β-decay half-lives of very neutron-rich Kr to Tc isotopes on the boundary of the r-process path: an indication of fast r-matter flow.
نویسندگان
چکیده
The β-decay half-lives of 38 neutron-rich isotopes from (36)Kr to (43)Tc have been measured; the half-lives of (100)Kr, (103-105)Sr, (106-108)Y, (108-110)Zr, (111,112)Nb, (112-115)Mo, and (116,117)Tc are reported here. The results when compared with previous standard models indicate an overestimation in the predicted half-lives by a factor of 2 or more in the A≈110 region. A revised model based on the second generation gross theory of β decay better predicts the measured half-lives and suggests a more rapid flow of the rapid neutron-capture process (r-matter flow) through this region than previously predicted.
منابع مشابه
test of half-life predictions for neutron-rich isotopes of refractory elements
Beta-decay gross properties of neutron-rich isotopes 104 Y and Tc produced in 25 MeV proton-induced fission of U have been measured. Decays of 104 Y with a half-life of 180"60 ms and of Tc with a half-life of 150"30 ms are 112,113,114 Ž . reported for the first time. Beta-delayed neutron emission probabilities of Tc are determined as 1.5"0.2 %, Ž . Ž . 2.1"0.3 % and 1.3"0.4 %, respectively. Com...
متن کاملβ-Decay Half-Lives of 110 Neutron-Rich Nuclei across the N=82 Shell Gap: Implications for the Mechanism and Universality of the Astrophysical r Process.
The β-decay half-lives of 110 neutron-rich isotopes of the elements from _{37}Rb to _{50}Sn were measured at the Radioactive Isotope Beam Factory. The 40 new half-lives follow robust systematics and highlight the persistence of shell effects. The new data have direct implications for r-process calculations and reinforce the notion that the second (A≈130) and the rare-earth-element (A≈160) abund...
متن کاملFirst decay study of the very neutron - rich isotope 93 Br
The decay of the mass-separated, very neutron-rich isotope 93 Br has been studied by γ-spectroscopy. A level scheme of its daughter 93 Kr has been constructed. Level energies, γ-ray branching ratios and multipolarities suggest spins and parities which are in accord with a smooth systematics of the N = 57 isotones for Z ≤ 40, suggesting the N = 56 subshell closure still to be effective in Kr iso...
متن کاملHalf-life systematics across the N=126 shell closure: role of first-forbidden transitions in the β decay of heavy neutron-rich nuclei.
This Letter reports on a systematic study of β-decay half-lives of neutron-rich nuclei around doubly magic (208)Pb. The lifetimes of the 126-neutron shell isotone (204)Pt and the neighboring (200-202)Ir, (203)Pt, (204)Au are presented together with other 19 half-lives measured during the "stopped beam" campaign of the rare isotope investigations at GSI collaboration. The results constrain the m...
متن کاملShape mixing and β-decay properties of neutron-deficient Kr and Sr isotopes
Gamow-Teller strength distributions and β-decay half-lives in neutron-deficient Kr and Sr isotopes are investigated within a deformed quasiparticle random phase approximation. The approach is based on a self-consistent Skyrme Hartree-Fock mean field with pairing correlations and residual separable particle-hole and particle-particle forces. A simple two-level model is used to mix the nuclear sh...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Physical review letters
دوره 106 5 شماره
صفحات -
تاریخ انتشار 2011