M. N. Thompson

Measurements of 10B(γ, p) and 10B(γ, pn) Cross Sections at Eγ=66∼103 MeV

Measurements of the cross sections of 10 B(γ, p) and 10 B(γ, pn) with tagged photons have been performed at E γ =66∼103 MeV. The results of both the 10 B(γ, p) and (γ, pn) measurement show the dominance of a two-nucleon photoabsorption process in this energy region.

The Analyzing Power of the 12C(γ, p) Reaction Measured Using Tagged Polarized Photons

The cross sections for 12 C(γ, p ) were measured with tagged polarized photons in the energy range from 41.2 to 93.0 MeV. The photon energy and angular dependence of the analyzing power have been extracted. The results are in better agreement with predictions of the one-nucleon knockout model and RPA theory, than that of the quasi-deuteron model, particularly at higher photon energies.

Precise measurement of the half-life of the Fermi {beta} decay of {sup 26}Al{sup m}

State-of-the-art signal digitization and analysis techniques have been used to measure the half-life of the Fermi {beta} decay of {sup 26}Al{sup m}. The half-life was determined to be 6347.8 {+-} 2.5 ms. This new datum contributes to the experimental testing of the conserved-vector-current hypothesis and the required unitarity of the Cabibbo-Kobayashi-Maskawa matrix: two essential components of the standard model. Detailed discussion of the experimental techniques and data analysis and a thorough investigation of the statistical and systematic uncertainties are presented.

Excitations in the halo nucleus 6 He following the 7 Li(gamma,p) 6 He reaction

A broad excited state was observed in 6-He with energy E_x = 5 +/- 1 MeV and width Gamma = 3 +/- 1 MeV, following the reaction Li-7(gamma,p)He-6. The state is consistent with a number of broad resonances predicted by recent cluster model calculations. The well-established reaction mechanism, combined with a simple and transparent analysis procedure confers considerable validity to this observation.

Excitations in the halo nucleus6Hefollowing the7Li(γ,p)6Hereaction

A broad excited state was observed in 6-He with energy E_x = 5 +/- 1 MeV and width Gamma = 3 +/- 1 MeV, following the reaction Li-7(gamma,p)He-6. The state is consistent with a number of broad resonances predicted by recent cluster model calculations. The well-established reaction mechanism, combined with a simple and transparent analysis procedure confers considerable validity to this observation.

{sup 13}C({ital e},{ital p}{sub 0,1}){sup 12}B differential cross section

The differential cross sections for the reactions {sup 13}C ({gamma},{ital p}{sub 0}) and {sup 13}C ({gamma},{ital p}{sub 1}) have been measured in the energy range 21--26 MeV. Analysis of the present data and the {sup 13}C ({gamma},{ital p}) cross section reveals decay of the giant dipole resonance at 23 MeV, via the {ital p}{sub 4} channel. The valence neutron does not appear to interact strongly with the {sup 12}C core. Isospin splitting effects are observed.

Isospin effects on the /sup 15/N(. gamma. ,2n) reaction cross section

The cross section for the /sup 15/N(..gamma..,2n) reaction has been studied from 20 to 28 MeV. The cross section remains near zero for 3 MeV above threshold, then rises sharply at about 24 MeV, to a maximum value of 1.7 mb. The shape is explained in terms of the density of T/sub >/ states in /sup 14/N at the relevant excitation energy.