BASIC ENERGY SCIENCES -- Serving the Present, Shaping the FutureBASIC ENERGY SCIENCES -- Serving the Present, Shaping the Future
Transmission Electron Aberration-free Microscope (TEAM) Project Update
Altaf H. CarimDivision of Materials Sciences and Engineering
Office of Basic Energy SciencesU.S. Department of Energy
Basic Energy Sciences Advisory Committee meetingJuly 23, 2002
Energetic electrons as a probe of matterEnergetic electrons as a probe of matter
• strong (Coulombic) interactions (with both electrons and nuclei)
• very short wavelengths (~ 2.5 pm at 200 kV)
• high source brightness (~ 1032 s-1 m-2 ster-1)
• readily focused (can form images; probes ≤ 0.1 nm for scanning)
• exceptional spatial resolution (can exceed 0.1 nm for imaging)
High-energy electron scattering: TEM, STEMHigh-energy electron scattering: TEM, STEM
h
ADFHC
STEMTEM
SCAN 2
SCAN 1
Controlled environment TEM at University of Illinois at Urbana-Champaign (courtesy FS-MRL, UIUC)
Ray diagrams illustrating reciprocity (courtesy J. Silcox)
Collaborative effort from four DOE-BES centersCollaborative effort from four DOE-BES centers
Advanced Light Source
Stanford Synchrotron
Radiation Lab
National Synchrotron Light Source
Advanced Photon Source
National Center for Electron
Microscopy
Shared Research Equipment Program
Center for Microanalysis of
Materials
Electron Microscopy Center for Materials Research
High-Flux Isotope Reactor
Intense Pulsed Neutron Source
Combustion Research Facility
James R. MacDonald Lab
Pulse Radiolysis Facility
Materials Preparation Center
Los Alamos Neutron Science
Center
Center for Nanophase
Materials Sciences
Spallation Neutron Source
Linac Coherent Light Source
Center for Integrated
Nanotechnologies
MolecularFoundry
Newest NSRCs at ANL and BNL
What is the TEAM project?What is the TEAM project?
• A collaborative development project to design, build, and operate next-generation electron microscopes
• Capitalize on several recent major developments, including the correction of limiting lens aberrations
• Definition of a common base instrument platform, with a modular approach to tailoring instruments for specific purposes
• Focus on enabling new, fundamental science via
• quantitative in-situ microscopy
• synchrotron spectral resolution at atomic spatial resolution
• sub-Ångstrom resolution in real time and 3-D
Modular experimental stations for in-situ workModular experimental stations for in-situ work
Experimental insert: Designed for each experiment removable w/o disturbing optics.Structural support for experiments
Shrouding and support:Designed to Allow Insertion of Experiment Station
Beam Path
Objective lens:- Large gap- Low Cc
Feed throughsProvide Electrical and Mechanical Connection
High takeoff angleLine of Sight to Sample for Deposition and Detectors
Module loading (4” Port)
- Easily inserted- Stage is integral to module (side entry or transfer)
Side View
Top View
Courtesy Robertson, Twesten, Petrov & Zuo
Modular sample holder configurationsModular sample holder configurations
Electron transparent window
Electron transparent window
Transportable specimen holder
Wide-bodiedstage
Front-end of stage
Volume available for experimental tools
MEMS specimen
Feed-through
Department of Energy National Microscopy User Facilities, FS-MRL, ANL, LBL, ORNL
Modular MEMS specimen holder
for in situ studies(Initial designs can be employed in current
generation microscopes.)
Spherical and Chromatic AberrationSpherical and Chromatic Aberration
spherical aberration chromatic aberration
E2 > E1
rmin ≈ 0.6 λ3/4 Cs1/4
rmin is resolution limit
rchr ≈ Cc (ΔE / E0) β
rchr is disk of confusion from chromatic aberration
Benefits of Aberration CorrectionBenefits of Aberration Correction
d Å
PCT
F
Cs-C
c-corrected
Cs-corrected
+ Monochromator
Lorenzlens
A lens design at 200 kV intended for magnetic imaging (Lorentz microscopy) maintaining a
large, field-free volume at the sample (courtesy B. Kabius)
Spherical aberration correction provides much higher current at a given probe size for
quantitative STEM (courtesy J. Spence)
contrast
More Benefits of Aberration CorrectionMore Benefits of Aberration Correction
0
200
400
600
800
1000
1200
-4 -2 0 2 4
0.8 Å1.2 Å2.0 Å
Inte
nsi
ty
distance (Å)
Improvement in spherical aberration provides much improved signal in smaller probe sizes
(courtesy J. Silcox)
10.05.0 3.0 2.0 1.5 1.2 1.0 0.8 0.70.00
0.20
0.40
0.60
0.80
d / Å
Reducing chromatic aberration enhances resolution and contrast for imaging with
electrons undergoing energy losses, allowing chemically-specific images at atomic
resolution (courtesy B. Kabius)
Example : Si-K edge, 1.8 keVE = 50 eV, HT : 200 kV, gap = 25 mm
Cc = 5mm
Cc = 0.1mm
Cc = 0.01mm
How are aberrations corrected?How are aberrations corrected?
2 cm
2 cm
magnetic sector
Q1 Q2 slit Q3 S1 Q4 S2 S3 Q5 S4 Q6 S5 S6
Quadrupole-sextupole set used to correct aberrations in Gatan imaging filter (enhanced energy-loss spectrometer) (courtesy O. Krivanek)
Hexapoles and transfer doublets correct spherical aberration in current Jülich instrument (courtesy M. Haider and H. Rose)
Schematic of proposed “ultracorrector”: quadrupole septuplets + many octupoles (courtesy M. Haider and H. Rose)
Impact of Aberration Correction on MicroscopyImpact of Aberration Correction on Microscopy
0.0001
0.001
0.01
0.1
1
1800 1840 1880 1920 1960 2000 2040
Res
olu
tio
n (
An
g.-1)
Year
Electron Microscope
Light Microscope
Corrected EM
Ross
Amici
Abbe
Ruska
Marton
Dietrich(200keV)
Haider(200keV)
Current
(Courtesy J. Silcox, after Harald Rose)
STEM (120 keV) {Batson et al.}
TEAM aims to enable new fundamental scienceTEAM aims to enable new fundamental science
Some examples:
• Nanoscale tomography, including 3-dimensional determination of glass structure and possibly location of individual point defects
• Direct observation of atomic level microstructure during controlled, quantifiable deformation
• In-situ control of electric and magnetic fields for direct observations of interfacial structure, segregation, and defects in active devices and changes induced by fields
• Single-column microanalysis, including chemical state information available by improved energy resolution
Recent breakthroughs and opportunitiesRecent breakthroughs and opportunities
(courtesy J. Spence)
Recent breakthroughs and opportunitiesRecent breakthroughs and opportunities
(courtesy J. Spence)
Recent breakthroughs and opportunitiesRecent breakthroughs and opportunities
(courtesy J. Spence)
Recent breakthroughs and opportunitiesRecent breakthroughs and opportunities
(courtesy F. Ross)
Recent breakthroughs and opportunitiesRecent breakthroughs and opportunities
(courtesy F. Ross)
Recent breakthroughs and opportunitiesRecent breakthroughs and opportunities
(courtesy F. Ross)
Status of TEAM projectStatus of TEAM project
• Preliminary “vision document” was supplied for BESAC subpanel’s 2000 report; the subpanel recommended favorable consideration of such an effort
• Second workshop last week at Berkeley drew attendance of over 100 and very strong interest in, and expressions of support for, the program
• Scientific advisory board established to provide guidance
• Full proposal involving at least the four electron beam microcharacterization centers, with possible participation from other parties, is expected by the end of the year.
• Rough estimates of cost are in the neighborhood of $70M over five years.