A MEASUREMENT OF THE LONGITUDINAL POLARIZATION OF NEON-19 POSITRONS
Abstract
An experiment whose object is to measure the energy dependence of helicity of positrons emitted from Ne-19 is described. The positron helicity is measured indirectly by transferring it to the annihilation-in-flight photons, whose transmission through a magnetized iron cylinder is dependent on their polarisation. The positron helicity therefore results in a difference of the counting rates for opposed directions of the magnetic field. The measured dependence of this asymmetry with pulseheight is compared with a computation which assumes the validity of the two component neutrino theory of beta decay and neglects the depolarisation of positrons. A good fit of theoretical curve to the experimental points is obtained for pulseheights larger than about 1.3 Mev. A strong disagreement is found in the pulseheight range between 0.75 and 1.0 Mev, where the experimental asymmetries are much lower than the prediction. The measurement of the asymmetry of bremsstrahlung produced in copper by electrons from a Sr-Y-90 source is used in order to measure the effective number of aligned electrons in the magnetised iron cylinder. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1961
- Accession Number
- AD0261907
Entities
People
- Jovan Jovanovic
Organizations
- Washington University in St. Louis