DD279308A1 - ECHELLE DOUBLE SPECTROMETERS IN TETRAEDER ARRANGEMENT - Google Patents

Abstract

The invention relates to an Echelle double spectrometer in tetrahedral arrangement. With it, a lossless coupling of two simultaneously measuring Echelle spectrometers for spectrophotometry to radiation sources with low light conductance is realized. According to the invention, two echelle spectrometers in a tetrahedral arrangement with a common entrance slit arrangement (1.1, 1.2) are coupled with one another such that for both spectrometers the partial section of the optical axis between entrance slit arrangement (1.1, 1.2) and collimator mirror (2, 7) is identical both spectrometers around 180 og Partial section of the optical axis are rotated against each other, that the two collimator (2, 7) are arranged one behind the other and that the front collimator mirror (7) is displaceable on a circular path, the center of which is its Kruemmungsmittelpunkt. figure

Description

This object is achieved by a echelle double spectrometer in a tetrahedral arrangement, consisting of an entrance slit arrangement, two spherical collimator mirrors, two echelle grids, two spherical camera mirrors and. Two focal surfaces, each with a collimator mirror, an echelle grating, a camera mirror and a focal plane! form together with the common entrance slit arrangement a echelle spectrometer in tetrahedral arrangement.

Such an Echelle double Spoktrometer is inventively formed in the manner described below. For both spectrometers the section of the optical axis between the entrance slit arrangement and the collimator mirror is identical. Both spectrometers are arranged rotated by 180 ° relative to each other about said section dsr optical axis. The two collimator mirrors are arranged one behind the other on the optical axis. The collimator mirror closer to the entrance slit arrangement is displaceable in its deflection plane. Its line of motion represents a circular path whose center is the center of curvature of the displaceable collimator mirror.

For order separation, however, the camera mirror may also be formed in at least one of the two einzelon tetrahedral arrangements as a concave diffraction grating in Wadsworth arrangement whose dispersion plane corresponds to the deflection plane of the camera mirror.

The displacement of the front, displaceable collimator mirror causes a partial or complete shading of the rear, fixed Kollimatorspiegels and thus the distribution of incident through the entrance slit array radiation to the two spectrometers.

By the movement on the o.g. special circular path, the movable collimator mirror is ideally adjusted in each position with respect to the associated tetrahedral arrangement. For astigmatism correction in the tetrahedral arrangement, the division of the entrance slit into two partial slits arranged perpendicular to one another, namely the main slit in the direction of the Echelle grating dispersion and the transverse slit in the direction of the transverse dispersion with different distances to the collimator mirror is used. The distance difference between the gap components is a function of the radii of the spherical mirrors and the deflecting angles on the spherical mirrors and on the Echelle grating. For the echelle-double spectrometer according to the invention, the radii and angles are set for the two individual tetrahedral arrangements such that the condition of astigmatism correction in both arrangements is fulfilled by the same distance difference between the gap components of the entrance slit. A solution to this problem exists only in the case of rotation of the two assemblies by 180 ° against each other.

embodiment

The invention will be explained in more detail below using an exemplary embodiment. In the accompanying drawing, the optical arrangement according to the invention is shown schematically. In FIG. 11, the displaceable collimator mirror 7 is in pos. 1. The incident radiation passes from the radiation source 11 through the entrance slit arrangement 1.1, 2.1 onto the fixed collimator mirror 2. The light reflected at the angle Θ passes through the dispersion prism 3 and falls on the echelle. 4. The beam deflected by the grating 4 at the angle θ ι again penetrates the dispersion prism 3 and falls onto the camera mirror 5. From there it is reflected at the angle a ₂ in the focal plane 6, in which the spectral elements of the prism 3 and Echelle-Gilter 4 defined spectral regions are imaged with minimal aberration. It applies

In the case 2, the displaceable collimator is 7 in the pos. 2. The incident radiation passes from the radiation source 11 through the Eitnrittsspaltanordnung 1.1,1.2 on the movable collimator 7. The light reflected at the angle a ₃ falls on the echelle lattice eighth ,

The beam deflected by the grating at the angle Q ₂ falls on the concave grating 9, which deflects the radiation in the Wadsworth arrangement by the angle a _A and images the different spectral elements with minimum aberration into the focal plane 10 at a diffraction angle of approximately 0 °.

In each position of the displaceable Kollimatcspiegels 7 between Pos. 1 and Pos. 2 passes in each case a portion of the incident radiation to the collimator 2, the rest of the part on the Kollimatorspiegel 7. Each component then passes through the respective partial spectrometer in the manner described above, so that a continuous division of the radiation can be realized on the two partial spectrometer.

The construction according to the invention shown in the drawing is realized with the following parameters:

Radius of curvature: R (2 * = R (5) = 750mm

Lattice numbers and blaze angles:

= 75L / mm, 0 _e (4) = = 15OL / mm0 _B (8)

N (9) = 600 L / mm Θ _Β (9) prism angle: ε (3) = 18 ° prism material: quartz deflection angle: 01 = 02 = 6 °

a ₃ = a ₄ = 6 °

Θ, = 8 °

G ₂ = 10 °

Sites and installation angles related to a Cartesian coordinate system with the coordinate origin at the vertex of the fixed collimator mirror 2 are shown in the table.

The optical system is designed for the wavelength ranges of 190nm-350nm for the sub-spectrometer with prism-transverse 3 and 110nm-195nm for the sub-spectrometer with concave grating 9. The extent of the focal surfaces is ^f or both part spectrometer each 20mm χ 20mm. The spectral resolution λ / Δλ is greater than 4 × 10 ⁴ for both partial spectrometers.

table

Component coordinates for the VUWUV Echelle double spectrometer according to the embodiment

components X coordinates 0 Z 0 0 rotation 0 374.5 [Mm | 0 0 90 ° l ° l 0 377.4 y Ü - coordinate origin - 0 <Pv Cross gap (1.2) 0 0 0 0 Hauptspaltfl.1) 0 0 0 collimator -36 11 0 7.7 ° mirror (UV) (2) 342.5 - 3 ° prism -33 0 0 -3.5 ° (1.Fläche) (3) 404 -0.5 58 -4 ° 9 ° echelle 5 0 (UV) (4) -78.5 6 22 ° 9 " Camera mirrors (5) 366 0 -8 ° focal surface 0 0 0 0 (UV) (6) 25 - 8 ° collimator 34 0 0 -6 ° ! VUV) (7) 348 0.5 -57 3 ° -12 ° echelle 30 (VUV) (8) 78 3 -21 ° -12 " Camera grid (9) 366 + ιο focal surface (VUV) (IO) ί o °

(Behind the designation of the components are in parentheses the reference numbers It embodiment and drawing setl)

Claims (3)

1. Echelle double spectrometer in tetrahedral arrangement, consisting of an entrance slit arrangement, two spherical collimator mirrors, two echelle gratings, two spherical camera mirrors and two focal surfaces, each with a collimator mirror, an echelle grating, a camera mirror and a focal plane together with the common entrance slit arrangement an echelle spectrometer in tetrahedral arrangement form, characterized in that for both spectrometers, the portion of the optical axis between the entrance slit arrangement (1.1; 1.2) and collimator mirror (2.7) is identical, that both spectrometers to the said portion of the are rotated by 180 ° from each other that the two collimator (2,7) are arranged on the optical axis one behind the other, that the entrance slit assembly (1.1,1.2) closer collimator (7) is displaceable in its deflection plane and the line of movement of sliding collimator mirror (7) e represents a circular path, the center of which is the center of curvature of the displaceable collimator mirror (7). 2. echelle double spectrometer according to claim 1, characterized in that the order separation in at least one of the two individual tetrahedral arrangements, a dispersion prism (3) in double passage in front of the echelle grating (4) is inserted. 3. echelle double spectrometer according to claim 1, characterized in that for order separation in at least one of the two individual tetrahedral arrangements of the camera mirror is formed as a concave diffraction grating (9) in Wadsworth arrangement whose dispersion plane corresponds to the deflection plane of the camera mirror. For this 1 page drawing Field of application of the invention The invention is applicable in devices for the spectrophotometric examination of radiation sources. Characteristics of the known state "<Jt technology Arrangements for distributing the radiation of a radiation source to two or more simultaneously measuring spectrometers are known per se. In this case, the distribution of the radiation is realized by at least one partially transparent fixed mirror or at least one moving highly reflective mirror, d. H. for at least one of the partial beam paths, an additional reflection occurs. Furthermore, arrangements of two or more sequentially-measuring spectrometer arrangements with a common entrance slit are known, whereby by selectively exchanging one or more of the optical components one and only one of the spectrometer arrangements is activated for measurement (Proceedings of SPIE, Vol. 627 [19861 p. 350-362). In the case of the measurement of spectra of such radiation source ^ whose optical conductivity is less than or equal to the Lichtloitwert the spectrometer, z. For example, stars when observed with telescopes, and whose spectra require the use of two separate spectrometers, e.g. Wide range spectra including UV and VUV range, the o.g. Arrangements the Nachtoüe the additional reflection losses and / or the impossibility of simultaneous measurement. Object of the invention The aim of the invention is to have available an echelle spectrometer with which spectrophotometric examinations of radiation sources can be carried out simultaneously in an extended wavelength range. Explanation of the essence of the invention The 'invention is based on the object of specifying an arrangement which realizes the optical coupling of two simultaneously measuring Echelle spectrometer, wherein a continuous division of the incident through the entrance slit array radiation to the two spectrometers should be possible and the means for splitting the radiation no additional Radiation losses causes.