X-RAY MICROSCOPY 



Fig. 6. Photograph of the microfluoroscope. The variable microfocus x-ray source is shown at the 

 top center. The viewing microscope is in position for mounting a specimen or changing target. For view- 

 ing or exposure the microscope is moved on the short optical bench until its objective axis is coincident 

 with the axis of the microfocus tube. 



in Fig. 5 (16). The electron gun and lens 

 can produce a 10-100 micron beam at the 

 aUnnininn foil target with a specific loading 

 of up to lO'* watts 'mm-. The target also 

 serves as the vacuiun window. The specimen 

 and fluorescent screen are mounted on the 

 mechanical stage of an inverted metallurgi- 

 cal microscope. Target to screen distance 

 may be adjusted from 1 cm down to 50 

 microns. A photograph of the instrimient is 

 shown in Fig. 6. The viewing microscope is 

 moimted on a short optical bench so that it 

 can be displaced, as shown, to allow chang- 

 ing targets and specimens. This arrange- 

 ment has proven valuable for ordinary 

 microradiography as well as for the ex- 

 periments with x-ray sensitive materials 

 which may be enlarged in the electron 

 microscope (33). 



REFERENCES 



1. Heycock, C. T., and Neville, F. H., Trans. 



Chem. Soc. London, 73, 714 (1898). 



2. Goby, P., Comptes Rend., 156, 686 (1913). 



3. Dauvillier, a., Comptes Rend., 185, 1460 



(1927). 



4. Clark, G. L., and Bicek, E. J., in "Medical 



Physics," 2nd ed., p. 902, Glasser, O., ed., 

 Year Book Publishers, Chicago, 1950. 



5. ExGSTROM, A., in ''Progress in Biophysics and 



Biophysical Chemistry," Butler, J. A. V., 

 and Randall, J. T., eds., Academic Press, 

 New York, and Butterworth-Springer, Ltd., 

 London, 1950, p. 164. 



6. See also "Bibliography on Microradiography 



and Soft X-ray Radiography^" prepared by 

 Eastman Kodak Company, X-ray Division 

 and Kodak Research Laboratories, Roches- 

 ter, New York. 



7. Engstrom, a., this volume. 



8. Sharpe, R. S., this volume. 



568 



