Angular distribution effect on the integrated cross section for radiative capture of 14 MeV neutrons

✍ Scribed by F. Cvelbar; A. Likar; T. Vidmar

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 396 KB
• Volume: 645
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/s0375-9474(98)00609-5

✦ Synopsis

In the past, many reported integrated cross sections for the 14 MeV neutron radiative capture were measured at 90 ° relative to the neutron beam direction and multiplied by 47r, so as to obtain a measure of the angle-integrated cross sections.

In such a procedure, an isotropic angular distribution of y-rays is assumed. We calculated this distribution using the consistent direct-semi-direct model, in which the need for the model-free parameters has been eliminated. The result is that the al Legendre polynomial, averaged over the bound state transitions, is practically zero (distribution is forward-backward symmetric) and that the a2 coefficient is a smooth function of the mass number with the values between -0.4 and -0.6, indicating anisotropy of the distribution. Reported integrated cross sections are therefore for about 20% to 30% too high relative to the properly angle integrated cross sections. (~ 1999 Elsevier Science B.V.