The 20th International Conference on Low Temperature Detectors (LTD20)
Presentation Code : T-2-5
Presentation Schedule: : July 25, 11:50 ~ 12:05

Performance of a Phonon-Mediated MKID Device at the NEXUS Low-Background Facility

Dylan Temples1, Lauren Hsu1, Osmond Wen2, Karthik Ramanathan2, Sunil Golwala2, Noah Kurinsky3, Hannah Magoon4
1Fermi National Accelerator Laboratory, United States of America, 2California Institute of Technology, United States of America, 3SLAC National Accelerator Laboratory, United States of America, 4Tufts University, United States of America

Phonon-mediated Microwave Kinetic Inductance Detectors (MKIDs) offer an attractive architecture for novel microcalorimeters to probe dark matter (DM) down to the fermionic thermal relic mass limit of a few keV. A phonon-sensitive MKID device featuring an aluminum resonator patterned onto a silicon substrate has been operating at the NEXUS low-background facility at Fermilab for characterization and evaluation of its efficacy for a dark matter search. With this device we have demonstrated a resolution on energy deposited in the substrate of 320 eV, limited by the <1% phonon collection efficiency. However, with this measurement we have demonstrated a resolution on the energy absorbed by the superconductor of 2.5 eV, a factor of two better than the current state-of-the-art, enabled by ~ms quasiparticle lifetimes. In this talk, I will present our measurement of the energy resolution and phonon collection efficiency performed by exposing the bare substrate to a pulsed source of 470 nm photons. I will also discuss our investigations into quasiparticle lifetimes within the superconducting resonator and review the current status and next steps of the phonon-mediated MKIDs for DM effort at Fermilab.

• Presentation Preference : Oral
• Topic : A. Detector Physics & Technologies
- 02. KID
• Corresponding Author : Dylan Temples (Fermilab)
• Presenter : Dylan Temples (Fermilab)