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 .
Complete Metadata
| @type | dcat:Dataset |
|---|---|
| accessLevel | public |
| bureauCode |
[
"026:00"
]
|
| contactPoint |
{
"fn": "Tess Jaffe",
"@type": "vcard:Contact",
"hasEmail": "mailto:tess.jaffe@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",
"title": "Data Information (HTML)",
"format": "HTML",
"mediaType": "text/html",
"downloadURL": "https://heasarc.gsfc.nasa.gov/W3Browse/all/a4spectra.html"
},
{
"@type": "dcat:Distribution",
"title": "Data Information (Unknown Format)",
"format": "BIN",
"mediaType": "application/octet-stream",
"downloadURL": "https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=a4spectra&"
}
]
|
| identifier | ivo://nasa.heasarc/a4spectra |
| keyword |
[
"na"
]
|
| landingPage | https://heasarc.gsfc.nasa.gov/W3Browse/all/a4spectra.html |
| modified | 2026-02-10 |
| programCode |
[
"026:000"
]
|
| publisher |
{
"name": "High Energy Astrophysics Science Archive Research Center",
"@type": "org:Organization"
}
|
| theme |
[
"Astrophysics"
]
|
| title | HEAO 1 A4 Spectra |
