Status report on Chimneys

Task 9.3 foresees the study of a novel charge readout scheme for very large liquid-argon time projection chambers named Vertical Drift. This technology avoids using wires to collect the signals of the electrons from charged-particle ionization, at the end of their drift path. Wire planes are instead replaced by stacks of perforated printed circuit boards integrated in charge readout planes of 3x3.3 m² placed to cover the surface at the top of the detector. This active surface receives the electrons drifting thanks to a uniform electric field aligned along the vertical axis. The cryogenic ASIC amplifiers used to read the signals are integrated in this layout in front-end cards by hosted-in-cryostat penetrations ‘signal feedthrough chimneys” which make them accessible from outside during detector operation. The digitization electronics at warm are cabled to warm flanges closing the top part of the chimneys. This technology, which is foreseen to equip the second DUNE Far Detector module, underwent extensive large-scale tests at the CERN Neutrino Platform in 2021-2022. These tests successfully demonstrated its validity. This milestone reports about the work and developments performed on the chimneys.