| 1. |
|
|
| 2. |
- 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.
|
|
| 3. |
- Tanvir, N. R., et al.
(författare)
-
A γ-ray burst at a redshift of z~8.2
- 2009
-
Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 461, s. 1254-1257
-
Tidskriftsartikel (refereegranskat)abstract
- Long-duration γ-ray bursts (GRBs) are thought to result from the explosions of certain massive stars, and some are bright enough that they should be observable out to redshifts of z>20 using current technology. Hitherto, the highest redshift measured for any object was z = 6.96, for a Lyman-α emitting galaxy. Here we report that GRB090423 lies at a redshift of z~8.2, implying that massive stars were being produced and dying as GRBs ~630Myr after the Big Bang. The burst also pinpoints the location of its host galaxy.
|
|
| 4. |
- Grahn, T., et al.
(författare)
-
Collectivity and configuration mixing in Pb186,188 and Po194
- 2006
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 97:6
-
Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of prolate intruder states in Pb186 and oblate intruder states in Po194 have been determined by employing, for the first time, the recoil-decay tagging technique in recoil distance Doppler-shift lifetime measurements. In addition, lifetime measurements of prolate states in Pb188 up to the 8+ state were carried out using the recoil-gating method. The B(E2) values have been deduced from which deformation parameters |β2|=0.29(5) and |β2|=0.17(3) for the prolate and the oblate bands, respectively, have been extracted. The results also shed new light on the mixing between different shapes.
|
|
| 5. |
- Herzberg, R-D, et al.
(författare)
-
Isomer spectroscopy in No-254
- 2006
-
Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T125, s. 73-77
-
Tidskriftsartikel (refereegranskat)abstract
- Isomeric states in No-254 were investigated using a calorimetric method. Two different isomers were found with half-lives of T-1/2 = 266 +/- 2 ms and T-1/2 = 184 +/- 3 mu s, respectively. The dominant decay path of the 184 mu s isomer proceeds via states feeding the longer-lived 266 ms isomer. The 266 ms isomer in turn decays via a two-quasi-particle K = 3 band to the ground-state band. The full decay path was observed with the GREAT spectrometer located at the focal plane of the gas-filled separator RITU at the Accelerator Laboratory in Jyvskyl. This work sheds light on the two-quasi-particle structure in this transfermium nucleus.
|
|
| 6. |
|
|
| 7. |
- Joss, D. T., et al.
(författare)
-
Yrast states and band crossings in the neutron-deficient platinum isotopes Pt169-173
- 2006
-
Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:1
-
Tidskriftsartikel (refereegranskat)abstract
- The yrast states in the light platinum isotopes Pt169-173 have been investigated in a recoil-decay tagging experiment using the JUROGAM gamma-ray spectrometer in conjunction with the RITU gas-filled recoil separator and the GREAT tagging spectrometer. Gamma-ray transitions have been established for the first time in the odd-N isotopes, Pt-169 and Pt-173, and the yrast sequences in Pt-170 and Pt-172 have been extended. We discuss the possibility that the weakly deformed yrast structures of Pt-170, Pt-172, and Pt-173 are crossed by a deformed intruder configuration at spin similar to 8h.
|
|
| 8. |
- Joss, D. T., et al.
(författare)
-
Yrast structures in the light Pt isotopes Pt169-173
- 2005
-
Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1715-S1718
-
Tidskriftsartikel (refereegranskat)abstract
- The exploitation of the recoil-decay tagging (RDT) technique has reinvigorated experimental investigations of the shape coexistence phenomenon in heavy neutron-deficient nuclei. In a recent experiment using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator, excited states have been investigated in the light platinum isotopes. In addition to extending the yrast sequences in Pt-170 and Pt-172, the first observation of excited states in the odd-N isotopes, Pt-169 and Pt-173, is reported. The bands are discussed in terms of trends in level excitation energies as a function of neutron number.
|
|
| 9. |
- Lagergren, Karin, et al.
(författare)
-
High-spin states in the proton-unbound nucleus Re-161
- 2006
-
Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:2, s. 024316-
-
Tidskriftsartikel (refereegranskat)abstract
- Excited states in Re-161 were populated using the Cd-106(Ni-58, p2n) reaction at a beam energy of 270 MeV, resulting in the first observation of gamma rays emitted from this nucleus. The reaction products were separated from scattered beam and fission fragments by the gas-filled recoil separator RITU, and were implanted in the double-sided silicon strip detectors of the GREAT spectrometer. Prompt gamma rays were detected by the JUROGAM Ge detector array and were assigned to Re-161 based on alpha- and proton-decay tagging of the implanted reaction products. The near-yrast high-spin level structure, which was delineated to spins around 39/2, is discussed in the context of the total Routhian surface formalism. The level scheme is interpreted in terms of the alignment of h(9/2)/f(7/2) neutrons at lower spins, followed by excitations involving the pi h(11/2) subshell at higher spins.
|
|
| 10. |
- Lynch, David K., et al.
(författare)
-
NOVA V2362 CYGNI (NOVA CYGNI 2006): SPITZER, SWIFT, AND GROUND-BASED SPECTRAL EVOLUTION
- 2008
-
Ingår i: Astronomical Journal. - 1538-3881 .- 0004-6256. ; 136:number 5, 2008 November, s. 1815-1827
-
Tidskriftsartikel (refereegranskat)abstract
- Nova V2362 Cygni has undergone a number of very unusual changes. Ground-based spectroscopy initially revealed a normal sequence of events: the object faded and its near-infrared emission lines gradually shifted to higher excitation conditions until about day 100 when the optical fading reversed and the object slowly brightened. This was accompanied by a rise in the Swift X-ray telescope flux and a sudden shift in excitation of the visible and IR spectrum back to low levels. The new lower excitation spectrum revealed broad line widths and many P-Cygni profiles, all indicative of the ejection of a second shell. Eventually, dust formed, the X-ray brightness—apparently unaffected by dust formation—peaked and then declined, and the object faded at all wavelengths. The Spitzer dust spectra revealed a number of solid-state emission features that, at this time, are not identified.
|
|
