The instrument characteristics required for the processing of the raw ISOPHOT data into calibrated products are stored in calibration files which are referred to as ``Calibration G'' or ``Cal G'' files. All Cal G files are in FITS format. The Cal G files are updated depending on the outcome of the dedicated calibration observations.

In the Table 5.1 the types of Cal G information mentioned in this chapter are listed together with references to the full descriptions elsewhere in this manual. A complete description of all Cal G files can be found in chapter 13.

**Table 5.1:** Cal G files related to the parameters described in this chapter
parameter	Description	full description
P_fcs^f(h)	FCS power calibration tables	section 13.10
R_det	Default detector responsivities	section 13.11
f^f_PSF	Point Spread Function factors	section 13.15
${\alpha}^f(a)$	Inhomogeneous FCS illumination of PHT-P	section 13.13
${\Gamma}^{f}(i)$	Array Illumination by FCS	section 13.12
${\chi}^f(i)$	Wavelength dependent detector flat fields	section 13.14
C1^f	Conversion from in-band power to flux density	section 13.17
S^det_dark	Default dark signals	section 13.7
${\Omega}_{eff}^f$	Effective solid angles of apertures and pixels	section 13.18
C_s,pnt(i), C_s,ext(i), ${\lambda}(i)$	PHT-S wavelength and signal calibration	section 13.16
k_f	Colour corrections	section 13.19

Cal G files should not be confused with the ISOPHOT dataproducts related to the FCS measurements which are part of all PHT AOTs except P40. These products are called ``Calibration A'' or ``Cal A'' files. Cal A files are generated at the SPD processing level. Among other data items the Cal A products contain the signal per chopper plateau. The FCS heating power as well as the expected in-band power is provided so that the responsivity of the detector close to the time of the target measurement can be obtained. The derived responsivity together with its uncertainty for each detector pixel has been included in the FITS header of the related SPD product.

5.7 Calibration files

5.7.1 Calibration G files

5.7.2 Calibration A files