CW particle accelerator with low particle injection velocity
First Claim
1. An RF linear accelerator comprising:
- a charged particle source supplying charged particles having velocities substantially lower than the minimum particle injection velocity needed for efficient acceleration in a conventional RF linear accelerator which does not use drift tubes;
a first RF linear accelerator having one or more resonator cavities each with a drift tube therein coupled to receive charged particles from said charged particle source and structured to accelerate them from whatever velocity they arrived to a minimum velocity needed for efficient acceleration in an RF linear accelerator that does not use drift tubes;
a second RF linear accelerator which has one or more resonator cavities which do not employ drift tubes, said second RF accelerator coupled to receive charged particles output from said first RF linear accelerator said second RF linear accelerator structured for accelerating said charged particles arriving from said first RF linear accelerator up to a relativistic velocity;
an RF source of microwave energy coupled to said first and second RF linear accelerators so as to excite therein the TM010 mode; and
a coupling structure coupling said TM010 RF energy in said first linear accelerator to said second linear accelerator in such a way as to cause a phase change such that charged particles arriving from said first RF linear accelerator arrive at a first resonator cavity of said second RF linear accelerator at a time when the electric field of said TM010 mode in said first resonator cavity of said second RF linear accelerator is oriented in such a way as to accelerate said charged particles.
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Accused Products
Abstract
An RF linear accelerator using CW or low amplitude pulsed RF excitation which can efficiently accelerate charged particles from 0.1 C to relativistic velocities in excess of 0.9 C. A charged particle source feeds charged particles having velocities of about 0.1 C into a first type RF LINAC having a plurality of side coupled resonator cavities each having a drift tube in the middle. The RF length of the cavities is set relative to the velocity of the particles and the RF excitation wavelength such that the particles experience in-phase accelerating E fields in the gaps on either side of the drift tube and are shielded from decelerating E fields while inside the drift tubes. The RF coupling cavities establish sufficient phase change between adjacent resonators such that the particles arrive in the adjacent resonator cavities in synchronization with oscillations in the standing wave therein so as to experience further acceleration. The first RF LINAC accelerates the particles to 0.5 C approximately. The charged particles are then passed through a conventional RF LINAC with a CW source which is optimized to accelerate the particles from 0.5 C to relativistic velocities. A variable phase change RF coupler couples the RF between the first RF LINAC and the second RF LINAC such that a variable degree of synchronization can be achieved such that the energy of the particle beam exiting said second RF LINAC can be modulated by varying the phase change. A conventional CW RF LINAC is also disclosed with a duty cycle controlling system for operating the RF and charged particle sources with variable duty cycles so as to achieve control of average beam power and enable higher momentary beam energies than would otherwise be the case for CW LINACs.
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Citations
26 Claims
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1. An RF linear accelerator comprising:
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a charged particle source supplying charged particles having velocities substantially lower than the minimum particle injection velocity needed for efficient acceleration in a conventional RF linear accelerator which does not use drift tubes; a first RF linear accelerator having one or more resonator cavities each with a drift tube therein coupled to receive charged particles from said charged particle source and structured to accelerate them from whatever velocity they arrived to a minimum velocity needed for efficient acceleration in an RF linear accelerator that does not use drift tubes; a second RF linear accelerator which has one or more resonator cavities which do not employ drift tubes, said second RF accelerator coupled to receive charged particles output from said first RF linear accelerator said second RF linear accelerator structured for accelerating said charged particles arriving from said first RF linear accelerator up to a relativistic velocity; an RF source of microwave energy coupled to said first and second RF linear accelerators so as to excite therein the TM010 mode; and a coupling structure coupling said TM010 RF energy in said first linear accelerator to said second linear accelerator in such a way as to cause a phase change such that charged particles arriving from said first RF linear accelerator arrive at a first resonator cavity of said second RF linear accelerator at a time when the electric field of said TM010 mode in said first resonator cavity of said second RF linear accelerator is oriented in such a way as to accelerate said charged particles. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An RF linear accelerator comprising:
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a charged particle source; a first RF linear accelerator section structured to accelerate charged particles for velocities of approximately 0.1 C to 0.5 C using a CW or low amplitude pulsed RF source and drift tubes; a second RF linear accelerator section structured to accelerate charged particles received from said first RF linear accelerator from velocities of approximately 0.5 C up to relativistic velocities of 0.9 C and above using a CW or low amplitude pulsed RF source; a CW or low amplitude RF source coupled to both said first and second RF liner accelerators to generate microwave signals which excite a TM010 standing wave in said first and second linear accelerators; and a coupling structure to couple said TM010 standing wave energy from said first to said second linear accelerator so as to cause sufficient phase change seen by charged particles entering said second RF linear accelerator from said first RF linear accelerator so as to cause further acceleration of said charged particles in said second RF linear accelerator.
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9. An RF linear accelerator comprising:
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means for supplying charged particles having a velocity of approximately 0.1 C; first means for receiving said charged particles and accelerating them from their velocity of arrival to a velocity of about 0.5 C using;
a CW or low pulse amplitude RF sourcesecond means for receiving charged particles accelerated by said first means and accelerating them from whatever velocity they arrived from said first means to relativistic velocities near the velocity of light using a CW or low pulse amplitude RF source; and means for supplying CW or low pulse amplitude RF energy to said first and second means.
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10. An RF linear accelerator comprising:
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a source of charged particles having a velocity which is too low for RF accelerators without drift tubes and CW RF sources to accelerate; a first RF LINAC coupled to receive said charged particles and having a structure including drift tubes configured so as to accelerate said particles from the velocity at which they arrive up to a velocity at which they can be accelerated by RF LINACs having no drift tubes and CW or low pulse amplitude RF sources; a second RF LINAC coupled to receive accelerated charged particles from said first RF LINAC and structured so as to accelerate said charged particles from whatever velocity at which they arrive up to relativistic velocities;
an RF source of either a CW or low pulse amplitude design;a power splitter coupling a portion of the RF power from said RF power source to each of said first and second RF LINACs to excite a standing wave therein and for providing a relative phase shift between the output of said first RF linear accelerator and the input of said second RF linear accelerator so as to maintain synchronization. - View Dependent Claims (11, 12, 13, 14)
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15. A process for accelerating charged particles comprising:
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providing charged particles having a velocity which is too low to accelerate in RF LINAC resonators without drift tubes using a CW RF source; passing said charged particles through a CW standing wave pattern in one or more first type resonator cavities each having a drift tube therein and coupled by RF coupling cavities such that said charged particles are, in each first type resonator cavity, subjected to accelerating electric fields in the gaps on either side of each drift tube and shielded from decelerating electric fields while travelling through said drift tubes; passing said charged particles through a CW standing wave in one or more second type resonator cavities without drift tubes and RF coupled by coupling cavities such that said charged particles arrive at an input of the first of said second type resonator cavities in predetermined degree of synchronization with oscillations of said standing wave such that said charged particles are accelerated to relativistic velocities. - View Dependent Claims (16)
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17. An RF linear accelerator comprising:
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a charged particle source supplying charged particles having velocities substantially lower than the minimum particle injection velocity needed for efficient acceleration in a conventional RF linear accelerator which does not use drift tubes; a first RF linear accelerator having one or more resonator cavities each with a drift tube therein coupled to receive charged particles from said charged particle source and structured to accelerate them from whatever velocity they arrived to a minimum velocity needed for efficient acceleration in an RF linear accelerator that does not use drift tubes; a second RF linear accelerator which has one or more resonator cavities which do not employ drift tubes, said second RF accelerator coupled to receive charged particles output from said first RF linear accelerator, said second RF linear accelerator structured for accelerating said charged particles arriving from said first RF linear accelerator up to a relativistic velocity; a CW RF source of microwave excitation energy in the form of an RF waveform coupled to said first and second RF linear accelerators so as to excite therein the TM010 mode; and a coupling structure coupling said TM010 RF energy in said first RF linear accelerator to said second RF linear accelerator in such a way as to cause a phase change such that charged particles arriving from said first RF linear accelerator arrive at a first resonator cavity of said second RF linear accelerator at a time when the electric field of said TM010 mode in said first resonator cavity of said second RF linear accelerator is oriented in such a way as to accelerate or decelerate said charged particles at the choice of the operator; and switching means for enabling and disabling said CW RF source and said charged particle source so as to control the duty cycle of each so as to facilitate control of average output beam power by varying said duty cycles. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. An apparatus comprising:
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an RF linear accelerator structure; a CW RF source coupled to said RF linear accelerator so as to supply RF energy thereto when said CW RF source is enabled; a charged particle source coupled to supply charged particles to said RF linear accelerator when said charged particle source is enabled; a first switch coupled to enable or disable said CW RF source; a second switch coupled to enable or disable said charged particle source; and a beam energy/power controller coupled to said first and second switches so as to control the duty cycles for enabling and disabling of said CW RF source and said charged particle source so as to achieve a desired average output beam power from said RF linear accelerator. - View Dependent Claims (26)
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Specification