17C

β--Decay Evaluated Data



Measurements
1986CU01, 1986HAYX, 1987MIZU: 17C(β-); measured β-decay T1/2.
1986DU07: 17C(β-); measured βγ(t); deduced T1/2. 17N deduced levels, γ-branching.
1988DUZT: 17C(β-n); measured β-delayed xn emission, associated multiplicity, x = 0-4.
1988SA04: 17C; measured β-decay T1/2.
1991RE02: 17C; measured T1/2, neutron emission probability, upper limits. Tof isochronous spectrometer, ion-neutron delayed coincidence.
1993REZX: 17C(β-n); measured β-delayed neutron average energies.
1995SC03: 17C(β-n); measured β-decay curves, neutron spectra; deduced T1/2, log ft. 17N levels deduced branching ratios.
2001AS07, 2002OG02, 2002OG14: 17C(β-); measured β-NMR spectrum from oriented source. 17C deduced ground-state g factor.
Measured half-life for 17C(β-)17N

Recommended value (July, 2015): 193 ± 6 ms  
Summary Table of Uncertainty Analysis:          Table 17C preview (PDF)  
Measured values: 193 ± 6 ms   (1995SC03)
191 ± 12 ms (1994RE1R: see also 174 ± 31 ms in (1991RE02) and 188 ± 10 ms in
the unpublished private communications of (2008REZZ)/(1995REZZ).)
180 ± 31 ms (1988SA04)
202 ± 17 ms (1986CU01)
220 ± 80 ms (1986DU07)
Other Reviews: 191 ± 6 ms   (2015BI05)

Previous Measurements

 

Decay to
17N* (keV)
Jπ Branching Ratio (%) Transition to
17N* (keV)
Eγ (keV) Branching Ratio (%) τm (ps)
(1989WA06) a (1986DU07) (1986DU07) b (1982AJ01) c (1982AJ01) c
1374 3/2-   21 ± 10 0 1374.7 ± 0.5 100 ± 20 100 95 ± 35 fs
1850 1/2+ 40 ± 7 1374   475.6 ± 0.4 22 ± 7 13.5 ± 2.5 41+20-9
0 1848.7 ± 0.6 75 ± 13 86.5 ± 2.5
1907 5/2- 20 ± 8 1374     23.0 ± 2.5 11 ± 2
0 1906.0 ± 0.6 49 ± 13 77.0 ± 2.5
2526 5/2+ 19 ± 9 1907   619.6 ± 0.5 18 ± 8 41.0 ± 2.5 33 ± 4
1850     12.0 ± 1.5
1374       34 ± 23
0     11 ± 1
β-delayed neutron decay of 17C  
(1995SC03)
Enlab (keV) Ex(17N) (keV) d Branching Ratio (%) log ft d
1620 ± 20   7600 ± 20 4.6 ± 0.5 4.58 ± 0.05 e
1930 ± 20   7940 ± 20 2.5 ± 0.3 4.71 ± 0.06 e
2820 ± 30 f 8880 ± 20 2.6 ± 0.3 4.31 ± 0.05  
3730 ± 40 g 9850 ± 20 1.1 ± 0.2 4.18 ± 0.06  
Total Branching Ratio (%) h, i 10.8 ± 2.2    
a) These intensities are relative ones for decay to bound states. To obtain absolute intensities, one would scale by a factor (1 - Pn) where the fraction of decays leading to neutron-unstable states Pn = 0.320 ± 0.027 (1991RE02). This yields 14 ± 7, 27 ± 5, 14 ± 6 and 13 ± 6 for 17N*(1374, 1850, 1907, 2526) respectively.
b) Relative intensities.
c) From (1974RO27, 1974RO28, 1976GU14).
d) Assuming neutron decay to the ground state of 16N; for neutron transitions to excited states in 16N, the log ft values represent an upper limit.
e) The energy separation of the first two neutron groups corresponds to the excitation energy of the second excited state in 16N. For this reason it cannot be excluded that these two groups correspond to the neutron decay of one 17N state to the ground state and second excited state of 16N. In this case the combined branching ratio would correspond to a log ft value of 4.26.
f) Γ = 425 + 150 keV. An unresolved doublet with En = 2.65 and 2.91 MeV cannot be excluded. Under this assumption the neutron group could correspond to a state at Ex = 8.70 MeV which neutron decays to the ground state and the second excited state of 16N.
g) Γ = 435 + 70 keV. An unresolved doublet with En = 3.35 and 3.86 MeV cannot be excluded. Under this assumption the neutron group could correspond to a state at Ex = 9.44 MeV which neutron decays to the ground state and the third excited state of 16N.
h) The errors of the total efficiency (10%), the background subtraction (15%), and the number of observed β-decays (10%) have been added after summing.
i) (1991RE02) measured the β-delayed neutron probability, Pn = 32.0 ± 2.7 % with a polyethylene-moderated 3He neutron counter with a nominaly zero energy threshold. The apparent discrepency between (1991RE02) and (1995SC03) is best understood as evidence for β-feeding of lower energy states that neutron decay with energies below the threshold of (1995SC03).

17B(β-)17C Evaluated Data

17N(β-)17O Evaluated Data

17F(β+)17O Evaluated Data

17Ne(β+)17F Evaluated Data

A = 17 Beta-Decays Diagram

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Last modified: 21 May 2018