The Space Qualified Read-Out Electronics for the e.m. Calorimeter (ECAL) of the AMS-02 Experiment

The Electromagnetic Calorimeter (ECAL) of the AMS-02 experiment is a fine grained lead-scintillating fiber sampling calorimeter that allows precise, 3-dimensional imaging of the longitudinal and lateral shower development, providing high electron/hadron discrimination ( $\sim 10^{6}$) in combination with the other AMS-02 detectors and a good energy resolution: $\Delta E/E\simeq 10\%/\sqrt {E( {\rm GeV})}$. The ECAL is instrumented with several custom developed electronics subsystems. In addition to the front-end electronics mounted directly on the calorimeter, specific custom boards were developed for supplying high and low voltages and for data acquisition, slow control and trigger. In this article, the ECAL data acquisition, slow control and trigger electronics are described. These boards are composed of two completely independent and separately powered sectors, each capable of carrying out the same functionality. In the case of any fault it is possible to switch from one sector to the other while maintaining full functionality of the ECAL. As for the entire AMS detector, these cards are Space qualified and have been constructed to meet the performance requirements on orbits during 3–5 years of operation.