JPH02280031A - Device for observing position of laser light - Google Patents

Abstract

PURPOSE:To always perform the observation of position by image pickup by controlling the transmittivity of a large output laser light for confirming a position and a small output laser light for setting a position which have different wavelength by means of dichroic mirror corresponding to the sensitivity of an image pickup camera. CONSTITUTION:Incident laser light 12 consists of the large output laser light for confirming the position of plasma and small output laser light for setting the position which have different wavelength. Most of the large output laser light is reflected by 1st and 2nd dichroic mirrors 8 and 9 and most of the small output laser light is transmitted through the mirrors 8 and 9. Then, the laser light reflected by the mirror 8 is absorbed by 1st and 2nd absorption glasses 1 and 2 and the laser light reflected by the mirror 9 is absorbed by a 3rd absorption glass 3. Therefore, at the time of forming a projected image with the large output laser light, input is suppressed to the extent that image pickup is possible and at the time of forming the image with the small output laser light, transmission and absorption are suppressed. The transmission characteristic of the mirror is controlled corresponding to the sensitivity of the image pickup camera, so that the observation of position by image pickup is always performed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a laser advanced t1 observation device I, which projects a high-power laser beam onto plasma generated in a nuclear fusion reactor, and based on the projected image. The present invention relates to a laser beam position observation device 1 for confirming and adjusting the plasma generation position.

[Conventional technology]

A high-power laser beam is projected onto the plasma to adjust and check the fit of the plasma generated in the fusion reactor.
A laser beam position observation device that detects the plasma position by capturing a projected image formed by both using an optical system is a laser beam position observation device that has become well known in recent years.
At l, the high-power laser beam projected onto plus i is
From the standpoint of physical and mental safety, we minimize its use as much as possible, and therefore set the projection position, etc. using a low-power laser beam, and then project the high-power laser beam that will actually be used. has been done.

As a high output laser beam, for example, IT~
30. A ruby laser beam of about T is used, and as a low output laser beam, for example, helium neon (He-
Ne) gas lasers with a power output of around 1 mW are used.

FIG. 4 is a longitudinal sectional view showing an example of a conventional laser beam position observation device. This device consists of a first absorbing glass l that reflects part of the laser beam, transmits about 50% of the remaining laser beam, and absorbs the rest, and a second absorbing glass l that absorbs the laser beam that has passed through the first absorbing glass l. 2, the absorption glass 3 of @3 which absorbs most of the laser beam reflected by the second absorption glass 2 and transmits a part of it, and the absorption glass 3 of @3 which transmits a part of the laser beam which has passed through the third absorption glass 3. a semi-transmissive mirror 5 that reflects a portion of the laser beam; a fourth absorption glass 4 that reflects the semi-transmissive mirror 5 and absorbs the laser beam; a screen 6 that displays the position of the laser beam that has passed through the semi-transmissive mirror 5; It is equipped with an imaging camera 7 that observes the laser beam position displayed on a screen 6 by reflection from a semi-transparent mirror 5, and projects high-output laser beams from a plurality of input windows provided in the plasma generation section of the fusion reactor. , the output light outputted from the output window on the opposite side is received as incident laser light 12, and a projected image is projected onto a screen 6 with a scale and captured by an imaging camera 7. Further, to set the position of the high-power laser beam and confirm the position with respect to changes over time, a low-power laser is obtained as the incident laser beam 12 from the input window through the output window without generating plasma, and a projected image thereof is obtained in the same manner.

By the way, in the above-mentioned conventional laser beam position observation device, when a ruby laser is used as a high output laser beam and a He-Ne laser is used as a low output laser beam, the wavelength is 694.3 nm and the frequency is 1 to 30. C
It is a characteristic diagram illustrating the absorption characteristics of each part and the imaging sensitivity of the imaging camera, both of which receive a small output laser beam from a He-Ne laser of 0.1 mW to 10 m'vV of W. As shown in FIG. 5, in the case of ruby laser light with a wavelength of 694.3n7F+, the energy density on the imaging camera 7 is 14. .3μ
J/c7It, which is the sensitivity of the imaging camera 7, 0,
Since it exceeds 4 J/i, it can be imaged and observed.

On the other hand, in the case of a laser beam with a wavelength of 63 Slnm, the energy density on the imaging camera 7 is 0.36 nWlcrd, which is less than the sensitivity of the imaging camera 7 of 0.2 μW/ffl, so imaging and observation cannot be performed. .

[Problem to be solved by the invention]

The above-mentioned conventional laser beam position observation device has an optical system that uses both a high-power laser beam for plasma position observation and a low-power laser beam for position setting and confirmation of this high-power laser beam.
Since it also has absorption properties, it is not possible to capture the projection image of the low-power laser light due to the combination of the energy of both laser lights and the sensitivity of the imaging camera, and therefore, it is impossible to capture the projection image of the low-power laser light by a method other than imaging. This method has the disadvantage that it is necessary to perform position setting and confirmation.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a laser light position disturbance measuring device that can constantly capture images with low-power laser light.

[Means for Solving Problem 8] The laser beam position observation device of the present invention includes an optical system capable of projecting a high-output first laser beam onto the plasma and imaging it in order to confirm the generation position of plasma in a nuclear fusion reactor. a first projection image forming means that obtains a first projection image corresponding to the potential of the plasma by /J% for setting the projection position of the first laser beam in the same state.
a second projection image forming means for projecting an output second laser beam and obtaining the projection image as a second projection image by the optical system; and a tenth projection image forming means by the first projection image forming means 1. In this case, the input to the optical system is suppressed to the extent that an image can be taken, and the input to the optical system in the case of forming a second projection image by the second projection image forming means t is transmitted to the extent that the image can be taken. The camera is configured to include an imaging level control means controlled by a dichroic mirror as shown in FIG.

〔Example〕

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

The embodiment shown in FIG. 1 includes a first absorption glass 1, a second absorption glass 2, a third absorption glass 3, and a fourth absorption glass 4.
, a semi-transparent mirror 5, a screen 6, an imaging camera 7, and a first dichroic (dichr) directly related to the present invention.
oic) mirror 8 and second dichroic mirror 9
, and a casing 11 including a reflecting mirror IO.

The dichroic mirrors 8.9 are, so to speak, filters for light, and all have the same transmittance versus wavelength characteristics.

In the embodiment shown in FIG. 1, the two laser beams provided as the incident laser beam 12 are a low-power laser beam for position setting and confirmation of a Ne-He laser and a ruby laser, and a high-power laser beam for plasma position observation. When used as light, the transmittance versus wavelength characteristics of these two laser beams are shown in FIG.

That is, the first dichroic mirror 8 and the second dichroic mirror have a wavelength of 694, as shown in FIG.
．． For 3 nm ruby laser light, 0.5% transmission9
9.5% reflection, wavelength 632. ．． 8nT11 He-Ne
For laser light, it has 73% transmission and 27% reflection characteristics.

The incident laser beam 12 passes through a first dichroic mirror 8,
Transmitted through the second dichroic mirror 9 and reflected @110
The light is reflected by the mirror, passes through the semi-transparent mirror 5, and is displayed on the screen 6. This image is observed by the #L image camera 7 through reflection from the semi-transmissive mirror 50.

FIG. 3 shows an example of numerical values for each wavelength of the process in the trench where the incident laser beam forms an image on the imaging camera 7.

In the case of ruby laser light with a wavelength of 694.3 nm, the energy density on the imaging camera 7 is 4.4 μJ/crl, and the sensitivity of the imaging camera 7 used in this example is 0.4 μJ/crl.
Since it exceeds crA, it can be imaged and observed.

Even in the case of He-Ne laser light with a wavelength of 63Z8 nm, the energy density on the imaging camera 7 is 4.7 μW/crI (!
: Since the sensitivity of the imaging camera 7 is sufficiently higher than 0.2 μW/i, imaging and observation can be carried out in the same manner.

Further, about 50% of the energy of the laser beam reflected by the first dichroic mirror 8 is absorbed by the first absorption glass 1, and the remaining energy is absorbed by the second absorption glass.

Furthermore, the energy of the laser beam reflected by the second dichroic mirror 9 is absorbed by the third absorption glass.

In this way, @1 with high output laser light by ruby laser light.
When forming a 0 projection image, the incident laser light to the optical system is suppressed to the extent that the projection image can be captured.
When forming a second projected image for position setting and confirmation using a low-power e-Ne laser beam (in this case, the transmission characteristics of the two dichroic mirrors are adjusted to suppress transmission and absorption to the extent that imaging is possible). By setting , it is possible to capture images under substantially the same conditions in both cases.

〔Effect of the invention〕

As explained above, according to the present invention, the transmittance of the high-power laser beam for plasma level rit observation of different wavelengths and the low-power laser beam for position setting and confirmation, respectively, is
In either case, by controlling the dichroic mirror in the optical path of the optical system so that imaging is possible according to the sensitivity of the imaging camera, it is possible to realize a laser beam position observation device that can perform position observation through constant imaging. .

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of an embodiment of the laser beam position observation device of the present invention, FIG. 2 is a wavelength characteristic diagram of the dichroic mirror in the embodiment of FIG. 1, and FIG. A characteristic diagram showing the absorption of each part in the example, FIG. 4 is a vertical cross-sectional view showing an example of a conventional laser beam position observation device, and FIG. 5 is a characteristic diagram showing the absorption of each part in the conventional example of FIG. 4. It is. 1...First absorption glass, 2...Second
absorption glass, 3...Third absorption glass, 4.
...Fourth absorbing glass, 5... Semi-transparent mirror, 6... Screen, 7... Imaging camera, 8... First dichroic mirror, 9.
...Second dichroic mirror 10...
-Reflector, 11... Housing, 12... Incident laser beam. Agent Patent Attorney Susumu Uchihara 2 ♀ g g 3 g c4 Yumi 8 2
C + City ygJ Kipeto (

Claims (1)

[Scope of Claims] In order to confirm the generation position of plasma in a nuclear fusion reactor, a first laser beam of high power is projected onto the plasma, and a first laser beam corresponding to the position of the plasma is projected by an optical system that can take an image.
a first projection image forming means for obtaining a projection image; and a first projection image forming means for setting the projection position of the first laser beam under the same conditions as when projecting the first laser beam except for the state in which generation of the plasma is stopped. a second projection image forming means that projects a second laser beam with a small output and obtains the projection image as a second projection image by the optical system; and a first projection image by the first projection image forming means. Input to the optical system in the case of formation is suppressed to the extent that an image can be taken, and input to the optical system in the case of the formation of a second projection image by the second projection image forming means is transmitted to an extent to the extent that the image can be taken. A laser beam position observation device comprising: an imaging level control means controlled by a dichroic mirror;