Subsections

• 14.10.1 Product PP1CHOPSIG: PHT-P1 chopped signal correction
• 14.10.2 Product PP2CHOPSIG: PHT-P2 chopped signal correction
• 14.10.3 Product PP3CHOPSIG: PHT-P3 chopped signal correction
• 14.10.4 Product PC1CHOPSIG: PHT-C100 chopped signal correction
• 14.10.5 Product PC2CHOPSIG: PHT-C200 chopped signal correction

14.10 Correction for Signal Losses in Chopped Mode

Description Parameter:	 none
Processing Level:	 SPD, AAR
Usage in processing:	 Section 7.5, 8.4.1
File Type:		 Binary FITS Table
Units:		 	 [V/s]
File Names:		 PP1CHOPSIG, PP2CHOPSIG, PP3CHOPSIG,
			 PC1CHOPSIG, PC2CHOPSIG

The signal difference between the on- and off-chopper plateaux is observed to be lower than the signal difference obtained from the same source-background position combination in staring or nodding mode. The effect is attributed to the detector transient responsivity behaviour of the detectors which underestimates the on-signal and overestimates the background signal. The calibration files contain for each detector the parameters necessary to correct the difference signal for the signal loss. The correction depends on the chopper dwell time and the value of the difference signal. The correction is implemented by a lookup table which for each chopper dwell time, lists the corrected signal as a function of the uncorrected signal.

14.10.1 Product PP1CHOPSIG: PHT-P1 chopped signal correction

Binary FITS table with record length 16. The record fields are:

Field	 Offset	Number	Type	Description
PP1CSCPT 0	1	I*4	Chopper dwell time: ,                       where  s, =1,8
PP1CSOOU 4	1	R*4	Uncorrected on-off source signal [V/s]
PP1CSOOC 8	1	R*4	Corrected on-off source signal [V/s]
PP1CSUNC 12	1	R*4	Uncertainty of the corrected on-off signal [V/s]

14.10.2 Product PP2CHOPSIG: PHT-P2 chopped signal correction

Same as PP1CHOPSIG, with `P1' in field keyword replaced by `P2'.

14.10.3 Product PP3CHOPSIG: PHT-P3 chopped signal correction

Same as PP1CHOPSIG, with `P1' in field keyword replaced by `P3'.

14.10.4 Product PC1CHOPSIG: PHT-C100 chopped signal correction

Binary FITS table with record length 20. The record fields are:

Field	 Offset	Number	Type	Description
PC1CSPIX 0	1	I*4	pixel
PC1CSCPT 4	1	I*4	Chopper dwell time: ,                       where  s, =1,8
PC1CSOOU 8	1	R*4	Uncorrected on-off source signal [V/s]
PC1CSOOC 12	1	R*4	Corrected on-off source signal [V/s]
PC1CSUNC 16	1	R*4	Uncertainty of the corrected on-off signal [V/s]

14.10.5 Product PC2CHOPSIG: PHT-C200 chopped signal correction

Same as PC1CHOPSIG, with `C1' in field keyword replaced by `C2'.