ADOPTED LEVELS for 250No
Author: Balraj Singh | Citation: ENSDF | Cutoff date: 15-SEP-2006
Full ENSDF file | Adopted Levels (PDF version)
| S(n)= 8.3×103 keV SY | S(p)= 3.0×103 keV SY | Q(α)= 8.95×103 keV SY | |||
| Reference: 2012WA38 |
| E(level) (keV) | Jπ(level) | T1/2(level) |
| 0 | 0+ | 4.2 µs +12-9 % SF ≈ 100 % α < 2 |
| 1050 Calc. | (6+) | 46 µs +22-14 % SF ≈ 100 |
T1/2(level): From SF decay (2006Pe17) from a total of 158 fission events.
Additional Level Data and Comments:
| E(level) | Jπ(level) | T1/2(level) | Comments |
| 0 | 0+ | 4.2 µs +12-9 % SF ≈ 100 % α < 2 | α decay branching is estimated by the evaluator to be 0.11% by requiring HF(α g.s. to g.s.)=1.0 and r0(246Fm)=1.483, extrapolated from the r0 systematics given in 1998Ak04. Eα(g.s. to g.s.)=8807 (calculated from Q(α)=8850) and Iα(8807α)=80% 5 per 100 α decays are used in calculations. E(level): α decay branching is estimated by the evaluator to be 0.11% by requiring HF(α g.s. to g.s.)=1.0 and r0(246Fm)=1.483, extrapolated from the r0 systematics given in 1998Ak04. Eα(g.s. to g.s.)=8807 (calculated from Q(α)=8850) and Iα(8807α)=80% 5 per 100 α decays are used in calculations. |
| 1050 | (6+) | 46 µs +22-14 % SF ≈ 100 | %α<4.4 or 3.4 (2006Pe17), %α<20 (2003Be18). |
Theoretical studies:
Fission barriers: 2006St04, 1983Cw01, 1992Bh03.
Equilibrium deformations and static electric moment: 1983Bo15.
Collective properties: 2006De33, 2004Gm02, 2002Pr01, 2001Mu10.
2006Pe17: 204Pb(48Ca,2n) E=220 MeV, >99.7% enriched target. Fragment Mass Analyzer at Argonne was used to separate reaction products. The transmitted ions were implanted into a double-sided silicon detector (DSSD). Fission events detected and half-lives measured. Two activities were assigned to 250No
2003Be18: 204Pb(48Ca,2n) E=218-236 MeV. Also 206Pb(48Ca,4n) reaction at 234.5 MeV, VASSILISSA mass separator facility at JINR. Measured two activities: one assigned to 250No and the other to 249No, but with the possibility that both could belong to 250No. 2003Po08 and 2003Ye02 are from the same group.
2001Og08: 204Pb(48Ca,2n) E=213.5-219.4 MeV. Also 206Pb(48Ca,4n) reaction at 213.7-242.5 MeV, gas-filled recoil mass separator facility at JINR. An activity with half-life of 36 μs 11-6 was assigned to 250No.
No evidence was found by 2006Pe17, 2003Be18 and 2001Og08 for the existence of a 0.25S lifetime assigned to 250No by 1975Te01:
The 54-μs activity assigned to 249No by 2003Be18, and also adopted by 2003Au02 and in Nuclear Wallet Cards (2005) is reassigned to 250No by 2006Pe17
1975Te01: 233U(22Ne,5n) E=120 MeV. α 0.25 ms 5 activity assigned to 250No by excluding other possible nobelium elements and the possible SF isomers based on calculated cross-sections and known half-lives. But later work by 2006Pe17 and 2003Be18 did not find any evidence for such an activity belonging to 250No.
Q-value: Note: Current evaluation has used the following Q record 8370 syst 3100 syst 8950 syst 2003Au03
Q-value: Uncertainties: ΔS(n)=400, ΔS(p)=300, ΔQ(α)=200 (2003Au03)