Charge-coupled device (CCD) cameras have found wide application in electron microscopy. They provide much faster availability of image and diffraction data than photographic film, and this improvement in turn around time has allowed a tremendous increased in the efficiency of specimen evaluation, microscope operation and automation, and data recording. For some types of work the data collected with a CCD is of higher quality than when recorded on film. However, the CCD performance is seriously compromised when the microscope is operated much above 100 kV, due to the decrease in efficiency of the scintillator, which decreases the signal level, and increased lateral scattering of the electrons within the scintillator, which decreases the resolution. Together these effects can produce a detective quantum efficiency (DQE) which is far below that of film, and indeed too low for work such as low-dose imaging of proteins. The use of intermediate Voltage Electron Microscopes (IVEMs) operating at 300-400 kV is increasing as the many advantages of the higher accelerating voltage become more widely recognized, so the CCD performance on these microscopes is becoming more of a limitation. We plan to overcome the poor performance of CCD cameras on IVEMs by decelerating the electrons before they reach the camera. We will mount the CCD so that it can be floated to 200 kV, so that when the microscope is operated at 300 kV we will obtain the advantages of the IVEM but the camera will perform as well a on a 100 kV microscope. Further improvements will be made to the scintillator to produce even better signal and resolution characteristics than currently available. These adaptations will produce substantial benefits in work ranging from high-resolution structural studies of membrane proteins and viruses to the three dimensional study of cell ultrastructure.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Program Projects (P01)
Project #
2P01GM051487-05
Application #
6271828
Study Section
Project Start
1998-07-01
Project End
1999-06-30
Budget Start
1997-10-01
Budget End
1998-09-30
Support Year
5
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Lawrence Berkeley National Laboratory
Department
Type
DUNS #
078576738
City
Berkeley
State
CA
Country
United States
Zip Code
94720
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