U.

    2012-09-01

    Over the last decades 3He filled proportional counter tubes were the working horse employed to serve as neutron counters especially in cases where large area coverage was required. Today the lack of 3He demands the development of an alternative technology. Here we present a prototype neutron detector that is based on a concept with solid 10B as neutron converter and aims for large area neutron detection applications. We report on first experimental results obtained with this prototype to demonstrate the feasibility and operational readiness of our concept.

  16. The {sup 10}B based Jalousie neutron detector - An alternative for {sup 3}He filled position sensitive counter tubes

    Energy Technology Data Exchange (ETDEWEB)

    Henske, M. [CDT CASCADE Detector Technologies GmbH, Hans-Bunte-Str. 8-10, 69123 Heidelberg (Germany); Klein, M., E-mail: martin.klein@physi.uni-heidelberg.de [Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany); CDT CASCADE Detector Technologies GmbH, Hans-Bunte-Str. 8-10, 69123 Heidelberg (Germany); Koehli, M.; Lennert, P.; Modzel, G. [Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany); Schmidt, C.J. [CDT CASCADE Detector Technologies GmbH, Hans-Bunte-Str. 8-10, 69123 Heidelberg (Germany); GSI Detector Laboratory, Planckstrasse 1, 64291 Darmstadt (Germany); Schmidt, U. [Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany)

    2012-09-11

    Over the last decades {sup 3}He filled proportional counter tubes were the working horse employed to serve as neutron counters especially in cases where large area coverage was required. Today the lack of {sup 3}He demands the development of an alternative technology. Here we present a prototype neutron detector that is based on a concept with solid {sup 10}B as neutron converter and aims for large area neutron detection applications. We report on first experimental results obtained with this prototype to demonstrate the feasibility and operational readiness of our concept.

  17. Neutron spin filter based on optically polarized sup 3 He in a near-zero magnetic field

    CERN Document Server

    Skoy, V R; Sorokin, V N; Kolachevsky, N N; Sobelman, I I; Sermyagin, A V

    2003-01-01

    A test of polarization of sup 3 He nuclei via spin-exchange collisions with optically pumped rubidium atoms in an extremely low applied magnetic field was carried out. Permalloy magnetic shields were used to prevent a fast relaxation of sup 3 He polarization owing to the inhomogeneity of a surrounding magnetic field. The whole installation was placed at the neutron beam line of the IBR-30 facility, and used as a neutron spin filter. Thus, a prototype of new design of neutron polarizer was introduced. We intend to apply this experience for the full-scale KaTRIn facility to test the time reversal violation in neutron-nuclear reactions.

  18. Neutron spin filter based on optically polarized {sup 3}He in a near-zero magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Skoy, V.R. E-mail: skoy@nf.jinr.ru; Prokofichev, Yu.V.; Sorokin, V.N.; Kolachevski, N.N.; Sobelman, I.I.; Sermyagin, A.V

    2003-04-01

    A test of polarization of {sup 3}He nuclei via spin-exchange collisions with optically pumped rubidium atoms in an extremely low applied magnetic field was carried out. Permalloy magnetic shields were used to prevent a fast relaxation of {sup 3}He polarization owing to the inhomogeneity of a surrounding magnetic field. The whole installation was placed at the neutron beam line of the IBR-30 facility, and used as a neutron spin filter. Thus, a prototype of new design of neutron polarizer was introduced. We intend to apply this experience for the full-scale KaTRIn facility to test the time reversal violation in neutron-nuclear reactions.

  19. Differences in Properties of 3He-rich SEP Events between Solar Cycle 24 and Earlier Cycles

    Science.gov (United States)

    Wiedenbeck, M. E.; Mason, G. M.; Ho, G. C.

    2013-12-01

    Since the launch of NASA's ACE spacecraft in 1997 we have been observing 3He-rich solar energetic particle (SEP) events using its ULEIS and SIS instruments. From those data it was determined that over the past 15+ years there has been a large variation in the fraction of time that energetic 3He could be detected near Earth, ranging from >80% near the maximum of solar cycle 23 to ISEE-3 during the period spanning the maxima of cycles 21 and 22.

  20. Polarisation of the omega meson in the pd-->3He+omega reaction at 1360 and 1450 MeV

    CERN Document Server

    Schonning, K; Bashkanov, M; Berlowski, M; Bogoslawsky, D; Calén, H; Clement, H; Demirors, L; Ekström, C; Fransson, K; Geren, L; Gustafsson, L; Höistad, B; Ivanov, G; Jacewicz, M; Jiganov, E; Johansson, T; Keleta, S; Khakimova, O; Koch, I; Kren, F; Kullander, Sven; Kupsc, A; Kuzmin, A; Lindberg, K; Marciniewski, P; Morosov, B; Oelert, W; Pauly, C; Pettersson, H; Petukhov, Yu P; Povtorejko, A; Ruber, R J M Y; Scobel, W; Shafigullin, R; Shwartz, B; Skorodko, T; Sopov, V; Stepaniak, J; Tegner, P -E; Engblom, P Thorngren; Tikhomirov, V; Turowiecki, A; Wagner, G J; Wilkin, C; Wolke, M; Zabierowski, J; Zartova, I; Zlomanczuk, Yu

    2008-01-01

    The tensor polarisation of omega mesons produced in the pd-->3He+omega reaction has been studied at two energies near threshold. The 3He nuclei were detected in coincidence with the pi0pi+pi- or pi0gamma decay products of the omega. In contrast to the case of phi meson production, the omega mesons are found to be unpolarised. This brings into question the applicability of the Okubo-Zweig-Iizuka rule when comparing the production of vector mesons in low energy hadronic reactions.

  1. Spatial distribution of {gamma} emissivity and fast ions during ({sup 3}He)D ICRF heating experiments on JET

    Energy Technology Data Exchange (ETDEWEB)

    Start, D.F.H. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Righi, E. [Imperial Coll. of Science and Technology, London (United Kingdom); Warrick, C. [UKAEA Culham Lab., Abingdon (United Kingdom)

    1994-07-01

    A model is presented that can simulate the {gamma} emissivity in the poloidal cross-section during ({sup 3}He)D ICRF heated discharges in JET plasmas, by merging information obtained from the fast ion distribution and from nuclear reactions producing the observed {gamma} emissivity (production of {gamma} photons during {sup 3}He-{sup 9}Be reactions). This technique can play an important role in the identification of plasma instabilities that affect the redistribution of the fast ions in the plasma, like the TAE modes and the ripple in the tokamak magnetic field. 9 refs., 4 figs., 1 tab.

  2. Geometrical aspects of reaction cross sections for {sup 3}He, {sup 4}He and {sup 12}C projectiles

    Energy Technology Data Exchange (ETDEWEB)

    Ingemarsson, A. [Uppsala Univ. (Sweden). Dept. of Radiation Sciences; Lantz, M. [Uppsala Univ. (Sweden). The Svedberg Laboratory

    2003-04-01

    A black-disc model combined with accurate matter densities has been used for an investigation of reaction cross sections for {sup 3}He, {sup 4}He and {sup 12}C projectiles. A simple relation is derived between the energy dependence of the reaction cross sections and the strength of the nucleon-nucleon interaction. A comparison is also made of the reaction cross sections for {sup 3}He and {sup 4}He for six different nuclei {sup 12}C, {sup 16}O, {sup 40}Ca, {sup 58,60}Ni and {sup 208}Pb.

  3. Conceptual design of a polarized 3He neutron spin filter for polarized neutron spectrometer POLANO at J-PARC

    Science.gov (United States)

    Ino, T.; Ohoyama, K.; Yokoo, T.; Itoh, S.; Ohkawara, M.; Kira, H.; Hayashida, H.; Sakai, K.; Hiroi, K.; Oku, T.; Kakurai, K.; Chang, L. J.

    2016-04-01

    A 3He neutron spin filter (NSF) has been designed for a new polarized neutron chopper spectrometer called the Polarization Analysis Neutron Spectrometer with Correlation Method (POLANO) at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. It is designed to fit in a limited space on the spectrometer as an initial neutron beam polarizer and is polarized in situ by spin exchange optical pumping. This will be the first generation 3He NSF on POLANO, and a polarized neutron beam up to 100 meV with a diameter of 50 mm will be available for research on magnetism, hydrogen materials, and strongly correlated electron systems.

  4. Spectroscopic strengths for /sup 6/Li-induced alpha-particle transfers on /sup 18/O at 72 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, T.; Ogino, K.; Kadota, Y.; Haga, K.; Kitahara, T.; Shiba, T.

    1982-08-01

    The /sup 18/O(/sup 6/Li,d)/sup 22/Ne reaction has been studied at 72-MeV bombarding energy. The angular distributions for transitions to low-lying states in /sup 22/Ne are fitted by exact finite-range distorted-wave Born approximation calculations and yield relative spectroscopic factors in good agreement with theoretical predictions.

  5. Multi-elemental characterization of organic liquid samples by use of a 13 MeV {sup 6}Li{sup 3+} beam

    Energy Technology Data Exchange (ETDEWEB)

    Liendo, J.A., E-mail: jliendo@usb.v [Department of Physics, Simon Bolivar University, PO Box 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Bernal, M.A., E-mail: mbernal@usb.v [Department of Physics, Simon Bolivar University, PO Box 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Gonzalez, A.C. [Centro de Fisica, Instituto Venezolano de Investigaciones Cientificas, Caracas (Venezuela, Bolivarian Republic of); Caussyn, D.D.; Fletcher, N.R.; Momotyuk, O.A. [Department of Physics, Florida State University, Tallahassee (United States); Muruganathan, R.M. [Department of Chemistry, Florida State University, Tallahassee (United States); Roeder, B.T.; Wiedenhoever, I. [Department of Physics, Florida State University, Tallahassee (United States); Fischer, T. [Department of Chemistry, Florida State University, Tallahassee (United States); Kemper, K.W.; Barber, P. [Department of Physics, Florida State University, Tallahassee (United States); Sajo-Bohus, L. [Department of Physics, Simon Bolivar University, PO Box 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of)

    2009-10-15

    Evaporated amniotic fluid (AF) targets have been bombarded with a 13 MeV {sup 6}Li{sup 3+} beam. Forward angle data have served to identify the {sup 1}H({sup 6}Li,{sup 1}H){sup 6}Li reaction as an alternative for hydrogen characterization of such organic samples. Detected {sup 6}Li ions elastically scattered from C, N, O, Na and Cl can also be used to determine the concentrations of these elements in AF. The analyzed AF samples have been diluted with distilled water. The effect of sample dilution on the improvement of spectrum energy resolution has been observed, confirming previous reports. The hydrogen concentration determined in the studied AF targets is shown to vary linearly with sample dilution. Two detector arrangements have been used to find out which detection scheme is the most convenient. The combination of a counter telescope and a single detector, set up at the same polar angle on the opposite side of the beam, seems to be the best choice to have a reliable particle identification and an adequate energy resolution simultaneously.

  6. Threshold behavior of interaction potential for the system 7Li + 64Ni: Comparison with 6Li + 64Ni

    Science.gov (United States)

    Shaikh, Md. Moin; Das, Mili; Roy, Subinit; Sinha, M.; Pradhan, M. K.; Basu, P.; Datta, U.; Ramachandran, K.; Shrivastava, A.

    2016-09-01

    The elastic scattering angular distributions for the system 7Li + 64Ni were measured in the bombarding energy range of 12 MeV ≤Elab ≤ 26.4 MeV. A phenomenological optical model analysis was performed for the measured data. The strengths of the fitted potential components at the surface were estimated to extract their variation with energy. Further analyses of the measured angular distributions were performed with a hybrid potential composed of a renormalized folded real and a phenomenological imaginary potential. Both the model potentials predict similar energy dependent behavior for the effective interaction potential around the barrier. Unlike the heavy targets, 7Li + 64Ni does not show a normal threshold behavior. It also does not clearly exhibit a behavior similar to 6Li + 64Ni. The real potential for 7Li + 64Ni does not exhibit any significant energy dependence and the imaginary potential strength remains almost independent of energy above the Coulomb barrier (∼ 14 MeV). However, at energies below the barrier, a sudden drop in the imaginary potential strength is observed.

  7. (/sup 6/Li,d) reactions on /sup 24/Mg and /sup 26/Mg at 73 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, T.; Haga, K.; Yasue, M.; Sato, K. (Tokyo Univ., Tanashi (Japan). Inst. for Nuclear Study); Ogino, K.; Kadota, Y.; Tochi, M.; Makino, K. (Kyoto Univ. (Japan). Faculty of Engineering); Kitahara, T. (Yamanashi Medical Coll. (Japan)); Shiba, T. (Kyoto Univ. (Japan). Lab. of Nuclear Reaction)

    1983-05-09

    The sup(24,26)Mg(/sup 6/Li, d)sup(28,30)Si reactions have been studied at 73 MeV bombarding energy. The angular distributions were analyzed with exact finite-range distorted wave Born approximation calculations assuming a direct ..cap alpha..-cluster transfer. Extracted spectroscopic strengths leading to low-lying levels of /sup 28/Si and relative spectroscopic strengths between transitions to /sup 28/Si and /sup 30/Si ground states are consistent with those previously obtained by several ..cap alpha..-transfer reactions. Many strongly populated levels have been observed at Esub(x)> or approx.10 MeV for /sup 28/Si. A marked similarity was found between the deuteron spectrum and the /sup 24/Mg(..cap alpha.., ..cap alpha..)/sup 24/Mg excitation function in this excitation energy region. A brief comparison of the present ..cap alpha..-transfer results with previous two-nucleon transfer data leading to sup(28,30)Si is also presented.

  8. Hypernuclear production cross section in the reaction of 6Li + 12C at 2A GeV

    Directory of Open Access Journals (Sweden)

    C. Rappold

    2015-07-01

    Full Text Available Hypernuclear production cross sections have been deduced for the first time with induced reaction of heavy ion beam on fixed target and by means of the invariant mass method by the HypHI Collaboration exploiting the reaction of 6Li + 12C at 2A GeV or sNN=2.70 GeV. A production cross section of 3.9±1.4 μb for 3ΛH and of 3.1±1.0 μb for 4ΛH respectively in the projectile rapidity region was inferred as well as the total production cross section of the Λ hyperon was measured and found to be equal to 1.7±0.8 mb. A global fit based on a Bayesian approach was performed in order to include and propagate statistical and systematic uncertainties. Production ratios of 3ΛH/4ΛH, 3ΛH/Λ and 4ΛH/Λ were included in the inference procedure. The strangeness population factors S3 and S4 of 3ΛH and 4ΛH respectively were extracted. In addition, the multiplicities of the Λ hyperon, 3ΛH, and 4ΛH together with the rapidity and transversal momentum density distributions of the observed hypernuclei were extracted and reported.

  9. Development of neutron-monitor detector using liquid organic scintillator coupled with 6Li + ZnS(Ag) Sheet.

    Science.gov (United States)

    Sato, Tatsuhiko; Endo, Akira; Yamaguchi, Yasuhiro; Takahashi, Fumiaki

    2004-01-01

    A phoswitch-type detector has been developed for monitoring neutron doses in high-energy accelerator facilities. The detector is composed of a liquid organic scintillator (BC501A) coupled with ZnS(Ag) sheets doped with 6Li. The dose from neutrons with energies above 1 MeV is evaluated from the light output spectrum of the BC501A by applying the G-function, which relates the spectrum to the neutron dose directly. The dose from lower energy neutrons, on the other hand, is estimated from the number of scintillations emitted from the ZnS(Ag) sheets. Characteristics of the phoswitch-type detector were studied experimentally in some neutron fields. It was found from the experiments that the detector has an excellent property of pulse-shape discrimination between the scintillations of BC501A and the ZnS(Ag) sheets. The experimental results also indicate that the detector is capable of reproducing doses from thermal neutrons as well as neutrons with energies from one to several tens of megaelectronvolts (MeV).

  10. Improved neutron-gamma discrimination for a 6Li-glass neutron detector using digital signal analysis methods

    Science.gov (United States)

    Wang, C. L.; Riedel, R. A.

    2016-01-01

    A 6Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at Spallation Neutron Source. Traditional Pulse-Height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 104. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, six digital signal analysis methods of individual waveforms acquired from photomultiplier tubes were proposed using (i) charge integration, (ii) pulse-amplitude histograms, (iii) power spectrum analysis combined with the maximum pulse-amplitude, (iv) two event parameters (a1, b0) obtained from a Wiener filter, (v) an effective amplitude (m) obtained from an adaptive least-mean-square filter, and (vi) a cross-correlation coefficient between individual and reference waveforms. The NGD ratios are about 70 times those from the traditional PHA method. Our results indicate the NGD capabilities of neutron Anger cameras based on GS20 scintillators can be significantly improved with digital signal analysis methods.

  11. Improved neutron-gamma discrimination for a {sup 6}Li-glass neutron detector using digital signal analysis methods

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C. L., E-mail: wangc@ornl.gov; Riedel, R. A. [Instrument and Source Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2016-01-15

    A {sup 6}Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at Spallation Neutron Source. Traditional Pulse-Height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 10{sup 4}. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, six digital signal analysis methods of individual waveforms acquired from photomultiplier tubes were proposed using (i) charge integration, (ii) pulse-amplitude histograms, (iii) power spectrum analysis combined with the maximum pulse-amplitude, (iv) two event parameters (a{sub 1}, b{sub 0}) obtained from a Wiener filter, (v) an effective amplitude (m) obtained from an adaptive least-mean-square filter, and (vi) a cross-correlation coefficient between individual and reference waveforms. The NGD ratios are about 70 times those from the traditional PHA method. Our results indicate the NGD capabilities of neutron Anger cameras based on GS20 scintillators can be significantly improved with digital signal analysis methods.

  12. Progression of emphysema evaluated by MRI using hyperpolarized (3)He (HP (3)He) measurements in patients with alpha-1-antitrypsin (A1AT) deficiency compared with CT and lung function tests

    DEFF Research Database (Denmark)

    Stavngaard, T; Søgaard, L Vejby; Batz, M

    2009-01-01

    as compared to yearly decline. PURPOSE: To investigate the progression of emphysema over a period of 2 years using diffusion-weighted hyperpolarized (HP) (3)He magnetic resonance imaging (MRI) in patients with alpha-1-antitrypsin (A1AT) deficiency. MATERIAL AND METHODS: Nine patients with severe A1AT...

  13. Functions of MgH2 in hydrogen storage reactions of the 6LiBH4-CaH2 reactive hydride composite.

    Science.gov (United States)

    Zhou, Yifan; Liu, Yongfeng; Zhang, Yu; Gao, Mingxia; Pan, Hongge

    2012-08-28

    A significant improvement of hydrogen storage properties was achieved by introducing MgH(2) into the 6LiBH(4)-CaH(2) system. It was found that ~8.0 wt% of hydrogen could be reversibly stored in a 6LiBH(4)-CaH(2)-3MgH(2) composite below 400 °C and 100 bar of hydrogen pressure with a stepwise reaction, which is superior to the pristine 6LiBH(4)-CaH(2) and LiBH(4) samples. Upon dehydriding, MgH(2) first decomposed to convert to Mg and liberate hydrogen with an on-set temperature of ~290 °C. Subsequently, LiBH(4) reacted with CaH(2) to form CaB(6) and LiH in addition to further hydrogen release. Hydrogen desorption from the 6LiBH(4)-CaH(2)-3MgH(2) composite finished at ~430 °C in non-isothermal model, a 160 °C reduction relative to the 6LiBH(4)-CaH(2) sample. JMA analyses revealed that hydrogen desorption was a diffusion-controlled reaction rather than an interface reaction-controlled process. The newly produced Mg of the first-step dehydrogenation possibly acts as the heterogeneous nucleation center of the resultant products of the second-step dehydrogenation, which diminishes the energy barrier and facilitates nucleation and growth, consequently reducing the operating temperature and improving the kinetics of hydrogen storage.

  14. The CREp program, a fully parameterizable program to compute exposure ages (3He, 10Be)

    Science.gov (United States)

    Martin, L.; Blard, P. H.; Lave, J.; Delunel, R.; Balco, G.

    2015-12-01

    Over the last decades, cosmogenic exposure dating permitted major advances in Earth surface sciences, and particularly in paleoclimatology. Yet, exposure age calculation is a dense procedure. It requires numerous choices of parameterization and the use of an appropriate production rate. Nowadays, Earth surface scientists may either calculate exposure ages on their own or use the available programs. However, these programs do not offer the possibility to include all the most recent advances in Cosmic Ray Exposure (CRE) dating. Notably, they do not propose the most recent production rate datasets and they only offer few possibilities to test the impact of the atmosphere model and the geomagnetic model on the computed ages. We present the CREp program, a Matlab © code that computes CRE ages for 3He and 10Be over the last 2 million years. The CREp program includes the scaling models of Lal-Stone in the "Lal modified" version (Balco et al., 2008; Lal, 1991; Stone, 2000) and the LSD model (Lifton et al., 2014). For any of these models, CREP allows choosing between the ERA-40 atmosphere model (Uppala et al., 2005) and the standard atmosphere (National Oceanic and Atmospheric Administration, 1976). Regarding the geomagnetic database, users can opt for one of the three proposed datasets: Muscheler et al. 2005, GLOPIS-75 (Laj et al. 2004) and the geomagnetic framework proposed in the LSD model (Lifton et al., 2014). They may also import their own geomagnetic database. Importantly, the reference production rate can be chosen among a large variety of possibilities. We made an effort to propose a wide and homogenous calibration database in order to promote the use of local calibration rates: CREp includes all the calibration data published until July 2015 and will be able to access an updated online database including all the newly published production rates. This is crucial for improving the ages accuracy. Users may also choose a global production rate or use their own data

  15. Phase-contrast MRI and CFD modeling of apparent 3He gas flow in rat pulmonary airways

    Science.gov (United States)

    Minard, Kevin R.; Kuprat, Andrew P.; Kabilan, Senthil; Jacob, Richard E.; Einstein, Daniel R.; Carson, James P.; Corley, Richard A.

    2012-08-01

    Phase-contrast (PC) magnetic resonance imaging (MRI) with hyperpolarized 3He is potentially useful for developing and testing patient-specific models of pulmonary airflow. One challenge, however, is that PC-MRI provides apparent values of local 3He velocity that not only depend on actual airflow but also on gas diffusion. This not only blurs laminar flow patterns in narrow airways but also introduces anomalous airflow structure that reflects gas-wall interactions. Here, both effects are predicted in a live rat using computational fluid dynamics (CFD), and for the first time, simulated patterns of apparent 3He gas velocity are compared with in vivo PC-MRI. Results show (1) that correlations (R2) between measured and simulated airflow patterns increase from 0.23 to 0.79 simply by accounting for apparent 3He transport, and (2) that remaining differences are mainly due to uncertain airway segmentation and partial volume effects stemming from relatively coarse MRI resolution. Higher-fidelity testing of pulmonary airflow predictions should therefore be possible with future imaging improvements.

  16. A High-Pressure Polarized $^3$He Gas Target for Nuclear Physics Experiments Using A Polarized Photon Beam

    CERN Document Server

    Ye, Q; Chen, W; Gao, H; Zheng, W; Zong, X; Averett, T; Cates, G D; Tobias, W A

    2009-01-01

    Following the first experiment on three-body photodisintegration of polarized $^3$He utilizing circularly polarized photons from High Intensity Gamma Source (HI$\\gamma$S) at Duke Free Electron Laser Laboratory (DFELL), a new high-pressure polarized $^3$He target cell made of pyrex glass coated with a thin layer of sol-gel doped with aluminum nitrate nonahydrate has been built in order to reduce photon beam induced backgrounds. The target is based on the technique of spin-exchange optical pumping of hybrid rubidium and potassium and the highest polarization achieved is $\\sim$62\\% determined from both NMR-AFP and EPR polarimetry. The $X$ parameter is estimated to be $0.17\\pm0.06$ and the performance of the target is in good agreement with theoretical predictions. We also present beam test results from this new target cell and the comparison with the GE180 $^3$He target cell used previously at HI$\\gamma$S. This is the first time that sol-gel coating technique has been used in a polarized $^3$He target for nuclea...

  17. Production of residual nuclei by {sup 3}He-induced reactions on {sup 27}Al and {sup nat}Cu

    Energy Technology Data Exchange (ETDEWEB)

    Kondratyev, S.N.; Lobach, I.Yu.; Lobach, Yu.N.; Sklyarenko, V.D. [Akademyiya Nauk Ukrayini, kiev (Ukraine). Yinst. Yadernikh Doslyidzhen`

    1997-05-01

    Excitation functions have been measured by the stacked foil technique for the production of {sup 22,24}Na and {sup 57,58,60}Co, {sup 65}Zn in the interaction of {sup 3}He ions with aluminium and copper over the energy range up to 91 MeV. The measured excitation functions are suitable for monitoring beam energy and intensity. (author).

  18. Test of phi(sup 2) model predictions near the (sup 3)He liquid-gas critical point

    Science.gov (United States)

    Barmatz, M.; Zhong, F.; Hahn, I.

    2000-01-01

    NASA is supporting the development of an experiment called MISTE (Microgravity Scaling Theory Experiment) for future International Space Station mission. The main objective of this flight experiment is to perform in-situ PVT, heat capacity at constant volume, C(sub v) and chi(sub tau), measurements in the asymptotic region near the (sup 3)He liquid-gas critical point.

  19. Degassing of 3H/3He, CFCs and SF6 by denitrification: Measurements and two-phase transport simulations

    NARCIS (Netherlands)

    Visser, A.; Schaap, J.D.; Broers, H.P.; Bierkens, M.F.P.

    2009-01-01

    The production of N2 gas by denitrification may lead to the appearance of a gas phase below the water table prohibiting the conservative transport of tracer gases required for groundwater dating. We used a two-phase flow and transport model (STOMP) to study the reliability of 3H/3He, CFCs and SF6 as

  20. Investigation of isospin effects in d p → {sup 3}Heπ{sup +}π{sup -} at ANKE

    Energy Technology Data Exchange (ETDEWEB)

    Mielke, Malte; Fritzsch, Christopher; Goslawski, Paul; Khoukaz, Alfons; Papenbrock, Michael; Schroeer, Daniel; Taeschner, Alexander [Westfaelische Wilhelms-Universitaet, Muenster (Germany); Wilkin, Colin [University College London (United Kingdom); Collaboration: ANKE-Collaboration

    2014-07-01

    Two-pion production in nuclear collisions has been the subject of intensive research for more than 50 years, ever since the discovery of the so-called ABC-effect in proton-deuteron collisions. The effect appears as an enhancement at low two-pion invariant masses and is found to be dominantly in the ππ isospin I{sub ππ} = 0 channel. In the d p → {sup 3}Heπ{sup +}π{sup -} reaction, interferences of I{sub ππ} = 0 and I{sub ππ} = 1 are allowed, which permits studies on possible contributions of the Roper resonance, especially in the isovector part. These cause the {sup 3}He π{sup +} and {sup 3}He π{sup -} invariant-mass distributions to differ in shape and are therefore experimentally accessible. The high momentum resolution that is needed to quantify these differences can be achieved with the ANKE spectrometer at the COoler SYnchrotron (COSY), where data of the reaction d p → {sup 3}Heπ{sup +}π{sup -} were recorded in an excess energy range of 265 to 285 MeV. The use of kinematically complete events allows a detailed analysis of the invariant mass distributions to be made and reveals that there must be some isospin-one ππ production even for relatively low values of M{sub ππ}. Final results are presented and discussed.

  1. Multi-tracer approach (18O, 3H/3He, CFC, SF6, 35S) to find the best emergency drinking water supply, Vorarlberg, Austria

    Science.gov (United States)

    Kralik, Martin; Vergnaud, Virginie; Uriostegui, Stephanie; Esser, Bradley

    2016-04-01

    To provide an emergency drinking water supply in case of catastrophic events (regional chemical accidents, floods, earth quakes etc.), wells and springs should be known which are fed by a large reservoir. Such reservoirs provide a good filtering capacity and long Mean Residence Times (MRTs) of the raw water. Their existence allows to use these resources for longer periods excluding the danger of contamination. This provides the water authorities the necessary time to set measures to protect the general water supply. After preselection of 16 wells and springs all over the territory of the province of Vorarlberg at the western end of Austria by the local water authority, these wells and springs were measured (water temperature, electric conductivity, pH and dissolved oxygen content) and sampled monthly for δ 18O/2H measurements over the winter half-year 2013/14. At the same time the tritium concentrations of the October and March samples were measured as well. Based on the variation of the monthly on-site measurements and the δ 18O/2H results 12 wells and springs were selected for further investigations. On these sites samples for 3H/3He, CFC-11/12/113, SF6 and sulphur-35 measurements were collected in August 2014. As expected from a humid alpine area, non of the selected springs or wells showed really long MRTs. Five out of 16 investigated sites are regarded as well suited to be used as emergency water source with a range of MRTs of 9 - 30 years. Five springs and wells are regarded of limited suitability due to the shorter MRTs of 5 - 9 years. In two springs the 3H/3He method could not be applied due to He-degassing in a karst-system and during sampling. CFC and SF6 excess at some sites with anthropogenic and geogenic sources hampered the utilisation of these gases as dating tool, but they were useful as source tracers. Sulphur-35 was detected in two wells only, indicating contribution of very young water (tracers, otherwise would have supported the suitability of

  2. MeV He3/He4 isotope abundances in solar energetic particle events: SOHO/COSTEP observations

    Science.gov (United States)

    Bothmer, V.:; Sierks, H.; Böhm, E.; Kunow, H.

    2001-08-01

    We present first results based on a systematic survey of 4-41 MeV/N 3He/4He isotope abundances with ratios >0.01 detected by the COmprehensive SupraThermal and Energetic Particle analyzer (COSTEP) onboard the SOHO (SOlar and Heliospheric Observatory) spacecraft. More than about 25% of the identified events showed 3He/4He ratios in the range 0.1-1. For events with sufficiently high detector count rates the atomic mass plots can be resolved up to a time resolution of about 1 hour. These events are most suitable for comparisons with in situ solar wind plasma and magnetic field measurements and SOHO's optical white-light and extreme ultraviolet (EUV) observations of the Sun. The correlations show an association with passages of shock associated coronal mass ejections (CMEs) in the solar wind that inhibit high He/H plasma overabundances. It is likely that the CMEs have been released in strong magnetic reconfiguration processes at the solar source sites. Here we present a brief overview of such an event detected on October 30, 2000. 1. Introduction The SOHO/COSTEP instrument measures solar energetic particles (SEPs) at MeV energies in the interplanetary medium. The solid state detectors are capable to detect 3 He/4 He-enrichments at these energies (Müller-Mellin et al., 1995). Usually, the 3 He/4 He-ratio in the solar wind is at the order of 10-4 , but occasionally ratios up to about values of ~1 or even above have been observed in SEP events (e.g., Mason et al., 1999). The origin of these isotope abundances has commonly been attributed to impulsive solar flares and wave-particle interaction mechanisms (Temerin and Roth, 1992). However, fully satisfying physical explanations are still lacking. Here we present first results of a systematic survey of the He-measurements taken by COSTEP since launch in 1995 until the end of the year 2000. 2. Data For this study we have analyzed SOHO/COSTEP measurements of 4.3-40.9 MeV/N helium particles as well as COSTEP data covering

  3. Estimation of the extraterrestrial 3He and 20Ne fluxes on Earth from He and Ne systematics in marine sediments

    Science.gov (United States)

    Chavrit, Déborah; Moreira, Manuel; Moynier, Frédéric

    2016-04-01

    Sediments contain interplanetary dust particles (IDPs) carrying extraterrestrial noble gases, such as 3He, which have previously been used to estimate the IDP accretion flux over time and the duration of past environmental events. However, due to its high diffusivity, He can be lost by diffusion either due to frictional heating during entry in the atmosphere, or once it has been incorporated in the sediments. Therefore the absolute values of 3He IDP fluxes cannot be known. Due to its lower diffusivity, Ne is less likely to be lost by diffusion than He and can potentially provide an absolute IDP flux value. Here, we studied the Ne and He isotopic composition of 21 sediments of different ages (3 to 38 Myr, 56 Myr and 183 Myr) in order to better constrain the retention of 3He in such deposits. The samples are carbonates from 2 sites of the Integrated Ocean Drilling Program (IODP), which previously showed evidence of detectable extraterrestrial 3He, and from the Sancerre core in the Paris basin. The 3He/4He, 20Ne/22Ne and 21Ne/22Ne ratios of decarbonated residues vary respectively from 0.09×10-6 to 76.5×10-6, 9.54±0.08 to 11.30±0.60 and from 0.0295±0.0001 to 0.0344±0.0003. These isotopic compositions can be explained by a mixing between two terrestrial components (atmosphere and radiogenic He and nucleogenic Ne present in the terrigenous fractions) and an extraterrestrial component. The linear relationship between 20Ne/22Ne and 3He/22Ne ratios shows that the extraterrestrial component has a unique composition and is similar to the He and Ne composition of implanted solar wind. This composition is different from the individual stratospheric IDPs for which the Ne and He isotopic compositions have been measured. We suggest that this difference is due to a bias in the sampling of the individual IDPs previously analyzed toward the largest ones that are more likely to lose He during entry in the atmosphere. Our data further constrains the size of the majority of the

  4. A survey of 3He enhancements at 2–20 MeV/nucleon: Ulysses COSPIN/LET

    Directory of Open Access Journals (Sweden)

    M. Y. Hofer

    Full Text Available We present the results of a survey of enhancements in the ratio of 3He/4 He as measured by the COSPIN/LET instrument on board the Ulysses spacecraft in the energy range 2–20 MeV/n. In the context of this study, all ratios of 3He/4 He above 0.05 are considered to be enhanced compared with the solar system value of ~0.0004. Previous studies have shown that enhanced fluxes of 3He are frequently associated with small, impulsive solar flare events in which the observer is well connected to the flare site. These events also often show enrichments in heavy ion composition compared with standard coronal values. Recent attention has also focused on 3He enrichments as evidence for re-acceleration of remnant particle populations that are present in the inner heliosphere following periods of enhanced solar activity. For this study, we have examined the Ulysses data set from launch (October 1990 up to the present, representing a full solar cycle. The spatial coverage extends from 1–5.4 AU in heliocentric distance, and effectively includes the complete range of heliomagnetic latitudes from pole to pole. We have identified 12 periods of enhanced 3He/4 He, occurring at heliocentric distances out to 5 AU, and heliolatitudes up to 48°. We investigate the characteristics of the events, many of which last for several days, in order to establish possible origins.Key words. Interplanetary physics (energetic particles – Solar physics, astrophysics and astronomy (energetic particles; flares and mass ejections

  5. Search for η-mesic 4He in the dd →3He nπ0 and dd →3He pπ- reactions with the WASA-at-COSY facility

    Science.gov (United States)

    Adlarson, P.; Augustyniak, W.; Bardan, W.; Bashkanov, M.; Bergmann, F. S.; Berłowski, M.; Bhatt, H.; Bondar, A.; Büscher, M.; Calén, H.; Ciepał, I.; Clement, H.; Czerwiński, E.; Demmich, K.; Engels, R.; Erven, A.; Erven, W.; Eyrich, W.; Fedorets, P.; Föhl, K.; Fransson, K.; Goldenbaum, F.; Goswami, A.; Grigoryev, K.; Gullström, C.-O.; Heijkenskjöld, L.; Hejny, V.; Hüsken, N.; Jarczyk, L.; Johansson, T.; Kamys, B.; Kelkar, N. G.; Kemmerling, G.; Khatri, G.; Khoukaz, A.; Khreptak, O.; Kirillov, D. A.; Kistryn, S.; Kleines, H.; Kłos, B.; Krzemień, W.; Kulessa, P.; Kupść, A.; Kuzmin, A.; Lalwani, K.; Lersch, D.; Lorentz, B.; Magiera, A.; Maier, R.; Marciniewski, P.; Mariański, B.; Morsch, H.-P.; Moskal, P.; Ohm, H.; Perez del Rio, E.; Piskunov, N. M.; Prasuhn, D.; Pszczel, D.; Pysz, K.; Pyszniak, A.; Ritman, J.; Roy, A.; Rudy, Z.; Rundel, O.; Sawant, S.; Schadmand, S.; Schätti-Ozerianska, I.; Sefzick, T.; Serdyuk, V.; Shwartz, B.; Sitterberg, K.; Skorodko, T.; Skurzok, M.; Smyrski, J.; Sopov, V.; Stassen, R.; Stepaniak, J.; Stephan, E.; Sterzenbach, G.; Stockhorst, H.; Ströher, H.; Szczurek, A.; Trzciński, A.; Varma, R.; Wolke, M.; Wrońska, A.; Wüstner, P.; Yamamoto, A.; Zabierowski, J.; Zieliński, M. J.; Złomańczuk, J.; Żuprański, P.; Żurek, M.

    2017-03-01

    The search for 4He- η bound states was performed with the WASA-at-COSY facility via the measurement of the excitation function for the dd →3He nπ0 and dd →3He pπ- processes. The deuteron beam momentum was varied continuously between 2.127 GeV/c and 2.422 GeV/c, corresponding to the excess energy for the dd →4He η reaction ranging from Q = - 70 MeV to Q = 30 MeV. The luminosity was determined based on the dd →3He n reaction and the quasi-free proton-proton scattering via dd → ppnspectatornspectator reactions. The excitation functions, determined independently for the measured reactions, do not reveal a structure which could be interpreted as a narrow mesic nucleus. Therefore, the upper limits of the total cross sections for the bound state production and decay in dd →(4He- η) bound →3He nπ0 and dd →(4He- η) bound →3He pπ- processes were determined taking into account the isospin relation between the both of the considered channels. The results of the analysis depend on the assumptions of the N*(1535) momentum distribution in the anticipated mesic-4He. Assuming, as in the previous works, that this is identical with the distribution of nucleons bound with 20 MeV in 4He, we determined that (for the mesic bound state width in the range from 5 MeV to 50 MeV) the upper limits at 90% confidence level are about 3 nb and about 6 nb for nπ0 and pπ- channels, respectively. However, based on the recent theoretical findings of the N*(1535) momentum distribution in the N*-3He nucleus bound by 3.6 MeV, we find that the WASA-at-COSY detector acceptance decreases and hence the corresponding upper limits are 5 nb and 10 nb for nπ0 and pπ- channels respectively.

  6. Characterization of {sup 6}LiF:Mg,Cu,P (TLD-600 H) estimate of E, b and s parameters

    Energy Technology Data Exchange (ETDEWEB)

    Andres, P. A., E-mail: andresp@cab.cnea.gov.ar [Centro Atomico Bariloche, Division Proteccion Radiologica / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina)

    2015-10-15

    LiF:Mg,Cu,P dosemeters are useful for low-dose measurements because of its high sensitivity compared to the LiF:Mg,Ti dosemeters. {sup 7}LiF:Mg,Cu,P have been used for environmental dosimetry in Bariloche Atomic Centre for almost a decade. Since {sup 6}LiF:Mg,Cu,P dosemeters were intended to be used for X ray diagnosis dosimetry in neonatology, they had to be characterized first. The main goal of measuring and analyzing Tl glow curves is the extraction of some parameters that can be used to describe the Tl process in the material. This job focused on the estimation of the activation energy E for the Tl traps, the frequency factor s and the order of kinetics b of the Tl process. Furthermore, the most appropriate time-temperature profile (Ttp) was determined as well as the annealing temperature and time, which resulted being 240 degrees C for 10 minutes. The Ttp used was 140 degrees C for 10 seconds, a heating rate of 20/s until 240 degrees C, remaining at this temperature for 20 seconds, and then an exponential cooling until 50 degrees C. After applying the whole glow-peak method for different orders of kinetic, and the Kitis equation assuming a first order kinetics, the values obtained were: E = (1.066 ± 0.025) eV, as a weighted average of both methods, and a frequency factor s = (3.57 ± 1.56) E-10 s{sup -1} again as a weighted average of both methods. In both cases a first order kinetics (b = 1) was assumed. The dosemeters were irradiated with a calibrated {sup 137}Cs source and read with a Harshaw TLD{sup TM} Model 3500 reader resulting in a minimum detectable dose of about 20 μGy. (Author)

  7. Quasifree Lambda, Sigma^0, and Sigma^- electroproduction from 1,2H, 3,4He, and Carbon

    Energy Technology Data Exchange (ETDEWEB)

    F. Dohrmann; A. Ahmidouch; C.S. Armstrong; J. Arrington; R. Asaturyan; S. Avery; K. Bailey; H. Bitao; H. Breuer; D.S. Brown; R. Carlini; J. Cha; N. Chant; E. Christy; A. Cochran; L. Cole; J. Crowder; S. Danagoulian; M. Elaasar; R. Ent; H. Fenker; Y. Fujii; L. Gan; K. Garrow; D.F. Geesaman; P. Gueye; K. Hafidi; W. Hinton; H. Juengst; C. Keppel; Y. Liang; J.H. Liu; A. Lung; D. Mack; P. Markowitz; J. Mitchell; T. Miyoshi; H. Mkrtchyan; S.K. Mtingwa; B. Mueller; G. Niculescu; I. Niculescu; D. Potterveld; B.A. Raue; P.E. Reimer; J. Reinhold; J. Roche; M. Sarsour; Y. Sato; R.E. Segel; A. Semenov; S. Stepanyan; V. Tadevosyan; S. Tajima; L. Tang; A. Uzzle; S. Wood; H. Yamaguchi; C. Yan; L. Yuan; B. Zeidman; M. Zeier; B. Zihlmann

    2007-07-30

    Kaon electroproduction from light nuclei and hydrogen, using 1H, 2H, 3He, 4He, and Carbon targets has been measured at Jefferson Laboratory. The quasifree angular distributions of Lambda and Sigma hyperons were determined at Q^2= 0.35(GeV/c)^2 and W= 1.91GeV. Electroproduction on hydrogen was measured at the same kinematics for reference.

  8. Reactions {ital pd}{r_arrow}{sup 3}He{eta} and {ital pd}{r_arrow}{sup 3}He{pi}{sup +}{pi}{sup {minus}} near the {eta} threshold

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, B.; Boudard, A.; Fabbro, B.; Garcon, M.; Kerboul, C.; Poitou, J.; Wellers, F. [Service de Physique Nucleaire, CEA Saclay, F-91191 Gif-sur-Yvette (France); Jacobs, W.W.; Saudinos, J.; Tomasi-Gustafsson, E. [Laboratoire National Saturne, F-91191 Gif-sur-Yvette (France); Mouly, J.P. [Service d`Etudes des Detecteurs, CEA Saclay, F-91191 Gif-sur-Yvette (France); Kessler, R.S.; Nefkens, B.M.; Tippens, B. [Department of Physics, University of California, Los Angeles, California 90024 (United States); van der Schaaf, A. [Physik-Institut der Universitaet Zuerich, CH-8057 Zuerich (Switzerland); Abegg, R.; van Oers, W.T. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (CANADA); Briscoe, W.; Petrov, A. [Center for Nuclear Studies and Department of Physics, The George Washington University, Washington, D.C. 20052 (United States); Moalem, A. [Department of Physics, Ben Gurion University, Beer-Sheva 84105 (Israel)

    1996-05-01

    The reaction {ital pd}{r_arrow}{sup 3}He{eta} has been studied with the SPES2 spectrometer, for proton energies between 0.2 MeV and 11 MeV above threshold. The total cross section rises from 0.25 to 0.40 {mu}b in this region. The observed energy dependence can be attributed to the strong final state interaction. The angular distribution is nearly isotropic, consistent with {ital S} wave production. A measurement of the {ital pd}{r_arrow}{sup 3}He{pi}{sup +}{pi}{sup {minus}} cross section in the threshold region is also presented. The setup, which is capable of producing 10{sup 5} tagged {eta}/s with only a few percent background, is used to investigate rare {eta} decays. {copyright} {ital 1996 The American Physical Society.}

  9. Low-energy effective field theory of superfluid 3He-B and its gyromagnetic and Hall responses

    CERN Document Server

    Fujii, Keisuke

    2016-01-01

    The low-energy physics of a superfluid 3He-B is governed by Nambu-Goldstone bosons resulting from its characteristic symmetry breaking pattern. Here we construct an effective field theory at zero temperature consistent with all available symmetries in curved space, which are the U(1) phase x SU(2) spin x SO(3) orbital gauge invariance and the nonrelativistic general coordinate invariance, up to the next-to-leading order in a derivative expansion. The obtained low-energy effective field theory is capable of predicting gyromagnetic responses of the superfluid 3He-B, such as a magnetization generated by a rotation and an orbital angular momentum generated by a magnetic field, in a model-independent and nonperturbative way. We furthermore show that the stress tensor exhibits a dissipationless Hall viscosity with coefficients uniquely fixed by the orbital angular momentum density, which manifests itself as an elliptical polarization of sound wave with an induced transverse component.

  10. Limit on Lorentz-Invariance- and CPT-Violating Neutron Spin Interactions Using a $^3$He-$^{129}$Xe Comagnetometer

    CERN Document Server

    Allmendinger, Fabian; Heil, Werner; Karpuk, Sergej; Sobolev, Yuri

    2016-01-01

    We performed a search for a Lorentz-invariance- and CPT-violating coupling of the $^3$He and $^{129}$Xe nuclear spins to posited background fields. Our experimental approach is to measure the free precession of nuclear spin polarized $^3$He and $^{129}$Xe atoms using SQUID detectors. As the laboratory reference frame rotates with respect to distant stars, we look for a sidereal modulation of the Larmor frequencies of the co-located spin samples. As a result we obtain an upper limit on the equatorial component of the background field $\\tilde{b}^n_{\\bot}< 8.4 \\cdot 10^{-34}$ GeV (68\\% C.L.). Furthermore, this technique was modified to search for an electric dipole moment (EDM) of $^{129}$Xe.

  11. Measurements of Correlated Pair Momentum Distributions in {sup 3}He(e,e{prime}pp)n with CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Rustam Niyazov

    2003-05-01

    We have measured the {sup 3}He(e,e{prime}pp)n reaction at 2.2 and 4.4 GeV over a wide kinematic range. The kinetic energy distribution for ''fast'' nucleons (p > 250 MeV/c) peaks where two nucleons each have 20% or less and the third or ''leading'' nucleon carries most of the transferred energy. These fast nucleon pairs (both pp and pn) are back-to-back and carry very little momentum along {rvec q}, indicating that they are spectators. Experimental and theoretical evidence indicates that we have measured NN correlations in {sup 3}He(e,e{prime}pp)n by striking the third nucleon and detecting the spectator correlated pair.

  12. 186Os and 187Os enrichments and high-3He/4He sources in the Earth's mantle

    DEFF Research Database (Denmark)

    Brandon, A.D.; Graham, D.W.; Waight, Tod Earle

    2007-01-01

    . These Os isotope systematics are best explained by ancient recycled crust or melt enrichment in the mantle source region. If so, then the coupled enrichments displayed in 186Os/188Os and 187Os/188Os from lavas of other plume systems must result from an independent process, the most viable candidate...... picrites is best modeled as mixtures of 1 Ga or older ancient recycled crust mixed with primitive mantle or incompletely degassed depleted mantle isolated since 1-1.5 Ga, which preserves the high 3He/4He of the depleted mantle at the time. These mixtures create a hybrid source region that subsequently...... be interpreted as an increase in the proportion of ancient recycled crust in the upwelling plume over this time period. The positive correlation between 187Os/188Os and 3He/4He demonstrates that the Iceland lava He isotopic compositions do not result from simple melt depletion histories and consequent removal...

  13. Chlorofluorocarbons and ~3H/~3He in groundwater——Applications in tracing and dating young groundwater

    Institute of Scientific and Technical Information of China (English)

    秦大军; 王浩

    2001-01-01

    Based on the CFC concentration, the fraction of young groundwater in a mixture with old groundwater can be defined if the age of the young component is known. The authors argued that the ratio of [3HeJ/[3Ht] in a young water is independent of its mixing with old waters. Hence, the 3H-3He can be used to determine age of the young groundwater, though mixing with old ground-water may occur. CFC concentrations are susceptible to change by mixing of young and old water. The combination of CFCs and tritium/helium can provide confidential apparent age of the young groundwater and fraction of the young water in the mixture with old groundwater.

  14. Experimental study of the p d (d p )→3Heπ π reactions close to threshold

    Science.gov (United States)

    Bellemann, F.; Berg, A.; Bisplinghoff, J.; Bohlscheid, G.; Ernst, J.; Henrich, C.; Hinterberger, F.; Ibald, R.; Jahn, R.; Joosten, R.; Kilian, K.; Kozela, A.; Machner, H.; Magiera, A.; Munkel, J.; von Neumann-Cosel, P.; von Rossen, P.; Schnitker, H.; Scho, K.; Smyrski, J.; Tölle, R.; Wilkin, C.; COSY-MOMO Collaboration

    2016-09-01

    New experimental data on the p d → 3Heπ+π- reaction obtained with the COSY-MOMO detector below the three-pion threshold are presented. The reaction was also studied in inverse kinematics with a deuteron beam and the higher counting rates achieved were especially important at low excess energies. The comparison of these data with inclusive p d → 3HeX0 rates allowed estimates also to be made of π0π0 production. The results confirm our earlier findings that, close to threshold, there is no enhancement at low excitation energies in the π+π- system, where the data seem largely suppressed compared with phase space. Possible explanations for this behavior, such as strong p waves in the π+π- system or the influence of two-step processes, are explored.

  15. Non-singlet structure function of the 3He-3H system and divergence of the Gottfried integral

    CERN Document Server

    Guzey, V; Strikman, M I; Thomas, A W; Tsushima, K

    2001-01-01

    We study shadowing and antishadowing corrections to the flavor non-singlet structure function F_2(3He)-F_2(3H) and show that the difference between the one-particle density distributions of 3He and 3H plays an important role at very small x. We find that the flavor non-singlet structure function in these mirror nuclei is enhanced at small x by nuclear shadowing, which increases the nuclear Gottfried integral, integrated from 10^{-4} to 1, by 11-36 %. When integrated from zero, the Gottfried integral is divergent for these mirror nuclei. It seems likely that, as a consequence of charge symmetry breaking, this may also apply to the proton-neutron system.

  16. Differential cross sections for p + /sup 3/He scattering from 19. 5 to 47. 5 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.E.; Murdoch, B.T.; Hasell, D.K.; Sourkes, A.M.; van Oers, W.T.H.

    1980-07-01

    Differential cross sections for /sup 3/He(p,p)/sup 3/He elastic scattering have been measured at 11 energies from 19.5 to 47.5 MeV. The most forward center-of-mass angle for the angular distributions varies from 10.1 to 13.4/sup 0/, and the most backward angle varies from 163.2 to 173.4/sup 0/. The relative errors are usually less than 2%, and the scale error is 1.5%. The present data and the existing vector-analyzing power and total-reaction cross-section data are being analyzed in this energy range using the Los Alamos Scientific Laboratory R-matrix code EDA.

  17. Upgrade of the POLDI diffractometer with a ZnS(Ag)/6LiF scintillation detector read out with WLS fibers coupled to SiPMs

    OpenAIRE

    Mosset, J. -B.; Stoykov, A.; Davydov, V.; Hildebrandt, M.; Van Swygenhoven, H.; W. Wagner

    2013-01-01

    A thermal neutron detector based on ZnS(Ag)/6LiF scintillator, wavelength-shifting fibers (WLS) and silicon photomultipliers (SiPM) is under development at the Paul Scherrer Institute (PSI) for upgrading the POLDI instrument, a pulse-overlap diffractometer. The design of the detector is outlined, and the measurements performed on a single channel prototype are presented. An innovative signal processing system based on a photon counting approach is under development. Its principle of operation...

  18. Methodische und technische Weiterentwicklung der 3-He-MRT im Hinblick auf erweiterte lungendiagnostische Anwendungsmöglichkeiten

    OpenAIRE

    Hiebel, Stefan

    2007-01-01

    Die vorliegende Arbeit untersucht die Möglichkeiten und Limitierungen der MR-Lungenbildgebung mit hyperpolarisiertem 3-He bei gegenüber üblichen Magnetfeldstärken reduzierten magnetischen Führungsfeldern. Dabei werden insbesondere auch die funktionellen Bildgebungstechniken (dynamische Bildgebung, diffusionsgewichtete Bildgebung und Bestimmung des Sauerstoff-Partialdrucks) berücksichtigt. Experimentell geschieht dies durch in vivo Messungen an einem 0.1 T-Ganzkörpertomographen. Zur systema...

  19. Production of {sup 4}He, {sup 3}He, and tritium from Be irradiated in FFTF-MOTA-2B

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, L.R. [Pacific Northwest National Lab., Richland, WA (United States)

    1998-03-01

    The production of {sup 4}He, {sup 3}He, and tritium has been calculated for beryllium irradiated in the Materials Open Test Assembly (MOTA)-2B experiment in the Fast Flux Test Facility (FFTF). Reaction rates were based on adjusted neutron spectra determined from reactor dosimetry measurements at seven different elevations in the irradiation assembly. Equations are given so that gas production, dpa, and neutron fluences can be calculated for any specific elevation in the MOTA-2B assembly.

  20. Neutron interferometric measurement of the scattering length difference between the triplet and singlet states of n-$^3$He

    CERN Document Server

    Huber, M G; Chen, W C; Gentile, T R; Hussey, D S; Black, T C; Pushin, D A; Shahi, C B; Wietfeldt, F E; Yang, L

    2014-01-01

    We report a determination of the n-$^3$He scattering length difference $\\Delta b^{\\prime} = b_{1}^{\\prime}-b_{0}^{\\prime} = $ ($-5.411$ $\\pm$ $0.031$ (statistical) $\\pm$ $0.039$ (systematic)) fm between the triplet and singlet states using a neutron interferometer. This revises our previous result $\\Delta b^{\\prime} = $ (-5.610 $\\pm$ $0.027$ (statistical) $\\pm$ $0.032$ (systematic) fm obtained using the same technique in 2008. This revision is due to a re-analysis of the 2008 experiment that includes a more robust treatment of the phase shift caused by magnetic field gradients near the $^3$He cell. Furthermore, we more than doubled our original data set from 2008 by acquiring six months of additional data in 2013. Both the new data set and a re-analysis of the older data are in good agreement. Scattering lengths of low Z isotopes are valued for use in few-body nuclear effective field theories, provide important tests of modern nuclear potential models and in the case of $^3$He aid in the interpretation of neu...

  1. The 2H Electric Dipole Moment in a Separable Potential Approach

    Directory of Open Access Journals (Sweden)

    Afnan I.R.

    2010-04-01

    Full Text Available Measurement of the electric dipole moment (EDM of 2H or of 3He may well come prior to the coveted measurement of the neutron EDM. Exact model calculations for the deuteron are feasible, and we explore here the model dependence of such deuteron EDM calculations. We investigate in a separable potential approach the relationship of the full model calculation to the plane wave approximation, correct an error in an early potential model result, and examine the tensor force aspects of the model results as well as the effect of the short range repulsion found in the realistic, contemporary potential model calculations of Liu and Timmermans. We conclude that, because one-pion exchange dominates the EDM calculation, separable potential model calculations should provide an adequate picture of the 2H EDM until better than 10% measurements are achieved.

  2. Using 3He/4He to Map the flow of the Samoan-Plume into the Lau Basin

    Science.gov (United States)

    Price, A.; Jackson, M. G.; Hall, P. S.; Sinton, J. M.; Kurz, M. D.

    2011-12-01

    Understanding how the upper mantle flows beneath oceanic lithosphere is crucial to understanding mantle melting, the distribution of geochemical reservoirs, and movement of plate tectonics. Spatial variations in the geochemistry of igneous rocks can provide an understanding of flow in the upper mantle. Numerous geochemical and geophysical anomalies within the northern portion of the Lau basin--the presence of high 3He/4He (up to 28 times atmospheric), latitudinal gradients in trace element and isotopic (Sr-Nd-Pb) enrichment, and trench parallel shear wave splitting near the Tonga arc--have been attributed to the southward flow of mantle material from the nearby Samoan hotspot. The Samoan plume is located only 200 km east of the northern terminus of the Tonga trench. North of the terminus, the Pacific plate "tears" and, instead of subducting into the trench, continues to the West. To the South of the terminus, the Pacific plate subducts into the Tonga Trench. The resulting tear generated a "slab window", allowing the Samoan mantle to flow southward beneath the Vitiaz lineament and penetrate into the shallow mantle of the Lau Basin. The juxtaposition of the Samoan hotspot and the Tonga Trench create a unique setting in which the southward flow of the distinctive high 3He/4He Samoan plume mantle can be readily detected in the Lau Basin. High 3He/4He ratios (up to 28.1 Ra) have been reported in a swath within the northern Lau Basin, which drop rapidly to both the South (~400km south of Peggy ridge) and East (Lupton, 2009) of this narrow incursion. It was suggested that the 3He/ 4He would also decline to the west, creating a "finger-like" corridor of Samoan Plume (Turner & Hawkesworth ,1998). However, such a model is not constrained, as 3He/4He ratios have not been reported in the region to the West of the infiltrating plume. Does the Samoan plume material extend broadly to the west, or is it confined to a narrow "finger-like" corridor in the North Lau Basin? We present

  3. Intense laser induced field ionization of C2H2, C2H4,and C2H6

    Institute of Scientific and Technical Information of China (English)

    GAO Lirong; JI Na; XONG Yijia; TANG Xiaoping; KONG Fan'ao

    2003-01-01

    Using HOMO Field Ionization Model, the tunneling probabilities and the theoretical threshold intensities of the field ionizations of acetylene, ethylene, and ethane in intense laser field are calculated. C2H2, C2H4, and C2H6 were irradiated by 800 nm, 100 fs laser pulses with the intensity range of 1013-1014 W/cm2. A TOF-mass spectrometer was coupled to the laser system and used to experimentally investigate the field ionization of these molecules. The experimental ionization threshold intensities are obtained. The calculating results of the three molecules agree well with the experimental results, indicating that HOMO Field Ionization Model is valid for the ionization of polyatomic molecules in intense laser field.

  4. THz spectroscopy of D2H+

    Science.gov (United States)

    Yu, S.; Pearson, J. C.; Amano, T.; Matsushima, F.

    2017-01-01

    We extended the measurements of the rotational transitions of D2H+ up to 3 THz by using the JPL frequency multiplier chains and a TuFIR system at Toyama. D2H+ was generated in an extended negative glow discharge cell cooled to liquid nitrogen temperature. We observed five new THz lines. All the available rotational transition frequencies together with the combination differences derived from the three fundamental bands were subject to least square analysis to determine the molecular constants. New THz measurements are definitely useful for better characterization of spectroscopic properties. The improved molecular constants provide better predictions of other unobserved rotational transitions.

  5. Measurement of pretzelosity asymmetry of charged pion production in Semi-Inclusive Deep Inelastic Scattering on a polarized $^3$He target

    CERN Document Server

    Zhang, Y; Allada, K; Dutta, C; Huang, J; Katich, J; Wang, Y; Aniol, K; Annand, J R M; Averett, T; Benmokhtar, F; Bertozzi, W; Bradshaw, P C; Bosted, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J -P; Chen, W; Chirapatpimol, K; Chudakov, E; Cisbani, E; Cornejo, J C; Cusanno, F; Dalton, M M; Deconinck, W; de Jager, C W; De Leo, R; Deng, X; Deur, A; Ding, H; Dolph, P A M; Dutta, D; Fassi, L El; Frullani, S; Gao, H; Garibaldi, F; Gaskell, D; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Guo, L; Hamilton, D; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, M; Ibrahim, H F; Iodice, M; Jiang, X; Jin, G; Jones, M K; Kelleher, A; Kim, W; Kolarkar, A; Korsch, W; LeRose, J J; Li, X; Li, Y; Lindgren, R; Liyanage, N; Long, E; Lu, H -J; Margaziotis, D J; Markowitz, P; Marrone, S; McNulty, D; Meziani, Z -E; Michaels, R; Moffit, B; Camacho, C Muñoz; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Oh, Y; Osipenko, M; Parno, D; Peng, J C; Phillips, S K; Posik, M; Puckett, A J R; Qiang, Y; Rakhman, A; Ransome, R D; Riordan, S; Saha, A; Sawatzky, B; Schulte, E; Shahinyan, A; Shabestari, M H; Sirca, S; Stepanyan, S; Subedi, R; Sulkosky, V; Tang, L -G; Tobias, W A; Urciuoli, G M; Vilardi, I; Wang, K; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y -W; Zhao, B; Zheng, X; Zhu, L; Zhu, X; Zong, X

    2013-01-01

    An experiment to measure single-spin asymmetries in semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized $^3$He target was performed at Jefferson Lab in the kinematic region of $0.163$He, which can be expressed as the convolution of the $h^\\perp_{1T}$ transverse momentum dependent distribution functions and the Collins fragmentation functions in the leading order, were measured for the first time. Using the effective polarization approximation, we extracted the corresponding neutron asymmetries from the measured $^3$He asymmetries and cross-section ratios between the proton and $^3$He. Our results show that for both $\\pi^{\\pm}$ on $^3$He and on the neutron the pretzelosity asymmetries are consistent with zero within experimental uncertainties.

  6. Analytical continuous slowing down model for nuclear reaction cross-section measurements by exploitation of stopping for projectile energy scanning and results for 13C(3He,α)12C and 13C(3He,p)15N

    Science.gov (United States)

    Möller, S.

    2017-03-01

    Ion beam analysis is a set of precise, calibration free and non-destructive methods for determining surface-near concentrations of potentially all elements and isotopes in a single measurement. For determination of concentrations the reaction cross-section of the projectile with the targets has to be known, in general at the primary beam energy and all energies below. To reduce the experimental effort of cross-section measurements a new method is presented here. The method is based on the projectile energy reduction when passing matter of thick targets. The continuous slowing down approximation is used to determine cross-sections from a thick target at projectile energies below the primary energy by backward calculation of the measured product spectra. Results for 12C(3He,p)14N below 4.5 MeV are in rough agreement with literature data and reproduce the measured spectra. New data for reactions of 3He with 13C are acquired using the new technique. The applied approximations and further applications are discussed.

  7. Contactless friction and the {sup 3}He-{sup 4}He dimer. Studies with the atomic-beam spin-echo spectrometer; Kontaktlose Reibung und das {sup 3}He-{sup 4}He-Dimer. Untersuchungen mit dem Atomstrahlspinechospektrometer

    Energy Technology Data Exchange (ETDEWEB)

    Janke, Matthias

    2016-04-20

    In this thesis the time of flight resolved atomic beam spin echo method (SEToF) is applied to a {sup 3}He-beam for the first time and studied systematically. This method is shown to be superior to the usual atomic beam spin echo technique. With SEToF it is possible to almost completely remove unpolarized background and to reach a beam polarisation close to 100%. The SEToF technique is shown to be crucial for the first experimental proof of the existence of the {sup 3}He-{sup 4}He dimer. This dimer is the weakest bound van-der-Waals-molecule known to date. Furthermore, a drag force between an atom and a dielectric surface is detected originating from the fluctuating dipole moment of the atom. Not only the measured friction coefficients match their theoretical predictions perfectly, but our data also shows the correct temperature dependence. A great many technological renewals and improvements were installed in the apparatus during this thesis work. They have become necessary or sensible due to the relocation of the physics institute. A few of them are documented and motivated in this thesis.

  8. Understanding complex exposure history of Mount Hampton, West Antarctica using cosmogenic 3He, 21Ne and 10Be in olivine

    Science.gov (United States)

    Carracedo, Ana; Rodes, Angel; Stuart, Finlay; Smellie, John

    2016-04-01

    Combining stable and radioactive cosmogenic nuclides is an established tool for revealing the complexities of long-term landscape development. To date most studies have concentrated on 21Ne and 10Be in quartz. We have combined different chemical protocols for extraction of cosmogenic 10Be from olivine, and measured concentrations in olivine from lherzolite xenoliths from the peak of Mount Hampton (~3,200 m), an 11 Ma shield volcano on the West Antarctic rift flank. We combine this data with cosmogenic 3He (and 21Ne) in the olivines in order to unravel the long-term environmental history of the region. The mean 3He/21Ne ratio (1.98 ± 0.22) is consistent with the theoretical value and previous determinations. 10Be/3He ratios (0.012 to 0.018) are significantly lower than the instantaneous production ratio (~0.045). The data are consistent with 1-3 Ma of burial. The altitude of the volcano rules out over-topping of the peak by the West Antarctic Ice Sheet only possible burial could be generated by the growth of an ice cap although this contradicts the absence of evidence for ice cover. The 3He-10Be data can also be generated during episodic erosion of the volcanic ash over the last few million years. The data requires a minimum depth of 1 to 2.5 m for the samples during a minimum age of 5 Ma and maximum long-term erosion rate of ~0.5 m/Ma with at least one erosive episode reflecting short-term erosion rate of ~7 m/Ma that would have brought the samples into the surface during the last ~350 ka. Erosion in this type of landscape could be related to interglacial periods where cryostatic erosion can occur generating an increase in the erosion rate. This study shows that episodic erosion can produce stable-radioactive cosmogenic isotope systematics that are similar to those generated by exposure-burial cycles.

  9. Cosmic ray exposure dating with in situ produced cosmogenic 3He: results from young Hawaiian lava flows

    Science.gov (United States)

    Kurz, M.D.; Colodner, D.; Trull, T.W.; Moore, R.B.; O'Brien, K.

    1990-01-01

    In an effort to determine the in situ production rate of spallation-produced cosmogenic 3He, and evaluate its use as a surface exposure chronometer, we have measured cosmogenic helium contents in a suite of Hawaiian radiocarbon-dated lava flows. The lava flows, ranging in age from 600 to 13,000 years, were collected from Hualalai and Mauna Loa volcanoes on the island of Hawaii. Because cosmic ray surface-exposure dating requires the complete absence of erosion or soil cover, these lava flows were selected specifically for this purpose. The 3He production rate, measured within olivine phenocrysts, was found to vary significantly, ranging from 47 to 150 atoms g-1 yr-1 (normalized to sea level). Although there is considerable scatter in the data, the samples younger than 10,000 years are well-preserved and exposed, and the production rate variations are therefore not related to erosion or soil cover. Data averaged over the past 2000 years indicate a sea-level 3He production rate of 125 ?? 30 atoms g-1 yr-1, which agrees well with previous estimates. The longer record suggests a minimum in sea level normalized 3He production rate between 2000 and 7000 years (55 ?? 15 atoms g-1 yr-1), as compared to samples younger than 2000 years (125 ?? 30 atoms g-1 yr-1), and those between 7000 and 10,000 years (127 ?? 19 atoms g-1 yr-1). The minimum in production rate is similar in age to that which would be produced by variations in geomagnetic field strength, as indicated by archeomagnetic data. However, the production rate variations (a factor of 2.3 ?? 0.8) are poorly determined due to the large uncertainties in the youngest samples and questions of surface preservation for the older samples. Calculations using the atmospheric production model of O'Brien (1979) [35], and the method of Lal and Peters (1967) [11], predict smaller production rate variations for similar variation in dipole moment (a factor of 1.15-1.65). Because the production rate variations, archeomagnetic data

  10. Measurement of the 3He(e,e'p)pn reaction at high missing energies and momenta

    Energy Technology Data Exchange (ETDEWEB)

    F. Benmokhtar; M. M. Rvachev; E. Penel-Nottaris

    2004-09-01

    Results of the Jefferson Lab Hall A quasielastic 3He(e,e'p)pn measurements are presented. These measurements were performed at fixed transferred momentum and energy, q = 1502 MeV/c and omega = 840 MeV, respectively, for missing momenta {+-} up to 1 GeV/c and missing energies in the continuum region, up to pion threshold; this kinematic coverage is much more extensive than that of any previous experiment. The cross section data are presented along with the effective momentum density distribution and compared to theoretical models.

  11. A study of the 90Zr( 3He, t) reaction at 43.4 MeV

    Science.gov (United States)

    Fields, C. A.; Ristinen, R. A.; Samuelson, L. E.; Smith, P. A.

    1982-09-01

    Low-lying states of 90Nb have been investigated using the 90Zr( 3He, t) reaction at 43.4 MeV. In addition to the well-known π( P{1}/{2}) v (g {9}/{2}) -1and π(g {9}/{2}) v (g {9}/{2}) -1 particle-hole states, many other levels were observed. The angular distributions for the ( g{9}/{2}) 2 states are investigated using DWBA calculations using collective, OPEP, and independent tensor and spin-isospin potentials.

  12. Validity of apparent diffusion coefficient hyperpolarized 3He-MRI using MSCT and pulmonary function tests as references

    DEFF Research Database (Denmark)

    Diaz, Sandra; Casselbrant, Ingrid; Piitulainen, Eeva

    2008-01-01

    from MSCT. Both mean ADC and MSCT data were compared to PFT, especially percent of predicted diffusing capacity of carbon monoxide (%predicted DLCO), using Pearson's correlation test. RESULTS: Mean ADC and standard deviation values were 0.392+/-0.119 cm(2)/s for the established emphysema group and 0....... Correlations between mean ADC and EI and 15th percentile were both r=0.90 and for MLD r=0.59. There was higher correlation between mean ADC and %predicted DLCO (r=0.90) than between EI and %predicted DLCO (r=0.76). CONCLUSION: HP (3)He-MRI correlates well with density measurements from MSCT and agrees better...

  13. Universal temperature dependence, flux extinction, and the role of 3He impurities in superfluid mass transport through solid 4He.

    Science.gov (United States)

    Vekhov, Ye; Mullin, W J; Hallock, R B

    2014-07-18

    The mass flux, F, carried by as-grown solid (4)He in the range 25.6-26.3 bar rises with falling temperature, and at a concentration-dependent temperature, T(d), the flux decreases sharply within a few mK. We study F as a function of (3)He impurity concentration, χ. We find that T(d) is an increasing function of increasing χ. At temperatures above T(d) the flux has a universal temperature dependence and the flux terminates in a narrow window near a characteristic temperature T(h) ≈ 625 mK, which is independent of χ.

  14. On the use of a (252Cf-3He) assembly for landmine detection by the neutron back-scattering method.

    Science.gov (United States)

    Elsheikh, N; Viesti, G; ElAgib, I; Habbani, F

    2012-04-01

    Experiments were carried out to optimize the performance of the neutron back-scattering (NBS) technique in landmine detection using an assembly consisting of three different layers placed above a (252)Cf neuron source, producing about 10(4)s(-1), in conjunction with a (3)He detector. The assembly was optimized experimentally. The selected assembly configuration was then examined against different (252)Cf stand-off distances and mine burial depths using dummy landmines. Furthermore, Monte Carlo simulations were performed to study the effect of the shield when a (252)Cf source in the range 10(4)-10(7)s(-1) was employed, and to optimize the geometry for future prototypes.

  15. Study of the d(p,{\\gamma})3He Reaction at Ultralow Energies using a Zirconium Deuteride Target

    CERN Document Server

    Bystritsky, V M; Krylov, A R; Parzhitskii, S S; Philippov, A V; Dudkin, G N; Nechaev, B A; Padalko, V N; Penkov, F M; Tuleushev, Yu Zh; Filipowicz, M; Bystritskii, Vit M; Gazi, S; Huran, J

    2013-01-01

    The mechanism for the d(p,{\\gamma})3He reaction in the region of ultralow proton-deuteron collision energies (6.67

  16. Precise Measurement of Magnetic Field Gradients from Free Spin Precession Signals of $^{3}$He and $^{129}$Xe Magnetometers

    CERN Document Server

    Allmendinger, F; Doll, M; Grasdijk, O; Heil, W; Jungmann, K; Karpuk, S; Krause, H -J; Offenhäusser, A; Repetto, M; Schmidt, U; Sobolev, Yu; Tullney, K; Willmann, L; Zimmer, S

    2016-01-01

    We report on precise measurements of magnetic field gradients extracted from transverse relaxation rates of precessing spin samples. The experimental approach is based on the free precession of gaseous, nuclear spin polarized $^3$He and $^{129}$Xe atoms in a spherical cell inside a magnetic guiding field of about 400 nT using LT$_C$ SQUIDs as low-noise magnetic flux detectors. The transverse relaxation rates of both spin species are simultaneously monitored as magnetic field gradients are varied. For transverse relaxation times reaching 100 h, the residual longitudinal field gradient across the spin sample could be deduced to be$|\\vec{\

  17. A self-contained 3He melting curve thermometer for dissemination of the PLTS-2000 temperature scale

    Science.gov (United States)

    Shvarts, Dm; Adams, A.; Lusher, C. P.; Körber, R.; Cowan, B. P.; Noonan, P.; Saunders, J.; Mikheev, V. A.

    2004-01-01

    We describe a self-contained 3He melting curve thermometer (MCT), which is compact and easy to operate and makes a reliable tool for the direct dissemination of the new provisional low-temperature scale, PLTS-2000. It is based on a cylindrical pressure gauge and uses a tunnel diode oscillator circuit for capacitive read-out. The gas-handling system uses a set of relief valves and an electronic pressure sensor, enabling the thermometer to be fully automated, including the calibration procedure. The performance of the MCT was evaluated by comparison with a current-sensing noise thermometer in the temperature range from 20 to 700 mK.

  18. Validity of apparent diffusion coefficient hyperpolarized 3He-MRI using MSCT and pulmonary function tests as references

    DEFF Research Database (Denmark)

    Diaz, Sandra; Casselbrant, Ingrid; Piitulainen, Eeva;

    2008-01-01

    PURPOSE: To compare apparent diffusion coefficient (ADC) measurements from hyperpolarized (HP) helium ((3)He)-magnetic resonance imaging (MRI) with quantitative data from multislice Computed Tomography (CT) (MSCT) of the whole lungs and pulmonary function tests (PFT). MATERIALS AND METHODS: Twenty...... from MSCT. Both mean ADC and MSCT data were compared to PFT, especially percent of predicted diffusing capacity of carbon monoxide (%predicted DLCO), using Pearson's correlation test. RESULTS: Mean ADC and standard deviation values were 0.392+/-0.119 cm(2)/s for the established emphysema group and 0...

  19. Absence of spin dependence in the final state interaction of the d(pol) p --> 3He eta reaction

    CERN Document Server

    Papenbrock, M; Burmeister, I; Chiladze, D; Dymov, S; Fritzsch, C; Gebel, R; Goslawski, P; Hartmann, M; Kacharava, A; Keshelashvili, I; Khoukaz, A; Kulessa, P; Kulikov, A; Lorentz, B; Mchedlishvili, D; Mersmann, T; Merzliakov, S; Mielke, M; Mikirtychiants, S; Ohm, H; Prasuhn, D; Rathmann, F; Rausmann, T; Serdyuk, V; Ströher, H; Täschner, A; Trusov, S; Valdau, Y; Wilkin, C

    2014-01-01

    The deuteron tensor analysing power t_{20} of the d(pol) p --> 3He eta reaction has been measured at the COSY-ANKE facility in small steps in excess energy Q up to Q = 11 MeV. Despite the square of the production amplitude varying by over a factor of five through this range, t_{20} shows little or no energy dependence. This is evidence that the final state interaction causing the energy variation is not influenced by the spin configuration in the entrance channel. The weak angular dependence observed for t_{20} provides useful insight into the amplitude structure near threshold.

  20. Precision Measurement of the Spin Dependent Asymmetry in the Threshold Region of {sup 3}He(e,e{prime})

    Energy Technology Data Exchange (ETDEWEB)

    F. Xiong; Dipangkar Dutta; W. Xu (MIT; LNS); Bryon Anderson; L. Auberbach; Todd Averett; William Bertozzi; Timothy Black; John Calarco; Larry Cardman; Gorden Cates; Zhengwei Chai; Jian-ping Chen; Seonho Choi; Eugene Chudakov; Steve Churchwell; G.S. Corrado; C. Crawford; Dan Dale; Alexandre Deur; Pibaro Djawotho; Bradley Filippone; Mike Finn; Haiyan Gao; Ron Gilman; Alexander Glamazdin; Charles Glashausser; W. Glockle; J. Golak; Javier Gomez; Victor Gorbenko; Jens-Ole Hansen; F. William Hersman; Douglas W. Higinbotham; Richard Holmes; C.R. Howell; E. Hughes; B. Humensky; Sebastian Incerti; Kees de Jager; J.Steffen Jensen; Xiangdong Jiang; C.E. Jones; Mark Jones; R. Kahl; H. Kamada; A. Kievsky; Ioannis Kominis; Wolfgang Korsch; Kevin Kramer; Gerfried Kumbartzki; Michael Kuss; E. Lakuriqi; Meme Liang; Nilanga Liyanage; John LeRose; Sergey Malov; Dimitri Margaziotis; Jeffrey Martin; Kathy McCormick; Robert McKeown; K. McIlhany; Zein-Eddine Meziani; Robert Michaels; G.W. Miller; E. Pace; T. Pavlin; Gerassimos G. Petratos; R.I. Pomatsalyuk; D. Pripstein; David Prout; Ronald Ransome; Yves Roblin; Marat Rvachev; Arun Saha; G. Salme; M. Schnee; Taeksu Shin; Karl Slifer; Paul Souder; Steffen Strauch; Riad Suleiman; M. Sutter; Bryan Tipton; Luminita Todor; M. Viviani; B. Vlahovic; J. Watson; C.F. Williamson; H. Witala; Bogdan B. Wojtsekhowski; J. Yeh; P. Zolnierczuk

    2001-12-10

    We present the first precision measurement of the spin-dependent asymmetry in the threshold region of {sup 3}He(e,e{prime}) at Q{sup 2}-values of 0.1 and 0.2 (GeV/c){sup 2}. The agreement between the data and non-relativistic Faddeev calculations which include both final-state interactions (FSI) and meson-exchange currents (MEC) effects is very good at Q{sup 2} = 0.1 (GeV/c){sup 2}, while a small discrepancy at Q{sup 2} = 0.2 (GeV/c){sup 2} is observed.

  1. Prerainbow Oscillations in $^3$He Scattering from the Hoyle State of $^{12}$c and Alpha Particle Condensation

    CERN Document Server

    Ohkubo, S

    2011-01-01

    $^3$He+$^{12}$C scattering is studied in a coupled channel method by using a double folding model with microscopic wave functions of $^{12}$C. Experimental angular distributions in elastic and inelastic scattering to the $2^+$ (4.44 MeV), 0$^+_2$ (7.65 MeV) and 3$^-$ (9.63 MeV) states of $^{12}$C are well reproduced. It is found that the Airy minimum of the prerainbow oscillations for the Hoyle state is considerably shifted to a larger angle due to its dilute density distribution compared with that of the normal ground state in agreement with the idea of $\\alpha$ particle condensation.

  2. Single Spin Asymmetries of Inclusive Hadrons Produced in Electron Scattering from a Transversely Polarized $^3$He Target

    CERN Document Server

    Allada, K; Aniol, K; Annand, J R M; Averett, T; Benmokhtar, F; Bertozzi, W; Bradshaw, P C; Bosted, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J -P; Chen, W; Chirapatpimol, K; Chudakov, E; Cisbani, E; Cornejo, J C; Cusanno, F; Dalton, M; Deconinck, W; de Jager, C W; De Leo, R; Deng, X; Deur, A; Ding, H; Dolph, P A M; Dutta, C; Dutta, D; Fassi, L El; Frullani, S; Gao, H; Garibaldi, F; Gaskell, D; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Guo, L; Hamilton, D; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, J; Huang, M; Ibrahim, H F; Iodice, M; Jiang, X; Jin, G; Jones, M K; Katich, J; Kelleher, A; Kim, W; Kolarkar, A; Korsch, W; LeRose, J J; Li, X; Li, Y; Lindgren, R; Liyanage, N; Long, E; Lu, H -J; Margaziotis, D J; Markowitz, P; Marrone, S; McNulty, D; Meziani, Z -E; Michaels, R; Moffit, B; Camacho, C Munoz; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Oh, Y; Osipenko, M; Parno, D; Peng, J -C; Phillips, S K; Posik, M; Puckett, A J R; Qian, X; Qiang, Y; Rakhman, A; Ransome, R; Riordan, S; Saha, A; Sawatzky, B; Schulte, E; Shahinyan, A; Shabestari, M H; Sirca, S; Stepanyan, S; Subedi, R; Sulkosky, V; Tang, L -G; Tobias, A; Urciuoli, G M; Vilardi, I; Wang, K; Wang, Y; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y; Zhang, Y -W; Zhao, B; Zheng, X; Zhu, L; Zhu, X; Zong, X

    2013-01-01

    We report the first measurement of target single-spin asymmetries (A$_N$) in the inclusive hadron production reaction, $e $+$ ^3\\text{He}^{\\uparrow}\\rightarrow h+X$, using a transversely polarized $^3$He target at an electron-nucleon center-of-mass energy $\\sqrt{s}$=3.45 GeV. The experiment was conducted at Jefferson Lab in Hall A using a 5.9-GeV electron beam. Three types of hadrons ($\\pi^{\\pm}$, $\\text{K}^{\\pm}$ and proton) were detected with an average momentum $$=2.35 GeV/c, and an average transverse momentum $$=0.64 GeV/c. The observed asymmetry strongly depends on the type of hadron. A positive asymmetry is observed for $\\pi^+$ and $\\text{K}^+$. A negative asymmetry is observed for $\\pi^{-}$. The magnitudes of the asymmetries follow $|A^{\\pi^-}| < |A^{\\pi^+}| < |A^{K^+}|$. The K$^{-}$ and proton asymmetries are consistent with zero within the experimental uncertainties. The $\\pi^{+}$ and $\\pi^{-}$ asymmetries measured for the $^3$He target and extracted for neutrons are opposite in sign with a sma...

  3. Measurement of double-polarization asymmetries in the quasielastic (3)He[→](e[→],e(')d) process.

    Science.gov (United States)

    Mihovilovič, M; Jin, G; Long, E; Zhang, Y-W; Allada, K; Anderson, B; Annand, J R M; Averett, T; Boeglin, W; Bradshaw, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J P; Chudakov, E; De Leo, R; Deng, X; Deltuva, A; Deur, A; Dutta, C; El Fassi, L; Flay, D; Frullani, S; Garibaldi, F; Gao, H; Gilad, S; Gilman, R; Glamazdin, O; Golak, J; Golge, S; Gomez, J; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, J; Ibrahim, H; de Jager, C W; Jensen, E; Jiang, X; Jones, M; Kang, H; Katich, J; Khanal, H P; Kievsky, A; King, P; Korsch, W; LeRose, J; Lindgren, R; Lu, H-J; Luo, W; Marcucci, L E; Markowitz, P; Meziane, M; Michaels, R; Moffit, B; Monaghan, P; Muangma, N; Nanda, S; Norum, B E; Pan, K; Parno, D; Piasetzky, E; Posik, M; Punjabi, V; Puckett, A J R; Qian, X; Qiang, Y; Qui, X; Riordan, S; Saha, A; Sauer, P U; Sawatzky, B; Schiavilla, R; Schoenrock, B; Shabestari, M; Shahinyan, A; Širca, S; Skibiński, R; John, J St; Subedi, R; Sulkosky, V; Tobias, W A; Tireman, W; Urciuoli, G M; Viviani, M; Wang, D; Wang, K; Wang, Y; Watson, J; Wojtsekhowski, B; Witała, H; Ye, Z; Zhan, X; Zhang, Y; Zheng, X; Zhao, B; Zhu, L

    2014-12-05

    We present a precise measurement of double-polarization asymmetries in the ^{3}He[over →](e[over →],e^{'}d) reaction. This particular process is a uniquely sensitive probe of hadron dynamics in ^{3}He and the structure of the underlying electromagnetic currents. The measurements have been performed in and around quasielastic kinematics at Q^{2}=0.25(GeV/c)^{2} for missing momenta up to 270  MeV/c. The asymmetries are in fair agreement with the state-of-the-art calculations in terms of their functional dependencies on p_{m} and ω, but are systematically offset. Beyond the region of the quasielastic peak, the discrepancies become even more pronounced. Thus, our measurements have been able to reveal deficiencies in the most sophisticated calculations of the three-body nuclear system, and indicate that further refinement in the treatment of their two-and/or three-body dynamics is required.

  4. Observations of Heavy Element Abundances over a Broad Energy Range in 3He-rich Solar Energetic Particle Events

    Science.gov (United States)

    Wiedenbeck, M. E.; Mason, G. M.; Cohen, C. M.; Leske, R. A.; Cummings, A. C.; Dwyer, J. R.; Mazur, J. E.; Mewaldt, R. A.; Stone, E. C.; von Rosenvinge, T. T.

    2006-05-01

    During the maximum of solar cycle 23 a number of 3He-rich solar energetic particle (SEP) events with measurable intensities of heavy elements (Z≥6) at energies >10 MeV/nuc were observed with instrumentation on the Advanced Composition Explorer (ACE) spacecraft. This represents a relatively small fraction of all the 3He-rich SEP events that were detected since heavy-ion intensities at these energies were frequently too low to be measured. Using data from two ACE instruments (SIS covering ~10--60 MeV/nuc and ULEIS ~0.2--1 MeV/nuc) we have investigated heavy element abundances over a broad energy range in this special set of events. We report the average abundance ratios and the correlations between different ratios in the two energy intervals. Furthermore we compare the results from the two different energy ranges, both statistically and on an event-by-event basis. In addition, we compare the statistical properties observed in the SIS and ULEIS data sets with previously-published results obtained at intermediate energies (~1--3 MeV/nuc) from instruments on ISEE-3 during the maximum of solar cycle 21 (Mason et al. 1986, Reames et al. 1994).

  5. Testing for spin dependence in the final state interaction of the reaction vector dp → {sup 3}Heη

    Energy Technology Data Exchange (ETDEWEB)

    Papenbrock, Michael; Khoukaz, Alfons; Fritzsch, Christopher; Goslawski, Paul; Mielke, Malte; Schroeer, Daniel; Taeschner, Alexander [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet, 48149 Muenster (Germany); Wilkin, Colin [Physics and Astronomy Department, UCL, London WC1E 6BT (United Kingdom); Collaboration: ANKE-Collaboration

    2014-07-01

    The dp → {sup 3}Heη reaction is known for the unexpected energy dependence of its total cross section, which rises rapidly to its plateau value within the first 1 MeV of excess energy Q. This behaviour has been ascribed to a strong final state interaction and may indicate a quasi-bound η {sup 3}He state. In order to investigate the possibility of spin-dependent contributions to the total cross section, the deuteron tensor analysing power t{sub 20} has been measured in an excess energy range from Q=0 MeV up to above Q 10 MeV at the COSY-ANKE spectrometer. This allows one to compare the magnitudes of the contributions from the two spin configurations in the entrance channel with the strong variation seen in the average production amplitude. Furthermore, a weak angular dependence of t{sub 20} was also extracted and this provides insight into the structure of the production amplitude close to threshold. Final results are presented and discussed.

  6. Precise tests of fundamental symmetries at low energies using a {sup 3}He-{sup 129}Xe comagnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Allmendinger, Fabian

    2015-01-21

    Effects of theories beyond the Standard Model would become directly apparent at high energies, which are probably out of reach for colliders. As an alternative, low-energy high-precision measurements of quantities are performed, looking for deviations from the Standard Model (SM) predictions. In this case: Firstly, a small amount of the large effects of quantum gravity at the Planck scale should remain at low energies, which is tested by looking for Lorentz invariance violation in the neutron sector. Secondly, new sources of CP-violation would cause permanent electric dipole moments (EDMs)of particles that are many orders of magnitude larger than the EDMs predicted by the SM. The experimental approach is to measure the free precession of nuclear spin polarized {sup 3}He and {sup 129}Xe atoms in a homogeneous magnetic guiding field of about 400 nT using LT{sub C} SQUIDs as low-noise magnetic flux detectors. This dissertation reports on the search for a CPT and Lorentz invariance violating coupling of the {sup 3}He and {sup 129}Xe nuclear spins to posited background fields. An upper limit on the equatorial component of the background field interacting with the spin of the bound neutron b{sup n} {sub perpendicular} {sub to} <8.4.10{sup -34} GeV (68% C.L.) was obtained. Furthermore, the technical developments and preparations for measurements of the {sup 129}Xe EDM are described.

  7. Cross-section measurements for {sup 239}Pu(n,f) and {sup 6}Li(n,{alpha}) with a lead slowing-down spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Rochman, D. [National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)]. E-mail: drochman@bnl.gov; Haight, R.C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: haight@lanl.gov; O' Donnell, J.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: odonnell@lanl.gov; Wender, S.A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: wender@lanl.gov; Vieira, D.J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: vieira@lanl.gov; Bond, E.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: bond@lanl.gov; Bredeweg, T.A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: toddb@lanl.gov; Wilhelmy, J.B. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: j_wilhelmy@lanl.gov; Granier, T. [Commissariat a l' Energie Atomique, 91680 Bruyeres-le-Chatel (France)]. E-mail: granier@cea.fr; Ethvignot, T. [Commissariat a l' Energie Atomique, 91680 Bruyeres-le-Chatel (France)]. E-mail: ethvignot@cea.fr; Petit, M. [Commissariat a l' Energie Atomique, 91680 Bruyeres-le-Chatel (France)]. E-mail: petit@cea.fr; Danon, Y. [Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)]. E-mail: danony@rpi.edu; Romano, C. [Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)]. E-mail: romanc2@rpi.edu

    2006-08-01

    We present fission cross-section measurements with {approx}10ng of {sup 239}Pu performed using the LANSCE Lead Slowing-Down Spectrometer. Results of Li6(n,{alpha}) measurements with a sample size of 760ng of {sup 6}Li are also reported. This technical achievement demonstrates the feasibility of measuring neutron-induced fission cross-section on samples with 10ng of fissile actinides that are available on ultra-small quantities. Furthermore, results on neutron-induced alpha emission show that measurements for astrophysics purposes are feasible with the LSDS.

  8. Cross-section measurements for 239Pu(n,f) and 6Li(n, α) with a lead slowing-down spectrometer

    Science.gov (United States)

    Rochman, D.; Haight, R. C.; O'Donnell, J. M.; Wender, S. A.; Vieira, D. J.; Bond, E. M.; Bredeweg, T. A.; Wilhelmy, J. B.; Granier, T.; Ethvignot, T.; Petit, M.; Danon, Y.; Romano, C.

    2006-08-01

    We present fission cross-section measurements with ˜10 ng of 239Pu performed using the LANSCE Lead Slowing-Down Spectrometer. Results of Li6(n,α) measurements with a sample size of 760 ng of 6Li are also reported. This technical achievement demonstrates the feasibility of measuring neutron-induced fission cross-section on samples with 10 ng of fissile actinides that are available on ultra-small quantities. Furthermore, results on neutron-induced alpha emission show that measurements for astrophysics purposes are feasible with the LSDS.

  9. Measurements of double-differential neutron emission cross sections of {sup 6}Li and {sup 7}Li for 18 MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Ibaraki, Masanobu; Baba, Mamoru; Matsuyama, Shigeo; Sanami, Toshiya; Win, T.; Miura, Takako; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

    1997-03-01

    Double-differential neutron emission cross sections of {sup 6}Li and {sup 7}Li were measured for 18 MeV neutrons at Tohoku University 4.5 MV Dynamitron facility. Neutron emission spectra were obtained down to 1 MeV at 13 angles with energy resolution good enough to separate discrete levels. A care was taken to eliminate the sample-dependent background due to parasitic neutrons. Experimental results were in fair agreement with the JENDL-3.2 data and a simple model considering a three-body breakup process and discrete level excitations. (author)

  10. Digital signal processing for a thermal neutron detector using ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs

    OpenAIRE

    Mosset, J. -B.; Stoykov, A.; Greuter, U.; Hildebrandt, M.; Schlumpf, N.

    2015-01-01

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC^4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC^4 filter has been emulated digitally. The dete...

  11. Search for $^6_\\Lambda$H hypernucleus by the $^6$Li$(\\pi^-,K^+)$ reaction at $p_{\\pi^-}$ = 1.2 GeV/$c$

    CERN Document Server

    Sugimura, H; Ahn, J K; Ajimura, S; Akazawa, Y; Amano, N; Aoki, K; Bhang, H C; Chiga, N; Endo, M; Evtoukhovitch, P; Feliciello, A; Fujioka, H; Fukuda, T; Hasegawa, S; Hayakawa, S; Honda, R; Hosomi, K; Hwang, S H; Ichikawa, Y; Igarashi, Y; Imai, K; Ishibashi, N; Iwasaki, R; Joo, C W; Kiuchi, R; Lee, J K; Lee, J Y; Matsuda, K; Matsumoto, Y; Matsuoka, K; Miwa, K; Mizoi, Y; Moritsu, M; Nagae, T; Nagamiya, S; Nakagawa, M; Naruki, M; Noumi, H; Ota, R; Roy, B J; Saha, P K; Sakaguchi, A; Sako, H; Samanta, C; Samoilov, V; Sasaki, Y; Sato, S; Sekimoto, M; Shimizu, Y; Shiozaki, T; Shirotori, K; Soyama, T; Takahashi, T; Takahashi, T N; Tamura, H; Tanabe, K; Tanaka, T; Tanida, K; Tokiyasu, A O; Tsamalaidze, Z; Ukai, M; Yamamoto, T O; Yamamoto, Y; Yang, S B; Yoshida, K

    2014-01-01

    We have carried out an experiment to search for a neutron-rich hypernucleus, $^6_{\\Lambda}$H, by the $^6$Li($\\pi^-,K^+$) reaction at $p_{\\pi^-}$ =1.2 GeV/$c$. The obtained missing mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the $^6_{\\Lambda}$H hypernucleus neither below nor above the $^4_{\\Lambda}$H$+2n$ particle decay threshold. An upper limit of the production cross section for the bound $^6_{\\Lambda}$H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level.

  12. $\\Sigma^- p$ emission rates in $K^-$ absorptions at rest on $^6$Li, $^7$Li, $^{9}$Be, $^{13}$C and $^{16}$O

    CERN Document Server

    Agnello, M; Bertani, M; Bonomi, G; Botta, E; Bregant, M; Bressani, T; Bufalino, S; Busso, L; Calvo, D; Camerini, P; Dalena, B; De Mori, F; D'Erasmo, G; Feliciello, A; Filippi, A; Fiore, E M; Fontana, A; Fujioka, H; Genova, P; Gianotti, P; Grion, N; Lucherini, V; Marcello, S; Morra, O; Nagae, T; Outa, H; Pantaleo, A; Paticchio, V; Piano, S; Rui, R; Simonetti, G; Wheadon, R; Zenoni, A

    2015-01-01

    An experimental study of the $K^-_{stop}A\\rightarrow \\Sigma^- p A'$ reaction on $A=^6$Li, $^7$Li, $^9$Be, $^{13}$C and $^{16}$O $p$-shell nuclei is presented. The data were collected by the FINUDA spectrometer operating at the DA$\\Phi$NE $\\phi$-factory (LNF-INFN, Italy). Emission rates for the reaction in the mentioned nuclei are measured and compared with the few existing data. The spectra of several observables are discussed; indications of Quasi-Free absorptions by a $(np)$ pair embedded in the $A$ nucleus can be obtained from the study of the missing mass distributions.

  13. All-optical production of dual Bose-Einstein condensates of paired fermions and bosons with 6Li and 7Li

    Science.gov (United States)

    Ikemachi, Takuya; Ito, Aki; Aratake, Yukihito; Chen, Yiping; Koashi, Masato; Kuwata-Gonokami, Makoto; Horikoshi, Munekazu

    2017-01-01

    We report the first all-optical production of dual Bose-Einstein condensates (BECs) of paired 6Li (fermion) and one spin state of 7Li (boson) at the magnetic field where the s-wave interactions between fermions are resonant. Fermions are cooled efficiently by evaporative cooling and they serve as coolant for bosons. As a result, the dual condensates can be achieved by using a simple experimental apparatus and procedures, as in the case of the all-optical production of a single BEC. We show that the all-optical method enables us to realize variety of ultracold Bose-Fermi mixtures.

  14. Breakup coupling effects on near-barrier inelastic scattering of the weakly bound {sup 6}Li projectile on a {sup 144}Sm target

    Energy Technology Data Exchange (ETDEWEB)

    Woodard, A.E., E-mail: awoodard@nd.edu [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Figueira, J.M. [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, C1033AAJ Ciudad de Buenos Aires (Argentina); Otomar, D.R. [Instituto de Fisica, Universidade Federal Fluminense, Gragoata, Niteroi, R. J., 24210-340 (Brazil); Fernandez Niello, J.O. [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, C1033AAJ Ciudad de Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad de San Martin, B1650BWA San Martin, Buenos Aires (Argentina); Lubian, J. [Instituto de Fisica, Universidade Federal Fluminense, Gragoata, Niteroi, R. J., 24210-340 (Brazil)

    2012-01-01

    Angular distributions for the inelastic scattering of the weakly bound {sup 6}Li nucleus from a {sup 144}Sm target (associated with the contributions of both the 2{sub 1}{sup +} and 3{sub 1}{sup -144}Sm excited states together) were measured at bombarding energies close to the Coulomb barrier. The experimental data were compared with expected results based on continuum discretized coupled-channel (CDCC) calculations. The results confirm that it is essential to include continuum-continuum couplings to reproduce the experimental data. The analysis demonstrates that inelastic scattering data can be a critical tool in testing full CDCC calculations involving weakly bound nuclei.

  15. Digital signal processing for a thermal neutron detector using ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs

    Science.gov (United States)

    Mosset, J.-B.; Stoykov, A.; Greuter, U.; Hildebrandt, M.; Schlumpf, N.

    2016-07-01

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC4 filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach.

  16. Digital signal processing for a thermal neutron detector using ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs

    CERN Document Server

    Mosset, J -B; Greuter, U; Hildebrandt, M; Schlumpf, N

    2015-01-01

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC^4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC^4 filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach.

  17. Study of the excited {Delta} resonance ways of decay in {sup 4}He and other nuclei with the ({sup 3}He,T) reaction at 2 GeV; Etude des voies de decroissance de la resonance {Delta} excitee dans l`{sup 4}He et d`autres noyaux par la reaction ({sup 3}He,T) a 2 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Tarle-Rousteau, S.

    1995-05-10

    This thesis describes the ({sup 3}He,t) experiment carried out at 2 GeV at the Saturne National Laboratory (CEA Saclay, France) on {sup 1}H, {sup 2}H, {sup 4}He, {sup 12}C and {sup 208}Pb targets. The charged particles (pions and/or protons) from the {Delta} resonance deexcitation are detected in coincidence with triton using the Diogene large angle detector. New informations are obtained on the ways of {Delta} resonance decay in nuclei. Three modes of decay are investigated: the quasi-free decay, the {Delta}N into NN absorption and the coherent pions production. Modifications of {Delta} resonance properties in nuclei with respect to those of free {Delta} are analysed using the experimental results about pions diffusion, photons absorption, charge exchange reaction and {Delta}-hole model conclusions. The quasi-deuteron absorption process on {sup 4}He is studied using a Monte-Carlo simulation. Coherent pions production is also analysed in detail on {sup 4}He and {sup 12}C target nuclei. The process is very sensitive to {Delta}-hole correlations involved in the longitudinal spin canal which shifts the nucleus response in the {Delta} resonance region towards the low transferred energies. (J.S.). 85 refs., 72 figs., 10 tabs., 1 annexe.

  18. Production of $^3$He in Rocks by Reactions Induced by Particles of the Nuclear-Active and Muon Components of Cosmic Rays: Geological and Petrological Implications

    CERN Document Server

    Nesterenok, A V

    2016-01-01

    The paper presents data on the production of the $^3$He nuclide in rocks under the effect of cosmic-ray particles. The origin of the nuclide in the ground in neutron- and proton-induced spallation reactions, reactions induced by high-energy muons, and negative muon capture reactions is analyzed. The cross sections of reactions producing $^3$He and $^3$H are calculated by means of numerical simulations with the GEANT4 simulation toolkit. The production rate of the $^3$He nuclide in the ground is evaluated for the average level of solar activity at high geomagnetic latitudes and at sea level. It is proved that the production of $^3$He in near-surface ground layers by spallation reactions induced by cosmic-ray protons may be approximately 10% of the total production rate of cosmogenic $^3$He. At depths of 10-50 m.w.e., the accumulation of $^3$He is significantly contributed by reactions induced by cosmic-ray muons. Data presented in the paper make it possible to calculate the accumulation rate of $^3$He in a roc...

  19. LETTER: Study of combined NBI and ICRF enhancement of the D-3He fusion yield with a Fokker-Planck code

    Science.gov (United States)

    Azoulay, M.; George, M. A.; Burger, A.; Collins, W. E.; Silberman, E.

    A two-dimensional bounce averaged Fokker-Planck code is used to study the fusion yield and the wave absorption by residual hydrogen ions in higher harmonic ICRF heating of D (120 keV) and 3He (80 keV) beams in the JT-60U tokamak. Both for the fourth harmonic resonance of 3He (ω = 4ωc3He(0), which is accompanied by the third harmonic resonance of hydrogen (ω = 3ωcH) at the low field side, and for the third harmonic resonance of 3He (ω = 4ωcD(0) = 3ωc3He(0)) = 2ωcH(0)), a few per cent of hydrogen ions are found to absorb a large fraction of the ICRF power and to degrade the fusion output power. In the latter case, D beam acceleration due to the fourth harmonic resonance in the 3He(D) regime can enhance the fusion yield more effectively. A discussion is given of the effect of D beam acceleration due to the fifth harmonic resonance (ω = 5ωcD) at the high field side in the case of ω = 4ωc3He(0) and of the optimization of the fusion yield in the case of lower electron density and higher electron temperature

  20. Characterization of detectors of neutrons from B+ZnS (Ag) as an alternative to {sup 3}He detectors; Caracterizacion de detectores de neutrones de B+ZnS(Ag) como alternativa a los detectores de {sup 3}He

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan A.; Suarez, Maria J.; Pujol, Luis, E-mail: juanatonio.gonzalez@upm.es, E-mail: mriajose.suarez@upm.es, E-mail: luis.pujol@upm.es [Universidad Politecnica de Madrid (UPM), Madrid (Spain). E.T.S.I. Caminos Canales y Puertos; Lorente, Alfredo; Gallego, Eduardo, E-mail: alfredo.lorente@upm.es, E-mail: eduardo.gallego@upm.es [Universidad Politecnica de Madrid (Spain). E.T.S.I. Industriales

    2013-07-01

    The objective of this paper is to present the progress made in the design of prototypes for dynamic detection of neutron detectors based on scintillation of B + ZnS (Ag), which can replace existing {sup 3}He detectors for the detection of illicit traffic of radioactive material and special nuclear material. These detectors B + ZnS (Ag) can be used, together with gamma detectors, PVT and NaI (Tl) also developed in the UPM. Two neutron detectors of different shapes and sizes were characterized using two neutron sources of {sup 241}Am + Be. Were determined depth, overall efficiency, intrinsic efficiency and limit of detection. The results of these tests allow to verify that: 1) two cylindrical detectors B + ZnS (Ag) of 5x68 cm, or 4x15x132 cm rectangular detector can replace the cylindrical detector of 5x180 cm {sup 3}He currently employed in the arcades. 2) the dynamic detection limit obtained is less than 20000 neutrons per second, when the sample becomes 2 m to 2m/s, with a probability of having no false positive or negative of the 99.99% 3) digital electronics eliminates interference from gamma emissions samples when their dose rate in the neutron detector is 65 {mu}Sv/h in less than factor 10 - 8, and keeps its detection limit and 4) two cylindrical detectors with two moderators of different thickness, of 25 to 50 mm of high density polyethylene, allow to measure the average energy of the neutrons.

  1. Measurement of the deuteron tensor polarization at the {sup 3}He{yields}d+p vertex up to internal momenta of 0.43 GeV/c

    Energy Technology Data Exchange (ETDEWEB)

    Sitnik, I.M.; Perdrisat, C.F.; Tomasi-Gustafsson, E.; Azhgirey, L.S.; Ball, J.; Bimbot, L.; Bisson, Y.; Boivin, M.; Borzunov, Yu.T.; Boyard, J.L.; Courtat, Ph.; Gacougnolle, R.; Garcon, M.; Golovanov, L.B.; Hennino, T.; Jones, M.; Kirillov, D.A.; Kunne, R.; Malinina, L.V.; Nedev, S.; Piskunov, N.M.; Punjabi, V.; Rekalo, M.P.; Sans, J.L.; Skowron, R.; Strokovsky, E.A.; Yonnet, J

    2000-01-31

    The tensor polarization of deuterons, {rho}{sub 20}, emitted at zero degree in the {sup 1}H({sup 3}He, d-{r_reversible})X reaction, was measured at the Saturne National Laboratory in Saclay, using the SPES4 magnetic channel and the HYPOM polarimeter. The momentum of the detected deuterons was kept fixed at 3.77 GeV/c, while the momentum of the {sup 3}He beam was varied from 5.66 to 4.60 GeV/c; this provided a range of internal momenta of a deuteron in {sup 3}He, k, from 0 to 0.43 GeV/c.

  2. Measurement of the ω Meson Polarization in the pd → 3He ω Reaction at 1360 and 1450 MeV

    Science.gov (United States)

    Schönning, K.; Calén, H.; Fransson, K.; Höistad, B.; Johansson, T.; Kupsć, A.; Wilkin, C.; Złomańczuk, J.

    The tensor polarization of ω mesons produced in the pd → 3Heω reaction has been measured at two energies near threshold. The 3He nuclei were detected in coincidence with the π0π+π- or π0γ decay products of the ω. The ω mesons are found to be unpolarised, which is in complete contrast to the case of ϕ-meson production from the corresponding reaction pd → 3Heϕ. This brings into question the applicability of the Okubo-Zweig-Iizuka rule when comparing the production of vector mesons in low energy hadronic reactions.

  3. Measurement of differential cross sections and cross sections of the 6Li(n, t)4He reaction in the 1-2MeV energy range%1-2 MeV能区6Li(n,t)4He反应微分截面与截面的实验测量

    Institute of Scientific and Technical Information of China (English)

    张国辉; 陈金象; 唐国有; Gledenov Yu M; Sedysheva M; Khuukhenkhuu G

    2006-01-01

    利用屏栅电离室对1.05、1.54及2.25 MeV中子6Li(n,t)4He反应的微分截面与截面进行了实验测量.采用氚固体靶的T(p,n)3He反应产生准单能中子,用相对效率已知的BF3长中子管和238U裂变片相结合来测定绝对中子通量.将测量结果与已有数据进行了比较,1-2 MeV能区6Li(n,t)4He反应截面的分歧在一定程度上得到了澄清.

  4. Natural Abundance 17O, 6Li NMR and Molecular Modeling Studies of the Solvation Structures of Lithium bis(fluorosulfonyl)imide/1,2-dimethoxyethane Liquid Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Chuan; Hu, Mary Y.; Borodin, Oleg; Qian, Jiangfeng; Qin, Zhaohai; Zhang, Jiguang; Hu, Jian Z.

    2016-03-01

    Natural abundance 17O and 6Li NMR experiments, quantum chemistry and molecular dynamics studies were employed to investigate the solvation structures of Li+ at various concentrations of LiFSI in DME electrolytes in an effort to solve this puzzle. It was found that the chemical shifts of both 17O and 6Li changed with the concentration of LiFSI, indicating the changes of solvation structures with concentration. For the quantum chemistry calculations, the coordinated cluster LiFSI(DME)2 forms at first, and its relative ratio increases with increasing LiFSI concentration to 1 M. Then the solvation structure LiFSI(DME) become the dominant component. As a result, the coordination of forming contact ion pairs between Li+ and FSI- ion increases, but the association between Li+ and DME molecule decreases. Furthermore, at LiFSI concentration of 4 M the solvation structures associated with Li+(FSI-)2(DME), Li+2(FSI-)(DME)4 and (LiFSI)2(DME)3 become the dominant components. For the molecular dynamics simulation, with increasing concentration, the association between DME and Li+ decreases, and the coordinated number of FSI- increases, which is in perfect accord with the DFT results. These results provide more insight on the fundamental mechanism on the very high CE of Li deposition in these electrolytes, especially at high current density conditions.

  5. Parsec-scale Variations in the 7Li i/6Li i Isotope Ratio Toward IC 348 and the Perseus OB 2 Association

    Science.gov (United States)

    Knauth, D. C.; Taylor, C. J.; Ritchey, A. M.; Federman, S. R.; Lambert, D. L.

    2017-01-01

    Measurements of the lithium isotopic ratio in the diffuse interstellar medium from high-resolution spectra of the Li i λ6708 resonance doublet have now been reported for a number of lines of sight. The majority of the results for the 7Li/6Li ratio are similar to the solar system ratio of 12.2, but the line of sight toward o Per, a star near the star-forming region IC 348, gave a ratio of about two, the expected value for gas exposed to spallation and fusion reactions driven by cosmic rays. To examine the association of IC 348 with cosmic rays more closely, we measured the lithium isotopic ratio for lines of sight to three stars within a few parsecs of o Per. One star, HD 281159, has 7Li/6Li ≃ 2 confirming production by cosmic rays. The lithium isotopic ratio toward o Per and HD 281159 together with published analyses of the chemistry of interstellar diatomic molecules suggest that the superbubble surrounding IC 348 is the source of the cosmic rays. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

  6. Simultaneous sub-Doppler laser cooling of fermionic $^6$Li and $^{40}$K on the D$_1$ line: Theory and Experiment

    CERN Document Server

    Sievers, Franz; Kretzschmar, Norman; Fernandes, Diogo Rio; Suchet, Daniel; Rabinovic, Michael; Parker, Colin V; Khaykovich, Lev; Salomon, Christophe; Chevy, Frédéric

    2014-01-01

    We report on simultaneous sub-Doppler laser cooling of fermionic $^6$Li and $^{40}$K using the D$_1$ optical transitions. We compare experimental results to a numerical simulation of the cooling process applying a semi-classical Monte Carlo wavefunction method. The simulation takes into account the three dimensional optical molasses setup and the dipole interaction between atoms and the bichromatic light field driving the D$_1$ transitions. We discuss the physical mechanisms at play, we identify the important role of coherences between the ground state hyperfine levels and compare D$_1$ and D$_2$ sub-Doppler cooling. In 5 ms, the D$_1$ molasses phase largely reduces the temperature for both $^6$Li and $^{40}$K at the same time, with a final temperature of 44 $\\mu$K and 11 $\\mu$K, respectively. For both species this leads to a phase-space density close to $10^{-4}$. These conditions are well suited to directly load an optical or magnetic trap for efficient evaporative cooling to quantum degeneracy.

  7. Simultaneous measurement of angular distribution of elastic scattering for {sup 6}Li, {sup 7}Be, and {sup 8}B in {sup 58}Ni; Medida simultanea de Distribuciones Angulares de Dispersion Elastica para {sup 6}Li, {sup 7}Be, y {sup 8}B en {sup 58}Ni

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz S, A. [Facultad de Ciencias, UAEM, Toluca, Estado de Mexico (Mexico); Martinez Q, E.; Aguilera R, E.F.; Murillo O, G.; Lizcano C, D.; Gomez C, A. [Departamento de Aceleradores, ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2007-07-01

    The experimental angular distributions of elastic scattering for the projectiles {sup 6}Li, {sup 7}Be, {sup 8}B in {sup 58}Ni were obtained. Using the Optical model with a Woods-Saxon potential form, as much for the real part as for the imaginary one, an adjustment to the experimental data varying only the depth of the imaginary part of the potential is made. A comparison of the results obtained for each projectile is made. (Author)

  8. The reaction d-vector p{yields}{sup 3}He{pi}{sup 0} near threshold

    Energy Technology Data Exchange (ETDEWEB)

    Nikulin, V.N. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)]|[Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Boudard, A.; Fabbro, B.; Garcon, M.; Mayer, B. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Clajus, M.; Kessler, R.S.; Nefkens, B.M.K. [California Univ., Los Angeles, CA (United States). Dept. of Physics; Lytkin, L.K. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)]|[Joint Inst. for Nuclear Research, Dubna (Russian Federation); Plouin, F. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)] [and others

    1996-06-01

    Angular distributions for the differential cross section and three deuteron analyzing powers iT{sub 11}, T{sub 20} and T{sub 22} of the reaction d-vector p {yields} {sup 3}He{pi}{sup 0} have been measured over the whole angular domain at 20 energies close to threshold (0.03 < T{sub {pi}}{sup cm} < 10.2 MeV). The differential cross section and tensor analyzing power T{sub 20} both show strong variation in energy and angle due to interference between S and P-wave pion production, whereas iT{sub 11} and T{sub 22} remain consistent with zero over the whole experimental range. (author). 11 refs.; Submitted to Physical Review, C (US).

  9. Bogolyubov-normal interaction and calculation of thermal conductivity of superfluid A{sub 1}-{sup 3}He

    Energy Technology Data Exchange (ETDEWEB)

    Afzali, R.; Ebrahimian, N. [Department of Physics, Faculty of Science, University of Isfahan, Isfahan 81744 (Iran)

    2006-09-15

    The diffusive thermal conductivity tensor of the A {sub 1}-phase of superfluid {sup 3}He at low temperatures and melting pressure are calculated by s-p approximation, by using the Boltzmann equation approach. We obtain that the elements of the diffusive thermal conductivities, K{sub xx}, K{sub yy}, and K{sub zz}, are proportional to T {sup -1}. Then we compare the results of this paper and our results of thermal conductivity based on Pfitzner procedure. Temperature dependence of both results is equal but numerical coefficients of them are little different. Also we show that Boguliubov-normal interaction is important in comparison to other interactions. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. On the extraction of weak transition strengths via the (3He,t) reaction at 420 MeV

    CERN Document Server

    Zegers, R G T; Akimune, H; Austin, Sam M; Berg, A M van den; Brown, B A; Fujita, Y; Fujiwara, M; Galès, S; Guess, C J; Harakeh, M N; Hashimoto, H; Hatanaka, K; Hayami, R; Hitt, G W; Howard, M E; Itoh, M; Kawabata, T; Kawase, K; Kinoshita, M; Matsubara, M; Nakanishi, K; Nakayama, S; Okumura, S; Ohta, T; Sakemi, Y; Shimbara, Y; Shimizu, Y; Scholl, C; Simenel, C; Tameshige, Y; Tamii, A; Uchida, M; Yamagata, T; Yosoi, M

    2007-01-01

    Differential cross sections for transitions of known weak strength were measured with the (3He,t) reaction at 420 MeV on targets of 12C, 13C, 18O, 26Mg, 58Ni, 60Ni, 90Zr, 118Sn, 120Sn and 208Pb. Using this data, it is shown the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via beta-decay strengths. Although theoretical calculations in distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions.

  11. Nuclear structure studies of 125Te with (n,γ), (d,p) and ( 3He,α) reactions

    Science.gov (United States)

    Honzátko, J.; Tomandl, I.; Bondarenko, V.; Bucurescu, D.; von Egidy, T.; Ott, J.; Schauer, W.; Wirth, H.-F.; Doll, C.; Gollwitzer, A.; Graw, G.; Hertenberger, R.; Valnion, B. D.

    1999-01-01

    Levels in 125Te were investigated in the range up to 3.3 MeV excitation energy by the (n,γ), (d,p) and ( 3He,α) reactions. Over 160 levels and about 360 γ-transitions were established, most for the first time. The states below 2.3 MeV with the most complete spectroscopic information were interpreted in terms of the interacting boson-fermion model (IBFM). Unitary treatment of both positive- and negative-parity states is achieved with the same model parameter close to the intermediate case between O(6) and U(5) limits. Excitation energies, electromagnetic transition rates, γ-branchings and spectroscopic factors are discussed in connection with the possible structures. A family of low-spin negative-parity states has been identified and understood by the IBFM proving their antialigned origin.

  12. An ultra compact on-beam 3He polarizer for separation of incoherent background in high Q-range SANS

    CERN Document Server

    Babcock, Earl; Salhi, Zahir

    2012-01-01

    Incoherent background can create an intrinsic problem for standard small angle neutron scattering measurements. Biological samples contain hydrogen which is a strong incoherent scatterer thus creating an intrinsic source of background that makes determination of the coherent scattering parameters difficult in special situations. This can especially be true for the Q-range from around 0.1-0.5 {\\AA}-1 where improper knowledge of the background level can lead to ambiguity in determination of the samples structure parameters. Polarization analysis is a way of removing this ambiguity by allowing one to distinguish the coherent from incoherent scattering, even when the coherent scattering is only a small fraction of the total scattered intensity. 3He spin filters are ideal for accomplishing this task because they permit the analysis of large area and large divergence scattered neutron beams without adding to detector background or changing the prorogation of the scatter neutron beam. This rapid note describes a des...

  13. Observation of quasi-fast diffusion process in sup 3 He- sup 4 He solid solutions near BCC-HCP

    CERN Document Server

    Mikhin, N P; Rudavskij, E Y

    2001-01-01

    By means of pulsed NMR one investigated into diffusion processes i sup 3 He dilute solid solution in sup 4 He at the BCC-HCP phase equilibrium line and in a melting-point curve. The applied techniques of the spin echo enabled to separate contributions made by all co-existing phases. It is determined that alongside with the contributions relevant to the equilibrium phases a secondary diffusion process characterized by anomalously high value of the diffusion coefficient manifests itself. It is shown to be close to the value of diffusion coefficient for liquid helium while diffusion is a spatially restricted one. One assumes that the observed effect may be associated with occurrence of liquid drops in the BCC-HCP transition process

  14. Radiation-damping effects in a birdcage resonator with hyperpolarised 3He gas NMR at 1.5 T.

    Science.gov (United States)

    Teh, Kevin; de Zanche, Nicola; Wild, Jim M

    2007-03-01

    The presence and diagnosis of radiation damping could have major implications in NMR experiments with hyperpolarised gases, where accurate knowledge of the flip angle is imperative. In this work radiation damping was observed and investigated in a low-pass birdcage resonator (Q=250) with samples of hyperpolarised 3He at 1.5 T. With an initially highly polarised (P=38%) sample of 3He in a spherical cell, the observed FID had a distorted line shape with a spectral line width that was three times that of the same sample in a virtually depolarised state (1 Hz line width for Pradiation damping. With highly polarised samples, significant radiation damping was observed and the effect was a lower than expected rate of depletion of M0 in RF flip angle calibration experiments, which led to significant underestimate of the RF flip angle. To our knowledge this is the first report of radiation damping in a birdcage resonator with samples hyperpolarised or otherwise. Experimental observation of radiation damping could be used as means of measuring coil efficiency as an alternative to the geometrical filling factor (eta) the definition of which is open to question for a birdcage resonator. Estimates of the birdcage filling factor from the measured damping time constants (eta(RD)=0.4%) are compared to those derived from electromagnetic energy ratios (eta(E)=1.6%) and metallic sphere frequency shift methods (eta(fs)=1.4%). These figures are much lower than the simple volume geometrical upper limit of eta(v)=3.7% derived from the ratio of cell volume to total coil volume (shield included). The physical explanation for this shortfall is that the bulk of the magnetic energy stored in the birdcage is spatially distributed predominantly between the rungs and the shield, and not in the coil centre where the sample is placed and where the B1+ field has its highest spatial homogeneity.

  15. A robust protocol for regional evaluation of methacholine challenge in mouse models of allergic asthma using hyperpolarized 3He MRI.

    Science.gov (United States)

    Thomas, Abraham C; Potts, Erin N; Chen, Ben T; Slipetz, Deborah M; Foster, W Michael; Driehuys, Bastiaan

    2009-06-01

    Hyperpolarized (HP) (3)He magnetic resonance imaging has been recently used to produce high-resolution images of pulmonary ventilation after methacholine (MCh) challenge in mouse models of allergic inflammation. This capability presents an opportunity to gain new insights about these models and to more sensitively evaluate new drug treatments in the pre-clinical setting. In the current study, we present our initial experience using two-dimensional (2D), time-resolved (3)He MRI of MCh challenge-induced airways hyperreactivity (AHR) to compare ovalbumin-sensitized and challenged (N = 8) mice to controls (N = 8). Imaging demonstrated that ovalbumin-sensitized and challenged animals exhibited many large ventilation defects even prior to MCh challenge (four out of eight) compared to no defects in the control animals. Additionally, the ovalbumin-sensitized and challenged animals experienced a greater number of ventilation defects (4.5 +/- 0.4) following MCh infusion than did controls (3.3 +/- 0.6). However, due to variability in MCh delivery that was specific to the small animal MRI environment, the difference in mean defect number was not statistically significant. These findings are reviewed in detail and a comprehensive solution to the variability problem is presented that has greatly enhanced the magnitude and reproducibility of the MCh response. This has permitted us to develop a new imaging protocol consisting of a baseline 3D image, a time-resolved 2D series during MCh challenge, and a post-MCh 3D image that reveals persistent ventilation defects.

  16. Dating buried glacier ice using cosmogenic 3He in surface clasts: Theory and application to Mullins Glacier, Antarctica

    Science.gov (United States)

    Mackay, Sean L.; Marchant, David R.

    2016-05-01

    We develop a modeling framework to describe the accumulation of terrestrial cosmogenic 3He in Antarctic debris-covered glaciers. The framework helps quantify the expected range in cosmogenic-nuclide inventories for measured clasts at the surface of supraglacial debris. We first delineate the physical factors that impact clast movement within, and on top of, debris-covered glaciers, including the effects of (1) ice ablation, (2) erosion at the debris surface, and (3) stochastic geomorphic processes that impact clast movement within and on top of supraglacial debris; we then explicitly calculate the impact of each process in altering the total inventory of cosmogenic nuclides in surface clasts. Assuming basic elements of ice-dynamics and debris entrainment are known, the model results provide an estimate for the total accumulation of cosmogenic nuclides, as well as the expected range in nuclide inventories, for any clast at the surface of debris-covered glaciers. Because the values are quantified, the approach can be applied to help evaluate the robustness of existing and future cosmogenic datasets applied to these systems. As a test, we applied our model framework towards Mullins Glacier, a cold-based debris-covered alpine glacier in the Dry Valleys of Antarctica. Our simulated values for cosmogenic-nuclide inventories compare well with those previously measured from fifteen surface cobbles along Mullins Glacier (3He), both in terms of expected ranges and absolute values, and suggest that our model framework adequately incorporates most of the complicating factors that impact cosmogenic datasets for cold-based, debris-covered glaciers. Relating these cosmogenic-nuclide inventories to ice ages, the results show that ice within Mullins Glacier increases non-linearly, ranging from 12 ka to ∼220 ka in areas of active flow, to ≫1.6 Ma in areas of slow-moving-to-stagnant ice.

  17. Geostatistical Analysis of Tritium, 3H/3He Age and Noble Gas Derived Parameters in California Groundwater

    Science.gov (United States)

    Visser, A.; Singleton, M. J.; Moran, J. E.; Fram, M. S.; Kulongoski, J. T.; Esser, B. K.

    2014-12-01

    Key characteristics of California groundwater systems related to aquifer vulnerability, sustainability, recharge locations and mechanisms, and anthropogenic impact on recharge, are revealed in a spatial geostatistical analysis of the data set of tritium, dissolved noble gas and helium isotope analyses collected for the California State Water Resources Control Board's Groundwater Ambient Monitoring and Assessment (GAMA) and California Aquifer Susceptibility (CAS) programs. Over 4,000 tritium and noble gas analyses are available from wells across California. 25% of the analyzed samples contained less than 1 pCi/L indicating recharge occurred before 1950. The correlation length of tritium concentration is 120 km. Nearly 50% of the wells show a significant component of terrigenic helium. Over 50% of these samples show a terrigenic helium isotope ratio (Rter) that is significantly higher than the radiogenic helium isotope ratio (Rrad = 2×10-8). Rter values of more than three times the atmospheric isotope ratio (Ra = 1.384×10-6) are associated with known faults and volcanic provinces in Northern California. In the Central Valley, Rter varies from radiogenic to 2.25 Ra, complicating 3H/3He dating. The Rter was mapped by kriging, showing a correlation length of less than 50 km. The local predicted Rter was used to separate tritiogenic from atmospheric and terrigenic 3He. Regional groundwater recharge areas, indicated by young groundwater ages, are located in the southern Santa Clara Basin and in the upper LA basin and in the eastern San Joaquin Valley and along unlined canals carrying Colorado River water. Recharge in California is dominated by agricultural return flows, river recharge and managed aquifer recharge rather than precipitation excess. Combined application of noble gases and other groundwater tracers reveal the impact of engineered groundwater recharge and prove invaluable for the study of complex groundwater systems. This work was performed under the

  18. Distorted spin dependent spectral function of {sup 3}He and semi-inclusive deep inelastic scattering processes

    Energy Technology Data Exchange (ETDEWEB)

    Kaptari, Leonya P. [University of Perugia (Italy); INFN-Perugia (Italy); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Joint Inst. for Nuclear Research, Dubna (Russia); Del Dotto, Alessio [University of Rome, Rome (Italy); INFN-Roma (Italy); Pace, Emanuele [University of Rome (Italy); INFN-Tor Vergata (Italy); Salme, Giovanni [INFN-Roma (Italy); Scopetta, Sergio [University of Perugia (Italy); INFN-Perugia (Italy)

    2014-03-01

    The spin dependent spectral function, relevant to describe polarized electron scattering off polarized {sup 3}He, is studied, within the Plane Wave Impulse Approximation and taking into account final state interaction effects (FSI). In particular, the case of semi-inclusive deep inelastic scattering (SiDIS) is considered, evaluating the FSI of the hadronizing quark with the nuclear remnants. It is shown that particular kinematical regions can be selected to minimize the latter effects, so that parton distributions in the neutron can be accessed. On the other side, in the regions where FSI dominates, the considered reactions can elucidate the mechanism of hadronization of quarks during the propagation in the nuclear medium. It is shown that the obtained spin dependent spectral function can be directly applied to investigate the SiDIS reaction e-vector + {sup 3}He-vector to h+X, where the hadron h originates from the current fragmentation. Experiments of this type are being performed at JLab to extract neutron transverse momentum dependent parton distributions. As a case study, a different SiDIS process, with detection of slow (A-1) systems in the final state, is considered in more details, in order to establish when nuclear structure effects and FSI can be distinguished from elementary reactions on quasi-free nucleons. It is argued that, by a proper choice of kinematics, the origin of nuclear effects in polarized DIS phenomena and the details of the interaction between the hadronizing quark and the nuclear medium can be investigated at a level which is not reachable in inclusive deep inelastic scattering.

  19. Dispersion-Induced Splitting of the Collective Mode Spectrum in Axial and Planar Phases of Superfluid 3He

    Science.gov (United States)

    Brusov, Peter; Brusov, Pavel

    2009-05-01

    The whole collective mode spectrum in axial and planar phases of superfluid 3He with dispersion corrections is calculated for the first time. In axial A-phase the degeneracy of clapping modes depends on the direction of the collective mode momentum k with respect to the vector l (mutual orbital moment of Cooper pairs), namely: the mode degeneracy remains the same as in case of zero momentum k for k‖ l only. For any other directions there is a threefold splitting of these modes, which reaches maximum for k ⊥ l. In planar 2 D-phase, which exists in the magnetic field (at H> H C ) we find that for clapping modes the degeneracy depends on the direction of the collective mode momentum k with respect to the external magnetic field H, namely: the mode degeneracy remains the same as in case of zero momentum k for k‖ H only. For any other directions different from this one (for example, for k ⊥ H) there is twofold splitting of these modes. The obtained results imply that new interesting features can be observed in ultrasound experiments in axial and planar phases: the change of the number of peaks in ultrasound absorption into clapping mode. One peak, observed for these modes by Ling et al. (J. Low Temp. Phys. 78:187, 1990), will split into two peaks in a planar phase and into three peaks in an axial phase under the change of ultrasound direction with respect to the external magnetic field H in a planar phase and with respect to the vector l in an axial phase. In planar phase, some Goldstone modes in the magnetic field become massive (quasi-Goldstone) and have a similar twofold splitting under the change of ultrasound direction with respect to the external magnetic field H. The obtained results as well will be useful under interpretation of the ultrasound experiments in axial and planar phases of superfluid 3He.

  20. A systematics of optical model compound nucleus formation cross sections for neutrons, proton, deuteron, {sup 3}He and alpha particle incidents

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Toru [AITEL Corporation, Tokyo (Japan)

    2000-03-01

    Simple formulae to reproduce the optical model compound nucleus formation cross sections for neutron, proton, deuteron, triton, {sup 3}He and alpha particles are presented for target nuclei of light to medium weight mass region. (author)