GB/T 36129-2018 in English

1. Background and significance of standard formulation

GB/T 36129-2018 "Cathode luminescence imaging method for identification of jewellery and jade" is a national standard of the People's Republic of China, proposed by the Ministry of Natural Resources and managed by the National Technical Committee for Standardization of Jewellery and Jade. This standard fills the gap in cathode luminescence analysis methods in the field of jewellery and jade identification, and provides scientific basis and technical support for the identification of jewellery and jade and its optimized products.

2. Method principle and technical advantages

Cathode luminescence imaging method bombards the sample surface with high-energy electron beams to stimulate the sample to produce fluorescence of different wavelengths and intensities. According to the fluorescence color, distribution characteristics and its relationship with the crystal structure, the types, contents and structural defects of trace elements in jewellery and jade can be analyzed.

Table 1: Comparison of Cathodoluminescence and Traditional Fluorescence Analysis

3. Standard framework and technical requirements

The standard mainly includes the following contents:

• Scope: Applicable to the identification of jewelry and gemstones and their optimized products.
• Term definition: Clarifies key concepts such as cathodoluminescence, activator, and structural defects.
• Method principle: Based on the physical mechanism of fluorescence excitation by high-energy electron beams.
• Instrument: Including jewelry and gemstone cathodoluminescence instrument and scanning electron microscope equipped with cathodoluminescence accessories.

4. Implementation suggestions and practical applications

4.1 Operation precautions

• When adjusting the high voltage and beam current, the initial settings are 8kV and 100μA, and fine-tuned according to the sample luminescence effect.
• Avoid using too high a beam current for samples containing structured water or organic matter (such as opal and pearl).
• Clean the sample chamber regularly to prevent sputtering and coating.

4.2 Result Analysis Suggestions

• Compare and analyze with the cathode luminescence characteristic diagram in Appendix A.
• Refer to the trace element and color relationship table in Appendix B to comprehensively judge the sample properties.

4.3 Implementation Process

1. Instrument preparation: Turn on the vacuum pump and evacuate to the predetermined vacuum degree.
2. Sample placement: Place the sample in the sample chamber and adjust the electron beam position.
3. Parameter adjustment: Optimize high voltage and beam current to obtain stable characteristic fluorescence.
4. Result recording: Describe the color, intensity and distribution characteristics, and make a comprehensive judgment.