a Coincident Measurement of the Three-Body Photodisintegration of HELIUM-3.
Abstract
This experiment measured coincident neutron-proton pairs from the photodisintegration of ^3 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 ^3He(gamma,np)p data were normalized to measured ^2H( gamma,np) yields and published deuterium photodisintegration cross sections. The target was a cryogenic system which maintained the ^3He gas at liquid ^4He 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 (dsigma/dOmega_ {p}) for ^3He at theta_{p} = 81 ^circ was determined by integrating the neutron angular distribution. This cross section, relative to deuterium, ranged from 2.39 +/- .16 at 55 MeV to 1.67 +/-.27 at 95 MeV.
- Publication:
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Ph.D. Thesis
- Pub Date:
- January 1990
- Bibcode:
- 1990PhDT........99K
- Keywords:
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- Physics: Nuclear