title: Design, Construction and Initial Characterisation of ARIADNE – A Novel Dual-Phase LArTPC with an Optical Readout System, and Development towards Light Readout Planes for Optical, Large-Scale, Dual-phase, LArTPCs within the Neutrino Sector.
Creators: name: Philippou, Barnaby
Publisher: name: University of Liverpool Repository
Year: 2022

description: ARIADNE is a 1-ton (330 kg fiducial mass), dual-phase, liquid argon (LAr), time projection chamber (TPC) with the overarching objective of developing novel optical readout methods for large-scale LArTPCs. The ARIADNE detector features external mounting for optical readout devices, historically four electronmultiplying charge-coupled device (EMCCD) cameras, and more recently incorporation of a single timepix3 (TPX3) camera. These devices capture secondary scintillation light produced in the holes of a thick gaseous electron multiplier (THGEM). Optical readout has the capacity to be a scalable, cost-effective, alternative to charge readout for future LArTPCs. In this paper, the technical design and first-characterisation results of the ARIADNE detector are presented. This includes both cosmic-particle (at the University of Liverpool LAr lab) and secondary beamline sources. ARIADNE represented a first for dual-phase optical readout LArTPCs with mixed particle imaging from the CERN T9 beamline (a secondary beamline from the CERN PS). Novel optical readout results are presented alongside track reconstruction and analysis techniques for both readout devices. Finally, the results of a series of self-contained R&amp;D projects are presented. These prototype investigations were used to inform the production of light readout planes (LRPs), as an alternative to current charge readout planes (CRPs), for large-scale LArTPCs. This includes the production and characterisation of novel Glass THGEMs (G-THGEMs), with indium tin oxide (ITO) electrodes, manufactured via an innovative masked abrasive machining technique. This allows for unprecedented versatility in the design of THGEMs with respect to substrate and electrode material selection, as well as hole layout and geometry. Consequently, a range of THGEM properties can be preferred, for example, high stiffness, low total thickness variation, radiopurity, moisture absorption, outgassing, and/or carbonisation resistance. Furthermore, results from studies that optimise the collection of secondary scintillation light from THGEMs are also displayed. Firstly, the characterisations of different polyethylene naphthalate (PEN) wavelength shifter (WLS) foils were presented as a scalable alternative to current tetraphenylbutadiene (TPB) methods. Because a polyester PEN can be extruded into foils, TPB requires thin-film deposition techniques. Lastly, by combining a TPX3 camera with a VUV sensitive image intensifier, direct readout of THGEM secondary scintillation light was achieved. In closing, a conceptual prototype LRP design was introduced, which will be produced and tested at the CERN ”cold-box” vessel in Spring 2022. This will feature PEN WLS, G-THGEM, and TPX3 cameras and areas of direct VUV readout as a consequence of the work presented in this thesis and will inform future optical readout LArTPCs.