Sec. 10.25] 



GEIGER-MULLER COUNTERS 



335 



many as 100 or more uniformly spaced pulses per second, considerable error 

 is introduced in attempting to register random counts at this rate. If the 

 pulse width or the register resolving time is of the order of 0.01 sec, two or 

 more pulses occurring within an interval equal to or less than this are counted 



OUTPUT 



o 



-o 



V) 

 Ul 



£0 



ft 



-!(- 



tt 



tt 



OUTPUT 



Fig. 90. Diode coincidence circuit. [B. Howland, C. A. Schroeder, and V. P. Skipman, 

 Rev. Sci. Instruments, 18, 551 (1947).] 



as one and therefore result in considerable loss of counts at high rates. 



Typical recording circuits are shown in Figs. 86, 87, and 88. 



10.25. Coincidence Circuits. Coincidence circuits are electronic dis- 

 criminating devices that permit a count to be registered only when a pre- 

 determined number of counter tubes in the circuit discharge simultaneously, 

 or more exactly, within a short time interval, usually of the order of the 



