Acquisition of a Particle Size Analyzer for Geochemical Research at Dartmouth College

小行星9727362 这笔赠款为达特茅斯学院地质系购置一台基于X射线衰减的粒度分析仪提供部分支持。 该设备通过测量当颗粒在重力作用下通过液体介质时穿过样品的X射线的时变衰减来测量样品中的连续颗粒尺寸分布。 测量的基本原理依赖于颗粒沉降的斯托克斯定律;较大的颗粒比较小的颗粒沉降得更快（忽略颗粒形状和密度变化）。 该粒度分析仪将用于各种资助的研究项目，既用于粒度分析，也作为一种替代矿物分离技术。 对沸石矿物与周围流体之间的大小相关同位素交换、大小相关/表面积相关硅酸盐矿物风化速率和海洋沉积物来源研究的研究将利用仪器快速测量大范围粉砂和粘土大小颗粒（100微米-10纳米）的连续粒度分布的能力。 达特茅斯的几位研究人员将利用这种设备，并将让本科生参与各自研究项目的分析阶段。 ***

9727362 Feng This grant provides partial support of the acquisition costs of an X-ray attenuation-based particle size analyzer for the geology Department at Dartmouth College. This device measures continuous particle size distribution in samples by measuring the time varying attenuation of X-rays passing through samples as particles fall under the force of gravity through a liquid medium. The basic principle of the measurement relies on Stokes' Law of particle settling; larger particles settle more rapidly (neglecting particle shape and density variations) than smaller particles. The particle size analyzer will be used for a variety of funded research projects both for grain size analysis and as an alternative mineral separation technique. Studies of size- dependent isotopic exchange between zeolite minerals and surrounding fluids, size-dependent/surface area dependent silicate mineral weathering rates and provenance studies of marine sediments will take advantage of the instruments ability to rapidly measure continuous grain size distributions over a wide range of silt and clay sized particles (100 microns-10 nm). Several researchers at Dartmouth will make use of this equipment and will involve undergraduate students in the analytical phases of their respective research programs. ***