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Fang X, Tan WP, Beard M, deBoer RJ, Gilardy G, Jung H, Liu Q, Lyons S, Robertson D, Setoodehnia K, Seymour C, Stech E, Vande Kolk B, Wiescher M, de Souza R, Hudan S, Singh V, Tang XD, Uberseder E. Experimental measurement of the 12C+ 16O fusion cross sections at astrophysical energies. EPJ Web Conf 2018. [DOI: 10.1051/epjconf/201817804008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The total cross sections of the 12C+16O fusion have been experimentally determined at low energies to investigate the role of this reaction during late stellar evolution burning phases. A high-intensity oxygen beam was produced by the 5MV pelletron accelerator at the University of Notre Dame impinging on a thick ultra-pure graphite target. Protons and γ-rays were measured simultaneously in the center-of-mass energy range from 3.64 to 5.01 MeV, using strip silicon and HPGe detectors. Statistical model calculations were employed to interpret the experimental results. A new broad resonance-like structure is observed for the 12C+16O reaction, and a decreasing trend of its S-factor towards low energies is found.
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Barbui M, Hagel K, Gauthier J, Wuenschel S, de Souza RT, Hudan S, Fang D, Goldberg V, Zheng H, Giuliani G, Rapisarda G, Kim EJ, Liu X, Natowitz J. Study of 12C excited states decaying into three αparticles using the thick target inverse kinematic technique. EPJ Web of Conferences 2016. [DOI: 10.1051/epjconf/201611707013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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3
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Wiggins BB, Richardson E, Siwal D, Hudan S, deSouza RT. Optimizing the position resolution of a Z-stack microchannel plate resistive anode detector for low intensity signals. Rev Sci Instrum 2015; 86:083303. [PMID: 26329177 DOI: 10.1063/1.4927457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/14/2015] [Indexed: 06/05/2023]
Abstract
A method for achieving good position resolution of low-intensity electron signals using a microchannel plate resistive anode detector is demonstrated. Electron events at a rate of 7 counts s(-1) are detected using a Z-stack microchannel plate. The dependence of position resolution on both the distance and the potential difference between the microchannel plate and resistive anode is investigated. Using standard commercial electronics, a measured position resolution of 170 μm (FWHM) is obtained, which corresponds to an intrinsic resolution of 157 μm (FWHM).
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Affiliation(s)
- B B Wiggins
- Department of Chemistry and Center for Exploration of Energy and Matter, Indiana University, 2401 N. Milo B. Sampson Ln., Bloomington, Indiana 47408, USA
| | - E Richardson
- Department of Chemistry and Center for Exploration of Energy and Matter, Indiana University, 2401 N. Milo B. Sampson Ln., Bloomington, Indiana 47408, USA
| | - D Siwal
- Department of Chemistry and Center for Exploration of Energy and Matter, Indiana University, 2401 N. Milo B. Sampson Ln., Bloomington, Indiana 47408, USA
| | - S Hudan
- Department of Chemistry and Center for Exploration of Energy and Matter, Indiana University, 2401 N. Milo B. Sampson Ln., Bloomington, Indiana 47408, USA
| | - R T deSouza
- Department of Chemistry and Center for Exploration of Energy and Matter, Indiana University, 2401 N. Milo B. Sampson Ln., Bloomington, Indiana 47408, USA
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4
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deSouza RT, Gosser ZQ, Hudan S. Using induced signals to sense position from a microchannel plate detector. Rev Sci Instrum 2012; 83:053305. [PMID: 22667615 DOI: 10.1063/1.4723821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We demonstrate a novel concept for a position sensitive microchannel plate detector. This detector provides sub-millimeter spatial resolution by examining the signal induced on a wire harp by the electron cloud from a microchannel plate detector. Wires in the harp are efficiently read out by coupling them to a delay line.
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Affiliation(s)
- R T deSouza
- Department of Chemistry and Center for Exploration of Energy and Matter, 2401 Milo B. Sampson Ln., Bloomington, Indiana 47405, USA.
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Rogers AM, Famiano MA, Lynch WG, Wallace MS, Amorini F, Bazin D, Charity RJ, Delaunay F, de Souza RT, Elson J, Gade A, Galaviz D, van Goethem MJ, Hudan S, Lee J, Lobastov S, Lukyanov S, Matoš M, Mocko M, Schatz H, Shapira D, Sobotka LG, Tsang MB, Verde G. Ground-state proton decay of 69Br and implications for the 68Se astrophysical rapid proton-capture process waiting point. Phys Rev Lett 2011; 106:252503. [PMID: 21770637 DOI: 10.1103/physrevlett.106.252503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Indexed: 05/31/2023]
Abstract
We report on the first direct measurement of the proton separation energy for the proton-unbound nucleus (69)Br. Bypassing the (68)Se waiting point in the rp process is directly related to the 2p-capture rate through (69)Br, which depends exponentially on the proton separation energy. We find a proton separation energy for (69)Br of Sp((69)Br )= -785(-40)(+34) keV; this is less bound compared to previous predictions which have relied on uncertain theoretical calculations. The influence of the extracted proton separation energy on the rp process occurring in type I x-ray bursts is examined within the context of a one-zone burst model.
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Affiliation(s)
- A M Rogers
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.
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Lee J, Tsang MB, Bazin D, Coupland D, Henzl V, Henzlova D, Kilburn M, Lynch WG, Rogers AM, Sanetullaev A, Signoracci A, Sun ZY, Youngs M, Chae KY, Charity RJ, Cheung HK, Famiano M, Hudan S, O'Malley P, Peters WA, Schmitt K, Shapira D, Sobotka LG. Neutron-proton asymmetry dependence of spectroscopic factors in ar isotopes. Phys Rev Lett 2010; 104:112701. [PMID: 20366470 DOI: 10.1103/physrevlett.104.112701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Indexed: 05/29/2023]
Abstract
Spectroscopic factors have been extracted for proton-rich 34Ar and neutron-rich 46Ar using the (p, d) neutron transfer reaction. The experimental results show little reduction of the ground state neutron spectroscopic factor of the proton-rich nucleus 34Ar compared to that of 46Ar. The results suggest that correlations, which generally reduce such spectroscopic factors, do not depend strongly on the neutron-proton asymmetry of the nucleus in this isotopic region as was reported in knockout reactions. The present results are consistent with results from systematic studies of transfer reactions but inconsistent with the trends observed in knockout reaction measurements.
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Affiliation(s)
- Jenny Lee
- NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
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7
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Bazin D, Charity RJ, de Souza RT, Famiano MA, Gade A, Henzl V, Henzlova D, Hudan S, Lee J, Lukyanov S, Lynch WG, McDaniel S, Mocko M, Obertelli A, Rogers AM, Sobotka LG, Terry JR, Tostevin JA, Tsang MB, Wallace MS. Mechanisms in knockout reactions. Phys Rev Lett 2009; 102:232501. [PMID: 19658928 DOI: 10.1103/physrevlett.102.232501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 04/08/2009] [Indexed: 05/28/2023]
Abstract
We report the first detailed study of the relative importance of the stripping and diffraction mechanisms involved in nucleon knockout reactions, by the use of a coincidence measurement of the residue and fast proton following one-proton knockout reactions. The measurements used the S800 spectrograph in combination with the HiRA detector array at the NSCL. Results for the reactions 9Be(9C,8B+X)Y and 9Be(8B,7Be+X)Y are presented and compared with theoretical predictions for the two reaction mechanisms calculated using the eikonal model. The data show a clear distinction between the stripping and diffraction mechanisms and the measured relative proportions are very well reproduced by the reaction theory. This agreement adds support to the results of knockout reaction analyses and their applications to the spectroscopy of rare isotopes.
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Affiliation(s)
- D Bazin
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824, USA.
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8
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McIntosh AB, Hudan S, Metelko CJ, de Souza RT, Charity RJ, Sobotka LG, Lynch WG, Tsang MB. Tidal effects and the proximity decay of nuclei. Phys Rev Lett 2007; 99:132701. [PMID: 17930582 DOI: 10.1103/physrevlett.99.132701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 03/30/2007] [Indexed: 05/25/2023]
Abstract
We examine the decay of the 3.03 MeV state of (8)Be evaporated from an excited projectilelike fragment following a peripheral heavy-ion collision. The relative energy of the daughter alpha particles exhibits a dependence on the decay angle of the (8)Be(*), indicative of a tidal effect. A comparison of the measured tidal effect with a model suggests a measurable nuclear proximity interaction.
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Affiliation(s)
- A B McIntosh
- Department of Chemistry and Indiana University Cyclotron Facility, Indiana University, Bloomington, Indiana 47405, USA
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Le Fèvre A, Auger G, Begemann-Blaich ML, Bellaize N, Bittiger R, Bocage F, Borderie B, Bougault R, Bouriquet B, Charvet JL, Chbihi A, Dayras R, Durand D, Frankland JD, Galichet E, Gourio D, Guinet D, Hudan S, Immé G, Lautesse P, Lavaud F, Legrain R, Lopez O, Łukasik J, Lynen U, Müller WFJ, Nalpas L, Orth H, Plagnol E, Raciti G, Rosato E, Saija A, Schwarz C, Seidel W, Sfienti C, Tamain B, Trautmann W, Trzciński A, Turzó K, Vient E, Vigilante M, Volant C, Zwiegliński B, Botvina AS. Isotopic scaling and the symmetry energy in spectator fragmentation. Phys Rev Lett 2005; 94:162701. [PMID: 15904219 DOI: 10.1103/physrevlett.94.162701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Indexed: 05/02/2023]
Abstract
Isotopic effects in the fragmentation of excited target residues following collisions of 12C on (112,124)Sn at incident energies of 300 and 600 MeV per nucleon were studied with the INDRA 4pi detector. The measured yield ratios for light particles and fragments with atomic number Z < or = 5 obey the exponential law of isotopic scaling. The deduced scaling parameters decrease strongly with increasing centrality to values smaller than 50% of those obtained for the peripheral event groups. Symmetry-term coefficients, deduced from these data within the statistical description of isotopic scaling, are near gamma = 25 MeV for peripheral and gamma < 15 MeV for central collisions.
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Affiliation(s)
- A Le Fèvre
- Gesellschaft für Schwerionenforschung mbH, D-64291 Darmstadt, Germany
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Borderie B, Tăbăcaru G, Chomaz P, Colonna M, Guarnera A, Pârlog M, Rivet MF, Auger G, Bacri CO, Bellaize N, Bougault R, Bouriquet B, Brou R, Buchet P, Chbihi A, Colin J, Demeyer A, Galichet E, Gerlic E, Guinet D, Hudan S, Lautesse P, Lavaud F, Laville JL, Lecolley JF, Leduc C, Legrain R, Le Neindre N, Lopez O, Louvel M, Maskay AM, Normand J, Pawlowski P, Rosato E, Saint-Laurent F, Steckmeyer JC, Tamain B, Tassan-Got L, Vient E, Wieleczko JP. Evidence for spinodal decomposition in nuclear multifragmentation. Phys Rev Lett 2001; 86:3252-3255. [PMID: 11327943 DOI: 10.1103/physrevlett.86.3252] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2000] [Indexed: 05/23/2023]
Abstract
Multifragmentation of a "fused system" was observed for central collisions between 32 MeV/nucleon 129Xe and (nat)Sn. Most of the resulting charged products were well identified due to the high performances of the INDRA 4pi array. Experimental higher-order charge correlations for fragments show a weak but nonambiguous enhancement of events with nearly equal-sized fragments. Supported by dynamical calculations in which spinodal decomposition is simulated, this observed enhancement is interpreted as a "fossil" signal of spinodal instabilities in finite nuclear systems.
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Affiliation(s)
- B Borderie
- Institut de Physique Nucléaire, IN2P3-CNRS, F-91406 Orsay Cedex, France
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