The Concept of the ArgonCube TPC module
The central idea is to construct and position separate yet identical modules, each with external dimensions of 0.67 x 0.67 x 1.8 m3, in a common bath of liquid argon. Each module features a relatively short drift length and a fully independent TPC with its own readout, light detection system, cryogenics, and services. Module walls are thin enough to be transparent to electromagnetic and hadronic showers as well as neutrino produced primary particles. This detector configuration allows for an optimal use of the liquid argon with a relatively large fraction of active volume, compared to other implementations of the technology. The short drift length permits a less stringent requirement on the liquid argon purity and helps to reduce event pile-up.
The standard charge readout method for liquid argon TPCs uses consecutive planes of sensing wires to measure two of the three space coordinates. Although the concept is proven, it has an intrinsic limitation in resolving ambiguities, which make event reconstruction difficult. In addition, the construction and mounting of wire planes is expensive and limits TPC design. An alternative to the wire readout would be advantageous. A single readout electrode separated into pixels of a size comparable to the standard wire spacing is the most compelling option. The number of pixels for equal spatial resolution will be two or three orders of magnitude higher than the number of sense wires, with a corresponding increase of the number of signal channels, data rates and power dissipation. This would make such a solution untenable except for small detectors. A readout scheme that reduces these issues to a reasonably low level is being developed for ArgonCube.
The Figure below shows a schematic drawing of the basic module