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Out of plane measurements of the angular correlations for the 12C(e, e(')n) reaction have been performed for the first time in the giant resonance region. The cross sections were directly separated into the longitudinal and transverse, longitudinal-transverse, and transverse-transverse components. The cross section at the peak of the giant resonance ( omega = 22.5 MeV) has been found to be almost all longitudinal. It was reproduced by the multipole expansion with E0 and E2 components besides E1. The longitudinal-transverse component might have a maximum around 24 MeV. The transverse-transverse component is very small over the giant resonance.

Angular correlations for the {sup 12}C(e,e{sup {prime}}n){sup 11}C reaction in the giant resonance region have been measured for forward scattering at an effective momentum transfer of 0.35fm{sup -1}. The angular correlation for the ground-state transition indicates a strong forward-backward asymmetry at the peak of the giant dipole resonance ({omega}=22.5MeV), which is different from the nearly symmetric angular correlations observed for the {sup 12}C(e,e{sup {prime}}p{sub 0}){sup 11}B reaction. Recent random-phase approximation predictions fail to reproduce the experimental angular correlations for both (e,e{sup {prime}}n{sub 0}) and (e,e{sup {prime}}p{sub 0}), predicting the opposite patterns to those observed. {copyright} {ital 1997} {ital The American Physical Society}

Low-lying states in {sup 56}Fe, up to an excitation energy of about 4 MeV, have been investigated by means of inelastic proton and deuteron scattering experiments at {ital E}{sub {ital p}}=65 and 400 MeV and at {ital E}{sub {ital d}}=56 MeV, respectively. Measured cross sections and analyzing powers have been compared with coupled-channels calculations using collective form factors; calculations in both the Schr{umlt o}dinger and Dirac formalisms have been carried out for the proton data. For each probe, the matrix elements have been deduced for transitions from the ground state and from the 2{sub 1}{sup +} state to six quadrupole (2{sup +}) states to one octupole (3{sub 1}{sup {minus}}) and two hexadecapole (4{sub 1}{sup +} and 4{sub 2}{sup +}) states. The obtained matrix elements and the previous values from {gamma} decay or electron inelastic scattering have been used to evaluate the isospin character of the transitions. To discuss the quadrupole mixed-symmetry states in {sup 56}Fe, the deduced neutron ({ital M}{sub {ital n}}) and proton ({ital M}{sub {ital p}}) components of the matrix elements, or equivalently the isoscalar ({ital M}{sub {ital s}}) and isovector ({ital M}{sub {ital v}}) parts, have been compared with theoretical calculations based on the neutron-proton interacting bosonmore » model and on the shell model evaluated in a full {ital f}-{ital p} configuration space. {copyright} {ital 1996 The American Physical Society.}« less

Decay neutrons from the [sup 40]Ca([ital e],[ital e][prime][ital n])[sup 39]Ca reaction were studied in the giant resonance region. The cross sections and angular distributions, separated for [ital n][sub 0] and [ital n][sub 1] decays, were obtained for excitation energies between 19 and 27 MeV, at the effective momentum transfer of 0.35 fm[sup [minus]1]. Legendre polynomial coefficients obtained from fitting the data are compared with those from the ([ital e],[ital e][prime][ital p]) reaction. In the energy range 19--21 MeV, the interference coefficients [ital b][sub 1] and [ital b][sub 3] for the ground state transition are in agreement, but the noninterference coefficient [ital b][sub 2] is different. The different behavior of the angular distribution for protons and neutrons may suggest the interference of the decay from a [ital T]=0 quadrupole resonance and the [ital T]=1 giant dipole resonance. A similar tendency was also seen in comparing with the ([ital e],[ital e][prime][ital p][sub 1]) reaction. The Legendre polynomial coefficients for the [ital n][sub 0] decay in the ([ital e],[ital e][prime][ital n]) reaction, transformed to the photon point, agree well with those of the ([gamma],[ital n][sub 0]) reaction. The reduced total cross section is consistent between the ([ital e],[ital e][prime][ital n]) and ([gamma],[ital n])more » reactions, but the cross section for ([ital e],[ital e][prime][ital n][sub 0]) is larger than that of ([gamma],[ital n][sub 0]) near the peak of the resonance. The values of the longitudinal-transverse interference term are close to zero in the present region, which is rather small compared with the value near the resonance of the ([ital e],[ital e][prime][ital p]) reaction.« less

Proton single-particle states in $^{21,23}\mathrm{Na}$ were studied through the (d,n) reaction on $^{20,22}\mathrm{Ne}$ at ${\mathit{E}}_{\mathit{d}}$=25 MeV. Angular distributions of the emitted neutrons leading to the final states up to ${\mathit{E}}_{\mathit{x}}$=15 MeV were measured. Spectroscopic information has been obtained from an analysis with the adiabatic deuteron breakup approximation, where s-wave deuteron breakup effects have been included. Proton unbound transitions were analyzed by means of Vincent and Fortune's method. It was found that the observed proton single-particle states in $^{21,23}\mathrm{Na}$ exhausted almost all the strength for the 2s1d shell. The distributions of the 2s1d strength were reasonably reproduced by recent 2s1d shell model calculations. The occupation probabilities and single-particle energies of the proton orbits near Fermi levels in the ground states of $^{20,22}\mathrm{Ne}$ were deduced in a framework of combined analysis of the stripping and pickup data on the same target nucleus.

Differential cross sections for the 9Be(d, n)10B reaction have been measured at Ed=25 MeV using the time-of-flight technique. Experimental angular distributions for the states below Ex=6.57 MeV were analysed with the distorted-wave theory including the S-wave deuteron-breakup effects in the adiabatic approximation. The extracted spectroscopic factors were compared with previous data. Coupled-reaction-channel (CRC) calculations were also performed, and significant improvements were seen for weakly excited states.

The 16O( p , p ′ ) reaction was studied with a 35 MeV polarized proton beam. The cross sections and analyzing powers for excited states in 16O up to and including the 2−, T = 1 state at 12.97 MeV were measured and compared with DWBA calculations. Both density-independent and densitydependent effective interactions were used in the calculations. Transition densities calculated using shell-model amplitudes and Woods-Saxon single-particle wave functions give poor accounts of the data. The use of macroscopic transition densities obtained from electron scattering data give a much better description of the data, especially when used in combination with the densitydependent interaction.

The 14C(p, t)12C reaction leading to the states in 12C in the region of excitation energy Ex = 0–19 MeV was studied at Ep = 40.3 MeV. The data were analyzed within the framework of exact-finite-range first and second-order DWBA calculations using Op-shell-model wave functions. The transitions to the T = 0 states of natural parity were found to require 3 times more enhancement than those to the T = 1 states. Angular distributions of cross sections for the 1+ states were reproduced by including two-step processes such as (p-d-t) and (p, t) (t, t'), but their absolute values were underestimated in the present analysis. The (p, t) transitions to the 3− and 4+ states, which are forbidden by the direct pickup process in the Op-shell-model space, were also investigated. The transition to the α-cluster-like 7.65 MeV 0+2 state was explained reasonably by a multistep process via the 4.44 MeV 2+ state of 12C.

Cross sections for the neutron pickup reaction 14C(p, d)13C were measured at Ep = 35.0 MeV for the states below E = 10 MeV, and at Ep = 40.1 MeV for the states between Ex = 11 and 18 MeV. Obtained angular distributions were compared with exact finite-range DWBA calculations to extract spectroscopic factors. Second-order DWBA calculations were also made in some cases. Almost full 0p 1 2 strength was found, while the observed 0p 3 2 strength was 80% of the simple sum-rule limit. The main part of the remaining strength was found in the 0d 5 2 orbit, and, in a lesser degree, in the 1s 1 2 and 0d 3 2 orbits. Small fractions of the 0f 5 2 and Og 9 2 strengths were also necessary to explain the angular-distribution shapes and the cross-section magnitudes of the predominantly multistep transitions to the 5− 2 and 5+ 2 states.

Angular correlations and cross sections for the {sup 40}Ca(e,e{sup '}n){sup 39}Ca reaction have been measured in the continuum above the giant resonance. A comparison of the missing energy spectra between the peak and the tail regions of the giant resonance indicates that neutron emission in the peak region leads to populating the ground and first excited states, whereas emission in the tail region leads to populating excited states at an energy about 4.5 MeV higher. The latter seems to be because of the 2s{sub 1/2} and 1d{sub 5/2} hole excitation, that is core excitation. The same tendency was observed in the {sup 28}Si(e,e{sup '}n){sup 27}Si reaction of the sd shell nuclei but it did not appear as clearly in the {sup 12}C(e,e{sup '}n){sup 11}C reaction of the 1p shell nuclei.

Proton single-particle strengths in ${}^{19}\mathrm{F}$ were investigated up to an excitation energy of 14 MeV through the $(d,n)$ reaction on ${}^{18}\mathrm{O}$ at ${E}_{d}=25$ MeV. Spectroscopic strengths were deduced from adiabatic-deuteron-breakup-approximation analysis. Most of the strengths for the $2s1d$-shell orbitals were observed in the present measurement. Strength distributions were compared with the shell-model predictions in the framework of the complete $2s1d$-shell basis. Results for the ${1d}_{5/2}$ and ${2s}_{1/2}$ strengths were in good agreement with the shell-model calculation, but the theoretical estimate for the ${1d}_{3/2}$ strength did not reproduce the observation. The occupation probabilities and single-particle energies of proton orbitals near the Fermi surface for ${}^{18}\mathrm{O}$ were evaluated from a combined analysis of the present stripping data and previous proton pickup data.

Optical absorption spectra concerning 4f /spl rarr/ 5d transition of Ce/sup 3+/-doped solid-state laser crystals were calculated by ab-initio fully relativistic molecular orbital method. In Ce/sup 3+/:LiYF/sub 4/, importance of yttrium atoms was pointed out for assignment of the spectrum.

Recently, instabilities and chaos in a single-mode CO2 laser with a saturable absorber (LSA) have attracted much attention as a direct access to nonlinear dynamics, such as Shil'nikov chaos and Feigenbaum's period-doubling scenario [1,2]. Introduction of extra lasing modes may bring novel aspects into the laser dynamics and largely extend applicability of the LSA as a model of dynamical systems.

The density-dependent interaction based on the Bonn-J\"ulich G-matrix NN interaction was used in a distorted-wave Born approximation analysis of (p,p') and (p,n) data for p-shell nuclei at ${\mathit{E}}_{\mathit{p}}$=35 MeV. Calculations with this interaction fit the data as well as the commonly used density-independent interaction M3Y and gave significant improvement for analyzing powers of unnatural-parity transitions. Most of the improvement was found to be due to the tensor part of the interaction.

Effects of inelastic multistep processes on (p, t) reactions in a transition region between well-deformed rare-earth nuclei and the double-magic 208 Pb have been investigated by the 188 Os(p, t) 186 0s, 194, 196 Pt(p, t) 192, 194 Pt and 200, 202 Hg(p, t) 198, 200 Hg reactions at E p = 51.9 MeV. The observed ground 0 + , first excited 2 + and 4 + angular distributions together with those for the 206, 208 pb(p, t) 204, 206 pb reactions have been compared with CCBA and DWBA calculations, using transfer form factors based on the Nilsson, vibrational and shell models. It is found that the inelastic multistep processes play a very important role in reproducing both the shapes and magnitudes of the observed first excited 2 + angular distributions, contrasting to small contributions in the ground-state 0 + transitions. The effects of the inelastic multistep processes on the first excited 4 + transitions are also considered to be important.

The giant-resonance region in $^{92}\mathrm{Zr}$ has been studied by inelastic electron scattering of the effective momentum transfer range $0.65\ensuremath{\le}{q}_{\mathrm{eff}}\ensuremath{\le}1.18$ ${\mathrm{fm}}^{\ensuremath{-}1}$. The high-energy octupole resonance was identified at ${E}_{x}=25\ifmmode\pm\else\textpm\fi{}0.3$ MeV with a width of 6.3\ifmmode\pm\else\textpm\fi{}0.3 MeV exhausting 39\ifmmode\pm\else\textpm\fi{}4% of the $T=0$ $E3$ energy weighted sum rule. This result is in good agreement with a recent ($^{3}\mathrm{He}$, $^{3}\mathrm{He}$') result and the recent random-phase approximation calculations, and its strength is inconsistent with the trend of low strength of the high-energy octupole resonances observed by inelastic proton scattering.NUCLEAR REACTIONS $^{92}\mathrm{Zr}$(e,e'), enriched target, ${E}_{0}=220$ MeV, $\ensuremath{\theta}=32\ifmmode^\circ\else\textdegree\fi{}\ensuremath{-}61\ifmmode^\circ\else\textdegree\fi{}$, $q=0.65\ensuremath{-}1.18$ ${\mathrm{fm}}^{\ensuremath{-}1}$. Measured $\frac{{d}^{2}\ensuremath{\sigma}}{d\ensuremath{\Omega}d{E}_{x}}$ up to 33 MeV in excitation energy; deduced excitation energy, width, sum rule exhaustion of isoscalar high-energy octupole resonance.

Bumps of two-hole states at high excitation energies were observed systematically in the triton spectra from (p, t) reactions with 52 MeV protons on nuclei in a broad range of masses. The cross sections of the bumps are almost equal for various targets with the same deep major shells. These cross sections vary discontinuously with variation of the corresponding deep major shell. About 20 to 50 % of the total expected strength is observed experimentally, if the bumps are assumed to arise from two-neutron pickup from the deep major shells. The centres of gravity of the bumps are located at excitation energies of about 7 to 9 MeV in all cases. On the other hand, the widths of the bumps change from about 3 MeV for 66 Zn to about 9 MeV for 230 Th.

The 46,48,50Ti(d,3He)45,47,49Sc reactions have been investigated at an incident energy of 52 MeV. Angular distributions have been measured and spectroscopic factors have been deduced by means of a DWBA analysis. Positive-parity states have been found up to about 9 MeV excitation energy, revealing about 70% of the 1d5/2 proton-hole strength. The 2s1/2, 1d3/2 and 1d5/2 strength distributions are compared with predictions from phonon-hole coupling calculations.

Continuous triton energy spectra from the ( 3 He, t) reaction of 9 Be were measured and well explained by the four-body breakup process including Coulomb penetrability. The integrated cross section of the continuum between 10° and 90° is of the order of 15 mb at E 3 He =6.70 MeV.

Excitation curves for the products of the Be9+p reaction and several angular distributions for the Be9(p, α0)Li6 and Be9(p, d0)Be8 reactions have been measured for bombarding energies from 1.00 to 4.60 MeV. Showing the typical behaviours for direct reaction mechanism, the results have been compared with the pick-up theory in plane-wave Born approximation.

An investigation of the decay scheme of K 44 has been made with anthracene- and 5''×5'' NaI(Tl)-scintillation counters, and coincidence techniques. In addition to the 4.91-, 3.55- and 2.63-MeV beta rays, the following gamma rays has been assigned to Ca 44 : 0.48-, 0.63-, 0.74-, 0.90-, 1.06-, 1.16-, 1.5-, 1.74-, 2.08-, 2.17-, 3.4-, 4.4-, 4.6- and 5.0-MeV. A decay scheme is proposed.

Evidence for the proximity 3 He(n, p) 3 H reaction in the final state of the sequential 6 Li(d, 3 He) 5 He(n) 4 He process was observed. The behaviour of the positions of the peaks in the two-dimensional spectra was consistent with kinematical predictions. It should be emphasized that the proximity scattering was extended to a rearrangement process. The strength of the process gave direct information on the lifetime of the ground state of 5 He. A classical estimate led to τ = 1.4 × 10 −21 sec, which is the shortest nuclear lifetime directly measured. The consistency of this value with the level width gives quantitative support for the occurrence of the proximity reaction.

The 91 Zr( p , t ) 89 Zr reaction has been studied by using 51.7-MeV protons in order to obtain informations on reaction mechanism. Emitted tritons were analyzed by a broad range magnetic spectrometer with a 200-channel counter array. Angular distributions of the tritons were obtained for the thirteen states in 89 Zr. They were compared with the DWBA calculations in which a new formalism for form factors was used. Calculated patterns of the angular distributions for the lowest four one-neutron hole states in 89 Zr less fitted the experimental results in comparison with the case for the higher states. Absolute values of the observed cross sections for the formers agreed with the calculated ones within a factor 2, but were strongly enhanced for the latters.

The bremsstrahlung spretra of the 8.5-Mev electrons for the forward direction were measured with a scintillation spectrometer with a sodium iodide crystal 4 in. in diameter and 4 in. in length. Be, Ni, and Pt of several thickness were used as the targets. The measured spectra were compared with our semiempirical calculation. The calculation was based upon the response function for NaI crystal which was constructed referring to the method developed by NBS group and also to the actual response curve for the monochromatic gammas of 1.12 and 6.14 Mev, instead of using Monte Carlo method which had generally been used in the former researches. The agreement is rather good if Schiff's formula for the intrinsic bremsstrahlung spectra is assumed. (auth)

10 intermediate resonances with their spins and parities were identified in this study. The average width is 160 \ifmmode\pm\else\textpm\fi{} 60 keV, which is consistent with the value 153 keV predicted by Hsu's relationship.NUCLEAR REACTION $^{28}\mathrm{Si}(d,p)$, $E=2.0\ensuremath{-}4.2$ MeV; measured $\ensuremath{\delta}(E;\ensuremath{\theta})$; $\ensuremath{\theta}=15\ensuremath{-}165\ifmmode^\circ\else\textdegree\fi{}$, $\ensuremath{\Delta}\ensuremath{\theta}=15\ifmmode^\circ\else\textdegree\fi{}$; channel correlation analysis; discussed intermediate structure.

In peeling off the thin target material from glass plate, which was prepared by vacuum-evaporation, glucose was used instead of Teepole. The advantages of this method are described.

The 90 deg yields of gamma radiation produced from proton capture by Al/ sup 27/ were measured at proton energies of 7.5 to 14.5 Mev. The relative cross section data combined with these of Canberra revealed a giant resonance of width on the order of 4 Mev and with many peaks. Three resonances at 7.61, 8.75, and 10.13 Mev can be attributed to the excited state of Si/sup 28/. The giant resonance is interpreted from the standpoint of spheroidal deformation of a compound nucleus. (D. L.C.)

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