Simulation-based design study for the passive shielding of the COSINUS dark matter experiment.

Area of Science:

• Experimental particle physics
• Astroparticle physics
• Dark matter detection

Background:

• Direct dark matter detection experiments aim to observe rare interactions between dark matter particles and ordinary matter.
• Sodium iodide (NaI) crystals are a target material used in dark matter searches, notably by the DAMA/LIBRA experiment.
• Distinguishing potential dark matter signals from background events is a significant challenge in low-background physics.

Purpose of the Study:

• To design and optimize the COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches) experiment for dark matter detection.
• To perform a detailed background budget estimation for the COSINUS facility.
• To minimize background particle interactions within the detector volume.

Main Methods:

• Utilizing scintillating cryogenic calorimeters with sodium iodide (NaI) crystals.
• Employing simultaneous detection of scintillation light and phonons for event-by-event signal discrimination.
• Conducting detailed Monte Carlo simulations to model background sources and optimize experimental geometry.
• Implementing a water tank as a cosmic ray veto and radiation shield.

Main Results:

• A comprehensive background budget estimation considering environmental and material radioactivity has been performed.
• Monte Carlo simulations have guided the optimization of the experimental setup's geometry.
• The final design aims to minimize residual background particles reaching the detector volume.
• The experimental facility design incorporates a cryostat with NaI crystals and shielding.

Conclusions:

• The COSINUS experiment is designed to probe dark matter signals using NaI crystals at cryogenic temperatures.
• Event-by-event discrimination using scintillation and phonon signals enhances sensitivity.
• Careful background estimation and simulation-driven design optimization are crucial for achieving high sensitivity in dark matter searches.
• The facility construction is planned to commence at the INFN Gran Sasso National Laboratory.