Speaker
Description
We introduce the FLASH experiment and present its electronic read-out system, currently under development. FLASH uses a resonant-cavity in a magnetic field to search for Dark Matter (DM) particles and High-Frequency Gravitational Waves (HFGWs). The cavity is operated at cryogenic temperatures to improve its performance, uses Superconducting Quantum Interference Devices (SQUIDs) as first-stage low-noise amplifiers and FPGA programmable logic coupled with ADCs and DACs to control the SQUIDs and acquire, preprocess and reduce the physics signal into a format suitable for permanent storage and offline analysis.
Summary (500 words)
The nature of Dark Matter (DM) is an open problem in fundamental physics, leading to current searches at high-energy and high-intensity colliders, fixed target experiments and low-energy ones. One of the candidates for DM is the axion, expected to be present in the universe as a continuous flux and capable of interacting with photons. The recent discovery of gravitational waves (GW) opened a new window into the observation of the universe and experiments are being developed in the search for GW in different frequency bands.
The FLASH experiment aims to develop and operate a resonant-cavity in the search for Dark Matter (DM) and High-Frequency Gravitational Waves (HFGW) in the 117 to 360 MHz band. The cavity operates below 4 K in a strong 1.1 T magnetic field, generated by the superconducting solenoid magnet of the former FINUDA particle physics experiment. The interaction of DM and HFGWs with the magnetic field is expected to produce electromagnetic excitations of the large (few cubic meters) cavity at an extremely low power level of 1E-22 Watts, thus requiring the use of a high quality factor (Q ~ 500’000) resonator - realized with pure copper operated at cryogenic temperatures, and an extremely low-noise first-stage amplifier - realized with a Microstrip SQUID Amplifier (MSA) - with a gain above 35 dB and a noise temperature of the order of 7 times the quantum limit. The high quality factor and resulting narrow passband (0.4-1.9 kHz) allows the cavity to be precisely tuned with movable rods embedded in the cavity. Following the MSA a cold amplifier is foreseen, feeding the signal digitizers and control electronics. The latter are implemented with an RF-capable FPGA system on a chip running embedded firmware, which is responsible for the digital signal processing.