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Title: Performance of a continuously rotating half-wave plate on the POLARBEAR telescope

Abstract

A continuously rotating half-wave plate (CRHWP) is a promising tool to improve the sensitivity to large angular scales in cosmic microwave background (CMB) polarization measurements. With a CRHWP, single detectors can measure three of the Stokes parameters, I , Q and U , thereby avoiding the set of systematic errors that can be introduced by mismatches in the properties of orthogonal detector pairs. We focus on the implementation of CRHWPs in large aperture telescopes (i.e. the primary mirror is larger than the current maximum half-wave plate diameter of ∼0.5 m), where the CRHWP can be placed between the primary mirror and focal plane. In this configuration, one needs to address the intensity to polarization ( I → P ) leakage of the optics, which becomes a source of 1/f noise and also causes differential gain systematics that arise from CMB temperature fluctuations. In this paper, we present the performance of a CRHWP installed in the (\scshape Polarbear) experiment, which employs a Gregorian telescope with a 2.5 m primary illumination pattern. The CRHWP is placed near the prime focus between the primary and secondary mirrors. We find that the I → P leakage is larger than the expectation from the physicalmore » properties of our primary mirror, resulting in a 1/f knee of 100 mHz. The excess leakage could be due to imperfections in the detector system, i.e. detector non-linearity in the responsivity and time-constant. We demonstrate, however, that by subtracting the leakage correlated with the intensity signal, the 1/f noise knee frequency is reduced to 32 mHz (ℓ ∼ 39 for our scan strategy), which is very promising to probe the primordial B-mode signal. We also discuss methods for further noise subtraction in future projects where the precise temperature control of instrumental components and the leakage reduction will play a key role.« less

Authors:
 [1];  [2];  [3]; ; ;  [4];  [5]; ; ; ; ;  [6];  [7];  [8];  [9];  [10];  [11];  [12];  [13];
  1. Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043 Japan (Japan)
  2. Departamento de Física, FCFM, Universidad de Chile, Blanco Encalada 2008, Santiago (Chile)
  3. SOKENDAI (The Graduate University for Advanced Studies), Hayama, Miura District, Kanagawa, 240-0115 Japan (Japan)
  4. Department of Physics, University of California, San Diego, CA, 92093-0424 (United States)
  5. International School for Advanced Studies (SISSA), Via Bonomea 265, Trieste, I-34136 Italy (Italy)
  6. Department of Physics, University of California, Berkeley, CA, 94720 (United States)
  7. Centro de Astro-Ingeniería, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Santiago (Chile)
  8. Computational Cosmology Center, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 (United States)
  9. Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2 Canada (Canada)
  10. Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba, 277-8583 Japan (Japan)
  11. Sorbonne Universités, Institut Lagrange de Paris (ILP), 98 bis Boulevard Arago, Paris, 75014 France (France)
  12. Institut d'Astrophysique Spatiale, CNRS (UMR 8617), Université Paris-Sud, Université Paris-Saclay, bât. 121, Orsay, 91405 France (France)
  13. Yokohama National University, Yokohama, Kanagawa, 240-8501 Japan (Japan)
Publication Date:
OSTI Identifier:
22676231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2017; Journal Issue: 05; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APERTURES; CONFIGURATION; DEFECTS; FLUCTUATIONS; ILLUMINANCE; NOISE; PERFORMANCE; POLARIZATION; REDUCTION; RELICT RADIATION; SENSITIVITY; TELESCOPES; TEMPERATURE CONTROL

Citation Formats

Takakura, Satoru, Aguilar, Mario, Akiba, Yoshiki, Arnold, Kam, Elleflot, Tucker, Galitzki, Nicholas, Baccigalupi, Carlo, Barron, Darcy, Beckman, Shawn, Chinone, Yuji, Cukierman, Ari, Goeckner-Wald, Neil, Boettger, David, Borrill, Julian, Chapman, Scott, Ducout, Anne, Errard, Josquin, Fabbian, Giulio, Fujino, Takuro, E-mail: takakura@vega.ess.sci.osaka-u.ac.jp, and and others. Performance of a continuously rotating half-wave plate on the POLARBEAR telescope. United States: N. p., 2017. Web. doi:10.1088/1475-7516/2017/05/008.
Takakura, Satoru, Aguilar, Mario, Akiba, Yoshiki, Arnold, Kam, Elleflot, Tucker, Galitzki, Nicholas, Baccigalupi, Carlo, Barron, Darcy, Beckman, Shawn, Chinone, Yuji, Cukierman, Ari, Goeckner-Wald, Neil, Boettger, David, Borrill, Julian, Chapman, Scott, Ducout, Anne, Errard, Josquin, Fabbian, Giulio, Fujino, Takuro, E-mail: takakura@vega.ess.sci.osaka-u.ac.jp, & and others. Performance of a continuously rotating half-wave plate on the POLARBEAR telescope. United States. doi:10.1088/1475-7516/2017/05/008.
Takakura, Satoru, Aguilar, Mario, Akiba, Yoshiki, Arnold, Kam, Elleflot, Tucker, Galitzki, Nicholas, Baccigalupi, Carlo, Barron, Darcy, Beckman, Shawn, Chinone, Yuji, Cukierman, Ari, Goeckner-Wald, Neil, Boettger, David, Borrill, Julian, Chapman, Scott, Ducout, Anne, Errard, Josquin, Fabbian, Giulio, Fujino, Takuro, E-mail: takakura@vega.ess.sci.osaka-u.ac.jp, and and others. Mon . "Performance of a continuously rotating half-wave plate on the POLARBEAR telescope". United States. doi:10.1088/1475-7516/2017/05/008.
@article{osti_22676231,
title = {Performance of a continuously rotating half-wave plate on the POLARBEAR telescope},
author = {Takakura, Satoru and Aguilar, Mario and Akiba, Yoshiki and Arnold, Kam and Elleflot, Tucker and Galitzki, Nicholas and Baccigalupi, Carlo and Barron, Darcy and Beckman, Shawn and Chinone, Yuji and Cukierman, Ari and Goeckner-Wald, Neil and Boettger, David and Borrill, Julian and Chapman, Scott and Ducout, Anne and Errard, Josquin and Fabbian, Giulio and Fujino, Takuro, E-mail: takakura@vega.ess.sci.osaka-u.ac.jp and and others},
abstractNote = {A continuously rotating half-wave plate (CRHWP) is a promising tool to improve the sensitivity to large angular scales in cosmic microwave background (CMB) polarization measurements. With a CRHWP, single detectors can measure three of the Stokes parameters, I , Q and U , thereby avoiding the set of systematic errors that can be introduced by mismatches in the properties of orthogonal detector pairs. We focus on the implementation of CRHWPs in large aperture telescopes (i.e. the primary mirror is larger than the current maximum half-wave plate diameter of ∼0.5 m), where the CRHWP can be placed between the primary mirror and focal plane. In this configuration, one needs to address the intensity to polarization ( I → P ) leakage of the optics, which becomes a source of 1/f noise and also causes differential gain systematics that arise from CMB temperature fluctuations. In this paper, we present the performance of a CRHWP installed in the (\scshape Polarbear) experiment, which employs a Gregorian telescope with a 2.5 m primary illumination pattern. The CRHWP is placed near the prime focus between the primary and secondary mirrors. We find that the I → P leakage is larger than the expectation from the physical properties of our primary mirror, resulting in a 1/f knee of 100 mHz. The excess leakage could be due to imperfections in the detector system, i.e. detector non-linearity in the responsivity and time-constant. We demonstrate, however, that by subtracting the leakage correlated with the intensity signal, the 1/f noise knee frequency is reduced to 32 mHz (ℓ ∼ 39 for our scan strategy), which is very promising to probe the primordial B-mode signal. We also discuss methods for further noise subtraction in future projects where the precise temperature control of instrumental components and the leakage reduction will play a key role.},
doi = {10.1088/1475-7516/2017/05/008},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 05,
volume = 2017,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}
}
  • A continuously rotating half-wave plate (CRHWP) is a promising tool to improve the sensitivity to large angular scales in cosmic microwave background (CMB) polarization measurements. With a CRHWP, single detectors can measure three of the Stokes parameters, I, Q and U, thereby avoiding the set of systematic errors that can be introduced by mismatches in the properties of orthogonal detector pairs. We focus on the implementation of CRHWPs in large aperture telescopes (i.e. the primary mirror is larger than the current maximum half-wave plate diameter of ~0.5 m), where the CRHWP can be placed between the primary mirror and focalmore » plane. In this configuration, one needs to address the intensity to polarization (I→P) leakage of the optics, which becomes a source of 1/f noise and also causes differential gain systematics that arise from CMB temperature fluctuations. In this paper, we present the performance of a CRHWP installed in the {\scshape Polarbear} experiment, which employs a Gregorian telescope with a 2.5 m primary illumination pattern. The CRHWP is placed near the prime focus between the primary and secondary mirrors. We find that the I→P leakage is larger than the expectation from the physical properties of our primary mirror, resulting in a 1/f knee of 100 mHz. The excess leakage could be due to imperfections in the detector system, i.e. detector non-linearity in the responsivity and time-constant. We demonstrate, however, that by subtracting the leakage correlated with the intensity signal, the 1/f noise knee frequency is reduced to 32 mHz (ℓ ~ 39 for our scan strategy), which is very promising to probe the primordial B-mode signal. We also discuss methods for further noise subtraction in future projects where the precise temperature control of instrumental components and the leakage reduction will play a key role.« less
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  • Flood-point data have been determined for six solventwater systems using a 3 in. diameter pulsed plate-column. The variables investigated were the plate spacing, plate geometry (i.e. hole-size and percentage free area), and the pulse wave-form. In the latter case, sinusoidal, saw-tooth, and semi-square wave-forms were selected for study. In the absence of an undistributed solute, the data were interpreted in terms of the characteristic velocity which was correlated with the column variables, the physical properties of the system and the pulse characteristics. Mass transfer data were obtained for both directions of transfer using the systems water-toluene and water --butyl acetatemore » with acetone as solute. Overall (H.T.U.) values for a given system were correlated in terms of variations in the interfacial area. (auth)« less
  • Results of an experimental study of a counter-rotating turbine operating on a pneumatic wave energy conversion system are presented. The vertical capture chamber of the water column of the system has a down-facing water intake. An electrical generator (d-c) is coupled to the turbine by a ten-gear-ratio drive train. Tests of the pneumatic wave energy conversion system were conducted with the mouth at two depths in order to vary the natural oscillating frequency of the water column. The maximum electrical power output of the system was approximately 90 W in the monochromatic waves. This value corresponds to at 36-percent efficiencymore » based on the incident wave power in a wave crest width equal to the diameter of the capture chamber. The theoretical maximum efficiency of such a system has been shown to be 50 percent by several investigators.« less