scholarly journals Scanning Wet Specimens

2004 ◽  
Vol 12 (3) ◽  
pp. 3-7
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Biological Samples ◽  
Natural Fibers ◽  
Living Cells ◽  
Environmental Scanning ◽  
Aqueous Dispersions ◽  
Biological Studies ◽  
Materials Research ◽  
Scanning Electron

Would it be useful if you could examine a wet, perhaps even a living, specimen in the scanning electron microscope? Of course we think that this would be impossible, given the vacuum the specimen would be subjected to in the microscope. However, in the realm of materials research, the Environmental Scanning Electron Microscope (ESEM) is being developed. Apparently this instrument has not been fully appreciated and utilized by biologists.As reviewed by Athene Donald, a pioneer in developing the ESEM, this instrument has been commercially available for a decade. It is still evolving as a useful tool in looking at materials such as cement, natural fibers, and aqueous dispersions. Applications of the ESEM. to biological Studies are extremely limited. However, studies on biological samples, even living cells, are possible (although not without problems and limitations).

Universal ESEM

1993 ◽  
Vol 51 ◽  
pp. 786-787
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Vacuum ◽  
Natural Extension ◽  
Necessary Condition ◽  
Environmental Scanning ◽  
Detection Systems ◽  
Small Gain ◽  
Detection Medium ◽  
Scanning Electron

The environmental scanning electron microscope (ESEM) has evolved as the natural extension of the scanning electron microscope (SEM), both historically and technologically. ESEM allows the introduction of a gaseous environment in the specimen chamber, whereas SEM operates in vacuum. One of the detection systems in ESEM, namely, the gaseous detection device (GDD) is based on the presence of gas as a detection medium. This might be interpreted as a necessary condition for the ESEM to remain operational and, hence, one might have to change instruments for operation at low or high vacuum. Initially, we may maintain the presence of a conventional secondary electron (E-T) detector in a "stand-by" position to switch on when the vacuum becomes satisfactory for its operation. However, the "rough" or "low vacuum" range of pressure may still be considered as inaccessible by both the GDD and the E-T detector, because the former has presumably very small gain and the latter still breaks down.

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