A relay memory for a thyratron counter

The paper describes an automatic mechanism consisting of sixteen interconnected relays and capable of carrying out a complicated cycle of operations in correct sequence in less than half a second. The apparatus is used in conjunction with a valve amplifier and an automatic thyratron counter for the analysis of α-particle groups by means of a magnetic focusing method. The relay mechanism arranges for alternate comparative counts of α particles to be made under two different sets of experimental conditions, A and B. At the end of a 9-sec. counting period under condition A, a relay memory A records and remembers the thyratron-counter readings; a change-over of experimental conditions from A to B takes place, and another relay memory B restores the thyratron counter to the state at which it stopped at the end of the previous 9-sec. B count, from which point it continues to count under experimental condition B. In the meantime, memory A continues to remember its reading for 10 sec. until the next change-over, when conditions are restored to state A again, the cycle being repeated throughout the course of the experiment.