Speaker
Description
BULLKID-DM is a cryogenic experiment designed for the direct detection of WIMP-like dark matter particles with mass of 1 GeV or below. The detector will consist of a stack of 16 intrinsic silicon wafers, for a total mass of 800 g, carved into 2320 active dice each with a volume of 5.4×5.4×5 mm3. The silicon dice will be instrumented with multiplexed phonon-mediated Kinetic Inductance Detectors (KIDs), acting as particle absorbers with an individual energy threshold of 200 eV or better. This design results in a fully monolithic yet highly segmented structure, with volume fiducialization capabilities to improve background discrimination. The detector will be operated in a dry dilution refrigerator at the Gran Sasso underground laboratory (LNGS).
To minimize the environmental background, besides the use of radiopure materials, a comprehensive shield system will be implemented, consisting of a mixture of lead, copper and neutron moderator material (B4C) placed both inside and outside the cryostat. A cryogenic anti-coincidence veto system, using scintillating crystals with KIDs readout, is also designed to further suppress the external gamma backgrounds.
A 60 g demonstrator with 180 dice is being tested in a surface laboratory with a lead and copper radiation shield, and it is intended to be validated at LNGS by late 2026. The full experiment is expected to be commissioned in 2027. This presentation will show the milestones achieved so far and the future plans of BULLKID-DM.