Small angle X-ray scattering measurements for expanded fluid Se near the critical point
Small angle X-ray scattering measurements for expanded fluid Se near the critical point
复制标题
临界点附近膨胀流体Se的小角X射线散射测量
DOI：
10.1016/s0022-3093(99)00286-0
复制
发表时间：
1999
影响因子：
3.5
通讯作者：
K. Tamura
中科院分区：
文献类型：
--
作者：
M. Inui;Yasufumi Oh'ishi;Ichiro Nakaso;M. H. Kazi;K. Tamura
小角x射线散射（SAXS）测量研究了膨胀流体Se临界点附近的密度波动。实验是用我们设计的多晶蓝宝石电池和高压容器进行的。该容器有一个用于入射x射线束的菱形窗口和一个用于散射光束的Be窗口。通过对氦气作为传压介质的测量，推导出了绝对散射强度。流体Se在1630℃时SAXS强度的压力变化表明，在401 bar时最大强度刚好低于临界密度等线。这是第一次观察到流体硒的临界散射，并从Ornstein-Zernike图中获得了19±3 Å的相关长度。
Small angle X-ray scattering (SAXS) measurements have been carried out to investigate density fluctuations near the critical point of expanded fluid Se. The experiments were performed using a polycrystalline sapphire cell of our design and a high pressure vessel. The vessel has a diamond window for an incident X-ray beam and a Be window for the scattered beams. The absolute scattering intensity was deduced from the measurements on the He gas used as the pressure transmitting medium. The pressure variation of the SAXS intensity for fluid Se at 1630°C shows a maximum intensity at 401 bar just below the isochor of the critical density. This is the first observation of critical scattering for fluid Se and a correlation length of 19 ± 3 Å was obtained from an Ornstein–Zernike plot.