JP2003504605A - Electron beam accelerator - Google Patents

Abstract

(57) Abstract The electron accelerator 10 includes a vacuum chamber 46 having an electron beam emission window 24. The radiation window 24 is formed of a metal foil bonded to the vacuum chamber 104 by metal contact, and hermetically seals the both. The thickness of the radiation window 24 is less than about 12.5 μm. The vacuum chamber 104 is hermetically sealed and the interior is permanently maintained at a self-holding vacuum. The electron generator 31 is placed in the vacuum chamber 104 and generates electrons. A housing 30 surrounds the electron generator 31. The housing 30 has electron transmission areas 34 and 35 formed between the electron generator 31 and the emission window 24. When a voltage is applied between the housing 30 and the emission window 24, the electrons 56 are emitted. From the electron generator 31 to the outside of the radiation window 24 as an electron beam 58.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION

Electron beams are used in many industrial processes such as drying and curing inks, paints and coatings. Electron beams are used to sterilize liquids, gases and surfaces, as well as to clean up hazardous waste.

Conventional industrial electron beam devices include an electron beam accelerator that irradiates an electron beam onto the material to be processed. The accelerator has a large vacuum chamber surrounded by lead and contains an electron generating filament or a filament powered by a filament power supply. During operation, the vacuum chamber is continuously evacuated by a vacuum pump. The filament is surrounded by a housing, which has a grid of openings facing a metal foil electron emission window located on one side of the vacuum chamber. A high voltage is applied between the filament housing and the emission window by a high voltage power supply. The electrons generated from the filament are accelerated and pass from the filament as an electron beam through the opening lattice of the housing and are emitted to the outside through the emission window. A power source for the radiating device is generally provided to flatten the electric field lines in the region between the filament and the radiating window. This prevents the electrons in the electron beam from being concentrated in the center of the beam as shown in graph 1 of FIG. 1, and disperses the electrons uniformly over the entire width of the beam as shown in graph 2 of FIG. .

The drawback of using electron beam technology in the industrial field is that the conventional electron beam equipment is complicated and, in addition, it requires highly trained personnel in vacuum and accelerator technology to maintain the equipment. Is what you need. For example, during normal operation, both the filament and the metal foil of the electron beam emitting window need to be regularly replaced. Accelerators are very large and heavy (typically 20-30 inches in diameter (508-76 inches).
2mm), 4-6 feet long (1220-1830mm), weighs a few thousand pounds (
About 1,000 to several thousand kg)), such maintenance work needs to be performed on site.

Replacing the filament and the electron beam emission window requires opening the vacuum chamber, which causes contaminants to enter the vacuum chamber. This exchange requires a long down time. This is because, if the filament and the metal foil of the radiation window are exchanged, the accelerator can be operated only after the accelerator is evacuated and adjusted for high voltage operation. This adjustment requires power from a high voltage power supply, which is gradually ramped over time to incinerate contaminants in the vacuum chamber and on the surface of the radiant window that enter when the chamber is opened. To raise. Depending on the degree of contamination, this treatment may be 2-1
It takes 0 hours. If the radiation window leaks along the way, it must be repaired, further extending the processing time. Ultimately, every year or every two years, it is necessary to replace the accelerator high voltage insulator and disassemble the entire accelerator. The time required for this treatment is about 2 to 4 days. As a result, the manufacturing process requiring electron beam emission is interrupted for a long period of time when the filament, electron beam emitting window metal foil, or high voltage insulator needs to be replaced.

[0005]

[Outline of the Invention]

The present invention provides a small, simple electron accelerator for an electron beam device, which facilitates maintenance work on the electron beam device and facilitates maintenance work by personnel highly trained in vacuum and accelerator technology. Eliminating the need.

In a preferred embodiment of the present invention, an electron accelerator comprising a vacuum chamber having an electron beam emission window is provided. The radiation window is formed of a metal foil bonded in metal contact with the vacuum chamber, and hermetically seals the both. The thickness of the radiation window is about 12.
It is less than 5 μm. The vacuum chamber is hermetically sealed to maintain a permanent self-holding vacuum inside. An electron generator is placed in the vacuum chamber and produces electrons. A housing surrounds the electron generator. The housing has an electron transmissive region formed on its wall between the electron generator and the emission window, and emits electrons from the electron generator when a voltage is applied between the housing and the emission window. It accelerates as an electron beam out of the window.

In a preferred embodiment, the series of openings in the housing form an electron transmissive region.
Preferably, the radiation window is formed of titanium foil about 8-10 μm thick and is held by a support plate having a series of holes through which electrons can pass. The configuration of the holes in the support plate can be varied to change the electron transmission across the support plate to produce an electron beam with the desired variable density profile. Generally, the outer edge of the radiation window is brazed, welded, or joined to the vacuum chamber to hermetically seal the vacuum chamber.

[0008] Preferably, the vacuum chamber comprises an elongated ceramic member. In one preferred embodiment, the elongated ceramic member is corrugated, which allows high voltages to be used. A ring-shaped spring member is coupled between the radiation window and the corrugated ceramic member to compensate for the difference in expansion coefficient.

In another preferred embodiment, the elongated ceramic member has a smooth surface,
A metal shell surrounds the ceramic member. The ceramic member includes a frustoconical hole through which an electrical lead extends to power the electron generator. A flexible or flexible insulating plug surrounds the electrical lead, the plug having a frustoconical surface that closely adheres to and seals the inner surface of the frustoconical hole. A retaining cap is secured to the shell to retain the plug in the frustoconical hole.

The present invention also provides an electron accelerator including a vacuum chamber having an electron beam emission window. An electron generator is located within the vacuum chamber and produces electrons. A housing surrounds the electron generator and has an electron transmissive region formed within the housing between the electron generator and the emission window. When a voltage is applied between the housing and the emission window, the electron transmission region accelerates electrons from the electron generator to the outside of the emission window as an electron beam. The housing is provided with a passive electric field line shaper (shaping means) to flatten the electric field line between the electron generator and the emission window to make the lateral electron distribution of the electron beam uniform.

Preferably, the electron transmissive region is first in the housing between the electron generator and the emission window.
, While the passive electrical line shaper comprises a second and third series of openings formed on opposite sides of the electron generator housing.

The present invention provides a compact, interchangeable, modular electron beam accelerator. When the filament or electron beam emission window needs to be replaced, the entire accelerator is replaced, which significantly reduces the downtime of the electron beam device. It also does not require skilled personnel for vacuum and accelerator technology to maintain the device. It also eliminates the need for field replacement of the high voltage insulation. Further, the electron beam accelerator of the present invention has a small number of components and requires less electric power as compared with the conventional electron beam accelerator, thus realizing low cost, simplicity and high efficiency. Space-saving devices, such as small presses, or line
Suitable for use in equipment such as line web sterilization and curing between stations.

The foregoing and other objects, features, and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments of the invention illustrated in the accompanying drawings. In the drawing,
The same reference numerals refer to the same parts in different drawings. The drawings are not necessarily to scale and emphasis is placed on illustrating the principles of the invention.

[0014]

Detailed Description of the Preferred Embodiments

In FIGS. 2 and 3, the electron beam accelerator 10 is a replaceable modular accelerator and is incorporated into an electron beam device housing (not shown). The accelerator 10 includes an elongated, generally cylindrical, bisection outer shell 14 that is sealed at both ends. The proximal end of the outer shell 14 is closed by a proximal end cap 16 welded to the outer shell. Preferably, outer shell 14 and end cap 16 are each made of stainless steel, although alternative methods may be made of other suitable metals.

The tip of the accelerator is closed with an electron beam emitting window film made of titanium foil, which is brazed along the outer edge 23 to the stainless steel tip end cap 20. The end cap 20 is welded to the outer shell 14. The radiation window 24 is generally about 6-12 μm thick, and more preferably about 8 μm.
10 to 10 μm. Alternatively, the radiating window 24 can be made of any other suitable metal foil, such as a suitable non-metallic, low density material such as magnesium, aluminum, or ceramic. Further, the radiating window 24 may be welded or joined to the end cap 20. A rectangular support plate 22 having holes or openings 22a through which electrons pass is bolted to the end cap 20 using bolts 22b to help hold the emission window 24. Support plate 22 is preferably made of copper for heat dissipation, but in the alternative, it may be made of other suitable metals such as stainless steel, aluminum, or titanium. The hole 22a in the support plate 22 has a diameter of about 1/8 inch (
3.2 mm), providing an aperture of about 80% so that the electrons pass through the emission window 24.

The end cap 20 includes a cooling passage 27, through which a cooling liquid is pumped to cool the end cap 20, the support plate, and the radiation window 24.
Coolant enters from the inlet (inlet) 25a and the outlet (outlet) 25b.
Get out of. The inlet 25a and the outlet 25b are connected to the electron beam coolant supply port and the return port of the electron beam apparatus housing. The refrigerant supply and return ports are equipped with "O" ring seals for sealing the inlet 25a and outlet 25b. The accelerator 10 has a diameter of about 12 inches (305 mm),
It is 20 inches (508 mm) long and weighs about 50 pounds (23 kg).

A high voltage electrical connection receptacle 18 coupled to the connector 12 of the high voltage power cable is attached to the proximal end cap 16. The high voltage cable is shown in Figure 3.
The electric power from the high voltage power source 48 and the filament power source 50 is supplied to the accelerator 10.
The high voltage power supply 48 preferably supplies about 100 kV, but in the alternative it may be scaled by the thickness of the radiation window 24. The filament power supply 50 preferably supplies about 15V. The two electrical leads 26a / 26b shown in FIG. 2 extend downwardly from the receptacle 18 to define a disk-shaped high voltage ceramic insulator 28 that divides the accelerator 10 into an upper insulation chamber 44 and a lower vacuum chamber 46. Penetrates.
For joining the ceramic insulator 28 to the outer shell, first, the insulator 28 is KOVA.
It is brazed to a metal intermediate ring 29 having the same expansion coefficient as the insulator 28 such as R (registered trademark). The intermediate ring 29 is then brazed to the outer shell 14. The upper chamber 44 is filled with an insulating medium such as SF ₆ gas after evacuation,
Alternatively, it may be filled with oil or a solid insulating medium. Gaseous and liquid insulating media can be filled and drained through the stop valve 42.

The electron generator 31 is located in the vacuum chamber 46 and is composed of three 8 inch (203 mm) long tungsten filaments 32 (FIG. 4) electrically connected in parallel. desirable. Alternatively, two filaments 32 can be used. The electron generator 31 is surrounded by a stainless steel housing 30. The filament housing 30 has a series of grid-like openings 34 in the flat bottom wall 33 and a series of openings 35 in the four side walls of the housing 30. These openings 34, 35 are electron passage regions. Is formed. Filament 32
Is preferably located in the housing 30 approximately midway between the bottom wall 33 and the top wall of the housing 30. The aperture 35 does not extend substantially above the filament 32.

The electrical leads 26 a and wires 52 shown in FIG. 3 electrically connect the filament housing 30 to the high voltage power supply 48. Electrical lead 26b passes through hole 30a in filament housing 30 to electrically connect filament 32 to filament power supply 50. The emission window 24 is electrically grounded and a high voltage is applied between the filament housing 30 and the emission window 24.

The vacuum chamber 46 is provided with an inlet (exhaust port) 39 shown in FIG. 2 for exhausting the vacuum chamber 46. The inlet 39 has a stainless steel outer pipe 36 welded to the outer shell 14 and a sealable copper pipe 38 brazed to the outer pipe 39. After evacuating the vacuum chamber, the pipe 38 is pressure cold pressed to form a seal 40 and hermetically seal the vacuum chamber 46.

In use, the accelerator 10 is built into the electron beam device and electrically connected to the connector 12. The housing of the electron beam apparatus incorporates a lead enclosure surrounding the accelerator 10. Filament 32 is powered by filament power supply 50 (AC or DC) and heated to a maximum of about 4200 ° F. causing filament 32 to generate free electrons. The high voltage between the filament housing 30 and the emission window 24 applied from the high voltage power supply 48 of FIG. 3 accelerates the free electrons 56 on the filament 32 shown in FIG. It radiates to the outside through the opening 34 of the housing 30 and the radiation window 24 (FIG. 3).

The side openings 35 generate a weak electric field around it, which causes the high-voltage electric field lines 54 between the filament 32 and the radiation window 24 to be flat against the plane of the bottom wall 33 of the housing 30. Convert (parallelize to this plane). By flattening the high voltage electric field lines 54, the electrons 56 of the electron beam 58 do not focus in the central position as shown in Graph 1 of FIG. Is emitted. As a result, the electron beam 58 has a width of about 2 inches (50.8 mm) and a length of about 8 inches (20 mm) with a profile similar to that of graph 2 of FIG.
3mm) wide beam. The thin high-density electron beam in graph 1 of FIG. 1 is not preferable because it burns out the hole penetrating the radiation window 24.

To further illustrate the function of the side openings 35, FIG. 5 shows the housing 30 without the side openings. As can be seen from FIG. 5, when the side opening 35 is omitted, the electric field lines 54 curve upward in an arc shape. The electrons 56 travel so as to be substantially orthogonal to the electric field lines 54, so that the electrons 56 are focused into a narrow electron beam 57. In contrast, in FIG.
The electric field lines 54 are flattened and the electrons 56 are broad and substantially unfocused electron beam 58.
Proceed in the state of. Therefore, in the conventional accelerator, it was necessary to flatten the high-voltage electric field lines by using the power source of the high-voltage extractor to uniformly disperse the electrons in the lateral direction of the electron beam. In the present invention, by providing the opening 35, the same result can be obtained by a simple and inexpensive method.

When replacing the filament 32 or emission window 24 of FIG. 2, all that is required is to remove the entire accelerator 10 from the electron beam device housing and replace it with a new accelerator 10. Since the new accelerator 10 has been previously conditioned for high voltage operation, the electron beam system has only a few minutes of downtime. The operator of the electron beam system does not need to be highly proficient in the maintenance of vacuum or accelerator technology as only a single part needs to be replaced. Furthermore, since the accelerator 10 is small and lightweight, it can be replaced by one person.

To recondition the old accelerator 10, it is desirable to send the old accelerator to another location, such as a company specializing in vacuum technology. First, the radiation window 24 and the support plate 2
2 is removed and the vacuum chamber 46 is opened. The housing 30 is then removed from the vacuum chamber 46 and the filament 32 is replaced. Upper chamber 4 if required
The insulating medium in 4 is discharged from a valve 42 provided in the outer shell 14. afterwards,
Reinstall the housing 30 in the vacuum chamber. End the support plate 22
The cap 20 is fixed with a bolt, and the radiation window 24 is replaced with a new one. The outer edge 23 of the new radiating window 24 is brazed to the end cap 20 to form a sealing structure. Since the radiation window 24 covers the support plate 22, the bolts 22b, and the bolt holes, there is no leakage even without an "O" ring, and the window 24 serves an auxiliary function of sealing the front surface of the support plate 22. There is. Remove the copper pipe 38 and replace it with a new copper pipe 36
Braze to. These conditioning operations are performed in a controlled, clean air environment to prevent contamination of the vacuum chamber and radiation windows.

By assembling the accelerator 10 in a clean environment, the radiating window 24 can easily be 8-1.
It can be as thin as 0 μm or as thick as 6 μm. The reason is that dust or other contaminants are prevented from accumulating on the radiation window 24 between the radiation window 24 and the support plate 22. Such pollutants are emitted through the emission window 24 with a thickness of less than 12.5 μm.
Make a hole in. In contrast, the electron beam emission window of a conventional accelerator requires a thickness of 12.5 to 15 μm because it is assembled in a dusty site during maintenance work.
The thickness of the radiation window of 12.5 to 15 μm is sufficient to prevent dust from perforating the radiation window.

Since the emission window 24 of the present invention is generally thinner than the emission window of a conventional accelerator, the power required only to accelerate electrons to pass through the emission window 24 is significantly small. For example, in a conventional accelerator, about 150 kV is required to accelerate an electron through an emission window having a thickness of 12.5 to 15 μm. On the other hand, in the present invention, the thickness is 8 to 1
About 80 to 125 kV is required to penetrate the 0 μm emission window.

As a result, the accelerator 10 is more efficient than conventional accelerators in producing an equivalent electron beam. Further, since the low voltage is sufficient, the accelerator 10 can be made small,
A smaller disk-shaped insulator 28 can be used than the cylindrical or conical insulator used in conventional accelerators. The reason why the accelerator 10 can be made smaller than the conventional accelerator is
Because the voltage is low, the components of the accelerator 10 can be assembled closer together. By controlling the inside of the vacuum chamber to a clean environment, the components can be installed closer together. In addition to operating at high voltage, conventional accelerators also have a lot of contaminants in the accelerator, which necessitates spacing between components to prevent arcing between them. In fact, in conventional accelerators, contaminants from the vacuum pump enter the accelerator during use.

Next, the vacuum chamber 46 is evacuated from the inlet 39, and the tube 38 is cold-pressed and sealed. When the vacuum chamber 46 is hermetically sealed, the vacuum chamber 46 remains permanently in vacuum and the vacuum pump need not be activated. This makes the accelerator 10 of the present invention simple and inexpensive to operate. Thereafter, the accelerator 10 is preconditioned for high voltage operation. In this adjustment, the accelerator 10 is connected to an electron beam device and the voltage is gradually increased to incinerate all contaminants in the vacuum chamber 46 and on the radiation window 24. All the molecules remaining in the vacuum chamber 46 are ionized by the high voltage and / or the electron beam and accelerated toward the housing 30. The ionized molecules collide with the housing 30 and are trapped on the surface of the housing 30, and as a result, the degree of vacuum is further increased. The vacuum chamber 46 can also be evacuated while the accelerator 10 is being preconditioned for high voltage operation. The accelerator 10 is removed from the electron beam system and stored for reuse.

FIG. 6 shows a system including three accelerators 10a, 10b, 10c. These accelerators irradiate the electron beam across the entire width of the moving product 62 without any gap,
They are arranged in a zigzag pattern relative to each other. Irradiate with the electron beam 60. Since the electron beams of the respective accelerators 10a, 10b, 10c are smaller than the outer diameter of one accelerator, even if the three are arranged side by side, the electron beam 60 cannot be irradiated over the entire width of the product 62. Instead, the accelerator 10b is arranged along the moving direction of the product 62, with a slight lateral shift to the accelerators 10a and 10c. As a result, the side edges of the respective electron beams 60 are laterally aligned with each other without a gap. As a result, as shown in the figure, the moving product 62 is irradiated stepwise with the electron beam 60 on the entire surface. Although three accelerators are shown, as an alternative method, four or more accelerators 10 are arranged in a zigzag to irradiate a wider product, or two accelerators 10 are arranged in a zigzag to produce a narrower product. Can also be irradiated.

7 and 8 show another preferred method of electrically connecting the leads 26a and 26b to the filament housing 30 and filament 32. Lead wire 26a
Is fixed to the upper wall of the filament housing 30. Three filament brackets 102 extend downwardly from the top wall of filament housing 30.
A filament mount 104 is attached to each bracket 102. Insulating block 110 and filament mount 108 are mounted on the wall of filament housing 30 opposite filament mount 104. Filament 32 is mounted stretched between filament mounts 104 and 108. . A flexible lead 106 electrically connects the lead 26b and the filament mount 108. The filament bracket 102 has a spring effect to compensate for the expansion and contraction of the filament 32 during use. The cylindrical bracket 112 supports the housing 30 instead of the leads 26a / 26b.

The filament arrangement 90 shown in FIG. 9 is another preferred method of electrically connecting multiple filaments to broaden the width of the electron beam beyond that provided by a single filament. The filaments 92 are arranged in parallel and electrically connected to each other in series by electrical leads 94.

The filament arrangement 98 shown in FIG. 10 shows a series of filaments 97, which are arranged in parallel and electrically connected in parallel by two electrical leads 96. This filament arrangement 98 also has the effect of widening the width of the electron beam.

Accelerator 70, shown in FIG. 11, is another preferred embodiment of the present invention. The accelerator 70 generates an electron beam in a direction at an angle of 90 degrees with respect to the electron beam generated by the accelerator 10 in FIG. Unlike the accelerator 10, the accelerator 70 has a filament 78.
Are not parallel to the long axis A of the vacuum chamber 88, but are parallel to each other. Further, the radiating window 82 does not allow the outer chamber 72 to be replaced by the vacuum chamber end cap 74.
Are arranged in parallel with the long axis A. The radiation window 82 is held by a support plate 80 attached to the side wall of the outer shell 72. Elongated filament housing 7
5 surrounds the filament 78, and has one side wall 76 of the housing 75 with the lattice-shaped openings 34 opened in the direction orthogonal to the major axis A. Filament housing 75
The side opening 35 is open in a direction perpendicular to the opening 34. End cap 74
Closes the end of the vacuum chamber. The accelerator 70 is suitable for irradiating a large area with an electron beam without using a plurality of zigzag-arranged accelerators (FIG. 6), and is also suitable for use in a narrow space. The accelerator 70 is about 3-4 feet long (900-
1200 mm) and can be arranged in a zigzag to realize a wider irradiation range.

The accelerator 100 shown in FIG. 12 represents yet another embodiment of the present invention. Accelerator 10
0 comprises a generally cylindrical outer shell 102 formed of a ceramic material having a vacuum chamber 104 therein. The outer shell 102 has a closed proximal end 106,
It has an open tip 118 opposite it. The outer surface of the outer shell 102 is provided with a series of corrugations 102a that allow the accelerator 100 to operate at higher voltages than if the outer shell 102 were a smooth surface. The open end 118 has a portion with a smooth outer surface. The metal end cap 110 is the outer shell 1
It encloses and covers the smooth open tip 118 of 02 to seal the vacuum chamber 104.

The end cap 110 with the radiating window 24 is brazed to an intermediate annular metal spring 108, which is brazed to the outer shell 102. Thus
An annular spring 108 is engaged between the ceramic member end cap 110 and the radiation window 24, and the spring 108 seals the vacuum chamber 104. Spring 1
08 allows the ceramic outer shell 102 and the end cap 110 to have different radial and axial expansion and contraction rates while maintaining a hermetic seal therebetween. Spring 108 is end cap 1
This is accomplished by spacing 10 slightly away from the outer shell 102 and further comprising an elastic material. The spring 108 is an annular inner V-shaped ridge 108.
a, whose inner legs are brazed to the outer shell 102. An annular outer flange 108b projects radially outward from the V-shaped raised portion 108a,
It is brazed to the cap 110.

The end cap 110 comprises an outer annular wall 112 and an inner annular wall 114 forming an annular gap 116 between which the open tip 118 of the outer shell 102 enters. . Gap 116 is wider than the wall thickness of tip 118, which causes tip 118 to be spaced from the sides and bottom of gap 116,
Around the tip 118, a space or passage is formed for connecting the vacuum chamber 104 to the inlet 39, as indicated by the gaps 116a, 116b, 116c. By this passage, the vacuum chamber 104 is exhausted through the inlet 39. The inlet 39 is brazed or welded to the outer annular wall 112 of the end cap 110 and extends therethrough.

The end cap 110 also includes a support plate 22 having a through hole 22a.
The radiant window 24 is bonded to the end cap on the support plate 22, generally by heating and pressing, or by brazing or welding. A cover plate 120 having a central opening 120a covers and protects the radiation window 24. The end cap 110 has a cooling passage 27 similar to the passage shown in FIG. Although the end cap 110 is shown as a single piece, in the alternative it could be formed from multiple parts. For example, the support plate 22 and the annular wall 114 may be separate components. Further, the annular wall 114 can be omitted if desired.

The filament housing 30 is contained within a vacuum chamber 104, the outer shell 102.
Is located just below the closed proximal end 106 of the. Electrical leads 26a / 26b extend through the proximal end 106 of the outer shell 102 and are sealed thereto. The filament 30 and the electron generator 31 are the same as those shown in FIG. Although the opening 35 is shown in the filament housing 30, this opening may be omitted in alternative methods.

The accelerator 130 shown in FIG. 13 is yet another preferred accelerator. Accelerator 130
Comprises a metallic outer shell 122 which surrounds a ceramic inner shell 124 having a smooth outer surface. Preferably, the open tip 118 of the inner shell 124 extends to the support plate 22, thereby forming an annular wall (ceramic member) 136 of ceramic material between the vacuum chamber 134 and the outer shell. Alternatively, the tip 118 may be terminated prior to reaching the support plate 22. The inner shell 124 has a frustoconical opening 124a extending through a proximal end 119 opposite the distal end 118. An electrical lead 128 having a connector 138 extends through the frustoconical opening 124a and powers the filament housing 30 and electron generator 31 via electrical leads 26a / 26b.

Filament housing 30 and electron generator 31 are similar to those of accelerator 100 (FIG. 12). The electrical lead 128 extends through a central opening 126a of a polymeric insulating flexible plug 126. The insulating plug 126 includes a mating frustoconical outer surface 126b for sealingly sealing the frustoconical hole 124a. Retaining cap 140 fixed to the outer shell 122
Applies an axial compressive force to the plug 126, causing the plug 126 to have a frustoconical hole 124a.
Of the plug 126 against the outer circumference of the electrical lead 128 to provide a tight seal between the electrical lead 128 and the plug 126. Preferably the plug 12
6 is made from ethylene propylene rubber having an electrical resistance of 10 ¹⁴ to 10 ¹⁵ Ω-cm. Also, the inner shell 124 preferably has an electrical resistance of 10 ¹⁴ Ω-cm.

FIG. 14 shows a preferred filament 32 for the electron generator used in accelerators 100 and 130 (FIGS. 12 and 13). The filament 32 is formed into a substantially W shape by a series of curved lines. This allows the filament 32 to expand and contract during operation without the need for support by elastic or spring-loaded members. The ends of the filament 32 can be bent into hairpins as shown in FIG. 14 to insert the ends into openings or slots in the electrical leads 26a, 26b. Multiple filaments 32 can be used if desired.

As shown in FIG. 15, the holes 22a of the support plate 22 in the accelerators 100 and 130 (FIGS. 12 and 13) are filled or packed, if necessary, so that the resulting emitted electron beam traverses the beam. It may have a variable density profile along the direction. Alternatively, instead of filling or packing the holes 22a, the holes 22a can be arranged in the support plate 22 so as to form a desired pattern of hole distribution during manufacture. Although a particular shape 142 is shown in FIG. 15, any desired shape can be formed.

As shown in FIG. 16, extension nozzles 144 can be secured to accelerators 100 and 130 (FIGS. 12 and 13) if desired. In this case, the radiation window 24 can be arranged at the tip of the nozzle. Nozzle 144 can be inserted into narrow openings such as cups and bottles and used to sterilize the interior.

The electron accelerator of the present invention is used for sterilization of liquid, gas (such as air) or surface,
Suitable for purification of medical products, food, hazardous medical waste and hazardous waste. Other applications include ozone generation, fuel atomization, and chemical bonding of materials. Further, the electron accelerator of the present invention can be used to cure inks, coatings, adhesives and sealants. In addition, materials such as polymers can be cross-linked with electron beam irradiation to improve structural properties.

The series of openings 35 in the filament housing 30 form a passive electric field line shaper that modifies the shape of the electric field lines, in particular a flattener that flattens the electric field lines. The term "passive" means that the electric field lines are formed without the need for a separate extractor power supply. Further, the electric field lines can be formed by using a plurality of filaments. In addition, barriers or passive electrodes can be placed between the filaments to form the electric field lines in a different shape. Multiple filaments, barriers or passive electrodes can be used as a flattener to flatten and otherwise shape the electric field lines.

While the invention has been illustrated and described by way of preferred embodiments, those skilled in the art will appreciate that various shapes and details can be changed without departing from the spirit and scope of the invention as defined in the appended claims. It will be appreciated that modifications of the above are feasible.

For example, although certain embodiments of the present invention have been described as having multiple filaments, alternative methods may use only one filament. further,
The outer shells (except the ceramic outer shell 102), end caps, and filament housing are preferably made of stainless steel,
Alternatively, other suitable metals can be used, such as titanium, copper, or KOVAR®. The end caps 16, 20 are typically the outer shell 14
However, brazing is also possible instead. The holes 22a of the support plate 22 can have a non-circular shape like a slot. The dimensions of filament 32 and the outer diameter of accelerator 10 can be varied depending on the application. Also, other suitable materials such as glass can be used as the insulator 28.

Preferably, the thickness of the titanium emission window is less than 12.5 μm (6-12 μm), but can be greater than 12.5 μm for specific applications if desired. 12.5
For radiation windows thicker than μm, the high voltage power supply should supply approximately 100-150 kV. If the emission window is made of a material that is lighter than titanium (such as when using aluminum), it is possible to obtain the same electron beam characteristics while making the emission window thicker than the corresponding titanium emission window. it can. Preferably, the accelerator has a cylindrical cross section, but it may have any other suitable shape, such as a rectangular or elliptical cross section. If the accelerator of the present invention is manufactured in a large amount to reduce the cost, it can be used as a disposable unit. The receptacles 18 of the accelerators 10, 70 can also be arranged perpendicular to the long axis A to save space. Finally, the various structures of the different embodiments of the present invention can be combined or omitted.

[Brief description of drawings]

FIG. 1 is a characteristic diagram in which a graph showing a distribution of electrons in a narrowed electron beam and a graph showing a state in which the electrons are uniformly distributed in the entire width of the electron beam are overlapped.

[Fig. 2]   It is a side sectional view of an electron beam accelerator of the present invention.

[Figure 3]   FIG. 3 is a schematic diagram showing power connection of the accelerator of FIG. 2.

[Figure 4]   FIG. 3 is an end cross-sectional view of the filament housing showing electric field lines.

FIG. 5 is an end cross-sectional view of the filament housing showing the electric field lines without the side openings 35.

[Figure 6]   FIG. 3 is a plan view of a system incorporating multiple electron beam accelerators.

FIG. 7 is a schematic end cross-sectional view of a filament housing showing another preferred method of electrically connecting filaments.

[Figure 8]   FIG. 8 is a schematic bottom cross-sectional view of FIG. 7.

[Figure 9]   FIG. 6 is a schematic view of another preferred filament arrangement.

[Figure 10]   FIG. 6 is a schematic view of yet another preferred filament arrangement.

FIG. 11   FIG. 6 is a side sectional view of another preferred electron beam accelerator.

[Fig. 12]   FIG. 7 is a side sectional view of yet another preferred electron beam accelerator.

[Fig. 13]   FIG. 7 is a side sectional view of yet another preferred electron beam accelerator.

FIG. 14   FIG. 6 is a bottom view of another preferred filament arrangement.

FIG. 15: To produce an electron beam with a lateral variable density profile of the beam,
FIG. 6 is a plan view showing a support plate having a pattern of filled holes.

FIG. 16   It is a side view of an extension nozzle.

[Explanation of symbols]

22 ... Support plate, 26a, 26b ... Electric lead wire, 24 ... Radiation window, 30 ... Housing, 31 ... Electron generator, 34, 35 ... Opening (electron transmission area), 35 ... Electric field line shaper, 56 ... Electron, 58 ... electron beam, 100, 130 ... electron accelerator, 102
, 124, 136 ... Ceramic member, 104, 134 ... Vacuum chamber, 122 ...
Outer shell, 124a ... frustoconical hole

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, MZ, SD, SL, SZ, TZ, UG , ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, BZ, C A, CH, CN, CR, CU, CZ, DE, DK, DM , DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, K E, KG, KP, KR, KZ, LC, LK, LR, LS , LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, RO, R U, SD, SE, SG, SI, SK, SL, TJ, TM , TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW (72) Inventor Ferris Kenneth Pee             Vermont, United States 05672,             Storwe, Lower Sanborn Road               235

Claims (14)

[Claims] 1. A vacuum chamber comprising an elongated ceramic member having an electron beam emission window, the emission window being formed from a metal foil bonded to the vacuum chamber in metal contact to provide a hermetic seal therebetween. And the thickness of the radiation window is about 12
． A vacuum chamber of less than 5 μm, hermetically sealed so as to maintain a permanent self-holding vacuum therein; an electron generator disposed in the vacuum chamber to generate electrons; and a housing surrounding the electron generator. And having an electron transmissive region formed between the electron generator and the emission window, wherein electrons are emitted from the electron generator when a voltage is applied between the housing and the emission window. An electron accelerator including a housing that accelerates an electron beam toward the outside of the window. 2. The electron accelerator according to claim 1, wherein the elongated ceramic member is corrugated. 3. The electron accelerator according to claim 2, further comprising an annular spring member engaged between the radiation window and the ceramic member. 4. The electron accelerator of claim 1, wherein the vacuum chamber further comprises a metal shell surrounding the ceramic member. 5. The electric ceramic wire of claim 4, wherein the ceramic member includes a frustoconical hole, the electron accelerator further extending through the frustoconical hole to provide electrical power to the electron generator. A flexible insulating plug surrounding the electronic lead and having a frustoconical surface for sealing the frustoconical hole, and a retaining cap secured to the shell to retain the plug within the frustoconical hole. Electron accelerator. 6. The electron accelerator according to claim 1, wherein the electron transmissive region comprises a series of openings in the housing. 7. The electron accelerator according to claim 1, wherein the radiation window is formed of a titanium foil having a thickness of about 8 to 10 μm. 8. The support plate according to claim 1, further comprising a support plate having a series of through holes for holding the emission window and allowing electrons to pass therethrough, wherein the series of holes includes the electron beam having a variable density profile. An electron accelerator arranged to vary electron transparency across the support plate to form. 9. A vacuum chamber comprising an elongated ceramic member having an electron beam emission window, said emission window being formed from a metal foil bonded to said vacuum chamber in metal contact to provide a hermetic seal therebetween. And the thickness of the radiation window is about 12
． Providing a vacuum chamber of less than 5 μm and hermetically sealed so as to maintain a permanent self-holding vacuum therein; generating electrons using an electron generator disposed in the vacuum chamber; Enclosing the electron generator with a housing, the housing having an electron transmissive region formed between the electron generator and the emission window, when a voltage is applied between the housing and the emission window. Accelerating the electrons from the electron generator toward the outside of the emission window as an electron beam, and accelerating the electrons. 10. The method of claim 9, further comprising corrugating the elongated ceramic member. 11. The method of claim 10, further comprising engaging an annular spring member between the radiation window and the ceramic member. 12. The method of claim 9, further comprising surrounding the ceramic member with a metal shell. 13. The method of claim 12, wherein the ceramic member includes a frustoconical hole and the method further comprises extending an electrical lead through the frustoconical hole to power the electron generator. Surrounding the electrical lead with a flexible insulating plug having a frustoconical surface for sealing the frustoconical hole, the plug being fitted into the frustoconical hole with a retaining cap secured to the shell. Retaining. 14. The method of claim 9, further comprising holding the emission window with a support plate, the support plate having a series of holes through the plate for passing the electron beam, The method wherein the series of holes are arranged to vary electron transparency across the support plate to form the electron beam with a variable density profile.