CN102196655B - Multi-filament wide-beam electronic curtain - Google Patents

Abstract

The invention relates to a radiation processing and nuclear technology accelerator, disclosing a multi-filament wide-beam electronic curtain. The multi-filament wide-beam electronic curtain comprises a control system, a power supply system, a water cooling system, a nitrogen supply system and a vacuum system, wherein the power supply system comprises a high-voltage power supply, a head power supply and an isolation transformer; the head power supply is connected with high-voltage ceramics by a high-voltage inlead; the vacuum system comprises an electronic gun, an external barrel and filaments, wherein a vacuum cavity is formed between the electronic gun and the external barrel; the lower side of the electronic gun is provided with a second grid electrode of the flat plate shape; the second grid electrode is provided with a second grid aperture; a titanium foil and an acceleration electrode are arranged just below the second grid electrode; and the titanium foil is provided with a cooled copper grid. In the radiation processing and nuclear technology accelerator, the density of the filament is reasonably set to overcome the distribution unevenness of end beam current because of titanium foil dispersion; the second grid electrode is provided with the second grid aperture to reduce cut beams on the titanium foil copper grid; and an outer layer of shielding cover is also provided with a distribution target so as to monitor beam current distribution in real time to greatly improve the performance of the whole accelerator.

Description

Multi-filament broad beam electron curtain

Technical field

The present invention relates to RADIATION PROCESSING and nuclear technology accelerator, relate in particular to Multi-filament broad beam electron curtain.

Background technology

Energy is 80-300keV, width is that the electron curtain of 20-350cm is widely used in the RADIATION PROCESSING field, and for example face coat solidifies, and generates new material and the components and parts of property by the crosslinked or cracking reaction that produces when the radiation, desulfurizing industrial fume, radiosterilization etc.RADIATION PROCESSING has energy-conservation, and economic benefit is high, the advantages such as environmentally safe.Carry out RADIATION PROCESSING with electron curtain, although from last century a swift and violent development is arranged after the eighties abroad, not yet extensively carry out in this field at home, and its market is still very broad.It is good that the key of this field development will be researched and developed a performance exactly, and cost performance is high, and is reliable and stable, and the electron curtain of various width can be provided.

Although electron curtain at home existing some research institutes company copies or with external cooperation research and development, there is no the Multi-filament broad beam electron curtain with independent intellectual property right.

Summary of the invention

The uniformity that the present invention is directed to radiation area bundle in the prior art can't guarantee, provides a kind of very high current density and very wide beamwidth can be provided, the multi-filament electron curtain that requires to adapt to various applications.

In order to solve the problems of the technologies described above, the present invention is solved by following technical proposals:

During the selection of negative electrode mode of operation, be the uniformity that guarantees the radiation area bundle, must guarantee that at first the electric current that each electron gun is drawn will be unanimously.The electron gun of this electron curtain is by many linear hot filaments and draws the grid parallel connection and consist of.First grid is the coaxial cylinders that surrounds filament.The design of negative electrode and grid is the key of whole accelerator.Consistent for guaranteeing the electric current that each electron gun draws, at first want the mode of operation of choose reasonable negative electrode.Negative electrode has two kinds of mode of operations available:

A. the emission restriction is flowed: emission restriction stream is determined by cathode temperature.All thermionic emission all satisfy following formula:

$J={\mathrm{<figure-callout\; id="2"\; label="AT"\; filenames="100311095637.png"\; state="\{\{state\}\}">AT</figure-callout>}}^2\exp \frac{e}{\mathrm{kT}}$

Wherein e is the cathode surface work function.Can be derived by following formula

$\frac{\mathrm{dJ}}{J}\&ap;2+\frac{e}{\mathrm{kT}}\frac{\mathrm{dT}}{T}$

Index variation in the various negative electrode following formulas is very little.Can be seen that by following formula for the emission current that makes each electron gun satisfies ± 10% requirement, each cathode temperature must be controlled.Cathode temperature is controlled by heating current, finds that by Practical Calculation following approximate formula is arranged between filament heating electric current and temperature when filament temperature is enough high:

I _f=k(T?T _o)

$\frac{{\mathrm{dI}}_f}{I_f}=\frac{d{V}_f}{V_f}\&ap;7\&times;{10}^4\mathrm{dT}$

V wherein _fFilament heating voltage.As can be known, require each filament emission current error＜± 10%, the difference between current that just necessarily requires to flow through every filament is little.If we are by a Power supply, though the voltage at all filament two ends all identical (this resistance that requires the filament frame of power supply is zero), by

D wherein, l is diameter and the length of filament; Can obtain:

Therefore, require the error of diameter

The error of length

Above-mentioned two requirements all will be difficult technically.

B. space-charge-limited flow: the formula that can use two space-charge-limited flow between the face of cylinder:

Wherein J=I/H is the stream of drawing of unit length, V=V _fBe extraction voltage, θ is the subtended angle of draw-out area,

r _aThe anode cylinder radius, r _cIt is the cathode cylinder radius.In our situation, because r _a/ r _c(work as r very greatly _a/ r _c1 o'clock, β ²→ 1), can think

$J=\mathrm{<figure-callout\; id="3"\; label="k\; V"\; filenames="100310165302.png"\; state="\{\{state\}\}">k</figure-callout>}\frac{V^{}}{}\frac{{}^{3/2}}{r_a}$

R in our situation wherein _aBe the first grid radius.

For guaranteeing that the line uniformity that each electron gun is drawn reaches the requirement of Δ I/I=± 10%, supposes r _a=10mm then requires Δ r _a＜± 1mm.Namely only need to guarantee each filament with respect to the site error of the first grid be controlled at ± 1mm in.We are equipped with the device with filament tension in the one or both ends of each filament, overcome the sagging problem behind the filament heating, and this requirement is satisfiable technically.

Multi-filament broad beam electron curtain, comprise control system, electric power system, water-cooling system, nitrogen supply system and vacuum system, described electric power system comprises high voltage source, head power supply and isolating transformer, the head power supply is connected with higfh-tension ceramics by the high pressure lead-in, vacuum system comprises electron gun, outer cylinder body, 2-150 filament, it is vacuum chamber between electron gun and the outer cylinder body, the downside of electron gun is provided with plate shaped second grid, second grid is provided with the second gate hole, be provided with titanium foil and intensifying ring under the second grid, 2-600 cooling copper grid that is parallel to each other is set on the titanium foil, filament is provided with columnar first grid outward, the positive pole of head power supply links to each other with filament one end, the negative pole of head power supply links to each other with the other end of filament, filament and first grid depart from a distance, filament with respect to second grid to the negative pole direction of head power supply, first grid, second grid departs from a distance with respect to titanium foil to the negative pole direction of head power supply.Multi-filament broad beam electron curtain, energy are 80-300keV, and beamwidth is 50-350cm, and the skew effect of " crossed electric and magnetic field " halved tie is supposed the electron curtain electron gun structure of employing as shown in Figure 3.Filament is arranged in Z axis, and first grid is R for the radius around filament ₁Cylinder.Second grid is to be R with the filament distance ₂The plane.First grid adds draws grid voltage V _g, be the equipotential drift region between the first and second grids.For the bundle that adjacent electron gun is drawn intersects as much as possible mutually, make the abundant homogenize of bundle to reach, (2 θ in certain subtended angle scope below first grid _Max) opened many holes, electronics is drawn.As shown in Figure 2, the magnetic field that electric current produces is the concentric circles around filament, and the direction of an electric field between filament and the first grid is radially.Therefore electronics will be to the Z direction, the drift of the anode of filament voltage.

In theory, the equation of motion (using the MKS system) of electronics is as follows in the cross(ed) field:

$m\frac{d^2\mathrm{<figure-callout\; id="2"\; label="z\; d\; t"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}{d{t}^{}}=e{B}_{\mathrm{\&theta;}}\frac{\mathrm{dr}}{\mathrm{dt}}=e{B}_{\mathrm{\&theta;}}{v}_r=e\frac{2I_f{\mathrm{\&mu;}}_o}{4\mathrm{\&pi;r}}{v}_r$

$m\frac{d^2\mathrm{<figure-callout\; id="2"\; label="r\; d\; t"\; filenames="100311095637.png"\; state="\{\{state\}\}">r</figure-callout>}}{d{t}^{}}=e{E}_r=\frac{e{V}_g}{r\ln ({\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_1/r_o)}$

R wherein _oThe filament radius, μ _o=4 π * 10 ⁷H/m.Can in the hope of, total drift value is determined by following formula when arriving second gate:

z ₂≈Δz ₁+Δz ₂

Δ z wherein ₁Drift value when arriving first grid, can be in the hope of being determined by following formula:

$\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_1=\underset{r_o}{\overset{R_1}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_o}{2\mathrm{\&pi;m}}\sqrt{\ln (r/r_o)}\frac{2e{V}_g}{m\ln ({\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_1/r_o)}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; f"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_f^{}{\mathrm{\&mu;}}_o^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {(r/r_o)}^{1/2}\mathrm{dr}$

The electronics that different θ directions are drawn has identical z to speed when arriving the first grid, and the slope of electron trajectory is determined by following equation:

It is equipotential drift region (formula between the first and second grids

Middle right-hand member is zero).The distance length that the electronics that different θ directions are drawn flies when arriving second gate is different.For the electron beam of vertically drawing (θ=0), flight distance the shortest (OA), so the drift distance of z direction is the shortest, determined by following formula:

$\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="20"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_{20}=\underset{R_1}{\overset{R_2}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_o}{2\mathrm{\&pi;m}}\ln (r/r_o)\frac{2e{V}_g}{m}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; f"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_f^{}{\mathrm{\&mu;}}_o^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {\frac{r^2}{r_o}}^{1/2}\mathrm{dr}$

The side-play amount of electron beam between the first grid and second gate of drawing by the θ angle is:

$\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_2=\underset{R_1}{\overset{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_2/\cos \mathrm{\&theta;}}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_o}{2\mathrm{\&pi;m}}\ln (r/r_o)\frac{2e{V}_g}{m}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; g"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_g^{}{\mathrm{\&mu;}}_o^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {\frac{r^2}{r_o}}^{1/2}\mathrm{dr}$

θ is larger, and side-play amount is larger, and the result just forms semi-moon shaped bundle spot as shown in Figure 4 when arriving second gate.The result who calculates by above-mentioned formula compares with the series of experiments measurement, and the result is consistent.Although above-mentioned theory derives under how much of the cylindric first grids, even when the first grid is the plane, because near the equipotential surface of the strongest filament of cross(ed) field effect is done approximate estimation still near cylindrical shape so still can use above-mentioned theory.

Since at the second gate place Shu Youyi z to drift velocity, so when restrainting when accelerating to the titanium foil window by second gate, also can further cause z to drift (Δ z ₃).

The result that above-mentioned phenomenon produces is: (1) electronics is drawn with acceleration efficiency extremely low.(2) bundle of outgoing second gate is distributed in the filament both sides and sharply descends.The mutual intersection that adjacent electronics is robbed bundle reduces greatly, need to reduce the distance of adjacent electronics between robbing, the uniformity of guarantee accelerator ejected beam.So, increased the filament heating electric current.This not only increases power consumption, and brings technical great difficulty.(3) behind second gate, because the initial velocity of a Z-direction is arranged, will be further to amount of filament anode skew when arriving titanium foil after whole bundle accelerates.(4) bundle spot in titanium foil place seriously is partial to a side, and effectively line reduces, and heat distribution and the cooling thereof of titanium foil brought impact.In a word, this phenomenon produces the impact of essence for the performance of whole electron curtain.

As preferably, described filament length is 3-15cm, filament is provided with columnar first grid outward, the end of first grid is provided with back-moving spring, the tolerance of filament and first grid distance is ± 1mm, the downside half angle of first grid is to be provided with the first grid hole that electron beam passes through in the 30-120 ° of scope, and the positive pole of head power supply links to each other with filament one end, and the negative pole of head power supply links to each other with the other end of filament.Filament and first grid assembly are departed from a distance with respect to second grid to the negative pole direction of head power supply, the positive pole of filament supply links to each other with each filament one end, power cathode links to each other with the filament other end, filament so all to the positive terminal drift, still concentrates in the spendable scope a large amount of electronics.Improved that electronics is drawn and acceleration efficiency, avoided the bundle of outgoing second grid to be distributed in the rapid decline of filament both sides and to get in a large number outside electric current and cause many ill effects.Guarantee the uniformity of accelerator ejected beam, reduced the filament heating electric current, reduced power consumption.Filament-first grid-second grid assembly departs from a distance (Δ z with respect to titanium foil to the negative pole direction of head power supply ₃), suitably increase first grid diameter and grid voltage, thereby the spacing that reduces first grid and second grid owing to the initial velocity that a Z-direction is arranged, will further be offset an amount to the filament anode when arriving titanium foil after whole bundle accelerates behind second grid.

To produce very large scattering when penetrating titanium foil owing to electron beam, even restraint when the incident titanium foil fully evenly as calculated, the effect of scattering will make the dosage of radiation area produce decline at two ends.Close to the irradiation face was healed from the paper tinsel film, dosage was healed large, and the border is steeper, and distribution is healed evenly, and homogeneity range is larger.By the distance between shortening paper tinsel film and the irradiation thing and through strengthening the length of electron gun and titanium foil, perhaps add the light orchid behind the titanium foil before the adjacent irradiation thing and can solve the inhomogeneous problem of dosage, still reduced the utilance of beam power.Therefore by encrypt the filament interval at two ends, cause titanium foil incident place two ends that larger beam current density is arranged, thereby reach the uniformity behind titanium foil.

As preferably, the diameter of described first grid is 1-4cm, and the spacing between first grid and the second grid is 1-600mm.

As preferably, described second gate hole is that diameter is the round hole of 2.5-6mm.Have the round hole of drawing electron beam on the second grid, can reduce the titanium foil copper grid that beam divergence angle causes and cut the bundle rate.

As preferably, described second gate hole be width at 2.5-5mm, length is the rectangle perforate in the scope of 10-200mm.Have the rectangle perforate of drawing electron beam on the second grid, can reduce the titanium foil copper grid that beam divergence angle causes and cut the bundle rate.

As preferably, select the negative electrode mode of operation, and adopt space-charge-limited flow state or emission restriction stream, also be provided with dose monitoring system on the outer cylinder body, dose monitoring system is the measurement target of detected electrons stream.The mode of operation of the choose reasonable negative electrode that proposes adopts the space-charge-limited flow state, guarantees that effectively each filament of multi-filament draws identical electron stream, adopts emission restriction stream, more is conducive to the uniformity of single filament type electron curtain ejected beam.Real-Time Monitoring electronic beam current and Beam distribution are very important during operation, for this reason, many distribution targets are settled in the side between titanium foil and irradiation thing, be used for monitoring the educt beaming flow density distribution, therefore cause when owing to single filament blow that the bundle density distribution can in time stop to produce when changing, also settled simultaneously two absorbing targets, be provided with scale on the absorbing target and can indicate and draw total beam.

As preferably, described cooling copper grid is straight or arc, and the height of cooling copper grid is 5-50mm, width is 0.6-2mm, distance between the adjacent cooling copper grid is 0.5-7mm, and cooling copper grid is the water-cooled copper grid, and by cooling off titanium foil to the mode of titanium foil blowing.Calculating shows, loose angle when electron beam reaches titanium foil mainly is produced by the impact of focal length and pore membrane lens at electron beam, if cooling copper grid adopts circular hole or square hole, the equipotential surface of indent is dome shape, so will produce bidimensional (X, Y-direction) loose angle, and the copper grid of cooling titanium foil are slotted along a direction (for example Y-direction).So, electron beam will produce at directions X the shade of copper grid, thereby strengthen the bundle that cuts of copper grid.If open slit along directions X on second grid, then to be cylinder planar for the equipotential surface of indent, only produces loose angle in Y-direction, so can greatly reduce the bundle rate of cutting of copper grid.Through calculating, like this can be so that the cutting about the about drop by half of bundle rate of copper grid, so this change will make the load of high voltage source greatly descend, and bring very large economic benefit.

As preferably, described titanium foil adopts the beryllium paper tinsel of aluminizing to replace, and the thickness of the beryllium paper tinsel of aluminizing is 5-40 μ m, and width is 2-35cm.The material of titanium foil is selected: conductive coefficient allows the maximum operation temperature of operation to heal height better more better, and the ENERGY DEPOSITION COEFFICIENTS FOR of electronics in the paper tinsel film heals better little, and yield strength more better.Film materials commonly used is titanium or aluminium, and the working temperature of titanium is high, but poor heat conductivity; Aluminium in contrast.The conductive coefficient of beryllium is seven times of titanium, and the ENERGY DEPOSITION COEFFICIENTS FOR of beryllium paper tinsel only is 80% of titanium foil.Beryllium also has the advantages such as high-modulus, high specific stiffness, resistance to oxidation, good stability of the dimension, but that its shortcoming is valency is expensive, and the beryllium powder is poisonous, and property is more crisp, so use the beryllium paper tinsel of aluminizing.

As preferably, described filament and first grid depart from 5-150mm with respect to second grid to the negative pole direction of head power supply, and filament, first grid, second grid depart from 5-350mm with respect to titanium foil to the negative pole direction of head power supply.Because wire filament type electron gun is in the lower phenomenon that will cause that serious bundle is offset of " crossed electric and magnetic field " effect, and the having a strong impact on whole electron curtain device that cause of this phenomenon.The theoretical calculation formula of deriving:

${\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_2\&ap;\mathrm{\&Delta;}{z}_1+\mathrm{\&Delta;}{z}_2\&ap;\underset{r_o}{\overset{R_1}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_o}{2\mathrm{\&pi;m}}\sqrt{\ln (r/r_o)}\frac{2e{V}_g}{m\ln ({\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_1/r_o)}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; f"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_f^{}{\mathrm{\&mu;}}_o^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {(r/r_o)}^{1/2}\mathrm{dr}$

$+\underset{R_1}{\overset{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_2/\cos \mathrm{\&theta;}}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_o}{2\mathrm{\&pi;m}}\ln (r/r_o)\frac{2e{V}_g}{m}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; f"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_f^{}{\mathrm{\&mu;}}_o^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {\frac{r^2}{r_o}}^{1/2}\mathrm{dr}$

Therefore, filament and first grid assembly are departed from the 20-100mm distance with respect to second gate to the negative pole direction of power supply; Filament-first grid-second gate assembly is departed from the 20-350mm distance with respect to titanium foil to the negative pole direction of power supply; Suitably increase first grid diameter and grid voltage, reduce the bundle shift phenomenon that the spacing of the first grid and second gate can make electron gun cause and greatly weaken under " crossed electric and magnetic field " effect.

As preferably, described intensifying ring adopts single gap to accelerate electronics, and the scope in gap is 3-60cm.

For a wide beam source, one of most important key problem in technology is the uniformity that how to guarantee the radiation area bundle, the mode of operation of the choose reasonable negative electrode that the present invention finds, reduce that to make electron beam produce effect that serious skew causes and the density of reasonable disposition two ends filament etc. under the effect of " crossed electric and magnetic field " all be the performance that improves whole accelerator, must Adopts measure such as ejected beam spot shape, ejection efficiency, the uniformity etc.

The mode of operation of choose reasonable negative electrode of the present invention guarantees that the line that each filament draws is even, and derived theoretically and make electron beam produce the computing formula of skew under the effect of " crossed electric and magnetic field ", by the introducing mode of the theoretical method that combines with experiment with filament skew or change filament supply, greatly reduce the serious consequence that it causes.Density by the reasonable arrangement filament overcomes the end line nonunf ormity that the titanium foil scattering causes, at second grid the second gate hole is set, reduce the bundle that cuts on the titanium foil copper grid, the distribution target also is set on the external shield, can the Real-Time Monitoring line distribute and ejected beam spot shape, ejection efficiency, the uniformity etc., greatly improve the performance of whole accelerator.

Description of drawings

Fig. 1 is principle of the invention schematic diagram.

Fig. 2 is electronics of the present invention stressed schematic diagram in crossed fields.

Fig. 3 is that crossed fields of the present invention affects principle schematic to electron trajectory.

Fig. 4 is the bundle spot of the skew of cross(ed) field effect generation of the present invention.

Fig. 5 is the shade of the bundle of titanium foil cooling copper grid of the present invention generation.

1-electric power system wherein, 2-vacuum system, 3-electron beam, 4-magnetic line of force, 5-power line, bundle spot after the skew of 6-electronics, 11-high voltage source, 12-head power supply (filament supply, grid power supply), 13-isolating transformer, 14-high pressure lead-in, 15-higfh-tension ceramics, 21-filament, 22-first grid, 23-electron gun, 24-second grid, 25-intensifying ring, 26-titanium foil, 27-cooling copper grid, 28-dose monitoring system, 29-outer cylinder body, 221-first grid hole, 241-second gate hole.

Embodiment

Below in conjunction with accompanying drawing 1 to accompanying drawing 4 and embodiment the present invention is described in further detail:

Embodiment 1

Multi-filament broad beam electron curtain, as shown in Figures 1 to 4, comprise control system, electric power system 1, water-cooling system, nitrogen supply system and vacuum system 2, described electric power system 1 comprises high voltage source 11, head power supply 12 and isolating transformer 13, head power supply 12 is connected with higfh-tension ceramics 15 by high pressure lead-in 14, vacuum system 2 comprises electron gun 23, outer cylinder body 29,50 filaments 21, be vacuum chamber 20 between electron gun 23 and the outer cylinder body 29, the downside of electron gun 23 is provided with plate shaped second grid 24, second grid 24 is provided with second gate hole 241, be provided with titanium foil 26 and intensifying ring 25 under the second grid 24,55 cooling copper grids 27 that are parallel to each other are set on the titanium foil 26.Multi-filament broad beam electron curtain, energy are 80-300keV, and beamwidth is 50-350cm, and the skew effect of " crossed electric and magnetic field " halved tie is supposed the electron curtain electron gun structure of employing as shown in Figure 3.Filament is arranged in Z axis, and first grid is R for the radius around filament ₁Cylinder.Second grid is to be R with the filament distance ₂The plane.First grid adds draws grid voltage V _g, be the equipotential drift region between the first and second grids.For the bundle that adjacent electron gun is drawn intersects as much as possible mutually, make the abundant homogenize of bundle to reach, 2 θ in certain subtended angle scope below first grid _MaxOpened many holes, electronics has been drawn.As shown in Figure 2, the magnetic field that electric current produces is the concentric circles around filament, and the direction of an electric field between filament and the first grid is radially.Therefore electronics will be to the Z direction, the drift of the anode of filament voltage.

Filament 21 length are 8cm, be provided with columnar first grid 22 outside the filament 21, the end of first grid 22 is provided with back-moving spring, filament 21 with the tolerance of first grid 22 distances is ± 1mm, the downside half angle of first grid 22 is to be provided with the first grid hole 221 that electron beam passes through in 52 ° of scopes, the positive pole of head power supply links to each other with an end of filament 21, and the negative pole of head power supply links to each other with the other end of filament 21.Filament and first grid assembly are departed from a distance with respect to second grid to the negative pole direction of head power supply, the positive pole of filament supply links to each other with each filament, power cathode links to each other with the filament other end, filament so all to the positive terminal drift, still concentrates in the spendable scope a large amount of electronics.Improved that electronics is drawn and acceleration efficiency, avoided the bundle of outgoing second grid to be distributed in the rapid decline of filament both sides and to get in a large number outside electric current and cause many ill effects.Guarantee the uniformity of accelerator ejected beam, reduced the filament heating electric current, reduced power consumption.Filament-first grid-second grid assembly departs from a distance, delta z with respect to titanium foil to the negative pole direction of head power supply ₃, suitably increase first grid diameter and grid voltage, thereby the spacing that reduces first grid and second grid owing to the initial velocity that a Z-direction is arranged, will further be offset an amount to the filament anode when arriving titanium foil after whole bundle accelerates behind second grid.

To produce very large scattering when penetrating titanium foil owing to electron beam, even restraint when the incident titanium foil fully evenly as calculated, the effect of scattering will make the dosage of radiation area produce decline at two ends.Close to the irradiation face was healed from the paper tinsel film, dosage was healed large, and the border is steeper, and distribution is healed evenly, and homogeneity range is larger.By the distance between shortening paper tinsel film and the irradiation thing and through strengthening the length of electron gun and titanium foil, perhaps add the light orchid behind the titanium foil before the adjacent irradiation thing and can solve the inhomogeneous problem of dosage, still reduced the utilance of beam power.Therefore by encrypt the filament interval at two ends, cause titanium foil incident place two ends that larger beam current density is arranged, thereby reach the uniformity behind titanium foil.

The diameter of first grid 22 is 2cm, and the spacing between first grid 22 and the second grid 24 is 100mm.

Second gate hole 241 is the round hole of 3mm for diameter.Have the round hole of drawing electron beam on the second grid 24, can reduce the titanium foil copper grid that beam divergence angle causes and cut the bundle rate.

Select the negative electrode mode of operation, and adopt space-charge-limited flow state or emission restriction stream, also be provided with dose monitoring system 28 on the outer cylinder body 29, dose monitoring system 28 is the measurement target of detected electrons stream.The mode of operation of the choose reasonable negative electrode that proposes adopts the space-charge-limited flow state, guarantees that effectively each filament of multi-filament draws identical electron stream, adopts emission restriction stream, more is conducive to the uniformity of single filament type electron curtain ejected beam.Real-Time Monitoring electronic beam current and Beam distribution are very important during operation, for this reason, many distribution targets are settled in the side between titanium foil and irradiation thing, be used for monitoring the educt beaming flow density distribution, therefore cause when owing to single filament blow that the bundle density distribution can in time stop to produce when changing, also settled simultaneously two absorbing targets, be provided with scale on the absorbing target and can indicate and draw total beam.

Cooling copper grid 27 is straight copper coin, and the height of cooling copper grid 27 is 10mm, and width is 0.8mm, and the distance between the adjacent cooling copper grid 27 is 2mm, and cooling copper grid 27 is the water-cooled copper grid, and by cooling off titanium foil 26 to the mode of titanium foil 26 blowings.Calculating shows, loose angle when electron beam reaches titanium foil mainly is produced by the impact of focal length and pore membrane lens at electron beam, if cooling copper grid adopts circular hole or square hole, the equipotential surface of indent is dome shape, so will produce bidimensional X, the loose angle of Y-direction, and the copper grid of cooling titanium foil are along direction Y-direction fluting for example.So, electron beam will produce at directions X the shade of copper grid, thereby strengthen the bundle that cuts of copper grid.If open slit along directions X on second grid, then to be cylinder planar for the equipotential surface of indent, only produces loose angle in Y-direction, so can greatly reduce the bundle rate of cutting of copper grid.Through calculating, like this can be so that the cutting about the about drop by half of bundle rate of copper grid, so this change will make the load of high voltage source greatly descend, and bring very large economic benefit.

The beryllium paper tinsel of titanium foil 26 for aluminizing, the thickness of titanium foil 26 is 10 μ m, width is 8cm.The material of titanium foil 26 is selected: conductive coefficient allows the maximum operation temperature of operation to heal height better more better, and the ENERGY DEPOSITION COEFFICIENTS FOR of electronics in the paper tinsel film heals better little, and yield strength more better.Film materials commonly used is titanium or aluminium, and the working temperature of titanium is high, but poor heat conductivity; Aluminium in contrast.The conductive coefficient of beryllium is seven times of titanium, and the ENERGY DEPOSITION COEFFICIENTS FOR of beryllium paper tinsel only is 80% of titanium foil.Beryllium also has the advantages such as high-modulus, high specific stiffness, resistance to oxidation, good stability of the dimension, but that its shortcoming is valency is expensive, and the beryllium powder is poisonous, and property is more crisp, so use the beryllium paper tinsel of aluminizing.

Filament 21 and first grid 22 depart from 62mm with respect to second grid 24 to the negative pole direction of power supply, and filament 21, first grid 22, second grid 24 depart from 121mm with respect to titanium foil 26 to the negative pole direction of power supply.Because wire filament type electron gun is in the lower phenomenon that will cause that serious bundle is offset of " crossed electric and magnetic field " effect, and the having a strong impact on whole electron curtain device that cause of this phenomenon.The theoretical calculation formula of deriving:

${\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_2\&ap;\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_1+\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_2\&ap;\underset{r_o}{\overset{R_1}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}}{2\mathrm{\&pi;m}}\sqrt{\ln (r/r_o)}\frac{2e{V}_g}{m\ln ({\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_1/r_o)}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; f"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_f^{}{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {(r/r_o)}^{1/2}\mathrm{dr}$

$+\underset{R_1}{\overset{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_2/\cos \mathrm{\&theta;}}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}}{2\mathrm{\&pi;m}}\ln (r/r_o)\frac{2e{V}_g}{m}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; f"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_f^{}{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {\frac{r^2}{{\mathrm{<figure-callout\; id="1"\; label="r\; o"\; filenames="100311095637.png"\; state="\{\{state\}\}">r</figure-callout>}}_o}}^{1/2}\mathrm{dr}$

Therefore, filament and first grid assembly are departed from the 20-100mm distance with respect to second gate to the negative pole direction of power supply; Filament-first grid-second gate assembly is departed from the 20-350mm distance with respect to titanium foil to the negative pole direction of power supply; Suitably increase first grid diameter and grid voltage, reduce the bundle shift phenomenon that the spacing of the first grid and second gate can make electron gun cause and greatly weaken under " crossed electric and magnetic field " effect.

Intensifying ring 25 adopts single gap to accelerate electronics, and the scope in gap is 10cm.

For a wide beam source, one of most important key problem in technology is the uniformity that how to guarantee the radiation area bundle, the mode of operation of the choose reasonable negative electrode that the present invention finds, reduce that to make electron beam produce effect that serious skew causes and the density of reasonable disposition two ends filament etc. under the effect of " crossed electric and magnetic field " all be the performance that improves whole accelerator, must Adopts measure such as ejected beam spot shape, ejection efficiency, the uniformity etc.

Embodiment 2

Multi-filament broad beam electron curtain, as shown in Figures 1 to 4, comprise control system, electric power system 1, water-cooling system, nitrogen supply system and vacuum system 2, described electric power system 1 comprises high voltage source 11, head power supply 12 and isolating transformer 13, head power supply 12 is connected with higfh-tension ceramics 15 by high pressure lead-in 14, vacuum system 2 comprises electron gun 23, outer cylinder body 29,101 filaments 21, be vacuum chamber 20 between electron gun 23 and the outer cylinder body 29, the downside of electron gun 23 is provided with plate shaped second grid 24, second grid 24 is provided with second gate hole 241, be provided with titanium foil 26 and intensifying ring 25 under the second grid 24,203 cooling copper grids 27 that are parallel to each other are set on the titanium foil 26.

Filament 21 length are 11cm, be provided with columnar first grid 22 outside the filament 21, the end of first grid 22 is provided with back-moving spring, filament 21 with the tolerance of first grid 22 is ± 1mm, the downside half angle of first grid 22 is to be provided with the first grid hole 221 that electron beam passes through in 61 ° of scopes, the positive pole of head power supply links to each other with an end of filament 21, and the negative pole of head power supply links to each other with the other end of filament 21.To produce very large scattering when penetrating titanium foil owing to electron beam, even restraint when the incident titanium foil fully evenly as calculated, the effect of scattering will make the dosage of radiation area produce decline at two ends.Close to the irradiation face was healed from the paper tinsel film, dosage was healed large, and the border is steeper, and distribution is healed evenly, and homogeneity range is larger.By the distance between shortening paper tinsel film and the irradiation thing and through strengthening the length of electron gun and titanium foil, perhaps add the light orchid behind the titanium foil before the adjacent irradiation thing and can solve the inhomogeneous problem of dosage, still reduced the utilance of beam power.Therefore by encrypt the filament interval at two ends, cause titanium foil incident place two ends that larger beam current density is arranged, thereby reach the uniformity behind titanium foil.

The diameter of first grid 22 is 3.1cm, and the spacing between first grid 22 and the second grid 24 is 301mm.

Second gate hole 241 be width at 3mm, length is the rectangle perforate in the scope of 12mm.Have the rectangle perforate of drawing electron beam on the second grid 24, can reduce the titanium foil copper grid that beam divergence angle causes and cut the bundle rate.

Select the negative electrode mode of operation, and adopt space-charge-limited flow state or emission restriction stream, also be provided with dose monitoring system 28 on the outer cylinder body 29, dose monitoring system 28 is the measurement target of detected electrons stream.

Cooling copper grid 27 is the copper coin of certain radian arc, the height of cooling copper grid 27 is 12mm, and width is 1.4mm, and the distance between the adjacent cooling copper grid 27 is 2.4mm, cooling copper grid 27 is the water-cooled copper grid, and by cooling off titanium foil 26 to the mode of titanium foil 26 blowings.

The beryllium paper tinsel of titanium foil 26 for aluminizing, the thickness of titanium foil 26 is 15 μ m, width is 22cm.

Filament 21 and first grid 22 depart from 89mm with respect to second grid 24 to the negative pole direction of power supply, and filament 21, first grid 22, second grid 24 depart from 213mm with respect to titanium foil 26 to the negative pole direction of power supply.Because wire filament type electron gun is in the lower phenomenon that will cause that serious bundle is offset of " crossed electric and magnetic field " effect, and the having a strong impact on whole electron curtain device that cause of this phenomenon.The theoretical calculation formula of deriving:

${\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_2\&ap;\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_1+\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_2\&ap;\underset{r_o}{\overset{R_1}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}}{2\mathrm{\&pi;m}}\sqrt{\ln (r/r_o)}\frac{2e{V}_g}{m\ln ({\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_1/r_o)}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; f"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_f^{}{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {(r/r_o)}^{1/2}\mathrm{dr}$

$+\underset{R_1}{\overset{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_2/\cos \mathrm{\&theta;}}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}}{2\mathrm{\&pi;m}}\ln (r/r_o)\frac{2e{V}_g}{m}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; f"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_f^{}{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {\frac{r^2}{{\mathrm{<figure-callout\; id="1"\; label="r\; o"\; filenames="100311095637.png"\; state="\{\{state\}\}">r</figure-callout>}}_o}}^{1/2}\mathrm{dr}$

Therefore, filament and first grid assembly are departed from the 89mm distance with respect to second gate to the negative pole direction of power supply; Filament-first grid-second gate assembly is departed from the 213mm distance with respect to titanium foil to the negative pole direction of power supply; Suitably increase first grid diameter and grid voltage, reduce the bundle shift phenomenon that the spacing of the first grid and second gate can make electron gun cause and greatly weaken under " crossed electric and magnetic field " effect.

Intensifying ring 25 adopts single gap to accelerate electronics, and the scope in gap is 16cm.

For a wide beam source, one of most important key problem in technology is the uniformity that how to guarantee the radiation area bundle, the mode of operation of the choose reasonable negative electrode that the present invention finds, reduce that to make electron beam produce effect that serious skew causes and the density of reasonable disposition two ends filament etc. under the effect of " crossed electric and magnetic field " all be the performance that improves whole accelerator, must Adopts measure such as ejected beam spot shape, ejection efficiency, the uniformity etc.

Embodiment 3

Multi-filament broad beam electron curtain, as shown in Figures 1 to 4, comprise control system, electric power system 1, water-cooling system, nitrogen supply system and vacuum system 2, described electric power system 1 comprises high voltage source 11, head power supply 12 and isolating transformer 13, head power supply 12 is connected with higfh-tension ceramics 15 by high pressure lead-in 14, vacuum system 2 comprises electron gun 23, outer cylinder body 29,135 filaments 21, be vacuum chamber 20 between electron gun 23 and the outer cylinder body 29, the downside of electron gun 23 is provided with plate shaped second grid 24, second grid 24 is provided with second gate hole 241, be provided with titanium foil 26 and intensifying ring 25 under the second grid 24,423 cooling copper grids 27 that are parallel to each other are set on the titanium foil 26.

Filament 21 length are 14cm, be provided with columnar first grid 22 outside the filament 21, the end of first grid 22 is provided with back-moving spring, filament 21 with the tolerance of first grid 22 is ± 1mm, the downside half angle of first grid 22 is to be provided with the first grid hole 221 that electron beam passes through in 76 ° of scopes, the positive pole of head power supply links to each other with the mid point of filament 21, and the negative pole of head power supply links to each other with the other end of filament 21.To produce very large scattering when penetrating titanium foil owing to electron beam, even restraint when the incident titanium foil fully evenly as calculated, the effect of scattering will make the dosage of radiation area produce decline at two ends.Close to the irradiation face was healed from the paper tinsel film, dosage was healed large, and the border is steeper, and distribution is healed evenly, and homogeneity range is larger.By the distance between shortening paper tinsel film and the irradiation thing and through strengthening the length of electron gun and titanium foil, perhaps add the light orchid behind the titanium foil before the adjacent irradiation thing and can solve the inhomogeneous problem of dosage, still reduced the utilance of beam power.Therefore by encrypt the filament interval at two ends, cause titanium foil incident place two ends that larger beam current density is arranged, thereby reach the uniformity behind titanium foil.

The diameter of first grid 22 is 3.8cm, and the spacing between first grid 22 and the second grid 24 is 546mm.

Second gate hole 241 is the round hole of 5.4mm for diameter.Have the round hole of drawing electron beam on the second grid 24, can reduce the titanium foil copper grid that beam divergence angle causes and cut the bundle rate.

Select the negative electrode mode of operation, and adopt space-charge-limited flow state or emission restriction stream, also be provided with dose monitoring system 28 on the outer cylinder body 29, dose monitoring system 28 is the measurement target of detected electrons stream.

Cooling copper grid 27 is straight copper coin, the height of cooling copper grid 27 is 42mm, and width is 1.8mm, and the distance between the adjacent cooling copper grid 27 is 6.6mm, cooling copper grid 27 is the water-cooled copper grid, and by cooling off titanium foil 26 to the mode of titanium foil 26 blowings.

The beryllium paper tinsel of titanium foil 26 for aluminizing, the thickness of titanium foil 26 is 33 μ m, width is 31cm.

Filament 21 and first grid 22 depart from 138mm with respect to second grid 24 to the negative pole direction of power supply, and filament 21, first grid 22, second grid 24 depart from 303mm with respect to titanium foil 26 to the negative pole direction of power supply.Because wire filament type electron gun is in the lower phenomenon that will cause that serious bundle is offset of " crossed electric and magnetic field " effect, and the having a strong impact on whole electron curtain device that cause of this phenomenon.The theoretical calculation formula of deriving:

${\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_2\&ap;\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_1+\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="100311095637.png"\; state="\{\{state\}\}">z</figure-callout>}}_2\&ap;\underset{r_o}{\overset{R_1}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}}{2\mathrm{\&pi;m}}\sqrt{\ln (r/r_o)}\frac{2e{V}_g}{m\ln ({\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_1/r_o)}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; f"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_f^{}{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {(r/r_o)}^{1/2}\mathrm{dr}$

$+\underset{R_1}{\overset{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="100311095637.png"\; state="\{\{state\}\}">R</figure-callout>}}_2/\cos \mathrm{\&theta;}}{\&Integral;}}\frac{e{I}_f{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}}{2\mathrm{\&pi;m}}\ln (r/r_o)\frac{2e{V}_g}{m}\frac{e^2{\mathrm{<figure-callout\; id="2"\; label="I\; f"\; filenames="100311095637.png"\; state="\{\{state\}\}">I</figure-callout>}}_f^{}{\mathrm{\&mu;}}_{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="100311095637.png"\; state="\{\{state\}\}">o</figure-callout>}}^2}{4{\mathrm{\&pi;}}^2{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="100311095637.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}\ln {\frac{r^2}{{\mathrm{<figure-callout\; id="1"\; label="r\; o"\; filenames="100311095637.png"\; state="\{\{state\}\}">r</figure-callout>}}_o}}^{1/2}\mathrm{dr}$

Therefore, filament and first grid assembly are departed from the 20-100mm distance with respect to second gate to the negative pole direction of power supply; Filament-first grid-second gate assembly is departed from the 20-350mm distance with respect to titanium foil to the negative pole direction of power supply; Suitably increase first grid diameter and grid voltage, reduce the bundle shift phenomenon that the spacing of the first grid and second gate can make electron gun cause and greatly weaken under " crossed electric and magnetic field " effect.

Intensifying ring 25 adopts single gap to accelerate electronics, and the scope in gap is 31cm.

For a wide beam source, one of most important key problem in technology is the uniformity that how to guarantee the radiation area bundle, the mode of operation of the choose reasonable negative electrode that the present invention finds, reduce that to make electron beam produce effect that serious skew causes and the density of reasonable disposition two ends filament etc. under the effect of " crossed electric and magnetic field " all be the performance that improves whole accelerator, must Adopts measure such as ejected beam spot shape, ejection efficiency, the uniformity etc.

In a word, the above only is preferred embodiment of the present invention, and all equalizations of doing according to the present patent application claim change and modify, and all should belong to the covering scope of patent of the present invention.

Claims (10)

1. Multi-filament broad beam electron curtain, comprise control system, electric power system (1), water-cooling system, nitrogen supply system and vacuum system (2), it is characterized in that: described electric power system (1) comprises high voltage source (11), head power supply (12) and isolating transformer (13), head power supply (12) is connected with higfh-tension ceramics (15) by high pressure lead-in (14), vacuum system (2) comprises electron gun (23), outer cylinder body (29), 2-150 filament (21), be vacuum chamber (20) between electron gun (23) and the outer cylinder body (29), the downside of electron gun (23) is provided with plate shaped second grid (24), second grid (24) is provided with second gate hole (241), be provided with titanium foil (26) and intensifying ring (25) under the second grid (24), 2-600 cooling copper grid (27) that is parallel to each other is set on the titanium foil (26), the outer columnar first grid (22) that is provided with of filament (21), the positive pole of head power supply (12) links to each other with filament (21) one ends, the negative pole of head power supply (12) links to each other with the other end of filament (21), filament (21) and first grid (22) depart from a distance, filament (21) with respect to second grid (24) to the negative pole direction of head power supply (12), first grid (22), second grid (24) departs from a distance with respect to titanium foil (26) to the negative pole direction of head power supply (12).

2. Multi-filament broad beam electron curtain according to claim 1, it is characterized in that: described filament (21) length is 3-15cm, the end of first grid (22) is provided with back-moving spring, filament (21) is 1mm with the tolerance of first grid (22) distance, and the downside half angle of first grid (22) is to be provided with the first grid hole (221) that electron beam passes through in the 30-120 ° of scope.

3. Multi-filament broad beam electron curtain according to claim 2, it is characterized in that: the diameter of described first grid (22) is 1-4cm, the spacing between first grid (22) and the second grid (24) is 1-600mm.

4. Multi-filament broad beam electron curtain according to claim 2, it is characterized in that: described second gate hole (241) is the round hole of 2.5-6mm for diameter.

5. Multi-filament broad beam electron curtain according to claim 2 is characterized in that: described second gate hole (241) for width at 2.5-5mm, length is the rectangle perforate in the scope of 10-200mm.

6. Multi-filament broad beam electron curtain according to claim 1, it is characterized in that: select the negative electrode mode of operation, and adopt space-charge-limited flow state or emission restriction to flow, also be provided with dose monitoring system (28) on the outer cylinder body (29), dose monitoring system (28) is the measurement target of detected electrons stream.

7. Multi-filament broad beam electron curtain according to claim 1, it is characterized in that: described cooling copper grid (27) is straight or arc, the height of cooling copper grid (27) is 5-50mm, width is 0.6-2mm, distance between the adjacent cooling copper grid (27) is 0.5-7mm, cooling copper grid (27) is the water-cooled copper grid, and by cooling off titanium foil (26) to the mode of titanium foil (26) blowing.

8. Multi-filament broad beam electron curtain according to claim 1 is characterized in that: described titanium foil (26) adopts the beryllium paper tinsel of aluminizing to replace, and the thickness of the beryllium paper tinsel of aluminizing is 5-40 μ m, and width is 2-35cm.

9. Multi-filament broad beam electron curtain according to claim 2, it is characterized in that: described filament (21) and first grid (22) depart from 5-150mm with respect to second grid (24) to the negative pole direction of head power supply (12), and filament (21), first grid (22), second grid (24) depart from 5-350mm with respect to titanium foil (26) to the negative pole direction of head power supply (12).

10. Multi-filament broad beam electron curtain according to claim 1 is characterized in that: described intensifying ring (25) adopts single gap to accelerate electronics, and the scope in gap is 3-60cm.

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