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.