Development of the Arapuca technology for hybrid Cherenkov and scintillation detectors: opening the way for the fourth DUNE module

• Grant number: 25/06694-1
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Start date: January 22, 2026
• End date: February 21, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - Elementary Particle Physics and Fields
• Principal Investigator: Ana Amélia Bergamini Machado
• Grantee: Ana Amélia Bergamini Machado
• Visiting researcher: Jose Carvalho Maneira
• Visiting researcher institution: Laboratório De Instrumentação E Física Experimental De Partículas/Lip, Portugal
• Host Institution: Instituto de Física Gleb Wataghin (IFGW). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 19/11557-2 - Light detection system for the DUNE X-ARAPUCA experiment, AP.JP

Abstract

The ARAPUCA technology, invented and developed in Brazil by the host researcher of this project, was chose for the detection of optical photons in 3 (of a total of 4) large far detectors of the Deep Underground Neutrino Experiment (DUNE), presently in construction at Fermilab and SURF, in the USA. That technology is based on the coupling of dichroic filters, wavelength shifting materials and silicon photomultipliers. Its main advantages for use in detector based in liquid argon are its capability of detecting very low wavelengths with good efficiency, resistance to cryogenic use and the possibility of producing thin planar detectors. However the technology's versatility allows its application in other contexts: the C-ARAPUCA variant was developed with the goal of detecting Cherenkov photons in water-based detectors. This work plan intends to test the possibility of taking the concept farther and using the ARAPUCA technology in new hybrid detectors based on liquid scintillators but combining the observation of scintillation with Cherenkov light. That was already achieved in detectors using scintillators with a very low efficiency, focused exclusively on the observation of high energy neutrinos: the challenge is now to achieve the identification of Cherenkov light while keeping a high scintillation efficiency that allows, in addition to the beam neutrinos, the access to a wide range of low energy physics, such as <~ 1 MeV solar neutrinos and neutrinoless double beta decay. The advantage of the simultaneous detection of Cherenkov light is the sensitivity to the event's directionality, allowing a significant improvement to the signal/background ratio in those physics channels. This is therefore one of the essential characteristics for the new generation of large neutrino detectors based on liquid scintillators, especially the Theia detector, one of the proposals for the fourth DUNE far detector module.This work plan is focused on two lines of development of the ARAPUCA technology and the evaluation of its feasibility:C-ARAPUCAs with high-pass filters instead of low-pass, for the detection of the Cherenkov light component with wavelengths above the typical scintillation region;ARAPUCA-QD using quantum dots for the wavelength-shifting plates of the ARAPUCAs dedicated to the high efficiency detection of scintillation light.The main experimental question to be answered are the measurement of the optical properties of the key-components - high-pass dichroic filters, scintillating plates with quantum dots - and of the performance of the corresponding prototype detectors in terms of efficiency and timing resolution. The direct comparison with existing detectors - C-ARAPUCA with low-pass filters and X-ARAPUCA with conventional wavelength shifters - will be part of the work plan. Monte Carlo simulation of the test setup will complement the measurements.Additionally this work plan intends to initiate a joint research activity between the visiting researcher and host institutes, of Monte Carlo simulations of the future hybrid detector in the sense of optimizing the configurations (size, number, geometrical placement) of the two subsystems C-ARAPUCA and ARAPUCA-QD. Being carried out at the Leptons laboratory of Unicamp, and integrated in the current project 2019/11557-2, this work plan will rely on excellent laboratorial conditions and the recognized experience of the host team.Dissemination activities will also be a priority at various levels - paper writing, communications at conferences and collaboration meetings, mini-course dedicated to PhD students. (AU)