The 2026 International Workshop on the High Energy Circular Electron Positron Collider

First beam test results of COFFEE3, an HV-CMOS Pixel Prototype for the CEPC Inner Tracker

Not scheduled

20m

3rd Floor Hallway

Poster Presentation 07: Silicon Detectors Posters

Speaker

Yuman Cai (IHEP)

Description

COFFEE3 is a 55 nm HV-CMOS pixel detector prototype developed for the CEPC inner tracker. Following previous bench tests with charge injection, laser illumination, and a 55Fe source, two beam-test campaigns were carried out at the CERN SPS in May and July 2026. Clear responses to high-energy charged particles are observed, together with temporal correlation with scintillator reference signals. The measured single-pixel time-of-arrival (TOA) spread is studied and timewalk effect has been observed. Multi-pixel measurements demonstrated the full readout chain of the pixel array and validated the per-pixel threshold-tuning DAC (TDAC) capability. The beam tests also revealed pixel-to-pixel response non-uniformity and noise-induced hit bursts, providing important input for further optimization of COFFEE3 and the development of next-generation HV-CMOS pixel detectors