CN102709139B - Field emission ion source for outputting monatomic hydrogen ion beam - Google Patents
Field emission ion source for outputting monatomic hydrogen ion beam Download PDFInfo
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- CN102709139B CN102709139B CN201210161962.6A CN201210161962A CN102709139B CN 102709139 B CN102709139 B CN 102709139B CN 201210161962 A CN201210161962 A CN 201210161962A CN 102709139 B CN102709139 B CN 102709139B
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- field emission
- foam metal
- ion source
- emission array
- active thin
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Abstract
The invention provides a field emission ion source for outputting a monatomic hydrogen ion beam, belonging to the technical field of a small specific ion source. The field emission ion source mainly comprises a field emission array, a foam metal active thin board and an acceleration electrode. The foam metal active thin board is placed on the field emission array after being isolated through an insulating material; the surface of the foam metal active thin board is parallel to the surface of the field emission array; and the acceleration electrode is placed on the foam metal active thin board. When the field emission ion source works, the working voltage of the field emission array is less than 1kV, so that the electric field on a tip surface is 15-20V/nm. The foam metal active thin board is externally connected with low-voltage power supply about minus 700V relative to the upper surface of the field emission array, and the acceleration electrode is externally connected with high-voltage pulse power supply more than minus 10kV relative to the foam metal active thin board. With the adoption of the field emission ion source provided by the invention, the hydrogen (including isotopic deuterium or tritium) atomic ion beam with a high ratio can be output from the acceleration electrode, the working voltage of the field emission array is reduced, so that the field emission array is prevented from being burnt.
Description
Technical field
The present invention relates to a kind of emission ion source, particularly a kind of field emission ion source that is exclusively used in output mon-H ion beam, belongs to small-sized, special technology of ion source field.
Background technology
Neutron tube is a kind of neutron source of safe and portable, and compared with common isotope neutron source, its power spectrum monochromaticjty is good, and without γ background and can produce pulsed neutron, the used time can not turn-off, thus protection easily, storage administration and convenient transportation.Neutron tube is all integrated in ion source, accelerator, target and pressure regulation system in a sealed tube, when work without vaccum-pumping equipment and compressed air source unit.Neutron tube can be widely used in defence engineering and work, agriculture, doctor field, particularly military project and safety inspection field.Use in the wild neutron tube time, the portability of neutron tube seems even more important, but it is all bulky much to have at present the neutron source of high yield, can only in laboratory, move.
The neutron yield of neutron tube is with wherein critical component--it is monatomic relevant with the ratio of molecular deuterium ions that deuterium ion source produces, under same accelerating voltage and beam current density, the monatomic deuterium ion ratio that ion source produces is higher, neutron yield is just larger, that is to say, the sensitivity of detection and efficiency are also higher.For example, a branch of containing 50%D
+and 50%D
2 +the neutron yield ratio 100%D that obtains with 100 KeV energy bombardments tritium targets of ion beam
+the neutron yield that bundle obtains under same bombarding conditions is low by 48%, i.e. D under this condition
2 +ion does not almost have and tritium target generation nuclear reaction.The ion source of neutron tube is substantially all based on gas discharge principle at present, and as penning source, radio-frequency ion source etc., wherein penning source accounts for leading.The advantages such as that Penning ion source has is simple in structure, operating air pressure is low, electric power system is simple, reliable operation, but monatomic ion proportion that its ionization produces is very low, and for example certain penning source is operated in 2 × 10
-1pa H
2when air pressure, discharging current are 2 A, the H of output
+: H
2 +: H
3 +=1:1.7:6.3.To obtain in the case high yield neutron, the high line Ions Bombardment target that penning source must be exported, but this cause again ion sputtering and secondary phenomenon serious, reason is by H
2 +the yield of the metal surface secondary electron causing is almost two times of secondary electron that under same energy, proton causes.
Because current various ion sources cannot meet the demand of high monatomic ion yield and neutron tube (and accessory) miniaturization simultaneously, the U.S. took the lead in using the field emission ion source of direct current pulse power source for neutron tube in 2005.Document (B.B. Johnson, P.R. Schwoebel, C.E. Holland, P.J. Resnick, K.L. Hertz, D.L. Chichester, Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment 663/1 (2012) 64; P.R. Schwoebel, Applied Physics Letters 87/5 (2005) and A. Persaud, I. Allen, M.R. Dickinson, T. Schenkel, R. Kapadia, K. Takei, A. Javey, Journal of Vacuum Science & Technology B 29/2 (2011)) the field emission ion source for neutron tube announced structure as shown in Figure 1, by substrate (5), pointed cone array (6), insulating barrier (7), perforate grid (8) and tritium target (9) formation.The general principle of emission ion source is like this, and it is to utilize extremely sharp keen tip to obtain very high electric field strength, thus make gas molecule ionization or from tip end surface the form desorption with ion, thereby form emission of ions.Research finds that tip end surface electric field strength is higher, and the ratio of transmitting atomic deuterium ion is just larger.In the time that most advanced and sophisticated electric field strength reaches 30 V/nm, most advanced and sophisticated transmitting H
+, H
2 +ratio is about 4:1, thereby neutron tube prepared by use emission ion source can obtain higher neutron yield, and drives because field emission ion source adopts relatively simple DC power supply, very practical.
Being in operation when for neutron tube of emission ion source also there will be a large problem at present: field emission array is in the time of operation, when reaching sufficient intensity (30 V/nm), emission tip electric field makes atomic ion transmitting time, the electric field strength of gate surface also causes grid divergent bundle bombardment pointed cone, causes pointed cone large area to be burnt.This problem is fatal for the ion source long-term safety service requirement of neutron tube.
Object of the present invention will solve an emission ion source exactly after heightening voltage and reaching height ratio hydrogen atom ion output and require, bombard the problem of easily burning because the high electric field strength in tip causes grid electron emission, make an emission ion source steady operation and can launch height ratio hydrogen atom ion beam.Addressing this problem the method generally adopting is abroad to improve the smooth degree of gate surface, thereby the electron emission of suppressor grid suppresses the bombardment of duplet field emission array.
Summary of the invention
For overcoming the above problems, the present invention has increased an active metal in a tradition emission ion source.The effect of active metal is to make molecular ion beam under catalytic action, be cracked into atomic ion beam transmitting, has reduced like this applied electric field intensity of field emission array, makes it under the safety electric field intensity of 15 ~ 20 V/nm, launch hydrogen molecular ion.When these molecular ions pass through active metal, because making molecular ion, catalytic action is decomposed into atomic ion transmitting.Use after this improved ion source, both improved the yield of neutron tube, the working life that can extend again field emission array.
Of the present invention a kind of for exporting the field emission ion source of mon-H ion beam, its structure as shown in Figure 2, comprise field emission array, it is characterized in that, also comprise the active thin plate of a foam metal and intensifying ring, the active thin plate of described foam metal is positioned on field emission array after isolating by an insulating material, and its surface is parallel with field emission array surface; Described intensifying ring is placed on the active thin plate of foam metal.
Further, above-mentioned for exporting the field emission ion source of mon-H ion beam, it is characterized in that described field emission array comprises carbon nano-tube field emission array, metal pointed cone field emission array or silicon tip cone field emission array.
Further, above-mentioned for exporting the field emission ion source of mon-H ion beam, it is characterized in that the material of the active thin plate of described foam metal is Fe, Co, Ni or Ti.
Further, above-mentioned for exporting the field emission ion source of mon-H ion beam, it is characterized in that described foam metal active gauge of sheet≤10 mm, average pore size>=0.2 mm, specific area>=250 m
2/ m
3.
When work, the operating voltage of adjusting field emission array makes tip end surface electric field in 15 ~ 20 V/nm.The active thin plate of foam metal is with respect to the low-tension supply of external-700 V left and right of the upper surface of field emission array, and intensifying ring is with respect to high-voltage pulse power sources more than external-10 kV of the active thin plate of foam metal.Adopt ion source of the present invention to export height ratio hydrogen (comprising its isotope deuterium or tritium) atomic ion beam from intensifying ring, and reduce field emission array operating voltage and protect it to be unlikely to burn.
Brief description of the drawings
Existing emission ion source cross-sectional view of Fig. 1.
Fig. 2 is of the present invention for exporting the field emission ion source cross-sectional view of mon-H ion beam.
Wherein, the mark implication of each accompanying drawing is:
1-field emission array, 2-insulating material, the active thin plate of 3-foam metal, 4-intensifying ring, 5-substrate, 6-pointed cone array, 7-insulating barrier, 8-perforate grid and 9-tritium target.
Embodiment
Below in conjunction with embodiment and accompanying drawing 2, the present invention is described in further detail.
Embodiment mono-:
As shown in Figure 2, on metal pointed cone field emission array 1, place the active thin plate 3 of a Ni foam metal with insulating material 2 isolation that 1 mm is thick, its thickness is 2 mm, average pore size=0.23 mm, specific area=5800 m
2/ m
3; Another also have an intensifying ring 4 to be placed on the active thin plate 3 of Ni foam metal.In deuterium gas atmosphere, connect external power supply and start this ion source, due to the catalytic action of the active thin plate 3 of Ni foam metal, the deuterium molecule ion that metal pointed cone field emission array 1 is launched can be transformed into D-atom ion, available omegatron mass spectrometer test D-atom and molecular ion beam ratio after intensifying ring 4 accelerates.Start after field emission array, the active thin plate 3 of Ni foam metal is with respect to the low-tension supply of external-700 V left and right of the upper surface of field emission array 1, and intensifying ring 4 is with respect to high-voltage pulse power sources more than external-10 kV of the active thin plate 3 of Ni foam metal.During without the active thin plate 3 of Ni foam metal, the ratio of output D-atom and molecular ion ion beam is 1:99, and the ratio that adds the active rear D-atom of thin plate 3 of Ni foam metal and molecular ion beam becomes 1:0.6.
Embodiment bis-:
As shown in Figure 2, on silicon tip cone field emission array 1, place the active thin plate 3 of a Fe foam metal with insulating material 2 isolation that 1 mm is thick, its thickness is 3 mm, average pore size=0.7 mm, specific area=1580 m
2/ m
3; Another also have an intensifying ring 4 to be placed on the active thin plate 3 of Fe foam metal.In deuterium gas atmosphere, connect external power supply and start this ion source, due to the catalytic action of the active thin plate 3 of Fe foam metal, the deuterium molecule ion that silicon tip cone field emission array 1 is launched can be transformed into D-atom ion, available omegatron mass spectrometer test D-atom and molecular ion beam ratio after intensifying ring 4 accelerates.Start after field emission array, the active thin plate 3 of Fe foam metal is with respect to the low-tension supply of external-700 V left and right of the upper surface of field emission array 1, and intensifying ring 4 is with respect to high-voltage pulse power sources more than external-10 kV of the active thin plate 3 of Fe foam metal.During without the active thin plate 3 of Fe foam metal, the ratio that records output D-atom and molecular ion ion beam is 1:99, and the ratio that adds the active rear D-atom of thin plate 3 of Fe foam metal and molecular ion beam becomes 1:1.
Embodiment tri-:
As shown in Figure 2, on carbon nano-tube field emission array 1, place the active thin plate 3 of a Co foam metal with insulating material 2 isolation that 1 mm is thick, its thickness is 8 mm, average pore size=1.6 mm, specific area=250 m
2/ m
3; Another also have an intensifying ring 4 to be placed on the active thin plate 3 of Co foam metal.In deuterium gas atmosphere, connect external power supply and start this ion source, due to the catalytic action of the active thin plate 3 of Co foam metal, the deuterium molecule ion that carbon nano-tube field emission array field emission array 1 is launched can be transformed into D-atom ion, available omegatron mass spectrometer test D-atom and molecular ion beam ratio after intensifying ring 4 accelerates.Start after carbon nano-tube field emission array 1, the active thin plate 3 of Co foam metal is with respect to the low-tension supply of external-700 V left and right of the upper surface of field emission array, and intensifying ring 4 is with respect to high-voltage pulse power sources more than external-10 kV of the active thin plate 3 of Co foam metal.During without the active thin plate 3 of Co foam metal, the ratio that records output D-atom and molecular ion ion beam is 1:99, and the ratio that adds the active rear D-atom of thin plate 3 of Co foam metal and molecular ion beam becomes 1:1.5.
Embodiment tetra-:
As shown in Figure 2, on carbon nano-tube field emission array 1, place the active thin plate 3 of a Ti foam metal with insulating material 2 isolation that 1 mm is thick, its thickness is 5 mm, average pore size=0.95 mm, specific area=500 m
2/ m
3; Another also have an intensifying ring 4 to be placed on the active thin plate 3 of Ti foam metal.In deuterium gas atmosphere, connect external power supply and start this ion source, due to the catalytic action of the active thin plate 3 of Ti foam metal, the deuterium molecule ion that carbon nano-tube field emission array field emission array 1 is launched can be transformed into D-atom ion, available omegatron mass spectrometer test D-atom and molecular ion beam ratio after intensifying ring 4 accelerates.Start after field emission array, the active thin plate 3 of Ti foam metal is with respect to the low-tension supply of external-700 V left and right of the upper surface of carbon nano-tube field emission array 1, and intensifying ring 4 is with respect to high-voltage pulse power sources more than external-10 kV of the active thin plate 3 of Ti foam metal.During without Ti foam metal active board 3, the ratio that records output D-atom and molecular ion ion beam is 1:99, and the ratio that adds Ti foam metal active board 3 rear D-atoms and molecular ion beam becomes 1:1.5.
Claims (4)
- One kind for export mon-H ion beam field emission ion source, comprise field emission array (1), it is characterized in that, also comprise a foam metal active thin plate (3) and intensifying ring (4), after the active thin plate of described foam metal (3) is isolated by an insulating material (2), be positioned on field emission array (1), its surface is parallel with field emission array surface, and described intensifying ring (4) is placed on the active thin plate of foam metal.
- 2. according to claim 1ly it is characterized in that for exporting the field emission ion source of mon-H ion beam, described field emission array (1) can be carbon nano-tube field emission array, metal pointed cone field emission array or silicon tip cone field emission array.
- 3. according to claim 1ly it is characterized in that for exporting the field emission ion source of mon-H ion beam, the material of the active thin plate of described foam metal (3) is Fe, Co, Ni or Ti.
- 4. according to claim 1 for exporting the field emission ion source of mon-H ion beam, it is characterized in that thickness≤10 mm, average pore size>=0.23 mm, specific area>=250 m of the active thin plate of described foam metal (3) 2/ m 3.
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|---|---|---|---|
| CN201210161962.6A CN102709139B (en) | 2012-05-23 | 2012-05-23 | Field emission ion source for outputting monatomic hydrogen ion beam |
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|---|---|---|---|
| CN201210161962.6A CN102709139B (en) | 2012-05-23 | 2012-05-23 | Field emission ion source for outputting monatomic hydrogen ion beam |
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|---|---|
| CN102709139A CN102709139A (en) | 2012-10-03 |
| CN102709139B true CN102709139B (en) | 2014-09-17 |
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| CN104332375B (en) * | 2014-09-05 | 2016-12-28 | 西安奥华电子仪器股份有限公司 | Ion source digital IIR filters parameter self-tuning system and method |
| CN106841706B (en) * | 2017-03-31 | 2023-06-27 | 中国工程物理研究院电子工程研究所 | Ion source test fixture |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1265230A (en) * | 1997-07-22 | 2000-08-30 | 布莱克光电有限公司 | Inorganic hydrogen compounds, separation methods, and fuel applications |
| CN202721105U (en) * | 2012-05-23 | 2013-02-06 | 四川大学 | Field emission ion source used for outputting monatomic hydrogen ion beam |
-
2012
- 2012-05-23 CN CN201210161962.6A patent/CN102709139B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1265230A (en) * | 1997-07-22 | 2000-08-30 | 布莱克光电有限公司 | Inorganic hydrogen compounds, separation methods, and fuel applications |
| CN202721105U (en) * | 2012-05-23 | 2013-02-06 | 四川大学 | Field emission ion source used for outputting monatomic hydrogen ion beam |
Non-Patent Citations (4)
| Title |
|---|
| B.Bargsten Johnson.etc.Field ion source development for neutron generators.《Nuclear Instruments and Methods in》.2012,第64-74页. |
| Field desorption ion source development for neutron generators;I.Solano.etc;《Nuclear Instruments and Methods in》;20080311;第76-81页 * |
| Field ion source development for neutron generators;B.Bargsten Johnson.etc;《Nuclear Instruments and Methods in》;20120121;第64-74页 * |
| I.Solano.etc.Field desorption ion source development for neutron generators.《Nuclear Instruments and Methods in》.2008,第76-81页. |
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