abstracts of technical articles 267 



McCarthy, R. H.» 



Organization for Production Engineering, Mech. Eng., 75, pp. 785- 

 788, im. Oct., 1953. 



McGuiGAX, J. H.^ 



Combined Reading and Writing on a Magnetic Drum, I.R.E., Proc, 



41, pp. 1438-1444, Oct., 1953 (Monograph 2152). 



This ])aper points out that the characteristics of magnetic recording make it 

 possible to combine reading and writing in the same cell as it passes just 

 once under the head. Amplifier requirements for this method of opei'ation 

 are discussed and a suital)le design i)resented. A single head is used for l)oth 

 reading and writing. The i)rocess can be repeated in every successive cell at 

 a cell rate of 60 kc. The techniques described, which are applicable to either 

 parallel or serial systems, extend the utility of magnetic drums by allowing 

 date processing as well as data storage. 



McKay, K, G., see J. B. Johnson. 



McK\Y, K. G.i AND K, B. McAfee! 



Electron Multiplication in Silicon and Germanium, Phys. Rev., 91, 

 pp. 1079-1084, Sept. 1, 1953 (Monograph 2162). 



Electron multipUcation in silicon and germanium has been studied in the 

 high fields of wide p-n junctions for voltages in the pre-breakdown region. 

 Multiplication factors as high as eighteen have been observed at room 

 tempei'ature. Carriers injected b}' light, alpha particles, or thermal-genera- 

 tion are multiplied in the same manner. The time required for the midti- 

 plication process is less than 2 X 10"* second. Approximatelj' equal multi- 

 plication factors are obtained for injected electrons and injected holes. The 

 multiplication increases rapidly as "breakdown voltage" is approached. The 

 data are well represented by ionization rates computed by conventional 

 avalanche theory. In very narrow junctions, no observable multiplication 

 occurs before Zener emission sets in, as previoush' reported. It is incidentally 

 determined that the efficienc}- of ionization by alpha particles bomliarding 

 silicon is 3.6 ± 0.3 electron volts per electron-hole pair produced. 



ISIcSkimin, H. J.i 



Measurement of Elastic Constants at Low Temperatures by Means 

 of Ultrasonic Waves Data for Silicon and Germanium Single 

 Crystals and for Fused Silica, J. Ai)p. Phys., 24, pp. 988-997, Aug., 

 1953 (:\Ionograph2171). 



1 Bell Telephone Laboratories. 

 'Western Electric Company. 



