The SMSPD under study
Left: The superconducting microwire single-photon detector, or SMSPD, is enclosed in a dark box to reduce background photons not from the beam. The detector is attached to the cold stage of the cryocooler, which keeps the temperature at very low temperatures, around 0.8 Kelvin. The beam enters through the hole in the center. Right: The SMSPD under study, represented by the small dark purple region. Credit: Christina Wang, Fermilab