WA104

WA104
Name	WA104
Type	Particle physics experiment
Location	CERN
Established	2016
Status	Operational
Collaborators	CERN, Gran Sasso National Laboratory, ICARUS, FNAL, INFN
Lead institution	ETH Zurich
Detectors	Liquid Argon Time Projection Chamber

WA104

WA104 is a particle physics project hosted at CERN that advanced the deployment of large-scale liquid argon time projection chambers (LAr-TPCs) and precision neutrino detection technologies. The program built on prior efforts at Gran Sasso National Laboratory, leveraged expertise from ICARUS and FNAL initiatives, and acted as a testbed for detectors intended for long-baseline experiments like DUNE and short-baseline programs at Fermilab. WA104 integrated cryogenics, readout, and calibration systems to demonstrate performance metrics relevant to future underground and accelerator-based facilities.

Overview

WA104 concentrated on constructing and operating a ton-to-kiloton scale Liquid Argon Time Projection Chamber prototype at CERN to validate techniques for neutrino physics and rare-event searches. The project connected efforts from institutions such as ETH Zurich, INFN, STFC, University of Oxford, and Politecnico di Milano to address challenges encountered in deployments at Gran Sasso National Laboratory and proposed installations in the United States and Japan. WA104 served both as an R&D platform and as a component in campaigns related to beam tests, cosmic-ray studies, and detector characterization relevant to experiments like ProtoDUNE and SBND.

Design and Construction

Design choices for WA104 were informed by results from ICARUS operations at Gran Sasso National Laboratory and technological developments from ProtoDUNE at CERN's North Area. The mechanical architecture combined a modular cryostat inspired by Membrane cryostat technology and field cage designs tested in MicroBooNE and SBND. Construction phases involved cryogenic engineering teams from INFN and ETH Zurich, instrumentation specialists from CERN and FNAL, and manufacturing partners in Italy and Switzerland. QA procedures referenced standards used in DUNE prototype campaigns, and safety reviews engaged regulatory bodies in France and Switzerland.

Scientific Objectives

WA104 aimed to demonstrate long electron drift lifetimes, precise charge readout, and scalable light detection that would enable oscillation measurements in experiments like DUNE and sterile neutrino searches connected to MiniBooNE anomalies. Secondary objectives included development of low-noise cold electronics inspired by MicroBooNE and evaluation of calibration strategies used in ICARUS and ArgoNeuT. The program also targeted cross-section measurements useful to T2K and NOvA analyses, and provided R&D data for background mitigation techniques relevant to searches modeled after GERDA and CUORE approaches.

Detector Components

The WA104 detector suite comprised a cryostat, a Liquid Argon Time Projection Chamber, photon detection system, cold electronics, and high-voltage distribution inspired by layouts in ICARUS and ProtoDUNE. The TPC used wire-plane or pixelated charge readout geometries similar to those developed for ArgonCube and SBND, while the light collection system integrated wavelength-shifting plates and silicon photomultipliers analogous to implementations in MicroBooNE and DUNE. Cryogenics and purification subsystems were adapted from industrial practices employed in LNG handling and designs tested at Gran Sasso National Laboratory. Detector calibration made use of radioactive sources and cosmic muon tracking methods refined by ICARUS and MINERvA collaborations.

Data Acquisition and Analysis

WA104's data acquisition architecture combined FPGA-based front-end aggregation techniques used in CERN experiments with cold preamplifier designs pioneered at FNAL. Triggering schemes blended continuous readout approaches explored by ProtoDUNE and selective triggering strategies from MicroBooNE. Data workflows employed software frameworks compatible with analysis stacks developed for DUNE and reconstruction algorithms influenced by LArSoft and ROOT-based toolchains. Analysis efforts focused on signal extraction, noise characterization, and track/shower reconstruction benchmarks that interface with oscillation fits used by NOvA and cross-section fits used by T2K.

Collaborations and Funding

WA104 brought together national laboratories and universities including CERN, Gran Sasso National Laboratory, FNAL, ETH Zurich, INFN, University of Oxford, and Politecnico di Milano. Funding sources combined national research agencies like INFN, Swiss National Science Foundation, and STFC with institutional support from CERN and contributions coordinated with DOE-funded programs at Fermilab. The collaboration structure mirrored governance models used in DUNE and ICARUS consortia, featuring institutional boards, technical coordination groups, and publication committees derived from best practices at CERN.

Timeline and Status

WA104 was proposed and prototyped in the mid-2010s, with construction and commissioning phases occurring around the late 2010s and early 2020s, paralleling timelines for ProtoDUNE and ICARUS refurbishments. Commissioning exploited beam test campaigns and cosmic-ray datasets similar to those used by ProtoDUNE and MicroBooNE to validate detector performance. As of the early 2020s WA104 had achieved operational milestones in cryogenics, drift lifetime, and readout stability, and its results informed design choices for larger programs like DUNE and upgrades at Fermilab.

Category:Particle physics experiments