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Experimental Station. Beam Chopper. Plane Mirror. Exit Slit. Elliptical cylinder KB refocusing mirrors. Plane Grating. Cylindrical Collimating Mirror. EPU. EPU. NSLS-II Soft X-ray Undulator Beamlines. Steve Hulbert a Dario Arena a Cecilia S á nchez-Hanke a Ruben Reininger b
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Experimental Station Beam Chopper Plane Mirror Exit Slit Elliptical cylinder KB refocusing mirrors Plane Grating Cylindrical Collimating Mirror EPU EPU NSLS-II Soft X-ray Undulator Beamlines Steve Hulberta Dario Arenaa Cecilia Sánchez-Hankea Ruben Reiningerb aBrookhaven National Laboratory bScientific Answers & Solutions, Madison, WI
Higher harmonic interference:use QEPU Source polarization: linear (horiz., vert. or any angle in between), circular, or elliptical
Proposed NSLS-II soft x-ray undulator beamlines High flux Soft x-ray imaging and coherent scattering High resolution Soft x-ray resonant magnetic and inelastic scattering (XRMS, RIXS) Coherent XRMS Imaging RIXS Source: Two 2m-long EPUs (EPU42 or EPU45) located in a 5m NSLS-II straight section. Operating modes: (1) uncanted and phased as a single 4m-long EPU, or (2) canted, by ~0.25 mrad, for fast-switching polarization capability.
High resolution soft x-ray undulator beamline : XRS, XRMS • XRS, XRMS (x-ray resonant [magnetic] scattering) endstation • Scientific themes / drivers: • 1. Ordering Phenomena in Correlated Electron Materials • 2. Magnetic multilayers, superlattices & spintronic materials / devices • 3. Nanomagnetism: patterned & self-assembled • 4. “Soft” materials (e.g. complex polymers; C, N, O K-edges) • Beamline requirements • - small spot size • >4 mm spot overfills ~100 mm crystal at critical angle of ~4° (h=700eV) • - high energy resolution (select different multiplet states) • - high flux (detect weak, diffuse features in scattered beam) • Comparable endstations (incomplete list) • 1. NSLS X1B, X13A, U4B • 2. ALS BL 4.0.1 • 3. APS 4-ID-C • 4. ESRF ID-08 (N. Brookes), Rogalev BL, XMaS • 5. Diamond: Peter Hatton endstation, BLADE • 6. BESSY-II: Helmut Zabel endstation • 7. Pohang LS: J-H Park BL • 8. Swiss Light Source • 9. Spring-8
High resolution soft x-ray undulator beamline : RIXS • RIXS (resonant inelastic x-ray scattering) endstation • Scientific themes / drivers: • 1. Correlated Electron Materials • low energy excitations (excitions, orbitons, HTc “stripe” formation, etc.) • field- and temperature-driven phase transitions • bulk sensitivity • 2. Organic molecules (incl. fullerenes, nanotubes) • Beamline requirements • - Small spot size (collect large solid angle, possibly no entrance slit) • - Very good energy resolution (precise selection of initial state) • - Highest flux possible (very low inelastic cross section) • Comparable endstations (incomplete list) • 1. NSLS X1B (commercial Scienta analyzer) • 2. MAX-III (J. Nordgren program) • 3. ALS beamlines 7.0.1, 8.0.1, MERLIN (lower energy) • 4. ESRF: AXES instrument (U. of Milan) • 5. Swiss Light Source: SAXES • 6. ELETTRA: ComIXS, BACH beam line
High flux soft x-ray undulator beamline : Coherent Scattering • Techniques: scattering, diffraction, coherent SAXS, diffraction imaging, holography,… • Scientific themes / drivers: • image the mesoscopic non-crystalline world (few x 10nm resolution), e.g. large cells, magnetic domains, … • measure time-dependent fluctuations in materials (correlated spectroscopy) • 3D imaging of granular materials (with grains around 30 nm) • Beamline requirements (with 2013-state-of-the-art optics) • flux> 1013photons/s on sample • beam size ~few m on pinhole • resolving power ~104 • Comparable endstations (incomplete list) • ALS – Cryo-capable Diffraction and Topography (transmission and reflectivity) • ALS – Steve Kevan’s Flange-o-Saurus • SSRL – speckle; EPU • BESSY • ESRF - Goedkoop; Van der Laan • NSLS - CCD based (transmission) Eisebit & Luening, Nature 432, 885-888 (2004)
Magnification Energy and angle selection Acceleration, focusing and magnification High flux soft x-ray undulator beamline : Microscopy • Techniques: STXM, phase contrast scope, full field scope, PEEM, spectro-scopy, … • Scientific themes / drivers: • Imaging nano- and mesoscopic world, simultaneous spectroscopic measurements • Imaging of single nano-elements , nano-contacts, or nano-magnets, to understand isolated behavior (no collective phenomena) • Structural and electronic information, differences between boundaries/interfaces and bulk. • Beamline requirements (with 2013-state-of-the-art optics) • resolving power ~104 • STXM: flux> 1012photons/s on sample, beam size10m x10mon Fresnel zone plate (full transverse coherence), <10nm x<10nmon sample • PEEM:flux> few x 1013photons/s on sample, beam size~few m on sample • Comparable endstations (incomplete list) • NSLS/CFN, ALS, BESSY, ESRF, SLS, Trieste, Spring8, Pohang Light Source, Diamond, Soleil, HASYLAB, … http://xraysweb.lbl.gov/peem2/PEEM2-02.html PEEM
Soft x-ray beamline design:VLS PGM illuminated by collimated light Possible planarM1 • Rapid Switching: change M2 and M4 Side View • Horizontal Focusing by M4 -- 52:1
Sample spot size and divergence h=200eV: h=2.3m, v=1.1m h=1000eV: h=2.1m, v=1.1m h=200eV: h’=1.1mrad, v’=0.44mrad h=1000eV: h’=0.8mrad, v’=0.3mrad • 100nrad RMS planes • 0.5rad RMS Elliptical, cylinder meridional Req’d figure error
Calculated flux & resolving power Higher resolution beamline 1010’s @ 105 rp; 1012’s @ 104 rp Higher flux beamline 1012’s @ 2104 rp; 1013’s @ 5103 rp Each soft x-ray undulator beamline would be equipped with at least 3 gratings, interchangeable under computer control
3D schematic of soft x-ray undulator layout Experimental Station Beam Chopper Plane Mirror Exit Slit Elliptical cylinder KB refocusing mirrors Plane Grating Cylindrical Collimating Mirror EPU EPU
Canted undulator optical schematic, polarization switching Side view Single beam mode M5 Exit slit M2 M3 M4 M1 Planar gratings RCP LCP RCP LCP M5 Exit slit M3 M4 Top view Single beam mode M2 Planar gratings M1 Mechanical Chopper M5 Top view Fast switching mode M3 M4 Exit slit M2 RCP LCP Planar gratings M1 RCP LCP
Spot sizes on sample, dual (canted) undulator beams Near, e.g. LCP, beam Far, e.g. RCP, beam h=200eV: h=2.2m, v=1.1m h=1000eV: h=2.4m, v=1.1m h=200eV: h=2.6m, v=1.1m h=1000eV: h=2.0m, v=1.1m To ensure complete overlap, defocus and/or trim with baffles
NSLS-II soft x-ray undulator beamlines • High-resolution, high-flux, polarization-switchable, soft x-ray beamline design, well matched to the high-brightness NSLS-II accelerator design • Example soft x-ray scientific programs well matched to this beamline design: XRMS, RIXS, imaging, coherent scattering • Actual buildout of soft x-ray beamlines will be based on the NSLS-II scientific program, including input from all stakeholders (NSLS-II staff, EFAC, NSLS-II users, …).