ARTICLES BY BELL SYSTEM AUTHORS 289 



The constants A and B for the various alloys investigated are given in the 

 following table: 



Equation (1) applies to solute atom concentrations as high as 5 X 10'^ 

 per cc. At higher concentrations the mobilities are lowered due to increased 

 impurity scattering so that the computed conduction is higher than the 

 measured. 



Microstructures of Silicon Ingots.^ W. G. Pfann^ and J. H. Scaff.^ 

 Melds Trans., V. 185 (//. Metals, V. 1) pp. 389-392, June, 1949. 



Increasing Space-Clmrge Waves.'\ J. R. Pierce.^ //. Applied Phys., \. 20, 

 pp. 1060-1066, Nov. 1949. 



Abstract — An earlier paper presented equations for increasing waves in 

 the presence of two streams of charged particles having different velocities, 

 and solved the equations assuming the velocity of one group of particles to 

 be zero or small. Numerical solutions giving the rate of increase and the 

 phase velocity of the increasing wave for a wide range of parameters, cover- 

 ing cases of ion oscillation and double-stream amplification, are presented 

 here. 



Traveling-Wave Oscilloscope. J. R. Pierce. ^ Electronics, \\ 22, pp. 97-99, 

 Nov., 1949. 



.A.BSTRACT — This paper describes a 1,000 volt oscilloscope tube with a 

 traveling-wave deflecting system. The tube is suitable for viewing periodic 

 signals with frequencies up to 500 mc. A signal of 0.037 volt into 75 ohms 

 deflects the spot one spot diameter. A few milliwatts input gives a good 

 pattern, so that the tube can be used without an amplifier. The pattern is 

 viewed through a sixty power microscope. 



P-type and X-type Silicon and the Formation of Photovoltaic Barrier in 

 Silicon Ingots.f J. H. Scaff,^ H. C. Theurerer^ and E. E. Schumacher.^ 

 Metals Trans., \. 185 (//. Metals, V. 1) pp. 383-388, Jan., 1949. 



Longitudinal Xoise in Audio Circuits. H. W. Augustadt^ and W. F. 

 Kaxxexberg.^ Audio Engg., Y. 34, pp. 22-24, 45, Jan., 1950. 



Transistors. J. A. Becker.^ Compilation of three papers presented at 

 A. I. E. E. meeting Swampscott, Mass., June 20-24, 1949. Elec. Engg., 

 V. 69, pp. 58 64, Jan., 1950. 



t A reprint of this article ma\' he obtained on retjuest to the ecUlor of the B. S.T.J. 

 1 B.T.L. 



