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Koester, L.J. O'Fallon, John Robert 2011-05-20T14:40:59Z 2011-05-20T14:40:59Z 10000-01-01 1965 "The differential cross section for the, reaction He3(y,n+)H3 was measured for photon energies of 180 to/260 MeV (momentum transfer 1.2 F-1 to 1.9 F-1). A target of gaseous He at 20.4 K and approximately one atmosphere preesure was irradiated by a 270 MeV bremsstrahlung x-ray beam. The reaction was obserVed by detecting , ' ' + 3 "" . ,n .. H coinciq.ences. The counter telescopes consisted ()f seven plastic scintillators for the pions and four tl'ansmiss10ntype semiconduc1;or detectors for the tritons. Pulses froln the 'semiconductor detectors and the scintillators were displayed on a dual beam oscilloscope -.nd photographed. E and dE/dx relations were used for 'particle identification. Tritons with enere;ies between 9.7 and 24.5 MeV were observed at laboratory angles of 260,300, 350, and 400• '0 At 26 the cross sections in the center of mass system ranged from 2.55 !. 0.34 ~b/ster to 0.78 ±. 0.16~b/ster, decreasing with increasing photon ,energy. An impulse approximation calculation was performed to relate the cross section to the matter form factor of the 3-nucleon system under the assumption of 'identical wave functions for He3 and H3, Values for the matter form factor 'obtained using this relation and the cross sections of this experiment were found to lie below the values obtained from the results of electron scattering experiments. Several plausible arguments may be presented to explain this discrepancy. Under the condition of proximity of two nucleons, which depends on the internal momentum distribution, phase space considerations (Wilson model) lavor two nucleon ejection over free pion production. Pions may be scattered or absorbed before they escape the nucleus. Alterpatively, the pion production amplitude may have a many-body aspect; that is, 'it _y depend on the coordinates of more than one nucleon." Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-20T14:40:59Z No. of bitstreams: 1 1965_ofallon.pdf: 3324602 bytes, checksum: d0dd199c687f2b6b7ce5c09cf5a37fcb (MD5) Made available in DSpace on 2011-05-20T14:40:59Z (GMT). No. of bitstreams: 1 1965_ofallon.pdf: 3324602 bytes, checksum: d0dd199c687f2b6b7ce5c09cf5a37fcb (MD5) Previous issue date: 1965 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-20T14:41:00Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:12:37-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Thesis U of I Only 6191828 http://hdl.handle.net/2142/23977 en 1965 John Robert O'Fallon pion scattering pion decay protons dueteron gaseous He Experimental study of the reaction He3 ([v], [pi+])H3 up to 260 MeV Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.