JPH0134277Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an X-ray source device in an X-ray photoelectron spectrometer.

X-ray photoelectron spectroscopy is a method for analyzing the surface of a sample, but it is a method that irradiates the sample surface with an electron beam and detects secondary electrons or X-rays emitted from the sample. Although it is a device that performs analysis, it is unique in that it can perform analysis to a depth of several hundred angstroms, and in order to perform analysis from the sample surface in the depth direction, the sample surface is removed by means such as ion bombardment. Another feature of this method is that it is a completely non-destructive analysis method, unlike methods that perform surface analysis.

The depth that can be analyzed with X-ray photoelectron spectroscopy increases as the energy of the X-rays used (characteristic X-rays of various elements are used) increases; however, on the other hand, the spectral width of characteristic X-rays generally increases as the energy increases. large,
Correspondingly, the peak width of the spectrum of X-ray photoelectrons becomes wider. That is, the higher the energy of the X-rays that excite the sample, the lower the resolution of X-ray photoelectron spectroscopy. Therefore, as for the energy of the sample excitation X-ray, it is desirable to select a characteristic X-ray with the lowest energy within the range that allows analysis to be performed to that depth, depending on the depth to be analyzed. For this reason, in conventional X-ray photoelectron spectroscopy, the X-ray source has to be replaced depending on the purpose of analysis. However, it is very troublesome to replace the X-ray source in an X-ray photoelectron spectrometer. However, the method of performing analysis by sequentially replacing the X-ray source is extremely troublesome and takes a very long time, and is difficult to implement except in special cases.

In view of the above-mentioned circumstances, the present invention aims to enable an X-ray photoelectron spectrometer to select any one of multiple types of X-ray sources for analysis simply by electrical switching operations. It was developed for the purpose of arranging multiple types of X-ray sources around the sample.
The present invention provides an X-ray source device in which the shape of the anode is optimal for X-ray irradiation of a sample. The present invention will be explained below with reference to Examples.

FIG. 1 shows an embodiment of the present invention. A1, A3
is an anode and as shown in Fig. 2, anode A2,
They are arranged to form a circular ring together with A4. Each anode is attached to a cooling block B, which is a rectangular tube bent into an annular shape, and cooling water flows through the cooling block B. Each anode A1~
A4 sheets are made of different materials. W is a Wehnelt electrode that is located below the anodes A1 to A4 and is an annular plate that is parallel and coaxial with the annular ring that the anodes A1 to A4 make up, and below this Wehnelt electrode is a filament F that makes up the anode. It is arranged in an annular shape parallel to and coaxial with the torus. S is a sample and is set slightly below the center position of the ring formed by the anodes A1 to A4. Each of the inner surfaces of the anodes A1 to A4 has a slope determined so that a perpendicular line erected at its center points toward the center position of the sample S, and is rotationally symmetrical with respect to the central axis of the ring formed by the anodes. be. In other words, the inner surface of each anode forms part of a concave conical surface whose axis is the central axis of the ring formed by the anode. The filament F has an annular shape as shown in FIG. 3, and has a terminal L1 at a position corresponding to the boundary between adjacent anodes A1 to A4.
~L4 is welded. With this configuration, for example, terminal L
When a power source is connected between F1 and L2, current mainly flows through the F1 portion of the filament, lighting F1. At this time, some current flows through filaments F4, F3, and F2, but the resistance of this part is three times that of F1, so the current is 1/3, which is not enough to make the filament red-hot, so the heat from this part is No electrons are emitted. Figure 4 shows filament F1~
The selection switching circuit of F4 is shown, and SW is a two-pole selection switch.

Returning to FIG. 1, a cylinder P is erected around the sample S, and an X-ray transparent window V is provided in this cylinder. Each window is covered with aluminum foil approximately 2μ thick. Both the inside and outside of the tube P are vacuum, but the reason why there is a window V separating the X-ray source and the sample is to prevent some of the electrons emitted from the filament F from hitting the sample S and being scattered or emitting secondary electrons. This is to prevent background from increasing during X-ray photoelectron detection.

For example, when the filament F1 is energized as described above, thermionic electrons emitted from F1 hit the anode A1 and cause A1 to emit X-rays. A1
The X-rays emitted from the window irradiate the sample S through the window V. The anodes A1 to A4 are electrically integrated and a high voltage is simultaneously applied to them. Filament F1
By selecting any one of F4 and energizing it, X-rays can be emitted from the corresponding anode.

When an anode is irradiated with an electron beam, continuous X-rays and characteristic X-rays are emitted from the anode.
Whereas characteristic X-rays are emitted almost uniformly in all directions or slightly strongly in oblique directions, characteristic It has a strong property in the perpendicular direction. In X-ray photoelectron spectroscopy, characteristic X-rays are used because the X-rays that excite the sample must have a known and constant energy. In the present invention, since the anode surface has a concave conical shape facing the sample, characteristic X-rays tend to concentrate on the sample, resulting in high X-ray irradiation efficiency.

The X-ray source device of the present invention has the above-described configuration, in which a plurality of X-ray sources are arranged in an annular shape surrounding the sample,
Since the X-ray source is selected based on which X-ray source's filament is energized, it is much easier to change the X-ray source and perform analysis, compared to handling each X-ray source one by one. Since the anode surface is a concave conical surface facing the sample, as described above, the X-ray irradiation efficiency of the sample is high and highly sensitive analysis is possible.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a longitudinal sectional view, FIG. 2 is a plan view, FIG. 3 is a bottom view, and FIG. 4 is a circuit diagram of a filament energization switching circuit. A1-A4...Anode, W...Ehnert electrode, F, F1-F4...Filament, S...Sample, B...Cooling block, P...Cylinder, V...X-ray transmission window, SW...Filament Changeover switch.

Claims (1)

[Scope of utility model registration request] A plurality of anodes made of different materials are arranged in a ring shape, and each anode is arranged so that the inner surface of the ring formed by these anodes forms a conical surface whose axis is a perpendicular line erected at the center of the ring. The inner surface of the anode is a part of a concave conical surface, and filaments are arranged in an annular manner coaxially with the annular ring on a plane parallel to the annular ring formed by the anode. An X-ray source device that allows a heating current to flow and has a place for setting a sample at the center of a ring formed by the anode.