Optimization of 500MHz Pixie Module for Fast Time Measurement

In the CERN summer student programme 2023, I worked on optimization of digital system of 500 MHz pixie in ISOLDE Decay Station (IDS). After obtaining a sorting process available of traces, time resolution of Constant Fraction Discriminator (CFD) was optimized by varying its shape parameters: CFD_Delay and CFD_Scale, and observing the FWHM of time difference of $\gamma-\gamma$ coincidence of 60Co. Simulation suggests the optimized parameters pair as CFD_Delay = 8 ns, and CFD_Scale = 0.25.