X-ray spectral imaging apparatus and method based on acousto-optic monochromator

Abstract

This invention patent proposes an X-ray spectral imaging device and method based on an acousto-optic monochromator. It mainly includes a light source, a slit, a sample, a detector, a two-dimensional scanning mechanism, an acousto-optic crystal, an ultrasonic generator, a piezoelectric transducer, and a computer. The light source generates polychromatic X-rays, the slit generates a measurement beam, the detector measures the intensity of the terahertz beam, the two-dimensional scanning mechanism scans the sample to achieve spatial imaging, the ultrasonic generator generates ultrasonic waves and transmits them to the acousto-optic crystal, the piezoelectric transducer converts electrical signals into mechanical signals, and the computer controls the entire device. Compared with existing common X-ray spectral imaging devices, the new device proposed in this invention has advantages such as low cost and high measurement speed.

Description

Technical Field

[0001] This invention relates to the field of X-ray spectral imaging, and in particular to an X-ray spectral imaging device and method based on an acousto-optic monochromator. Background Technology

[0002] X-ray spectral imaging has a wide range of applications, not only enabling spatial imaging of samples but also obtaining their spectral information.

[0003] Existing common X-ray spectral imaging devices such as Figure 1 As shown, it mainly includes a light source (1), a slit (2), a crystal monochromator (3), a sample (4), a detector (5), and a two-dimensional scanning mechanism (6). The light source is used to generate polychromatic X-rays, the slit is used to generate a measurement beam, the crystal monochromator is used to generate continuously adjustable monochromatic X-rays, the detector is used to measure the intensity of the terahertz beam, and the two-dimensional scanning structure is used to scan the sample to achieve spatial imaging.

[0004] This device can accurately measure the diffraction efficiency spectrum of a grating, but its main drawback is that the mechanical structure inside the crystal monochromator needs to perform intermittent, discontinuous movements during the measurement process, resulting in a slow spectral testing speed and a long spectral imaging time. This limits the application of existing technology in many fields. Summary of the Invention

[0005] To address the problems existing in current X-ray spectral imaging methods, this invention provides an X-ray spectral imaging device and method based on an acousto-optic monochromator.

[0006] The technical solution of the present invention is as follows: an X-ray spectral imaging device, such as... Figure 1 As shown, the device includes a light source (1), a slit (2), a sample (4), a detector (5), a two-dimensional scanning mechanism (6), an acousto-optic crystal (7), an ultrasonic generator (8), a piezoelectric transducer (9), and a computer (10). The light source is used to generate polychromatic X-rays, the slit is used to generate a measurement beam, the detector is used to measure the intensity of the terahertz beam, the two-dimensional scanning mechanism is used to scan the sample to achieve spatial imaging, the ultrasonic generator is used to generate ultrasonic waves and transmit them to the acousto-optic crystal, the piezoelectric transducer is used to convert electrical signals into mechanical signals, and the computer is used to control the entire device.

[0007] This invention also proposes an X-ray spectral imaging method, comprising the following steps: ① Measure the dark field intensity value of detector (4) with slit (2) closed; ② Open the slit (2), do not place the sample in the optical path, and let the test beam directly irradiate the detector (5); ③ By using an ultrasonic generator (8), a piezoelectric transducer (9), and a computer (10), the emission wavelength of the acousto-optic crystal (7) is changed, and the bright field intensity value of the detector (5) is measured at each wavelength. ④ Install the sample (4) in the optical path and move the sample (4) to the initial measurement position through the two-dimensional scanning mechanism (6); ⑤ By using an ultrasonic generator (8), a piezoelectric transducer (9), and a computer (10), the emission wavelength of the acousto-optic crystal (7) is changed, and the signal intensity value of the detector (5) is measured at each wavelength to calculate the transmission spectrum of the sample (4) at the initial measurement position. ⑥ Move the sample (4) to the next measurement position using the two-dimensional scanning mechanism (6), and repeat step ⑤; ⑦ Repeat step ⑥ until all sampling locations on sample (4) have been measured. Advantages of the present invention

[0008] Compared to crystal monochromators (wavelength switching speed on the order of seconds), acousto-optic monochromators composed of piezoelectric transducers and acousto-optic crystals can rapidly switch the output wavelength of X-rays (wavelength switching speed on the order of milliseconds). Therefore, compared to existing common X-ray spectral imaging devices, the new device proposed in this invention has advantages such as faster measurement speed (by hundreds of times) and lower cost. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of a common existing X-ray spectral imaging device.

[0010] Figure 2 This is a schematic diagram of an X-ray spectral imaging device based on an acousto-optic monochromator proposed in this invention patent. Detailed Implementation

[0011] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but this should not be construed as limiting the scope of protection of the present invention.

[0012] according to Figure 2 The structure was designed to construct an X-ray spectral imaging device. The light source was the Shanghai Synchrotron Radiation Facility, with a photon energy range of 0.1-40 keV. The slit size was 200 μm × 200 μm. The acousto-optic material was TeO2 crystal. The scanning range of the two-dimensional scanning mechanism was 100 × 100 mm. The X-ray detector was a single-pixel light intensity detector.

[0013] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. 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. An X-ray spectral imaging device, comprising a light source (1), a slit (2), a sample (4), a detector (5), a two-dimensional scanning mechanism (6), an acousto-optic crystal (7), an ultrasonic generator (8), a piezoelectric transducer (9), and a computer (10). The slit (2) is placed in the direction of the light beam emission from the light source (1), and the acousto-optic crystal (7) is placed in the direction of the propagation of the light beam emitted from the slit (2). The sample (4) and the detector (5) are in the direction of the propagation of the light beam emitted from the acousto-optic crystal (7). The detector (5) is used to measure the intensity of X-rays. The two-dimensional scanning mechanism (6) is used to scan the sample (4) to achieve spatial imaging. The ultrasonic generator (8) is used to generate ultrasonic waves and transmit them to the acousto-optic crystal (7). The piezoelectric transducer (9) is used to convert electrical signals into mechanical signals. The computer (10) is used to control the entire device.

2. The X-ray spectral imaging device according to claim 1, characterized in that, The light source (1) is a synchrotron radiation source or a miniaturized X-ray source.

3. The X-ray spectral imaging apparatus according to claim 1, characterized in that, The acousto-optic crystal (7) is made of lead molybdate, lead molybdate, or tellurium dioxide.

4. An X-ray spectral imaging method, comprising the following steps: ① Measure the dark field intensity value of the detector (4) with the slit (2) closed; ② Open the slit (2), do not place a sample in the optical path, and let the test beam directly irradiate the detector (5); ③ By using the ultrasonic generator (8), the piezoelectric transducer (9) and the computer (10), the emission wavelength of the acousto-optic crystal (7) is changed, and the bright field intensity value of the detector (5) is measured at each wavelength. ④ Install the sample (4) in the optical path and move the sample (4) to the initial measurement position through the two-dimensional scanning mechanism (6); ⑤ By using the ultrasonic generator (8), the piezoelectric transducer (9) and the computer (10), the emission wavelength of the acousto-optic crystal (7) is changed, and the signal intensity value of the detector (5) is measured at each wavelength to calculate the transmission spectrum of the sample (4) at the initial measurement position. ⑥ Move the sample (4) to the next measurement position using the two-dimensional scanning mechanism (6), and repeat step ⑤; ⑦ Repeat step ⑥ until all sampling positions on the sample (4) have been measured.

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