ADOPTED LEVELS for 9He
Authors: J.H. Kelley, C.G. Sheu, J.L. Godwin, Et Al. | Citation: Nucl. Physics A745 155 (2004) | Cutoff date: 31-Mar-2004
Full ENSDF file | Adopted Levels (PDF version)
| Q(β-)=1.598×104 keV 5 | S(n)= -1.25×103 keV 5 | ||||
| Reference: 2012WA38 |
| References: | |||
| A | 9Be(11Be,8He+N) | B | 9Be(π-,π+) |
| C | 9Be(14C,14O):1 | D | 9Be(14C,14O):2 |
| E(level) (keV) | XREF | Jπ(level) | T1/2(level) |
| 0.0 | A | 1/2+ | % n = 100 |
| ≈1.1E3 | BCD | 1/2- | 0.10 MeV 6 |
| ≈2.26E3 | B D | 0.7 MeV 2 | |
| 4.20E3 15 ? | D | ||
| ≈5.0E3 | B D | ||
| 8.0E3? | B |
Additional Level Data and Comments:
| E(level) | Jπ(level) | T1/2(level) | Comments |
| 1.1E3 | 1/2- | 0.10 MeV 6 | Decay mode is probably %n=100 based on Q(β-)value; no mode is reported. E(level): Decay mode is probably %n=100 based on Q(β-)value; no mode is reported. Decay mode not specified. |
| 2.26E3 | 0.7 MeV 2 | Decay mode is probably %n=100 based on Q(β-)value; no mode is reported. E(level): Decay mode is probably %n=100 based on Q(β-)value; no mode is reported. Decay mode not specified. | |
| 4.20E3 | Decay mode is probably %n=100 based on Q(β-)value; no mode is reported. E(level): Decay mode is probably %n=100 based on Q(β-)value; no mode is reported. Decay mode not specified. | ||
| 5.0E3 | Decay mode is probably %n=100 based on Q(β-)value; no mode is reported. E(level): Decay mode is probably %n=100 based on Q(β-)value; no mode is reported. Decay mode not specified. | ||
| 8.0E3 | Decay mode is probably %n=100 based on Q(β-)value; no mode is reported. E(level): Decay mode is probably %n=100 based on Q(β-)value; no mode is reported. Decay mode not specified. |
The ground state of 9He is poorly defined. At present the description of the ground state is dominated by observations reported in 9Be(11Be,8He+n) (2001Ch31) which find that 9He is unstable to 8He+n decay by <0.20 MeV; Δ’ M=39.770 MeV 60.
Other reactions reporting states which had been previously identified with the 9He ground state are 9Be(π-,π+) (1987Se05)and 9Be(14O,14C) (1999Bo26). In these previous measurements, it appears that an excited state at 9He*(1.0) [≈1.2 MeV above the 8He+n threshold] had been observed and identified as the ground state.
Q-value: Note: Current evaluation has used the following Q record 14816 60-100 60 2003Au03