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BELL SYSTEM TECHNICAL JOURNAL 



accord with the measurements on the double crystal spectrometer made by 

 Bozorth and Haworth who show that after 20 hours' etching with 48% hy- 

 drofluoric acid at 30° C. the rocking-curve width of a plate originally lapped 

 with 100-mesh carborundum was still measurably greater than that of a 

 plate originally lapped with 600-mesh carborundum.^^ 



The measurements that have given half a micron for the depth of the dis- 

 turbed layer have been made with techniques incapable of showing part of 

 the disturbed material. The reflection-intensity measurements made with 



INSTRUMENT 



IONIZATION 

 CHAMBER- 



SINGLE ;^L 

 SPECTROMETER 



TECHNIQUE 



REFLECTION- 

 INTENSITY 

 MEASUREMENT 



INFORMATION OBTAINED 



COARSER ABRASIVE 

 GIVES HIGHER 

 INTENSITY. 



AMOUNT OF 

 LAPPING 



ETCHING TIME 



FILM 



SINGLE XL 

 SPECTROMETER 



PHOTOGRAPHY 



OF MISORIENTED 



MATERIAL 



FILM 



MATERIAL MISORIENTED 

 UP TO 3° -6°, DEPENDING 

 ON ABRASIVE 



IONIZATION 

 CHAMBER X 



ROCKING-CURVE 



MEASUREMENTS 



DOUBLE XL 

 SPECTROMETER 



ROCKING 

 ANGLE 



COARSER ABRASIVE GIVES LOVi/ER 

 AND BROADER ROCKING CURVE 

 WITH GREATER TOTAL INTENSITY. 

 MAXIMUM QUARTZ MISORIENTATION 

 MEASURED: ABOUT 1 MINUTE. 



PHOTOGRAPHY 



OF 

 THICK PLATES 



LAUE CAMERA 



MOST REFLECTION 

 FROM LAPPED SURFACES. 

 COARSER ABRASIVE 

 GIVES DARKER SPOT. 



Fig. 12. — Diagrammatic summary of instruments, techniques, and results 



the single cr>'Stal spectrometer can only show the material present in large 

 enough amount to cause measurable ionization in the ionization chamber. 

 The Davisson photographs with the single crystal spectrometer cannot show 

 material misaligned by less than 15 minutes. Any photographic technique 

 which is capable of measuring material misoriented by a few seconds has 

 shown a disturbed layer much thicker than half a micron at any worked 

 surface of quartz crystal. 



Figure 12 is a diagrammatic summar}^ of the various techniques that have 

 been described. Table 1 summarizes the present knowledge concerning the 



