Nuclear Resonance Fluorescence Studies of Sodium, Aluminum, and Phosphorous.

The nuclear resonant scattering of photons by ('23)Na, ('27)Al, and ('31)P was measured for excitation energies between 4 and 10 MeV, using bremsstrahlung beams with endpoint energies of 7.6 and 10.3 MeV. The energies and intensities of the scattered radiation were measured with a Ge(Li) detector. Elastic scattering and self-absorption measurements determined values of g (,0)('2)/ and g(,0), respectively, for many levels in each of these nuclei. Values of excitation energies were also obtained from these measurements. For several levels, the inelastic scattering of photons was measured to determine branching ratios. The results are compared with earlier spectroscopic studies. For several levels in each nucleus, the measured electromagnetic decay properties are discussed in terms of the particle-rotor model of collective nuclear excitations. The measured properties of two T = 3/2 levels in ('23)Na and ('31)P are also discussed. In addition, some of the self-absorption results are shown to be useful for the purposes of photon flux calibration. Additional photon scattering measurements were carried out for ('11)B, ('88)Sr, ('90)Zr, and ('92)Mo. Self -absorption measurements were carried out for ('11)B and ('24)Mg. The results of these measurements are presented. The ('11)B and ('24)Mg self-absorption results were used for photon flux calibration measurements.