Discovery of Long - Lived Shape Isomeric States which Decay by Strongly Retarded High - Energy Particle Radioactivity
نویسندگان
چکیده
The reaction 28 Si + 181 Ta has been studied at E Lab =125 and 135 MeV. Coincidences between high energy particles and various X-and γ-rays from abnormally long-lived states were observed. e.g. 7.8-8.6 MeV α-particles with γ-rays of a superdeformed band, 5.1-5.5 MeV α-particles with X-and γ-rays of W, Re, and Pt, and 3.88 MeV particles (interpreted as protons) with 185.8 keV γ-rays. The data are interpreted in terms of the production of long-lived (t 1/2 of several months) high spin isomeric states in the second well of the potential in the parent nuclei, which decay to the normal states in the daughters, and in the third well of the potential, which decay to the second well.
منابع مشابه
Strongly Enhanced Low Energy α-Particle Decay in Heavy Actinide Nuclei and Long-Lived Superdeformed and Hyperdeformed Isomeric States
Relatively low energy and very enhanced α-particle groups have been observed in various actinide fractions produced via secondary reactions in a CERN W target which had been irradiated with 24-GeV protons. In particular, 5.14, 5.27 and 5.53 MeV α-particle groups with corresponding half-lives of 3.8±1.0 y, 625±84 d and 26±7 d, have been seen in Bk, Es and Lr-No sources, respectively. The measure...
متن کاملAbnormal Radioactive Decays out of Long-Lived Super- and Hyper-Deformed Isomeric States
Long-lived high-spin superand hyper-deformed isomeric states, which exhibit themselves by abnormal radioactive decays, have been observed using the O + Au and Si + Ta reactions. They make it possible to understand the production, via secondary reactions, of the long-lived superheavy element with Z = 112 and of the abnormally low energy and very enhanced α-particles seen in various actinide sour...
متن کاملYrast three - quasiparticle K isomers in neutron - rich 181 Hf
Long-lived isomeric states in nuclei are unique laboratories for studying the detailed properties of nuclear wave functions. From an experimental standpoint, transitions deexciting long-lived isomers provide clean information on wave-function admixtures, since a better signal-to-noise ratio is achieved if short-lived excitations are allowed to decay away. From a theoretical perspective, a long-...
متن کاملResearch on isomer decay with the NEPTUNE spectrometer
A new spectrometer has been built at the EC-JRC IRMM to investigate isomer decay in the millisecond range and activation cross sections of isotopes, where isomeric states exist and are populated. The spectrometer is equipped with high-resolution gamma-ray detectors and an ionisation chamber for the measurement of charged particles, e.g., fission fragments. NEPTUNE provides pulsed quasi mono-ene...
متن کاملFavored configurations for four-quasiparticle K isomerism in the heaviest nuclei
Configuration-constrained potential-energy-surface calculations are performed including β6 deformation to investigate high-K isomeric states in nuclei around 254No and 270Ds, the heaviest nuclei where there have been some observations of two-quasiparticle isomers, while data for four-quasiparticle isomers are scarce. We predict the prevalent occurrence of four-quasiparticle isomeric states in t...
متن کامل