ISGRI

In OSA10 the following corrections to the pulse height gains and offsets have been applied (see Section 12.1):

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For E 50 keV the gain is modeled with a linear function

The parameters needed to describe the gain for E 50 keV are hard-coded in OSA (ibis_isgr_energy and ii_shadow_build).

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For E 50 keV the pulse height gain and offset are modeled as a function of the rise time (rt) and revolution number:

The values for the gain and offset as a function of the rise time are delivered as calibration files in two new IC tables, ISGR_GAIN_MOD and ISGR_OFF2_MOD.

Table 34: Content of ISGR-GAIN-MOD Data Structure

Column Name	Description
PAR1	Parameter 1 for energy gain correction
PAR2	Parameter 2 for energy gain correction

Table 35: Content of ISGR-OFF2-MOD Data Structure

Column Name	Description
PAR1	Parameter 1 for energy offset correction
PAR2	Parameter 2 for energy offset correction
PAR3	Parameter 3 for energy offset correction

To perform a rise-time correction for each raw ISGRI event, the Rise-Time correction table is used (ISGR-RISE-MOD Data Structure, see details in Table 36). This table is composed of NUM_ENER lines, giving for each incident energy the correction factor corr for a given value of the rise-time.

Table 36: Content of ISGR-RISE-MOD Data Structure

Column Name	Description
ENERGY	Energy at which the gain-offset relationship is measured
CHANNEL	Channel at which the gain-offset relationship is measured
CORR	Rise-time correction for a given rise-time value (0-127)

The rise-time itself and the gain offset are kept at the ISGR-OFFS-MOD Data Structure.

Table 37: Content of ISGR-OFFS-MOD Data Structure

Column Name	Description
AGAIN	Amplitude Gain
AOFFSET	Amplitude Offset
RTGAIN	Risetime Gain
RTOFFSET	Risetime Offset
PIXTYPE	Pixel type