JPS61142643A - X-ray source - Google Patents

Abstract

PURPOSE:To obtain soft X-ray of low exciting energy at a low cost by forming a protective film made of a material having a boiling point lower than that of an anode surface on the surface of the anode consisting of active metal and evaporating the protective film by heating means after mounting it on an X-ray source. CONSTITUTION:A copper block 4 serving as the base of an anode 2 is provided within an evaporating chamber, an evaporating film made of yttrium, etc. available for the material of the anode 2 is formed, and a protective film 3 made of magnesium, etc. having a boiling point lower than that the anode 2 is vacuum evaporated further thereon. Subsequently, the protective film 3 is mounted on a copper block 6 for cooling an X-ray source 1 to achieve vacuum exhaust, thereafter the protective film 3 is evaporated by heating of a heater 5 to expose a fresh surface of the anode 2 and the X-ray is generated by means of the thermal electron from a filament 8. Therefore, an X-ray can be obtained from a pure anode material with simplified constitution and at a low cost and furthermore analysis by the soft X-ray of low exciting energy can also be achieved at high accuracy.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is based on the ESC
pectroscopyror Chemical A
This invention relates to an X-ray source used for X-ray analysis such as analysis.

<Prior art> Conventionally, in ESCA, Mg (magnenium) or AI (aluminum) is usually used as an anode.
If you want to reduce the depth of analysis, it is necessary to use soft X-rays with low excitation energy, such as YMζ rays or ZrMζ rays, with an active metal such as Y (yttrium) or Zr (zirconium) as the anode. . However, even if active metals such as Y are deposited on the steel underlying the anode, they are quickly oxidized and deteriorated in the atmosphere, making them impractical. For this reason, there is a rotating anode method in which Y is vacuum-deposited on a rotating anode in a vacuum and irradiated with electrons from an electron gun. It is difficult and extremely expensive, so it is rarely practiced.

<Purpose> The present invention has been made in view of the above points, and has a simple configuration, low cost, and a low excitation energy soft
The purpose is to be able to use lines.

In the present invention, in order to achieve the above-mentioned object, a protective film made of a material having a boiling point or sublimation point lower than that of the active metal is formed on the surface of the anode made of an active metal. A heating means is provided relatively nearby.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

The X-ray source of this embodiment is applied to ESCA, and during analysis, thermionic electrons from the filament 8 are made to collide with the anode 2 to generate X-rays as will be described later. The generated X-rays pass through the X-ray window 11 and are irradiated onto a sample (not shown), and photoelectrons from the sample are detected and counted by analysis means (not shown).

In the X-ray source 1 of the present invention, the anode 2 on the surface of the copper block 4 is made of an active metal such as Y or Zr, and the surface of the anode 2 has a material whose boiling point or sublimation point is lower than that of the active metal. Materials such as Mg, Se (selenium), Zn (
A protective film 3 made of (zinc) is formed. In this embodiment, the anode 2 is made of Y and the protective film 3 is made of Mg.

Further, in the present invention, a heater is provided relatively near the anode 2, in this embodiment around the cooling copper block 6, as a heating means for evaporating and scattering the protective film 3 on the surface of the anode 2 as described later. 5 is provided.

In addition, 7 is an electrode, 9 is a cover, IO is an opening for evacuating the inside of the cover 9, 12 is a current terminal for the heater 5 and the filament 8, and 18 is cooling water.

The anode 2 and protective film 3 of the X-ray source 1 are formed by vacuum deposition on the copper block 4 underlying the anode 2, as shown in FIG. That is, a copper block 4 is placed in a vapor deposition chamber 13, Y as an anode 2 material is formed to a thickness of about 1 μm from a first vapor deposition source 14, and then Mg as a protective film 3 is formed from a second vapor deposition source 15. is formed to a thickness of several hundred angstroms. In this vacuum evaporation, a plurality of copper blocks 4 are arranged in the evaporation chamber 13, and it goes without saying that the anode 2 and the protective film 3 can be formed on a large number of copper blocks at the same time. In FIG. 2, reference numeral 6 indicates a vacuum pump for evacuating the inside of the deposition chamber 13 via a valve 17.

The copper block 4 on which the anode 2 and protective film 3 have been deposited in this manner is taken out of the deposition chamber 3 and attached to a cooling steel block 6 as shown in FIG. When taken out from the vapor deposition chamber 13, the surface of the copper block 4 is exposed to the atmosphere and is oxidized, but the Mg of the protective film 3 forms an immovable deaf film on the surface, so that the inside of the copper block 4 is not oxidized. There is no. Therefore, Y remains in the metal state within the protection M4343.

Next, when performing an analysis, first, after high vacuum evacuation, a portion of the copper block 4 is heated by the heater 5. As the heating progresses to around 650° C., Mg in the protective film 3 sublimates and adheres to the X-ray window 11 and the cover 9. Since the Mg is deposited to a very thin thickness, the amount of Mg sublimated is small, and the transmission characteristics of the X-ray window 11 are not significantly degraded. Also,
At this heating temperature, that is, 650°C, the Y of anode 2
does not change. Therefore, after sublimation of Mg, the copper block 4
Only the fresh Y layer appears on top. Since this Y layer is already in a high vacuum, it remains in that state for a long time. Thereafter, as in the conventional case, thermionic electrons from the filament 8 are made to collide with the anode 2 made of Y to generate soft X-rays with low excitation energy, and the sample is irradiated with the generated soft X-rays for analysis. Note that the heater 5 has the function of not only evaporating and scattering the protective film 3 but also removing adsorbed gas and increasing the degree of vacuum.

In this way, in the present invention, an active metal anode can be obtained with a simpler structure and at a lower cost than the above-mentioned rotating anode method, and analysis using soft X-rays with low excitation energy becomes possible.

<Effects> As described above, according to the present invention, a protective film made of a material having a boiling point or sublimation point lower than that of the active metal is formed on the surface of the anode made of an active metal, and Since the is equipped with a heating means, by evaporating and scattering the protective film using the heating means, it is possible to obtain an anode made of pure active metal with a relatively simple structure and at low cost. This will not only make it possible to conduct analytical research in fields that have traditionally been difficult using soft X-rays with low excitation energy using active metal anodes, but also improve analytical accuracy.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a diagram for explaining the procedure for forming an anode 2 and a protective film 3. As shown in FIG. I... X-ray source, 2... Anode, 3... Protective film, 4...
・Copper block, 5... Heater.

Claims (1)

[Claims] (1) An X-ray source that generates X-rays by making thermionic electrons from a filament collide with an anode, the anode being made of an active metal, and the surface of the anode having a boiling point or a temperature higher than that of the active metal. An X-ray source characterized in that a protective film made of a material with a low sublimation point is formed, and a heating means is provided relatively close to the anode.