Recent Articles

Heavy-ion distorted-wave Born-approximation recoil to second order in a Taylor series

A. J. Baltz

Phys. Rev. C 13, 668 (1976) - Published 1 February, 1976

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The perturbative approach for rapid calculation of recoil corrections to the heavy-ion distorted-wave Born approximation has been extended to second order without further approximation. The resulting calculational scheme turns out to be so well converged as to be essentially exact finite range for single nucleon transfer at energies not too far above the Coulomb barrier.

NUCLEAR REACTIONS Proper second order recoil DWBA. ${}^{48}{Ca}$ ( ${}^{14}N$ , ${}^{13}C$ ) $E = 50$ ; $Q$ and $α$ (scaling parameter) dependence of calculated $σ$ .

Elastic and inelastic scattering of oxygen ions from nickel and germanium isotopes

M. E. Cobern, N. Lisbona, and M. C. Mermaz

Phys. Rev. C 13, 674 (1976) - Published 1 February, 1976

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The elastic and inelastic cross sections for the scattering of ${}^{16, 18}O$ ions from targets of ${}^{72, 74, 76}{Ge}$ and of ${}^{16}O$ from ${}^{64}{Ni}$ have been measured at a laboratory energy of 56 MeV. The angular distributions for the ground and first-excited ( $2^{+}$ ) levels have been analyzed simultaneously by a coupled-equations search routine, and optical potentials determined. It is shown that this method reduces the ambiguity in the potentials.

NUCLEAR REACTIONS ${}^{64}{Ni}$ , ${}^{72, 74, 76}{Ge}$ ( ${}^{16}O$ , ${}^{16}{O'}$ ), ${}^{72, 74, 76}{Ge}$ ( ${}^{18}O$ , ${}^{18}O$ ), and ( ${}^{18}O$ , ${}^{18}{O'}$ ); measured $σ (θ)$ , $E = 56$ MeV; coupled equations analysis; derived 6-parameter optical potentials, deformation parameters.

Deep inelastic nucleon transfer in ${}^{16}O$ + ${}^{27}{Al}$ reactions at 90 and 100 MeV

T. M. Cormier, A. J. Lazzarini, M. A. Neuhausen, A. Sperduto, K. Van Bibber, F. Videbaek, G. Young, E. B. Blum, L. Herreid, and W. Thoms

Phys. Rev. C 13, 682 (1976) - Published 1 February, 1976

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Reactions induced by ${}^{16}O$ bombardment of ${}^{27}{Al}$ have been investigated using a time-of-flight spectrometer for $E ({}^{16}O) = 90 and 100$ MeV. Systematics of the angular distributions vs mass transfer and $Q$ value suggest that frictional collisions are important in the transfer channels. The magnitude of deep inelastic cross sections and quasielastic cross sections are compared with previous fusion cross section measurements and limiting angular momenta are deduced.

NUCLEAR REACTIONS ${}^{27}{Al} ({}^{16}O, M)$ for mass of $M = 6$ through 22 amu, $E ({}^{16}O) = 90, 100$ MeV, ${}^{27}{Al}$ ( ${}^{16}O$ , ${}^{16}O$ ), ${}^{27}{Al}$ ( ${}^{16}O$ , C), ${}^{27}{Al}$ ( ${}^{16}O$ , N), ${}^{27}{Al}$ ( ${}^{16}O$ , O), $E ({}^{16}O) = 100$ MeV. Measured $σ (E_{M}, θ_{M})$ , $Q$ values, total reaction cross section.

High-spin states of the $K^{π} = {\frac{3}{2}}^{+} and {\frac{1}{2}}^{+}$ bands of ${}^{23}{Na}$

D. E. Gustafson, S. T. Thornton, T. C. Schweizer, J. L. C. Ford, Jr., P. D. Miller, R. L. Robinson, and P. H. Stelson

Phys. Rev. C 13, 691 (1976) - Published 1 February, 1976

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The ${}^{12}C ({}^{15}N, α) {}^{23}{Na}$ reaction was used to populate high-spin states in ${}^{23}{Na}$ for incident ${}^{15}N$ $E_{lab} = 36 to 39$ MeV. Angular distributions of the reaction $α$ particles were measured and energy averaged $σ (θ)' s$ have been compared to Hauser-Feshbach calculations. We present suggestions for the high-spin members of the $K^{π} = {\frac{3}{2}}^{+}$ ground-state rotational band through the ${\frac{21}{2}}^{+}$ member and for the $K^{π} = {\frac{1}{2}}^{+}$ band through the ${\frac{17}{2}}^{+}$ member. The proposed spin assignments are in good agreement with shell model calculations.

NUCLEAR REACTIONS ${}^{12}C ({}^{15}N, α)$ , $E_{lab} = 36 to 39.2$ MeV, measured $o (E)$ for $θ_{lab} = 7 °$ ; $E_{lab} = 36.4, 37.2, 38.0, 38.8$ MeV, measured $σ (θ)$ ; ${}^{23}{Na}$ deduced levels. Hauser-Feshbach calculations and suggested $J$ values. Natural targets.

Two-nucleon transfer reactions induced by ${}^{16}O$ on ${}^{42}{Ca}$ and ${}^{48}{Ca}$

Y. Eisen, H. T. Fortune, W. Henning, D. G. Kovar, S. Vigdor, and B. Zeidman

Phys. Rev. C 13, 699 (1976) - Published 1 February, 1976

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The reactions ${}^{42, 48}{Ca}$ ( ${}^{16}O$ , ${}^{18}O$ ) ${}^{40, 46}{Ca}$ and ${}^{42, 48}{Ca}$ ( ${}^{16}O$ , ${}^{14}C$ ) ${}^{44, 50}{Ti}$ were studied at 56-MeV bombarding energy. Angular distributions for transitions to the ground and excited states of the residual nuclei and of the outgoing particles are analyzed in the framework of both "cluster" and microscopic distorted-wave Born-approximation calculations. The measured transfer cross sections are not described by calculations using optical-model parameters which fit elastic scattering. Agreement is substantially improved by a systematic change in the exit channel parameters. Cross sections for excited states relative to ground-state transitions are compared to relative strengths obtained from light-ion reactions and from simple shell-model calculations.

NUCLEAR REACTIONS ${}^{48, 42}{Ca}$ ( ${}^{16}O$ , ${}^{18}O$ ) and ${}^{48, 42}{Ca}$ ( ${}^{16}O$ , ${}^{14}C$ ), $E_{lab} = 56$ MeV, $4 ° \leq θ_{c . m .} \leq 70 °$ . Measured $σ (θ)$ . Exact finite-range DWBA analysis. Deduced relative spectroscopic factors for ${}^{18}O$ , ${}^{46}{Ca}$ , ${}^{44}{Ti}$ , and ${}^{50}{Ti}$ levels. Enriched targets.

Quasielastic electron scattering from ${}^{3}{He}$ and ${}^{4}{He}$

J. S. McCarthy, I. Sick, R. R. Whitney, and M. R. Yearian

Phys. Rev. C 13, 712 (1976) - Published 1 February, 1976

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Experimental quasielastic electron scattering results for ${}^{3}{He}$ and ${}^{4}{He}$ are given for 500 MeV incident electrons and a laboratory scattering angle of 60°. The dynamics of the ${}^{3}{He}$ and ${}^{4}{He}$ nuclei are discussed in light of the results.

NUCLEAR STRUCTURE ${}^{3}{He}$ , ${}^{4}{He}$ ; measured quasielastic electron scattering; $E = 500$ MeV; $θ = 60 °$ ; comparison to calculated static and Fermi-gas models.

Deuteron-carbon elastic scattering at 650 MeV

K. S. Chadha and V. S. Varma

Phys. Rev. C 13, 715 (1976) - Published 1 February, 1976

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The Glauber theory of nucleus-nucleus scattering is used to calculate the elastic differential cross section for the scattering of deuterons off carbon nuclei using two-particle scattering data as input. We obtain qualitatively better agreement with the experimental measurements of Dutton et al. than their calculations using proton-carbon optical potentials.

NUCLEAR REACTIONS ${}^{12}C (d, d)$ , $E = 650$ MeV; calculated $σ (E, θ)$ for $0 ° < θ_{lab} < 13 °$ and $σ_{T} (E)$ using $p - p$ $p - n$ scattering parameters. Compared with experimental measurements of $σ (E, θ)$ and $σ_{T} (E)$ .

Off-energy-shell continuation of the nucleon-nucleon and meson-nucleon transition matrices in the presence of inelasticities

P. U. Sauer and Alpar Sevgen

Phys. Rev. C 13, 720 (1976) - Published 1 February, 1976

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A technique for constructing the nucleon-nucleon transition matrices $T$ in the presence of inelastic channels is given. The present technique avoids the usual potential fit and continues $T$ off the energy shell directly consistent with the two-body scattering data and consistent with the properties of possible two-body bound states. The respective $T$ matrices are determined by a real symmetric matrix function $〈 E_{1} α_{1} | σ | E_{2} α_{2} 〉$ of the continuous energy variable $E$ and the discrete eigenchannel label $α$ . The on-shell part of $σ$ is given by the eigenphases; the arbitrariness of $T$ is the off-shell continuation of the phase-shift matrix $〈 E α_{1} | σ | E α_{2} 〉$ into two dimensions. The present technique of constructing $T$ makes the experimental nucleon-nucleon and meson-nucleon scattering data readily available as input for nuclear theory extended to include baryon resonances.

NUCLEAR STRUCTURE nucleon-nucleon and meson-nucleon interactions, on shell and off shell with inelasticities.

$S$ -matrix approach to hadronic atom level shifts

A. Deloff

Phys. Rev. C 13, 730 (1976) - Published 1 February, 1976

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$S$ -matrix perturbation theory accurate to all orders in the strong interaction potential is developed. The method presented is applied to the derivation of two important relations: (a) The complex level shift in a hadronic atom is expressed in terms of the logarithmic derivative of the regular wave function at the nuclear boundary; and (b) the complex level shift is related in a model independent way to the zero-energy hadron-nucleus scattering phase shift. It is shown that these two relations provide practical means for a fast and accurate evaluation of the complex level shifts and generalized scattering lengths.

NUCLEAR REACTIONS $S$ -matrix theory, hadronic atom complex level shift calculated and correlated with zero-energy phase shift.

Experimental search for condensed nuclear states

S. Frankel, W. Frati, V. Highland, O. Van Dyck, and R. Werbeck

Phys. Rev. C 13, 737 (1976) - Published 1 February, 1976

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We have studied and made use of backward (180°) elastic scattering of 600 and 800 MeV protons as the experimental tool to search for the presence of nuclear states of very high binding energy, suggested by Feenberg and Primakoff and by Lee and Wick. This method, tested on a variety of targets, found no evidence for condensed nuclei (of 100 mb cross section) at a level of $10^{- 8}$ per target nucleus.

NUCLEAR REACTIONS Upper limit to fraction of condensed nuclei in Be, C, Cu, Ta, Au, Pt targets by measurement of backscattering of 600 and 800 MeV protons.

Dependence of the off-energy-shell $T$ matrix on the total three-momentum

L. Heller, G. E. Bohannon, and F. Tabakin

Phys. Rev. C 13, 742 (1976) - Published 1 February, 1976

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The Bakamjian-Thomas form of relativistic potential theory is used to derive a constraint on the off-energy-shell two-body $T$ matrix elements. This is an equation which specifies the dependence of these matrix elements on the total three-momentum. While other formulations lead to different constraints, it is argued that this one is the most convenient. The distinction between this formula and the (irrelevant) notion of Lorentz transforming an off-energy-shell matrix element is discussed. A critical comparison is made with several formulas which have appeared in the literature in connection with the problem of scattering a $π$ meson by a nucleus.

NUCLEAR REACTIONS Relativistic potential theory; off-energy-shell $T$ matrix elements with nonzero total momentum.

Pion charge exchange on ${}^{3}H$

A. T. Hess and B. F. Gibson

Phys. Rev. C 13, 749 (1976) - Published 1 February, 1976

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We have examined the reaction ${}^{3}H (π^{+}, π^{0}) {}^{3}{He}$ using separable pion-nucleon $t$ matrices in a formalism which incorporates multiple scattering to all orders. Spin-flip effects are shown to be important. The total cross section has a maximum of about 7 mb in the neighborhood of the (3, 3) resonance.

NUCLEAR REACTIONS ${}^{3}H (π^{+}, π^{0})$ , $E = 50 - 250$ MeV; multiple-scattering theory; separable pion-nucleon t matrices; spin flip; $σ (θ)$ and $σ (E)$ .

Excitation functions of pion reactions on ${}^{14}N$ , ${}^{16}O$ , and ${}^{19}F$ through the (3,3) resonance

Norman P. Jacob, Jr. and Samuel S. Markowitz

Phys. Rev. C 13, 754 (1976) - Published 1 February, 1976

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Cross sections for pion-induced reactions of the form ( $π, π N$ ) and more complex spallation reactions of the form ( $π, X$ ) have been measured from 50-550 MeV on the target nuclei ${}^{14}N$ , ${}^{16}O$ , and ${}^{19}F$ using the secondary pion beams at the Lawrence Berkeley Laboratory 184-inch synchrocyclotron and the Clinton P. Anderson Meson Physics Facility. The dominance of the (3, 3) free-particle resonance is seen in all excitation functions determined in this work. Relative to the ${}^{12}C (π^{\pm}, π N) {}^{11}C$ reactions, the ( $π^{\pm}, π N$ ) reactions on ${}^{14}N$ , ${}^{16}O$ , and ${}^{19}F$ have magnitudes of 0.2, 1, and 0.7, respectively. The cross section ratio $R = \frac{σ (π^{-}, π^{-} n)}{σ (π^{+}, π N)} = 1.68 \pm 0.18$ for ${}^{14}N$ at 188 ± 15 MeV, 1.68 ± 0.05 for ${}^{16}O$ at 188 ± 9 MeV, and 1.68 ± 0.03 for ${}^{19}F$ at 178 ± 2 MeV incident pion energy. The results from this work are compared to previous pion work, analogous proton-induced reactions, Monte Carlo intra-nuclear cascade-evaporation calculations, and to a semiclassical nucleon charge-exchange model which convincingly explains the ( $π, π N$ ) reaction mechanism in the (3, 3) resonance region.

NUCLEAR REACTIONS ${}^{14}N (π^{\pm}, π N) {}^{13}N$ , ${}^{16}O (π^{\pm}, π N) {}^{15}O$ , ${}^{19}F (π^{\pm}, π N) {}^{18}F$ , ${}^{14}N (π^{\pm}, X) {}^{11}C$ , ${}^{16}O (π^{\pm}, X) {}^{13}N$ , ${}^{11}C$ , and ${}^{19}F (π^{\pm}, X) {}^{11}C$ , $E = 50 - 550$ MeV. Measured and calculated $σ (E)$ , comparison to nucleon charge-exchange model.

Spin of the 1248- and 1958-keV levels in ${}^{124}{Te}$ determined from gamma-gamma directional and polarization-directional correlations

M. Behar, G. García Bermúdez, A. Flevich, and M. C. Cambiaggio

Phys. Rev. C 13, 767 (1976) - Published 1 February, 1976

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Directional correlations and polarization-directional correlations have been measured for the 646-603- and 709-646-keV cascades in ${}^{124}{Te}$ populated from the decay of ${}^{124}{Sb}$ . Ge(Li) detectors were used in both spectrometers, one of them, a planar Ge(Li) detector as the linear-polarization analyzer for the $γ$ radiation. Combination of the results of these measurements gives unique spin assignments of $4^{+}$ for the 1248- and 1958-keV levels. The determined $\frac{E 2}{M 1}$ mixing ratios are: $δ (646) = 0.00 \pm 0.01$ and $δ (709) = {0.02}_{- 0.07}^{+ 0.06}$ .

RADIOACTIVITY ${}^{124}{Sb}$ ; measured $γ γ (θ)$ and $γ γ (90 ° LP)$ (linear-polarization correlation), ${}^{124}{Te}$ deduced $I$ $δ (\frac{E 2}{M 1})$ . Ge(Li) detectors.

Collective excitations in ${}^{246}{Cm}$ and the decay of ${}^{246}{Am}^{m}$

L. G. Multhauf, K. G. Tirsell, and R. A. Meyer

Phys. Rev. C 13, 771 (1976) - Published 1 February, 1976

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Intense sources of ${}^{246}{Pu}$ have been produced (through double neutron capture by ${}^{244}{Pu}$ ) for making detailed electromagnetic and conversion-electron measurements of the decay of ${}^{246}{Am}^{m}$ to levels of ${}^{246}{Cm}$ . $γ$ rays from ${}^{246}{Pu}$ decaying to ${}^{246}{Am}$ levels were identified in a chemical milking experiment. Of the 260 ${}^{246}{Cm}$ $γ$ rays observed, 97 are new and 64 have been assigned multipolarities from Si (Li) conversion-electron measurements. Some transitions were found to have strong $E 0$ components, and two pure $E 0$ transitions were observed. High-resolution $γ - γ$ -time coincidence measurements were used to establish 54 levels, from which the low-energy band structure of ${}^{246}{Cm}$ was determined. The investigation confirmed previous assignments of $K^{π} = 0^{-}, 1^{-}, and 2^{-}$ octupole bands, and a $K^{π} = 0^{+}$ band at 1175 keV. We have also identified the probable $K^{π} = 3^{-}$ octupole band, and a second $K^{π} = 0^{+}$ band at 1289 keV. The two $K^{π} = 0^{+}$ bands are discussed in terms of possible collective excitations. Other identified bands are discussed in terms of two-quasiparticle and multipole-phonon excitations.

RADIOACTIVITY ${}^{246}{Am}^{m}$ (from $β$ decay of ${}^{246}{Pu}$ produced by double neutron capture on ${}^{244}{Pu}$ ); measured $E_{γ}$ , $I_{γ}$ , $γ γ$ coin, $I_{ce}$ ; deduced levels, $J$ , $π$ , $log ft$ .

Exchange effects in the theory of radioactive decay

W. Tobocman

Phys. Rev. C 13, 790 (1976) - Published 1 February, 1976

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A nuclear reaction theory derivation of the decay width for radioactive decay by particle emission is given. Particular attention is devoted to exchange symmetry. The result is similar is form to that derived by Fliessbach using time dependent perturbation theory except that in our expression the wave function for the emitted particle is the solution of a Schrödinger equation, whereas Fliessbach finds that this function must be calculated from a Hill-Wheeler equation.

RADIOACTIVITY Width for radioactive decay by particle emission which includes effects of exchange symmetry is derived.

Perturbed beta-gamma directional correlation in ${}^{170}{Tm}$ decay

J. K. Tuli and G. T. Emery

Phys. Rev. C 13, 799 (1976) - Published 1 February, 1976

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Measurements of the perturbed directional correlation for the $1^{-}$ → $2^{+}$ → $0^{+}$ $β - γ$ cascade in ${}^{170}{Tm}$ ground state decay have been performed with a fast-slow coincidence system using a time-to-pulse-height converter and a double-focusing magnetic spectrometer. A liquid source in the form of a solution in dilute HCl was used. The unattenutated $A_{2}$ coefficient was found to be -0.179 ± 0.018 for electrons of energy $W = 1.5 m c^{2}$ ; this value, when combined with the attenuation rates observed in our samples, is consistent with most previously reported values for the time-integrated coefficient.

RADIOACTIVITY ${}^{170}{Tm}$ [from ${}^{169}{Tm} (n, γ)$ ; measured $β γ (θ, t)$ ; deduced extranuclear attenuation, unattenuated $β γ (θ)$ . Liquid source, $β$ spectrometer, plastic scintillators.

Levels in the three-hole nucleus ${}^{105}{Ag}$ and the decay of 55.5-min ${}^{105}{Cd}$

S. V. Jackson, W. B. Walters, and R. A. Meyer

Phys. Rev. C 13, 803 (1976) - Published 1 February, 1976

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The $γ$ -ray spectrum following the decay of 55.5-min ${}^{105}{Cd}$ to levels of ${}^{105}{Ag}$ has been studied by singles, coincidence, and Compton-suppressed $γ$ -ray spectroscopy. Sources were prepared by the ( $n, 2 n$ ) reaction on isotopically enriched ${}^{106}{Cd}$ sources using 14-MeV neutrons. A total of 274 $γ$ rays are attributed to the decay of ${}^{105}{Ag}$ , and ∼248 are placed in a level scheme involving 53 excited states. These data along with the results of ( ${}^{3}{He}, d$ ) and ( $p, t$ ) reaction studies were utilized to make spin and parity assignments for many of the levels. The systematics of the $Z = 47$ silver nuclides are compared with various theoretical calculations and the systematics among the $N = 58$ isotones are discussed.

[RADIOACTIVITY ${}^{105}{Cd}$ from ${}^{106}{Cd} (n, 2 n)$ ; measured $E_{γ}$ , $I_{γ}$ , $γ γ$ coin; ${}^{105}{Ag}$ deduced levels, $E_{β +}$ , $I_{β +}$ , $I_{EC}$ , $J$ , $π$ . Enriched target, Ge(Li) detectors, Compton suppression.]

Nuclear orientation of ${}^{95, 97}{Nb}$ and ${}^{95}{Zr}$ in Zr ${Fe}_{2}$

K. S. Krane, C. E. Olsen, S. S. Rosenblum, and W. A. Steyert

Phys. Rev. C 13, 831 (1976) - Published 1 February, 1976

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The angular distribution anisotropies of $γ$ rays were measured following the decays of ${}^{95, 97}{Nb}$ and ${}^{95}{Zr}$ oriented at low temperatures in the ferromagnetic Laves phase compound Zr ${Fe}_{2}$ . The magnetic hyperfine field of Nb in Zr ${Fe}_{2}$ was deduced to be 9.4 ± 1.6 T; that of Zr in Zr ${Fe}_{2}$ was estimated to be 15 ± 4 T. The nuclear magnetic moment of ${}^{97}{Nb}$ was deduced to be $| μ | = (7.5 \pm 1.4) μ_{N}$ .

RADIOACTIVITY ${}^{95, 97}{Zr}$ , ${}^{95, 97}{Nb}$ [from $Zr (n, γ)$ ; measured $γ (θ)$ from polarized nuclei; deduced magnetic field $H$ of Zr and Nb in Zr ${Fe}_{2}$ ; ${}^{97}{Nb}$ -deduced magnetic moment $μ$ ; ${}^{95}{Nb}$ , ${}^{97}{Mo}$ deduced $\frac{E 2}{M 1}$ $γ$ -ray mixing ratio $δ$ .

Beta decay of ${}^{16}C$ and ${}^{17}N$

D. E. Alburger and D. H. Wilkinson

Phys. Rev. C 13, 835 (1976) - Published 1 February, 1976

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The delayed neutron emitters ${}^{16}C$ and ${}^{17}N$ have been studied with a ${}^{3}{He}$ neutron detector and $γ$ radiations have been measured with a Ge(Li) detector. ${}^{16}C$ was formed in the reaction ${}^{14}C$ ( ${}^{18}O$ , ${}^{16}O$ ) ${}^{16}C$ with 56-MeV ${}^{18}O$ ions, and also in the reaction ${}^{11}B ({}^{7}{Li}, 2 p) {}^{16}C$ with 40-MeV ${}^{7}{Li}$ ions. The thermalized neutrons following both reactions yield together a ${}^{16}C$ half-life of 0.747 ± 0.008 sec with the well-known 4.17-sec ${}^{17}N$ activity as an accompaniment formed in the ${}^{14}C$ ( ${}^{18}O$ , ${}^{17}N$ ) ${}^{15}N$ and ${}^{11}B ({}^{7}{Li}, p) {}^{17}N$ reactions. The neutron spectra in a bare ${}^{3}{He}$ detector contain ${}^{16}C$ lines of 0.79 ± 0.03 MeV and 1.72 ± 0.05 MeV with relative intensities $\frac{I_{0.79}}{I_{1.72}} = 5.4 \pm 0.7$ in addition to ${}^{17}N$ peaks. The ${}^{16}C$ neutron groups are assigned to the $β$ decay to the known 3.36- and 4.32-MeV $1^{+}$ states of ${}^{16}N$ with branches of 84.4 ± 1.7% and 15.6 ± 1.7%, respectively.A search for $γ$ rays associated with ${}^{16}C$ forbidden $β$ decay to the $0^{-}$ , $3^{-}$ , and $1^{-}$ levels of ${}^{16}N$ at 0.121, 0.297, and 0.397 MeV, respectively, gave upper limits of 0.5%, 0.5%, and 0.7% for the respective branching ratios ( $log ft > 6.85, > 6.83, and > 6.64$ , respectively). The $log ft$ values for $β$ decay to the 3.36- and 4.32-MeV states, 3.551 ± 0.012 and 3.83 ± 0.05, respectively, compare with preliminary theoretical values of 6.49 and 3.94, respectively, due to Millener. Separate studies were made of ${}^{17}N$ decay, formed in the ${}^{15}N (t, p) {}^{17}N$ reaction at $E_{t} = 3.0$ MeV. By using an empirical neutron efficiency function, established for the ${}^{3}{He}$ detector with the ${}^{3}H (p, n) {}^{3}{He}$ reaction, $β$ -ray branches of ${}^{17}N$ to the ${}^{17}O$ neutron-emitting states at 4.55, 5.38, and 5.94 MeV were found to be 39.2 ± 2.0%, 48.0 ± 1.5%, and 7.9 ± 0.3%, respectively, in disagreement with two previously reported measurements. $γ$ -ray measurements on ${}^{17}N$ with a Ge(Li) detector yielded the following: ratio of $β$ -ray branching intensities $\frac{B_{871}}{B_{3055}} = 8.6 \pm 0.4$ ; $B_{3841} < 7 \times 10^{- 5}$ corresponding to $log ft > 8.5$ for this $β$ -ray branch, thereby more firmly fixing the ${}^{17}N$ spin as $J^{π} = {\frac{1}{2}}^{-}$ ; energy of ${}^{17}O$ second-excited state 3055.2 ± 0.3 keV; and ground-state $γ$ -ray branch from the 3055.2-keV level < 1.5%. The mirror $β$ decays of the $A = 17$ system are discussed. An incidental result is a half-life of 178.3 ± 0.4 msec for ${}^{9}{Li}$ formed in the $t ({}^{7}{Li}, p) {}^{9}{Li}$ reaction with 20-40-MeV ${}^{7}{Li}$ ions.

RADIOACTIVITY ${}^{16}C$ , ${}^{17}N$ ; measured $t_{\frac{1}{2}}$ , $E_{n}$ , $I_{n}$ , $I_{γ}$ ; deduced $log ft$ , decay schemes; compared with theory. ${}^{9}{Li}$ ; measured $t_{\frac{1}{2}}$ .

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Heavy-ion distorted-wave Born-approximation recoil to second order in a Taylor series

Elastic and inelastic scattering of oxygen ions from nickel and germanium isotopes

Deep inelastic nucleon transfer in ${}^{16}O$ + ${}^{27}{Al}$ reactions at 90 and 100 MeV

High-spin states of the $K^{π} = {\frac{3}{2}}^{+} and {\frac{1}{2}}^{+}$ bands of ${}^{23}{Na}$

Two-nucleon transfer reactions induced by ${}^{16}O$ on ${}^{42}{Ca}$ and ${}^{48}{Ca}$

Quasielastic electron scattering from ${}^{3}{He}$ and ${}^{4}{He}$

Deuteron-carbon elastic scattering at 650 MeV

Off-energy-shell continuation of the nucleon-nucleon and meson-nucleon transition matrices in the presence of inelasticities

$S$ -matrix approach to hadronic atom level shifts

Experimental search for condensed nuclear states

Dependence of the off-energy-shell $T$ matrix on the total three-momentum

Pion charge exchange on ${}^{3}H$

Excitation functions of pion reactions on ${}^{14}N$ , ${}^{16}O$ , and ${}^{19}F$ through the (3,3) resonance

Spin of the 1248- and 1958-keV levels in ${}^{124}{Te}$ determined from gamma-gamma directional and polarization-directional correlations

Collective excitations in ${}^{246}{Cm}$ and the decay of ${}^{246}{Am}^{m}$

Exchange effects in the theory of radioactive decay

Perturbed beta-gamma directional correlation in ${}^{170}{Tm}$ decay

Levels in the three-hole nucleus ${}^{105}{Ag}$ and the decay of 55.5-min ${}^{105}{Cd}$

Nuclear orientation of ${}^{95, 97}{Nb}$ and ${}^{95}{Zr}$ in Zr ${Fe}_{2}$

Beta decay of ${}^{16}C$ and ${}^{17}N$

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