Gridded duo-lateral position sensitivity detector with high linearity to low energetic electrons in vacuum environment

Characterising a position sensitive detector in a vacuum environment without beam position monitoring devices can be challenging and expensive. With this in mind, the authors have designed and fabricated a duo-lateral position sensitive detector (PSD) incorporated with simple and inexpensive surface features. It was evaluated using scanning electron microscopy. To assist in pinpointing precise positioning as well as acting as path guide during the sweeping of electrons, multiple grids were lithographically patterned on the top layer of the duo-lateral PSD. By sweeping electrons along two axes of the detector, the position detection error of both axes was determined from the signals recorded using a transimpedance amplification circuit. They were able to characterise the linearity over the x- and y-axis of the PSD and the results show a very high linearity over two-dimensions of the PSD´s active area and that accurate beam monitoring for spectroscopic measurement without additional beam position monitoring devices is possible.