Geophysical propecting device for identifying radioactive elements

Claim 1

A DEVICE FOR DETECTING AND IDENTIFYING THORIUM AND URANIUM COMPRISING, IN COMBINATION, A SCINTILLATION GAMMA RAY DETECTOR CAPABLE OF DELIVERING, AT THE OUTPUT THEREOF, ELECTRICAL PULSES OF AN AMPLITUDE SUBSTANTIALLY PROPORTIONAL TO THE RESPECTIVE ENERGIES OF THE INCIDENT GAMMA RAY, PULSE-HEIGHT ANALYZING MEANS HAVING AN INPUT CONNECTED TO THE OUTPUT OF SAID DETECTOR AND AT LEAST FOUR OUTPUTS, SAID PULSE-HEIGHT ANALYZING MEANS BEING ADJUSTED TO SUPPLY ON SAID FOUR OUTPUTS A FIRST, SECOND, THIRD AND FOURTH OUTPUT SIGNAL WHICH ARE INCREASING FUNCTIONS OF THE NUMBER OF OUTPUT PULSES FROM SAID DETECTOR HAVING AMPLITUDES HIGHER THAN THE UPPER LIMIT AMPLITUDE OF THE PARASITIC PULSES DELIVERED BY SAID DETECTOR FOR THE FIRST SIGNAL, THE AMPLITUDE CORRESPONDING TO A GAMMA RAY ENERGY OF APPROXIMATELY 0.7 MEV. FOR THE SECOND SIGNAL THE AMPLITUDE CORRESPONDING TO A GAMMA RAY ENERGY OF APPROXIMATELY 1 MEV. FOR THE THIRD SIGNAL AND THE AMPLITUDE CORRESPONDING TO A GAMMA RAY ENERGY OF APPROXIMATELY 2 MEV. FOR THE FOURTH SIGNAL RESPECTIVELY, ANTICOINCIDENCE PULSE-HEIGHT SELECTING MEANS CONNECTED TO SAID PULSE-HEIGHT ANALYZING MEANS COMPARING SAID SECOND AND SAID THIRD SIGNAL TO SUPPLY A FIRST CURRENT REPRESENTATIVE OF THE NUMBER OF OUTPUT PULSES FROM SAID DETECTOR HAVING AMPLITUDES CORRESPONDING TO GAMMA RAY ENERGIES IN A FIRST BAND SUBSTANTIALLY BETWEEN 0.7 MEV. AND 1 MEV.