JPH01314988A - Plasma electron temperature measuring apparatus - Google Patents

Abstract

PURPOSE:To enable reduction in cost with the miniaturization of an X-ray detection part by providing an X-ray detector combined with a plurality of multiple kinds of filters different in the attenuation rate of X rays in vicinity to a sampling point. CONSTITUTION:X rays 2 released from a plasma 1 are divided into larger areas with a slit 3 and filters 51 are arranged corresponding to smaller areas to split the larger areas into three smaller areas. Here, filters 51 with respective transmittances are laminated to form parts having areas different in transmittance so that the X rays are attenuated by three stages to detect signals in terms of different attenuation rates with a multi-channel detector 16. After amplified 7, necessary signals are selected with a multiplexer 12 and converted 8 into digital from analog to be inputted into a computer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a measuring device that measures X-rays from plasma and measures plasma electron temperature.

[Prior Art] As a method of measuring the temperature of plasma, there is a method of measuring X-rays emitted from plasma.

This method utilizes the fact that there is a correlation between plasma temperature and X-ray intensity emitted from the plasma, and the Xfi intensity is measured and the electron temperature of the plasma is determined from the intensity ratio.

A conventional technique is shown in FIG. 6 and will be explained.

When measuring Xti from plasma, it is difficult to cover the energy band required for measurement with one xi detector. Therefore, measurements are performed by using a type of X-ray detector and passing the incident X-rays through a filter depending on the intensity.

For this reason, conventional X-ray detectors have been provided with a function to replace a large number of filters depending on the X-ray intensity of interest or as needed.

FIG. 6 shows a plasma electron temperature measuring device having this filter exchange function. In this figure, X-rays (2) emitted from plasma (1) are narrowed down by a slit (3).

The X-rays that passed through the slit (3) are transferred to a filter exchanger (4).
After being attenuated when passing through the filter (5), it is detected by the X-ray detector (6).

This detection result is amplified by an amplifier (7), then converted into a digital signal by an A-D converter (8), and input to a computer (9) for processing.

The filter (5) attenuates the intensity of the X-rays incident on the X-ray detector (6), but when X-rays with a wide energy range are processed by the same detector and the same amplifier, the intensity of the X-rays decreases. must be within a range determined by the characteristics of the detector. However, the actual X-ray intensity rarely falls within this range. Therefore, even if the X-ray intensity is outside the range, it is detected after being attenuated so that it falls within the range.

In Fig. 6, two types of filters (5) are prepared, and by switching and replacing them with a filter exchanger (4),
Attenuate the line.

The filter exchanger (4) in this example is of a sliding type, and two types of filters (5) are integrated so as to be adjacent to each other. It is possible to attenuate the X-rays by switching the arrangement.

Regarding this filter (5) and X-ray detector (6),
As shown in the figure, for miniaturization, a multi-channel detector (61) is used and a large number of filters (51) each having a different degree of attenuation have been devised.

[Problems to be Solved by the Invention] When a filter exchanger (4) is provided for one X-ray detector as in the past, it is difficult to increase the size of the device. Accordingly, the filter exchanger (4) must also become larger, which promotes an increase in the overall size.

Furthermore, if a filter and an X-ray detector are used as an X-ray detection section, in order to make this X-ray detection section compact, multiple types of filters (51) are always provided, and the X-rays passing through each of these filters (51) are There is also a device equipped with a multi-channel detector (61) for detection, as shown in FIG.

The filter (51) in FIG. 5 has a three-stage structure, with the first stage of the filter being the easiest for X-rays to pass through, and the third stage being the most difficult for X-rays to pass through. A multi-channel detector (61) detects the X-rays that have passed through each of the first, second, and third stages.

Filter (5) and filter exchanger (4) shown in Figure 6
A combination of a multi-stage filter (51) and a multi-channel detector (61) shown in FIG. 5 is a compact integration of the X-ray detector (6).

The X-ray detection section shown in Fig. 5 has a filter exchanger (4) and an X-ray detector (6) in the conventional example shown in Fig. 6.
This corresponds to a combination of units, but in the configuration shown in FIG. 6, there is one detection signal per set. On the other hand, three detection signals are output from the X-ray detection section shown in FIG. For this reason, each signal was amplified and converted into a digital signal, making the device large and expensive. That is, in a device having the same number of sampling points as the embodiment shown in FIG. 6, the device having the X-ray detection section shown in FIG.
Must be equipped with a D converter.

This is disadvantageous in terms of cost, especially considering that the A-D converter is expensive.

The present invention solves the above-mentioned problems of large size and high cost.
The purpose is to solve the problem.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, an X-ray detector combined with a plurality of types of filters having different X-ray attenuation rates is provided adjacent to a sampling point. The signals detected by these X-ray detectors are regarded as signals due to X-rays in the same region.

After amplifying the signals obtained by detecting multiple X-rays in the same region with different attenuation factors using an amplifier, only the necessary signals are selected by the signal selection means, and the selected signals are sent to the A-D converter. convert it into a digital signal.

The amplifier is provided before the signal selection means,
By providing it at a later stage, the number of amplifiers installed can be reduced in the same way as the A-D converter.

Furthermore, in addition to selecting a plurality of signals from the same area, signals from a plurality of areas may be selected.

[Function] With the above configuration, in the present invention, when X-rays of a certain intensity are incident, the X-rays that have passed through a plurality of filters are detected by a multi-channel detector, and a signal is output from each channel. That is, this signal is an X-ray signal that has been attenuated by a filter, and a signal selection means selects from among these signals a signal that meets the conditions of the amplifier, etc. being used.

The signal selected here is amplified by an amplifier and then
A converter converts it into a digital signal.

[Example] A first example of the present invention will be described with reference to FIG. In the embodiment of FIG. 1, the X-rays (2) emitted from the plasma (1) are squeezed out by the slit (3).

In this embodiment, the X-rays after passing through the slit (3) are divided into large regions, and each celestial region is further divided into three small regions. Here, a filter (51) for attenuating X-rays in three stages is provided corresponding to each small area, and detection is performed for each gradation. This large area has densely set licks and slits (3)
The distribution of X-rays after passing through can be measured.

The X-rays transmitted through this filter (51) are detected by a multi-channel detector (61), and the filter (51) is provided on the detection surface of this multi-channel detector (61). In this example, a filter with a certain transmittance (5
1) to create areas with different transmittances by superimposing them, and use multi-channel detectors (61
) is used to extract the output of

The signal output from each multi-channel detector (61) is amplified by an amplifier (7) and then a multiplexer (12).
) is input. The signals input to the same multiplexer (12) are the outputs of adjacent and different filters. A multiplexer (12) selects only the necessary outputs from these outputs.

The signal output from the multiplexer (12) in this manner is converted into a digital signal by the AD converter (8), and then input to the computer (13).

In FIG. 1, the measurement range is subdivided, a plurality of filters are provided for each part, and the state of X-rays in each part is measured. For this reason, the types of filters are limited.

FIG. 2 shows a second embodiment in which the number of filters is increased.

In the above embodiment, the X-rays passing through the slit (3) are divided into a plurality of regions, and the X-rays in these regions are filtered (51).
It was designed to attenuate in three stages. Therefore, the X-rays are attenuated in three steps for each region.

On the other hand, in this embodiment, the X that passed through the slit (3)
A filter that attenuates into multiple levels without dividing the line (51)
It allows the information to pass through. In the first embodiment, the distribution of X-rays can be measured, but data can only be taken up to three gradations in each region. Although this embodiment can provide a large number of gradations, it requires a large area, which is disadvantageous when examining the distribution of X-rays.

A third embodiment of the present invention is shown in FIG. 3 and will be described.

This embodiment integrates a multichannel detector (61), a multiplexer (12), and an amplifier (7). According to this embodiment, a multi-channel detector (61
), multiplexer (12), and amplifier (7) are integrated and miniaturized, as well as a multi-channel detector (61).
The 31@ order through which the signal passes is the multi-channel detector (6
1) → multiplexer (12) → amplifier (7), so only the signal after selection needs to be amplified, and amplifier (7)
) can be reduced.

A fourth embodiment of the present invention is shown in FIG. 4 and will be described.

In this embodiment, a multiplexer (12) is used to connect multiple amplifiers (7
) is switched and outputted from Jl[, and the timing of this switching and the timing of loading into the A-D converter (8) are determined by the timing generator (13).

In this way, by performing A-D conversion of the signal using a time-division method, the sampling rate of each channel decreases, but
It becomes possible to further reduce the number of AD converters.

[Effect of the invention] According to the present invention, it is possible to eliminate the filter exchanger and downsize the X-ray detector, and even when the number of detection points of the X-ray detector is increased, the A-D converter Also, since there is no need to increase the number of amplifiers, the same effect as cost reduction can be obtained.

In other words, by making the X-ray detection part smaller and reducing costs, it is possible to increase the packaging density of the X-ray detector,
The spatial resolution of plasma electron temperature measurement can be improved. Further, miniaturization of the X-ray detector also means miniaturization of the vacuum container that covers it, and as the vacuum container is miniaturized, the evacuation device may also be made smaller. This means that in the reality that this device has many restrictions on installation space, it is now possible to install it in places where it was previously impossible to install it.
The benefits are great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram explaining the first embodiment of the present invention, FIG. 2 is a block diagram explaining the second embodiment of the present invention, and FIG. 3 is a block diagram of the detection part in the third embodiment of the present invention. 4 is a signal transmission path diagram in the fourth embodiment of the present invention, FIG. 5 is a block diagram of a detection section explaining a conventional technique using a multi-channel detector (61), and FIG. 6 is a conventional FIG. 2 is a block diagram of the overall configuration for explaining the technology of FIG. 1...Plasma 2...X-ray 3...Slit 4...Filter exchanger 5.51 ......Filter 6...X-ray detector 61...Multi-channel detector 7...
......Amplifier 8...A-D converter 9...Computer 12...Multiplexer 13...・
・・・・Timing generator agent Patent attorney Nori Chika Noribu Sanno - Figure 1 Figure 2. f Yo 3 gigantic and -51 filter Fig. 5 -) -m- Shi - - m- (-1157/ -M- □-te- □-) -1 6 Fig. 11 Plasma 1 2 X-ray 3 Slit - 5 filter - 5 filter 4 filter exchanger - 6 X-ray detector - 6 X-ray detector - 7 amplifier - 8 A-D converter - 9 computer

Claims (2)

[Claims] (1) In order to measure the X-ray intensity, the measurement target area is divided into multiple areas, multiple types of filters are provided in each area that attenuate the X-rays at different attenuation rates, and the X-rays that pass through the filters are provided. a plurality of multi-channel detectors for detecting, a plurality of amplifiers for amplifying the outputs of these multi-channel detectors, a signal selection means for selecting and outputting only a specific output from the outputs of these amplifiers, and a signal selection means for selecting and outputting only a specific output from the outputs of these amplifiers; A- converting the signal selected by the selection means into a digital signal;
A plasma electron temperature measuring device comprising: a D converter; (2) In order to measure X-ray intensity, the measurement target area is divided into multiple regions, and multiple multi-channel detectors each equipped with multiple types of filters that attenuate X-rays at different attenuation rates, and these multi-channel detectors are used. A signal selection means for selecting and outputting only a specific output from the outputs of the channel detector, an amplifier for amplifying the signal selected by the signal selection means, and an A-D converter for converting the output of the amplifier into a digital signal. A plasma electron temperature measuring device comprising: