EP3102009A1 - Accélérateur d'électrons d'énergie multiples - Google Patents

Accélérateur d'électrons d'énergie multiples Download PDF

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Publication number
EP3102009A1
EP3102009A1 EP15170721.3A EP15170721A EP3102009A1 EP 3102009 A1 EP3102009 A1 EP 3102009A1 EP 15170721 A EP15170721 A EP 15170721A EP 3102009 A1 EP3102009 A1 EP 3102009A1
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EP
European Patent Office
Prior art keywords
electron
kicker magnet
cavity
accelerator
magnet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP15170721.3A
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German (de)
English (en)
Inventor
Michel Abs
Willem Kleeven
Eric Forton
Joseph Bendahan
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Ion Beam Applications SA
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Ion Beam Applications SA
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Publication date
Application filed by Ion Beam Applications SA filed Critical Ion Beam Applications SA
Priority to EP15170721.3A priority Critical patent/EP3102009A1/fr
Priority to PCT/EP2016/062355 priority patent/WO2016193294A1/fr
Publication of EP3102009A1 publication Critical patent/EP3102009A1/fr
Withdrawn legal-status Critical Current

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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
    • H05H13/10—Accelerators comprising one or more linear accelerating sections and bending magnets or the like to return the charged particles in a trajectory parallel to the first accelerating section, e.g. microtrons or rhodotrons
    • 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
    • H05H7/00—Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
    • H05H7/02—Circuits or systems for supplying or feeding radio-frequency energy
    • 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
    • H05H7/00—Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
    • H05H7/06—Two-beam arrangements; Multi-beam arrangements storage rings; Electron rings
    • 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
    • H05H7/00—Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
    • H05H7/04—Magnet systems, e.g. undulators, wigglers; Energisation thereof
    • H05H2007/046—Magnet systems, e.g. undulators, wigglers; Energisation thereof for beam deflection

Definitions

  • the invention relates to an electron accelerator having a resonant cavity wherein the electrons are accelerated a plurality of times and according to successive passages through the cavity, increasing the energy of the electrons after each passage.
  • a typical example of such an accelerator is a Rhodotron® , which is an electron accelerator having a single coaxial cavity wherein the electrons are first injected and then accelerated transversally a plurality of times according to a trajectory having the overall shape of a flower ("Rhodos" means flower in Greek).
  • the invention also relates to a material detection system comprising such an electron accelerator and to a material irradiation system comprising such an electron accelerator.
  • Rhodotron® Such accelerators are known for example from US patent publication number US-5107221 , describing a Rhodotron® which typically includes the following subsystems:
  • Such accelerator may for example operate under a continuous wave (CW) mode, which means that, when in operation, RF power from the RF source is continuously applied to the cavity and the electron source injects electrons into the cavity by bunches at the same frequency as the RF frequency, which is typically about 100 MHz to 200 MHz for current commercial Rhodotrons®. Hence, a "continuous wave" of accelerated electrons is delivered at the electron beam output port of the accelerator.
  • CW continuous wave
  • Rhodotrons® such as those which have been commercialized by the applicant for instance, typically deliver beam energies up to 10 MeV, with maximum beam power ranging from 25 KW to 700 KW.
  • these kind of accelerators are currently used for detection and security purposes for instance, such as for the detection of forbidden or hazardous substances and goods (such as weapons, explosives, drugs , etc.) which are hidden in containers.
  • forbidden or hazardous substances and goods such as weapons, explosives, drugs , etc.
  • WO03043388 discloses for example a Rhodotron® which is adapted to deliver multiple electron beams at respectively different energies, such as 7 MeV and 10 MeV for example.
  • this accelerator since this accelerator has only a single electron source, it is not capable of delivering these two beams simultaneously but rather one after the other.
  • the 10 MeV beam is output at a first output port for as long as all deflection magnets are energized, so that the electrons are accelerated a maximum number of times through the cavity, whereas the 7 MeV beam is output at a second output port after turning off downstream deflection magnets and for as long as these downstream deflection magnets are kept off, so that the electrons are accelerated less than the maximum number of times through the cavity.
  • the switching time between the two energies is however too slow with this conventional technology. This switching time is also too slow for other applications such as for the irradiation of materials or substances with the electron beams.
  • an electron accelerator comprising:
  • An electron accelerator according to the invention is therefore capable of delivering at least two electron beams at respectively at least two different energies in a fast time-interlaced fashion.
  • the electron accelerator further comprises a control unit configured to repeatedly switch the kicker magnet ON and OFF. More preferably, the control unit is configured to repeatedly switch the kicker magnet ON and OFF with a minimum time between two successive ON states which is less than 1/10 sec, preferably less than 1/100 sec, more preferably less than 2/1000 sec.
  • the kicker magnet is configured to provide - when energized - a beam bending angle smaller than 90°, preferably a beam bending angle comprised between 1 °and 20°, more preferably a beam bending angle comprised between 3° and 15°. With such a small bending angle, the kicker magnet can be made small and can have fast switching capabilities.
  • Rhodotron® Such kind of accelerator, sometimes called a Rhodotron®, is particularly well suited to achieve the aforementioned object of the invention.
  • the kicker magnet is configured to deviate the electron beam away from said nominal path and towards the intermediate accelerator output while said kicker magnet is switched ON by the control unit.
  • Such a configuration requires indeed the least modifications to the design of a conventional accelerator.
  • the kicker magnet is the first deflection magnet in the sequence of deflection magnets.
  • the required beam deflection angle of the kicker magnet can be made smaller than with other configurations.
  • Fig.1 schematically shows an axial cross section of an electron accelerator (1) according to the invention and comprising :
  • Such an electron accelerator (1) is sometimes called a "Rhodotron®" and is basically well known in the art.
  • Other types of accelerators, such as recirculating Linacs for example, may also be used.
  • At least one of the beam deflectors (30) comprises a plurality of beam deflection magnets arranged in sequence.
  • Said plurality of beam deflection magnets comprises a kicker magnet (80) configured to deviate the electron beam (40) away from said nominal path towards an intermediate accelerator output (41 a) for use by an application such as those described hereafter for example (material detection or material irradiation).
  • the electron accelerator (1) preferably further comprises a control unit (90) configured to repeatedly switch said kicker magnet (80) ON and OFF.
  • the control unit (90) is configured to repeatedly switch said kicker magnet (80) ON and OFF with a minimum time between two successive ON states which is less than 1/10 sec, preferably less than 1/100 sec, more preferably less than 2/1000 sec.
  • Such control unit (90) may for example comprise a pulse generator and a current amplifier, the current amplifier being steered by the pulse generator and delivering a pulsed excitation current to the kicker magnet (current I k , as can be seen on Figs. 5a , 5b , 8a , and 8b ).
  • the control unit (90) may alternatively be a programmable current source.
  • An exemplary programmable current source is the GMW-231 HC bipolar current amplifier commercialized by GMW Associates, which allows for USB or direct analogue programming of the current output.
  • Fig.2 schematically shows a transversal cross section of the electron accelerator (1) of Fig.1 , and according to a first embodiment.
  • the outer cylindrical conductor (11) of the cavity (10) comprises four beam entry ports and four beam exit ports, as well as thee beam deflectors (30) arranged outside the cavity (10), each beam deflector (30) being configured to receive the electron beam from an exit port (15) of the cavity (10) and to redirect the electron beam according to a nominal path towards an entry port (16) of the cavity (10), as shown on Fig.2 .
  • the nominal path of the electron beam (40) is indicated by a dashed line starting from the electron source (20) and ending at the main accelerator output (42a).
  • the accelerator may comprise more than three beam deflectors (30) or less than three beam deflectors (30), and, accordingly, more or less than four entry and exit ports in the outer conductor (11).
  • one of the beam deflectors (30) comprises two beam deflection magnets arranged in sequence: a kicker magnet (80), followed by a main magnet (81).
  • the kicker magnet (80) and the main magnet (81) are preferably electromagnets.
  • the kicker electromagnet (80) may use either a standard iron-laminated yoke or a ferrite-based yoke, the latter being known to be more suitable at higher switching frequencies because it generates less Eddy currents.
  • the kicker magnet (80) is preferably placed in the straight path of the electron beam (40) after leaving the exit port (15) of the cavity (10) and is arranged and designed in such a way that, when it is switched OFF by the control unit (90), the electron beam (40) will simply pass through it without deviation and will continue its straight trajectory towards the main magnet (81) which will then redirect the electron beam (40) towards the corresponding entry port (16) of the cavity (10) for further acceleration into the cavity.
  • the kicker magnet (80) remains switched OFF
  • the electron beam (40) will continue its trajectory towards the main accelerator output (42a) and therefore make a total of four acceleration passes through the cavity (10) in the present example.
  • the main accelerator output (42a) will therefore deliver a second electron beam (42) at an energy corresponding to these four successive acceleration passes.
  • the kicker magnet (80) is furthermore arranged and designed in such a way that, when it is switched ON by the control unit (90), it will generate a magnetic field which will deviate the electron beam away from said nominal trajectory towards an intermediate accelerator output (41 a), as shown by a dashed-dotted line on Fig.2 .
  • the electron beam will make a total of only two acceleration passes through the cavity (10) in the present example.
  • the intermediate accelerator output (41 a) will therefore deliver a first electron beam (41) at an energy corresponding to these two successive acceleration passes.
  • This accelerator is therefore capable of delivering two electron beams at respectively two accelerator outputs (intermediate output and main output) and at respectively two different energies, in a fast time-interlaced fashion.
  • the main magnet (81), when energized, provides a total beam bending angle of 225°
  • the kicker magnet (80), when energized provides a beam bending angle much smaller than 225°.
  • the kicker magnet (80) is preferably configured to provide, when energized, a beam bending angle smaller than 90°, preferably a beam bending angle comprised between 1 °and 20°, more preferably a beam bending angle comprised between 3°and 15°.
  • main magnet (81) may be in one part, as shown on Fig.2 , or in several successive parts, as will be described in relation to Fig.4 for example.
  • Fig.2a schematically shows a transversal cross section of the electron accelerator of Fig.1 , according to a preferred first embodiment. It is similar to the embodiment shown on Fig.2 , except that, in this preferred first embodiment, the kicker magnet (80) and the main magnet (81) are arranged and configured in such a way that the first electron beam (41), i.e. the electron beam leaving the kicker magnet (80) when the kicker magnet (80) is ON, falls under the influence of the magnetic field generated by the main magnet (81).
  • the first electron beam (41) i.e. the electron beam leaving the kicker magnet (80) when the kicker magnet (80) is ON
  • the kicker magnet (80) and the main magnet (81) are arranged and configured in such a way that the first electron beam (41), passes between the poles of the main magnet (81) for at least a part of its trajectory for as long as the kicker magnet (80) is ON.
  • the kicker magnet (80) and the main magnet (81) are arranged and configured in such a way that the first electron beam (41), passes between the poles of the main magnet (81) for at least a part of its trajectory for as long as the kicker magnet (80) is ON.
  • Fig.2a one may for example make the poles of the main magnet wider than they are in the case of Fig.2 , and/or by placing the main magnet (81) closer to the kicker magnet (80).
  • the first electron beam (41) will be bent by said magnetic field of the main magnet after said first electron beam (41) has left the excited kicker magnet.
  • Such a preferred configuration allows to redirect the first electron beam (41) to a direction which is different than the direction it had when leaving the kicker magnet (80), yet without requiring extra beam bending magnets.
  • the main magnet therefore has a double function in this preferred first embodiment: it bends the electron beam back to the entry port (16) of the cavity for further acceleration into the cavity while the kicker magnet is OFF, and it deviates the electron beam to a different direction than the direction it had when leaving the kicker magnet while the kicker magnet is ON.
  • Fig.3 schematically shows a transversal cross section of the electron accelerator (1) of Fig.1 , according to a second embodiment.
  • This second embodiment is similar to the first embodiment, except that the kicker magnet (80) is in this case placed after (downstream of) the main magnet (81) instead of before (upstream of) the main magnet.
  • Fig.4 schematically shows a transversal cross section of the electron accelerator (1) of Fig.1 , according to a third embodiment.
  • This third embodiment is similar to the first embodiment, except that the main magnet is divided into two parts (81 a, 81 b) and except that the kicker magnet (80) is in this case placed in the beam path between these two parts of the main magnet.
  • the two parts (81 a, 81 b) of the main magnet are arranged symmetrically and each part provides a total beam bending angle of 112,5 °, but many other configurations in two or more parts of the main magnet may of course be used.
  • the kicker magnet (80) and the second part (81 b) of the main magnet (81) are preferably arranged and configured in such a way that the first electron beam (41), i.e. the electron beam leaving the kicker magnet (80) when the kicker magnet (80) is ON, falls under the influence of the magnetic field generated by the said second part (81 b) of the main magnet (81).
  • the kicker magnet (80) and the second part (81 b) of the main magnet (81) are arranged and configured in such a way that the first electron beam (41), passes between the poles of the second part (81 b) of the main magnet (81) for at least a part of its trajectory for as long as the kicker magnet (80) is ON.
  • Such a preferred configuration allows to redirect the first electron beam (41) to a direction which is different than the direction it had when leaving the kicker magnet (80), yet without requiring extra beam bending magnets.
  • the second part (81 b) of the main magnet (81) therefore has a double function in this preferred third embodiment: it bends the electron beam back to the entry port (16) of the cavity for further acceleration into the cavity while the kicker magnet is OFF, and it deviates the electron beam to a different direction than the direction it had when leaving the kicker magnet while the kicker magnet is ON.
  • Fig.5a shows exemplary time diagrams for various beam and magnet currents in case of the accelerators of Figs. 2 , 2a , 3 and 4 , when these accelerators operate in continuous wave (CW) mode.
  • CW continuous wave
  • the first time diagram shows the excitation current (I k ) of the kicker magnet (80) over time.
  • This excitation current is provided by the control unit (90).
  • the excitation current is periodic and has a frequency f k , but it may as well be aperiodic.
  • the second time diagram shows the electron beam current (I 0 ) at an output of the electron source (20). For clarity reasons, this diagram does not show a possible microstructure in this beam current.
  • the electron source (20) injects indeed electrons into the cavity (10) by bunches at the same frequency as the RF frequency, which is typically about 100 MHz to 200 MHz.
  • the third time diagram shows the electron beam current (I 1 ) at the intermediate accelerator output (41 a).
  • the fourth time diagram shows the electron beam current (I 2 ) at the main accelerator output (42a).
  • the electron beam current at the intermediate accelerator output (I 1 ) and at the main accelerator output (I 2 ) will also be periodic and at the same frequency f k .
  • the duty cycle of the excitation current (I k ) of the kicker magnet (80) will determine the pulse duration at the intermediate accelerator output (TP1) and at the main accelerator output (TP2).
  • Fig.5b shows exemplary time diagrams for various beam and magnet currents in case of the accelerators of Figs. 2 , 2a , 3 and 4 , when these accelerators operate in pulsed-mode.
  • a pulsed-mode accelerator has for example been described in patent publication number WO2014184306A1 , which is incorporated herein by reference.
  • the first time diagram shows the excitation current (I k ) of the kicker magnet (80) over time.
  • This excitation current is provided by the control unit (90).
  • the excitation current is periodic and has a frequency f k , but it may as well be aperiodic.
  • the second time diagram shows the electron beam current (I 0 ) at an output of the electron source (20). Again for clarity reasons, this diagram does not show a possible microstructure in this beam current.
  • the electron beam current is periodic and has a frequency f 0 with a pulse duration TP 0 , but it may as well be aperiodic.
  • the third time diagram shows the electron beam current (I 1 ) at the intermediate accelerator output (41 a).
  • the fourth time diagram shows the electron beam current (I 2 ) at the main accelerator output (42a).
  • the electron beam current at the intermediate accelerator output (I 1 ) and at the main accelerator output (I 2 ) will also be periodic and at the same frequency f k .
  • the pulse duration (TP 0 ) of the electron beam current (I 0 ) will determine the pulse duration at the intermediate accelerator output (41 a) and at the main accelerator output (42a).
  • the duty cycle of the excitation current (I k ) of the kicker magnet (80) will determine the interlacing patterns of the electron beam current (I 1 ) at the intermediate accelerator output (41 a) and the electron beam current (I 2 ) at the main accelerator output (42a).
  • Fig.6 schematically shows a transversal cross section of the electron accelerator (1) of Fig.1 , according to a fourth embodiment.
  • This fourth embodiment is similar to the first embodiment, except that the kicker magnet (80) is arranged and controlled differently.
  • the kicker magnet (80) is placed in the trajectory of the electron beam (40) leaving the exit port (15) of the cavity (10) and it is in this case arranged and designed in such a way that, when it is switched ON by the control unit (90), the electron beam will be deviated towards the main magnet (81) which will then redirect the beam towards the corresponding entry port (16) of the cavity (10) for further acceleration into the cavity.
  • the kicker magnet (80) remains switched ON, the electron beam will continue its trajectory towards the main accelerator output (42a) and therefore make a total of four acceleration passes through the cavity (10) in the present example.
  • the main accelerator output (42a) will therefore deliver a second electron beam (42) at an energy corresponding to these four successive acceleration passes, for as long as the kicker magnet (80) remains switched ON.
  • the kicker magnet (80) is furthermore arranged and designed in such a way that, when it is switched OFF by the control unit (90), the electron beam will simply pass through it without deviation and continue a straight trajectory towards the intermediate accelerator output (41 a), as shown by a dashed-dotted line on Fig.6 .
  • the electron beam makes a total of only two acceleration passes through the cavity (10) in the present example.
  • the intermediate accelerator output (41 a) will therefore deliver a first electron beam (41) at an energy corresponding to these two successive acceleration passes, for as long as the kicker magnet (80) remains switched OFF.
  • This electron accelerator is therefore also capable of delivering two electron beams at respectively two accelerator outputs (main output and intermediate output) and at respectively two different energies, in a fast time-interlaced fashion.
  • the kicker magnet (80) and the main magnet (81) are preferably arranged and configured in such a way that the first electron beam (41), i.e. the electron beam leaving the kicker magnet (80) when the kicker magnet (80) is OFF, falls under the influence of the magnetic field generated by the main magnet (81), so that the first electron beam (41) will be bent by said magnetic field after said first electron beam (41) has left the unexcited kicker magnet.
  • the kicker magnet (80) and the main magnet (81) are arranged and configured in such a way that the first electron beam (41), passes between the poles of the main magnet (81) for at least a part of its trajectory for as long as the kicker magnet (80) is OFF.
  • the poles of the main magnet wider than they are in the case of Fig.6 , and/or by placing the main magnet (81) closer to the kicker magnet (80).
  • the first electron beam (41) will be bent by said magnetic field of the main magnet after said first electron beam (41) has left the unexcited kicker magnet.
  • Fig.7 schematically shows a transversal cross section of the electron accelerator (1) of Fig.1 , according to a fifth embodiment.
  • This fifth embodiment is similar to the fourth embodiment shown in Fig.6 , except that the kicker magnet (80) is placed after (downstream of) the main magnet (81) in this case.
  • Fig.8a shows exemplary time diagrams for various beam and magnet currents in case of the accelerators of Figs. 6 and 7 , when these accelerators operate in continuous wave mode.
  • the order of the time diagrams and the symbols used are the same as in Fig. 5a .
  • Fig.8b shows exemplary time diagrams for various beam and magnet currents in case of the accelerators of Figs. 6 and 7 , when these accelerators operate in pulsed mode.
  • the order of the time diagrams and the symbols used are the same as in Fig. 5b .
  • control unit (90) is preferably configured to vary the time during which the kicker magnet (80) is switched ON and/or to vary the time during which the kicker magnet (80) is switched OFF.
  • a pulse width modulator can be used for this purpose for instance. This allows to change the duty cycle and hence the interlacing patterns at the accelerator outputs.
  • control unit (90) is configured to repeatedly switch the kicker magnet (80) ON and OFF in a periodic fashion at a switching frequency
  • control unit (90) is preferably adapted to vary said switching frequency
  • the RF source (50) is adapted to energize the cavity (10) at a nominal RF frequency which is higher than 50MHz and lower than 500 MHz.
  • An electron accelerator (1) may be used for various purposes. It may for example be used for the detection of hidden and/or forbidden and/or hazardous substances and/or goods - such as weapons, explosives, drugs , etc - from an image formed either directly by the accelerated electrons or indirectly, for example by X-rays produced by said electrons after hitting a metal target for instance. It may also be used for the irradiation of substances by the electron beams, for example for sterilization purposes, such as food sterilization.
  • Fig.9 schematically shows a part of a material detection system according to the invention. It comprises an electron accelerator (1) according to the invention as described herein and which is hence adapted to produce and output in a fast time-interlaced fashion:
  • the material detection system further comprises a first RX conversion target (102) and a second RX conversion target (102) arranged respectively in the paths of the first and second electron beams coming from respectively the main and the intermediate accelerator outputs.
  • An RX conversion target is for example a material plate which converts impinging energetic electrons into X-Rays by the so-called "Bremsstrahlung" effect.
  • the material detection system further comprises a first RX detector (110) and a second RX detector (120) arranged respectively in the paths of the X-rays generated respectively by the first and the second RX conversion targets (101, 102) when bombarded by respectively the first and second electron beams.
  • a container (500) - whose material content is to be inspected - may for example be moved in translation between the conversion targets and the detectors, as indicated by a plain arrow on Fig. 9 .
  • Analysis and/or imaging of the signals delivered by the RX detectors (110, 120) allows to detect materials contained into the container (500).
  • the material detection system may also comprise other known subsystems such as electron beam benders, scanners and/or shapers, which are not illustrated for the sake of clarity.
  • Fig.10 schematically shows a part of a material irradiation system according to the invention. It comprises an electron accelerator (1) according to the invention as described herein and which is hence adapted to produce and output in a fast time-interlaced fashion:
  • the first electron beam (41) is directed to a first material product to be irradiated (601), whereas the second electron beam (42) is directed to a second material product to be irradiated (602).
  • These material products (601, 602) may for example be food products, which will be sterilized after having been irradiated by the electron beams (41, 42). Complete irradiation of the material products may be achieved by moving these products across the electron beams or by scanning or spreading the electron beams over the products or by any other equivalent means.
  • the material irradiation system may also comprise other known subsystems such as electron beam benders, scanners and/or shapers, which are not illustrated for the sake of clarity.
  • an electron accelerator (1) may of course be envisaged.
  • only one of the beam deflectors (30) comprises a kicker magnet (80) and the accelerator comprises consequently two electron beam outputs - one intermediate output and one main output - providing two electron beams at respectively two different energies.
  • the invention nevertheless also provides an accelerator wherein more than one beam deflector (30) comprises a kicker magnet (80), thereby providing more than one intermediate output in addition to the main output (42a), and therefore being adapted to deliver more than two electron beams at respectively more than two different energies.
  • the control unit (90) is configured to repeatedly and alternatively switch these kicker magnets ON and OFF, with a minimum time between two successive ON states of a given kicker magnet which is less than 1/10 sec, preferably less than 1/100 sec, preferably less than 2/1000 sec.
  • preferably only one kicker magnet is switched OFF at a time by the control unit (90) in case of the embodiments of Figs. 6 and 7 .
  • the main magnet(s) (81, 81 a, 81 b) of a beam deflector (30) is (are) preferably kept permanently switched ON while the accelerator accelerates electrons towards any of its outputs (41 a, 42a), i.e. while the kicker magnet (80) is switched ON and OFF.
  • the main magnet(s) are those beam deflection magnets of a beam deflector (30) which are not kicker magnets (80). Switching the main magnet(s) ON and keeping them switched ON while the kicker magnet (80) is switched ON and OFF, may be performed by the control unit (90) which controls the kicker magnet(s) (80) or by any other control unit.
  • An advantage of this preferred feature is that the magnetic field(s) of the main magnet(s) can be stabilized once, generally at the start-up of the accelerator, and remain stable for the operation time of the accelerator, so that the switching rate between the different accelerator outputs will depend mainly on the switching rate capacity of the kicker magnet(s).
  • an electron accelerator having a resonant cavity (10), an electron source (20) for injecting a beam of electrons (40) into the cavity, an RF source (50) adapted to generate an electric field (E) into the cavity for accelerating the electrons (40) a plurality of times inside the cavity according to angularly shifted trajectories up to a main accelerator output (42a), and beam deflectors (30) arranged outside the cavity and configured to redirect outgoing electrons back into the cavity for further acceleration into the cavity.
  • At least one of the beam deflectors (30) comprises a plurality of deflection magnets arranged in sequence and including a kicker magnet (80) configured to deviate the electron beam from a nominal trajectory and towards an intermediate accelerator output (41 a).
  • the electron accelerator preferably also comprises a control unit (90), which is configured to repeatedly switch the kicker magnet ON and OFF with a minimum time between two successive ON states which is less than 1/10 sec, preferably less than 1/100 sec, more preferably less than 2/1000 sec.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Particle Accelerators (AREA)
EP15170721.3A 2015-06-04 2015-06-04 Accélérateur d'électrons d'énergie multiples Withdrawn EP3102009A1 (fr)

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EP15170721.3A EP3102009A1 (fr) 2015-06-04 2015-06-04 Accélérateur d'électrons d'énergie multiples
PCT/EP2016/062355 WO2016193294A1 (fr) 2015-06-04 2016-06-01 Accélérateur d'électrons à énergie multiple

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EP15170721.3A EP3102009A1 (fr) 2015-06-04 2015-06-04 Accélérateur d'électrons d'énergie multiples

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US10212799B2 (en) 2016-02-15 2019-02-19 Stangenes Industries, Inc. System and method for high power pulse generator
EP3661335B1 (fr) * 2018-11-28 2021-06-30 Ion Beam Applications Accélérateur d'électrons d'énergie variable

Citations (6)

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