A method and apparatus for pulsed of a high-current beam of a cyclotron

Abstract

The application discloses a kind of cyclotron high-current beam pulsing method and device, the device includes along the ion source to accelerator direction, it is arranged on the beam cutter A of accelerator beam injection line, beam cutter B, and it is arranged on the stripping film of accelerator beam outlet, the stripping film that is arranged on the accelerator beam outlet, stripping off n overlapping pulse beam at the same time;The method comprises: when n+m turns of beam bunch in a period of beam cutter A have 4*n high-frequency period beam bunch enter cutter B, utilize beam cutter B to realize in a pulse period, n high-frequency period beam bunch can pass, and the remaining n*3 high-frequency period beam bunch cannot pass;Overlapping of n turns of pulse beam is realized at stripping film, so that stripping film strips n overlapping pulse beam negative hydrogen beam bunch at a time, and the beam current intensity is increased by n times.The application finally realizes peak current intensity pulse beam, and compared with prior art current intensity, it is increased by nearly 20 times.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of accelerators, and particularly relates to a method and device for pulsed beam of strong current of a cyclotron. BACKGROUND

[0002] The 100 MeV strong current proton cyclotron is the first cyclotron in the world to carry out research on pulsed beam of MHz-level repetition frequency based on a stripping extraction type cyclotron at a 100 MeV energy region. Such pulsed beam with super-short time peak current has very important applications in research fields such as nuclear data measurement and nuclear physics test. The proton radiography technology based on the cyclotron can provide multiple three-dimensional dynamic process images at multiple times and in multiple directions due to the multi-pulse capability of the proton accelerator and the proton beam separation technology, thereby realizing real-time continuous imaging of the dynamic change process of the research target.

[0003] The difficulty in realizing the pulsed beam with super-short time peak current lies in that both the pulsed beam with super-short time and the pulsed beam with peak current or high current should be realized. The existing technology can only realize the pulsed beam with ordinary current but cannot realize the pulsed beam with high current. One of the reasons is that the existing technology realizes the pulsed beam by extracting single-turn beam in the extraction region, and the current of the single-turn beam is limited, so the pulsed beam with enhanced current cannot be obtained. Another reason is that the existing technology uses a beam cutter to realize the pulsed beam. The cutter can only control the beam of each turn of the accelerator to have beam in a high-frequency period and have no beam in other periods, thereby forming the micro-pulsed beam, but cannot control the accelerator to have beam in n turns and have no beam in m turns, so the macro-pulse cannot be formed. Thirdly, the pulsed beam of the existing technology is continuous between turns. Even if the method of turn overlap extraction is used, the interval time between the front and rear turns reaching the turn overlap is too short, so the interval time interval of the extraction is too short, and the pulsed beam cannot be formed. SUMMARY

[0004] The present application is proposed to solve the problems in the prior art, and provides a method and device for pulsed beam of strong current of a cyclotron, which aims to solve the problem that the prior art can only realize the pulsed beam with ordinary current but cannot realize the pulsed beam with high current.

[0005] The present application adopts the following technical solutions to solve the technical problems:

[0006] The application relates to a kind of cyclotron high-current beam pulsing devices, which comprises beam cutters A and B arranged on the beam injection line of the accelerator along the direction from the ion source to the accelerator, and a stripping film arranged at the beam outlet of the accelerator, characterized in that the stripping film arranged at the beam outlet of the accelerator can strip n overlapping pulse beams at the same time, wherein the pulse beam refers to the continuous n turns of beam in the accelerator and the continuous m turns of no beam by the beam cutter A; and the beam cutter B makes one high-frequency period of each of the n turns have beam and the other high-frequency periods have no beam; when the beam cutters work, two-stage scanning voltages are applied to the cutting plates of the beam cutters A and B, and the scanning voltage at the two ends of the beam cutter A is a square wave signal, and the scanning voltage at the two ends of the beam cutter B is a sine signal.

[0007] Further, the cutter A realizes the pulse beam period T chopperA , which includes m+n turns of beam, and specifically, when the beam passes through the center of the cutter A, the beam is deflected at the high level of the square wave to cause the beam to fail to pass through the cutting hole; at the low level of the square wave, the beam is transmitted backward freely through the cutting plate and the cutting hole, and the beam passing through the cutting hole forms a pulse beam. chopperA

[0008] Further, the pulse beam period T chopperA of the cutter A is consistent with the square wave period of the cutter A, and if the accelerator is a four-harmonic accelerator, the beam period T c of one turn in the cyclotron is 4 times the high-frequency period T RF , and the relationship between the pulse beam period T chopperA and the high-frequency period is as follows: the pulse beam period T chopperA = Tc*(m+n), and T chopperA = 4*T RF *(n+m).

[0009] Further, the cutter B makes the beam pass through the cutting hole at two zero-voltage positions in the scanning cutting period of one sine wave, and the two zero-voltage positions are the voltage positions of 0 degrees and 180 degrees; the beam is cut by the rear selection slit at other times, so that two beam pulses are generated in the scanning period T chopperB of the cutter B, one beam pulse is generated at the voltage position of 0 degrees in the first half period of the cutter B, and one beam pulse is generated at the voltage position of 180 degrees in the second half period of the cutter B, and the pulse beam with the required pulse width can be obtained by selecting the appropriate slit width. ​

[0010] Furthermore, one scan cycle T of cutter B chopperB The corresponding beam's rotation period T in the cyclotron c T times the period T of the beam completing one revolution in the cyclotron. c It is a high-frequency period T RF Therefore, the scanning voltage cycle of cutter B is 4 times that of the previous one, which is T. chopperB =8*T RF Half a scan cycle T of cutter B chopperB It is 4 times the high-frequency period, which is T. chopperB / 2=4*T RF .

[0011] Furthermore, in the first half of the cycle of cutter B, only one bundle in the high-frequency cycle at 0 degrees voltage is allowed to pass through, while the other three bundles in the high-frequency cycle at non-0 degrees voltage are cut off; in the second half of the cycle of cutter B, only one bundle in the high-frequency cycle at 180 degrees voltage is allowed to pass through, while the other three bundles in the high-frequency cycle at non-180 degrees voltage are cut off.

[0012] Furthermore, the period T of one pulse beam from cutter A chopperA A bunch of n loops is allowed to pass through, and this n-loop bunch in cutter A represents n*4 high-frequency cycles T. RF The bundle within the cutter A is allowed to pass through; when a bundle of n turns from cutter A enters cutter B, it means that a bundle of 1 turn is only allowed to pass through cutter B for 1 high-frequency cycle, while a bundle of n turns is only allowed to pass through cutter B for n high-frequency cycles T. RF The bundle passed through.

[0013] A method for pulsed high-current beam in a cyclotron accelerator, characterized by comprising the following steps:

[0014] Step 1: Set the scanning voltage across beam cutter A to a square wave signal and the scanning voltage across beam cutter B to a sine wave signal.

[0015] Step 2: Use beam cutter A to achieve a period T of 1 pulse beam chopperA There are n loops of beam clusters that can enter the accelerator orbit, while the remaining m loops of beam clusters cannot enter the accelerator orbit; each loop of beam cluster corresponds to 4 high-frequency cycles, so for one pulse beam cycle, beam cutter A can allow 4*n high-frequency cycles of beam clusters to pass through.

[0016] Step 3: When the 4*n high-frequency cycle beams from beam cutter A enter cutter B, beam cutter B is used to achieve one scan cycle T. chopperBIn the middle, n high-frequency period beam bundles can pass through, and the remaining n*3 high-frequency period beam bundles cannot enter the accelerator track, that is, in a pulse period, n high-frequency period beam bundles can pass through, and the remaining n*3 high-frequency period beam bundles cannot enter the accelerator track;

[0017] Step four: overlapping n turns of the pulsed beam at the peeling film to make the peeling film peel off n turns of the overlapped pulsed beam negative hydrogen beam bundles at one time, and the beam current is increased by n times.

[0018] Further, the specific process of step six is as follows:

[0019] 1) Set the number of turns n of the accelerator extraction zone, and the number of turns n is neither affected by the state of particle acceleration nor suitable for extracting as many turns of the overlapped beam as possible;

[0020] 2) The width of the peeling film is selected to be just enough to cover the width of n turns of the overlapped beam;

[0021] 3) The peeling film peels off the negative hydrogen particles of the n turns of the overlapped beam at one time;

[0022] 4) Each negative hydrogen particle in the n turns of the overlapped beam is converted into a proton after peeling off two electrons, and n proton beam bundles are extracted along the extraction track at the same time, realizing that the proton beam extraction current is increased by n times.

[0023] Further, the size of T1 of the cutter A can be set according to the interval of the pulses, and when it is necessary to increase the interval between the pulses, T1 is increased.

[0024] Further, the number of turns n of the accelerator extraction zone is calculated by a beam dynamics software, and the n turns of the overlapped pulsed beam that can meet the energy setting requirements is calculated by the software.

[0025] Advantages and effects of the present application

[0026] 1) The present application combines the cutter A and the cutter B organically, combines the cutter A, the cutter B and the extraction zone peeling film organically, combines the extraction zone peeling film and the n turns of the overlapped beam that meets the dynamics requirements, and finally realizes the peak current pulsed beam, which is compared with the single turn beam that can be extracted in the prior art, and the current is increased by nearly 20 times.

[0027] 2) The present application solves the technical problem of high-current pulsed beam extraction of multiple turns that technicians in the field have been eager to solve but have failed to solve, and the present application solves the technical problem of high-current pulsed beam extraction, which has substantial features and significant progress. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1The schematic diagram of the pulse beam cutter is arranged on the beam injection line according to the present application;

[0029] Figure 2 The schematic diagram of the cutting beam effect of two beam cutters according to the present application;

[0030] Figure 3 The schematic diagram of the scanning voltage of the beam cutter A according to the present application is a square wave signal;

[0031] Figure 4 The schematic diagram of the scanning voltage of the beam cutter B according to the present application is a sine wave signal;

[0032] Figure 5 The schematic diagram of the structure of the beam cutter A and the beam cutter B according to the present application. DETAILED DESCRIPTION

[0033] Design principle of the present application

[0034] Design principle of realizing the peak current pulse beam. The present application has two difficulties, the first difficulty is to realize the peak current, and the second is to realize the peak current pulse beam. The difficulty of realizing the peak current is to adopt the method of leading out multiple turns, which cannot affect the acceleration state of the particles and also wants to lead out as many turns as possible, and find a balance point: too many turns will lead out the particles being accelerated or the particles whose energy has not reached the required requirements, and the fewer turns, the peak current cannot be reached. Although the prior art can realize the pulse beam, it cannot realize the peak current pulse beam. If the prior art realizes the peak current beam, it must not lead out the pulse beam. The reason is that the prior art only leads out the single turn pulse beam, even if the multiple turns pulse beam is led out, the shape of the beam led out is not the pulse beam but the non-pulse beam.

[0035] The method for solving the first difficulty is: the number of stripping turns and the energy range of the strippable beam are calculated by beam dynamics orbit tracking software, the number of the stripping turns is neither too much nor too little, for example, if the total number of accelerator beam turns is 400, the number of turns introduced is 20, the 20 turns of beam bunches with different energies and different current strengths can be introduced at the stripping film at the same time, the greater the energy, the closer to the outer radius of the glass film, but the premise of introducing the 20 turns of beam is that the energy of the 20 turns of particles has reached the predetermined requirement, so they can be introduced. If the traditional method is used, only the energy of the outermost turn of the beam can meet the requirement. If the energy and current strength of the 20 turns of beam are to meet the set requirement, it is related to the phase of the beam passing through the accelerating gap each time, the magnetic field isochronism, the transverse focusing state and the like, by adjusting the phase of the beam passing through the accelerating gap each time, the magnetic field isochronism, the transverse focusing, the energy of the 20 turns of beam can all meet the predetermined requirement, even if the energy of each turn of the 20 turns of beam is different. The magnetic field isochronism is that the time for the innermost turn and the outermost turn of the accelerator beam to complete one turn is equal; the transverse focusing refers to the radial focusing and the axial focusing, the radial focusing is that the accelerator beam orbit diverges to the left and right sides of the beam orbit center point, and the axial focusing is that the accelerator beam orbit diverges to the upper and lower sides of the beam orbit center point.

[0036] The method for solving the second difficulty is: two beam cutters are used to realize the peak current strength pulse beam, for example Figure 1As shown. Existing technology uses only one cutter B, which pulses the beam by passing a bundle of particles through the cutter B every few high-frequency cycles. For example, there is a beam in one of the four high-frequency cycles, and no beam in the other three. However, because cutter A is not used, each beam loop contains a pulsed beam, meaning the pulsed beam is continuous. If one cutter B is used, although 20 beam loops can be extracted, the first 20 loops are followed immediately by the second 20 loops, which are then at the stripping film position. The time interval between the first and second 20 loops is very short, so the third 20 loops begin before a pulse is formed. As this continues, the shape of the stripped multi-loop beam should be wave-shaped rather than pulse-shaped because there is not enough time interval between the previous 20 loops and the next 20 loops to form a pulsed beam. To address the issue of increasing the time interval, this invention adds a cutter A near the ion source in front of cutter B. Cutter A differs from cutter B in that its T1 period allows n beam passes, while its T2 period does not allow m beam passes. Only the allowed n beam passes can enter cutter B. Ultimately, the multiple pulsed beams extracted from the accelerator extraction region are all pulsed beams generated by cutter B. The values ​​of T1 and T2 can be set according to the pulse width. When a larger pulse interval is needed, T1 is increased; when a wider pulse is needed, T2 is increased. However, the values ​​of T1 and T2 are determined based on the ability to form a pulsed beam.

[0037] Based on the above-mentioned inventive principles, this invention designs a cyclotron high-current beam pulsed device.

[0038] A cyclotron high-current beam pulsed device, such as Figures 1-5 As shown, the device includes a beam cutter A and a beam cutter B arranged along the accelerator beam injection line from the ion source to the accelerator, and a stripping film arranged at the accelerator beam outlet. The device is characterized in that the stripping film at the accelerator beam outlet can strip away n overlapping pulsed beams simultaneously. The pulsed beam refers to the beam cutter A causing n consecutive cycles of beam flow and m consecutive cycles of no beam flow in the accelerator; the beam cutter B causes one high-frequency cycle of each of the n cycles to have beam flow, while the other high-frequency cycles do not. When the beam cutter is working, scanning voltages are applied to the cutting plates of beam cutter A and cutter B respectively. The scanning voltage across beam cutter A is a square wave signal, and the scanning voltage across beam cutter B is a sine wave signal.

[0039] Supplementary Note 1

[0040] The stripping film is a carbon stripping film with a large thickness and high density, which can achieve 99.9% stripping of negative hydrogen ions.

[0041] Furthermore, such as Figure 2 As shown, the cutter A is implemented during the period T of the pulse beam. chopperA In this scenario, assuming that m loops of the beam cannot enter the accelerator orbit within time T1, and n loops of the beam can enter the accelerator orbit within the remaining time T2, the period T of the pulse beam is... chopperA Including m+n loops of beam, specifically: when the beam passes through the center of cutter A, the beam is deflected when the square wave is at a high level, causing the beam to be unable to pass through the cutting hole; when the square wave is at a low level, the beam will freely pass through the cutting plate and the cutting hole and propagate backward, and the beam passing through the cutting hole forms a pulse beam.

[0042] Furthermore, the pulse beam period T of the cutter A chopperA Consistent with the square wave period of cutter A, if the accelerator is a fourth harmonic accelerator, then the period T of the beam completing one revolution in the cyclotron is... c It is a high-frequency period T RF If the pulse beam period is 4 times that of the pulse beam, then there exists a pulse beam period T. chopperA Relationship with high-frequency period: Pulse beam period T chopperA =Tc*(m+n), T chopperA =4*T RF *(n+m).

[0043] Supplementary Note 2

[0044] Cutter A allows n turns of beam current to pass through and does not allow m turns of beam current to pass through. Each turn of the beam current is four times the high-frequency period, therefore the pulse beam period T chopperA =Tc*(m+n), where T c It is the period T of the beam completing one revolution in the cyclotron. c .

[0045] Furthermore, such as Figure 4 As shown, in one sinusoidal scanning cutting cycle, the beam of the cutter B passes through the cutting aperture at two zero-voltage points on the outward and return journeys, namely at voltages of 0 degrees and 180 degrees. During the remaining time, the beam is cut off by the subsequent selective slit. Therefore, in one scanning cycle T of the cutter B... chopperB Two beam pulses will be generated. In the first half of the cycle of cutter B, one beam pulse will be generated at its 0-degree voltage. In the second half of the cycle of cutter B, one beam pulse will be generated at its 180-degree voltage. By selecting an appropriate slit width, the required pulse beam width can be obtained.

[0046] Furthermore, one scan cycle T of cutter B chopperB The corresponding beam's rotation period T in the cyclotron c2 times of the high frequency period T c is 4 times of the high frequency period T RF , so one scanning voltage period of the cutter B is T chopperB = 8*T RF , and half scanning period T chopperB of the cutter B is 4 times of the high frequency period, that is, T chopperB / 2 = 4*T RF .

[0047] Supplementary Note 3:

[0048] Figure 4 The dotted curve is one period of the cutter B, and the solid curve is the high frequency period. It can be seen that one period of the cutter B corresponds to 8 high frequency periods, and since one turn of the beam corresponds to 4 high frequency periods, one period of the cutter B corresponds to 2 turns of the beam.

[0049] Further, in the first half period of the cutter B, only one beam group in the high frequency period at 0 degree voltage is allowed to pass, and the beam groups in the other 3 high frequency periods at non-0 degree voltage are cut off; in the second half period of the cutter B, only one beam group in the high frequency period at 180 degree voltage is allowed to pass, and the beam groups in the other 3 high frequency periods at non-180 degree voltage are cut off.

[0050] Supplementary Note 4:

[0051] As shown in Figure 4 , if one period of the cutter B is divided into the first half and the second half, 0 degree is the starting point of the first half period, and 180 degree is the starting point of the second half period.

[0052] Further, in the period T chopperA of one pulse beam of the cutter A, n turns of beam groups are allowed to pass, which means that in the cutter A, n*4 high frequency periods T RF of beam groups are allowed to pass; when the n turns of beam groups of the cutter A enter the cutter B, it means that in the cutter B, one turn of beam groups is allowed to pass in only one high frequency period, and n turns of beam groups are allowed to pass in n high frequency periods T RF .

[0053] A method for pulse beam of a strong current beam of a cyclotron, characterized in that the method comprises the following steps:

[0054] Step 1, setting the scanning voltage at both ends of the beam cutter A as a square wave signal, and setting the scanning voltage at both ends of the beam cutter B as a sine wave signal;

[0055] Step 2, using the beam cutter A to realize that in the period T chopperA of one pulse beam, n turns of beam groups are allowed to pass.chopperA The n-circled beam bundle can enter the accelerator track, and the m-circled beam bundle cannot enter the accelerator track; each circled beam bundle corresponds to 4 high-frequency periods, and the beam cutter A can pass 4*n high-frequency period beam bundles in a pulse beam period;

[0056] Step three: when the 4*n high-frequency period beam bundles of the beam cutter A enter the beam cutter B, the beam cutter B is used to realize that n high-frequency period beam bundles can pass in a scanning period T chopperB The n high-frequency period beam bundles can pass, and the n*3 high-frequency period beam bundles cannot enter the accelerator track, that is, n high-frequency period beam bundles can pass in a pulse period, and n*3 high-frequency period beam bundles cannot enter the accelerator track;

[0057] Step four: the n-circled pulse beam is overlapped at the stripping film, so that the stripping film strips the n-circled overlapped pulse beam negative hydrogen beam bundle at one time, and the beam current is increased by n times.

[0058] Further, the step six is specifically as follows:

[0059] 1) Set the circle overlap number n of the accelerator extraction area, and the circle overlap number n is neither affected the state of particle acceleration nor suitable for extracting as much multi-circle overlapped beam as possible;

[0060] 2) The width of the stripping film is selected to be just the width of the n-circled overlapped beam bundle;

[0061] 3) The stripping film strips the negative hydrogen particles of the n-circled overlapped beam bundle at one time;

[0062] 4) Each negative hydrogen particle in the n-circled overlapped beam bundle is converted into a proton after stripping two electrons, and n proton beam bundles are extracted along the extraction track at the same time, so that the proton beam extraction current is increased by n times.

[0063] Further, the size of T1 of the cutter A can be set according to the interval of the pulse, and T1 is increased when the interval between the pulses needs to be increased.

[0064] Further, the circle overlap number n of the accelerator extraction area is calculated by a beam dynamics software, and the n-circled overlapped pulse beam that meets the energy setting requirement is calculated by the software.

[0065] It should be emphasized that the above specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the above embodiments without creative contribution after reading the present specification, as long as the modifications are within the scope of the claims of the present application.

Claims

1. A device for pulsing a high-current beam of a cyclotron, the device comprising a beam cutter A, a beam cutter B, arranged on a beam line of the cyclotron in a direction from an ion source to the cyclotron, and a stripping foil arranged at an exit of the beam line of the cyclotron, characterized in that: The stripping film is arranged at the exit of the accelerator beam current, which can strip n overlapping pulse beams at the same time, the pulse beam refers to the beam current through the beam cutter A, which makes the continuous n turns of the accelerator have beam current and the continuous m turns have no beam current; through the beam cutter B, in the multiple high frequency periods of each of the n turns, one has beam current and the others have no beam current; when the beam cutter works, the scanning voltage is applied to the two stages of the cutting plate of the beam cutter A and the beam cutter B, the scanning voltage at the two ends of the beam cutter A is a square wave signal, and the scanning voltage at the two ends of the beam cutter B is a sine signal.

2. The device for pulsed operation of high-current beams of a cyclotron according to claim 1, characterised in that: The cutter A is implemented in the cycle T of the pulse beam chopperA In the cycle T of the pulse beam, assuming that m turns of the beam bundle cannot enter the accelerator track in T1 time, n turns of the beam bundle can enter the accelerator track in T2 time chopperA The cycle T of the pulse beam includes m+n turns of the beam bundle, specifically: when the beam passes through the center of the cutter A, the beam is deflected at the high level of the square wave, so that the beam cannot pass through the cutting hole; at the low level of the square wave, the beam can freely pass through the cutting plate and the cutting hole and be transmitted backward, and the beam passing through the cutting hole forms a pulse beam.

3. The device for pulsed operation of high-current beams of a cyclotron according to claim 2, characterised in that: The pulse beam period T of the said cutter A chopperA Consistent with the square wave period of the cutter A, if the accelerator is a four harmonic accelerator, the beam flow is in the period T of a turn of the cyclotron c The high frequency period T RF Is 4 times, then there is a pulse beam period T chopperA The relationship between the high frequency period and the pulse beam period T chopperA =Tc*(m+n), T chopperA =4*T RF *(n+m).

4. The apparatus of claim 1, wherein: the beam pulse is a beam pulse of a high current beam of a cyclotron. The said cutter B, in a scanning cutting period of a sine wave, the beam passes the cutting hole at two zero voltage positions of the forward and return, which are the 0 degree and 180 degree voltage positions; at other time, the beam is cut off by the following selection slit, thus, in a scanning period T of the cutter B chopperB two beam pulses are generated, one in the former half period of the cutter B at the 0 degree voltage position and the other in the latter half period of the cutter B at the 180 degree voltage position, by selecting the proper slit width, the pulse beam with the required pulse width can be obtained.

5. The cyclotron high-current beam pulsed device according to claim 4, characterized in that: 1 scan period T of the cutter B chopperB corresponding to 2 times the period T of the beam circulating in the cyclotron c corresponding to 2 times the period T of the beam circulating in the cyclotron c is 4 times the high frequency period T RF , so that one scan voltage period T chopperB =8*T RF of the cutter B is 8 times the high frequency period T chopperB , so that half a scan voltage period T chopperB / 2=4*T RF of the cutter B is 4 times the high frequency period T 6. The high-current beam pulsing device of the cyclotron according to claim 5, characterized in that: In the first half of the period of the cutter B, only one beam group in the high frequency period at the voltage of 0 degrees is allowed to pass, and the beam groups in the other three high frequency periods at the voltage of 0 degrees are cut off; in the second half of the period of the cutter B, only one beam group in the high frequency period at the voltage of 180 degrees is allowed to pass, and the beam groups in the other three high frequency periods at the voltage of 180 degrees are cut off.

7. The apparatus of claim 5, wherein: the beam pulse is a beam pulse of a high current beam of a cyclotron. The period T of one pulse beam of the cutter A chopperA The n-turn bundle is allowed to pass through, which means n*4 high frequency periods T in the cutter A RF The bundle is allowed to pass through within 1 turn; when the n-turn bundle of the cutter A enters the cutter B, it means that the 1-turn bundle is only allowed to pass through the bundle within 1 high frequency period in the cutter B, and the n-turn bundle is only allowed to pass through the bundle within n high frequency periods T in the cutter B RF The bundle passes through within n periods T.

8. A method for pulsing a beam of high current in a cyclotron based on the device for pulsing a beam of high current in a cyclotron according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: Step one, the scanning voltage at the two ends of the beam cutter A is a square wave signal, and the scanning voltage at the two ends of the beam cutter B is a sine signal; Step two: use beam cutter A to realize 1 pulse beam cycle T chopperA The beam bundle with n circles can enter the accelerator orbit, and the beam bundle with m circles cannot enter the accelerator orbit; wherein each circle of the beam bundle corresponds to 4 high-frequency periods, and the beam cutter A can pass the beam bundle with 4*n high-frequency periods in a pulse beam cycle. Step three: when the 4*n high-frequency period bunches of beam current cutter A enter cutter B, use beam current cutter B to realize that n high-frequency period bunches can pass through in one scanning period T chopperB In one pulse period, n high-frequency period bunches can pass through, and n*3 high-frequency period bunches cannot enter the accelerator orbit. Step four: the overlapping of the n turns of the pulse beam is realized at the stripping film, so that the stripping film strips the n turns of the overlapping pulse beam negative hydrogen beam group at one time, and the beam current is increased by n times.

9. The method of claim 8, wherein: the beam pulse is a single shot beam pulse. The specific process of step four is as follows: 1) Set the number of overlapping turns n of the accelerator extraction area, the size of the number of overlapping turns n does not affect the state of particle acceleration, and is suitable for extracting as many overlapping turns of beam current as possible; 2) The width of the stripping film is selected to be just the width of the n turns of overlapping beam groups; 3) The stripping film strips the negative hydrogen particles of the n turns of overlapping beam groups at one time; 4) Each negative hydrogen particle in the n turns of overlapping beam groups is converted into a proton after stripping two electrons, and n proton beam groups are extracted along the extraction orbit at the same time, realizing the n-fold increase of the proton beam extraction current.

10. The method of claim 8, wherein: The size of T1 of the beam cutter A can be set according to the interval of the pulse, when it is needed to increase the interval between the pulses, T1 is increased. ​ 11. The method of claim 9, wherein: The number of overlapping turns n of the accelerator extraction area is calculated by a beam dynamics software, and the n turns of overlapping pulse beams that meet the energy setting requirements are calculated by the software. ​

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