In flight performance and first results of FREGATE
  The gamma-ray detector of HETE-2, called FREGATE, has been designed to detect gamma-ray bursts in the energy range [6-400] keV. Its main task is to alert the other instruments of the occurrence of a gamma-ray burst (GRB) and to provide the spectral coverage of the GRB prompt emission in hard X-rays and soft gamma-rays. FREGATE was switched on on October 16, 2000, one week after the successful launch of HETE-2, and has been continuously working since then. We describe here the main characteristics of the instrument, its in-flight performance and we briefly discuss the first GRB observations. 
J-L. Atteia, M. Boer, F. Cotin, J. Couteret, J-P. Dezalay, M. Ehanno,   J. Evrard, D. Lagrange, M. Niel, J-F Olive, G. Rouai...