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1.	Ertoprak, Aysegul, et al. (författare) Evidence for octupole collectivity in 172Pt 2020 Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 56:2 Tidskriftsartikel (refereegranskat)abstract Excited states in the extremely neutron-deficient nucleus 172Pt were populated via 96Ru(78Kr,2p) and 92Mo(83Kr,3n) reactions. The level scheme has been extended up to an excitation energy of ~ 5 MeV and tentative spin-parity assignments up to Iπ = 18+. Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negative-parity band. The lowest member of this negative-parity structure was firmly assigned spin-parity 3-. In addition, we observed an E3 transition from this 3- state to the ground state, providing direct evidence for octupole collectivity in 172Pt. Large-scale shell model (LSSM) and total Routhian surface (TRS) calculations have been performed, supporting the interpretation of the 3- state as a collective octupole-vibrational state.
2.	Kerkhof, H. J. M., et al. (författare) Recommendations for standardization and phenotype definitions in genetic studies of osteoarthritis: the TREAT-OA consortium 2011 Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584. ; 19:3, s. 254-264 Tidskriftsartikel (refereegranskat)abstract Objective: To address the need for standardization of osteoarthritis (OA) phenotypes by examining the effect of heterogeneity among symptomatic (SOA) and radiographic osteoarthritis (ROA) phenotypes. Methods: Descriptions of OA phenotypes of the 28 studies involved in the TREAT-OA consortium were collected. We investigated whether different OA definitions result in different association results by creating various hip OA definitions in one large population based cohort (the Rotterdam Study I (RSI)) and testing those for association with gender, age and body mass index using one-way ANOVA. For ROA, we standardized the hip-, knee- and hand ROA definitions and calculated prevalence's of ROA before and after standardization in nine cohort studies. This procedure could only be performed in cohort studies and standardization of SOA definitions was not feasible at this moment. Results: In this consortium, all studies with SOA phenotypes (knee, hip and hand) used a different definition and/or assessment of OA status. For knee-, hip- and hand ROA five, four and seven different definitions were used, respectively. Different hip ROA definitions do lead to different association results. For example, we showed in the RSI that hip OA defined as "at least definite joint space narrowing (JSN) and one definite osteophyte" was not associated with gender (P=0.22), but defined as "at least one definite osteophyte" was significantly associated with gender (P=3 x 10(-9)). Therefore, a standardization process was undertaken for ROA definitions. Before standardization a wide range of ROA prevalence's was observed in the nine cohorts studied. After standardization the range in prevalence of knee- and hip ROA was small. Conclusion: Phenotype definitions influence the prevalence of OA and association with clinical variables. ROA phenotypes within the TREAT-OA consortium were standardized to reduce heterogeneity and improve power in future genetics studies. (C) 2010 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
3.	Parr, E., et al. (författare) Single-particle states and parity doublets in odd- Z Ac 221 and Pa 225 from α -decay spectroscopy 2022 Ingår i: Physical Review C. - 2469-9985. ; 105:3 Tidskriftsartikel (refereegranskat)abstract Low-lying states in the odd-Z isotopes Ac13289221 and Pa13491225 have been studied using α-particle and αγ-coincidence spectroscopy in the Pa225→Ac221→Fr217 decay chain. Ground-state spin and parity assignments of Iπ = 5/2- are proposed for both Ac221 and Pa225, with the odd proton occupying the ω = 5/2 orbital of the quadrupole-octupole deformed shell model in both nuclei. In Ac221, excited states in the bands based on the ω = 5/2 and ω = 3/2 orbitals have been identified, including proposed parity-doublet states. The results suggest that reflection-asymmetric deformation of the ground state persists in the odd-A members of the isotope chains down to N = 132 for Ac and N = 134 for Pa, before reaching the transitional region at N = 130.
4.	Procter, M. G., et al. (författare) Anomalous transition strength in the proton-unbound nucleus (109)(53)I56 2011 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 704:3, s. 118-122 Tidskriftsartikel (refereegranskat)abstract A lifetime measurement has been made for the first excited 11/2(+) state in the proton-unbound nucleus (109)(53)I56 using the recoil-distance Doppler-shift method in conjunction with recoil-proton tagging. The experimental reduced transition probability is considerably smaller than the prediction of theoretical shell-model calculations using the CD-Bonn nucleon-nucleon potential. The discrepancy between the theoretical and experimental reduced transition strengths in this work most likely arises from the inability of the current shell-model calculations to accurately account for the behavior of the unbound nuclear states.
5.	Procter, M. G., et al. (författare) Lifetime measurement in the proton-unbound nucleus 109I 2011 Ingår i: AIP Conf. Proc.. - : AIP. - 9780735409835 ; , s. 105-110 Konferensbidrag (refereegranskat)abstract The Recoil-Distance Doppler-shift method has been combined with Recoil-Decay Tagging for the first time to measure a lifetime in the proton-unbound nucleus 109I. The lifetime value was determined using the Differential Decay-Curve method in singles mode. The result has been compared to theoretical shell-model calculations in order to better understand the nature of unbound valence nucleons at the proton drip line.
6.	Zhang, W., et al. (författare) Decay spectroscopy of 171,172Os and 171,172,174Ir 2023 Ingår i: Physical Review C. - : American Physical Society (APS). - 2469-9985 .- 2469-9993. ; 107:1 Tidskriftsartikel (refereegranskat)abstract We report on a study of the α-decay fine structure and the associated Eα−Eγ correlations in the decays of 171,172Os and 171,172,174Ir. In total, 13 new α-decay energy lines have been resolved, and three new γ-ray transitions have been observed following the new decay branches to 168Re and 167W. The weak α-decay branch from the bandhead of the νi13/2 band in 171Os observed in this work highlights an unusual competition between α, β, and electromagnetic decays from this isomeric state. The nucleus 171Os is therefore one of few nuclei observed to exhibit three different decay modes from the same excited state. The nuclei of interest were produced in 92Mo(83Kr,xpyn) fusion-evaporation reactions at the Accelerator Laboratory of the University of Jyväskylä, Finland. The fusion products were selected using the gas-filled ion separator RITU and their decays were characterized using an array of detectors for charged particles and electromagnetic radiation known as GREAT. Prompt γ-ray transitions were detected and correlated with the decays using the JUROGAM II germanium detector array surrounding the target position. Results obtained from total Routhian surface (TRS) calculations suggest that α-decay fine structure and the associated hindrance factors may be a sensitive probe of even relatively small shape changes between the final states in the daughter nucleus.
7.	Bianco, L., et al. (författare) Discovery of W-157 and Os-161 2010 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 690:1, s. 15-18 Tidskriftsartikel (refereegranskat)abstract The nuclides W-157 and Os-161 have been discovered ill reactions of Ni-58 ion beams with a Cd-106 target. The Os-161 alpha-decay energy and half-life were 6890 +/- 12 keV and 640 +/- 60 mu s. The daughter W-157 nuclei beta-decayed with a half-life of 275 +/- 40 ms, populating both low-lying alpha-decaying states in Ta-157, which is consistent with a 7/2(-) ground state in W-157. Fine structure observed in the alpha decay of Os-161 places the lowest excited state in W-157 with 1(pi) = 9/2(-) at 318 +/- 30 key. The branching ratio of 5.5(-2.2)(+3.1)% indicates that Os-161 also has a 7/2(-) ground state. Shell-model calculations analysing the effects of monopole shifts and a tensor force on the relative energies of 2f(7/2) and 1h(9/2) neutron states in N = 83 isotones are presented. (C) 2010 Elsevier B.V. All rights reserved.
8.	Hilton, J., et al. (författare) α -spectroscopy studies of the new nuclides Pt 165 and Hg 170 2019 Ingår i: Physical Review C. - 2469-9985. ; 100:1 Tidskriftsartikel (refereegranskat)abstract The new nuclides Pt165 and Hg170 were produced in the reactions Mo92(Kr78,5n) and Ru96(Kr78,4n) at bombarding energies of 418 MeV and 390 MeV, respectively. For Hg170 an α-particle energy of Eα=7590(30)keV and half-life of t1/2=0.08-0.04+0.40ms were deduced, while for Pt165 the corresponding values were 7272(14) keV and 0.26-0.09+0.26ms. Comparison of the reduced α-decay widths with systematics indicates that both α decays are unhindered. Although combining the measured α-decay Q values with extrapolated masses suggests that both new nuclides are unbound to two-proton emission by more than 1 MeV, their α-decay half-lives are too short for this decay mode to compete. Improved data were also obtained for Pt166,167, produced via the Ru96(Kr78,α4n) and Ru96(Kr78,α3n) reactions at bombarding energies of 390 MeV and 418 MeV.
9.	Joss, D. T., et al. (författare) Evolving collective structures in the transitional nuclei W-162 and W-164 2016 Ingår i: PHYSICAL REVIEW C. - : American Physical Society. - 2469-9985. ; 93:2 Tidskriftsartikel (refereegranskat)abstract Excited states in the neutron-deficient nuclides(74)(162)W(88) and W-164(74)90 were investigated by using the gamma-ray spectrometer Jurogam. A change in structure is apparent from the first rotational alignments in W-162 and W-164, whose rotationally aligned bands are interpreted as nu(h(9/2))(2) and nu(i(13/2))(2) configurations, respectively. The level schemes have been extended using recoil (-decay) correlations with the observation of excited collective structures. Configuration assignments have been made on the basis of comparisons of the deduced aligned angular momentum, as a function of rotational frequency, with the predictions of the cranked shell model.
10.	Joss, D. T., et al. (författare) The influence of quasineutron configurations on 161Ta and nearby odd-A nuclei 2011 Ingår i: AIP Conf. Proc.. - : AIP. - 9780735409835 ; , s. 43-48 Konferensbidrag (refereegranskat)abstract Several strongly coupled bands in the neutron-deficient nucleus 161Ta have been identified and quasiparticle configuration assignments have been made on the basis of rotational alignments and cranked shell model calculations. The level scheme elucidated for 161Ta highlights the competition between the ν(h 9/2) and ν(i 13/2) orbitals to form the yrast spectrum. The band structures in 161Ta also provide new insights into the structural features of other heavy odd-A nuclei populated with much lower reaction cross sections in this region at the proton drip line.
11.	Petts, A., et al. (författare) Lifetime measurements and coulomb excitation of light Hg nuclei 2009 Ingår i: Capture Gamma-Ray Spectroscopy and Related Topics. - : American Institute of Physics (AIP). - 9780735406230 ; , s. 414-418 Konferensbidrag (refereegranskat)abstract Two complementary experimental programs have taken place to investigate the origin and evolution of shape coexistence in the light mercury region. Recoil Distance Doppler-shift measurements were performed at the University of Jyväskylä utilizing the Köln plunger device in conjunction with the JUROGAM + RITU + GREAT setup. In addition, Coulomb excitation measurements of 184,186,188Hg were performed at REX-ISOLDE using the MINIBALL Ge-detector array. The results of the lifetime measurements of the yrast states up to Iπ = 10+ in 182Hg are reported. Preliminary analysis of the Coulomb excitation data is also discussed.
12.	Bäck, Torbjörn, et al. (författare) Lifetime measurement of the first excited 2(+) state in (108)Te 2011 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 84:4, s. 041306- Tidskriftsartikel (refereegranskat)abstract The lifetime of the first excited 2(+) state in the neutron deficient nuclide (108)Te has been measured for the first time, using a combined recoil decay tagging and recoil distance Doppler shift technique. The deduced reduced transition probability is B(E2;0(g.s.)(+) -> 2(+)) = 0.39(-0.04)(+0.05)e(2)b(2). Compared to previous experimental data on neutron deficient tellurium isotopes, the new data point constitutes a large step (six neutrons) toward the N = 50 shell closure. In contrast to what has earlier been reported for the light tin isotopes, our result for tellurium does not show any enhanced transition probability with respect to the theoretical predictions and the tellurium systematics including the new data is successfully reproduced by state-of-the-art shell model calculations.
13.	Cederwall, Bo, et al. (författare) Coexistence in proton rich A-90 and A-170 nuclei. 1998 Ingår i: Abstracts of Papers of the American Chemical Society. - 0065-7727. ; 215, s. U955-U955 Tidskriftsartikel (refereegranskat)
14.	Davis-Merry, T. R., et al. (författare) Collective excitations in the transitional nuclei Re-163 and Re-165 2015 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 91:3 Tidskriftsartikel (refereegranskat)abstract Excited states in the neutron-deficient nuclei (163)(75) Re-88 and (165)(75) Re-90 were populated in the Cd-106(Ni-60, p2n gamma) and Mo-92(Kr-78, 3p2n gamma) fusion-evaporation reactions at bombarding energies of 270 and 380 MeV, respectively.. rays were detected at the target position using the JUROGAM spectrometer while recoiling ions were separated in-flight by the RITU gas-filled recoil separator and implanted in the GREAT spectrometer. The energy level schemes for Re-163 and Re-165 were identified using recoil-decay correlation techniques. At low spin, the yrast bands of these isotopes consist of signature partner bands based on a single pi h(11/2) quasiproton configuration. The bands display large energy splitting consistent with the soft triaxial shape typical of transitional nuclei above N = 82. The configurations of the excited states are proposed within the framework of the cranked shell model.
15.	Drummond, M. C., et al. (författare) Low-lying excited states in the neutron-deficient isotopes Os-163 and Os-165 2013 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 87:5, s. 054309- Tidskriftsartikel (refereegranskat)abstract Excited states in the neutron-deficient isotopes Os-163 and Os-165 were identified using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator. The Os-163 and Os-165 nuclei were populated via the Cd-106(Ni-60,3n) and Mo-92(Kr-78,2p3n) reactions at bombarding energies of 270 MeV and 357 MeV, respectively. Gamma-ray emissions from these nuclei have been established unambiguously using the recoil-decay tagging technique and a coincidence analysis has allowed level schemes to be established. These results suggest that the yrast states are based upon negative-parity configurations originating from the f(7/2) and h(9/2) orbitals.
16.	Gillespie, S. A., et al. (författare) Identification of a 6.6 μ s isomeric state in Ir 175 2019 Ingår i: Physical Review C. - 2469-9985. ; 99:6 Tidskriftsartikel (refereegranskat)abstract An experiment has been performed to study excited states in the neutron-deficient nucleus Ir175 via the use of the JUROGAM II high-purity germanium detector array and the RITU gas-filled separator at JYFL, Jyväskylä. By using isomer tagging, an isomeric state with a half-life of 6.58(15) μs has been observed in Ir175 for the first time. It has been established that the isomer decays via a 45.2 (E1)-26.1 (M1) keV cascade to new states below the previously reported ground state in Ir175 with Iπ=(5/2-). We now reassign this (5/2-) state to the isomeric state discovered in this study.
17.	Gillespie, S. A., et al. (författare) Identification of sub- μ s isomeric states in the odd-odd nucleus Au 178 2021 Ingår i: Physical Review C. - 2469-9985. ; 103:4 Tidskriftsartikel (refereegranskat)abstract The neutron-deficient gold (Z=79) isotopes in the vicinity of the neutron midshell N=104 provide prolific examples of shape coexistence and isomerism at low excitation energy. They can be probed via a number of different experimental techniques. In this study, two new isomeric states with half-lives of 294(7) and 373(9) ns have been observed in the neutron-deficient odd-odd nuclide Au178 (N=99) in an experiment at the RITU gas-filled separator at JYFL, Jyväskylä. This result was achieved due to the use of a segmented planar germanium detector with a high efficiency at low energies. By applying the recoil-decay tagging technique, they were assigned to decay to two different long-lived α-decaying states in Au178.
18.	Lewis, M. C., et al. (författare) Decay of a 19(-) isomeric state in Lu-156 2018 Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 98:2 Tidskriftsartikel (refereegranskat)abstract A multiparticle spin-trap isomeric state having a half-life of 179(4) ns and lying 2601 keV above the yrast 10(+) state in Lu-156 has been discovered. The Lu-156 nuclei were produced by bombarding isotopically enriched Cd-106 targets with beams of Ni-58 ions, separated in flight using the gas-filled separator RITU and their decays were measured using the GREAT spectrometer. Analysis of the main decay path that populates yrast states observed previously suggests a spin-parity assignment of 19(-) for the isomeric state, which is consistent with isomeric states identified in the N = 85 isotones. Comparison with other decay paths in Lu-156 indicates that the [pi h(11/)(2)(-1) circle times nu h(9/2)]10(+) state at the bottom of the yrast sequence is likely to be the a-decaying isomeric state, with the [pi h(11/)(2)(-1) circle times nu f(7/2)]9(+) state lying 62 keV above it. The relative ordering of the lowest-lying 9(+) and 10(+) states is inverted in Lu-156 compared with its odd-odd isotones.
19.	Parr, E., et al. (författare) Identification of the J(pi)=1(-) state in Ra-218 populated via alpha decay of Th-222 2016 Ingår i: PHYSICAL REVIEW C. - 2469-9985. ; 94:1 Tidskriftsartikel (refereegranskat)abstract The alpha decay of Th-222 populating the low-lying J(pi) = 3(-) state, and also a proposed 1(-) state, in Ra-218 has been observed. The observations suggest an excitation energy of 853 keV for the 1(-) state, which is 60 keV above the 3(-) state. The hindrance factors of these alpha decays give a possible boundary to the region of ground-state octupole deformation in the light-actinide nuclei. The relative positions of the J(pi) = 1(-) and 3(-) states suggest they are produced by an octupole-vibrational mechanism, as opposed to alpha clustering or rotations of a reflection-asymmetric octupole-deformed shape.
20.	Wadsworth, R., et al. (författare) THE NORTHWEST FRONTIER : SPECTROSCOPY OF N similar to Z NUCLEI BELOW MASS 100 2009 Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 40:3, s. 611-620 Tidskriftsartikel (refereegranskat)abstract The spectroscopy and structure of excited states of N similar to Z nuclei in the mass 70-100 region has been investigated using two techniques. In the A similar to 70-80 region fusion evaporation reactions coupled with the recoil-beta-tagging method have been employed at Jyvaskyla to study low-lying states in odd-odd N = Z nuclei. Results from these and other data for known odd-odd nuclei above mass 60 will be discussed. In the heavier mass 90 region a fragmentation experiment has been performed using the RIS-ING/FRS setup at GSI. This experiment was primarily aimed at searching for spin gap isomers in nuclei around A similar to 96. The objectives of the latter experiment will be discussed.
21.	Briselet, R., et al. (författare) Production cross section and decay study of Es 243 and Md 249 2019 Ingår i: Physical Review C. - 2469-9985. ; 99:2 Tidskriftsartikel (refereegranskat)abstract In the study of the odd-Z, even-N nuclei Es243 and Md249, performed at the University of Jyväskylä, the fusion-evaporation reactions Au197(Ca48,2n)Es243 and Tl203(Ca48,2n)Md249 have been used for the first time. Fusion-evaporation residues were selected and detected using a gas-filled separator coupled with its focal-plane spectrometer. For Es243, the recoil decay correlation analysis yielded a half-life of 24±3s and a maximum production cross section of 37±10nb. In the same way, a half-life of 26±1s, an α-branching ratio of 75±5%, and a maximum production cross section of 300±80nb were determined for Md249. The decay properties of Es245, the daughter of Md249, were also measured: an α-branching ratio of 54±7% and a half-life of 65±6s. Experimental cross sections were compared to the results of calculations performed using the kewpie2 statistical fusion-evaporation code.
22.	Doncel, Maria, et al. (författare) Lifetime measurement of the first excited 2(+) state in Te-112 2015 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 91:6 Tidskriftsartikel (refereegranskat)abstract The lifetime of the 2(+) --> 0(g.s.)(+) transition in the neutron-deficicient nucleus Te-112 has been measured for the first time using the DPUNS plunger and the recoil distance Doppler shift technique. The deduced value for the reduced transition probability is B(E2 :0(g.s.)(+) --> 2(+)) = 0.46 +/- 0.04 e(2)b(2), indicating that there is no unexpected enhancement of the B(E2 :0(g.s.)(+) --> 2(+)) values in Te isotopes below the midshell. The result is compared to and discussed in the framework of large-scale shell-model calculations.
23.	Hadinia, Baharak, et al. (författare) Identification of gamma rays from Au-172 and alpha decays of Au-172, Ir-168, and Re-164 2009 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 80:6, s. 064310- Tidskriftsartikel (refereegranskat)abstract The very neutron deficient odd-odd nucleus Au-172 was studied in reactions of 342 and 348 MeV Kr-78 beams with an isotopically enriched Ru-96 target. The alpha decays previously reported for Au-172 were confirmed and the decay chain extended down to Tm-152 through the discovery of a new alpha-decaying state in Re-164 [E-alpha=5623(10) keV; t(1/2)=864(-110)(+150) ms; b(alpha)=3(1)%]. Fine structure in these alpha decays of Au-172 and Ir-168 were identified. A new alpha-decaying state was also observed and assigned as the ground state in Au-172 [E-alpha=6762(10) keV; t(1/2)=22(-5)(+6) ms]. This decay chain was also correlated down to Tm-152 through previously reported alpha decays. Prompt gamma rays from excited states in Au-172 have been identified using the recoil-decay tagging technique. The partial level scheme constructed for Au-172 indicates that it has an irregular structure. Possible configurations of the alpha-decaying states in Au-172 are discussed in terms of the systematics of nuclei in this region and total Routhian surface calculations.
24.	Hodge, D., et al. (författare) Identification of a dipole band above the Iπ=31/2- isomeric state in Pb 189 2015 Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 92:5 Tidskriftsartikel (refereegranskat)abstract A dipole band of six transitions built upon a firmly established Iπ=31/2- isomeric state has been identified in Pb189 using recoil-isomer tagging. This is the lightest odd-mass Pb nucleus in which a dipole band is known. The dipole nature of the new transitions has been confirmed through angular-intensity arguments. The evolution of the excitation energy and the aligned-angular momentum of the states in the new dipole band are compared with those of dipole bands in heavier, odd-mass lead isotopes. This comparison suggests that the new band in Pb189 is based upon a π[s1/2-2h9/2i13/2]11- - ν[i13/2+-1]13/2+ configuration. However, the increased aligned-angular momentum in Pb189 may suggest evidence for a reduced repulsive proton/neutron-hole interaction compared to dipole bands in the heavier mass isotopes.
25.	Hornillos, M. B. G., et al. (författare) gamma-ray spectroscopy approaching the limits of existence of atomic nuclei : A study of the excited states of Pt-168 and Pt-169 2009 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 79:6 Tidskriftsartikel (refereegranskat)abstract Excited states in the N=90 and N=91 Pt nuclei have been investigated using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator. These nuclei were populated via the reactions Mo-92(Kr-78,2n) and Mo-94(Kr-78,3n) at 335 and 348 MeV, respectively. The recoil-decay tagging technique has been used to correlate prompt gamma radiation with the characteristic alpha decays of Pt-168 and Pt-169. A gamma-gamma analysis has allowed a level scheme for Pt-168 to be reported for the first time and the level scheme for Pt-169 to be extended. The excitation energies of the proposed positive-parity yrast states of Pt-168 are compared with calculations based on the interacting boson model and found to be in excellent agreement. These data show a continuation of the trend toward vibrational nuclei as the N=82 shell gap is approached. In addition, new excited states constituting two decay paths have been discovered in Pt-169. .
26.	Joss, D. T., et al. (författare) Identification of excited states in Os-167 and Os-168 : shape coexistence at extreme neutron deficiency 2001 Ingår i: Nuclear Physics A. - : Elsevier. - 0375-9474 .- 1873-1554. ; 689:04-mar, s. 631-654 Tidskriftsartikel (refereegranskat)abstract Excited states in the very neutron-deficient isotopes Os-167 and Os-168 have been observed using the reaction Sn-112(Ni-58, 2pxn). The JUROSPHERE gamma -ray spectrometer array was used in conjunction with the RITU gas-filled recoil separator to collect prompt gamma radiation in coincidence with recoils implanted in a silicon strip detector located at the focal plane of RITU. Using a selective recoil decay tagging technique it has been possible to unambiguously assign gamma -ray transitions to Os-167 and Os-168 through the characteristic a radioactivity of these nuclides. The high-spin structure of the bands is discussed in terms of quasiparticle configurations within the framework of the cranked shell model. The role of shape coexistence in Os-168 is examined with phenomenological three-band mixing calculations.
27.	Joss, D. T., et al. (författare) Yrast spectroscopy in the neutron-deficient nucleus Os-169 2002 Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 66:5 Tidskriftsartikel (refereegranskat)abstract Excited states in the neutron-deficient isotope Os-169 have been identified for the first time in an experiment using the Jurosphere gamma-ray spectrometer in conjunction with the Ritu gas-filled recoil separator. The problems associated with identifying neutron-deficient isotopes produced with low fusion cross sections against a high background of competing channels, including fission, have been overcome by using the recoil-decay tagging technique. The band structures observed in Os-169 are interpreted in the context of the systematics of neighboring nuclei and the predictions of cranked Woods-Saxon calculations. The systematics of the second (i(13/2))(2) neutron alignment in this region are discussed.
28.	Ketelhut, S., et al. (författare) gamma-Ray Spectroscopy at the Limits : First Observation of Rotational Bands in Lr-255 2009 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:21, s. 212501- Tidskriftsartikel (refereegranskat)abstract The rotational band structure of Lr-255 has been investigated using advanced in-beam gamma-ray spectroscopic techniques. To date, Lr-255 is the heaviest nucleus to be studied in this manner. One rotational band has been unambiguously observed and strong evidence for a second rotational structure was found. The structures are tentatively assigned to be based on the 1/2(-)[521] and 7/2(-)[514] Nilsson states, consistent with assignments from recently obtained alpha decay data. The experimental rotational band dynamic moment of inertia is used to test self-consistent mean-field calculations using the Skyrme SLy4 interaction and a density-dependent pairing force.
29.	Leguillon, R., et al. (författare) High-spin spectroscopy of Nd-140 2013 Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 88:1 Tidskriftsartikel (refereegranskat)abstract The population of the high-spin states in Nd-140 was investigated using the reaction Zr-96(Ca-48,4n). The results from two experiments, one with the EUROBALL array and one with the JUROGAM II + RITU + GREAT setup employing the recoil decay tagging technique, have been combined to develop a very detailed level scheme for Nd-140. Twelve bands of quadrupole transitions and eleven bands of dipole transitions were identified and their connections to low-lying states were established. Calculations using the cranked Nilsson-Strutinsky and the tilted axis cranking models were used to interpret the observed structures. The overall good agreement between the experimental results and the calculations assuming a triaxial shape of the nucleus strongly support the existence of a stable triaxial shape at high spins in this mass region.
30.	Lv, B. F., et al. (författare) Evolution from γ -soft to stable triaxiality in Nd 136 as a prerequisite of chirality 2018 Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 98:4 Tidskriftsartikel (refereegranskat)abstract The level structure of Nd136 has been investigated using the Mo100(Ar40,4n) reaction and the JUROGAM II+RITU+GREAT setup. The level scheme has been extended significantly. Many new bands have been identified both at low and high spin, among which are five nearly degenerate bands interpreted as chiral partners. Excitation energies, spins, and parities of the previously known bands are revised and firmly established, and some previously known bands have been revised. Configurations are assigned to the observed bands based on cranked Nilsson-Strutinsky calculations. The band structure of Nd136 is now clarified and the various types of single-particle and collective excitations are well understood.
31.	Mach, H., et al. (författare) Application of ultra-fast timing techniques to the study of exotic and weakly produced nuclei 2005 Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1421-S1426 Tidskriftsartikel (refereegranskat)abstract Ultra-fast time-delayed techniques have been recently applied in a number of studies where exotic nuclei were identified using advanced selection techniques. These include large Compton-suppressed Ge arrays, in-flight separators or recoil separators. Some of the new results are discussed in this presentation. Besides the results for Mg-32 and Pd-96, they include the first determination of the half-life of the 8(+) state in Ge-80, T-1/2 = 2.95(6) ns, and significantly more precise results for Mn-51 (3680 keV level) and V-48 (421 keV level), T-1/2 = 1760(40) ps and T-1/2.
32.	Page, R. D., et al. (författare) alpha decay of Re-159 and proton emission from Ta-155 2007 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 75:6, s. 061302- Tidskriftsartikel (refereegranskat)abstract The alpha decay of Re-159 has been observed for the first time in reactions of 300 MeV Ni-58 ions with an isotopically enriched Cd-106 target. The Re-159 ions were separated in-flight using the RITU separator and implanted into the GREAT spectrometer. The alpha decay emanates from the proton-emitting pi h(11/2) state in Re-159 with an energy of E-alpha=6776 +/- 26 keV and a branching ratio of 7.5 +/- 3.5%. This alpha decay populates a state in the closed neutron shell nucleus Ta-155, which decays by emitting 1444 +/- 15 keV protons with a half-life of 2.9(-1.1)(+1.5) ms. These values are consistent with the emission of the proton from a pi h(11/2) orbital. These results fit in with the systematics of proton and alpha-particle separation energies in the region, but disagree with the previously reported decay properties of Ta-155.
33.	Petri, M., et al. (författare) Nuclear levels in proton-unbound I-109 : Relative single-particle energies beyond the proton drip line 2007 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 76:5 Tidskriftsartikel (refereegranskat)abstract A level scheme has been constructed for the proton-unbound, T-z=3/2 nuclide I-109(53)56 following a recoil-decay-tagging experiment using the Ni-58(Fe-54, p2n gamma) reaction at a beam energy of 195 MeV. The experiment was performed using the highly efficient JUROGAM gamma-ray spectrometer in conjunction with the RITU gas-filled recoil separator and the GREAT focal-plane spectrometer. Cranking calculations are used to interpret band structures built on pi g(7/2) and pi h(11/2) states in a weakly deformed, triaxial nucleus.
34.	Procter, M. G., et al. (författare) Isomer-tagged differential-plunger measurements in Xe-113(54) 2013 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 87:1, s. 014308- Tidskriftsartikel (refereegranskat)abstract The 278-keV M2 gamma decay from the vh(11/2) isomeric state in Xe-113 has been observed for the first time using the recoil-isomer tagging technique. The half-life of the isomer has been measured to be 6.9(3) mu s. The derived B(M2) value is in agreement with the trend of systematic measurements of M2 transition strengths in neutron-deficient tellurium and tin isotopes. The lifetime of the first excited state in the vh(11/2) band has been measured using the recoil distance Doppler-shift method. The extracted B(E2) value has been compared to theoretical CD-Bonn calculations and recent lifetime measurements in Te-109. This comparison of B(E2) values has been used to shed light on the possible influence of collective degrees of freedom on M2 transition strengths in the most neutron-deficient xenon nuclei. The vh(11/2) band is deduced to have a degree of deformation comparable with the ground-state bands of the even-mass xenon isotopes. However, the value deduced in this work indicates a loss of collective behavior when compared with the lower-mass Te-109. This result suggests that, while changes in deformation may be partly responsible for the observed trend in B(M2) values for increasing Z, other effects may also be present.
35.	Singh, B. S. Nara, et al. (författare) Coulomb shifts and shape changes in the mass 70 region 2007 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 75:6 Tidskriftsartikel (refereegranskat)abstract The technique of recoil beta tagging has been developed which allows prompt gamma decays in nuclei from excited states to be correlated with electrons from their subsequent short-lived beta decay. This technique is ideal for studying nuclei very far from stability and improves in sensitivity for very short-lived decays and for high decay Q-values. The method has allowed excited states in Y-78 to be observed for the first time, as well as an extension in the knowledge of T=1 states in Rb-74. From this new information it has been possible to compare Coulomb energy differences (CED) between T=1 states in Br-70/Se-70, Rb-74/Kr-74, and Y-78/Sr-78. The A=70 CED exhibit an anomalous behavior which is inconsistent with all other known CED. This behavior may be accounted for qualitatively in terms of small variations in the Coulomb energy arising from shape changes.
36.	Taylor, M. J., et al. (författare) Competing single-particle and collective states in the low-energy structure of I-113 2013 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 88:5, s. 054307- Tidskriftsartikel (refereegranskat)abstract To understand the low-energy structure of the neutron deficient iodine isotopes, lifetimes for the low-lying 9/2(+) and 11/2(+) positive-parity states in I-113 have been measured as tau = 28(4) ps and tau = 3.7(7) ps, respectively. The lifetime for the 11/2(-) state, which feeds the 9/2(+) and 11/2(+) states, was remeasured with improved accuracy as tau = 216(7) ps. The reduced transition probability, B(E2) = 32(5) W.u., for the 9/2(+) -> 5/2(+) transition agrees with that calculated within the shell model using a Hamiltonian based on the charge-dependent Bonn nucleon-nucleon interaction. In contrast, the much larger transition probability, B(E2) = 209(39) W.u., measured for the 11/2(+) -> 7/2(+) transition has been interpreted, with the aid of configuration-constrained total Routhian surface calculations, as resulting from a slightly gamma-soft rotor with an associated quadrupole deformation of beta(2) approximate to 0.18. Remarkably similar reduced E1 transition probabilities of 5.5(5) x 10(-4) and 4.9(5) x 10(-4) W.u. were deduced for the 11/2(-) -> 9/2(+) and 11/2(-) -> 11/2(+) transitions, respectively, which feed apparently dissimilar but competing structures.
37.	Taylor, M. J., et al. (författare) Oblately deformed isomeric proton-emitting state in Lu-151 2015 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 91:4 Tidskriftsartikel (refereegranskat)abstract Gamma rays from excited states feeding a proton-emitting isomeric-state in Lu-151 have been observed for the first time. Comparison with state-of-the-art nonadiabatic quasiparticle calculations indicates an oblately deformed, 3/2(+) proton-emitting state with a quadrupole deformation of beta(2) = -0.11. The calculations suggest an increase in quadrupole deformation, to beta(2) = -0.18, with increasing spin which is understood in terms of the mixing of Nilsson states at the Fermi surface. It is also shown that the proton decay half-life is consistent with that from a 3/2(+) state with a quadrupole deformation of beta(2) = -0.12.
38.	Wang, F., et al. (författare) Reinvestigation of the excited states in the proton emitter Lu-151 : Particle-hole excitations across the N = Z=64 subshell 2017 Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 96:6 Tidskriftsartikel (refereegranskat)abstract The excited states of the proton emitter Lu-151 were reinvestigated in a recoil-decay tagging experiment at the Accelerator Laboratory of the University of Jyvaskyla (JYFL). The level scheme built on the ground state of 151Lu was updated with five new y-ray transitions. Large-scale shell model calculations were carried out in the model space consisting of the neutron and proton orbitals 0g(7/2), Id(5/2), Id(3/2), 2s(1/2), and Oh(1/2) with the optimized monopole interaction in order to interpret the experimental level scheme of Lu-151. It is found that the excitation energies of states above the 27/2(-) and 23/2(+) isomeric levels in Lu-151 can be sensitive to excitations from g(7/2) and d(5/2) to single-particle orbitals above N = Z = 64.
39.	Wang, F., et al. (författare) Spectroscopic factor and proton formation probability for the d3/2 proton emitter 151mLu 2017 Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 770, s. 83-87 Tidskriftsartikel (refereegranskat)abstract The quenching of the experimental spectroscopic factor for proton emission from the short-lived d3/2 isomeric state in 151mLu was a long-standing problem. In the present work, proton emission from this isomer has been reinvestigated in an experiment at the Accelerator Laboratory of the University of Jyväskylä. The proton-decay energy and half-life of this isomer were measured to be 1295(5) keV and 15.4(8) μs, respectively, in agreement with another recent study. These new experimental data can resolve the discrepancy in the spectroscopic factor calculated using the spherical WKB approximation. Using the R-matrix approach it is found that the proton formation probability indicates no significant hindrance for the proton decay of 151mLu.
40.	Andreyev, A. N., et al. (författare) New microsecond isomers in Bi-189,Bi-190 2001 Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 10:2, s. 129-133 Tidskriftsartikel (refereegranskat)abstract New microsecond isomers in the neutron-deficient isotopes Bi-189g,Bi-190 have been identified after in-flight separation by the velocity filter SHIP. The evaporation residues were identified on the basis of delayed recoil-gamma /X-ray, recoil-gamma /X-ray-alpha and excitation function measurements. The systematics of the [pi 1i(13/2)]13/2(+) excited states in the odd-mass Bi nuclei is discussed.
41.	Andreyev, A. N., et al. (författare) The discovery of a prolate-oblate-spherical shape triple of spin 0(+) states in the atomic nucleus Pb-186 2001 Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474 .- 1873-1554. ; 682, s. 482C-486C Tidskriftsartikel (refereegranskat)abstract Two excited J(pi)=0(+) states in Pb-186 populated in the a-decay of Po-190 have been identified through alpha -particle/conversion electron coincidences in an experiment at the velocity filter SHIP. The parent Po-190 nuclei have been produced in the Nd-142(Cr-52,4n)Po-190 complete fusion reaction, alpha -particle energies and branching ratios have been measured and hindrance factors were deduced. The observed states have been interpreted as the band heads of the known prolate and (yet unobserved) oblate rotational bands in Pb-186.
42.	Bark, R A, et al. (författare) Coexistence of triaxial and prolate shapes in Ir-171 1999 Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 657:2, s. 113-133 Tidskriftsartikel (refereegranskat)abstract Excited states in Ir-171 have been observed for the first time. Gamma-rays were assigned to the nucleus by the recoil-decay tagging method, The ground-state band has a structure consistent with an h(11/2) proton coupled to a core of large triaxial deformation. At high spins, a bandcrossing occurs which is interpreted as a change in shape to a prolate deformation, Band-mixing calculations are performed for Ir171-175. These show that shape-coexistence between triaxial and prolate states in these nuclei follows the same systematics found in their Pt and Os neighbours. The systematics are also compared with deformations calculated for Ir171-179 using the code "Ultimate Cranker". Dipole bands were also observed, but tilted axis cranking calculations suggest that they are associated with a collective rotation.
43.	Carroll, R. J., et al. (författare) Blurring the Boundaries : Decays of Multiparticle Isomers at the Proton Drip Line 2014 Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 112:9, s. 092501- Tidskriftsartikel (refereegranskat)abstract A multiparticle spin-trap isomer has been discovered in the proton-unbound nucleus 158 73 Ta 85. The isomer mainly decays by (h) over bar -ray emission with a half-life of 6.1d(1) mu s. Analysis of the gamma-ray data shows that the isomer lies 2668 keV above the known 9(+) state and has a spin 10h higher and negative parity. This 19(-) isomer also has an 8644(11) keV, 1.4(2)% alpha-decay branch that populates the 9(+) state in Lu-154. No proton-decay branch from the isomer was identified, despite the isomer being unbound to proton emission by 3261(14) keV. This remarkable stability against proton emission is compared with theoretical predictions, and the implications for the extent of observable nuclides are considered.
44.	Carroll, R. J., et al. (författare) Competing decay modes of a high-spin isomer in the proton-unbound nucleus 158Ta 2015 Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 46:3, s. 695-698 Tidskriftsartikel (refereegranskat)abstract An isomeric state at high spin and excitation energy was recently observed in the proton-unbound nucleus 158Ta. This state was observed to decay by both α and γ decay modes. The large spin change required to decay via γ-ray emission incurs a lifetime long enough for α decay to compete. The α decay has an energy of 8644(11) keV, which is among the highest observed in the region, a partial half-life of 440(70) μs and changes the spin by 11h. In this paper, additional evidence supporting the assignment of this α decay to the high-spin isomer in 158Ta will be presented.
45.	Cederwall, Bo, et al. (författare) Collective rotational-vibrational transition in the very neutron-deficient nuclei (171,172)-Pt 1998 Ingår i: Physics Letters B. - AMSTERDAM, NETHERLANDS : ELSEVIER SCIENCE. - 0370-2693 .- 1873-2445. ; 443:1-4, s. 69-76 Tidskriftsartikel (refereegranskat)abstract Excited states have been identified for the first time in very neutron deficient Pt-171.172 nuclei using the recoil-or-decay tagging technique. The ground-state band in Pt-172 has been established up to I-pi = 8+. A similar level sequence, presumably built on the I-pi = 13/2(+) state, is observed for Pt-171. The data are compared with theoretical calculations based on the mean field approach and the random phase approximation and are put into the context of the systematics of platinum isotopes. (C) 1998 Elsevier Science B.V. All rights reserved.
46.	Darby, I. G., et al. (författare) Decay of the high-spin isomer in Re-160 : Changing single-particle structure beyond the proton drip line 2011 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 695:1-4, s. 78-81 Tidskriftsartikel (refereegranskat)abstract A new high-spin isomeric state (t(1/2) = 2.8 +/- 0.1 mu s) in Re-160 has been identified. This high-spin isomer is unique in that it only decays by gamma-decay and not by proton or alpha-particle emission as is the case in every other proton emitter between Z = 64 and 80. Shell model calculations indicate how the convergence of the h(9/2) and f(7/2) neutron levels in this region could open up a gamma-decay path from the high-spin isomer to the low-spin ground state of 160Re. providing a natural explanation for this anomalous absence of charged-particle emission. The consequences of these observations for future searches for proton emission from even more exotic nuclei and in-beam spectroscopic studies are considered.
47.	Darby, I. G., et al. (författare) Precision measurements of proton emission from the ground states of Ta-156 and Re-160 2011 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 83:6, s. 064320- Tidskriftsartikel (refereegranskat)abstract The decays of the pi d(3/2) ground states of Ta-156 and Re-160 have been studied in detail using the GREAT spectrometer. More than 7000 Re-160 nuclei were produced in reactions of 290- and 300-MeV Ni-58 ions with an isotopically enriched Cd-106 target and separated in flight using the RITU separator. The proton and alpha decays of the pi d(3/2) level were confirmed and the half-life and branching ratios of this state were determined with improved precision to be t(1/2) = 611 +/- 7 mu s and b(p) = 89 +/- 1% and b(alpha) = 11 +/- 1%, respectively. The alpha-decay branch populated the ground state of Ta-156, allowing improved values for the proton-decay energy and half-life to be obtained (E-p = 1011 +/- 5 keV; t(1/2) = 106 +/- 4 ms). The beta decay of this level was identified for the first time and a branching ratio of b(beta) = 29 +/- 3% was deduced. The spectroscopic factors deduced from these measurements are compared with predictions.
48.	Doncel, Maria, et al. (författare) Lifetime measurements of excited states in W-162 and W-164 and the evolution of collectivity in rare-earth nuclei 2017 Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 95:4 Tidskriftsartikel (refereegranskat)abstract Lifetimes of the first excited 2(+) states in the extremely neutron- deficient W-162 and W-164 nuclei have been measured using the recoil distance Doppler shift technique. Experimental B(E2) data for the isotopic chains of hafnium, tungsten, and osmium, from the midshell region near the beta-stability line towards the N = 82 closed shell and the most neutron-deficient nuclides, are compared with predictions of nuclear deformations and 2(1)(+) -> 0(g.s)(.+) reduced transition strengths from different classes of state-of-the-art theoretical model calculations. The results reveal striking differences and deficiencies in the predictive power of current nuclear structure models.
49.	Ghazi Moradi, Farnaz, et al. (författare) High-spin study of 162Ta 2011 Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 84:6, s. 064312- Tidskriftsartikel (refereegranskat)abstract Excited states in the odd-odd neutron deficient nucleus (162)Ta (Z = 73, N = 89) have been studied for the first time. The gamma spectroscopy analysis using gamma - gamma - gamma coincidences revealed a strongly coupled rotational structure that was established up to large angular momentum states. The rotational band was assigned to the configuration pi h(11/2)[514]9/2 circle times nu i(13/2)[660]1/2 based on its rotational and electromagnetic properties. The data are interpreted within the framework of total Routhian surface calculations, which suggests an axially symmetric shape with a gamma-softminimum at beta(2) approximate to 0.16 and gamma approximate to 6 degrees. The crossing of the signature partners observed in heavier (N >= 91) odd-odd nuclides in this mass region is found to be absent at N = 89. This might be correlated with a change in S-band structure above the paired band crossing at these neutron numbers.
50.	Grahn, T., et al. (författare) Excited states and reduced transition probabilities in Os-168 2016 Ingår i: PHYSICAL REVIEW C. - : American Physical Society. - 2469-9985. ; 94:4 Tidskriftsartikel (refereegranskat)abstract The level scheme of the neutron-deficient nuclide Os-168 has been extended and mean lifetimes of excited states have been measured by the recoil distance Doppler-shift method using the JUROGAM gamma-ray spectrometer in conjunction with the IKP Koln plunger device. The 168Os. rays were measured in delayed coincidence with recoiling fusion-evaporation residues detected at the focal plane of the RITU gas-filled separator. The ratio of reduced transition probabilities B(E2; 4(1)(+)-> 2(1)(+))/B(E2; 2(1)(+)-> 0(1)(+)) is measured to be 0.34(18), which is very unusual for collective band structures and cannot be reproduced by interacting boson model (IBM-2) calculations based on the SkM* energy-density functional.

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