Self calibrating radiometer with both reference source and test source interrupted by one chopper and reference source interrupted by a second chopper

Claim 1

A SELF-CALIBRATING RADIOMETER FOR NONSYNCHRONOUS SYSTEMS COMPRISING, A RADIATION DETECTOR FOR RECEIVING AND INDICATING THE VARIATION OF THE ENERGY LEVEL RELATIVE TO A PREDETERMINED REFERENCE LEVEL RELATIVE TO RADIATION RECEIVED FROM A DISTANT RADIATION SOURCE, A CALIBRATING RADIATION SOURCE HAVING A PREDETERMINED RADIATION LEVEL FOR DIRECTING CALIBRATING RADIATION THEREFROM INTO SAID RADIATION DETECTOR, A "FAST" CHOPPER DISPOSED IN FRONT OF SAID DETECTOR FOR SUCCESSIVELY INTERRUPTING AND PASSING RADIATION FROM THE DISTANT RADIATION SOURCE AND FROM THE CALIBRATING RADIATION SOURCE AT A UNIFORM RAPID RATE, AND A SEPARATE SLOW CHOPPER DISPOSED TO INTERRUPT RADIATION ONLY FROM THE CALIBRATING RADIATION SOURCE, SUCCESSIVELY AT A MATERIALLY SLOWER UNIFORM RATE THAN THE RATE OF INTERRUPTION OF RADIATION FROM THE DISTANT RADIATION SOURCE, BY SAID FAST CHOPPER.