The principle and experimental results of an all electrostatic, no-mesh, return-beam, electron camera readout system

An all electrostatic deflecting lens (EDL), return-beam system has been developed as the read-out section of an electron camera. The most important feature of the EDL system is that there is no field stopping mesh used, which is a design breakthrough in return-beam imaging devices. Due to the elimination of the field stopping mesh, ultra-high resolution becomes possible. The system was tested at electron landing energy ranging from practically "zero" e.v. to 14kv. In a cm raster scan, the typical on-axis modulation transfer function (MTF) at a spatial frequency of 100lp/mm is 0.67 for high-energy landing and 0.55 for low-energy landing. The linear scan is 7,000 spot diameter at high-energy landing and around 6,000 spot diameter at low-energy landing.