0000000000328423
AUTHOR
K. Vierinen
Beta-delayed particle emission of 36K
Abstract 36 Ar targets of 19 μg cm 2 thickness were made by a sandwich technique in which a 70 nm layer of Al was evaporated onto the implanted Al surface between five successive implantations of 36 Ar ions. The sources of 36 K were prepared by depositing the recoil atoms from the 36 Ar(p, n) 36 K reaction by means of a helium jet onto a fast transport tape. The measured delayed particle spectra revealed 11 proton groups (0.5 MeV E p E α 36 K. Total proton and α-particle branching ratios were measured to be 4.8 × 10 −4 and 3 × 10 −5 , respectively. Partial level widths and reduced proton and α-particle transition widths were determined for several individual levels with the aid of additiona…
Studies of Weak Beta-Delayed Protons Emitted in the Decay of Odd-Z, Tz = -3/2 Nuclei
Radioactive decay of Tz = - 3/2 nuclides, 27P and 31Cl, predicted to be weak β-delayed proton precursors, have been looked for. Two proton groups having energies of 989 ± 15 and 1528 ± 20 keV and a half-life of 150 ± 25 ms were associated with the decay of 31Cl. The search for 27P is still under way, but the first qualitative results are briefly discussed.
Submillisecond On-Line Mass Separation of Nonvolatile Radioactive Elements: An Application of Charge Exchange and Thermalization Processes of Primary Recoil Ions in Helium
Transportation of thermalized primary recoil ions from nuclear reactions by helium flow has been investigated as a means of injecting short-lived radioactive nuclides into an on-line isotope separator. Several short-lived radioactive isotopes of highly nonvolatile elements such as B, Sc, Nb, and W have been separated. The efficiency for heavy nuclides with half-lives above 1 ms is between 1 and 10%. The shortest-lived activity identified in an on-line separation is the 182-\ensuremath{\mu}s isomeric state in $^{207}\mathrm{Bi}$.
Beta decay of 40Sc to proton and alpha-particle unbound states in 40Ca
Delayed charged particle emission associated with the precursor nuclide 40Sc was studied by use of the He-jet technique. Altogether 40 proton groups (1.0 MeV < Ep < 3.7 MeV) and 21 α-particle groups (2.0 MeV < Eα < 4.6 MeV) were observed. Total proton and α-particle branching ratios were measured to be (4.4±0.7) × 10−3 and (0.17±0.05) × 10−3, respectively. Association of the delayed particle emitting levels with the levels observed in resonance reaction studies is discussed. The fact that the most prominent α-particle groups do not have a counterpart in resonance reaction data suggests collectivity or a cluster configuration for the emitting levels. Log ft values (upper limits) for β+ trans…