FIG. 2.

(a) Schematic of cryotron switch and operation. An AlMn signal line is switched from superconducting to normal via the magnetic fields ($\overrightarrow{B}$) generated by current at the edges of the winding Nb control line.¹⁵ (b) Detailed view of the cryotron with the superconducting transformers in a dipole gradiometer orientation. (c) The first 2 channels of a 32-channel “interface chip” (IF). In our implementation of CDM, the TES shunt resistors ($R_{\text{sh}}$) and bandwidth-limiting inductors ($L_{\text{ny}}$) for a readout column are deposited on the IF. The cryotron signal line is in series with TES 1, while the “control” bond pads are used to activate the cryotron.