Details of the design, fabrication, ground and flight calibration of the High Energy Transmission Grating, HETG, on the Chandra X-ray Observatory are presented after five years of flight experience. Specifics include the theory of phased transmission gratings as applied to the HETG, the Rowland design of the spectrometer, details of the grating fabrication techniques, and the results of ground testing and calibration of the HETG. For nearly six years the HETG has operated essentially as designed, although it has presented some subtle flight calibration effects.

Arrays of discrete, lithographically patterned magnetic elements have been proposed as a new generation of ultrahigh density patterned magnetic storage media. Interferometric lithography has been used to make prototype arrays over large areas with periods of 100–200 nm. Arrays of magnetic pillars, pyramids, and dots have been made by electrodeposition, evaporation and liftoff, and etching processes, and the magnetic properties of the particles and their mutual interactions have been measured.

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Articles you may be interested inOne step electronbeam lithography for multipurpose diffractive optical elements with 200 nm resolution Extendibility of xray lithography to 130 nm ground rules in complex integrated circuit patterns A multilayer inorganic antireflective system for use in 248 nm deep ultraviolet lithography Achromatic interferometric lithography is the preferred approach for producing large-area, spatially coherent 100 nm period gratings and grids. We report on improvements to processes which have enabled exposure areas of Ϸ10 cm 2 . In addition, we report on the fabrication of 100 nm period free-standing gold gratings.

High-resolution spectra of the active binary Capella (G8 III ϩ G1 III) covering the energy range of 0.4-8.0 keV (1.5-30 Å ) show a large number of emission lines, demonstrating the performance of the High-Energy Transmission Grating Spectrometer. A preliminary application of plasma diagnostics provides information on coronal temperatures and densities. Lines arising from different elements in a range of ionization states indicate that Capella has plasma with a broad range of temperatures, from to 7.2, generally consistent with log T p 6.