reflectance spectroscopy advantages and disadvantages

Infrared and Raman spectroscopy techniques have the ability to accurately reach conclusions from identification to treatments that have otherwise been time-consuming or impossible to achieve with traditional gemological tools, especially when they are paired and used in conjunction with each other. Since 1990 Innovatech Labs has provided materials testing with extremely fast turnaround. Copyright © 2016 Elsevier Inc. All rights reserved. As Raman, FTIR is nondestructive and does not need any sample preparation. XPS and ESCA are actually the same technique. While very versatile, XPS is not a good choice for all materials testing. 2002. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. Diffuse Reflectance Spectroscopy and Imaging. For example,  the study of the defects in diamonds to identify treatments and synthetics (FTIR),  the fast identification of practically any gem material, regardless if it is rough, measuring less than 1 mm or mounted (Raman). It’s also important to note that size can be a limiting factor depending on the sample. Samples must be compatible with high vacuum environment. used methods are diffuse reflectance (DRIFT) and specular reflectance (Figure 4). So, if your sample will outgas when placed under vacuum, XPS is not the right test for your needs. One of the most distinctive features of colorless CVD synthetic diamonds is the contamination of silicon occurring during the growth process. In natural unheated material the main chromium PL peak is narrow and centered at 685.5 nm while in heat treated spinel the such is broader and its ZPL, Zero Photon Line, is shifted towards higher wavelengths (Zagorevskii 1999). They are especially limiting when we need to test gems mounted in jewelry and objects, and we are unable to access them fully. Hughes, Richard W., and with Wimon Manorotkul and E. Billie Hughes. It sounds simple and quite easy to get a result, but we need to keep in mind that we are testing gems and they are cut and faceted with the purpose of interacting and reflecting with light. Contact us today for more information about XPS analysis or other testing services. The principal differences can be observed in the range of 2000-4200 cm-1 (Stockton, 1988). Copyright © 2020 Elsevier B.V. or its licensors or contributors. The quick screening of colorless/near to colorless synthetic CVD diamond, emerald or spinel (PL),  the identification of inclusions in gemstones (Confocal Micro-Raman), by detecting contaminants that would otherwise be undetectable to aid in the determination of heat treatment in corundum (FTIR),  and for many more critical gemological applications. Advantages of XPS or ESCA Analysis If surface chemistry or thickness is critical to product function and safety, XPS analysis is a proven choice. 3. It is likely the only gemological tool which can deliver a conclusive identification without the need for further testing. Traditionally it was only possible to do so by using microscopic observation. With advancing technology in more recent years, a Raman spectrometer paired with a microscope gives us the ability to identify gemstone inclusions using a common focal point through the optical path. Cutting a sample is not always an option and can lead to added contamination of the area of interest. https://doi.org/10.1111/j.1475-4754.1965.tb00896.x. “The Identification of Clarity Enhancements of Emeralds.”. Prior to the laser, the only other option available was the monochromator, which is sizable and expensive to produce (Scarani and Åström, n.d.). The Raman Spectrometer provides a very strong source that enables its detector to see and record this small portion of the scattered radiation. 2000. Being that the Raman fingerprint is exceptionally accurate and precise as a means of identification, it is not necessary to conduct further analysis in order to reach a reliable and conclusive result. (Hainschwang 2002). Disadvantages of Raman Spectroscopy. 1×10-9 Torr). The most commonly. 2009. Its high sensitivity is the main advantage of fluorometry. Methods involving diffuse reflectance, including diffuse reflectance spectroscopy and diffuse reflectance imaging are also introduced. Synthetic flux Alexandrite can be differentiated from its natural counterpart. The Fourier-Transform technique has many advantages over traditional infrared spectroscopy due to the use of the Michelson interferometer, such as its higher power output and the capability of quickly scanning all the frequencies of the infrared source at the same time (Åström and Scarani, n.d.). Encyclopedia of Spectroscopy and Spectrometry. Samples must be amenable to a high vacuum environment (ca. Since 1990 Innovatech Labs has provided materials testing with. Over the past 20 years, Raman spectroscopy has become more readily available due to the development of the laser, which has provided us with a compact and affordable, strong monochromatic light source that is needed to achieve the inelastic scattering. Raman and PL spectra are collected simultaneously with the same instrumentation, and Raman peaks may possibly appear in PL spectra if the emission peaks are not too pronounced (Eaton-Magana and Breeding 2016). Usually, only small items as rings can be tested.

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