PatentDe  


Dokumentenidentifikation EP0992040 25.03.2004
EP-Veröffentlichungsnummer 0000992040
Titel BESTRAHLUNGSANORDNUNG, VERFAHREN ZUR BESTRAHLUNG VON PRODUKTEN, ANLAGE ZUR ERZEUGUNG STERILER PRODUKTE, DIE EINE SOLCHE ANORDNUNG UMFASST UND BENÜTZUNG EINER SOLCHEN BESTRAHLUNGSANORDNUNG ZUR ERZEUGUNG STERILER PRODUKTE
Anmelder Scanditronix Medical AB, Uppsala, SE
Erfinder LINDHOLM, Mikael, S-745 91 Enköping, SE;
ANDERBERG, Bengt, S-756 45 Uppsala, SE
Vertreter derzeit kein Vertreter bestellt
DE-Aktenzeichen 69727703
Vertragsstaaten DE, FR, GB, IT
Sprache des Dokument EN
EP-Anmeldetag 30.06.1997
EP-Aktenzeichen 979359213
WO-Anmeldetag 30.06.1997
PCT-Aktenzeichen PCT/SE97/01179
WO-Veröffentlichungsnummer 9900801
WO-Veröffentlichungsdatum 07.01.1999
EP-Offenlegungsdatum 12.04.2000
EP date of grant 18.02.2004
Veröffentlichungstag im Patentblatt 25.03.2004
IPC-Hauptklasse G21K 5/04
IPC-Nebenklasse H01J 37/30   

Beschreibung[en]

The present invention generally relates to an arrangement for irradiation of products with charged particles.

By existing technology, there are presently three main approaches of sterilising. The first approach is by heating in an autoclave. This method can only be used for heat resistive materials. Since many products are not heat resistive, they are not treatable in an autoclave.

Another approach is to expose the product to poisonous gas. This poisonous gas is normally ethylene oxide, which is poisonous, carcinogenic and explosive. The use of this gas is surrounded by extensive security regulations. Among other things, the products have to be ventilated during a very long time period in order to decrease the rest level of gas in the material to approved levels. The products are packed in a semi-permeable package and ventilating of gas takes place through this layer. Bacterial cultivation is requested before the products are allowed to be delivered. Together, all this results in that a normal treatment time becomes 7-10 days, transports excluded. Rest levels of gas in the material are considered as very dangerous and the tendency is that the allowed limits are continuously lowered.

The third approach is to use ionising radiation. A great advantage with such methods is that they are considered as very safe, and for confirmed absorbed radiation doses above 25 kGy, no bacterial cultivation has to be performed before delivery. Furthermore, the products may be packed before the sterilisation, since the radiation penetrates the package materials. One type of ionising radiation used is gamma radiation from cobalt sources. These radiation sources are generally very strong, in the order of magnitude of 1 MCi, which requires strong radiation shields, e.g. concrete walls with a thickness of 2 m. The penetration ability is very good, but the exposure time is very long, sometimes up to several days.

Another type of ionising radiation is charged particles from accelerators, preferably electrons. They have a more limited penetration depth, but is generally much easier to handle. Known technology uses 10 MeV electrons to achieve a penetration depth in the materials which is large enough. This calls for large accelerators and even in such cases, the radiation shield may consist of up to 2 m of concrete. In order to be able to use such methods, practically and economically, large separate central plants are demanded. Contract sterilising is the normal proceeding for plants of ionising radiation, which means that the sterilising is performed separate from the production, which in turn gives rise to long storage times and transport costs. The investments for such plants are in the order of magnitude of 30-60 million Swedish kronor.

An alternative manner is to irradiate the products with charged particles of a lower energy, preferably electrons, which gives a lower penetration depth. In order to be able to use this method in practice, by use of known technology, which only irradiates the products from one side, the products have to be turned and run another time through the sterilising device to achieve a sufficient penetration depth. This normally gives rise to internal logistic problems and risks for mishandling, unless double arrangements are used after each other.

One way to irradiate an object from different directions is known from INP Novosibirsk (c.f. the US patent 4 121 086). In this concept, the electron beam from an accelerator is deflected into two alternative beam paths besides the undeflected beam path, which three beam paths in the end impinges on the radiation target in one and the same spot, but from three different directions. The deflection is performed by a deflection magnet and redeflection of the deflected beams is performed by two redeflection magnets. However, this radiation source only operates with three discrete beam paths with individually scanned beam. Such a radiation device is mainly suited for radiation of products with circular cross section, or fluids transported through the irradiation area in circular pipes.

In the US patent 4 201 920, an irradiation arrangement for irradiation of products from two sides with a scanning electron beam is disclosed. The radiation target is asymmetrically arranged in the area scanned by the electron beam and electrons not impinging directly on the radiation target are deflected to impinge on the back side of the radiation target. The pole pieces of the electromagnet are adapted dependent on the shape and size of the radiation target, to give a homogeneous irradiation. However, this equipment has a number of severe disadvantages.

A first disadvantage is that one has to modify the geometrical shape of the pole pieces for irradiation of products with different shape or size in order to, according to the description, achieve an optimally efficient irradiation. This implies a costly and time consuming pole change when changing the products to be irradiated. If instead the same pole pieces are kept, the patent does not disclose anything about how a control of the scanning could make the use of the beam time more efficient.

Furthermore, the electrons which are redeflected are moving along a longer geometrical path, which means other focusing properties for the redeflected electron beam as compared with the directly impinging electron beam, when they impinge on the products to be irradiated. How such irradiation inhomo-genities are to be compensated for is not discussed in the document.

A third disadvantage with the device in the US patent 4 201 920 arises at irradiation of products which do not continuously occupies the full available radiation sector, e.g. for irradiation of products of an uneven shape or when the products are separated by an interspace. This is the normal case during production of medical disposable products. In these cases, at least a part of the beams will pass the radiation area without being absorbed. These will instead be incident back towards the products and may cause incorrect and inhomogeneous dose distribution. Furthermore, this effect is not equal for the two different sides of the product.

To use an irradiation arrangement efficiently, the products to be irradiated are normally transported in and out from the radiation sector during operation. This is performed by means of any conveying system or assembly line system through the irradiation arrangement. A usual problem is that products are stuck or moving on the conveyor belt. This is particularly true for small, irregular and flabby packages. The most common way of conveying is to let the products lie on a conveyor belt, which passes them into the irradiation arrangement, through the radiation sector and out from the arrangement. The path of the conveyor belt has to be bent in order to be able to efficiently protect for secondary X-ray radiation, i.e. pass through a so-called labyrinth. The risk for that the products are moving at the conveyor belt or are stuck within the irradiation arrangement is large by such technical solutions. The result is varying uncontrolled radiation doses and risk for fire, respectively, since a power of above 6 kW is used. If an internal radiation dose measurement is used, all electronics is rapidly destroyed by the ionising radiation and has to be replaced periodically. If the products, considering the economical efficiency, are packed close together, the risk for overlapping, shadowing and halts increases with an unacceptable quality as the result.

In order to overcome the above described disadvantages and to provide an irradiation arrangement which is simple and small enough for being installed directly in a production line, the present invention presents a solution. The invention provides a device for double-sided irradiation of the products by electrons with a relatively low energy (1-10MeV), and preferably between 1,5 and 2,5 MeV, which penetrates goods with a thickness less than 1 g/cm2. The device comprises controllable means, which causes the particle beam to scan over the surface of the product from two sides with controllable focusing properties. The scanned particle beams are preferably incident towards the product in an angle close to 90 degrees and particles, not absorbed by the product or in the vacuum windows surrounding the products, impinge on a particle stopper, supplied for this purpose. The controllable means preferably comprises a focusing lens, a controllable scanning magnet for deflection of the particle beam and two redeflection magnets for bringing the particle beams back to the radiation area for the products. The scanning magnet and the focusing lens are controlled in such a manner that a homogeneous irradiation is achieved over the entire radiation sector from two opposite directions.

A conveyor device has been constructed, which allows the double-sided irradiation at the same time as it flexibly fixes the products during the transport through the irradiation arrangement, whereby the radiation dose to which the products are exposed may be totally controlled by the feeding velocity of the conveyor device.

Owing to that a lower particle energy and a double-sided irradiation is used, the size of the arrangement, including the radiation shield may be made relatively small. Together with the design of the conveyor device, this results in that the arrangement may fit together with a normal production line.

Other advantages and features are described referring to an exemplifying embodiment in the following detailed description and in connection with the associated drawings.

Fig. 1
is a vertical cross section through a sterilising device according to the present invention;
Fig. 2
is an enlargement of a part of the irradiation equipment of the sterilising device shown in fig. 1; and
Fig. 3
is a vertical section of a sterilising device according to the present invention, taken perpendicular to the one shown in figs. 1 and 2, and which substantially shows the function of the conveyor belt.
Fig. 4
is a diagram showing a typical behaviour of the variation of current in the scanning magnet during a scanning cycle.

Fig. 1 shows an embodiment of a sterilising device comprising an irradiation arrangement according to the present invention. The irradiation arrangement comprises a particle accelerator. The particle accelerator comprises a particle source 1, a buncher 2 and linear accelerator 3. The particle source 1, in this embodiment an electron gun, which is built in a conventional manner, emits the particles to be used for the irradiation. In this embodiment, the electron gun 1 is of a Pierce type. The buncher 2 pushes the original continuous electron beam together in bunches and introduces the bunches as electron pulses into a linear accelerator 3. Thereby, fewer electrons end up outside any accelerable phase window in the linear accelerator 3, at the same time as the energy dispersion of the electron beam output from the accelerator reduces. In this embodiment, the buncher gives particle pulses of a frequency of 3 GHz. The linear accelerator accelerates the particles by means of electrical fields and sends in the particles towards a radiation chamber 4. In this embodiment, the particles are accelerated to an end energy of 1.5 to 2.5 MeV, and with a particle pulse current in the order of magnitude of 800 mA, which gives an average particle current of 2.4 mA. The pulse lengths are about 5 µs and the pulse repetition frequency is 600 Hz. The particle beam is focussed by a quadrupole magnet 6 at the exit of the linear accelerator, before it enters into a scanning magnet 7. The total arrangement comprising particle accelerator and radiation chamber is enclosed by radiation shields 5, consisting of lead, with an approximate thickness of 250 mm.

In fig. 2, an enlarged drawing of the radiation chamber is shown. When the particle beam leaves the accelerator, it is bent by the scanning magnet 7 in an angle β with respect to the original radiation axis. The angle β may in this embodiment vary between about 15 and 45 degrees, in both positive and negative directions. The scanning magnet is an electromagnet operated by a bipolar current supply, the output current of which may be programmed. The particle beam is incident in a direction of redeflection magnets 8, 9, positioned at each side. The redeflection magnet 8, 9 is in this embodiment a permanent magnet with a particular shape, which is described more in detail here below. When the particle beam enters between the pole pieces 9 of the redeflection magnets, it is bent into a path determined by the magnet flux in the pole gap which is adapted for a deflection angle of β+90°, which implies that the particle beam leaves the field of the redeflection magnet in a path perpendicular to the original radiation axis. The particle beam passes a vacuum window 11, which normally consists of a thin metal foil of titanium or aluminium. In the central area of the radiation chamber 4, hereinafter referred to as the radiation sector 13, the products to be irradiated pass on a conveyor belt 14 (see fig. 3): The radiation beam will therefore impinge on the products with a radiation angle of essentially 90 degrees with respect of the original radiation axis. Beam optics calculations have been performed to determine the size of the radiation spot. In this embodiment, the radiation spot at the position of the irradiated products is approximately 20 mm. The part of the radiation passing the radiation sector 13 and the two vacuum windows 11 without being absorbed, e.g. as a result of that there are no products in the radiation sector at the moment, continues a rectilinear path until it enters between the pole pieces 9 of the opposite redeflection magnet, is bent and absorbed by a cooled particle stopper 10, preferably made by copper or aluminium.

In fig. 2, six of the innumerable possible particle paths a-f in the radiation chamber are shown. Each particle path is characterised by its exit angle β from the scanning magnet 7. By changing the output current from the current supply of the scanning magnet, the exit angle β may be changed. This exit angle uniquely determines the position where the particle beam enters into the magnet field of the redeflection magnets and is started to be bent. The bending of the particle beam is performed along a circular arch, the

radius of which is determined by the mass and velocity of the particle and the strength of the magnetic field. This embodiment is based on a perpendicular irradiation of the products, which gives rise to a demand that the particle beam should leave the influence of the redeflection magnet under a right angle with respect of the original beam axis. If one starts from the position, where the particle beam enters into the magnet field of the redeflection magnet, and the bending radius is known, a position, where the beam has a perpendicular direction, is uniquely defined. This position has to coincide with the position where the particle beam leaves the magnet field, whereby the local appearance of the redeflection magnet uniquely is determined. Since the particle beams enter into the field of the redeflection magnet in different angles at different positions, the design of each small part of the redeflection magnet is determined by the demand of the perpendicular irradiation angle. A shape of the redeflection magnet 9 may thereby, mainly by pure geometrical considerations, easily be calculated. The same considerations are of course valid for the opposite redeflection magnet, when the angle β is negative.

In the shown embodiment, the geometry of the redeflection magnet has been approximated to a circular arch. The centre of the circle is placed 0.77 cm from the entrance to the scanning magnet as measured along the entering beam and 97.2 cm from the axis of the entering beam. The circle has a radius of 139.8 cm. The angle of irradiation will in this case deviate from 90 degrees by less than 1 degree for all scanning positions.

By changing the output current from the current supply of the scanning magnet, the particle beam may thus irradiate the products 13 perpendicularly at different positions, and by changing the polarity of the current, the products may also be irradiated from the other side. If the current through the scanning magnet has a high positive value, the particle beam is bent by a large angle and follows e.g. the particle path a and impinges on the irradiated product close to its inner, towards the accelerator facing end. When the current then gradually is reduced, the exit angle from the scanning magnet will decrease, which in turn leads to that the particle beam hits the irradiated product increasingly further out, away from the accelerator. The particle beam c, with a rather small exit angle, impinges on the product at its farther end, and its exit angle is so small that it starts to become disturbed by the mechanical parts of the vacuum enclosure. A particle beam with an exit angle with lower absolute value, is thus not to any real use and forms only radiation losses, why the current supply of the scanning magnet rapidly changes its polarity to give rise to a particle beam d, with corresponding negative exit angle instead. This particle beam irradiates the outer part of the product, but now from the other side. By now gradually, in absolute figures, increase the current through the scanning magnet, a particle beam with a gradually larger negative exit angle is achieved, whereby the beam irradiates the product closer to the accelerator end. In order to return to the original state, it is advantageously to scan back in a similar manner, since one otherwise easily would get problems with rapid current changes in the scanning magnet. The particle beam during a complete scan, thus starts e.g. from the path a, scans over to the path c, then rapidly changes to the path d and scans over to the path f, after which it turns and scans back to the path d, rapidly changes over to path c and scans back to the original path a. In this embodiment, the largest exit angle is approximately 45°, while the angle of the smallest absolute value is approximately 15°.

At the occasions, when the radiation sector is not fully covered by the products to be irradiated, e.g. for irregularly formed products or for interspaces between the products when they are transported past the radiation sector, a part of particle beam will pass the radiation sector 13 and the vacuum windows 11 without being absorbed. This radiation continues in a rectilinear path towards the opposite redeflection magnet 8, 9. When the beam enters between the pole pieces 9 of the redeflection magnet, it is bent into a curved path. Due to the direction of the magnetic field, this curvature will be directed away from the accelerator. Examples of such a path is indicated by g in fig. 2. These paths will impinge on the particle stopper 10 positioned at either side, where the particles are absorbed and the heat generation thereby occurring is collected by the cooling medium of the particle stopper. In this way it is avoided that the radiation which is not absorbed by the products will destroy the irradiation arrangement from the inside or will cause incorrect dose distribution. In the present embodiment, the particle stopper is made of aluminium or copper and the cooling medium in the particle stopper is circulating water. Aluminium has the advantage to have a low cross section for X-ray emission, while copper has the advantage of conducting the heat very efficiently. Both materials may advantageously be used in vacuum applications.

Each beam leaving the particle accelerator 1-3 has a certain emittance and energy dispersion. In the shown embodiment, the emittance has been assumed to be 5 mm mrad and the energy dispersion ±3%. This means that along the path of the beam, the cross section of the beam will vary slowly. Each element along the path of the beam has its characteristic manner to influence the properties of the particle beam. This means, that if one compares the size of the radiation spot at the radiation sector, with identical settings for the quadropole lens, between two different deflections in the scanning magnet, these will differ. Such a variation may give rise to an inhomogeneous irradiation of the product. To compensate for this effect, the quadropole lens 6 may in this embodiment of the invention be used to change the focusing properties of the particle beam at different deflection angles.

It is important that the products at the conveyor belt are irradiated with an even dose over the entire irradiated area. Since the relation between the current of the scanning magnet and the radiation position on the product generally does not follow a linear relation, the scanning of the current has to be adapted in such a way that the irradiation of the product becomes even. An example of a typical current diagram for a scanning cycle is illustrated in fig. 4. The scanning starts at the time t0, where the current I0 is sent through the scanning magnet, and the current then varies along a curve, whereby the scanning magnet scans the particle beam evenly over the surface of the product up to the time t1, where the current I1 is sent through the scanning magnet. The polarity of the current is rapidly turned and the product is irradiated from the other side. The negative current is increased from I2 to I3 according to a corresponding curve until the time t2, when the cycle turns and scans back in a corresponding manner. The cycle is completed at the time t4. The scanning of the current may be performed continuously or in the form of discrete steps in pace with the pulse frequency. Independently of used method, each new particle pulse will impinge on the product at a new position. In this embodiment, this step between successive particle beam pulses is about 15 mm at the product position, which means that two successive irradiation areas do overlap somewhat to ensure that all surfaces are irradiated. The total scanning width is about 400 mm, which sets the maximum width of the products to be irradiated. A total scanning cycle as described above is repeated with a frequency of 5.6 Hz. To achieve an absolutely homogeneous radiation dose over the entire surface of the product, a fine adjustment of the current profile may be performed after measurement of the radiation dose along the plane of irradiation.

In the shown embodiment, the relation between the field strength of the scanning magnet and the scanning position is very close to linear. The deviation is calculated to be maximum 3%. This does not have such a big principal importance, but may simplify the practical use. The scanning magnet has in the shown embodiment a pole gap of 4 cm. The maximum magnetic field needed in the scanning magnet is 33 mT. By a bipolar current supply of 72 V and 6 A, 174 turns are required in the magnet coils. Change of irradiation side at the lowest used field as described above performed, is in this case from + 10 mT to -10 mT. This should be done as fast as possible, without making the inductive voltage too large, and in the shown embodiment, this is performed during the duration of two pulses.

The currents I0 and I3, respectively, thus correspond to the largest used deflection in the scanning magnet, in positive and negative direction, respectively, which in turn correspond to a radiation position in the radiation sector positioned at the end closest to the accelerator. In the same manner, the currents I1 and I2, respectively, correspond to a radiation position at the farther, away from the accelerator facing, end. If products with a size which do not occupy the entire width of the radiation sector are to be irradiated, the currents I0, I1, I2, and I3 may easily be adapted so as to not radiate the area outside the products. Such a control possibility of the radiation width, makes the use of the arrangement for different types of products very flexible.

The products are brought through the radiation sector in the radiation chamber on a conveyor belt, which is more closely described below. The feeding velocity is adapted so as to give the products the necessary radiation dose. Requested feeding velocity is given by the radiation power, the scanning width and the required dose and for this embodiment it is 0.76 m/min at 6 kW radiation power, 30 cm scanning width and 25 kGy dose.

The geometry of the irradiation arrangement is important. A system using directly impacting particles inevitable obtains different angle of incidence against the products since the beam is deflected from one and the same point. Either the distance between the scanning magnet and the product has to be large, or the angle of incidence will vary substantially for products of reasonable dimensions. For instance, an angle of incidence of 45 degrees against the product reduces the penetration depth by 30%. A system where all beams are redeflected before the irradiation may be constructed compact and give homogeneous angles of incidence. Furthermore, if the system is symmetric, the control of the scanning is facilitated even if this does not imply any fundamental difference.

In the irradiation arrangement, the products are normally irradiated when they are placed in a horizontal position. At use of direct impact, it is required that the accelerator arrangement is directed substantially vertically, which gives the arrangement a large height and may be impossible to install in premises with normal roof height. By using redeflected beams, one may easily create a configuration where both the accelerator device and the products may be placed substantially horizontally.

By using a relatively low particle energy, a particle accelerator of a relatively small size may be used, and the lower energy reduces the need for radiation shielding. The total size of the arrangement may, due to this and the geometrical arrangements described above, be reduced significantly and the described embodiment has a total volume of 8 m3 and covers an area of 4,2 m2. The total mass is approximately 16 000 kg. This, together with the fact that the transport needs and the internal logistic problems at the irradiation arrangements are set aside by the double-sided irradiation, implies that the arrangement advantageously is used directly in a production line, which sets aside many problems in connection with transport and storage.

In fig. 3, a vertical section of an embodiment according to the present invention is shown, perpendicularly to the one shown in figs. 1 and 2, and which substantially shows the operation of the conveyor belt. The products, often in the form of tubes or other small details, packed in flabby bags, are to be transported past the particle beam with an even velocity to achieve a homogeneous radiation dose. By efficiency point of view, these products should be able to be positioned closely without risk for being moved or shadowing each other during the transport through the irradiation arrangement. This transport is performed by means of a conveyor belt, which comprises two webs 14, 15 of flexible net or the like, with a width larger than the one of the products, but which may pass through the radiation chamber 4. The products to be irradiated are transported jammed in between the two net webs. Wires or chains are arranged along the edges of the net webs, which are used to drive the net webs forward and to stay the net webs. The net webs are driven separately by one motor 17 each, but in a co-ordinated manner with each other, in a closed travelling path each. These travelling paths are connected to each other during the path at which the webs are passing through the particle radiation device, from the position 19 where the products are brought to the webs to the position 20 where the products are leaving the webs. Along this length, the wires or chains are jammed together at regular intervals by rolls 16, and in this manner the net webs jam the products to be irradiated between each other.

In order for the conveyor belt to allow for irradiation from both sides and not obstruct the particles in any substantial amount, the net of the net webs 14, 15 are made of thin metal wire, with a diameter less than 1 mm, and with a distance between the wires of approximately 20 mm. The conveyor belt is in this manner very flexible and may easily be driven along a narrow and curved tunnel by the rolls 16 through a so-called labyrinth 18. The labyrinth is necessary for stopping the secondary X-ray radiation to penetrate out from the radiation chamber. Since the products are fixed by the net webs, this passage may be performed without risk for displacements of the products along the conveyor belt. It is thus guaranteed that the velocity of the products past the radiation corresponds to the velocity of the net webs, which may be measured and regulated from the outside. This velocity is regulated to give the products the right radiation dose.

The entire irradiation device is supposed to be included in a production line and the products brought in at 19 are assumed to originate directly from a production device for the products. At the output side 20, a packaging machine may e.g. be disposed to take care of the radiation treated products.

The previous detailed description of an embodiment has only been given to facilitate the understanding of the basic idea of the invention and no additional limitations beyond what is stated by the patent claims should be understood from this, since alterations are obvious for someone skilled in the art. All numerical examples given above are tied to the specific exemplified embodiment and are not generally true for the invention as such.

Someone skilled in the art easily understands that e.g. the type of particle accelerator may be varied. The exact design of the particle extraction and acceleration is not of importance for the basic features of the invention. Given numerical examples are related to the exemplified embodiment and have generally no direct influence of the basic features of the invention, but will of course effect the design of other parts of the irraditaion arrangement. The required particle energy is thus important for the design of the construction of the accelerator as well as the extent of the radiation shields. The pulse repetition frequency, the particle pulse current and the beam size effect e.g. the maximum scanning velocity.

In the same manner, it is understood that many parts of the equipment may be changed for other types with a corresponding effect. One may as one example mention that, instead of the permanent magnets used in the embodiment above, one may use electromagnets as redeflection magnets. However, these are more sensitive to radiation damages and are generally more space consuming, why permanent magnets are to prefer. However, this choice does not influence the basic feature of the invention. The scanning magnet may in a similar way also be designed in alternative ways, where the exit angle of the beam from the magnet is easily controllable.

Alternative solutions are also that the particle accelerator is designed with a controllable focusing action, or that this function is integrated with the scanning magnet. The vacuum window may in an analogue manner be designed in different ways and with different materials, but have the same basic properties, i.e. to isolate vacuum but to let the particle beam through with as small losses as possible.

The particle stopper in the described embodiment consists of a separate means disposed at the redeflection magnets. Other imaginable solutions are e.g. that they are disposed with another geometry, but still acting in the manner stated in the claims. The absorption means do not even have to consist of a separate particle stopper, but its function may e.g. be integrated in other parts of the chamber, e.g. directly in the walls of the radiation chamber.

The range of angles, within which the scanning magnet operates is of course dependent of the design of the magnet and its function, and by the geometrical configuration of the redeflection magnets and the radiation sector. Given numerical examples are related solely to the described embodiment.

It is also understood that even if the above described embodiment operates with perpendicular irradiation of the products, other geometrical configurations may be thinkable. Such changes will thereby have repercussions on the exact geometrical design of the redeflection magnets and the control of the scanning magnet. The perpendicular irradiation is, however, considered as the most favourable, since it gives the largest penetration depth for a certain particle energy for substantially planar products. For arrangements dedicated for a product with a certain geometrical shape, the optimal geometrical configuration may be different, e.g. with other irradiation directions or positioning of the radiation sector.

The details and in particular the given numerical indications of the control of the scanning magnet are also related only to the described embodiment. The same is of course valid for the design and the stated dimensions of the total size of the arrangement, which only serves to emphasize the advantage with the compact shape of the irradiation arrangement of the embodiment.

The transport system described is also solely exemplifying. The detailed design of the net webs may and should be determined by which products are to be transported. The transport webs are here described as net webs, but fully covering webs of any thin radiation durable material with low electron absorption would also be imaginable, as well as webs which only covers parts of the products.


Anspruch[de]
  1. Bestrahlungsanordnung zur Bestrahlung von Produkten mit einem Strahl beschleunigter geladener Teilchen, umfassend eine Teilchenbeschleunigungs-Vorrichtung (1-3), einer Bestrahlungskammer (4) zur Aufnahme von Teilchen zu deren Bestrahlung, umfassend einen Bestrahlungsbereich (13), in dem die Bestrahlung der besagten Produkte stattfindet, eine Trägervorrichtung (14-18) für die besagten zu bestrahlenden Produkte zur Bestrahlung der besagten Produkte von wenigstens zwei Seiten und steuerbare Mittel (6-9) zum Abtasten von dem besagten Strahls geladener Teilchen über die Oberfläche der besagten Produkte wechselweise von wenigstens zwei Seiten, wobei die besagten steuerbaren Mittel einen steuerbaren Abtastmagneten (7) zur Ablenkung des besagten Teilchenstrahls und zur Rückablenkungsmittel (8,9) umfassen, wobei die Rückablenkungsmittel an wenigstens zwei Seiten des besagten Bestrahlungsbereichs angeordnete Rückablenkungsmagneten (8) aufweisen,

    dadurch gekennzeichnet, dass

    die besagten Rückablenkungsmagneten (8,9) eine. geometrische Form aufweisen, durch die deren magnetisches Feld den besagten Teilchenstrahl (a-f), welcher von dem besagten Abtastmagneten einfällt, in einer im Wesentlichen senkrecht zu der Richtung, die die Strahlachse unmittelbar vor dem Durchtritt durch den besagten Abtastmagneten hat, auf den besagten Bestrahlungsbereich hin ablenkt, wobei im Wesentlichen alle Teilchenstrahlen sowohl durch die Ablenkung in den Abtastmitteln als auch durch die Rückablenkung in den Rückablenkungsmitteln verlaufen.
  2. Bestrahlungsanordnung gemäß Anspruch 1, gekennzeichnet durch

    zumindest ein Absorptionsmittel zur Absorption beschleunigter Teilchen und

    dadurch, dass die besagten Rückablenkungsmagneten (8,9) eine geometrische Form aufweisen, durch die deren magnetisches Feld außer, dass es den besagten Teilchenstrahl (a-f) auf den Bestrahlungsbereich (13) hin ablenkt, zur gleichen Zeit diejenige Teilchenstrahlung, die durch den besagten Bestrahlungsbereich (13) ohne absorbiert zu werden hindurchtritt, auf die besagten Absorptionsmittel hin ablenkt.
  3. Bestrahlungsanordnung gemäß Anspruch 2, dadurch gekennzeichnet, dass das/die besagte (n) Absorptionsmittel einen Teilchenstopper (10) aufweisen, welcher in dem Raum zwischen den Polstücken (9) der besagten Rückablenkungsmagneten angeordnet ist.
  4. Bestrahlungsanordnung gemäß einem der Ansprüche 1 - 3,dadurch gekennzeichnet, dass jedes Produkt während der Bestrahlung derart in dem Bestrahlungsbereich (13) platziert ist, dass die Flächennormale der zu bestrahlenden Oberfläche in eine Richtung weist, die sich wesentlich von der Ursprungsrichtung des Teilchenstrahls unterscheidet.
  5. Bestrahlungsanordnung gemäß Anspruch 4, dadurch gekennzeichnet, dass jedes Produkt während der Bestrahlung derart in dem Bestrahlungsbereich (13) platziert ist, dass die Flächennormale der zu bestrahlenden Oberfläche in eine Richtung weist, die im Wesentlichen senkrecht zur Ursprungsrichtung des Teilchenstrahls ist.
  6. Bestrahlungsanordnung gemäß einem der Ansprüche 1 - 5,dadurch gekennzeichnet, dass die besagten steuerbaren Mittel zusätzlich ein fokussierende Linse für geladene Teilchen (6), wobei die fokussierende Linse (6) synchron mit dem steuerbaren Abtastmagneten (7) steuerbar ist, um eine konstante Strahlgröße in dem Bestrahlungsbereich zu erzeugen.
  7. Bestrahlungsanordnung gemäß einem der Ansprüche 1 - 6,dadurch gekennzeichnet, dass die besagten Teilchen Elektronen sind.
  8. Bestrahlungsanordnung gemäß einem der Ansprüche 1 - 7,dadurch gekennzeichnet, dass die Energie der bei der Bestrahlung in dem Bestrahlungsbereich verwendeten Teilchen zwischen 1 und 10 MeV, vorzugsweise zwischen 1,5 und 2,5 MeV, gewählt ist.
  9. Bestrahlungsanordnung gemäß einem der Ansprüche 1 - 8,dadurch gekennzeichnet, dass die besagte Trägervorrichtung (14-18) eine Transportvorrichtung umfasst, welche die Produkte durch den Bestrahlungsbereich (13) hindurch transportiert, die Produkte während des Transports durch die besagte Bestrahlungsanordnung an der Transportvorrichtung fixiert, und welche mit Bedienungsmitteln (16,17) verbunden ist, wobei die Bedienungsgeschwindigkeit von einer Position außerhalb des Bestrahlungsraums steuerbar ist.
  10. Bestrahlungsanordnung gemäß Anspruch 9, dadurch gekennzeichnet, dass eine vorbestimmte Strahlungsdosis dadurch erreicht wird, dass die Bedienungsgeschwindigkeit der besagten Trägervorrichtung durch den Bestrahlungsbereich steuerbar ist und von der Abtastbreite der besagten steuerbaren Mittel (6-9) und der Strahlkraft der besagten Teilchenbeschleunigungs-Vorrichtung (1-3) abhängt.
  11. Bestrahlungsanordnung gemäß einem der Ansprüche 9 oder 10, dadurch gekennzeichnet, dass die Transportvorrichtung ein Förderband, bestehend aus zwei Geweben (14,15) aus einem metallischen Drahtnetz, verbunden mit den besagten Bedienungsmitteln, entlang der Seiten verlängerbar und welches dazwischen die besagten Produkte festhält, wobei die besagten Gewebe (14,15) unabhängig voneinander, aber jeweils auf das andere abgestimmt, durch jeweilige Bedienungsmittel jeweils in einem geschlossenen Kreislauf bewegt werden, wobei die besagten Kreisläufe entlang zumindest der Strecke, die die Produkte durch die Bestrahlungsanordnung hindurch transportiert werden, miteinander verbunden sind, wobei die besagten Produkte durch Verklemmen zwischen den besagten Geweben an der besagten Transportvorrichtung fixiert sind, aufweist.
  12. Bestrahlungsanordnung gemäß Anspruch 1, dadurch gekennzeichnet,

    dass die besagten Teilchen Elektronen sind, welche bei der Bestrahlung in dem besagten Bestrahlungsbereich eine Energie im Bereich von 1,5 bis 2,5 MeV haben,

    dass zwei in dem Raum zwischen den jeweiligen Polstücken (9) der besagten Rückabklenkungs-Magneten angeordnete Teilchenstopper (10) aus wassergekühltem Kupfer oder Aluminium errichtet sind,

    wobei der von dem besagten Abtastmagneten einfallende Elektronenstrahl (a-f) auf den besagten Bestrahlungsbereich (13) abgelenkt wird und wobei zur gleichen Zeit, an der die Elektronenstrahlung den besagten Bestrahlungsbereich (13) ohne dabei absorbiert zu werden, passiert, auf den Teilchenstopper hin abgelenkt wird,

    dass der besagte Abtastmagnet den besagten Elektronenstrahl in einem Winkel, dessen Absolutwert in dem.Bereich von 15 - 45 Grad liegt, ablenkt, dass jedes Produkt unter der Bestrahlung in dem besagten Bestrahlungsbereich (13) derart positioniert wird, dass die Flächennormale der zu bestrahlenden Oberfläche in eine Richtung weist, die im Wesentlichen senkrecht zu der Richtung steht, die die Strahlungsachse unmittelbar vor dem Hindurchtreten des Strahls durch den besagten Abtastmagneten hat,

    dass die steuerbaren Mittel zusätzlich eine fokussierende Elektronenlinse (6) aufweisen, welche synchron mit dem besagten steuerbaren Abtastmagneten (7) steuerbar ist, um eine konstante Strahlgröße in dem besagten Bestrahlungsbereich zu erzielen;

    dass die besagte Trägervorrichtung (14-18) ein aus zwei Geweben (14,15) aus metallischem Drahtnetz gefertigtes Förderband umfasst, welches die besagten Produkte durch den besagten Bestrahlungsbereich (13) hindurch transportiert, die besagten Produkte währen des Transports durch die Bestrahlungsanordnung durch Verklemmen der Produkte zwischen den besagten Geweben (14,15) an der besagten Transportvorrichtung fixiert, und welche mit an den Seiten verlängerbaren Bedienungsmitteln verbunden ist, wobei die besagten Gewebe durch die jeweiligen Bedienungsmittel unabhängig voneinander, aber aufeinander abgestimmt, in geschlossenen Kreisläufen angetrieben werden, wobei die Kreisläufe zumindest entlang der Strecke, die die Produkte durch die Bestrahlungsanordnung hindurch transportiert werden, miteinander verbunden sind, und

    dass die vorbestimmte Bestrahlungsdosis dadurch erzielt wird, dass die Bedienungsgeschwindigkeit des besagten Förderbands von einer Position außerhalb des Bestrahlungsraums steuerbar ist und von der Abtastbreite der steuerbaren Mittel (6-9) und der Strahlkraft der besagten Teilchenbeschleunigungs-Vorrichtung abhängt.
  13. Verfahren zur Bestrahlung von Produkten in einer Bestrahlungskammer (4) mit geladenen Teilchen aus einer Teilchenbeschleunigungs-Vorrichtung (1-3) unter Verwendung steuerbarer Mittel (6-9) zum Abtasten des Strahls geladener Teilchen über die Oberfläche der besagten Produkte wechselseitig von wenigstens zwei Seiten, wobei das besagte Verfahren die Schritt umfasst:
    • Positionieren des besagten zu bestrahlenden Produkts in einem Bestrahlungsbereich,
    • Abtasten des besagten Strahls geladener Teilchen über die Oberfläche des besagten Produkts, wechselseitig von zumindest zwei Seiten,
    • Entfernen des besagten Produkts von dem besagten Bestrahlungsbereich,
    dadurch gekennzeichnet,

    dass das Abtasten durch den besagten Strahl durch Regeln der Ablenkung durch einen Abtastmagneten (7) auf zumindest einen Bereich von Ablenkungswinkeln sowie die Verwendung von zumindest zwei Rückablenkungs-Magneten (8,9) ausgeführt wird, und

    dass die Positionierung jedes Produkts in dem besagten Bestrahlungsbereich (13) derart ausgeführt wird, dass die Flächennormale der zu bestrahlenden Oberfläche in eine Richtung weist, die sich von der Richtung, die die Strahlachse unmittelbar vor Hindurchtreten des Strahls durch den Abtastmagneten (7) aufweist, wesentlich unterscheidet.
  14. Verfahren gemäß Anspruch 13, dadurch gekennzeichnet, dass die Absorption der Teilchen, welche ohne absorbiert zu werden durch die Bestrahlungsposition hindurchtreten, in Partikelstoppern (10) erfolgt.
  15. Verfahren gemäß einem der Ansprüche 13 oder 14, dadurch gekennzeichnet, dass die Regelung des besagten Abtastmagneten (7) die Veränderung des Endpunkts zumindest eines Bereichs von Ablenkungswinkeln umfasst, wobei die gewünschte Abtastbreite erzielt wird.
  16. Verfahren gemäß Anspruch 15, dadurch gekennzeichnet, dass die besagte Veränderung des Winkelbereichs des besagten Abtastmagneten (7) so durchgeführt wird, dass diejenigen Bereiche an Ablenkungswinkeln, die Teilchenwege erzeugen, durch die die besagten Produkte nicht bestrahlt werden, schnell durchlaufen oder vermieden werden.
  17. Verfahren gemäß einem der Ansprüche 13 bis 16,gekennzeichnet durch das Fokussieren des besagten Teilchenstrahls mit einer Linse für geladene Teilchen (6), wobei das Fokussieren synchron mit der Regelung des besagten Abtastmagneten (7) geregelt wird, so dass die Ausdehnung des Strahlflecks in Abtastrichtung über die zu bestrahlende Produktoberfläche konstant wird.
  18. Verfahren gemäß einem der Ansprüche 13 bis 17, dadurch gekennzeichnet, dass das Positionieren der zu bestrahlenden Produkte in dem besagten Bestrahlungsbereich und das Entfernen der besagten Produkte von dem besagten Bestrahlungsbereich durch Transport an einem Förderband (14-18) während des Betriebs der besagten Bestrahlungsanordnung ausgeführt wird.
  19. Verfahren gemäß Anspruch 18, gekennzeichnet durch Regeln der besagten Strahlungsdosis durch Regeln der Zuführgeschwindigkeit des besagten Förderbands.
  20. Verfahren gemäß Anspruch 19, dadurch gekennzeichnet, dass die besagte Regelung der Strahlungsdosis auf den Informationen über die Kraft der besagten Teilchenbeschleunigungs-Vorrichtung und die Breite des besagten Teilchenstrahls beruht.
  21. Anlage zur Erzeugung steriler Produkte, umfassend eine Bestrahlungsanordnung zur Bestrahlung von Produkten mit einem Strahl beschleunigter geladener Teilchen, wobei die Bestrahlungsanordnung eine Teilchenbeschleunigungs-Vorrichtung (1-3), eine Bestrahlungskammer (4) zur Aufnahme der Produkte zur Bestrahlung und mit einem Bestrahlungsbereich (13), in der die Bestrahlung der besagten Produkte stattfindet, aufweist, eine Trägervorrichtung (14-18) für die besagten zu bestrahlenden Produkte zur Bestrahlung der besagten Produkte von wenigstens zwei Seiten sowie steuerbare Mittel (6-9) zur Abtastung durch den besagten Strahl beschleunigter Teilchen über die Oberfläche der besagten Produkte, wechselseitig von wenigstens zwei Seiten, wobei die besagten steuerbaren Mittel einen steuerbaren Abtastmagneten (7) zur Ablenkung des besagten Teilchenstrahls und Rückablenkungsmittel (8,9) umfassen, wobei die besagten Rückablenkungsmittel Rückablenkungs-Magneten (8,9) umfassen, welche zwischen zumindest zwei Seiten des besagten Bestrahlungsbereichs (13) angeordnet sind,

    dadurch gekennzeichnet, dass

    die besagten Rückablenkungs-Magneten (8,9) eine geometrische Form aufweisen, durch die das magnetische Feld den besagten Teilchenstrahl (a-f), der von dem besagten Abtastmagneten aus einfällt, in einer Richtung, welche im wesentlichen senkrecht zu der Richtung der Strahlachse steht, die der Strahl unmittelbar vor dem Hindurchtreten durch den besagten Abtastmagneten hat, auf den Bestrahlungsbereich (13) hin ablenkt, wobei im wesentlichen alle Teilchenstrahlen sowohl durch die Ablenkung in den Abtastmitteln als auch durch die Rückablenkung in den Rückablenkungs-Magneten hindurchtreten.
  22. Verwendung einer Bestrahlungsanordnung gemäß einem der Ansprüche 1 - 12 oder eines Verfahrens gemäß einem der Ansprüche 13 - 20 zur Erzeugung steriler Produkte.
Anspruch[en]
  1. Irradiation arrangement for irradiation of products with a beam of accelerated charged particles and comprising a particle accelerator device (1-3), a radiation chamber (4) for reception of products for irradiation and comprising a radiation sector (13), in which the irradiation of said products takes place, a carrier device (14-18) for said products to be irradiated for irradiation of said products from at least two sides and controllable means (6-9) for scanning of said beam of charged particles over the surface of said products alternately from at least two sides, said controllable means comprising a controllable scanning magnet (7) for deflection of said particle beam and redeflection means (8, 9), said redeflection means comprising redeflection magnets (8, 9) positioned at at least two sides of said radiation sector (13),

    characterised in that

    said redeflection magnets (8, 9) have a geometrical shape which by its magnetic field deflects said particle beam (a-f), being incident from said scanning magnet, towards said radiation sector (13) in a direction substantially perpendicular to that direction the beam axis has immediately before the passage of the beam through said scanning magnet (7), whereby substantially all particle beams will pass through both the deflection in the scanning means and the redeflection in the redeflection magnets.
  2. Irraditaion arrangement according to claim 1, characterised by

       at least one absorption means for absorption of accelerated particles; and

       that said redeflection magnets (8, 9) has a geometrical shape which by its magnetic field, besides the deflection of said particle beam (a-f) towards said radiation sector (13) at the same time deflect that particle radiation which passes said radiation sector (13) without being absorbed, towards said absorption means.
  3. Irradiation arrangement according to claim 2, characterised in that said absorption means comprise/comprises a particle stopper (10), which is arranged in the space between the pole pieces (9) of said redeflection magnets.
  4. Irradiation arrangement according to claim 1 to 3, characterised in that each product during the irradiation is placed in the irradiation sector (13) with the normal of the surface to be irradiated directed in a direction substantially different from the original direction of the radiation beam.
  5. Irradiation arrangement according to claim 4, characterised in that each product during the irradiation is placed in the radiation sector (13) with the normal of the surface to be irradiated directed substantially perpendicular to the original direction of the radiation beam.
  6. Irradiation arrangement according to any of the claim 1 to 5,characterised in that said controllable means also comprises a focusing lens for charged particles (6), whereby the focusing lens (6) is controllable synchronous with the controllable scanning magnet (7) to give rise to a constant beam size in the radiation sector.
  7. Irradiation arrangement according to any of the claim 1 to 6,characterised in that said particles are electrons.
  8. Irradiation arrangement according to any of the claim 1 to 7,characterised in that the particle energy used at the irradiation in the radiation sector is selected from the range 1 to 10 MeV and preferably from the range 1.5 to 2.5 MeV.
  9. Irradiation arrangement according to any of the claim 1 to 8,characterised in that said carrier device (14-18) comprises a transport device (14, 15), which transports the products through the radiation sector (13), fixes the products to said transportation device (14, 15) during transport through said irraditaion arrangement and which is connected with actuating means (16, 17), whereby the actuation velocity is controllable from a position outside the radiation space.
  10. Irradiation arrangement according to claim 9, characterised in that a predetermined radiation dose is achieved by that the actuation velocity of said carrier device through the radiation sector is controllable and dependent of the scanning width of said controllable means (6-9) and the beam power of said particle acceleration device (1-3).
  11. Irradiation arrangement according to the claims 9 or 10,characterised in that the transport device comprises a conveyor belt consisting of two webs (14, 15) of metal wire net, connected with said actuating means, extended along the sides, and which in between fasten said products, said webs (14, 15) are driven, separately, but co-ordinated with each other, by respective actuating means in a closed loop each, said loops are connected to each other along at least the distance the products are transported through the irradiation arrangement, whereby said products are fixed to said transport device through jamming between said webs (14, 15).
  12. Irradiation arrangement according to claim 1,

    characterised in that

       said particles are electrons, which at the irradiation in said radiation sector has an energy selected from the range of 1.5 to 2.5 MeV;

       said redeflection magnets (8, 9), are substantially circular arch shaped,

       two particle stoppers (10), arranged in the space between respective pole pieces (9) of said redeflection magnets, which particle stoppers (10) are constituted of water cooled copper or aluminium;

       whereby the electron beam (a-f) being incident from said scanning magnet is deflected towards said radiation sector (13) at the same time as the electron radiation passing said radiation sector (13) without being absorbed, is deflected towards the particle stoppers (10);

       that said scanning magnet deflects said electron beam by an angle, the absolute value of which falls within the range of 15 - 45 degrees;

       that each product under irradiation is positioned in said radiation sector (13) with the normal of the surface to be irradiated directed in a direction substantially perpendicular to the direction that the radiation axis has immediately before the passage of the beam through said scanning magnet (7);

       that the controllable means also comprises a focusing electron lens (6), which is controllable synchronously with said controllable scanning magnet (7) to give rise to a constant beam size in said radiation sector,

       that said carrier device (14-18) comprises a conveyor belt made of two webs (14, 15 ) of metal wire net, which transports said products through said radiation sector (13), fixes said products to said transport device during transport through the irradiation arrangement by jamming the products between said webs (14, 15) and which is connected with at the sides extended actuating means, whereby said webs (14, 15) are driven, separately, but in co-operation with each other, by respective actuating means in a closed loop each, said loops are connected to each other along at least the distance the products are transported through the irradiation arrangement, and

       that a predetermined radiation dose is achieved by that the actuation velocity of said conveyor belt is controllable from a position outside of the radiation space and is dependent of the scanning width of the controllable means (6-9) and the beam power of said particle acceleration device (1-3).
  13. Method for irradiating products in a radiation chamber (4) with charged particles from a particle acceleration device (1-3) by using a controllable means (6-9) for scanning the beam of charged particles over the surface of said products alternately from at least two sides, whereby said method comprises the steps of:
    • positioning of said products to be irradiated in a radiation sector;
    • scanning of said beam of charged particles over the surface of said products alternately from at least two sides;
    • removing said products from said radiation sector,
    characterised in

       that said scanning of said beam is performed by controlling the deflection from a scanning magnet (7) to at least one range of deflection angles and use of redeflection from at least two redeflection magnets (8, 9), and

       that the positioning of each product in said radiation sector (13) is performed in such a way that the normal of the surface to be irradiated is directed in a direction substantially different from the direction that the beam axis has immediately before the passage of the beam through said scanning magnet (7).
  14. Method according to claim 13, characterised by absorbation of particles, passing the irradiation position without being absorbed, in a particle stopper (10).
  15. Method according to any of the claims 13 to 14, characterised in that said controlling of said scanning magnet (7) comprises changing of the end points for at least one range of deflection angles, whereby requested scanning width is achieved.
  16. Method according to claim 15, characterised in that said change in the angle range of said scanning magnet (7) is performed such that the ranges of deflection angles, giving rise to particle paths not irradiating said products, rapidly are passed or avoided.
  17. Method according to any of the claims 13 to 16, characterised by focusing said particle beam with a lens for charged particles (6), whereby the focusing is controlled synchronously with the control of said scanning magnet (7) so that the extension of the beam spot across the scanning direction over the irradiated product surface becomes constant.
  18. Method according to any of the claims 13 to 17, characterised in that the positioning of the products to be irradiated in said radiation sector and the removal of the products from said radiation sector is performed by transportation at a conveyor belt (14-18) during the operation of said irradiation arrangement.
  19. Method according to claim 18, characterised by controlling of said radiation dose by controlling the feeding velocity of said conveyor belt.
  20. Method according to claim 19, characterised in that said controlling of the radiation dose is based on information about the power of said particle accelerating device and the scanning width of said particle beam.
  21. System for production of sterile products comprising an irradiation arrangement for irradiation of products with a beam of accelerated charged particles, which irradiation arrangement comprises a particle accelerator device (1-3), a radiation chamber (4) for reception of products for irradiation and comprising a radiation sector (13), in which the irradiation of said products takes place, a carrier device (14-18) for said products to be irradiated for irradiation of said products from at least two sides and controllable means (6-9) for scanning of said beam of charged particles over the surface of said products alternately from at least two sides, said controllable means comprising a controllable scanning magnet (7) for deflection of said particle beam and redeflection means (8, 9), said redeflection means comprising redeflection magnets (8, 9) positioned at at least two sides of said radiation sector (13),

    characterised in that

    said redeflection magnets (8, 9) have a geometrical shape which by its magnetic field deflects said particle beam (a-f), being incident from said scanning magnet, towards said radiation sector (13) in a direction substantially perpendicular to that direction the beam axis has immediately before the passage of the beam through said scanning magnet (7), whereby substantially all particle beams will pass through both the deflection in the scanning means and the redeflection in the redeflection magnets.
  22. Use of an irradiation arrangement according to any of the claims 1-12 or of a method according to any of the claims 13-20, for production of sterile products.
Anspruch[fr]
  1. Agencement d'irradiation pour irradier de produits à l'aide d'un faisceau de particules chargées et accélérées, et comportant un dispositif accélérateur de particules (1 à 3), une chambre de rayonnement (4) pour réception de produits destinés à une irradiation, et comportant un secteur de rayonnement (13), dans lequel l'irradiation desdits produits a lieu, un dispositif de support (14 à 18) destinés auxdits produits devant être irradiés, pour une irradiation desdits produits à partir d'au moins deux côtés, et des moyens pouvant être commandés (6 à 9) pour balayer ledit faisceau de particules chargées au dessus de la surface desdits produits alternativement à partir d'au moins deux côtés, lesdits moyens pouvant être commandés comportant un aimant de balayage pouvant être commandé (7) pour déviation dudit faisceau de particules et des moyens de redéviation (8, 9), lesdits moyens de redéviation comportant des aimants de redéviation (8, 9) positionnés sur au moins deux côtés dudit secteur de rayonnement (13), caractérisé en ce que

       lesdits aimants de redéviation (8, 9) ont une forme géométrique qui, par son champs magnétique, dévie ledit faisceau de particules (a à f), étant incident en venant dudit aimant de balayage, en direction dudit secteur de rayonnement (13) dans une direction sensiblement perpendiculaire à la direction que l'axe de faisceau a immédiatement avant le passage du faisceau à travers ledit aimant de balayage (7), de sorte que sensiblement tous les faisceaux de particules vont passer à travers à la fois la déviation dans les moyens de balayage et la redéviation dans les aimants de redéviation.
  2. Agencement d'irradiation selon la revendication 1,caractérisé par

       au moins un moyen d'absorption pour absorption de particules accélérées, et

       caractérisé en ce que lesdits aimants de redéviation (8, 9) ont une forme géométrique qui, par son champ magnétique, en plus de la déviation dudit faisceau de particules (a à f) en direction dudit secteur de rayonnement (13), dévie en même temps ce rayonnement de particules qui passe ledit secteur de rayonnement (13) sans être absorbé en direction dudit ou desdits moyens d'absorption.
  3. Agencement d'irradiation selon la revendication 2,caractérisé en ce que ledit ou lesdits moyen(s) d'absorption comporte(nt) un bouchon de particules (10), qui est agencé dans l'espace situé entre les parties de pôle (9) desdits aimants de redéviation.
  4. Agencement d'irradiation selon les revendications 1 à 3, caractérisé en ce que chaque produit, durant l'irradiation, est placé dans le secteur de rayonnement (13), la perpendiculaire à la surface devant être irradiée étant dirigée dans une direction sensiblement différente de la direction d'origine du faisceau de rayonnement.
  5. Agencement d'irradiation selon la revendication 4,caractérisé en ce que chaque produit, durant l'irradiation, est placé dans le secteur de rayonnement (13), la perpendiculaire à la surface devant être irradiée étant dirigée de manière sensiblement perpendiculaire par rapport à la direction d'origine du faisceau de rayonnement.
  6. Agencement d'irradiation selon l'une quelconque des revendications 1 à 5, caractérisé en ce que lesdits moyens pouvant être commandés comportent également un objectif de mise au point pour des particules chargées (6), de sorte que l'objectif de mise au point (6) peut être commandé en synchronisation avec l'aimant de balayage pouvant être commandé (7) pour générer une taille de faisceau constante dans le secteur de rayonnement.
  7. Agencement d'irradiation selon l'une quelconque des revendications 1 à 6, caractérisé en ce que lesdites particules sont des électrons.
  8. Agencement d'irradiation selon l'une quelconque des revendications 1 à 7, caractérisé en ce que l'énergie de particules utilisée pendant l'irradiation dans le secteur de rayonnement est sélectionnée dans la plage allant de 1 à 10 MeV, et de préférence dans la plage allant de 1,5 à 2,5 MeV.
  9. Agencement d'irradiation selon l'une quelconque des revendications 1 à 8, caractérisé en ce que ledit dispositif de support (14 à 18) comporte un dispositif de transport (14, 15), qui transporte les produits à travers le secteur de rayonnement (13), fixe les produits sur ledit dispositif d'acheminement (14, 15) durant le transport à travers ledit agencement d'irradiation, et qui est connecté à des moyens d'actionnement (16, 17), de sorte que la vitesse d'actionnement peut être commandée à partir d'une position à l'extérieur de l'espace de rayonnement.
  10. Agencement d'irradiation selon la revendication 9,caractérisé en ce qu'une dose de rayonnement prédéterminée est obtenue par le fait que la vitesse d'actionnement dudit dispositif de support à travers le secteur de rayonnement peut être commandée et est dépendante de la largeur de balayage desdits moyens pouvant être commandés (6 à 9) et de la puissance de faisceau dudit dispositif d'accélération de particules (1 à 3).
  11. Agencement d'irradiation selon la revendication 9 ou 10, caractérisé en ce que le dispositif de transport comporte une courroie de transport constituée de deux bandes (14, 15) en mailles de fils de métal, connectées auxdits moyens d'actionnement, étendues le long des côtés, et qui fixent lesdits produits entre celles-ci, lesdites bandes (14, 15) sont entraînées séparément, mais coordonnées l'une avec l'autre par des moyens d'actionnement respectifs, chacune dans une boucle fermée, lesdites boucles étant connectées l'une à l'autre le long d'au moins la distance sur laquelle les produits sont transportés à travers l'agencement d'irradiation, de sorte que lesdits produits sont fixés sur le dispositif de transport par coincement entre lesdites bandes (14, 15).
  12. Agencement d'irradiation selon la revendication 1,caractérisé en ce que

       lesdites particules sont des électrons qui, au niveau de l'irradiation dans ledit secteur de rayonnement, ont une énergie sélectionnée dans la plage allant de 1,5 à 2,5 MeV,

       lesdits aimants de redéviation (8, 9) sont sensiblement en forme d'arc circulaire,

       deux bouchons de particules (10) sont agencés dans l'espace situé entre les parties de pôle respectives (9) desdits aimants de redéviation, lesquels bouchons de particules (10) sont constitués de cuivre refroidi à l'eau ou d'aluminium,

       de sorte que le faisceau d'électrons (a à f), étant incident à partir dudit aimant de balayage est dévié en direction dudit secteur de rayonnement (13) au même moment où le rayonnement d'électrons passant par ledit secteur de rayonnement (13) sans être absorbé, est dévié en direction des bouchons de particules (10),

       en ce que ledit aimant de balayage dévie ledit faisceau d'électrons d'un angle, dont la valeur absolue est dans la plage allant de 15 à 45 degrés,

       en ce que chaque produit sous irradiation est positionné dans ledit secteur de rayonnement (13), la perpendiculaire à la surface devant être irradiée étant dirigée dans une direction sensiblement perpendiculaire à la direction que l'axe de rayonnement a immédiatement avant le passage du faisceau à travers ledit aimant de balayage (7),

       en ce que les moyens pouvant être commandés comportent également un objectif électronique de mise au point (6), qui peut être commandé en synchronisation avec ledit aimant de balayage pouvant être commandé (7) pour créer une taille de faisceau constante dans ledit secteur de rayonnement,

       en ce que ledit dispositif de support (14 à 18) comporte une courroie de transport constituée de deux bandes (14, 15) en mailles de fils de métal, qui transporte lesdits produits à travers ledit secteur de rayonnement (13), fixe lesdits produits sur ledit dispositif de transport durant le transport à travers l'agencement d'irradiation en coinçant les produits entre lesdites bandes (14, 15), et qui est connectée aux moyens d'actionnement étendus sur les côtés, de sorte que lesdites bandes (14, 15) sont entraînées séparément, mais en coopération l'une avec l'autre, par des moyens d'actionnement respectifs, chacune dans une boucle fermée, lesdites boucles étant connectées l'une avec l'autre le long d'au moins la distance sur laquelle les produits sont transportés à travers l'agencement d'irradiation, et

       en ce qu'une dose de rayonnement prédéterminée est obtenue par le fait que la vitesse d'actionnement de ladite courroie de transport peut être commandée à partir d'une position à l'extérieur de l'espace de rayonnement, et est dépendante de la largeur de balayage des moyens pouvant être commandés (6 à 9) et de la puissance de faisceau dudit dispositif d'accélération de particules (1 à 3).
  13. Procédé pour irradier des produits dans une chambre de rayonnement (4) avec des particules chargées à partir d'un dispositif d'accélération de particules (1 à 3) en utilisant des moyens pouvant être commandés (6 à 9) pour balayer le faisceau de particules chargées au dessus de la surface desdits produits alternativement à partir d'au moins deux côtés, de sorte que ledit procédé comporte les étapes consistant à :
    • positionner lesdits produits devant être irradiés dans un secteur de rayonnement,
    • balayer ledit faisceau de particules chargées au dessus de la surface desdits produits alternativement à partir d'au moins deux côtés,
    • enlever lesdits produits dudit secteur de rayonnement,
       caractérisé en ce que

       ledit balayage dudit faisceau est réalisé en commandant la déviation à partir d'un aimant de balayage (7) vers au moins une plage d'angles de déviation et l'utilisation d'une redéviation à partir d'au moins deux aimants de redéviation (8, 9), et

       en ce que le positionnement de chaque produit dans ledit secteur de rayonnement (13) est réalisé de telle sorte que la perpendiculaire à la surface devant être irradiée est dirigée dans une direction sensiblement différente de la direction que l'axe de faisceau a immédiatement avant le passage du faisceau à travers ledit aimant de balayage (7).
  14. Procédé selon la revendication 13, caractérisé par une absorption de particules, passant la position d'irradiation sans être absorbées, dans un bouchon de particules (10).
  15. Procédé selon la revendication 13 ou 14,caractérisé en ce que ladite commande dudit aimant de balayage (7) comporte le changement des points d'extrémité d'au moins une plage d'angles de déviation, de sorte que ladite largeur de balayage exigée est obtenue.
  16. Procédé selon la revendication 15, caractérisé en ce que ledit changement dans la plage d'angles dudit aimant de balayage (7) est réalisé de telle sorte que les plages d'angles de déviation, générant lesdits trajets de particules n'irradiant pas les produits, sont rapidement passés ou évités.
  17. Procédé selon l'une quelconque des revendications 13 à 16, caractérisé par la mise au point dudit faisceau de particules avec un objectif pour des particules chargées (6), de sorte que la mise au point est commandée en synchronisation avec la commande dudit aimant de balayage (7), de sorte que l'extension du faisceau lumineux à travers la direction de balayage sur la surface de produit irradié devient constante.
  18. Procédé selon l'une quelconque des revendications 13 à 17, caractérisé en ce que le positionnement des produits devant être irradiés dans ledit secteur de rayonnement et l'enlèvement des produits dudit secteur de rayonnement sont réalisés par le transport au niveau d'une courroie de transport (14 à 18) durant le fonctionnement dudit agencement d'irradiation.
  19. Procédé selon la revendication 18, caractérisé par la commande de ladite dose de rayonnement en commandant la vitesse d'alimentation de ladite courroie de transport.
  20. Procédé selon la revendication 19, caractérisé en ce que ladite commande de la dose de rayonnement est basée sur des informations concernant la puissance dudit dispositif d'accélération de particules et la largeur de balayage dudit faisceau de particules.
  21. Système pour la production de produits stériles comportant un agencement d'irradiation pour irradier les produits par l'intermédiaire d'un faisceau de particules chargées accélérées, lequel agencement d'irradiation comporte un dispositif accélérateur de particules (1 à 3), une chambre de rayonnement (4) pour réception de produits destinés à une irradiation, et comportant un secteur de rayonnement (13), dans lequel a lieu l'irradiation desdits produits, un dispositif de support (14 à 18) destiné auxdits produits devant être irradiés, pour une irradiation desdits produits à partir d'au moins deux côtés, et des moyens pouvant être commandés (6 à 9) pour un balayage dudit faisceau de particules chargées au dessus de la surface desdits produits alternativement à partir d'au moins deux côtés, lesdits moyens pouvant être commandés comportant un aimant de balayage pouvant être commandé (7) destiné à dévier ledit faisceau de particules, et des moyens de redéviation (8, 9), lesdits moyens de nouvelle déviation comportant des aimants de nouvelle déviation (8, 9) positionnés sur au moins deux côtés dudit secteur de rayonnement (13),

       caractérisé en ce que

       lesdits aimants de redéviation (8, 9) ont une forme géométrique qui, par son champ magnétique, déforme ledit faisceau de particules (a à f), étant incident à partir dudit aimant de balayage, vers ledit secteur de rayonnement (13) dans une direction sensiblement perpendiculaire à la direction que l'axe de faisceau a immédiatement avant le passage du faisceau à travers ledit aimant de balayage (7), de sorte que sensiblement tous les faisceaux de particules vont passer à travers la déviation dans les moyens de balayage et la redéviation dans les aimants de nouvelle déviation.
  22. Utilisation d'un agencement d'irradiation selon l'une quelconque des revendications 1 à 12, ou d'un procédé selon l'une quelconque des revendications 13 à 20, pour la production de produits stériles.






IPC
A Täglicher Lebensbedarf
B Arbeitsverfahren; Transportieren
C Chemie; Hüttenwesen
D Textilien; Papier
E Bauwesen; Erdbohren; Bergbau
F Maschinenbau; Beleuchtung; Heizung; Waffen; Sprengen
G Physik
H Elektrotechnik

Anmelder
Datum

Patentrecherche

Patent Zeichnungen (PDF)

Copyright © 2008 Patent-De Alle Rechte vorbehalten. eMail: info@patent-de.com