Reply [to “Comment on ‘Hillside Seepage: An Analytical Solution to a Nonlinear Dupuit‐Forchheimer Problem’ by S. R. Yates et al.”]

Yates, Scott R.; Warrick, A. W.; Lomen, D. O.

doi:10.1029/wr022i006p00991

Cited by 4 publications

(16 citation statements)

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“…We have generally confirmed the results of the previous study [15] and, in only a few cases, have they been modified. In addition, we have placed 44 new levels and γ rays deexciting 26 levels seen in in-beam fusion evaporation reactions for the first time [17].…”

supporting

confidence: 80%

“…+ levels at 3457 and 3485 keV characterized by Yates et al [15] were also observed in the current work, and important new information for both states has emerged. The new data firmly place a Doppler-broadened 1877-keV γ ray as the transition from the 3457-keV state to the 3 − level and exclude the previous 6 + assignment for that state.…”

supporting

confidence: 62%

“…The angular distribution data were generally sufficient to obtain the sign of a 2 , which, combined with the polarization information, permitted the determination of multipolarities of most transitions. Overall, the detection sensitivity of this measurement was about 10 times better than the previous measurements [15].…”

mentioning

confidence: 59%

“…About 20 years ago, an extensive search conducted in the region of the expected two-phonon excitations with the 144 Sm(α,2n) reaction [15] resulted in a significant extension of the knowledge of the 146 Gd level structure. Among the observed states were 6 + states at 3457 and 3485 keV, which were characterized by E1 decay to the 5 − yrast state.…”

mentioning

confidence: 99%

“…In view of these advances and the availability of α-particle beams, the facilities at the University of Cologne were appropriate for reinvestigating the excited states in 146 Gd with the 144 Sm(α,2n) reaction. A beam energy of 26.3 MeV had been demonstrated to produce the optimal population of nonyrast states, and higher α-particle energies yield only additional yrast population [15]. The 144 Sm target (3.0 mg/cm 2 , enriched to 97.6%, on a thick gold backing) was surrounded by a compact array of nine individual Ge detectors at an average distance of 10 cm and angles of 90…”

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confidence: 99%

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Two-phonon octupole excitation inGd146

et al. 2010

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Based on experimental evidence from the 144 Sm(α,2n) reaction, the 3484.7-keV 6 + state in 146 Gd is identified as the highest-spin member of the 3 − ⊗ 3 − two-phonon octupole quartet. In the harmonic approximation for noninteracting phonons, a degenerate two-phonon multiplet should occur at twice the energy of the one-phonon state. For low-energy quadrupole (λ = 2) shape vibrations, multiphonon states have been characterized in many even-even nuclei; however, these structures frequently exhibit large anharmonicities, even in nearly spherical nuclei [1]. The octupole (λ = 3) mode in doubly magic nuclei likely comes much closer to the ideal harmonic oscillator as a result of the smaller vibrational amplitudes and the larger number of particles participating in the motion. Indeed, a two-phonon 3 − ⊗ 3 − quartet (J π = 0 + , 2 + , 4 + , and 6 + ) should occur at twice the energy of the octupole phonon and is expected to decay with B(E3) values which are twice that of the 3 − → 0 + transition [1,2]. Unfortunately, two-phonon excitations of the octupole type have proven difficult to identify.It is not surprising that 208 Pb, with its 3 − first-excited state at 2614 keV and B(E3; 3 − → 0 + ) of 34 W.u.[3], has been the subject of many searches for the two-phonon octupole quartet at about 5.2 MeV, that is, at 2hω 3 [4]. Firm evidence, an observed cascade of two E3 transitions from a 0 + state at 5241 keV, for the lowest-spin member of the two-phonon quartet in 208 Pb has been obtained [5]. In addition, candidates for the 2 + and 4 + members of the quartet at nearly harmonic energies have been proposed, but these identifications are based primarily on energy arguments and E1 transition rates; the signature cascade of E3 transitions was not observed [6]. Transfer reaction and inelastic light-ion scattering studies [7] support these assignments, but no clear candidate for the 6

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supporting

confidence: 80%

supporting

confidence: 62%

mentioning

confidence: 59%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Two-phonon octupole excitation inGd146

et al. 2010

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Two-proton multiplets in theN=82 nucleus 62 144 Sm82 from in-beamγ-measurements

Rico

Rubio

Taín

et al. 1993

Z. Physik A - Hadrons and Nuclei

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Abstract:In a high sensitivity (a,2n~,) in-beam study of 144Sms2, with the K6lner Wiixfel OSIRIS "f-detector array including a Compton polaximeter, we have identified the complete two-proton multiplets ~rd~-72, lrd-15/~g~/2,-1 ~rg~-/~, lrhll/2d~-/~ and the 9-to 4-members of the 7rhll./~ g7/2 multiplet.PAC." 21.30+y; 21.60.Cs; 27.60.+j Nuclear two-body residual interactions are basic input information for shell model analyses. They are determined in experiment from the excitation energies of the respective two-nucleon levels that in general however lie above the yrast line and are difficult to excite in compound-evaporation reactions. The N=82 144Sm nucleus, with two protons less than the 146Gd shell model core, can however be reached through the (a,2n) reaction. At low beam energy, this reaction transfers little angular momentum to the compound nucleus, and therefore can populate levels well above the yrast line, including the sought-after two proton multiplets.Our (a,2n7) measurements included v-ray excitation functions, which gave 24.5 MeV as a favorable beam energy, singles v-ray angular distributions, and 7"r-coincidences with the W/irfel detector array equipped with five Compton-suppressed Ge-deteetors and a high-sensitivity Compton polarimeter consisting of 5 coaxial Ge-deteetors. The 6 • 107 double coincidence events gave the v-detection sensitivity of 5• -4 of the (a,2n) channel at 1.5 MeV v-ray energy, and accordingly ~44Sm levels fed with >2 ~ could firmly be identified in the data. The highest observed state is the known 5.361 MeV 13-level [1]; below it we identified 86 excited 144Sm states where 72 had not been observed in previous compoundevaporation in-beam v-measurements [1,2].In Fig.1 we show the 144Sm energy levels observed in the present (a,2n) experiments up to 3.7 MeV excitation, which is the region where five low-lying twoproton multiplets should occur. These include the three positive-parity two-hole multiplets involving the rrda/2 and a'gv/2 orbitals, and also the odd-parity multiplets where one proton is lifted into the h11/2 shell. The spin-parity assignments are firm for most of the levels (cf. Fig. 1) and derive largely from the present data, but pertinent literature [3 to 6] has also been considered.The configuration assignments for the above five multiplets are quite clear and based on their expected excitation energies and on the observed Vdecay branchings; more detailed arguments will be presented later [7]. Here we will only comment on some of the states observed in the region of interest which belong to other configurations. The 2.423MeV firm 2 + state must prominently be rSl/2ds-/2 and corresponds [8] to the 146Gd first excited 2 + state at 1.972 MeV. The assignment for the 2.883 MeV 4 + level is ~rd3/2ds/2. These two states are lowered through the attractive ~ = v = 0 particle-hole interaction in the aligned coupling, and they are the only even-parity proton particle-hole states that should occur so low in energy.The two levels slightly above 3.3 MeV are assigned from resonant ...

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Two-Phonon Octupole Excitation in 146Gd

Caballero

Kleinheinz

Rubio

et al. 2006

AIP Conference Proceedings

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Based on experimental evidence from the 144 Sm(α,2n) reaction, the 3484.7-keV 6 + state in 146 Gd is identified as the highest-spin member of the 3 − ⊗ 3 − two-phonon octupole quartet. A previously unknown γ line of 1905.8 keV and E3 character feeding the 3 − octupole state has been observed. These results represent the first observation of a 6 + → 3 − → 0 + cascade of two E3 transitions in an even-even nucleus and provide strong support for the interpretation of the 6 + state as a two-phonon octupole excitation.

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Reply [to “Comment on ‘Hillside Seepage: An Analytical Solution to a Nonlinear Dupuit‐Forchheimer Problem’ by S. R. Yates et al.”]

Cited by 4 publications

References 3 publications

Two-phonon octupole excitation inGd146

Two-phonon octupole excitation inGd146

Two-proton multiplets in theN=82 nucleus 62 144 Sm82 from in-beamγ-measurements

Two-Phonon Octupole Excitation in 146Gd

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