US3325713A - Apparatus for injecting charged particles into the magnetic field of a cyclic particle accelerator - Google Patents

Apparatus for injecting charged particles into the magnetic field of a cyclic particle accelerator Download PDF

Info

Publication number
US3325713A
US3325713A US218703A US21870362A US3325713A US 3325713 A US3325713 A US 3325713A US 218703 A US218703 A US 218703A US 21870362 A US21870362 A US 21870362A US 3325713 A US3325713 A US 3325713A
Authority
US
United States
Prior art keywords
field
injector
magnetic field
source
injection
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US218703A
Other languages
English (en)
Inventor
Seidl Milos
Sedlacek Zdenek
Sunka Pavel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Czech Academy of Sciences CAS
Original Assignee
Czech Academy of Sciences CAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Czech Academy of Sciences CAS filed Critical Czech Academy of Sciences CAS
Application granted granted Critical
Publication of US3325713A publication Critical patent/US3325713A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H05H7/08—Arrangements for injecting particles into orbits

Definitions

  • the present invention relates to cyclic accelerators of electrons and ions, and deals more particularly with a device for injecting charged particles into the magnetic field of an accelerator.
  • the invention will be explained in its application to a betatron, it being of course understood, that the invention is in no way limited to this particular type of apparatus and can be used in connection with any suitable accelerator.
  • the trajectory of the electrons within the deflector is substantially influenced by the arrangement of the magnetic field of the accelerator, which can difler in products of various origin. If the aperture of the deflector is not sufliciently large, injected particles may be lost on the deflector electrodes.
  • An electrostatic deflector requires a separate high voltage source.
  • the angle under which the charged particles are injected into the guiding magnetic field of the accelerator is constant during the injection period (lasting several microseconds) only if the voltage across the gun and across the deflector varies with time in the same manner, which is diflicult to achieve.
  • a variation in the injection angle with time results in a reduction in the magnitude of the captured charge.
  • the aforesaid difliculties are avoided according to the invention by the provision of a channel that is shielded from the magnetic field and therefore free from deflecting magnetic forces, said channel serving for the admission of electrons to the magnetic field.
  • FIG. 1 is a diagrammatic representation showing the vacuum chamber and injection device of a betatron
  • FIG. 1a shows the injector of FIG. 1 and the windings connected thereto
  • FIG. 2 shows the injector tube of the apparatus of FIG. 1 in a perspective view and partly in transverse section
  • FIG. 3 shows a modified compensating arrangement for the betatron of FIG. 1 in a diammat-ric view.
  • an electron gun 3 mounted in a tangential tubular extension of a vacuum chamber 2.
  • the vacuum chamber is placed in the usual way in the magnetic field of a betatron.
  • the electron gun is positioned outside the poles of the betatron magnet, and can therefore easily be designed for the required resistance against high voltage and for correct focussing of the beam.
  • the gun produces a cylindrical electron beam with an energy of for instance kev., which is focussed so as to make the beam divergence in the plane A at the end of an injector tube 4 equal to zero.
  • the injector tube 4 is coaxially aligned with the electron gun 3. It is connected to the semi-conductive coating of the vacuum chamber 2 and grounded thereby.
  • the gun, as well as the injector tube, are made of a ferromagnetic material of high permeability, which shields the electron beam 5 from the external guiding magnetic field.
  • the magnetic field is d (A -U 1 D I times smaller than the magnetic field outside the injector, tube.
  • the electron beam 5 passes from the cathode 6 in the gun 3 to the plane A through a negligibly small magnetic field, independent of the external guiding field.
  • the electron beam Having passed the plane A, the electron beam enters the guiding magnetic field of the betatron tangentially to an orbital circle having a centre S and passing through the intersection M of the injector axis with the plane A.
  • Small corrections of the injector angle may be required to correct errors in the mounting of the vacuum chamber in the magnet, and can be effected by a system of deflection plates similar to those'usedin a cathode ray tube.
  • FIG. 1 shows deflection plates 7 for deflecting the'beam in a horizontal plane and plates 8 for deflection a 3 vertical plane.
  • the diameter D of the cylindrical injector tube 4 is preferably just slightly larger than the diameter of the electron beam and, with a correctly focussed beam, it may amount to 5-10 mm.
  • the device of the invention provides a channel in the magnetic field of the betatron which is substantially free from the disadvantages of an electrostatic deflector, but it causes a deformation of the external magnetic field.
  • the injector tube As the injection of electrons into the betatron takes but a very short fraction of the accelerating cycle (about 1.5 l'0* of the cycle), we make the injector tube from a magnetically soft material whose hysteresis loop is of substantially rectangular shape. We select the wall thickness of the injector tube in such a manner that at the moment when the injection is terminated, the magnetic induction in the injector wall is equal to the saturation limit :13, of the injector material.
  • the injector tube material When injection is terminated, the injector tube material immediately becomes magnetically saturated and, after a'certain time, its permeability drops to nearly 1, whereby the injector does not cause a deformation of the external magnetic field, and the force action on the injector drops almost to zero. If the magnetic induction of the guiding field equals B then the wall thickness of the injector tube must be When the wall thickness is chosen according to the preceeding formula, and the permeability of the material amounts to the magnetic field within the injector does not exceed 1% of the external guiding field, so that the path of electrons within the injector is, to all practical purposes, not influenced by the external field. When stronger shielding from the external magnetic field is i: I sin (,0
  • the angle (,0 is shown in FIG. 2. It is in a radial plane with respect to the common axis of the tube 4 and the beam 5, and has its apex in the axis.
  • a sinusoidal current density distribution can be effected, for example, by means of a winding 9 shown in FIGS. 1 and 2.
  • the current feeding the compensation winding can be derived from the current which energizes the winding 110 of the guiding magnet 11 by means of a saturable transformer.
  • the transformer core 12 is preferably made from the same material as the injector tube 4, and the winding of the transformer 12 is designed so as to make the saturation in the transformer core equal to the indution B of the injector tube material at the magnet when injection is terminated. This ensures a variation of the compensating current in precise synchronization with variations in the intensity of the magnetic field.
  • the primary winding of the transformer 12 is connected in series to the magnet winding 110 which ensures the correct maximum value of the compensating current independent of fluctuations to which the power supply of the betatron magnet 11 may be subjected.
  • the deformation of the guiding magnetic field caused by the injector tube 4 maybe compensated, alternatively,
  • the forces acting on the injector tube are very small because the material of the injector becomes saturated soon after the injection. For instance, in a betatron of 15 mev., the force will exceed not 10 to 20 grams per centimeter of injector tube length. If the injector is properly designed, such a force is unable to influence its operation or to overcome its mechanical strength.
  • said source being adapted to generate said beam in an injection pulse of limited duration, and said injector member being dimensioned to reach magnetic saturation in said field in a time not substantially exceeding said period,
  • said compensating means including means for passing an electric cur-rent axially over said injector member, the density of said current being sinusoidally distributed about said axis, and means for varying the magnitude of said current in synchronization with variations of the intensity of said field.
  • said electromagnetic means including an energizable accelerator magnet having a winding, said current passing means including a saturable transformer, and a compensating conductor means on said injector member, said transformer having a primary winding in series circuit with the winding of said accelerator magnet, a secondary winding in circuit with said conductor means, and a core of magnetically soft ferromagnetic material dimensioned to reach magnetic saturation in a time not substantially exceeding said period when said magnet is being energized.
  • said electromagnetic means including a magnet having two poles, said portion of said injector member being interposed between said poles, and said compensating means including .a plurality of strips of ferromagnetic material inter- Posed between said injector member and 'said'poles, said strips being dimensioned to reach magnetic saturation in said field in a time not substantially exceeded said period.
  • a chamber adapted to be evacuated, said chamber having an arcuate Wall and a tubular extension projecting substantially tangentially outward of said chamber from said wall, said electromagnetic means generating said field in said chamber and defining said path in said chamber, said source being mounted in said extension, and said injector member extending from said tubular extension into said chamber, said longitudinal portion of the injector member being in said chamber.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Particle Accelerators (AREA)
US218703A 1961-08-25 1962-08-22 Apparatus for injecting charged particles into the magnetic field of a cyclic particle accelerator Expired - Lifetime US3325713A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CS517461 1961-08-25

Publications (1)

Publication Number Publication Date
US3325713A true US3325713A (en) 1967-06-13

Family

ID=5396122

Family Applications (1)

Application Number Title Priority Date Filing Date
US218703A Expired - Lifetime US3325713A (en) 1961-08-25 1962-08-22 Apparatus for injecting charged particles into the magnetic field of a cyclic particle accelerator

Country Status (4)

Country Link
US (1) US3325713A (de)
CH (1) CH404820A (de)
DE (1) DE1191053B (de)
GB (1) GB995158A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3523209A (en) * 1967-06-29 1970-08-04 Gulf General Atomic Inc Plasma device including plasma injection structure and method
US3667058A (en) * 1970-04-08 1972-05-30 Atomic Energy Commission Electrostatic accelerated-charged-particle deflector
US4608537A (en) * 1984-06-14 1986-08-26 The United States Of America As Represented By The Secretary Of The Navy Low perturbation electron injector for cyclic accelerators

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2497891A (en) * 1945-09-19 1950-02-21 Univ Illinois Betatron injector structure
US2721949A (en) * 1949-10-31 1955-10-25 Gund Konrad Betatron
US2812463A (en) * 1951-10-05 1957-11-05 Lee C Teng Magnetic regenerative deflector for cyclotrons
US2830211A (en) * 1957-07-10 1958-04-08 Herman F Kaiser Microtron extraction tube

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2905842A (en) * 1957-11-22 1959-09-22 Willard H Bennett Device for producing sustained magnetic self-focusing streams

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2497891A (en) * 1945-09-19 1950-02-21 Univ Illinois Betatron injector structure
US2721949A (en) * 1949-10-31 1955-10-25 Gund Konrad Betatron
US2812463A (en) * 1951-10-05 1957-11-05 Lee C Teng Magnetic regenerative deflector for cyclotrons
US2830211A (en) * 1957-07-10 1958-04-08 Herman F Kaiser Microtron extraction tube

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3523209A (en) * 1967-06-29 1970-08-04 Gulf General Atomic Inc Plasma device including plasma injection structure and method
US3667058A (en) * 1970-04-08 1972-05-30 Atomic Energy Commission Electrostatic accelerated-charged-particle deflector
US4608537A (en) * 1984-06-14 1986-08-26 The United States Of America As Represented By The Secretary Of The Navy Low perturbation electron injector for cyclic accelerators

Also Published As

Publication number Publication date
CH404820A (de) 1965-12-31
DE1191053B (de) 1965-04-15
GB995158A (en) 1965-06-16

Similar Documents

Publication Publication Date Title
US3075115A (en) Ion source with space charge neutralization
GB1326279A (en) Mass spectrometers
US3325713A (en) Apparatus for injecting charged particles into the magnetic field of a cyclic particle accelerator
Alfassi et al. Elemental analysis by particle accelerators
US5053184A (en) Device for improving the service life and the reliability of a sealed high-flux neutron tube
US4128764A (en) Collective field accelerator
US5247263A (en) Injection system for tandem accelerators
US2721949A (en) Betatron
US3723730A (en) Multiple ion source array
US3268730A (en) Apparatus for producing intense bunched beams of monoenergetic neutrons
US3610989A (en) Production and utilization of high-density plasma
US4737726A (en) Charged particle beam storage and circulation apparatus
US3377563A (en) Particle accelerator having beam deflecting means
Elias et al. Recirculating electrostatic accelerators
US2905842A (en) Device for producing sustained magnetic self-focusing streams
Akimov et al. High-power X-band pulse magnicon
US3296442A (en) Short duration neutron pulse generating system
Steski et al. Operation of the relativistic heavy ion collider au− ion source
US2942106A (en) Charged particle accelerator
US2631234A (en) Magnetic induction accelerator
US2970273A (en) Method of producing large circular currents
US2925505A (en) Device for producing sustained magnetic self-focusing streams
Inall Currents in a High-Voltage Ion Accelerator Tube
SU741347A1 (ru) Устройство дл формировани импульсного электронного пучка
Luckey The use of electrostatic generators as injectors for electron synchrotrons