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Thermal Analysis. Thermal Analysis. Thermal Analysis FEA Model Schematic. Thermal Analysis. NICI Cryogenic Requirements Maintain optics and baffling at a temperature that will result in the background seen by the detector, emitted by the optics and baffles, is below 50% of the sky background.
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Thermal Analysis NICI Cryogenic Requirements • Maintain optics and baffling at a temperature that will result in the background seen by the detector, emitted by the optics and baffles, is below 50% of the sky background. • Maintain the two detectors at the desired operating temperature of 30-35 K to within +- 0.1 K • Have a cooldown time and a warm up time of less than two days. • Use Closed Cycle Coolers
Thermal Analysis Temperature goals • Cold Structure warmest temperature 75 K • Detector operating temperature 30 K • Radiation Shield warmest 150 K
Thermal Analysis Calculated Thermal Loads • Radiation shield 64 watts • Cold Structure 11 watts • Array1 0.518 watts • Array2 0.767 watts
Thermal AnalysisFEA Results • Cold Mass • T min = 67 K • T max = 73 K • Cold Shield • T min = 69 K • T max = 105 K
Thermal AnalysisDetector Cold Straps Calculated Detector temperatures • Blue Detector temperature 21.5 K (heater off) • Blue Detector temperature 23 K (heater off) • Expected heater power 1-1.8 watts to achieve detector operating temperature
Thermal Analysis Cooldown Time • Estimated Radiation Shield cooldown time 36 hours • Estimated Filter wheel cooldown 30 hours