On the existence and decay of 149Pr
Abstract
The existence of 2.3 min 149Pr has been confirmed by studies of sources produced by 150Nd(γ,p). Gamma rays were observed at 110, 139, 165, 742 and possibly 578 keV. The total disintegration energy is 3.0±0.2 MeV. There is evidence for a beta-ray branch of 149Pr to the ground state of 149Nd with log ft = 5.9±0.3. A decay scheme is proposed.
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Cited by (14)
Nuclear Structure and Decay Data for A=149 Isobars
2022, Nuclear Data SheetsExperimental nuclear structure and decay data are evaluated for all the 17 known nuclides of mass 149 (Xe, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb). Detailed compiled and evaluated spectroscopic information is presented for each reaction and decay dataset, and recommended values are provided for level properties, α, β and γ radiations, and other spectroscopic parameters, based on an evaluation of all the available experimental data for A=149 isobaric nuclides. Although large amounts of nuclear spectroscopic data are available for nuclides of A=149, yet large gaps in knowledge exist, as described below. For the lowest atomic number nuclide 149Xe, only the isotopic identification has been made, with no data for its ground-state half-life. For 149Cs, 149Tm and 149Yb information is available for only the respective ground states. For 149Ba, 149La and 149Er, limited data exist for excited states. Many of the decay schemes of radioactive nuclei of A=149 are considered as incomplete, either due to large energy differences between the highest observed excited states in daughter nuclides and the respective Q-values, or due to the lack of confirmed γ-ray data, as listed below: 149Cs → 149Ba, 149Ba → 149La, 149La → 149Ce, 149Ce → 149Pr, 149Pr → 149Nd, 149Tb(4.17 min) → 149Gd, 149Ho(21.0 s and 56 s) → 149Dy, 149Er(4 s and 9.6 s) → 149Ho, and 149Tm → 149Er. No data exist for the decay of 149Yb to 149Tm. Data for half-lives of the excited states in this mass chain are generally lacking as given below by the number of excited levels of known half-life / approximate number of known levels in a nuclide: 2/17 for 149Ba, 0/18 for 149La, 3/53 for 149Ce, 3/44 for 149Pr, 17/110 for 149Nd, 9/90 for 149Pm, 10/210 for 149Sm, 2/125 for 149Eu, 6/270 for 149Gd, 5/200 for 149Tb, 3/80 for 149Dy, 3/90 for 149Ho, and 3/14 for 149Er. This work supersedes earlier evaluations of A=149 nuclides published by 2004Si16, 1994Si18, 1985Sz01 and 1976Ho17.
Nuclear data sheets for A = 149
2004, Nuclear Data SheetsNuclear spectroscopic information for known nuclides of mass number 149 (Cs,Ba,La,Ce,Pr,Nd,Pm,Sm,Eu, Gd,Tb,Dy,Ho,Er,Tm,Yb) with Z=55 to 70 and N=94 to 79 have been evaluated and presented together with adopted energies and Jπof levels in these nuclei. No excited state data are yet available for 149Cs, 149Ba, 149La, 149Tm and 149Yb. The existence of 149Cs is reported from mass separation of products from U(p,X) reaction and that of 149Yb from proton decays of 150Lu g.s. and 150Lu isomer. There are no half-life data for 149Cs and 149Yb. In 149Gd, 12 excited superdeformed bands have been reported, in addition to the yrast (g.s.) superdeformed band. In 149Tb, five superdeformed bands are known, whereas in 149Dy there is some evidence of superdeformation, but no discrete gamma rays have been found. The half-life of fully-ionized 149Dy isomer at 2661 keV has been reported to be 11 s, as compared to 0.49 s for the neutral atom. This evaluation supersedes previous full evaluations of A=149 by Nucl. Data Sheets 46 (1985) 1 and Nucl. Data Sheets 19 (1976) 337 and a midstream (in update mode) evaluation by Nucl. Data Sheets 73 (1994) 351
Ground-state β -branching intensities of several fission-product isotopes measured using a total absorption γ-ray spectrometer
1996, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated EquipmentThe final set of results of “ground-state” β−-branching intensities obtained in a program of systematic study of those regions of the fission-product nuclides accessible to investigation using the 252Cf-based INEL ISOL facility are presented. A total absorption γ-ray spectrometer, operating in a 4πγ-β coincidence mode, was used to obtain these “ground-state” β−-branching intensities; where here the “ground-state” is defined to include all states below a selected γ-ray discriminator level. Results obtained for 89Rb, 90gRb, 91Rb, 93Rb, 93Sr, 94Sr, 94Y, 95Sr, 95Y, 140Cs, 142La, 143Ba, 143La, 144Ba, 144La, 145Ba, 145La, 146Ce, 146Pr, 147Ce, 147Pr, 148Ce, 148Pr, (2.27 min), 149Pr, 149Nd, 151Pr, 151Nd, 152Pm (4.1 min), 153Nd, 155Nd, 157Pm, 157Sm, 158Sm and 158Eu are presented and compared with existing published data.
Nuclear Data Sheets Update for A = 149
1994, Nuclear Data SheetsNuclear spectroscopic information for known nuclitides of mass number 149 (Cs,Ba,La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb) with Z=55 to 70 and N=94 to 79 have been evaluated and presented together with adopted energies and Jπ of levels in these nuclei. No excited state data are yet available for 149Cs, 149Ba, 149La, 149Ce, 149Tm, and 149Yb. The existence of 149Cs is reported from mass separation of products from U(p,X) reaction and that of 149Yb from proton decay of 150Lu. There are no half-life data for 149Cs and 149Yb. No data are available for 149Xe but this nucleus was included in mass systematics study of 88Ha24. This evaluation represents a revision of earlier Nuclear Data Sheets for A=149 (85Sz01,76Ho17). In 149gd, nine excited superdeformed bands have been reported, in addition to the yrast (g. s.) superdeformed band.
Nuclear data sheets for A = 149
1985, Nuclear Data SheetsThe twelve members of the 149 mass chain for which data exist include the six odd-proton nuclei with Z=57 to 68 and the six odd-neutron nuclei with N=81 to 92. For the nuclei at the ends of the chain (La, Pr, Ho and Er) almost nothing is known. For the eight nuclei nearer stability, a wide range of experiments have been done and the level structures are well defined. The spate of activity using the techniques of β and γ ray spectroscopy, which occurred in the sixties and early seventies, defined the positions of a large number of states while leaving many spin and parity assignments ambiguous. Charged-particle reaction studies carried out in the seventies and early eighties have removed many of these ambiguities and provided new insights concerning the particle configurations and wave functions. The level structures associated with these twelve nuclei do not, in general, lend themselves to interpretation on simple shell or collective models and a number of solid papers have been published in which the authors attempt to describe these nuclei with more sophisticated models. The evaluators have made no attempt to cover these calculations.
Nuclear data sheets for A = 149
1976, Nuclear Data SheetsThe present work constitutes an updating of the previous A = 149 compilation which appeared in Nuclear Data Sheets in December 1962. The experimental results of over 130 papers up to August 1974 have been included in this compilation.
Data are presented for nine nuclei (Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy). The bulk of the experimental information comes from decay studies, although one- and two-nucleon transfer reaction data from experiments performed since the 1962 compilation have made a major contribution to the determination of spins and parities. The Nd levels are almost entirely determined by (d,t) and (3He,α) data, pointing up the need for further study of the β−-decay leading to this nucleus. The A = 149 nuclei are in a transition region from spherical to deformed nuclei. The systematics of spins and parities in this region will be useful in testing models of intermediate coupling.
Absolute β−-, γ+(ce)-, and ε(+β+)-branching ratios are given on the decay scheme drawings. These quantities are based on a (γ+ce) intensity balance normalized to 100% decay to the ground state of the daughter nucleus. Details of methods used for specific nuclides are discussed for the individual cases.
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Work was performed in the Ames Laboratory of the USAEC, Contribution No. 2057.
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Present address: Natuurkundig Laboratorium (F.O.M.), Rijksuniversiteit, Groningen, Netherlands.