Radioactive well logging system utilizing mechanically controlled pulsed neutron source

Claim 1

IN RADIATION WELL LOGGING, A BOREHOLE SYSTEM FOR PRODUCING PERIODICALLY BURSTS OF PRIMARY RADIATION SPACED IN TIME FOR IRRADIATING THE FORMATION TRAVERSED BY A BOREHOLE AND SENCHRONIZING PULSES FOR CONDITIONING A RADIATION RECORDING SYSTEM COMPRISING: A BOREHOLE UNIT FOR TRAVERSING A BOREHOLE, MEANS INCLUDING CABLE MEANS FOR MOVING SAID BOREHOLE UNIT THROUGH A BOREHOLE, A FIRST MATERIAL LOCATED IN SAID UNIT AND CHARACTERIZED BY THE CONTINUOUS EMISSION OF RADIATION, A SECOND MATERIAL LOCATED IN SAID UNIT FOR EMITTING PRIMARY RADIATION OF A DIFFERENT NATURE WHEN EXPOSED TO RADIATION EMITTED BY SAID FIRST MATERIAL, MEANS LOCATED IN SAID UNIT AND MOUNTED FOR PERIODIC MOVEMENT RELATIVE TO AT LEAST ONE OF SAID MATERIALS TO EXPOSE PERIODICALLY SAID SECOND MATERIAL TO RADIATION EMITTED BY SAID FIRST MATERIAL ONLY DURING PREDETERMINED TIME INTERVALS TO PRODUCE BURSTS OF PRIMARY RADIATION SPACED IN TIME, MEANS LOCATED IN SAID UNIT AND RESPONSIVE TO THE PERIODIC MOVEMENT OF SAID LAST-NAMED MEANS TO A PREDETERMINED POSITION FOR PRODUCING A SYNCHRONIZING PLSE CONCOMITANT WITH EACH OF SAID BURSTS OF PRIMARY RADIATION PRODUCED FROMSAID SECOND MATERIAL WHEN PERIODICALLY EXPOSED TO RADIATION FROM SAID FIRST MATERIAL, DETECTING MEANS LOCATED IN SAID UNIT FOR DETECTING SECONDARY RADIATION RESULTING FROM THE IRRADIATION OF THE FORMATIONS WITH PRIMARY RADIATION, AND MEANS FOR APPLYING THE OUTPUT OF SAID DETECTING MEANS AND THE PULSES PRODUCED BY SAID SYNCHRONIZING MEANS TO SAID RADIATION RECORDING SYSTEM.