Modeling of Heat Propagation Processes in Detection Pixel of Thermoelectric Single-Photon Detector with High-Temperature Superconducting Absorber

The processes of heat propagation in five-layer detection pixels of the thermoelectric single-photon detector after absorption of 0.8–1000 eV energy photons are investigated by the method of computer simulation. Design of the detection pixel consisting of successive layers on a sapphire substrate of heat sink Bi2223, thermoelectric sensor CeB₆, absorber Bi2223, and the antireflection layer SiO₂ is proposed. The computer modelling was carried out based on the equation of heat propagation from the limited volume by the use of the three-dimensional matrix method for differential equations. Temporal dependences of the signal intensity for different thicknesses of the layers of the detection pixel are determined. It is shown that the detection pixel SiO₂/Bi2223/CeB₆/Bi2223/Al₂O₃ can register single photons in a wide spectral range from near-IR to X-ray, as well as count the number of simultaneously absorbed photons up to eight. The use of Bi2223 high-temperature superconductor in the design of the detection pixel provides a gigahertz count rate and high system detection efficiency. The simple design of the detection pixel is a prerequisite for the creation of multi-pixel sensors. A detector with such characteristics could be representative of the next generation single-photon detectors in the near future.