Recent Articles

Systematics of reaction cross sections and interaction barriers for charged particles

Louis C. Vaz and John M. Alexander

Phys. Rev. C 10, 464 (1974) - Published 1 August, 1974

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Experimentally determined total reactin cross sections $σ_{R}$ have been used to obtain the systematics of interaction barriers in reactions between charged nuclei. The real potential was assumed to be parabolic at its maximum and hence the characteristic parameters are barrier height, radius, and curvature, $E_{0}$ , $R_{0}$ , and $ℏ ω_{0}$ , respectively. Barrier heights and radii follow clear systematic trends and therefore these systematics can be used to predict total reaction cross sections for energies close to and greater than the barrier. Experimental data for incident energies below the barrier are sparse and therefore they cannot be well systematized at this time. The cross section patterns for low incident energies seem to reflect individuality of the collision partners.

NUCLEAR REACTIONS Total cross sections $σ_{R}$ for charged particle reactions are systematized in terms of a real inverted parabolic barrier. Graphical interpolation and extrapolation of the interaction barrier $E_{0}$ permit prediction of $σ_{R}$ .

Proton-proton bremsstrahlung: Coulomb effect

Leon Heller and Marvin Rich

Phys. Rev. C 10, 479 (1974) - Published 1 August, 1974

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A nonrelativistic potential model calculation of proton-proton bremsstrahlung is carried out in which the Coulomb potential as well as double scattering are treated exactly. The conventional electromagnetic current operator for point protons with charge and magnetic moment is used. Cross sections differential with respect to the photon angle are calculated in the symmetric, coplanar Harvard geometry for proton angles of 10, 20, and 30°, at laboratory energies of 5, 20, 42, 62, 99, and 158 MeV, using the Hamada-Johnston potential. Cross sections integrated over the photon angle are presented over a wider range of angles. Including the Coulomb potential lowers the cross section by amounts which are comparable with the errors of the most accurate experiments, and at proton angles smaller than any of the existing experiments the Coulomb effect becomes quite large. Cross sections for the asymmetric Orsay experiment are also computed, including the effect of noncoplanarity, and there is a large discrepancy at some of the experimental points.

NUCLEAR REACTIONS $p (p, p γ)$ ; calculated $σ (θ_{γ})$ for lab proton energies 5 to 158 MeV, including Coulomb effects.

Polarization and polarization transfer in the reaction ${}^{3}H (p, n) {}^{3}{He}$ at 5.97 and 9.9 MeV

J. J. Jarmer, R. C. Haight, J. C. Martin, and J. E. Simmons

Phys. Rev. C 10, 494 (1974) - Published 1 August, 1974

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Angular distributions of the polarization transfer coefficients $K_{x}^{x^{'}} (θ)$ , $K_{z}^{x^{'}} (θ)$ , $K_{y}^{y} (θ)$ , and the polarization $P (θ)$ in the reaction ${}^{3}H (p, n) {}^{3}{He}$ have been measured for proton energies of 5.97 and 9.9 MeV. The measurements of polarization transfer were done with an incident polarized proton beam. The polarizations of the neutrons were measured with a liquid helium polarimeter. Comparisons are made with $R$ -matrix calculations based on the levels of ${}^{4}{He}$ from the analysis of Werntz and Meyerhof.

NUCLEAR REACTIONS ${}^{3}H (p, n) {}^{3}{He}$ , $E = 5.97 and 9.9$ MeV; measured polarization $P (θ)$ , and polarization transfer $K_{x}^{x^{'}} (θ)$ , $K_{z}^{x^{'}} (θ)$ , and $K_{y}^{y} (θ)$ .

Accuracy of the distorted-wave impulse approximation for breakup reactions in a three-body model

Stephen K. Young and Edward F. Redish

Phys. Rev. C 10, 498 (1974) - Published 1 August, 1974

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We have studied the reaction mechanisms of the ( $p, 2 p$ ) reaction on ${}^{4}{He}$ at energies of 65 and 100 MeV. The dynamics of the reaction is taken to be that of a three-particle system, the ${}^{4}{He}$ target being viewed as a proton bound to an inert triton. The particles interact via separable potentials chosen to fit bound state and scattering data of the two-particle subsystems. The protons are treated as identical bosons interacting with each other only in the relative $S$ state while the proton-triton potential is limited to relative $L \leq 2$ . The ${}^{4}{He} (p, 2 p) {}^{3}H$ doubly differential cross section can be calculated exactly within this model by solving the Faddeev equations numerically using the method of deformed contours and Padé approximants. This can be compared with the distorted-wave impulse approximation (DWIA), calculated in this model by summing the appropriate subset of the multiple scattering series. This is done in momentum space and treats off-shell and finite range effects of the nucleon-nucleon $T$ matrix as well as recoil effects exactly. We find that the DWIA is an adequate approximation at 100 MeV but is almost double the exact result at 65 MeV. Its use in the extraction of spectroscopic information below 100 MeV is therefore suspect. The shapes of the exact, distorted, and plane wave cross sections agree quite well with each other (and with the experimental shape), differing only in magnitude.

NUCLEAR REACTIONS ${}^{4}{He} (p, 2 p) {}^{3}H$ , $E = 65, 100$ MeV; calculated $σ$ . Threebody model, reaction mechanisms.

Elastic proton scattering from ${}^{3}{He}$ and ${}^{4}{He}$ and the ${}^{4}{He} (p, d) {}^{3}{He}$ reaction at 85 MeV

L. G. Votta, P. G. Roos, N. S. Chant, and R. Woody, III

Phys. Rev. C 10, 520 (1974) - Published 1 August, 1974

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Differential cross sections for the elastic scattering of protons by ${}^{3}{He}$ and ${}^{4}{He}$ , and for the ${}^{4}{He} (p, d) {}^{3}{He}$ reaction were measured at an incident energy of 85 MeV. The elastic scattering cross sections have been compared with phenomenological optical model calculations which yield good fits to the experimental data, provided that a Majorana exchange term is included in the optical potential. The ${}^{4}{He} (p, d) {}^{3}{He}$ data show qualitative agreement with distorted-wave Born-approximation calculations. In addition the experimental data are compared to resonating group theory calculations; one channel calculations for the elastic scattering, and two channel calculations for the ${}^{4}{He} (p, d) {}^{3}{He}$ reaction. These resonating group calculations are in qualitative agreement, and generally reproduce the important features of the experimental data.

NUCLEAR REACTIONS ${}^{3}{He} (p, p)$ , ${}^{4}{He} (p, p)$ , and ${}^{4}{He} (p, d)$ , $E = 85.0$ MeV measured $σ (θ)$ , enriched targets.

Proton-induced deuteron breakup at 156 MeV

J. P. Didelez, I. D. Goldman, E. Hourany, H. Nakamura, F. Reide, and T. Yuasa

Phys. Rev. C 10, 529 (1974) - Published 1 August, 1974

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The ${}^{2}H (p, 2 p) n$ and ${}^{2}H (p, p n) p$ reactions have been investigated simultaneously using the 156 MeV synchrocyclotron beam. Outgoing nucleons were detected in coincidence by a NaI detector and a large liquid scintillation counter providing energy-time-of-flight-biparametric spectra from which the threefold differential cross sections $\frac{d^{3} σ}{d Ω_{1} d Ω_{2} d E_{1}}$ are deduced. For suitable angle pairs, the experimental spectra show either the characteristic quasi-free scattering peak, or the $p - p$ or $p - n$ final state interaction peaks. The experimental results are compared with various theoretical predictions; i.e., a simple spectator model calculation, off-energy-shell calculations including first and second order terms of a multiple scattering series, with or without the Coulomb interaction, and extension to intermediate energy of a Amado type model. These theoretical calculations are briefly discussed.

NUCLEAR REACTIONS ${\frac{d^{3} σ}{d Ω_{1} d Ω_{2} d E_{1}})}_{\exp}$ for ${}^{2}H (p, 2 p)$ and ${}^{2}H (p, p n)$ reactions at 156 MeV. Studies of $p - n$ and $p - p$ final state interactions. The comparison with some theoretical approximate calculations discussed.

Center-of-mass effects in single-nucleon knock-out reactions

A. E. L. Dieperink and T. de Forest, Jr.

Phys. Rev. C 10, 543 (1974) - Published 1 August, 1974

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Angular distributions for the ${}^{9}{Be}$ ( ${}^{6}{Li}$ , ${}^{7}{Li}$ ) ${}^{8}{Be}$ reaction

P. L. Von Behren, E. Norbeck, and G. L. Payne

Phys. Rev. C 10, 550 (1974) - Published 1 August, 1974

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Angular distributions for the ${}^{9}{Be}$ ( ${}^{6}{Li}$ , ${}^{7}{Li}$ ) ${}^{8}{Be}$ neutron-transfer reaction to form the lowest two states in ${}^{7}{Li}$ have been measured for laboratory energies of 5.5 and 6.5 MeV. Elastic scattering cross sections for ${}^{6}{Li}$ on ${}^{9}{Be}$ were measured at laboratory energies of 4.0 and 6.0 MeV in order to determine optical potentials for the theoretical analysis of the transfer cross section. Distorted-wave-Born-approximation calculations were found to be in reasonable agreement with the data while Hauser-Feshbach calculations were not. This indicates that the reaction is primarily a direct process.

NUCLEAR REACTIONS ${}^{9}{Be}$ ( ${}^{6}{Li}$ , ${}^{7}{Li}$ ), $E = 5.5, 6.5$ MeV; measured $σ (θ)$ ${}^{7}{Li}$ states at 0.0, 0.48 MeV; DWBA analysis. ${}^{9}{Be}$ ( ${}^{6}{Li}$ , ${}^{6}{Li}$ ), $E = 4, 6$ MeV; measured $σ (θ$ ; deduced optical-model parameters.

Reexamination of the ${}^{24}{Mg} (d, p) {}^{25}{Mg}$ reaction for $E_{d} = 10 - 15$ MeV

T. A. Schmick, K. W. Kemper, P. K. Bindal, and R. D. Koshel

Phys. Rev. C 10, 556 (1974) - Published 1 August, 1974

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Complete angular distributions (18-165° c.m.) have been measured for the first six proton groups from the ${}^{24}{Mg} (d, p) {}^{25}{Mg}$ reaction and for the reaction ${}^{24}{Mg} (d, d_{0, 1}) {}^{24}{Mg}$ at $E_{d} = 14 and 15$ MeV to provide data to study multistep contributions to the transfer reactions with emphasis on the " $j$ -forbidden" transition to the ${\frac{7}{2}}^{+}$ (1.611 MeV) state of ${}^{25}{Mg}$ . To assess compound nuclear contributions, excitation functions were taken with $E_{d} = 10 - 14$ MeV for the first six proton groups from the ${}^{24}{Mg} (d, p) {}^{25}{Mg}$ reaction. The excitation functions indicate significant amounts of nondirect structure for $E_{d} < 13$ MeV in all the reaction channels. Optical model, Hauser-Feshbach, standard distorted wave Born approximation (DWBA), and perturbative multistep calculations of the data have been performed. Comparison of the Hauser-Feshbach calculations with the 14 and 15 MeV data imply that compound contributions are negligible for all of the reaction channels except the " $j$ -forbidden" channel. The multistep calculations give somewhat better agreement with the experimental results than do the DWBA calculations; however, the multistep calculations must be renormalized for each state and each bombarding energy, indicating an incomplete description of the data.

NUCLEAR REACTIONS ${}^{24}{Mg} (d, p)$ , measured $σ (E)$ at 60, 80, 100, 120° for $E = 10 - 14$ MeV. Measured $σ (θ)$ at 14 and 15 MeV; $θ = 18 - 165 °$ , $Δ θ = 5 °$ . DWBA and multistep DWBA analysis, deduced $S$ . ${}^{24}{Mg} (d, d_{0, 1})$ measured $σ (θ)$ at 14 and 15 MeV; $θ = 18 - 165 °$ , $Δ θ = 5 °$ .

n ${}^{6}{Li} (α, d) {}^{8}{Be}$ reaction and the importance of exchange processes

M. B. Greenfield, M. F. Werby, and R. J. Philpott

Phys. Rev. C 10, 564 (1974) - Published 1 August, 1974

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The ${}^{6}{Li} (α, d) {}^{8}{Be}_{g . s .}$ reaction is studied in the expectation that exchange contributions will be enhanced relative to the more usual light particle stripping process. Angular distributions of deuterons were measured at bombarding energies of 20 and 24 MeV and are found to exhibit back-angle peaking characteristic of the exchange process. Calculations including only a direct stripping mechanism are not able to account for the back-angle peaking and disagree with the back-angle data by more than two orders of magnitude. A two-mode finite-range distorted-wave Born-approximation analysis including cluster exchange contributions accurately describes the observed backward peaking at both energies. The importance of exchange contributions is attributed to favorable kinematic conditions and large cluster amplitudes associated with the exchange process.

NUCLEAR REACTIONS ${}^{6}{Li} (α, d)$ , $E = 20, 24$ MeV; measured $σ (θ)$ , $θ = 15 ° - 175 °$ . Enriched target. Two-mode, finite range DWBA analysis. ${}^{8}{Be}$ ; calculated $α \oplus α$ radial function.

Vector and tensor analyzing-power measurements for ${}^{3}H (\vec{d}, d) {}^{3}H$ elastic scattering at 11.4 and 14.4 MeV

T. R. Donoghue, Gerald G. Ohlsen, Nelson Jarmie, and P. W. Keaton, Jr.

Phys. Rev. C 10, 571 (1974) - Published 1 August, 1974

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Angular distribution of the vector and tensor analyzing powers $A_{y}$ , $A_{xz}$ , $\frac{1}{2} (A_{xx} - A_{yy})$ , and $A_{zz}$ have been measured at 11.4 and 14.4 MeV for $d + {}^{3}H$ elastic scattering. Mass identification techniques were used in detecting the scattered deuteron and the recoil triton at most angles. Measurements were made for the 33 to 140° center-of-mass angular range. The angular distributions of the various analyzing powers are very similar at both energies and additionally are similar to the $d + {}^{3}{He}$ analyzing-power data of König et al. at 11.5 MeV.

NUCLEAR REACTIONS ${}^{3}H (\vec{d}, d) {}^{3}H$ : $E_{d} = 11.4 and 14.4$ MeV, $θ_{c . m .} = 33 - 140$ , measured vector and tensor analyzing powers.

2p-1h structure of ${}^{15}N$ from ${}^{14}C (p, p) {}^{14}C$ cross section and polarization measurements

H. R. Weller, R. A. Blue, J. J. Ramirez, E. M. Bernstein, H. R. Hiddleston, R. M. Prior, S. E. Darden, and M. Divadeenam

Phys. Rev. C 10, 575 (1974) - Published 1 August, 1974

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The cross section for the ${}^{14}C (p, p) {}^{14}C$ reaction has been measured for proton energies from 4 to 11.5 MeV. The elastic proton polarization has been measured for proton energies from 3.2 to 5.7 MeV. The region between 3.2 and 7.5 MeV has been fitted using complex background phase shifts and 14 resonances. The parameters of $E_{res}$ , $Γ$ , $Γ_{p}$ , and $J^{π}$ were obtained for the 14 resonances. The data suggest several new candidates for $T = \frac{3}{2}$ states in ${}^{15}N$ . A 2p-1h doorway state calculation shows reasonable agreement with most of the experimental results.

NUCLEAR REACTIONS ${}^{14}C (p, p) {}^{14}C$ ; measured $σ (θ)$ , $E = 4.0 - 11.5$ MeV; measured $P (θ)$ , $E = 3.2 - 5.7$ MeV. ${}^{15}N$ levels deduced $J$ , $π$ , $Γ_{p}$ , $Γ$ , $E_{res}$ . Compared experiment to 2p-1h doorway state calculation.

Multiple diffraction theory, optical potentials, and an alternative approach to high-energy scattering by nuclei

Yukap Hahn

Phys. Rev. C 10, 585 (1974) - Published 1 August, 1974

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Aformally exact perturbation expansion of the high-energy scattering amplitude by nuclei is developed, in which the leading term is given by the Glauber's multiple diffraction amplitude. The leading correction terms are examined in detail, which deal with the two approximations involved in the Glauber amplitude; (a) the linearization of the Green's function and (b) the fixed-scatterer assumption. Thus, the diffraction amplitude can be systematically improved rather simply so long as the scattering angle is not too large. It is stressed that, when the target profile function is replaced by the individual mucleon profiles, the correction to the linearization approximation is automatically included to all orders in the Glauber amplitude, insofar as the nonoverlapping interactions are concerned. The contents of the Glauber wave function are then analyzed to show explicitly that, within the approximations (a) and (b), the major part of the inelastic channel information, and thus of the optical potential, is already included in the theory. By comparing the diffraction theory with the optical potential approach, which is based on the multiple scattering theory and the conversion of the optical potential to a set of coupled equations, we exhibit a close connection between the two seemingly diverging approaches. As a result of this analysis, we derive a modified theory of high-evergy scattering by nuclei, in which the elastic component is to be treated exactly without the linearization while the inelastic component is taken directly from the diffraction theory.

NUCLEAR REACTIONS Systematic corrections to the high-energy nucleonnucleus amplitude in the multiple diffraction theory of Glauber.

Transfer versus compound-nuclear mechanism in the reaction of ${}^{12}C$ and ${}^{11}B$ with ${}^{63}{Cu}$ and ${}^{65}{Cu}$

Robert A. Williams and Albert A. Caretto, Jr.

Phys. Rev. C 10, 601 (1974) - Published 1 August, 1974

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Excitation functions and average projected ranges have been measured for the production of ${}^{66}{Ga}$ and ${}^{70}{As}$ from enriched ${}^{63}{Cu}$ and ${}^{65}{Cu}$ targets with ${}^{11}B$ and ${}^{12}C$ projectiles of 10.5 MeV/ amu. In addition, angular and range distributions were determined for the same products from ${}^{63}{Cu}$ and ${}^{65}{Cu}$ with 90 MeV ${}^{12}C$ ions. The results are compared with predictions based on the complete fusion compound nucleus mechanism and a quasielastic scattering model designed to represent transfer mechanisms. The results indicate that a number of the reactions must take place by more than one pathway.

NUCLEAR REACTIONS ${}^{65, 63}{Cu} ({}^{11}B, X) {}^{66}{Ga}$ , ${}^{65, 63}{Cu} ({}^{12}C, X) {}^{70}{As}$ , separated isotope targets, $E = 23 - 117$ MeV; measured $σ (E)$ , recoil fragment $E$ , and fragment $σ (E, θ)$ for 90 MeV ${}^{12}C$ .

Photoneutron cross sections of ${}^{58}{Ni}$ and ${}^{60}{Ni}$

S. C. Fultz, R. A. Alvarez, B. L. Berman, and P. Meyer

Phys. Rev. C 10, 608 (1974) - Published 1 August, 1974

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Photoneutron cross sections of ${}^{58}{Ni}$ and ${}^{60}{Ni}$ have been measured, using separated isotopes and nearly monoenergetic photons from in-flight annihilation of positrons. Both ( $γ, n$ ) and ( $γ, 2 n$ ) cross sections have been obtained; the ( $γ, 3 n$ ) cross section for both isotopes was found to be essentially negligible up to the highest energy measured, 33.5 MeV. The peak cross section of 27 mb for ${}^{58}{Ni}$ occurs at 17.3 MeV, while for ${}^{60}{Ni}$ the peak cross section of 74 mb occurs at 16.3 MeV. The ( $γ, 2 n$ ) cross section of ${}^{58}{Ni}$ is small, never exceeding 1.5 mb, whereas in the case of ${}^{60}{Ni}$ the ( $γ, 2 n$ ) cross section rises to a peak value of just over 10 mb at approximately 24 MeV, where it constitutes over 30% of the total photoneutron cross section. In both nuclei the ( $γ, 2 n$ ) cross section appears essentially to vanish above 33 MeV, whereas the single-neutron cross sections of both appear to remain nearly constant from about 25 MeV to the maximum measured energy. Considerable structure appears in the total cross section of both nuclei throughout the giant-resonance region. Structure is also evident in the ( $γ, 2 n$ ) cross sections, particularly in the case of ${}^{60}{Ni}$ . Integrated total photoneutron cross sections up to 33.5 MeV were determined to be 286 MeV mb for ${}^{58}{Ni}$ and 704 MeV mb for ${}^{60}{Ni}$ . Our results are compared with those from previous photoneutron experiments, and, combined with measured photoproton cross sections, are used to test theoretical predictions based on shell-model calculations.

NUCLEAR REACTIONS ${}^{58, 60}{Ni} (γ, n)$ , ( $γ, 2 n$ ), $E = 12 - 34$ MeV; measured $σ (E)$ ; deduced integrated cross sections, symmetry energies. Enriched targets, monoenergetic photons, resolution 75-160 keV.

$γ$ -ray transitions in ${}^{48}{Cr}$ and ${}^{60}{Zn}$

R. Kamermans, H. W. Jongsma, J. van der Spek, and H. Verheul

Phys. Rev. C 10, 620 (1974) - Published 1 August, 1974

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The level structure of the $N = Z = even nuclei {}^{48}{Cr} and {}^{60}{Zn}$ was investigated. The levels were excited in the ( ${}^{3}{He}, n$ ) reaction. By measuring direct $γ$ radiation in coincidence with the outgoing neutrons information about the $γ$ decay of the levels was obtained.

NUCLEAR REACTIONS ${}^{46}{Ti}$ , ${}^{58}{Ni}$ ( ${}^{3}{He}, n γ$ ), $E = 10$ MeV measured $E γ$ , $I γ$ , $n γ$ coin deduced ${}^{48}{Cr}$ , ${}^{60}{Zn}$ levels, $J$ , $π$ . Enriched targets. Ge(Li) detector.

Level structure of ${}^{129}{Ba}$ from the ${}^{130}{Ba} (d, t) {}^{129}{Ba}$ reaction

Roger D. Griffioen and Raymond K. Sheline

Phys. Rev. C 10, 624 (1974) - Published 1 August, 1974

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The level structure of ${}^{129}{Ba}$ has been investigated by means of the ${}^{130}{Ba} (d, t) {}^{129}{Ba}$ reaction using 16 MeV deuterons and a broad-range magnetic spectrograph. The $Q$ value to the lowest observed state was found to be -4001 ± 15 keV. Energies and angular distributions have been measured for 13 levels below 1.0 MeV. The lowest observed state was found to have spin and parity and of ${\frac{1}{2}}^{+}$ and a level 277 keV above this state with $l = 5$ is suggested to have $J^{π} = {\frac{11}{2}}^{-}$ . The clearly established absence of a lower lying ${\frac{7}{2}}^{-}$ level, together with the well established systematics in the $N = 75$ Nd and Ce nuclei, demonstrates that the ${\frac{11}{2}}^{-}$ state is a member of the $Ω = {\frac{9}{2}}^{-} [514]$ band.

NUCLEAR REACTIONS ${}^{130}{Ba} (d, t)$ , $E = 16$ MeV, enriched targets; measured $σ (θ)$ , $θ = 20 - 85 °$ ; measured $Q$ . ${}^{129}{Ba}$ deduced levels, $J$ , $π$ , $(2 J + 1) S$ . Coriolis coupling scheme and intermediate coupling model calculations.

Coulomb excitation and direct inelastic effects in the decay of the $5^{-}$ analog resonance in ${}^{208}{Bi}$

K. Ramavataram, S. Ramavataram, W. G. Davies, A. J. Ferguson, and J. S. Fraser

Phys. Rev. C 10, 632 (1974) - Published 1 August, 1974

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The excitation function and angular distributions of the protons from the $5^{-}$ analog resonance excited in the ${}^{207}{Pb} (p, p_{1}) {}^{207}{Pb}^{*}$ reaction have been measured and are compared with a resonance calculation that includes contributions from the inelastic and Coulomb excitation of the nucleus by adding the appropriate distorted-wave Born-approximation scattering amplitude to the Breit-Wigner resonance term. The experimental results are well reproduced by these calculations. From the fits to the elastic and inelastic scattering data, the strength of the ( $f_{\frac{5}{2}}^{- 1} g_{\frac{9}{2}}$ ) neutron particle-hole component in the parent state wave function is deduced and is found to be in good agreement with the predictions of the shell model. The reduced transition rate $B (2)$ associated with the collective (1/ $2^{-}$ -5/ $2^{-}$ ) excitation in ${}^{207}{Pb}$ is extracted.

NUCLEAR REACTION ${}^{207}{Pb} (p, p)$ , $E = 14 - 15.5$ MeV; measured $σ (E)$ , $σ (E, θ)$ , $θ = 60 - 160 °$ ; ${}^{208}{Bi}$ IAR deduced $Γ$ , $S$ ; ${}^{207}{Pb}$ level deduced $B (2)$ ; enriched targets.

Statistical model analysis for the deexcitation of ${}^{117}{Te}$ at $E^{*} = 71 and 107$ MeV in the reactions ${}^{14}N$ + ${}^{103}{Rh}$ and ${}^{40}{Ar}$ + ${}^{77}{Se}$

J. Galin, B. Gatty, D. Guerreau, U. C. Schlotthauer-Voos, and X. Tarrago

Phys. Rev. C 10, 638 (1974) - Published 1 August, 1974

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A detailed statistical model analysis is presented for the deexcitation of the compound nucleus ${}^{117}{Te}$ at excitation energies of 71 and 107 MeV being formed at both energies with large angular momenta by the reactions ${}^{14}N$ + ${}^{103}{Rh}$ and ${}^{40}{Ar}$ + ${}^{77}{Se}$ . The competition of charged particle ( $p, α$ ), neutron, and $γ$ emission is explicitly considered in the calculations for each decay step throughout the whole evaporation cascades. By this method the energy spectra of protons and $α$ particles in the four reactions can be well reproduced with respect to their form, average kinetic energies, and absolute cross sections with a consistent set of the statistical model parameters.

NUCLEAR REACTIONS ${}^{103}{Rh} ({}^{14}N, p)$ , ${}^{103}{Rh} ({}^{14}N, α)$ , ${}^{77}{Se} ({}^{40}{Ar}, p)$ , ${}^{77}{Se} ({}^{40}{Ar}, α)$ at $E_{CN}^{*} ({}^{117}{Te}) = 71 - 107$ MeV; consistent statistical model analysis of $σ (E_{particle})$ ; detailed discussion of parameters.

Evidence for ( $α, {}^{5}{He}$ ) reactions in the interaction of high-energy $α$ particles with ${}^{208}{Pb}$

C. Pirart, M. Bosman, P. Leleux, P. C. Macq, and J. P. Meulders

Phys. Rev. C 10, 651 (1974) - Published 1 August, 1974

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$α$ -neutron coincidence measurements performed on the ${}^{208}{Pb} (α, α^{'} n)$ reaction at $E_{α} = 66$ MeV show clear evidence for short-lived ${}^{5}{He}$ production. The majority of $α$ particles with energy between 40 and 51.5 MeV are assigned to the ( $α, {}^{5}{He}$ ) reaction channel.

NUCLEAR REACTIONS ${}^{208}{Pb} (α, {}^{5}{He})$ , $E = 66$ MeV; measured $α$ -neutron coincidence.

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Systematics of reaction cross sections and interaction barriers for charged particles

Proton-proton bremsstrahlung: Coulomb effect

Polarization and polarization transfer in the reaction ${}^{3}H (p, n) {}^{3}{He}$ at 5.97 and 9.9 MeV

Accuracy of the distorted-wave impulse approximation for breakup reactions in a three-body model

Elastic proton scattering from ${}^{3}{He}$ and ${}^{4}{He}$ and the ${}^{4}{He} (p, d) {}^{3}{He}$ reaction at 85 MeV

Proton-induced deuteron breakup at 156 MeV

Center-of-mass effects in single-nucleon knock-out reactions

Angular distributions for the ${}^{9}{Be}$ ( ${}^{6}{Li}$ , ${}^{7}{Li}$ ) ${}^{8}{Be}$ reaction

Reexamination of the ${}^{24}{Mg} (d, p) {}^{25}{Mg}$ reaction for $E_{d} = 10 - 15$ MeV

n ${}^{6}{Li} (α, d) {}^{8}{Be}$ reaction and the importance of exchange processes

Vector and tensor analyzing-power measurements for ${}^{3}H (\vec{d}, d) {}^{3}H$ elastic scattering at 11.4 and 14.4 MeV

2p-1h structure of ${}^{15}N$ from ${}^{14}C (p, p) {}^{14}C$ cross section and polarization measurements

Multiple diffraction theory, optical potentials, and an alternative approach to high-energy scattering by nuclei

Transfer versus compound-nuclear mechanism in the reaction of ${}^{12}C$ and ${}^{11}B$ with ${}^{63}{Cu}$ and ${}^{65}{Cu}$

Photoneutron cross sections of ${}^{58}{Ni}$ and ${}^{60}{Ni}$

$γ$ -ray transitions in ${}^{48}{Cr}$ and ${}^{60}{Zn}$

Level structure of ${}^{129}{Ba}$ from the ${}^{130}{Ba} (d, t) {}^{129}{Ba}$ reaction

Coulomb excitation and direct inelastic effects in the decay of the $5^{-}$ analog resonance in ${}^{208}{Bi}$

Statistical model analysis for the deexcitation of ${}^{117}{Te}$ at $E^{*} = 71 and 107$ MeV in the reactions ${}^{14}N$ + ${}^{103}{Rh}$ and ${}^{40}{Ar}$ + ${}^{77}{Se}$

Evidence for ( $α, {}^{5}{He}$ ) reactions in the interaction of high-energy $α$ particles with ${}^{208}{Pb}$

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