用极化晶体谱仪探测X射线极化度

为了研究等离子体各向异性及确定高温等离子体中电子束的存在,研制了X射线极化晶体谱仪,探讨了极化光谱学的理论,推演了X射线极化度的计算方法.谱仪能够在两个相互垂直的方向分别对X射线进行探测,垂直方向晶体分析器使用云母球面晶体,水平方向为PET平面晶体,摄谱元件采用成像板.在激光聚变研究中心2×10 J激光装置上进行了摄谱实验.实验结果表明,PET晶体分光效果理想,获得了铝的类He共振线(w)、磁四级M2跃迁x线、互组合跃迁y线以及禁戒谱线z线,适合于研究X射线极化光谱学；云母晶体得到铝的类He共振线,其伴线光谱不明显.分析了谱仪垂直方向信号微弱的原因,提出了改进极化晶体谱仪的方案.

Measurement of Polarization of X-ray with Polarization Spectrometer

For the research on anisotropy of plasma and ascertainment the presence of electron beams in high-temperature plasmas,a X-ray polarization spectrometer wasdesigned.The theory of the polarization spectroscopy was investigated and the ways of polarization calculation were presented.The polarization spectrometer could measure X-ray lines radiated by plasma in the directions of vertical and horizontal.In the vertical configuration the plane of dispersion of the crystal is spherical Mica and in the horizontal configuration the plane of dispersion of the crystal is flat PET.The X-ray spectra emitted from the planar aluminum target was photographed by using the polarization spectrometer with two image plates at the 2×10 J facilities in Research Center of Laser Fusion.The experimental result shows that the resonance line w,the magnetic quadrupole M2 line,the intercombination line y and the forbidden line z of He-like Al are obtained with PET crystal in the direction of horizontal.So the PET crystal is suitable for diagnosing soft X-ray spectroscopy.The resonance line w of He-like Al was obtained with Mica crystal and its satellite lines were vanished.At the same time the reasons were analyzed and the X-ray line polarization spectrometer was planned to redesign in order to detect the EBIT device.