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Title:Polarization in the elastic scattering of protons from carbon and nitrogen
Author(s):Steben, John David
Doctoral Committee Chair(s):Brussel, M.K.
Department / Program:Physics
Subject(s):elastic polarized photon scattering
double scattering techniques
proton energy
polarization angular distributions
Abstract:The polarization of protons elastically scattered from nitrogen and carbon has been measured using double scattering techniques 0 The polarization was determined for nitrogen at a scattering angle of 48°c .mo in the proton energy interval 7.6 to 11.8 MeV. The polarization from carbon '~as determined -for protons in the energy interval 12. 6 to 1,30 6 MeV. Polarization angular distributions as well as excitation functions were obtained in this energy interval. For much of the data the energy dependence of the 'polarization was measured with a resolution of 2%. This constitutes a considerable refinement over previous experiments above 10 MeV. : ,/ The polarization resulting from elastic proton scattering " \ '\ with nitrogen targets had a constant value of -0.58+0.10 in f the incident proton energy interval 8.2 to 11.7 MeV. The polarization from carbon, however, varied markedly with energy at most scattering angles. (Example: P(501ab, 12 0 9 MeV) := -008 0 P{500 q 13.2) = -0.4, and P(50°, 13.5) := -0.7.) Throughout the angular range 20° to 140°, polarization measurements from 'carbon covered the .range of energies,from 1288 to 13.4 MeV. ,In addition, ilngular distribution data P (e) were 'obtained separately for the proton .energy ranges 12.8 to 13.1 MeV and 13.1 to 13.4 MeV. r The separate p(e) curves differ significantly for' e > 90°. The energy averaged (12.8 to 13.4 MeV) angular distribution for the polarization of 13.1 MeV protons scattered from carbon ~as compared with optical model calculations. The experimental method involved double scattering, with the second scattering taking place in a 450 polarimeter. Both carbon and nitrogen targets were used as the second scatterer. The proton energies involved in both scatterings were care- fully monitored with Au-Si surface barrier detectors. The polarization analyzing properties of the polarimeter were measured for the carbon (nitrogen) analyzing targets, by first scattering 8.6 (13. 5) MeV protons from carbon at 70iab(50iab) to obtain a highly polarized beam., The nitrogen data were taken in this manner. The p(e,E) ,data described for Cl2 (P/P) near 13 MeV were then obtained using the carbon first target as the polqrization to be measured. The present polarimeter, when used .with a nitrogen target l and solid state detectors, has an overall resolution of 3% and a-'constant polariztion (analyzing>power) 0;: 0. 6±.0.1 for protons of 9to 12.5 MeV. It, would be extremely useful for polarization experiments involving several nuclear-reaction with 'prdtbn 'groups close in energy ,such a's are obtained ill; inelastic scattering from isotopes of A ~ 50.
Issue Date:1965
Genre:Dissertation / Thesis
Rights Information:1965 John David Steben
Date Available in IDEALS:2011-05-20
Identifier in Online Catalog:6187535

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