CDE CDR, September 14, 2004 Your Position, Your Name 1 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 1 GATS CIPS Calibration Review Aimee Merkel Bill McClintock

CDE CDR, September 14, 2004 Your Position, Your Name 2 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 2 GATS CIPS Science Measurement Requirements CDR Science Requirements Document Summary

CDE CDR, September 14, 2004 Your Position, Your Name 3 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 3 GATS CIPS Ground Calibration Summary Calibration Activities Unit level tests (detector components, assembled detector units, filters, lens systems) Camera level tests Preenvironmental instrument calibrations Environmental test Postenvironmental instrument calibrations Post spacecraft I&T calibrations Instrument Calibrations CCD characterization (read noise, dark current ) TDI (Time Delayed Integration: Nadir Cameras only) Wavelength Range Flat Field Field of View Linearity Distortion Polarization Off-axis response (Stray and scattered light performance) Spacecraft I&T calibrations Absolute sensitivity Postenvironmental Instrument checks (dark field) Point Spread Function Absolute sensitivity Focus Out of band rejection Light leaks Camera to camera alignment Camera to reference optical surface (ROS)

CDE CDR, September 14, 2004 Your Position, Your Name 4 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 4 GATS Calibration Measurement Summary Camera Field of ViewMinimum of 44º x 44º44º x 44º (1426 Pixels) LinearityMeasure to 95% full wellLinear to 3x10 3 DN Point Spread Function3 mrad (~0.075mm) FWHM0.077mm FWHM Polarization<10% (15% relative knowledge) Max 3% in corners 1% Accuracy Scattered Sunlight<10% of a cloud with A=10 -5 Declines 10 3 in 2 deg No Stray-light issues SensitivitySNR=2 a=10 -5 and AR=11SNR=5.2 a=10 -5 and AR=2 DistortionMeasure to 1% over field<1% Negligible Camera-to-Camera Alignment ±1º per camera On orbit re-calculation Flat Field1º accuracy1% or better RequirementMeasurement Cameras meet or exceed all performance requirements

CDE CDR, September 14, 2004 Your Position, Your Name 5 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 5 GATS Raw Image to Calibrated Image Process of converting raw image in data numbers (DN) to calibrated image (Level 1A data product) in units of Gary. (1 Gary= 1 x Albedo) Raw Image DN(i,j) Subtract Dark Dark (i,j) Divide out Flat Field FF Subtract stray light Stray (i,j) Account for Sensitivity of Camera. R inst (I,j,,T,HV)*F sun Correct for non-linearity N lin Place holder (no evidence of Stray light issues) Account for integration Period ∆t

CDE CDR, September 14, 2004 Your Position, Your Name 6 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 6 GATS Dark Image Dependence on CCD Temperature Electrical Offset and Dark Current vary differently with temperature. –Offset (set by electronics) Electrical offset added to image to provide a baseline signal to avoid negative readout. Applied after analog amplifier but before digitization. Has no non-linearity issues. –Dark Current Thermal noise that accumulates with image read out time (accumulates over rows). High Quality CCDs! Typical characteristics: Offset: ~90DN Dark Current: ~0.1 DN/sec or 3.2 e¯/sec

CDE CDR, September 14, 2004 Your Position, Your Name 7 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 7 GATS one orbit 1 st image Last image one orbit 1 st image Last image CIPS CCD Temperature Ranges CCD Temp only varies by 1ºC over orbit

CDE CDR, September 14, 2004 Your Position, Your Name 8 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 8 GATS Dark Image Dependence on CCD Temperature Interpolated over orbit Temperature

CDE CDR, September 14, 2004 Your Position, Your Name 9 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 9 GATS Linearity (N)

CDE CDR, September 14, 2004 Your Position, Your Name 10 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 10 GATS Camera Flat Field Pixel Normalized Flat Field Percentage of Max Signal Flat Field Requirement: 1% Accuracy Measured: Relative sensitivity across the 44º FOV~ 1% or better Repeatability of Flat images to ~ 0.1% Camera 0 Flat Field Variation from Pixel to Pixel due to: Photocathode variation Lens System: Cos 4  Integrating Sphere used to uniformly illuminate Camera FOV In-flight Image Calibration: Divide out normalized Flat Field from each image Pixel

CDE CDR, September 14, 2004 Your Position, Your Name 11 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 11 GATS Radiometric Sensitivity of Camera R(i,j) in units of DN/sec/Gary Still need to account for sensitivity dependence on Temperature (T) and High Voltage(HV)…

CDE CDR, September 14, 2004 Your Position, Your Name 12 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 12 GATS Correct Camera Sensitivity for T and HV

CDE CDR, September 14, 2004 Your Position, Your Name 13 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 13 GATS Calibrated Image Raw Image Data Number DN Calibrated Image (Albedo)

CDE CDR, September 14, 2004 Your Position, Your Name 14 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 14 GATS Calibrated Image Calibrated Image in Units of Garys Level 1A data product Processing test up to Level 1A data product successful. Ready for Launch!!!

CDE CDR, September 14, 2004 Your Position, Your Name 15 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 15 GATS Post Launch CIPS Calibration Overview In-Flight Calibration Task List: Absolute pointing knowledge established by viewing UV stars (0.2˚ knowledge requirement) Detector characterization Dark field Intensifier characterization Camera to camera alignment (science images) Absolute sensitivity by viewing UV stars. Flat Field images and Relative sensitivity over the FOV (‘clear field’ images) Stray and scattered light performance (shadow images) Light leaks (shutter test)

CDE CDR, September 14, 2004 Your Position, Your Name 16 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 16 GATS EXTRA SLIDES Extra Slides

CDE CDR, September 14, 2004 Your Position, Your Name 17 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 17 GATS CCD Acceptance Test Each flight CCD went through extensive acceptance testing with the flight electronics. At 3 different temperatures (25ºC, -10ºC, -40ºC) analyzed dark field –Number of Hot Pixels –Read Noise Number of electrons introduced (noise) when reading out of device. Effects all pixel values uniformly. –Dark Current Thermal noise that accumulates with image read out time. CIPS CCD has a 17 sec readout time, the dark current accumulates over rows. For example: First row read out has less dark current than the last row read out. Reported as electrons/second –Offset (set by electronics) Signal readout from CCD when not exposed to light. Accommodates temporal shifts in electronics, temperature stability and read noise. Avoids negative readout. –Photon Transfer Checks the full well, offset, gain, linearity of the CCD.

CDE CDR, September 14, 2004 Your Position, Your Name 18 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 18 GATS CCD Acceptance Test High Quality CCDs! Typical characteristics: Hot Pixels: < 0.07% Read Noise: ~38 Electrons Offset: ~90DN Dark Current: ~0.1 DN/sec or 3.2 e¯/sec Each CCD is 2048 X 2048 pixels. Only 1360 x 1360 pixels are used. Dark images are used to characterize the CCDs. CCD 01 in Camera 0 I&T calibration: Built up instrument Read Noise: ~ 45 Electrons Integration Period (s) Data Number (DN)

CDE CDR, September 14, 2004 Your Position, Your Name 19 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 19 GATS Camera Field of View 1447 pixels 44º = 1426 Pixels Field of View: ~44º square for all cameras Requirement: Minimum of 44º square

CDE CDR, September 14, 2004 Your Position, Your Name 20 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 20 GATS Linearity Camera Linearity: Linear ~ 3x10 3 DN Completely nonlinear by 10 4 DN Requirement: Measure linearity to 95% full well Linearity measured using the integrating sphere. Integration period incremented until saturation achieved.

CDE CDR, September 14, 2004 Your Position, Your Name 21 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 21 GATS Camera Distortion Measure: Took image of grid in clean room Positioned 10 feet away to fill the 44º FOV Looked at linearity of lines across FOV Requirement: Measure to 1% over the field

CDE CDR, September 14, 2004 Your Position, Your Name 22 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 22 GATS Camera Polarization Polarization: Max 3% in Corners Accuracy ~ 1% Polarization effects are negligible Requirement: Less than 10% 5% Accuracy Percent Polarization Linear polarization: Measured both Perp and Para response using a star source and Glan-Taylor linear polarizer. Response measured at 21 discrete points on the detector as displayed below.

CDE CDR, September 14, 2004 Your Position, Your Name 23 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 23 GATS Camera Composite PY MY MXPX SUN

CDE CDR, September 14, 2004 Your Position, Your Name 24 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 24 GATS UV Bandpass Wavelength (nm) Transmission Ultraviolet Bandpass: 265nm ± 10nm In-band Transmission: 30% Measured Filter

CDE CDR, September 14, 2004 Your Position, Your Name 25 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 25 GATS Near Field Off Axis Response Near Field Off Axis Response Declines ~ 10 3 in 2 Degrees

CDE CDR, September 14, 2004 Your Position, Your Name 26 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 26 GATS Radiometric Calibration Radiometric sensitivity is measured using a NIST- traceable 1-KW quartz-halogen standard lamp and a reflectance screen

CDE CDR, September 14, 2004 Your Position, Your Name 27 GATS AIM Science Team Meeting January 23-24, 2007 CIPS Calibration Review, Aimee Merkel, Bill McClintock 27 GATS Radiometric Calibration Illuminated Screen+RoomBlocked ScreenDifference Measurement sequence repeated 20 Times at 4 high voltages Signal ~ exponential function of HV SNR varies by ~ 10% for HV> 700 volts