A flexible GPU-accelerated radio-frequency readout for superconducting detectors

We have developed a flexible radio-frequency readout system suitable for a variety of superconducting detectors commonly used in millimeter and submillimeter astrophysics, including kinetic inductance detectors (KIDs), Thermal KID bolometers, and quantum capacitance detectors. Our system avoids custom FPGA-based readouts and instead uses commercially available software radio hardware for analog to digital converter chip/digital to analog converter chip and a GPU to handle real-time signal processing. Because this system is written in common C++/CUDA, the range of different algorithms that can be quickly implemented make it suitable for the readout of many others cryogenic detectors and for the testing of different and possibly more effective data acquisition schemes

A flexible GPU-accelerated radio-frequency readout for superconducting detectors

We have developed a flexible radio-frequency readout system suitable for a variety of superconducting detectors commonly used in millimeter and submillimeter astrophysics, including kinetic inductance detectors (KIDs), Thermal KID bolometers, and quantum capacitance detectors. Our system avoids custom FPGA-based readouts and instead uses commercially available software radio hardware for analog to digital converter chip/digital to analog converter chip and a GPU to handle real-time signal processing. Because this system is written in common C++/CUDA, the range of different algorithms that can be quickly implemented make it suitable for the readout of many others cryogenic detectors and for the testing of different and possibly more effective data acquisition schemes

Thermal kinetic inductance detectors for ground-based millimeter-wave cosmology

We show measurements of thermal kinetic inductance detectors (TKID) intended for millimeter wave cosmology in the 200-300 GHz atmospheric window. The TKID is a type of bolometer which uses the kinetic inductance of a superconducting resonator to measure the temperature of the thermally isolated bolometer island. We measure bolometer thermal conductance, time constant and noise equivalent power. We also measure the quality factor of our resonators as the bath temperature varies to show they are limited by effects consistent with coupling to two level systems.Comment: 8 pages, 4 figures. Submitted to Journal of Low Temperature Physic

Thermal Kinetic Inductance Detectors for millimeter-wave detection

Thermal Kinetic Inductance Detectors (TKIDs) combine the excellent noise performance of traditional bolometers with a radio frequency multiplexing architecture that enables the large detector counts needed for the next generation of millimeter-wave instruments. In this paper, we first discuss the expected noise sources in TKIDs and derive the limits where the phonon noise contribution dominates over the other detector noise terms: generation-recombination, amplifier, and two-level system (TLS) noise. Second, we characterize aluminum TKIDs in a dark environment. We present measurements of TKID resonators with quality factors of about $10^5$ at 80 mK. We also discuss the bolometer thermal conductance, heat capacity, and time constants. These were measured by the use of a resistor on the thermal island to excite the bolometers. These dark aluminum TKIDs demonstrate a noise equivalent power NEP = $2 \times 10^{-17} \mathrm{W}/\mathrm{\sqrt{Hz}}$, with a $1/f$ knee at 0.1 Hz, which provides background noise limited performance for ground-based telescopes observing at 150 GHz.Comment: 15 pages, 12 figure

A millimeter-wave kinetic inductance detector camera for long-range imaging through optical obscurants

Millimeter-wave imaging provides a promising option for long-range target detection through optical obscurants such as fog, which often occur in marine environments. Given this motivation, we are currently developing a 150 GHz polarization-sensitive imager using a relatively new type of superconducting pair-breaking detector, the kinetic inductance detector (KID). This imager will be paired with a 1.5 m telescope to obtain an angular resolution of 0.09° over a 3.5° field of view using 3,840 KIDs. We have fully characterized a prototype KID array, which shows excellent performance with noise strongly limited by the irreducible fluctuations from the ambient temperature background. Full-scale KID arrays are now being fabricated and characterized for a planned demonstration in a maritime environment later this year

Antenna-coupled thermal kinetic inductance detectors for ground-based millimeter-wave cosmology

We present our design for antenna-coupled thermal kinetic inductance detectors (TKIDs) designed for Cosmic Microwave Background (CMB) observations in the 150 GHz band. The next generation of telescopes studying the CMB will require large arrays of detectors on cryogenic focal planes to achieve high sensitivity at the cost of increased integration and readout complexity. TKIDs have demonstrated photon-limited noise performance comparable to traditional bolometers with a radiofrequency (RF) multiplexing architecture that enables the large detector counts needed. We characterize TKIDs fabricated for observing the CMB in a frequency band centered at 150 GHz and discuss the optical performance. These devices are a critical step towards fielding a Keck Array camera with 512 devices on the focal plane at the South Pole

MKID development for SuperSpec: an on-chip, mm-wave, filter-bank spectrometer

SuperSpec is an ultra-compact spectrometer-on-a-chip for millimeter and submillimeter wavelength astronomy. Its very small size, wide spectral bandwidth, and highly multiplexed readout will enable construction of powerful multibeam spectrometers for high-redshift observations. The spectrometer consists of a horn-coupled microstrip feedline, a bank of narrow-band superconducting resonator filters that provide spectral selectivity, and Kinetic Inductance Detectors (KIDs) that detect the power admitted by each filter resonator. The design is realized using thin-film lithographic structures on a silicon wafer. The mm-wave microstrip feedline and spectral filters of the first prototype are designed to operate in the band from 195-310 GHz and are fabricated from niobium with at Tc of 9.2K. The KIDs are designed to operate at hundreds of MHz and are fabricated from titanium nitride with a Tc of 2K. Radiation incident on the horn travels along the mm-wave microstrip, passes through the frequency-selective filter, and is finally absorbed by the corresponding KID where it causes a measurable shift in the resonant frequency. In this proceedings, we present the design of the KIDs employed in SuperSpec and the results of initial laboratory testing of a prototype device. We will also briefly describe the ongoing development of a demonstration instrument that will consist of two 500-channel, R=700 spectrometers, one operating in the 1-mm atmospheric window and the other covering the 650 and 850 micron bands.Comment: As submitted, except that "in prep" references have been update