Device and method for measuring in-situ time-resolved X-ray absorption spectrum

Abstract

Device and method for measuring in-situ time-resolved X-ray absorption spectrum. The device comprises an X-ray source, a first slit, an acousto-optic tunable X-ray filter, a radio frequency transmitter, a second slit, a front ionization chamber, a front ionization chamber signal amplifier, a sample to be tested, a rear ionization chamber, a rear ionization chamber signal amplifier, a data collector, and a computer. The X-ray source, the acousto-optic tunable X-ray filter, and the radio frequency transmitter are used to generate a monochromatic X-ray beam; the front ionization chamber is used to measure the intensity of the X-ray beam before passing through the sample; the rear ionization chamber is used to measure the intensity of the X-ray beam after passing through the sample; the front ionization chamber signal amplifier, the rear ionization chamber signal amplifier, the data collector, and the computer are used for data acquisition and data processing.

Claims

1. A device for measuring in-situ time-resolved X-ray absorption spectrum, comprising: an X-ray source (1), a first slit (2), an acousto-optic tunable X-ray filter (9), a radio frequency transmitter (10) having an input and sending out an excitation signal, a second slit (4), a front ionization chamber (5) having an output signal, a front ionization chamber signal amplifier (11), a sample to be tested (6), a rear ionization chamber (7) having an output signal, a rear ionization chamber signal amplifier (13), a data collector (12) having an output, and a computer (14) having an input and an output, wherein the first slit (2) and the acousto-optic tunable X-ray filter (9) are arranged sequentially along the light beam emitting direction of the X-ray source (1); the second slit (4), the front ionization chamber (5), the sample to be tested (6), and the rear ionization chamber (7) are arranged sequentially along the light beam emitting direction of the acousto-optic tunable X-ray filter (9); the output signal of the front ionization chamber (5) is amplified by the front ionization chamber signal amplifier (11), and then transmitted to the data collector (12); the output signal of the rear ionization chamber (7) is amplified by the rear ionization chamber signal amplifier (13), and then transmitted to the data collector (12); the output of the data collector (12) is connected with the input of the computer (14); the output of the computer (14) is connected with the input of the radio frequency transmitter (10); and the excitation signal sent by the radio frequency transmitter (10) is transmitted to the acousto-optic tunable X-ray filter (9).

2. The device of claim 1, wherein the acousto-optic tunable X-ray filter (9) further comprises a sound absorber (15), an X-ray crystal (16), and a piezoelectric crystal transducer (17).

3. A method for measuring in-situ time-resolved X-ray absorption spectrum by using the device of claim 1, comprising: (1) setting a wavelength of photon emitted by the acousto-optic tunable X-ray filter (9) to an initial wavelength λ.sub.1 by the radio frequency transmitter (10) according to a wavelength range of an X-ray absorption spectrum to be measured (λ.sub.1, λ.sub.n); (2) using the front ionization chamber (5) and the rear ionization chamber (7) through the data collector (12), the front ionization chamber signal amplifier (11), and the rear ionization chamber signal amplifier (13), to simultaneously measure an intensity I.sub.0 of an incident X-ray beam before passing through the sample to be tested (6) and an intensity I.sub.1 of the incident X-ray beam passes through the sample to be tested (6), and calculating an optical absorption coefficient μ.sub.1 of the sample to be tested (6) at the wavelength λ.sub.1 position according to an equation: $\begin{array}{cc}{\mu }_{{\lambda }_1}=\ln \frac{I_0}{I_1};& \left(1.1\right)\end{array}$ (3) sequentially setting wavelengths of photon emitted by the acousto-optic tunable X-ray filter (9) to λ.sub.2, λ.sub.3 . . . λ.sub.n-1 and λ.sub.n by the radio frequency transmitter (10), and repeating the step (2) at each wavelength position to obtain the optical absorption coefficient μ.sub.λ.sub.2, μ.sub.λ.sub.3 . . . μ.sub.λ.sub.n-1 and μ.sub.λ.sub.n at each wavelength position; and (4) drawing an X-ray absorption spectrum of the sample to be tested (6) in the wavelength range (λ.sub.1, λ.sub.n) according to the optical absorption coefficient μ.sub.λ.sub.2, μ.sub.λ.sub.3 . . . μ.sub.λ.sub.n-1 and μ.sub.λ.sub.n.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows the structure of the device for measuring time-resolved X-ray absorption spectrum in the prior art.

(2) FIG. 2 shows the structure of the device for measuring time-resolved X-ray absorption spectrum of the present invention.

(3) FIG. 3 shows the structure of the acousto-optic tunable X-ray filter.

DETAILED DESCRIPTIONS OF THE INVENTION AND EMBODIMENTS

(4) In combination with the figures and the embodiment hereunder, the present invention is described in details, but the scope of protection for the present invention is not limited to the figures and the embodiment described below.

(5) In one embodiment of the present invention, the device for measuring time-resolved X-ray absorption spectrum, as shown in FIG. 2, mainly comprises an X-ray source 1, a first slit 2, an acousto-optic tunable X-ray filter 9, a radio frequency transmitter 10, a second slit 4, a front ionization chamber 5, a front ionization chamber signal amplifier 11, a sample to be tested 6, a rear ionization chamber 7, a rear ionization chamber signal amplifier 13, a data collector 12, and a computer 14. X-ray source 1 is used to provide the light source for X-ray absorption spectrum measurement, generally a synchrotron radiation accelerator; the complex X-ray beam emitted from the X-ray source 1 passes through the first slit 2 to form a high-quality X-ray beam; the first slit 2 has functions of limiting the aperture of the X beam and suppressing stray light; the collimated X beam passing through the first slit 2 is incident into the acousto-optic tunable X-ray filter 9, and a monochromatic X-ray beam is formed after the action of the acousto-optic tunable X-ray filter 9; the radio frequency transmitter 10 is used to provide a modulation signal for the acousto-optic tunable X-ray filter 9, thereby controlling the wavelength of the X-ray beam output by the acousto-optic tunable X-ray filter 9; the second slit 4 is used to limit the aperture of the X-ray beam output by the acousto-optic tunable X-ray filter 9 and suppress stray light; the front ionization chamber 5 is used to measure the intensity of the X-ray beam before passing through the sample; the rear ionization chamber 7 is used to measure the intensity of the X-ray beam after passing through the sample 6; the front ionization chamber signal amplifier 11 is used to amplify the output signal of the front ionization chamber 5; the rear ionization chamber signal amplifier 13 is used to amplify the output signal of the front ionization chamber 7; the data collector 12 is used to collect output signals of the front ionization chamber signal amplifier 11 and the rear ionization chamber signal amplifier 13; the computer 14 is used to control the radio frequency transmitter 10 and the data collector 12 to realize functions of fast data acquisition and data processing.

(6) In the present invention, the acousto-optic tunable X-ray filter comprises a sound absorber 15, an X-ray crystal 16, and a piezoelectric crystal transducer 17.

(7) The method for measuring in-situ time-resolved X-ray absorption spectrum of the present invention comprises the following steps:

(8) (1) The wavelength of photon emitted by the acousto-optic tunable X-ray filter 9 is set to initial wavelength λ.sub.1 by the radio frequency transmitter 10 according to the wavelength range of the X-ray absorption spectrum to be measured (λ.sub.1, λ.sub.n).

(9) (2) Through the data collector 12, the front ionization chamber signal amplifier 11 and the rear ionization chamber signal amplifier 13, the front ionization chamber 5 and the rear ionization chamber 7 are used to simultaneously measure the intensity of the incident X-ray beam before passing through the sample to be tested 6 I.sub.0 and the intensity of the incident X-ray beam passes through the sample to be tested 6 I.sub.1, and the optical absorption coefficient μ.sub.1 of the sample to be tested 6 at the wavelength λ.sub.1 position is calculated according to the following equation:

(10) $\begin{array}{cc}{\mu }_{{\lambda }_1}=\ln \frac{I_0}{I_1}.& \left(1.1\right)\end{array}$

(11) (3) The wavelengths of photon emitted by the acousto-optic tunable X-ray filter 9 are sequentially set to λ.sub.2, λ.sub.3 . . . λ.sub.n-1 and λ.sub.n by the radio frequency transmitter 10; step {circle around (2)} is repeated at each wavelength position to obtain the optical absorption coefficient μ.sub.λ.sub.2, μ.sub.λ.sub.3 . . . μ.sub.λ.sub.n-1 and μ.sub.λ.sub.n at each wavelength position.

(12) (4) The X-ray absorption spectrum of the sample to be tested 6 in the wavelength range (λ.sub.2, λ.sub.n) is drawn according to the optical absorption coefficient μ.sub.λ.sub.3, μ.sub.λ.sub.3 . . . μ.sub.λ.sub.n-1 and μ.sub.λ.sub.n.

(13) The present invention does not have any movement of mechanical parts during the measurement process, and therefore can realize time-resolved measurement of X-ray absorption spectrum, and further has high measurement precision for X-ray absorption spectrum.

(14) The specific embodiment described above further explain the objectives, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only for the specific embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., which are made within the spirit and principles of the present invention, should be included in the scope of protection of the present invention.