Photoneutrons from 19F

1976 ◽  
Vol 54 (11) ◽  
pp. 1178-1189 ◽  
Author(s):  
N. K. Sherman ◽  
K. H. Lokan ◽  
R. W. Gellie
Keyword(s):  
Excited States ◽  
Cross Section ◽  
Electric Dipole ◽  
Ground State ◽  
Time Of Flight ◽  
Branching Ratios ◽  
Integrated Cross Section ◽  
Time Of Flight Method

The 19F(γ,n) reaction was studied by irradiating teflon with bremsstrahlung of energy increasing from 13 MeV to 21 MeV in 1 MeV steps. Photoneutron spectra were measured by the time-of-flight method. Excited states of 19F at 12.10, 12.38, 13.82, and 16.24 MeV were observed. The total integrated cross section between 11.9 and 17.9 MeV was found to be (14.4 ± 2.2) MeV mb. Branching ratios to the first group of excited states of 18F compared to the ground state were measured, along with resonance widths and approximate radiative widths. They are consistent with the interpretation that all four states arise from electric dipole d → f valence transitions, with the first two states having Jπ = 1/2−, and the second two having 3/2−.

Photoneutrons from 20Ne

1975 ◽  
Vol 53 (8) ◽  
pp. 795-801 ◽  
Author(s):  
J. G. Woodworth ◽  
J. W. Jury ◽  
K. H. Lokan ◽  
N. K. Sherman
Keyword(s):  
Excited States ◽  
Cross Section ◽  
Ground State ◽  
Giant Dipole Resonance ◽  
Time Of Flight ◽  
Photon Absorption ◽  
Absolute Cross Section ◽  
Energy Distributions ◽  
Dipole Resonance ◽  
Integrated Cross Section

Photoneutron energy distributions from a target of liquid neon have been measured at 90° by time of flight for bremsstrahlung endpoint energies increasing in 1 MeV steps from 19 to 32 MeV. The differential ground state cross section for the major (91%) isotope 20Ne has been obtained, together with an estimate of the strength of transitions to excited states of 19Ne. Six photoneutron groups are observed, reflecting photon absorption which correlates excellently with existing photoproton data, although the absolute cross section is about 10% smaller.It is noted that the giant dipole resonance, estimated by combining the photoneutron and photoproton data, is centered at approximately 20 MeV, which is anomalously low, and that the integrated cross section up to 28 MeV exhausts only half of the dipole sum.

Photoneutron Cross Sections in 14N

1972 ◽  
Vol 50 (15) ◽  
pp. 1689-1696 ◽  
Author(s):  
R. W. Gellie ◽  
K. H. Lokan ◽  
N. K. Sherman ◽  
R. G. Johnson ◽  
J. I. Lodge
Keyword(s):  
Excited States ◽  
Cross Section ◽  
Cross Sections ◽  
Neutron Emission ◽  
Giant Resonance ◽  
Sequential Decay ◽  
Dipole Resonance ◽  
Intermediate States ◽  
Integrated Cross Section ◽  
High Degree

Photoneutron distributions from 14N have been obtained by time-of-flight methods, for bremsstrahlung end-point energies increasing in 2 MeV steps from 15.5 to 29.5 MeV. A large part of the neutron yield is associated with the sequential decay of 14N to 12C, through well-defined intermediate states of 13C, at 7.55, 8.86, and 11.80 MeV, which are unstable against neutron emission. The (γ,n0) cross section for neutron emission to the ground state of 13N is found to agree very closely with the corresponding (γ,p0) cross section, implying a high degree of isospin purity for the giant dipole resonance of 14N. It is observed that the decay of the giant resonance proceeds freely through those odd-parity excited states of the A = 13 nuclei which are single hole states formed by the removal of a p-shell nucleon from the parent 14N.The integrated cross section for all neutron-producing interactions is found to be 88 ± 5 MeV mb.

1s hole excited states of Be: partial autoionization rates compared with recent experimental data

1991 ◽  
Vol 69 (5) ◽  
pp. 603-605
Author(s):  
D. Petrini ◽  
J. A. Tully
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Cross Section ◽  
Ground State ◽  
Photoionization Cross Section ◽  
Recent Experimental Data ◽  
Auger Decay ◽  
Close Coupling ◽  
University College London ◽  
The University

Auger decay following inner-shell photoexcitation of atomic beryllium is studied using the University College London close-coupling codes. We reproduce some of the features observed experimentally by Krause and co-workers. The vastly predominant decay mode of Be 1s2s2np1P° is to Be+ 1s2np rather than the ground state of Be+ and the theoretical np/2s ratio agrees with the experimental value. The peak observed in the partial photoionization cross section for formation of 1s(2s2p3P) 2P° is due to photoexcitation of 1s2s(3s3p3P) 1P° followed by autoionization. Our theoretical result reproduces this feature. Strong configuration interaction effects limit the accuracy we can achieve for the radiationless decay width.

Neutron Capture Cross-Section Measurement of Rhodium in the Energy Region from 0.003 eV to 80 keV by Linac Time-of-Flight Method

2003 ◽  
Vol 144 (1) ◽  
pp. 94-107 ◽  
Author(s):  
Samyol Lee ◽  
Shuji Yamamoto ◽  
Katsuhei Kobayashi ◽  
Guinyun Kim ◽  
Jonghwa Chang
Keyword(s):  
Cross Section ◽  
Neutron Capture ◽  
Energy Region ◽  
Capture Cross Section ◽  
Time Of Flight ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Cross Section Measurement ◽  
Section Measurement ◽  
Time Of Flight Method

Measurements of neutron induced fission cross-section for 242mAm from 0.003 eV to 10 keV using lead slowing-down spectrometer, thermal neutron facility and time-of-flight method

2001 ◽  
Vol 28 (8) ◽  
pp. 723-739 ◽  
Author(s):  
Tetsuya Kai ◽  
Katsuhei Kobayashi ◽  
Shuji Yamamoto ◽  
Hyun-Je Cho ◽  
Yoshiaki Fujita ◽  
...  
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Time Of Flight ◽  
Fission Cross Section ◽  
Slowing Down ◽  
Induced Fission ◽  
Neutron Facility ◽  
Time Of Flight Method

Measurement of Neutron Capture Cross Section of237Np by Linac Time-of-Flight Method and with Linac-driven Lead Slowing-down Spectrometer

2002 ◽  
Vol 39 (2) ◽  
pp. 111-119 ◽  
Author(s):  
Katsuhei KOBAYASHI ◽  
Samyol LEE ◽  
Shuji YAMAMOTO ◽  
Hyun Je CHO ◽  
Yoshiaki FUJITA
Keyword(s):  
Cross Section ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
Time Of Flight ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Slowing Down ◽  
Time Of Flight Method

scholarly journals Neutron total cross section measurements of polyethylene using time-of-flight method at KURNS-LINAC

2019 ◽  
Vol 57 (1) ◽  
pp. 1-8
Author(s):  
Jaehong Lee ◽  
Jun Nishiyama ◽  
Jun-Ichi Hori ◽  
Rei Kimura ◽  
Takayuki Sako ◽  
...  
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Time Of Flight ◽  
Neutron Total Cross Section ◽  
Time Of Flight Method

Vibronically induced Jahn–Teller progressions in the electronic spectrum of iridium hexafluoride

1968 ◽  
Vol 46 (15) ◽  
pp. 1721-1724 ◽  
Author(s):  
J. C. D. Brand ◽  
G. L. Goodman
Keyword(s):  
Electronic Spectrum ◽  
Excited States ◽  
Electric Dipole ◽  
Ground State ◽  
Electronic States ◽  
Electronic Transitions ◽  
Electrostatic Forces ◽  
First Approximation ◽  
Jahn Teller

The absorption of IrF6 vapor between 0.7 and 1.3 μ consists of three distinct electronic transitions connecting the Γ8g ground state with higher Γ6g, Γ8g, and Γ7g states of the (5d f2g)3 configuration. In first approximation, Jahn–Teller forces vanish in the two Γ8g states, while the Γ6g and Γ7g states involve Kramers magnetic degeneracy, which cannot be split by electrostatic forces. Accordingly, no splittings of the ν2(eg) or ν5(f2g) excited states are observed in these spectra, but short progressions in ν5 do appear in the electric-dipole-allowed, vibronic parts of these transitions. These progressions are considered to show that Jahn–Teller anharmonicity can be induced by admixtures of odd-parity, orbitally degenerate electronic states, i.e. by the same mechanism through which these transitions derive their electric-dipole intensity.

scholarly journals Neutron Capture Cross Section Measurements of Tc-99 and Rh at Energies below 40 keV by Linac Time-of-Flight Method

2002 ◽  
Vol 39 (sup2) ◽  
pp. 214-217 ◽  
Author(s):  
Katsuhei Kobayashi ◽  
Samyol Lee ◽  
Shuji Yamamoto ◽  
Takaaki Yoshimoto ◽  
Yoshiaki Fujita ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
Time Of Flight ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Time Of Flight Method
Sign in / Sign up

Export Citation Format

Share Document