-
S. Moyerman,
E. Bierman,
P. A. R. Ade,
R. Aiken,
D. Barkats,
C. Bischoff,
J. J. Bock,
H. C. Chiang,
C. D. Dowell,
L. Duband, [......],
H. T. Nguyen,
N. Ponthieu,
C. Pryke,
S. Richter,
G. Rocha,
C. Sheehy,
Y. D. Takahashi,
J. E. Tolan,
E. Wollack, K. W. Yoon
[show abstract]
[hide abstract]
ABSTRACT: The design and performance of a wide bandwidth linear polarization modulator
based on the Faraday effect is described. Faraday Rotation Modulators (FRMs)
are solid-state polarization switches that are capable of modulation up to ~10
kHz. Six FRMs were utilized during the 2006 observing season in the Background
Imaging of Cosmic Extragalactic Polarization (BICEP) experiment; three FRMs
were used at each of BICEP's 100 and 150 GHz frequency bands. The technology
was verified through high signal-to-noise detection of Galactic polarization
using two of the six FRMs during four observing runs in 2006. The features
exhibit strong agreement with BICEP's measurements of the Galaxy using non-FRM
pixels and with the Galactic polarization models. This marks the first
detection of high signal-to-noise mm-wave celestial polarization using fast,
active optical modulation. The performance of the FRMs during periods when they
were not modulated was also analyzed and compared to results from BICEP's 43
pixels without FRMs.
12/2012;
-
K. Story,
E. Leitch,
P. Ade,
K. A. Aird,
J. E. Austermann,
J. A. Beall,
D. Becker,
A. N. Bender,
B. A. Benson,
L. E. Bleem, [......],
G. Smecher,
B. Stalder,
C. Tucker,
K. Vanderlinde,
J. D. Vieira,
G. Wang,
R. Williamson,
V. Yefremenko, K. W. Yoon,
E. Young
[show abstract]
[hide abstract]
ABSTRACT: We present the software system used to control and operate the South Pole
Telescope. The South Pole Telescope is a 10-meter millimeter-wavelength
telescope designed to measure anisotropies in the cosmic microwave background
(CMB) at arcminute angular resolution. In the austral summer of 2011/12, the
SPT was equipped with a new polarization-sensitive camera, which consists of
1536 transition-edge sensor bolometers. The bolometers are read out using 36
independent digital frequency multiplexing (\dfmux) readout boards, each with
its own embedded processors. These autonomous boards control and read out data
from the focal plane with on-board software and firmware. An overall control
software system running on a separate control computer controls the \dfmux
boards, the cryostat and all other aspects of telescope operation. This control
software collects and monitors data in real-time, and stores the data to disk
for transfer to the United States for analysis.
10/2012;
-
J. T. Sayre,
P. Ade,
K. A. Aird,
J. E. Austermann,
J. A. Beall,
D. Becker,
B. A. Benson,
L. E. Bleem,
J. Britton,
J. E. Carlstrom, [......],
E. Shirokoff,
K. Story,
C. Tucker,
K. Vanderlinde,
J. D. Vieira,
G. Wang,
R. Williamson,
V. Yefremenko, K. W. Yoon,
E. Young
[show abstract]
[hide abstract]
ABSTRACT: The SPTpol camera is a two-color, polarization-sensitive bolometer receiver,
and was installed on the 10 meter South Pole Telescope in January 2012. SPTpol
is designed to study the faint polarization signals in the Cosmic Microwave
Background, with two primary scientific goals. One is to constrain the
tensor-to-scalar ratio of perturbations in the primordial plasma, and thus
constrain the space of permissible inflationary models. The other is to measure
the weak lensing effect of large-scale structure on CMB polarization, which can
be used to constrain the sum of neutrino masses as well as other growth-related
parameters. The SPTpol focal plane consists of seven 84-element monolithic
arrays of 150 GHz pixels (588 total) and 180 individual 90 GHz single-pixel
modules. In this paper we present the design and characterization of the 90 GHz
modules.
10/2012;
-
J. W. Henning,
P. Ade,
K. A. Aird,
J. E. Austermann,
J. A. Beall,
D. Becker,
B. A. Benson,
L. E. Bleem,
J. Britton,
J. E. Carlstrom, [......],
E. Shirokoff,
K. Story,
C. Tucker,
K. Vanderlinde,
J. D. Vieira,
G. Wang,
R. Williamson,
V. Yefremenko, K. W. Yoon,
E. Young
[show abstract]
[hide abstract]
ABSTRACT: The SPTpol camera is a dichroic polarimetric receiver at 90 and 150 GHz.
Deployed in January 2012 on the South Pole Telescope (SPT), SPTpol is looking
for faint polarization signals in the Cosmic Microwave Background (CMB). The
camera consists of 180 individual Transition Edge Sensor (TES) polarimeters at
90 GHz and seven 84-polarimeter camera modules (a total of 588 polarimeters) at
150 GHz. We present the design, dark characterization, and in-lab optical
properties of the 150 GHz camera modules. The modules consist of
photolithographed arrays of TES polarimeters coupled to silicon platelet arrays
of corrugated feedhorns, both of which are fabricated at NIST-Boulder. In
addition to mounting hardware and RF shielding, each module also contains a set
of passive readout electronics for digital frequency-domain multiplexing. A
single module, therefore, is fully functional as a miniature focal plane and
can be tested independently. Across the modules tested before deployment, the
detectors average a critical temperature of 478 mK, normal resistance R_N of
1.2 Ohm, unloaded saturation power of 22.5 pW, (detector-only) optical
efficiency of ~ 90%, and have electrothermal time constants < 1 ms in
transition.
10/2012;
-
J. E. Austermann,
K. A. Aird,
J. A. Beall,
D. Becker,
A. Bender,
B. A. Benson,
L. E. Bleem,
J. Britton,
J. E. Carlstrom,
C. L. Chang, [......],
E. Shirokoff,
A. A. Stark,
K. Story,
K. Vanderlinde,
J. D. Vieira,
G. Wang,
R. Williamson,
V. Yefremenko, K. W. Yoon,
O. Zahn
[show abstract]
[hide abstract]
ABSTRACT: SPTpol is a dual-frequency polarization-sensitive camera that was deployed on
the 10-meter South Pole Telescope in January 2012. SPTpol will measure the
polarization anisotropy of the cosmic microwave background (CMB) on angular
scales spanning an arcminute to several degrees. The polarization sensitivity
of SPTpol will enable a detection of the CMB "B-mode" polarization from the
detection of the gravitational lensing of the CMB by large scale structure, and
a detection or improved upper limit on a primordial signal due to inflationary
gravity waves. The two measurements can be used to constrain the sum of the
neutrino masses and the energy scale of inflation. These science goals can be
achieved through the polarization sensitivity of the SPTpol camera and careful
control of systematics. The SPTpol camera consists of 768 pixels, each
containing two transition-edge sensor (TES) bolometers coupled to orthogonal
polarizations, and a total of 1536 bolometers. The pixels are sensitive to
light in one of two frequency bands centered at 90 and 150 GHz, with 180 pixels
at 90 GHz and 588 pixels at 150 GHz. The SPTpol design has several features
designed to control polarization systematics, including: single-moded feedhorns
with low cross-polarization, bolometer pairs well-matched to difference
atmospheric signals, an improved ground shield design based on far-sidelobe
measurements of the SPT, and a small beam to reduce temperature to polarization
leakage. We present an overview of the SPTpol instrument design, project
status, and science projections.
10/2012;
-
E. M. George,
P. Ade,
K. A. Aird,
J. E. Austermann,
J. A. Beall,
D. Becker,
A. Bender,
B. A. Benson,
L. E. Bleem,
J. Britton, [......],
E. Shirokoff,
K. Story,
C. Tucker,
K. Vanderlinde,
J. D. Vieira,
G. Wang,
R. Williamson,
V. Yefremenko, K. W. Yoon,
E. Young
[show abstract]
[hide abstract]
ABSTRACT: In January 2012, the 10m South Pole Telescope (SPT) was equipped with a
polarization-sensitive camera, SPTpol, in order to measure the polarization
anisotropy of the cosmic microwave background (CMB). Measurements of the
polarization of the CMB at small angular scales (~several arcminutes) can
detect the gravitational lensing of the CMB by large scale structure and
constrain the sum of the neutrino masses. At large angular scales (~few
degrees) CMB measurements can constrain the energy scale of Inflation. SPTpol
is a two-color mm-wave camera that consists of 180 polarimeters at 90 GHz and
588 polarimeters at 150 GHz, with each polarimeter consisting of a dual
transition edge sensor (TES) bolometers. The full complement of 150 GHz
detectors consists of 7 arrays of 84 ortho-mode transducers (OMTs) that are
stripline coupled to two TES detectors per OMT, developed by the TRUCE
collaboration and fabricated at NIST. Each 90 GHz pixel consists of two
antenna-coupled absorbers coupled to two TES detectors, developed with Argonne
National Labs. The 1536 total detectors are read out with digital
frequency-domain multiplexing (DfMUX). The SPTpol deployment represents the
first on-sky tests of both of these detector technologies, and is one of the
first deployed instruments using DfMUX readout technology. We present the
details of the design, commissioning, deployment, on-sky optical
characterization and detector performance of the complete SPTpol focal plane.
10/2012;
-
R. O'Brient,
P. A. R. Ade,
Z. Ahmed,
R. W. Aikin,
M. Amiri,
S. Benton,
C. Bischoff,
J. J. Bock,
J. A. Bonetti,
J. A. Brevik, [......],
G. Teply,
J. E. Tolan,
A. D. Turner,
R. S. Tucker,
A. Vieregg,
D. V. Wiebe,
P. Wilson,
C. L. Wong,
W. L. K. Wu, K. W. Yoon
[show abstract]
[hide abstract]
ABSTRACT: Between the BICEP2 and Keck Array experiments, we have deployed over 1500
dual polarized antenna coupled bolometers to map the Cosmic Microwave
Background's polarization. We have been able to rapidly deploy these detectors
because they are completely planar with an integrated phased-array antenna.
Through our experience in these experiments, we have learned of several
challenges with this technology- specifically the beam synthesis in the
antenna- and in this paper we report on how we have modified our designs to
mitigate these challenges. In particular, we discus differential steering
errors between the polarization pairs' beam centroids due to microstrip cross
talk and gradients of penetration depth in the niobium thin films of our
millimeter wave circuits. We also discuss how we have suppressed side lobe
response with a Gaussian taper of our antenna illumination pattern. These
improvements will be used in Spider, Polar-1, and this season's retrofit of
Keck Array.
08/2012;
-
J. Hubmayr,
J.E. Austermann,
J.A. Beall,
D. Becker,
D.A. Bennett,
B.A. Benson,
L.E. Bleem,
C.L. Chang,
J.E. Carlstrom,
H. Cho, [......],
J. McMahon,
J. Mehl,
S.S. Meyer,
J.P. Nibarger,
M.D. Niemack,
D.R. Schmidt,
E. Shirokoff,
S.M. Simon, K.W. Yoon,
E.Y. Young
[show abstract]
[hide abstract]
ABSTRACT: We are developing arrays of 150 GHz transition edge sensor (TES) polarimeters for the South Pole Telescope polarimeter (SPTpol). Prototype devices use an aluminum manganese (Al-Mn) alloy TES with a normal resistance R<sub>n</sub> suited to frequency domain multiplexing (fMUX) used in SPTpol. Using the fMUX readout, the devices exhibit noise performance consistent with expectations when R >; 0.8R<sub>n</sub>. Below 0.8R<sub>n</sub>, the detectors have high loopgain and become unstable, which is predicted by use of a compound TES model. We address this issue in a recent fabrication with increased TES heat capacity and normal metal structures on the TES to tune the temperature sensitivity.
IEEE Transactions on Appiled Superconductivity 07/2011; · 1.04 Impact Factor
-
D.R. Schmidt,
H.-M. Cho,
J. Hubmayr,
P. Lowell,
M.D. Niemack,
G.C. O'Neil,
J.N. Ullom, K.W. Yoon,
K.D. Irwin,
W.L. Holzapfel,
M. Lueker,
E.M. George,
E. Shirokoff
[show abstract]
[hide abstract]
ABSTRACT: Superconducting transition edge sensors (TES) require superconducting films with transition temperatures (T<sub>c</sub>) and properties that can be tailored to the particular requirements of individual applications. We have been developing Al-Mn films with a tunable T<sub>c</sub>. The addition of Mn to Al suppresses T<sub>c</sub>, but does not significantly broaden the superconducting density of states of the Al. We can produce films with T<sub>c</sub> from below 50 mK to 1.4 K through adjustment of the Mn concentration. Since this is a bulk effect, T<sub>c</sub> is not as dependent on precise control of film thickness as in the standard bilayer approach for TESs. We have previously used Al-Mn to fabricate TES sensors for x-ray microcalorimeters targeted for read-out with time division SQUID multiplexing schemes. In this work, we explore the properties of Al-Mn in a regime well suited for frequency division multiplexing. We have also fabricated prototype Al-Mn cosmic microwave background polarimeters for the South Pole Telescope and will show initial measurements of these sensors.
IEEE Transactions on Appiled Superconductivity 07/2011; · 1.04 Impact Factor
-
T. Essinger-Hileman,
J. W. Appel,
J.A. Beall,
H. M. Cho,
J. Fowler,
M. Halpern,
M. Hasselfield,
K. D. Irwin,
T. A. Marriage,
M. D. Niemack,
L. Page,
L. P. Parker,
S. Pufu,
S. T. Staggs,
O. Stryzak,
C. Visnjic, K. W. Yoon,
Y Zhao
[show abstract]
[hide abstract]
ABSTRACT: The Atacama B-mode Search (ABS) experiment is a 145 GHz polarimeter designed to measure the B-mode polarization of the Cosmic Microwave Background (CMB) at large angular scales. The ABS instrument will ship to the Atacama Desert of Chile fully tested and ready to observe in 2010. ABS will image large-angular-scale CMB polarization anisotropies onto a focal plane of 240 feedhorn-coupled, transition-edge sensor (TES) polarimeters, using a cryogenic crossed-Dragone design. The ABS detectors, which are fabricated at NIST, use orthomode transducers to couple orthogonal polarizations of incoming radiation onto separate TES bolometers. The incoming radiation is modulated by an ambient-temperature half-wave plate in front of the vacuum window at an aperture stop. Preliminary detector characterization indicates that the ABS detectors can achieve a sensitivity of 300 $\mu K \sqrt{s}$ in the field. This paper describes the ABS optical design and detector readout scheme, including feedhorn design and performance, magnetic shielding, focal plane architecture, and cryogenic electronics. Comment: 4 pages, 5 figures, Proceedings of the Thirteenth International Conference on Low-Temperature Detectors
08/2010;
-
M. D. Niemack,
P. A. R. Ade,
J. Aguirre,
F. Barrientos,
J.A. Beall,
J. R. Bond,
J. Britton,
H. M. Cho,
S Das,
M. J. Devlin, [......],
L. A. Page,
B. Partridge,
E. D. Reese,
J. Sievers,
D. N. Spergel,
S. T. Staggs,
R. Thornton,
C. Tucker,
E. Wollack, K. W. Yoon
[show abstract]
[hide abstract]
ABSTRACT: The six-meter Atacama Cosmology Telescope (ACT) in Chile was built to measure the cosmic microwave background (CMB) at arcminute angular scales. We are building a new polarization sensitive receiver for ACT (ACTPol). ACTPol will characterize the gravitational lensing of the CMB and aims to constrain the sum of the neutrino masses with ~0.05 eV precision, the running of the spectral index of inflation-induced fluctuations, and the primordial helium abundance to better than 1%. Our observing fields will overlap with the SDSS BOSS survey at optical wavelengths, enabling a variety of cross-correlation science, including studies of the growth of cosmic structure from Sunyaev-Zel'dovich observations of clusters of galaxies as well as independent constraints on the sum of the neutrino masses. We describe the science objectives and the initial receiver design. Comment: 21 pages, 7 figures
06/2010;
-
J. E. Austermann,
M. D. Niemack,
J. W. Appel,
J. A. Beall,
D. Becker,
D. A. Bennett,
B. A. Benson,
L. E. Bleem,
J. Britton,
J. E. Carlstrom, [......],
J. McMahon,
J. Mehl,
S. S. Meyer,
L. P. Parker,
S. M. Simon,
S. T. Staggs,
J. N. Ullom,
C. Visnjic, K. W. Yoon,
Y. Zhao
[show abstract]
[hide abstract]
ABSTRACT: We are developing feedhorn‐coupled TES polarimeters to measure the polarization anisotropies of the cosmic microwave background (CMB) radiation. These devices will be deployed in arrays of hundreds to thousands and will be measured using multiplexed SQUID readout electronics. Since multiplexed devices share common circuitry, a high degree of uniformity is required in the electrothermal properties of the TES bolometers and readout circuits in order to operate all channels simultaneously with high sensitivity. Our cryogenic test bed can probe dozens of devices simultaneously, thus providing useful detector statistics on relatively short time scales. We describe the TES bolometer design and present dark (no optical loading) measurements of the electrical and thermal properties and uniformity of prototype bolometers across two 3‐inch diameter production wafers, including (standard deviation in parenthesis): TES transition temperature (∼1%), normal resistance (∼10%), thermal conductance (≲10%), time constant (∼20%), shunt resistance (≲5%), and noise properties.
AIP Conference Proceedings. 12/2009; 1185(1):498-501.
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J. J. McMahon,
K. A. Aird,
B. A. Benson,
L. E. Bleem,
J. Britton,
J. E. Carlstrom,
C. L. Chang,
H. S. Cho,
T. de Haan,
T. M. Crawford, [......],
A. A. Stark,
Z. Staniszewski,
K. Vanderlinde,
J. D. Vieira,
G. Wang,
R. Williamson,
V. Yefremenko, K. W. Yoon,
O. Zhan,
A. Zenteno
[show abstract]
[hide abstract]
ABSTRACT: SPTpol will consist of an 850 element polarization sensitive bolometric camera deployed to the South Pole Telescope in late 2011. This camera is optimized for measurement of the polarization of the cosmic microwave background with arcminute resolution. These measurements will be used to constrain neutrino masses and to constrain the amplitude of gravitational waves from inflation. The camera includes two detector architectures that observe in two different frequency bands. At 150 GHz, SPTpol will use 650 feedhorn‐coupled TES polarimeters fabricated at NIST. At 90 GHz, it will use 200 absorber‐coupled polarimeters developed at Argonne National Lab. The NIST pixels will be coupled to the telescope using a monolithic array of corrugated feeds and the Argonne devices will be coupled with individually machined contoured feeds. The entire focal plane will be readout using a digital frequency‐domain multiplexer system. We provide an overview of the project, describe the detectors and discuss the design of this system.
AIP Conference Proceedings. 12/2009; 1185(1):511-514.
-
K. W. Yoon,
P. A. Ade,
D. Barkats,
J. O. Battle,
E. M. Bierman,
J. J. Bock,
H. C. Chiang,
C. D. Dowell,
L. Duband,
G. S. Griffin, [......],
V. V. Hristov,
B. G. Keating,
J. M. Kovac,
C. Kuo,
A. E. Lange,
E. M. Leitch,
P. V. Mason,
H. T. Nguyen,
N. Ponthieu,
Y. D. Takahashi
[show abstract]
[hide abstract]
ABSTRACT: BICEP is a small-aperture polarimeter which began observing the CMB from
South Pole in January 2006. BICEP's 25 cm refracting telescope feeds an
array of 49 polarization-sensitive bolometer pairs operating at 100 and
150 GHz. A three-axis mount provides azimuth-scanning modulation,
elevation coverage from 45 degrees to zenith, and boresight rotation of
the entire instrument for polarization systematic error control. We
report on the first winter observations of the CMB and Galaxy at degree
angular scales.
BICEP is funded by NSF/Office of Polar Programs, Caltech, JPL, and the
estate of J. Robinson.
11/2006; 38:963.
-
K. W. Yoon,
P. A. R. Ade,
D. Barkats,
J. O. Battle,
E. M. Bierman,
J. J. Bock,
J. A. Brevik,
H C Chiang,
A. Crites,
C. D. Dowell, [......],
C. L. Kuo,
A. E. Lange,
E. M. Leitch,
P. V. Mason,
H T Nguyen,
N. Ponthieu,
Y. D. Takahashi,
T. Renbarger,
L. C. Weintraub,
D. Woolsey
[show abstract]
[hide abstract]
ABSTRACT: The Robinson Telescope (BICEP) is a ground-based millimeter-wave bolometric array designed to study the polarization of the cosmic microwave background radiation (CMB) and galactic foreground emission. Such measurements probe the energy scale of the inflationary epoch, tighten constraints on cosmological parameters, and verify our current understanding of CMB physics. Robinson consists of a 250-mm aperture refractive telescope that provides an instantaneous field-of-view of 17 degrees with angular resolution of 55 and 37 arcminutes at 100 GHz and 150 GHz, respectively. Forty-nine pair of polarization-sensitive bolometers are cooled to 250 mK using a 4He/3He/3He sorption fridge system, and coupled to incoming radiation via corrugated feed horns. The all-refractive optics is cooled to 4 K to minimize polarization systematics and instrument loading. The fully steerable 3-axis mount is capable of continuous boresight rotation or azimuth scanning at speeds up to 5 deg/s. Robinson has begun its first season of observation at the South Pole. Given the measured performance of the instrument along with the excellent observing environment, Robinson will measure the E-mode polarization with high sensitivity, and probe for the B-modes to unprecedented depths. In this paper we discuss aspects of the instrument design and their scientific motivations, scanning and operational strategies, and the results of initial testing and observations. Comment: 18 pages, 11 figures. To appear in Millimeter and Submillimeter Detectors and Instrumentation for Astronomy III, Proceedings of SPIE, 6275, 2006
06/2006;
-
[show abstract]
[hide abstract]
ABSTRACT: We are developing monolithic arrays of corrugated feed horns fabricated in silicon for dual-polarization single-mode operation at 90, 145 and 220 GHz. The arrays consist of hundreds of platelet feed horns assembled from gold-coated stacks of micro-machined silicon wafers. As a first step, Au-coated Si waveguides with a circular, corrugated cross section were fabricated; their attenuation was measured to be less than 0.15 dB/cm from 80 to 110 GHz at room temperature. To ease the manufacture of horn arrays, electrolytic deposition of Au on degenerate Si without a metal seed layer was demonstrated. An apparatus for measuring the radiation pattern, optical efficiency, and spectral band-pass of prototype horns is described. Feed horn arrays made of silicon may find use in measurements of the polarization anisotropy of the cosmic microwave background radiation. Imaging detectors at millimeter wavelengths can now be built with hundreds of pixels.[1] However, parallel gains in free-space coupling optics have lagged.
