Superconducting subterahertz fast nanoswitch

A superconducting thin-film nanoswitch for the subterahertz frequency range has been proposed, developed, fabricated, and tested. The switch makes it possible to modulate the microwave signal or switch it between two branches of a circuit with low losses and high speed. The switch can be naturally integrated with superconducting high-sensitive detectors. Its application makes it possible to avoid the use of massive slow mechanical modulators and to improve the measurement accuracy in decisive astrophysical experiments such as the investigation of the anisotropy of the cosmic microwave background

Mexico-UK Sub-millimeter Camera for AsTronomy

MUSCAT is a large format mm-wave camera scheduled for installation on the Large Millimeter Telescope Alfonso Serrano (LMT) in 2018. The MUSCAT focal plane is based on an array of horn coupled lumped-element kinetic inductance detectors optimised for coupling to the 1.1mm atmospheric window. The detectors are fed with fully baffled reflective optics to minimize stray-light contamination. This combination will enable background-limited performance at 1.1 mm across the full 4 arcminute field-of-view of the LMT. The easily accessible focal plane will be cooled to 100 mK with a new closed cycle miniature dilution refrigerator that permits fully continuous operation. The MUSCAT instrument will demonstrate the science capabilities of the LMT through two relatively short science programmes to provide high resolution follow-up surveys of Galactic and extra-galactic sources previously observed with the Herschel space observatory, after the initial observing campaigns. In this paper, we will provide an overview of the overall instrument design as well as an update on progress and scheduled installation on the LMT.Comment: Accepted for publication in the Journal of Low Temperature Detector

Photon-noise limited sensitivity in titanium nitride kinetic inductance detectors

We demonstrate photon-noise limited performance at sub-millimeter wavelengths in feedhorn-coupled, microwave kinetic inductance detectors (MKIDs) 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~\micron. 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$\times 10^{-17}$ W/$\sqrt{\mathrm{Hz}}$. This sensitivity makes these devices suitable for broadband photometric applications at these wavelengths

A Multi-wavelength Study of the Sunyaev-Zel'dovich Effect in the Triple-Merger Cluster MACS J0717.5+3745 with MUSTANG and Bolocam

We present 90, 140, and 268GHz sub-arcminute resolution imaging of the Sunyaev-Zel'dovich effect (SZE) in MACSJ0717.5+3745. Our 90GHz SZE data result in a sensitive, 34uJy/bm map at 13" resolution using MUSTANG. Our 140 and 268GHz SZE imaging, with resolutions of 58" and 31" and sensitivities of 1.8 and 3.3mJy/beam respectively, was obtained using Bolocam. We compare these maps to a 2-dimensional pressure map derived from Chandra X-ray observations. Our MUSTANG data confirm previous indications from Chandra of a pressure enhancement due to shock-heated, >20keV gas immediately adjacent to extended radio emission seen in low-frequency radio maps. The MUSTANG data also detect pressure substructure that is not well-constrained by the X-ray data in the remnant core of a merging subcluster. We find that the small-scale pressure enhancements in the MUSTANG data amount to ~2% of the total pressure measured in the 140GHz Bolocam observations. The X-ray template also fails on larger scales to accurately describe the Bolocam data, particularly at the location of a subcluster known to have a high line of sight optical velocity (~3200km/s). Our Bolocam data are adequately described when we add an additional component - not described by a thermal SZE spectrum - coincident with this subcluster. Using flux densities extracted from our model fits, and marginalizing over the temperature constraints for the region, we fit a thermal+kinetic SZE spectrum to our data and find the subcluster has a best-fit line of sight proper velocity of 3600+3440/-2160km/s. This agrees with the optical velocity estimates for the subcluster. The probability of velocity<0 given our measurements is 2.1%. Repeating this analysis using flux densities measured non-parametrically results in a 3.4% probability of a velocity<=0. We note that this tantalizing result for the kinetic SZE is on resolved, subcluster scales.Comment: 10 Figures, 18 pages. this version corrects issues with the previous arXiv versio

BLAST: The Mass Function, Lifetimes, and Properties of Intermediate Mass Cores from a 50 Square Degree Submillimeter Galactic Survey in Vela (l = ~265)

We present first results from an unbiased 50 deg^2 submillimeter Galactic survey at 250, 350, and 500 micron from the 2006 flight of the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). The map has resolution ranging from 36 arcsec to 60 arcsec in the three submillimeter bands spanning the thermal emission peak of cold starless cores. We determine the temperature, luminosity, and mass of more than one thousand compact sources in a range of evolutionary stages and an unbiased statistical characterization of the population. From comparison with C^(18)O data, we find the dust opacity per gas mass, kappa r = 0.16 cm^2 g^(-1) at 250 micron, for cold clumps. We find that 2% of the mass of the molecular gas over this diverse region is in cores colder than 14 K, and that the mass function for these cold cores is consistent with a power law with index alpha = -3.22 +/- 0.14 over the mass range 14 M_sun < M < 80 M_sun. Additionally, we infer a mass-dependent cold core lifetime of t_c(M) = 4E6 (M/20 M_sun)^(-0.9) years - longer than what has been found in previous surveys of either low or high mass cores, and significantly longer than free fall or likely turbulent decay times. This implies some form of non-thermal support for cold cores during this early stage of star formation.Comment: Accepted for publication in the Astrophysical Journal. Maps available at http://blastexperiment.info

SPHEREx: NASA's near-infrared spectrophotometric all-sky survey

SPHEREx, the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and ices Explorer, is a NASA MIDEX mission planned for launch in 2024. SPHEREx will carry out the first all-sky spectral survey at wavelengths between 0.75µm and 5µm with spectral resolving power ~40 between 0.75 and 3.8µm and ~120 between 3.8 and 5µm At the end of its two-year mission, SPHEREx will provide 0.75-to-5µm spectra of each 6.”2 x 6.”2 pixel on the sky - 14 billion spectra in all. This paper updates an earlier description of SPHEREx presenting changes made during the mission's Preliminary Design Phase, including a discussion of instrument integration and test ow and a summary of the data processing, analysis, and distribution plans

153. Superconducting Cold-Electron Bolometer with JFET Readout for OLIMPO Balloon Telescope

The OLIMPO experiment is a large balloon-borne telescope, aimed at measuring the Sunyaev-Zeldovich effect in many clusters of Galaxies. OLIMPO will carry out its surveys in four frequency bands centered at 140, 220, 410 and 540 GHz. The detector system is made of four bolometer arrays. In order to achieve low dispersion in the characteristics of the detectors, a fully photo-lithographic process producing sensors on silicon nitride islands or plane Si substrate should be developed. Filters and antennas can be integrated on the detectors wafer by means of micro-strip technology. Attractive variant is to use Capacitively Coupled Cold-Electron Bolometers (CEB) with JFET readout. The JFET readout has been developed already for the BOOMERanG and Planck-HFI. The problem is to match relatively low-ohmic dynamic resistance of CEB ( 1kOhm) and high noise equivalent resistance of JFET ( 1 MOhm).The goal is to achieve level of noise-equivalen power (NEP) of CEB less than photon noise. Analysis of a single CEB with JFET readout has not given positive results in both current-biased and voltage-biased modes. Current fluctuations of JFET and feedback resistor are rather low. The main reason of fail is strong influence of voltage noise. The voltage is divided by small dynamic resistance of the junctions in cooling region (voltage-biased mode) and gives strong current noise. Any attempts to increase dynamic resistance moving to smaller voltages led to strong decrease of cooling and degradation of responsivity.To achieve noise matching with JFET, a Cold-Electron Bolometer with a weak Superconducting Absorber (SCEB) has been proposed. In this case we can operate in voltage-biased mode with voltage in the range between (Delta 1-Delta 2) and (Delta1 + Delta 2). In this region the IV of SIS\ub4 junctions is rather flat with considerably increased dynamic resistance up to the level of Rj=1000*Rn (typical level of leakage). Electron cooling will be still very effective for incoming power. Simulations show that we can achieve photon noise level for structure with Ti absorber and Al/Ti tunnel junctions (Al antenna electrode) for all frequency ranges with estimated power load

153. Superconducting Cold-Electron Bolometer with JFET Readout for OLIMPO Balloon Telescope

The OLIMPO experiment is a large balloon-borne telescope, aimed at measuring the Sunyaev-Zeldovich effect in many clusters of Galaxies. OLIMPO will carry out its surveys in four frequency bands centered at 140, 220, 410 and 540 GHz. The detector system is made of four bolometer arrays. In order to achieve low dispersion in the characteristics of the detectors, a fully photo-lithographic process producing sensors on silicon nitride islands or plane Si substrate should be developed. Filters and antennas can be integrated on the detectors wafer by means of micro-strip technology. Attractive variant is to use Capacitively Coupled Cold-Electron Bolometers (CEB) with JFET readout. The JFET readout has been developed already for the BOOMERanG and Planck-HFI. The problem is to match relatively low-ohmic dynamic resistance of CEB ( 1kOhm) and high noise equivalent resistance of JFET ( 1 MOhm).The goal is to achieve level of noise-equivalen power (NEP) of CEB less than photon noise. Analysis of a single CEB with JFET readout has not given positive results in both current-biased and voltage-biased modes. Current fluctuations of JFET and feedback resistor are rather low. The main reason of fail is strong influence of voltage noise. The voltage is divided by small dynamic resistance of the junctions in cooling region (voltage-biased mode) and gives strong current noise. Any attempts to increase dynamic resistance moving to smaller voltages led to strong decrease of cooling and degradation of responsivity.To achieve noise matching with JFET, a Cold-Electron Bolometer with a weak Superconducting Absorber (SCEB) has been proposed. In this case we can operate in voltage-biased mode with voltage in the range between (Delta 1-Delta 2) and (Delta1 + Delta 2). In this region the IV of SIS\ub4 junctions is rather flat with considerably increased dynamic resistance up to the level of Rj=1000*Rn (typical level of leakage). Electron cooling will be still very effective for incoming power. Simulations show that we can achieve photon noise level for structure with Ti absorber and Al/Ti tunnel junctions (Al antenna electrode) for all frequency ranges with estimated power load

Superconducting Cold-Electron Bolometer with JFET Readout for OLIMPO Balloon Telescope

The OLIMPO experiment is a 2.6 m balloon-borne telescope, aimed at measuring the Sunyaev- Zeldovich effect in clusters of Galaxies. OLIMPO will carry out surveys in four frequency bands centered at 140, 220, 410 and 540 GHz. The detector system consists of four bolometer arrays and incorporates new detector technologies that are potential candidates for future space missions. One of these technologies is the Capacitively Coupled Cold-Electron Bolometer (CEB) with JFET readout. The JFET readout coupled to semiconductor-based high-impedence bolometers has been developed already for the BOOMERanG and Planck-HFI experiments. The CEB is a planar antenna-coupled superconductong detector with high sensitivity and high dynamic range. Here, we discuss a scheme to match the relatively moderate dynamic resistance of CEB (~1kOhm) to the high noise equivalent resistance of JFET (1 MΩ). To achieve noise matching with JFET, a Cold-Electron Bolometer with a weak Superconducting Absorber (SCEB) has been proposed. In voltage-biased mode with voltage higher than (Delta 1-Delta 2) the IV of SIS\u27 junctions has considerably increased dynamic resistance up to the level of Rj = 1000*Rn. Electron cooling will be still very effective for the incoming power. Simulations show that photon noise level can be achieved at 300 mK for a structure with Ti absorber and Al/Ti tunnel junctions for all frequency ranges with the estimated in-flight optical power load for OLIMPO

Superconducting Cold-Electron Bolometer with JFET Readout for OLIMPO Balloon Telescope

The OLIMPO experiment is a 2.6 m balloon-borne telescope, aimed at measuring the Sunyaev- Zeldovich effect in clusters of Galaxies. OLIMPO will carry out surveys in four frequency bands centered at 140, 220, 410 and 540 GHz. The detector system consists of four bolometer arrays and incorporates new detector technologies that are potential candidates for future space missions. One of these technologies is the Capacitively Coupled Cold-Electron Bolometer (CEB) with JFET readout. The JFET readout coupled to semiconductor-based high-impedence bolometers has been developed already for the BOOMERanG and Planck-HFI experiments. The CEB is a planar antenna-coupled superconductong detector with high sensitivity and high dynamic range. Here, we discuss a scheme to match the relatively moderate dynamic resistance of CEB (~1kOhm) to the high noise equivalent resistance of JFET (1 MΩ). To achieve noise matching with JFET, a Cold-Electron Bolometer with a weak Superconducting Absorber (SCEB) has been proposed. In voltage-biased mode with voltage higher than (Delta 1-Delta 2) the IV of SIS\u27 junctions has considerably increased dynamic resistance up to the level of Rj = 1000*Rn. Electron cooling will be still very effective for the incoming power. Simulations show that photon noise level can be achieved at 300 mK for a structure with Ti absorber and Al/Ti tunnel junctions for all frequency ranges with the estimated in-flight optical power load for OLIMPO