Hybrid Photomultiplier Tubes Using Internal Solid State Elements

A new family of photomultiplier tubes has been developed using silicon diodes and transistors as multiplying elements. For applications requiring low and medium gains these tubes offer several advantages over tubes utilizing ordinary dynode multiplication. These include ease of fabrication, mechanical ruggedness, reduced sensitivity to magnetic fields, and fast response. Diode structures have provided normal gains up to the theoretical maximum and have exhibited very short response times. In a few cases anomalously high diode gains have been observed, apparently as the result of induced avalanching near the diode front surface. Much greater gains have been obtained from various transistor structures with some sacrifice in the response time.