RuPAC2014 - List of Authors (Kurakin, V.G.)

Paper

Title

Page

Complex Shunt Impedance and Beam-RF Cavity Interaction

77

V.G. Kurakin
LPI, Moscow, Russia

Two approaches usually are used to describe beam-cavity interaction in accelerator based applications. The first one is electro dynamical and uses Maxwell equations to derive appropriate equations, field modes expressions being necessary to calculate field amplitudes excited by moving charges in the cavity. The other one uses LC circuit to derive appropriate equations for voltage amplitude induced in cavity by accelerated bunches, thin accelerating gap to some extent being not fully correctly defined representation in such approach. In this paper, the expressions are derived that describe beam-RF cavity interactions in terms of so called complex shunt impedance, strict electro dynamical approach being used in calculations. It is shown that complex shunt impedance module coincides completely with usual shunt impedance definition that up to now is used widely to describe rf cavity efficiency. The physical sense of its phase is given in the paper as well. Both complex shunt impedance module and its phase can be calculated or measured experimentally.

TUPSA19

Low Energy Electron Beam Line at Lebedev Physical Institute Accelerator Complex

V.G. Kurakin
LPI, Moscow, Russia

Microtron with the energy 7 MeV and beam current up to 30 mA is used as injector to electron synchrotron since 1974-th year. Several last years it is used to supply with electron beam the nuclear physics experiments as well. New experiments in the field of solid state physics are planed. Although there are two experimental halls at the accelerator complex environment experiments for the cost considerations where carried near to microtron, and this results in enhanced background. To make it possible to carry out several experiments at the same time in more comfortable conditions with minimum background the beam line from microtron to experimental hall with several end stations is under development. Followed are this beam line design features.

Paper	Title	Page
TUPSA18	Complex Shunt Impedance and Beam-RF Cavity Interaction	77
	V.G. Kurakin LPI, Moscow, Russia
	Two approaches usually are used to describe beam-cavity interaction in accelerator based applications. The first one is electro dynamical and uses Maxwell equations to derive appropriate equations, field modes expressions being necessary to calculate field amplitudes excited by moving charges in the cavity. The other one uses LC circuit to derive appropriate equations for voltage amplitude induced in cavity by accelerated bunches, thin accelerating gap to some extent being not fully correctly defined representation in such approach. In this paper, the expressions are derived that describe beam-RF cavity interactions in terms of so called complex shunt impedance, strict electro dynamical approach being used in calculations. It is shown that complex shunt impedance module coincides completely with usual shunt impedance definition that up to now is used widely to describe rf cavity efficiency. The physical sense of its phase is given in the paper as well. Both complex shunt impedance module and its phase can be calculated or measured experimentally.

TUPSA19	Low Energy Electron Beam Line at Lebedev Physical Institute Accelerator Complex
	V.G. Kurakin LPI, Moscow, Russia
	Microtron with the energy 7 MeV and beam current up to 30 mA is used as injector to electron synchrotron since 1974-th year. Several last years it is used to supply with electron beam the nuclear physics experiments as well. New experiments in the field of solid state physics are planed. Although there are two experimental halls at the accelerator complex environment experiments for the cost considerations where carried near to microtron, and this results in enhanced background. To make it possible to carry out several experiments at the same time in more comfortable conditions with minimum background the beam line from microtron to experimental hall with several end stations is under development. Followed are this beam line design features.