Development of portable, visible to infra-red spectrometer to measure geophysical and geochemical properties of rocks

在本研究中，我们开发了便携式，可见光到近红外光谱仪（Geosensor），其尺寸为228 × 308 × 172 mm，重量为8 kg，具有自己的光源，能够在8秒内测量从400 nm到2500 nm的宽波长范围内的反射强度，分辨率小于6 nm。第一年几乎全部用于建造仪器。在实验室和现场（室外）进行了重复测试，以评估其精密度，再现性和其他规格，并提高其可用性，以满足我们的要求。虽然在400 ~ 700 nm和2400 ~ 2500 nm波长范围内的再现性不够好，但在700 ~ 2400 nm波长范围内的分辨率和再现性都是可以接受的。从第二年下半年到第三年，我们进入了下一步，探索其在野外地球科学中的适用性。首先，我们测量了各种岩石类型的反射光谱， ...更多信息 D发现Geosensor能够识别位于550 nm和900 nm处的归因于Fe^3+的宽吸收峰，位于1100 nm处的归因于Fe^2+的宽吸收峰，位于1400和1900 nm处的归因于水的相对尖锐的吸收峰，位于1400、2200和2450 nm处的归因于-OH的尖锐的吸收峰，位于2350 nm处的尖锐峰归因于CO 3+<2->。接下来，我们通过实验研究了影响水的吸收峰强度（吸光度）的控制因素。结果表明，吸光度主要受含水量、粒径、不透明颗粒含量等因素的控制。结果进一步表明，如果我们将岩石类型限制为具有相对相似的含水量的细粒沉积物，我们可以基于Geosensor的快速测量来估计不透明颗粒的含量。将该方法应用于日本海实际沉积物岩心样品中有机碳和黄铁矿含量的测定，取得了满意的结果。少

In this research, we developed portable, visible to near infra-red spectrometer (Geosensor) which is 228x308x172 mm in size, 8 kg in weight, possessing its own light source, and capable of measuring reflection intensity over the wide wave length ranging from 400 nm to 2500 nm within 8 seconds with the resolution of less than 6 nm. The first year was spent almost entirely to construct the instrument. Tests both in the laboratory and in the field (out-door) were repeated to evaluate its precision, reproducibility, and other specification and to improve its usability to meet our requirements. Although the reproducibility within the wave range of 400 to 700 nm and 2400 to 2500 nm was not good enough, its resolution and reproducibility was both acceptable in the wave range of 700 to 2400 nm. From the later half of the second year to the third year, we moved to the next step to explore its applicability in the field geoscience. First, we measured reflective spectra for various rock types, an … More d found that Geosensor is capable of identifying broad absorb peaks situated at 550 nm and 900 nm attributable to Fe^<3+>, broad absorb peak situated at 1100 nm attributable to Fe^<2+>, relatively sharp absorb peaks at 1400 and 1900 nm attributable to water, sharp peaks situated at 1400,2200, and 2450 nm attributable to -OH,and sharp peak situated at 2350 nm attributable to CO3^<2->. Next we experimentally examined the controlling factors which influence the intensity of the absorb peak (absorbance) of water. The result suggests that the absorbance is mainly controlled by such factors as water content, grain size, and contents of opaque grains. The result further suggests that if we restrict the rock type as fine grained sediments with relatively similar water contents, we can estimate contents of opaque grains based on quick measurements by Geosensor. We applied this method to actual sediment core samples recovered from Japan Sea to estimate organic carbon and pyrite contents and obtained satisfactory result. Less