A Coincident Measurement of the Three-body Photodisintegration of Helium-3 PDF Download

Author: Norman Reed Kolb
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ISBN:
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Languages : en
Pages : 412

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Book Description
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 $(dsigma/dOmegasb{p})$ for $sp3$He at $thetasb{p}$ = 81$spcirc$ 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.