Product yields for the photo-fission of 209Bi with 2.5 GeV bremsstrahlung

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2009-06, Vol.267 (11), p.1891-1898
• Main Authors: Naik, Haladhara, Singh, Sarbjit, Reddy, Annareddy Venkat Raman, Manchanda, Vijay Kumar, Kim, Guinyun, Kim, Kyung Sook, Lee, Man-Woo, Ganesan, Srinivasan, Raj, Devesh, Lee, Hee-Seock, Oh, Young Do, Cho, Moo-Hyun, Ko, In Soo, Namkung, Won
• Format: Article
• Language: English
• Subjects: 2.5 GeV Bremsstrahlung; Catcher foil; Mass-yield distribution; Photo-fission of 209Bi
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2009.04.001

The mass-yield distribution of fission products in the 2.5 GeV bremsstrahlung-induced fission of 209Bi have been determined by using the recoil catcher and the off-line γ-spectrometry technique in the high energy electron linac at the Pohang Accelerator Laboratory. The mass-yield determination involves the measurements of cumulative yields for 32 fission products and independent yields of 17 fission products in the photo-fission of 209Bi nuclei. It was found that the mass-yield distribution of fission products in 209Bi is symmetric with an average mass of 95 ± 0.5 and a FWHM of 51 ± 2.0 mass units. Present data at 2.5 GeV along with the literature data at 1 GeV, 700–600 MeV, and 85–28 MeV were interpreted from the point of increase of multi-chance fission and multi-nucleon emission probabilities with an increase in excitation energy. It was found that the average mass of the mass-yield distribution of the fission products decreases from 103 ± 0.5 at 28–85 MeV to 95 ± 0.5 at 2.5 GeV. On the other hand, the FWHM of the mass-yield distribution increases from 19 mass units at 28–40 MeV to 51 mass units at 2.5 GeV. It was also found that the nuclear structure effect observed at the photo-fission of 209Bi with 28–85 MeV bremsstrahlung is washed out at higher energy.