Neutron-gamma well-logging apparatus

Claim 1

APPARATUS FOR BORE-HOLE LOGGING COMPRISING A HOUSING ADAPTED TO BE RECEIVED WITHIN A BORE HOLE, A NEUTRON SOURCE MOUNTED WITHIN THE HOUSING, RADIATION DETECTING MEANS MOUNTING WITHIN THE HOUSING AND SPACED AWAY FROM SAID NEUTRON SOURCE, SHIELD MEANS INTERPOSED BETWEEN SAID SOURCE AND SAID DETECTING MEANS OPERATIVE TO PREVENT RADIATION FROM SAID SOURCE FROM IMPINGING DIRECTLY ON SAID DETECTING MEANS, MEANS FED BY SAID DETECTING MEANS OPERATIVE TO DEVELOP FIRST AND SECOND ELECTRIC PULSES RESPECTIVELY REPRESENTATIVE OF FIRST AND SECOND RADIATIONS DETECTED BY SAID DETECTING MEANS, THE REPETITION RATE OF SAID FIRST AND SECOND PULSES BEING RESPECTIVELY PROPORTIONAL TO THE FIELD INTENSITIES OF SAID FIRST AND SECOND RADIATIONS, MEANS FOR TRANSMITTING SAID PULSES TO THE EARTH''S SURFACE, AND MEANS COMPRISING AN ELONGATED MAGNETIC RECORDING MEDIUM, MEANS PLACED ADJACENT SAID MEDIUM FOR RECORDING MAGNETIC IMPRESSIONS THEREON, MEANS FED AND CONTROLLED BY SAID FIRST ELECTRIC PULSES FOR MOVING SAID MAGNETIC MEDIUM PAST SAID RECORDING MEANS AT A RATE PROPORTIONAL TO THE REPETITION RATE OF SAID FIRST ELECTRIC PULSES, MEANS FEEDING SAID SECOND ELECTRIC PULSES TO SAID RECORDING MEANS OPERATIVE TO RECORD ON SAID MEDIUM MAGNETIC IMPRESSIONS PROPORTIONAL IN NUMBER TO SAID SECOND ELECTRIC PULSES, AND MEANS FOR DEVELOPING FROM SAID RECORDING MEDIUM AN INDICATION PROPORTIONAL TO THE NUMBER OF MAGNETIC IMPRESSIONS ON SAID MEDIUM PER UNIT LENGTH THEREOF.