Light splitting system and time resolution system for ultrafast continuous measurement
By modulating synchrotron X-ray pulses into picosecond-interval photon pulses using a spectrometer system and combining this with a detector, continuous measurement of non-repeatable ultrafast processes was achieved. This solved the problem of existing technologies being unable to meet the requirements for high frame rate observation, improved the time resolution to the microsecond and nanosecond levels, and was applied to ultrafast experiments at synchrotron radiation source devices.
Patent Information
- Application Number
- CN202511531037.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-24
- Publication Date
- 2026-02-24
AI Technical Summary
Existing technologies cannot achieve continuous measurement of non-repeatable ultrafast processes, mainly due to the lack of sufficiently strong ultrafast continuous pulses and high frame rate detectors, which makes it impossible to meet the observation requirements of microsecond, nanosecond and even faster time resolution.
A beam splitting system consisting of multiple sets of four-crystal monochromators and beam dividers is used to modulate the X-ray pulse bundle emitted by the synchrotron radiation undulator into a series of X-ray photon pulses with picosecond intervals. Time-resolved observations are performed using sub-beams of different energies, and data is received and processed by a detector.
It has improved the ability to perform rapid and continuous measurements from the millisecond to microsecond level to the microsecond, nanosecond, and picosecond level, enabling the measurement of instantaneous processes and solving scientific problems such as molecular dynamics, explosion mechanisms, and the evolution of impact materials.
Smart Images
Figure CN121558192A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of synchrotron radiation technology and relates to a spectroscopic system and a time-resolved system for ultrafast continuous measurement. Background Technology
[0002] The ultrafast experimental methods currently used on synchrotron radiation source devices generally refer to pump-probe experiments, which involve triggering with a laser pulse, measuring with an X-ray pulse, adjusting the time interval between the two pulses, measuring one point at a time, and completing time-resolved observations of a process through a large number of repeated measurements.
[0003] The core idea is to utilize two ultrashort pulses to perform the functions of excitation and detection, respectively. First, a strong pulse (pump) acts on the sample, exciting the system from the ground state to a non-equilibrium state, inducing dynamic evolution of degrees of freedom such as electrons, lattice, or spin. Subsequently, with a set time delay, a relatively weaker pulse (detector) irradiates the sample to acquire the physical information of the system at that instant. By continuously changing the time delay between the pump and detector pulses, snapshots of the system throughout the entire evolution process can be obtained, thereby reconstructing its ultrafast dynamic behavior.
[0004] Because pump-probe detection requires repeated measurements, it is only applicable to repeatable processes and cannot detect many transient, non-repeatable processes. To achieve continuous measurement of non-repeatable ultrafast processes, two technical bottlenecks currently exist: first, a sufficiently strong ultrafast continuous pulse is required; second, an ultrafast detector is needed. Regarding light sources, current synchrotron radiation facilities can achieve picosecond-level X-ray pulse widths and repetition rates of hundreds of megaHz; X-ray free-electron laser pulse widths can reach femtosecond levels, with repetition rates of megaHz. For two-dimensional array detectors, indirect measurement X-ray detectors can achieve frame rates up to ten megaHz, mainly limited by the CMOS chip frame rate and the fluorescence effect of the scintillator conversion screen. For direct measurement two-dimensional pixel array detectors, the highest frame rate currently available is 50kHz, which cannot meet the demands of faster dynamic observations.
[0005] Continuous observation of ultrafast processes is an indispensable tool for studying dynamic processes in many fields. Numerous scientific problems urgently need to be solved across different timescales. For example, the study of explosion mechanisms and additive manufacturing requires time resolution at the microsecond level or higher; the evolution of material impact processes requires sub-microsecond resolution; molecular dynamics requires characterization methods at the nanosecond, picosecond, or even faster levels; and the study and mechanism analysis of fusion processes also require ultrafast continuous measurement methods and technologies at the picosecond level. Summary of the Invention
[0006] To address the problems existing in the prior art, the present invention aims to provide a spectroscopic system and a time-resolved system for ultrafast continuous measurement. This invention combines optical technology, utilizing the optical path difference of X-rays of different energies to modulate X-ray pulse bundles emitted by a synchrotron radiation undulator into a series of picosecond-interval X-ray photon pulses.
[0007] The technical solution of this invention is as follows: A beam splitting system, characterized in that it includes multiple sets of quad-crystal monochromators, a beam stop, and an attitude adjustment mechanism; Each of the aforementioned attitude adjustment mechanisms is equipped with a quad-crystal monochromator for adjusting the attitude and position of the quad-crystal monochromator; wherein, different groups of quad-crystal monochromators are used to separate a sub-beam of different energy from the light emitted by the light source and adjust its optical path, and the adjusted sub-beams are merged into the same optical axis. The beam block is used to prevent unmodulated beams of light emitted from the light source from propagating along the optical axis.
[0008] Preferably, each group of four-crystal monochromators includes four beam-splitting elements; wherein, the first beam-splitting element in the i-th group of four-crystal monochromators diffracts the incident light to separate a sub-beam of target energy as the i-th sub-beam, which is then reflected sequentially by the remaining three beam-splitting elements in the i-th group of four-crystal monochromators onto the optical axis, and the optical path of the i-th sub-beam is adjusted by adjusting the positions of several beam-splitting elements in the i-th group of four-crystal monochromators; the remaining energy beams in the incident light are transmitted through the first beam-splitting element in the i-th group of four-crystal monochromators and output to the first beam-splitting element in the (i+1)-th group of four-crystal monochromators.
[0009] Preferably, the energy of the i-th sub-beam diffracted by the i-th group of four crystal monochromators is less than the energy of the (i+1)-th sub-beam diffracted by the (i+1)-th group of four crystal monochromators.
[0010] Preferably, the spectral dispersive element of the quad-crystal monochromator is a diamond crystal or a diamond multilayer film.
[0011] A time-resolved system for ultrafast continuous measurement, characterized in that it includes a synchrotron radiation undulator, a beam splitter, and a detector; The synchrotron radiation undulator, as a light source, is used to emit multiple harmonic X-rays with different energies. The beam splitting system is used to divide the light emitted by the synchrotron radiation undulator into multiple sub-beams of different energies according to different harmonic orders, and to adjust the optical path of each sub-beam. Then, the adjusted sub-beams are combined to obtain a series of pulse bundles with a set time interval, which are used to illuminate the sample to be observed to generate multiple sets of different images or data; wherein, different pulse bundles have different energies. The detector is used to receive the image or data.
[0012] Preferably, the optical path difference between the two sub-beams with the closest optical path after adjustment is on the order of millimeters, and the pulse interval between adjacent pulse bundles after beam combining is on the order of picoseconds.
[0013] Preferably, the beam splitting system diffracts the light emitted from the light source into different paths for propagation, resulting in multiple sub-beams of different energies.
[0014] A method for continuous measurement in an ultrafast process, comprising the following steps: 1) The light emitted by the light source is divided into multiple sub-beams of different energies by a beam splitting system. The optical path of each sub-beam is adjusted and then combined to obtain a series of pulse bundles with a set time interval. These pulse bundles are then used to illuminate the sample to be observed, generating multiple sets of different images or data. The different pulse bundles have different energies. 2) The detector receives the images or data and performs further processing to obtain the observation results.
[0015] The advantages of this invention are as follows: Existing pump-probe techniques cannot measure non-repeatable, transient processes. This invention modulates the X-ray pulse bundle emitted by a synchrotron radiation undulator into a series of picosecond-interval X-ray photon pulses. This not only enables the measurement of transient processes but also elevates the rapid, continuous measurement capabilities for diffraction, scattering, and imaging from the current international millisecond-microsecond level to the microsecond, nanosecond, and picosecond levels. Furthermore, it addresses a series of major scientific questions related to molecular dynamics, explosion mechanisms, the evolution of impact materials, and the performance of fusion materials. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of a three-beam cluster spectral system.
[0017] Figure 2(a) shows the incident beam before it is modulated.
[0018] Figure 2(b) shows the output beam pattern after the beam is modulated.
[0019] Reference numerals: 1- Spectroscopic element in the first group of four-crystal monochromators, 2- Spectroscopic element in the second group of four-crystal monochromators, 3- Spectroscopic element in the third group of four-crystal monochromators, 4- Beam block. Detailed Implementation
[0020] The present invention will now be described in further detail with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.
[0021] The focus of this invention is the spectroscopic system. As the name suggests, spectroscopic technology involves diffraction of X-rays of different energies from a synchrotron radiation pulse, splitting them into different paths for propagation. The optical path length of each path can be adjusted as required, and the length of the optical path determines the order in which they arrive at the sample. The longer the optical path, the later the arrival time at the sample. Finally, when the beams of different energies are combined and hit the sample, a series of X-ray pulse bundles with specific time intervals are achieved, and each bundle has a corresponding energy.
[0022] The light emitted by a synchrotron radiation undulator is composed of multiple harmonics, where the wavelength of the nth harmonic is: in It is an odd harmonic because even harmonics are suppressed under the symmetry of a sinusoidal magnetic field. The oscillator period length, The observation angle (generally observed on the axis) ), Let K be the relativistic factor, and K be a dimensionless parameter representing the undulator's magnetic field strength and the amplitude of electron motion, defined as: in, e is the electron energy, and e is the electron charge. The peak value of the undulator's magnetic field. Let be the electron mass, and c be the speed of light in a vacuum.
[0023] Figure 1 The principle of a diffraction energy-dispersive beam system is presented. The system consists of multiple sets of four-crystal monochromators, a beam stop, and an attitude adjustment mechanism. The attitude adjustment mechanism has the capability to adjust the distance and angle in both horizontal and vertical directions. Energy selection is controlled by the angle, and the optical path difference is adjusted by the distance, ensuring that all emitted light beams return to the same axis. The beam stop blocks unwanted X-rays, ensuring that only the separated light is received.
[0024] Because diamond has low absorption, the spectroscopic elements of a spectral system can be made of diamond or diamond coated with a multilayer film. The former has a narrower diffraction bandwidth and therefore better monochromaticity, while the latter has higher luminous flux. The specific choice can be made based on the actual experimental requirements.
[0025] Figure 1Taking a three-beam split as an example (the specific number of beams can be increased or decreased depending on experimental needs), the splitting path for each energy level consists of a set of four-crystal monochromators (four beam-splitting elements), for a total of three sets. Each beam-splitting element has an independent attitude adjustment mechanism, allowing for precise adjustment of its position and angle. The first beam-splitting element in each set of four-crystal monochromators diffracts the target energy X-ray beam from the incident beam, while X-rays of other energies are transmitted and continue to propagate. The last beam-splitting element returns the X-ray beam of that energy to the same output path. The optical path can be changed by adjusting the specific positions of the four beam-splitting elements.
[0026] The principle of selecting energy by angle is that diffracted light must satisfy Bragg's law, that is: Where d is the interplanar spacing of the crystal. denoted by Bragg angle (diffraction occurs only when the Bragg condition is met), and k is the diffraction order (generally only the first-order diffraction is selected). The wavelength of the target X-ray is given. Therefore, the X-ray energy can be selected by adjusting the incident angle. Since high-energy X-rays have strong penetrating power and low-energy X-rays have weak penetrating power, low-energy X-rays are diffracted first, while high-energy X-rays penetrate first and then diffract.
[0027] Different groups use different harmonics, that is, they use light of different energies; Figure 1 For example, if we want to separate the first, third, and fifth harmonics, then the first group of four-crystal monochromators is used to filter the first harmonic, the second group of four-crystal monochromators is used to filter the third harmonic, and the third group of four-crystal monochromators is used to filter the fifth harmonic.
[0028] Figures 2(a) and 2(b) illustrate the temporal characteristics of the beams before and after beam splitting. As shown in Figure 2(a), the X-ray pulse bundles incident on the system have the same temporal characteristics (overlapping on the time scale), but after being split and modulated by three sets of crystals, the emitted beams are three X-ray pulse bundles with different energies and a certain time interval, which can reach the picosecond level.
[0029] Finally, users can use these picosecond-interval photon pulses to observe many ultrafast processes.
[0030] Although specific embodiments of the invention have been disclosed for illustrative purposes to aid in understanding and implementing the invention, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the invention should not be limited to the content disclosed in the preferred embodiments, and the scope of protection claimed by the invention is defined by the claims.
Claims
1. A spectroscopic system, characterized in that, Includes multiple sets of quad-crystal monochromators, beam stops, and attitude adjustment mechanisms; Each of the aforementioned attitude adjustment mechanisms is equipped with a quad-crystal monochromator for adjusting the attitude and position of the quad-crystal monochromator; wherein, different groups of quad-crystal monochromators are used to separate a sub-beam of different energy from the light emitted by the light source and adjust its optical path, and the adjusted sub-beams are merged into the same optical axis. The beam block is used to prevent unadjusted beams of light emitted from the light source from propagating along the optical axis.
2. The spectral splitting system according to claim 1, characterized in that, Each group of four-crystal monochromators includes four beam-splitting elements. The first beam-splitting element in the i-th group of four-crystal monochromators diffracts the incident light to separate a sub-beam of target energy as the i-th sub-beam. The i-th sub-beam is reflected onto the optical axis by the remaining three beam-splitting elements in the i-th group of four-crystal monochromators. The optical path of the i-th sub-beam is adjusted by adjusting the position of several beam-splitting elements in the i-th group of four-crystal monochromators. The remaining energy beams in the incident light are transmitted through the first beam-splitting element in the i-th group of four-crystal monochromators and output to the first beam-splitting element in the (i+1)-th group of four-crystal monochromators.
3. The spectral splitting system according to claim 2, characterized in that, The energy of the i-th sub-beam diffracted by the i-th group of four crystal monochromators is less than the energy of the (i+1)-th sub-beam diffracted by the (i+1)-th group of four crystal monochromators.
4. The spectral splitting system according to claim 1, 2, or 3, characterized in that, The beam-splitting element of the quad-crystal monochromator is a diamond crystal or a diamond crystal coated with a multilayer film.
5. A time-resolved system for ultrafast continuous measurement, characterized in that, This includes synchrotron radiation undulators, beam splitters, and detectors; The synchrotron radiation undulator, as a light source, is used to emit multiple harmonic X-rays with different energies. The beam splitting system is used to divide the light emitted by the synchrotron radiation undulator into multiple sub-beams of different energies according to different harmonic orders, and to adjust the optical path of each sub-beam. Then, the adjusted sub-beams are combined to obtain a series of pulse bundles with a set time interval, which are used to illuminate the sample to be observed to generate multiple sets of different images or data; wherein, different pulse bundles have different energies. The detector is used to receive the image or data.
6. The time-resolved system according to claim 5, characterized in that, The optical path difference between the two sub-beams with the closest optical path after adjustment is on the order of millimeters, and the pulse interval between adjacent pulse bundles after beam combining is on the order of picoseconds.
7. The time-resolved system according to claim 5, characterized in that, The beam splitting system diffracts the light emitted from the light source into different paths for propagation, resulting in multiple sub-beams of different energies.
8. A method for continuous measurement in an ultrafast process, comprising the following steps: 1) The light emitted by the light source is divided into multiple sub-beams of different energies by a beam splitting system. The optical path of each sub-beam is adjusted and then combined to obtain a series of pulse bundles with a set time interval. These pulse bundles are then used to illuminate the sample to be observed, generating multiple sets of different images or data. The different pulse bundles have different energies. 2) The detector receives the images or data and performs further processing to obtain the observation results.
9. The method according to claim 8, characterized in that, The beam splitting system diffracts the light emitted from the light source into different paths for propagation, resulting in multiple sub-beams with different energies. The optical path difference between the two sub-beams with the closest optical path after adjustment is on the order of millimeters, and the pulse interval between adjacent pulse bundles after beam combining is on the order of picoseconds.