Instrumentation Division Seminar

The search for the lepton-flavor violating decay mu+ -> e+ gamma is both attractive and very challenging. It is complementary to direct searches for New Physics at high energy colliders and has a reach up to several 100 TeV, well beyond any current and future accelerator. The challenge in this search at a level down to 10^-14 with the MEG experiment is the huge background coming from normal muon decays, which requires cutting-edge detector technology and electronics. For this purpose, the Switched Capacitor Array (SCA) chip DRS4 has been developed at PSI, Switzerland. With a sampling rate of 5 GSPS at 12 bits of resolution at a power consumption of 15 mW per channel, this technology allows excellent energy and time resolutions down to a few picoseconds for systems with more than 10,000 channels. I will show results from the MEG experiment and the ongoing work for the MEG II upgrade, which seeks to improve the current limit by one more order of magnitude. It covers the theory behind SCA chips and explains its advantages and limitations. I will show the integration of 9000 channels in the new WaveDAQ system, which is a new crate standard combining the best techniques from VME and xTCA, at a much lower complexity and cost. This includes precision clock distribution down to a few pico seconds, crate management, SiPM bias voltage generation, integrated triggering and data collection.