Periodic Reporting for period 1 - DarkWave (Novel technologies for dark matter search and frontier astroparticle physics experiments)
Reporting period: 2020-10-01 to 2021-12-31
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 aims to make key contributions towards these discoveries 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 will also (3) exploit 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 strengthens 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.
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 aims to make key contributions towards these discoveries 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 will also (3) exploit 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 strengthens 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.
The main highlights for each work package (WP) after the first reporting period are summarised below.
WP1 (Management and coordination) is 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 are regularly updated with project-related news and materials. We have also engaged in public outreach, contributing to three events. 8 high impact publications, including 2 conference proceedings papers, were published and 3 more papers submitted for publication since the beginning of the project. In addition to this, 9 project-related conference talks or posters were presented at international conferences. The main achievement is the privilege of organising the next conference LIDINE (LIght Detection In Noble Elements) at Astrocent in September 2022.
As part of WP2 (Analysis and Simulation) we established a well trained team of analysts, which includes postdocs and students from beneficiary institutions, among other members of the DarkSide-20k collaboration. Development of software and analysis/simulation tools, including event reconstruction algorithms and silicon photomultiplier (SiPM) response simulation, including full optical model, was completed and for pulse shape discrimination model is on track. These results are essential for DarkSide-20k, and of high interest for the scientific community.
In WP3 (DarkSide-20k construction), despite a significant delay caused by the COVID-19 pandemic, the DarkSide-20k collaboration has prepared a Technical Design Report, which included significant modifications, simplifying the design and streamlining construction. Modifications particularly relevant for DarkWave concern the Veto design: (1) a greatly simplified geometry of the Veto detector, (2) use of SiPM modules with ASIC-based integrated analog readout, and (3) use of a new wavelength shifting (WLS) material, PEN, based on the proposal from Astrocent, accepted by the collaboration, validated experimentally. This work has attracted interest from the community and a similar approach is now adopted/considered also by other experiments. Preparations for mass production and testing of SiPMs for the veto are advanced, with cryogenic tests ongoing at INFN Genova and prepared at Astrocent. Finally, the ARIA cryogenic distillation facility for purification of 39Ar-depleted underground argon has for the first time successfully operated with argon.
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 already in the DarkSide-20k detector, in the Veto subsystem. Room temperature and cryogenic tests of a pilot series of modules for the Veto have been successful. Design and prototyping of a digital integrated readout for other applications is in progress. Long term student secondment allowed the coordinator institution to gain skills necessary to continue this activity locally. The analogue readout will be immediately exploited for the DarkSide-20k experiment, while the novel digital readout enables construction of larger and/or radiopure detectors that will reach the ultimate WIMP sensitivity in the future.
In 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. A review paper on WLS in LAr detectors was published, and we contributed to R&D for PEN and pyrene WLS, with two technical papers. For PEN, in addition to successful proof-of-principle measurements in LAr, a novel application in WLS transparent FAT-GEM detectors for high pressure noble element TPCs was demonstrated. Otherwise, a novel type of infrasound microphone was developed and networks of such devices have been used for measurements at Virgo (Pisa). GSSI and Astrocent teams performed a seismic site survey at the Einstein Telescope candidate site at Sos Enattos, in Sardinia.
WP1 (Management and coordination) is 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 are regularly updated with project-related news and materials. We have also engaged in public outreach, contributing to three events. 8 high impact publications, including 2 conference proceedings papers, were published and 3 more papers submitted for publication since the beginning of the project. In addition to this, 9 project-related conference talks or posters were presented at international conferences. The main achievement is the privilege of organising the next conference LIDINE (LIght Detection In Noble Elements) at Astrocent in September 2022.
As part of WP2 (Analysis and Simulation) we established a well trained team of analysts, which includes postdocs and students from beneficiary institutions, among other members of the DarkSide-20k collaboration. Development of software and analysis/simulation tools, including event reconstruction algorithms and silicon photomultiplier (SiPM) response simulation, including full optical model, was completed and for pulse shape discrimination model is on track. These results are essential for DarkSide-20k, and of high interest for the scientific community.
In WP3 (DarkSide-20k construction), despite a significant delay caused by the COVID-19 pandemic, the DarkSide-20k collaboration has prepared a Technical Design Report, which included significant modifications, simplifying the design and streamlining construction. Modifications particularly relevant for DarkWave concern the Veto design: (1) a greatly simplified geometry of the Veto detector, (2) use of SiPM modules with ASIC-based integrated analog readout, and (3) use of a new wavelength shifting (WLS) material, PEN, based on the proposal from Astrocent, accepted by the collaboration, validated experimentally. This work has attracted interest from the community and a similar approach is now adopted/considered also by other experiments. Preparations for mass production and testing of SiPMs for the veto are advanced, with cryogenic tests ongoing at INFN Genova and prepared at Astrocent. Finally, the ARIA cryogenic distillation facility for purification of 39Ar-depleted underground argon has for the first time successfully operated with argon.
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 already in the DarkSide-20k detector, in the Veto subsystem. Room temperature and cryogenic tests of a pilot series of modules for the Veto have been successful. Design and prototyping of a digital integrated readout for other applications is in progress. Long term student secondment allowed the coordinator institution to gain skills necessary to continue this activity locally. The analogue readout will be immediately exploited for the DarkSide-20k experiment, while the novel digital readout enables construction of larger and/or radiopure detectors that will reach the ultimate WIMP sensitivity in the future.
In 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. A review paper on WLS in LAr detectors was published, and we contributed to R&D for PEN and pyrene WLS, with two technical papers. For PEN, in addition to successful proof-of-principle measurements in LAr, a novel application in WLS transparent FAT-GEM detectors for high pressure noble element TPCs was demonstrated. Otherwise, a novel type of infrasound microphone was developed and networks of such devices have been used for measurements at Virgo (Pisa). GSSI and Astrocent teams performed a seismic site survey at the Einstein Telescope candidate site at Sos Enattos, in Sardinia.
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, will have wide applications in experimental physics and beyond, potential for creating new long term collaboration, and 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.