Angular distributions and cross sections of the photoneutron reaction in 9Be in the photon energy region 18–26 MeV

1977 ◽  
Vol 55 (4) ◽  
pp. 364-369 ◽  
Author(s):  
A. Buchnea ◽  
R. G. Johnson ◽  
K. G. McNeill
Keyword(s):  
Cross Section ◽  
Photon Energy ◽  
Cross Sections ◽  
Energy Region ◽  
Angular Distributions ◽  
Photoneutron Reaction ◽  
Integrated Cross Section

The 9Be(γ,n0)8Be and 9Be(γ,n1)8Be reactions were studied in the photon energy region 18 to 26 MeV. The integrated cross section of the (γ,n0) reaction was found to be less than 0.1 MeV mb in this energy region. The integrated cross section for the (γ,n1) reaction in the energy region is 2.4 ± 0.4 MeV mb, which is 10 to 15% of the total photoneutron cross section. The measured angular distributions for the (γ,n1) reaction are consistent with the population of 3/2+ and 5/2+ states of 9Be. These results are consistent with slightly re-interpreted predictions of Majling, Kukulin, and Smirnov.

THE (γ, n) AND (γ, p) CROSS SECTIONS OF ARGON40

1954 ◽  
Vol 32 (9) ◽  
pp. 593-598 ◽  
Author(s):  
D. McPherson ◽  
E. Pederson ◽  
L. Katz
Keyword(s):  
Cross Section ◽  
Photon Energy ◽  
Cross Sections ◽  
Integrated Cross Section ◽  
Peak Value

The (γ, n) and (γ, p) cross sections in A40 have been measured as a function of photon energy from threshold to 24 Mev. The (γ, n) cross section was found to have a peak value of 38 mbarns at 20 Mev. and an integrated cross section of 0.35 Mev-barn. These values for the (γ, p) cross section were found to be 120 mbarns at > 25 Mev. and 0.54 Mev-barn respectively. In spite of the higher (γ, p) threshold, it was found that the two cross sections were equal at 19.5 Mev. and above this energy the (γ, p) cross section became larger. This interesting result is discussed.

Alpha particles from the photodisintegration of 9Be in the photon energy region 18 to 26 MeV

1978 ◽  
Vol 56 (1) ◽  
pp. 47-51 ◽  
Author(s):  
A. Buchnea ◽  
R. G. Johnson ◽  
K. G. McNeill
Keyword(s):  
Cross Section ◽  
Photon Energy ◽  
Energy Region ◽  
Alpha Particles ◽  
Upper Limit ◽  
Major Reaction ◽  
Reaction Channels ◽  
Integrated Cross Section

Alpha particles from the 9Be(γ,n)8Be(16.6) and 9Be(γ,α0)5He reactions were studied in the photon energy region 18 to 26 MeV; the results yielded a combined integrated cross section of 13.1 ± 2 MeV mb and an upper limit on the integrated (γ,α0) cross section of 4.0 MeV mb. This agrees within error with the integrated cross section of Becchi, Meneghetti, Sanzone, and Vitale, 10 ± 2 MeV mb, which would contain about 50% of any contribution from the (γ,α0) reaction. These reactions together with the 9Be(γ,n1)8Be reaction (which has an integrated cross section of 2.4 ± 0.4 MeV mb) are the major reaction channels contributing to the total photoneutron cross section in this energy region. Their sum, 15.5 MeV mb, agrees well with the results of Nathans and Halpern and Hughes, Sambell, Muirhead, and Spicer but disagrees with that of Costa, Pasqualini, Piragino, and Roasio.

scholarly journals Absolute cross section measurements of 238U(n,f) and 237Np(n,f) in the neutron energy range 1-2.4 MeV

2019 ◽  
Vol 211 ◽  
pp. 03009
Author(s):  
Paula Salvador-Castiñeira ◽  
Franz-Josef Hambsch ◽  
Alf Göök ◽  
Marzio Vidali ◽  
Nigel P. Hawkes ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Energy ◽  
Cross Sections ◽  
Energy Region ◽  
Power Plants ◽  
National Physical Laboratory ◽  
Absolute Cross Section ◽  
Neutron Energy Range ◽  
Physical Laboratory ◽  
Low Energies

New standard (n,f) cross sections other than 235U are important to study the relevant cross sections for Generation-IV power plants. A specific need for such standards is for performing new experiments with quasimonoenergetic neutron beams, such as those produced by Van de Graaf accelerators. Neutrons down-scattered to low energies in the experimental environment, so called room-return, become relevant for this type of measurements. Hence, a standard (n,f) cross section with a fission threshold is of great interest, in order to suppress the contribution from room-return background. For this reason we have performed two experiments at the VDG of the National Physical Laboratory to measure absolutely the (n,f) cross sections of 235U, 238U and 237Np in the fast neutron energy region. Our preliminary results are in agreement with the most up-to-date evaluations.

Electron loss cross sections from rare gas atoms to Ar+

1982 ◽  
Vol 60 (7) ◽  
pp. 977-980
Author(s):  
B. Hird ◽  
S. P. Ali
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Energy Region ◽  
Rare Gas ◽  
Electron Loss ◽  
Rare Gases ◽  
Thin Target ◽  
Rare Gas Atoms ◽  
Good Agreement

Measurements of the σ10 cross section for a beam of Ar+ ions of energies between 30 and 120 keV passing through a thin target of the rare gases show good agreement with the few previous measurements in this energy region.

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.

THE SCATTERING OF PROTONS ON 7Li, 9Be, AND 12C AT 100 MEV

1966 ◽  
Vol 44 (12) ◽  
pp. 2961-2971 ◽  
Author(s):  
S. K. Mark ◽  
P. M. Portner ◽  
R. B. Moore
Keyword(s):  
Angular Distribution ◽  
Inelastic Scattering ◽  
Cross Sections ◽  
Differential Cross ◽  
Target Nucleus ◽  
Energy Region ◽  
Angular Distributions ◽  
Angular Range ◽  
Existing Data ◽  
Octupole Excitation

Elastic and inelastic scattering of protons on 7Li, 9Be, and 12C have been studied, using the 100-MeV proton beam from the McGill synchrocyclotron. Differential cross sections for the various groups of scattered protons were measured over an angular range of 5° to 90° (lab). For proton groups resulting from a quadrupole excitation in the target nucleus, the angular distribution was found to increase at scattering angles less than 10°. Angular distributions corresponding to an octupole excitation were observed to decrease at small angles. The results have been compared with existing data in this energy region.

scholarly journals Analysis of cross sections on iron and oxygen using Cf-252 neutron source

2020 ◽  
Vol 239 ◽  
pp. 18005
Author(s):  
Bohumil Jansky ◽  
Jiri Rejchrt ◽  
Evzen Novak ◽  
Anatoly Blokhin
Keyword(s):  
Cross Section ◽  
Neutron Source ◽  
Neutron Spectrum ◽  
Heavy Water ◽  
Cross Sections ◽  
Energy Region ◽  
Nuclear Data ◽  
Data Section ◽  
Neutron Spectra ◽  
Artificial Changes

The leakage neutron spectra measurements have been done on benchmark spherical assemblies with Cf-252 source in center of 1) heavy water sphere with diameter of 30 cm (with Cd cover) and of 2) iron spheres with diameter of 100 cm and 50 cm. It has been stated for years that transport calculations by iron overestimate measured spectra in energy region around 300 keV by about 20-40 % (calculation to measurement ratio C/E = 1.2-1.4). The influence of an artificial changes in cross-section XS-Fe-56 (n,elastic)designed by IAEA, Nuclear Data Section, has been studied on the iron spheres. Influence of those XS-corrections to calculated neutron spectrum is presented.

scholarly journals Coherent neutrino scattering off the 48Ti nucleus

2012 ◽  
Vol 20 ◽  
pp. 104
Author(s):  
D. K. Papoulias ◽  
T. S. Kosmas
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Energy Region ◽  
Decomposition Method ◽  
Form Factors ◽  
Momentum Dependence ◽  
Neutrino Scattering ◽  
Neutrino Detection ◽  
Supernova Neutrino ◽  
Coherent Neutrino Scattering

The method of fractional occupation probabilities of the orbits is adopted in order to obtain nuclear form factors to be used for reliable cross sections calculations of the dominant coherent neutrino-nucleus reaction channel. To this purpose, the multipole decomposition method of Donnelly-Walecka is employed. The response of the 48Ti nucleus in solar and Supernova neutrino detection is investigated through our realistic nuclear structure cross sections calculations, based on the solution of the BCS equations. The present results indicate that the momentum dependence of the nuclear form factors cannot be neglected from the cross section, especially in the energy region of Supernova neutrinos (or for neutrinos having higher energies), because differences of even orders of magnitude may occur.

On discrepancies in atomic photoeffect cross sections in the low photon energy region

2000 ◽  
Vol 53 (4-5) ◽  
pp. 949-952 ◽  
Author(s):  
V.R.K Murty ◽  
K.R.S Devan ◽  
D.P Winkoun
Keyword(s):  
Photon Energy ◽  
Cross Sections ◽  
Energy Region
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