| 1. |
- Ruchowska, E., et al.
(författare)
-
Nuclear structure of Th-229
- 2006
-
Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 73:4
-
Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of excited states in Th-229, populated in the beta decay of Ac-229, have been measured using the advanced time-delayed beta gamma gamma(t) method. Half-lives of 14 states have been determined including 11 of them for the first time. Twenty-seven new gamma lines have been introduced into the beta-decay scheme of Ac-229 based on results of gamma gamma coincidence measurements. Reduced transition probabilities have been determined for more than 70 gamma transitions in Th-229. Average parallel to D-0 parallel to values of 0.029(1), 0.077(3), and 0.024(5) e fm have been deduced for the lowest K-pi=1/2(+/-),3/2(+/-), and 5/2(+/-) parity partner bands, respectively. Excited states in Th-229 and experimental transition rates have been interpreted within the quasiparticle-plus-phonon model. The half-life of the 3.5-eV, 3/2(+) isomeric state is predicted to be about 10 h. Potential energy surfaces on the (beta(2),beta(3)) plane for the lowest single quasiparticle configurations in Th-229 have been calculated using the Strutinsky method.
|
|
| 2. |
- Mach, H., et al.
(författare)
-
New structure information on Mg-30, Mg-31 and Mg-32
- 2005
-
Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 25, s. 105-109
-
Konferensbidrag (refereegranskat)abstract
- The fast timing beta gamma gamma(t) method was applied to investigate the level lifetimes in Mg-30,Mg-31,Mg-32. Levels in Mg have been populated in beta and beta-delayed neutron emission of Na, at the ISOLDE facility. From the gamma gamma coincidences a number of new states have been identified and new level schemes were constructed for 30 31,32 Mg. The following preliminary half lives have been determined: T-1/2 = 3.9(4) ns for the 1789 keV state in Mg-30, T-1/2 = 133(8) ps and 10.5(8) us for the 221 keV and 461 keV states in Mg-31, respectively, and T1/2 = 16(4) ps for the 885 keV level in 32Mg. The 1789 keV level was established as a candidate for the intruder 0(+) configuration in Mg-30 with a possible strong E0 branch to the ground state.
|
|
| 3. |
- Olaizola, B., et al.
(författare)
-
High-sensitivity study of levels in Al-30 following beta decay of Mg-30
- 2016
-
Ingår i: PHYSICAL REVIEW C. - 2469-9985 .- 2469-9993. ; 94:5
-
Tidskriftsartikel (refereegranskat)abstract
- gamma-ray and fast-timing spectroscopy were used to study levels in Al-30 populated following the beta(-) decay of Mg-30. Five new transitions and three new levels were located in Al-30. A search was made to identify the third 1(+) state expected at an excitation energy of similar to 2.5 MeV. Two new levels were found, at 3163.9 and 3362.5 keV, that are firm candidates for this state. Using the advanced time-delayed (ATD) beta gamma gamma (t) method we have measured the lifetime of the 243.8-keV state to be T-1/2 = 15(4) ps, which implies that the 243.8-keV transition is mainly of M1 character. Its fast B(M1; 2(+) -> 3(+)) value of 0.10(3) W.u. is in very good agreement with the USD shell-model prediction of 0.090 W.u. The 1801.5-keV level is the only level observed in this study that could be a candidate for the second excited 2(+) state.
|
|
| 4. |
- Mach, Henryk, et al.
(författare)
-
Ultrafast-timing lifetime measurements in Ru-94 and Pd-96 : Breakdown of the seniority scheme in N=50 isotones
- 2017
-
Ingår i: PHYSICAL REVIEW C. - : American Physical Society. - 2469-9985. ; 95:1
-
Tidskriftsartikel (refereegranskat)abstract
- The advanced time-delayed gamma gamma(t) method has been applied to determine half-lives of low-lying states in the N = 50 isotones Ru-94 and Pd-96. The inferred experimental E2 strengths for the 4(+) -> 2(+) transitions in the two nuclei show a dramatic deviation with respect to the shell model predictions in the (f(5/2), p, g(9/2)) proton hole space in Sn-100. The anomalous behavior can be ascribed to a breakdown of the seniority quantum number in the pi g(9/2)(n) configuration due to particle-hole excitations across the N = Z = 50 shell as confirmed by large-scale shell model calculations.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Ruchowska, E., et al.
(författare)
-
Quenching of the E1 strength in Nd-149
- 2010
-
Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 45:1, s. 1-10
-
Tidskriftsartikel (refereegranskat)abstract
- Lifetime measurements of excited states in Nd-149 have been performed using the advanced time-delayed beta gamma gamma(t) method. Half-lives of 14 excited states in Nd-149 have been determined for the first time or measured with higher precision. Twelve new gamma-lines and 5 new levels have been introduced into the decay scheme of Pr-149 based on results of the gamma gamma coincidence measurements. Reduced transition probabilities have been determined for 40 gamma-transitions in Nd-149. Configuration assignments for 6 rotational bands in Nd-149 are proposed. Enhanced E1 transitions indicate that the ground-state band and the band built on the 332.9 keV level constitute a pair of the K-pi = 5/2(+/-) parity doublet bands. Potential energy surfaces on the (beta(2),beta(3))-plane have been calculated for the lowest single quasi-particle configurations in Nd-149 using the Strutinski method and the axially deformed Woods-Saxon potential. The predicted occurrence of the octupole-deformed K = 5/2 configuration is in agreement with experiment. Unexpectedly low vertical bar D-0 vertical bar values obtained for the K-pi = 5/2(+/-) parity doublet bands may result from cancellation between the proton and neutron shell correction contributions to vertical bar D-0 vertical bar.
|
|
| 9. |
|
|
| 10. |
|
|
