The “isomeric shelf” in the deep subbarrier photofission of 238U

✍ Scribed by J. Drexler; R.D. Heil; K. Huber; U. Kneissl; G. Mank; R. Ratzek; H. Ries; T. Weber; W. Wilke; B. Fischer; H. Hollick

• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 543 KB
• Volume: 437
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/s0375-9474(85)90087-9

✦ Synopsis

Time distributions of fission fragments from subbarrier photofission of 238U have been measured using a pulsed bremsstrahlung beam (E as = 3.994.3 MeV). The observed half-life of 238mU (T,,, = 155+33 ns) is in good agreement with previous results obtained at higher photon energies. The measured yield ratio of isomeric to prompt fission (I&/Y,, 2 1) directly demonstrates for the first time the overwhelming contribution of the isomeric fission in the energy range of the so-called "isomeric shelf'. The results are compared with the most recent calculations. E NUCLEAR REACTIONS "'U(y,F); E = 3.943 MeV bremsstrahlung; measured 'Fi,*, isomeric to prompt yield ratio. Depleted targets.