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  • Articles: DFG German National Licenses  (9)
  • 1975-1979  (9)
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  • Articles: DFG German National Licenses  (9)
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Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    On the yrast levels in204Pb (1978)
    Springer
    The European physical journal 284 (1978), S. 217-231 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High-spin states in204Pb were populated in the204Hg(α,4n) reaction using α-particles in the energy region 42–51 MeV. Prompt and delayedγ-rays as well as conversion electrons were studied in addition to excitation functions, angular distributions andγ-γ coincidences. In this way a stretched cascade ofγ-rays from a level at 8125.9 keV was found to feed the previously known isomeric 9− level at 2185.7 keV. Spins and parities were established for levels up to and including a 19− level at 6098.0 keV. The levels with c= 172212; and 19− at excitation energies of 5664.3 and 6098.0 keV are likely to be due to the simplep 1 2/s-1 i 13 2/−3 andf 5 2/−1 i 13 2/−3 configurations. The agreement between calculated and experimental energies for all observed levels in the regionJ=9–19 is very good in cases where the empirical two-particle interactions used are satisfactorily well known. Above the 19− level there are three weakly populated levels at 7402.1, 7849.2 and 8125.9 keV, which are likely to haveJ≥20. None of these energies agrees with the calculated value 7695±20 keV for the 20+ state of thei 13 2/−4 configuration which has the highest angular momentum produced by the four valence neutron holes. This apparent anomaly can be understood if the yrast levels withJ≥20 have angular momentum contribution from the core. It seems likely that the states at 7402.1, 7849.2 and 8125.9 keV are due to proton core excited states of the typeπh 9/2 h 11 2/−1 ×νp 1 2/−2 i 13 2/−2 withJ π=20+ andJ π=21+ andπh 9/2 h 11 2/−1 ×νp 1 2/−1 f 5 2−1 i 13 2/−2 withJ π=22+ or 23+, respectively. The state at 8126 keV has the highest energy so far directly observed in a stretched cascade ofγ-rays from the decay of a heavy nucleus produced in (α, xn) reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01411332
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Particle hole yrast states in146Gd and147Gd and the Z=64 shell closure (1979)
    Springer
    The European physical journal 290 (1979), S. 279-295 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The level structures of146Gd and147Gd have been investigated by in-beamγ-ray ande − spectroscopy with (α, xn) reactions on enriched Sm targets. Detailed level schemes up to ∼4 MeV, which differ radically from earlier schemes, are reported. The energy levels are characterized as particle-hole excitations using empirical single particle energies and two nucleon interactions. Analysis of pure 1p 1h proton excitations demonstrates that theZ=64 andN=82 energy gaps are about equally large.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01408545
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Particle plus octupoleM2/E3 isomers and high-spin particle-hole states in147Tb and148Tb (1979)
    Springer
    The European physical journal 293 (1979), S. 135-149 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The level structures of theN=82 andN=83 nuclei147Tb and148Tb have been studied by means of (α, 8n) and (α,7n) reactions induced by 68 to 110 MeVα particle bombardments of151Eu targets. In-beam conversion electron measurements have established that isomers withT 1/2=4.8(6)ns in147Tb andT 1/2=22(1)ns in148Tb decay byM2+E3 transitions to the ground states. The measuredB(E3) values show that the isomeric states arise from the coupling of the valence nucleon(s) to the146Gd core octupole. Particlephonon coupling in these nuclei and in the one-neutron nucleus147Gd is discussed and compared with well known cases involving the208Pb core. The higher lying yrast states in the two Tb nuclei are described as shell-model particle-hole excitations using empirical single particle energies and nucleon-nucleon interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01559755
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Evidence for a 10+ state in132Te (1979)
    Springer
    The European physical journal 292 (1979), S. 145-151 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new isomeric state witht 1/2=3.9±0.3μs has been observed in the nucleus 52 132 Te80 which has two protons more and two neutrons less than the doubly magic isobar 50 132 Sn82. The deexcitation pattern suggests spin and parity 10+ for this level near 2,700 keV which is populated in fission. The energy and the half-life of the isomer can be understood with the assumption that it is the 10+ level based on theh 11 2/−2 neutron hole configuration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01441621
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    An isomeric 19+ state of the $$\pi h_{{9 \mathord{\left/ {\vphantom {9 2}} \right. \kern-\nulldelimiterspace} 2}}^2 i_{1{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} vg_{{9 \mathord{\left/ {\vphantom {9 2}} \right. \kern-\nulldelimiterspace} 2}} (j^{ - 2} )_{0^ + }$$ configuration in 85 210 At125 and the question of isospin dependence in the two-particle core polarization (1978)
    Springer
    The European physical journal 284 (1978), S. 357-369 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Usingα-particles of energies 35–51 MeV and in-beam conversion electron andγ-spectroscopy techniques, a 4.0±1.7 μs core-excited 19+ isomeric state in210At with ag-factor of 0.737±0.025 has been observed at an excitation energy of 4027.7 keV. The 19+ state is suggested to have the $$\pi h_{{9 \mathord{\left/ {\vphantom {9 2}} \right. \kern-\nulldelimiterspace} 2}}^2 i_{1{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} vg_{{9 \mathord{\left/ {\vphantom {9 2}} \right. \kern-\nulldelimiterspace} 2}} (j^{ - 2} )_{0^ + }$$ configuration with maximum alignment of the angular momenta. The total two-particle core polarization due to theh 9/2 andi 13/2 protons and theg 9/2 neutron was found to be −68±20 keV as compared to −125±18 keV for the 29/2+ isomeric state of the $$\pi h_{{9 \mathord{\left/ {\vphantom {9 2}} \right. \kern-\nulldelimiterspace} 2}}^2 i_{1{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} v(j^{ - 2} )_{0^ + }$$ configuration in209At, which only differs by ag 9/2 neutron. This observation indicates an isospin effect in the two-particle core polarization, which is also supported by recent discoveries of core-excited high-spin levels in208Bi using (d, α)-reactions. Thus in the orbits concerned, a proton-proton pair seems to have a much larger quadrupole polarization effect than a neutron-proton pair.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01422102
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    On the yrast two proton-two neutron hole states in208Po (1978)
    Springer
    The European physical journal 287 (1978), S. 219-228 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High-spin levels in208Po, populated in the208Pb(α,4n)-reaction, were studied usingα-particles in the energy region 41–51 MeV. The energies of levels above the 6+ level have an uncertainty of about 10 keV due to the fact that the 8+→6+ transition has not been observed so far, but this transition has previously been established to be converted neither in theK-shell nor in theL-shells. It was found that the yrast cascade ofγ-rays from a 19+ level at 5896+ε keV feeds levels of lower spin which all can be explained as originating from two proton-two neutron hole configurations. In the higher part of the cascade it is mainly the neutron holes which change their configuration, while the lower part of the cascade is dominated by changes in the proton configuration. The yrast levels in the angular momentum regionJ=8–19 vary practically linearly with energy in the region 1.5–6 MeV. No isomeric traps were found above the 11− level at 2699+ε keV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01408091
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    High spin isomers in151Dy+ (1979)
    Springer
    The European physical journal 290 (1979), S. 337-338 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Three yrast isomers in151Dy, at 6.03 MeV (I=49/2, T/=15(3) ns), 4.90 MeV (41/2−, 5.5(1.0) ns), and at 2.96 MeV(27/2−, 1.3(6) ns) have been located through152Gd(α,5n) and136Ce(18O, 3n) measurements. Shell model configurations are suggested for them.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01408552
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    Evidence for a 3.6 minute isomeric 12− state of the πh 11 2/−1 vi 13 2/−1 configuration in206Tl and effective two-particle interactions (1976)
    Springer
    The European physical journal 278 (1976), S. 257-264 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Using the204Hg(α, pn)-reaction andα-particles of energies 39–55 MeV, we have found an isomeric 3.6 min 12− state in206Tl at 2,642.9 keV which has the two-hole configurationπh 11 2/−1 vi 13 2/−1 The 12− state decays mainly by anE5 transition of energy 1,021.4 keV to a 7+ state at 1,621.5 keV whose main configuration isπs 1 2/−1 vi 13 2/−1 There is, in addition, evidence for a weak 565 keVM 4 branch to an 8+ state at 2,078 keV whose main configuration should beπh 11 2/−1 vf 5 2/−1 . The 7+ state decays by a stretched cascade ofγ-rays to states of the following values ofJ π and excitation energy: 5 − + , 1,405.4 keV; 4−, 952.1 keV; 2−, 265.8 keV and 0−, 0 keV. The main configurations of these states areπh 11 2/−1 vp 1 2/−1 ,πd 3 2/−1 vf 5 2/−1 ,πd 3 2/−1 vp 1 2/−1 andπs 1 2/−1 vp 1 2/−1 respectively. From the nuclear masses of208Pb,207Pb,207Tl, and206Tl and the experimental excitation energies it is possible to obtain the proton hole-neutron hole interaction in206Tl. This interaction is compared with the calculations of Kuo and Herling and the discrepancies are discussed. The 12−→8+ M4 transition rate is reduced because of destructive interference between the protonh 11/2→d 3/2 and the neutroni 13/2→f 5/2 contributions. The magnitude of the reduction is accurately reproduced by the wave functions of Kuo and Herling. The 12−→7+ E5 transition rate is about twice as large as the single-holeπh 11 2/−1 πs 1 2/−1 transition rate. This deviation is fully explained by the configuration admixtures in the 7+ state, given by Kuo and Herling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01409176
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  • 9
    Electronic Resource
    Electronic Resource
    High spin states in205Pb and a precision test of the nuclear shell model for three nucleons (1976)
    Springer
    The European physical journal 277 (1976), S. 273-290 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Using the204Hg(α, 3n) reaction withα-particles of about 40 MeV, we have proved by applying nowadays conventionalγ-ray spectroscopy in-beam technique, that there are two isomeric states in205Pb at the excitation energies 5,161.3 and 3,195.5 keV having the half-lives 71±3 and 217±5 ns, respectively. These isomeric states have spins and parities 33/2+ and 25/2− and are mainly due to thei 13 2/−3 andi 13 2/−2 p 1 2/−1 configurations, respectively. This conclusion is supported by the experimentalg-factors of these states being −0.159±0.008 and −0.0676±0.0011, respectively. It is furthermore shown that theE2 effective neutron charge is the same forE2 transitions from the 33/2+ state in205Pb and from the 12+ state in206Pb as required by the assumption that the208Pb core is responsible for the totalE2 strength of the neutron holes, and that these states are due to thei 13 2/−3 andi 13 2/−2 configurations. The calculatedB(E3) values ofE3 transitions from isomeric states in205Pb and206Pb agree reasonably well with the experimental values as expected from the assumption that theE3-strength should come from particle coupling to the octupole states of the208Pb core. The energies of the six most well established excited states in205Pb with angular momenta in the region 19/2–33/2 were calculated using empirical single-particle energies, empirical two-particle interactions and angular momentum algebra. The average deviation between experimental and calculated energies is −3 keV and the root mean square deviation 6 keV as compared to the uncertainty ± 5 keV in the nuclear masses used in the calculation. For the orbits concerned the shell model is thus valid with an extremely high precision. The contribution of effective three-particle interaction in these orbits must consequently be less than about 5 keV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01415603
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    Paper (German National Licenses)
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