DE1514490A1 - Electron beam generation system for electrical discharge vessels - Google Patents

Description

Ί514490 ^β

Mije Ό <ιΐ? Ι

SIEtIMiS AKTIMGESELLuOHAi ¹ T ge.

WtilBerplatz 2
PA 65/2484

Electron beam generation system for electrical de- " O ΰ ftäWale Jef äßü 1Ί il D 8 8 § fl II g 91 il 9 ί IU ©

The invention t ^ r ^ ffe e ^ n ^ gj ^ generating system for elec- _@ trisclie discharge vessels, in particular power tubes, "in which the S tr aiii electron-emitting! Cathode; * (beam system cathode)
for their heating with their soil the ElektrÖli'enätiip ^ Öli ^
I plane for one axially in the opposite direction of the beam
arranged auxiliary electron discharge path MMe ^ -whose @ indirectly heated auxiliary cathode as a supply skatho de m £ t " ^{: I} @ frontal emission surface is formed.

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It has. "More meaning for with electron beams working high-performance tubes. For this type of tube,

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For example, for traveling wave tubes with high power, there is a major difficulty in locating the electrodes, which are required for beam shaping and are especially in the immediate vicinity of the cathode, keep so cool that they are also with steam

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Emission-demanding substances do not emit thermal emissions. This keeping cool requires measures by which the amount of heat given off by the cathode is as small as possible. For a given cathode temperature _(this depends? Amount of heat given BZV /. _R of the adjacent control electrode 8μίgenommene amount of heat from the size of .the surface of the respective cathode, with regard to the success heat radiation and vpn der_durch, the inevitable mechanical connections related to the holders Y / ärmeleitung , away.

But with the demands _{to be expected in the future and above all T} , the specific, emission of a

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Cathode must be _r ^ ie_Kathode temperature. increased to over 1100 ° who _; de ^ _T ^ ... g ^^ i ^ Ayt ^ a ^ Jath ^ ode to heat,.

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consists in that it is provided with a heater which generates the required heat by passing an electric current, but certain requirements must be placed on the heater. If it is in the immediate vicinity of the cathode surface, it should not generate any alternating magnetic field and thus no hum. The current conduction must therefore be as bifilar as possible * and the heating current intensity must be kept as low as possible accordingly. A heater made of appropriately thin wire that meets this requirement has little heat dissipation, but because of the insufficient stability corresponding to its low mechanical stability, it cannot be designed and arranged in a self-supporting manner over a long service life. It is therefore necessary to insulate it for support, the insulation being in contact with the actual cathode, so that it must withstand a certain electrical voltage between the heater and the cathode. The quality of this insulation depends, among other things, on the level of the heating temperature. In order to keep this as low as possible, the entire interior of the cathode is often filled with insulating compound, i.e. the heating coil is cemented into the heater room in order to use the heat conduction of the insulating compound in question to create the actual

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supply a lot of heat to the cathode. This type of heater design has the advantage that it is associated with relatively little heat loss. However, a considerable space is required to accommodate the heater, which corresponds to a cathode body of a much larger size than the part required for the emission. The heat to be generated is therefore a multiple of the amount of heat actually required for the emission, so that an unnecessarily large amount of heat is supplied to the critical electrodes. In addition, the problem of insulation is already beginning to become critical with this so-called cemented heater. The occurrence of electrolysis within the insulation material - to name one of the possible interfering phenomena - does not depend on the temperature directly but exponentially, so that a necessary increase in cathode temperature of 20 ° can already have a very disadvantageous effect such that, for example, the insulation via a guarantees long service life ^r is not controlled more surely.

The task on which the registration is based is therefore the size and thus the surface to make a beam system cathode as small as possible through special constructive hatreds and thereby

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at the same time the disadvantages of the previously described Avoid conventional constructions of such systems, thereby reducing the temperature of the radiant cathode directly surrounding the relevant beam shaping electrode to keep it as cool as possible so that it is also steamed with emission-promoting substances cannot cause thermal emissions during operation.

This is achieved in a beam generation system for electrical discharge vessels according to the invention described in the first paragraph in that the beam system cathode is designed as a supply cathode, in particular as an MK cathode, with a porous *; Bmissionsstoffträgererscheibe M closes a storage container filled with storage substance of low cylindrical shape and is the only cathode delivering beam electrons, and that the auxiliary cathode of cylindrical shape has a smaller diameter than the beam cathode (main cathode).

The radiation system cathode is designed without a heater and thus consists only of the emission surface which forms the emission surface and that of it Covered emission material storage container, which, as a working electrode, receives its required heat input through electron impact received from an auxiliary discharge. As a result, the actual cathode can be kept very small, so that ™

thereby, advantageously also those in the vicinity of the heat-critical electrode generated heat a particularly! your amount can absorb.

The cathode required for the auxiliary discharge is thus a storage cathode, in particular a metal capillary cathode formed, which also has a frontal emission material carrier and, when heated, a corresponding one

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usual heater is used. However, this is also much further away from the relevant heat-critical electrode and its heat is therefore negligible. The auxiliary cathode. form as a dispenser cathode, has been known from a Slektronenstrahlsystem forth plated cup- or in which two or flour ¹ laifc emission substance within a radiation protective cylinder pot-shaped hollow body perpendicular to the beam direction behind the other are arranged between which electron-optical Eelder form, the diue electrons to the opening Concentrate of the following hollow body, the openings being braced by hatches covered with immission-3übstanz and only the first hollow body, which is heated by a heater, is due to 'a double floor like a storage container e.Lufxi' covered by a porous floor and filled with storage substance Has.

The main disadvantage of this known arrangement is that the beam electrons from more expensive Emission areas with different potentials be amazed;., therefore have different speeds and are very difficult to control and focus.

a reliable shielding of the discharge of the auxiliary system from the main system is L · :. The thermal insulation membrane, which is used to hold the main cathode, consists of a lantalum foil cylinder and is coaxially provided with a tubular pulling anode for the auxiliary system, which is provided with one or more diaphragms. arranged. In a particularly advantageous ^r u ^r else is at least one of these apertures with G et berme tall, ζ. 13 * Sirkon verceliiii un-ü ¹ -whose opening is dimensioned so that it is of the

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electron discharge is sufficiently heated by impact. Because the auxiliary discharge with If the current density is relatively high, it also functions at least partially as an ionization path, see above that in connection with the getterable aperture diaphragm an effective ion getter pump is formed. In advantageous Further development of the beam generation system is the respective thermal voltage generated by the cathode carrier Thermoelectric transition point formed from molybdenum and tantalum foil cylinders during operation is generated, to control the discharge current strength directly or correspondingly amplified the Wehnelt electrode and thus the emission temperature of the main cathode is controlled in such a way that, for example, an automatically working temperature control can be achieved.

Further details of the invention should be based on the embodiment example shown purely schematically in the figure of a beam generation sys- tem will be explained. Parts that are not essential to understanding the Invention are omitted or unmarked.

In the figure, 1 is the heat-critical beam forming electrode of the beam generating system,

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the beam system cathode is formed in its aperture as a supply cathode, in particular as an MK cathode 2.3 is located. It essentially consists of the emission material carrier disk that forms the emission surface 2 and the supply covered by it. container 3. It has no usual heater, so your Cathode body, in particular storage container, can be designed as a very flat cylinder. Your surface is therefore kept very small, so that at this point also the one that is decisive for the beam-shaping electrode Heat conversion is a minimum. The cathode carrier is held by a radiation protection jacket made of a tantalum foil cylinder 4, which is directly below the emission material carrier disc 2 on Cathode body 3 is attached and can still be surrounded by a further radiation protection cylinder 11. The heat is supplied by electron impact from an auxiliary electron discharge, which is essentially generated within the radiation protection jacket 4 with a coaxially arranged auxiliary discharge system will. For this purpose there is coaxial inside the radiation protection cylinder 4 a tubular first tension anode 5 provided with one or more diaphragms 6, 7 is provided and in front of this an auxiliary cathode 8 designed as a supply cathode ^ in particular as an MK cathode with heater 9 and corresponding Wehnelt cylinder electrode

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arranged. When operating the beam generating system shown there is initially an electron flow from the heated cathode 8, which flows through the pulling anode 5 is accelerated with their diaphragms 6 and 7 towards the main cathode 2, 3 and with a relatively high discharge density he follows. In that a diaphragm, in particular that arranged in the interior of the tubular electrode Aperture 7, covered with a getterable metal, such as zirconium, titanium or the like, can from this the residual gases ionized in the discharge path are gettered. For this purpose, the Aperture opening selected to be smaller than that of the input diaphragm, so that occurring after the aperture type Electron impact one for the (jetting process sufficient heating occurs. It is within the scope of the inventive measure when the relevant discharge vessel to lead and control the discharge so that a sufficient Pumping effect is achieved without a significant heating of the cathode itself takes place. Of course can continuously be in operation with the ionization section and gettering device formed in this way emitting main cathode, a pumping action that ensures a high, good vacuum can be achieved. About that In addition, the connection between the cathode body made of molybdenum and the shielding cylinder made of tantalum is immediate

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below the porous emission material carrier disc a thermoelectric transition point created, so that the thermal voltage generated on it in operation to regulate the emission temperature can be used. For this purpose, of the two mentioned are the actual ones Parts representing metal conductors namely storage container 3 and shielding cylinder 4 at least up to one enough cold spot made from the same metal. The generated thermo-voltage is immediate or correspondingly increased to the Wehnelt cylinder dea auxiliary discharge system and thereby supplied via the Discharge amperage determines the emission temperature or is automatically regulated.

9 claims
1 figure

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Claims (3)

α "isT" sfö = 1968 SIEHEITS AKTIENGESELLSCHAFT 8 Munich 2 Witteisbacherplatz 2 1. Beam generation system for electrical discharge vessels, in particular power tubes, in which the beam electrons emitting cathode? * (, beam system cathode) to their Heating the electron impact surface with its bottom forms for an auxiliary electron discharge path arranged axially in the opposite beam direction, whose indirectly heated auxiliary cathode is designed as a supply cathode with an emission surface at the end, thereby characterized in that the beam system cathode is designed as a supply cathode, in particular as an MK cathode, with a porous, emission material carrier disc a storage container filled with storage substance τοη lower cylindrical Form completes and is the only cathode delivering beam electrons, and that the auxiliary cathode τοη more cylindrical Shape has a smaller diameter than the beam cathode (main cathode). 2. beam ore generation system according to claim 1, characterized in that that the beam system cathode (2,3) from a directly below the porous emission material carrier - 2 909826/0550 ■ zx:. 4.9.tV · * ·· Disc-fastened Tontal-Poliensylindor (4) held, in dosaoa interior coaxially <- <ino tubular with an odor nohreron aporture screens spare vorsugavreiod auoa nua a foil cylinder existing electrode (5) ale zu ^ nnoda and eur shielding for dae discharge foyetea against dna main tetras Erseusungaeystem arranged let * 3. strahlerseugunsasyetea after / nopraclöii and 2, characterized gokennsoieiiaot "that of dor sua auxiliary Elektronenontlftduncooyotoa gohiJrondcn rohriüruigon u ^ ^^ node (5) from ühnlioh vorisuijsweiee Molylidilr" the interior la ^ nn eorclnote Aporturblondo (7) old Zirfront Tltpn or einou well-sealed metal covered or auo dioaea wosontlioh lot and for cino S & ro £ auia. "i: aQ sur sun * gettern r ^ irLiimc (Larzh 21o3: trononaufprall a kleitttre opening never dio atirnooitlse Bintrittsblendo (6) has. 4 · Strahlerisoujungeeyatem claim characterized 3t · ^ ekenn- ;, eeichiiat that of the Aporturblcir ^ o (7) Bleohatörk · zua edge, ellnC ^ preferably UICH, oV.::irat. 5 ·; '- trrihlersou £ jun £ 3ayatea after tinom or xziohroron the v; rri: i ^ ohond ^ ii ^A Jioprüohe _# daduroh coIrojansoioJinot that dft « $ --- ahloystem-cathode (2,3) alt iiraa Polionhalterungosylindor (4 ) of a further coaxial PoIion ^ yIInder (11) sur orhUhton thermiaohen Atosohifcnung 'uneven plumb bob. BAD ORIGINAL 9 0 9 8 2 6/0550 15H490 β. Method for operating an indirectly heated, electron beam generating *. Storage cathode according to the preceding claims 1 to 5 »characterized in that a high-density auxiliary electron discharge sufficient for heating the beam cathode (2, 2) is generated specified cathode temperature is controlled and for the control voltage acting on the Wehnelt cylinder of the auxiliary cathode, preferably that thermal voltage is direct or corresponding % Increased use is made of the from the cathode support (5) made of molybdenum and radiation protection jacket (11) made of Eantal thermoelectric formed by the beam system cathode Transition point is created * 7 · Method according to one vein more of the preceding claims, characterized in that the _f extending from the Hilfokathode auxiliary electron discharge zummindest partly as lonisierungsstreokö for an ion getter pump is λ, and preferably takes place in the region of saturation. ORIGINAL Blank page