SU1392646A1 - Method of determining maximum amplitudes of free radial oscillations of particles in phasotron - Google Patents

Abstract

The invention relates to an accelerator technique and can be used to increase the efficiency of the output of particles from an accelerator, to improve the quality of an expanded SP beam. The method for determining the maximum amplitudes of the radial free oscillations of the particles in the phasotron is as follows. Pre-accumulate accelerated particles in the intermediate orbit, then dump П on the internal target and determine the minimum required band of If, C-electrode of the stretching system (SR. Using the same CP, the accumulated P is brought to the area in this case, the minimum required frequency band and f are determined. The proportionality coefficient X is determined experimentally between the increment of the radius and the change in the frequency of the accelerating voltage, and the value of the maximum amplitude A is free x oscillation is determined from the expressions A 3C (f,) / K 1 where K - estimated compression ratio value P. The method allows to determine the maximum amplitude of free oscillations in the radial synchrocyclotron C "(A.

Description

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The invention relates to accelerator technology and can be used, for example, to increase the efficiency of particle extraction from an accelerator, to improve the quality of an extended beam, etc.

The purpose of the invention is to determine the maximum amplitudes of free radial oscillations in the phasotron.

This method of determining the amplitudes of free oscillations in the phasotron is based on the use of the relationship between the increment of the radius of the accelerated beam and the corresponding: we feel a change in the frequency of the revolution (or frequency of the accelerating voltage) and f.

The relationship between changes in the frequency of circulation and the radius of a particle during its acceleration is determined by the ratio

dr. С J- df 1 dt 2W dt K (n + l) Rf

The method of stretching a beam consists in pre-accumulation of accelerated particles in an intermediate orbit of radius R by turning off the amplitude of the accelerating voltage at the dual to the maximum energy the beam reaches and then slowing them down. acceleration with a separate accelerating C-electrode system.

At the same time, the frequency of the accelerating voltage — on the C-electrode — changes by a factor of 20-100 (inversely to the above-mentioned filling factor in the phasotron) slower than that of the main (dual) program.

The frequency range required for stretching a beam is determined by two components

D Kdf ,,, -t-df

 R

where R is the radius of the beam; p and K is the growth rate of the magnetic field and the autophasing parameter on this radius; f and --T- - accelerating frequency dc

the floor and its time derivative at the moment of passing by a beam of radius R; From 3.10 m / s.

As can be seen from (1) for small increments of radius 4 G, linearly related to d f. Therefore, if it were possible to measure the value of Af necessary for moving the beam along the radius by an amount equal to fnoKa of an unknown J amplitude of the radial oscillations, this would be equivalent to measuring the amplitude itself. The process of stretching the beam with the C-electrode of the stretching system represents such an opportunity.

The temporal microstructure of the beam in the phasotron is related to the pulse nature of this accelerator and is usually characterized by a filling factor, defined as the ratio of the pulse duration of the accelerated particles (dropped on the internal target or out of the chamber) to the period of the following pulses. For active accelerators, this coefficient is usually 0.01-0.05.

For many physical experiments, it is desirable to have beams of accelerated particles with as high a filling factor as possible (a beam extended in time).

0

The first component is lf proportional to the maximum amplitude.

5 free (betatron) oscillations A, the second depends on the radial size of the C-electrode separatrix. Coefficient K depends on how the expanded beam is used. If a

0 it is dropped to an internal target, then. If the stretched beam is output by the regenerative system of the output (as it is done on all existing phasotrons), then K l 1 due to the effect of beam compression during extraction.

The value of Af. is determined by the energy width of the accumulated beam and does not depend on the mode (internal or output beam).

Therefore, we determined experimentally the frequency band required for stretching the emitted beam df, K 4 f + a f, and the frequency band that is not necessary for stretching the beam to an internal target & f fj ,, + Л f (, we find 4f (Af ) / (lK).

The voltage generator on the C-electrode is usually a broadband high-frequency amplifier with a master oscillator, whose frequency program can be easily adjusted (such adjustment is necessary to get close to a uniform current distribution over time in an extended beam).

Zn values of L f, and df j magnitude of the maximum amplitude of free

fluctuations can be calculated by the formula

. K-1

where ES is the proportionality coefficient determined experimentally, m / Hz. This allows us to provide the maximum fill factor at the minimum frequency range of the C-electrode, which is necessary for our purposes. Thus, for the experimental determination of a f and dfj, no new devices are required; it is only necessary that the frequency band of the C-electrode generator is sufficient both for stretching the beam to the internal target and the extracted beam, l f as follows from (I) directly proportional to the maximum amplitude of free radial oscillations. The proportionality coefficient can be determined experimentally using the following procedure: the frequencies fj and f of the accelerating voltage of the main dual are determined, at which the beam arrives, respectively, on the radii R. and R, and finds

with coefficient of proportionality ES- (R, - Rj) / (fj).

Compiled by E.Gromov Editor A.Dolinich Tehred I.Veres

Order 1891/57

Circulation 832

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d. A / 5

392646

Ф о р м y h а

the invention

The method for determining the maximum amplitudes of the radial free oscillations of particles in the phasotron, characterized in that the previously accumulated beam is first dropped onto an internal target using a stretching system, and the minimum required frequency band A fy Hz of the stretching system of the system and then using the same stretching system, the accumulated beam is brought to the zone of action of the output system and removed from the chamber, the minimum necessary frequency band Afj, Hz, C-electrode of the stretching system is also determined, expert The proportionality coefficient between the increment of the radius and the frequency change of the accelerating voltage ZSm / Hz is experimentally determined, and the maximum amplitude of free oscillations is determined according to the expression

V

Afi- l.

20

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where K is the calculated value of the beam compression ratio.

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Claims (1)

A method for determining the maximum amplitudes of the radial free vibrations of particles in a phasotron, characterized in that the previously accumulated beam is first dumped onto the internal target using the stretching system and the minimum necessary frequency band D f _y Hz of the C-electrode of the stretching system is determined, and then using stretching the stacked beam system is adjusted to output system coverage and outputted from the camera, thus also defining the minimum required bandwidth Af ₂ Hz, stretching, experimental S-electrode ntalno determine the proportionality coefficient between radius and incrementally varying the frequency of the accelerating SEM / Hz voltage, and the maximum amplitude of free oscillations is determined according to the expression