Abstract: A thin vacuum valve for particle accelerator beam lines comprising of a frame, a slide, a shaft, a first clamp, and preferably a second clamp, which is easily constructed from highly electrically conductive material and presents substantially smooth, flat surfaces towards adjacent particle accelerator component. The frame has first and second surfaces respectively facing toward the two adjacent particle accelerator system components, the first surface including a slide slot. A frame orifice extends through the frame between the first and second surfaces, preferably at the slide slot, and is positioned and sized on the frame to permit passage of a particle beam generated by the particle accelerator system along a beam line The slide is housed substantially within the slide slot and is movable between a first position and a second position along a slide axis. In the first position, the slide permits a particle beam to pass through the slide orifice and through the frame orifice along the beam line.

Abstract: Systems and methods for reducing dark current levels in a standing wave linear accelerator without sacrificing operating performance are described. In a radiation mode, the standing wave linear accelerator is operated to produce a pulsed therapeutic photon beam having a characteristic pulse width. In an electron mode, the standing wave linear accelerator is operated to produce a pulsed therapeutic electron beam having a characteristic pulse width that is shorter than the characteristic pulse width of the therapeutic photon beam. In some embodiments, assuming a uniform dark current level, the dark current level may be reduced in proportion with the beam pulse width reduction in the electron mode of operation. A system for implementing this therapeutic beam generation method also is described.

Abstract: A long life microwave electrodeless discharge lamp apparatus capable of preventing the generation of noise. The microwave electrodeless discharge lamp apparatus includes a magnetron having a magnetron tube and a yoke that surrounds the magnetron tube, a container housing at least the magnetron tube, a waveguide in which microwaves oscillated by the magnetron are propagated, an electrodeless discharge tube sealing luminescent materials excited by the microwaves to emit light, wherein a space surrounded by the yoke is communicated with the inside of the container, and wherein a fluid is sealed in the container. Thus, the magnetron tube is in a state in which it is immersed in the fluid.

Abstract: The closed electron drift plasma thruster uses a magnetic circuit to create a magnetic field in a main annular channel for ionization and acceleration, said magnetic circuit comprises: an essentially radial first outer pole piece; a conical second outer pole piece; an essentially radial first inner pole piece; a conical second inner pole piece; a plurality of outer magnetic cores surrounded by outer coils to interconnect the first and second outer pole pieces; an axial magnetic core surrounded by a first inner coil and connected to the first inner pole piece; and a second inner coil placed upstream from the outer coils. The thruster also comprises a plurality of radial arms included in the magnetic circuit, and a structural base which is separate from the magnetic circuit and which serves, amongst other things, to cool the coils.

Abstract: The disclosure relates to a particle accelerator which comprises two accelerating tubes as well as a charge-exchange channel, whereby the vacuum pump for evacuating from said charge-exchange channel gas particles injected therein is not connected to the high-voltage side but, via a vacuum tube, to the low-voltage side of the particle accelerator. This means a substantial simplification of the maintenance of the vacuum pump. In addition to that a motor and a generator are no longer required. By providing the vacuum pump with equipotential plates, which comprise pump holes arranged eccentrically round the center of the vacuum tube, the gas particles are in this configuration are accelerated while retaining the high breakdown strength.

Abstract: An electron beam accelerator utilizes a single microwave resonator holding a transverse-magnetic circularly polarized electromagnetic mode and a charged-particle beam immersed in an axial focusing magnetic field. The combined effect of the transverse-magnetic microwave fields and the axial magnetic field provide the electron beam with a helical shape and a rotational motion which allows the entire beam to be continually accelerated to high energies in a dc-like fashion. The use of the transverse-magnetic circularly polarized electromagnetic mode allows the resonant frequency to be independent of resonator length--allowing the resonator length to be selected to achieve desired particle acceleration. Using a transverse-magnetic rotating wave mode, TM.sub.110, allows the cavity frequency to be independent of cavity length and eliminates the need for bunched beams and short cavities while allowing the use of a spiraling moving beam.

Abstract: Disclosed is a novel composite magnet assembly for an insertion device of the Halbach type or hybrid type to be inserted into the linear part of, for example, an electron accelerator to generate a sine-curved periodical magnetic field in the air gap between two oppositely facing composite magnet block arrays. Different from a conventional magnet block assembly consisting of a plurality of permanent magnet blocks or alternate assembly of permanent magnet blocks and soft-magnetic pole pieces, the inventive magnet block assembly is composed of a plurality of oppositely facing composite magnet blocks each formed with a single base magnet block provided with a plurality of slits into which insert magnet pieces or insert pole pieces are inserted so that the dimensional accuracy in the length-wise direction of the magnet block assembly can be greatly decreased to improve the regularity of the periodical magnetic field.

Abstract: A device which improves the electrical and thermomechanical performance of an RF cavity, for example, in a disk-loaded accelerating structure. A washer made of polycrystalline diamond is brazed in the middle to a copper disk washer and at the outer edge to the plane wave transformer tank wall, thus dissipating heat from the copper disk to the outer tank wall while at the same time providing strong mechanical support to the metal disk. The washer structure eliminates the longitudinal connecting rods and cooling channels used in the currently available cavities, and as a result minimizes problems such as shunt impedance degradation and field distortion in the plane wave transformer, and mechanical deflection and uneven cooling of the disk assembly.

Abstract: In a radio-frequency accelerating system, a loop antenna is coupled with at least one of a plurality of magnetic core groups each including a plurality of magnetic cores or with at least one of the plurality of magnetic cores, and an impedance adjusting means is connected to the loop antenna. A relatively low voltage is applied to the impedance adjusting means. Therefore, the impedance adjusting means may be a circuit element having a low withstand voltage and hence the radio-frequency accelerating system can be formed to have a small construction.

Abstract: A ferrite core of the invention is useful for reducing the power loss of Ni--Cu--Zn ferrites, and so for particle accelerators, and power transformers. This core comprises a ferrite magnetic material containing as major components 47 to 50 mol % of iron oxide calculated as Fe.sub.2 O.sub.3, 10 to 25 mol % of nickel oxide calculated as NiO, 2 to 15 mol % of copper oxide calculated as CuO and 15 to 35 mol % of zinc oxide calculated as ZnO, and further containing as subordinate components 0.05 to 1.5 wt % of cobalt oxide calculated as CoO, 0.05 to 0.8 wt % of tungsten oxide calculated as WO.sub.3 and 0.03 to 0.5 wt % of bismuth oxide calculated as Bi.sub.2 O.sub.3, all based on the major components. Consequently, there is achieved a ferrite core having a power loss at 100.degree. C. of up to 210 kW/m.sup.3, and a power loss at 25.degree. C. of up to 140 kW/m.sup.3, as measured at f.multidot.Bm product=25 kTHz (f=1 to 10 MHz).

Abstract: An electron beam emitted from an electron gun enters into an accelerator 8 through a magnetic lens and is accelerated by a large number of accelerating tube discs within the accelerator, resonance cavities formed thereby and a magnetic field supplied from the outside. Then, it is focused by a focusing magnet and enters into an energy analyzer and scanned by a beam scanner, and is irradiated as a beam onto a sterilization goods item. On the outside of the accelerator there is disposed a cooling jacket for making uniform the thermal expansions of the resonance cavities due to thermal load.

Abstract: A coupled cavity accelerator (CCA) accelerates a charged particle beam with rf energy from a rf source. An input accelerating cavity receives the charged particle beam and an output accelerating cavity outputs the charged particle beam at an increased energy. Intermediate accelerating cavities connect the input and the output accelerating cavities to accelerate the charged particle beam. A plurality of tunable coupling cavities are arranged so that each one of the tunable coupling cavities respectively connect an adjacent pair of the input, output, and intermediate accelerating cavities to transfer the rf energy along the accelerating cavities. An output tunable coupling cavity can be detuned to variably change the phase of the rf energy reflected from the output coupling cavity so that regions of the accelerator can be selectively turned off when one of the intermediate tunable coupling cavities is also detuned.

Abstract: The invention relates to a radio-frequency particle accelerator. First and second cylindrical inner conductors 4 and 5 are disposed on the axis of the particle beams from the particle beam entrance with an accelerating gap interposed between the inner conductors in a TM or TEM mode particle accelerating cavity. An end of the first inner conductor 4 and an end of the second inner conductor 5 are joined to base plates of an outer conductor 3 of the accelerating cavity to form an inductance and together with the capacitance across the gap to form a resonant cavity. In order to synchronize particle beams with the radio-frequency accelerating phases, a bunching gap 11 with an inductance is formed by forming slots 11a on the first inner conductor 4. Thus, a radio-frequency electric power for exciting the accelerating cavity 2 is automatically supplied to the bunching gap 11 through the inductive coupling.

Abstract: A dielectric-wall linear accelerator is enhanced by a high-voltage, fast e-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.

Abstract: A method for controlling a particle acceleration energy in a radio-frequency quadrupole accelerator, the method being particularly adapted for ion implantation in the process of manufacturing semiconductor devices, wherein the particle acceleration energy is varied without the necessity of changing the resonant frequency of the RFQ accelerator so that the final energy of the particles has a plurality of distinct energy having a lower value than the designed voltage.

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.

Abstract: A pair of magnetic field adjusting center rods are inserted in central portions of a pair of pole pieces of a magnet included in a cyclotron. One of the magnetic field adjusting center rods is provided with an ion source receiving hole and the other is provided with a magnetic field adjusting recess coaxially with the ion source receiving hole. The magnetic field adjusting center rods are provided at their ends facing each other with magnetic field correcting projections, respectively. The magnetic field correcting projections project toward each other to form pole faces facing each other with a small air gap. Thus, irregularities in a magnetic field created between the pole pieces are corrected so that the dispersion of ion beams and the distortion of an orbit of ions can be prevented.

Abstract: A method of bunching a charged particle beam including the step of generating an electric field during a certain time duration, the electric field being generally parallel to a travelling direction of the charged particle beam having a kinetic energy of 1 eV to 1 MeV, and an intensity of the electric field changing as a quadratic function of time. In addition to the waveform changing as the quadratic function, a waveform changing linearly may also be used. The linearly changing waveform may be superposed upon a waveform of a half period from phase .pi. to 2.pi. of a sine wave if the linearly changing waveform monotonously increases, or upon a waveform of a half period from phase 0 to .pi. of a sine wave if the linearly changing waveform monotonously decreases. Furthermore, the linearly changing waveform and the sine waveform may be superposed upon a waveform of a half period from phase 0 to .pi.

Abstract: Equipment for achieving uniformalization of energy and pulsing of a particle beam is installed in an accelerated charged particle-beam generator or particle-beam storage ring. For maximum efficiency, a CMC (cyclotron maser cooling) unit for achieving uniformalization of energy and pulsing of the particle beam is introduced to generate a coherent particle beam.

Abstract: In a method of generating radiation, a gas having a pressure equal to or greater than 10.sup.-9 Torr is introduced into an electron orbit in an electron storage ring. The gas is ionized by a circulating electron beam, and the electron beam is focused by ions to accumulate a large current electron beam. Also, a target is disposed on an electron orbit in the electron storage ring, and the electron beam circulating along the electron orbit is caused to hit the target, thereby generating a bremsstrahlung and high-intensity radiation.

Abstract: The invention provides a method and apparatus for generating large amplitude nonlinear plasma waves, driven by an optimized train of independently adjustable, intense laser pulses. In the method, optimal pulse widths, interpulse spacing, and intensity profiles of each pulse are determined for each pulse in a series of pulses. A resonant region of the plasma wave phase space is found where the plasma wave is driven most efficiently by the laser pulses. The accelerator system of the invention comprises several parts: the laser system, with its pulse-shaping subsystem; the electron gun system, also called beam source, which preferably comprises photo cathode electron source and RF-LINAC accelerator; electron photo-cathode triggering system; the electron diagnostics; and the feedback system between the electron diagnostics and the laser system. The system also includes plasma source including vacuum chamber, magnetic lens, and magnetic field means.

Abstract: In an electron storage ring apparatus comprising at least two bending magnet units for defining an electron beam orbit of an arc shape, each of the bending magnet units comprises D-shaped upper and lower coil members each of which has an arc-shaped portion. Upper and lower yokes have grooves for entirely receiving the D-shaped upper and the D-shaped lower coil members, respectively.

Abstract: In a gyrotron comprising a cathode with an emitter ring, an accelerating anode, a resonator, a collector, and an uncoupling conduit, an arrangement is disposed around the resonator which generates a solenoidal static axial magnetic constant field which, in the area of the resonator, assumes a predetermined wave form causing the electrons emitted from the cathode to move along a spiral path and which has varying localized strengths such that the electrons passing therethrough along the spiral path have, upon exiting the resonator area, only an insignificant transverse velocity component left, whereupon they are attracted by the collector which is precharged.

Abstract: An electron beam is generated in a packetized form defined by pulses having a duty cycle of less than 1:1000. Each pulse may have a width of approximately one microsecond (1 .mu.sec.) and may be separated by approximately one (1) second from the next pulse. The electrical beam may be accelerated, preferably linearly. The electrical beam may be modulated at a particular frequency (e.g. 3 gigahertz) by bunching the electrons during the beam acceleration. The electrons may be converted to photons (e.g. X-rays) by directing the electron beam to a target made from a suitable material (e.g. tungsten). The photons are then interacted with the electrical circuitry to produce photoelectrons. The photoelectrons impair the operation of the electronic circuitry by generating an electrical current in the electrical circuitry, generating capacitive charges in the circuitry and generating an electromagnetic field in the vicinity of the circuitry.

Abstract: A coupled-cavity drift-tube linac (CCDTL) combines features of the Alvarez drift-tube linac (DTL) and the .pi.-mode coupled-cavity linac (CCL). In one embodiment, each accelerating cavity is a two-cell, 0-mode DTL. The center-to-center distance between accelerating gaps is .beta..lambda., where .lambda. is the free-space wavelength of the resonant mode. Adjacent accelerating cavities have oppositely directed electric fields, alternating in phase by 180 degrees. The chain of cavities operates in a .pi./2 structure mode so the coupling cavities are nominally unexcited. The CCDTL configuration provides an rf structure with high shunt impedance for intermediate velocity charged particles, i.e., particles with energies in the 20-200 MeV range.

Abstract: A circular particle accelerator includes a twist element at one location in its ring lattice which interchanges horizontal and vertical betatron oscillations upon each particle passage. Two traversals of the ring are required to return the particle to a corresponding state, thus the accelerator is termed a "Mobius" accelerator. The resultant toggling between transverse oscillation modes causes the accelerator to have remarkable properties, very different and in important ways superior to a conventional circular accelerator. Beam brightness can be increased by increasing the strength of focusing elements in the lattice while still preserving large amplitude stability. Furthermore, the resulting round particle beams generated by the accelerator are shown to be robust against beam-beam interaction, thus permitting use of the accelerator with unseparated, counter-rotating particle beams.

Abstract: A drift tube linac incorporates rf-electric quadrupole focusing by employing drift tubes with only one drift-tube stem per particle wavelength and in which the lowest frequency RF cavity mode has a transverse magnetic field (TM.sub.010 -mode). Each drift tube comprises two separate electrodes that form a capacitor that couples to the axial electric field of the primary cavity mode. The electrodes operate at different electrical potentials, as determined by the RF fields in the cavity, and are supported by a single stem along the axis of a cylindrical cavity. Each electrode supports two fingers pointing towards the opposite end of the drift tube, forming a four fingered geometry that produces an RF quadrupole field distribution along its axis. The fundamental periodicity of the structure is equal to the particle wavelength (.beta..lambda.) where .beta. is the particle velocity in units of the velocity of light and .lambda. is the free space wavelength of the rf.

Abstract: A secondary coil forming a resonant circuit in cooperation with a quadrupole is composed of conductive tubes and cooled by feeding coolant such as pure water into the tubes which serve as coolant passages. This makes it possible to minimize thermal deformation of the secondary coil when a variable-frequency type radio-frequency quadrupole accelerator is driven with a large amount of power. As a result, variation of the resonant frequency of the resonant circuit, resulting from the deformation of the secondary coil, can be minimized. Consequently, a given ion acceleration ability can be provided. When a coolant passage for use in cooling the primary coil is included and coolant such as pure water is fed into the coolant passage, thermal deformation of the primary coil can be minimized. Thus, impedance matching with the resonant circuit can be maintained on a stable basis.

Abstract: An active RF cavity is defined by a conductive wall in which a plurality of solid state power amplifiers are mounted. The solid state power amplifiers induce an RF current at an inner surface of the wall to form an oscillating electromagnetic (EM) field within the cavity. Preferably, the power amplifiers are in the form of modules that contain a number of RF power chips. The structure operates as both a power combiner and a matching transformer and is powered by a relatively low voltage d.c. source. A high-amplitude field is generated using equipment that is more efficient and much lighter in weight than conventional equipment. Such a cavity may be applied in a drift tube linac, an RF quadrupole linac, a linac having aligned cavities, and in other types of particle accelerators, and as a high power RF amplifier with the EM waves piped out via a waveguide or a coaxial cable.

Abstract: Method and apparatus for accelerating charged particles in a compact two-beam accelerator including a high voltage diode which generates an annular intense electron beam and a pencil-shaped secondary beam. The annular beam is modulated and functions as a driver beam for the secondary beam. A focusing magnetic field created by external focusing magnetic field coils adjusts the radius of the annular beam within a plurality of resonant cavity structures of an accelerating portion of the accelerator such that the phase slippage of the secondary beam, with reference to the co-propagated driver beam, is corrected. Correction of the phase slippage results in a secondary beam that is continuously accelerated. The external magnetic field also controls the energy of the secondary beam. Such high energy charged particles are useful in a wide variety of applications, such as medical radiation therapy, sterilization of medical equipment, industrial materials processing, inspection and industrial ion implantation.

Abstract: A beam position monitor capable of detecting the exact position of a beam of charged particles even if the beam has a large cross sectional area with its beam center being deviated from the center of the monitor. A plurality of electrodes 4A through 4D are disposed in a vacuum chamber 3 for inducing voltages when a beam passes through the vacuum chamber. A first voltage ratio is determined based on the voltages at the respective electrodes induced by the beam to thereby detect the beam position. An antenna 10 is disposed in the vacuum chamber 3 at a beam path for inducing voltages at the respective electrodes. A second voltage ratio is determined based on the voltages at the respective electrodes induced by the antenna whereby the first voltage ratio is corrected by using the thus determined second voltage ratio. The antenna has a cross sectional area equal to or less than that of the beam.

Abstract: An ion removing device includes an ion inducing electrode provided in a vacuum container in a deflection portion of an electron accumulating ring along an inner peripheral wall of the vacuum container, an ion removing electrode provided in the vacuum container near each of ports of the defection portion of the electron accumulating ring, and a power source for applying a voltage to both the ion inducing electrode and the ion removing electrodes. An ion removing method includes the steps of inducing ions trapped by a potential generated by an electron beam to ports of a deflection portion of an electron accumulating ring by forming an electric field in a vacuum container in the deflection portion, and removing the ions which have been inducted to the ports of the defection portion.

Abstract: A toroidal cavity-type electron accelerator is provided with a pair of electron beam sources. The beams from the two sources are respectively injected into the accelerating cavity at the mid-plane thereof and at a point displaced from the mid-plane whereby the electrons comprising the beam injected on the mid-plane will be accelerated while the electrons comprising the beam injected at the off mid-plane location will be decelerated and contribute their energy to producing a field for accelerating the electrons of the other beam.

Abstract: A radio frequency quadrupole (RFQ), which is a combination of the standard 4-vane and 4-rod designs, with a window or windows cut through mid-portions of the normally solid vanes. The windows decrease the resonant frequency, minimize undesirable mode coupling in the RFQ and result in a smaller and more easily tuned accelerator.

Abstract: A particle accelerator has a transmission window formed of a thin homogeneous foil having a predetermined thickness and having a predetermined length, and when laid fiat as a sheet having a transverse dimension. The window is formed to have a locus of a curve in cross section along the transverse dimension such that a radius of curvature of at least a portion of the curve in cross section is less than the length of the transverse dimension. Longitudinal channel and tubular shapes are preferred. Window cooling by gaseous and liquid fluid flows is also described. A transmission window assembly and a particle beam accelerator having an efficient rugged accelerator tube structure are also described.

Abstract: A circular accelerator for extracting a charged-particle beam is arranged to increase displacement of the beam by the effect of the betatron oscillation resonance and increase the betatron oscillation amplitude of the particles, which have initially betatron oscillation within the stability limit for the resonance, to exceed the stability limit thereby extracting the particles exceeding the stability limit of the resonance.

Abstract: Electrostatic accelerator includes an accelerating column (20), a high voltage terminal (18) located at one end of said accelerating column and electric charge transport means, said transport means incorporating a high frequency accelerator such as a high frequency electron accelerator (54) able to supply an electron beam and means (56) for supplying the electron beam to the high voltage terminal, said electric charges being constituted by the electrons supplied by said high frequency accelerator.