1 BROOKHAVEN SCIENCE ASSOCIATES National Synchrotron Light Source II Damping Wiggler Beamline: XAS Preliminary Design Summary Paul Northrup January 16th, 2008

2 BROOKHAVEN SCIENCE ASSOCIATES Overall Mission To provide a versatile and highly productive facility for hard X-ray Absorption Spectroscopy for a wide range of scientific disciplines: Catalysis and energy science Environmental science and low-temperature geochemistry Life science and biology Nanomaterials and condensed matter research Earth and high pressure science To pursue and apply cutting-edge XAS capabilities and techniques appropriate to the advanced quality of the NSLS-II source

3 BROOKHAVEN SCIENCE ASSOCIATES Preliminary Design Careful consideration of: Community input User and scientific needs and new opportunities Technical feasibility Overall mission of NSLS-II Through: Workshops -- local and national Beamlines’ staff and representatives of scientific communities NSLS UEC White papers Technical, EFAC, and DOE reviews

4 BROOKHAVEN SCIENCE ASSOCIATES Beamline Requirements, Specifications Source requirements: Broad spectrum, high flux, non-coherent source Source stability (running in top-off mode): –position within 10% of source size, –vertical angle within 1  rad (for monochromatic energy stability) Specifications: Energy range: ~ keV, provisions to use up to 90 keV Tunable spot size from 0.2 x 0.2 mm to 5 x 55 mm Microbeam (1 x 1 micron) available Standard (10 -4 ) and high (10 -5 ) energy resolution modes available Controlled sample environment (air-sensitive or hazardous samples) Beamline stability scan-to-scan: position on sample within 5 microns, energy calibration within 0.05 eV

5 BROOKHAVEN SCIENCE ASSOCIATES Beamline Design -- Overview Top view: Side view: First Optic Enclosure (FOE) containing beamline optics and white-beam components Bulk XAS (with three sample positions) Shield wall 2 Experimental Hutches in line Microbeam XAS Beam 12

6 BROOKHAVEN SCIENCE ASSOCIATES Insertion Device Damping Wiggler, length 3.5 meters, in high-beta straight section Future upgrade: two canted 3.5m wigglers independently serving microbeam and bulk endstations

7 BROOKHAVEN SCIENCE ASSOCIATES Damping Wiggler Characteristics Flux: Brightness: Highest hard X-ray flux at Highest brightness of broad- NSLS-IIspectrum sources

8 BROOKHAVEN SCIENCE ASSOCIATES Damping Wiggler Heat Load (3.5m) Wiggler output 32 kW, 4 kW reaches beamline at max acceptance of 0.15 mrad (v) x 1.0 mrad (h) defined by optics Challenging to maintain broad energy range, stability “Divide and conquer” approach (absorbs:) front end mask 25 kW white-beam apertures3-7 kW (pass up to 4 kW) filters and attenuators1-2.5 kW white-beam mirror0-2.5 kW monochromator first crystal W monochromator second crystal(scatter) Preliminary thermal analyses show that this can be done Heat load on sample may be significant (>20 mW)

9 BROOKHAVEN SCIENCE ASSOCIATES White Beam Components Retractable attenuators, sequentially added for higher energy experiments (water-cooled, carbon) White-beam mirror 1.5 meter, Si (or GlidCop) substrate, water-cooled Two “stripes” (bare Si and Pt-coated) available Three positions: 2.0 or 3.15 mrad, or removed from beam –Thus 5 configurations to cover required energy range Vertical collimation and harmonic rejection Beam

10 BROOKHAVEN SCIENCE ASSOCIATES White Beam Components High Heatload Monochromator: LN2 cooled first and second crystals Side-by-side sets: Si(111) and Si(311) [or Si(333) instead] Beam

11 BROOKHAVEN SCIENCE ASSOCIATES Beamline Optics High energy resolution (10 -5 or better) monochromator In series with high-heatload monochromator Passes beam when not in use No LN2 cooling required, high precision mechanism Several crystal types being considered (less restrictions on material) Synchronization with primary monochromator is required Beam

12 BROOKHAVEN SCIENCE ASSOCIATES Beam Conditioning Optics Focusing mirror (~2:1) Two toroidal “stripes” match Mirror 1 Reflects in opposite sense to Mirror 1 Initial ray tracing calculations: spot size 0.2 x 0.2 mm at sample Beam

13 BROOKHAVEN SCIENCE ASSOCIATES Endstation 2: Bulk XAS Acceptance up to 0.15 x 1.0 mrad Spot size ~0.2x0.2 mm up to 5x55 mm Continuous-scan or step-scan modes of data collection Time-resolved (minutes) studies 3 sample positions

14 BROOKHAVEN SCIENCE ASSOCIATES Endstation 2: Bulk XAS Sample position 1: Classic benchtop XAS Transmission, fluorescence and grazing-incidence geometries In-situ measurements: electrochemical cells, gas and solution flow-through cells Heater, cryostat and LN2 cooling Standard and high-resolution (energy selective) detectors Detector for powder XRD pattern

15 BROOKHAVEN SCIENCE ASSOCIATES Endstation 2: Bulk XAS 2: Controlled environment XAS Multi-use enclosure: Glove box: controlled atmosphere Containment/fume hood for hazardous samples Multi-element detector Low-concentration samples Hazardous, nano, or radioactive materials

16 BROOKHAVEN SCIENCE ASSOCIATES Endstation 2: Bulk XAS 3: Space for move-in apparatus Large-volume high-pressure or catalytic cells High-field magnet Available control and data channels, utilities, etc. ~2 x 3 m

17 BROOKHAVEN SCIENCE ASSOCIATES Endstation 1: Microbeam XAS Conventional K-B mirror optics Focused spot ~1 micron Microbeam and single-crystal XAS Diamond anvil cell high-P XAS Multi-use enclosure Multi-element detector XRD detector shared with Endstation 2

18 BROOKHAVEN SCIENCE ASSOCIATES Estimated flux (delivered to sample at monochromator bandpass) 5.5 keV

19 BROOKHAVEN SCIENCE ASSOCIATES Estimated Flux: High Energy Resolution

20 BROOKHAVEN SCIENCE ASSOCIATES Summary: Initial Project Scope Two endstations included, one control station Single source and one set of optics serving both endstations Endstation 2 hutch can be accessed for set-up while Endstation 1 is in use; but not vice versa Accommodations (space, component design) made for future canting of source Heatload R&D 12

21 BROOKHAVEN SCIENCE ASSOCIATES Potential Upgrade/Build-out Path Add second canted wiggler source and beamline optics to provide independent beam for each endstation Addition of mirror in front end to divert low-energy portion of overlapped fans into a third station for high-flux bulk 2- 6 keV applications Complementary bulk/micro XAS beamline at adjacent dipole for 1-5 keV applications Net potential: core cluster of XAS endstations covering 1-90 keV energy range, bulk and microbeam capability 12 3

22 BROOKHAVEN SCIENCE ASSOCIATES Lower Energy (2-6 keV) Side Station