JP2014531712A - Crucible for translucent waveguide plasma light source - Google Patents

Abstract

The present application includes a waveguide body having a bore and made of a translucent material, and a tube made of a translucent material provided in the bore and in close contact with the translucent material of the waveguide body. It is related with the intermediate product of crucible manufacture characterized by this. The present application further relates to a crucible for a translucent waveguide plasma light source having the same properties as the method applied in the crucible manufacturing process, which method expands the tube and / or contracts the waveguide body. Thereby bringing the tube and the waveguide body close to each other and closely contacting each other. In one embodiment, the operation to produce the crucible intermediate product for the translucent waveguide plasma light source is as follows. a) The waveguide body (2) is preheated, the waveguide body is arranged on the support so that the bore is concentric with the tube 4, the tube is supported by the chuck, and connected to the expansion means Is done. b) The tube is heated with the chuck rotating so that the heating is uniform. c) When it is detected that the temperature of the tube is the softening point of the quartz of the tube, the tube stops rotating and enters the bore (3) of the waveguide body (2). d) The intrusion stops when it is detected that the closed end (of the tube) has reached the predetermined protrusion (18). e) At the same time as the invasion stops, the inflation gas enters the tube and causes the tube to expand somewhat, bringing the outer surface (5) of the tube into intimate contact with the surface (6) of the bore (4) and also securing the bore tube. Thus, the expansion causes the tube just outside the bore to expand. [Selection] Figure 1

Description

  The present invention relates to LUWPL, a crucible for a translucent waveguide plasma light source.

European Patent No. 1307899 we have acquired includes a waveguide configured to connect to an energy source and receive electromagnetic energy, and connect to and receive electromagnetic energy from the waveguide. A light source comprising a bulb containing a gas filler that emits light,
(A) The waveguide is basically composed of a dielectric material having a dielectric constant greater than 2, a loss tangent less than 0.01, and a DC breakdown limit value greater than 200 kilovolts / inch as 1 inch 2.54 cm. With a body
(B) The size and shape of the waveguide can hold at least one electric field maximum value in the main body of the waveguide at at least one operating frequency of frequencies from 0.5 to 30 GHz. And
(C) the cavity is dependent on the first side of the waveguide;
(D) The valve is disposed in a portion where the electric field is maximum in the cavity during operation, and the gas filling material emits plasma that emits light when receiving microwave energy from the resonating waveguide body. Forming,
(E) A microwave supply unit provided inside the waveguide body is configured to receive microwave energy from the energy source, and is in close contact with the waveguide body.
A light source characterized in that is claimed.

Also, in our European Patent No. 218829, there is a light source driven by microwaves, the light source comprising:
A body having a cavity sealed therein;
A Faraday box that surrounds the main body, and a Faraday box that confines microwaves;
The body is a resonant waveguide contained in the Faraday box;
In said cavity, a filler that can be excited by the energy of microwaves, which is filled in order to generate a light-emitting plasma therein;
An antenna provided in the body for transmitting microwave energy that induces plasma in the filler, the antenna comprising:
A connection extending outside the body for coupling with a microwave energy source;
Have
The body is a plasma seal made of a solid made of a translucent material for the light exiting from it,
The Faraday box is at least partially transparent for light from the plasma sealant,
A light source is described and claimed that is arranged such that light from the plasma in the cavity can pass through the plasma seal and is emitted through the box.

  This is referred to as our Light Emitting Resonator patent or LER patent. The main claim of the light source mentioned immediately above is based on the disclosure of our first mentioned European patent 1307899 in relation to the prior art part.

Our European Patent Application No. 08875663.0 (International Publication No. 20110055275) includes:
A translucent waveguide made of a solid dielectric material,
A translucent Faraday box surrounding the waveguide, at least partially transmitting light, and transmitting light radially;
A valve-type cavity resonator inside the waveguide and the Faraday box;
An antenna recess inside the waveguide and the Faraday box;
A translucent waveguide made of a solid dielectric material having
A valve having a microwave excitable filling, which is received in the valve cavity resonator;
A light source comprising is described and claimed.

  Since the translucent waveguide forms a clamshell around the bulb, we will refer to this as our clamshell application.

As used in our LER patent, our clamshell application, and in this specification,
・ "Microwave" does not mean a specific frequency band. We use “microwave” to mean a three-digit frequency band from around 300 MHz to around 300 GHz.
-“Translucent” means that the material of the translucent object is transparent or translucent.
“Plasma crucible” means a sealed body that confines the plasma, the latter being in the void space when the void space filler is excited by microwave energy from the antenna. .
A Faraday box means a conductive covering that confines electromagnetic radiation and does not substantially transmit electromagnetic waves of at least a predetermined operating frequency such as microwaves.

  The LER patent, the clamshell application, and several LER improvement applications are common in the following respects.

A microwave plasma light source; a Faraday box that partitions the waveguide and, for light emission, is at least partly translucent, usually at least partly transparent, and usually has an opaque covering;
A body of translucent solid dielectric material that forms the waveguide in the Faraday box;
A closed cavity in a waveguide containing a material excitable by microwaves;
A supply means for introducing an electromagnetic wave for exciting the plasma into the waveguide,
When an electromagnetic wave having a predetermined frequency is introduced, plasma is created in the cavity and is arranged to emit light from the Faraday box.

  In our patent application PCT / GB 2011/001744 (our 744 application) we defined a translucent waveguide plasma light source as follows:

A microwave plasma light source,
-A molded body made of a translucent solid dielectric material,
With closed cavities containing materials that can be excited by electromagnetic waves, usually microwaves,
・ Faraday box, this is
・ Partition the waveguide,
For light emission, at least partly translucent, usually at least partly transparent,
・ It usually has an opaque cover,
-Surrounding the molded body,
Supply means for introducing electromagnetic waves, usually microwaves, into the waveguide to excite plasma,
The arrangement of the light source is a microwave that generates a plasma in the cavity and emits light from the Faraday box when an electromagnetic wave having a predetermined frequency, usually a microwave, is introduced. Plasma light source.

  In the preferred embodiment of our LER patent, the cavity is formed directly in a translucent waveguide, typically made of quartz. As a result, the quartz material is exposed to high heat by heat radiation from the plasma and heat conduction of the gas surrounding the plasma. In this sense, the term “solid plasma crucible” is used in the LER patent in the sense that it is exposed to high heat, and crucible refers to a container for high heat materials. When a minute crack occurs in the crucible member due to the plasma, the minute crack propagates in the member due to exposure to heat, causing a problem.

  In our clamshell application, such a cavity and a quartz bulb with excitable material are provided separately from the translucent waveguide and are inserted inside the translucent waveguide. There is no problem. The waveguide is bisected so that the valve is held between them, or it is formed singly with a bore that receives the valve.

  An object of the present invention is to provide an improved crucible for a LER-type translucent waveguide plasma light source.

Means for Solving the Invention

According to a first aspect of the present invention, there is provided a crucible for a translucent waveguide plasma light source, the crucible comprising:
A waveguide body having a bore and made of a translucent material;
A tube made of a translucent material provided in the bore, wherein both ends of the tube are closed ends, and the excitation material is contained in a cavity formed in the bore between the closed ends. Included, the tube being in intimate contact with the translucent material of the waveguide body; and
It comprises.

According to a second aspect of the present invention, there is provided an intermediate product during manufacture of the crucible according to the first aspect, the intermediate product comprising: a waveguide body having a bore and made of a translucent material;
A tube provided in the bore, in intimate contact with the translucent material of the waveguide body, and made of a translucent material;
It comprises.

  Usually, the waveguide body is made of quartz glass, and the tube is made of a drawn quartz glass tube, and does not include minute cracks that exist when processing the bore of the waveguide body. Hereinafter, “quartz” is used as a term indicating “quartz glass”.

  When using the crucible of the present invention, the bore is protected from the effects from the plasma gas and the intense heat associated with bringing the plasma-containing cavity close. By closely contacting the waveguide and the waveguide body inside the bore, it becomes possible to make the thermal and electrical characteristics (such as thermal conductivity from the bore) continuous in all parts of the crucible. However, although the thermal conductivity of quartz (ideal material) is low, this is advantageous for heating the crucible cavity.

  Typically, the translucent material of the tube is the same as the waveguide body, or at least generally close to the waveguide body. Here, “substantially close” intends that one or more materials may contain an additive that changes the optical transmittance and / or the dielectric constant.

  In the metal processing technology, the parts are thermally expanded / contracted or the parts are pressurized to ensure close contact. However, the quartz parts are easily broken by the pressure.

According to a third aspect of the present invention, there is provided a method for producing the crucible according to the first aspect, the method comprising: providing a bore inside a translucent waveguide body;
-Inserting a translucent tube into the bore;
Inflating the tube and / or contracting the waveguide body to bring the tube and the waveguide body into close contact in the bore;
Is included.

Although expansion and / or contraction could be achieved by heating the waveguide body and / or cooling the tube before inserting the tube into the bore, preferably a quartz tube Before inserting, heat until the tube softens,
・ When inserting, expand the tube,
Is achieved.

  Although it seems that the heated tube could be inserted into a cooled translucent waveguide body, we believe it is preferable to preheat the waveguide body before insertion, thereby The tube does not tend to shrink away from the waveguide body upon cooling after expansion.

  The tube may have a uniform diameter, but at least to seal the large diameter portion sized to be complementary to the bore and the encapsulated excitation material. It is preferable to provide a small diameter portion.

  The distal end of the tube and / or the insert may be prevented from being sealed during insertion, but is preferably sealed prior to insertion. The bore can be a blind bore with the closed end of the tube inserted to the bottom of the bore, but the bore is inserted with the distal end extending to a predetermined length. And it is preferable that it is a through-bore.

  Preferably, the (tube) is continuously inserted up to the stop on the side of the waveguide body opposite the insertion surface. The stop can be a physical stop, which prevents the closed end of the tube from extending away from the waveguide body during expansion. There is an advantage of supporting the closed end. However, the optical stop can be used individually or in combination with the physical stop. Here, the optical stop means that when the tube is correctly placed, the closed end cuts off the light beam, and by the blocking, the operating device that advances the tube stops the advance (of the tube), This means something that is expanded by applying internal pressure. Alternatively, other methods can be considered for detecting that the closed end of the tube has reached the stop position.

  Conveniently, the distal end is fully inserted through the bore so that immediately behind the opposite end orifice of the bore, the tube expands larger than the diameter of the bore; There, the tube is not constrained by the bore, and the tube is physically limited in axial movement relative to the waveguide body. For this purpose, the tube is heated for a length exceeding the length of the bore.

  Alternatively, the bore can be a through-bore, but the far end of the tube is placed so that it is flush with the side of the waveguide body opposite the place where the tube is inserted into the waveguide body. It is also possible to insert.

  Here too, the tube is preferably heated while being observed with a thermometer such as an infrared sensor. Here, when the temperature becomes so soft that the tube can expand, but hard enough to allow the tube to be inserted, the actuator can immediately advance the tube.

  The sealing portion at the proximal end of the tube can be processed by ordinary glass processing technology, and the material of the tube can be upset by the glass processing technology and fused with the material of the waveguide body. However, it is not necessary to do so. Furthermore, it is also possible to upset the end portion (of the tube) that was originally sealed so as to be more closely attached to the side surface of the waveguide body.

  The unsealed end of the tube is preferably (i.) Initially after insertion of the excitation material, the end of the portion remote from the waveguide body is sealed, and (ii.) In the state where the length is removed, the end of the portion close to the waveguide body is sealed in two stages.

Preferably after insertion of the excitation material and before the first sealing:
The excitation material is sublimated and recondensed inside the expanding part of the tube, i.e. the extension from the waveguide body inside the tube, and the volatile impurities introduced with the excitation material are evacuated;
After initial sealing:
The excitation material condensed in the tube outside the waveguide body is sublimated, re-introduced inside the expanded tube inside the waveguide body, i.e. in the closed end first sealed, before final sealing. Condensate.

  In order to facilitate understanding of the present invention, specific embodiments will be described with reference to specific examples and attached drawings.

FIG. 1 is a diagram of an apparatus for producing a translucent crucible according to the present invention. FIG. 2 is a cross-sectional view of the intermediate product in the crucible manufacturing process. FIG. 3 is a cross-sectional perspective view of the crucible after manufacture. FIG. 4 is a view similar to FIG. 2 and is a modification of the stepped tube before sealing. FIG. 5 is a cross-sectional view similar to FIG. 4 and is a modification of the translucent crucible after sealing.

  Referring to the drawings, a crucible 1 according to the present invention is formed of a quartz glass waveguide body 2, which is generally 49 mm in diameter and 20 mm in length, in a Faraday box that closely surrounds the waveguide body. Thus, it is designed to operate at 2.45 GHz microwave resonance. The waveguide body has a central bore 3 with a diameter of 6 mm, and the bore is polished until it becomes optically transparent, but it is polished enough to remove all small cracks that occur during the drilling process. There is no need to be. The waveguide body also has an eccentric bore for receiving an antenna for introducing microwaves.

  A drawn quartz tube 4 is received inside the central bore, the quartz tube having a nominal wall thickness of 1 mm, ie a nominal outer diameter of 6 mm, and the outer surface 5 of the quartz tube is connected to an optically transparent bore surface 6. It is in close contact. Here, the crucible practically has a property like a single quartz having a 4 mm bore 7 at the center of a drawn tube subjected to surface finishing. We assume that the contact adhesion test is as follows. That is, the end portion is scraped off at about 3 mm from each end face 8 of the main body through a reference tube or bore. When the pipes are in close contact, it can be expected to resist pressing from the bore. Note that we have proposed another crucible structure in the co-pending application that has a structure such that the tube is not in full contact.

  Both ends of the tube are sealed. One end 9 (of the tube) is generally formed before the tube 4 is inserted into the bore 2 and expands slightly upon insertion. The other end 10 (of the tube) has a sealing part, which is formed by a glass blowing technique after the bore is inserted. The sealed tube is filled with a material that can be excited by microwaves and forms a luminescent plasma on the axis of the tube.

The crucible production is carried out in an apparatus comprising:
A support 11 of a translucent waveguide body 2 which is perforated, optionally polished and preheated to near the softening point, but from a preheating oven (not shown) The support body 11 is characterized in that the body is not heated to the extent that the shape of the body collapses when moving to
A chuck 12 for holding the tube 4, the tube already having one end 9 sealed, and no part of the end has a larger diameter than the other part of the tube; 4 is held concentrically with the bore 3, and a chuck 12,
A radiant heater for forming the expansion portion 15 of the tube, wherein the tube has a thickness obtained by adding a margin to the thickness of the main body so that the tube is received by the main body 1. Vessel 14;
A thermometer 16 for monitoring the temperature at which the tube is heated;
Means 17 for optically detecting that the tube is inserted through the body and up to a predetermined protrusion 18;
A means 19 for injecting inflation gas into the tube, the inflation means being
A compressed gas supply source 20;
An injection valve 21;
A flexible connection 22 for allowing the tube 4 and the chuck to advance when the tube 4 is inserted;
Means 19 characterized in that it comprises a rotation connection 23 for allowing the tube 4 to rotate during heating;
Means 24 for advancing the chuck and tube;
A controller 25;

Under the control of the controller 25, the operation of this apparatus is as follows.
a) Preheating the waveguide body 2 and arranging the waveguide body on the support so that the tube 4 supported by the chuck and connected to the expansion means and the bore of the waveguide body are concentric.
b) Heat the tube while the chuck is rotating so that the heating is uniform.
c) When it is detected that the temperature of the tube is the softening point of the quartz of the tube, the rotation of the tube is stopped and the tube is advanced to the bore 3 of the waveguide body 2.
d) When it is detected that the closed end of the far end (of the tube) has reached the predetermined protrusion 18, the forward movement is stopped.
e) At the same time as the advancement is stopped, inflation gas is injected into the tube, causing the tube to expand slightly, bringing the tube outer surface 5 into intimate contact with the surface 6 of the bore 4, and by the expansion, The outer tube expands to ensure that the tube in the bore is secured.
f) The intermediate product thus produced can be set aside and cooled, partially cooled, or in some cases processed hot.

Further stages of processing are as follows:
g) shutting off the inflation gas supply and connecting to a vacuum pump (not shown);
h) vacuuming the tube;
i) stage of insertion of the excitation material pellet (care must be taken not to heat the crucible intermediate product to volatilize the excitation material),
j) stage of injection of inert gas into the vacuum tube;
k) a processing stage for heating the tube away from the waveguide body and sealing the tube;
l) Heating the tube close to the waveguide body, upsetting the seal to expand to a larger diameter than the original tube diameter, and processing to form a second final seal close to the waveguide Stage. Only the length of the middle portion of the tube between the first seal and the second seal is removed.

  The present invention is not limited to the details of the embodiments described above. In particular, the chuck does not need to be rotated when the tube is placed so as to be inserted vertically downward into the translucent waveguide body, and a heater is installed to prevent distortion of the tube during bending. It is possible to use. If such an arrangement is utilized, the chuck can simply be replaced by a clamp.

  Furthermore, the pellets of the excitation material may contain volatile impurities, especially hydrogen iodide, while the excitation material itself is solid at room temperature and is likely to volatilize at higher temperatures than the volatile impurities (volatilization temperature) May be. In order to remove impurities, in step (i) above, pellets are introduced while the crucible intermediate product is still hotter than the volatilization temperature of the impurities. When the temperature is lowered, heat is applied to the closed end 9 of the tube to volatilize the impurities, and the (impurities) can be discharged through the vacuumed tube. When the intermediate product is sufficiently cooled, the sublimated pellet material condenses in the expanded portion of the tube inside the translucent waveguide body 2. The tube extending from the waveguide body can be cooled by an air flow adjacent to the waveguide body for recondensation. Thereafter, an inert gas is introduced as in step (j) and the distal end of the tube is sealed as in step (k). The closed end and / or the expanding portion are cooled together with the waveguide body 2. Prior to sealing as in step (l), at least in the part where the excitation material is condensed in the tube, that part is heated again to sublimate the material, and the material is opened to the open end 9 or the lead. Recondensation at the tube expansion part of the waveguide body. The sealing step (l) can be completed as described above with the excitation material filled.

  The radiant heater can be an electric heater, a gas torch, a dielectric heating carbon block, or the like.

  The optical detection means may be a photodiode LED. It is also possible to use a camera equipped with appropriate image recognition software. Again, it is possible to use the detection means in combination with a physical stop.

  Normally, if the excitation material / plasma cavity extends over the entire layer of the waveguide body, the light source is expected to provide the best optical performance, with all layers from the end face where the closed end of the tube extends. Remote stops are also included. However, we may prefer to provide a stop at this end face so that all expansion of the tube is within the bore of the waveguide.

  It seems that the best results can be obtained if the bore surface 6 is polished until it is optically transparent, but otherwise it may be pre-processed, for example by means of fine grinding, if not as transparent. It is also possible to do.

  Note that in terms of tube wall thickness, the 1 mm dimension is just one example. We expect that quartz tubes with 1.5 mm, 2 mm, or other wall thickness can be expanded, and that tubes with a diameter of 6 mm are also expandable. Although a bore with a nominal diameter of 6 mm and a pipe with an outer diameter of 6 mm were referenced, for reasons of normal engineering compatibility, a gap of 0.5 mm is usually required before expansion, typically, It is required to make a large size by 0.5 mm and to expand the tube through this gap. In order to form a 4 mm bore, the unexpanded bore is less than 4 mm.

  Furthermore, the expanded tube does not need to extend beyond the end face of the waveguide body opposite the insertion face, and the closed end sealed in the first stage is the opposite end of the waveguide body to the insertion face. It can be inserted so that it is flush with the surface. Such a modification is shown in FIGS. The quartz waveguide body 102 includes a central bore 103. The quartz tube 104 processed into a capsule shape includes a large-diameter parallel end portion 1041 having an outer diameter that complements the bore 103. The quartz tube is machined to have a flat end 1042, which is flush with one side 1021 of the waveguide body in the finished product. The quartz tube is also processed to include a medium diameter portion 1043 and a small diameter portion 1044. The quartz tube can be formed by fusing two or more parts. The shoulder portion 1045 between the large diameter portion 1041 and the medium diameter portion 1043 is separated from the flat end by a distance equivalent to the thickness of the main body. Therefore, when the heated large diameter portion is inserted into the bore 103 and its flat end 1042 is expanded to be flush with the side 1021, the shoulder is flush with the other surface 1022 of the waveguide body. Become. After the excitation material is inserted, impurities are removed, and preliminary sealing is performed, when the final sealing is performed at the intermediate portion, the sealing tip portion protrudes from the other surface 1022.

Claims (25)

A crucible for a translucent waveguide plasma light source, wherein the crucible is:
A waveguide body having a bore and made of a translucent material;
A tube made of a translucent material provided in the bore, this tube being
-Both ends are closed
A cavity formed in a bore between the sealed ends includes the excitation material;
-It is in close contact with the translucent material of the waveguide body,
Crucible for translucent waveguide plasma light source. 2. The translucent waveguide plasma light source according to claim 1, wherein the translucent material of the tube is the same material as the waveguide body, or at least substantially the same material as the waveguide body. The translucent waveguide plasma light source according to claim 1 or 2, wherein the waveguide body and the tube are made of quartz glass. 4. The translucent waveguide plasma light source according to claim 3, wherein the quartz tube is a drawn quartz tube. The intermediate product for producing the crucible according to any one of claims 1 to 4, wherein the intermediate product is
A waveguide body having a bore and made of a translucent material;
A tube made of a translucent material provided in the bore in close contact with the translucent material of the waveguide body;
An intermediate product of the crucible production, characterized in that The crucible manufacturing method according to any one of claims 1 to 4,
Providing a translucent waveguide body with a bore;
-Inserting a translucent tube into the bore;
Expanding the tube and / or shrinking the waveguide body to bring the tube and the waveguide body into close contact with each other in the bore. The method of claim 6, wherein the expansion and / or contraction is accomplished by heating the waveguide body or cooling the tube prior to inserting the tube into the bore. Said expansion and / or contraction is caused by quartz tube:
Heating the tube to the softening point before insertion,
・ When inserting, expand the tube,
7. The method of claim 6, wherein the method is accomplished by: 9. The method of claim 8, wherein the heated tube is inserted into a cooled translucent waveguide body. 9. The method of claim 8, wherein the waveguide body is preheated prior to insertion of the heated tube. When the tube is heated while being observed with a thermometer, such as an infrared sensor, the tube is soft enough to expand, but hard enough to allow the tube to be inserted, the actuator immediately 9. The method of claim 8, wherein the tube is advanced. 12. A method according to any one of claims 6 to 11, wherein the distal end and / or the insertion part of the tube are not sealed during insertion. 12. A method according to any one of claims 6 to 11, characterized in that the distal end and / or the insert of the tube is sealed before insertion. 14. The method of claim 13, wherein the bore is a blind bore and the closed end of the tube is inserted to the bottom of the bore. The bore is a through-bore, and the distant end portion is inserted so as to extend to a predetermined length from a side surface of the waveguide body opposite to a place where the tube is inserted into the waveguide body. 14. A method according to claim 13 characterized in that The distal end is fully inserted through the bore, and immediately behind the opposite end orifice of the bore, the tube expands larger than the diameter of the bore, where the tube constrains the bore. 16. The method of claim 15, wherein the tube is physically limited in axial movement relative to the waveguide body, and the tube is heated for a length that exceeds the length of the bore. The bore is a through-bore, and the distant end portion is inserted so as to be flush with a side surface of the waveguide body opposite to a place where the tube is inserted into the waveguide body. The method according to claim 13. 15. The method according to claim 14, wherein the distant end portion is inserted to a stop portion on the side surface of the waveguide body that is opposite to the insertion surface. The method of claim 15, wherein the stop is a physical stop. The stop part is an optical stop part that is used individually or an optical stop part that is used in combination with the physical stop part, and when the tube is correctly placed, a light beam is emitted by the closed end. 16. The method of claim 15, wherein an actuating device that is supplied and shut off and advances the tube with the shut-off stops advancing and inflates the tube with internal pressure. 21. A method according to any one of claims 6 to 20, wherein the tube has a uniform diameter. The tube is a step-shaped tube including at least a large-diameter portion whose size is adjusted to be complementary to the bore and a small-diameter portion for sealing the encapsulated excitation material. 21. A method according to any one of claims 6-20. The proximal end of the tube is sealed by glass processing technology, and preferably, the glass processing technology includes a technology for upsetting the material of the tube and fusing it with the material of the waveguide body, and sealing. The method according to claim 21, further comprising: an upsetting technique for bringing the formed distal end portion into closer contact with a side surface of the waveguide body. The proximal end of the tube is (i.) Initially sealed after the insertion of the excitation material, the portion remote from the waveguide body, and (ii.) The length of the middle portion of the tube is then removed. The method according to any one of claims 14 to 19, wherein sealing is performed in two stages, in which the portion close to the waveguide body is sealed. After insertion of the excitation material and before the first sealing,
The excitation material is sublimated and recondensed within the expanding portion of the tube, i.e., within the extension from the waveguide body within the tube;
Volatile impurities introduced with the excitation material are evacuated;
After initial sealing:
The excitation material condensed in the tube outside the waveguide body is inside the expanded tube inside the waveguide body, i.e. in the closed end first sealed, before final sealing. The method according to claim 21, wherein sublimation and recondensation are performed.

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