Cryogenic sensors composed of transition-biased superconducting films have demonstrated remarkable sensitivity at gamma-ray, x-ray, optical, and submillimeter wavelengths. However, for these sensors to find widespread application in astronomy and materials analysis, technologies for building and reading-out large arrays are required. We are currently developing a frequency-domain multiplexing scheme for the read-out of large numbers of microcalorimeters using a much smaller number of amplifiers. In this scheme, each sensor is biased at an identifying frequency and operated in a series LC circuit to suppress out-of-band noise. Here, we present results demonstrating the undegraded operation of two gamma-ray sensors multiplexed using this technique. In addition, we provide a series of design rules which relate the minimum bias frequency and the values of the reactive elements in the system to a small number of sensor properties. Finally, we discuss the ultimate limits on the number of sensors that can be measured with a single amplifier.
Citation: IEEE Transactions on Applied Superconductivity
Pub Type: Journals
microcalorimeters, multiplexing, SQUIDs, transition-edge sensors