Polarization Transfer Coefficients at E(d) = 6 Mev for the Charge Symmetric Triton (polarized Deuteron, Polarized Neutron) HELIUM-4 and HELIUM-3 (polarized Deuteron, Polarized Proton) HELIUM-4 Reactions.
Polarization transfer coefficients K(,z)('x')((THETA)), K(,y)('y')((THETA)), and K(,zz)('y')((THETA)) are. measured at angles forward of (THETA)(,LAB) = 60(DEGREES) for the charge symmetric. ('3)H(d,n)('4)He and ('3)He(d,p)('4)He reactions at E(,d) = 6 MeV. These(' ). measurements were motivated in part to explore further the extent of differences in the tensor analyzing power A(,zz)(0(DEGREES)) observed earlier for these reactions. In addition, polarization transfer coefficients, which involve different and somewhat more selective combinations of matrix elements than do the usual polarization observables, are expected to provide new information in an energy region where complex level structures have been predicted. While differences between corresponding observables in both reactions were found, it is not yet certain as to whether such difference may be attributable solely to the coulomb effects. The polarization transfer coefficients were measured using the. OSU polarized ion source which provides a vector (p(,z) = 0.52) or(, ). tensor (p(,zz) = 0.78) polarized deuteron beam. For the ('3)He(d,p)('4)He(' )(, ). measurements, ('3)He was contained at 7 atm. in a small diameter gas. cell. The polarization of the reaction protons was determined by p-(alpha). scattering at (TURN) 10 MeV into symmetrically positioned, ((THETA)(,2) = (+OR-)60(DEGREES)),. surface barrier side detectors. The detectors were located within. the ('4)He gas (38 atm.) contained inside a stainless steel vessel by a. thin (25 (mu)m) Ta entrance window through which the reaction protons. entered. Background counts were reduced by allowing the reaction. protons to pass through a "thin" (500 (mu)m) transmission surface. barrier detector before entering the vaned region of the polarimeter,. and using those signals to gate the side particle detectors. For the(, ). ('3)H(d,n)('4)He measurements, neutrons were produced in a 7 mg/cm('2) thick Ti-T target on a 0.5 mm Pt backing. The polarization of the 20 MeV reaction neutrons was determined by n-(alpha) scattering from a high pressure, (250 atm.) ('4)He gas scintillator into symmetrically positioned, ((THETA)(,2) = (+OR-)112(DEGREES)), NE102 plastic scintillator neutron detectors. A fast coincidence between the ('4)He recoils and the scattered neutrons allowed a gated recoil alpha spectra corresponding to each neutron detector event at angle (+OR-)(THETA)(,2) to be collected. Comparison of the experimental results to existing data is. difficult since the only existing angular distributions of polarization. transfer coefficients in this energy region are at E(,d) = 7 MeV for the(, ). ('3)H(d,n)('4)He reaction, and at E(,d) = 8 MeV for the ('3)He(d,p)('4)He reaction. The data which do exist, however, show similarity in angular dependence to the present measurements. A comparison of the present experimental results between the two reactions shows that differences do exist, especially at (THETA) = 0(DEGREES) and also at (THETA)(,LAB) =45(DEGREES). While it may be possible to account for these differences through a charge independent R-matrix analysis, (currently underway by Dodder and Hale at Los Alamos), preliminary calculations have suffered for the lack of these types of data.
- Pub Date:
- Physics: Nuclear