ASICs for Belle II pixel detector (KEK, Japan) - DCD and SWITCHER

Belle II Experiment – Advancing Particle Physics


Belle II is a cutting-edge experiment conducted at the SuperKEKB accelerator (KEK, Tsukuba, Japan). Its primary goal is to measure the decay time of B mesons and anti-B mesons, providing critical insights into particle-antiparticle asymmetry.
In collaboration with our partners, ADL has developed the vertex detector for Belle II, utilizing DEPFET sensor technology for high-precision measurements.


Advanced Readout and Control Electronics


To operate and read out the sensors, three specialized ASICs are used:

  • SWITCHER – Generates high-voltage signals to activate and deactivate pixel rows.
  • DEPFET Current Digitizer (DCD) – Amplifies and digitizes sensor signals.
  • Data Handling Processor (DHP) – Processes the digital amplitudes provided by the DCD.

ADL was responsible for the development and production of SWITCHER and DCD ASICs. Key specifications include:

  • DCD: Integrates 256 8-bit ADCs, sampling at a 100 ns period.
  • SWITCHER: Features 32 high-voltage channels, generating fast 10 ns signals with amplitudes of up to 20V.
DEPFET detector with DCD and SWITCHER ASIC prototypes

Project Support & Timeline

The project was funded by BMBF. The Belle II experiment officially commenced in March 2019, marking a significant milestone in precision particle physics research.