Study of the Bi209 (gamma,pi-xn) Po209-x and Pb206 (He3,xn) Po209-x reactions by detection of polonium alpha activities

The cross sections for Bi 209{gamma, pi-xn ) Po209-x were measured for x = 0-3, 5, and 7 and used to estimate the total (gamma, pi-) cross section. Total (gamma, pi-) cross sections have not previously been measured for a complex nucleus. At bremsstrahlung energies of 200,220, and 250 MeV, the total cross sections are 0.79 2.89 and 8.9 mb, respectively. These are 6.5, 24 and 65 times the CGLN cross sections for (gamma, pi-) on free neutrons. This result disagrees with both surface production and volume production models. At all energies, the cross section for x=2 dominates. This cannot be simply explained in terms of the free neutron cross sections. It is suggested that this experiment may be preferentially exciting isobaric analogs in Po209 of the lower excited states in Bi209.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Grike, Leo Joseph

Contributors dc:contributor

• Yavin, A.I.

• polonium alpha activities
• complex nucleus
• bremsstrahlung energies
• CGLN cross sections
• free neutrons
• surface production models
• volume production models

Statement dc:rights

• 1967 Leo Joseph Grike, Jr.

Language dc:language

en

Identifier

6094671

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25686