JEOL JEM-2100 HR TEM
•MEC 113 & MEC 113a
•CCD camera (Orius SC1000, Gatan)
•Point resolution 0.23 nm
•Line resolution 0.14 nm
•STEM resolution 1.0 nm
•EDS chemical analysis (Thermo Electron Corp.)
•In-column annular dark field detector
• EELS (model 776 Enfina 1000, Gatan)
•Tomography unit for reconstruction of 3D images
•Temperature control down to 77 K
•Magnetic imaging resolution 2.2 nm
MSE 421/521 Structural Characterization
Historical Development
1931 – Ruska & Knoll build first EM lenses
capable of 400x. Siemens obtains patent.
1933 - Ruska builds first TEM (HVI, TU Berlin)
1938 - First practical TEM constructed at
University of Toronto by Burton et al.
1939 - Siemens launches first commercial TEM
1947 - DA-1, JEOL’s first commercial TEM
1970s - STEM developed
1986 - Ruska shares Nobel Prize in Physics
1990s - EELS developed
2005 - FEI launches TITAN
2007 - Boise State takes delivery of
JEOL 2100HR TEM
MSE 421/521 Structural Characterization
Projection Limitation
T.L. Hayes, Biophysical Aspects of Scanning Electron Microscopy,
SEM 1 1-10 (1980).
MSE 421/521 Structural Characterization
The Family of TEMs
All TEMs have an electron gun; condenser, objective, and
projector lens systems; and a signal detection device
Hitachi
DSTEM
Add scan coils and it becomes
a scanning TEM (STEM)
JEOL 2100 HR TEM
Add EDS/EELS and it becomes
an analytical TEM/STEM
MSE 421/521 Structural Characterization
The Family of TEMs
At very high voltage - HVEM
1 MV
1.25 MV
World's largest
microscope
3 MV
Hitachi
DSTEM
JEOL-1000, High-Voltage
Electron Microscope Lab,
University of Colorado
JEM-ARM1300S "Morning
Star", Korea Basic Science
Institute
Center for Ultra-High Voltage
Electron Microscopy, Osaka
University
MSE 421/521 Structural Characterization
The Family of TEMs
Add Cs correction
ZEISS HRTEM with in-column
energy filter
FEI Titan
MSE 421/521 Structural Characterization
JEOL JEM-ARM200F
TEM
Source
First condenser lens, C1 (Spot Size)
First demagnified source image
Second condenser lens, C2 (Brightness)
Condenser aperture
Specimen
Objective lens
Back focal plane
Objective aperture
First image plane
Selected area aperture
Intermediate or diffraction lens
Second image plane
Projector Lens(es)
Screen
MSE 421/521 Structural Characterization
Image or SADP
Source
First condenser lens, C1 (Spot Size)
First demagnified source image
Second condenser lens, C2 (Brightness)
Condenser aperture
Specimen
Objective lens
Back focal plane
Objective aperture
First image plane
Selected area aperture
Intermediate or diffraction lens
Second image plane
Projector Lens(es)
Screen
image
MSE 421/521 Structural Characterization
diffraction
pattern
Rotary Pump
Pressure: 1 .0 – 0.1 Pa
Oil usually used as lubricant and gas seal (but oil-free is also possible)
High-P side: atmosphere
Low-P side: limited by vapour pressure of oil (≥ 0.1 Pa)
Used to pump specimen exchange airlock, chamber (from air), and back the DP, so it is typically
attached to roughing manifold
Reliable and cheap, but dirty and noisy
MSE 421/521 Structural Characterization
Diaphragm Pump
Rated in litres/min
Oil-free
High-P side: can be many atmospheres
Low-P side: typically rated in litres/minute
Used to back DP or turbopump
MSE 421/521 Structural Characterization
Diffusion Pump
Pressure: 10-1 - 10-8 Pa
High-P side: 10-1 Pa (requires forepump)
Forepump can be switched off when TEM is in use because of empty space between DP and manifold
At bottom of column, near back, used to pump viewing chamber and film compartment
Low-VP polyphenyl ether Santovac® 5 commonly used (synthetic, non-hydrocarbon)
Oil may crack/char (oxidise) in high-T or high-P
Reliable, simple, no noise/vibration, inexpensive (but slow – about 30 mins to warm up)
MSE 421/521 Structural Characterization
Turbo Pump
Pressure: 10-1 - 10-5 Pa
High-P side: ~10-1 Pa (usually backed, but in theory can operate – slowly - at atmosphere)
Like a jet engine, with rotating (rotors) and fixed (stators) blades
20,000 – 50,000 rpm
More likely to fail (spectacularly) than DP
Oil-free, but some vibration (not too bad)
Tight tolerances on machining, so expensive
MSE 421/521 Structural Characterization
Sputter Ion Pump
Pressure: 10-5 - 10-10 Pa
anodes
magnet
Ti (cathode)
High-P side: 10-4 Pa (needs serious backing)
Electrons accelerated (5 keV) from Ti cathode and ionise gas molecules, which go to cathode
Gas atoms either form inert compound (TiC) or are embedded in Ti (Ar) – released on shut-off
Sputtered Ti condenses on anode and acts as a getter material (chemisorption)
The smaller the ionic current, the lower the vacuum
No moving parts, no oil
MSE 421/521 Structural Characterization
Cryogenic Pump
Pressure: ≥ 10-4 Pa
Liquid nitrogen cools sieves with large surface areas so gas condenses on them
Contaminants from vacuum or beam-sample interaction condense on ACD – not sample or apertures
Gases are released on shut-off
MSE 421/521 Structural Characterization
Pirani Gauge
Marcello Pirani, 1906
70 Pa – 0.01 Pa
Pressure decreases → Temperature increases (less heat lost to gas)
Temperature increases → Resistance increases
Resistance increases → Current decreases
Requires two Pt wires, one sealed (reference) and one in vacuum chamber (gauge)
Needs calibration with reference tube
Gauge wire can alternatively be kept at constant T and current required measured
MSE 421/521 Structural Characterization
Penning Gauge
10-1 Pa – 10-8 Pa
by several kV
http://www.esrf.eu/exp_facilities/ID18/pages/exp/equipment/vacuum/vacuum.html#penning
Electrons thermionically emitted from filament ionise gas molecules
Cations are attracted to cathode (collector), electrons to anode (grid)
Current in collector is proportional to rate of ionisation, which is a function of pressure
Calibration is difficult and gas-species dependent
MSE 421/521 Structural Characterization