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Description
For conventional planar strip sensors the interstrip resistance was observed to have a significant variation with ionizing dose and operational temperature. In principle, it could become low enough to result in lateral charge spread across several strips leading to signal loss and deterioration of the positional resolution. There are two aspects of such evaluation that can be improved: 1) The resistance tests are typically done as static IV scans, whereas the realistic signal charge flow is a dymanic process. 2) The criteria used for sensor quality control sometimes use the bias resistor value as a metric for the inter-strip resistance. The bias resistor comparison has a large built-in safety margin since a more relevant metric is the readout amplifiers' input impedance. We sought to establish a more physical criteria for the interstrip resistance evaluation by using SPICE simulation of the sensor model with dynamic signal and a model of readout amplifier. A wide range of the inter-strip resistance values was simulated and its effect on the lateral signal spread was estimated.
