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

该奖项支持利用偏振光束和目标进行光核反应的研究，用康普顿散射研究核子和核子共振的性质，以及通过光裂变研究重原子核。此外，我们在杰斐逊实验室(JLab)使用的HD靶的生产中扮演着关键角色。杜克大学的HIGS(高强度伽马源)设施是测量极化和未极化核子和核靶的康普顿散射的理想设备。一个关于质子和中子的康普顿散射的综合计划将于2013年秋季开始，它将高精度地提取电磁极化率。正在进行的偏振光子光裂变研究计划利用了直接产生中子时光束不对称性的强烈变化，无论是随着光束能量的变化，还是与目标的变化。拟议的测量为发展核取证提供了一个数据库，并扩大了我们对这一基本核反应的理解。冷冻自旋HD靶(HDIce)将在设施升级后在JLab的三个“A”级实验中使用。所有这些靶子中使用的高纯度气体将在JMU进行净化。含有98%HD的商业气体在低温下蒸馏，以分离剩余的H2和D2，并产生用于制造具有非常长自旋弛豫时间的靶的气体。最近对酿酒厂的升级允许生产H2和D2杂质比以前低得多的天然气，从而为下一轮实验带来更高的质量目标。现有的储气库足以生产所需的气体。本科生将参与这项研究的所有方面，并将在核实验和探测器、数据分析和核物理应用方面获得经验。

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.