The main highlights for each work package (WP) are summarised below.
WP1 (Management and coordination) was devoted to financial and administrative tasks, coordinating travels, and project meetings. To improve management skills at Astrocent, several training sessions were organised, both in Poland and abroad. A project website and a twitter profile were created and regularly updated with project-related news and materials. We have also engaged in public outreach, contributing to three events. 22 high impact publications, including 4 conference proceedings papers, were published and several more papers submitted for publication since the beginning of the project. In addition to this, over 60 project-related conference talks or posters were presented at international conferences. Astrocent hosted the LIDINE 2022 (LIght Detection In Noble Elements) conference, which was a major success.
As part of WP2 (Analysis and Simulation) we established a well trained team of analysts. Development of software and analysis/simulation tools, including event reconstruction algorithms and silicon photomultiplier (SiPM) response simulation, including full optical model, and similarly the pulse shape discrimination model for SIPMs and the final neutron background level and sensitivity estimates for the experiment were completed. These results are essential for DarkSide-20 and for the scientific community, and resulted in publications, multiple conference contributions and 2 PhD thesis.
In WP3 (DarkSide-20k construction), despite a significant delay caused by the COVID-19 pandemic, the DarkSide-20k detector is now well advanced in construction phase. The contributions to that endeavor from the DarkWave project include: (1) use of a new wavelength shifting (WLS) material, PEN, based on the proposal from Astrocent, accepted by the collaboration, validated experimentally and procured, (2) cryogenic test stands at Astrocent for veto photodetector and wavelength shifter quality control, (3) participation in mass production and testing of SiPMs, and (4) operation of ARIA cryogenic distillation facility for purification of 39Ar-depleted underground argon, which has for the first time successfully operated with argon. Success of these contributions attracted new collaborators and resulted in multiple new grant applications, some successful.
In WP4 (Novel SiPM development) successful performance, demonstrated with room temperature and cryogenic tests, of the integrated analog SiPM readout based on a new chip motivated employing them in the Veto subsystem of the DarkSide-20k detector. A follow-up prototype of a digital integrated readout for other applications was then completed to enable construction of larger and/or radiopure detectors that will reach the ultimate WIMP sensitivity in the future. Long term student secondment allowed the coordinator institution to gain skills necessary to continue this activity locally. Potential for applications of digital SiPMs for medical applications (time-of-flight PET) is now being exploited by the 3DPi collaboration.
WP5 (Scale-up and synergies) is focused on main challenges in scaling up noble liquid detectors to multi-hundred tonne size and on synergies with gravitational wave experiments. Multiple papers were published, including a review and several technical papers on wavelength shifters for liquid argon detectors. For PEN wavelength shifter, in addition to successful proof-of-principle measurements in liquid argon, a completed large-scale test at CERN, and a novel application of WLS transparent FAT-GEM detectors for noble element TPCs, applications in industry are now being explored. Otherwise, a novel type of infrasound microphone was developed and networks of such devices were used for measurements at Virgo. A seismic site survey at the Einstein Telescope candidate site at Sos Enattos, in Sardinia, as well as at LNGS in the DarkSide-20k location were performed. Apart from multiple publications, 3 patents related to these sensors were submitted.
