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12N (1980AJ01)
(See Energy Level Diagrams for 12N)
GENERAL: See also (1975AJ02) and Table 12.21 [Table of Energy Levels] (in PDF or PS).
Model calculations: (1976IR1B).
Pion reactions (See also reaction 2.): (1975NA16, 1976NA16, 1978BU1J, 1978EP01, 1978NA1N, 1979BO23, 1979BOZW, 1979DI1A, 1979EP1B, 1979NA1Q, 1979WI1A).
Other topics: (1975HU14, 1976AB04, 1976BE1K, 1976IR1B, 1977SI1D, 1978SE1B, 1979WI1A).
Ground state of 12N: (1974SHYR, 1975BE31, 1977YO1D, 1978LEZA).
The value of | eqQ/h| for 12N in Hg is 59.3 ± 3.3 kHz (1977TA04).
| 1. 12N(β+)12C | Qm = 17.338 |
The half-life of 12N is 11.000 ± 0.016 msec (1978AL01): 12N decays to 12C*(0, 4.44, 7.65, 10.3, 12.71, 15.11): see Table 12.20 (in PDF or PS).
| 2. 10B(3He, n)12N | Qm = 1.574 |
Observed neutron groups are displayed in Table 12.22 (in PDF or PS). Angular distributions have been studied at E(3He) = 2.5 to 13 MeV: see (1975AJ02).
| 3. 12C(γ, π-)12N | Qm = -156.905 |
π- electroproduction has been studied at 90° for Eπ ≈ 17 and 29 MeV (1979PA06) (The total cross section (measured from threshold to Eγ = 360 MeV) peaks at Eπ- ≈ 40 MeV [σ ≈ 8 μb] and then gradually decreases (1979BO23).). See also (1976BE39, 1979BO1Y, 1979BOZW) and the "GENERAL" section here.
| 4. 12C(p, n)12N | Qm = -18.120 |
At Ep = 50 MeV neutron groups are reported to 12N*(0, 1.0, 3.7, 4.2, 5.3, 7.5) (1970CL01). Angular distributions have been reported at Ep = 30.5 and 49.5 (1970CL01), 61.9 (1977GOZY) and 144 MeV (1977MO1M, 1979MOZY). At Ep = 62 and 135 MeV, the M1 strength appears to be concentrated in the ground state group (1977BA2X). At Ep = 647 and 800 MeV, the spectra show a narrow high energy peak and a broad bump at lower energies associated with pion production (1976CA17). See also (1976ANZQ), (1976NO1E, 1976SL2A) and (1978GO1E; applications).
| 5. 12C(3He, t)12N | Qm = -17.357 |
Triton groups observed at E(3He) = 44 to 49.8 MeV are displayed in Table 12.23 (in PDF or PS). Angular distributions of inelastically scattered 3He to 12C*(15.11, 16.11, 16.58, 19.57) have been compared with those of tritons to 12N*(0, 0.96, 1.19, 4.25). When the 3He cross sections are corrected for phase-space and isospin factors, the angular distributions are closely similar (to within 10%) to those for the triton groups, strongly suggesting isobaric analogs (1969BA06). At E(3He) = 44 MeV the distributions to 12N*(2.42) and to 12C*(17.77) are found to be similar. This, coupled with the strength of the group to 12N*(2.42) in the 14N(p, t) reaction, suggests that 12N*(2.42) and 12C*(17.77) are analog states and therefore that 12N*(2.42) has Jπ = 0+ (1976CE02). See also (1976MA15). Angular distributions have also been studied at E(3He) = 217 MeV (1974WI16, 1976WI05).
At E(3He) = 49.3 MeV (1976MA15) report no evidence for a state at Ex = 1.72 MeV. A 1- state exists in 12B at Ex = 2.62 MeV. The missing analog state in 12N would have a width > 1 MeV. 12N*(4.15, 5.23), observed in this reaction, occur at lower energies and are broader than 12N*(4.25, 5.32) reported in 10B(3He, n); and 12N*(6.10, 7.13) observed here are not reported in 10B(3He, n). It is suggested that the selectivity is greater in the latter reaction and that the triton groups go to unresolved states. At higher Ex it should be pointed out that many more states are observed in 12B than in 12N: with the possible exception of the relatively narrow states 12N*(9.42, 9.90), the other reported groups with Ex > 6 MeV may thus be due to unresolved groups (1976MA15). See also (1975GO1L, 1978TA1M).
| 6. 12C(14N, 14C)12N | Qm = -17.494 |
See (1975NA11).
| 7. 14N(p, t)12N | Qm = -22.135 |
At Ep = 51.9 MeV angular distributions of the tritons to 12N*(0, 0.96) and of the
3He ions to the analog T = 1 states [12C*(15.11, 16.11)] have been measured (1976YO03). At Ep = 52.5 MeV the angular
distribution to 12N*(2.42) has been studied: see reaction 5 (1976CE02). The atomic mass excess of 12N
derived from this reaction is 17338 ± 1 keV (1976NO1J): it is adopted by (1977WA08).