Speaker
Description
We operate two cryogenic quartz bulk-acoustic-wave (BAW) strain antennas of the Multi-mode Acoustic Gravitational-wave Experiment (MAGE) simultaneously in a single dilution refrigerator, one at millikelvin temperatures and the other at 1 K. Each is read by an independent SQUID amplifier chain, and both are digitised by a common radio-frequency system-on-chip (RFSoC) lock-in providing 64 simultaneous demodulation channels per chain.
Acquisition is disciplined by a GPS-referenced 10 MHz standard and a 1 PPS signal, giving absolute UTC timing. Over six weeks of operation, we resolve 54 acoustic modes on the 1 K antenna and 14 at millikelvin, spanning 4.99–15.73 MHz. Both antennas are searched for transient energy deposits using a matched filter templated on the free ring-down of each mode. This work is in preparation for GravNet, a global detector network to search for high-frequency gravitational waves. To that end, we are coordinating with the BAUSCIA experiment in Milan, operating near-identical crystals simultaneously and monitoring the same acoustic modes, with the aim of extending this two-detector coincidence to an intercontinental baseline.
The detector is also sensitive to various forms of dark matter that cause oscillations in fundamental constants, which is a line of future research.