• Fernandez, F. Vazquez De Sola
• Corcoran, E. C.
• Giroux, G.
• Manthos, I.
• Savvidis, G.
• Santos, D.
• Mccabe, Christopher
• Guillaudin, O.
• Hamaide, L.
• Neep, T.
• Gros, M.
• Matthews, J.
• Rowe, N.
• Katsioulas, I.
• Mimasu, K.
• Beaufort, C.
• Chapellier, M.
• Giomataris, I.
• Dastgheibi-Fard, A.
• Durnford, D.
• Gerbier, G.
• Obrien, P.
• Paling, S.
• Balogh, L.
• Martin, R. D.
• Kelly, F.
• Savvidis, I.
• Lautridou, P.
• Ward, R.
• Nikolopoulos, K.
• Banks, E.
• Gros, P.
• Gorel, P.
• Muraz, J.-F.
• Piro, M.-C.
• Hoppe, E. W.
• Coquillat, J.-M.
• Knights, P.
• Garrah, C.
• Deng, Y.

Abstract

We present the conceptual design and the physics potential of DarkSphere, a proposed 3m in diameter spherical proportional counter electroformed underground at the Boulby Underground Laboratory. This effort builds on the R&D performed and experience acquired by the NEWS-G Collaboration. DarkSphere is primarily designed to search for nuclear recoils from light dark matter in the 0.05–10 GeV mass range. Electroforming the spherical shell and the implementation of a shield based on pure water ensures a background level below 0.01 dru. These, combined with the proposed helium-isobutane gas mixture, will provide sensitivity to the spin-independent nucleon cross section of 2×10⁻⁴¹ (2×10⁻⁴³) cm² for a dark matter mass of 0.1(1) GeV. The use of a hydrogen-rich gas mixture with a natural abundance of ¹³C provides sensitivity to spin-dependent nucleon cross sections more than two orders of magnitude below existing constraints for dark matter lighter than 1 GeV. The characteristics of the detector also make it suitable for searches of other dark matter signatures, including scattering of MeV-scale dark matter with electrons, and superheavy dark matter with masses around the Planck scale that leave extended ionization tracks in the detector.

Topics

• impedance spectroscopy
• Hydrogen