Recent Articles

Shape isomers and molecular states in ${}^{32}S$

Karlheinz Langanke

Phys. Rev. C 28, 1574 (1983) - Published 1 October, 1983

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The sequences of states found in a microscopically derived ${}^{16}O$ - ${}^{16}O$ potential are identified by energies and quadrupole moments as candidates for shape isomeric and molecular bands in ${}^{32}S$ . The $B (E 2)$ transitions within and between the bands and the capture cross sections into shape isomers and molecular states are calculated.

NUCLEAR REACTIONS ${}^{32}S$ ; calculated shape isomeric and molecular bands; microscopically derived potential model; electromagnetic transitions.

Fast light-particle production for the ${}^{11}B$ + ${}^{12}C$ and ${}^{10}B$ + ${}^{13}C$ reactions

J. F. Mateja, J. Garman, and A. D. Frawley

Phys. Rev. C 28, 1579 (1983) - Published 1 October, 1983

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The fast light-particle yield for the ${}^{10}B$ + ${}^{13}C$ and ${}^{11}B$ + ${}^{12}C$ reactions has been studied at a bombarding energy of 54 MeV. The outgoing particles, whose spectra peak at an energy which corresponds approximately to the beam velocity, are attributed to projectile breakup. The predictions of a Serber-type projectile breakup model with no free parameters other than an overall normalization were compared with the shapes of the energy spectra and the angular distributions of all outgoing particles except for protons and alpha particles. For these exit channels, the breakup cross section is masked by a strong evaporation component. For those exit channels where a comparison could be made, the breakup model described the experimental data reasonably well. The magnitudes of the total breakup cross sections for the ${}^{10}B$ + ${}^{13}C$ and ${}^{11}B$ + ${}^{12}C$ systems are 290 mb and 193 mb, respectively.

NUCLEAR REACTIONS ${}^{12}C ({}^{11}B, X)$ and ${}^{13}C ({}^{10}B, X)$ , $X = p, d, t, α, {}^{6}{Li}, {}^{7}{Li}, {}^{7}{Be}, {}^{9}{Be}$ , $E = 54$ MeV, $θ = 7.5 ° to 45 °$ ; measured $\frac{d^{2} σ}{d Ω dE}$ .

Diffractional model fits of alpha transfer reactions induced by ${}^{16}O$ projectiles on ${}^{16}O$ and ${}^{28}{Si}$ target nuclei

M. C. Mermaz, F. Auger, and B. Fernandez

Phys. Rev. C 28, 1587 (1983) - Published 1 October, 1983

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The inclusive energy spectra of the ${}^{16}O$ ( ${}^{16}O$ , ${}^{12}C$ ) ${}^{20}{Ne}$ alpha transfer reaction and of the ${}^{28}{Si}$ ( ${}^{16}O$ , ${}^{12}C$ ) ${}^{32}S$ alpha transfer reactions have been studied at four different ${}^{16}O$ incident energies: 50, 60, 68, and 72 MeV. The shape of the various energy spectra and the corresponding angular distributions are reproduced by a diffractional model calculation based on mutual excitation of the two residual partners.

NUCLEAR REACTIONS Alpha transfer induced by ${}^{16}O$ on ${}^{16}O$ and ${}^{28}{Si}$ . Energy spectra and angular distributions. Diffractional model fits.

Single proton stripping reactions to ${}^{12}C$

G. H. Neuschaefer, M. N. Stephens, S. L. Tabor, and K. W. Kemper

Phys. Rev. C 28, 1594 (1983) - Published 1 October, 1983

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The stripping reactions ${}^{11}B$ (d,n) and ${}^{11}B$ ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) have been measured to determine the location of proton single particle strengths in ${}^{12}C$ . While both reactions populate states above 18 MeV excitation in ${}^{12}C$ , (d,n) strongly populates states above this energy, in contrast to ( ${}^{7}{Li}$ , ${}^{6}{He}$ ), where almost no strength is observed above 18.3 MeV. The (d,n) spectrum has peaks with the same energy centroids and widths as those observed in medium energy (p,p') measurements at 18.38±0.06 (full width at half maximum =350±60 keV) and 19.55±0.06 MeV (full width at half maximum =575±60 keV), while the peak observed at 20.62±0.06 MeV (full width at half maximum =525±60 keV) is broader than that found in proton scattering. Comparison is made between these results and those for inelastic pion and proton scattering.

NUCLEAR REACTIONS ${}^{11}B$ (d,n), $E = 12$ MeV; measured $σ (θ)$ . ${}^{12}C$ energy centroids and widths for unbound levels, deduced spectroscopic factors. ${}^{11}B$ ( ${}^{7}{Li}$ , ${}^{6}{He}$ ), $E = 34$ MeV; measured $σ (θ)$ . Deduced final single particle orbits in ${}^{12}C$ and spectroscopic factors.

Factorization of fragment-production cross sections in relativistic heavy-ion collisions

D. L. Olson, B. L. Berman, D. E. Greiner, H. H. Heckman, P. J. Lindstrom, and H. J. Crawford

Phys. Rev. C 28, 1602 (1983) - Published 1 October, 1983

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Analysis of the factorizability of several sets of fragment-production cross sections has been performed for ${}^{12}C$ , ${}^{16}O$ , ${}^{18}O$ , and ${}^{56}{Fe}$ projectiles in the 1 to 2 GeV/nucleon energy region for targets ranging from Be to U. The results of this analysis are considered in terms of geometrical concepts. No evidence is found that there is any dependence of fragmentation channel upon the impact parameter. It is found as well that the projectile dependence of the target factors is much less than that predicted by the abrasion-ablation theory, and also is less than that predicted by an excitation-decay model. Nevertheless, it appears that an excitation and decay mechanism is the dominant process in peripheral fragmentation.

NUCLEAR REACTIONS ${}^{12}C$ , ${}^{16}O$ , ${}^{18}O$ , ${}^{56}{Fe}$ projectiles, Be, C, Al, S, Ti, Cu, Ag, Sn, Ta, W, Pb, U targets. Projectile fragmentation in relativistic heavy-ion collisions. Factorization of nuclear cross sections.

Cross sections for the production of ${}^{11}C$ in C targets by ${}^{12}C$ at relativistic energies

A. R. Smith, J. B. McCaslin, J. V. Geaga, John C. Hill, and J. P. Vary

Phys. Rev. C 28, 1614 (1983) - Published 1 October, 1983

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Cross sections for the production of ${}^{11}C$ in C targets were measured using ${}^{12}C$ ions with energies of 0.40, 1.05, and 2.1 GeV/nucleon. These measurements were undertaken for the purpose of establishing primary standards for use as beam monitors. Annihilation radiation from ${}^{11}C (T_{\frac{1}{2}} = 20.34 min)$ was counted using a large volume NaI detector. Cross sections of 63.5±0.5, 57.4±0.4, and 60.9±0.6 mb, respectively, were obtained for 0.40, 1.05, and 2.1 GeV/nucleon ${}^{12}C$ beams. The results are compared with earlier measurements of the cross sections in C targets using relativistic proton and $α$ beams. Good agreement is found between the cross sections measured in this work and a simple Glauber theory.

NUCLEAR REACTIONS ${}^{12}C ({}^{12}C, X) {}^{11}C$ : $E ({}^{12}C) = 0.40, 1.05, and 2.1$ GeV/nucleon; measured $σ$ .

Resonating group method as applied to the spectroscopy of $α$ -transfer reactions

V. B. Subbotin, V. M. Semjonov, K. A. Gridnev, and E. F. Hefter

Phys. Rev. C 28, 1618 (1983) - Published 1 October, 1983

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In the conventional approach to $α$ -transfer reactions the finite- and/or zero-range distorted-wave Born approximation is used in liaison with a macroscopic description of the captured $α$ particle in the residual nucleus. Here the specific example of ${}^{16}O$ ( ${}^{6}{Li}$ ,d) ${}^{20}{Ne}$ reactions at different projectile energies is taken to present a microscopic resonating group method analysis of the $α$ particle in the final nucleus (for the reaction part the simple zero-range distorted-wave Born approximation is employed). In the discussion of suitable nucleon-nucleon interactions, force number one of the effective interactions presented by Volkov is shown to be most appropriate for the system considered. Application of the continuous analog of Newton's method to the evaluation of the resonating group method equations yields an increased accuracy with respect to traditional methods. The resonating group method description induces only minor changes in the structures of the angular distributions, but it does serve its purpose in yielding reliable and consistent spectroscopic information.

NUCLEAR STRUCTURE ${}^{16}O$ ( ${}^{6}{Li}$ ,d) ${}^{20}{Ne}$ ; $E = 20 to 32$ MeV; calculated $B (E 2)$ ; reduced widths, $\frac{d σ}{d Ω}$ ; extracted $α$ -spectroscopic factors. ZRDWBA with microscope RGM description of residual $α$ particle in ${}^{20}{Ne}$ ; application of continuous analog of Newton's method; tested and applied Volkov force No. 1; direct mechanism.

Some gross features of the interaction of semirelativistic ${}^{16}O$ and ${}^{12}C$ ions with ${}^{197}{Au}$ targets

H. A. Khan, T. Lund, P. Vater, R. Brandt, and J. W. N. Tuyn

Phys. Rev. C 28, 1630 (1983) - Published 1 October, 1983

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Fission and total observable cross sections have been measured for the interaction of 107 MeV/N ${}^{16}O$ and 86 MeV/N ${}^{12}C$ ions with ${}^{197}{Au}$ targets using various solid-state—nuclear-track detectors, e.g., mica and CR-39 plastic. Some results on the emission of light reaction products are also presented.

NUCLEAR REACTIONS Semirelativistic heavy ions, Au targets, fission cross section, high multiplicities.

Measurement of the ${}^{232}{Th} (n, f)$ subthreshold and near-subthreshold cross section

R. B. Perez, G. de Saussure, J. H. Todd, T. J. Yang, and G. F. Auchampaugh

Phys. Rev. C 28, 1635 (1983) - Published 1 October, 1983

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A measurement of the ${}^{232}{Th} (n, f)$ cross section for incident neutron energies between 100 eV and 1.6 MeV has been performed at the Oak Ridge National Laboratory electron linear accelerator. The weak subthreshold fission cross section found in this measurement confirms the model of a low first barrier in the triple-humped fission barrier which has been theoretically predicted for the ( ${}^{232}{Th}$ +n) system. However, the appearance of a series of plateaus in the near-threshold fission cross section region presents a challenge to current barrier calculations in the ${}^{233}{Th}$ compound nucleus.

NUCLEAR REACTIONS ${}^{232}{Th} (n, f)$ measured cross section $E = 100 eV to 1.6 MeV$ .

Nuclear temperature effects in the scission-point model of nuclear fission

J. Moreau, K. Heyde, and M. Waroquier

Phys. Rev. C 28, 1640 (1983) - Published 1 October, 1983

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According to the scission-point model, the probability for a particular fission event can be expressed in terms of the collective potential and the collective kinetic energy at the scission point. Two additional assumptions make the scission-point model an easily calculable model: the assumption of equal collective kinetic energies for constant distances $d$ between the tips of the fragments, and the assumption that one is able to characterize the excitation energy of the fragments with a nuclear temperature $T$ , independent of both the mass ratio and the charge ratio, and of the deformations of the fragments. It is pointed out that the latter assumption violates energy conservation. A modified, recursive procedure is proposed, resulting in an "energy conservation consistent" scission-point method. Mass and charge distributions for the fission of ${}^{235}U$ and ${}^{252}{Cf}$ compound systems have been calculated and compared with distributions following the "standard" scission-point method of Wilkins, Steinberg, and Chasman.

NUCLEAR REACTIONS Scission-point model. Collective potential and intrinsic excitation energy. Nuclear temperature $T$ . Mass and charge distributions. Fission of ${}^{235}U$ and ${}^{252}C$ .

Precompound analyses of spectra and yields following nuclear capture of stopped $π^{-}$

M. Blann

Phys. Rev. C 28, 1648 (1983) - Published 1 October, 1983

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The hybrid model has been modified for application in the energy region involved in capture of stopped negative pions (140 MeV). Comparisons of the improved formulation have been made with data from reactions induced by protons up to 164 MeV and the agreement was good. The model was used to predict n and p spectra and activation yields from stopped $π^{-}$ capture on targets from ${}^{12}C$ to ${}^{209}{Bi}$ , assuming a predominant quasideuteron capture mechanism. Predictions are given for primary versus secondary emission contributions to the spectra. Qualitative predictions for nn, np, and pp angular correlations are presented. Sensitivity of spectra and yields to parameters related to the nuclear density at which capture occurs is illustrated. While overall comparisons between calculated and experimental results are quite satisfactory, more detailed analyses suggest that a geometry dependent formulation integrating along the density profile for $π^{-}$ capture will be necessary, coupled with explicit treatment of enhanced nucleon emission probability versus nucleon induced reactions (due to momentum differences in the entrance channels) if such model results are to simultaneously reproduce particle spectra and yields.

NUCLEAR REACTIONS Reactions induced by stopped $π^{-}$ ; calculate proton and neutron emission spectra and yields ${}^{12}C$ to ${}^{209}{Bi}$ targets using hybrid plus Weisskopf models.

Dirac-eikonal scattering amplitude

R. D. Amado, J. Piekarewicz, D. A. Sparrow, and J. A. McNeil

Phys. Rev. C 28, 1663 (1983) - Published 1 October, 1983

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The fixed energy Dirac equation using scalar plus fourth component vector potentials is solved in the eikonal limit. The Dirac-eikonal amplitude can be written in the familiar integral over impact parameter form. Results of model calculations using the Dirac-eikonal amplitude are compared with those of a partial wave solution for parameters appropriate to intermediate energy proton nucleus scattering.

NUCLEAR REACTIONS Intermediate energy. Dirac-eikonal amplitude, Dirac impulse approximation.

Hypernuclear excitation through kaon photoproduction

Shian S. Hsiao and Stephen R. Cotanch

Phys. Rev. C 28, 1668 (1983) - Published 1 October, 1983

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The $Λ$ hypernuclear spectrum excited in the weakly interacting electromagnetic production process $A {(γ, K^{+})}_{Λ} B$ is theoretically surveyed. Plane wave impulse approximated multiple-scattering calculations for hypernuclear formation from ${}^{4}{He}$ , ${}^{12}C$ , and ${}^{208}{Pb}$ targets are presented for a wide range of lab and excitation energies. Excitation energies and transition densities are calculated within a lambda-particle, proton-hole model using Woods-Saxon basis wave functions. The transition operator is constructed using the free (bare) amplitudes for the elementary process $γ + p \to K^{+} + Λ$ which are evaluated from Feynman diagrams including both strange meson (K,K*) and baryon ( $Λ, Σ$ ) exchange. These amplitudes are dominated by $Λ$ and scalar K exchange; however, effects from $Σ$ and vector K* exchange are found to be significant even near threshold. The hypernuclear selective excitation is documented in detail for $θ = 0 °$ . Transitions to unnatural parity states and substitutional states with medium to high spin are predicted to be strong. Because of large momentum transfer (≥200 MeV/c), the ( $γ$ , K) reaction is highly quasielastic and a low, roughly 0.1, $Λ$ "sticking probability" is estimated using an approximate hypernuclear sum rule. The excitation process is sensitive to the interior as cross section calculations for ${}^{208}{Pb} (γ, K^{+}) {}_{Λ}^{208}{Tl}$ involving bound $Λ$ , $1 s$ , $2 s$ , and $3 s$ configurations, unrestricted by the Pauli exclusion principle, reveal markedly different signatures. Cross section sensitivity is also investigated and discussed for off-shell amplitude effects, variations in the $Λ$ -nucleus spin-orbit interaction, and different sets of phenomenological coupling constants which equivalently describe the $γ + p \to K^{+} + Λ$ process. Finally, estimates for electroproduction, $A {(e, e^{'} K^{+})}_{Λ} B$ , are also presented and discussed. Both photoproduction and electroproduction cross sections are calculated to be measurably large for the beam energies, 1 to 3 GeV, of proposed intense electron accelerators.

NUCLEAR REACTIONS Kaon photoproduction and $Λ$ hypernuclear formation. Theoretical survey of $σ (E_{lab}, E_{x})$ for ${}_{Λ}^{4}H$ , ${}_{Λ}^{12}B$ , and ${}_{Λ}^{208}{Tl}$ . Plane wave impulse approximation and particle-hole wave functions. Investigation of cross section sensitivity to theoretical uncertainties. Application of hypernuclear sum rule. Electroproduction hypernuclear cross section estimates.

Stochastic solution of a model meson-nucleon field theory

Brian D. Serot, S. E. Koonin, and J. W. Negele

Phys. Rev. C 28, 1679 (1983) - Published 1 October, 1983

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Ground-state properties in a model quantum field theory are calculated by stochastic evaluation of a path integral representation of the many-body propagator. The model consists of nonrelativistic nucleons coupled to vector and scalar mesons in one spatial dimension. Binding energies and density distributions are calculated for bound states of up to twenty nucleons. The binding energy as a function of density, the nucleon-nucleon correlation function, and the meson-meson correlation function are evaluated in nuclear matter. Exact ground-state solutions to the full field theory are shown to differ relatively little from those of the potential theory corresponding to the static limit. The exact solutions differ substantially from those of the mean-field (Hartree) approximation, but are quite similar to those obtained in the Hartree-Fock approximation.

NUCLEAR STRUCTURE Meson-nucleon field theory. Monte Carlo solution. Nuclear matter.

Neutron energy-angle distributions from 800 MeV proton-proton inelastic scattering

T. Rupp, R. Carlini, B. Dieterle, J. Donahue, C. Leavitt, W. Thomas, D. Wolfe, L. B. Auerbach, V. L. Highland, K. F. Johnson, W. K. McFarlane, J. Pratt, and R. F. Bentley

Phys. Rev. C 28, 1696 (1983) - Published 1 October, 1983

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Complete neutron double differential cross sections, ( $\frac{d^{2} σ}{d Ω dE}$ ) ( $θ, E$ ), have been measured for the reaction $p + p \to n + p + π^{+}$ . Approximately 200 000 events have been collected, resulting in cross sections of approximately 10 percent accuracy. The energy spectrum at all angles shows an enhancement that is consistent with large amounts of $Δ^{+ +} (1232)$ isobar production followed by the decay $Δ^{+ +} \to p + π^{+}$ . At the peak of the enhancement $\frac{d^{2} σ}{d Ω dE}$ in the c.m. drops smoothly from 50 μb ${sr}^{- 1}$ Me $V^{- 1}$ at 0° to 15 μb ${sr}^{- 1}$ ${MeV}^{- 1}$ at 90°. The c.m. angular distributions for fixed $p π^{+}$ recoil mass are of the form $A + B {cos}^{2} θ + C {cos}^{4} θ$ with $C$ consistent with zero, in qualitative agreement with the Mandelstam model. Some recent models give reasonable fits to the data with few parameters. The total integrated cross section is found to be $σ (p p \to np π^{+}) = 16.0 \pm 1.5$ mb.

NUCLEAR REACTIONS Nucleon-nucleon interactions $p + p \to π^{+} + p + n$ , $E = 800$ MeV; measured $σ$ , $σ (E_{n}, θ_{n})$ for $n$ in forward hemisphere of c.m.s. Compared with models.

Mass of ${}^{59}{Zn}$

B. Sherrill, K. Beard, W. Benenson, B. A. Brown, E. Kashy, W. E. Ormand, H. Nann, J. J. Kehayias, A. D. Bacher, and T. E. Ward

Phys. Rev. C 28, 1712 (1983) - Published 1 October, 1983

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The ground state $Q$ value of the reaction ${}^{58}{Ni} (p, π^{-}) {}^{59}{Zn}$ has been measured with $E_{p} = 190$ MeV. The measured $Q$ value was -144.735(40) MeV and the cross section at 30 deg was found to be 0.080(20) nb/sr. Also measured was the low-lying level structure of ${}^{59}{Zn}$ and an upper limit on the reaction cross section for ${}^{40}{Ca} (p, π^{-})$ going to the ground state of ${}^{41}{Ti}$ . The measured mass of ${}^{59}{Zn}$ was used to study Coulomb energy systematics.

NUCLEAR REACTIONS ${}^{58}{Ni} (p, π^{-}) {}^{59}{Zn}$ , ${}^{40}{Ca} (p, π^{-}) {}^{41}{Ti}$ , $E_{p} = 190$ MeV; measured ${}^{59}{Zn}$ mass, low-lying energy levels; calculated $ft$ values, $σ$ . Studied Coulomb energy systematics.

Target dependence of charge distributions in spallation reactions of medium-mass nuclei with 12 GeV protons

T. Asano, Y. Asano, Y. Iguchi, H. Kudo, S. Mori, M. Noguchi, Y. Takada, H. Hirabayashi, H. Ikeda, K. Katoh, K. Kondo, M. Takasaki, T. Tominaka, and A. Yamamoto

Phys. Rev. C 28, 1718 (1983) - Published 1 October, 1983

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Spallation yields of Ti, Fe, Co, Ni, Cu, and Zn by 12 GeV protons were measured with a Ge(Li) $γ$ -ray spectrometer followed by computer analysis of the spectra. The measured cross sections of about 30 product nuclides for each target sample are in general agreement with existing data in the same energy range and cover a wider mass range of the product nuclides for most of the targets. The present data were used to obtain the charge-dispersion and mass-yield curves by the leastsquares analysis. The target dependence of charge distributions in spallation reactions for product nuclides with a mass range $22 ≲ A ≲ 58$ was determined as a function of the $\frac{N}{Z}$ ratio of the target, ${(\frac{N}{Z})}_{T}$ . The $\frac{N}{Z}$ ratio at the charge-dispersion peak, ${(\frac{N}{Z})}_{p}$ , can be expressed as ${(\frac{N}{Z})}_{p} = (0.783 \pm 0.038) + (0.304 \pm 0.033) {(\frac{N}{Z})}_{T}$ . The present results of the target dependence of charge distributions do not seem to agree with the earlier data for production of argon isotopes by 24 GeV protons in the same target mass range.

NUCLEAR REACTIONS Ti, Fe, Co, Ni, Cu, Zn (p, spallation), $E = 12$ GeV, activation, Ge(Li) detector, cross sections for $7 ≲ A ≲ 65$ , target $\frac{N}{Z}$ dependence of charge distribution of spallation products.

Propagator nonlocalities in nuclear photopion reactions

G. Toker and F. Tabakin

Phys. Rev. C 28, 1725 (1983) - Published 1 October, 1983

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The coordinate-space distorted-wave impulse approximation approach to ( $γ, π$ ) and ( $π, γ$ ) reactions on light nuclei is extended to include the full nonlocality of the pion, nucleon, and isobar propagators that appear in the photoproduction operator. Whereas the introduction of the pionpropagator nonlocality always produces a large effect on the corresponding term of the nuclear photopion amplitude, the other nonlocalities affect mainly the relative phases of the appropriate contributions leaving their magnitude almost unchanged. As a result, in a nucleus like ${}^{12}C$ , where at low energies one diagram (the contact term) accounts for most of the cross section and the pion-pole term is not very important, there is almost no change compared with the local calculation. On the other hand, in the nuclei ${}^{13}C$ and ${}^{15}N$ , where an appreciable interference occurs between the contact and pion-pole diagrams, the nonlocality effect is quite large. Particularly affected is the reaction on the nucleus ${}^{14}N$ , even at very low energies. Our treatment blends coordinate- and momentum-space techniques and hence allows one to incorporate other effects such as medium corrections or pionnucleon form factors. Comparison with available data is also discussed.

NUCLEAR REACTIONS ( $γ, π$ ) and ( $π, γ$ ) calculations for ${}^{14}N$ , ${}^{12}C$ , ${}^{13}C$ , and ${}^{15}N$ .

Delayed neutron precursors at masses 97-99 and 146-148

P. L. Reeder and R. A. Warner

Phys. Rev. C 28, 1740 (1983) - Published 1 October, 1983

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Delayed neutron emission probabilities, $P_{n}$ , have been measured for ${}^{98, 99}{Sr}$ , ${}^{97}Y^{g, m}$ , ${}^{96}Y^{g}$ , ${}^{99}Y$ , ${}^{147}{Ba}$ , and ${}^{147, 148}{La}$ . This is the first reported measurement for ${}^{97}Y^{m}$ . Upper limits to the $P_{n}$ for ${}^{97}{Sr}$ , ${}^{146, 148}{Ba}$ , and ${}^{146}{La}$ were established. The $P_{n}$ values measured here are much smaller than a set of published measurements. Calculations of total delayed neutron yields from fission are consistent with experimental measurements of total delayed neutron yields except for fast neutron fission of ${}^{238}U$ . Improved half-lives are reported for 13 of the Rb, Sr. Y, Cs, Ba, and La nuclides at masses 97-99 and 146-148.

RADIOACTIVITY ${}^{97 - 99}{Rb}$ , ${}^{97 - 99}{Sr}$ , ${}^{97 - 99}Y$ , ${}^{146, 147}{Cs}$ , ${}^{147, 148}{Ba}$ , ${}^{147, 148}{La}$ [from ${}^{235}U (n, f)$ ]; measured $t_{\frac{1}{2}}$ , $P_{n}$ ; on-line mass separation, n, $β$ multiscaling.

Measurement of positron polarization in the unique second forbidden transition of ${}^{22}{Na}$

M. Skalsey, T. A. Girard, and A. Rich

Phys. Rev. C 28, 1752 (1983) - Published 1 October, 1983

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The polarization of positrons in the $3^{+}$ → $0^{+}$ unique second forbidden decay of ${}^{22}{Na}$ has been measured relative to the allowed decay of ${}^{68}{Ga}$ with the result $P_{L} = β (1.00 \pm 0.05)$ . This is the first measurement of $P_{L}$ in a unique second forbidden decay and the third such determination in any unique decay. The method employed our newly introduced positron polarization comparator. The implications of this measurement, the possibility of its improvement, and extension of the technique to the unique first forbidden $β^{+}$ decay of ${}^{84}{Rb}$ are discussed.

RADIOACTIVITY Measured positron polarization in the unique, second forbidden transition of ${}^{22}{Na}$ .

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Shape isomers and molecular states in ${}^{32}S$

Fast light-particle production for the ${}^{11}B$ + ${}^{12}C$ and ${}^{10}B$ + ${}^{13}C$ reactions

Diffractional model fits of alpha transfer reactions induced by ${}^{16}O$ projectiles on ${}^{16}O$ and ${}^{28}{Si}$ target nuclei

Single proton stripping reactions to ${}^{12}C$

Factorization of fragment-production cross sections in relativistic heavy-ion collisions

Cross sections for the production of ${}^{11}C$ in C targets by ${}^{12}C$ at relativistic energies

Resonating group method as applied to the spectroscopy of $α$ -transfer reactions

Some gross features of the interaction of semirelativistic ${}^{16}O$ and ${}^{12}C$ ions with ${}^{197}{Au}$ targets

Measurement of the ${}^{232}{Th} (n, f)$ subthreshold and near-subthreshold cross section

Nuclear temperature effects in the scission-point model of nuclear fission

Precompound analyses of spectra and yields following nuclear capture of stopped $π^{-}$

Dirac-eikonal scattering amplitude

Hypernuclear excitation through kaon photoproduction

Stochastic solution of a model meson-nucleon field theory

Neutron energy-angle distributions from 800 MeV proton-proton inelastic scattering

Mass of ${}^{59}{Zn}$

Target dependence of charge distributions in spallation reactions of medium-mass nuclei with 12 GeV protons

Propagator nonlocalities in nuclear photopion reactions

Delayed neutron precursors at masses 97-99 and 146-148

Measurement of positron polarization in the unique second forbidden transition of ${}^{22}{Na}$

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