An ambient-Temperature Continuously Rotating Half-Wave Plate (CRHWP) modulates the input polarization signal thereby enabling removal of low-frequency (1/f) noise from polarized flux measurements. This 1/f noise arises from atmospheric turbulence as well as from effects intrinsic to certain detectors. Here, we describe the design and performance of the half wave plate rotator and achromatic half-wave plate for the the new imaging polarimeter, TolTEC. These components are mounted in front of the cryostat window and operate at ambient temperature. The Half-Wave Plate Rotator (HWPR) spins the half-wave plate at 2 revolutions per second. The rotation mechanism consists of nine air bearings to provide low-friction motion and a frameless torque motor to directly drive rotation. The orientation of the rotor and half-wave plate are recorded using a high-precision optical encoder. We review the experimental requirements and technical design of the rotator as well as the associated electronics, pneumatics, and software.
The TolTEC camera: Polarimetric commissioning and performance of the continuously rotating half-wave plate / Lee, D.; Novak, G.; Berthoud, M.; Bussan, J.; Golenia, R.; Van Clepper, E.; Wilson, G.; Denigris, N. S.; Ma, Z.; Mccrackan, M.; Souccar, K.; Fissel, L.; Bij, A.; Thiel, F.; Aretxaga, I.; Ferrusca, D.; Mauskopf, P.; Lunde, E.; Ade, P.; Tucker, C.; Pisano, G.; Cox, E. G.; Sabin, L.; Carrasco-Gonzalez, C.; Pasetto, A.; Gomez-Ruiz, A.; Hull, C.; Austermann, J.; Beall, J.; Gao, J.; Vissers, M.. - 12190:(2022). (Intervento presentato al convegno Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI 2022 tenutosi a can) [10.1117/12.2627725].
The TolTEC camera: Polarimetric commissioning and performance of the continuously rotating half-wave plate
Pisano G.;
2022
Abstract
An ambient-Temperature Continuously Rotating Half-Wave Plate (CRHWP) modulates the input polarization signal thereby enabling removal of low-frequency (1/f) noise from polarized flux measurements. This 1/f noise arises from atmospheric turbulence as well as from effects intrinsic to certain detectors. Here, we describe the design and performance of the half wave plate rotator and achromatic half-wave plate for the the new imaging polarimeter, TolTEC. These components are mounted in front of the cryostat window and operate at ambient temperature. The Half-Wave Plate Rotator (HWPR) spins the half-wave plate at 2 revolutions per second. The rotation mechanism consists of nine air bearings to provide low-friction motion and a frameless torque motor to directly drive rotation. The orientation of the rotor and half-wave plate are recorded using a high-precision optical encoder. We review the experimental requirements and technical design of the rotator as well as the associated electronics, pneumatics, and software.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
