JP2003225287A - Method and system for sterilization - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a system for sterilization which enable effective sterilization of an object by using an electron beam, without deteriorating the object and without using a large-scale installation. <P>SOLUTION: The system for sterilization is equipped with a conveyance line 1 which conveys a plurality of objects A consecutively and an electron beam irradiation device 2 which shines the electron beam onto the objects A conveyed on the conveyance line 1, and it sterilizes the surface of the object by the irradiation of the electron beam. The accelerating voltage of the electron beam of the electron beam irradiation device 2 is lower than 150 kV and the electron beam is emitted from the device 2 so that the absorbed dose of the electron beam measured by using a dose measuring film is 5-200 kGy. The conveying speed of the conveyance line 1 to 300 m/min or below, and when the value of the product of the absorbed dose of the electron beam and the conveying speed is made to be Z, the value of Z is in the range of 50-20,000 kGy m/min. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sterilizing method and a sterilizing system for sterilizing or sterilizing a surface of an object, and particularly to a sterilizing method and a sterilizing system suitable for sterilizing a surface of a mail.

[0002]

2. Description of the Related Art Recently, it has been studied to sterilize the surfaces of postal items and the like, which are handled in large quantities at one time, in order to protect them from bacterial crime.

In general, energy rays are used for sterilization, and among them, ultraviolet rays are often used. Therefore, it is conceivable to use ultraviolet rays for sterilization of the above-mentioned mail items. However, in the case of conventional UV irradiation, a large part of electric energy is not UV, but heat, etc., and not only is energy efficiency poor, but also irradiated mail items are affected by heat. It will deteriorate.

On the other hand, an electron beam can be considered as an energy beam for such sterilization. In the case of an electron beam, unlike ultraviolet rays, less energy is lost as heat or the like. However, the conventional electron beam irradiation apparatus has a high accelerating voltage for extracting an electron beam and irradiates a high-energy electron beam. However, the energy efficiency is still poor. Further, if the postal matter or the like is irradiated with a high-energy electron beam, the postal matter or the like may be deteriorated. Further, the conventional electron beam irradiation apparatus has a problem that the apparatus is large and the initial investment is high, and a shielding apparatus is inevitably large because the shielding of the secondary X-ray is necessary.

In addition, when sterilization is carried out by using electron beam irradiation, it is the current situation that no knowledge has been obtained as to what irradiation conditions are effective for sterilization. For example, Japanese Unexamined Patent Publication No. 7-20294 describes that surface sterilization is performed using an electron beam irradiation device, but it does not describe how much irradiation conditions are effective.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and effectively sterilizes an object without degrading the object with an electron beam and without using large-scale equipment. An object is to provide a sterilization method and a sterilization system that can be treated.

[0007]

In order to solve the above problems, the first aspect of the present invention is a sterilization method for sterilizing the surface of an object by irradiating the object with an electron beam by an electron beam irradiation device. , The acceleration voltage of the electron beam is less than 150 kV, and the absorbed dose of the electron beam measured using a dosimetry film is 5 to 20.
Provided is a sterilization method characterized by being 0 kGy.

A second aspect of the present invention is a sterilization method in which a plurality of objects are continuously conveyed, and the conveyed objects are irradiated with an electron beam by an electron beam irradiation device to sterilize the surface of the object. , The acceleration voltage of the electron beam is less than 150 kV, and the absorbed dose of the electron beam measured using a dosimetry film is 5 to 20.
The value of Z is in the range of 50 to 20000 kGy · m / min, where 0 kGy, the transportation speed is 300 m / min or less, and Z is the product of the absorbed dose of the electron beam and the transportation speed. A method of sterilization treatment is provided.

A third aspect of the present invention is a sterilization system for sterilizing the surface of an object by irradiating the object with an electron beam by an electron beam irradiating device, wherein an accelerating voltage of the electron beam is less than 150 kV and a dose measuring film is used. Provided is a sterilization treatment system characterized in that an absorbed dose of an electron beam measured by using it is 5 to 200 kGy.

A fourth aspect of the present invention comprises a carrier line for continuously carrying a plurality of objects, and an electron beam irradiation device for irradiating an object being carried on the carrier line with an electron beam. A sterilization system for sterilizing the surface of an object by means of which the accelerating voltage of the electron beam of the electron beam irradiation device is less than 150 kV and absorption of the electron beam measured from the electron beam irradiation device using a dosimetry film. Dose is 5
When the electron beam is irradiated to 200 kGy, the transport speed of the transport line is 300 m / min or less, and Z is the product of the absorbed dose of the electron beam and the transport speed, Z
The sterilization treatment system is characterized in that the value of is in the range of 50 to 20000 kGy · m / min.

According to the present invention, since the surface of an object is sterilized by irradiating it with an electron beam having high energy efficiency, a high-speed sterilization process is possible, and the object is not heated as in the case of ultraviolet irradiation. Therefore, deterioration of the object due to heat does not occur.

However, in the conventional electron beam irradiation apparatus, the acceleration voltage at the time of extracting the electron beam is high, and there is a possibility that it may reach a relatively deep position inside the object and deteriorate the object, and the equipment is also large. However, there are restrictions such as installation space. Moreover, the irradiation conditions suitable for sterilization have not always been clarified.

Therefore, in the first and third aspects of the present invention, the accelerating voltage for taking out the electron beam is set as low as less than 150 kV, and the absorbed dose of the electron beam measured using the dosimetry film is set in the range of 5 to 200 kGy. By prescribing, the electron beam can act mainly on the surface, so that there is little risk of deterioration of the object, large equipment is not required, and the object can be effectively sterilized.

In addition, in the second and fourth aspects of the present invention, when a plurality of objects are sterilized by continuously irradiating them with an electron beam, the transfer speed of the transfer line is changed in addition to the above conditions. 300 m / min or less, and the value Z of the product of absorbed dose of electron beam and transport speed is 50 to 20000 kGy · m / m
Since it is defined within the range of in, the conveyed object can be sterilized efficiently and effectively.

In the second and fourth aspects of the present invention, the value of Z is preferably in the range of 100 to 10,000 kGy · m / min, and the conveying speed is 10 to 300 m / min.
min, more preferably 50 to 200 m / min.

In any of the above inventions, the acceleration voltage of the electron beam is preferably 20 kV or more, and 30 to 1
30 kV is more preferable. Also, the acceleration voltage is 100 kV
The following is particularly preferable. Further, the electron beam irradiation device is preferably a vacuum tube type device which does not require a vacuum device at the time of irradiation in order to keep the electron beam generation part in a vacuum state. Furthermore, it is preferable that the distance between the electron beam emitting unit of the electron beam irradiation apparatus and the object is 10 mm or less.

In the present invention, the sterilization treatment is a concept including sterilization treatment.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below. FIG. 1 is a schematic plane view showing a sterilization processing system according to an embodiment of the present invention. This sterilization system is for sterilizing a flat object while it is being conveyed, and is applicable to, for example, an address reading device for flat mail such as letters and postcards.

In the sterilization treatment system of FIG. 1, a plurality of flat objects A are continuously conveyed in a vertical state on the conveyance line 1, and a predetermined area of the conveyance line 1 is a sterilization treatment area 1
It is a. An electron beam irradiation device 2 is fixedly arranged in a portion of the transfer line 1 corresponding to the sterilization treatment area 1a. The term "continuously transported" as used herein only needs to be a substantially continuous state and includes intermittent transportation.

The electron beam irradiation device 2 has a plurality of irradiation tubes 3 arranged on both sides of a portion corresponding to the sterilization processing area 1a of the transfer line 1, and a support member 4 for supporting these irradiation tubes 3. In the sterilization processing area 1a, both sides of the flat object A are irradiated with electron beams, and the object A is sterilized. The electron beam may be applied to only one surface of the object A.

In the electron beam irradiation device 2, the irradiation tube 3 as the electron beam generation unit is constructed as shown in FIG. That is, as shown in FIG. 2A, a vacuum tube (tube) 6 made of glass or ceramic and having a cylindrical shape.
And an electron beam generator 7 provided in the vacuum tube 6 for taking out the electron emitted from the cathode as an electron beam and accelerating the electron beam, and provided at the end of the vacuum tube 6 to emit an electron beam. It has an electron beam emitting unit 8 and a pin unit 9 for supplying power from a power supply unit (not shown). The electron beam emitting unit 8 is provided with a thin film irradiation window 10. The irradiation window 10 of the electron beam emission unit 8 has a function of transmitting an electron beam without transmitting a gas, and has a slit shape as shown in FIG. 2B. Then, the irradiation target placed in the irradiation chamber is irradiated with the electron beam emitted from the irradiation window 10.

That is, the electron beam irradiation apparatus 2 is of a vacuum tube type, which is fundamentally different from the conventional drum type electron beam irradiation apparatus. The conventional drum-type electron beam irradiation apparatus is a type that irradiates an electron beam while constantly drawing a vacuum in the drum.

An apparatus having an irradiation tube having such a structure is
It is disclosed in US Pat. No. 5,414,267, Am
It is being considered as a Min-EB device by erican International Technologies (AIT). In this device, the electron beam can be effectively extracted even at a low acceleration voltage. As a result, the electron beam can be made to act on the irradiation target at a low depth, and the adverse effect on the irradiation target is small. Further, since the energy of the electron beam is small, the amount of radiation such as X-rays generated is small, and the shield device for shielding the radiation can be miniaturized or reduced.

As described above, the shield can be downsized and reduced, and since the electron beam generation portion can be downsized due to the low acceleration voltage, the electron beam irradiation apparatus can be drastically downsized. It will be possible.

In such a sterilization processing system, the acceleration voltage for extracting the electron beam in the electron beam irradiation device 2 is 1
It is less than 50 kV. If the accelerating voltage is 150 kV or higher, the energy of the electron beam becomes too high, and the electron beam object A
The electron beam does not act effectively on the surface due to the increase in the reaching depth to the object, which not only lowers energy efficiency but also damages the object A. From the viewpoint of further increasing the energy efficiency and further reducing the damage given to the object A, 130 kV or less is preferable, and 100 kV or less is more preferable. FIG. 3 is a diagram showing the relationship between the electron beam arrival depth and the absorbed dose (arbitrary scale) at an acceleration voltage of 50 to 80 kV. From this figure, it can be seen that the electron beam can more effectively act at a position closer to the surface as the acceleration voltage becomes lower. However, if the accelerating voltage is less than 20 kV, it is difficult to take out the energy required for the sterilization process.
It is preferably at least kV, more preferably at least 30 kV. Specifically, 20 to 150 kV is preferable, and 30 to
150 kV, 20-130 kV, and further 30-130
kV, 20 to 100 kV, and 30 to 100 kV are preferable.

In order to obtain a sufficient sterilizing ability, the absorbed dose of electron beam measured with a dosimetry film is 5 to 20.
The electron beam is irradiated so as to be 0 kGy (kilo gray). If it is less than 5 kGy, sufficient sterilizing ability cannot be obtained, and if it exceeds 200 kGy, the object A is likely to be damaged. Preferably 10-100k
Gy, more preferably 10 to 50 kGy. In addition,
The absorbed dose can be measured using a dose measuring film (FAR WEST film) having a thickness of 44 μm manufactured by FAR WEST TECHNOLOGY.

The distance d between the irradiation window 10 which is the electron beam emitting portion of the irradiation tube 3 shown in FIG. 4 and the object A is preferably 10 mm or less. If the distance d exceeds 10 mm, the electron beam is attenuated due to scattering of the electron beam and the like, and it becomes difficult to effectively act on the object A.

In such an electron beam irradiating device 2, when the height (width-direction length) of the object A is longer than the length of the irradiation window 10 of the irradiation tube 3, (a), (a) of FIG. As shown in b), the plurality of irradiation tubes 3 are arranged in the height direction (width direction) of the object A.
It is preferable to arrange them in two rows and in a staggered pattern.
This is because if they are arranged in a line, there will be a gap. The two rows of irradiation tubes 3 are arranged so as to be inclined so that the electron beam is irradiated on the same line (irradiation line) on the object A. However, it is not always necessary to irradiate on the same line.

The carrying speed of the carrying line 1 is appropriately determined according to the type of the object A to be carried, but the carrying speed is 300 m / min or less. 300 m / min
When it exceeds the value, it becomes difficult to irradiate the object A with an electron beam sufficient for sterilization. It is preferably 10 to 300 m / min, more preferably 50 to 200 m / min. If the transport speed is less than 10 m / min, the transport efficiency is low. Flat mail such as letters and postcards is usually transported by 180 m / mi
It is about n.

In order to effectively sterilize the object A by irradiating the object A, which is being conveyed, with an electron beam, the value Z of the product of the absorbed dose of the electron beam and the conveying speed is 50 to 2000.
The range is 0 kGy · m / min. The value of Z is 50 kG
If it is less than y · m / min, the absorbed dose or the conveying speed is too low, and efficient sterilization cannot be performed. Further, when the value of Z exceeds 20000 kGy · m / min, the absorbed dose is too large or the conveying speed is too large, which may cause a problem of damage of the object A or achieve sufficient sterilization treatment. Can not. The preferable range of the value of Z is 100 to 10,000 kGy · m / min.

In the sterilization system configured as described above, since the surface of the object A is sterilized by irradiating the electron beam having high energy efficiency, high-speed sterilization is possible, and in the case of ultraviolet irradiation. Since the object is not heated as described above, the object is not deteriorated by the heat. Further, the acceleration voltage when extracting the electron beam of the electron beam irradiation device 2 is 150 kV.
By setting the absorbed dose of the electron beam measured with the dosimetry film to be in the range of 5 to 200 kGy, the electron beam can act mainly on the surface, and the possibility of deterioration of the object is small. Moreover, the object A can be effectively sterilized without using large-scale equipment. Furthermore, a plurality of continuously conveyed objects A
At the time of sterilizing by irradiating with electron beam, the conveying speed of the conveying line 1 is 300 m / min or less, and the product value Z of the absorption amount of the electron beam and the conveying speed is 50 to 20000 kGy · m /
Since it is defined in the range of min, the object being conveyed can be efficiently and effectively sterilized.

In the above embodiment, the number of irradiation tubes 3 of the electron beam irradiation device 2 is determined by the irradiation time and the irradiation speed. In addition, the sterilization treatment area 1 depends on the maximum treatment amount
a, that is, the length of the electron beam irradiation region is determined.

Next, the experimental results of actual sterilization treatment using the sterilization treatment system of the present invention will be described.

Bacillus pumilus was used as an indicator bacterium,
Strains were applied to nutrient agar plate medium at 30 ℃
Were cultured for 3 days and at room temperature for 5 days. After confirming the formation of spores and confirming the concentration of the bacterial solution of about 10 ⁷ cells / ml, 0.1 ml of the bacterial solution was applied on a slide glass to spread thinly and dried at 30 ° C. for 30 minutes.

A slide glass in which this bacterial solution is spread thinly is placed on a carrying line and carried, and the slide glass carried by an electron beam irradiating device installed at a predetermined position of the carrying line is irradiated with an electron beam for sterilization. Processed. At this time, the acceleration voltage of the electron beam irradiation device is set to 50 kV and 60 kV.
There are 3 levels of V and 70kV, and current at 50kV:
Dynamic Dose was set to about 118.
At 3 kGy · m / min, current at 60 kV:
A dynamic Dose of about 151.
2 kGy · m / min, and at 70 kV, the current was 0.9 mA and the dynamic Dose was about 170.
It was set to 7 kGy · m / min. The transport speed is 3.7.
It was changed between ˜17.1 m / min. The absorbed dose (Dose amount) is the thickness of FAR WEST TECHNOLOGY 4
The measurement was performed using a 4 μm dosimetry film (FAR WEST film).

The conditions at this time are shown in Table 1, and the sterilization treatment results are also shown in Table 1 and further shown in FIG. N in Table 1
o. No. 1 was air-passed without electron beam irradiation at a speed of 12.2 m / min. No. 11 did not carry or electron beam irradiation. 2 to 10 were those irradiated with an electron beam while being transported under the above conditions, and the absorbed dose (Dose amount) was 10 to 47 kGy.

[0037]

[Table 1]

As shown in Table 1 and FIG.
It was confirmed that at 0 kV, 60 kV, and 70 kV, viable bacteria were reduced by electron beam irradiation of 10 kGy or more, and there was a bactericidal effect. In particular, at an acceleration voltage of 50 kV, 40 kGy, 6
At 0 kV and 70 kV, the lowest value was 10 kGy, and it was possible to achieve the practical bactericidal ability D5 in which the viable bacteria were 1/10 ⁵ or less compared to before treatment.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above embodiment, the flat object is conveyed in an upright state, and the electron beam is irradiated in the horizontal direction.However, the flat object is conveyed in a horizontal state and the electron beam is emitted. Irradiation may be performed in the vertical direction. Further, in the above-described embodiment, a flat postal matter such as a letter or postcard is assumed, but not limited to the postal matter, it may be a food, a packaging container, or another flat article such as a (retort) pouch, Further, the present invention can be applied not only to a flat object but also to a sterilization process on a three-dimensional object. However, a flat object is preferable because it is easy to irradiate the entire surface with an electron beam.

In the above embodiment, the case where the object being conveyed is irradiated with an electron beam to sterilize its surface has been described, but a stationary object is irradiated with an electron beam to sterilize the object. This may be the case.

Further, the transfer line is not limited to the above-mentioned simple straight line, but may have a branched line,
It is possible to employ various forms such as one having a part for stocking an object and capable of irradiating an electron beam in a batch system.

The electron beam irradiation device is not limited to the above-mentioned vacuum tube type, but an ordinary drum type can be used. However, a vacuum tube type is preferable from the viewpoint of controllability. That is, the vacuum tube type electron beam irradiation apparatus typified by Min-EB can reduce the size of the shield and the inerting as described above, and the electron beam can be taken out at a low acceleration voltage. Since it is possible to reduce the size of the line generation portion, it is possible to dramatically reduce the size of the electron beam irradiation apparatus, which is extremely preferable.

Further, in the above-described embodiment, the case where only the sterilization treatment is performed is shown. However, when the paint, printing ink, etc. are cured together with the sterilization treatment, or when these are cross-linked or sterilized, the surface modification is performed. The present invention is applicable even when used in combination with other treatments such as quality improvement. Further, ultraviolet irradiation or heat treatment may be supplementarily used.

[0044]

As described above, according to the present invention,
Since the surface of the object is sterilized by irradiating it with an electron beam with high energy efficiency, high-speed sterilization is possible, and because the object is not heated as in the case of UV irradiation, the object does not deteriorate due to heat. . In the conventional electron beam irradiation device, the acceleration voltage when extracting the electron beam is high, it may reach a relatively deep position inside the object and deteriorate the object, and the equipment is also large and installed. Although there were restrictions such as space, and the irradiation conditions suitable for sterilization were unknown, in the present invention, the acceleration voltage at the time of extracting the electron beam was reduced to less than 150 kV, and the electron measurement was performed using a dosimetry film. By prescribing the absorbed dose of rays in the range of 5 to 200 kGy, the electron beam can act mainly on the surface, so there is little risk of deterioration of the object, and no large-scale equipment is required. It can be sterilized. In addition, when sterilizing a plurality of objects that are continuously transported by irradiating them with an electron beam, in addition to the above conditions, the transport speed of the transport line is 300 m / min or less,
And the value Z of the product of absorbed dose of electron beam and transport velocity is 50
Since it is defined in the range of up to 20000 kGy · m / min, the conveyed object can be efficiently and effectively sterilized.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a sterilization processing system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a structure of an irradiation tube of an electron beam irradiation device used in the sterilization processing system of FIG.

FIG. 3 is a diagram showing a relationship between an electron beam arrival depth and an irradiation dose at an acceleration voltage of 50 to 80 kV.

FIG. 4 is a diagram for explaining a distance between an irradiation window, which is an electron beam emission unit, and an object.

5 is a diagram showing an example of an arrangement of irradiation tubes of an electron beam irradiation device used in the sterilization processing system of FIG.

FIG. 6 shows electron beam acceleration voltages of 50 kV, 60 kV, and 70.
The figure which shows the relationship between the dose amount of electron beam irradiation in the case of kV, and the viable cell amount.

[Explanation of symbols]

1 ... Transfer line 1a ... Sterilization area 2 ... Electron beam irradiation device 3 ... Irradiation tube 4 ... Support member 6 ... Vacuum tube 7 ... Electron beam generator 8 ... Electron beam injection unit 9: Pin part 10 ... Irradiation window A ... object

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akihiko Kizaki             2-3-13, Kyobashi, Chuo-ku, Tokyo Toyo             Nki Manufacturing Co., Ltd. (72) Inventor Ken Hirose             2-3-13, Kyobashi, Chuo-ku, Tokyo Toyo             Nki Manufacturing Co., Ltd. F term (reference) 4C058 AA02 AA25 AA26 BB06 CC02                       CC04 DD03 DD07 EE23 KK03                       KK22 KK32 KK44

Claims (20)

[Claims] 1. A sterilization method in which an object is irradiated with an electron beam by an electron beam irradiation device to sterilize the surface of the object, wherein an accelerating voltage of the electron beam is less than 150 kV and an electron measured using a dosimetry film. Line absorbed dose is 5 to 200 kGy
A sterilization method comprising: 2. A sterilization method in which a plurality of objects are continuously transported, and the transported objects are irradiated with an electron beam by an electron beam irradiating device to sterilize the surface of the object. Voltage is less than 150 kV, absorbed dose of electron beam measured with dosimetry film is 5-200 kG
y, when the transport speed is 300 m / min or less, and Z is the product of the absorbed dose of the electron beam and the transport speed, Z
Value is in the range of 50 to 20000 kGy · m / min. 3. The value of Z is 100 to 10,000 kGy.
The range of m / min is the sterilization method according to claim 2. 4. The conveying speed is 10 to 300 m / min.
The sterilization method according to claim 2 or 3, wherein 5. The transport speed is 50 to 200 m / min.
The sterilization method according to claim 4, wherein 6. The sterilization method according to claim 1, wherein the acceleration voltage of the electron beam is 20 kV or more. 7. The sterilization method according to claim 6, wherein the acceleration voltage of the electron beam is 30 to 130 kV. 8. The accelerating voltage of the electron beam is 100 kV or less, according to any one of claims 1 to 7.
The sterilization method according to item. 9. The sterilization method according to claim 1, wherein the electron beam irradiation device is a vacuum tube type. 10. The sterilization method according to claim 1, wherein the distance between the electron beam emitting unit of the electron beam irradiation apparatus and the object is 10 mm or less. . 11. A sterilization system for sterilizing the surface of an object by irradiating the object with an electron beam by an electron beam irradiating device, wherein an accelerating voltage of the electron beam is less than 150 kV, and an electron measured using a dosimetry film. Line absorbed dose is 5 to 200 kGy
A sterilization treatment system characterized in that 12. A transport line for continuously transporting a plurality of objects, and an electron beam irradiation device for irradiating an object being transported on the transport line with an electron beam, the surface of the object being irradiated with the electron beam. A sterilization system for sterilization, wherein the electron beam accelerating voltage of the electron beam irradiation device is less than 150 kV, and the absorbed dose of the electron beam measured from the electron beam irradiation device using a dose measurement film is 5 to 200 kGy. When the value of the product of the absorbed dose of the electron beam and the transfer speed is Z, the value of Z is 50 to 2 when the transfer speed of the transfer line is 300 m / min or less.
A sterilization system characterized by being in the range of 0000 kGy · m / min. 13. The value of Z is 100 to 10,000 kG.
2. The range of y · m / min.
The sterilization treatment system according to 2. 14. The transportation speed of the transportation line is 10 to 3
It is 00 m / min, The sterilization processing system of Claim 12 or Claim 13 characterized by the above-mentioned. 15. The transfer speed of the transfer line is 50 to 2
The sterilization treatment system according to claim 14, wherein the sterilization treatment system is 00 m / min. 16. The sterilization system according to claim 11, wherein an acceleration voltage of an electron beam of the electron beam irradiation device is 20 kV or more. 17. The electron beam accelerating voltage of the electron beam irradiation apparatus is 30 to 130 kV.
The sterilization treatment system according to item 6. 18. The electron beam accelerating voltage of the electron beam irradiation apparatus is 100 kV or less.
18. The sterilization system according to any one of claims 17 to 18. 19. The sterilization processing system according to claim 11, wherein the electron beam irradiation device is a vacuum tube type. 20. The sterilization system according to claim 11, wherein the distance between the electron beam emitting unit of the electron beam irradiation apparatus and the object is 10 mm or less. .