BULLKID: Monolithic array of particle absorbers sensed by kinetic inductance detectors

We introduce BULLKID, a phonon detector consisting of an array dices acting as particle absorbers sensed by multiplexed Kinetic Inductance Detectors (KIDs). The are carved in thick crystalline wafer and form monolithic structure. carvings leave thin common disk intact the wafer, both holder for substrate KID lithography. prototype presented consists 64 5.4 × 5 mm3 3˝ diameter, mm silicon with 0.5 thick, hosting 60 nm patterned aluminum layer. resulting is highly segmented but avoids use dedicated holding structures each unit. Despite fact that uniformity electrical response across needs optimization, operation eight units similar features shows, on average, baseline energy resolution 26 ± 7 eV. This makes it suitable low-energy processes such direct interactions dark matter coherent elastic neutrino-nucleus scattering.