Radiation sensitive method and means for the determination of areas

Claim 1

APPARATUS FOR THE DETECTION OF ITEMS, COMPRISING TWO SPACED-APART RAY-EMITTING SOURCES, A CONVEYOR EXTENDING BETWEEN SAID SOURCES AND BEING ARRANGED TO BE FREE OF ANY SIGNIFICANT BLOCKING OF RAYS FROM SAID SOURCES AND BEING ADAPTED TO SUPPORT AND MOVE AN ITEM BETWEEN SAID SOURCES, RAY-SCANNING MEANS DISPOSED ON ONE SIDE OF SAID CONVEYOR AND ARRANGED AND LOCATED TO RECEIVE RAYS SEPARATELY AND SIMULTANEOUSLY FROM BOTH SAID SOURCES, MEANS INCLUDED IN THE ONE OF SAID SOURCES ON ONE SIDE OF SAID CONVEYOR FOR EMITTING RAYS INTEMITTENTLY RELATIVE TO THE SCANNING RAYS OF SAID ONE SOURCE, THE OTHER OF SAID SOURCES BEING ARRANGED AND LOCATED TO BE BLOCKED IN EMITTING BETWEEN SAID SOURCES, AND RECORDING MEANS OPERAPASSES BETWEEN SAID SOURCES, AND RECORDING MEANS OPERATIVELY CONNECTED TO SAID RAY-SCANNING MEANS AND SENSING AND RECORDING THE ALTERNATIONS OF EMITTING AND BLOCKING OF RAYS OF SAID RAY-SCANNING MEANS.