Authors: J.H. Kelley, C.G. Sheu |  Citation: ENSDF |  Cutoff date: 16-Jan-2016 

 Full ENSDF file | Adopted Levels (PDF version) 

Q(β-)=2.693×104 keV 18S(n)= -5 keV 5
Reference: 2012WA38

  A  9Be(19C,18B) 

General Comments:

The particle instability of 18B was established with the failure to observe 18B nuclei in the fragmentation products of 44 MeV/nucleon 40Ar ions on a Ta target (1985La03,1986Po13), or in the fragmentation products of 12 MeV/nucleon 56Fe ions on a Be target (1984Mu27). Its neutron separation energy is well known as S(n)<10 keV, hence the uncertainty in its mass excess (ΔM= 51850 keV 170) is mainly determined by uncertainty in the 17B mass (ΔM=43770 keV 170) (2012Wa38).

Theoretical Predictions:

The s-wave neutron emission, observed in (2010Sp02), is consistent with a Jπ=2- spin assignment for 18B. The shell model calculations of (1992Wa22) predict Jπ=2- for the ground state with the first three excited states at 0.45, 0.52, 0.839 MeV with Jπ=4-, 2-, 3-; an update of this calculation is given in (2010Sp02). On the other hand, (1985Po10) predicted the 18B ground state to have Jπ=4- and to have excited states at 0.62, 0.86, and 1.59 MeV with Jπ=1-, 2- and 2- (1985Po10). As discussed in (2010Sp02), the inability to definitively identify the 18B and 17B states participating in the observed decay leaves some uncertainty in the Jπ assignment.

See other general predictions in (1997Ba54,2004La24,2006Ko02,2012Yu07)

XREFJπ(level) T1/2(level)
  0A (2-) % n = 100

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