DE1244972B - Method for irradiating by means of corpuscular rays - Google Patents

Description

GERMAN

PATENT OFFICE

LEGAL LETTERING

German classes : 21g -21/01

Number: 1244 972 - ■■ ■

File number: V18107 VIII c / 21 _;

Filing date: February 23, 1960 *

Opened on: July 20, 1967

It is known to use a suitably homogeneous electron beam of high energy and matter to irradiate high intensity, for example for the purpose of sterilizing food, pharmaceuticals and the like, wherein the generated in a discharge tube by using electromagnetic means Corpuscular beam of substantially circular cross-section through the use of electrical Deflection means is converted into a bundle of rays strip-shaped cross-section, so that the medium to be irradiated in the form of a stripe with a perpendicular to the stripe axis of the bundle lying direction of movement is pulled past. This cross-sectional conversion of the corpuscular beam is associated with a deflection of about 90 ° in this known arrangement.

It is also used for mass spectroscopy purposes known, by deflection in a magnetic field directed perpendicular to the direction of movement to focus ions of different speeds emanating from an elongated ion source, so that ions of the same velocity emanating from the ion source at a certain point be focused and the ions of other velocity appear focused in another point. In this known arrangement, the deflecting field thus has a speed-sorting effect.

It is also well known in the oscilloscope art to pass a cathode ray through a magnetic Deflect alternating field over a surface.

The invention aims at the elementary particles generated in the accelerator tube from charged elementary particles same rest mass, but with different speed existing corpuscular beam with Speed sorting to pull apart to a beam of strip-shaped cross-section and the to periodically swing the beam formed in this way back and forth over an object surface to be irradiated, see above that the irradiated strip-shaped surface of an object is swept over by rays, which in the transverse direction of the strip have different energies.

A method for irradiating by means of a corpuscular beam of charged particles of the same rest mass, in which a practically parallel beam of preferably circular cross-section in a magnetic field whose lines of force are perpendicular to the beam axis, directed by deflection by 90 ° onto the surface to be irradiated and here in a Beam is reshaped strip-shaped cross-section, is characterized according to the invention in that the irradiation method, which is randomly distributed over the cross-section in the original beam, is carried out by means of
Corpuscular rays

Applicant:

Varian Associates, Palo Alto, Calif. (V. St. A.)

Representative:

Dr. phil. G. B. Hagen, patent attorney,

Munich-Solln, Franz-Hals-Str. 21

Named as inventor:

Craig Spencer, Palo Alto, Calif. (V. St. A.)

Claimed priority:

V. St. v. America March 9 , 1959 (798 064)

Particles of different velocities are spatially separated from each other by the magnetic field and are focused in different focal points that after passing through the magnetic field the Surface elements in the .strip longitudinal direction of particles of different speeds and in the Stripe transverse direction of particles are formed essentially at the same speed and that periodically the entire strip-shaped beam by a second magnetic field in the transverse direction of the strip is deflected and pivoted over the surface to be irradiated.

In order to ensure the desired stripe-shaped oscillation of the object to be irradiated by the beams, the second magnetic field supplying the periodic deflection field is expediently designed in such a way that it generates such a gradient in the magnetic field that the particles of higher speed of the beam are deflected through parts of the deflection field, in which the gradient of the magnetic flux is greater than on the particles through which the lower velocity particles are directed. '

To find the appropriate distraction ratios in the first one intended for speed separation Ensure magnetic field is according to a further embodiment of the invention on the entry side of the Field between the pole pieces provided for generating the same, each a rotatable, made of magnetic Material provided for existing segment. It can this magnetic field arrangement to a

709 617/392

3 4

The other end of the tube 14, which is perpendicular to the plane of the particle trajectories, has a round vacuum

Axis be rotatable. tight window 19, and the side of the junction

Before the particles enter the line 15, which connects to the coupling of the pipe 14

The magnetic field causing the speed separation is applied in a gradual transition

if they pass through one of the connection points attached to the pipe 14 from FIG. 5, so

four magnetic poles existing focussing magnet - that the cathode ray 11, which the tube 14 through-

ten that holds the particles together axially. sets, steered down through the junction 15

Other properties and uses of the will. To prevent damage from radiation-invention result from the following statement, the parts of the chamber 13 which are from Spelling and the drawings. From the figures io scattered electrons are shown with aluminum clothes that are cooled by a liquid.

F i g. 1 is a perspective view of a line for focusing, a four-pole magnet 21 is coaxial

aren electron accelerator, the deflection arranged around the tube 14 in the acceleration

device is shown partially broken and niger stage 12, so that in the tube 14 a focus-

Trajectories of electrons slightly different 15 of the magnetic field is generated. One in the drawing

Energy are shown, not shown supplies power supply device

F i g. 2 shows a cross-sectional representation in enlarged direct current on the focusing magnet 21, around the tem scale, with the electron distribution in the cathode beam horizontally or vertically to focus beam within the accelerator part of FIG. 1 ren and thereby the cross-section of the electron accordingly the section line 2-2 is reproduced to set 20 beam that emerges from the deflection device.

F i g. 3 is an enlarged cross-sectional view of the step.

in Fig. 1 arrangement shown, the elec- A deflection magnet 22 with vertical pole faces

tronenbahnen are reproduced and the representation lies on both sides of the cathode ray 11 outside

Development of the section line 3-3 of FIG. 1 corresponds to the chamber 13, where the junction 15 on the pipe 14

F i g. 4 shows a cross-sectional view of the arrangement 25, so that the cathode ray 11 is bent by 90 ° according to FIG. 3, the electron trajectories being steered. The deflecting magnet 22 is shown with the same and the line of intersection in FIG. 3 with 4-4 energized electromagnet and has two pole marks is, pieces on a yoke 23, namely a north pole 24

F i g. 5 is a perspective view of the lower one with a winding 25 and a south pole 26 with one

Part of the deflecting magnet, with two possible 30 windings 27. The deflecting magnet 22 is thereby

borrowed positions of the exit surface of the magnet that energized that current the windings 25 and 27 of

a magnetic force acting on a charge carrier is supplied to a current source (not shown),

lines are shown, wherein the power source is designed so that the

F i g. 6 shows a cross section through the in FIG. 3 dar- current strength can be adjusted. The top employee Arrangement, wherein the electrons shown 35 step surface 28 of the deflecting magnet 22 is around a are that penetrate the cross-section; for F i g. 6 Angle of about 3Ό ° with respect to the horizontal relevant cutting line is in F i g. 3 inclined at 6-6 direction, and a lower exit surface 29 is inclined by about 45 ° to the horizontal direction.

F i g. 6 A is a modification of the one shown in FIG. 6 shown when the deflection magnet 22 is not put into operation Magnet arrangement, 40 is set, the cathode ray 11 runs in a straight line

F i g. 7 shows a cross section through a further extension through the tube 14 and penetrated

embodiment of the invention, the round window 19; when the deflection magnet 22

F i g. 8 shows a cross section corresponding to the cutting excitation, the electron beam 11 is about a

line 8-8 of FIG. 7. Angle of about 90 ° steered down by the

The effect of the magnetic field between the pole deflection devices, which will be discussed below is designed in such a way that they have elec- tric shoes 24 and 26; it then runs the cathode trons diverts and then distracts. But you can beam through junction 15. A cathode ray also for other deflecting and deflecting devices from an average electron energy of about can be used, for example, for rays from 12 MeV being turned by 90 ° through the deflecting magnet 22 Protons exist. The device can be redirected at 50 when the field strength is around 3500 Gauss. Direct current operation of the beam as well as with impulse electrons, the energy of which is greater than the continuous operation of the beam can be used. Cutting energy of the cathode ray 11, place between

A cathode ray 11 emerges from an acceleration see the magnetic poles 24 and 26 a larger one

gerstufe 12 of a linear accelerator and way back as electrons of lower energy before

is guided horizontally into an evacuated chamber 13, a deflection of 90 ° has taken place. For this reason

tet, which includes a horizontal pipe 14; the cam is the lower exit surface 29 of the deflection magnet

mer is further through a rectangular branching off th 22 approximately at 45 ° with respect to the horizontal

Tube 15 is formed, which is directed downward, and inclined direction, so that electrons of greater energy

a funnel part 16 attaches itself to this tube, a correspondingly greater path length between the

which through an elongated vacuum-tight window 17 have 60 poles 24 and 26 and all electrons from the

at its end is complete. The funnel-shaped field of the deflecting magnet 22 emerge in parallel,

Deflector 16 is in a horizontal cross-section after it has previously been deflected by 90 °,

rectangular, with the long side of the rectangle A rotatable semicircular piece 32 made from

is perpendicular to the longitudinal axis of the tube 14. The magnetic material is on the input side of a

Tube 14 is aligned with accelerator stage 12- 65 of each pole 24 and 26 between windings and

tet and provided with the same by a rotary coupling 18 the pole faces of the deflection magnet 22,

connected which a rotation of the chamber 13 about and each rotatable piece 32 has a flat outer

the axis of the electron beam 11 is allowed. The page 28, which, as F i g. 3 shows the entry

5 6

surface 28 forms. These semicircular pieces of deflected cathode ray 37 are adjacent. The poles by means of a handle 33, which is simultaneously on both surfaces 41 and 44 of the deflection magnet 38 are hy-pieces 32 attacks, to be rotated; it can have the perbolic vertical surfaces so that all electrons Order but can also be made so that only one of a cathode ray, the different energy be-magnetic piece is rotated by a handle in each case. 5 sit, ab-es at essentially the same angle the entry surface 28 of the deflecting magnet can be deflected. Electricity is generated from a power source 22 fed at any angle with respect to windings 42 and 45, so that a magne-horizontal direction by adjusting the rotatable table field in the chamber 13 between the pole pieces 32 can be set so that the surfaces 41 and 44 result. For the purpose of The size of the irradiating electron flow resulting from the connection of the cathode ray tubes are in the past Deflector exiting, set to see a particular waveform of a voltage can. It can instead also produce replaceable and the control electrode of a triode or Pieces, each of which has a flat lead corresponding to a transistor amplifier, for the purpose of has inclined entry surface, instead of the rotatable one to control the current flowing from the power source Pieces 32 are used to attach a given 15 to the deflection windings 42 and 45 of the magnet Ensure the angle of inclination of the entry surface 28. 38 is delivered; this way the amplitude

The magnetic field strength of the deflecting magnet and the direction of the magnetic field between

22 is set so that an electron of the beam 11, the pole faces 41 and 44 depending on the

which has medium energy, controlled an orbit 24 between time. If the polarity of the pole pieces of the

describes the poles of the deflecting magnet 22 and ao deflecting magnet 38 is reversed, the reversed

from the deflecting magnet in the chamber 13 undirected cathode beam moves back and forth in the

deflecting device 16 moves out at the center of the inclined exit surface 29.

occurs. In such circumstances, an electron, Da, obeys the pole faces 41 and 44 of the deflecting magnet which is curved 20% less than the average energy 38, then the side of the deflected lies the electrons of the beam 11 has a path 35, 25 cathode ray 37, which carries higher energy, which is shorter than the path 34 of the passage electrons in the vicinity of the convex pole face 44 and is of is, and emerges at the surface 29 after being influenced by a stronger magnetic deflection field Has been deflected by 90 °. Similar to the lower energy side; through appropriate training there is an electron whose energy is 20% choice of the strength and shape of the deflection magnet If the average energy of the electrons is 30 th, the electrons of different energies become unthinkable Beam 11, a longer path 36 deflected back and forth between the approximately the same angle. Poles of the deflecting magnet 22, the exit from the The angle through which the deflected electron deflecting magnet 22 is carried out parallel to the beam 37 with respect to its normal direction Lower speed electrons. deflecting the deflection magnet 38 depends on

The exit surface 29 of the deflecting magnet 22 35 the strength of the magnetic field of the magnet. The deflected cathode ray 37 is deflected back and forth 45 ° with respect to the direction of the cathode ray in the widening deflection stage 11 can be set by rotating the semi-circular 16 of the chamber 13 and passing through the elongated mige pieces the inclination of the exit surface 29 to window 17, so that a surface 47 of an object allow change or by the entire deflection 40 48, which is tilted by a conveyor magnet, not shown, if an angle other than the direction below the deflected cathode ray 45 ° is required is moved around all electrons, is swept over. In this way, different energies will escape parallel to each other to let the surface of the object 48 in a certain way. As a result of the way in which the deflecting magnet 22 irradiates patterns with electrons. Because an electron of different energy deflects by the same voltage of a certain triangular shape for the deflection angle, if a deflected electron magnet 38 is used, the cathode beam 37 is exited from the exit surface 29 of the deflecting beam via the object 48 with a constant velocity magnet whose electrons are deflected at different speeds so that a zigzag pattern decelerates. The deflected electron stands, or a pattern of parallel paths can be directed onto beam 37, is then directed between the pole pieces of a 50 to the object by using another saw deflection magnet 38, the deflection tooth voltage being generated in the magnet 38,
magnet an alternating current-fed electromagnet The deflection device, consisting of the tube that deflects the deflected electrons 37 in a tube 14, the attachment tube 15 of the chamber 13, the focusing perpendicular to the axis of the electron beam, the siermagneten 21, the deflecting magnet 22 and the 11, so that the deflected electron beam 55 deflecting magnet 38 is located in a housing 37 is deflected over an object which is 49, and this housing 49, as well as the chamber of the deflecting part 16 is located. The deflector 13, through the rotary coupling 18 to the accelerator magnet 38, has a pole piece 39 with a concave pole step 12 so that a rotation around surface 41, a winding 42 and a pole piece 43 can take place along the axis of the cathode ray 11 with a convex pole face 44 and a further 60 and the deflecting beam after each desired directional winding 45. The pole shoes 39 and 43 are arranged horizontally with respect to the axis of the electron beam and lie outside the chamber 13 11 can be brought. The cathode ray 11 near the tip of the widening part can also be deflected by angles other than 90 °; the pole shoes are arranged on a yoke 46, and in this case the chamber 13 must have a shape on the axis of the electron beam 11 65 such that the deflected cathode is aligned, the convex pole face 44 of the pole beam being able to penetrate it.

shoe 43 on the side of the deflection assembly 16 The housing 49 forms an evacuated chamber

which is the side of the high energy of the surrounding a funnel-shaped widening approach on the

Floor area, the deflecting magnets and the deflecting magnets being arranged in the housing itself are, so that the chamber 13 can be omitted. In such a case, the deflection magnets and the Deflection magnet adjustment means are provided which allow the magnets to be adjusted for the purpose of deflect the electron beam by a desired angle. The deflecting magnet 22 can also be included Adjusting means be equipped so that electrons of different energies at the output window 17 as possible converge and only a small width of the window is required.

In Fig. 2, the electron distribution of the electron beam 11 is shown in cross section. There all electrons of the same energy are not concentrated in one point of the cross-section of the cathode ray are, the deflection device must focus all electrons of the same energy so that one desired deflection of the cathode ray takes place. Electrons from different parts of the cross-section shall be discussed below to explain the influence that is placed on them in the deflector is exercised. Accordingly, points 51, 52, 53, 54 and 55 will be on the axis of the ray, bottom, top and left and right selected. In Fig. 3, the electron trajectories for electrons of the Beam 11 shown, and the arrangement of the deflector is in a vertical direction of the cathode beam 11 traversing direction shown, wherein the cathode ray through the deflection magnet 38 and the pole faces of the deflecting magnet 22 is passed. In this figure are the rays that make the vertical Corresponding positions 51, 52 and 53 in the cross section of the cathode ray of FIG. 2, and the paths 34, 35 and 36 through the deflecting magnet 22 result for different electrons Energy. In the path 34 electrons of medium energy run from the axis 51 of the cathode ray on the path 56 through the deflecting magnet 22 and occur after a deflection of 90 ° its exit side. Medium-energy electrons, which in the cross-section of the cathode ray 11 at 53 at the top or at 52 at the bottom, take the paths 57 and 58, the path 57 being shorter and path 58 is longer than path 56. In a similar "way, electrons whose energy is 20% is below the mean energy if they are the vertical points 51, 52 and 53 of the cathode ray cross-section enforce the paths 59, 61 and 62 through the deflecting magnet; Electrons whose Energy is 20% above the mean value and the vertical positions 51, 52 and 53 of the Enforce cathode ray cross-section, have the paths 63, 64 and 65 through the deflection magnet 22, whereby the electrons that penetrate the point below in the cross section of the cathode ray always switch be deflected at an angle that is a little less than 90 °, and the electrons that have an upper body 53 of the cathode ray cross-section are deflected by an angle that is slightly larger is than 90 °. All electrons of the same energy go through a focal point after they have the Have passed through the exit surface 29 of the deflecting magnet 22; here are the focal points for the electrons the mean energy and the electrons of the 20% lower energy and the electrons of the 20% higher energy labeled 66, 67 and 68. After the electrons are the focal points have passed through, the electrons run with the same energy in the cross section of the cathode ray 11 occurred above and below, on diverging orbits.

In Fig. FIG. 4 is a cross-sectional view of the FIG. 3 shown arrangement according to the cutting line 4-4 are shown in the direction of the arrows, and the playback paths which take the horizontal in With respect to the axis offset points of the cathode beam cross-section 11 correspond. Electrons all Energy, soft in the cathode ray cross section 11 the left and right lying points 54 and 55 enforce, behave essentially in the same way as electrons that run along the axis 51, insofar as the in Fi g. 3 discussed diversion comes into question. Electrons representing the vertical median plane of the cross section of the cathode ray 11, pass through the center plane 69 between the pole pieces 24 and 26. On the other hand, electrons pass through the left and right places 54 and 55 of the cross-section correspond to paths 71 and 71 lying outside the central plane 72 by the deflecting magnet 22 and are subject to focusing and defocusing influences through the edge fields of the pole shoes 24 and 26.

In Fig. 5 the lower part of the deflecting magnet 22 is shown, and the magnetic edge fields, which are shown on the deflected electron beam 37, which is directed vertically downwards, wherein the exit surface 29 forms an angle of 45 ° with respect to the horizontal, while on the other hand is characterized by 73 a horizontal exit surface. When an electron beam between the poles of a magnet, perpendicular to the exit surface of the same, and electrons emerge run outside the center plane 69, for example on the axially offset tracks 71 and 72, so the electron beam is only influenced by the deflection of the magnetic field, but it is not steered to the pole faces or away from the same. A magnetic fringe field, which is created by the line of force 74 is characterized at the horizontal exit plane 73, acts on electrons in the middle plane 69 run, with a magnetic field strength of 75, which are perpendicular to the electron path and which is also perpendicular to the magnetic pole faces, so that a deflection force 76 results, which, as discussed above, deflects the electron beam. Influence the magnetic fringe fields meanwhile the electrons, which run on the paths 71 and 72 lying on the sides with a magnetic one Field strength 77, which has a component 78 which is perpendicular to the electron path and is to the magnetic pole faces and thereby causes a deflecting force 79; further lies one Component 81 is present, which lies parallel to the electron path and has no influence on the electrons. If, however, an electron beam between the poles of a magnet is not perpendicular to the exit surface of the same emerges, then acts on the electrons, which run outside the center plane 69, a force tending to steer the electrons towards or away from the center plane, as the case may be, the electrons are directed more towards the normal to the exit surface or away from it are. The magnetic fringe field is represented by the line of force 82 on the exit surface 29, the exit surface 29 being inclined by approximately 45 °

lies; a magnetic field component results for the electrons running in the central plane 69 83 perpendicular to the electron path and to the magnetic pole faces, which is a deflecting Force 84 results in redirecting the cathode ray as previously discussed. The magnetic fringe field but affects the electrons traveling on the outer tracks 71 and 72 with one magnetic force, which is a component 86 perpendicular to the path of the electrons and to the Has pole faces and is expressed in a deflecting force 87; but there is also a component 88, which lies in a plane which is the component 88 and which is parallel to the central plane 69 contains offset electron beam. Component 88 can be broken down into two components 89 and 91, which lie in the plane containing the component 88 and the electron path, where the components 89 is perpendicular to the electron path and results in a defocusing force 92, while component 91 is parallel to the path of the electrons and none on the electrons Exerts force. Such magnetic fringe fields consist of lines of force that arise from the exit surface of the magnetic field bulging out, with electrons lying on the sides Run because of 71 and 72, are subject to a defocusing influence which acts in opposite directions and defocused the whole cathode ray.

Therefore, if a magnet deflects a cathode ray to the normal of the exit surface, this results in the fringe magnetic field a defocusing on this surface, while when the cathode ray is directed away from the direction of the normal of the exit surface, a focusing influence in the magnetic fringe field. Meanwhile, a cathode ray, which is deflected towards the normal of this surface when entering the magnetic field, focused by the fringe magnetic field, while an electron beam, which is from the normal of this Surface is bent away, is subject to defocusing.

The defocusing influence arises on the exit surface 29 of the deflecting magnet when the Exit surface 29 is inclined about 45 ° with respect to the horizontal, so that the electrons are different-η he energy emerge parallel to each other. The entry surface 29 of the deflecting magnet 22 can with respect to their inclination can be adjusted so that they form an angle of about 30 ° with respect to the horizontal forms, for which purpose the rotatable portion 32 is provided, whereby the cathode ray 11 is directed to the center plane 69, in view of the focusing influence of the magnetic Fringing field at the entrance surface of the magnet with respect to the cathode ray 11; through this there is a compensation of the defocusing effect at the exit surface, and it becomes the width of the area irradiated on the object changed. In the example shown, the entry surface 28 is only around 30 ° inclined, while the exit surface 29 is inclined by 45 °, so that the exiting at the magnet 22 Cathode ray diverges and forms an irradiated area that is wider than the width of the cathode ray 11.

In Fig. 6 shows a cross section of the lower part of the deflection magnet 38, a cross section of the deflected cathode ray 37 being shown as it exits the deflection magnet 38. The deflected cathode beam 37 has a cross section which is approximately elliptical, with electron paths of different energies appearing to be drawn apart linearly. In the cross section of the deflected cathode beam 37 are different elliptical cross-sections for the electron-medium energy and those 20% lower energy and 2O ^o / o higher energy corresponding to the panels 34, shown 35 and 36, wherein the orbits of the electrons, which in cross-section the points 52, 53, 54 and 55 of the cathode ray 11 pass through, lying on the ends and on the sides of the ellipse of each energy level. The deflected cathode ray 37 is deflected back and forth by the deflection magnet 38 over an essentially rectangular area 93.

Because of the curved pole faces of the deflecting magnet 38, the density of the lines of force is magnetic Field between the pole pieces of the deflection magnet 38 on the convex pole face 44 is greater than at the concave pole face 41. Since the radius of curvature of the convex pole face 44 is greater than the Is the radius of curvature of the concave pole face 41, the gradient of the force flux density takes between the pole faces 41 and 44, the desired gradient of the density of lines of force between the pole faces 41 and 44 by using pole faces of suitably different selected radii of curvature is achieved. The magnetic deflection component perpendicular to the direction of deflection acts on the deflected cathode ray 37 and deflects it back and forth; because the gradient of the force flux density between the pole faces 41 and 44 increases towards the convex pole face 44, all Electrons of the deflected cathode ray 37 deflected by approximately the same angle because the Electrons of higher energy are in the vicinity of the convex pole face 44.

The pole faces of the deflection magnet 38 can also have a different shape, for example run straight in the vertical plane and semi-cylindrical or V-shaped in the horizontal plane be; it can also be surfaces that are curved in the vertical direction as long as there is only one Gradient of force line density results. As one such example, FIG. 6 A is the concave pole face in horizontal cross-section shown as V-shaped, and here, too, there is a gradient of the force flux density between the pole faces, which increases from the concave pole face to the convex pole face 43.

In the F i g. 7 and 8 a further embodiment is shown. The cathode ray 11 is from an accelerator stage 12 passed through an evacuated chamber 49, in which a deflection an angle of 90 °, for example, is carried out using a deflecting magnet, which is similar to the magnet 22 previously described is. The cathode ray becomes perpendicular to the axis of the cathode ray 11 pivoted back and forth by mechanical movement of the deflecting magnet 22 so that in this way the deflection of the cathode ray takes place. The mechanical movement of the deflection magnet 22 can be achieved in that an oscillating movement on the yoke part 96 of the deflection magnet 95 is exercised by the yoke part 96 being pivotable about an axis in a ball bearing 97, which with the axis of the cathode ray 11 to-

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collapses. A flywheel 101 is arranged on a drive shaft 103 , the shaft 103 being rotated by a motor 104 which is arranged on the inside of the upper wall of the housing 49. When the flywheel 101 rotates, the rod 98 is moved up and down and an oscillating motion is transmitted to the deflecting magnet 95.

It is evident that the size of the deflected spot can be adjusted in various ways can. The width of the spot in the direction of the deflection can be adjusted, for example, " that the angle of the entrance surface 28 of the deflection magnet 22 is changed or the cathode ray is first focused by the four-pole focusing magnet 21. The length of the stain can be changed by changing the angle of the exit surface 29 of the deflecting magnet 22 is by changing the field strength of the deflecting magnet or a first focus by the four-pole focusing magnet 21 is made.

The axis of the accelerator stage 11 need not be horizontal, but in general this will be desirable.

Claims (9)

Patent claims: 1. Method for irradiating by means of a particle beam of charged particles of the same rest mass, in which a practically parallel bundle of rays of preferably circular Cross section in a magnetic field, the lines of force of which are perpendicular to the bundle axis, directed by deflection by 90 ° onto the surface to be irradiated and thereby in a strip-shaped beam Cross-section is formed, characterized in that the in the original beam randomly distributed over the cross-section of different particles Velocity through the magnetic field in such a way spatially separated from each other and in different Focal points are focused that, after passing through the magnetic field, the surface elements in the longitudinal direction of the stripe of particles of different velocities and in the Stripe transverse direction are formed by particles of essentially the same speed, and that the entire strip-shaped bundle of rays is driven by a second magnetic field in the transverse direction of the strip periodically deflected and pivoted over the surface to be irradiated. 2. Arrangement for carrying out the method according to claim 1, characterized in that the second magnetic field supplying the periodic deflection field has such a gradient of the magnetic field produces that the particles of higher velocity of the beam through parts of the deflection field be steered, in which the gradient of the magnetic flux is greater than at the parts through which the lower velocity particles are directed. 3. Arrangement according to claim 2, characterized in that the pole pieces of the generation of the second magnetic field provided electromagnet concave or convex surfaces which are substantially complementary to each other, and that the radius of curvature of the concave pole piece is smaller than the radius of curvature of the convex pole piece. 4. Arrangement according to claim 3, characterized in that that the radii of curvature of the pole pieces are so different that in the vicinity of the convex pole piece the highest Density of magnetic flux results. 5. Arrangement according to one or more of claims 2 to 4, characterized in that for the purpose of the entry coil of the jet in the first intended for speed separation To be able to adjust the magnetic field on the entry side of the field between the generation of the same provided pole pieces each one rotatable made of magnetic material Segment is provided. 6. Arrangement according to one or more of claims 2 to 5, characterized in that for the purposes of the exit angle of the jet from the to achieve the velocity separation provided magnetic field to be able to set the intended for generating this magnetic field Magnet arrangement rotatable about an axis perpendicular to the path of the particles in is arranged with respect to the electrode system feeding the beam of the magnet arrangement. 7. Arrangement according to one or more of claims 2 to 6, characterized in that the beam consisting of the charged particles before it enters the magnetic field causing the velocity separation through a focusing magnet which consists of four magnetic poles. 8. Arrangement according to one or more of claims 2 to 7, characterized in that the means for generating the magnetic field causing the speed separation and preferably also the means for generating the second, the periodic deflection Field are arranged outside the vacuum housing of the arrangement and that the vacuum housing has an inlet opening and an outlet opening and means are provided which to rotate the housing and the means for generating the two magnetic fields with respect to allow the direction of the beam to be adjusted. 9. Arrangement according to one or more of claims 2 to 7, characterized in that the means for generating the magnetic fields are arranged in a vacuum vessel, which has an inlet opening and an outlet opening for the particles forming the beam. Considered publications: German Patent Nos. 706 382, 750 159; German Auslegeschrift No. 1 010 201; U.S. Patent No. 2,737,593; The Physical Review, Vol. 45, 1934, No. 10,
Pp. 724 to 727; M. v. Ardenne, "Tables of Electron Physics, Ion Physics and Super Microscopy", 1956, Berlin, Vol. 1, p. 474. For this purpose 2 sheets of drawings 709 617/392 7. 67 © Bundesdruckerei Berlin