Pair polarimeter for high-energy linearly polarized photons

用于高能线偏振光子的对旋光计

• 批准号: 0653424
• 负责人: Branislav Vlahovic
• 金额: $ 6万
• 依托单位: North Carolina Central University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0653424&HistoricalAwards=false
• 关键词: Pair; polarimeter; energy; linearly; polarized

Intellectual Merits: In spite of 40 years of history, high energy photon polarimetry is an undeveloped field. At JLab energies all known methods have low analyzing power, and the absolute accuracy is below that required for the approved and anticipated physics programs. Currently, the only way to estimate the degree of photon polarization in Hall B is by fitting theoretical calculations to the collimated photon energy spectrum. The JLab physics program in Hall B and planned Hall D will significantly benefit from this new polarimeter, which will significantly reduce a major systematic experimental error in all approved and some planned experiments. The proposed polarimeter will have an experimental asymmetry of approximately 1.7 (analyzing power 26%) for an energy range from a few tens of MeV up to several GeV. This implies that for a beam intensity of 106 photons per second, such as at the JLab, a 1% statistical accuracy of the polarization measurement will require less then one hour of data taking. The polarimeter is simple in construction, compact, and its costs will be lower than for polarimeters built according to any other available method. Three prototypes were built and tested at Duke, BNL, SPring8 and JLab. The analyzing power was determined to be 19.2% for equal-energy pairs and 11.9% for all events during the test run at the Spring-8. The polarimeter was applied at JLab Hall B g8b experiment and it worked as predicted, there was no problem with high beam intensity and reconstruction of the events. Since the budget is reduced for more then 90% the scope of the work will be limited only to the education of the students that will have assigned projects related to the polarimeter physics. Any work planned related to the research or development of the polarimeter will be no performed, because of the lack of the support. Broader Impact: The proposed research and education program could result in increased competitiveness of the NCCU physics and science programs, and improved conditions for the faculty and student recruitment. The integration between research and education could be expanded with new courses and research programs designed to enrich current curriculum and bring more students into the original research. However the limited funding will allow us only to develop student research projects that will create an ambient for enhancing undergraduate computational program in science department, and recently approved graduate program in physics. The most significant impact of the project will be in providing highly qualified work force with highly skilled minorities and socially underrepresented groups. The original research in the fields of nuclear and computational physics, and computer modeling, could increase production of more competitive students. Emerging scientific advances and opportunities could also provide flexibility in career choices, adequately prepare our students for further graduate studies, and highlight the job opportunities for our graduates. Furthermore, we expect that this program will stimulate continuing expansion of training for African American graduate and undergraduate students.

智力优点：尽管有40年的历史，但高能量光子极化法是一个未开发的领域。在JLAB能量下，所有已知方法的分析能力都较低，并且绝对准确性低于批准和预期的物理计划所需的能力。 目前，估计B厅中光子极化程度的唯一方法是将理论计算拟合到准入的光子能谱。 B厅B和计划的H厅的JLAB物理计划将从这项新的偏光仪中大大受益，这将大大减少所有批准和一些计划实验的重大系统实验错误。 所提出的偏振仪的实验不对称性约为1.7（分析功率26％），其能量范围从几十MEV到几个GEV。这意味着，对于每秒106个光子的光束强度，例如在JLAB处，极化测量的1％统计精度将需要少于一小时的数据。 偏振仪的构造，紧凑，其成本将低于根据任何其他可用方法构建的极化计。 在Duke，BNL，Spring8和Jlab建造和测试了三个原型。 在春季8的测试运行期间，相等能力对的分析能力为19.2％，所有事件的分析能力为11.9％。偏振仪是在JLAB HALL B G8B实验中应用的，它正如预测的，远光强度和事件重建没有问题。由于预算降低了90％，因此工作范围将仅限于将分配与偏光仪物理学有关的项目的教育。由于缺乏支持，因此不会执行与偏光仪研究或开发有关的任何计划。 更广泛的影响：拟议的研究和教育计划可能会导致NCCU物理和科学计划的竞争力提高，并改善了教师和学生招聘的条件。 研究与教育之间的融合可以通过旨在丰富当前课程并将更多学生带入原始研究的新课程和研究计划来扩展。但是，有限的资金将使我们只能开发学生研究项目，这些项目将创建一个环境，以增强科学系的本科计算计划，并最近获得了物理学研究生计划。该项目的最重要影响将是为高技能的少数民族和社会代表性不足的团体提供高素质的劳动力。核和计算物理学领域以及计算机建模领域的最初研究可能会增加竞争激烈的学生的产量。新兴的科学进步和机会也可以为职业选择提供灵活性，充分为我们的学生做好了进一步的研究生学习的准备，并突出了我们毕业生的工作机会。此外，我们预计该计划将刺激非裔美国人毕业生和本科生的培训持续扩展。