A high sensitivity payload for balloon-borne hard X-ray astronomy

A new balloon-borne Large Area Scintillation counter Experiment (LASE) has been built to detect ultrafast variations in the flux of X-ray sources in hard X-ray band upto 200 keV. Presently, the instrument consists of three modules, each made of a 3 mm and a 30 mm NaI(Tl) crystals, arranged in a back-to-back geometry and having an effective area of 400 cm2. In final configuration, the payload will have an area of 2400 cm2. The data is spectrum analyzed in 128 channels between 20 and 200 keV and each event is time-tagged to an accuracy of 25 μs. The estimated sensitivity of the telescope is ∼10−6 cm−2 s−1 keV−1 for 3 h of source observation. The detector design, background rejection, on-board trigger system, attitude control parameters and the flight performance are described briefly.