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As is well known, the scanning electron microscope is an essential research and testing instrument in the field of petroleum geology. It can be used to determine the type of organic matter precursor in sedimentary rocks, to study clay minerals, to examine calcareous microfossils, and to analyze reservoir rocks, playing a significant role in this industry. However, since many samples in the field of petroleum geology require sample preparation before being examined under a scanning electron microscope, the traditional method involves ordinary manual or mechanical grinding. But due to various damages such as mechanical scratches, contamination, and deformation on the surface that occur during grinding as a result of the tiny-scale structures within the samples, it is difficult to obtain their true morphology or to observe their actual internal microstructures. For example, in the development of shale gas, which has been highly promoted in recent years, the pores where gas is stored in samples such as shale, mudstone, and sandstone are usually at the nanometer or even angstrom scale. Therefore, due to the friability of these geological samples, it is hard to determine the true distribution of internal pores through ordinary manual or mechanical polishing. As a result, many users both domestically and internationally now opt for argon ion polishing devices to polish samples using argon ion beams, so that the pore structures at the microscale can be observed under a scanning electron microscope. Using an argon ion precision polishing device, a smooth cross-section can be obtained without causing mechanical damage to the sample. After being polished with an argon ion beam, rock or microporous samples can be analyzed using techniques such as scanning electron microscopy (SEM), thin-section petrography, and X-ray diffraction to determine their mineral composition, structure, and pore distribution. It is also possible to observe the reservoir structure within shale, quantitatively assess the pores in the reservoir, and determine the porosity. Argon ion polishers are primarily used in the shale gas industry to prepare samples with micronano-scale pores and samples made of various materials, both hard and soft. This helps to overcome issues such as pore clogging caused by mechanical grinding and polishing, contamination between different material types, and stress-induced damage to the samples during the grinding process. Given that samples in the petroleum geology industry contain organic materials as well as certain volatile substances, and that ion beam processing raises the surface temperature of the samples, the organic materials tend to volatilize, resulting in the formation of artificial pores. Additionally, since different materials have different coefficients of expansion, an increase in temperature generates thermal stress; the varying degrees of expansion of these materials can cause the pores to deform or even shrink, as well as lead to the formation of cracks, thereby preventing the acquisition of accurate structural information. Therefore, an argon ion polisher with low-temperature processing capabilities has become an indispensable tool. By using a liquid nitrogen cooling stage, the damage caused to the sample by thermal effects can be eliminated, thereby fundamentally solving the problem of thermal effects. Kerogen-rich oil shale is easily damaged during mechanical polishing; the use of an argon ion polisher allows its original structure to be preserved intact. The cross-section prepared using an argon ion polisher is shown in the figure below, illustrating the distribution of carbonates, silicates, pyrite, and other organic substances.