1972AL31: ¹²N; measured βγ-coin; deduced log ft, β-branching.

1974MC11: ¹²N; measured E_β, I_β, βγ-coin; deduced log ft.

1978AL01: ¹²N; measured E_β, I_β, βγ-coin, T_1/2; deduced β-branching, mirror asymmetries, ft.

1981KA31: ¹²N; measured βγ-coin, βγ(t); deduced I_β, log ft.

1985FUZT: ¹²N(β⁺); measured β-asymmetry, NMR; deduced quadrupole coupling constant.

1985IM02: ¹²N(β⁺); measured E_β, I_β.

1985IWZZ: ¹²N(β⁺); measured β-asymmetry; deduced nuclear polarization.

1987KU17: ¹²N(β⁺); measured NMR spectra in GaN; deduced quadrupole effects.

1987MI20: ¹²N(β⁺); measured I_β(θ), aligned nuclei; deduced weak nucleon current parity conservation in isospin space.

1987MI24: ¹²N(β⁺); measured NMR spectra in V crystal; deduced nuclear dipolar broadening.

1988NA09: ¹²N; deduced Gamow-Teller β-decay branching ratio.

1988SHZO: ¹²N(β⁺); measured E_β; deduced shape factor.

1990CA10: ¹²N(β⁺); measured spectral shape factors.

1991LI32: ¹²N; measured β-decay asymmetry.

1992BA11: ¹²; calculated Gamow-Teller β-decay ft-value asymmetry. R-matrix approach.

1992SHZI: ¹²N(β⁺); measured E_β.

1992SOZS: ¹²N(β⁺); measured β(E, θ); deduced polarization correlation coeffecient.

1992TAZP: ¹²N(β⁺); measured T_1/2.

1993MAZU: ¹²N(β⁺); measured β(E, θ) from spin polarized ¹²N implanted in Al; deduced polarization correlation coefficient.

1993OHZX: ¹²N(β⁺); measured NMR. ¹²N deduced quadrupole moment.

1994OHZY: ¹²N(β⁺); measured β-NMR; deduced quadrupole moment.

1996AL23: ¹²N(β⁺); measured β⁺ polarization, polarized source

1997MIZS: ¹²N(β⁺); measured alignment correlation terms in β-ray angular distribution from aligned ¹²N; deduced validity of G-parity conservation law.

1997YAZW: ¹²N(β⁺); measured alignment correlation terms in β-ray angular distribution from aligned ¹²N.

1998MA27: ¹²N(β⁺); measured β-NMR.

1998MI10: ¹²N(β⁺); measured β-NMR. ¹²N deduced quadrupole moment.

1998MI14: ¹²N(β⁺); measured β-ray angular distribution from oriented nuclei; deduced nonzero G-parity violating induced tensor form factor.

1998MI20: ¹²N(β⁺); measured β-NMR. ¹²N deduced quadrupole moment.

1998MIZU: ¹²N(β⁺); measured I_β(θ) from spin aligned nuclei.

1998OHZZ: ¹²N(β⁺); measured E_β; deduced spectral shape factor.

1998SE04: ¹²N(β⁺); measured β⁺ polarization asymmetry from decay of polarized nuclei.

2000MI11: ¹²N(β⁺); measured β angular distributions from aligned nuclei.

2000MIZQ: ¹²N(EC); measured β-NMR; deduced G-parity irregularity.

2001TH18: ¹²N(β⁺); measured positrons longitudinal polarization following decay of polarized source.

2002FY02, 2003FY02: ¹²N(EC); measured β-delayed α-spectra, αα-coin.

2002MI01: ¹²N(β⁺); measured E_β, angular distributions from spin-aligned sources.

2002MI03, 2002MIZZ: ¹²N(β⁺); measured E_β, angular distributions from spin-aligned sources; deduced tensor form factor.

2002MI36: ¹²N(EC); measured E_β, I_β(θ, H, t) from oriented nuclei.

2002MI49: ¹²N(EC); measured E_β, I_β(θ, H, t) from polarized sources; deduced in-medium nucleon mass renormalization, induced tensor form factor.

2003FY04, 2004FY02: ¹²N(EC); measured β-delayed E_α, αα-coin. ¹²C deduced excited states.

2003MI24: ¹²N(β⁺); measured E_β, angular distributions from spin-aligned sources; deduced G-parity irregular induced tensor coefficient.

2004BO43: ¹²N(β⁺); measured β-delayed particle spectra, yields. ¹²C deduced excited states particle-decay features.

2004FY03: ¹²N(β⁺); measured β-delayed E_α, αα-coin. ¹²C deduced levels, J, π, resonance features.

2007PEZY: ¹²N(β⁺); measured branching β-decay ratios.

Measured half-life for ¹²N(β⁺)¹²C

Recommended value:	11.000 ± 0.016 ms	(1978AL01)
Measured values:	11.000 ± 0.016 ms	(1978AL01)
	10.95 ± 0.05 ms	(1963FI05)
	11.0 ± 0.1 ms	(1963PE10)
	11.1 ± 0.2 ms	(1962PO02)
	11.2 ± 0.4 ms	(1959FA03)
	11.43 ± 0.05 ms	(1958VE20)
	12.5 ± 1 ms	(1949AL05)

Previous Measurements

 

Decay to 12C* (MeV)	References	Eβ (MeV)	Branching Ratio (%)	Log ft
0	(1949AL05)	16.6 ± 0.2		4.18 a
	(1958VE20)	16.37 ± 0.06	100	4.17
	(1963GL04, 1963PE10)	16.384 ± 0.015	94.25	4.117 ± 0.002 b
				4.119 ± 0.003 c
	(1978AL01)		94.55 ± 0.60	4.120 ± 0.003 d
4.44	(1958VE20)		15	4.4
	(1963PE10)		2.4 ± 0.2
	(1963WI05)		2.2 ± 0.25 e
	mean		2.3 ± 0.2	5.06 ± 0.04 b
	(1972AL31, 1974MC11) f		2.10 ± 0.16	5.11 ± 0.03 c
	(1978AL01)		2.00 ± 0.10	5.128 ± 0.023 d
			2.02 ± 0.09 g
	(1981KA31)		1.898 ± 0.032	5.149 ± 0.007 d
7.65 h	(1962MA22)		3.0 ± 0.5
	(1963GL04)		2.2 ± 0.6
	mean		2.7 ± 0.4	4.34 ± 0.06 b
10.3 i	(1963GL04)		0.85 ± 0.6
	(1963WI05)		0.44 ± 0.15
	mean		0.46 ± 0.15	4.36 ± 0.17 b
12.71 j	(1967AL03)		0.29 ± 0.13	3.55 ± 0.16 b
			0.31 ± 0.12 k	3.52 ± 0.14 k
15.11	(1967AL03)		(4.4 ± 1.5) x 10-3	3.30 ± 0.13 b

a) (FE51B); see also (KI52).

b) Based on Qm and T1/2 = 10.97 ± 0.04 ms: see (BA66A).

c) Based on Qm and T1/2 = 10.97 ± 0.04 ms: see (1974MC11 and BA66A).

d) Based on Qm and T1/2 = 11.000 ± 0.016 ms. See aldo (1976CA29 and RA78F).

e) 1.72 times 12B value.

f) Based on adopted branching ratio 1.29 ± 0.05 % for 11B(β-) → 12C*(4.4) and "best" value of the 12N/12B ratio for this decay, R = 1.63 ± 0.11.

g) Adopted. See also reference 7 in (1977KA24).

h) See also (1963WI05).

i) (1966SC23).

j) See also (1963GL04, 1963WI05, 1966SC23).

k) From R.W. Kavanagh's comments to Fay Ajzenberg-Selove (1990AJ01).

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¹²B(β^-)¹²C Evaluated Data

A = 12 Beta-Decays Diagram

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Last modified: 08 July 2009