JPH0980002A - Method for measuring intensity of x ray diffraction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the intensity of X ray diffraction with high accuracy without saturating a photodiode by calculating real currents by eliminating dark currents from actual currents measured by a plurality of times and integrating the real current values. SOLUTION: The electric current corresponding to the quantity of incident X rays flows to a photodiode array 1 and the current is stored in a capacitor. The stored current is sent to an amplifier 2 at regular time intervals and amplified voltages are read by means of a data processing unit 3 and outputted to a controller 4. Firstly, dark currents flowing to the array 1 are measured while a sample is not irradiated with X rays and the measured values are stored in the memory of the controller 4. Then the sample is irradiated with X rays and the array 1 measures actual currents by receiving diffracted X rays coming out from the sample and stores the measured actual current values in the memory of the controller 4. The controller 4 calculates real currents by removing the dark currents from the actual currents measured by a plurality of time and finds the intensity of the diffracted X rays by integrating the real currents calculated at every measuring time unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray diffraction intensity measuring method for measuring the intensity of diffracted X-rays emitted from a sample in an X-ray diffraction measurement.

[0002]

2. Description of the Related Art X-ray diffraction measurement is carried out by measuring the diffracted X-rays emitted from the sample with an X-ray measuring instrument when the sample is irradiated with X-rays, and measuring the X-ray diffraction intensity based on the measurement result. Analyze the structure of crystal samples. Proportional counters, scintillation counters, and the like are known as X-ray measuring devices used for such X-ray diffraction measurement, but in recent years, an X-ray diffractometer using a photodiode array as an X-ray measuring device has been developed. , X-ray diffraction intensity has been improved.

FIG. 4 is a flow chart for explaining a method for measuring X-ray diffraction intensity using a conventional photodiode array. As shown in the figure, this type of conventional X
In the method of measuring the line diffraction intensity, the dark current flowing in the photodiode is measured (S21), and then the current (actual current) flowing in the photodiode in the X-ray diffraction measurement is measured (S22). The real current includes a dark current flowing through the photodiode due to the influence of ambient temperature and the like in addition to the true current generated by the incidence of the diffracted X-rays. This real current is continuously measured for a fixed time, and then the dark current for the measurement time is removed from the real current to calculate the true current generated by the incidence of the diffracted X-rays (S23). The X-ray diffraction intensity was calculated based on the measurement result (S24).

[0004]

It is known that the dark current flowing through the photodiode exponentially increases as the temperature rises. However, the current capacity that can be accumulated in the photodiode is naturally limited, and when X-ray diffraction measurement is continuously performed for a long time, if the ambient temperature rises during that time, the photodiode will be affected by dark current. There is a possibility that the true current due to the incidence of the diffracted X-rays becomes unmeasurable due to the saturated state.

Therefore, conventionally, measures such as shortening the measurement time have been taken, but when the measurement time is shortened, there is a problem that the peak value indicating the true current is not clearly displayed and the measurement accuracy is lowered. there were. The present invention has been made to solve such a problem, and an object thereof is to realize a highly accurate X-ray diffraction intensity measurement without the risk of saturating the photodiode.

[0006]

In order to achieve the above object, the present invention is an X-ray diffraction intensity measurement in which the intensity of diffracted X-rays emitted from a sample is measured using a photodiode array in X-ray diffraction measurement. In the method, a dark current measuring step of measuring a dark current flowing through the photodiode, a real current measuring step of measuring a real current flowing through the photodiode in the X-ray diffraction measurement, and a dark current being removed from the measured real current. , A true current calculation step of calculating a true current generated in the photodiode due to the incidence of the diffracted X-rays.

The actual current measuring step is divided into a plurality of times, and the true current is calculated through the true current calculating step for each real current measured at each measuring time.
In addition, the true current calculated in each measurement time unit is integrated, and the intensity of the diffracted X-ray is obtained from the integrated data of the true current.

In the present invention, since the actual current measuring step is divided into a plurality of times as described above, each measuring time is short and the photodiode can be reset before being saturated. Moreover, since the peak value of the current can be clarified by integrating the true current calculated in each measurement time unit, highly accurate X-ray diffraction intensity data can be obtained.

Further, according to the present invention, the X-ray diffraction intensity is calculated from the true current calculated in each measurement time unit, and the X-ray diffraction intensity obtained in each measurement time unit is integrated to obtain a high X-ray diffraction intensity. It is possible to improve accuracy.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of an X-ray detection device used for measuring the X-ray diffraction intensity of the present invention. First, the outline of the X-ray measuring apparatus will be described with reference to the same figure.

The X-ray detection device shown in the figure comprises a photodiode array (PSD detector) 1 and an amplifier (AMP).
2, a data processing unit 3 and a control device 4. The photodiode array 1 is a kind of line sensor formed of a large number of photodiodes, and an electric current flows according to the incident X-ray dose. A current (dark current) flows through the photodiode irrespective of the incidence of X-rays due to the influence of ambient temperature or the like. The current flowing in the photodiode in this way is accumulated in the capacitor connected to the photodiode. Saturation of the photodiode means that the amount of accumulated current in this capacitor is full.

The current stored in the capacitor is sent to the amplifier 2 at regular intervals. The amplifier 2 converts the input current value into a voltage and amplifies it. The data processing unit 3 is
The amplified voltage is read and output to the control device 4 as a current measurement signal. The control device 4 includes the data processing unit 3
A plurality of memories are provided for individually storing the current measurement signal sent from the device for each of a dark current measurement step, an actual current measurement step, and a true current calculation step, which will be described later. The control device 4 also includes a central processing unit (CPU) that executes control commands for the photodiode array 1 and the data processing unit 3 and arithmetic processing of each data.

The X-ray diffraction intensity measuring method according to the embodiment of the present invention is for measuring the intensity of the diffracted X-rays emitted from the sample during the X-ray diffraction measurement. Therefore, the measurement method is carried out in a series of X-ray diffraction measurements. Therefore, first, the outline of the X-ray diffraction measurement will be described. The X-ray diffraction measurement is performed using an X-ray diffractometer composed of an X-ray source, a goniometer, a sample stage, and the above-mentioned components such as the X-ray detector. The sample to be measured is mounted on the sample mounting portion provided at the center of rotation of the goniometer. When the sample is irradiated with X-rays from the X-ray source, diffracted X-rays are emitted from the sample in a predetermined direction according to the crystal structure.

Thus, the direction of the diffracted X-rays emitted from the sample is detected by the goniometer and the X-ray diffraction intensity is measured by the X-ray detector. The goniometer also detects the orientation of the sample with respect to the incident X-ray. Angle detection data and X by these goniometers
Based on the X-ray diffraction intensity data measured by the line detector,
The crystal structure of the sample will be analyzed.

FIG. 2 is a flow chart for explaining the method for measuring the X-ray diffraction intensity according to the embodiment of the present invention. Next, an embodiment of the method for measuring the X-ray diffraction intensity will be described in detail with reference to FIG. This X-ray diffraction intensity measuring method includes a dark current measuring step, an actual current measuring step, and a true current calculating step.

First, in the dark current measuring step (S1 in the same figure), the current flowing through the photodiode is measured without irradiating the sample with X-rays. At this time, no diffracted X-ray is emitted from the sample, and therefore the current flowing through the photodiode is only the dark current due to the influence of the ambient temperature and the like. The dark current measurement time can be set arbitrarily within the range where the photodiode is not saturated. It is also possible to measure the dark current any number of times and use the average value thereof as the dark current data.

In FIG. 2, the dark current measuring step is shown in the first step (S1) in the X-ray diffraction intensity measurement.
This step may be inserted after the actual current measuring step described below, or may be inserted before or after each actual current measuring step. When the ambient temperature may change before the end of the X-ray diffraction intensity measurement, the dark current value also changes with the temperature change. Therefore, this dark current measurement step is also performed every time the actual current measurement step is performed. Is preferred. The measured dark current is stored in the memory in the control device 4 as a dark current measurement signal.

Next, in the actual current measurement step (S2 in FIG. 2), the sample is irradiated with X-rays and the diffracted X-rays emitted from the sample are received by the photodiode, and the current (actual current) flowing through the photodiode at this time. To measure. Diffraction X for real current
The current (true current) generated by the incidence of the line and the dark current flowing due to the influence of the ambient temperature are included. The measurement time of this actual current can be arbitrarily set within the range where the photodiode is not saturated. And the measured actual current is
The actual current measurement signal is stored in the memory in the control device 4.

After that, the process proceeds to the true current calculation step (S3 in FIG. 2), and the true current generated in the photodiode due to the incidence of the diffracted X-ray is calculated. That is, since the actual current measured previously includes the true current and the dark current, the true current can be calculated by removing the dark current from the actual current. The true current calculation step is automatically processed in the control device 4, and the calculation result (true current data) is stored in the memory.

Then, returning to the actual current measuring step (S4),
The current (actual current) flowing through the photodiode is measured again for an arbitrary measurement time (S2). Then, through the true current calculation step (S3), the true current generated in the photodiode due to the incidence of the diffracted X-rays is calculated and integrated with the previously stored true current data.

The actual current measurement is repeated for a predetermined target time, the true current data obtained at each measurement time is accumulated, and after the accumulated data for the target time is obtained,
The X-ray diffraction intensity is calculated based on this integrated data (S
5). Although the peak value is not clear in the true current data for each measurement time, the peak value of the true current can be clearly displayed by integrating the peak value. Therefore, the error can be calculated by calculating the X-ray diffraction intensity from this integrated data. It is possible to obtain an X-ray diffraction intensity with a small amount. The X-ray diffraction intensity calculated in this way is stored in the memory in the control device, and the measurement of the X-ray diffraction intensity is completed.

FIG. 3 shows an X according to another embodiment of the present invention.
It is a flow chart which shows a measuring method of line diffraction intensity. In this embodiment, after the dark current measuring step (S11) is completed, the actual current measuring step (S12) and the true current calculating step (S1).
3) is performed in arbitrary measurement time units, and X is continuously measured.
After the line diffraction intensity is calculated (S14) and the intensity data is stored in the memory, the process returns to the actual current measuring step (S12) again.

That is, the X-ray diffraction intensity data is calculated for each measurement time and stored in the memory, and this is repeated until a predetermined target time is reached, and the sequentially calculated X-ray diffraction intensity data is integrated. Also by accumulating the X-ray diffraction intensity data in this way, the peak value of the X-ray diffraction intensity becomes clear and a highly accurate measurement result can be obtained.
Also in this embodiment, the dark current measuring step may be inserted after the actual current measuring step, or may be inserted before or after each actual current measuring step.

[0024]

As described above, according to the present invention,
Since the actual current measurement process is performed by dividing it into multiple times,
Each measurement time is short, and it is possible to prevent the photodiode from being saturated. Moreover, by accumulating the true current calculated in each measurement time unit or the X-ray diffraction intensity obtained based on the true current, highly accurate X-ray diffraction intensity data with a clear peak value is obtained. be able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of an X-ray detection device used for X-ray diffraction intensity measurement of the present invention.

FIG. 2 is a flowchart for explaining a method for measuring X-ray diffraction intensity according to the embodiment of the present invention.

FIG. 3 is a flowchart for explaining an X-ray diffraction intensity measuring method according to another embodiment of the present invention.

FIG. 4 is a flow chart for explaining a method for measuring X-ray diffraction intensity using a conventional photodiode array.

[Explanation of symbols]

 1: Photodiode array 2: Amplifier 3: Data processing unit 4: Control device

Claims (2)

[Claims] 1. An X-ray diffraction intensity measuring method for measuring the intensity of diffracted X-rays emitted from a sample using a photodiode array in X-ray diffraction measurement. Dark current measurement for measuring dark current flowing in the photodiode. Step, an actual current measurement step of measuring an actual current flowing through the photodiode in the X-ray diffraction measurement, and removing the dark current from the actual current to obtain a true current generated in the photodiode due to incidence of diffracted X-rays. And a true current calculation step of calculating a current, while performing the real current measurement step divided into a plurality of times, the true current through the true current calculation step for each real current measured at each measurement time Measurement of X-ray diffraction intensity, which is characterized in that the true current calculated and integrated in each measurement time unit is integrated, and the X-ray diffraction intensity is obtained from the integrated data of the true current. Law. 2. An X-ray diffraction intensity measuring method for measuring the intensity of diffracted X-rays emitted from a sample using a photodiode array in the X-ray diffraction measurement. Dark current measurement for measuring a dark current flowing in the photodiode. Step, an actual current measurement step of measuring an actual current flowing through the photodiode in the X-ray diffraction measurement, and removing the dark current from the actual current to obtain a true current generated in the photodiode due to incidence of diffracted X-rays. And a true current calculation step of calculating a current, while performing the real current measurement step divided into a plurality of times, the true current through the true current calculation step for each real current measured at each measurement time Calculate and obtain the X-ray diffraction intensity,
A method for measuring X-ray diffraction intensity, which is characterized by integrating the X-ray diffraction intensity obtained in each measurement time unit.