Particle Detection Using MKID-Based Athermal-Phonon Mediated Detectors

Abstract

We are developing athermal-phonon mediated particle detectors that utilize microwave kinetic inductance detectors (MKIDs) as phonon sensors. MKIDs afford natural frequency domain multiplexing, which allows for massive substrates to be patterned with hundreds of sensors while keeping readout complexity to a minimum. Previously, our 2 cm × 2 cm × 1 mm proof-of-principle device utilized 20 MKIDs and, from the magnitude and timing of their response, we were able to reconstruct the position of a particle interaction to < 1 mm. From this, we corrected for variations in detector response across the device and measured an energy resolution of σ_E = 0.55 keV at 30 keV. We have designed and fabricated a new 3-inch prototype device that utilizes 256 MKID sensors, and we present results from its initial testing. Applications include rare event searches, such as the direct detection of dark matter and neutrinoless double beta decay, as well as hard X-ray/soft γ-ray astrophysics.