Optical splitter

Abstract

The invention described herein is a spectrometer having components that allow for the crystal analyzer and detector to be remotely located.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to U.S. Provisional Application No. 62 / 924,009, filed on October 21, 2019, the entire contents of which are incorporated herein by reference.

[0002] Description of Federally Sponsored Research or Development Not applicable

[0003] Incorporation by Reference of Material Submitted on a Compact Disk Not applicable

Background Art

[0004] The spectrometer (hereinafter referred to as "spectrometer") is used to separate the X-rays that are the object for quantitative analysis. The general process of wavelength-dispersive fluorescence spectrometry is first to induce the generation of X-rays characteristic of a specific element using an incident X-ray from a radiation source, such as an X-ray tube or a synchrotron beam, or incident particle radiation such as a beam of electrons, protons, or ions. Once the X-rays are generated in the sample, they are selected using a crystal analyzer having a fixed lattice spacing. When the X-rays from the sample hit the crystal analyzer at a specific angle, only the X-rays with a wavelength that satisfies Bragg's law diffract. By controlling the position of the sample and the size of the irradiation area, the X-rays having an energy band and emitted from different regions of the sample can be made to interact with the crystal analyzer and diffract. In the geometric arrangement of the Rowland circle, diffraction occurs such that the X-rays are spatially sorted by their energy when the X-rays are re-imaged onto the Rowland circle. This is combined with a position-sensitive X-ray detector (hereinafter referred to as the detector), and by placing the detector on this circle, these re-imaged X-rays are measured, and the X-rays measured on the detector are assigned to a specific energy using the relationship between the re-imaging position and the energy. Alternatively, when using a single-channel detector (not position-sensitive), the spectrometer can be operated in a point-to-point focus mode, in which a single X-ray energy is measured by the detector for each point.

[0005] In the geometric arrangement of the Rowland circle, the Rowland circle is defined by the position of the crystal analyzer, and the detector should ideally be tangent to this circle. Once the Rowland circle is determined, the sample and the detector must be arranged symmetrically with respect to the crystal analyzer for the X-rays to be analyzed to diffract towards the detector. Generally, since the sample is fixed because the position of the exciting X-ray or incident beam is fixed, when trying to change the angle between the crystal and the detector to change the Bragg angle of the X-rays from the sample or the source and the measured energy region, both the crystal analyzer and the detector must be moved to maintain the Rowland geometric arrangement.

[0006] Therefore, analyzing the fluorescence lines of various elements of the sample with a spectrometer requires constantly realigning the crystal analyzer and the detector. There is a need for a spectrometer that can accurately align these components and, if necessary, realign them. Also, the realigning device should enable the alignment of the spectrometer in an environment such as a vacuum or an inert air glove box or chamber without disturbing the environment. In one embodiment, the inert air glove box or chamber is filled with helium. In another embodiment, the spectrometer is installed in a vacuum chamber or a chamber filled with helium, and such a spectrometer has mainly two uses. First, this spectrometer may be used to measure the energy spectrum of the X-ray photons emitted from the sample. This fluorescence X-ray spectroscopy is known as X-ray emission spectroscopy (XES) when performed with very high energy resolution. This method can be carried out because X-rays are incident on the sample, or it can also be carried out when electrons or other charged particles are incident on the sample, for example, in an electron microscope or a system for proton-induced XES. Second, the X-ray tube or source may be directed towards the entrance of the spectrometer so that the spectrum of the photon energy emitted by the X-ray source itself is formed on the detector.

[0007] In this case, the sample is inserted between the radiation source and the analyzer, or between the analyzer and the detector. Therefore, by analyzing the change in the spectral intensity caused by the insertion of the sample, the X-ray absorption fine structure (XAFS) of the sample can be determined. Described herein is a spectrometer having a platform for operating and positioning a crystal analyzer and a detector.

SUMMARY OF THE INVENTION

[0008] The invention described herein is a spectrometer having components that enable remotely positioning a crystal analyzer and a detector.

[0009] Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments (which will be finalized when the drawings are finalized), with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]

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Figure 8d

[0011] In the following detailed description, reference is made to the accompanying drawings, which form a part of the description. In the drawings, when similar or identical symbols are used in different drawings, they typically represent similar or identical items, unless otherwise specified in the context.

[0012] The exemplary embodiments described in the detailed description, the drawings, and the claims are not intended to be limiting. Other embodiments may be utilized and other changes may be made without departing from the spirit or scope of the subject matter presented herein.

[0013] Those skilled in the art will recognize that the components (e.g., operations), devices, objects, and associated considerations described herein are used as examples for clarity of concept and that various modifications of the configurations are contemplated. As a result, the specific examples and associated considerations described herein are intended to represent their more general classes. In general, regardless of which specific example is used, it is intended to be representative of its class and should not be construed as limiting simply because it does not include a particular component (e.g., operation), device, and object.

[0014] In this application, formal summary headings are used for ease of presentation. However, it should be understood that the summary headings are for presentation purposes and that various types of subject matter may be considered throughout the application (for example, an apparatus / structure may be described under a process / operation heading and / or a process / operation may be considered under a structure / process heading and / or a description of a single topic may span two or more topic headings). Thus, the use of formal summary headings is not intended in any way to be limiting.

[0015] Referring to FIG. 1, according to an embodiment, a spectrometer (100) comprises a detector (40) and a crystal analyzer (30) that may be rotatably disposed about a first axis; in some embodiments, the axis is at the center on a Rowland circle (60) having a radius r. Generally, the detector (40) and the crystal analyzer (30) may be disposed independently of each other along the Rowland circle (60) such that a line source (51) is within the range of the light receiving region of Bragg diffraction by the crystal analyzer (30).

[0016] The crystal analyzer (30) is operably attached to the first arm (1a), whereby the position of the first arm (1a) is controlled by the first electric motor (20a). The first arm (1a) has a distal end (21b) and a proximal end (21a). In certain embodiments, the first electric motor (20a) is operably attached to the distal end (21b) of the first arm (1a). The crystal analyzer (30) is operably attached to the distal end (21b) of the first arm (1a). In certain embodiments, the crystal analyzer (30) is mounted on the distal end (21b) using any known mounting method. The first electric motor (20a) moves the first arm (1a) that moves the center of the Rowland circle while maintaining the crystal analyzer (30) in a tangential state. In certain embodiments, the crystal analyzer (30) is mounted so as to be rotatable about its mounting point. In certain embodiments, the crystal analyzer is mounted such that its radial position r can be adjusted so that the crystal analyzer approaches or moves away from the first axis. In certain embodiments, the crystal analyzer (30) is of the Johann type, and the surface of the crystal is curved along a circle twice the size of the Rowland circle. In certain embodiments, the crystal analyzer (30) is of the Johansson type, where the crystal lattice plane is curved to have a radius twice the size of the Rowland circle, while the surface of the crystal is ground / fabricated to have the same radius as the Rowland circle. In certain embodiments, a diffraction grating is used instead of the crystal analyzer.

[0017] The first arm (1a) is operably attached to the second arm (1b). The second arm (1b) has a proximal end (22a) and a distal end (22b). The proximal end (21a) of the first arm (1a) is operably connected to the proximal end (22a) of the second arm (1b). The distal end (22b) of the second arm (1b) is operably connected to the detector (40). In certain embodiments, the detector (40) is mounted on the second arm using any known mounting method. In certain embodiments, the detector (40) is mounted on the second arm such that the detection surface is perpendicular to the second arm (1b). In certain embodiments, the detector is mounted such that its radial position r can be adjusted.

[0018] The second arm (1b) is connected to the third arm (1c). The third arm (1c) has a proximal end (23a) and a distal end (23b). The distal end (22b) of the second arm (1b) is operably connected to the proximal end (23a) of the third arm (1c). In certain embodiments, the second arm (1b) is operably connected to the third arm (1c) such that the detector (40) moves tangentially along a circle.

[0019] The third arm (1c) is connected to the fourth arm (1d). The fourth arm has a proximal end (24a) and a distal end (24b). The proximal end (23a) of the third arm (1c) is operably connected to the proximal end (24a) of the fourth arm (1d). The distal end (24b) of the third arm (1d) is operably connected to the second motor (20b). In certain embodiments, the second motor (20b) is mounted on the fourth arm (1d) by any known mounting method. The second motor (20b) rotates the fourth arm (1d).

[0020] In certain embodiments, a computing device (not shown) controls the first motor (20a) and the second motor (20b). FIGS. 8a through 8d illustrate exemplary embodiments of the spectrometer at several Bragg angles.

[0021] Referring to FIGS. 1, 2a, 2b, and 2c, in one embodiment, the crystal analyzer (30) is configured to receive X-rays emitted by or transmitted through the sample (51). In one embodiment, the crystal analyzer (30) operates by selectively scattering radiation within a specific wavelength / energy band range via Bragg diffraction based on the lattice spacing of the crystal analyzer (30) and the orientation of the crystal analyzer (30) with respect to the sample (51). In another embodiment, the crystal analyzer (30) operates by selectively scattering radiation within a specific wavelength / energy band range via Bragg diffraction based on the lattice spacing of the crystal analyzer (30) and the orientation of the crystal analyzer (30) with respect to the radiation source (50). In one embodiment, the crystal analyzer (30) is shaped cylindrically. In one embodiment, the crystal analyzer (30) is shaped annularly. In one embodiment, the crystal analyzer (30) is shaped spherically. In one embodiment, the crystal analyzer (30) has a focusing circle with a diameter of about 10 - 20 cm. In another embodiment, the crystal analyzer (30) has a focusing circle with a diameter of about 20 - 100 cm. In one embodiment, the detector (40) is configured to detect the count, intensity, and / or energy / wavelength of the X-rays diffracted by the crystal analyzer (30). One skilled in the art will recognize that the detector (40) may be a position-sensitive detector or a single-channel detector depending on the configuration. One skilled in the art will recognize that the crystal analyzer (30) and the detector (40) may each include various materials to achieve the desired configuration.

[0022] Referring to FIGS. 1, 2a, 2b, and 2c, in one embodiment, the first arm (1a) and the second arm (1b) are configured such that the crystal analyzer (30) and the detector (40) maintain a state of being tangent to the Rowland circle (60). In one embodiment, the first motor (20a) rotates the first arm (1a), and the second motor (20b) changes the angle A between the detector (40) and the crystal analyzer (30), so as to rotate the arm (1d) and then the other connected arms (1b, 1c). In one embodiment, the first motor (20a) rotates the first arm (1a), and the second motor (20b) maintains the angle A between the detector (40) and the crystal analyzer (30) and the angle B between the crystal analyzer (30) and the sample (51) to be equal while the sample (51) remains stationary, so as to rotate the arm (1d) and then the other connected arms (1b, 1c). In one embodiment, the first motor (20a) or the second motor (20b) can be independently operated to adjust the positions of the crystal analyzer (30) and the detector (40). By adjusting this angle, it becomes possible to measure X-rays from a source or a sample (51) having different wavelengths by the detector (40) so as to satisfy Bragg's law.

[0023] Referring to FIG. 3, in one embodiment, the spectrometer (100) is operably mounted on a linear translation stage (70). The linear translation stage (70) moves the motorized spectrometer (100) from at least a first position X1 to a second position X2, thereby changing the distance between the sample (51) and the crystal analyzer (30) while keeping the sample-crystal-detector angle constant. Referring to FIG. 6, in one embodiment, the spectrometer (100) is housed within an inert air glove box (200). In one embodiment, the spectrometer (100) is housed within a vacuum chamber or a chamber filled with helium. In one embodiment, the spectrometer (100) is positioned such that the Rowland circle is in a vertical plane. In one embodiment, the spectrometer (100) is positioned such that the Rowland circle is in a horizontal plane.

[0024] Referring to FIG. 4, in one embodiment, the radiation source (50) may be an X-ray tube, a synchrotron, a laser plasma X-ray source, a scanning electron microscope, a proton beam, or an ion beam. The radiation source (50) may be configured to emit X-rays towards the sample (51) such that the emission of radiation from the sample (51) towards the crystal analyzer (30) is caused by the radiation source (50). In this embodiment, the detector (40) measures the X-ray emission spectrum of the sample (51). As used herein, the sample (51) may be any material. Those skilled in the art will recognize that when referring to the sample (51), it is to be understood that the sample (51) is operably connected to the radiation source, whether or not the radiation source is explicitly referenced.

[0025] Referring to FIG. 5, in one embodiment, the radiation source (50) is in the form of an X-ray tube. In one embodiment, the radiation source (50) may be configured to emit X-rays towards the crystal analyzer (30), and the sample (51) may be disposed between the radiation source (50) and the crystal analyzer (30), or between the crystal analyzer (30) and the detector (40). By comparing the signals on the detector (40) with and without the sample (51), the fine structure of the X-ray absorption of the sample (51) can be determined. In other embodiments, the radiation source (50) may be in the form of a synchrotron or a laser plasma X-ray source.

[0026] In one embodiment, the spectrometer is utilized to study actinide elements. In one embodiment, the spectrometer is utilized to study air-sensitive electrode materials for electrical energy storage. In one embodiment, the spectrometer is utilized to study air-sensitive materials for chemical catalytic reactions.

[0027] In one embodiment, the computing device is programmed to control the motors (20a, 20b), and then the arms (1a, 1b, 1c, 1d), to achieve multiple angles between the crystal analyzer (30) and the sample (51) or the radiation source (50). In one embodiment, the computing device is pre-programmed to control the motors (20a, 20b) to position the crystal analyzer (30) and the detector (40) at defined positions, such as a specific energy of elemental radiation. In one embodiment, the second motor (1b) rotates the fourth arm (1d), and thus the other connected arms (1c, 1b, 1a), so as to move the detector (40) while keeping the crystal analyzer (30) stationary.

[0028] The high-resolution spectra of FIGS. 7a and 7b were obtained using a spectrometer (100) and by using electricity to tune to different energy ranges (i.e., emission lines). In an exemplary embodiment, the sample is a compound containing either phosphorus or sulfur. In the cases of phosphorus and sulfur, the Kα spectrum consists of two peaks with close spacing. For the phosphorus compound, the energy separation is about 0.85 eV, and for the sulfur compound, the energy separation is about 1.24 eV. The ability to clearly separate these two different peaks demonstrates an energy resolution of <1 eV.

[0029] FIGS. 7a and 7b further show the energy shift that occurs between a sample in a very low oxidation state (e.g., ZnS with an oxidation state of S = -2) and a sample in a high oxidation state (e.g., CaSO4·2H2O with an oxidation state of S = +6). In the case of phosphorus, this energy shift is about 0.8 eV, and in the case of sulfur, this shift is about 1.35 eV. This measurement can be used to determine the chemical species of a sample with a mixed oxidation state. FIG. 7c shows that a sample that was initially CoS has some sulfur converted to SO4 2-Exemplifies detecting both oxidation states when indicating being oxidized. In certain embodiments, the spectrometer measurements are used to determine the oxidation state distribution of phosphorus and sulfur, such as the oxidized and reduced percentages.

[0030] Although various exemplary aspects and exemplary embodiments have been disclosed herein, other aspects and embodiments will be apparent to those of ordinary skill in the art. The various exemplary aspects and exemplary embodiments disclosed herein are for illustrative purposes only and are not intended to be limiting.

Claims

1. A spectrometer comprising a detector and a crystal analyzer; the crystal analyzer is operably attached to a first arm; the detector is operably attached to a second arm; the first arm and the second arm are connected; the detector and the crystal analyzer move around a first axis and move independently of each other, further comprising a linear translation stage, the spectrometer being operably mounted on the linear translation stage such that the linear translation stage moves the spectrometer from at least one first location to at least one second location.

2. The spectrometer according to claim 1, wherein the axis is at the center on a Rowland circle having a radius.

3. The spectrometer according to claim 2, wherein the first arm and the second arm are configured such that the crystal analyzer and the detector are tangent to the Rowland circle.

4. The spectrometer according to claim 3, wherein the Rowland circle is in a vertical plane.

5. The spectrometer according to claim 3, wherein the Rowland circle is in a horizontal plane.

6. The spectrometer according to claim 1, further comprising a sample holder, the sample holder being located along the radiation path between the radiation source and the crystal analyzer.

7. The spectrometer according to claim 1, further comprising a sample holder, the sample holder being located along the radiation path between the crystal analyzer and the detector.

8. The spectrometer according to claim 1, wherein the sample is within the range of the light receiving region of Bragg diffraction by the crystal analyzer.

9. The spectrometer according to claim 1, which is used for studying actinide elements.

10. The spectrometer according to claim 1, wherein the crystal analyzer has a cylindrical shape.

11. The spectrometer according to claim 1, wherein the crystal analyzer has an annular shape.

12. The spectrometer according to claim 1, wherein the crystal analyzer has a spherical shape.

13. The spectrometer according to claim 1, which is located within a chamber of an inert gas.

14. The spectrometer according to claim 13, which is used for studying an air-sensitive electrode material for electrical energy storage.

15. The spectrometer according to claim 13, which is used for studying an air-sensitive material for chemical catalytic reactions.

16. The spectrometer according to claim 1, which is located within a vacuum chamber.

17. The spectrometer according to claim 1, which is located within a chamber filled with helium.

18. The spectrometer according to claim 1, wherein the crystal analyzer is of the Johann type.

19. The spectrometer according to claim 1, wherein the crystal analyzer is of the Johansson type.

20. The spectrometer according to claim 1, wherein at least the first arm is operably attached to an electric motor.

21. The spectrometer according to claim 1, which is used for measuring the oxidation state distribution.

22. The spectrometer according to claim 1, wherein a diffraction grating is used instead of the crystal analyzer.

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