JPS61129539A - Spectrometer - Google Patents

Abstract

PURPOSE:To prevent the spectrometer from protruding from the substrate of a photoelectric detector and to standardize a unit and to reduce its size by changing the direction of the photodetection surface of the photoelectric detector without reference to the direction of light incident from an entrance slot and the wavelength dispersion direction of a dispersing element. CONSTITUTION:The entrance slit 1, diffraction grating 2, and the photoelectric detector are mounted on the substrate 4. Then, a photodetection part 5 is arranged in the detector 3 slantingly to a plane crossing its depth direction 3a at right angles and its photodetection surface is parallel (right opposite) to the wavelength dispersion direction of diffracted light from the diffraction grating 2. Namely, a microchannel plate (MCP)5 which operates as the photodetection part and a fluorescent plate 6 are arranged slanting to a housing 30 and an array sensor 8 and a circuit part 9 do not slant to the housing. A fiber plate 7 is made wedgelike so as to correct the inclination of the MCP5 and fluorescent plate 6 to the array sensor 8. Consequently, the depth direction of the detector 3 is nearly parallel to the optical axis of the incident light L1 and the whole unit is mounted without protruding from the substrate 4.

Description

[Detailed description of the invention] (Technical field of invention) The present invention relates to a spectrometer.

(Background of the Invention) Conventionally, an entrance slit, a dispersive element, a photoelectric detector, etc. are arranged on one substrate to form a plurality of spectroscopic units according to the wavelength range of spectroscopic measurement, and to house the spectroscopic units. A spectroscopic device is known in which the spectroscopic unit is removably provided in a container (for example, Japanese Patent Laid-Open No. 58-68629). This type of spectrometer was developed to simultaneously measure light emitted from, for example, nuclear fusion plasma over multiple wavelength ranges. When the wavelength to be measured is in the vacuum ultraviolet region, each spectroscopic unit is housed in a vacuum container connected to the fusion reactor. In this case, if the spectroscopic unit becomes large, the vacuum container housing it also becomes large, resulting in an increased load on the vacuum pump.

This will be explained with reference to FIG. In FIG. 1, the spectroscopic unit consists of an entrance slit 1, a dispersive element 2, a photoelectric detector 3 and a unit substrate 4. The photoelectric detector 3 is a microchannel plate (Microchannel plate).
The photoelectric conversion unit includes a plate (hereinafter referred to as MCP) 5, a fluorescent plate 6, a fiber plate 7, and an array sensor 8, and an electric circuit unit 9. MCP is made by bundling a large number of thin glass tubes (channels) with an inner diameter of 10 to 20 μm, and coating the inner wall of each channel with a secondary Kame emission material, making each channel a continuous secondary electron multiplier. . The bundled channels are then cut to a predetermined thickness. Now, the light incident on each channel of the MCP 5 is photoelectron multiplied there and impinges on the fluorescent plate 6. The fluorescent plate 6 converts the electrons emitted from the MCP 5 into visible light, the fiber plate 7 transmits the visible light corresponding to each channel to the 7-ray sensor 8, and the array sensor 8 converts the visible light corresponding to each channel into visible light. Each converts photoelectrically. In this type of spectroscopy unit, in order to be able to attach and detach it to the vacuum container, the inlet slit 1,
A dispersion element 2 and a photoelectric detector 3 are placed on a substrate. However, in the photoelectric detector, since the cut surface of the MCP 5 is arranged obliquely with respect to the substrate 4 along the imaging plane of the dispersive element 2 or in the vicinity thereof, the entire spectroscopic unit cannot be moved. The locus (trajectory of movement when attaching and detaching the spectroscopic unit to and from the vacuum container) increases depending on the inclination of the photoelectric detector 3. Therefore, the above-mentioned drawbacks occurred.

(Objective of the Invention) An object of the present invention is to provide a spectrometer that can be miniaturized, thereby making it convenient to standardize spectrometers that measure different wavelength ranges into a common unit.

(Summary of the Invention) The present invention achieves the above object by changing the direction of the light-receiving surface of a photoelectric detector, regardless of the direction of light incident from the entrance slit and the direction of wavelength dispersion by the dispersion element. According to the present invention, the photoelectric detector includes at least an entrance slit, a dispersion element that disperses light incident from the entrance slit in a direction different from the direction of incidence, and a light receiving section that receives the dispersed light. In the spectrometer, the depth direction of the casing of the photoelectric detector is parallel to the incident direction or the principal ray direction of the center wavelength of the dispersed light, and the light receiving section is arranged in the depth direction to receive the dispersed light. A spectrometer is provided that is tilted relative to a plane orthogonal to the plane. The light receiving section includes a microchannel plate, and the dispersion element includes a diffraction grating and a crystal dispersion element.

(Example) Hereinafter, the present invention will be explained based on examples.

FIG. 2 is an explanatory diagram showing an embodiment of the present invention. The entrance slit 1, the diffraction grating 2 and the photodetector 3 are mounted on the substrate 4. This becomes the spectrometer unit. The light receiving section 5 is arranged inside the photoelectric detector 3 at an angle with respect to a plane perpendicular to the depth direction of the photoelectric detector. This depth direction is the depth direction 3a of the rectangular casing 30 of the photoelectric detector. At this time, the light receiving section 5 is arranged at or near the imaging plane of the diffraction grating 2. Here, the light-receiving surface of the light-receiving section 5 is parallel to (directly opposite to) the wavelength dispersion direction of the diffracted light by the diffraction grating 2 . The wavelength dispersion direction is defined as the diffraction angle β = (βl + β
This is the direction perpendicular to the principal ray (the ray diffracted at the center of the diffraction grating) having a wavelength of n)/2 (center wavelength).

As a result, the depth direction of the photoelectric detector 3 is the incident light L! almost parallel to the optical axis of Therefore, the entire spectrometer unit can be placed without protruding from the substrate 4. This means that when the spectrometer unit is detachably attached to a vacuum vessel (not shown), the movement trajectory Fi of the spectrometer unit within the vacuum vessel is reduced compared to that shown in the first figure.

Therefore, even when spectrometer units are prepared for different wavelength ranges and are detachably attached to one vacuum container, it is possible to prevent the vacuum container from becoming larger.

FIG. 3 specifically shows the structure of the photoelectric detector 3 shown in FIG. The MCP 5, which acts as a light receiving section, is arranged diagonally with respect to the casing 30.

The fluorescent plate 6 is also arranged diagonally following the MCP 5. The array sensor 8 and the circuit section 9 are not particularly inclined with respect to the casing. At least the array sensor 8 receives the incident light 1,
It is arranged in a plane perpendicular to 1. The fiber plate T is wedge-shaped to correct the inclination of the MCP 5 and the fluorescent plate 6 with respect to the 7-ray sensor 8.

FIG. 4 is an explanatory diagram showing another embodiment of the present invention. The casing 30 of the photoelectric detector 3 is arranged in the container 10 so that its depth direction 3a is parallel to the direction of the main diffracted ray at the center wavelength of the diffracted light by the diffraction grating 2.

The MCP 5 is inclined with respect to the housing 30 so as to substantially coincide with the imaging plane of the diffraction grating 2. At this time, the imaging plane is tilted with respect to the wavelength dispersion direction, so the cut plane of the MCP 5 and the plane including the wavelength dispersion direction 20 and perpendicular to the plane of FIG. .

In the above embodiments, a diffraction grating was used as the dispersion element, but a crystal dispersion element may also be used. When using a crystal dispersion element, there are those that generate an imaging plane (such as a Johansson spectrometer), and those that do not have an imaging effect but only spectral lines of specific wavelengths in a specific direction due to the diffraction effect of the crystal. There are some that diffract the spectral lines of the MCP.

However, the present invention is applicable to any of them.

(Effects of the Invention) As described above, according to the present invention, even if the image plane is tilted from the incident direction or the plane perpendicular to the principal ray direction of the center wavelength of the dispersed light due to the characteristics of the dispersive element, the photoelectric detector can be placed along that direction. Therefore, when the spectrometer according to the present invention is used as a spectrometer unit, the photoelectric detector does not protrude from the substrate, and the unit can be standardized and miniaturized. As a result, when spectrometer units with different characteristics are made removably attachable to the unit mounting frame of a vacuum container, the effect of making the vacuum container smaller can be expected.

Furthermore, even if the detector casing becomes larger to improve the functionality of the photoelectric detector, the above-mentioned structure allows the casing to be made longer in the depth direction. There is no need to modify the spectrometer or the spectrometer, or it can be done with a small modification.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a conventional spectrometer, Fig. 2 is an explanatory diagram showing an embodiment of the present invention, Fig. 3 is an explanatory diagram showing the structure of a photoelectric detector, and Fig. 4 is an explanatory diagram showing an embodiment of the present invention. It is an explanatory view showing an example of. (Explanation of symbols of main parts) 1... Entrance slit, 2... Diffraction grating, 3... Photoelectric detector, 5... MCP. 20... wavelength dispersion direction, 30... casing of charging detector, 3a... depth direction of the casing. Figure 2 Figure 3 Figure 3■ Figure 4

Claims (1)

[Claims] 1. Photoelectric detection comprising at least an entrance slit, a dispersion element that disperses light incident from the entrance slit in a direction different from the direction of incidence, and a light receiving section that receives the dispersed light. In the spectrometer, the depth direction of the casing of the photoelectric detector is parallel to the incident direction or the principal ray direction of the center wavelength of the dispersed light, and the light receiving part is configured to receive the dispersed light. A spectrometer, characterized in that the spectrometer is tilted with respect to a plane perpendicular to the depth direction. 2. The photoelectric detector includes a microchannel plate that receives the dispersed light and multiplies photoelectrons, a fluorescent plate that converts the photoelectrons into visible light, an array type photoelectric converter, and the array type photoelectric converter that converts the visible light into visible light. the microchannel plate and the fluorescent plate are inclined with respect to a plane perpendicular to the depth direction, and the array type photoelectric converter is arranged perpendicular to the depth direction. 2. The spectrometer according to claim 1, wherein the fiber section is wedge-shaped to correct the inclination of the microchannel plate and the fluorescent plate with respect to the array type photoelectric converter.