Recent Articles

Production of Ca, Ga, and Br nuclei having angular momenta equal to or greater than the calculated liquid drop limit

M. N. Namboodiri, E. T. Chulick, J. B. Natowitz, and R. A. Kenefick

Phys. Rev. C 11, 401 (1975) - Published 1 February, 1975

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A semiconductor detector telescope has been used to detect heavy recoil nuclei produced in the reactions of 157 and 262 MeV ${}^{14}N$ projectiles with ${}^{27}{Al}$ , Cr, and Ni target nuclei. Cross sections have been determined for the production of heavy recoiling compound nucleus residues. The limiting angular momenta which have been derived from these cross sections indicate the production of nonfissioning compound nuclei with angular momenta which equal or exceed the critical limit calculated using the liquid drop model. A comparison of the data with limits calculated using a reaction potential model recently proposed by Bass suggests that a picture based on dynamic restrictions to the fusion process provides a reasonable explanation of the results. However, the saturation limit predicted by the Bass model has not been observed.

NUCLEAR REACTIONS ${}^{14}N$ + ${}^{27}{Al}$ , ${}^{14}N$ +Cr, ${}^{14}N$ +Ni, $E = 157 and 262$ MeV, measured $σ (E)$ for compound nucleus residues. Deduced limiting $J$ for production of nonfissioning compound nucleus.

Production of ${}^{6}{Li}$ , ${}^{9}{Be}$ , and ${}^{10}B$ in $p$ + ${}^{13}C$ reactions at low energies

D. L. Oberg, D. Bodansky, D. Chamberlin, and W. W. Jacobs

Phys. Rev. C 11, 410 (1975) - Published 1 February, 1975

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Cross sections have been measured for the production of ${}^{6}{Li}$ , ${}^{9}{Be}$ , and ${}^{10}B$ in proton reactions on ${}^{13}C$ , at energies extending from threshold to 18 MeV. The reaction products were identified by time-of-flight techniques, and total cross sections were determined by integrating over the measured angular distributions. Although the typical abundance of ${}^{13}C$ in nature is small compared to that of ${}^{12}C$ , ${}^{14}N$ , or ${}^{16}O$ , the ${}^{13}C$ reactions may have a significant role in the production of the light elements because of their low $Q$ values. Even for a ${}^{13}C$ / ${}^{12}C$ ratio as low as the terrestrial ratio of 0.01, the inclusion of ${}^{13}C$ contributions is found to reduce appreciably the $\frac{7}{6}$ , $\frac{11}{10}$ , and Li/Be abundance ratios calculated for interactions at low energies between protons and a representative mixture of C, N, and O. Over-all, this reduction brings the abundance ratios calculated at proton energies below 25 MeV closer to the observed solar system ratios.

NUCLEAR REACTIONS ${}^{15}C (p, α)$ , $E = 5 - 18$ MeV; ${}^{13}C (p, 2 α)$ , $E = 10 - 18$ MeV; ${}^{13}C (p, p α)$ , $E = 13 - 18$ MeV; measured $σ (θ)$ , $σ (E)$ , $σ$ . Astrophysical production of LiBeB.

( $p, pd$ ) reaction on ${}^{6}{Li}$ at 590 MeV for high recoil momenta

P. Kitching, W. C. Olsen, H. S. Sherif, W. Dollhopf, C. Lunke, C. F. Perdrisat, J. R. Priest, and W. K. Roberts

Phys. Rev. C 11, 420 (1975) - Published 1 February, 1975

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In a kinematically complete experiment with 590 MeV protons, the reaction ${}^{6}{Li} (p, p d)$ has been studied for recoil momenta up to 240 MeV/c. When the results are interpreted in terms of the plane wave impulse approximation, it is found that the number of $α - d$ clusters in ${}^{6}{Li}$ is 0.78±0.10. If the momentum distribution is fitted with a Gaussian of the form $e^{- {(\frac{q}{q_{0}})}^{2}}$ , the best fit is obtained with a width parameter $q_{0} = 73 \pm 1.6$ MeV/c, in agreement with our previous results at lower recoil momenta. Several model wave functions were used to calculate the momentum distribution. Qualitative agreement is obtained, with the best fit being provided by the Eckart type cluster wave function.

NUCLEAR REACTIONS ${}^{6}{Li} (p, p d)$ , $E = 590$ MeV, measured $d^{3} σ$ , determined momentum distribution and $n_{α - d}$ , compared with calculated distributions.

Why the Hauser-Feshbach formula works

P. A. Moldauer

Phys. Rev. C 11, 426 (1975) - Published 1 February, 1975

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It is shown that flux conservation requires substantial channel-channel correlations of resonance amplitudes. These, together with the effects of level-level correlations and other terms conspire to cancel the large additive corrections to the Hauser-Feshbach formula for the fluctuation cross section. The remaining multiplicative corrections become negligible for nonelastic cross sections when many channels are open. In other cases, approximation formulas provide estimates that are adequate for most purposes. However, the Bohr independence hypothesis is not always satisfied when fewer than about 20 channels are open. The cross section correlation width is shown to differ markedly from the average width. The use of the former for estimating the Hauser-Feshbach denominator is found to be justified. All of these results are verified by means of statistical model calculations of resonance parameters and of cross sections.

Nucleon-nucleon correlations and the pion-nucleus interaction

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

Phys. Rev. C 11, 437 (1975) - Published 1 February, 1975

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The scattering of pions from a correlated pair of nucleons is studied in a recently proposed covariant theory of pion-nucleus scattering. In this theory the off-shell effects arising from the correlations can be treated unambiguously. In the covariant theory, "off-shell effects" refers to both the usual off-shell effects known from conventional nonrelativistic multiple-scattering theories and to off-mass-shell features particular to the relativistic theories. It is shown that these effects, absent in a "fixed-scatterer approximation," require knowledge of the fundamental pion-nucleon scattering amplitudes in regions which are not readily parametrized using on-shell scattering data. In a simplified model we illustrate this point by comparing our dynamical approach to the corresponding fixed-scatterer analysis. We conclude that any reliable estimate of correlation effects in pion-nucleus interaction requires that serious consideration be given to the off-shell aspects of the dynamics.

Coupled-channels calculation of the analyzing power in the reaction ${}^{15}N (p, γ_{0}) {}^{16}O$ using polarized protons

K. Ramavataram, C. L. Rao, and S. Ramavataram

Phys. Rev. C 11, 450 (1975) - Published 1 February, 1975

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The excitation function of the analyzing power $A (θ)$ in the reaction ${}^{15}N (p, γ_{0}) {}^{16}O$ induced by polarized protons is calculated by the coupled-channels theory and compared with experiment. The theory predicts (i) the minimum in the value of $A (45 °)$ corresponding to the observed minimum at 7.8 MeV proton energy and (ii) the sign and magnitude of $A (45 °)$ in the region of the giant dipole resonance in ${}^{16}O$ . This theoretical analysis shows that the structure in $A (45 °)$ can be directly related to the configuration of the $1^{-}$ states below the giant dipole resonance.

NUCLEAR REACTIONS ${}^{15}N (p, γ_{0}) {}^{16}O$ ; polarized protons $E = 4 - 12$ MeV. Calculated $σ (E)$ and the analyzing power near the giant dipole resonance (GDR) by the coupled-channels method and compared with experiment. Deduced the configurational structure of $1^{-}$ states below the giant dipole resonance.

Neutron resonance spectroscopy: Argon

H. I. Liou, J. Rainwater, G. Hacken, and U. N. Singh

Phys. Rev. C 11, 457 (1975) - Published 1 February, 1975

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Results are presented of the high resolution measurements of the neutron total cross section of natural argon to 580 keV. Of the 24 levels observed in ${}^{40}{Ar}$ , 6 are assigned to be $l = 0, and 18$ to be $l = 1$ . Resonance parameters were obtained using area and $R$ -matrix analyses for $s$ levels, and area analysis including the Doppler broadening effect for $p$ levels. The $s$ and $p$ strength functions and average level spacings for ${}^{40}{Ar}$ were $10 {}^{4}S_{0} = {0.91}_{- 0.37}^{+ 0.77}$ , $10 {}^{4}S_{1} = {0.33}_{- 0.09}^{+ 0.14}$ , $〈 D_{0} 〉 = (87_{- 11}^{+ 13})$ keV, and $〈 D_{1} 〉 = (24_{- 4}^{+ 5})$ keV.

NUCLEAR REACTIONS ${}^{40}{Ar} (n, n)$ , ( $n, γ$ ), $E = 1 - 580$ keV; measured $σ_{t} (E)$ ; deduced $E_{0}$ , $g Γ_{n}$ , $l$ , $J$ , $S_{0}$ , $S_{1}$ , $〈 D_{0} 〉$ , $〈 D_{1} 〉$ .

Neutron resonance spectroscopy: The separated isotopes of Dy

H. I. Liou, G. Hacken, J. Rainwater, and U. N. Singh

Phys. Rev. C 11, 462 (1975) - Published 1 February, 1975

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Results are given for the neutron resonance parameters of the Dy isotopes (160 to 164) based on 202.05 m transmission and 39.536 m capture self-indication flight path time of flight measurements using the Columbia-Nevis synchrocyclotron. The $A = 161 to 164$ samples were ∼ 92 to 98% enriched. The ${}^{160}{Dy}$ sample was 69.5% enriched. We give $E_{0}$ and $(g) Γ_{n}^{0}$ values for: ${}^{160}{Dy}$ —64 levels to 2 keV; ${}^{161}{Dy}$ —251 levels to 1 keV; ${}^{162}{Dy}$ —142 levels to 16 keV; ${}^{163}{Dy}$ —114 levels to 1 keV; ${}^{164}{Dy}$ —116 levels to 21 keV. The $〈 Γ_{γ} 〉$ values and (numbers) of $Γ_{γ}$ values were 108 meV (9), 112 meV (26), 112 meV (16), 113 meV (39), and 114 meV (5), respectively. A shape fit to the strong asymmetric level at 147 eV in ${}^{164}{Dy}$ gave $R^{'} = 7.5$ fm. The $l = 0$ strength functions, $10 {}^{4}S_{0}$ , are (2.00±0.36), (1.73±0.17), (1.88±0.25), (2.02±0.30), and (1.70±0.25), respectively. Using our threshold sensitivities for level detection vs $E$ , and various statistical tests, indicates the following numbers of missed $s$ levels to the $E_{max}$ where most $s$ levels were seen as: ${}^{160}{Dy}$ —2 to 900 eV; ${}^{161}{Dy}$ —5 to 140 eV; ${}^{162}{Dy}$ —2 to 3 keV and 6 to 4.5 keV; ${}^{163}{Dy}$ —2 to 220 eV; and ${}^{164}{Dy}$ —2 to 5 keV. No $p$ levels were included for 160, 161, 163, but a few were present for 162 and 164, giving $10 {}^{4}S_{1} = (1.1 \pm 0.4) ({}^{162}{Dy}) and (1.3 \pm 0.3) ({}^{164}{Dy})$ . Various statistical tests suggest where the missed $s$ levels should be located to give good agreement with the tests, giving $〈 D_{0} 〉 = (27.3 \pm 1.7), (2.67 \pm 0.13), (64.6 \pm 1.9), (6.85 \pm 0.54), and (147 \pm 9)$ eV, respectively.

NUCLEAR REACTIONS ${}^{160, 161, 162, 163, 164}{Dy}$ ( $n, n$ ), ( $n, γ$ ), $E = 1$ eV-few keV; measured $σ_{t} (E)$ ; deduced $E_{o}$ , $g Γ_{n}^{o}$ , $Γ_{γ}$ , $S_{0}$ , $〈 D_{0} 〉$ , $S_{1}$ ; various statistical tests.

Where is the $g_{\frac{9}{2}}$ proton state in ${}^{87}{Rb}$ ?

L. R. Medsker, H. T. Fortune, S. C. Headley, and J. N. Bishop

Phys. Rev. C 11, 474 (1975) - Published 1 February, 1975

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A strong $l_{p} = 4$ transition [with $(2 J + 1) C^{2} S = 10.3 \pm 1.5$ ] observed in the ${}^{86}{Kr} ({}^{3}{He}, d) {}^{87}{Rb}$ reaction establishes the 1579-keV state as the $g_{\frac{9}{2}}$ proton single-particle state and resolves a longstanding discrepancy.

NUCLEAR REACTIONS ${}^{86}{Kr} ({}^{3}{He}, d)$ , $E = 18$ MeV; enriched target; measured $σ (E_{d}, θ)$ ; deduced 1579-keV level, $l$ , $G_{lj}$ .

${}^{40, 48}{Ca} (d, p)$ reactions near the Coulomb barrier: Comparison of coupled-channel and distorted-wave Born-approximation calculations

Shankar Mukherjee and Radhey Shyam

Phys. Rev. C 11, 476 (1975) - Published 1 February, 1975

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The ( $d, p$ ) reactions on ${}^{40}{Ca}$ and ${}^{48}{Ca}$ targets for incident deuteron energies near the Coulomb barrier (2-5.5 MeV) are studied by a coupled-channel (CC) method in which the $Δ l = 1$ stripping channel has been coupled to the incident deuteron channel. The method employs a set of energy independent optical potential parameters and predicts differential cross sections and polarizations in both the incident deuteron channel and the stripping channel. The results are compared with the measured values and those obtained from the distorted-wave Born-approximation calculations. It is found that the effect of the coupling is reasonably large even in this low energy region. There is an indication that the CC predictions for ${}^{40}{Ca}$ targets will improve with the inclusion of the coupling of the $Δ l = 3$ stripping channel. It is also suggested that some portion of the $j$ dependence in ( $d, p$ ) angular distributions may be simulated by the coupling of the stripping channel.

NUCLEAR REACTIONS ${}^{40, 48}{Ca} (d, d)$ , ( $d, p$ ), $E = 2.0 - 5.5$ MeV; calculated $σ (E, θ)$ , $T_{11} (θ)$ , coupled-channel model, DWBA.

High resolution ( $p, p^{'}$ ) on ${}^{207}{Pb}$ and ${}^{209}{Bi}$

W. T. Wagner, G. M. Crawley, and G. R. Hammerstein

Phys. Rev. C 11, 486 (1975) - Published 1 February, 1975

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The inelastic scattering of protons from ${}^{207}{Pb}$ and ${}^{209}{Bi}$ has been measured with energy resolution on the order of $\frac{1}{5000}$ . Many states were observed and a number of weak coupling multiplets were identified. Use of the collective model and weak coupling theory enabled spin and parity assignments to be made. Calculations for the observed single particle states with noncentral forces and with core polarization are presented.

NUCLEAR REACTIONS ${}^{207}{Pb} (p, p^{'})$ , ${}^{209}{Bi} (p, p^{'})$ , $E = 35$ MeV; measured $σ (θ)$ , $θ = 10 - 100 °$ . Deduced $L$ , $β_{L}$ ; microscopic DWBA analysis.

Consequences of fission deexcitation of compound nuclei formed in heavy-ion reactions

F. Plasil and M. Blann

Phys. Rev. C 11, 508 (1975) - Published 1 February, 1975

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Restrictions on cross sections of compound nuclei surviving fission during the dexcitation process are investigated for a variety of heavy-ion projectile-target combinations. Calculations are performed within the framework of the Bohr-Wheeler model using angular-momentum-dependent fission barriers calculated from the rotating liquid drop model of Cohen, Plasil, and Swiatecki. It is shown that fission severely limits the cross sections of evaporation residue products at higher bombarding energies, that the critical angular momenta of such a model slowly increase with increasing bombarding energy, and that these critical angular momenta are very much lower than the values at which the fission barrier is thought to disappear. Calculated cross sections are in reasonable agreement with several experimental excitation functions. Experimental results are also compared with limits on fusion cross sections resulting from entrance conditions and comparisons are made between the consequences of the two types of models—entrance condition limits and fission-imposed limits on evaporation residue products.

NUCLEAR REACTIONS Calculated evaporation residue $σ (E)$ . HI projectiles ${}^{11}B$ to ${}^{84}{Kr}$ , targets ${}^{10}B$ to ${}^{165}{Ho}$ , compound nuclei ${}^{43}{Sc}$ to ${}^{211}{Ac}$ , $E = 3.5 - 10.5$ MeV/nucleon. Deduced critical $J$ .

Simple relation between the asymmetry and longitudinal polarization of the recoil nucleus in muon capture

P. R. Subramanian and V. Devanathan

Phys. Rev. C 11, 520 (1975) - Published 1 February, 1975

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An interesting relation $α - 2 P_{L} = 1$ is obtained between the asymmetry parameter $α$ and the longitudinal polarization $P_{L}$ of the recoil nucleus in the reaction $μ^{-} + A ({J_{i}}^{π_{i}}) \to B ({J_{f}}^{π_{f}}) + ν_{μ}$ , in which the initial nuclear spin is zero. It is shown algebraically that this relation is independent of both the nuclear structure and the values of the coupling constants of the muon capture interaction with or without inclusion of second class current terms.

Near-threshold resonance neutrons from ${}^{63}{Cu} (p, n_{0}) {}^{63}{Zn}$ and ${}^{68}{Zn} (p, n_{0}) {}^{68}{Ga}$

H. W. Lefevre and D. W. Kneff

Phys. Rev. C 11, 524 (1975) - Published 1 February, 1975

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We report the observation and study of several narrow resonances near threshold in the reactions ${}^{63}{Cu} (p, n_{0}) {}^{63}{Zn}$ and ${}^{68}{Zn} (p, n_{0}) {}^{68}{Ga}$ . The first resonance above threshold in ${}^{63}{Cu} (p, n_{0}) {}^{63}{Zn}$ occurs at a proton energy 299 eV above threshold and has a c.m. width of 25±10 eV. That for ${}^{68}{Zn} (p, n_{0}) {}^{68}{Ga}$ occurs at a proton energy 622 eV above threshold and has a c.m. width of 8±1 eV.

NUCLEAR REACTIONS ${}^{63}{Cu} (p, n_{0})$ , ${}^{68}{Zn} (p, n_{0})$ ;; near threshold; measured neutron time of flight, ${}^{6}{Li}$ glass scintillator, deduced resonance widths, and cross sections.

Nuclear levels of ${}^{239}{Np}$ excited by the ( ${}^{3}{He}$ , $d$ ) and ( $α, t$ ) reactions

T. von Egidy, Th. W. Elze, and J. R. Huizenga

Phys. Rev. C 11, 529 (1975) - Published 1 February, 1975

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The single proton transfer reactions ${}^{238}U ({}^{3}{He}, d) {}^{239}{Np}$ and ${}^{238}U (α, t) {}^{239}{Np}$ have been measured with 28.5-MeV ${}^{3}{He}$ and $α$ particles, respectively. The experimental cross sections are compared with theoretical cross sections in order to determine $l$ values and to construct a level scheme of ${}^{239}{Np}$ . The configurations $\frac{5}{2^{+}} [642 ↑]$ , $\frac{5}{2^{-}} [523 ↓]$ , $½^{-}$ [530], and $\frac{3}{2^{-}} [521 ↑]$ are identified. Levels of the four additional rotational bands $½^{+}$ [400], $\frac{3}{2^{+}} [651 ↑]$ , $\frac{7}{2^{+}} [633 ↑]$ , and $\frac{7}{2^{-}} [514 ↓]$ are assigned tentatively. A level scheme of ${}^{239}{Np}$ containing $γ$ rays following the $β$ decay of ${}^{239}U$ is presented also.

NUCLEAR REACTIONS ${}^{238}U ({}^{3}{He}, d)$ , ${}^{238}U (α, t)$ , $E = 28.5$ MeV; measured $σ (θ)$ . deduced $l$ values, Nilsson configurations, and level scheme of ${}^{239}{Np}$ .

Cross sections above 0.3 GeV for ( $p, 2 p$ ) reactions of ${}^{48}{Ti}$ and ${}^{74}{Ge}$

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

Phys. Rev. C 11, 541 (1975) - Published 1 February, 1975

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Cross sections for the ${}^{48}{Ti} (p, 2 p) {}^{47}{Sc}$ and the ${}^{74}{Ge} (p, 2 p) {}^{73}{Ga}$ reactions were measured from 0.3 to 4.6 GeV incident proton energy. A rise in cross section of (25 ± 3)% is observed for each reaction in the energy region from 0.3 to 1.0 GeV. The ( $p, 2 p$ ) cross sections for ${}^{48}{Ti}$ were found to be systematically about 30% larger than those for ${}^{74}{Ge}$ . Comparisons with four prior cases are made. The present results are compared to ( $p, 2 p$ ) cross section calculations up to 1.0 GeV based on a Monte Carlo intranuclear cascade-evaporation model. The model yields cross sections that are generally a factor of 2 greater than the experimental values.

NUCLEAR REACTIONS ${}^{46}{Ti} (p, 2 p)$ , ${}^{74}{Ge} (p, 2 p)$ $E = 0.3 - 4.6$ GeV, measured and calculated $σ (E)$ .

Level structure and $γ$ transitions in ${}^{202}{Hg}$ studied by the ( $n, γ$ ) reaction

D. Breitig, R. F. Casten, W. R. Kane, G. W. Cole, and J. A. Cizewski

Phys. Rev. C 11, 546 (1975) - Published 1 February, 1975

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Several ( $n, γ$ ) techniques at thermal and resonant neutron energies have been used to investigate the level scheme of ${}^{202}{Hg}$ . Low and high energy ( $n, γ$ ) spectra have been measured at the Brookhaven National Laboratory high flux beam reactor using Ge(Li) detectors. Two parameter coincidence spectra and $γ - γ$ angular correlation data were taken. Primary transitions from resonance capture in ${}^{201}{Hg}$ were studied with the fast chopper facility at BNL. The combination of these data led to the construction of a detailed level scheme up to about 2 MeV. Twenty-two excited states were found, most of which could be given spins or spin limits. As in ${}^{200}{Hg}$ a systematic behavior of the level population as a function of energy and spin was observed and could be used for spin assignments. Most of the levels, and in particular their $γ$ deexcitations, were not accurately known previously. Of special interest is the observation that the lowest excited $0^{+}$ state is at 1564 keV. Another $0^{+}$ state was discovered at 1643 keV. These findings shed new light on the "extra" $0^{+}$ state in ${}^{200}{Hg}$ at 1029 keV. The systematics of level energies and branching ratios in the Hg isotopes is treated and is found to be suggestive of significant nuclear structure differences as a function of neutron number. In particular, a comparison with model calculations for core-coupled states revealed extensive disagreements for ${}^{202}{Hg}$ , in contrast to the rather satisfactory comparison found in ${}^{200}{Hg}$ .

NUCLEAR REACTIONS ${}^{201}{Hg} (n, γ)$ , $E = thermal, 43, 70.9, and 210$ eV. Measured $E_{γ}$ , $I_{γ}$ , $γ - γ$ $coin (⊖)$ in ${}^{202}{Hg}$ . ${}^{202}{Hg}$ deduced levels, transitions, $J$ , $π$ .

Study of ${}^{249}{Bk}$ , ${}^{241}{Am}$ , and ${}^{231}{Pa}$ with proton transfer reactions

J. R. Erskine, G. Kyle, R. R. Chasman, and A. M. Friedman

Phys. Rev. C 11, 561 (1975) - Published 1 February, 1975

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Proton single-particle states have been studied in the isotopes ${}^{249}{Bk}$ , ${}^{241}{Am}$ , and ${}^{231}{Pa}$ . The reaction ( $α, t$ ) was utilized in the three studies. Additionally, the reaction ( ${}^{3}{He}$ , $d$ ) was used in the study of levels in ${}^{249}{Bk}$ . Many new levels were observed and some could be interpreted in terms of single-particle orbitals. Also several assignments previously made on the basis of radioactive decay studies were confirmed by the orbital signatures seen in the proton transfer spectra. Single-particle energies are extracted from the experimental data. Deformations of the nuclear central potential are deduced for ${}^{249}{Bk}$ and ${}^{241}{Am}$ . By use of the parameters of the central field for ${}^{249}{Bk}$ , the $f_{\frac{7}{2}} - f_{\frac{5}{2}}$ splitting is deduced for mass 250 at zero deformation and estimated for mass 300.

NUCLEAR REACTIONS ${}^{248}{Cm} ({}^{3}{He}, d)$ , ${}^{248}{Cm}$ , ${}^{240}{Pu}$ , ${}^{230}{Th} (α, t)$ $E = 29$ MeV; measured $E$ (excitation), $σ$ ; deduced orbitals, s.p. energies, deformations in ${}^{249}{Bk}$ , ${}^{241}{Am}$ , ${}^{231}{Pa}$ .

Scission-point parameters determined by light particle emission in fission of ${}^{252}{Cf}$

Avigdor Gavron

Phys. Rev. C 11, 580 (1975) - Published 1 February, 1975

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Trajectory calculations were performed in order to determine "scission-point" parameters which fit experimental data on light particle emission from ${}^{252}{Cf}$ . The uncertainty principle was invoked when determining the initial light particle momentum and position. Experimental ${}^{5}{He}$ data were fitted in order to provide an absolute time scale for particle emission. The results indicate that different light particles are fitted with different sets of parameters. None of these sets are consistent with the kinetic energy distribution in binary fission.

RADIOACTIVITY, FISSION ${}^{252}{Cf} (sf)$ ; trajectory calculations of light charged particle emission.

Population of levels in ${}^{199}{Hg}$ following ${}^{199}{Tl}$ decay and intermediate coupling calculations for ${}^{199}{Hg}$

G. J. Mathews, F. M. Bernthal, and J. D. Immele

Phys. Rev. C 11, 587 (1975) - Published 1 February, 1975

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The electron capture decay of ${}^{199}{Tl}$ to levels in ${}^{199}{Hg}$ has been reinvestigated. Twenty new transitions are assigned to the ${}^{199}{Tl}$ decay scheme and the population of two new levels in ${}^{199}{Hg}$ at 750.4 and 1221.2 keV is confirmed. A quasiparticle-phonon coupling model is applied to low-lying levels in ${}^{199}{Hg}$ . Good agreement with experiment is obtained for the eigenvalues, spectroscopic factors, and electromagnetic transition rates and moments by variation of the $f_{\frac{5}{2}}$ neutron energy and by introducing a phenomenological reduction factor in the coupling matrix element.

RADIOACTIVITY ${}^{199}{Tl}$ measured $E_{γ}$ , $I_{γ}$ , $γ - γ$ coin, deduced $log ft$ . ${}^{199}{Hg}$ deduced levels, $J$ , $π$ .

NUCLEAR STRUCTURE ${}^{199}{Hg}$ calculated levels, $J$ , $π$ , $S$ , $μ$ , $q$ , $B (E 2)$ , $B (M 1)$ , $δ$ , branching ratios. Quasiparticle-phonon coupling.

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Production of Ca, Ga, and Br nuclei having angular momenta equal to or greater than the calculated liquid drop limit

Production of ${}^{6}{Li}$ , ${}^{9}{Be}$ , and ${}^{10}B$ in $p$ + ${}^{13}C$ reactions at low energies

( $p, pd$ ) reaction on ${}^{6}{Li}$ at 590 MeV for high recoil momenta

Why the Hauser-Feshbach formula works

Nucleon-nucleon correlations and the pion-nucleus interaction

Coupled-channels calculation of the analyzing power in the reaction ${}^{15}N (p, γ_{0}) {}^{16}O$ using polarized protons

Neutron resonance spectroscopy: Argon

Neutron resonance spectroscopy: The separated isotopes of Dy

Where is the $g_{\frac{9}{2}}$ proton state in ${}^{87}{Rb}$ ?

${}^{40, 48}{Ca} (d, p)$ reactions near the Coulomb barrier: Comparison of coupled-channel and distorted-wave Born-approximation calculations

High resolution ( $p, p^{'}$ ) on ${}^{207}{Pb}$ and ${}^{209}{Bi}$

Consequences of fission deexcitation of compound nuclei formed in heavy-ion reactions

Simple relation between the asymmetry and longitudinal polarization of the recoil nucleus in muon capture

Near-threshold resonance neutrons from ${}^{63}{Cu} (p, n_{0}) {}^{63}{Zn}$ and ${}^{68}{Zn} (p, n_{0}) {}^{68}{Ga}$

Nuclear levels of ${}^{239}{Np}$ excited by the ( ${}^{3}{He}$ , $d$ ) and ( $α, t$ ) reactions

Cross sections above 0.3 GeV for ( $p, 2 p$ ) reactions of ${}^{48}{Ti}$ and ${}^{74}{Ge}$

Level structure and $γ$ transitions in ${}^{202}{Hg}$ studied by the ( $n, γ$ ) reaction

Study of ${}^{249}{Bk}$ , ${}^{241}{Am}$ , and ${}^{231}{Pa}$ with proton transfer reactions

Scission-point parameters determined by light particle emission in fission of ${}^{252}{Cf}$

Population of levels in ${}^{199}{Hg}$ following ${}^{199}{Tl}$ decay and intermediate coupling calculations for ${}^{199}{Hg}$

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