JPS61140041A - Multi-spectral x-ray generating tube - Google Patents

Abstract

PURPOSE:To generate many characteristic X-rays with a single X-ray generating tube by irradiating an arbitary element metal among a plurality of kinds of target element metals with electron beams while controlling a direction of the irradiation of the electron beams in a X-ray target formed by arranging said element metals thereon. CONSTITUTION:Photoelectrons emitted from a photoelectron emission layer 2 by irradiating it with a light beam from a light source for irradiating the photoelectron emission layer and converged by a converging electric field formed by a converging electrode 4, and allowed to enter into a deflection space, with which a multi-target surface 5 of a berrylium plate allowing X-rays from an opposing surface to transmit therethrough is irradiated. Target element metals 6a through 6c are arranged on the multi-target surface in a line as shown in the accompanying drawings. In addition, deflection voltage is applied between deflection electrodes 3a, 3b from a deflection voltage source 7. Hereby, electron beams can be directed to an arbitrary element metal by changing deflection voltage of a deflection voltage source 7, and hence the element electrode so irradiated with the electron beams can emit characteristic X-rays peculier to the electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multispectral X-ray generating tube that can generate a plurality of characteristic X-rays with a single X-ray generating tube.

The multispectral X-ray generator tube according to the present invention can be used for analysis of temporal changes in crystal structure by crystal diffraction, high time-resolved measurements, etc.

(Prior art) A normal X-ray generator heats a cathode with a heater to generate thermoelectrons, and forms a thin electron beam with an electrostatic focusing system.
It is configured to irradiate a target and generate X-rays.

Hot cathode type electrodes do not allow high frequency response and cannot meet the demand for obtaining sharp pulsed X-rays.

In order to meet this demand, the inventor of the present invention has already proposed an X-ray generating tube (Japanese Patent Application No. 153,663/1982) using a photocathode as an electron source.

According to this proposal, an electron beam generated from a photoelectron gun is made to collide with an X-ray target disposed at the other end facing the photoelectron gun, thereby generating characteristic X-rays from the target material. FIG. 4 shows an example of characteristic X-rays generated when titanium (T i ) is used as the target.

Since the X-ray generating tube according to the above proposal uses a photoelectron gun (photocathode), it has the advantage of being able to obtain characteristic X-rays with a sharp pulse curve by exciting the photocathode with a laser light source or the like. It has some characteristics.

However, recently there have been requests to perform measurements using several types of characteristic X-rays, and in such cases, Cooget's f! It is necessary to prepare a plurality of X-ray generating tubes of different types.

(Object of the Invention) An object of the present invention is to provide a multispectral X-ray generating tube that can generate a large number of characteristic X-rays with a single X-ray generating tube.

(Structure of the Invention) In order to achieve the above object, a multispectral X-ray generating tube according to the present invention includes a vacuum vessel, a photoelectron emission layer formed in the vacuum vessel, and photoelectrons generated by the photoelectron emission layer. an electron lens that converges and projects the electron beam in a certain direction; an X-ray target formed by arranging a plurality of types of target element metals toward the direction in which the electron beam arrives; and a deflector that deflects the electron beam so as to control and irradiate any elemental metal of the X-ray target.

(Example) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.

FIG. 1 is a sectional view showing a first embodiment of the multispectral X-ray generating tube according to the present invention, and FIG.
FIG. 3 is a cross-sectional view showing the relationship between the deflection electrode and the target element metal in the example.

A photoelectron emission layer 2 is formed on the inner surface of the open container 1 .

The photoelectrons emitted from the photoelectron emission layer 2 by being irradiated with the light beam 10 from the photoelectron emission layer irradiation light source are transferred to the focusing electrode 4.
The beam is focused by the focusing electric field generated by the beam and propagates into the deflection space. Beryllium (Be) that allows X-rays to pass through the surface opposite to the surface on which the photoelectron emission layer 2 is formed.
A multi-target surface 5 of Ni is provided.

On this surface, target element metals 6a, 6b, and 5c are arranged in one row as shown.

A deflection voltage is applied from a deflection voltage source 7 between the deflection electrodes 3a and 3b. The electron beam focused by the focusing electrode 4 is deflected between the deflection electrodes 3a and 3b.

By changing the deflection voltage of the deflection voltage source 7, the electron beam can be directed to any element metal. The elemental metal irradiated with the electron beam emits characteristic X-rays specific to that metal.

In this example, three types of metals are selected from the following metals. It shows the characteristic X-ray energy of each metal.

Titanium (Ti) 4.5 KeV Vanadium (V) 4.96 KeV Chromium (Cr) 5
．． 42KeV Iron (Fe) 6.40KeV Cobalt (Co) 6.92KeV Ni'r (Ni) 7.47KeVail (Cu)
8.04 KeV The time width of this characteristic X-ray can be made as short as the pulse width of the light that irradiates the photoelectron emission layer.

Therefore, it is possible to arbitrarily control from ultra-short X-ray pulses using ultra-short laser light to DC X-rays when direct current light is irradiated.

FIG. 3 is a sectional view showing the relationship between the deflection electrode and the metal target element of a second embodiment of the multispectral X-ray generating tube according to the present invention.

This embodiment uses vertical deflection electrodes 3a, 3b and horizontal deflection electrodes 3c, 3d, so that the electron beam can be deflected two-dimensionally.

On a multi-target surface 5 of a helium (Be) plate that transmits X-rays, elemental metals 6e to 6p are arranged in a plane as shown.

A deflection voltage source 7 (not shown) is provided between the deflection electrodes 33 to 3d.
A deflection voltage is applied to the electron beam, and the electron beam is deflected two-dimensionally.

Thereby, different characteristic X-rays can be obtained by sequentially selecting arbitrary element metals.

(Modifications) Various modifications can be made to the embodiments described in detail above within the scope of the present invention.

In each of the above embodiments, an electrostatic deflection type deflector is used, but a well-known electromagnetic deflection type deflector can also be used.

(Effects of the Invention) As described in detail above, in the multispectral X-ray generating tube according to the present invention, a large number of different characteristic X-rays can be obtained with a single X-ray tube.

Since elemental metals in the field can be selected at high speed sequentially using the deflector, highly time-resolved measurements, which were previously impossible, become possible.

It can also be used to analyze temporal changes in crystal structure using crystal diffraction.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of a multispectral X-ray generating tube according to the present invention. FIG. 2 is a sectional view showing the relationship between the deflection electrode and the target element metal in the embodiment. FIG. 3 is a sectional view showing the relationship between the deflection electrode and the target element metal in a second embodiment of the multispectral X-ray generating tube according to the present invention. FIG. 4 is a graph showing an example of a characteristic X-ray spectrum. 1... Vacuum container 2... Photoelectron emission layer 3... Deflector 3a, 3b, 3d, 3e --- Deflection electrode
14...Focusing electrode 5...Multi-target surfaces 6a-c, 5e-p...Target element metal 7.
・・Deflection power supply

Claims (4)

[Claims] (1) A vacuum container, a photoelectron emission layer formed in the vacuum container, an electron lens that converges photoelectrons generated by the photoelectron emission layer and projects them in a fixed direction as an electron beam, and arrival of the electron beam. an X-ray target formed by arranging a plurality of types of target element metals in the direction of A multispectral X-ray generating tube consisting of a deflector that deflects. (2) The multispectral X-ray generating tube according to claim 1, wherein the deflector is an electrostatic deflector or an electromagnetic deflector. (3) The multispectral X-ray generating tube according to claim 1, wherein the deflector is a one-dimensional or two-dimensional deflector. (4) The target element metal is Ti, V, Cr, Fe.
2. The multispectral X-ray generating tube according to claim 1, wherein the tube is selected from , Co, Ni, and Cu.