CN206061269U - 230MeV superconducting cyclotrons prevent the frame for movement of draw-out area harmful resonance - Google Patents
230MeV superconducting cyclotrons prevent the frame for movement of draw-out area harmful resonance Download PDFInfo
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- CN206061269U CN206061269U CN201621059741.8U CN201621059741U CN206061269U CN 206061269 U CN206061269 U CN 206061269U CN 201621059741 U CN201621059741 U CN 201621059741U CN 206061269 U CN206061269 U CN 206061269U
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- 239000000463 material Substances 0.000 claims abstract description 15
- 238000000605 extraction Methods 0.000 claims description 22
- 239000004020 conductor Substances 0.000 claims description 15
- 238000012545 processing Methods 0.000 claims description 8
- 239000000696 magnetic material Substances 0.000 abstract description 5
- 230000035699 permeability Effects 0.000 abstract 3
- 235000011888 snacks Nutrition 0.000 abstract 3
- 206010030899 opisthotonus Diseases 0.000 abstract 1
- 238000013461 design Methods 0.000 description 5
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
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Abstract
This utility model is related to a kind of 230MeV superconducting cyclotrons prevents the frame for movement of draw-out area harmful resonance, the magnetic pole of the structure is in double-decker, lower floor is magnetic pole root, upper strata is to have a snack plate with the permeability magnetic material of magnetic pole root same material, described permeability magnetic material has a snack the surface that plate is fixed on lower floor's magnetic pole root, and upper strata permeability magnetic material has a snack the protrusion side profile of plate compared with the protrusion side profile of lower floor's magnetic pole root with bigger opisthotonos angle.This utility model reduces axial resonance frequency ν before leading point under conditions of magnetic pole radius is not increasedz, it is to avoid ν is passed through before leading pointz=1 resonance, prevents the educt beaming flow axial direction quality variation caused by the resonance, reduces the beam loss of draw-out area, and then reduce the irradiation dose suffered by accelerator attendant.
Description
Technical Field
The utility model belongs to cyclotron design technology, concretely relates to 230MeV superconductive cyclotron prevents the mechanical structure of the harmful resonance in extraction area.
Background
According to the isochronism principle of cyclotrons, there are
In the formula, BcenterIs the central magnetic field, c is the speed of light, ω0The particle cyclotron frequency and r are the cyclotron radius. Given magnetic field and cyclotron frequency Bcenter、ω0The theoretical isochronous field can be given by equation (1). The cyclotron isochronous magnetic field increases with radius according to equation (1).
The free-running frequency of the isochronous cyclotron is approximated by the expression:
wherein the degree of modulation F is determined by the following formula:
wherein,<B>＝α·Bhill+(1-α)·Bvalley(5)
α is the proportion of the magnetic pole, Bhill、BvalleyThe magnetic fields of the peak and valley regions, respectively, of the central plane, in general Bhill>Bvalley。<B>Is the average magnetic field at radius r. In order to avoidThe beam loss caused by resonance is that the blade number N of the magnetic pole is more than or equal to 4 for the intermediate-energy cyclotron for extracting 230MeV proton, so the formula (3) is approximate to the formula (6):
in the formula
When the mean magnetic field of the cyclotron is not increased any more, as shown in formula (7)Namely, it isThe magnetic rigidity nearby is maximum, and v is obtained by being brought into the formula (6)rThe magnetic rigidity is maximum near 1, namely vrThe magnetic rigidity near 1 resonance represents the maximum acceleration energy of the cyclotron, and the isochronous cyclotron is usually selected to be vrAfter a radius of 1, the magnetic field is guided out in order to make full use of the guidance field. At this time, since the average magnetic field of the cyclotron starts to decrease after the radius increases to the peak value, the magnetic field at the extraction point is already in the region where the average magnetic field decreases with the radius. As can be seen from equation (7), n is near the extraction point>0, and n rapidly increases as the average magnetic field decreasing speed becomes higher. As can be seen from the formula (2), v is possibly crossed before the point of extractionzResonance of 1. Crossing v before exit pointzThe 1 resonance causes the axial beam quality to deteriorate.
In order to reduce the front axial resonance frequency v of the extraction pointzAccording to the formula (2), the field drop index n in the small region before the leading-out point needs to be reduced, the modulation degree F in the small region before the leading-out point needs to be reduced, or the spiral angle ξ in the small region before the leading-out point needs to be reduced, but the reduction of the field drop index n means that the radius of a magnetic pole is increased, the design of a leading-out system is difficult, the leading-out voltage is too high, the modulation degree F in the small region is changed very slowly and cannot meet the requirement of local reduction, and the reduction of the spiral angle ξ in the small region before the leading-out point structurally has difficulty.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to solve the problem that exists among the prior art, provide a 230MeV superconductive cyclotron and prevent to draw out the mechanical structure of district harmful resonance, under the condition that does not increase magnetic pole radius (do not influence and draw out the system design), reduce and draw out axial resonance frequency v before the pointzAvoid crossing v before leading-out pointzResonance of 1.
The technical scheme of the utility model as follows: the utility model provides a 230MeV superconductive cyclotron prevents mechanical structure of induction zone harmful resonance, the magnetic pole is bilayer structure, and the lower floor is the magnetic pole root, and the upper strata is the magnetic conduction material shimming board with the magnetic pole root with the material, magnetic conduction material shimming board fix the surface at lower floor's magnetic pole root, the protruding side profile of upper strata magnetic conduction material shimming board compares with the protruding side profile at lower floor's magnetic pole root and has bigger reverse dog-ear.
Further, the 230MeV superconducting cyclotron as described above prevents the mechanical structure of the extraction region from unwanted resonance, wherein the thickness of the shim plate of magnetically conductive material is smaller than the height of the root of the magnetic pole.
Further, the 230MeV superconducting cyclotron as described above has a mechanical structure for preventing unwanted resonance in the extraction region, wherein the magnetic conductive material shim plate is fixed to the surface of the root of the lower magnetic pole by means of bolts.
Further, the 230MeV superconducting cyclotron as described above prevents the mechanical structure of the extraction region from the unwanted resonance, wherein the shape and size of the magnetically conductive material shim plate provided on the root of each magnetic pole are the same for a cyclotron having a plurality of magnetic poles.
Further, the 230MeV superconducting cyclotron as described above has a mechanical structure for preventing unwanted resonance in the extraction region, wherein the magnetic field in the extraction region is locally fine-tuned by processing the outer surface profile of the padding plate of magnetically conducting material, thereby improving the resonance of the beam in the extraction region.
The utility model has the advantages as follows: adopt this practicalityAccording to the novel scheme, when the magnetic field of the cyclotron is measured and padded, the magnetic field of the lead-out area can be locally and finely adjusted by machining the side profile of the magnetic conducting material padding plate, and the resonance of beam current in the lead-out area is improved. The utility model discloses under the condition that does not increase magnetic pole radius (do not influence and draw system design), reduce and draw forth axial resonance frequency v before the pointzAvoid crossing v before leading-out pointzThe resonance of 1 prevents the deterioration of the axial quality of the extracted beam caused by the resonance, reduces the beam loss of the extraction area and further reduces the irradiation dose received by the accelerator maintenance personnel.
Drawings
FIG. 1 is a schematic diagram of a 230MeV superconducting cyclotron;
FIG. 2 is a side view of a pole structure of a 230MeV superconducting cyclotron to prevent unwanted resonance in the extraction region;
FIG. 3 is a top view of a magnetic pole structure of a 230MeV superconducting cyclotron to prevent unwanted resonance in the extraction region;
fig. 4 is a schematic diagram of the result of the magnetic field and particle tracking calculation after the magnetic pole is shimmed by adopting the structure of the present invention.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and examples.
The structure of the 230MeV superconducting cyclotron is shown in fig. 1, where 1 is a magnetic pole and is spiral, which is well known in the art. The utility model provides a 230MeV superconductive cyclotron prevents the magnetic pole structure of the harmful resonance in extraction area, the magnetic pole designs into bilayer structure, as shown in FIG. 2, the lower floor is magnetic pole root 2 (the main part of magnetic pole promptly), the upper strata be with magnetic conductive material shimming board 3 of magnetic pole root 2 with the material, magnetic conductive material shimming board 3 pass through the bolt fastening on the surface of magnetic pole root 2 of lower floor, magnetic conductive material shimming board 2's thickness H1 is less than magnetic pole root 3's high H2 far away.
The convex side profile of the lower magnetic pole root is in smooth transition in the leading-out area, and the processing is easy. Because the thickness H1 of magnetic conduction material shimming board 2 is less than the height H2 of magnetic pole root 3 far away, more convenient processing, consequently, the protruding side profile of upper strata magnetic conduction material shimming board can process bigger reverse dog-ear with the protruding side profile of lower floor's magnetic pole root for avoid the harmful resonance of extraction area, as shown in fig. 3, 4 is the profile of lower floor's magnetic pole root protruding side in the picture, and 5 is the profile of upper strata magnetic conduction material shimming board protruding side in the picture. Through processing alone upper layer magnetic material shimming board, form bigger reverse dog-ear in protrusion side profile department, then pass through the bolt with upper layer magnetic material shimming board and the surface coordination installation of lower floor's magnetic pole root, just so avoided carrying out the degree of difficulty of processing to whole magnetic pole. And when the magnetic field of the cyclotron is measured and compensated, the magnetic field of the lead-out area can be locally and finely adjusted by machining the outer surface profile of the magnetic conduction material compensation plate 2, and the resonance of the beam current in the lead-out area is improved.
For a cyclotron having a plurality of magnetic poles, the shape and size of the magnetically conductive material shim plate provided on the root of each magnetic pole are the same. The magnetic field of the lead-out region can be adjusted by processing the size of the reverse bend angle of the convex side profile of the magnetic conducting material shim plate.
Examples
Take a certain intermediate energy superconducting cyclotron as an example. The accelerator has four magnetic pole blades, and the radius R of the magnetic pole is 860 mm. According to the magnetic field calculation, in order to avoid passing through v before leading out a pointzAt a resonance of 1, a reverse bend angle occurs from a pole radius r of 810 mm. The root of the lower magnetic pole starts from the radius r of the magnetic pole which is 770mm, the contour of the side where the magnetic pole protrudes smoothly transits to facilitate processing, and the upper magnetic conducting material padding plate (with the thickness H1 which is 50mm) starts to process a large reverse folding angle from the radius r of the magnetic pole which is 770mm, wherein the reverse folding angle is about 110 degrees and is used for adjusting the magnetic field of the leading-out area and avoiding harmful resonance. Figure 4 meterThe calculation result shows that the size of the shim plate made of the magnetic conductive material can ensure that v is larger than v before the leading-out areaz<1, avoid vz1.
It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is also intended to encompass such modifications and variations.
Claims (5)
1. A mechanical structure of a 230MeV superconducting cyclotron for preventing unwanted resonance in the extraction region, comprising: the magnetic pole is bilayer structure, and the lower floor is the magnetic pole root, and the upper strata is the magnetic conduction material shimming board with the same material of magnetic pole root, the magnetic conduction material shimming board fix the surface at lower floor's magnetic pole root, the salient side profile of upper magnetic conduction material shimming board compares with the salient side profile of lower floor's magnetic pole root has bigger reverse dog-ear.
2. The mechanical structure of a 230MeV superconducting cyclotron of claim 1 for preventing unwanted resonance in the extraction region, wherein: the thickness of the magnetic conductive material shim plate is smaller than the height of the root of the magnetic pole.
3. The mechanical structure of a 230MeV superconducting cyclotron as claimed in claim 1 or 2 for preventing unwanted resonance in the extraction region, wherein: and the magnetic conductive material shimming plate is fixed on the surface of the root part of the lower-layer magnetic pole through a bolt.
4. The mechanical structure of a 230MeV superconducting cyclotron as claimed in claim 1 or 2 for preventing unwanted resonance in the extraction region, wherein: for a cyclotron having a plurality of magnetic poles, the shape and size of the magnetically conductive material shim plate provided on the root of each magnetic pole are the same.
5. The mechanical structure of a 230MeV superconducting cyclotron as claimed in claim 1 or 2 for preventing unwanted resonance in the extraction region, wherein: the magnetic field of the lead-out area is locally and finely adjusted by processing the outer surface profile of the magnetic conduction material padding plate, and the resonance of the beam current in the lead-out area is improved.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2016208182568 | 2016-07-29 | ||
| CN201620818256 | 2016-07-29 |
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| CN206061269U true CN206061269U (en) | 2017-03-29 |
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| CN201621059741.8U Withdrawn - After Issue CN206061269U (en) | 2016-07-29 | 2016-09-18 | 230MeV superconducting cyclotrons prevent the frame for movement of draw-out area harmful resonance |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106211540A (en) * | 2016-07-29 | 2016-12-07 | 中国原子能科学研究院 | 230MeV superconducting cyclotron prevents the frame for movement of draw-out area harmful resonance |
| CN107466152A (en) * | 2017-07-25 | 2017-12-12 | 中国科学院高能物理研究所 | Multipole magnet and its magnetic field harmonics shimming method |
| EP3876679A1 (en) * | 2020-03-06 | 2021-09-08 | Ion Beam Applications | Synchrocyclotron for extracting beams of various energies |
-
2016
- 2016-09-18 CN CN201621059741.8U patent/CN206061269U/en not_active Withdrawn - After Issue
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106211540A (en) * | 2016-07-29 | 2016-12-07 | 中国原子能科学研究院 | 230MeV superconducting cyclotron prevents the frame for movement of draw-out area harmful resonance |
| CN107466152A (en) * | 2017-07-25 | 2017-12-12 | 中国科学院高能物理研究所 | Multipole magnet and its magnetic field harmonics shimming method |
| CN107466152B (en) * | 2017-07-25 | 2019-09-20 | 中国科学院高能物理研究所 | Multipole magnet and its magnetic field harmonics shimming method |
| EP3876679A1 (en) * | 2020-03-06 | 2021-09-08 | Ion Beam Applications | Synchrocyclotron for extracting beams of various energies |
| US11160159B2 (en) | 2020-03-06 | 2021-10-26 | Ion Beam Applications S.A. | Synchrocyclotron for extracting beams of various energies |
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Granted publication date: 20170329 Effective date of abandoning: 20181009 |