SU1600007A2 - Method of focusing and accelerating charged particles - Google Patents

Abstract

The invention relates to accelerator technology and can be used in linear accelerators with a high acceleration rate and high beam intensity. The aim of the invention is to increase the efficiency of phase and transverse focusing while simultaneously increasing the intensity of the accelerated beam, which is achieved by simultaneously injecting differently charged beams with certain parameters into the same region. Moreover, in the method there are no restrictions on the intensity associated with the space charge field. The limiting beam intensity will be determined by the collective effects of current loading, which must be taken into account when the power of the accelerated beam is comparable to the power of the RF generator.

Description

(.61) 1S58115

(21) 4228444 / 24-21

(22) 04/13/87

(46) 15.10.90. Bul Number 38

(71) Moscow Engineering Physics Institute

(72) E.C. Masunov

(53) 621.384.6 (088.8)

(56) USSR Copyright Certificate No. 1358115, cl. H 05 H 9/00, 1986.

(54) METHOD FOR FOCUSING AND ACCELERATION OF CHARGED PARTICLES

(57) The invention relates to accelerated. This technology can be used in linear accelerators with a high acceleration rate and high beam intensity. The aim of the invention is to increase the efficiency of phase and transverse focusing while simultaneously increasing the intensity of the accelerated beam, which is achieved by simultaneously injecting differently charged beams with certain parameters into the same area. Moreover, in the method there are no restrictions on the intensity associated with the space charge field. The ultimate beam intensity will be determined by the collective effects of the load current, which must be taken into account when the power of the accelerated beam is comparable to the power of the RF generator.

S

The invention relates to accelerator technology and can be used in the development of linear accelerators with a high acceleration rate and high beam intensity.

The aim of the invention is to increase the efficiency of phase and transverse focusing while simultaneously increasing the intensity of the accelerated beam.

This goal is achieved due to the fact that the known method of accelerating and focusing particle charges has one important feature — the change in the particle velocity on average during the transit time of a single period of the TU magnetostatic field is proportional to () 2, where Z is the particle backwardness; .M - relativistic particle mass. Therefore, if you inject simultaneously into the same area

Since the accelerating channel is oppositely charged beams consisting of particles with the same initial velocities and with the same Z / M ratio, the character of the averaged motion over the period for positive and negative charges will be the same. The grouping of continuous beams for opposite charges with any law of variation of the amplitudes of the magnetostatic and electromagnetic fields will pass in the same way if beams with the same initial emittances are injected into the same region of the accelerating channel. Clots of positive and negative charges of a charge are merged into one, which may turn out to be quasi-neutral if the magnitude of a beam current with a positive charge (1) is approximately equal to the magnitude of the current (I-) of a beam with a negative charge.

but

to

The Coulomb repulsion force is determined by the difference in the charge density of positive and negative particles, and will always be less than for each of the beams separately. In case of equality (1 +) (1-), the accelerated clot will be generally neutral and the Coulomb repulsive forces; without taking into account multipolar collective effects, it is possible not to take into account at all. This is one of the important advantages of the proposed method of acceleration and focusing in comparison with the acceleration in the RF field of the wave. So, in a structure with spatially homogeneous quadrupole focusing (POKF) or in a structure of the Alvarezital type, oppositely charged

I

thirty

bundles are grouped around different syi- 2Q chronic phases (q 5 (9 therefore clots with positive and negative charge) are spaced apart. Spatial charge compensation in this case is absent, and the magnitude 25 of the Coulomb repulsion will be the same as and for one bundle.

According to the proposed method, only neutral particles can emerge from the mode, acceleration and focusing, which form under the condition of the appearance of a bound state between particles (ions) of different signs. However, such events are unlikely because of the large relative velocity of the particles. Indeed, for each particle of a cpu-35, the trajectory is a collection of a slowly varying function and fast oscillations of the periodic magnetostatic and in the high-frequency fields. For oppositely charged particles under identical initial conditions, the mutually varying trajectories coincide, and the speeds of fast oscillations are opposite in sign and therefore always relatively large.

As an example of the implementation of the proposed method of focusing and accelerating charged particles, let us consider the simplest case of acceleration of hydrogen ions in the field of a TEM wave generated by a 50 two-wire line, and in a periodic one. In space, a magnetostatic field, which can be obtained with a flat magnetic undulator. If the plane in which the two-55 wire line is located is the antisymmetry plane along the magnetic field Bp

He donned a torus, provided that

45

d on the axis of the system, where E is the amplitude of the transverse component of the TEM wave, the charged particles will be focused and accelerated if the initial

 AO

thirty

Q 5

35 о50 ю -55

injection speed VJ C where

. 6 - TEM-wavelength, C - speed

, 9B,

Sveta. The second condition is g 1 d pl d t

-; on the axis is done automatically. At L in. 3 m; 0.045 m, we have V 1,5-102-s, which corresponds to the injection energy W 100 keV. If Ea is 90 keV / cm, the magnitude is BQ 2 T, and the maximum acceleration rate is l, 1 45 meV / m. The beam current Ippea-200-300 mA limiting in the Coulomb field. If a beam of H or H ions is injected along the axis separately with a current, for example, I 1 A, then due to the Coulomb defocusing, most of the particles will be lost in the acceleration process. If, however, two beams H and H with the same or similar initial parameters and with (I) e are simultaneously brought and injected to the injection site; (I)

45

then quasi-neutral clots will form and accelerate in the acceleration channel. Coulomb defocusing will be practically reduced to zero. The same task can be further simplified if, instead of two identical ionic sources H and H, take one source H s (1) 2. A, and at the entrance to the accelerating channel, set a stripping target with over-charge efficiency H in H 50%. Then, as before, quasi-neutral bunches will accelerate without loss. If at the output of the accelerator it is necessary to have only particles of the same sign (for example, H ions), this is easy to do by setting a recharging target at the end of the accelerator, with the help of which the remaining part of H ions can be converted to H.

Thus, according to the proposed method of acceleration and focusing, there are practically no restrictions on the intensity associated with the field of spatial charge. The limiting beam intensity is determined by the collective effects of the load current, which must be taken into account when the power of the accelerated beam is comparable to the power of the RF generator.

51600007.6

Claims (1)

The claims are injected simultaneously into one and the same The method of focusing and accelerating the same area is oppositely charged charged particles according to aut. No. 1358115, beams consisting of particles with the same difference in that, with initial initial speeds and with the same goal of increasing efficiency, the Z / M ratio, where Z is great and the phase focusing is the cause of the charge particles, M - rela tive increase in the number of accelerated particles, Whist mass of particles, kg.