Radio age research, manufacturing, communications, broadcasting, television (1941)

degrees iiccordint; to the density and composition of its various parts. When the beam emerges from the far side, it bears the pattern or "image" of the specimen, which is then magnified by powerful magnetic lenses that act upon electron beams very much as glass lenses act upon light. The pattern finally is projected upon the viewing screen. The ordinary optical microscope, using light to form the image of the specimen, is limited in its range by the wave-length of visible light. Objects appreciably smaller than this wave-length fail to interrupt or reflect the light in any visible fashion. The electron beam, however, has a wave-length only one 100-thousandth as great as that of visible light, with the result that it is interrupted or reflected by far smaller particles. When RCA first intro- duced the electron microscope, the immediate effect was to multiply by fifty times the range of human vision into the world of infinitely small organisms and particles— and the new microscope has now doubled that range. First micrograph made with the new microscope shows minute section of muscle fiber magnified 100,000 times. nervous system, of the sense organs and the glands, can the study of pathologically transformed cells, such as the cancer cells, be expected to produce reliable results. There is hope that the analyses by electron microscopes wiU lead to discoveries which may cast light over the character of the cancerous process and thereby provide a clue to the understanding of the cancer disease." Differs From Earlier Models In appearance, the new microscope differs radically from earlier types. Two desk-type working surfaces, each backed by a sloping control panel, flank a slender 7'/2-foot vacuum column that forms the heart of the instrument. The desk and control panel units are joined to the column at a slight forward angle to place all con- trols within reach of the operator, seated on a chair in the center. Built in the column at desk level is a viewing cham- ber equipped with windows on three sides to permit several persons to see the enlarged specimens at the same time. Magnification up to 30,000 times is obtained on the direct viewing screen, while enlargement up to 200,000 or more times is achieved from photographs taken by automatic plate and roll film cameras housed in the column. The new microscope operates on the same principles as its less powerful predecessors. A concentrated beam of electrons, originating from an electron gun, is directed through the specimen to be observed. As the electrons pass through the specimen, they are affected in varying Improved Features Listed Dr. Robert G. Picard, Manager of Scientific Instru- ments Engineering, RCA Engineering Products Divi- sion, who designed the new instrument, told the U.N. audience that the basic objective of the new design was to make operation so simple that people without spe- cialized training can operate it successfully. The im- proved features that have contributed to this objective are: I. Push button control of practically all operations, including photography; 2. A 30 per cent increase in resolving power—the ability to distinguish separate particles clearly at the outer limits of magnification; 3. Provision of controls that allow the operator to correct astigmatism easily while watching the image—a process that has involved much time and manipulation in previous models; 4. A new power supply, producing either 50,000 or 100,000 volts, and giving the electrons higher energy to penetrate thick specimens; 5. Stability in the electron gun, described by Dr. Picard as "an achievement which turned out to be the most difficult single engineering development in the new instrument." When it is installed at the Karolinska Institute, the new instrument will be the eighth RCA electron micro- scope in use in Sweden. Others of the new type are being built on order. More than 500 of the earlier electron microscopes already are in use on scientific and industrial research projects in the United States and 29 foreign countries. RAD/O AGE 15