Speaker
Description
The Project 8 collaboration aims to measure the absolute neutrino mass using Cyclotron Radiation Emission Spectroscopy (CRES). While early phases successfully demonstrated CRES at ~27 GHz using small-scale waveguide-based detectors, the experiment is transitioning to large-volume resonant cavities to achieve the necessary sensitivity and statistics. This design shift necessitates a strong reduction in operating frequency, starting with a 560 MHz demonstrator and ultimately moving to ~150 MHz for the final experiment. Detecting sub-femtowatt cyclotron signals at these frequencies requires a readout architecture operating near the Standard Quantum Limit (SQL), which is driving the development of custom superconducting technologies beyond the conventional C-band (4-8GHz).
We present the design, fabrication, and characterization of parametric amplifiers tailored to these unique frequency regimes. We report on Traveling Wave Parametric Amplifiers (TWPAs) fabricated at Lincoln Laboratories and MIT.Nano, showing gain performance in the 12–16 GHz band as well as the 600–900 MHz range necessary for the intermediate-scale cavity readout. Complementing these broadband devices, we show the development of narrowband Josephson Parametric Amplifiers (JPAs) led by the Colorado School of Mines. These designs include flux-pumped SQUID-based amplifiers fabricated at NIST, as well as novel non-linear dielectric capacitors utilizing Strontium Titanate (SrTiO3).
To validate these components and the system noise budget, we employ a compact low-frequency 2D superconducting resonator testbed at Mines. This setup allows for the injection of synthetic signals to verify gain profiles and investigate system noise contributions in a controlled environment.
Finally, we introduce a detection concept under development at the University of Washington that uses SQUIDs to detect the mirroring currents induced by the electron's axial motion. This technique provides kinematic information complementary to the primary CRES signal, offering a pathway to enhanced event reconstruction. These combined R&D efforts establish the foundation for the microwave readout needed to achieve the neutrino mass-sensitivity goals of Project 8.