LINAC2014 - List of Authors (Savilov, A.V.)

Paper

Title

Page

Helical Waveguides for Short Wavelength Accelerators and RF Undulators

248

S.V. Kuzikov, A.V. Savilov, A.A. Vikharev
IAP/RAS, Nizhny Novgorod, Russia
A.V. Savilov
NNGU, Nizhny Novgorod, Russia

The short wavelength accelerating structure can combine properties of a linear accelerator and a damping ring simultaneously. It provides acceleration of straight on-axis beam as well as cooling of this beam due to the synchrotron radiation of particles. These properties are provided by specific slow eigen mode which consists of two partial waves, TM01 and TM11. The flying RF undulator introduces a high-power short pulse, propagating in a long helically corrugated waveguide where the -1st space harmonic with negative phase velocity is responsible for particle wiggling. High group velocity allows providing long interaction of particles with RF pulse. Calculations show that RF undulator with period 5 mm, undulator parameter 0.1 is possible in 1 GW 10 ns pulse at frequency 30 GHz. The eigen mode in a helical undulator might have 0th harmonic phase velocity equal to light velocity. Such wave can be excited by relativistic drive bunch in the waveguide where witness bunch follows after the drive bunch, wiggles in wakefields, and generates X-rays at whole waveguide length. Helical waveguides can also be used in order to channel low-energy bunches in RF undulator of THz FEL.

Poster MOPP083 [2.139 MB]

THPP084

Cyclotron-Undulator Cooling of Electron Beams

1041

S.V. Kuzikov, I.V. Bandurkin, A.V. Savilov
IAP/RAS, Nizhny Novgorod, Russia
A.V. Savilov
NNGU, Nizhny Novgorod, Russia

XFELs require high-quality electron beams which can be produced in damping rings. For XFEL, based on Compton scattering of laser light, instead of the damping ring we consider a new compact device where electrons move in the undulator with axial DC magnetic field. In this undulator electrons move near resonant condition, rotating with cyclotron frequency and wiggling at similar bounce frequency. Such undulator allows compensation of the initial velocity spread by perturbations of the longitudinal velocities caused by transverse wiggling. Calculation show that ~1% velocity spread of 5 MeV electron beam (typical for photoinjectors) can be reduced to ~0.01% at distance as long as 20 undulator periods. In the advanced scheme, where the described undulators alternate with sections of the cyclotron radiation, energy spread as small as 0.001% is reachable. Calculations show that this principle works also for high energy beams (100 MeV and more), where RF undulator instead of DC-magnet undulator is preferable.

Poster THPP084 [0.713 MB]

THPP084

Cyclotron-Undulator Cooling of Electron Beams

1041

S.V. Kuzikov, I.V. Bandurkin, A.V. Savilov
IAP/RAS, Nizhny Novgorod, Russia
A.V. Savilov
NNGU, Nizhny Novgorod, Russia

XFELs require high-quality electron beams which can be produced in damping rings. For XFEL, based on Compton scattering of laser light, instead of the damping ring we consider a new compact device where electrons move in the undulator with axial DC magnetic field. In this undulator electrons move near resonant condition, rotating with cyclotron frequency and wiggling at similar bounce frequency. Such undulator allows compensation of the initial velocity spread by perturbations of the longitudinal velocities caused by transverse wiggling. Calculation show that ~1% velocity spread of 5 MeV electron beam (typical for photoinjectors) can be reduced to ~0.01% at distance as long as 20 undulator periods. In the advanced scheme, where the described undulators alternate with sections of the cyclotron radiation, energy spread as small as 0.001% is reachable. Calculations show that this principle works also for high energy beams (100 MeV and more), where RF undulator instead of DC-magnet undulator is preferable.

Poster THPP084 [0.713 MB]

Paper	Title	Page
MOPP083	Helical Waveguides for Short Wavelength Accelerators and RF Undulators	248
	S.V. Kuzikov, A.V. Savilov, A.A. Vikharev IAP/RAS, Nizhny Novgorod, Russia A.V. Savilov NNGU, Nizhny Novgorod, Russia
	The short wavelength accelerating structure can combine properties of a linear accelerator and a damping ring simultaneously. It provides acceleration of straight on-axis beam as well as cooling of this beam due to the synchrotron radiation of particles. These properties are provided by specific slow eigen mode which consists of two partial waves, TM01 and TM11. The flying RF undulator introduces a high-power short pulse, propagating in a long helically corrugated waveguide where the -1st space harmonic with negative phase velocity is responsible for particle wiggling. High group velocity allows providing long interaction of particles with RF pulse. Calculations show that RF undulator with period 5 mm, undulator parameter 0.1 is possible in 1 GW 10 ns pulse at frequency 30 GHz. The eigen mode in a helical undulator might have 0th harmonic phase velocity equal to light velocity. Such wave can be excited by relativistic drive bunch in the waveguide where witness bunch follows after the drive bunch, wiggles in wakefields, and generates X-rays at whole waveguide length. Helical waveguides can also be used in order to channel low-energy bunches in RF undulator of THz FEL.
	Poster MOPP083 [2.139 MB]

THPP084	Cyclotron-Undulator Cooling of Electron Beams	1041
	S.V. Kuzikov, I.V. Bandurkin, A.V. Savilov IAP/RAS, Nizhny Novgorod, Russia A.V. Savilov NNGU, Nizhny Novgorod, Russia
	XFELs require high-quality electron beams which can be produced in damping rings. For XFEL, based on Compton scattering of laser light, instead of the damping ring we consider a new compact device where electrons move in the undulator with axial DC magnetic field. In this undulator electrons move near resonant condition, rotating with cyclotron frequency and wiggling at similar bounce frequency. Such undulator allows compensation of the initial velocity spread by perturbations of the longitudinal velocities caused by transverse wiggling. Calculation show that ~1% velocity spread of 5 MeV electron beam (typical for photoinjectors) can be reduced to ~0.01% at distance as long as 20 undulator periods. In the advanced scheme, where the described undulators alternate with sections of the cyclotron radiation, energy spread as small as 0.001% is reachable. Calculations show that this principle works also for high energy beams (100 MeV and more), where RF undulator instead of DC-magnet undulator is preferable.
	Poster THPP084 [0.713 MB]

THPP084	Cyclotron-Undulator Cooling of Electron Beams	1041
	S.V. Kuzikov, I.V. Bandurkin, A.V. Savilov IAP/RAS, Nizhny Novgorod, Russia A.V. Savilov NNGU, Nizhny Novgorod, Russia
	XFELs require high-quality electron beams which can be produced in damping rings. For XFEL, based on Compton scattering of laser light, instead of the damping ring we consider a new compact device where electrons move in the undulator with axial DC magnetic field. In this undulator electrons move near resonant condition, rotating with cyclotron frequency and wiggling at similar bounce frequency. Such undulator allows compensation of the initial velocity spread by perturbations of the longitudinal velocities caused by transverse wiggling. Calculation show that ~1% velocity spread of 5 MeV electron beam (typical for photoinjectors) can be reduced to ~0.01% at distance as long as 20 undulator periods. In the advanced scheme, where the described undulators alternate with sections of the cyclotron radiation, energy spread as small as 0.001% is reachable. Calculations show that this principle works also for high energy beams (100 MeV and more), where RF undulator instead of DC-magnet undulator is preferable.
	Poster THPP084 [0.713 MB]