
^{15}N (1959AJ76)(See the Energy Level Diagram for ^{15}N) GENERAL: See also Table 15.2 [Table of Energy Levels] (in PDF or PS). Theory: See (1956KA1C, 1957FE1A, 1957HA1E, 1957PE1D, 1958FR1C).
See (1957NO17).
Reported resonances are listed in Table 15.3 [Resonances in ^{11}B + α] (in PDF or PS) (1954BE08, 1954TR09, 1955SH46, 1956BO61, 1958HA1B: see also (1950HO80)). Some absolute cross sections are given by (1956BO61). See also ^{14}N.
Reported resonances are listed in Table 15.3 [Resonances in ^{11}B + α] (in PDF or PS) (1955SH46, 1958LE23, 1959LE28). Angular distributions of the ground state protons have been measured at 150 energies in the range E_{α} = 2 to 4 MeV. The assignment J = 5/2^{+} to ^{15}N*(12.50) agrees with an independent determination in ^{14}N(n, n)^{14}N (1958LE23). Partial widths for several resonances are listed by (1959LE28). See also ^{14}C.
See (1951PO1A).
Proton groups have been observed corresponding to the ground state of ^{15}N and to ^{15}N*(5.4, 6.5) and to other unresolved excited states up to E_{x} ≈ 13.5 MeV (1951BU1D, 1951BU1E, 1957SH1C). Angular distributions have been studied at E_{α} = 30.5 MeV (1957HU1E) and 41.5 MeV (1957SH1C). They all show strong anisotropic structure typical of direct interaction. The ground state angular distribution is qualitatively similar to that of the inverse reaction. An excellent fit is obtained to the data > 30° under the assumption l (triton) = 1, R = 5.10 × 10^{13} cm (1957SH1B, 1957SH1C: see also (1957BU52)).
Observed resonances are displayed in Table 15.4 [Resonances in ^{13}C + d] (in PDF or PS) (1950RI57, 1955MA76). Absolute cross sections are given by (1955MA76). See also ^{14}N and (1957JA37).
Observed resonances are displayed in Table 15.4 [Resonances in ^{13}C + d] (in PDF or PS) (1941BE1A, 1950CU13, 1953KO42, 1956MA46). Angular distributions have been measured at a number of energies in the range E_{d} = 0.3 to 2.8 MeV (1953KO42, 1956KO26, 1956MA46, 1956VA17). At most energies some stripping contribution is observed, although compound nucleus formation appears to be quite important for E_{d} < 3 MeV (1956MA46). There is some disagreement on absolute cross sections; see (1953KO42, 1956MA46, 1956VA17, 1957HO63). See also ^{14}C.
Observed resonances are listed in Table 15.4 [Resonances in ^{13}C + d] (in PDF or PS). Angular distributions and absolute cross sections are reported (1956MA35). See also ^{12}C.
Observed resonances are listed in Table 15.4 [Resonances in ^{13}C + d] (in PDF or PS). Angular distributions and absolute cross sections are reported. Analysis of the narrow E_{α} = 2.2 MeV resonance suggests that it is formed by l_{d} = 3 or 4 (1956MA35). See also ^{11}B.
Not reported.
Proton groups have been observed corresponding to the ground state of ^{15}N and to the levels at 5.3 MeV (unresolved) and 6.3 MeV; E(^{3}He) to 4.5 MeV. Angular distributions show strong forward and backward peaking, roughly symmetric about 90°, and may indicate either compound nucleus formation or exchange stripping (1956SC01, 1957IL01, 1957JO1B). See also (1957BR18) and ^{16}O.
Not observed.
Resonances for capture γradiation are listed in Tables 15.5 [LowEnergy ^{14}C(p, γ)^{15}N Resonances] (in PDF or PS) and 15.6 [Resonances in ^{14}C(p, γ_{0})^{15}N and ^{14}C(p, n)^{14}N] (in PDF or PS). The energies of the first four resonances (Table 15.5 [LowEnergy ^{14}C(p, γ)^{15}N Resonances] (in PDF or PS)) agree well with level energies derived from ^{14}N(d, p)^{15}N (1958HE48, 1959HE1D); corresponding values given by (1955BA44) are 8 to 10 keV higher. Quoted limits on l_{p} in Table 15.5 [LowEnergy ^{14}C(p, γ)^{15}N Resonances] (in PDF or PS) are based on estimates of Γ_{p}. The assignment 3/2^{+} to ^{15}N*(10.71) is based on ^{14}C(p, p)^{14}C (1958HE48, 1959HE1D); the assignment 3/2^{} gives a more satisfactory account of the p, γ_{0} angular distribution both for this level and for ^{15}N*(10.81) (1955BA44); J = 3/2^{+} is, however, not excluded for either (1957BA18). Combination of ^{15}N*(10.81) and ^{15}N*(9.84) permits a good account of the low energy (n, n) and (n, γ) cross sections (1959HE1D). The thermal (n, p) cross section can be ascribed to the E_{p} = 1.5 MeV resonance (^{15}N*(11.61)) (1955BA44: see also ^{14}N(n, γ)^{15}N). Strong interference effects in the (p, γ) yield curve indicate that the E_{p} = 1.31 and 1.50 MeV states have the same J^{π} (the former is given as 1/2^{+} from ^{14}N(n, n)^{14}N) and that the E_{p} = 1.16 MeV state has opposite (odd) parity: J = 1/2^{}, 3/2^{}; J = 1/2^{} is favored by σ(n, n). The E_{p} = 1.66 MeV state has even parity. Assignments for these four levels indicated in Table 15.6 [Resonances in ^{14}C(p, γ_{0})^{15}N and ^{14}C(p, n)^{14}N] (in PDF or PS) are consistent with the ^{14}C(p, n)^{14}N results (1955BA44: see also (1953KA1A)). The state at E_{p} = 1.50 MeV probably has T = 3/2 and corresponds to ^{15}C_{g.s.} (1955BA44, 1956BA16: see ^{14}C(p, n)^{14}N). See also (1954SP1B, 1956FE1C).
Elastic scattering has been studied for E_{p} = 340 to 690 keV. At the E_{p} = 527 keV resonance (see Table 15.5 [LowEnergy ^{14}C(p, γ)^{15}N Resonances] (in PDF or PS)), the scattering is consistent with dwave formation of a J = 3/2^{+} state, Γ_{p} = 0.2 keV. No anomalies are observed at E_{p} = 351 or 635 keV (1958HE48, 1959HE1D).
Resonances reported by (1951RO16, 1953KA1A, 1954BA1C, 1955BA44, 1956SA06) are listed in Table 15.6 [Resonances in ^{14}C(p, γ_{0})^{15}N and ^{14}C(p, n)^{14}N] (in PDF or PS): see also (1959GI47). Neutron distributions are essentially isotropic at the E_{p} = 1.16, 1.31 and 1.50 MeV resonances and agree with the assignments derived from ^{14}C(p, γ)^{15}N and ^{14}N(n, n)^{14}N; the distribution at E_{p} = 1.67 MeV favors J = 3/2. At E_{p} = 1.79 MeV, the distributions favor 5/2^{}, but 3/2^{} is not excluded (1955BA44: see also (1953KA1A)); a computation of the cross section favors J = 3/2 (1956SA06). At E_{p} = 1.88 MeV, the angular distribution is consistent with the J = 1/2^{} assignment from ^{14}N(n, n)^{14}N and at E_{p} = 2.02 MeV the appearance of a P_{4}(cos θ) term supports the assignment J = 5/2, excluding J = 5/2^{+} (1955BA44: compare Table 15.7 [Gamma Radiation from ^{14}N(n, γ)^{15}N] (in PDF or PS)). Parities of this and the next two states disagree with ^{14}N(n, n)^{14}N results. The E_{p} = 2.27 MeV state has J = 3/2 or 5/2; the σ_{nn} clearly indicates the latter (1955BA44, 1956SA06). For ^{15}N*(11.61) (E_{p} = 1.50 MeV), the proton reduced width indicates a singleparticle level, while the neutron reduced width is only 10^{3}. This behavior is taken to indicate that the level has T = 3/2 and corresponds to ^{15}C_{g.s.}; the predicted energy from M(^{15}C) is ^{15}N*(11.7 to 11.9 MeV) (1955BA44, 1956BA16).
Neutron groups have been observed corresponding to levels in ^{15}N at 5.34, 6.32, and 7.46 MeV (1950HU72). See also (1956FR1A; theor.).
Not reported.
Not reported.
See ^{15}C.
The thermal cross section is 80 ± 20 mb (1957BA18). Observed γrays are given in Table 15.7 [Gamma Radiation from ^{14}N(n, γ)^{15}N] (in PDF or PS) together with the ^{15}N levels with which they are presumed to be associated. The decay scheme is in good accord with that derived from ^{14}N(d, p)^{15}N (1957BA18). It does not appear that any of the known levels in this region can account for the large thermal cross section. The J = 1/2^{+}; T = 3/2 level at ^{15}N*(11.61) gives the same capture radiation spectrum and accounts very well for the thermal ^{14}N(n, p)^{14}C cross section, but contributes only 0.4 mb to σ_{nγ}. The required level is presumably to be found below the neutron threshold, ^{15}N*(10.2 to 10.7 MeV), and should have a large neutron and a small proton width, =1/2^{+} or 3/2^{+}, and Γ_{γ0} = 1 eV (1955BA44): compare ^{14}C(p, γ) (1959HE1D). See also (1958RA13).
The coherent scattering cross section is 11.0 ± 0.5 b; the total scattering cross section is 11.4 ± 0.5 b (bound atoms, epithermal neutrons: see (1958HU18)). The large thermal scattering reflects a nearby bound level (1949ME51). The approximate equality of the two values indicates that the scattering has little spin dependence (1955FO27). See (1959HE1D). Resonances in the range E_{n} = 0.4 to 2.3 MeV are listed in Table 15.8 [Resonances in ^{14}N + n] (in PDF or PS) (1951JO23, 1952HI12, 1955FO27, 1955HU1B, 1957HU1D, 1958HU18). Angular distributions at and between these resonances have been studied by (1950BA1C, 1955FO27). The potential swave phase shift approximately fits hardsphere scattering (R = 3.7 × 10^{13} cm) for E_{n} < 1.3 MeV: from 1.3 to 1.7 MeV, an abrupt increase (negative) appears, which may be associated with a shape resonance. The pwave phase shift is somewhat smaller than the hardsphere value; the dwave shift is < 3° (1955FO27: E_{n} < 2.0 MeV). The narrow E_{n} = 430 keV resonance is formed by l_{n} ≥ 1; the proton width is very small, and the level has not been detected in ^{14}C + p. The E_{n} = 495 keV resonance appears strongly in ^{14}N(n, p)^{14}C and ^{14}C(p, n)^{14}N, but not in elastic scattering. The two resonances at E_{n} = 639 and 998 keV are swave, assigned J = 1/2^{+} and 3/2^{+}, respectively from σ_{max}  σ_{min} (1951JO23, 1952HI12). According to (1956FE1C) an additional broad J = 1/2^{+} level is located in this region (^{14}C(p, n)^{14}N; E_{p} = 1.5 MeV: ^{14}N* = 11.61 MeV), presumably the first T = 3/2 state. This level has not appeared in ^{14}N(n, n)^{14}N; see e.g. (1955FO27). The E_{n} = 1120 keV resonance is given as J = 3/2 or 5/2 from cross sections; the angular distributions favor 3/2^{} (1955FO27). The narrow 1188 keV resonance does not appear in (^{14}C + p) (1956SA06). Aside from the J = 1/2^{} resonance at E_{n} = 1211 keV, the remaining J^{π} assignments disagree with those derived from ^{14}C + p (compare (1955FO27) and (1955BA44)). For the E_{n} = 2250 keV resonance, (1955FO27) find J = 3/2^{}, while (1953ME1B) report J = 1/2^{}. From E_{n} = 1.8 to 4.0 MeV, there is evidence for considerable structure in the cross section curve, but little agreement as to the exact location of the levels involved. (1953ME1B) list 14 maxima in the total cross section for E_{n} = 1.9 to 3.6 MeV. Angular distributions have been studied by (1954HU1B) for energies between 3.2 and 3.9 MeV. The observed distributions can be accounted for by seven levels in the range 2.5 to 4.4 MeV with J = 3/2^{+} to 7/2^{+} (1954SP1C, 1954SP1D). See also (1955AJ61, 1956BE98, 1956FL1B, 1957HU1D).
At E_{n} = 14.3 MeV, the cross section is 4.5 ± 0.8 mb (1955HU1B), 19 ± 10 mb (1958AS63), 8.5 mb (1958RA18). See also (1955SM1B).
The thermal cross section is 1.75 ± 0.05 b (1958HU18). A major portion of this cross section can be ascribed to ^{15}N*(11.61) (1955BA44). Resonances reported by (1950JO57) occur at E_{n} = 495, 640, (993), and 1415 keV; parameters are listed in Table 15.8 [Resonances in ^{14}N + n] (in PDF or PS) (1955HU1B, 1958HU18). Many additional levels have been reported through analysis of particle groups induced by continuous neutron spectra: see (1952AJ38, 1953GI1B, 1957BE71).
(1950JO57) report resonances at E_{p} = 1415 and 1800 keV: see Table 15.8 [Resonances in ^{14}N + n] (in PDF or PS) (1955HU1B). See also ^{14}N(n, p)^{14}C above.
See (1952LI24, 1957CA07, 1957ZA1A), ^{14}N and ^{13}C.
For reaction (a), see (1953FI28). For reaction (b), see (1956FR18).
Proton groups corresponding to levels of ^{15}N are listed in Table 15.9 [^{15}N Levels from ^{14}N(d, p)^{15}N] (in PDF or PS). The J^{π} assignments are based on stripping analysis of angular distributions (1950MA65, 1952GI01, 1954SP01, 1955SH28, 1956DO41, 1956GR37, 1957WA01). A detailed comparison of the experimental observations with shellmodel calculations is made by (1957HA1E: see also (1957WA01)). Angular distributions have also been studied by (1954EB02, 1954JO1F, 1956VA17, 1958BO18). The ratio of the reduced widths of the ground states of ^{15}N and ^{15}O is 1.71 (1956CA1D: E_{d} = 9 MeV). Observed gamma rays are listed in Table 15.10 [Gamma Rays from ^{14}N(d, p)^{15}N] (in PDF or PS) (1955BE81, 1958RA13). The observation of a 10.81 MeV γray indicates a small proton width for the ^{15}N level; it is suggested that this level may account for the large (n, γ) cross section (1958RA13). According to (1955BA44, 1958HE48), however, the γspectra are quite different: see Tables 15.5 [LowEnergy ^{14}C(p, γ)^{15}N Resonances] (in PDF or PS) and 15.7 (in PDF or PS). A 1.88 MeV γray is reported by (1954TH1B), attributed to ^{15}N*(7.16 → 5.2). A pγ correlation experiment suggests that the 5.3 MeV radiation is dipole (1954ST1C). The relative intensities of the 7.31 MeV γray and of the ^{15}O 6.81 MeV radiation have been determined at several energies by (1955BE1G). See (1956EL1B, 1956FR1A, 1957HA1E, 1957SH1B; theor.).
See (1952CU1B).
Not reported.
With bremsstrahlung of E_{max} = 18.7 and 24.6 MeV, photoprotons corresponding to the ground state and excited states of ^{14}C are observed. Peaks in the yield appear at E_{γ} = 11.6, ≈ 15, ≈ 18.6 MeV, in addition to the giant resonance at ≈ 20 MeV. The first peak corresponds to excitation of ^{15}N* (J = 1/2^{+}; T = 3/2): the angular distribution is consistent with isotropic emission. At 15 MeV, the distribution indicates dipole absorption, while the giant resonance shows a predominantly sin^{2}θ distribution (1958RH1A, 1958RH30).
See ^{15}O.
Transitions have been observed to the 5.3 and 6.3 MeV levels of ^{15}N (1955ST1D, 1957SV1A). See also ^{16}O.
See (1952LI24).
At E_{p} = 185 MeV, the summed proton spectrum shows two peaks, corresponding to ejection of p_{1/2} and p_{3/2} protons with binding energies of ≈ 12 and ≈ 19 MeV, respectively. The separation is consistent with the interpretation of ^{15}N*(6.3) as a state with a hole in the p_{3/2} shell (1958MA1B, 1958TY49).
Not reported.
See (1956BA1E, 1956JA31, 1956MA09).
See (1952AJ38, 1955RI1A) and ^{19}F.
