Intermediate and High Voltage Microscopy Chapter 16

1. Intermediate and High Voltage Microscopy Chapter 16

3. 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!

4. A million volt (MeV) TEM must maintain an accelerating voltage that is stable to within 0.5 volts.

5. 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

6. Hitachi 3 MeV is the most powerful TEM ever made

7. Hitachi 3 MeV is the most powerful TEM ever made Operator

8. It requires its own separate building Operator

9. 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

10. 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

11. Advantages of High Voltage EM Increased Specimen Penetration: As accelerating voltage increases the ability of the beam to penetrate also increases.

12. 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

13. 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

14. 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

15. 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).

16. 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 14;36(4):649-59

17. U.S. Department of Energy facility located at the University of California, Berkeley

18. Korea Basic Science Institutehttp://www.kbsi.re.kr/ JEM ARM-1300S “Morning Star” Ultra-High Voltage TEM Facility Under construction (2002.3)

19. 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)

20. Remote control system : FasTEM

21. 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

22. Intermediate Voltage (200-400 kV) JEOL JEM-4000FX Hitachi H-9000NAR

23. 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