BICEP and the Keck Array use cryogenic telescopes with arrays of detectors sensitive to several frequencies of microwave radiation.
Notes on verification
Multiple independent peer-reviewed arxiv papers and the Caltech project page corroborate cryogenic design and multi-frequency detector arrays in detail. [tier=silver indep_score=1.0 clusters=2 claim_tier=notable]
Sources
- BICEP and Keck Array (wikipedia)
- https://arxiv.org/pdf/1502.00596 (corroboration)
- https://arxiv.org/pdf/1808.00569 (corroboration)
- https://cosmology.caltech.edu/projects/BICEP3 (corroboration)
- https://arxiv.org/pdf/1009.3685 (corroboration)