Method for adjusting first harmonic of cyclotron

Abstract

The invention discloses a cyclotron first harmonic adjusting method, a magnet of a cyclotron is provided with a plurality of threaded holes, and each threaded hole is internally in threaded fit with an adjusting cock. The first harmonic adjusting method comprises the following steps: S1, calculating the adjusting amplitude of each adjusting cock according to the target amplitude and the target phase of the required first harmonic and the inherent phase of the adjusting cock; s2, the adjusting amount of each adjusting cock is calculated according to the adjusting amplitude of each adjusting cock; s3, the adjusting angle of each adjusting cock is calculated according to the adjusting amount of each adjusting cock; and S4, adjusting each adjusting cock according to the adjusting angle of each adjusting cock. The cyclotron first harmonic adjusting method has the advantages of being high in adjusting efficiency, low in adjusting cost, accurate in adjusting and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of medical cyclotron accelerators, and in particular to a method for regulating the first harmonic of a cyclotron accelerator. Background Art

[0002] The magnetic field in the midplane of a medical cyclotron accelerator affects the trajectory of the charged particle beam. During the beam tuning phase, the path of the beam movement needs to be adjusted by adjusting the magnetic field in the midplane. The first harmonic of the magnetic field is an important parameter that affects the accelerator's magnetic field.

[0003] The first harmonic adjustment method of the cyclotron in the related art uses shimming on the magnet to produce the first harmonic, which requires adding magnetic material or cutting on the pole, and often requires multiple adjustments, resulting in a large number of shimming operations, which consumes time and processing costs. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a cyclotron first harmonic regulation method, which has the advantages of high regulation efficiency, low regulation cost, and precise regulation.

[0005] To achieve the above object, a method for adjusting the first harmonic of a cyclotron is provided according to an embodiment of the present invention. A plurality of threaded holes are provided on the magnet of the cyclotron, and an adjusting cock is matched with the inner thread of each threaded hole. The method for adjusting the first harmonic includes the following steps:

[0006] S1. Calculate the adjustment amplitude of each of the adjusting cocks according to the target amplitude and target phase of the required first harmonic and the inherent phase of the adjusting cock;

[0007] S2, calculating the adjustment amount of each adjusting cock according to the adjustment amplitude of each adjusting cock;

[0008] S3, calculating the adjustment angle of each adjusting cock according to the adjustment amount of each adjusting cock;

[0009] S4. Adjust each of the adjusting cocks according to the adjustment angle of each of the adjusting cocks.

[0010] The cyclotron first harmonic regulation method according to the embodiment of the present invention has the advantages of high regulation efficiency, low regulation cost, and precise regulation.

[0011] In addition, the cyclotron first harmonic adjustment method according to the above embodiment of the present invention may also have the following additional technical features:

[0012] According to one embodiment of the present invention, there are four adjusting cocks including a first cock, a second cock, a third cock and a fourth cock.

[0013] According to one embodiment of the present invention, in step S1, assuming that the target amplitude is AM, the target phase is PH, the inherent phase of the first cock is PH1, the inherent phase of the second cock is PH2, the adjustment amplitude of the first cock is AM1, the adjustment amplitude of the second cock is AM2, the adjustment amplitude of the third cock is AM3, and the adjustment amplitude of the fourth cock is AM4, then:

[0014] AM1=AM×sin(PH-PH2) / sin(PH1-PH2);

[0015] AM2=AM×sin(PH1-PH) / sin(PH1-PH2);

[0016] AM3=-AM×sin(PH-PH2) / sin(PH1-PH2);

[0017] AM4=-AM×sin(PH1-PH) / sin(PH1-PH2).

[0018] According to one embodiment of the present invention, in step S2, it includes: obtaining the correspondence between the adjustment amplitude of the adjusting cock and the adjustment amount of the adjusting cock; and calculating the adjustment amount of each adjusting cock according to the adjustment amplitude of each adjusting cock and the correspondence.

[0019] According to one embodiment of the present invention, in step S3, assuming that the rotation angle of the first cock is AN1, the rotation angle of the second cock is AN2, the rotation angle of the third cock is AN3, the rotation angle of the fourth cock is AN4, the pitch of each adjusting cock is PI, the adjustment amount of the first cock is AD1, the adjustment amount of the second cock is AD2, the adjustment amount of the third cock is AD3, and the adjustment amount of the fourth cock is AD4, then:

[0020] AN1=AD1 / PI×360;

[0021] AN2=AD2 / PI×360;

[0022] AN3=AD3 / PI×360;

[0023] AN4=AD4 / PI×360.

[0024] According to one embodiment of the present invention, the pitch PI of each adjusting cock is 1-3 mm.

[0025] According to an embodiment of the present invention, the distances between the plurality of adjusting cocks and the central axis of the magnet are equal.

[0026] According to one embodiment of the present invention, a plurality of the adjusting cocks are arranged at equal intervals along the circumference of the magnet.

[0027] According to one embodiment of the present invention, the diameter of each adjusting cock is 12-20 mm.

[0028] According to one embodiment of the present invention, the magnet of the cyclotron includes a magnetic pole and an iron yoke, and the threaded hole is provided on the magnetic pole.

[0029] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0031] Figure 1 Schematic diagram of the structure of a cyclotron according to a cyclotron first harmonic regulation method according to an embodiment of the present invention.

[0032] Figure 2 It is a schematic diagram of the corresponding relationship between the adjustment amount and the adjustment amplitude of the adjustment cock in the cyclotron first harmonic adjustment method according to an embodiment of the present invention.

[0033] Figure 3 Schematic diagram of full-phase first harmonic amplitude of a cyclotron first harmonic adjustment method according to an embodiment of the present invention.

[0034] Figure 4 is a flow chart of a cyclotron first harmonic adjustment method according to an embodiment of the present invention.

[0035] Reference numerals: cyclotron 1 , iron yoke 11 , magnetic pole 12 , regulating cock 20 . DETAILED DESCRIPTION

[0036] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] The following describes a cyclotron first harmonic adjustment method according to an embodiment of the present invention with reference to the accompanying drawings.

[0040] like Figure 1-Figure 4 As shown, a plurality of threaded holes are provided on the magnet of the cyclotron 1, and each of the threaded holes is threadedly matched with an adjusting cock 20. Specifically, the adjusting cock 20 can be a soft magnetic part.

[0041] The primary harmonic regulation method comprises the following steps:

[0042] S1. Calculate the adjustment amplitude of each adjusting cock 20 according to the target amplitude and target phase of the required first harmonic and the inherent phase of the adjusting cock 20;

[0043] S2, calculating the adjustment amount of each adjusting cock 20 according to the adjustment amplitude of each adjusting cock 20;

[0044] S3, calculating the adjustment angle of each adjusting cock 20 according to the adjustment amount of each adjusting cock 20;

[0045] S4. Adjust each adjusting cock 20 according to the adjustment angle of each adjusting cock 20.

[0046] Specifically, by the threaded fit between the adjusting cock 20 and the threaded hole, the rotation of the adjusting cock 20 can be converted into the axial movement of the adjusting cock 20 relative to the threaded hole, and the relationship between the axial movement distance and the rotation angle of the adjusting cock 20 is related to the thread pitch of the adjusting cock 20, so that the axial movement distance of the adjusting cock 20 can be controlled by controlling the rotation angle of the adjusting cock 20 according to the thread pitch of the adjusting cock 20. For example, when the thread pitch of the adjusting cock 20 is 2 mm, screwing the adjusting cock 20 in 360 degrees can move the axial position of the adjusting cock 20 inward by 2 mm, and screwing the adjusting cock 20 out 360 degrees can move the axial position of the adjusting cock 20 outward by 2 mm.

[0047] Therefore, the magnitude of the magnetic field can be adjusted by changing the axial position of the adjusting cock 20 , and the first harmonic of the magnetic field with different phases and amplitudes can be obtained by adjusting the axial positions of multiple adjusting cocks 20 respectively.

[0048] The first harmonic of the magnetic field consists of two parameters, namely amplitude and phase.

[0049] In step S1, the adjustment amplitude of each adjusting cock 20 can be calculated according to the target amplitude and target phase of the required first harmonic and the inherent phase of the adjusting cock 20. It should be understood here that the inherent phase of the adjusting cock 20 is its own inherent parameter, which can be obtained by a person skilled in the art in a variety of ways.

[0050] In step S2, the adjustment amount of the adjusting cock 20 can be calculated according to the corresponding relationship between the adjustment amount and the adjustment amplitude of the adjusting cock 20 and the adjustment amplitude of the adjusting cock 20. It should be understood here that the adjustment amount of the adjusting cock 20 refers to its axial displacement. The relationship between the adjustment amount and the adjustment amplitude of the adjusting cock 20 can be known per se, for example, it has been determined during the design or installation process of the adjusting cock 20, or it can be obtained immediately during the adjustment process by measurement or simulation calculation. For example, Figure 2 As shown, Figure 2 The schematic diagram shows the corresponding relationship between the adjustment amount and the adjustment amplitude of the adjustment cock 20 . The adjustment amount of each adjustment cock 20 can be obtained by interpolating the adjustment amplitude of each adjustment cock 20 in the corresponding relationship.

[0051] In step S3 , the required adjustment angle of each adjusting cock 20 can be calculated according to the pitch of the adjusting cock 20 and the adjustment amount of each adjusting cock 20 .

[0052] In step S4, according to the calculated adjustment angle of each adjustment cock 20, the corresponding adjustment cock 20 is rotated to move the adjustment cock 20 axially by the required adjustment amount to achieve the corresponding adjustment amplitude change, so that the first harmonic reaches the target amplitude and target phase.

[0053] After adjusting the first harmonic to the target amplitude and target phase, beam adjustment can be performed. If the adjusted amplitude and phase do not meet the beam adjustment requirements, the first harmonic can be adjusted to a new target amplitude and target phase, and then beam adjustment can be performed again, and the cycle is repeated until the required amplitude and phase are obtained.

[0054] According to the cyclotron first harmonic adjustment method of the embodiment of the present invention, by setting a plurality of threaded holes on the magnet of the cyclotron 1, and fitting the adjusting cock 20 with the thread in each threaded hole, the axial position of the adjusting cock 20 can be adjusted by rotating the adjusting cock 20. Thus, the magnitude of the magnetic field can be adjusted by changing the axial position of the adjusting cock 20, and the first harmonics of the magnetic field with different phases and amplitudes can be obtained by adjusting the axial positions of the plurality of adjusting cocks 20 respectively. Compared with the method of adjusting by shimming processing in the related art, the adjusting cock 20 can be adjusted repeatedly for multiple times, and it is not necessary to repeatedly perform shimming processing of magnetic materials, which can save a large number of shimming processing operations, improve the adjustment efficiency, save the adjustment time, and save the processing cost.

[0055] Furthermore, by means of the threaded fit between the adjusting plug 20 and the threaded hole, the axial displacement of the adjusting plug 20 can be precisely related to its rotation angle, so that the axial position of the adjusting plug 20 can be precisely adjusted by rotating the adjusting plug 20, thereby precisely controlling the adjustment amount and adjustment amplitude of the adjusting plug 20, and realizing precise adjustment of the amplitude and phase of the first harmonic. Therefore, according to the first harmonic adjustment method of the cyclotron according to the embodiment of the present invention, the adjustment amplitude of the adjusting plug 20 can be calculated by the target amplitude and target phase of the required first harmonic, and the adjustment amount and rotation angle of the adjusting plug 20 can be further calculated to realize precise adjustment of the first harmonic, obtain the first harmonic of the magnetic field with different phases and amplitudes, and further improve the adjustment efficiency.

[0056] Therefore, the cyclotron first harmonic regulation method according to the embodiment of the present invention has the advantages of high regulation efficiency, low regulation cost, and precise regulation.

[0057] The following describes a cyclotron first harmonic adjustment method according to a specific embodiment of the present invention with reference to the accompanying drawings.

[0058] Specifically, Figure 1As shown, there are four adjusting cocks 20, including a first cock, a second cock, a third cock and a fourth cock. In this way, the magnetic field magnitudes at four positions can be adjusted by using the four cocks, so as to obtain magnetic field first harmonics with different phases and amplitudes.

[0059] More specifically, in step S1, assuming that the target amplitude is AM (Amplitude), the target phase is PH (Phase), the inherent phase of the first cock is PH1, the inherent phase of the second cock is PH2, the adjustment amplitude of the first cock is AM1, the adjustment amplitude of the second cock is AM2, the adjustment amplitude of the third cock is AM3, and the adjustment amplitude of the fourth cock is AM4, then:

[0060] AM1=AM×sin(PH-PH2) / sin(PH1-PH2);

[0061] AM2=AM×sin(PH1-PH) / sin(PH1-PH2);

[0062] AM3=-AM×sin(PH-PH2) / sin(PH1-PH2);

[0063] AM4=-AM×sin(PH1-PH) / sin(PH1-PH2).

[0064] In this way, the target amplitude, the target phase, the inherent phase of the first cock and the inherent phase of the second cock can be put into the formula to obtain the adjustment amplitude of each adjustment cock 20.

[0065] Furthermore, in step S2, it includes:

[0066] Obtaining the corresponding relationship between the adjustment amplitude of the adjustment cock 20 and the adjustment amount of the adjustment cock 20;

[0067] The adjustment amount of each adjusting cock 20 is calculated according to the adjustment amplitude of each adjusting cock 20 and the corresponding relationship.

[0068] Specifically, “obtaining the corresponding relationship between the adjustment amplitude of the adjusting cock 20 and the adjustment amount of the adjusting cock 20 ” can be obtained by measurement or simulation calculation, and those skilled in the art can select the acquisition method according to actual needs. This makes it easy to calculate the adjustment amount of each adjusting cock 20 .

[0069] Furthermore, in step S3, assuming that the rotation angle of the first cock is AN1 (Angle), the rotation angle of the second cock is AN2, the rotation angle of the third cock is AN3, the rotation angle of the fourth cock is AN4, the pitch of each adjusting cock is PI (Pitch), the adjustment amount of the first cock is AD1 (Adjustment), the adjustment amount of the second cock is AD2, the adjustment amount of the third cock is AD3, and the adjustment amount of the fourth cock is AD4, then:

[0070] AN1=AD1 / PI×360;

[0071] AN2=AD2 / PI×360;

[0072] AN3=AD3 / PI×360;

[0073] AN4=AD4 / PI×360.

[0074] In this way, the rotation angle of the adjusting cock 20 can be calculated according to the pitch of the adjusting cock 20 and the adjustment amount of the adjusting cock 20 .

[0075] Optionally, the pitch PI of each adjusting cock 20 is 1-3 mm. Here, the pitch of the adjusting cock 20 is preferably 2 mm. Specifically, the adjustment error of the adjusting cock 20 can be controlled within plus or minus 0.05 mm, and the angle error is within plus or minus 9°, so that the axial position of the adjusting cock 20 can be adjusted by rotating the adjusting cock 20, thereby improving the adjustment accuracy.

[0076] Figure 1 The cyclotron of the cyclotron first harmonic adjustment method according to some examples of the present invention is shown. Figure 1 As shown, the distances between the multiple adjusting cocks 20 and the central axis of the magnet are equal, which can facilitate the adjustment of the first harmonic of the magnetic field.

[0077] Specifically, Figure 1 As shown, a plurality of adjusting cocks 20 are arranged at equal intervals along the circumference of the magnet. In other words, in the circumference of the magnet, the intervals between adjacent adjusting cocks 20 are 90 degrees. This facilitates the adjustment of the first harmonic of the magnetic field.

[0078] Optionally, the diameter of each adjusting cock 20 is 12-20 mm. Here, the diameter of the adjusting cock 20 is preferably 16 mm. Specifically, the adjusting cock 20 can adopt an M16 standard external thread. This can facilitate improving the adjustment accuracy of the adjusting cock 20 and reduce the error.

[0079] More specifically, the magnet of the cyclotron 1 includes an iron yoke 11 and a magnetic pole 12, and the threaded hole is provided on the magnetic pole 12. This makes it easier to adjust the first harmonic of the magnetic field.

[0080] Specifically, if Figure 3 As shown, according to the cyclotron first harmonic regulation method of the embodiment of the present invention, the maximum first harmonic amplitude can reach 40Gs according to the maximum regulation amount designed for the regulating cock 20, and the maximum first harmonic amplitude in all phases can reach 27Gs.

[0081] Other structures and operations of the cyclotron first harmonic regulation method according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0082] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0083] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A cyclotron first harmonic regulation method, characterized in that: The magnet of the cyclotron is provided with a plurality of threaded holes, each of which has an inner thread with an adjusting cock, and the first harmonic adjustment method comprises the following steps: S1. Calculate the adjustment amplitude of each of the adjusting cocks according to the target amplitude and target phase of the required first harmonic and the inherent phase of the adjusting cock; S2, calculating the adjustment amount of each adjusting cock according to the adjustment amplitude of each adjusting cock; S3, calculating the adjustment angle of each adjusting cock according to the adjustment amount of each adjusting cock; S4. Adjust each of the adjusting cocks according to the adjustment angle of each of the adjusting cocks.

2. The cyclotron first harmonic adjustment method according to claim 1, characterized in that: The number of the regulating cocks is four and they include a first cock, a second cock, a third cock and a fourth cock.

3. The cyclotron first harmonic adjustment method according to claim 2, characterized in that: In step S1, assuming that the target amplitude is AM, the target phase is PH, the inherent phase of the first cock is PH1, the inherent phase of the second cock is PH2, the adjustment amplitude of the first cock is AM1, the adjustment amplitude of the second cock is AM2, the adjustment amplitude of the third cock is AM3, and the adjustment amplitude of the fourth cock is AM4, then: AM1=AM×sin(PH-PH2) / sin(PH1-PH2); AM2=AM×sin(PH1-PH) / sin(PH1-PH2); AM3=-AM×sin(PH-PH2) / sin(PH1-PH2); AM4=-AM×sin(PH1-PH) / sin(PH1-PH2).

4. The cyclotron first harmonic regulation method according to claim 1, characterized in that: In step S2, it includes: Obtaining a corresponding relationship between an adjustment amplitude of the adjusting cock and an adjustment amount of the adjusting cock; The adjustment amount of each adjusting cock is calculated according to the adjustment amplitude of each adjusting cock and the corresponding relationship.

5. The cyclotron first harmonic regulation method according to claim 2, characterized in that: In step S3, assuming that the rotation angle of the first cock is AN1, the rotation angle of the second cock is AN2, the rotation angle of the third cock is AN3, the rotation angle of the fourth cock is AN4, the pitch of each adjusting cock is PI, the adjustment amount of the first cock is AD1, the adjustment amount of the second cock is AD2, the adjustment amount of the third cock is AD3, and the adjustment amount of the fourth cock is AD4, then: AN1=AD1 / PI×360; AN2=AD2 / PI×360; AN3=AD3 / PI×360; AN4=AD4 / PI×360.

6. The cyclotron first harmonic regulation method according to claim 5, characterized in that: The pitch PI of each regulating cock is 1-3 mm.

7. The cyclotron first harmonic regulation method according to claim 1, characterized in that: The distances between the plurality of adjusting cocks and the central axis of the magnet are equal.

8. The cyclotron first harmonic regulation method according to claim 1, characterized in that: The plurality of adjusting cocks are arranged at equal intervals along the circumference of the magnet.

9. The cyclotron first harmonic adjustment method according to claim 1, characterized in that: The diameter of each of the regulating cocks is 12-20 mm.

10. The cyclotron first harmonic adjustment method according to claim 1, characterized in that: The magnet of the cyclotron comprises a magnetic pole and an iron yoke, and the threaded hole is arranged on the magnetic pole.

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