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β-delayed proton decays of Tz = 1/2 series nuclei81Zr and85Mo have been studied in detail by using p-γ coincidence measurement. The β-delayed proton spectra populating the first excited states of the daughter nuclei have been obtained. Half-life of81Zr has been measured tobe5.3s ± 0.5 s and that of85Mo 3.2 s ± 0.2 S. By using statistical model calculations and systematic analyses, spins and parities for the ground states of81Zr and85Mo have been tentatively assigned to be 3/2− and 1/2−, respectively. Mass excess of81Zris -58.3 MeV± 0.2 MeV and that of85Mo-59.1 MeV ± 0.4 MeV. Combining the measured half-lives with the calculated partial ones yields the branches of β-de-layed proton decay for81zr and85Mo of (1.2 ± 0.2) × 10-3 and (1.4 ± 0.2) × 10-3, respectively. [ABSTRACT FROM AUTHOR]

The nuclideCe was produced by a (O, 4 n) reaction on an enrichedSn target. Reaction products were transported to a shielded location by using a heliumjet tape transport system. A 22.9 min activity in chemically separated cerium sample was identified asCe. The (EC+ β ) decay scheme ofCe was proposed for the first time. This scheme includes 108 γ-lines, 107 γ-lines among them being new. More than 13 1 low-lying states ofLa are populated in the decay ofCe. Two new isomers with half-life of 77±10 ns and 17±5 ns were observed by means of delayed γ-γ coincidence measurements. [ABSTRACT FROM AUTHOR]

Unknown β-delayed proton precursor121Ce was produced via the reaction of92Mo(32S, 3n), and identified by an He-jet fast tape transport system with “P-γ” coincidence measurements. The half-life of121Ce decay was determined to be (1.1 ± 0. l)s. Its energy spectrum of β-delayed protons was measured and the β-delayed proton branching ratio for121decay was roughly estimated to be ∼ 1 %. After β-delayed proton decay of the precursors119Ba,121Ba and122La, some of γ-transitions from low-lying states to the ground states in their “daughters” were observed for the first time. [ABSTRACT FROM AUTHOR]

The decay of20Na of astrophysical reactions has been studied deeply via20Ne(p, n)20Na reaction. A new β-delayed α decay with α energy of 5 896 ± 6 keV and relative intensity of 0.002 4 ± 0. 000 3 was discovered. At the same time the16O recoiling in β+-delayed α decay of20Na was observed in experiment for the first time. From these, it is inferred that a β-delayed low energy α decay of20Na with energy of ∼780 keV and relative intensity of ∼1.4 was mixed in16O recoiling. In16O recoiling and the low energy α decay, the energy loss for low energy charged particles through matter was discussed in detail. At last, two methods for discriminating the β-delayed low energy α decay of20Na were proposed. [ABSTRACT FROM AUTHOR]

A new transuranium neutron-deficient isotope235Am was produced by 35 MeV proton to bombard the rare radioactive238Pu target. The products were transported and collected by the He-jet system. The Am isotopes were separated and purified by radiochemistry method and the y-ray, X-ray and y-X(y) coincidence of the samples was measured. The synthesis of235Am was definitely identified. Its measured half-life is (15±5) min. [ABSTRACT FROM AUTHOR]

Unknown β-delayed proton precursorGd has been synthesized by the reactionCd (S, 3n) and identified using a helium-jet recoil fast tape-transport system with a γ(X)-p coincidence measurements. Its β-delayed proton spectrum has been observed. The half-life ofGd decay has been determined to be 1.1±0.2 s. [ABSTRACT FROM AUTHOR]

Fr has been produced by irradiation ofAu withO,and studied using a He-jet recoil tape transport system.A decay scheme is proposed for the first time,based on X-γ and γ-γ coincidence measurements,which takes account of 20 observed γ-rays. The branching ratio for (EC+ β ) decay ofFr has been estimated to be 3.0±1.5%. Five members of low-lying states inRn can be explained with the configuration [(Rn 2)( νf5/2)]. [ABSTRACT FROM AUTHOR]