ADOPTED LEVELS, GAMMAS for 242Np
Authors: M.J. Martin, C.D. Nesaraja | Citation: Nucl. Data Sheets 186, 261 (2022) | Cutoff date: 31-Dec-2021
Full ENSDF file | Adopted Levels (PDF version)
| Q(β-)=2.70×103 keV 20 | S(n)= 4.97×103 keV 22 | S(p)= 6070 keV SY | Q(α)= 4.10×103 keV 20 | ||
| Reference: 2021WA16 |
| References: | |||
| A | 242U β- decay | ||
| E(level) (keV) | XREF | Jπ(level) | T1/2(level) | E(γ) (keV) | I(γ) | M(γ) | Final Levels | |
| 0.0 | A | (1+) | 2.2 m 2 % β- = 100 | |||||
| 55.58 6 ? | A | (1-,0-) | 55.58 6 | 100 | E1 | 0.0 | (1+) | |
| 67.60 5 ? | A | (1-,0-) | 67.60 5 | 100 | E1 | 0.0 | (1+) | |
| 293.9 1 ? | A | 226.3 1 238.2 1 | 50 25 100 50 | 67.60 55.58 | (1-,0-) (1-,0-) | |||
| 329.7 1 ? | A | (1,0) | 274.2 2 329.7 1 | 15 6 100 7 | 55.58 0.0 | (1-,0-) (1+) | ||
| 598.3 3 ? | A | (1,0) | 304.5 2 530.6 2 | 100 22 59 30 | 293.9 67.60 | (1-,0-) | ||
| 640.6 2 ? | A | (1+,0+) | 572.9 1 585.0 1 | 97 6 100 6 | 67.60 55.58 | (1-,0-) (1-,0-) | ||
| 0.0+X | (6+) | 5.5 m 1 % β- = 100 | ||||||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) (keV) | Multipolarity | Conversion Coefficient | Additional Data |
| 55.58 | (1-,0-) | 55.58 6 | E1 | 0.601 | α=0.601 9, α(L)=0.451 6, α(M)=0.1120 16, α(N)=0.0298 4, α(O)=0.00690 10, α(P)=0.001126 16, α(Q)=4.16×10-5 6 | |
| 67.60 | (1-,0-) | 67.60 5 | E1 | 0.359 | α=0.359 5, α(L)=0.269 4, α(M)=0.0666 9, α(N)=0.01774 25, α(O)=0.00414 6, α(P)=0.000692 10, α(Q)=2.76×10-5 4 |
Additional Level Data and Comments:
| E(level) | Jπ(level) | T1/2(level) | Comments |
| 0.0 | (1+) | 2.2 m 2 % β- = 100 | E(level): The Gallagher-Moszkowski rule suggests that the 1+ coupling of the 5/2[642] proton and 7/2[624] neutron states lies lower in energy than the 6+ coupling. If this assumption holds for 242Np then the 2.2-min state can be taken as the g.s. If this assumption is not valid, then the 2.2-min state might be an isomer and the energies of the levels seen in β- decay would need to be increased by the energy of the isomer. |
| 55.58 | (1-,0-) | Jπ(level): From the systematics of Nilsson states, 1979Ha26 proposed π5/2[523],ν7/2[624]1- or π5/2[523],ν5/2[622]0- configurations for the 55.58 and 67.6 levels. Another possible configuration for one of these levels could be π5/2[642],ν7/2[743]; however, systematics of Nilsson orbitals suggests that its energy would be higher than 67.6 keV. | |
| 67.60 | (1-,0-) | Jπ(level): From the systematics of Nilsson states, 1979Ha26 proposed π5/2[523],ν7/2[624]1- or π5/2[523],ν5/2[622]0- configurations for the 55.58 and 67.6 levels. Another possible configuration for one of these levels could be π5/2[642],ν7/2[743]; however, systematics of Nilsson orbitals suggests that its energy would be higher than 67.6 keV. | |
| 0.0+X | (6+) | 5.5 m 1 % β- = 100 | Assignment: 244Pu(30-160 MeV n,p2n); 242Pu(n,p) chem; activity was not observed in 235U(34-MeV α,pxn) (1981Fr07). E(level): Assignment: 244Pu(30-160 MeV n,p2n); 242Pu(n,p) chem; activity was not observed in 235U(34-MeV α,pxn) (1981Fr07). The Gallagher-Moszkowski rule suggests that the 1+ coupling of the 5/2[642] proton and 7/2[624] neutron states lies lower in energy than the 6+ coupling. If this assumption holds for 242Np then the 2.2-min state can be taken as the g.s. If this assumption is not valid, then the 2.2-min state might be an isomer and the energies of the levels seen in β- decay would need to be increased by the energy of the isomer. |
There are no new experimental data on 242Np since the previous evaluation by Y.α. Akovali (2002Ak06). The adopted levels dataset has been updated with Q values from 2021Wa16. The 242U β- decay has been updated with conversion coefficient data from Bricc (2008Ki07) which leads to slightly different β- feedings and logft values
Assignment: 244Pu(200-MeV n,n2p)242U; β- decay; chem (1979Ha26)
Levels: Since the 242U β- decay scheme is tentative, all excited levels proposed from this decay work are adopted as questionable.
Q-value: ΔS(p)=280 (syst,2021Wa16)
Q-value: S(2n)=11040 200, S(2p)=14170 280 (syst) (2021Wa16)