Chandra High Energy Transmission Grating (HETG)

Providing the best spectral resolution in X-rays ever

X shaped visualization of HETG dispersed photons in Chandra

About the HETG

Chandra and HETG in
		  front of Supernova

HETG is the High-Energy Transmission Grating on the Chandra X-ray satellite. It consists of two sets of gratings, each with different period: The Medium Energy Grating (MEG) and the High Energy Gratings (HEG). Both gratings are mounted on a single support structure and therefore are used together. The HETG is described in detail in a chapter in the Chandra Proposers' Observatory Guide.

The HETG was designed and build at MIT by the group of HETG Principal Investigator Prof. Claude R. Canizares.

Calibration

Current Calibration

Information about the current calibration of the HETG can be found at the main CXC calibration web page.

XRCF

Before launch, all instruments on Chandra were extensively tested on the ground in the X-ray calibration facility (XRCF). Most of this data is only of historical interest at this point, but occasionally, we might have to look back to the ground calibration data.

Reports

History

The HETG was designed, built, and tested at MIT in Cambridge, MA, USA. The membrane-supported gold gratings that disperse the light were developed and made in the Space Nanotechnology Laboratory (formerly known as the Space Microstructures Laboratory) in Building 37. Gratings where then tested on an X-ray beamline in building NE-80.

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Vibration isolation table where grating patterns are written using interference lithography at the Space Nanotechnology Laboratory
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Thin film stress measuring tool at the Space Nanotechnology Laboratory
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X-ray fluorescence thin-film measuring tool at the Space Nanotechnology Laboratory
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Photo-elastic modulator grating alignment tool at the Space Nanotechnology Laboratory
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Class 100 inspection station at the Space Nanotechnology Laboratory
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Gold electroplating hood at Space Nanotechnology Laboratory
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Reactive-ion etch plasma tool at Space Nanotechnology Laboratory
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Rotoetch acid-spin wafer etching tool at Space Nanotechnology Laboratory
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Medium-Energy Grating (MEG) facet in its holder
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top: Chris Pak standing in front of HETG Support Structure (HESS); bottom: HESS engineering model after machining, 6/95
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HETG Mass model before delivery to Kodak, 7/95
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HETG Mass model with covers and alignment reference mirror, 7/95
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HETG Engineering model with grating surrogates installed, 12/95
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HETG Engineering model during vibration testing, 12/95
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Completed Flight Model HETG, 10/96
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standing: Prof. Hank Smith, Bob Sisson, unknown, Mark Schattenburg, Robert Fleming; front: Patrick Hindle, Jane Prentiss, Jeanne Porter, Rich Aucoin, 10/96
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HETG facet inspection, 12/96
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HETG on lift mechanism, 12/96
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HETG near work platform and HRMA, 12/96
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HETG installation, 12/96
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View of aft structure (LETG in foreground), 12/96

Instrument Publications

Publications about the HETG are collected in this ADS library, use the Chandra Bibliography Search to search for publications using data from the HETG.

An annual report of the HETG status and science highlights is given in the Chandra newsletter.