10 research outputs found
Wideband 67-116 GHz cryogenic receiver development for ALMA Band 2
The Atacama Large Millimeter/sub-millimeter Array (ALMA) is already
revolutionising our understanding of the Universe. However, ALMA is not yet
equipped with all of its originally planned receiver bands, which will allow it
to observe over the full range of frequencies from 35-950 GHz accessible
through the Earth's atmosphere. In particular Band 2 (67-90 GHz) has not yet
been approved for construction. Recent technological developments in cryogenic
monolithic microwave integrated circuit (MMIC) high electron mobility
transistor (HEMT) amplifier and orthomode transducer (OMT) design provide an
opportunity to extend the originally planned on-sky bandwidth, combining ALMA
Bands 2 and 3 into one receiver cartridge covering 67-116 GHz.
The IF band definition for the ALMA project took place two decades ago, when
8 GHz of on-sky bandwidth per polarisation channel was an ambitious goal. The
new receiver design we present here allows the opportunity to expand ALMA's
wideband capabilities, anticipating future upgrades across the entire
observatory. Expanding ALMA's instantaneous bandwidth is a high priority, and
provides a number of observational advantages, including lower noise in
continuum observations, the ability to probe larger portions of an astronomical
spectrum for, e.g., widely spaced molecular transitions, and the ability to
scan efficiently in frequency space to perform surveys where the redshift or
chemical complexity of the object is not known a priori. Wider IF bandwidth
also reduces uncertainties in calibration and continuum subtraction that might
otherwise compromise science objectives.
Here we provide an overview of the component development and overall design
for this wideband 67-116 GHz cryogenic receiver cartridge, designed to operate
from the Band 2 receiver cartridge slot in the current ALMA front end receiver
cryostat.Comment: 8 pages, proceedings from the 8th ESA Workshop on Millimetre-Wave
Technology and Applications
(https://atpi.eventsair.com/QuickEventWebsitePortal/millimetre-wave/mm-wave
Higher COVID-19 pneumonia risk associated with anti-IFN-α than with anti-IFN-Ï auto-Abs in children
We found that 19 (10.4%) of 183 unvaccinated children hospitalized for COVID-19 pneumonia had autoantibodies (auto-Abs) neutralizing type I IFNs (IFN-alpha 2 in 10 patients: IFN-alpha 2 only in three, IFN-alpha 2 plus IFN-omega in five, and IFN-alpha 2, IFN-omega plus IFN-beta in two; IFN-omega only in nine patients). Seven children (3.8%) had Abs neutralizing at least 10 ng/ml of one IFN, whereas the other 12 (6.6%) had Abs neutralizing only 100 pg/ml. The auto-Abs neutralized both unglycosylated and glycosylated IFNs. We also detected auto-Abs neutralizing 100 pg/ml IFN-alpha 2 in 4 of 2,267 uninfected children (0.2%) and auto-Abs neutralizing IFN-omega in 45 children (2%). The odds ratios (ORs) for life-threatening COVID-19 pneumonia were, therefore, higher for auto-Abs neutralizing IFN-alpha 2 only (OR [95% CI] = 67.6 [5.7-9,196.6]) than for auto-Abs neutralizing IFN-. only (OR [95% CI] = 2.6 [1.2-5.3]). ORs were also higher for auto-Abs neutralizing high concentrations (OR [95% CI] = 12.9 [4.6-35.9]) than for those neutralizing low concentrations (OR [95% CI] = 5.5 [3.1-9.6]) of IFN-omega and/or IFN-alpha 2
Celestial Signals: Are Low-Noise Amplifiers the Future for Millimeter-Wave Radio Astronomy Receivers?
Optimization of spaceflight millimeter-wave impedance matching networks using laser trimming
Wideband 67â116 GHz receiver development for ALMA Band 2
Context. The Atacama Large Millimeter/submillimeter Array (ALMA) has been in operation since 2011, but it has not yet been populated with the full suite of its planned frequency bands. In particular, ALMA Band 2 (67â90 GHz) is the final band in the original ALMA band definition to be approved for production.
Aims. We aim to produce a wideband, tuneable, sideband-separating receiver with 28 GHz of instantaneous bandwidth per polarisation operating in the sky frequency range of 67â116 GHz. Our design anticipates new ALMA requirements following the recommendations of the 2030 ALMA Development Roadmap.
Methods. The cryogenic cartridge is designed to be compatible with the ALMA Band 2 cartridge slot, where the coldest components â the feedhorns, orthomode transducers, and cryogenic low noise amplifiers â operate at a temperature of 15 K. We use multiple simulation methods and tools to optimise our designs for both the passive optics and the active components. The cryogenic cartridge is interfaced with a room-temperature (warm) cartridge hosting the local oscillator and the downconverter module. This warm cartridge is largely based on GaAs semiconductor technology and is optimised to match the cryogenic receiver bandwidth with the required instantaneous local oscillator frequency tuning range.
Results. Our collaboration has resulted in the design, fabrication, and testing of multiple technical solutions for each of the receiver components, producing a state-of-the-art receiver covering the full ALMA Band 2 and 3 atmospheric window. The receiver is suitable for deployment on ALMA in the coming years and it is capable of dual-polarisation, sideband-separating observations in intermediate frequency bands spanning 4â18 GHz for a total of 28 GHz on-sky bandwidth per polarisation channel.
Conclusions. We conclude that the 67â116 GHz wideband implementation for ALMA Band 2 is now feasible and that this receiver provides a compelling instrumental upgrade for ALMA that will enhance observational capabilities and scientific reach
Wideband 67â116 GHz receiver development for ALMA Band 2
Context. The Atacama Large Millimeter/submillimeter Array (ALMA) has been in operation since 2011, but it has not yet been populated with the full suite of its planned frequency bands. In particular, ALMA Band 2 (67â90 GHz) is the final band in the original ALMA band definition to be approved for production.\u3cbr/\u3e\u3cbr/\u3eAims. We aim to produce a wideband, tuneable, sideband-separating receiver with 28 GHz of instantaneous bandwidth per polarisation operating in the sky frequency range of 67â116 GHz. Our design anticipates new ALMA requirements following the recommendations of the 2030 ALMA Development Roadmap.\u3cbr/\u3e\u3cbr/\u3eMethods. The cryogenic cartridge is designed to be compatible with the ALMA Band 2 cartridge slot, where the coldest components â the feedhorns, orthomode transducers, and cryogenic low noise amplifiers â operate at a temperature of 15 K. We use multiple simulation methods and tools to optimise our designs for both the passive optics and the active components. The cryogenic cartridge is interfaced with a room-temperature (warm) cartridge hosting the local oscillator and the downconverter module. This warm cartridge is largely based on GaAs semiconductor technology and is optimised to match the cryogenic receiver bandwidth with the required instantaneous local oscillator frequency tuning range.\u3cbr/\u3e\u3cbr/\u3eResults. Our collaboration has resulted in the design, fabrication, and testing of multiple technical solutions for each of the receiver components, producing a state-of-the-art receiver covering the full ALMA Band 2 and 3 atmospheric window. The receiver is suitable for deployment on ALMA in the coming years and it is capable of dual-polarisation, sideband-separating observations in intermediate frequency bands spanning 4â18 GHz for a total of 28 GHz on-sky bandwidth per polarisation channel.\u3cbr/\u3e\u3cbr/\u3eConclusions. We conclude that the 67â116 GHz wideband implementation for ALMA Band 2 is now feasible and that this receiver provides a compelling instrumental upgrade for ALMA that will enhance observational capabilities and scientific reach.\u3cbr/\u3e\u3cbr/\u3eKey words: instrumentation: interferometer
Wideband 67-116 GHz receiver development for ALMA Band 2
Context. The Atacama Large Millimeter/submillimeter Array (ALMA) has been in operation since 2011, but it has not yet been populated with the full suite of its planned frequency bands. In particular, ALMA Band 2 (67â90 GHz) is the final band in the original ALMA band definition to be approved for production.\u3cbr/\u3e\u3cbr/\u3eAims. We aim to produce a wideband, tuneable, sideband-separating receiver with 28 GHz of instantaneous bandwidth per polarisation operating in the sky frequency range of 67â116 GHz. Our design anticipates new ALMA requirements following the recommendations of the 2030 ALMA Development Roadmap.\u3cbr/\u3e\u3cbr/\u3eMethods. The cryogenic cartridge is designed to be compatible with the ALMA Band 2 cartridge slot, where the coldest components â the feedhorns, orthomode transducers, and cryogenic low noise amplifiers â operate at a temperature of 15 K. We use multiple simulation methods and tools to optimise our designs for both the passive optics and the active components. The cryogenic cartridge is interfaced with a room-temperature (warm) cartridge hosting the local oscillator and the downconverter module. This warm cartridge is largely based on GaAs semiconductor technology and is optimised to match the cryogenic receiver bandwidth with the required instantaneous local oscillator frequency tuning range.\u3cbr/\u3e\u3cbr/\u3eResults. Our collaboration has resulted in the design, fabrication, and testing of multiple technical solutions for each of the receiver components, producing a state-of-the-art receiver covering the full ALMA Band 2 and 3 atmospheric window. The receiver is suitable for deployment on ALMA in the coming years and it is capable of dual-polarisation, sideband-separating observations in intermediate frequency bands spanning 4â18 GHz for a total of 28 GHz on-sky bandwidth per polarisation channel.\u3cbr/\u3e\u3cbr/\u3eConclusions. We conclude that the 67â116 GHz wideband implementation for ALMA Band 2 is now feasible and that this receiver provides a compelling instrumental upgrade for ALMA that will enhance observational capabilities and scientific reach.\u3cbr/\u3e\u3cbr/\u3eKey words: instrumentation: interferometer