研究目的
Investigating the effect of laser radiation on the surface and volume of natural quartz to determine the composition of fluid inclusions, and evaluating the interaction of the texture and structural features of quartz raw materials with laser radiation during the evaporation of natural quartz.
研究成果
The proposed method for determining the composition of elemental fluid inclusions by comparing the signals of a clean region and a region with clusters of small PVs makes it possible to estimate the elemental composition of small PVs, improve the positional accuracy of the analysis (localization of the evaporation zone), and to a large extent eliminate the deterioration of the stability of the analytical signal by the material from the chips of the sample.
研究不足
The transparency of pure quartz for the wavelength of 213 nm leads to an uneven effect of radiation on the selected region, which distorts the localization of this effect. The amount of aerosol obtained by the laser action is proportionally related to the radiation power. There is a minimum power value at which the sensitivity of the device is not sufficient to register the selected elements.
1：Experimental Design and Method Selection:
The study involved the use of laser ablation complex (LA) based on a NexION 300D quadrupole mass spectrometer and a laser platform based on a solid-state Nd:YAG laser with an operating wavelength of 213 nm NWR-213. The pulse energy was 9.3 J/cm2, the pulse repetition rate was 5 Hz, the number of pulses was 400, the laser beam diameter was 50 μm, the pulse duration was 4 ns, the carrier gas flow rate was 0.6 l/min He, and the carrier gas flow rate was 0.8 l/min Ar; the other gases were Plasma/Cool and Auxiliary Gas 18 L/min and 2 L/min Ar, respectively; plasma power, 1400 W; and signal accumulation time, 2 ms/cell.
2：The pulse energy was 3 J/cm2, the pulse repetition rate was 5 Hz, the number of pulses was 400, the laser beam diameter was 50 μm, the pulse duration was 4 ns, the carrier gas flow rate was 6 l/min He, and the carrier gas flow rate was 8 l/min Ar; the other gases were Plasma/Cool and Auxiliary Gas 18 L/min and 2 L/min Ar, respectively; plasma power, 1400 W; and signal accumulation time, 2 ms/cell. Sample Selection and Data Sources:
2. Sample Selection and Data Sources: Two varieties of quartzites of the Bural-Sardyk deposit were investigated: superquartzite (rocks of uneven-grain structure) and fine-grained quartzite (quartz grains of slightly elongated shape and more even boundaries).
3：List of Experimental Equipment and Materials:
Olympus BX 51 microscope equipped with a PixeLink 1394 camera and QImaging MicroPublisher
4：0 RTV software, laser ablation complex (LA) based on a NexION 300D quadrupole mass spectrometer (PerkinElmer, United States) and a laser platform based on a solid-state Nd:
YAG laser with an operating wavelength of 213 nm NWR-213 (New Wave Research, United States).
5：Experimental Procedures and Operational Workflow:
Microscopic studies of transparently polished quartzite plates were performed in transmitted and reflected light. The effect of laser radiation on the surface of natural quartz was studied using the laser ablation complex.
6：Data Analysis Methods:
The content of potassium, lithium, boron, and aluminum in the optically clean regions and areas of FI accumulations were compared using NIST SRM 612 synthetic glass as the standard.
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