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Showing papers by "W. L. Holzapfel published in 2020"


Journal ArticleDOI
Lindsey Bleem1, Sebastian Bocquet1, Sebastian Bocquet2, B. Stalder3  +156 moreInstitutions (56)
TL;DR: In this paper, the authors describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS), and associate SZ-selected clusters, from both SPT-ECS and the SPT SZ survey, with clusters from the DES redMaPPer sample, and find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets.
Abstract: We describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance ξ ≥ 5 and an additional 204 systems at 4 4 threshold, and 10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass (l - M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data-a difference significant at the 4σ level-with the relations intersecting at λ = 60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses.

72 citations


Journal ArticleDOI
TL;DR: In this article, the authors report a B-mode power spectrum measurement from the cosmic microwave background (CMB) polarization anisotropy observations made using the SPTpol instrument on the South Pole Telescope.
Abstract: We report a B-mode power spectrum measurement from the cosmic microwave background (CMB) polarization anisotropy observations made using the SPTpol instrument on the South Pole Telescope. This work uses 500 deg2 of SPTpol data, a five-fold increase over the last SPTpol B-mode release. As a result, the bandpower uncertainties have been reduced by more than a factor of two, and the measurement extends to lower multipoles: 52 320.

69 citations


Journal ArticleDOI
TL;DR: In this article, a search for anisotropic cosmic birefringence in the southern sky at 150 GHz with the SPTpol camera on the South Pole Telescope is presented.
Abstract: We present a search for anisotropic cosmic birefringence in 500 deg2 of southern sky observed at 150 GHz with the SPTpol camera on the South Pole Telescope. We reconstruct a map of cosmic polarization rotation anisotropies using higher-order correlations between the observed cosmic microwave background (CMB) E and B fields. We then measure the angular power spectrum of this map, which is found to be consistent with zero. The nondetection is translated into an upper limit on the amplitude of the scale-invariant cosmic rotation power spectrum, L(L+1)CααL/2π<0.10×10−4 rad2 (0.033 deg2, 95% C.L.). This upper limit can be used to place constraints on the strength of primordial magnetic fields, B1 Mpc<17 nG (95% C.L.), and on the coupling constant of the Chern-Simons electromagnetic term gaγ<4.0×10−2/HI (95% C.L.), where HI is the inflationary Hubble scale. For the first time, we also cross-correlate the CMB temperature fluctuations with the reconstructed rotation angle map, a signal expected to be nonvanishing in certain theoretical scenarios, and find no detectable signal. We perform a suite of systematics and consistency checks and find no evidence for contamination.

56 citations


Journal ArticleDOI
TL;DR: In this article, the cosmological constraints based on the cosmic microwave background (CMB) lensing potential power spectrum measurement from the recent 500 deg2 SPTpol survey were presented.
Abstract: We present cosmological constraints based on the cosmic microwave background (CMB) lensing potential power spectrum measurement from the recent 500 deg2 SPTpol survey, the most precise CMB lensing measurement from the ground to date. We fit a flat ΛCDM model to the reconstructed lensing power spectrum alone and in addition with other data sets: baryon acoustic oscillations (BAO), as well as primary CMB spectra from Planck and SPTpol. The cosmological constraints based on SPTpol and Planck lensing band powers are in good agreement when analyzed alone and in combination with Planck full-sky primary CMB data. With weak priors on the baryon density and other parameters, the SPTpol CMB lensing data alone provide a 4% constraint on ${\sigma }_{8}{{\rm{\Omega }}}_{m}^{0.25}=0.593\pm 0.025$. Jointly fitting with BAO data, we find ${\sigma }_{8}=0.779\pm 0.023$, ${{\rm{\Omega }}}_{m}={0.368}_{-0.037}^{+0.032}$, and ${H}_{0}={72.0}_{-2.5}^{+2.1}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$, up to $2\sigma $ away from the central values preferred by Planck lensing + BAO. However, we recover good agreement between SPTpol and Planck when restricting the analysis to similar scales. We also consider single-parameter extensions to the flat ΛCDM model. The SPTpol lensing spectrum constrains the spatial curvature to be ${{\rm{\Omega }}}_{K}=-0.0007\pm 0.0025$ and the sum of the neutrino masses to be $\sum {m}_{ u }\lt 0.23$ eV at 95% C.L. (with Planck primary CMB and BAO data), in good agreement with the Planck lensing results. With the differences in the signal-to-noise ratio of the lensing modes and the angular scales covered in the lensing spectra, this analysis represents an important independent check on the full-sky Planck lensing measurement.

50 citations


Journal ArticleDOI
N. Huang1, Lindsey Bleem2, B. Stalder3, Peter A. R. Ade4, Steven W. Allen5, Adam Anderson6, Jason E. Austermann7, Jessica Avva1, James A. Beall7, Amy N. Bender2, Bradford Benson6, Bradford Benson8, Federico Bianchini9, Sebastian Bocquet10, Sebastian Bocquet2, Mark Brodwin11, John E. Carlstrom, C. L. Chang8, C. L. Chang2, H. C. Chiang12, H. C. Chiang13, Robert I. Citron8, C. Corbett Moran8, C. Corbett Moran14, T. M. Crawford8, A. T. Crites8, A. T. Crites14, T. de Haan15, T. de Haan1, Matt Dobbs13, Matt Dobbs16, W. B. Everett17, Benjamin Floyd11, Jason Gallicchio18, Elizabeth George1, Elizabeth George19, A. Gilbert13, Michael D. Gladders8, S. Guns1, Nikhel Gupta9, N. W. Halverson17, N. L. Harrington1, Jason W. Henning2, Gene C. Hilton7, Gilbert Holder16, Gilbert Holder20, W. L. Holzapfel1, J. D. Hrubes8, Johannes Hubmayr7, Kent D. Irwin5, G. Khullar8, Lloyd Knox21, Adrian T. Lee15, Adrian T. Lee1, Dale Li5, Dale Li7, A. E. Lowitz8, Michael McDonald22, Jeff McMahon23, S. S. Meyer, L. M. Mocanu8, L. M. Mocanu24, Joshua Montgomery13, A. Nadolski20, T. Natoli8, T. Natoli25, John P. Nibarger7, G. I. Noble13, Valentine Novosad2, Stephen Padin14, Stephen Padin8, S. Patil9, C. Pryke26, Christian L. Reichardt9, J. E. Ruhl27, Benjamin Saliwanchik28, A. Saro29, J. T. Sayre17, K. K. Schaffer30, K. K. Schaffer8, Keren Sharon23, C. Sievers8, Graeme Smecher13, Antony A. Stark3, K. T. Story5, Carole Tucker4, K. Vanderlinde25, T. Veach31, Joaquin Vieira20, Gensheng Wang2, Nathan Whitehorn32, W. L. K. Wu, Volodymyr Yefremenko2 
TL;DR: In this article, the authors presented a catalog of galaxy cluster candidates detected in 100 square degrees surveyed with the SPTpol receiver on the South Pole Telescope, which contains 89 candidates detected with a signal-to-noise ratio greater than 4.6.
Abstract: We present a catalog of galaxy cluster candidates detected in 100 square degrees surveyed with the SPTpol receiver on the South Pole Telescope. The catalog contains 89 candidates detected with a signal-to-noise ratio greater than 4.6. The candidates are selected using the Sunyaev–Zel'dovich effect at 95 and 150 GHz. Using both space- and ground-based optical and infrared telescopes, we have confirmed 81 candidates as galaxy clusters. We use these follow-up images and archival images to estimate photometric redshifts for 66 galaxy clusters and spectroscopic observations to obtain redshifts for 13 systems. An additional two galaxy clusters are confirmed using the overdensity of near-infrared galaxies only and are presented without redshifts. We find that 15 candidates (18% of the total sample) are at redshift z ≥ 1.0, with a maximum confirmed redshift of ${z}_{\max }=1.38\pm 0.10$. We expect this catalog to contain every galaxy cluster with ${M}_{500c}\gt 2.6\times {10}^{14}{M}_{\odot }{{h}}_{70}^{-1}$ and z > 0.25 in the survey area. The mass threshold is approximately constant above z = 0.25, and the complete catalog has a median mass of approximately ${M}_{500c}=2.7\times {10}^{14}{M}_{\odot }{{h}}_{70}^{-1}$. Compared to previous SPT works, the increased depth of the millimeter-wave data (11.2 and 6.5 μK-arcmin at 95 and 150 GHz, respectively) makes it possible to find more galaxy clusters at high redshift and lower mass.

46 citations


Journal ArticleDOI
TL;DR: In this article, the authors presented a catalog of emissive point sources detected in the SPT-SZ survey, a contiguous 2530 square degree area surveyed with the South Pole Telescope (SPT) from 2008-2011 in three bands centered at 95, 150, and 220 GHz.
Abstract: We present a catalog of emissive point sources detected in the SPT-SZ survey, a contiguous 2530 square degree area surveyed with the South Pole Telescope (SPT) from 2008–2011 in three bands centered at 95, 150, and 220 GHz. The catalog contains 4845 sources measured at a significance of 4.5σ or greater in at least one band, corresponding to detections above approximately 9.8, 5.8, and 20.4 mJy in 95, 150, and 220 GHz, respectively. The spectral behavior in the SPT bands is used for source classification into two populations based on the underlying physical mechanisms of compact, emissive sources that are bright at millimeter wavelengths: synchrotron radiation from active galactic nuclei and thermal emission from dust. The latter population includes a component of high-redshift sources often referred to as submillimeter galaxies (SMGs). In the relatively bright flux ranges probed by the survey, these sources are expected to be magnified by strong gravitational lensing. The survey also contains sources consistent with protoclusters, groups of dusty galaxies at high redshift undergoing collapse. We cross-match the SPT-SZ catalog with external catalogs at radio, infrared, and X-ray wavelengths and identify available redshift information. The catalog splits into 3980 synchrotron-dominated and 865 dust-dominated sources, and we determine a list of 506 SMGs. Ten sources in the catalog are identified as stars. We calculate number counts for the full catalog, and synchrotron and dusty components, using a bootstrap method and compare our measured counts with models. This paper represents the third and final catalog of point sources in the SPT-SZ survey.

38 citations


Journal ArticleDOI
Christian L. Reichardt1, S. Patil1, P. A. R. Ade2, Adam Anderson3, Jason E. Austermann4, Jason E. Austermann5, Jessica Avva6, Eric J. Baxter7, James A. Beall5, Amy N. Bender8, Bradford Benson9, Bradford Benson3, Federico Bianchini1, Lindsey Bleem8, John E. Carlstrom9, John E. Carlstrom8, C. L. Chang9, C. L. Chang8, P. Chaubal1, H. C. Chiang10, H. C. Chiang11, T. L. Chou9, Robert I. Citron9, C. Corbett Moran12, T. M. Crawford9, A. T. Crites9, A. T. Crites12, T. de Haan6, T. de Haan13, M. A. Dobbs10, M. A. Dobbs14, W. B. Everett4, Jason Gallicchio15, Elizabeth George6, Elizabeth George16, A. Gilbert10, Nikhel Gupta1, N. W. Halverson4, N. L. Harrington6, Jason W. Henning8, Gene C. Hilton5, Gilbert Holder14, Gilbert Holder17, W. L. Holzapfel6, J. D. Hrubes9, N. Huang6, Johannes Hubmayr5, Kent D. Irwin18, Lloyd Knox19, Adrian T. Lee13, Adrian T. Lee6, Dale Li18, Dale Li5, A. E. Lowitz9, Daniel M. Luong-Van9, Jeff McMahon20, J. Mehl9, S. S. Meyer9, Marius Millea19, L. M. Mocanu9, Joseph J. Mohr21, Joshua Montgomery10, A. Nadolski17, T. Natoli22, T. Natoli9, John P. Nibarger5, G. I. Noble10, Valentyn Novosad8, Y. Omori18, S. Padin9, S. Padin12, C. Pryke, J. E. Ruhl23, Benjamin Saliwanchik23, Benjamin Saliwanchik24, J. T. Sayre4, J. T. Sayre23, K. K. Schaffer25, K. K. Schaffer9, Erik Shirokoff, C. Sievers9, Graeme Smecher10, Helmuth Spieler13, Z. K. Staniszewski23, Antony A. Stark26, Carole Tucker2, Keith Vanderlinde22, T. Veach27, Joaquin Vieira17, Gensheng Wang8, Nathan Whitehorn28, R. Williamson9, W. L. K. Wu, Volodymyr Yefremenko8 
TL;DR: In this article, the authors reported new measurements of millimeter-wave power spectra in the angular multipole range (APM) of the angular scales of the SZ and SZ bispectrum.
Abstract: We report new measurements of millimeter-wave power spectra in the angular multipole range $2000 \le \ell \le 11,000$ (angular scales $5^\prime \gtrsim \theta \gtrsim 1^\prime$). By adding 95 and 150\,GHz data from the low-noise 500 deg$^2$ SPTpol survey to the SPT-SZ three-frequency 2540 deg$^2$ survey, we substantially reduce the uncertainties in these bands. These power spectra include contributions from the primary cosmic microwave background, cosmic infrared background, radio galaxies, and thermal and kinematic Sunyaev-Zel'dovich (SZ) effects. The data favor a thermal SZ (tSZ) power at 143\,GHz of $D^{\rm tSZ}_{3000} = 3.42 \pm 0.54~ \mu {\rm K}^2$ and a kinematic SZ (kSZ) power of $D^{\rm kSZ}_{3000} = 3.0 \pm 1.0~ \mu {\rm K}^2$. This is the first measurement of kSZ power at $\ge 3\,\sigma$. We study the implications of the measured kSZ power for the epoch of reionization, finding the duration of reionization to be $\Delta z_{re} = 1.0^{+1.6}_{-0.7}$ ($\Delta z_{re}< 4.1$ at 95% confidence), when combined with our previously published tSZ bispectrum measurement.

25 citations


Proceedings ArticleDOI
13 Dec 2020
TL;DR: An updated derivation for electrical crosstalk in higher-bandwidth DfMUX systems is presented, and two previously uncharacterized contributions to readout noise are identified.
Abstract: The third generation South Pole Telescope camera (SPT-3G) improves over its predecessor (SPTpol) by an order of magnitude increase in detector number. The technology used to read out and control these detectors, digital frequency-domain multiplexing (DfMUX), is conceptually the same as used for SPTpol, but extended to accommodate more detectors. A nearly 5x expansion in the readout operating bandwidth has enabled the use of this large focal plane, and SPT-3G performance meets the forecasting targets relevant to its science objectives. However, the electrical dynamics of the higher-bandwidth system depart in significant ways from the characterization and models drawn from the previous generation of cameras. We present an updated derivation for electrical crosstalk in higher-bandwidth DfMUX systems, and identify two previously uncharacterized contributions to readout noise. The updated crosstalk and noise models successfully describe the measured crosstalk and readout noise performance of SPT-3G, and suggest improvements to the readout system for future experiments using DfMUX, such as the LiteBIRD satellite.

12 citations


Journal ArticleDOI
Amy N. Bender1, Amy N. Bender2, Adam Anderson1, Adam Anderson3, Jessica Avva4, Peter A. R. Ade5, Zeeshan Ahmed6, Zeeshan Ahmed7, Peter S. Barry1, Peter S. Barry2, R. Basu Thakur1, Bradford Benson3, Bradford Benson1, Lincoln Bryant1, Karen Byrum2, John E. Carlstrom, Faustin Carter1, Faustin Carter2, Thomas Cecil2, C. L. Chang2, C. L. Chang1, H. M. Cho6, J. F. Cliche8, Ari Cukierman4, T. de Haan4, E. V. Denison9, Junjia Ding2, Matt Dobbs8, Matt Dobbs10, D. Dutcher1, W. B. Everett11, K. R. Ferguson12, A. Foster13, J. Fu14, Jason Gallicchio15, Jason Gallicchio1, A. E. Gambrel1, Robert Gardner1, A. Gilbert8, John Groh4, S. Guns4, R. Guyser14, N. W. Halverson11, A. H. Harke-Hosemann14, A. H. Harke-Hosemann2, N. L. Harrington4, Jason W. Henning2, Jason W. Henning1, Gene C. Hilton9, W. L. Holzapfel4, D. Howe1, N. Huang4, Kent D. Irwin6, Kent D. Irwin7, Oliver Jeong4, M. Jonas3, Aled Jones1, Trupti Khaire2, A. M. Kofman14, M. Korman13, Donna Kubik3, Steve Kuhlmann2, Chao-Lin Kuo6, Chao-Lin Kuo7, Adrian T. Lee4, Adrian T. Lee16, E. M. Leitch1, A. E. Lowitz1, S. S. Meyer, Daniel Michalik1, Joshua Montgomery8, Andrew Nadolski14, T. Natoli17, H. T. Nguyen3, G. I. Noble8, V. Novosad2, Stephen Padin1, Z. Pan1, P. Paschos1, John E. Pearson2, C. M. Posada2, W. Quan1, Alexandra S. Rahlin1, Alexandra S. Rahlin3, D. Riebel1, J. E. Ruhl13, J. T. Sayre11, Erik Shirokoff1, Graeme Smecher, J. A. Sobrin1, Antony A. Stark18, J. Stephen1, K. T. Story7, Aritoki Suzuki16, Keith L. Thompson6, Keith L. Thompson7, Carole Tucker5, Leila R. Vale9, K. Vanderlinde17, Joaquin Vieira14, Gensheng Wang2, Nathan Whitehorn12, Volodymyr Yefremenko2, Ki Won Yoon6, Ki Won Yoon7, M. R. Young17 
TL;DR: In this article, the authors present the successful implementation and performance of the South Pole Telescope 3G readout as measured on-sky, showing that low-frequency noise in the readout will not limit sky power on large angular scales.
Abstract: Frequency-domain multiplexing (fMux) is an established technique for the readout of large arrays of transition-edge sensor (TES) bolometers. Each TES in a multiplexing module has a unique AC voltage bias that is selected by a resonant filter. This scheme enables the operation and readout of multiple bolometers on a single pair of wires, reducing thermal loading onto sub-Kelvin stages. The current receiver on the South Pole Telescope, SPT-3G, uses a 68x fMux system to operate its large-format camera of ∼ ∼ 16,000 TES bolometers. We present here the successful implementation and performance of the SPT-3G readout as measured on-sky. Characterization of the noise reveals a median pair-differenced 1/f knee frequency of 33 mHz, indicating that low-frequency noise in the readout will not limit SPT-3G’s measurements of sky power on large angular scales. Measurements also show that the median readout white noise level in each of the SPT-3G observing bands is below the expectation for photon noise, demonstrating that SPT-3G is operating in the photon-noise-dominated regime.

10 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed a frequency-domain multiplexing-based CMB-S4 system, which is the state-of-the-art on-sky CMB measurement system.
Abstract: Cosmic microwave background (CMB) measurements are fundamentally limited by photon statistics. Therefore, ground-based CMB observatories have been increasing the number of detectors that are simultaneously observing the sky. Thanks to the advent of monolithically fabricated transition edge sensor arrays, the number of on-sky detectors has been increasing exponentially for over a decade. The next-generation experiment CMB-S4 will increase this detector count by more than an order of magnitude from the current state of the art to 500,000. The readout of such a huge number of exquisitely precise sub-Kelvin sensors is feasible using an existing technology: frequency-domain multiplexing. To further optimize this system and reduce complexity and cost, we have recently made significant advances including the elimination of 4 K electronics, a massive decrease in parasitic in-series impedances, and a significant increase in multiplexing factor.

8 citations


Journal ArticleDOI
Adam Anderson1, Adam Anderson2, Peter A. R. Ade3, Zeeshan Ahmed4, Zeeshan Ahmed5, Jessica Avva6, Peter S. Barry7, Peter S. Barry2, R. Basu Thakur2, Amy N. Bender2, Amy N. Bender7, Bradford Benson2, Bradford Benson1, Lincoln Bryant2, Karen Byrum7, John E. Carlstrom, Faustin Carter7, Faustin Carter2, Thomas Cecil7, C. L. Chang2, C. L. Chang7, H. M. Cho4, J. F. Cliche8, Ari Cukierman6, T. de Haan6, E. V. Denison9, Junjia Ding7, Matt Dobbs10, Matt Dobbs8, D. Dutcher2, W. B. Everett11, K. R. Ferguson12, A. Foster13, J. Fu14, Jason Gallicchio15, Jason Gallicchio2, A. E. Gambrel2, Robert Gardner2, A. Gilbert8, John Groh6, S. Guns6, R. Guyser14, N. W. Halverson11, A. H. Harke-Hosemann7, A. H. Harke-Hosemann14, N. L. Harrington6, Jason W. Henning2, Jason W. Henning7, Gene C. Hilton9, W. L. Holzapfel6, D. Howe2, N. Huang6, Kent D. Irwin5, Kent D. Irwin4, Oliver Jeong6, M. Jonas1, Aled Jones2, Trupti Khaire7, A. M. Kofman14, M. Korman13, Donna Kubik1, Steve Kuhlmann7, Chao-Lin Kuo4, Chao-Lin Kuo5, Adrian T. Lee16, Adrian T. Lee6, E. M. Leitch2, A. E. Lowitz2, S. S. Meyer, Daniel Michalik2, Joshua Montgomery8, Andrew Nadolski14, T. Natoli17, H. T. Nguyen1, G. I. Noble8, V. Novosad7, Stephen Padin2, Z. Pan2, P. Paschos2, John E. Pearson7, C. M. Posada7, W. Quan2, Alexandra S. Rahlin2, Alexandra S. Rahlin1, D. Riebel2, J. E. Ruhl13, J. T. Sayre11, Erik Shirokoff2, Graeme Smecher, J. A. Sobrin2, Antony A. Stark18, J. Stephen2, K. T. Story5, Aritoki Suzuki16, Keith L. Thompson4, Keith L. Thompson5, Carole Tucker3, Leila R. Vale9, K. Vanderlinde17, Joaquin Vieira14, Gensheng Wang7, Nathan Whitehorn12, Volodymyr Yefremenko7, Ki Won Yoon4, Ki Won Yoon5, M. R. Young17 
TL;DR: In this article, a transition-edge sensor (TES) wafer was replaced with a new wafer fabricated with Al-Mn TESs instead of the Ti/Au design originally deployed for SPT-3G.
Abstract: SPT-3G is a polarization-sensitive receiver, installed on the South Pole Telescope, that measures the anisotropy of the cosmic microwave background (CMB) from degree to arcminute scales. The receiver consists of ten 150-mm-diameter detector wafers, containing a total of ∼16,000 ∼16,000 transition-edge sensor (TES) bolometers observing at 95, 150, and 220 GHz. During the 2018–2019 austral summer, one of these detector wafers was replaced by a new wafer fabricated with Al–Mn TESs instead of the Ti/Au design originally deployed for SPT-3G. We present the results of in-laboratory characterization and on-sky performance of this Al–Mn wafer, including electrical and thermal properties, optical efficiency measurements, and noise-equivalent temperature. In addition, we discuss and account for several calibration-related systematic errors that affect measurements made using frequency-domain multiplexing readout electronics.

Journal ArticleDOI
TL;DR: In this paper, the authors present two prescriptions for broadband (77 - 252 ε;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large format planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements.
Abstract: We present two prescriptions for broadband ($ {\sim} 77 - 252\;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large-format (700 mm diameter) planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements-in our case, 5 mm diameter half-spheres (called "lenslets"). The coatings comprise three layers of commercially available, polytetrafluoroethylene-based, dielectric sheet material. The lenslet coating is molded to fit the 150 mm diameter arrays directly, while the large-diameter lenses are coated using a tiled approach. We review the fabrication processes for both prescriptions, then discuss laboratory measurements of their transmittance and reflectance. In addition, we present the inferred refractive indices and loss tangents for the coating materials and the aluminum oxide substrate. We find that at 150 GHz and 300 K the large-format coating sample achieves $ (97 \pm 2)\% $ transmittance, and the lenslet coating sample achieves $ (94 \pm 3)\% $ transmittance.

Journal ArticleDOI
01 Feb 2020
TL;DR: In this article, the authors present the status of an on-going 1500 sq. deg. survey with the SPT-3G receiver, a new mm-wavelength camera on the 10m diameter South Pole Telescope (SPT).
Abstract: The cosmic microwave background (CMB) encodes information about the content and evolution of the universe. The presence of light, weakly interacting particles impacts the expansion history of the early universe, which alters the temperature and polarization anisotropies of the CMB. In this way, current measurements of the CMB place interesting constraints on the neutrino energy density and mass, as well as on the abundance of other possible light relativistic particle species. We present the status of an on-going 1500 sq. deg. survey with the SPT-3G receiver, a new mm-wavelength camera on the 10-m diameter South Pole Telescope (SPT). The SPT-3G camera consists of 16,000 superconducting transition edge sensors, a 10x increase over the previous generation camera, which allows it to map the CMB with an unprecedented combination of sensitivity and angular resolution. We highlight projected constraints on the abundance of sterile neutrinos and the sum of the neutrino masses for the SPT-3G survey, which could help determine the neutrino mass hierarchy.

Journal ArticleDOI
TL;DR: In this article, the authors focus on LC bandpass filters with resonances in the 1-5 MHz range used in the transition edge sensor (TES) bolometer readout of the Simons Array cosmic microwave background (CMB) experiment.
Abstract: Superconducting lithographed resonators have a broad range of current and potential applications in the multiplexed readout of cryogenic detectors. Here, we focus on LC bandpass filters with resonances in the 1-5 MHz range used in the transition edge sensor (TES) bolometer readout of the Simons Array cosmic microwave background (CMB) experiment. In this readout scheme, each detector signal amplitude-modulates a sinusoidal carrier tone at the resonance frequency of the detector's accompanying LC filter. Many modulated signals are transmitted over the same wire pair, and quadrature demodulation recovers the complex detector signal. We observe a noise in the resonant frequencies of the LC filters, which presents primarily as a current-dependent noise in the quadrature component after demodulation. This noise has a rich phenomenology, bearing many similarities to that of two-level system (TLS) noise observed in similar resonators in the GHz regime. These similarities suggest a common physical origin, thereby offering a new regime in which the underlying physics might be probed. We further describe an observed non-orthogonality between this noise and the detector responsivities, and present laboratory measurements that bound the resulting sensitivity penalty expected in the Simons Array. From these results, we do not anticipate this noise to appreciably affect the overall Simons Array sensitivity, nor do we expect it to limit future implementations.