Multi-Level Time-Over-Threshold Method for Energy Resolving Multi-Channel Systems

Pixellated radiation detectors require an energy resolving multichannel system. The time-over-threshold (ToT) method provides an inexpensive way to energy-resolving signal processing. However, the conventional, single-threshold ToT method suffers from a small dynamic range and poor linearity. We have studied linearity in a ToT system for typical shaping filters and propose a new, multi-level, ToT scheme. This method provides higher linearity and wider dynamic range. We have analyzed the typical signal cases of triangular, CR-RC, and Semi-Gaussian filters, and achieved a linearity of less ≤3% in Integral Non-Linearity (INL).