A Full-Waveform Digitizer for the Readout of Plastic Scintillator Detectors at HIRFL and HIAF

Abstract

Being among the world’s leading heavy-ion scientific facilities, the heavy ion research facility in Lanzhou (HIRFL) and the high-intensity heavy-ion accelerator facility (HIAF) are constructed to study nuclear physics, atomic physics, nuclide chart, and heavy-ion related applications. Plastic scintillator detectors (PSD) are highly desirable and are used in large amounts for performing the experiments at HIRFL and HIAF. The PSDs are coupled with a photomultiplier tube (PMT) or silicon photomultiplier (SiPM) for converting the photons into electric signals. In this work, we develop a 16-channel full waveform digitizer (FWD) as a standard readout unit for the PSDs at HIRFL and HIAF. The FWD is based on two DRS4 chips. The design of these chips is based on the principle of a switched capacitor array (SCA), which can sample the analog signals at the GHz scale with low power consumption. In addition, the proposed FWD is designed with a general-purpose technique to reduce the development time, production cost, and maintenance difficulties. The laboratory test results show that the proposed FWD is relatively less nonlinear, i.e., about 0.6%. Its time precision is better than 15 ps. The cascade of multiple channels successfully realizes a sampling depth of 2048 cells. The joint test results of PSD show that an excellent performance in terms of measuring the cosmic rays is achieved. This paper presents the design and performance of the proposed FWD.