DE1491358A1 - Device for phase focusing of charged particles - Google Patents

Description

1491355

DR. ING. ERNST MAIER PATENT Attorney

MUNICH 22

WIDENMAYER8TB.4. TELEPHONE 222530

17 JAR 1964

A 764

Company KABUSHIKI KAISHA HITACHI SETSAKtJSHO, 4, 1-Ohorne,

Marunouchi, Chiyoda-Ku, Tokyo-To / Japan "

Device sur live focusing of charged

Particle (klystron)

The invention relates to devices for phase focusing with sea velocity modulation for use in one part of a disruptor of high-energy charged particles, such as an electron linear accelerator. In particular, the invention is directed to a device for phase focusing charged particles of miniature size with particularly advantageous features.

In general, the conventional devices for Phase focusing with speed modulation from the Art, with «eloher a speed modulation in

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Sparfciue Sdirombera Bankhaut Paul Kapff, Slutteart PoiUdiedc. Stuitaart 73291 Möndien 153841 Telegram tresie. Pafents »nTiP"' ^- '

U91358

concentrated way with the help of a control column an oil-charged particle is communicated, which one Phase focusing using a field-free space which is usually called a transit time tube or »drift tube is referred to, and also of the type in which high-frequency, electromagnetic l / ellen, the one Speed modulation in an essentially continuous V / eise in a certain orbit interval el- ^ communicate with a beam of charged particles, are provided and at the same time a phase focusing is effected

The invention provides the same effective results when applied to either of the above two cases, however If the following description to explain the invention is mainly based on the first-mentioned design the device directed. Furthermore, although a multitude of combinations, each of which has a tax gap and a drift tube along the path of the charged particles can be placed, the case of two such Combinations that are considered easy to implement and at the same time have a relatively high degree of efficiency results, shown in the accompanying drawings. Also, while ea is possible, different types of loaded skins and various types of acceleration devices to use, to explain the case of a tin electron linear accelerator described «

■■■ '■'"^;---.''- O <Hä 909811/0938 BAOORIGiNAL

The object of the invention let the Sohaffung a device but Phasenfokusaierung of charged Teilohen of relatively simple Bauari and miniature size with respect dee space requirement and efficiency is advantageous.

Can be a further object of the invention is the Sohaffung a device of the type mentioned which effectively used for a wide scope "earth" g

The object of the invention is therefore essentially a device for phase focusing of charged particles with a source of charged parts, a high-voltage pulse transformer through which the charged parts are directed from the particle source in a path, and a device for phase focusing the charged parts in this way is delivered from a source via a coaxial cable from the high-frequency Srregerweilen, with the device according to the invention essentially differs in that a part or the whole high frequency f 3rre & erwellenenergie which is wound around the Hoohepannunga-lmpulsUbertrager.

The essence, principles, and details of the invention

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result from the following description for the case in which electrons are used as charged particles. are »In connection with the accompanying drawings, in which like parts have the same reference numerals are designated, namely show:

1 shows a simplified circuit diagram for describing the working principle of the invention Device and

Flg. 2 a circuit diagram, partly in block form »which shows the composition and arrangement of a preferred embodiment of the invention.

As is apparent from Fig. 1, an electron beam 1 is emitted by a beam generator, the housing having 5a designates 1st "The electron beam passes successively through a first cavity 3 _t a first drift tube 9, a second cavity 10 and a second drift tube 11 therethrough. The following designations have been chosen for the various Qröüen of this device. The electrons are injected with an injection voltage Vo and an injection velocity V _00. The first cavity 8 has a coupling gap G ₁ in which a high-frequency voltage with the amplitude V _{1 is} excited, while the second cavity has a coupling gap G ₂ ^nat " ⁱⁿ which a high-frequency voltage with the amplitude V"

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is excited. The gap G ₁ has a center point P and a gap coupling coefficient ^ ₁ , while the gap G _{2 has} a center point P ₁ and a gap coupling coefficient ?? ₂ has phase focusing or agglomeration should take place _{at a point P 2.} Points P and P ₁ are separated from each other by a distance I ₁ , while points P ₁ and P _{2 are} separated by a distance Ig.

The _{conglomeration X 1} for the first cavity 8 and the ball lunganaß X ₂ for the swelten cavity 10 is then given by the following equations

whereby:

Eat

C is the speed of light;

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2lf .χ ψΐ- and

βο

i _Q2 ~ they t χ ^ -i

where f is the frequency of the high frequency exciter wave.

For the choice of the values of X ₁ , Xg t V ₁ and Vg was made in the Japanese patent ···· .. ···. · (Japanese patent application 10 636/1962), according to which the choice corresponding to ^ - ^ p · ■■ 0.1 ρ X _1. * T £ * Xg * ~ 2 ~ ^ ¹¹¹¹¹ others

^f 2 conditions is close to the optimum and it is possible at point P about 90 $ of the electrons supplied by the beam generator within £ 0.1Tt radians in the vicinity of a certain phase angle

In most of the electron linear accelerators, the mean electron velocity v _{# 0} at the entrance of the Beaoh accelerating tube (the position Pg shown in FIG Economics. Accordingly, in the case where the electrons are injected at a speed of 0.5 C from the gun 3, the corresponding one can be used

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- 7 injection voltage can be regarded as V ₀ * 80 KV.

On the one hand, the values of the amplitudes V ₁ and V _{2 are} chosen to suit the condition

^ 0.3V

It is satisfactory to achieve effective velocity modulation and also to prevent the electrons at point F ₂ from experiencing excessive swirling dispersion.

If, for example, these amplitudes bo are chosen that £ tf ι V ₁ * 2 KV and £ ^ ₂ V ₂ * 20 KV (it is assumed that if = 0.8 and V _Q »80 KV), a design such as indicated by the following dates, possible through simple reunings.

X ₁ «Te, X ₂

2 KV; <^? 2 ^V 2 " ^{20 KV}

0 _ΟΛ »80Tc, Z ₁ - 20 λ (where Λ is the

Wavelength of the high-frequency wave in free space iat) L

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U91358 - β -

0 _Ο2 - 47C, / ₂ - Λ.

The high frequency waves currently most frequently used are those which have wavelengths of about 10 om in free space. The resulting distance I ₁ is therefore about 2 meters. An arrangement in which such a long path is provided in front of the accelerating tube of the accelerator, only the total length of the accelerator extended excessively and therefore does not iat wUnsohsnswert. This difficulty can be overcome by keeping the mean velocity of the electrons at a low value, at least until the electrons have passed through the path I ^. For this purpose, if the potential of the point P _{2 is to be} zero and the potential of the cathode of the radiator is to be -V ₀ , the arrangement can be made so that the potential V of the first cavity and the first cavity

Drift tube 9 has the ratio -V ₀ ^ - V ¹ <^ 0.

In an arrangement of the in Flg. 1, the mean speed of the electrons, at least until they _{have traversed the path I 1} , is determined solely by the energy component, which _{corresponds to V Q} - V *. Therefore, if the potentials V _Q and V * are chosen such that, for example, V _Q «is 80 KV and V ¹ - 70 KV, the

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Electron speed 0 ₉ 19 C, so that the length of the path 1-, can be shortened to a value of about 1 / 2.5 of the usual value.

With such an arrangement, however, the excitation of the first cavity 8 by the potential V with high frequency energy becomes a difficult problem in practice. For example, if a voltage Eoohi'requenzenergiequelle sound is to produce -70 KV "the Baufora the device because of the special problems of high voltage insulation is extremely groQ _t so that the device from the viewpoint of space requirements and the economy is unfavorable.

The particular nature of the invention, which is aimed at overcoming the problems indicated, arises from the the following detailed description of a preferred embodiment

In FIG. 2, a lead electron beam 1 is generated in a beam generator which has a cathode 5 in housing 3, a first Anode 4 for drawing off the electron beam, a focusing electrode 6 and a heating device 7. That Housing 5 also includes a first cavity 8 and a first drift tube 9, which is arranged axially in the axis of the electron beam t and at its upstream side E

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U9.1358

τ- 10 -

has an insulator 13 which forms the band wall and with vacuum-tight terminals 14 provided iet._

The first anode 4 is a pulse transmitter 20 for the first anode is connected, while the heating device 7 and the focusing electrode 6 are connected to secondary windings 15 »16 and 17 of a high voltage pulse transformer 19 are connected, which also has a secondary winding t8 be-P, which is connected in the manner shown · Me mentioned secondary windings are sit at their other ends a heating energy source 23 »a VorapannuRgaquelle 24 for the focusing electrode and a bias source 25 for the first anode connected to 21 and 22

* V · are matched apparent resistances »those in the are switched in the manner shown

A further cavity 10 and a second drift tube 11 _ are below the river side of the first mentioned drift tube 9 and arranged coaxially to this “still further subatromic along the path of the electron beam. t is * equal- * aohsig arranged an accelerator tube 2, uia which Focusing apules 39 are arranged coaxially The ends of the accelerator tube 2 are connected to waveguide tubes 40, one of which ends at the lower end of the tube an adapted load 30 for Has radio frequency energy · The other waveguide tube is

9 09 8 11- / 09 3 8

• "BAD ORIGINAL

at its extreme end there is a high frequency modulator 35 (for example bit connected to a magnetron} and ■ with directional coupling elements 31 and an evacuation ■ yeteni 32 provided. The lines 26 and 27 are coaxial

Cable "the one" end of the coaxial cable 26 enters

because the emitter housing 3 is vacuum-sealed

Insulator 12. At each of the directional coupling elements

91 are a transmission element 41 from the waveguide «ur coaxial line »a variable damping member 28, g a phase shifter 29 and an adjusted load fttr H ₀ Oh frequency energy provided.

The high frequency line modulator 33 is connected to its pulse source 34. The mentioned impulse transmitter 20 is old a pulse modulator .35 for the first anode connected and the primary side of the aforementioned high voltage pulse transmitter 19 is connected to a high voltage pulse module gate 36 for the emitter. The pulse source 34 and the pulse modulators 55 and 56 are denoted by i a trigger generator 37 is connected.

In the device described above, a coaxial cable 26 is used for the supply of high frequency waves Sum first cavity 8 is used · In addition, this is coaxial Cable 26 as a winding around the secondary of the high voltage

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impuls transfer device 19 for the beam generator in a similar way Way as the secondary windings 15 «16, 17 and 18 wound« However, it has fewer turns than these windings. Bath The center conductor and the outer conductor of this coaxial cable old the one in the iron core of the pulse transformer 19 Magnetic flux are chained, the pulsating potential assumes the desired state and also plant itself high-frequency waves pass through the interior of a coaxial mode in order to cause an excitation of the cavity 8 su

This means that in the case of the το above described Design and arrangement, as the high-frequency energy source Is coupled to the grounded side of the secondary winding via the coaxial cable, which is the grounding side of the high-voltage pulse transformer, the required high-voltage insulation is not a problem and the space requirement can be miniaturized, whereby an economic advantage is also achieved since the high frequency energy required for the excitation of the cavity 8 is at most about 1 kilowatt as a peak value, possible, for example with the aid of the sighting coupling element 31, only part of the energy of the To take the peak value of a few HW from the high frequency power modulator 33 of the accelerator system and after a suitable adjustment of this part of the energy

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Bit the help of devices, for example by the phase shifter 29 and the variable attenuator 28, to extract this part of the energy from the transmission element 41 from the waveguide to the coaxial line.

The following example is given to illustrate the phase focusing properties of the device shown in FIG and the erate drift tube 9 is pulsating -70TTi daa potential of the cathode 5 is in a similar> 7elae pulsating -80 KVj the effective high frequency voltage a point P (middle of the coupling gap of the eraten cavity 'S) concerns

ir £ jV <yes 2KV; and the effective high-frequency voltage at point P ₁ (center of the coupling gap of the second cavity 10) is ^ 2 ^Y 2 * ² ^ ' Under these conditions, about 90 4 of the total amount of electrons are within 1 0.17Γ | Radian around the mean value of the phase at point P «(the point at which the phase focusing is to take place) agglomerates. Under these conditions, the required length of the first drift tube 9 is about 20 cm.

Depending on the requirements, the excitation of the second

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Cavity 10 also in the same way as the excitation of the first cavity 8 also needs a transformer around which the coaxial cable 26 is wound, not always with the high-voltage pulse transformer for the Be beam generator together. Though for the one in Pig. 2 wound electron accelerator an accelerator shown of a pulse duration of about 6 microseconds and a pulse frequency of about 300 Hz is commonly used can of course be used to carry out the invention an accelerator can be used, which is operated by a pulsating high voltage, which from a wide Range of traditional types and styles selected can.

To further explain the nature and applicability of the Invention is a brief 2usatamenf solution of their - / ir & saiakeit and its novel characteristics.

In general, they become more charged with phase focusing Particles with the aid of an inventive, intermittent working device the potentials of a space, which the charged particles a speed modulation communicates, and a drift space in which the speed-modulated Particles are converted into density-modulated particles, adjusted in a suitable manner and will be the mean metro speed that through this

909811/0938 ORIGINAL BATHROOM

U91358 - 15 -

Räum · «aiid« rnd «n parts reduced« Through this working method «let ·· possible!

1 · dl · T * »hn1 απβψ d« 8 shorten the drift space su and thereby reduce dl · SrUSe and the opening of the device

2. S * the consumption of high frequency energy sur implementation the speed modulation su rerringern and thereby but to contribute to the company's economic liability!

3. Over & lSlge fluctuations in the kinetic energy of the Reduce the phneenfocused particles.

Accordingly, the invention can be applied not only to acceleration erorions for charged particles, as mentioned, but also to high-frequency electron tubes, like s.S. MehrfaohklystronB and Reenatrone and other devices, D. h. see Beieplel "that the essential building" Elements of a multi-purpose glycartridge comprise at least one Input hollow space reeonator on speed modulation ▼ on electrons «a dream about fairies de · geeohwindlgkeitemodulerten Klektronjays and one Exit cavity reonator sur extraction in high frequency form the kinetic knergy of the phase-focused jet · · The Invention is applied in the v / ee to a KIy at rom, daO the potential of the entrance cavity resonator and further

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of the drift space negative ait reference to the potential dt Output cavity resonator is made to operate side, so that in this a phase focusing of the electrons takes place "whereby the advantageous effects 1, 2 and 3 indicated in the table are achieved", the electron beam by exploiting the potential difference «As above the output cavity resonator and the Triftraun kinetic energy is communicated and the beam is brought to enter through the output cavity. In the case of a klystron, this is the aforementioned Effect 2 valuable because of the increase in gain and efficiency.

Ik fall of a Resnatrona is the part »the calibration between the cathode and the control grid are »that part» in which the electrons are phase-focused and the Must have a potential "that deviates from that of the original atlasspalta" as in Chapter 6 of the publication "Theory and Application of Microwaves" by A. B. Bronwell and R. £ · Beam mentions · In this case, a difficulty "which is common to the aforementioned klystron and resnatron" is the problem of how high frequency waves are suggested to the phase focusing obsession. H. the input cavity resonator abBohnitt in the case of a klystron and the area swieohen the cathode and the control grid in

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? all of a Reenatrona. Accordingly, the invention is for such applications particularly well suited to the same effective result as in the aforementioned case of Feeding sound high frequency waves to an accelerator for to achieve charged particles.

From the foregoing it follows that through the invention with a relatively simple design and arrangement a miniaturization of devices for phase focusing of charged particles is made possible, which from the face point of space requirements and economy is very advantageous.

The invention is of course not limited to the preferred embodiment described above, but rather Scanned various changes within its framework

Claim

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Claims (1)

Claim Device for phase foxuaaation of charged particles with a source of charged particles, an impulse transmitter, by the charged particles from the mentioned wave be directed, and means by which the so directed charged particles by excitation of high frequency electromagnetic waves are phaaenXokuaaiert, characterized by a coaxial cable, part of which wrapped around the core of the impulse transmitter, one Source of high frequency Krre & erwellen, and funds for supplying at least a portion of the energy of the high frequency electromagnetic excitation waves from the source to the coaxial cable « 9098 11/0938 BAD ORDINAL