Photoneutron reaction cross sections for 75As and 181Ta: Sytematic uncertainties and data reliability

There is well-known problem of significant systematic disagreements between data for reactions (γ, 1n), (γ, 2n), obtained at Livermore (USA) and Saclay (France) using the method of photoneutron multiplicity sorting. The averaged ratios RS/Lint of integrated cross sections obtained at Saclay and Livermore for 19 nuclei from 51V to 239U are equal to 0.84 for (γ, 2n) and 1.07 for (γ, 1n) reactions. For 75As RS/Lint ratios for both partial reactions are very close (1.22 and 1.21) but for 181Ta - are quite different (0.89 and 1.25). Using the objective physical data reliability criteria it was found that there are serious doubts in reliability of Saclay and Livermore data. The newly evaluated reliable cross sections disagree with experimental data. In addition to unreliable sorting of many neutrons between both partial reactions many neutrons were lost - on the case of 181Ta in 1n channel, in the case of 75As in both 1n and 2n channels.

Theoretical photoneutron cross-section calculations on Osmium isotopes by Talys and Empire codes

In this study, the level density parameter and the gamma ray strength function effects on photoneutron reaction cross-section calculations for Osmium isotopes were investigated by employing available level density models and gamma ray strength functions within Talys v1.8 and Empire v3.1 nuclear codes. A relative variance analysis was done to determine the best gamma ray strength function. Then, the effect of level density models for the photoneutron reactions was investigated by using the best gamma ray strength function. The results were compared with each other and also with the experimental data taken from the literature.

Photoneutron Reaction Data for Nuclear Physics and Astrophysics

We discuss the role of photoneutron reaction data in nuclear physics and astrophysics in conjunction with the Coordinated Research Project of the International Atomic Energy Agency with the code F41032 (IAEA-CRP F41032).