HEAO 1 A4 Spectra
The UCSD/MIT Hard X-Ray and Low-Energy Gamma-Ray Instrument, A4, was flown on the HEAO 1 satellite, between August 1977 until January 1979. The experiment consisted of a collection of collimated sodium iodide scintillators, two of which the Low Energy detectors (LED, LED-3 and LED-6), were optimized for the lower energy part of the hard X-ray range between 13 to 180 keV. The first 6-months of mission were dedicated to an all-sky scan after which a pointing phase started. In pointing mode the A4-LED instrument look axis was kept in a 1 deg dead band centered on the target position. Instead in the "ping-pong" mode the look axis was regularly alternated with a secondary target a few degrees away, usually for background determination. This database table accesses the spectra (and associated files) obtained from the A4-LED detectors in the ping-pong mode. This is a service provided by NASA HEASARC .
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Complete Metadata
| @type | dcat:Dataset |
|---|---|
| accessLevel | public |
| bureauCode |
[ "026:00" ] |
| contactPoint |
{ "fn": "HEASARC Help Desk", "@type": "vcard:Contact", "hasEmail": "mailto:andrew.ptak@nasa.gov" } |
| description | The UCSD/MIT Hard X-Ray and Low-Energy Gamma-Ray Instrument, A4, was flown on the HEAO 1 satellite, between August 1977 until January 1979. The experiment consisted of a collection of collimated sodium iodide scintillators, two of which the Low Energy detectors (LED, LED-3 and LED-6), were optimized for the lower energy part of the hard X-ray range between 13 to 180 keV. The first 6-months of mission were dedicated to an all-sky scan after which a pointing phase started. In pointing mode the A4-LED instrument look axis was kept in a 1 deg dead band centered on the target position. Instead in the "ping-pong" mode the look axis was regularly alternated with a secondary target a few degrees away, usually for background determination. This database table accesses the spectra (and associated files) obtained from the A4-LED detectors in the ping-pong mode. This is a service provided by NASA HEASARC . |
| distribution |
[ { "@type": "dcat:Distribution", "format": "HTML", "mediaType": "text/html", "downloadURL": "https://heasarc.gsfc.nasa.gov/W3Browse/all/a4spectra.html" }, { "@type": "dcat:Distribution", "format": "BIN", "mediaType": "application/octet-stream", "downloadURL": "https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=a4spectra&" } ] |
| identifier | ivo://nasa.heasarc/a4spectra |
| keyword |
[ "__" ] |
| landingPage | ivo://nasa.heasarc/a4spectra |
| license | https://www.usa.gov/government-works |
| modified | 2026-09-22 |
| programCode |
[ "026:000" ] |
| publisher |
{ "name": "High Energy Astrophysics Science Archive Research Center", "@type": "org:Organization" } |
| theme |
[ "Astrophysics" ] |
| title | HEAO 1 A4 Spectra |
