| 1. |
- JOHNSON, A, et al.
(författare)
-
HIGH-SPIN STUDIES NEAR SN-100 WITH NORDBALL - NEW RESULTS ON IN-102, IN-104 AND SB-108
- 1993
-
Konferensbidrag (refereegranskat)abstract
- The NORDBALL detector array has been used in a gamma-ray spectroscopic study of neutron deficient nuclei close to 100Sn. A beam of 270 MeV 58Ni ions was used to bombard a target of Fe-54. Reaction channel separation was achieved with a 4pi charged particle Si-ball together with a 1pi neutron detector wall. Altogether 29 final nuclei were identified and excited states were observed for the first time in 8 of them. The weakest identified channel was 100Cd which represented 4.10(-3) % of the observed total yield. Level schemes Of 102In, 104In and 108Sb constructed from gamma-gamma-particle-coincidence and gamma-gamma-angular correlation analyses are presented. The observed structures are discussed in the framework of the nuclear shell-model. In 108Sb also a deformed, strongly coupled, level sequence is observed. This deformed structure is interpreted as built on a pig9/2(-1)xnuh11/2 configuration in agreement with TRS calculations.
|
|
| 2. |
- LIDEN, F, et al.
(författare)
-
ALIGNMENT PROCESSES IN CS-119, CS-121 AND CS-123
- 1992
-
Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 550:2, s. 365-390
-
Tidskriftsartikel (refereegranskat)abstract
- Rotational band structures have been observed in the odd-A Cs isotopes 119Cs, 121Cs and 123Cs. The previously known bands have been extended to higher spin values and several new bands have been established. Alignments of both h11/2 protons and neutrons are seen. Of special interest are the alignment frequencies in the (tentative) [422]3/2+ and [404]9/2+ bands which indicate a configuration-dependent proton pairing. Furthermore, the variation of the interaction strength at the first band crossing in the h11/2 bands does not follow the standard cranked-shell-model predictions. This feature is in line with previous systematic observations of alignment processes in high-j intruder bands, and might infer an additional band mixing due to a neutron-proton interaction.(~)[GRAPHICS]
|
|
| 3. |
- SEWERYNIAK, D, et al.
(författare)
-
IN-BEAM SPECTROSCOPY AT THE PROTON-DRIP LINE - FIRST OBSERVATION OF EXCITED-STATES IN SB-106 AND SB-107
- 1994
-
Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 321:4, s. 323-328
-
Tidskriftsartikel (refereegranskat)abstract
- Neutron deficient nuclei close to Sn-100 have been investigated in-beam using the NORDBALL detector array. A target of Fe-54 was bombarded with a beam of Ni-58 at 270 MeV. Evaporation residues were identified by detecting protons and alpha particles in a 4 pi charged particle multi-detector set-up and neutrons in a 1 pi neutron detector wall in coincidence with gamma rays. Excited states of the proton drip line nucleus Sb-106 and of Sb-107 were identified for the first time. The yrast level schemes constructed from gamma-gamma-particle coincidence and gamma-gamma angular correlation analysis are presented and discussed within the framework of the nuclear shell model.
|
|
| 4. |
|
|
| 5. |
- SEWERYNIAK, D, et al.
(författare)
-
IN-BEAM GAMMA-RAY SPECTROSCOPY OF IN-102
- 1993
-
Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 345:2, s. 243-244
-
Tidskriftsartikel (refereegranskat)abstract
- Neutron deficient nuclei close to 100Sn have been investigated in-beam by gamma-ray spectroscopic methods using the NORDBALL detector array. A beam of 270 MeV Ni-58 was used to bombard a target of Fe-54. Reaction channel separation was achieved with a 4pi charged particle multi-detector set-up together with a 1pi neutron detector wall placed in the forward direction. Excited states of 102In were identified for the first time. The level scheme constructed from gamma-gamma-particle-coincidence and gamma-gamma-angular correlation analysis is presented. The structure of 102In is discussed and compared to neighboring nuclei in the framework of the nuclear shell-model.
|
|
| 6. |
- Cederwall, Bo, et al.
(författare)
-
HIGH-SPIN STATES IN BA-121 AND DEFORMATION-DEPENDENT ALIGNMENTS
- 1991
-
Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 529:2, s. 410-428
-
Tidskriftsartikel (refereegranskat)abstract
- The high-spin structure of 121Ba has been investigated by in-beam gamma-ray spectroscopic techniques. Rotational bands based on the h11/2, g7/2 and tentatively d5/2 quasineutron configurations have been established. The alignments of h11/2 protons and neutrons are identified at HBAR-omega-c = 0.35-0.40 MeV in the h11/2 and g7/2 bands whereas an alignment occurs at HBAR-omega-c = 0.29 MeV in the (tentatively) d5/2 band. B(M1)/B(E2) ratios were extracted and contributed to the configuration assignments. The results are interpreted within the cranked mean-field approach.
|
|
| 7. |
- Cederwall, Bo, et al.
(författare)
-
HIGH-SPIN STATES OF BA-120
- 1991
-
Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 338:4, s. 461-462
-
Tidskriftsartikel (refereegranskat)abstract
- The very neutron deficient nucleus 120Ba has been investigated in a high-spin gamma-spectroscopic study. The yrast band of 120Ba is extended up to spin 22 h and one tentatively assigned negative-parity side band is observed up to spin 15 h. The experimental results are compared with Total Routhian Surface calculations.
|
|
| 8. |
- Cederwall, Bo, et al.
(författare)
-
NEUTRON AND PROTON H11/2 ALIGNMENT EFFECTS IN LA-121
- 1991
-
Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 338:4, s. 463-464
-
Tidskriftsartikel (refereegranskat)abstract
- In a gamma-spectroscopic study, excited states in the very neutron deficient nucleus 121La have been established for the first time. Rotational bands build on the 9/2+[404] and 1/2-[550] Nilsson orbitals are observed up to a maximum spin of tentatively 51/2 h. The experimental results are compared with Total Routhian Surface calculations.
|
|
| 9. |
- Cederwall, Bo, et al.
(författare)
-
SIGNATURE INVERSION IN CS-120 - EVIDENCE FOR A RESIDUAL PN INTERACTION
- 1992
-
Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 542:3, s. 454-478
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin states have been observed in the odd-odd isotope 120Cs in S-32-induced reactions. The previously known band is extended to higher spin and several new bands are identified. Band-head configurations have been inferred by comparing the band properties with known bands in the odd nuclei 121Cs and 121Ba. A remarkable signature inversion is observed in the pi-h11/2 x nu-h11/2 band. The experimental data are compared with calculations made within the total routhian surface model and the two-particle plus triaxial rotor model. It is concluded that a significant residual pn interaction rather than triaxiality is responsible for the signature inversion phenomenon in the pi-h11/2 x nu-h11/2 band of 120Cs.(~)[GRAPHICS]
|
|
| 10. |
- DOMBRADI, Z, et al.
(författare)
-
IDENTIFICATION AND SPECTROSCOPY OF THE TE-108 NUCLEUS
- 1994
-
Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 350:1, s. 3-4
-
Tidskriftsartikel (refereegranskat)abstract
- Excited states of Te-108 were populated in the Fe-54 + Ni-58 (270 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron detector systems for reaction channel separation. Gamma rays belonging to the neutron deficient nucleus Te-108 were identified for the first time. On the basis of gammagamma-coincidence and angular correlation relations a level scheme was constructed with tentative spin and parity assignments. The structure of the nucleus is discussed in the framework of systematics of heavier Te nuclei.
|
|
| 11. |
- FAHLANDER, C, et al.
(författare)
-
IN-BEAM SPECTROSCOPY OF TE-110
- 1994
-
Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 577:3-4, s. 773-785
-
Tidskriftsartikel (refereegranskat)abstract
- The neutron-deficient nucleus Te-110 has been investigated by in-beam spectroscopic methods using the NORDBALL multi-detector array. Except for the energy of one level observed in alpha-decay, excited states in Te-110 were previously unknown. The level scheme constructed from gamma gamma-coincidence relationships is presented with tentative spin assignments up to I-pi = 21(-). Above spin 8(+) the yrast states have negative parity. They are most likely the members of a band predominantly based on the nu(h(11/2)g(7/2)) two-quasiparticle configuration. A band crossing is observed at I-pi approximate to 17(-). It is suggested to be caused by the alignment of two h(11/2) neutrons. The cranked shell model correctly predicts the spin alignment, but fails to reproduce the observed band crossing frequency, possibly because of octupole effects.
|
|
| 12. |
|
|
| 13. |
- JUUTINEN, S, et al.
(författare)
-
EVIDENCE FOR BAND TERMINATION IN XE-118
- 1991
-
Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 338:3, s. 365-366
-
Tidskriftsartikel (refereegranskat)abstract
- The yrast band of Xe118 has been extended up to tentatively I-pi = 34+ in a heavy-ion in-beam gamma-spectroscopic study using the NORDBALL detector array. A band crossing is observed at the highest spins and interpreted within the Modified Oscillator Model as a transition to a terminating band.
|
|
| 14. |
- JUUTINEN, S, et al.
(författare)
-
SHAPE COEXISTENCE IN I-117
- 1992
-
Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 344:2, s. 223-224
-
Tidskriftsartikel (refereegranskat)abstract
- The 117I nucleus has been investigated in a high-spin gamma-spectroscopic study using the NORDBALL detector array. The observed level structures are interpreted as resulting from coexisting collective prolate and oblate as well as non-collective oblate shapes.
|
|
| 15. |
- KARNY, M, et al.
(författare)
-
EXCITED-STATES OF I-111 AND THE OBSERVATION OF A 21-NS ISOMER
- 1994
-
Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 350:3, s. 179-180
-
Tidskriftsartikel (refereegranskat)abstract
- Proton rich nuclei close to Sn-100 have been investigated an-beam using the NORDBALL detector array. A beam of 270 MeV Ni-58 was used to bombard a Fe-54 target. Reaction channel separation was achieved with a 4 pi charged particle multi-detector set-up together with a 1 pi neutron detector wall placed in the forward direction. Gamma-ray transitions belonging do the I-111 nucleus were identified for the first time. A level scheme constructed from gamma-gamma-perticle-coincidence analysis is proposed. The level structure is discussed within the framework of the shell model and the systematics of the heavier odd iodine nuclei.
|
|
| 16. |
- TORMANEN, S, et al.
(författare)
-
COMPETING PROTON AND NEUTRON ALIGNMENTS IN NEUTRON-DEFICIENT XE-NUCLEI
- 1994
-
Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 572:2, s. 417-458
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin structures of the neutron-deficient Xe-117, Xe-118, Xe-120 isotopes have been studied by in-beam gamma-ray spectroscopic techniques. The final nuclei have been identified by means of charged-particle detectors. Collective rotational bands based on the neutron d5/2, 97/2 and h11/2 configurations have been identified in Xe-117. In the even Xe-118 and Xe-120 nuclei several new side bands were observed and the previously known bands were extended. The present level schemes include two positive-parity bands constructed to high spin in Xe-118, whereas in Xe-120 three such bands were observed. In order to explain these bands, both proton and neutron (h11/2)2 alignments, as well as the shape degree of freedom, have to be invoked. The possible occurrence of a gammaS-band is addressed and a pronounced structural change for more heavy Xe-isotopes is discussed. All negative-parity side bands are interpreted in terms of proton two-quasiparticle excitations. The experimental data are compared with total routhian surface calculations.
|
|
