New diamond anvil cells for gigahertz ultrasonic interferometry and X-ray diffraction
New diamond anvil cells for gigahertz ultrasonic interferometry and X-ray diffraction
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用于千兆赫超声干涉测量和 X 射线衍射的新型金刚石砧座
DOI：
10.2138/am-2000-2-303
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发表时间：
2000
影响因子：
3.1
通讯作者：
H. Reichmann
中科院分区：
文献类型：
--
作者：
W. Bassett;H. Reichmann
本文设计了两种新的金刚石对顶砧，用于单晶样品的超声和X射线衍射测量，测量压力高达6 GPa和250 °C。在产生和传输相干GHz的超声波信号与波长的数量级的微米的进步，现在使得它实际测量样品的弹性性能小到足以受到压力和温度在金刚石砧单元。信号从一个薄的传感器通过一个蓝宝石缓冲杆耦合到一个金刚石砧的手段的力量。信号穿过金刚石砧并进入单晶样品，该单晶样品通过水泥、粘附或通过法向力耦合到砧面。从单晶的近面和远面反射的叠加波的干涉被用来测量声波在样品中的传播时间。金刚石砧座单元中的一个采用常规几何形状，其中X射线通过金刚石砧座进入。另一个为X射线提供了与负载轴成高角度的通道，使得它们不需要通过金刚石砧，因此可以在缓冲棒就位时进入样品。这两种金刚石压砧单元都可以使用四圆测角仪在几个不同的方向上测量d间距。该功能用于检测和校正样品从测角仪中心的位移。在相同的压力-温度条件下测量行进时间和晶格参数允许将行进时间转换为速度，并且可以提供联立状态方程，然后可以使用该状态方程来独立确定压力与晶格参数。这提供了一个主要的压力规模
Abstract Two new diamond anvil cells have been designed for ultrasonic and X-ray diffraction measurements on a single crystal sample up to 6 GPa and 250 °C. Advances in the generation and transmission of coherent GHz ultrasonic signals with wavelengths of the order of micrometers now make it practical to measure elastic properties of samples small enough to be subjected to pressure and temperature in diamond anvil cells. The signal is carried from a thin transducer through a sapphire buffer rod coupled to one of the diamond anvils by means of force. The signal traverses the diamond anvil and enters the single crystal sample which is coupled to the anvil face by cement, adhesion, or by a normal force. Interference of superimposed waves reflected from the near and far faces of the single crystal is used to measure travel time of the sound waves in the sample. One of the diamond anvil cells employs the conventional geometry in which access for the X-rays is through the diamond anvils. The other provides access for X-rays at high angles to the load axis so that they do not need to pass through the diamond anvils and can therefore have access to the sample while the buffer rod is in place. Both diamond anvil cells make it possible to measure d-spacings at several different orientations using a four-circle goniometer. This capability is used for detecting and correcting displacement of the sample from the center of the goniometer. Measurement of travel times and lattice parameters at the same pressure-temperature conditions allows conversion of travel times to velocities and can provide simultaneous equations of state, which EOS can then be used to make an independent determination of pressure vs. lattice parameter. This provides a primary pressure scale