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Highly excited states in ${}^{6}{Li}$ by the reaction ${}^{9}{Be} (p, α) {}^{6}{Li}$

T. Delbar, G. Grégoire, J. Lega, G. Paic, and P. Wastyn

Phys. Rev. C 14, 1659(R) (1976) - Published 1 October, 1976

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The spectra from the reaction ${}^{9}{Be} (p, α) {}^{6}{Li}$ induced by 75 and 30 MeV protons were recorded at $θ_{α} = 20 and 30 °$ in the laboratory frame. The region from 6 to 18 MeV excitation energy of the residual nucleus was carefully studied for possible levels. Evidence for a $T = 1$ level at $E_{x} = 8.2 \pm 0.2$ MeV with a width $Γ = 2.2 \pm 0.2$ MeV is reported. No other levels were observed in the present spectra.

NUCLEAR REACTIONS ${}^{9}{Be} (p, α)$ , $E = 30 - 75$ MeV, measured $σ (E, θ)$ ; phasespace analysis; deduced level in ${}^{6}{Li}$ .

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Extraction of single-particle energies from experiment

David Gloeckner and Larry Zamick

Phys. Rev. C 14, 1662(R) (1976) - Published 1 October, 1976

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We examine the prescription for obtaining single-particle splittings at a closed minor shell, i.e., $ε - ε^{'} = E (N + 1, Z) + E (N - 1, Z) - 2 E (N, Z)$ . We find that to understand the value obtained, especially if the minor shell nucleus is deformed, e.g., ${}^{12}C$ , we have to introduce many-particle-many-hole correlations. These correlations are less important although not negligible in the vicinity of a good closed shell, like ${}^{48}{Ca}$ .

NUCLEAR STRUCTURE The influence of many particle-many hole correlations on single particle energies, especially for closed minor shells.

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Excitation of the giant dipole resonance in ${}^{12}C (π, π^{'}) {}^{12}C^{*}$

Hans J. Pirner

Phys. Rev. C 14, 1665(R) (1976) - Published 1 October, 1976

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We apply Glauber theory to calculate the cross section for the excitation of the giant dipole resonance ( $1^{-}$ ) in ${}^{12}C$ by pions. In the resonance region the cross section $σ_{GDR} = 1.7$ mb. It is too small to influence the ratio of the ( $π, π N$ ) reaction. This result contradicts previous speculations.

NUCLEAR REACTIONS ${}^{12}C (π, π^{'}) {}^{12}C^{*}$ , $E = 180$ MeV, calculated $σ (E)$ for giant dipole, discussed relevance for ( $π, π N$ ) reaction.

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Exact finite-range CCBA calculations for the reaction ${}^{16}O (d, {}^{6}{Li}) {}^{12}C$ at $E_{d} = 35$ MeV

P. Nagel and R. D. Koshel

Phys. Rev. C 14, 1667(R) (1976) - Published 1 October, 1976

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The reaction ${}^{16}O (d, {}^{6}{Li}) {}^{12}C$ at 35 MeV has been analyzed with a finite-range coupled channel Born approximation code. Agreement in shape and normalization is found if the interaction radius for the cluster system ${}^{12}C + α$ is taken to be $R = 1.27 (12^{\frac{1}{3}} + 4^{\frac{1}{3}})$ fm.

[NUCLEAR REACTIONS CCBA; $α$ transfer. Applied ${}^{16}O (d, {}^{6}{Li}) {}^{12}C$ ; $E = 35$ MeV.]

Unnatural parity levels at high excitation in ${}^{20}{Ne}$

L. K. Fifield, R. W. Zurmühle, and D. P. Balamuth

Phys. Rev. C 14, 1010 (1976) - Published 1 September, 1976

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$γ$ decaying states at high excitation in ${}^{20}{Ne}$ have been studied via the ${}^{12}C ({}^{12}C, α γ) {}^{20}{Ne}$ reaction in an attempt to identify new unnatural parity levels in ${}^{20}{Ne}$ . In addition to $γ$ -ray decay schemes, accurate measurements of the ratio of cross sections at average scattering angles of 12° and 1° were made, and the combination of a strong $γ$ decay mode and vanishing cross section at 0° were taken as the signature of an unnatural parity level. Previously suggested unnatural parity levels at 9.88 ± 0.03, 10.69 ± 0.02, 11.56 ± 0.02, and 11.67 ± 0.03 MeV have been confirmed, and limits on their spins and parities have been established from the $γ$ ray decay schemes. The results are compared with shell model calculations.

NUCLEAR REACTIONS ${}^{12}C ({}^{12}C, α)$ , $E = 30$ MeV, $θ_{α} = 0 °, 12 °$ ; measured coincident $γ$ spectrum. ${}^{20}{Ne}$ deduced branching ratios, probable $J^{π}$ .

Lifetimes of yrast states in ${}^{51}{Ti}$ , ${}^{52}{Ti}$ , and ${}^{52}V$

B. A. Brown, D. B. Fossan, A. R. Poletti, and E. K. Warburton

Phys. Rev. C 14, 1016 (1976) - Published 1 September, 1976

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The ${}^{6}{Li}$ and ${}^{7}{Li}$ bombardment of ${}^{48}{Ca}$ in conjunction with recoil distance measurements has been used to measure the mean lifetimes of excited states in ${}^{51}{Ti}$ , ${}^{52}{Ti}$ , and ${}^{52}V$ : in ${}^{51}{Ti}$ , 2754-keV level ( $τ = 1.2 \pm 0.4$ nsec) and 2344-keV level ( $τ = 13.9 \pm 2.3$ psec); in ${}^{52}{Ti}$ , 3027-keV level ( $τ = 36.7 \pm 6.3$ psec); in ${}^{52}V$ , 2541-keV level ( $τ = 7.7 \pm 0.5$ psec). The $γ$ -ray decay schemes and lifetimes are consistent with an interpretation involving yrast states of the ${(π 1 f_{\frac{7}{2}})}^{n} \otimes {(ν 2 p_{\frac{3}{2}}, 1 f_{\frac{5}{2}}, 2 p_{\frac{1}{2}})}^{m}$ configuration where $n = 2 or 3$ and $m = 1 or 2$ . The experimental level energies and $B (E 2)$ values are compared with shell model calculations by Horie and Ogawa.

NUCLEAR REACTIONS ${}^{48}{Ca} ({}^{6}{Li}, p 2 n)$ $E_{{}^{6}{Li}} = 26$ MeV; ${}^{48}{Ca} ({}^{7}{Li}, p 3 n)$ , ${}^{48}{Ca} ({}^{7}{Li}, p 2 n)$ , ${}^{48}{Ca} ({}^{7}{Li}, 3 n)$ $E_{{}^{7}{Li}} = 28$ MeV; measured $γ$ excitations, recoil distance; deduced $T_{\frac{1}{2}}$ , $B (E 2)$ , effective charges, decay scheme in ${}^{51}{Ti}$ , ${}^{52}{Ti}$ , ${}^{52}V$ ; enriched target, Ge(Li) detectors.

High-spin states and neutron-hole influence in ${}^{209}{At}$

T. P. Sjoreen, G. Schatz, S. K. Bhattacherjee, B. A. Brown, D. B. Fossan, and P. M. S. Lesser

Phys. Rev. C 14, 1023 (1976) - Published 1 September, 1976

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The properties of high-spin states in ${}^{209}{At}$ have been studied with the ${}^{206}{Pb} ({}^{6}{Li}, 3 n γ) {}^{209}{At}$ At reaction. In-beam measurements with Ge(Li) detectors of $γ$ -ray excitation functions, $γ - γ$ coincidences, $γ$ -ray angular distributions, and pulsed beam- $γ$ timing were made to establish decay schemes, level energies, spin-parity assignments, isomeric lifetimes, and magnetic moments. High-spin states involving three valence protons in the $1 h_{\frac{9}{2}}$ , $2 f_{\frac{7}{2}}$ , or $1 i_{\frac{13}{2}}$ orbitals were identified. The electromagnetic properties observed in ${}^{209}{At}$ were compared with those in the closed-neutron core nucleus ${}^{211}{At}$ to examine the influence of the two neutron holes on the proton structure; microscopic calculations of this influence were carried out in perturbation theory.

NUCLEAR REACTIONS ${}^{206}{Pb} ({}^{6}{Li}, 3 n γ)$ , $E_{Li} = 29 - 34$ MeV; measured $γ$ -excitations, $γ - γ$ coincidences, $γ - W (θ)$ , pulsed beam- $γ$ timing, perturbed angular distributions; deduced level scheme, $γ$ multipolarities, $J^{π}$ , $T_{\frac{1}{2}}$ , $B (E 2)$ , $g$ factor; perturbation calculations.

Inelastic effects in heavy-ion one-neutron transfer on ${}^{26}{Mg}$

D. Sinclair, B. T. Chait, S. Kahana, and B. S. Nilsson

Phys. Rev. C 14, 1033 (1976) - Published 1 September, 1976

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The ${}^{26}{Mg}$ ( ${}^{13}C$ , ${}^{12}C$ ) ${}^{27}{Mg}$ and ${}^{26}{Mg}$ ( ${}^{13}C$ , ${}^{14}C$ ) ${}^{25}{Mg}$ reactions have been studied at 35 MeV incident energy. Since distorted wave Born approximation calculations fail to fit many features of the data, the effects of inelastic excitation of the target and projectile systems are investigated and found to be important. In particular the $L = 1$ excitation of the ${\frac{3}{2}}^{+}$ state in ${}^{27}{Mg}$ state transitions is found to be anomalous in a fashion similar to that in earlier experiments using other targets and projectiles. The inclusion of a multistep route permitting a spectroscopically strong $p_{\frac{3}{2}} \to d_{\frac{3}{2}}$ transition, in addition to the one-step $p_{\frac{1}{2}} \to d_{\frac{3}{2}}$ transition, goes a long way towards removing the anomaly.

NUCLEAR REACTIONS DWBA and CCBA analysis of $σ (θ)$ for ${}^{26}{Mg}$ ( ${}^{13}C$ , ${}^{12}C$ ) and ${}^{26}{Mg}$ ( ${}^{13}C$ , ${}^{14}C$ ); $E = 35$ MeV. Explanation of $L = 1$ anomaly in DWBA analysis.

Reactions of ${}^{40}{Ar}$ with ${}^{160}{Dy}$ , ${}^{164}{Dy}$ , and ${}^{174}{Yb}$

Y. LeBeyec, R. L. Hahn, K. S. Toth, and R. Eppley

Phys. Rev. C 14, 1038 (1976) - Published 1 September, 1976

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Excitation functions for nuclear reactions induced by ${}^{40}{Ar}$ ions were measured for the reactions ${}^{164}{Dy} ({}^{40}{Ar}, x n) {}^{204 - x}{Po}$ , ${}^{160}{Dy} ({}^{40}{Ar}, x n) {}^{200 - x}{Po}$ , ${}^{174}{Yb} ({}^{40}{Ar}, x n) {}^{214 - x}{Ra}$ , and ${}^{174}{Yb} ({}^{40}{Ar}, p x n) {}^{213 - x}{Fr}$ . For all of the systems studied, the ( $Ar, x n$ ) reactions only make up a small part of the total reaction cross section of ∼2 b; the largest cross sections encountered in each system were (at the peaks of the respective excitation functions) 30 mb for ${}^{164}{Dy} (Ar, 5 n)$ , 10 mb for ${}^{160}{Dy} (Ar, 4 n)$ , and 5 mb for ${}^{174}{Yb} (Ar, \frac{4}{n} - 5 n)$ . The probabilities $P_{xn}$ of neutron emission in the compound systems ${}^{204}{Po}$ and ${}^{200}{Po}$ were found to be very different, with respective maximum probabilities for the emission of four, five, and six neutrons of 0.064, 0.035, and 0.016 for ${}^{204}{Po}$ , and 0.010, 0.0025, and 0.0003 for ${}^{200}{Po}$ . Calculations performed with a statistical-model code, which includes angular-momentum effects and fission competition, are able to reproduce the shapes and magnitudes of the experimental excitation functions, although there is a systematic energy difference, ∼10 MeV, between theory and the data. These model-dependent analyses describe in detail how the particle evaporation and fission deexcitation modes vary with angular momentum and excitation energy. The observed large differences in $P_{xn}$ values for ${}^{204}{Po}$ and ${}^{200}{Po}$ are seen to arise from the small difference, ∼1.2 MeV, between the values of $S_{n} - B_{f}$ , the difference of neutron-separation and fission-barrier energies, in each compound system.

NUCLEAR REACTIONS ${}^{160}{Dy} ({}^{40}{Ar}, x n) {}^{200 - x}{Po}$ , ${}^{164}{Dy} ({}^{40}{Ar}, x n) {}^{204 - x}{Po}$ , ${}^{174}{Yb} ({}^{40}{Ar}, x n) {}^{214 - x}{Ra}$ , and ${}^{174}{Yb} ({}^{40}{Ar}, p x n) {}^{213 - x}{Fr}$ . $E = 160 - 270$ MeV; measured $σ (E)$ for product nuclei that are $α$ -particle radioactive; compared with statistical-model calculations.

Application of Austern-Blair theory to the interference between Coulomb and nuclear excitation in the inelastic scattering of heavy ions

C. K. Gelbke and J. G. Cramer

Phys. Rev. C 14, 1048 (1976) - Published 1 September, 1976

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The connection between elastic and inelastic scattering of heavy ions in the combined Coulomb and nuclear fields is discussed in terms of the Austern-Blair theory. It is shown that the first order distorted-wave Born-approximation inelastic scattering amplitudes may be obtained from the elastic scattering amplitudes to a good degree of accuracy. Consequently they contain essentially the same information about the nuclear potentials as the elastic scattering $S$ -matrix elements.

NUCLEAR REACTIONS Calculations of HI inelastic scattering with Coulomb-nuclear interference; comparison of DWBA with Austern-Blair approximation; cases studied ${}^{56}{Fe}$ ( ${}^{16}O$ , ${}^{16}{O'}$ ) and ${}^{26}{Mg}$ ( ${}^{16}O$ , ${}^{16}{O'}$ ); both $σ (θ)$ and $σ (E)$ .

Product yields for the photofission of ${}^{235}U$ and ${}^{238}U$ with 25-MeV bremsstrahlung

H. Thierens, D. De Frenne, E. Jacobs, A. De Clercq, P. D'hondt, and A. J. Deruytter

Phys. Rev. C 14, 1058 (1976) - Published 1 September, 1976

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The photofission of ${}^{235}U$ and ${}^{238}U$ with 25-MeV bremsstrahlung was studied. For both nuclei cumulative yields for about 40 mass chains were measured. For ${}^{235}U$ fractional independent chain yields of ${}^{126}{Sb}^{g}$ , ${}^{126}{Sb}^{m}$ , ${}^{128}{Sn}$ , ${}^{128}{Sb (9 h)}$ , ${}^{128}{Sb (10 m i n)}$ , ${}^{131}{Sb}$ , ${}^{131}{Te}^{g}$ , ${}^{131}{Te}^{m}$ , ${}^{132}I$ , ${}^{134}I$ , ${}^{135}{Xe}$ , ${}^{136}{Cs}$ , and ${}^{140}{La}$ were determined and for ${}^{238}U$ those of ${}^{128}{Sn}$ , ${}^{128}{Sb (9 h)}$ , ${}^{131}{Sb}$ , ${}^{131}{Te}^{g}$ , ${}^{131}{Te}^{m}$ , ${}^{132}I$ , ${}^{134}I$ , ${}^{135}{Xe}$ , and ${}^{136}{Cs}$ . Charge distributions and most probable charges are deduced and compared to the unchanged charge distribution hypothesis. Fragment shell effects are discussed. In addition the isomeric ratios ${}^{126}{Sb}^{g}$ - ${}^{126}{Sb}^{m}$ , ${}^{128}{Sb (9 h)}$ - ${}^{128}{Sb (10 m i n)}$ , and ${}^{131}{Te}^{g}$ - ${}^{131}{Te}^{m}$ for the photofission of ${}^{235}U$ and ${}^{128}{Sb (9 h)}$ - ${}^{128}{Sb (10 m i n)}$ and ${}^{131}{Te}^{g}$ - ${}^{131}{Te}^{m}$ for the photofission of ${}^{238}U$ are determined and discussed.

NUCLEAR REACTIONS, FISSION ${}^{235, 238}U (γ, F)$ , $E_{γ max} = 25$ MeV; measured: fragment $γ$ -ray spectra; deduced: mass distributions, most probable charges, isomeric ratios.

Interaction of 28-GeV protons with thorium: Study of charge dispersions and mass yields

Y. Y. Chu, E. M. Franz, G. Friedlander, and P. J. Karol

Phys. Rev. C 14, 1068 (1976) - Published 1 September, 1976

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Yields of 53 nuclides ranging from ${}^{43}{Sc}$ to ${}^{173}{Hf}$ (with the majority in the rare-earth region) produced in the interaction of 28-GeV protons with thorium have been measured. Cumulative yields for neutron-rich nuclides with $A \geq 140$ exhibit similar mass dependence as those in low-energy fission. Charge dispersion curves for $A = 146$ and $A = 170$ have been constructed based on independent and cumulative yields measured in this work for these masses and the published data on cesium isotopes. Total isobaric yields for 18 mass numbers were evaluated from results obtained in this study and earlier investigations. The overall shape of the mass-yield curve is thus determined. The hump of the mass-yield curve in the middle $50 \leq A \leq 150$ can be attributed mainly to binary fission but the broad background underneath probably cannot be accounted for by spallation alone. The charge dispersion curves and the mass-yield curve for thorium are qualitatively similar to those for uranium. However, the neutron-rich cumulative yields are 3-5 times smaller in thorium than in uranium targets; the fission peak from thorium is shifted to lower mass and the yields are shifted slightly toward higher neutron deficiency when compared with the yields from uranium.

NUCLEAR REACTIONS, FISSION ${}^{232}{Th} (p, f)$ , $E_{p} = 28$ GeV; measured $σ (A, Z)$ , 53 products ${}^{43}{Sc}$ - ${}^{173}{Hf}$ ; deduced charge dispersion curves and mass-yield curve. mass, chemically separated samples.

Multiple-scattering and nucleon-recoil effects in pion production by nucleons on nuclei

Kuo-Ho Yang, Barry R. Holstein, Morton M. Sternheim, and D. A. Sparrow

Phys. Rev. C 14, 1083 (1976) - Published 1 September, 1976

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We consider multiple-scattering and nucleon-recoil effects in the production of charged pions by nucleons incident on complex nuclei at intermediate energies. We find that the general features of the results are similar to those obtained earlier with a simpler semiclassical model. The inclusion of nucleon recoil increases the number of low energy pions but not enough to explain the observed $π^{-}$ data.

NUCLEAR REACTIONS ${}^{208}{Pb} (p, π^{\pm}) X$ . Comparison of semiclassical models. Effects of multiple scattering, nucleon recoil.

Effective pion-nucleon interaction in nuclear matter

L. S. Celenza, L. C. Liu, W. Nutt, and C. M. Shakin

Phys. Rev. C 14, 1090 (1976) - Published 1 September, 1976

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We discuss the modification of the interaction between a pion and a nucleon in the presence of an infinite medium of nucleons (nuclear matter). The theory presented here is covariant and is relevant to the calculation of the pion-nucleus optical potential. The specific effects considered are the modifications of the nucleon propagator due to the Pauli principle and the modification of the pion and nucleon propagators due to collisions with nucleons of the medium. We also discuss in detail the pion self-energy in the medium, paying close attention to off-shell effects. These latter effects are particularly important because of the rapid variation with energy of the fundamental pion-nucleon interaction. Numerical results are presented, the main feature being the appearance of a significant damping width for the (3, 3) resonance.

NUCLEAR REACTIONS Effective $π - N$ interaction, propagator modifications in nuclear matter.

Effective-channel analysis of proton-helium scattering at medium energies. III

D. W. Rule and Yukap Hahn

Phys. Rev. C 14, 1102 (1976) - Published 1 September, 1976

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Elastic scattering of protons by helium targets are analyzed using the effective-channel approach at incident laboratory energies of 590 and 720 MeV. The helium nuclear form factor obtained from the electron scattering is used in the direct elastic channel to improve the large angle behavior of the cross section. Lack of reliable $p - p$ and $p - n$ data at these energy ranges severely limits the accurate determination of the input parameters, and makes the present analysis less definite than in the 1 GeV case studied earlier. However, the qualitative features of the result of the calculation show that the effect of the inelastic channels specifically associated with the excitations of the target system during the collision is large at large angles, and that the calculated cross sections are somewhat lower than the experimental data. The Coulomb effect is also studied at the 590 MeV case and found to be small.

NUCLEAR REACTIONS ${}^{4}{He} (p, p)$ elastic cross sections at 0.59, 0.72, and 1.00 GeV, calculated by the effective-channel approach.

Cross sections for production of stable and long-lived nuclides by high energy spallation of iron; cosmic ray implications

Claude Perron

Phys. Rev. C 14, 1108 (1976) - Published 1 September, 1976

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The cross sections for production of the stable and long-lived isotopes of Be, Sc, V, Cr, and Mn by proton spallation of Fe have been measured at 600 MeV and 21 GeV. The experimental method involves the contamination free separation of the spallation products from ultrapure iron targets and the mass spectrometric determination of their isotopic ratios. To derive absolute cross sections, radioactive isotopes are used as references. For this purpose, the cross sections of a few radioactive isotopes have been measured at 21 GeV by $γ$ -ray spectrometry. The results are compared with the values obtained by means of semiempirical formulas. The overall agreement is good but the cross sections for formation of manganese isotopes are found to be significantly higher than predicted. The implications of the results for path-length distribution and source abundances of cosmic ray nuclei with $21 \leq Z \leq 26$ are discussed. Calculated cosmic ray isotopic distributions are presented for some elements, which illustrate the potential resources of electron capture isotopes.

NUCLEAR REACTIONS $Fe (p, x) {}^{10}{Be}$ , ${}^{45}{Sc}$ , ${}^{49, 50, 51}V$ , ${}^{50, 52, 53, 54}{Cr}$ , ${}^{53, 55}{Mn}$ , $E = 600$ MeV; $Fe (p, x) {}^{7, 9, 10}{Be}$ , ${}^{22}{Na}$ , ${}^{45, 46}{Sc}$ , ${}^{48, 49, 50, 51}V$ , ${}^{50, 51, 52, 53, 54}{Cr}$ , ${}^{54}{Mn}$ , ${}^{56}{Co}$ , $E = 21$ GeV; measured $σ' s$ ; deduced cosmic ray abundances; natural target.

Nuclear reactions of ${}^{197}{Au}$ with 11.5- and 300-GeV protons

S. B. Kaufman, M. W. Weisfield, E. P. Steinberg, B. D. Wilkins, and D. Henderson

Phys. Rev. C 14, 1121 (1976) - Published 1 September, 1976

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The formation cross sections of more than 60 nuclides produced in the reaction of 11.5- and 300-GeV protons with ${}^{197}{Au}$ were measured. Most of the measurements were done by direct counting of the target with calibrated Ge(Li) $γ$ -ray spectrometers and spectral analysis with computer programs. In addition, chemical separations of osmium and gold fractions permitted the assay of nuclides which could not be resolved in the unseparated targets. The cross-section ratio at the two energies $\frac{σ_{300}}{σ_{11.5}}$ was within 20% of unity for all nuclides studied, which ranged in mass from ${}^{22}{Na}$ to ${}^{196}{Au}$ . This is interpreted as showing that the spectrum of excitation energies left in the nucleus is nearly independent of bombarding energy above ∼ 10 GeV. The small cross-section changes observed are shown to be continuations of trends seen previously at lower energies. Charge dispersion curves were estimated with the aid of an empirical formula, and a mass-yield curve was constructed.

NUCLEAR REACTIONS ${}^{197}{Au}$ + 11.5-, 300-GeV protons; measured $σ$ for formation of 63 nuclides from ${}^{22}{Na}$ to ${}^{196}{Au}$ ; estimated charge dispersions and mass yield curve.

RADIO ACTIVITY Measured $T_{\frac{1}{2}}$ of ${}^{182}{Os}$ , ${}^{183}{Os}$ , ${}^{183}{Os}^{m}$ .

Quasideuteron mechanism and the photodisintegration of ${}^{4}{He}$ at intermediate energies

C. T. Noguchi and F. Prats

Phys. Rev. C 14, 1133 (1976) - Published 1 September, 1976

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The ${}^{4}{He} (γ, p) {}^{3}H$ and ${}^{4}{He} (γ, n) {}^{3}{He}$ reactions from $E_{γ} ≳ 60$ MeV to $E_{γ} ≲ 170$ MeV are considered, along with the ${}^{4}{He} (γ, p n d)$ reaction from threshold up to intermediate energies. The absorption of photons in the intermediate energy range up to pion threshold is expected to occur predominantly via the quasideuteron mechanism as is indicated from the reaction ${}^{4}{He} (γ, p n d)$ . For the ( $γ, p n d$ ) amplitude, the breakup of ${}^{4}{He}$ into a deuteron and quasideuteron is calculated using a ${}^{4}{He}$ Gaussian ground-state wave function fitted to the form factor, a quasideuteron $S$ -wave scattered state, and a deuteron effective range wave function. The photobreakup of the quasideuteron can be expressed in terms of the amplitude for the photobreakup of the deuteron as shown by Levinger. The photoamplitude for the ( $γ, p n d$ ) reaction is used to obtain the photoamplitude for the ( $γ, n$ ) and ( $γ, p$ ) reactions. The contribution to the ( $γ, p$ ) and ( $γ, n$ ) reactions from the quasideuteron mechanism is calculated as a rescattering of a nucleon-deuteron pair to form a triton. For both nucleon-triton reactions, this yields angular distributions with forward peaking in agreement with the forward asymmetry obtained experimentally. The cross section at intermediate energy appears to be dominated by the quasideuteron effect. Finally, the alternative quasideuteron calculation using nucleon-nucleon short-range correlations is shown to be equivalent to the present quasideuteron calculation.

NUCLEAR REACTIONS ${}^{4}{He} (γ, p n d)$ , ${}^{4}{He} (γ, p)$ , ${}^{4}{He} (γ, n)$ ; calculated $σ (E_{γ})$ , $\frac{d σ}{{d Ω}_{N}}$ ( $E_{γ} = 60 - 170$ MeV), quasideuteron mechanism.

Levels of ${}^{129}I$ populated in the decay of ${}^{129}{Te}^{m}$ and ${}^{129}{Te}^{g}$

L. G. Mann, W. B. Walters, and R. A. Meyer

Phys. Rev. C 14, 1141 (1976) - Published 1 September, 1976

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We have studied the decay of 33-day ${}^{129}{Te}^{m}$ and 70-min ${}^{129}{Te}^{g}$ with high resolution Ge(Li) detectors used both singly and in coincidence. Sources of ${}^{129}{Te}^{m}$ and ${}^{129}{Te}^{g}$ in equilibrium were used as well as sources of ${}^{129}{Te}^{g}$ containing less than 0.0003 parts ${}^{129}{Te}^{m}$ activity. Fifty $γ$ rays resulting from ${}^{129}{Te}^{g}$ decay and 39 $γ$ rays from ${}^{129}{Te}^{m}$ decay have been assigned to levels in ${}^{129}I$ . This work establishes new levels in ${}^{129}I$ at 1047.44 ( ${3 / 2}^{+}$ ), 1203.7 ( ${7 / 2}^{+}$ ), 1209.9 ( ${1 / 2}^{+}$ ), and 1282.00 ( ${7 / 2}^{+}$ ) keV ( $J^{π}$ in parentheses). In conjunction with recent ( ${}^{3}{He}, d$ ) and angular distribution work several other new or more reliable spin-parity assignments can be made as follows: 845 ( ${9 / 2}^{+}$ ), 1112 ( ${5 / 2}^{+}$ ), 1261 ( ${5 / 2}^{+}$ ), 1292 ( ${3 / 2}^{+}$ ), and 1401 ( ${11 / 2}^{-}$ ). The data are discussed in terms of the particle or quasiparticle phonon model and the three-particle cluster model.

RADIOACTIVITY ${}^{129}{Te}$ [from ${}^{128}{Te}^{m} (n, γ)$ ]; measured $E_{γ}$ , $I_{γ}$ , $γ γ$ coin; deduced $log ft$ . ${}^{129}I$ deduced levels $E$ , $J$ , $Π$ ; $B (E 2)$ . Ge(Li) detectors, enriched ${}^{128}{Te}$ targets.

Levels of odd-mass Xe populated in the beta decay of ${}^{129}{Cs}$ , and ${}^{133}I$

R. A. Meyer, F. F. Momyer, J. H. Landrum, E. A. Henry, R. P. Yaffe, and W. B. Walters

Phys. Rev. C 14, 1152 (1976) - Published 1 September, 1976

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The decay schemes of ${}^{129}{Cs}$ and ${}^{133}I$ have been studied in order to extend the detailed level properties of odd-mass Xe. For ${}^{129}{Cs}$ , decay levels in ${}^{129}{Xe}$ are identified at ( $J^{π}$ values in parentheses) ground state ( $({\frac{1}{2}}^{+})$ ), $39.57 ({\frac{3}{2}}^{+})$ , $236.14 ({\frac{11}{2}}^{-})$ , $({\frac{3}{2}}^{+})$ , $321.70 ({\frac{5}{2}}^{+})$ , $411.49 ({\frac{1}{2}}^{+})$ , $572.67 ({\frac{5}{2}}^{+})$ , $588.55 ({\frac{3}{2}}^{+})$ , $624.32 ({\frac{7}{2}}^{+})$ , $904.31 ({\frac{1}{2}}^{+})$ , and 946.03 keV ( $({\frac{3}{2}}^{+})$ ); for ${}^{133}I$ , decay levels in ${}^{133}{Xe}$ are identified at ground state ( $({\frac{3}{2}}^{+})$ ), $233.22 ({\frac{11}{2}}^{-})$ , $262.70 ({\frac{1}{2}}^{+})$ , $529.87 ({\frac{5}{2}}^{+})$ , $680.24 ({\frac{3}{2}}^{+})$ , $743.75 ({\frac{9}{2}}^{-}, {\frac{7}{2}}^{-})$ , $875.32 ({\frac{7}{2}}^{+})$ , $911.46 ({\frac{3}{2}}^{+})$ , $1052.29 ({\frac{5}{2}}^{+})$ , $1236.44 ({\frac{7}{2}}^{+})$ , $1298.22 ({\frac{5}{2}}^{+})$ , $1350.32 ({\frac{5}{2}}^{+})$ , $1386.15 ({\frac{7}{2}}^{+})$ , and 1589.92 keV ( $({\frac{7}{2}}^{+}, {\frac{5}{2}}^{+})$ ). Gas chromatography techniques were used to determine a branching ratio of (2.88 ± 0.02)% of all ${}^{133}I$ decays populating the ${}^{133}{Xe} {\frac{11}{2}}^{-}$ isomer. These levels and their properties are compared with other odd-mass Xe nuclei and their level properties.

RADIOACTIVITY ${}^{129}{Cs}$ (mass separated) ${}^{133}I$ (chemically isolated from fission) measured $E_{γ}$ , $I_{γ}$ , $γ - γ$ coin; deduced $log ft$ . ${}^{129}{Xe}$ and ${}^{133}{Xe}$ deduced levels, $J$ , $π$ .

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Highly excited states in ${}^{6}{Li}$ by the reaction ${}^{9}{Be} (p, α) {}^{6}{Li}$

Extraction of single-particle energies from experiment

Excitation of the giant dipole resonance in ${}^{12}C (π, π^{'}) {}^{12}C^{*}$

Exact finite-range CCBA calculations for the reaction ${}^{16}O (d, {}^{6}{Li}) {}^{12}C$ at $E_{d} = 35$ MeV

Unnatural parity levels at high excitation in ${}^{20}{Ne}$

Lifetimes of yrast states in ${}^{51}{Ti}$ , ${}^{52}{Ti}$ , and ${}^{52}V$

High-spin states and neutron-hole influence in ${}^{209}{At}$

Inelastic effects in heavy-ion one-neutron transfer on ${}^{26}{Mg}$

Reactions of ${}^{40}{Ar}$ with ${}^{160}{Dy}$ , ${}^{164}{Dy}$ , and ${}^{174}{Yb}$

Application of Austern-Blair theory to the interference between Coulomb and nuclear excitation in the inelastic scattering of heavy ions

Product yields for the photofission of ${}^{235}U$ and ${}^{238}U$ with 25-MeV bremsstrahlung

Interaction of 28-GeV protons with thorium: Study of charge dispersions and mass yields

Multiple-scattering and nucleon-recoil effects in pion production by nucleons on nuclei

Effective pion-nucleon interaction in nuclear matter

Effective-channel analysis of proton-helium scattering at medium energies. III

Cross sections for production of stable and long-lived nuclides by high energy spallation of iron; cosmic ray implications

Nuclear reactions of ${}^{197}{Au}$ with 11.5- and 300-GeV protons

Quasideuteron mechanism and the photodisintegration of ${}^{4}{He}$ at intermediate energies

Levels of ${}^{129}I$ populated in the decay of ${}^{129}{Te}^{m}$ and ${}^{129}{Te}^{g}$

Levels of odd-mass Xe populated in the beta decay of ${}^{129}{Cs}$ , and ${}^{133}I$

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