We present a new method for determining the spatial distribution and transport of water in porous media. It is based on the detection of both forward and backward scattered neutrons from the wet regions of the samples under investigation. The experimental set-up is based on a Pu-Be neutron source and He-3 neutron detector assemblies. The results obtained showed that back scattered neutrons are more sensitive than the forward scattered neutrons to determine water content. Moreover, both forward and back scattered neutrons are more sensitive than either back or forward neutrons for determining water content. The method was used to measure moisture transport in sand columns and brick samples. Forward and backward scattered neutrons from different wet regions along the water flow path (x) are recorded as the sample absorbs water. Water saturates the regions of the samples tested near the inlet of water faster than the others. The water front positions were found to follow the square root behavior of the absorption time, and capillary penetration coefficients were determined for the samples investigated. The developed method can be used to investigate water absorption at various flow rates in porous samples of various sizes.

我们提出了一种确定多孔介质中水的空间分布和运输的新方法。它基于对被调查样品的潮湿区域中向前和向后散射的中子的检测。实验装置基于Pu-Be中子源和He-3中子探测器组件。获得的结果表明，后向散射中子比向前向散射中子对确定水含量更敏感。而且，对于确定水含量，向前和向后散射的中子都比向后或向后中子更敏感。该方法用于测量砂柱和砖样品中的水分传输。当样品吸收水时，沿水流路径（x）记录了来自不同湿区的向前和向后散射的中子。水在进水口附近使测试区域浸水的速度比其他区域快。发现水前位置遵循吸收时间的平方根行为，并确定了所研究样品的毛细管渗透系数。所开发的方法可用于研究各种大小的多孔样品在各种流速下的吸水率。