Recent Articles

Heavy-ion elastic scattering at high energies

W. L. Wang and R. G. Lipes

Phys. Rev. C 9, 814 (1974) - Published 1 March, 1974

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We investigate relativistic heavy-ion scattering in terms of a coherent droplet model, where the colliding nuclei are treated as droplets of nuclear matter with no internal structure. The interaction between nuclei is assumed to be proportional to the amount of interpenetrating matter. We take the matter distribution from electron scattering experiments, and relate the interaction parameter by the optical theorem to the total cross section. We have performed calculations at incident kinetic energies of 2.1 GeV/nucleon for ${}^{4}{He}$ , ${}^{12}C$ , and ${}^{16}O$ , and obtain a general diffraction pattern in the differential cross section. We also show an interesting scaling property of heavy-ion scattering, as compared to particle-nucleus or black-sphere scattering.

[NUCLEAR REACTIONS ${}^{4}{He}$ , ${}^{12}C$ , ${}^{16}O$ high-energy elastic heavy-ion scattering, coherent-droplet model and optical model.]

Odd-even absorption and Coulomb-exchange effects in the ${}^{3}{He}$ + ${}^{4}{He}$ and ${}^{3}H$ + ${}^{4}{He}$ systems

J. A. Koepke, Ronald E. Brown, Y. C. Tang, and D. R. Thompson

Phys. Rev. C 9, 823 (1974) - Published 1 March, 1974

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Differential cross sections for ${}^{3}{He}$ + ${}^{4}{He}$ elastic scattering are calculated at c.m. energies up to 44.5 MeV using the one-channel resonating-group method. A phenomenological imaginary potential, whose strength depends on whether the relative orbital angular momentum is even or odd, is included in the calculation in order to account approximately for open reaction channels. Exchange terms which arise from the nucleon-nucleon Coulomb interaction also are included. The introduction of both the odd-even absorption and the Coulomb-exchange terms is found to lead to significantly improved agreement with experiment. In addition, the use of improved rms matter radii for ${}^{3}{He}$ and ${}^{3}H$ is found to yield ${}^{2}P_{J}$ bound-state energies for the ${}^{3}{He}$ + ${}^{4}{He}$ and ${}^{3}H$ + ${}^{4}{He}$ systems which are more consistent with experiment than found previously.

[NUCLEAR STRUCTURE, REACTIONS ${}^{7}{Li}$ , ${}^{7}{Be}$ ; calculated ${}^{2}P_{J}$ , ${}^{2}F_{J}$ levels. ${}^{4}{He}$ ( ${}^{3}{He}$ , ${}^{3}{He}$ ), $E_{c . m .} = 1.7 - 44.5$ MeV; calculated $σ (Θ)$ ; deduced imaginary-potential strength, space-exchange mixture. Resonating-group method.]

Detection of neutron-excess isotopes of low- $Z$ elements produced in high-energy nuclear reactions

J. D. Bowman, A. M. Poskanzer, R. G. Korteling, and G. W. Butler

Phys. Rev. C 9, 836 (1974) - Published 1 March, 1974

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A search was made for new isotopes of the elements lithium through nitrogen produced in the high-energy (4.8-GeV) proton irradiation of a uranium target. The fragments were identified by $Δ E - E$ and time-of-flight techniques. An electronic pulse-width discriminator greatly reduced the background allowing high sensitivity. A new method for analyzing time-of-flight data and a new algorithm for particle identification were introduced. Two new isotopes, ${}^{14}{Be}$ and ${}^{17}B$ , were observed to be particle stable and the existence of ${}^{19}C$ was confirmed. It was shown that ${}^{12}{Li}$ and ${}^{16}B$ are particle unbound. Approximate production cross sections were determined for ${}^{14}{Be}$ , ${}^{17}B$ , ${}^{18}C$ , and ${}^{19}C$ , and upper limits estimated for ${}^{13}{Li}$ , ${}^{19}B$ , ${}^{20}C$ , and ${}^{22}N$ .

[NUCLEAR REACTIONS $U (p, x)$ , $E = 4.8$ GeV; ${}^{14}{Be}$ , ${}^{17}B$ , ${}^{18}C$ , ${}^{19}C$ measured $σ$ ; ${}^{13}{Li}$ , ${}^{19}B$ , ${}^{20}C$ , ${}^{22}N$ $σ$ upper limits.]

[NUCLEAR STRUCTURE ${}^{14}{Be}$ , ${}^{17}B$ , ${}^{19}C$ observed particle bound; ${}^{12}{Li}$ , ${}^{16}B$ particle unbound.]

Optical model with angular-momentum-dependent absorption, exchange of two nucleons, and the scattering of ${}^{16}O$ on ${}^{18}O$ near the Coulomb barrier

C. K. Gelbke, R. Bock, and A. Richter

Phys. Rev. C 9, 852 (1974) - Published 1 March, 1974

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The properties of the optical model with angular-momentum-dependent absorption are studied mainly using the scattering of ${}^{16}O$ on ${}^{18}O$ for energies near the Coulomb barrier. The results have been compared to two-nucleon transfer predictions. The $L$ -dependent form factor has been taken as $f (L) = {1 + \exp [\frac{(L - L_{C})}{Δ L_{C}}]}^{- 1}$ . The following have been found: (1) There exists an approximate continuous ambiguity concerning the parameters $L_{C}$ and $Δ L_{C}$ which implies a simplification with respect to practical calculations. (2) The $L$ cutoff in the imaginary potential produces an $L$ staggering of the reflection coefficients similar to the one by the exchange model. (3) Both models yield a different energy dependence of the $L$ staggering, since the oscillations of the reflection coefficients are, in the $L$ -dependent optical model, connected with size resonances; in the case of exchange, however, with the symmetry of the reaction and the bound-state wave function of the exchanged particle.

[NUCLEAR REACTIONS heavy-ion scattering ${}^{16}O$ on ${}^{18}O$ ; two-nucleon exchange; deduced optical model with angular-momentum-dependent absorption.]

Exchange potential between "nearly" identical nuclei

Tetsuyuki Yukawa

Phys. Rev. C 9, 864 (1974) - Published 1 March, 1974

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In the framework of the microscopic theory of complex collisions the interaction between "nearly" identical nuclei, two nuclei which have nearly the same mass and whose common states of the core are to be considered identical, has been studied. The couplings between the elastic and other channels are neglected except those between different polarizations. The existence of the space-exchange potential is shown as the results of the core-exchange process as well as the exchange of valence particle(s). A simple model calculation has been done for the ${}^{16}O$ + ${}^{17}O$ system. The nature of the long-range part of the potential, especially the polarization dependence of the coupling potential, and the physical consequence of the space-exchange potential in the elastic scattering differential cross section are discussed.

[NUCLEAR STRUCTURE ${}^{16, 17}O$ ; calculated HI potential. Harmonic-oscillator shell model, Pauli exchange, $P$ dependence.]

High-lying neutron-hole states populated in the reaction ${}^{13}C (p, d) {}^{12}C$ at 62 MeV

L. J. Parish, R. A. Brown, K. A. Eberhard, A. Richter, and W. von Witsch

Phys. Rev. C 9, 876 (1974) - Published 1 March, 1974

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The single-nucleon pickup reaction ${}^{13}C (p, d) {}^{12}C$ at 62 MeV has been employed to study high-lying states in ${}^{12}C$ . States are seen at excitation energies $E_{x} = 17.76, 18.80, 21.5, and 22.5$ MeV in ${}^{12}C$ and the $1 p$ neutron-hole strength found is in qualitative agreement with theoretical predictions. However, the $1 p$ neutron-hole strength at high excitation is distributed over more states than predicted by intermediate-coupling shell-model calculations.

Separable potentials for the nucleon-nucleon ${}^{3}S_{1} - {}^{3}D_{1}$ channel

Steven C. Pieper

Phys. Rev. C 9, 883 (1974) - Published 1 March, 1974

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Separable potentials of rank one to five for the nucleon-nucleon ${}^{3}S_{1} - {}^{3}D_{1}$ channel are constructed using a method introduced by Ernst, Shakin, and Thaler. The potentials all have the same deuteron wave function as the Reid soft-core potential. In addition the phase shifts of the rank-four and -five potentials are quite close to the experimental phase shifts. A survey of previously published separable potentials of rank greater than one is made and it is concluded that most of these potentials have unacceptably poor deuteron properties. A number of errors that were made in the fitting of these potentials to the data are pointed out. A simplification of the Reid soft-core potential for the ${}^{3}S_{1} - {}^{3}D_{1}$ channel is also presented. The simplified potential consists entirely of Yukawa terms but has experimental properties that generally differ from the original Reid soft-core properties by less than the present experimental error.

[NUCLEAR REACTIONS Separable potentials fitted to Reid ${}^{3}S_{1} - {}^{3}D_{1}$ phase shifts, deuteron wave function. Previous ${}^{3}S_{1} - {}^{3}D_{1}$ separable potentials surveyed, errors pointed out. Compared to UPE constructions. Simplified (local) Reid tensor force presented.]

Separable-interaction model for $pd$ elastic scattering

Jon M. Wallace

Phys. Rev. C 9, 897 (1974) - Published 1 March, 1974

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This paper is the third in a series in which we develop an exactly soluble three-nucleon model for describing medium-energy $Nd$ scattering processes. The model, which is an out-growth of the three-nucleon model of Aaron, Amado, and Yam, has been successful in describing deuteron breakup reactions through 156 MeV. It is here applied to elastic scattering. Calculations of $pd$ elastic cross sections at 31, 40, 46.3, 77, 95, and 146 MeV are carried out and compared with experiment. The model describes elastic angular distributions adequately at the lower energies considered. However, at the higher energies the model is somewhat less successful over at least part of the angular range than it is for lower-energy elastic scattering or for breakup throughout this energy range. We attribute this to the rather crude character of the $pn$ input at higher energies, which manifests itself more clearly in the elastic cross sections.

[NUCLEAR REACTIONS ${}^{2}H (p, p)$ , $E = 31 - 146$ MeV; calculated $σ (θ)$ .]

Identification of analog pairs in ${}^{13}C$ and ${}^{13}N$ by means of the ${}^{10}B$ ( ${}^{6}{Li}$ , ${}^{3}{He}$ ) ${}^{13}C$ and ${}^{10}B ({}^{6}{Li}, t) {}^{13}N$ reactions

Charles H. Holbrow, H. G. Bingham, R. Middleton, and J. D. Garrett

Phys. Rev. C 9, 902 (1974) - Published 1 March, 1974

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The ${}^{10}B ({}^{6}{Li}, t) {}^{13}N$ and ${}^{10}B ({}^{6}{Li}, {}^{3}{He}) {}^{13}C$ reactions were induced with $E_{{}^{6}{Li}} = 18$ MeV in order to test the assignment of mirror pairs by direct comparison of the resulting spectra. The technique appears to be reliable up to excitations of ∼ 10 MeV for these cases. Some new analog pairs are suggested, and a hitherto unreported state is identified at 9.00 MeV in ${}^{13}N$ .

[NUCLEAR REACTIONS ${}^{10}B ({}^{6}{Li}, t)$ , ${}^{10}B ({}^{6}{Li}, {}^{3}{He}) E = 18$ MeV; measured energy levels, $σ (θ)$ ; identified $J$ , $π$ and analog pairs of states in ${}^{13}N$ and ${}^{13}C$ .]

Study of $T = \frac{3}{2}$ states in ${}^{17}F$

B. M. Skwiersky, C. M. Baglin, and P. D. Parker

Phys. Rev. C 9, 910 (1974) - Published 1 March, 1974

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The first seven $T = \frac{3}{2}$ states in ${}^{17}F$ have been studied as resonances in the ${}^{16}O + p$ entrance channel, observing the ( $p_{0}$ ), ( $p_{1} + p_{2}$ ), ( $p_{3} + p_{4}$ ), and ( $α_{0}$ ) exit channels. In a survey of the energy region $E_{p} = 13.23 to 16.60$ MeV in steps of less than 5 keV at six laboratory angles, the previously unobserved fourth and fifth $T = \frac{3}{2}$ states were found at $E_{p} = 13.271 \pm 0.004 and 14.017 \pm 0.004$ MeV, respectively. Complete elastic scattering angular distributions (at 29 angles from $θ_{lab} = 25$ to 165°) were measured from $E_{p} = 9.0 to 20.35$ MeV in 50-keV steps and were analyzed using the optical-model code JIB3 to extract phase-shift information across this region. These results were used in a phase-shift analysis of the individual $T = \frac{3}{2}$ resonances to obtain the following assignments for the second through the seventh $T = \frac{3}{2}$ states in ${}^{17}F$ : ${E_{p} (MeV), E_{x} ({}^{17}F) (MeV), Γ (keV), \frac{Γ_{p_{0}}}{Γ}, J^{π}} {12.708 \pm 0.004 12.551 3 \pm 1, 0.26 \pm 0.04 {\frac{3}{2}}^{-}} {13.250 \pm 0.004 13.061 2 \pm 1, 0.15 \pm 0.04 {\frac{5}{2}}^{-}} {13.271 \pm 0.004 13.080 2 \pm 1, 0.04 \pm 0.02 ({\frac{1}{2}}^{+})} {14.017 \pm 0.004 13.782 12 \pm 5, 0.02 \pm 0.01 {\frac{5}{2}}^{+}} {14.438 \pm 0.006 14.177 27 \pm 5, 0.04 \pm 0.02 {\frac{3}{2}}^{-}} {14.579 \pm 0.010 14.310 20 \pm 5, 0.11 \pm 0.03 {\frac{7}{2}}^{-}}$

[NUCLEAR REACTIONS ${}^{16}O (p, p)$ , $(p, α) E = 9.0 - 20.4$ MeV; measured $σ (E; θ)$ ; deduced optical-model parameters. Phase-shift analysis; ${}^{17}F (T = \frac{3}{2})$ levels as compound-nucleus resonances; deduced $E_{x}$ , $Γ$ , $\frac{Γ_{p_{0}}}{Γ}$ , $J^{π}$ .]

Neutron-proton polarization measurements near 20-MeV incident neutron energy

C. L. Morris, T. K. O'Malley, J. W. May, Jr., and S. T. Thornton

Phys. Rev. C 9, 924 (1974) - Published 1 March, 1974

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Using the ${}^{3}H (d, \vec{n}) {}^{4}{He}$ reaction as a source of polarized neutrons, measurements of the $n - p$ polarizations have been made at 16.9 and 21.1 MeV. Results are reported at 40, 60, 80, and 140° c.m. for both energies as well as at 100 and 120° c.m. for 21.1 MeV. Comparisons are made with predictions of the LRL-X and the YALE-IV phase-shift analysis. The data favor the LRL-X analysis at forward angles and the YALE-IV analysis at backward angles.

[NUCLEAR REACTIONS ${}^{1}H (\vec{n}, n)$ , $E = 16.9 and 21.1$ MeV, measured $P (θ)$ .]

Compound nature of the reaction ${}^{12}C$ ( ${}^{14}N$ , ${}^{6}{Li}$ ) ${}^{20}{Ne}$

D. L. Hanson, R. G. Stokstad, K. A. Erb, C. Olmer, and D. A. Bromley

Phys. Rev. C 9, 929 (1974) - Published 1 March, 1974

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It is found that the statistical model accounts rather well for the absolute cross sections measured recently for the reaction ${}^{12}C$ ( ${}^{14}N$ , ${}^{6}{Li}$ ) ${}^{20}{Ne}$ at $E_{c . m .} \sim 24 and \sim 36$ MeV and for the integrated ${}^{7}{Be}$ yields observed in the ${}^{12}C$ + ${}^{14}N$ reaction at $E_{c . m .} = 16 - 28$ MeV. These results demonstrate that compound-nucleus formation followed by the emission of complex particles such as ${}^{6}{Li}$ or ${}^{7}{Be}$ occurs with sizable cross sections in these reactions.

[NUCLEAR REACTIONS ${}^{12}C$ + ${}^{14}N$ compound reactions, complex particle emission, statistical model calculations. ${}^{12}C$ ( ${}^{14}N$ , ${}^{6}{Li}$ ), $E_{c . m .} = 24, 36$ MeV, calculated $σ (θ)$ ; $E_{c . m .} = 36, 55$ MeV, calculated ${}^{6}{Li}$ evaporation spectra shapes. ${}^{12}C ({}^{14}N, 2 p)$ , ( ${}^{14}N, α$ ) ( ${}^{14}N, {}^{7}{Be}$ ), $E_{lab} = 12 - 60$ MeV; calculated integrated yields.]

Parity-violating asymmetry in nucleon-nucleon scattering

Virginia R. Brown, Ernest M. Henley, and Franz R. Krejs

Phys. Rev. C 9, 935 (1974) - Published 1 March, 1974

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The weak parity-violating component of the nucleon-nucleon interaction can be studied directly and in detail through the scattering of longitudinally polarized nucleons on nucleons. We use distorted-wave theory to predict the dependence of the differential and total cross sections on the helicity of incident longitudinally polarized protons for elastic proton-nucleon scattering at energies up to ∼ 300 MeV. The weak force used is parametrized by $ρ$ , $ω$ , $π$ , and $2 π$ exchanges, the strong one by a Hamada-Johnston or Bryan-Gersten potential.

[NUCLEAR REACTIONS Weak nucleon-nucleon force. Calculate parity-violating asymmetry for longitudinally polarized nucleon-nucleon scattering.]

$μ^{-} + {}^{6}{Li} \to {}^{3}H + {}^{3}H + ν$ with final-state interactions

B. R. Wienke and S. L. Meyer

Phys. Rev. C 9, 943 (1974) - Published 1 March, 1974

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The capture $μ^{-} + {}^{6}{Li} \to {}^{3}H + {}^{3}H + ν$ is briefly reanalyzed using the current-current theory of weak interactions and a scattering representation for the final-state interactions between the outgoing tritons. Both the capture rate and symmetrized triton-energy distribution are estimated using asymptotic triton wave functions with nuclear phase shifts-obtained from a resonating-group analysis of the ditriton system. We obtain a rate $Γ = 141$ $\sec^{- 1}$ .

[NUCLEAR REACTIONS ${}^{6}{Li} (μ^{-}, ν) {}^{3}H {}^{3}H$ , $E = 0$ , calculated $σ$ , symmetrized triton distribution. Current-current interaction. DWBA.]

In-beam measurement of $E 0$ matrix element in ${}^{72}{Se}$ and ${}^{72}{Ge}$

James E. Draper, Nicholas S. P. King, and Walter G. Wyckoff

Phys. Rev. C 9, 948 (1974) - Published 1 March, 1974

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A 0 + state in ${}^{72}{Se}$ at 936 keV has been identified through in-beam measurements with ${}^{70}{Ge} (α, 2 n) {}^{72}{Se}$ . The beam-related time distribution of conversion electrons from the 936-keV $E 0$ transition yields a half-life of 19.3±0.4 ns. With a ${}^{72}{Ge}$ target and an $α$ -beam sweeper the half-life of the 690-keV $E 0$ transition in ${}^{72}{Ge}$ was 404±45 ns. For both transitions identification of the emitting nucleus was obtained from the energy separation of the $K$ and $L$ electrons. The $\frac{K}{L}$ intensity ratio was intermediate between the theoretical results of Hager and Seltzer and those of Church and Weneser. The reduced $E 0$ nuclear matrix elements are $ρ = (0.304 \pm 0.003) (1 - 5.01 \times 10^{- 3} f)$ and $ρ = 0.095 \pm 0.005$ for ${}^{72}{Se}$ and ${}^{72}{Ge}$ , respectively, which are 0.77 (for $f ≲ 40$ ) and 0.24, respectively, of Wilkinson's suggested single-particle unit for $E 0$ matrix elements. The $f$ is the 0′→2 enhancement.

[NUCLEAR REACTIONS ${}^{70}{Ge} (α, 2 n)$ , $E = 27.5$ MeV, ${}^{72}{Ge} (α, α^{'})$ and ${}^{72}{Ge} (α, p n)$ , $E = 27.5$ MeV; measured in-beam ce spectra and time distributions; deduced $T_{\frac{1}{2}}$ and $E 0$ matrix element for 936-keV 0+ state in ${}^{72}{Se}$ and 690-keV 0+ state in ${}^{72}{Ge}$ ; compared $\frac{K}{L}$ ratio with theories.]

High-spin states in ${}^{39}K$ from ${}^{24}{Mg} ({}^{18}O, p 2 n γ γ \dots) {}^{39}K$

J. J. Kolata, Ph. Gorodetzky, J. W. Olness, A. R. Poletti, and E. K. Warburton

Phys. Rev. C 9, 953 (1974) - Published 1 March, 1974

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The electromagnetic decays of several high-spin states in ${}^{39}K$ were studied via heavy-ion-induced reactions involving ${}^{18}O$ and ${}^{19}F$ bombardments of targets of ${}^{24}{Mg}$ , ${}^{26}{Mg}$ , and ${}^{27}{Al}$ . The ${}^{39}K$ states were formed most strongly in the ${}^{24}{Mg} ({}^{18}O, p 2 n γ γ \dots) {}^{39}K$ reaction which provided the main body of quantitative evidence we report. The identification of specific transitions in ${}^{39}K$ , and the resultant decay scheme, are based on Ge(Li) $γ - γ$ coincidence spectra and also on $γ$ -ray yield curves measured for $20 \leq E_{B} \leq 61$ MeV. Lifetimes of ${}^{39}K$ states were measured by the recoil distance method. These lifetimes together with $γ$ -ray angular distributions restrict the allowable spin-parity assignments and multipole mixing ratios for the transitions studied. Arguments based on the proposed reaction mechanism are invoked to give a most probable decay scheme for the high-spin states involved. The resulting data provide new information on the high-spin structure of ${}^{39}K$ and also illustrate the power of these heavy-ion-induced compound-nucleus reactions as spectroscopic tools for the investigation of high-spin states in light nuclei.

[NUCLEAR REACTIONS ${}^{24}{Mg} ({}^{18}O, p 2 n γ γ \dots)$ , $E = 20 - 61.5$ MeV; $σ (E, E_{γ})$ , $γ γ$ coin; deduced ${}^{39}K$ levels, tabulated and identified 120 $γ$ rays from ${}^{24}{Mg}$ + ${}^{18}O$ at 40 MeV; measured $σ (E_{γ}, θ)$ , $T_{\frac{1}{2}}$ for ${}^{39}K$ transitions; deduced $Λ$ for transitions and $J^{π}$ , $δ$ for high-spin ${}^{39}K$ levels.]

( ${}^{6}{Li}, d$ ) reaction on ${}^{40}{Ca}$

U. Strohbusch, C. L. Fink, B. Zeidman, R. G. Markham, H. W. Fulbright, and R. N. Horoshko

Phys. Rev. C 9, 965 (1974) - Published 1 March, 1974

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The ${}^{40}{Ca} ({}^{6}{Li}, d) {}^{44}{Ti}$ reaction was studied at $E ({}^{6}{Li}) = 32$ MeV. Angular distributions for ${}^{44}{Ti}$ levels up to 9-MeV excitation energy have been measured. They are compared with $α$ -transfer distorted-wave Born-approximation calculations to determine angular momentum transfers and relative strengths.

[NUCLEAR REACTIONS ${}^{40}{Ca} ({}^{6}{Li}, d)$ , $E = 32$ MeV measured $σ (θ)$ , levels. ${}^{44}{Ti}$ levels, ZR DWBA deduced $l$ , $J_{f}$ , $π$ , $S$ .]

Gamma production cross sections from 14-MeV neutron bombardment of ${}^{89}Y$

F. S. Dietrich, M. C. Gregory, and J. D. Anderson

Phys. Rev. C 9, 973 (1974) - Published 1 March, 1974

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$γ$ decays of levels in ${}^{88}Y$ and ${}^{89}Y$ have been observed with a Ge(Li) spectrometer following 14.1-MeV neutron bombardment of natural yttrium metal. Prompt and delayed (> 50 nsec) radiations were separated by pulsing the neutron source. Following the reaction ${}^{89}Y (n, 2 n) - {}^{88}Y$ , delayed $γ$ rays of 442 and 232 keV are ascribed to the decay sequence $8^{+}$ (674 keV) → $5^{-}$ (232) → $4^{-}$ (0) and a 393-keV $γ$ ray to the transition $1^{+}$ (393) → $4^{-}$ (0). A delayed 909-keV radiation corresponds to the decay of the first excited state of ${}^{89}Y$ . Cross sections were determined with an uncertainty of ± 11% for the delayed radiations and ± 30% for the remainder. A statistical-model calculation for the ${}^{89}Y (n, 2 n) {}^{88}Y$ reaction reproduces the observed cross sections only if the $γ$ branching ratios in ${}^{88}Y$ are taken from experiment, and in particular, the ${(g_{\frac{9}{2}})}^{2}$ multiplet is included.

[NUCLEAR REACTIONS ${}^{89}Y (n, 2 n γ) {}^{88}Y$ , ${}^{89}Y (n, n^{'} γ) {}^{89}Y$ . $E = 14.1$ MeV; measured $E_{γ}$ , $σ (E_{γ})$ . Deduced $σ (E_{γ})$ dependence on $J$ , $π$ in ${}^{88}Y$ . Natural target, Ge(Li) detector.]

Absolute $γ$ -ray intensities in the decay of ${}^{79}{Kr}$ and ${}^{127}{Xe}$

R. Collé and R. Kishore

Phys. Rev. C 9, 981 (1974) - Published 1 March, 1974

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Absolute $γ$ -ray intensities in the decay of ${}^{79}{Kr}$ and ${}^{127}{Xe}$ have been determined from sources which were produced by ( $p, n$ ) reactions on encapsulated potassium-halide targets. Absolute $γ$ -ray emission rates of these sources were first measured with several calibrated Ge(Li)-detector systems. Then, following separation of the ${}^{79}{Kr}$ or ${}^{127}{Xe}$ gas, absolute disintegration rates of the sources were obtained by counting internally in gas proportional counters. Comparisons of the present results with previous work are made and although there are no major discrepancies, several inconsistencies in the existing decay schemes are resolved and the uncertainties in the absolute $γ$ -ray intensities are substantially reduced. The half-lives for ${}^{79}{Kr}$ and ${}^{127}{Xe}$ were measured by both gas proportional counting and $γ$ -ray spectrometry and are 35.04±0.10 h and 36.3±0.3 day, respectively.

[RADIOACTIVITY ${}^{79}{Kr}$ , ${}^{127}{Xe}$ ; measured $T_{\frac{1}{2}}$ , $E_{γ}$ , absolute $I_{γ}$ .]

Microscopic, nonharmonic description of rotations and pairing vibrations in deformed $pf$ -shell nuclei

K. Allaart, K. Goeke, H. Müther, and A. Faessler

Phys. Rev. C 9, 988 (1974) - Published 1 March, 1974

Show Abstract

Angular-momentum- and particle-number-projected self-consistent Hartree-Bogoliubov wave functions are used within the generator-coordinate method for the description of excited states in ${}^{48}{Ti}$ and ${}^{56}{Fe}$ . Bands based on the ground state and first pairing-vibrational state respectively are studied. In the ground band of ${}^{56}{Fe}$ an antipairing effect occurs parallel with an increase of correlations in the excited band, so that for higher $J$ the ground band becomes less paired than the excited one.

[NUCLEAR STRUCTURE ${}^{48}{Ti}$ , ${}^{56}{Fe}$ ; calculated rotational spectra. Hartree-Bogoliubov, generator-coordinate method, $J$ projection.]

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Physical Review C

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Heavy-ion elastic scattering at high energies

Odd-even absorption and Coulomb-exchange effects in the ${}^{3}{He}$ + ${}^{4}{He}$ and ${}^{3}H$ + ${}^{4}{He}$ systems

Detection of neutron-excess isotopes of low- $Z$ elements produced in high-energy nuclear reactions

Optical model with angular-momentum-dependent absorption, exchange of two nucleons, and the scattering of ${}^{16}O$ on ${}^{18}O$ near the Coulomb barrier

Exchange potential between "nearly" identical nuclei

High-lying neutron-hole states populated in the reaction ${}^{13}C (p, d) {}^{12}C$ at 62 MeV

Separable potentials for the nucleon-nucleon ${}^{3}S_{1} - {}^{3}D_{1}$ channel

Separable-interaction model for $pd$ elastic scattering

Identification of analog pairs in ${}^{13}C$ and ${}^{13}N$ by means of the ${}^{10}B$ ( ${}^{6}{Li}$ , ${}^{3}{He}$ ) ${}^{13}C$ and ${}^{10}B ({}^{6}{Li}, t) {}^{13}N$ reactions

Study of $T = \frac{3}{2}$ states in ${}^{17}F$

Neutron-proton polarization measurements near 20-MeV incident neutron energy

Compound nature of the reaction ${}^{12}C$ ( ${}^{14}N$ , ${}^{6}{Li}$ ) ${}^{20}{Ne}$

Parity-violating asymmetry in nucleon-nucleon scattering

$μ^{-} + {}^{6}{Li} \to {}^{3}H + {}^{3}H + ν$ with final-state interactions

In-beam measurement of $E 0$ matrix element in ${}^{72}{Se}$ and ${}^{72}{Ge}$

High-spin states in ${}^{39}K$ from ${}^{24}{Mg} ({}^{18}O, p 2 n γ γ \dots) {}^{39}K$

( ${}^{6}{Li}, d$ ) reaction on ${}^{40}{Ca}$

Gamma production cross sections from 14-MeV neutron bombardment of ${}^{89}Y$

Absolute $γ$ -ray intensities in the decay of ${}^{79}{Kr}$ and ${}^{127}{Xe}$

Microscopic, nonharmonic description of rotations and pairing vibrations in deformed $pf$ -shell nuclei

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