US2553305A

US2553305A - Injection compensation in highenergy particle acceleration

Info

Publication number: US2553305A
Application number: US92768A
Authority: US
Inventors: Theodore M Dickinson
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1949-05-12
Filing date: 1949-05-12
Publication date: 1951-05-15
Anticipated expiration: 1968-05-15

Description

May 15, 1951 I T. M. DICKINSON INJECTION COMPENSATION IN HIGH-ENERGY PARTICLE ACCELERATION 2 Sheets-Sheet 1 Filed May 12, 1949 f ig l.

Inventor: eodre Mbickinson, by f I 5 His Attorney.

May 15, 1951 'r. M. DICKINSON 2,553,305

' INJECTION COMPENSATION IN HIGH-ENERGY PARTICLE ACCELERATION Filed May 12, 1949 2 Sheets-Sheet 2 FLLX INKING SATURA BLE STRIP FLUX DENSITY VOLTAGE INBLTGEE 7R WIND-INT; 60115526 WITH SATURABLE STRIP Inventor": Theodore M.Dickihson,

by W 5,

His Attor ney.

Patented May 15, 1951 INJECTION CUMPENSATION IN HIGH- ENERGY PARTICLE ACCELERATION Theodore M. Dickinson, Schenectady, N. Y., assigncr to General Electric Company, a corporation of New York Application May 12, 1949, Serial No. 92,768

17 Claims. 1

The present invention relates to apparatus for the acceleration of charged particles by magnetic induction effects. The invention finds useful application in connection with apparatus of the general character described in. United States the name of Willem F. Westendorp on September 15, 194.5, copending application Serial No. 639,462, filed in the name of Herbert C. Pollock and Willem F. Westendorp on January 5, 1946 (now matured into Patent No. 2,485,409), and copending application 724,066, filed in the name of John P. Blewett on January 24, 1947 (now matured into Patent No. 2,465,786), all of said copending applications being assigned to the General Electric Company.

Apparatus of the character referred to typically utilize at least in part a cyclically varying magnetic flux for accelerating charged particles in an orbital path. After the particles have been accelerated to desired energy levels, they may be accelerated still further by other means or they may be diverted from the orbit and utilized for the production of useful biological or other effects.

In the operation of magnetic induction apparatus of this type, a primary problem is experienced in the suitable introduction of charged particles into the stable orbit region. If proper particle capture is to be realized, suitable correlation between the injecting means and the cyclically varying flux must be attained.

A principal object of the present invention is" to provide improved means for correlating particle injection with the cyclically varying flux.

The cyclically varying flux upon which acceleration of the particles depends, is conveniently provided by the action of a cyclically varying electrical current; and, when it is so produced, acceleration in the desired direction occurs only during alternate half cycles, even though useful op eration may be extended by means described in the above-mentioned copending application, Serial No. 616,634. The most advantageous time for particle injection occurs near the time when the flux is beginning to build up in a direction favoring the desired acceleration. To insure maximum particle capture, the kinetic energy of the particles at the instant of injection should match the values of the flux such that continuous acceleration will occur along a stable orbit of desired radius.

It has been proposed heretofore to correlate the particle injection with the flux by the provision of a magnetic path which is adapted to change abruptly and reversibly from a saturated to an unsaturated condition in accordance with the variations of the flux. By linking an appropriate circuit with the magnetic path, sharp pulses of voltage bearing a timed relation with respect to the variations of the flux are obtained and utilized to initiate particle injection. :Such an expedient assures injection at the proper time, if after the desired time has been selected, the magnitude of the varying flux does not change. If such changes do occur, the kinetic energy of the particles at injection will not be Of proper value and ineflicient capture will result. The present invention insures proper injection energies at all times during the operation of the apparatus by the provision of suitable circuit means to cause the injection energy to be proportional to such changes.

The features of the invention desired to be protected herein are pointed out with particularity in the appended claims. The invention itself together with further objects and. advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawings in which Fig. 1 is a simplified front elevation of a particle accelerator with which the invention may find useful application; Fig. 2 is a sectionalized view of the particle source portion of the accelerator tube; Fig. 3 is a circuit diagram illustrating the electrical interrelation of the various components embodied in the invention; Figs. 4 and 5 inclusive are graphical representations useful in explaining the invention, and Figs. 6 and 7 are circuit diagrams illustrating alternative electrical interrelations of various components embodied in the invention.

Referring particularly to Figs. 1 and 2, there is shown a, magnetic induction accelerator comprising a rectangular magnetic core I having

pole piece members

2 and 3 located within the opening 6.

Pole piece members

2 and 3 are suitably tapered at their opposed faces as indicated at 5 and 6 to provide a desired magnetic field configuration. To provide energization for the magnetic structure comprising the core and pole pieces, serially-connected magnetizing windings l and 3, which may be connected to a suitable source of voltage (not shown), are respectively concentrically arranged about

pole piece members

2 and 3. Between the opposed pole piece members, there is located a closed rotationally symmetrical glass vessel 9 which defines within its interior an annular chamber 1 l. The vessel may be highly evacuated. and coated on its interior surface with a conductive layer of silver or other suitable material ii! for the purpose of reducing wall-charging. For the purpose of introducing charged particles into the vessel there is provided within the region of influence of the magnetic field generated by the magnetizing windings a charged particle source comprising an electrode l3 having an opening for the egress of electrons, a focusing member Hi and a thermionic cathode which may be energized by a suitablesource of potential (not shown) through leads I6 and I7. Electrode 53 may be connected to layer 52 by a lead 13 and to ground through a lead it for a purpose to be more fully described hereinafter in connection with Fig. 3. Connected to shield M and to lead it is a lead it which together with leads H and is may be insulatingly introduced through the vessel 9 by means of a suitable glass seal. Between the opposed faces of the pole piece members, laminated disks 2' are supported by insulating spacers 3 to provide the proper reluctance within the flux path enclosed by the vessel.

As will be readily understood by those skilled in the art, the magnetizing coils i and 8, when energized by a suitable cyclically varying current, establish a similarly cyclically varying magnetic flux within the magnetic structure. When charged particles are introduced into the region of influence of this varying flux by the particle source within the vessel It, they will be accelerated along an orbital path providing a certain relationship obtains. In general, it may be stated that successful acceleration may be achieved if =21rT 2H1- where '4) is the flux included within or linking the stable particle orbit, r is the radius of the aforesaid particle orbit and Hr is the field strength at the orbit. This relation means that the flux s rnust'be twice as great as that which would be produced by a homogeneous field equal to the fi'eld I-Ir extending over the entire area enclosed by the orbital path. This condition may be realized'by properly arranging the reluctance of the magnetic circuit with such members as laminated disks 2' and

pole piece members

2 and 3.

IF-he charged particles, i. e. electrons, provided by filamentary cathode 15 are affected in two ways when they are injected into the stable orbit region. First, the field established at the orbit tends to cause the electrons to follow an inwardly spiralling path. Secondly, the flux enclosed by the orbit or any particularelectron produces an electric field tending to accelerate the electrons. Thus, the electrons may be considered to be accelerated by a portion of the cyclically varying flux which links the orbital path while being guided along the path by the cyclically varying magnetic field established along the orbit.

As has been heretofore explained, acceleration of the electrons takes place only during alternate half-cycles of the varying flux, and therefore the electrons must be injected during each half cycle in which acceleration is desired. This may be accomplished by driving the electrons emitted by cathode l5 from the particle source at a timed instant with respect to the varying flux. As will be observed, if cathode i5 is abruptly caused to assume a negative potential with respect to electrode it, the electrons within the source will be subjected to a repelling force which will drive them through the opening provided for their 4 egress into the region of influence of the varying flux.

The energy at which the electrons must be injected will be determined by the value of the cyclically varying flux at that instant. In order to assure most efllcient electron capture, the energy of the electrons must match the intensity of the guide field at inj ection'to make their radius of curvature approximately equal to that of the stable orbit of the accelerator apparatus. For energies at which injection is customarily accomplished, the energy required for such matching will vary approximately as the square of the field strength for a given radius of curvature. The present invention insures the required matching by providing means for injecting the electrons at an energy level proportional to the magnitude of the cyclically varying flux and at a time corrected to compensate for the square law requirement.

Reference may now be had to Fig. 3 wherein portions representative of elements of an induction accelerator such as that shown in Figs. 1 and 2 are similarly identified. For driving cathode l5 abruptly to a negative potential with respect to electrode I3, there is shown a pulsegenerating circuit comprising an energy-storing device represented by a capacitor 20 in circuit with a grid-controlled gaseous discharge device 2! and a pulse transformer 22. For the purpose of charging capacitor 25!, a Winding 23 may be placed so as to be inductively linked by the cyclically varying flux of the accelerator; e. 'g., Wound about the magnetic core I as shown. In circuit with winding 23 are an adjustable autotransformer 2 a step-up transformer 25 and diode rectifier tube 26, the cathode of which is connected to capacitor 20 and the plate 27 of discharge tube 2|. As maybe readily understood capacitor 20, after it has been charged by the voltage induced in winding 23 as a result of the cyclical variations of flux, may be discharged through the discharge device 2! and the primary of pulse transformer 22 by the application of a suitable triggering voltage or signal to grid 28. This discharge causes a voltage pulse to be induced in the secondary of pulse transformer 22, such pulse appearing between the filamentary cathode i5 and ground since one end of the secondary of transformer 22 is connectedto the cathode i5 and the other to ground. Electrode I3 is also connected to ground through lead I9 and therefore this voltage pulse, which may be in the order of kilovolts, results in the oathode 15 being driven to a negative voltage with respect to electrode !3. As a consequence, electrons provided by heating the cathode with a suitable source'of potential, conventionally shown as battery 29, are projected into the region of influence of the cyclically varyingfiux so that they may be accelerated to the desired energy levels.

For the purpose of timing the application of the hereinbefore mentioned voltage to grid 2-8 with respect to the cyclically varying flux, there is provided a magnetically saturable core or strip 30 around which is placed a winding 3|. As the flux which links the saturable core varies, an abruptpulse is produced in winding 3i and is transmitted through blocking capacitor 32 to grid 28. To suitably bias discharge device 2| biasing battery 33 is connected in series withgrid resistor 31 between the grid 28 and cathode 35.

To obtain a better understanding of the timing of the application of the abrupt pulse to grid 28, reference may be had to Figs. 4 and 5. In Fig. 4 the curve labeled may be considered as representative of the cyclically varying flux generated by windings l and 8 and the points may be considered as the time at which particle injection is desired in order that advantageous acceleration may be procured. In Fig. 5 the curve label ,8 may be considered as representative of the variations in magnetic flux linking the saturable strip or core 38. It will be observed, due to the ready saturability of the core, that the only changes of magnetic flux in the core occur near regions of reversal of the curve The curve 221 appearing in Fig. 5 indicates the abrupt voltage pulses which will be induced in windings 3| as a result of the changes in magnetic flux within the saturable core 33.

It will be noted that the maxima of the curve or occur approximately at the points of zero flux indicated by the curve 5. The relative relation of the maxima of curve or with respect to the curve ma be altered by the suitable application of a biasing flux to the saturable core at. This biasing flux may be produced by means of a current flowing through the winding 3| (Fig. 3) supplied from a battery 42 and adjusted in value by variable resistor 33. Choke coil 39 having a low impedanc to the biasing current but a high impedance to the abrupt pulse or voltage produced in the winding 3! by the varying flux prevents this abrupt pulse from being by-passcd to ground throu h the relatively low impedance of resistor 38 and battery 22 and thus from failing to reach the grid 28 of discharge device 2! through capacitor 32. The biasing current through winding 3| produces a biasing field in saturable core 36 which opposes the field produced across the pole faces 2 and 3 during the accelerating half cycle and thus causes the flux in the saturable strip to pass through zero at a time later than does the guide field. Accordin ly, the application of the voltage pulse to grid 28 of discharge device 2! may be arranged such that the particle source will be energized at a particular value of the cyclically varying flux whereby the particles may be injected into the region of influence of the varying flux at a time corresponding to the correct value for continuous acceleration.

It will be readily understood, however, that after the timing of the voltage pulse, represented b curve 221, has been set by adjustment or" the biasing flux in the saturable core 30 for a particular energy level of the source, if the magnitude of the cyclically varying flux changes, the

energy level of the injected particles will no z:

longer match the value of the cyclically varying flux at the instant of injection and ineflicient capture will result. To correct for this, either the energy level of the injected p rticles or the time of injection or both must be changed.

As has been hereinbefore stated, the energy level at which the particles should be injected for proper capture is proportional to the square of the intensity of the guide field at the instant of injection and in turn, therefore, is proportional to the square of the magnitude of the cyclically varying flux wave. If the energy level of the injected particles is caused to change as the square of this magnitude, the time of injecto change the time of injection to maintain proper capture. In practice, over the small range of 6 fluctuations of the cyclically varying current used to excite the magnet, the time for successful injection of particles of a given energy level varies nearly as a linear function of the magni tude of the guide field. Thus, it will be readily understood, for an energy level of the particles Which varies in a linear manner with the magnitude of the guide field, if the time of injection is caused to vary in a linear manner with the magnitude or" the guide field, a proper match of energy level and guide field can be maintained.

With reference again to Fig. 3 and to the previous description in connection therewith, it will be observed that the value of charge on capacitor 28 is directly proportional to the magnitude of the varying flux since the charging voltage for capacitor 2c is supplied by winding 23. lhis meansthat the injection energy level will vary linearly with the magnitude of the cyclically varying flux and secure one desired proportionalit because the magnitude of the pulses supplied by capacitor 2b to the source will be directly proportional to the magnitude of the varying flux.

In order to secure a second direct proportionality between the injection of particles and the varying flux, there is provided a means for altering the timed relation of the voltage pulse applied to grid 28. As shown, this means comprises a biasing supply for saturable core 30 which is indicated generally by the numeral 36 and includes a variable resistor 31, a choke coil 40 connected to thegrid circuit of tube 2| at 43, and an energizing step-down transformer 4|, the primary of which is connected across winding 23. Biasing supply 36 provides an additional biasing current through winding 3| which, combined with the biasing current from the hereinbefore described current from battery 42, produces a biasing flux in saturable core 39 and determines the time at which particle injection occurs. By proper adjustment of variable resistors 3'! and 38, a condition may be obtained whereby injection of particles occurs at the correct time for matching a particular guide. field strength. When random fluctuations occur in the magnitude of the current through exciting coils '1 and 8; resulting in random fluctuations of the magnitude of the cyclically varying flux, corresponding variations appear in the induced voltage in winding 23 and cause similar variations in that portion of the biasin current through coil 31 derived from biasing supply 36. This automatically alters the timed relation of the voltage pulse applied to grid 23 in direct proportion to magnitude of the cyclically varying flux.

It will now be evident that the requirements for successful injection are provided even though random variations in the cyclically varying flux may occur. If the magnitude of the varying flux changes, then both the injection energy level and the time of injection will vary in direct proportion thereto and the particles will be injected at the desired combination of energy level and time.

.An alternative arrangement for timing the application of the voltage pulse to the grid of discharge device 28 is shown in Fig. 6 wherein portions corresponding to portions of Fig. 3 are similarly identified. Voltage induced in winding 23 by the cyclically varying flux is applied through potentiometer 44 and transformer 45, the secondary of which is connected inseries with a choke 46, a fixed resistor 41, and the secondary of a transformer 48. The primary of transformer 48 is connected through potentiometer' 49; to. a:.cyclically; varying sourcezoi. cur-- rent-having a: constantipeak magnitudeand :the.

same frequencyas. that ofthe cyclically: varying;

flux: By adjustmentzof potentiometers 44 and. the: proper voltages are. obtained inthesecondary windings of. transformers. 45 their. additiveefiect. is similar to thatdescribed in: connection: with. Fig. 3... The resistor 41 is made'l'argewith respect to. the impedance of. the: remainder of the circuit in order thatthe. cyclie cally: varying." biasing current willbe. substantially inphase with the induced voltage'of. windin 23, thereby'causing-the maximum valueof bias to occur near. zero guidefield. when the; biasing. efiect is required.

Although only: one winding-23 has. been shown.

will occur at theatime: ofiinjection, thereby: requir-- inga. smaller. root .mean. square value-pi; current; As afurther expedient. an amplifier or pulse shaper: may be interposed between winding 31 andgrid 28 to steepen the. wave front ofrithezpulse as it' i's applied to grid 2 8' wherebythe; regularity of" the firing of discharge deviceli: may be. im: proved. Also, it will. be observedzthat'. capacitor 20may bereplacedby a. lumped; constant line which will perform a. similar function. in storing energ-yior discharge'bydischarge: device: 2.l It will likewise be understood that therhereinb-efore mentioned flun'whichlinks theorbital: path to produce acceleration may-.be'generated separately from the magnetic field: establishedalong the orbit. In such event, the advantageousap-plica tion of this invention may: be secured in: accord, ance with the principles herein advanced since the magnetic induction acceleration relationship between the-accelerating flux and theguide field must be maintained 'and injection conditionsmay be-relatedthereto= in a similar manner.

While the invention has been described by reference" toparticular embodiments, it will be understood that numerous modifications may: be made-by those skilled in the art withoutactually departing from the invention. I therefore aim int-he appended claims to cover" all such equivalent variations as come within the true spirit and scope. of: the foregoing .disclosurel VifhatIclaiin as new; anddesire. to: secure. by Letters-Patent of the United States. is;

l. Iii-apparatus for the-acceleration of charged particlesinan orbital: path. by the production of a cyclicallyvarying flunrwhichzlinks: the path to accelerate the particles and establishes a magnetic held to constrain the; particlesto: thapath, the combination which comprises a source of charged particles adjacent the path and efiective when energized to iniect charged panticles into the path, means for energizing said sourcewith energy pulsesproportional' to the magnitude of the-varying flux in response -to.a triggering voltage, a winding having a magneticall-y saturable corelinked bythevarying flux t'o generateias periodio voltage for triggering said means in timed and 48 such that.

relation to the-.varyingfiux, and awinding linked;

by the; varying flux to. generate acurrentproportional to'the magnitude of the flux. and connected.

to said first named winding to produce a mag,- netic bias. in. said core for altering the time at which the. periodic triggering voltage is generated.

neticfield to constrain the particles, to the path,

the combination which comprises a source of.

charged particles adjacent the path andeffective when energized to inject charged particles. into thepath, means 'for energizing said source with. energy pulses of varying magnitude in response.

to a triggering voltage including a.fir st winding linked by the varying, fiuxto supply energy. for.

- the pulses in proportion to the. magnitude, of the.

flux, a secondwinding havingamagnetically sat.- urable core linked by the varying flux to, generate aperiodic voltage for triggering said means. in timed relation to thevarying. flux, andabias supply circuitenergized by said first winding and connected to said second. winding to produce. a. magnetic bias in said core. for altering the, time, at. which, the periodic. triggering voltage isgenerated.

3. In apparatus for the accelerationoi charged particles in an orbital path by the production of acyclically varying flux which links the path, to accelerate the particles and establishes a magnetic field to constrain the particles to the path, the combination which comprises a source of charged particles. adjacent the path and effective when energized to. inject charged particles into. the path, means. for energizing said source with energy pulses of varyingmagnitude in response to a triggering voltage including a first winding linked by the varying flux. to supply energy for the pulses in proportion to the magnitude of the flux; a. second winding having a magnetically saturable core linked by. the varying flux to. gen.- erate. a periodic voltage for triggering saidv means in timed relation. to the varying flux; and abias supply circuit energized by a third winding linked by the varying flux to produce acurrent in said circuitproportional to the magnitude of thevarying flux. and connected to said second winding to produce a magnetic bias in said core for al.- tering: the time at which the periodic triggering voltage is generated.

4. In apparatus for'the acceleration of charged particles in an orbital path by the production of a cyclically varying flux which links the path. to accelerate the particles and establishes a magnetic field to constrain the particles to the path, the combination which comprises a source of charged particles adjacent the path and effective when energized to inject charged particles into the path, means, for energizing said source with energy pulses of varying magnitude in response to a triggering signal including a first winding linked by thev varying flux to supply energy for the pulses; in proportion to the magnitude oi:th.e flux, a second winding having a magnetically saturable. core linked by the varying flux to generate a periodic voltage for triggering said means in timedi relation to the varying flux, and a bias supply circuit energized by said first winding and serially connected to said second'winding to supply a biasing current for altering the time at vighich the periodic triggering voltage is. genera ed.

5. In apparatus for the acceleration of charged particles in an orbital path by the production of a cyclically varying flux which links the path to accelerate the particles and establishes a magnetic field to constrain the particles to the path, the combination which comprises a source of charged particles adjacent the path and effective when energized to inject charged particles into the path, means for energizing said source with energy pulses of varying magnitude in response' to a triggering signal including a first winding linked by the varying flux to supply energy for the pulses in proportion to the magnitude of the flux, a second winding having a magnetically saturable core linked by the varying flux to generate a periodic voltage for triggering said means in timed relation to the varying flux, and a bias supply circuit energized by a third winding linked by the varying fiux to produce a current in said circuit proportional to the magnitude of the varying flux and serially connected to said second winding to supply a biasing current for altering the time at which the periodic voltage is generated.

6., In apparatus for the acceleration of charged particles in an orbital path by the production of a cyclically varying flux which links the path to accelerate the particles and establishes, a magnetic field to constrain the particles to the path; the combination which comprises a source of charged particles adjacent the path and effective when energized to inject charged particles into the path; means for energizin said source including an energy-storing device, a winding linked by the flux and in circuit with a rectifier for charging said energy-storing device to a voltage proportional to the magnitude of the flux, and a grid-controlled gaseous discharge device in circuit with said energy-storing device for discharg in said energy-storing device wh n rendered conductive by a triggering signal to produce energy pulses for said source; means for rendering said discharge device conductive including a winding having a magnetically saturable core linked by the flux to produce a periodic voltage in said last named Winding for triggering said discharge device in timed relation to the cyclical variations of the flux; and means for alterin the timed relation of rendering said discharge device conductive including a bias supply circuit energized by said first named winding and connected in circuit with said second named winding to produce a magnetic bias in said core.

'7. In apparatus for the acceleration of charged particles in an orbital path by the production of a cyclically varying fiux which links the path to accelerate th particles and establishes a magnetic field to constrain the particles to the path; the combination which comprises a source of charged particles adjacent the path and effective when energized to inject charged particles into the path; means for energizing said source including an energy-storing device, a winding linked by the flux and in circuit with a rectifier for charging said energy-storing device to a voltage proportional to the magnitude of the flux, and a grid-controlled gaseous discharge device in circuit with said energy-storing device for discharging said energy-storing device when rendered conductive by a triggering signal to produce energy pulses for said source; means for rendering said discharge device conductive including a winding having a magnetically saturable core linked by the flux to produce a periodic voltage in said last named winding for triggering said discharge device in timed relation to the cyclical variations of the flux; and means for altering the timed relation of rendering said discharge device conductive including a winding linked by the flux to generate a current proportional to the magnitude of the flux and connected in circuit with said second named winding to produce a magnetic bias in said core.

8. In apparatus for the acceleration of charged particles in an orbital path by the production of a cyclically varying flux which links the path to accelerate the particles and establishes a magnetic field to constrain the particles to the path, the combination 'which'comprises a source of charged particles adjacent the path and effective when energized to inject charged particles into t1 e path, means for energizing said source with energy pulses proportional to the magnitude of the Varying flux in response to a triggering voltage, a winding having a magnetically saturablc core linked by the varying flux to generate a periodic voltage for triggering said means in timed relation to the varying fiux, and currentsupplying means connected to said winding for magnetically biasing said core to alter the time at which the periodic triggering voltage is generated including a source of direct current and a winding linked by the varying flux.

9. In apparatus for the acceleration of charged particles in an orbital path by the production of a cyclically varying flux which links the path to accelerate the particles and establishes a magnetic field to constrain the particles to the path. the combination which comprises a source of charged particles adjacent the path and effective when energized to inject charged particles into the path, means for energizing said source with energy pulses of varying magnitude in response to a triggering voltage including a first winding linked by the varying flux to supply energy for the pulses in proportion to the magnitude of the flux, a second winding having a magnetically saturable core linked by the varying flux to generate a periodic voltage for triggering means in timed relation to the varying flux, and currentsupplying means connected to said second winding for magnetically biasing said core to alter the time at which the periodic triggering voltage is generated including a source of direct current and a current-conducting circuit energized by said first winding.

10. In apparatus for the acceleration of charged articles in an orbital path by the production of a cyclically varying flux which links the path to accelerate the particles and establishes a magnetic field to constrain the particles to the path, the combination which comprises a source of charged particles adjacent the path and effective when energized to inject charged particles into the path, means for energizing said source with energy pulses of varying magnitude in re sponse to a triggering voltage including a first winding linked by the varying flux to supply energy for the pulses in proportion to the magnitude of the flux, a second winding having a magnetically saturable core linked by the varying iux to generate a periodic voltage for triggering said means in timed relation to the varying flux, and current-supplying means connected to said second winding for magnetically biasing said core to alter the time at which the periodic triggering voltage is generated including a source of direct current and a winding linked by the varying flux.

11. In apparatus for the acceleration of charged particles in an, orbital path by the production of a cyclically varying flux which links the, path to accelerate the particlesv and establishes a magneticfield to constrain the particles to the path; thecombination which comprises a source' of charged particles adjacent the path and effective when energized to inject charged particles into the path; means for energizing said source including; an energy-storing device, a winding linked by the varying flux and in circuit-with a rectifier for charging said energy-storing device to-a voltage proportional to the magnitude of the varying flux, and a grid-controlled gaseous discharge device in circuit with said energy-storing device fordischarging said energy-storing device whenrendered conductive by a triggering signal to produce energy pulses for said source; means for; rendering said discharge device conductive including a winding having a magnetically saturablecore linked by the varying flux to produce a periodic voltage in said last named Winding for triggering said discharge device in timed relation to the cyclical variations of the flux; and current-supplying means connected to said second named winding ior'magnetically biasing said core to alter the time at which said discharge device is rendered conductive including a source of direct current and a current-conducting circuit energized by said first named winding.

12. In apparatus for the acceleration of charged particles in an orbital path by the productionof a cyclically varying flux which links the path to accelerate the particles and establishes a mag,- neticfield to constrain the particles to the path; the combination which comprises a source of charged particles adjacent the path and effective when energized to inject charged particles into the path; means for energizing said source in.- cluding an energy-storing device, a winding linked by thevarying flux and in circuit with a rectifier for charging said energy-storing device to a voltageproportional to the magnitude of the varying flux, and a grid-controlled gaseous discharge device in. circuit with said energy-storing device for discharging said. energy-storing device when rendered conductive by a triggering signal to produce energy pulses for said source; means for rendering said discharge device conductive including a winding having a magnetically saturable core linked by the varying flux to produce a periodic voltage in said last named winding for triggering said discharge device in timed relation to the cyclical variationsof the flux andcurrentsupplying means connected to said second named winding for magnetically biasing saidlcore toalter s the-timed relation of rendering said discharge device conductive including a source of direct current. and a winding linked bythe varying flux.

13. In apparatus for. theacceleration of charged particles in an. orbital path by the productionof a cyclically varying flux which links the path to accelerate the particles and" establishes amagnetic field to constrain the particles to the path, the combination which comprises a source of charged particles adjacent the path and effective when energized to inject charged particles into the path, means for energizing said source with energy pulses proportional to the magnitude of the varying flux in response to a triggering Voltage; a winding having a magnetically sa-turable corelinked by the varyingflux to generate aperiodic voltage: for triggering said means in timed relation to the varying flux, and currentsupp y means connected. to: said winding for magnetically biasing said: core toalterzthe, time at which. the periodic triggering. voltagesisseneratcd including a. source; of; cyclica-llysvarying current having a constant peakzlma'gnitudehand a. frequency equal to the frequency of the-,cycli: cally varying flux and a: winding. linked: by the varyingfiux.

1,4. In apparatus for the. acceleration: of charged particles in an. orbital path by, theprcs duction of alcyclically varying flux;which;links the path to accelerate the particles and estab:'- l-ishes a: magneticfie-ld to constrairrthe particles to the, path, the combination: which comprisesza source oi' chargedparticlesadjacent'the path and effective. when. energizedlto inject i charged pare ticies into the patln means;forrenergizing-"said source: with 7 energy" 'pulsesaof-z; varying. magnitude inresponse to a triggeringvoltageincludirig 'a first winding link'edby theiva-rying fluxztc. supply energy for: the pulse-sin proportionito stheamagnii-t tude of the varying flux, alsecondwindingjhaving a magnetically saturable core linked by; the. varying fiuxzto generate a periodic: voltage: for "trig gering said means in timed relation tothe varying flux, and current supplying means connected to saidsecond winding for magnetically biasing. said core to alter the time atwhich the periodic triggeringvoltage is generated including a source of cyclically varying: current having arconstantipeak magnitude and a frequency equal to the frequency of the cyclically varying flux'and a current-conducting circuit energized. by said.v firs winding.

15. In apparatus for the acceleration of charged particles in an orbital path by the production of a cyclically varyingflux whichv links the path to accelerate the. particles and establishes a magnetic field to constrain the particles to the path, the combination which comprises a, source of charged particles adjacent the path and. effective when energized to inject charged particles into the path, means for energizingsaid source with energy pulses of varying. magnitude in response to a. triggering voltage including a first winding linked by the varying flux to supply energy for the pulses in proportion to the magnitude of the flux, a second winding having a magnetically saturable corelinked by the varying flux to generate a periodic voltage for triggering said means in timed relation to the varying flux,

and current-supplying means. connected to said second winding for magnetically biasing said core to alter the time at which the periodic triggering' voltage is generated including a source of cyclically varying current having'a constant peak magnitude and a frequency equal to the frequency of'the cyclically varying flux and a winding linked by the varying flux. 7

16. In apparatus for the acceleration of charged particlesin an orbital path by the pro ducticn of a cyclically varying flux which links the path to accelerate the particles and establishes a magnetic field to constrain the particles to the path; the combination which comprises a source of charged particles adjacent the path and effective when energized to inject charged particles into the path; means for energizing said source including an energy-storing device, a winding linked by the varying flux and in circuit with a rectifier for charging said energy-storing device to a voltage proportional to the magnitude of the varying flux, and a grid-controlled gaseous discharge device in circuit; with. said energystoring device for discharging said energy-storing device when rendered conductiveby aitriggering signal to produce energy pulses for said source; means for rendering said discharge device conductive including a winding having a magnetically saturable core linked by the varying flux to produce a periodic voltage in said last named winding for triggering said discharge device in timed relation to the cyclical variations of the flux; and current-supplying means connected to said second named winding for magnetically biasing said core to alter the time at which said discharge device is rendered conductive including a source of cyclically varying current having a constant peak magnitude and a frequency equal to the frequency of the cyclically varying flux and a current-conducting circuit energized by said first named winding.

17. In apparatus for the acceleration of charged particles in an orbital path by the production of a cyclically varying flux which links the path to accelerate the particles and establishes a magnetic field to constrain the particles to the path; the combination which comprises a source of charged particles adjacent the path and efiective when energized to inject charged particles into the path; means for energizing said source including an energy-storing device, a winding linked by the varying flux and in circuit with a rectifier for charging said energystoring device to a voltage proportional to the magnitude of the varying fiux, and a grid-controlled gaseous discharge device in circuit with said energy-storing device for discharging said energy-storing device when rendered conductive by a triggering signal to produce energy pulses for said source; means for rendering said discharge device conductive including a winding having a magnetically saturable core linked by the varying flux to produce a periodic voltage in said last named winding for triggering said discharge device in timed relation to the cyclical variations of the flux; and current-supplying means connected to said second named winding for magnetically biasing said core to alter the timed relation of rendering said discharge device conductive including a source of cyclically varying current having a constant peak magnitude and a. frequency equal to the frequency of the cyclically varying flux and a winding linked by the varying flux.

THEODORE M. DICKINSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,297,305 Kerst Sept. 29, 1942 2,394,071 Westendorp 'Feb. 5, 1946 OTHER REFERENCES Kaiser, European Electron Induction Accelerators, Journal of Applied Physics, vol. 18, No. 1, January 1947, pages 1-18.

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