Periodic Reporting for period 2 - DarkWave (Novel technologies for dark matter search and frontier astroparticle physics experiments)
Période du rapport: 2022-01-01 au 2023-09-30
Experimental astroparticle physics is currently one of the most vibrant and exciting areas of fundamental physics and in the coming decade there is a real potential to experimentally resolve two remaining big puzzles in our understanding of the Universe: the nature of dark matter (DM) and the Baryon Asymmetry of the Universe, i.e. why there is more matter than antimatter.
We currently do not know what is the nature of 95% of the energy density of our Universe. Astronomical observations tell us that at least 23% of the unknown density should behave like matter – as we cannot see it, we call it dark matter. The exact nature of DM (and dark energy) is still unknown and its origin is at present one of the most important questions in physics. Particle physics beyond the Standard Model provides several candidate particles which could be the DM. Out of these, Weakly Interacting Massive Particles (WIMPs) are the best motivated. Discovering them would be a major breakthrough and a sign of physics beyond the Standard Model.
The DarkWave consortium made some key contributions towards answering these questions by: (1) building DarkSide-20k, the next generation experiment searching for dark matter via elastic scattering of dark matter particles in liquid argon (LAr), with sensitivity two orders of magnitude beyond current searches, (2) developing new technologies for ARGO and DarkSide-LM, the ultimate detectors, able to probe the full parameter space where WIMPs can be found. It also (3) exploited technological synergies with two other key areas in astroparticle physics: long-baseline neutrino oscillation experiments (DUNE) and gravitational wave detection.
In line with the Twinning work programme goals, the DarkWave project strengthened the scientific and technological profile of Astrocent/NCAC, the coordinating institution, through collaboration with leading international partners (APC/CNRS, GSSI, TUM, INFN), enabling active collaboration through joint activities, personnel exchange and training. Key components of that are:
* practical training of Astrocent/NCAC young research personnel achieved through direct participation (short visits and secondments) in R&D,
* enhancement of administration skills at the coordinating institution through dedicated training.
Pursuing the described science program, aimed at the most stimulating questions in physics, has a very strong potential for rapid technological advances, innovation and creating sustainable links with industry and society, via their applications e.g. in medicine.
We currently do not know what is the nature of 95% of the energy density of our Universe. Astronomical observations tell us that at least 23% of the unknown density should behave like matter – as we cannot see it, we call it dark matter. The exact nature of DM (and dark energy) is still unknown and its origin is at present one of the most important questions in physics. Particle physics beyond the Standard Model provides several candidate particles which could be the DM. Out of these, Weakly Interacting Massive Particles (WIMPs) are the best motivated. Discovering them would be a major breakthrough and a sign of physics beyond the Standard Model.
The DarkWave consortium made some key contributions towards answering these questions by: (1) building DarkSide-20k, the next generation experiment searching for dark matter via elastic scattering of dark matter particles in liquid argon (LAr), with sensitivity two orders of magnitude beyond current searches, (2) developing new technologies for ARGO and DarkSide-LM, the ultimate detectors, able to probe the full parameter space where WIMPs can be found. It also (3) exploited technological synergies with two other key areas in astroparticle physics: long-baseline neutrino oscillation experiments (DUNE) and gravitational wave detection.
In line with the Twinning work programme goals, the DarkWave project strengthened the scientific and technological profile of Astrocent/NCAC, the coordinating institution, through collaboration with leading international partners (APC/CNRS, GSSI, TUM, INFN), enabling active collaboration through joint activities, personnel exchange and training. Key components of that are:
* practical training of Astrocent/NCAC young research personnel achieved through direct participation (short visits and secondments) in R&D,
* enhancement of administration skills at the coordinating institution through dedicated training.
Pursuing the described science program, aimed at the most stimulating questions in physics, has a very strong potential for rapid technological advances, innovation and creating sustainable links with industry and society, via their applications e.g. in medicine.
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.
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.
Novel silicon-based photodetectors equipped with integrated and digital readout, will be applicable to e.g. medical imaging (TOF-PET). ARIA has the capacity to extract isotopes for medical applications. Inexpensive and scalable WLS solution, as well as the novel seismic and infrasound sensors, have wide applications in experimental physics and beyond (photovoltaics, civil engineering), have resulted in creating new long term collaborations, and have potential for commercialization. We keep the general public informed about the exciting science, which is at the core of the project, as well as about its potential applications in everyday life, through public outreach. Finally, in addition to this, training - through activities within the DarkWave project - highly qualified personnel stimulates economic growth in a longer perspective.