Front-end readout electronics system of ProtoDUNE-SP LAr TPC

Purpose As a prototype of Deep Underground Neutrino Experiment far detector, ProtoDUNE single-phase Liquid Argon (LAr) Time Projection Chamber (TPC) sits in H4 beam line at CERN to characterize detector response. It consists of 6 full-size Anode Plane Assemblies (APAs) plus 18 Cathode Plane Assembly (CPA) modules to form two 3.6-m drift regions with a total of 15,360 readout channels. To achieve a good signal-to-noise ratio with this noble liquid detector (770ton LAr), cold electronics developed at BNL for extremely low temperature (77K–89K) operation is an optimal solution, which decouples the electrode and cryostat design from the readout design. Methods With CMOS front end ASICs integrated with the TPC electrodes, the electronic noise is independent of the fiducial volume and much lower than with readout electronics at room temperature. In addition, signal digitization and multiplexing to high-speed links inside the cryostat result in large reduction in the quantity of cables and the number of cryostat penetrations, giving the designers of both the TPC and the cryostat the freedom to choose the optimum configurations. Results and conclusions By April 2018, we have successfully instrumented 6 APAs with cold electronics, and the results of the integration test before the final installation in the cryostat look very promising.