Search

A novel, solution immersed silicon (SIS)-based sensor has been developed which employs the non-reflecting condition (NRC) for a p-polarized wave. The SIS sensor's response is almost independent of change in the refractive index (RI) of a buffer solution (BS) which makes it capable of measuring low-concentration and/or low-molecular-weight compounds. [ABSTRACT FROM AUTHOR]

Coherent x-ray diffraction imaging is used to map the local three dimensional strain inhomogeneity and electron density distribution of two individual LiNi0.5Mn1.5O4-δ cathode nanoparticles in both ex-situ and in-situ environments. Our reconstructed images revealed a maximum strain of 0.4%. We observed different variations in strain inhomogeneity due to multiple competing effects. The compressive/tensile component of the strain is connected to the local lithium content and, on the surface, interpreted in terms of a local Jahn-Teller distortion of Mn3+. Finally, the measured strain distributions are discussed in terms of their impact on competing theoretical models of the lithiation process. [ABSTRACT FROM AUTHOR]

Time-division SQUID multiplexers are used in many applications that require exquisite control of systematic error. One potential source of systematic error is the pickup of external magnetic fields in the multiplexer. We present measurements of the field sensitivity figure of merit, effective area, for both the first stage and second stage SQUID amplifiers in three NIST SQUID multiplexer designs. These designs include a new variety with improved gradiometry that significantly reduces the effective area of both the first and second stage SQUID amplifiers. [ABSTRACT FROM AUTHOR]

Focuses on low-frequency noise in field-cooled, directly coupled magnetometers. Noise properties in static magnetic fields; Directly coupled magnetometers with narrow linewidths.

Superconducting transition edge sensors (TES) require superconducting films with transition temperatures (Tc) and properties that can be tailored to the particular requirements of individual applications. We have been developing Al-Mn films with a tunable Tc. The addition of Mn to Al suppresses Tc, but does not significantly broaden the superconducting density of states of the Al. We can produce films with Tc from below 50 mK to 1.4 K through adjustment of the Mn concentration. Since this is a bulk effect, Tc 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. [ABSTRACT FROM AUTHOR]

The transition-edge sensor (TES) is a mature, high-resolution x-ray spectrometer technology that provides a much higher efficiency than dispersive spectrometers such as gratings and crystal spectrometers. As larger arrays are developed, time-division multiplexing schemes operating at MHz frequencies are being replaced by microwave SQUID multiplexers using frequency-division multiplexing at GHz frequencies. However, the multiplexing factor achievable with microwave SQUIDs is limited by the high slew rate on the leading edge of x-ray pulses. In this paper, we propose a new multiplexing scheme for high-slew-rate TES x-ray calorimeters: the spread-spectrum SQUID multiplexer, which has the potential to enable higher multiplexing factors, especially in applications with lower photon-arrival rates. [ABSTRACT FROM AUTHOR]

Transition edge sensors (TESs) have proven to be highly sensitive and versatile X-ray spectrometers. Upcoming missions, including Athena X-IFU, will rely on highly multiplexed focal planes where more than 32 TES pixels are read out using a single SQUID amplifier channel. We have implemented an error correction algorithm for code-division multiplexed TES signals that can compensate for potential failures of individual SQUID readout channels and that is both scalable and easily implemented in hardware. We present this algorithm for error correction and show results of laboratory tests to assess algorithm performance at recovering TES channels after a SQUID failure. [ABSTRACT FROM AUTHOR]

Healthy nutritional status is crucial for obtaining favorable hemodialysis (HD) and transplantation results in chronic renal failure (CRF), because there is a high incidence of malnutrition in these patients. In addition, there is a remarkable loss of amino acids (AAs) during HD. This study examined changes in the serum AA profiles of pre- and post-HD in order to plan a strategy for providing nutritional support to patients on HD. Twenty-nine stable male patients on HD were enrolled in this study. The criteria for patient selection were urine output less than 200 mL/day, 3 times HD a week, and HD treatment for more than 12 months. Total plasma AA concentrations of pre- and post-HD were 2948.4 ± 543.1 and 2279.2 ± 400.8 mol/L, the difference being highly significant (p < 0.0001). There was also a significant decrease in the level of essential AAs (EAAs, 774.4 ± 163.8 vs. 643.4 ± 142.5 μmol/L, p < 0.0005) and non-EAAs (2019.0 ± 411.7 vs. 1539.6 ± 278.3 μmol/L, p < 0.0001) after HD. The ratio of the EAAs to the non-EAAs increased after HD (0.39 ± 0.07 vs. 0.42 ± 0.07 μmol/L). The level of branched chain AAs (BCAAs) of pre- and post-HD was 323.3 ± 73.7 vs. 286.7 ± 71.2 μmol/L and that of aromatic AAs (AAAs) was 180.9 ± 56.2 vs. 137.5 ± 42.6 μmol/L (p < 0.0005), and the BCCA to AAA ratio increased after HD (1.8 ± 0.41 vs. 2.2 ± 0.57 μmol/L, p = 0.01). Among the abnormal AAs which appear in CRF, the concentrations of β-aminobutyric acid, citrulline, 1-methyl histidine, phophoserine, and taurine decreased significantly after HD. Patients revealed a large loss of AAs including abnormal-appearing AAs during HD. The ratios of EAA to non-EAA and BCAA to AAA increase significantly, which indicates the beneficial effect of HD on the metabolic recovery of the AA profile. But replacing AAs, especially EAAs with high BCAAs, is essential for maintaining nutritional status to compensate the significant loss of AAs during HD. [ABSTRACT FROM AUTHOR]

Transition-edge sensor microcalorimeters have found success as X-ray detectors at synchrotron light-sources, due to a unique combination of high collecting area and good energy resolution. However, the upcoming generation of free-electron lasers (FELs), such as the Linac Coherent Light Source II, is designed to deliver more than 10 10 photons in a 100 fs pulse at a 100 kHz rate, potentially leading to severe pulse-pileup issues. We will demonstrate that, for most relevant science cases, it is possible to mitigate pulse pile-up using simple X-ray filters in a way that takes advantage of the substantial increase in X-ray flux at modern FELs. [ABSTRACT FROM AUTHOR]

Self-similar antennas offer extremely broadband functionality and easily scalable designs. Self-similar designs with a four-arm layout are also suited for dual polarization through excitations of opposing arms, although there has only been limited use of them for millimeter-wave detectors. These antennas have been used for measurements of the cosmic microwave background (CMB), which encompass a wide frequency range and are now actively focusing more on polarization anisotropies. We analyze multiple planar self-similar antenna designs with simulations in high-frequency structure simulator and ongoing physical testing. They all exhibit broadband operation between 130 and 230 GHz and can couple to both linear polarizations through the previously mentioned four-arm symmetry. Simulations include each antenna design coupled to an extended hemispherical, AR-coated lenslet. From these, a basic bowtie-like arm design produced minimal polarization wobble with moderate beam efficiency, while a hybrid trapezoidal design provided high beam efficiency with small polarization wobble. Current fabrication versions of each are being tested, coupled to multichroic microwave kinetic inductance detectors. These planar self-similar antennas, when implemented in CMB and other detectors, could improve observations while simultaneously simplifying fabrication and detector layout. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 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. [ABSTRACT FROM AUTHOR]

Multiplexed superconducting quantum interference device (SQUID) readout systems are critical for measuring large arrays of superconducting transition-edge sensors (TES). We demonstrate a code-division SQUID multiplexing (CDM) architecture that is modulated by Walsh codes. Measurements and simulations of a prototype multiplexer show that this modulation scheme is not degraded by SQUID-noise aliasing, suppresses parasitic pickup, and has low levels of crosstalk. These properties enable this architecture to scale to large TES arrays. Furthermore, CDM modulation suppresses the 1/f knee in the noise to below 20 mHz, suggesting the use of this circuit for low-frequency-noise mitigation in more general SQUID applications. [ABSTRACT FROM AUTHOR]

Investigates the effects of microwave irradiation on the I-V characteristics by fabrication and characterization of yttrium-barium-copper-oxygen Josephson junctions with step-edge, bi-epitaxial and sandwich geometries. Use of photolithography and argon ion milling; Overview of reflection high-energy electron diffraction pattern of the thin film.

We are building a transition edge sensor (TES) X-ray spectrometer for the Linac Coherent Light Source (LCLS-II) at SLAC National Accelerator Laboratory (SLAC) to coincide with new upgrades for this free electron laser facility. This new X-ray spectrometer will have 1000 TES pixels with 0.5 eV energy resolution for soft X-rays below 1 keV. Multiplexing will be done with microwave SQUID resonators and new specialized electronic hardware developed at SLAC. This spectrometer will use a dilution refrigerator to achieve lower operating temperatures than previous TES spectrometers and will be coupled to the liquid jet endstation at LCLS-II. The spectrometer is designed to operate at much higher count rates than previous TES X-ray spectrometers to take advantage of the high repetition rate of the LCLS-II. Science applications will utilize the high photon collection efficiency and throughput, high energy resolution, as well as its ability to simultaneously measure its full calibrated energy range. [ABSTRACT FROM AUTHOR]

The high-frequency telescope for LiteBIRD is designed with refractive and reflective optics. In order to improve sensitivity, this paper suggests the new optical configurations of the HFT which have approximately 7 times larger focal planes than that of the original design. The sensitivities of both the designs are compared, and the requirement of anti-reflection (AR) coating on the lens for the refractive option is derived. We also present the simulation result of a sub-wavelength AR structure on both surfaces of silicon, which shows a band-averaged reflection of 1.1-3.2% at 101-448 GHz. [ABSTRACT FROM AUTHOR]

A new receiver for the South Pole Telescope, SPT-3G, was deployed in early 2017 to map the cosmic microwave background at 95, 150, and 220 GHz with ∼ 16,000 detectors, 10 times more than its predecessor SPTpol. The increase in detector count is made possible by lenslet-coupled trichroic polarization-sensitive pixels fabricated at Argonne National Laboratory, new 68× frequency-domain multiplexing readout electronics, and a higher-throughput optical design. The enhanced sensitivity of SPT-3G will enable a wide range of results including constraints on primordial B-mode polarization, measurements of gravitational lensing of the CMB, and a galaxy cluster survey. Here we present an overview of the instrument and its science objectives, highlighting its measured performance and plans for the upcoming 2018 observing season. [ABSTRACT FROM AUTHOR]

We report on the status of an ongoing effort to develop arrays of horn-coupled, polarization-sensitive microwave kinetic inductance detectors (MKIDs) that are each sensitive to two spectral bands between 125 and 280 GHz. These multi-chroic MKID arrays are tailored for next-generation, large-detector-count experiments that are being designed to simultaneously characterize the polarization properties of both the cosmic microwave background and Galactic dust emission. We present our device design and describe laboratory-based measurement results from two 23-element prototype arrays. From dark measurements of our first engineering array, we demonstrated a multiplexing factor of 92, showed the resonators respond to bath temperature changes as expected, and found that the fabrication yield was 100%. From our first optically loaded array, we found the MKIDs respond to millimeter-wave pulses; additional optical characterization measurements are ongoing. We end by discussing our plans for scaling up this technology to kilo-pixel arrays over the next 2 years. [ABSTRACT FROM AUTHOR]

Large arrays of cryogenic sensors for various imaging applications ranging across x-ray, gamma-ray, cosmic microwave background, mm/sub-mm, as well as particle detection increasingly rely on superconducting microresonators for high multiplexing factors. These microresonators take the form of microwave SQUIDs that couple to transition-edge sensors or microwave kinetic inductance detectors. In principle, such arrays can be read out with vastly scalable software-defined radio using suitable FPGAs, ADCs and DACs. In this work, we share plans and show initial results for SLAC Microresonator Radio Frequency (SMuRF) electronics, a next-generation control and readout system for superconducting microresonators. SMuRF electronics are unique in their implementation of specialized algorithms for closed-loop tone tracking, which consists of fast feedback and feedforward to each resonator’s excitation parameters based on transmission measurements. Closed-loop tone tracking enables improved system linearity, a significant increase in sensor count per readout line, and the possibility of overcoupled resonator designs for enhanced dynamic range. Low-bandwidth prototype electronics were used to demonstrate closed-loop tone tracking on twelve 300-kHz-wide microwave SQUID resonators, spaced at ∼ 6 MHz with center frequencies ∼ 5-6 GHz. We achieve multi-kHz tracking bandwidth and demonstrate that the noise floor of the electronics is subdominant to the noise intrinsic in the multiplexer. [ABSTRACT FROM AUTHOR]

In the next decade, new ground-based cosmic microwave background (CMB) experiments such as Simons Observatory, CCAT-prime, and CMB-S4 will increase the number of detectors observing the CMB by an order of magnitude or more, dramatically improving our understanding of cosmology and astrophysics. These projects will deploy receivers with as many as hundreds of thousands of transition edge sensor (TES) bolometers coupled to superconducting quantum interference device (SQUID)-based readout systems. It is well known that superconducting devices such as TESes and SQUIDs are sensitive to magnetic fields. However, the effects of magnetic fields on TESes are not easily predicted due to the complex behavior of the superconducting transition, which motivates direct measurements of the magnetic sensitivity of these devices. We present comparative four-lead measurements of the critical temperature versus applied magnetic field of AlMn TESes varying in geometry, doping, and leg length, including Advanced ACT and POLARBEAR-2/Simons Array bolometers. MoCu ACTPol TESes are also tested and are found to be more sensitive to magnetic fields than the AlMn devices. We present an observation of weak-link-like behavior in AlMn TESes at low critical currents. We also compare measurements of magnetic sensitivity for time division multiplexing SQUIDs and frequency division multiplexing microwave (μMUX) rf-SQUIDs. We discuss the implications of our measurements on the magnetic shielding required for future experiments that aim to map the CMB to near-fundamental limits. [ABSTRACT FROM AUTHOR]

1. A dose-response experiment was conducted with male Korean native ducklings (KND) to evaluate the total sulphur amino acid (TSAA) requirement from hatch to 21 d of age. 2. A completely randomised design with 7 dietary TSAA concentrations (0.62%, 0.65%, 0.68%, 0.71%, 0.74%, 0.77% and 0.80%) were used with 6 replications per treatment. 3. Body weight (BW) and feed intake were measured weekly to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR). One duckling per pen (n = 6) was killed by cervical dislocation to weigh empty body and drumsticks at the conclusion of experiment. 4. BW was improved significantly with increasing TSAA content, in a non-linear manner. A significant decrease of FCR was shown with increasing TSAA contents. TSAA requirement was determined by taking a mean value after fitting the data to both a linear-plateau and a quadratic-plateau model. Estimated TSAA requirements were 0.70%, 0.70%, 0.66% and 0.70% for the maximum BW, ADG and ADFI and for the minimum FCR, respectively. Increasing TSAA content improved quantity of full body weight (FBW), empty body weight (EBW) and drumstick weight (DSW), but there was no effect on proportion of DSW in relation to EBW and proportion of EBW to FBW. 5. In conclusion, the growth of male KND during 1 to 21 d of age was improved with increasing TSAA content, suggesting optimal TSAA requirements estimated by two analysis models. [ABSTRACT FROM AUTHOR]

In this paper, we describe the optimization of transition-edge-sensor (TES) detector arrays for the third-generation camera for the South Pole Telescope. The camera, which contains ∼16 000 detectors, will make high-angular-resolution maps of the temperature and polarization of the cosmic microwave background. Our key results are scatter in the transition temperature of Ti/Au TESs is reduced by fabricating the TESs on a thin Ti(5 nm)/Au(5 nm) buffer layer and the thermal conductivity of the legs that support our detector islands is dominated by the SiOx dielectric in the microstrip transmission lines that run along the legs. [ABSTRACT FROM PUBLISHER]

Aluminum lumped-element kinetic inductance detectors (LEKIDs) sensitive to millimeter-wave photons have been shown to exhibit high quality factors, making them highly sensitive and multiplexable. The superconducting gap of aluminum limits aluminum LEKIDs to photon frequencies above 100 GHz. Manganese-doped aluminum (Al-Mn) has a tunable critical temperature and could therefore be an attractive material for LEKIDs sensitive to frequencies below 100 GHz if the internal quality factor remains sufficiently high when manganese is added to the film. To investigate, we measured some of the key properties of Al-Mn LEKIDs. A prototype eight-element LEKID array was fabricated using a 40 nm thick film of Al-Mn deposited on a 500 μm thick high-resistivity, float-zone silicon substrate. The manganese content was 900 ppm, the measured Tc=694±1mK, and the resonance frequencies were near 150 MHz. Using measurements of the forward scattering parameter S21 at various bath temperatures between 65 and 250 mK, we determined that the Al-Mn LEKIDs we fabricated have internal quality factors greater than 2x105, which is high enough for millimeter-wave astrophysical observations. In the dark conditions under which these devices were measured, the fractional frequency noise spectrum shows a shallow slope that depends on bath temperature and probe tone amplitude, which could be two-level system noise. The anticipated white photon noise should dominate this level of low-frequency noise when the detectors are illuminated with millimeter-waves in future measurements. The LEKIDs responded to light pulses from a 1550 nm light-emitting diode, and we used these light pulses to determine that the quasiparticle lifetime is 60 μs. [ABSTRACT FROM AUTHOR]

Complex optical properties (ε = ε1 + iε2) of polycrystalline bulk α-Ag2S are investigated by spectroscopic ellipsometry from 0.5 to 8.5 eV at room temperature. The acanthite structure (monoclinic) of α-Ag2S is confirmed by structural analysis. Multilayer analysis with Tauc-Lorentz dispersion model is applied to draw out ε from ellipsometric data. Ag2S shows absorption in the entire range of the visible spectrum with onset band gap of 1.07 eV; furthermore, six other interband transitions are identified whose energy positions accurately obtained by standard lineshape analysis of second-energy-derivative of point-by-point fit determined ε. Finally, we compared our data with reported theoretically calculated data, and origin of the main optical structures is discussed. [ABSTRACT FROM AUTHOR]

Topological defects can markedly alter nanomaterial properties. This presents opportunities for "defect engineering,' where desired functionalities are generated through defect manipulation. However, imaging defects in working devices with nanoscale resolution remains elusive. We report three-dimensional imaging of dislocation dynamics in individual battery cathode nanoparticles under operando conditions using Bragg coherent diffractive imaging. Dislocations are static at room temperature and mobile during charge transport. During the structural phase transformation, the lithium-rich phase nucleates near the dislocation and spreads inhomogeneously. The dislocation field is a local probe of elastic properties, and we find that a region of the material exhibits a negative Poisson's ratio at high voltage. Operando dislocation imaging thus opens a powerful avenue for facilitating improvement and rational design of nanostructured materials. [ABSTRACT FROM AUTHOR]

We use microwave observations from the South Pole Telescope (SPT) to examine the Sunyaev-Zel'dovich effect (SZE) signatures of a sample of 46 X-ray selected groups and clusters drawn from ∼6 deg² of the XMM-Newton Blanco Cosmology Survey. These systems extend to redshift z = 1.02 and probe the SZE signal to the lowest X-ray luminosities (≥1042 erg s−1) yet; these sample characteristics make this analysis complementary to previous studies. We develop an analysis tool, using X-ray luminosity as a mass proxy, to extract selection-bias-corrected constraints on the SZE significance and Y500 mass relations. The former is in good agreement with an extrapolation of the relation obtained from high-mass clusters. However, the latter, at low masses, while in good agreement with the extrapolation from the high-mass SPT clusters, is in tension at 2.8σ with the Planck constraints, indicating the low-mass systems exhibit lower SZE signatures in the SPT data. We also present an analysis of potential sources of contamination. For the radio galaxy point source population, we find 18 of our systems have 843 MHz Sydney University Molonglo Sky Survey sources within 2 arcmin of the X-ray centre, and three of these are also detected at significance >4 by SPT. Of these three, two are associated with the group brightest cluster galaxies, and the third is likely an unassociated quasar candidate. We examine the impact of these point sources on our SZE scaling relation analyses and find no evidence of biases. We also examine the impact of dusty galaxies using constraints from the 220 GHz data. The stacked sample provides 2.8σ significant evidence of dusty galaxy flux, which would correspond to an average underestimate of the SPT Y500 signal that is (17 ± 9) per cent in this sample of low-mass systems. Finally, we explore the impact of future data from SPTpol and XMM-XXL, showing that it will lead to a factor of 4 to 5 tighter constraints on these SZE mass-observable relations. [ABSTRACT FROM AUTHOR]

We demonstrate photon-noise limited performance at sub-millimeter wavelengths in feedhorncoupled, microwave kinetic inductance detectors made of a TiN/Ti/TiN trilayer superconducting film, tuned to have a transition temperature of 1.4 K. Micro-machining of the silicon-on-insulator wafer backside creates a quarter-wavelength backshort optimized for efficient coupling at 250 μm. Using frequency read out and when viewing a variable temperature blackbody source, we measure device noise consistent with photon noise when the incident optical power is >0.5 pW, corresponding to noise equivalent powers >3 ╳ 10-17W/√Hz . This sensitivity makes these devices suitable for broadband photometric applications at these wavelengths. [ABSTRACT FROM AUTHOR]

We demonstrate photon-noise limited performance at sub-millimeter wavelengths in feedhorncoupled, microwave kinetic inductance detectors made of a TiN/Ti/TiN trilayer superconducting film, tuned to have a transition temperature of 1.4 K. Micro-machining of the silicon-on-insulator wafer backside creates a quarter-wavelength backshort optimized for efficient coupling at 250 im. Using frequency read out and when viewing a variable temperature blackbody source, we measure device noise consistent with photon noise when the incident optical power is >0.5 pW, corresponding to noise equivalent powers >3 × 10-17 W/√Hz. This sensitivity makes these devices suitable for broadband photometric applications at these wavelengths. [ABSTRACT FROM AUTHOR]

The stability of Al-Mn transition edge sensor (TES) bolometers is studied as we vary the engineered TES transition, heat capacity, and/or coupling between the heat capacity and TES. We present thermal structure measurements of each of the 39 designs tested. The data is accurately fit by a two-body bolometer model, which allows us to extract the basic TES parameters that affect device stability. We conclude that parameters affecting device stability can be engineered for optimal device operation, and present the model parameters extracted for the different TES designs. [ABSTRACT FROM AUTHOR]

We present a measurement of the angular bispectrum of the millimeter-wave sky in observing bands centered at roughly 95, 150, and 220 GHz, on angular scales of 1′ ≲ θ ≲ 10′ (multipole number 1000 ≲ l ≲ 10,000). At these frequencies and angular scales, the main contributions to the bispectrum are expected to be the thermal Sunyaev-Zel'dovich (tSZ) effect and emission from extragalactic sources, predominantly dusty, star-forming galaxies (DSFGs) and active galactic nuclei. We measure the bispectrum in 800 deg2 of three-band South Pole Telescope data, and we use a multi-frequency fitting procedure to separate the bispectrum of the tSZ effect from the extragalactic source contribution. We simultaneously detect the bispectrum of the tSZ effect at >10σ, the unclustered component of the extragalactic source bispectrum at >5σ in each frequency band, and the bispectrum due to the clustering of DSFGs—i.e., the clustered cosmic infrared background (CIB) bispectrum—at >5σ. This is the first reported detection of the clustered CIB bispectrum. We use the measured tSZ bispectrum amplitude, compared to model predictions, to constrain the normalization of the matter power spectrum to be σ8 = 0.787 ± 0.031 and to predict the amplitude of the tSZ power spectrum at l = 3000. This prediction improves our ability to separate the thermal and kinematic contributions to the total SZ power spectrum. The addition of bispectrum data improves our constraint on the tSZ power spectrum amplitude by a factor of two compared to power spectrum measurements alone and demonstrates a preference for a nonzero kinematic SZ (kSZ) power spectrum, with a derived constraint on the kSZ amplitude at l = 3000 of AkSZ = 2.9 ± 1.6 μK2, or AkSZ = 2.6 ± 1.8 μK2 if the default AkSZ > 0 prior is removed. [ABSTRACT FROM AUTHOR]

We explore extensions to the ΛCDM cosmology using measurements of the cosmic microwave background (CMB) from the recent SPT-SZ survey, along with data from WMAP7 and measurements of H0 and baryon acoustic oscillation (BAO). We check for consistency within ΛCDM between these data sets, and find some tension. The CMB alone gives weak support to physics beyond ΛCDM, due to a slight trend relative to ΛCDM of decreasing power toward smaller angular scales. While it may be due to statistical fluctuation, this trend could also be explained by several extensions. We consider running of the primordial spectral index (dns/dln k), as well as two extensions that modify the damping tail power (the primordial helium abundance Yp and the effective number of neutrino species Neff) and one that modifies the large-scale power due to the integrated Sachs-Wolfe effect (the sum of neutrino masses ∑mν). These extensions have similar observational consequences and are partially degenerate when considered simultaneously. Of the six one-parameter extensions considered, we find CMB to have the largest preference for dns/dln k with –0.046 < dns/dln k < –0.003 at 95% confidence, which strengthens to a 2.7σ indication of dns/dln k < 0 from CMB+BAO+H0. Detectable dns/dln k ≠ 0 is difficult to explain in the context of single-field, slow-roll inflation models. We find Neff = 3.62 ± 0.48 for the CMB, which tightens to Neff = 3.71 ± 0.35 from CMB+BAO+H0. Larger values of Neff relieve the mild tension between CMB, BAO, and H0. When the Sunyaev-Zel'dovich selected galaxy cluster abundances () data are also included, we obtain Neff = 3.29 ± 0.31. Allowing for ∑mν gives a 3.0σ detection of ∑mν > 0 from CMB+BAO+H0 +. The median value is (0.32 ± 0.11) eV, a factor of six above the lower bound set by neutrino oscillation observations. All data sets except H0 show some preference for massive neutrinos; data combinations including H0 favor nonzero masses only if BAO data are also included. We also constrain the two-parameter extensions Neff + ∑mν and Neff + Yp to explore constraints on additional light species and big bang nucleosynthesis, respectively. [ABSTRACT FROM AUTHOR]

We present a measurement of the cosmic microwave background (CMB) temperature power spectrum using data from the recently completed South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey. This measurement is made from observations of 2540 deg2 of sky with arcminute resolution at 150 GHz, and improves upon previous measurements using the SPT by tripling the sky area. We report CMB temperature anisotropy power over the multipole range 650 < ℓ < 3000. We fit the SPT bandpowers, combined with the 7 yr Wilkinson Microwave Anisotropy Probe (WMAP7) data, with a six-parameter ΛCDM cosmological model and find that the two datasets are consistent and well fit by the model. Adding SPT measurements significantly improves ΛCDM parameter constraints; in particular, the constraint on θs tightens by a factor of 2.7. The impact of gravitational lensing is detected at 8.1σ, the most significant detection to date. This sensitivity of the SPT+WMAP7 data to lensing by large-scale structure at low redshifts allows us to constrain the mean curvature of the observable universe with CMB data alone to be . Using the SPT+WMAP7 data, we measure the spectral index of scalar fluctuations to be ns = 0.9623 ± 0.0097 in the ΛCDM model, a 3.9σ preference for a scale-dependent spectrum with ns < 1. The SPT measurement of the CMB damping tail helps break the degeneracy that exists between the tensor-to-scalar ratio r and ns in large-scale CMB measurements, leading to an upper limit of r < 0.18 (95% C.L.) in the ΛCDM+r model. Adding low-redshift measurements of the Hubble constant (H0) and the baryon acoustic oscillation (BAO) feature to the SPT+WMAP7 data leads to further improvements. The combination of SPT+WMAP7+H0+BAO constrains ns = 0.9538 ± 0.0081 in the ΛCDM model, a 5.7σ detection of ns < 1, and places an upper limit of r < 0.11 (95% C.L.) in the ΛCDM+r model. These new constraints on ns and r have significant implications for our understanding of inflation, which we discuss in the context of selected single-field inflation models. [ABSTRACT FROM AUTHOR]

We present a point-source catalog from 771 deg2 of the South Pole Telescope Sunyaev-Zel'dovich survey at 95, 150, and 220 GHz. We detect 1545 sources above 4.5σ significance in at least one band. Based on their relative brightness between survey bands, we classify the sources into two populations, one dominated by synchrotron emission from active galactic nuclei, and one dominated by thermal emission from dust-enshrouded star-forming galaxies. We find 1238 synchrotron and 307 dusty sources. We cross-match all sources against external catalogs and find 189 unidentified synchrotron sources and 189 unidentified dusty sources. The dusty sources without counterparts are good candidates for high-redshift, strongly lensed submillimeter galaxies. We derive number counts for each population from 1 Jy down to roughly 11, 4, and 11 mJy at 95, 150, and 220 GHz. We compare these counts with galaxy population models and find that none of the models we consider for either population provide a good fit to the measured counts in all three bands. The disparities imply that these measurements will be an important input to the next generation of millimeter-wave extragalactic source population models. [ABSTRACT FROM AUTHOR]

Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This "B-mode" signal provides a measure of the projected mass distribution over the entire observable Universe and also acts as a contaminant for the measurement of primordial gravity-wave signals. In this Letter we present the first detection of gravitational lensing B modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing B-mode signal by combining E-mode polarization measured by SPTpol with estimates of the lensing potential from a Herschel-SPIRE map of the cosmic infrared background. We compare this template to the B modes measured directly by SPTpol, finding a nonzero correlation at 7.7s significance. The correlation has an amplitude and scale dependence consistent with theoretical expectations, is robust with respect to analysis choices, and constitutes the first measurement of a powerful cosmological observable. [ABSTRACT FROM AUTHOR]

We present first results on the cooling properties derived from Chandra X-ray observations of 83 high-redshift (0.3 < z < 1.2) massive galaxy clusters selected by their Sunyaev-Zel'dovich signature in the South Pole Telescope data. We measure each cluster's central cooling time, central entropy, and mass deposition rate, and compare these properties to those for local cluster samples. We find no significant evolution from z ~ 0 to z ~ 1 in the distribution of these properties, suggesting that cooling in cluster cores is stable over long periods of time. We also find that the average cool core entropy profile in the inner ~100 kpc has not changed dramatically since z ~ 1, implying that feedback must be providing nearly constant energy injection to maintain the observed ?entropy floor? at ~10 keV cm2. While the cooling properties appear roughly constant over long periods of time, we observe strong evolution in the gas density profile, with the normalized central density (ρg,0/ρcrit) increasing by an order of magnitude from z ~ 1 to z ~ 0. When using metrics defined by the inner surface brightness profile of clusters, we find an apparent lack of classical, cuspy, cool-core clusters at z > 0.75, consistent with earlier reports for clusters at z > 0.5 using similar definitions. Our measurements indicate that cool cores have been steadily growing over the 8 Gyr spanned by our sample, consistent with a constant, ~150Mʘ yr-1 cooling flow that is unable to cool below entropies of 10 keV cm2 and, instead, accumulates in the cluster center. We estimate that cool cores began to assemble in these massive systems at zcool = 1.0+1.0-0.2, which represents the first constraints on the onset of cooling in galaxy cluster cores. At high redshift (z ≳ 0.75), galaxy clusters may be classified as "cooling flows" (low central entropy, cooling time) but not "cool cores" (cuspy surface brightness profile), meaning that care must be taken when classifying these high-z systems. We investigate several potential biases that could conspire to mimic this cool core evolution and are unable to find a bias that has a similar redshift dependence and a substantial amplitude. [ABSTRACT FROM AUTHOR]

The spectral density SΦ(f)=A2/(f/1 Hz)α of magnetic flux noise in ten dc superconducting quantum interference devices (SQUIDs) with systematically varied geometries shows that a increases as the temperature is lowered; in so doing, each spectrum pivots about a nearly constant frequency. The mean-square flux noise, inferred by integrating the power spectra, grows rapidly with temperature and at a given temperature is approximately independent of the outer dimension of a given SQUID. These results are incompatible with a model based on the random reversal of independent, surface spins. [ABSTRACT FROM AUTHOR]

In the cores of some clusters of galaxies the hot intracluster plasma is dense enough that it should cool radiatively in the cluster's lifetime, leading to continuous 'cooling flows' of gas sinking towards the cluster centre, yet no such cooling flow has been observed. The low observed star-formation rates and cool gas masses for these 'cool-core' clusters suggest that much of the cooling must be offset by feedback to prevent the formation of a runaway cooling flow. Here we report X-ray, optical and infrared observations of the galaxy cluster SPT-CLJ2344-4243 (ref. 11) at redshift z = 0.596. These observations reveal an exceptionally luminous (8.2?×?1045?erg?s?1) galaxy cluster that hosts an extremely strong cooling flow (around 3,820 solar masses a year). Further, the central galaxy in this cluster appears to be experiencing a massive starburst (formation of around 740 solar masses a year), which suggests that the feedback source responsible for preventing runaway cooling in nearby cool-core clusters may not yet be fully established in SPT-CLJ2344-4243. This large star-formation rate implies that a significant fraction of the stars in the central galaxy of this cluster may form through accretion of the intracluster medium, rather than (as is currently thought) assembling entirely via mergers. [ABSTRACT FROM AUTHOR]

Aim Brain metastasis is infrequent in colorectal cancer patients, and the prognosis is poor. In this retrospective study survival and prognostic factors were determined in patients with brain metastasis from colorectal cancer. Method Between 1997 and 2006, 39 patients with brain metastasis from colorectal cancer who survived more than 1 month were identified. Data were collected with regard to patient characteristics, location and stage of the primary tumour, extent and location of metastatic disease, and treatment modalities used. Results Most (79.5%) patients had pulmonary metastases before brain metastasis, and the brain was the site of solitary metastasis in only one patient. The most frequent symptom was weakness [18 (43.6%) patients]. Overall median survival was 5.0 months and the 1- and 2-year survival rates were 21.8 and 9.1%, respectively. Univariate analysis revealed uncontrolled extracranial metastases ( P = 0.019), multiple brain lesions ( P = 0.026), bilateral brain metastases ( P = 0.032) and serum carcinoembryonic antigen levels greater than 5 ng/ml ( P = 0.008) to be poor prognostic factors. The median survival after the diagnosis of brain metastasis was significantly longer in patients who underwent surgical resection (15.2 ± 8.0 months) than in those treated by other modalities ( P = 0.001). Treatment modality was the only independent prognostic factor for overall survival in patients with brain metastases from colorectal cancers ( P = 0.015). Conclusion Aggressive surgical resection in selected patients with brain metastases from colorectal cancer may prolong survival, even in the presence of extracranial metastatic lesions. [ABSTRACT FROM AUTHOR]

Maximizing the sensitivity of balloon-based and space-based observations of the cosmic microwave background (CMB) requires detectors with substantially lower saturation power and background noise than ground-based observations, because of reduced atmospheric loading and lower photon noise. We have fabricated and tested prototype transition-edge sensor (TES) bolometers that have architecture identical to that used in feedhorn-coupled TES polarimeter arrays developed for ground-based CMB observations, but have saturation power appropriate for balloon-based or space-based observations (0.5 pW-7 pW). The operating resistance of these bolometers (∼3 mΩ) is appropriate for readout with time-division or gigahertz frequency-division SQUID multiplexers. Dark bolometer measurements show that the noise levels are near the expected thermal-fluctuation-noise background (<10 W/Hz), that the thermal response times are faster than the observation requirements, and that low-frequency 1/ f noise can be strongly suppressed to <10 mHz by pair differencing. We report on the performance of the prototype devices and progress towards optimizing them for balloon-based and spaced-based observations. [ABSTRACT FROM AUTHOR]

The Atacama pathfinder experiment Sunyaev-Zel'dovich (APEX-SZ) instrument is a millimeter-wave cryogenic receiver designed to observe galaxy clusters via the Sunyaev-Zel'dovich effect from the 12 m APEX telescope on the Atacama plateau in Chile. The receiver contains a focal plane of 280 superconducting transition-edge sensor (TES) bolometers instrumented with a frequency-domain multiplexed readout system. The bolometers are cooled to 280 mK via a three-stage helium sorption refrigerator and a mechanical pulse-tube cooler. Three warm mirrors, two 4 K lenses, and a horn array couple the TES bolometers to the telescope. APEX-SZ observes in a single frequency band at 150 GHz with 1′ angular resolution and a 22′ field-of-view, all well suited for cluster mapping. The APEX-SZ receiver has played a key role in the introduction of several new technologies including TES bolometers, the frequency-domain multiplexed readout, and the use of a pulse-tube cooler with bolometers. As a result of these new technologies, the instrument has a higher instantaneous sensitivity and covers a larger field-of-view than earlier generations of Sunyaev-Zel'dovich instruments. The TES bolometers have a median sensitivity of 890 [formula] (NEy of 3.5 × 10-4 [formula]). We have also demonstrated upgraded detectors with improved sensitivity of 530 [formula] (NEy of 2.2 × 10-4 [formula]). Since its commissioning in April 2007, APEX-SZ has been used to map 48 clusters. We describe the design of the receiver and its performance when installed on the APEX telescope. [ABSTRACT FROM AUTHOR]