X-ray ultrafast imaging system and method based on radiation conversion and spectral filtering

Abstract

The application provides an X-ray ultrafast imaging system and method based on radiation conversion and spectral filtering, which solves the problems of poor universality, low time resolution or limited number of frames in existing X-ray ultrafast imaging technology. The system comprises an X-ray coupling module for coupling target X-ray signals to image on a semiconductor chip module, a semiconductor chip module for converting the X-ray intensity space-time distribution into the chip refractive index space-time distribution, a chirped pulse light generation module, a chirped pulse light coupling module for irradiating linear chirped pulse light generated by the chirped pulse light generation module to the semiconductor chip module and coupling the pulse light reflected by the semiconductor chip module into a phase extraction module, the phase extraction module, a spectral filtering frame reading module for imaging the linear chirped light intensity space-time distribution signal output by the phase extraction module into the data acquisition module, the data acquisition module and an image processing module for processing the image output by the data acquisition module.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of X-ray ultrafast imaging, and particularly relates to an X-ray multi-frame ultrafast imaging system and method based on radiation conversion and spectral filtering frame reading. BACKGROUND

[0002] X-ray ultrafast imaging technology is widely used in the field of high-energy physics, etc. In the laser-driven inertial confinement fusion experiment, a laser drives a deuterium-tritium target pellet, so that the deuterium-tritium target pellet is imploded and compressed and fusion occurs. The high-temperature and high-density material produced when the implosion compression reaches the maximum degree is the core, and the symmetry of the core hot spot affects the fusion efficiency. Since the evolution process of the core hot spot is in the order of 100 picoseconds, the spontaneous X-ray spectrum can reach hard X-ray. Therefore, the picosecond time-resolved X-ray ultrafast imaging technology is essential for studying the evolution process of the core hot spot and is of great significance for improving the fusion efficiency.

[0003] Traditional ultrafast X-ray imaging techniques include active pumping probe method, traveling wave gating framing technique, solid-state framing technique, etc. The active pumping probe method uses a sub-picosecond free electron laser to irradiate the target, and uses the ultrafast diffraction pattern of the target to invert the target structure. However, the active imaging method limits its application in inertial confinement fusion experiments, and cannot capture the spontaneous X-ray evolution process of high-temperature and high-density plasma. The time resolution of the traveling wave gating framing technique is in the order of hundreds of picoseconds, which cannot meet the capture of dynamic events with a time scale shorter than hundreds of picoseconds. The solid-state framing technique is proposed by K.L. Baker et al. of Lawrence Livermore National Laboratory (K.L. Baker, R.E. Stewart, P.T. Steele, S.P. Vernon, W.W. Hsing, and B.A. Remington, “Solid-state framing camera with multiple timeframes,” Appl. Phys. Lett., vol. 103, p. 151111, Oct. 2013. K.L. Baker, P.T. Steele, R.E. Stewart, S.P. Vernon, W.W. Hsing, and B.A. Remington, “Solid-state framing camera operating in interferometric mode,” Rev. Sci. Instrum., vol. 89, no. 10, p. 10G107, 2018.), which uses a semiconductor chip to realize radiation conversion, converts the X-ray signal to short-wave infrared probe light, and realizes passive ultrafast X-ray imaging with time resolution of 5ps through multi-framing imaging of the probe light. However, the multi-framing imaging of the probe light in the solid-state framing technique is realized by polarization delay and polarization splitting, and the framing number is limited to two, which cannot finely freeze the dynamic information of the target. Therefore, it is urgent to develop an ultrafast X-ray imaging method with time resolution in the order of picoseconds and framing number in the order of dozens. SUMMARY

[0004] In order to solve the technical problems of existing ultrafast X-ray imaging techniques, such as poor universality, time resolution in the order of hundreds of picoseconds, and limited framing number, the present application provides an X-ray ultrafast imaging system and method based on radiation conversion and spectral filtering.

[0005] To achieve the above object, the technical scheme provided by the present application is:

[0006] The application provides an X-ray ultrafast imaging system based on radiation conversion and spectral filtering.

[0007] The X-ray coupling module is used for coupling X-ray signals of a target to form an image on the semiconductor chip module.

[0008] The semiconductor chip module is used for detecting the X-ray signals of the target and converting the X-ray intensity spatial and temporal distribution into the chip refractive index spatial and temporal distribution.

[0009] The chirped pulse light generating module is used for generating linear chirped pulse light.

[0010] The chirped pulse light coupling module is used for expanding and collimating the linear chirped pulse light generated by the chirped pulse light generating module, irradiating the semiconductor chip module, and coupling the linear chirped pulse light carrying the chip refractive index spatial and temporal distribution reflected by the semiconductor chip module into the phase extraction module.

[0011] The phase extraction module is used for extracting the chip refractive index spatial and temporal distribution carried by the linear chirped pulse light into linear chirped light intensity spatial and temporal distribution information.

[0012] The spectral filtering and frame reading module is used for imaging the linear chirped light intensity spatial and temporal distribution signal output by the phase extraction module on the data acquisition module, and includes a first convex lens, a diffractive optical element, a narrow-band filter and a second convex lens arranged in sequence along the light beam transmission direction, and the narrow-band filter is arranged obliquely to the optical axis of the light beam.

[0013] The data acquisition module is used for acquiring the image output by the spectral filtering and frame reading module in a single exposure and transmitting the image to the image processing module.

[0014] The image processing module is used for processing the image output by the data acquisition module, extracting the multi-frame images of the signals at different time points carried by the linear chirped light from the image, and using an X-ray signal inversion algorithm to invert the multi-frame images of the time-varying X-ray signals of the target.

[0015] The synchronization control module is used for the synchronization between the target, the chirped pulse light generating module and the data acquisition module at the picosecond level.

[0016] Further, the chirped pulse light coupling module is a beam splitter.

[0017] The beam splitter reflects linearly chirped pulse light generated by the chirped pulse light generation module and transmits linearly chirped pulse light carrying the spatial and temporal distribution of the refractive index of the chip reflected by the semiconductor chip module.

[0018] Further, an optical fiber is arranged between the beam splitter and the chirped pulse light generation module, one end of the optical fiber is connected to the chirped pulse light generation module, and the other end is coupled to the beam splitter.

[0019] Further, a mirror is arranged between the beam splitter and the chirped pulse light generation module.

[0020] Further, the response time of the semiconductor chip module is in the order of picoseconds.

[0021] The pulse width of the linearly chirped pulse light is in the order of nanoseconds to picoseconds, and the center wavelength is 700nm-850nm.

[0022] In a second aspect, the application also provides an X-ray ultrafast imaging method based on radiation conversion and spectral filtering, which is characterized by comprising the following steps:

[0023] 1) The X-ray coupling module couples the X-ray signal of the target to be imaged on the semiconductor chip module, and the target emits a trigger signal to the synchronization control module, and the synchronization control module emits a first control signal and a second control signal according to the trigger signal;

[0024] 2) The semiconductor chip module converts the X-ray intensity spatial and temporal distribution into the chip refractive index spatial and temporal distribution;

[0025] 3) The chirped pulse light generation module receives the first control signal emitted by the synchronization control module, generates linearly chirped pulse light, and then the linearly chirped pulse light is expanded and collimated by the chirped pulse light coupling module, irradiated to the semiconductor chip module, reflected by the semiconductor chip module, and then enters the phase extraction module after the chirped pulse light coupling module;

[0026] 4) The phase extraction module extracts the chip refractive index spatial and temporal distribution carried by the linearly chirped pulse light into linearly chirped light intensity spatial and temporal distribution information;

[0027] 5) The linearly chirped light intensity spatial and temporal distribution information enters the spectral filtering and frame reading module, is divided into N sub-beams by the first convex lens, and the N sub-beams are incident on the narrow-band filter placed at an angle, and after filtering, the N sub-beams are coupled and imaged on the data acquisition module by the second convex lens.

[0028] Among them, the center wavelengths of different sub-beams are different, carrying signal information at different times, and different sub-beams are imaged on different regions of the detector in the data acquisition module.

[0029] 6) The data acquisition module receives the second control signal sent by the synchronization control module, collects the signal output by the spectral filtering framing reading module within a single exposure, and transmits the collected data to the image processing module, extracts the multi-framing image of the corresponding signal at different times in different regions of the image, and uses the X-ray signal inversion algorithm to invert the time-varying X-ray signal multi-framing image of the target;

[0030] Further, in step 6), the X-ray signal inversion algorithm uses the corresponding relationship between the X-ray intensity, the semiconductor chip refractive index variation, the chirped pulse light phase variation, the phase extraction system intensity variation, and the image intensity variation for inversion.

[0031] Compared with the prior art, the advantages of the present application are:

[0032] The system and method of the present application realize the radiation conversion of the X-ray time-varying signal to the short-wave infrared chirped pulse probe light signal by using a semiconductor chip, and perform spectral filtering framing reading on the chirped pulse probe light. In the case of ensuring picosecond-level time resolution, the number of reconstructed framings can be increased to the order of tens of framings. Since each image is imaged at a different position on the effective image plane of the detector, each image has the advantage of a large dynamic range, and continuous high-sensitivity fine X-ray imaging of dynamic phenomena with a large dynamic range can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is the schematic diagram of the principle structure of the X-ray ultrafast imaging system of the present application based on radiation conversion and spectral filtering;

[0034] Figure 2 is the working principle diagram of the spectral filtering framing reading module in the embodiment of the present application;

[0035] Among them, the reference signs are as follows:

[0036] 101-target, 102-X-ray coupling module, 103-semiconductor chip module, 104-chirped pulse light generating module, 105-chirped pulse light coupling module, 106-mirror, 107-phase extraction module, 108-spectral filtering framing reading module, 109-first convex lens, 110-diffractive optical element, 111-narrowband filter, 112-second convex lens, 113-data acquisition module, 114-image processing module, 115-synchronization control module. DETAILED DESCRIPTION

[0037] The content of the present application is further described in detail below in combination with the drawings and specific embodiments.

[0038] As Figure 1As shown, the present application is based on an X-ray ultrafast imaging system based on radiation conversion and spectral filtering, which comprises an X-ray coupling module 102, a semiconductor chip module 103, a chirped pulse light generation module 104, a chirped pulse light coupling module 105, a phase extraction module 107, a spectral filtering framing reading module 108, a data acquisition module 113, an image processing module 114 and a synchronous control module 115.

[0039] The X-ray coupling module 102 is used to couple the X-ray signal of the target 101 to image on the semiconductor chip module 103.

[0040] The semiconductor chip module 103 is used to detect the X-ray signal of the target 101, and convert the X-ray intensity spatial and temporal distribution into the chip refractive index spatial and temporal distribution; the response time of the semiconductor chip module 103 is in the order of picoseconds.

[0041] The chirped pulse light generation module 104 is used to generate linear chirped pulse light with pulse width in the order of nanoseconds to picoseconds and center wavelength of 700nm-850nm.

[0042] The chirped pulse light coupling module 105 is used to expand and collimate the linear chirped pulse light generated by the chirped pulse light generation module 104, and then irradiate the semiconductor chip module 103, and couple the linear chirped pulse light carrying the chip refractive index spatial and temporal distribution reflected by the semiconductor chip module 103 into the phase extraction module 107.

[0043] The phase extraction module 107 is used to extract the chip refractive index spatial and temporal distribution carried by the linear chirped pulse light into linear chirped light intensity spatial and temporal distribution information.

[0044] The spectral filtering framing reading module 108 is composed of a first convex lens 109, a diffractive optical element 110, a narrow-band filter 111 and a second convex lens 112 arranged in sequence along the light beam transmission direction, and the narrow-band filter 111 is arranged obliquely to the light beam optical axis; the spectral filtering framing reading module 108 is used to frame image the time-varying intensity signal output by the phase extraction module 107 on the data acquisition module 113, and the signals at different times are imaged on different regions of the detector in the data acquisition module 113.

[0045] The data acquisition module 113 is used to acquire the signals output by the spectral filtering framing reading module 108 within a single exposure.

[0046] The image processing module 114 is used to process the image output by the data acquisition module 113, extract the multi-framing images of signals at different times carried by the linear chirped light from the image, and use the X-ray signal inversion algorithm to invert the multi-framing images of time-varying X-ray signals of the target 101.

[0047] The synchronization control module 115 is used for synchronization between the target 101, the chirped pulse light generation module 104 and the data acquisition module 113 at the picosecond level.

[0048] The chirped pulse light coupling module 105 in this embodiment is a beam splitter, which reflects the linear chirped pulse light generated by the chirped pulse light generation module 104 to the semiconductor chip module 103, and transmits the linear chirped pulse light carrying the chip refractive index spatiotemporal distribution reflected by the semiconductor chip module 103 to the phase extraction module 107. In this embodiment, a mirror 106 is arranged between the beam splitter and the chirped pulse light generation module 104, which is used to fold the linear chirped pulse light generated by the chirped pulse light generation module 104 to realize the miniaturization of the system; in other embodiments, an optical fiber is arranged between the beam splitter and the chirped pulse light generation module 104, the incident end of the optical fiber is connected with the chirped pulse light generation module 104, and the outlet end faces the beam splitter, the light beam emitted from the outlet end of the optical fiber is incident on the beam splitter and is emitted to the semiconductor chip module 103 through the beam splitter.

[0049] Based on the above-mentioned X-ray ultrafast imaging system, this embodiment provides an X-ray ultrafast imaging method based on radiation conversion and spectral filtering, which comprises the following steps:

[0050] 1) The X-ray coupling module 102 couples the X-ray signal of the target 101 to image on the semiconductor chip module 103, while the X-ray generating device of the target 101 emits a trigger signal to the synchronization control module 115, the synchronization control module 115 performs clock delay according to the trigger signal and emits a first control signal to the chirped pulse light generation module 104 and a second control signal to the data acquisition module 113 to realize the synchronization between the target 101, the chirped pulse light generation module 104 and the data acquisition module 113;

[0051] 2) The semiconductor chip module 103 converts the X-ray intensity spatiotemporal distribution into the chip refractive index spatiotemporal distribution;

[0052] 3) The chirped pulse light generation module 104 receives the first control signal emitted by the synchronization control module 115, generates linear chirped pulse light with a pulse width in the nanosecond to picosecond order and a center wavelength of 700nm-850nm, the linear chirped pulse light is expanded and collimated by the chirped pulse light coupling module 105, irradiated to the semiconductor chip module 103, reflected by the semiconductor chip module 103, and then enters the phase extraction module 107 through the chirped pulse light coupling module 105;

[0053] 4) The phase extraction module 107 extracts the chip refractive index spatiotemporal distribution carried by the linear chirped pulse light into linear chirped light intensity spatiotemporal distribution information;

[0054] 5) The linearly chirped intensity spatio-temporal distribution information enters the spectral filtering framing reading module 108, and after the first convex lens 109, it is divided into N sub-beams by the diffractive optical element 110. The N sub-beams are incident on the narrow-band filter 111 placed obliquely at different angles. After filtering, the center wavelengths of different sub-beams are different, carrying signal information at different times. Finally, the N sub-beams are coupled and imaged on the data acquisition module 113 by the second convex lens 112, and different sub-beams are imaged on different regions of the detector in the data acquisition module 113.

[0055] 6) The data acquisition module 113 receives the second control signal sent by the synchronization control module 115, collects the signal output by the spectral filtering framing reading module 108 within a single exposure, and transmits the collected data to the image processing module 114 to extract the multi-framing image of the corresponding signal at different times in different regions of the image, and use the X-ray signal inversion algorithm to invert the time-varying X-ray signal multi-framing image of the target 101.

[0056] In step 5), the working principle of the spectral filtering framing reading module 108 is as shown in Figure 2 The size of the object plane in this embodiment is d, the focal length of the first convex lens 109 is f1, the focal length of the second convex lens 112 is f2, the center wavelengths of different sub-beams are λ1, λ2, …, λ n , respectively corresponding to the signals at t1, t2, …, t n , the sub-beams are imaged at different positions of the image plane, and the size of the single image of the image plane is d' = Ad, where A = f2 / f1 is the magnification, and the spacing between adjacent images is Δ.

[0057] In step 6), the X-ray signal inversion algorithm uses the corresponding relationship between the X-ray intensity, the semiconductor chip refractive index change, the chirped pulsed light phase change, the phase extraction system intensity change, and the image intensity change to perform inversion.

[0058] In this embodiment, the semiconductor chip is used to realize the radiation conversion of the X-ray time-varying signal to the short-wave infrared chirped pulsed probe light signal, and the chirped pulsed probe light is read by spectral filtering framing. The beam splitting, narrow-band filtering, and large-array detector imaging are used to ensure the picosecond-level time resolution, and the number of reconstructed frames can be increased to tens of frames. Since each image is imaged at a different position of the effective image plane of the detector, each image has a large dynamic range, which can realize continuous high-sensitivity fine X-ray imaging of large dynamic range dynamic phenomena.

[0059] The above merely describes the preferred embodiments of the present application, and does not limit the technical solutions of the present application thereto, and any variations made by those skilled in the art on the basis of the main technical concepts of the present application shall fall within the technical scope of the present application.

Claims

1. An X-ray ultrafast imaging system based on radiation conversion and spectral filtering, characterized by: The X-ray coupling module (102), the semiconductor chip module (103), the chirped pulse light generation module (104), the chirped pulse light coupling module (105), the phase extraction module (107), the spectral filtering and framing reading module (108), the data acquisition module (113), the image processing module (114) and the synchronous control module (115); The X-ray coupling module (102) is used for coupling X-ray signals of the target (101) to image on the semiconductor chip module (103); The semiconductor chip module (103) is used for detecting the X-ray signals of the target (101) and converting the X-ray intensity space-time distribution into the chip refractive index space-time distribution; The chirped pulse light generation module (104) is used for generating linear chirped pulse light; The chirped pulse light coupling module (105) is used for expanding and collimating the linear chirped pulse light generated by the chirped pulse light generation module (104) and irradiating the semiconductor chip module (103), and coupling the linear chirped pulse light carrying the chip refractive index space-time distribution reflected by the semiconductor chip module (103) into the phase extraction module (107); The phase extraction module (107) is used for extracting the chip refractive index space-time distribution carried by the linear chirped pulse light into linear chirped light intensity space-time distribution information; The spectral filtering and framing reading module (108) is used for imaging the linear chirped light intensity space-time distribution signal output by the phase extraction module (107) on the data acquisition module (113) in frames, and includes a first convex lens (109), a diffractive optical element (110), a narrow-band filter (111) and a second convex lens (112) arranged in sequence along the light beam transmission direction, and the narrow-band filter (111) is arranged obliquely to the optical axis of the light beam, the diffractive optical element (110) is used for dividing the incident light beam into multiple sub-beams and imaging on different regions of the detector in the data acquisition module (113); The data acquisition module (113) is used for collecting the images output by the spectral filtering and framing reading module (108) in a single exposure and transmitting to the image processing module (114); The image processing module (114) is used for processing the images output by the data acquisition module (113), extracting the multi-framing images of the signals at different times carried by the linear chirped light from the images, and using the X-ray signal inversion algorithm to invert the time-varying X-ray signal multi-framing images of the target (101); the X-ray signal inversion algorithm uses the corresponding relationship between the X-ray intensity, the semiconductor chip refractive index change, the chirped pulse light phase change, the phase extraction system intensity change and the image intensity change to perform inversion; The synchronous control module (115) is used for the synchronization between the target (101), the chirped pulse light generation module (104) and the data acquisition module (113) at the picosecond level.

2. The X-ray ultrafast imaging system based on radiation conversion and spectral filtering according to claim 1, characterized in that: The chirped pulse light coupling module (105) is a beam splitter. The beam splitter reflects linearly chirped pulse light generated by the chirped pulse light generation module (104) and transmits linearly chirped pulse light carrying the spatial and temporal distribution of the refractive index of the chip reflected by the semiconductor chip module (103).

3. The radiation conversion and spectral filtering based X-ray ultrafast imaging system of claim 2, wherein: An optical fiber is arranged between the beam splitter and the chirped pulse light generation module (104), one end of the optical fiber is connected to the chirped pulse light generation module (104), and the other end is coupled to the beam splitter.

4. The radiation conversion and spectral filtering based x-ray ultrafast imaging system of claim 2, wherein: A mirror (106) is arranged between the beam splitter and the chirped pulse light generation module (104).

5. The X-ray ultrafast imaging system based on radiation conversion and spectral filtering according to any of claims 1 to 4, characterized in that: The response time of the semiconductor chip module (103) is in the order of picoseconds. The pulse width of the linearly chirped pulse light is in the order of nanoseconds to picoseconds, and the center wavelength is 700nm-850nm.

6. An X-ray ultrafast imaging method based on radiation conversion and spectral filtering, based on the X-ray ultrafast imaging system based on radiation conversion and spectral filtering according to claim 1, characterized in that, The method comprises the following steps: 1) The X-ray coupling module (102) couples the X-ray signal of the target (101) to image on the semiconductor chip module (103), while the target (101) emits a trigger signal to the synchronous control module (115), and the synchronous control module (115) emits a first control signal and a second control signal according to the trigger signal; 2) The semiconductor chip module (103) converts the X-ray intensity spatial and temporal distribution into the chip refractive index spatial and temporal distribution; 3) The chirped pulse light generation module (104) receives the first control signal emitted by the synchronous control module (115), generates linearly chirped pulse light, and then the linearly chirped pulse light is expanded and collimated by the chirped pulse light coupling module (105) and irradiated to the semiconductor chip module (103), and reflected by the semiconductor chip module (103) and enters the phase extraction module (107) after the chirped pulse light coupling module (105); 4) The phase extraction module (107) extracts the chip refractive index spatial and temporal distribution carried by the linearly chirped pulse light into linearly chirped light intensity spatial and temporal distribution information; 5) The linearly chirped light intensity spatial and temporal distribution signal enters the spectral filtering and amplitude reading module (108), is divided into N sub-beams by the diffractive optical element (110) after the first convex lens (109), and the N sub-beams are incident on the narrow-band filter (111) placed at different angles, and the N sub-beams are coupled and imaged on the data acquisition module (113) after filtering by the second convex lens (112); Wherein, the center wavelengths of different sub-beams are different, and different sub-beams carry signal information at different times, and different sub-beams are imaged on different regions of the detector in the data acquisition module (113); 6) The data acquisition module (113) receives the second control signal emitted by the synchronous control module (115), collects the signal output by the spectral filtering and amplitude reading module (108) in a single exposure, and transmits the collected data to the image processing module (114), extracts the multi-amplitude image of the corresponding signal at different times in different regions of the image, and uses the X-ray signal inversion algorithm to invert the time-varying X-ray signal multi-amplitude image of the target (101).

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