ADOPTED LEVELS for 250Fm
Author: Y. Akovali | Citation: Nucl. Data Sheets 94,131 (2001) | Cutoff date: 1-Aug-2001
Full ENSDF file | Adopted Levels (PDF version)
| Q(β-)=-4.6×103 keV SY | S(n)= 7518 keV 10 | S(p)= 4.39×103 keV SY | Q(α)= 7557 keV 8 | ||
| Reference: 2012WA38 |
| References: | |||
| A | 254No α decay | B | 250Md ε decay |
| E(level) (keV) | XREF | Jπ(level) | T1/2(level) |
| 0.0 | A | 0+ | 30 m 3 % SF = 0.0069 10 % α > 90 % ε < 10 |
| 0.0+X | 1.8 s 1 % ε = ? % IT ≥ 80 % α < 20 % SF ≤ 8.2×10-5 | ||
| 0.0+Y | B | % SF ≤ 100 |
Additional Level Data and Comments:
| E(level) | Jπ(level) | T1/2(level) | Comments |
| 0.0 | 0+ | 30 m 3 % SF = 0.0069 10 % α > 90 % ε < 10 | No ε decay activity was observed: ε/α<0.1 (1957Am47). E(level): No ε decay activity was observed: ε/α<0.1 (1957Am47). |
| 0.0+X | 1.8 s 1 % ε = ? % IT ≥ 80 % α < 20 % SF ≤ 8.2×10-5 | Assignment: 249Cf(α,3n), parent of 30-min 250Fm; 242Pu(12C,X), 243Am(11B,X) and 249Cf(4He,x) cross-bombardment technique; not produced in 243Am(12C) and in 243Am(13C) reactions (1973Gh03). E(level): Assignment: 249Cf(α,3n), parent of 30-min 250Fm; 242Pu(12C,X), 243Am(11B,X) and 249Cf(4He,x) cross-bombardment technique; not produced in 243Am(12C) and in 243Am(13C) reactions (1973Gh03). | |
| 0.0+Y | % SF ≤ 100 | Only the SF decay was observed. No other decay modes have been searched; the level was populated in ε decay of 250Md (1980Ga07). E(level): Only the SF decay was observed. No other decay modes have been searched; the level was populated in ε decay of 250Md (1980Ga07). |
Theoretical studies:
Energies and structures of high-K (K=7- and 8-), low-energy (<2 MeV) states in 250Fm were calculated by 1991So15 in a quasiparticle-phonon nuclear model.
Energies of the lowest K=0+ and K=2+ states and the B(E2; g.s. to 0+), B(E2; g.s. to second 2+) values; energies of the K=0-, 1-, 2- octupole-vibrational states and the B(E3; g.s. to 3-) of these vibrational states were calculated by 1971Ko31 and 1973Iv01.
Properties of the γ-vibrational states were investigated by 1965Be40, and B(E2) values were calculated.
Equilibrium deformations and static electric moment were calculated by 1983Bo15.
For calculations of fission barriers, see, for example, 1976Iw02, 1983Ga05, 1984Ku05, 1989St20, 1992Bh03.
Partial half-life for g.s. SF decay was calculated by 1976Ra02, 1980Lo12, 1983Bo15, 1983Cw01, 1985St22, 1985Lo17, 1988Sa35, 1989St20, 1992Bh03 and 1996Lo08.
The fission barrier and the spontaneous fission half-life of the 1.8-s isomeric state were calculated by 1986Ba43 by considering the possible two quisiparticle states with 8-(n 9/2[734],n 7/2[624]) and 7-(p 7/2[514],p 7/2[633]) configurations for the level.
For a study of heavy-cluster radioactivity and calculations of partial half-lives for such decays, as well as for α and SF decays, see 1988Sa35.
For calculated α decay half-lives, see 1979Po23, 1997Mo25, for example.
Q-value: Note: Current evaluation has used the following Q record -4630 syst 7610 syst 4390 syst 7557 12 1995Au04