Polarimeter for High Energy Photons

0072391 Vlahovid在许多研究机构中，例如JLAB、LEGS、GRAAL、DESY、SAL、MAMI和INS，它们已经安排了使用偏振光子束的实验，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可用于这些设施的高能量特性。在高于~ 600 MeV的能量下，所有已知的方法具有小的分析能力，并且偏振测量需要大量的时间。 在较低的能量下，离核产生电子对的方法被认为是最有前途的方法。然而，由于电子-正电子对之间的张角随着光子能量的增加而减小，因此该方法尚未应用于更高的能量。我们建议在较低的能量，提高对生产方法，并将其扩展到更高的能量，利用微带探测器技术的新发展。建议的偏振计将有一个分析能力的~ 1.7的一个广泛的能量范围内，从几兆电子伏到几个GeV。所提出的旋光仪结构简单，其成本将低于任何其他可用的方法建立的旋光仪。

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.