P. H. Broerse
1966
Citations
0
Influential Citations
2
Citations
Journal
Advances in electronics and electron physics
Abstract
Publisher Summary Lead monoxide is one of the materials that show a high target gain in bombardment induced conductivity. It was felt that it might be interesting to investigate this property of PbO that is known as an excellent photoconductor for camera tubes. The most important property of the PbO layer in this tube is the target gain is/ip, where is is the signal current induced by the primary electron current ip. An aluminum layer with an area density of about 15 μg/cm2 is evaporated onto the foil to serve as a signal-plate. This layer also prevents excitation of the PbO by photons. Although in principle the focusing of an electrostatic image converter is independent of the applied potential, a separate focusing electrode is used, thus making sure that, with primary potentials ranging from 6 to 26 kV, the electron image can be brought into focus. Moreover, when the evaporation circumstances are appropriately chosen, lead oxide can be made n-type or p-type as required. If evaporated in a vacuum, PbO proves to be n-type due to oxygen vacancies. Therefore evaporation in oxygen is a means of controlling the conductivity type of the layer.