DE2142869A1 - Time-of-flight tube with delay line made of coupled cavities - Google Patents

Description

V1 P300 D

VARIAN Associates Palo Alto, California »USA

Time-of-flight tube with delay line made of coupled cavities

Addendum to patent. ·. (Patent application P 21 39 424.1) Priority September 8, 1970 USA Ser. No. 70 197

The main patent relates to a transit time tube with a delay line made up of coupled cavities »of which each neighboring have a common end wall» in each of which one Number of generally radially directed »elongated inductive coupling slots provided 1st» and the specialty of the The main patent consists in the fact that between the end walls of the delay line there are devices with which the flow of electrons along a secondary beam path parallel to the main beam path through at least one radial inner part of each of the coupling slots is interrupted »

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Various devices for interrupting the secondary beam path are proposed in the main patent The object of the invention is to provide a further device for interrupting a secondary beam path in things that are particularly cheap in terms of production technology,

According to the invention, this object is achieved in that ν / ε-at least one of the coupling slots in one end wall is at least partially closed · With such a con ~ In the construction, all end walls used can be produced in essentially the same way; it is sufficient if a single one of the coupling slots in a row of the end walls is only partially or not at all cut out.

In each case one of the coupling slots is expedient not cut out at all, so that aic N rows of coupling slots have a number of end walls in each case less than N slots, in particular javeils N-1 slots.

Known tubes have eight rows of coupling slots, and such a tube is modified according to the invention in such a way that that eight of the end walls each have seven slots which are offset from one another by η · 45 °, wobsi η is an integer.

A transit time tube according to the invention is particularly advantageous in which each cavity is in the manner of a clover-leaf line has four conductive, inwardly projecting lugs which are offset from one another by 90 °, and dia Turf in consecutive cavities at 45 ° against the / lasers are offset in adjacent cavities.

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The invention is to be explained in more detail with reference to the drawing will; show it

1 shows an acheaatic longitudinal section through a known microwave oven

Fig. 2 is a section along line 2-2 in Fig. 1;

Fig. 3, the output power as a function of time for Yftr e r ^ ng hf * ¹ ^ 1 C) IIT ¹ T g of Spannungsver- run for a Auegangeimpuie Auegang on the tube of FIG. 1 |

Fig. 4 is an exploded side view of the in Fig. 1 old the line 4-4 enclosed part, but modified according to the invention; and

Fig. 5 Sections along lines 5A-5A to 5H-5H.

In Flg. 1 shows a known microvial transit time meter 1, which is to be improved according to the invention. The microwave tube 1 shown has an electron beam generating system 2 with which an electron beam 3 is projected over an elongated beam path to a beam collector 4. Along the beam path between the system 2 and the collector 4 there is a cloverleaf delay line 5 made of coupled cavities, which interacts electromagnetically with the beam in order to generate an amplified output signal. A beam focusing coil 6 is arranged coaxially to the delay line 5 in order to generate an axially directed Kafnetfeld in the beam path 3 with which the electron beam is focused through the delay line 5 to the collector 4.

Bio delay line 5 has a number of axially aligned, coupled trefoil cavity resonators 7,

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which are sequentially arranged along the beam path for cumulative electromagnetic interaction with the beam are. Each cloverleaf cavity 7 has two axially spaced apart band walls 8 and one protruding inward bent side wall on "so that four conductive lugs 9 are formed" at intervals of 45 ° around the beam path protrude inward around the beam axis (see Fig. 2). Adjacent cavity resonators 7 share a common end wall 8. The inwardly protruding lugs 9 in adjacent cavity resonators 7 are angularly offset from one another by 45 ° around the beam path.

Two radially directed elongated inductive coupling slots 11 are arranged on both sides of the lugs 9 (cf. FIG. 5) in order to obtain a negative mutual inductive coupling between adjacent cavity resonators 7. The coupling slots 11 are designed to be radially elongated in order to increase the inductive coupling between adjacent cavities. In the known agitator, the inductive coupling slots 11 are aligned axially along a path parallel to the beam path, and the eight rows of coupling slots were arranged around the beam path 3 at intervals of 45 °.

Vibration energy to be amplified is fed to the jet-warm cavity 7 via an input waveguide 12, Over which a wave-permeable, vacuum-tight window 13 is used to maintain a vacuum in the evacuated Ilikrowellenleltung 5. On the longitudinal center the delay line 5 of coupled cavities, the line has a line separator 14, which consists of a solid, conductive disk with a central opening, the has no coupling slots in order to establish an oscillation energy communication between the upstream part 15 of the

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Delay line and the downstream part 16 To prevent delay line. The disk 14 has a central opening in order to enable the electron beam 3 to pass through. Vibration damping elements 19 and 20 are connected to the downstream cavity 7 of the upstream conduit part and the upstream cavity of the downstream portion 16 coupled »to absorb vibrational energy on opposite sides of the separator 14 is coupled into the cavities.

In the beam upstream delay line part 15, the calls The microwave energy supplied to the upstream cavity produces an oscillation on the line that is cumulative interacts with the beam in order to focus it · The focused beam runs from the upstream beam Line part 15 to the downstream part 16 in order to increase vibration in the downstream line part 16 to create. The oscillation in the downstream part 16 interacts cumulatively with the bundled beam, so that a growing oscillation in the downstream line part 16 is generated. Output visual vibration energy is removed from the downstream end of the downstream line »part 16 via an output waveguide 17, the with a vibration-permeable, gas-tight window 18 is locked. The removed from the waveguide 17, high » Frequent output energy is fed to a suitable load, not shown.

If in the known tube the output power was greater than 1 MW peak power, and the pulses a Had durations greater than 10 microseconds, the Peak output power suddenly drops to about half the peak power in the second half of the pulse length (Fig. 3).

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It has been found that this drop in performance arcs in the output line part 16 was assigned · «In particular, it was found that undesired electrical« nen partial rays through the axially aligned rsilien were accelerated by coupling slots and the end walls of the first and last cavity in the downstream power section 16 bombed.

When the output power is a relatively high level sr ~ F was on the order of 1 MV /, and the pulse length was on the order of 10 microseconds or more, it was found that the energy in the partial beams was sufficient to penetrate parts of the end walls of the end cavities " melt * When the cavity end wall was melted, trapped gas was released, creating an arc arose in the tube, which ensured that the output power dropped to about half the value.

It has been found that arcing can be prevented and the efficiency of the microwaves noticeably increased if the flow of electrons in the partial beams is interrupted, for example by blocking a line of sight path parallel to the beam through each of the rows of coupling slits so that the partial beams move do not shape so far that they cumulatively interact with the oscillation on delay line 5. An advantageous arrangement according to the invention for blocking the individual partial beams is shown in FIGS.

In Figures 4 and 5 , the angular orientation of the successive cavity resonators 7 about the beam axis 3 together with the relative angular orientation of the slotted common end walls 8 between the

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Cavities shown. Each of the protected band walls 6 may only have seven of the eight inductive coupling slots 11 on. The seven slots 11 are axially aligned with the eight rows of slots, that is, at 45 ° each Slots are provided spaced around the beam axis, except that one of the slots in each of the end walls δ is omitted is. Between the first and the seventh slot there is therefore a part that is not provided with an opening in each of the end walls 8 the end wall present »corresponding to the missing slot, as indicated at 22 ·

The successive cavities 7 are stacked to the longitudinal arrangement so that the lugs 9 in adjacent resonators angularly relative to one another by 45 ° are offset around the beam axis 3. The cavities 7 and the end walls 8 are arranged on eight alignment rods, the through openings 23 in the outer edge of the cavity resonators 7 and end walls 8 are provided. In this catfish one becomes precise angular alignment of the successive cavities 7 and end walls 6 is obtained.

In a sequence of eight cavity resonators 7, the common end walls 8 are identical, but the angular position of the missing slot 22 is opposite to the other end walls offset in the set of eight end walls such that the missing slot 22 has each of the eight possible positions corresponding to the eight angular positions of the individual axial rows of coupling slots 11 so that effectively a line of sight path through each of the eight axial rows of coupling slots 11 is blocked. In a particularly expedient arrangement, the angular position of the missing slot progresses 22 across the axis of the beam by 45 ° in successive resonators 7, viewed in the direction of the beam

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through the longitudinal arrangement of resonators 7- In this way If the missing slot proceeds in a spiral-like manner through the series of resonators 7.

It is desirable that the number of missing slots 22 per resonator be minimized, about one lack of slot 22 per end wall 8 to make the inductive coupling between successive resonators as close as possible · In the preferred embodiment * with a cavity arrangement coupled with eight slots there are seven slots 11 in each of the common End walls δ provided »as shown in Figures 4 and 5 1st. However, it is possible in certain application cases to provide more than one missing slot 22 per common end wall 8, if this also reduces the inductive coupling between adjacent resonators 7 *

The arrangement shown in FIGS. 4 and 5 for blocking the partial beams by the delay line 5 coupled cavities is particularly advantageous because all end walls 8 are identical and only in different Angular positions are mounted to form the composite delay line 5 from coupled cavities.

An examination of the melt pattern, which is caused by the individual partial beams in the known tube according to Flg. 1 on the End wall of the last cavity according to Flg. 2 was generated that the melting process was generated coinciding with the radially inner third of the slot length, seen in the radial direction. The missing · slot 22 needs so not to be completely absent, it is sufficient if In one other embodiment if about the inner half of the Slot 11 is blocked because the bite is missing. The missing one

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Slit can therefore be partially present *

If one moves along the delay line 5 from the downstream Moving the end to the upstream end, the intensity of the electric fields of the Oscillation »The requirement to block the individual rows of coupling slots is reduced accordingly. The partial beam blocking device can therefore in the Near the end of the delay line 5 upstream of the beam "can be" omitted "approximately in the upstream line part 15

In certain hybrid conduit tubes (for example as described in U.S. Patent 3,289,032) the beam upward portion 15 of the delay line 5 is sequenced replaced by klystron-like entrance cavities. In such a tube, the downstream line position 16 is used as an output circle. The partial beam blocking devices according to the invention are expediently used to increase efficiency and arc formation in one to prevent such a hybrid tube

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Claims (5)

V1 P300 D claims 1. Time-of-flight tube with delay line coupled out Cavities, each of which is adjacent one common End wall each having a number of generally radially directed, elongated inductive Kojspelschlitzen is provided, in which between the ends of the delay line devices are arranged with which the FIuB of electrons along a secondary beam path parallel to the main beam path through at least one radially interior Part of each of the coupling slots is interrupted, according to patent ··· (patent application P 21 39 424.1), characterized in that at least one of the coupling slots in an end wall is at least partially closed 1st · 2nd run tent tube according to claim 1 having N rows of coupling slots, characterized in _t that a number of end walls each having less than N slots. 3. Time-of-flight tube according to claim 2, characterized in that at least N end v & nde each N-1 Have slots 4. transit time tube according to claim 3 with eight rows of coupling slots, characterized in that 209812/0995 2U2869 .4 *. uwv - :; zr? dL eight end walls each have seven slots that around η · 45 ° are offset from one another «where η is a whole Number 1st. 5. Time tube according to claim 4 »characterized» that each hollow space »has four conductive» inwardly projecting Kazan »which u» are offset by 90 ° »and the rabbits in successive Cavities are offset by 45 ° from the noses in adjacent cavities 209812/099 * 5