A reflective optical fluid encapsulant cryogenic laser ablation cell

Abstract

This invention provides a cryo-laser ablation chamber for reflected light fluid inclusions, belonging to the field of geosciences for the analysis of the composition of single fluid inclusions. The device mainly consists of an outer shell, a cryo chamber, an ablation chamber, and a top cover. The cryo chamber, located at the bottom of the outer shell, is made of pure silver, and its top is mirror-polished and connected to a liquid nitrogen tank and pump via a Teflon hose. The ablation chamber, located above the liquid nitrogen chamber, has a standard sample mounting hole. The chamber is spindle-shaped and has inlet and outlet ports at both ends, connected to a carrier gas pipeline. The top cover is equipped with a calcium fluoride glass viewing window, allowing 193nm laser light to pass through. This invention uses a silver cryo chamber to ensure the required cooling effect; simultaneously, the mirror design at the top of the cryo chamber converts the light emitted by the reflected light microscope into transmitted light, thus enabling precise observation and positioning of the fluid inclusions under test without relying on conventional transmitted light systems.

Description

Technical Field

[0001] This invention relates to the field of laser ablation inductively coupled plasma mass spectrometry (ICP-MS) analysis technology, and more particularly to a cryo-laser ablation cell for reflected light fluid inclusions. Background Technology

[0002] Fluid inclusions are crucial tools for studying the properties and composition of geological fluids, as their chemical composition directly reflects the compositional information of ore-forming fluids. Traditional analytical methods typically involve pulverizing the entire sample to open the contained inclusions, eluting with chemical reagents, and then analyzing the composition of the eluent. This method yields the average composition of all fluid inclusions in the sample. However, since fluid inclusions often form in multiple stages, 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) has been increasingly applied to the compositional detection of individual fluid inclusions, becoming a cutting-edge technology in this field.

[0003] Because fluid inclusions typically form in high-temperature, high-pressure environments deep underground, the internal pressure of these inclusions is significant. This can cause them to rupture during laser ablation, resulting in uncontrolled ejection of their contents and affecting the accuracy of quantitative analysis. To address this issue, researchers employed liquid nitrogen freezing to freeze the inclusions before laser ablation. However, these methods require observation of the inclusions using a transmission light microscope with a downward-facing light source. This necessitates the placement of a light aperture on an opaque freezing stage, but to ensure effective freezing, these apertures are typically very small, providing a field of view of less than 2 millimeters. Observing and locating even smaller fluid inclusions through such a small aperture is extremely difficult. Furthermore, most existing laser ablation equipment moves the sample by moving the entire ablation cell, making precise sample movement within the cell impossible. This hinders efficient location and ablation of specific fluid inclusions. Additionally, traditional equipment can only analyze inclusions in a small sample at a time. Frequent opening of the ablation cell is required to change samples, reducing analytical efficiency, affecting the stability of the mass spectrometer, and ultimately impacting the accuracy of the analytical results. Summary of the Invention

[0004] In view of this, the present invention provides a cryo-laser ablation cell for reflected light fluid inclusions, which can solve the problems of freezing and locating inclusions in the process of compositional analysis of fluid inclusions by laser ablation.

[0005] This invention provides a cryo-laser ablation chamber for reflective fluid inclusions. The device mainly consists of a shell, a freezing chamber, an ablation chamber, and a top cover. The freezing chamber, located at the bottom of the shell, is made of pure silver and uses liquid nitrogen as the cooling medium. The top of the chamber is mirror-polished and connected to a liquid nitrogen tank and pump via a Teflon hose. The ablation chamber is mounted above the freezing chamber and has a standard sample mounting hole. The chamber is spindle-shaped and has inlet and outlet ports at both ends, connected to a carrier gas pipeline. The top cover is fitted with a calcium fluoride glass viewing window, allowing 193nm laser light to pass through. This invention uses pure silver with high thermal conductivity and high reflectivity to make the freezing chamber, ensuring the required cooling and reflective effects. In use, the downward-facing light emitted from the microscope passes through a thin slice of the inclusion sample and is reflected by the polished mirror surface of the top of the freezing chamber. The reflected light is then transmitted back through the sample and returns to the microscope, thus enabling precise observation and positioning of the fluid inclusions without relying on conventional downward-facing transmission light systems.

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

[0007] A cryo-laser ablation cell for reflective optical fluid inclusions includes an outer shell, a freezing chamber, an ablation chamber, and a top cover;

[0008] The outer shell consists of a semi-cylindrical shell and a square base plate; the cylindrical shell has a liquid nitrogen inlet, a liquid nitrogen outlet, a carrier gas inlet pipe and a carrier gas outlet pipe on its side, and the square base plate is located at the bottom of the semi-cylindrical shell and has mounting holes.

[0009] The top side of the outer shell is provided with sealing bolt holes for sealing connection with the top cover, and the top edge of the semi-cylindrical shell is provided with an annular fluororubber sealing ring.

[0010] The freezing chamber is a hollow, flat cylindrical cavity made of pure silver, with a mirror-polished top. The interior of the freezing chamber features a spiral, meandering channel, with its inlet and outlet connected to liquid nitrogen inlet and outlet pipes on the side of the freezing chamber, respectively. The liquid nitrogen inlet and outlet pipes are connected to a liquid nitrogen tank and a liquid nitrogen pump, respectively.

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

[0012] The ablation chamber is installed inside the outer shell. The center of the ablation chamber has a circular hole with the same diameter as the freezing chamber. The freezing chamber is nested inside the ablation chamber. After assembly, the bottom surface of the ablation chamber is flush with the top mirror surface of the freezing chamber. The ablation chamber is spindle-shaped. There are air inlets and outlets at both ends of the ablation chamber, which are connected to the air inlet pipe and air outlet pipe of the outer shell, respectively. The ablation chamber has a standard sample mounting hole on the side near the air outlet.

[0013] The top cover is a hollow ring with a calcium fluoride glass window installed inside to ensure the transmission of a 193nm laser. Densely arranged small exhaust holes are located above the calcium fluoride glass window on the inner side of the ring. These holes connect to a hollow pipe inside the ring, which runs from an inlet pipe to a liquid nitrogen pump exhaust pipe. During use, dry exhaust gas is discharged through the exhaust holes and blows across the surface of the calcium fluoride glass window to prevent fogging and frost.

[0014] Compared with existing technologies, this invention has the following advantages: The cryo-cavity does not rely on traditional downward-facing transmitted light systems. Through a top mirror-polished design, it converts the downward-facing light emitted by a reflected light microscope into upward-facing transmitted light, thus achieving the same observation effect as a traditional transmitted light microscope. The cryo-cavity design without a light-perforation aperture not only provides an ultra-large observation field of view but also ensures excellent freezing performance. This design breaks the limitation of the field of view size in traditional cryo-cavity devices with light-perforation apertures, making sample observation and movement more free and convenient. Furthermore, samples can be placed on the entire top of the cryo-cavity, allowing for the simultaneous testing of multiple small or ultra-large samples. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0016] Figure 2 This is a schematic diagram of the freezing chamber structure of the present invention. Detailed Implementation

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

[0018] Liquid nitrogen pump reference Figure 1 A cryo-laser ablation cell for reflective optical fluid inclusions includes an outer shell 1, a freezing chamber 2, an ablation chamber 3, and a top cover 4;

[0019] The outer shell 1 is the main structure of the erosion tank, consisting of a semi-cylindrical shell 18 and a square base plate 19. The cylindrical shell 18 has a liquid nitrogen inlet 5, a liquid nitrogen outlet 6, a carrier gas inlet pipe 14, and a carrier gas outlet pipe 15 on its side. The square base plate 19 is located at the bottom of the semi-cylindrical shell 18 and has four mounting holes 20 for fixing the device. The carrier gas inlet pipe 14 has an outer diameter of 4.5 mm and an inner diameter of 0.8 mm, and the carrier gas outlet pipe 15 has an outer diameter of 4.5 mm and an inner diameter of 3 mm to ensure good rinsing effect. The top side of the outer shell 1 has sealing bolt holes 21, and the top edge of the semi-cylindrical shell 18 has an annular fluororubber sealing ring 22.

[0020] refer to Figure 1 and Figure 2The freezing chamber 2 is a hollow, flat cylindrical cavity with a diameter of 20mm, a thickness of 5mm, and a wall thickness of 1mm. The freezing chamber 2 is made of pure silver, with a mirror-polished top. The interior of the freezing chamber 2 is designed with a spiral, meandering channel to improve heat exchange and cooling efficiency. The inlet and outlet of the channel are respectively connected to a liquid nitrogen inlet pipe 9 and a 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 connected to a liquid nitrogen tank and a liquid nitrogen pump, respectively.

[0021] refer to Figure 1 and Figure 2 A temperature probe 11 is installed inside the freezing chamber 2 and connected to an external temperature controller.

[0022] refer to Figure 1 The ablation chamber 3 is installed inside the outer shell 1. The ablation chamber 3 has a circular hole with the same diameter as the freezing chamber 2 at its center. The freezing chamber 2 is nested 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. The two ends of the cavity of the ablation chamber 3 have a carrier gas inlet 12 and a carrier gas outlet 13, which are respectively connected to the carrier gas inlet pipe 14 and the carrier gas outlet pipe 15 of the outer shell 1. The ablation chamber 3 has a standard sample mounting hole 16 on the side near the inlet 12.

[0023] refer to Figure 1 The top cover 4 is a hollow ring, inside which a calcium fluoride glass window 17 is installed to ensure the transmission of 193nm laser light. Densely arranged exhaust holes 18 are provided above the calcium fluoride glass window 17 on the inner side of the ring. The exhaust holes 18 are connected to a hollow pipe inside the ring, which runs from an air inlet pipe 19 to a liquid nitrogen pump exhaust pipe. During use, dry exhaust gas is discharged through the exhaust holes 18 and blows across the surface of the calcium fluoride glass window 17 to prevent fogging and frost.

[0024] refer to Figure 1 The outer cross section of the top cover 4 is wedge-shaped so that the housing can be sealed by tightening the locking bolts.

[0025] refer to Figure 1 The outer shell 1, the erosion cavity 3, and the top cover 4 of the device are all made by 3D printing technology to ensure the precision machining of the complex internal structure.

[0026] refer to Figure 1 The specific implementation steps are as follows:

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

[0028] 2. Place the sample slice containing the inclusion to be tested and the fluid inclusion standard on the mirror surface of the freezing chamber 2 in the middle of the ablation chamber 3, and insert the solid standard target into the standard mounting hole 16, cover the top cover 4, and tighten the locking bolt.

[0029] 3. After sealing the erosion chamber, purge the residual air inside the erosion chamber with carrier gas to prevent the sample from frosting during the subsequent freezing process;

[0030] 4. After purging, turn on the microscope's reflected light system to locate the inclusions to be tested;

[0031] 5. After the package to be tested 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 a temperature controller and microscope;

[0032] 6. Once the sample is frozen, laser ablation analysis can begin.

Claims

1. A reflective optical fluid-encased cryogenic laser ablation cell, characterized by, It comprises a shell (1), a freezing cavity (2), an ablation cavity (3) and a top cover (4); The shell (1) is provided with liquid nitrogen inlet holes (5), liquid nitrogen outlet holes (6), carrier gas inlet pipes (7) and carrier gas outlet pipes (8) on the side surface; The top of the shell (1) is sealingly connected with the top cover (4); The top of the freezing cavity (2) is polished by a mirror surface; the inside of the freezing cavity (2) is designed as a spiral winding channel, the inlet and outlet of the channel are respectively connected with liquid nitrogen inlet pipes (9) and liquid nitrogen outlet pipes (10) on the side surface of the freezing cavity (2); the liquid nitrogen inlet pipes (9) and the liquid nitrogen outlet pipes (10) pass through the liquid nitrogen inlet holes (5) and the liquid nitrogen outlet holes (6) on the side surface of the shell (1) and are respectively connected with a liquid nitrogen tank and a liquid nitrogen pump; A temperature measuring probe (11) is installed in the freezing cavity (2) and is connected with an external temperature control table; The ablation cavity (3) is installed in the shell (1); the ablation cavity (3) is provided with a circular hole with the same diameter as the freezing cavity (2) in the center; the freezing cavity (2) is nested in the ablation cavity (3); the bottom surface of the ablation cavity (3) is flush with the top mirror surface of the freezing cavity (2) after assembly; the ablation cavity (3) is provided with carrier gas inlet holes (12) and outlet holes (13) at both ends of the cavity and is connected with carrier gas inlet pipes (14) and outlet pipes (15) of the shell (1); the ablation cavity (3) is provided with a sample mounting hole (16) on the side close to the inlet hole (12); The top cover (4) is a hollow circular ring; a calcium fluoride glass window (17) is installed in the inside of the circular ring; a plurality of exhaust small holes (18) are densely arranged above the calcium fluoride glass window (17) on the inner side of the circular ring; the exhaust small holes (18) are connected with a hollow pipeline in the circular ring; the hollow pipeline is connected from the inlet pipe (19) to the exhaust pipeline of the liquid nitrogen pump; during use, dry exhaust 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.

2. A reflective optical fluid enclosure laser ablation cell according to claim 1 wherein, The shell (1) comprises a semi-cylindrical shell (18) and a square bottom plate (19); the semi-cylindrical shell (18) is provided with liquid nitrogen inlet holes (5), liquid nitrogen outlet holes (6), carrier gas inlet pipes (14) and carrier gas outlet pipes (15) on the side surface; the square bottom plate (19) is located at the bottom of the semi-cylindrical shell (18) and is provided with mounting holes (20). The top side surface of the shell (1) is provided with sealing bolt holes (21) for sealingly connecting with the top cover (4); the top edge of the semi-cylindrical shell (7) is provided with an annular fluorine rubber sealing ring (22).

3. A reflective optical fluid enclosure laser ablation cell according to claim 1 wherein, The freezing cavity (2) is a hollow flat cylindrical cavity; the freezing cavity (2) is made of pure silver.

4. A reflective optical fluid enclosure laser ablation cell according to claim 1 wherein, The cavity of the ablation cavity (3) is spindle-shaped.

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