Photoneutron Cross Sections of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Ta</mml:mi></mml:mrow><mml:mrow><mml:mn>181</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Ho</mml:mi></mml:mrow><mml:mrow><mml:mn>165</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>

Bramblett, R.L.; Caldwell, J.T.; Auchampaugh, G.F.; Fultz, S. C.

doi:10.1103/physrev.129.2723

Cited by 96 publications

(55 citation statements)

References 25 publications

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“…The point is that as it follows from Table 4 the data for (,2n)/(,n) ratio obtained at Livermore for 181 Ta [18] are overestimated, although in special experiment has been carried many years before [7] and has used both neutron multiplicity sorting and induced activity also that was shown that (,2n) obtained at Livermore is quiet reliable. Therefore it was supposed (supposed only because experimental data for (,n) using induced activity data have not been obtained) that (,n) for 181 Ta also is reliable.…”

Section: New Evaluated Data Reliability and Authenticitymentioning

confidence: 98%

Total and partial photoneutron reactions cross sections – new analysis and evaluation

Ishkhanov

Orlin

Варламов

2012

EPJ Web of Conferences

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Abstract.The well-known problems of significant disagreements between partial photoneutron reactions (,n), (,2n) and (,3n) cross sections data obtained in various experiments are discussed. Using new objective criteria of data reliability it was shown that majority of data under discussion contains significant distortions because of definite shortcomings of experimental photoneutron multiplicity sorting methods used -the majority of experimental data obtained such methods are not reliable. These criteria were transitional photoneutron multiplicity functions

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Section: New Evaluated Data Reliability and Authenticitymentioning

confidence: 98%

Total and partial photoneutron reactions cross sections – new analysis and evaluation

Ishkhanov

Orlin

Варламов

2012

EPJ Web of Conferences

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“…stellar ^Tafon) 1 10 11 12 13 E [MeV] FIGURE 1. Present total photoneutron cross sections for 181 Ta (solid squares) and the data reconstructed from the Livermore data [17] and the Saclay data [18] by IAEA (open circles) [19]. The overproduction factors resulted from a sensitivity test using 14 sets of reaction rates with different nuclear parameters such as the nuclear structure properties, nuclear level density, optical potential and y strength.…”

Section: Photoproduction Of 180 Ta Mmentioning

confidence: 99%

Photoneutron Cross Sections of Astrophysical Significance

Utsunomiya¹

2007

AIP Conference Proceedings

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Presented in this paper are some of the latest measurements of photoneutron cross sections of direct relevance to the p-process nucleosynthesis in the context of the statistical model of compound nuclear reactions. We discuss the p-process origin of the rarest nuclide and the only naturally occurring isomer 180 Ta m , a serious underproduction problem of 138 La, and the nuclear level density of 180 Ta determined from the partial photoneutron cross section for 180 Ta m . As the laser-Compton scattering y ray at AIST has enabled one to directly determine (y,n) cross sections, the blackbody synchrotron radiation to be produced by a ten-Tesla superconducting wiggler at SPring-8 is expected to be a promising tool for exploring (y,a) and (y,p) reactions in the future.Most of heavy nuclides are produced by neutron capture followed by (3~ decay; either s-process or r-process [1]. However, 35 neutron-deficient nuclides (p-nuclei) from Se to Hg with rare solar abundances are bypassed by the s-process flow and shielded from the (3~ decay after the r-process. Photodisintegration of pre-existing seed nuclei of s and/or r-process origin is a primary process of producing the p-nuclei [2]. An extensive reaction network is required to describe the p-process nucleosynthesis, consisting of (y,n), (y,a) (y,p) reactions complemented by n, p, and a-captures, neutrino capture, and weak transformation (electron capture and (3 + decay) [2]. The reaction network involving some 2,000 nuclei and 20,000 reactions effectively produces the p-nuclei in a delicate balance of temperature and time-scale. A narrow temperature window of T = (1.5 -3.5) x 10 9 K is required, on the one hand, to ensure efficient photodisintegrations and prevent the photo-erosion of all the heavy nuclei to ion-peak species. On the other hand, the freeze-out of photodisintegrations on a short time-scale of the order of 1 second is also necessary. These conditions are met in the deep Oxygen and Neon-rich layers of massive stars during their explosions as type II supernovae satisfactorily [3][4][5][6][7]. Other plausible sites include pre-supernova phases of massive stars [3,4,8] or type la supernovae (see [2] for a more complete review).

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“…10 and 11, where the peak bremsstrahlung energy is effectively 2.5 below the threshold for the emission of neutrons leaving in the 5.2 MeV states, were calculated in the same way as those for the deuterium source. The spectrum produced by 27 MeV bremsstrahlung given in Fig. 12 is that measured by Firk [17].…”

mentioning

confidence: 95%

“…The measured photoneutron spectrum from 1 6 produced by 27 MeV bremsst rah lung. Due to uncertainties in the response function of the detector used in these measurements the spectrum shape below about 2 MeV is in some doubt.…”

mentioning

confidence: 99%

Study of a Halpern-type 4 [pi] neutron detector.

Gerstenberg¹

1967

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Photoneutron Cross Sections ofTa181andHo165

Cited by 96 publications

References 25 publications

Total and partial photoneutron reactions cross sections – new analysis and evaluation

Total and partial photoneutron reactions cross sections – new analysis and evaluation

Photoneutron Cross Sections of Astrophysical Significance

Study of a Halpern-type 4 [pi] neutron detector.

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