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Amplitude variations on the Extreme Adaptive Optics testbed (open access)

Amplitude variations on the Extreme Adaptive Optics testbed

High-contrast adaptive optics systems, such as those needed to image extrasolar planets, are known to require excellent wavefront control and diffraction suppression. At the Laboratory for Adaptive Optics on the Extreme Adaptive Optics testbed, we have already demonstrated wavefront control of better than 1 nm rms within controllable spatial frequencies. Corresponding contrast measurements, however, are limited by amplitude variations, including those introduced by the micro-electrical-mechanical-systems (MEMS) deformable mirror. Results from experimental measurements and wave optic simulations of amplitude variations on the ExAO testbed are presented. We find systematic intensity variations of about 2% rms, and intensity variations with the MEMS to be 6%. Some errors are introduced by phase and amplitude mixing because the MEMS is not conjugate to the pupil, but independent measurements of MEMS reflectivity suggest that some error is introduced by small non-uniformities in the reflectivity.
Date: August 14, 2007
Creator: Evans, Julia; Thomas, Sandrine; Dillon, Daren; Gavel, Donald; Phillion, Donald & Macintosh, Bruce
System: The UNT Digital Library
Controlling Stimulated Brillouin Backscatter with Beam Smoothing in Weakly Damped Systems (open access)

Controlling Stimulated Brillouin Backscatter with Beam Smoothing in Weakly Damped Systems

None
Date: August 14, 2007
Creator: Divol, L
System: The UNT Digital Library
Design of the Beam Delivery System for the International Linear Collider (open access)

Design of the Beam Delivery System for the International Linear Collider

The beam delivery system for the linear collider focuses beams to nanometer sizes at its interaction point, collimates the beam halo to provide acceptable background in the detector and has a provision for state-of-the art beam instrumentation in order to reach the ILCs physics goals. This paper describes the design details and status of the baseline configuration considered for the reference design and also lists alternatives.
Date: August 14, 2007
Creator: Seryi, A.; Amann, J.; Arnold, R.; Asiri, F.; Bane, K.; Bellomo, P. et al.
System: The UNT Digital Library
Design of the Beam Delivery System for the International Linear Collider (open access)

Design of the Beam Delivery System for the International Linear Collider

None
Date: August 14, 2007
Creator: Seryi, A.; Amann, J.; Arnold, R.; Asiri, F.; Bane, K.; Bellomo, P. et al.
System: The UNT Digital Library
Design of the Beam Delivery System for the International Linear Collider (open access)

Design of the Beam Delivery System for the International Linear Collider

None
Date: August 14, 2007
Creator: Seryi, A.; Amann, J.; Arnold, R.; Asiri, F.; Bane, K.; Bellomo, P. et al.
System: The UNT Digital Library
Material Damage Test for ILC Collimators (open access)

Material Damage Test for ILC Collimators

Simulations were completed to determine the energy deposition of an ILC bunch using FLUKA, Geant4 and EGS4 to a set of different spoiler designs. These shower simulations were used as inputs to thermal and mechanical studies using ANSYS. This paper presents a proposal to optimize the material choice and mechanical design of ILC spoilers jaws using ATF and benchmark the energy deposition simulations and the ANSYS studies giving the researchers valuable data which will help achieve a definitive ILC spoiler design.
Date: August 14, 2007
Creator: Fernandez Hernando, J.L.; /Daresbury; Blair, G.A.; Boogert, S.T.; /Royal Holloway, U. of London; Ellwood, G.E. et al.
System: The UNT Digital Library
The National Ignition Facility and the Golden Age of High Energy Density Science (open access)

The National Ignition Facility and the Golden Age of High Energy Density Science

The National Ignition Facility (NIF) is a 192-beam Nd:glass laser facility being constructed at the Lawrence Livermore National Laboratory (LLNL) to conduct research in inertial confinement fusion (ICF) and high energy density (HED) science. When completed, NIF will produce 1.8 MJ, 500 TW of ultraviolet light, making it the world's largest and highest-energy laser system. The NIF is poised to become the world's preeminent facility for conducting ICF and fusion energy research and for studying matter at extreme densities and temperatures.
Date: August 14, 2007
Creator: Moses, Edward
System: The UNT Digital Library
Technical Challenges for the Head-on Collisions and Extraction at the ILC (open access)

Technical Challenges for the Head-on Collisions and Extraction at the ILC

An interaction region with head-on collisions is considered as an alternative to the baseline ILC configuration. Progress in the final focus optics design includes engineered large bore superconducting final doublet magnets and their 3D magnetic integration in the detector solenoids. Progress on the beam separation optics is based on technical designs of electrostatic separator and special extraction quadrupoles. The spent beam extraction is realized by a staged collimation scheme relying on realistic collimators.
Date: August 14, 2007
Creator: Napoly, O.; Delferriere, O.; Durante, M.; Payet, J.; Rippon, C.; Uriot, D. et al.
System: The UNT Digital Library
Ultra-Intense-laser produced high-Z backlighters for Compton Radiography (open access)

Ultra-Intense-laser produced high-Z backlighters for Compton Radiography

None
Date: August 14, 2007
Creator: Tommasini, R
System: The UNT Digital Library