Shell model structure at100Sn ? The nuclides98Ag,103In, and104, 105Sn

Schubart, R.; Grawe, H.; Heese, J.; Kluge, H.; Maier, K. H.; Schramm, Michael

doi:10.1007/bf01299755

Cited by 61 publications

(15 citation statements)

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“…The spherical part of the 105 Sn level scheme is in agreement with the previous work [8]. The ground state assignment of I π =5/2 + is based on β + /EC decay [9].…”

Section: Fellowship Supported By Csic Spainsupporting

confidence: 86%

“…The ground state assignment of I π =5/2 + is based on β + /EC decay [9]. All the levels observed up to spin 23/2 + are consistent with excitations of 5 valence neutrons into the d 5/2 , g 7/2 , s 1/2 and d 3/2 orbitals [8]. Positive parity states above the 23/2 + level require either the promotion of two neutrons into the h 11/2 orbit or particle-hole excitations across the Z=50 proton shell gap and are expected, in the absence of deformation, around 7 MeV of excitation energy [10].…”

Section: Fellowship Supported By Csic Spainmentioning

confidence: 73%

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Shears band in the 105Sn nucleus

et al. 1997

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The structure of 105 Sn has been investigated through the 50 Cr( 58 Ni,2pn) reaction at a beam energy of 210 MeV. In addition to an extension of the spherical level scheme, a regular sequence of dipole transitions has been found. The experimental results are in agreement with the prediction of Tilted Axis Cranking calculations, which satisfactorily explain the properties of the band.The recently discovered sequences of ∆I = 1 M1 transitions in the nuclei around 200 Pb [1] [2] show very unusual properties: a high regularity with no signature splitting, the missing or very small crossover E2 transitions indicating small deformation, B(M1) very large (several units of µ 2 N ) and a ratio of the moment of inertia to the B(E2) about an order of magnitude larger than for normal or superdeformed nuclei.The interpretation of this sequences has been given in terms of a novel type of excitation [3,4,5], called 'magnetic' rotation. Different from normal rotation, here it is the magnetic dipole that rotates about the angular momentum vector and not the deformed electrical charge distribution. In the Pb region, the angular momentum increase along the band is generated by the simultaneous reorientation of the spins of the protonparticles (h 9/2 or i 13/2 ) and of the neutron-holes (i 13/2 ). These angular momentum vectors are essentially perpendicular near the bandheads and align with the total angular momentum of the nucleus for increasing rotational frequency ("shears mechanism"). The Tilted Axis Cranking (TAC) model [3] provides the theoretical framework for a description of magnetic rotation and predicts the appearance of similar bands for the A=100 mass region [4] [5]. Here neutron-particles in the h 11/2 orbital and proton-holes in the g 9/2 orbital combine to the rotating dipole. Fellowship supported by CSIC, SpainIn this work we report on the discovery of a shears band in 105 Sn by using in-beam γ-ray spectroscopy.High-spin states of the 105 Sn nucleus were populated using the 58 Ni + 50 Cr reaction at a beam energy of 210 MeV. The target consisted of 2 self-supporting foils of isotopically enriched 50 Cr with a total thickness of 1 mg/cm 2 . The GASP array, with 40 Compton-suppressed Ge detectors and a multiplicity filter of 80 BGO scintillators, was used for a γ-coincidence measurement.In order to select the reaction channel we have used, in addition to the GASP array, the Si-ball ISIS [6] and the recoil mass spectrometer [7].Multipolarity information for the gamma transitions was extracted from directional correlation (DCO) intensity ratios. The proposed level scheme for 105 Sn is shown in Fig. 1.The spherical part of the 105 Sn level scheme is in agreement with the previous work [8]. The ground state assignment of I π =5/2 + is based on β + /EC decay [9]. All the levels observed up to spin 23/2 + are consistent with excitations of 5 valence neutrons into the d 5/2 , g 7/2 , s 1/2 and d 3/2 orbitals [8]. Positive parity states above the 23/2 + level require either the promotion of two neutrons into the h 11/2 orbit ...

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“…The spherical part of the 105 Sn level scheme is in agreement with the previous work [8]. The ground state assignment of I π =5/2 + is based on β + /EC decay [9].…”

Section: Fellowship Supported By Csic Spainsupporting

confidence: 86%

Section: Fellowship Supported By Csic Spainmentioning

confidence: 73%

Shears band in the 105Sn nucleus

et al. 1997

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“…The reason is that 100 Sn is the heaviest N Z nucleus, which may show strong shell closure and is accessible to experimental investigations. A handful of 100 Sn ions have recently been observed in two experiments [1,2], and excited states have been identified in neighboring nuclei, e.g., 97 Ag [3], 98 Ag [4], 100 Cd [5], 102 In [6], and 104 Sn [7]. In this work we report on the observation of excited states in the nucleus 99 48 Cd 51 , which has two proton holes and one neutron outside the 100 Sn core and is now, together with 97 Ag, the closest neighbor to 100 Sn with known excited states.…”

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confidence: 99%

Stability ofS50100n50Deduced from Excited States in
Lipoglavšek¹,
Cederkäll²,
Palacz³
et al. 1996
Phys. Rev. Lett.
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Excited states of neutron deficient nuclei close to 100 Sn were investigated in an in-beam spectroscopic experiment using the NORDBALL detector array. Excited states in 99 Cd were identified for the first time. The measured half-life of an isomeric state in 99 Cd indicates that the stability with respect to quadrupole shape changes is as large in 100 Sn as for other heavy doubly magic nuclei. PACS numbers: 23.20.Lv, 21.10.Tg, 25.70.Gh, 27.60.+j The region of nuclei near 100 Sn has recently come in focus for studies of nuclear structure. The reason is that 100 Sn is the heaviest N Z nucleus, which may show strong shell closure and is accessible to experimental investigations. A handful of 100 Sn ions have recently been observed in two experiments [1,2], and excited states have been identified in neighboring nuclei, e.g., 97 Ag [3], 98 Ag [4], 100 Cd [5], 102 In [6], and 104 Sn [7]. In this work we report on the observation of excited states in the nucleus 99 48 Cd 51 , which has two proton holes and one neutron outside the 100 Sn core and is now, together with 97 Ag, the closest neighbor to 100 Sn with known excited states.An important property of 100 Sn is the degree of rigidity of its spherical equilibrium shape. This is directly related to the excitation energy and transition rates of the lowest 2 1 state. The main wave function component of this state in a microscopic description is an isoscalar mixture of proton and neutron excitations 2d 5͞2 1g 21 9͞2 across the N Z 50 shell closures. This 2 1 1 state will be lowered in energy and its collective strength increased by coupling to the high-lying giant quadrupole vibrations.The excitation energy and collectivity of the 2 1 1 state in 100 Sn are not known from experiment. In the heavy closed-shell nuclei 132 Sn and 208 Pb, the excitation energies of the 2 1 1 states are 4.04 and 4.09 MeV, respectively, while it is 2.70 MeV in the light N Z doubly magic 56 Ni. The splittings of the relevant single particle states 2p 3͞2 1f 7͞2 ( 56 Ni, 6.40 MeV), 2d 5͞2 1g 9͞2 ( 100 Sn, ഠ6 MeV [8]), 2f 7͞2 1h 11͞2 ( 132 Sn, 4.90 MeV), and 2g 9͞2 1i 13͞2 ( 208 Pb, 5.07 MeV) are comparable. Since the lowering by the proton-neutron interaction should be particularly effective when the protons and neutrons occupy identical quantum states, it is not unlikely that, as in 56 Ni, the 2 1 1 state comes lower in 100 Sn than in 132 Sn or 208 Pb. A B͑E2, 2 1 ! 0 1 ͒ 9͑2͒ W.u. was recently measured in 56 Ni [9]. As a consequence, the polarization charges for low energy E2 transitions in the neighborhood of 100 Sn could be enhanced. There is experimental evidence [8] from B͑E2, 6 1 1 ! 4 1 1 ͒ values in light Sn isotopes down to 104 Sn which points to a neutron effective charge of more than 2e, i.e., about twice as large as the values in the 132 Sn and 208 Pb regions. However, the analysis of the Sn transition rates is troubled by the difficulty to fix the amount of configuration mixing in the initial and final states. We will show below that the present experiment provides independent and...

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“…Fig. 4 shows the comparison between the predictions of the statistical model code PACE2 [17] with the experimental values [29] for the production cross sections of 18 ERs in the fusion reaction 58 Ni (250 MeV) + 50 Cr (2 mg/cm 2 ). One can observe an overall quite good agreement between experimental and theoretical values, even if, according to the discussion carried out in Section 2.1, this is not the most favorable case to test the validity of our calculations.…”

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confidence: 99%

“…Comparison between experimental values[29] and PACE2 predictions for the production cross sections of 18 ERs originating from the reaction 58 Ni (250 MeV) + 50 Cr (2 mg/cm 2 ). Calculated points are connected with straight lines to guide the eye.…”

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MOCADI_FUSION: Extension of the Monte-Carlo code MOCADI to heavy-ion fusion–evaporation reactions

Mazzocco¹,

Ackermann²,

Block³

et al. 2008

Nuclear Instruments and Methods in Physics Research Section B:

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Shell model structure at100Sn ? The nuclides98Ag,103In, and104, 105Sn

Cited by 61 publications

References 54 publications

Shears band in the 105Sn nucleus

Shears band in the 105Sn nucleus

Stability ofS50100n50Deduced from Excited States in
Lipoglavšek¹,
Cederkäll²,
Palacz³
et al. 1996
Phys. Rev. Lett.
Self Cite

MOCADI_FUSION: Extension of the Monte-Carlo code MOCADI to heavy-ion fusion–evaporation reactions

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Shell model structure at100Sn ? The nuclides98Ag,103In, and104, 105Sn

Cited by 61 publications

References 54 publications

Shears band in the 105Sn nucleus

Shears band in the 105Sn nucleus

Stability ofS50100n50Deduced from Excited States inLipoglavšek1, Cederkäll2, Palacz3 et al. 1996Phys. Rev. Lett.Self Cite

MOCADI_FUSION: Extension of the Monte-Carlo code MOCADI to heavy-ion fusion–evaporation reactions

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Product

Resources

About

Stability ofS50100n50Deduced from Excited States in
Lipoglavšek¹,
Cederkäll²,
Palacz³
et al. 1996
Phys. Rev. Lett.
Self Cite