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Kruse, J.J.; Galonsky, A.; Snow, C.; Tryggestad, E.; Wang, J.; Ieki, K.; Iwata, Y.; Zecher, P.D., E-mail: kruse.jon@mayo.edu2002
AbstractAbstract
[en] We have developed a fragment detection system for use in studies of exotic, neutron-rich nuclei. Using a C-shaped dipole magnet, the system sweeps charged fragments and un-reacted beam particles through an angle before stopping them in an array of plastic scintillator detectors, recording time-of-flight and total energy. The system also includes a pair of silicon strip detectors to measure fragment angle of emergence from the target and energy loss for particle identification
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S0168900201013341; Copyright (c) 2002 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
Journal
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 480(2-3); p. 598-609
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Horvath, A.; Ieki, K.; Iwata, Y.; Kruse, J.J.; Seres, Z.; Wang, J.; Weiner, J.; Zecher, P.D.; Galonsky, A., E-mail: akos@ludens.elte.hu2000
AbstractAbstract
[en] The pulse-shape discrimination capability and the scintillation efficiency of two liquid scintillators, BC519 and NE213 (BC501A) have been compared. Pulse-shape discrimination is not as good with BC519, but for large light pulses it should be adequate in many applications and may be a useful alternative to NE213 because it has a higher ratio of H-to-C- atoms. Within 5% the scintillation efficiencies are the same when the scintillators are excited by protons with energies up to 11 MeV
Primary Subject
Source
S0168900299007974; Copyright (c) 2000 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Record Type
Journal Article
Journal
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 440(1); p. 241-244
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Ieki, K.; Sackett, D.; Galonsky, A.; Bertulani, C.A.; Kruse, J.J.; Lynch, W.G.; Morrissey, D.J.; Orr, N.A.; Schulz, H.; Sherrill, B.M.
Tours symposium on nuclear physics II1995
Tours symposium on nuclear physics II1995
AbstractAbstract
[en] A kinematically complete measurement of the Coulomb dissociation of the 28 MeV/nucleon 11Li into 9Li + 2n by a lead target was made. The photonuclear cross section σE1(E) and the dipole strength function dB(E1)/dE were determined. A short time scale of the breakup process indicated by the observed post-Coulomb acceleration effect prefers the direct breakup mechanism. From the narrow width of the momentum distributions in the 9Li and the neutrons, strong correlation between the two neutrons had been suggested. However, the momentum distributions were well reproduced with an assumption that the decay energy is parted according to the three-body phase space, i.e., no strong correlations were found between the neutrons. This fact also supports direct breakup mechanism. (authors). 40 refs., 5 figs
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Utsunomiya, H.; Ohta, M.; Galin, J.; Muenzenberg, G. (eds.); [594 p.]; ISBN 981-02-2156-8; ; 1995; p. 155-164; World Scientific; Singapore (Singapore); Tours symposium on nuclear physics II; Tours (France); 30 Aug - 2 Sep 1994
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Book
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Conference
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AbstractAbstract
[en] Two 2 m x 2 m ''walls'' were built for experiments with two neutrons in the final state. Each wall consists of 25 rectangular cells filled with NE-213 liquid scintillator. The close-packed design of the array makes cross-talk an inevitable contributor to distortion of measurements with this system. For En≤25 MeV almost all the detection efficiency comes from n-p scattering, and the simple two-body kinematics can be used as the basis for identifying cross-talk events. A Monte-Carlo code was developed to simulate the detection process. We found that most cross-talk events could be distinguished from real two-neutron events. A test experiment for comparison with the code was performed with neutrons from the 7Li(p,n)7Be reaction at Ep=30 MeV. With this reaction all two-detector coincidences are cross-talk events. Consistency between the experimental data and the simulation results was obtained. (orig.)
Source
9 refs.
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Journal Article
Journal
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 397(2-3); p. 380-390
Country of publication
BARYON REACTIONS, BARYON-BARYON INTERACTIONS, CALCULATION METHODS, COUNTING TECHNIQUES, DETECTION, ENERGY RANGE, HADRON REACTIONS, HADRON-HADRON INTERACTIONS, INTERACTIONS, MEASURING INSTRUMENTS, MEV RANGE, NUCLEAR REACTIONS, NUCLEON REACTIONS, NUCLEON-NUCLEON INTERACTIONS, PARTICLE INTERACTIONS, PROTON-NUCLEON INTERACTIONS, RADIATION DETECTION, RADIATION DETECTORS, SCINTILLATION COUNTERS, SIMULATION
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Galonsky, A.; Sackett, D.; Kruse, J.J.; Michigan State Univ., East Lansing, MI; Ieki, K.; Deak, F.; Horvath, A.; Seres, Z.; Kolata, J.J.; Warner, R.E.; Humphrey, D.L.
International workshop on multiparticle correlations and nuclear reactions. CORINNE II1995
International workshop on multiparticle correlations and nuclear reactions. CORINNE II1995
AbstractAbstract
[en] A kinematically complete measurement of the Coulomb dissociation of 11Li into 9Li + 2n by a Pb target was made for 11Li excitation energies up to ∼1.5 MeV. The 9Li velocity is greater than the average neutron velocity, indicating Coulomb acceleration of the 9Li by the Pb nucleus and, therefore, a prompt decay rather than a soft dipole resonance for the breakup process. The n-n momentum and angle correlations show no evidence for a dineutron in the ground state of 11Li. A brief discussion of two neutron walls under construction and of the problems of neutron spectroscopy with large detectors are given. (authors). 16 refs., 8 figs
Primary Subject
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Aichelin, J.; Ardouin, D. (Centre National de la Recherche Scientifique, 44 - Nantes (France). Lab. de Physique Subatomique et des Technologies Associees) (eds.); [492 p.]; ISBN 981-02-2118-5; ; 1995; p. 129-139; World Scientific; Singapore (Singapore); CORINNE II: International workshop on multiparticle correlations and nuclear reactions; Nantes (France); 6-10 Sep 1994
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Book
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Conference
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AbstractAbstract
[en] To further study neutron-rich halo nuclei, we have constructed a neutron detector array. The array consists of two separate banks of detectors, each of area 2 x 2 m2 and containing 250 l of liquid scintillator. Each bank is position-sensitive to better than 10 cm. For neutron time-of-flight measurements, the time resolution of the detector has been demonstrated to be about 1 ns. By using the scintillator NE-213, we are able to distinguish between neutron and γ-ray signals above 1 MeV electron equivalent energy. Although the detector array was constructed for a particular experiment it has also been used in a number of other experiments. (orig.)
Source
8 refs.
Record Type
Journal Article
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Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 401(2-3); p. 329-344
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AbstractAbstract
[en] Photodisintegration of 11Li was accomplished by sending a beam of 11Li at 28 MeV/nucleon through the equivalent photon field of a lead target. By measuring the complete kinematics of the disintegration products, 9Li+n+n, we constructed the correlation of the angle between the two neutrons in the rest frame of the 11Li. The correlation is independent of angle. This result argues against the existence of a bound dineutron in the ground state of 11Li. copyright 1996 The American Physical Society
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[en] Kinematically complete measurements for Coulomb dissociation of 11Li into 9Li+2n were made at 28 MeV/nucleon. The n-n correlation function suggests a large source size for the two-neutron emission. The electromagnetic excitation spectrum of 11Li has a peak, as anticipated in low-energy dipole resonance models, but a large post-breakup Coulomb acceleration of the 9Li fragment is observed, indicating a very short lifetime of the excited state and favoring direct breakup as the dissociation mechanism
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Journal Article
Literature Type
Numerical Data
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BETA DECAY RADIOISOTOPES, BETA-MINUS DECAY RADIOISOTOPES, CROSS SECTIONS, DATA, DETECTION, ELECTRIC FIELDS, ENERGY RANGE, FRAGMENTATION, INFORMATION, ISOTOPES, LIGHT NUCLEI, LITHIUM ISOTOPES, MANY-BODY PROBLEM, MEV RANGE, NUCLEAR REACTIONS, NUCLEI, NUMERICAL DATA, ODD-EVEN NUCLEI, PARTIAL WAVES, RADIATION DETECTION, RADIOISOTOPES, SPECTRA
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AbstractAbstract
[en] We have performed a kinematically complete measurement of the Coulomb dissociation of 28 MeV/nucleon 11Li into 9Li and two neutrons by a Pb target. From the energies and angles of the emitted neutrons and of 9Li, the excitation energy E of 11Li was determined on an event-by-event basis, and the Coulomb dissociation cross section as a function of excitation energy was constructed. The photonuclear cross section σE1(E) and the dipole strength function dB(E1)/dE were determined from the Coulomb dissociation cross section. σE1(E) has a peak at E=1.0 MeV and a width Γ=0.8 MeV. These parameters are consistent with the picture of a soft dipole mode. However, a significant post-breakup Coulomb acceleration of 9Li suggests instead a direct breakup. The complete kinematical measurement also allowed neutron and 9Li momentum distributions to be constructed in the rest frame of the 11Li. The momentum distributions were fitted with Gaussian functions, yielding width parameters σ9=18±4 MeV/c and σn=13±3 MeV/c. A more general feature of the breakup mechanism of 11Li could be deduced from these measurements. It was found that the 9Li and neutron momentum distributions and the neutron-neutron relative momentum distribution could be reproduced if the 11Li excitation energy was partitioned between the 9Li and the neutrons by a three-body phase space distribution. This indicates there is no directional correlation between the halo neutrons, and shows that the halo neutrons do not exist as a dineutron bound to a 9Li core
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AbstractAbstract
[en] We have made the first attempt at determining the 8Li(n,γ)9Li cross section at astrophysical energies. This reaction competes with the 8Li(α,n)11B reaction in the inhomogeneous big bang model and with 8Li β decay in the r process. It may affect the primordial abundance and the stellar production of A>12 nuclei. Using a radioactive beam of 9Li and the Coulomb dissociation method we attempted to measure the cross section of the inverse reaction 9Li(γ,n)8Li. We report only an upper limit because we were unable to determine and subtract the nuclear dissociation. Through the detailed balance theorem, this lead to an upper limit for the cross section of interest, 8Li(n,γ)9Li. The limit is 19±8 b for En = 0 endash 500 keV or, when expressed as a reaction rate, 7200cm3s-1mole-1. copyright 1998 The American Physical Society
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Journal Article
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BARYON REACTIONS, BARYONS, BETA DECAY RADIOISOTOPES, BETA-MINUS DECAY RADIOISOTOPES, BORON ISOTOPES, BOSONS, DECAY, ELEMENTARY PARTICLES, FERMIONS, HADRON REACTIONS, HADRONS, ISOTOPES, LIGHT NUCLEI, LITHIUM ISOTOPES, MASSLESS PARTICLES, NUCLEAR DECAY, NUCLEAR REACTIONS, NUCLEI, NUCLEON REACTIONS, NUCLEONS, ODD-EVEN NUCLEI, RADIOISOTOPES, STABLE ISOTOPES, STAR EVOLUTION, TARGETS
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