Characterization of a compact and cost-effective readout system for germanium detectors.

Germanium semiconductor detectors represent the gold-standard choice for gamma spectroscopy, due to their excellent energy resolution which can be obtained with a proper temperature control. The aim of this contribution is to show a novel method to process, shape and digitize the analog signals coming from a germanium detector, without using the traditional analogic modules. This method is based on the "Red Pitaya STEMlab 125-14" a board which implements in the size of a credit card a CPU, a FPGA, a port for network connections (useful for remote access and control) and two 125 MS/s 14-bit digitizer channels. This system was experimentally tested by acquiring the spectrum of thoriated (2%) welding electrodes with a germanium detector. The system performance resulted to be comparable to the one obtained with the usual optimized electronic chain. The main advantages of this new approach are the compactness, versatility, and low cost, making it ideal also for a portable and high-resolution gamma detector.