Intermediate and High Voltage Microscopy

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Intermediate and High Voltage Microscopy Chapter
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The greater the accelerating voltage the shorter
the l
Therefore, a 50,000 volt (50 kV) electron has a
wavelength of 0.0055nm and a 1MeV electron has a
wavelength of 0.00123nm!
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A million volt (MeV) TEM must maintain an
accelerating voltage that is stable to within 0.5
volts.
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A million volt (MeV) TEM must maintain an
accelerating voltage that is stable to within 0.5
volts. With this coupled with a field emission
source one can achieve resolutions that are in
the range of 0.5Å
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Hitachi 3 MeV is the most powerful TEM ever made
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Hitachi 3 MeV is the most powerful TEM ever made
Operator
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It requires its own separate building
Operator
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Advantages of High Voltage EM
Increased Resolution Although still a long way
from a theoretical resolution of 0.0006 nm. the
best actual resolution has been achieved with a 1
MeV field emission TEM.
Nanocrystalline structure of silicon
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Advantages of High Voltage EM
Increased Resolution Although still a long way
from a theoretical resolution of 0.0006 nm. the
best actual resolution has been achieved with a 1
MeV field emission TEM.
1 MeV 200 kV 100kV
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Advantages of High Voltage EM
Increased Specimen Penetration As accelerating
voltage increases the ability of the beam to
penetrate also increases.
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Advantages of High Voltage EM
Increased Depth of Information The great depth
of information allows an entire thick section to
be viewed at once.
Dendrite in 3 mm thick section
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Advantages of High Voltage EM
Increased Depth of Information It also allows
for stereo pairs to be created from thick
sections.
Mitotic cell stereo pair
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Advantages of High Voltage EM
Reduced Beam Damage The increased speed of the
electrons actually decreases the likelihood of an
inelastic collision.
The same section viewed with 1 MeV vs. 100 kV
will have less contrast due to fewer scattered
electrons
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The Boulder Laboratory for 3-Dimensional Electron
Microscopy of Cells is located at the University
of Colorado. It is a National Resource Center
supported by the National Center for Research
Resources (NCRR) at the National Institutes of
Health (NIH).
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National  Center  for  Microscopy  and   Imaging  
Research - University of California, San Diego 
Lenzi D, Crum J, Ellisman MH, Roberts WM.
Depolarization Redistributes Synaptic Membrane
and Creates a Gradient of Vesicles on the
Synaptic Body at a Ribbon Synapse. Neuron 2002
Nov 1436(4)649-59
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U.S. Department of Energy facility located at the
University of California, Berkeley
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Korea Basic Science Institute
http//www.kbsi.re.kr/
JEM ARM-1300S Morning Star Ultra-High Voltage
TEM Facility
Under construction (2002.3)
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Functions of Morning Star

• Atomic resolution better than 0.12nm
• High-angle tilting 60 degree
• (a new function for 3-D structure analysis of
  materials in atomic level)
• Attachment of a new energy filtering system
• (functions for contrast enhancement, chemical
  analysis and electron structure analysis)
• Availability of various specimen holders for in
  situ study
• (capable of temperature variations from liquid He
  to 1500oC, as well as strain variations)
• Remote control operation
• (providing user-friendly system through remote
  operation, automatic alignment, and so on)

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Remote control system FasTEM
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U.S. HVEMs that have either shut down or are
underutilized University of Wisconsin
Madison Wadsworth Center Albany, New York SUNY
Stony Brook, New York
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Intermediate Voltage (200-400 kV)
JEOL JEM-4000FX
Hitachi H-9000NAR
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ESI allows an independent way to eliminate
scattered electrons from thick sections and when
combined with an intermediate voltage scope often
negates the need for a HVEM
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