The GRIT array is composed of :
- 2 rings of trapezoidal telescopess in the forward and backward direction
- 1 ring of square telescopes at 90 degrees
- 2 annular detectors in the most forward and backward angles
Each telescope consist of :
- one 500 um thick first layer of nTD (neutron transmutation doped) type Double Sided Stripped Silicon detectors (DSSSD) with 128 strips on each side
- one or two (in the forward hemisphere) 1.5 mm thick DSSSD with larger pitch (32 strips on each side).
The thin trapezoidal and square prototypes have been developed and fully tested on a test bench. The energy resolution is of about 50 keV all strips summed.
A thick (1.5mm) square detector has also been developed and tested with an alpha source. The obtained energy resolution is of about 70 keV (FWHM).