Receiver Lab Talks: 2024
Questions: Edward Tong
Time: Thursday 12:00 PM EST/EDT
Where: M-340/Zoom
| Date | Speaker | Title | Summary |
|---|---|---|---|
| Oct. 10 | Jacob Kooi JPL |
SOI based 275-373 GHz (ALMA B7) SIS Junction Development for ngEHT | The Microdevices laboratory (MDL) at the Jet Propulsion Laboratory (JPL), with a long history of innovative SIS mixer technology development and fabrication, was contracted in 2021 to deliver quantum limited ALMA band 7 (275 - 373 GHz) SIS mixing devices for the ngEHT. Added goals were device uniformity and high yield for 2SB mixing operation. The intermediate frequency (IF) specification was 16 GHz with a goal of 20 GHz. Further details of the talk is available here. |
| Oct 3 | Edward Tong CfA |
Can an SIS receiver use a comb for its hair? -- a look at RF comb generators | Radio frequency (RF) combs have emerged as a new class of tools for precision phase and group delay calibration in frequency conversion devices and systems. In radio astronomical receivers, RF combs are invaluable for tracking instrumental phase changes, which in turn helps pinpoint atmospheric phase fluctuations. This capability is crucial for implementing the Frequency Phase Transfer technique, aimed at extending the coherent detection time of high-frequency receivers in Very Long Baseline Interferometry (VLBI) observations. In this talk, we will explore various types of RF comb generators that can produce frequency combs in the millimeter wave range. We will also discuss which of these generators is suitable for integration with Superconductor-Insulator-Superconductor (SIS) receivers. |
| Sept 26 | Sara Salem Hesari NRC Herzberg |
Advancements in Single Pixel Radio Receiver Technology at NRC Herzberg | The Radio Instrumentation Team at the National Research Council of Canada's Herzberg Astronomy and Astrophysics Research Centre (HAA) is developing advanced radio systems spanning cm- to sub-mm-wave bands. Their work is centered on technological advancements in receiver systems for current and future radio observatories including ALMA, ngVLA, SKA, Meerkat, CCAT prime and others. This talk will highlight two key R&D projects. Firstly, the development of a dual-linear polarization, single-feed Q-band cryogenic radio astronomy receiver designed for the ngVLA Band 5. Secondly, the design and development of wideband feed and waveguide components that span an octave or more, aimed at broadening the frequency coverage of modern radio receivers. This overview will emphasize the progress and strategic initiatives currently underway at HAA. |
| Sept 19 | Hannah Tomio MIT |
An overview of space-based optical communications, ranging and time transfer |
Optical (or laser) communications offer various advantages over the radio frequency (RF)
communication systems traditionally used for spacecraft. This is particularly true for
small satellites, whose capabilities can be constrained by their limited size, weight,
and power (SWaP). Due to the high directionality of the laser carrier, very high data
rates can be achieved with smaller, lighter, and less power-intensive terminals.
Laser communications also benefit from a less crowded spectrum (in the visible and
near-infrared) with little-to-no regulation; no licensing or frequency allocations are
necessary as with RF systems. The narrow beamwidth of a laser is also more difficult to
intercept, enhancing the security of a laser communications channel as compared to an RF
channel. These advantages have been widely recognized and driven the development of a
variety of laser communication terminals in industry and at research institutes.
This talk will provide an overview of laser communication systems and key technologies, with a particular focus on their relevance for the Black Hole Explorer (BHEX) mission. In addition, we will discuss ongoing developments in leveraging optical communication links for ranging and time-transfer. |
| Sept 12 | Anna Polish CfA/Harvard |
Upgrades to the rotating polarized source for calibrating BICEP3 | The BICEP3 telescope is a 95GHz CMB polarimeter located at the South Pole searching for evidence of inflationary gravitational waves. The polarized CMB signal can also be used to constrain a beyond-the-standard-model parity violation in electromagnetism known as cosmic birefringence. While inflation measurements only require relative calibration of the instrument polarization properties, cosmic birefringence constraints demand absolute polarization angle calibration for each detector. To perform this calibration, we use a rotating, polarized, broadband source whose polarization is carefully referenced to gravity, then observe it in the far field of BICEP3 to transfer the calibration. In this talk I will discuss the challenges involved in building an extremely precise (~0.03deg) absolute polarization calibrator, and improvements we've made for the upcoming Austral summer season. | >
| Sept 5 | John Kovac CfA/Harvard |
Broadband waveguide circular polarizers: revisiting design work from DASI | A novel design for a multi-element broadband waveguide circular polarizer, capable of achieving exceptional circular polarization purity over a 26-36 GHz operating band, was developed for the Degree Angular-Scale Interferometer (DASI) experiment, a LONG time ago when the presenter was a lot younger. DASI was a 13-element compact interferometer which used these polarizers in observations from the South Pole between 2001-2004 to achieve the first detection of polarization of the cosmic microwave background. While the DASI polarizer design (also used by the CBI experiment) employed dielectric elements, scalable all-metal designs were also developed, with claims made that "ultimate polarization precision achievable using this design over a 50% waveguide bandwidth is likely to be limited not by the polarizer, but by limitations of existing broadband OMTs." Possible interest in broadband circular polarizers by the BHEX project motivates quizzing the presenter to see how much of this he can remember. |
| Aug 29 | Stefan Knirck Harvard Physics |
Axion Dark Matter Searches from Radio to Infrared | Axions are excellent candidates for dark matter (DM) and would also explain why the neutron's electric dipole moment is vanishingly small. Under an external magnetic field axions in our own galaxy can convert to photons which can be enhanced in a resonator cavity. We first present our world-leading ADMX (Axion Dark Matter eXperiment) which has excluded QCD axion DM for about an octave in mass range around 4eV (1GHz) and is poised to search up to 16eV (4GHz). Yet, about 6 orders of magnitude of higher masses, up to eV (infrared), remain unprobed. At these masses resonant cavities become infeasible. Hence, we discuss our R&D on novel resonator technology for this range, including MADMAX (Magnetized Disk and Mirror eXperiment) and BREAD (Broadband Experiment for Axion Detection). We highlight our recent, first physics results. I will also discuss the program for my new group at Harvard University, pushing the boundaries of these new technologies into the "THz gap", while leveraging cutting-edge quantum sensing developments and forging international, cross-disciplinary collaborations to achieve a large-scale experimental program for axion discovery. |
| Feb 28 | Keara Carter CfA |
On the Progress of the ngEHT 86/115 GHz Receiver | The unveiling of the first image of a black hole, achieved through the collaborative efforts of the Event Horizon Telescope (EHT) in 2019, is a pivotal moment in astronomy. The next generation Event Horizon Telescope (ngEHT) is now poised to deepen our understanding of black holes through a leap in observational capabilities. The Receiver Lab is headquarters for the development of the 86/115 GHz receiver, designed to leverage the Frequency Phase Transfer Technique (FPT) to further increase the overall sensitivity of the ngEHT. This presentation will outline the receiver subsystem, detail the progress made, and explore the exciting work that lies ahead. |
| Jan 31 | Matt Morgan NRAO |
Integrated Receiver Development | The Integrated Receiver Development program at the NRAO aims to develop compact, mass-producible, and field-replaceable front-end hardware for the next generation of radio telescope facilities. Design principles include early digitaization, as near to the telescope focal plane as possible, and relatively seamless integration of analog, digital and photonic technologies into lightweight, low-overhead, front-end modules. The architecture is optimized to exploit the complementarity of integrated construction techniques and digital signal processing, achieving a level of precision and stability that is unmatched by other radio astronomical receivers. This talk will provide an introduction to the development philosophy, an overview of the team's technical capabilities, and presentation of some of the past, current and ongoing developments, including a suite of warm electronics modules being desinged for the Next Generation Very large Array (ngVLA). |
| Jan 24 | Matthew Petroff CfA |
The Precursor Small Aperture Telescope (PreSAT) CMB Polarimeter | The Precursor Small Aperture Telescope (PreSAT) is envisioned as an early step to the next generation CMB-S4 cosmic microwave background experiment, which will test prototype CMB-S4 components and technologies within an existing BICEP Array receiver, with the aim of enabling full-stack laboratory testing and early risk retirement, along with direct correlation of laboratory component-level performance measurements with deployed system performance. The instrument will utilize new 95/155 GHz dichroic dual-linear-polarization prototype detectors developed for CMB-S4, cooled to 100 mK via a adiabatic demagnetization refrigerator, along with a prototype readout chain and prototype optics manufactured with wide-band anto-reflection coatings. The experience gained by integrating, deploying, and calibrating PreSAT will also help inform planning for CMB-S4 small aperture telescope commissioning, calibration, and operations well in advacne of fabrication of CMB-S4 production hardware. The design and goals of the PreSAT project will be discussed, along with current and near-future laboratory testing plans. |
Previous presentations available here:
CfA managed Google Drive
