Recent Articles

Extra nodes and the phase shift of the scattering wave function for a nonlocal potential

B. Bagchi, T. O. Krause, and B. Mulligan

Phys. Rev. C 15, 1623 (1977) - Published 1 May, 1977

Show Abstract

This paper examines the presence of extra nodes in the scattering wave function for a nonlocal potential. Extra nodes are known to result from the nonlocality of an effective potential which incorporates the Pauli principle. It is shown that an extra node is directly linked to the existence of a continuum bound state or a spurious state in the scattering spectrum. Thus the presence of extra nodes occurs in conjunction with zeros of the Fredholm determinants $D^{\pm} (k)$ and $D (k)$ associated with the integral equations for the physical and regular scattering solutions, respectively. The behavior of the nodes due to spurious states and continuum bound states is differentiated. Two possible definitions of the phase shift for a nonlocal potential are discussed in connection with this behavior. Both are consistent with the local limit. The definition of the phase shift as the negative of the phase of the Jost function $L^{+} (k)$ is suggested as preferable. This definition is shown to be in accord with the nodal behavior of the wave function and its interpretation in terms of an absolute value of the phase shift. Examples of potentials with a spurious state and of potentials with a continuum bound state are given. The nodal behavior of the wave function and the associated phase shift behavior are examined for each.

NUCLEAR REACTIONS Scattering by a nonlocal potential, extra nodes, Fredholm determinants and their zeros, continuum bound states, spurious states, phase shifts.

Measurement of the 2200 m/sec neutron-proton capture cross section

D. Cokinos and E. Melkonian

Phys. Rev. C 15, 1636 (1977) - Published 1 May, 1977

Show Abstract

The neutron-proton capture cross section at the neutron laboratory velocity of 2200 m/sec has been determined from the time decay of the thermalized neutron population following short bursts of fast neutrons in water samples of widely varying sizes. Use of an intense pulsed neutron beam enables elimination of many of the problems encountered in earlier experiments. The present result for this cross section is 332.6±0.7 mb, which is the most precise of any result obtained by this method and is comparable in accuracy and consistent with the most accurate values determined by any method.

NUCLEAR REACTIONS $p (n, γ) d$ , $E = 0.0253$ eV; measured lifetimes of thermal neutrons in water samples of various sizes; deduced $σ_{a}$ .

Giant quadrupole resonance in ${}^{24}{Mg}$ , ${}^{27}{Al}$ , and ${}^{28}{Si}$

D. H. Youngblood, C. M. Rozsa, J. M. Moss, D. R. Brown, and J. D. Bronson

Phys. Rev. C 15, 1644 (1977) - Published 1 May, 1977

Show Abstract

The giant-resonance region of ${}^{24}{Mg}$ , ${}^{27}{Al}$ , and ${}^{28}{Si}$ was studied by inelastic scattering of 126-MeV α particles. In contrast to results at 96 MeV, considerable clustering of $E 2$ strength was observed for ${}^{27}{Al}$ at $E_{x} \sim 20.1$ MeV with $Γ \sim 7.6$ MeV exhausting about 35% of the $E 2$ energy weighted sum rule. $E 2$ strength was also located in ${}^{24}{Mg}$ in two clusters of states at ${\bar{E}}_{x} \sim 18.2, 24.4$ MeV; however, contributions from other multipoles cannot be neglected. In ${}^{28}{Si}$ a multipeaked group was observed at $E_{x} \sim 19.4$ MeV with $Γ \sim 4$ MeV but no $L$ assignment was made. The energy dependence of the cross section for the giant quadrupole resonance was found to be consistent with distorted-wave Born approximation predictions.

NUCLEAR REACTIONS ${}^{24}{Mg}$ , ${}^{27}{Al}$ , ${}^{28}{Si} (α, α^{'})$ , $E = 126$ MeV; measured $σ (θ)$ giant resonances, deduced $l$ , sum rule fraction.

( $p, d {}^{3}{He}$ ) reaction as a quasifree reaction process

A. A. Cowley, P. G. Roos, N. S. Chant, R. Woody, III., H. D. Holmgren, and D. A. Goldberg

Phys. Rev. C 15, 1650 (1977) - Published 1 May, 1977

Show Abstract

The ( $p, d {}^{3}{He}$ ) reaction of ${}^{6}{Li}$ , ${}^{7}{Li}$ , ${}^{9}{Be}$ , and ${}^{12}C$ has been investigated in conjunction with studies of the ( $p, p α$ ) reaction on the same targets. Coincident data for all four targets were obtained at a bombarding energy of 100 MeV for numerous angle pairs in order to test the reaction mechanism. Comparisons of the ( $p, d {}^{3}{He}$ ) data to both ( $p, p α$ ) data and distorted-wave impulse approximation calculations indicate a dominance of the direct quasifree reaction process ( $p + α \to d + {}^{3}{He}$ ). The absolute $α$ -particle spectroscopic factors extracted using distorted-wave impulse approximation analysis are in agreement with the values obtained in the ( $p, p α$ ) reaction.

NUCLEAR REACTIONS ${}^{6}{Li}$ , ${}^{7}{Li}$ , ${}^{9}{Be}$ , ${}^{12}C (p, d {}^{3}{He})$ , $E_{0} = 100$ MeV; measured $\frac{d^{3} σ}{d Ω_{d} d Ω_{{}^{3}{He}}}$ $d E_{d} (θ_{d}, θ_{{}^{3}{He}}, E_{d})$ ; coplanar geometry; DWIA analysis; deduced $α$ -particle spectroscopic factors.

$0^{+}$ and $1^{+}$ states in ${}^{24}{Na}$

K. D. Singer, S. C. Headley, L. R. Medsker, and H. T. Fortune

Phys. Rev. C 15, 1662 (1977) - Published 1 May, 1977

Show Abstract

The observation of $L = 0$ angular distributions in ${}^{22}{Ne} ({}^{3}{He}, p) {}^{24}{Na}$ , when combined with previous results, yields unique $J^{π}$ assignments of $1^{+}$ to states at 2980, 3415, and 3594 keV. Three additional states are found to have $J^{π} = 0^{+} or 1^{+}$ .

NUCLEAR REACTIONS ${}^{22}{Ne} ({}^{3}{He}, p)$ , $E = 18.0$ MeV; measured $σ (θ, E_{p})$ . ${}^{24}{Na}$ deduced levels, $L$ , $π$ , $J$ . DWBA analysis.

Gamma-ray angular distribution measurements from the ${}^{162, 164}{Dy} (n, n^{'} γ)$ reactions

H. R. Hooper, J. M. Davidson, P. W. Green, D. M. Sheppard, and G. C. Neilson

Phys. Rev. C 15, 1665 (1977) - Published 1 May, 1977

Show Abstract

A study has been made of energy levels below 1.4 MeV excited in the ${}^{162, 164}{Dy} (n, n^{'} γ)$ reactions. $γ$ -ray angular distributions were measured, and spins and $γ$ -ray multipole mixing ratios deduced.

NUCLEAR REACTIONS ${}^{162, 164}{Dy} (n, n^{'} γ)$ , $E = 1.5 - 2.4$ MeV; measured $σ (E_{γ}, θ_{γ})$ ; ${}^{162, 164}{Dy}$ deduced levels, $J$ , $π$ , $δ$ . Enriched targets. Ge(Li) detectors.

Reduced transition probabilities of vibrational states in ${}^{154 - 160}{Gd}$ and ${}^{176 - 180}{Hf}$

R. M. Ronningen, J. H. Hamilton, A. V. Ramayya, L. Varnell, G. Garcia-Bermudez, J. Lange, W. Lourens, L. L. Riedinger, R. L. Robinson, P. H. Stelson, and J. L. C. Ford, Jr.

Phys. Rev. C 15, 1671 (1977) - Published 1 May, 1977

Show Abstract

The vibrational states of ${}^{154, 156, 158, 160}{Gd}$ and ${}^{176, 178, 180}{Hf}$ have been studied via Coulomb excitation. Thin high-purity targets were prepared in an isotope separator. Coulomb excitation of these nuclei was studied by the scattering of 11-17 MeV $α$ particles. The particles were detected in an Enge split-pole spectrograph. The reduced transition probabilities $B (E λ; 0_{g . s .}^{+} \to I^{π} K)$ , were obtained for $I^{π} K = 2^{+} 2$ states in each nucleus, and for $I^{π} K = 2^{+} 0$ and $I^{π} = 3^{-}$ states in several nuclei. The $K^{π} = 2^{+}$ levels are reasonably constant in energy and $B (E 2)$ strength while the $K^{π} = 0^{+}$ states change rapidly in energy and excitation strength with neutron number. In both the softly deformed Gd nuclei and the more strongly deformed Hf nuclei, the lightest nucleus has the lowest energy and largest $B (E 2)$ for an $I^{π} K = 2^{+} 0$ state, despite the difference in the sizes of the deformations at these lightest masses.

NUCLEAR REACTIONS ${}^{154 - 160}{Gd} (α, α^{'})$ , ${}^{176 - 180}{Hf} (α, α^{'})$ , $E = 11 - 17$ MeV; measured $σ$ , deduced $B (E λ)$ and $M (E λ)$ . Enriched targets.

Electromagnetic transition probabilities in ${}^{65}{Zn}$

A. Charvet, J. Sau, R. Duffait, and R. Chery

Phys. Rev. C 15, 1679 (1977) - Published 1 May, 1977

Show Abstract

The levels of ${}^{65}{Zn}$ have been investigated via the ${}^{65}{Cu} (p, n γ) {}^{65}{Zn}$ reaction up to 1.5 MeV and the ${}^{62}{Ni} (α, n γ) {}^{65}{Zn}$ reaction up to 1.1 MeV excitation. The previously reported levels have been confirmed and several new transitions are proposed. The lifetimes of 10 levels in ${}^{65}{Zn}$ have been measured by the Doppler shift attenuation method. The experimental reduced transition probabilities are compared with theoretical calculations performed in the frame of the weak coupling model.

NUCLEAR REACTIONS ${}^{65}{Cu} (p, n γ)$ , $E_{p} = 3.4 - 4.0$ MeV; ${}^{62}{Ni} (α, n γ)$ , $E_{α} = 8.2$ MeV, enriched targets, measured $E_{γ}$ , $I_{γ}$ , $Δ E_{γ} (τ)$ , confirmed ${}^{65}{Zn}$ levels, deduced $τ$ .

Masses of ${}^{61}{Fe}$ and ${}^{62}{Fe}$

J. D. Cossairt, R. E. Tribble, and R. A. Kenefick

Phys. Rev. C 15, 1685 (1977) - Published 1 May, 1977

Show Abstract

The mass excesses of ${}^{61}{Fe}$ and ${}^{62}{Fe}$ have been measured using the ${}^{64}{Ni} (α, {}^{7}{Be}) {}^{61}{Fe}$ and ${}^{64}{Ni}$ ( ${}^{11}B$ , ${}^{13}N$ ) ${}^{62}{Fe}$ reactions. The mass excesses obtained are $M ({}^{61}{Fe}) = - 58.92 \pm 0.02$ MeV and $M ({}^{62}{Fe}) = - 58.85 \pm 0.07$ MeV. The results are consistent with recent predictions from two different mass relations.

NUCLEAR REACTIONS ${}^{64}{Ni} (α, {}^{7}{Be})$ and ${}^{64}{Ni}$ ( ${}^{11}B$ , ${}^{13}N$ ). Measured ${}^{61}{Fe}$ and ${}^{62}{Fe}$ masses. Compared with predictions.

Gamma spectroscopy of ${}^{52}{Fe}$ , ${}^{52}{Mn}$ , and ${}^{52}{Cr}$ from $α$ + ${}^{50}{Cr}$ reactions

D. Evers, A. Harasim, R. L. McGrath, and W. Assmann

Phys. Rev. C 15, 1690 (1977) - Published 1 May, 1977

Show Abstract

The ${}^{50}{Cr} (α, 2 n γ) {}^{52}{Fe}$ reaction has been used at incident energies of 23.5 and 27.2 MeV to search for states in ${}^{52}{Fe}$ . Triple coincidence data were obtained. The first $2^{+}$ and $4^{+}$ states were located at 848.3 ± 0.9 and 2383.3 ± 1.3 keV, respectively. No $γ$ rays from higher spin ${}^{52}{Fe}$ states were detected. A number of $γ$ rays associated with states populated in the ( $α, pp γ$ ) and ( $α, np γ$ ) reactions were observed. Two previously unreported states were located at 6452.1 ± 0.7 and 4163.7 ± 0.5 keV in ${}^{52}{Cr}$ and ${}^{52}{Mn}$ , respectively. The relative yields of many $γ$ rays were consistent with compound nucleus evaporation calculations.

NUCLEAR REACTIONS ${}^{50}{Cr} (α, X γ)$ , $E = 23.5 and 27.2$ MeV measured $σ_{rel} (90 °, E_{γ})$ in ( $γ, γ$ ) and ( $n, n, γ$ ) coincidences, ${}^{52}{Cr}$ , ${}^{52}{Mn}$ , and ${}^{52}{Fe}$ deduced levels, $J$ , $π$ . Enriched target.

Compound nucleus ( $α, p$ ) and ( $p, p^{'}$ ) reactions on odd- $A$ nuclei in the Ni region

K. C. Chan, L. Shabason, B. L. Cohen, J. Alzona, and T. Congedo

Phys. Rev. C 15, 1698 (1977) - Published 1 May, 1977

Show Abstract

Experimental compound nucleus cross sections are obtained for ( $p, p^{'}$ ) and ( $α, p$ ) reactions induced by 12 MeV protons and 15 and 18 MeV $α$ particles on ${}^{55}{Mn}$ , ${}^{57}{Fe}$ , ${}^{59}{Co}$ , ${}^{61}{Ni}$ , and ${}^{63}{Cu}$ . The noncompound nucleus cross sections, estimated from the spectra from ${}^{64}{Ni}$ , are found to account for at least 20% of the total proton cross sections and also soften the spectra in the ( $p, p^{'}$ ) cases. When these are subtracted off, good agreement in spectral intensities is found between experimental compound nucleus cross sections and predictions using Hauser-Feshbach calculations with Gilbert-Cameron level density parameters. No adjustable parameters were used. The slopes of the proton energy spectra from both ( $p, p^{'}$ ) and ( $α, p$ ) reactions are consistently flatter (i.e., decrease less rapidly with increasing proton energy) for odd- $A$ than for even-even targets.

NUCLEAR REACTIONS: ${}^{55}{Mn}$ , ${}^{57}{Fe}$ , ${}^{59}{Co}$ , ${}^{61}{Ni}$ , ${}^{63}{Cu}$ , ${}^{65}{Cu} (α, p)$ , $E_{α} = 15, 18$ MeV; ${}^{55}{Mn}$ , ${}^{57}{Fe}$ , ${}^{59}{Co}$ , ${}^{61}{Ni}$ , ${}^{63}{Cu} (p, p^{'})$ , $E_{p} = 12$ MeV. Measured compound nucleus cross sections.

Spin and $g$ factor of the 40-keV level in ${}^{45}{Ti}$

J. Styczen, A. Chevallier, J. Chevallier, B. Haas, N. Schulz, and M. Toulemonde

Phys. Rev. C 15, 1704 (1977) - Published 1 May, 1977

Show Abstract

The $g$ factor of the second excited state at 40 keV in ${}^{45}{Ti}$ has been measured to be -0.03 ± 0.01 using the ${}^{42}{Ca} (α, n) {}^{45}{Ti}$ reaction and the time differential spin-precession method. The spin assignment $J = \frac{5}{2}$ was made for the level using a statistical compound nucleus calculation. The experimental $g$ factor is in disagreement with several theoretical predictions.

NUCLEAR REACTIONS ${}^{42}{Ca} (α, n)$ , $E = 6.5$ MeV; measured $γ (θ)$ and $γ (θ, H, t)$ . ${}^{45}{Ti}$ 40 keV level deduced $J^{π}$ , $T_{\frac{1}{2}}$ , and $g$ . Enriched target, Ge(Li) counters.

Level structure of ${}^{57}{Mn}$ from a ${}^{55}{Mn} (t, p) {}^{57}{Mn}$ reaction study and a mixed-configuration shell model calculation

J. F. Mateja, C. P. Browne, C. E. Moss, and J. B. McGrory

Phys. Rev. C 15, 1708 (1977) - Published 1 May, 1977

Show Abstract

Twenty-seven levels below 2.7 MeV excitation in ${}^{57}{Mn}$ have been identified using the ${}^{55}{Mn} (t, p) {}^{57}{Mn}$ reaction. Of these levels 18 were not reported in an earlier ${}^{54}{Cr} (α, p) {}^{57}{Mn}$ and ${}^{54}{Cr} (α, p γ) {}^{57}{Mn}$ work. From a distorted-wave Born approximation analysis of the angular distributions for states up to 2.1 MeV, the $J = \frac{5}{2}$ ground state spin was confirmed and $J = \frac{5}{2} and (\frac{11}{2})$ spin assignments were made to levels at 1837 and 1916 keV, respectively. Further, the $L$ values extracted from the ${}^{55}{Mn} (t, p) {}^{57}{Mn}$ angular distributions were consistent with all of the tentative spin assignments given in the ${}^{54}{Cr} (α, p γ) {}^{57}{Mn}$ study. The ground state $Q$ value is 7438.2 ± 3.6 keV. A shell model calculation for ${}^{57}{Mn}$ was also attempted. A ${}^{48}{Ca}$ core was assumed with the valence protons restricted to the $f_{\frac{7}{2}}$ subshell and the valence neutrons allowed to occupy the $2 p_{\frac{3}{2}}$ , $1 f_{\frac{5}{2}}$ , and $2 p_{\frac{1}{2}}$ subshells. The agreement between the experimental and predicted level schemes is extremely good to 2 MeV. Above 2 MeV where core and valence particle excitations are expected, the model begins to break down since these configurations were not included in the model's configuration space. The shell model wave functions were also used to calculate spectroscopic amplitudes for two nucleon transfer reactions. The quantitative agreement between the predicted strengths and the strengths extracted from the experiment for the ${}^{55}{Mn} (t, p) {}^{57}{Mn}$ reaction is satisfactory.

NUCLEAR REACTIONS ${}^{55}{Mn} (t, p)$ , $E (t) = 17.0$ MeV, Q3D spectrograph; measured excitation energies, $σ (θ, E_{p})$ , DWBA analysis; ${}^{57}{Mn}$ deduced $L$ , $J$ , $π$ , enhancement factors; shell model calculation.

Single-neutron transfer to ${}^{29}{Si}$ , ${}^{41, 49}{Ca}$ , and ${}^{55}{Fe}$ states induced by the ( ${}^{18}O$ , ${}^{17}O$ (g.s.)) and ( ${}^{18}O$ , ${}^{17}O$ (0.87 MeV)) reactions

J. F. Petersen, D. Dehnhard, and B. F. Bayman

Phys. Rev. C 15, 1719 (1977) - Published 1 May, 1977

Show Abstract

Differential cross sections for the ( ${}^{18}O$ , ${}^{17}O$ ) reaction on targets of ${}^{28}{Si}$ , ${}^{40, 48}{Ca}$ , and ${}^{54}{Fe}$ have been measured at $E ({}^{18}O) = 50$ MeV. The ${}^{17}O$ nuclei were detected in both the ground state ( $\frac{5}{2^{+}}$ ) and the first excited state (0.87 MeV, $\frac{1}{2^{+}}$ ). The data were analyzed using full-recoil finite-range distorted-wave Born-approximation calculations. Spectroscopic factors were, with one exception, in good agreement with the products of spectroscopic factors obtained from light ion reactions. In particular, the ratio of spectroscopic factors for neutron pickup from ${}^{18}O$ , $\frac{S ({}^{18}O \to {}^{17}O (0.87 MeV)}{S ({}^{18}O \to {}^{17}O (g . s .))}$ , was found to be independent of the target. Thus these data are consistent with a one-step direct reaction interpretation of the transfer. However, some problems remain in connection with understanding the location of the grazing angle peaks in the angular distributions.

NUCLEAR REACTIONS ${}^{28}{Si}$ , ${}^{40, 48}{Ca}$ , ${}^{54}{Fe}$ ( ${}^{18}O$ , ${}^{17}O$ ), $E = 50$ MeV; measured $σ (E, ⊖)$ ${}^{17}O$ , ${}^{29}{Si}$ , ${}^{41, 49}{Ca}$ , ${}^{55}{Fe}$ levels, deduced $S$ . Enriched targets, DWBA analysis, resolution 100 keV; $⊖ = 20 ° - 80 °$ .

Spectroscopic information from the ${}^{9}{Be}$ ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) ${}^{10}B$ and ${}^{9}{Be}$ ( ${}^{7}{Li}$ , ${}^{6}{Li}$ ) ${}^{10}{Be}$ reactions

K. W. Kemper, G. E. Moore, R. J. Puigh, and R. L. White

Phys. Rev. C 15, 1726 (1977) - Published 1 May, 1977

Show Abstract

Elastic scattering of ${}^{7}{Li}$ + ${}^{9}{Be}$ and ${}^{6}{Li}$ + ${}^{10}B$ has been measured at $E ({}^{7}{Li}) = 34$ MeV and $E ({}^{6}{Li}) = 30$ MeV and the data have been described with the standard optical model. Both ${}^{9}{Be}$ ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) and ${}^{9}{Be}$ ( ${}^{7}{Li}$ , ${}^{6}{Li}$ ) reaction data were measured. Extreme forward angle ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) data were taken so that the $j$ transfer ( $\frac{3}{2}$ or ½) to the first two $1^{+}$ states in ${}^{10}B$ could be determined. Both states were found to be populated predominantly by $p_{\frac{1}{2}}$ transfers. The absolute spectroscopic factors obtained are in good agreement with 35 MeV ( ${}^{3}{He}$ , $d$ ) data, but not with 17 MeV data. Comparison between the spectroscopic factors obtained from the ( $d, n$ ), ( ${}^{3}{He}$ , $d$ ), and ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) reactions shows a clear need for the energy dependence of these reactions to be understood before reliable absolute spectroscopic factors for ${}^{10}B$ can be obtained. The ( ${}^{7}{Li}$ , ${}^{6}{Li}$ ) results were in good agreement with the calculations of Cohen and Kurath, in contrast to the ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) results.

NUCLEAR REACTIONS ${}^{7}{Li}$ + ${}^{9}{Be}$ , 34 MeV; ${}^{6}{Li}$ + ${}^{10}B$ , 30 MeV; measured $σ (θ)$ ; deduced optical model parameters. ${}^{9}{Be}$ ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) ${}^{10}B$ , 34 MeV; measured $σ (θ)$ ; deduced $j$ transfer; ${}^{9}{Be}$ ( ${}^{7}{Li}$ , ${}^{6}{Li}$ ) ${}^{10}{Be}$ , 34 MeV; measured $σ (θ)$ . Deduced $S ({}^{10}B)$ and $S ({}^{10}{Be})$ from finite-range DWBA analysis.

Deformed $\frac{9}{2^{+}}$ proton-hole states in odd- $A$ I nuclei

D. B. Fossan, M. Gai, A. K. Gaigalas, D. M. Gordon, R. E. Shroy, K. Heyde, M. Waroquier, H. Vincx, and P. Van Isacker

Phys. Rev. C 15, 1732 (1977) - Published 1 May, 1977

Show Abstract

$Δ J = 1$ bands built on low-lying $\frac{9}{2^{+}}$ states (307 keV in ${}^{119}I$ ) have been observed in odd- $A$ ${}^{117.127}I$ ( $Z = 53$ ) nuclei via ( ${}^{6}{Li}$ , $3 n γ$ ) reactions. Calculations of the total potential energy of these nuclear states in terms of a $[404] \frac{9}{9^{+}}$ Nilsson proton hole revealed minima at significant prolate deformations ( $ε = 0.22$ for ${}^{119}I$ ). The resulting excitation energies and band spacing calculations are in good agreement with experiment. The properties of these deformed $\frac{9}{2^{+}}$ states, which involve a $1 g_{\frac{9}{2}}$ proton excited through the $Z = 50$ major shell, are compared with those of the deformed $\frac{9}{2^{+}}$ states previously observed in odd-Sb ( $Z = 51$ ) nuclei.

NUCLEAR REACTIONS ${}^{114 - 124}{Sn} ({}^{6}{Li}, 3 n)$ , $E_{Li} = 25 - 35$ MeV, measured $γ - γ$ coincidences, $γ (E, θ, t)$ ; deduced level scheme in odd- $A$ ${}^{117 - 127}I$ , $γ$ multipolarities, $J^{π}$ . Enriched targets, Ge(Li) detectors.

NUCLEAR STRUCTURE Odd- $A$ ${}^{117 - 127}I$ , calculated ${\frac{9}{2}}^{+}$ proton-hole state energies, $Δ J = 1$ rotational bands.

Mass of ${}^{19}N$

C. Détraz, F. Naulin, M. Langevin, P. Roussel, M. Bernas, F. Pougheon, and J. Vernotte

Phys. Rev. C 15, 1738 (1977) - Published 1 May, 1977

Show Abstract

${}^{19}N$ nuclei from the ${}^{18}O$ ( ${}^{18}O$ , ${}^{19}N$ ) ${}^{17}F$ reaction at 91 MeV have been observed. The mass excess of ${}^{19}N$ is measured as 15.81 ± 0.09 MeV, a value located in between the conflicting predictions of the Garvey-Kelson formula and the modified shell-model mass equation.

NUCLEAR REACTIONS ${}^{18}O$ ( ${}^{18}O$ , ${}^{19}N$ ) ${}^{17}F$ ; $θ = 10 °$ ; $E ({}^{18}O) = 91$ MeV; enriched target; measured $Q$ , deduced mass excess of ${}^{19}N$ .

Gamma-ray spectroscopic studies on high-spin states in ${}^{71}{As}$ and ${}^{73}{As}$ using heavy-ion reactions

B. Heits, H. -G. Friederichs, A. Rademacher, K. O. Zell, P. von Brentano, and C. Protop

Phys. Rev. C 15, 1742 (1977) - Published 1 May, 1977

Show Abstract

The heavy-ion reactions ( $α, 2 n$ ) and ( ${}^{18}O$ , $p 2 n$ ) have been used to study by $γ$ -ray spectroscopy the nuclei ${}^{71}{As}$ and ${}^{73}{As}$ with emphasis on high-spin states. Spin and parity assignments were made on the basis of coincidence measurements, angular distributions, and excitation functions. Level schemes for ${}^{71}{As}$ and ${}^{73}{As}$ have been constructed which contain a stretched spin band on a $g_{\frac{9}{2}}$ state.

NUCLEAR REACTIONS ${}^{69, 71}{Ga} (α, 2 n)$ , $E_{α} = 17 - 24$ MeV; ${}^{56, 58}{Fe} ({}^{18}O, p 2 n)$ , $E_{0} = 40 - 52.5$ MeV; measured $E_{γ}$ , $I_{γ}$ , $σ (E, E_{γ})$ , $I_{γ} (θ)$ , $γ - γ$ coincidence; ${}^{71}{As}$ , ${}^{73}{As}$ deduced levels, $J$ , $π$ ; enriched targets; Ge(Li).

Spin-flip transitions caused by ${}^{6}{Li}$ inelastic scattering and a microscopic $α$ -spectator model

K. -I. Kubo, K. Nagatani, and K. G. Nair

Phys. Rev. C 15, 1758 (1977) - Published 1 May, 1977

Show Abstract

Inelastic deuteron scattering on ${}^{12}C$ has been studied using a microscopic description for both target and projectile nuclei. From the fits of the calculated results to the experimental data, the effective two-body interaction strength has been extracted. The Wigner part of the interaction was obtained from the analysis of the 4.43-MeV ( $2^{+}$ ) state excitation and the result is compared with those found previously. The spin-spin part of the interaction was examined by the analysis of the 12.71-MeV ( $1^{+}$ ) state. In addition, the consistency of our results was also checked by analyzing inelastic ${}^{3}{He}$ scattering. The real purpose of the present work was, however, to investigate such a treatment when applied to heavier projectile scattering. For this purpose, the inelastic ${}^{6}{Li}$ scattering leading to the 12.71-MeV ( $1^{+}$ ) state was studied. Assuming the transition to be a spinflip process, an $α$ -spectator model based on the cluster description of ${}^{6}{Li}$ was used. Therefore, this analysis may be considered an extension of the ordinary microscopic treatment with the nucleon-nucleon interaction to the cluster description. The results of the effective interaction strengths are presented for various radial shapes of the nucleon-nucleon interaction. The effects of more complicated possible processes are also discussed.

NUCLEAR REACTIONS Microscopic calculations of differential cross sections: ${}^{12}C (d, d^{'})$ , $E = 28 52$ MeV; ${}^{12}C$ ( ${}^{3}{He}$ , ${}^{3}{He}$ ′), $E = 49.8$ MeV; ${}^{12}C$ ( ${}^{6}{Li}$ , ${}^{6}{Li}$ ′), $E = 36.4$ MeV; $α$ -spectator model for ( ${}^{6}{Li}$ , ${}^{6}{Li}$ ′); deduced effective two-body interaction strengths.

Apparent puzzles in the analyses of the ${}^{30}{Si}$ ( ${}^{16}O$ , ${}^{15}N$ ) ${}^{31}P$ reaction data

K. G. Nair and K. -I. Kubo

Phys. Rev. C 15, 1774 (1977) - Published 1 May, 1977

Show Abstract

The angular distributions for the reaction ${}^{30}{Si}$ ( ${}^{16}O$ , ${}^{15}N$ ) ${}^{31}P$ (g.s., $\frac{1}{2^{+}}$ ) at 60 MeV and 73.5 MeV ( $l = 1$ transfer) are seen to exhibit anomalous behavior in contradiction to previous distorted-wave Born approximation analyses of the same data. It is pointed out that previous observations of "nonanomaly" are due to the use of optical parameters which are arbitrarily different from those used to fit elastic scattering data. This procedure appears to be related to the simulation of coupled-channel effects. Angular distributions to the ${}^{31}P$ (1.27, $\frac{3}{2^{+}}$ ) and ${}^{31}P$ (2.23, $\frac{5}{2^{+}}$ ) states also show anomalies. Actually, a similar procedure based on coupled-channel arguments (the modified-radius Born approximation) explains these anomalies to a large extent and results in extracted spectroscopic factors which are more realistic.

NUCLEAR REACTIONS ${}^{30}{Si}$ ( ${}^{16}O$ , ${}^{15}N$ ), $E = 60$ MeV, 73.5 MeV; ${}^{31}P$ levels; DWBA analyses; anomalies; core excitation effects.

Select page:

Physical Review C

Recent Articles

Filter

Recent Issues

Extra nodes and the phase shift of the scattering wave function for a nonlocal potential

Measurement of the 2200 m/sec neutron-proton capture cross section

Giant quadrupole resonance in ${}^{24}{Mg}$ , ${}^{27}{Al}$ , and ${}^{28}{Si}$

( $p, d {}^{3}{He}$ ) reaction as a quasifree reaction process

$0^{+}$ and $1^{+}$ states in ${}^{24}{Na}$

Gamma-ray angular distribution measurements from the ${}^{162, 164}{Dy} (n, n^{'} γ)$ reactions

Reduced transition probabilities of vibrational states in ${}^{154 - 160}{Gd}$ and ${}^{176 - 180}{Hf}$

Electromagnetic transition probabilities in ${}^{65}{Zn}$

Masses of ${}^{61}{Fe}$ and ${}^{62}{Fe}$

Gamma spectroscopy of ${}^{52}{Fe}$ , ${}^{52}{Mn}$ , and ${}^{52}{Cr}$ from $α$ + ${}^{50}{Cr}$ reactions

Compound nucleus ( $α, p$ ) and ( $p, p^{'}$ ) reactions on odd- $A$ nuclei in the Ni region

Spin and $g$ factor of the 40-keV level in ${}^{45}{Ti}$

Level structure of ${}^{57}{Mn}$ from a ${}^{55}{Mn} (t, p) {}^{57}{Mn}$ reaction study and a mixed-configuration shell model calculation

Single-neutron transfer to ${}^{29}{Si}$ , ${}^{41, 49}{Ca}$ , and ${}^{55}{Fe}$ states induced by the ( ${}^{18}O$ , ${}^{17}O$ (g.s.)) and ( ${}^{18}O$ , ${}^{17}O$ (0.87 MeV)) reactions

Spectroscopic information from the ${}^{9}{Be}$ ( ${}^{7}{Li}$ , ${}^{6}{He}$ ) ${}^{10}B$ and ${}^{9}{Be}$ ( ${}^{7}{Li}$ , ${}^{6}{Li}$ ) ${}^{10}{Be}$ reactions

Deformed $\frac{9}{2^{+}}$ proton-hole states in odd- $A$ I nuclei

Mass of ${}^{19}N$

Gamma-ray spectroscopic studies on high-spin states in ${}^{71}{As}$ and ${}^{73}{As}$ using heavy-ion reactions

Spin-flip transitions caused by ${}^{6}{Li}$ inelastic scattering and a microscopic $α$ -spectator model

Apparent puzzles in the analyses of the ${}^{30}{Si}$ ( ${}^{16}O$ , ${}^{15}N$ ) ${}^{31}P$ reaction data

Filter

Recent Issues

Filter

Article Lookup

Enter a citation