US3408526A - Ion source having an annular permanent magnet - Google Patents

Ion source having an annular permanent magnet Download PDF

Info

Publication number
US3408526A
US3408526A US543118A US54311866A US3408526A US 3408526 A US3408526 A US 3408526A US 543118 A US543118 A US 543118A US 54311866 A US54311866 A US 54311866A US 3408526 A US3408526 A US 3408526A
Authority
US
United States
Prior art keywords
ion source
permanent magnet
ion
magnetic field
annular permanent
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
US543118A
Other languages
English (en)
Inventor
Elenga Cornelis Willem
Reifenschweiler Otto
Schenkelaars Martinus He Maria
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.)
US Philips Corp
North American Philips Co Inc
Original Assignee
US Philips Corp
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 US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3408526A publication Critical patent/US3408526A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/46—Motors having additional short-circuited winding for starting as an asynchronous motor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/02—Details
    • H01J17/14—Magnetic means for controlling the discharge
    • 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
    • H05H3/00—Production or acceleration of neutral particle beams, e.g. molecular or atomic beams
    • H05H3/06—Generating neutron beams

Definitions

  • a permanent magnet positioned behind the non- I apertured plate provides an axial field while an annular magnet, coaxial with the exit aperture, providing a predominant magnetic field in the axial direction, aids the field of the first magnet.
  • a soft iron envelope surrounds the assembly and completes the magnetic circuit.
  • the invention relates to an ion source in which ions are formed in a discharge between two substantially fiat plates as a cathode and a cylindrical anode surrounding the space between the two cathode plates one of which plates has an exit aperture for the ions.
  • An axial magnetic field is produced in the ion source by means of a block of permanent magnetic material, which joins the non-perforated cathode plate. With the exception of the exit aperture for the ions a weak magnetic circuit surrounds the ion source completely.
  • Ion sources of this kind are frequently employed in neutron generators and other ion accelerators.
  • the advantage of such an ion source is that the operational pressure may be low, i.e., to 10 mm. Hg. Furthermore, one voltage source of a few kilovolts is required, While the ion source current need not be very high 'as compared with the resultant ion beam. Because of the closed magnetic circuit, the magnetic stray field outside the ion source is very small, which is required with respect to the acceleration of the ions in the neutron generator or another apparatus in which the ion source is employed. Due to the weak stray field accelerations up to 200 kv. are permissible in one step.
  • ion sources have, however, the disadvantage that it is difiicult to obtain a beam current of more than a few milliamperes with the conventional dimensions of the ion source, i.e., a length of a few centimeters and a diameter of the electrodes of a few centimeters.
  • the ion source forms ions in a discharge between two substantially fiat plates forming the cathode and a cylindrical anode surrounding the space between the two cathode plates, one of which plates has an exit aperture for the ions.
  • An axial magnetic field is produced by means of a block of permanent magnetic material, which joins the non-perforated cathode plate and, with the exception of the exit aperture for the ions, a weak-magnetic circuit surrounds the ion source completely.
  • An annular permanent magnet is arranged on the inner side of a soft magnetic envelope coaxial with the exit aperture for the ions so that the magnetic field of the block of permanent magnetic material is amplified.
  • the strength of the magnetic field near the exit aperture- is very slight, even if this aperture is fairly small. This low strength of the magnetic field results in that the formation of ions at that area is small, so that only a weak ion beam can emanate. Because of the presence of the permanent magnet ring according to the invention the strength of the magnetic field is considerably larger and, especially concentrated more along the axis; therefore, a stronger ion beam can be derived from the discharge.
  • the presence of the permanent magnet ring also permits the enlargement of the exit aperture, which was, in general, from less than one-fifth of the anode diameter, to one-third to one-half of the anode diameter.
  • the diameter of the hole in the permanent magnetic ring is preferably chosen not to exceed the exit aperture in the soft-magnetic envelope.
  • the direction of magnetization of the permanent magnet ring may be axial or radial, provided the magnetic field amplified by the block of permanent magnetic material and the parts of the soft-magnetic envelope operating as pole shoes are sufficiently heavy for minimizing the stray field in the acceleration space.
  • FIG. 1 shows a neutron generator including an ion source according to the invention
  • FIG. 2 shows on an enlarged scale the ion source thereof and FIG. 3 shows graphically the magnetic field of the ion source according to the invention.
  • the neutron generator shown in FIG. 1 comprises a glass cylinder 1, one end of which accommodates a tumbler-shaped acceleration electrode 2, in which the target plate 3 is arranged while at the other end of the glass cylinder 1 a metal cylinder 4 is fastened for supporting the ion source by means of stay rods.
  • the envelope is filled With deuterium-tritium mixture the pressure of which is controlled by a hydrogen replenisher 14, de scribed more fully in US. Patent 3,240,790.
  • the ion source comprises a soft-iron envelope 5 with a rounded-off and perforated upper side 6 and a fiat bottom 7.
  • a block of permanent magnet material 8 bears on the bottom and is coated on the discharge side with a layer of molybdenum 9.
  • On the inner side of the pole shoe 6 a ring 10 of permanent magnet material is magnetized in the same direction as the block 8 While on the discharge side a thin molybdenum plate 11 is arranged.
  • a discharge occurs between plates 9 and 11, which serve as cathodes, the discharge path being surrounded by anode 12.
  • Block 8 has a depression 13 of about one-third of the diameter, the depth being approximately equal to the diameter.
  • the full line A indicates the course of the magnetic field in the ion source shown in FIG. 2 on an enlarged scale; it will be apparent that a small distance from the molybdenum plate 11 the magnetic field has a value of a few hundred gauss.
  • the broken line B indicates the variation of the magnetic field if the ring 10 consists of soft-iron instead of permanent magnet material.
  • the beam current is 0.1 ma. with a current in the ion source of 0.3 ma.
  • the neutron yield is 10 n./sec.
  • the pressure is 10* mm. Hg.
  • the neutron yield during the pulses is 10 n./sec. with a beam current of 1 ma. and an ion source current of 3 ma.
  • the pressure is then about l0 mm. Hg.
  • the beam current is corrected for the secondary electron flow.
  • a neutron generator comprising an ion source according to the invention, having anode diameter also of 20 current and the beam"curr'ent "are” mm. and a diameter of the hole of 10 mm.
  • the ion source -0.2 a. and a neutron yield of 5x10 n./sec. could be obtained.
  • the pressure then was 2 1() mm. Hg.
  • An ion source comprising an envelope of magnetic material having an aperture therein for the passage of an ion beam, a pair of substantially flat, spaced plates within the envelope constituting a cathode, one of said plates having an aperture therein aligned with the aperture in the envelope, a hollow cylindrical anode surrounding the path of the ion beam formed between the cathode plates,
  • annular permanent magnet is magnetized axially.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Power Engineering (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Plasma & Fusion (AREA)
  • Electron Sources, Ion Sources (AREA)
US543118A 1965-04-17 1966-04-18 Ion source having an annular permanent magnet Expired - Lifetime US3408526A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL656504935A NL143727B (nl) 1965-04-17 1965-04-17 Ionenbron.

Publications (1)

Publication Number Publication Date
US3408526A true US3408526A (en) 1968-10-29

Family

ID=19792965

Family Applications (1)

Application Number Title Priority Date Filing Date
US543118A Expired - Lifetime US3408526A (en) 1965-04-17 1966-04-18 Ion source having an annular permanent magnet

Country Status (5)

Country Link
US (1) US3408526A (enrdf_load_stackoverflow)
CH (1) CH446541A (enrdf_load_stackoverflow)
DE (1) DE1252814B (enrdf_load_stackoverflow)
GB (1) GB1083626A (enrdf_load_stackoverflow)
NL (1) NL143727B (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3881132A (en) * 1971-08-19 1975-04-29 California Inst Of Techn Compact, high intensity arc lamp with internal magnetic field producing means
DE3038575A1 (de) * 1980-10-13 1982-04-22 Sergej Ivanovič Tomsk Beljuk Elektronen-ionenquelle
EP0645947A1 (fr) * 1993-09-29 1995-03-29 Societe Anonyme D'etudes Et Realisations Nucleaires - Sodern Tube neutronique à confinement magnétique des électrons par aimants permanents et son procédé de fabrication
EP0660373A3 (en) * 1993-12-21 1996-11-20 Hughes Aircraft Co Punctual light source including a Xenon arc lamp.
CN101965094A (zh) * 2010-10-11 2011-02-02 长春致方达科技有限责任公司 一种球面靶陶瓷中子管及制造方法
CN102711355A (zh) * 2012-06-14 2012-10-03 东北师范大学 潘宁负离子源陶瓷中子管

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112164644A (zh) * 2020-10-26 2021-01-01 大连交通大学 潘宁离子源

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3020408A (en) * 1955-11-14 1962-02-06 Philip W Martin Nuclear analytical apparatus
US3082326A (en) * 1954-03-08 1963-03-19 Schlumberger Well Surv Corp Neutron generating apparatus
GB972191A (en) * 1960-03-08 1964-10-07 Siemens Ag A source of ions
US3216652A (en) * 1962-09-10 1965-11-09 Hughes Aircraft Co Ionic vacuum pump

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3082326A (en) * 1954-03-08 1963-03-19 Schlumberger Well Surv Corp Neutron generating apparatus
US3020408A (en) * 1955-11-14 1962-02-06 Philip W Martin Nuclear analytical apparatus
GB972191A (en) * 1960-03-08 1964-10-07 Siemens Ag A source of ions
US3216652A (en) * 1962-09-10 1965-11-09 Hughes Aircraft Co Ionic vacuum pump

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3881132A (en) * 1971-08-19 1975-04-29 California Inst Of Techn Compact, high intensity arc lamp with internal magnetic field producing means
DE3038575A1 (de) * 1980-10-13 1982-04-22 Sergej Ivanovič Tomsk Beljuk Elektronen-ionenquelle
EP0645947A1 (fr) * 1993-09-29 1995-03-29 Societe Anonyme D'etudes Et Realisations Nucleaires - Sodern Tube neutronique à confinement magnétique des électrons par aimants permanents et son procédé de fabrication
FR2710782A1 (fr) * 1993-09-29 1995-04-07 Sodern Tube neutronique à confinement magnétique des électrons par aimants permanents et son procédé de fabrication.
EP0660373A3 (en) * 1993-12-21 1996-11-20 Hughes Aircraft Co Punctual light source including a Xenon arc lamp.
CN101965094A (zh) * 2010-10-11 2011-02-02 长春致方达科技有限责任公司 一种球面靶陶瓷中子管及制造方法
CN102711355A (zh) * 2012-06-14 2012-10-03 东北师范大学 潘宁负离子源陶瓷中子管

Also Published As

Publication number Publication date
GB1083626A (en) 1967-09-20
CH446541A (de) 1967-11-15
DE1252814B (enrdf_load_stackoverflow)
NL143727B (nl) 1974-10-15
NL6504935A (enrdf_load_stackoverflow) 1966-10-18

Similar Documents

Publication Publication Date Title
US2456474A (en) Electric discharge device
GB698005A (en) Improvements in or relating to electron discharge devices
US2212206A (en) Electron device
US3100260A (en) Electron lens for reduction of spherical aberration
US3944873A (en) Hollow cathode type ion source system including anode screen electrodes
GB1594465A (en) Electron beam apparatus
US3408526A (en) Ion source having an annular permanent magnet
US2883580A (en) Pulsed ion source
GB806787A (en) Improvements in or relating to the production of a high plasma density in the anode region of a low pressure gas discharge
US3887830A (en) Cathode ray tube with magnetic beam alignment means
US3025429A (en) Ion magnetron
GB828224A (en) High-compression beam generating system for velocity-modulated tubes
US3448315A (en) Ion gun improvements for operation in the micron pressure range and utilizing a diffuse discharge
US2596508A (en) Electron gun for cathode-ray tubes
US2842703A (en) Electron gun for beam-type tubes
US2271666A (en) Controlled electrical discharge device
JPH08306329A (ja) 高磁束密度イオン源
GB1039884A (en) Improvements in or relating to gettering arrangements in velocity modulated electrontubes
US3522469A (en) Magnetic beam focusing structure for a traveling wave tube employing magnetic shunts between the pole pieces and the emitter
US2967943A (en) Gaseous discharge device
US3914637A (en) Method and apparatus for focusing an electron beam
GB451724A (en) Improvement in electric oscillation generator
US2723362A (en) Electron gun of the ion trap type
US2611878A (en) Particle source
GB728900A (en) Improvements in or relating to electron gun structures for use in cathode ray tubes