Double cutter power supply differential device and method for obtaining ns-level pulse beam width

Abstract

The invention discloses a dual-cutter power supply differential device and a method for obtaining a ns-level pulse beam width. The device comprises: a cutting plate of a cutter bipolar plate of an accelerator pulse system is connected to a periodically changing set voltage V1, and the other cutting plate is connected to a periodically changing set voltage V2, a voltage V3=V1-V2 between the two cutting plates, the voltages of V2 and V1 are opposite, and W3>V1>Vt, and V1 and V2 have a phase difference φ; the method comprises: setting voltage values ​​V1, V2, V3, Vt, a phase difference φ between V1 and V2, and an applied beam pulse width W3; a periodically changing set voltage V1 is connected to one cutting plate, and a periodically changing set voltage V2 is connected to the other cutting plate; the phase difference between the voltages of the dual cutting plates reaches a set value φ; a pulse with a rising edge and a falling edge both less than 1 ns is obtained; the invention solves the problem that the pulse width provided by a single switch high-voltage power supply in the world can only be maintained at more than 20 ns and cannot meet the demand for an applied pulse beam width at the ns level.

Description

Technical Field

[0001] The invention belongs to the technical field of proton accelerators, and in particular relates to a double-cutter power supply differential device and a method for obtaining a ns-level pulse beam width. Background Art

[0002] A pulsed beam refers to a beam that exists for a short period of time in a cycle and has no beam for most of the time. It is indispensable in fields such as nuclear data measurement. In order to ensure that the pulsed beam provided by the accelerator meets the needs of various applications, a cutter is generally used internationally to convert a continuous beam into a pulsed beam with a certain repetition frequency.

[0003] At present, the cutters used in the accelerator pulse system all use internationally standardized single-switch cutters, in which one bipolar plate is connected to the set voltage and the other is grounded. The disadvantage of this solution is that the pulse width provided by this internationally standardized single-switch high-voltage power supply can only be maintained above 20ns, while some applications require a pulse beam width of the order of ns, and existing products cannot meet the needs of these applications. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention proposes a dual-cutter power supply differential device and a method for obtaining a ns-level pulse beam width, aiming to solve the problem that existing international standardized products cannot meet the application requirements of pulse beam width at the ns level.

[0005] In order to solve the technical problems, the present invention proposes the following technical solutions:

[0006] A dual-cutter high-voltage switch power supply differential device, characterized in that: one of the cutter bipolar plates of the accelerator pulse system is connected to a periodically changing set voltage V1, and the other cutter is connected to a periodically changing set voltage V2, the voltage between the two cutters V3 = V1-V2, the voltages of V2 and V1 are opposite, and V1 is greater than V t Less than V3, V t The threshold voltage for deflecting the beam and preventing it from passing through the beam slit; V1 and V2 have a phase difference φ, and the applied beam pulse width W3 is the part where both the rising and falling edges of V3 are smaller than Vt. The applied beam pulse width W3 is reduced to: the pulse width of V1 minus the width of the phase difference between V1 and V2.

[0007] The dual cutter high-voltage switching power supply is a fast pulse square wave with a repetition frequency of MHz and a maximum voltage of 8kV, and a 4kV square wave high-voltage switching power supply with a repetition frequency of 1-3MHz and opposite positive and negative loaded on the cutter bipolar plate.

[0008] The absolute values ​​of the voltages V2 and V1 on the bipolar plate of the cutter are equal, or the absolute values ​​of the voltages V2 and V1 are not equal.

[0009] The dual-cutter high-voltage switching power supply differential device obtains a fast pulse high-voltage square wave with a rising edge and a falling edge of less than 1ns, a maximum voltage of 8kV, and a repetition frequency of 3MHz between the cutting plates by means of phase differentiation.

[0010] A method for obtaining a ns-level pulse beam width, characterized in that it comprises the following steps:

[0011] Step 1, setting voltage values ​​V1, V2, V3, Vt, phase difference φ between V1 and V2, and applied beam pulse width W3;

[0012] Step 2: Connect a periodically changing set voltage V1 to one cutting plate and connect a periodically changing set voltage V2 to the other cutting plate;

[0013] The voltages of V2 and V1 are opposite, and V3>V1>Vt. Vt is exactly the threshold voltage that causes the beam to deflect and cannot pass through the slit. The voltage between the two cutting plates is V3=V1-V2

[0014] Step 3, making the phase difference between the voltages of the double cutting plates reach a set value φ;

[0015] Step 4: Obtain a fast pulse high-voltage square wave with a rising edge and a falling edge of less than 1ns, a maximum voltage of 8kV, and a repetition frequency of 3MHz;

[0016] Step 5: When the applied pulse width needs to be reduced, the phase difference φ between the double cutting plates V1 and V2 is increased; when the applied pulse width needs to be increased, the phase difference between the double cutting plates V1 and V2 is reduced.

[0017] Advantages and effects of the present invention

[0018] 1. The power supply differential device of the double cutter of the present invention achieves the effect of obtaining a fast pulse high-voltage square wave with a rising edge and a falling edge of less than 1ns, a maximum voltage of 8kV, and a repetition frequency of 3MHz between the cutting plates by organically combining the four conditions of phase difference, positive and negative opposite voltages, threshold voltage, Vt, and 2V0>V0>Vt, and supporting and relying on each other. This solves the problem that the pulse width provided by a single-switch high-voltage power supply in the world can only be maintained at more than 20ns and cannot meet the demand for the application of pulse beam width in the ns order.

[0019] 2. The present invention overcomes the prejudice of technical personnel in this field who have long used a single-switch cutting board, that is, one end of the single-switch cutting board is grounded and the other end is connected to a periodically changing voltage. It adopts a method that is not easy for technical personnel in this field to think of, that is, the cutting board at the grounded end is also connected to a voltage, and the voltage is opposite. This solves the key problem of reducing the pulse width. On this basis, the phase difference is further calculated according to the application pulse width requirements, and the condition of 2V0>V0>Vt is met. Finally, a pulse width of 1ns is achieved. Compared with the international standard of 20ns pulse width of cutters, it has achieved a leap from quantitative change to qualitative change. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of pulse beam;

[0021] Figure 2 It is the cutter principle;

[0022] Figure 3 This is the principle of the dual cutter power supply differential method. DETAILED DESCRIPTION

[0023] Principle of the Invention

[0024] 1. Design principle of conventional single switch cutter: Figure 2 As shown, it consists of a single switch cutting plate and a slit. The single switch cutting plate is composed of two cutting plates, one of which is grounded and the other is connected to a periodically changing voltage. When the beam passes through the cutting plate, it is affected by the electric field and is periodically deflected. When there is no voltage between the cutting plates, the beam can pass through the slit to form a pulse beam.

[0025] 2. The design principle of the dual switch cutter of the present invention: Figure 3 As shown, V1 in the upper right corner of the figure is Figure 3 The voltage value V0, V2 in the upper right corner of the figure is Figure 3 The voltage value is -V0, and V3 in the upper right corner of the figure is Figure 3 The voltage value is 2V0. The present invention proposes a dual cutter power supply differential solution,

[0026] 1) Connect one cutting plate to the voltage shown by the curve V0, and the other cutting plate to the voltage shown by the curve -V0. 2V0>V0>Vt, Vt is exactly the threshold voltage when the beam is deflected and cannot pass through the slit. The voltages V0 and -V0 are opposite, and the phase difference is t10-t7. At this time, the voltage between the cutting plates V3=V1-V2, and the pulse width is reduced to t12-t9.

[0027] 2) A 4kV square wave high-voltage switching power supply with a repetition frequency of 1-3MHz and opposite positive and negative currents is loaded onto the bipolar plates of the cutter of the accelerator pulse system, and a fast pulse high-voltage square wave with a rising and falling edge of less than 1ns, a maximum voltage of 8kV, and a repetition frequency of 3MHz is obtained between the cutting plates by phase differentiation.

[0028] It can be seen that the four conditions of the present invention are indispensable: phase difference, opposite voltages (V0, -V0), the threshold voltage Vt that deflects the beam and prevents it from passing through the slit, and 2V0>V0>Vt. First, the voltages must be opposite in order to reduce the pulse width through the phase difference. If the voltages of the two cutting plates are opposite, but the phase difference is zero, the pulse width after superposition can be reduced but not significantly (the change of the rising and falling edges of V3 causes a slight reduction in the pulse width). Only when a phase difference occurs can the pulse width be reduced, and the reduced pulse width is the width of the phase difference. Therefore, the phase difference and the opposite voltages are interdependent and indispensable. Second, 2V0>V0>Vt must be satisfied, V t It is the threshold voltage that just deflects the beam and prevents it from passing through the slit. If V0 is less than Vt, that is, V t Between V0 and 2V0, the pulse width generated by V0 is greater than Figure 3 The pulse width of V0 in the figure is because the lower the voltage, the smaller the deflection force of the electric field on the charge, and the wider the pulse width. When the voltage is 0, the pulse width is infinite, and there is no pulse. t Above 2V0, the beam becomes a continuous beam and no pulse beam is generated. t is the threshold voltage. If the superimposed voltage 2V0 (when V0 and -V0 voltages are equal, the superimposed voltage is 2V0, but they may not be equal) is less than V t , the beam will continuously pass through the slit and become a continuous beam. Therefore, the relationship between 2V0, V0, and Vt must satisfy the condition of 2V0>V0>Vt, and they must be interdependent and mutually supportive to produce the effect of obtaining a rising edge and a falling edge of less than 1ns between the cutting plates.

[0029] 3. V t Calculation

[0030] like Figure 2 As shown, let the cutting plate length be l, the plate voltage be V, the distance be d, the drift node length be L; the particle mass be m, the charge be q, the initial velocity be v; the particle's forward direction be the x direction, and the deflection plate direction be the y direction. If the relativistic effect is not considered, when the particle leaves the cutting plate, it is affected by the cutting plate's electric field, and the particle's velocity in the y direction is:

[0031]

[0032] The velocity remains unchanged after leaving the cutting plate, so the particle's offset at the slit is:

[0033]

[0034] When designing the cutter, the cutter voltage and slit width are determined based on the above formula and the beam line layout. For a determined slit half-width y0, the threshold voltage that deflects the beam and prevents it from passing through the slit is:

[0035]

[0036] Based on the above principle, the present invention discloses a double-cutter high-voltage switching power supply differential device.

[0037] A dual-cutter high-voltage switch power supply differential device, characterized in that: one of the cutter bipolar plates of the accelerator pulse system is connected to a periodically changing set voltage V1, and the other cutter is connected to a periodically changing set voltage V2, the voltage between the two cutters V3 = V1-V2, the voltages of V2 and V1 are opposite, and V1 is greater than V t Less than V3, V t The threshold voltage for deflecting the beam and preventing it from passing through the beam slit; V1 and V2 have a phase difference φ, and the applied beam pulse width W3 is the part where both the rising and falling edges of V3 are smaller than Vt. The applied beam pulse width W3 is reduced to: the pulse width of V1 minus the width of the phase difference between V1 and V2.

[0038] The dual cutter high-voltage switching power supply is a fast pulse square wave with a repetition frequency of MHz and a maximum voltage of 8kV, and a 4kV square wave high-voltage switching power supply with a repetition frequency of 1-3MHz and opposite positive and negative loaded on the cutter bipolar plate.

[0039] The absolute values ​​of the voltages V2 and V1 on the bipolar plate of the cutter are equal, or the absolute values ​​of the voltages V2 and V1 are not equal.

[0040] The dual-cutter high-voltage switching power supply differential device obtains a fast pulse high-voltage square wave with a rising edge and a falling edge of less than 1ns, a maximum voltage of 8kV, and a repetition frequency of 3MHz between the cutting plates by means of phase differentiation.

[0041] A method for obtaining ns-level pulse beam width of a double-cutter high-voltage switching power supply differential device, characterized in that it includes the following steps:

[0042] Step 1, setting voltage values ​​V1, V2, V3, Vt, phase difference φ between V1 and V2, and applied beam pulse width W3;

[0043] Step 2: Connect a set voltage V1 to one cutting board and a set voltage V2 to the other cutting board;

[0044] The voltages of V2 and V1 are opposite, and V1 is greater than Vt, which is exactly the threshold voltage that causes the beam to deflect and cannot pass through the slit; the voltage between the two cutting plates V3 = V1-V2

[0045] Step 3: Let the phase difference between V1 and V2 be the set value φ;

[0046] Step 4: Obtain a fast pulse high-voltage square wave with a rising edge and a falling edge of less than 1ns, a maximum voltage of 8kV, and a repetition frequency of 3MHz;

[0047] Step 5: When the applied pulse width needs to be reduced, the phase difference φ between V1 and V2 is increased; when the applied pulse width needs to be increased, the phase difference between V1 and V2 is reduced.

[0048] Embodiment 1

[0049] This scheme proposes a dual-cutter power supply differential method, which can obtain a high-voltage pulse signal of the order of ns. Figure 3 As shown in V1, the upper right corner V1 is equivalent to V0 on the voltage coordinate axis, the upper right corner V2 is equivalent to -V0 on the voltage coordinate axis, and the upper right corner V3 is equivalent to 2V0 on the voltage coordinate axis.

[0050] V3=V1-V2

[0051] At this time, the beam pulse width is t 12 -t9, reducing Δt. By adjusting Δt, a pulse beam that meets the experimental needs can be obtained, and the pulse width can be as low as ns. The principle of the double cutter power supply differential method is as follows:

[0052] like Figure 3 As shown, T is the pulse period and Vt is the threshold voltage that just deflects the beam and prevents it from passing through the slit.

[0053] The commonly used cutter scheme is: one cutting plate is connected to the voltage shown by curve V1, and the other cutting plate is grounded. At this time, the voltage is V0 from 0 to t5, drops from V0 to 0 from t5 to t7, is 0 from t7 to t11, rises from 0 to V0 from t11 to t13, and is V0 from t13 to T. The pulse width of this scheme is t12-t6.

[0054] The present invention proposes a dual-cutter power supply differential solution, where one cutting plate is connected to the voltage shown by curve V1, and the other cutting plate is connected to the voltage shown by curve V2. The voltages of V2 and V1 are opposite, and the phase difference is t10-t7. At this time, the voltage between the cutting plates V3 = V1-V2, and the pulse width is reduced to t12-t9.

[0055] It should be emphasized that the above specific embodiments are merely explanations of the present invention, and they are not limitations of the present invention. After reading this specification, those skilled in the art can make modifications to the above embodiments without any creative contribution as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A double-cutter high-voltage switching power supply differential device, characterized in that: One cutting plate of the bipolar plate of the cutter of the accelerator pulse system is connected to a periodically changing set voltage V1, and the other cutting plate is connected to a periodically changing set voltage V2. The voltage between the two cutting plates is V3 = V1-V2, the voltages of V2 and V1 are opposite, and V3>V1>Vt, V t The threshold voltage for the beam to be deflected and unable to pass through the beam slit; V1 and V2 have a phase difference φ, and the applied beam pulse width W3 is the part where both the rising and falling edges of V3 are smaller than Vt, and the applied beam pulse width W3 is reduced to: the pulse width of V1 minus the width of the phase difference between V1 and V2; The dual-cutter high-voltage switching power supply is a fast pulse square wave with a repetition frequency of MHz and a maximum voltage of 8kV, and a 4kV square wave high-voltage switching power supply with a repetition frequency of 1-3MHz and opposite positive and negative loaded on the bipolar plate of the cutter; The dual-cutter high-voltage switching power supply differential device obtains a fast pulse high-voltage square wave with a rising edge and a falling edge of less than 1ns, a maximum voltage of 8kV, and a repetition frequency of 3MHz between the cutting plates by means of phase differentiation.

2. A double-cutter high-voltage switching power supply differential device according to claim 1, characterized in that: The absolute values ​​of the voltages V2 and V1 on the bipolar plate of the cutter are equal, or the absolute values ​​of the voltages V2 and V1 are not equal.

3. A method for obtaining a ns-level pulse beam width based on a double-cutter high-voltage switching power supply differential device according to any one of claims 1 to 2, characterized in that: The following steps are involved: Step 1, setting voltage values ​​V1, V2, V3, Vt, phase difference φ between V1 and V2, and applied beam pulse width W3; Step 2: Connect a periodically changing set voltage V1 to one cutting plate and connect a periodically changing set voltage V2 to the other cutting plate; The voltages of V2 and V1 are opposite, and V3>V1>Vt. Vt is exactly the threshold voltage that causes the beam to deflect and cannot pass through the slit. The voltage between the two cutting plates is V3=V1-V2 Step 3, making the phase difference between the voltages of the double cutting plates reach a set value φ; Step 4: Obtain a fast pulse high-voltage square wave with a rising edge and a falling edge of less than 1ns, a maximum voltage of 8kV, and a repetition frequency of 3MHz; Step 5: When the applied pulse width needs to be reduced, the phase difference φ between the double cutting plates V1 and V2 is increased; when the applied pulse width needs to be increased, the phase difference between the double cutting plates V1 and V2 is reduced.

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