4 research outputs found
ALICE: The Ultraviolet Imaging Spectrograph aboard the New Horizons Pluto-Kuiper Belt Mission
The New Horizons ALICE instrument is a lightweight (4.4 kg), low-power (4.4
Watt) imaging spectrograph aboard the New Horizons mission to Pluto/Charon and
the Kuiper Belt. Its primary job is to determine the relative abundances of
various species in Pluto's atmosphere. ALICE will also be used to search for an
atmosphere around Pluto's moon, Charon, as well as the Kuiper Belt Objects
(KBOs) that New Horizons hopes to fly by after Pluto-Charon, and it will make
UV surface reflectivity measurements of all of these bodies as well. The
instrument incorporates an off-axis telescope feeding a Rowland-circle
spectrograph with a 520-1870 angstroms spectral passband, a spectral point
spread function of 3-6 angstroms FWHM, and an instantaneous spatial
field-of-view that is 6 degrees long. Different input apertures that feed the
telescope allow for both airglow and solar occultation observations during the
mission. The focal plane detector is an imaging microchannel plate (MCP) double
delay-line detector with dual solar-blind opaque photocathodes (KBr and CsI)
and a focal surface that matches the instrument's 15-cm diameter
Rowland-circle. In what follows, we describe the instrument in greater detail,
including descriptions of its ground calibration and initial in flight
performance.Comment: 24 pages, 29 figures, 2 tables; To appear in a special volume of
Space Science Reviews on the New Horizons missio
Terahertz-to-infrared converter based on the polyvinylchloride matrix with embedded gold nanoparticles
Abstract
Prospects for the development of devices for visualizing terahertz (THz) radiation sources can be associated with the use of the results of old studies (1965–1978) on the absorption of THz radiation by metal nanoparticles. This “renaissance” demonstrates that metallic nanoparticles can be used as nanotransducers of invisible THz radiation to infrared (IR) radiation detectable by a commercial IR camera. The investigated THz-to-IR converters are matrices that are transparent both in the THz radiation range to be visualized and in the operating range of the IR camera; matrices contain embedded metal nanoparticles. The latter, when irradiated with THz rays, convert the energy of THz photons into heat and become nanosources of IR radiation for the IR camera. In metal nanoparticles, the mechanisms of absorption of THz radiation and its conversion into heat are realized through dissipation of the energy of THz photons due to multiple scattering of electrons, as well as because of excitation of two types of phonons (transverse and longitudinal ones). The conversion of THz energy into the energy of transverse phonons occurs directly, while dissipation and excitation of longitudinal phonons occurs indirectly, through the excitation of Fermi electrons. Polyvinylchloride (PVC) was chosen as the matrix material, and gold nanoparticles were chosen as nanoparticles-fillers
The Ultraviolet Spectrograph on NASA’s Juno Mission
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