The SPI telescope has been designed to provide at the same time a medium angular resolution and an excellent energy resolution in the range 20 keV - 8 MeV. The main characteristics of the instrument are given in Table 1. The imaging capabilities are limited by the fact that SPI consists of only 19 detectors (pixels), and that the data are strongly background dominated. To help distinguishing between source and background photons, the number of ``measurements'' is increased by dithering the whole spacecraft around the target of interest. A typical observation is thus split into a number of ``pointings'' whose attitude differ by about 2 degrees, see Section ``Strategies of scientific Observations'' in the `` Introduction to the INTEGRAL Data Analysis [1])".
| Energy range | 20 keV - 8 MeV |
| Energy resolution (FWHM) | 2.35 keV at 1.33 MeV |
| Detector area | 500cm |
| Field-of-View: | 16 16 (fully coded) |
| 35 35 (zero coded) | |
| Angular resolution | 2.8 for point sources. |
| Point source positioning | 1.3 for point sources |
| (depending on point source intensity). | |
| Continuum Sensitivity | 1.1 10 ph/cm /s/keV at 1 MeV |
| Narrow line Sensitivity | 5. 10 ph/cm /s at 1 MeV |
| Timing accuracy | 160 s |