ADOPTED LEVELS for 193At
Author: M. Shamsuzzoha Basunia | Citation: Nucl. Data Sheets 143, 1 (2017) | Cutoff date: 31-Mar-2017
Full ENSDF file | Adopted Levels (PDF version)
| Q(β-)=-9110 keV 30 | S(n)= 11060 keV 40 | S(p)= -714 keV 24 | Q(α)= 7572 keV 7 | ||
| Reference: 2017WA10 |
| E(level) (keV) | Jπ(level) | T1/2(level) |
| 0.0 | (1/2+) | 28 ms +5-4 % α ≈ 100 |
| 5 10 | (7/2-) | 21 ms 5 % α ≈ 100 |
| 39 7 | (13/2+) | 27 ms +4-3 % α = 24 10 % IT = 76 10 |
E(level): From 2003Ke08, based on α-particle energy difference.
T1/2(level): Values from 2003Ke08
Additional Level Data and Comments:
| E(level) | Jπ(level) | T1/2(level) | Comments |
| 0.0 | (1/2+) | 28 ms +5-4 % α ≈ 100 | This level decays by an 7235-keV α particle to the 187 keV 9 1/2+ level in 189Bi (2003Ke08). Based on the properties of this transition, 2003Ke08 propose this level as the 193At g.s. In the 189Bi Adopted Levels, 1/2+ state located at 184 keV 8 (2017Jo05). E(level): This level decays by an 7235-keV α particle to the 187 keV 9 1/2+ level in 189Bi (2003Ke08). Based on the properties of this transition, 2003Ke08 propose this level as the 193At g.s. In the 189Bi Adopted Levels, 1/2+ state located at 184 keV 8 (2017Jo05). |
| 5 | (7/2-) | 21 ms 5 % α ≈ 100 | Two α branches deexcite this state to levels in 189Bi: a) E(α)=7325 5 keV, I(α)=98 2 %, HF=1.1 3, to the (7/2-) 100-keV level in 189Bi; b) E(α)=7423 5 keV, I(α)=2 2 %, HF=64 64, to the 189Bi g.s. The hindrance factors imply an ΔL=0 unhindered α transition in the first case. Note that the quoted HF values are as given in 2003Ke08, based on their reinterpretation of the observed values, by assuming the existence of an unobserved ≈34-keV γ ray connecting the 193At 13/2+ isomeric state at 39 7 keV, with the 5-keV isomeric level. E(level): Two α branches deexcite this state to levels in 189Bi: a) E(α)=7325 5 keV, I(α)=98 2 %, HF=1.1 3, to the (7/2-) 100-keV level in 189Bi; b) E(α)=7423 5 keV, I(α)=2 2 %, HF=64 64, to the 189Bi g.s. The hindrance factors imply an ΔL=0 unhindered α transition in the first case. Note that the quoted HF values are as given in 2003Ke08, based on their reinterpretation of the observed values, by assuming the existence of an unobserved ≈34-keV γ ray connecting the 193At 13/2+ isomeric state at 39 7 keV, with the 5-keV isomeric level. |
| 39 | (13/2+) | 27 ms +4-3 % α = 24 10 % IT = 76 10 | This level depopulates via a 7106 5 keV α decay to the 13/2+ 358-keV state in 189Bi. The hindrance factor calculated in 2003Ke08 for this transition, assuming an 100% α branch, is 0.24 4. To explain this anomalously low value of HF, 2003Ke08 propose that there exists an IT decay branch deexciting this state to the 7/2- level, taking about 76 10 % of the decay strength, and thus leaving 24 10 % for the α intensity. The unobserved ≈34-keV IT branch would probably have an E3 character, consistent with the observed half-life for the level. E(level): This level depopulates via a 7106 5 keV α decay to the 13/2+ 358-keV state in 189Bi. The hindrance factor calculated in 2003Ke08 for this transition, assuming an 100% α branch, is 0.24 4. To explain this anomalously low value of HF, 2003Ke08 propose that there exists an IT decay branch deexciting this state to the 7/2- level, taking about 76 10 % of the decay strength, and thus leaving 24 10 % for the α intensity. The unobserved ≈34-keV IT branch would probably have an E3 character, consistent with the observed half-life for the level. |
Identification: parent of 189Bi; produced by heavy ion induced fusion (56Fe+141Pr, E=265 MeV) (1995Le15)
Levels: Level properties from 193At α decay (2003Ke08). Levels populated by the 141Pr(56Fe,4nγ) reaction, at E(target)=264-272 MeV; recoil fragment mass separation; measurement using recoil-tagged α-α and α-γ coincidences, and considering α-decay links to levels in the daughter nuclides 189Bi and 185Tl.