Quantum-based amplification and multiplexing for the Project 8 and Ricochet experiments

Readout of low-intensity microwave signals over a wide bandwidth has become increasingly important for fundamental science. The high frequency allows high information transfer, ideal for multiplexing detectors and reducing low-frequency noise.

This work presents the design and calibration of frequency-multiplexed readout for Ricochet, a segmented coherent neutrino scattering detector. The experimental goal to lower the recoil detection threshold requires unprecedented low-noise multiplexing.

Additionally, noise added by further microwave amplification is minimised by the use of Josephson Travelling Wave Parametric Amplifiers (JTWPAs), fulfilling the requirements of high-gain, high-bandwidth and single-photon noise. The integration of the multiplexer and JTWPA are presented in the 4-7GHz band, accompanied by ongoing R&D demonstrating JTWPA amplification around 25GHz.

Application of JTWPAs at the higher frequency ranges has the capability to lower the noise level by an order of magnitude compared to the traditional HEMT (High Electron Mobility Transistor) amplifiers. Single-photon noise levels open a window of the electromagnetic spectrum that the Project 8 direct neutrino mass experiment and other precision experiments will greatly benefit from.