Post on 04-Jul-2020
Argonne National Laboratory is managed by The University of Chicago for the U.S. Department of Energy
Spectromicroscopy in the 1–4 keV region: new opportunities for environmental scienceDavid Paterson1
Jay Brandes2, Jürgen Thieme3, Jörg Prietzel4, Ellery Ingall5, Ian McNulty1
1 Advanced Photon Source, Argonne National Laboratory2 The University of Texas at Austin3 Institute for X-ray Physics, University of Göttingen4 Chair of Soil Science, Technische Universität München5 Earth and Atmospheric Sciences, Georgia Institute of Technology, USA
2
X-ray microscopy and environmental science
X-ray microanalysis has and will continue to have a major impact onKnowledge of fundamental environmental processes, particularly in the food chainEffects of heavy metal contaminants and their biological remediation
Outline1. Motivation
a) High spatial resolutionb) Energy range
2. Introduction to 2-ID-B intermediate energy beamline and scanning x-ray microscope at APS
3. Environmental applicationsa) Phosphorus and oxygen bonding in marine organismsb) Sulfur speciation in soil
4. Summary and outlooknano-XRF and nano-XANES
3
Motivation
Many important processes occur at or across cell wall boundaries
20 nm length scale
Phosphorus, sulfur and metals are important trace elements in most processes
XRFSpectromicroscopy
4
Introduction to 2-ID-B intermediate energy beamline
Beamline designed to maintain high coherent flux– 5.5 cm period undulator brightest in 1–4 keV range
Major instruments– Scanning x-ray microscope using Fresnel zone plates– Coherent scattering and coherent diffraction imaging station– Upgrade of monochromator => 20X flux at key edges of P, S, Cl and
soon Ar, K and CaScience programs– Traditionally materials research and coherence/phase studies– Recently venturing into environmental and biological studies,
particularly µXRF and spectromicroscopy or µXANES with sub-micron spatial resolution, <100 nm
5
Characteristics• 1 – 4 keV• δ = 60 nm• 108 –109 ph/sContrast modes• Transmission• Phase contrast• Fluorescence• Micro-XANES
OSA
scan stage
sample
zone plate
APD or segmented detector
fluorescence detector
2-ID-B intermediate energy beamline and “nanoprobe”: vital statistics
Monochromaticity ~1000 typical, > 3000 peakCoherent area 50 μm 50 μmCoherent flux 2 105 ph/μm2 /s/0.1% BWFocused flux 4 107 ph/s/0.1% BW 50 nm spot
2 108 ph/s/0.1% BW 60 nm spot1 109 ph/s/0.1% BW 80 nm spot
6
Transmission– 2D imaging– Tomography – Phase contrast
Fluorescence Na -> P, S, Cl– Environmental and biological, highest
spatial resolution, coordinated with hard x-ray investigations
– Multi-layer coated spherical grating monochromator
10 µm
P
Cl
Patterned molecular conductorBEDT
Scanning x-ray microscopy 1–4 keV – 60 nm resolution
7
Helium Sample VLMtube
Fluorescence Photo-detector diode
Zoneplate
OSA
Fluorescence detection and sample mounting scheme
8
Phosphorus speciation in the marine environment
Phosphorus is a vital nutrient sustaining primary productivity in the world’s oceans Presence or absence of oxygen has a marked effect upon phosphorus release from particulate phasesBulk NMR studies show marine organic phosphorus consists of – phosphates (C-O-P bonding)– phosphonates (C-P bonding)
Distribution of each phosphorus type is highly variable over short length scales, possibly <200 nm?Chemical state mapping to separate the variety of phasesNew model of marine phosphorus cycling that takes into account micro-scale heterogeneity and speciation
9
Phosphorus fluorescence mapping of marine particulates
Absorption mapping of marine organic phosphorus particulates
– Low concentrations <1% make absorption XANES unsuitable
– High density regions are not necessarily phosphorus rich
– Use fluorescence yield
Fluorescence mapping to find phosphorus rich regions of interest
Collect fluorescence XANES spectra with nanoprobe
10
Phosphorus speciation in bulk spectra
Ultrafiltered Dissolved marine Organic Matter –80 m depth
Phytic acid phosphate
2-AminoEthylPhosphonate
P XANES spectra with 80 nm probePhosphorus speciation in marine particulates
11
Sulfur: why is it so important in soils?
S is highly reactive, exists in several oxidation states
S moves freely among lithosphere, hydrosphere and atmosphere
S is indispensable nutrient for plants and microorganisms
Speciation of S intimately linked with chemical state of soil
Changes are caused by pedogenic and anthropogenic processes and result in changes of soil properties
12
Animalmanures
and biosolids
Mineralfertilizers
Runoff anderosion
Leaching
Adsorbed ormineral sulfur
Plant residues
Plantuptake
Sulfate(SO4 )
Atmosphericsulfur
Elementalsulfur
Organicsulfur Immobilization
Mineralization Bacterial reduction
Bacterial oxidationOxidati
on
SO2 gas, SO4 rain
Reduced sulfur
Input to soilComponent Loss from soil
VolatilizationAtmosphericdeposition
--
The Sulfur Cycle
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Study of sulfur species in soil
Importance of sulfur speciation in soil contrasts with the lack of microanalysis techniques available Wet chemistry and bulk techniques:total sulfur can only be distinguished into operationally defined fractions Not possible to assign a certain fraction to a specific sulfur species
Spectromicroscopy allows characterization ofassociations of soil colloids and soil micro habitatselemental co-localization, identify mineral and organic phasesstructure sulfur speciationphosphorus speciationdifferences within and between associations
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0.0
500
1000
1500
2000
2500
0.0
2.465 2.47 2.475 2.48 2.485 2.49 2.495
Y
X
Fluorescence / a.u.
2.465 2.470 2.475 2.480 2.485 2.490 2.495 Photon Energy / eV
E = 2472.6 eV O
rganic disulfide S
Absorption edge E = 2477.5 eV
E = 2473.7 eV Thiol / organic m
onosulfide S
E = 2475.7 eV Sulfoxide S
E = 2480.5 eV Sulfone S
E = 2482.0 eV Sulfate S
J. Prietzel, J. Thieme,U. Neuhäusler, J. Susini,I. Kögel-Knabner,EJSS 54(2003) 1-11
Chemical analysis:IntegratedReduced ⇔ Oxidized
A typical XANES spectrum of sulfur species in soil
15
Fe-poor groundwater
Fe-rich groundwater
Silicate bedrock
Peat bogs
Soil
AB
CD
Sampling sites in the forest of Fichtelgebirge, Germany
Forest profile
16
Reduction
DC
BA
Sampling sites
Groundwaterinfluence
Soil horizons
Reduction
Hydrological gradient at sampling sites
17
Bulk/average spectra
Depth
B Srw anox (122/123)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
C Gr anox (118/119)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
C H1 anox (93/94)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
C H2 anox (78/80)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
D H2 anox (91/92)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
D Aa anox (104/105)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
A Of anox (101/103) and (106/107)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
D H3 anoxic (76/77)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0A Oh anox (89/90)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0B H2 anox (82/81) and (83/81)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
B Aeh anoxic (110/111)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
B H1 oxic (139/140)
Energy / eV
2465 2470 2475 2480 2485 2490 2495
Fluo
resc
ence
inte
nsity
(a.u
.)
0.0
0.2
0.4
0.6
0.8
1.0
A Go Bv (61/62) and (63/64)
Energy / eV
2465 2470 2475 2480 2485 2490 2495
Fluo
resc
ence
inte
nsity
(a.u
.)
0.0
0.2
0.4
0.6
0.8
1.0
B Srd (65/66)
Energy / eV
2465 2470 2475 2480 2485 2490 2495
Fluo
resc
ence
inte
nsity
(a.u
.)
0.0
0.2
0.4
0.6
0.8
1.0
A Bv anox (39/40)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI/I
0
0.0
0.2
0.4
0.6
0.8
1.0
A Aeh anox (36/38) and (37/38)
Energy / eV
2465 2470 2475 2480 2485 2490 2495
Fluo
resc
ence
inte
nsity
(a.u
.)
0.0
0.2
0.4
0.6
0.8
1.0
D Gor anox (47/48)
Energy / eV
2465 2470 2475 2480 2485 2490 2495
Fluo
resc
ence
inte
nsity
(a.u
.)
0.0
0.2
0.4
0.6
0.8
1.0
C Aa anox (45/43)
Energy / eV
2465 2470 2475 2480 2485 2490 2495
Fluo
resc
ence
inte
nsity
(a.u
.)
0.0
0.2
0.4
0.6
0.8
1.0
A B C D
Reduction
Reduction
Sampling sites
18
C H1 anox (93/94)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
C H2 anox (78/80)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
A Of anox (101/103) and (106/107)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
A Oh anox (89/90)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0B H2 anox (82/81) and (83/81)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 00.0
0.2
0.4
0.6
0.8
1.0
B Aeh anoxic (110/111)
Energy / eV2465 2470 2475 2480 2485 2490 2495
Sulp
hur R
OI /
I 0
0.0
0.2
0.4
0.6
0.8
1.0
B H1 oxic (139/140)
Energy / eV
2465 2470 2475 2480 2485 2490 2495
Fluo
resc
ence
inte
nsity
(a.u
.)
0.0
0.2
0.4
0.6
0.8
1.0
A Aeh anox (36/38) and (37/38)
Energy / eV
2465 2470 2475 2480 2485 2490 2495
Fluo
resc
ence
inte
nsity
(a.u
.)
0.0
0.2
0.4
0.6
0.8
1.0
C Aa anox (45/43)
Energy / eV
2465 2470 2475 2480 2485 2490 2495
Fluo
resc
ence
inte
nsity
(a.u
.)
0.0
0.2
0.4
0.6
0.8
1.0
Reduction
Reduction
Analysis of catena
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1 2 3
4 550X50 µm2, 400X400 pixels0.5 sec dwell/pixel
1 – transmission2 – sulfur3 – aluminium4 – silicon5 – overlay
MAPS (S.Vogt)
Spatially resolved data, e.g. B H2 anoxic
20
Summary and future work for sulfur studies
Bulk sample studiesSuccessfully applied spectromicroscopy to soil samplesKeeping strictly anoxic conditions for the samples is criticalThe hydrological gradient is clearly reflected in the bulk spectra
OutlookBulk sample studies
Continue to study soils with extremely low concentrations of sulfurExtraction of single sulfur species from spectraComparison of bulk spectra from site to site
Spatially resolved data:Extraction of single sulfur species from spot to spotComparison from spot to spotComparison with bulk
Goal: Understand the fate of sulfur as a function of hydrological gradient
21
Conclusion and future directions
Motivation for high resolution µXRF and µXANES in environmental, biological and nano-materials studiesBeamline 2-ID-B intermediate energy scanning x-ray microscope
– Provides unique combination of high spatial resolution and energy resolution in the 1–4 keV energy range
– Combined with rapid sample changeover, in situ studies, hydrated samples and correlated hard x-ray analysis
Example studies– Phosphorus and oxygen in marine organisms and particulates– Sulfur cycle in soils
Future directionsInstrumentation
– Better detection schemes (increased solid angle)– Faster acquisition and better energy resolution– Better Fresnel zone plates to approach 10 nm resolution
Science?– Resolve sub-cellular structures and processes at and across the cell wall– Nano-XRF and nano-XANES
Opportunity to open new frontiers in environmental science
22
Acknowledgements
Jay Brandes & Ellery IngallUniversity of Texas at Austin & Georgia Institute of Technology
Jürgen Thieme & Jörg Prietzel, Nora TyufekchievaUniversität Göttingen & Lehrstuhl für Bodenkunde, TU München
Ian McNulty & Martin de JongeAdvanced Photon Source
Steve SuttonUniversity of Chicago
Ken Kemner & Shelly KellyArgonne National Laboratory
B. Twining, S. Baines, M. KissellSUNY Stony Brook
This work is supported by DFG under contract Pr 534/4-1 U. S. Department of Energy, Office of Science, Basic Energy Sciences, under contract W-31-109-ENG-38.
Thanks to ICXOM – Organizers.
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Techniques and instrumentation – future directions
Spatial resolution– Better zone plates
Fluorescence– Current 0.5 sec dwell– Desire 0.05 sec– Fly scan fluorescence mapping
Detectors– Solid angle and multi element– Faster acquisition rates - DSP 10 mm
24
Undulator Source
Spherical Mirror
Entrance Slit
Exit Slit
Spherical Grating
Zone Plate
31.120 12.150 3.500 8.0105.500 0.006
Beamline opticsHorizontal plane (m)
Minihutch Sample – Optics – Detector
2-ID-B@APS intermediate-energy beamline
25
Segmented detector – Integrating, voltage to multichannel ADC– 2 msec dwell, sub-msec achievable– Diatom @ 1790 eV, fly scan– 25 nm pixel, 1000 X 1000 pixels, 40 min
Benjamin Hornberger, Michael Feser, Chris JacobsenSUNY Stony Brook
10 µm10 µm
600 µm
Phase contrast imaging
26
C Aa anoxic sampling
Energy / eV
2460 2465 2470 2475 2480 2485 2490
Fluo
resc
ence
inte
nsity
/ a.
u.
0.0
0.2
0.4
0.6
0.8
1.0
C Aa oxic sampling
Energy / eV
2460 2465 2470 2475 2480 2485 2490
Fluo
resc
ence
inte
nsity
/ a.
u.
0.0
0.2
0.4
0.6
0.8
1.0
Time lag:
P. Kjeldsen 1993
Ddt
2
61⋅=
Material Diffusion Thickness Time lagcoefficient /µm /sec/cm2/s
Polyethylene 0.30.10-7 4 0.89Polypropylene 0.29.10-7 4 0.92Silicon 0.15.10-30 0.1 1.11.1020
Anoxic versus oxic sampling