EP0362945A1 - Einrichtung zur Verbesserung der Penning-Ionenquelle in einer Neutronenröhre - Google Patents

Einrichtung zur Verbesserung der Penning-Ionenquelle in einer Neutronenröhre Download PDF

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Publication number
EP0362945A1
EP0362945A1 EP89202463A EP89202463A EP0362945A1 EP 0362945 A1 EP0362945 A1 EP 0362945A1 EP 89202463 A EP89202463 A EP 89202463A EP 89202463 A EP89202463 A EP 89202463A EP 0362945 A1 EP0362945 A1 EP 0362945A1
Authority
EP
European Patent Office
Prior art keywords
anode
ion source
field
magnetic field
ion
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.)
Withdrawn
Application number
EP89202463A
Other languages
English (en)
French (fr)
Inventor
Henri Bernardet
Xavier Godechot
Claude Lejeune
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.)
SODERN SA
Koninklijke Philips NV
Original Assignee
SODERN SA
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
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 SODERN SA, Philips Gloeilampenfabrieken NV, Koninklijke Philips Electronics NV filed Critical SODERN SA
Publication of EP0362945A1 publication Critical patent/EP0362945A1/de
Withdrawn legal-status Critical Current

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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
    • H05H3/00—Production or acceleration of neutral particle beams, e.g. molecular or atomic beams
    • H05H3/06—Generating neutron beams
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J27/00—Ion beam tubes
    • H01J27/02—Ion sources; Ion guns
    • H01J27/04—Ion sources; Ion guns using reflex discharge, e.g. Penning ion sources

Definitions

  • the invention relates to a Penning-type ion source device for a high flux sealed neutron tube in which said ion source with two electrodes (anode and cathode) forms an ionized gas channeled by a magnetic confinement field created by magnets or by any other means of creating said field and from which a high energy ion beam is projected onto a target electrode by means of an extraction and acceleration device to produce there a fusion reaction causing a neutron emission.
  • Neutron tubes of the same kind are used in the techniques of examination of matter by fast, thermal, epithermal or cold neutrons: neutronography, analysis by activation, analysis by spectrometry of inelastic scatterings or radiative captures, scattering of neutrons etc. .
  • the d (3 H , 4 He ) n fusion reaction delivering 14 MeV neutrons is usually the most used due to its large cross section for relatively low ion energies.
  • the number of neutrons obtained per unit of charge passing through the beam is always increasing as the energy of the ions directed towards a thick target is itself increasing and this largely at the beyond the energies of the ions obtained in the sealed tubes currently available and supplied by a THT not exceeding 250 kV.
  • the erosion of the target by ion bombardment is one of the most determining.
  • Erosion is a function of the chemical nature and structure of the target on the one hand, the energy of the incident ions and their density distribution profile on the impact surface on the other.
  • the target consists of a hydrurable material (Titanium, Scandium, Zirconium, Erbium etc ...) capable of fixing and releasing large quantities of hydrogen without significant disturbance of its mechanical strength; the total quantity set is a function of the target temperature and the hydrogen pressure in the tube.
  • the target materials used are deposited in the form of thin layers, the thickness of which is limited by problems of adhesion of the layer to its support.
  • One way to delay erosion of the target is, for example, to form the absorbent active layer from a stack of identical layers isolated from each other by a diffusion barrier. The thickness of each of the active layers is of the order of the depth of penetration of the deuterium ions coming to strike the target.
  • Another way of protecting the target and therefore of increasing the lifetime of the tube consists in acting on the ion beam so as to improve its density distribution profile on the impact surface. At a constant total ion current on the target electrode, which results in a constant neutron emission, this improvement will result from a distribution as uniform as possible of the current density over the whole of the surface offered by the target for bombardment. ions.
  • the ions are generally supplied by a Penning type ion source which has the advantage of being robust, of being cold cathode (hence a long service life), of give large discharge currents for low pressures (of the order of 10 A / torr), to have a high extraction efficiency (from 20 to 40%) and to be of small dimensions.
  • this type of source has the drawback of requiring a magnetic field of the order of a thousand gauss which introduces a significant inhomogeneity of density of the current of the ions inside the discharge and at the level of the emission zone. ions.
  • the object of the invention is to make the ion density more homogeneous at the emission level by modifying the Penning structure according to the prior art.
  • said magnetic field is made more divergent in the direction of the ion emission zone, by action on said magnets or on any other means of creating said field, modifying the confinement of ionizing electrons of the discharge and therefore of the ionization which results therefrom, being compensated by the adaptation of the shape and / or of the dimensions and / or of the positioning of the anode in said ion source.
  • the anode is of frustoconical shape with the largest diameter on the side of the low values of the magnetic field to take account of the divergence of the lines of force towards the zone of emission of the ions.
  • the circular anode is reduced in height and brought closer to the cathode in the zone of strong gradient of the magnetic field.
  • FIG. 1 shows the main basic elements of a sealed neutron tube 11 containing a gaseous mixture under low pressure to be ionized such as deuterium-tritium and which comprises an ion source 1 and an acceleration electrode 2 between which there is a very high potential difference allowing the extraction and acceleration of the ion beam 3 and its projection on the target 4 where the fusion reaction takes place resulting in the emission of neutrons at 14 MeV for example.
  • a sealed neutron tube 11 containing a gaseous mixture under low pressure to be ionized such as deuterium-tritium and which comprises an ion source 1 and an acceleration electrode 2 between which there is a very high potential difference allowing the extraction and acceleration of the ion beam 3 and its projection on the target 4 where the fusion reaction takes place resulting in the emission of neutrons at 14 MeV for example.
  • the ion source 1 secured to an insulator 5 for the passage of the THT supply connector is a Penning type source for example, consisting of a cylindrical anode 6, of a cathode structure 7 to which is incorporated a magnet 8 with an axial magnetic field which confines the ionized gas 9 around the axis of the anode cylinder and whose lines of force 10 show a certain divergence.
  • An ion emission channel 12 is formed in said cathode structure opposite the anode.
  • the cylindrical anode 6 is brought to a higher potential of the order of 4 kV than that of the cathode 7 itself brought to a very high voltage of 250 kV for example.
  • the set of magnets 8 provides a large magnetic field of the order of a thousand gauss.
  • the ions are extracted from the emission channel 12 formed in the cathode thus playing the role of emission electrode, by means of the acceleration electrode 2 carried as well as the target electrode 4 at the potential 0 of the mass.
  • the idea of the invention consists in modifying the confinement of the ionized gas by acting on the arrangement of the magnets of the assembly 8 so that the magnetic field be more divergent.
  • the reduction in the discharge current which results therefrom can be advantageously compensated by means of the solutions in FIGS. 3 and 4.
  • the circular anode has been replaced by a frustoconical anode 13 whose generators tend to follow the lines of force of the magnetic field 10.
  • the ionized gas 9 is more spread due to said modification of the confinement.
  • the diameters of the frustoconical anode must be increased in order to avoid the interception of the electrons.
  • the circular anode 14 is reduced in height and offset towards the strong field zone near the upper part of the cathode so as to always avoid the interception of the electrons.
EP89202463A 1988-10-07 1989-10-02 Einrichtung zur Verbesserung der Penning-Ionenquelle in einer Neutronenröhre Withdrawn EP0362945A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8813185A FR2637724B1 (fr) 1988-10-07 1988-10-07 Dispositif de perfectionnement de la source d'ions de type penning dans un tube neutronique
FR8813185 1988-10-07

Publications (1)

Publication Number Publication Date
EP0362945A1 true EP0362945A1 (de) 1990-04-11

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP89202463A Withdrawn EP0362945A1 (de) 1988-10-07 1989-10-02 Einrichtung zur Verbesserung der Penning-Ionenquelle in einer Neutronenröhre

Country Status (4)

Country Link
US (1) US5104610A (de)
EP (1) EP0362945A1 (de)
JP (1) JPH02148699A (de)
FR (1) FR2637724B1 (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2666477A1 (fr) * 1990-08-31 1992-03-06 Sodern Tube neutronique a flux eleve.
US6441569B1 (en) 1998-12-09 2002-08-27 Edward F. Janzow Particle accelerator for inducing contained particle collisions
US10408968B2 (en) 2013-12-31 2019-09-10 Halliburton Energy Services, Inc. Field emission ion source neutron generator
US9756714B2 (en) 2013-12-31 2017-09-05 Halliburton Energy Services, Inc. Nano-emitter ion source neutron generator
MX361393B (es) 2013-12-31 2018-12-05 Halliburton Energy Services Inc Generador de neutrones de tritio-tritio y método de registro.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2806161A (en) * 1952-07-08 1957-09-10 Jr John S Foster Coasting arc ion source
LU46217A1 (de) * 1963-06-12 1964-08-01

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3546513A (en) * 1968-03-11 1970-12-08 Us Air Force High yield ion source
US4714834A (en) * 1984-05-09 1987-12-22 Atomic Energy Of Canada, Limited Method and apparatus for generating ion beams
YU46728B (sh) * 1986-10-23 1994-04-05 VUJO dr. MILJEVIĆ Jonsko-elektronski izvor sa šupljom anodom

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2806161A (en) * 1952-07-08 1957-09-10 Jr John S Foster Coasting arc ion source
LU46217A1 (de) * 1963-06-12 1964-08-01

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PULSED NEUTRON RESEARCH, PROC. SYMP., Karslruhe, vol. II, 10-14 mai 1965, pages 609-622; C.W. ELENGA et al.: "The generation of neutron pulses and modulated neutron fluxes with sealed-off neutron tubes" *
REVUE DE PHYSIQUE APPLIQUEE, vol. 12, no. 12, décembre 1977, pages 1835-1848; C. LEJEUNE et al.: "Multiduoplasmatron et multiduopigatorn: sources de plasma uniforme pour la formation de faisceaux d'ions multiamperes *

Also Published As

Publication number Publication date
US5104610A (en) 1992-04-14
FR2637724B1 (fr) 1990-12-28
FR2637724A1 (fr) 1990-04-13
JPH02148699A (ja) 1990-06-07

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