JPH0452548A - Plasma measuring apparatus - Google Patents

Abstract

PURPOSE:To realize remarkable saving of costs by providing a movable slit for alignment which allows only a part of an image of the scattering light to pass in front of an incident end face of a bundle of optical fibers. CONSTITUTION:Laser lights 2 scattered by a plasma 1 to be measured from monitoring points A-F 3-8 are condensed at 9. The laser lights 2 are guided by a bundle of optical fibers A-F 11-16 which are arranged at an image forming face 10 in a manner corresponding to respective incident end faces 17-22. The spectrum of the lights obtained at 23 is converted to an electric signal by a photodetector 24, so that the plasma 1 is measured. At this time, there are movable slits 25, 32 in front of the outermost fibers A11 and F16 of the image forming surface 10. These slits 25, 32 have slits 26, 41 for detecting a formed image at all of the end faces, right slits 27, 42 for detecting a formed image at the right half of all the end faces, and left slits 28, 43 for detecting a formed image at the left half of all the end faces. Alignment is performed in this structure.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a plasma measurement device, and in particular, to a plasma measurement device that uses a bundled optical fiber array to detect scattered light from multiple points of plasma generated in a tokamak-type nuclear fusion device. Guide to spectrometer 9
The present invention relates to a plasma measurement device that measures plasma by detecting a spectrum separated by a spectrometer using a photodetector.

[Conventional technology]

A conventional technique will be explained with reference to the drawings. FIG. 2 is a configuration diagram of a conventional plasma measurement device.

In FIG. 2, 1 is the plasma to be measured.

2 is a laser beam that is scattered by the plasma 1; 3
- 8 are observation points A to F, respectively, and the laser light 2 scattered from these positions is focused by a condensing lens 9 and formed into an image on an imaging plane 10 . The bundle optical fibers A-F input end surfaces 17-22 of the bundle optical fibers A-Fil-17 are installed on the imaging plane IO, and the observation points A-F3-
The laser beam 2 scattered from the laser beam 2 is guided to the spectrometer 23, and the spectrum is separated by the spectrometer 23, and the spectrum is converted into an electric signal by the photodetector 24.

At this time, the positions of the observation points B to E4 to E7 and the position through which the laser beam 2 passes must match.

To perform this alignment, the bundle optical fiber A
ll and F16 are each divided into two parts, such as the bundle optical fiber A input end face 17 and the bundle optical fiber F input end face 22. Alignment A Furukawa end face 37 becomes photodetector A useful 33.

The end face 38 for alignment A left is attached to photodetector A right 34,
In addition, the alignment F right end surface 39 is a photodetector F Ishikawa 35.
, the alignment F left end face 40 is the photodetector F surface face 36.
These are the incident ends for guiding scattered light to the respective ends.

The laser beam is adjusted so that the output signal of the photodetector A useful 33, the output signal of the photodetector A right 36, the output signal of the photodetector F Ishikawa 35, and the output signal of the photodetector F surface 36 are equal to each other. By adjusting the position of 2, observation points A-F
The positions 3 to 8 and the position through which the laser beam 2 passes were set.

[Problem to be solved by the invention]

The conventional plasma measurement device described above requires two dedicated bundle optical fibers for alignment.
In addition, four dedicated photodetectors are required for alignment, which has the disadvantage of increasing costs.

[Means to solve the problem]

The device of the present invention includes a condenser lens for condensing scattered light of a laser from a plurality of observation points of plasma generated in a tokamak-type nuclear fusion device onto an imaging plane; A plurality of bundled optical fibers are used to guide scattered light from plasma to a spectrometer, a spectrometer is used to separate the scattered light that is not guided by the bundled optical fibers, and the spectrum separated by the spectrometer is converted into an electrical signal. In the plasma measurement device that measures plasma, the plasma measurement device includes a photodetector for converting the plasma into an incident end face of two bundled optical fibers arranged at the outermost side of the image forming plane among the plurality of bundled optical fibers. 1. A fully open slit that receives the image formed by the scattered light on all of the input end faces of the two bundle optical fibers when performing normal plasma measurement, and a fully open slit that receives the image formed by the scattered light on all of the incident end faces of the two bundle optical fibers when performing normal plasma measurement, and a fully open slit that receives the image formed by the scattered light on all of the input end faces of the two bundle optical fibers when performing normal plasma measurement. A Furukawa slit and a cloth layer slit are provided on the right half and the left half of the incident end face of the bundle optical fiber to receive the image formed by the scattered light.

Furthermore, the apparatus of the present invention has a configuration in which the plurality of observation points are set on the optical path of laser light that is irradiated onto the plasma and scattered.

〔Example〕

Next, one embodiment of the present invention will be explained with reference to the drawings.

FIG. 1 is a configuration diagram of an embodiment of a plasma measuring device according to the present invention.

1 is the plasma to be measured, and 2 is a laser beam that is scattered by the plasma 1. Laser beams 2 scattered from the positions of observation points A-F3 to A-F8 are condensed by a condensing lens 9 and formed into an image on an imaging plane 1o. Bundle optical fibers A to Fll to 16 are installed on the imaging plane 10 like bundle optical fibers A to F input end faces 17 to 22, and observation points A to F3 to
The laser beam 2 scattered by the laser beam 2 is guided to a spectroscope 23, and a photodetector 24 converts the spectrum into an electrical signal.

At this time, the positions of the observation points A to F3 to F8 and the position through which the laser beam 2 passes must match. In order to perform this alignment, a movable slit (1) 25 and a movable slit (2) 32 are installed in front of the bundle optical fiber All and the bundle optical fiber F16.

When performing normal measurement, the reference (1) 29 of the movable slit (1) 25 is aligned with the center of the bundle optical fiber A input end face 17. As a result, the fully open slit 26 of the movable slit (1) 25 is brought into alignment with the incident end surface 17 of the bundle optical fiber A.

Similarly, the reference (1) 36 of the movable slit (2) 32
is aligned with the center of the input end face 22 of the bundle optical fiber F. As a result, the fully open slit 4 of the movable slit (2) 32
1 is aligned with the input end face 22 of the bundle optical fiber F. As described above, the scattered light condensed by the condenser lens 9 enters the bundle optical fibers A11 and F16 without being hindered.

When performing alignment, moveable slits (1), 2
5 criteria (2>30) bundle optical fiber A input end face 1
Align it to the center of 7. This allows the movable slit (1) 2
The Ishikawa slit 27 of No. 5 coincides with the input end surface 17 of the bundle optical fiber A. In this state, light amount data is taken and set as light amount data 1. Next, the movable slit (1) 25 standards (3)
31)! - Align the bundle optical fiber A with the center of the incident end face 17. As a result, the surface slit 28 of the movable slit (1) 25 coincides with the input end surface 17 of the bundle optical fiber A. In this state, the light amount data is taken as light amount data 2. Similarly, the reference (2) 45 of the movable slit (2>32) is aligned with the center of the input end face 22 of the bundle optical fiber F.

As a result, the Ishikawa slit 42 of the movable slit (2) 32
coincides with the input end face of the bundle optical fiber F. In this state, light amount data is taken and set as light amount data 3. Next, the reference (3>46) of the movable slit (2) 32 is aligned with the center of the bundle optical fiber F input end face 22. As a result, the surface slit 43 of the movable slit (2) 32 coincides with the bundle optical fiber F input end face 22. In this state, light amount data is taken and set as light amount data 4.

The above-mentioned light amount data are compared, and the optical axis of the second laser beam is moved and adjusted so that the light amount data 1 and the light amount data 2 and the light amount data 3 and the light amount data 4 are respectively equal.

With the above, the positions of the observation points A-F3 to A-F8 can be made to coincide with the position through which the laser beam 2 passes.

〔Effect of the invention〕

As explained above, the present invention provides a dedicated slit for alignment by installing a movable slit in front of the incident end face of the bundle optical fiber to allow only a part of the scattered light image to pass through. This has the effect of eliminating the need for bundled optical fibers and four dedicated photodetectors, resulting in significant cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a plasma measuring device according to the present invention, and FIG. 2 is a block diagram showing an example of a conventional plasma measuring device. DESCRIPTION OF SYMBOLS 1... Plasma, 2... Laser light, 3-8... Observation point A - Observation point F, 9... Condensing lens, 10... Image forming surface. 11-16...Bundle optical fibers A-F, 17-2
2... Bundle optical fibers A to F input end faces. 23... Spectrometer, 24... Photodetector, 25... Movable slit (1), 26.41... Fully open slit, 2
7゜42... Ishikawa slit, 28.43... Surface slit, 29.44... Standard (1), 30.45...
・Standard (2), 31.46...Standard (3), 32...
・Movable slit) (2), 33... Photodetector A useful, 3
4...Photodetector A right use, 35...Photodetector F useful,
36...Photodetector F surface phase, 37...Alignment A
Useful end face, 3B... End face for alignment A left, 39
Alignment F right end face, 40... Alignment F left end face.

Claims (1)

[Claims] 1. A condensing lens for condensing scattered light of a laser from a plurality of observation points of plasma generated in a tokamak-type nuclear fusion device onto an imaging plane, and condensing the light onto an imaging plane. A plurality of bundled optical fibers are used to guide the scattered light from the plasma to a spectrometer, a spectrometer is used to separate the scattered light guided by the bundled optical fibers, and the spectrum separated by the spectrometer is electrically transmitted. In a plasma measurement device that measures plasma by having a photodetector for converting it into a signal, the incidence of two bundle optical fibers disposed on the outermost side of the image forming plane among the plurality of bundle optical fibers. A fully open slit is installed in front of the end face and allows all of the incident end faces of the two bundled optical fibers to receive the image formed by the scattered light when performing normal plasma measurement, and a fully open slit is installed in front of the end face and receives the image formed by the scattered light on all of the input end faces of the two bundle optical fibers when performing normal plasma measurement. 1. A plasma measuring device comprising a movable slit including a right slit and a left slit for receiving an image formed by the scattered light on the right half and the left half of an input end face of one bundle optical fiber. 2. The plasma measuring device according to claim 1, wherein the plurality of observation points are set on an optical path of laser light that is irradiated onto the plasma and scattered.