| 1. |
- Kanungo, R., et al.
(författare)
-
Exploring the anomaly in the interaction cross section and matter radius of 23O
- 2011
-
Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813 .- 1089-490X. ; 84:6, s. art. no. 061304(R)-
-
Tidskriftsartikel (refereegranskat)abstract
- New measurements of the interaction cross sections of 22,23O at 900A MeV performed at the GSI, Darmstadt are reported that address the unsolved puzzle of the large cross section previously observed for 23O. The matter radii for these oxygen isotopes extracted through a Glauber model analysis are in good agreement with the new predictions of the ab initio coupled-cluster theory reported here. They are consistent with a 22O+neutron description of 23O as well.
|
|
| 2. |
- Kanungo, R., et al.
(författare)
-
Matter radii of 32-35Mg
- 2011
-
Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813 .- 1089-490X. ; 83:2
-
Tidskriftsartikel (refereegranskat)abstract
- The interaction cross sections of Mg32-35 at 900A MeV have been measurmed using the fragment separator at GSI. The deviation from the r(0)A(1/3) trend is slightly larger for Mg-35, signaling the possible formation of a longer tail in the neutron distribution for Mg-35. The radii extracted from a Glauber model analysis with Fermi densities are consistent with models predicting the development of neutron skins.
|
|
| 3. |
- Kanungo, R., et al.
(författare)
-
One-Neutron Removal Measurement Reveals O-24 as a New Doubly Magic Nucleus
- 2009
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 102:15
-
Tidskriftsartikel (refereegranskat)abstract
- The first measurement of the momentum distribution for one-neutron removal from O-24 at 920A MeV performed at GSI, Darmstadt is reported. The observed distribution has a width (FWHM) of 99 +/- 4 MeV/c in the projectile rest frame and a one-neutron removal cross section of 63 +/- 7 mb. The results are well explained with a nearly pure 2s(1/2) neutron spectroscopic factor of 1.74 +/- 0.19 within the eikonal model. This large s-wave probability shows a spherical shell closure thereby confirming earlier suggestions that O-24 is a new doubly magic nucleus.
|
|
| 4. |
- Nociforo, C., et al.
(författare)
-
One-neutron removal reactions on Al isotopes around the N=20 shell closure
- 2012
-
Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X .- 2469-9985 .- 2469-9993. ; 85:4, s. 044312-1-044312-10
-
Tidskriftsartikel (refereegranskat)abstract
- The one-neutron removal cross sections of neutron-rich Al isotopes and longitudinal momentum distributions of the residues have been measured for A=33 to 36 at relativistic energies (≈900 MeV/u). The inclusive data have been interpreted within the eikonal approximation. The evolution of the single-particle occupancy in the ground state of 33,34,35Al has been studied and compared with shell model predictions. The inferred 2s1/2 neutron occupancy in the 33Al ground-state wave function is 20% to 40% lower than the predicted one. The inclusive data do not exclude the presence of intruder states. Some intruder l=1 occupancy is found in 34Al, similarly to 33Mg. The single-particle 1f7/2 occupancy shows a gradual increase at N=22. Correspondingly, a decrease of the 1d3/2 strength has been observed.
|
|
| 5. |
- Nociforo, C., et al.
(författare)
-
Shell Closure N=16 in O-24
- 2009
-
Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1165, s. 90-93 461
-
Konferensbidrag (refereegranskat)abstract
- Advanced nuclear structure models predict the presence of the shell closures N=14, 16 in neutron-rich O isotopes rather than N=20. Spectroscopic investigations performed at the neutron drip line have recently confirmed such predictions showing that the O-24 is a doubly magic nucleus (Z=8, N=16). Predictions within the shell model calculation for the O-23,O-24 ground state have been confirmed measuring their spectroscopic factors. Results obtained in one-neutron removal reactions performed by using in-flight radioactive ion beams produced at the Fragment Separator FRS of GSI are reported.
|
|
| 6. |
- Andreyev, A. N., et al.
(författare)
-
alpha-decay of the new isotope Po-187 : Probing prolate structures beyond the neutron mid-shell at N=104
- 2006
-
Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 73:4, s. 044324-
-
Tidskriftsartikel (refereegranskat)abstract
- The new neutron-deficient isotope Po-187 has been identified in the complete fusion reaction Ti-46+Sm-144 -> Po-187+3n at the velocity filter SHIP. Striking features of the Po-187 alpha decay are the strongly-hindered decay to the spherical ground state and unhindered decay to a surprisingly low-lying deformed excited state at 286 keV in the daughter nucleus Pb-183. Based on the potential energy surface calculations, the Po-187 ground state and the 286 keV excited state in Pb-183 were interpreted as being of prolate origin. The systematic deviation of the alpha-decay properties in the lightest odd-A Po isotopes relative to the smooth behavior in the even-A neighbors is discussed. Improved data for the decay of Bi-187(m,g) were also obtained.
|
|
| 7. |
- Andreyev, A. N., et al.
(författare)
-
alpha decay of the new isotopes Rn-193,Rn-194
- 2006
-
Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:6, s. 064303-
-
Tidskriftsartikel (refereegranskat)abstract
- The new neutron-deficient isotopes Rn-193,Rn-194 have been identified in the complete fusion reaction Cr-52+Sm-144 -> Rn-196(*) at the velocity filter SHIP. The alpha-decay energy and half-life value of Rn-194 were determined to be E-alpha=7700(10) keV and T-1/2=0.78(16) ms, respectively. For Rn-193 the half-life of T-1/2=1.15(27) ms and two alpha lines at E-alpha 1=7685(15) keV, I-alpha 1=74(20)% and E-alpha 2=7875(20) keV, I-alpha 2=26(12)% were found. The decay pattern of Rn-193, which is substantially different from that of the heavier odd-A Rn isotopes, provides first experimental evidence for the long-predicted deformation in the very neutron-deficient Rn nuclei.
|
|
| 8. |
- Andreyev, A. N., et al.
(författare)
-
Signatures of the Z=82 shell closure in alpha-decay process
- 2013
-
Ingår i: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 110:24
-
Tidskriftsartikel (refereegranskat)abstract
- In recent experiments at the velocity filter Separator for Heavy Ion reaction Products (SHIP) (GSI, Darmstadt), an extended and improved set of α-decay data for more than 20 of the most neutron-deficient isotopes in the region from lead to thorium was obtained. The combined analysis of this newly available α-decay data, of which the Po186 decay is reported here, allowed us for the first time to clearly show that crossing the Z=82 shell to higher proton numbers strongly accelerates the α decay. From the experimental data, the α-particle formation probabilities are deduced following the Universal Decay Law approach. The formation probabilities are discussed in the framework of the pairing force acting among the protons and the neutrons forming the α particle. A striking resemblance between the phenomenological pairing gap deduced from experimental binding energies and the formation probabilities is noted. These findings support the conjecture that both the N=126 and Z=82 shell closures strongly influence the α-formation probability.
|
|
| 9. |
- Antalic, S., et al.
(författare)
-
The new isotopes in Po-Rn region
- 2007
-
Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 38:4, s. 1557-1560
-
Tidskriftsartikel (refereegranskat)abstract
- This contribution reviews the results of the recent experiments at the velocity filter SHIP in GSI Darmstadt obtained in the region of neutron deficient isotopes from lead to radon. The data for new very neutron-deficient isotopes Po-187, Rn-193,Rn-194 and their decay properties are presented. The isotopes were produced and identified in the complete fusion reactions Ti-46+Sm-144 -> Po-187+3n and Cr-52+Sm-144 -> Rn-194,Rn-193+2,3n.
|
|
| 10. |
- Cox, D. M., et al.
(författare)
-
Spectroscopy along flerovium decay chains. II. Fine structure in odd-A 289Fl
- 2023
-
Ingår i: Physical Review C. - 2469-9985. ; 107:2
-
Tidskriftsartikel (refereegranskat)abstract
- Fifteen correlated α-decay chains starting from the odd-A superheavy nucleus 289Fl were observed following the fusion-evaporation reaction 48Ca+244Pu. The results call for at least two parallel α-decay sequences starting from at least two different states of 289Fl. This implies that close-lying levels in nuclei along these chains have quite different spin-parity assignments. Further, observed α-electron and α-photon coincidences, as well as the α-decay fine structure along the decay chains, suggest a change in the ground-state spin assignment between 285Cn and 281Ds. Our experimental results, on the excited level structure of the heaviest odd-N nuclei to date, provide a direct testing ground for theory. This is illustrated by comparison with new nuclear structure calculations based on the symmetry-conserving configuration mixing theory.
|
|
