High voltage transmission electron microscope

Transmission electron microscopes (TEM) with their variants (scanning transmission microscopes, analytical microscopes, high-resolution microscopes, high-voltage microscopes) are now crucial tools in the study of materials crystal defects of all kinds, radiation damage, ofif-stoichiometric compounds, features of atomic order, polyphase microstructures, stages in phase transformations, orientation relationships between phases, recrystallisation, local textures, compositions of phases... there is no end to the features that are today studied by TEM. Newbury and Williams (2000) have surveyed the place of the electron microscope as the materials characterisation tool of the millennium . 

The calcined samples are investigated by transmission electron microscopy (TEM) in a Philips EM 420 instrument operated at 120 kV. The specimens are deposited on a copper grid coated with a carbon film. High-resolution transmission electron microscopy (HRTEM) has been carried out at the Laboratory of Inorganic Chemistry, ETH Zurich, Switzerland, with a Philips CM20-ST microscope (accelerating voltage 300 kV). 

A "direct" observation of individual atoms is achieved in atomic resolution transmission electron microscopes (AR-TEM), in the scanning tunneling microscope (STM), and in the atomic force microscope (AFM) (5, 4). While AR-TEM are large machines with very high voltage (6 x 105 to 106 volts) applied to an electron-transparent small object, STM and AFM are small devices with ultrasensitive tip positioning mechanics that is suited for flat or near-flat objects and will... 

The basic construction of a modern transmission electron microscope is shown schematically in Figure 2.2. It consists of an electron gun and an assembly of electromagnetic lenses, all within a column which is evacuated to about 10 Torr (= 2.7 x 10 Pa). The beam of electrons produced by the electron gun is accelerated by a high voltage and then focused onto... 

All measurements are performed using the refractive index of CdS. In the case of cadmium sulfide nanoparticles produced in the w/o microemulsion the viscosity rj and the refractive index no of the continuous oil phase, namely the xylene-pentanol (1 1) mixture ( = 1.454 cP, D = 1165) are used. Consequently rj and no for water are used when the CdS nanoparticles are redispersed in the aqueous phase. Morphology and size of the redispersed CdS particles are also determined by transmission electron microscopy. Therefore, a small amount of the aqueous solutions is dropped on copper grids, dried and examined in the EM 902 transmission electron microscope (Zeiss) (acceleration voltage 90 kV). The high amount of surfactant brings also difficulties for the preparation of the samples for TEM measurements and consequently samples have to be washed with water to reduce the amount of surfactant. 

Provides an up-to-date collection of micrographs from the millimeter scale down to the micrometer and nanometer scale from all types of microscopes (optical microscope, scanning, and transmission electron microscopes (SEM and TEM), environmental scanning electron microscope, high-voltage electron microscope, atomic force microscope)... 

Transmission electron microscopy (TEM). The identification of Ag-NPs and their size analysis were carried out using high-resolution transmission electron microscopy (TEM). A Phillips CM 12 (Amsterdam, Netherlands) microscope with an acceleration voltage of 120 kV was used. The samples were prepared by spraying silver sols onto carbon-coated copper grids and then analyzed. 

---