Cold Electronics System Development for ProtoDUNE-SP and SBND LAr TPC

ProtoDUNE-SP and SBND are both liquid argon (LAr) TPCs for neutrino experiments, they share many common development of cold electronics system. Cold electronics decouples the electrode and cryostat design from the readout design. With front-end (FE) electronics integrated with detector electrodes, the noise is independent of the fiducial volume (signal cable lengths), and much lower than with warm electronics. ProtoDUNE-SP cold electronics mainly consists of 960 FE ASICs, 960 ADC ASICs and 120 cold FPGAs to form 120 Front End Mother Board (FEMB) assemblies. Each FEMB assembly is made up of an analog mother board (AM) and an FPGA mezzanine (FM). An AM has 128 channels with 8 FE ASICs and 8 ADC ASICs designed by BNL for 77K-300K operation and long lifetime with low power consumption. The FM multiplexes and transmits 128 channels of data through four 1 Gb/s serial links to the warm interface electronics. SBND cold electronics mainly consists of 120 FEMB assemblies. The SBND design is exploring two different options, the dual gain ADC option and the commercial ADC option. Market survey and cold screening tests for the op-amp and commercial ADC have been performed to evaluate the feasibility of two options, with focus on the commercial ADC lifetime study currently. An integration test stand with 40% APA (Anode Plane Assembly) has been built at BNL, following the DUNE isolation and grounding rules, to characterize the performance of cold electronics system. The ProtoDUNE-SP installation at CERN is going well, 20 FEMB assemblies have been installed on the first APA successfully, to prepare for the data taking in 2018. SBND front-end readout electronics design will be finalized in 2018, to get ready for the data taking in 2020.