Explore the vast range of titles available.

We developed a simple add-on, cryogen-free, and low-power consumption calibrator for a new transition-edge sensor (TES) bolometer camera mounted on the ASTE 10-m telescope. To measure the responsivity of the TES bolometers and accurately correct for the nonlinearity and atmospheric extinction, we designed a motor-driven rotating filter wheel system installed in front of the cryostat window. This calibrator is required to cover the loading power under various atmospheric conditions, which corresponds to precipitable water vapor (PWV) of 0.5–4 mm. For this range of PWV, 25–100 K blackbodies are necessary for the observing bands of 1.1 and 0.85 mm. To simulate the temperature range, bolometers in the cryostat are also optically coupled to the low-temperature stage ( < 4  K) inside the cryostat by spherical mirrors. In addition, we used moderately absorptive polystyrene plates that are placed between a spherical mirror and the cryostat window. Various combinations of filters result in eight different temperatures by the filter wheel system and simulate the atmospheric emission under various weather conditions at the ASTE site.

We developed and deployed a simple add-on multi-temperature calibrator for our multicolor transition edge sensor (TES) bolometer camera aimed at simultaneous observation with observing wavelengths of 1.1 and 0.85 mm. To cover the power loading level from the atmospheric emission corresponding to precipitable water vapor (PWV) of 0.5–4 mm, the calibrator consists of spherical mirrors to show the low-temperature stages of the cryostat and filters with moderate opacity to mimic the eight-temperature cold blackbodies. The loading powers introduced by each filter were self-calibrated by measuring the load curves of the TES bolometers when a filter was placed in front of the cryostat window. Each science observation was preceded by the calibration process, which measures the response of the TES bolometers to the atmosphere and filters of various opacities. Then, the responsivities of TES bolometers were derived to convert their output signal to the loading power and correct for the nonlinearity inherent in its response. Furthermore, the loading power falling on the TES bolometers from atmospheric emission measured at various PWV was in good correlation with the PWV measured with the radiometer, which enables the atmospheric extinction correction by fast and sensitive bolometers compared to the available radiometers with the modest sampling speeds.

Ultra-wideband, three-dimensional (3D) imaging spectrometry in the millimeter–submillimeter (mm–submm) band is an essential tool for uncovering the dust-enshrouded portion of the cosmic history of star formation and galaxy evolution1–3. However, it is challenging to scale up conventional coherent heterodyne receivers4 or free-space diffraction techniques5 to sufficient bandwidths (≥1 octave) and numbers of spatial pixels2,3 (>102). Here, we present the design and astronomical spectra of an intrinsically scalable, integrated superconducting spectrometer6, which covers 332–377 GHz with a spectral resolution of F/ΔF ~ 380. It combines the multiplexing advantage of microwave kinetic inductance detectors (MKIDs)7 with planar superconducting filters for dispersing the signal in a single, small superconducting integrated circuit. We demonstrate the two key applications for an instrument of this type: as an efficient redshift machine and as a fast multi-line spectral mapper of extended areas. The line detection sensitivity is in excellent agreement with the instrument design and laboratory performance, reaching the atmospheric foreground photon noise limit on-sky. The design can be scaled to bandwidths in excess of an octave, spectral resolution up to a few thousand and frequencies up to ~1.1 THz. The miniature chip footprint of a few cm2 allows for compact multi-pixel spectral imagers, which would enable spectroscopic direct imaging and large-volume spectroscopic surveys that are several orders of magnitude faster than what is currently possible1–3.By using a superconducting integrated circuit to filter incoming millimetre, submillimetre and far-infrared light from distant galaxies, a prototype spectrometer holds promise for wideband spectrometers that are small, sensitive and scalable to wideband spectroscopic imagers.

We are developing an ultra-wideband spectroscopic instrument, DESHIMA (DEep Spectroscopic HIgh-redshift MApper), based on the technologies of an on-chip filter bank and microwave kinetic inductance detector (MKID) to investigate dusty starburst galaxies in the distant universe at millimeter and submillimeter wavelengths. An on-site experiment of DESHIMA was performed using the ASTE 10-m telescope. We established a responsivity model that converts frequency responses of the MKIDs to line-of-sight brightness temperature. We estimated two parameters of the responsivity model using a set of skydip data taken under various precipitable water vapor (PWV 0.4–3.0 mm) conditions for each MKID. The line-of-sight brightness temperature of sky is estimated using an atmospheric transmission model and the PWVs. As a result, we obtain an average temperature calibration uncertainty of 1 σ = 4 %, which is smaller than other photometric biases. In addition, the average forward efficiency of 0.88 in our responsivity model is consistent with the value expected from the geometrical support structure of the telescope. We also estimate line-of-sight PWVs of each skydip observation using the frequency response of MKIDs and confirm the consistency with PWVs reported by the Atacama Large Millimeter/submillimeter Array.

We are developing an ultra-wideband spectroscopic instrument, DESHIMA (DEep Spectroscopic HIgh-redshift MApper), based on the technologies of an on-chip filter-bank and Microwave Kinetic Inductance Detector (MKID) to investigate dusty star-burst galaxies in the distant universe at millimeter and submillimeter wavelength. An on-site experiment of DESHIMA was performed using the ASTE 10-m telescope. We established a responsivity model that converts frequency responses of the MKIDs to line-of-sight brightness temperature. We estimated two parameters of the responsivity model using a set of skydip data taken under various precipitable water vapor (PWV, 0.4-3.0 mm) conditions for each MKID. The line-of-sight brightness temperature of sky is estimated using an atmospheric transmission model and the PWVs. As a result, we obtain an average temperature calibration uncertainty of \\(1\\sigma=4\\)%, which is smaller than other photometric biases. In addition, the average forward efficiency of 0.88 in our responsivity model is consistent with the value expected from the geometrical support structure of the telescope. We also estimate line-of-sight PWVs of each skydip observation using the frequency response of MKIDs, and confirm the consistency with PWVs reported by the Atacama Large Millimeter/submillimeter Array.

Ultra-wideband 3D imaging spectrometry in the millimeter-submillimeter (mm-submm) band is an essential tool for uncovering the dust-enshrouded portion of the cosmic history of star formation and galaxy evolution. However, it is challenging to scale up conventional coherent heterodyne receivers or free-space diffraction techniques to sufficient bandwidths (\\(\\geq\\)1 octave) and numbers of spatial pixels (>\\(10^2\\)). Here we present the design and first astronomical spectra of an intrinsically scalable, integrated superconducting spectrometer, which covers 332-377 GHz with a spectral resolution of \\(F/\\Delta F \\sim 380\\). It combines the multiplexing advantage of microwave kinetic inductance detectors (MKIDs) with planar superconducting filters for dispersing the signal in a single, small superconducting integrated circuit. We demonstrate the two key applications for an instrument of this type: as an efficient redshift machine, and as a fast multi-line spectral mapper of extended areas. The line detection sensitivity is in excellent agreement with the instrument design and laboratory performance, reaching the atmospheric foreground photon noise limit on sky. The design can be scaled to bandwidths in excess of an octave, spectral resolution up to a few thousand and frequencies up to \\(\\sim\\)1.1 THz. The miniature chip footprint of a few \\(\\mathrm{cm^2}\\) allows for compact multi-pixel spectral imagers, which would enable spectroscopic direct imaging and large volume spectroscopic surveys that are several orders of magnitude faster than what is currently possible.