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Yavin, A.I. Grike, Leo Joseph 2011-07-07T15:13:10Z 2011-07-07T15:13:10Z 10000-01-01 1967 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. Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-07T15:13:10Z No. of bitstreams: 1 1967_grike.pdf: 7390503 bytes, checksum: 2209c5eb97d42bfeb2bc76c8cfbbe201 (MD5) Made available in DSpace on 2011-07-07T15:13:10Z (GMT). No. of bitstreams: 1 1967_grike.pdf: 7390503 bytes, checksum: 2209c5eb97d42bfeb2bc76c8cfbbe201 (MD5) Previous issue date: 1967 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-07T15:13:10Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:32:40-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Thesis U of I Only 6094671 http://hdl.handle.net/2142/25686 en 1967 Leo Joseph Grike, Jr. polonium alpha activities complex nucleus bremsstrahlung energies CGLN cross sections free neutrons surface production models volume production models Study of the Bi209 (gamma,pi-xn) Po209-x and Pb206 (He3,xn) Po209-x reactions by detection of polonium alpha activities Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.