β--Decay Evaluated Data

1951GA30: 9Li; measured T1/2.
1952HO25: 9Li; measured T1/2.
1952SH44: 9Li; measured T1/2.
1961HI01: 9Li; measured not abstracted; deduced nuclear properties.
1963AL18: 9Li; measured not abstracted; deduced nuclear properties.
1965DO13: 9Li; measured T1/2.
1965SC17: 9Li; measured not abstracted; deduced nuclear properties.
1969MA11: 9Li; measured En, In(t), βγ-, γγ-coin; deduced log ft.
1970CH07: 9Li; measured T1/2, Eβ, βn-coin, E(delayed n), E(delayed α); deduced log ft, Iβ. 9Be deduced levls, J, π, Γ, Γn.
1970CHZU: 9Li; measured T1/2, delayed-n, delayed-α spectra; deduced log ft. 9Be deduced levels, level-width.
1974RO31: 9Li; measured Eγ, Iγ, T1/2, delayed neutrons, βγ-coin, Eβ.
1976AL02: 9Li; measured Eγ, Iγ, γ(t), T1/2, delayed neutrons log ft.
1976FI03: 9Li; measured T1/2, delayed γ, delayed neutrons.
1979DEYX: 9Li; measured β-delayed Eα, Iα.
1979GA20: 9Li; measured β-decay T1/2.
1981BJ01: 9Li; measured βn-coin.
1981LA11: 9Li; measured β-delayed Eα, βα-coin. 9Li deduced single neutron emission probability, β-delayed I(n). 9Be levels deduced anti-analog character.
1983CO11: 9Li(β-); measured β asymmetry, NMR, oriented nuclei; deduced μ, quadrupole moment relative to 7Li.
1986CU01, 1986HAYX: 9Li(β-); measured β-decay T1/2.
1986RO27: 9Li(β-); measured T1/2.
1987AR22: 9Li(β-); measured β-asymmetry, NMR, hfs. 9Li deduced μ.
1987ARZN: 9Li; measured β-decay asymmetry. 9Li deduced quadrupole moment relative to 8Li.
1987TE04: 9Li(β-), (n); measured neutron spectrum.
1988AR17: 9Li(β-); measured β asymmetry, β-NMR spectra; 9Li level deduced nuclear quadrupole moment.
1988SA04: 9Li; measured β-decay T1/2.
1990ABZR: 9Li(β-); measured T1/2.
1990NY01: 9Li(β-); measured β-delayed neutron, alpha spectra; deduced log ft. 9Be levels deduced branching ratios, B(GT). R-matrix analysis.
1991BO31: 9Li; measured continuum particle spectra following β-decay; deduced log ft, Gamow-Teller transition strength, level width, di-neutron, neutron halo roles.
1991LUZZ: 9Li(β-); measured T1/2.
1992LI24: 9Li(β-); measured β NMR asymmetry; deduced quadrupole moment raio.
1992TE03: 9Li; measured Iβ, T1/2, neutron emission probabilities.
1993NE08: 9Li(β-); measured β-NMR asymmetry.
1994AR19: 9Li(β-); measured β-NMR, polarized source; deduced quadrupole moment ratio.
1994JO04: 9Li(β-); compiled, reviewed β-decay data; deduced halo role.
1994RE1R, 1991RE02: : 9Li(β-n); measured T1/2, neutron emission probabilities.
1997SO34: 9Li(β-n); measured decay products, En, In; deduced neutron emission probabilities.
1999BE53: 9Li; measured T1/2.
2000KOZJ: 9Li(β-); measured Eβ; deduced Qβ, T1/2. ISOL.
2003PR11: 9Li(β-); measured β-delayed Eα, αα-coin. 9Be deduced level J, π, β-branching strengths. A=9; deduced β-decay asymmetry in mirror transitions.
2004BO22: 9Li(β-); analyzed β-delayed Eα, Ep, En, angular correlations. 9Be deduced level energies, widths, decay branching ratios.
2004MUZY: 9Li(β-); measured β-delayed Eγ, Iγ, βγ-coin. 9Be deduced transitions, branching ratio limits.
2004PR11: 9Li(β-); measured Eα, αα-coin following daughter nucleus decay; deduced Gamow-Teller transition strength. 9Be levels deduced particle decay branching ratios.
2005BO45: 9Li(β-); measured β-asymmetries, β-NMR spectra from polarized sources. 9Li deduced quadrupole moments. 9Li deduced μ.
2005MI30: 9Li(β-); analyzed transitions B(GT), symmetry effects.
2005MU26: 9Li(β-); measured Eγ, βγ-coin. 9Be levels deduced decay widths.
2005PR11: 9Li(β-); measured β-delayed Eα, αα-coin; deduced β-decay branching ratios. 9Be deduced levels, J, π, resonance states.
2006BA47: 9Li(β-); analyzed β-decay data; deduced inconsistencies with previous results.
2006BO32: 9Li(β-); measured Eα, En following daughter nucleus decay. 9Be deduced levels, J, π, widths, decay branching ratios.
2007MA91: 9Li(β-); measured delayed Eα, Iα, angular distributions. 9Be deduced decay channels.
2007MAZY: 9Li(β-); measured β-delayed Eα. 9Be; measured breakup of the 2.43 state.
2008MAZY: 9Li(β-); measured β-delayed Eα, Iα, αα-coin. 9Be; deduced levels, partial decay branches.
2008RIZX: 9Li(β-); measured β-delayed neutron decay.
2009GE04: measured β-delayed neutron yield, excitation function.
2011VO08, 2014VO01: 9Li; measured β-NQR spectra; deduced electric quadrupole moments.
2015HI02: 9Li(β-), (β-n); measured Eβ, E(n) by TOF, I(n), nβ-coin, β-decay asymmetry spectrum. 9Be; deduced levels, J, π, β-delayed neutron transitions, asymmetry parameter for each β transition, Iβ, log ft; deduced neutron branching ratios from states in 9Be through n+8Be and α+5He channels.
2015MAZV: 9Li(β-); measured spin-polarized 9Li β-decay, nβ-coin; deduced J, π, β-decay asymmetry, 9Li decay scheme.

Measured half-life for 9Li(β-)9B

Recommended value (August, 2015): 177.7 ± 0.6 ms (Weighted Average)
Summary Table of Uncertainty Analysis:     Table 09Li preview (PDF)  
Measured values: 178 ± 3 ms (1999BE53)
181.8 ± 0.4 ms (1997SO34) (Excluded: insufficient experimental details)
178 ± 1 ms (1992TE03)
178.1 ± 0.6 ms (1994RE1R: see also 175.5 ± 7.6 ms in (1991RE02) and 178.1 ± 0.6 ms
in the unpublished private communications of (2008REZZ)/(1995REZZ).)
  167 ± 20 ms (1988SA04)
  173 ± 14 ms (1986CU01)
178.3 ± 0.4 ms (1976AL02)
  179 ± 16 ms (1976FI03)
175 ± 1 ms (1973AU1A, 1974RO31)
177 ± 3 ms (1970CH1T, 1970CH07)
176 ± 1 ms (1965DO13)
  172 ± 25 ms (1965SC17)
  190 ± 30 ms (1963AL18)
  170 ± 10 ms (1961HI01)
170 ± 5 ms (1952HO25)
  190 ± 50 ms (1952SH44)
168 ± 4 ms (1951GA30)
Other Reviews: 178.2 ± 0.4 ms (2015BI05)

Previous Measurements


Decay to
9Be* (MeV)
Jπ Branching Ratio (%) Log ft B(GT) d
(1963AL18) (1970CH1T, 1970CH07) (1981LA11) (1993CH06) a (1963AL18) (1969MA11) (1970CH1T, 1970CH07) b c
0 3/2- 25 ± 15 65.0+2.7-2.4 50.5 ± 5 e 49.2 ± 0.9 f 5.5 ± 0.2   5.12+0.01-0.02 5.20+0.01-0.02 5.31 0.0292 ± 0.0009  
2.43 5/2- 75 ± 15 32.0+2.7-3.7 g 34 ± 4 29.7 ± 3.0 h 4.7 ± 0.2 5.2 ± 0.2 5.00+0.04-0.28 5.10+0.04-0.05 5.07 0.046 ± 0.005  
  2.78 i 1/2-   3.0+2.7-0.3 g 10 ± 2 15.8 ± 3.0 h     5.97+0.05-0.28 6.06+0.05-0.28 5.54 0.011 ± 0.005 j
7.94 (5/2-) a,k       1.5 ± 0.5 < 2% l         5.04 0.048 ± 0.018 j
11.28   (7/2-) m,n          4 ± 0.5 1.1 ± 0.2 l           2.87 o 1.4 ± 0.5 j
11.81     5/2- p     < 0.1 2.7 ± 0.2 l         > 4.0       8.9 ± 1.9 j
a) Based on Tables II and III of (1993CH06) taking into account the different value for Pn.
b) M.J. Martin, Nucl. Data Project, private communication to Fay Ajzenberg-Selove (1979AJ01).
c) M.J. Martin, private communication to Fay Ajzenberg-Selove (1984AJ01).
d) B(GT) includes the factor (gA/gB)2. The empirical quenching found by (1993CH06) gives (gA/gB)2eff = 1.14 and permits a comparison with p-shell calculations.
e) Pn = (50 ± 4)% (1981BJ01); Pn = (49.5 ± 5)% (1981LA11).
f) Obtained using Pn = (50.8 ± 0.9)%, which is the average of (50.0 ± 1.8)%(1991RE02)and (51.0 ± 1.0)% (1992TE03).
g) See also (1973RO2F).
h) (1990NY01).
i) 2.78 ± 0.12 MeV, Γc.m. = 1.10 ± 0.12 MeV; θ2p = 0.48 ± 0.06 (1970CH07).
j) For decay to an unbound level B(GT) is not well defined. (1990NY01) deduce B(GT) taking into account the variation of the statistical factor over the width of the final states and the considerable error in this procedure is reflected in the errors tabulated.
k) (1981LA11) suggest (1/2-) on the basis of the branching ratios.
l) From (1990NY01).
m) A 7/2- level is known at this energy. A strong β transition implies Jπ = 1/2-, 3/2-, or 5/2-, with 5/2- unlikely on theoretical grounds given that the 11.8 MeV state has been assigned 5/2-.
n) (1981LA11) suggest (3/2-) on the basis of the branching ratios.
o) (1981LA11) suggest that the very low log ft value implies that 9Be*(11.28) is the anti-analog of 9Li(0).
p) (2003PR11) find that the decay mainly populates the 11.8 MeV state, determine a spin of 5/2-, and extract a B(GT) value of 8.5 ± 1.5.

9C(β+)9B Evaluated Data

A = 9 Beta-Decays Diagram

Back to Top

Back to Ground-State Decays Data Main Page

Back to Datacomp Home Page

Last modified: 28 June 2021