Severe hazards in two dimensional position sensing using wedge & strip and Backgammon based patterns

The most unfavorable phenomenon in 2D position sensing is the readout dependence of the two independent dimensions (X, Y). The patterned cathodes, such as the wedge-and-strip, Backgammon, Chevron and Triple Charge Division patterns, are very sensitive to the source displacement perpendicular to their position sensitive directions (X). This sensitivity results in severe dependance for the horizontal readout to the vertical readout. The predicted deviation due to vertical displacements of a given source, which is experimentally confirmed shows that the deviation varies with the source displacement along the X axes. This deviation has a maximum value (about 10% of the full length) at the center of the pattern. Since the deviation varies along the X direction, finding a transfer function for correcting the readout is impossible. Using the patterned cathodes in multi wire proportional counters are possible if the wire spacing is a multiple of the pattern width. Also, these cathodes can be used for two dimensional position sensing, without any limitation, if the readout position in the other dimension is done using drift times of the primary electrons. Using this combination, a high resolution (.25 mm) safe 2D ray trace type patterned telescope was manufactured for particle detection with low threshold energy.