X-ray analyzer and control method for the X-ray analyzer

Abstract

To improve sample analysis accuracy while reducing sample damage.SOLUTION: An EPMA 100 according to an aspect comprises a spectrometer 6 and a control unit 10. The spectrometer 6 is a wavelength-dispersive type and configured to detect characteristic X-rays generated from a sample S irradiated with an electron beam. The control unit 10 moves the spectrometer 6. The control unit 10 generates a spectrum of the sample based on the characteristic X-rays detected by the spectrometer 6 while moving the spectrometer 6, and changes movement speed of the spectrometer 6 while the spectrometer 6 is being moved.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an X-ray analyzer and a method for controlling the X-ray analyzer.

Background Art

[0002] For example, Japanese Unexamined Patent Application Publication No. 2021-179329 (Patent Document 1) discloses an electron probe microanalyzer (EPMA) as an example of an X-ray analyzer for analyzing a sample. The X-ray analyzer irradiates an electron beam onto the sample and detects characteristic X-rays generated from the sample while moving a spectroscope. Further, the X-ray analyzer generates a spectrum based on the detected characteristic X-rays. Then, the X-ray analyzer analyzes the sample based on the generated spectrum.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an X-ray analyzer, it is desired to improve the analysis accuracy of a sample. In order to improve the analysis accuracy of the sample, it is preferable to improve the S / N ratio of the spectrum. In order to improve the S / N ratio of the spectrum, for example, it is preferable to reduce the moving speed of the spectroscope. However, when the moving speed of the spectroscope is reduced, the irradiation time of the electron beam on the sample becomes long, which may cause damage to the sample.

[0005] The present invention has been made to solve such problems, and an object thereof is to provide an X-ray analyzer and a method for controlling the X-ray analyzer that can improve the analysis accuracy of a sample while reducing damage to the sample. [Means for solving the problem]

[0006] An X-ray analyzer according to one embodiment comprises a detection mechanism and a control device. The detection mechanism is a wavelength-dispersive detection mechanism configured to detect characteristic X-rays generated from a sample irradiated with an electron beam. The control device moves the detection mechanism. While moving the detection mechanism, the control device generates a spectrum of the sample based on the characteristic X-rays detected by the detection mechanism and changes the movement speed of the detection mechanism during its movement.

[0007] In a control method for an X-ray analyzer according to one embodiment, the X-ray analyzer includes a wavelength-dispersive detection mechanism configured to detect characteristic X-rays generated from a sample irradiated with an electron beam. The control method comprises generating a spectrum of the sample based on the characteristic X-rays detected by the detection mechanism while moving the detection mechanism. Generating the spectrum includes changing the movement speed of the detection mechanism while it is moving. [Effects of the Invention]

[0008] The X-ray analyzer and control method for the X-ray analyzer described herein can improve the accuracy of sample analysis while reducing damage to the sample. [Brief explanation of the drawing]

[0009] [Figure 1] This is an overall configuration diagram of the EPMA in this embodiment. [Figure 2] This is a diagram illustrating the spectrum used to explain state analysis. [Figure 3] This is a diagram intended to explain the concept behind this disclosure. [Figure 4] This figure illustrates an example of another spectrum. [Figure 5] This is a functional block diagram of the control unit. [Figure 6] This is a diagram illustrating an example of the first mode screen. [Figure 7] This is a diagram illustrating an example of the second mode screen. [Figure 8] It is a diagram for explaining an example of the first speed DB. [Figure 9] It is a diagram for explaining an input screen. [Figure 10] It is a diagram for explaining a provisional spectrum. [Figure 11] It is a diagram for explaining the second speed DB. [Figure 12] It is a diagram for explaining a plot and a spectrum. [Figure 13] It is a flowchart of the processing of the control device when the sample type input mode is set. [Figure 14] It is a flowchart of this analysis. [Figure 15] It is a flowchart of the processing of the control device when the first pre-analysis mode is set. [Figure 16] It is a flowchart of the processing of the control device when the second pre-analysis mode is set. [Figure 17] It is a flowchart of the processing of the control device when the third pre-analysis mode is set. [Figure 18] It is a flowchart of the processing of the control device when the no pre-analysis mode is set.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions will not be repeated.

[0011] [Configuration Example] FIG. 1 is an overall configuration diagram of an EPMA which is an example of an X-ray analyzer according to the present embodiment. Note that the X-ray analyzer according to the present disclosure is not limited to an EPMA that irradiates an electron beam on a sample, and may be a fluorescence X-ray analyzer that irradiates an X-ray on a sample and spectroscopically analyzes characteristic X-rays by WDS.

[0012] Referring to FIG. 1, the EPMA 100 includes an electron gun 1, a deflection coil 2, an objective lens 3, a sample stage 4, a sample stage drive unit 5, a plurality of spectrometers 6a, 6b, and a plurality of drive mechanisms 65a, 65b. The EPMA 100 further includes a control device 10, a deflection coil control device 12, an input device 13, and a display device 14. The electron gun 1, the deflection coil 2, the objective lens 3, the sample stage 4, and the spectrometers 6a, 6b are provided in a measurement chamber (not shown). During the analysis of the sample, the measurement chamber is evacuated to a vacuum state.

[0013] The electron gun 1 is an excitation source that generates an electron beam irradiated onto the sample S on the sample stage 4. The electron gun 1 corresponds to the "output source" of the present disclosure. In the present embodiment, the configuration in which the electron beam is an electron ray will be described. However, the electron beam may be other beams, for example, X-rays. Further, the control device 10 can adjust the beam current of the electron beam E by controlling a convergence lens (not shown). The deflection coil 2 forms a magnetic field by a drive current supplied from the deflection coil control device 12. The magnetic field formed by the deflection coil 2 can deflect the electron beam E.

[0014] The objective lens 3 is provided between the deflection coil 2 and the sample S placed on the sample stage 4, and narrows the electron beam E that has passed through the deflection coil 2 to a small diameter. The electron gun 1, the deflection coil 2, and the objective lens 3 constitute an irradiation device that irradiates an electron beam toward the sample. The sample stage 4 is a stage for placing the sample S, and is configured to be movable in a horizontal plane by the sample stage drive unit 5.

[0015] The EPMA 100 can two-dimensionally scan the irradiation position of the electron beam E on the sample S by at least one of the driving of the sample stage 4 by the sample stage drive unit 5 and the driving of the deflection coil 2 by the deflection coil control device 12. When the scanning range is relatively narrow, scanning is performed by the deflection coil 2, and when the scanning range is relatively wide, scanning is performed by moving the sample stage 4.

[0016] Spectrometers 6a and 6b are instruments for detecting characteristic X-rays emitted from a sample S irradiated with an electron beam E. In this example, two spectrometers 6a and 6b are shown, but the number of spectrometers is not limited to these; there may be one, three or more, or more. The configuration of each spectrometer is the same except for the spectroscopic crystal.

[0017] The spectrometer 6a includes a spectroscopic crystal 61a, a detector 63a, and a slit 64a. The spectrometer 6a is housed in a casing. The irradiation position of the electron beam E on the sample S, the spectroscopic crystal 61a, and the detector 63a are located on a Rowland circle (not shown). The drive mechanism 65a moves the spectroscopic crystal 61a along a straight line 62a while tilting it, and the detector 63a rotates as shown in accordance with the movement of the spectroscopic crystal 61a so that the incidence angle θ and emission angle of the characteristic X-rays relative to the spectroscopic crystal 61a satisfy Bragg's diffraction conditions. This allows for wavelength scanning of the characteristic X-rays emitted from the sample S. In this way, the spectroscopic crystal 61a and the detector 63a move together as a single unit.

[0018] Spectrometer 6b includes a spectroscopic crystal 61b, a detector 63b, and a slit 64b. The drive mechanism 65b causes the spectroscopic crystal 61b to move along a straight line 62b while being tilted, and the detector 63b rotates as shown in the figure in accordance with the movement of the spectroscopic crystal 61b so that the incidence angle θ and emission angle of characteristic X-rays to the spectroscopic crystal 61b satisfy Bragg's diffraction condition. The configuration of spectrometer 6b is the same as that of spectrometer 6a except for the spectroscopic crystal, so the explanation will not be repeated. Note that the configuration of each spectrometer is not limited to the above configuration, and various known configurations can be adopted.

[0019] Spectrometers 6a and 6b may be collectively referred to as "Spectrometer 6." Spectrometer 6 corresponds to the "Detection Mechanism" in this disclosure. Spectrometer 6 is a Wavelength Dispersive Spectrometer (WDS) configured to detect characteristic X-rays generated from a sample. Furthermore, in the following, spectroscopic crystals 61a and 61b may be collectively referred to as "Spectroscopic Crystal 61," detectors 63a and 63b may be collectively referred to as "Detector 63," and drive mechanisms 65a and 65b may be collectively referred to as "Drive Mechanism 65."

[0020] The control device 10 comprises a CPU (Central Processing Unit) 20, memory 22, and an input / output interface (not shown) for inputting and outputting various signals. The memory 22 includes, for example, ROM (Read Only Memory) and RAM (Random Access Memory). The CPU 20 loads the program stored in ROM into RAM and executes it. The program stored in ROM is a program that describes the processing procedure of the control device 10. The ROM also stores various tables (maps) used for various calculations. The control device 10 executes various processes in the EPMA 100 according to these programs and tables. The processing is not limited to software; it can also be executed by dedicated hardware (electronic circuits). The control device 10 controls the drive mechanism 65, the sample stage drive unit 5, the display image of the display device 14, etc. The control device 10 is also called a control circuit.

[0021] The control device 10 receives a detection signal from the detector 63. This detection signal indicates the intensity of the characteristic X-rays input to the detector 63. Based on the input detection signal, the control device 10 creates the X-ray spectrum of the object to be analyzed (hereinafter also simply referred to as the "spectrum"). In other words, the control device 10 generates the spectrum of the sample based on the characteristic X-rays detected by the spectrometer 6 while moving the spectrometer 6.

[0022] The control device 10 analyzes the sample S based on the spectrum it has created. For example, the control device 10 creates a standard spectrum by analyzing a standard sample. A standard sample is a sample whose components are known. Furthermore, the control device 10 creates an unknown spectrum by analyzing the unknown sample to be analyzed. Then, the control device 10 analyzes the unknown sample based on the known spectrum and the unknown spectrum.

[0023] The deflection coil control device 12 controls the drive current supplied to the deflection coil 2 according to instructions from the control device 10. By controlling the drive current according to a predetermined drive current pattern (magnitude and change speed), the irradiation position of the electron beam E on the sample S can be scanned at a desired scanning speed.

[0024] The input device 13 is an input device for the analyst to give various instructions to the EPMA 100, and is composed of, for example, a mouse or keyboard. The display device 14 is an output device for providing various information to the analyst, and is composed of, for example, a display equipped with a touch panel that the analyst can operate. This touch panel may also be used as the input device 13.

[0025] Furthermore, as mentioned above, the incident angle θ and exit angle of the characteristic X-rays satisfy Bragg's diffraction conditions. That is, the following equation (1) holds true.

[0026] λ = (2d / n)·sinθ (1) Here, λ represents the wavelength of the characteristic X-ray, d represents the spacing between the lattice planes of the spectroscopic crystal 61, and n represents a positive integer. That is, "n / 2d" on the right side of Equation (1) is a constant. Therefore, the wavelength λ of the X-ray input to the detector 63 is a value corresponding to θ. In the example of FIG. 1, 0 < Sinθ < 1. Thus, the larger the value of θ, the larger the wavelength λ of the X-ray input to the detector 63. That is, the positions of the spectroscopic crystal 61 and the detector 63 (the position of the spectroscope 6), the value of θ, and the wavelength λ of the X-ray input to the detector 63 correspond to each other. In other words, the wavelength band of the generated spectrum and the movement period of the spectroscopic crystal 61 and the detector 63 correspond to each other. In the example of FIG. 1, θA and θB are shown as the incident angles θ. Also, θB > θA.

[0027] Further, the control device 10 moves the spectroscope 6 by controlling the drive mechanism 65. The movement of the spectroscope 6 is the above-described integrated movement of the spectroscopic crystal 61 and the detector 63.

[0028] The drive mechanism 65 is constituted by, for example, a stepping motor or the like. The control device 10 moves the spectroscope 6 by outputting a pulse signal to the drive mechanism 65. Also, the control device 10 can control the moving speed of the spectroscope 6 by controlling the output interval of the pulse signal. Thus, the control device 10 can change the moving speed of the spectroscope 6 during the movement of the spectroscope 6 (during the analysis of the sample S). Hereinafter, the control for changing the moving speed is also referred to as "speed change control".

[0029] As described above, the positions of the spectroscopic crystal 61 and the detector 63 (the position of the spectroscope 6) and the wavelength λ of the X-ray input to the detector 63 correspond to each other. Also, the control device 10 can recognize an important wavelength band in the generated spectrum based on an input from the user or by the control device 10 itself. Therefore, the control device 10 of the present embodiment can change the moving speed of the spectroscope 6 (the spectroscopic crystal 61 and the detector 63) during the period when X-rays having wavelengths included in the important wavelength band are input to the detector 63.

[0030] Next, we will explain the types of analysis that the EPMA100 can perform. The spectral peaks of a particular element can change depending on the chemical bonding state of that element, resulting in variations in wavelength position, spectral shape, and spectral peak intensity ratio. Using this phenomenon, the EPMA100 can analyze the chemical bonding state of a target element contained in an unknown sample. Chemical bonding states include, for example, elemental metals, oxides, carbides, nitrides, and sulfides. Thus, the EPMA100 can analyze the chemical bonding state of an unknown sample. This analysis is also called "state analysis." In addition to state analysis, the EPMA100 can also perform qualitative and quantitative analysis. Qualitative analysis is an analysis that identifies the elements contained in an unknown sample. Quantitative analysis is an analysis that identifies the concentration or content of components contained in an unknown sample. The user can select one of the following modes: state analysis mode, qualitative analysis mode, or quantitative analysis mode.

[0031] Figure 2 shows spectra to illustrate state analysis. In the example in Figure 2, the spectra of SiKβ1 and SiKβ1' of a standard Si sample (STD) are shown. In this disclosure, in figures showing spectra such as Figure 2, the horizontal axis represents wavelength and the vertical axis represents intensity.

[0032] In the example in Figure 2, the solid line shows the spectrum of a standard sample of elemental Si (hereinafter also referred to as "STD-Si"), and the dashed line shows the spectrum of a standard sample of SiO2 (hereinafter also referred to as "STD-SiO2"). Comparing the spectral peak shapes of STD-Si and STD-SiO2, the SiKβ1 peak is shifted to the longer wavelength side. Furthermore, the spectrum of STD-SiO2 includes the SiKβ1' peak, while the spectrum of STD-Si does not. EPMA100 can estimate the difference in the chemical bonding state of an unknown sample by determining which state of the standard sample in Figure 2 the unknown sample in which Si is detected is closer to.

[0033] [The Philosophy Behind This Disclosure] Next, the concept of the EPMA100 of this disclosure will be explained. There has been a long-standing desire to improve the accuracy of sample analysis using EPMA. Furthermore, when the above-mentioned state analysis mode or qualitative analysis mode is set, the EPMA100 generates a spectrum with a broad wavelength band for unknown samples. Therefore, since the spectroscopic crystal 61 and detector 63 are moved over long distances, the analysis time is often long. Generally, the spectral peaks that the EPMA100 uses to identify differences in chemical bonding states are often X-ray species with low spectral intensity. Therefore, to improve the accuracy of sample analysis, it is preferable for the EPMA100 to improve the signal-to-noise ratio (S / N) of the spectrum. To improve the S / N ratio of the spectrum, for example, it is preferable to slow down the movement speed of the spectrometer to increase the analysis time of the sample. However, slowing down the movement speed of the spectrometer increases the irradiation time of the electron beam to the sample, which may cause damage to the sample. In contrast, the EPMA100 of this disclosure improves the accuracy of sample analysis while reducing sample damage.

[0034] Figure 3 is a diagram illustrating the concept of this disclosure. In the example in Figure 3, the spectrum is constructed from the long wavelength side to the short wavelength side. In the example in Figure 3, the longest wavelength is λ6 and the shortest wavelength is λ1. Other wavelengths λ2, λ3, λ4, and λ5 are also shown. However, λ1 < λ2 < λ3 < λ4 < λ5 < λ6.

[0035] In the EPMA100 of this disclosure, the movement speed of the spectrometer 6 is set to high speed in wavelength bands that are not important for sample analysis. Conversely, the movement speed of the spectrometer 6 is set to low speed in wavelength bands that are important for sample analysis. In this embodiment, the low speed is also referred to as the "first speed". Furthermore, a medium speed faster than the low speed is also referred to as the "second speed", and a high speed faster than the medium speed is also referred to as the "third speed".

[0036] Generally, if the movement speed of the spectrometer 6 is increased, the analysis time of the sample S during the high-speed period can be shortened, but the signal-to-noise ratio (S / N ratio) of the spectrum based on the X-rays detected during that high-speed period will decrease. The reason for the decrease in the S / N ratio of the spectrum is, for example, that the counting period for the X-ray intensity is shortened. On the other hand, if the movement speed of the spectrometer 6 is decreased, the analysis time of the sample S during the high-speed period will be increased, but the S / N ratio (S / N ratio) of the spectrum based on the X-rays detected during that low-speed period will improve.

[0037] As described above, the control device 10 of the EPMA100 can change the movement speed of the spectrometer 6 while it is moving (during the analysis of the sample S). Therefore, the control device 10 slows down the movement speed of the spectrometer 6 during periods corresponding to wavelength bands of important parts of the spectrum, and speeds up the movement speed of the spectrometer 6 during periods corresponding to wavelength bands of less important parts of the spectrum. Speeding up the movement speed of the spectrometer 6 shortens the analysis time of the sample. Thus, it is possible to reduce damage to the sample due to X-ray irradiation while ensuring the accuracy of important wavelength bands of the spectrum. Note that the accuracy of the spectrum may decrease during periods corresponding to less important parts of the spectrum, but this has little effect on the accuracy of the sample analysis.

[0038] In the example shown in Figure 3, the first wavelength band, which is important for sample analysis, is the wavelength band where peak P occurs. The second wavelength band, which is the second most important for sample analysis, is the wavelength band at the base of peak P. The third wavelength band, which is not important for sample analysis, is the wavelength band that constitutes a flat region different from peak P. The period during which X-rays are detected to acquire the spectrum of the first wavelength band is also referred to as the "first period" shown in Figure 3. In other words, the first period is the period during which the spectrometer 6 moves at the first velocity (low velocity).

[0039] Furthermore, the period during which X-rays are detected to acquire the spectrum in the second wavelength band is also referred to as the "second period" as shown in Figure 3. In other words, the second period is the period during which the spectrometer 6 moves at the second velocity (medium velocity). Similarly, the period during which X-rays are detected to acquire the spectrum in the third wavelength band is also referred to as the "third period" as shown in Figure 3. In other words, the third period is the period during which the spectrometer 6 moves at the third velocity (high velocity).

[0040] With this configuration, the EPMA100 can move the spectrometer 6 faster than the first velocity during periods other than peak P, which is important in the analysis of the sample S, in order to improve accuracy at peak P of the spectrum. Therefore, the EPMA100 can improve accuracy at the peak portion of the spectrum while reducing damage to the sample S.

[0041] In the example in Figure 3, the first wavelength band is in the range of λ2 to λ5. Furthermore, in the example in Figure 3, the first wavelength band of the main body of peak P is in the range of λ3 to λ4. Since the spectrum in this wavelength band is of utmost importance, the movement speed of the spectrometer 6 during the period corresponding to this wavelength band is low speed (first speed). In addition, the second wavelength band, which is a part different from the main body of peak P (the tail portion of peak P), is in the range of λ2 to λ3 and λ4 to λ5. The movement speed of the spectrometer 6 during the period corresponding to this wavelength band is medium speed (second speed).

[0042] In the example shown in Figure 3, the third wavelength band is the range of λ1-λ2 and the range of λ5-λ6. Since the spectrum in this wavelength band is not important, the movement speed of the spectrometer 6 during the period corresponding to this wavelength band is high speed (third speed).

[0043] Figure 4 shows an example of another spectrum. The spectrum in Figure 4 includes a first peak P1 and a second peak P2. In the example in Figure 4, the period corresponding to the first peak P1 and the second peak P2 is referred to as the first period.

[0044] [Functional block diagram of the control unit] Figure 5 is a functional block diagram of the control device 10. In the example shown in Figure 5, the control device 10 includes an acquisition unit 102, a processing unit 104, a control unit 106, and a storage unit 108. As explained in Figure 1, the control device 10 is connected to a detector 63, an input device 13, a display device 14, and a drive mechanism 65.

[0045] The acquisition unit 102 acquires detection signals from the detector 63 and input information from the input device 13. The information acquired by the acquisition unit 102 is output to the processing unit 104. The processing unit 104 performs processing according to the information. The processing unit 104 uses information stored in the storage unit 108 as needed. The processing result by the processing unit 104 is output to the control unit 106. The control unit 106 performs processing according to the processing result. In this embodiment, the control unit 106 controls the drive mechanism 65 and the display device 14. For example, when the processing unit 104 specifies the first to third periods described above, it controls the drive mechanism 65 so that the movement speed corresponds to the first to third periods.

[0046] [mode] Next, the modes of this embodiment will be described. Users can select from various modes. Figure 6 is an example of the first mode screen. In this first mode screen, when the user performs a predetermined operation on the input device 13, the control unit 106 (see Figure 5) is displayed in the display area 14A of the display device 14.

[0047] In the example shown in Figure 6, there are three modes: sample type mode, pre-analysis mode, and no-pre-analysis mode. Furthermore, the pre-analysis mode includes a first pre-analysis mode, a second pre-analysis mode, and a third pre-analysis mode. Details of the modes will be described later.

[0048] When the user performs an operation on the input device 13 to specify the mode displayed on the first mode screen in Figure 6, the control unit 106 displays the second mode screen in the display area 14A. Figure 7 shows an example of the second mode screen. The second mode selection screen has a small-step mode and a large-step mode. The small-step mode is a mode that reduces the number of steps in the movement speed of the spectrometer 6. In the example in Figure 3, the number of steps is "3". The large-step mode is a mode with more steps than the small-step mode. In this embodiment, the number of steps in the small-step mode is "2", and the number of steps in the large-step mode is "3". A mode flag indicating the mode set by the user is stored in a predetermined memory area (for example, the RAM of the memory unit 108). The control device 10 can identify the mode set by the user by referring to the mode flag.

[0049] Next, we will explain the details of each mode in Figure 6. First, we will explain the sample type input mode. For example, a user may know the type of unknown sample to be analyzed, but wants to analyze the chemical bonding state of the target element contained in that unknown sample. Generally, the wavelength band in which spectral peaks appear is determined according to the type of unknown sample.

[0050] Therefore, at the EPMA100 stage, the manufacturer analyzes the sample type and the wavelength range of the spectral peak for that sample type. Furthermore, based on this wavelength range, the manufacturer determines the period during which the spectrometer 6 moves at a low speed (first period), the period during which the spectrometer 6 moves at a medium speed (second period), and the period during which the spectrometer 6 moves at a high speed (third period), and constructs a database. This database is also called the "first speed DB".

[0051] Figure 8 shows an example of the first velocity database. In this example of the first velocity database, each sample type is associated with a low-velocity wavelength band, a medium-velocity wavelength band, and a high-velocity wavelength band. For example, for sample S1, λ1 to λ2 is defined as the low-velocity wavelength band, λ2 to λ3 is defined as the medium-velocity wavelength band, and λ3 to λ4 is defined as the high-velocity wavelength band. As described above, the period corresponding to the low-velocity wavelength band corresponds to the "first period," the period corresponding to the medium-velocity wavelength band corresponds to the "second period," and the period corresponding to the high-velocity wavelength band corresponds to the "third period."

[0052] Note that the "..." in Figure 8 indicates that the description has been omitted. In other words, the first velocity DB is correspondence information in which the first period is associated with each sample type. The first velocity DB is stored in the storage unit 108 (memory).

[0053] When the user specifies the sample type input mode, the control unit 106 displays an input screen in the display area 14A that prompts the user to input the sample type. Figure 9 shows an example of the input screen. In the example in Figure 9, the text image "Please enter the sample type" and the input area 19 are displayed. When the user enters the type information indicating the sample type into the input area 19, the acquisition unit 102 accepts the user input of the sample type. The sample type is output to the processing unit 104. The processing unit 104 identifies the first to third periods associated with the user-inputted sample type based on (referencing) the first speed DB. In other words, the processing unit 104 identifies the periods corresponding to low speed, medium speed, and high speed, respectively. The identified information is output to the control unit 106.

[0054] The control unit 106 moves the spectrometer 6, reflecting the speed control of the spectrometer 6 based on the specified information, and performs the analysis. With this sample type input mode, the user can select the first period corresponding to the spectrum for which they want to improve accuracy by inputting the sample type, thereby improving user convenience.

[0055] Next, the first pre-analysis mode will be described. The first pre-analysis mode is a mode in which an X-ray is irradiated onto a target area of ​​the sample to generate a provisional spectrum, and the first period is automatically determined using the provisional spectrum. In this embodiment, the EPMA100 can perform both provisional analysis and main analysis. Main analysis is the analysis of the sample by generating a main spectrum. Provisional analysis is the generation of a provisional spectrum. The provisional spectrum is the spectrum used to identify the first to third periods in the main analysis. Furthermore, although the movement speed of the spectrometer 6 differs between the main analysis and the provisional analysis, the other processes are the same. That is, in the main analysis, X-rays are irradiated onto the target area of ​​the sample S, and in the provisional analysis, X-rays are also irradiated onto the target area of ​​the sample S. The target area is the area of ​​the sample S that the user wants to analyze.

[0056] In pre-analysis mode (automatic determination using a provisional spectrum), the EPMA100 generates a provisional spectrum by moving the spectrometer 6 at the third velocity (high speed) over the sample to be analyzed. As mentioned above, the spectrum generated by moving the spectrometer 6 at the third velocity (high speed) has a poor signal-to-noise ratio.

[0057] Figure 10 shows an example of a hypothetical spectrum. As shown in Figure 10, the signal-to-noise ratio (S / N ratio) of the hypothetical spectrum is poor. As mentioned above, although the movement speed of the spectrometer 6 differs between the actual analysis and the hypothetical analysis, the other processing is the same. Therefore, although the S / N ratio differs between the actual spectrum and the hypothetical spectrum, their shapes are similar. Thus, for example, the wavelength band of the peaks in the actual spectrum and the hypothetical spectrum are the same or nearly the same. In the example in Figure 10, the wavelength band λP is the peak of the hypothetical spectrum. Therefore, the control device 10 can estimate the wavelength band of the peak of the actual spectrum by analyzing the hypothetical spectrum. In the example in Figure 10, since the wavelength band of the peak of the hypothetical spectrum is the wavelength band λP, the control device 10 estimates (identifies) that the wavelength band of the peak of the actual spectrum is also the wavelength band λP. This allows the control device 10 to estimate the first to third periods. The control device 10 can automatically determine the first period corresponding to the spectrum for which accuracy needs to be improved based on the hypothetical spectrum. Furthermore, the control device 10 automatically determines the second and third periods by analyzing the pseudospectrum.

[0058] Conventional EPMA performs the main analysis with the spectrometer 6 moving at a constant speed. The analysis time in the "state analysis mode" or "qualitative analysis mode" of this conventional EPMA can be relatively long, sometimes 30 to 40 minutes. In contrast, in the pre-analysis mode, the control device 10 performs a high-speed preliminary analysis and the main analysis with speed change control. Therefore, compared to conventional EPMA, it is possible to improve the accuracy of sample analysis while reducing damage to the sample. In addition, since the control device 10 can generate a preliminary spectrum at the third speed (high speed), it can generate a preliminary spectrum in a shorter time compared to a configuration that generates a preliminary spectrum at the first speed.

[0059] Furthermore, the control device 10 may perform a predetermined correction process on the provisional spectrum. The correction process is, for example, a spectrum smoothing process. By performing such a correction process, the control device 10 can refine the provisional spectrum. Therefore, the control device 10 can improve the estimation accuracy of the wavelength band of the peaks in the actual spectrum (estimation accuracy for the first to third periods).

[0060] Next, the second pre-analysis mode will be explained. The second pre-analysis mode generates and displays a provisional spectrum, allowing the user to determine at least one of the first to third periods. In the second pre-analysis mode, the control device 10 displays the provisional spectrum (see Figure 10) in the display area 14A of the display device 14. The control device 10 then accepts user input for the peak period corresponding to the peak portion of the provisional spectrum. For example, the user can specify the portion of the displayed provisional spectrum corresponding to the peak period to the input device 13. This specified information is output from the input device 13 to the control device 10. In the pre-analysis mode (provisional spectrum display), the user can determine at least one of the first to third periods based on their visual perception of the provisional spectrum. Therefore, user convenience (degree of freedom) can be improved. The control device 10 determines the periods that were not determined by the user.

[0061] Next, the third pre-analysis mode will be explained. The third pre-analysis mode is a mode in which an electron beam is irradiated onto a location on the sample other than the target location to generate a provisional spectrum, and the first to third periods are automatically determined from this provisional spectrum. When the third pre-analysis mode is set, the control device 10 moves the sample stage 4 by controlling the sample stage drive unit 5. The control device 10 then irradiates a non-target location different from the target location by shifting the electron beam irradiation location of the sample S from the target location. Generally, in the sample S, the spectrum generated by irradiating the target location with an electron beam and the spectrum generated by irradiating the non-target location with an electron beam are the same or similar. Therefore, the control device 10 estimates the first to third periods of the actual spectrum based on the provisional spectrum generated by irradiating the non-target location with an electron beam.

[0062] Furthermore, in the third pre-analysis mode, the control device 10 generates a provisional spectrum by moving the spectrometer 6 at a first speed (low speed). Therefore, the control device 10 can generate a provisional spectrum with higher accuracy than when generating a provisional spectrum by moving the spectrometer 6 at a second speed.

[0063] In the third pre-analysis mode, a pseudospectrometry is generated by moving the spectrometer 6 at the first velocity (low velocity), resulting in the sample being irradiated with an electron beam for an extended period. However, the area irradiated with the electron beam is a non-target area. Therefore, damage to the non-target area may occur, but damage to the target area can be suppressed.

[0064] The third pre-analysis mode is effective when the main analysis is performed N times (N is an integer greater than or equal to 2) on the same sample S. The control device 10 generates a provisional spectrum in one preliminary analysis to identify the first to third periods. Therefore, since the control device 10 performs speed change control based on the first to third periods in the N main analyses, it can shorten the analysis time while ensuring accuracy compared to the case where speed change control is not performed in the N main analyses.

[0065] Next, the pre-analysis-free mode will be described. In the no-pre mode, without generating a provisional spectrum, during the present analysis, the first period to the third period are estimated. In the present embodiment, the control device 10 generates a spectrum by acquiring the intensity of the X-ray detected by the spectroscope 6 every predetermined period (for example, 0.375 seconds). While the spectroscope 6 is moving, the control device 10 specifies (estimates) which of the first period to the third period the current period is based on the intensity of the characteristic X-ray in the past during the movement.

[0066] Specifically, the control device 10 calculates the gradient of the spectrum being generated, and specifies the first period to the third period based on the gradient and the second speed DB. The gradient of the spectrum is calculated, for example, by the moving average of the intensity. The moving average is, for example, the average of the intensity acquired this time and a predetermined number of intensities in the immediate past in the spectrum being generated.

[0067] FIG. 11 is an example of the second speed DB. In the example of FIG. 11, as the range of the gradient absolute value m, a large range, a medium range, and a small range are defined. For example, the small range is defined as m1 ≦ m < m2. Also, the medium range is defined as m2 ≦ m < m3. Also, the large range is defined as m3 ≦ m. However, m1 < m2 < m3.

[0068] In the second speed DB, the third condition for the period (third period) in which the moving speed is the third speed is that the gradient absolute value m belongs to the small range. Also, the second condition for the period (second period) in which the moving speed is the second speed is that the gradient absolute value m belongs to the medium range. Also, the first condition for the period (first period) in which the moving speed is the first speed is that the gradient absolute value m belongs in the order of the large range, medium range, small range, large range, and medium range. Also, if necessary, the second medium range in this order may be omitted. The condition for the moving speed to switch from the first speed to the second speed is that the gradient absolute value m belongs from the large range to the medium range.

[0069] The control device 10 updates the absolute gradient value m (moving average value) each time it acquires X-ray intensity, and determines whether the updated absolute gradient value satisfies one of the first, second, or third conditions. The control device 10 then changes the movement speed of the spectrometer 6 according to the condition that was satisfied. Through this process, the EPMA 100 can perform speed change control without generating a false spectrum. Therefore, the EPMA 100 can ensure the accuracy of important parts of the spectrum while reducing damage to the sample without generating a false spectrum.

[0070] [Spectral normalization] Figure 12 shows a plot and the spectrum represented based on that plot. The faster the spectrometer 6 moves, the wider the spacing between plots becomes. Also, the slower the spectrometer 6 moves, the higher the X-ray intensity count value becomes. Therefore, the control device 10 normalizes (weights) the intensity to an appropriate value.

[0071] Specifically, the control device 10 reduces the X-ray intensity L1 detected in the first period based on the ratio of the first velocity V1 to the second velocity V2. The normalized intensity L1 is referred to as L1A. For example, the following equation (2) is performed.

[0072] Furthermore, the control device 10 reduces the X-ray intensity L2 detected in the second period based on the ratio of the second velocity V2 to the third velocity V3. The normalized intensity L2 is referred to as L2A. For example, the following equation (3) is performed. Also, V1 <V2<V3となる。 Strength L1A=L1×(V1 / V3) (2) Strength L2A=L2×(V2 / V3) (3) By performing such normalization, the control device 10 can suppress the increased X-ray intensity that occurs due to the slow travel speed. Note that other normalization methods may be used. For example, the weighting values ​​in equations (2) and (3) may be other values.

[0073] Furthermore, as described above, in this analysis, the control device 10 controls the speed change of the spectrometer 6 to generate this spectrum. Therefore, this speed change control may cause discontinuities in the spectral curve due to various factors. To address this, the control device 10 may perform correction processing (for example, smoothing) at several points around the discontinuous data before and after the change in the speed of the spectrometer 6. The control device 10 can generate a smooth spectral curve by applying such smoothing processing.

[0074] Furthermore, it is preferable that the EPMA100 performs speed change control in both the analysis of standard samples and the analysis of unknown samples. However, the EPMA100 may also perform speed change control in either the analysis of standard samples or the analysis of unknown samples.

[0075] [flowchart] Next, a flowchart illustrating the processing of the control device 10 will be described. Figure 13 is a flowchart of the processing of the control device 10 when the sample type input mode (see Figure 6) is set. Furthermore, when a predetermined start operation is performed by the user, the processing in Figure 13 and Figures 15 to 18 described later will begin. In step S12, the control device 10 determines whether or not a sample type has been entered from the input screen (see Figure 9).

[0076] The control device 10 waits until the sample type is entered (NO in step S12). Once the sample type is entered (YES in step S12), the control device 10 proceeds to step S14. In step S14, the control device 10 refers to the first velocity DB (see Figure 8) and determines the movement speed of the spectrometer 6 based on the sample type entered in step S12. In other words, in step S14, the control device 10 determines the first period, the second period, and the third period. To put it another way, in step S14, the control device 10 determines the timing of the change in movement speed.

[0077] Next, in step S16, the main analysis is performed. The main analysis generates the main spectrum. Next, in step S18, the main spectrum generated by the main analysis is subjected to a normalization process (see equations (2) and (3) above) and a smoothing process.

[0078] Figure 14 is a flowchart of the main analysis in step S16. In step S102, the control device 10 changes the movement speed of the spectrometer 6 at the timing determined in step S14. Then, in step S104, the control device 10 determines whether the main analysis is complete or not. If the main analysis is not complete (NO in step S104), the process returns to step S102. If the main analysis is completed in step S104, the process returns to step S18.

[0079] Figure 15 is a flowchart of the process of the control device 10 when the first pre-analysis mode (see Figure 6) is set. In step S22, the control device 10 moves the spectrometer 6 at the third speed (high speed) to generate a provisional spectrum (see Figure 10) (performs a provisional analysis). Next, in step S24, the control device 10 determines whether the provisional spectrum is complete or not. The control device 10 waits until the provisional spectrum is complete (NO in step S24). Then, when the provisional spectrum is complete (YES in step S24), in step S26, the control device 10 performs a smoothing process on the provisional spectrum. Note that the control device 10 does not have to perform this smoothing process.

[0080] Next, in step S28, the control device 10 determines the movement speed of the spectrometer 6 based on the generated pseudospectrum. In other words, in step S28, the control device 10 determines the first period, the second period, and the third period. In other words, in step S28, the control device 10 determines the timing for changing the movement speed. Next, the control device 10 executes the process of step S16.

[0081] Figure 16 is a flowchart of the processing of the control device 10 when the second pre-analysis mode (see Figure 6) is set. In step S32, following step S26, the control device 10 displays the provisional spectrum (see Figure 10) on the display device 14. Then, in step S34, the control device 10 determines whether or not a peak period corresponding to the peak portion of the provisional spectrum (the period corresponding to the wavelength band λP in Figure 10) has been input. The control device 10 waits until a peak period is input (NO in step S34). Once a peak period is input, the process proceeds to step S36. In step S36, the control device 10 determines the travel speed based on the peak period. Next, the control device 10 executes the process in step S16.

[0082] Figure 17 is a flowchart of the process of the control device 10 when the third pre-analysis mode (see Figure 6) is set. In step S42, the electron beam is irradiated onto a non-target area of ​​the sample S, and the spectrometer 6 is moved at the first velocity to create a provisional spectrum. Next, the control device 10 executes the process in step S24. The control device 10 may also display the provisional spectrum generated in step S42 on the display device 14 and prompt the user to input the first to third periods.

[0083] Figure 18 is a flowchart of the process of the control device 10 when the no-pre-analysis mode (see Figure 6) is set. As described above, when the no-pre-analysis mode (see Figure 6) is set, the control device 10 performs the main analysis while performing velocity change control without performing a preliminary analysis. In step S52, the control device 10 acquires the intensity of the X-rays detected by the spectrometer 6. Next, in step S54, the control device 10 calculates (updates) the spectral gradient by calculating the moving average of the intensity acquired in step S52 and a predetermined number of recent past intensities. Next, in step S56, the moving velocity is determined based on the spectral gradient and the second velocity DB (see Figure 11). Next, in step S58, the control device 10 determines whether the main analysis is complete or not. If the main analysis is not complete (NO in step S52), the process returns to step S52. If the main analysis is complete (YES in step S104), the control device 10 performs the process in step S18. The period from when the process in step S52 is executed until when the next step S52 is executed is the predetermined period mentioned above (for example, 0.375 seconds).

[0084] [Differentiation] (1) In the above-described embodiment, as explained in Figure 6, the EPMA 100 was configured to allow five users to select a mode. However, the EPMA 100 may be configured to allow at least two users to select a mode. Alternatively, the EPMA 100 may be configured to control only one of the five modes.

[0085] (2) The concept of this embodiment has been disclosed in an example applied to the EPMA100. However, the concept of this embodiment may be applied to other analytical instruments. Other analytical instruments include, for example, X-ray diffractometers (XRD).

[0086] (3) In this embodiment, the EPMA100 has been described in which the movement speed of the spectrometer 6 is slowed down for a period corresponding to the wavelength band of the peak, as shown in Figure 3 and the like. However, the EPMA100 may also be configured to speed up the movement speed of the spectrometer 6 for a period corresponding to the wavelength band of the peak. For example, the user may specify a peak that is not important in the sample analysis. Then, the EPMA100 speeds up the movement speed of the spectrometer 6 for a period corresponding to the wavelength band of that peak. Such a configuration can improve user convenience.

[0087] (4) In the multi-stage mode described above, a configuration in which the number of speed steps of the spectrometer 6 is specified has been explained. However, the multi-stage mode may also be a mode in which the number of speed steps of the spectrometer 6 is not specified, and the speed of the spectrometer 6 is changed continuously.

[0088] [Pattern] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following embodiments.

[0089] (Section 1) An X-ray analyzer according to one embodiment comprises a detection mechanism and a control device. The detection mechanism is a wavelength-dispersive detection mechanism configured to detect characteristic X-rays generated from a sample irradiated with an electron beam. The control device moves the detection mechanism. While moving the detection mechanism, the control device generates a spectrum of the sample based on the characteristic X-rays detected by the detection mechanism and changes the movement speed of the detection mechanism while it is moving.

[0090] With this configuration, the movement speed of the detection mechanism can be changed while it is moving. Therefore, for example, the movement speed of the detection mechanism can be slowed down during periods corresponding to wavelength bands of important parts of the spectrum, and accelerated during periods corresponding to wavelength bands of less important parts of the spectrum. Increasing the movement speed of the detection mechanism shortens the irradiation time of the electron beam onto the sample. Thus, it is possible to reduce damage to the sample caused by X-ray irradiation while ensuring accuracy of important parts of the spectrum.

[0091] (Clause 2) An X-ray analyzer as described in paragraph 1, wherein the control device moves the detection mechanism at a first velocity during a first period corresponding to the peak portion of the spectrum, and moves the detection mechanism at a second velocity faster than the first velocity during a second period different from the first period.

[0092] With this configuration, if accuracy at the peak portion of the spectrum is to be improved, the detection mechanism can be moved faster than the first velocity during periods other than the peak portion. This allows for improved accuracy at the peak portion of the spectrum while reducing damage to the sample.

[0093] (Clause 3) The X-ray analyzer described in paragraph 2, wherein the control device has a memory that stores correspondence information in which the first period is associated with each sample type. The control device receives user input of the sample type and identifies the first period associated with the user-inputted sample type based on the correspondence information.

[0094] This configuration allows the user to select the first period corresponding to the spectrum for which they want to improve accuracy, thereby enhancing user convenience.

[0095] (Clause 4) An X-ray analyzer as described in paragraph 2, wherein the control device generates a provisional spectrum of the sample and identifies a first period based on the provisional spectrum.

[0096] With this configuration, the first period corresponding to the spectrum for which accuracy needs to be improved can be automatically determined based on the provisional spectrum, thereby reducing the burden on the user.

[0097] (Clause 5) An X-ray analyzer as described in paragraph 2, wherein the control device generates a provisional spectrum of a sample, displays the provisional spectrum on a display device, accepts user input for peak periods corresponding to the peak portions of the provisional spectrum, and identifies a first period based on the peak periods.

[0098] With this configuration, the user can determine the first period based on the visual representation of the hypothetical spectrum. Therefore, user convenience can be improved.

[0099] (Item 6) An X-ray analyzer as described in Item 4 or 5, wherein the control device irradiates a target location of the sample with an electron beam and moves the detection mechanism at a second velocity to generate a provisional spectrum.

[0100] With this configuration, a provisional spectrum can be generated at a fast second velocity, allowing for the generation of a provisional spectrum in a shorter time compared to a configuration that generates a provisional spectrum at the first velocity.

[0101] (Clause 7) An X-ray analyzer as described in paragraph 4 or 5, wherein the control device irradiates a location on the sample different from the target location with an electron beam and moves the detection mechanism at a first velocity to generate a false spectrum.

[0102] With this configuration, a provisional spectrum can be generated at a slow first velocity, thus ensuring the accuracy of the provisional spectrum.

[0103] (Paragraph 8) An X-ray analyzer according to paragraph 6 or 7, wherein the control device corrects the provisional spectrum and identifies a first period based on the corrected provisional spectrum.

[0104] With this configuration, the false spectrum can be corrected, thus ensuring the accuracy of the false spectrum.

[0105] (Clause 9) An X-ray analyzer as described in paragraph 2, wherein the control device generates a spectrum by acquiring the intensity of characteristic X-rays detected by the detection mechanism at predetermined intervals, and identifies a first period during the movement of the detection mechanism based on the past intensity of characteristic X-rays during the movement.

[0106] This configuration allows for the generation of false spectra, while reducing damage to the sample and ensuring accuracy in key areas of the spectrum.

[0107] (Item 10) An X-ray analyzer according to any one of items 2 to 9, wherein the control device reduces the intensity of characteristic X-rays detected in the first period based on the ratio of the first velocity to the second velocity to generate a spectrum.

[0108] This configuration makes it possible to suppress the intensity that would otherwise increase due to the slow movement speed.

[0109] (Clause 11) An X-ray analyzer according to any one of Clauses 2 to 10, wherein the control device moves the detection mechanism at a third speed different from the first and second speeds, and sets either a first mode in which the detection mechanism moves at the first and second speeds, or a second mode in which the detection mechanism moves at the first, second, and third speeds, based on user input.

[0110] This configuration allows users to select the number of different movement speeds, thereby improving user convenience.

[0111] (Section 12) An X-ray analyzer as described in any one of Sections 1 to 11, wherein the detection mechanism has a wavelength-dispersive spectrometer configured to detect characteristic X-rays generated from a sample irradiated with an electron beam, and the X-ray analyzer is an electron probe microanalyzer.

[0112] With this configuration, it is possible to provide an electron probe microanalyzer to which the above technical concept is applied.

[0113] (Clause 13) A control method for an X-ray analyzer according to one embodiment, wherein the X-ray analyzer includes a wavelength-dispersive detection mechanism configured to detect characteristic X-rays generated from a sample irradiated with an electron beam. The control method includes generating a spectrum of the sample based on the characteristic X-rays detected by the detection mechanism while moving the detection mechanism. Generating the spectrum includes changing the movement speed of the detection mechanism while it is moving.

[0114] With this configuration, the movement speed of the detection mechanism can be changed while it is moving. Therefore, for example, the movement speed of the detection mechanism can be slowed down during periods corresponding to wavelength bands of important parts of the spectrum, and accelerated during periods corresponding to wavelength bands of less important parts of the spectrum. Increasing the movement speed of the detection mechanism shortens the irradiation time of the electron beam onto the sample. Thus, it is possible to reduce damage to the sample caused by X-ray irradiation while ensuring accuracy of important parts of the spectrum.

[0115] Furthermore, regarding the embodiments and modifications described above, it was intended from the outset that the configurations described in the embodiments could be appropriately combined, including combinations not mentioned in the specification, to the extent that no inconvenience or inconsistency arises.

[0116] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0117] 1 Electron gun, 2 Deflection coil, 3 Objective lens, 4 Sample stage, 5 Sample stage drive unit, 6 Spectrometer, 10 Control device, 12 Deflection coil control device, 13 Input device, 14 Display device, 14A Display area, 19 Input area, 61 Spectroscopic crystal, 63 Detector, 65 Drive mechanism, 100 EPMA, 102 Acquisition unit, 104 Processing unit, 106 Control unit, 108 Storage unit.

Claims

1. A wavelength-dispersive detection mechanism configured to detect characteristic X-rays generated from a sample irradiated with an electron beam, A control device that generates the spectrum of the sample based on the characteristic X-rays detected by the detection mechanism while moving the detection mechanism, The system includes a memory that stores correspondence information, in which a first period corresponding to the peak portion of the spectrum is associated with each sample type. The control device is The system accepts user input for sample type, Based on the correspondence information, the first period associated with the user-inputted sample type is identified. During the first period corresponding to the peak portion of the spectrum, the detection mechanism is moved at a first velocity. In a second period different from the first period, the detection mechanism is moved at a second speed that is faster than the first speed. An X-ray analyzer that generates the spectrum by reducing the intensity of the characteristic X-rays detected in the first period based on the ratio of the first velocity to the second velocity.

2. The control device is The detection mechanism is moved at a third speed different from the first and second speeds. The X-ray analyzer according to claim 1, wherein either a first mode in which the detection mechanism is moved at the first speed and the second speed, or a second mode in which the detection mechanism is moved at the first speed, the second speed, and the third speed, is set based on user input.

3. The detection mechanism includes a wavelength-dispersive spectrometer configured to detect characteristic X-rays generated from a sample irradiated with the electron beam. The X-ray analyzer according to claim 1 or claim 2, wherein the X-ray analyzer is an electron probe microanalyzer.

4. In a control method for an X-ray analyzer, The X-ray analyzer is equipped with a wavelength-dispersive detection mechanism configured to detect characteristic X-rays generated from a sample irradiated with an electron beam. The control method comprises moving the detection mechanism and generating a spectrum of the sample based on the characteristic X-rays detected by the detection mechanism, To generate the spectrum of the aforementioned sample, Accepting user input of sample type, Based on correspondence information in which the first period corresponding to the peak portion of the spectrum is associated with each sample type, the first period associated with the user-inputted sample type is identified. In the first period corresponding to the peak portion of the spectrum, the detection mechanism is moved at a first velocity. In a second period different from the first period, the detection mechanism is moved at a second speed that is faster than the first speed. A control method for an X-ray analyzer, comprising reducing the intensity of the characteristic X-rays detected in the first period based on the ratio of a first velocity to a second velocity to generate the spectrum.

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