JPS60121664A - Mass spectrometer - Google Patents

Abstract

PURPOSE:To simplify the optical system of an ion source by arranging an optical fiber flux facing a sample in an ionization chamber while making it possible to connect its other end to both a laser light source and an observation means for observing the surface of a sample. CONSTITUTION:An ionization chamber 1 composed of an acceleration electrode 2 and a repeller 3 is provided inside a vacuum container 4 and a sample 5 is placed on a traveling stand 6 located inside while inserting an optical fiber flux 7 facing the sample 5. Further, the other end of the optical fiber flux 7 is enabled to be connected to a laser light source 8 and an observation means 9 as well to observe the surface of the sample 5 as occasion demands thus forming a mass spectrometer provided with a laser excitation type ion source. Accordingly, firstly the stand 6 is made to travel for setting the part of the sample 5 to be analyzed while observing the surface of the sample 5 followed by radiating laser light 11 while connecting it to the laser source 8 so as to simplify an optical system by making it to be used for both observation and irradiation in common.

Description

Detailed Description of the Invention (Field of Application in Industry-1-) The present invention relates to a mass spectrometer equipped with a laser-excited ion source.

(Conventional Edanami) Quality j1 separation is the separation of ions with different masses under an electric field and/or a magnetic field to determine the distribution of ion masses, and is used in chemical analysis and the like. The mass spectrometer is
An ion source for generating ions, a mass separation system for separating ions with different masses from the generated ions by appropriately using a magnetic field and/or an electric field, and a detection recording system for detecting and recording the separated ions. It consists of

There are various types of ion sources, and a laser-excited ion source generates ions by irradiating a sample with a laser beam. The excitation process is as follows. That is, when irradiated with laser light, the sample can simultaneously absorb multiple photons, obtain ionization energy, and generate ions. Ionization is thus possible without the need for vacuum ultraviolet light. Furthermore, if the intensity of the laser beam is sufficiently strong, a charging field strong enough to cause ionization will be generated. Furthermore, when a sufficiently strong laser beam is irradiated onto a sample and the irradiated portion is melted and vaporized, ionization can occur at the same time.

When a laser-excited ion source is used to ionize a solid sample, local analysis of only the area irradiated with the laser beam is possible, and by changing the intensity of the light beam, analysis in the depth direction is also possible.

By the way, in the analysis of such a solid sample, a means for observing the sample surface is essential. Conventionally, two optical systems, the surface viewing means and the laser irradiation optical system, were provided separately or in common. For example, surface observation is performed using an optical microscope or a scanning electron microscope. The laser irradiation optical system uses a laser light source such as a gas laser, and uses many mirrors and lenses, is large, has a long optical path, and is fixed. In this way, since two optical systems (Jf) are used, the equipment is quite expensive,
However, it had the disadvantage of being large and complicated.

(LI aspect of the invention) An object of the present invention is to combine an observation means and a laser irradiation optical system with
- To provide a mass spectrometer equipped with a standardized laser-excited ion source.

(Structure of the Invention) For this purpose, an ionization chamber is placed adjacent to a solid mass separation system using a laser-excited ion source, and an ionization chamber into which a solid sample can be taken; It includes a bundle of optical fibers that are placed near the sample and whose thin ends can be connected to both a laser light source and an observation device for observing the surface of the sample.

(Embodiment) The attached drawing A is a schematic diagram of an embodiment according to the present invention. The ionization chamber 1 is partitioned from an accelerating electrode 2 and a repeller 3, and is located in a vacuum container 4. A solid sample 5 is fixed on a stage 6 in the ionization chamber 1 . The stage 6 finishes by adjusting the position of the sample 5 using a moving mechanism (not shown). The optical fibers are fixed to each other inside a vacuum container,
They constitute a circular bundle 7 and are introduced into the ionization chamber 1 from outside the container in a known manner. One end of the optical fiber bundle 7 is fixed near the sample 5. This end face and the sample surface are arranged approximately parallel to each other. The other end of the bundle 7 is a laser light source 8 or an observation device for observing the surface! 3, arrange it so that it can be connected as necessary. This observation device 9 is, for example, an optical microscope.

Identified fiber in bundle 7 - laser ray 11
When the sample surface is irradiated, ions (usually positive ions) are locally generated from the irradiated portion 5r. f', l]i between the repeller 3 and the accelerating electrode 2, is it positive? 4iI47 is added, Repeller 3 repels the generated ions,
Ions pass through a slit 12 provided in the center of the accelerating electrode 2.
from the mass separation system. The shape of the repeller and the above voltage are determined to suit each individual device. Next, the ions are separated by a mass separation system, and the mass of the irradiated portion 41i is obtained.

On the outside of this slit 12, an extraction electrode 13, a half-plate 1, and an output electrode 15 are sequentially provided as in a normal double convergence type mass separation system, and in the center of these electrodes there is a A slit is provided to allow ions to pass through. A positive voltage is applied between the accelerating electrode 2 and the extraction electrode 12 so that the potential of the accelerating electrode 2 becomes, for example, 1() (har) higher, and the potential of the accelerating electrode 2 is applied to the bar 7 plate ↓. For example, a positive voltage of about 80% is applied, and the output electrode 15 is set at ground potential.
The ions passing through 2 are accelerated and pass through the exit slit 6, where an ion flow 17 is generated. Although not shown, the ion flow 17
is then passed through an electrostatic analyzer that generates a modal electric field, is energy focused, and then bent according to its mass in a uniform magnetic field.

When using this embodiment, first the optical fiber bundle 7 is connected to the observer 9. The surface of the sample 5 is illuminated I) by a lamp (not shown) provided in the space 1, but may also be illuminated through some optical fibers in the bundle 7. The position of the sample 5 is controlled by moving the table 6. Observer 9
Observe the surface of sample 5 using FIG. 2 is a perspective view showing this situation. The sample surface shown below is observed by the fiber bundle 7 shown above. In this way, the portion A to be analyzed is specified.

Next, a laser light source 8 is connected to one or more optical fibers a corresponding to portion A in the bundle 7 of optical fibers. Then, part A' (locally irradiates with jifi and ionizes.

As explained in 1-1 below, the optical fiber bundle 7 is used for observing the sample and for controlling the laser beam.
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Note that the cross section of the bundle 7 can be configured in any shape, such as a -dimensional arrangement, depending on the purpose.

Ionization can also be promoted by adding a 1.1 lens or by arranging a lens at the tip of part or all of the optical fiber. In this case, the position of the sample is adjusted so that the focal point of the lens is at the surface of the sample 5.

In this example, a double convergence type mass separation system was used, but any mass separation system such as a single convergence type or quadrupole type can be used. Ion sources can be used.

(Effects of the Invention) By emitting light near the sample A11 from the laser light source and the observation device, the optical system becomes compact and simple, and can be provided at a low price.

In addition, a bundle of optical fibers is easy to bend, and the laser light source and observation device can easily be placed in arbitrary positions.

By using a bundle of optical fibers, it is easy to observe the sample surface, identify the location to be analyzed, and mass analyze only this identified portion of the sample.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the invention. FIG. 2 is a perspective view showing how the sample is observed. DESCRIPTION OF SYMBOLS 1... Ionization chamber, 5... Sample, 7... Optical fiber bundle, 8... Laser light source, 9... Observation device,
11... Laser beam, 2.13, 14.15...
・Part of the mass separation system.

Claims (1)

[Claims] (1) Using a laser-excited ion source b) In a quality branch 41i device for solid samples or phases, the system is placed in close contact with the Vt71 subsystem and the solid sample is taken inside it. The ionization chamber is ionized and one end is -
1) a bundle of 7 aino\" placed in the vicinity of the solid sample described in 1- above; 5) A quality enemy component characterized in that it is designed to be easily connected to the observation means for observing the
1i device.