Recent Articles

Erratum: Consequences of isospin and other conserved quantum numbers for compound-nucleus reactions

D. Robson, A. Richter, and H. L. Harney

Phys. Rev. C 11, 1867 (1975) - Published 1 May, 1975

${}^{10}B (α, n_{0}) {}^{13}N$ and ${}^{10}B (α, p_{i}) {}^{13}C$ for $2 < E_{α} < 8$ MeV

Stephen J. Wilson

Phys. Rev. C 11, 1071 (1975) - Published 1 April, 1975

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We present simultaneously obtained data for the mirror reactions ${}^{10}B (α, n_{0}) {}^{13}N$ and ${}^{10}B (α, p_{0}) {}^{13}C$ and interpret the yield ratio with the formula of Barker and Mann. All but one of the isospin-mixed levels emit neutrons more copiously than protons, although we might expect about half of them to emit protons more copiously. We also present ${}^{10}B (α, p_{i}) {}^{13}C$ cross sections for groups which leave ${}^{13}C$ in the $½^{-}$ ground state; and in the $½^{+}$ 3.086, ${\frac{3}{2}}^{-} 3.684$ , and ${\frac{5}{2}}^{+} 3.854$ MeV excited states. We expanded the angular distributions in Legendre polynomials and fitted the coefficients at some of the resonances with compound nucleus scattering theory, obtaining spin-parity assignments: $1^{+}$ at $E_{x} ({}^{14}N) = 13.16, 2^{-} at 13.24, (2^{+}, 2^{-}, 3^{+}) at 13.67, and (1^{+}, 1^{-}) at 13.76$ MeV. As part of the calibration of the neutron spectrometer, we found the total ${}^{3}{He} (n, p) {}^{3}H$ cross section is 422±58 mb for 3.5 MeV neutrons. This value is about 20% lower than currently accepted values.

NUCLEAR REACTIONS ${}^{10}B (α, p_{i})$ $i = 0, 1, 2, 3$ ( $α, n_{0}$ ) $E = 2 - 10$ MeV; measured $σ (E, θ)$ ; deduced ${}^{14}N$ levels, $J$ , $π$ , isospin impurity. Enriched targets, resolution 50 keV, $θ = 10 - 160 °$ ; Legendre polynomial expansion of $σ (E, θ)$ ; absolute cross sections. Total $σ$ for ${}^{3}{He} (n, p)$ at $E_{n} = 3.5$ MeV.

Disintegration of ${}^{12}C$ , ${}^{19}F$ , ${}^{35}{Cl}$ , ${}^{63}{Cu}$ , and ${}^{65}{Cu}$ by real and virtual radiation

E. Wolynec, G. Moscati, J. R. Moreira, O. D. Gonçalves, and M. N. Martins

Phys. Rev. C 11, 1083 (1975) - Published 1 April, 1975

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Yield curves were measured for one neutron emission in ${}^{12}C$ , ${}^{19}F$ , ${}^{35}{Cl}$ , and ${}^{65}{Cu}$ , and for two neutron emission in ${}^{63}{Cu}$ , with target stacks which were bombarded by electrons. The results were analyzed to compare the yields from the direct effect of the electrons with those resulting from bremsstrahlung from the electrons. The analysis was carried out with the virtual photon method in the plane-wave Born approximation and the distorted-wave Born approximation (DWBA). Agreement with DWBA predictions is obtained assuming photoabsorption through $E 1$ transitions.

NUCLEAR REACTIONS ${}^{12}C$ , ${}^{19}F$ , ${}^{35}{Cl}$ , ${}^{65}{Cu}$ ; ( $γ, n$ ), ( $e, e^{'}, n$ ); ${}^{63}{Cu}$ , ( $γ, 2 n$ ), ( $e, e^{'}, 2 n$ ); $E = 16 - 39$ MeV; measured $\frac{σ_{γ} (E)}{σ_{e} (E)}$ ; DWBA virtual photon spectra analysis; deduced photoabsorption $λ$ .

Angular correlation and decay mode measurements in ${}^{41}{Ca}$ using the ${}^{42}{Ca} ({}^{3}{He}, α γ) {}^{41}{Ca}$ reaction

S. L. Tabor, R. W. Zurmühle, and D. P. Balamuth

Phys. Rev. C 11, 1089 (1975) - Published 1 April, 1975

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$γ$ -ray angular correlations have been measured for the 2.010, 2.960, 3.200, 3.526, 3.740, and 4.090 MeV states in ${}^{41}{Ca}$ using the ${}^{42}{Ca} ({}^{3}{He}, α γ)) {}^{41}{Ca}$ reaction. An $E 3$ strength of ( ${1.5}_{- 0.7}^{+ 0.9}$ ) Weisskopf units has been determined for the 2.010→0 MeV transition from the measured mixing ratio, $δ = - 0.095 \pm 0.022$ , and a previous lifetime measurement. The decay scheme and angular correlations imply a spin assignment of $J^{π} = {\frac{3}{2}}^{+}$ for the 3.526 MeV state and strongly suggest that $J^{π} = {\frac{3}{2}}^{+}$ for the 3.740 MeV state and $J^{π} = {\frac{5}{2}}^{+}$ for the 4.090 MeV state. Decay schemes have been measured for four $T = \frac{3}{2}$ states in ${}^{41}{Ca}$ at 5.814, 6.820, 7.146, and 8.54 MeV. Analog to antianalog state transitions have been observed from the 5.814, 6.820, and 7.146 MeV levels. Such a transition was not reported in a previous study of the decay of the 5.814 MeV state. The 8.54 MeV state decays primarily by neutron emission but has a 1 to 3% $γ$ -decay branch. In addition, the ${}^{41}K ({}^{3}{He}, t) {}^{41}{Ca}$ reaction was used to verify the $T = \frac{3}{2}$ assignment for the 5.814 MeV state and the ${}^{40}{Ca} (d, p γ) {}^{41}{Ca}$ reaction was used in the study of the 3.731-3.740 MeV doublet.

NUCLEAR REACTIONS ${}^{42}{Ca} ({}^{3}{He}, α)$ , $E = 18$ MeV; ${}^{41}K ({}^{3}{He}, t)$ , $E = 18$ MeV; ${}^{40}{Ca} (d, p)$ , $E = 11$ MeV; measured coinc. $γ$ spectrum, $I_{γ} (θ γ)$ . ${}^{41}{Ca}$ deduced $δ$ , $B (Λ)$ , $J$ , branching ratios.

Reactions ( ${}^{7}{Li}$ , ${}^{7}{Li}$ ), ( ${}^{7}{Li}$ , ${}^{6}{Li}$ ), and ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) on the deformed target ${}^{24}{Mg}$ at $E_{{}^{7}{Li}} = 34$ MeV

G. E. Moore, K. W. Kemper, and L. A. Charlton

Phys. Rev. C 11, 1099 (1975) - Published 1 April, 1975

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Angular distributions for the single nucleon transfer reactions ${}^{24}{Mg}$ ( ${}^{7}{Li}$ , ${}^{6}{Li}$ ) ${}^{25}{Mg}$ and ${}^{24}{Mg}$ ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) ${}^{25}{Al}$ have been measured to study the effects of target deformation on heavy-ion transfer reactions at $E_{{}^{7}{Li}} = 34$ MeV. Elastic and inelastic scattering angular distributions have also been measured for ${}^{7}{Li}$ + ${}^{24}{Mg}$ at the same energy. Optical model fits to the elastic scattering data were good in the diffraction region, but they overestimated the cross section at forward angles. Coupled channels calculations, which coupled the ground and first excited states of ${}^{24}{Mg}$ with ${}^{7}{Li}$ in its ground state, yielded deformation lengths that are in agreement with those obtained from light-ion scattering measurements. The single nucleon transfer data were compared to exact finite range distorted wave Born approximation calculations. While the extracted spectroscopic factors are in reasonable agreement with those obtained from light-ion works, the calculations are out of phase with the data. Parameter variations by as much as 20% did not resolve this problem. The cross sections for transitions to the $j$ -forbidden ${\frac{7}{2}}^{+}$ (1.61 MeV) states in ${}^{25}{Al}$ and ${}^{25}{Mg}$ were smaller relative to the allowed transitions than observed in corresponding light-ion single nucleon transfer reactions.

NUCLEAR REACTIONS ${}^{24}{Mg}$ ( ${}^{7}{Li}$ , ${}^{7}{Li}_{0, 1}$ ) ${}^{24}{Mg}_{0, 1}$ , $E = 34$ MeV; measured $σ (θ)$ ; deduced optical model parameters and deformation lengths for ${}^{24}{Mg}$ . ${}^{24}{Mg}$ ( ${}^{7}{Li}$ , ${}^{6}{Li}$ ), ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) $E = 34$ MeV; measured $σ (θ)$ ; deduced $S$ from finite range DWBA analysis.

Gamma ray linear polarization measurements for ${}^{29}{Al}$

J. R. Williams, R. O. Nelson, C. R. Gould, and D. R. Tilley

Phys. Rev. C 11, 1111 (1975) - Published 1 April, 1975

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Levels of ${}^{29}{Al}$ were populated with the ${}^{26}{Mg} (α, p) {}^{29}{Al}$ reaction at $E_{α} = 11.26$ MeV. The linear polarizations of $γ$ rays emitted in the decays of the 1.40-, 1.75-, 2.22-, and 2.87- MeV levels were measured. The polarization measurements are consistent with known spin-parity assignments for the 1.40- and 2.87-MeV levels, respectively. When combined with previously available information they indicate an assignment of ${\frac{3}{2}}^{+}$ for the 2.22-MeV level and ${\frac{7}{2}}^{+}$ ( ${\frac{3}{2}}^{+}$ ) for the 1.75-MeV level.

NUCLEAR REACTION ${}^{26}{Mg} (α, p)$ , $E = 11.26$ MeV; measured linear polarization, $p γ$ coincidence. ${}^{29}{Al}$ levels deduced $J$ , $π$ . Enriched target.

Neutron resonance spectroscopy: Aluminum

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

Phys. Rev. C 11, 1117 (1975) - Published 1 April, 1975

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The results are presented for high resolution neutron time of flight measurements on ${}^{27}{Al}$ from 4 to 420 keV. The $R$ -matrix multilevel shape analysis was used to obtain the resonance parameters for seven levels to 220 keV. We determined the strength functions as $10 {}^{4}S_{0} = ({3.25}_{- 1.7}^{+ 4.5})$ and $10 {}^{4}S_{1} = ({1.8}_{- 1.1}^{+ 3.5})$ . A channel radius of 4.2 fm was used in the calculation of $p$ -strength function. The ( $E_{0}, l, J, Γ_{n}$ ) choices were (5.895, 1, 1, 0.017), (34.59, 0, 2, 3.0), (85.69, 0, 3, 11.0), (119.6, 1, 2, 3.6), (142.0, 0, 3, 19.0), (158.2, 1, 3, 3.2), and (202.2, 0, 2, 14.5), where $E_{0}$ and $Γ_{n}$ are in keV.

NUCLEAR REACTIONS ${}^{27}{Al}$ ( $n, n$ ), ( $n, γ$ ), $E = 4 - 420$ keV; measured $σ_{t} (E)$ ; deduced $E_{0}$ , $l$ , $J$ , $Γ_{n}$ , $S_{0}$ , $S_{1}$ .

Recoil-distance lifetime measurements of ${}^{48}V$ levels

B. A. Brown, D. B. Fossan, J. M. McDonald, and K. A. Snover

Phys. Rev. C 11, 1122 (1975) - Published 1 April, 1975

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Lifetimes for a number of levels in ${}^{48}V$ have been measured using the recoil-distance technique. The experimental results for the mean lifetimes are 8.8±1.4 psec for the 428-keV $5^{+}$ level, 21.6±1.1 psec for the 613-keV $4^{+}$ level, 111±9 psec for the 627-keV $6^{+}$ level, 6.7±1.8 psec for the 1056-keV $3^{-}$ level, and 6.5±0.5 psec for the 1099-keV $4^{(-)}$ level. Lifetime limits were measured for other levels. The electromagnetic transition strengths for the positive and negative parity bands are discussed. For the positive parity levels, shell model calculations are carried out assuming wave functions of the form ${(π f_{\frac{7}{2}})}^{n} {(ν f_{\frac{7}{2}})}^{- n}$ . Many properties of ${}^{48}V$ and surrounding nuclei, particularly for the high-spin states, can be described using the ${}^{42}{Sc}$ effective interaction with effective operators $e_{p} + e_{n} = 2$ and $g_{p} - g_{n} = 1.29$ . For some aspects, however, the effective operator approach within this limited $1 f_{\frac{7}{2}}$ model space is not adequate.

NUCLEAR REACTIONS ${}^{45}{Sc} (α, n)$ $E = 9.5$ MeV; measured $n - γ$ coin, deduced levels in ${}^{48}V$ ; measured recoil distance, deduced $T_{\frac{1}{2}}$ , $B (L)$ , $π$ assignments. Natural target, Ge(Li) detectors.

Separable expansion of the $t$ matrix with analytic form factors

Sadhan K. Adhikari and I. H. Sloan

Phys. Rev. C 11, 1133 (1975) - Published 1 April, 1975

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A recently proposed separable expansion of the $t$ matrix (assuming the potential to be given) is rederived from the Schwinger variational principle. Also, analytic expressions are given for the integrals in the separable expansion if the potential is a superposition of Yukawa potentials, and for suitable choices of the expansion functions. Calculations with two commonly used $S$ -wave nucleon-nucleon potentials show that the expansion can converge significantly faster than the unitary pole expansion if the freedom in the choice of the expansion functions is exploited.

${}^{48}{Ti} ({}^{3}{He}, t) {}^{48}V$ reaction

J. C. Manthuruthil, C. P. Poirier, and L. Meyer-Schützmeister

Phys. Rev. C 11, 1141 (1975) - Published 1 April, 1975

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The ${}^{48}{Ti} ({}^{3}{He}, t) {}^{48}V$ reaction has been studied at an incident energy of $E_{{}^{3}{He}^{+ +}} = 25$ MeV with a split-pole magnetic spectrograph. A total of 35 levels in ${}^{48}V$ have been identified below an excitation energy of 3.05 MeV. Angular distributions have been measured for many levels and analyzed by means of the distorted-wave Born approximation. Definite $L$ -transfer value assignments have been made for many levels. Combining these results with previous work, spin assignments for some levels have been deduced. These results are compared with the predictions of a recent shell-model calculation which assumed a ${(π f_{\frac{7}{2}})}^{3} {(ν f_{\frac{7}{2}})}^{- 3}$ configuration. The isobaric analog of the ${}^{48}{Ti}$ ground state was located at an excitation energy of 3021 ± 10 keV, in good agreement with previous results.

NUCLEAR REACTIONS ${}^{48}{Ti} ({}^{3}{He}, t) {}^{48}V$ , $E = 25$ MeV; measured $σ (θ)$ , $θ = 7 ° - 65 °$ , determined $L$ transfers from DWBA; deduced $J$ , $π$ ; compared with shell model.

Effect of deuteron breakup on ( $d, p$ ) cross sections

George H. Rawitscher

Phys. Rev. C 11, 1152 (1975) - Published 1 April, 1975

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Deuteron-nucleus breakup wave functions, obtained in a previous study, are applied to calculate the contribution of breakup to zero range stripping matrix elements for the case of 21.6 MeV deuterons incident on ${}^{40}{Ca}$ . The results are compared with the method of Johnson and Soper. The two calculations agree quite well, but the Johnson-Soper method slightly overestimates the effect of breakup for the surface partial waves, and it suppresses too much the stripping amplitudes for the interior partial waves.

NUCLEAR REACTIONS Effect of deuteron breakup on $σ (d, p)$ . Comparison with Johnson-Soper theory for 21.6 MeV ${}^{40}{Ca} (d, p) {}^{41}{Ca}$ ( $2 p$ and $1 f$ ).

High-resolution study of ${}^{40}{Ca}$ via inelastic proton scattering at 35 MeV

J. A. Nolen, Jr. and R. J. Gleitsmann

Phys. Rev. C 11, 1159 (1975) - Published 1 April, 1975

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Spectra of inelastic proton scattering on ${}^{40}{Ca}$ have been obtained with 4.5 keV resolution at a bombarding energy of 35 MeV. Cross sections for the excitation of several previously unresolved particle-hole states have been measured. Nearly all known energy levels plus nine new levels have been observed up to an excitation energy of 9.3 MeV, slightly above the proton separation energy, and accurate excitation energies have been determined for these states.

NUCLEAR REACTIONS ${}^{40}{Ca} (p, p^{'})$ , $E = 35.2$ MeV; measured $σ (15 °, E_{p})$ , $σ (30 °, E_{p})$ ; deduced excitation energies; resolution 4.5 keV.

Relation between the Watson and Kerman-McManus-Thaler multiple scattering formalisms

M. A. Nagarajan, W. L. Wang, D. J. Ernst, and R. M. Thaler

Phys. Rev. C 11, 1167 (1975) - Published 1 April, 1975

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Electroexcitation of giant multipole resonances in ${}^{40}{Ca}$

Y. Torizuka, K. Itoh, Y. M. Shin, Y. Kawazoe, H. Matsuzaki, and G. Takeda

Phys. Rev. C 11, 1174 (1975) - Published 1 April, 1975

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A study of inelastic electron scattering from ${}^{40}{Ca}$ in the momentum transfer range $q = 0.43 - 1.40$ ${fm}^{- 1}$ has revealed strong excitations with quadrupole and octupole character which spread over the range of excitation energy $E_{x} = 10 - 25$ MeV. For comparison, a simple shell model calculation is made based on the quasielastic model.

NUCLEAR REACTIONS ${}^{40}{Ca} (e, e^{'})$ , measured $σ (E_{e}^{'}, θ_{e^{'}})$ , $E_{x} = 10 - 35$ MeV, $q = 0.43 \sim 1.4$ ${fm}^{- 1}$ . Enriched target.

Properties of excited states of ${}^{49}V$

B. Haas, J. Chevallier, J. Britz, and J. Styczen

Phys. Rev. C 11, 1179 (1975) - Published 1 April, 1975

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Excitation energies, spins and lifetimes have been measured in ${}^{49}V$ employing the reaction ${}^{46}{Ti} (α, p γ) {}^{49}V$ at a bombarding energy of 10.6 MeV. Reaction-produced protons were detected in an annular Si counter at an average angle of 171°. Coincident $γ$ -ray spectra were measured with a Ge(Li) detector at angles $120^{°} \geq θ \geq 0^{°}$ . Two Ge(Li) detectors were used in a $γ - γ$ coincidence experiment. The half-life of the 90.7 keV excited state, $T_{\frac{1}{2}} = 0.45 (3)$ ns, was measured by time-delayed $n - γ$ coincidences employing the reaction ${}^{46}{Ti} (p, n γ) {}^{49}V$ at a proton bombarding energy of 2.1 MeV. The results obtained for excitation energies, spins, parities, and lifetimes (ps) are: 748.3, ${\frac{3}{2}}^{+}$ , > 5, < 1000; 1021.6, ${\frac{11}{2}}^{-}$ , ${6.3}_{- 2.5}^{+ 3.9}$ ; 1140.9, ${\frac{5}{2}}^{+}$ , ${1.8}_{- 0.5}^{+ 0.9}$ ; 1155.4, ${\frac{9}{2}}^{-}$ , ${1.65}_{- 0.34}^{+ 0.48}$ ; 1514.4, ${\frac{5}{2}}^{-}$ , ${0.045}_{- 0.018}^{+ 0.021}$ ; 1603.1, ${\frac{7}{2}}^{+}$ , ${0.68}_{- 0.18}^{+ 0.31}$ ; 1643.1, $½^{(-)}$ , ${\frac{3}{2}}^{(-)}$ , ${\frac{5}{2}}^{(-)}$ , $½^{(+)}$ , ${0.050}_{- 0.014}^{+ 0.017}$ ; 1646.4, $½^{(+)}$ , ${\frac{3}{2}}^{(+)}$ , ${\frac{5}{2}}^{(+)}$ , > 7.5, < 1000; 1661.4, ${\frac{3}{2}}^{-}$ , < 0.04; 1994.9, ${\frac{3}{2}}^{+}$ , ${1.34}_{- 0.43}^{+ 0.80}$ ; 2178.5, ${\frac{9}{2}}^{+}$ , ${0.80}_{- 0.40}^{+ 0.70}$ ; 2182.7, ${\frac{7}{2}}^{-}$ , < 0.08; 2235.3, ${\frac{5}{2}}^{-}$ , < 0.05; 2263.3, ${\frac{15}{2}}^{-}$ , ${0.93}_{- 0.28}^{+ 0.55}$ ; 2265.2, ${\frac{3}{2}}^{-}$ , < 0.06; 2309.7, ${\frac{3}{2}}^{-}$ , < 0.07; 2353.3, ${\frac{9}{2}}^{-}$ , < 0.07; 2388.2, ${\frac{5}{2}}^{+}$ , ${0.09}_{- 0.02}^{+ 0.04}$ ; 2408.4, ${\frac{7}{2}}^{\pm}$ , ${\frac{9}{2}}^{-}$ , ${\frac{11}{2}}^{-}$ , < 0.03; 2670.8, ${\frac{9}{2}}^{-}$ , ${\frac{11}{2}}^{-}$ , ${\frac{13}{2}}^{-}$ , < 0.03; 2727.8, ${\frac{15}{2}}^{(-)}$ , ${0.35}_{- 0.11}^{+ 0.15}$ ; 2741.1, ${\frac{7}{2}}^{-}$ , ${\frac{9}{2}}^{\pm}$ , ${\frac{11}{2}}^{\pm}$ , ${0.70}_{- 0.50}^{+ 0.80}$ ; 2786.3, ${\frac{9}{2}}^{-}$ , ${\frac{11}{2}}^{-}$ , < 0.04; 2810.7, ${\frac{5}{2}}^{\pm}$ , ${\frac{7}{2}}^{\pm}$ , ${\frac{9}{2}}^{-}$ , < 0.06; 2860.8, ${\frac{13}{2}}^{-}$ , ${0.15}_{- 0.06}^{+ 0.08}$ ; 3017.3, ${\frac{3}{2}}^{\pm}$ , ${\frac{5}{2}}^{\pm}$ , ${\frac{7}{2}}^{\pm}$ , < 0.06; 3133.4, ( ${\frac{7}{2}}^{-}$ ), ${\frac{9}{2}}^{(+)}$ , ( ${\frac{11}{2}}^{-}$ ), < 0.06; 3133.7, ${\frac{9}{2}}^{(-)}$ , ${\frac{11}{2}}^{(-)}$ ,

${\frac{13}{2}}^{(-)}$ , ${0.32}_{- 0.06}^{+ 0.11}$ ; 3259.4, undetermined, > 3, < 1000; 3341.6, ${\frac{9}{2}}^{\pm}$ , ${\frac{11}{2}}^{\pm}$ , ${\frac{13}{2}}^{+}$ , > 5, < 1000. $γ$ -ray branching ratios and multipole mixing ratios were also obtained from the data, and reduced electromagnetic transition matrix elements have been extracted for a number of observed transitions. The positive parity states of ${}^{49}V$ were organized into two rotational bands with $K^{π} = {\frac{1}{2}}^{+}$ and $K^{π} = {\frac{3}{2}}^{+}$ . Calculations have been performed for negative parity states based on the strong-coupling model of Bohr and Mottelson with correctly treated phases in particle-hole excitations and the ${(Σ_{i} j_{i})}^{2}$ term in the Hamiltonian. The results are compared with experiment.

NUCLEAR REACTIONS ${}^{46}{Ti} (α, p γ)$ , $E_{α} = 10.6$ MeV and ${}^{49}{Ti} (p, n γ)$ , $E_{p} = 2.1$ MeV; measured $γ γ$ , $p γ$ , $n γ$ , $E_{γ}$ , $T_{\frac{1}{2}}$ , $δ$ for transitions in ${}^{49}V$ . Deduced $J$ , $π$ for levels.

Aspects of $π - d$ scattering in a relativistic three-body model

D. D. Brayshaw

Phys. Rev. C 11, 1196 (1975) - Published 1 April, 1975

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A relativistic three-body model of the $π - d$ system is employed to calculate elastic scattering in the (3, 3) resonance region. The results demonstrate that this effect is not related to a resonance pole in the $π - d$ amplitude, and may be simply understood in terms of well known rescattering singularities. Related questions concerning convergence of the multiple scattering series and pion absorption are discussed.

NUCLEAR REACTIONS ${}^{2, 2}H (π, π)$ ; calculated scattering amplitudes in three-body system.

Nucleus-nucleus reaction cross sections at high energies: Soft-spheres model

Paul J. Karol

Phys. Rev. C 11, 1203 (1975) - Published 1 April, 1975

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A simple analytical expression is derived for the total nuclear reaction cross section in heavy-ion heavy-ion collisions at high energies based on the semiclassical optical model. Tapered nuclear density distributions are used in conjunction with nucleon-nucleon collision cross sections.

NUCLEAR REACTIONS Nucleus-nucleus, high-energy; semiclassical calculation of total reaction cross sections, tapered density distributions.

General formalism for pion production in nuclei: Application to $pd \to t π$

Harold W. Fearing

Phys. Rev. C 11, 1210 (1975) - Published 1 April, 1975

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Motivated by the recent interest in ( $p, π$ ) reactions which leave the nucleus in a definite final state, we have obtained a general formalism for such reactions and applied it to the reaction $p d \to t π$ , for which there is recent medium energy data. The approach is essentially impulse approximation based on the assumption, originally used by Ruderman, that the reaction mechanism is the same as in $p p \to d π$ . It differs from previous such calculations in that we have included distortion effects and have derived and used an expression for the form factor which does not require the crude approximations for the wave functions used before. We apply this formula to $p d \to t π$ and obtain zero parameter fits which are a significant improvement over previous calculations and which reproduce the shape and normalization of the data quite well at 470 and 590 MeV and qualitatively at 340 MeV, except that as in other calculations the backward peak at 470 MeV is not reproduced. Distortion effects are important but purely absorptive and serve, as do most other theoretical uncertainties, simply to adjust the normalization.

NUCLEAR REACTIONS ( $p, π$ ) derived general formalism $σ (θ)$ at medium energies; distorted-wave impulse approx. Applied $d (p, π) t$ ; $E = 340, 470, 590$ MeV.

Determination of the critical angular momentum for heavy-ion fusion using the proximity potential

E. Seglie, D. Sperber, and A. Sherman

Phys. Rev. C 11, 1227 (1975) - Published 1 April, 1975

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The critical angular momentum for complete fusion is calculated using the classical dynamical theory. Ion-ion potentials as suggested by the Berkeley and Orsay groups are used. Reasonable agreement between the calculated and measured values of the critical angular momentum is obtained.

NUCLEAR REACTIONS Complete fusion cross section calculated for Ne on Al, Cu, Ag, and Bi; for Ar on Se, Sb, Th, and Ho; for Kr on Bi. $E = 4 - 10$ MeV/nucleon.

Neutron resonance spectroscopy: ${}^{175}{Lu}$

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

Phys. Rev. C 11, 1231 (1975) - Published 1 April, 1975

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Results are given of high resolution measurements of the neutron resonance parameters ( $E_{0}$ , $g Γ_{n}^{0}$ ) for 446 resonances to 3 keV in ${}^{175}{Lu}$ using the Columbia University Nevis synchrocyclotron. The measurements used the 202.05 m flight path for transmission measurements and the 39.57 m flight path for transmission, capture, and self-indication measurements. Values of $Γ_{γ}$ from (59 ± 20) to (100 ± 20) meV were obtained for 40 levels, with $〈 Γ_{γ} 〉 = 77$ meV. The $s$ wave strength function is $10 {}^{4}S_{0} = (1.83 \pm 0.12)$ and the deduced mean $s$ level spacing is (3.45 ± 0.15) eV. Using recent unpublished $J$ assignments for levels below 238 eV by Namenson, Stolovy, and Smith, we obtain (0.55 ± 0.20) for the ratio of the $J = 4$ to $J = 3$ $s$ strength functions. The results to 200 eV agree with values expected from the orthogonal ensemble theory for level spacing systematics.

NUCLEAR REACTIONS ${}^{175}{Lu} (n, n)$ , ( $n, γ$ ), $E = 1 eV - 3 keV$ ; measured $σ_{t}$ ( $E$ ); deduced $E_{0}$ , $g Γ_{n}^{0}$ , $Γ_{γ}$ , $S_{0}$ , $〈 D_{0} 〉$ , $\frac{S_{0} (J = 4)}{S_{0} (J = 3)}$ ; various statistical tests.

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Erratum: Consequences of isospin and other conserved quantum numbers for compound-nucleus reactions

${}^{10}B (α, n_{0}) {}^{13}N$ and ${}^{10}B (α, p_{i}) {}^{13}C$ for $2 < E_{α} < 8$ MeV

Disintegration of ${}^{12}C$ , ${}^{19}F$ , ${}^{35}{Cl}$ , ${}^{63}{Cu}$ , and ${}^{65}{Cu}$ by real and virtual radiation

Angular correlation and decay mode measurements in ${}^{41}{Ca}$ using the ${}^{42}{Ca} ({}^{3}{He}, α γ) {}^{41}{Ca}$ reaction

Reactions ( ${}^{7}{Li}$ , ${}^{7}{Li}$ ), ( ${}^{7}{Li}$ , ${}^{6}{Li}$ ), and ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) on the deformed target ${}^{24}{Mg}$ at $E_{{}^{7}{Li}} = 34$ MeV

Gamma ray linear polarization measurements for ${}^{29}{Al}$

Neutron resonance spectroscopy: Aluminum

Recoil-distance lifetime measurements of ${}^{48}V$ levels

Separable expansion of the $t$ matrix with analytic form factors

${}^{48}{Ti} ({}^{3}{He}, t) {}^{48}V$ reaction

Effect of deuteron breakup on ( $d, p$ ) cross sections

High-resolution study of ${}^{40}{Ca}$ via inelastic proton scattering at 35 MeV

Relation between the Watson and Kerman-McManus-Thaler multiple scattering formalisms

Electroexcitation of giant multipole resonances in ${}^{40}{Ca}$

Properties of excited states of ${}^{49}V$

Aspects of $π - d$ scattering in a relativistic three-body model

Nucleus-nucleus reaction cross sections at high energies: Soft-spheres model

General formalism for pion production in nuclei: Application to $pd \to t π$

Determination of the critical angular momentum for heavy-ion fusion using the proximity potential

Neutron resonance spectroscopy: ${}^{175}{Lu}$

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