Abstract
We describe an on-sky demonstration of a microwave-multiplexing readout system in one of the receivers of the Keck Array, a polarimetry experiment observing the cosmic microwave background at the South Pole. During the austral summer of 2018–2019, we replaced the time-division multiplexing readout system with microwave-multiplexing components including superconducting microwave resonators coupled to radio frequency superconducting quantum interference devices at the sub-Kelvin focal plane, coaxial-cable plumbing and amplification between room temperature and the cold stages, and a SLAC Microresonator Radio Frequency system for the warm electronics. In the range 5–6 GHz, a single coaxial cable reads out 528 channels. The readout system is coupled to transition-edge sensors, which are in turn coupled to 150-GHz slot-dipole phased-array antennas. Observations began in April 2019, and we report here on an initial characterization of the system performance.
| Original language | English |
|---|---|
| Pages (from-to) | 858-866 |
| Number of pages | 9 |
| Journal | Journal of Low Temperature Physics |
| Volume | 199 |
| Issue number | 3-4 |
| DOIs | |
| State | Published - May 1 2020 |
| Externally published | Yes |
Keywords
- BICEP
- CMB
- Keck Array
- Microwave multiplexing
- SMuRF
- Tone tracking