Design and performance of a 35-ton liquid argon time projection chamber as a prototype for future very large detectors

Abstract

Liquid argon time projection chamber technology is an attractive choice for large neutrino detectors, as it provides a high-resolution active target and it is expected to be scalable to very large masses. Consequently, it has been chosen as the technology for the first module of the DUNE far detector. However, the fiducial mass required for "far detectors" of the next generation of neutrino oscillation experiments far exceeds what has been demonstrated so far. Scaling to this larger mass, as well as the requirement for underground construction places a number of additional constraints on the design. A prototype 35-ton cryostat was built at Fermi National Acccelerator Laboratory to test the functionality of the components foreseen to be used in a very large far detector. The Phase I run, completed in early 2014, demonstrated that liquid argon could be maintained at sufficient purity in a membrane cryostat. A time projection chamber was installed for the Phase II run, which collected data in February and March of 2016. The Phase II run was a test of the modular anode plane assemblies with wrapped wires, cold readout electronics, and integrated photon detection systems. While the details of the design do not match exactly those chosen for the DUNE far detector, the 35-ton TPC prototype is a demonstration of the functionality of the basic components. Measurements are performed using the Phase II data to extract signal and noise characteristics and to align the detector components. A measurement of the electron lifetime is presented, and a novel technique for measuring a track's position based on pulse properties is described.

First results on ProtoDUNE-SP liquid argon time projection chamber performance from a beam test at the CERN Neutrino Platform

“…The argon purification system is the largest constructed to date. As compared to previous devices, such as ICARUS [2], ArgoNeuT [7], LongBo [8], MicroBooNE [9], and the 35-ton prototype [10] which had shorter maximum drift distances, the 3.6 m drift distance in ProtoDUNE-SP makes higher demands on argon purity. Under the nominal electric field of 500 V/cm, the maximum electron drift time is 2.25 ms.…”

Design, construction and operation of the ProtoDUNE-SP Liquid Argon TPC

“…The Reconfigurable Cluster Elements (RCE) [40] based readout, developed by the SLAC National Accelerator Laboratory, is a full meshed distributed architecture, based on networked SoC elements on the ATCA platform. The RCE was chosen as the baseline readout solution for ProtoDUNE-SP since it had already been successfully used in the 35 ton prototype [41], and during ProtoDUNE-SP's beam run it read out five of the six APAs (12,800 channels). RCE-based readout focuses on early data processing, with tightly coupled custom firmware and software implementations.…”