Speaker
Dr
Peter Ashton
(UC Berkeley / LBNL / Kavli IPMU)
Description
Located in the Atacama Desert of Chile, the Simons Observatory consists of one Large Aperture Telescope (LAT) and 3 Small Aperture Telescopes (SATs). The latter of these are optimized to observe the polarization in the CMB at large angular scales ( 30 < ℓ < 300), and as such we require a high degree of stability in our observations. To accomplish this we employ rapidly rotating sapphire cryogenic half wave plates (CHWPs) in the optical chain of the SATs. This design uses a 550 mm diameter superconducting magnetic bearing (SMB) for contactless rotation, the largest such bearing used in a telescope to date. In this talk I will discuss the design considerations and initial performance of the CHWP rotation mechanism.
