Radiation condition sensing apparatus with background discrimination

Claim 1

CONTROL APPARATUS COMPRISING; CONDITION SENSING MEANS PROVIDING A CONTINUOUS SERIES OF SPACED SIGNAL PULSES EACH OF WHICH IS INDIVIDUALLY SEPARATED BY A SHORT TIME INTERVAL UPON THE CONDITION SENSING MEANS BEING SUBJECTED TO A CONDITION TO WHICH IT IS SENSITIVE; A CONTROLLABLE CURRENT CONDUCTING DEVICE HAVING A PAIR OF INPUT ELECTRODES AND A PAIR OF OUTPUT ELECTRODES, BIASING MEANS, MEANS CONNECTING SAID INPUT ELECTRODES TO SAID BIASING MEANS TO ESTABLISH A FIRST STABLE STATE OF OPERATION FOR SAID CURRENT CONDUCTING DEVICE, MEANS CONNECTING SAID INPUT ELECTRODES TO SAID CONDITION SENSING MEANS TO CAUSE SAID CURRENT CONDUCTING DEVICE TO ASSUME AN UNSTABLE STATE OF OPERATION UPON THE PRESENCE OF EACH INDIVIDUAL SIGNAL PULSE AT THE INPUT ELECTRODES THEREOF, A LOAD IMPEDANCE, CIRCUIT MEANS CONNECTING SAID LOAD IMPEDANCE TO SAID OUTPUT ELECTRODES; AND FURTHER MEANS HAVING A FIRST PORTION CONNECTED TO SAID OUTPUT ELECTRODES AND HAVING A SECOND PORTION CONNECTED TO SAID LOAD IMPEDANCE, SAID FURTHER MEANS BEING CONSTRUCTED AND ARRANGED TO COMPARE THE SIGNAL DEVELOPED ACROSS SAID OUTPUT ELECTRODES WITH THE SIGNAL DEVELOPED ACROSS SAID LOAD IMPEDANCE.