CN109922591B - Medium-energy large-beam spot weak-current electron acquisition device - Google Patents
Medium-energy large-beam spot weak-current electron acquisition device Download PDFInfo
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Abstract
The invention provides an acquisition device for medium-energy large-beam spot weak-current electrons, which relates to the technical field of electron accelerator beam control and is used for generating electron flow; an acceleration tube connected to the electron gun for accelerating the electron flow to obtain a beam having a certain energy; the beam line is arranged at the outlet of the accelerating tube and used for focusing and then releasing the beam current according to the beam expanding spiral tube arranged on the beam line so as to realize the beam expansion of the beam current; the first beam limiting diaphragm hole and the second beam limiting diaphragm hole are arranged at the outlet of the beam expanding solenoid and are used for intercepting the beam at the edge position to obtain the target beam at the central area; the beam measuring module is arranged on the beam and is used for detecting the beam intensity, uniformity and total beam flow of the beam. The electron energy generated by the invention is continuously adjustable from 10-300 kiloelectron volts, and the beam intensity is continuously adjustable from a few milliamperes to a few picoamperes; the generated beam is direct current, the diameter of the beam spot can reach hundreds of millimeters, and the cross section of the beam is uniformly distributed and has high stability.
Description
Technical Field
The invention relates to the technical field of beam control of electron accelerators, in particular to an acquisition device for medium-energy large-beam spot weak-current electrons.
Background
An electron source, also known as an electron accelerator, is a device that uses an artificial approach to accelerate charged particles to a higher energy. Electrons, protons, deuterons, alpha particles, and other heavy ions of various energies can be generated using this device. By the action of these directly accelerated charged particles with matter, various charged and uncharged secondary particles can also be generated, like gamma particles, neutrons and various mesons, hyperon, counter particles etc. Electron accelerators can be classified into many types according to classification criteria. For example, the low energy accelerator, the medium energy accelerator, the high energy accelerator and the ultra-high energy accelerator can be classified according to the energy of the accelerated particles; the beam intensity is different, and the beam intensity can be divided into a strong flow accelerator, a medium flow accelerator and a weak flow accelerator. The weak current electron source device starts to appear abroad in the late 20 th century, and is mainly used in the fields of biology and medicine, material science and space and aerospace, but for technical confidentiality reasons, the related data about the weak current electron source device are not disclosed. The domestic research in the field starts later, and the related data about the weak current electron source is very little.
The main characteristics of the weak current electron source are that the electron energy is low, the electron current is weak, the electrons with low energy are easy to be disturbed, the electrons deviate from the original transmission path due to the small magnetic field, and the longer the transmission distance is, the more easily the influence of the magnetic field is received. The transverse magnetic field perpendicular to the beam direction generated by the outside is easy to cause interference to the beam, while the longitudinal magnetic field along the beam direction does not cause interference to the beam. The deflection angle of the electron deflection caused by the disturbing magnetic field is calculated as follows:
tanθ＝BL/(Bρ)
Wherein B is the average residual transverse magnetic field; l is the length of a transport line of the beam; and Bρ is the magnetic stiffness of the electrons.
In order to weaken the beam intensity, it is necessary to lengthen the length of the transport line of the beam, and as can be seen from the above formula, an increase in the length of the transport line causes an increase in the deflection angle θ of the electron deflection, so that the lower energy limit of the output beam is high. Therefore, the output beam has a larger energy range, and the output beam has higher beam intensity at the same time; ensuring that the output beam has weaker beam intensity, and the output beam has a smaller energy range at the same time; this contradiction makes a medium-energy weak-current power source a technical problem.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides an acquisition device for medium-energy large-beam spot weak current electrons, which specifically comprises the following steps:
An electron gun for generating an electron stream;
an acceleration tube connected to the electron gun for accelerating the electron flow to obtain a beam having a certain energy;
The beam line is arranged at the outlet of the accelerating tube and is used for processing the beam current according to a processing device arranged on the beam line so as to obtain a target beam current;
The processing device comprises:
The beam expanding solenoid is used for releasing the focused beam to realize the beam expanding of the beam;
the first beam limiting diaphragm is arranged at the outlet of the beam expanding solenoid and is used for intercepting the beam at the edge position to obtain a target beam at the central area, and the aperture of the first beam limiting diaphragm is consistent with the beam spot diameter of the target beam;
The second beam limiting diaphragm is arranged at the outlet of the first beam limiting diaphragm and is used for forming a vertical path with the first beam limiting diaphragm to acquire the target beam which is emitted vertically, and the aperture of the second beam limiting diaphragm is consistent with the beam spot diameter of the target beam;
The beam measuring module is arranged on the beam line and is used for detecting the beam intensity, the uniformity and the total beam flow of the beam;
The high-pressure steel barrel is arranged outside the electron gun and the accelerating tube and is used for providing a stable use environment for the electron gun and the accelerating tube.
Preferably, the periphery of the wire harness is wrapped with a shielding cylinder for shielding external magnetic field interference.
Preferably, the acquisition device is installed according to a geomagnetic field direction of an installation site to reduce interference of an external transverse magnetic field perpendicular to the beam direction.
Preferably, the electron gun uses a pure tungsten wire as a cathode of the electron gun.
Preferably, the accelerating tube is an isocratic accelerating tube.
Preferably, the beam measuring module includes:
the flange first cylinder is arranged between the accelerating tube and the beam expanding solenoid and is used for measuring the beam intensity of the beam before beam expansion;
The terminal uniformity instrument is arranged between the first beam limiting diaphragm and the second beam limiting diaphragm and is used for measuring the uniformity and the total beam flow of the target beam.
Preferably, the adjustment mode of the beam intensity of the target beam comprises adjusting the temperature of a cathode of the electron gun, and/or adjusting the voltage of a grid electrode of the electron gun, and/or adjusting the focusing magnetic field of the beam expanding solenoid.
Preferably, the technical parameters of the beam expansion solenoid are calculated according to a certain rule according to the parameters of the target beam.
Preferably, the high-pressure steel barrel further comprises:
The voltage doubling rectifying column is arranged on the bottom flange of the high-voltage steel barrel and used for providing a negative high-voltage power supply for the cathode of the electron gun;
The negative high-voltage platform is arranged above the voltage doubling rectifying column and is used for installing power supply equipment for supplying power to a cathode, a grid and an anode of the electron gun;
and the isolation transformer is arranged on the top flange of the high-voltage steel drum and is used for supplying power to the power supply equipment.
The technical scheme has the following advantages or beneficial effects:
1) The energy of the generated electrons is continuously adjustable from 10-300 kilo electron volts, and the beam intensity is continuously adjustable from a few milliamperes to a few picoamperes;
2) The generated beam is direct current, the diameter of a beam spot can reach hundreds of millimeters, the unevenness and the instability of the cross section distribution of the beam are less than +/-5 percent, and the energy instability is less than five parts per million;
3) Has unique application in the fields of biology and medicine, material science and space environment simulation.
Drawings
FIG. 1 is a schematic diagram of a device for obtaining electrons with medium energy and large beam spots and weak current in a preferred embodiment of the invention;
FIG. 2 is a schematic diagram of an equivalent circuit of an apparatus for obtaining electrons with medium energy and large beam spot and weak current in a preferred embodiment of the present invention;
FIG. 3 is a schematic diagram of a control apparatus for a beam line vacuum environment in accordance with a preferred embodiment of the present invention;
FIG. 4 is a schematic diagram of a control module according to a preferred embodiment of the present invention;
Fig. 5 is a schematic diagram of the principle of beam expansion in a preferred embodiment of the present invention.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples. The present invention is not limited to the embodiment, and other embodiments may fall within the scope of the present invention as long as they conform to the gist of the present invention.
In a preferred embodiment of the present invention, based on the above-mentioned problems existing in the prior art, an apparatus for obtaining electrons with medium and large beam spots and weak current is provided, as shown in fig. 1 and 2, which specifically includes:
an electron gun 200 for generating an electron flow;
an acceleration tube 300 connected to the electron gun 200 for accelerating the electron flow to obtain a beam having a certain energy;
A beam line 400 disposed at an outlet of the acceleration tube 300, for processing the beam according to a processing device disposed on the beam line 400 to obtain a target beam;
the processing device comprises:
a beam expansion solenoid 401 for releasing the focused beam to expand the beam;
A first beam limiting diaphragm 402, disposed at an outlet of the beam expanding solenoid 401, for intercepting the beam at the edge position to obtain a target beam at the central area, where an aperture of the first beam limiting diaphragm 402 is consistent with a beam spot diameter of the target beam;
The second beam limiting diaphragm 403 is disposed at the outlet of the first beam limiting diaphragm 402, and is configured to form a vertical path with the first beam limiting diaphragm 402 to obtain the target beam emitted vertically, where the aperture of the second beam limiting diaphragm 403 is consistent with the beam spot diameter of the target beam;
The beam measuring module is arranged on the beam line 400 and is used for detecting the beam intensity, uniformity and total beam flow of the beam;
The high-pressure steel tub 100 is disposed outside the electron gun 200 and the acceleration tube 300, and is used for providing a stable use environment for the electron gun 200 and the acceleration tube 300.
Specifically, in this embodiment, after the electron beam is accelerated by the accelerating tube 300, a beam is obtained, after the beam is focused by the beam expansion solenoid 401, the beam is dispersed again by a focal point, and after drifting for a certain distance, the beam spot naturally increases, at this time, a first beam limiting diaphragm 402 and a second beam limiting diaphragm 403 with the same diameter as the target beam spot are placed, a beam with relatively uniform distribution in the central area of the beam is selected to pass through, and the beams with the rest edges are blocked, so that the purposes of obtaining the beam with uniform distribution, weak beam intensity and meeting the diameter of the target beam spot are achieved.
In this embodiment, the electron gun 200 and the acceleration tube 300 are placed in a closed high-pressure steel tub 100, and the high-pressure steel tub 100 is filled with SF6 insulating gas of 3 atm. The insulating gas is a good insulating medium, so that the pressure resistance is improved; and the closed high-voltage steel drum 100 provides a relatively stable working environment for the electron gun 200, which is not only a high-voltage shielding case, but also is beneficial to the stable operation of electron flow.
In this embodiment, the electron gun 200 is mounted on the head of the acceleration tube 300, both of which are vacuum environments inside and 3atm of SF6 insulating gas outside.
In a preferred embodiment of the present invention, the wire harness 400 is peripherally wrapped with a shielding cylinder 404 for shielding external magnetic field interference.
In particular, in this embodiment, since the present invention adopts a beam expanding method to obtain a large beam spot, the beam current is characterized by direct current and is continuous in time, which is essentially different from the method of obtaining a large beam spot by a scanning method, and the large beam spot obtained by the scanning method is discontinuous in time. Meanwhile, the invention adopts a beam expanding mode to obtain a large beam spot, so that the beam can drift for a longer distance after the beam is expanded, and the beam spot can be expanded to a large enough size, so that the aim of obtaining a weak beam through beam limiting can be fulfilled. However, the magnetic rigidity of the medium-energy electrons is very small, and the medium-energy electrons are extremely easy to be influenced by surrounding stray magnetic fields to deviate from the original transmission path, and the longer the transmission distance is, the more easily the influence of the magnetic field is received. Therefore, in order to prevent the influence of the stray magnetic field, a high permeability shielding cylinder 404 shielding the interference of the stray magnetic field is wrapped around the wire harness 400. Further, the components on the wire harness 400 are made of non-magnetic materials, and the appropriate wire harness length is selected.
In this embodiment, as shown in fig. 3, a vacuum chamber 405 is further disposed on the beam line 400, for providing a vacuum environment for the electron beam current; the beam line 400 is further provided with a vacuum gauge 406 for monitoring the vacuum pressure in the vacuum chamber 405; the harness 400 is also provided with a bleed valve 407 for leak detection and inflation of the vacuum chamber 405; the harness 400 is further provided with a plate valve 408 for protecting a molecular pump 409 provided on the harness 400; the wire harness 400 is further provided with a solenoid valve 410 for performing pipeline switching on a backing pump 411 provided on the wire harness 400; also provided on harness 400 is an oil separator 412 for removing residual oil vapor from vacuum chamber 405 and for cleaning vacuum chamber 405.
In a preferred embodiment of the invention, the acquisition device is installed according to the geomagnetic field direction of the installation site so as to reduce the interference of external transverse magnetic fields perpendicular to the beam direction.
Specifically, in the present embodiment, since the transport direction of beam electrons in the acceleration tube 300 is extremely susceptible to interference of external stray magnetic fields, the above-described installation according to the geomagnetic field direction of the installation site is adopted. For the components which are easy to generate the interference magnetic field, the components are arranged at a position far from the axis of the beam without affecting the functionality of the components, so that the interference of the interference magnetic field is further reduced.
In the preferred embodiment of the present invention, the electron gun 200 employs a pure tungsten wire as the cathode of the electron gun 200.
Specifically, in the present embodiment, the electron gun 200 generates a thermal confinement flow because of the weak flow and no accumulation of space charges exists between the cathode and the anode. The pure tungsten wire is adopted as the cathode of the electron gun 200, the energy of emitted electrons can be changed by adjusting the temperature of the tungsten wire and matching with the grid potential, and the beam current can be further regulated and attenuated by utilizing the subsequent beam expanding action.
In a preferred embodiment of the present invention, the acceleration tube 300 is an isocratic acceleration tube.
Specifically, in this embodiment, the isocratic accelerating tube is equipped with a voltage-dividing resistor, a uniform ring, a discharge ball gap, and the like, which not only has a voltage-equalizing effect, but also can effectively improve the overall withstand voltage of the accelerating tube 300, and does not perform a larger focusing and angle-scattering effect on the beam during the acceleration process of the beam, thereby providing a powerful condition for the use of the processing device on the subsequent beam line 400.
In a preferred embodiment of the present invention, the beam measuring module includes:
a flange first cylinder 501 disposed between the accelerating tube 300 and the beam expansion solenoid 401 for measuring the beam intensity of the beam before the beam expansion;
The terminal homogenizer 502 is disposed between the first beam limiting diaphragm 402 and the second beam limiting diaphragm 403, and is used for measuring the uniformity and total beam flow of the target beam.
Specifically, in this embodiment, the flange first cylinder 501 is connected to a four-channel front-end, where the flange first cylinder 501 collects the beam current before beam expansion, and the four-channel front-end performs the measurement of the beam current intensity; the terminal uniformity meter 502 is connected with two weak current measuring instruments, wherein the terminal uniformity meter 502 collects target beam current, and the two weak current measuring instruments measure uniformity and total beam current. The terminal uniformity meter 502 measures the uniformity of the target beam first and then measures the total beam of the target beam to save the measurement time.
In a preferred embodiment of the present invention, the adjustment of the beam intensity of the target beam includes adjusting the temperature of the cathode of the electron gun 200, and/or adjusting the voltage of the grid of the electron gun 200, and/or adjusting the focusing magnetic field of the beam expanding solenoid 401.
Specifically, in this embodiment, through the cooperation of the above three adjustment manners of beam intensity, the beam intensity of the target beam can be continuously adjustable from several milliamperes to several picoamperes.
In a preferred embodiment of the present invention, the technical parameters of the beam expansion solenoid 401 are calculated according to a certain rule according to the parameters of the target beam.
Specifically, in this embodiment, the calculation according to a certain rule may be calculation according to a gaussian distribution formula. Since the electron beam cross-sectional distribution has the characteristic of gaussian distribution, the technical parameters of the beam expansion solenoid 401 can be calculated according to the gaussian distribution formula.
In the preferred embodiment of the present invention, the high pressure steel tub 100 further includes:
The voltage doubling rectifying column 701 is installed on the bottom flange 101 of the high-voltage steel drum 100 and is used for providing negative high-voltage power for the cathode of the electron gun 200;
a negative high-voltage stage 702 is disposed above the voltage doubling rectifying column 701, and is used for installing power supply equipment for supplying power to the cathode, the grid and the anode of the electron gun 200.
An isolation transformer 703 is mounted on the top flange 102 of the high voltage steel drum 100 for supplying power to the power supply equipment.
Specifically, in the present embodiment, as shown in fig. 2, the electron gun 200 includes a cathode 201, a grid 202, and an anode 203, wherein the cathode 201 is connected to a negative high voltage power supply provided by a voltage doubler rectification column 701 and a cathode power supply 704 provided by a power supply device, respectively; the gate 202 is connected to a gate power supply 705 provided by a power supply device and the anode 203 is connected to an anode power supply 706 provided by the power supply device. The invention adopts the negative high-voltage power supply to accelerate the electron flow to the required energy at one time. The negative high-voltage power supply adopts a voltage doubling rectification mode, and ripple waves and instability reach the level of one ten thousandth, so that the instability of weak-current electrons obtained by the obtaining device can also reach one ten thousandth.
In this embodiment, a manhole flange 103 is disposed on one side of the high-voltage steel drum 100, and after the manhole flange 103 is removed, the high-voltage steel drum 100 can be accessed to perform installation work such as wiring on power equipment on a negative high-voltage platform. The negative high-voltage table 702 is covered with a corona cover outside for improving the withstand voltage of the negative high-voltage table 702.
In this embodiment, as shown in fig. 4, the control module 1 is a PLC controller, where the control module 1 may be divided into two parts, and one part is disposed on the negative high-voltage platform 702 of the high-voltage steel drum 100, for controlling the power supply device and communicating with a control computer 2 through a network switch 3 and an optical fiber 4; the other part is arranged on the ground potential 5 and is used for controlling the devices such as the beam expansion solenoid 401, the beam measuring module 500 and the like, and the other part is communicated with the control computer 2 through the network switch 3 and the optical fiber 4; the optical fiber 4 can perform high-voltage isolation on the transmitted signal.
In a preferred embodiment of the present invention, the main technical requirements of the device for acquiring electrons with medium energy and large beam spots and weak current of the present invention are as follows: the energy is continuously adjustable within the range of 10keV-300 keV; the beam intensity is continuously adjustable within the range of 1.3nA-1.3 mA; the diameter of the beam spot is more than or equal to 100mm; the beam current non-uniformity is less than or equal to +/-10%; the energy instability is less than or equal to 0.1% h.
In this embodiment, the beam expansion solenoid 401 is used to make the electron flow converge and then diffuse rapidly, and the first beam limiting diaphragm 402 and the second beam limiting diaphragm 403 are used to block the peripheral electron flow and only allow the central electron to pass through. Among other things, the purpose of diffusion is to improve the uniformity of the beam and to attenuate the beam intensity of the beam. According to the characteristic that the cross section distribution of the electron beam has Gaussian distribution, the beam with a relatively uniform beam center part is selected and led out. The technical parameters of the beam expanding solenoid 401 are calculated using the gaussian distribution formula:
Wherein: z is beam density;
When x is zero, Z is the maximum value, which represents the maximum point of beam current density.
If the beam non-uniformity is less than or equal to + -10%, a minimum point of the beam density needs to be found so that
(Zmax-Zmin)/(Zmax-Zmin)＝0.1
Solving the above equation gives a value of x of 0.6335 sigma. Therefore, the technical requirement that the beam current nonuniformity is less than or equal to +/-10% can be met in the interval of-0.6335 sigma < x < 0.6335 sigma.
According to the technical requirement that the beam spot diameter is greater than or equal to 100mm, the beam spot diameter is taken to be 100mm, and the calculation is combined by 0.6335σ=50mm, so that σ is approximately 79mm. It is found that the ratio of the beam current in the interval-0.6335 sigma < x < 0.6335 sigma to the total beam current is about 73.6%.
According to the technical requirement that the beam intensity is continuously adjustable within the range of 1.3nA-1.3mA, taking the beam intensity as 1.3mA, the minimum emission current of the electron gun 200 is calculated according to the following formula: 1.3mA/0.736 = 1.8mA. It is found that the ratio of the beam current to the total beam current in the interval-2σ < x < 2σ is about 97.7%. The beam current in this interval is generally considered as the total beam current, and after beam expansion by the beam expansion solenoid 401, the beam current diameter before the first beam limiting diaphragm 402 is: 4σ≡79mm =316 mm.
Further, as shown in fig. 5, the beam expansion principle of the beam expansion solenoid 401 is that the focal point 413 of the beam expansion solenoid 401 has a focal length f, the beam expansion distance L, the convergence angle θ, the beam radius before the beam expansion R1, the radius of the first beam limiting diaphragm 402 after the beam expansion distance L RT, and the beam spot after the beam expansion R2. According to the technical requirements, taking r1=5 mm and r2=158 mm, R2/r1=158/5=31.6. Choosing f=30 mm, then l=948 mm according to L/f=r2/R1.
It follows that the convergence angle θ= arctanR/l=arctan 158/948≡9.46 °.
In summary, the beam expansion solenoid 401 is a hollow solenoid, the length of the hollow solenoid is 100mm, the focal length of the hollow solenoid is 30mm, the magnetic rigidity of electrons with the energy of 300keV is 21 gauss-meter, and the highest magnetic field intensity in the center of the beam expansion solenoid 401 can be calculated to be 800 gauss, so that the use requirement can be met.
The foregoing description is only illustrative of the preferred embodiments of the present invention and is not to be construed as limiting the scope of the invention, and it will be appreciated by those skilled in the art that equivalent substitutions and obvious variations may be made using the description and drawings, and are intended to be included within the scope of the present invention.
Claims (7)
1. The device for acquiring the medium-energy large-beam spot weak-current electrons is characterized by comprising the following specific components:
An electron gun for generating an electron stream;
an acceleration tube connected to the electron gun for accelerating the electron flow to obtain a beam having a certain energy;
The beam line is arranged at the outlet of the accelerating tube and is used for processing the beam current according to a processing device arranged on the beam line so as to obtain a target beam current;
The processing device comprises:
The beam expanding solenoid is used for releasing the focused beam to realize the beam expanding of the beam;
the first beam limiting diaphragm is arranged at the outlet of the beam expanding solenoid and is used for intercepting the beam at the edge position to obtain a target beam at the central area, and the aperture of the first beam limiting diaphragm is consistent with the beam spot diameter of the target beam;
The second beam limiting diaphragm is arranged at the outlet of the first beam limiting diaphragm and is used for forming a vertical path with the first beam limiting diaphragm to acquire the target beam which is emitted vertically, and the aperture of the second beam limiting diaphragm is consistent with the beam spot diameter of the target beam;
The beam measuring module is arranged on the beam line and is used for detecting the beam intensity, the uniformity and the total beam flow of the beam;
The high-pressure steel barrel is arranged outside the electron gun and the accelerating tube and is filled with insulating gas, and is used for providing a stable use environment for the electron gun and the accelerating tube;
the beam measuring module comprises:
the flange first cylinder is arranged between the accelerating tube and the beam expanding solenoid and is used for measuring the beam intensity of the beam before beam expansion;
The terminal uniformity instrument is arranged between the first beam limiting diaphragm and the second beam limiting diaphragm and is used for measuring the uniformity and the total beam flow of the target beam;
Still include in the high-pressure steel drum:
The voltage doubling rectifying column is arranged on the bottom flange of the high-voltage steel barrel and used for providing a negative high-voltage power supply for the cathode of the electron gun;
The negative high-voltage platform is arranged above the voltage doubling rectifying column and is used for installing power supply equipment for supplying power to a cathode, a grid and an anode of the electron gun;
The isolation transformer is arranged on the top flange of the high-voltage steel drum and is used for supplying power to the power supply equipment;
The beam line is also provided with a vacuum chamber for providing a vacuum environment for electron beam current;
the beam line is also provided with a vacuum gauge for monitoring the vacuum pressure in the vacuum chamber;
the wire harness is also provided with a bleed valve for detecting leakage and inflating the vacuum chamber;
the binding wire is also provided with a plate valve for protecting a molecular pump arranged on the binding wire;
The beam line is also provided with an electromagnetic valve for carrying out pipeline conversion on a front-stage pump arranged on the beam line;
and the beam line is also provided with an oil stain separator for removing residual oil vapor in the vacuum chamber and purifying the vacuum chamber.
2. The acquisition device of claim 1, wherein the harness is peripherally wrapped with a shielding cylinder for shielding external magnetic field interference.
3. The acquisition device according to claim 1, wherein the acquisition device is installed in accordance with a geomagnetic field direction of an installation site to reduce interference of an external transverse magnetic field perpendicular to the beam direction.
4. The acquisition device of claim 1, wherein the electron gun employs a pure tungsten wire as a cathode of the electron gun.
5. The acquisition device of claim 1, wherein the acceleration tube is an isocratic acceleration tube.
6. The acquisition device according to claim 1, characterized in that the adjustment of the beam intensity of the target beam comprises adjusting the temperature of the cathode of the electron gun, and/or adjusting the voltage of the grid of the electron gun, and/or adjusting the focusing magnetic field of the beam expanding solenoid.
7. The acquisition device of claim 1, wherein the technical parameters of the beam expansion solenoid are calculated according to a gaussian distribution formula based on the parameters of the target beam.
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| CN115942587A (en) * | 2022-03-28 | 2023-04-07 | 中国电力科学研究院有限公司 | Beam modulation device and quantum current generation system with same |
| CN116347740B (en) * | 2023-03-08 | 2023-10-20 | 中子高新技术产业发展(重庆)有限公司 | Neutron treatment beam transmission system |
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| CN107318213A (en) * | 2017-07-06 | 2017-11-03 | 复旦大学 | The experimental provision of high electric conduction |
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| US3453482A (en) * | 1966-12-22 | 1969-07-01 | Varian Associates | Efficient high power beam tube employing a fly-trap beam collector having a focus electrode structure at the mouth thereof |
| JPH08241678A (en) * | 1995-03-06 | 1996-09-17 | Ryuji Ozawa | Electron gun for cathode-ray tube |
| US6922455B2 (en) * | 2002-01-28 | 2005-07-26 | Starfire Industries Management, Inc. | Gas-target neutron generation and applications |
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