Yakubova Galina, Kavetskiy Aleksandr, Prior Stephen A, Torbert H Allen
National Soil Dynamics Laboratory, Agricultural Research Service, United States Department of Agriculture;
National Soil Dynamics Laboratory, Agricultural Research Service, United States Department of Agriculture.
J Vis Exp. 2017 Aug 24(126):56270. doi: 10.3791/56270.
The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of gamma rays created when neutrons interact with soil elements. The main parts of the INS system are a pulsed neutron generator, NaI(Tl) gamma detectors, split electronics to separate gamma spectra due to INS and thermo-neutron capture (TNC) processes, and software for gamma spectra acquisition and data processing. This method has several advantages over other methods in that it is a non-destructive in situ method that measures the average carbon content in large soil volumes, is negligibly impacted by local sharp changes in soil carbon, and can be used in stationary or scanning modes. The result of the INS method is the carbon content from a site with a footprint of ~2.5 - 3 m in the stationary regime, or the average carbon content of the traversed area in the scanning regime. The measurement range of the current INS system is >1.5 carbon weight % (standard deviation ± 0.3 w%) in the upper 10 cm soil layer for a 1 hmeasurement.
本文所述的非弹性中子散射（INS）方法在土壤碳分析中的应用基于对中子与土壤元素相互作用时产生的伽马射线的记录和分析。INS系统的主要部件包括脉冲中子发生器、碘化钠（铊）伽马探测器、用于分离INS和热中子俘获（TNC）过程产生的伽马谱的分立电子设备，以及用于采集伽马谱和处理数据的软件。该方法相对于其他方法具有若干优势，因为它是一种无损原位方法，可测量大体积土壤中的平均碳含量，受土壤碳局部急剧变化的影响可忽略不计，并且可用于静态或扫描模式。INS方法的结果是在静态模式下足迹约为2.5 - 3米的场地的碳含量，或扫描模式下遍历区域的平均碳含量。当前INS系统的测量范围是在10厘米厚的上层土壤中进行1小时测量时，碳重量百分比>1.5%（标准偏差±0.3 w%）。
