Speaker
Description
The Electron-Ion Collider (EIC) ePIC experiment will employ a Barrel Time-of-Flight (BTOF) detector based on AC-LGAD sensors, which provide excellent time and spatial resolution. The BTOF extends approximately 260 cm along its longitudinal direction. The full length of the BTOF is covered by two FPCs, each approximately 130 cm long. The FPCs are required to have a low material budget in order to minimize their impact on the performance of downstream detectors. We previously developed FPCs for the sPHENIX INTT detector with a signal-line width and spacing of 130 μm and a copper thickness of 12 μm. In this study, we investigate finer signal-line patterns to further reduce the material budget and explore the limits of FPC fabrication. The prototype FPC consists of parallel signal lines extending along its longitudinal direction, and uniformity of the signal-line width is required to ensure stable signal transmission.
Three signal-line widths and spacings of 50, 70, and 100 μm were investigated. In addition, two copper thicknesses, 12 and 18 μm, were evaluated. The fabrication characteristics of these prototype FPCs were comprehensively evaluated using two methods. First, electrical continuity tests were performed to evaluate the uniformity of the resistance among signal lines and to identify short circuits and disconnected circuits. Second, high-resolution camera-based image analysis was used to evaluate the uniformity of the signal-line width and spacing, as well as the fabrication accuracy.
In this presentation, we report the dependence of electrical defects on the signal-line pitch, the variation in signal-line width and spacing, and the effect of copper thickness on the resistance.
