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W. Brown

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Last Name: Brown

Full Name: W. Brown

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2 papers

title: An Adjustable Permanent Magnet Quadrupole Final Focus System for Low Energy Experiments

format: conference procceeding

conference: 2003 Particle Accelerator Conference

year: 2003

7 authors: J. Lim | P. Frigola | J. B. Rosenzweig | S. Telfer | G. Travish | W. Brown | A. Tremaine

abstract: The final focus system for the Thomson X-ray scattering experiment termed PLEIADES (Picosecond Laser-Electron InterAction for Dynamic Evaluation of Structures) at LLNL demands ultra-high field gradient quadrupoles in order to focus initially small beams to 10-20 micron spot sizes. This scheme circumvents limitations due to chromatic aberrations and space-charge effects in this relatively low energy (<100 Mev) system. The final focus scheme is based on an ultra-high gradient (300T/m) quadrupole which employs the Halbach 16-piece, permanent magnet design. Use of this optimized goemetry, NdFeB material, and a small (4 mm) bore allows the desired field gradient, and few cm focal length, to be achieved. The adjustability of the focusing system is obtained by changing the relative longitudinal positions of sub-component focusing and defocusing magnets on precision movers. We present the results of RADIA 3D design simulations, and measurement of prototype magnets. We also discuss the results of beam dynamics simulations of the PLEIADES system using both envelope and tracking codes.

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title: Ultrafast materials probing with the LLNL Thomson X-ray source

format: conference procceeding

conference: 2002 Linear Accelerator Conference

year: 2002

24 authors: A. Tremaine | S. Anderson | W. Brown | C. Barty | R. Cauble | J. Crane | H. Cynn | C. Ebbers | D. Fittinghoff | D. Gibson | F. Hartemann | I. Jovanovich | J. Kuba | G. P. Le Sage | A. McMahan | R. Minich | J. Moriarty | B. Remington | D. Slaughter | P. Springer | F. H. Steitz | C. S. Yoo | J. B. Rosenzweig | T. Ditmire

abstract: The use of short laser pulses to generate very high brightness, ultra short (fs to ps) x-ray pulses is a topic of great interest. In principle, femtosecond-scale pump-probe experiments can be used to temporally resolve structural dynamics of materials on the time scale of atomic motion. The development of sub?ps x-ray pulses will make possible a wide range of materials and plasma physics studies with unprecedented time resolution. PLEIADES (Picosecond Laser Electron Interaction for Dynamic Evaluation of Structures), the Thomson scattering project at LLNL, will provide such a novel x-ray source of high power using short laser pulses and a high brightness, relativistic electron bunch. The system is based on a 5 mm-mrad normalized emittance photoinjector, 100 MeV electron RF linac, and a 300 mJ, 35 fs solid-state laser system. PLEIADES will produce ultra fast pulses with x-ray energies (60 keV) capable of probing into high-Z metals.

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title:	An Adjustable Permanent Magnet Quadrupole Final Focus System for Low Energy Experiments
format:	conference procceeding
conference:	2003 Particle Accelerator Conference
year:	2003
7 authors:	J. Lim \| P. Frigola \| J. B. Rosenzweig \| S. Telfer \| G. Travish \| W. Brown \| A. Tremaine
abstract:	The final focus system for the Thomson X-ray scattering experiment termed PLEIADES (Picosecond Laser-Electron InterAction for Dynamic Evaluation of Structures) at LLNL demands ultra-high field gradient quadrupoles in order to focus initially small beams to 10-20 micron spot sizes. This scheme circumvents limitations due to chromatic aberrations and space-charge effects in this relatively low energy (<100 Mev) system. The final focus scheme is based on an ultra-high gradient (300T/m) quadrupole which employs the Halbach 16-piece, permanent magnet design. Use of this optimized goemetry, NdFeB material, and a small (4 mm) bore allows the desired field gradient, and few cm focal length, to be achieved. The adjustability of the focusing system is obtained by changing the relative longitudinal positions of sub-component focusing and defocusing magnets on precision movers. We present the results of RADIA 3D design simulations, and measurement of prototype magnets. We also discuss the results of beam dynamics simulations of the PLEIADES system using both envelope and tracking codes.
keywords:
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title:	Ultrafast materials probing with the LLNL Thomson X-ray source
format:	conference procceeding
conference:	2002 Linear Accelerator Conference
year:	2002
24 authors:	A. Tremaine \| S. Anderson \| W. Brown \| C. Barty \| R. Cauble \| J. Crane \| H. Cynn \| C. Ebbers \| D. Fittinghoff \| D. Gibson \| F. Hartemann \| I. Jovanovich \| J. Kuba \| G. P. Le Sage \| A. McMahan \| R. Minich \| J. Moriarty \| B. Remington \| D. Slaughter \| P. Springer \| F. H. Steitz \| C. S. Yoo \| J. B. Rosenzweig \| T. Ditmire
abstract:	The use of short laser pulses to generate very high brightness, ultra short (fs to ps) x-ray pulses is a topic of great interest. In principle, femtosecond-scale pump-probe experiments can be used to temporally resolve structural dynamics of materials on the time scale of atomic motion. The development of sub?ps x-ray pulses will make possible a wide range of materials and plasma physics studies with unprecedented time resolution. PLEIADES (Picosecond Laser Electron Interaction for Dynamic Evaluation of Structures), the Thomson scattering project at LLNL, will provide such a novel x-ray source of high power using short laser pulses and a high brightness, relativistic electron bunch. The system is based on a 5 mm-mrad normalized emittance photoinjector, 100 MeV electron RF linac, and a 300 mJ, 35 fs solid-state laser system. PLEIADES will produce ultra fast pulses with x-ray energies (60 keV) capable of probing into high-Z metals.
keywords:
Download \| View \| Details \| edit \| delete

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