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Varfolomeev, A. A.

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Last Name: Varfolomeev

Full Name: Varfolomeev, A. A.

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7 papers

title: An undulator with nonadiabatic tapering for the IFEL project

format: conference procceeding

conference: 23rd International Free Electron Laser Conference

year: 2002

6 authors: Varfolomeev, A. A. | Tolmachev, S. V. | T. V. Yarovoi | P. Musumeci | C. Pellegrini | J. B. Rosenzweig

abstract: We describe the design of a planar undulator with unusually strong tapering, for the inverse FEL experiment (on the IFEL experiment at the UCLA Neptune Lab. Presented at the 2001 Particle Accelerator Conference, June 18-22, 2001, Chicago, Illinois) to be carried out in Neptune Lab. (Nucl. Instr. and Meth. A 410 (1998) 437) at UCLA. A powerful TW CO_2 laser will be used to accelerate electrons up to 50-60 MeV in 50 cm long undulator. A strong undulator tapering is needed because of the short Rayleigh length of the laser beam. Both the magnetic field and the undulator period are tapered to provide synchronicity of the laser beam interaction with a captured electron bunch along the whole undulator length. The most critical part of the undulator is the region near the laser focus. The main characteristics of the IFEL, such as the percentage of trapped electrons, energy of accelerated electrons and sensitivity to the laser focus transverse position, are given. The general principles of the design of this undulator construction can also be useful for high efficiency FEL amplifiers of intense laser modes.

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title: Measurements of gain larger than 10(5) at 12 mu m in a self-amplified spontaneous-emission free-electron laser

format: unknown

year: 1998

14 authors: Hogan, M. J. | C. Pellegrini | J. B. Rosenzweig | S. Anderson | Pedro Frigola | A. Tremaine | Fortgang, C. | D. C. Nguyen | R. L. Sheffield | Kinross-Wright, J. | A. Varfolomeev | Varfolomeev, A. A. | Tolmachev, S. | R. Carr

abstract: We report measurements of very large output intensities corresponding to a gain larger than 10/sup 5/ for a single pass free-electron laser operating in the self-amplified spontaneous emission (SASE) mode at 12 mu m. We also report the observation and analysis of intensity fluctuations of the SASE radiation intensity in the high-gain regime. The results are compared with theoretical predictions and simulations. (18 References).

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title: The UCLA infrared free-electron laser

format: conference procceeding

conference: SPIE Conference on Intense Laser Beams

year: 1992

17 authors: J. W. Dodd | S. C. Hartman | S. Park | C. Pellegrini | J. B. Rosenzweig | Smolin, J. A. | Barletta, W. A. | D. B. Cline | R. K. Copper | J. Kolonko | J. G. Davis | G. Hairapetian | C. J. Joshi | Luhmann, N. C., Jr. | S. N. Ivanchenkov | A. S. Khlebnikov | Varfolomeev, A. A.

abstract: A compact 20 MeV linac with an RF laser-driven electron gun will drive a high-gain (10 cm gain length), 10.6 mu m wavelength FEL amplifier, operating in the SASE mode. FEL physics in the high-gain regime will be studied, including start-up from noise, optical guiding, sidebands, saturation, and superradiance, with emphasis on the effects important for future short wavelength operation of FELs. The hybrid undulator, designed and built at the Kurchatov Institute of Atomic Energy in the USSR has forty periods, each 1.5 cm long, the magnetic material is a hybrid combination of SmCo_5 blocks and Nd-Fe-B blocks, with vanadium-permendur yokes. The gap distance between pole-tips is fixed at 5 mm. On axis the peak value of the completed undulator's magnetic field was measured to be 7.3 kGauss (+/- 0.25%). Measurements during the conditioning phase of the RF gun for the electron beam's peak dark-current show 6 mA without the longitudinal magnetic focusing field in the gun and 34 mA with the focusing field active. The peak current from photoemission is calculated to be 200 A.

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title: The UCLA compact infrared free-electron laser

format: conference procceeding

conference: 13th International Free Electron Laser Conference

year: 1992

16 authors: J. W. Dodd | S. C. Hartman | S. Park | C. Pellegrini | J. B. Rosenzweig | D. B. Cline | G. Hairapetian | J. Kolonko | Smolin, J. A. | P. G. Davis | C. J. Joshi | Luhmann, N. C., Jr. | S. N. Ivanchenkov | A. S. Khlebnikov | Varfolomeev, A. A. | Barletta, W. A.

abstract: The authors present the status of a compact infrared free-electron laser, driven by a 20 MeV, S-band linac with a photoinjector. The 60 cm long hybrid undulator has a 1.5 cm period and a field on axis of 7.3 kG. The FEL will operate at 10.6 mu m as a high-gain amplifier, to study the high-gain FEL regime including the effects of self amplified spontaneous emission, optical guiding and saturation. The linac is the prototype of the plane-wave transformer. TDA simulation of the FEL shows a gain length of 10 cm, and a saturation power of 50 MW. (18 References).

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title: Large-field-strength short-period undulator design

format: conference procceeding

conference: 13th International Free Electron Laser Conference

year: 1992

6 authors: Varfolomeev, A. A. | S. N. Ivanchenkov | A. S. Khlebnikov | C. Pellegrini | Baranov, G. A. | Michailov, V. I.

abstract: A high-quality strong-field hybrid undulator has been designed for an infrared FEL project to be performed at UCLA. The primary magnetic flux is provided by C-shaped vanadium-permendur yokes and SmCo_5 magnets. An additional magnetic flux is supplied by thin NdFeB magnet blocks placed between the yoke poles. This magnet geometry provides a high saturation limit for the magnetic field in the gap area. With the 15 mm period and 5 mm gap a peak on-axis field of 7.3 kG has been achieved. The undulator contains 40 periods. The high accuracy of the yoke poles alignment along with the ability to move the thin permanent magnet blocks provides an on-axis magnetic field accuracy better than 0.5%. (9 References).

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title: Saturnus: the UCLA infrared free-electron laser project

format: conference procceeding

conference: 1991 Particle Accelerator Conference

year: 1991

17 authors: J. W. Dodd | S. C. Hartman | S. Park | C. Pellegrini | J. B. Rosenzweig | Smolin, J. A. | G. Hairapetian | J. Kolonko | Barletta, W. A. | D. B. Cline | J. G. Davis | C. J. Joshi | Luhmann, N. C., Jr. | S. N. Ivanchenkov | A. S. Khlebnikov | Lachin, Y. Y. | Varfolomeev, A. A.

abstract: A compact 20-MeV linac with an RF laser-driven electron gun will be used to drive a high-gain (10-cm gain length), 10.6- mu m wavelength FEL (free-electron laser) amplifier, operating in the SASE mode. Saturnus will mainly be used to study FEL physics in the high-gain regime, including start-up from noise, optical guiding, sidebands, saturation, and superradiance, with emphasis on the effects important for future short-wavelength operation of FELs. The primary magnetic flux is provided by C-shaped iron yokes, where between the poles thin blocks of neodymium-iron-boron magnets are placed to provide additional magnetic flux along the undulator axis. (9 References).

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title: Saturnus: the UCLA high-gain infrared FEL project

format: conference procceeding

conference: 12th International Free Electron Laser Conference

year: 1991

17 authors: F. Aghamir | Barletta, W. A. | D. B. Cline | J. W. Dodd | S. C. Hartman | T. C. Katsouleas | J. Kolonko | S. Park | C. Pellegrini | Terrien, J. C. | J. G. Davis | C. J. Joshi | N. C. Luhmann | D. B. McDermott | S. N. Ivanchenkov | Lachin, Y. Y. | Varfolomeev, A. A.

abstract: The authors present the status of Saturnus: an infrared FEL operating in the 10 mu m wavelength region, driven by a compact 20 MeV linac with a photoinjector, under construction at UCLA. The 1.5 cm period, 0.5 T peak-field undulator is being built at the Kurchatov IAE. The FEL is being designed to operate primarily in the self-amplified spontaneous emission mode. They plan to study the startup from noise, optical guiding, saturation, sidebands and superradiance, with emphasis on the effects important for future short-wavelength operation of FELs. The photoinjector follows closely the Brookhaven design. Electrons are injected into an accelerating section based on the plane-wave transformer design developed by Swenson at SAIC. Simulation of the linac and FEL show a gain length of 10 cm, and saturation power of 50 MW. (10 References).

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title:	An undulator with nonadiabatic tapering for the IFEL project
format:	conference procceeding
conference:	23rd International Free Electron Laser Conference
year:	2002
6 authors:	Varfolomeev, A. A. \| Tolmachev, S. V. \| T. V. Yarovoi \| P. Musumeci \| C. Pellegrini \| J. B. Rosenzweig
abstract:	We describe the design of a planar undulator with unusually strong tapering, for the inverse FEL experiment (on the IFEL experiment at the UCLA Neptune Lab. Presented at the 2001 Particle Accelerator Conference, June 18-22, 2001, Chicago, Illinois) to be carried out in Neptune Lab. (Nucl. Instr. and Meth. A 410 (1998) 437) at UCLA. A powerful TW CO_2 laser will be used to accelerate electrons up to 50-60 MeV in 50 cm long undulator. A strong undulator tapering is needed because of the short Rayleigh length of the laser beam. Both the magnetic field and the undulator period are tapered to provide synchronicity of the laser beam interaction with a captured electron bunch along the whole undulator length. The most critical part of the undulator is the region near the laser focus. The main characteristics of the IFEL, such as the percentage of trapped electrons, energy of accelerated electrons and sensitivity to the laser focus transverse position, are given. The general principles of the design of this undulator construction can also be useful for high efficiency FEL amplifiers of intense laser modes.
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title:	Measurements of gain larger than 10(5) at 12 mu m in a self-amplified spontaneous-emission free-electron laser
format:	unknown
year:	1998
14 authors:	Hogan, M. J. \| C. Pellegrini \| J. B. Rosenzweig \| S. Anderson \| Pedro Frigola \| A. Tremaine \| Fortgang, C. \| D. C. Nguyen \| R. L. Sheffield \| Kinross-Wright, J. \| A. Varfolomeev \| Varfolomeev, A. A. \| Tolmachev, S. \| R. Carr
abstract:	We report measurements of very large output intensities corresponding to a gain larger than 10/sup 5/ for a single pass free-electron laser operating in the self-amplified spontaneous emission (SASE) mode at 12 mu m. We also report the observation and analysis of intensity fluctuations of the SASE radiation intensity in the high-gain regime. The results are compared with theoretical predictions and simulations. (18 References).
keywords:
Download \| View \| Details \| edit \| delete

title:	The UCLA infrared free-electron laser
format:	conference procceeding
conference:	SPIE Conference on Intense Laser Beams
year:	1992
17 authors:	J. W. Dodd \| S. C. Hartman \| S. Park \| C. Pellegrini \| J. B. Rosenzweig \| Smolin, J. A. \| Barletta, W. A. \| D. B. Cline \| R. K. Copper \| J. Kolonko \| J. G. Davis \| G. Hairapetian \| C. J. Joshi \| Luhmann, N. C., Jr. \| S. N. Ivanchenkov \| A. S. Khlebnikov \| Varfolomeev, A. A.
abstract:	A compact 20 MeV linac with an RF laser-driven electron gun will drive a high-gain (10 cm gain length), 10.6 mu m wavelength FEL amplifier, operating in the SASE mode. FEL physics in the high-gain regime will be studied, including start-up from noise, optical guiding, sidebands, saturation, and superradiance, with emphasis on the effects important for future short wavelength operation of FELs. The hybrid undulator, designed and built at the Kurchatov Institute of Atomic Energy in the USSR has forty periods, each 1.5 cm long, the magnetic material is a hybrid combination of SmCo_5 blocks and Nd-Fe-B blocks, with vanadium-permendur yokes. The gap distance between pole-tips is fixed at 5 mm. On axis the peak value of the completed undulator's magnetic field was measured to be 7.3 kGauss (+/- 0.25%). Measurements during the conditioning phase of the RF gun for the electron beam's peak dark-current show 6 mA without the longitudinal magnetic focusing field in the gun and 34 mA with the focusing field active. The peak current from photoemission is calculated to be 200 A.
keywords:
Details \| edit \| delete

title:	The UCLA compact infrared free-electron laser
format:	conference procceeding
conference:	13th International Free Electron Laser Conference
year:	1992
16 authors:	J. W. Dodd \| S. C. Hartman \| S. Park \| C. Pellegrini \| J. B. Rosenzweig \| D. B. Cline \| G. Hairapetian \| J. Kolonko \| Smolin, J. A. \| P. G. Davis \| C. J. Joshi \| Luhmann, N. C., Jr. \| S. N. Ivanchenkov \| A. S. Khlebnikov \| Varfolomeev, A. A. \| Barletta, W. A.
abstract:	The authors present the status of a compact infrared free-electron laser, driven by a 20 MeV, S-band linac with a photoinjector. The 60 cm long hybrid undulator has a 1.5 cm period and a field on axis of 7.3 kG. The FEL will operate at 10.6 mu m as a high-gain amplifier, to study the high-gain FEL regime including the effects of self amplified spontaneous emission, optical guiding and saturation. The linac is the prototype of the plane-wave transformer. TDA simulation of the FEL shows a gain length of 10 cm, and a saturation power of 50 MW. (18 References).
keywords:
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title:	Large-field-strength short-period undulator design
format:	conference procceeding
conference:	13th International Free Electron Laser Conference
year:	1992
6 authors:	Varfolomeev, A. A. \| S. N. Ivanchenkov \| A. S. Khlebnikov \| C. Pellegrini \| Baranov, G. A. \| Michailov, V. I.
abstract:	A high-quality strong-field hybrid undulator has been designed for an infrared FEL project to be performed at UCLA. The primary magnetic flux is provided by C-shaped vanadium-permendur yokes and SmCo_5 magnets. An additional magnetic flux is supplied by thin NdFeB magnet blocks placed between the yoke poles. This magnet geometry provides a high saturation limit for the magnetic field in the gap area. With the 15 mm period and 5 mm gap a peak on-axis field of 7.3 kG has been achieved. The undulator contains 40 periods. The high accuracy of the yoke poles alignment along with the ability to move the thin permanent magnet blocks provides an on-axis magnetic field accuracy better than 0.5%. (9 References).
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title:	Saturnus: the UCLA infrared free-electron laser project
format:	conference procceeding
conference:	1991 Particle Accelerator Conference
year:	1991
17 authors:	J. W. Dodd \| S. C. Hartman \| S. Park \| C. Pellegrini \| J. B. Rosenzweig \| Smolin, J. A. \| G. Hairapetian \| J. Kolonko \| Barletta, W. A. \| D. B. Cline \| J. G. Davis \| C. J. Joshi \| Luhmann, N. C., Jr. \| S. N. Ivanchenkov \| A. S. Khlebnikov \| Lachin, Y. Y. \| Varfolomeev, A. A.
abstract:	A compact 20-MeV linac with an RF laser-driven electron gun will be used to drive a high-gain (10-cm gain length), 10.6- mu m wavelength FEL (free-electron laser) amplifier, operating in the SASE mode. Saturnus will mainly be used to study FEL physics in the high-gain regime, including start-up from noise, optical guiding, sidebands, saturation, and superradiance, with emphasis on the effects important for future short-wavelength operation of FELs. The primary magnetic flux is provided by C-shaped iron yokes, where between the poles thin blocks of neodymium-iron-boron magnets are placed to provide additional magnetic flux along the undulator axis. (9 References).
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title:	Saturnus: the UCLA high-gain infrared FEL project
format:	conference procceeding
conference:	12th International Free Electron Laser Conference
year:	1991
17 authors:	F. Aghamir \| Barletta, W. A. \| D. B. Cline \| J. W. Dodd \| S. C. Hartman \| T. C. Katsouleas \| J. Kolonko \| S. Park \| C. Pellegrini \| Terrien, J. C. \| J. G. Davis \| C. J. Joshi \| N. C. Luhmann \| D. B. McDermott \| S. N. Ivanchenkov \| Lachin, Y. Y. \| Varfolomeev, A. A.
abstract:	The authors present the status of Saturnus: an infrared FEL operating in the 10 mu m wavelength region, driven by a compact 20 MeV linac with a photoinjector, under construction at UCLA. The 1.5 cm period, 0.5 T peak-field undulator is being built at the Kurchatov IAE. The FEL is being designed to operate primarily in the self-amplified spontaneous emission mode. They plan to study the startup from noise, optical guiding, saturation, sidebands and superradiance, with emphasis on the effects important for future short-wavelength operation of FELs. The photoinjector follows closely the Brookhaven design. Electrons are injected into an accelerating section based on the plane-wave transformer design developed by Swenson at SAIC. Simulation of the linac and FEL show a gain length of 10 cm, and saturation power of 50 MW. (10 References).
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