basic energy sciences -- serving the present, shaping the future

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.