RU2395936C1 - Method of generating accelerating voltage in charged particle resonance accelerator - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: proposed method consists in excitation of resonance oscillations in coaxial delay line and generation of accelerating voltage therein. Magnetic component of the fields is generated only inside every inductor coil of delay line. Electromagnetic oscillations are excited on the side of LV section of coaxial delay line by variable current I_BX=U_acc/p, where U_acc is amplitude of accelerating voltage, ρ is delay line wave impedance.

EFFECT: higher efficiency of converting excitation oscillator electromagnetic oscillations in accelerated charged particle power.

Description

The invention relates to accelerator technology and can be used to create resonant accelerators for industrial use, for example, for cleaning flue gases of industrial enterprises from harmful SO _x and NO _x oxides, modification and production of new materials, sterilization of medical instruments and food products, disinfection of medical, etc. . waste.

Resonant electron accelerators are known in which they use a method of generating an accelerating voltage, including excitation of resonant oscillations in a coaxial delay line, the inner conductor of which is made in the form of a cylindrical spiral using a magnetic flux of the primary winding, which is located outside the resonator (see "Multi-beam Electron Accelerator for Industrial Application "Proceedings of the European Particle Accelerator Conference, Viena, 26-30 June, 2000, p.2600; GVDolbilov, GIDolbilova, INIvanov, AVMazhulin, JINR, Dubna, Russia; T. Ruskov, INRNE, Sofia, Bulgaria; "Multi-beam Electron Accelerator for Radiation Processing", Proceedings of 2001 Particle Accele rator Conference, 2001, Hyatt Regency, Chicago, Illinois, USA, June 18-22, 2001, p.651; GVDolbilov, GIDolbilova, INIvanov, AVMazhulin, VNRazuvakin; Joint Institute for Nuclear Research, Dubna, 141980, Russia; "High Repetition Pulsed Accelerator for EB-Technology", Proceedings of a Symposium on Radiation Technology for conservation of the environment, 8-12 September 1997, p. 453, Zakopane, Poland. G.V. Dolbilov, G. I. Dolbilova, A. A. Fateev, I. N. Ivanov, N. I. Lebedev, A. V. Mazhulin, V. A. Petrov, I. M. Hohlov. Joint Institute for Nuclear Research, Dubna, Russian Federation; T. Ruskov, Institute of Nuclear Research and Nuclear Energy, P. Goranov, Technical University, Sofia, Bulgaria; "High Repetition Pulsed Accelerator for Industrial Application", Proceedings of the II Scientific Seminar in Memory of V.P. Sarantsev, Dubna, September 23-24, 1997, G.V.Dolbilov et al .; Multi-Beam Pulsed Accelerator for Electron Beam Prisessing, Proceedings of 6th European Particle Accelerator Conference, Stockholm, 22-26 June, 1998, p.2398, GVDolbilov, GIDolbilova, AAFateev INIvanov, NILebedev, AVMazhulin, VAPetrov , IMHokhlov, JINR, Dubna, Russia, T. Ruskov, INRNE, P. Goranov, TU, Sofia, Bulgaria). The working components of the magnetic fields of the spiral inner conductor and the primary winding are distributed along the axis of the accelerator, providing transformer coupling of the primary and secondary (high voltage) systems.

The closest in functional parameters is the method described in the work (see "Multi-beam Electron Accelerator for Industrial Application" Proceedings of European Particle Accelerator Conference, Viena, June 26-30, 2000, p.2600; GVDolbilov, GIDolbilova, INIvanov, AV Mazhulin, JINR, Dubna, Russia; T. Ruskov, INRNE, Sofia, Bulgaria) (prototype), in which resonant oscillations are excited in the coaxial delay line using the magnetic flux of the primary winding and form an accelerating voltage in it.

The disadvantage of such accelerators using the method of transformer coupling of low-voltage and high-voltage circuits is the presence of a high level of dissipation fields outside the accelerator and induction heating and power loss in electrically conductive nodes and parts of the accelerator, as well as in radiation protection elements, which leads to a loss of power and a decrease in the efficiency of way.

Resonant accelerators based on coaxial delay lines have a low resonant operating frequency (f _res ~ 10 kHz-100 kHz), which allows the use of modern semiconductor devices to excite resonant oscillations in them, which have greater durability, reliability and efficiency than the electrovacuum devices used to excite conventional volume resonators in resonant accelerators (f _res ~ 100 MHz-1000 MHz). However, the magnetic fluxes of the spiral inner conductor and the primary exciting winding induces currents in all the electrically conductive elements of the accelerator and require special conditions for the exciting magnetic flux of the primary winding to penetrate the accelerator body (vacuum casing), for example, the use of a dielectric casing and an external conductor in the form special open conductive screens.

The technical result of the invention is to increase the efficiency of converting the energy of electromagnetic waves of an exciting generator into the energy of accelerated charged particles by reducing the scattering fields, reducing induction heating in the electrically conductive nodes and parts of the accelerator, as well as in radiation protection elements.

The method consists in the fact that they excite resonant oscillations in the coaxial delay line and form an accelerating voltage, the magnetic component of the fields is formed only inside each inductance coil of the delay line, and electromagnetic oscillations excite with an alternating current I _in = U _accele / ρ from the low-voltage part of the coaxial delay line , where U _accele is the amplitude of the accelerating voltage, ρ is the wave impedance of the delay line, and the parameter of small losses in the resonance delay line α satisfies the condition

α = I _in U U _accele / Q ₀ , where U _accele is the specified value of the accelerating voltage, I _in is the excitation current, Q ₀ is the intrinsic quality factor of the delay line.

Distinctive features of the claimed method are as follows.

The magnetic component of the fields is formed only inside each inductance coil of the delay line. This allows to reduce the scattering fields, to reduce induction heating and power losses in the electrically conductive nodes and parts of the accelerator, as well as in radiation protection elements, which leads to an increase in the efficiency of conversion of the energy of electromagnetic waves of the exciting generator into the energy of accelerated charged particles.

Electromagnetic vibrations in the resonant delay line are excited by an alternating current I _in = U _accele / ρ from the low-voltage part of the coaxial delay line, where U _accele is the amplitude of the accelerating voltage, ρ is the wave impedance of the delay line. Closed magnetic fluxes generated by the current in the line are concentrated only inside the windings of the inductors and this allows the metal vacuum housing of the accelerator to be used as an external conductor of the coaxial delay line. The accelerating voltage U _accele and the excitation current I _in form in the ratio α = I _in · U _accele / Q ₀ , where Q ₀ is the intrinsic quality factor of the delay line. The smaller the parameter α, the smaller the amount of power loss in the delay line.

The technical result is an increase in the efficiency of converting the energy of electromagnetic waves of an exciting generator into the energy of charged particles by reducing the scattering fields, reducing induction heating and power loss in electrically conductive nodes and parts of the accelerator, as well as in radiation protection elements. The combination of all the essential features of the formula makes it possible to eliminate all magnetic fluxes outside each of the inductance coils of the delay line, to excite resonance in the line in the presence of a metal external conductor of the line, and to reduce power losses in the delay line itself.

List of illustrations

Figure 1. The scheme of the resonant accelerator.

Figure 2. Equivalent circuit of the resonant delay line and plot the voltage and current in the line.

One of the options for implementing the proposed method is the formation of the magnetic component of the fields in the toroidal coils, in which the magnetic field is concentrated only inside the toroids and there are no scattered fields outside the toroids.

Figure 1 shows a diagram of a device where (1) an all-metal accelerator case, which is the external conductor of the delay line, (2) toroidal inductors of the internal conductor of the delay line, (3) an exciting generator, (4) a feeder, (5) cathode system, (6) vacuum window system. The wave impedance of the line and the resonant frequency of the accelerator are equal ρ = (L / C) ^1/2 , respectively; f _res = (16LC) ^-1/2, where L - total inductance of the inner conductor, and C - the total capacitance between the inner and outer conductors of a delay line. For example, when using an exciting generator based on transistor switches, the wave impedance can lie in the range of 10-100 kOhm, and the resonant frequency of 10-100 kHz.

An equivalent circuit of the resonant delay line and the current and voltage diagrams of the line are shown in Fig. 2, where (1) the inductance of the toroidal coils of the delay line, (2) the capacitance of the line coils relative to the external conductor, (3) the line load due to the electron beam, (4 ) a transistor generator, (5) the internal impedance of the generator, (6) the current diagram, and (7) the voltage diagram in the delay line.

The method works as follows.

The coaxial delay line is excited by a generator whose internal impedance is much less than the line impedance. The electric line length is made equal to 1/4 of the length of the slow wave, L = λ / 4. In resonance, the current in the line changes according to the law I (z) = I _in · Cos kz, and the voltage increases according to the law U (z) = U _in Q · Sin kz = U _accele · Sin kz, where Q is the loaded quality factor of the line in resonance , k = 2π / λ, z is the distance from the low-voltage end of the line, L is the line length, λ is the wavelength in the delay line. The amplitudes of the exciting current to the low voltage end of the line, and the accelerating voltage on the high voltage end of _{the Start} correspond to the relation U = ρI _Rin, where ρ - the wave impedance of the delay line.

For example, in an installation developed on the basis of the proposed method and tested at the Joint Institute for Nuclear Research at a wave impedance of the line ρ = 80 kΩ, an excitation current I _in = 5 A is required to form an accelerating voltage U _accele = 400 kV

The total power consumed by the resonator is

P = (1/2) I ² _in r r _in ,

where I _in = U _accele / ρ is the amplitude of the current at the input to the resonator, U _accele is the specified voltage amplitude at the high-voltage end of the delay line, ρ is the wave impedance of the line, r _in is the input impedance of the resonator at the resonant frequency:

r _in = ρ ² / R _beam + r,

wherein R _sheaves - equivalent resistance of the load beam, r - resistive impedance inner and outer conductors.

Since the component of the total power due to the beam load is

P _beam = (1/2) (U ² _accele / R _beam )

The power component due to resistive losses is

P _pot = (1/2) (I _in U U _accele / Q ₀ ),

where Q ₀ = ρ / r is the intrinsic quality factor of the delay line.

Thus, for a given value of U _accele , to reduce power losses, not only an increase in the intrinsic Q factor of the delay line is required, but also a decrease in the current exciting line, which is achieved by appropriate selection of the wave impedance of the line ρ.

Claims (2)

1. A method of generating an accelerating voltage in a resonant accelerator of charged particles, which method comprises generating resonant oscillations in the coaxial delay line and generating an accelerating voltage there, characterized in that the magnetic component of the fields is formed only inside each delay line inductance coil, and electromagnetic oscillations excite from the low voltage portion of the coaxial delay line alternating current I = U _{Rin USH} / ρ, where U _USH - accelerating voltage amplitude, ρ - ling wave impedance and delay. 2. The method according to claim 1, characterized in that the parameter of small power losses α in the delay line satisfies the condition α = I _in · U _accele / Q ₀ , where U _accele is the accelerating voltage, I _in is the excitation current, Q ₀ is its own Q-factor of the delay line.

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