CN1300093A - Hard X-ray image intensifier - Google Patents
Hard X-ray image intensifier Download PDFInfo
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- CN1300093A CN1300093A CN 99115936 CN99115936A CN1300093A CN 1300093 A CN1300093 A CN 1300093A CN 99115936 CN99115936 CN 99115936 CN 99115936 A CN99115936 A CN 99115936A CN 1300093 A CN1300093 A CN 1300093A
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- image intensifier
- ray
- photocathode
- emission layer
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- 239000000463 material Substances 0.000 claims description 33
- 238000001704 evaporation Methods 0.000 claims description 19
- 230000008020 evaporation Effects 0.000 claims description 19
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 10
- 239000000758 substrate Substances 0.000 claims description 10
- 229910052792 caesium Inorganic materials 0.000 claims description 9
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 claims description 9
- 238000007747 plating Methods 0.000 claims description 8
- 229910052759 nickel Inorganic materials 0.000 claims description 7
- 230000004913 activation Effects 0.000 claims description 2
- 150000004820 halides Chemical class 0.000 claims description 2
- 150000004678 hydrides Chemical class 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 abstract description 12
- 239000004411 aluminium Substances 0.000 description 6
- 229910052782 aluminium Inorganic materials 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 6
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M potassium chloride Inorganic materials [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 5
- 239000010949 copper Substances 0.000 description 5
- 238000001771 vacuum deposition Methods 0.000 description 5
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 4
- 229910000952 Be alloy Inorganic materials 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 150000002681 magnesium compounds Chemical class 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- OWXLRKWPEIAGAT-UHFFFAOYSA-N [Mg].[Cu] Chemical compound [Mg].[Cu] OWXLRKWPEIAGAT-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000008676 import Effects 0.000 description 2
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 229910001508 alkali metal halide Inorganic materials 0.000 description 1
- 150000008045 alkali metal halides Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- SIAPCJWMELPYOE-UHFFFAOYSA-N lithium hydride Chemical compound [LiH] SIAPCJWMELPYOE-UHFFFAOYSA-N 0.000 description 1
- 229910000103 lithium hydride Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
Landscapes
- Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
Abstract
A hard X-ray image intensifier is composed of substrate-X-ray photoelectric cathode structure consisting of X-ray absorbing and emitting layer and Auger electron emitting layer, which is csI evaporated layer with 400-600A thickness, Auger electron emitting layer with 500-1000A thickness and single-or multi-layer structure without microchannel plate, and features high conversion efficiency, high S/N ratio and good background, adjustable output brightness, high finished product rate and low cost.
Description
The present invention is the improvement to X ray image intensifier structure, belongs to the radiodiagnosis technical field.
At present a lot of for the research of X ray image intensifier and improved report and patent, mainly be the improvement of electron-optical system, conversion screen being made system method and aspects such as material and output phosphor screen, the improvement of target assembly is then seldom.The existing open source information of structure of relevant X ray image intensifier cathode assembly has three types.First kind is the structure of cathode substrate-conversion screen-cathode conductive layer-visible light photocathode; As the CN97108608.7 patent application, this structure is because the existence of conversion screen, makes conversion efficiency not high (about 10%); Simultaneously because conversion screen (as CsI (Na) screen) is that the similar fibre-optic light-pipe structure that relies on crystal growth to form improves the transmittability of light and the spatial resolution of image, have the light pipe defective inevitably and exist, this has just brought the shortcoming not fogging, that background noise is big; And conversion screen (thick 300-500 μ m) forms by crystal growth fully, and not only complex process, and cost is very high; For the lateral resistance that reduces visible light photocathode surface, prevent image retention, between conversion screen and photocathode, be manufactured with conductive layer, make technology complicated more; The rate of finished products of this structure homogeneous tube is the highest has only 30%.Second kind is that the field helps X ray photocathode structure, help the structure of electrode as conductive substrates among the CNZL93119245.5-X ray photocathode-field, wherein photocathode adopts low/highdensity alkali metal halide, is the vacuum evaporation layer of 500-800 μ m thickness, cost of manufacture height; And conductive substrates and field help the manufacture craft of electrode more complicated, the more important thing is the image intensifier conversion efficiency of this structure, must use microchannel plate is arranged, not only noise is big, background subtraction, and manufactured size is subject to the size of microchannel plate, can not make larger sized image intensifier, the homogeneous tube of this structure still has low, the defect of high cost of rate of finished products simultaneously.The third is the structure of the substrate-photocathode in the grenz ray photocathode, its photocathode is CsI evaporation layer (thick about 500 μ m), it is only applicable to low-energy grenz ray, because transfer ratio is low, also must use microchannel plate, so not only the scope of application is little for it, and have that noise is big, background subtraction, shortcoming that cost is high.Also disclose the structure of substrate-photocathode among the CNZL93104172.4, by analyzing in the disclosed content, it can be applicable to the hard X ray scope, but and the structure and material of unexposed its photocathode, and the setting of microchannel plate is arranged, noise is big so it has at least, background subtraction, defect of high cost.In addition, owing to employing has into caesium processing to the visible light photocathode in the prior art, and can not expose atmosphere before the tubulature, and free active atom is induced one, very easily cause spark phenomenon between the interior electrode of pipe.In a word, existing X ray image intensifier ubiquity has that conversion efficiency is low, noise is big, background subtraction, brightness are non-adjustable, complex structure, technological requirement height, low, the defect of high cost of rate of finished products.
The objective of the invention is the photocathode structure of X ray image intensifier is improved, make it to become hard X ray (ray energy is greater than 12.4Kev) photocathode, the hard X-ray image intensifier of being manufactured has the conversion efficiency height, noise is little, background good, simple in structure, make easily, rate of finished products is high, cost is low advantage, and its method for production is proposed.Another object of the present invention is to design the hard X-ray image intensifier of adjustable brightness.
For achieving the above object, technical scheme of the present invention is to be done in such a manner.Designed hard X-ray image intensifier, the cathode assembly of employing substrate-X ray photocathode structure; Wherein the X ray photocathode absorbs emission layer and Auger (Auger) electron emission layer formation by X ray, absorb emission layer near the substrate setting, be thick CsI of 400-600 or the evaporation layer of PbI, auger electrons emission bed thickness 500-1000 , be arranged on the absorbed layer surface, low-density evaporation layer for single or multiple lift can accompany high density evaporation layer between multilayer; Be not provided with microchannel plate in the described image intensifier.Wherein absorbing emission layer selects for use low-density evaporation layer more a little than highdensity better effects if.The used material of auger electrons emission layer is an atomic number less than halide, oxide, the hydride of 35 light element; When making, can select for use wherein a kind of to be material, also can select for use wherein several to be coated with respectively or several mixing is coated with.
Feature of the present invention also is, closely being sticked in cathode assembly photocathode one side is equipped with the secondary net, and as photoelectron Secondary Emission electrode, the gap of net and photocathode is 1-2mm, mesh density is 6-70 lattice/mm, is principle with the spatial resolution that does not influence image intensifier; And the net the surface be shaped on secondary electron emission layer.The photoelectron that the nearly secondary net that pastes can make photocathode launch obtains multiplication, and make the output adjustable brightness of image intensifier by the adjustment of voltage difference between photocathode and net, and mesh density is that its density of high request is big more more with the image intensifier spatial resolution.Described secondary net can be selected nickel-clad copper net or nickel plating stainless (steel) wire for use, and nickel plating is the adhesive force that plates secondary emission material in order to improve, and online secondary electron emission layer is the thick secondary electron emission material evaporation layer of 800-1400 .
Feature of the present invention also is, described auger electrons emission layer can be manufactured by superlattice structure, promptly adopt multiple material to replace the evaporation tens layers up to satisfying its thickness requirement, and the thick average free layer thickness that is no more than its material of each layer, usually in 10-30 scope.No matter described auger electrons emission layer is superlattice structure, or the low density structures of single or multiple lift, and accompany highdensity structure between the multilayer low-density, can carry out the caesium that advances of cathode activation handles, promptly under vacuum is heated condition, photocathode is advanced caesium and handle, to improve the auger electrons emission ratio.The photocathode that advances after caesium is handled can be exposed to atmosphere, and this is beneficial to the homogeneous tube that is assembled.
Owing to adopt the designed hard X ray photocathode of the present invention, then make the performance of prepared hard X-ray image intensifier obtain very big improvement.Not only materials are few in the making of photocathode, technology is simple, production cycle shortenings, rate of finished products height, production cost reduction, and improved quantum efficiency greatly, can reach 60-140%, thereby improved the signal to noise ratio of image intensifier, also saved the setting of microchannel plate, the making of large scale image intensifier is not limited; Because advancing, photocathode can be exposed to atmosphere after caesium is handled, so not introducing of free active atom, so fundamentally eliminated in the pipe phenomenon that sparking and background degenerate between each electrode, thereby the contrast of having improved homogeneous tube greatly (through the test of sample pipe, adds each pole tension during not according to X ray, makes anode voltage add to 25KV, cutout screen is not luminous fully, noiseless source in the witness tube does not have spark phenomenon yet between each electrode), this rate of finished products, reduction background advantageous particularly to improving homogeneous tube; Again owing to behind photocathode, closely post the secondary net, can not only make photoelectron obtain multiplication, improve conversion efficiency, and make the adjustable brightness of output image, also widened the scope (high energy adapts to the ray energy of 150Kev) of X ray energy changing; Owing to the time response of the X ray image intensifier of making by the present invention is fast, can reach the Ps magnitude, so it can be used for the high-speed photography of X ray.In a word, that the designed hard X-ray image intensifier of the present invention has is simple in structure, simplified manufacture craft, improved rate of finished products (〉 60%), reduce production cost (＞50%), and the performance of image intensifier is well improved, be fit to industrialized mass production.
Accompanying drawing 1 is the structural representation of the designed hard X-ray image intensifier of the present invention.1 is input window among the figure, and 2 is cathode assembly, and 3 is shell, and 4 is focusing electrode, and 5 is cutout screen, and 6 is anode, and 7 is (aluminium) substrate, and 8 is the X ray photocathode, and 9 is (the near subsides) secondary net.
Describe embodiment and the requirement thereof of technical solution of the present invention in detail below in conjunction with accompanying drawing.
Each evaporation layer of the designed photocathode of the present invention uses vacuum coating equipment to finish, and the tight of each evaporation layer loosens Degree can be undertaken by narration operation among the CNZL93119245.5. Be difficult to control if each rete is coated with thickness with the time, then can Control with quantity of material. Selecting of auger electrons emissive layer materials can be by " surface and film analysis basis " (Yan Yan Translate, publishing house of Fudan University 1986 publishes) in narration, advance as principle take nontoxic, pollution-free, cheap Row is selected, and wherein useful atomic number is less than the record as the auger electrons emissive material of 35 light element. Superlattices Being produced in " Modern Physics progress " (open gift and compile, publishing house of Tsing-Hua University published in 1998) of structure has note Carry. The caesium processing of advancing of photocathode generally is used in the making of visible light photocathode, and just the present invention makes The X ray photocathode can be exposed to atmosphere after caesium is processed advancing, thereby make active free atom volatilization.
The designed secondary net of the present invention can select the string diameter of net in 4 μ m-50 mu m ranges, The ratio of string diameter and screen distance is 1: 2; The secondary electron emission layer that is coated with on the net also adopts vacuum coating equipment to finish, Secondary electron emission material then can be by " photoelectric device " (Shen Tang and volume, the People's Education Publishing House published in 1961) Middle narration is chosen, and can choose a kind of material and make, and also can choose multiple material and be coated with respectively, or many The mixing of planting material is coated with. Online secondary electron emission layer can be coated on the outside or the inboard of net, also can Be that both sides all are coated with, do not affect its effect, consider then to be produced on a side, this from the continuity of process for plating as far as possible Sample not only saved time, but also saving of labor.
Embodiment 1. is a material with CsI on the thick aluminium substrate of 0.3mm, be coated with the thick low-density X ray of 600 and absorb emission layer, be that material is coated with the thick low-density auger electrons emission layer of 800 then with KCl, just constituted the hard X ray photo cathode with this, can reach more than 80% with the quantum efficiency of the hard X-ray image intensifier of its making.Other gets the nickel plating copper mesh that Chengdu 773 factories produce, the thick 50 μ m in silk footpath, grid aperture 100 μ m are material with silver-colored magnesium compound and copper magnesium compound in vacuum coating equipment, mix being coated with the thick secondary electron emission layer of 1200 simultaneously, its secondary electron multiplication constant can reach 2-3 doubly.
Embodiment 2. is on the thick aluminium substrate of 0.3mm, with PbI is that material is coated with the thick high density X ray absorption emission layer of 400 , be that material mixes simultaneously and is coated with the thick low-density auger electrons emission layer of 800 then with KCl, LiF, MgO, with the hard X-ray image intensifier of its making, its quantum efficiency can reach more than 60%.Other gets the nickel plating copper mesh, the thick 30 μ m in silk footpath, and grid aperture 60 μ m are that material is coated with the thick secondary electron emission layer of 1000 with CsI and KCl in vacuum coating equipment, its secondary electron multiplication constant can reach 3-4 doubly.
Embodiment 3. is on the thick aluminium substrate of 0.3mm, with CsI is that material is coated with the thick low-density X ray absorption emission layer of 500 , be material then with LiF, NaCl, LiH, LiCl, KCl, be coated with low-density evaporation layer respectively, wherein LiH is a high density evaporation layer, form the thick auger electrons emission layer of 1000 , use it for the making hard X-ray image intensifier, its quantum efficiency can reach more than 100%.Other gets the nickel plating stainless (steel) wire of import, the thick 10 μ m in silk footpath, grid aperture 20 μ m are that material is coated with respectively with copper beryllium alloy, silver-colored magnesium compound, copper magnesium compound in vacuum coating equipment, form the thick secondary electron emission layer of 800A, its secondary electron multiplication constant can reach 3-4 doubly.
Embodiment 4. is that material is coated with the thick low-density X ray of 500 and absorbs emission layer with CsI on the thick aluminium substrate of 0.3mm; Then with LiF, Mg
2O
3, NaF is that material is coated with low-density evaporation layer respectively, forms the thick auger electrons emission layer of 800 , can reach more than 80% with the quantum efficiency of its hard X-ray image intensifier of making.
Embodiment 5. is that material is coated with the thick low-density X ray of 500 and absorbs emission layer with CsI on the thick aluminium substrate of 0.3mm; Be that material is coated with auger electrons emission layer (every bed thickness 20 ) by superlattice structure respectively then, be coated with so repeatedly 5 times, form the thick evaporation layer of 700 with LiF, BeO, KCl, NaF, LiH, LiCl, NaCl; Finish into caesium again and handle in the vacuum machine, the short time is exposed to atmosphere before tubulature then, can reach more than 140% with the quantum efficiency of the hard X-ray image intensifier of its making.
Embodiment 6. gets the nickel plating stainless (steel) wire of import, the thick 4 μ m in silk footpath, grid aperture 10 μ m are that material is coated with respectively with copper beryllium alloy, silver-colored magnesium compound nickel-beryllium alloy in the vacuum machine, form the thick secondary electron emission layer of 1400 , its secondary electron multiplication constant can reach 4-5 doubly.
Claims (6)
1. a hard X-ray image intensifier adopts the cathode assembly that substrate-X ray photocathode structure is arranged, and it is characterized in that, described X ray photocathode absorbs emission layer by X ray and the auger electrons emission layer constitutes; Absorbing emission layer is thick CsI of 400-600 or PbI evaporation layer, near the substrate setting; Auger electrons emission bed thickness 500-1000 is arranged on the absorbed layer surface, is individual layer or multilayer evaporation layer structure; Be not provided with microchannel plate in the described image intensifier.
2. image intensifier according to claim 1 is characterized in that, the evaporation layer that described auger electrons emission layer can be a superlattice structure also can be the low-density evaporation layer of individual layer or multilayer, can accompany high density evaporation layer between multilayer.
3. image intensifier according to claim 2 is characterized in that, closely being sticked in cathode assembly photocathode one side is equipped with the secondary net, as photoelectron Secondary Emission electrode; Mesh density is 6-70 lattice/mm; And the net the surface be shaped on secondary electron emission layer.
4. image intensifier according to claim 3 is characterized in that, described secondary net is selected the nickel plating wire netting for use, and online secondary electron emission layer is the thick secondary electron emission material evaporation layer of 800-1400 .
5. according to each described image intensifier among the claim 2-4, it is characterized in that, auger electrons emission layer material therefor is an atomic number less than halide, oxide, the hydride of 35 light element, can select wherein a kind of for material when manufacturing for use, also can select wherein several be coated with respectively or several mixing is coated with for use.
6. image intensifier according to claim 5 is characterized in that, the X ray photocathode of manufacturing also need carry out the caesium that advances of cathode activation to be handled.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99115936 CN1101976C (en) | 1999-12-14 | 1999-12-14 | Hard X-ray image intensifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99115936 CN1101976C (en) | 1999-12-14 | 1999-12-14 | Hard X-ray image intensifier |
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| Publication Number | Publication Date |
|---|---|
| CN1300093A true CN1300093A (en) | 2001-06-20 |
| CN1101976C CN1101976C (en) | 2003-02-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 99115936 Expired - Fee Related CN1101976C (en) | 1999-12-14 | 1999-12-14 | Hard X-ray image intensifier |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104269337A (en) * | 2014-10-09 | 2015-01-07 | 中国工程物理研究院激光聚变研究中心 | Transmission-type X-ray photoelectric cathode |
-
1999
- 1999-12-14 CN CN 99115936 patent/CN1101976C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104269337A (en) * | 2014-10-09 | 2015-01-07 | 中国工程物理研究院激光聚变研究中心 | Transmission-type X-ray photoelectric cathode |
| CN104269337B (en) * | 2014-10-09 | 2017-01-18 | 中国工程物理研究院激光聚变研究中心 | Transmission-type X-ray photoelectric cathode |
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| Publication number | Publication date |
|---|---|
| CN1101976C (en) | 2003-02-19 |
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