Improvements in apparatus for determining potassium content in spaces containing potassium

摘要

PICT:0351266/III/1 PICT:0351266/III/2 PICT:0351266/III/3 PICT:0351266/III/4 The current impulses produced in the apparatus of the parent Specification by the Gamma-rays of potassium are indicated and summed by a rotating impulse relay or a direct current electric meter. The impulses from the ionization tube 1, Fig. 2, are preferably first amplified in known manner by a thermionic valve circuit 6 before passing to a rotating relay 8 of the type known in automatic telephony as a pre-selector. This operates a counting-train 10. When using a direct current motor meter 11, Fig. 3, a second valve circuit 7 is provided in which a negative potential is applied to the grid such that no current flows through the anode circuit and meter under normal conditions. An electrolytic meter may be used in place of the motor meter. In another modification, Figs. 5 and 6, the amplified current impulses rotate a ratchet-controlled pointer 14 over a scale; at regular time intervals a chopper bar 16 is depressed and causes the pointer 14 to make a visible record on a moving chart 15. The pointer is returned to zero by a spring after making each record.