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System Performance Metrics and Current Performance Status

System Performance Metrics and Current Performance Status. George Angeli. Performance Metrics. *. Updated estimates. Calibration update in - progress. Integrated É tendue. Basic definition Extended definition Sensitivity Integrated étendue

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System Performance Metrics and Current Performance Status

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  1. System Performance Metrics and Current Performance Status George Angeli

  2. Performance Metrics * Updated estimates Calibration update in-progress

  3. Integrated Étendue • Basic definition • Extended definition • Sensitivity • Integrated étendue • Fill Factor (fF) - accounts for losses in the field due to masks, bad pixels, charge stops • Sensitivity Factor (fS) – accounts for sensitivity losses or gains due to throughput, image quality, read noise • Observing Efficiency Factor (fO) – accounts for losses or gains in open shutter efficiency over the entire survey

  4. Sensitivity Factor • Not allocated - driven by allocable Technical Performance Metrics: • Image Quality • Throughput • Read noise • For each band: • Overall fs as time weighted sum

  5. Evolution of Image Depth Reserve Reserve in LSR above SRD Minimum Specification P R O P O S E D Sensitivity factor relative to SRD minimum specs: 1.69 1.83 See Chuck’s presentation for details

  6. Image Depth Dependencies • For each band: Image Quality Throughput and read noise r band Change since JIM Review

  7. Image Quality Error Budget Telescope reserve: 105 mas Camera reserve: 102 mas See Bo’s presentation for details of meeting this budget milliarcsecond (mas)

  8. Evolution of IQ System Reserve milliarcsecond (mas) Charge diffusion contribution estimate reduced before FDR from 259 mas to 186 mas

  9. System Behavior PSF size and shape

  10. Integrated System Model PSF size and shape Currently ZEMAX Preferably PhoSim

  11. Input Parameters (Perturbations) • Deterministic effects • Optical design residual errors, • Diffraction effects due to the finite aperture and pupil obscuration, • Deterministic effects randomized by environmental and operational parameters • Mirror support print through and lens gravitational deformations randomized through telescope zenith angle • Thermal deformations of optical surfaces and support structures randomized through ambient and local temperature • Random processes • Dome and mirror seeing • Local actuator and sensor noise and drift (non-optical sensors) • Counting statistics • CCD sensor effects (solid state effects: diffusion, field dependencies, penetration depth, QE variations) • WFS measurement, estimation, and control errors • Material, fabrication, and installation errors; these become deterministic once the “as built” system is available

  12. Output Parameters (Metrics) • FWHM across the field • Ellipticity across the field • Area weighted mean of 31 samples • Diffraction (FFT) PSF • Also track geometric PSF derived from spot RMS

  13. Environmental Conditions • Fiducial atmospheres (3) • Scaled to 0.44”, 0.6”, and 0.8” FWHM seeing on the aperture of LSST. • Zenith angle range of 0˚- 65˚ • Statistical distribution derived from “standard” OpSim simulations. • Temperature and pressure ranges as defined in the OSS as Normal Operating Conditions. • The temperature inside enclosed volumes, like the Camera, needs to be estimated from these environmental parameters. • The expected temperature range of the detector, with assumed statistics

  14. Future Work • Transition the optical kernel to PhoSim • Include missing instrumental perturbations • Most prominently sensor effects • In the process of implemented in PhoSim • Improve AOS control laws and performance • Establish a configuration adequate for science simulations • Linked or emulated AOS

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