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179 results on '"Ruprecht, G."'

1. A direct measurement of the 17O(a,g)21Ne reaction in inverse kinematics and its impact on heavy element production

Author

Taggart, M. P., Akers, C., Laird, A. M., Hager, U., Ruiz, C., Hutcheon, D. A., Bentley, M. A., Brown, J. R., Buchmann, L., Chen, A. A., Chen, J., Chipps, K. A., Choplin, A., D'Auria, J. M., Davids, B., Davis, C., Diget, C. Aa., Erikson, L., Fallis, J., Fox, S. P., Frischknecht, U., Fulton, B. R., Galinski, N., Greife, U., Hirschi, R., Howell, D., Martin, L., Mountford, D., Murphy, A. St. J., Ottewell, D., Pignatari, M., Reeve, S., Ruprecht, G., Sjue, S., Veloce, L., and Williams, M.

Subjects
Nuclear Experiment
Abstract

During the slow neutron capture process in massive stars, reactions on light elements can both produce and absorb neutrons thereby influencing the final heavy element abundances. At low metallicities, the high neutron capture rate of 16-O can inhibit s-process nucleosynthesis unless the neutrons are recycled via the 17O(a,n)20Ne reaction. The efficiency of this neutron recycling is determined by competition between the 17O(a,n)20Ne and 17O(a,g)21Ne reactions. While some experimental data are available on the former reaction, no data exist for the radiative capture channel at the relevant astrophysical energies. The 17O(a,g)21Ne reaction has been studied directly using the DRAGON recoil separator at the TRIUMF Laboratory. The reaction cross section has been determined at energies between 0.6 and 1.6 MeV Ecm, reaching into the Gamow window for core helium burning for the first time. Resonance strengths for resonances at 0.63, 0.721, 0.81 and 1.122 MeV Ecm have been extracted. The experimentally based reaction rate calculated represents a lower limit, but suggests that significant s-process nucleosynthesis occurs in low metallicity massive stars., Comment: 7 pages, 5 figures

Published
2019
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2. $^{12}$C+$^{16}$O sub-barrier radiative capture cross-section measurements

Author

Goasduff, A., Courtin, S., Haas, F., Lebhertz, D., Jenkins, D. G., Beck, C., Fallis, J., Ruiz, C., Hutcheon, D. A., Amandruz, P. -A., Davis, C., Hager, U., Ottewell, D., and Ruprecht, G.

Subjects
Nuclear Experiment
Abstract

We have performed a heavy ion radiative capture reaction between two light heavy ions, $^{12}$C and $^{16}$O, leading to $^{28}$Si. The present experiment has been performed below Coulomb barrier energies in order to reduce the phase space and to try to shed light on structural effects. Obtained $\gamma$-spectra display a previously unobserved strong feeding of intermediate states around 11 MeV at these energies. This new decay branch is not fully reproduced by statistical nor semi-statistical decay scenarii and may imply structural effects. Radiative capture cross-sections are extracted from the data., Comment: 4 pages, 7 figures, to appear as proceedings of FUSION 2011 conference at St-Malo, France

Published
2011
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3. Some remarks about the beta-delayed alpha-decay of 16N

Author

Buchmann, L., Ruprecht, G., and Ruiz, C.

Subjects
Nuclear Experiment
Abstract

The beta-delayed alpha-decay of 16N has been used to restrict the E1 fraction of the ground state gamma-transition in the astrophysically important 12C(alpha,gamma)16O reaction in several experiments including those performed at TRIUMF and several other laboratories. A review of the published measurements is given, and GEANT4 simulations and R-Matrix calculations are presented to further clarify the observed alpha spectra. A clear response-function, in the form of a low-energy tail from the scattering of alpha-particles in the catcher foil is observed in these simulations for any foil thickness. Contrary to claims in the literature, the simulations show that the TRIUMF measurement and those performed at Yale and Mainz originate from the same underlying spectrum. The simulations suggests that the discrepancies between the Yale and TRIUMF final results can be attributed to incorrect deconvolution methods applied in the former case. The simulations show in general that the form (width) of the spectrum is very sensitive to the catcher foil thickness. It is concluded that the TRIUMF measurement most likely represents the currently closest approximation to the true beta-delayed alpha-decay spectrum of 16N., Comment: 27 figures, accepted by Physical Reviev C

Published
2009

4. Beta-delayed deuteron emission from 11Li: decay of the halo

Author

Raabe, R., Andreyev, A., Borge, M. J. G., Buchmann, L., Capel, P., Fynbo, H. O. U., Huyse, M., Kanungo, R., Kirchner, T., Mattoon, C., Morton, A. C., Mukha, I., Pearson, J., Ponsaers, J., Ressler, J. J., Riisager, K., Ruiz, C., Ruprecht, G., Sarazin, F., Tengblad, O., Van Duppen, P., and Walden, P.

Subjects
Nuclear Experiment
Abstract

The deuteron-emission channel in the beta-decay of the halo-nucleus 11Li was measured at the ISAC facility at TRIUMF by implanting post-accelerated 11Li ions into a segmented silicon detector. The events of interest were identified by correlating the decays of 11Li with those of the daughter nuclei. This method allowed the energy spectrum of the emitted deuterons to be extracted, free from contributions from other channels, and a precise value for the branching ratio B_d = 1.30(13) x 10-4 to be deduced for E(c.m.) > 200 keV. The results provide the first unambiguous experimental evidence that the decay takes place essentially in the halo of 11Li, and that it proceeds mainly to the 9Li + d continuum, opening up a new means to study of the halo wave function of 11Li., Comment: 4 pages, 3 figures

Published
2008
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5. Enhancement of the Deuteron-Fusion Reactions in Metals and its Experimental Implications

Author

Huke, A., Czerski, K., Heide, P., Ruprecht, G., Targosz, N., and Żebrowski, W.

Subjects
Nuclear Experiment
Abstract

Recent measurements of the reaction d(d,p)t in metallic environments at very low energies performed by different experimental groups point to an enhanced electron screening effect. However, the resulting screening energies differ strongly for divers host metals and different experiments. Here, we present new experimental results and investigations of interfering processes in the irradiated targets. These measurements inside metals set special challenges and pitfalls which make them and the data analysis particularly error-prone. There are multi-parameter collateral effects which are crucial for the correct interpretation of the observed experimental yields. They mainly originate from target surface contaminations due to residual gases in the vacuum as well as from inhomogeneities and instabilities in the deuteron density distribution in the targets. In order to address these problems an improved differential analysis method beyond the standard procedures has been implemented. Profound scrutiny of the other experiments demonstrates that the observed unusual changes in the reaction yields are mainly due to deuteron density dynamics simulating the alleged screening energy values. The experimental results are compared with different theoretical models of the electron screening in metals. The Debye-H\"{u}ckel model that has been previously proposed to explain the influence of the electron screening on both nuclear reactions and radioactive decays could be clearly excluded., Comment: 22 pages, 12 figures, REVTeX4, 2-column format. Submitted to Phys. Rev. C; accepted

Published
2008
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6. Measurement of two-halo neutron transfer reaction p($^{11}$Li,$^{9}$Li)t at 3$A$ MeV

Author

Tanihata, I., Alcorta, M., Bandyopadhyay, D., Bieri, R., Buchmann, L., Davids, B., Galinski, N., Howell, D., Mills, W., Openshaw, R., Padilla-Rodal, E., Ruprecht, G., Sheffer, G., Shotter, A. C., Mythili, S., Trinczek, M., Walden, P., Savajols, H., Roger, T., Caamano, M., Mittig, W., Roussel-Chomaz, P., Kanungo, R., Gallant, A., Savard, G., and Thompson, I. J.

Subjects
Nuclear Experiment
Abstract

The p(\nuc{11}{Li},\nuc{9}{Li})t reaction has been studied for the first time at an incident energy of 3$A$ MeV delivered by the new ISAC-2 facility at TRIUMF. An active target detector MAYA, build at GANIL, was used for the measurement. The differential cross sectionshave been determined for transitions to the \nuc{9}{Li} ground andthe first excited states in a wide range of scattering angles. Multistep transfer calculations using different \nuc{11}{Li} model wave functions, shows that wave functions with strong correlations between the halo neutrons are the most successful in reproducing the observation., Comment: 6 pages, 3 figures, submitted to Physical Review Letters

Published
2008
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7. Lifetimes of states in 19Ne above the 15 O + alpha breakup threshold

Author

Mythili, S., Davids, B., Alexander, T. K., Ball, G. C., Chicoine, M., Chakrawarthy, R. S., Churchman, R., Forster, J. S., Gujrathi, S., Hackman, G., Howell, D., Kanungo, R., Leslie, J. R., Padilla, E., Pearson, C. J., Ruiz, C., Ruprecht, G., Schumaker, M. A., Tanihata, I., Vockenhuber, C., Walden, P., and Yen, S.

Subjects
Nuclear Experiment
Abstract

The 15O(alpha,gamma)19Ne reaction plays a role in the ignition of Type I x-ray bursts on accreting neutron stars. The lifetimes of states in 19Ne above the 15O + alpha threshold of 3.53 MeV are important inputs to calculations of the astrophysical reaction rate. These levels in 19Ne were populated in the 3He(20Ne,alpha)19Ne reaction at a 20Ne beam energy of 34 MeV. The lifetimes of six states above the threshold were measured with the Doppler shift attenuation method (DSAM). The present measurements agree with previous determinations of the lifetimes of these states and in some cases are considerably more precise.

Published
2007
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12. Energy intensitites, EROI (energy returned on invested), for electric energy sources

Author

Weissbach D., Herrmann F., Ruprecht G., Huke A., Czerski K., Gottlieb S., and Hussein A.

Subjects
Physics, QC1-999
Abstract

The EROI (Energy Returned On Invested) has been calculated for various systems, especially power plants, applying several different methodologies. This quantity is often used as an argument in discussions about economics to emphasize the performance of a certain technology. Contrary to that, the publications often answer different questions, e.g. analyses of emissions or material flows, rendering the EROI unphysical. The present work introduces a physical approach based on exergy flows for EROI calculation to pinpoint and compare the efficiency of different power plant technologies.

Published
2018
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15. Nuclear Astrophysics at TRIUMF

Author

Buchmann, L., Amaudruz, P., D'Auria, J., Hutcheon, D., Matei, C., Pearson, J., Ruiz, C., Ruprecht, G., Trinczek, M., Vockenhuber, C., and Walden, P.

Published
2008
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16. Recent results of experiments with radioactive 21Na and 7Be ion beams

Author

Greife, U., Livesay, J., Jewett, C., Chipps, K., Sarazin, F., Bardayan, D., Blackmon, J., Nesaraja, C., Smith, M.S., Champagne, A., Fitzgerald, R., Jones, K., Thomas, J., Kozub, R., Buchmann, L., Caggiano, J., Hunter, D., Hutcheon, D., Olin, A., Ottewell, D., Rogers, J., Ruiz, C., Ruprecht, G., Trinczek, M., Vockenhuber, C., Bishop, S., D’Auria, J., Lamay, M., Liu, W., Wrede, C., Chatterjee, M.L., Chen, A.A., Pearson, J., Engel, S., Laird, A.M., Gigliotti, D., and Hussein, A.

Published
2007
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17. The 40Ca(α, γ)44Ti reaction at DRAGON

Author

Vockenhuber, C., Ouellet, C.O., Buchmann, L., Caggiano, J., Chen, A.A., D’Auria, J.M., Frekers, D., Hussein, A., Hutcheon, D.A., Kutschera, W., Jayamanna, K., Ottewell, D., Paul, M., Pearson, J., Ruiz, C., Ruprecht, G., Trinczek, M., and Wallner, A.

Published
2007
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18. A direct measurement of the 17O(α,γ)21Ne reaction in inverse kinematics and its impact on heavy element production

Author

Taggart, Matthew Paul, Akers, C., Laird, Alison Monica, Hager, U, Ruiz, C, Hutcheon, D, Bentley, Michael Anthony, Brown, James Robert, Buchmann, L, Chen, Jie, Chipps, Kelly Anne, Choplin, A., D'Auria, J.M., Davids, B, Davis, C, Diget, Christian Aaen, Erikson, L., Fallis, J., Fox, Simon Paul, Frischknecht, U., Fulton, Brian Robert, Galinski, N., Greife, U, Hirschi, R., Howell, D., Martin, L., Mountford, D. J., Murphy, A, Ottewell, D., Pignatari, M., Reeve, Scott, Ruprecht, G, Sjue, S. K. L., Veloce, L., and Williams, M.

Published
2019

23. Commissioning the DRAGON facility at ISAC

Author

Engel, S., Hutcheon, D., Bishop, S., Buchmann, L., Caggiano, J., Chatterjee, M.L., Chen, A.A., D’Auria, J., Gigliotti, D., Greife, U., Hunter, D., Hussein, A., Jewett, C.C., Laird, A.M., Lamey, M., Liu, W., Olin, A., Ottewell, D., Pearson, J., Ruiz, C., Ruprecht, G., Trinczek, M., Vockenhuber, C., and Wrede, C.

Published
2005
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24. A direct measurement of the O( , ) Ne reaction in inverse kinematics and its impact on heavy element production

Author

Taggart, M.P., Akers, C., Laird, A.M., Hager, U., Ruiz, C., Hutcheon, D.A., Bentley, M.A., Brown, J.R., Buchmann, L., Chen, A.A., Chen, J., Chipps, K.A., Choplin, A., D'Auria, J.M., Davids, B., Davis, C., Diget, C.Aa., Erikson, L., Fallis, J., Fox, S.P., Frischknecht, U., Fulton, B.R., Galinski, N., Greife, U., Hirschi, R., Howell, D., Martin, L., Mountford, D., Murphy, A.St.J., Ottewell, D., Pignatari, M., Reeve, S., Ruprecht, G., Sjue, S., Veloce, L., and Williams, M.

Subjects
Nuclear Experiment, Computer Science::Digital Libraries
Abstract

During the slow neutron capture process in massive stars, reactions on light elements can both produce and absorb neutrons thereby influencing the final heavy element abundances. At low metallicities, the high neutron capture rate of $^{16}$O can inhibit s-process nucleosynthesis unless the neutrons are recycled via the $^{17}$O(α,n)$^{20}$Ne reaction. The efficiency of this neutron recycling is determined by competition between the $^{17}$O(α,n)$^{20}$Ne and $^{17}$O(α,γ)$^{21}$Ne reactions. While some experimental data are available on the former reaction, no data exist for the radiative capture channel at the relevant astrophysical energies.The $^{17}$O(α,γ)$^{21}$Ne reaction has been studied directly using the DRAGON recoil separator at the TRIUMF Laboratory. The reaction cross section has been determined at energies between 0.6 and 1.6 MeV Ecm, reaching into the Gamow window for core helium burning for the first time. Resonance strengths for resonances at 0.63, 0.721, 0.81 and 1.122 MeV Ecm have been extracted. The experimentally based reaction rate calculated represents a lower limit, but suggests that significant s-process nucleosynthesis occurs in low metallicity massive stars.

Published
2019

25. A direct measurement of the ¹⁷O(α,γ)²¹Ne reaction in inverse kinematics and its impact on heavy element production

Author

Taggart, M.P., Akers, C., Laird, A.M., Hager, U., Ruiz, C., Hutcheon, D.A., Bentley, M.A., Brown, J.R., Buchmann, L., Chen, A.A., Chen, J., Chipps, K.A., Choplin, A., D'Auria, J.M., Davids, B., Davis, C., Diget, C.Aa., Erikson, L., Fallis, J., Fox, S.P., Frischknecht, U., Fulton, B.R., Galinski, N., Greife, U., Hirschi, R., Howell, D., Martin, L., Mountford, D., Murphy, A.St.J., Ottewell, D., Pignatari, M., Reeve, S., Ruprecht, G., Sjue, S., Veloce, L., and Williams, M.

Abstract

During the slow neutron capture process in massive stars, reactions on light elements can both produce and absorb neutrons thereby influencing the final heavy element abundances. At low metallicities, the high neutron capture rate of 16O can inhibit s-process nucleosynthesis unless the neutrons are recycled via the ¹⁷O(α,n)²⁰Ne reaction. The efficiency of this neutron recycling is determined by competition between the ¹⁷O(α,n)²⁰Ne and ¹⁷O(α,γ)²¹Ne reactions. While some experimental data are available on the former reaction, no data exist for the radiative capture channel at the relevant astrophysical energies. The ¹⁷O(α,n)²⁰Ne reaction has been studied directly using the DRAGON recoil separator at the TRIUMF Laboratory. The reaction cross section has been determined at energies between 0.6 and 1.6 MeV , reaching into the Gamow window for core helium burning for the first time. Resonance strengths for resonances at 0.63, 0.721, 0.81 and 1.122 MeV have been extracted. The experimentally based reaction rate calculated represents a lower limit, but suggests that significant s-process nucleosynthesis occurs in low metallicity massive stars.

Published
2019

26. TACTIC : The TRIUMF Annular Chamber for Tracking and Identification of Charged particles

Author

Martin, C. L., Ruprecht, G, Hager, U, Amaudruz, P. A., Buchmann, L, Fox, S. P., Laird, A. M., and Martin, E.

Abstract

An in-depth characterization of the TACTIC detector was performed using data from a 148Gd alpha source and some test runs with a stable ion beam. The detector is an active target time-projection chamber with a blind central region for maximizing beam tolerance and GEM-based electron amplification, equipped with a modern digitizing data acquisition system allowing the recording of full signals. The system was developed to study the reaction 8Li(α,n)11B, which is important for bridging the mass 8 gap in scenarios of low 4He density like Inhomogeneous Big Bang Nucleosynthesis and the production of r-process seeds in supernovae. Both energy resolution and tracking accuracy were found to agree with theoretical predictions and Geant4 simulations. The 8Li beam rate capability of the system is predicted to be of the order of 105s-1, several orders of magnitude higher than most previous measurements of the same reaction, while still maintaining a high detection efficiency of 70% to 80 %.

Published
2018

27. 12C+16O sub-barrier radiative capture cross-section measurements

Author

Hutcheon D.A., Ruiz C., Beck C., Fallis J., Jenkins D.G., Lebhertz D., Haas F., Courtin S., Goasduff A., Amandruz P.-A., Davis C., Hager U., Ottewell D., and Ruprecht G.

Subjects
Physics, QC1-999
Abstract

We have performed a heavy ion radiative capture reaction between two light heavy ions, 12C and 16O, leading to 28Si. The present experiment has been performed below Coulomb barrier energies in order to reduce the phase space and to try to shed light on structural effects. Obtained γ-spectra display a previously unobserved strong feeding of intermediate states around 11 MeV at these energies. This new decay branch is not fully reproduced by statistical nor semi-statistical decay scenarii and may imply structural effects. Radiative capture cross-sections are extracted from the data.

Published
2011
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30. Annual survey of fidelity and surety law, 1990.

Author

May, Ronald A., Ruprecht, G. Steven, Leslie, Robert E., Devin, Paul R., and Linder, Charles W., Jr.

Subjects
Letting of contracts -- Surveys, Surety bonds -- Surveys, Public contracts -- Surveys
Published
1991

31. Annual survey of fidelity and surety law, 1989.

Author

May, Ronald A., Ruprecht, G. Steven, Turner, Frederick D., Hollobaugh, Lewis B., and Linder, Charles W., Jr.

Subjects
Surety bonds -- Surveys, Contractors -- Cases
Published
1990

34. Structure of states in 12Be via the 11Be(d,p) reaction

Author

Kanungo, R., Gallant, A.T., Uchida, M., Andreoiu, C., Austin, R.A.E., Bandyopadhyay, D., Ball, G.C., Becker, J.A., Boston, A.J., Boston, H.C., Brown, B.A., Buchmann, L., Colosimo, S.J., Clark, R.M., Cline, D., Cross, D.S., Dare, H., Davids, B., Drake, T.E., Djongolov, M., Finlay, P., Galinski, N., Garrett, P.E., Garnsworthy, A.B., Green, K.L., Grist, S., Hackman, G., Harkness, L.J., Hayes, A.B., Howell, D., Hurst, A.M., Jeppesen, H.B., Leach, K.G., Macchiavelli, A.O., Oxley, D., Pearson, C.J., Pietras, B., Phillips, A.A., Rigby, S.V., Ruiz, C., Ruprecht, G., Sarazin, F., Schumaker, M.A., Shotter, A.C., Sumitharachchi, C.S., Svensson, C.E., Tanihata, I., Triambak, S., Unsworth, C., Williams, S.J., Walden, P., Wong, J., and Wu, C.Y.

Subjects
Nuclear and High Energy Physics
Published
2010
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36. Energy intensitites, EROI (energy returned on invested), for electric energy sources.

Author

Cifarelli, L., Wagner, F., Weissbach, D., Herrmann, F., Ruprecht, G., Huke, A., Czerski, K., Gottlieb, S., and Hussein, A.

Subjects
RENEWABLE energy sources, EXERGY, POWER plants, AUTOMATION, ELECTRICITY
Abstract

The EROI (Energy Returned On Invested) has been calculated for various systems, especially power plants, applying several different methodologies. This quantity is often used as an argument in discussions about economics to emphasize the performance of a certain technology. Contrary to that, the publications often answer different questions, e.g. analyses of emissions or material flows, rendering the EROI unphysical. The present work introduces a physical approach based on exergy flows for EROI calculation to pinpoint and compare the efficiency of different power plant technologies. [ABSTRACT FROM AUTHOR]

Published
2018
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38. The 12C(16O,γ 28Si) radiative capture reaction at sub-barrier energies

Author

Goasduff, A., Courtin, S., Haas, F., Lebhertz, D., Jenkins, D.G., Fallis, J., Ruiz, C., Hutcheon, D.A., Amandruz, P.-A., Davis, C., Hager, U., Ottewell, D., Ruprecht, G., CSNSM SNO, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
25.70.Gh, 25.70.Ef, 23.20.−g, 27.30.+t, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Published
2014

41. Beam suppression of the DRAGON recoil separator for He-3(alpha,gamma)Be-7

Author

Sjue, S.K.L., Nara Singh, B.S., Adsley, P., Buchmann, L., Carmona Gallardo, M., Davids, B., Fallis, J., Fulton, B.R., Galinski, N., Hager, U., Hass, M., Howell, D., Hutcheon, D.A., Laird, A.M., Martín, L., Ottewell, D., Reeve, S., Ruiz, C., Ruprecht, G., and Triambak, S.

Subjects
Recoil separator, Radiative capture reaction, Beam suppression
Abstract

Preliminary studies in preparation for an absolute cross-section measurement of the radiative capture reaction 3He(α,γ)7Be with the DRAGON recoil separator have demonstrated beam suppression >1014 at the 90% confidence level. A measurement of this cross section by observation of 7Be recoils at the focal plane of the separator should be virtually background free. & 2012 Elsevier B.V.

Published
2013

42. 12C+16O: Properties of sub-barrier resonance γ-decay

Author

Goasduff, A., Courtin, S., Haas, F., Lebhertz, D., Jenkins, D.G., Fallis, J., Ruiz, C., Hutcheon, D.A., Amandruz, P.-A., Davis, C., Hager, U., Ottewell, D., Ruprecht, G., Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), T. Niksic, M. Milin, D. Vretenar, and S. Szilzer

Subjects
resonances, radiative capture, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], cluster, 21.10.Re, 21.60.Gx
Abstract

International audience; In a recent experiment performed at Triumf using the Dragon 0◦ spectrometer and its associated BGO array, the complete γ -decay of the radiative capture channel below the Coulomb barrier has been measured for the first time. This measurement has been performed at two energies Ec.m. = 6.6 and 7.2 MeV. A selective contribution of the entrance

Published
2012

43. The first direct measurement of 17O(α,γ)21Ne and its impact upon s-process abundances

Author

Taggart, M., Hager, U., Laird, A. M., Ruiz, C., Hutcheon, D., Ottewell, D., Fallis, J., Erikson, L., Bentley, M., Brown, J. R., Buchmann, L., Chen, A. A., Jun Chen, Chipps, K. A., D Auria, J., Davids, B., Davis, C., Diget, C. A., Fox, S. P., Fulton, B., Galinski, N., Greife, U., Herwig, F., Hirschi, R., Howell, D., Martin, L., Mountford, D., Murphy, A., Pignatari, M., Reeve, S., Ruprecht, G., Sjue, S., and Veloce, L.

Abstract

An experimental campaign to perform the first accurate measurement of the 17O(a,g)21Ne reaction rate was carried out during May and November 2009 at the DRAGON recoil separator in the TRIUMF laboratory, Vancouver, Canada. The goals were to differentiate between two previous conflicting theoretical predictions, and to establish the (a,g)/(a,n) reaction rate ratio.Two distinct energy regions were scanned: a higher region, Ecm 1.5 MeV, where the recoil cone was sufficiently confined and the cross section sufficiently large so that a statistically significant yield could be achieved, and a lower region, Ecm 0.7 MeV, chosen to approach the astrophysicalenergies and reduce errors from extrapolation. The experiment, performed in inverse kinematics, used the highest intensity beam ever deliveredto DRAGON, 11012 pps of 17O incident on a 4He gas target. An array of 30 Bismuth Germanate (BGO) detectors [1] was used in conjunction with two microchannel plates (MCP) [2] for a local time-of-flight measurement, and ion chamber for coincident event detection.

Published
2010

44. Lifetime measurements of states inO15

Author

Galinski, N., primary, Sjue, S. K. L., additional, Ball, G. C., additional, Cross, D. S., additional, Davids, B., additional, Al Falou, H., additional, Garnsworthy, A. B., additional, Hackman, G., additional, Hager, U., additional, Howell, D. A., additional, Jones, M., additional, Kanungo, R., additional, Kshetri, R., additional, Leach, K. G., additional, Leslie, J. R., additional, Moukaddam, M., additional, Orce, J. N., additional, Rand, E. T., additional, Ruiz, C., additional, Ruprecht, G., additional, Schumaker, M. A., additional, Svensson, C. E., additional, Triambak, S., additional, and Unsworth, C. D., additional

Published
2014
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45. Study of two neutron transfer reaction and resonnant elastic scattering induced by 11Li, with the MAYA active target

Author

Roger, T., Savajols, H., Tanihata, I., Mittig, W., Alcorta, M., Bandyopadhyay, D., Bieri, R., Buchmann, L., Caamano, M., Davids, B., Galinski, N., Gallant, A., Howell, D., Kanungo, R., Mills, W., Notani, M., Openshaw, R., Padilla-Rodal, E., Roussel-Chomaz, P., Ruprecht, G., Savard, G., Sheffer, G., Shotter, A.C., Mythili, S., Trinczek, M., Walde, P., Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Lion, Michel

Subjects
[PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

Active targets are perfect tools for the study of reactions induced by radioactive ion beams of very low intensity. Thus, they make possible the study of direct and compound reactions at the same time. In this talk, we will present the results obtained with the MAYA active target for low energy reactions induced by the halo nucleus 11Li. A method used to measure the mass of short-lived nuclei, applied to the 11Li case will be discussed. The experimantal angular distribution of the two halo-neutron transfer reaction 1H(11Li,9Li)t at 4.3A MeV, using the MAYA detector as a thin target, will be presented and compared to coupled reaction channel calculations including 3-body models in order to extract informations on the structure of the 11Li halo. The extraction of the 11Li+p optical potential using the data on the elastic scattering, will also be discussed. Finally, the excitation function of the resonant elastic scattering reaction, determined using the MAYA detector as a thick target, will be presented. Extraction of information on the structure of possible 12Li isobaric analog states observed in 12Be using several R-matrix calculations will be shown.

Published
2009

46. Mass of $^{11}$Li from the $^{1}$H($^{11}$Li, $^{9}$Li)$^{3}$H reaction

Author

Roger, T., Savajols, H., Tanihata, I., Mittig, W., Alcorta, M., Bandyopadhyay, D., Bieri, R., Buchmann, L., Caamano, M., Davids, B., Galinski, N., Gallant, A., Howell, D., Kanungo, R., Mills, W., Mythili, S., Notani, M., Openshaw, R., Padilla-Rodal, E., Roussel-Chomaz, P., Ruprecht, G., Savard, G., Sheffer, G., C. Shotter, A., Trinczek, M., Walden, P., Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), TRIUMF [Vancouver], Saint Mary's University [Halifax], ANL, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 21.10.Dr, 25.60.Je, 27.20.+n, 29.40.Gx
Abstract

Active target MAYA, expérience TRIUMF; The mass of 11Li has been determined from Q-value measurements of the 1H(11Li, 9Li)3H reaction. The experiment was performed at TRIUMF laboratory with the GANIL active target MAYA. Energy-energy and angle-angle kinematics reconstruction give a Q value of 8.119(22) MeV for the reaction. The derived 11Li two-neutron separation energy is S2n = 363(22) keV.

Published
2009

47. Precise measurement of the beta decay and electron capture of Na-22, Au-198, and Au-196 in low-temperature metal hosts, and reexamination of lifetime modifications

Author

Ruprecht, G., Vockenhuber, C., Buchmann, L., Woods, R., Ruiz, C., Lapi, S., and Bemmerer, D.

Subjects
Half-life Au-198 Au-196 Na-22 Debye-Hückel model Salpeter screening weakly coupled plasma
Abstract

We investigated half-life changes with temperature of 22Na embedded in Al and 198Au/196Au embedded in Au. We do not find any change of the half-life between room temperature and 10 K on the level of 0.04% for 22Na, 0.03% for 198Au, and 0.5% for 196Au in striking disagreement with the first experimental works and predictions. Additionally, the absolute half-life for 198Au has been determined to 2.6937±0.0003 d which is 5 standard deviations below the recommended NIST value but in agreement with other high-precision measurements.

Published
2008

48. β-Delayed Deuteron Emission from 11Li: Decay of the Halo

Author

Raabe, R., Andreyev, A., Borge, M. J. G., Buchmann, L., Capel, P., Fynbo, Hans Otto Uldall, Huyse, M., Kanungo, R., Kirchner, T., Mattoon, C., Morton, A. C., Mukha, I., Pearson, J., Ponsaers, J., Ressler, J. J., Riisager, Karsten, Ruiz, C., Ruprecht, G., Sarazin, F., Tengblad, O., Van Duppen, P., and Walden, P.

Published
2008

49. Decay strength distributions in $^{12}C(^{12}C,\gamma)$ radiative capture

Author

Jenkins, D.G., Fulton, B.R., Marley, P., Fox, S.P., Glover, R., Wadsworth, R., Watson, D.L., Courtin, S., Haas, F., Lebhertz, D., Beck, C., Papka, P., Rousseau, Marc, Sànchez I Zafra, A., Hutcheon, D.A., Davis, C., Ottewell, D., Pavan, M.M., Pearson, Justin, Ruiz, C., Ruprecht, G., Slater, J., Trinczek, M., D'Auria, J., Lister, C.J., Chowdhury, P., Andreoiu, C., Valiente-Dobón, J.J., Moon, S., Département Recherches Subatomiques (DRS-IPHC), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
21.60.Gx, 25.40.Lw, 27.30.+t, 29.30.Kv, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

The heavy-ion radiative capture reaction, 12C(12C,$\gamma$), has been investigated at energies both on- and off-resonance, with a particular focus on known resonances at Ec.m.=6.0, 6.8, 7.5, and 8.0 MeV. Gamma rays detected in a BGO scintillator array were recorded in coincidence with 24Mg residues at the focal plane of the DRAGON recoil separator at TRIUMF. In this manner, the relative strength of all decay pathways through excited states up to the particle threshold could be examined for the first time. Isovector M1 transitions are found to be a important component of the radiative capture from the Ec.m.=6.0 and 6.8 MeV resonances. Comparison with Monte Carlo simulations suggests that these resonances may have either J=0 or 2, with a preference for J=2. The higher energy resonances at Ec.m.=7.5 and 8.0 MeV have a rather different decay pattern. The former is a clear candidate for a J=4 resonance, whereas the latter has a dominant J=4 character superposed on a J=2 resonant component underneath. The relationship between these resonances and the well-known quasimolecular resonances as well as resonances in breakup and electrofission of 24Mg into two 12C nuclei are discussed.

Published
2007

50. Study of the $^{40}Ca(\alpha, \gamma)^{44}Ti$ reaction at stellar temperatures with DRAGON

Author

Vockenhuber, C, Ouellet, C O, Buchmann, L, Caggiano, J A, Chen, A A, Crawford, H, D'Auria, J, Davids, B, Fogarty, L, Frekers, D, Hussein, A, Hutcheon, D A, Kutschera, W, Laird, A M, Lewis, R, O'Connor, E, Ottewell, D F, Paul, M, Pavan, M, Pearson, J, Ruiz, C, Ruprecht, G, Trinczek, M, Wales, B, and Wallner, A

Subjects
Astrophysics and Astronomy
Published
2006

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