JPH0875550A - Echell spectroscope - Google Patents

Abstract

PURPOSE: To measure the light over a wide wavelength region through an inexpensive and compact constitution by mounting a grating for reflecting and separating lights of short and long wavelength regions, respectively, on a same turn table as a reflection prism. CONSTITUTION: A reflection prism 4 comprising a BK 7 deposited with aluminum on the rear side and a grating 5 are stood on a same turn table T and a light diffracted through an echelle grating 6 and exiting an exit slit 8 is measured through reflection and separation. Since the prism 4 reflects and separates the light in long wavelength region (e.g. 320-800nm) and the grating 5 reflects and separated the light in short wavelength region (e.g. 160-320nm), the light can be measured over a wide region from ultraviolet region to visible region through rotational operation of a table T. Furthermore, since a degree separation rotational system is employed, positional accuracy of the rotary shaft S is loosened and since the prism 4 and grating 5 can be arranged on one table T, compaction and cost reduction can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high dispersion and high resolution echelle spectroscope using an echelle diffraction grating.

[0002]

2. Description of the Related Art In recent years, in emission spectroscopy, a high temperature (about 6000 ° C.) light source such as inductively coupled high frequency plasma (ICP) has been widely used, and a large number of spectral lines emit light, causing spectral interference. Was becoming.

Therefore, avoidance of spectral interference is a major premise, and a high-dispersion and high-resolution spectrograph has been demanded, and the Echelle spectroscope has attracted attention as a device that meets such a demand.

The echelle spectroscope uses an echelle diffraction grating having a relatively small number of grooves (number of engraved lines) in order to avoid difficulties in manufacturing technology, and can obtain high resolution by utilizing a high-order spectrum. This is configured as shown in FIG. 4, for example. In FIG. 4, reference numeral 1 denotes a light source, 2 an entrance slit, 3 a first concave spherical mirror, 4 a transmissive prism, 6
Is an echelle diffraction grating, 7 is a second concave spherical mirror, 8 is an exit slit, and 9 is a detector.

With such a structure, a two-dimensional spectrum is obtained by separating the spectra with overlapping orders by the transmissive prism 4, and the inverse linear dispersion is improved.

[0006]

However, in the above-mentioned conventional Echelle spectroscope, the prism for separating the spectrum in the ultraviolet region having a relatively short wavelength is expensive, so that there is a problem that the cost becomes high. . For example, 160 nm
In the above, CaF ₂ is used, and in the case of 180 nm or more, fused quartz or the like is used, but both are expensive. On the other hand, when a grating is used for order separation, there is a problem that the orders overlap.

The present invention has been made in view of such circumstances.
It is an object of the present invention to provide an echelle spectroscope that can measure a wide wavelength range and is inexpensive.

[0008]

The present invention has means for solving the above-mentioned problems as follows. In other words, the invention according to claim 1 is an echelle spectroscope that detects light emitted from a light source through an entrance slit, diffracted by an echelle diffraction grating, and then emitted from an exit slit, and detects the emitted light. A grating for reflecting / separating light in the short wavelength range diffracted by the echelle diffraction grating, and a reflecting prism for reflecting / separating light in the long wavelength range. .

According to a second aspect of the invention, the grating and the reflection prism in the first aspect of the invention are provided on the same turntable.

According to a third aspect of the present invention, the grating and the reflection prism in the first aspect of the invention are arranged vertically, and the light reflected and separated by the grating and the light reflected and separated by the reflection prism are arranged. And two emission slits for emitting the emitted light separately,
It is characterized in that two detectors are provided for individually detecting the emitted light.

[0011]

According to the first aspect of the invention, the wavelength band is shared by the grating and the reflecting prism, and light in a wide wavelength range from the ultraviolet region to the visible region can be spectrally detected.

According to the second aspect of the present invention, by rotating the turntable, the short wavelength side is the grating and the long wavelength side is the reflecting prism, and the wavelengths can be shared by the gratings to achieve compactness. .

[0013]

Embodiments of the Echelle spectroscope of the present invention will be described in detail below with reference to the drawings. 1 and 2 show the basic configuration of an Echelle spectroscope, in which reference numeral 1 is a light source such as inductively coupled high frequency plasma (ICP), 2 is an entrance slit, and 3
Is the first concave spherical mirror, and 4 is the BK7 whose back surface is vapor-deposited with aluminum.
And the like, 5 is a grating, T is a turntable in which the reflecting prism 4 and the grating 5 are erected, 6 is an echelle diffraction grating, 7 is a second concave spherical mirror, 8 is an exit slit, and 9 is a detector. Is.

The reflection prism 4 described above is responsible for reflection / separation of the spectrum in the long wavelength region (for example, 320 to 800 nm), and the grating 5 is responsible for reflection and separation of the spectrum in the short wavelength region (for example, 160 to 320 nm). The wavelength range can be measured separately. FIG. 1 shows the position of the turntable T when measuring light in the long wavelength region and FIG. 2 when measuring light in the short wavelength region. The turntable T may be rotated by a motor or manually.

In this way, the reflecting prism 4 can be arranged together with the grating 5 on the single turntable T, and the compactness can be realized. Further, in the perfect Littrow arrangement, the rotation axis S of the turntable T must be on the reflection surfaces of the reflection prism 4 and the grating 5, but in the present invention, since the rotation method is used only for order separation, Since the positional accuracy of the rotation axis S is relaxed, it is possible to arrange the reflecting prism 4 and the grating 5 back to back on the single turntable T as described above.

As described above, according to the present invention, since the reflecting prism 4 and the grating 5 are arranged on the single turntable T, the size can be reduced and the light in a wide wavelength range can be measured. .

Further, an expensive prism for the short wavelength region is not required, and an inexpensive prism such as BK7 can be adopted, so that the cost can be largely reduced.

FIG. 3 shows a different embodiment, in which the reflection prism 4 and the grating 5 are fixedly arranged vertically and two second concave spherical mirrors 7A, 7B, emission slits 8A, 8B and detectors 9A, 9B are provided. Since it is provided, the rotation mechanism is unnecessary. A device for finely adjusting the angle between the reflection prism 4 and the grating 5 is necessary.

[0019]

As described above, according to the Echelle spectroscope of the present invention, a grating for reflecting / separating light in the short wavelength region and a reflecting prism for reflecting / separating light in the long wavelength region. Since the and are provided, it is possible to use an inexpensive BK7 or the like for the reflecting prism, and it is possible to reduce the cost.

Further, by arranging the grating and the reflecting prism on the same turntable, it is possible to make the device compact.

Alternatively, if the grating and the reflecting prism are arranged vertically and are detected by separate detectors, it is not necessary to provide a rotating mechanism, and the structure can be simplified.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram showing a state in which the turntable is rotated 180 degrees.

FIG. 3 is a configuration diagram showing a different embodiment of the same echelle spectroscope.

FIG. 4 is a configuration diagram showing an example of a conventional Echelle spectroscope.

[Explanation of symbols]

1 ... Light source, 2 ... Incident slit, 4 ... Reflective prism, 5 ...
Grating, 6 ... Echelle diffraction grating, 8, 8A, 8
B ... Emitting slit, 9, 9A, 9B ... Detector.

Claims (3)

[Claims] 1. An echelle spectroscope, wherein light from a light source passes through an entrance slit, is diffracted by an echelle diffraction grating, is then emitted from an exit slit, and the emitted light is detected. An Echelle spectroscope comprising a grating for reflecting / separating light in the short wavelength region diffracted by, and a reflecting prism for reflecting / separating light in the long wavelength region. 2. The Echelle spectroscope according to claim 1, wherein the grating and the reflection prism are provided on the same turntable. 3. The grating and the reflection prism are arranged one above the other, and two lights are emitted for separately emitting the light reflected / separated by the grating and the light reflected / separated by the reflection prism, respectively. The Echelle spectroscope according to claim 1, wherein the slit and two detectors for individually detecting the emitted light are provided.