Paul Grimes
A5005403313- Superconducting and THz Device Technology
- Radio Astronomy Observations and Technology
- Microwave Engineering and Waveguides
- Physics of Superconductivity and Magnetism
- Cosmology and Gravitation Theories
- Radio Frequency Integrated Circuit Design
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Superconducting Materials and Applications
- Thermal Radiation and Cooling Technologies
- Advanced Thermodynamic Systems and Engines
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Spacecraft Design and Technology
- Galaxies: Formation, Evolution, Phenomena
- Soil Moisture and Remote Sensing
- Particle accelerators and beam dynamics
- Antenna Design and Optimization
- Photonic and Optical Devices
- Particle Accelerators and Free-Electron Lasers
- Dark Matter and Cosmic Phenomena
- Advanced Semiconductor Detectors and Materials
- Semiconductor Quantum Structures and Devices
- Semiconductor Lasers and Optical Devices
- Particle Detector Development and Performance
Center for Astrophysics Harvard & Smithsonian
2016-2025
Smithsonian Astrophysical Observatory
2012-2024
North Carolina State University
2020-2022
Lawrence Berkeley National Laboratory
2022
Aalto University
2020
The University of Western Australia
2020
UCLA Health
2020
The University of Adelaide
2020
Jet Propulsion Laboratory
2020
Space Information Laboratories (United States)
2020
We present results from an analysis of all data taken by the BICEP2, Keck Array, and BICEP3 CMB polarization experiments up to including 2018 observing season. add additional Array observations at 220 GHz 95 previous 95/150/220 dataset. The Q/U maps now reach depths 2.8, 8.8 μK_{CMB} arcmin 95, 150, GHz, respectively, over effective area ≈600 square degrees ≈400 150 GHz. achieve a signal-to-noise ratio on polarized dust emission exceeding that Planck 353 take auto- cross-spectra between...
We present the Black Hole Explorer (BHEX), a mission that will produce sharpest images in history of astronomy by extending submillimeter Very-Long-Baseline Interferometry (VLBI) to space. BHEX discover and measure bright narrow "photon ring" is predicted exist black holes, produced from light has orbited hole before escaping. This discovery expose universal features hole's spacetime are distinct complex astrophysics emitting plasma, allowing first direct measurements supermassive spin. In...
We report on the design and performance of BICEP3 instrument its first three-year data set collected from 2016 to 2018. is a 52cm aperture, refracting telescope designed observe polarization cosmic microwave background (CMB) degree angular scales at 95GHz. It started science observation South Pole in with 2400 antenna-coupled transition-edge sensor (TES) bolometers. The receiver demonstrated new technologies such as large-diameter alumina optics, Zotefoam infrared filters, flux-activated...
We present estimates of line-of-sight distortion fields derived from the 95 GHz and 150 data taken by BICEP2, BICEP3, Keck Array up to 2018 observing season, leading cosmological constraints a study instrumental astrophysical systematics. Cosmological are three concerning gravitational lensing large-scale structure, polarization rotation magnetic or an axion-like field, screening effect patchy reionization. measure amplitude power spectrum $A_L^{\phi\phi}=0.95 \pm 0.20$. constrain rotation,...
Abstract We characterize Galactic dust filaments by correlating BICEP/Keck and Planck data with polarization templates based on neutral hydrogen (H i ) observations. Dust is important for both our understanding of astrophysical processes in the interstellar medium (ISM) search primordial gravitational waves cosmic microwave background (CMB). In diffuse ISM, H strongly correlated partly organized into that are aligned local magnetic field. analyze deep at 95, 150, 220 GHz, over...
A 12 m diameter radio telescope will be deployed to the Summit Station in Greenland provide direct confirmation of a Super Massive Black Hole (SMBH) by observing its shadow image active galaxy M87. The (Greenland Telescope: GLT) is become one Very Long Baseline Interferometry (VLBI) stations at sub-millimeter (submm) regime, providing longest baseline >9000 km achieve an exceptional angular resolution 20 µas 350 GHz, which enable us resolve size ~40 µas. triangle with baselines formed GLT,...
A detection of curl-type (B-mode) polarization the primary CMB would be direct evidence for inflationary paradigm origin Universe. The Bicep/Keck Array (BK) program targets degree angular scales, where power from primordial B-mode is expected to peak, with ever-increasing sensitivity and has published most stringent constraints on inflation date. Bicep (BA) Stage-3 instrument BK will comprise four Bicep3-class receivers observing at 30/40, 95, 150 220/270 GHz a combined 32,000+ detectors;...
We present an improved search for axionlike polarization oscillations in the cosmic microwave background (CMB) with observations from Keck Array. An all-sky, temporally sinusoidal rotation of CMB polarization, equivalent to a time-variable birefringence, is observable manifestation local axion field and potentially allows polarimeter detect dark matter directly. describe improvements method presented previous work, we demonstrate updated expanded dataset consisting 2012--2015 observing...
The Black Hole Explorer (BHEX) is a space very-long-baseline interferometry (VLBI) mission concept that currently under development. BHEX will study supermassive black holes at unprecedented resolution, isolating the signature of "photon ring" — light has orbited hole before escaping to probe physics edge observable universe. It also measure spins, energy extraction and acceleration mechanisms for jets, characterize mass distribution. achieves high angular resolution by joining with...
We derive an estimator for the lensing potential from galaxy number counts which contains a linear and quadratic term. show that this has much larger signal-to-noise ratio than corresponding intensity mapping. This is due to additional term in count angular power spectrum present already at order. estimate future photometric surveys. Particularly high redshifts, $z\gtrsim 1.5$, signal noise can become of order 30. Therefore, surveys would be excellent means measure tomographic spectra.
The design and test results of a compact C-band orthomode transducer are presented. comprises four rectangular probes orthogonally arranged in circular waveguide, designed to work the WG13 band. Measurements system frequency range 4.64–7.05 GHz agree very well with simulation show cross-polarisation level below −58 dB, return loss about −20 an insertion difference less than 0.18 dB between orthogonal polarisation modes across full waveguide
Future kilopixel-scale heterodyne focal plane arrays based on superconductor-insulator-superconductor (SIS) mixers will require submilliwatt power consumption low-noise amplifiers (LNAs) which are tightly integrated with the mixers. In this paper, an LNA that is optimized for direct connection to a 220-GHz SIS mixer chip and requires less than 100 μW of dc reported. The amplifier design process described, measurement results presented. It shown that, when pumped at local oscillator...
Isolators are important components of low-noise detector and signal processing systems. Conventional wideband edge-mode isolators offer wide bandwidth, but rarely exceeding two octaves. Using modern computer electromagnetic simulation software, one can optimize the isolator circuit expand bandwidth performance. We report on design, fabrication, measurement an operating over a multioctave frequency range, from 4 to 22 GHz at 4-K cryogenic temperature. This has good input output reflection...
Low-power low-noise amplifiers integrated with superconductor-insulator-superconductor (SIS) mixers are required to enable implementation of large-scale focal plane arrays. In this work, a 220-GHz SIS mixer has been high-gain broad-band low-power IF amplifier into compact receiver module. The low noise (LNA) was specifically designed match the output impedance and contributes less than 7 K system temperature over 4-8 GHz frequency range. A 30-45 measured for local oscillator 220 an spanning...
We present a novel machinable 90° waveguide twist design suitable for broadband applications from microwave to terahertz frequency. The achieves compactness and ease of fabrication by utilizing series quarter-wave transformer steps machined in split blocks. Three WR3.4 (220-330 GHz) prototypes with standard UG-387 flanges were fabricated measured. outperform two commercial twists both return loss insertion loss. simulation measurement results show that this performance -25 dB full bandwidth....
Abstract Ground-based observations at terahertz (THz) frequencies are a newly explorable area of astronomy in the coming decades. We discuss science cases for first-generation 10-m class THz telescope, focusing on Greenland Telescope as an example such facility. propose and provide quantitative estimates each case. The largest advantage ground-based telescopes is their higher angular resolution (∼ 4″ dish), compared to space or airborne telescopes. Thus, high-resolution mapping important...
We present the conceptual design of modular detector and readout system for Cosmic Microwave Background – Stage four (CMB-S4) ground-based survey experiment. CMB-S4 will map cosmic microwave background (CMB) millimeter-wave sky to unprecedented sensitivity, using 500,000 superconducting detectors observing from Chile Antarctica over 60% sky. The fundamental building block is a module package operated at 100 mK, which connected amplification chain that carries signals out room temperature. It...
We report the design and successful operation of an superconductor-insulator-superconductor (SIS) mixer operating near superconducting gap niobium. A key feature this is employment a unilateral finline taper to transform waveguide modes microstrip signals. This transition easy since it can be rigorously modeled, also fabricate being single-layer structure. will show that mixers have important advantages at THz frequencies they exhibit wideband both radio frequency (RF) intermediate (IF),...
Since the ALMA North America Prototype Antenna was awarded to Smithsonian Astrophysical Observatory (SAO), SAO and Academia Sinica Institute of Astronomy & Astrophysics (ASIAA) are working jointly relocate antenna Greenland. This paper shows status retrofit work carried out after recommissioning subsequent disassembly at VLA has taken place. The next coming months will see start reassembly Thule Air Base. These activities expected last until fall 2017 when commissioning should take In...
We report the successful operation of a superconductor-insulator-superconductor (SIS) finline mixer operating near superconducting energy gap Nb. The employs new type Pickett-Potter horn-reflector (PPHR) antenna, which exhibits low sidelobes and cross-polarization levels, yet is easy to fabricate. SIS tunnel junction all integrated tuning circuits are fabricated from Nb using planar-circuit technology. an antipodal section, deposited on one side quartz substrate, transforms high impedance...
We present the design and preliminary experimental results of a broadband 650 GHz balanced SIS mixer utilizing two back-to-back unilateral finline tapers. The new employs fully integrated circuit components onto 15 μm silicon-on-insulator (SOI) substrate, hence greatly simplifying block requirements. Independent testing on-chip RF quadrature hybrid DC/IF blocks showed performances consistence with computational predictions. fabricated chip tests have also demonstrated successful operation in...