Monochromator system based on transmission grating

Abstract

The invention discloses a monochromator system based on a transmission grating, which comprises a monochromator chamber, two ends of the interior of the monochromator chamber are respectively provided with a slit entering frame and a grating adjusting frame, a mirror bracket is arranged between the slit entering frame and the grating adjusting frame, a focusing toroidal mirror is arranged on the mirror bracket, and the transmission grating is arranged on the grating adjusting frame. An extension rod is arranged at the front end of the monochromator chamber, and a light source is arranged at the end of the extension rod. The device has the advantages that under the condition that the solid angle of the transmission grating is not changed, the incidence angle of the grating is changed through the rotation angle of the grating adjusting frame, light with different wavelengths is output at the same angle after being focused, it is guaranteed that the focused light can be output through the fixed outlet seam, and the device is compact in structure, low in cost and convenient to use. Precise diffraction and stable focusing of soft X-rays can be achieved, and the method is applied to a laser plasma light source and meets the application requirement of the ultra-fast soft X-ray absorption spectrum technology.

Description

Technical Field

[0001] This invention relates to the field of soft X-ray technology, and in particular to a monochromator system based on a transmission grating. Background Technology

[0002] Ultrafast soft X-ray absorption spectroscopy based on laser-plasma sources plays a crucial role in the study of ultrafast chemical reaction processes in energetic materials. Designing a suitable monochromator system based on a transmission grating directly determines the confidence level and precision of the absorption spectral data. Existing soft X-ray grating monochromators mostly employ reflection-type diffraction gratings, which have large grating sizes and require high precision in adjusting the reflection angle, making them unsuitable for use with laser-plasma sources, which have low flux and large divergence angles. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a monochromator system based on a transmission grating.

[0004] The objective of this invention is achieved through the following technical solution: a monochromator system based on a transmission grating, comprising a monochromator chamber, with an entry slit frame and a grating adjustment frame respectively disposed at both ends inside the monochromator chamber, and a mirror frame disposed between the entry slit frame and the grating adjustment frame, a focusing toroidal mirror mounted on the mirror frame, a transmission grating mounted on the grating adjustment frame, an extension rod disposed at the front end of the monochromator chamber, and a light source disposed at the end of the extension rod.

[0005] Preferably, the focal length formula for the focusing toroidal mirror is:

[0006] ;

[0007] ;

[0008] in, Let be the radius of curvature of the meridional plane. Let be the radius of curvature of the sagittal surface. The focal length of the sagittal plane, Angle of incidence It is the focal length of the meridional plane.

[0009] Preferably, the focusing super-toroidal mirror has a meridional radius of curvature of 30,000 mm, a sagittal radius of curvature of 36.5 mm, a meridional width of 50 mm, a sagittal width of 15 mm, and the reflecting surface of the focusing super-toroidal mirror is gold-plated, with a grazing incidence angle of 88°.

[0010] Preferably, the diffraction formula for the transmission grating is:

[0011] ;

[0012] When directly incident ,

[0013] ;

[0014] in, For wavelength The first-order diffraction angle, The grating constant is For diffraction orders;

[0015] When incident at an oblique angle, for the same wavelength Its diffraction angle satisfy:

[0016] ;

[0017] Substitution ,get:

[0018] ;

[0019] Let the wavelength appearing in this direction be... From the equation of the oblique incidence grating:

[0020] ;

[0021] According to the normal incidence relationship ,get:

[0022] ;

[0023] At this point, the original position The wavelength observed at that location becomes When the transmission grating rotates along the axis of the grating, the incident angle is adjusted. It allows observation of light of different wavelengths in the same direction.

[0024] Preferably, the transmission grating has a value of 4000 lp / mm and an effective area of ​​2mm*2mm.

[0025] The present invention has the following advantages: Under the condition that the solid angle of the transmission grating remains unchanged, the incident angle of the grating is changed by rotating the grating adjustment frame, so that the output angle of light of different wavelengths is the same after focusing, ensuring that the focused light can be output through the fixed exit slit. The present invention has a compact structure and low cost, and can realize the precise diffraction and stable focusing of soft X-rays. It can be applied to laser plasma sources and meet the application requirements of ultrafast soft X-ray absorption spectroscopy technology. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a monochromator system based on a transmission grating;

[0027] Figure 2This is a schematic diagram of the dispersion of a transmission grating;

[0028] Figure 3 This is a schematic diagram of ray tracing simulation in Zemax.

[0029] Figure 4 This is a schematic diagram of the Zemax simulation point sequence at 0.1 kev, 1 kev, and 2 kev;

[0030] Figure 5 This is a schematic diagram of the PSF simulation in Zemax at 0.1 keV;

[0031] Figure 6 A schematic diagram of the PSF simulation in Zemax at 1 kev;

[0032] Figure 7 A schematic diagram of the PSF simulation in Zemax at 2keV;

[0033] In the diagram, 1-monochromatic chamber, 3-lens frame, 4-grating adjustment frame, 5-light source, 6-seam mount, 7-focusing toroidal mirror, 8-transmission grating, 9-extension rod. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0038] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0039] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] In this embodiment, as Figures 1-7 As shown, a monochromator system based on a transmission grating includes a monochromator chamber 1. A slit mount 6 and a grating adjustment mount 4 are respectively installed at both ends inside the monochromator chamber 1. A mirror frame 3 is also installed between the slit mount 6 and the grating adjustment mount 4. A focusing toroidal mirror 7 is mounted on the mirror frame 3, and a transmission grating 8 is mounted on the grating adjustment mount 4. An extension rod 9 is installed at the front end of the monochromator chamber 1, and a light source 5 is installed at the end of the extension rod 9. Specifically, the light beam emitted by the light source 5 enters the monochromator chamber 1 through the slit opening on the slit mount 6, and then grazingly incident on the focusing toroidal mirror 7. The function of the focusing toroidal mirror 7 is to focus the incident light at the slit opening to the exit slit opening. The light, after being focused by the focusing toroidal mirror 7, is incident on the transmission grating 8. The light dispersed by the grating will cause different wavelengths of light to be scattered. By rotating the transmission grating 8, monochromatic light of different wavelengths can be selected to pass through the exit slit. This invention, while keeping the solid angle of the transmission grating 8 constant, changes the incident angle of the grating by rotating the grating adjustment frame 4, ensuring that light of different wavelengths outputs at the same angle after focusing. This guarantees that the focused light can pass through the fixed exit slit. This invention has a compact structure and low cost, enabling precise diffraction and stable focusing of soft X-rays. It can be applied to laser plasma sources, meeting the application requirements of ultrafast soft X-ray absorption spectroscopy technology. In this embodiment, the light source 5 is a laser plasma source with a range of 0.1-2 keV and a size of 15 μm.

[0041] Furthermore, the focal length formula for the focusing super-toroidal mirror 7 is:

[0042] ;

[0043] ;

[0044] in, Let be the radius of curvature of the meridional plane. Let be the radius of curvature of the sagittal surface. The focal length of the sagittal plane, Angle of incidence The focal length is the meridional plane. Furthermore, the meridional plane curvature radius of the focusing super-toroidal mirror 7 is 30,000 mm, the sagittal plane curvature radius is 36.5 mm, the width of the meridional plane is 50 mm, the width of the sagittal plane is 15 mm, and the reflecting surface of the focusing super-toroidal mirror 7 is gold-plated, with a grazing incidence angle of 88°.

[0045] In this embodiment, the diffraction formula for the transmission grating 8 is:

[0046] ;

[0047] When directly incident ,

[0048] ;

[0049] in, For wavelength The first-order diffraction angle, The grating constant is For diffraction orders;

[0050] When incident at an oblique angle, for the same wavelength Its diffraction angle satisfy:

[0051] ;

[0052] Substitution ,get:

[0053] ;

[0054] Let the wavelength appearing in this direction be... From the equation of the oblique incidence grating:

[0055] ;

[0056] According to the normal incidence relationship ,get:

[0057] ;

[0058] At this point, the original position The wavelength observed at that location becomes When the transmission grating 8 rotates along the etched axis, the incident angle is adjusted. This allows for the observation of light of different wavelengths in the same direction. In other words, when outputting the desired wavelength, the required rotation angle of the transmission grating 8 is calculated using a formula, and then the grating adjustment frame 4 is controlled to adjust the incident angle of the light to the grating, so that the dispersive beam of the desired wavelength is output from the exit slit. Preferably, the transmission grating 8 has a rotation angle of 4000 lp / mm and an effective area of ​​2 mm * 2 mm. In this embodiment, by observing the Zemax simulation point plots and Zemax simulation PSF plots at 0.1 kev, 1 kev, and 2 kev, it can be seen that the spectral resolution at 0.1 kev, 1 kev, and 2 kev is 1000 < (E / ΔE), indicating high energy spectral resolution. Furthermore, by rotating the grating to change the incident angle while keeping the solid angle of the transmission grating constant, the angle of output of light of different wavelengths after focusing is the same, allowing the focused light to be output through a fixed exit slit.

[0059] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A monochromator system based on a transmission grating, characterized in that: The device includes a monochromator chamber (1), with a slit frame (6) and a grating adjustment frame (4) respectively installed at both ends inside the monochromator chamber (1). A lens frame (3) is also installed between the slit frame (6) and the grating adjustment frame (4). A focusing super-toroidal mirror (7) is installed on the lens frame (3), and a transmission grating (8) is installed on the grating adjustment frame (4). An extension rod (9) is installed at the front end of the monochromator chamber (1), and a light source (5) is installed at the end of the extension rod (9).

2. The monochromator system based on a transmission grating according to claim 1, characterized in that: The focal length formula of the focusing toroidal mirror (7) is: ； ； in, Let be the radius of curvature of the meridional plane. Let be the radius of curvature of the sagittal surface. The focal length of the sagittal plane, Angle of incidence It is the focal length of the meridional plane.

3. The monochromator system based on a transmission grating according to claim 2, characterized in that: The focusing toroidal mirror (7) has a meridional radius of curvature of 30,000 mm, a sagittal radius of curvature of 36.5 mm, a meridional width of 50 mm, a sagittal width of 15 mm, and the reflecting surface of the focusing toroidal mirror (7) is gold-plated with a grazing incidence angle of 88°.

4. The monochromator system based on a transmission grating according to claim 3, characterized in that: The diffraction formula of the transmission grating (8) is: ； When directly incident , ； in, For wavelength The first-order diffraction angle, The grating constant is For diffraction orders; When incident at an oblique angle, for the same wavelength Its diffraction angle satisfy: ； Substitution ,get: ； Let the wavelength appearing in this direction be... From the equation of the oblique incidence grating: ； According to the normal incidence relationship ,get: ； At this point, the original position The wavelength observed at that location becomes When the transmission grating (8) rotates along the etched axis, the incident angle is adjusted. It allows observation of light of different wavelengths in the same direction.

5. The monochromator system based on a transmission grating according to claim 4, characterized in that: The transmission grating (8) has a strength of 4000 lp / mm and an effective area of ​​2 mm * 2 mm.

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