摘要:

A series of experiments were performed to establish excited states in proton emitters151Lu,109I and113Cs. These experiments used (HI, p2n) reactions to populate the proton emitters and employed the recoil decay tagging technique to identify gamma rays in the corresponding proton‐unbound nucleus. Gamma‐decay sequences were established in these nuclei and their configurations were tentatively assigned based on systematic trends. This paper reviews the three experimental studies and discusses the data in comparison with those of their neighboring nuclei. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1615171

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The massA= 140 products of the54Fe (315 MeV) +92Mo reaction were selected by a recoil mass spectrometer and studied in a recoil ‐ delayed &ggr;‐&ggr; coincidence experiment. A new 7 &mgr;s isomer was identified in the drip line nucleus140Dy. Five cascading &ggr; transitions were assigned to the decay of theI&pgr;= 8−{v9/2−[514] ⊗v7/2+[404]}Kisomer via the ground state band transitions. The established structure of140Dy is discussed with reference to the fine structure in proton decay of141Ho. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1615172

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Excited structures in the proton‐rich nucleus140Dy were established following the decay of a 7.3±1.5 &mgr;s,K&pgr;= 8−isomer. The isomer decays into the yrast line at the 8+state, revealing a rotational band with a deduced deformation of &bgr;2= 0.24(3). The isotope140Dy is the daughter of the deformed proton emitter141Ho. The new information obtained here supports the role of deformation in proton emission and the previous assignments of single‐particle configurations to the two proton emitting states in141Ho. In addition, the reduced hindrance factor measured for the isomer is consistent with the trend observed in theN= 74 isotones and shows no deviation which could be attributed to the proximity of140Dy to the proton drip line. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1615173

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We report here on the recent &bgr;‐decay studies made at ISOLDE/CERN to determine the multiparticle breakup mechanism of excited states in light nuclei. The &bgr;‐2p emission in31Ar is resolved. Mirror beta transitions in the A=9 chain are compared and a large asymmetry factor is deduced for the transitions to high excitation energy in9Be (11.8 MeV) and9B (12.2 MeV) fed in the &bgr;‐decay of9Li and9C respectively. It is shown that the asymmetry is not due to experimental problems or differences in the mechanisms of breakup or in the spin of the states, only differences in the partial decay branches of the breakup channels has been found. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1615174

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Symmetry tests between (p,n) type charge‐exchange reactions and beta decay are discussed. An example of such comparison in A=58 system is given with special emphasis to test reliability of charge‐ exchange data as a probe for Gamow‐Teller strength. Data collected so far is reviewed and the recent beta decay experiment at ISOLDE‐CERN is outlined. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1615175

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We have observed the high‐spin states in93Rh populated by delayed‐proton emission following the &bgr; decay of94Ag. The existence of a second isomer in94Ag with I⩾17, T1/2=0.42(5) s, whose &bgr;‐decay energy is at least 15.5 MeV, has been established. This state features most likely the highest spin ever observed for &bgr;‐decaying nuclei. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1615176

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The second excited state (J&pgr;= 1/2+,l= 0) of the proton‐rich nucleus19Na has been observed for the first time using the elastic scattering reaction18Ne+p in inverse kinematics. An intense (4 × 106pps)18Ne radioactive beam was produced at the Radioactive Beam Facility at Louvain‐la‐Neuve to bombard a polyethylene target. The recoil protons were detected at 20 different angles in the LEDA segmented silicon detector. The resulting elastic scattering cross sections have been analysed using theR‐matrix method. We find that the second excited state in19Na lies at the center‐of‐mass energyEc.m.= 1.066 ± 0.003 MeV with respect to the18Ne+p threshold, and has a proton width &Ggr;p= 101 ± 3 keV. The Coulomb shift between the 1/2+mirror levels in19O and19Na is 0.73 MeV, among the largest values currently observed in light exotic nuclei. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1615177

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Recently, the world’s first radioactive20Na beams have been accelerated at the TRIUMF facility. Using the TRIUMF‐UK Detector Array facility we have performed elastic scattering of this beam from protons in a CH2target with the aim of determining resonance parameters of states in21Mg. The region of excitation probed in21Mg has astrophysical importance because resonant contributions to the20Na(p,&ggr;)21Mg reaction rate are thought to be part of the breakout path from the hot CNO cycle to the rp‐process in x‐ray bursters and perhaps novae. The data taken also serve a wider purpose in that comparisons may be made to isobaric analogue states in the mirror21F nucleus, and thus a study of Coulomb energy shifts may be undertaken. An overview of the motivation, of the experiment, and a preliminary analysis of the data taken, is presented. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1615178

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Neutron‐deficient nuclei withTzequals to −3/2 and −2 have been produced at the GANIL/LISE3 facility in fragmentation reactions of a 95MeV/u36Arprimary beam in a12Ctarget. For the first time, &bgr;‐delayed proton and &bgr;‐&ggr; emission has been simultaneously observed in the decay of21Mg,25Siand26P. The decay scheme of the latter is proposed and the Gamow‐Teller strength distribution in its &bgr; decay is compared to shell‐model calculations based on the USD interaction. The B(GT) values derived from the absolute measurement of the &bgr;‐branching ratios are in agreement with the quenching factor of about 60&percent; obtained for allowed Gamow‐Teller transitions in this mass region. A precise half‐life of 43.7 (6)mswas determined for26P, the &bgr;‐2pemission of which was studied. The expected contribution of spectroscopic studies of neutron‐rich nuclei is discussed with respect to the mirror asymmetry phenomenon occuring in analogous &bgr; decays. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1615179

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The excitation function for the elastic scattering p(18Ne,p)18Ne was measured. This study has been undertaken with the first radioactive beam from the SPIRAL facility at GANIL. A thick solid hydrogen cryogenic target was developed for this experiment. Several resonances have been observed, corresponding to excited states in the compound nucleus19Na. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1615180

出版商:AIP    

年代:1903

数据来源: AIP