New and improved blocking filters (see figure) have been developed for microcalorimeters on several mission payloads, made of high-transmission polyimide support mesh, that can replace the nickel mesh used in previous blocking filter flight designs. To realize the resolution and signal sensitivity of today’s x-ray microcalorimeters, significant improvements in the blocking filter stack are needed.

SUVI (Solar Ultraviolet Imager) Entrance Filter Prototype —150 nm Al on 70 lpi polyimide mesh and an ASTRO-H DMS filter prototype — 80 nm Al on 100 nm polyimide with 70 lpi polyimide mesh.
Using high-transmission polyimide support mesh, it is possible to improve overall throughput on a typical microcalorimeter such as Suzaku’s X-ray Spectrometer by 11%, compared to previous flight designs. Using polyimide to replace standard metal mesh means the mesh will be transparent to energies 3 keV and higher. Incor porating polyimide’s advantageous strength-to-weight ratio, thermal stability, and transmission characteristics permits thinner filter materials, significantly enhancing through put. A prototype contamination blocking filter for ASTRO-H has passed QT-level acoustic testing. Resistive traces can also be incorporated to provide decontamination capability to actively restore filter performance in orbit.

This work was done by David Grove, Jacob Betcher, and Mark Hagen of Luxel Corp. for Goddard Space Flight Center. GSC-16292-1

Topics:
Acoustics Materials Metals Metals Nickel Physical Sciences Powertrains Sun and solar Transmissions
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This article first appeared in the August, 2012 issue of NASA Tech Briefs Magazine (Vol. 36 No. 8).

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