Radiation thickness gauge using magnetic amplifiers and a constant reference source of voltage for comparison

Claim 1

IN AN ELECTRONIC RAY GAUGE FOR DETERMINING THE THICKNESS OF AN OBJECT DISPOSED BETWEEN A RAY GENERATING APPARATUS AND A RAY DETECTING APPARATUS, WHEREIN SAID DETECTING APPARATUS PUTS OUT A SMALL DETECTOR OUTPUT CURRENT WHICH VARIES WITH THE AMOUNT OF RADIATION REACHING SAID RAY DETECTING APPARATUS, AND THUS WITH THE THICKNESS OF SAID OBJECT; MEANS FOR GENERATING A SMALL, SUBSTANTIALLY CONSTANT CALIBRATION REFERENCE CURRENT OF THE SAME ORDER OF MAGNITUDE AS SAID DETECTOR OUTPUT CURRENT, MAGNETIC AMPLIFIER MEANS FOR AMPLIFYING SAID SMALL CALIBRATION REFERENCE CURRENT, MAGNETIC AMPLIFIER MEANS FOR AMPLIFYING SAID SMALL DETECTOR OUTPUT CURRENT, ELECTRIC CIRCUIT MEANS FOR FEEDING SAID AMPLIFIED DETECTOR OUTPUT AND CALIBRATION REFERENCE CURRENTS, IN OPPOSITION, INTO A THIRD MAGNETIC AMPLIFYING DEVICE, THE AMPLIFIED OUTPUT OF SAID THIRD MAGNETIC AMPLIFYING DEVICE VARYING WITH THE DIFFERENCE BETWEEN SAID AMPLIFIED DETECTOR OUTPUT AND CALIBRATION REFERENCE CURRENTS, AND THEREFORE WITH THE THICKNESS OF SAID OBJECT, AND AN ELECTRIC CIRCUIT MEANS INCLUDING AN INDICATING DEVICE FOR INDICATING SAID THICKNESS.