Polarimeter for High Energy Photons

高能光子旋光仪

• 批准号: 0072391
• 负责人: Branislav Vlahovic
• 金额: $ 2.5万
• 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: 2000
• 资助国家: 美国
• 起止时间: 2000-09-15 至 2001-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0072391&HistoricalAwards=false
• 关键词: Polarimeter; Energy; Photons

0072391Vlahovid In many research facilities such as JLAB, LEGS, GRAAL, DESY, SAL, MAMI, and INS, which have scheduled experiments with polarized photon beam, there is a need for accurate polarization measurements in short time periods. Unfortunately at present, no adequate method is available at the higher energies characteristic of such facilities. At energies above ~ 600 MeV all known method have small analyzing power, and significant amount of time is required for polarization measurements. At the lower energies the pair production method off nuclei isknown to be the most promising. However, because the opening angle between the electron-positron pair decreases as the energy of the photon increases, this method has not been applied to higher energies. We propose to improve the pair production method at lower energies, and to extend it to higher energies, by taking advantage of new development in microstrip detectors technologies. The proposed polarimeter will have an analyzing power of the ~ 1.7 for a broad energy range, from few MeV up to several GeV. The proposed polarimeter is simple in construction and its costs will be lower than for polarimeters built on any of the other availablemethods.

在JLAB、LEGS、GRAAL、DESY、SAL、MAMI和INS等许多计划进行偏振光子束实验的研究机构中，都需要在短时间内进行精确的偏振测量。不幸的是，目前还没有适当的方法来处理这类设施的高能量特征。在~ 600 MeV以上的能量下，所有已知方法的分析能力都很小，并且需要大量的时间进行偏振测量。在能量较低的情况下，利用原子核产生对的方法被认为是最有前途的。然而，由于电子-正电子对之间的开口角随着光子能量的增加而减小，因此该方法尚未应用于高能量。我们建议利用微带探测器技术的新发展，在低能量下改进对的产生方法，并将其扩展到高能量。所提出的偏振计在从几MeV到几GeV的宽能量范围内具有~ 1.7的分析能力。所提出的偏振光计结构简单，其成本将低于任何其他可用方法上的偏振光计。