US3193722A - Method and means for control of a pulsed beam of charge carriers - Google Patents

Method and means for control of a pulsed beam of charge carriers Download PDF

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Publication number
US3193722A
US3193722A US102528A US10252861A US3193722A US 3193722 A US3193722 A US 3193722A US 102528 A US102528 A US 102528A US 10252861 A US10252861 A US 10252861A US 3193722 A US3193722 A US 3193722A
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Prior art keywords
pulse
control
generator
acceleration
pulses
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Expired - Lifetime
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US102528A
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English (en)
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Opitz Wolfgang
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RTX Corp
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United Aircraft Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/24—Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for

Definitions

  • the primary object of this invention to provide an improved method .and means for control of the acceleration and control electrode potentials of an electron beam generating system to provide beam pulses accelerated through a constant potential.
  • means for applying a pulsated acceleration potential to the beam generating system may conveniently be a plurality of rectangularly-shaped pulses.
  • the application of rectangular pulses to the beam generating system through a transformer having a low frequency band pass will distort the leading and trailing edges of the pulse but will rather faithfully reproduce the crest of the pulse.
  • a control pulse which is preferably derived from the acceleration potential pulse, is applied to the control electrode of the elec tron beam generator to overcome the blocking bias thereon and release a beam.
  • the generated beam pulses can be carefully controlled. Each pulse is properly focussed since the applied acceleration potential does not vary during the pulse period.
  • the acceleration pulses may be generated and applied to the generator system through a pulse transformer which can be designed with a relatively low frequency band pass.
  • the pulse crests are then transformed with "ice relatively good fidelity even though the leading and trailing edges are somewhat distorted. Since the grid control pulses operate only during the central portion of the acceleration pulse, the distortion of the leading and trailing edges will not result in concomitant distortion of the beam pulses. In fact, in some applications, it is feasible to use a sinusoidally varying acceleration potential by dimensioning the control pulses so that the beam is produced only during the relatively flat peak of the sinusoidal wave.
  • FIG. 1 is a schematic diagram of a beam generating system in accordance with this invention
  • FIG. 2 is a schematic diagram of a beam generating system in accordance with another embodiment of this invention.
  • FIG. 3 is a plot of the acceleration waveforms in which amplitude is plotted along the axis of abscissa as a function of time plotted along the axis of ordinates;
  • FIG. 4 is a plot of control pulse waveforms in which amplitude is plotted along the axis of abscissa .as a function of time plotted along the axis of ordinates;
  • FIG. 5 is a plot of beam amplitude in which amplitude is plotted along the axis of abscissa as a function of time plotted along the axis of ordinates.
  • FIG. 1 there is shown an electron beam generator 1 comprising a cathode 2, a control electrode 3 and a grounded anode 4. Heating current is supplied to the cathode from source 5 which is energized by the trans former 6.
  • the acceleration potential consisting of a series of rectangular waves is generated in generator 7.
  • the acceleration pulses are applied to cathode 2 to periodically pulse the cathode negative with respect to the grounded anode 4.
  • the control grid 3 is biased with respect to the cathode 2 by unidirectional biasing source 8 which is supplied with electrical energy through an isolating transformer 9, the rimary of which is at ground potential, the secondary of which is at the potential of the bias on the electron beam generating elements.
  • pulse generator 10 serially coupled with bias source 8 between the cathode 2 and control electrode 3 of generator 1.
  • the pulse generator is at the bias voltage level and supplied with energy through isolating transformer 11, the primary of which is at the ground potential.
  • control pulses from the pulse generator 10 which are synchronized with respect to the acceleration pulses from source 7
  • a delay line 12 which couples the acceleration potential pulses from generator 7 and applies them to the pulse generator 19 through capacitor 13.
  • the generator 10 is locked to the operating frequency of the generator 7 and generates control pulses at a predetermined time subsequent to the generation of the control pulse generated by generator 7.
  • These control pulses have a shorter pulse width than the acceleration field pulses so that the electron beam is controlled by the width of the control pulse only.
  • the cathode 2 is biased positively with respect to the control electrode 3 as, for. example, by application of a positive 12.0-volt bias.
  • the beam generating system is so biased as to prevent the emission of an electron beam therefrom.
  • generator 7 When generator 7 is brought into operation, a pulse train will be applied to both the cathode and the control electrode. Despite the swing in potential of the two electrodes to follow the applied acceleration potential, the relative bias between the electrodes will be maintained to prevent beam emission.
  • the cathode would reach a voltage of -99.88 kv. while the control electrode would reach .a potential of l kv.
  • the same relative bias between cathode and control electrode is maintained thereby precluding the generation of electron beams.
  • control pulse generator 16 would deliver a train of control pulses to overcome the cathode-grid bias thereby to initiate the discharge of an electron beam.
  • the control pulse is delayed with respect to the application of the acceleration pulse by means of the delay element 12 and is dimensioned to have such a short pulse width as to terminate prior to the termination of the acceleration pulse.
  • the control pulse will control the beam generator system and the sharpness of the leading and trailing edges of the control pulse controls the sharpness of the electron beam pulse.
  • the bias source 8 and generator 10 are at the operating potentials of the generator 1.
  • the embodiment shown in FIG. 2 may advantageously be employed.
  • FIG. 2 there is shown a high voltage pulse transformer with bifilar secondary windings which is utilized to transmit both the acceleration pulse train and the control pulse train to the electron beam generator 1 having the same operating electrodes and the same identifying numerals as shown in FIG. 1.
  • a pulse generator 117 is provided and is coupled to the primary winding 16 of transformer 15 having bifilar secondary windings 18 and 19. Thus, the secondary voltage generated in the secondary windings 18 and 19 are at the same cyclic rate and phase. One terminal of the secondary winding 19 is grounded.
  • a direct voltage generator 20 is serially coupled with a pulse generator 21 between one terminal of winding 18 and ground. The other terminal of the secondary windings 18 and 19 are respectively coupled to the cathode 2 and control electrode 3 of beam generator 1.
  • the bias established by source 20 is maintained between the cathode and the control grid 3 even though both elements are varying in potential according to the pulse train applied thereto from generator 17 through transformer 15. This bias is established at a level to keep the beam blocked.
  • the control impulse generator 21 will apply a pulse train which will overcome the cathode-grid bias during its negative excursions.
  • the control pulses are keyed to the frequency of the pulse generator 17 but are delayed in phase with respect thereto by delay line 22.
  • the control pulses are applied to the control elements of generator 1 through the secondary winding.
  • both bifilar coils 13 and 19 are fully compensated so that they have no significant effect on the core of transformer 15. Therefore, the inductance of the coil is negligible and the control pulses pass through the secondary windings without inductive distortion of the leading and trailing edges of the pulses.
  • the beam control may be precisely and positively controlled.
  • FIG. 3 there is shown the acceleration pulse 26 generated in the generator 17.
  • the acceleration pulse 26 generated in the generator 17.
  • FIG. 4 there is shown a typical waveform of the control pulse 28 plotted to the same time scale as is FIG. 3.
  • the leading edge of the control pulse is delayed with respect to that of the acceleration pulse and the width of the control pulse is short with respect to the width of the acceleration pulse so that its trailing edge occurs proir to the trailing edge of the acceleration pulse.
  • FIG. 5 there is shown a plot of the electron beam plotted to the same time scale as FIGS. 3 and 4.
  • the beam current pulse 29 has a sharp leading and trailing edge since these are determined by the control pulse 23 of FIG. 4 and not by the acceleration pulses represented by dotted line 27, FIG. 5.
  • the crest is relatively flat, following the waveform of the acceleration pulse 27.
  • the amplitude of the beam current pulse 29 can be controlled by selection of the bias applied by generator 20.
  • a simple and efiicient system for the control of a pulsated electron beam generator system which systems are advantageously employed for material treatment, such as boring, drilling, soldering, welding or heat treatment of such materials.
  • This type of system may also be employed for electron microscopes when it is necessary to reduce object exposure or when it is desired to photograph the object with flash attachments.
  • Apparatus for pulse control of the beam of an electron beam generator having an anode, a cathode, and control electrodes comprising a bias source for biasing said cathode positively with respect to said control electrode with an amplitude sufficiently high to cut off said electron beam, an acceleration pulse generator to generate a pulse train, consisting of a plurality of rectangular acceleration pulses, means coupling said acceleration pulse generator to said electron beam generator to pulse said anode positively with respect to said cathode and control electrode during each acceleration pulse of said train, a control pulse generator to provide a control pulse train consisting of rectangular control pulses, each control pulse of which is shorter than each acceleration pulse, means for applying said control pulses to said cathode and control electrode of said beam generator to overcome said bias, and a delay line coupling said acceleration pulse generator to said control pulse generator to key said control pulse generator so that each of said control pulses is generated during an acceleration pulse at a predetermined time subsequent to the generation of an acceleration pulse and so that said control pulses are at the same pulse repetition rate as said acceleration

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Particle Accelerators (AREA)
  • Electron Sources, Ion Sources (AREA)
US102528A 1960-04-14 1961-04-12 Method and means for control of a pulsed beam of charge carriers Expired - Lifetime US3193722A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEZ7937A DE1110330B (de) 1960-04-14 1960-04-14 Verfahren und Anordnung zur Impulssteuerung des Strahlstromes eines Ladungstraegerstrahlgeraetes

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US3193722A true US3193722A (en) 1965-07-06

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US (1) US3193722A (en, 2012)
CH (1) CH394423A (en, 2012)
DE (1) DE1110330B (en, 2012)
GB (1) GB919006A (en, 2012)
NL (2) NL122125C (en, 2012)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3361928A (en) * 1962-11-28 1968-01-02 Hitachi Ltd Transformers having a plurality of secondary windings and charged particle sources of double pulsing system utilizing such transformers
US3394284A (en) * 1966-03-07 1968-07-23 Sanders Associates Inc Capacitive loads and circuits for providing pulsed operation thereof
US3482096A (en) * 1965-08-02 1969-12-02 Field Emission Corp High energy field emission electron radiation pulse generator,x-ray apparatus and system employing same
US3826889A (en) * 1970-10-12 1974-07-30 I Brukovsky System for automatic control of electron beam heating device
US4020318A (en) * 1975-01-24 1977-04-26 The Welding Institute Electron beam generators
US4066894A (en) * 1976-01-20 1978-01-03 University Of Virginia Positive and negative ion recording system for mass spectrometer

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4204900C2 (de) * 1992-02-19 1994-01-20 Messer Griesheim Gmbh Elektronenstrahlmaschine

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2482768A (en) * 1942-12-30 1949-09-27 Sperry Corp High-frequency modulating system
US2534571A (en) * 1947-07-10 1950-12-19 Cinema Television Ltd Circuit for cathode-ray tubes and method of operating the same
US2821655A (en) * 1955-06-27 1958-01-28 Gen Electric Bias for electron beam equipment
US2844757A (en) * 1956-07-02 1958-07-22 Gen Electric Bias for electron beam apparatus
US2853623A (en) * 1957-06-04 1958-09-23 Quentin A Kerns X-ray pulse generator
US2897400A (en) * 1956-10-24 1959-07-28 Gen Electric Adjustable bias for electron beam apparatus
US2912616A (en) * 1956-02-07 1959-11-10 Itt Pulsed-cathode electron gun

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2482768A (en) * 1942-12-30 1949-09-27 Sperry Corp High-frequency modulating system
US2534571A (en) * 1947-07-10 1950-12-19 Cinema Television Ltd Circuit for cathode-ray tubes and method of operating the same
US2821655A (en) * 1955-06-27 1958-01-28 Gen Electric Bias for electron beam equipment
US2912616A (en) * 1956-02-07 1959-11-10 Itt Pulsed-cathode electron gun
US2844757A (en) * 1956-07-02 1958-07-22 Gen Electric Bias for electron beam apparatus
US2897400A (en) * 1956-10-24 1959-07-28 Gen Electric Adjustable bias for electron beam apparatus
US2853623A (en) * 1957-06-04 1958-09-23 Quentin A Kerns X-ray pulse generator

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3361928A (en) * 1962-11-28 1968-01-02 Hitachi Ltd Transformers having a plurality of secondary windings and charged particle sources of double pulsing system utilizing such transformers
US3482096A (en) * 1965-08-02 1969-12-02 Field Emission Corp High energy field emission electron radiation pulse generator,x-ray apparatus and system employing same
US3394284A (en) * 1966-03-07 1968-07-23 Sanders Associates Inc Capacitive loads and circuits for providing pulsed operation thereof
US3826889A (en) * 1970-10-12 1974-07-30 I Brukovsky System for automatic control of electron beam heating device
US4020318A (en) * 1975-01-24 1977-04-26 The Welding Institute Electron beam generators
US4066894A (en) * 1976-01-20 1978-01-03 University Of Virginia Positive and negative ion recording system for mass spectrometer

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Publication number Publication date
DE1110330B (de) 1961-07-06
NL263539A (en, 2012)
GB919006A (en) 1963-02-20
CH394423A (de) 1965-06-30
NL122125C (en, 2012)

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