Speaker
Maria Simanovskaia
(University of California, Berkeley)
Description
Axions are a leading dark matter candidate, and may be detected by their resonant conversion to a monochromatic RF signal in a tunable microwave cavity permeated by a strong magnetic field. The Axion Dark Matter eXperiment – High Frequency (ADMX-HF) serves both as a innovation platform for cavity and amplifier technologies for the microwave cavity axion experiment, and as a pathfinder for a first look at data in the 20 – 100 μeV (~ 4 – 25 GHz) range. A collaboration of Yale University, where the experiment is sited, the University of California Berkeley, Colorado University, and Lawrence Livermore National Laboratory, ADMX-HF is a small but highly capable platform where advanced concepts can be developed and vetted in an operational environment. The experiment is built on a superconducting solenoidal magnet (9 T, 17.5 cm ∅ x 40 cm) of high field uniformity, and a dilution refrigerator capable of cooling the cavity and amplifier to 25 mK. In its initial configuration, the microwave cavity is made of high purity electroformed copper, tunable between 3.6 – 5.8 GHz. The cavity is coupled to a Josephson Parametric Amplifier; JPAs are ideally suited for the 5 GHz range, being broadly tunable and exhibiting near-quantum-limited noise temperature. Construction of the experiment was completed in 2015, and has embarked on a first data run in January 2016. Technologies to be deployed in the near future include a squeezed-vacuum state receiver, superconducting thin-film cavities, and photonic band-gap resonators. This work was supported under the auspices of the National Science Foundation, under grants PHY-1067242 and PHY-1306729, the Heising-Simons Foundation under grant 2014-182, and the U.S. Department of Energy by Lawrence Livermore National Security, LLC, Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
