Recent advance in high voltage electron microscope has entailed an expanded application of a continuous observation of non-static structures in specimens at elevated temperature or under stress. In order to attain this end, the need for a VTR system capable of recording structural changes is increasingly felt. Through several investigations, we eventually decided to adopt an Image Orthicon tube, as pick-up tube, considering its high recording speed, reliability and ease of operation.In this paper, a detectable speed of the specimen depending upon the specified resolution, electron beam flux and size of the specimen is experimentally discussed by adjusting the gain of the amplifier so as to obtain an optimal condition. The TV system consists of a high-gain Image Orthicon tube and a transformer circuit which has a band width of 8MHz and a frame speed of 1/30 sec, as shown in Fig. 1.
When observing extremely fracturable specimens, such as organic compounds, clays and biological specimens by means of electron microscopy, it is very difficult to photograph the image of an object due to the very small current density of the irradiating electron beam. It is, therefore, desirable to use a high efficency image intensifier. The intensifiers presently used utilize Vidicon or Plumbicon camera tubes which exhibit comparatively low efficency. As a result, it is necessary to insert a photo-electron multiplier between the photo receiving surface and the surface of the camera tube. By so doing, the signal on the receiving surface is transformed into an amplified output signal, which involves considerably large shot noise arising from the collision of the photo-electron onto the electrodes or the fluorescent film in front of the second stage fiber optics plates.
This paper reports on the development of a cryostat for neutron smallangle scattering experiments on alkali metals under uniaxial compression in a temperature range from 5 K to room temperature. The investigation was motivated by earlier observations of 'premartensitic' anomalies in metallic lithium and potassium which seem to suggest that nuclei of a low-temperature phase might be generated in the undercooled bcc structure either by cooling alone or by additional mechanical deformation. Cooling to 120 K in lithium and to 5 K in potassium, respectively, without applied load produced only very slight changes in the SANS patterns. However, after uniaxial compression of 3% at these temperatures anisotropic scattering patterns developed, suggesting the formation of small particles embedded in the bcc matrix whose orientation is related to the deformation direction.
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