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

RUI：偏振光束和目标的光核物理研究

• 批准号: 1301843
• 负责人: C. Steven Whisnant
• 金额: $ 4万
• 依托单位: James Madison University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1301843&HistoricalAwards=false
• 关键词: RUI; Study; Photonuclear; Physics; Polarized

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.

该奖项支持利用偏振光束和目标进行光核反应的研究，以研究康普顿散射下核子和核子共振的性质，并通过光裂变研究重核。此外，我们在杰弗逊实验室（JLab）使用的HD靶材的生产中发挥了关键作用。杜克大学的HIGS（高强度伽马源）设施是极化和非极化核子和核目标康普顿散射的理想选择。2013年秋季将开始对质子和中子进行全面的康普顿散射，以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利用了光束不对称性在直接中子产生过程中随光束能量和靶能量的强烈变化。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。设备升级后，冷冻自旋高清靶（HDIce）将用于JLab的三个“A”级实验。所有这些目标中使用的高纯度气体将在JMU进行净化。98% HD的商业气体在低温下蒸馏，分离剩余的H2和D2，产生用于制造具有很长自旋松弛时间的目标的气体。最近对酿酒厂的升级使H2和D2杂质的气体产量比以前低得多，从而为下一轮实验提供了更高的质量目标。现有的天然气储存库足以生产所需的天然气。本科学生将参与这项研究的各个方面，并将获得核实验和探测器，数据分析和核物理应用方面的经验。