EP0281858B1 - High-power gyrotron for generating electromagnetic millimeter or submillimeter waves - Google Patents
High-power gyrotron for generating electromagnetic millimeter or submillimeter waves Download PDFInfo
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- EP0281858B1 EP0281858B1 EP88102786A EP88102786A EP0281858B1 EP 0281858 B1 EP0281858 B1 EP 0281858B1 EP 88102786 A EP88102786 A EP 88102786A EP 88102786 A EP88102786 A EP 88102786A EP 0281858 B1 EP0281858 B1 EP 0281858B1
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- 230000003287 optical effect Effects 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 4
- 230000005670 electromagnetic radiation Effects 0.000 claims description 3
- 239000004020 conductor Substances 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 claims 1
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- 238000007373 indentation Methods 0.000 claims 1
- 238000010894 electron beam technology Methods 0.000 description 7
- 230000005855 radiation Effects 0.000 description 5
- 238000010521 absorption reaction Methods 0.000 description 4
- 230000004927 fusion Effects 0.000 description 3
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000013016 damping Methods 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005672 electromagnetic field Effects 0.000 description 2
- 239000006096 absorbing agent Substances 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
- H01J25/02—Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators
- H01J25/025—Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators with an electron stream following a helical path
Definitions
- the invention relates to a device for generating electromagnetic millimeter or submillimeter waves of high intensity. It relates in particular to a high-performance gyrotron according to the preamble of claim 1.
- the high-performance gyrotron is intended for use in nuclear fusion for heating the fusion plasma.
- a gyrotron of the type mentioned is known, for example, from an article by TA Hargeaves et al., Int. J. Electronics 57, 977 (1984) or also from an article by A. Perrenoud et al., Int. J. Electronics 57, 985 (1984).
- the resonator of the known gyrotron formed by the two concave mirrors is a so-called open resonator.
- the two concave mirrors are, at least in their immediate vicinity, not surrounded by a housing or the like.
- a generator for UHF waves emerges from the published patent application EP-A1-0 124 396 (Mourier).
- an electron beam runs along an x direction.
- Two mirrors form a quasi-optical resonator, the axis of which lies in the y direction.
- a static magnetic field acts in the z direction.
- This generator works on a completely different principle than the gyrotron according to Hargreaves or Perrenoud. Mourier does disclose a cylindrical housing that completely encloses the quasi-optical resonator. However, the axis of the housing lies in the z direction and is equipped with absorbers to prevent parasitic resonances.
- a high-energy electron beam passes through the resonator along a magnetic field.
- the electrons of the electron beam move along the magnetic field on spiral tracks with an orbital frequency corresponding to the cyclotron frequency, which is proportional to the strength of the magnetic field. They interact with an alternating electromagnetic field built up in the resonator.
- the modes excited in the resonator are of the TEM mnp type, the indices m and n denoting transverse modes and the index p denoting longitudinal modes (see also H. Kogelnik, 1966, Modes in Optical Resonators; Lasers, Vol. 1, edited by AK Levine, New York: Marcel Dekker, p. 295).
- the longitudinal TEM oop modes are selected because they have the lowest diffraction losses.
- the thermal load on the concave mirrors does not become too great in the envisaged application for nuclear fusion (the field power in the resonator can be a few megawatts), they must have a certain minimum size that is significantly (up to two orders of magnitude) larger than the wavelength of the electromagnetic radiation to be generated.
- the p of the modes excited in the resonator is therefore in the range between 40 and 400. This has the consequence that the frequency spacing between two adjacent modes TEM oop and TEM oo (p + 1) is significantly smaller than the instability frequency band of the gyrotron, which raises the problem of mode competition (see, for example, Bondeson et al., Infrared and Millimeter Waves 9 , 309 (1984)).
- the open, quasi-optical resonator has been designed such that it is mode-selective is, that a TEM oop mode is excited in it alone or at least preferably over other neighboring modes TEM oop ⁇ 1 (see A. Perrenoud et al., Int. Journal of Infrared and Millimeter Waves 7 , 427 (1986) and A. Perrenoud et al., Int. Journal of Infrared and Millimeter Waves 7 , 1813 (1986)).
- non-Gaussian modes additionally excited by the housing provided according to the invention are related their intensity is relatively weak and tolerable compared to the desired Gaussian TEM oop modes.
- the coupling efficiency is increased to 100% by the invention.
- the radiation to the environment is practically completely prevented by the housing provided according to the invention.
- Other devices such as Deflection coils for the electron beam or a prebuncher can be set up in the immediate vicinity of the resonator.
- Fig. 1 and 2 denote two concave mirrors, which are arranged opposite one another at a distance d on an optical axis.
- the optical axis coincides with a coordinate axis or direction Y in FIG. 1.
- the two concave mirrors 1 and 2 together form a quasi-optical resonator.
- a high-energy electron beam 3 passes through the quasi-optical resonator in the middle between the two concave mirrors 1, 2 in the direction of a coordinate axis Z perpendicular to the direction Y.
- a largely homogeneous magnetic field (not shown in FIG. 1) between the two concave mirrors is also oriented in this way 1 and 2.
- the electrons of the electron beam 3 move in spiral paths around the magnetic field lines. This is indicated by the spiral line in Fig. 1.
- the quasi-optical resonator of FIG. 1 is arranged in a housing 4.
- the housing 4 is a cylinder, the axis of which coincides with the optical axis of the concave mirror 1, 2. It is, at least predominantly, electrically conductive.
- the length of the housing extends over a little more than the spacing range d between the concave mirrors 1, 2.
- the ratio of the diameter of the housing 4 to the diameter of the mirrors 1, 2 is a parameter dependent on the respective application. In the case of a resonator with 2% diffraction losses according to a value of approximately 1.4 for this ratio, in order to suppress the undesirable, non-Gaussian modes. The same applies if the electromagnetic field power is only coupled out at one end.
- the cylindrical housing 4 has connecting flanges 4.1. Only microwave sections 5 shown in sections are flanged to the connecting flanges. The electromagnetic waves generated in the quasi-optical resonator are fed to the output of the gyrotron via the microwave conductor 5. Finally, the housing 4 also has through openings 4.2 for the electron beam 3.
- the housing 4 Due to the housing 4, the radiation of electromagnetic radiation into the surroundings of the quasi-optical resonator or the high-energy gyrotron is practically completely prevented and an optimal decoupling efficiency is achieved.
- the desired mode purity can be improved in particular by using concave mirrors 1, 2 with high negative g factors down to -.8.
- the mode purity can be further improved by selective damping of the undesirable, non-Gaussian modes.
- Calculations show that the strongest of these modes are primarily reflected once in a section in the region in the middle between the two concave mirrors 1, 2 on the inner wall of the housing 4.
- the undesired non-Gaussian modes can thus be selectively suppressed in a simple manner.
- the extension D of the named, specially designed section of the housing 4 in the direction Y of the optical axis of the two concave mirrors 1, 2 should preferably extend over a maximum of about 1/5 of the distance range (d) between the concave mirrors.
- concave mirrors 1, 2 which have a stepped structure, as is shown for example for concave mirror 1 in FIG. 1.
- the concave mirror should in particular have two mirror surfaces which are offset in steps from one another by one or more very multiples of half the wavelength of the desired radiation.
- the radii of the staggered mirror surfaces, designated in Fig. 1 with r11 and r12, should be dimensioned relative to each other so that the same energy flow is applied to all mirror surfaces.
- the aforementioned measures could also be used to optimize other parameters, for example to reduce the radius r4 of the housing 4.
- concave mirrors 1, 2 With a geometry deviating from the spherical geometry, the electromagnetic efficiency of the gyrotron according to the invention can be improved.
- concave mirrors are advantageous which, as shown for example in FIG. 2, have different radii of curvature in two mutually perpendicular directions X and Z. R X , R Z have. The direction Z of FIG. 2 should coincide with the Z direction of FIG. 1.
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Description
Die Erfindung bezieht sich auf eine Vorrichtung zur Erzeugung elektromagnetischer Millimeter- oder Submillimeterwellen hoher Intensität. Sie betrifft insbesondere ein Hochleistungs-Gyrotron gemäss Oberbegriff des Anspruchs 1. Das Hochleistungs-Gyrotron ist vorgesehen zur Verwendung bei der Kernfusion zur Heizung des Fusionsplasmas.The invention relates to a device for generating electromagnetic millimeter or submillimeter waves of high intensity. It relates in particular to a high-performance gyrotron according to the preamble of claim 1. The high-performance gyrotron is intended for use in nuclear fusion for heating the fusion plasma.
Ein Gyrotron der genannten Art ist beispielsweise bekannt aus einem Artikel von T.A. Hargeaves et al., Int. J . Electronics 57, 977 (1984) oder auch aus einem Artikel von A. Perrenoud et al., Int. J. Electronics 57, 985 (1984).A gyrotron of the type mentioned is known, for example, from an article by TA Hargeaves et al., Int. J. Electronics 57, 977 (1984) or also from an article by A. Perrenoud et al., Int. J. Electronics 57, 985 (1984).
Der durch die beiden Hohlspiegel gebildete Resonator des bekannten Gyrotrons ist ein sogenannter offener Resonator. Die beiden Hohlspiegel sind, zumindest in ihrer näheren Umgebung, nicht von einem Gehäuse oder dergleichen umgeben.The resonator of the known gyrotron formed by the two concave mirrors is a so-called open resonator. The two concave mirrors are, at least in their immediate vicinity, not surrounded by a housing or the like.
Aus der veröffentlichten Patentanmeldung EP-A1-0 124 396 (Mourier) geht ein Generator für UHF-Wellen hervor. In diesem Generator läuft ein Elektronenstrahl entlang einer x-Richtung. Zwei Spiegel bilden einen quasi-optischen Resonator, dessen Achse in y-Richtung liegt. Ein statisches Magnetfeld wirkt in z-Richtung. Dieser Generator arbeitet damit nach einem völlig anderen Prinzip als das Gyrotron nach Hargreaves oder Perrenoud. Mourier offenbart zwar ein zylindrisches Gehäuse, das den quasi-optischen Resonator vollständig umschliesst. Die Achse des Gehäuses liegt jedoch in z-Richtung und ist mit Absorbern ausgestattet um parasitäre Resonanzen zu verhindern.A generator for UHF waves emerges from the published patent application EP-A1-0 124 396 (Mourier). In this generator, an electron beam runs along an x direction. Two mirrors form a quasi-optical resonator, the axis of which lies in the y direction. A static magnetic field acts in the z direction. This generator works on a completely different principle than the gyrotron according to Hargreaves or Perrenoud. Mourier does disclose a cylindrical housing that completely encloses the quasi-optical resonator. However, the axis of the housing lies in the z direction and is equipped with absorbers to prevent parasitic resonances.
In dem Gyrotron durchsetzt ein Hochenergie-Elektronenstrahl den Resonator entlang eines magnetischen Feldes. Dabei bewegen sich die Elektronen des Elektronenstrahls entlang des Magnet-feldes auf spiralförmigen Bahnen mit einer der Zyklotronfrequenz entsprechenden Umlauffrequenz, die zur Stärke des Magnetfeldes proportional ist. Sie wechselwirken mit einem im Resonator aufgebauten elektromagnetischen Wechselfeld.In the gyrotron, a high-energy electron beam passes through the resonator along a magnetic field. The electrons of the electron beam move along the magnetic field on spiral tracks with an orbital frequency corresponding to the cyclotron frequency, which is proportional to the strength of the magnetic field. They interact with an alternating electromagnetic field built up in the resonator.
Die im Resonator angeregten Moden sind vom Typ TEMmnp, wobei die Indizes m und n Transversalmoden und der Index p Longitudinalmoden bezeichnen (vgl. auch H. Kogelnik, 1966, Modes in Optical Resonators; Lasers, Vol. 1, herausgegeben von A.K. Levine, New York: Marcel Dekker, S. 295). In dem bekannten Gyrotron werden nur die longitudinalen TEMoop -Moden selektiert, da sie die geringsten Diffraktionsverluste aufweisen.The modes excited in the resonator are of the TEM mnp type, the indices m and n denoting transverse modes and the index p denoting longitudinal modes (see also H. Kogelnik, 1966, Modes in Optical Resonators; Lasers, Vol. 1, edited by AK Levine, New York: Marcel Dekker, p. 295). In the known gyrotron, only the longitudinal TEM oop modes are selected because they have the lowest diffraction losses.
Damit die thermische Belastung der Hohlspiegel bei der in Aussicht genommenen Anwendung bei der Kernfusion nicht zu gross wird (die Feldleistung im Resonator kann einige Megawatt betragen) müssen diese eine gewisse Mindestgrösse aufweisen, die wesentlich (um bis zu zwei Grössenordnungen) grösser als die Wellenlänge der zu erzeugenden elektromagnetischen Strahlung ist. Das p der im Resonator angeregten Moden liegt dadurch im Bereich zwischen 40 und 400. Dies hat zur Folge, dass der Frequenzabstand zwischen zwei benachbarten Moden TEMoop und TEMoo(p+1) wesentlich kleiner ist als das Instabilitäts-Frequenzband des Gyrotrons, was das Problem einer Moden-Konkurrenz aufwirft (vgl. z.B. Bondeson et al., Infrared and Millimeter Waves 9, 309 (1984)).So that the thermal load on the concave mirrors does not become too great in the envisaged application for nuclear fusion (the field power in the resonator can be a few megawatts), they must have a certain minimum size that is significantly (up to two orders of magnitude) larger than the wavelength of the electromagnetic radiation to be generated. The p of the modes excited in the resonator is therefore in the range between 40 and 400. This has the consequence that the frequency spacing between two adjacent modes TEM oop and TEM oo (p + 1) is significantly smaller than the instability frequency band of the gyrotron, which raises the problem of mode competition (see, for example, Bondeson et al., Infrared and Millimeter Waves 9 , 309 (1984)).
Bei dem bekannten Gyrotron ist es jedoch gelungen, den offenen, quasi-optischen Resonator derart auszubilden, dass er modenselektiv ist, d.h. dass in ihm eine TEMoop -Mode allein oder zumindest bevorzugt gegenüber anderen, benachbarten Moden TEM oop±1 angeregt wird (vgl. A. Perrenoud et al., Int. Journal of Infrared and Millimeter Waves 7, 427 (1986) and A. Perrenoud et al., Int. Journal of Infrared and Millimeter Waves 7, 1813 (1986)).In the known gyrotron, however, the open, quasi-optical resonator has been designed such that it is mode-selective is, that a TEM oop mode is excited in it alone or at least preferably over other neighboring modes TEM oop ± 1 (see A. Perrenoud et al., Int. Journal of Infrared and Millimeter Waves 7 , 427 (1986) and A. Perrenoud et al., Int. Journal of Infrared and Millimeter Waves 7 , 1813 (1986)).
Dem Vorteil der erzielbaren Moden-Selektivität der offenen Resonatorstruktur stehen jedoch vor allem zwei Nachteile entgegen:
- Die Auskopplungs-Effizienz des Resonators ist durch hohe Abstrahlverluste an die Umgebung relativ schlecht;
- die hohe Abstrahlung des Resonators beeinflusst störend andere in seiner Umgebung installierte Vorrichtung;
- die in der Umgebung des Resonators installierte Vorrichtung kann sich störend auf die Wirkungsweise des Resonators auswirken.
- The coupling efficiency of the resonator is relatively poor due to high radiation losses to the environment;
- the high radiation of the resonator interferes with other devices installed in its surroundings;
- the device installed in the vicinity of the resonator can interfere with the mode of operation of the resonator.
Es ist Aufgabe der vorliegenden Erfindung, ein Hochleistungs-Gyrotron der eingangs genannten Art anzugeben, das hinsichtlich seiner Auskopplungs-Effizienz verbessert ist, in geringerem Masse seine Umgebung störend beeinflusst und dessen Moden-Selektivität dennoch nicht wesentlich beeinträchtigt oder sogar besser ist.It is an object of the present invention to provide a high-performance gyrotron of the type mentioned at the outset, which is improved in terms of its coupling-out efficiency, has a less disruptive effect on its surroundings and whose mode selectivity is nevertheless not significantly impaired or is even better.
Diese sowie weitere Aufgaben werden gemäss der vorliegenden Erfindung gelöst durch die Angabe eines neuen Hochleistungs-Gyrotrons mit den Merkmalen des Patentanspruchs 1.According to the present invention, these and other objects are achieved by specifying a new high-performance gyrotron with the features of patent claim 1.
Die Vorteile der Erfindung sind im wesentlichen darin zu sehen, dass es gelungen ist, eine geschlossene Resonatorstruktur anzugeben, welche hinsichtlich ihren Moden-Selektivität mit der bekannten offenen Resonatorstruktur vergleichbar ist.The advantages of the invention can be seen essentially in the fact that it has been possible to specify a closed resonator structure which is comparable in terms of its mode selectivity to the known open resonator structure.
Die durch das erfindungsgemäss vorgesehene Gehäuse zusätzlich angeregten, sogenannten nichtgaus'schen Moden sind bezüglich ihrer Intensität gegenüber der oder den gewünschten gaus'schen TEMoop -Moden verhältnismässig schwach und tolerierbar.The so-called non-Gaussian modes additionally excited by the housing provided according to the invention are related their intensity is relatively weak and tolerable compared to the desired Gaussian TEM oop modes.
Durch die Erfindung wird die Auskopplungseffizienz auf 100 % erhöht.The coupling efficiency is increased to 100% by the invention.
Die Abstrahlung an die Umgebung wird durch das erfindungsgemäss vorgesehene Gehäuse praktisch vollständig verhindert. Andere Geräte, wie z.B. Ablenkspulen für den Elektronenstrahl oder ein Prebuncher können in unmittelbarer Nähe des Resonators aufgestellt werden.The radiation to the environment is practically completely prevented by the housing provided according to the invention. Other devices, such as Deflection coils for the electron beam or a prebuncher can be set up in the immediate vicinity of the resonator.
Vorteilhafte Ausgestaltungen der Erfindung sind in den abhängigen Patentansprüchen gekennzeichnet.Advantageous embodiments of the invention are characterized in the dependent claims.
Weitere Merkmale und Vorteile der vorliegenden Erfindung ergeben sich aus der nachstehenden ausführlichen Beschreibung insbesondere unter Berücksichtigung der beigefügten Zeichnungen. Es zeigen:
- Fig. 1
- in geschnittener Darstellung den Resonatorteil eines Hochleistungs-Gyrotrons nach der Erfindung in einem Gehäuse angeordnet und
- Fig. 2
- in schematisch-perspektivischer Darstellung eine vorteilhafte Geometrie der Hohlspiegel.
- Fig. 1
- arranged in a sectional view the resonator part of a high-performance gyrotron according to the invention in a housing and
- Fig. 2
- in a schematic-perspective representation of an advantageous geometry of the concave mirror.
Es wird nunmehr auf die Zeichnung Bezug genommen. In Fig. 1 sind mit 1 und 2 zwei Hohlspiegel bezeichnet, welche einander gegenüberliegend in einem Abstand d auf einer optischen Achse angeordnet sind. Die optische Achse fällt in Fig. 1 mit einer Koordinatenachse oder Richtung Y zusammen. Die beiden Hohlspiegel 1 und 2 bilden gemeinsam einen quasi-optischen Resonator.Reference is now made to the drawing. In Fig. 1, 1 and 2 denote two concave mirrors, which are arranged opposite one another at a distance d on an optical axis. The optical axis coincides with a coordinate axis or direction Y in FIG. 1. The two
Den quasi-optischen Resonator durchsetzt in der Mitte zwischen den beiden Hohlspiegeln 1, 2 ein Hochenergie-Elektronenstrahl 3 in Richtung einer Koordinatenachse Z senkrecht zur Richtung Y. Derart ausgerichtet ist auch ein in Fig. 1 nicht dargestelltes, weitgehend homogenes Magnetfeld zwischen den beiden Hohlspiegeln 1 und 2. Die Elektronen des Elektronenstrahls 3 bewegen sich auf spiralförmigen Bahnen um die Magnetfeldlinien. Dies ist durch die spiralförmige Linie in Fig. 1 angedeutet.A high-
Der quasi-optische Resonator von Fig. 1 ist in einem Gehäuse 4 angeordnet. Das Gehäuse 4 ist ein Zylinder, dessen Achse mit der optischen Achse der Hohlspiegel 1, 2 zusammenfällt. Es ist, wenigstens überwiegend, elektrisch leitfähig. Die Länge des Gehäuses erstreckt sich über etwas mehr als den Abstandsbereich d zwischen den Hohlspiegeln 1, 2. Das Verhältnis vom Durchmesser des Gehäuses 4 zum Durchmesser der Spiegel 1, 2 ist ein von der jeweiligen Anwendung abhängiger Parameter. Bei einem Resonator mit 2 % Diffraktionsverlusten gemäss einem Wert von ca. 1,4 für dieses Verhältnis, um die unerwünschten, nicht gaus'schen Moden zu unterdrücken. Gleiches gilt, falls die elektromagnetische Feldleistung nur an einem Ende ausgekoppelt wird. An seinen Enden weist das zylindrische Gehäuse 4 Anschlussflansche 4.1 auf. An die Anschlussflansche sind nur abschnittsweise dargestellte Mikrowellenleiter 5 angeflanscht. Ueber den Mikrowellenleiter 5 werden die im quasi-optischen Resonator erzeugten elektromagnetischen Wellen dem Ausgang des Gyrotrons zugeführt. Das Gehäuse 4 weist schliesslich noch Durchtrittsöffnungen 4.2 für den Elektronenstrahl 3 auf.The quasi-optical resonator of FIG. 1 is arranged in a
Durch das Gehäuse 4 wird die Abstrahlung von elektromagnetischer Strahlung in die Umgebung des quasi-optischen Resonators bzw. des Hochenergie-Gyrotrons praktisch vollständig verhindert und eine optimale Auskopplungs-Effizienz erreicht.Due to the
Durch den gewählten Radius des zylindrischen Gehäuses 4 und den dadurch sich ergebenden Abstand der Gehäusewand von den Hohlspiegeln 1 und 2 sind die durch das Vorhandensein des Gehäuses 4 zusätzlich angeregten nicht gaus'schen Moden gegenüber den gewünschten gaus'schen TEMoop -Moden tolerierbar klein.Due to the selected radius of the
Die erstrebte Modenreinheit lässt sich insbesondere dadurch verbessern, dass Hohlspiegel 1, 2 mit hohen negativen g-Faktoren bis zu -.8 verwendet werden. Der g-Faktor ist definiert durch g := 1-d/R, wobei d den gegenseitigen Abstand der Hohlspiegel 1 und 2 und R ihren Krümmungsradius bedeuten.The desired mode purity can be improved in particular by using
Weiter verbessern lässt sich die Modenreinheit durch selektive Dämpfung der unerwünschten, nichtgaus'schen Moden. Rechnungen zeigen, dass die stärksten dieser Moden vornehmlich in einem Abschnitt im Bereich der Mitte zwischen den beiden Hohlspiegeln 1, 2 an der inneren Wand des Gehäuses 4 einmal reflektiert werden. Durch Ausbildung zumindest der inneren Oberfläche des Gehäuses 4 in diesem Abschnitt in der Mitte zwischen den beiden Hohlspiegeln 1, 2 in einer elektromagnetische Wellen dämpfenden Weise, können demnach in einfacher Weise die unerwünschten nichtgaus'schen Moden selektiv unterdrückt werden.The mode purity can be further improved by selective damping of the undesirable, non-Gaussian modes. Calculations show that the strongest of these modes are primarily reflected once in a section in the region in the middle between the two
In Fig. 1 sind mehrere Möglichkeiten dargestellt, wie das Gehäuse 4 bzw. seine innere Oberfläche im genannten Abschnitt in der Mitte zwischen den beiden Hohlspiegeln 1, 2 ausgebildet werden kann. Es soll jedoch verstanden werden, dass jeweils nur eine der vier dargestellten Möglichkeiten tatsächlich verwendet wird. Die Möglichkeiten sind:
- Zur Erzielung einer Absorption kann die innere Oberfläche des Gehäuses 4 im genannten Abschnitt mit einer elektromagnetische Wellen gut absorbierenden Schicht 4.3 versehen sein. Die Absorptionsfähigkeit dieser Schicht sollte jedenfalls wesentlich grösser als die Absorptionsfähigkeit der Gehäusewand ausserhalb dieser Schicht sein. Alternativ kann die ganze Gehäusewand im genannten Abschnitt aus einem solchen Material bestehen, vgl. 4.4.
- Zur Erzielung eines Streuungseffektes kann die innere Oberfläche des Gehäuses 4 im genannten Abschnitt mit einer grösseren Rauhigkeit als ausserhalb dieses Abschnitts versehen sein, vgl. 4.5. Die Oberfläche könne auch gezahnt, profiliert oder in noch anderer Weise strukturiert sein.
- Die Gehäusewand kann im genannten Abschnitt auch mit Löchern oder Bohrungen 4.6 versehen sein.
- In order to achieve absorption, the inner surface of the
housing 4 can be provided with a layer 4.3 that absorbs electromagnetic waves well in the section mentioned. In any case, the absorption capacity of this layer should be significantly greater than the absorption capacity of the housing wall outside of this layer. Alternatively, the entire housing wall in the section mentioned can consist of such a material, cf. 4.4. - In order to achieve a scattering effect, the inner surface of the
housing 4 can have a larger one in the section mentioned Roughness should be provided outside this section, cf. 4.5. The surface can also be serrated, profiled or structured in some other way. - The housing wall can also be provided with holes or holes 4.6 in the section mentioned.
Die Ausdehnung D des genannten, in besonderer Weise ausgebildeten Abschnitts des Gehäuses 4 in Richtung Y der optischen Achse der beiden Hohlspiegel 1, 2 sollte sich vorzugsweise über maximal etwa 1/5 des Abstandsbereiches (d) zwischen den Hohlspiegeln erstrecken.The extension D of the named, specially designed section of the
Eine entscheidende Verbesserung der Modenreinheit kann schliesslich noch dadurch erzielt werden, dass Hohlspiegel 1, 2 verwendet werden, die eine stufige Struktur aufweisen, wie dies für den Hohlspiegel 1 in Fig. 1 beispielsweise dargestellt ist . Die Hohlspiegel sollten insbesondere zwei um ein oder mehrere ganz Vielfache der halben Wellenlänge der gewünschten Strahlung stufenförmig gegeneinander versetzte Spiegelflächen aufweisen. Die Radien der gegeneinander versetzten Spiegelflächen, in Fig. 1 mit r₁₁ und r₁₂ bezeichnet, sollten relativ zueinander so bemessen sein, dass auf alle Spiegelflächen der gleiche Energiefluss entfällt.A decisive improvement in the mode purity can finally be achieved by using
Zusätzlich zur Verbesserung der Modenreinheit könnten die vorgenannten Massnahmen auch zu einer Optimierung anderer Parameter, beispielsweise zu einer Verringerung des Radius r₄ des Gehäuses 4 dienen.In addition to improving the mode purity, the aforementioned measures could also be used to optimize other parameters, for example to reduce the radius r₄ of the
Durch Verwendung von Hohlspiegeln 1, 2 mit einer von der sphärischen Geometrie abweichenden Geometrie lässt sich der elektromagnetische Wirkungsgrad des Gyrotrons nach der Erfindung verbessern. Insbesondere sind Hohlspiegel von Vorteil, welche, wie in Fig. 2 beispielsweise dargestellt, in zwei zueinander senkrechten Richtungen X und Z unterschiedliche Krümmungsradien RX, RZ aufweisen. Die Richtung Z von Fig. 2 soll mit der Z-Richtung von Fig. 1 übereinstimmen.By using
Andererseits können die Hohlspiegel 1, 2 wie anhand des Hohlspiegels 2 in Fig. 1 beispielsweise dargestellt, in zwei Hälften in Z-Richtung unterschiedliche Krümmungsradien R₂₁, R₂₂ aufweisen.On the other hand, the
Claims (9)
- High-intensity gyrotron for generating electromagnetic millimetre or submillimetre waves, havinga) a quasi-optical resonator, which is formed by two concave reflectors (1, 2) arranged opposite one another on an optical axis, andb) a cylindrical housing (4), surrounding the resonator, which is at least partially electrically conductive,characterised in thatc) the axis of the housing coincides with the optical axis of the two concave reflectors
(1, 2), so that the emission of electromagnetic radiation into the environment of the quasi-optical resonator is virtually completely prevented and an optimum coupling-out efficiency is achieved. - High-intensity gyrotron according to Claim 1, characterised in that the wall of the housing (4) has a spacing from the optical axis of the two concave reflectors (1, 2) which corresponds to approximately 1.4 times the radius (r₁₁, r₂) of the concave reflector at the end of which the field power is coupled out.
- High-intensity gyrotron according to one of Claims 1 or 2, characterised in that the g-factors of the concave reflectors (1, 2) have negative values down to -.8.
- High-intensity gyrotron according to one of Claims 1 to 3, characterised in that the housing (4) in the direction of the optical axis of the two concave reflectors (1, 2) extends at least over the spacing range (d) between the concave reflectors.
- High-intensity gyrotron according to one of Claims 1 to 4, characterised in that a microwave conductor (5) can be connected to the housing (4) on at least one side in the direction of the optical axis of the two concave reflectors (1, 2).
- High-intensity gyrotron according to one of Claims 1 to 5, characterised in that the housing (4) is constructed in a section, which extends in the direction of the optical axis of the two concave reflectors (1, 2) and is arranged in the middle between the concave reflectors, in one of the following ways:- The inner surface of the said section is provided with a layer (4.3) of a material which absorbs electromagnetic waves more strongly than the material of the housing outside the said section;- the inner surface of the said section is profiled, for example in the form of a spherical indentation whose radius is a plurality of wavelengths, or is provided with a greater roughness than the surface of the housing (4) outside the said section;- holes (4.6) are provided in the housing wall in the said section.
- High-intensity gyrotron according to Claim 6, characterised in that the section extends over at most approximately 1/5 of the spacing range (d) between the concave reflectors (1, 2).
- High-intensity gyrotron according to one of Claims 1 to 7, characterised in that in order to favour the formation of a single, desired TEMoop mode, the concave reflectors (1, 2) each have at least two reflecting surfaces offset, step-wise with respect to one another, by one or a plurality of integral multiples of the half wavelength of the desired TEMoop mode and arranged concentrically with respect to one another, the surfaces of which are dimensioned relative to one another such that appproximately the same energy flux is incident on them.
- High-intensity gyrotron according to one of Claims 1 to 8, characterised in that the concave reflectors (1, 2) have a geometry departing from spherical geometry, which is characterised by two different radii of curvature (Rx, Rz) in two mutually perpendicular directions and/or in which the radii of curvature (R₂₁, R₂₂) in the direction of the magnetic field differ in two halves of the concave reflectors.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH79987 | 1987-03-03 | ||
| CH799/87 | 1987-03-03 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0281858A1 EP0281858A1 (en) | 1988-09-14 |
| EP0281858B1 true EP0281858B1 (en) | 1991-07-17 |
Family
ID=4195451
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP88102786A Expired - Lifetime EP0281858B1 (en) | 1987-03-03 | 1988-02-25 | High-power gyrotron for generating electromagnetic millimeter or submillimeter waves |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4926094A (en) |
| EP (1) | EP0281858B1 (en) |
| DE (1) | DE3863661D1 (en) |
| ES (1) | ES2023680B3 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0393485A1 (en) * | 1989-04-19 | 1990-10-24 | Asea Brown Boveri Ag | Quasi-optical gyrotron |
| CH678244A5 (en) * | 1989-06-23 | 1991-08-15 | Asea Brown Boveri | |
| JP2892151B2 (en) * | 1990-11-27 | 1999-05-17 | 日本原子力研究所 | Gyrotron device |
| US5450041A (en) * | 1994-09-19 | 1995-09-12 | The United States Of America As Represented By The Secretary Of The Army | Quasi-optical oscillator using ring-resonator feedback |
| US7507724B2 (en) * | 2001-01-16 | 2009-03-24 | Sloan-Kettering Institute For Cancer Research | Therapy-enhancing glucan |
| US7906492B2 (en) * | 2001-01-16 | 2011-03-15 | Sloan-Kettering Institute For Cancer Research | Therapy-enhancing glucan |
| US8323644B2 (en) * | 2006-01-17 | 2012-12-04 | Sloan-Kettering Institute For Cancer Research | Therapy-enhancing glucan |
| WO2008103363A1 (en) * | 2007-02-20 | 2008-08-28 | Wavestream Corporation | Energy focusing system for active denial apparatus |
| DE102009032759B4 (en) * | 2009-07-11 | 2011-12-15 | Karlsruher Institut für Technologie | Device for avoiding parasitic oscillations in cathode ray tubes |
| CN102956415B (en) * | 2011-08-29 | 2015-11-04 | 中国科学院电子学研究所 | A kind of method for designing of curved surface of reflector of gyrotron quasi-optical output system |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU497893A1 (en) * | 1973-02-27 | 1978-08-15 | Masalov S A | Diffractive radiation generator |
| US4491765A (en) * | 1982-09-02 | 1985-01-01 | The United States Of America As Represented By The Secretary Of The Navy | Quasioptical gyroklystron |
| US4531076A (en) * | 1982-12-02 | 1985-07-23 | The United States Of America As Represented By The Secretary Of The Army | Electron beam stimulated electromagnetic radiation generator |
| FR2542504B1 (en) * | 1983-03-11 | 1986-02-21 | Thomson Csf | RESONANT CAVITY FOR MICROWAVE, ESPECIALLY FOR ELECTROMAGNETIC ENERGY GENERATORS |
| FR2544128B1 (en) * | 1983-04-06 | 1985-06-14 | Thomson Csf | ELECTRON BEAM INJECTION DEVICE FOR RADIO WAVES GENERATOR FOR MICROWAVE |
| JPS603838A (en) * | 1983-06-22 | 1985-01-10 | Nec Corp | Cavity resonator for gyrotron |
| EP0141525B1 (en) * | 1983-09-30 | 1991-01-16 | Kabushiki Kaisha Toshiba | Gyrotron device |
| US4553068A (en) * | 1983-10-26 | 1985-11-12 | The United States Of America As Represented By The Secretary Of The Army | High power millimeter-wave source |
| JPS6113532A (en) * | 1984-06-28 | 1986-01-21 | Toshiba Corp | Gyrotron |
| US4559475A (en) * | 1984-07-12 | 1985-12-17 | The United States Of America As Represented By The Secretary Of The Navy | Quasi-optical harmonic gyrotron and gyroklystron |
| JPS61281702A (en) * | 1985-06-07 | 1986-12-12 | Hitachi Ltd | Device for extracting output of quasi-optical gyrotron |
-
1988
- 1988-02-25 EP EP88102786A patent/EP0281858B1/en not_active Expired - Lifetime
- 1988-02-25 ES ES88102786T patent/ES2023680B3/en not_active Expired - Lifetime
- 1988-02-25 DE DE8888102786T patent/DE3863661D1/en not_active Expired - Lifetime
- 1988-03-01 US US07/162,510 patent/US4926094A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0281858A1 (en) | 1988-09-14 |
| ES2023680B3 (en) | 1992-02-01 |
| DE3863661D1 (en) | 1991-08-22 |
| US4926094A (en) | 1990-05-15 |
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