Quasiparticle diffusion, edge losses, and back-tunneling in superconducting tunnel junctions under x-ray irradiation

Research was conducted to examine the loss of quasiparticles, both in the bulk and at the edges of the electrodes of superconducting tunnel junctions. The amount of charge carriers tunneling was restricted by the quasiparticle loss that occurs during their diffusion in the junction. A comparison of theoretical predictions with an experimental pulse height spectrum derived on a Nb/Al2O3/Nb junction was performed.