Space-time resolution high-temperature large-energy superthermal electron diagnosis method and device

Abstract

The invention discloses a time-space resolution high-temperature large-energy super-thermal electron diagnosis method and device, a super-thermal electron source bombards a metal target to generate tough-induced radiation, the tough-induced radiation passes through a front filter disc and micro pinholes in a pinhole array plate and then reaches a fluorescent sheet, most X-rays pass through the fluorescent sheet after being filtered and attenuated, and the X-rays are transmitted continuously; part of the X-rays interact with the fluorescent sheet to generate fluorescent light emitted in all directions, a detector with time response is installed to collect and record the fluorescent light and filter the soft fluorescent light through the rear filter disc, and an imaging filter disc and an imaging recording surface are installed in the transmission direction to record spatial distribution of the transmitted X-rays. And fitting the temperature and energy of the superthermal electrons by combining the total fluorescence intensity and the total intensity channel response function of the transmitted X-ray, and reversely deducing the time-space behavior of the superthermal electrons according to the time behavior of the fluorescence signal and the space distribution behavior of the transmitted X-ray. According to the invention, the temperature, energy, time behavior and spatial distribution of the superthermal electrons can be diagnosed at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of superhot electron diagnosis, and in particular to a method and device for time-space resolved high-temperature and high-energy superhot electron diagnosis. Background Art

[0002] High-temperature, high-energy superhot electrons are a common energy source in the field of high-energy-density physics. They have many applications, but also many hazards. In terms of application, for example, high-temperature, high-energy superhot electron beams can be used as a driving source to interact with metal materials to produce X-ray radiation; in terms of hazards, for example, in laser-driven inertial fusion, high-temperature, high-energy superhot electrons may preheat the target capsule and reduce compression efficiency.

[0003] In order to evaluate the efficiency of high-temperature, large superhot electrons in generating X-ray radiation and to assess the extent to which preheating reduces the compression efficiency, it is necessary to have sufficient information on the temperature, energy, temporal behavior and spatial distribution of the superhot electrons.

[0004] Existing superthermal electron diagnostic methods include electron magnetic spectrometry, filter fluorescence spectrometry, filter stack spectrometry, hard X-ray imaging, etc. The electron magnetic spectrometry uses a magnetic field to measure the electron energy spectrum, which has neither time resolution nor spatial resolution; although the filter fluorescence spectrometry has time resolution, it does not have spatial resolution characteristics; compared with the electron magnetic spectrometry, the filter stack method has the advantage of being able to measure superthermal electric temperature and capacity in a closed configuration, but it also does not have time and space resolution; hard X-ray imaging has spatial resolution, but not time resolution.

[0005] In summary, there is currently a lack of a superthermal electron diagnostic method and device with both temporal and spatial resolution. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a high-temperature, high-energy superhot electron diagnostic method and device with time and space resolution, which can obtain the temperature and energy of superhot electrons while having both time resolution and space resolution, so as to better evaluate the characteristics of the radiation source generated by superhot electrons and the degree of harm of superhot electrons.

[0007] In order to solve the above technical problems, the present invention provides a technical solution: a time-space resolved high-temperature and high-energy ultra-hot electron diagnostic method, comprising the following steps:

[0008] S1. The super-hot electron source to be tested interacts with the metal target to generate isotropic bremsstrahlung radiation;

[0009] S2. Place a pinhole array plate in any direction, with the pinhole array plate facing the metal target material. At the same time, each pinhole on the pinhole array plate is filled with materials of different thicknesses and materials as a front filter. The bremsstrahlung generated on the metal target will filter out the low-energy part after passing through the pinhole array plate, and form a pinhole image. Each pinhole has its own imaging path.

[0010] S3. Place a piece of metal material as a fluorescent sheet on the imaging path of each pinhole. The fluorescent sheet and the imaging path of the pinhole form an angle of 45°±5°, so that the X-ray in the transmission direction and the X-ray in the reflection direction are nearly perpendicular to each other, and the X-ray passing through the pinhole array plate interacts with the fluorescent sheet to generate fluorescence;

[0011] S4. Place rear filters of different materials and thicknesses on the reflected light path of each fluorescent sheet to filter out the low-energy part of the fluorescence;

[0012] S5, using a detector with time response to measure the fluorescence filtered by the rear filter to obtain the intensity of the fluorescence;

[0013] S6. Place an X-ray imaging recording surface on the transmission light path of each fluorescent sheet to the X-ray, and select an imaging filter with different thickness or material before the imaging recording surface according to the needs;

[0014] S7. According to S3-S6, define the two channels corresponding to each pinhole as a channel in the reflection direction and a channel in the transmission direction. Each channel will have a different response function due to different filter configurations and detectors. Obtain the channel response function corresponding to each pinhole through theoretical calculation and calibration.

[0015] S8. Fit the temperature and energy of the superhot electrons according to the response function and the measured signal to obtain the temperature and energy of the superhot electrons; at the same time, analyze the spatiotemporal characteristics of the superhot electrons according to the results of the detector with time response and the imaging results with spatial resolution.

[0016] The present invention also provides a high-temperature and high-energy super-hot electron diagnostic device with time and space resolution, comprising a super-hot electron source, a metal target, bremsstrahlung, a front filter, a pinhole array plate, a fluorescent sheet, a rear filter, a detector with time response, an imaging filter, and an imaging recording surface;

[0017] The superthermal electron source bombards the metal target to generate bremsstrahlung radiation. The pinhole array plate is provided with a plurality of micro pinholes. The front filter is arranged on the micro pinholes. The bremsstrahlung radiation reaches the inclined fluorescent sheet after being filtered by the front filter and the micro pinholes. The detector with time response is arranged in the vertical direction of the fluorescent sheet. The rear filter is arranged in front of the detector with time response. The bremsstrahlung radiation part interacts with the fluorescent sheet to generate fluorescence emitted in all directions. The detector with time response collects and records the fluorescence. The imaging filter is arranged in the transmission direction of the fluorescent sheet. The imaging recording surface is arranged on the rear side of the imaging filter. The bremsstrahlung radiation part passes through the fluorescent sheet and continues to propagate forward through the imaging filter to reach the imaging recording surface. The imaging recording surface records the spatial distribution of the bremsstrahlung radiation after transmission.

[0018] The advantages of the present invention compared with the prior art are:

[0019] 1. The present invention can simultaneously diagnose the temperature, energy, time behavior and spatial distribution of superhot electrons;

[0020] 2. The present invention is expected to achieve higher spatial resolution for the diagnosis of the spatial distribution of superhot electrons by selecting a smaller pinhole;

[0021] 3. The present invention is expected to achieve higher time resolution in diagnosing the time behavior of superhot electrons by selecting a detector with faster time response;

[0022] 4. The present invention can realize the diagnosis of the spatial distribution of superhot electrons at different temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a time-space resolved high-temperature and high-energy ultra-hot electron diagnostic device of the present invention.

[0024] As shown in the figure: 1. Superthermal electron source, 2. Metal target, 3. Bremsstrahlung, 4. Front filter, 5. Pinhole array plate, 6. Fluorescent film, 7. Rear filter, 8. Detector with time response, 9. Imaging filter, 10. Imaging recording surface. DETAILED DESCRIPTION

[0025] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “inside”, “outside”, “vertical” and “circumferential” are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] The following is a further detailed description of a time-space resolved high-temperature, high-energy, ultra-hot electron diagnostic method and device of the present invention in conjunction with the accompanying drawings.

[0028] Combined with Figure 1 , the time-space resolved high-temperature, high-energy ultra-hot electron diagnostic device of the present invention is introduced in detail.

[0029] A high-temperature and high-energy super-thermal electron diagnostic device with time and space resolution, comprising a super-thermal electron source 1, a metal target 2, bremsstrahlung 3, a front filter 4, a pinhole array plate 5, a fluorescent sheet 6, a rear filter 7, a detector with time response 8, an imaging filter 9, and an imaging recording surface 10;

[0030] The superthermal electron source 1 bombards the metal target 2 to generate bremsstrahlung 3, i.e., X-rays (X-rays). A plurality of micro pinholes are provided on the pinhole array plate 5. The front filter 4 is arranged on the micro pinholes. The bremsstrahlung 3 reaches the inclined fluorescent sheet 6 after being filtered by the front filter 4 and the micro pinholes. The detector 8 with time response is arranged in the vertical direction of the fluorescent sheet 6. The rear filter 7 is arranged in front of the detector 8 with time response. Part of the bremsstrahlung 3 interacts with the fluorescent sheet 6 to generate fluorescence emitted in all directions. The detector 8 with time response collects and records the fluorescence. The imaging filter 9 is arranged in the transmission direction of the fluorescent sheet 6. The imaging recording surface 10 is arranged on the rear side of the imaging filter 9. Part of the bremsstrahlung 3 passes through the fluorescent sheet 6 and continues to propagate forward through the imaging filter 9 to reach the imaging recording surface 10. The imaging recording surface 10 records the spatial distribution of the bremsstrahlung 3 after transmission.

[0031] The specific implementation process of the time-space resolved high-temperature and high-energy ultra-hot electron diagnostic method and device of the present invention is as follows:

[0032] Example 1

[0033] A time-space resolved high-temperature and high-energy ultra-hot electron diagnostic method comprises the following steps:

[0034] In the first step, the superhot electron source to be tested interacts with a metal target with a higher atomic number to generate isotropic bremsstrahlung. The material of the metal target includes but is not limited to metal materials or alloys with a larger atomic number such as gold, tantalum, uranium, and bismuth. The thickness of the metal target is between 3 microns and 200 microns. The size of the metal target should ensure that all superhot electrons can be collected. The bremsstrahlung emission spectrum generated when the metal target meets the above premise interacts with the superhot electrons satisfies the following formula:

[0035] I(keV / keVsr)=5.11×10 11 Z * E hot / 79 / 4πexp(1-hν / T hot )

[0036] Where I is the emission intensity in keV / keVsr, Z * is the atomic number of the metal target material, E hot and T hot are the energy and temperature of the superhot electrons, h is Planck's constant, and ν is the photon energy.

[0037] Theoretically, the hard X-ray energy spectrum can be used to fit the temperature and energy of superhot electrons, and the time and space distribution of hard X-rays can reflect the time and space distribution of superhot electrons.

[0038] The second step is to place a pinhole array plate in any direction. The pinhole array plate needs to face the metal target material. At the same time, each pinhole on the pinhole array plate needs to be filled with (or attached to the front or rear surface of the pinhole) materials of different thicknesses and materials as the front filter. The material of the pinhole plate itself includes but is not limited to metals with higher atomic numbers such as gold, tantalum, and tungsten. The thickness of the pinhole array plate is between 0.5 mm and 5 mm; the size of the pinhole should be much smaller than the size of the metal target. Specifically, the pinhole size (here refers to the diameter of the circular pinhole or the diagonal of the square pinhole) can be selected between 10 microns and 500 microns. The bremsstrahlung generated on the metal target will filter out the low-energy part (the highest energy of the low-energy part is related to the material and thickness of the filter) after passing through the pinhole array plate, and form a pinhole image. Each pinhole has its own imaging path.

[0039] Step 3: Place a piece of metal material as a fluorescent sheet on the imaging path of each pinhole. The fluorescent sheet forms an angle of 45°±5° with the imaging path of the pinhole, so that the X-rays in the transmission direction and the X-rays in the reflection direction are nearly perpendicular to each other. Since X-rays have strong penetrability, most of the X-rays will pass through the fluorescent sheet, and a small part of the X-rays will interact with the fluorescent sheet to produce fluorescence. The efficiency of producing fluorescence is related to the energy spectrum of the transmitted X-rays and the material and thickness of the fluorescent sheet.

[0040] Step 4: Place rear filters of different materials and thicknesses on the reflected light path of X-rays from each fluorescent film to filter out the low-energy part of the fluorescence.

[0041] Step 5: Use a detector with time resolution function to measure the fluorescence filtered by the rear filter to obtain the intensity of the fluorescence. Detectors with time resolution function include but are not limited to scintillators, etc. The response time of detectors with time response is between tens of femtoseconds and hundreds of picoseconds.

[0042] Step 6: Place an X-ray imaging recording surface on the transmission light path of each fluorescent film to the X-ray. Add imaging filters of different thickness or materials before the recording surface according to needs. The imaging recording surface includes but is not limited to imaging plates, CCDs, etc. The energy spectrum range of the imaging recording surface's response to X-rays is between several kiloelectronvolts and tens of megaelectronvolts.

[0043] Step 7: According to the characteristics of steps 3 to 6, define the two channels corresponding to each pinhole as the channel in the reflection direction and the channel in the transmission direction. Each channel will have a different response function due to different filter configurations and detectors. The channel response function corresponding to each pinhole is obtained through theoretical calculation and calibration. It should be noted that the response functions in the transmission direction and the reflection direction are established in different ways because the detectors and measurement principles are different.

[0044] Step 8: Fit the temperature and energy of superhot electrons according to the response function and the measured signal to obtain the temperature and energy of superhot electrons; at the same time, analyze the spatiotemporal characteristics of superhot electrons according to the results of the detector with time response and the imaging results with spatial resolution.

[0045] The temperature range of the present invention for measuring superhot electrons needs to be no less than 5 kiloelectronvolts, and the energy range needs to be no less than 0.1 joules.

[0046] Example 2

[0047] A high-temperature, high-energy super-hot electron diagnostic device with time and space resolution, when in use, a super-hot electron source bombards a thick Au sheet (metal target) to generate bremsstrahlung 3, which is filtered by a front filter 4 and reaches a fluorescent sheet 6 after being filtered and attenuated by micro-pinholes on a pinhole array plate 5. Most of the X-rays continue to propagate forward through the fluorescent sheet 6, and part of them interact with the fluorescent sheet 6 to generate fluorescence emitted in all directions. A detector 8 with time response is installed in a nearly vertical direction to collect and record the fluorescence, and a rear filter 7 is added before the detector to filter the soft-energy fluorescence. An imaging filter 9 and an imaging recording surface 10 are installed in the transmission direction to record the spatial distribution of the transmitted X-rays. The super-hot electron temperature and energy are fitted by combining the total fluorescence intensity (time-integrated total intensity) and the total intensity (space-integrated total intensity) channel response function of the transmitted X-ray, and the time and space behavior of the super-hot electrons is inferred based on the time behavior of the fluorescence signal and the spatial distribution behavior of the transmitted X-rays.

[0048] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A time-space resolved high-temperature, high-energy, ultra-hot electron diagnostic method, characterized by: The following steps are included: S1. The super-hot electron source to be tested interacts with the metal target to generate isotropic bremsstrahlung radiation; S2. Place a pinhole array plate in any direction, with the pinhole array plate facing the metal target material. At the same time, each pinhole on the pinhole array plate is filled with materials of different thicknesses and materials as a front filter. The bremsstrahlung generated on the metal target will filter out the low-energy part after passing through the pinhole array plate, and form a pinhole image. Each pinhole has its own imaging path. S3. Place a piece of metal material as a fluorescent sheet on the imaging path of each pinhole. The fluorescent sheet and the imaging path of the pinhole form an angle of 45°±5°, so that the X-ray in the transmission direction and the X-ray in the reflection direction are nearly perpendicular to each other, and the X-ray passing through the pinhole array plate interacts with the fluorescent sheet to generate fluorescence; S4. Place rear filters of different materials and thicknesses on the reflected light path of each fluorescent sheet to filter out the low-energy part of the fluorescence; S5, using a detector with time response to measure the fluorescence filtered by the rear filter to obtain the intensity of the fluorescence; S6. Place an X-ray imaging recording surface on the transmission light path of each fluorescent sheet to the X-ray, and select an imaging filter with different thickness or material before the imaging recording surface according to the needs; S7. According to S3-S6, define the two channels corresponding to each pinhole as a channel in the reflection direction and a channel in the transmission direction. Each channel will have a different response function due to different filter configurations and detectors. Obtain the channel response function corresponding to each pinhole through theoretical calculation and calibration. S8. Fit the temperature and energy of the superhot electrons according to the response function and the measured signal to obtain the temperature and energy of the superhot electrons; at the same time, analyze the spatiotemporal characteristics of the superhot electrons according to the results of the detector with time response and the imaging results with spatial resolution.

2. A time-space resolved high-temperature, high-energy, ultra-hot electron diagnostic method according to claim 1, characterized in that: The metal target is made of materials with higher atomic numbers, specifically gold, tantalum, uranium, and bismuth; the thickness of the metal target is between 3 microns and 150 microns, and the size of the metal target should ensure that all superhot electrons can be collected.

3. A time-space resolved high-temperature, high-energy, ultra-hot electron diagnostic method according to claim 2, characterized in that: The bremsstrahlung emission spectrum generated when the metal target interacts with the superhot electrons satisfies the following formula: I(keV / keVsr)=5.11×10 11 Z * IN hot / 79 / 4πexp(1-hν / T hot ) Where I is the emission intensity in keV / keVsr, Z * is the atomic number of the metal target material, E hot is the energy of the superhot electron, T hot is the temperature of the superhot electron, h is Planck's constant, and ν is the photon energy.

4. A time-space resolved high-temperature, high-energy, ultra-hot electron diagnostic method according to claim 3, characterized in that: In step S2, the front filter is filled into each pinhole on the pinhole array plate or attached to the front of the pinhole or to the rear surface of the pinhole.

5. A time-space resolved high-temperature, high-energy, ultra-hot electron diagnostic method according to claim 4, characterized in that: The material of the pinhole array plate itself includes gold, tantalum, and tungsten. The thickness of the pinhole array plate is between 0.5 mm and 5 mm. The size of the pinholes is between 10 microns and 500 microns.

6. A time-space resolved high-temperature, high-energy, superhot electron diagnostic method according to claim 5, characterized in that: In step S5, the response time of the detector with time response is between tens of femtoseconds and hundreds of picoseconds, and the detector with time response includes a scintillator.

7. A time-space resolved high temperature and high energy superhot electron diagnostic method according to claim 6, characterized in that: In step S6, the energy spectrum of the imaging recording surface in response to X-rays ranges from several kiloelectronvolts to tens of megaelectronvolts, and the imaging recording surface includes an imaging plate and a CCD.

8. A time-space resolved high temperature and high energy superhot electron diagnostic method according to claim 7, characterized in that: The temperature range of the superhot electrons is not less than 5 kiloelectron volts, and the energy range is not less than 0.1 joules.

9. A high-temperature and high-energy ultra-hot electron diagnostic device with time and space resolution, characterized in that: It includes an ultra-thermal electron source, a metal target, bremsstrahlung, a front filter, a pinhole array plate, a fluorescent sheet, a rear filter, a detector with time response, an imaging filter, and an imaging recording surface; The superthermal electron source bombards the metal target to generate bremsstrahlung radiation. The pinhole array plate is provided with a plurality of micro pinholes. The front filter is arranged on the micro pinholes. The bremsstrahlung radiation reaches the inclined fluorescent sheet after being filtered by the front filter and the micro pinholes. The detector with time response is arranged in the vertical direction of the fluorescent sheet. The rear filter is arranged in front of the detector with time response. The bremsstrahlung radiation part interacts with the fluorescent sheet to generate fluorescence emitted in all directions. The detector with time response collects and records the fluorescence. The imaging filter is arranged in the transmission direction of the fluorescent sheet. The imaging recording surface is arranged on the rear side of the imaging filter. The bremsstrahlung radiation part passes through the fluorescent sheet and continues to propagate forward through the imaging filter to reach the imaging recording surface. The imaging recording surface records the spatial distribution of the bremsstrahlung radiation after transmission.

10. A time-space resolved high temperature and high energy superhot electron diagnostic method according to claim 9, characterized in that: The bremsstrahlung radiation is X-rays.

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