Laser ablation cell

Abstract

To suppress convection within the cell and improve the flow velocity of a carrier gas.SOLUTION: The laser ablation cell includes: a cell body 2; a port block 3A connected to an introduction side of a carrier gas of the cell body; a port block 3B connected to a discharge side of the carrier gas of the cell body; and a slit member 13 interposed at a connection end between the cell body 2 and the port block 3A. The slit member 13 controls the amount of a carrier gas to introduce to the cell body 2 by shutting off a part of the introduction port of the port block 3A.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cell for laser ablation. [Background technology]

[0002] In conventional elemental analysis using laser ablation (so-called LA-ICP-MS), the surface of the object to be measured is irradiated with a laser to turn the object into an aerosol (particles).The aerosol (particles) are then introduced into an analytical device such as an ICP-MS or ICP-OES for elemental analysis.

[0003] The inlet of analytical equipment such as ICP-MS and ICP-OES generates plasma in a gas atmosphere. Therefore, in order to irradiate the target with a laser and transport the aerosol (particles) directly to the analytical equipment, a cell is required to create a gas atmosphere on the irradiated surface. In addition, to transport the aerosol, gas flows from the cell inlet through the outlet to the analytical equipment.

[0004] In this case, the upper limit of the gas flow rate is limited by the analytical instrument, preventing a sufficient increase in the flow rate within the cell. This can lead to gas convection around the sample, potentially affecting accuracy depending on the location of the object being measured. For example, Figure 10 shows the vertical convection in a conventional cell, and Figure 11 shows the depthwise convection in a conventional cell. In the cell 100 shown in Figures 10 and 11, port blocks 101A and 101B are connected to the inlet and outlet sides of the cell body 102, respectively. The top surface of the cell body 102 is open, and the window 106 is secured by a cover member 105. A sample stage 103 is placed in the recess 102A of the cell body 102, and a sample 104 to be measured is placed on top of it. Carrier gas introduced through the inlet channel 101A-1 in the port block 101A is introduced into the cell body 2, and the aerosol is discharged via the outlet channel 101B-1. The discharged carrier gas convects in the vertical direction as indicated by reference symbol T1 in FIG. 10, and convects in the depth direction as indicated by reference symbols T2 and T3 in FIG.

[0005] When performing two-dimensional or three-dimensional distribution (imaging) analysis, the flow rate within the cell cannot be increased, so in order to increase spatial resolution, it is necessary to leave a sufficient amount of time between laser irradiation of adjacent locations, which has the disadvantage of taking a long time to measure (if the interval is too short, the aerosol will mix with the aerosol from the previous stage).

[0006] For example, Figure 10 also shows the flow of aerosols when performing two-dimensional or three-dimensional distribution analysis. In the figure, when a point on the left side is irradiated with a laser, the aerosol flows into the analyzer (symbol U1). The aerosol flows into this analyzer, and when the analysis is complete, the laser is irradiated at an adjacent point, and the aerosol then flows into the analyzer (symbol U2). By repeating this process, the distribution status can be analyzed. For this reason, in order to further improve spatial resolution and shorten measurement time, conventional technology has devised ways to increase the flow rate within the cell, such as by using a separate cell with a small internal volume.

[0007] Here, Patent Document 1 discloses a laser ablation mass spectrometer that includes a sample stage, a laser irradiation unit, an airflow transport system, an ion source, and an analysis unit. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-191134 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the prior art such as Patent Document 1, it was not possible to control the convection within the cell or the flow rate of the carrier gas within the cell on the cell side.

[0010] The present invention has been made in view of the above problems, and an object of the present invention is to suppress convection within a cell and improve the flow rate of the carrier gas. [Means for solving the problem]

[0011] In order to solve the above problem, a laser ablation cell according to one embodiment of the present invention comprises a cell body, an inlet part connected to the carrier gas inlet side of the cell body, an outlet part connected to the carrier gas outlet side of the cell body, and a slit member interposed between the connection end of the cell body and the inlet part, and the slit member controls the amount of carrier gas introduced into the cell body by blocking a portion of the inlet port of the inlet part.

[0012] A laser ablation cell according to another aspect of the present invention comprises a cell body, an inlet portion connected to the carrier gas inlet side of the cell body, an outlet portion connected to the carrier gas outlet side of the cell body, and an inner member inserted into the cell body in a position parallel to the bottom surface, and the inner member controls the flow rate of the carrier gas inside the cell body by regulating the size of the carrier gas filling space inside the cell body. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a technique for suppressing convection within a cell and improving the flow rate of a carrier gas. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing the configuration of a cell for laser ablation according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating a method for placing an object to be measured in the cell for laser ablation. [Figure 3] FIG. 3 is a configuration diagram showing the installation state and operating direction of the slit member in the laser ablation cell. [Figure 4]FIG. 4 is a diagram showing the gas flow around the slit member in the same cell for laser ablation. [Figure 5] 5(a) and 5(b) are configuration diagrams showing the operating state of the slit member in the cell for laser ablation. [Figure 6] 6(a) and 6(b) are diagrams showing an improved example of the slit member in the cell for laser ablation. [Figure 7] FIG. 7 is a diagram showing the configuration of a cell for laser ablation according to the second embodiment of the present invention. [Figure 8] FIG. 8 is a partial cross-sectional view of the cell for laser ablation. [Figure 9] 9(a), 9(b), and 9(c) are diagrams showing the configuration of the inner member of the cell for laser ablation. [Figure 10] FIG. 10 is a diagram showing vertical convection of gas in a cell according to the prior art. [Figure 11] FIG. 11 is a diagram showing convection of gas in the depth direction in a cell according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] First Embodiment The cell for laser ablation according to the first embodiment of the present invention controls the gas path within the cell body by providing a variable or detachable slit member within the cell.

[0017] FIG. 1 is a perspective view showing the configuration of a cell for laser ablation according to a first embodiment of the present invention, and FIG. 2 is a perspective view showing the state in which the installation block of the cell is pulled out, and will be described.

[0018] As shown in Figures 1 and 2, the laser ablation cell 1 is configured by attaching a port block 3A as an inlet portion to the carrier gas inlet side of the cell body 2, a port block 3B as an outlet portion to the outlet side, and a detachable installation block 7 to the cell body 2. In this example, bolts 12 are used to attach the port blocks 3A and 3B to the cell body 2. The cell body 2 is hollow and has an opening on its top surface, with a window 4 installed in the opening by a cover member 5. In this example, bolts 11 are used to install the window 4 by the cover member 5.

[0019] A carrier tube 9A is connected to the port block 3A on the carrier gas inlet side via a valve 8A, and a carrier tube 9B is connected to the port block 3B on the outlet side via a valve 8B. The end of the carrier tube 9B opposite to the end connected to the port block 3B is connected to an inlet (plasma ion source) 50 of the ICP-MS (OES).

[0020] Here, laser light from a laser light source (not shown) is irradiated onto the sample 11 in the cell body 2 from the direction indicated by symbol D3 in the figure, carrier gas is introduced from the direction indicated by symbol D1 in the figure, and aerosol is discharged in the direction indicated by symbol D2 in the figure.

[0021] As shown in FIG. 2, the mounting block 7 is attached to the cell body 2 by inserting it into the cell body 2 from the opening 2A in the depth direction (Z-axis direction). Locking members 6A and 6B, operated by handles 6C, are provided on the mounting block flat surface 7A of the mounting block 7. Operating the handles 6C opens and closes the locks of the locking members 3A-2 and 3B-2 provided on the port blocks 3A and 3B. Specifically, by inserting the mounting block 7 through the opening 2A of the cell body 2 and operating the handles 6C, the locking members 6A and 6B engage with the locking members 3A-2 and 3B-2, fixing the block in place. A mounting table 10 is attached to the recess 7C of the mounting block 7, and a sample 11 to be measured is placed on the top flat surface of the mounting table 10.

[0022] 3, 4, 5(a) and 5(b) show and explain the installation state and operating direction of the slit in the cell for laser ablation.

[0023] As shown in Figure 3, the carrier gas introduced through the inlet passage 3A-1 of the port block 3A is introduced into the inside of the cell body 2, but in the laser ablation cell 1 of this embodiment, a slit 13 is interposed at the connection end between the cell body 2 and the port block 3A to control the flow of the carrier gas introduced into the inside of the cell body 2.

[0024] More specifically, in this example, slit 13 is fixed in position on the flat surface of the connecting end of port block 3A with bolts 14A-14C, and the holes on slit 13 into which the bolts are inserted are elongated holes with a width in the height direction (Y-axis direction). Therefore, by adjusting the tightening position of the bolts, the opening area of ​​the outlet at the connecting end of inlet channel 3A-1 of port block 3A can be adjusted in the height direction by slit 13. In this way, by moving slit 13 in the height direction, it is possible to control the up and down airflow of the carrier gas within cell body 2. For example, in the state shown in Figure 4, the carrier gas flows downward from inlet channel 3A-1 as it passes through the slit, and is directed toward the surface of sample 11, the object of measurement.

[0025] 5(a) shows the slit 13 raised to its upper limit and fixed in position, and FIG. 5(b) shows the slit 13 lowered to its lower limit and fixed in position. In this example, the slit 13 has three vertically elongated holes 13A, 13B, and 13C arranged at equal intervals in the depth direction, and these holes are fixed in position to the flat surface of the connecting end of the port block 3A by bolts 14A, 14B, and 14C, respectively.

[0026] In this configuration, a sample 11 to be measured is placed on the mounting table 10 installed on the mounting block 7. With the mounting block 7 housed in the cell body 2, the handle 6C is operated to engage and lock the locking members 6A and 6B with the locking members 3A-2 and 3B-2. Then, carrier gas is introduced into the cell body 2 through the inlet channel 3A-1 of the port block 3A. Since a slit 13 is interposed between the port block 3A and the cell body 2, the width (opening area) of the inlet is regulated (controlled). As a result, the carrier gas becomes a downward current as it passes through the slit and is directed toward the surface of the sample 11 to be measured. Then, laser light from a laser light source (not shown) is irradiated through the window 4 toward the sample 11 to be measured. The aerosol (particles) are transported to the inlet of the ICP-MS via the outlet channel 3B-1 of the port block 3B, the valve 8B, and the transport tube 9B.

[0027] In the elemental analysis method by laser ablation using the laser ablation cell 1 according to an embodiment of the present invention, it is possible to selectively analyze only the areas irradiated with the laser, and mainly quantitative analysis and two-dimensional or three-dimensional distribution analysis are possible.

[0028] Here, the configuration of an improved example of the slit in the cell for laser ablation is shown and explained in Figs. 6(a) and 6(b).

[0029] 6(a), a plurality of holes 20A are provided above the slit 20 at non-equidistant intervals in the depth direction of the cell body 2 (longitudinal direction of the slit 20), and holes 20B, 20C, and 20D are provided below the hole 20A for fixing the position with bolts. In this way, by replacing the slit 20 with one having a plurality of holes 20A at non-equidistant intervals in the depth direction of the cell body 2, it becomes possible to control the amount of gas ejected in the depth direction.

[0030] 6(b), the slit 21 has an elongated hole 21A extending in the depth direction of the cell body 2 (the longitudinal direction of the slit 21), and holes 21B, 21C, and 21D are provided below the hole 21A for fixing the position with bolts. In this way, by replacing the slit 21 with one having an elongated hole 21A in the depth direction of the cell body 2, it is possible to limit the depth and the upper limit of the airflow.

[0031] According to the laser ablation cell of the first embodiment of the present invention, by interposing a slit member between the cell body and the inlet side port block, it is possible to control the gas path within the cell body by regulating the size of the outlet of the port block.

[0032] Second Embodiment The laser ablation cell according to the second embodiment of the present invention controls the gas flow rate within the cell body by providing a detachable inner member within the cell.

[0033] FIG. 7 is a perspective view showing the configuration of a cell for laser ablation according to a second embodiment of the present invention, and FIG. 8 is a partial cross-sectional view of the same cell, which will be described.

[0034] As shown in these figures, in the cell for laser ablation 31 according to the second embodiment, the port block 33B on the side surface of the cell body 2 can be removed, and the inner member 40 can be inserted or removed.

[0035] 7 and 8, the laser ablation cell 31 is configured by attaching port blocks 33A and 33B to the sides of the carrier gas inlet and outlet of the cell body 32, respectively, and further attaching a removable mounting block 37 to the cell body 32. The cell body 32 is hollow and has an opening on its top surface, with a window 34 installed over the opening using a cover member 35. A carrier tube is connected to the port block 33A on the carrier gas inlet side via a valve 38A, and a carrier tube is connected to the port block 33B on the outlet side via a valve 38B. Laser light from a laser light source (not shown) is irradiated onto the sample through the window 34 in the vertical direction of the cell body 32, from top to bottom.

[0036] When the port block 33B is removed from the cell body 32, an opening 32A is exposed on the flat surface of the cell body 2. By inserting the inner member 40 into this opening 32A and reattaching the port block 33B to the cell body 2, the space in the cell body 2 where the sample 11 is placed (the space filled with the carrier gas) is restricted and narrowed, making it possible to improve the gas flow rate.

[0037] The structure of the inner member of the cell for laser ablation is shown and explained in Figures 9(a), 9(b), and 9(c). Figure 9(a) is a left side view, Figure 9(b) is a plan view, and Figure 9(c) is a right side view.

[0038] As shown in these figures, the inner member 40 has a hole 40A for laser irradiation in the center, and an outlet path 40B is carved in the gas path direction centered on the hole 40A. The outlet path 40B is formed so that the inlet side of the hole 40A is wider and the outlet side is narrower than the inlet side. This prevents gas from filling unnecessary areas and makes it possible to increase the gas flow rate in the laser irradiation area.

[0039] According to the laser ablation cell of the second embodiment of the present invention, by inserting an inner member into the cell body, the space filled with the carrier gas can be narrowed, thereby making it possible to control the gas flow rate within the cell body.

[0040] As described above, according to an embodiment of the present invention, first, a laser ablation cell is provided which comprises a cell body 2, a port block 3A as an inlet part connected to the carrier gas inlet side of the cell body 2, a port block 3B as an outlet part connected to the carrier gas outlet side of the cell body 2, and a slit member 13 interposed between the connection end of the cell body 2 and the port block 3A as an inlet part, and the slit member 13 controls the amount of carrier gas introduced into the cell body 2 by blocking a portion of the inlet port of the port block 3A as an inlet part.

[0041] Here, the slit member 13 is attached to the port block 3A side as the introduction part using, for example, a bolt, and the size of the shielding can be adjusted by adjusting the attachment position on the port block 3A as the introduction part in the vertical direction.

[0042] Alternatively, the slit member 20 may be a slit section 20 in which a plurality of holes 20A are formed in the longitudinal direction, or a slit section 21 in which one elongated hole 21A is formed.

[0043] In addition, the cell body 2 may further include an inner member 40 that is inserted into the cell body 2 in a position parallel to the bottom surface, and the inner member 40 may control the flow rate of the carrier gas inside the cell body 2 by regulating the size of the carrier gas filling space inside the cell body 2 in the vertical direction.

[0044] Secondly, a laser ablation cell is provided which comprises a cell body 32, a port block 33A as an inlet part connected to the carrier gas inlet side of the cell body 32, a port block 33B as an outlet part connected to the carrier gas outlet side of the cell body 32, and an inner member 40 inserted into the cell body 2 in a position parallel to the bottom surface, wherein the inner member 40 regulates the size of the carrier gas filling space inside the cell body 32 in the vertical direction, thereby controlling the flow rate of the carrier gas inside the cell body 32.

[0045] Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these and that various improvements and modifications can be made without departing from the spirit and scope of the present invention.

[0046] For example, the number and shape of the holes of the slits described above are not limited to those described above and can be designed according to the application and measurement conditions. The shape and installation position (height) of the outlet path of the inner member can also be designed according to the application and measurement conditions. Furthermore, it is possible to combine the first and second embodiments to create an ablation cell equipped with both a slit member and an inner member. [Explanation of symbols]

[0047] 1...Laser ablation cell, 2...Cell body, 3A, 3B...Port block, 3A-1...Inlet path, 3A-2...Locking member, 3B-1...Outlet path, 3B-2...Locking member, 4...Window portion, 5...Cover member, 6...Handle portion, 6A, 6B, 6C...Locking member, 7...Installation block, 7A...Installation block flat portion, 7B...Installation block body, 7C...Recess, 8A, 8B...Valve, 9A, 9B...Transport tube, 10...Installation table, 11...Sample, 11, 12...Screw member, 13...Slit member, 13A, 13B, 13C...Elongated hole portion, 14...Bolt, 14A, 14B, 14C...Bolt, 20 ...slit, 20A...hole, 20B, 20C, 20D...hole, 21...slit, 21A...long hole, 21B, 21C, 21D...hole, 31...laser ablation cell, 32...cell body, 32A...opening, 33A, 33B...port block, 33A-2, 33B-2...locking member, 34...window, 35...cover member, 36...handle portion, 36A, 36B...locking member, 36C...handle portion, 37...mounting block, 37A...recess, 38A, 38B...valve, 40...inner member, 40A...hole, 40B...outlet path, 50...ICP-MS inlet (plasma ion source).

Claims

1. A cell body; an inlet connected to the carrier gas inlet side of the cell body; an outlet portion connected to the carrier gas outlet side of the cell body; a slit member interposed between the cell body and the connection end of the introduction portion, The slit member controls the amount of the carrier gas introduced into the cell body by blocking a part of the inlet of the introduction part. Laser ablation cell.

2. The slit member is attached to the introduction section side, and the size of the shielding is adjusted by adjusting the attachment position to the introduction section in the height direction.

2. The cell for laser ablation according to claim 1.

3. The slit member has a plurality of holes or one long hole formed in the longitudinal direction.

2. The cell for laser ablation according to claim 1.

4. The cell body further includes an inner member inserted into the cell body in a positional relationship parallel to the bottom surface, and the inner member controls the flow rate of the carrier gas inside the cell body by regulating the size of the filling space for the carrier gas inside the cell body. The cell for laser ablation according to any one of claims 1 to 3.

5. A cell body; an inlet connected to the carrier gas inlet side of the cell body; an outlet portion connected to the carrier gas outlet side of the cell body; an inner member inserted into the cell body in a positional relationship parallel to the bottom surface; Equipped with The inner member controls the flow rate of the carrier gas inside the cell body by restricting the size of the space filled with the carrier gas inside the cell body. Laser ablation cell.

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