10. Spacecraft Charging Induced by Electron Beam Emission

1990 ◽  
Vol 95 (A8) ◽  
pp. 12209 ◽  
Author(s):  
T. Neubert ◽  
P. M. Banks ◽  
B. E. Gilchrist ◽  
A. C. Fraser-Smith ◽  
P. R. Williamson ◽  
...  

1987 ◽  
Vol 30 (1) ◽  
pp. 209 ◽  
Author(s):  
H. Okuda ◽  
J. R. Kan

Author(s):  
Federico Lucco Castello ◽  
Gian Luca Delzanno ◽  
Joseph E. Borovsky ◽  
Omar Leon ◽  
Grant Miars ◽  
...  

Author(s):  
G. G. Shaw

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.


Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.


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