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D. Nguyen

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Last Name: Nguyen

Full Name: D. Nguyen

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5 papers

title: Photoinjector design for the LCLS

format: conference procceeding

conference: 23rd International Free Electron Laser Conference

year: 2002

16 authors: Bolton, P. R. | Clendenin, J. E. | Dowell, D. H. | M. Ferrario | Fisher, A. S. | Gierman, S. M. | Kirby, R. E. | P. Krejcik | Limborg, C. G. | Mulhollan, G. A. | D. Nguyen | D. T. Palmer | J. B. Rosenzweig | Schmerge, J. F. | L. Serafini | X. J. Wang

abstract: The design of the Linac Coherent Light Source assumes that a low-emittance, 1 nC, 10 ps beam will be available for injection into the 15 GeV linac. The proposed RF photocathode injector that will meet this requirement is based on a 1.6-cell S-band RF gun equipped with an emittance-compensating solenoid. The booster accelerator with a gradient of 25 MV/m is positioned at the beam waist coinciding with the first emittance maximum, i.e., the "new working point." The UV pulses required for cathode excitation will be generated by tripling the output of a Ti:sapphire laser system. Details of the design and the supporting simulations are presented. (12 References).

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title: New design study and related experimental program for the LCLS RF photoinjector

format: conference procceeding

conference: 2000 European Particle Accelerator Conference

year: 2000

11 authors: M. Ferrario | Bolton, P. R. | Clendenin, J. E. | Dowell, D. H. | Gierman, S. M. | M. E. Hernandez | D. Nguyen | D. T. Palmer | J. B. Rosenzweig | Schmerge, J. F. | L. Serafini

abstract: We report the results of a recent beam dynamics study, motivated by the need to redesign the LCLS photoinjector, that lead to the discovery of a new effective working point for a split RF photoinjector. We consider the emittance compensation regime of a space charge beam: by increasing the solenoid strength, the emittance evolution shows a double minimum behavior in the drifting region. If the booster is located where the relative emittance maximum and the envelope waist occur, the second emittance minimum can be shifted to the booster exit and frozen at a very low level (0.3 mm-mrad for a 1 nC flat top bunch), to the extent that the invariant envelope matching conditions are satisfied. Standing Wave Structures or alternatively Traveling Wave Structures embedded in a Long Solenoid are both candidates as booster linac. A careful measurement of the emittance evolution as a function of position in the drifting region is necessary to verify the computation and to determine experimentally the proper position of the booster cavities. The new design study and supporting experimental program under way at the SLAC Gun Test Facility are discussed.

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title: Photon beam diagnostics for VISA FEL

format: conference procceeding

conference: 1999 Particle Accelerator Conference

year: 1999

17 authors: A. Murokh | C. Pellegrini | J. B. Rosenzweig | Pedro Frigola | P. Musumeci | A. Tremaine | M. Babzien | Ben-Zvi, I. | Doyuran, A. | E. Johnson | Skaritka, J. | X. J. Wang | Van Bibber, K. A. | J. M. Hill | Le Sage, G. P. | D. Nguyen | M. Cornacchia

abstract: The VISA (Visible to Infrared SASE Amplifier) project is designed to be a SASE-FEL driven to saturation in the sub-micron wavelength region. Its goal is to test various aspects of the existing theory of self-amplified spontaneous emission, as well as numerical codes. Measurements include: angular and spectral distribution of the FEL light at the exit and inside of the undulator; electron beam micro-bunching using CTR; single-shot time resolved measurements of the pulse profile, using an auto-correlation technique and FROG algorithm. The diagnostics are designed to provide maximum information on the physics of the SASE-FEL process, to ensure a close comparison of the experimental results with theory and simulations. (9 References).

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title: A measurement of high gain SASE FEL induced electron beam micro-bunching using coherent transition radiation

format: conference procceeding

conference: 1999 Particle Accelerator Conference

year: 1999

9 authors: A. Tremaine | S. Anderson | Pedro Frigola | Hogan, M. | A. Murokh | C. Pellegrini | J. B. Rosenzweig | D. Nguyen | Sheffield, R.

abstract: Coherent transition radiation (CTR) was used to study the longitudinal modulations of an electron beam exiting the UCLA/LANL high gain SASE FEL. The induced longitudinal micro-bunching of the electron beam at the exit of the undulator was measured with a frequency domain technique using the CTR emitted when this beam strikes a thin conducting foil. Formalisms for both CTR and SASE theories are related using the simulation code GINGER in which the SASE FEL gain of the output radiation and the micro-bunching of the electron beam are given. Experimental results from the CTR measurement will show the limit of standard transition radiation theory is being approached and new analysis is needed. (8 References).

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title: Measured free-electron laser microbunching using coherent transition radiation

format: conference procceeding

conference: 20th International Free Electron Laser Conference

year: 1999

9 authors: A. Tremaine | J. B. Rosenzweig | S. Anderson | Pedro Frigola | Hogan, M. | A. Murokh | C. Pellegrini | D. Nguyen | Sheffield, R.

abstract: The microbunch distribution of an electron beam exiting a SASE free-electron laser has been measured using the emitted coherent transition radiation (CTR) produced from a thin aluminum foil placed at the end of the undulator. The wavelength of the coherent transition radiation is shown to be the same as the FEL wavelength, and thus a measure of the beam microbunch spacing. Also, the study of the CTR linewidth and angular acceptance of the radiation captured are shown to be derived from this coherent radiative process. Scattering effects on the forward emitted transition radiation from the electron beam traversing an aluminum foil are also considered. (11 References).

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title:	Photoinjector design for the LCLS
format:	conference procceeding
conference:	23rd International Free Electron Laser Conference
year:	2002
16 authors:	Bolton, P. R. \| Clendenin, J. E. \| Dowell, D. H. \| M. Ferrario \| Fisher, A. S. \| Gierman, S. M. \| Kirby, R. E. \| P. Krejcik \| Limborg, C. G. \| Mulhollan, G. A. \| D. Nguyen \| D. T. Palmer \| J. B. Rosenzweig \| Schmerge, J. F. \| L. Serafini \| X. J. Wang
abstract:	The design of the Linac Coherent Light Source assumes that a low-emittance, 1 nC, 10 ps beam will be available for injection into the 15 GeV linac. The proposed RF photocathode injector that will meet this requirement is based on a 1.6-cell S-band RF gun equipped with an emittance-compensating solenoid. The booster accelerator with a gradient of 25 MV/m is positioned at the beam waist coinciding with the first emittance maximum, i.e., the "new working point." The UV pulses required for cathode excitation will be generated by tripling the output of a Ti:sapphire laser system. Details of the design and the supporting simulations are presented. (12 References).
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title:	New design study and related experimental program for the LCLS RF photoinjector
format:	conference procceeding
conference:	2000 European Particle Accelerator Conference
year:	2000
11 authors:	M. Ferrario \| Bolton, P. R. \| Clendenin, J. E. \| Dowell, D. H. \| Gierman, S. M. \| M. E. Hernandez \| D. Nguyen \| D. T. Palmer \| J. B. Rosenzweig \| Schmerge, J. F. \| L. Serafini
abstract:	We report the results of a recent beam dynamics study, motivated by the need to redesign the LCLS photoinjector, that lead to the discovery of a new effective working point for a split RF photoinjector. We consider the emittance compensation regime of a space charge beam: by increasing the solenoid strength, the emittance evolution shows a double minimum behavior in the drifting region. If the booster is located where the relative emittance maximum and the envelope waist occur, the second emittance minimum can be shifted to the booster exit and frozen at a very low level (0.3 mm-mrad for a 1 nC flat top bunch), to the extent that the invariant envelope matching conditions are satisfied. Standing Wave Structures or alternatively Traveling Wave Structures embedded in a Long Solenoid are both candidates as booster linac. A careful measurement of the emittance evolution as a function of position in the drifting region is necessary to verify the computation and to determine experimentally the proper position of the booster cavities. The new design study and supporting experimental program under way at the SLAC Gun Test Facility are discussed.
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title:	Photon beam diagnostics for VISA FEL
format:	conference procceeding
conference:	1999 Particle Accelerator Conference
year:	1999
17 authors:	A. Murokh \| C. Pellegrini \| J. B. Rosenzweig \| Pedro Frigola \| P. Musumeci \| A. Tremaine \| M. Babzien \| Ben-Zvi, I. \| Doyuran, A. \| E. Johnson \| Skaritka, J. \| X. J. Wang \| Van Bibber, K. A. \| J. M. Hill \| Le Sage, G. P. \| D. Nguyen \| M. Cornacchia
abstract:	The VISA (Visible to Infrared SASE Amplifier) project is designed to be a SASE-FEL driven to saturation in the sub-micron wavelength region. Its goal is to test various aspects of the existing theory of self-amplified spontaneous emission, as well as numerical codes. Measurements include: angular and spectral distribution of the FEL light at the exit and inside of the undulator; electron beam micro-bunching using CTR; single-shot time resolved measurements of the pulse profile, using an auto-correlation technique and FROG algorithm. The diagnostics are designed to provide maximum information on the physics of the SASE-FEL process, to ensure a close comparison of the experimental results with theory and simulations. (9 References).
keywords:
Download \| View \| Details \| edit \| delete

title:	A measurement of high gain SASE FEL induced electron beam micro-bunching using coherent transition radiation
format:	conference procceeding
conference:	1999 Particle Accelerator Conference
year:	1999
9 authors:	A. Tremaine \| S. Anderson \| Pedro Frigola \| Hogan, M. \| A. Murokh \| C. Pellegrini \| J. B. Rosenzweig \| D. Nguyen \| Sheffield, R.
abstract:	Coherent transition radiation (CTR) was used to study the longitudinal modulations of an electron beam exiting the UCLA/LANL high gain SASE FEL. The induced longitudinal micro-bunching of the electron beam at the exit of the undulator was measured with a frequency domain technique using the CTR emitted when this beam strikes a thin conducting foil. Formalisms for both CTR and SASE theories are related using the simulation code GINGER in which the SASE FEL gain of the output radiation and the micro-bunching of the electron beam are given. Experimental results from the CTR measurement will show the limit of standard transition radiation theory is being approached and new analysis is needed. (8 References).
keywords:
Download \| View \| Details \| edit \| delete

title:	Measured free-electron laser microbunching using coherent transition radiation
format:	conference procceeding
conference:	20th International Free Electron Laser Conference
year:	1999
9 authors:	A. Tremaine \| J. B. Rosenzweig \| S. Anderson \| Pedro Frigola \| Hogan, M. \| A. Murokh \| C. Pellegrini \| D. Nguyen \| Sheffield, R.
abstract:	The microbunch distribution of an electron beam exiting a SASE free-electron laser has been measured using the emitted coherent transition radiation (CTR) produced from a thin aluminum foil placed at the end of the undulator. The wavelength of the coherent transition radiation is shown to be the same as the FEL wavelength, and thus a measure of the beam microbunch spacing. Also, the study of the CTR linewidth and angular acceptance of the radiation captured are shown to be derived from this coherent radiative process. Scattering effects on the forward emitted transition radiation from the electron beam traversing an aluminum foil are also considered. (11 References).
keywords:
Download \| View \| Details \| edit \| delete

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