ADOPTED LEVELS for 231Np
Authors: Balraj Singh, Jagdish K. Tuli, and Edgardo Browne | Citation: Nucl. Data Sheets 185, 560 (2022) | Cutoff date: 31-Aug-2022
Full ENSDF file | Adopted Levels (PDF version)
Q(β-)=-2680 keV 60 | S(n)= 7680 keV 80 | S(p)= 3280 keV 50 | Q(α)= 6370 keV 50 | ||
Reference: 2021WA16 |
References: | |||
A | 235Am α decay (10.3 M) |
E(level) (keV) | XREF | Jπ(level) | T1/2(level) |
0 | A | (5/2-) | 48.8 m 2 % ε ≈ 98 % α ≈ 2 |
Additional Level Data and Comments:
E(level) | Jπ(level) | T1/2(level) | Comments |
0 | (5/2-) | 48.8 m 2 % ε ≈ 98 % α ≈ 2 | %α=2.0 if α to g.s. of 227Pa is favored. Measurements of 1950Ma14 established the α-decay mode, but only %ε/%α<100 (implying %α>1%) could be determined in their experiment. Systematics suggest %α<10. Theoretical calculations of T1/2(β)>100 s and T1/2(α)=7.4×105s (2019Mo01) suggest dominant ε+β+ decay mode. E(level): %α=2.0 if α to g.s. of 227Pa is favored. Measurements of 1950Ma14 established the α-decay mode, but only %ε/%α<100 (implying %α>1%) could be determined in their experiment. Systematics suggest %α<10. Theoretical calculations of T1/2(β)>100 s and T1/2(α)=7.4×105s (2019Mo01) suggest dominant ε+β+ decay mode. |
1950Ma14: 231Np produced and identified in 235U(d,6n),E=45-100 MeV at Berkeley, followed by chemical separation. From observation of α spectra from 231Np decay, parent-daughter correlation of 231Np and 227Pa was established. Measured half-life of the decay of 231Np
1973We08: 231Np produced in 233U(d,4n). Measured Eγ, Iγ, half-life of the decay of 231Np
Theoretical calculations: consult the NSR database (www.nndc.bnl.gov/nsr/) for 23 primary references for the decay characteristics of 231Np, and two for nuclear structure. These references are listed in ’document’ records, which can be accessed through on-line ENSDF database at www.nndc.bnl.gov/ensdf/
Q-value: S(2n)=14320 110, S(2p)=8850 50, Q(ε)=1820 50 (2021Wa16)