1 BROOKHAVEN SCIENCE ASSOCIATES A Wiggler Beamline for XAS at NSLS-II Paul Northrup NSLS-II Project and Environmental Sciences Department Brookhaven National Laboratory July 18, 2007 NSLS-II User Workshop

2 BROOKHAVEN SCIENCE ASSOCIATES Mission and Scope Diverse science applications: – Material science and catalysis – Environmental and geological sciences – Life sciences and biology – Chemistry and physics High productivity Advanced capabilities befitting an advanced source Part of larger picture, including – Soft bend and 3-pole wiggler sources – “Tender” energy range (1-5 keV) and Quick XAS – Beamlines moved from NSLS

3 BROOKHAVEN SCIENCE ASSOCIATES Draft Design Synthesis of: user input (so far), and what is technically possible Purpose of Workshop: Gather more user input and comments Refine design and needs Many design decisions are being made NOW Formation of “Beamline Advisory Team” begins here Subject to change for technical/facility reasons

4 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Sources for XAS Type:Useful range:Flux:Brightness: (vs NSLS Bend) Soft Bend:1-5 keV2x 100x bright, lower-energy 3-Pole Wiggler: 2-35 keV2x25x improvement on NSLS bend Damping Wiggler: 2-65 keV250x10 4 x very high power and brightness

5 BROOKHAVEN SCIENCE ASSOCIATES DW100 Source Characteristics Heat load: total radiated power = 64.6 KW maximum aperture 1 mrad horiz. x 0.15 mrad vertical (or 30 x 4.5 mm at monochromator) delivers 8KW will require cooling of nearly all samples Source-to-optics distance is ~30m, sample 40-50m Source size: ~100um horiz. x 6um vert. x 7m long 1 mrad off-axis, source appears 7mm wide Energy-dependent spatial distribution of beam

6 BROOKHAVEN SCIENCE ASSOCIATES Energy-dependent spatial distribution <5% variation within beam spot.

7 BROOKHAVEN SCIENCE ASSOCIATES Beamline Layout and Optics Be window with protective graphite filter Additional filters Collimating mirror collimation heat load harmonics rejection Pd-coated glidcop, cooled

8 BROOKHAVEN SCIENCE ASSOCIATES Beamline Layout and Optics Monochromator (LN2-cooled) Horizontal focusing Photon shutter All inside FOE Two experimental hutches

9 BROOKHAVEN SCIENCE ASSOCIATES Beamline Layout and Optics Horizontal focusing options: - Sagittal focusing of 2nd crystal of monochromator - Toroidal mirror

10 BROOKHAVEN SCIENCE ASSOCIATES Beamline Layout and Optics High energy resolution option: - Second monochromator - in series with first - no cooling needed - useful for Cr, Mn, As, etc. - requires mechanism for perfectly matching tune

11 BROOKHAVEN SCIENCE ASSOCIATES Canting Separate 7m wiggler into two 3m segments Canting angle is ~2 mrad Optics must be designed to allow second set of components, and leave room for second beam to pass by only a few cm away

12 BROOKHAVEN SCIENCE ASSOCIATES Beam Characteristics at Sample Energy range: keV Energy resolution: Standard, e.g. Si(111) or higher-resolution mode Beam size depends on focusing and on energy Stability is a priority: beam position within 5 microns at sample energy calibration/repeatability within intensity repeatability through optics

13 BROOKHAVEN SCIENCE ASSOCIATES Beam Characteristics at Sample Preliminary flux estimates (for guidance only) Energy range:Beam size:Flux (ph/s/0.1%BW): keV4.5x30mm 1x keV2.5x30mm8x keV1.2x30mm2x10 14 High-resolution mode would have 1/10 flux Microbeam mode would have 1/100 flux at 1 micron

14 BROOKHAVEN SCIENCE ASSOCIATES Experimental Stations Two hutches in series, initially served by single beam Future canting will provide independent beam to each hutch Access to downstream hutch for experimental setup while upstream hutch is in use, but not the inverse.

15 BROOKHAVEN SCIENCE ASSOCIATES Downstream (bulk) Hutch: 3 stations 1)Classic benchtop XAS station -transmission, fluorescence -cryostat/LN2 stages -fluid, catalysis, and electrochemical cells -capable of grazing incidence geometry -ideal for polarization- dependent measurements -option for high-energy- resolution detector -suitable for wide variety of applications

16 BROOKHAVEN SCIENCE ASSOCIATES Downstream (bulk) Hutch: 3 stations 1)Classic benchtop XAS station 2) Controlled-atmosphere and containment station -operates either open or as glove box for air-sensitive samples -contained/clean enclosure for radioactive, nano, or hazardous materials -multi-element detector -expected applications in environmental, nano and biological sciences

17 BROOKHAVEN SCIENCE ASSOCIATES Downstream (bulk) Hutch: 3 stations 1)Classic benchtop XAS station 2) Controlled-atmosphere and containment station 3) Open floor space for larger roll-in apparatus -data and control channels and utilities available -expected uses include magnets, large-volume high pressure cell, and catalysis instruments

18 BROOKHAVEN SCIENCE ASSOCIATES Upstream (microbeam) Hutch Standard K-B mirror set focusing beam to ~1 micron enclosure can operate as glove box multi-element detector can accommodate diamond- anvil cell for measurements at high pressure suitable for single-crystal EXAFS wide variety of applications in material science, geology, and environmental science

19 BROOKHAVEN SCIENCE ASSOCIATES Bigger picture… One of several XAS beamlines at NSLS-II Neighboring soft bend and 3-pole wiggler beamlines could be developed for complementary lower-energy and Quick XAS facilities Other microprobe and nanoprobe beamlines optimized for imaging