http://arxiv.org/abs/1403.1652
We describe the design, construction, and initial validation of the variable-delay polarization modulator (VPM) designed for the PIPER cosmic microwave background polarimeter. The VPM modulates between linear and circular polarization by introducing a phase delay between orthogonal linear polarizations. Each VPM has a diameter of 39 cm and is designed to operate in a cryogenic environment (1.5 K). We describe the mechanical design and performance of the kinematic double-blade flexure and drive mechanism along with the construction of the high precision wire grid polarizers.
D. Chuss, J. Eimer, D. Fixsen, et. al.
Mon, 10 Mar 14
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