High-Throughput, DC-Parametric Evaluation of Flux-Activated-Switch-Based TDM and CDM SQUID Multiplexers

The successful realization and broad deployment of transition edge sensor (TES)-based detector systems has led to significant demand for time-division and code-division superconducting quantum interference device (SQUID) multiplexers time division multiplexing (TDM) and code division multiplexing (CDM) as essential components of the cryogenic readout chain. TDM and CDM circuits are produced by the Boulder Microfabrication Facility in large quantities and in multiple varieties to meet the needs of various bolometric and calorimetric applications. In most cases, the basic functionality of these devices must be verified before they are passed along to internal or external collaborators for integration into scientific instruments. We have developed a test bed that utilizes the NIST TDM/CDM read-out electronics to make automated multiplexed measurements on sixteen devices simultaneously in a 4 K liquid-helium dip probe. The optimization of the measurement process has resulted in vastly improved throughput and enhanced data products. We present a thorough analysis of results from the application of the test process to flux-activated-switch-style multiplexers. The utility of this approach in identifying fabrication trends, yield indicators, and common failure modes will be demonstrated.