RU2038708C1 - Accelerating unit for linear resonant ion accelerator having grid focusing - Google Patents

Abstract

FIELD: accelerators of ions. SUBSTANCE: focusing piece has two spaces with sign-inverse phases, first space is phasing, second space is focusing. additional grid is installed on phasing space in order to decrease defocusing forces. This results in possibility to increase region of longitudinal and transverse catching. EFFECT: increased value of ion current. 1 dwg

Description

 The invention relates to charged particle accelerators and can be used to create applied ion accelerators and for the reconstruction of existing accelerators in the national economy.

Known linear resonant ion accelerators, in which to ensure the stability of the movement of charged particles, accelerating structures with phase-variable focusing, HF quadrupole and grid [1] are used
The prototype of the invention is an accelerating structure for a linear resonant ion accelerator with a grid focusing, containing an RF resonator with drift tubes, the grids are fixed at the input ends of them. The disadvantage of this accelerator is the low current intensity of accelerated particles, not exceeding fractions of a milliampere. This is due to the fact that the region of the joint longitudinal and lateral stability in the accelerators of this type does not exceed ^60-80.

 The aim of the invention is to increase the current of accelerated particles by increasing the longitudinal and lateral stability.

1+(-1)ⁿ·

, где φ_s1 φ_s2 фазы пролета синхронной частицей центров первого и второго зазоров, рад φ_s1,φ_s2=φ_o±φ₁
β

, V скорость синхронной частицы, с скорость света.This goal is achieved by the fact that on the focusing period there are two drift tubes, differing in length, and the grids are installed on the output ends of the odd tubes, and the distance between the centers of the n-th and (n + 1) -th gaps changes according to the law:
L _n =

1 + (- 1) ⁿ

, where φ _s1 φ _{s2 of the} phase of passage of a synchronous particle of the centers of the first and second gaps, rad φ _s1 , φ _s2 = φ _o ± φ ₁
β

, V is the speed of a synchronous particle, with the speed of light.

 Thus, the focusing period has two gaps with alternating phases, phasing and focusing, and an additional grid is installed on the phasing gap to reduce the effect of defocusing forces. Since the signs that distinguish the claimed technical solution from the prototype have not been identified in other solutions, the authors conclude that the proposed solution meets the criterion of "significant differences".

 The drawing schematically shows part of the accelerating-focusing channel, where L is the focusing period.

 The accelerating structure contains an RF resonator with a drift tube 1, which, with the help of holders 2, is mounted on the walls of the resonator 3. The grids 4 are installed at the input ends of all the drift tubes and at the output ends of the odd drift tubes.

1+(-1)ⁿ·

, где φ_s1 φ_s2 фазы пролета синхронной частицей центров первого и второго зазоров, φ_s1,φ_s2=φ_o±φ₁
φ_o и φ₁ постоянная и переменная составляющие синхронной фазы;
β

, V скорость синхронной частицы, с скорость света,
обеспечивается существенное увеличение жесткости фазовых колебаний, что приводит к значительному (примерно в два раза) увеличению по сравнению с ускорителями с сеточной фокусировкой области продольного захвата. В то же время установка дополнительных сеток на входе в фазирующий зазор (φ_s1<0) приводит к тому, что эти зазоры перестают оказывать дефокусирующее воздействие. В результате возрастает жесткость поперечных колебаний.The accelerating structure works as follows. When excitation of the RF fields in the resonator 3 due to the choice of the law of variation of the distance between the centers of neighboring gaps
L _n =

1 + (- 1) ⁿ

, where φ _s1 φ _{s2 of the} phase of passage of a synchronous particle of the centers of the first and second gaps, φ _s1 , φ _s2 = φ _o ± φ ₁
φ _o and φ ₁ constant and variable components of the synchronous phase;
β

, V is the speed of a synchronous particle, with the speed of light,
a substantial increase in the rigidity of phase oscillations is provided, which leads to a significant (approximately two-fold) increase compared with accelerators with a grid focusing of the longitudinal capture region. At the same time, the installation of additional grids at the entrance to the phasing gap (φ _s1 <0) leads to the fact that these gaps cease to have a defocusing effect. As a result, the rigidity of transverse vibrations increases.

 Calculations show that with such a modification of the grid focusing, the regions of longitudinal and lateral stability turn out to be several times larger than in the accelerator with grid focusing.

Claims (1)

ACCELERATING STRUCTURE FOR A LINEAR RESONANCE ACCELERATOR OF IONS WITH NETWORK FOCUSING, containing an RF resonator with drift tubes, the grids are fixed at the input ends, characterized in that the grids are also mounted on the output ends of the odd tubes, and the distance L between the centers of the n-th tubes + 1) of the clearance varies according to the law:

Where

phases of passage by a synchronous particle of the centers of the first and second gaps, glad;

where φ _{0 is the} constant component of the synchronous phase, rad;
φ ₁ variable component of the synchronous phase, rad;
λ wavelength, cm;

v _n speed of the synchronous particle in the center of the n-th gap, m / s;
c is the speed of light, m / s.

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