The Simons Observatory is a ground-based cosmic microwave background survey experiment that consists of three 0.5 m small-aperture telescope (SATs) and one 6 m large-aperture telescope, sited at an elevation of 5200 m in the Atacama Desert in Chile. The SATs will incorporate over 30,000 transition-edge sensor (TES) bolometers in six spectral bands centered between 27 and 280 GHz. The array of SATs are designed specifically to target the primordial B-mode polarization pattern predicted by a class of inflationary cosmological models. The stringent requirements needed to produce this B-mode measurement motivate an innovative instrument design which reduces systematic effects and provides the highest sensitivity possible from the SO observing site. We will present an overview of the design of the SAT and the current status of the instruments as well as results from the first two years of the integration and testing program of the first cryogenic receiver, SAT-MF1.

The TolTEC camera is a next generation three-band imaging polarimeter for the Large Millimeter Telescope. With 7514 lumped element kinetic inductance detectors across three simultaneously observing passbands at 1.1 mm, 1.4 mm, and 2.0 mm, TolTEC has diffraction-limited beams with FWHM of 5, 7, and 11 arcsec, respectively. Herein, we cover a brief overview of the instrument along with the first quantitative measures of TolTEC’s performance at the LMT. We also provide initial reductions of commissioning targets - demonstrating TolTEC's ability to detect both faint and extended structures over a wide dynamic range of flux and angular scales.

The Mexico-UK Submm Camara for Astronomy (MUSCAT) is a 1.1 mm receiver comprising 1458 Horn-Coupled Lumped Element Kinetic Inductance Detectors (LEKIDs) built through a collaborative effort led by Cardiff University in the UK and the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) in Mexico. MUSCAT was successfully installed on the 50 m diameter Large Millimeter Telescope (LMT) Alfonso Serrano, in December 2021 Here we provide an overview of the MUSCAT platform and present on-sky engineering tests results from scientific commissioning data.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

The Simons Observatory (SO) is a ground-based cosmic microwave background (CMB) survey experiment that consists of three 0.5 m small-aperture telescopes (SATs) and one 6 m large-aperture telescope (LAT), sited the Chilean Atacama Desert. The LAT telescope has a 2.4 m diameter cryogenic receiver (LATR) designed to house up to 13 individual optics tubes, where the initial deployment will contain 7 optics tubes with nearly 30,000 transition-edge sensor (TES) bolometers. This telescope will produce arcminute resolution maps over half the microwave sky and measure or constrain numerous cosmological properties. Achieving our scientific goals requires unprecedented sensitivity and control over systematic effects, necessitating an equally unprecedented level of integration and testing for all aspects of the LAT. Here we summarize the design and characterization of the LAT, including the LATR, its optics tubes, and optical characterization of the first Mid-frequency (MF 93/145 GHz) optics tube.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

Microwave absorbers are commonly used as neutral density filters to enable sensitive detectors which saturate with room temperature loads to be characterized in the laboratory setting. We present transmission and reflection measurements of two types of machinable magnetically loaded cured epoxies (Eccosorb MF-112 and MF-114) in millimeter to sub-millimeter wavelengths at room and cryogenic temperatures. These measurements are made using an ultra broadband coherent source (reflection from 30-500 GHz at 300K and transmission from 30-300GHz at 300 and 77K) and a Fourier Transform Spectrometer (70-170 GHz at 4K). We present the dielectric properties of these materials and catalog the differences between presently available machinable samples and commonly cited epoxy-based samples.

The Kinetic Inductance Traveling-Wave Parametric Amplifier (KI-TWPA) has been demonstrating promise as a versatile amplifier that can provide wide instantaneous bandwidth, near quantum limited sensitivity and dynamic range high enough for use in a variety of practical applications including astronomical instruments. Until recently, work on these devices has concentrated on the microwave frequency range below about 10 GHz. Here will discuss a KI-TWPA design based on a microstrip transmission line that is compatible with operation throughout the millimeter-wave band. We present measurements characterizing nonlinearity and loss in the NbTiN microstrip lines used for the new KI-TWPAs as well as results on a waveguide-coupled implementation that shows gain in W-band in good agreement with a model calculation. This model suggests that wideband, quantum limited amplifiers operating up to several hundred GHz should be realizable.

We present recent progress in developing THz QC-VECSELs for use as local oscillators for heterodyne receivers in the 2-5 THz frequency range. The QC-VECSEL is a recently developed external cavity configuration for making THz quantum-cascade lasers (QCLs) with high power, excellent beam quality, and broadband frequency tunability. We discuss electrical frequency tuning characteristics of the QC-VECSEL, sources of noise in the free-running output frequency, and phase-locking to a stable microwave reference (subharmonic diode mixer). We also discuss progress in increasing operating temperature and reducing power consumption of the QC-VECSEL by means of reducing the thickness of the QC-gain material.

DESHIMA 2.0 is an ultra-wideband submillimeter spectrometer based on integrated superconducting microstrip filters and Microwave Kinetic Inductance Detectors (MKIDs). We have successfully demonstrated its ultra-wideband performance in the laboratory. The measured instantaneous frequency coverage with ~300 MKIDs is 225-415 GHz, with a mean filter Q of ~670. The broadband quasi-optical chain of the instrument is characterized by beam patterns across the whole frequency range that are obtained simultaneously by a novel phase-amplitude beam measurement technique. We plan to deploy the instrument on the ASTE telescope for a commissioning and science verification campaign in 2022-2023.

Future cold space borne observatories for the far infrared, such as the Origins Space Telescope, require large arrays of extremely sensitive detector operating in a 1-10 THz band. We present the design, fabrication and characterisation of microwave kinetic inductance detectors (MKIDs) with a high optical coupling efficiency and a noise equivalent power NEP = 4 ⋅ 10^-20 W/√Hz, measured using a thermal calibration source band-pass filtered in a narrow band around 1.55 THz. The devices are antenna-coupled NbTiN-aluminium hybrid MKIDs, optimised for a low NEP, high responsivity and super-THz operation. Key is the use of a very small aluminium volume of ~5 μm3 for radiation absorption, increasing the responsivity by capacitively loading the NbTiN coplanar waveguide section of the resonator and using a thin membrane for the aluminium coplanar waveguide where the THz radiation is absorbed.

Kinetic Inductance Detectors fulfil their great promise of large pixel numbers due to their easiness of multiplexing, as has been witnessed by the astronomic instruments that have become available over the last years. However, the number of available pixels is currently limited by unavoidable scatter in the resonance frequency of individual pixels. We have studied this frequency scatter, and show that it is largely caused by fabrication inhomogeneities, giving rise to variations in critical dimensions on the 10% level. We discuss the intrinsic causes of these inhomogeneities, and possible solutions to avoid them. Moreover, we show that by performing a post-characterisation adaptation step of all individual pixels, we can recover the lost pixels. This result brings 10 kilopixel class KID arrays for mm-wave observation within reach.

The Advanced L-band Phased Array Camera for Astronomy (ALPACA) will be a fully cryogenic phased array feed instrument operating from 1.3-1.7 GHz, providing an unmatched combination of sensitivity, wide bandwidth, and large instantaneous field of view. The instrument was originally targeted for installation at the Arecibo Radio Telescope but the tragic loss of the Gregorian platform in 2020 has led to a proposal to deploy ALPACA at the prime focus of the Green Bank Telescope. Here, we will report on the design and implementation of the antenna array, cryogenic vacuum vessel, signal transport and the digital back end.

Taurus is a mid-latitude super-pressure balloon mission to map the polarization of the cosmic microwave background (CMB) over about 70% of the sky, in four bands from 150 - 350 GHz, and with high fidelity on very large angular scales. The signal on these scales is sensitive to the timing and details of cosmic reionization by the first stars. Knowing the total optical depth of the reionized universe (τ) is also crucial to break degeneracies with other cosmological parameters, most notably the amplitude of scalar fluctuations and the sum of neutrino masses.

TIME, the Tomographic Ionized Carbon Intensity Mapping Experiment, seeks to probe the structure and evolution of the universe by using line intensity mapping to measure carbon monoxide (CO) and ionized carbon ([CII]) with a mm-wavelength grating spectrometer. The measurements of [CII] will probe matter at redshift 5-9 furthering our understanding of reionization and star formation at these early epochs, while the measurements of CO will probe molecular gas from redshift 1-2.  TIME was installed at the Arizona Radio Observatory 12 m telescope in 2019 and returned for further engineering, commissioning, and observing in January 2022. This talk will summarize the technical specifications of the instrument including detector count, spectral coverage and resolution, and will give an update on the current status of the project. We will discuss measurements taken during the 2022 season and discuss the most recent characterization of the transition edge sensors used for TIME.

MUSCAT is a new platform for mm/sub-mm astronomy at the 50m LMT. It is currently configured for 1.1 mm continuum observations with a focal plane consisting of 1458 feedhorn-coupled LEKIDs read out over six frequency division multiplexed RF readout chains with ~250 detectors per readout. We present the performance of the detector readout and tuning system following the initial on-sky commissioning campaign in late 2021. We give details of the readout hardware, the instrument control software, the interfaces between the instrument and telescope control systems, and the automated tuning system for maintaining background-limited performance over the course of an observing night given the varying atmospheric load.

NIST developed MKID arrays based on TiN/Ti multilayers have been successfully deployed, but the 1/f knee of 1 Hz limits their use in some applications. We have created hybrid TiN-Al MKIDs that combine the low TLS noise of the TiN-Si interface with the high sensitivity and 1/f-noise free Al inductors. These hybrid MKIDs have been designed for the photon loadings of the CCAT-prime Project. A sub-array of devices was fabricated, and initial measurements will be shown that indicate that the devices are photon noise limited at the expected loading, with a 1/f knee below 0.1 Hz.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE SPIE Astronomical Telescopes + Instrumentation, 2022.

Digital Frequency-Domain Multiplexing (DfMux) is a transition edge sensor multiplexing technique that has been used in mm-wave receivers with multiplexing factors as high as 68. It is the baseline readout technology for LiteBIRD and a potential upscope option for PICO. Recent efforts have been directed toward simplifying packaging, reducing parasitic impedance, and improving readout noise performance by integrating all cryogenic readout components onto a single cryogenic stage. Here we present recent progress including further improved performance and an increase in the scale of operation. This work marks an important step toward the development of DfMux for space-based mm-wave receivers.

We present recent designs, prototypes, and test results from the ongoing development of SPT-3G+, the fourth-generation receiver of the South Pole Telescope (SPT). SPT-3G+ will utilize single-color, dual-polarization microwave kinetic inductance detectors (MKIDs) to observe the mm/sub-mm sky at 225, 285, and 345 GHz. The SPT-3G+ camera is optimized to measure secondary anisotropies of the cosmic microwave background (CMB) and to study galaxy and cluster formation at high redshift. We review the pixel design and fabrication process and discuss the results of single and multi-pixel characterizations. We then present plans for the full SPT-3G+ MKID arrays and describe design choices made to maximize resonator quality, uniformity, and frequency placement while preserving mapping speed and limiting systematics.

TIM, the Terahertz Intensity Mapper, is a NASA far-infrared balloon mission designed to perform [CII] intensity mapping of the peak of cosmic star formation. To achieve this goal, TIM will fly two grating spectrometers that together cover the 240 to 420 um wavelength range at an R~250. Each spectrometer will require large format arrays (4x~900 detectors) of dual-polarization sensitive detectors, which are photon noise limited at 100 fW of loading. We will present the design of a fully-aluminum lumped-element kinetic-inductance detector (KID) that incorporates a novel “chain-link” absorber design. Operating at 215 mK, we demonstrate that this detector achieves a photon noise limited performance at 80 fW of optical loading with a white noise spectrum down to 1 Hz. Informed by dark measurements, we except these KIDs to achieve a detector limited NEP of 2e-18 W/rt(Hz) at a loading <10 fW. In addition, we shall show our design of a kilopixel array and its initial performance measurements.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

In this poster, we present a new method to measure system temperature Tsys for ALMA submillimeter telescope high frequency observations. Traditional Tsys measurements for ALMA use discrete atmosphere (ATM) calibrations done every few minutes, which usually involves 10 ∼ 20 ATM calibrations at high frequencies. Our new method use water vapor radiometer (WVR) data to track the continuous Tsys. We find a tight linear correlation between Tsys measured using traditional method and Tsys extrapolated based on WVR data with scatter of 0.5% – 3%. We applied the extrapolated semi-continuous Tsys on a few data sets from Band 7 to Band 10 and compare the flux measured using traditional and our new methods. We find the discrete and continuous Tsys methods give us consistent flux measurements with difference up to 5%, while our new method has slightly better flux consistency. This new method can help to save up to 10% of time for ALMA high-frequency observations.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.

This conference presentation was prepared for the Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI conference at SPIE Astronomical Telescopes + Instrumentation, 2022.