Measuring tool for a radiation source and method for measuring radiation

Abstract

A measuring tool (1) for measuring the delivered dose of radiation emitted by at least one electron beam emitter (2a-b) in a radiation zone (2) for sterilizing packaging material that is subsequently formed into a package is provided. The measuring tool (1) comprises: at least one transducer (3) configured to convert one characteristic of the delivered dose of radiation into another characteristic; a frame (5) configured to hold the at least one transducer (3) and to insert the at least one transducer (3) into the radiation zone (2); and at least one connector (7) configured to allow a signal to be transmitted from the at least one transducer (3) to a readout system (9) remote from the radiation zone (2). Also provided are uses of the tool and a method for calibrating the dose of radiation emitted by at least one electron beam emitter (2a-b) in a radiation zone (2) for sterilizing packaging material that is subsequently formed into a package.

Description

Technical Field

[0001] The present invention relates to a measuring tool for measuring the delivered dose of radiation and a method for measuring radiation. In particular, the tool and the method are configured for use in a radiation zone for sterilizing a web of packaging material which is subsequently formed into a plurality of packages. Background Art

[0002] When the package is filled with a food product, it is desirable to sterilize the packaging material so that the pasteurized (or otherwise treated) product can be aseptically added before the package is sealed.

[0003] In order to extend the shelf life of food products, it is known to sterilize the packaging material before it is formed into a filled package. Different levels of sterilization may be selected depending on the required shelf life and whether distribution and storage is to be carried out at refrigerated or ambient temperatures. However, complete microbial kill is generally provided.

[0004] One sterilization approach is to irradiate the packaging material with electrons emitted from an electron beam unit. In order to achieve adequate sterilization while keeping the delivered dose of radiation to a minimum, the correct delivered dose is required. Therefore, during installation, and periodically about every few hundred hours (e.g., every 500-1000 hours) of operating time, the delivered dose of radiation is measured, followed by calibration and verification of the electron beam unit.

[0005] Some electron beam emitters include their own measurement equipment, but they have been found to be associated with some disadvantages. They may be inaccurate, may drift, and may be associated with undesirable noise levels. In order to minimize these problems, it may be beneficial to recalibrate this equipment regularly.

[0006] Transmitters also typically have recommended calibration settings, but these settings do not necessarily reflect the specific environment they will be used in during normal operation. Therefore, further measurement of the delivered dose of radiation is required.

[0007] Today, in food packaging, such as packaging liquid foods in individual packages, this measurement is performed with the aid of dosimetry with the aid of a radiochromic film attached to the packaging material. As the packaging material passes through an electron beam emitter, the film travels through the irradiation zone and the dose is then read manually by a calibrated measurement system. Data analysis must be done manually and therefore takes an undesirably long time. If any mistakes are made in this long and detailed process, this will not become apparent until after the process is complete.

[0008] Existing technology successfully measures the delivered dose of radiation. However, this wastes packaging material, takes a long time, and requires skilled technicians trained in dosimetry. Summary of the invention

[0009] It is an object of the present invention to at least partially overcome one or more of the above limitations of the prior art. In particular, it is an object to provide a measurement tool that is quick and easy to use and does not require interruption of the normal procedure.

[0010] According to a first aspect of the present invention, the above and other objects of the present invention are achieved in whole or in part by providing a measuring tool for measuring the delivered dose of radiation emitted by at least one electron beam emitter in a radiation zone for sterilizing packaging materials that are subsequently formed into a package. The measuring tool comprises: at least one transducer configured to convert one characteristic of the delivered dose of radiation into another characteristic; and a frame configured to hold at least one transducer and be inserted into the radiation zone; and at least one connector configured to allow a signal to be transmitted from at least one transducer to a readout system away from the radiation zone.

[0011] The advantage of the measurement tool is that it is quick and easy to use and does not require interruption of normal procedures.

[0012] At least one of the at least one transducer may be a thermocouple.

[0013] The advantage of thermocouples is that the radiation process generates a lot of heat, which means that the thermocouple will produce accurate measurements.

[0014] The at least one thermocouple may further be coupled to the at least one passive element.

[0015] The advantage of a passive component is that it can have a larger area than the transducer and does not directly expose the transducer to harmful radiation.

[0016] At least one of the at least one transducer may be a charge collector.

[0017] The advantages of charge collectors are ease of use and ease of transmission of measurement results.

[0018] The at least one charge collector may include at least one metallic or semiconductor element.

[0019] The advantage of a metal or semiconductor element is that it increases the efficiency of the charge collector.

[0020] The at least one charge collector may include at least one metal or semiconductor wire inserted into a hollow tube of a shield having at least one slit.

[0021] An advantage of the wire inserted into a hollow tube of a shield having at least one slit is that it provides a reliable measurement of the delivered dose of radiation while exposing the charge collector to a minimum amount of radiation.

[0022] At least one charge collector may be coated with a radiation resistant material.

[0023] The advantage of a radiation resistant material is that it will increase the durability and stability of the transducer.

[0024] At least one of the at least one transducer may be a scintillator.

[0025] The advantage of a scintillator is that it is well established for measuring radiation and will produce standardized and reliable measurements.

[0026] At least one scintillator may be coated with a radiation resistant material.

[0027] The advantage of a radiation resistant material is that it will increase the durability and stability of the transducer.

[0028] At least one of the at least one transducer may be a thin film solid state detector.

[0029] The advantage of thin-film solid-state detectors is that they can be made very small and thin.

[0030] A thin film solid state detector may comprise at least two active layers arranged at different distances from the electron beam emitter.

[0031] At least two active layers arranged at different distances from the electron beam emitter may provide a set of separate signals from which information about the energy of the incident radiation may be derived.

[0032] At least one thin film solid state detector may be coated with a radiation resistant material.

[0033] The advantage of a radiation resistant material is that it will increase the durability and stability of the transducer.

[0034] At least one transducer may be coupled to the cooling element.

[0035] The advantage of a cooling element is that the radiated area may have sufficiently high temperatures to damage the transducer and / or the frame.

[0036] A cooling element may be coupled to the passive element to be inserted into the radiation region and configured to maintain the passive element at a fixed temperature.

[0037] The advantage of keeping passive components at a fixed temperature is that they are easier to measure and standardize.

[0038] At least one of the transducers may further include a shield.

[0039] The advantage of a shield is that it will increase the durability and stability of the transducer and allow for directional or spatial measurements.

[0040] The shield may have at least one slit.

[0041] The advantage of the slit is that it allows for more directional spatial measurements and reduces the radiation that hits the transducer, thereby increasing the durability and stability of the transducer.

[0042] At least one of the transducers may further include a low energy filtering shield.

[0043] The advantage of a low energy filter shield is that it reduces noise.

[0044] At least one transducer may include at least one shielding layer directly exposed to incident radiation; and at least one active layer for detecting radiation; and at least one intermediate insulating layer between the shielding layer and the active layer.

[0045] An advantage of these layers is that they protect the measuring part of the transducer while remaining substantially flat. The shielding layer may preferably be metallic and / or grounded. The insulating layer may be electrically insulating and / or thermally insulating.

[0046] At least one of the transducers may be single-sided.

[0047] The advantage of a single-sided transducer is that it allows measuring only one electron emitter in a tunnel with electron emitters on multiple sides.

[0048] At least one of the transducers may be double-sided.

[0049] An advantage of a double-sided transducer is that it allows measuring multiple electron emitters in a tunnel having electron emitters on multiple sides.

[0050] At least one transducer and the frame may be substantially planar in a common plane.

[0051] The advantage of being substantially flat is that the tool can then fit in any radiation area.

[0052] The frame may include baffles that allow alternating exposure of the at least one transducer to the radiation area.

[0053] An advantage of the baffle is that it allows at least one transducer to be exposed to radiation only after the environment has stabilized.

[0054] The frame may include a motor configured to provide automatic insertion of the at least one transducer into the radiation region.

[0055] The advantage of a motor is that it allows for automation or assistance and precise exposure time of the tool in the radiation zone to extend the durability of the tool.

[0056] The frame may include a handle configured to assist during insertion of the at least one transducer into the radiation zone.

[0057] The advantage of the handle is that it makes the tool easier to use.

[0058] The handle may further be configured to stabilize the frame during use.

[0059] The advantage of stabilization is that it allows for more reliable measurements.

[0060] The tool may further include a plurality of transducers arranged in a two-dimensional matrix with a predetermined spatial resolution.

[0061] An advantage of transducers arranged in a two-dimensional matrix with a predetermined spatial resolution is that it allows two-dimensional spatial measurements.

[0062] The readout system may be configured to provide a spatial map of a profile of radiation emitted by the at least one electron beam emitter.

[0063] The advantage of this spatial map is that it allows for more precise diagnostics and calibration of the electronic emitter.

[0064] According to a second aspect, use of the measuring tool according to the first aspect is provided for measuring a radiation dose emitted by at least one electron beam emitter in an irradiation zone.

[0065] The advantage of using measurement tools in this way is that they are quick and easy to use and do not require interruption of normal procedures.

[0066] According to a third aspect, there is provided a method for calibrating a radiation dose emitted by at least one electron beam emitter in a radiation zone for sterilizing packaging material to be made into packaging. The method comprises the steps of inserting at least one transducer into the radiation zone using a frame; measuring a delivered dose of radiation emitted in the radiation zone using at least one transducer; and transmitting the measurement result to a readout system remote from the radiation zone using at least one connector.

[0067] The advantage of this method is that it is quick and simple and does not require interruption of normal procedures.

[0068] The method may further comprise the step of removing the packaging material from the radiation area prior to inserting the at least one transducer.

[0069] The advantage of removing the packaging material is that the packaging material may interfere with the measurement and removing it makes the appearance more similar to the actual production environment.

[0070] The insertion step can be performed automatically.

[0071] The advantage of automatic insertion is that it reduces the possibility of human error.

[0072] Other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Embodiments of the invention will now be described by way of example and with reference to the accompanying schematic drawings, in which:

[0074] Figure 1 is a perspective view of a measurement tool according to one embodiment;

[0075] Figures 2a to 2c are perspective views of various transducers according to several different embodiments;

[0076] Figures 3a to 3b is a side view of various transducers in use according to various embodiments;

[0077] Figure 4 is a side view of a measurement tool in use according to one embodiment; and

[0078] Figure 5 is a schematic diagram of a method for sterilizing packaging materials according to one embodiment. DETAILED DESCRIPTION

[0079] refer to Figure 1 , showing a measuring tool 1. The measuring tool 1 is configured to measure the radiation area 2 ( Figure 4 The delivered dose of radiation emitted in ).

[0080] The measuring tool 1 comprises five transducers 3, but any number is possible. The transducers 3 are configured to convert one characteristic of the delivered dose of radiation into another characteristic. When more than two transducers 3 are used, a total measured characteristic value or an average value can be used. In the embodiment shown, all five transducers 3 are charge collectors that convert the transmitted power of the delivered dose of radiation into an electric charge.

[0081] By using many transducers 3 with relatively high spatial resolution, the measured delivered dose of radiation can be used as a spatial map of the emitted radiation profile in a similar manner to CCD light sensors used in cameras.

[0082] In one embodiment, a plurality of transducers 3 having a predetermined spatial resolution are arranged in a two-dimensional matrix. The predetermined resolution is high enough to distinguish each transducer 3 in the matrix from each other.

[0083] These transducers 3 can measure a two-dimensional map of the radiation profile emitted by at least one electron beam emitter 2a-b. This spatial map can be displayed on a remote readout system 9, as will be described later.

[0084] The charge collector 3 comprises charge collecting elements which may be made of metal or semiconductor material. These charge collecting elements may be arranged as wires or plates. In order to enhance the stability of the charge collector 3 over time, these charge collecting elements may be coated with radiation resistant material.

[0085] At least one charge collector 3 may comprise at least one metal or semiconductor wire inserted into a hollow tube of a shield 11 having at least one slit. This is advantageous in that this provides a reliable measurement of the delivered dose of radiation while exposing the charge collector 3 to a minimum amount of radiation.

[0086] The transducer 3 is configured to be insertable into the radiation region 2. The radiation region 2 is substantially flat, which means that the transducer 3 also needs to be substantially flat. The radiation region 2 may be, for example, a radiation tunnel formed by two or more electron emitters 2a-b or an immediate area just in front of one electron emitter 2a.

[0087] The transducer 3 is arranged in a frame 5 which holds the transducer 3 and is configured for inserting the transducer 3 into the radiation region 2 .

[0088] The frame 5 may further be configured to be inserted into the radiation region 2 together with the transducer 3. Thus, the frame 5 is substantially flat at least in the portion to be inserted into the radiation region 2. The frame 5 may have any substantially flat shape, such as a rectangular, oval or slightly concave circular shape. The transducers 3 held in place by the frame 5 are arranged in the frame so that they are substantially flat in a plane P common to the frame 5 (see FIG. 2 ). Figure 4 ).

[0089] The transducer 3 may include a shield 11 (see Figure 2b ), to direct the radiation measurement in a specific direction, for example, of only one electron emitter 2a. The shield 11 may, for example, comprise a shielding metal, such as stainless steel, lead, tungsten, tin, antimony and / or bismuth. The shield 11 may be substantially flat or slightly concave or convex in a plane P common to the frame 5.

[0090] By providing a shield 11 on one side of the transducer 3, the transducer 3 can be said to be single-sided. By not providing a shield 11 on at least the opposite side of the transducer 3, the transducer 3 can be said to be double-sided. A plurality of single-sided transducers 3 can be arranged in the frame 5 to either all face one side, or alternate between different sides.

[0091] The shield 11 may further comprise at least one slit. The slit allows only a portion of the total emitted radiation to reach the transducer 3. As long as this portion is sufficient to provide a clear reading, the reduced radiation exposure will enhance the stability of the transducer 3 over time.

[0092] By providing the shielding 11 on all sides of the transducer 3 and providing at least one slit on only one side, the transducer 3 can be said to be single-sided. The at least one slit can be arranged on the opposite side of the complete shielding of the single-sided transducer 3, which will turn it into a double-sided transducer 3 as radiation is now allowed to reach the transducer from both sides.

[0093] The shield 11 may be a hollow tube having at least one slit in the tube facing the direction of incident radiation.

[0094] The transducer 3 may additionally or alternatively include a filter, such as a low energy filter shield 11. The low energy filter shield 11 filters low energy electrons that generate noise in the measurement of the radiation dose. The filter may be a film and / or coating of a shielding material operatively connected to a ground voltage. Any component that is grounded may be separated from the measuring portion of the transducer 3, for example, by air, an electrical insulating layer, and / or a thermal insulating layer.

[0095] The frame 5 may be made of any material suitable for insertion into or near the radiation zone 2 and may be made in one or more pieces.

[0096] The frame 5 may further comprise a handle 8. The handle 8 is configured to assist during the insertion of the at least one transducer 3 into the radiation zone 2. The handle 8 is arranged in a portion of the frame 5 which is not inserted into the radiation zone 2 and therefore does not have to be substantially flat on the same plane as the frame 5. The handle 8 may have any shape suitable for easy manipulation of the frame 5 manually or by a machine, such as an opening, a groove or an end with high friction.

[0097] The handle 8 may additionally or alternatively be configured to stabilize the frame 5 when in use. This may be achieved by cooperating with a stabilizer or bracket arranged near the radiation area 2 ( Figure 4 shown).

[0098] The measuring tool 1 further comprises at least one connector 7, which is configured to allow the signal to be transmitted from the transducer 3 to a readout system 9 remote from the radiation area 2. In the embodiment shown with a charge collector 3, the transmitted signal is an electric charge, and the current is interpreted as the amount of delivered dose of radiation using known methods. The calculated delivered dose is then displayed on the readout system 9.

[0099] The connector 7 can be, for example, an electric wire, an optical fiber, a thermal conductor or an optical beam, which has a corresponding receiver at the end of the readout system 9 .

[0100] The readout system 9 may be any type of display, such as a screen, projection or hologram; or other type of interface, such as a speaker or a colored light. The readout system 9 may include any number of converters and processors for interpreting the received signals, such as a converter between thermal energy and electronic signals, and a processor for interpreting the converted electronic signals as the amount of delivered dose of radiation using known methods. At least the interface should be visible, audible or interactive outside the radiation area 2 in order to protect any user from unnecessary exposure to radiation.

[0101] The readout system 9 may be included in the filling machine that performs the irradiation. It may be beneficial to integrate the readout system 9 and the control to change 150 at least one setting of at least one electron beam emitter 2a-b. The changed setting may be, for example, current, intensity, energy, exposure time, or any other setting that affects the emitted radiation. At least one setting of at least one electron beam emitter 2a-b may be configured to vary linearly with respect to the processing speed of the packaging material.

[0102] In order to establish standard values ​​for the correlation of the received signal and the delivered dose of radiation, existing techniques can be used.

[0103] Reference Figures 2a to 2c , different embodiments of the transducer 3 arranged in the frame 5 will be described. Figure 2a Four thin film solid state detectors 3 are shown, which are partly arranged inside the frame 5 and partly extend outside the frame 5. By extending the transducers 3 outside the frame 5, the frame 5 does not need to be inserted into the radiation area 2 where the transducers 3 are to be inserted.

[0104] The thin film solid state detector 3 converts the emitted radiation of the delivered dose of radiation into an electric charge. The charge is then transferred in the manner previously discussed using the connector 7. The thin film solid state detector 3 may be made of at least one active layer of a thin film of a doped or undoped semiconductor that converts radiation in a known manner. The semiconductor used may, for example, be selected from the group consisting of: silicon, germanium, silicon carbide and III-IV semiconductor compounds, such as gallium arsenide or indium phosphide.

[0105] Some thin film solid state detectors 3 may be coated with radiation resistant materials in order to enhance stability over time as previously described and to filter out noise signals.

[0106] Some thin film solid state detectors 3 may be arranged as multi-layer units, in which different active layers are separated by insulating and / or passive layers. Different active layers at different depths from the radiation source surface may provide a set of separate signals from which information about the energy of the incident radiation may be derived.

[0107] Figure 2a Further shown is a frame 5 comprising a baffle 12 allowing the at least one transducer 3 to be alternately exposed to the radiation zone 2. The baffle 12 in this embodiment comprises two movable radiation shielding plates 11, but it may comprise a set of any number of shielding units of any shape, at least one of which is movable. The baffle may be manually or automatically operated to move from a first position ( 10 ) in which the shielding plates 11 block radiation from reaching the at least one transducer 3. Figure 2a The shield 11 is moved between a position in which the shield 11 does not block radiation and a position in which the shield 11 does not block radiation. The advantage of the shield 12 is that it allows at least one transducer 3 to be exposed to radiation only after the environment has stabilized.

[0108] Figure 2a It is further shown that one of the transducers 3 is coupled to a cooling element 4. The cooling element 4 may be, for example, a fan, a plate heat exchanger, or any other suitable element. The transducer 3 coupled to the cooling element 4 may be any type of transducer 3, and any number of cooling elements 4 may be coupled to the transducer 3, and vice versa. The cooling element 4 may enhance the dissipation of the collected transmission power of the delivered dose of radiation.

[0109] In embodiments having at least one cooling element 4, the cooling element 4 may be coupled to one or more passive elements 10, such as a metal plate, to be inserted into the radiation region 2. The cooling element 4 may then be configured to maintain the one or more passive elements 10 at a fixed temperature while being exposed to radiation from the radiation region 2. By measuring the power consumed by the cooling element 4 to maintain the temperature fixed, and using a connector 7 connected via the transducer 2 or directly to the cooling element 4, the delivered dose of radiation may be calculated and displayed in a readout system 9.

[0110] Figure 2b Three scintillators 3 and two thin-film solid-state detectors 3 are shown arranged at different angles in a frame 5. The transducer 3 also includes a shield 11 with slits; however, it should be noted that the shield 11 with or without slits can be used for any suitable type of transducer 3. Different angles may affect the delivered dose of the measured radiation, so by measuring at different angles, a more representative average value can be calculated.

[0111] The scintillator 3 converts the radiation of the delivered dose of the emitted radiation into an optical signal. The optical signal is then transmitted through an optical fiber or through the air using a connector 7 and then received at the end of a readout system 9. The received optical signal is interpreted using its intensity and / or frequency to correlate with the amount of delivered dose of the radiation using mathematics or comparison with known values ​​collected using prior art methods. As previously mentioned, the optical signal may also be converted into an electrical signal before being transmitted using the connector 7.

[0112] The scintillator 3 may be, for example, an organic scintillator, a plastic scintillator, an inorganic scintillator, a gaseous scintillator, a glass scintillator or any suitable scintillator.

[0113] Parts of the scintillator 3 may be coated with radiation-resistant material in order to enhance the stability of the signal over time and filter out noise.

[0114] Figure 2c Four thermocouples 3 are shown, which include metal plates 10 arranged in a frame 5. The thermocouples 3 can convert the emitted power of the delivered dose of radiation into heat. The heat can then be directly transferred to a readout system 9 using a thermally conductive connection 7, or converted into an electrical or optical signal before transmission as previously described. As previously described, the heat is interpreted by measuring the temperature of the heating medium and correlating it with the delivered dose of radiation.

[0115] The thermocouple 3 may be, for example, a junction thermocouple, a nickel alloy thermocouple, a platinum / rhodium alloy thermocouple, a tungsten / rhenium alloy thermocouple or any other suitable thermocouple or thermopile, which is preferably suitable for use in a wide temperature range of several hundred Kelvin.

[0116] The thermocouple 3 may be configured to be directly exposed to the radiation or may further include at least one passive element 10, such as Figure 2c The metal plate shown. Passive components 10 can further increase the strength of the signal.

[0117] As previously mentioned, the thermocouple 3 may alternatively or additionally be configured to convert heat into electricity to be transmitted.The measured heat may be generated by the at least one passive element 10 when the at least one passive element 10 is radiated.

[0118] Figures 2a to 2c The embodiments shown in are examples only and the skilled person will realize that any number and combination of transducers 3 arranged in various ways are possible within the scope of the subject matter defined in the appended claims.

[0119] Figure 3a An embodiment of a transducer 3 comprising layers is shown. The outermost layer is at least one shielding layer 11 which is directly exposed to the incident radiation. The shielding layer 11 may comprise any material suitable for blocking radiation. The shielding layer 11 may additionally be positioned as an inner layer.

[0120] Figure 3aThe transducer 3 further comprises at least one active layer 13. The active layer 13 is an active component of the transducer 3, which is configured to detect and convert radiation. The active layer 13 may be, for example, a metal plate or wire, a doped semiconductor or a luminescent material. At least two active layers 13 may be arranged at different distances from the at least one electron beam emitter (2a-b) to provide a set of separate signals from which information about the energy of the incident radiation may be derived.

[0121] The transducer 3 may further comprise at least one intermediate layer 14. At least one intermediate layer 14 is arranged between the shielding layer 11 and the active layer 13, but the intermediate layer 14 may also be arranged between two active layers 13, and several intermediate layers 14 may be provided between each set of other layers. The intermediate layer may be insulated in some way, depending on the type of transducer 3. If the transducer 3 is a thermocouple, a thermal insulator may be beneficial. If the transducer 3 is a charge collector, an electrical insulator may be beneficial. If the transducer 3 is a scintillator, an optical insulator may be beneficial. Thus, the intermediate layer 14 may comprise a variety of materials including gas, plastic, silicon, metal, semiconductor or liquid.

[0122] Figure 3b Another embodiment of a transducer 3 comprising layers is shown. The layers are not planar. The active layer 13 is a wire inserted into a hollow tube of a shielding layer 11. The shielding layer 11 may or may not include at least one slit. Between the shielding layer 11 and the wire 13 is an intermediate layer 14 consisting of air.

[0123] Figure 4 The measuring tool 1 is shown in use. The measuring tool 1 is inserted into the upper part of the irradiation area 2 and irradiated by two electron beam emitters 2a-b. There may be any number of electron beam emitters 2a-b and many different implementations of the electron beam emitters 2a-b are possible.

[0124] The measuring tool 1 can additionally or alternatively be inserted into the bottom of the irradiation area 2. The measuring tool 1 can be inserted during normal operation or preferably in the absence of packaging material in the irradiation area 2.

[0125] The frame 5 needs to be substantially flat enough to fit in the radiation region 2 as seen, and preferably holds at least one transducer 3 so that radiation emitted by the electron beam emitters 2a-b can be measured by the transducer 3. The width of the frame 5 at its flattest part is 10-30 mm, preferably 20 mm. Figure 4The frame 5 comprises a motor 6 configured to provide automatic insertion of at least one transducer 3 into the radiation region 2. The motor 6 and the insertion movement can be implemented in a variety of ways known to the skilled person to expose at least one transducer 3 to the radiation region 2, such as extending at least one transducer 3 out of the frame 5, moving the frame 5 itself, or actuating the baffle 12.

[0126] Figure 5 A schematic diagram of a method 100 for calibrating the radiation dose emitted by at least one electron beam emitter 2a-b in an irradiation zone 2 for sterilizing packaging material subsequently formed into packaging is shown. Calibrating the radiation dose may be construed as ensuring that the delivered dose of radiation is within a predetermined acceptable range.

[0127] Figure 5 The method 100 shown is only an example. The method 100 includes several steps 110 to 150. These steps can be performed in any order, repeated any number of times or skipped completely. Therefore, each step will be described separately.

[0128] The removing step 110 comprises removing 110 the packaging material from the radiation area 2 before inserting the at least one transducer 3. This step 110 may be performed manually or automatically. By removing the packaging material before measuring the delivered dose of radiation, a more accurate measurement environment may be obtained.

[0129] The insertion step 120 includes inserting at least one transducer 3 into the radiation region 2 using the frame 5. This step 120 can be performed manually or automatically, for example using the motor 6 as described above. The frame 5 may need to be rotated in order to fit into the radiation region 2. In order to obtain a strong signal, it may be beneficial to align the frame 5 with the electron beam emitters 2a-b. Removing the frame 5 and / or at least one transducer 3 from the radiation region 2 is not described in detail, but the skilled person will understand that anything inserted into the radiation region 2 will be removed at some point.

[0130] The measuring step 130 comprises measuring the delivered dose of the radiation emitted in the radiation zone 2 using at least one transducer 3. The different measuring functions of the transducer 3 have been described in detail above and will not be repeated here.

[0131] The transmission step 140 comprises transmitting the measurement results to a readout system 9 remote from the radiation area 2 using at least one connector 7. The readout system 9 then displays these measurement results. The display may be visual, audible or perceived using any other sense. The displayed measurement results may be detailed as a graph of the emitted radiation profile, an average, a total or a list of all completed measurement results. The displayed measurement results may additionally or alternatively include: if the measurement results deviate from a predetermined acceptable range, a warning is displayed.

[0132] The transmitting step 140 may be arranged to transmit information only if the measurement results deviate from a predetermined acceptable range. The predetermined acceptable range may be set using industry expertise or previous measurement results and evaluations.

[0133] The changing step 150 comprises changing at least one setting of at least one electron beam emitter 2a-b. The changed setting may be, for example, intensity, energy, exposure time or any other setting affecting the emitted radiation.

[0134] Preferably, the changing step 150 is performed only if the displayed measurement deviates from a predetermined acceptable range. If the delivered dose of radiation measured at 130 is below the predetermined acceptable range, the changed settings preferably increase the emitted radiation, and vice versa.

[0135] Figure 5 The illustrated embodiment of the method 100 has four steps 110 to 150. First, the insertion step 120 is performed, and then the measurement step 130 is performed. Next, the transmission step 140 is performed, and if the measurement result of the transmission deviates from the predetermined acceptable range, the change step 150 is performed. In order to ensure that the change step 150 has the desired effect of setting the delivered dose of radiation within the predetermined acceptable range, the measurement step 130 and the transmission step 140 are repeated. If the delivered dose of radiation is within the predetermined acceptable range, the method 100 is completed and the radiation dose emitted by the at least one electron beam emitter 2a-b is calibrated. If not, the steps 130 to 150 are repeated until the delivered dose of radiation is within the predetermined acceptable range.

[0136] From the above description, although various embodiments of the invention have been described and shown, the invention is not restricted thereto but may also be embodied in other ways within the scope of the subject matter defined in the appended claims.

Claims

1. A measuring tool (1) for measuring the delivered dose of radiation emitted by at least one electron beam emitter (2a-b) in a substantially flat radiation area (2) for sterilizing packaging material subsequently formed into packaging, the measuring tool (1) comprising: at least one substantially planar transducer (3) configured to convert one characteristic of the delivered dose of radiation into another characteristic and removably insertable into the radiation area (2) from which the packaging material has been removed; a frame (5) configured to hold the at least one transducer (3) and to insert the at least one transducer (3) into the radiation zone (2) from which the packaging material has been removed, wherein the at least one transducer (3) and the frame (5) are substantially flat in a common plane; as well as At least one connector (7) configured to allow transmission of signals from the at least one transducer (3) to a readout system (9) remote from the radiation area (2).

2. The measuring tool (1) according to claim 1, wherein: At least one of the at least one transducer (3) is a thermocouple coupled to at least one metal plate (10).

3. The measuring tool (1) according to claim 1 or 2, wherein: At least one of the at least one transducer (3) is a charge collector comprising at least one metallic or semiconductor element (13).

4. The measuring tool (1) according to claim 3, wherein: At least one charge collector (3) comprises at least one metal or semiconductor wire (13) inserted into a hollow tube of a shield (11) having at least one slit.

5. The measuring tool (1) according to claim 1 or 2, wherein: At least one of the at least one transducer (3) is a scintillator.

6. The measuring tool (1) according to claim 1 or 2, wherein: At least one of the at least one transducer (3) is a thin film solid state detector.

7. The measuring tool (1) according to claim 6, wherein: At least one thin film solid-state detector (3) comprises at least two active layers (13) which are arranged at different distances from the electron beam emitters (2a-b).

8. The measuring tool (1) according to claim 1 or 2, wherein: At least one transducer (3) is coupled to a cooling element (4); The cooling element (4) is coupled to a metal plate (10) to be inserted into the radiation area (2), and is configured to maintain the metal plate (10) at a fixed temperature.

9. The measuring tool (1) according to claim 1 or 2, wherein: At least one transducer (3) further comprises a shield (11) having at least one slit.

10. The measuring tool (1) according to claim 1 or 2, wherein: At least one transducer (3) comprises: at least one shield (11) layer directly exposed to incident radiation; at least one active layer (13) for detecting radiation; and At least one intermediate (14) insulating layer is provided between the shield (11) layer and the active layer (13).

11. The measuring tool (1) according to claim 1 or 2, wherein: The frame (5) comprises baffles (12) which allow at least one transducer (3) to be exposed alternately to the radiation area (2).

12. The measuring tool (1) according to claim 1 or 2, wherein: The frame (5) comprises a motor (6) configured to provide automatic insertion of the at least one transducer (3) into the radiation zone (2).

13. The measuring tool (1) according to claim 1 or 2, wherein: The frame (5) comprises a handle (8) configured to assist during the insertion of the at least one transducer (3) into the radiation zone (2) and to stabilize the frame (5) during use.

14. Use of a measuring tool (1) according to the preceding claim 1 or 2 for measuring a radiation dose emitted by at least one electron beam emitter (2a-b) in an irradiation region (2).

15. A method (100) for calibrating a radiation dose emitted by at least one electron beam emitter (2a-b) in a substantially flat radiation area (2) for sterilizing packaging material subsequently formed into packaging; the method (100) using a measuring tool (1) as claimed in any one of claims 1 to 13, the method (100) comprising the following steps: inserting (120) at least one substantially flat transducer (3) of the measuring tool (1) into the substantially flat radiation area (2) using a frame (5) of the measuring tool (1); measuring (130) a delivered dose of radiation emitted in the radiation region (2) using the at least one transducer (3); as well as transmitting (140) the measurement results to a readout system (9) remote from the radiation area (2) using at least one connector (7); The method (100) further comprises the following steps: The packaging material is removed from the radiation area prior to inserting the at least one transducer (3).

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