DE2045103A1 - Electron discharge tubes - Google Patents

Description

DR. MDLLER-BORe D I PL-PHYS. DR.MAN ITZ DfPL-CHEM-D (LDEUFEL

DIPL-ING. FINSTERWALD DIPL-ING. GRAMKOW 2Q45103 PATENT LAWYERS

Munich, September 11, 1970 Hl / mü - -33 1025

MGLISiI EkSOIRIC YIiLW COMPANY LIMITED Bush House, Aldwych, London WC2 England.

El elct r onen-Jünt 1 adurig sr öhr e

The invention relates to an electron discharge tube and particularly relates to an electron tube of the type using so-called periodic magnetic field systems. Probably the best example of a tube of this type is the traveling wave tube.

The electrons from the cathode of a normal known Traveling wave tubes are driven by an electrostatic field accelerated, focused in an electron beam and eventually collected by a collector. For correct operation, the electron beam must necessarily be in a narrowly defined area around the axis or center line the pipes lie. Of course, if the electrons were left to their own devices, they would repel each other Spread it out to the side and make a proper tightening of the Beam would not be reached. Usually this is prevented by an axial magnetic focusing field that is generated by ring magnets that surround the casing or piston of the tube. Such a field can be through a simple tubular magnet system can be generated; it

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however, a large variation in the magnetic flux would be disadvantageous. From these. The focus is usually brought about by a periodic magnet system, which has a number of permanent magnets and pole pieces in an alternating polarity sequence (i.e. where adjacent magnets are provided in the opposite polarity order) along the axis, a typical known periodic magnet system of this nature is shown in Figure 1; therein is shown a portion of the Magnetsystens close a normally provided inlet or Ausgengswellenleiter Λ nit permanent magnet 2 and their pole pieces 3 .. A portion T of a support tube coaxially surrounds the EoIben of the tube, not shown.

In this arrangement, the waveguide (it can be either the input waveguide or the output r-waveguide) zx / ischen two of the Peraan ^ demagnets used, which due to its at a further distance from each other along the Axis of the tube than other adjacent magnets are arranged. Such an additional distance or space leads to a delay (hesitation) in the periodicity of the magnetic field, which is detrimental to the achievement correct focus. The effect on the beam depends largely on the current density of the beam, the mean velocity of the electrons of the beam and the relative dimensions of the waveguide and the Magnets off. In practice the waveguide dimension will be as far as in the direction parallel to the axis of the tube possible reduced »in order to keep the delay or interruption of the magnetic field as small as possible. This is a practical, satisfactory remedy in the! case of Tubes that are designed or intended for relatively low frequencies, because the tube dimensions of such tubes are relatively large and the disruptive effect due to the used The waveguide is small enough not to seriously interfere with the proper operation of the tube. However, this is not the case with high-frequency tubes,

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■ For example, tubes for operation at frequencies on the order of 6-GIIz oiler higher 'and at Power levelii below 25 watts $ the return period of the Focusing magnetic field system is small and that Input and output waveguides produce significant Interruptions adversely affecting the operation of the tube affect. Figure 2 shows the type of disturbance obtained in such cases; it is, as can be seen, a more striking area in the neighborhood of the waveguide used, where dan Iiagnetfelcl is under diminished control and to that tends to diverge from-the-axis (this area is in the rope of Fig. 2 Dargsetzt, the vertically below the representation of the waveguide in Fig. 1).

A known method of avoiding or reducing this adverse effect is to provide additional rod magic, which is positioned in a suitable manner near an inserted waveguide with its axes parallel to the pipe axis and its polarities opposite to those of the next neighboring solution ; The additional magnets are dimensioned and arranged in such a way that the irregularities in the space between magnets of the periodic system due to the waveguide used are compensated for. practical IT eight eil on, df; £ do. ε Hagiietsysten receives a considerably larger dimension in cross-section.

The aim of the invention is to eliminate or substantially reduce the disturbance of the fields .; a periodic agiiet system in a tube of the type mentioned - in particular a high-frequency traveling wave tube - without the disadvantageous effects of the known auxiliary cmi - ': when using -on additional magnets. introduce em.

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iJrriii'l ·: Ί; ; sgeiaäß wei ^r : '; -.ine jilektroncn-IJiitladungsrcL-re r.it einer ^ eriodisclioii Mngnetf eldGjsten. zuciiidcsv cii: P..ar VO .. bCuacLb types. Magneton with larger; Distance L:. "■;. Zv.dcclionrauJii in the amiden advises us that it is used zvjischcii 0 311 La» .iictCH ande 1 " ¹ Or of neighboring pairs, whereby the disturbance of the field is reduced or prevented due to the larger gap in which only one pole piece is provided, which is inserted between the two magnets which are located on each side of the larger space which is arranged adjacent to one of the magnets, so that the space between this pole piece and the other Magnet is released.

Preferably, two pole pieces are provided in addition to the inserted pole piece and each is adjacent to one or the other of the two magnets outside of them with respect to the outside. Space aiigeox'di.ot; In the case of the two pieces of the box preferably have an L-shape and extend with the line dec L ~ u β:; Zwi tc; ienrauia.

AdvantageLic.ftcrveise uix ^ d at the Auüi'ühruJi ^ der Ui'fi.iJa: ^ der Zwisclienraurii zur Aufiialime. oiiwr liinjr.Lgc- or Auo-

r-i v / ends.

The invention is illustrated in the following by way of example with the drawing becchriebon; in dicrcr shows:

Pig. Ί a part of a known periodic Magnet system,

Fig. 2 ei ... PcliaubildLches diagram, in doi.i Hie nacliteilige effect of an inserted wave loiter ρ auJ "the τ-. · -Ι '-A - j τ-, r. -, -, / in a Γ ; ri; nt r.vr-tor "periodicity of magnetic fields ,, is shown ¹ , Fir

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! '"Fig. 3 is a diagrammatic partial sectional view of a ■ Inventive magnet assembly edge

Pig. 4- a diagrammatic diagram similar to Fig. 2 » in which the beneficial effect of the disapproval Magnet arrangement on the periodicity is shown.

After FIG. 3, which is a view similar to that in FIG. 1, showing a known arrangement, the periodic magnet system comprises alternately polarized periiianerite king magnets 2 which are separated from one another by pole pieces 3? ^L V and 5 are separate. Only part of the periodic magnet system is shown and the pole pieces (except where input and output waveguides are used) have a tapered T-cross section, ie a cross section similar to that of pole piece 3 - or an output waveguide of a traveling wave tube - is used, the magnets 2 have on both sides a larger distance or gap in the longitudinal direction than is generally provided over the periodic system. In a known arrangement, as shown in Fig. 1. X'TÜrde this lead to the disturbance of the field, as it is shown in FIG. In contrast, in the embodiment of FIG. 3, an asymmetrical arrangement is provided on each side of the waveguide used, the asymmetry being selected in order to compensate for the disturbance which would otherwise occur. The asymmetry is achieved in the embodiment shown in Fig. 3 by a pole piece only on one side of the waveguide 1 between the waveguide and the magnet 2 on one side, but no pole piece on the other side of the waveguide between this and the next magnet 2 is provided on this page. This one pole piece is the ESL piece 5

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It is almost ring-shaped, but has a small "step ¹ , ¹ as shown, in order to localize the waveguide 1. The next outer pole pieces - the pole pieces ^L Y - also have an L-cross section and are connected to the base of the L directed towards the gap where the waveguide is inserted. The actual dimensions to ensure minimal interference can be chosen according to known principles; however in practice it is likely to be easy to complete a construction by trial and error. By means of a suitable construction it is possible to to achieve a fairly close approximation of perturbation zero as graphically illustrated ^{in E 1 Xg.}

In practice, the L-shaped pole piece 4 can be on the same Side of the waveguide 1 like the pole piece 5 through a Pole piece with inverted T-shape (similar to pole piece 3) · but with less heating of the focus, - exchanged will.

OTqgjLeich the main field of application of the invention traveling wave tubes are, it is with anö. > Ren ears of the type mentioned in particular applicable to klystrons'.

Patent claims

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Claims (2)

P ate η t · a n s ρ r ü C * .i e MJ Klektron discharge tube with a permanent magnet system, which knows at least one pair of neighboring magnets with a greater spatial distance or space in the axial direction than it is used between the magnets of other pairs of lneiiaclf.iartc-r, thereby geke η η ζ eich η et that only one piece (5) is inserted between the two Iiagnete (2), one of which is on each side of the larger space, and that the PoI-Gtüch (/ ■) mijx-encend toi 'is arranged a dc-r- HaGiiete (2), so J:? u · ( ^"1 Cr Zv ischcnran ^r.:. svischoii the löLstücli (^) and do.u, aideren Iiagnet (2 gelaeecn -i), whereby the Störun _w of the field decreases due to the larger "wischenrauinee or is prevented. ' 2. Höhre no.ch claim Ί, thereby ge 1: e η η ζ eic .-. net, since £ -: 3 two pole pieces additionally: u the inserted pole piece are provided so that each pole piece adjoins one or the other. other of the n ^v ; a neck is arranged outside of this with respect to their interspace, and that the two pole pieces have an L-cross-section and extend with the base of the L to the interspace. 3 tube, inch j \ nspruch Λ or 2, thereby: gek en η - ζ e i c line t that the gap for inclusion a 3input or output waveguide is used will. ¹ Vc Use of the magnetic field system according to one of claims 1 - J in traveling wave tubes, klystrons or other tubes of the type in question. 109813/1 ς 18 BAD ORIGINAU