A Correction Factor to the Two-Bias Method for Determining Mobility-Lifetime Products in Pixelated Detectors

The two-bias method typically used to calculate the mobility-lifetime product (mu tau) in single-polarity charge sensing detectors, uses induced signals from cathode-side events to measure the mu tau. This method assumes an ideal weighting potential (exactly zero through the bulk and a rapid rise to unity at the anode). When a non-ideal weighting potential (e.g., from a pixelated detector) is used, the mu tau is systematically overestimated. In this work, we characterize this overestimation and present a simple correction factor k that can be applied to pixelated electrode configurations. It was found that the correction factor is only dependent on the pixel-pitch to detector thickness ratio.