Gerald G. Ohlsen

Techniques for measurement of spin-12 and spin-1 polarization analyzing tensors☆

Abstract Techniques for measurement of spin - 1 2 and spin-1 analyzing tensors with a view to the control or elimination of first-order systematic errors which may arise from misalignments of various types are discussed. The concept of a “proper flip” and a “nonproper flip” is introduced for both spin 1 2 and spin 1. Several methods for measurement of spin-1 analyzing tensors are described and their relative merits are evaluated.

Depolarization and emittance degradation effects associated with charge transfer in a magnetic field

Abstract The effects on beam emittance and polarization which result from charge-transfer collisions within a magnetic field region are quantitatively discussed. The minimum magnetic field strength required to prevent depolarization under various circumstances is given. It is concluded that the Lamb-shift type of polarized-ion source has significant advantages over conventional polarized-ion sources if negative ions are required.

Source of polarized negative hydrogen and deuterium ions

Abstract A high-performance source of polarized negative hydrogen and deuterium ions is described. The source uses charge exchange in cesium to produce an intense metastable beam, ‘spin filtering’ of the metastable atoms to select a particular nuclear substate, and charge exchange in argon to selectively convert the polarized metastable atoms to negative ions. A D − current of 600 nA with P 3 = 0.78 and an H − current of 300 nA with P = 0.90 have been obtained.

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).

Techniques for polarization transfer coefficient determination

Abstract It is shown how polarization transfer coefficients in reactions with the spin structures 1 2 + A → 1 + B , 1 + A → 1 + B and 1 + A → 1 2 + B can be determined by ratio techniques in which detector efficiencies, solid angles, and relative counting interval are cancelled out. The relative merits of using a “polarized-to-unpolarized” ratio method to “spin-up-to-spin-down” ratio method are discussed.

Polarization and polarization transfer in the 2H(d, n)3He reaction at 10 MeV

Abstract Angular distributions of six polarization transfer coefficients K x x′ (θ), k x z′ (θ), K z x (θ), K z z (θ), and K yy y (θ) ; of the four analyzing powers Ay(θ), Axx(θ), Ayy(θ), and Azz(θ); and of the polarization function Pý(θ), have been measured atEd = 10.00 MeV for the reaction 2H(d, n)3He. Measurements were made for neutron lab angles between 0° and 80° in 10° steps. Additionally the y-axis associated quantities were measured at θ1ab = 99°. Most of the measured coefficients are large at some angles and all show considerable variation with angle.

Absolute deuteron-polarization measurement

Abstract Data obtained from d- 4 He double scattering at 11.5 MeV (both scatterings), and over a range of second scattering angles which includes the first scattering angle, are presented. It is shown how this data may be used to provide an absolute calibration for the polarization of a beam of deuterons produced by a polarized-ion source.

A surface-delta description of analyzing power measurements for collective states of Ni and Zn isotopes☆

Abstract Analyzing powers and differential cross sections for the inelastic scattering of 15 MeV polarized protons to the stronger collective states of 58, 60 Ni and 64 Zn have been measured. The data were compared to detailed microscopic reaction calculations using a central plus spin-dependent effective interaction. The nuclear structure wave functions used were obtained from a quasiparticle random-phase appoximation calculation using a spin-dependent surface delta interaction and a basis set containing both neutron and proton configurations. The overall quality of the fits strongly suggests that the surface-delta wave functions provide a good representation for spherical nuclei in this intermediate mass range. The effects of exchange and further modifications to the microscopic effective interaction are discussed.

Study of the D(d, d)D, D (d, p)T and D(d, n)3He reactions with polarized deuterons

Abstract The vector analysing power of the D(d, d)D, D(d, p)T and D(d, n) 3 He reactions have been measured at 10 MeV deuteron bombarding energy. The analysig power for elastic scattering is consistent with zero at all angles. The D(d, p)T and D(d, n) 3 He analysing power is consistent, within the errors, with charge symmetry.

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.