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"Raffanti, Rick"
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The Ultraviolet Spectrograph on NASA’s Juno Mission
by
Rhoad, Cherie L.
,
Davis, Michael W.
,
Bonfond, Bertrand
in
Aerospace Technology and Astronautics
,
Astrophysics and Astroparticles
,
Auroral emissions
2017
The ultraviolet spectrograph instrument on the Juno mission (Juno-UVS) is a long-slit imaging spectrograph designed to observe and characterize Jupiter’s far-ultraviolet (FUV) auroral emissions. These observations will be coordinated and correlated with those from Juno’s other remote sensing instruments and used to place in situ measurements made by Juno’s particles and fields instruments into a global context, relating the local data with events occurring in more distant regions of Jupiter’s magnetosphere. Juno-UVS is based on a series of imaging FUV spectrographs currently in flight—the two Alice instruments on the Rosetta and New Horizons missions, and the Lyman Alpha Mapping Project on the Lunar Reconnaissance Orbiter mission. However, Juno-UVS has several important modifications, including (1) a scan mirror (for targeting specific auroral features), (2) extensive shielding (for mitigation of electronics and data quality degradation by energetic particles), and (3) a cross delay line microchannel plate detector (for both faster photon counting and improved spatial resolution). This paper describes the science objectives, design, and initial performance of the Juno-UVS.
Journal Article
GRAPH -- An readout ASIC for large MCP based detectors
by
Liu, Gang
,
Seljak, Andrej
,
Vallerga, John
in
Application specific integrated circuits
,
Low noise
,
Noise sensitivity
2024
We present a programmable 16 channel, mixed signal, low power readout ASIC, having the project historically named Gigasample Recorder of Analog waveforms from a PHotodetector (GRAPH). It is designed to read large aperture single photon imaging detectors using micro channel plates for charge multiplication, and measuring the detector's response on crossed strips anodes to extrapolate the incoming photon position. Each channel consists of a fast, low power and low noise charge sensitive amplifier, which provides a myriad of coarse and fine programmable options for gain and shaping settings. Further, the amplified signal is recorded using, to our knowledge novel, the Hybrid Universal sampLing Architecture (HULA), a mixed signal double buffer memory, that enables concurrent waveform recording, and selected event digitized data extraction. The sampling frequency is freely adjustable between few~kHz up to 125~MHz, while the chip's internal digital memory holds a history 2048 samples for each channel, with a digital headroom of 12 bits. An optimized region of interest sample-read algorithm allows to extract the information just around the event pulse peak, while selecting the next event, thus substantially reducing the operational dead time. The chip is designed in 130~\\(n\\)m TSMC CMOS technology, and its power consumption is around 47~\\(m\\)W per channel.
GRAPH -- An readout ASIC for large MCP based detectors
by
Liu, Gang
,
Seljak, Andrej
,
Varner, Gary S
in
Algorithms
,
Application specific integrated circuits
,
Low noise
2024
We present a programmable 16 channel, mixed signal, low power readout ASIC, having the project historically named Gigasample Recorder of Analog waveforms from a PHotodetector (GRAPH). It is designed to read large aperture single photon imaging detectors using micro channel plates for charge multiplication, and measuring the detector's response on crossed strips anodes to extrapolate the incoming photon position. Each channel consists of a fast, low power and low noise charge sensitive amplifier, which provides a myriad of coarse and fine programmable options for gain and shaping settings. Further, the amplified signal is recorded using, to our knowledge novel, the Hybrid Universal sampLing Architecture (HULA), a mixed signal double buffer memory, that enables concurrent waveform recording, and selected event digitized data extraction. The sampling frequency is freely adjustable between few~kHz up to 125~MHz, while the chip's internal digital memory holds a history 2048 samples for each channel, with a digital headroom of 12 bits. An optimized region of interest sample-read algorithm allows to extract the information just around the event pulse peak, while selecting the next event, thus substantially reducing the operational dead time. The chip is designed in 130~\\(n\\)m TSMC CMOS technology, and its power consumption is around 47~\\(m\\)W per channel.
Panoramic SETI: Overall focal plane electronics and timing and network protocols
2021
The PANOSETI experiment is an all-sky, all-the-time visible search for nanosecond to millisecond time-scale transients. The experiment will deploy observatory domes at several sites, each dome containing ~45 telescopes and covering ~4,440 square degrees. Here we describe the focal-plane electronics for the visible wavelength telescopes, each of which contains a Mother Board and four Quadrant Boards. On each quadrant board, 256 silicon photomultiplier (SiPM) photon detectors are arranged to measure pulse heights to search for nanosecond time-scale pulses. To simultaneously examine pulse widths over a large range of time scales (nanoseconds to milliseconds), the instrument implements both a Continuous Imaging Mode (CI-Mode) and a Pulse Height Mode (PH-Mode). Precise timing is implemented in the gateware with the White Rabbit protocol.
Panoramic SETI: Program Update and High-Energy Astrophysics Applications
2022
Optical SETI (Search for Extraterrestrial Intelligence) instruments that can explore the very fast time domain, especially with large sky coverage, offer an opportunity for new discoveries that can complement multimessenger and time domain astrophysics. The Panoramic SETI experiment (PANOSETI) aims to observe optical transients with nanosecond to second duration over a wide field-of-view (\\(\\thicksim\\)2,500 sq.deg.) by using two assemblies of tens of telescopes to reject spurious signals by coincidence detection. Three PANOSETI telescopes, connected to a White Rabbit timing network used to synchronize clocks at the nanosecond level, have been deployed at Lick Observatory on two sites separated by a distance of 677 meters to distinguish nearby light sources (such as Cherenkov light from particle showers in the Earth's atmosphere) from astrophysical sources at large distances. In parallel to this deployment, we present results obtained during four nights of simultaneous observations with the four 12-meter VERITAS gamma-ray telescopes and two PANOSETI telescopes at the Fred Lawrence Whipple Observatory. We report PANOSETI's first detection of astrophysical gamma rays, comprising three events with energies in the range between \\(\\thicksim\\)15 TeV and \\(\\thicksim\\)50 TeV. These were emitted by the Crab Nebula, and identified as gamma rays using joint VERITAS observations.
The Black Hole Explorer: Back End Electronics
by
Haworth, Kari
,
Cheimets, Peter
,
Marrone, Daniel
in
Analog to digital converters
,
Bandwidths
,
Data transmission
2024
This paper describes specification and early design of back end signal processing subsystems for the Black Hole Explorer (BHEX) Very Long Baseline Interferometry (VLBI) space telescope. The \"back end\" consists of two subsystems. First, the block downconverter (BDC) is a heterodyne system that performs a frequency translation of the analog signal from IF to baseband and amplifies and filters it for digitization. Second, the digital back end (DBE) samples the analog signal with an analog-to-digital converters (ADC) and digitally processes the data stream formatting them to the VLBI \"VDIF\" standard and converting to Ethernet packets for 100 gigabit-per-second (Gb/s) Ethernet transport to the optical downlink system. Both the BDC and the DBE for BHEX support eight channels of 4.096 GHz bandwidth each, for a total processed bandwidth of 32.768 GHz. The BHEX back end benefits from mature terrestrial back end heritage, described in some detail. The BHEX back end itself is in the early stages of design, with requirements, interface specifications, and component trade studies well advanced. The aim is to build a prototype using terrestrial grade parts which are available in functionally identical space grade equivalents, and to use this prototype to advance the back end Technology Readiness Level (TRL) preparing for a Small Explorer (SMEX) proposal in 2025.
Panoramic SETI: overall mechanical system design
by
Wright, Shelley A
,
Wiley, James H
,
Horowitz, Paul
in
Extraterrestrial intelligence
,
Extraterrestrial life
,
Field of view
2021
PANOSETI (Pulsed All-Sky Near-infrared Optical Search for Extra Terrestrial Intelligence) is a dedicated SETI (Search for Extraterrestrial Intelligence) observatory that is being designed to observe 4,441 sq. deg. to search for nano- to milli-second transient events. The experiment will have a dual observatory system that has a total of 90 identical optical 0.48 m telescopes that each have a 99 square degree field of view. The two observatory sites will be separated by 1 km distance to help eliminate false positives and register a definitive signal. We discuss the overall mechanical design of the telescope modules which includes a Fresnel lens housing, a shutter, three baffles, an 32x32 array of Hamamatsu Multi-Photon Pixel Counting (MPPC) detectors that reside on a linear stage for focusing. Each telescope module will be housed in a triangle of a 3rd tessellation frequency geodesic dome that has the ability to have directional adjustment to correct for manufacturing tolerances and astrometric alignment to the second observatory site. Each observatory will have an enclosure to protect the experiment, and an observatory room for operations and electronics. We will review the overall design of the geodesic domes and mechanical telescope attachments, as well as the overall cabling and observatory infrastructure layout.
Panoramic optical and near-infrared SETI instrument: optical and structural design concepts
by
Wright, Shelley A
,
Howard, Andrew W
,
Chaim-Weismann, Samuel A
in
Apertures
,
Domes
,
Energy transfer
2018
We propose a novel instrument design to greatly expand the current optical and near-infrared SETI search parameter space by monitoring the entire observable sky during all observable time. This instrument is aimed to search for technosignatures by means of detecting nano- to micro-second light pulses that could have been emitted, for instance, for the purpose of interstellar communications or energy transfer. We present an instrument conceptual design based upon an assembly of 198 refracting 0.5-m telescopes tessellating two geodesic domes. This design produces a regular layout of hexagonal collecting apertures that optimizes the instrument footprint, aperture diameter, instrument sensitivity and total field-of-view coverage. We also present the optical performance of some Fresnel lenses envisaged to develop a dedicated panoramic SETI (PANOSETI) observatory that will dramatically increase sky-area searched (pi steradians per dome), wavelength range covered, number of stellar systems observed, interstellar space examined and duration of time monitored with respect to previous optical and near-infrared technosignature finders.
Panoramic optical and near-infrared SETI instrument: overall specifications and science program
by
Wright, Shelley A
,
Howard, Andrew W
,
Chaim-Weismann, Sam
in
Dwell time
,
Extraterrestrial intelligence
,
Extraterrestrial life
2018
We present overall specifications and science goals for a new optical and near-infrared (350 - 1650 nm) instrument designed to greatly enlarge the current Search for Extraterrestrial Intelligence (SETI) phase space. The Pulsed All-sky Near-infrared Optical SETI (PANOSETI) observatory will be a dedicated SETI facility that aims to increase sky area searched, wavelengths covered, number of stellar systems observed, and duration of time monitored. This observatory will offer an \"all-observable-sky\" optical and wide-field near-infrared pulsed technosignature and astrophysical transient search that is capable of surveying the entire northern hemisphere. The final implemented experiment will search for transient pulsed signals occurring between nanosecond to second time scales. The optical component will cover a solid angle 2.5 million times larger than current SETI targeted searches, while also increasing dwell time per source by a factor of 10,000. The PANOSETI instrument will be the first near-infrared wide-field SETI program ever conducted. The rapid technological advance of fast-response optical and near-infrared detector arrays (i.e., Multi-Pixel Photon Counting; MPPC) make this program now feasible. The PANOSETI instrument design uses innovative domes that house 100 Fresnel lenses, which will search concurrently over 8,000 square degrees for transient signals (see Maire et al. and Cosens et al., this conference). In this paper, we describe the overall instrumental specifications and science objectives for PANOSETI.
Panoramic optical and near-infrared SETI instrument: prototype design and testing
by
Wright, Shelley A
,
Howard, Andrew W
,
Chaim-Weismann, Samuel A
in
Angular resolution
,
Extraterrestrial intelligence
,
Extraterrestrial life
2018
The Pulsed All-sky Near-infrared Optical Search for ExtraTerrestrial Intelligence (PANOSETI) is an instrument program that aims to search for fast transient signals (nano-second to seconds) of artificial or astrophysical origin. The PANOSETI instrument objective is to sample the entire observable sky during all observable time at optical and near-infrared wavelengths over 300 - 1650 nm\\(^1\\). The PANOSETI instrument is designed with a number of modular telescope units using Fresnel lenses (\\(\\sim\\)0.5m) arranged on two geodesic domes in order to maximize sky coverage\\(^2\\). We present the prototype design and tests of these modular Fresnel telescope units. This consists of the design of mechanical components such as the lens mounting and module frame. One of the most important goals of the modules is to maintain the characteristics of the Fresnel lens under a variety of operating conditions. We discuss how we account for a range of operating temperatures, humidity, and module orientations in our design in order to minimize undesirable changes to our focal length or angular resolution.