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Title:A coincident measurement of the three-body photodisintegration of helium-3
Author(s):Kolb, Norman Reed
Doctoral Committee Chair(s):Smith, J.H.
Department / Program:Physics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Physics, Nuclear
Abstract:This experiment measured coincident neutron-proton pairs from the photodisintegration of $\sp3$He. The bremsstrahlung photon beam was produced by a 100 MeV electron beam, supplied by the University of Illinois Nuclear Physics Laboratory 100% duty factor electron microtron. The energy and angle of the np pairs were used to reconstruct the energy of the photon, making this a kinematically complete experiment. The $\sp3$He($\gamma$,np)p data were normalized to measured $\sp2$H($\gamma$,np) yields and published deuterium photodisintegration cross sections.
The target was a cryogenic system which maintained the $\sp3$He gas at liquid $\sp4$He temperature. Protons were detected with a dE-E scintillation telescope and neutrons with a position sensitive scintillation array. The proton energy was determined from the energy deposited in a NaI crystal and the neutron energy from the time of flight over a 4 m path. The neutron and proton were detected on opposite sides of the photon beam at opening angles from 122-202 degrees in the lab frame.
Quasi-deuteron breakup events were detected for photon energies of 45-95 MeV. Strong final state interactions prohibited an accurate determination of the quasi-deuteron contribution to the cross section. The single differential cross section $(d\sigma/d\Omega\sb{p})$ for $\sp3$He at $\theta\sb{p}$ = 81$\sp\circ$ was determined by integrating the neutron angular distribution. This cross section, relative to deuterium, ranged from 2.39 $\pm$.16 at 55 MeV to 1.67 $\pm$.27 at 95 MeV.
Issue Date:1990
Rights Information:Copyright 1990 Kolb, Norman Reed
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9021710
OCLC Identifier:(UMI)AAI9021710

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