CN205883693U - 230MeV superconducting cyclotron avoids drawing forth harmful resonant field structure in district - Google Patents

Abstract

The utility model relates to a 230MeV superconducting cyclotron avoids drawing forth harmful resonant field structure in district, breach in that magnetic pole protrusion side wheel wide department sets up the rounding off adopts the magnetic pole protrusion side breach position cooperation installation of seting up with the magnetic pole with the magnetic materials cushion of material, the internal surface of magnetic materials cushion and the protrusion side breach tight fit of magnetic pole, the outer surface profile's of magnetic materials cushion the front and back end and the protrusion side breach fore -and -after profile rounding off of magnetic pole to the required anti - dog -ear of the harmful resonance in district is avoided drawing forth in formation. The utility model discloses not increasing under the radial condition of magnetic pole, reducing and to draw some front axles to resonance frequency nu z, the resonance of avoiding passing through nu z=1 before drawing a little prevents to draw line axial quality variation by what this resonance led to the fact, reduces to draw the beam damage in district, and then reduces the radiation dose that accelerator maintainer received.

Description

230MeV superconducting cyclotron avoids the field structure of draw-out area harmful resonance

Technical field

This utility model belongs to cyclotron designing technique, is specifically related to a kind of 230MeV superconducting cyclotron and avoids The field structure of draw-out area harmful resonance.

Background technology

Isochronism principle according to cyclotron, has

$B_0\left(r\right)=B_{center}\mathrm{\γ}\left(r\right)=B_{center}\sqrt{\frac{c^2}{c^2-{\left({\mathrm{\ω}}_{0}r\right)}^2}}---\left(1\right)$

In formula, B_centerBeing central magnetic field, c is the light velocity, ω₀For particle cyclotron frequency, r is radius of gyration.To fixed-field with Cyclotron frequency B_center、ω₀, by formula (1) can be given theory etc. time field.According to formula (1), cyclotron isochronism magnetic Field is with increasing radii.

The free oscillation frequency approximate expression of isochronous cyclotron is:

$v_z^2=n+\frac{N^2}{N^2-1}\·F\·(1+2{\tan }^2\mathrm{\ξ})---\left(2\right)$

$v_r^2=1-n+\frac{3\·N^2}{(N^2-1)\·(N^2-4)}\·F\·(1+2{\tan }^2\mathrm{\ξ})---\left(3\right)$

In formula, modulation degree F is determined by following formula:

$F=1-\frac{<B^2>}{<B{>}^2}=\frac{\mathrm{\&alpha;}\&CenterDot;(1-\mathrm{\&alpha;})\&CenterDot;{(B_{hill}-B_{valley})}^2}{{(\mathrm{\&alpha;}\&CenterDot;B_{hill}+(1-\mathrm{\&alpha;})\&CenterDot;B_{valley})}^2}---\left(4\right)$

Wherein,<B>=α B_hill+(1-α)·B_valley (5)

α is the ratio shared by magnetic pole, B_hill、B_valleyIt is respectively the magnetic field in central plane superiors district and paddy district, typically comes Say, B_hill>B_valley.<B>it is the average magnetic field at radius r.In order to avoidThe beam loss that resonance causes, for drawing Go out the medium-energy cyclotron of 230MeV proton, number of blade N >=4 of magnetic pole, therefore (3) formula is approximately (6) formula:

$v_r^2=1-n---\left(6\right)$

In formula

Known by (7) formula, when cyclotron average magnetic field is not further added byI.e.Near Magnetic rigidity maximum, be brought in (6) formula and obtain ν_rNear=1, magnetic rigidity is maximum, i.e. ν_rThe magnetic rigidity of=1 near-resonance embodies The size of cyclotron maximum acceleration energy, usual isochronous cyclotron selects at ν_rDraw after=1 radius, with Just magnetic field pulse guide field is made full use of.At this moment, owing to cyclotron average magnetic field begins to decline with after increasing radii to peak value, draw The region that the magnetic field of point declines with radius already in average magnetic field.From (7) formula, n near leading point > 0, and along with flat All magnetic field decrease speeds accelerate, and n becomes rapidly big.From (2) formula, before leading point, likely pass through ν_zThe resonance of=1.Drawing ν is passed through before going out a little_zThe resonance of=1 can cause axial bundle stream quality variation.

In order to reduce axial resonance frequency ν before leading point_z, according to (2) formula, need to reduce the field in front zonule, leading point Landing index n；Or reduce modulation degree F in front zonule, leading point；Or reduce front zonule, leading point inner-spiral angle ξ.But Reducing field landing index n to mean to increase magnetic pole radius, can cause extraction system difficult design, extraction voltage is too high；The least In region, modulation degree F change slowly cannot meet the requirement that local diminishes；Reduce front zonule, leading point inner-spiral angle ξ, Magnetic pole can be caused to protrude side profile and occur opisthotonos angle drastically near draw-out area, directly processing is difficult to ensure that and processes draw-out area Required magnetic pole contour line.

Utility model content

The purpose of this utility model is for problems of the prior art, it is provided that a kind of 230MeV superconducting cyclotron adds The field structure of draw-out area harmful resonance avoided by speed device, in the condition not increasing magnetic pole radius (not affecting extraction system design) Under, reduce axial resonance frequency ν before leading point_z, it is to avoid before leading point, pass through ν_zThe resonance of=1.

The technical solution of the utility model is as follows: a kind of 230MeV superconducting cyclotron avoids draw-out area harmful resonance Field structure, protrudes the breach offering rounding off at side profile, employing and the magnetic pole permeability magnetic material cushion block with material at magnetic pole Protrude side gap position at the magnetic pole offered and coordinate installation；The inner surface of described permeability magnetic material cushion block lacks with the protrusion side of magnetic pole Tight-lipped cooperation；The round and smooth mistake of profile protruded before and after side breach of end and magnetic pole before and after the outer surface profile of permeability magnetic material cushion block Cross, and form the opisthotonos angle avoided needed for the harmful resonance of draw-out area.

Further, 230MeV superconducting cyclotron as above avoids the field structure of draw-out area harmful resonance, its In, for single magnetic pole, described permeability magnetic material cushion block is an integral single piece, or is divided into sliceable multiple accessories Combination.

Further, 230MeV superconducting cyclotron as above avoids the field structure of draw-out area harmful resonance, its In, described permeability magnetic material cushion block is connected by bolt is fixing with the protrusion side breach of magnetic pole.

Further, 230MeV superconducting cyclotron as above avoids the field structure of draw-out area harmful resonance, its In, for having the cyclotron of multiple magnetic pole, at the protrusion side profile of each magnetic pole, offer the breach of rounding off, The shape and size of the permeability magnetic material cushion block that breach is arranged are identical.

Further, 230MeV superconducting cyclotron as above avoids the field structure of draw-out area harmful resonance, its In, the magnetic field of draw-out area is fine-tuned by processing the appearance contour shape of described permeability magnetic material cushion block.

The beneficial effects of the utility model are as follows: use scheme of the present utility model, in the magnetic-field measurement of cyclotron With when having a snack, the magnetic field of local fine regulation draw-out area can be come by the outer surface profile of machining permeability magnetic material cushion block, keep away Exempt from the difficulty that whole magnetic pole is processed, improve the line resonance in draw-out area.This utility model is not increasing magnetic pole radius (not shadow Ring extraction system design) under conditions of, reduce axial resonance frequency ν before leading point_z, it is to avoid before leading point, pass through ν_z=1 be total to Shake, prevent the axial quality variation of educt beaming flow caused by this resonance, reduce the beam loss of draw-out area, and then reduce accelerator Irradiation dose suffered by attendant.

Accompanying drawing explanation

Fig. 1 is the structural representation of 230MeV superconducting cyclotron；

Fig. 2 is the field structure schematic diagram that 230MeV superconducting cyclotron avoids draw-out area harmful resonance；

Fig. 3 is to use structure of the present utility model to have a snack magnetic field and the result schematic diagram of Particle tracking calculating after magnetic pole.

Detailed description of the invention

With embodiment, this utility model is described in detail below in conjunction with the accompanying drawings.

The structure of 230MeV superconducting cyclotron is as it is shown in figure 1,5 be magnetic pole in figure, and twist, this is this area Known technology.As in figure 2 it is shown, the mode that this utility model uses magnetic pole to have a snack solves the problem that line resonates, institute in draw-out area The 230MeV superconducting cyclotron provided avoids the field structure of draw-out area harmful resonance as follows: protrude side profile at magnetic pole 1 Place offers rounding off and the breach 3 being easily worked, and uses the permeability magnetic material cushion block 2 of material as magnetic pole 1 to carry out magnetic pole Have a snack, by bolt 4, permeability magnetic material cushion block 2 is coordinated installation with the protrusion side breach 4 of magnetic pole 1.The interior table of permeability magnetic material cushion block 2 Face closely cooperates with the protrusion side breach 3 of magnetic pole 1；End and the protrusion of magnetic pole 1 before and after the outer surface profile of permeability magnetic material cushion block 2 Profile rounding off before and after side breach 3, and form the opisthotonos angle avoided needed for the harmful resonance of draw-out area.Permeability magnetic material cushion block 2 Can be designed as meeting the arbitrary shape of above-mentioned requirements, local can be come by the outer surface profile of machining permeability magnetic material cushion block The magnetic field of draw-out area is fine-tuned.

For single magnetic pole 1, permeability magnetic material cushion block 2 can be integral single piece；Sliceable multiple join can also be divided into The combination of part, the splicing of multiple accessories coordinates the protrusion side breach 4 being arranged on magnetic pole 1, and the cushion block entirety after combination should meet above-mentioned Closely cooperate and the structural requirement of rounding off with the side breach that protrudes of magnetic pole.

Generally, for having the cyclotron of multiple magnetic pole, offer at the protrusion side profile of each magnetic pole Rounding off and the breach being easily worked, the shape and size of the permeability magnetic material cushion block 2 of all magnetic poles should be consistent.

Embodiment

In certain as a example by energy superconducting cyclotron.This accelerator has four magnetic pole blades, magnetic pole radius R=860mm.Root According to magnetic field calculation, in order to avoid passing through ν before leading point_zThe resonance of=1, starts opisthotonos angle occur from magnetic pole radius r=810mm. From the beginning of magnetic pole radius r=770mm, magnetic pole protrudes the profile design machining gap of side, increases permeability magnetic material cushion block.Magnetic pole lacks At Kou, profile and the inner surface profile of permeability magnetic material cushion block that coordinates with it are circular arc, and arc radius R is 70mm, more than processing Tool radius (42mm) needed for magnetic pole, it is simple to processing；The opisthotonos angle θ of the outer surface profile of permeability magnetic material cushion block is 110 degree, warp Cross magnetic field and Particle tracking to calculate, Fig. 3 result of calculation show, use such magnetic pole indentation, there profile and coordinate with it Permeability magnetic material cushion block size, before going out draw-out area, can make ν_z< 1, it is to avoid ν_zThe harmful resonance of=1.

Obviously, those skilled in the art can carry out various change and modification without deviating from this practicality to this utility model Novel spirit and scope.So, if these amendments of the present utility model and modification are belonged to this utility model claim And within the scope of equivalent technology, then this utility model is also intended to comprise these change and modification.

Claims (5)

1. a 230MeV superconducting cyclotron avoids the field structure of draw-out area harmful resonance, it is characterised in that: at magnetic pole Protrude the breach (3) offering rounding off at side profile, employing and the magnetic pole permeability magnetic material cushion block (2) with material offered Magnetic pole protrudes breach (3) position, side and coordinates installation；The inner surface of described permeability magnetic material cushion block (2) and the protrusion side breach of magnetic pole (3) tight fit；Profile before and after end and protrusion side breach (3) of magnetic pole before and after the outer surface profile of permeability magnetic material cushion block (2) Rounding off, and form the opisthotonos angle avoided needed for the harmful resonance of draw-out area.

2. 230MeV superconducting cyclotron as claimed in claim 1 avoids the field structure of draw-out area harmful resonance, and it is special Levy and be: for single magnetic pole, described permeability magnetic material cushion block (2) is an integral single piece, or is divided into sliceable The combination of multiple accessories.

3. 230MeV superconducting cyclotron as claimed in claim 1 or 2 avoids the field structure of draw-out area harmful resonance, its It is characterised by: described permeability magnetic material cushion block (2) is connected by bolt (4) is fixing with protrusion side breach (3) of magnetic pole.

4. 230MeV superconducting cyclotron as claimed in claim 1 or 2 avoids the field structure of draw-out area harmful resonance, its It is characterised by: for having the cyclotron of multiple magnetic pole, at the protrusion side profile of each magnetic pole, offer rounding off Breach, the shape and size of permeability magnetic material cushion block that breach is arranged are identical.

5. 230MeV superconducting cyclotron as claimed in claim 1 or 2 avoids the field structure of draw-out area harmful resonance, its It is characterized by the appearance contour shape processing described permeability magnetic material cushion block so that the magnetic field of draw-out area is fine-tuned.