A Large-Diameter Cryogenic Rotation Stage for Half-Wave Plate Polarization Modulation on the POLARBEAR-2 Experiment

We describe the design of a cryogenic rotation stage (CRS) for use with the cryogenic half-wave plate (CHWP) polarization modulator on the POLARBEAR-2b and POLARBEAR-2c (PB2b/c) cosmic microwave background (CMB) experiments, the second and third installments of the Simons Array. Rapid modulation of the CMB polarization signal using a CHWP suppresses 1/f contamination due to atmospheric turbulence and allows a single polarimeter to measure both polarization states, mitigating systematic effects that arise when differencing orthogonal detectors. To modulate the full detector array while avoiding excess photon loading due to thermal emission, the CHWP must have a clear-aperture diameter of > 450 mm and be cooled to < 100 K. We have designed a 454 mm clear-aperture, < 65 K CRS using a superconducting magnetic bearing driven by a synchronous magnetic motor. We present the specifications for the CRS, its interfacing to the PB2b/c receiver cryostat, its performance in a stand-alone test, and plans for future work.

[1]  N. Jarosik,et al.  Systematic effects from an ambient-temperature, continuously rotating half-wave plate. , 2016, The Review of scientific instruments.

[2]  J. Hull.  Effect of permanent-magnet irregularities in levitation force measurements , 1999 .

[3]  Britt Reichborn-Kjennerud,et al.  The performance of the bolometer array and readout system during the 2012/2013 flight of the E and B experiment (EBEX) , 2014, Astronomical Telescopes and Instrumentation.

[4]  U. Seljak,et al.  Signature of gravity waves in polarization of the microwave background , 1996, astro-ph/9609169.

[5]  S. Utsunomiya,et al.  Design and Performance of a Prototype Polarization Modulator Rotational System for Use in Space Using a Superconducting Magnetic Bearing , 2016, IEEE Transactions on Applied Superconductivity.

[6]  Peter Ade,et al.  The POLARBEAR experiment , 2012, Other Conferences.

[7]  P. Ade,et al.  The Simons Array CMB polarization experiment , 2016, Astronomical Telescopes + Instrumentation.

[8]  Matias Zaldarriaga,et al.  Direct signature of an evolving gravitational potential from the cosmic microwave background , 1999 .

[9]  G. P. Teply,et al.  POLARBEAR-2: an instrument for CMB polarization measurements , 2016, Astronomical Telescopes + Instrumentation.

[10]  Beck Wolfgang,et al.  遅延線陽極を持つMCP PMTに基づく広視野TCSPC FLIMシステム , 2016 .

[11]  Julian Borrill,et al.  Performance of a continuously rotating half-wave plate on the POLARBEAR telescope , 2017, 1702.07111.

[12]  Albert Stebbins,et al.  A Probe of Primordial Gravity Waves and Vorticity , 1997 .

[13]  Edward J. Wollack,et al.  Advanced ACTPol Cryogenic Detector Arrays and Readout , 2015, 1510.02809.

[14]  U. Seljak,et al.  An all sky analysis of polarization in the microwave background , 1996, astro-ph/9609170.

[15]  Brian Keating,et al.  Design and development of an ambient-temperature continuously-rotating achromatic half-wave plate for CMB polarization modulation on the POLARBEAR-2 experiment , 2016, Astronomical Telescopes + Instrumentation.

[16]  C. P. Bean,et al.  Magnetization of High-Field Superconductors , 1964 .

[17]  P. A. R. Ade,et al.  MAXIPOL: Cosmic Microwave Background Polarimetry Using a Rotating Half-Wave Plate , 2006, astro-ph/0611394.

[18]  Yuh-Jing Hwang,et al.  Strategies on solar observation of Atacama Large Millimeter/submillimeter Array (ALMA) band-1 receiver , 2016, Astronomical Telescopes + Instrumentation.

[19]  Peter Ade,et al.  A cryogenic rotation stage with a large clear aperture for the half-wave plates in the Spider instrument. , 2015, The Review of scientific instruments.

[20]  P. A. R. Ade,et al.  The POLARBEAR-2 and Simons Array Focal Plane Fabrication Status , 2018, Journal of Low Temperature Physics.

[21]  M. Zeisberger,et al.  Losses in magnetic bearings , 1998 .

[22]  Matias Zaldarriaga,et al.  Reconstructing projected matter density power spectrum from cosmic microwave background , 1999 .

[23]  B Smiley,et al.  A large-diameter hollow-shaft cryogenic motor based on a superconducting magnetic bearing for millimeter-wave polarimetry. , 2017, The Review of scientific instruments.

[24]  M. Nolta,et al.  Modulation of cosmic microwave background polarization with a warm rapidly rotating half-wave plate on the Atacama B-Mode Search instrument. , 2013, The Review of scientific instruments.