JP2002243672A - X-ray analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray analyzer, capable of accurately comparing the sensitivities of the electronic spectroscopes of respective apparatuses. SOLUTION: The temperature of a measuring element 14 is raised due to the incidence of Alkα rays and scattered X-rays or the like impinge against measuring elements 14 and 16 to raise the temperatures of the measuring elements 14 and 16 in the same way. Since thermocouples 18 and 19 are connected differentially so as to detect the difference between the temperatures of the measuring elements 14 and 16, the voltage value, measured by a voltage measuring part 25, is changed by the temperature rise of the measuring element 14 due to only the absorption of Al kα rays. A control unit 26 calculates the X-ray intensity x0 of Al kαrays on the basis of the voltage signal from the voltage measuring part 25. Thereafter, the standard sample of the sample holder attached to a sample receiving stand 11 is irradiated with Al kαrays and the control unit 26 obtains the sensitivity of the electronic spectroscope, on the basis of the output signal intensity of the detector 32 and the X-ray intensity x0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an X-ray analyzer such as a photoelectron spectrometer.

[0002]

2. Description of the Related Art There are many analyzers utilizing X-rays.
Photoelectron spectroscopy is one of them. This photoelectron spectrometer is a device that irradiates a sample with X-rays from an X-ray source, detects photoelectrons generated from the sample by the irradiation, and analyzes the state together with the composition of a substance contained in the sample.

In this photoelectron spectroscope, Al or Mg is generally used as a target of an X-ray source, and X-rays generated from the target irradiate a sample. In some cases, these X-rays are monochromated by an X-ray monochromator and irradiated with a sample.

[0004] The energy of photoelectrons generated from the sample by X-ray irradiation is measured by an electron spectroscope. This electron spectrometer uses an input lens for decelerating photoelectrons and only photoelectrons of a certain energy among the decelerated photoelectrons. It consists of an analyzer to be selected and a detector to detect photoelectrons selected by the analyzer.

The sensitivity of the electron spectrometer is represented by the ratio (E _out / X _in ) between the intensity X _{in of the} X-ray incident on the sample and the output signal intensity E _out of the detector.
As the X-ray intensity X _in the current, the power applied to the X-ray source target is proportional to the X-ray intensity X _in is substituted.

[0006]

However, the intensity X _in of the X-ray incident on the sample changes depending on the incident angle of the electron beam on the X-ray source target, the operating distance, and the like. For this reason, when the sensitivity of the spectroscope is compared with the same spectroscopic condition of the electron spectroscope of each photoelectron spectroscope, the same type of X is used.
Even if the power applied to each X-ray source target using a radiation source the same, the incident X-ray intensity X _in to the sample in each device becomes different. Therefore, conventionally, the sensitivity of the electron spectrometer of each device has not been accurately compared.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and one of its objects is to provide an X-ray analyzer capable of accurately comparing the sensitivities of electron spectrometers of respective devices. It is in.

[0008]

An X-ray analyzer according to the present invention that achieves this object irradiates a sample with X-rays from an X-ray source and detects a signal generated from the sample by the X-ray irradiation. An X-ray analyzer for analyzing a sample, comprising X-ray intensity measurement means for measuring the intensity of X-rays from the X-ray source, the X-ray intensity measurement means comprising: a detector holder arranged in a sample chamber; A first probe attached to the detector holder and receiving X-ray irradiation from the X-ray source; and a first probe attached to the detector holder and having substantially the same shape and material as the first probe. Detecting a difference between the temperature of the second tracing stylus not receiving X-ray irradiation from the X-ray source and the temperature of the first tracing stylus and the temperature of the second tracing stylus, and detecting the difference between the detected temperatures. Means for obtaining the intensity of X-rays from the X-ray source based on the signal of

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of a photoelectron spectroscopy apparatus shown as an example of the X-ray analysis apparatus of the present invention. First, FIG.
The configuration of the device will be described.

In FIG. 1, reference numeral 1 denotes a sample chamber. Reference numeral 2 denotes an X-ray source arranged in a sample chamber in the chamber 1, and an X-ray source 2 includes a filament 3 for generating electrons.
And a focus adjustment electrode 5 for focusing an electron beam generated by the filament 3 on the target 4.

In this X-ray source, a voltage is applied between the filament 3 and the target 4 for accelerating the electrons generated in the filament 3 toward the target 4. Emanates from the target.

Reference numeral 6 denotes an X-ray monochromator spectral crystal curved in a double focusing type.
Is disposed in the chamber so as to face the X-ray source 2. The X-ray monochromator spectral crystal 6 is formed of crystal [α-SiO 2], and the target 4
The X-rays generated in step (1) are separated by the X-ray monochromator 6 and are converted into monochromatic Alkα rays.

Reference numeral 7 denotes an inclination adjusting means arranged in the chamber 1, and an inclination stage 8 is attached to the inclination adjusting means 7. The tilt stage 8 includes a tilt adjusting unit 7.
Is adjusted to tilt around an axis y ′ parallel to the y-axis.

An XY stage 9 is attached to the tilt stage 8 so as to be movable in the XY directions.
The sample receiving table 1 is mounted on the stage 9 via an electrical insulating member 10.
1 is fixed.

In a normal sample analysis, a sample holder holding a sample is attached to the sample holder 11. In FIG. 1, an X-ray detection holder 12 is attached to the sample holder 11. I have.

FIG. 2 is a view of the X-ray detection holder 12 shown in FIG. 1 as viewed from the side of the X-ray monochromator spectral crystal 6, and the structure of the X-ray detection holder 12 is shown in FIG. Referring to FIG. 2 (top view), reference numeral 13 denotes a conductive detector container (detector holder). This detector container 13
Is attached to the sample receiving table 11 as shown in FIG.

Reference numeral 14 denotes a first measuring element serving as a heat bath;
As the first probe 14, for example, a block of pure copper (for example, 10 mm × 10 mm × 2 mm) is used. The first probe 14 is attached to the detector container 13 via a quartz fiber 15 which is a thermal and electrical insulator.

Reference numeral 16 denotes a second tracing stylus. The second tracing stylus 16 has the same shape and material as the first tracing stylus 14. That is, the second tracing stylus 16
Is a block of pure copper, the size of which is (10 mm × 10
mm × 2 mm). The second tracing stylus 16 is attached to the detector container 13 via a quartz fiber 17, and the second tracing stylus 16 and the first tracing stylus 14 are
They are arranged side by side in the detector container 13 at a certain distance. The surfaces of the tracing styluses 14 and 16 are coated with carbon vapor or aquadac to improve absorption of X-rays and the like and reduce emitted electrons.

The first tracing stylus 14 and the second tracing stylus 16
, Thermocouples (for example, copper-constantan) 18 and 19 for temperature detection are respectively attached. The two thermocouples 18 and 19 are connected in series by connecting wires of one material (for example, constantan), and terminals 21 and 22 (for which wires of another material (for example, copper) are fixed to the detector container 13) For example, made of copper).
As a result, the two thermocouples are differentially connected.
The differential outputs of the two thermocouples are taken out at 1 and 22.
These terminals 21 and 22 are connected to a voltage measuring unit 25 outside the vacuum via conducting wires 23 and 24, respectively, and the voltage measuring unit 25 is connected to a control device 26. By connecting the thermocouples as shown in FIG.
2 is a copper wire, so that there is no contact potential between the terminals 21 and 22 and the thermocouple.

Further, as shown in FIG.
Is a terminal 2 fixed to the container 13 via the lead wire 27.
8 and the terminal 28 is grounded.

As shown in FIG. 1, an electron spectroscope 29 for detecting photoelectrons emitted from the sample at the time of sample analysis is disposed above the X-ray detection holder 12.
The electron spectroscope 29 includes an input lens (deceleration lens) 30 including a plurality of electrostatic lenses, and a hemispherical analyzer 3.
1 and a detector 32. The detector 32 is connected to the control device 26.

Reference numeral 33 denotes an exhaust device, and the inside of the chamber 1 is evacuated to an ultra-high vacuum by the exhaust device 33.

The configuration of FIG. 1 has been described above. Next, the sensitivity measurement of the electron spectrometer in this apparatus will be described.

Firstly, Opereta adjusts the like amount of current flowing in the filament 3 of the X-ray source 2, to set the power applied to the target to a predetermined value W _0. Such an X-ray source 2
With the adjustment described above, the electrons generated in the filament 3 irradiate the target 4, and X-rays are generated from the target 4.

The X-rays generated by the target 4 are separated by the X-ray monochromator crystal 6 and converted to monochromatic Alkα rays. The Alkα rays are, as shown by oblique lines in FIGS. To the tracing stylus 14. The operator observes the photoelectron spectroscopy spectrum of the first tracing stylus 14 in order to make the Alkα ray incident on the first tracing stylus 14, and moves the XY stage so that the intensity of the spectrum becomes strong. The probe 14 is moved to position the probe 14.

As described above, the first tracing stylus 14 has Al
When the kα ray is irradiated, the temperature of the probe 14 that has absorbed the Alkα ray rises.

On the other hand, the Alkα ray is
Is not irradiated, but scattered X-rays generated by the X-ray
Since the line, the scattered electrons, the scattered light, and the like impinge on the second stylus 16, the temperature of the second stylus 16 slightly increases.
The scattered X-rays, scattered electrons, scattered light, and the like also hit the first tracing stylus 14 near the second tracing stylus 16, and the temperature of the first tracing stylus 14 is affected by the influence. It rises in the same manner as the second probe 16. As described above, the temperature rise of the first tracing stylus 14 includes the background component due to the irradiation of scattered X-rays and the like in addition to the component due to the absorption of the Alkα ray.

However, as shown in FIGS.
Since the thermocouples 18 and 19 are differentially connected so as to detect the difference between the temperature of the first tracing stylus 14 and the temperature of the second tracing stylus 16, the thermocouples 18 and 19 are connected to the voltage measured by the voltage measuring unit 25. Does not include a voltage component corresponding to the background component described above. That is, the voltage value measured by the voltage measuring unit 25 is the first tracing stylus 14 only due to the absorption of the Alkα ray.
It changes with the temperature rise.

The voltage measuring section 25 sends a signal V representing the detected voltage to the control device 26. Then, the controller 26 first determines the amount of change of the voltage measured by the voltage measuring unit 25 based on the voltage signal V from the voltage measuring unit 25 in order to determine the amount of the Alkα ray incident on the first tracing stylus 14. x
[V / s] is obtained. At this time, when the control device 26 starts irradiating the first tracing stylus 14 with X-rays, the control device 26
The voltage change amount x [V / s] is obtained in a region where the voltage value measured in Step (1) increases almost linearly.

Since information on the specific heat and mass of the first tracing stylus 14 and the quantum energy of the Alkα ray has been input to the control device 26 in advance, the control device 26 calculates the voltage change x [V / s] to the first probe 14
Is converted to x ₀ [photons / s] by using the specific heat and mass of the sample and the quantum energy of Alkα ray. This makes it possible to convert the power applied to the conventional X-ray target into an incident X-ray dose.

When the X-ray intensity measurement using the X-ray detection holder 12 has been completed in this way, the operator removes the X-ray detection holder 12 from the sample receiving base 11, and this time the sample holding the standard sample is removed. The holder is attached to the sample holder 11.

Further, the operator operates the electron spectrometer 2
9 are set to predetermined conditions.

Then, the X-ray intensity is x ₀ [phot
ons / s] to the standard sample.
Photoelectrons generated from the sample by the irradiation are detected by the electron spectroscope 29. At this time, of the photoelectrons generated from the sample, only the photoelectrons generated from a predetermined region on the sample are detected, and the region is determined by the lens conditions of the input lens 30.

The output signal of the detector 32 of the electron spectrometer 29 is sent to the controller 26, the controller 26 is an electronic spectroscope 29 on the basis of the output signal intensity _{E out} of the detector 32 X-ray intensity _{x 0} Find the sensitivity of

Although the apparatus shown in FIG. 1 has been described above, the apparatus shown in FIG. 1 directly detects X-rays irradiating the sample, obtains the intensity of X-rays incident on the sample, and obtains the obtained intensity and electron intensity. The sensitivity of the electron spectrometer is determined based on the output signal strength of the spectrometer.

For other photoelectron spectroscopy devices of the same type, if the sensitivity of the electron spectrometer is determined in the same manner as in the case of the device of FIG. 1, even if there is a difference in the X-ray dose generated by each X-ray source. The sensitivity of the electron spectrometer of each device can be accurately compared.

The present invention is not limited to the above example.

For example, in the above example, the X-ray detection holder 12 is mounted on the sample receiving table 11, but a dedicated X-ray intensity measuring mechanism holding the X-ray detection holder 12 is always disposed in the sample chamber. You may make it.

This X-ray intensity measuring mechanism has a structure in which the X-ray detecting holder 12 is incorporated on a position variable mechanism using a bellows having a variable working distance, and is shown in FIG. 1 only when measuring X-ray intensity. X-ray detection holder 1 at sample analysis position
2 is arranged. After completion of the X-ray intensity measurement, the position variable mechanism using the bellows is operated to retract the X-ray detection holder 12 from the sample analysis position.
Normal sample analysis can be performed. In this case,
The X-ray intensity measurement mechanism becomes an independent mechanism by incorporating the current introduction terminal into the flange on the bellows side.

Although not shown in FIG. 1, in practice, when the detector container 13 is mounted on the sample holder 11, the terminals 21, 22, and 28 are respectively connected to terminal receivers on the holder 11 side. You. The terminal receiver connected to the terminals 21 and 28 is connected to the voltage measuring unit 25 via the conductive wires 23 and 24 provided in the inclination adjusting means 7.

[Brief description of the drawings]

FIG. 1 is a schematic view of a photoelectron spectroscopy apparatus shown as an example of the present invention.

FIG. 2 is a top view of the X-ray detection holder 12. FIG.

[Explanation of symbols]

1. Sample chamber, 2. X-ray source, 3. Filament,
4 target, 5 focus adjusting electrode, 6 X-ray monochromator spectral crystal, 7 tilt adjusting means, 8 tilt stage, 9 XY stage, 10 electrical insulating member, 11
... Sample holder, 12 ... X-ray detecting holder, 13 ... Detector container, 14 ... First measuring element, 15, 17 ... Quartz fiber, 16 ... Second measuring element, 18, 19 ... Thermocouple, 21 ,
22, 28 terminal, 23, 24 conductor, 25 voltage measuring unit, 26 controller, 27 lead wire, 29 electron spectrometer, 30 input lens, 31 hemispherical analyzer, 32 detector , 33 ... exhaust system

Claims (4)

[Claims] An X-ray analyzer for irradiating a sample with X-rays from an X-ray source, detecting a signal generated from the sample by the X-ray irradiation, and analyzing the sample, wherein the X-rays from the X-ray source are provided. X-ray intensity measurement means for measuring the intensity of the X-ray source, the X-ray intensity measurement means is attached to the detector holder disposed in the sample chamber and the detector holder, and X-ray irradiation from the X-ray source A first tracing stylus to be received and a second tracing stylus attached to the detector holder and having substantially the same shape and material as the first tracing stylus and not receiving X-ray irradiation from the X-ray source Means for detecting a difference between the temperature of the first tracing stylus and the temperature of the second tracing stylus and obtaining the intensity of X-rays from the X-ray source based on the detected temperature difference signal An X-ray analyzer, comprising: 2. The method according to claim 1, wherein the first and second probes are:
A thermocouple for temperature detection is attached to each,
The X-ray analyzer according to claim 1, wherein the two thermocouples are connected in series so as to generate a temperature difference output between the probes. 3. The X-ray according to claim 1, wherein the first and second probes are attached to the detector holder via thermal and electrical insulation members. Analysis equipment. 4. The X-ray analyzer is a photoelectron spectrometer that detects photoelectrons generated from a sample by X-ray irradiation with an electron spectrometer, and outputs the X-ray intensity measuring means output and the electron spectrometer output. 4. An X-ray analysis apparatus according to claim 1, further comprising means for obtaining the sensitivity of the electron spectrometer based on the X-ray spectrometer.