Polarization transfer in the deuteron break-up reaction at 56 MeV

The polarization transfer coefficients K^yy′ of the break-up spectra in the reactions ¹²C, ⁵⁸Ni, ²⁰⁹Bi($\text{d}$, $\text{p}$X) were measured at 56 MeV. In the forwardd angles (13.5° and 20.0°), the K_y^y′ data at the break-up peak are nearly equal to $\text{2}\text{3}$ (the spectator model prediction) and they decrease at both sides of the peak. The deviation due to the deuteron D-state is estimated, using PWBA and DWBA.     

Angular distribution of polarization transfer in 2H(d, p)3H

Measurements have been made of seven polarization transfer coefficients for the ²H($\text{d}$, $\text{p}$)³H reaction. The experiment used a polarized deuteron beam from the Los Alamos Scientific Laboratory Lamb-shift polarized ion source, a liquid-nitrogen cooled deuterium gas target, a magnetic quadrupole triplet for focusing the reaction protons and a helium filled polarimeter for simultaneously measuring the proton polarization along two transverse axes. Results have been obtained at 10 MeV and for lab angles of 15, 30, 45 and 60 degrees for the vector transfer coefficients K_x^x′, K_y^y′ and K_z^x′, and the tensor transfer coefficients K_xx^y′, K_yy^y′, K_zz^y′ and K_xz^y′.     

Longitudinal polarization transfer in the T→p, →n)3He reaction

The longitudinal polarization of neutrons has been measured for the reaction $\text{T}\text{→p}\text{,}\text{→n}\text{)}{}^3\text{He}$ with the incident proton beam longitudinally polarized. Measurements were performed at 0° for proton energies from 4 to 15 MeV and an angular distribution was measured at 10 MeV. The data determine the polarization transfer coefficient K_z^z′, which is equivalent to the Wolfenstein A′ parameter for nucleon-nucleon scattering. The quantity K_z^z′ at 0° increases from about 0.3 at 3 MeV incident energy to 0.9 at 9 MeV, and then decreases to 0.5 at 15 MeV. The data are computed with R-matrix calculations which reproduce the qualitative shape of the data at 0° and the angular distribution at 10 MeV.     

Polarization transfer in the 2H(d,n)3He reaction at θ = 0°

The vector polarization transfer coefficient K_y^y′ and the tensor analyzing power A_zz have been measured for the ²H($\text{d}$$\text{n}$)³He reaction at θ = 0° over an incident deuteron energy range from 1 to 15 MeV in 0.5 MeV steps. The results agree with the previous ²H($\text{d}$$\text{n}$)³He measurements of Simmons et al. and are nearly identical to the ²H($\text{d}$$\text{n}$)³H measurements of Clegg et al. in the region of overlap. The present results provide an accurate and complete set of the observables necessary to use the ²H($\text{d}$,$\text{n}$)³He reaction as a source of polarized neutrons.     

Spins and parities of low-lying states in 79Kr from the 78Kr(d,p)79Kr reaction

The structure of Kr has been investigated via the ⁷⁸Kr($\text{d}$, p)⁷⁹ Kr reaction using an isotopically enriched gas target and an 11.0 MeV vector-polarized deuteron beam. Differential cross sections, σ, and vector analyzing powers, A_y, have been measured from 25° to 95° for 10 proton groups below 2.5 MeV excitation energy. Comparisons of these distributions to DWBA calculations and empirical shapes were made to extract spectroscopic factors and values of spin and parity for these states.     

Polarization transfer effects in (p, n reactions on light nuclei at θ = 0°

Transverse polarization transfer coefficients K_y^y′ have been measured at a reaction angle of 0° for the reactions ${}^9\text{Be}\text{(}\text{p}\text{,}\text{n}\text{)}{}^9\text{B}\text{,}{}^{11}\text{C}$ and ${}^{13}\text{C}\text{(}\text{p}\text{,}\text{n}\text{)}{}^{13}\text{N}$. In the energy range covered by these measurements, i.e., from about 7 to 15 MeV, the K_y^y′(0) values are generally positive. The polarization transfer excitation functions all show considerable structure which we largely attribute to compound nucleus effects.     

Differential cross sections and analyzing powers for pd elastic scattering below 1.0 MeV

Differential cross sections for the elastic pd scattering were measured at seven energies between 0.4 and 1.0 MeV for scattering angles from θ_c.m. = 44.5° to 149.2°. A mixture of D₂ and Kr was used as target gas and the pd differential cross sections were determined relative to those of pKr scattering with a statistical error of $\text{Δσ}\text{σ}$ ～5 × 10^?3. Analyzing powers for $\text{p}$d scattering were measured at 0.8, 0.9 and 1.0 MeV with a statistical error of ΔA_y ～5 × 10^?4.     

Deuteron d-state effects for the reactions 117Sn(d, p)118Sn and 119Sn(d, p)120Sn

Angular distributions of the differential cross section and the three tensor analyzing powers were measured for the reactions ¹¹⁷Sn($\text{d}$, p)¹¹⁸Sn and ¹¹⁹Sn($\text{d}$, p)¹²⁰Sn at E_d = 12 MeV. In addition, excitation functions of the tensor analyzing power T₂₀ were measured at proton lab angles of 0° and 5° for energies ranging from 10 to 12 MeV. At forward angles, the tensor analyzing powers for the ground state (l_n = 0) transitions are more than an order of magnitude larger than the predictions of distorted-wave calculations which neglect the deuteron D-state. Qualitative agreement with the measurements is obtained when the D-state is included.     

Proton scattering from 9Be between 6 and 30 MeV and the structure of 9Be

Differential cross-section excitation functions at lab scattering angles 86.9°, 120.0°, 140.0° and 160.0° were measured for ⁹Be(p, p_o)⁹Be, ⁹Be(p, p₂)⁹Be and ⁹Be(p, d₀)⁸Be at proton lab energies from 6 to 15 MeV in 100 keV steps. A broad anomaly was observed in the ⁹Be(p, p₀)⁹Be excitation functions. Differential cross-section angular distributions were measured for ⁹Be(p, p₀)⁹Be and ⁹Be(p, p₂)⁹Be at lab energies of 13.0, 14.0, 15.0, 21.35 and 30.3 MeV and for ⁹Be(p, d₀)⁸Be at 13.0, 14.0, 15.0 and 21.35 MeV. Angular distributions of polarization analysing powers for ⁹Be($\text{p}$,p₀)⁹Be, ⁹Be(p, p₂)⁹Be and ⁹Be($\text{p}$, d₀)⁸Be were measured at 8.0, 11.0, 12.0, 13.0 and 15.0 MeV. A spherical optical-model (SOM) analysis of the elastic scattering angular distribution data from 13.0 to 30.3 MeV showed that an energy dependence of only V_R and W_s (volume real and surface imaginary depths) is sufficient to reproduce the measurements. Coupled-channels (CC) analyses were made with a quadrupole-deformed optical-model potential and strong coupling of $\text{3}\text{2}{}^{\mathrm{?}}$, $\text{5}\text{2}{}^{\mathrm{?}}$ and $\text{7}\text{2}{}^{\mathrm{?}}$ levels of a $\text{K =}\text{3}\text{2}$ ground-state rotational band of ⁹Be. The ⁹Be(p, p₀)⁹Be and ⁹Be(p, p₂)⁹Be data from 13.0 to 30.3 MeV were analyzed simultaneously at each energy, varying only V_R and W_s with energy, for a potential deformation of β = 1.1. Both SOM and CC analyses indicated the same energy dependence in V_R, while W_s averaged 3.5 MeV lower in CC than in SOM, with both energy dependences consistent with previous analyses of nucleon scattering from 1p shell nuclei.     

Giant resonances in f-p shell nuclei studied by inelastic scattering of 80 MeV 3He ions

Spectra of ⁴⁸Ti, ⁵⁶Fe, ⁵⁹Co and ⁶⁰Ni have been investigated for excitation energies of 10–20 MeV by inelastic scattering of 80 MeV ³He particles. Broad peaks with excitation energies of about $\text{63±1 A}{}^{\mathrm{<mtext>?</mtext><mtext>1</mtext><mtext>3</mtext>}}\text{MeV}$ and FWHM of 6 MeV have been observed. Much narrower satellite peaks occur at excitation energies about $\text{51±1 A}{}^{\mathrm{<mtext>?</mtext><mtext>1</mtext><mtext>3</mtext>}}\text{MeV}$. The angular distributions of the sum of these peaks were compared to extended optical model DWBA calculations which confirm the predominant L = 2 character of the GR. A tentative assignment of L = 2 or 4 was made for the 13.5 MeV satellite peak in ⁵⁶Fe. We see no definite evidence for the presence of an L = 1 GR component.     

Study of the (p,pn) reaction in light nuclei

The (p, pn) reaction on ²H, ⁶Li, ⁷Li, ⁹Be has been studied at 47 MeV bombarding energy. Excitation energy spectra and energy sharing spectra are presented. Fragmentary information on ¹⁰B, ¹¹B and ¹²C was also obtained. Sequential decay contributions to the ⁶Li(p, pn)⁵Li¹ reaction suggest an admixture of parentage $\text{(α)π(}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)π(}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ for the (3^?), 23 MeV excited state of ⁶Be. A possible 15.5 MeV excited state in ⁶Be is reported. An extensive study of the ⁹Be (p, pn)⁸Be reaction for 45 MeV protons was made. Results for θ_p = θ_n = 25°, 30°, 35°, 40°, 45°, 55°, 65°; θ_n = 40°, θ_p = 25°, 30°, 35°, 40°, 45°, 55°, 65°; θ_p/θ_n = 40°/45°, 38.5° are reported and compared to DWIA calculations. Agreement is good when the lower momentum components of the wave function are sampled, and deteriorates as higher momenta are required. Results are in agreement with the Cohen and Kurath spectroscopic factors for ⁹Be.     

Elastic and inelastic scattering of 6Li and 7Li by 54Fe at E = 36–50 MeV

Detailed angular distributions for the elastic and inelastic scattering of ⁷Li at E = 36, 42, and 48 MeV and of ⁶Li at E = 38, 44, and 50 MeV by ⁵⁴Fe have been measured. It is not possible to describe both sets of data with the same set of optical-model parameters. The ratio of $\text{U}\text{W}$ is 0.8 for ⁷Li and 1.4 for ⁶Li at the strong absorption radius, implying stronger absorption for ⁷Li than for ⁶Li. No energy dependence in the optical-model parameters was necessary for either ⁶Li or ⁷Li. The inelastic scattering from the ⁵⁴Fe 2⁺, 1.41 MeV state was well described by the DWBA and the extracted deformation length (βR = 0.62) was the same for both ⁶Li and ⁷Li scattering. It was not possible to describe the ⁷Li projectile excitation data with collective-model DWBA calculations showing that more detailed calculations for the projectile excitation are necessary.     

Microwave optical double resonance and continuous wave dye laser excitation spectroscopy of NO2: Rotational assignment of the K = 0−4 subbands of the 593 nm band

A rotational assignment of approximately 80 lines with K_a′ = 0, 1, 2, 3, and 4 has been made of the 593 nm ${}^2\text{A}{}_1\text{→}{}^2\text{B}{}_2$ band of NO₂ using cw dye laser excitation and microwave optical double-resonance spectroscopy. Rotational constants for the ²B₂ state were obtained as A = 8.52 cm^?1, B = 0.458 cm^?1, and C = 0.388 cm^?1. Spin splittings for the K_a′ = 0 excited state levels fit a simple symmetric top formula and give $\text{(?}{}_{\mathrm{bb}}\text{+ ?}{}_{\mathrm{cc}}\text{)}\text{2}\text{= ?0.0483}\text{cm}{}^{\mathrm{?1}}$. Spin splittings for K_a′ = 1 (N′ even) are irregular and are shown to change sign between N′ = 6 and 8. Assuming that the large inertial defect of 4.66 amu Ų arises solely from A, a structure for the ²B₂ state is obtained which gives $\text{r}\text{(NO) = 1.35}\text{A}\text{?}$ and an ONO angle of 105°. Alternatively, weighting the three rotational constants equally gives $\text{r = 1.29}\text{A}\text{?}$ and θ = 118°.     

The 12C(13C, α)21Ne reaction: High-spin states,resonances and coherence widths

Excitation functions were measured for states of ²¹Ne populated by the ${}^{12}\text{C}\text{(}{}^{13}\text{C}\text{, α)}$ reaction over the bombarding energy range E_lab = 18.2–32.0 MeV (18.4–27.0 MeV) at θ_lab = 7°(25°) in in 200 keV steps, and average coherence widths of states and the moment of inertia of the compound nucleus ²⁵Mg were obtained from these excitation functions. A statistical analysis of these data was performed. Angular distributions for states in ²¹Ne to 10 MeV in excitation energy were measured at θ_lab = 7°, 18°, 28° and 43° at bombarding energies from 29.0 to 31.0 MeV in 400 keV steps. These data along with Hauser-Feshbach predictions allow us to suggest spins for some states as well as to suggest possible candidates for rotational bands in ²¹Ne.     

On the separation of the direct reaction contribution in fluctuating cross sections by the use of polarized particles

A method to determine the direct reaction contribution y_D to the differential cross section in the presence of Ericson fluctuations is proposed. For the scattering of polarized $\text{spin}\text{-}\text{1}\text{2}$ particles from spinless nuclei the statistical analysis of the differential cross section dσ/dΩ and of the differential analyzing power $\text{(}\text{d}\text{σ/}\text{d}\text{Ω)A}$ allows an unambiguous and model independent extraction of y_D. The method is applied to the elastic scattering of polarized protons from ²⁶Mg, ⁸⁸Sr and ⁹⁰Zr; the results are in agreement with Hauser-Feshbach calculations.     

Crystal field parameters and phase transitions in ErSb

The crystal field levels of the Er ($\text{J =}\text{15}\text{2}$) ion in a single crystal of ErSb have been measured by inelastic neutron scattering. The crystal field parameters obtained by a least squares fit to the spectra at several temperatures are: B₄ = (0·473 ± 0·005) × 10^?2°K and B₆ = (0·59 ± 0·06) × 10^?5°K, which differ considerably from the values o by interpolation from measurements on other compounds. In addition the temperature dependence of the magnetic scattering in the vicinity of the Néel temperature (T_N = 3·55°K) clearly demonstrates that the transition is second order in contrast to the first order behavior suggested by specific heat measurements. Also, any lattice distortion accompanying the magnetic ordering is less than 0.1 per cent, the resolution of the present experiment.     

Relations between measured and calculated spin observables in inelastic scattering of polarized protons for excitation of the 1+, T = 0 state in 12C

We analyze the most important spin observables representing the difference functions (P-A _y ) and (P-A _y )σ, along with the spin-transfer coefficients D _NN , D _SS , and D _LL in the inelastic scattering of polarized protons. We examine the excitation of the state 1⁺, T = 0 (12.71 MeV) in the ¹²C nucleus at the energies of projectile protons E _p = 200 MeV and E _p ～ 400 MeV. These spin observables are treated in the context of the exchange features of the effective interaction.     

Polarization of preequilibrium proton emission in the 93Nb + 14N reaction

Spin polarization of protons emitted at 20° and 40° in the ⁹³Nb + ¹⁴N reaction at 95 MeV has been measured by the double scattering method using a polarimeter particularly designed for protons having a continuous energy distribution.The result shows that the polarization is small for low-energy protons, but increases smoothly with the increase of proton energy, reaching around + 20 % at about 20 MeV in the center-of-mass system. Energy and angular distributions of protons measured in the same reaction indicate coexistence of equilibrium and preequilibrium components in the proton emission of interest, the fraction of the preequilibrium component increasing with the increasing proton energy. If we assume that protons emitted in equilibrium are completely unpolarized, and that the value of polarization (P) for the preequilibrium component is independent of proton energy, the present result is consistent with $\text{P ? + 22 \%}$ for the emission at 20° and $\text{P ? + 38 \%}$ for the emission at 40°.The result is discussed in terms of the hot-spot model for precompound decay.     

Polarization of protons in C12(d,p)C13 reaction

The angular distributions of the polarization of protons from C¹²(d,p)C¹³(g.s) reaction were measured at 200 keV intervals for deuteron energies from 1.40 to 2.40 MeV. Elastic scattering on C¹² at 45 ° (lab) was used to analyze the polarization. Positive sign of the polarization corresponds to the vector productK _d ×K _p . The maximum polarization observed is about 30%. The results are not similar to those obtained from the mirror reaction C¹²(d,n)N¹³ in the same deuteron energy range.