Method of and apparatus for radioactivity well logging

Claim 1

IN COMBINATION WITH A RADIATION RECEIVING AND DETECTING DEVICE ADAPTED TO BE LOWERED INTO A BORE HOLE AND HAVING A PULSE OUTPUT, A TRANSISTOR PULSE DISCRIMINATING MEANS COMPRISING FIRST AND SECOND TRANSISTOR STAGES, WHEREIN SAID FIRST STAGE INCLUDES A FIRST TRANSISTOR HAVING A FIRST EMITTER, A FIRST BASE AND A FIRST COLLECTOR, A FIRST RESISTANCE MEANS CONNECTING SAID FIRST EMITTER TO GROUND POTENTIAL, A SECOND RESISTANCE MEANS CONNECTING SAID FIRST COLLECTOR TO A POSITIVE POTENTIAL, A THIRD RESISTANCE MEANS CONNECTING SAID FIRST COLLECTOR TO SAID FIRST BASE, AND A FIRST CAPACITANCE MEANS CONNECTED AT ONE SIDE TO SAID FIRST BASE AND CONNECTED AT THE OTHER SIDE TO THE OUTPUT CONNECTION OF SAID RADIATION DETECTING DEVICE, AND WHEREIN SAID SECOND STAGE INCLUDES A SECOND TRANSISTOR HAVING A SECOND BASE, A SECOND COLLECTOR AND A SECOND EMITTER, A WIRE MEANS CONNECTING SAID EMITTER TO GROUND POTENTIAL, A FIFTH RESISTANCE MEANS CONNECTING SAID SECOND COLLECTOR TO SAID SOURCE OF POSITIVE POTENTIAL, A SIXTH RESISTANCE MEANS CONNECTING SAID SECOND BASE TO SAID SOURCE OF POSITIVE POTENTIAL, A SECOND CAPACITANCE MEANS CONNECTING SAID SECOND RESISTANCE MEANS TO SAID SIXTH RESISTANCE MEANS AT POINTS BETWEEN SAID COLLECTORS AND SAID RESISTANCE MEANS, AND WHEREIN A THIRD CAPACITANCE MEANS CONNECTS SAID SECOND COLLECTOR TO SAID FIRST BASE.