CN100427882C - Gas ionization type middle-low-energy X.gamma-ray detector - Google Patents
Gas ionization type middle-low-energy X.gamma-ray detector Download PDFInfo
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- CN100427882C CN100427882C CNB2006101137026A CN200610113702A CN100427882C CN 100427882 C CN100427882 C CN 100427882C CN B2006101137026 A CNB2006101137026 A CN B2006101137026A CN 200610113702 A CN200610113702 A CN 200610113702A CN 100427882 C CN100427882 C CN 100427882C
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Abstract
This invention relates to a detector technology used in low-middle energy X and gamma ray test control or image system characterizing that a tubular ionization chamber contains a wall as the high voltage pole and central metal tubule as the collector, the end part of the chamber has an end cover sealed by a metal-ceramic sealing insulator and leading out signals, the inside of the ionization chamber is filled with working gas with inert gas as the main component, the tail of the chamber is sealed by thin metal window allowing low and middle energy X and gamma photon to inject.
Description
Technical field:
Low energy X, gamma ray detector belong to the Application of Nuclear Technology technical field in the gas ionization type, relate to being used for low energy X, gamma-rays observing and controlling or imaging system detector technology field.
Background technology:
Current industrial nuclear TT﹠C system, " the convexity meter " that distributes as online detection steel plate section thickness etc. need to adopt the array detecting device of low energy X in surveying, gamma-rays space distribution.With Medical CT or meticulous non-destructive detecting device difference, the spatial resolution of above measuring system requires lower, and the Pixel Dimensions of used array detecting device is bigger, (for example: 5-10mm) is generally inferior centimetre magnitude.Detector array commonly used is the array detecting device that is combined by " scintillator (cesium iodide or cadmium tungstate twinkling crystal)+photodiode " detector array in the industrial nuclear TT﹠C system at present.Middle low energy X, γ photon are injected scintillator and are produced passage of scintillation light, convert it to electric signal by photodiode again.The Pixel Dimensions of this array detecting device is decided with selected photodiode model.For example, select S1337-66BQ/BR type photodiode and the scintillator that matches with it for use after, Pixel Dimensions is 9 * 10mm
2When the thickness of scintillator is enough big, this type of detector will have very high middle low energy X, γ radiation detection efficient (surpassing 60%).Yet the major defect of this class detector is: dark current big (～1 * 10
-10A), to temperature extremely responsive (during use must strict lucifuge), irradiation life is short and stability, reliability are good etc.This can cause many difficulties in occasions such as commercial Application, for example, for overcoming its temperature effect, have to take complex technology to cool off and the temperature of stable sniffer in hot rolled steel plate convexity meter.
Summary of the invention:
The objective of the invention is to overcome the defective of above-mentioned " scintillator+photodiode " detector in the industrial nuclear TT﹠C system (as the convexity meter), propose low energy X, gamma ray detector in the gas ionization type that a kind of front end is provided with the metal thin window.It had both kept high-pressure tightness by the metal thin window of front end, and low energy X, γ photon are injected its sensitive volume in allowing again.Simultaneously, rely on certain sensitive volume length, sufficiently high charge pressure and high atomic number gas composition, make it to have very high detection efficiency and sensitivity.The cross section of this kind ionization chamber is circle, square, rectangle or other shape, and multi-form one dimension or two-dimensional array sniffer can be arranged, be combined into to pixel (cross section) size as required inferior centimetre or cm range.
As everyone knows, gas filled ionization chamber is the widely used gas ionization type detector of a class, it is collected into the electron-ion that ray produces by electrode (high-pressure stage that links with high-voltage power supply and the collector that links with signal system) in the inflation body right, and the output charge signal.Rely on special construction of the present invention, realized to be applied to middle low energy X, the gamma-rays gas ionization type detector array of industrial nuclear TT﹠C system such as convexity meter.By the decision of gas filled ionization chamber principle of work, the dark current of this kind detector is very little (only～10
-13A), and stable, reliable, and to temperature-insensitive, good environmental adaptability, mission life is extremely long.
The invention is characterized in, it is a kind of ionization chamber of tubulose, contain ionization locular wall (02) as the tubulose of high-pressure stage, central metal thin tube (03) as collector, end cap (04) is arranged in the end of this ionization chamber, end caps is with the sealing of metal-ceramic sealing by fusing insulator and draw signal, and being full of with the inert gas in this ionization chamber inside is the working gas of principal ingredient, metal thin window (01) sealing that low energy X, γ photon were injected during the afterbody of this ionization chamber adopted and allows.
The material of described metal thin window (01) is stainless steel, iron, copper, titanium, beryllium or aluminium, and its thickness is 0.01mm-0.9mm.
Described metal thin window (01) and described ionization locular wall (02) adopt the vacuum brazing or the hydrogen furnace sealed with brazing of high-temperature solder.Before carrying out soldering, elder generation is processed into metal thin window (01) flat bowl-shape, then the bowl wall of described metal thin window (01) and the inboard or the outside of described ionization locular wall (02) is welded.
Described metal thin window (01) and described ionization locular wall (02) adopt the argon arc welding sealing, need during welding described metal thin window (01) add one with the identical thin metal ring of described metal foil window material, process slit one in the outside of ionization locular wall (02).
At the contained alumina ceramic tube middle part outside surface metal coating ring of welding (05-3) of described metal-ceramic sealing by fusing insulator, when ionization chamber was worked, described metal coating articulating ground flowed away into ground leakage current.
Charge pressure 0.1～5 MPa of described ionization chamber, the length of its sensitive volume is 20-200mm.
Low energy X, gamma ray detector can constitute one dimension detector array and two-way detector array in the described gas ionization type.
It is little, stable, reliably that the detector that evidence, the present invention propose has a dark current, to advantages such as temperature-insensitive, good environmental adaptability.
Description of drawings:
Fig. 1. the structure of the detector that the present invention proposes, 01 is the metal thin window; 02 is the tubular ionization chamber wall; 03 is the metal tube contre electrode, the double gas outlet of doing ionization chamber; 04 for connecting the end cap of ionization chamber tube wall and metallic ceramics-sealing by fusing insulator; 05 is metal-ceramic sealing by fusing insulator.
Fig. 2. sealed insulation minor structure: corresponding to the shape of two kinds of alumina ceramic tubes (05-2).05-1 is the end cap of sealing by fusing on porcelain tube 05-2, welds mutually with collector 03.05-4 is with porcelain tube sealing by fusing base together, and it welds mutually with ionization chamber end cap 04 again.05-3 is the circle metal of welding on porcelain tube.
Fig. 3. metal thin window (01) is with the brazing mode of ionization locular wall (02): corresponding to two kinds of metal foil window shape.
Fig. 4. metal thin window (01) is with the argon arc welding mode of ionization locular wall (02).
Fig. 5. the combination of one-dimensional array sniffer.
Fig. 6. the combination of two-dimensional array sniffer.
Embodiment:
Describe content of the present invention in detail below in conjunction with accompanying drawing.
As shown in Figure 1, ionization chamber of the present invention is tubing string shape (form of a stroke or a combination of strokes), and its tubular ionization chamber wall (02) is a high-pressure stage, link with high-voltage power supply, and central tubule (03) is a collector, links with signal circuit.The ionization chamber front end is the metal thin window (01) that is sealed with tubular ionization chamber wall (02), is made the little absorption that reduces incident ray of should trying one's best of its thickness by sheet metals such as stainless steel, iron, copper, titanium, beryllium or aluminium.Because the ionization chamber tube wall is thinner, be conserve space, the double gas outlet of doing ionization chamber of central authorities' collector (03), one end is unsettled, the other end is welded on the metal cap (05-1) of metal-ceramic sealing by fusing insulator (05), after treating that exhaust, gas filling technology are finished, this pipe terminal (with the exhaust system connecting place) will be crushed and " weldering is dead ".
In order to reduce the influence of leakage current, metal-ceramic sealing by fusing insulator (05) has " protection ring structure ", as shown in Figure 2.Insulator foot among the figure (05-4) welds mutually with ionization chamber end cap (04), and end cap (05-1) then welds mutually with central collector metal tube (03).Between the two alumina ceramic tube (05-2), respectively with base (05-4) and end cap (05-1) sealing by fusing mutually with superior isolation.In the outside surface welding of the middle part of alumina ceramic tube one the circle metal (05-3), when ionization chamber was worked, this quoit ground connection flowed away into ground leakage current, no longer the undesired signal electric current plays a part " protection ring ".Fig. 2 provides the insulator structure corresponding to two kinds of alumina ceramic tubes (05-2): first kind of porcelain tube simple shape, and easy-sintering processing, but metab (05-4) shape is complicated, and processing capacity is big, and diameter is also big; Second kind of porcelain tube shape is complicated, and difficulty of processing is big, but metal pedestal (05-4) simple shape, diameter is smaller.The metal-ceramic sealing by fusing insulator of these two kinds of forms can both meet the demands.As everyone knows, insulator end cap and base must adopt the expansion coefficient expansion alloy close with pottery to make.
For improving middle low energy X, the gamma-ray detection efficient of detector of the present invention, the inflation component of ionization chamber is that charge pressure is a 0.1-5 MPa scope based on inert gases such as neon, argon, krypton, xenons.In order to improve electronics, the ion mobility in the ionization chamber, accelerate its response time, in the inert gas that is charged into, can suitably sneak into a small amount of polyatomic molecule gas (≤10%), as CO
2Or CH
4Deng.
Because ionization chamber aerated ingredients and pressure is invariable, be to guarantee that its detection performance keeps stable, reliably basic prerequisite, therefore, whole ionization chamber must have fabulous gas tightness.According to current technology condition, can guarantee that fully the leakage rate of inflation in 10 years is less than 1% of total aeration quantity in the ionization chamber.Good like this stability, reliability are that other type detector is incomparable.
For this reason, metal thin window (01) should select to use the vacuum brazing or the technologies such as hydrogen furnace soldering, argon arc welding and plasma welding of high-temperature solder (as yellow gold) with the welding between ionization chamber tube wall (02).In Fig. 3, provide two kinds of structures of thin window soldering, be applicable to vacuum brazing or hydrogen furnace soldering processes.First kind of welded structure is simple, directly foil is soldered on the end face of ionization chamber tube wall with high-temperature solder.Sometimes in order to improve welding quality, on the metal thin window, add a thin metal ring, jointly the metal thin window is clipped in the middle, carry out soldering again with the ionization chamber tube wall.Second kind of welded structure is complicated, needs in advance metal thin window processing (punching press) to be become flat bowl-shape, thereby increases the soldering area, improves compressive resistance.At this moment, the metal thin window " is bent " edge that comes out, be buckled in the inside surface or the outside surface (as shown in Figure 3) of ionization chamber tube wall, carries out soldering.In Fig. 4, provided the argon arc welding structure of metal window and ionization chamber tube wall.For guaranteeing welding quality, need be at the preceding additional again thin metal ring of metal window (01), simultaneously process slit one in tube wall (02) end, shown in [A] among Fig. 4, thin metal ring can prevent that together with slit the thin metal window that thermal capacity is little in the argon arc welding process from " subsiding " taking place, and guarantees welding quality.
When low-melting-point metal thin windows such as aluminium,, can adopt glued Sealing Technology for overcoming the welding difficulty.
Argon arc welding should be adopted between ionization chamber tube wall (02) and ionization chamber end cap (04), and argon arc welding or vacuum drying oven (hydrogen stove) soldering can be selected between end cap (04) and the metal-ceramic sealing by fusing insulator (05) for use.The molten sealed insulator of metal-ceramic (05) is the commodity of market supply, and the metal-ceramic sealing by fusing technology of code requirement can guarantee extraordinary air seal performance.
Be to guarantee the ionization chamber that impermeability, metal-ceramic sealing by fusing insulator (05), metal thin window (01) wait other parts and general assembly, welding to finish, all need to carry out repeatedly strict helium and stop leakage in the roof and withstand voltage test.
Be low energy X, gamma-ray detection in adapting to, front end metal thin window must be enough thin.For example, can adopt the stainless steel substrates of thickness in the 0.01-0.9mm scope, or the titanium sheet of similar thickness, beryllium sheet and other sheet metal.Often the sheet thickness that uses is 0.05mm, 0.1mm, 0.15mm, 0.2mm and 0.3mm etc.
The sensitive volume length of ionization chamber of the present invention is with energy, inflation kind and the pressure correlation of incident ray.The general charge pressure of selecting is no more than 5 MPas, and length is then in 20-200mm scope or longer.
Ionization chamber of the present invention will can rearrange middle low energy X, the gamma-rays array detecting device of multi-form one dimension or bidimensional on request as a pixel element of sniffer.Provided a kind of one-dimensional array sniffer of being made up of ionization chamber of the present invention in Fig. 5, this device is linearly.Equally, also can arrange the one-dimensional array sniffer that is mounted to fan-shaped, " Γ " shape, " ∏ " shape or other shape.In Fig. 6, provided a kind of square two-dimensional array sniffer of forming by ionization chamber of the present invention.If desired, also can arrange the two-dimensional array sniffer that is mounted to other form.
The present invention has been owing to realized middle low energy X, the gamma-rays array detecting device of ionization chamber type, thus have dark current little, to advantages such as light and temperature-insensitive, reliable and stable, long working lifes.
The present invention is the tubular inflating ionization chamber that is provided with the metal thin window at front end, can make up, be arranged as low energy X in various forms of one dimensions or the two dimension, gamma-rays array detecting device on demand, be applicable to radiation image-forming detecting systems such as plate crown meter industrial nuclear TT﹠C system such as (Profile Gauge) or case and bag CT examination equipment.
Embodiment:
1. fan-shaped one-dimensional array sniffer:
" thin window cylindricality ionization chamber " is cylindrical, and its metal thin window adopts the 0.1mm stainless steel substrates, and the ionization locular wall is Φ 10 * 1mm gapless stainless steel tube, length 12cm, central collector Φ 2 * 0.2mm stainless-steel tube, and end cap is also made with stainless steel.
Affixed between metal thin window and the tubular ionization chamber wall with hydrogen furnace silver soldering (with 72: 28 yellow gold scolders).Also adopt hydrogen furnace silver soldering between end cap and metal-ceramic sealing by fusing insulator, and it is with adopting argon arc welding between the tubular ionization chamber wall.
Fill Xe-CO in the ionization chamber with 3 MPa pressure
2Combination gas will reach about 80% the X of average energy 60keV, the detection efficiency of γ photon.
128 these kinds " thin window cylindricality ionization chamber " are arranged be installed on the fan, be equipped with corresponding front-end circuit, promptly constitute low energy X, gamma-rays array detecting device in one group of fan-shaped one dimension with 128 pixel detector units.
2. square two-dimensional array sniffer:
" thin window cylindricality ionization chamber " is identical with above embodiment.
900 " thin window ionization chamber " arranged be installed on 30 * 30 the square matrix-shaped support, be equipped with corresponding front-end circuit, promptly constitute one group of 30 * 30 two-dimensional array sniffer with 900 pixel detector units.
Claims (10)
1, low energy X, gamma ray detector in the gas ionization type, it is characterized in that, it is a kind of ionization chamber of tubulose, contain ionization locular wall (02) as the tubulose of high-pressure stage, central metal thin tube (03) as collector, end cap (04) is arranged in the end of this ionization chamber, end caps is with the sealing of metal-ceramic sealing by fusing insulator and draw signal, being full of with the inert gas in this ionization chamber inside is the working gas of principal ingredient, metal thin window (01) sealing that low energy X, γ photon were injected during the afterbody of this ionization chamber adopted and allows.
2, low energy X, gamma ray detector in the gas ionization type as claimed in claim 1 is characterized in that, the material of described metal thin window (01) is stainless steel, iron, copper, titanium, beryllium or aluminium.
3, low energy X, gamma ray detector in the gas ionization type as claimed in claim 1 is characterized in that, the thickness of described metal thin window (01) is 0.01mm-0.9mm.
4, low energy X, gamma ray detector in the gas ionization type as claimed in claim 1 is characterized in that, described metal thin window (01) and described ionization locular wall (02) adopt the vacuum brazing or the hydrogen furnace sealed with brazing of high-temperature solder.
5, low energy X, gamma ray detector in the gas ionization type as claimed in claim 4, it is characterized in that, before described metal thin window (01) and described ionization locular wall (02) carry out soldering, elder generation is processed into metal thin window (01) flat bowl-shape, then the bowl wall of described metal thin window (01) and the inboard or the outside of described ionization locular wall (02) is welded.
6, low energy X, gamma ray detector in the gas ionization type as claimed in claim 1, it is characterized in that, described metal thin window (01) adopts the argon arc welding sealing with described ionization locular wall (02), need during welding described metal thin window (01) add one with the identical thin metal ring of described metal foil window material, process slit one in the outside of ionization locular wall (02).
7, low energy X, gamma ray detector in the gas ionization type as claimed in claim 1; it is characterized in that; at the contained alumina ceramic tube middle part outside surface metal coating ring of welding (05-3) of described metal-ceramic sealing by fusing insulator; when ionization chamber is worked; described metal coating articulating ground flows away into ground leakage current.
8, low energy X, gamma ray detector in the gas ionization type as claimed in claim 1 is characterized in that, charge pressure 0.1～5 MPa of described ionization chamber, and the length of its sensitive volume is 20-200mm.
9, the one dimension detector array that constitutes according to low energy X, gamma ray detector in the described gas ionization type of one of claim 1 to 8.
10, the two-way detector array that constitutes according to low energy X, gamma ray detector in the described gas ionization type of one of claim 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006101137026A CN100427882C (en) | 2006-10-13 | 2006-10-13 | Gas ionization type middle-low-energy X.gamma-ray detector |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006101137026A CN100427882C (en) | 2006-10-13 | 2006-10-13 | Gas ionization type middle-low-energy X.gamma-ray detector |
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| Publication Number | Publication Date |
|---|---|
| CN1936498A CN1936498A (en) | 2007-03-28 |
| CN100427882C true CN100427882C (en) | 2008-10-22 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102200434A (en) * | 2011-04-02 | 2011-09-28 | 清华大学 | Thickness and convexity detection device for plates and strips |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3961196A (en) * | 1973-08-03 | 1976-06-01 | Alexeev Viktor I | Miniature ionization chamber |
| US4583020A (en) * | 1982-07-13 | 1986-04-15 | Commissariat A L'energie Atomique | Ionization chamber making it possible to measure high energy gamma radiation |
| JPH08101276A (en) * | 1994-09-30 | 1996-04-16 | Toshiba Corp | Gamma-ray detector |
| JP2001013249A (en) * | 1999-06-29 | 2001-01-19 | Toshiba Eng Co Ltd | Radiation detector |
| CN1290858A (en) * | 1998-04-03 | 2001-04-11 | 清华大学 | Detector array for ionization chamber and its use |
| CN1749778A (en) * | 2004-09-14 | 2006-03-22 | 清华大学 | Small size penetration ionization chamber for monitoring X-ray source dosage rate |
-
2006
- 2006-10-13 CN CNB2006101137026A patent/CN100427882C/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3961196A (en) * | 1973-08-03 | 1976-06-01 | Alexeev Viktor I | Miniature ionization chamber |
| US4583020A (en) * | 1982-07-13 | 1986-04-15 | Commissariat A L'energie Atomique | Ionization chamber making it possible to measure high energy gamma radiation |
| JPH08101276A (en) * | 1994-09-30 | 1996-04-16 | Toshiba Corp | Gamma-ray detector |
| CN1290858A (en) * | 1998-04-03 | 2001-04-11 | 清华大学 | Detector array for ionization chamber and its use |
| JP2001013249A (en) * | 1999-06-29 | 2001-01-19 | Toshiba Eng Co Ltd | Radiation detector |
| CN1749778A (en) * | 2004-09-14 | 2006-03-22 | 清华大学 | Small size penetration ionization chamber for monitoring X-ray source dosage rate |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102200434A (en) * | 2011-04-02 | 2011-09-28 | 清华大学 | Thickness and convexity detection device for plates and strips |
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| CN1936498A (en) | 2007-03-28 |
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