As the main detector of GECAM satellite payload with large area and field of view and high detection efficiency, GRD can be used for triggering and positioning of gamma-ray burst and observing the light-curve and energy spectrums. Its main functions are as follows:

1.To conduct all-sky monitoring on gamma-ray burst within the wave band from X-ray to gamma ray (covers the energy range from 8 to 2000 keV);

2.To quickly trigger and position gamma-ray burst in the field of view;

3.To measure the light-curve and energy spectrums of various gamma-ray bursts;

4.To detect gravitational wave gamma-ray burst in combination with ground gravitational wave detectors;

5.To identify gamma-ray burst and charged particle burst together with CPD payload.

The characteristic is shown below.



Detection   energy range

8 keV– 2 MeV

Detection area

 > 40 cm2 (for   each GRD)


 < 4 μs   (normal event)
   ~ 70 μs (overflow event)

Energy   resolution

 < 18%@59.5 keV

Detection   efficiency for Gamma-rays

 > 60%@8 keV

The GRD onboard the GECAM satellite is mainly composed of the encapsulated LaBr3 crystal unit, SiPM array, pre-amplification electric circuit electronics system and mechanical structure, its internal structure is shown below. For more details, refer to

Figure: Schematic diagram of GRD

Figure: SiPM array of GRD.

Figure: The detector energy spectrums of GRD at simulated gamma ray incident energies of 8 keV (a), 59.5 keV (b), 662 keV (c), and 1 MeV (d), respectively