Optical coating technology for the EUV

Osantowski, John F.; Keski-Kuha, Ritva; Herzig, H.; Toft, Albert R.; Gum, Jeffrey S.; Fleetwood, Charles M.

doi:10.1016/0273-1177(91)90076-v

Cited by 19 publications

(10 citation statements)

References 18 publications

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“…Based on measurements of the individual components and/or replicas of the individual components, the efficiency at 104.8 nm should be the product of the reflectivity of the SiC-coated telescope mirror (46%; Osantowski et al 1991), the grating reflectivity (18%) and the groove efficiency averaged over the '' standard aperture '' of 11 mm (49%) (unpublished measurements in our laboratory), and the quantum efficiency of the KBr-coated XDL detector measured as a component before instrument assembly (18%; Siegmund et al 1994;Kohl et al 1995). The product of these numbers is 0.73%, however, 2.1 times the measured end-to-end value.…”

Section: Radiometric Calibrationmentioning

confidence: 99%

The Helium Focusing Cone of the Local Interstellar Medium Close to the Sun

Michels¹,

Raymond²,

Bertaux³

et al. 2002

ApJ

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The Solar and Heliospheric Observatory (SOHO) Ultraviolet Coronagraph Spectrometer is used to observe the interplanetary He focusing cone within 1 AU. Taken over 2 yr and from differing orbit positions, the series of observations includes measurements of He i 584 Å and Ly intensities. The cone itself is spatially well defined, and the He i intensity within the cone was $45 R in 1996 December, compared with $1 R for lines of sight outward from 1 AU. Between 1996 December and 1998 June, the focusing cone dimmed by a factor of 3.3 as the level of solar activity rose. This is the first time that interstellar helium is observed so near the Sun. Measured intensities are compared to a detailed temperature and density model of interstellar helium in the solar system. The model includes EUV ionization but does not include ionization by electron impact from solar wind electrons. There are several features in the data model comparison that we attribute to the absence of electron impact ionization in the model. The absolute maximum intensity of 45 R first measured in 1996 December calls for an ionization 45% more intense than the EUV photoionization alone as measured by the Solar EUV Monitor/Charge, Element, and Isotope Analysis System (SEM/CELIAS) on SOHO. Important day-to-day variations of the intensity are observed, as well as a general decrease as the solar activity rises (both absolute and divided by a model with a constant ionization). This general decrease is even larger than predicted by a model run with the SEM/CELIAS photoionization rate alone, in spite of a factor of 1.5 increase of this rate from 1996 December to 1998 June. At this time, an additional ionization rate of 0:56 Â 10 À7 s À1 (compared with 1:00 Â 10 À7 s À1 from solar EUV) is required to fit the measured low intensity. We attribute this additional rate to solar wind electron impact ionization of the atoms. This shows that the helium intensity pattern is a very sensitive indicator of the electron density and temperature near the Sun.

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Section: Radiometric Calibrationmentioning

confidence: 99%

The Helium Focusing Cone of the Local Interstellar Medium Close to the Sun

Michels¹,

Raymond²,

Bertaux³

et al. 2002

ApJ

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“…3 Near-normal reflectance of fresh SiC deposited at GOLD. The reflectance of 5 minutes exposed SiC (Larruquert and Keski-Kuha 2000), CVD-SiC (Keski-Kuha et al 1988) and Ir (Osantowski et al 1991) from literature are also displayed for comparison purposes drawback of these coatings is that their reflectance decreases a few percent after exposure to the atmosphere. The reflectance of an unexposed film, that to our knowledge was performed for the first time at GOLD, is shown in Fig.…”

Section: Broad Band Mirrorsmentioning

confidence: 98%

Novel narrow filters for imaging in the 50–150 nm VUV range

Fernández-Perea

Vidal-Dasilva

Larruquert

et al. 2008

Astrophys Space Sci

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GOLD (Grupo de Óptica de Láminas Delgadas) is devoted to the development of novel coatings with challenging performance in the far and the extreme ultraviolet . One of the main goals of this research is to provide the communities of astronomy, solar physics and atmospheric physics with coatings with high reflectance or transmittance at a target wavelength or band, and high rejection of the out-of-band at this complicated spectral range. Above the transparency cutoff of MgF 2 (115 nm), transmittance filters based on Al/MgF 2 multilayers have been developed peaked at wavelengths as short as 124 nm, with a peak transmittance of 27% and a FWHM of 12 nm for a non-aged coating. Below 115 nm, a research on reflectance filters has recently started with very promising results on filters peaked at the 83.4 nm OII spectral line. Fresh filters with 27% peak reflectance at normal incidence and a FWHM of 14 nm have been obtained. Furthermore, the peak reflectance wavelength of these filters can be tuned by rotation. A filter peaked at 83 nm at normal incidence will shift to ∼73 nm at 30 deg from the normal and to ∼58 nm at 45 deg. These novel reflective filters based on Al, Yb and SiO must still demonstrate stability over time.

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“…Photograph of P-ALICE. spectral passband 7 . Additionally, P-ALICE's zero order baffle light trap is treated with a nickel-phosphorus (Ni-P) black coating with very low surface reflectance at EUV/FUV wavelengths 10 .…”

Section: 2mentioning

confidence: 99%

ALICE: The Ultraviolet Imaging Spectrograph Aboard the New Horizons Pluto–Kuiper Belt Mission

et al. 2008

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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 Å spectral passband, a spectral point spread function of 3-6 Å 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.

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Optical coating technology for the EUV

Cited by 19 publications

References 18 publications

The Helium Focusing Cone of the Local Interstellar Medium Close to the Sun

The Helium Focusing Cone of the Local Interstellar Medium Close to the Sun

Novel narrow filters for imaging in the 50–150 nm VUV range

ALICE: The Ultraviolet Imaging Spectrograph Aboard the New Horizons Pluto–Kuiper Belt Mission

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