US2520447A - Device for accelerating electrically charged particles, such as electrons and ions - Google Patents

Device for accelerating electrically charged particles, such as electrons and ions Download PDF

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Publication number
US2520447A
US2520447A US33154A US3315448A US2520447A US 2520447 A US2520447 A US 2520447A US 33154 A US33154 A US 33154A US 3315448 A US3315448 A US 3315448A US 2520447 A US2520447 A US 2520447A
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particles
frequency
acceleration
accelerating
time
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US33154A
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English (en)
Inventor
Wideroe Rolf
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BBC Brown Boveri AG Germany
BBC Brown Boveri France SA
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BBC Brown Boveri France SA
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H13/00—Magnetic resonance accelerators; Cyclotrons
    • H05H13/02—Synchrocyclotrons, i.e. frequency modulated cyclotrons

Definitions

  • a circular arrangement of the electrodes has been suggested as especially satisfactory, the particles to be accelerated being forced to move on a circular path by means of a magnetic control field directed perpendicular to the plane of the path.
  • Particles with great inertia exhibit a speed greatly dependent on the energy of the particle, the result of this being that either the acceleration frequency or the path radius of the particles or both, with changing particle energy, must be changed so that the acceleration frequency shall always agree with the frequency of passage of the particles, or a whole multiple of the same, which is necessary if the particles are to be accelerated a number of times in the acceleration stretches between each two successive electrodes.
  • the purpose of the present invention is to lessen or to prevent as far as possible the loss in particles by facilitating the collection of the particles during the change from one synchronous state into the next one.
  • the time curve of the frequency (in) of the acceleration energy during each synchronism change is so fitted to the time curve of the passage frequency (hr) of the accelerated particles that at the moment of the agreeing of th frequency (In) of the accelerationenergy with a multiple (M) (selected at the time) of the passage frequency UT) of the particles, the derivative, with time, of the frequency of the acceleration energy corresponds to the derivative of the passage frequency of the particles, with time,
  • Fig. 1 shows a practical example for the case where the particles are accelerated with the aid of a single acceleration system.
  • the acceleration frequency (In) which has a serrated course (solid-line curve in Fig. 1) should run proportional to the frequency (11') of the particles moving along subsynchronously, in its periodically ascending sections, 1.
  • B represents the control field for radius R at moment t R represents the mean radius of the paths of the particles 0 represents the speed of light 1 e represents kinetic energy at rest of the particles m represents the inertia of the particles e represents the charge of the particles
  • the frequency of the circling particles (IT) is shown by the dot and dash curve sections, where, however, it is always the passage frequencies multiplied by a definite factor (M) that are entered. In the interval, for instance, be-
  • the acceleration frequency is diminished from the value C to D.
  • the solid-line curve I shows the serrated frequency 'course (modulation) of one accelerating system
  • the solid-line curve II the frequency course (modulation) of the other accelerating system, a phase difference of approximately 180 existing between the two modulations.
  • the system II starts, its derivative of the frequency with time corresponding at point D, ac-
  • the acceleration frequency is to be influenced cording to the invention, to the derivative of the frequency with time of point C of system I.
  • This overlapping of the effect in point of time of the two accelerating systems can be achieved by selecting the time duration of the frequency rise for the two systems to be at least a fifth longer than the duration of the frequency drop.
  • the acceleration frequencies are so to be selected in relation to each other that in the interval F-G, the passage frequency of the particles runs subsynchronously to the two acceleration frequencies as exactly as possible.
  • the voltage course in the field (F-G) of synchronism change is preferably chosen so that in the period (F-G) in which the tangents on the curves of the two acceleration frequencies (I and H) are approximately parallel, the voltage at the one high frequency generator drops to zero and that or the other high frequency generator rises from zero to its maximum value.
  • the change in acceleration frequency in the sense of Figs. 1 and 2 can be carried on without difficulty with means generally known, such for instance as rotating condensers, mechanically variable inductances and also by a variable premagnetization of magnetic materials, the magnetization curve of which does not ascend linearly.
  • the places 38 and Bil of the hollow cylinders l0 and 42 are connected to the ends of thecowpling coil 52 grounded at the middle.
  • a high frequency generator I this transmitter being indicated only diagrammatically by a, rectangle.
  • the places 4'8 and Slot the hollow cylinders ii and II are to be connected to the ends of the coupling coil 53 that is likewise grounded at the middle.
  • a high frequency generator II that is again indicated only by a rectangle.
  • the modulation of the transmitter II isto be displaced in relation to the transmitter I according to Fig, 2 by approximately which can be done easily by relative adjustment of segments 58 and 51.
  • the contact mechanism associated with generator I is seen to be comprised of a circular array of stationary contacts 64 corresponding in number to, and in alignment with; the stationary condenser plates 58 and a rotating wiper contact 65 secured upon the shaft of motor 60, the rotating contact being angularly aligned with the rotating condenser plate 56. All of the stationary contacts '64 are interconnected as shown to a common conductor lead 68, the rotating contact is connected by way of the usual slip ring produced by generator I during the desired frequency decreasing interval in each cycle of frequency modulation.
  • a similar rotating contactor arrangement is provided for generator II, the array of stationmy contacts being denoted by numeral 68, the rotating contact by numeral 69, and'the conductor leads by and II.
  • the plates 56 and 58 are connected in parallel electrically to the coupling coil 52, and the plates 51 and 59 in parallel to coupling coil 53, and a synchronous motor 60 drives the two movable segments 56 and 51.
  • the motor 60 is driven by the same alternating current network 63 that likewise excites the magnets for producing the magnetic control field that keeps the accelerated particles on the predetermined circular path. Only one exciting coil 6
  • acceleration of the particles can be carried on with a single generator as indicated in Fig. 1.
  • all the acceleration electrodes in Fig. 3 are connected for instance only to one transmitter I, and the segments of the plates 56 and 58 are to be shaped so that the frequency course shown in Fig. l is obtained.
  • Transmitter II, and the segment plates 51 and 59 are then eliminated.
  • Device for the multiple acceleration of electrically charged particles by means of high frequency electric fields of potential comprising an enclosed evacuated chamber providing an orbital path along which said particles are accelerated, a system of electrodes arranged in said chamber along said ath, means for applying a frequency modulated potential to said electrodes to produce corresponding potential fields through which said particles pass, said potential vary cyclically with time between minimum and maximum limits in stepped diminishing multiples of the constantly increasing frequency at which the particles pass through said potential fields, and means establishing a time varied magnetic guiding field through said path normal to the plane thereof distinguished by the feature that the time course of the frequency of said potential fields during each change in synchronism is suited to the time course of the passage frequency of the particles such that at the instant the frequency of said potential fields reaches a match with a given one of the said multiples of the passage frequency of the particles the derivative of the frequency with time of said potential fields corresponds to the derivative of the passage frequency of the particles with time multiplied by said given multiple.
  • Device for the multiple acceleration of electrically charged particles by means of high frequency electric fields of potential comprising, an enclosed evacuated chamber providing an orbital path along which said particles are accelerated, a system of electrodes arranged in said chamber along said path, means for applying a frequency modulated potential wave to said electrodes to produce corresponding potential fields through which said particles pass, said potential wave having a sawtooth characteristic varying cyclically with time between minimum and maximum limits in stepped diminishing multiples of the constantly increasing frequency at which said particles pass through said potential fields, the
  • Device for accelerating charged particles as defined in claim 2 wherein the quotient of the largest and smallest .values of the frequencies of 7 ing asynchronously during such period and diminishing their radius of path constantly, and, after the particle collection is completed, it coincides, during an additional fifth of the total rise in frequency, with the value proportional to the frequency of the particles rotating in a subharmonic manner.
  • Device for accelerating charged particles as defined in claim 2 characterized by the fact that on a, basis of time the period during which the frequency of said potential field falls from maximum to minimum does not exceed one fifth of the period during which said frequency rises from minimum to maximum value.
  • Device for accelerating charged particles as defined in claim 2 characterized by the fact that during the period in which the frequency of said potential field falls from maximum to minimum values, the strength of such field is reduced to a value not exceeding one half its maximum value.
  • Device for accelerating charged particles as defined in claim 1 characterized by the fact that the least two systems of the high frequency potential fields are utilized in alternation for accelerating the particles, each said system being energized through a separate source of high frequency oscillations.
  • Device for accelerating charged particles as defined in claim 1 characterized by the fact that at least two systems of high frequency potential fields are utilized in alternation for accelerating the particles, and each said system is supplied by its own high frequency generator, the frequency of one system decreasing during a part of the time where the frequency of the other system increases, said system being arranged such that during the common time period in each cycle of frequency variation in which the frequencies of both systems exhibit a rising characteristic, the particles run substantially in a. sub-harmonic manner to the frequencies of both said systems.
  • Device for accelerating charged particles as defined in claim 1 characterized by the fact that at least two systems of cyclically varied high frequency potential fields are utilized in alternation for accelerating the particles, and each said system is supplied by its own high frequency generator, the voltage of each system during the portion of the cycle in which the frequency de creases being reduced to a value not exceeding one half of the value which obtains during that portion of the cycle in which the frequency increases, said voltages reatta'ining said latter value before the change in synchronism has been completed.
  • Device for accelerating charged particles as defined in claim 1 characterized by the fact that at least two systems of cyclically varied high frequency potential fields are utilized in alternation for accelerating the particles, and each said system is supplied by its own high frequency generator, said systems being arranged such that during the common time period in each cycle of frequency variation in which the tangents to the two frequency curves are substantially parallel the'voltage of one system falls off to zero and the voltage of the other system rises to its maximum value.
  • Device for accelerating charged particles as defined in claim 1 characterized by the fact that at least two systems of cyclically varied high frequency potential fields are utilized in alternwtion for accelerating the particles, and each said system is supplied by its own high frequency generator, said systems being arranged such that during the common time period in each cycle of frequency variation in which the tangents to the two frequency curves are substantially parallel the voltage of one system falls off to zero and the voltage of the other system rises to its maximum value, said common time period being greater than one third of one oscillation cycle of the phase oscillations of the particles and less than threefold.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Particle Accelerators (AREA)
US33154A 1947-06-16 1948-06-15 Device for accelerating electrically charged particles, such as electrons and ions Expired - Lifetime US2520447A (en)

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Application Number Priority Date Filing Date Title
CH672670X 1947-06-16

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US2520447A true US2520447A (en) 1950-08-29

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US (1) US2520447A (xx)
BE (1) BE483157A (xx)
CH (1) CH260980A (xx)
DE (1) DE844950C (xx)
FR (1) FR967585A (xx)
GB (1) GB672670A (xx)
NL (1) NL78644C (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2683216A (en) * 1946-01-31 1954-07-06 Bbc Brown Boveri & Cie Apparatus for accelerating charged particles by causing them to pass through periodically reversing potential fields
US3688203A (en) * 1970-11-10 1972-08-29 Kev Electronics Corp Scanning system for ion implantation accelerators

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE941561C (de) * 1953-08-28 1956-04-12 Siemens Ag Synchrozyklotron
US4667111C1 (en) * 1985-05-17 2001-04-10 Eaton Corp Cleveland Accelerator for ion implantation

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2242888A (en) * 1938-02-16 1941-05-20 Telefunken Gmbh Ultra short wave oscillation generator
US2398162A (en) * 1941-12-16 1946-04-09 Research Corp Means and method for electron acceleration

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2242888A (en) * 1938-02-16 1941-05-20 Telefunken Gmbh Ultra short wave oscillation generator
US2398162A (en) * 1941-12-16 1946-04-09 Research Corp Means and method for electron acceleration

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2683216A (en) * 1946-01-31 1954-07-06 Bbc Brown Boveri & Cie Apparatus for accelerating charged particles by causing them to pass through periodically reversing potential fields
US3688203A (en) * 1970-11-10 1972-08-29 Kev Electronics Corp Scanning system for ion implantation accelerators

Also Published As

Publication number Publication date
NL78644C (xx)
GB672670A (en) 1952-05-28
FR967585A (fr) 1950-11-07
CH260980A (de) 1949-04-15
BE483157A (xx)
DE844950C (de) 1952-07-28

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