F. D. Correll

The description of polarization analyzing powers for three-body breakup reactions☆

Abstract We present a discussion of the geometrical aspects of the measurement of analyzing powers for nuclear reactions with three particles in the final state that are induced by polarized spin-1 or spin- 1 2 particles. The present interest is focussed on the reac D( p , pp)n and H( d , pp)n, for which a measurement program at 16 MeV deuteron energy is currently underway at the Los Alamos Scientific Laboratory (LASL).

The interactions of polarised tritons with 32S

Abstract Cross sections and analysing powers have been measured for the elastic and inelastic scattering of tritons from 32 S, along with the 32 S ( t , α) 31 P reaction data, using the 17 MeV polarised triton beam available at the Los Alamos National Laboratory. An optical model analysis of the elastic scattering data has yielded a triton spin-orbit potential with an unconventional geometry. The inelastic analysing powers have shown a requirement for including the deformation of the spin-orbit potential in the coupling potential form factor. The ( t , α ) reaction data have been analysed using the zero-range DWBA. Certain features of this reaction data which could not be described by the DWBA are well predicted when the analysis is extended to include explicitly the inelastic couplings and two-step processes through a CCBA calculation.

Study of the reaction H(d, 2p)n at 16 MeV around collinear configurations

Abstract The cross section and the analyzing powers Ay, Axx, Axz and Ayy for the reaction H ( d , 2 p ) n are studied by kinematically overdetermined measurements at an incident energy of 16 MeV at collinear and somewhat off-collinear kinematic conditions. A three-body Faddeev model using two realistic separable potentials that have different short-range parts gives a good fit to the data. Uncertainties in Coulomb corrections make it difficult to draw definitive conclusions about possible three-nucleon force effects at collinearity conditions.

d + α Scattering from 12 to 17 MeV☆

Abstract A previous phase-shift analysis of the d + α system had indicated that the solution obtained might not describe the backward-angle tensor analyzing powers very well above about 10 MeV. We have measured differential cross sections and all four analyzing powers A y , A xx , A yy and A xz at deuteron bombarding energies of 12, 14, 15 and 17 MeV, with some emphasis on the backward-angle region. The discrepancy with the previous phase-shift analysis was confirmed, and we have studied the changes in the phase parameters necessary to improve the fit to our new measurements.

Low-Energy Charged-Particle Fusion Reactions

We have initiated a program at Los Alamos to measure cross sections for the charged-particle reactions D(t,n)4He, T(t,2n)4He, D(d,n)3He, and D(d,p)T that are fundamental to the understanding of controlled thermonuclear fusion. Interest in these processes is primarily in the region below 100-keV bombarding energy, and accordingly the design range for the measurements is 10-120 keV. Our desired accuracy is 5% or less, compared with present systematic uncertainties of up to 50%. The experiment features a negative ion source and highly stable injector for the low-energy beam, measurement of beam intensity with a precision calorimeter, a windowless cryogenic target, calibration of the target density with a high-energy Van-de-Graaff beam, and a time-of-flight laser spectrometer to determine the absolute energy. Preliminary data have been obtained on the d + d reactions while preparations are underway for introducing tritium into the system.

Analyzing-power formalism for three-body final states

Various relations important for extraction of analyzing powers from data on reactions involving three particles in the final state were derived. Several of the results pertinent for spin-1/2 and spin-1 polarized beams are presented here. These may be used in analysis of the /sup 1/H(d-vector,pp)n reaction. 3 figures. (RWR)

Tensor analyzing powers in the 1H(d↘,pp)n reaction at 16 MeV I. The symmetric, constant‐relative‐energy configurations

Experimental results for the tensor analyzing powers A/sub xx/ and A/sub yz/ in the /sup 1/H(d-vector, pp)n reaction at 16 MeV for a series of symmetric, constant-relative-energy configurations are reported and compared with the results of recent Faddeev calculations using a separable NN potential. In general, the agreement seems fairly good, although there is some evidence that the measured values of A/sub yz/ tend to be slightly smaller than the prediction, whereas for A/sub xx/ the opposite appears to be true. 1 figure, 1 table. (RWR)