Damon Russell

A 6U CubeSat constellation concept for atmospheric temperature and humidity sounding

To accurately predict how the distribution of extreme events may change in the future we need to understand the mechanisms that influence such events in our current climate. This includes understanding how modes of natural climate variability, such as the El Nino Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO) and the Pacific Decadal Oscillation (PDO) impact the weather extremes. Our current observing system is not well-suited for observing extreme events globally due to the sparse sampling and in-homogeneity of ground-based in-situ observations and the infrequent revisit time of satellite observations. Observations of weather extremes, such as extreme precipitation events, temperature extremes, tropical and extra-tropical cyclones among others, with temporal resolution on the order of minutes and spatial resolution on the order of few kms (<;10 kms), are required for improved forecasting of extreme weather events.

Low-Power Very Low-Noise Cryogenic SiGe IF Amplifiers for Terahertz Mixer Receivers

State-of-the-art radio astronomy terahertz receivers utilize clusters of super-conducting mixers with cryogenic IF amplifiers. The critical parameters of the IF amplifiers are noise temperature, bandwidth, power consumption, input return loss, and physical size. This paper presents test data on three approaches to the IF amplifier; two are silicon-germanium (SiGe) monolithic microwave integrated circuit designs and the third is a discrete SiGe transistor miniature module. The amplifiers provide noise temperatures in the range of 5-15 K, from 1 to 6 GHz, at power consumptions as low as 2 mW.

A high-speed cryogenic SiGe channel combiner IC for large photon-starved SNSPD arrays

In this paper, the design and characterization of a cryogenic eight-channel pixel combiner circuit designed to readout superconducting nanowire single photon detectors (SNSPDs) is presented. The circuit is designed to amplify, digitize, edge detect, and combine the output signals of an array of eight SNSPDs. The design has been enabled by the development of novel large-signal cryogenic HBT simulation models. The circuit has been fabricated and measurement results demonstrate excellent agreement with simulation.

Development of the Radiometer Atmospheric CubeSat Experiment payload

The Jet Propulsion Laboratory (JPL) is developing the Radiometer Atmospheric CubeSat Experiment (RACE), which consists of a water vapor radiometer integrated on a 3 U CubeSat platform. RACE will measure 2 channels off the 183 GHz water vapor line, and will be used to validate new low noise amplifier technology and internal calibration methodology. RACE will advance the technology readiness level (TRL) of the 183 GHz receiver subsystem from TRL 4 to TRL 6 and a CubeSat 183 GHz radiometer system from TRL 4 to TRL 7.

The Kilopixel Array Pathfinder Project (KAPPa), a 16 pixel integrated heterodyne focal plane array

KAPPa (the Kilopixel Array Pathfinder Project) is developing key technologies to enable the construction of heterodyne focal plane arrays in the terahertz frequency regime with ~1000 pixels. The leap to ~1000 pixels requires solutions to several key technological problems before the construction of such a focal plane is possible. The KAPPa project will develop a small (16-pixel) 2D integrated heterodyne focal plane array for the 660 GHz atmospheric window as a technological pathfinder towards future kilopixel heterodyne focal plane arrays.

Cryogenic SiGe integrated circuits for superconducting nanowire single photon detector readout

There is a growing interest in developing systems employing large arrays of SNSPDs. To make such instruments practical, it is desirable to perform signal processing before transporting the detector outputs to room temperature. We present a cryogenic eight-channel pixel combiner circuit designed to amplify, digitize, edge detect, and combine the output signals of an array of eight SNSPDs. The circuit has been fabricated and measurement results agree well with expectation. The paper will conclude with a summary of ongoing work and future directions.

Development of an ultra-wide band receiver for the North America array

The North America Array (NAA), also known as the next-generation Very Large Array (ngVLA), is a concept for a radio astronomical interferometric array operating in the frequency range 1.2 GHz to 116 GHz and designed to provide substantial improvements in sensitivity, angular resolution, and frequency coverage while reducing operational costs compared to the current Jansky Very Large Array (JVLA). At JPL, we are designing a single receiver package designed to operate across the 8 to 48 GHz frequency range, in contrast to the current JVLA, which covers this frequency range with five receiver packages. Reducing the number of receiving systems required to cover the full frequency range would reduce operating costs. We are developing a prototype integrated feed-receiver package with a system noise temperature that meets the requirements of the ngVLA/NAA primary science programs, with a design that meets the requirement of low long-term operational costs. The receiver package being developed at JPL consists of a feed horn, low-noise amplifier (LNA), and down-converters to analog intermediate frequencies. We report on the status of this receiver package development.

Results of using permanent magnets to suppress Josephson noise in the KAPPa SIS receiver

We present the results from the magnetic field generation within the Kilopixel Array Pathfinder Project (KAPPa) instrument. The KAPPa instrument is a terahertz heterodyne receiver using a Superconducting-Insulating- Superconducting (SIS) mixers. To improve performance, SIS mixers require a magnetic field to suppress Josephson noise. The KAPPa test receiver can house a tunable electromagnet used to optimize the applied magnetic field. The receiver is also capable of accommodating a permanent magnet that applies a fixed field. Our permanent magnet design uses off-the-shelf neodymium permanent magnets and then reshapes the magnetic field using machined steel concentrators. These concentrators allow the use of an unmachined permanent magnet in the back of the detector block while two small posts provide the required magnetic field across the SIS junction in the detector cavity. The KAPPa test receiver is uniquely suited to compare the permanent magnet and electromagnet receiver performance. The current work includes our design of a ‘U’ shaped permanent magnet, the testing and calibration procedure for the permanent magnet, and the overall results of the performance comparison between the electromagnet and the permanent magnet counterpart.

Large-Area Arrays of WSi Superconducting Nanowire Single Photon Detectors

We report on a 160 μm × 160 μm free-space-coupled array of WSi superconducting nanowire single-photon detectors (SNSPDs) developed for the ground receiver of a deep-space optical communication system.

The kilopixel array pathfinder project (KAPPa), a 16-pixel integrated heterodyne focal plane array: characterization of the single pixel prototype

We report on the laboratory testing of KAPPa, a 16-pixel proof-of-concept array to enable the creation THz imaging spectrometer with -1000 pixels. Creating an array an order of magnitude larger than the existing state of the art of 64 pixels requires a simple and robust design as well as improvements to mixer selection, testing, and assembly. We present the characterization of the single pixel prototype, capable of housing an electromagnet or permanent magnet to suppress Josephson noise. We also present the current 16-pixel array design. This design continually evolves during single pixel testing.