CN110887858B - Ultrafast high-energy electron probe system based on ultrafast wide-spectrum electron beam - Google Patents
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Abstract
The invention relates to an ultrafast high-energy electronic probe system based on an ultrafast wide-spectrum electron beam. The system utilizes ultrashort ultrastrong laser generated by a femtosecond laser to be coupled with a target body to generate an ultrafast wide-spectrum electron beam of hundred megaelectron volts, the ultrafast wide-spectrum electron beam passes through a combined magnet module to generate time chirp, and a picosecond ultrafast electron beam with time information is obtained through a femtosecond laser time precise time synchronization system and can be used for an ultrafast electron probe. The invention adopts the ultrafast wide-spectrum high-energy electron beam driven by the femtosecond laser as an electron source, can obtain a picosecond ultrafast high-energy electron probe, realizes the time resolution of the electron beam at the picosecond level, improves the time resolution of an electron probe system, obtains the hundred-megaelectron-volt high-energy electron probe, and has wide application prospect in the aspect of ultrafast electron detection.
Description
Technical Field
The invention relates to the field of ultrafast electronic probes, in particular to an ultrafast high-energy electronic probe system based on ultrafast wide-spectrum electron beams.
Background
The electronic probe is used as a nondestructive detection means with wide application, has the characteristics of high speed, high resolution, high precision and the like, but the diagnosis of an ultrafast process by the electronic probe needs an ultrafast electron beam carrying time information, and meanwhile, for the detection of certain processes, ultrafast electrons with high energy (typical value of 10-100 Mev) are also needed as the electronic probe. The existing electronic probe system is difficult to obtain the picosecond-level and ultra-fast high-energy electronic probe simultaneously.
Disclosure of Invention
The invention aims to provide an ultrafast high-energy electronic probe system based on an ultrafast wide-spectrum electron beam, and aims to solve the problem that an existing electronic probe system is difficult to obtain picosecond-level and ultrafast high-energy electronic probes at the same time.
In order to achieve the purpose, the invention provides the following scheme:
an ultrafast high-energy electron probe system based on an ultrafast wide-spectrum electron beam, the ultrafast high-energy electron probe system comprising: the device comprises a laser drive electronic input system, a femtosecond laser time accurate synchronization system, a combined magnet module, a sample and a separation magnet;
the laser driving electronic input system comprises a femtosecond laser, a light path transmission system and a gas target system which are sequentially arranged; the femtosecond laser generates femtosecond laser pulses with joule level energy; the femtosecond laser pulse is delayed by the optical path transmission system and focused on a target body generated by the gas target body system to generate an ultrafast wide-spectrum electron beam;
the femtosecond laser time precise synchronization system is respectively connected with the femtosecond laser and the gas target body system; the femtosecond laser time precise synchronization system realizes the synchronization of the femtosecond laser pulse and the gas target body system by utilizing a laser trigger signal and provides a time reference of an electronic probe;
the combined magnet module is arranged on an emergent light path of the laser driving electronic input system; the ultrafast wide-spectrum electron beam generated by the laser drive electronic input system enters the combined magnet module; after the ultrafast wide-spectrum electron beam passes through the magnetic field of the combined magnet module, electrons with different energies in the ultrafast wide-spectrum electron beam are separated in time, and a picosecond-level ultrafast electron beam with time information is output;
the sample and the separation magnet are sequentially arranged on an emergent light path of the combined magnet module; the ultrafast electron beam penetrates out of the combined magnet module, enters the sample and then enters the separation magnet from the rear end of the sample; the separation magnet is used for spatially separating the ultrafast electron beam passing through the sample according to different energies and times, so that the split beam analysis of electrons with different energies and different times is realized, and the ultrafast measurement of the electron probe is realized.
Optionally, the ultrafast high-energy electron probe system further comprises a shielding system; the shielding system is installed around the combined magnet module and the separation magnet and is used for shielding X-rays generated in the laser-driven electron acceleration process and the electron migration process.
Optionally, the shielding system is made of lead of a predetermined thickness.
Optionally, the femtosecond laser pulse generated by the femtosecond laser is less than 100fs, and the power is greater than 10 TW.
Optionally, the optical path transmission system includes a pair of mirrors and an off-axis parabolic mirror OAP; the reflecting mirror is used for adjusting time delay; the OAP is used to focus the femtosecond laser pulses.
Optionally, the combined magnet module is formed by three magnets with equal magnetic field sizes arranged side by side.
Optionally, the three magnets with equal magnetic field sizes are respectively a first magnet, a second magnet and a third magnet; the first magnet, the second magnet and the third magnet are sequentially arranged side by side; the first magnet and the third magnet are equal in size and shape, and the magnetic field directions are the same; the magnetic field direction of the second magnet is opposite to that of the first magnet, and the length of the second magnet is twice that of the first magnet.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention discloses an ultrafast high-energy electronic probe system based on an ultrafast wide-spectrum electron beam. The system utilizes ultrashort ultrastrong laser generated by a femtosecond laser to be coupled with a target body to generate a high-energy ultrafast wide-spectrum electron beam, the ultrafast wide-spectrum electron beam passes through a combined magnet module to generate time chirp, and a picosecond-level ultrafast electron beam with time information is obtained through a femtosecond laser time precise time synchronization system and can be used as an ultrafast electron probe. The invention adopts the ultrafast wide-spectrum high-energy electron beam driven by the femtosecond laser as the electron source, can obtain the picosecond ultrafast high-energy electron probe, realizes the picosecond-level time resolution of the electron beam, improves the time resolution of the electron probe system, obtains the high-energy electron probe, and has wide application prospect in the aspect of ultrafast electron detection.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
FIG. 1 is a schematic structural diagram of an ultrafast high-energy electron probe system based on an ultrafast wide-spectrum electron beam according to the present invention;
FIG. 2 is a schematic diagram of an electrical pulse timing sequence for the ultrafast high-energy electron probe system according to the present invention;
description of the symbols: in the figure, 1 is a femtosecond laser, 2 is an optical path transmission system, 3 is a gas target system, 4 is a combined magnet module, 5 is a sample, 6 is a separation magnet, 7 is a shielding system, 401 is a first magnet, 402 is a second magnet, and 403 is a third magnet.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the prior art, ultrafast high-energy electron probes on the picosecond scale are difficult to obtain. The invention aims to provide an ultrafast high-energy electron probe system based on ultrafast wide-spectrum electron beams, aiming at providing a wide-spectrum high-energy electron beam with femtosecond time scale obtained by accelerating femtosecond laser, realizing time separation of electron beams with different energy after passing through a magnet array, obtaining the ultrafast high-energy electron beam with picosecond-level time chirp through an accurate time synchronization system of the femtosecond laser, being capable of being used as an electron probe, separating the electron beams with different energy and time after passing through a subsequent separation magnet, and obtaining energy loss corresponding to the electrons with different energy and time through beam splitting analysis, thereby realizing detection.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
In order to solve the problem that the conventional electronic probe system is difficult to obtain a picosecond-level and ultra-fast high-energy electronic probe at the same time, the invention aims to obtain a femtosecond-level wide-spectrum electron beam with small beam spot and high brightness by using a femtosecond laser-driven wake-wave field electron accelerator. And electrons are accelerated by a plasma wave excited in the plasma by the ultrashort pulse laser. Compared with the traditional electron accelerator, the laser electron wake field accelerator has the advantages of small size, large acceleration gradient and the like, the output electron beam has the characteristics of small beam spot, narrow pulse (femtosecond magnitude), high brightness and the like, meanwhile, electrons generated under certain conditions are naturally wide in energy spectrum, the energy of the electrons can reach thousands of megavolts, and the ultrafast wide-energy-spectrum high-energy electron beam required by the ultrafast electron probe can be provided. Meanwhile, the femtosecond laser can provide accurate time synchronization and provide a foundation for time resolution of subsequent electrons.
Based on the above concept, the present invention provides an ultrafast high-energy electron probe system based on ultrafast wide-spectrum electron beams, as shown in fig. 1, the ultrafast high-energy electron probe system comprising: a laser drive electronic input system, a femtosecond laser time precise synchronization system, a combined magnet module 4, a sample 5, a separation magnet 6 and a shielding system 7.
Referring to fig. 1, the laser driving electronic input system includes a femtosecond laser 1, an optical path transmission system 2 and a gas target system 3, which are sequentially arranged. The femtosecond laser 1 generates femtosecond laser pulses with joule level energy; the femtosecond laser pulse is conducted in a delayed mode through the optical path transmission system 2 and focused on a target body generated by the gas target body system 3. The gas target system 3 is a device that uses nozzles and other means to generate high pressure gas with a specified density profile. The laser and the gas target are coupled and interacted to accelerate electrons to generate a needed femtosecond wide-energy-spectrum electron beam, namely, a high-energy ultrafast wide-spectrum electron beam.
Specifically, the laser-driven electronic input system utilizes an ultrafast wide-spectrum high-energy electron beam generated by accelerating a laser wake field as an electron source to realize electronic input, and the working process is as follows:
the femtosecond laser 1 is used for generating laser pulses with femtosecond-level pulse width and terawatt-level power. The light path transmission system 2 is arranged on an emergent light path of the femtosecond laser 1, and the gas target body system 3 is arranged on the emergent light path of the light path transmission system 2. The optical path transmission system 2 is used for adjusting the time delay of the laser pulse and focusing the laser pulse in a gas area (target body) sprayed by the gas target body system 3. The laser pulse ionizes the gas in the gas area into plasma, the plasma interacts with the plasma, plasma tail waves are excited, accelerated electrons are driven, and high-energy narrow-pulse wide-spectrum electron beams are generated to serve as ultrafast wide-spectrum high-energy electron beams of the ultrafast electron probe system.
The femtosecond laser time accurate synchronization system utilizes a laser trigger signal, generates a delay signal through a signal delay generator, triggers the gas target body system 3 to jet gas to generate a gas target, and simultaneously utilizes the laser trigger signal to provide a time reference for an ultrafast electronic probe signal.
Specifically, the femtosecond laser time precise synchronization system is respectively connected with the femtosecond laser 1 and the gas target body system 3. The femtosecond laser time precise synchronization system realizes the synchronization of the femtosecond laser pulse and the gas target body system 3 by utilizing a laser trigger signal and provides a time reference of an electronic probe.
The combined magnet module 4 is arranged on an emergent light path of the laser driving electronic input system. The ultrafast broad spectrum electron beam generated by the laser-driven electronic input system enters the combined magnet module 4. After the ultrafast wide-spectrum electron beam passes through the magnetic field of the combined magnet module 4, electrons with different energies in the ultrafast wide-spectrum electron beam are separated in time, and a picosecond-level ultrafast electron beam with time information is output.
The sample 5 and the separation magnet 6 are sequentially arranged on an emergent light path of the combined magnet module 4. The ultrafast electron beam penetrates out of the combined magnet module 4, enters the sample 5, and enters the separation magnet 6 from the rear end of the sample 5. The separation magnet 6 is used for spatially separating the ultrafast electron beam passing through the sample 5 according to different energies and times, so that the electrons with different energies and different times are subjected to beam splitting analysis, and the ultra-dynamic measurement of the electron probe is realized.
The shielding system 7 is installed around the combined magnet module 4 and the separating magnet 6, and is used for shielding X-rays generated by the laser-driven electron acceleration process and the electron migration process.
Specifically, the femtosecond laser 1 is intended to provide laser pulses with femtosecond-level pulse width and terawatt-level power, and the femtosecond laser pulses generated by the femtosecond laser are generally less than 100fs and more than 10TW in power. In the present embodiment, the femtosecond laser 1 supplies laser pulses of 25fs, an output power of 200TW, and a repetition rate of 5 Hz.
The optical path transmission system 2 is composed of optical devices such as a reflector and an OAP (Off-Axis Parabolic Mirror), and aims to adjust proper time delay and well focus laser on a gas target. In this embodiment, the laser is focused at the gas target location by an OAP of 1 meter focal length.
The optical path transmission system 2 is designed individually according to each system, for example, some systems need more mirrors to change the layout of the optical path, perform optical path climbing, or add an auxiliary optical path (analog optical path, far-near field, etc.) in the optical path. The necessary elements in the optical path of the optical path transmission system 2 are a pair of mirrors for adjusting the delay time, that is, the optical path length is changed by changing the interval of the pair of parallel mirrors, and an OAP for focusing the laser light. The order of the OAP and the reflector pair in the optical path is not fixed, and is determined by the specific optical path design.
The gas target system 3 is controlled by a nozzle (or other gas pulse control system) connected with a high-pressure gas cylinder, a gas valve, a flow controller and other components through time delay to spray high-pressure gas (nitrogen, helium, mixed gas and the like) with proper density at proper time and form certain density distribution. Wherein the proper density distribution is controlled by designing the nozzle, the gas pressure determines the whole density, and the gas pressure can be controlled by a flow controller and a gas valve. When the laser power is too high, the nozzle and the light path are both arranged in a vacuum environment, the laser is focused by the OAP, and the nozzle is controlled to be close to the focal position of the laser, so that the laser can be focused in the sprayed gas area. The relative position of the laser focusing point and the gas can be changed by changing the position of the gas nozzle without changing the laser focusing position.
The laser emitted from the optical path transmission system 2 is focused in the gas area sprayed out by the gas target body system 3, the gas is ionized into plasma, the plasma interacts with the plasma, the plasma tail wave is excited, accelerated electrons are driven, high-energy narrow-pulse wide-spectrum electron beams are generated, and the pulse width of the generated electrons is in the femtosecond level. By changing the doping ratio, the gas pressure and the laser focusing position of the selected gas, the cut-off energy, the energy dissipation and the electric quantity of generated electrons can be adjusted.
In this embodiment, the target gas is helium doped with 0.5% nitrogen, the gas pressure is 40bar, the target gas is ejected through a nozzle with a length of 10mm, and the target gas interacts with the laser to generate an ultrafast high-energy wide-spectrum electron beam with a cut-off energy of 200MeV, a full-energy electric quantity of 200pC and a duration of 20 fs.
In this embodiment, the gas target system includes a high pressure gas cylinder, a gas valve, a flow controller, and a nozzle. The high-pressure gas cylinder is connected with the nozzle through a gas pipe, the gas valve is arranged on the gas pipe, and the flow controller is connected with the gas valve and used for controlling the gas flow; the air valve is also connected with a signal delay generator of the femtosecond laser time accurate synchronization system and used for generating a delay signal according to the signal delay generator to control the delayed opening and closing of the air valve.
The femtosecond laser time accurate synchronization system utilizes a laser trigger signal to generate a delay signal through a signal delay generator, and triggers the gas target body system 3 to jet gas to generate a gas target; meanwhile, the laser trigger signal is utilized to realize synchronization and calibration for the ultrafast electronic probe signal.
The femtosecond laser time precise synchronization system realizes system precise time synchronization by using the femtosecond laser trigger signal and obtains time information of the output electronic probe by using the femtosecond laser trigger signal. The method specifically comprises the following steps:
the time of the femtosecond laser trigger signal plus the delay (laser optical path, time of electron generated by interaction between the laser beam and the gas target, and flight time of electron beam moving to the entrance of the combined magnet module) is the time reference of the electron probe, and plus the flight time (obtained by calculation) of electron beams with different energy in the combined magnet module is the time information of the electron probe.
The combined magnet module 4 realizes the time separation of electron beams with different energy in the ultrafast wide-spectrum high-energy electron beam by using the combination of a plurality of magnets, so that the whole electron beam has picosecond-level time chirp after passing through the combined magnet module. When the electron energy spectrum and the magnetic field distribution are known, the time information of the probe electron beam can be obtained through a precise time synchronization system. The time distribution of the probe electron beam can be changed by adjusting the electron energy spectrum and the magnetic field distribution.
Specifically, the combined magnet module 4 is formed by three magnets with equal magnetic field sizes arranged side by side, wherein the size of the first magnet is completely equal to that of the third magnet; the magnetic field intensity of the second magnet is the same as that of the other two magnets, the direction of the magnetic field is opposite to that of the other two magnets, and the length of the second magnet is twice that of the other two magnets along the electron input direction (x direction); three magnets are closely attached.
Specifically, the three magnets with the same magnetic field are the first magnet 401, the second magnet 402, and the third magnet 403. Wherein the first magnet 401, the second magnet 402 and the third magnet 403 are placed side by side in this order. The first magnet 401 and the third magnet 403 have the same size and the same shape, and the magnetic field directions are the same. The magnetic field direction of the second magnet 402 is opposite to the magnetic field direction of the first magnet 401 and the third magnet 403, and the length of the second magnet 402 in the electron input direction is twice the length of the first magnet 401 and the third magnet 403.
As shown in fig. 1, in this embodiment, a narrow pulse width and wide spectrum electron beam obtained by accelerating electrons in a laser wake field enters a magnetic field of the first magnet 401 along an x-axis direction, the magnetic field is along a y-axis direction, a motion trajectory of the electron beam is shifted along a z-axis direction and forms an included angle with the x-axis under the action of the y-direction magnetic field, and the electron shift is larger when the energy is lower, so that the electron beam is sequentially arranged along the z-axis according to the difference of the energy. The magnetic field of the second magnet 402 is opposite to the first magnet 401 and has the same magnitude, and after the electron beam enters the second magnet 402, the electron beam is spatially separated first and then converged, and is temporally separated further. Finally, the electron beam enters the third magnet 403, and due to the design of the symmetric magnetic field, the electrons are spatially converged and symmetrically emitted in the incident direction, but different delays are generated in time according to different energies, so that a high-energy wide-energy-spectrum electron beam with time chirp is obtained. That is, the electron beams enter the third magnet 403 to achieve the coincidence in space, and the electrons with different energies correspondingly obtain different delays in time, so as to obtain a high-energy electron beam with the coincidence in space and different delays in time according to the energy difference. Through the structure, wide-spectrum electrons input by laser are separated in time, time and energy information of output ultrafast electronic pulses can be obtained through known input electronic spectrum, time and position information, the time distribution of the ultrafast electronic pulses can be controlled to a certain degree by adjusting the magnetic field intensity of the electromagnet, the space-time conversion of the ultrafast electronic pulses is realized, and meanwhile, high-energy electron beams with time information and picosecond time delay are output.
For a magnetic field strength of B and a kinetic energy of E1、E2The two beams of electrons, after passing through the combined magnet module 4 with length L in the x direction, have a time delay of:
wherein E is2＝E1+ Δ E, Δ E as two beams of electrons E1、E2The kinetic energy difference of (2).Δ t means the kinetic energy is E1、E1The time delay between the two electrons of + Δ E. m iseQ is the electron mass, B is the electron electric quantity, B is the magnetic field strength, L is the length of the combined magnet module 4 in the x direction, and R is the radius of motion of electrons in the uniform magnetic field.
And c is the speed of light.
FIG. 2 is a schematic diagram of an electrical pulse timing sequence of the ultrafast high-energy electron probe system according to the present invention. As shown in fig. 2, the energy is E1And E2The two beams of electrons arrive at the entrance of the combined magnet module 4 at the same time, but at different times, specifically at the exit E1Electron beam at t0Is reached at t1Then reaches the outlet; and E2Electron beam at t0Is reached at t1+ Δ t to the outlet, and E1The electron beam produces a delay of deltat. It is shown that with the combined magnet module 4 of the present invention, electrons of different energies can be separated in time.
In this embodiment, the electromagnet is selected to form a magnetic field with a length of 20cm in the x-axis direction and a length of 10cm in the y-axis direction, the magnetic field area is an approximately uniform magnetic field with a magnetic induction intensity of 1T, two adjacent magnets are closely attached, and the gap between the two magnets is ignored.
In this case, electrons with energy difference of every 100MeV after passing through the magnet array module (including the combined magnet module 4 and the split magnet 6) will spatially generate a distance of 3mm in the z-axis and a delay of 6ps in time. Under the condition of known magnetic field distribution and electronic energy spectrum, a beam of ultrafast electronic beam column with known time information can be obtained through a femtosecond laser time precise synchronization system. The method specifically comprises the following steps: the time of the femtosecond laser trigger signal plus the delay (laser optical path, time of electron generated by interaction between the laser beam and the gas target, and flight time of electron beam moving to the entrance of the combined magnet module 4) is the time reference of the electron probe, plus the flight time (obtained by calculation) of electron beams with different energy in the combined magnet module 4 is the time information of the electron probe.
As shown in fig. 1, the shielding system 7 is installed around the magnet array module, including but not limited to the portion at the magnet entrance except the electron entrance, the portion at the magnet exit without the electron exit, and the surrounding direction. The shielding system 7 is made of lead with a certain thickness and is intended to protect the operator and the subsequent probe application devices from x-rays generated during the acceleration of the electrons in the laser wake and during the deflection of the electrons.
The ultrafast electron beam passes through the shielding hole of the shielding system 7, enters the sample 5, and enters the separation magnet 6 from the rear end of the sample 5. The separating magnet 6 is composed of an electromagnet, and aims to separate electrons with different energy and time again on the space, so that the back end can conveniently carry out beam splitting collection and analysis on the electrons.
The high-energy electron beams emitted from the combined magnet module 4 pass through the separating magnet 6 after passing through the sample 5, and are sequentially arranged in space according to the energy level of the magnetic field, namely, the electron beams with different energies separated in time and space can be obtained after passing through the separating magnet 6.
Because the combined magnet module 4 enables the electron beam to have corresponding chirp according to the energy level in time, for the ultrafast electron pulse, electrons with different energy correspond to different time and different positions, and after the magnet 6 is separated, the electrons with different energy and different time can be subjected to beam splitting analysis, so that the ultrafast measurement of the electron probe is realized.
The invention provides an ultrafast high-energy electron probe system based on ultrafast wide-spectrum electron beams, which utilizes a femtosecond laser to generate femtosecond laser pulses with joule level energy, and focuses the femtosecond laser pulses on a target body generated by a gas target body system through a light path transmission system to generate high-energy ultrafast wide-spectrum electron beams. The femtosecond laser time precise synchronization system realizes precise synchronization by using a laser trigger signal. The laser drives the electron beam generated by the electron input system to enter the magnet array module, electrons with different energies are separated in time after passing through a magnetic field, under the condition that the input electron energy spectrum, time and position are known, time and space information of the output ultrafast electron pulse can be obtained, the time distribution of the ultrafast electron pulse can be controlled to a certain degree by adjusting the magnetic field intensity of the electromagnet, controllable time chirp is added to the ultrafast electron pulse, and a picosecond-level ultrafast electron beam with time information is output; the shielding system is composed of lead with a certain thickness and is used for shielding X rays generated in the laser-driven electron acceleration process and the electron migration process and weakening the influence of the X rays on an operator and a rear-end electronic probe application device. The separating magnet is used for spatially separating the electron beam passing through the sample according to different energies and time, so that the electrons with different energies and different times are subjected to beam splitting analysis, the ultra-dynamic measurement of the electron probe is realized, and the ultra-fast electron probe with high energy and picosecond-level time chirp can be obtained.
The invention utilizes femtosecond laser to drive the electron accelerator, obtains a compact high-energy ultrafast electron probe system, and overcomes the technical defects that the prior related technology is difficult to obtain a high-energy (hundred megaelectron volts) electron probe and realize picosecond time resolution by utilizing the electron probe.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (6)
1. An ultrafast high-energy electron probe system based on an ultrafast wide-spectrum electron beam, comprising: the device comprises a laser drive electronic input system, a femtosecond laser time accurate synchronization system, a combined magnet module, a sample and a separation magnet;
the laser driving electronic input system comprises a femtosecond laser, a light path transmission system and a gas target system which are sequentially arranged; the femtosecond laser generates femtosecond laser pulses with joule level energy; the femtosecond laser pulse is delayed by the optical path transmission system and focused on a target body generated by the gas target body system to generate an ultrafast wide-spectrum electron beam;
the femtosecond laser time precise synchronization system is respectively connected with the femtosecond laser and the gas target body system; the femtosecond laser time precise synchronization system realizes the synchronization of the femtosecond laser pulse and the gas target body system by utilizing a laser trigger signal and provides a time reference of an electronic probe;
the combined magnet module is arranged on an emergent light path of the laser driving electronic input system; the ultrafast wide-spectrum electron beam generated by the laser drive electronic input system enters the combined magnet module; after the ultrafast wide-spectrum electron beam passes through the magnetic field of the combined magnet module, electrons with different energies in the ultrafast wide-spectrum electron beam are separated in time, and a picosecond-level ultrafast electron beam with time information is output;
the sample and the separation magnet are sequentially arranged on an emergent light path of the combined magnet module; the ultrafast electron beam penetrates out of the combined magnet module, enters the sample and then enters the separation magnet from the rear end of the sample; the separation magnet is used for spatially separating the ultrafast electron beam passing through the sample according to different energies and times, so that the split beam analysis of electrons with different energies and different times is realized, and the ultra-dynamic measurement of the electron probe is realized;
the optical path transmission system comprises a pair of reflectors and an off-axis parabolic mirror OAP; the reflecting mirror is used for adjusting time delay; the OAP is used to focus the femtosecond laser pulses.
2. The ultrafast high-energy electron probe system of claim 1, further comprising a shielding system; the shielding system is installed around the combined magnet module and the separation magnet and is used for shielding X-rays generated in the laser-driven electron acceleration process and the electron migration process.
3. The system of claim 2, wherein the shielding system is comprised of a predetermined thickness of lead.
4. The ultrafast high-energy electron probe system of claim 1, wherein the femtosecond laser generates the femtosecond laser pulses with less than 100fs and more than 10TW in power.
5. The ultrafast high-energy electron probe system of claim 1, wherein the combined magnet module is formed by three magnets with equal magnetic field in parallel.
6. The ultrafast high-energy electron probe system of claim 5, wherein the three magnets with equal magnetic field are a first magnet, a second magnet and a third magnet; the first magnet, the second magnet and the third magnet are sequentially arranged side by side; the first magnet and the third magnet are equal in size and shape, and the magnetic field directions are the same; the magnetic field direction of the second magnet is opposite to that of the first magnet, and the length of the second magnet is twice that of the first magnet.
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| CN113884446B (en) * | 2021-09-27 | 2024-04-26 | 西南石油大学 | Three-phase reaction tank for ultrafast spectrum working condition experiment |
| CN114486961A (en) * | 2022-01-25 | 2022-05-13 | 上海交通大学 | Multi-energy-section easily-controlled ultrafast electron diffraction device |
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| US7755068B2 (en) * | 2004-12-22 | 2010-07-13 | Fox Chase Cancer Center | Laser-accelerated proton therapy units and superconducting electromagnet systems for same |
| CN101435785A (en) * | 2008-12-20 | 2009-05-20 | 中国科学院西安光学精密机械研究所 | Multipurpose ultrafast electron diffraction device |
| WO2011093285A1 (en) * | 2010-02-01 | 2011-08-04 | 国立大学法人京都大学 | Ultrafast electron diffraction device |
| CN102661908B (en) * | 2012-04-27 | 2013-12-25 | 中国科学院上海光学精密机械研究所 | Single-beam femtosecond probe for diagnosing laser plasma parameters |
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