ADOPTED LEVELS, GAMMAS for 229Ac
Authors: F.G. Kondev, J.K. Tuli and E. Browne | Citation: Nucl. Data Sheets 208, 397 (2026) | Cutoff date: 23-Oct-2025
Full ENSDF file | Adopted Levels (PDF version)
| Q(β-)=1104 keV 12 | S(n)= 6276 keV 12 | S(p)= 5539 keV 12 | Q(α)= 4444 keV 17 | ||
| Reference: 2021WA16 |
| References: | |||
| A | 229Ra β- decay | B | 232Th(p,α) |
| C | 230Th(t,α) | ||
| E(level) (keV) | XREF | Jπ(level) | T1/2(level) | E(γ) (keV) | I(γ) | Final Levels | |
| 0.0 | A C | 3/2+ | 62.7 m 5 % β- = 100 | ||||
| 7.0 5 | A C | (5/2+) | 6.6 7 S | 100 | 0.0 | 3/2+ | |
| 21.4 5 | AB | (7/2+) | 14.5 3 | 100 | 7.0 | (5/2+) | |
| 25.9 5 | A C | (9/2+) | 18.8 3 | 100 | 7.0 | (5/2+) | |
| 69.8 4 | A C | (5/2-) | 63.0 5 69.6 5 | | 7.0 0.0 | (5/2+) 3/2+ | |
| 91 5 | BC | (13/2)+ | |||||
| 104.3 4 | A C | (3/2-) | 104.5 5 | 100 | 0.0 | 3/2+ | |
| 119.8 5 | A C | (7/2-) | 15.6 3 93.6 5 98.5 5 | | 104.3 25.9 21.4 | (3/2-) (9/2+) (7/2+) | |
| 141.5 5 | A | 21.8 3 | 100 | 119.8 | (7/2-) | ||
| 151 5 | BC | 1/2+ | |||||
| 164.0 5 | ABC | (7/2)- | 22.5 3 44.0 5 94.1 5 | | 141.5 119.8 69.8 | (7/2-) (5/2-) | |
| 174.8 6 | A | 55.0 5 | 100 | 119.8 | (7/2-) | ||
| 189.0 7 | ABC | (3/2)+ | 47.5 5 | 100 | 141.5 | ||
| 222.0 7 | A | 102.2 5 | 100 | 119.8 | (7/2-) | ||
| 280.9 6 | A C | 106.1 5 161.1 5 | | 174.8 119.8 | (7/2-) | ||
| 293 3 | B | ||||||
| 335.5 7 | ABC | (3/2)+ | 171.5 5 | 100 | 164.0 | (7/2)- | |
| 368 3 | BC | (5/2+) | |||||
| 422 4 | C | ||||||
| 464 4 | C | ||||||
| 489 4 | C | ||||||
| 595 3 | BC | ||||||
| 629 4 | BC | ||||||
| E(level) (keV) | XREF | Jπ(level) | T1/2(level) | E(γ) (keV) | I(γ) | Final Levels | |
| 654 4 | C | ||||||
| 825 6 | C | ||||||
| 850 6 | B | ||||||
| 926 5 | BC | (11/2-) | |||||
| 1001 5 | BC | (5/2)- | |||||
| 1021 8 | C | ||||||
| 1044 5 | B | ||||||
| 1111 6 | BC | ||||||
| 1173 6 | BC | ||||||
| 1245 6 | BC | ||||||
E(level): From a least-squares fit to Eγ, unless otherwise stated
Jπ(level): From comparison of experimental (t,α) cross-sections with calculated values (1977Th04), unless otherwise stated
E(γ): From 229Ra β- decay.
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | Final Levels | ||
| Band 1 - π3/2[651] band | |||||||
| 0.0 | 3/2+ | 62.7 m 5 % β- = 100 | |||||
| 7.0 5 | (5/2+) | 6.6 7 S | 100 | 0.0 | 3/2+ | ||
| 21.4 5 | (7/2+) | 14.5 3 | 100 | 7.0 | (5/2+) | ||
| 25.9 5 | (9/2+) | 18.8 3 | 100 | 7.0 | (5/2+) | ||
| 91 5 | (13/2)+ | ||||||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | Final Levels | ||
| Band 2 - π1/2[530] band | |||||||
| 104.3 4 | (3/2-) | ||||||
| 164.0 5 | (7/2)- | 22.5 3 44.0 5 94.1 5 | | 141.5 119.8 69.8 | (7/2-) (5/2-) | ||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | Final Levels | ||
| Band 3 - π1/2[400] band | |||||||
| 151 5 | 1/2+ | ||||||
| 189.0 7 | (3/2)+ | 47.5 5 | 100 | 141.5 | |||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | Final Levels | ||
| Band 4 - π3/2[402] band | |||||||
| 335.5 7 | (3/2)+ | ||||||
| 368 3 | (5/2+) | ||||||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | Final Levels | ||
| Band 5 - π5/2[532] band | |||||||
| 69.8 4 | (5/2-) | ||||||
| 119.8 5 | (7/2-) | 15.6 3 93.6 5 98.5 5 | | 104.3 25.9 21.4 | (3/2-) (9/2+) (7/2+) | ||
Additional Level Data and Comments:
| E(level) | Jπ(level) | T1/2(level) | Comments |
| 0.0 | 3/2+ | 62.7 m 5 % β- = 100 | Q=+2.4789 54 (2025Li31), μ=+2.00682 33 (2025Li31) δ<r2>(229Ac,227Ac)=0.123 fm2 8 (stat) 12 (syst) (2025Li31). Other: δ<r2>(215Ac,229Ac)=+1.67 fm2 1 (stat) 9 (syst) in 2019Ve07. E(level): δ<r2>(229Ac,227Ac)=0.123 fm2 8 (stat) 12 (syst) (2025Li31). Other: δ<r2>(215Ac,229Ac)=+1.67 fm2 1 (stat) 9 (syst) in 2019Ve07. π3/2[651] band. δ<r2>(229Ac,227Ac)=0.123 fm2 8 (stat) 12 (syst) (2025Li31). Other: δ<r2>(215Ac,229Ac)=+1.67 fm2 1 (stat) 9 (syst) in 2019Ve07. E(level): δ<r2>(229Ac,227Ac)=0.123 fm2 8 (stat) 12 (syst) (2025Li31). Other: δ<r2>(215Ac,229Ac)=+1.67 fm2 1 (stat) 9 (syst) in 2019Ve07. π3/2[651] band. |
| 7.0 | (5/2+) | XREF: C(5). E(level): π3/2[651] band. | |
| 21.4 | (7/2+) | XREF: B(36). E(level): π3/2[651] band. | |
| 25.9 | (9/2+) | E(level): π3/2[651] band. | |
| 69.8 | (5/2-) | E(level): π5/2[532] band. | |
| 91 | (13/2)+ | E(level): π3/2[651] band. From 230Th(t,α). | |
| 104.3 | (3/2-) | XREF: C(102). E(level): π1/2[530] band. | |
| 119.8 | (7/2-) | E(level): π5/2[532] band. | |
| 151 | 1/2+ | E(level): π1/2[400] band. From 230Th(t,α). | |
| 164.0 | (7/2)- | XREF: B(166)C(165). E(level): π1/2[530] band. | |
| 189.0 | (3/2)+ | XREF: B(193)C(191). E(level): π1/2[400] band. | |
| 280.9 | XREF: C(283). | ||
| 293 | E(level): From 232Th(p,α). | ||
| 335.5 | (3/2)+ | E(level): π3/2[402] band. | |
| 368 | (5/2+) | XREF: C(366). E(level): π3/2[402] band. From 232Th(p,α). | |
| 422 | E(level): From 230Th(t,α). | ||
| 464 | E(level): From 230Th(t,α). | ||
| 489 | E(level): From 230Th(t,α). | ||
| 595 | XREF: C(598). E(level): From 232Th(p,α). | ||
| 629 | XREF: C(623). E(level): From 232Th(p,α). | ||
| 654 | E(level): From 230Th(t,α). | ||
| 825 | E(level): From 230Th(t,α). | ||
| 850 | E(level): From 232Th(p,α). | ||
| 926 | (11/2-) | XREF: C(930). E(level): From 232Th(p,α). | |
| 1001 | (5/2)- | XREF: C(1004). E(level): From 232Th(p,α). | |
| E(level) | Jπ(level) | T1/2(level) | Comments |
| 1021 | E(level): From 230Th(t,α). | ||
| 1044 | E(level): From 232Th(p,α). | ||
| 1111 | E(level): From 232Th(p,α). | ||
| 1173 | XREF: C(1167). E(level): From 232Th(p,α). | ||
| 1245 | XREF: C(1249). E(level): From 232Th(p,α). |
| E(level) | E(gamma) | Comments |
| 7.0 | 6.6 | E(γ): Not seen experimentally. Eγ from γ-ray energy difference, depopulating the 69.8-keV level. |
| 335.5 | 171.5 | E(γ): The transition would be Mult.=M2 and long lifetime would be expected |