Plasma source for generating a disinfecting and / or sterilizing gas mixture

Abstract

A plasma source for generating a disinfecting and / or sterilizing gas mixture, comprising an ionization chamber having a dielectric tubular section, a flow inlet for feeding a gas or a gas mixture into the chamber, a flow outlet for discharging the disinfecting and / or sterilizing gas mixture out of the chamber, a first electrode located inside the dielectric tubular section, and a second electrode located outside the dielectric tubular section. The plasma source has a high voltage power supply having high voltage output terminals, wherein an electrical conductor connects the output terminals to the first electrode or the second electrode, and a forced gas cooling system for cooling the ionization chamber.

Description

Technical Field

[0001] This application relates to the use of plasma for sterilization and / or disinfection of medical devices, such as dental instruments. More generally, this application relates to methods and apparatus for generating a mixture of sterilizing and / or disinfecting gases. Background Technology

[0002] Reusable medical devices are those that healthcare providers can reuse to diagnose and / or treat multiple patients. Examples of reusable medical devices include those used in dental care, such as scalpels, syringes, endoscopes, mirrors, drills, dental hooks, discs, handpieces, chisels, turbines, files, drills, etc.

[0003] When used on patients, reusable devices can become contaminated and soiled with blood, tissue, and other biological debris such as microorganisms. To avoid any risk of infection from contaminated devices, reusable devices can be sterilized. Sterilization results in the medical device being safe for use on the same patient more than once or on more than one patient. Proper sterilization of reusable medical devices is crucial for protecting patient safety.

[0004] Various sterilizing agents can be used for the sterilization of medical devices. Historically, steam or hydrogen peroxide has been frequently used. More recently, plasma devices have been used to ionize gases or gas mixtures, with the ionized gas serving as a sterilizing agent. Electrons in the plasma influence gas molecules, causing these molecules to dissociate and ionize, resulting in a mixture of reactive substances. Direct exposure of medical devices to plasma, or (partially) exposure of medical devices to recombinant plasma (sometimes called afterglow), is known; see, for example, S. Moreau et al., “Using the flowing afterglow of aplasma to inactivate Bacillus subtilis spores: Influence of the operating conditions”, J. Appl. Phys. Vol. 88, No. 2, July 15, 2000.

[0005] Several attempts have been made to improve plasma sterilization. US2011 / 0027125A1 discloses a system that includes a chamber and a plasma generator used in conjunction with a hydrogen peroxide solution to generate free radicals.

[0006] It is also known to use atmospheric or ultra-atmospheric plasma sources.

[0007] Plasma sources may have the following disadvantages: the composition of disinfectants and / or sterilizing agents produced by generating at least partially ionized gas mixtures can vary significantly with changes in plasma temperature and / or pressure. Summary of the Invention

[0008] The object of this invention is to provide an improved plasma source for generating a mixture of disinfecting and / or sterilizing gases.

[0009] According to a first aspect, this document provides a plasma source for generating a disinfecting and / or sterilizing gas mixture. The plasma source includes an ionization chamber. The ionization chamber includes a dielectric tubular portion. The dielectric tubular portion may form the wall of the ionization chamber. The ionization chamber includes an inlet for supplying a gas or gas mixture into the chamber. In the ionization chamber, the gas or gas mixture is converted into a disinfecting and / or sterilizing gas mixture. The ionization chamber includes an outlet for discharging the disinfecting and / or sterilizing gas mixture from the chamber. The inlet may be located at a first end of the tubular portion. The outlet may be located at a opposite second end of the tubular portion. Thus, the gas or gas mixture can flow through the tubular portion. The ionization chamber includes a first electrode located inside the dielectric tubular portion and a second electrode located outside the dielectric tubular portion. The first electrode may extend longitudinally within the tubular portion, for example, along the axis of the tubular portion. The second electrode may be formed on the outer surface of the tubular portion. The second electrode may be a separate component, such as a metal sheet. The second electrode may also be a conductive layer coated on the outer surface of the tubular portion, such as a metal layer (plasma) deposited on the outer surface. The plasma source includes a high-voltage power supply with a high-voltage output terminal, wherein an electrical conductor connects the output terminal to either a first electrode or a second electrode. The high-voltage terminal may be connected to the first electrode. The second electrode may be connected to electrical ground. Preferably, the length of the electrical conductor is less than 50 cm. The plasma source includes a forced gas cooling system for cooling the ionization chamber.

[0010] The plasma source is configured to generate a disinfecting and / or sterilizing gas mixture. It should be understood that, depending on the environment, generating a disinfecting gas mixture suitable for disinfecting objects, in which most microorganisms are killed, although not all microorganisms need to be killed. In other cases, it is preferable to generate a sterilizing gas mixture suitable for sterilizing objects, in which substantially all microorganisms are killed.

[0011] It has been found that cooling an ionization chamber with a forced gas, such as forced air, for example, the tubular portion of the ionization chamber, provides a particularly good mixture of disinfecting and / or sterilizing gases, especially when combined with relatively short electrical conductors.

[0012] Forced gas cooling can be considered to improve the quality of the sterilizing and / or disinfecting gas mixture by beneficially influencing the temperature stability of the plasma source. In this respect, gas cooling has been found to be superior to liquid cooling, such as water cooling. Liquid cooling can be considered to have a greater corrosive effect on parts of the plasma source than gas cooling, thus causing greater temperature variations.

[0013] Furthermore, relatively short electrical conductors appear to beneficially influence the quality of sterilizing and / or disinfecting gas mixtures. Although not fully understood, relatively short electrical conductors are believed to have beneficial effects on electromagnetic compatibility (EMC) and / or reduce system impedance, which may be advantageous. Reduced temperature variations contribute to a more stable generation of the desired sterilizing and / or disinfecting components in the gas mixture.

[0014] Optionally, the forced gas cooling system is configured to force a flow of cooling gas into the dielectric tubular portion in a direction substantially orthogonal to the longitudinal axis of the tubular portion (e.g., perpendicular to the longitudinal axis of the tubular portion). It has been found that such flow effectively provides a high-quality sterilizing and / or disinfecting gas mixture. Alternatively or additionally, the forced gas cooling system may be configured to force a flow of cooling gas into the dielectric tubular portion in a direction substantially parallel to the longitudinal axis of the tubular portion.

[0015] Optionally, the forced gas cooling system includes a temperature control system for controlling the temperature of the plasma and / or ionization chamber and / or tubular portion. The temperature control system may include temperature sensors and controllers.

[0016] Optionally, the forced gas cooling system includes a detector for detecting malfunctions in the cooling system and configured to shut down or reduce the power of the high-voltage power supply upon detection of a malfunction. Therefore, overheating of the plasma source can be avoided in the event of a cooling system malfunction.

[0017] Optionally, the length of the electrical conductor is less than 50 cm, preferably less than 30 cm, and more preferably less than 20 cm.

[0018] Optionally, the plasma source includes a first end cap that includes an inlet and closes the dielectric tubular portion at a first end. Optionally, the plasma source includes a second end cap that includes an outlet and closes the dielectric tubular portion at a second end opposite the first end. The end caps provide an efficient and mechanically simple way to provide the inlet and / or outlet to the dielectric tubular portion. Preferably, the first and / or second end caps are made of an electrically insulating material.

[0019] Optionally, the dielectric tube comprises walls of quartz or glass, such as borosilicate glass, for example... or

[0020] Optionally, the plasma source includes a housing, such as a metal housing. Optionally, the housing includes an ionization chamber, a high-voltage power supply, and at least a portion of a forced gas cooling system. Therefore, a plasma source that is easy to install and / or replace can be provided. Moreover, when the housing is a metal housing, EMC (Electromagnetic Compatibility) can be readily achieved.

[0021] The gas or gas mixture supplied to the inlet may be a humidified gas or gas mixture, such as humidified air. The gas or gas mixture may have a predetermined specific humidity, such as 2 to 25 grams of water vapor per kilogram of gas, or approximately 10 grams of water vapor per kilogram of gas. The gas or gas mixture may be humidified, for example, as described in pending patent application NL2025110, which is incorporated herein by reference.

[0022] According to a second aspect, a sterilization apparatus for sterilizing medical devices is provided, the sterilization apparatus comprising a plasma source as described above.

[0023] According to a third aspect, a method for generating a sterilizing gas mixture is provided. The method includes supplying a gas or gas mixture through a dielectric tubular portion having a first electrode located inside the dielectric tubular portion and a second electrode located outside the dielectric tubular portion. The method includes applying a high voltage difference between the first and second electrodes. The method includes cooling the dielectric tubular portion using a forced gas cooling system.

[0024] Optionally, the method includes supplying a high voltage to the first or second electrode through a relatively short electrical conductor.

[0025] It should be understood that any aspects, features, and choices described with respect to the plasma source also apply to sterilization apparatus and methods, and vice versa. It will also be clear that any one or more of the foregoing aspects, features, and choices can be combined.

[0026] Brief description of the attached figures

[0027] The embodiments of this application will now be described in detail with reference to the accompanying drawings, wherein:

[0028] Figure 1 A schematic diagram of the plasma source is shown;

[0029] Figure 2A A schematic diagram of the plasma source is shown;

[0030] Figure 2B A cross-sectional view of the forced gas cooling system is shown.

[0031] Figure 3 A schematic diagram of the sterilization apparatus is shown; and

[0032] Figure 4 A schematic diagram of the method is shown. Detailed Implementation

[0033] Figure 1 A schematic diagram of a plasma source 1 for generating a mixture of disinfecting and / or sterilizing gases is shown. The plasma source 1 includes an ionization chamber 2. The ionization chamber 2 is surrounded by a wall. A first wall is formed by a dielectric tubular portion 4. The dielectric tube may include or be a glass tube, for example made of quartz or glass, such as borosilicate glass, etc. or

[0034] In this example, the second wall is formed by a first end cap 6 that closes the dielectric tubular portion 4 at the first end. In this example, the third wall is formed by a second end cap 8 that closes the dielectric tubular portion 4 at the second end opposite the first end. Here, the end caps 6 and 8 are hermetically connected to the tubular portion 4. Here, a seal, such as an O-ring 10, is provided between the end caps 6 and 8 and the tubular portion 4.

[0035] The ionization chamber 2 includes an inlet 12 for supplying gas or a gas mixture into the chamber 2. Here, the inlet is located at the first end of the tubular portion 4. In this example, the inlet 12 forms part of a first end cap 6. The ionization chamber 2 includes an outlet 14 for discharging sterilizing gas from the chamber 2. Here, the outlet 14 is located at the second end of the tubular portion 4. In this example, the outlet 14 forms part of a second end cap 8.

[0036] The ionization chamber 2 includes a first electrode 16. The first electrode 16 is located inside the dielectric tubular portion 2. Here, the first electrode extends longitudinally within the tubular portion 2, specifically along the axis of the tubular portion 2. In this example, the first electrode 16 is elongated, for example, rod-shaped. Here, the first electrode 16 has a thicker rod diameter in the region where plasma is generated. In this example, the chamber 2 includes an electrical feedthrough 18 that forms an electrical connection from the outside of the chamber to the inside of the first electrode 16. Here, the feedthrough is located at the first end cap 6. Figure 1 For clarity, a gap is drawn between the feedthrough 18 and the first end cap 6. It should be understood that the feedthrough actually forms a hermetically sealed electrical connection from the outside of chamber 2 to the inside of chamber 2. In this example, both the first end cap 6 and the second end cap 8 include retainers for holding the first electrode in its position.

[0037] The ionization chamber 2 includes a second electrode 20. The second electrode 20 is located outside the dielectric tubular portion 4. The second electrode 20 may be formed on the outer surface of the tubular portion 4. The second electrode may be a separate component, such as a metal sheet located on the outer surface of the tubular portion 4, for example, in close contact with the outer surface of the tubular portion 4. In this example, the second electrode 20 forms a conductive layer coated on the outer surface of the tubular portion 4, such as a metal layer (plasma) deposited on the outer surface. Figure 1 For clarity, a gap is drawn between the second electrode 20 and the tubular portion 4. It should be understood that the second electrode 20 and the tubular portion are actually in contact with each other.

[0038] Plasma source 1 includes a high-voltage power supply 22. The high-voltage power supply 22 provides a high voltage difference between two output terminals 24 and 26. In this example, the first output terminal 24 is a high-voltage output terminal, and the second output terminal 26 is connected to or can be connected to electrical ground. The high voltage provided at the first output terminal 24 can be a positive high voltage or a negative high voltage. In this example, a first conductor 28 connects the first output terminal 24 to the first electrode 16. Here, a second conductor 30 connects the second output terminal 26 to the second electrode 20. It is understood that it is also possible for both the second output terminal 26 and the second electrode 20 to be connected to electrical ground. In this case, the dedicated second conductor 30 in the form of a lead can be omitted.

[0039] Plasma source 1 includes a forced gas cooling system 32. Figure 1 The forced gas cooling system 32 includes a fan 34. Figure 1 The forced gas cooling system 32 further includes a guide 36 for directing cooling gas to chamber 2. The guide 36 may include a funnel. Figure 2A An exemplary three-dimensional view of plasma source 1 is shown. Figure 2B A cross-sectional view of the forced gas cooling system 32 acting on the ionization chamber 2 is shown. Figure 2A and Figure 2B In the middle, the cross-section of the guide 36 gradually tapers towards the cavity 2. For example... Figure 2AAs shown, the guide can be formed of an elongated guide or funnel extending along the length of the tubular portion 4, for example, between end caps 6 and 8. As shown, the length of the elongated guide or funnel can be similar to or the same as the length of the tubular portion 4, for example, within ±20%. In this way, cooling can occur along substantially the entire length. For example, a forced gas cooling system includes an elongated funnel 36 having two sidewalls 36a, 36b that taper towards the dielectric tubular portion 4 and extend along the longitudinal axis. As shown, the funnel can be positioned between a fan 34 and the dielectric tubular portion 4. Multiple fans (not shown) can also be arranged along the wide end of the funnel, for example, side-by-side along the longitudinal axis. For example, the cooling system is configured to force a flow of cooling gas into the wide end of the funnel 36 via the fans, wherein the gas flow exits the narrow end of the funnel to impact one side of the tubular portion orthogonal to the longitudinal axis. For example, the wide end of funnel 36 is at least 1.2 (20%), 1.5 (50%), 2 (twice as wide), or more than the narrow end. Therefore, a relatively high gas flow can be easily established at or near the tubular portion 4. For example, the gas flow can be guided around the tube (e.g., in a split gas flow) from one side of the tubular portion to the opposite side of the tubular portion and carry away heat from the ionization chamber 2. Alternatively, or in addition to the gas flow shown, other or further gas flows can be established, for example, by guiding the gas flow away from the ionization chamber 2 by a fan. For example, one or more fans can be provided to force gas into and / or out of the housing 42.

[0040] exist Figure 2A In this example, the plasma source 1 includes a housing 42, such as a metal housing, for example, to shield electromagnetic radiation. In this example, the housing 42 includes an ionization chamber 2, a high-voltage power supply 22, and at least a portion of a forced gas cooling system 32. In this particular example, a fan 34 forms part of the housing 42. Figure 2A In the image, for clarity, housing 42 is shown as transparent.

[0041] The plasma source 1 described above can be used in method 200 for generating a mixture of disinfecting and / or sterilizing gases, see also [link to relevant documentation]. Figure 4 A gas or gas mixture, such as air, for example air with a predetermined specific humidity, is supplied 202 into ionization chamber 2 via inlet 12. In ionization chamber 2, plasma 204 is generated by applying a high voltage difference between first electrode 16 and second electrode 20. Subsequently, the gas or gas mixture flowing through ionization chamber 2 is at least partially ionized to form a sterilizing and / or disinfecting gas mixture. The sterilizing and / or disinfecting gas mixture flows out of ionization chamber 208 via outlet 14.

[0042] During ionization, i.e., during plasma generation, the ionization chamber 206 is cooled using a forced gas cooling system 32. In this example, a fan 34 generates an airflow directed toward the ionization chamber 2. Here, the airflow is directed toward the ionization chamber via a guide 36, such as a guide tubular portion 4. Here, the airflow is directed in a direction substantially orthogonal to the longitudinal axis of the tubular portion 4, which is perpendicular to the longitudinal axis of the tubular portion 4. In principle, the forced gas cooling system can also be configured to force a cooling gas flow toward the dielectric tubular portion in a direction substantially parallel to the longitudinal axis of the tubular portion. However, by blowing gas orthogonally to the tubular portion, heat can be dissipated more rapidly and / or more uniformly. For example, positively alternating heated gas can leave the vicinity of the tubular portion more quickly than heated gas flowing along the length of the tube. For example, positively alternating gas can have a substantially uniform temperature along the length of the tube compared to heated gas when the gas flows along the length of the tube. By using forced gas cooling, the temperature of the ionization chamber and the gas or gas mixture therein can be kept substantially constant. It has been found that this has a beneficial effect on the quality of disinfection and / or sterilization gas mixtures.

[0043] It has also been found that providing a high-voltage first conductor 28 with a relatively short length appears to beneficially affect the quality of the disinfecting and / or sterilizing gas mixture. Although not fully understood, it is believed that the relatively short conductor reduces variations in the supply voltage, which in turn reduces temperature variations. Reduced temperature variations can contribute to a more stable generation of the desired disinfecting and / or sterilizing components in the gas mixture. Here, the relatively short length is 50 cm or less, preferably 30 cm or less, more preferably 20 cm or less. It is understood that the first output terminal 24 can be directly connected to the first electrode 16. Therefore, the length of the first conductor 28 is zero. The second output terminal 26 can also be directly connected to the second electrode 20. Therefore, the length of the second conductor 30 is zero.

[0044] While generating plasma, the forced gas cooling system 32 of the cooling chamber 2 (e.g., the exterior of the cooling tubular portion 4) can induce a temperature gradient in the ionization chamber 2.

[0045] The forced gas cooling system 32 includes a temperature control system 37 for controlling the temperature of the plasma and / or ionization chamber 2 and / or tubular portion 4. The temperature control system 37 may include a temperature sensor 39. The sensor 39 may be mounted on the inner or outer surface of the tubular portion (e.g., inside the ionization chamber 2), or near the tubular portion 4 outside the ionization chamber 2. Alternatively or additionally, the temperature sensor 39 may be placed in the gas flow output from the ionization chamber 2. Controlling the plasma temperature, for example, by controlling the temperature of the ionization chamber 2 or the tubular portion 4, can provide two advantages. A controlled plasma temperature is beneficial for influencing the temperature stability of the plasma source. Furthermore, by adjusting the setpoint of the controlled plasma temperature, the quality of the sterilizing and / or disinfecting gas mixture (e.g., a composition of sterilizing and / or disinfecting gas mixtures) can be selected.

[0046] The forced gas cooling system 32 may include a detection system 38 for detecting cooling system malfunctions. The detection system 38 may be configured to shut down or reduce the power of the high-voltage power supply 22 when a malfunction of the cooling system 32 is detected. Therefore, overheating of the plasma source can be avoided in the event of a malfunction of the cooling system 32. The detection system may include a detector 40 for detecting malfunctions of the cooling system 32. The detector 40 may include a gas flow sensor for monitoring the flow of cooling gas. The detector 40 may include a current sensor for detecting the motor current of the fan 34. The detector 40 may include a temperature sensor, such as sensor 39, for sensing the temperature of the plasma source 1, such as the temperature of the chamber 2, the tubular portion 4, and / or the housing 42. The detector 40 may be, for example, a thermal switch.

[0047] Figure 3 An example of a sterilization apparatus 100 for sterilizing a medical device 102 (e.g., a dental instrument) is shown. The sterilization apparatus 100 includes, as... Figure 1 And the plasma source 1 shown in Figure 2. The sterilization apparatus 100 includes a sterilization chamber 104. A sterilizing and / or disinfecting gas mixture is supplied from the plasma source 1 into the sterilization chamber 104, toward the instruments 102 housed in the sterilization chamber 104.

[0048] The invention is described herein with reference to specific examples of embodiments thereof. However, it will be apparent that various modifications and changes can be made thereto without departing from the spirit of the invention. For clarity and brevity, descriptive features that are part of the same or separate embodiments are described herein; however, alternative embodiments having combinations of all or some of the features described in these separate embodiments are also contemplated.

[0049] exist Figure 1In the example, the first electrode is connected to a high voltage, while the second electrode is connected to electrical ground. It should be understood that the first electrode can also be connected to electrical ground, and the second electrode can also be connected to a high voltage. Both the first and second electrodes can be connected to a high voltage, for example, one connected to a positive high voltage and the other connected to a negative high voltage. Preferably, the conductor providing the high voltage to the first or second electrode has a relatively short length of 50 cm or less, preferably 30 cm or less, more preferably 20 cm or less.

[0050] Preferably, the high-voltage power supply as described herein is configured to generate high voltage and / or current within a relatively short time interval, such as less than 50 milliseconds, preferably less than 20 milliseconds, after startup (e.g., starting at zero volts / amperes). More preferably, after startup, the voltage and / or current ramp up with an initial overshoot (e.g., at least 10%) exceeding the rated operating voltage to initiate plasma generation. For example, the high-voltage power supply is powered by a power source suitable for allowing such rapid startup. The inventors have found that these settings can result in more stable and / or reliable plasma.

[0051] For the purposes of clarity and brevity, descriptive features that are part of the same or separate implementations are described herein; however, it should be understood that the scope of the invention may include implementations having a combination of all or some of the features described.

[0052] In the claims, any reference numerals enclosed in parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of other features or steps not listed in the claims. Furthermore, the words "a" and "an" should not be construed as limited to "only one / a," but are used to indicate "at least one / a," and do not exclude multiple / a. The fact that certain measures are stated in dissimilar claims does not mean that a combination of these measures cannot be used as an advantage.

Claims

1. A plasma source for generating a mixture of disinfecting and / or sterilizing gases, comprising: - An ionization chamber, said ionization chamber having: - Dielectric tubular portion, - Inlet, which is used to supply gas or gas mixture into the dielectric tubular portion. - An outlet for discharging the disinfecting and / or sterilizing gas mixture from the dielectric tubular portion. - The first electrode, located inside the dielectric tubular portion, and - The second electrode is located outside the dielectric tubular portion; - A high-voltage power supply having a high-voltage output terminal, wherein an electrical conductor connects the output terminal to either the first electrode or the second electrode; and - A forced gas cooling system for cooling the ionization chamber. The plasma source further includes a first end cap and a second end cap, the first end cap including the inlet and closing the dielectric tubular portion at a first end, the second end cap including the outlet and closing the dielectric tubular portion at a second end opposite to the first end, and wherein the first end cap and / or the second end cap are made of an electrically insulating material; wherein the forced gas cooling system is configured to force a cooling gas flow onto the dielectric tubular portion in a direction substantially orthogonal to the longitudinal axis of the tubular portion; and The forced gas cooling system includes an elongated funnel with two sidewalls that taper towards the dielectric tubular portion and extend along the longitudinal axis. The funnel is disposed between at least one fan and the dielectric tubular portion and is configured to force a flow of cooling gas into the funnel via the fan, toward a narrow end where the two sidewalls converge. The narrow end has an elongated outlet opening adjacent to the dielectric tubular portion and extending along the longitudinal axis. The outlet opening is positioned facing the dielectric tubular portion and is configured to force the flow of cooling gas exiting the opening to flow in a direction substantially orthogonal to the longitudinal axis to one side of the tubular portion.

2. The plasma source of claim 1, wherein the forced gas cooling system includes a detector for detecting a fault in the cooling system and is configured to shut down the high-voltage power supply or reduce the power of the high-voltage power supply when a fault is detected.

3. The plasma source of claim 1, wherein the length of the electrical conductor is less than 50 cm.

4. The plasma source of claim 1, wherein the length of the electrical conductor is less than 30 cm.

5. The plasma source of claim 1, wherein the length of the electrical conductor is less than 20 cm.

6. The plasma source of claim 1, wherein the second electrode is a conductive layer deposited on the outer surface of the dielectric tubular portion.

7. The plasma source of claim 1, wherein the second electrode is connected to an electrical ground.

8. The plasma source of claim 1, wherein the dielectric tubular portion comprises a wall of quartz or glass.

9. The plasma source of claim 8, wherein the glass is borosilicate glass.

10. The plasma source of any one of claims 1 to 9, comprising a housing, wherein the housing includes at least a portion of the ionization chamber, the high-voltage power supply, and the forced gas cooling system.

11. The plasma source of any one of claims 1 to 9, wherein the high-voltage power supply is configured to generate a high voltage and / or current within a relatively short time interval of less than 50 milliseconds after startup, wherein the high-voltage power supply is configured to ramp up the high voltage and / or current at startup with an initial overshoot to initiate plasma generation, and then reduce it to a rated operating value for maintaining the plasma generation, wherein the initial overshoot is at least 10% higher than the rated operating value.

12. The plasma source of claim 11, wherein the high-voltage power supply is configured to generate high voltage and / or current within a relatively short time interval of less than 20 milliseconds after startup.

13. A sterilization apparatus for sterilizing medical devices, comprising a plasma source according to any one of claims 1 to 12.

14. A method for generating a mixture of disinfecting and / or sterilizing gases, comprising: - Gas or a gas mixture is supplied through an inlet formed by a first end cap located at a first end of a dielectric tubular portion, the dielectric tubular portion having a first electrode located inside the dielectric tubular portion and a second electrode located outside the dielectric tubular portion; - Apply a high voltage difference between the first electrode and the second electrode; - The dielectric tubular portion is cooled using a forced gas cooling system, wherein the forced gas cooling system includes an elongated funnel having two sidewalls that taper toward the dielectric tubular portion and extend along the longitudinal axis of the dielectric tubular portion, wherein at least one fan blows a stream of cooling gas into the wide end of the funnel such that a concentrated and / or accelerated stream of cooling gas exits the narrow end of the funnel to impinge on one side of the tubular portion in a direction orthogonal to the longitudinal axis, thereafter the impinging gas flows around the tubular portion to the opposite side of the tubular portion, and is thereafter orthogonally guided away from the tubular portion; and - A mixture of sterilizing and / or disinfecting gases is discharged through an outlet formed by a second end cap located at the second end of the dielectric tubular portion, wherein the first end cap and / or the second end cap are made of an electrically insulating material.

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