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1 BROOKHAVEN SCIENCE ASSOCIATES
Nanopositioning R&D Plan
Yong ChuYong Chu
Experimental Facilities Division, NSLS-II Experimental Facilities Advisory Committee Meeting
April 23-24, 2009
2 BROOKHAVEN SCIENCE ASSOCIATES
HXN TeamHXN beamline
Yong Chu: Group Leader (Joined Jan. 2009)
Beamline Scientist: Getting near making decision to hire
Ken Evans-Lutterodt (MOU Staff, Kinoform development, lead initial HXN effort )
Nanopositioning R&D
Engineer: Interviewing
1 nm R&D
Hanfei Yan (MLL theory, optics testing)
Enju Lima (coherent phase retrieval, optics testing)
Ray Conley (MLL fabrication, metrology)
Nathalie Bouet (postdoc, MLL processing)
James Biancarosa (technician, MLL fabrication)
3 BROOKHAVEN SCIENCE ASSOCIATES
Technical Challenges
• Focusing optics- fabrication of large (>100 m), wedged MLLs- thinning MLLs for x-ray energies at 10 keV or lower- bonding two MLLs into a monolitic optic- wedged MLLs are extremely chromatic
• X-ray Microscope- sub-nanometer positioning /scanning- sub-nanometer stability - small working distance ( < 1 mm)- integrated XRF detector with maximum solid angle- implementation of in situ controls or sample environments
• End-Station- vibration, temperature, air-flow, acoustic management
• Beamline optics - large coherence length at focusing optics- angular stability of 1 rad or better- preservation of uniform wave front
4 BROOKHAVEN SCIENCE ASSOCIATES
Schematic of the Overall Design Strategy for 1nm
Satellite bldg. Thick concrete slab structural filtering: z < 20nm
Conventional natural site vibration: z < 25nm
Specially engineered granite support
with no vibration amplification: z<20nm
Active damping /isolation table: z~2-4nm
Low-profile low thermal expansion stages with active feedback: z~0.2nm
Temperature stability in mini-closure: T < 0.05oC overall, < 0.01oC relative (bewteen optic & sample)
Granite block
Satellite bldg. wall on separate footing
Engineered structures to compensate for measured floor vibration
Hutch wall
In-hutch T ~ 0.1oC
1nm focus
5 BROOKHAVEN SCIENCE ASSOCIATES
Considerations for Nanopositioning• Actuator - piezoelectric with moderate travel distance
• Guidance/Carrier - avoid bearings, sliders, screws, gear-reducer, etc
- flexure-based motion for higher stiffness.
• Sensors- feedback on the “combined” motion
Laser Doppler Linear Encoder- require low noise enabling high res.
• Control - high speed/bandwidth
- need capability for “fly scan”
• Environment- suppression of low frequency vibration- temp. stability to prevent drift
Deming Shu’s Prototype Linear Flexure 2 mm travel range + 4 rad tilt error
Resolution test of the one-dimensional laser Doppler linear actuator closed-loop control system by Deming Shu (APS)
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6 BROOKHAVEN SCIENCE ASSOCIATES
Nanopositioning R&D Plan In collaboration with the APS:
• Develop a long travel (~3mm), high-stiffness, flexure-based xyz linear stages with laser encoding resolution of sub-nanometer.
• Develop a long range (~10°), high-stiffness, flexure-based rotary stage. - use high mechanical repeatability to build a look-up table to correct run-out and wobble errors.
• Develop MLL positioner, meeting the HXN requirements (the experience from the CNM/APS MLL instrument will be very helpful).
• Construct a HXN prototype (in air or He) combining the above components by FY2011-Q4.
• Develop vibration damping solutions for the HXN support frame/table.
7 BROOKHAVEN SCIENCE ASSOCIATES
HXN microscope
• The microscope design will be guided by the experience with the HXN prototype.
• Require differential laser encoding between the sample and the MLL optics.
• In vacuum for thermal stability.
• Integration of XRF detector.
• Require 0.2~0.5 nm stability.
• Work with a vender for construction
8 BROOKHAVEN SCIENCE ASSOCIATES
FY2009 FY2010 FY2011 FY2012 FY2013 FY2014 FY2015HXN Time Line
Prototype-I
Experiment at CNM/APS
Wedged MLL available
Testing Prototype-I at APS or other SRs
Prototype-II Design
Experiment at HXN
Prototype-II construction
Build up NSLS-II Nanopositioning Lab:
Research Vibration Damping for the HXN table
9 BROOKHAVEN SCIENCE ASSOCIATES
Summary
• Nanopositioning R&D will be focused on developing high-stiffness, flexure-based xyz linear stages and a rotary stage with long travel (~3mm + ~10°) in collaboration with the APS
• HXN prototype is planned to be constructed by FY2011-Q4.• HXN prototype will enable:
- testing of MLLs- investigating methods to bond two MLLs- identifying specific engineering/technical challenges required for the HXN microscope