Reactions 7Li + n, 7Li + p and excited states of the A = 8 system

Presser, G.; Bass, R.

doi:10.1016/0375-9474(72)90281-3

Cited by 48 publications

(14 citation statements)

References 32 publications

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“…Li(p, n)7 Be reaction cross section. The ground state and first excitated state cross sections are shown along with the total cross section.E p < 25 MeV [AGZZ84]; 25 < E p < 26 MeV [PAD + 76].Spline fits that match selected experimental points were used to generate the evaluated cross section.To evaluate the cross section for production of the 0.4291 MeV 1/2 − excited state of 7 Be, we used the following data sets: 2.3 < E p < 5 MeV[PB72]; 5 < E p < 25 MeV [AGZZ84]; 25 < E p < 26 MeV…”

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confidence: 99%

2009 Release of the Evaluated Nuclear Data Library (ENDL2009)

Beck¹,

Brown²,

Descalle³

et al. 2010

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LLNL's Computational Nuclear Physics Group and Nuclear Theory and Modeling Group have collaborated to produce the next iteration of LLNL's evaluated nuclear database ENDL2009. ENDL2009 is the second in a series of major ENDL library releases designed to support LLNL's current and future nuclear data needs. This library contains many new evaluations for radiochemical diagnostics, structural materials, and thermonuclear reactions. We have striven to keep ENDL2009 at the leading edge of nuclear data library development by reviewing and incorporating new evaluations as they are made available to the nuclear data community. In addition, ENDL2009 support new features such as energy dependent Q values from fission and unresolved resonances. Furthermore, this is the first ENDL library release to be released in the TDF format. Finally, this release is our most highly tested release as we have strengthened our already rigorous testing regime by adding tests against LANL Activation Ratio Measurements and many more new critical assemblies. Our testing is now being incorporated into our development process and is serving to guide library improvements. Contents

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confidence: 99%

2009 Release of the Evaluated Nuclear Data Library (ENDL2009)

Beck¹,

Brown²,

Descalle³

et al. 2010

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“…A speculative explanation for the general increase in relative neutron emission for E x > 24 MeV in Figs. 2 and 3, might be isospin mixing, as described in Sokolov and Zelevinsky [25], of a broad simple state (for example, the wide (1 − , 2 − T = 1 giant resonance state at E x = 24 MeV [1,5]), and higher lying relatively narrow states .…”

Section: Discussionmentioning

confidence: 98%

“…Measurements of (d, n )/(d, p ) by Cecil, et al [3] and Czerski, et al [4], found significant deviations from unity, but covered a very limited energy range: 0.06-0.18 MeV. An extensive set of measurements, comparing the 7 Li (p, p ) 7 Li, 7 Li (n, n ) 7 Li, and 7 Li (p, n ) 7 Be reactions was carried out by Presser and Bass [5]. This paper describes measurements of (d, n )/(d, p ) and (p, n )/(p, p ), each over a larger energy range than was previously available, and of the excitation functions of the individual reactions.…”

Section: Introductionmentioning

confidence: 99%

Reactions leading to the first excited states ofLi7andBe7and isospin-mixed states in
Austin
¹
,
Paul
²
,
Brown
³

et al. 2019
Phys. Rev. C
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0
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Background Ratios of cross sections for mirror reactions sometimes deviate from the values expected on the basis of charge symmetry. These deviations are attributed to smoothly varying charge dependent effects (proton charge, different Q values) and to the effects of isospin mixed states in the compound nucleus. The effects are large and well known for certain positive parity states in 8 Be, but information is lacking for negative parity states.Purpose To measure the excitation functions of angle integrated cross sections for two pairs of reactions that involve 8 Be as an intermediate state:(1) 6 Li (d, p ) 7 Li (0.478 MeV) and 6 Li (d, n ) 7 Be (0.429 MeV); (2) 7 Li (p, p ) 7 Li (0.478 MeV) and 7 Li (p, n ) 7 Be (0.429 MeV). To measure the ratios of the neutron emitting and proton emitting reactions. To examine the implications for the structure of 8 Be.Method The ratios were determined by observing the isotropically emitted gamma rays from the decay of 7 Li (0.478 MeV) and 7 Be (0.429 MeV). Shell model calculations were performed for both positive and negative parity states. Results were compared to existing information.Results Ratios, usually with an accuracy of ±2%, were obtained for deuteron energies from 0.15 to 7.2 MeV and proton energies from 3.0 to 10.0 MeV. There were relatively strong deviations from expectations based on charge symmetry at the lowest deuteron energies and smaller deviations between E d = 2 and 4 MeV. There were very strong deviations for proton energies near 3 and 5.5 MeV, with strong neutron strength near 3 MeV and strong proton strength near 5 MeV. The shell model calculations were generally in good agreement for the positive parity states, and, with some exceptions, for negative parity states. There is reasonable evidence for the lowest lying 2 − T = 1 state at Ex= 20.3 MeV and for two new isospin mixed pairs, one for 2 + states near 22 MeV and another for 2 − states near 24 MeV.Conclusions The results will constrain future calculations for isospin mixed states in 8 Be.PACS numbers: 26.20.Fj, 26.30.Jk, 26.50.+x

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“…The γ -ray production cross section for the 477.6-keV transition in 7 Li is displayed in Fig. 5 along with previous experimental data from [4,5,[9][10][11][12][17][18][19]24,25,28]. For clarity, 4.…”

Section: A Experimental Datamentioning

confidence: 97%

“…These cover a neutron energy range from the threshold up to 21 MeV. In three of these experiments, by Presser and Bass [17], Smith [18], and Olsen et al [19], lithium-drifted germanium [Ge(Li)] detectors were used for detecting the γ rays. All three experiments used different reactions for neutron production and different methods for determining the neutron flux.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the 477.6-keVγ-ray production cross section following inelastic neutron scattering byLi7

et al. 2016

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Reactions 7Li + n, 7Li + p and excited states of the A = 8 system

Cited by 48 publications

References 32 publications

2009 Release of the Evaluated Nuclear Data Library (ENDL2009)

2009 Release of the Evaluated Nuclear Data Library (ENDL2009)

Reactions leading to the first excited states ofLi7andBe7and isospin-mixed states in
Austin
¹
,
Paul
²
,
Brown
³

et al. 2019
Phys. Rev. C
1
0
0
0
View full text Add to dashboard Cite

Measurement of the 477.6-keVγ-ray production cross section following inelastic neutron scattering byLi7

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Reactions 7Li + n, 7Li + p and excited states of the A = 8 system

Cited by 48 publications

References 32 publications

2009 Release of the Evaluated Nuclear Data Library (ENDL2009)

2009 Release of the Evaluated Nuclear Data Library (ENDL2009)

Reactions leading to the first excited states ofLi7andBe7and isospin-mixed states inAustin1, Paul2, Brown3 et al. 2019Phys. Rev. C1000View full textAdd to dashboardCite

Measurement of the 477.6-keVγ-ray production cross section following inelastic neutron scattering byLi7

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Reactions leading to the first excited states ofLi7andBe7and isospin-mixed states in
Austin
¹
,
Paul
²
,
Brown
³

et al. 2019
Phys. Rev. C
1
0
0
0
View full text Add to dashboard Cite