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Cylindrical Collimating Mirror
EPU
Elliptical cylinderKB refocusing mirrors
Exit Slit
ExperimentalStation
Plane Mirror
EPU
Plane Grating
Beam Chopper
NSLS-II Soft X-ray Undulator Beamlines
Steve Hulberta
Dario Arenaa
Cecilia Sánchez-Hankea
Ruben Reiningerb
aBrookhaven National LaboratorybScientific Answers & Solutions, Madison, WI
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NSLS-II source brightness
1015
1016
1017
1018
1019
1020
1021
1022
Bri
gh
tnes
s [p
ho
ton
s/se
c/0.
1%b
w/m
m2 /m
rad
2 ]
10 eV 100 eV 1keV 10keV 100keV
Photon Energy
VUVhcrit
EPU100 VUV undulator100mm, L=4m, Kmax=14.0
EPU45 SXU45mm, L=4.0m, Kmax=4.33
U14 SCU14mm, L=2.0m, Kmax=2.2
W60 SCW,B=3.5T, 60mm,L=1.0m, K=19.6
DW100-1.8T,B=1.8T, 100mm,L=7m, K=16.8
U19 CPMU19mm, L=3.0m, Kmax=2.03
Ring parameters: 3.0 GeV, 0.5A, h=0.55nm, v=0.01nm, energy spread=0.001
Straight section parameters: 5m length: h=2.7m, v=0.945m; 8m length: h=18.2m, v=3.09m; h=v=h=v=h=v=0
Bend magnet parameters: h=0.65m, v=25.1m, h=0.032, v=-0.044, h=0.04m, h=0.056, v=v=0
25m-radius bend,B=0.4T, Ec=2.39keV
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1019
2
4
6
810
20
2
4
6
810
21
2
Bri
gh
tnes
s [p
ho
ton
s/se
c/0.
1%b
w/m
m2 /m
rad
2 ]
102
2 3 4 5 6 7 8 9
103
2 3 4 5 6 7 8 9
104
Photon Energy
Soft X-ray Elliptically-polarized Undulator
VUVhcrit
EPU42, linear modeperiod=42mm, L=4.0m, Kmax=4.3
Ring parameters: 3.0 GeV, 0.5A, h=0.55nm, v=0.01nm, energy spread=0.001
Straight section parameters: 5m length: h=2.7m, v=0.945m; 8m length: h=18.2m, v=3.09m; h=v=h=v=h=v=0
Bend magnet parameters: h=0.65m, v=25.1m, h=0.032, v=-0.044, h=0.04m, h=0.056, v=v=0
EPU45, min. linear modeperiod=45mm, L=4.0m, Kmax=4.3
EPU42, circular modeperiod=42mm, L=4.0m, Kx,max=Ky,max=2.9
EPU45, circular modeperiod=45mm, L=4.0m, Kx,max=Ky,max=2.7
Higher harmonic interference: use QEPU
Source polarization: linear (horiz., vert. or any angle in between), circular, or elliptical
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Proposed NSLS-II soft x-ray undulator beamlines
High resolutionSoft x-ray resonant magnetic and inelastic scattering (XRMS, RIXS)
High fluxSoft x-ray imaging and coherent scattering
XRMS
RIXS
Imaging
Coherent
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.
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High resolution soft x-ray undulator beamline : XRS, XRMS
XRS, XRMS (x-ray resonant [magnetic] scattering) endstationScientific themes / drivers:
1. Ordering Phenomena in Correlated Electron Materials2. Magnetic multilayers, superlattices & spintronic materials / devices3. Nanomagnetism: patterned & self-assembled4. “Soft” materials (e.g. complex polymers; C, N, O K-edges)
Beamline requirements- small spot size
>4 m spot overfills ~100 m 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
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High resolution soft x-ray undulator beamline : RIXS
RIXS (resonant inelastic x-ray scattering) endstationScientific 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: SAXES6. ELETTRA: ComIXS, BACH beam line
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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)
Eisebit & Luening, Nature 432, 885-888 (2004)
Beamline requirements (with 2013-state-of-the-art optics)
- flux > 1013 photons/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)
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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.
Magnification
Acceleration, focusing and magnification
Energy and angle selection
Beamline requirements (with 2013-state-of-the-art optics)- resolving power ~104
- STXM: flux > 1012 photons/s on sample, beam size 10m x 10m on Fresnel zone plate (full transverse coherence), <10nm x <10nm on sample
- PEEM: flux > few x 1013 photons/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, …
PEEM
http://xraysweb.lbl.gov/peem2/PEEM2-02.html
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Plane M3
PlaneGratingVLS
ExitSlit
CylindricalM2
Sample
Plane Ellipticals M4, M5
Soft x-ray beamline design:VLS PGM illuminated by collimated light
Side View
Horizontal Focusing by M4 -- 52:1
Rapid Switching: change M2 and M4
μrad (39) 28 μrad, (42) 32
μm (25) 35 μm, (47) 54
m) (2 4mL
200eV,h @ sizes source Effective
y'x'
yx
Possible planarM1
Beamline High resolution
High flux
Source to M1 27m 30m
M1 to M2 1m 1m
M2 to M3 PGM design PGM design
M2 to grating ~2m ~2m
Grating to exit slit 20m 10m
Exit slit to M4 1.85m 1.85m
M4 to M5 0.5m 0.5m
M5 to sample 1.0m 1.0m
Total 53.35m 46.35m
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Sample spot size
100nrad RMS planes0.5rad RMS Elliptical, cylinder meridional
-6
-4
-2
0
2
4
6
y (1
0-3m
m)
-4 0 4
x (10-3
mm)
root:'200 eV 1800 5': Sample Both
Good:6541 x: 0.0022797 Avg:1.9683e-05 y: 0.0011478 Avg:8.1257e-06
h=200eV: h=2.3m, v=1.1mh=1000eV: h=2.1m, v=1.1m
-3
-2
-1
0
1
2
3
y (1
0-3ra
d)
-3 -2 -1 0 1 2 3
x (10-3
rad)
root:'200 eV 1800 5': Sample Both Div
Good:6541 x: 0.001092 Avg:3.6449e-05 y: 0.00043957 Avg:4.4434e-06
h=200eV: h’=1.1mrad, v’=0.44mradh=1000eV: h’=0.8mrad, v’=0.3mrad
Req’d figure error
and divergence
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Calculated flux & resolving powerHigher resolution beamline1010’s @ 105 rp; 1012’s @ 104 rp
Higher flux beamline1012’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
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3D schematic of soft x-ray undulator layout
Cylindrical Collimating Mirror
EPU
Elliptical cylinderKB refocusing mirrors
Exit Slit
ExperimentalStation
Plane Mirror
EPU
Plane Grating
Beam Chopper
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M2
RCP LCP
M1
M3 M5
Side viewSingle beam mode
M5Top viewSingle beam mode
M1
M3
Top viewFast switching mode
M1
M3
Planar gratings
M4
RCP LCP
Planar gratings
M4
M2
Planar gratings RCP
LCP
RCP LCP
M2
M5M4
MechanicalChopper
Canted undulator optical schematic, polarization switching
Exit slit
Exit slit
Exit slit
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h=200eV: h=2.2m, v=1.1mh=1000eV: h=2.4m, v=1.1m
h=200eV: h=2.6m, v=1.1mh=1000eV: h=2.0m, v=1.1m
Spot sizes on sample, dual (canted) undulator beams
Near, e.g. LCP, beam Far, e.g. RCP, beam
To ensure complete overlap, defocus and/ortrim with baffles
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Comparisons of selected soft x-ray beamlines in the US
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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, …).