JP2002243644A - Inductively coupled plasma emission spectrochemical analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductively coupled plasma emission spectrochemical analyzer having a photometric height adjusting means that has a simple structure, is low cost, and is superior in operability. SOLUTION: An optical emission system is constituted only of one lens, and at the same time, the photometric height of the system is adjusted by vertically turning the system around a fulcrum, provided in the vicinity of an incident slit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductively coupled plasma emission spectrometer having an incident optical system. It relates to a mechanism for height adjustment.

[0002]

2. Description of the Related Art An inductively coupled plasma emission spectrometer is as follows. The sample to be measured is introduced into the high frequency induction plasma. The light of this plasma is guided into the spectroscope via the incident optical system. The spectroscope splits the incident light into spectral light of each wavelength and extracts a specific spectral light. The spectral light extracted by the spectrometer is guided to a photodetector and detected, whereby qualitative / quantitative analysis of elements contained in the sample is performed.

[0003] The incident optical system forms an image of the plasma on the entrance slit, which is the entrance of the spectroscope. When forming an image, which portion of the plasma is formed on the entrance slit affects the sensitivity and stability of the analysis. this is,
It depends on the distribution characteristics of light in the plasma.

[0004] The plasma has a donut structure. Near the center of the plasma, light used for analysis caused by an analysis element in the sample is distributed, and in a portion off the center, light of a background component that hinders analysis is distributed.

[0005] For this reason, when analyzing with high sensitivity, it is important to determine which part of the plasma to observe.

When observing the plasma from the axial direction,
Observe the center.

When observing the plasma from the radial direction,
In the left-right direction (radial direction of the plasma), the center is preferably approximately. However, the vertical direction (the axial direction of the plasma) is slightly different depending on the attributes of the sample, the elements to be measured, the measurement conditions, and the like, and thus adjustment is required.

The vertical position is called a photometric height.
Generally, an adjustment mechanism is provided for the photometric height. The following are conventional mechanisms for adjusting the photometric height. 1. What raises and lowers the position of the plasma itself. 2. This system adjusts the photometric height by changing the inclination of the reflecting surface by using a reflecting optical system as the incident optical system provided between the plasma and the spectroscope while keeping the position of the plasma and the spectroscope as they are. 3. Adjusts the photometric height by moving only the lens in the incident optical system up and down in parallel.

[0009]

However, these photometric height adjusting mechanisms have the following problems.

[0010] 1. What raises and lowers the position of the plasma itself. Since the entire plasma generator is large, the up-and-down mechanism is large and expensive, and maintenance is also difficult.

2. This system adjusts the photometric height by changing the inclination of the reflecting surface by using a reflecting optical system as the incident optical system provided between the plasma and the spectroscope while keeping the position of the plasma and the spectroscope as they are. At least two reflective surfaces are required, which is expensive. In addition, the reflection surface may be deteriorated by strong light from the plasma, which may cause a problem in durability.

3. Adjusts the photometric height by moving only the lens in the incident optical system up and down in parallel.

This has the following advantages over the above two.

1. Since the lens is moved up and down without moving the plasma up and down, the moving mechanism is simplified.

2. Since the reflection surface is not used, the cost is low and the reflection surface does not deteriorate. On the other hand, the inside of the incident optical system is purged with gas. The drive section including the lens must maintain the airtightness at the boundary with the incident optical system. For this reason, this method has the following problems. -The structure for realizing the parallel movement, airtight structure, and mounting / removing mechanism for lens cleaning is complicated and expensive.・ Also, the operability is poor.・ ・ Since the parallel movement is performed while maintaining airtightness, the seal parts on the boundary surface are severely worn.

[0016]

An incident optical system is constituted by a single lens, and the height of the photometry is adjusted by rotating the incident optical system up and down around a position near an entrance slit as a fulcrum.

[0017]

The principle of changing the photometric height is the same as that of the mechanism for moving the lens in parallel. By rotating the incident optical system itself up and down, the principal ray of the lens in the incident optical system changes, and the photometric position of the plasma changes. Since the distance from the entrance slit to the lens is sufficiently large compared to the rotation angle, the rotational movement of the present invention can be approximated to a parallel movement. The lens used has a size obtained by adding the amount of movement to the size of the light beam. The advantages of the present invention are as follows.

1. Since the incident optical system itself is simply rotated without raising and lowering the plasma, the moving mechanism is simplified.

2. Since the reflection surface is not used, the cost is low and the reflection surface does not deteriorate.

3. Since the incident optical system itself is moved, the lens unit may be fixed, and there is no gas leakage due to wear of the sealing parts.

4. Since the airtight structure and the attachment / detachment mechanism for cleaning the lens can be configured separately, operability can be improved.

On the other hand, when the center light beam deviates from the center of the lens, the aberration increases and the image of the plasma is distorted. However, since the image of the plasma is sufficiently large as compared with the entrance slit, the influence on the analysis such as a decrease in intensity or sensitivity is negligibly small.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, details will be described based on embodiments.

FIG. 1 shows an embodiment of the present invention.

Plasma 1. And spectrometer6. Is fixed. Only the incident optical system 2. including the lens 3. in the meantime is rotated up and down by the rotating mechanism 4. By rotating up and down, the principal ray of the lens 3 changes, and the plasma 1.
Change the photometric position of Lens 3. is approximately 50-
It has a size of about 100 mm and requires only a simple moving mechanism.

FIGS. 2 and 3 show an embodiment of the present invention.

The basic operation principle is the same as in FIG. It is also possible to change the position of the rotation mechanism 4 to move the incident optical system.

FIG. 4 shows a second embodiment of the present invention.

A rotating shaft is provided at the end of the incident optical system 2 on the side of the spectroscope 6.
Step 7 is provided. The rotating shaft 7. is mounted at a position where the incident optical system 2. can be rotated vertically. A direct-acting drive mechanism to rotate the incident optical system up and down with the rotation axis 7.
Use 8. The direct-acting drive mechanism 8. is provided below the position where the rotary shaft 7. is installed, and is installed perpendicularly to the surface of the incident optical system 2. with respect to the spectroscope 6. When the drive unit of the direct drive mechanism 8. moves back and forth, it pushes the contact surface with the incident optical system 2.
The pressed incident optical system 2. is rotated up and down on the rotation axis 7. as a fulcrum according to the principle of leverage. FIG. 5 shows a conventional example.

The incident optical system 2 and the spectroscope 6 are fixed, and the plasma 1. is moved up and down by a vertical movement mechanism 9. The generator (not shown) for plasma 1. is approximately 20K
g, 30 cm cubic. The mechanism 9. for raising and lowering the generator is large, complex, expensive and prone to failure.

FIG. 6 shows a conventional embodiment.

Plasma 1. And spectrometer6. And fix the incident optical system 2 to the concave mirror. And plane mirror12. And concave mirror rotation mechanism 1
10. Concave mirror 10. By concave mirror rotation mechanism 11. Concave mirror 10. Is changed. In the plane mirror 12., the reflection surface is deteriorated, so that a problem easily occurs in durability.

FIG. 7 shows a conventional embodiment.

Plasma 1. And spectrometer6. Is fixed. 2. Lens between them Only the parallel movement moves up and down by the parallel movement mechanism 13. By moving up and down, the lens 2.
Of the plasma changes. Change the photometric position of The principle of changing the photometric height is the same as in the present invention. However, the translation mechanism 13. Must move in parallel while maintaining the airtightness of the boundary between the drive unit 14. including the lens and the incident optical system, and there is a problem of durability.

[0035]

According to the present invention, it is possible to use a simple moving mechanism and not use a reflecting surface. As a result, it is possible to obtain a simpler and less troublesome adjusting mechanism of the photometric height.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.

FIG. 2 shows an embodiment of the present invention.

FIG. 3 shows an embodiment of the present invention.

FIG. 4 shows an embodiment according to claim 2;

FIG. 5 is a conventional example.

FIG. 6 shows a conventional example.

FIG. 7 shows a conventional example.

[Explanation of symbols]

 1. Plasma 2. Incident optical system 3. Lens 4. Rotating mechanism 5. Incident slit 6. Spectroscope 7. Rotating axis 8. Amplitude drive mechanism 9. Vertical movement mechanism 10. Concave mirror 11.Concave mirror rotation mechanism 12.Plane mirror 13.Parallel movement mechanism 14.Drive unit

Claims (2)

[Claims] An inductively-coupled plasma; a spectroscope; an entrance slit formed in the spectroscope; a lens for imaging light from the inductively-coupled plasma onto the entrance slit; An inductively coupled plasma emission spectroscopy analyzer comprising: an inductively coupled plasma emission spectroscopy analyzer, wherein the moving mechanism is a rotation mechanism having a rotation center near the entrance slit. 2. The inductively coupled plasma emission spectrometer according to claim 1, wherein the rotation mechanism of the incident optical system includes a rotation shaft and a direct drive mechanism.