New nucleide actinium-231
Abstract
A new nucleide actinium-231 was identified from the reaction of Th232(γ, p)Ac231 induced by the 25-MeV bremsstrahlung. The activity was chemically separated from fission products with the aid of a recoil method. The half-life of this new isotope was found to be and the end-point energy of the beta ray was Eβ = 2.1±0.1 MeV. Several weak gamma rays were also observed.
References (6)
- K. Takahashi et al.
Nuclear Physics
(1960) - H. Morinaga et al.
Nuclear Instruments and Methods
(1959) - S.A.E. Johansson
Arkiv Fysik
(1956)
Cited by (9)
Nuclear Structure and Decay Data for A=231 Isobars
2022, Nuclear Data SheetsThe present evaluation of currently known nine nuclides of A=231: (231Rn, 233Fr, 231Ra, 231Ac, 231Th, 231Pa, 231U, 231Np and 231Pu) represents an update and revision of previous A=231 evaluation by 2013Br04. All the known decay and reaction data are evaluated, with recommended properties given in the Adopted Levels, Gammas datasets, for gamma-ray energies, photon branching ratios, level half-lives, spins, parities, transition probabilities, and configuration assignments. For 231Rn, only an identification of the nuclide has been made without an experimental determination of its half-life. For 231Fr, no excited states are known. About 30 levels in 231Ra up to 1774 keV excitation are known only from β− decay of 231Fr with level half-lives determined for five excited states. For 231Ac, excited states up to 3122 keV are known from β− decay, (t,α), and fragmentary information for high-spin levels from two heavy-ion reaction studies, with lifetimes of excited states measured for five levels. Extensive structure and rotational band information for 231Th is available for a large number of levels up to 1714 keV from β− and α decays, (n,γ) thermal and resonance, single-particle transfer reactions (d,p), (d,t) and (3He,α), with limited data for high-spin levels from one secondary reference, and half-lives available for five excited states. Very detailed structure data are available for 231Pa up to 2139 keV from β−, ε and α decays, (α,t), (d,d′) and high-spin data from heavy-ion Coulomb excitation and (p,2nγ) reaction, with level half-lives known for 34 excited states, mostly deduced by evaluators from transition probabilities determined in Coulomb excitation. Only eight excited states are known in 231U up to 1268 keV from ε and α decays, with no data for half-lives of excited states. For 231Np and 231Pu, only the ground-state is known from α decays, with a tentative level at 324 keV in 231Pu. Measurements of nuclear rms charge radius and isotope shifts for 231Ra have been made by 2018Ly01, and that for rms charge radius for 231Fr by 2014Bu06.
235U is a well known nuclide for nuclear structure and reactor applications. There have been a large number of studies of its alpha decay to levels in 231Th, including some recent ones such as 2018Ma03 and 2017Le03, yet evaluators' analysis of the decay scheme suggests that, while α-particle transitions are well established, but several issues still remain about intricacies of gamma-ray and conversion electron spectroscopy which need to be resolved through dedicated experiments for a complete understanding of the decay scheme characteristics, although, this sort of research project would seem a challenging spectroscopic problem. As commented in individual datasets for other decays, important spectral information is lacking for most of the decay schemes, with almost no information available for some of these, resulting in many incomplete decay schemes in A=231 mass chain.
Nuclear Data Sheets for A = 231
2013, Nuclear Data SheetsSpectroscopic data for all nuclei with mass number have been evaluated, and the corresponding level schemes from radioactive decay and reaction studies are presented.
Highlights of this evaluation include:
A new interpretation of γ–ray spectroscopic results measured with the GAMMASPHERE spectrometer (2002AbZV, 2000JaZY, 1999Br17) has established the level structure of the ground state rotational band up to spin/parity in 231Ac.
Precise measurements of energies and cross sections of scattered tritons from the 232Th(d,t) reaction has produced or confirmed the identification of several rotational bands in 231Th.
The alpha hindrance factors (HF) presented in this evaluation were calculated using values of the radius parameter interpolated from those for even–even adjacent nuclei given in 1998Ak04.
The Limitation of Relative Statistical Weight (LWM) method (1985ZiZY) has been used for discrepant data throughout this evaluation.
Discovery of actinium, thorium, protactinium, and uranium isotopes
2013, Atomic Data and Nuclear Data TablesThirty-one actinium, thirty-one thorium, twenty-eight protactinium, and twenty-three uranium isotopes have so far been observed; the discovery of these isotopes is described. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.
Nuclear data sheets for A = 215, 219, 233, 227, 231
2001, Nuclear Data SheetsThe evaluator presents in this publication spectroscopic data and level schemes from radioactive decay and nuclear reaction studies for all nuclei with mass numbers A=215, 219, 223, 227, and 231. Nuclei with mass number A=215 have spherical shape, and their nuclear structure have been interpreted in terms of the shell model. Nuclei with mass number A=219 belong to a transitional region with spherical, quadrupole, and possibly octupole deformations; those with mass numbers A=223 and 227 belong to a newly studied region of coexisting quadrupole with possible octupole deformations; and nuclei with mass number A=231 essentially have quadrupole deformation. Highlights of this publication are given below: A recent study of the 206Pb(13C,4nγ) reaction (1998St24) has extended up to Jπ=61/2+ the previously known level scheme from 208Pb(13C,6nγ) (1988Fu10,1983Lo16). This study has provided a new interpretation for all the spectroscopic data above the 2247--keV (Jπ=29/2--) level in 215Ra. A new isotope, 219U (42 μs), which was identified with the recoil separator VASSILISSA (1994Ye08,1994AnZY,1993An07), has been included in this evaluation. The first 223Rn β-- decay scheme (1992Ku03) and a significantly improved measurement of 227Ac α decay (1995Sh03) are presented here. A level scheme of 223Fr has been constructed on the basis of these studies, where most of the levels below 600 keV have been assigned to parity doublet bands and interpreted in terms of the reflection--asymmetric rotor model. This evaluation includes the first level structures of 227Fr and 227Th. Levels in 227Fr are from 227Rn β-- decay (1997Ku20); those in 227Th, are from 231U α decay, from 227Pa electron--capture decay, and from 226Ra(α,3nγ) (1997Mu08,1995Li04,1998Ma83). A study of the β-- decay of a mass--separated source of 231Fr has produced the first level scheme of 231Ra (2001Fr05). The only published data (1994Br36,1996Le01) on the electron--capture decay of 231U have provided much information on the level structure of 231Pa. Studies on 232Th(p,2nγ) and Coulomb Excitation of 231Pa (1996Le01,1999Wu05), which have complemented the existing spectroscopic data from these reactions, have suggested the possibility of weak octupole correlations in 231Pa. A new isotope of plutonium, 231Pu (1999La14), has been included in this evaluation.
Nuclear data sheets update for A = 231
1993, Nuclear Data SheetsExperimental data pertaining to nuclear structure of nuclei with mass number A=231 have been complied and evaluated.
Nuclear data sheets for A = 231, 235, 239
1983, Nuclear Data SheetsExperimental data pertaining to nuclear structure of nuclei with mass numbers A=231, 235, and 239 have been compiled and evaluated.
- †
Work performed at Department of Physics, Tohoku University, Sendai, Japan.