The SPI instrument has been launched on-board the INTEGRAL observatory on
October 17, 2002. SPI is a spectrometer devoted to the sky observation in the
20 keV-8 MeV energy range using 19 germanium detectors. The performance of the
cryogenic system is nominal and allows to cool the 19 kg of germanium down to
85 K with a comfortable margin. The energy resolution of the whole camera is
2.5 keV at 1.1 MeV. This resolution degrades with time due to particle
irradiation in space. We show that the annealing process allows the recovery of
the initial performance. The anticoincidence shield works as expected, with a
low threshold at 75 keV, reducing the GeD background by a factor of 20. The
digital front-end electronics system allows the perfect alignement in time of
all the signals as well as the optimisation of the dead time (12%). We
demonstrate that SPI is able to map regions as complex as the galactic plane.
The obtained spectrum of the Crab nebula validates the present version of our
response matrix. The 3 σ sensitivity of the instrument at 1 MeV is 8
10−7ph⋅cm−2⋅s−1⋅keV−1 for the continuum and 3
10−5ph⋅cm−2⋅s−1 for narrow lines.Comment: 10 pages, 18 figures, accepted for publication in A&A (special
INTEGRAL volume