Beryllium windows

To arrive at some idea of the precision attainable in direct absorptiometry with gases, methyl chloride contained in a metal cell with beryllium windows was systematically expanded by connecting the cell to a vacuum chamber, output currents being read after each expansion. The results were satisfactory.14... 

The usual target is a beryllium window plated underneath with the... 

For in situ x-ray diffraction measurements, the basic construction of an electrochemical cell is a cell-type enclosure of an airtight stainless steel body. A beryllium window, which has a good x-ray transmission profile, is fixed on an opening in the cell. The cathode material can be deposited directly on the beryllium window, itself acting as a positive-electrode contact. A glass fiber separator soaked in liquid electrolyte is then positioned in contact with the cathode followed by a metal anode (3). A number of variations and improvements have been introduced to protect the beryllium window, which is subject to corrosion when the high-voltage cathode is in direct contact with it. 

The anode is water cooled and the whole anode assembly evacuated. The X-rays pass through beryllium windows, which are transparent to X-rays. (Reproduced with permission from Monaco, H. t., Viterbo, D., Scordari, R, Gilli, G., Zanotti, G. and Catti, M. In Fundamentals of Crystallography, Giacovazzo, C., ed. International Union of Crystallography Texts on Crystallography, Oxford Science Publications.)... 

The gas is another phase which is detectable by microphonic photoacoustic method. The focused beam (at Beam Line 15A (PF)) at wavelength of 1.56 A was used for this experiment. Photoacoustic cell for gas phase measurement is shown in Fig. 9. The optical path was 10cm (x6mm O with beryllium windows (18mm d>, 0.5mm... 

X-ray diffractometer with copper target, beryllium window, nickel filter, and data acquisition and processing system... 

Fig. 3. Cross section of the side view of a typical EXAFS in situ cell (A) main body made of stainless steel (B) beryllium windows (C) convection baffles (D) gas inlet (E) liquid inlet (F) gas and liquid outlet (G) cooling jackets (J) thermocouple [reproduced from Dalla Betta et al. (29), with the permission of the American Institute of Physics].

The list in Table 3 is not exhaustive other typical window materials include Mylar , boron nitride, Teflon , and aluminum. Each of these materials can be modified for additional chemical resistance. For example, Kapton film can be purchased coated with graphite or Teflon , and beryllium windows can be coated with DuraCoat . There is no one window material that is suitable for all applications. The optimum choice... 

These issues were partially addressed by a design reported by Clausen and Tops0e (1991). These researchers developed a small reactor cell, which allows simultaneous measurements of catalytic activity and XAFS spectra. They stated that real reaction conditions were established, with catalyst temperatures up to 773 K and pressures up to approximately 100 bar. Details of the design were not published, but the authors stated that the cell consisted of stainless steel walls with two beryllium windows for transmission of the X-ray beam. A key... 

The most common laboratory source of X rays is a sealed X-ray tube, that is, a glass (or cerantic) vessel with a metal base, in which under conditions of high vacuum a beam of electrons is created, accelerated by an electric potential of 30 to 60 kV and focused onto a target of one of the abovementioned metals, thereby producing X rays which leave the tube through a beryllium window. When electrons bombard the target, both... 

Figure 1 Mossbauer spectrometer with velocity calibrator Mossbauer drive and detector. The sample is placed between drive and detector. For measurements at cryogenic temperatures, the sample is moimted in a cryostat equipped with Mylar or beryllium windows. (Reproduced with permission Wissel Gmbh)...

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