Carmichael Justin R, Rother Gernot, Browning James F, Ankner John F, Banuelos Jose L, Anovitz Lawrence M, Wesolowski David J, Cole David R
Neutron Scattering Science Division, Oak Ridge National Laboratory, Tennessee 37831, USA.
Rev Sci Instrum. 2012 Apr;83(4):045108. doi: 10.1063/1.3697999.
A new high-pressure cell design for use in neutron reflectometry (NR) for pressures up to 50 MPa and a temperature range of 300-473 K is described. The cell design guides the neutron beam through the working crystal without passing through additional windows or the bulk fluid, which provides for a high neutron transmission, low scattering background, and low beam distortion. The o-ring seal is suitable for a wide range of subcritical and supercritical fluids and ensures high chemical and pressure stability. Wafers with a diameter of 5.08 cm (2 in.) and 5 mm or 10 mm thickness can be used with the cells, depending on the required pressure and momentum transfer range. The fluid volume in the sample cell is very small at about 0.1 ml, which minimizes scattering background and stored energy. The cell design and pressure setup for measurements with supercritical fluids are described. NR data are shown for silicon/silicon oxide and quartz wafers measured against air and subsequently within the high-pressure cell to demonstrate the neutron characteristics of the high-pressure cell. Neutron reflectivity data for supercritical CO(2) in contact with quartz and Si/SiO(2) wafers are also shown.
描述了一种用于中子反射测量（NR）的新型高压池设计，该高压池适用于高达50 MPa的压力和300 - 473 K的温度范围。这种池设计可引导中子束穿过工作晶体，而无需穿过额外的窗口或大量流体，从而实现高中子传输率、低散射背景和低束畸变。O形环密封适用于广泛的亚临界和超临界流体，并确保高化学稳定性和压力稳定性。根据所需压力和动量传递范围，直径为5.08 cm（2英寸）、厚度为5 mm或10 mm的晶片可与该池配合使用。样品池中的流体体积非常小，约为0.1 ml，这将散射背景和储存能量降至最低。描述了用于超临界流体测量的池设计和压力设置。展示了针对硅/氧化硅和石英晶片相对于空气以及随后在高压池内测量的NR数据，以证明高压池的中子特性。还展示了超临界CO₂与石英和Si/SiO₂晶片接触时的中子反射率数据。
