A microwave frequency dynamic crossed-field photomultiplier

A new type dynamic secondary emission electron multiplication system is described which possesses the advantages of electrostatic electron multipliers while overcoming their major disadvantage, i.e., loss of gain at high frequencies due to electron transit time dispersion. In the dynamic crossed-field electron multiplication system, electrons are multiplied in a field configuration consisting of a high-frequency electric field and a crossed steady magnetic field near a single secondary emitting electrode. The analysis of the system is presented, and an experimental photomultiplier device is described which utilizes this principle. An experiment is also described in which this photomultiplier is used to directly detect light intensity modulated at a frequency of 3 Gc.