Acquired Polarization in Fundamental Symmetry Experiments
Abstract
One interesting class of fundamental symmetry violation tests involves the measurement of low energy neutron transmission through a thick target as projectile/target spin orientations are changed. As the neutron beam propagates through a target, certain components are preferentially absorbed by nuclear resonances. This induces regenerative effects in thick targets, known as the acquired polarization effect, which complicate the interpretation of transmission measurements. We focus on the role that nuclear resonance spectroscopy plays in beam modification. We determine three basic results. First, with known resonance parameters for spin 1/2 targets 57Fe, 102Rh, 111Cd, 113Cd, 117Sn, and 203 Tl, and spin 7/2 target 139La, the relative sizes of the various terms are determined, including the values of the cross sections, transmission percentages, the size of the transmission effect, and the percentage of the transmission effect caused by acquired polarization. Second, the effect of imperfect target polarization reversal on the value of the transmission effect is determined in the case of 113Cd. It is found that target orientation inefficiencies as small as 3% will mimic a parity violation. Third, the effect of the depolarization term on the relative size of the acquired polarization is explored.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 13, 1991
- Accession Number
- ADA245646
Entities
People
- Paul A. Larson
Organizations
- United States Naval Academy