Means of cancellation of the effect of random deviations in radioactive emission upon an analog d.c. voltage

Claim 1

A system which generates a D.C. signal proportional to an amount of radioactive energy present at a radiation detector means, including, radiation source and detector means, said detector means arranged to sense the amount of radioactive energy impinging thereupon and to generate electrical pulses proportional thereto, means connected to the detection means to modify the electrical pulses such that each pulse is of equal magnitude and equal time duration, an A.C. to D.C. converter connected to the electrical pulse modifying means to convert the pulses to a D.C. signal having an A.C. component, an A.C. amplifier connected to the A.C. to D.C. converter which produces a D.C. voltage of a predetermined static level and reproduces the A.C. component of the D.C. signal of the converter upon the static aD.C. of the A.C. amplifier, and an operational amplifier, one input of which is connected to the A.C. to D.C. converter and one input of which is connected to the A.C. amplifier, to which inputs the A.C. to D.C. converter signal and the signal from the A.C. amplifier are applied to be algebraically summed, whereby the A.C. component of the converter signal is cancelled and a pure D.C. signal analogous to the radiation present at the radiation detector means is produced as the output of the operational amplifier.

Claim 2

A system which generates a D.C. signal proportional to an amount of radioactive energy present at a radiation detector means, including, radiation source and detector means, said detector means arranged to sense the amount of radioactive energy impinging thereupon and to generate electrical pulses proportional thereto, means connected to the detection means to modify the electrical pulses such that each pulse is of equal magnitude and equal time duration, an A.C. to D.C. converter connected to the electrical pulse modifying means to convert the pulses to a D.C. signal having an A.C. component, an A.C. amplifier connected to the A.C. to D.C. converter which produces a D.C. voltage of a predetermined static level and reproduces the A.C. component of the D.C. signal of the converter upon the static aD.C. of the A.C. amplifier, and an operational amplifier, one input of which is connected to the A.C. to D.C. converter and one input of which is connected to the A.C. amplifier, to which inputs the A.C. to D.C. converter signal and the signal from the A.C. amplifier are applied to be algebraically summed, whereby the A.C. component of the converter signal is cancelled and a pure D.C. signal analogous to the radiation present at the radiation detector means is produced as the output of the operational amplifier.

Claim 3

A system which generates an analog D.C. voltage proportional to an amount of radioactive energy present at a radiation detector means, including, a source of radioactivity, means positioned relative to the source to detect the emission from the source, said source and detection means being arranged so that the amount of radioactivity present at the detecting means is proportional to the degree of shielding rendered by a condition of the process susceptible to being sensed by such source and detector means, means connected to the detection means to modify the pulses such that each pulse is of equal magnitude and equal time duration, an A.C. to D.C. converter connected to the modifying means to convert the pulses to a D.C. signal analogous to the condition of the property and necessarily containing an A.C. component proportional to the inherent deviations in the emission impinging upon the detection means, an A.C. amplifier at which the A.C. to D.C. converter signal is applied to produce a D.C. signal of a predetermined static level and to reproduce the A.C. component of the D.C. signal of the converter upon the static D.C. of the A.C. amplifier, and an operational amplifier to one input of which the A.C. to D.C. converter signal is applied and to another input of which the A.C. amplifier signal is applied, the signals thus being algebraically summed, whereby the A.C. component of the D.C. signal from the converter is cancelled and a pure D.C. signal is produced as the output of the system.

Claim 4

A system which generates an analog D.C. voltage proportional to an amount of radioactive energy present at a radiation detector means, including, a source of radioactivity, means positioned relative to the source to detect the emission from the source, said source and detection means being arranged so that the amount of radioactivity present at the detecting means is proportional to the degree of shielding rendered by a condition of the process susceptible to being sensed by such source and detector means, means connected to the detection means to modify the pulses such that each pulse is of equal magnitude and equal time duration, an A.C. to D.C. converter connected to the modifying means to convert the pulses to a D.C. signal analogous to the condition of the property and necessarily containing an A.C. component proportional to the inherent deviations in the emission impinging upon the detection means, an A.C. amplifier at which the A.C. to D.C. converter signal is applied to produce a D.C. signal of a predetermined static level and to reproduce the A.C. component of the D.C. signal of the converter upon the static D.C. of the A.C. amplifier, and an operational amplifier to one input of which the A.C. to D.C. converter signal is applied and to another input of which the A.C. amplifier signal is applied, the signals thus being algebraically summed, whereby the A.C. component of the D.C. signal from the converter is cancelled and a pure D.C. signal is produced as the output of the system.