Mr. John M. D'Ewart Profile

John M. D'Ewart

at SLAC National Accelerator Lab

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Author

Publications (4)

Proceedings Article | 31 August 2022 Presentation + Paper

Advanced RFSoC readout for space-based superconducting sensor arrays

Shawn Henderson, Zeeshan Ahmed, John D'Ewart, Josef Frisch, Ryan Herbst, Chao Liu, Lili Ma, Larry Ruckman, Daniel Van Winkle, Cyndia Yu

Proceedings Volume 12190, 121900N (2022) https://doi.org/10.1117/12.2630412

KEYWORDS: Sensors, Space operations, Superconductors, Digital signal processing, Prototyping, Signal processing, X-ray astronomy, Power supplies

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Low-energy threshold, high-resolution superconducting detector arrays with 103–105 pixels are increasingly necessary in ground- and space-based telescopes across the electromagnetic spectrum including mm-wave, far-infrared (Far-IR), near-infrared, X-ray, and gamma rays. Reading out such large numbers of sensors poses significant technical challenges, but recent cryogenic readout technology developments are enabling the simultaneous read out of significantly more channels with minimal performance impact. An especially promising set of cold readout technologies couple cryogenic sensors to superconducting resonators. These technologies rely on high-frequency RF electronics to interrogate and demodulate the sensors’ signals using digitally generated tones. Recently released Radio Frequency Systems-on-Chip (RFSoC) devices from Xilinx combine a FPGA with high-speed ADCs and DACs onto a single chip. These systems provide significant advantages for these applications, including lower cost, reduced size and weight, lower power consumption, and improved RF performance. While an RFSoC-based warm readout system would be attractive for a broad range of spacecraft applications, Xilinx has not announced plans for a space qualified version of its RFSoC devices and insufficient data is publicly available to evaluate the feasibility of using RFSoC devices in space. To evaluate the suitability of RFSoC devices for spacecraft applications, we have designed and built custom boards using all space-qualified components except for the RFSoC. In this contribution we present the design of our custom RFSoC board, measurements of critical aspects of board performance which relate to operation in the harsh space environment, and measurements of integrated RF performance targeting the readout of large superconducting sensor arrays and space-based radio spectrometry. In addition to a wide range of spacecraft applications including communications and radar, our RFSoC platform is a potentially critically enabling technology for missions prioritized by the recent 2020 Decadal Survey on Astronomy and Astrophysics including flagship Far-IR and X-ray missions, as well as Far-IR, X-ray, and Cosmic Microwave Background (CMB) probes.

Proceedings Article | 31 August 2022 Poster + Paper

A simulation suite for readout with SMuRF tone-tracking electronics

Cyndia Yu, Zeeshan Ahmed, J. D'Ewart, Josef Frisch, Shawn Henderson, Maximiliano Silva-Feaver

Proceedings Volume 12190, 121900V (2022) https://doi.org/10.1117/12.2629718

KEYWORDS: Resonators, Signal detection, Sensors, Modulation, Calibration, Electronics, Error analysis, Detection and tracking algorithms, Demodulation, Digital signal processing

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Proceedings Article | 18 July 2018 Paper

Highly-multiplexed microwave SQUID readout using the SLAC Microresonator Radio Frequency (SMuRF) electronics for future CMB and sub-millimeter surveys

Shawn Henderson, Zeeshan Ahmed, Jason Austermann, Daniel Becker, Douglas Bennett, David Brown, Saptarshi Chaudhuri, Hsiao-Mei Sherry Cho, John D'Ewart, Bradley Dober, Shannon Duff, John Dusatko, Sofia Fatigoni, Josef Frisch, Jonathon Gard, Mark Halpern, Gene Hilton, Johannes Hubmayr, Kent Irwin, Ethan Karpel, Sarah Kernasovskiy, Stephen Kuenstner, Chao-Lin Kuo, Dale Li, John A. Mates, Carl Reintsema, Stephen Smith, Joel Ullom, Leila Vale, Daniel Van Winkle, Michael Vissers, Cyndia Yu

Proceedings Volume 10708, 1070819 (2018) https://doi.org/10.1117/12.2314435

KEYWORDS: Resonators, Multiplexers, Microwave radiation, Cryogenics, Multiplexing, Electronics, Sensors, Field programmable gate arrays, Amplifiers

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The next generation of cryogenic CMB and submillimeter cameras under development require densely instrumented sensor arrays to meet their science goals. The readout of large numbers (~10,000-100,000 per camera) of sub-Kelvin sensors, for instance as proposed for the CMB-S4 experiment, will require substantial improvements in cold and warm readout techniques. To reduce the readout cost per sensor and integration complexity, efforts are presently focused on achieving higher multiplexing density while maintaining readout noise subdominant to intrinsic detector noise and presenting manageable thermal loads. Highly-multiplexed cold readout technologies in active development include Microwave Kinetic Inductance Sensors (MKIDs) and microwave rf-SQUIDs. Both exploit the high quality factors of superconducting microwave resonators to densely channelize sub-Kelvin sensors into the bandwidth of a microwave transmission line. In the case of microwave SQUID multiplexing, arrays of transition-edge sensors (TES) are multiplexed by coupling each TES to its own superconducting microwave resonator through an rf-SQUID. We present advancements in the development of a new warm readout system for microwave SQUID multiplexing, the SLAC Superconducting Microresonator RF electronics, or SMuRF, by adapting SLAC National Accelerator Laboratory's Advanced Telecommunications Computing Architecture (ATCA) FPGA Common Platform. SMuRF aims to read out 4000 microwave SQUID channels between 4 and 8 GHz per RF line. Each compact SMuRF system is built onto a single ATCA carrier blade. Daughter boards on the blade implement RF frequency-division multiplexing using FPGAs, fast DACs and ADCs, and an analog up- and down-conversion chain. The system reads out changes in flux in each resonator-coupled rf-SQUID by monitoring the change in the transmitted amplitude and frequency of RF tones produced at each resonator's fundamental frequency. The SMuRF system is unique in its ability to track each tone, minimizing the total RF power required to readout each resonator, thereby significantly reducing the linearity requirements on the cold and warm readout. Here, we present measurements of the readout noise and linearity of the first full SMuRF system, including a demonstration of closed-loop tone tracking on a 528 channel cryogenic microwave SQUID multiplexer. SMuRF is being explored as a potential readout solution for a number of future CMB projects including Simons Observatory, BICEP Array, CCAT-prime, Ali-CPT, and CMB-S4. In addition, parallel development of the platform is underway to adapt SMuRF to read out both MKID and fast X-ray TES calorimeter arrays.

Proceedings Article | 10 July 2018 Presentation

Readout demonstration of 512 TES bolometers using a single microwave SQUID multiplexer (Conference Presentation)

Bradley Dober, Zeeshan Ahmed, Jason Austermann, Daniel Becker, Douglas Bennett, David Brown, Saptarshi Chaudhuri, Hsiao-Mei Sherry Cho, John D'Ewart, Shannon Duff, John Dusatko, Sofia Fatigoni, Josef Frisch, Johnathon Gard, Mark Halpern, Shawn Henderson, Gene Hilton, Johannes Hubmayr, Kent Irwin, Ethan Karpel, Sarah Kernasovskiy, John A. Mates, Carl Reintsema, Michael Vissers, Leila Vale, Joel Ullom, Stephen Kuenstner, Chao-Lin Kuo, Dale Li, Stephen Smith, Daniel Van Winkle, Betty Young, Cyndia Yu

Proceedings Volume 10708, 1070818 (2018) https://doi.org/10.1117/12.2314231

KEYWORDS: Multiplexers, Microwave radiation, Bolometers, Sensors, Resonators, Multiplexing, Receivers, Modulation, Cameras, Observatories

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To enable the next-generation of bolometric cameras, we are developing the microwave SQUID multiplexer (μMUX). Upcoming receivers such as Simons Observatory, CCAT-prime, BICEP array, Ali-CPT, and CMB-S4 plan to instrument focal planes with 50,000-500,000 sensors. Sensor count is achieved by tiling many 150 mm-diameter densely packed detector arrays into these focal planes. The fabrication and quality of large-format bolometer arrays has been demonstrated and is now mature. In contrast, the readout technology required for next-generation receivers needs development. The sensitivity, low cross-talk, high multiplexing density, and small component size make the μMUX well-suited for this goal. In this approach, the TES signal modulates the inductance of an rf-SQUID that loads a high-Q microwave resonator. The coupled signal therefore modulates the microwave resonance frequency, which may be read out using homodyne techniques. By coupling each resonator to the same microwave feedline, many detectors can be read out on a single coaxial cable pair. The multiplexing density is in practice limited by signal bandwidth, allowable cross-talk, and the digitization bandwidth of room-temperature readout electronics. We present the design and performance of a scalable 64-channel multiplexer chip optimized for bolometric applications. We utilize a new quarter wave resonator design that increases the physical linear density by a factor of two, therefore achieving a smaller footprint for simplified detector packaging. Measurements of this design show 100 kHz resonator bandwidth, uniform 1.8 MHz frequency spacing, and an input referred current noise of 35 pA/√Hz that is well below the level of an optimized, background-limited TES bolometer. Using 8 daisy-chained and frequency scaled chips, we create a 512-channel multiplexer and use it to readout a 512 TES-bolometer array. We present the results of this large-scale μMUX demonstration including system yield, signal cross-talk, and an analysis of noise in various TES bias configurations. The result demonstrates the multiplexing density required to read out 2,000 sensors between 4-8 GHz.

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