EP0800201A2 - Long-life excimer radiator, processes for manufacturing and for increasing the life of such a radiator and device for implementing said processes - Google Patents

Abstract

In an excimer emitter with a halogen-containing gas-filled discharge space, the halogen content of the discharge space (16) is ≥ 1 x 10<-10>, preferably 1 x 10<-10>-1 x 10<-5>) mol/cm<3> per cm<2> of its interior surface and is also adjusted in accordance with the maximum power density (in W/cm of emitter length) of the emitter (11) to a value of 1 x 10<-7>-1 x 10<-5> mol/cm<3> per unit power density. Also claimed are: (i) the production of a long life excimer emitter as above, in which the interior surfaces of the discharge space (16) are exposed to a halogen-containing passivating gas, preferably chlorine, prior to gas filling; (ii) a process for extending the life of an excimer emitter, having a halogen-containing gas-filled discharge space, by exposing the discharge space (16) to IR radiation or by releasing halogen from a halogen reservoir (17) located in the discharge space (16); and (iii) an apparatus for carrying out the above processes (i) and (ii).

Description

The invention relates to an excimer radiator with a discharge space which contains a halogen-containing filler gas which forms excimers under discharge conditions. Furthermore, the invention relates to a method for producing a long-life excimer radiator and a method for extending the life of such an excimer radiator as well as a device for carrying out the last-mentioned method

Excimer emitters are used to generate high-energy UV radiation. Excimer radiation is also known as silent electrical discharge. This is generated in a discharge space delimited by dielectrics, in which the filling gas forming the excimers is contained.

An excimer radiator of the type specified is known from EP-A1 0 547 366. In the excimer radiator described there, various noble gases, for example argon, krypton or xenon or noble gas mixtures, are proposed as filler gases, depending on the desired spectral composition of the radiation, which contain, for example, chlorine or a chlorine-containing compound, from which one or more chlorine atoms are split off in the discharge will.

No information is given in EP-A1 0 547 366 about the chlorine concentration to be set. In the case of the commercially available excimer lamps, the chlorine content, based on the chlorine content in the corresponding excimer lasers, is set to a mixing ratio of chlorine to an inert gas or to an inert gas mixture of 1/1000. Such an excimer emitter is part of Mr. Volker Shorpp's doctoral thesis, for example the title "The Dielectric Impaired Noble Gas Halogen Excimer Discharge: A Novel UV Radiation Source", University of Karlsruhe, 1991.

An excimer radiator designed as a planar flat radiator is known from EP-A2 0 521 553. The discharge space contains a halogen-containing rare gas filling, the partial pressure of the halogen being between 0.05% and 5% of the partial pressure of the rare gas. The well-known excimer radiator is characterized by a high irradiance.

With the excimer lamps known to date, the maximum adjustable UV irradiance is reduced within the first 300 operating hours. The drop in UV irradiance is typically greater than 50% of the initial illuminance.

An attempt to extend the life of such a radiator is explained in EP-A1 607 960. An excimer radiator is described therein which has a discharge space which is filled with a suitable filling gas and is sealed in a gastight manner. For the purpose of extending the life of the radiator, it is proposed to remove gaseous contaminants from the filling gas and to provide a "getter" for this purpose, which can be arranged inside the discharge space or in connection with it. However, it has been shown that the removal of fill gas impurities is not sufficient for a significant increase in the service life.

The present invention is therefore based on the object of specifying an excimer radiator with a long service life and of providing a method for producing such an excimer radiator. Furthermore, the invention is based on the object of specifying a method for increasing the service life of excimer radiators and a device suitable therefor.

With regard to the excimer radiator, the object is achieved on the basis of the excimer radiator mentioned at the outset in that the halogen content of the discharge space (16) per cm ^{2 of} its inner surface is at least 1 × 10 ^-10 mol / cm ³ and at the same time as a function of the maximum power density of the radiator, expressed in the unit "watts per cm of radiator length" is set to a value in the range from 1 x 10 ^-7 mol / cm ³ to 1 x 10 ^-5 mol / cm ³ per unit of power density.

It was found that it is not primarily impurities in the filling gas that are responsible for the decrease in the UV irradiance in the known excimer lamps, but rather a depletion of the filling gas in halogens. In the following "halogen" fluorine, chlorine, bromine and iodine and mixtures of these gases; “noble gas” means helium, neon, argon, krypton and xenon and mixtures of these gases. Contains the fill gas Compounds which release halogens under discharge conditions are relevant to the halogen concentrations actually released under discharge conditions. It has been shown that the release of the halogens essentially depends on the power density with which the emitter is operated.

The halogen loss can be based on a reaction of the halogen with the inner surfaces of the discharge space. The boundary walls of the discharge space can consist, for example, of quartz glass or of a ceramic. The surface reaction of the halogen can be avoided by a suitable modification of the inner surfaces delimiting the discharge space. However, such measures are complex and expensive and, moreover, the modifications produced are often not sufficiently resistant to discharge. For example, applied protective layers can peel off.

It has been found that an extension of the service life can be achieved by an initially increased halogen concentration in the filling gas. This can be attributed to the fact that there is no constant consumption of halogen on the inner surface of the discharge space, but rather a saturation of the surface reaction can be observed with increasing supply of halogen in the filling gas. The halogen content in the filling gas above which this saturation can be observed and at which there is also a sufficient halogen concentration within the discharge space for the excimer discharge is referred to below as the saturation concentration. The saturation concentration depends on the operating temperature of the excimer radiator, but in particular on its power and on the size of the inner surface of the discharge space. It has been found that the saturation concentration, based on the inner surface of the discharge space, is at a halogen content of at least 1 × 10 ^-10 mol / cm ³ per cm ^{2 of} the inner surface. This halogen content can be measured in the filling gas before surface reactions with the halogen have taken place, for example before the emitter is started up. In the event that the inner surfaces of the discharge space have been loaded with the halogen beforehand or after the emitter has been started up, the halogen content in the discharge space can be determined if all halogen bound to or in the inner surface of the discharge space is added to the halogen content of the filling gas. The halogen content bound to or in the inner surface of the discharge space can be determined, for example, by releasing the halogen into the discharge space by means of a suitable temperature treatment. This halogen content can also be determined chemically or spectroscopically. It should be noted, however, that such halogen, which delimits the discharge space inside the material Walls may also be present, is not taken into account. For example, synthetic quartz glass often contains a certain amount of chlorine due to the manufacturing process.

If the specified saturation concentration of halogens in the discharge space is permanently set, a decrease in the irradiance over time is avoided in whole or in part. A halogen concentration above the actually sufficient saturation concentration does not have a detrimental effect on the lifetime behavior. However, it affects the radiation characteristics of the radiator and reduces its maximum power density. The halogen concentration to be set continues to depend on the maximum power density of the radiator. On the other hand, it is therefore necessary to observe the further dimensioning rule that the halogen content in the discharge space, depending on the maximum power density of the emitter, expressed in the unit "watt per cm emitter length", to a value in the range from 1 x 10 ^-7 mol / cm ³ to 1 x 10 ^-5 mol / cm ³ per unit of power density is set.

The relationship between the power density and the suitable halogen content of the discharge space has been shown to be approximately linear up to a power density of approximately 200 W / cm lamp length. It can be assumed that this relationship is also valid at even higher power densities, for example at power densities around 400 W / cm. The length of the spotlight is only the length of the spotlight that is actually illuminated.

Based on the teaching of the patent claim, it is no problem for the person skilled in the art to adjust the halogen content to the specific radiator geometries and outputs.

In the case of the usual excimer emitters, the stated saturation concentration corresponds approximately to a mixture ratio of halogen: noble gas of 1:50 to 1: 500. These mixture ratios are only given as a guide for easier orientation. It is expressly pointed out in this connection that it is not the mixing ratio, but the absolute halogen content, based on the size of the inner surface and the volume of the discharge space, and at the same time based on the maximum power density of the excimer radiator, that are decisive for the excimer radiator according to the invention. Any buffer gases in the discharge space, which can also be noble gases, are not taken into account.

An excimer emitter in which the halogen content of the discharge space per cm ^{2 of} its inner surface is in the range from 1 × 10 ^-10 mol / cm ³ to 1 × 10 ^-8 mol / cm ³ has proven particularly useful. The specified upper limit results from the increasing halogen content decreasing efficiency of the radiator. Halogen has a high electronegativity and usually has a lower probability of excitation compared to the noble gas. It therefore captures a relatively large number of electrons; the heater is difficult to ignite if the chlorine content is high. On the other hand, the filament density and consequently the halogen content in its atomic form increases with increasing power density of the excimer lamp. However, atomic halogen accumulates particularly easily on the boundary walls of the discharge space. The specified upper limit of the halogen concentration is therefore particularly relevant for excimer lamps with a high power density around 100 W per cm of lamp length, while with excimer lamps with a lower power density - without prejudice to the above-mentioned dimensioning rule with regard to the power density - this upper limit can be exceeded.

An excimer radiator has a particularly long service life, in which the filling gas contains chlorine or a compound which releases chlorine under discharge conditions. A suitable chlorine-containing filling gas contains, for example, HCl with 2% Cl ₂ and an inert gas, such as krypton, xenon or argon.

An excimer emitter in which a halogen-containing reservoir is arranged in the discharge space has proven to be particularly advantageous, the concentration of the halogen in the reservoir being higher than that in the filling gas. The halogen in the halogen reservoir is separated from the filling gas in the discharge space. If the halogen content falls below a predetermined lower limit, the reservoir can be opened automatically or manually, the halogen contained therein being released into the discharge space. The halogen content of the reservoir is dimensioned such that the concentration of the halogen in the discharge space is increased by the release; for example, the target concentration of the halogen in the discharge space can be achieved by the release. A suitable halogen content of the reservoir thus results simply from the difference between the concentration at the lower limit and the target concentration and the volume of the discharge space. The reservoir has a relatively small volume compared to the volume of the discharge space. The halogen concentration in the reservoir is therefore relatively high. The reservoir can be designed, for example, in the form of a chamber made of quartz glass or a ceramic, which is broken when the said lower concentration limit is reached. The lower concentration limit can be determined on the basis of intensity measurements of the excimer radiation.

With regard to the method for producing a long-life excimer radiator, the above-mentioned object is based on the method mentioned at the outset solved in that the inner surfaces of the discharge space are charged with a halogen-containing passivation gas before filling the filling gas.

It has been found that a higher proportion of halogen in the filling gas of the discharge space is not necessary if the inner surfaces of the discharge space have been treated with a halogen before the filling gas has been filled in. This pretreatment with halogen "passivates" the inner surfaces of the discharge space, so to speak. Passivation causes the inner surfaces to be saturated with halogen, which means that the subsequent consumption of halogen from the filling gas due to absorption in, adsorption on or chemical reaction with the boundary walls of the discharge space is reduced or even prevented during later operation of the excimer lamp.

This passivation is a relatively simple modification of the inner surface of the discharge space. It can be done, for example, in a simple manner by flushing the discharge space with the halogen.

The method according to the invention has proven to be particularly effective with regard to the extension of the service life in excimer lamps in which chlorine or a compound which releases chlorine under discharge conditions is used if chlorine is used for the passivation.

The halogen content of the passivation gas per cm ^{2 of} the inner surface of the discharge space is advantageously at least 1 × 10 ^-10 mol / cm ³ , with the proviso that it is chosen to be at least as large as the halogen content in the filling gas. The term "halogen content" is understood to mean the concentration of the halogen based on the volume of the discharge space. The passivation can take place on walls of the discharge space made of quartz glass at an elevated temperature up to 1000 ° C; with ceramic walls even at higher temperatures.

With regard to the method for extending the lifespan of an excimer radiator, the above-mentioned object is achieved according to the invention in that the discharge space is exposed to infrared radiation or that halogen is released from a halogen reservoir arranged in the discharge space.

In the first alternative of the method, the walls delimiting the discharge space are heated by the infrared radiation. These are usually quartz glass walls. It was shown that the warming can reverse a previously depleted halogens in the filling gas.

Originally, it was assumed that the halogen is firmly absorbed on the quartz glass or forms a stable chemical bond with the silicon of the quartz glass.

By applying infrared radiation to the excimer radiator either during operation or in a resting phase when the excimer radiator is switched off, the halogen content of the filling gas can be regenerated. In this respect, the loss of halogen has proven to be reversible. Surprisingly, the reversibility of the halogen loss is accompanied by an extension of the life of the excimer lamp. Due to the temporary loss of halogen within the discharge space and operation with a low halogen content, there is no irreversible damage to the excimer lamp.

For exposure to infrared radiation, the excimer radiator can be placed in an oven, for example, or it is exposed to the radiation emitted by an infrared radiator.

In the second alternative of the method according to the invention, halogen is released from a halogen reservoir arranged in the discharge space. The concentration of the halogen in the reservoir is set higher than that in the filling gas. A halogen loss in the discharge space can be compensated for by the additional halogen from the reservoir. If the halogen content falls below a predetermined lower limit, the reservoir can be opened automatically or manually, the halogen contained therein being released into the discharge space. With regard to the formation of the halogen reservoir, its halogen content and the determination of the lower concentration limit, reference is made to the above explanations.

A method has proven to be particularly advantageous in which the discharge space is heated to a temperature in the range from 400 ° C. to 1000 ° C. by means of infrared rays. This temperature range applies to a discharge space with boundary walls made of quartz glass. If the boundary walls consist of a ceramic, such as Al ₂ O ₃ , temperatures above 1000 ° C are more favorable. Such a procedure has proven to be particularly effective in the case of chlorine-containing filling gas.

With regard to the device for carrying out the method for extending the life of an excimer radiator, the object stated above is achieved according to the invention in that at least one infrared radiator is provided, which is arranged adjacent to the excimer radiator, in such a way that the infrared radiation emanating from the infrared radiator heats the discharge space.

By arranging the excimer radiator and the infrared radiator next to one another, the above-described method for extending the excimer radiator can be carried out in a simple manner at any time. To do this, only the infrared heater has to be switched on. The infrared radiation is directed towards the discharge space and heats its boundary walls. This releases the halogen absorbed or adsorbed on it.

In principle, every oven is also suitable as an infrared heater. The infrared radiator is advantageously provided with a reflector, which directs the infrared radiation onto the discharge space and thereby prevents the infrared radiation from being emitted undesirably in other directions.

In a preferred embodiment of the device, the length of the infrared radiator or the total length of all infrared radiators corresponds approximately to the length of the discharge space. This effectively releases the halogen over the entire length of the discharge space. The infrared radiator advantageously runs or the infrared radiators run parallel to the discharge space of the excimer radiator.

A device in which the at least one infrared radiator and the excimer radiator are electrically connected to one another in such a way that the infrared radiator is switched on after a definable time interval before or after the excimer radiator is switched on has proven particularly useful. This embodiment of the device has the advantage that the halogen is released in a reproducible manner from the inner surfaces delimiting the discharge space. Excimer emitters and infrared emitters can be switched on at the same time, so the above-mentioned time interval can also be 0.

Figur 1:

ein Zeitstanddiagramm bei verschiedenen XeCl-Excimerstrahlern,

Figur 2:

ein Zeitstanddiagramm bei KrCl-Excimerstrahlern mit hoher Leistung,

Figur 3:

ein Zeitstanddiagramm bei KrCl-Excimerstrahlern mit niedriger Leistung und

Figur 4:

einen Ausschnitt aus einem Excimerstrahler mit einem Halogenreservoir im Entladungsraum in einer Längsansicht in schematischer Darstellung

The invention is explained in more detail below on the basis of exemplary embodiments and on the basis of the patent drawing. In the drawing show in detail

Figure 1:

a timing diagram for different XeCl excimer emitters,

Figure 2:

a timing diagram for KrCl excimer emitters with high power,

Figure 3:

a timing diagram for KrCl excimer emitters with low power and

Figure 4:

a section of an excimer radiator with a halogen reservoir in the discharge space in a longitudinal view in a schematic representation

In the diagrams according to FIGS. 1 to 3, the operating hours are plotted on the X-axis and a relative irradiance on the Y-axis.

Figure 1 shows the life behavior of XeCl module radiators. These generate a power density of 25 W / cm lamp length. The filling pressure of the filling gas in the discharge space is 750 mbar. Argon as a buffer gas contributes about 300 mbar to this internal pressure. The discharge space in these emitters is formed by the space between two quartz glass tubes which run coaxially to one another. The outer diameter of the discharge space is 27 mm, the inner diameter is 16 mm and the length is 343 mm.

The curve labeled with the reference number 1 represents the service life behavior of a previously available XeCl module radiator. In this, the mixing ratio of xenon to chlorine is about 1000: 1. The absolute chlorine content in the discharge space is below 1 x 10 ^-10 mol / cm ³ per cm ^{2 of} the inner surface of the discharge space; more precisely at about 3 x 10 ^-11 mol / cm ³ : the inside surface of the discharge space is about 470 cm ² . The concentration information relates to the volume of the discharge space.

From the course of curve 1 it can be seen that immediately with the use of the radiators a rapid decrease in the relative irradiance of the XeCl module radiator sets in, which after approx. 300 operating hours runs down to a final value which is in the range of 20% of the original irradiance . From this relatively low level of irradiance, a further deterioration in the irradiance can no longer be observed in the known excimer radiators. The decrease in the irradiance can be attributed, among other things, to a depletion of chlorine in the filling gas.

The curve shape designated by the reference number 2 represents the service life behavior in a XeCl module radiator in which the chlorine content of the discharge space is quintupled compared to the known excimer radiator described above. The mixing ratio of xenon to chlorine is therefore about 200: 1. From the above information, the chlorine content is 1.5 x 10 ^-10 mol / cm ³ and cm ^{2 of} the inner surface of the discharge space. The power density is approximately 30 watts per cm of illuminated spotlight length. Otherwise, the XeCl module radiators considered are identical. During the operation of the XeCl module radiator according to the invention, chlorine accumulates on the inner walls of the discharge space; The chlorine content in the filling gas therefore gradually decreases and can drop below the value of, for example, 5 × 10 ^-11 mol / cm ³ and cm ^{2 of} the inner surface.

The service life behavior of the XeCl module radiator according to the invention is characterized by only a slight and, in particular, very slow decrease in the UVB irradiance over time. After approx. 1000 hours of operation, the relative UVB irradiance only decreased by approx. 20%. However, curve 2 does not yet show whether the irradiance amounts to an end value.

A similar result of the service life behavior results from the creep diagrams of KrCl module radiators shown in FIG . These generate a power density of 25 W / cm lamp length. The filling pressure of the filling gas in the discharge space is 350 mbar. The discharge space in these emitters is also formed by the space between two quartz glass tubes which run coaxially to one another. The outer diameter of the discharge space is 27 mm, the inner diameter is 16 mm and the length is 343 mm.

Here, reference number 3 is assigned to a creep curve, as is usually measured in a KrCl module radiator according to the prior art. The mixing ratio of krypton to chlorine is approximately 1000: 1. The absolute chlorine content in this radiator is the same as in the known XeCl module radiator described above. Here, too, a relatively strong drop in UVC radiation intensity can be observed immediately after use of the lamp, which after approx. 300 to 400 operating hours results in a low final value, which is below 10% of the original radiation intensity.

Curves 4 and 5 are assigned to KrCl module radiators, which differ from one another only in the mixing ratio of the filling gas. These generate a power density of 25 W / cm lamp length. A buffer gas is not included. With the excimer emitter according to curve 4, the initial krypton: chlorine mixing ratio is 100: 1, with the creep curve 5 50: 1. The latter mixing ratio corresponds to a chlorine content of approx. 6 x 10 ^-10 mol / cm ³ per cm ^{2 of} the inner surface of the discharge space. The inside surface of the discharge space is approximately 470 cm ² .

The course of all creep curves 4 and 5 is characterized by an initial slight increase in the UVC irradiance, which then, after a few hours of operation, results in a high and constant final value, which is dependent on the chlorine concentration. A decrease in the irradiance is not observed in the KrCl module radiator according to the invention even after 1000 hours of operation.

The life cycle behavior of KrCl excimer emitters with a relatively low power of 30 W is shown in the creep curves according to FIG . The illuminated spotlight length is 10 centimeters. It has been shown that the chlorine loss increases with increasing power density. This is based on the effect already mentioned, according to which the atomic chlorine content increases with increasing filament density, which in turn reacts on the inner walls of the discharge space and is thus removed from the filling gas.

The creep curve labeled with the reference numeral 6 in turn shows the typical service life curve for commercially available excimer lamps, whereby after an initially strong decrease in UVC irradiance after 350 operating hours, an end value of the irradiance is reached at a low level.

In the KrCl excimer emitter according to the invention according to FIG. 3 , the initial mixing ratio of chlorine: krypton in the filling gas is 1: 1000. The particularly good lifetime behavior of the emitter shown in FIG. 3 is the result of passivation of the inner surface of the discharge space before the filling gas is filled .

To passivate the inner surface of the discharge space, it was evacuated, then filled with chlorine at room temperature, which was then pumped out again after about 3 seconds. The discharge space was then filled with the filling gas and sealed gas-tight

Due to the passivation of the inner surfaces of the discharge space, the KrCl excimer emitter according to the invention shows only a slight decrease in the UVC irradiance during the test period of approximately 2000 hours.

In a further exemplary embodiment, the KrCl excimer radiator, the service life behavior of which is represented by the creep curve 3 and in which the mixing ratio of krypton: chlorine = 1000: 1, was subjected to a heat treatment at a temperature of 750 ° C. for a period of one hour. As a result, an increase in the relative UVC irradiance of the excimer lamp from less than 10% of the initial value to 80% of this value was observed.

Overall, reference number 11 is assigned to the excimer radiator shown schematically in FIG . The excimer radiator 11 consists of an outer quartz glass tube 12, which is covered on its outer surface with a metallic mesh 13, which forms the outer electrode of the excimer radiator 11 and an inner quartz glass tube 14, which is arranged coaxially with the outer quartz glass tube 12 and on the inner wall of which Metallic spiral 15 is present, which forms the inner electrode of the excimer lamp 11. The annular gap between the outer quartz glass tube 12 and the inner quartz glass tube 14 corresponds to the discharge space 16 of the excimer radiator 11. The volume of the discharge space 16 is approximately 470 cm ³ . The power density of the spotlight is 30 watts per cm of the illuminated spot length.

The filling gas in the discharge space 16 consists of KrCl in a mixing ratio of krypton: chlorine = 1000: 1.

A quartz glass capsule 17 filled with chlorine is arranged in the discharge space 16. The wall of the capsule 17 is scored and in this way provided with a predetermined breaking point 18. The chlorine content of the capsule 17 is set such that after breaking the capsule 17, the chlorine content in the discharge space 16 is increased, namely by 1 × 10 ^-11 mol / cm ³ and per cm ^{2 of} the inner surface of the discharge space 16.

A metal part 19 is embedded in the wall of the capsule 17 and shielded from the discharge space 16. The metal part 19 together with the capsule 17 is held in an upper position by means of a magnet 20. If the capsule 17 is dropped from this position by removing or switching off the magnet 20, it breaks and the chlorine contained therein escapes into the discharge space 16. In this way, the chlorine content in the discharge space 16 can be regenerated. To determine the optimum time for regeneration, the intensity of a characteristic emission wavelength of the excimer radiator 11 is measured by means of a UV sensor. If the intensity falls below a lower limit, this is indicated optically and the magnet 20 is then removed. In an alternative embodiment, in which the magnet 20 is designed as an electromagnet, the magnet 20 is automatically switched off when the intensity falls below a lower limit and the chlorine is thereby released from the capsule 17 into the discharge space 16.

Claims (12)

Excimer radiator with a discharge space which contains a halogen-containing filling gas which forms excimers under discharge conditions, characterized in that the halogen content of the discharge space (16) per cm ^{2 of} its inner surface is at least 1 × 10 ^-10 mol / cm ³ and at the same time as a function of the maximum Power density of the emitter (11), expressed in the unit "watt per cm emitter length" is set to a value in the range from 1 x 10 ^-7 mol / cm ³ to 1 x 10 ^-5 mol / cm ³ per unit of the power density. Excimer radiator according to Claim 1, characterized in that the halogen content of the discharge space (16) per cm ^{2 of} its inner surface is in the range from 1 x 10 ^-10 mol / cm ³ to 1 x 10 ^-8 mol / cm ³ . Excimer radiator according to Claim 1 or 2, characterized in that the filling gas contains chlorine or a compound which releases chlorine under discharge conditions. Excimer radiator according to one of the preceding claims, characterized in that a reservoir (17) containing the halogen is arranged in the discharge space (16), the concentration of the halogen in the reservoir (17) being higher than that in the filling gas. Method for producing a long-life excimer radiator according to one of the preceding claims, characterized in that the inner surfaces of the Discharge chamber (16) are charged with a halogen-containing passivation gas before filling the filling gas. A process for producing a long-life excimer lamp according to claim 5, characterized in that chlorine is used for passivation in excimer lamps in which chlorine or a compound which releases chlorine under discharge conditions is used. Method for extending the service life of an excimer radiator which has a discharge space which contains a halogen-containing filling gas which forms excimers under discharge conditions, characterized in that the discharge space (16) is exposed to infrared rays or that halogen from a halogen arranged in the discharge space (16) Reservoir (17) is released. Method for extending the life of an excimer radiator according to claim 7, characterized in that the discharge space is heated to a temperature in the range from 400 ° C to 1000 ° C by means of infrared rays. A method according to claim 7, characterized in that a glass container (17) is used as the halogen reservoir, which is broken to release the halogen. Device for carrying out the method according to one of claims 7 or 8, characterized in that at least one infrared radiator is provided, which is arranged adjacent to the excimer radiator, such that the infrared radiation emanating from the infrared radiator heats the discharge space. Apparatus according to claim 10, characterized in that the length of the infrared radiator or the total length of all infrared radiators correspond approximately to the length of the discharge space. Device according to one of claims 10 or 11, characterized in that the at least one infrared radiator and the excimer radiator are electrically connected to one another in such a way that the infrared radiator is switched on after a definable time interval before or after the excimer radiator is switched on.

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