JOURNAL DE PHYSIQUE IV

Abstract: A new style of charge-separation position-sensitive detector has been tested which has similar cost benefits as other charge-separation devices but has an error-awareness capability to provide an increased collection rate. The wedge-on-wedge anode is similar to the wedge-and-strip anode except that the four electrodes possess both wedge and strip character. This provides additional charge infonnation such that a plurality of positional equations occurs. This provides an error-awareness condition if multiple arrivals strike the detector. Initial results of the wedge-on-wedge detector for use as an electronic detector for imaging and analysis for atom probe microscopy are provided. These results indicate that this detector should perform adequately for atom probe microscopy. 1. BACKGROUND Many imaging and analytical techniques require the use of position-sensitive detectors (PSD) for data collection. Several classes of PSDs use the charge cloud produced by microchannel plates (MCP) for position determinations [l]. These classes can be broadly described as discrete anode, charge separation, and hybrid. Discrete anode detectors require that the entire charge cloud land on a single anode. This produces a binary arrival event at the anode location in the discrete anode array. Charge-separation devices require that the charge be divided among several electrodes. The ratio of these charges provide