BATSE - the all-sky monitor for Compton is designed to detect
gamma-ray bursts and search the sky for other transient emission.

BATSE - the all-sky monitor for Compton is designed to detect gamma-ray bursts and search the sky for other transient emission.

BATSE the Burst and Transient Source Experiment -is the all-sky monitor for Compton. This experiment uses eight independent detectors, one at each corner of the satellite, resulting in a continuous view of those parts of the sky not blocked by the Earth. The individual modules use scintillators as the active detection element. Scintillators are large crystals, in the BATSE case made of sodium iodide, which convert the energy of the


gamma ray into visible light. Photomultipliers viewing the crystal then detect the visible photons. The strength of the resulting electronic signal is the record of the gamma-ray energy. BATSE can detect photons in the range of about 20 keV to 1 MeV. This instrument has the capability to detect many gamma rays in small periods of time, allowing scientists to study the temporal structure of gamma-ray bursts. While an individual BATSE module cannot record the direction of the incident gamma rays, the relative strengths of the burst signal in each module result in an approximate triangulation of the burst position. The origin of gamma-ray bursts remains the longest unsolved mystery in modern astronomy. Hundreds of gamma-ray bursts were detected prior to the launch of the Compton Gamma Ray Observatory, but few clues to their nature have been forthcoming. One of BATSE's primary objectives is to study these sources by mapping their positions on the sky and by measuring their

brightness, spectra and temporal development. Their time profiles are particularly enigmatic, lasting a few tens of milliseconds to hundreds of seconds, each burst exhibiting a unique and complex evolution of brightness with time. Since Compton's launch, approximately one gamma-ray burst per day has been detected by BATSE. In addition, BATSE has the capability of performing long-term monitoring of other types of gamma-ray sources. Many objects emit photons in the same energy band as gamma-ray bursts, including accreting neutron stars and black holes, some radio pulsars and active galaxies. BATSE provides a valuable capability for detecting changes in flux associated with these objects over a large range of timescales and helps scientists understand the mechanisms responsible for their high-energy emission. BATSE also uses its gamma-ray burst design capabilities to provide valuable data on the hard x-ray emission from solar flares.
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