Towards a Low-Cost Readout System for Arrays of Cryogenic Detectors

A microwave kinetic inductance detector (MKID) is a superconducting pair-breaking detector used for astronomical observations in the sub-millimeter through visible range. Radiation is detected as a phase and amplitude signal proportional to the frequency shift of the device. In the case of arrays of MKIDs, the read-out is performed using the frequency division multiplexing technique. However, there is currently no commercial system or low-cost standard electronics available for this task. In this work, we take the first steps towards developing a low-cost readout system for MKIDs based on the Red Pitaya board. We have developed a firmware for the efficient generation of probe tones, and show figures of merit characterizing the performance of the readout in a hardware prototype. The design is flexible, letting us to adapt it to new frequencies and amplitudes requirements of the MKID arrays.