Reflective light fluid inclusion freezing laser denudation pool

Abstract

The invention provides a reflected light fluid inclusion freezing laser denudation pool, and belongs to the technology of single fluid inclusion component analysis in the field of earth science. The device is mainly composed of a shell, a freezing cavity, a denudation cavity and a top cover. The freezing cavity is located at the bottom of the shell and made of pure silver materials, the top of the cavity is subjected to mirror polishing treatment, and the cavity is connected with a liquid nitrogen tank and a liquid nitrogen pump through Teflon hoses. The denudation cavity is positioned above the liquid nitrogen cavity, is provided with a standard sample mounting hole, is spindle-shaped, is provided with an air inlet and an air outlet at two ends, and is connected to a carrier gas pipeline. A calcium fluoride glass window is arranged on the top cover and allows 193nm laser to penetrate through. According to the invention, the silver freezing cavity is adopted to ensure the required cooling effect; and meanwhile, the mirror surface design at the top of the freezing cavity converts light rays emitted by the reflected light microscope into transmission light rays, so that the fluid inclusion to be detected can be accurately observed and positioned without depending on a conventional transmission light system.

Description

Technical Field

[0001] The present invention relates to the technical field of laser ablation inductively coupled plasma mass spectrometry analysis, and particularly to a reflected light fluid inclusion freezing laser ablation cell. Background Art

[0002] Fluid inclusions are important tools for studying the properties and compositions of geological fluids, and their chemical compositions can directly reflect the compositional information of ore-forming fluids. Traditional analysis methods usually involve crushing the entire sample to open the contained inclusions, eluting with chemical reagents, and then analyzing the composition of the eluate. The results obtained by this method are the average compositions of all fluid inclusions in the sample. Due to the generally multi-stage formation characteristics of fluid inclusions, such mixed composition results are difficult to accurately reflect the composition of ore-forming fluids. In recent years, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) technology has gradually been applied to the composition detection of individual fluid inclusions and has become a cutting-edge technology in this field.

[0003] Since fluid inclusions usually form in high-temperature and high-pressure environments deep underground, the pressure inside the inclusions is relatively high, which may cause the inclusions to rupture during the laser ablation process, resulting in uncontrolled splashing of their contents, thereby affecting the accuracy of quantitative analysis. To solve this problem, researchers have adopted the liquid nitrogen freezing method, freezing the inclusions before laser ablation. However, in these methods, the observation of inclusions must rely on a transmitted light microscope with a sub-mounted light source; this requires the setting of a light passing hole on an opaque freezing stage. However, to ensure the freezing effect, the light passing holes of these devices are usually very small, providing a field of view of less than 2 millimeters. It is very difficult to observe and locate even smaller fluid inclusions through such a small light passing hole. In addition, most existing laser ablation devices move the ablation cell as a whole to move the sample, and it is impossible to precisely move the sample within the ablation cell, which makes it difficult to efficiently locate and ablate specific fluid inclusions. At the same time, traditional devices can only analyze the inclusions in a small-sized sample at a time. If the sample needs to be changed, the ablation cell has to be frequently opened, which not only reduces the analysis efficiency, but also affects the stability of the mass spectrometer state and the accuracy of the analysis results. Summary of the Invention

[0004] In view of this, the present invention provides a reflected light fluid inclusion freezing laser ablation cell, which can solve the problems of freezing and locating inclusions during the process of laser ablation composition analysis of fluid inclusions.

[0005] The present invention provides a reflection light fluid inclusion freezing laser ablation cell. The device mainly consists of a housing, a freezing chamber, an ablation chamber and a top cover. The freezing chamber is located at the bottom of the housing and is made of pure silver. Using liquid nitrogen as the refrigeration medium, the top of the chamber is mirror-polished and connected to a liquid nitrogen tank and a liquid nitrogen pump through a Teflon hose. The ablation chamber is installed above the freezing chamber and is provided with a standard sample mounting hole. The chamber is spindle-shaped, and air inlet holes and air outlet holes are provided at both ends and are connected to a carrier gas pipeline. The top cover is equipped with a calcium fluoride glass window that allows 193 nm laser light to pass through. In the present invention, pure silver with high thermal conductivity and high reflectivity is used to make the freezing chamber to ensure the required cooling effect and reflective effect. When in use, the downward light emitted by the microscope, after passing through the thin slice of the inclusion sample, is reflected by the mirror-polished top surface of the freezing chamber. After the downward light is reflected into transmitted light, it passes through the sample again and returns to the microscope, so as to achieve accurate observation and positioning of the fluid inclusions to be measured without relying on a conventional bottom-mounted transmitted light system.

[0006] The present invention adopts the following technical solutions:

[0007] A reflection light fluid inclusion freezing laser ablation cell, comprising a housing, a freezing chamber, an ablation chamber and a top cover;

[0008] The housing includes a semi-cylindrical shell and a square bottom plate; a liquid nitrogen inlet hole, a liquid nitrogen outlet hole, a carrier gas inlet pipe and a carrier gas outlet pipe are provided on the side of the cylindrical shell, and the square bottom plate is located at the bottom of the semi-cylindrical shell, and the square bottom plate is provided with mounting holes.

[0009] Sealing bolt holes are provided on the side of the top of the housing for sealing connection with the top cover, and an annular fluororubber seal ring is provided at the top edge of the semi-cylindrical shell.

[0010] The freezing chamber is a hollow flat cylindrical chamber, made of pure silver, and the top is mirror-polished; the inside of the freezing chamber is designed as a spiral winding channel, and the inlet and outlet of the channel are respectively connected to the liquid nitrogen inlet pipe and the liquid nitrogen outlet pipe on the side of the freezing chamber. The liquid nitrogen inlet pipe and the liquid nitrogen outlet pipe are respectively connected to a liquid nitrogen tank and a liquid nitrogen pump.

[0011] A temperature measuring probe is installed inside the freezing chamber and connected to an external temperature control meter.

[0012] The ablation chamber is installed inside the housing. A circular hole with the same diameter as the freezing chamber is provided at the center of the ablation chamber. The freezing chamber is nested and installed inside the ablation chamber. After assembly, the bottom surface of the ablation chamber is flush with the mirror surface of the top of the freezing chamber. The chamber of the ablation chamber is spindle-shaped, and carrier gas inlet holes and outlet holes are provided at both ends of the ablation chamber, which are respectively connected to the carrier gas inlet pipe and the carrier gas outlet pipe of the housing. A standard sample mounting hole is provided on one side of the ablation chamber close to the air outlet hole.

[0013] The top cover is a hollow ring, and a calcium fluoride glass window is installed inside the ring to ensure the transmission of 193 nm laser. Dense exhaust holes are provided above the calcium fluoride glass window on the inner side of the ring. The exhaust holes are connected to the hollow pipe inside the ring. The hollow pipe is connected from the intake pipe to the waste gas pipe of the liquid nitrogen pump. During use, dry waste gas is discharged through the exhaust holes and blows the surface of the calcium fluoride glass window to prevent fogging and frosting.

[0014] Compared with the prior art, the present invention has the following advantages: The freezing chamber does not need to rely on the traditional bottom-mounted light source transmission light system. Through the top mirror polishing design, the downward light emitted by the reflected light microscope can be converted into upward transmitted light, so as to achieve the same observation effect as the traditional transmitted light microscope. The design of the freezing chamber without a light passing hole not only provides a super-large observation field of view, but also ensures excellent freezing effect. This design breaks the limitation of the field of view size of the traditional light passing hole freezing device, making the observation and movement of samples more free and convenient. In addition, samples can be placed on the entire top of the freezing chamber of the present device, and multiple small-sized samples or extra-large-sized samples can be tested simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is the overall structural schematic diagram of the present invention;

[0016] Figure 2 is the structural schematic diagram of the freezing chamber of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The embodiments of the present invention will be further described below with reference to the drawings

[0018] Reference to liquid nitrogen pump Figure 1 , a reflected light fluid inclusion freezing laser ablation cell, comprising a housing 1, a freezing chamber 2, an ablation chamber 3 and a top cover 4;

[0019] The housing 1 is the main structure of the ablation cell, which is composed of a semi-cylindrical shell 18 and a square bottom plate 19 as a whole. A liquid nitrogen inlet hole 5, a liquid nitrogen outlet hole 6, a carrier gas inlet pipe 14 and a carrier gas outlet pipe 15 are provided on the side of the cylindrical shell 18. The square bottom plate 19 is located at the bottom of the semi-cylindrical shell 18. The square bottom plate 19 is provided with four mounting holes 20 for fixing the device. The outer diameter of the carrier gas inlet pipe 14 is 4.5 mm and the inner diameter is 0.8 mm. The outer diameter of the carrier gas outlet pipe 15 is 4.5 mm and the inner diameter is 3 mm to ensure a good flushing effect. A sealing bolt hole 21 is provided on the side of the top of the housing 1, and an annular fluororubber sealing ring 22 is provided at the top edge of the semi-cylindrical shell 18.

[0020] Reference Figure 1 and Figure 2, the freezing chamber 2 is a hollow flat cylindrical cavity with a diameter of 20 mm, a thickness of 5 mm, and a wall thickness of 1 mm; the freezing chamber 2 is made of pure silver and its top is mirror-polished; the interior of the freezing chamber 2 is designed as a spiral winding channel to improve heat exchange and refrigeration effects; the inlet and outlet of the channel are respectively connected to the liquid nitrogen inlet pipe 9 and the liquid nitrogen outlet pipe 10 welded to the side of the freezing chamber 2. The liquid nitrogen inlet pipe 9 and the liquid nitrogen outlet pipe 10 are respectively connected to a liquid nitrogen tank and a liquid nitrogen pump.

[0021] Reference Figure 1 and Figure 2 , a temperature measuring probe 11 is installed inside the freezing chamber 2 and connected to an external temperature control meter.

[0022] Reference Figure 1 , the ablation chamber 3 is installed inside the housing 1. There is a round hole with the same diameter as the freezing chamber 2 at the center of the ablation chamber 3. The freezing chamber 2 is nested and installed inside the ablation chamber 3. After assembly, the bottom surface of the ablation chamber 3 is flush with the top mirror surface of the freezing chamber 2. The cavity of the ablation chamber 3 is spindle-shaped. There are carrier gas inlet holes 12 and outlet holes 13 at both ends of the cavity of the ablation chamber 3, which are respectively connected to the carrier gas inlet pipe 14 and the carrier gas outlet pipe 15 of the housing 1. A standard sample mounting hole 16 is provided on one side of the ablation chamber 3 close to the inlet hole 12.

[0023] Reference Figure 1 , the top cover 4 is a hollow ring. A calcium fluoride glass window 17 is installed inside the ring to ensure transmission of 193 nm laser. Densely arranged exhaust small holes 18 are provided above the calcium fluoride glass window 17 on the inner side of the ring. The exhaust small holes 18 are connected to the hollow pipe inside the ring. The hollow pipe leads to the waste gas pipe of the liquid nitrogen pump through the inlet pipe 19. During use, dry waste gas is discharged through the exhaust small holes 18 and blows the surface of the calcium fluoride glass window 17 to prevent fogging and frosting.

[0024] Reference Figure 1 , the outer cross-section of the top cover 4 is wedge-shaped to achieve sealing by pressing the housing with a locking bolt.

[0025] Reference Figure 1 , the device housing 1, the ablation chamber 3, and the top cover 4 are all made by 3D printing technology to ensure precise machining of complex internal structures.

[0026] Reference Figure 1 , the specific implementation steps are as follows:

[0027] 1. Before analysis, connect the liquid nitrogen inlet pipe 9 and the outlet pipe 10 to a liquid nitrogen tank and a liquid nitrogen pump, connect the carrier gas inlet pipe 14 to the carrier gas cylinder pipeline, connect the carrier gas outlet pipe 15 to a mass spectrometer, and connect the waste gas pipe of the liquid nitrogen pump to the inlet pipe 19 of the top cover 4.

[0028] 2. Place the sample thin section containing the inclusion to be measured and the fluid inclusion standard sample on the mirror surface of the freezing chamber 2 in the middle of the ablation chamber 3, install the solid standard sample target in the standard sample installation hole 16, cover the top cover 4, and tighten the locking bolt;

[0029] 3. After the ablation cell is sealed, open the carrier gas to purge the residual air inside the ablation chamber to avoid sample frosting during the subsequent freezing process;

[0030] 4. After purging, turn on the microscope reflected light system to find the inclusion to be measured;

[0031] 5. After the inclusion to be measured is located, turn on the liquid nitrogen pump switch, control the liquid nitrogen pump to slowly draw in liquid nitrogen, and monitor the temperature and freezing effect through the temperature control meter and the microscope;

[0032] 6. After observing that the inclusion to be measured is frozen, laser ablation composition analysis can be started.

Claims

1. A reflection light fluid inclusion freezing laser ablation cell, characterized in that It includes a housing (1), a freezing chamber (2), an ablation chamber (3) and a top cover (4); On the side of the housing (1), there are a liquid nitrogen inlet hole (5), a liquid nitrogen outlet hole (6), a carrier gas inlet pipe (7) and a carrier gas outlet pipe (8); The top of the housing (1) is hermetically connected to the top cover (4); The top of the freezing chamber (2) is processed by mirror polishing; the inside of the freezing chamber (2) is designed as a spiral detour channel, and the inlet and outlet of the channel are respectively connected to the liquid nitrogen inlet pipe (9) and the liquid nitrogen outlet pipe (10) on the side of the freezing chamber (2); the liquid nitrogen inlet pipe (9) and the liquid nitrogen outlet pipe (10) pass through the liquid nitrogen inlet hole (5) and the liquid nitrogen outlet hole (6) on the side of the housing (1), and are respectively connected to a liquid nitrogen tank and a liquid nitrogen pump; A temperature measuring probe (11) is installed inside the freezing chamber (2) and connected to an external temperature control meter; The ablation chamber (3) is installed inside the housing (1). There is a round hole with the same diameter as the freezing chamber (2) in the center of the ablation chamber (3). The freezing chamber (2) is nested and installed inside the ablation chamber (3). After assembly, the bottom surface of the ablation chamber (3) is flush with the top mirror surface of the freezing chamber (2). There are a carrier gas inlet hole (12) and an air outlet hole (13) at both ends of the ablation chamber (3) cavity, which are respectively connected to the carrier gas inlet pipe (14) and the carrier gas outlet pipe (15) of the housing (1). A standard sample mounting hole (16) is provided on one side of the ablation chamber (3) close to the inlet hole (12); The top cover (4) is a hollow ring, and a calcium fluoride glass window (17) is installed inside the ring; a densely arranged exhaust small hole (18) is provided above the calcium fluoride glass window (17) on the inner side of the ring. The exhaust small hole (18) is connected to the hollow pipeline inside the ring. The hollow pipeline is connected to the waste gas pipeline of the liquid nitrogen pump from the inlet pipe (19). During use, dry waste gas is discharged through the exhaust small hole (18) and blows the surface of the calcium fluoride glass window (17) to prevent fogging and frosting.

2. A reflection light fluid inclusion freezing laser ablation cell according to claim 1, characterized in that, The housing (1) includes a semi-cylindrical shell (18) and a square bottom plate (19); the side of the cylindrical shell (18) is provided with a liquid nitrogen inlet hole (5), a liquid nitrogen outlet hole (6), a carrier gas inlet pipe (14) and a carrier gas outlet pipe (15). The square bottom plate (19) is located at the bottom of the semi-cylindrical shell (18), and the square bottom plate (19) is provided with mounting holes (20); Sealing bolt holes (21) are provided on the side of the top of the housing (1) for hermetically connecting with the top cover (4), and an annular fluororubber sealing ring (22) is provided at the top edge of the semi-cylindrical shell (7).

3. A reflected light fluid inclusion freezing laser ablation cell according to claim 1, characterized in that, The freezing chamber (2) is a hollow flat cylindrical cavity, and the freezing chamber (2) is made of pure silver; 4. A reflected light fluid inclusion freezing laser ablation cell according to claim 1, characterized in that, The cavity of the ablation chamber (3) is spindle-shaped.

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