Advances in reflection grating technology for Constellation-X

Ralf K. Heilmann, Mireille Akilian, Chih Hao Chang, Carl G. Chen, Craig R. Forest, Chulmin Joo, Paul T. Konkola, Juan C. Montoya, Yanxia Sun, Jenny You, Mark L. Schattenburg

Research output: Contribution to journalConference articlepeer-review


The Reflection Grating Spectrometer (RGS) on Constellation-X will require thousands of large gratings with very exacting tolerances. Two types of grating geometries have been proposed. In-plane gratings have low ruling densities (∼ 500 l/mm) and very tight flatness and assembly tolerances. Off-plane gratings require much higher ruling densities (∼ 5000 l/mm), but have somewhat relaxed flatness and assembly tolerances and offer the potential of higher resolution and efficiency. The trade-offs between these designs are complex and are currently being studied. To help address critical issues of manufacturability we are developing a number of novel technologies for shaping, assembling, and patterning large-area reflection gratings that are amenable to low-cost manufacturing. In particular, we report results of improved methods for patterning the sawtooth grating lines that are required for efficient blazing, including the use of anisotropic etching of specially-cut silicon wafers to pattern atomically smooth grating facets. We also report on the results of using nanoimprint lithography as a potential means for replicating sawtooth grating masters. Our Nanoruler scanning beam interference lithography tool allows us to pattern large area gratings up to 300 mm in diameter. We also report on developments in grating assembly technology utilizing lithographically patterned and micromachined silicon metrology structures ("microcombs") that have achieved submicron assembly repeatability.

Original languageEnglish
Pages (from-to)271-282
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2004
EventOptics for EUV, X-Ray, and Gamma-Ray Astronomy - San Diego, CA, United States
Duration: 2003 Aug 42003 Aug 7

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Advances in reflection grating technology for Constellation-X'. Together they form a unique fingerprint.

Cite this