Overview of the ACS Calibration Plan Items

	Test Item	Detectors	Environment	Stimulus

1. Detector Properties

1.1	CCD optimization	HRC, WFC	Ambient	CCD bench
1.3	EPER and FPR CTE vs temperature and illumination	HRC, WFC	Any	Internal FF
1.4	Gain, linearity, saturation	HRC, WFC	Any	Internal FF
1.9	Detector defects	HRC, WFC	Any	External/Internal FF
1.2	Dark count rate vs temperature	HRC, WFC, SBC	TV	None
1.5	Bias level vs gain, amplifier	HRC, WFC	Any	None
1.6	Read noise vs gain, amplifier	HRC, WFC	Any	None
1.8	Minimum stable CCD temp., TEC char.	HRC, WFC	TV	None
1.7	Linearity: point and diffuse sources	All	Any	RAS/Cal, FF

2. Shutter Performance

2.1	Shutter accuracy, repeatability	HRC, WFC	Ambient	RAS/HOMS, External FF
2.2	Shutter shading	HRC, WFC	Ambient	RAS/HOMS, External FF

3. Geometric Calibration

3.1	FOV location in V2/V3	HRC, WFC	Ambient	RAS/HOMS
3.2	Plate scale, orientation	HRC, WFC	Ambient	RAS/HOMS
3.3	Distortion	HRC, WFC	Ambient	RAS/HOMS

4. PSF Characterization

4.1	Image quality (EE) vs field position	HRC, WFC	Ambient	RAS/HOMS
4.1	Image quality (EE) vs field position	SBC	Purge	RAS/Cal
4.2	Corrector performance verification	HRC, WFC	Ambient	RAS/HOMS, RAS/Cal
4.3	Coronagraph performance	HRC	Ambient	RAS/HOMS
4.4	Image stability	HRC+Coronagraph	TV	External FF
4.5	PSF wings, halo measurements.	HRC, WFC	Ambient	RAS/Cal

5. Photometric Calibration at Field Center

5.1	Throughput at field center	HRC, WFC	Ambient	RAS/Cal
5.2	Throughput stability at field center	HRC, WFC	Ambient	RAS/Cal
5.3	Out-of-band rejection	SBC	Ambient	RAS/Cal
5.4	UV filter red blocking	HRC, WFC	Ambient	RAS/Cal

6. Photometric Calibration over Field

6.1	Flat field uniformity	HRC, WFC	Ambient	RAS/HOMS, External FF
6.1	Flat fields, uniformity	SBC	TV	External UV FF
6.2	Flat field stability	All	TV	External FF
6.3	Fringing	HRC, WFC	Ambient	RAS/HOMS, External FF
6.4	Ramp filter FF strategy evaluation	HRC, WFC	Ambient	RAS/HOMS, External FF
6.5	Internal cal. system verification	All	Any	Internal FF

7. Dispersion

7.1	Prism/grism dispersion vs field position	HRC, WFC	Ambient	RAS/Cal
7.1	Prism dispersion vs field position	SBC	Purge	RAS/Cal

8. Ramp Filter Characterization

8.1	Ramp filter wavelength vs position	HRC, WFC	Ambient	RAS/HOMS
8.2	Filter wheel repeatability	HRC, WFC	Ambient	None

9. Polarimetric Calibration

9.1	Instrumental polarization	HRC, WFC	Ambient	RAS/HOMS, RAS/Cal, External FF
9.2	Polarization efficiency	HRC, WFC	Ambient	RAS/Cal+Polarimeters
9.3	Polarization angle	HRC, WFC	Ambient	RAS/Cal+Polarimeters
9.4	Relative image displacement	HRC, WFC	Ambient	RAS/Cal

10. Stray Light Characterization

10.1	Filter/window ghosts	HRC, WFC	Ambient	RAS/HOMS
10.2	Mask reflections	HRC, WFC	Ambient	RAS/HOMS
10.3	WFC gap behavior	WFC	Ambient	RAS/HOMS
10.4	Baffle efficacy	HRC, WFC	Ambient	RAS/HOMS

11. Flight Software (FSW) Verification

11.1	Exercise all FSW modes (functionals)	All	Ambient	Any
11.2	Coronagraphic spot repeatability	HRC	Ambient	RAS/Cal
11.3	TA verification	HRC	Ambient	RAS/Cal
11.4	Bright object protection	SBC	Ambient	RAS/Cal

Note : The environments are thermal vacuum (TV), ambient, or dry N₂ purge. The external stimuli are RAS/HOMS, RAS/Cal, or any other light source at the ACS aperture. Either broad-band ("white light") or monochromatic illumination is used depending on the calibration item. The internal illumination is provided by the tungsten and D₂ lamps.

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