WorldWideScience

Sample records for 2h 3he 6li

  1. An Updated 6Li(p, α)3He Reaction Rate at Astrophysical Energies with the Trojan Horse Method

    Science.gov (United States)

    Lamia, L.; Spitaleri, C.; Pizzone, R. G.; Tognelli, E.; Tumino, A.; Degl'Innocenti, S.; Prada Moroni, P. G.; La Cognata, M.; Pappalardo, L.; Sergi, M. L.

    2013-05-01

    The lithium problem influencing primordial and stellar nucleosynthesis is one of the most interesting unsolved issues in astrophysics. 6Li is the most fragile of lithium's stable isotopes and is largely destroyed in most stars during the pre-main-sequence (PMS) phase. For these stars, the convective envelope easily reaches, at least at its bottom, the relatively low 6Li ignition temperature. Thus, gaining an understanding of 6Li depletion also gives hints about the extent of convective regions. For this reason, charged-particle-induced reactions in lithium have been the subject of several studies. Low-energy extrapolations of these studies provide information about both the zero-energy astrophysical S(E) factor and the electron screening potential, Ue . Thanks to recent direct measurements, new estimates of the 6Li(p, α)3He bare-nucleus S(E) factor and the corresponding Ue value have been obtained by applying the Trojan Horse method to the 2H(6Li, α 3He)n reaction in quasi-free kinematics. The calculated reaction rate covers the temperature window 0.01 to 2T 9 and its impact on the surface lithium depletion in PMS models with different masses and metallicities has been evaluated in detail by adopting an updated version of the FRANEC evolutionary code.

  2. Comparison of Thermal Neutron Detection Efficiency of $^{6}$Li Scintillation Glass and $^{3}$He Gas Proportional Tube

    OpenAIRE

    Xu, Ming; Tang, Zhi-Cheng; Chen, Guo-Ming; Tao, Jun-Quan

    2013-01-01

    We report on a comparison study of the $^{3}$He gas proportional tube and the $^{6}$Li incorporated scintillation glasses on thermal neutron detection efficiency. Both $^{3}$He and $^{6}$Li are used commonly for thermal neutron detection because of their high neutron capture absorption coefficient. By using a neutron source $^{252}$Cf and a paraffin moderator in an alignment system, we can get a small beam of thermal neutrons. A flash ADC is used to measure the thermal neutron spectrum of eac...

  3. Energy dependence of the 6Li(π+,3He)3He reaction at 60, 75 and 90 MeV

    International Nuclear Information System (INIS)

    Differential cross sections for the pionic fission reaction 6Li(π+,3He)3He at T sub(π) = 60, 75 and 90 MeV have been measured for theta sub(c.m.) = 4l degrees. The energy dependence of the differential cross section is found to follow an exponential decrease with increasing incident pion energy and is compared with existing theoretical predictions

  4. AN UPDATED {sup 6}Li(p, {alpha}){sup 3}He REACTION RATE AT ASTROPHYSICAL ENERGIES WITH THE TROJAN HORSE METHOD

    Energy Technology Data Exchange (ETDEWEB)

    Lamia, L.; Spitaleri, C.; Sergi, M. L. [Dipartimento di Fisica e Astronomia, Universita di Catania, I-95123 Catania (Italy); Pizzone, R. G.; Tumino, A.; La Cognata, M. [INFN-Laboratori Nazionali del Sud, I-95125 Catania (Italy); Tognelli, E.; Degl' Innocenti, S.; Prada Moroni, P. G. [Dipartimento di Fisica, Universita di Pisa, I-56127 Pisa (Italy); Pappalardo, L. [Dipartimento di Fisica e Scienze della Terra, Universita di Ferrara, I-44100 Ferrara (Italy)

    2013-05-01

    The lithium problem influencing primordial and stellar nucleosynthesis is one of the most interesting unsolved issues in astrophysics. {sup 6}Li is the most fragile of lithium's stable isotopes and is largely destroyed in most stars during the pre-main-sequence (PMS) phase. For these stars, the convective envelope easily reaches, at least at its bottom, the relatively low {sup 6}Li ignition temperature. Thus, gaining an understanding of {sup 6}Li depletion also gives hints about the extent of convective regions. For this reason, charged-particle-induced reactions in lithium have been the subject of several studies. Low-energy extrapolations of these studies provide information about both the zero-energy astrophysical S(E) factor and the electron screening potential, U{sub e} . Thanks to recent direct measurements, new estimates of the {sup 6}Li(p, {alpha}){sup 3}He bare-nucleus S(E) factor and the corresponding U{sub e} value have been obtained by applying the Trojan Horse method to the {sup 2}H({sup 6}Li, {alpha} {sup 3}He)n reaction in quasi-free kinematics. The calculated reaction rate covers the temperature window 0.01 to 2T{sub 9} and its impact on the surface lithium depletion in PMS models with different masses and metallicities has been evaluated in detail by adopting an updated version of the FRANEC evolutionary code.

  5. Comparison of Thermal Neutron Detection Efficiency of $^{6}$Li Scintillation Glass and $^{3}$He Gas Proportional Tube

    CERN Document Server

    Xu, Ming; Chen, Guo-Ming; Tao, Jun-Quan

    2013-01-01

    We report on a comparison study of the $^{3}$He gas proportional tube and the $^{6}$Li incorporated scintillation glasses on thermal neutron detection efficiency. Both $^{3}$He and $^{6}$Li are used commonly for thermal neutron detection because of their high neutron capture absorption coefficient. By using a neutron source $^{252}$Cf and a paraffin moderator in an alignment system, we can get a small beam of thermal neutrons. A flash ADC is used to measure the thermal neutron spectrum of each detector, and the detected number of events is determined from the spectrum, then we can calculate the detection efficiency of different detectors. Meanwhile, the experiment have been modeled with GEANT4 to validate the results against the Monte Carlo simulation.

  6. Comparison of thermal neutron detection efficiency of 6Li scintillation glass and 3He gas proportional tube

    International Nuclear Information System (INIS)

    We report on a comparison study of the 3He gas proportional tube and the 6Li incorporated scintillation glasses on thermal neutron detection efficiency. Both 3He and 6Li are used commonly for thermal neutron detection because of their high neutron capture absorption coefficient. By using a neutron source 252Cf and a paraffin moderator in an alignment system, we can get a small beam of thermal neutrons. A flash ADC is used to measure the thermal neutron spectrum of each detector, and the detected number of events is determined from the spectrum, then we can calculate the detection efficiency of different detectors. Meanwhile, the experiment has been modeled with GEANT4 to validate the results against the Monte Carlo simulation. (authors)

  7. Study of the reactions 6Li(pα)3He, 6Li(dα)4He, 6Li(dp0)7Li and 6Li(dp1)7Li* from 300 keV to 1000 keV

    International Nuclear Information System (INIS)

    Experimental results are presented for the four reactions 6Li (pα)3He, 6Li (dα)4He, 6Li (dp0)7Li and 6Li (dp1)7Li* between 300 keV and 1000 keV. The angular distributions, the excitation curves and the total cross-section curves are presented in absolute values. (authors)

  8. The Trojan-Horse Method applied to the {sup 6}Li(p,{alpha}){sup 3}He reaction down to astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spitaleri, C.; Pappalardo, L.; Cherubini, S.; Del Zoppo, A.; La Cognata, M.; Musumarra, A.; Pellegriti, M.G.; Pizzone, R.G.; Rinollo, A.; Romano, S.; Typel, S

    2004-04-05

    The Trojan-Horse Method has been applied to the three-body d({sup 6}Li,{alpha}{sup 3}He)n break-up reaction in order to extract the bare nucleus S(E) factor for the {sup 6}Li(p,{alpha}){sup 3}He down to astrophysical energies.

  9. 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.

  10. Study of the {sup 6}Li + p → {sup 3}He + {sup 4}He reaction in inverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Betsou, C.; Pakou, A.; Aslanoglou, X.; Nicolis, N.G.; Sgouros, O.; Soukeras, V. [The University of Ioannina, Department of Physics and HINP, Ioannina (Greece); Cappuzzello, F. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); Acosta, L. [Universidad Nacional Autonoma de Mexico, Instituto de Fisica, Mexico Distrito Federal (Mexico); INFN, Catania (Italy); Agodi, C.; Carbone, D.; Cavallaro, M.; Di Pietro, A.; Fernandez-Garcia, J.P.; Figuera, P.; Fisichella, M. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Foti, A. [Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); INFN, Catania (Italy); Keeley, N. [National Centre for Nuclear Research, Otwock (Poland); Marquinez-Duran, G.; Martel, I. [Universidad de Huelva, Departamento de Fisica Aplicada, Huelva (Spain); Mazzocco, M.; Strano, E.; Torresi, D. [Universita di Padova, Departimento di Fisica e Astronomia, Padova (Italy); INFN, Padova (Italy); Pierroutsakou, D. [INFN, Napoli (Italy); Rusek, K. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Stiliaris, E. [University of Athens, Institute of Accelerating Systems and Applications and Department of Physics, Athens (Greece)

    2015-07-15

    Angular distribution measurements were performed for the {sup 6}Li + p → {sup 3}He + {sup 4}He reaction in inverse kinematics at incident energies of 2.7, 3.3, 4.2 and 4.8 MeV/u. The detection of both recoils ({sup 3}He and {sup 4}He) over the laboratory angle range θ{sub lab} = 16 {sup circle} to 34 {sup circle} allowed the determination of the angular distribution over a wide angular range in the center-of-mass frame (θ{sub c.m.} ∝ 40 {sup circle} to 140 {sup circle}). The results clarify inconsistencies between existing data sets and are consistent with compound nucleus model calculations. (orig.)

  11. A microscopic three-cluster model with nuclear polarization applied to the resonances of 7Be and the reaction 6Li(p,3He)4He

    CERN Document Server

    Vasilevsky, V S; Broeckhove, J; Kovalenko, T P

    2008-01-01

    A microscopic model for three-cluster configurations in light nuclei is presented. It uses an expansion in terms of Faddeev components for which the dynamic eqations are derived. The model is designed to investigate binary channel processes in a compound system. Gaussian and oscillator bases are used to expand the wave function and to represent appropriate boundary conditions. We study the effect of cluster polarization on ground and resonance states of 7Be, and on the astrophysical S-factor of the reaction 6Li(p,3He)4He.

  12. 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

  13. 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.

  14. Inclusive $^{2}H(^{3}He,t)$ reaction at 2 GeV

    CERN Document Server

    Ramstein, B; Bachelier, D; Berquist, I; Boivin, M; Boyard, J L; Brockstedt, A; Carlén, L; Dahl, R; Ekström, R E; Ellegaard, C; Gaarde, C; Hennino, T; Jourdain, J C; Goodman, C; Larsen, J S; Radvanyi, P; Roy-Stephan, M

    1999-01-01

    The inclusive 2H(3He,t) reaction has been studied at 2 GeV for energy transfers up to 500 MeV and scattering angles from 0.25 up to 4 degrees. Data are well reproduced by a model based on a coupled-channel approach for describing the NN and N Delta systems. The effect of final state interaction is important in the low energy part of the spectra. In the delta region, the cross-section is very sensitive to the effects of Delta-N interaction and Delta N - NN process. The latter has also a large influence well below the pion threshold. The calculation underestimates the experimental cross-section between the quasi-elastic and the delta peaks; this is possibly due to projectile excitation or purely mesonic exchange currents.

  15. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Anders, M.; Bemmerer, D.; Elekes, Z.; Marta, M. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Trezzi, D.; Mazzocchi, C. [INFN, Sezione di Milano, Milano (Italy); Bellini, A.; Costantini, H.; Corvisiero, P.; Lemut, A.; Prati, P. [Universita di Genova (Italy); INFN, Sezione di Genova, Dipartimento di Fisica, Genova (Italy); Aliotta, M.; Davinson, T.; Scott, D. [University of Edinburgh, SUPA, School of Physics and Astronomy, Edinburgh (United Kingdom); Broggini, C.; Caciolli, A.; Erhard, M.; Menegazzo, R.; Rossi Alvarez, C. [INFN, Sezione di Padova, Padova (Italy); Formicola, A.; Junker, M. [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy); Fueloep, Zs.; Gyuerky, G.; Somorjai, E.; Szuecs, T. [Institute of Nuclear Research (ATOMKI), Debrecen (Hungary); Gervino, G. [Universita di Torino (Italy); INFN, Dipartimento di Fisica Sperimentale, Torino (Italy); Guglielmetti, A. [INFN, Sezione di Milano, Milano (Italy); Universita degli Studi di Milano, Milano (Italy); Gustavino, C. [INFN, Sezione di Roma ' ' La Sapienza' ' , Roma (Italy); Straniero, O. [INFN, Sezione di Napoli, Napoli (Italy); Osservatorio Astronomico di Collurania, Teramo (Italy); Collaboration: LUNA Collaboration

    2013-02-15

    The production of the stable isotope {sup 6}Li in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological {sup 6}Li plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of {sup 7}Li abundances and would point to a predominantly primordial origin of {sup 6}Li, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang {sup 6}Li production must be revisited. The main production channel for {sup 6}Li in the Big Bang is the {sup 2}H({alpha},{gamma}){sup 6}Li 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 {sup 2}H(d,n){sup 3}He reaction. Due to the ultra-low laboratory neutron background at LUNA, the effect of this weak flux of 2-3 MeV neutrons on well-shielded high-purity germanium detectors has been studied in detail. Data have been taken at 280 and 400keV {alpha}-beam energy and for comparison also using an americium-beryllium neutron source. (orig.)

  17. 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. PMID:25105610

  18. 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.

  19. New determination of the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reaction rates at astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spartà, R.; Spitaleri, C.; Pizzone, R. G.; La Cognata, M.; Rapisarda, G. G.; Romano, S.; Sergi, M. L. [Laboratori Nazionali del Sud-INFN, Catania (Italy); Mukhamedzhanov, A. M. [Cyclotron Institute Texas A and M University-College Station, Texas (United States); Typel, S. [GSI Helmholtzzentrum für Schwerionenforschung GmbH-Theorie Darmstadt (Germany); Tognelli, E.; Degl' Innocenti, S.; Prada Moroni, P. G. [Dipartimento di Fisica, Università di Pisa, and INFN-Sezione di Pisa, Pisa (Italy); Burjan, V.; Kroha, V.; Hons, Z.; Mrazek, J.; Piskor, S. [Nuclear Physics Institute of ASCR-Rez near Prague (Czech Republic); Lamia, L., E-mail: tumino@lns.infn.it [Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, Catania (Italy)

    2014-04-20

    The cross sections of the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions have been measured via the Trojan Horse method applied to the quasi-free {sup 2}H({sup 3}He,p {sup 3}H){sup 1}H and {sup 2}H({sup 3}He,n {sup 3}He){sup 1}H processes at 18 MeV off the proton in {sup 3}He. For the first time, the bare nucleus S(E) factors have been determined from 1.5 MeV, across the relevant region for standard Big Bang nucleosynthesis, down to the thermal energies of deuterium burning in the pre-main-sequence (PMS) phase of stellar evolution, as well as of future fusion reactors. Both the energy dependence and the absolute value of the S(E) factors deviate by more than 15% from the available direct data and existing fitting curves, with substantial variations in the electron screening by more than 50%. As a consequence, the reaction rates for astrophysics experience relevant changes, with a maximum increase of up to 20% at the temperatures of the PMS phase. From a recent primordial abundance sensitivity study, it turns out that the {sup 2}H(d,n){sup 3}He reaction is quite influential on {sup 7}Li, and the present change in the reaction rate leads to a decrease in its abundance by up to 10%. The present reaction rates have also been included in an updated version of the FRANEC evolutionary code to analyze their influence on the central deuterium abundance in PMS stars with different masses. The largest variation of about 10%-15% pertains to young stars (≤1 Myr) with masses ≥1 M {sub ☉}.

  20. 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...

  1. {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions at sub-coulomb energies

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spitaleri, C.; Mukhamedzhanov, A. M.; Typel, S.; Sparta, R.; Aliotta, M.; Kroha, V.; Hons, Z.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Mrazek, J.; Pizzone, R. G.; Rapisarda, G. G.; Romano, S.; Sergi, M. L. [Universita degli Studi di Enna Kore, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Cyclotron Institute Texas A and M University - College Station, Texas (United States); Excellence Cluster Universe - Technische Universitaet Muenchen, Garching, Germany and GSI Helmholtzzentrum fuer Schwerionenforschung GmbH - Theorie Darmstadt (Germany); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); School of Physics and Astronomy - University of Edinburgh, SUPA (United Kingdom); Nuclear Physics Institute of ASCR - Rez near Prague (Czech Republic); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Nuclear Physics Institute of ASCR - Rez near Prague (Czech Republic); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy)

    2012-11-20

    The {sup 2}H({sup 3}He,p{sup 3}H){sup 1}H and {sup 2}H({sup 3}He,n{sup 3}He){sup 1}H processes have been measured in quasi free kinematics to investigate for the first time the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions by means of the Trojan Horse Method. The {sup 3}He+d experiment was performed at 18 MeV, corresponding the a d-d energy range from 1.5 MeV down to 2 keV. This range overlaps with the relevant region for Standard Big Bang Nucleosynthesis as well as with the thermal energies of future fusion reactors and deuterium burning in the Pre Main Sequence phase of stellar evolution. This is the first pioneering experiment in quasi free regime where the charged spectator is detected. Both the energy dependence and the absolute value of the bare nucleus S(E) factors have been extracted for the first time. They deviate by more than 15% from available direct data with new S(0) values of 57.4{+-}1.8 MeVb for {sup 3}H+p and 60.1{+-}1.9 MeVb for {sup 3}He+n. None of the existing fitting curves is able to provide the correct slope of the new data in the full range, thus calling for a revision of the theoretical description. This has consequences in the calculation of the reaction rates with more than a 25% increase at the temperatures of future fusion reactors.

  2. Impact of alternate fusion fuels on fusion reactor technology: an initial assessment study. [Catalyzed D, D-/sup 3/He, p-/sup 6/Li, p-/sup 7/Li, D-/sup 6/Li, p-/sup 11/B, /sup 3/He-/sup 3/He

    Energy Technology Data Exchange (ETDEWEB)

    Baker, C.C.; Bolon, A.; Clemmer, R.

    1979-11-01

    The initial results of a study carried out to assess some of the technology implications of non-D-T fusion fuel cycles are presented. The primary emphasis in this report is on D-D, catalyzed-D and D-/sup 3/He fuel cycles. Tokamaks and field-reversed mirrors have been selected as sample confinement concepts. A new technique of employing neutronic computer codes to study the transport of cyclotron radiation for cases of non-uniform density and temperature profiles is described. The technology areas considered include first wall design considerations, shielding requirements, fuel cycle requirements and some safety and environmental considerations. Conclusions resulting from the study are also presented.

  3. 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.

  4. S-factor measurement of the 2H(α,γ)6Li reaction at energies relevant for Big-Bang nucleosynthesis

    International Nuclear Information System (INIS)

    For about 20 years now, observations of 6Li in several old metal-poor stars inside the halo of our galaxy have been reported, which are largely independent of the stars' metallicity, and which point to a possible primordial origin. The observations exceed the predictions of the Standard Big-Bang Nucleosynthesis model by a factor of 500. In the relevant energy range, no directly measured S-factors were available yet for the main production reaction 2H(α,γ)6Li, while different theoretical estimations have an uncertainty of up to two orders of magnitude. The very small cross section in the picobarn range has been measured with a deuterium gas target at the LUNA accelerator (Laboratory for Underground Nuclear Astrophysics), located deep underground inside Laboratori Nazionali del Gran Sasso in Italy. A beam-induced, neutron-caused background in the γ-detector occurred which had to be analyzed carefully and subtracted in an appropriate way, to finally infer the weak signal of the reaction. For this purpose, a method to parameterize the Compton background has been developed. The results are a contribution to the discussion about the accuracy of the recent 6Li observations, and to the question if it is necessary to include new physics into the Standard Big-Bang Nucleosynthesis model.

  5. 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....

  6. A study of the inclusive inelastic scattering of 100 MeV pions from 2H, 3He and 4He

    International Nuclear Information System (INIS)

    Measurements were carried out of the double-differential cross sections of 100 MeV positive and negative pions inelastically scattered from 2H, 3He and 4He. Inclusive spectra and angular distributions of the scattered pions from the (π,π') reaction were obtained at several angles for the three targets using a magnetic spectrometer. The targets considered in the experiment were all gases. The yields of the scattered pions from 2H, 3He and 4He were normalized to measured 1H scattering data and to the known π+N cross sections in the literature. The angular distributions of 100 MeV pions scattered from 2H, 3He and 4He at the back angles (θ/sub lab/ ≥ 750) were found to have very nearly the same shape as the free π+-p distribution at this energy. The ratios of the energy- and angle-integrated π+ inelastic scattering cross sections at the back angles compared to the free π+-p cross sections were found to be 0.69 +- 0.03 for 2H, 1.42 +- 0.06 for 3He, and 0.88 +- 0.03 for 4He. The inelastic scattering reaction of pions from 2H, 3He and 4He were interpreted from the point of view that the initial interaction is that of a pion with a single nucleon. Classical and quantum mechanical calculations were carried out to better understand the πN interaction inside nuclei. It was found that pion interactions with 2H, 3He and 4He at energies below the (3,3) resonance can be viewed effectively in terms of pion interaction with individual nucleons in these nuclei. It was also found that pion absorption cross section in 4He is unusually large compared to that in other nuclei. Some possible reasons are suggested for this behavior of pions interacting with 4He. 80 refs., 42 figs., 29 tabs

  7. Towards the study of 2H(p, γ)3He reaction in the Big Bang Nucleosynthesis energy range in LUNA

    Science.gov (United States)

    Kochanek, Izabela

    2016-04-01

    The Big Bang Nucleosynthesis began a few minutes after the Big Bang, when the Universe was sufficiently cold to allow deuterium nuclei to survive photo-disintegration. The total amount of deuterium produced in the Universe during the first minutes depends on the cosmological parameters (like the energy density in baryons, Ω bh 2, and the effective neutrino number, Neff ) and on the nuclear cross sections of the relevant reactions. The main source of uncertainty in the deuterium estimation comes from the 2H(p, γ)3He cross section. Measurements of Cosmic Microwave Background (CMB) anisotropies obtained by the Planck satellite are in very good agreement with the theoretical predictions of the minimal ΛCDM cosmological model, significantly reducing the uncertainty on its parameters. The Planck data allows to indirectly deduce with very high precision the abundances of primodial nuclides, such as the primodial deuterium fraction 2H/H = (2.65 ± 0.07) .10-5 (68% C.L.). The astrophysical observations in damped Lyman-a systems at high redshifts provide a second high accuracy measurement of the primodial abundance of deuterium 2H/H = (2.53 ± 0.04) · 10-5 (68% C.L.). The present experimental status on the astrophysical S-factor of the 2H(p, γ)3He reaction in the BBN energy range, gives a systematic uncertainties of 9%. Also the difference between ab-initio calculations and experimental values of S12 is at the level of 10%. In order to clarify the actual scenario, a measurement of 2H(p, γ)3He cross section with a precision of a few percent in the 70-400 keV energy range is planned at LUNA in 2016. A feasibility test of the measurement has been performed in October 2014, giving the preliminary results on the cross section. The experimental setup for the test and final measurement campaign will be presented.

  8. Measurements and calculations of neutron leakage spectra from slabs irradiated with 9Be(d, n)10B 2H(d, n)3He and Pu-Be neutrons

    International Nuclear Information System (INIS)

    The spectra of neutrons from the 9Be(d, n)10B, 2H(d, n)3He and Pu-Be sources passing through slabs of water, graphite, Al, Fe and Pb up to 20 cm in thickness were measured by a pulse height response spectrometer in the 1.5-15 MeV range. The measured leakage spectra have been compared with calculated results obtained using the three dimensional Monte-Carlo code MCNP-4A and point-wise cross sections from the ENDF/B-IV, ENDF/B-VI and JENDL-3.1 data files. A comparison of the measured and calculated data has shown that the MCNP-4A code with an appropriate library can reasonably approximate the measured leakage spectra

  9. Measurements and calculations of neutron leakage spectra from slabs irradiated with {sup 9}Be(d, n){sup 10}B {sup 2}H(d, n){sup 3}He and Pu-Be neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Olah, L.; Jordanova, J.; El-Megrab, A.M.; Darsono, Perez N.; Yousif, M.Y.A.; Csikai, J. [Institute of Experimental Physics, Kossuth University, Debrecen (Hungary); Fenyvesi, A.; Majdeddin, A.D. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Debrecen (Hungary)

    1999-03-01

    The spectra of neutrons from the {sup 9}Be(d, n){sup 10}B, {sup 2}H(d, n){sup 3}He and Pu-Be sources passing through slabs of water, graphite, Al, Fe and Pb up to 20 cm in thickness were measured by a pulse height response spectrometer in the 1.5-15 MeV range. The measured leakage spectra have been compared with calculated results obtained using the three dimensional Monte-Carlo code MCNP-4A and point-wise cross sections from the ENDF/B-IV, ENDF/B-VI and JENDL-3.1 data files. A comparison of the measured and calculated data has shown that the MCNP-4A code with an appropriate library can reasonably approximate the measured leakage spectra.

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

    OpenAIRE

    Pizzone, R. G.; Spitaleri, C.(Dip. di Fisica e Astronomia, Univ. di Catania, via S. Sofia, Catania, Italy); Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L.; M. La Cognata; Lamia, L; Rinollo, A.; Spartá, R.; A. Tumino

    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 ag...

  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. Deformation Effects in 6Li

    International Nuclear Information System (INIS)

    The asymptotic D - to S -state ratio η for the 6Li> bound-state overlap is determined from measurements of the tensor analyzing powers for (6Li,d ) reactions on medium-heavy targets. The reactions are described by the distorted-wave Born approximation assuming a direct α -particle transfer reaction mechanism. The calculations provide good agreement with cross section and vector analyzing power data. A best fit to the tensor analyzing power data results in a new value of η=+0.0003±0.0009 , much smaller than previous experimental and theoretical determinations. copyright 1998 The American Physical Society

  14. ^3He Spin Pump

    Science.gov (United States)

    Yamaguchi, A.; Ishimoto, H.; Kojima, H.

    2009-03-01

    The superfluid component of ^3He A1 phase is spin-polarized. The process of forcing the superfluid component through a spin filtering structure, in a manner of mechano-magnetic effect, can be used to increase the spin polarization beyond the equilibrium under a given applied magnetic field. We have constructed a test cell in which a glass capillary array acts as the spin (and entropy) filter and an electrostatically actuated diaphragm forces the superfluid flow through it. Preliminary results show that a maximum relative increase of polarization by 50 % could be achieved. The maximum increase in polarization appears to be limited by the critical superfluid flow through the channels in the glass capillary array. The dependence of the observed effects on temperature, pressure and magnetic field will be presented.

  15. 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.

  16. Updated evidence of the Trojan horse particle invariance for the 2H(d,p)3H reaction

    Science.gov (United States)

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

    2013-02-01

    The Trojan horse nucleus invariance for the binary d(d,p)t reaction was tested by means of an experiment using the quasifree 2H(6Li,pt)4He and 2H(3He,pt)H reactions after 6Li and 3He breakup, respectively. The astrophysical S(E) factor for the d(d,p)t binary process was extracted from the present data in the framework of the plane wave approximation applied to the two different breakup 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 the binary indirect cross section on the chosen Trojan horse nucleus also for the present case.

  17. Photodisintegration of 3H and 3He

    International Nuclear Information System (INIS)

    The photoneutron cross sections for 3H and 3He have been measured from threshold to approx. 25 MeV with monoenergetic photons from the annihilation in flight of fast positrons at the LLL Electron-Positron Linear Accelerator facility. These reactions include the two-body breakup of 3H and the three-body breakup of both 3H and 3He; these measurements for 3H are the first to span the energy region across the peaks of the cross sections. An efficient BF3-tube-and-paraffin neutron detector and high-pressure gaseous samples of several moles each (the activity of the 3H sample was approx. 200,000 Ci) were employed in these measurements. Measurements on 16O and 2H also were performed to verify the absolute cross-section scale. The results, when compared with each other and with results for the two-body breakup cross section for 3He from the literature, show that the two-body breakup cross sections for 3H and 3He have nearly the same shape, but the one for 3He lies lower in magnitude; the three-body breakup cross section for 3He lies higher in magnitude and is broader in the peak region and also rises less sharply from threshold than that for 3H; and these measured differences between the cross sections for the breakup modes largely compensate in their sum, so that the total photon absorption cross sections for 3H and 3He are nearly the same in both size and shape at energies near and above their peaks. Theoretical results from the literature disagree with the experimental results to a certain extent over the entire photon-energy region for which the photoneutron cross sections were measured. 50 figures, 7 tables

  18. Trojan Horse particle invariance for 2H(d,p)3H reaction: a detailed study

    OpenAIRE

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

    2014-01-01

    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,p)t reaction was therefore tested using the quasi free 2H(6Li, pt)4He and 2H(3He,pt)H reaction...

  19. Observations of 6Li in Galactic Stars

    Science.gov (United States)

    Hobbs, L. M.

    2000-05-01

    Several important goals have motivated observationally challenging attempts to measure 6Li/7Li isotopic ratios and, hence, 6Li abundances in stars. In particular, a general understanding, based on cosmic-ray spallation reactions, of the nucleosynthetic origins of the very low Galactic abundances of 6Li, Be, and B has followed from measurements of both the relative and the absolute abundances of these various, related isotopes. In the cases of Be and B, such data are currently available for 20 or more stars that span a wide range of metallicity, i.e. age. In contrast, nuclear burning of the very fragile 6Li nuclei during stellar contraction to the main sequence generally reduces the surface abundance of this lighter isotope below the observable limit. A few relatively nearby stars of low metallicity which are found close to the Population II main-sequence turnoff during later hydrogen burning seem to constitute the observable exceptions. Spectra of very high quality, typically with R > 100,000 and S/N > 400 at V > 9.0, are needed to reveal the small extra asymmetry and the small extra width that are introduced into the profile of the isotopically blended Li I 6707 A line by the small fractions of 6Li detected so far. Precise measurements of (or, in all but a few cases, uppper limits on) the 6Li/7Li ratio are now available for almost 30 stars. At a ratio 6Li/7Li = 0.06, the first positive detection of stellar 6Li was achieved in 1993 for the turnoff halo star HD 84937, by Smith, Lambert, & Nissen. Probable detections of the lighter isotope at generally similar isotopic ratios have since been reported for four additional metal-poor stars. The imminent availability of more telescopes in the 8m to 10m class promises a rewarding extension of this effort to a relatively large number of excellent, fainter 6Li candidates.

  20. 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%.

  1. Mechanisms of emission of particles charged in 6Li + 6Li and 6Li + 10B reactions at low energies

    International Nuclear Information System (INIS)

    The lithium 6 nucleus is a projectile of interest to study nuclear reactions at low energy due to the possibility to obtain high heats of reaction, and to its structure which can play an important role in the projectile-target interaction. This research thesis focused on the study of two low-energy reactions provoked by lithium projectiles. These reactions are studied within the framework of the theoretical model of aggregates. The first part presents the experimental conditions of both reactions, reports the development and analysis of nuclear plates, and the transformation of a given type of particle histogram into a spectrum in the mass centre system. The next parts report the study of the 6Li + 6Li reaction (previous results, kinematic analysis, spectrum of secondary particles, theoretical analysis of results) and of the 6Li + 10B reaction (previous results, experimental results, study of the continuous spectrum of alpha particle, reaction mechanisms)

  2. 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...

  3. A multipurpose 3He refrigerator

    Science.gov (United States)

    Pizzo, L.; Dall'Oglio, G.; Martinis, L.; Sabbatini, L.

    2006-10-01

    We introduce a mini 3He refrigerator, operating at ˜300 mK starting from 4.2 K without pumping on the main 4He bath. The innovative idea is that the present one is suitable for a very fast operation; for its use, it is sufficient a storage 4He Dewar. In this way we drastically reduce the time required to cool it down, because there is no need for a classic cryostat. This prototype is particularly aimed for all those operations in which it is necessary to test a large number of samples that do not require long duration measurements at low temperature.

  4. 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.

  5. 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.

  6. 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. PMID:27472118

  7. 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.

  8. 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.

  9. Feshbach resonances in fermionic 6Li

    International Nuclear Information System (INIS)

    Feshbach resonances in 6Li were experimentally studied and theoretically analyzed. In addition to two previously known s-wave resonances, three p-wave resonances were found. Four of these resonances are narrow and yield a precise value of the singlet scattering length. The position of the broad s-wave resonance near 83 mT is mostly sensitive to the triplet potential. It was previously determined in a molecule-dissociation experiment for which we, here, discuss systematic shifts

  10. 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.

  11. Trojan Horse particle invariance for 2H(d,p)3H reaction: a detailed study

    Science.gov (United States)

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

    2014-03-01

    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,p)t reaction was therefore tested using the quasi free 2H(6Li, pt)4He and 2H(3He,pt)H reactions after 6Li and 3He 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.

  12. The Panofsky ratio in 3He

    International Nuclear Information System (INIS)

    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. (orig.)

  13. 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.

  14. 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.

  15. Enhancement of the CP-odd effect in the nuclear electric dipole moment of $^6$Li

    CERN Document Server

    Yamanaka, Nodoka

    2015-01-01

    We calculate for the first time the electric dipole moment (EDM) of the $^6$Li nucleus within the alpha + p + n three-body cluster model using the Gaussian expansion method, assuming the one meson exchange P, CP-odd nuclear forces. It is found that the EDM of the $^6$Li is 2 times more sensitive on the isovector pion exchange P, CP-odd nuclear force than the deuteron EDM, due to the CP-odd interaction between the nucleons and the alpha cluster. The $^9$Be EDM is also calculated in the same framework as an alpha + alpha + n three-body system. We also test the ab initio calculation of the EDM of the deuteron, $^3$H and $^3$He nuclei using the realistic Argonne $v18$ nuclear force. In the ab initio calculations, good agreements with previous studies are obtained. We finally discuss the prospects for the new physics beyond the standard model.

  16. 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.

  17. 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.).

  18. Primordial α +d →6Li+γ reaction and second lithium puzzle

    Science.gov (United States)

    Mukhamedzhanov, A. M.; Shubhchintak, Bertulani, C. A.

    2016-04-01

    During the Big Bang, 6Li was synthesized via the 2H(α ,γ ) 6Li reaction. After almost 25 years of the failed attempts to measure the 2H(α ,γ ) 6Li reaction in the laboratory at Big Bang energies, just recently the LUNA Collaboration presented the first successful measurements at two different Big Bang energies [Anders et al., Phys. Rev. Lett. 113, 042501 (2014), 10.1103/PhysRevLett.113.042501]. In this paper we will discuss how to improve the accuracy of the direct experiment. To this end the photon's angular distribution is calculated in the potential model. It contains contributions from electric dipole and quadrupole transitions and their interference, which dramatically changes the photon's angular distribution. The calculated distributions at different Big Bang energies have a single peak at ˜50∘ . These calculations provide the best kinematic conditions to measure the 2H(α ,γ ) 6Li reaction. The expressions for the total cross section and astrophysical factor are also derived by integrating the differential cross section over the photon's solid angle. The LUNA data are in excellent agreement with our calculations using a potential approach combined with a well established asymptotic normalization coefficient for 6Li→α +d . Comparisons of the available experimental data for the S24 astrophysical factor and different calculations are presented. The Big Bang lithium isotopic ratio 6Li/7Li=(1.5 ±0.3 ) ×10-5 following from the LUNA data and the present analysis are discussed in the context of the disagreement between the observational data and the standard Big Bang model, which constitutes the second lithium problem.

  19. Measurement of polarization of 3He with mobile polarized 3He neutron spin filter

    Science.gov (United States)

    Ino, T.; Kim, G. N.; Lee, M. W.; Lee, S. M.; Kim, J. Y.; Lee, S. W.; Skoy, V. R.

    2014-03-01

    A mobile polarized 3He neutron spin filter was developed for both optical pumping and transportation, and the polarization of 3He was measured with cold neutrons of HANARO in KAERI. The progress of polarization build-up during the optical pumping of the 3He cell was observed by adiabatic fast-passage NMR system. The 3He cell was made of an alumino-silicate glass GE-180 with a cylindrical shape of 40 mm in diameter and 60 mm in length from KEK. A cell contained 5.74 barṡcm of 3He gas. The whole installation after 8 h pumping was transported to the general-purpose test station of the HANARO research reactor and the polarization of 3He was measured with cold neutrons. The measured polarization of 3He was 0.18 ± 0.01 by measuring the neutron transmission through the 3He cell.

  20. 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.

  1. 3He melting pressure temperature scale

    DEFF Research Database (Denmark)

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

    1976-01-01

    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......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...

  2. 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.

  3. Neutron detector based on Particles of 6Li glass scintillator dispersed in organic lightguide matrix

    International Nuclear Information System (INIS)

    Most 3He replacement neutron detector technologies today have overlapping neutron–gamma pulse-height distributions, which limits their usefulness and performance. Different techniques are used to mitigate this shortcoming, including Pulse Shape Discrimination (PSD) or threshold settings that suppress all gammas as well as much of the neutrons. As a result, count rates are limited and dead times are high when PSD is used, and the detection efficiency for neutron events is reduced due to the high threshold. This is a problem in most applications where the neutron–gamma separation of 3He detectors had been essential. This challenge is especially severe for neutron coincidence and multiplicity measurements that have numerous conflicting requirements such as high detection efficiency, short die-away time, short dead time, and high stability. 6Li-glass scintillators have excellent light output and a single peak distribution, but they are difficult to implement because of their gamma sensitivity. The idea of reducing the gamma sensitivity of 6Li-glass scintillators by embedding small glass particles in an organic light-guide medium was first presented by L.M. Bollinger in the early 60s but, to the best of our knowledge, has never been reduced to practice. We present a proof of principle detector design and experimental data that develop this concept to a large-area neutron detector. This is achieved by using a multi-component optical medium (6Li glass particles attached to a glass supporting structure and a mineral oil light guide) which matches the indices of refraction and minimizes the absorption of the 395 nm scintillator light. The detector design comprises a 10 in. long tube with dual end readout with about 3% volume density of 6Li glass particles installed. The presented experimental data with various neutron and gamma sources show the desired wide gap between the neutron and gamma pulse height distributions, resulting in a true plateau in the counting

  4. 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.

  5. 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.

  6. Quantum prewetting transitions in liquid 3He

    International Nuclear Information System (INIS)

    Multilayer 3He film growth on weak-binding alkali substrates is investigated with a non-local density functional theory. Although 3He wets all substrates, prewetting transitions are predicted to occur on cesium and potassium. Emphasis is put on the role played by the Fermi statistics. Prewetting critical temperatures are estimated. Continuous wetting at zero temperature is recovered with increasing strength of substrate potential. The heat capacity and the magnetization of the films exhibits steps associated with the occupation of two-dimensional (2D) Fermi discs. (authors). 24 refs., 4 figs

  7. Studies of the D state of 6Li using the FSU polarized 6Li Beam

    International Nuclear Information System (INIS)

    One way to quantify the D-state component of the wave function of a nucleus is by the quantity η, the ratio of the D- and S-state asymptotic normalization constants. Analyses of the analyzing powers from transfer reactions induced by polarized ions have been useful for the determination of η in the A=2-4 systems. In an effort to determine η for the d+α relative motion in 6Li we have measured analyzing powers for (6L rvec i,d) reactions on 58Ni and 40Ca at E(6Li)=34 and h;MeV. The experiments were performed at Florida State University using the Optically Pumped Polarized Lithium Ion Source. We compared the data with the results of well-constrained DWBA calculations assuming a direct α-particle transfer mechanism. With η the only free parameter in the calculations, a best fit to the tensor analyzing power data results in an average value of η=+0.0003±0.0009, much smaller than previous determinations. copyright 1999 American Institute of Physics

  8. 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.

  9. Study of the {sup 3} He(d, p){sup 4} He reaction through the Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    La Cognata, M. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Chimiche e Fisiche per l' Ingegneria, Universita di Catania (Italy); Musumarra, A. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Chimiche e Fisiche per l' Ingegneria, Universita di Catania (Italy); Spitaleri, C. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Chimiche e Fisiche per l' Ingegneria, Universita di Catania (Italy)] (and others)

    2005-07-25

    The astrophysically relevant {sup 3} He(d, p){sup 4} He reaction was indirectly studied by means of the Trojan Horse Method applied to the {sup 6} Li({sup 3} He, p{alpha}){sup 4} He three body process performed at 5 and 6 MeV. The bare astrophysical S(E)-factor extracted in Modified Plane Wave Born Approximation was compared with the free behaviour and an independent estimate of the screening potential was obtained, confirming the discrepancy with the adiabatic limit.

  10. Pion absorption in flight on 3He

    International Nuclear Information System (INIS)

    Pion absorption in flight on 3He has been measured in a kinematically complete manner. The experiment was done in the πE1-channel at the Swiss Institute for Nuclear Research, SIN, using π+- and π--beams of 120 and 165 MeV kinetic energy. Two of the emitted particles were measured in coincidence and identified by their time-of-flight/pulseheight relation. The obtained two-dimensional energy representation enabled a separation of the different kinematical regions and exhibited a clear enhancement in the region of quasifree absorption, QFA. (orig./WL)

  11. Duoplasmatron source modifications for 3He+ operation

    International Nuclear Information System (INIS)

    A duoplasmatron ion source is used to produce 25 mA of 3He+ with a pulse width of ∼80ms at 360 Hz for acceleration to 10.5 MeV. At this energy, 3He striking water or carbon targets can produce short lived isotopes of 11C, 13N, 15O, and 18F for medical positron emission tomography (PET). A duoplasmatron ion source was chosen originally since it is capable of a sufficient singly charged helium beam with an acceptable gas consumption. Stable long-term operation of the source required a change in the filament material to molybdenum, and a careful understanding of the oxide filament conditioning, operation and geometry. Other improvements, particularly in the electronics, were helpful to increasing the reliability. The source has operated for many months at ∼2.5% duty factor without significant problems and with good stability. We report here the effort that was done to make this source understandable and reliable

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

    International Nuclear Information System (INIS)

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

  13. Formation of 3He droplets in dilute 3He-4He solid solutions

    Science.gov (United States)

    Huan, Chao; Candela, Don; Kim, Sung; Yin, Liang; Xia, Jiang-Sheng; Sullivan, Neil

    2015-03-01

    We review the different stages of the formation of 3He droplets in dilute solid 3He-4He solutions. The studies are interesting because the phase separation in isotopic helium mixtures is a first-order transition with a conserved order parameter. The rate of growth of the droplets as observed in NMR studies is compared with the rates expected for homogeneous nucleation followed by a period of coarsening known as Ostwald ripening. Work suported by the National Science Foundation - DMR-1303599 and DMR- 1157490 (National High Magnetic Field Laboratory).

  14. Sequential mechanism for the Li7 (He3, α)6 Li(d)α reaction at incident energy between 2.5 and 11.5 MeV

    International Nuclear Information System (INIS)

    A strictly sequential mechanism appears to appropriate for the Li7 (3He,α)6Li(d)α reaction in the energy range between 2.5 and 11.5 MeV. It can be described by a first direct emission mechanism and a second delayed emission

  15. Critical opalescent light scattering from 3He

    International Nuclear Information System (INIS)

    The experimental work reported in this paper was stimulated by the widespread revival of interest in critical phenomena. In this experiment the authors measured the intensity of light scattered from 3He while very slowly warming the sample at constant pressure through the critical region. About 0.3 mW from a helium-neon laser was incident on the cell; cell temperature was recorded continuously, as was the light scattered at 45 degrees and 135 degrees. A succession of passes was made at different pressures, all less than c, so these results apply only in the one-phase region above the critical point. Sample density at the beginning of a pass began at ρ > c, then decreased as the sample warmed to ρ c. The scattering intensity increased monotonically as the molar density decreased toward the critical density, then decreased monotonically thereafter on that isobaric pass. The scattering maximum on each pass occurred at the temperature max where the isothermal compressibility was a maximum. The asymptotic divergence of T was evaluated along the locus of these maxima

  16. {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.

  17. Possibility of optically pumped 3He as an internal target

    International Nuclear Information System (INIS)

    A number of techniques can be listed for obtaining polarized 3He nuclei. This paper focuses only on direct optical pumping of 3He(3S1) with collisional transfer to 3He. A comprehensive review is not attempted. The basic aspects of the method are presented followed by a discussion of only the most recent work

  18. 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.

  19. 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.).

  20. Acoustic and optical investigations of superfluid 3He. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Manninen, A.

    1993-06-15

    The thesis is an experimental survey of properties of rotating and stationary superfluid (3)He. Two techniques, acoustics and optics, were used. Ultrasound, together with NMR, has provided most of the present experimental knowledge about the superfluid phases of (3)He. The author applied acoustics for the first time to study rotating (3)He. The main result was the discovery of a new vortex in (3)He-A when the magnetic field is low. New phenomena were observed in stationary (3)He as well. Most importantly, one of the collective modes, the real squashing (rsq) mode, of (3)He-B could be excited by means of two-phonon absorption. Superfluid (3)He was studied optically for the first time. No one has previously seen (3)He in the superfluid state. The principal achievement was developing techniques which facilitate optical experiments at temperatures below 1 mK, required to study superfluid (3)He. Optical fibers were used to transmit light between room temperature and the cold parts of the cryostat. Before these investigations, photography had not been done below 10 mK. The usefulness of optics as a proble of the superfluid phases of (3)He was demonstrated by studying the macroscopic shape of the free surface of rotating (3)He-B. The classical parabolic meniscus was observed, which is indicative of the equilibrium density of vortices.

  1. 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.

  2. Study of the {sup 9}Be(p,{alpha}){sup 6}Li reaction via the Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    Romano, S.; Lamia, L.; Spitaleri, C.; Cherubini, S.; Gulino, M.; La Cognata, M.; Tumino, A. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Universita di Catania, Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Catania (Italy); Li, C.; Pizzone, R.G. [INFN, Laboratori Nazionali del Sud, Catania (Italy)

    2006-03-15

    The Trojan Horse Method has been applied to the {sup 2}H({sup 9}Be,{sup 6}Li{alpha})n three-body reaction in order to investigate the {sup 9}Be(p,{alpha}){sup 6}Li two-body reaction, which is involved in the study of light element abundances (lithium, beryllium and boron). A coincidence measurement was performed in order to identify the presence of the quasi-free mechanism in the three-body reaction, needed for the application of the method. The astrophysical S(E)-factor was extracted and compared to direct data. No information about electron screening effects can be extracted due to the poor resolution of the indirect data. (orig.)

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

    International Nuclear Information System (INIS)

    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 6LiI(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 3He 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 3He 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. Photodisintegration of /sup 3/H and /sup 3/He. [Threshold to 25 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Faul, D.D.

    1980-09-01

    The photoneutron cross sections for /sup 3/H and /sup 3/He have been measured from threshold to approx. 25 MeV with monoenergetic photons from the annihilation in flight of fast positrons at the LLL Electron-Positron Linear Accelerator facility. These reactions include the two-body breakup of /sup 3/H and the three-body breakup of both /sup 3/H and /sup 3/He; these measurements for /sup 3/H are the first to span the energy region across the peaks of the cross sections. An efficient BF/sub 3/-tube-and-paraffin neutron detector and high-pressure gaseous samples of several moles each (the activity of the /sup 3/H sample was approx. 200,000 Ci) were employed in these measurements. Measurements on /sup 16/O and /sup 2/H also were performed to verify the absolute cross-section scale. The results, when compared with each other and with results for the two-body breakup cross section for /sup 3/He from the literature, show that the two-body breakup cross sections for /sup 3/H and /sup 3/He have nearly the same shape, but the one for /sup 3/He lies lower in magnitude; the three-body breakup cross section for /sup 3/He lies higher in magnitude and is broader in the peak region and also rises less sharply from threshold than that for /sup 3/H; and these measured differences between the cross sections for the breakup modes largely compensate in their sum, so that the total photon absorption cross sections for /sup 3/H and /sup 3/He are nearly the same in both size and shape at energies near and above their peaks. Theoretical results from the literature disagree with the experimental results to a certain extent over the entire photon-energy region for which the photoneutron cross sections were measured. 50 figures, 7 tables.

  5. 3He Neutron Spin Filter cell development program at JCNS

    International Nuclear Information System (INIS)

    In order to produce high-quality 3He Neutron Spin Filters (NSF) with a high polarisation level, it is necessary to achieve a long 3He relaxation time by the reduction of the wall relaxation. This requires one to minimise the amount of impurities at the surface of the glass cells, and to have as few contaminants as possible in the gas filling system. In this report we describe the detailed procedure we employ to produce 3He cells using our newly built filling station. The obtained life times for a number of cells are practically approaching the fundamental limit imposed by the dipole-dipole interaction between 3He atoms.

  6. Resonant and nonresonant Coulomb break up of 6Li

    International Nuclear Information System (INIS)

    The resonant and nonresonant cross section for break up of 6Li in the Coulomb field of a heavy nucleus is theoretically studied on the basis of a DWBA approach and analysed in view of a possible experimental access to electromagnetic transition matrix elements between the ground state of the projectile and α+d continuum states at small relative energies. The calculation explicitly uses some simplifications appearing in the particular case of quadrupole transitions which dominate the considered case. Various sensitivities of the cross sections are discussed. (orig.)

  7. Model formalism of liquid 3He-B at equilibrium

    International Nuclear Information System (INIS)

    The approximate formal treatment of the nuclear spin system of normal liquid 3He given some time ago is extended to the ordered 3He phase. The formalism leads to the prediction of normal thermal behavior of 3He-B at lower pressures and at temperatures approaching its phase-boundary temperatures. In contrast to the disordered normal liquid phase, which is thermally anomalous, the entropy of the 3He-B decreases on isothermal compression, or its isobaric volume expansion coefficient is positive. The equilibrium thermal behavior of ordered 3He-B is thus qualitatively different from that of disordered liquid 3He. Experimental control of these aspects of the liquid 3He phase transformation is lacking at the present time. Both early and new 3He-B paramagnetic susceptibility data, extended recently over a wide reduced-temperature range, disclose a fundamental competition between the spontaneous ordering mechanism responsible for the existence of 3He-B and the specific ordering process imposed upon this phase on application of an external constant and uniform magnetic field. As a consequence, magnetized 3He-B will be shown to increase its entropy on isothermal magnetization and to cool on adiabatic magnetization. The magnetocaloric effect is, however, only moderate. The competition of the ordering process leads to the delay or possibly even to the suppression of the formation of the ordered phase, a state of affairs foreseen in our earlier work. At low or moderate magnetic field strengths, the zero-field phase-boundary temperatures are shown to shift toward lower temperatures while, simultaneously, the order of the phase change decreases, from second order, in the absence of the field, to first order. Although of model-theoretic character, involving limitations of various types, the rich physical content of 3He-B at equilibrium clearly emerges in the present work

  8. 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 ...

  9. 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.

  10. 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.

  11. magnetic resonance of 3He nuclei in porous media

    International Nuclear Information System (INIS)

    The data on 3He spin kinetics in porous media above the Fermi temperature of 3He are summarized. Presented results are obtained in Kazan Federal University in last ten years and are the base of developing method of helium porometry. Guidelines for investigation of samples with unknown pore sizes and superficial their properties are proposed

  12. Measurement of the 2H(d ,p ) 3H reaction at astrophysical energies via the Trojan-horse method

    Science.gov (United States)

    Li, Chengbo; Wen, Qungang; Fu, Yuanyong; Zhou, Jing; Zhou, Shuhua; Meng, Qiuying; Spitaleri, C.; Tumino, A.; Pizzone, R. G.; Lamia, L.

    2015-08-01

    The study of the 2H(d ,p ) 3H reaction is very important for the nucleosynthesis in both the standard Big Bang and stellar evolution, as well as for the future fusion reactor's planning of energy production. The 2H(d ,p ) 3H bare nucleus astrophysical S (E ) factor has been measured indirectly at energies from about 400 keV down to several keV by means of the Trojan-horse method applied to the quasifree process 2H(6Li ,p t ) 4He induced at a lithium beam energy of 9.5 MeV, which is closer to the zero-quasifree-energy point. An accurate analysis leads to the determination of the Sbare(0 ) =56.7 ±2.0 keV b and of the corresponding electron screening potential Ue=13.2 ±4.3 eV. In addition, this work gives an updated test for the Trojan-horse nucleus invariance by comparing with previous indirect investigations using the 3He=(d +p ) breakup.

  13. Neutron spectrum measurements in CFRMF by 6Li spectrometry

    International Nuclear Information System (INIS)

    The neutron energy spectrum of the Couples Fast Reactivity Measurements Facility (CFRMF) has been measured by the 6Li(n,α)t spectrometry technique between the energies of 10 keV and 8 MeV. These measurements were made in order to improve the knowledge of this benchmark neutron field as related to dosimetry and other integral cross sections. Energy spectra of both the α + t and t responses were obtained simultaneously using two-parameter multichannel pulse height analysis. Spectrometers of different design and resolution characteristics were applied. The data were reduced using recently evaluated cross section information. The results are compared with the neutron spectrum calculated using recently evaluated cross section information. (author)

  14. Feasibility studies of D—3He fusion power in China

    Institute of Scientific and Technical Information of China (English)

    DengBai-Quan; FengKei-Ming; 等

    1997-01-01

    The systematic study on D-3He advanced fuel fusion in China has been performed.Comparisons between D-3He and D-T fuel cycles in physics,engineering,environmental safety and so on have been made.D-3He fusion offers significant adavantages for reducing the neutron yield by a factor of 10-60,The 3He resource and mining possibility are investigated.The energy payback factor of 97 for mining lunar 3He resource is calculated.The operating parameter scope for D-3He fueled Tokamak reactor is analyzed.The prompt energy broadening for fusion products is calculated and results are consistent with those obtained by Lehner using a different method.Centrally peaked current drive with high efficiency is studied utilizing plasma synchrotron radiation.Centrally peaked current drive with gigh efficiency is studied utilizing plasma synchrotron radiation.More than 80% of plasma current required can be driven passively.A D-3He fueled Tokamak commercial reactor-Mooncity was designed.Neutronics calculations show that the radioactivity,afterheat,BHP value for Mooncity are 10-60 times less than those for D-T fusion.

  15. D-3He fuel cycles for neutron lean reactors

    International Nuclear Information System (INIS)

    The intrinsic potential of D-3He as a reactor fuel is investigated for a large range of 3He to D density ratios. A steady-state zero-dimensional reactor model is developed in which much care is attributed to a proper treatment of fast fusion products. Useful ranges of reactor parameters as well as temperature-density windows for driven and ignited operation are identified. Various figures of merit are calculated, such as power densities, net power production, neutron production, tritium load and radiative power. These results suggest several optimistic conclusions about the performance of D-3He as a reactor fuel

  16. Magnetization and spin diffusion of liquid 3He in aerogel

    International Nuclear Information System (INIS)

    We report theoretical calculations and experimental measurements of the normal-state spin diffusion coefficient of 3He in aerogel, including both elastic and inelastic scattering of 3He quasiparticles, and compare these results with data for 3He in 98% porous silica aerogel. This analysis provides a determination of the elastic mean free path within the aerogel. Measurements of the magnetization of the superfluid phase in the same aerogel samples provide a test of the theory of pairbreaking and magnetic response of low-energy excitations in the 'dirty' B phase of 3He in aerogel. A consistent interpretation of the data for the spin-diffusion coefficient, magnetization, and superfluid transition temperature is obtained by including correlation effects in the aerogel density

  17. Safeguards Technology Factsheet 3He-free Neutron Coincidence Counter

    International Nuclear Information System (INIS)

    A full scale thermal neutron coincidence counter (High Level Neutron Counter - Boron: HLNB) based on 3He alternative detection technology was designed and built at LANL and field tested at Plutonium Conversion Development Facility (PCDF) of Japan Atomic Energy Agency (JAEA) during FY15. HLNB is based on boron-lined proportional plates that replace the traditional 3He proportional tubes and was designed as a direct alternative to 3He-based High Level Neutron Coincidence Counter (HLNC-II). During the JAEA field trial the HLNB demonstrated comparable performance to HLNC-II, which represents a key development in the area of 3He alternative technologies and provides a complete demonstration of the technology for nuclear safeguards applications including high mass MOX samples.

  18. 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.

  19. 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.

  20. Analytic vortices in rotating superfluid 3He-A

    International Nuclear Information System (INIS)

    Recent works on analytic vortices in rotating 3He-A are reviewed. It is shown that the circular-hyperbolic vortex lattice has the lowest free energy in an axial magnetic field. The associated nuclear magnetic resonance satellites account for not only the observed satellite frequencies in a rotating 3He-A experiment but also the observed intensity of the satellite resonances. 15 references, 3 figures

  1. 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.

  2. 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.

  3. 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...

  4. The (t,3He) and (3He,t) reactions as probes of Gamow-Teller strength

    CERN Document Server

    Zegers, R G T; Austin, S M; Bazin, D; Berg, G P A; Brown, B A; Cole, A L; Daito, I; Fujita, Y; Fujiwara, M; Galès, Sydney; Harakeh, M N; Hashimoto, H; Hayami, R; Hitt, G W; Howard, M E; Itoh, M; Jänecke, J; Kawabata, T; Kawase, K; Kinoshita, M; Nakamura, T; Nakanishi, K; Nakayama, S; Okamura, S; Richter, W A; Roberts, D A; Sherrill, B M; Shimbara, Y; Steiner, M; Uchida, M; Ueno, H; Van den Berg, A M; Yamagata, T; Yosoi, M; Austin, Sam M.

    2006-01-01

    Charge-exchange reactions are an important tool for determining weak-interaction rates. They provide stringent tests for nuclear structure models necessary for modeling astrophysical environments such as neutron stars and core-collapse supernovae. In this paper we demonstrate via a study of 26Mg(t,3He) that the (t,3He) reaction at 115 MeV/nucleon is an accurate probe for extracting Gamow-Teller strengths. This study is complemented by 26Mg(3He,t) data taken at 140 MeV/nucleon which allows for a comparison of T=2 analog states excited via the mirror reactions. A good correspondence is found between Gamow-Teller distributions measured via the 26Mg(3He,t) and 26Mg(p,n) experiments, indicating probe-independence of the strength extraction. Results from 26Mg(t,3He) and 26Mg(d,2He) also display good correspondence, showing that with the (t,3He) reaction a new tool has become available for studying Gamow-Teller strengths in the beta+ direction. Furthermore, we test shell-model calculations using the new USD-05B inte...

  5. Fast Neutron Detection with 6Li-loaded Liquid Scintillator

    CERN Document Server

    Fisher, B M; Coakley, K J; Gavrin, V N; Gilliam, D M; Nico, J S; Shikhin, A A; Thompson, A K; Vecchia, D F; Yants, V E

    2011-01-01

    We report on the development of a fast neutron detector using a liquid scintillator doped with enriched Li-6. The lithium was introduced in the form of an aqueous LiCl micro-emulsion with a di-isopropylnaphthalene-based liquid scintillator. A Li-6 concentration of 0.15 % by weight was obtained. A 125 mL glass cell was filled with the scintillator and irradiated with fission-source neutrons. Fast neutrons may produce recoil protons in the scintillator, and those neutrons that thermalize within the detector volume can be captured on the Li-6. The energy of the neutron may be determined by the light output from recoiling protons, and the capture of the delayed thermal neutron reduces background events. In this paper, we discuss the development of this 6Li-loaded liquid scintillator, demonstrate the operation of it in a detector, and compare its efficiency and capture lifetime with Monte Carlo simulations. Data from a boron-loaded plastic scintillator were acquired for comparison. We also present a pulse-shape di...

  6. 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.

  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. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Ultrasensitive 3He magnetometer for measurements of high magnetic fields

    CERN Document Server

    Nikiel, A; Heil, W; Hehn, M; Karpuk, S; Maul, A; Otten, E; Schreiber, L M; Terekhov, M

    2014-01-01

    We describe a 3He magnetometer capable to measure high magnetic fields (B > 0.1 Tesla) with a relative accuracy of better than 10^-12. Our approach is based on the measurement of the free induction decay of gaseous, nuclear spin polarized 3He following a resonant radio frequency pulse excitation. The measurement sensitivity can be attributed to the long coherent spin precession time T2* being of order minutes which is achieved for spherical sample cells in the regime of motional narrowing where the disturbing influence of field inhomogeneities is strongly suppressed. The 3He gas is spin polarized in-situ using a new, non-standard variant of the metastability exchange optical pumping. We show that miniaturization helps to increase T2* further and that the measurement sensitivity is not significantly affected by temporal field fluctuations of order 10^-4.

  13. Towards 6Li-40K ground state molecules

    International Nuclear Information System (INIS)

    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 6Li-40K 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 6Li-40K 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 of the resonance

  14. 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.

  15. Rotational quenching of CS in ultracold 3He collisions

    Science.gov (United States)

    Kaur, Rajwant; Dhilip Kumar, T. J.

    2016-08-01

    Quantum mechanical scattering calculations of rotational quenching of CS (v = 0) collision with 3He are performed at ultracold temperatures and results are compared with isotopic 4He collision. Rotational quenching cross sections and rate coefficients have been calculated in the ultracold region for rotational levels up to j = 10 using the He-CS potential energy surface computed at the CCSD(T)/aug-cc-pVQZ level of theory. The quenching cross sections are found to be two orders of magnitude larger for the 3He than the 4He isotope under ultracold conditions. Wigner threshold law is found to be valid below 10-3 K temperature.

  16. A measurement of the Panofsky ratio in 3He

    International Nuclear Information System (INIS)

    The nucleus 3He is one of the simplest nuclear systems; hence it is often used to study the complications introduced by the presence of additional nucleons on basic processes such as pion absorption on a free nucleon. 3He is the only nucleus for which both the pion charge exchange and radiative capture processes can occur at rest with reasonable probability. The ratio of these two processes is the well-known Panofsky ratio, P3 = ω(π-3He→π0T)/ω(π-+3He→γT). (orig./WL)

  17. Chiral effective field theory predictions for muon capture on deuteron and {3}He.

    Science.gov (United States)

    Marcucci, L E; Kievsky, A; Rosati, S; Schiavilla, R; Viviani, M

    2012-02-01

    The muon-capture reactions {2}H(μ{-},ν{μ})nn and {3}He(μ{-},ν{μ}){3}H are studied with nuclear potentials and charge-changing weak currents, derived in chiral effective field theory. The low-energy constants (LECs) c{D} and c{E}, present in the three-nucleon potential and (c{D}) axial-vector current, are constrained to reproduce the A=3 binding energies and the triton Gamow-Teller matrix element. The muon-capture rates on deuteron and {3}He are predicted to be 399±3  sec{-1} and 1494±21  sec{-1}, respectively. The spread accounts for the cutoff sensitivity, as well as uncertainties in the LECs and electroweak radiative corrections. By comparing the calculated and precisely measured rates on {3}He, a value for the induced pseudoscalar form factor is obtained in good agreement with the chiral perturbation theory prediction. PMID:22400928

  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. 3He-MRI of pulmonary ventilation: First clinical applications

    International Nuclear Information System (INIS)

    Purpose of the study is the visualisation of normal pulmonary ventilation in healthy volunteers and the evaluation of abnormalities in patients with different lung diseases using 3He magnetic resonance imaging (3He-MRI). Material und methods: Hyperpolarised 3He gas (V=300 ml, p=3x105 Pa, polarised to 35-45% by optical pumping, provided in special glass cells) was inhaled by eight healthy volunteers and ten patients with different lung diseases. A 3 D FLASH sequence (TR=11.8 ms; TE=5 ms; matrix 144x256, FOV 350 mm, section thickness 7-10 mm, coronal orientation) was performed in a single breath-hold (22-42 s). Clinical and radiological examinations were available for correlation. Results: The studies were successfully carried out in 8/8 volunteers and in 8/10 patients. The central airways were constantly visualised with intermediate to high signal instensity. The lung parenchyma of volunteers with normal ventilatory function showed rather homogeneous intermediate to high signal, whereas patients with chronic abstructive lung disease and/or pneumonia presented severe signal inhomogeneitises. Space-occupying lesions and pleural effusion caused large areas with little or no signal. The represented the lesion and adjacent ventilatory disturbances whose extent had not been presumed from chest X-ray or CT. The spatial resolution was higher than in ventilation scintigraphy. Conclusion: 3He MRI is a promising new modality for the assessment of pulmonary ventilation and its anormalies. (orig.)

  20. Theoretical description of deeply virtual Compton scattering off $^3$He

    CERN Document Server

    Rinaldi, Matteo

    2014-01-01

    Recently, coherent deeply virtual Compton scattering (DVCS) off $^3$He nuclei has been proposed to access the neutron generalized parton distributions (GPDs). In Impulse Approximation (IA) studies, it has been shown, in particular, that the sum of the two leading twist, quark helicity conserving GPDs of $^3$He, $H$ and $E$, at low momentum transfer, is dominated by the neutron contribution, so that $^3$He is very promising for the extraction of the neutron information. Nevertheless, such an extraction could be not trivial. A technique, able to take into account the nuclear effects included in the IA analysis in the extraction procedure, has been therefore developed. In this work, the IA calculation of the spin dependent GPD $\\tilde H$ of $^3$He is presented for the first time. This quantity is found to be largely dominated, at low momentum transfer, by the neutron contribution, which could be extracted using arguments similar to the ones previously proposed for the other GPDs. The known forward limit of the I...

  1. 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.

  2. 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.

  3. Functional {sup 3}He-MRI of the lungs; Funktionelle {sup 3}He-MRT der Lunge

    Energy Technology Data Exchange (ETDEWEB)

    Gast, K.K.; Wolf, U. [Universitaetsmedizin der Johannes-Gutenberg-Universitaet Mainz, Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie, Mainz (Germany)

    2009-08-15

    Pulmonary diseases have a high health-related and economic significance. {sup 3}He-MRI is an alternative imaging method which can detect ventilatory disturbances with a high sensitivity. The application of different pulse sequences allows static and dynamic assessment of ventilation and bronchial gas flow, non-invasive measurement of intrapulmonary oxygen partial pressure and quantification of pulmonary parenchyma destruction and overinflation. Generally, the method is applicable for obstructive and restrictive ventilatory disturbances but initial approaches also exist for vascular pulmonary diseases. Specific clinical applications remain to be determined but {sup 3}He-MRI is an excellent instrument for the assessment of physiologic and pathophysiologic interrelations in the distribution of ventilation. (orig.) [German] Lungenerkrankungen haben einen hohen gesundheitlichen und volkswirtschaftlichen Stellenwert. Die {sup 3}He-MRT ist eine alternative bildgebende Methode, die sensitiv Ventilationsstoerungen nachweisen kann. Ueber unterschiedliche Pulssequenzen koennen Ventilation und Gasfluesse statisch und dynamisch dargestellt, der intrapulmonale Sauerstoffpartialdruck nichtinvasiv gemessen und die Destruktion und Ueberblaehung des Lungenparenchyms quantifiziert werden. Prinzipiell ist die Methode fuer die Untersuchung obstruktiver und restriktiver Ventilationsstoerungen anwendbar, Ansaetze existieren jedoch auch fuer vaskulaere Lungenerkrankungen. Spezifische klinische Anwendungen fuer die {sup 3}He-MRT muessen noch erarbeitet werden, sie ist jedoch ein hervorragendes Instrument zur Untersuchung physiologischer und pathophysiologischer Zusammenhaenge bei der Ventilationsverteilung. (orig.)

  4. Development of {sup 6}LiF thermal neutron shield for PGNAA

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M. S.; Park, J. H.; Hong, K. W.; Jun, B. J. [KAERI, Taejon (Korea, Republic of); Bun, S. H.; Choi, H. D. [Seoul National Univ., Seoul (Korea, Republic of)

    2001-05-01

    The {sup 6}LiF tile which will be utilized as the neutron shield of the gamma ray detector at the prompt gamma neutron activation analysis facility of KAERI-HANARO is developed. The {sup 6}LiF powder is obtained by the reaction of hydrofluoric acid with the {sup 6}Li{sub 2}CO{sub 3} powder, and the yield of the {sup 6}LiF is 86% of the theoretical value. In order to fabricate the stable tile from toxic and irritant LiF powder, the optimum sintering procedure is developed using the LiF powder with naturally abundant {sup 6}Li. The sintering temperature is 720 .deg. C, and the heating rate is 120 .deg. C/h. The preliminary heating process at 500 .deg. C is added in fabricating the {sup 6}LiF tile. The density of fabricated LiF tile is 2.4{approx}2.5 g/cm{sup 3}, and it is above 90% of theoretical density. The density of fabricated {sup 6}LiF tile is 2.25 g/cm{sup 3}, and the neutron transmission rate is below 10{sup -8}, so the thermal neutron transmission is negligible. Therefore, the tile is confirmed to be useful for PGNAA facility.

  5. Direct measurement of the spin-dependent capture and scattering of slow neutrons by 6Li

    International Nuclear Information System (INIS)

    The spin-dependent capture cross section sigma/sup c//sub +/-sigma/sup c//sub -/ of slow neutrons (lambda = 1.074 A) by 6Li has been determined from the flipping ratio of a transmitted polarized neutron beam as a function of 6Li polarization. We used two methods, one of which also enabled us to measure the spin-dependent scattering length b/sub +/-b/sub -/ of 6Li. We find sigma/sub +//sup c/-sigma/sub -//sup c/ = -1170 +- 50 b and b/sub +/-b/sub -/ = (-0.38 +- 0.05) x 10-12 cm

  6. Spin-dipole excitations of 6Li in charged pion photoproduction

    International Nuclear Information System (INIS)

    In the framework of bound shell model the photoproduction cross sections of charged pions on 6Li are calculated when spin-isospin dipole resonance is excited. It is shown that the transition strenqth concentrates in several energy regions. Such a gross-structure of the excitation spectrum is gaverned by the confiqurational splittinq of the resonance. The excitation spectrum in 6Li(γ, π)-reaction is compared with the 6Li(π, γ), (e, e') and (n, p) reaction spe;tra where spin-isospin transitions are dominating too

  7. 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)

  8. 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$_1$.

  9. 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)).

  10. Photoassociation spectroscopy of ultracold metastable ^3He dimers

    CERN Document Server

    Cocks, Daniel G; Whittingham, Ian B

    2011-01-01

    The bound states of the fermionic ^3He(2 ^3S_1)+ ^3He(2 ^3P_j)system, where j=0,1,2, are investigated using the recently available ab initio short-range ${}^{1,3,5}\\Sigma^{+}_{g,u}$ and ${}^{1,3,5}\\Pi_{g,u}$ potentials computed by Deguilhem et al. (J. Phys. B: At. Mol. Opt. Phys., 2009, 42, 015102). Single-channel and multichannel calculations have been undertaken in order to investigate the effects of Coriolis and non-adiabatic couplings. The possible experimental observability of the theoretical levels is assessed using criteria based upon the short-range character of each level and their coupling to metastable ground states. Purely long-range levels have been identified and 30 short-range levels near five asymptotes are suggested for experimental investigation.

  11. Studies of 3He Induced Nuclear Reactions on Cadmium

    International Nuclear Information System (INIS)

    Excitation functions of 3He induced nuclear reactions on natural cadmium were measured using the standard stacked foil technique and high resolution gamma ray spectroscopy. The experimental cross sections for the nuclear reactions natCd(3He,xnp )117m,g,116m115m,114m,113m,111,110m,g,109,108,107 In were measured from their threshold energy up to 27 MeV. The integral yields for some medically important products were determined. Theoretical calculations using the nuclear codes ALICE- IPPE, TAL YS, and EMPIRE-3 were used to describe the formation of these products. Theoretical and experimental results were compared with each other. K

  12. A polarized sup 3 He internal target for storage rings

    CERN Document Server

    Poolman, H R; Bulten, H J; Doets, M; Ent, R; Ferro-Luzzi, M; Geurts, D G; Harvey, M; Mul, F A

    2000-01-01

    A polarized sup 3 He internal target was employed at the internal target facility of the Amsterdam electron Pulse Stretcher and Storage ring (AmPS) at the Dutch National Institute for Nuclear and High-Energy Physics (NIKHEF). The unique features of internal targets such as chemical and isotopic purity, high and rapidly reversible polarization, and the ability to manipulate the target spin orientation were successfully demonstrated. A nuclear polarization of 0.50 (0.42) at a sup 3 He gas flow of 1.0 (2.0)x10 sup 1 sup 7 at s sup - sup 1 could be obtained. Operation at a nominal flow of 1x10 sup 1 sup 7 at s sup - sup 1 resulted in a target thickness of 0.7x10 sup 1 sup 5 at cm sup - sup 2 at a target temperature of 17 K.

  13. Fluctuations above the superfluid transition in liquid 3He

    International Nuclear Information System (INIS)

    It is shown that fluctuations above the superfluid transition in liquid 3He depend strongly upon the relative angular momentum l of a Cooper pair but are insensitive to the fourth order term in the Ginsburg-Landau free energy. The effects are shown to be observable in the static magnetization, viscosity and spin diffusion and give a means of determining the value of l. (U.S.)

  14. 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.

  15. Orbital angular momentum in /sup 3/He-A-italic

    Energy Technology Data Exchange (ETDEWEB)

    Balatskii-breve, A.V.; Mineev, V.P.

    1985-12-01

    The intrinsic angular momentum in the A-italic phase of superfluid /sup 3/He is found in terms of the response to the angular velocity of rotation. It is shown that in the weak-coupling approximation at an arbitrary temperature and with allowance for the Fermi-liquid renormalization the intrinsic angular momentum is small in accordance with the smallness of the asymmetry in the distribution of particles and holes.

  16. 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 ...

  17. High Efficiency Spin Flipper for the n3He Experiment

    Science.gov (United States)

    Hayes, Christopher; n3He Collaboration

    2015-10-01

    The n3He experiment, constructed on the Fundamental Neutron Physics Beamline (FnPB) at the Spallation Neutron Source, is designed to measure the parity violating (PV) proton asymmetry Ap in the capture reaction n +3 He -->3 H + p + 765 keV The asymmetry has an estimated value Ap ~ - 1 ×10-7 and is directly related to the weak isospin conserved couplings hρ0 and ωρ0 which are of fundamental interest in the verification of the meson exchange model of low energy NN intereactions. Data production for the n3He experiment began in February 2015 and is scheduled to continue thru December 2015 - reaching a statistical sensitivity δAp ~10-8 or better. I will discuss the spin flipper which is designed using the theory of double cosine-theta coils, and capable of flipping neutron spins with an efficiency approaching its maximum value ɛsf = 1 . I will also discuss the theory of Spin Magnetic Resonance (SMR) and how it is employed by the spin flipper to flip 60 Hz pulses of cold neutrons over a range of wavelengths.

  18. Effects of nuclear breakup channel on fusion of 6Li+64Zn system around barrier energies

    International Nuclear Information System (INIS)

    We have studied the effects of breakup, occurring due to the nuclear interaction between weakly bound 6Li and tightly bound 64Zn isotopes, on the fusion reaction at near barrier energies within the framework of dynamic polarization potential (DPP) approach. When the nuclear induced dynamic polarization potential is taken into account sub barrier enhancement and above barrier suppression have been found which improves the matching between the fusion excitation function data and predictions for 6Li+64Zn system significantly. (author)

  19. Lines in the spectrum of 6LiH (2985--5158 A)

    International Nuclear Information System (INIS)

    The emission spectra of the A1Σ+--X1Σ+ bands of 6LiH were photographed in the 2985 - 5158 A region with a 3.4 meter Ebert Spectrograph of theoretical resolution of about 0.07 cm-1. High-purity 6LiH crystals were obtained from Oak Ridge National Laboratory. The atomic percent of 6Li in 6LiH was 95.58 percent. The discharge source was a demountable stainless steel hollow cathode lamp. The lithium hydride crystals were packed into the cathode. Pressure in the discharge tube was about 10 to 20 torr of H2. The disharge was run at about 600 volts and 1.25 to 1.75 amperes. Acceptable spectra were obtained with exposure time of 6 hours. A Westinghouse iron hollow cathode was used to produce the iron spectrum for calibration. The plates were measured on the Gaertner photoplate comparator with an encoder system and on-line computer service at Argonne National Laboratory. The measured lines in the spectra of 6LiH are given in this report (COO-2326-17). Similar spectra for 6LiD and 7LiH are given in companion reports (COO-2326-18) and (COO-2326-19), respectively. The relative intensities of the lines are applicable only to short regions and do not extend over the whole spectrum

  20. Lines in the spectrum of 6LiD (3086--5156 A)

    International Nuclear Information System (INIS)

    The emission spectra of A1Σ+--X1Σ+ bands of 6LiD were photographed in the 3086 A - 5156 A region with a 3.4 meter Ebert Spectrograph of theoretical resolution of about 0.07 cm-1. High-purity 6LiD crystals were obtained from Oak Ridge National Laboratory. The atomic percent of 6Li in 6LiD was 95.58 percent. The discharge source is a demountable stainless steel hollow cathode lamp. The lithium deuteride crystals were packed into the cathode. Pressure in the discharge tube was about 10 to 20 torr of D2. The discharge was run at about 600 volts and 1.25 to 1.75 amperes. Acceptable spectra were obtained with exposure time of 6 hours. A Westinghouse iron hollow cathode was used to produce the iron spectrum for calibration. The plates were measured on the Gaertner photoplate comparator with an encoder system and on-line computer service at Argonne National Laboratory. The measured lines in the spectra of 6LiD are given in this report (COO-2326-18). Similar spectra for 6LiH and 7LiH are given in companion reports (COO-2326-17) and (COO-2326-19), respectively. The relative intensities of the lines are applicable only to short regions and do not extend over the whole spectrum

  1. Vortex clusters in superfluid 3He-B

    International Nuclear Information System (INIS)

    A unique property of 3He-B is vortex-free rotation, due to a high nucleation threshold of the singular vortices. In contrast to other superfluids, rotational states consisting of a vortex cluster surrounded by vortex-free counterflow form spontaneously and can also be prepared with a fixed number of vortices. The clusters can be analyzed by means of NMR measurements with high precision. These techniques have been exploited to study rotational states in the presence of different phase boundaries. (orig.)

  2. 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.

  3. Neutron scattering from liquid {sup 3}He at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Guckelsberger, K. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Azuah, R.T. [Department of Physics, Keele University, Keele Staffordshire, ST5 5BG (United Kingdom)]|[Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0Qx (United Kingdom); Stirling, W.G. [Keele University (United Kingdom); Bennington, S.M.; Yates, M. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0Qx (United Kingdom)

    1997-06-01

    Understanding the dynamics of strongly interacting quantum liquids is at the heart of much of contemporary physics and the archetypal Fermi liquid is {sup 3}He at low temperatures. However, due to the enormous absorption of neutrons by {sup 3}He, experiments are exceedingly difficult. At very high incident neutron energies (>1 eV), the struck atoms behave as if they were free. In a sense, one can ``switch on the interaction`` by using neutrons with ever lower energies until they are-near 1 meV-comparable to that of the interaction. In the present work we use 80-400 meV neutrons to resolve a long standing puzzle: previous measurements suggested strong fluctuations in the width of the recoil peak that could not be understood in terms of a simple theory. Using improved instrumentation (MARI at the spallation source) and novel sample cell design we could improve statistics by more than one order of magnitude. The new data covering an extended energy range are presented and seem to confirm the theory. (orig.).

  4. 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.

  5. Global optical model potentials for symmetrical lithium systems: 6Li+6Li, 7Li+7Li at Elab = 5-40 MeV

    International Nuclear Information System (INIS)

    Angular distributions of 6Li+6Li elastic scattering were measured for Elab=5-40 MeV. An optical model analysis of these data together with older data of 7Li+7Li elastic scattering taken at Elab = 8-17 MeV was performed with the aim to search for a ''global'' OM potential which describes elastic scattering in both Li-Li systems in a broad energy range. Both surface and volume absorbing potentials can be found which fulfill this requirement if a linear energy dependence is assumed of the depths of the real as well as the imaginary potential. These depths, if fitted to individual angular distributions, are found to vary in a correlated manner with the beam energy. This is taken as indication of strong coupling between elastic, inelastic, and reaction channels. This is corroborated by the existence of resonances in reaction channels at these energies where the potential depths are most pronouncedly changing. (orig.)

  6. A dynamic model for power deposition in 3He lasers pumped by 3He(n,p) 3H reactions

    Science.gov (United States)

    Çetin, Füsun

    2004-07-01

    The coupled variation of power density with gas density in a nuclear-pumped laser, which is excited by 3He(n,p) 3H reaction products, is considered. In the literature, volumetric excitation by reaction products of 3He(n,p) 3H is only considered for the case in which gas density is uniform and does not change during the pumping. In this work, a time-dependent model describing the coupled fluid dynamic and particle transport behaviour of the gas has been developed. In modelling charge particle transport behaviour, a previously reported energy deposition model for a constant gas density is extended for a variable gas density by taking into account variations in the particle range, macroscopic cross sections and neutron flux depending on density field of the gas. The coupled equations, which are obtained by using the power deposition density expression obtained for variable gas density in the acoustically filtered equations of motion of the gas, are solved numerically. Spatial and temporal variations of power deposition density and gas density during the pumping pulse are determined for various operating pressures ranging from 0.5 to 10 atm. In the calculations, the characteristics of I.T.U TRIGA Mark-II Reactor are used and it is assumed that laser tube is placed in the centre of the reactor core. Obtained results are presented and examined.

  7. 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.

  8. 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.

  9. Realization of administration unit for 3He with gas recycling

    International Nuclear Information System (INIS)

    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 (3He,129Xe) 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.

  10. Nuclear spin dynamics in solid 3He at ultralow temperatures

    International Nuclear Information System (INIS)

    In this thesis the experimental study of the spin dynamics of solid 3He is described. By means of magnetization measurements above 3 mK a Curie-Weiss behaviour was found with θW∼2.1 mK and by this an order parameter of J=θWkB/∼-0.5 KkB was observed, while in the range of 1 to 3 mK a pure Curie behaviour was found. By means of NMR measurements the values of τ1(6 mK)=240 ms±12 ms and τ1(1 mK)∼ 40 ms were determined, while spin-echo measurements yielded the spin-spin relaxation time τ2(6 mK)=4540 μs±140 μs. Furthermore neutron scattering studies were performed. (HSI)

  11. Vortex structure in rotational state superfluid 3He

    International Nuclear Information System (INIS)

    The structure of vortices in rotational superfluid 3He is considered. It is marked that in the A-phase quantum vortices are possible, in which the A-phase superfluid state is never disturbed. As a consequence of a discrete combined invariance (calibration transformation plus rotation of a spin subsystem) one more exotic type of vortices is possible in the A-phase. This is a hybrid of disclination in a magnetic anisotropy vector field d (with a half-integer Frank index) and vortex that possesses a half-integer number of circulation quanta. Such vortices can be observed at rotation of the A-phase confined between parallel plates. The vortex properties in the B-phase are determined by a continuous combined symmetry. The calculations show the vortex in the β-phase at low pressures to be in the ν-state. The vortices considered are observed in the NMR experiments

  12. Muon capture on the deuteron and 3He

    Directory of Open Access Journals (Sweden)

    Elmeshneb A. E.

    2014-01-01

    Full Text Available We plan to investigate the role of meson exchange currents in the description of the µ− + d → νµ + n + n and µ− + 3He → νµ + 3H reactions. They both are treated as the decay of the corresponding muonic atoms, with the muon initially on the lowest K shell. The muon binding energy in these atoms can be safely neglected and in the initial state we deal essentially with the deuteron (or 3He and muon at rest. These two reactions are interesting for several reasons. First of all, they offer a testing ground for the nuclear wave functions, which for any nucleon-nucleon (NN and three-nucleon (3N forces can be constructed for such light systems with great accuracy. In these reactions few-nucleon weak current operators are an important dynamical ingredient. In the current operators apart from the relatively well known single nucleon contributions, two-nucleon parts (generated by various meson exchanges play an important role. Their details are not well known and several models should be considered. We present our formalism for dealing with these reactions and a simple method for partial wave decomposition of the two-nucleon operators. The crucial nuclear matrix elements of the corresponding weak current operators will be calculated in the momentum space and using partial wave decomposition. The effect of meson exchanges will be investigated in the energy spectrum of the emitted neutrinos (in the deuteron case and in the total decay rates for the two reactions. We will employ various models of NN and 3N forces, such as the Bonn B or chiral NNLO potentials. Our results with the single nucleon currents look already very promising and we hope for the improvement in the description of the experimental data, when dominant two-nucleon current operators are included in our framework.

  13. Study of direct and sequential break-up reactions in 6Li+ 112Sn system

    International Nuclear Information System (INIS)

    The 6Li projectile while moving in the field of a target nucleus can not only dissociate into α+d but it can also first exchange a few nucleon with the target and then break up into two fragments. Identification of all these processes is important to understand the break-up mechanism of 6Li projectile and also to find the origin of the high yield of alpha particle production in such a reaction. In this paper, we present the exclusive measurement of breakup cross sections in 6Li+112Sn reaction exploring the above possibilities. Cross sections for both sequential as well as direct breakup are measured and compared with the theoretical calculations. The measured elastic scattering angular distributions were used as a constraint to the potential parameters that were used in the calculations to explain both elastic scattering and the breakup processes simultaneously

  14. 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.

  15. 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.

  16. The In Situ Polymerization and Characterization of PA6/LiCl Composites

    Directory of Open Access Journals (Sweden)

    Dandan Sun

    2013-01-01

    Full Text Available PA6/LiCl composites were synthesized by in situ anionic polymerization based on the interaction between the inorganic salts and PA6. Sodium hydroxide as initiator and N-acetylcaprolactam as activator were used in the preparation of PA6/LiCl composites with variety of LiCl content. X-ray diffraction (XRD and differential scanning calorimeter (DSC testing results showed that both of degree of crystallinity and melting temperature of the composites were decreased under the influence of LiCl. And the γ crystal phase proportion increased with increasing the LiCl content to appropriate amount.

  17. 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.

  18. Nuclear spin dynamics in solid {sup 3}He at ultralow temperatures; Kernspindynamik in festem {sup 3}He bei ultratiefen Temperaturen

    Energy Technology Data Exchange (ETDEWEB)

    Kath, Matthias

    2009-11-06

    In this thesis the experimental study of the spin dynamics of solid {sup 3}He is described. By means of magnetization measurements above 3 mK a Curie-Weiss behaviour was found with {theta}{sub W}{approx}2.1 mK and by this an order parameter of J={theta}{sub W}k{sub B}/{approx}-0.5 Kk{sub B} was observed, while in the range of 1 to 3 mK a pure Curie behaviour was found. By means of NMR measurements the values of {tau}{sub 1}(6 mK)=240 ms{+-}12 ms and {tau}{sub 1}(1 mK){approx} 40 ms were determined, while spin-echo measurements yielded the spin-spin relaxation time {tau}{sub 2}(6 mK)=4540 {mu}s{+-}140 {mu}s. Furthermore neutron scattering studies were performed. (HSI)

  19. Role of projectile breakup in {sup 6}He and {sup 6}Li induced fusion reactions around barrier energies

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Anju; Kharab, Rajesh, E-mail: kharabrajesh@rediffmail.com

    2015-09-15

    The influence of projectile breakup on fusion cross section for {sup 6}He + {sup 209}Bi, {sup 6}He + {sup 64}Zn, {sup 6}Li + {sup 209}Bi and {sup 6}Li + {sup 64}Zn reactions at near barrier energies is studied within the framework of quantum diffusion approach. The breakup does not affect the fusion induced by {sup 6}He, whereas a significant suppression for {sup 6}Li induced reaction is observed in below barrier energy region.

  20. NMR studies on vortices in rotating 3He-A

    International Nuclear Information System (INIS)

    NMR measurements are reported on rotating 3He-A in a long cylindrical geometry of 5 mm diameter at a liquid pressure of 29.3 bar and in axial magnetic fields of 14.2, 28.4, and 56.9 mT. At 28.4 mT, NMR studies are also reported in fields inclined by 250 and 900 from the axis of rotation. The frequency shift, the width, and the intensity of the spin wavemodes localized on the soft vortex cores, as well as the additional broadening of the main NMR line during rotation, were measured as a function of temperature, angular velocity Ω, magnetic field intensity, and its inclination angle. Also observed were a critical angular velocity of vortex formation, hysteretic behavior in the number of vortices when comparing accelerating rotation to decelerating, and metastable vortex densities, presumably a vortex tangle after rapid oscillatory acceleration. The results can be understood in terms of the continuous 4π vortices first proposed by Seppaelae and Volovik

  1. Vortex sheet in superfluid 3He-A

    International Nuclear Information System (INIS)

    A new state of rotating superfluid 3He-A has been found recently. Usually superfluids respond to rotation by creating an array of vortex lines, which are parallel to the rotation axis, and the circulation around them is quantized. In the new state the vorticity is located on a 2 dimensional sheet instead of 1 D lines. The sheet is parallel to the rotation axis z but in the x - y plane it folds to equidistant layers. The distance between the layers is larger but on the same order of magnitude as the distance between vortex lines. In contrast to other superfluids, the sheet is stable in the A phase because, of its internal structure. The sheet has as a backbone a topologically stable domain wall called soliton, to which non-singular vorticity is bound. Thus it can exist in spite of its presumably higher energy. The vortex sheet is distinguished by its NMR response, in particular because of its higher absorption at a characteristic frequency. Experiment and theory on the vortex sheet are in good agreement

  2. 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).

  3. 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

  4. Optical model studies of 6Li elastic scattering at 156 MeV

    International Nuclear Information System (INIS)

    Differential cross sections for 6Li elastic scattering at 156 MeV from 12C, 40Ca 90Zr and 208Pb are presented. The sensitivity to various potential forms is established by using Saxon Woods, Saxon-Woods-squred, density independent and density dependent folded potentials. The extent to which the experimental data determine the potentials and related quantities is discussed. (orig.)

  5. Transfer Excitation Processes Observed in N3+-He and O3+-He Collisions at Elab = 33 eV

    Science.gov (United States)

    Itoh, Yoh

    2016-09-01

    We measured the relative state-selective differential cross sections (DCSs) for one-electron capture reactions using a crossed-beam apparatus. The scattering angle θlab studied in the laboratory frame ranged from -3.0 to 22° and the laboratory collision energy Elab was 33 eV. Only the transfer excitation processes, i.e., the electron capture reactions with the simultaneous excitation of the projectile, were observed. The DCSs were determined for the following reactions: N3+ (1s2 2s2 1S) + He (1s2 1S) → N2+ (1s2 2s2p2 2D) + He+ (1s 2S) + 10.3 eV, O3+ (1s2 2s2 2p 2P) + He (1s2 1S) → O2+ (1s2 2s 2p3 3P) + He+ (1s 2S) + 12.7 eV, and O3+ (1s2 2s2 2p 2P) + He (1s2 1S) → O2+ (1s2 2s 2p3 3D) + He+ (1s 2S) + 15.5 eV. In the N3+-He system, the DCSs for the reaction are zero at the center-of-mass angle θcm = 0 and show a peak at a certain angle and a shoulder at a larger angle. In the O3+-He system, the DCSs are again zero at θcm = 0. The capture process to the O2+ (1s2 2s 2p3 3P) state is mainly observed at smaller scattering angles, and the reaction to the O2+ (1s2 2s 2p3 3D) state becomes dominant with increasing scattering angle. A classical trajectory analysis within the two-state approximation based on the ab initio potentials for (NHe)3+ revealed that the transfer excitation of a two-electron process takes place through a single crossing of the relevant potentials.

  6. Economic evaluation of D-T, D-3He, and catalyzed D-D fusion reactors

    International Nuclear Information System (INIS)

    Because the D-3He reaction generates no neutrons and the D-D reaction can use abundant fuel resources, these reactions are expected to be used in advanced fuel fusion reactors. Economic considerations and engineering problems are important for realizing such reactors as commercial plants. Therefore, we estimate and compare the cost of electricity (COE) from D-T, D-3He, and catalyzed D-D (cat D-D) fusion reactors. D-3He and cat D-D reactors have a low neutron wall load. Therefore, the D-3He reactor has no wall replacement cost. In addition, no tritium breeding system is needed for the D-3He reactor, but 3He gas is rare. Because the reaction rates of the D-3He and D-D reactions are less, D-3He and D-D reactors require highly efficient confinement properties and operation at high ion temperatures. Furthermore, the power densities of D-3He and D-D reactors are smaller than that of the D-T reactor; thus, D-3He and D-D reactors require a large plasma volume. Assuming a high ion temperature (= 60 keV) and high normalized beta (= 7-8), the COE of a D-3He reactor is expected to be similar to that of a D-T reactor. In terms of cost, cat D-D is disadvantageous in comparison with D-3He and D-T reactors. (author)

  7. 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.

  8. Requirements for charged-particle reaction cross sections in the d-d, d-t, t-t, and d-3He fuel cycles

    International Nuclear Information System (INIS)

    This paper reviews the status of experimental data and data evaluations for charged-particle reactions of interest in fusion-reactor design. In particular, the 2H(t,α)n, 2H(d,p)3H, 2H(d,3He)n, 3H(t,α)nn and 3He(d,p)4He reactions at low energies are studied. Other secondary reactions are considered. The conclusion is that such cross sections are well known for the near and medium term, and that no crucial experimental lack exists. There is a serious lack of standard evaluations of these reactions, which should be in an internationally acceptable format and easily accessible. Support for generating such evaluations should be given serious consideration

  9. 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...

  10. 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.

  11. Investigation of adsorption and wetting of 3He on cesium and cesiated glass

    International Nuclear Information System (INIS)

    Experiments have been carried out to investigate the binding of 3He on cesium substrates, using optical pumping to spin-polarize the atoms. The behavior of 3He on the walls at low temperature can be analyzed through the evolution of the nuclear magnetization of the sample. Preliminary results are presented, including: (1) adsorption studies of gaseous 3He on cesiated glass; (2) magnetic relaxation time of polarized liquid 3He on cesium and cesiated glass; (3) evidence for wetting of liquid 3He on cesium. 8 refs., 2 figs

  12. 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.

  13. Neutron assay in mixed radiation fields with a 6Li-loaded plastic scintillator

    International Nuclear Information System (INIS)

    A novel technique for assay of thermal and fast neutrons in a 6Li-loaded plastic scintillator is presented. Existing capture-gated thermal neutron detection techniques were evaluated with the 6Li-loaded plastic scintillator studied in this work. Using simulations and experimental work, shortcomings in its performance were highlighted. As a result, it was proposed that by separating the combined fast and thermal neutron events from gamma events, using established pulse shape discrimination techniques, the thermal neutron events could then be assayed. Experiments were conducted at the National Physical Laboratory, Teddington, performing neutron assays with seven different neutron fields using the proposed technique. For each field, thermal and fast neutron content was estimated and were shown to corroborate with the seven synthesised fields

  14. Measurement of the 1H(6He,6Li)n reaction in inverse kinematics

    International Nuclear Information System (INIS)

    The 1H(6He,6Li)n reaction was studied at 0 degree with the NSCL A1200 fragment separator in the energy loss mode. A 6He secondary beam at E/A=93 MeV was used to measure the Gamow-Teller and Fermi strengths between the ground state of 6He and the ground and excited states of 6Li, in inverse kinematics. At 0 degree the ground-state cross section is measured to be dσGS/(dΩ)=43±16 mb/sr, which is dominated by systematic error in the secondary beam flux. The ratio of Gamow-Teller to Fermi strength is not sensitive to this error and is found to be (87±6)% of that expected from (p,n) systematics and β decay. Angular distributions have been measured between 0 degree and 10 degree in the center of mass. copyright 1996 The American Physical Society

  15. 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.

  16. Investigation of the selection of the selectively heated ions of 6Li isotope from lithium plasma

    International Nuclear Information System (INIS)

    Results of experiments on preparation of enriched lithium by means of plasma isotope separation method using ion cyclotron resonance (ICR) are presented. Two types of collectors were compared: cylindrical and plane ones. Both collectors were placed just as in homogeneous magnetic field immediately after the zone of selective ICR heating, so in diverging weakened one, closer to solenoid end. In cylindrical collector higher lithium enrichment by 6Li (up to 83 %) is observed. That corresponds to distribution coefficient ≅60

  17. BEC of 41 K in a Fermi sea of 6 Li

    Science.gov (United States)

    Lous, Rianne S.; Fritsche, Isabella; Huang, Bo; Jag, Michael; Cetina, Marko; Walraven, Jook T. M.; Grimm, Rudolf

    2016-05-01

    We report on the production of a 41 K Bose-Einstein condensate (BEC) immersed in a degenerate two-component 6 Li Fermi sea. After evaporation in an optical dipole trap, we obtain 1 . 2 ×104 41 K atoms with a 55% BEC fraction and a Fermi sea with T /TF work is supported by the Austrian Science Fund FWF within the collaborative research grant FoQuS.

  18. Development of a mini high efficiency neutron detector based on 6LiI (Eu) scintillator

    International Nuclear Information System (INIS)

    A mini neutron detector with the dimension of φ25 mm ×20 mm is developed based on a 6LiI( Eu) scintillator with a Hamamatsu S3590-08 photodiode. The detector was used to detect thermal neutrons from a paraffin shielded 252Cf neutron source and the detect efficiency to thermal neutron was calculated to be 95% with a resolution of thermal neutron peak about 16%. (authors)

  19. 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.

  20. Measurement of interaction energy near a Feshbach resonance in a 6Li Fermi gas

    OpenAIRE

    Bourdel, T; Cubizolles, J.; Khaykovich, L.; Magalhaes, K. M. F.; Kokkelmans, S. J. J. M. F.; G. V. Shlyapnikov; Salomon, C

    2003-01-01

    We investigate the strongly interacting regime in an optically trapped $^6$Li Fermi mixture near a Feshbach resonance. The resonance is found at $800(40) $G in good agreement with theory. Anisotropic expansion of the gas is interpreted by collisional hydrodynamics. We observe an unexpected and large shift ($80 $G) between the resonance peak and both the maximum of atom loss and the change of sign of the interaction energy.

  1. Understanding the effect of channel coupling on fusion of 6Li+64Ni

    Science.gov (United States)

    Moin Shaikh, Md.; Roy, Subinit

    2016-07-01

    The effect of inelastic excitation and single particle transfer reactions on fusion have been investigated for the system 6Li+64Ni at near barrier energies. The calculations show that a simultaneous coupling to the inelastic excitation of projectile and target along with positive Q-value 1n- and 1p-stripping channels, describes the experimental CF cross sections reasonably well in the below barrier region.

  2. THE NEW DETECTIONS OF 7Li/6Li ISOTOPIC RATIO IN THE INTERSTELLAR MEDIA

    International Nuclear Information System (INIS)

    We have determined the isotopic abundance ratio of 7Li/6Li in the interstellar media (ISMs) along lines of sight to HD169454 and HD250290 using the High-Dispersion Spectrograph on the Subaru Telescope. We also observed ζ Oph for comparison with previous data. The observed abundance ratios were 7Li/6Li = 8.1+3.6-1.8 and 6.3+3.0-1.7 for HD169454 and HD250290, respectively. These values are in reasonable agreement with those observed previously in the solar neighborhood ISMs within ±2σ error bars and are also consistent with our measurement of 7Li/6Li = 7.1+2.9-1.6 for a cloud along the line of sight to ζ Oph. This is good evidence for homogeneous mixing and instantaneous recycling of the gas component in the Galactic disk. We also discuss several source compositions of 7Li, Galactic cosmic-ray interactions, stellar nucleosynthesis, and big bang nucleosynthesis.

  3. Experimental study of fusion neutron and proton yields produced by petawatt-laser-irradiated D2-3He or CD4-3He clustering gases

    CERN Document Server

    Bang, W; Bonasera, A; Quevedo, H J; Dyer, G; Bernstein, A C; Hagel, K; Schmidt, K; Gaul, E; Donovan, M E; Consoli, F; De Angelis, R; Andreoli, P; Barbarino, M; Kimura, S; Mazzocco, M; Natowitz, J B; Ditmire, T

    2013-01-01

    We report on experiments in which the Texas Petawatt laser irradiated a mixture of deuterium or deuterated methane clusters and helium-3 gas, generating three types of nuclear fusion reactions: D(d, 3He)n, D(d, t)p and 3He(d, p)4He. We measured the yields of fusion neutrons and protons from these reactions and found them to agree with yields based on a simple cylindrical plasma model using known cross sections and measured plasma parameters. Within our measurement errors, the fusion products were isotropically distributed. Plasma temperatures, important for the cross sections, were determined by two independent methods: (1) deuterium ion time-of-flight, and (2) utilizing the ratio of neutron yield to proton yield from D(d, 3He)n and 3He(d, p)4He reactions, respectively. This experiment produced the highest ion temperature ever achieved with laser-irradiated deuterium clusters.

  4. Interferometric and acoustic measurements in superfluid (3)He-B and wetting studies in (3)He/(4)He mixtures. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Alles, H.

    1995-06-22

    In this thesis work superfluid (3)He was investigated by two methods. First, ultrasonic experiments on (3)He-B were carried out using two coincident zero sound pulses. The second technique is optics, a novel method for ultra low temperatures. The developed method, two-beam interferometry, was employed successfully for studies of wetting phenomena in liquid (3)He/(4)He mixtures as well. This publication contains the results of a acoustic spectroscopy on (3)He-B. Most importantly, the real squashing collective mode (rsq) was excited by two simultaneous sound pulses yielding two phonon absorption (TPA). This nonlinear phenomenon was applied to study the dispersion relation of the rsq-mode. Zeeman splitting of the nonlinearly excited rsq-mode was investigated in a magnetic field. By means of TPA, an anomalous behavior was found also near the pair-breaking edge.

  5. 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.

  6. 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.

  7. Density dependence of the single particle kinetic energy in {sup 3}He-{sup 4}He

    Energy Technology Data Exchange (ETDEWEB)

    Azuah, R.T. [Keele Univ. (United Kingdom). Dept. of Physics]|[Rutherford Appleton Lab., Chilton, Didcot (United Kingdom); Stirling, W.G. [Keele Univ. (United Kingdom). Dept. of Physics; Gibbs, M.R. [Keele Univ. (United Kingdom). Dept. of Physics; Sokol, P.E. [Dept. of Physics, Pennsylvania State Univ., University Park, PA (United States); Mayers, J. [Rutherford Appleton Lab., Chilton, Didcot (United Kingdom)

    1995-08-01

    We present inelastic neutron scattering measurements of liquid {sup 3}He-{sup 4}He mixtures at 1.5 K and at {sup 3}He concentrations of 0,15,40,70 and 100%. There is little apparent concentration dependence of the {sup 3}He kinetic energy, in disagreement with recent variational calculations for mixtures. The kinetic energy of the {sup 4}He component for the lower concentration mixtures is consistent with theoretical predictions. (orig.).

  8. Magnetization and Spin-Diffusion of Liquid 3He in Aerogel

    OpenAIRE

    Sauls, J. A.; Bunkov, Yu. M.; Collin, E.; Godfrin, H.; Sharma, P

    2004-01-01

    We report theoretical calculations of the normal-state spin diffusion coefficient of 3He in aerogel, including both elastic and inelastic scattering of 3He quasiparticles, and compare these results with experimental data for 3He in 98% porous silica aerogel. This analysis provides a determination of the elastic mean free path within the aerogel. Measurements of the magnetization of the superfluid phase provide a test of the theory of pairbreaking and magnetic response of low-energy excitation...

  9. Observation of Majorana Quasiparticles Surface States in Superfluid ${^3}$He-B by Heat Capacity Measurements

    OpenAIRE

    Bunkov, Yury M.; Gazizulin, Rasul R.

    2016-01-01

    We report about direct measurements of heat capacity of Majorana quasiparticles in superfluid ${^3}$He-B which appear near the surface of the experimental bolometer on the coherence length ${\\xi}$. Two bolometers with different surface-to-volume ratios were used which allows us to have different calibrated contributions from Majorana quasiparticles to the ${^3}$He heat capacity. Estimations of possible impact of ${^3}$He layers adsorbed on the walls of the bolometer have been done.

  10. 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)

  11. {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.)

  12. 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.

  13. Extraterrestrial 3He in marine polymetallic nodules: a potential method for measuring growth rate of nodules

    Institute of Scientific and Technical Information of China (English)

    李延河; 宋鹤彬; 李金城

    2002-01-01

    The comparative measurements of helium isotope compositions between marine polymetallic nodules and their surrounding sediments, their magnetic fractions and bulk from C-C Zone of the East Pacific Basin are reported. The 4He content and 3He/4He ratio of polymetallic nodules and their surrounding sediments are extremely high; the 3He, 4He concentrations and most 3He/4He ratios of magnetic fractions in nodules and sediments are apparently higher than those in bulk. The helium isotope data points of nodules and sediments are all distributed along or closely to the mixing curve of the interplanetary dust particles (IDPs) and the terrigenous sediments in the chart of 3He-3He/4He. In the same sampling site, the 3He/4He ratios of nodules and their surrounding sediments are very similar, and the changes of both ratios are synchronous. It shows that the high 3He/4He ratios in nodules and sediments may all result from IDPs. So, if the flux of extraterrestrial 3He into the nodules and sediments is constant, the growth rate of polymetallic nodules and the sedimentation rate of sediments can be independently calculated according to the concentration of extraterrestrial 3He in nodules and sediments.

  14. Elastic break-up of 156 MeV 6Li projectiles with large asymptotic relative momenta of the fragments

    International Nuclear Information System (INIS)

    The triple differential cross sections for elastic break-up of 156 MeV 6Li projectiles by the reactions 208Pb (6Li, ad) 208Pbg.s., and 12C (6Li, ad) 12Cg.s. have been measured with large asymptotic relative momenta of the outgoing fragments. The data exhibit rather unfamiliar shapes of the energy spectra, often replacing the usual bell-shape distributions by double-peaked structures and varying rapidly with the relative emission angles. The origin of these features has been explored and the cross sections have been analysed on the basis of a diffractive disintegration approach. (orig.)

  15. 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.

  16. 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.

  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. A moving domain wall and order parameter orientation in 3He-B

    International Nuclear Information System (INIS)

    It is shown that movement of domain wall in the earlier considered two-domain structure in superfluid 3He β-phase eliminates the structure double degeneracy. It is suggested to use this fact for one-valued order parameter orientation in 3He-B

  19. First detection of 3He+ in the planetary nebula IC 418

    Science.gov (United States)

    Guzman-Ramirez, L.; Rizzo, J. R.; Zijlstra, A. A.; García-Miró, C.; Morisset, C.; Gray, M. D.

    2016-07-01

    The 3He 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. 3He abundances in PNe can help test models of the chemical evolution of the Galaxy. We present the detection of the 3He+ emission line using the single dish Deep Space Station 63, towards the PN IC 418. We derived a 3He/H abundance in the range 1.74 ± 0.8 × 10-3 to 5.8 ± 1.7 × 10-3, depending on whether part of the line arises in an outer ionized halo. The lower value for 3He/H ratio approaches values predicted by stellar models which include thermohaline mixing, but requires that large amounts of 3He are produced inside low-mass stars which enrich the interstellar medium (ISM). However, this overpredicts the 3He abundance in H II regions, the ISM, and protosolar grains, which is known to be of the order of 10-5. This discrepancy questions our understanding of the evolution of the 3He, from circumstellar environments to the ISM.

  20. Possible Dimensional Crossover to 1D of ^3He Fluid in Nanochannels Observed in Susceptibilities

    Science.gov (United States)

    Matsushita, Taku; Kurebayashi, Katsuya; Shibatsuji, Ryosuke; Hieda, Mitsunori; Wada, Nobuo

    2016-05-01

    Dimensional crossover to the one-dimensional (1D) state from higher dimensions has been studied for dilute ^3He fluid adsorbed in 2.4 nm ^4He-preplated nanochannels, by susceptibility measurements down to 70 mK using 4.29 MHz nuclear magnetic resonance. In nanochannels, since energy states of ^3He motion perpendicular to the channel axis are discrete, a genuine 1D ^3He fluid is expected when the Fermi energy is less than the first excitation Δ _{01} for azimuthal motion. The susceptibilities χ above 0.3 K show the Curie-law susceptibilities independent of the ^3He density, which are characteristic of nondegenerate fluid in higher dimensions. With decreasing the temperature, a significant reduction of χ T was observed from about 0.3 K for all ^3He densities. It is considered to be due to the dimensional crossover below Δ _{01}˜ 0.5 K to the 1D ^3He state in the semi-degenerate regime above the Fermi temperature. In the 1D state at lower temperatures, T-independent χ were observed for ^3He of 0.019 layers below 0.1 K. It suggests that the 1D ^3He fluid enters the quantum degenerate regime.

  1. Towards the observation of the magnetic structure of solid 3He

    International Nuclear Information System (INIS)

    Experiments involving neutron scattering by 3He for which thermalization problems have been solved, along with the development of novel measurement techniques (density, magnetization, temperature) by polarized neutron transmission, crystallization experiments with 3He and 4He: a single crystal of helium have been obtained within a sintered metal in which the pore size is less than a micron are presented

  2. 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.

  3. 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.``

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

    Energy Technology Data Exchange (ETDEWEB)

    Soukeras, V.; Pakou, A.; Sgouros, O. [Department of Physics and HINP, The University of Ioannina, 45110 Ioannina (Greece); Cappuzzello, F.; Bondi, M.; Nicolosi, D. [INFN Laboratory Nazionali del Sud, via S. Sofia 62, 95125, Catania, Italy and Dipartimento di Fisica e Astronomia, Universita di Catania, via S. Sofia 64, 95125, Catania (Italy); Acosta, L.; Marquinez-Duran, G.; Martel, I. [Departamento di Fisica Aplicada, Universidad de Huelva, E-21071, Huelva (Spain); Agodi, C.; Carbone, D.; Cavallaro, M.; Cunsolo, A.; Di Pietro, A.; Fernández-García, J. P.; Figuera, P.; Fisichella, M. [INFN Laboratory Nazionali del Sud, via S. Sofia 62, 95125, Catania (Italy); Alamanos, N. [CEA-Saclay, DAPNIA-SPhN, 91191, Gif-sur-Yvette (France); De Napoli, M. [INFN - Sezione di Catania, via S. Sofia 64, 95125, Catania (Italy); Foti, A. [Dipartimento di Fisica e Astronomia, Universita di Catania, via S. Sofia 64, 95125, Catania, Italy and INFN - Sezione di Catania, via S. Sofia 64, 95125, Catania (Italy); and others

    2015-02-24

    Elastic scattering measurements have been performed for the {sup 6}Li+p system in inverse kinematics at the energies of 16, 20, 25 and 29 MeV. The heavy ejectile was detected by the large acceptance MAGNEX spectrometer at the Laboratori Nazionali del Sud (LNS) in Catania, in the angular range between ∼2{sup 0} and 12{sup 0} in the laboratory system, giving us the possibility to span almost a full angular range in the center of mass system. Results will be presented and discussed for one of the energies.

  5. Reexamining closed-form formulae for inclusive breakup: Application to deuteron and $^6$Li induced reactions

    CERN Document Server

    Lei, Jin

    2015-01-01

    The problem of the calculation of inclusive breakup cross sections in nuclear reactions is reexamined. For that purpose, the post-form theory proposed by Ichimura, Austern and Vincent [Phys. Rev. C32, 431 (1985) is revisited, and an alternative derivation of the non-elastic breakup part of the inclusive breakup is presented, making use of the coupled-channels optical theorem. Using the DWBA version of this model, several applications to deuteron and $^6$Li reactions are presented and compared with available data. The validity of the zero-range approximation of the DWBA formula is also investigated by comparing zero-range with full finite-range calculations.

  6. The scattering of 136 MeV protons from 6Li

    International Nuclear Information System (INIS)

    Differential cross sections have been measured for the elastic scattering of 136 MeV protons from 6Li, and for inelastic scattering to the first two excited states. The optical model fit to the elastic scattering differential cross section gave parameters which were retained for the analysis of the two inelastic transitions. The latter differential cross sections were fairly well fitted in shape, but in both cases there is a discrepancy in absolute magnitude of a factor between 1.5 and 4

  7. The ground state energy of 3He droplet in the LOCV framework

    International Nuclear Information System (INIS)

    The (extended) lowest order constrained variational method was used to calculate the ground state energy of liquid helium 3 (3He) droplets at zero temperature. Different types of density distribution profiles, such as the Gaussian, the Quasi-Gaussian and the Woods-Saxon were used. It was shown that at least, on average, near 20 3He atoms are needed to get the bound state for 3He liquid droplet. Depending on the choice of the density profiles and the atomic radius of 3He, the above estimate can increase to 300. Our calculated ground state energy and the number of atoms in liquid 3He droplet were compared with those of Variational Monte Carlo method, Diffusion Monte Carlo method and Density Functional Theory, for which a reasonable agreement was found.

  8. Burnup of fusion produced tritons and 3He ions in PLT and PDX

    International Nuclear Information System (INIS)

    The d(d,p)t and d(d,n)3He fusion reactions produce 1 MeV tritons and 0.8 MeV 3He ions which can subsequently undergo d(t,n)α and d(3He,p)α fusion reactions. The magnitude of this triton and 3He ion burnup was measured on the PLT and PDX tokamaks by detection of the 14 MeV neutron and 15 MeV proton emission. In discharges with B/sub phi/ greater than or equal to 2 T, the measured 3He burnup agrees well with predictions based on classical theories of ion confinement and slowing down, while the triton burnup was about four times lower than theoretically predicted. In discharges with weaker toroidal fields, the burnup of both ions fell by more than a factor of ten

  9. 6Li detection in metal-poor stars: can 3D model atmospheres solve the second lithium problem?

    CERN Document Server

    Steffen, M; Caffau, E; Bonifacio, P; Ludwig, H -G; Spite, M

    2012-01-01

    The presence of 6Li in the atmospheres of metal-poor halo stars is usually inferred from the detection of a subtle extra depression in the red wing of the 7Li doublet line at 670.8 nm. However, the intrinsic line asymmetry caused by convective flows in the photospheres of cool stars is almost indistinguishable from the asymmetry produced by a weak 6Li blend on a (presumed) symmetric 7Li profile. Previous determinations of the 6Li/ 7Li isotopic ratio based on 1D model atmospheres, ignoring the convection-induced line asymmetry, must therefore be considered as upper limits. By comparing synthetic 1D LTE and 3D non-LTE line profiles of the Li 670.8 nm feature, we quantify the differential effect of the convective line asymmetry on the derived 6Li abundance as a function of effective temperature, gravity, and metallicity. As expected, we find that the asymmetry effect systematically reduces the resulting 6Li/7Li ratios. Depending on the stellar parameters, the 3D-1D offset in 6Li/7Li ranges between -0.005 and -0....

  10. Tritium production in a sphere of 6LiD irradiated by 14-MeV neutrons

    International Nuclear Information System (INIS)

    The specific production of tritium in samples of 6LiH and 7LiH embedded in a 600-mm-diam sphere of 6LiD 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 6LiD 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 6Li(n,α) cross section is well known. The specific production of tritium in 6LiH and 7LiH (embedded samples) and the activation of radiochemical detector foils of 45Sc, 89Y, 90Zr, 169Tm, 191Ir 373, 193Ir 627, 197Au, 235U, and 238U placed at various positions in the 6LiD 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

  11. {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.

  12. Hyperpolarised 3He MRI and 81mKr SPECT in chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    During recent years, magnetic resonance imaging (MRI) using hyperpolarised (HP) 3He gas has emerged as a promising new method for the imaging of lung ventilation. However, systematic comparisons with nuclear medicine techniques have not yet been performed. The aim of this study was to compare ventilation imaging methods in 26 patients with chronic obstructive pulmonary disease (COPD) and nine lung healthy volunteers. HP 3He MRI, 81mKr single-photon emission computed tomography (SPECT), high-resolution computed tomography (HRCT) and pulmonary function tests were performed. The three scans were scored visually as percentage of non-ventilated/diseased lung, and a computer-based objective measure of the ventilated volume in HP 3He MRI and 81mKr SPECT and an emphysema index in HRCT were calculated. We found a good correlation between HP 3He MRI and 81mKr SPECT for both visual defect score (r=0.80, p81mKr 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). HP 3He MRI provides detailed ventilation distribution images and defect scores are comparable on HP 3He MRI and 81mKr SPECT. Additionally, new insights into the regional pulmonary microstructure via the apparent diffusion coefficient measurements are provided by HP 3He MRI. HP 3He MRI is a promising new diagnostic tool for the assessment of ventilation distribution. (orig.)

  13. Electron bubbles and Weyl fermions in chiral superfluid 3He-A

    Science.gov (United States)

    Shevtsov, Oleksii; Sauls, J. A.

    2016-08-01

    Electrons embedded in liquid 3He form mesoscopic bubbles with large radii compared to the interatomic distance between 3He atoms, voids of Nbubble≈200 3He atoms, generating a negative ion with a large effective mass that scatters thermal excitations. Electron bubbles in chiral superfluid 3He-A also provide a local probe of the ground state. We develop a scattering theory of Bogoliubov quasiparticles by negative ions embedded in 3He-A that incorporates the broken symmetries of 3He-A , particularly broken symmetries under time reversal and mirror symmetry in a plane containing the chiral axis l ̂. Multiple scattering by the ion potential, combined with branch conversion scattering by the chiral order parameter, leads to a spectrum of Weyl fermions bound to the ion that support a mass current circulating the electron bubble—a mesoscopic realization of chiral edge currents in superfluid 3He-A films. A consequence is that electron bubbles embedded in 3He-A acquire angular momentum, L ≈-(Nbubble/2 ) ℏ l ̂ , inherited from the chiral ground state. We extend the scattering theory to calculate the forces on a moving electron bubble, both the Stokes drag and a transverse force, FW=e/c v ×BW , defined by an effective magnetic field, BW∝l ̂ , generated by the scattering of thermal quasiparticles off the spectrum of Weyl fermions bound to the moving ion. The transverse force is responsible for the anomalous Hall effect for electron bubbles driven by an electric field reported by the RIKEN group. Our results for the scattering cross section, drag, and transverse forces on moving ions are compared with experiments and shown to provide a quantitative understanding of the temperature dependence of the mobility and anomalous Hall angle for electron bubbles in normal and superfluid 3He-A . We also discuss our results in relation to earlier work on the theory of negative ions in superfluid 3He.

  14. 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...

  15. Measuring the absorption mean cross section in 6Li relative to 235U fission

    International Nuclear Information System (INIS)

    Due to the fact that the neutron absorption cross section in 6Li is used as one of standards for determinaton of neutron-physical characteristics of fast reactors the ratio of mean cross sections for absorption by 6Li (A6) and 235U fission F25 are experimentalli investigated. The measurements have been performed in the KBR-8, KBR-10,BFS/39/1 bfs-44, BFS/45a-1 and BFS-46 critical assemblies which are characterized by various neutron spectra by means of a lithium counter with semiconductor detectors. Ratios A6/F25 for investigated assemblies constituted respectively 0.605+-0.009; 0.604+-0.004; 0.581+-0.009; 0.590+-0.574+-0.005. The values of 235U diffusion mean cross sections obtained on the base of these fata and calculated using the CRAB-1 program (given in brackets) are equal respectively 1.53+-0.005 (1.51) 2.38+-0.08 (2.42); 1.935+-0.060 (1.95); 1.89+-0.08 (1.95); 1.780+-0.11 (1.69); 1.90+-0.06 (1.89)

  16. Detection efficiency simulation and measurement of 6LiI/natLiI scintillation detector

    International Nuclear Information System (INIS)

    Background: Being of very high detection efficiency and small size, Lithium iodide (LiI) scintillator detector is used extensively in neutron measurement and environmental monitoring. Purpose: Using thermal reactor, neutron detectors will be tested and calibrated. And a new neutron detector device will be designed and studied. Methods: The relationship between the size and detection efficiency of the thermal neutron detector 6LiI/natLil was studied using Monte Carlo code GEANT4 and MCNP5 package, and the thermal neutron efficiency of detector was calibrated by reactor neutrons. Results: The theoretical simulation shows that the thermal neutron detection efficiency of detector of 10-mm thickness is relatively high, the enriched 6Lil is up to 98% and the nature natLiI 65%. The thermal neutron efficiency of detector is calibrated by reactor thermal neutrons. Considering the neutron scattering by the lead brick, high density polythene and environment neutron contribution, the detection efficiency of 6LiI detector is about 90% and natLiI detector 70%. Conclusion: The detector efficiency can reach the efficiency value of theoretical calculations. (authors)

  17. Exploring an ultracold Fermi-Fermi mixture: interspecies Feshbach resonances of ^6Li-^40K

    Science.gov (United States)

    Schreck, Florian

    2008-03-01

    We report on the observation of interspecies Feshbach resonances in an ultracold mixture of two fermionic species, ^6Li and ^40K. Interpretation of the data unambiguously assigns molecular bound states to the various resonances and fully characterizes the ground-state scattering properties in any combination of spin states. Using this knowledge we hope to be able to produce ^6Li-^40K molecules, cool them to quantum degeneracy, and study their BEC-BCS crossover. In collaboration with: F. Schreck, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria; E. Wille, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria and Institut fuer Experimentalphysik und Forschungszentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck, Austria; F.M. Spiegelhalder, G. Kerner, D. Naik, A. Trenkwalder, G. Hendl, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria; R. Grimm, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria and Institut fuer Experimentalphysik und Forschungszentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck, Austria; T.G. Tiecke, J.T.M. Walraven,Van der Waals-Zeeman Institute of the University of Amsterdam, 1018 XE, The Netherlands; S.J.J.M.F. Kokkelmans, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; E. Tiesinga, P.S. Julienne, Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, Maryland 20899-8423, USA

  18. 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

  19. Gas cells for 3He hyperpolarized via spin-exchange optical pumping

    Science.gov (United States)

    Kim, W.; Stepanyan, S. S.; Kim, A.; Tan, J. A.; Woo, S.

    2016-01-01

    We present a device for the production of hyperpolarized 3He, which is widely used in spinrelated nuclear physics research. Spin-exchange optical pumping (SEOP) is employed to polarize 3He enclosed in a circular borosilicate glass cell suitable not only for the production of polarized gas but also for its storage. The portable glass cell can, thus, be transported to any other research facility. The glass cell can be refilled several times. Special attention is given to the preparation and the filling of the cell to minimize the impurities on its walls and in the gas. We employ glass tubes with shorter lengths and larger diameters in the gas-filling system to achieve the improvement in the air flow necessary to obtain purer polarized 3He samples. The cell is prepared, and after it has been filled with rubidium (Rb) and 3He-N2 mixture, it is sealed under high vacuum conditions. The cell containing the mixture is exposed to circularly-polarized laser light with a wavelength of 795 nm at temperatures of 180 - 220 °C for SEOP. The polarization of 3He is measured via nuclear magnetic resonance (NMR). We obtained 40% polarized 3He in less than 15 hours and 50% in about 25 hours. The longitudinal relaxation time T 1 of the polarized 3He we measured was about 58 hours.

  20. 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...

  1. 3He(d,p)4He reaction calculation with three-body Faddeev equations

    International Nuclear Information System (INIS)

    In order to investigate the 3He-n-p system as a three-body problem, we have formulated 3He-n and 3H-p effective potentials using both a microscopic treatment and a phenomenological approach. In the microscopic treatment, potentials are generated by means of the resonating group method (RGM) based on the Minnesota nucleon-nucleon potential. These potentials are converted into separable form by means of the microscopic Pauli correct (MPC) method. The MPC potentials are properly formulated to avoid Pauli forbidden states. The phenomenological potentials are obtained by modifying parameters of the EST approximation to the Paris nucleon-nucleon potential, such that they fit the low-energy 3He-n, 3H-p, and 3He-p phase shifts. Therefore, they describe the 3He-n differential cross section, the polarization observables, and the energy levels of 4He. The 3He-n-p Faddeev equations are solved numerically. We reproduce correctly the ground state and the first excited state of 5Li. Furthermore, the Paris-type potential is used to investigate the 3He(d,p)4He reaction at a deuteron bombarding energy of 270 MeV, where the system is treated as a three-body problem. Results for the polarized and unpolarized differential cross sections demonstrate convergence of the Born series. (orig.)

  2. Study on (n3, He) fusion reactions cross sections using optical model

    International Nuclear Information System (INIS)

    Non-elastic cross-sections have been calculated by using optical model for (n3, He) reactions at 22.5 MeV energy. The empirical formula including optical model non-elastic effects by fitting two parameters for the (n3, He) reaction cross-sections have been suggested. Reaction Q-values depending on the asymmetry term effect for the (n3, He) reaction have been investigated. The obtained cross-section formula with new coefficients has been compared with the experimental data and discussed. It has seen that the fit of formula in this paper is in good agreement with the experimental data

  3. New data and evaluation of sup 3 He-induced nuclear reactions on Cu

    CERN Document Server

    Tarkanyi, F; Takács, S; Al-Abyad, M; Mustafa, M G; Shubin, Y; Zhuang, Y

    2002-01-01

    Excitation functions of sup n sup a sup t Cu( sup 3 He, x) sup 6 sup 6 Ga, sup n sup a sup t Cu( sup 3 He, x) sup 6 sup 7 Ga, sup n sup a sup t Cu( sup 3 He, x) sup 6 sup 3 Zn and sup n sup a sup t Cu( sup 3 He, x) sup 6 sup 5 Zn nuclear reactions were measured up to 36 MeV using stacked foil irradiation arrangement and activation technique. The results were compared with compiled literature data. The status of the experimental database was investigated with the goal to produce recommended values for different applications. The application of the deduced data in the field of beam monitoring and thin layer activation is discussed.

  4. The ion optics of a miniature 3He/4He mass spectrometer of high resolution

    International Nuclear Information System (INIS)

    To measure the isotopic abundance ratio of 3He and 4He in samples by mass spectrometers is an important detection mean for helium isotope geochemistry research. A symmetrically arranged tandem 3He/4He mass spectrometer is described in the paper. The front stage, used to analyse 3He (including HD and H3) and 4He, is a homogeneous analysing magnet with a bending angle of 90 deg and a bending radius of 6 cm. The end stage, used to analyse 3He, HD and H3, is a non-homogeneous analysing magnet with a bending angle of 180 deg, a bending radius of 15 cm and a magnetic field gradient of 0.75. Because of the use of the non-zero second order coefficient β and curved entrance face of the later magnet for eliminating second order aberrations, the resolving power of the system is notably improved, and theoretically reaches about 3800

  5. 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.

  6. Measurements of the structure and nucleation of vorticity in the (3)He superfluids. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Parts, U.

    1995-10-01

    This thesis reports experiments on rotating superfluid 3He, which were performed in the Low Temperature Laboratory during the period 1991-94, and which are published in a series of original publications. Rotation is particularly useful for creating various types of topological objecs, e.g. quantized vortex lines, in large quantities for systematic investigation. The author`s method to study them is the nuclear magnetic resonance (NMR) technique, which has been an important experimental tool in various fields of physics for about fifty years. In the case of superfluid 3He, NMR provides direct information on the spatial distribution of the order parameter field. Both superfluid phases of 3He, the A- and the B-phase, have been under investigation in this thesis work. In 3He-B the main concern has been the nucleation of singular vortices. This process involves an energy barrier, similar to a first order phase transition.

  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....... The three scans were scored visually as percentage of non-ventilated/diseased lung, and a computer-based objective measure of the ventilated volume in HP 3He MRI and 81mKr SPECT and an emphysema index in HRCT were calculated. RESULTS: We found a good correlation between HP 3He MRI and 81mKr SPECT for both...... visual defect score (r=0.80, pKr SPECT (the score on HP 3He MRI...

  8. Discovery of superfluid 3He phases wins 1996 nobel prize in physics

    International Nuclear Information System (INIS)

    The 1996 Nobel prize in physics was awarded to David M. Lee, Douglas D. Osheroff and Robert C. Richardson for their discovery of superfluidity in 3He in 1971. A short account of the discovery and its importance is given

  9. 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.

  10. 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.

  11. High-efficiency microstructured semiconductor neutron detectors for direct 3He replacement

    International Nuclear Information System (INIS)

    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 3He 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 3He detector of the same dimensions. The Generation 1 MSND-based 3Helium-Replacement (HeRep Mk I) device contained sixty-four 1-cm2 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-cm2 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 3He 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 3He counter and the HeRep Mk II were each placed 1 m from a 54-ng 252Cf source and tested for efficiency. The 3He 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 3He gas counter while inside of the moderator. Outside of moderator, the 3He 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 3He neutron detector

  12. A compact SEOP 3He neutron spin filter with AFP NMR

    Science.gov (United States)

    Ino, Takashi; Arimoto, Yasushi; Shimizu, Hirohiko M.; Sakaguchi, Yoshifumi; Sakai, Kenji; Kira, Hiroshi; Shinohara, Takenao; Oku, Takayuki; Suzuki, Jun-ichi; Kakurai, Kazuhisa; Chang, Lieh-Jeng

    2012-02-01

    We developed AFP NMR in an aluminum container for polarized noble gas nuclei. The radio frequency magnetic field inside the aluminum container was designed from computer simulations. The polarization loss by the AFP spin flip of 3He was measured to be as low as 3.8×10-4. With this technique, a compact in-situ polarizing 3He neutron spin filter with AFP NMR is demonstrated.

  13. {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.

  14. Hyperpolarized 3He magnetic resonance imaging: Preliminary evaluation of phenotyping potential in chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    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 (3He) magnetic resonance imaging (MRI) functional and structural measurements and to explore the potential role for 3He 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, 1H MRI and hyperpolarized 3He MRI at 3.0 T. 3He ventilation defect percent (VDP) was generated from 3He static ventilation images and 1H thoracic images and the 3He 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 3He 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 3He MRI to categorize or phenotype COPD ex-smokers, providing good evidence of feasibility for larger prospective studies.

  15. Improved Technique for Measurement of Regional Fractional Ventilation by Hyperpolarized 3He MRI

    OpenAIRE

    Emami, Kiarash; Kadlecek, Stephen J.; Woodburn, John M.; Zhu, Jianliang; Yu, Jiangsheng; Vahdat, Vahid; Pickup, Stephen; Ishii, Masaru; Rizi, Rahim R.

    2010-01-01

    Quantitative measurement of regional lung ventilation is of great significance in assessment of lung function in many obstructive and restrictive pulmonary diseases. A new technique for regional measurement of fractional ventilation using hyperpolarized 3He MRI is proposed, addressing the shortcomings of an earlier approach that limited its use to small animals. The new approach allows for the acquisition of similar quantitative maps over a shortened period and requires substantially less 3He...

  16. 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.

  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. 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.

  19. 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.

  20. Study of reaction products of d + 6Li at 0,18 MeV

    International Nuclear Information System (INIS)

    The study of continuous spectra of low energy particles, and more particularly of their shape and intensity allows a better understanding and knowledge of the structure of nuclei as they interact when encountering. As previous studies performed in Saclay had been interpreted by introducing the new notions of nuclear molecule or activated complex followed by a dissymmetric breaking, and in order to better understand the formation of these molecules, this research thesis reports the study of the d + 6Li reaction at 0,18 MeV. After a description of the experimental installation and of the processing of nuclear emulsions, the author presents and discusses the obtained results and calculations resulting from the fact that the different particles cannot be discriminated in the continuum. Theoretical results for the continuous spectrum are compared with experimental results, and the author reports angular distributions of alpha particles and p0 and p1 protons

  1. Possibilities for breakeven and ignition of D-3He fusion fuel in a near term tokamak

    International Nuclear Information System (INIS)

    The recent realization that the moon contains a large amount of the isotope 3He has rekindled interest in the D-3He fuel cycle. In this study we consider the feasibility of investigating D-3He reactor plasma conditions in a tokamak of the NET/INTOR class. We have found that, depending on the energy confinement scaling law, energy breakeven may be achieved without significant modification to the NET design. The best results are for the more optimistic ASDEX H-mode scaling law. Kaye-Goldston scaling with a modest improvement due to the H-mode is more pessimistic and makes achieving breakeven more difficult. Significant improvement in Q (ratio of the fusion power to the injected power), or the ignition margin, can be achieved by taking advantage of the much reduced neutron production of the D-3He fuel cycle. Removal of the tritium producing blanket and replacing the inboard neutron shield by a thinner shield optimized for the neutron spectrum in D-3He allows the plasma to be increased without changing the magnetic field at the toroidal field magnet. This allows the plasma to achieve higher beta and Q values up to about 3. The implications of D-3He operation for fast ion loss, neutron shielding, heat loads on the first wall and divertor, plasma refuelling, changes to the poloidal field coil system, and pumping of the helium from the vacuum chamber are considered in the report. (orig.)

  2. First doubly polarised photoproduction on 3He at the photon beam of MAMI

    International Nuclear Information System (INIS)

    A first experiment with a polarised 3He 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 3He 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 3He. 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 3He target. The data were taken using the 4π 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 3He 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 3He compared with several theoretical models will also be presented. (orig.)

  3. Polarized 3He+2 ions in the Alternate Gradient Synchrotron to RHIC transfer line

    Science.gov (United States)

    Tsoupas, N.; Huang, H.; Méot, F.; Ptitsyn, V.; Roser, T.; Trbojevic, D.

    2016-09-01

    The proposed electron-hadron collider (eRHIC) to be built at Brookhaven National Laboratory (BNL) will allow the collisions of 20 GeV polarized electrons with 250 GeV polarized protons, or 100 GeV /n polarized 3He+2 ions, or other unpolarized ion species. The large value of the anomalous magnetic moment of the 3He nucleus GHe=(g -2 )/2 =-4.184 (where g is the g -factor of the 3He nuclear spin) combined with the peculiar layout of the transfer line which transports the beam bunches from the Alternate Gradient Synchrotron (AGS) to the Relativistic Heavy Ion Collider (RHIC) makes the transfer and injection of polarized 3He ions from AGS to RHIC (AtR) a special case as we explain in the paper. Specifically in this paper we calculate the stable spin direction of a polarized 3He beam at the exit of the AtR line which is also the injection point of RHIC, and we discuss a simple modifications of the AtR beam-transfer-line, to perfectly match the stable spin direction of the injected polarized 3He beam to that of the circulating beam, at the injection point of RHIC.

  4. 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 (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.

  5. Asymptotic and near-target direct breakup of 6Li and 7Li

    Science.gov (United States)

    Kalkal, Sunil; Simpson, E. C.; Luong, D. H.; Cook, K. J.; Dasgupta, M.; Hinde, D. J.; Carter, I. P.; Jeung, D. Y.; Mohanto, G.; Palshetkar, C. S.; Prasad, E.; Rafferty, D. C.; Simenel, C.; Vo-Phuoc, K.; Williams, E.; Gasques, L. R.; Gomes, P. R. S.; Linares, R.

    2016-04-01

    Background: Li,76 and 9Be are weakly bound against breakup into their cluster constituents. Breakup location is important for determining the role of breakup in above-barrier complete fusion suppression. Recent works have pointed out that experimental observables can be used to separate near-target and asymptotic breakup. Purpose: Our purpose is to distinguish near-target and asymptotic direct breakup of Li,76 in reactions with nuclei in different mass regions. Method: Charged particle coincidence measurements are carried out with pulsed Li,76 beams on 58Ni and 64Zn targets at sub-barrier energies and compared with previous measurements using 208Pb and 209Bi targets. A detector array providing a large angular coverage is used, along with time-of-flight information to give definitive particle identification of the direct breakup fragments. Results: In interactions of 6Li with 58Ni and 64Zn, direct breakup occurs only asymptotically far away from the target. However, in interactions with 208Pb and 209Bi, near-target breakup occurs in addition to asymptotic breakup. Direct breakup of 7Li into α -t is not observed in interactions with 58Ni and 64Zn. However, near-target dominated direct breakup was observed in measurements with 208Pb and 209Bi. A modified version of the Monte Carlo classical trajectory model code platypus, which explicitly takes into account lifetimes associated with unbound states, is used to simulate sub-barrier breakup reactions. Conclusions: Near-target breakup in interactions with Li,76 is an important mechanism only for the heavy targets 208Pb and 209Bi. There is insignificant near-target direct breakup of 6Li and no direct breakup of 7Li in reactions with 58Ni and 64Zn. Therefore, direct breakup is unlikely to suppress the above-barrier fusion cross section in reactions of Li,76 with 58Ni and 64Zn nuclei.

  6. 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)

  7. 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

  8. 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

  9. Development of a 3He/Xe gas scintillation counter to measure the 3He(n,p)T cross section in the intermediate energy range

    International Nuclear Information System (INIS)

    A 3He/Xe gas scintillation counter has been developed for measuring the neutron energy range from thermal to 3 MeV. Great effort was concentrated on improving the detector design to optimize light production and collection to improve the energy resolution which is primarily controlled by photon statistics. The detectors were tested using a 238Pu alpha-particle source, a thermal neutron beam from the NBS reactor, and the white-neutron spectrum from the NBS linac. The detector measures an energy resolution of 17 % (FWHM) for the 3He(n,p)T reaction at 2.0 MeV which is sufficient for cross section measurement. (author)

  10. Development of a 3He/Xe gas scintillation counter to measure the 3He(n,p)T cross section in the intermediate energy range

    International Nuclear Information System (INIS)

    A 3He/Xe gas scintillation counter has been developed for measuring the neutron energy range from thermal to 3 MeV. Great effort was concentrated on improving the detector design to optimize light production and collection to improve the energy resolution which is primarily controlled by photon statistics. The detectors were tested using a 238Pu alpha-particle source, a thermal neutron beam from the NBS reactor, and the white-neutron spectrum from the NBS linac. The detector measures an energy resolution of 17% (FWHM) for the 3He(n,p)T reaction at 2.0 MeV which is sufficient for cross section measurement. 12 refs., 8 figs

  11. Integrated readout of organic scintillator and ZnS:Ag/6LiF for segmented antineutrino detectors.

    Energy Technology Data Exchange (ETDEWEB)

    Kiff, Scott D.; Reyna, David; Monahan, James; Bowden, Nathaniel S.

    2010-11-01

    Antineutrino detection using inverse beta decay conversion has demonstrated the capability to measure nuclear reactor power and fissile material content for nuclear safeguards. Current efforts focus on aboveground deployment scenarios, for which highly efficient capture and identification of neutrons is needed to measure the anticipated antineutrino event rates in an elevated background environment. In this submission, we report on initial characterization of a new scintillation-based segmented design that uses layers of ZnS:Ag/{sup 6}LiF and an integrated readout technique to capture and identify neutrons created in the inverse beta decay reaction. Laboratory studies with multiple organic scintillator and ZnS:Ag/{sup 6}LiF configurations reliably identify {sup 6}Li neutron captures in 60 cm-long segments using pulse shape discrimination.

  12. Integrated readout of organic scintillator and ZnS:Ag/6LiF for segmented antineutrino detectors.

    Energy Technology Data Exchange (ETDEWEB)

    Kiff, Scott D.; Reyna, David; Monahan, James (Drexel University, Philadelphia, PA); Bowden, Nathaniel S. (Lawrence Livermore National Laboratory, Livermore, CA)

    2010-10-01

    Antineutrino detection using inverse beta decay conversion has demonstrated the capability to measure nuclear reactor power and fissile material content for nuclear safeguards. Current efforts focus on aboveground deployment scenarios, for which highly efficient capture and identification of neutrons is needed to measure the anticipated antineutrino event rates in an elevated background environment. In this submission, we report on initial characterization of a new scintillation-based segmented design that uses layers of ZnS:Ag/{sup 6}LiF and an integrated readout technique to capture and identify neutrons created in the inverse beta decay reaction. Laboratory studies with multiple organic scintillator and ZnS:Ag/{sup 6}LiF configurations reliably identify {sup 6}Li neutron captures in 60 cm-long segments using pulse shape discrimination.

  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. Investigations of 6LiIn1-xGaxSe2 semi-insulating crystals for neutron detection

    Science.gov (United States)

    Wiggins, Brenden; Bell, Joseph; Burger, Arnold; Stassun, Keivan; Stowe, Ashley C.

    2015-08-01

    Neutron detectors are used for illicit material detection, neutron radiography, stellar investigations of chemical content including biological compounds in planetary terrain and to monitor nuclear power plant fuel products and radioactive waste. Li-containing chalcogenide materials are promising alternative thermal neutron detection materials due to the incorporation of the 6Li isotope at high density. 6LiInSe2 is limited in its effective thermal neutron efficiency by 115In neutron capture which results in gamma decay rather than charge creation. This study includes investigations of mixed crystalline material 6LiIn1-xGaxSe2 where the indium concentration is reduced by Ga substitution. The optical properties have been tuned by gallium substitution and radiation response has been observed.

  15. Double-folding analysis of the 6Li + 58Ni reaction using the ab initio density distribution

    International Nuclear Information System (INIS)

    The elastic scattering angular distributions of the 6 Li + 58 Ni reaction are reanalyzed by using the double-folding model (DFM) within the framework of the optical model (OM) at energies near the Coulomb barrier, ELab = 9.9, 11.2, 12.1, 13.0 and 14.0 MeV. With this goal, for the first time, the no-core full configuration (NCFC) density distribution (DD) of the 6 Li nucleus is used in order to obtain the real potentials. Also, in order to see the validity of NCFC DD, another density distribution (Gaussian shape) of the 6 Li nucleus is used to obtain the real potentials in DF calculations. The results with NCFC DD are compared with Gaussian shape (GS) DD as well as the experimental data. It has been seen that the NCFC DD results are in agreement with the experimental data, giving better results than GS DD. (orig.)

  16. 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.

  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

    CERN Document Server

    Rinaldi, Matteo

    2014-01-01

    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 tilde-H 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 tilde-H, 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 DVC...

  19. 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.)

  20. 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.

  1. Multi-Spacecraft Observations of Recurrent 3He-Rich Solar Energetic Particles

    CERN Document Server

    Bucik, R; Mall, U; Korth, A; Mason, G M; Gomez-Herrero, R

    2014-01-01

    We study the origin of 3He-rich solar energetic particles (<1 MeV/nucleon) that are observed consecutively on STEREO-B, ACE, and STEREO-A spacecraft when they are separated in heliolongitude by more than 90{\\deg}. The 3He-rich period on STEREO-B and STEREO-A commences on 2011 July 1 and 2011 July 16, respectively. The ACE 3He-rich period consists of two sub-events starting on 2011 July 7 and 2011 July 9. We associate the STEREO-B July 1 and ACE July 7 3He-rich events with the same sizeable active region producing X-ray flares accompanied by prompt electron events, when it was near the west solar limb as seen from the respective spacecraft. The ACE July 9 and STEREO-A July 16 events were dispersionless with enormous 3He enrichment, lacking solar energetic electrons and occurring in corotating interaction regions. We associate these events with a small, recently emerged active region near the border of a low-latitude coronal hole that produced numerous jet-like emissions temporally correlated with type III r...

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

    Directory of Open Access Journals (Sweden)

    Sulkosky Vincent A.

    2016-01-01

    Full Text Available 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 He→3(e→ ,e′d${}^3\\overrightarrow {He} (\\vec e,e'd$ and He→3(e→,e′p${}^3\\overrightarrow {He} (\\vec e,e'p$ 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/c2 and 0.35 (GeV/c2 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.

  3. The development of 3He neutron detectors for applications in high level gamma-ray backgrounds

    International Nuclear Information System (INIS)

    To measure high-level-activity scrap and waste, it is necessary to use neutron detectors that are insensitive to the high gamma-ray background. We have developed a combination of 3He tubes and custom preamplifiers to provide the high efficiency associated with 3He detectors with good gamma-ray rejection. We have preamplifiers with short time constants in the signal processing to help separate the neutron signals from the slower risetime gamma signals. We have compared AMPTEK (A-111) preamplifiers with Precision Data Technology (PDT 110A) preamplifiers with experimental tests for gamma rejection and radiation damage. Hot cell radiation tests using a 4.5 Ci radium source were performed using 10B and 3He detectors to evaluate relative efficiency and the ability to separate neutrons and gamma rays. The AMPTEK A-111 and PDT-110A amplifiers were exposed to gamma doses between ∼0.1 R/h and 1500 R/h to observe where the gamma pileup would interfere with the neutron counting. The conclusion is that both amplifiers can operate in gamma fields up to ∼500 R/h with modest loss of neutron efficiency. This is valid for the case of only one 3He tube (30-cm active length) connected to a single amplifier. If an amplifier services multiple tubes or longer tubes, the gamma rejection will get worse. Studies are in progress to determine the lifetime of the amplifiers and 3He tubes in the high-radiation fields

  4. 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.

  5. Simultaneous measurement of pulmonary partial pressure of oxygen and apparent diffusion coefficient by hyperpolarized 3He MRI

    OpenAIRE

    Yu, Jiangsheng; Law, Michelle; Kadlecek, Stephen; Emami, Kiarash; Ishii, Masaru; Stephen, Michael; Woodburn, John M.; Vahdat, Vahid; Rizi, Rahim R.

    2009-01-01

    Hyperpolarized 3He (HP 3He) MRI shows promise to assess structural and functional pulmonary parameters in a sensitive, regional and non-invasive way. Structural HP 3He MRI has applied the apparent diffusion coefficient (ADC) for the detection of disease-induced lung microstructure changes at the alveolar level, and HP 3He pulmonary partial pressure of oxygen (pO2) imaging measures the oxygen transfer efficiency between the lung and blood stream. Although both parameters are affected in chroni...

  6. 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%.

  7. Longitudinal assessment of treatment effects on pulmonary ventilation using 1H/3He MRI multivariate templates

    Science.gov (United States)

    Tustison, Nicholas J.; Contrella, Benjamin; Altes, Talissa A.; Avants, Brian B.; de Lange, Eduard E.; Mugler, John P.

    2013-03-01

    The utitlity of pulmonary functional imaging techniques, such as hyperpolarized 3He MRI, has encouraged their inclusion in research studies for longitudinal assessment of disease progression and the study of treatment effects. We present methodology for performing voxelwise statistical analysis of ventilation maps derived from hyper­ polarized 3He MRI which incorporates multivariate template construction using simultaneous acquisition of IH and 3He images. Additional processing steps include intensity normalization, bias correction, 4-D longitudinal segmentation, and generation of expected ventilation maps prior to voxelwise regression analysis. Analysis is demonstrated on a cohort of eight individuals with diagnosed cystic fibrosis (CF) undergoing treatment imaged five times every two weeks with a prescribed treatment schedule.

  8. A Short History of the Theory and Experimental Discovery of Superfluidity in 3He

    Science.gov (United States)

    Brinkman, W. F.

    I discuss the development of the theory and experiments on superfluid 3He. After the discovery of superfluidity in 3He by Osheroff, Richardson and Lee, Phil Anderson quickly recruited Doug Osheroff to come to Bell Labs and set up a dilution fridge to continue his experiments. One of the mysteries at that time was how the high-temperature A-phase, which has a gapless excitation spectrum, could be stabilized relative to the fully gapped, lower temperature B-phase. I explain how Phil Anderson and I developed the spin fluctuation theory of the A-phase of superfluid 3He which accounted for its stability, leading to the Anderson-Brinkman-Morel (ABM) theory of the superfluid A-phase...

  9. Experimental study of the 56Ni(3He,d)57Cu reaction in inverse kinematics

    International Nuclear Information System (INIS)

    Measurements of (3He,d) reactions can provide information on the proton widths of states that play a role in astrophysically important (p,γ) reactions. We report on the first study of the (3He,d) reaction in inverse kinematics with a 56Ni (T1/2=6.1 d) ion beam. The Q-value resolution of ∼ keV achieved in this experiment was sufficient to separate the transitions populating the ground state and the 1/2--5/2- doublet at Ex∼1.1 MeV in 57Cu. Prospects for similar (3He,d) experiments with improved energy resolution are also discussed.

  10. The Effect Of Neutron Attenuation On Power Deposition In Nuclear Pumped 3He-Lasers

    Science.gov (United States)

    Çetin, Füsun

    2007-04-01

    Nuclear-pumped lasers (NPLs) are driven by the products of nuclear reactions and directly convert the nuclear energy to directed optical energy. Pumping gas lasers by nuclear reaction products has the advantage of depositing large energies per reaction. The need for high laser power output implies high operating pressure. In the case of volumetric excitation by 3He(n, p)3H reactions, however, operation at high pressure (more than a few atm) causes excessive neutron attenuation in the 3He gas. This fact adversely effects on energy deposition and, hence, laser output power and beam quality. Here, spatial and temporal variations of neutron flux inside a closed 3He -filled cylindrical laser tube have been numerically calculated for various tube radii and operating pressures by using a previously reported dynamic model for energy deposition. Calculations are made by using ITU TRIGA Mark II Reactor as the neutron source. The effects of neutron attenuation on power deposition are examined.

  11. Study of 68Zn, 70Zn and 74Ge using the (d,3He) reaction

    International Nuclear Information System (INIS)

    The 69Ga, 71Ga(d,3He)68Zn, 70Zn and 75As(d,3He)74Ge reactions have been studied at 26MeV with an overall resolution of 18-20keV using a split pole magnetic spectrometer. Spectroscopic factors have been extracted for 16 levels in 68Zn, 14 levels in 70Zn and 24 levels in 74Ge. The ratio R=sigma(02+)/sigma(0+g.s.) shows a singularity at N=40. The small value of R for 74Ge is consistent with a previously proposed description of the structure of the states involved which is based on a simple mixing of psub(3/2) and fsub(5/2) proton configurations. The results for the Ga(d,3He)Zn reactions are compared to a recent shell model calculation

  12. 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.

  13. Binding energy of one [sup 4]He impurity in liquid [sup 3]He

    Energy Technology Data Exchange (ETDEWEB)

    Boronat, J. (Universitat Politecnica de Catalunya, Barcelona (Spain)); Saavedra, F.A. de; Buendia, E. (Universidad de Granola (Spain)); Polls, A. (Universitat de Barcelona (Spain))

    1994-02-01

    A variational microscopic calculation of the binding energy of a [sup 4]He impurity ([mu][sub I]) in homogeneous liquid [sup 3]He at zero temperature is presented. Starting on an extended Jastrow-Slater wave function including three-body correlations, the expression for [mu][sub I] is derived and the appropriated FHNC formalism for this problem is reviewed. In the framework of the Average Correlation Approximation (ACA), it is proved that it is possible to obtain the chemical potential of the impurity only from liquid [sup 3]He magnitudes with a good accuracy. The results are consistent with both a recent experimental determination of [mu][sub I] at zero pressure and the non-solubility of [sup 4]He in [sup 3]He. However, numerical uncertainties preclude a firm conclusion about the latter property.

  14. Double-Cell Geometry for 129Xe/3He Co-Magnetometry

    Science.gov (United States)

    Ohtomo, Yuichi; Ichikawa, Yuichi; Sato, Tomoya; Sakamoto, Yu; Kojima, Shuichiro; Suzuki, Takahiro; Shirai, Hazuki; Chikamori, Masatoshi; Hikota, Eri; Miyatake, Hirokazu; Nanao, Tsubasa; Suzuki, Kunifumi; Tsuchiya, Masato; Inoue, Takeshi; Furukawa, Takeshi; Yoshimi, Akihiro; Bidinosti, Christopher P.; Ino, Takashi; Ueno, Hideki; Matsuo, Yukari; Fukuyama, Takeshi; Asahi, Koichiro

    Comagnetometers play a key role in EDM experiments. They allow one to quantify, and subsequently correct for, any long-term drifts of the external magnetic field. In order to improve the performance of the 3He comagnetometer for our 129Xe EDM measurements, we have decided to incorporate a double-cell geometry which enables us to suppress a frequency shift due to contact interaction with polarized Rb atoms. In this study, the production and relaxation of 3He spin polarization in the double cell were studied. As a result, the followings were achieved: a polarization of 1.04(8)%, a longitudinal spin relaxation time of 10.1(5) h, and a transverse relaxation time of 2,340 s. With these improvements, concurrent operation of the 129Xe and 3He masers has been realized, and EDM measurement will be started in near future using a cell designed based on the results of this study.

  15. 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.

  16. 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...

  17. Bi-layer ^3He: a simple two dimensional heavy fermion system with quantum criticality

    Science.gov (United States)

    Saunders, John

    2008-03-01

    Two dimensional helium films provide simple model systems for the investigation of quantum phase transitions in two dimensions. Monolayer ^3He absorbed on graphite, with various pre-platings, behaves as a two dimensional Mott-Hubbard system, complete with a density driven ``metal-insulator'' transition [1, 2] into what appears to be a gapless spin-liquid. In two dimensions the corrections to the temperature dependence of the fluid heat capacity, beyond the term linear in T, are anomalous and attributed to quasi-1D scattering [3]. On the other hand, bi-layer ^3He films adsorbed on the surface of graphite show evidence of two-band heavy-fermion behavior and quantum criticality [4, 5]. The relevant control parameter is the total density of the ^3He film. The ^3He bilayer system can be driven toward a quantum critical point (QCP) at which the effective mass appears to diverge, the effective inter-band hybridization vanishes, and a local moment state appears. A theoretical model in terms of a ``Kondo breakdown selective Mott transition'' has recently been suggested [6]. * In collaboration with: A Casey, M Neumann, J Nyeki, B Cowan. [1] Evidence for a Mott-Hubbard Transition in a Two-Dimensional ^3He Fluid Monolayer, A. Casey, H. Patel, J. Ny'eki, B. P. Cowan, and J. Saunders Phys. Rev. Lett. 90, 115301 (2003) [2] D Tsuji et al. J. Low Temp. Phys. 134, 31 (2004) [3] A V Chubukov et al. Phys. Rev. B71, 205112 (2005) [4] Bilayer ^3He; a simple two dimensional heavy fermion system with quantum criticality, Michael Neumann, Jan Nyeki, Brian Cowan, John Saunders. Science 317, 1356 (2007) [5] Heavy fermions in the original Fermi liquid. Christopher A Hooley and Andrew P Mackenzie. Science 317, 1332 (2007) [6] C Pepin, Phys. Rev. Lett. 98, 206401 (2007) and A Benlagra and C Pepin, arXiv: 0709.0354

  18. 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.

  19. 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.)

  20. Multi-elemental characterization of organic liquid samples by use of a 13 MeV 6Li3+ beam

    International Nuclear Information System (INIS)

    Evaporated amniotic fluid (AF) targets have been bombarded with a 13 MeV 6Li3+ beam. Forward angle data have served to identify the 1H(6Li,1H)6Li reaction as an alternative for hydrogen characterization of such organic samples. Detected 6Li 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.

  1. T sub 20 in the inclusive breakup of 4. 5 GeV polarized sup 6 Li

    Energy Technology Data Exchange (ETDEWEB)

    Punjabi, V. (Norfolk State University, Norfolk, Virginia 23504 (United States)); Perdrisat, C.F.; Cheung, E. (The College of William and Mary, Williamsburg, Virginia 23185 (United States)); Yonnet, J.; Boivin, M.; Tomasi-Gustafsson, E. (Laboratoire National Saturne, Centre d' Etudes Nucleaires de Saclay, F-91191 Gif-sur-Yvette (France)); Siebert, R.; Frascaria, R.; Warde, E. (Institut de Physique Nucleaire, Universite Paris 13, Orsay (France)); Belostotsky, S.; Miklucho, O.; Sulimov, V. (Leningrad Institute for Nuclear Physics, Gatchina (Russia)); Abegg, R. (TRIUMF, Vancouver, British Columbia, Canada V6T 1W5 and University of Alberta, Edmonton, T6G 2J1 (Canada)); Lehman, D.R. (The George Washington University, Washington, D.C. 20052 (United States))

    1992-09-01

    The analyzing power {ital T}{sub 20} in the inclusive {sup 1}H({sup 6}Li,{ital d} or {alpha} or {ital t}){ital X} reaction with 4.5 GeV tensor polarized {sup 6}Li nuclei has been measured at an angle of 0.8{degree}. The kinematics chosen favor the detection of spectator fragments; in the impulse approximation the laboratory momentum of such a fragment is then the Lorentz boosted internal momentum. Nonzero {ital T}{sub 20} values have been observed, in agreement with the known nonsphericity of {sup 6}Li indicated by its quadrupole moment. The sign of {ital T}{sub 20} in the {ital d} channel suggests that near {ital q}=0 the {ital D} state in {sup 6}Li has the same sign as in the deuteron; an abrupt change of sign near {ital q}=0.12 GeV/{ital c} is in agreement with theoretical expectation of a node in the {alpha}{ital d} position wave function. The {alpha}-channel data show larger {ital T}{sub 20} values than the {ital d} channel; in this case the small-{ital q}-region has not been explored enough to establish a similar node. A few data points in the {ital t} channel might suggest that {ital T}{sub 20} becomes positive above {ital q}=0.4 GeV/{ital c} in this case.

  2. NMR measurements of hyperpolarized 3He gas diffusion in high porosity silica aerogels

    OpenAIRE

    Tastevin, Geneviève; Nacher, Pierre-Jean

    2005-01-01

    Hyperpolarized 3He is used to nondestructively probe by NMR the structure of custom-made and commercial silica aerogels (97% and 98.5% porous). Large spin-echo signals are obtained at room temperature and very low magnetic field (2mT) even with small mounts of gas. Attenuation induced by applied field gradients results from the combined effects of gas diffusion and confinement by the porous medium on atomic motion. Nitrogen is used as a buffer gas to reach equivalent 3He pressures ranging fro...

  3. Neutron fluence determination at reactor filters by 3He proportional counters: Comparison of unfolding algorithms

    International Nuclear Information System (INIS)

    Multichannel pulse height measurements with a cylindrical 3He proportional counter obtained at a reactor filter of natural iron are taken to investigate the properties of three algorithms for neutron spectrum unfolding. For a systematic application of uncertainty propagation the covariance matrix of previously determined 3He response functions is evaluated. The calculated filter transmission function together with a covariance matrix estimated from cross-section uncertainties of the filter material is used as fluence pre-information. The results obtained from algorithms with and without pre-information differ in shape and uncertainties for single group fluence values, but there is sufficient agreement when evaluating integrals over neutron energy intervals

  4. 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...

  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. 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.

  7. Precision Measurement of the n-3He Incoherent Scattering Length Using Neutron Interferometry

    OpenAIRE

    Huber, M. G.; Arif, M.; Black, T. C.; W.C. Chen; Gentile, T. R.; Hussey, D. S.; Pushin, D.; Wietfeldt, F. E.; Yang, L

    2008-01-01

    We report the first measurement of the low-energy neutron-$^3$He incoherent scattering length using neutron interferometry: $b_i' = (-2.512\\pm 0.012{statistical}\\pm0.014{systematic})$ fm. This is in good agreement with a recent calculation using the AV18+3N potential. The neutron-$^3$He scattering lengths are important for testing and developing nuclear potential models that include three nucleon forces, effective field theories for few-body nuclear systems, and neutron scattering measurement...

  8. 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.

  9. 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.

  10. Liquid crystal polarimetry for metastability exchange optical pumping of {sup 3}He

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, J.D., E-mail: jdmax@mit.edu; Epstein, C.S.; Milner, R.G.

    2014-11-11

    We detail the design and operation of a compact, discharge light polarimeter for metastability exchange optical pumping of {sup 3}He gas near 1 torr under a low magnetic field. The nuclear polarization of {sup 3}He can be discerned from its electron polarization, measured via the circular polarization of 668 nm discharge light from an RF excitation. This apparatus measures the circular polarization of this very dim discharge light using a nematic liquid crystal wave retarder (LCR) and a high-gain, transimpedance amplified Si photodiode. We outline corrections required in such a measurement and discuss contributions to its systematic error.

  11. Decoupling between first sound and second sound in $^3$He - superfluid $^4$He mixtures

    OpenAIRE

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

    2016-01-01

    Bulk superfluid helium supports two sound modes: first sound is an ordinary pressure wave, while second sound is a temperature wave, unique to inviscid 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 $^3$He - superfluid $^4$He mixtures, between 1.6 K and 2.2 K, at $^3$He concentrations ranging from 0 to 11 %,...

  12. A SiPM-based ZnS:$^6$LiF scintillation neutron detector

    CERN Document Server

    Stoykov, A; Greuter, U; Hildebrandt, M; Schlumpf, N

    2014-01-01

    In the work presented here we built and evaluated a single-channel neutron detection unit consisting of a ZnS:$^6$LiF scintillator with embedded WLS fibers readout by a SiPM. The unit has a sensitive volume of 2.4 x 2.8 x 50 mm$^3$; 12 WLS fibers of diameter 0.25 mm are uniformly distributed over this volume and are coupled to a 1 x 1 mm$^2$ active area SiPM. We report the following performance parameters: neutron detection efficiency $\\sim 65\\,$% at $1.2\\,\\AA$, background count rate $< 10^{-3}$ Hz, gamma-sensitivity with $^{60}$Co source $< 10^{-6}$, dead time $\\sim 20\\,\\mu$s, multi-count ratio $< 1\\,$%. All these parameters were achieved up to the SiPM dark count rate of $\\sim 2\\,$MHz. We consider such detection unit as an elementary building block for realization of one-dimensional multichannel detectors for applications in the neutron scattering experimental technique. The dimensions of the unit and the number of embedded fibers can be varied to meet the specific application requirements. The upp...

  13. Neutron total and scattering cross sections of 6Li in the few MeV region

    International Nuclear Information System (INIS)

    Neutron total cross sections of 6Li are measured from approx. 0.5 to approx. 4.8 MeV at intervals of approx. 10 scattering angles and at incident-neutron intervals of approx.< 100 keV. Neutron differential inelastic-scattering cross sections are measured in the incident-energy range 3.5 to 4.0 MeV. The experimental results are extended to lower energies using measured neutron total cross sections recently reported elsewhere by the authors. The composite experimental data (total cross sections from 0.1 to 4.8 MeV and scattering cross sections from 0.22 to 4.0 MeV) are interpreted in terms of a simple two-level R-matrix model which describes the observed cross sections and implies the reaction cross section in unobserved channels; notably the (n;α)t reaction (Q = 4.783 MeV). The experimental and calculational results are compared with previously reported results as summarized in the ENDF/B-V evaluated nuclear data file

  14. Analysis of 6Li Scattering at 240 MeV Using Different Nuclear Potentials

    Science.gov (United States)

    Al-Ghamdi, A. H.; Ibraheem, Awad A.

    2016-06-01

    Angular distributions of the elastic and inelastic scattering cross sections of 6Li projectile on different heavy ion target nuclei including the 24Mg, 28Si, 48Ca, 58Ni, 90Zr, and 116Sn at energy of 240 MeV have been analyzed by using two different folded potentials based on the CDM3Y6 and São Paulo potentials for the real part of the optical potential, while the imaginary parts have a phenomenological Woods-Saxon shape. Coupled channel calculations for the low-lying 2+ state at 1.369, 1.779, 3.832, 1.454, 2.186, and 1.29 MeV for 24Mg, 28Si, 48Ca, 58Ni, 90Zr, and 116Sn, respectively, have been carried out, and the best fit values for B(EL) with the above models have been extracted by fitting the inelastic scattering cross section and compared with the values of previous works. The total reaction cross section and real and imaginary volume integrals have also been investigated.

  15. The Gas Motion Due To Non-Uniform Heating By 3He(n,p)3H Reactions In The Nuclear-Pumped3He -Lasers

    Science.gov (United States)

    Çetin, Füsun

    2007-04-01

    In the nuclear pumped-lasers, the passage of these energetic charged particles through gas results in a non-uniform volumetric energy deposition. This spatial non-uniformity induces a gas motion, which results in density and hence refractive index gradients that affects the laser's optical behaviour. The motion of 3He gas in a closed cavity is studied when it experiences transient and spatially non-uniform volumetric heating caused by the passage of 3He(n,p)3H reaction products. Gas motion is described by the radial velocity field of gas flow. Spatial and temporal variations of radial gas velocity are calculated for various tube parameters by using a dynamic energy deposition model. In the calculations, it is assumed that the laser tube is irradiated with neutrons from the pulse at a peak power of 1200 MW corresponding to a maximum thermal neutron flux of 8×1016 n / cm2sn in the central channel of ITU TRIGA Mark II Reactor. Results are examined.

  16. 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

  17. 3D MRI of non-Gaussian 3He gas diffusion in the rat lung

    Science.gov (United States)

    Jacob, Richard E.; Laicher, Gernot; Minard, Kevin R.

    2007-10-01

    In 3He magnetic resonance images of pulmonary air spaces, the confining architecture of the parenchymal tissue results in a non-Gaussian distribution of signal phase that non-exponentially attenuates image intensity as diffusion weighting is increased. Here, two approaches previously used for the analysis of non-Gaussian effects in the lung are compared and related using diffusion-weighted 3He MR images of mechanically ventilated rats. One approach is model-based and was presented by Yablonskiy et al., while the other approach utilizes the second order decay contribution that is predicted from the cumulant expansion theorem. Total lung coverage is achieved using a hybrid 3D pulse sequence that combines conventional phase encoding with sparse radial sampling for efficient gas usage. This enables the acquisition of nine 3D images using a total of only ˜1 L of hyperpolarized 3He gas. Diffusion weighting ranges from 0 s/cm 2 to 40 s/cm 2. Results show that the non-Gaussian effects of 3He gas diffusion in healthy rat lungs are directly attributed to the anisotropic geometry of lung microstructure as predicted by the Yablonskiy model, and that quantitative analysis over the entire lung can be reliably repeated in time-course studies of the same animal.

  18. 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.

  19. 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.

  20. Association of 3He-rich solar energetic particles with large-scale coronal waves

    Science.gov (United States)

    Bucik, Radoslav; Innes, Davina; Guo, Lijia; Mason, Glenn M.; Wiedenbeck, Mark

    2016-07-01

    Impulsive or 3He-rich solar energetic particle (SEP) events have been typically associated with jets or small EUV brightenings. We identify 30 impulsive SEP events from ACE at L1 during the solar minimum period 2007-2010 and examine their solar sources with high resolution STEREO-A EUV images. At beginning of 2007, STEREO-A was near the Earth while at the end of the investigated period, when there were more events, STEREO-A was leading the Earth by 90°. Thus STEREO-A provided a better (more direct) view on 3He-rich flares generally located on the western Sun's hemisphere. Surprisingly, we find that about half of the events are associated with large-scale EUV coronal waves. This finding provides new insights on acceleration and transport of 3He-rich SEPs in solar corona. It is believed that elemental and isotopic fractionation in impulsive SEP events is caused by more localized processes operating in the flare sites. The EUV waves have been reported in gradual SEP events in association with fast coronal mass ejections. To examine their role on 3He-rich SEPs production the energy spectra and relative abundances are discussed. R. Bucik is supported by the Deutsche Forschungsgemeinschaft under grant BU 3115/2-1.

  1. The reaction mechanism of the (3HE,T) reaction and applications to nuclear structure

    NARCIS (Netherlands)

    1986-01-01

    In this thesis we present a study on the reaction meachanism of the (3He,t) reaction at 70-80 MeV bombarding energy and on structures of the residual nuclei excited in this reaction: 24-Al, 26-Al, 28-P, 32-Cl, 40-Sc, 42-Sc and 58-Cu... Zie: Summary

  2. Study of the deeply bound hole states by the (3He,α) reaction

    International Nuclear Information System (INIS)

    The (3He,α) reactions at 110 - 120 MeV on even tin isotopes revealed the presence of the new (1g)-1 state at Ex = 6 -- 7 MeV with a spectroscopic factor comparable to the known (1g sub(9/2))-1 deeply bound hole state. (author)

  3. Observations of EUV Waves in 3He-Rich Solar Energetic Particle Events

    CERN Document Server

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

    2015-01-01

    Small 3He-rich solar energetic particle (SEP) events with their anomalous abundances, markedly different from solar system, provide evidence for a unique acceleration mechanism that operates routinely near solar active regions. Although the events are sometimes accompanied by coronal mass ejections (CMEs) it is believed that mass and isotopic fractionation is produced directly in the flare sites on the Sun. We report on a large-scale extreme ultraviolet (EUV) coronal wave observed in association with 3He-rich SEP events. In the two examples discussed, the observed waves were triggered by minor flares and appeared concurrently with EUV jets and type III radio bursts but without CMEs. The energy spectra from one event are consistent with so-called class-1 (characterized by power laws) while the other with class-2 (characterized by rounded 3He and Fe spectra) 3He-rich SEP events, suggesting different acceleration mechanisms in the two. The observation of EUV waves suggests that large-scale disturbances, in addit...

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

    OpenAIRE

    Scopetta, S.

    2004-01-01

    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.

  5. 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...

  6. 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...

  7. Neutron scattering from liquid {sup 3}He at large momentum transfers

    Energy Technology Data Exchange (ETDEWEB)

    Azuah, R.T. [Keele Univ. (United Kingdom). Dept. of Physics]|[Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Stirling, W.G. [Keele Univ. (United Kingdom). Dept. of Physics; Guckelsberger, K. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, Postfach 3345, 38116 Braunschweig (Germany); Scherm, R. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, Postfach 3345, 38116 Braunschweig (Germany)]|[Institut Laue-Langevin, BP 156X, F-38042 Grenoble (France); Glyde, H.R. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Bennington, S.M. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX (United Kingdom); Taylor, A.D. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX (United Kingdom)

    1995-08-01

    Neutron inelastic scattering measurements have been made on liquid {sup 3}He at 1.4 K for wave vectors between 9 and 20 A{sup -1}. The peak positions and widths are extracted and the mean kinetic energy determined. A new (theoretical) moment technique is used to investigate the momentum distribution and final-state effects. (orig.).

  8. sup 3 He neutron polarising filters -- theoretical comparison with supermirrors and Heusler alloy polarisers

    CERN Document Server

    Cussen, L D; Hicks, T J

    2000-01-01

    There is currently intense interest in the development of gaseous sup 3 He neutron polarising transmission filters. The key areas of development are increasing the currently achievable levels of nuclear spin polarisation, pi, within the sup 3 He gas and improving the reliability of the devices. Recent work has identified 'quality factors' which can be used to determine the optimum thickness of such filters under various experimental conditions. The best achievable quality factor for a sup 3 He polariser with a given pi is determined. It is demonstrated that the optimum filter thickness depends only weakly on pi and is always approximately given by the dimensionless expression rho sigma lambda t=3.4 where rho is the density of sup 3 He atoms in the filter, sigma is the absorption cross section at a wavelength of 1 A, lambda is the neutron wavelength in A and t is the filter thickness. Quality factors are calculated for existing types of neutron polariser (supermirrors and Heusler alloy monochromators) as a fun...

  9. {sup 3}He neutron polarising filters -- theoretical comparison with supermirrors and Heusler alloy polarisers

    Energy Technology Data Exchange (ETDEWEB)

    Cussen, L.D. E-mail: leocussen@vut.edu.au; Goossens, D.J.; Hicks, T.J

    2000-02-01

    There is currently intense interest in the development of gaseous {sup 3}He neutron polarising transmission filters. The key areas of development are increasing the currently achievable levels of nuclear spin polarisation, {pi}, within the {sup 3}He gas and improving the reliability of the devices. Recent work has identified 'quality factors' which can be used to determine the optimum thickness of such filters under various experimental conditions. The best achievable quality factor for a {sup 3}He polariser with a given {pi} is determined. It is demonstrated that the optimum filter thickness depends only weakly on {pi} and is always approximately given by the dimensionless expression {rho}{sigma}{lambda}t=3.4 where {rho} is the density of {sup 3}He atoms in the filter, {sigma} is the absorption cross section at a wavelength of 1 A, {lambda} is the neutron wavelength in A and t is the filter thickness. Quality factors are calculated for existing types of neutron polariser (supermirrors and Heusler alloy monochromators) as a function of instrumental parameters. These results are used to determine the 'break even' point for the new polarisers - the {pi} needed for the new polarisers to outperform existing types of polarisers. A quantitative discussion of regimes of usefulness of the different polariser types for all common instrument types is presented.

  10. The polarized 3He(d,p)4He reaction at Elab = 270Mev

    International Nuclear Information System (INIS)

    The 3He(d, p)4He reaction is one of the important processes in the primordial nuclearsynthesis of the universe. Furthermore, the reaction of a polarized 3He target with a polarized deuterium beam at E1ab = 270MeV would be an ambitious experiment in which a constraint on the deuteron D-state probability could be measured directly. Moreover, the reaction is interesting as an example of how to treat the five-body problem from a Faddeev theory point of view. Our approach involves coupled Faddeev equations for the 3He-p-n and d-d-p systems. Using two Faddeev equations, we obtained the scattering amplitudes 'Xhpn' and 'Xddp' for both the 3He-p-n and the d-d-p systems. Xhpn and Xddp were combined with each other by a proper normalization method. Finally, the differential cross section, the tensor analysing power, Ayy and Axx, the spin correlation coefficient, Cyy and Cxx, and the polarization correlation coefficient C// were investigated. We found that the amplitude Xhpn contributes mainly to the forward region of the differential cross section while Xddp contributes mainly to the backward region. Even for this calculation, the observables are smaller than the theoretical values at forward scattering angles. (author)

  11. Experimental Research of the Radiative Capture of Thermal Neutrons in $^{3}$He

    CERN Document Server

    Bystritsky, V M; Enik, T L; Filipowicz, M; Gerasimov, V V; Grebenyuk, V M; Kobzev, A P; Kublikov, R V; Nesvizhevsky, V V; Parzhitskii, S S; Pavlov, V N; Popov, N P; Salamatin, A V; Shvetsov, V N; Slepnev, V M; Strelkov, A V; Wozniak, J; Zamyatin, N I

    2006-01-01

    A project of an experiment on measurement of the cross sections of radiative thermal neutron capture by $^{3}$He nuclei with production of one and two $\\gamma $-quanta ($n_{\\rm th}+^{3}$He $\\to \\alpha + \\gamma $(2$\\gamma $)) is presented. The interest in studying the processes is dictated by the following factors: a possibility of obtaining information on parameters of the nucleon $N$-$N$ potential and structure of exchange meson currents; a possibility of verifying the model of the mechanism for nucleon capture by the nucleus $^{3}$He in the low-energy region; necessity to solve some questions existing in astrophysics. The experiment is planned to be carried out on the PF1B beam of ILL reactor (Grenoble). The target is a hollow cylinder of pure aluminium ($\\varnothing$140$\\times $80~mm) filled with $^{3}$He and $^{4}$He (background experiment) at the pressure 2~atm. Registration of the $\\gamma $-quanta is carried out by four BGO crystal ($\\varnothing$100$\\times $70~mm) detectors. According to the calculation...

  12. 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.

  13. Connection between the 3HE-enrichment and spectral index of solar energetic particles

    International Nuclear Information System (INIS)

    A model is presented which explains the observed tendency of events with large He-3/He-4 ratios to have steeper spectra. In this model preferential injection of He-3, acceleration by Alfven waves and Coulomb deceleration of ions are considered simultaneously. The observed tendency may be obtained as a result of competition between injection and acceleration processes

  14. On temperature variations during 3He Polarization experiments in Pomeranchuk cells

    DEFF Research Database (Denmark)

    Geng, Q.; Rasmussen, Finn Berg

    1984-01-01

    Simple model calculations have been performed in relation to temperature changes in decompression experiments with Pomeranchuk cells, aiming at the production of spin polarized liquid **3He. Comparison with reported experiments indicates that thermal contact with the surroundings is too strong...

  15. 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

    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...

  16. Possibility of Establishing D-3He Fusion Reactor Using Spherical Tokamaks

    Institute of Scientific and Technical Information of China (English)

    石秉仁

    2004-01-01

    Based on the recent progress in the spherical torus approach (ST), it is meaningful to revisit the possibility of establishing D-3He fusion reactor using both the ST and the tokamak scaling. Fundamental requirements then are obtained and some important issues are discussed. The wall reflection of the synchrotron radiation is very important for a good reactor merit.

  17. (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.

  18. 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

  19. 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.

  20. Precise determination of 6Li cold collision parameters by radio-frequency spectroscopy on weakly bound molecules

    International Nuclear Information System (INIS)

    We employ radio-frequency spectroscopy on weakly bound 6Li2 molecules to precisely determine the molecular binding energies and the energy splittings between molecular states for different magnetic fields. These measurements allow us to extract the interaction parameters of ultracold 6Li atoms based on a multichannel quantum scattering model. We determine the singlet and triplet scattering lengths to be as=45.167(8)a0 and at=-2140(18)a0 (1a0=0.052 917 7 nm), and the positions of the broad Feshbach resonances in the energetically lowest three s-wave scattering channels to be 83.41(15), 69.04(5), and 81.12(10) mT

  1. 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.

  2. 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.

  3. Neutron detection and identification using ZnS:Ag/{sup 6}LiF in segmented antineutrino detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kiff, Scott D., E-mail: skiff@sandia.gov [Sandia National Laboratories, 7011 East Avenue, Livermore, CA 94550 (United States); Bowden, Nathaniel [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Lund, Jim; Reyna, David [Sandia National Laboratories, 7011 East Avenue, Livermore, CA 94550 (United States)

    2011-10-01

    Antineutrino detection using inverse beta-decay conversion has demonstrated capability to measure nuclear reactor power and fissile material content for nuclear safeguards. Current efforts focus on aboveground deployment scenarios, for which a successful background rejection strategy will be needed to measure the anticipated antineutrino event rates. In this paper, we report on initial studies to quantify the intrinsic capture efficiency and particle identification capabilities of a new scintillation-based segmented design that uses layers of ZnS:Ag/{sup 6}LiF to capture and identify neutrons created in the inverse beta-decay reaction. Laboratory efficiency measurements are consistent with MCNP5 calculations, estimating {sup 6}Li neutron conversion efficiency above 50% for practical full-scale detector configurations.

  4. Influence of the separation of the centre-of-mass motion on the charge form factor of /sup 6/Li

    Energy Technology Data Exchange (ETDEWEB)

    Bouten, M. (Limburgs Universitair Centrum (Belgium)); Bouten, M.C. (Centre d' Etude de l' Energie Nucleaire, Mol (Belgium))

    1982-12-01

    An exact calculation is carried out for the charge form factor of /sup 6/Li using a wavefunction for the ground state which depends on the internal coordinates only and which contains a short-range correlation factor of the Jastrow type. A very good fit to the experimental data can be obtained by adjusting the parameters in the wavefunction. It is found that the optimum value of these parameters depends sensitively on the way the centre-of-mass coordinate is eliminated.

  5. Examination of the Coulomb-nuclear interference in inelastic scattering of 6Li in 76Ge

    International Nuclear Information System (INIS)

    The inelastic scattering of 28,0 MeV 6Li on 76Ge in the excitation of the 2+1 state, has been studied with the Coulomb-Nuclear Interference (CNI) analysis. The data were measured at the Pelletron-Enge-Spectrograph facility at LAFN-IFUSP. A solid-state position sensitive silicon detector (PSD) (500μm thickness and 47 × 8 mm2 area) was used to measure the data at the spectrometer focal plane. Digital pulse processing (DPP) was implemented in the acquisition system. Twenty-six spectra were measured at carefully chosen scattering angles in the range of 10 deg ≤ θLab ≤ 55 deg to obtain an angular distribution. The analysis was performed with the Distorted Wave Born Approximation (DWBA) and applied for the nuclear transition potential, the Deformed Optical Potential Model (DOMP), under well-established global optical parameters. The fit of the predicted cross sections to the experimental data through χ2 minimization, using the iterative method of Gauss, allowed for the extraction of the correlated parameters, δN2, the mass deformation length, and C2 = ΝC2/δN2, the ratio between charge and mass deformation lengths. The correlated parameters obtained in the present work were C2 = 1,101 (20) and δN2 = 1,08(21)fm. Statistical tests, through a Monte Carlo simulation of 5000 new data sets, validated the method employed in the correlated parameters fit. The methodology applied for the CNI analysis allowed the extraction of ratio B(EL)/B(ISL), which is proportional to the square of C2, with a good precision due to the scale uncertainties cancellation of the absolute cross sections. The values of B(IS2) and of the ratios B(E2)/B(IS2) obtained in the present work have not been reported before and allow the study of the evolution of the collectivity throughout the even-A germanium chain together with former results obtained for the 70,72,74Ge isotopes. The results along the chain indicate that although the protons relative to the neutrons reveal a small predominant

  6. 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.

  7. 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.

  8. Probing Bogoliubov Quasiparticles in Superfluid ^3He with a `Vibrating-Wire Like' MEMS Device

    Science.gov (United States)

    Defoort, M.; Dufresnes, S.; Ahlstrom, S. L.; Bradley, D. I.; Haley, R. P.; Guénault, A. M.; Guise, E. A.; Pickett, G. R.; Poole, M.; Woods, A. J.; Tsepelin, V.; Fisher, S. N.; Godfrin, H.; Collin, E.

    2016-05-01

    We have measured the interaction between superfluid ^3He-B and a micro-machined goalpost-shaped device at temperatures below 0.2 T_c. The measured damping follows well the theory developed for vibrating wires, in which the Andreev reflection of quasiparticles in the flow field around the moving structure leads to a nonlinear frictional force. At low velocities, the damping force is proportional to velocity, while it tends to saturate for larger excitations. Above a velocity of 2.6 mm s^{-1}, the damping abruptly increases, which is interpreted in terms of Cooper-pair breaking. Interestingly, this critical velocity is significantly lower than that reported with other mechanical probes immersed in superfluid ^3He. Furthermore, we report on a nonlinear resonance shape for large motion amplitudes that we interpret as an inertial effect due to quasiparticle friction, but other mechanisms could possibly be invoked as well.

  9. 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.

  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. Constraining short-range spin-dependent forces with polarized $^3$He

    CERN Document Server

    Guigue, Mathieu; Petukhov, Alexander K; Pignol, Guillaume

    2015-01-01

    We have searched for a short-range spin-dependent interaction using the spin relaxation of hyperpolarized $^3$He. Such a new interaction would be mediated by a hypothetical light scalar boson with \\CP-violating couplings to the neutron. The walls of the $^3$He cell would generate a pseudomagnetic field and induce an extra depolarization channel. We did not see any anomalous spin relaxation and we report the limit for interaction ranges $\\lambda$ between $1$ and $100~\\rm{\\mu m}$: $g_sg_p \\lambda ^2 \\leq 2.6\\times 10^{-28}~\\mathrm{m^2}\\, ( 95~\\%\\, \\mathrm{C.L.})$, where $g_s$($g_p$) are the (pseudo)scalar coupling constant, improving the previous best limit by 1 order of magnitude.

  12. Neutron scattering from liquid {sup 3}He at intermediate to large wavevectors

    Energy Technology Data Exchange (ETDEWEB)

    Azuah, R.T.; Stirling, W.G. [Keele Univ. (United Kingdom); Guckelsberger, K. [PTB, Braunschweig (Germany)] [and others

    1995-12-01

    Neutron inelastic scattering experiments have been performed on liquid {sup 3}He at saturated vapour pressure and T = 1.4 K covering a wide range of energy and momentum transfers (9 {le} Q {le} 20 {angstrom}{sup -1}). Allowing for the very strong {sup 3}He neutron absorption, the data is of excellent quality and it has been analysed to extract information on the scattering function widths, peak positions and single particle kinetic energies. It is found that there are no width oscillations with momentum transfer and that the average atomic kinetic energy is approximately 20% lower than theoretical predictions, in agreement with previous neutron scattering results. A new method of analysis aimed at extracting both the atomic momentum distribution and final state effects is also presented and the results discussed in the light of current theory.

  13. Introduction to the vortex sheet of superfluid 3He-A

    International Nuclear Information System (INIS)

    It is well known that superfluids respond to rotation by forming vortex lines. It has been recently discovered that a different type of state consisting of a vortex sheet, instead of lines, can be created in the A phase of superfluid 3He. This paper presents an introduction to the vortex sheet. We first discuss 4He, where a vortex sheet is unstable. The way to realize a stable sheet in 3He-A is called a vortex soliton. It consists of a topologically stable domain wall to which nonsingular vorticity is bound. The vortex soliton has been observed by nuclear magnetic resonance, and its most prominent experimental properties are explained. The macroscopic shape of the sheet and the superfluid flow in a rotating container are discussed. (orig.)

  14. Spin-Correlation Coefficients and Phase-Shift Analysis for p+$^3$He Elastic Scattering

    CERN Document Server

    Daniels, T V; Cesaratto, J M; Clegg, T B; Couture, A H; Karwowski, H J; Katabuchi, T

    2010-01-01

    Angular Distributions for the target spin-dependent observables A$_{0y}$, A$_{xx}$, and A$_{yy}$ have been measured using polarized proton beams at several energies between 2 and 6 MeV and a spin-exchange optical pumping polarized $^3$He target. These measurements have been included in a global phase-shift analysis following that of George and Knutson, who reported two best-fit phase-shift solutions to the previous global p+$^3$He elastic scattering database below 12 MeV. These new measurements, along with measurements of cross-section and beam-analyzing power made over a similar energy range by Fisher \\textit{et al.}, allowed a single, unique solution to be obtained. The new measurements and phase-shifts are compared with theoretical calculations using realistic nucleon-nucleon potential models.

  15. Neutron radiography of a static density gradient of 3He gas at cryogenic temperatures

    Science.gov (United States)

    Wichmann, G.; Antognini, A.; Eggenberger, A.; Kirch, K.; Piegsa, F. M.; Soler, U.; Stahn, J.; Taqqu, D.

    2016-04-01

    We demonstrate a stationary helium gas density gradient which is needed for a proposed novel low-energy μ+ beam line. In a closed system with constant pressure the corresponding density gradient is only a function of the temperature. In a neutron radiography experiment two gas cells with different geometries were filled with 3He gas at constant pressures of about 10 mbar. Temperatures in the range from 6 K to 40 K were applied and density distributions with a maximum to minimum density ratio of larger than 3 were realized. The distribution was investigated employing the strongly neutron absorbing isotope 3He. A simple one-dimensional approach derived from Fourier's law describes the obtained gas density with a deviation < 2 %.

  16. 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...

  17. 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)

  18. Depth profiling of deuterium with the D(3He,p)4He reaction

    International Nuclear Information System (INIS)

    The use of the nuclear reaction D(3He,p)4He for the depth profiling of deuterium was studied. The detection at backward angles of the protons which have energies in excess of 13 MeV, presents distinct advantages with respect to the more conventional method of detecting the associated α particles. The various contributions to the depth resolution in α-Si have been measured or calculated, taking into account detector acceptance angle, size of the probing 3He beam, energy straggling, multiple scattering and lateral spread contributions. Sensitivities are discussed with respect to depth resolution requirements. The method has been applied to deuterium depth profiling in amorphous silicon hydrogenated by implantation or plasma diffusion of deuterium. (orig.)

  19. 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.

  20. A Light-Front Approach to the 3He Spectral Function

    Science.gov (United States)

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

    2015-09-01

    The analysis of semi-inclusive deep inelastic electron scattering off polarized 3He 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 3He, which takes care of the final state interaction effects. This quantity is introduced in the non-relativistic case, and its generalization in a Poincaré 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.

  1. 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.

  2. 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.

  3. 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.

  4. Energy dissipation and multifragment decay in the 3He+natAg system

    International Nuclear Information System (INIS)

    Multifragment emission data from the 3He+Ag reaction are examined in the context of an intranuclear cascade code followed by an expanding, emitting source calculation. The role of Δ resonances in the energy dissipation process is stressed. In addition, the importance of employing a distribution of excitation energies in such analyses is pointed out. In order to describe the data within the context of this hybrid model, excitation via Δ resonance formation and expansion of the emitting source are required

  5. Positive parity levels populated in the 17O(3He,p)19F reaction

    International Nuclear Information System (INIS)

    Positive parity levels in 19F populated in the 17O(3He,p) reaction are studied upto Esub(x) approx.=7 MeV. The angular distributions of the levels are studied in terms of the DWBA method of single-step process using two-particle spectroscopic amplitudes derived from (sd) shell model calculations. The difference in shape presented by different levels of the same Jsup(π)-value is well given by the shell model amplitudes. (author)

  6. Orienting effect of vortices on the directrix of rotating 3He--B

    International Nuclear Information System (INIS)

    The combined effect of a magnetic field and superfluid vortex flows on the equilibrium orientation of the directrix of rotating 3He--B is theoretically investigated. It is shown that the presence of vortices is revealed by a shift in the transverse-NMR frequency, the effect being greatest when the external magnetic field is inclined at an angle of theta = π/4 to the axis of rotation

  7. Continuous vortices with broken symmetry in rotating superfluid 3He-A

    International Nuclear Information System (INIS)

    New NMR measurements are reported on continuous 3He-A vortices in tilted magnetic fields. We introduce a symmetry classification of the continuous vortices with broken axial symmetry. It is found that the discrete internal symmetry may in addition be broken in two inequivalent ways, producing two different continuous vortices. Although NMR may not distinguish between these two vortices, the observed vortex satellite peak is well accounted for by spin waves localized in the soft cores of such vortices

  8. A search for disordered (glassy) phase in solid 3He deformed in situ

    OpenAIRE

    Lisunov, A. A.; Maidanov, V. A.; Rubanskiy, V. Yu.; Rubets, S. P.; Rudavskii, E. Ya.; Rybalko, A. S.; Tikhii, V. A.

    2010-01-01

    A disordered (glassy) state has been searched in solid 3He deformed in the course of experiment employing precise measurements of pressure. The analysis of the temperature dependence of the crystal pressure measured at a constant volume shows that the main contribution to the pressure is made by the phonon subsystem, the influence of the disordered phase being very weak. Annealing of the deformed crystal does not affect this state. The results obtained differ greatly from the corresponding da...

  9. Testing on novel neutron detectors as alternative to 3He for security applications

    International Nuclear Information System (INIS)

    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 3He technology. Unfortunately, in the last few years the market of 3He 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 3He. 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 3He. -- Highlights: ► The paper tackles the problem of lack of He-3 supply. ► This impacts neutron detection for security applications. ► The aim is to test innovative/alternative solutions for neutron detectors. ► Encouraging results obtained with organic and Li-based scintillators.

  10. Diffraction model analysis of polarized triton and 3He elastic scattering

    International Nuclear Information System (INIS)

    The differential cross-section and analyzing power angular distributions are presented for the elastic scattering of polarized 3H from 40Ca and 58Ni at 17MeV and 3He from 26Mg, 27Al and 58Ni at different energies. The data obtained for spin 1/2 strongly absorbed particles elastically scattered by spinless targets are analyzed by the diffraction model. (author)

  11. Isotopic separation of 3He/4He from solar wind gases evolved from the lunar regolith

    International Nuclear Information System (INIS)

    The potential benefits of 3He when utilized in a nuclear fusion reactor to provide clean, safe electricity in the 21st century for the world's inhabitants has been documented. Unfortunately, He is scarce on earth. Large quantities of 3He, perhaps a million tonnes, are embedded in the lunar regolith, presumably implanted by the solar wind together with other elements, notably 4He, H, C and N. Several studies have suggested processing the lunar regolith and recovering these valuable solar wind gases. Once released, these gases can be separated for use. The separation of helium isotopes is described in this paper. 3He constitutes only 400 at·ppm of lunar He, too dilute to separate economically by distillation alone. A ''superfluid'' separator is being considered to preconcentrate the 3He. The superfluid separator consists of a porous filter in a tube maintained at a temperature of 2.17 K or less. Although the 4He, which is superfluid below 2.17 K, flows readily through the filter, the He is blocked by the filter, and becomes enriched at the feed end. He can be enriched to about 10% in such a system. The enriched product from the superfluid separation serves as a feed to a distillation apparatus operating at a pressure of 9 kPa, with a boiler temperature of 2.4 K, and a condenser temperature of 1.6 K. Under constant flow conditions, a 99.9% enriched He product can be produced in this apparatus. The heat rejection load of the refrigeration equipment necessary to cool the separation operations would be conducted during the lunar nights

  12. Final-State Spectrum of $^3$He after $\\beta^-$ Decay of Tritium Anions T$^-$

    OpenAIRE

    Stark, Alexander; Saenz, Alejandro

    2009-01-01

    The final-state spectrum of $\\beta$ decaying tritium anions T$^-$ was calculated. The wavefunctions describing the initial T$^-$ ground state and the final $^3$He states were obtained by the full configuration-interaction method. The transition probability was calculated within the sudden approximation. The transition probability into the electronic continuum is extracted from the complex-scaled resolvent and is shown to converge for very high-energies to an approximate analytical model proba...

  13. Discrete nuclear-elastic-scattering effects in Cat-D and D-3He fusion plasmas

    International Nuclear Information System (INIS)

    The effects of Nuclear Elastic Scattering (NES) of fusion products are investigated for Cat-D and D-3He plasmas. It is found that accounting for the discrete nature of the large energy transfer associated with NES is necessary to accurately calculate the plasma distribution functions, and effects on overall plasma characteristics such as ignition requirements. For cases where cyclotron losses are important, inclusion of NES can reduce the ignition requirements by 50%

  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 3He 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 3He diffusion attenuated MR signal in lungs in terms of two diffusion coefficients—longitudinal (D) and transverse (D) with respect to the individual acinar airway axis [Yablonskiy et al., PNAS 99 (2002) 3111]. In this paper, empirical relationships between D and D 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 and D 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 3He diffusion MRI, despite the airways being too small to be resolved by direct imaging. These results also predict a rather substantial dependence of 3He ADC on the experimentally-controllable diffusion time, Δ. If Δ 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. A broadband Ytterbium-doped tunable fiber laser for 3He optical pumping at 1083 nm

    OpenAIRE

    Tastevin, Geneviève; Grot, Sébastien; Courtade, Emmanuel; Bordais, Sylvain; Nacher, Pierre-Jean

    2004-01-01

    Submitted: July 2003, Published online: December 2003, Published: Appl. Phys. B 78 (2004) 145-156. Copyright : Springer-Verlag 2003 (http://www.springerlink.com). V3: symbols corrected in Figs 10-11; minor final changes included. Large amounts of hyperpolarized 3He gas with high nuclear polarization rates are required for use in neutron spin filters or nuclear magnetic resonance imaging of human lung. Very high efficiency can be obtained by metastability exchange optical pumping using mult...

  17. Emphysematous changes and normal variation in smokers and COPD patients using diffusion 3He MRI

    International Nuclear Information System (INIS)

    Introduction: This study aims to quantify global and regional changes of diffusive motion of 3He gas within the lung, as determined by hyperpolarized 3He MR apparent diffusion coefficient (ADC) measurement, in non-smokers, smokers and chronic obstructive pulmonary disease (COPD) patients. Methods: Age-matched groups of six healthy non-smokers, five healthy smokers and five patients with COPD. The experiments were performed with approval from the local Research Ethics Committee. Diffusion imaging was performed following hyperpolarized 3He gas inhalation, producing ADC maps. Mean and standard deviation of the ADCs were used to compare the subject groups and assess regional variations within individuals. Results: The intra-individual standard deviation of ADC in the healthy smokers was significantly larger than that of the non-smoking group (P < 0.02). Compared to the non-smoking group, COPD patients had significantly higher mean and standard deviation of ADC (P < 0.01). The mean ADC in the anterior half of the chest was systematically higher than in the posterior half in the healthy non-smoking subject group. Discussion: This study suggests that there are regional trends in the ADC values of healthy volunteers that may have implications for the clinical interpretation of ADC values. Less homogeneous ADC values have been detected in asymptomatic smokers, indicative of damage to the distal air spaces

  18. Saddle point condition for D minus sup 3 He tokamak fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mitarai, O. (Kumamoto Inst. of Technology, Dept. of Electrical Engineering, Ikeda 4-22-1, Kumamoto 860 (JP)); Hirose, A.; Skarsgard, H.M. (Univ. of Saskatchewan, Dept. of Physics Sasakatoon, Saskatchewan, S7N 0W0 (CA))

    1991-03-01

    In this paper the concept of a generalized ignition contour map, showing {bar P}{sub ht}T{sup 2}{sub E}, NT{sub E}, and T, is used to study the ignition criterion for a D{minus}{sup 3}He fusion reactor with plasma temperature and density profiles. Direct heating scenarios to the D {minus} {sup 3}He ignition regime without the help of deuterium-tritium burning are considered. The machine size and enhancement factor for the confinement time required to reach D {minus} {sup 3}He ignition can be simple determined by comparing the height of the operation path with Goldston L-mode scaling and the height of the generalized saddle point. A confinement enhancement factor of 2 to 3 is required in the case of a large plasma current (30 to 80 MA) in a small-aspect-ratio tokamak. On the other hand, for a small plasma current ({approx lt} 10 MA), large-aspect-ratio tokamak, an enhancement factor of 5 to 6 is necessary to reach ignition. Fuel dilution effects by fusion products and impurities, the confinement degradation effect due to 14-MeV protons, and the operation paths are also considered. To lower the height of the saddle point, and hence the auxiliary heating power, we optimize the fuel composition and examine operation in the hot ion mode.

  19. 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.

  20. 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.

  1. 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.

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

    International Nuclear Information System (INIS)

    We measured the differential cross section and the spin correlation parameter Cyy of the p-vector+3He-vector elastic backward scattering at 200, 300, and 400 MeV at θ=180 deg. in the center-of-mass frame to study the mechanism of the reaction and to examine the validity of the 3He wave functions based on two different realistic two-body forces. This is the first measurement of the spin correlation parameter Cyy of the p-vector+3He-vector EBS at intermediate energies. The experimental results were compared with few-body calculations, including three reaction mechanisms: two-nucleon-pair exchange, pion exchange, and direct pp scattering. It was found that few-body calculations describe the differential cross-section data reasonably well. The spin correlation parameter Cyy shows clear evidence for the two-nucleon-pair exchange processes in the reaction, demonstrating that the spin observables are helpful for deeper understanding of the reaction mechanism

  3. 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.

  4. Hyperpolarized 3He Functional Magnetic Resonance Imaging of Bronchoscopic Airway Bypass in Chronic Obstructive Pulmonary Disease

    Directory of Open Access Journals (Sweden)

    Lindsay Mathew

    2012-01-01

    Full Text Available A 73-year-old exsmoker with Global initiative for chronic Obstructive Lung Disease stage III chronic obstructive pulmonary disease underwent airway bypass (AB as part of the Exhale Airway Stents for Emphysema (EASE trial, and was the only EASE subject to undergo hyperpolarized 3He magnetic resonance imaging for evaluation of lung function pre- and post-AB. 3He magnetic resonance imaging was acquired twice previously (32 and eight months pre-AB and twice post-AB (six and 12 months post-AB. Six months post-AB, his increase in forced vital capacity was <12% predicted, and he was classified as an AB nonresponder. However, post-AB, he also demonstrated improvements in quality of life scores, 6 min walk distance and improvements in 3He gas distribution in the regions of stent placement. Given the complex relationship between well-established pulmonary function and quality of life measurements, the present case provides evidence of the value-added information functional imaging may provide in chronic obstructive pulmonary disease interventional studies.

  5. Comparison of various stopping gases for {sup 3}He-based position sensitive neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Doumas, A. [United States Merchant Marine Academy, Steamboat Road, Kings Point, NY 11024 (United States); Smith, G.C., E-mail: gsmith@bnl.gov [Instrumentation Division, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2012-05-21

    A range of solid state, scintillator and gas based detectors are being developed for use at the next generation of high flux neutron facilities. Since gas detectors are expected to continue to play a key role in future specific thermal neutron experiments, a comparison of the performance characteristics of prospective stopping gases is beneficial. Gas detectors typically utilize the reaction {sup 3}He(n,p)t to detect thermal neutrons; the {sup 3}He gas is used in a mixture containing a particular stopping gas in order to maintain relatively short ranges for the proton and triton pair emitted from the n-{sup 3}He reaction. Common stopping gases include hydrocarbons (e.g. propane), carbon tetrafluoride, and noble gases such as argon and xenon. For this study, we utilized the Monte Carlo simulation code 'Stopping and Range of Ions in Matter' to analyze the expected behavior of argon, xenon, carbon dioxide, difluoroethane and octafluoropropane as stopping gases for thermal neutron detectors. We also compare these findings to our previously analyzed performance of propane, butane and carbon tetrafluoride. A discussion of these gases includes their behavior in terms of proton and triton range, ionization distribution and straggle.

  6. Long-range states in excited ultracold 3He*-4He* dimers

    CERN Document Server

    Cocks, Daniel G; Whittingham, Ian B

    2014-01-01

    Long-range bound states of the excited heteronuclear 3He*--4He* system that dissociate to either 3He(1s2s 3S_1) + 4He(1s2p 3P_j) or 3He(1s2p 3P_j) + 4He(1s2s 3S_1), where j=0, 1, 2, are investigated using both single-channel and multichannel calculations in order to analyse the effects of Coriolis and non-adiabatic couplings. The multichannel calculations predict two groups of resonances above the lowest asymptotic energy. One of these groups dissociates to an atomic pair with the 2p excitation on the fermionic atom and the other dissociates to two asymptotes which correspond to the 2p excitation on either atom. Many of these resonances could be identified with levels in the single-channel calculation although the differences in energies were large. The total parity was found to have a significant influence on the ability to make these identifications. No purely bound states were found, although several resonances with line widths smaller than 1 MHz were obtained.

  7. 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...

  8. Degassing of 3H/3He, CFCs and SF6 by denitrification: measurements and two-phase transport simulations.

    Science.gov (United States)

    Visser, Ate; Schaap, Joris D; Broers, Hans Peter; Bierkens, Marc F P

    2009-01-26

    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 groundwater age tracers under agricultural land where denitrification causes degassing. We were able to reproduce the amount of degassing (R2=69%), as well as the 3H (R2=79%) and 3He (R2=76%) concentrations observed in a 3H/3He data set using simple 2D models. We found that the TDG correction of the 3H/3He age overestimated the control 3He/3He age by 2.1 years, due to the accumulation of 3He in the gas phase. The total uncertainty of degassed 3H/3He ages of 6 years (+/-2 sigma) is due to the correction of degassed 3He using the TDG method, but also due to the travel time in the unsaturated zone and the diffusion of bomb peak 3He. CFCs appear to be subject to significant degradation in anoxic groundwater and SF6 is highly susceptible to degassing. We conclude that 3H/3He is the most reliable method to date degassed groundwater and that two-phase flow models such as STOMP are useful tools to assist in the interpretation of degassed groundwater age tracer data. PMID:19042054

  9. 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

  10. 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.

  11. Neutron production rates during four transitions from DT to D3He ignited plasmas in a compact tokamak

    International Nuclear Information System (INIS)

    Neutron production rates (due to DT, DD, TT and T3He reactions) and D3He reaction rate during four transitions from DT to D3He ignited plasmas (characterized by different evolutions of ion densities and temperature) in a compact tokamak have been calculated. In this paper, for each transition, the results are reported in graphical form (one curve for each reaction) and shortly discussed. The main feature is the predominance of 14 MeV DT-neutrons, whose production rate does not appear to be negligible. It is therefore concluded that while acceptable in experiments of D3He ignition, tritium-assistance may not be suitable for routine startup of D3He fusion power plants, in which plasma temperature will hae to be raised to ignition level probably by other means. Mention to a program aimed at measuring cross sections of some neutron-lean fusion reactions is also made

  12. 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.

  13. A self-contained 3He refrigerator suitable for long duration balloon experiments

    Science.gov (United States)

    Masi, S.; Aquilini, E.; Cardoni, P.; de Bernardis, P.; Martinis, L.; Scaramuzzi, F.; Sforna, D.

    We describe the design, development and test of a self-contained 3He fridge, aimed to cool at ≲0.3 K a bolometric detection system with a hold time of two weeks. The system is robust and suitable for operation on a long-duration stratospheric balloon payload. A physical model of the fridge has been developed, which describes the measured hold time, limiting temperature and load curve of the fridge. The system has been flight tested successfully during two balloon flights of the BOOMERanG payload in summer 1997.

  14. Observations of homogeneous phase separation in liquid He3-He4 mixtures

    Science.gov (United States)

    Hoffer, J. K.; Campbell, L. J.; Bartlett, R. J.

    1980-01-01

    The so-called miscibility gap that exists below the critical point in liquid He-3 - H-4 mixtures makes it possible to study binary phase composition, and the ensuing dispersions, in a system possessing an additional order parameter in one of the components. The physical behavior of a superfluid dispersion produced by pressure quenching an He-3 - He-4 mixture into the miscibility gap is described. The description applies both to quenches of homogeneous and phase-separated initial states in various regions of the miscibility gap.

  15. Single Particle and Fermi Liquid Properties of He-3/--He-4 Mixtures: A Microscopic Analysis

    OpenAIRE

    Krotscheck, E.; Paaso, J.; Saarela, M.; Schoerkhuber, K.; Zillich, R.

    1998-01-01

    We calculate microscopically the properties of the dilute He-3 component in a He-3/--He-4 mixture. These depend on both, the dominant interaction between the impurity atom and the background, and the Fermi liquid contribution due to the interaction between the constituents of the He-3 component. We first calculate the dynamic structure function of a He-3 impurity atom moving in He-3. From that we obtain the excitation spectrum and the momentum dependent effective mass. The pole strength of th...

  16. NMR Response of a Vortex Tangle in Rotating 3He-B

    International Nuclear Information System (INIS)

    Following the injection of vortex loops into an originally vortex-free sample of superfluid 3He-B at T < 0.6Tc, transient states appear which exhibit a modified response in transverse NMR experiments when compared with the response from the final equilibrium state of rectilinear vortices. Here we investigate the NMR response of a model state where a random vortex tangle is assumed to be superimposed on the equilibrium vortex state. We show that this model can qualitatively account for the experimental findings, provided that the tangle is anisotropic

  17. Orientational effect of uniaxially deformed aerogel on the order parameter of superfluid $^3He$

    OpenAIRE

    Surovtsev, E. V.

    2008-01-01

    Effect of uniaxially-deformed aerogel on orientation of the order parameter of superfluid $^3He$ is considered. Approach used takes into account correlations in positions of particles forming aerogel. Calculations show that for the case of the B-like phase in the uniaxially-stretched aerogel deformation on the order of $10^{-2}\\div10^{-4}$ is already strong enough to achieve orientation of the order parameter which is different from that required by magnetic field in bulk liquid. For the A-li...

  18. Manipulating textures of rotating superfluid 3 He- A phase in a single narrow cylinder

    OpenAIRE

    Kunimatsu, T.; Nema, H.; Ishiguro, R; Kubota, M.; Takagi, T; Sasaki, Y.; Ishikawa, O

    2014-01-01

    We investigated order parameter textures of the rotating superfluid 3 He-A phase in a single narrow cylinder witha diameter of about 10 times the dipole coherence length by the cw-NMR method. It is theoretically proposedthat in such a narrow cylinder, a few special textures will appear due to the confinement in a cylindrical geometry.We observed three types of NMR spectra in the A phase. The NMR spectra of the textures were identified bya comparison with the spin waves excited in the NMR pote...

  19. 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.

  20. 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.

  1. Two-nucleon momentum distributions measured in 3He(e,e'pp)n.

    Science.gov (United States)

    Niyazov, R A; Weinstein, L B; Adams, G; Ambrozewicz, P; Anciant, E; Anghinolfi, M; Asavapibhop, B; Asryan, G; Audit, G; Auger, T; Avakian, H; Bagdasaryan, H; Ball, J P; Barrow, S; Battaglieri, M; Beard, K; Bektasoglu, M; Bellis, M; Benmouna, N; Berman, B L; Bertozzi, W; 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; Dashyan, N; DeVita, R; Degtyarenko, P V; Denizli, H; Dennis, L; Dharmawardane, K V; Dhuga, K S; Djalali, C; Dodge, G E; Doughty, D; 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; Gilad, S; Gilfoyle, G P; Giovanetti, K L; Girard, P; Gordon, C I O; Gothe, R W; Griffioen, K; Guidal, M; Guillo, M; 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; Ingram, W; Ito, M M; Jenkins, D; Joo, K; Juengst, H G; Kelley, J H; Kellie, J; 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; Kuhn, J; Lachniet, J; Laget, J M; Langheinrich, J; Lawrence, D; Li, Ji; Livingston, K; Lukashin, K; Manak, J J; Marchand, C; McAleer, S; McLauchlan, S; McNabb, J W C; Mecking, B A; Mehrabyan, S; Melone, J J; Mestayer, M D; Meyer, C A; Mikhailov, K; Mirazita, M; Miskimen, R; Morand, L; Morrow, S A; Muccifora, V; Mueller, 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; Peterson, G; Philips, S A; Pivnyuk, N; Pocanic, D; Pogorelko, O; 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; Sabatié, F; Sabourov, K; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Shafi, A; Sharabian, Y G; Shaw, J; Simionatto, S; Skabelin, A V; Smith, E S; Smith, L C; Sober, D I; Spraker, M; Stavinsky, A; 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

    2004-02-01

    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. Calculations by Sargsian and by Laget also indicate that we have measured distorted two-nucleon momentum distributions by striking one nucleon and detecting the spectator correlated pair. PMID:14995301

  2. Diversity of fragment sizes in multifragmentation of gold nuclei induced by relativistic {sup 3}He ions

    Energy Technology Data Exchange (ETDEWEB)

    Brzychczyk, J.; Pollacco, E.C.; Volant, C.; Legrain, R. [DAPNIA/SPhN CEA/Saclay, F-91191 Gif-sur-Yvette Cedex (France); Lacroix, D. [GANIL, BP5027 F-14021 Caen Cedex (France); Kwiatkowski, K.; Bracken, D.S.; Morley, K.B.; Renshaw Foxford, E.; Viola, V.E.; Yoder, N.R. [Departments of Chemistry and Physics and Indiana University Cyclotron Facility, Indiana University, Bloomington, Indiana 47405 (United States); Cugnon, J. [Universite de Liege, Institut de Physique, B-4000 Liege 1 (Belgium); Korteling, R.G. [Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, (Canada) V5A S16; Breuer, H. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)

    1998-09-01

    The charge-moment technique has been used to study the fragment charge distribution for the {sup 3}He(4.8thinspGeV)+{sup 197}Au reaction. A large variety of fragment charges characterized by a relative variance {approximately}2.3, is observed for excitation energies around 5.5 MeV/nucleon. Similar signals related to a phase transition are predicted by the percolation model and the statistical multifragmentation model. Effects of detector acceptance and contribution from fission are discussed. {copyright} {ital 1998} {ital The American Physical Society}

  3. Diversity of fragment sizes in multifragmentation of gold nuclei induced by relativistic 3He ions

    International Nuclear Information System (INIS)

    The charge-moment technique has been used to study the fragment charge distribution for the 3He(4.8thinspGeV)+197Au reaction. A large variety of fragment charges characterized by a relative variance ∼2.3, is observed for excitation energies around 5.5 MeV/nucleon. Similar signals related to a phase transition are predicted by the percolation model and the statistical multifragmentation model. Effects of detector acceptance and contribution from fission are discussed. copyright 1998 The American Physical Society

  4. Charge symmetry breaking effect for 3H and 3He within s-wave approach

    Science.gov (United States)

    Filikhin, I.; Suslov, V. M.; Vlahovic, B.

    2016-06-01

    Three-nucleon systems are considered assuming the neutrons and protons to be distinguishable particles. The configuration space Faddeev equations are exploited to calculate ground state energies of 3H and 3He nuclei within an s-wave approach applying the Malfliet-Tjon, Tamagaki G3RS and Afnan-Tang ATS3 NN potentials. We modify the potentials by scaling strength parameters to define nn, pp and np singlet components. The scaling parameters are fixed to reproduce experimental scattering lengths. The charge symmetry breaking energy is numerically evaluated. The relation between nn, pp and np singlet potentials is discussed.

  5. Evidence for soft vortex cores in 3He-B at high magnetic fields

    International Nuclear Information System (INIS)

    Negative ion mobility in rotating 3He-B at magnetic fields H ≅ 0.1 T has been measured along the common direction of H and the rotation axis Ω. When Ω > 0, we observed an increase of mobility, which originates from a reorientation of the anisotropic energy gap. The increase can be understood quantitatively only if soft vortex cores, predicted by Sonin, are assumed. Their size was found to be on the order of the magnetic Healing length ξH

  6. 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.

  7. Investigation of the exclusive 3He(e,e' pn)1H reaction.

    Science.gov (United States)

    Middleton, D G; Annand, J R M; Antelo, M Ases; Ayerbe, C; Barneo, P; Baumann, D; Bermuth, J; Bernauer, J; Blok, H P; Böhm, R; Bosnar, D; Ding, M; Distler, M O; Friedrich, J; Llongo, J García; Glazier, D I; Golak, J; Glöckle, W; Grabmayr, P; Hehl, T; Heim, J; Hesselink, W H A; Jans, E; Kamada, H; Mañas, G Jover; Kohl, M; Lapikás, L; MacGregor, I J D; Martin, I; McGeorge, J C; Merkel, H; Merle, P; Monstad, K; Moschini, F; Müller, U; Nogga, A; Pérez-Benito, R; Pospischil, Th; Potokar, M; Rosner, G; Seimetz, M; Skibiński, R; de Vries, H; Walcher, Th; Watts, D P; Weinriefer, M; Weiss, M; Witała, H; Zihlmann, B

    2009-10-01

    Cross sections for the 3He(e,e' pn)1H reaction were measured for the first time at energy transfers of 220 and 270 MeV for several momentum transfers ranging from 300 to 450 MeV/c. Cross sections are presented as a function of the momentum of the recoil proton and the momentum transfer. Continuum Faddeev calculations using the Argonne V18 and Bonn-B nucleon-nucleon potentials overestimate the measured cross sections by a factor 5 at low recoil proton momentum with the discrepancy becoming smaller at higher recoil proton momentum. PMID:19905628

  8. Investigation of the Exclusive ^{3}He(e,e'pn)p Reaction

    CERN Document Server

    Middleton, D G; Antelo, M Ases; Ayerbe, C; Barneo, P; Baumann, D; Bermuth, J; Bernauer, J; Blok, H P; Bosnar, D; Böhm, R; Ding, M; Distler, M O; Friedrich, J; Llongo, J García; Glazier, D I; Golak, J; Glöckle, W; Grabmayr, P; Hehl, T; Heim, J; Hesselink, W H A; Jans, E; Kamada, H; Mañas, G Jover; Köhl, M; Lapikás, L; MacGregor, I J D; Martin, I; McGeorge, J C; Merkel, H; Merle, P; Monstad, K; Moschini, F; Müller, U; Nogga, A; Benito, R Pérez; Pospischil, Th; Potokar, M; Rosner, G; Seimetz, M; Skibiński, R; De Vries, H; Walcher, Th; Watts, D P; Weinriefer, M; Weiss, M; Witała, H; Zihlmann, B

    2009-01-01

    Cross sections for the ^{3}He(e,e'pn)p reaction were measured for the first time at energy transfers of 220 and 270 MeV for several momentum transfers ranging from 300 to 450 MeV/c. Cross sections are presented as a function of the momentum of the recoil proton and the momentum transfer. Continuum Faddeev calculations using the Argonne V18 and Bonn-B nucleon-nucleon potentials overestimate the measured cross sections by a factor 5 at low recoil proton momentum with the discrepancy becoming much smaller at higher recoil momentum.

  9. Lowest vibrational states of 4He3He+: Non-Born-Oppenheimer calculations

    International Nuclear Information System (INIS)

    Very accurate quantum mechanical calculations of the first five vibrational states of the 4He3He+ molecular ion are reported. The calculations have been performed explicitly including the coupling of the electronic and nuclear motions [i.e., without assuming the Born-Oppenheimer (BO) approximation]. The nonrelativistic non-BO wave functions were used to calculate the α2 relativistic mass velocity, Darwin, and spin-spin interaction corrections. For the lowest vibrational transition, whose experimental energy is established with high precision, the calculated and the experimental results differ by only 0.16 cm-1

  10. 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.

  11. 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.

  12. 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.

  13. The 6Li(e,e'p) and 142,146Nd(e,e'p) reactions

    International Nuclear Information System (INIS)

    In this thesis two special cases of the (e,e'p) reaction are discussed. The first case is a (e,e'p) reaction for which the residual nucleus is unbound. With an unbound residual nucleus in the (e,e'p) reaction the proton-separation energy equals the two-body emission threshold of the target nucleus. Hence such a reaction is very interesting in a study of possible contributions of many-body mechanisms to cross sections obtained in (e,e'p) reactions. These contributions have been studied for the 6Li(e,e'p) reaction. The second case is an investigation of the change in shape of momentum distributions in the (e,e'p) reaction due to deformation effects, by studying proton knockout from 142Nd (spherical in the ground state) and 146N (deformable). The first part of the thesis deals with the 6Li(e,e'p) reaction. First the essential ingredients for the interpretation of the (e,e'p) cross sections are discussed. Three theoretical models, which predict the 6Li(e,e'p) spectral function, are discussed: the harmonic oscillator model shell, a three-body α-n-p cluster model, and another cluster model with different clusterization of the constituents 6Li and 5He. The experimental spectral function is presented and discussed within the theoretical framework. The occurence of reaction mechanisms beyond the quasi-elastic (e,e'p) reaction is investigated. In the second part the 142Ne(e,e'p) an 146Ne(e,e'p) reactions are discussed. The shape of the momentum distribution in deformed nuclei is discussed within the Nilsson model, followed by a summary of the experimental conditions under which the experimental spectral functions of both (e,e'p) reactions have been obtained. The energy-position and momentum distribution of the lowest discrete transitions are compared to the Nilsson-model predictions. (H.W.). 181 p.; 61 figs.; 27 tabs

  14. {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)

  15. Double antikaonic nuclear clusters in antiproton-{sup 3}He annihilation at J-PARC

    Energy Technology Data Exchange (ETDEWEB)

    Sakuma, Fuminori, E-mail: sakuma@ribf.riken.jp [RIKEN, RIKEN Nishina Center (Japan); Curceanu, Catalina [Laboratori Nazionali di Frascati dell' INFN (Italy); Iwasaki, Masahiko [RIKEN, RIKEN Nishina Center (Japan); Kienle, Paul [Technische Universiat Munchen (Germany); Ohnishi, Hiroaki [RIKEN, RIKEN Nishina Center (Japan); Tokuda, Makoto [The University of Tokyo, Department of Physics (Japan); Tsukada, Kyo [Tohoku University, Department of Physics (Japan); Widmann, Eberhard [Stefan-Meyer-Institut fuer Subatomare Physik (Austria); Yamazaki, Toshimitsu [RIKEN, RIKEN Nishina Center (Japan); Zmeskal, Johannes [Stefan-Meyer-Institut fuer Subatomare Physik (Austria)

    2012-12-15

    We search for double anti-kaon nuclear bound states in the p-bar annihilation reaction in {sup 3}He nuclei at rest. In view of the strongly attractive K-bar N interaction, the existence of nuclear clusters with more than one K{sup }- has been predicted theoretically. The double anti-kaon production in elementary antiproton annihilation at rest is forbidden because of the negative Q-value; however, a double anti-kaon nuclear bound state, such as K{sup }- K{sup }- pp, with deep binding energy would enable double anti-kaon production in the nuclei. In order to investigate the K{sup }- K{sup }- pp production in the p-bar + {sup 3}He {yields} K{sup +} + K{sup 0} + X (X = K{sup -} K{sup -} pp) channel, the produced K{sup }- K{sup }- pp cluster is identified both using missing mass spectroscopy via the K{sup + }K{sup 0} channel with a {Lambda}-tag, and invariant mass analysis of the expected decay particles from the K{sup }- K{sup }- pp cluster such as {Lambda}{Lambda}. We propose to perform the experiment at the existing K1.8BR beam line at J-PARC with the E15 spectrometer.

  16. The nuclear reaction n + 3He -> 1H + 3H as proximity reaction

    International Nuclear Information System (INIS)

    The present thesis tries to give by means of the nuclear reaction n + 3He -> 1H + 3H as proximity reaction on the three-particle system 3He + 9Be -> 1H + 3H + 8Be an experimental verification to the second term of a multiple scattering series. The study of these rescattering effects is of great interest for the present theory of the final-state interaction. At three incident energies (7.08 MeV, 8.98 MeV, and 6.37 MeV) to detector telescopes identify the exit channel of the three-particle system in list-mode coincidence experiments according to protons and tritons. Peaks on the kinematical curves occur. The detailed study of their kinematic behaviour allows to exclude the inconcurrence to the proximity reaction lying cascade decays via intermediate states in 4He, 9B, and 11B. Regarding the Coulomb interaction the experimental results can be also explained in the sense of the classical kinematics by the proximity model. (orig.)

  17. Study of anti-deuterons, anti-tritons and anti-{sup 3}He at Belle

    Energy Technology Data Exchange (ETDEWEB)

    Kuenze, Stephanie; Galuska, Martin; Gessler, Thomas; Kuehn, Wolfgang; Lange, Jens Soeren; Muenchow, David; Semmler, Diego; Spruck, Bjoern; Ullrich, Matthias; Werner, Marcel [2. Physikalisches Institut, Universitaet Giessen (Germany)

    2010-07-01

    Events of the type e{sup +}e{sup -}{yields} anti d+X, anti t+X, anti-{sup 3}He+X, are rare events in e{sup +}e{sup -} collisions as they require the production of several anti-quarks together with their corresponding quarks (6+6 in the deuteron case, 9+9 for triton and {sup 3}He). In addition, in order to form a bound state, the anti-quarks must be close in phasespace, so that coalescence (i.e. overlap of the wave functions) can be applied. Preliminary results from Belle at {radical}(s){approx_equal}10.6 GeV with a data set of 589fb{sup -1}, using dE/dx in the Belle drift chamber for particle identification, are presented. The momentum distribution of the anti-nuclei can be compared to a fireball model. Preliminary results of the search for anti-{sup 4}He are also presented.

  18. Vortices with half-integer number of circulation quanta in superfluid 3He-A

    International Nuclear Information System (INIS)

    A method is proposed for the experimental observation of the exotic vortices with a half-integer number of superfluid velocity circulation quanta in rotating 3He-A. The existence of such vortices in 3He-A is possible due to the presence of discrete combined symmetry (gauge transformation+spin rotation). This symmetry couples in a nontrivial manner the superfluid and magnetic properties of the liquid and gives rise to the hybrid of the vortex and disclination in the field of the magnetic anisotropy vector. In a free geometry such vortices are energetically not advantageous due to the spin-orbit (dipole) energy since they are termination lines of the topological solitons. For a parallel-plane geometry with distances between the planes which are smaller than the dipole lenght and in the presence of a sufficiently strong magnetic field normal to the plates the dipole energy is neutralized, and the vortices with half-integer circulation may compete successfully with other types of vortices. Vortices with a half-integer number of quanta should lead to a characteristic behaviour of the NMR signal, and on this basis they may distinguished from singular vortices with a single circulation quantum and from nonsingular vortices with two quanta

  19. Textures of Superfluid 3He-B in Applied Flow and Comparison with Hydrostatic Theory

    CERN Document Server

    de Graaf, R; Hosio, J J; Heikkinen, P J; Krusius, M

    2011-01-01

    Measurements of the order parameter texture of rotating superfluid 3He-B have been performed as a function of the applied azimuthal counterflow velocity down to temperatures of 0.2Tc. The results are compared to the hydrostatic theory of 3He-B. Good agreement is found at all measured temperatures and rotation velocities when the flow anisotropy contribution to the textural free energy is adjusted. This gives a superfluid energy gap Delta(T) which agrees with that measured by Todoshchenko et al., with Delta(0)=1.97kBTc at 29.0 bar. The B-phase susceptibility, longitudinal resonance frequency, and textural phase transition have been extracted from the measurements as a function of temperature and azimuthal counterflow velocity. Owing to decreasing absorption intensities the present measuring method, based on the line shape analysis of the NMR spectrum, loses its sensitivity with decreasing temperature. However, we find that in practice the measurement of vortex numbers and counterflow velocities is still feasib...

  20. The 31P(3He,d)32S reactions at 25MeV

    International Nuclear Information System (INIS)

    The 31P(3He,d)32S reaction was investigated at 25 MeV incident energy. One hundred and eleven levels up to an excitation energy of 12.5 MeV were observed using a split-pole magnetic spectrograph. The experimental angular distributions were analyzed with the distorted-wave Born approximation. The optical model parameters used in the DWBA calculations were obtained from a fit to elastic 3He scattering data taken on 31P at 25 MeV. Gamov functions were used as form factors for the transfered proton in the case of unbound states. Values of the transfered orbital angular momenta l and spectroscopic strengths were obtained for sixty levels, with many odd-parity levels being observed above 9 MeV excitation. Spin and parity assignments were made upon the basis of the l-values obtained from the shapes of the angular distributions and upon comparison with the results of other reactions. Isospin assignments were made by comparison with 32P levels. Except for the lsub(P)=1, T=0 transfers, most of the observed spectroscopic strength is concentrated into a few levels. The existence of a T-mixed doublet of levels, Jsup(π)=1-, is suggested in the 11 MeV region of excitation. The excitation energies and spectroscopic strengths are compared with results of a recent shell-model calculation

  1. Light Higgs channel of the resonant decay of magnon condensate in superfluid 3He-B

    Science.gov (United States)

    Zavjalov, V. V.; Autti, S.; Eltsov, V. B.; Heikkinen, P. J.; Volovik, G. E.

    2016-01-01

    In superfluids the order parameter, which describes spontaneous symmetry breaking, is an analogue of the Higgs field in the Standard Model of particle physics. Oscillations of the field amplitude are massive Higgs bosons, while oscillations of the orientation are massless Nambu-Goldstone bosons. The 125 GeV Higgs boson, discovered at Large Hadron Collider, is light compared with electroweak energy scale. Here, we show that such light Higgs exists in superfluid 3He-B, where one of three Nambu-Goldstone spin-wave modes acquires small mass due to the spin–orbit interaction. Other modes become optical and acoustic magnons. We observe parametric decay of Bose-Einstein condensate of optical magnons to light Higgs modes and decay of optical to acoustic magnons. Formation of a light Higgs from a Nambu-Goldstone mode observed in 3He-B opens a possibility that such scenario can be realized in other systems, where violation of some hidden symmetry is possible, including the Standard Model. PMID:26743951

  2. (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.

  3. Light Higgs channel of the resonant decay of magnon condensate in superfluid (3)He-B.

    Science.gov (United States)

    Zavjalov, V V; Autti, S; Eltsov, V B; Heikkinen, P J; Volovik, G E

    2016-01-01

    In superfluids the order parameter, which describes spontaneous symmetry breaking, is an analogue of the Higgs field in the Standard Model of particle physics. Oscillations of the field amplitude are massive Higgs bosons, while oscillations of the orientation are massless Nambu-Goldstone bosons. The 125 GeV Higgs boson, discovered at Large Hadron Collider, is light compared with electroweak energy scale. Here, we show that such light Higgs exists in superfluid (3)He-B, where one of three Nambu-Goldstone spin-wave modes acquires small mass due to the spin-orbit interaction. Other modes become optical and acoustic magnons. We observe parametric decay of Bose-Einstein condensate of optical magnons to light Higgs modes and decay of optical to acoustic magnons. Formation of a light Higgs from a Nambu-Goldstone mode observed in (3)He-B opens a possibility that such scenario can be realized in other systems, where violation of some hidden symmetry is possible, including the Standard Model. PMID:26743951

  4. 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.

  5. 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)

  6. 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.

  7. 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.

  8. Validity test of the Trojan Horse Method applied to the {sup 7}Li+p{yields} {alpha}+{alpha} reaction via the {sup 3}He break-up

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spitaleri, C.; Sergi, M.L.; Cherubini, S.; La Cognata, M.; Lamia, L.; Romano, S.; Tudisco, S. [Universita di Catania, Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Catania (Italy); INFN Laboratori Nazionali del Sud, Catania (Italy); Kroha, V.; Burjan, V.; Novac, J.; Vincour, J. [Nuclear Physics Institute of ASCR, Rez, Prague (Czech Republic); Fueloep, Z.; Somorjai, E. [Institute of Nuclear Research of Hungarian Academy of Sciences (ATOMKI), Debrecen (Hungary); Pizzone, R.G. [INFN Laboratori Nazionali del Sud, Catania (Italy)

    2006-03-15

    The Trojan Horse Method (THM) was applied to the {sup 3}He+{sup 7}Li interaction in order to investigate the quasi-free {sup 7}Li(p,{alpha}){sup 4}He reaction. The three-body experiment was performed at 33 MeV corresponding to a {sup 7}Li-p relative energy ranging from 50 keV to 7 MeV. The extracted {sup 7}Li(p,{alpha}){sup 4}He quasi-free cross-section was compared with the behavior of direct data, as well as with the result of a previous THM investigation on the {sup 7}Li(p,{alpha}){sup 4}He reaction off the neutron in {sup 2}H. A good agreement between data sets shows up throughout the energy range investigated, providing a very important validity test of the pole approximation for the THM. (orig.)

  9. 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.

  10. 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...

  11. Fast neutron response of {sup 6}Li-depleted CLYC detectors up to 20 MeV

    Energy Technology Data Exchange (ETDEWEB)

    D' Olympia, N., E-mail: nathan_dolympia@student.uml.edu; Chowdhury, P.; Jackson, E.G.; Lister, C.J.

    2014-11-01

    The response of {sup 6}Li-depleted Cs{sub 2}LiYCl{sub 6} (CLYC) to high-energy neutrons has been investigated using a pair of 1 in.×1 in. crystals. These are the first two detectors of their kind, which will comprise a 16-element array for studies in fast neutron spectroscopy. Their thermal neutron response has been compared with standard CLYC crystals with a {sup 6}Li enrichment of 95%, demonstrating excellent suppression of the overwhelming thermal neutron background. The response to mono-energetic neutrons over a range of 0.5 to 20 MeV was tested. From this, the response function, energy resolution, and pulse-shape discrimination up to 20 MeV were characterized. Detailed Monte Carlo investigations with MCNPX have been used to show that the dominant reaction mechanisms contributing to the observed response are {sup 35}Cl(n,p) and {sup 35}Cl(n,α). Preliminary investigations have also demonstrated the possibility for separating events from these two reactions.

  12. 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.

  13. 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.

  14. Reaction mechanism and characteristics of T_{20} in d + ^3He backward elastic scattering at intermediate energies

    OpenAIRE

    Tanifuji, M.; Ishikawa, S.; 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.

    1999-01-01

    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 impor...

  15. Oblique ion acoustic wave instabilities in a multi-ion plasma and 3He-rich events

    International Nuclear Information System (INIS)

    Oblique ion acoustic waves in a current-carrying, magnetized plasma are investigated. For a multi-ion plasma whose dominant components are hydrogen and helium, it is found that for some plasma parameters oblique ion acoustic waves can have positive growth rates at frequencies ω ≅ Ω3He (3He cyclotron frequency) and, at the same time, negative growth rates at ω ≅ Ω4He, It is then suggested that these waves can play an essential role in the 3He-rich solar flares. (author)

  16. 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.

  17. 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.

  18. 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.

  19. A two-stage 3He- 4He fridge for bolometric photometry

    Science.gov (United States)

    Maiani, T.; de Bernardis, P.; De Petris, M.; Granata, S.; Masi, S.; Orlando, A.; Aquilini, E.; Cardoni, P.; Martinis, L.; Scaramuzzi, F.

    1999-09-01

    We describe the design, construction and performance of a double stage 3He- 4He refrigerator, built to cool down a multiband bolometric photometer at the MITO telescope. The fridge was optimized to work without external pumps, with the main cryostat providing a 4.2 K thermostat at sea level and a 4.0 K one at high mountain pressure conditions. The measured ultimate temperature of the fridge is 290 mK, with a hold time of 81 h. The external heat input on the cold flange is ˜35 μW, with the main bath at 4.0 K. The recycle time is 8 h with a heat input on the thermostat during recycling of ˜6800 J. The cryostat can operate without any relevant changes to performance tilted down to 50° from the vertical position, as needed at the telescope focal plane.

  20. The ( sup 3 He,t) reaction at intermediate energies; Spin-isospin multipole transitions

    Energy Technology Data Exchange (ETDEWEB)

    Brockstedt, A.; Bergquist, I.; Carlen, L.; Ekstroem, L.P.; Jakobsson, B. (Lund Univ. (Sweden). Inst. of Physics); Ellegaard, C.; Gaarde, C.; Larsen, J.S. (Niels Bohr Inst., Copenhagen (Denmark)); Goodman, C. (Indiana Univ., Bloomington, IN (USA)); Bedjidian, M.; Contardo, D.; Grossiord, J.Y.; Guichard, A.; Pizzi, J.R. (Lyon Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire); Bachelier, D.; Boyard, J.L.; Hennino, T.; Jourdain, J.C.; Roy-Stephan, M. (Institut de Physique Nucleaire, 91 - Orsay (France)); Boivin, M.; Hasegawa, T.; Radvanyi, P. (Laboratoire National Saturne, 91 - Gif-sur-Yvette (France))

    1991-08-01

    Data for the ({sup 3}He, t) reaction at 900 MeV and 2 GeV on the targets {sup 26}Mg, {sup 40}Ca, {sup 48}Ca, {sup 54}Fe, {sup 90}Zr and {sup 208}Pb are presented. A multipole decomposition for the data at 900 MeV has been made and the different distributions have been analysed. From the L=0 cross section the Gamow-Teller strength distributions are extracted and compared with (p, n) data. The L=1 and 2 distributions are analysed in a schematic model which describes the general systematics fairly well. The spectra at 2 GeV and {Theta}=4deg show for all targets a well-developed quasi-elastic peak. The A-dependence of the cross section is analysed in a simple model. (orig.).

  1. 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.

  2. Vortex pairs in rotating 3He-A in a tilted magnetic field

    International Nuclear Information System (INIS)

    We extend our analysis of Seppaaumllaauml-Volovik vortices in rotating 3He-A in a high magnetic field to the configuration where the magnetic field is tilted from the rotation axis. We find that the distance between vortices in a vortex pair decreases as the tilting angle increases from 0 to π/2. While the transverse NMR satellite frequency is quite insensitive to tilting except at lower temperature, the intensity of the resonance increases by almost 30% when theta0 = π/2 compared to that for theta0 = 0 (theta0 is the tilting angle) at T/T/sub c/approx. =0.75. This is quite consistent with the recent experimental result of Seppaaumllaauml et al

  3. 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.

  4. Determination of the nuclear induced electrical conductivity of 3He for magnetohydrodynamic energy conversion

    International Nuclear Information System (INIS)

    This is the final report for a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The continual need for more efficient, high-output energy conversion techniques has renewed interest in nuclear-driven magnetohydrodynamic (MHD) energy conversion. To provide the fundamental knowledge required to evaluate the potential value of this concept, a one-year project aimed at measuring the nuclear-induced electrical conductivity of a 3He/4He gas mixture under thermodynamic conditions consistent with the MHD flow conditions was carried out. The range of bulk gas conditions to be considered were: pressure = 0.1 to 3800 Torr and temperature = 300 to 1500 K. The maximum neutron flux to be considered was 1016/cm2sec. The range of parameters considered surpassed previous experiments in all aspects

  5. 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)

  6. Bilayer Hubbard model for 3He: a cluster dynamical mean-field calculation

    International Nuclear Information System (INIS)

    Inspired by recent experiments on bilayer 3He, we consider a bilayer Hubbard model on a triangular lattice. For appropriate model parameters, we observe a band-selective Mott transition at a critical chemical potential, μc, corresponding to the solidification of the fermions in the first layer. The growth of the effective mass on the metallic side (μ c) is cut off by a first order transition in which the first layer fermions drop out of the Luttinger volume and their spin degrees of freedom become locked in a spin singlet state. These results are obtained from a cluster dynamical mean-field calculation on an eight-site cluster with a quantum Monte Carlo cluster solver.

  7. Boost Effects in the (e,e') Transverse Response of 3He

    Science.gov (United States)

    Tomusiak, Edward; Efros, Victor; Leidemann, Winfried; Orlandini, Giuseppina; Yuan, Luping

    2015-10-01

    In an earlier paper Efros et al. investigated frame dependence in calculations of the transverse (e,e') response function of 3He. These calculations were non-relativistic but did incorporate relativistic corrections in the electromagnetic operators. Those corrections, taken from the work of Ritz et al. are of order M-3 and represent kinematical effects. It was found that in the region of the quasi-elastic peak, with one proviso, frame dependence held to a good approximation up to q = 700 MeV/c. The one proviso was that we not include one of the corrections - the so-called ω-dependent term. Although this term vanishes in one of the frames (the ANB frame) the question arises as to whether or not another correction exists which might nearly restore frame independence. This work investigates the possibility that Boost effects may provide an explanation. We report on our progress in this regard.

  8. Precision Hyperfine Structure of 2;^3P State of ^3He with External Magnetic

    Science.gov (United States)

    Wu, Qixue; Drake, G. W. F.

    2007-06-01

    The theory of the Zeeman effect can be used to extrapolate precise measurements for the fine structure or the hyperfine structure to zero-field strength. In the present work, the hyperfine structure of 2;^3P state of ^3He with external magnetic fields is precisely calculated. The values of the fields for 32 crossings and five anticrossings of the magnetic sublevels are theoretically predicted for magnetic field strengths up to 1 Tesla. The results are compared with experimental work. We include the linear terms, diamagnetic terms, and the 2̂ relativistic correction terms in the Zeeman Hamiltonian. All related matrix elements are calculated with high accuracy by the use of double basis set Hylleraas type variational wave functions[1,2].[1] Z. -C. Yan and G.W.F. Drake, Phys. Rev. A 50, R1980 (1994).[2] Q. Wu and G.W.F. Drake, J. Phys. B 40, 393 (2007).

  9. 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.

  10. Magnetized liquid 3He at finite temperature: A variational calculation approach

    Science.gov (United States)

    Bordbar, Gholam Hossein; Mohammadi Sabet, Mohammad Taghi

    2016-08-01

    Using the spin-dependent (SD) and spin-independent (SI) correlation functions, we have investigated the properties of liquid 3He in the presence of magnetic field at finite temperature. Our calculations have been done using the variational method based on cluster expansion of the energy functional. Our results show that the low field magnetic susceptibility obeys Curie law at high temperatures. This behavior is in a good agreement with the experimental data as well as the molecular field theory results in which the spin dependency has been introduced in correlation function. Reduced susceptibility as a function of temperature as well as reduced temperature has been also investigated, and again we have seen that the spin-dependent correlation function leads to a good agreement with the experimental data. The Landau parameter, F0a, has been calculated, and for this parameter, a value about ‑ 0.75 has been found in the case of spin-spin correlation. In the case of spin-independent correlation function, this value is about ‑ 0.7. Therefore, inclusion of spin dependency in the correlation function leads to a more compatible value of F0a with experimental data. The magnetization and susceptibility of liquid 3He have also been investigated as a function of magnetic field. Our results show a downward curvature in magnetization of system with spin-dependent correlation for all densities and relevant temperatures. A metamagnetic behavior has been observed as a maximum in susceptibility versus magnetic field, when the spin-spin correlation has been considered. This maximum occurs at 45T ≤ B ≤ 100T for all densities and temperatures. This behavior has not been observed in the case of spin-independent correlation function.

  11. Semi-catalyzed deuterium reactors for co-generation of 3He and synfuels (the CoSCD concept)

    International Nuclear Information System (INIS)

    The potential of developing semi-catalyzed deuterium reactors for co-generation of 3He and synthetic fuels is discussed. Such factors as environmental impact, siting, energy basics, and engineering technology are also discussed

  12. Search and discovery: Nobel prize in physics to Lee, Osheroff and Richardson for discovery of superfluidity in {sup 3}He

    Energy Technology Data Exchange (ETDEWEB)

    Lubkin, G.B. [American Institute of Physics, 500 Sunnyside Boulevard, Woodbury, New York 11797 (United States)

    1996-12-01

    A quarter of a century ago three Cornell experimenters found that when they cooled {sup 3}He below 3 mK it had three different superfluid phases and behaved anisotropically. {copyright} {ital 1996 American Institute of Physics.}

  13. Novel and efficient 10B lined tubelet detector as a replacement for 3He neutron proportional counters

    Science.gov (United States)

    Tsorbatzoglou, Kyriakos; McKeag, Robert D.

    2011-10-01

    This paper presents a novel and robust proportional detector which addresses the well publicized shortage of 3He gas by using a 10B 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 3He tube whilst achieving a sensitivity of up to 75% of a 3 atm 3He device. The design and fabrication of the tubelet detector is presented and discussed with test data comparing the new detector to existing 3He and BF 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.

  14. Search and discovery: Nobel prize in physics to Lee, Osheroff and Richardson for discovery of superfluidity in 3He

    International Nuclear Information System (INIS)

    A quarter of a century ago three Cornell experimenters found that when they cooled 3He below 3 mK it had three different superfluid phases and behaved anisotropically. copyright 1996 American Institute of Physics

  15. 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.

  16. 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.

  17. {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)

  18. 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.

  19. Two and three-dimensional segmentation of hyperpolarized 3He magnetic resonance imaging of pulmonary gas distribution

    Science.gov (United States)

    Heydarian, Mohammadreza; Kirby, Miranda; Wheatley, Andrew; Fenster, Aaron; Parraga, Grace

    2012-03-01

    A semi-automated method for generating hyperpolarized helium-3 (3He) measurements of individual slice (2D) or whole lung (3D) gas distribution was developed. 3He MRI functional images were segmented using two-dimensional (2D) and three-dimensional (3D) hierarchical K-means clustering of the 3He MRI signal and in addition a seeded region-growing algorithm was employed for segmentation of the 1H MRI thoracic cavity volume. 3He MRI pulmonary function measurements were generated following two-dimensional landmark-based non-rigid registration of the 3He and 1H pulmonary images. We applied this method to MRI of healthy subjects and subjects with chronic obstructive lung disease (COPD). The results of hierarchical K-means 2D and 3D segmentation were compared to an expert observer's manual segmentation results using linear regression, Pearson correlations and the Dice similarity coefficient. 2D hierarchical K-means segmentation of ventilation volume (VV) and ventilation defect volume (VDV) was strongly and significantly correlated with manual measurements (VV: r=0.98, phierarchical K-means segmentation of VV and VDV was also strongly and significantly correlated with manual measurements (VV: r=0.98, psemi-automated segmentation of 3He MRI gas distribution provides a way to generate novel pulmonary function measurements.

  20. Super enrichment of Fe-group nuclei in solar flares and their association with large 3He enrichments

    International Nuclear Information System (INIS)

    ''Fe''/He ratios at approximately 2 MeV/n have been measured in 60 solar flares and periods of enhanced fluxes during the interval 1972-1976. The observed ditribution of ratios is extremely wide with values ranging from approximately 1 to more than 1000 times the solar abundance ratio. In constrast, most of the CHO/He ratios for the same flares lie within a factor 2 of the observed mean value of 2 x 10-2. While experimental limitations prevent a complete correlation study of Fe-group and 3He abundances, comparison of flares with large Fe enrichments with flares with large 3He enrichments for the period 1969-1976 shows that a 3He-rich flare is also likely to be rich in iron. We feel that the association of 3He and Fe enrichments may be explained by a two-stage process in which a preliminary enrichment of heavy nuclei precedes the preferential acceleration of ambient 3He. Nuclear interactions are ruled out as the principal source of the enriched 3He. (author)

  1. Development of antireflection coatings with a sup 6 LiF/ sup 6 sup 2 Ni multilayer converter for ultracold neutron detectors

    CERN Document Server

    Maier-Komor, P; Bergmaier, A; Dollinger, G; Paul, S; Schott, W

    2002-01-01

    High efficiency detectors for ultracold neutrons (UCN) are needed at the new high flux neutron source, Forschungsreaktor Muenchen II. In the development described, silicon PIN diodes were chosen to detect the alpha-particles or the tritons created in the reaction sup 6 Li(n,alpha)t. The high reflectance of UCN on sup 6 Li with its positive optical potential must be compensated by a material with negative optical potential. The isotope sup 6 sup 2 Ni was chosen for this. To avoid problems due to chemical reactions of Li with humidity, the compound sup 6 LiF was chosen. One hundred and fifty double layers of sup 6 LiF/ sup 6 sup 2 Ni had to be deposited by physical vapor deposition on silicon PIN diodes which had already been coated with 88 nm approx 77 mu g/cm sup 2 of sup 5 sup 8 Ni for reflection of the UCN. The theoretical optimal thickness of the sup 6 sup 2 Ni layers is 3 nm, and that of sup 6 LiF is 6 nm. Since expensive isotopes were involved, a small source-to-substrate distance had to be used, but wit...

  2. Investigation of the Triton Emission Asymmetry in the $^{6}$Li(n, alpha)$^{3}$H Reaction with Polarized Thermal Neutrons

    CERN Document Server

    Gledenov, Yu M; Nesvizhevsky, V V; Petukhov, A K; Sedyshev, P V; Soldner, T; Shulgina, E V; Zimmer, O

    2002-01-01

    An experiment was carried out at the high-intensity polarized cold neutron beam of the PF1B instrument of the ILL reactor, Grenoble, France. As a detector, the 48-section ionization chamber with the ^{6}LiF targets was used. An integral (current) method of the event detection with compensation of the reactor power fluctuation was applied. Special measurement technique was used for minimization and estimation of the possible false effect contribution. A value of the P-odd (sigma_{\\bf n}, {\\bf P}_{\\bf n}) correlation has been obtained: alpha_{PN}=-(7.1\\pn 3.9)\\cdot 10^{-8}. At the base of the cluster model, the most accurate at present day estimation of the weak neutral current constant has been given: f_n \\leq 1.2\\cdot 10^{-7}.

  3. 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.

  4. Complete and incomplete fusion cross sections for 6Li+209Bi reaction in multi-body classical molecular dynamical model

    International Nuclear Information System (INIS)

    Using the multi-body Classical Molecular Dynamics simulation of 6Li+209Bi reaction it is shown that: (i) the breakup of a projectile fragment near the barrier leads to substantial increase in the ICF probabilities; (ii) the expected increase in σCF on relaxation of the rigid-body (RB) constraint on the projectile is compensated by reduction in the flux leading to CF, due to ICF events; (iii) the breakup probability increases with ECM and, for given ECM it also increases as b increases and peaks around some b>0, while cross sections σCF and σTF were calculated for b=0 only Therefore, we present the results of σCF (Complete Fusion) and σTF (Total Fusion) calculations which are obtained at critical impact parameter, bcr, where many ICF channels open up and compare with the calculations performed at b=0 only, where only few ICF channels open up

  5. 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.

  6. 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.

  7. Kinematically complete measurements of the break-up of 6Li using the magnetic spectrograph 'Little John'

    International Nuclear Information System (INIS)

    This report describes set-up and application of an extended detection system for the magnetic spectrograph 'Little John'. The set-up is used in experiments of the Coulomb induced break-up of 6Li into α-particles and deuterons at the Karlsruhe Isochronous Cyclotron for the detection of both coincidence fragments. In first measurements the properties of the detection system are explored. It is shown that the extension provides an increased efficiency, simultaneously maintaining the angular resolution. This is achieved by a direct measurement of both particle trajectories and by an off-line subdivision of the solid angle acceptance. The differential cross sections obtained in this way are in a good agreement with known results and are completing the experimental information. (orig.)

  8. Hyperpolarised {sup 3}He MRI and {sup 81m}Kr SPECT in chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Stavngaard, Trine [Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet (Denmark); Copenhagen University Hospital, Danish Research Centre for Magnetic Resonance, Hvidovre (Denmark); Soegaard, Lise Vejby; Hanson, Lars G. [Copenhagen University Hospital, Danish Research Centre for Magnetic Resonance, Hvidovre (Denmark); Mortensen, Jann; Berthelsen, Anne Kiil [Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet (Denmark); Schmiedeskamp, Joerg [Johannes Gutenberg Universitaet, Institut fuer Physik, Mainz (Germany); Dirksen, Asger [Gentofte University Hospital, Department of Respiratory Medicine, Hellerup (Denmark)

    2005-04-01

    During recent years, magnetic resonance imaging (MRI) using hyperpolarised (HP) {sup 3}He gas has emerged as a promising new method for the imaging of lung ventilation. However, systematic comparisons with nuclear medicine techniques have not yet been performed. The aim of this study was to compare ventilation imaging methods in 26 patients with chronic obstructive pulmonary disease (COPD) and nine lung healthy volunteers. HP {sup 3}He MRI, {sup 81m}Kr single-photon emission computed tomography (SPECT), high-resolution computed tomography (HRCT) and pulmonary function tests were performed. The three scans were scored visually as percentage of non-ventilated/diseased lung, and a computer-based objective measure of the ventilated volume in HP {sup 3}He MRI and {sup 81m}Kr SPECT and an emphysema index in HRCT were calculated. We found a good correlation between HP {sup 3}He MRI and {sup 81m}Kr SPECT for both visual defect score (r=0.80, p<0.0001) and objective estimate of ventilation (r=0.45, p=0.0157). In addition, both scans were well correlated with reference methods for the diagnosis of emphysema (pulmonary function test and HRCT). The defect scores were largest on {sup 81m}Kr SPECT (the score on HP {sup 3}He MRI was one-third less than that on {sup 81m}Kr SPECT), but the difference was reduced after normalisation for different breathing depths (HP {sup 3}He MRI at total lung capacity; {sup 81m}Kr SPECT at tidal breathing at functional residual capacity). HP {sup 3}He MRI provides detailed ventilation distribution images and defect scores are comparable on HP {sup 3}He MRI and {sup 81m}Kr SPECT. Additionally, new insights into the regional pulmonary microstructure via the apparent diffusion coefficient measurements are provided by HP {sup 3}He MRI. HP {sup 3}He MRI is a promising new diagnostic tool for the assessment of ventilation distribution. (orig.)

  9. 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

  10. 3He lung morphometry technique: Accuracy analysis and pulse sequence optimization

    Science.gov (United States)

    Sukstanskii, A. L.; Conradi, M. S.; Yablonskiy, D. A.

    2010-12-01

    The 3He lung morphometry technique (Yablonskiy et al., JAP, 2009), based on MRI measurements of hyperpolarized gas diffusion in lung airspaces, provides unique information on the lung microstructure at the alveolar level. 3D tomographic images of standard morphological parameters (mean airspace chord length, lung parenchyma surface-to-volume ratio, and the number of alveoli per unit lung volume) can be created from a rather short (several seconds) MRI scan. These parameters are most commonly used to characterize lung morphometry but were not previously available from in vivo studies. A background of the 3He lung morphometry technique is based on a previously proposed model of lung acinar airways, treated as cylindrical passages of external radius R covered by alveolar sleeves of depth h, and on a theory of gas diffusion in these airways. The initial works approximated the acinar airways as very long cylinders, all with the same R and h. The present work aims at analyzing effects of realistic acinar airway structures, incorporating airway branching, physiological airway lengths, a physiological ratio of airway ducts and sacs, and distributions of R and h. By means of Monte-Carlo computer simulations, we demonstrate that our technique allows rather accurate measurements of geometrical and morphological parameters of acinar airways. In particular, the accuracy of determining one of the most important physiological parameter of lung parenchyma - surface-to-volume ratio - does not exceed several percent. Second, we analyze the effect of the susceptibility induced inhomogeneous magnetic field on the parameter estimate and demonstrate that this effect is rather negligible at B0 ⩽ 3T and becomes substantial only at higher B0 Third, we theoretically derive an optimal choice of MR pulse sequence parameters, which should be used to acquire a series of diffusion-attenuated MR signals, allowing a substantial decrease in the acquisition time and improvement in accuracy of the

  11. 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...

  12. Non-intrusive measurement of tritium activity in waste drums by modelling a 3He leak quantified by mass spectrometry

    International Nuclear Information System (INIS)

    This study deals with a new method that makes it possible to measure very low tritium quantities inside radioactive waste drums. This indirect method is based on measuring the decaying product, 3He, and requires a study of its behaviour inside the drum. Our model considers 3He as totally free and its leak through the polymeric joint of the drum as two distinct phenomena: permeation and laminar flow. The numerical simulations show that a pseudo-stationary state takes place. Thus, the 3He leak corresponds to the tritium activity inside the drum but it appears, however, that the leak peaks when the atmospheric pressure variations induce an overpressure in the drum. Nevertheless, the confinement of a drum in a tight chamber makes it possible to quantify the 3He leak. This is a non-intrusive measurement of its activity, which was experimentally checked by using reduced models, representing the drum and its confinement chamber. The drum's confinement was optimised to obtain a reproducible 3He leak measurement. The gaseous samples taken from the chamber were purified using selective adsorption onto activated charcoals at 77 K to remove the tritium and pre-concentrate the 3He. The samples were measured using a leak detector mass spectrometer. The adaptation of the signal acquisition and the optimisation of the analysis parameters made it possible to reach the stability of the external calibrations using standard gases with a 3He detection limit of 0.05 ppb. Repeated confinement of the reference drums demonstrated the accuracy of this method. The uncertainty of this non-intrusive measurement of the tritium activity in 200-liter drums is 15% and the detection limit is about 1 GBq after a 24 h confinement. These results led to the definition of an automated tool able to systematically measure the tritium activity of all storage waste drums. (authors)

  13. 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.).

  14. Parametric excitation of the J=2+ modes by zero sound in superfluid 3He-B

    International Nuclear Information System (INIS)

    We discuss order-parameter collective modes in weakly inhomogeneous states of superfluid 3He-B, i.e., states in which the scale of the inhomogeneities is considerably longer than the coherence length ξ0=vt/2πTc and the energy associated with the inhomogeneity is small compared to the condensation energy. The theory describes resonance phenomena between order-parameter modes and zero sound. We discuss two specific cases, both of which involve excitation of the J=2+ modes via a parametric field that lifts the selection rule due to particle-hole symmetry. In the case of a static superflow the modes with J=2+, M=±1 couple to sound for qparallelH, and should be observable as Zeeman states with a maximum absorption that scales as the square of the superflow velocity. The J=2+ modes may also be excited parametrically in a three-wave resonance process involving two zero-sound phonons. We summarize the nonlinear response theory for two-phonon excitation of these modes. (orig.)

  15. Search for Solar Axions Produced in the $p + d \\rightarrow\\rm{^3He}+ A$ Reaction

    CERN Document Server

    Derbin, A V; Muratova, V N; 10.3103/S106287381006016X

    2010-01-01

    A search for the axioelectric absorption of 5.5-MeV solar axions produced in the $p+d\\rightarrow \\rm{^3He}+\\gamma(5.5 \\rm{MeV})$ reaction was performed with two BGO detectors placed inside a low-background setup. A model independent limit on axion-photon and axion-nucleon couplings was obtained: $|g_{Ae}\\times g_{AN}| \\leq 3.2\\times 10^{-9} (m_A=0)$. Constraints on the axion-electron coupling constant were obtained for axions with masses in the $(0.1-1.0)$ MeV range: $g_{Ae}\\leq (1.8-9.0)\\times 10^{-7}$. The solar positron flux from $A\\rightarrow e^-+e^+$ decay was determined for axions with masses $m_A > 2m_e$. Using the existing experimental data on the interplanetary positron flux, a new constraint on the axion-electron coupling constant for axions with masses in the $(1.2-5.4)$ MeV range was obtained: $g_{Ae} \\leq (1-5)\\times 10^{-17}$.

  16. 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.

  17. 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.

  18. 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.

  19. 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...

  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. Dispersion induced splitting of the collective mode spectrum in A-phase of superfluid 3He

    International Nuclear Information System (INIS)

    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-parallel l only. For any other directions there is a three-fold splitting of these modes, which reaches maximum for k-perpendicular 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.

  2. NMR Properties of the Polar Phase of Superfluid ^3He in Anisotropic Aerogel Under Rotation

    Science.gov (United States)

    Mineev, V. P.

    2016-09-01

    The polar phase of superfluid ^3He is stable in "nematically ordered" densed aerogel. A rotating vessel with the polar superfluid can be filled either by an array of the single quantum vortices or by an array of the half-quantum vortices. It is shown that the inhomogeneous distribution of the spin part of the order parameter arising in an array of half-quantum vortices in strong enough magnetic field tilted to the average direction of aerogel strands leads to the appearance of a satellite in the NMR signal shifted in the negative direction with respect to the Larmor frequency. The satellite is absent in the case of an array of single quantum vortices which allows to distinguish these two configurations. The polar state in the anisotropic aerogel with lower density transforms at lower temperatures to the axipolar state. The array of half-quantum vortices created in the polar phase keeps its structure under transition to the axipolar state. The temperature dependence of the vortex-satellite NMR frequency is found to be slower below the transition temperature to the axipolar state.

  3. The 3He long-counter TETRA at the ALTO ISOL facility

    Science.gov (United States)

    Testov, D.; Verney, D.; Roussière, B.; Bettane, J.; Didierjean, F.; Flanagan, K.; Franchoo, S.; Ibrahim, F.; Kuznetsova, E.; Li, R.; Marsh, B.; Matea, I.; Penionzhkevich, Yu.; Pai, H.; Smirnov, V.; Sokol, E.; Stefan, I.; Suzuki, D.; Wilson, J. N.

    2016-04-01

    A new β-decay station (BEDO) has been installed behind the PARRNe mass separator operated on-line at the electron-driven ALTO ISOL facility. The station is equipped with a movable tape collector allowing the creation of the radioactive sources of interest at the very center of a modular detection system. The mechanical structure was designed to host various assemblies of detectors in compact geometry. We report here the first on-line use of this system equipped with the 4π 3He neutron counter TETRA built at JINR Dubna associated with HPGe and plastic 4π β detectors. The single neutron detection efficiency achieved is 53(2)% measured using the 252Cf source. For β-delayed neutron measurements the neutron detection efficiency was derived from the comparison of gated γ-spectra. The on-line commissioning of the TETRA setup was performed with laser-ionized gallium beams. β and neutron events were recorded as a function of time. From these data we report P1n(82Ga)=22(2)% and T1/2(82Ga)=0.604(11) s in good agreement with values available in the literature. The new detection system will be used in other experiments aimed at investigations of β-decay properties of neutron-rich isotopes produced at ALTO.

  4. 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.

  5. Source size and time dependence of multifragmentation induced by GeV {sup 3}He beams

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G.; Kwiatkowski, K.; Bracken, D.S.; Renshaw Foxford, E.; Hsi, W.; Morley, K.B.; Viola, V.E.; Yoder, N.R. [Departments of Chemistry and Physics and IUCF, Indiana University, Bloomington, Indiana 47405 (United States); Volant, C.; Legrain, R.; Pollacco, E.C. [DAPNIA/SPhN, CEA/Saclay, F-91191 Gif-sur-Yvette (France); Korteling, R.G. [Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, (Canada) V5A 156; Friedman, W.A. [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Botvina, A. [INFN and Department of Physics, University of Bologna, 40126 Bologna (Italy); Brzychczyk, J. [Institute of Physics, Jagiellonian University, Krakow (Poland); Breuer, H. [Department of Physics, University of Maryland, College Park, Maryland 20740 (United States)

    1999-07-01

    To investigate the source size and time dependence of multifragmentation reactions, small- and large-angle relative velocity correlations between coincident complex fragments have been measured for the 1.8{endash}4.8 GeV {sup 3}He+{sup nat}Ag, {sup 197}Au systems. The results support an evolutionary scenario for the fragment emission process in which lighter IMFs (Z{approx_lt}6) are emitted from a hot, more dense source prior to breakup of an expanded residue. For the most highly excited residues, for which there is a significant yield of fragments with very soft energy spectra (E/A{le}3 MeV), comparisons with an {ital N}-body simulation suggest a breakup time of {tau}{approximately}50 fm/c for the expanded residue. Comparison of these data with both the evolutionary expanding emitting source model and the Copenhagen statistical multifragmentation model shows good agreement for heavier IMF{close_quote}s formed in the final breakup stage, but only the evolutionary model is successful in accounting for the lighter IMFs. thinsp {copyright} {ital 1999} {ital The American Physical Society}

  6. Source size and time dependence of multifragmentation induced by GeV 3He beams

    International Nuclear Information System (INIS)

    To investigate the source size and time dependence of multifragmentation reactions, small- and large-angle relative velocity correlations between coincident complex fragments have been measured for the 1.8 - 4.8 GeV 3He+natAg, 197Au systems. The results support an evolutionary scenario for the fragment emission process in which lighter IMFs (Z approx-lt 6) are emitted from a hot, more dense source prior to breakup of an expanded residue. For the most highly excited residues, for which there is a significant yield of fragments with very soft energy spectra (E/A≤3 MeV), comparisons with an N-body simulation suggest a breakup time of τ∼50 fm/c for the expanded residue. Comparison of these data with both the evolutionary expanding emitting source model and the Copenhagen statistical multifragmentation model shows good agreement for heavier IMF close-quote s formed in the final breakup stage, but only the evolutionary model is successful in accounting for the lighter IMFs. copyright 1999 The American Physical Society

  7. Source size and time dependence of multifragmentation induced by GeV [sup 3]He beams

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G.; Kwiatkowski, K.; Bracken, D.S.; Renshaw Foxford, E.; Hsi, W.; Morley, K.B.; Viola, V.E.; Yoder, N.R. (Departments of Chemistry and Physics and IUCF, Indiana University, Bloomington, Indiana 47405 (United States)); Volant, C.; Legrain, R.; Pollacco, E.C. (DAPNIA/SPhN, CEA/Saclay, F-91191 Gif-sur-Yvette (France)); Korteling, R.G. (Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, (Canada) V5A 156); Friedman, W.A. (Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)); Botvina, A. (INFN and Department of Physics, University of Bologna, 40126 Bologna (Italy)); Brzychczyk, J. (Institute of Physics, Jagiellonian University, Krakow (Poland)); Breuer, H. (Department of Physics, University of Maryland, College Park, Maryland 20740 (United States))

    1999-07-01

    To investigate the source size and time dependence of multifragmentation reactions, small- and large-angle relative velocity correlations between coincident complex fragments have been measured for the 1.8[endash]4.8 GeV [sup 3]He+[sup nat]Ag, [sup 197]Au systems. The results support an evolutionary scenario for the fragment emission process in which lighter IMFs (Z[approx lt]6) are emitted from a hot, more dense source prior to breakup of an expanded residue. For the most highly excited residues, for which there is a significant yield of fragments with very soft energy spectra (E/A[le]3 MeV), comparisons with an [ital N]-body simulation suggest a breakup time of [tau][approximately]50 fm/c for the expanded residue. Comparison of these data with both the evolutionary expanding emitting source model and the Copenhagen statistical multifragmentation model shows good agreement for heavier IMF[close quote]s formed in the final breakup stage, but only the evolutionary model is successful in accounting for the lighter IMFs. thinsp [copyright] [ital 1999] [ital The American Physical Society

  8. 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...

  9. Spin waves in the B-phase of superfluid 3He in confined cylindrical geometry

    International Nuclear Information System (INIS)

    We describe experiments on superfluid 3He in a cylinder of 1 mm in diameter. This geometry causes the preferred orientation of the n-vector in the superfluid B-phase to be locally different, resulting in a curved configuration across the sample. Exclusive to our experiment is the observation that we succeeded in obtaining a texture which is metastable and unchanged in our pressure and temperature ranges, most likely because the experiment is performed at low pressures and low magnetic fields. As this texture can be considered as a potential for spin waves, we had the unique opportunity to study spin waves for several pressures in exactly the same texture. Our geometry causes this texture potential to be nearly quadratic, allowing an analytic solution of the theory which can be compared to our experimental results. As predicted we find the intensities of all spin wave modes more or less equal. Increasing the pressure shows a gradual increase in the number of spin wave modes in our cell. Finally we were able to cause a transition from the metastable to the predicted stable texture, concluding unexpectedly that the metastable texture is realized if the growing (or cooling) speed is sufficiently slow.

  10. 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%.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Search for 3He and 4He in Arata-Style Palladium Cathodes I: A Negative Result

    International Nuclear Information System (INIS)

    The 3He and 4He concentrations in 2- to 6-mg samples of palladium-black from the interior of Arata-style cathodes were investigated using a tungsten wire furnace on-line to an ultrahigh sensitivity static mass spectrometer. The detection limit of the mass spectrometer was ∼104 atoms 3He and 108 atoms 4He, and the mass resolution of 1 part in 620 was sufficient to cleanly resolve 3He from H3 and HD. Three specimens of palladium-black (A, B, and C) were from hollow Pd cathodes that had generated excess heat in D2O electrolysis experiments carried out by Arata and Zhang in their laboratory. One specimen of Pd-black (D) had not been used in any electrolysis experiment. A total of twelve samples, three from each specimen, were analyzed. The 3He and 4He concentrations were variable as if due to sample inhomogeneity. Two samples (C-1 and B-1) showed apparent 4He of 4.4 x 109 atoms/mg and 6.6 x 109 atoms/mg, respectively, and three (A-3, B-2, and D-3) showed excess 3He from 77 to 1096 x 103 atoms/mg relative to the atmospheric 3He/4He ratio. Seven samples showed no apparent excess of 3He or 4He. Five samples of the aluminum foil used to wrap Pd-black samples were also analyzed and gave mean values of 13 ± 18 x 103 atoms/mg and 1.50 ± 0.66 x 109 atoms/mg for 3He and 4He, respectively. The values for Al and Pd-black are comparable to the 1978 results of Mamyrin, Khabarin, and Yudenich, who examined helium isotopes in many ordinary metals and other materials including Al and Pd. At present, there is no evidence for the very much larger concentrations (1016 to 1017 atoms/mg) of 3He and 4He that Arata and Zhang claim to have detected in similar specimens of Pd-black from Pd cathodes subjected to D2O electrolysis

  16. Emphysema Quantification in Inflation-Fixed Lungs Using Low-Dose Computed Tomography and 3He Magnetic Resonance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gierada, David S.; Woods, Jason C.; Jacob, Rick E.; Bierhals, Andrew J.; Choong, Cliff K.; Bartel, Seth T.; Chang, Yulin V.; Das, Nitin A.; Hong, Cheng; Lutey, Barbara; Ritter, Jon H.; Pilgram, Thomas K.; Cooper, Joel D.; Patterson, G Alexander; Battafarano, Richard J.; Meyers, Bryan F.; Yablonskiy, Dmitriy A.; Conradi, Mark S.

    2010-09-02

    Abstract: Objective: To evaluate the use of inflation-fixed lung tissue for emphysema quantification with CT and 3He MR diffusion imaging. Methods: Fourteen subjects representing a range of chronic obstructive pulmonary disease severity who underwent complete or lobar lung resection were studied. CT measurements of lung attenuation and MR measurements of the hyperpolarized 3He apparent diffusion coefficient (ADC) in resected specimens fixed in inflation with heated formalin vapor were compared with measurements obtained before fixation. Results: The mean CT emphysema index was 56% ± 17% before and 58% ± 19% after fixation (P=0.77;R=0.76). Index differences correlated with differences in lung volume (R2=0.47). The mean 3He ADC was 0.40 ± 0.15 cm2/sec before and 0.39 ± 0.14 cm2/sec after fixation (P=0.03, R=0.98). The CT emphysema index and the 3He ADC were correlated before (R=0.89) and after fixation (R=0.79). Conclusion: Concordance of CT and 3He MR imaging measurements in unfixed and inflation-fixed lungs supports the use of inflation-fixed lungs for quantitative imaging studies in emphysema.

  17. HOTSPUR progress report: neutron source spectrum characterization, and 6Li(n,xα) and 7Li(n,xα) cross section determination

    International Nuclear Information System (INIS)

    As a prerequisite to high accuracy measurements involving the bulk configuration of 6LiD we must have a good grasp of the details of the RTNS-I neutron source energy spectrum. Experiments to this end involving neutron yield vs deuteron energy, ratios of foil activation of selected elements, and pulse height distributions of a Si surface barrier detector are described. With this knowledge, the 4He-production cross sections for 6Li and 7Li are found experimentally to be 0.512b and 0.336b, respectively, at anti E/sub N/ = 15.0 MeV in free-field geometry. 14 references

  18. The non-statistical population of the 11.10 MeV 4+ state in 16O by 12C(6Li, d)

    International Nuclear Information System (INIS)

    When compound nucleus calculations are normalized to the 13.88 MeV 4+12C(6Li,d)16O cross section it is found that the population of the 11.10 MeV 4+ state is underpredicted by a factor of four. These results mean that the anomalous population of the 11.10 MeV 4+ state in 16O by the 12C(6Li,d) reaction is not compound nuclear in origin

  19. Search for the 4He-eta bound state in dd->(4He-eta)_{bound}->3He n pi0 and dd->(4He-eta)_{bound}->3He p pi- reactions with the WASA-at-COSY facility

    CERN Document Server

    Skurzok, M; Moskal, P

    2014-01-01

    In November 2010, the search for the 4He-{\\eta} bound state was per formed with high statistics and high acceptance with the WASA-at-COSY facility using a ramped beam technique. The signature of eta - mesic nuclei is searched for in the measured excitation functions for the two reaction channels: dd ->3He n pi0 and dd ->3He p pi- near the eta production threshold. This report includes the description of the experimental method and the status of the data analysis.

  20. Orientation-Dependent 3He Lung Imaging in an Open Access, Very-Low-Field Human MRI System

    CERN Document Server

    Mair, R W; Patz, S; Rosen, M S; Ruset, I C; Topulos, G P; Tsai, L L; Butler, J P; Hersman, F W; Walsworth, R L

    2004-01-01

    Orientation-dependent imaging of human lungs is demonstrated using inhaled laser-polarized 3He gas and an open-access very-low-magnetic field (< 5 mT) MRI instrument. This prototype device employs a simple, low-cost electromagnet, with an open geometry that allows variation of the orientation of the imaging subject in a two-dimensional plane. Two-dimensional 3He images were acquired with 2 mm in-plane resolution from a subject in two orientations: lying supine, and sitting in a vertical position with one arm raised. The images show clear differences in lung shape and inhaled 3He gas distribution, consistent with the expected orientation dependence of pulmonary physiology.

  1. An experimental study of the reaction p + d → 3He + π0 in the Δ(1236) resonance region

    International Nuclear Information System (INIS)

    The differential cross section of the reaction p + d → 3He + π0 was measured at an incident proton energy of 462 MeV for 3He cm angles between 50 and 1300. Limited angular distributions were also obtained at 377 and 576 MeV. The 3He particle momentum was measured by using wire spark chambers in conjunction with a total energy absorption scintillation counter. A decay photon from the π0 was detected in a lead glass Cherenkov counter. The results are discussed in terms of a two-nucleon model and a OPE model of the reaction. The cross section at 462 MeV is also compared with that of its isospin conjugate reaction, p + d → 3H + π+, and agreement with the principle of isospin invariance is satisfactory, except at small pion angles. (U.S.)

  2. 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.

  3. 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

  4. Geochemical and 3He/ 4He evidence for mantle and crustal contributions to geothermal fluids in the western Canadian continental margin

    Science.gov (United States)

    Clark, I. D.; Phillips, R. J.

    2000-12-01

    Isotopic and geochemical evidence together with helium isotopes are used to identify contributions of deep crustal to upper mantle volatile components in thermal waters at three sites across the western North American plate margin: (1) the low heat-flow forearc of the Cascadia subduction zone; (2) the high heat-flow volcanic arc; and (3) the interior crystalline terrain of the ancestral continental margin. Western continental margin hotsprings issue 50°C, low salinity Na-Cl water and N 2 gas with 0.25% CH 4. Stable isotopes and 14C indicate local meteoric recharge during the early Holocene. Redox is buffered by sulphate reduction, suggesting that the methane originates from a deeper source. The waters have high helium contents (He/He air=30) and a 3He-excess ( R/ Rair=0.27; 3He/ 3Heair=8), representing a mixture of radiogenic 4He production in crystalline rock with >10% He from subducted oceanic crust. Geophysical data indicate fluid-filled discontinuities in the subduction zone that may provide a pathway for He, and possibly for CH 4 and a saline fluid component from depth. In the Garibaldi belt of Quaternary arc-volcanism, 60°C Na-Cl hotsprings and 200°C geothermal well waters discharge from fractures in the basement rocks. δ18O and δ2H show the thermal waters to be a mixture of local recharge with up to 8% "andesitic" water from the upper mantle. He isotopes indicate a mantle origin ( R/ Rair=6.0), with a minor crustal signature, consistent with observations in the Cascadia range to the south and at other circum-Pacific volcanic arc settings. High PCO 2, an enriched δ13C DIC, elevated 3He/CO 2 ratios and elevated Cl - are likely to be derived from subducted Juan de Fuca plate sediments and pore waters. Thermal Na-SO 4 waters (up to 58°C) from the Omineca Crystalline Belt are locally recharged and have an unusually rapid circulation time of less than 40 years. This contrasts with their high radiogenic He content (176×10 -7 cc/g) with minimal mantle input

  5. 3 He Co-magnetometer Readout for the SNS nEDM Experiment

    Science.gov (United States)

    Kim, Young Jin; Clayton, Steven

    2014-09-01

    A search for a permanent electric dipole moment (EDM) of the neutron would provide one of the most important low energy tests of the discrete symmetries beyond the Standard Model of particle physics. A new experimental search of neutron EDM, to be conducted at the Spallation Neutron Source (SNS) at ORNL, has been proposed with a goal of 100-fold improvement in the present experimental limit of 10-26e .cm The experiment is based on the magnetic-resonance technique in which polarized neutrons precess at the Larmor frequency when placed in a static magnetic field; a non-zero EDM would be evident as a difference in precession frequency when a strong electric field is applied parallel vs. anti-parallel to the magnetic field. In addition to its role as neutron spin-analyzer via the spin-dependent n+3He nuclear capture process, polarized helium-3 (which has negligible EDM) will serve as co-magnetometer to correct for drifts in the magnetic field. The helium-3 co-magnetometer will be directly read out by superconducting gradiometers coupled to SQUIDs. We describe a proposed SQUID system suitable for the complex neutron EDM apparatus, and demonstrate that the field noise in the SQUID system, tested in an environment similar to the EDM apparatus, meets the nEDM requirement. We also present a test of the compatibility of low-noise SQUID operation with other devices, potential sources of electromagnetic interference, which are necessarily operating during the EDM measurement period and effective ambient magnetic field noise cancellation with an implementation of reference channels.

  6. 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.

  7. Intercomparison of tritium and noble gases analyses, 3H/3He ages and derived parameters excess air and recharge temperature

    International Nuclear Information System (INIS)

    Highlights: • Key results of the groundwater age-dating interlaboratory comparison exercise. • The reproducibility of the tritium measurements was 13.5%. • The noble gas reproducibility was <2% (R, He, Ne) and <3% (Ar, Kr, Xe). • The measurement uncertainty meets the requirements for 3H/3He dating. • Other sources of uncertainty are less well defined than the analytical uncertainty. - Abstract: Groundwater age dating with the tritium–helium (3H/3He) method has become a powerful tool for hydrogeologists. The uncertainty of the apparent 3H/3He age depends on the analytical precision of the 3H measurement and the uncertainty of the tritiogenic 3He component. The goal of this study, as part of the groundwater age-dating interlaboratory comparison exercise, was to quantify the analytical uncertainty of the 3H and noble gas measurements and to assess whether they meet the requirements for 3H/3He dating and noble gas paleotemperature reconstruction. Samples for the groundwater dating intercomparison exercise were collected on 1 February, 2012, from three previously studied wells in the Paris Basin (France). Fourteen laboratories participated in the intercomparison for tritium analyses and ten laboratories participated in the noble gas intercomparison. Not all laboratories analyzed samples from every borehole. The reproducibility of the tritium measurements was 13.5%. The reproducibility of the 3He/4He ratio and 4He, Ne, Ar, Kr and Xe concentrations was 1.4%, 1.8%, 1.5%, 2.2%, 2.9%, and 2.4% respectively. The uncertainty of the tritium and noble gas measurements results in a typical 3H/3He age precision of better than 2.5 years in this case. However, the measurement uncertainties for the noble gas concentrations are insufficient to distinguish the appropriate excess air model if the measured helium concentration is not included. While the analytical uncertainty introduces an unavoidable source of uncertainty in the 3H/3He apparent age estimate, other sources of

  8. Activation measurement of the 3He(a,g)7Be reaction cross section at high energies

    CERN Document Server

    Bordeanu, C; Halász, Z; Szücs, T; Kiss, G G; Elekes, Z; Farkas, J; Fülöp, Zs; Somorjai, E; 10.1016/j.nuclphysa.2013.03.012

    2013-01-01

    The astrophysically important 3He(a,g)7Be reaction was studied at high energies where the available experimental data are in contradiction. A thin window 3He gas cell was used and the cross section was measured with the activation method. The obtained cross sections at energies between Ec.m. = 1.5 and 2.5 MeV are compared with the available data and theoretical calculations. The present results support the validity of the high energy cross section energy dependence observed by recent experiments.

  9. 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.

  10. 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

  11. 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.

  12. Study of the reactions 9Be(p, α)6Li, 9Be(p,d)8Be from 300 keV to 900 keV

    International Nuclear Information System (INIS)

    The experimental results concerning the two reactions 9Be(p,α)6Li and 9Be(p,d)8Be from 300 to 900 keV are presented. The angular distribution, excitation and total cross-section curves are expressed in absolute values after a normalization carried out using results given by Weber, Davis and Marion. (authors)

  13. Investigating sorption on iron-oxyhydroxide soil minerals by solid-state NMR spectroscopy: a 6Li MAS NMR study of adsorption and absorption on goethite

    DEFF Research Database (Denmark)

    Nielsen, Ulla Gro; Paik, Younkee; Julmis, Keinia;

    2005-01-01

    H, the system representing an ideal model system for NMR studies. 6Li resonances with large hyperfine shifts (approximately 145 ppm) were observed above the goethite point of zero charge, providing clear evidence for the presence of Li-O-Fe connectivities, and thus the formation of an inner sphere Li+ complex...

  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. 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.

  16. Improved neutron-gamma discrimination for a 6Li-glass neutron detector using digital signal analysis methods

    International Nuclear Information System (INIS)

    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

  17. 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.

  18. 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.

  19. 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.

  20. 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).