CN114047540A - Method and system for measuring beam density distribution of high-current pulse electron beam - Google Patents
Method and system for measuring beam density distribution of high-current pulse electron beam Download PDFInfo
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Abstract
The invention provides a method and a system for measuring the beam density distribution of a high-current pulse electron beam, which solve the problem that the conventional beam measuring method cannot realize the beam density measurement of a complete section of the high-current pulse electron beam. The method comprises the following steps: step one, manufacturing a Cerenkov radiation conversion target; step two, building a measuring system; step three, collecting a light spot image; fourthly, obtaining the relative intensity distribution of the Cerenkov radiation through the gray value distribution of the light spot image; and step five, obtaining beam density distribution. The method of the invention provides a design process of Cerenkov radiation target rotation, thereby providing a basis for realizing beam density distribution measurement. Meanwhile, the method provides a processing method of the beam spot image, and the gray value distribution of the beam spot image is converted into beam density distribution by the method, so that the beam density distribution on the complete section of the high-current pulse electron beam is measured.
Description
Technical Field
The invention belongs to the technical field of pulse power, and particularly relates to a method and a system for measuring the beam density distribution of a high-current pulse electron beam.
Background
In the pulse power device, a diode is used for generating a high-current pulse electron beam, and the electron beam bombards an anode target of the diode to generate X rays. Parameters such as beam intensity, beam density, spatial distribution and the like of the high-current pulse electron beam are directly related to the intensity distribution of the X-ray radiation field. The energy of the high-current pulse electron beam can reach millions of eV, the beam intensity can reach hundreds of thousands of A, the beam measuring equipment is extremely easy to be damaged or failed by electron bombardment due to high electron energy and high electron beam intensity, and the X-ray penetration capability in the measuring environment is extremely strong, so that the high requirements on the shielding and anti-electromagnetic interference capability of the measuring system are provided.
Chinese patent CN103315711A discloses a medical endoscopic Cerenkov fluorescence imaging system, which uses an endoscope to collect Cerenkov fluorescence signals emitted by the combination of a detected object and a probe, and obtains Cerenkov fluorescence images in the detected object through optical fiber transmission and photoelectric conversion to realize high-precision diagnosis of medical biopsy. However, this method is limited in the area of diagnosis for a subject in a narrow and curved space.
Chinese patent CN102981180A discloses a water cerenkov light high-energy particle detector, which uses water as a radiation body, collects the cerenkov light generated by a light collection device in the detector, and finally stores and records the cerenkov light after photoelectric conversion and analog-to-digital conversion by a data acquisition device, and is used for detecting the number of particles of high-energy cosmic particles and the energy thereof. However, this method uses water as a radiator, and is not suitable for a high-current pulsed electron beam environment. .
In the strong laser and particle beam journal, volume 15, paper 4, real-time measurement of beam spot of strong current short pulse electron beam, published by chenofu et al, quartz glass is used as a radiator, and a single-amplitude radiation image is shot by a camera for measuring the beam spot of the electron beam of a linear accelerator. However, this method only acquires beam spot information and does not perform beam density diagnosis for a linear accelerator with low beam intensity.
In the examination of the beam uniformity measurement of a micro faraday cage array, volume 27, 5, of the periodical thesis 2015 for intense laser and particle beams, populus et al published beam uniformity measurement of a micro faraday cage array, which uses other methods to diagnose the profile parameters of electron beams, and uses a faraday cage to be mounted on the anode surface of a diode to directly obtain the beam density intensity of a part of the anode surface, however, the method is limited by the size of a detector, the number of faraday cages is limited, and the beam density distribution information of intense current pulses cannot be completely obtained.
Chinese patent CN102538670A discloses an optical measurement device and method for the size of a micron-sized electron beam focal spot, which causes an electron beam to bombard a semiconductor panel, the semiconductor panel emits a light beam by spontaneous radiation, and the light intensity information of the light beam is measured by an optical measurement method, thereby obtaining the beam spot of the electron beam. However, the semiconductor used in the method can not bear the bombardment of the high-current pulse electron beam, and is only suitable for the electron beam with the size reaching the micron level on the equipment such as an electron microscope, a CRT and the like.
The above documents or patents describe measurement methods that take different technical means to achieve the diagnosis of electron beam current parameters. However, these technical means are not suitable for the high current pulse electron beam, or only can obtain the beam spot, or only can realize the beam density measurement of the local position, and are difficult to apply to the beam density measurement of the complete profile of the high current pulse electron beam.
In the prior art, the diagnosis of electron beam distribution images can be realized by utilizing visible light wave band Cerenkov radiation generated by electrons in a thin transparent medium and by means of visible light high-speed imaging. The method can be used for measuring the density distribution of the high-current electron beam and is not easily influenced by X rays and electromagnetic interference. However, the high-current pulse electron beam has poor collimation, large incident angle distribution and large difference of Cerenkov photon yield, and the good linear relation between Cerenkov radiation intensity and beam density is difficult to ensure; in addition, in the experiment, the luminescence of the diode cathode plasma is overlapped with the Cerenkov radiation spectrum, so that the imaging quality is seriously influenced.
In summary, the current measurement system and experimental method based on cerenkov radiation are difficult to satisfy the beam density distribution measurement of the high current pulse electron beam.
Disclosure of Invention
The invention aims to solve the problem that the existing beam current measuring method cannot realize beam current density measurement of a complete profile of a high-current pulse electron beam, and provides a measuring method and a measuring system for beam current density distribution of the high-current pulse electron beam.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for measuring the beam density distribution of a high-current pulse electron beam comprises the following steps:
step one, manufacturing a Cerenkov radiation conversion target;
1.1) obtaining electron beam energy of diode high current pulse according to diode pulse voltage, and obtaining electron beam incident angle distribution according to diode PIC simulation result;
1.2) establishing a Monte Carlo model, obtaining the transmittance of electrons with different energies in graphite coatings with different thicknesses, and simultaneously obtaining a Cerenkov photon number change curve family of Cerenkov radiation photons generated by the electrons in the fused quartz glass under different diode voltages, different electron incidence angles and different thicknesses of the fused quartz glass;
1.3) determining the thickness of the fused quartz glass according to the electron beam energy and the electron beam incidence angle distribution obtained in the step 1.1) and by combining the Cerenkov photon number change curve family obtained in the step 1.2), so that the Cerenkov photon number change is within 10% under the electron beam incidence angle distribution;
1.4) determining the thickness of the graphite coating in the transmittance of the electrons obtained in the step 1.2) in the graphite coatings with different thicknesses so that the electron transmittance and the plasma-shielding luminous effect of the graphite coating meet the set requirements;
1.5) adding a graphite coating on the surface of the fused quartz glass according to the thickness of the fused quartz glass and the thickness of the graphite coating in the step 1.3) and the step 1.4), and making the rear surface of the fused quartz glass into a frosted surface to finish the Cherenkov radiation conversion target;
step two, building a measuring system;
placing a Rogowski coil and a Cerenkov radiation conversion target along the incident direction of an electron beam, fixing the Cerenkov radiation conversion target on a rotating table, forming an included angle of 45 degrees with the incident direction of the electron beam, and arranging a high-speed imaging unit on one side of the frosting surface of the Cerenkov radiation conversion target;
step three, collecting a light spot image;
acquiring a light spot image on the rear surface of the Cerenkov radiation conversion target by using a high-speed imaging unit, wherein the light spot image comprises the spatial distribution, the gray value and the time information of a light spot;
fourthly, obtaining the relative intensity distribution of Cerenkov radiation through the gray value distribution of the light spot image, and obtaining the relative intensity distribution of beam density at different positions of a beam profile;
step five, obtaining beam density distribution;
obtaining beam intensity at the imaging moment according to a beam intensity curve measured by a Rogowski coil and time information of a light spot image, and carrying out weighted average on the beam intensity to obtain beam density distribution on a beam profile;
5.1) calculating according to the structural parameters of the Cerenkov radiation conversion target to obtain the spatial resolution D of the Cerenkov radiation conversion target;
5.2) calculating to obtain the number D of pixels corresponding to the imaging system with the spatial resolution D (D/(f multiplied by p) according to the reduction multiple f of the high-speed imaging unit and the size p of a single pixel of the high-speed imaging unit;
5.3) dividing the light spot image into i areas averagely, wherein the size of a single area is d multiplied by d pixel points, and calculating the gray value sum N (i) in the single area;
5.4) measuring the beam intensity I of the electron beam according to the Rogowski coil0Obtaining the beam current density in each DxD region
Wherein J (i) is the beam current density in each D × D region.
Further, in the step 1.5), according to the structural parameters obtained in the step 1.3) and the step 1.4), a graphite coating is added on the surface of the fused silica glass in an electrophoresis mode.
Further, in the second step, the Cerenkov radiation conversion target is arranged on the rotating table and forms an included angle of 45 degrees with the incident direction of the electron beam.
Further, in the first step, the thickness of the graphite coating is 10-50 μm, and the thickness of the fused quartz glass is 0.2-1 mm.
Meanwhile, the invention also provides a system for measuring the beam density distribution of the high-current pulse electron beam, which comprises a Rogowski coil, a Cerenkov radiation conversion target, a rotating table, a high-speed imaging unit and a data processing unit; the Rogowski coil and the Cerenkov radiation conversion target are positioned in the vacuum cavity; the Rogowski coil is used for obtaining the beam intensity of an electron beam and comprises a coil and a shielding box, wherein the shielding box is of an annular structure, and the coil is covered in an annular cavity; the Cerenkov radiation conversion target comprises a graphite coating and fused quartz glass, the graphite coating is arranged on the front surface of the fused quartz glass and faces to an electron beam incidence end, and the rear surface of the fused quartz glass is a frosted surface; the rotating platform is arranged below the Cerenkov radiation conversion target and is used for adjusting an included angle between the Cerenkov radiation conversion target and the incident direction of the electron beam; the high-speed imaging unit is arranged on one side of the Cerenkov radiation conversion target and is used for acquiring Cerenkov radiation distribution information and acquiring a light spot image; and the data processing unit is connected with the high-speed imaging unit and is used for processing the light spot image acquired by the high-speed imaging unit and the beam intensity of the electron beam acquired by the Rogowski coil to obtain beam density distribution on a beam profile.
Furthermore, the high-speed imaging unit comprises a high-speed imaging camera, an optical filter and a reflector which are arranged in the electromagnetic shielding box, and the high-speed imaging camera images the light spots on the rear surface of the conversion target through the optical filter and the reflector.
Further, the high-speed imaging camera is an ICCD camera or a framing camera.
Furthermore, the high-speed imaging camera and the pulse power source are both connected with the trigger, and the trigger delay of the pulse power source and the high-speed imaging camera is adjusted through the trigger to obtain the beam profile density distribution of the diode at different moments.
Furthermore, the rotating platform is an electric rotating platform or a manual rotating platform, and the adjustment of the included angle between the Cerenkov radiation conversion target and the incident direction of the electron beam is realized.
Compared with the prior art, the invention has the following beneficial effects:
1. the method of the invention provides a design process of the Cerenkov radiation conversion target, and the conversion target can shield plasma luminous interference and ensure the linear relation between Cerenkov radiation intensity and beam intensity, thereby providing a basis for realizing beam density distribution measurement. Meanwhile, the method provides a processing method of the beam spot image, and the gray value distribution of the beam spot image is converted into beam density distribution by the method, so that the beam density distribution on the complete section of the high-current pulse electron beam is measured.
2. The measuring system can completely acquire the beam density distribution on the electron beam profile, and has simple structure and strong electromagnetic interference resistance. Meanwhile, the system uses a Cerenkov radiation conversion target structure plated with graphite fused quartz glass, so that the problem of cathode plasma luminescence interference is solved.
3. The invention provides a method for selecting proper Cerenkov radiation conversion target structure parameters by utilizing numerical simulation, so that the linear relation between Cerenkov radiation intensity and beam intensity can be ensured.
Drawings
FIG. 1 is a schematic diagram of a system for measuring a beam density distribution of a high current pulsed electron beam according to an embodiment of the present invention;
fig. 2 is a schematic view of the installation of the cerenkov radiation conversion target in the embodiment of the present invention.
Reference numerals: the device comprises a pulse power source 1, a diode cathode 2, a vacuum cavity 3, an electron beam 4, a diode anode 5, a Rogowski coil 6, an optical window 7, a Cherenkov radiation conversion target 8, an electron absorption layer 9, a reflector 10, an optical filter 11, a high-speed imaging camera 12, an electromagnetic shielding box 13, a trigger 14, a rotating platform 15, an observation window 16 and a base 17.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention and are not intended to limit the scope of the present invention.
The invention provides a method and a system for measuring the beam density distribution of a high-current pulse electron beam based on Cerenkov radiation and high-speed optical imaging, and can obtain complete beam density distribution information on a beam profile.
The measuring system of the high current pulse electron beam current density distribution comprises a Rogowski coil 6, a Cerenkov radiation conversion target 8, a rotating platform 15, a high-speed imaging unit and a data processing unit; the rogowski coil 6, the cerenkov radiation conversion target 8 are located within the vacuum chamber 3, and the center of the cerenkov radiation conversion target 8 is located on the centerline of the rogowski coil 6. The Rogowski coil 6 is used for measuring the intensity of the current of the electron beam 4 passing through the Cerenkov radiation conversion target 8, and specifically comprises a coil and a shielding box, wherein the shielding box is of an annular structure, the coil is wrapped inside an annular cavity, and the shielding box is used for shielding the interference of the electron beam 4 and X rays in space. The Cerenkov radiation conversion target 8 main body consists of a graphite coating and fused quartz glass, the graphite coating is arranged on the front surface of the fused quartz glass and faces the incident end of the electron beam 4, and the rear surface of the fused quartz glass is a frosted surface; the structural parameters of the graphite coating and the fused silica glass are determined by the results of the Monte Carlo model on the luminous depth and luminous intensity of the electron beam 4 in the transparent medium, and the structural parameters are the material thickness. Specifically, the graphite coating has a thickness of 10 to 50 μm, which ensures shielding of plasma emission from the cathode 2 of the diode from the electron incident direction. The thickness of the fused silica glass is 0.2 to 1 mm. The fused quartz glass has high visible light transmittance and strong electron beam 4 bombardment resistance, and the thickness of the fused quartz glass is reduced as much as possible to improve the spatial resolution on the premise of ensuring the detectable Cerenkov radiation intensity. The rear surface of the fused quartz glass is set as a frosted surface, and the Cerenkov radiation generated by the electron beam 4 is converted into light spots through the frosted surface.
The rotary stage 15 can be electrically or manually operated to adjust the angle between the Cerenkov radiation conversion target 8 and the incident direction of the electron beam 4. The high-speed imaging unit is arranged on one side of the Cerenkov radiation conversion target 8 and used for acquiring Cerenkov radiation distribution information and acquiring a light spot image. The high-speed imaging unit can specifically comprise an ICCD camera or a framing camera and is used for accurately acquiring Cerenkov radiation distribution information of the rear surface of the fused quartz glass. The data processing unit is connected with the high-speed imaging unit and is used for processing the light spot image acquired by the high-speed imaging unit and the beam intensity of the electron beam 4 acquired by the Rogowski coil 6 to obtain beam density distribution on a beam profile.
The invention also provides a method for measuring the beam density distribution of the high-current pulse electron beam, which comprises the following steps:
step one, manufacturing a Cerenkov radiation conversion target 8;
1.1) acquiring the energy of a diode high current pulse electron beam according to the diode pulse voltage, and acquiring the incident angle distribution of the electron beam according to the diode PIC simulation result;
1.2) establishing a Monte Carlo model, obtaining the transmittance of electrons with different energies in graphite coatings with different thicknesses, and simultaneously obtaining a Cerenkov photon number change curve family of Cerenkov radiation photons generated by the electrons in the fused quartz glass under different diode voltages, different electron incidence angles and different thicknesses of the fused quartz glass;
1.3) determining the thickness of the fused quartz glass according to the electron beam energy and the electron beam incidence angle distribution provided in the step 1.1) and by combining the Cerenkov photon number change curve family obtained in the step 1.2), and ensuring that the Cerenkov photon number change is within 10% under certain electron beam incidence angle distribution;
1.4) determining the thickness of the graphite coating according to the transmittance of the electrons with different energies obtained in the step 1.2) in the graphite coating with different thicknesses and under the condition of ensuring higher transmittance of the electrons and the plasma-shielding luminous effect of the graphite coating;
1.5) according to the thickness of the fused quartz glass and the thickness of the graphite coating in the step 1.3) and the step 1.4), adding the graphite coating on the surface of the fused quartz glass in an electrophoresis mode, and making the rear surface of the fused quartz glass into a frosted surface to finish the Cherenkov radiation conversion target 8;
step two, building a measuring system;
a Rogowski coil 6 and a Cerenkov radiation conversion target 8 are arranged along the incident direction of the electron beam 4, the Cerenkov radiation conversion target 8 is fixed on a rotating table 15, and the included angle between the Cerenkov radiation conversion target and the incident direction of the electron beam 4 is 45 degrees; arranging a high-speed imaging unit at one side of the frosted surface of the Cerenkov radiation conversion target 8;
step three, collecting a light spot image;
acquiring a light spot image on the rear surface of the Cerenkov radiation conversion target 8 by using a high-speed imaging unit, wherein the light spot image comprises the spatial distribution, the gray value and the time information of a light spot;
fourthly, obtaining the relative intensity distribution of Cerenkov radiation through the gray value distribution of the light spot image, and obtaining the relative intensity distribution of beam density at different positions of a beam profile;
step five, obtaining beam density distribution;
obtaining beam intensity at the imaging moment according to a beam intensity curve measured by the Rogowski coil 6 and time information of a light spot image, and carrying out weighted average on the beam intensity to obtain beam density distribution on a beam profile;
5.1) calculating according to the structural parameters of the Cerenkov radiation conversion target 8 to obtain the spatial resolution D of the Cerenkov radiation conversion target 8;
5.2) calculating to obtain the number D of pixels corresponding to the imaging system with the spatial resolution D (D/(f multiplied by p) according to the reduction multiple f of the high-speed imaging unit and the size p of a single pixel of the high-speed imaging unit;
5.3) dividing the light spot image into i areas averagely, wherein the size of a single area is d multiplied by d pixel points, and calculating the gray value sum N (i) in the single area;
5.4) measuring the beam intensity I of the electron beam 4 according to the Rogowski coil 60Obtaining the beam current density in each DxD region
Wherein J (i) is the beam current density in each D × D region.
The method provides a design method of the Cerenkov radiation target, and the conversion target can shield plasma luminous interference and ensure the linear relation between the Cerenkov radiation intensity and the beam intensity, thereby providing a basis for realizing beam density distribution measurement. Meanwhile, the method provides a processing method of the beam spot image, and the gray value distribution of the beam spot image is converted into beam density distribution by the method, so that the beam density distribution on the complete section of the high-current pulse electron beam is measured.
As shown in fig. 1 and 2, the beam density distribution measuring system of the present invention takes a self-magnetic pinch diode as an example, a vacuum chamber 3 is installed at the end of the diode, and is closely attached to an anode 5 of the diode, and an electron absorption layer 9 is installed at the end of the vacuum chamber 3. A rogowski coil 6 is mounted on the inner wall of the vacuum chamber 3. The electron beam 4 is generated from the diode, passes through the diode anode 5 into the vacuum chamber 3, passes through the rogowski coil 6 and impinges at an angle of incidence on the cerenkov radiation conversion target 8. Cerenkov radiation is generated when the electron velocity is greater than the speed of light in the cerenkov radiation conversion target 8. The radiation photons enter the high-speed imaging unit after being scattered by the surface of the Cerenkov radiation conversion target 8. The imaging system is placed in an electromagnetic shielding box 13, and a high-speed imaging camera 12 images light spots on the back surface of the Cerenkov radiation conversion target 8 through an optical filter 11 and a reflector 10. When the device is used, trigger delay of the pulse power source 1 and the high-speed imaging camera 12 is adjusted through the trigger 14, and beam profile density distribution of the diode at different moments can be obtained.
Before the experiment is started, the structural parameters of the conversion target are determined according to the design method of the Cerenkov radiation conversion target 8. The graphite coating with the thickness of several micrometers on the surface of the conversion target can effectively shield the light-emitting interference of the plasma of the diode cathode 2, simultaneously ensures the high penetration rate of the electron beam 4, has high graphite melting point, is not easy to vaporize and fall off by electron bombardment, and can realize the reuse of the Cerenkov radiation conversion target 8. According to the working parameters (pulse voltage and electron incidence angle distribution) of the diode, a Monte Carlo model is established to estimate the Cerenkov radiation photon yield in the fused quartz glass under different working parameters of the diode. On the premise of ensuring that the photon yield and the beam intensity have a better linear relation, the thickness of the fused quartz glass is reduced as much as possible so as to improve the spatial resolution. And comprehensively considering the requirements of spatial resolution, photon yield and the like to determine the thickness of the fused quartz glass.
In the experiment, as shown in fig. 2, the cerenkov radiation conversion target 8 and the precision rotary table 15 are fixed on the base 17 together, and the included angle between the conversion target and the electron beam 4 is adjusted by rotating the precision rotary table 15. The observation window 16 is used for observing the state of the conversion target before and after the experiment, and the optical window 7 is used for imaging the rear surface of the conversion target by the high-speed imaging unit. After the high-speed imaging unit obtains the light spot image, the space distribution, the intensity distribution and the time information of the light spot are obtained through image processing, and finally the beam density distribution condition on the beam profile is obtained.
Claims (10)
1. A method for measuring the beam density distribution of a high-current pulse electron beam is characterized by comprising the following steps:
step one, manufacturing a Cerenkov radiation conversion target;
1.1) obtaining electron beam energy of diode high current pulse according to diode pulse voltage, and obtaining electron beam incident angle distribution according to diode PIC simulation result;
1.2) establishing a Monte Carlo model, obtaining the transmittance of electrons with different energies in graphite coatings with different thicknesses, and simultaneously obtaining a Cerenkov photon number change curve family of Cerenkov radiation photons generated by the electrons in the fused quartz glass under different diode voltages, different electron incidence angles and different thicknesses of the fused quartz glass;
1.3) determining the thickness of the fused quartz glass according to the electron beam energy and the electron beam incidence angle distribution obtained in the step 1.1) and by combining the Cerenkov photon number change curve family obtained in the step 1.2), so that the Cerenkov photon number change is within 10% under the electron beam incidence angle distribution;
1.4) determining the thickness of the graphite coating in the transmittance of the electrons obtained in the step 1.2) in the graphite coatings with different thicknesses so that the electron transmittance and the plasma-shielding luminous effect of the graphite coating meet the set requirements;
1.5) adding a graphite coating on the surface of the fused quartz glass according to the thickness of the fused quartz glass and the thickness of the graphite coating in the step 1.3) and the step 1.4), and making the rear surface of the fused quartz glass into a frosted surface to finish the Cherenkov radiation conversion target;
step two, building a measuring system;
placing a Rogowski coil and a Cerenkov radiation conversion target along the incident direction of an electron beam, fixing the Cerenkov radiation conversion target on a rotating table, forming an included angle of 45 degrees with the incident direction of the electron beam, and arranging a high-speed imaging unit on one side of the frosting surface of the Cerenkov radiation conversion target;
step three, collecting a light spot image;
acquiring a light spot image on the rear surface of the Cerenkov radiation conversion target by using a high-speed imaging unit, wherein the light spot image comprises the spatial distribution, the gray value and the time information of a light spot;
fourthly, obtaining the relative intensity distribution of Cerenkov radiation through the gray value distribution of the light spot image, and obtaining the relative intensity distribution of beam density at different positions of a beam profile;
step five, obtaining beam density distribution;
obtaining beam intensity at the imaging moment according to a beam intensity curve measured by a Rogowski coil and time information of a light spot image, and carrying out weighted average on the beam intensity to obtain beam density distribution on a beam profile;
5.1) calculating according to the structural parameters of the Cerenkov radiation conversion target to obtain the spatial resolution D of the Cerenkov radiation conversion target;
5.2) calculating to obtain the number D of pixels corresponding to the imaging system with the spatial resolution D (D/(f multiplied by p) according to the reduction multiple f of the high-speed imaging unit and the size p of a single pixel of the high-speed imaging unit;
5.3) dividing the light spot image into i areas averagely, wherein the size of a single area is d multiplied by d pixel points, and calculating the gray value sum N (i) in the single area;
5.4) root of Szechwan lovageMeasuring the beam intensity I of the electron beam according to the Rogowski coil0Obtaining the beam current density in each DxD region
Wherein J (i) is the beam current density in each D × D region.
2. The method for measuring the beam density distribution of a high-current pulsed electron beam according to claim 1, wherein: in the step 1.5), according to the structural parameters obtained in the step 1.3) and the step 1.4), a graphite coating is added on the surface of the fused quartz glass in an electrophoresis mode.
3. The method for measuring the beam density distribution of a high-current pulsed electron beam according to claim 1, wherein: and in the second step, the Cerenkov radiation conversion target is arranged on the rotating table and forms an included angle of 45 degrees with the incident direction of the electron beam.
4. The method for measuring the beam density distribution of a high-current pulsed electron beam according to claim 1, wherein: in the first step, the thickness of the graphite coating is 10-50 μm, and the thickness of the fused quartz glass is 0.2-1 mm.
5. A measurement system for the beam density distribution of a high-current pulse electron beam is characterized in that: the device comprises a Rogowski coil (6), a Cerenkov radiation conversion target (8), a rotating platform (15), a high-speed imaging unit and a data processing unit;
the Rogowski coil (6) and the Cerenkov radiation conversion target (8) are positioned in the vacuum cavity (3);
the Rogowski coil (6) is used for obtaining the beam intensity of the electron beam (4), and comprises a coil and a shielding box, wherein the shielding box is of an annular structure and covers the coil in an annular cavity;
the Cerenkov radiation conversion target (8) comprises a graphite coating and fused quartz glass, the graphite coating is arranged on the front surface of the fused quartz glass and faces the incident end of the electron beam (4), and the rear surface of the fused quartz glass is a frosted surface;
the rotating table (15) is arranged below the Cerenkov radiation conversion target (8) and is used for adjusting an included angle between the Cerenkov radiation conversion target (8) and the incident direction of the electron beam (4);
the high-speed imaging unit is arranged on one side of the Cerenkov radiation conversion target (8) and is used for acquiring Cerenkov radiation distribution information to obtain a light spot image;
and the data processing unit is connected with the high-speed imaging unit and is used for processing the light spot image acquired by the high-speed imaging unit and the beam intensity of the electron beam acquired by the Rogowski coil (6) to obtain beam density distribution on a beam profile.
6. The system for measuring beam current density distribution of a high current pulsed electron beam according to claim 5, wherein: the high-speed imaging unit comprises a high-speed imaging camera (12), an optical filter (11) and a reflector (10) which are arranged in an electromagnetic shielding box (13), and the high-speed imaging camera (12) images light spots on the rear surface of the Cerenkov radiation conversion target (8) through the optical filter (11) and the reflector (10).
7. The system for measuring beam density distribution of a high current pulsed electron beam according to claim 6, wherein: the high-speed imaging camera (12) and the pulse power source (1) are connected with the trigger (14), and trigger time delay of the pulse power source (1) and the high-speed imaging camera (12) is adjusted through the trigger (14) to obtain beam profile density distribution of the diode at different moments.
8. The system for measuring beam density distribution of a high current pulsed electron beam according to claim 7, wherein: the high-speed imaging camera (12) is an ICCD camera or a framing camera.
9. The system for measuring beam current density distribution of a high current pulsed electron beam according to claim 5, wherein: the thickness of the graphite coating is 10-50 mu m, and the thickness of the fused quartz glass is 0.2-1 mm.
10. The system for measuring beam current density distribution of a high current pulsed electron beam according to claim 5, wherein: the rotating platform (15) is an electric rotating platform or a manual rotating platform.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63241375A (en) * | 1987-03-27 | 1988-10-06 | Kenichi Ueda | Current measurement of electron beam |
| CN106950590A (en) * | 2017-05-08 | 2017-07-14 | 中国工程物理研究院流体物理研究所 | A kind of micron dimension conversion target assembly measured for electron beam emittance |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63241375A (en) * | 1987-03-27 | 1988-10-06 | Kenichi Ueda | Current measurement of electron beam |
| CN106950590A (en) * | 2017-05-08 | 2017-07-14 | 中国工程物理研究院流体物理研究所 | A kind of micron dimension conversion target assembly measured for electron beam emittance |
Non-Patent Citations (1)
| Title |
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| YANA ZLATEVA等: "Cherenkov emission-based external radiotherapy dosimetry: I. Formalism and feasibility" * |
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