Speaker
Description
The Circular Electron Positron Collider (CEPC) aims to test the Standard Model and search for new physics through precision measurements of electroweak, Higgs, and heavy-flavour processes. CEPC plans high-luminosity operation at energies relevant to Higgs, W, and Z boson production, with an expected physics event rate of the order of 100 kHz at the Z pole. Under these conditions, beam-induced backgrounds can produce local hit rates of approximately 100 MHz/cm² in the innermost vertex detector layers. This sustained high hit load requires fast hit acquisition and readout to minimize readout dead time and data loss.
AGORA is a detector concept being developed for CEPC and FCC-ee, with its vertex detector supporting heavy-flavour identification and precision physics measurements. To meet these requirements, its pixel-array readout scheme must process data rapidly and reliably within a limited power budget. Achievable readout performance is constrained by pixel response times, control-signal propagation, and address delivery. These delays affect the coordination of successive readout operations and limit processing speed, motivating a realistic timing description at the architecture design stage.
This work presents a parameterized pixel-array delay model implemented in Verilog for a column-drain readout architecture, supporting the design and validation of digital readout schemes for the AGORA vertex detector. The model incorporates circuit propagation delays into hit storage, readout control, and address transmission. It enables timing studies under different configurations and hit conditions to identify potential readout timing conflicts early in the design process and assess the feasibility of candidate schemes under nonideal timing conditions. Basic functionality has been verified through simulations of isolated hits, priority-ordered multiple-hit readout, and retention of new hits in previously unhit pixels during readout freezes.
This contribution will present the delay modeling approach and representative timing results for AGORA vertex detector readout validation. In particular, it will discuss the effects of pixel response times and signal propagation delays on readout timing, together with the application of the model to identifying potential timing conflicts and validating candidate readout schemes.
