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The South Pole Telescope (SPT) is a 10 m diameter, wide-field, offset Gregorian telescope with a 966 pixel, multicolor, millimeter-wave, bolometer camera. It is located at the Amundsen-Scott South Pole station in Antarctica. The design of the SPT emphasizes careful control of spillover and scattering, to minimize noise and false signals due to ground pickup. The key initial project is a large-area survey at wavelengths of 3, 2, and 1.3 mm, to detect clusters of galaxies via the Sunyaev-Zel’dovich effect and to measure the small-scale angular power spectrum of the cosmic microwave background (CMB). The data will be used to characterize the primordial matter power spectrum and to place constraints on the equation of state of dark energy. A second-generation camera will measure the polarization of the CMB, potentially leading to constraints on the neutrino mass and the energy scale of inflation.

X-ray, optical and infrared observations reveal a very high rate of star formation in the core of an extremely luminous galaxy cluster; this starburst seems to be triggered by a cooling flow of the dense intracluster plasma. A cool-running galaxy cluster Theory predicts that the hot intracluster plasma in the cores of some galaxy clusters is dense enough to cool radiatively during the cluster's lifetime. This should lead to continuous 'cooling flows' of gas sinking towards the cluster centre, yet until now no substantial cooling flow had been observed. New optical and X-ray observations of the galaxy cluster SPT-CLJ2344-424316 at z = 0.596 reveal it to be exceptionally luminous, with a remarkably strong cooling flow equivalent to more than 3,000 solar masses per year. The central galaxy of the cluster appears to be experiencing a massive starburst, which suggests that the feedback source thought to be responsible for preventing runaway cooling in nearby cool-core clusters is not yet established in this cluster. 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 1 , 2 , 3 , 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 4 , 5 and cool gas masses 6 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 7 , 8 , 9 , 10 . 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 × 10 45  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.

We have developed a new transition-edge sensor material with critical temperature ( T c ) in the range 100–200 mK. The new material is a solid solution of two superconducting components, Mo x Nb 1− x , co-sputtered from two high-purity single-component targets (Mo and Nb). The T c has a minimum (d T c / d x  = 0) at an intermediate concentration of the components. We have optimized the deposition parameters and composition to provide films with a sharp superconducting transition at ~ 150 mK. We investigated structural features of the films and surface morphology using X-ray diffraction (XRD) and scanning electron microscopy. The XRD measurements indicate that the grown films are polycrystalline, with a preferred orientation along the (110) crystal direction and a clear correlation between superconducting properties and film microstructure.

SuperSpec is an ultra-compact spectrometer-on-a-chip for mm and submm wavelength astronomy. Its very small size, wide spectral bandwidth, and highly multiplexed detector readout will enable construction of powerful multi-object spectrometers for observations of galaxies at high redshift. SuperSpec is a filter bank with planar, lithographed, superconducting transmission line resonator filters and lumped-element kinetic inductance detectors made from Titanium Nitride. We have built an 81 detector prototype that operates in the 195–310 GHz band. The prototype has a wide-band metal feed horn with a transition to microstrip that feeds the filter bank. The prototype has demonstrated optical filter bank channels with a range of resolving powers from 300 to 700, measured fractional frequency noise of 10 - 17 Hz - 1 at 1 Hz.

SuperSpec is a novel on-chip spectrometer we are developing for (sub)millimeter wavelength astronomy. Our approach utilizes a filterbank of moderate resolution ( R ∼ 500 ) channels, coupled to lumped element kinetic inductance detectors (KIDs), all integrated onto a single silicon chip. The channels are half-wave resonators formed by lithographically depositing segments of superconducting transmission line, and the KIDs are titanium nitride resonators. Here we present optical measurements of a first generation prototype, operating in the 180–280 GHz frequency range. We have used a coherent source to measure the spectral profiles of 17 channels, which achieve linewidths corresponding to quality factors as high as Q filt = 700 , consistent with the designed values plus additional dissipation characterized by Q i ≈ 1440 . We have also used a Fourier Transform Spectrometer to characterize the spectral purity of all 72 channels on the chip, and measure typical out of band responses ∼ 30 dB below the peak response.

Frequency-domain multiplexing is a readout technique for transition-edge sensor bolometer arrays used on modern cosmic microwave background experiments, including the SPT-3G receiver. Here, we present design details and performance measurements for a low-parasitic frequency-domain multiplexing readout. Reducing the parasitic impedance of the connections between cryogenic components provides a path to improve both the crosstalk and noise performance of the readout. Reduced crosstalk will in turn allow higher-multiplexing factors. We have demonstrated a factor of two improvement in parasitic resistance compared to SPT-3G hardware. Reduced parasitics also permits operation of lower-resistance bolometers optimized for improved readout noise performance. We demonstrate that a module in the prototype system has comparable readout noise performance to an SPT-3G module when operated with dark TES bolometers in the laboratory.

We propose a multiplexible kinetic inductance ammeter, which uses a high-quality-factor, superconducting, lumped-element, kinetic inductance resonator as a current sensor, a short, superconducting coplanar waveguide (CPW) for current input, and a CPW transmission line for the sensor readout. The resonator consists of an interdigitated capacitor and a superconducting loop that inductively couples to the input CPW. Current running through the central line of the input CPW generates magnetic fields which are focused into the gaps of the input CPW. These magnetic fields can be measured collectively as the magnetic flux through the superconducting loop. The kinetic inductance of the superconducting loop depends on the screening current for the magnetic flux, so the input current is converted to a change in the frequency of the resonator. We analyze the response and noise of a kinetic inductance ammeter with a high-resistivity NbN loop.

SuperSpec is a novel on-chip spectrometer we are developing for multi-object, moderate resolution ( R = 100–500), large bandwidth ( ∼ 1.65 : 1 ), submillimeter and millimeter survey spectroscopy of high-redshift galaxies. The spectrometer employs a filter bank architecture, and consists of a series of half-wave resonators formed by lithographically-patterned superconducting transmission lines. The signal power admitted by each resonator is detected by a lumped element titanium nitride (TiN) kinetic inductance detector operating at 100–200 MHz. We have tested a new prototype device that achieves the targeted R = 100 resolving power, and has better detector sensitivity and optical efficiency than previous devices. We employ a new method for measuring photon noise using both coherent and thermal sources of radiation to cleanly separate the contributions of shot and wave noise. We report an upper limit to the detector NEP of 1.4 × 10 - 17 W Hz - 1 / 2 , within 10 % of the photon noise-limited NEP for a ground-based R = 100 spectrometer.

Polarization observations of the cosmic microwave background with the Cosmic Background Imager from September 2002 to May 2004 provide a significant detection of the f-mode polarization and reveal an angular power spectrum of polarized emission showing peaks and valleys that are shifted in phase by half a cycle relative to those of the total intensity spectrum. This key agreement between the phase of the observed polarization spectrum and that predicted on the basis of the total intensity spectrum provides support for the standard model of cosmology, in which dark matter and dark energy are the dominant constituents, the geometry is close to flat, and primordial density fluctuations are predominantly adiabatic with a matter power spectrum commensurate with inflationary cosmological models.

Background Basic trainees in the US military have historically been vulnerable to respiratory infections. Adenovirus and influenza are the most common etiological agents responsible for febrile respiratory illness (FRI) among trainees and present with similar clinical signs and symptoms. Identifying demographic and clinical factors associated with the primary viral pathogens causing FRI epidemics among trainees will help improve differential diagnosis and allow for appropriate distribution of antiviral medications. The objective of this study was to determine what demographic and clinical factors are associated with influenza and adenovirus among military trainees. Methods Specimens were systematically collected from military trainees meeting FRI case definition (fever ≥38.0°C with either cough or sore throat; or provider-diagnosed pneumonia) at eight basic training centers in the USA. PCR and/or cell culture testing for respiratory pathogens were performed on specimens. Interviewer-administered questionnaires collected information on patient demographic and clinical factors. Polychotomous logistic regression was employed to assess the association between these factors and FRI outcome categories: laboratory-confirmed adenovirus, influenza, or other FRI. Sensitivity, specificity, positive and negative predictive value were calculated for individual predictors and clinical combinations of predictors. Results Among 21,570 FRI cases sampled between 2004 and 2009, 63.6% were laboratory-confirmed adenovirus cases and 6.6% were laboratory-confirmed influenza cases. Subjects were predominantly young men (86.8% men; mean age 20.8 ± 3.8 years) from Fort Jackson (18.8%), Great Lakes (17.1%), Fort Leonard Wood (16.3%), Marine Corps Recruit Depot (MCRD) San Diego (19.0%), Fort Benning (13.3%), Lackland (7.5%), MCRD Parris Island (8.7%), and Cape May (3.2%). The best multivariate predictors of adenovirus were the combination of sore throat (odds ratio [OR], 2.94; 95% confidence interval [CI], 2.66-3.25), cough (OR, 2.33; 95% CI, 2.11-2.57), and fever (OR, 2.07; 95% CI, 1.90-2.26) with a PPV of 77% (p ≤.05). A combination of cough, fever, training week 0-2 and acute onset were most predictive of influenza (PPV =38%; p ≤ .05). Conclusions Specific demographic and clinical factors were associated with laboratory-confirmed influenza and adenovirus among military trainees. Findings from this study can guide clinicians in the diagnosis and treatment of military trainees presenting with FRI.