L. D. Knutson

Determination of the asymptotic D- to S-state ratio of the deuteron from sub-Coulomb ( d , p) measurements

Abstract Measurements of the tensor analyzing powers for sub-Coulomb ( d , p) reactions on 208 Pb have been reanalyzed to obtain a new value of η , the deuteron asymptotic D- to S-state wave function ratio. The new analysis includes corrections for finite-range effects, deuteron-nucleus tensor forces and deuteron stretching. Our result, η = 0.0271 ± 0.0008, is (3–4)% larger than the values derived from conventional nucleon-nucleon potentials.

Effects of the deuteron D state in sub-Coulomb (d, p) reactions

Angular distributions of the cross section, the vector analyzing power, and the three tensor analyzing powers have been measured for (d, p) reactions on /sup 90/Zr at 5.5 MeV and /sup 208/Pb at 9.0 MeV. The measurements are compared with calculations based on the distorted-wave Born approximation. For /sup 208/Pb the calculations are in excellent agreement with the measurements, while for /sup 90/Zr the agreement is only qualitative. The effect of the deuteron D state on the measured quantities is investigated. It is shown that the tensor analyzing powers arise almost entirely from the D state. A semiclassical model for sub-Coulomb (d, p) reactions is presented. This model successfully reproduces the qualitative features of the observed analyzing powers, and makes it possible to understand why the D state has a large effect on the tensor analyzing powers.

A deuteron tensor polarimeter using the 3He(d,p)4He reaction☆

Abstract A polarimeter for measuring the moments t20, Re (t21), and Re (t22) of a tensor polarized deuteron beam is described. This polarimeter makes use of the 3He(d,p)4He reaction near the 3 2 + resonance at Ed = 430 keV. It has been used in polarized-beam experiments for incident deuteron energies up to 13 MeV.

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

Abstract Angular distributions of the differential cross section and the three tensor analyzing powers were measured for the reactions 117 Sn( d , p) 118 Sn and 119 Sn( d , p) 120 Sn at E d = 12 MeV. In addition, excitation functions of the tensor analyzing power T 20 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.

High precision measurement of the analyzing powers for d-p elastic scattering at Ed = 10 MeV

Abstract Measurements of the analyzing powers iT11, T20, T21 and T22 are presented for d -p elastic scattering at Ed = 10 MeV. The uncertainties in the measured analyzing powers are typically ± 0.0003. The results are compared with the predictions of Faddeev calculations which employ a separable representation of the Paris nucleon-nucleon potential.

D-state effects in low-energy (d,t) and (d,3He) reactions

Abstract Measurements of the tensor analyzing powers are presented for ( d , t ) reactions on 91Zr,119Sn and 208Pb and for the ( d , 3 He ) reaction on 63Cu. The measurements are sensitive to D-state components in the three-nucleon bound-state wave function and allow one to determine the value of the parameter D2. The D2 values are compared with recent theoretical predictions.

On the determination of the deuteron asymptotic D- to S-state wave function ratio by the pole-extrapolation method: Truncation errors☆

Abstract The pole-extrapolation method for determining the asymptotic D-state to S-state wave function ratio of the deuteron is discussed. It is concluded that the method is subject to systematic errors of 10–20% or more, which result from truncation of the polynomial series used to extrapolate the d-p elastic scattering measurements. We see no clear-cut evidence that the polynomial series is converging.

A study of deuteron quadrupole moment effects in sub-coulomb scattering of tensor polarized deuterons☆

Abstract Measurements of the tensor analyzing power T 20 are presented for deuteron elastic scattering from 208 Pb at energies below the Coulomb barrier. It is found that, for energies below about 7 MeV, T 20 arises primarily from the interaction of the deuteron quadrupole moment with the nuclear electric field gradient. Contributions to T 20 from nuclear interactions with the target are shown to be very small for E d ≲ 5 MeV. Measurements of T 20 at E d = 4 MeV, accurate to ± 8 × 10 −5 , are presented. After correcting for deuteron stretching and a number of additional small effects, the data are used to make a new determination of the quadrupole moment. The result, Q = 0.282 ± 0.019 fm 2 , is in good agreement with the conventional value deduced from molecular hyperfine structure data.

An absolute standard for deuteron vector analyzing powers

Abstract Deuteron induced reactions with the spin-parity structure 1 + +0 + →0 + +0 − have properties which allow an absolute determination of iT 11 . It is shown that, under certain conditions, one can accurately determine the vector analyzing power for such reactions by making relatively inaccurate measurements of the tensor analyzing powers. The vector analyzing power of the reaction 16 O ( d , α 3 ) 14 N is determined with an accuracy of better than 1% at E d =6.84 MeV and θ lab =29°. To provide a convenient secondary standard, the vector analyzing power of 3 He( d , p) 4 He at E d =6.44 MeV is determined to better than 1% by direct comparison with the 16 O ( d , α 3 ) 14 N reaction.

Parity conservation and polarization phenomena for break-up reactions

Abstract The conservation of parity is known to place restrictions on the polarization observables for nuclear reactions. For reactions which lead to a final state which contains two particles, the number of non-zero polarization observables is reduced by about a factor of two. The purpose of the present paper is to establish restrictions on the various polarization observables resulting from parity conservation for reactions in which the final state contains three particles. It is shown that for certain special cases the restrictions have a form similar to that for reactions in which the final state contains two particles.