THE WEEKLY DETECTOR Taormina, Italia June, 2005 € 0.00 The Nerds are Back In Town !! This Week’s Forecast Clear Skies Seeing 0.4” Some Ash Warm Seas Detector Testing Methodologies For Large Focal Planes P. C. Moore and G. Rahmer Subtle change of paradigmFocal planes Linking detector performance to science objectives It is a familiar saying that in science, asking a question usually provides more questions than answers. In this way, the questions we asked yesterday have led us to ask new questions today that require ever increasing contributions of social, political, and capital investment to answer. To this end, a subtle change of paradigm is in process with regard to the methodology of developing astronomical instrumentation. Historically instrumentation was designed specifically for an institutional telescope, or a small group of telescopes, and with a relatively wide range of application for general application to astronomy. With relevance to this paper, this often meant designing an instrument to accommodate the convolution of a new or enhanced detector technology with the current demands of a national group of scientists. Today we see a trend towards large collaborations to supply the scientific, engineering, and capital investment required to provide the instrumentation needed to supply an answer to perhaps just one or two specific questions. In this new paradigm, the science objectives have clear priority; the instrument being designed specifically for these requirements, and often, a telescope being built to accommodate the instrument. By analyzing the science tradeoffs that will occur when detector performance is less than (or better than) the instrument specification, a figure of merit can be established for each tested detector. This will allow an unambiguous comparison of different detectors and detector technologies to be made and reflect the degree of suitability of any particular detector to the instrument science objectives. To derive the figure of merit for each detector, metrics are obtained from direct measurements of a detectors performance, which are then normalized to a typical operational model of an instrument observational unit. Five metrics are considered in the figure of merit. These are cadence (i.e. Observed sky / time), observed optical quality, observational depth, photometric accuracy, and observatory efficiency. Each metric for a particular detector is calculated using measured detector parameters. The use of large detector mosaics to support future instrumentation poses new demands on the timeliness and rigor of detector testing procedures. Ideally, the characterization and selection of detectors for any particular new instrument should not appear as a critical path in the project. Committing to a large lot run of devices is expensive and deserves deep analysis of the factors that affect scientific tradeoff, developmental risk, and delivery schedules. We propose a methodology that involves incorporation of the elements of detector testing at the very beginning of the instrument requirement definition process: In this way the selection of detectors to provide the maximum science potential can be assured and audited.

THE WEEKLY DETECTOR Taormina, Italia June, 2005 € 0.00 The Nerds are Back In Town !! This Week’s Forecast Clear Skies Seeing 0.4” Some Ash Warm Seas Detector Testing Methodologies For Large Focal Planes P. C. Moore and G. Rahmer Budget Requirements Science Requirements Time / Resource Availability Detector Availability Pixel Size ! Well Depth What’s For Lunch

THE WEEKLY DETECTOR Taormina, Italia June, 2005 € 0.00 The Nerds are Back In Town !! This Week’s Forecast Clear Skies Seeing 0.4” Some Ash Warm Seas Detector Testing Methodologies For Large Focal Planes P. C. Moore and G. Rahmer Subtle change of paradigm New Detector Science New Instrument New Question Engineering New Question Science New Instrument New Question Engineering

THE WEEKLY DETECTOR Taormina, Italia June, 2005 € 0.00 The Nerds are Back In Town !! This Week’s Forecast Clear Skies Seeing 0.4” Some Ash Warm Seas Detector Testing Methodologies For Large Focal Planes P. C. Moore and G. Rahmer Focal planes Some Current Questions Require Subtle change of paradigm

THE WEEKLY DETECTOR Taormina, Italia June, 2005 € 0.00 The Nerds are Back In Town !! This Week’s Forecast Clear Skies Seeing 0.4” Some Ash Warm Seas Detector Testing Methodologies For Large Focal Planes P. C. Moore and G. Rahmer Subtle change of paradigmFocal planes Linking detector performance to science objectives Cosmetics …. Fill Factor Hard Metrics Measured Detector Characteristics Science Requirements

Characterization Lab established to prove concept North Detector Lab begins to take shape, South to follow soon. New dewar design and serialization key to reduction in characterization time. THE WEEKLY DETECTOR Taormina, Italia June, 2005 € 0.00 The Nerds are Back In Town !! This Week’s Forecast Clear Skies Seeing 0.4” Some Ash Warm Seas Detector Testing Methodologies For Large Focal Planes P. C. Moore and G. Rahmer

THE WEEKLY DETECTOR Taormina, Italia June, 2005 € 0.00 The Nerds are Back In Town !! This Week’s Forecast Clear Skies Seeing 0.4” Some Ash Warm Seas Detector Testing Methodologies For Large Focal Planes P. C. Moore and G. Rahmer Subtle change of paradigmFocal planes Linking detector performance to science objectives It is a familiar saying that in science, asking a question usually provides more questions than answers. In this way, the questions we asked yesterday have led us to ask new questions today that require ever increasing contributions of social, political, and capital investment to answer. To this end, a subtle change of paradigm is in process with regard to the methodology of developing astronomical instrumentation. Historically instrumentation was designed specifically for an institutional telescope, or a small group of telescopes, and with a relatively wide range of application for general application to astronomy. With relevance to this paper, this often meant designing an instrument to accommodate the convolution of a new or enhanced detector technology with the current demands of a national group of scientists. Today we see a trend towards large collaborations to supply the scientific, engineering, and capital investment required to provide the instrumentation needed to supply an answer to perhaps just one or two specific questions. In this new paradigm, the science objectives have clear priority; the instrument being designed specifically for these requirements, and often, a telescope being built to accommodate the instrument. By analyzing the science tradeoffs that will occur when detector performance is less than (or better than) the instrument specification, a figure of merit can be established for each tested detector. This will allow an unambiguous comparison of different detectors and detector technologies to be made and reflect the degree of suitability of any particular detector to the instrument science objectives. To derive the figure of merit for each detector, metrics are obtained from direct measurements of a detectors performance, which are then normalized to a typical operational model of an instrument observational unit. Five metrics are considered in the figure of merit. These are cadence (i.e. Observed sky / time), observed optical quality, observational depth, photometric accuracy, and observatory efficiency. Each metric for a particular detector is calculated using measured detector parameters. The use of large detector mosaics to support future instrumentation poses new demands on the timeliness and rigor of detector testing procedures. Ideally, the characterization and selection of detectors for any particular new instrument should not appear as a critical path in the project. Committing to a large lot run of devices is expensive and deserves deep analysis of the factors that affect scientific tradeoff, developmental risk, and delivery schedules. We propose a methodology that involves incorporation of the elements of detector testing at the very beginning of the instrument requirement definition process: In this way the selection of detectors to provide the maximum science potential can be assured and audited.