CHAPTER 9 



DESCRIPTION OF COMMERCIAL 

 ELECTRON MICROSCOPES 



ELECTRON microscopy reached a new stage, in 1941, 

 when the Radio Corporation of America put on the market 

 the first commercial electron microscope ^^ of the magnetic 

 type, after a year's experience in a number of selected research 

 institutes. An instrument for research institutes ^^ was also 

 developed, in 1939, by Siemens and Halske in Germany, and 

 commercialized at about the same time as the R.C.A. microscope. 

 By the end of 1943, the large experience accumulated with the 

 first model enabled the R.C.A. to complete a very much simplified 

 magnetic microscope, a desk model of somewhat lesser per- 

 formance. The first commercial electrostatic microscope, also a 

 desk model, was completed by the General Electric Company, 

 Schenectady, at the end of 1942. The first British magnetic 

 electron microscope was put on the market by the Metropolitan 

 Vickers Electrical Co., Ltd., in 1944. 



L R.C.A. Magnetic Miscroscope, Floor Model, Type B 



Figure 17 is a photograph of two magnetic microscopes of 

 the R.C.A., side by side. The floor model, "Type B," stands 

 almost 7 ft high. Large as it is, it is considerably smaller than 

 several of the experimental models which preceded it, and 

 occupies very little floor space. This has been achieved by pack- 

 ing all the electrical supplies, control gear, and exhaust system 

 into the comparatively small space of the pillar behind the 

 microscope proper. The only exceptions are the mechanical 

 pumps which are mounted separately to avoid vibration. 



In the design of this instrument, no simplifications were at- 



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