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Nanopositioning R&D Plan Yong Chu Yong Chu Experimental Facilities Division, NSLS-II Experimental Facilities Advisory Committee Meeting April 23-24, 2009 HXN Team HXN beamline Yong Chu: Group Leader (Joined Jan. 2009) Beamline Scientist: Getting near making decision to hire
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Nanopositioning R&D Plan Yong Chu Yong Chu Experimental Facilities Division, NSLS-II Experimental Facilities Advisory Committee Meeting April 23-24, 2009
HXN Team HXN 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)
Technical Challenges • Focusing optics - fabrication of large (>100 mm), 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 mrad or better - preservation of uniform wave front
Schematic of the Overall Design Strategy for 1nm In-hutch DT ~ 0.1oC Temperature stability in mini-closure: DT < 0.05oC overall, < 0.01oC relative (bewteen optic & sample) Hutch wall Low-profile low thermal expansion stages with active feedback: Dz~0.2nm 1nm focus Engineered structures to compensate for measured floor vibration Active damping /isolation table: Dz~2-4nm Satellite bldg. wall on separate footing Specially engineered granite support with no vibration amplification: Dz<20nm Granite block Satellite bldg. Thick concrete slab structural filtering: Dz < 20nm Conventional natural site vibration: Dz < 25nm
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 mrad tilt error Resolution test of the one-dimensional laser Doppler linear actuator closed-loop control system by Deming Shu (APS)
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 f-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.
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
HXN Time Line FY2013 FY2014 FY2010 FY2012 FY2011 FY2009 FY2015 Experiment at CNM/APS Wedged MLL available Prototype-I Testing Prototype-I at APS or other SRs Experiment at HXN Build up NSLS-II Nanopositioning Lab: Research Vibration Damping for the HXN table Prototype-II construction Prototype-II Design
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