Application of Avantes Fiber Spectrometer in Rapid Diamond Detection

Introduction:

With the development of spectroscopy, spectrometers have been widely used in the online and offline measurement of gemstones. In particular, micro-spectrometers are used in the online high-speed measurement of gemstones. When conventional instruments, conventional methods and experience cannot solve the problem, modern high-tech testing instruments and analysis methods must be used to make accurate analysis and judgment on the actual condition of the measured jewelry.

1. Spectrometer Principle

The AvaSpec-2048 fiber spectrometer of Avantes Company in the Netherlands adopts a symmetrical optical path design with a focal length of 75mm, including a fiber connector (standard SMA interface, other types of interfaces can also be selected), a collimator, a diffraction grating, a focusing lens and a Sony ILX554 2048 pixel linear array CCD detector. The measurement wavelength range is 200-1100nm, the highest resolution is 0.04nm, and it provides USB1.1 or USB2.0 interface, RS-232 interface and I/O external trigger interface.

The advantage of fiber optic spectrometer lies in the modularity and flexibility of the system. The measurement speed of the micro-fiber spectrometer of Avantes Company in the Netherlands is very fast, making it suitable for online analysis. And because it uses a low-cost universal detector, the cost of the spectrometer is also greatly reduced, which greatly expands its application field.

2. Measuring test

color is one of the factors that determine whether a diamond is precious or not. The study found that natural and artificial diamonds can be compared within the wavelength range of 400-750nm. For type Ia natural diamonds, there are absorption peaks at 415 and 478nm, while artificial diamonds do not. For artificial diamonds, spectral lines appear at 592nm or 741nm. The value of natural diamonds and artificial diamonds differs by about 10 times. Of course, this method can also measure other gemstones, such as ruby, alexandrite and sapphire.

2.1 Typical device for diamond measurement

The typical device for diamond detection can be divided into two systems, one of which is suitable for laboratory measurement and measurement of loose diamonds, and the other is suitable for online rapid detection and measurement of mounted jewelry. The configuration diagrams are as follows:

Figure 2-Diamond Measurement

This system mainly consists of AvaSpec-2048 spectrometer, light source, optical fiber, integrating sphere and other accessories to form a complete system. It is convenient for you to detect various shapes of loose diamonds. [page]

Figure 2- Rapid Diamond Detection

This system is mainly suitable for rapid measurement of diamonds, such as worker detection on an assembly line, and various inlaid diamond jewelry.

2.2 Diamond Measurement Experiment

When measuring diamonds, you should first turn on the light source and preheat it for about 15 minutes before measurement to maintain the stability of the light source. Then, after setting the various parameters of the spectrometer, you can start measuring. When testing diamonds, the main focus is on the absorption peak at 415nm. Natural diamonds have obvious absorption peaks as shown in the following figure:

When performing rapid testing, this measurement time can be completed within a few seconds, and the data is reliable, so this detection method has a very large application space in rapid and large-scale testing.

3. Conclusion

From the perspective of the development of gem detection, rapid and scientific detection is an inevitable trend of its development! Avantes' fiber optic spectrometer is very suitable for this application. The instrument has the advantages of small size, easy to carry, comprehensive software functions and simple operation. And it has been adopted by the National Jewelry Testing Center of the Ministry of Land and Resources.

Avantes' fiber optic spectrometer is convenient for you to conduct fast and accurate diamond testing! (end)