Characterizing and controlling temperature-dependent gains of GODDESS preamplifiers via active cooling

The GODDESS detector system detects charged particles in coincidence with gamma rays emitted in beam experiments at DOE User Facilities, such as ATLAS and FRIB. These typically run over multiple weeks or months to inform on nuclear structure and to constrain nuclear reaction rates important for astrophysical processes. Therefore, gain-stability over long periods is important. A critical component in the electronics are charge-sensitive preamplifiers, which amplify the small signals from the silicon detectors. These preamplifiers generate heat, and because they have limited passive ventilation, they have previously been force-air cooled by constant fans. Because they exhibit temperature-dependent gains, and room temperature is not stable over long periods, in-situ gain drifts have been observed that degrade total resolution. To combat this, an active approach to cooling has been investigated and prototyped. This approach uses temperature sensors, microcontrollers, and motor drivers, to measure the preamplifier temperature and modulate airflow in order to compensate for external changes. Analysis of the temperature dependency of the preamplifier gain, and details of the prototype temperature readout and active-control cooling system and its performance will be presented.

Work supported in part by U.S. Department of Energy.