论文标题
台湾光子源的软X射线AGM-AG-AGS RIXS光束线的开发
Development of the Soft X-ray AGM-AGS RIXS Beamline at Taiwan Photon Source
论文作者
论文摘要
我们报告了位于台湾光子源的软X射线谐振X射线散射（RIX）的高分辨率和高效光束线的开发。该梁线采用光学设计，该光学设计使用主动光栅单色器（AGM）和活动的光谱仪（AGS）来实现光栅分散剂的能量补偿原理。活跃的光栅用于减少散焦，昏迷和高阶畸变，并减少由热变形和光学抛光引起的斜率误差。 AGS安装在可旋转的花岗岩平台上，以在宽范围内具有散射角度的动量分辨的RIX测量。简要描述了为此梁线开发的几种高精度仪器。从此AGM-AGS光束线获得的最佳能量分辨率为530 eV的12.4 MeV，达到了42,000的分辨能力，而事件软X射线的带宽保持在0.5 eV。为了展示高分辨率RIX的科学影响，我们提供了一个在高温超导层蛋白酶的势头分辨RixS测量的示例，LA $ _ {2-x} $ sr $ _x $ _x $ _x $ cuo $ _4 $。测量结果揭示了超导酸奶中的$ _ {1G} $顶氧气子，为研究这些声子和电荷密度波之间的耦合打开了新的机会。
We report on the development of a high-resolution and highly efficient beamline for soft-X-ray resonant inelastic X-ray scattering (RIXS) located at Taiwan Photon Source. This beamline adopts an optical design that uses an active grating monochromator (AGM) and an active grating spectrometer (AGS) to implement the energy compensation principle of grating dispersion. Active gratings are utilized to diminish defocus, coma and higher-order aberrations as well as to decrease the slope errors caused by thermal deformation and optical polishing. The AGS is mounted on a rotatable granite platform to enable momentum-resolved RIXS measurements with scattering angle over a wide range. Several high-precision instruments developed in house for this beamline are briefly described. The best energy resolution obtained from this AGM-AGS beamline was 12.4 meV at 530 eV, achieving a resolving power 42,000, while the bandwidth of the incident soft X-rays was kept at 0.5 eV. To demonstrate the scientific impacts of high-resolution RIXS, we present an example of momentum-resolved RIXS measurements on a high-temperature superconducting cuprate, La$_{2-x}$Sr$_x$CuO$_4$. The measurements reveal the A$_{1g}$ apical oxygen phonons in superconducting cuprates, opening a new opportunity to investigate the coupling between these phonons and charge density waves.
