Study of low-lying levels in 47Ca with the 48Ca(d, t)47Ca reaction

Angular distributions of cross sections [α(θ)] and vector analyzing powers [iT₁₁(γ)] have been measured for seven low-lying states or groups of states excited by the ⁴⁸Ca($\text{d}$, t)⁴⁷Ca reaction with 13.5 MeV deuterons and analyzed by the DWBA. On the basis of comparison of vector analyzing powers with DWBA calculations, spin-parity assignments have been made or confirmed for several states. Spectroscopic factors have been extracted. Angular distributions for weak states at 3.30 and 3.57 MeV excitation in ⁴⁷Ca could not be reproduced by DWBA calculations. Investigations of compound nucleus and multi-step contributions to the cross sections and analyzing powers for these states have been made by means of Hauser-Feshbach and CCBA calculations. Optical model parameters were obtained from analysis of 13.5 MeV deuteron elastic scattering cross sections and analyzing powers.     

Differential cross section,analyzing power and phase shifts for p-3He elastic scattering below 1.0 MeV

Differential cross sections and analyzing powers for the elastic scattering of polarized protons by unpolarized ³He nuclei have been measured at eight energies between 0.3 MeV and 1.0 MeV for scattering angles θ_c.m. = 52.4°–173.3°. The cross-section values were normalized to the Rutherford cross section for proton-krypton scattering. The analyzing powers have been measured with a statistical accuracy of about 0.001. The phase-shift analysis based on these data included all phases for orbital angular momenta l ≦ 1 and the channel-spin mixing parameter for the P waves. An energy parametrization of the phase shifts by an effective-range approximation allowed a simultaneous utilization of all data.     

Observation of deuteron D-state and compound nucleus effects in (d,p) reactions on 46Ti and 52Cr with a polarized deuteron beam

The cross section and the vector and tensor analyzing powers have been measured for ⁴⁶Ti(d, p)⁴⁷Ti at deuteron energies of 6 and 10 MeV and ⁵²Cr(d, p)⁵³Cr at 6 MeV. Transitions were observed to the states at E_x=0.159, 1.549 and 1.793 MeV in ⁴⁷Ti and the states at E_x=0.0, 0.564, 1.006 and 2.321 MeV in ⁵³Cr. In addition, the cross sections and vector analyzing powers for deuteron elastic scattering were measured for the same targets and deuteron energies and compared to optical model calculations. The choice of optical parameters for the DWBA analysis of the (d, p) reactions is discussed. Calculations made with the DWBA method show that the deuteron D-state must be included to reproduce even qualitatively the (d, p) tensor analyzing power measurements. The j-dependence of the tensor analyzing power T₂₂ is discussed. The validity of the local energy approximation (which was used to incorporate the deuteron D-state into the DWBA calculations) is evaluated by comparison to finite range calculations. The contribution of compound nucleus reactions to the measured cross sections and analyzing powers was investigated. In order to determine the compound cross section, the Ericson fluctuations in excitation functions of cross section and vector analyzing power were measured from 5 to 7 MeV on each target. The formulas used to calculate the polarization observables from the Hauser-Feshbach theory are presented.     

Tensor interactions and polarization phenomena in heavy-ion scattering

Elastic and inelastic scattering of ⁷Li by ⁵⁸Ni at E_lab = 14.2 and 20.3 MeV is investigated theoretically, special emphasis being laid on polarization phenomena. A parameter-independent study shows second-rank tensor interactions to be the main origin of tensor analyzing powers for both elastic and inelastic scattering. Coupled-channel (CC) calculations using cluster-folding interactions which include the tensor terms are found to be successful in reproducing the data for cross sections and vector and tensor analyzing powers, when projectile excitation effects are sufficiently taken into account. Scattering of ⁶Li by ⁵⁸Ni at E_lab = 20.0 MeV is also investigated by the CC calculation, where successes similar to the ⁷Li case are obtained in understanding experimental data.     

Spectroscopic characterization and laser performance of diode-laser-pumped Nd: GdVO4

We have carried out a detailed spectroscopic characterization of Nd: GdVO₄, a new laser crystal with high effective absorption and emission cross sections. The accidental degeneracy of the upper⁴ F _3/2 laser level decreases the number of emission lines and creates -together with the anisotropic crystal field - high emission cross sections (7.6 × 10^–19 cm² at 1.06 µm and 300 K). In addition, the lines are strongly homogeneously broadened (1.6 nm for the 808.4 nm diode-laser pump transition). The temperature dependences of lifetime, linewidths, and cross sections have been determined. Slope efficiencies up to 57% with respect to the absorbed diode-laser pump power and output powers up to 0.8 W have been achieved at 1.06 µm from a 2 mm long crystal. Intracavity second-harmonic generation, using a KTP crystal, is demonstrated.     

Analyzing power measurements for the 13C(p,d)12C reaction at 200 and 400 MeV

Cross sections and analyzing powers for the ¹³C($\text{p}$,d) reaction have been measured at 200 and 400 MeV to the 0⁺, ground state and 2⁺, 4.44 MeV state of ¹²C. While the cross sections are rather structureless, DWBA calculations in exact finite range account well for both the magnitude and shape of the angular distributions. On the other hand, the measured analyzing powers are in serious disagreement with the DWBA calculations.     

Analyzing power of the neutron continuum spectrum for the 93Nb(→p, nX) reaction at 65 MeV and a DWBA analysis

The analyzing power of neutron continuum spectrum for the ⁹³Nb($\text{→p}$, nX) reaction at 65 MeV was measured for a wide angular range ?_n = 20° – 130°. The analyzing powers are positive and large at large angles ?_n > 40°. The characteristic features in the analyzing power for the ⁹³Nb($\text{→p, nX}$) reaction are very similar to those for the ⁹³Nb($\text{→p}$, p'X) reaction indicating the importance of a common reaction mechanism for both reactions. A DWBA calculation was performed and compared with the data. The calculation for E_X = 14 MeV reproduced the cross sections but failed to reproduce the analyzing powers.     

The 90,92Zrd(p,p′) reactions at Ep = 800 MeV+

Angular distributions of analyzing powers and differential cross sections have been measured for elastic and inelastic scattering of 800 MeV protons from ⁹⁰Zr and ⁹²Zr. The data have been interpreted using both the collective-model distorted-wave Born approximation and the semimicroscopic distorted-wave impulse approximation with the Love and Franey t-matrix. Clear differences in the data for transitions to both the 2⁺₁ and the 4⁺ states in the two nuclei, attributable to differences in the microscopic structures of the states, have been observed. These differences are only partially explained by the semimicroscopic analyses. Interpreting the A_y data with the help of recent data-to-data relations suggests that the free L · S interaction used at 800 MeV is incorrect.     

The influence of deformations of the optical potential on analyzing power and p1−γ angular correlation in the reaction 114Cd(p,p′)

Differential cross sections, analyzing powers and in-plane p₁?γ angular correlations for the reaction ¹¹⁴Cd(p,p′) were measured and analysed in terms of coupled channels in order to study the influence of the quadrupole deformation of the central and the spin-orbit part of the optical potential.     

Analyses of inelastic proton scattering from 20Ne

Differential cross sections and analyzing powers for inelastic proton scattering to the 2⁺₁, 4⁺₁ and 6⁺₁ states of ²⁰Ne are analyzed using an antisymmetrized distorted wave approximation in direct reaction theory. The spectroscopy of these states was obtained by angular momentum projection from an axially symmetric minimal-energy Hartree-Fock intrinsic state.     

54Cr, 54, 58Fe, 58Ni(d,p)55Cr, 55, 59Fe, 59Ni Vector analyzing power measurements

(d, p) cross sections and vector analyzing powers have been measured at 10 MeV bombarding energy for targets ⁵⁴Cr, ⁵⁴Fe, ⁵⁸Fe and ⁵⁸Ni. The systematic behaviour of the analyzing powers with Q for states of a given J^π has been observed. Spins of a number of states in ⁵⁵Cr and ⁵⁹Fe have been deduced.     

Polarized proton inelastic scattering from 40Ca and 48Ca at 500 MeV

Differential cross sections and analyzing powers for inelastic scattering of 500 MeV polarized protons to several low-lying states in ⁴⁰Ca and ⁴⁸Ca are presented. Phenomenological optical potentials (including density squared terms) have been determined and the data have been analyzed to obtain mass deformation parameters. It is expected that these data will be useful in further testing the recently developed relativistic impulse approximation formalisms and in studying the need for medium modification of the interaction.     

A study of the 91Zr(d,p)92Zr reaction using vector-polarized deuterons

Differential cross sections and vector analyzing powers were measured for the ⁹¹Zr($\text{d}$, d)⁹¹Zr and ⁹¹Zr($\text{d}$, p)⁹²Zr reactions at an incident deuteron energy of 12 MeV. Deuteron optical-model parameters were determined from an analysis of the elastic data. Comparison of the proton data to DWBA predictions showed that the DWBA does not quantitatively reproduce the measured analyzing powers, hence empirical analyzing power calibration curves were required to analyze the data. New spectroscopic information about the configurations of the excited states in ⁹²Zr has been determined and is compared to the results of previous experiments as well as a shell-model calculation. The results of this experiment are in quantitative agreement with the predictions of the shell-model calculation for most of the transitions although some discrepancies do exist.     

Study of the structure of light,unstable nuclei and the mechanism of elastic proton scattering

The review presents calculations of elastic p ⁶He-, p ⁸Li-, p ⁹Li- and p ⁹C scattering in the framework of the Glauber theory of multiple diffraction scattering at intermediate energies of 70 and 700 MeV/nucleon. The most significant result of the calculations is that we have utilized realistic three-body wave functions obtained within modern nuclear models. The relation is found between differential cross sections and intercluster potentials, where the nuclear wave functions are calculated. Conclusions are made concerning the types of potentials which describe most realistically the available experimental data. The method for calculation of three-body wave functions in α-n-n-, α-t-n-, ⁷Be-p-p-, α-t-2n-, and ⁷Li-n-n models is described with discussion of inter-cluster potentials and the quantum-number configurations taken into consideration. It is revealed how the wave functions and the nuclear electromagnetic characteristics calculated using these wave functions depend on the choice of intercluster potentials. The derivation of matrix elements (amplitudes) of pA scattering in the framework of the Glauber approach with three-body wave functions is presented by an example of ⁶He nucleus. Discussing the results of calculation of differential cross sections and the analyzing power (A _y ), we established how the calculated characteristics depend on a wave-function structure and dynamics of the process determined by a Glauber operator of multiple scattering. The calculated differential cross sections and analyzing powers are compared with available experimental data and calculations by other authors performed for different formalisms, which allows us to make justified conclusions.     

Description of spin-dependent observables in elastic proton-deuteron scattering on the basis of a generalized diffraction model

Spin-dependent observables of elastic proton-deuteron (pd) scattering at intermediate energies are considered on the basis of calculations within a generalized diffraction model. The generalization in question takes into account all ten helicity proton-proton (pp) and proton-neutron (pn) amplitudes constructed on the basis of a present-day partial-wave analysis and precise deuteron wave functions derived from two alternative models of nucleon-nucleon (NN) forces. Explicit relations between the invariant amplitudes of pd scattering and input NN helicity amplitudes are found. Among other things, these relations make it possible to reconstruct unknown pn amplitudes at energies above 1 GeV on the basis of data on pd scattering. The predictions of the generalized diffraction model for differential cross sections and analyzing powers are compared with the latest experimental data. Surprisingly good agreement with experimental data over a broad interval of scattering angles is found both for differential cross sections and for vector and tensor analyzing powers.     

Proton-proton scattering above 3 GeV/c

A large set of data on proton-proton differential cross sections, analyzing powers and the double-polarization parameter A_NN is analyzed employing the Regge formalism. We find that the data available at proton beam momenta from 3GeV/c to 50GeV/c exhibit features that are very well in line with the general characteristics of Regge phenomenology and can be described with a model that includes the $ \rho$ \rho , $ \omega$ \omega , f₂, and a₂ trajectories and single-Pomeron exchange. Additional data, specifically for spin-dependent observables at forward angles, would be very helpful for testing and refining our Regge model.     

Measurement of the 2H(p,n) Breakup Reaction at 170 MeV and the Three-Nucleon Force Effects

The effects of three nucleon force (3NF) have been actively studied via the nucleon–deuteron (Nd) scattering states. The differential cross sections and the vector analyzing powers A _y of the ²H(p, n) inclusive breakup reaction at 170 MeV were measured for the study of 3NF effects in the intermediate energy region. The polarized proton beam of 170 MeV was injected to the deuterated polyethylene (CD₂) target and the energy of scattered neutrons were measured by using TOF method. The data were compared with the Faddeev calculations based on modern nucleon–nucleon (NN) forces with and without the 3NF. Concerning the differential cross sections, we can see large discrepancies between the data and the calculations in the region of scattered neutron energies are low, which is similar to the results of the ²H(p, p) inclusive breakup reaction at 250 MeV.