RUI: The Study of Photonuclear Physics with Polarized Beams and Targets

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This award supports research on photonuclear reactions with polarized beams and targets to investigate the properties of the nucleon and nucleon resonances with Compton scattering and to study heavy nuclei through photofission. In addition, we play a key role in the production of the HD targets used at Jefferson Lab (JLab).The HIGS (High Intensity Gamma Source) facility at Duke University is ideal for Compton scattering from both polarized and unpolarized nucleon and nuclear targets. A comprehensive program of Compton scattering is beginning in the fall of 2013 on the proton and neutron, which will extract the electromagnetic polarizabilities with high accuracy. The ongoing program of photofission studies with polarized photons exploits the strong variation of the beam asymmetry in direct neutron production both with beam energy and with target. The proposed measurements provide a database for developing nuclear forensics and expand our understanding of this fundamental nuclear reaction.The frozen spin HD target (HDIce) will be used in three "A" rated experiments at JLab after the facility upgrade. The high purity gas used in all these targets will be purified at JMU. Commercial gas that is 98% HD is distilled at low temperature to separate the remaining H2 and D2 and produce gas for making targets with very long spin relaxation times. Recent upgrades to the distillery permit the production of gas with H2 and D2 impurities much lower than previously obtained leading to higher quality targets for the next round of experiments. Existing gas stores are sufficient to produce the required gas.Undergraduate students will be involved in all aspects of this research and will gain experience in nuclear experiments and detectors, data analysis, and applications of nuclear physics.