US3351793A - Septum extraction electrode comprising a plurality of parallel wires under tension - Google Patents

Septum extraction electrode comprising a plurality of parallel wires under tension Download PDF

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Publication number
US3351793A
US3351793A US505152A US50515265A US3351793A US 3351793 A US3351793 A US 3351793A US 505152 A US505152 A US 505152A US 50515265 A US50515265 A US 50515265A US 3351793 A US3351793 A US 3351793A
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United States
Prior art keywords
septum
cyclotron
electrode
wires
under tension
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Expired - Lifetime
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US505152A
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English (en)
Inventor
Steimel Karl
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Licentia Patent Verwaltungs GmbH
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Licentia Patent Verwaltungs GmbH
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H7/00—Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
    • H05H7/10—Arrangements for ejecting particles from orbits

Definitions

  • ABSTRACT 0F THE DISCLGSURE For use in a cyclotron, a deflecting condenser composed of a plurality of tensioned Wire portions extending perpendicular to the direction of movement of the cyclotron beam and arranged to undergo an oscillatory motion in the direction of their length so as to vary the point at which the cyclotron beam strikes each element, thus permitting the condenser to be exposed to high power beams.
  • the present invention relates to a device for use in a cyclotron, and particularly to a septum, or deflecting condenser, for causing a stream, or beam, of accelerated particles to exit from a cyclotron.
  • the prior art devices of this type generally comprise two elongated electrodes which are spaced opposite each other and at a given distance apart.
  • the prior art septa are invariably arranged to have an inner electrode which lies in the current region of the cyclotron, and which is thus struck by a stream of particles present in the cyclotron.
  • This arrangement has been found to possess the drawbacks of reducing the intensity of the cyclotron beam and of causing the septum to eX- perience appreciable heating. Consequently, the inner electrode becomes bent and hence begins to act as an extremely high catching resistance for the exiting particle stream.
  • the inner electrode be comes considerably eroded at the point where it is first struck by the stream, thereby producing a distortion of the electric field. The over-all result is a great loss of particles and a deterioration of the optical characteristics of the beam.
  • an improved septum is achieved by forming its inner electrode, which is to be exposed to the beam, to have a plurality of elements, which are preferably constituted by thin wires, oriented substantially perpendicular to the plane of movement of the particles forming the beam.
  • these elements are arranged to undergo a continuous motion in the direction of their length so as to continuously vary the point at which the beam strikes each element.
  • FIGURE 1 is a schematic illustration of a cyclotron equipped with a septum.
  • FIGURE 2 is a side view of an electrode constituting the inner electrode of a prior art septum indicated in FIGURE 1.
  • FIGURE 3 is a side view of an improved inner elec trode according to the present invention.
  • FIGURE 1 there is shown a cyclotron having a main septum constituted by electrodes 1 and 2.
  • the electron beam 3 is constituted by positive ions
  • the outer electrode 2 is at a negative high voltage potential and the inner electrode 1 is grounded.
  • the beam 3 passes between the two electrodes.
  • FIGURE 2 shows an inner electrode 1 according to the prior art, which electrode may be made of tungsten.
  • the prior art septum having an electrode as shown in FIGURE 2 presents several serious drawbacks.
  • the most difficult problem associated with such a septum resides in the fact that the inner electrode 1, which lies in the current region of the cyclotron, is struck by the stream of particles produced by the cyclotron. This causes a loss in beam intensity and an appreciable heating of the electrode. Consequently, the inner electrode 1 becomes bent and begins to act as an extremely high catching resistance for the stream of particles.
  • FIGURE 3 there is shown an inner electrode 1' for a septum constituting a. preferred embodiment of the present invention.
  • This electrode is shown to include a large number of wires 4 which are for example, each bent to have a U-shaped, or hairpin, configuration.
  • the two free ends of each bent wire 4 are attached, by soldering or welding for example, to a strut 5 of a frame whose other strut 6 is provided with a plurality of springs 7 each of which engages the bend of a respective one of the Wires 4.
  • the pull exerted by each spring 7 acts to place the wires 4 under tension.
  • the wires 4 can be made, for example, of tungsten, the diameter of the wires being approximately 50p and the wires being spaced from each other by a distance of about 1 mm.
  • the electrode 1' shown in FIGURE 3 is positioned in the cyclotron in the manner shown for the electrode 1 that the individual wires 4 are positioned at right angles to the plane in which the particles in the cyclotron stream move, this plane being parallel to the plane of FIGURE 1.
  • the inner electrode of FIGURE 3 is constituted by a series of individual wires 4, each producing an electric field, the composite electric field along the electrode will have a somewhat periodic nature. However, by maintaining the distance between the wires 4 small with respect to the separation between the electrodes 1 and 2, the periodic nature of the field of the electrode 1' has a negligible etfect on the operation of the unit.
  • the septum can be mounted so that, for high loads, the inner electrode 1' is moved in such a manner that the point at which the beam will impinge on wires 4 will be continuously varied. This may be accomplished, for example, by mounting the entire septum 1'2 on a unit which causes it to oscillate in a direction parallel to the axis of the cyclotron, this direction being indicated by the double arrow 9 of FIGURE 3.
  • FIGURE 3 Such an arrangement is shown in FIGURE 3 wherein the struts 5 and 6 are mounted on a post 14 which is disposed on a mechanical oscillating unit 15.
  • This unit may be constituted by any well known type of device for producing mechanical oscillations, such as the movable core of an A.C. excited solenoid, or a motor driving a cam or a plate to which the post 14 is eccentrically coupled.
  • the electrode 1 of FIGURE 3 can also be constructed to have a series of closed wire loops in place of the hairpin wires of FIGURE 3.
  • Each of these loops can be disposed between a pair of rollers which are continuously driven so as to cause a continuous movement of the wires which will cause the straight portions thereof to advance in the direction of the arrow of FIGURE 3.
  • the movement of the wire loops will have the same effect as the previously-described oscillation of the entire septum.
  • Arrangements of this type can be given a very small length, as short as 1 cm. for example, and can also be used to constitute an input septum which functions to deflect a portion of the beam produced by the cyclotron in order to reduce the load on the output septum to a sufliciently small value.
  • such an input septum which is shown as a septum 11, 12 in FIGURE 1, is preferably arranged in the path of the beam at a position 90 ahead of the main septum, which angle is taken about a circle whose center coincides with the axis of the cyclotron.
  • a septum electrode having a plurality of thin wires is provided together with suitable means for 50 moving the electrode that the point at which the cyclotron beam strikes the wires is continuously varied.
  • an additional septum which is arranged on the path of the cyclotron beam approximately 90 ahead of the main septum for reducing the load to which the main septum will be subjected.
  • an inner electrode to be exposed to the beam and comprising a plurality of elements each constituted by a wire placed under mechanical stress and oriented substantially perpendicular to the plane of movement of the particles forming the beam, said wires being in pairs, each of which pairs is constituted by a single piece of wire in the form of a hairpin, said electrode further comprising a holder to which the free ends of each hairpin are attached, and resilient means engaging the bend of each of said hairpins for maintaining said hairpins under tension.
  • An arrangement as defined in claim 1 further comprising an additional septum arranged in the path of said beam at a point ahead of said electrode, with respect to the direction of movement of the beam, and at an angle of to said electrode with respect to a circle centered on the axis of the cyclotron.
  • an inner electrode to be exposed to the beam and comprising a plurality of elements oriented substantially perpendicular to the plane of movement of the particles forming the beam, and driving means to which said electrode is connected for causing said wires to move in a direction parallel to their axes for causing the point at which the cyclotron beam strikes each of said wires to be continuously varied.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Particle Accelerators (AREA)
US505152A 1964-10-28 1965-10-25 Septum extraction electrode comprising a plurality of parallel wires under tension Expired - Lifetime US3351793A (en)

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DEL0049140 1964-10-28

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US3351793A true US3351793A (en) 1967-11-07

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US (1) US3351793A (xx)
CH (1) CH438513A (xx)
DE (1) DE1251886B (xx)
FR (1) FR1454654A (xx)
NL (1) NL6514001A (xx)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8575867B2 (en) 2008-12-05 2013-11-05 Cornell University Electric field-guided particle accelerator, method, and applications

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2467390A (en) * 1945-10-29 1949-04-19 Raytheon Mfg Co Filament support for electric space discharge tubes
US2586494A (en) * 1947-10-11 1952-02-19 Bbc Brown Boveri & Cie Apparatus for controlling electron path in an electron accelerator
US2626351A (en) * 1948-08-17 1953-01-20 Wilson M Powell Beam extractor
US2789221A (en) * 1954-04-20 1957-04-16 Cornelius A Tobias Method and apparatus for nuclear particle acceleration
US2954497A (en) * 1958-11-25 1960-09-27 Sylvania Electric Prod Temperature compensating grid
US3177393A (en) * 1960-10-14 1965-04-06 Philips Corp Cathode for an electric discharge tube

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2467390A (en) * 1945-10-29 1949-04-19 Raytheon Mfg Co Filament support for electric space discharge tubes
US2586494A (en) * 1947-10-11 1952-02-19 Bbc Brown Boveri & Cie Apparatus for controlling electron path in an electron accelerator
US2626351A (en) * 1948-08-17 1953-01-20 Wilson M Powell Beam extractor
US2789221A (en) * 1954-04-20 1957-04-16 Cornelius A Tobias Method and apparatus for nuclear particle acceleration
US2954497A (en) * 1958-11-25 1960-09-27 Sylvania Electric Prod Temperature compensating grid
US3177393A (en) * 1960-10-14 1965-04-06 Philips Corp Cathode for an electric discharge tube

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8575867B2 (en) 2008-12-05 2013-11-05 Cornell University Electric field-guided particle accelerator, method, and applications

Also Published As

Publication number Publication date
FR1454654A (fr) 1966-02-11
NL6514001A (xx) 1966-04-29
DE1251886B (xx)
CH438513A (de) 1967-06-30

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