s- and p-wave neutron spectroscopy

Farrell, J.A.; Bilpuch, E.G.; Newson, H.W.

doi:10.1016/0003-4916(66)90204-1

Cited by 79 publications

(5 citation statements)

References 9 publications

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“…The range of energy analyzed is given for each reference. Up until now, there were no *°Ni capture measurements above 200 keV and the toul cross-section measurements of Farrel et al 22 were the only data available above 340 keV.…”

Section: Capture Kernelmentioning

confidence: 99%

Neutron transmission and capture measurements and analysis of /sup 60/Ni from 1 to 450 keV

Perey¹,

Harvey²,

Macklin³

et al. 1982

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High-resolution transmission and capture measurements of M Ni-enricned targets have been made at the Oak Ridge Electron Linear Accelerator (ORELA) from a few eV to 1800 keV in trarsmissior. and from 2.5 keV to 5 MeV in capture. The transmission data from I to 450 keV were analyzed with a muiti-level R-matrix code which uses the Bayes' theorem for the fitting process. This code provides the energies and neutron widths of toe resonances inside the 1-to 450-keV region as well as a possible parameterization for outside resonances to describe the smooth cross section in this region. The capture data were analyzed with a least-squares fitting code using the Breit-Wigner formula. From 2.S to 450 LeV, 166 resonances were seen in both sets of data. Correspondence between the energy scales shows a discontinuity around 300 keV which makes the matching of resonances at higher energies difficult. Eighty-nine resonances were seen in the capture data only. Average parameters for the '0 observed »wave resonances were deduced. The average level spacing D" was found to be equal to I5.2_± 1.5 keV, the strength function, S 0 , equal to (2.2 ± 0.6) X 10-4 and the average radiation width, H,, equal to 1.30 ± 0.07 eV. The staircase plot of the reduced level widths and the plot of the Lorentz-weighted strength function averaged over various energy intervals show possible evidence for doorway states. The level densities calculated with the Fermi-gas model for £ = 0 and for £ > 0 resonances were compared with the cumulative number of observed resonances, but the analysis is not conclusive. The average capture cross section as a function of the neutron incident energy is compared to the tail of the giant electric dipole resonance prediction. ? The experimental conditions of the capture measurements are given in Sect. 4 wiih a discussion of the various corrections applied to the raw data. The capture data analysis made with a least-squares fitting code using the Breit-Wigner formalism is reported in Sect. 5, Section 6 deals with problems encountered in the energy scales of the two sets of data. In Sect. 7, the resonance parameters obtained from the analysis of both data sets are reported and their uncertain ties discrised. Comparisons ?

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Section: Capture Kernelmentioning

confidence: 99%

Neutron transmission and capture measurements and analysis of /sup 60/Ni from 1 to 450 keV

Perey¹,

Harvey²,

Macklin³

et al. 1982

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“…In 64 Ni + n, 27 s-wave resonances were observed by Beer et al [20] and Farrell et al [21] below E n 580 keV as shown in Table V. Though the data are out of date, we found the frequent appearance of the factor 8 in the integer ratios Numerical data for the probability calculations are summarized in Table II.…”

Section: G 64 Ni S-wave Resonancesmentioning

confidence: 53%

Regular family structures observed in neutron resonance energies: Breathing model of the compound nucleus

Ohkubo¹

2013

Phys. Rev. C

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In neutron resonances, which are long believed to be a form of quantum chaos, simple regular family structures are found for many even-even nuclei in the several tens of keV to MeV region. Resonance energies can be written by simple arithmetic expressions with good accuracies, where separation energies S n and G play essential roles and where G ≈ 34.5 MeV is almost equal to the Fermi energy. Family structures are described for the observed resonances in 40 Ca, 54 Cr, 64 Ni, 90 Zr, and 208 Pb. Statistical probability tests are performed for the appearance of these family structures. A classical dynamic model of the compound nucleus is proposed where the recurrence of multiple oscillators produces "breathing" and seems to successfully reproduce observed resonance families.

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“…Die in [14] benutzte funktionentheoretische Methode scheint bisher nur im Fall eines lokalen Potentials ausgenutzt worden zu sein. Ihre Anwendbarkeit im nichtlokalen Fall beruht wesentlich auf der Konstruktion (2) der vohtiindigen GREEN-Funktion und auf der Kenntnis der Eigenschaften des Resolventenkerns R,(k).…”

Section: Grundlegende Formeln Und Satzeunclassified

“…Sobald man die nichtrelativistische Streuung zweier Teilchen, von denen mindestens eins eine innere Strukturwie zum Beispiel ein Atomkerna dweist, mit der SCHRODINGER-Gleichung beschreiben will, wird also die Verwendung von nichtlokalen Potentialen unumglnglich. Zum Beispiel bei der Streuung von Neutronen an einem Atomkern kann man zwar den gemittelten Wirkungsquerschnitt durch ein lokales Potential in der SCHRODINaER-Gleichung wiedergeben, nicht aber die sehr scharfen Maxima im Wirkungsquerschnitt, die man bei besserer Energieauflosung der Apparate beobachten kann [l], [2]. Aber schon die Wechselwirkung zwischen zwei Nukleonen scheint nichtlokal zu sein [3], [4].…”

Section: Introductionunclassified

Die SCHRöDINGER-Gleichung mit nichtlokalem Potential. I. Die Resolvente

Heydt

1973

Ann. Phys.

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For a wide class of nonlocal potenthls the SCERODINGEB integro-differential equations for the radial waves may be reduced to integral equations containing D-kernels. Therefore a number of analytic and functional-analytic properties of the resolvent of the radial wave equation may be deduced by meansof the FREDHOLW method. Thence, the completeness of the physical radial wave functions, among other things, is proved by a known method. The positive-energy bound states occurring with nonlocal potentials are interpreted as resonances of vanishing width. We consider the non-imaginary "resonance poles" of the resolvent in a strip 0 > Im k > -a of the complex k-plane 1/a being the range of the potential. The structure of the principal parts is specified. The results will be used in the second part of this article').

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s- and p-wave neutron spectroscopy

Cited by 79 publications

References 9 publications

Neutron transmission and capture measurements and analysis of /sup 60/Ni from 1 to 450 keV

Neutron transmission and capture measurements and analysis of /sup 60/Ni from 1 to 450 keV

Regular family structures observed in neutron resonance energies: Breathing model of the compound nucleus

Die SCHRöDINGER-Gleichung mit nichtlokalem Potential. I. Die Resolvente

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