A multi-channel digital acquisition system for Ge spectroscopy in the GERDA experiment

We developed a multi-channel digital acquisition (DAQ) system, able to operate in connection to Germanium-based detectors and state-of-the-art charge sensitive preamplifiers. The DAQ system is composed of up to 6 front-end NIM modules, each one with 4 free running analog to digital converters (100 MHz, 14 bits) and up to 6 custom PCI based receiver boards inside a single personal computer (PC). We also implemented a comprehensive graphical user interface on the user PC and a digital triggering algorithm inside the DAQ system by means of programmable logic devices (FPGA) and a suitable global slow control for the whole system. The performances of the DAQ system in terms of energy resolution, sustained data transfer rate, digital trigger sensitivity, etc. are all within the specifications of the GERDA experiment for Phase-I.