SU‐FF‐I‐26: Performance Characterization of a New 41cm by 41cm A‐Si Flat Panel X‐Ray Detector

Purpose: To quantify and report the performance of an a‐Si flat panel X‐ray detector with a new generation electronics design in terms of electronic noise, dynamic range and linearity, as well as to quantify the imaging performance such as MTF and DQE. Method and Materials: The new detector was designed to provide low noise, wide dynamic range and programmable gain for a wide signal range. The signal readout chip has 128 channels, and each consists of a charge integration amplifier, followed by a correlated double sampling stage and a 128:1 multiplexer. The output voltage from the multiplexer is digitized by a 16‐bit analog‐to‐digital converter. The programmable gain can provide settings ranging from the most sensitive of ∼250 electrons per counts (e‐/c) to the least sensitive ∼4,000 (e‐/c). The detector uses a 41cm by 41cm a‐Si flat panel with 200μm pixel pitch and was coated with CsI(Tl). The MTF and DQE measurements were carried out in accordance with the IEC standard. Results: The total detector electronic noise is ∼3200 electrons (500 e‐/c), dynamic range was 78.3dB and the non‐linearity is +/−1.5% over 10–90% of full signal scale range. The MTF and DQE were measured both with and without the protective front cover. Conclusion: The detector with the new readout electronics has met all the major design goals and has raised detector performance to a higher level.