Filters For Soft X-Ray Solar Telescopes

Spiller, Eberhard; Grebe, K. R.; Golub, L.

doi:10.1117/12.962628

Cited by 7 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Using titanium data from 16 for energies less than 100 eV, and from for greater energies, we see that we can reduce our sensitivity to the 304A line by roughly two orders of magnitude, by either adding or substituting 400A of Ti with the Al filter (figs. [3][4][5]. Ti has L edges at 454 eV and a K edge at 4964.5 eV, but these have little effect on our sensitivity.…”

Section: Expected Off-band Radiationmentioning

confidence: 96%

<title>CUBIC: filters and the space environment</title>

Skinner

Burrows

1993

SPIE Proceedings

View full text Add to dashboard Cite

CUBIC, the Cosmic Unresolved x-ray Background Instrument using CCDs, is instrumented to make non-dispersive spectral observations, with moderate energy resolution over the energy range 200 eV-1O keV1'2. The CUBIC filter set is designed to attenuate optical and UV photons, with special emphasis on blocking geocoronal lines. To still allow useful soft x-ray transmission, a single thin (1200 A) Al/Ti filter has been designed as the Optical/UV blocking filter. Since the detectors are mechanically collimated, the CUBIC filters are susceptible to pin hole punctures from micrometeoroids. We review some of the LDEF micrometeoroid measurements, and find that while there is good probability that micrometeoroids will transit our filter, the holes will be small enough and few enough in number to have no significant impact on our stray light counting rate. Linear Absorption Coefficient DatabaseWe have compiled and combined data from various sources and measurement techniques (optical constants, transmission, etc.) into a data base for Si, Si02, Si3N4, Al, Al2O, Be, Ti. All data have been converted to equivalent a, the linear absorption coefficient, in units of tm1. (Interested parties should contact the authors for details about transferring the data files via FTP.) Knowing the linear absorption coefficient and the thickness of the material, one can compute the transmittance T; the ratio of the incident to absorbed energy, which is related to cx by the relationship T=exp [-cxx], where x is the thickness of the material. Where necessary, the fits to the data were interpolated or extrapolated to cover the energy range 1 eV to 12 keV. Using the database, we can model proposed filters of various materials and thicknesses, including oxide layers, as a function of energy. We used in-house code with specific pixel geometry and gate structure for the CUBIC CCDs to calculate the energy dependent quantum efficiency (QE) and the area•solid angle product (A•)). The expected CUBIC A. , with no blocking filters, is shown below in figures. 1 and 2. Our calculated QE showed good general • agreement with independent optical measurements (400-1000 nm) of a high resistivity CCD (a Lincoln Labs CCID-7)2°O -8194-1255-4/93/$6.OO SPIE Vol. 2006 / 31 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/24/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx o.o. csJ E 11 Expected Off-band RadiationThe CUBIC CCDs have been designed to give optimal soft x-ray response; however, they will be sensitive to out-of-band radiation, chiefly optical. We have employed models of the average night sky brightness, and its energy dependence, to estimate the magnitude of our filtering needs. Previous works8'9 have tabulated the following sources of brightness in the night sky:Zodiacal light 146 S10 (up to 186 in the ecliptic plane) integrated starlight 105 S10 (up to -300 in the galactic plane) airglow 1 S10 (below the atmosphere: 48) galaxies 0.73 S10 + total: 253 5ioThe unit S10 is the average light from ten solar-type stars per squar...

show abstract

Section: Expected Off-band Radiationmentioning

confidence: 96%

<title>CUBIC: filters and the space environment</title>

Skinner

Burrows

1993

SPIE Proceedings

View full text Add to dashboard Cite

show abstract

“…Replacing the transparent Lexan films with red-absorbing phthalocyanine layers allows the use of less carbon for the same light blocking in the visible spectrum [7]. The filters were obtained from Luxel Exposing the flight film to the sun through the telescopes with the filters on the ground for twice the longest exposure time gave no indication of exposure, and we estimate that we had a safety margin against visible light exposure by about a factor 10.…”

Section: Light Blocking Filtermentioning

confidence: 99%

“…The light blocking filter used in the past [7,8] was a carbon-Lexan multilayer structure. Replacing the transparent Lexan films with red-absorbing phthalocyanine layers allows the use of less carbon for the same light blocking in the visible spectrum [7].…”

Section: Light Blocking Filtermentioning

confidence: 99%