Changes

[[File:Fig09.jpg|thumb|300px|SEM photomicrographs of seal types.<ref name=Snider_1997>Snider, Robert M., John S. Sneider, George W. Bolger, and John W. Neasham, 1997, [http://archives.datapages.com/data/specpubs/mem67/ch01/ch01.htm Comparison of seal capacity determinations: Conventional cores vs. cuttings], in Surdam, R. C., ed., Seals, Traps, and the Petroleum System: [http://store.aapg.org/detail.aspx?id=749 AAPG Memoir 67], pp. 1-12.</ref>]]  

[[File:Fig09.jpg|thumb|300px|SEM photomicrographs of seal types.<ref name=Snider_1997>Snider, Robert M., John S. Sneider, George W. Bolger, and John W. Neasham, 1997, [http://archives.datapages.com/data/specpubs/mem67/ch01/ch01.htm Comparison of seal capacity determinations: Conventional cores vs. cuttings], in Surdam, R. C., ed., Seals, Traps, and the Petroleum System: [http://store.aapg.org/detail.aspx?id=749 AAPG Memoir 67], pp. 1-12.</ref>]]  

[[file:v2M102Ch1Fg1.jpg|thumb|300px|{{figure number|1}}Schematic diagram of the GEMINI^&trade; electron column (a) and the electron beam path in the column (b).<ref name=Huangetal_2013>Huang, Jason, Timothy Cavanaugh, and Boaz Nur, 2013, An introduction to SEM operational principles and geologic applications for shale hydrocarbon reservoirs, ''in'' W. Camp, E. Diaz, and B. Wawak, eds., Electron Microscopy of Shale Hydrocarbon Reservoirs: [http://store.aapg.org/detail.aspx?id=1197 AAPG Memoir 102], 260 pp.</ref>]]

[[file:v2M102Ch1Fg1.jpg|thumb|300px|{{figure number|1}}Schematic diagram of the GEMINI^&trade; electron column (a) and the electron beam path in the column (b).<ref name=Huangetal_2013>Huang, Jason, Timothy Cavanaugh, and Boaz Nur, 2013, An introduction to SEM operational principles and geologic applications for shale hydrocarbon reservoirs, ''in'' W. Camp, E. Diaz, and B. Wawak, eds., Electron Microscopy of Shale Hydrocarbon Reservoirs: [http://store.aapg.org/detail.aspx?id=1197 AAPG Memoir 102], 260 pp.</ref>]]

The same cross section was imaged with BSE1 with the Energy-selective backscatter (EsB) detector (Figure 4b). The image contrast (grayscale variation) reflects compositional variations (mean atomic number) of the sample. For example, the midgray represents silica matrix; the darker level represents organic matter. The brighter gray level reflects higher density carbonate phases, and the brightest gray level represents pyrite. Note the greater compositional contrast provided by the BS1 image (Figure 4b) over the SE2 image (Figure 4a). Although SE2 and BS1 images are capable of providing compositional information, auxiliary techniques, such as energy-dispersive x-ray spectrometry (EDS), are required to characterize elemental composition.

The same cross section was imaged with BSE1 with the Energy-selective backscatter (EsB) detector (Figure 4b). The image contrast (grayscale variation) reflects compositional variations (mean atomic number) of the sample. For example, the midgray represents silica matrix; the darker level represents organic matter. The brighter gray level reflects higher density carbonate phases, and the brightest gray level represents pyrite. Note the greater compositional contrast provided by the BS1 image (Figure 4b) over the SE2 image (Figure 4a). Although SE2 and BS1 images are capable of providing compositional information, auxiliary techniques, such as energy-dispersive x-ray spectrometry (EDS), are required to characterize elemental composition.

[[file:M102Ch1Fg5.jpg|thumb|300px|{{figure number|5}}A BSE2 image of gold (Au) nanoparticles showing crystallographic contrast.<ref name+Huangetal_2013 />]]

[[file:M102Ch1Fg5.jpg|thumb|300px|{{figure number|5}}A BSE2 image of gold (Au) nanoparticles showing crystallographic contrast.<ref name=Huangetal_2013 />]]

Compared to BSE1, for which the contrast is modulated by mean atomic number differences, BSE2 yield depends strongly on crystalline structures such as grain orientations. [[:file:M102Ch1Fg5.jpg|Figure 5]] shows a BSE2 image of gold (Au) nanoparticles. Contrast corresponding to different grains is revealed in the image despite all the chemically identical grains. Therefore, BSE2 electrons can be used to image crystallographic contrast in polycrystalline materials.

Compared to BSE1, for which the contrast is modulated by mean atomic number differences, BSE2 yield depends strongly on crystalline structures such as grain orientations. [[:file:M102Ch1Fg5.jpg|Figure 5]] shows a BSE2 image of gold (Au) nanoparticles. Contrast corresponding to different grains is revealed in the image despite all the chemically identical grains. Therefore, BSE2 electrons can be used to image crystallographic contrast in polycrystalline materials.