Speaker
Description
Superconducting nano-wire single-photon detectors (SNSPDs) combine sub-eV sensitivity with intrinsic timing capabilities approaching the picosecond scale, making them compelling candidates for a new generation of high-energy physics detectors. Extending the exceptional single-photon performance of SNSPDs to relativistic charged particles enables high precision luminometry applications for future colliders, such as the Future Circular Collider (FCC), where a $10^{−4}$ precision level is envisaged.
In this presentation we investigate the interaction of charged particles with superconducting nano-wires using NbTiN, NbN and $MgB_{2}$ SNSPD devices. Detector performance is evaluated using laboratory $^{90}Sr$ source and 160 GeV pion beams at the CERN SPS within a EUDET-type MIMOSA-26 beam telescope providing ∼5 μm tracking resolution. Detection efficiency, spatial response, and timing characteristics of the devices are probed as a function of nano-wire geometry, bias conditions, and superconducting material properties.
To interpret microscopic detection mechanisms, measurements are complemented with a comprehensive simulation framework, linking charged-particle energy deposition to superconducting dynamics and electronic signal formation. Energy deposition is modeled within GEANT4 by implementing a custom extension of the Photo Absorption Ionization (PAI) model below the 10 eV Sandia tables limit using a Drude–Lorentz approximation. This approach explores the crucial low-energy excitation spectrum, relevant to the 800 meV effective threshold of tested geometries. The subsequent evolution of the superconducting condensate and transient resistive hot-spot formation are studied through time-dependent Ginzburg-Landau simulations, while SPICE-based circuit modeling generates expected pulse formation and readout behavior.
Together, these results provide direct insight into the coupling of ionizing radiation to superconducting nano-wires and establish the physical foundations for SNSPD-based charged-particle detectors with ultrafast timing capabilities. Ongoing production efforts and upcoming beam campaigns represent an important step toward fully superconducting tracking and luminometry systems for next-generation collider experiments.