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.
Parameters | Value |
Detection energy range | 8 keV– 2 MeV |
Detection area | > 40 cm2 (for each GRD) |
Dead-time | < 4 μs (normal 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 https://link.springer.com/article/10.1007/s41605-021-00289-y.
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