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Thermodynamic Modeling o f Astronomical Infrared Instruments. Francesc Andre Bertomeu Hartnell College Salinas, California. Research Advisor: James Larkin Research Supervisors: Michael McElwain and Shelley Wright University of California Los Angeles.
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Thermodynamic Modeling o f Astronomical Infrared Instruments Francesc Andre Bertomeu Hartnell College Salinas, California Research Advisor: James Larkin Research Supervisors: Michael McElwain and Shelley Wright University of California Los Angeles This project is supported by the National Science Foundation Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement No. AST - 9876783.
Infrared Instrumentation and Applications Star Trek Lt. Cmdr Geordi LaForge Military http://www.ir55.com/ Astrophysics & Astronomy
Importance of Cryogenics In Astronomical Infrared Instruments Problems Astronomical targets are faint. Warm instruments are bright. Everything above zero Kelvin emits thermal radiation (including infrared light). 4. Heat = Light. Solutions Cool instruments to cryogenic temperatures Predict Thermodynamic behavior I.E. Thermodynamic Modeling
O.S.I.R.I.S. OH-Suppressing Infra-Red Imaging Spectrograph • Designed for Keck AO system • The most sensitive infrared spectrograph • OSIRIS saw first light on Feb 22-23 Well, he gave me a speeding ticket when I told him it was technically a blue-shifted light So he didn’t ticket you after running the red light?
O.S.I.R.I.S. Continued Consists of 1. Optics and detector 2. Dewar 3. Cooling System (Closed-Cycle Refrigerator) 4. Hydraulic lifting mechanism
O.S.I.R.I.S. Continued Consists of 1. Optics and detector 2. Dewar 3. Cooling System (Closed-Cycle Refrigerator) 4. Hydraulic lifting mechanism
O.S.I.R.I.S. Continued Consists of 1. Optics and detector 2. Dewar 3. Cooling System (Closed-Cycle Refrigerator) 4. Hydraulic lifting mechanism
The Thermal Model Simplified algorithm Calculate heat flow through conduction and radiation for each internal component Conduction = k(A/L) (TH - TC ) Radiation & Absorption = ;EAT4 Pwr = Net power of System 2. Determine new temperatures } Q = cm#T (J) Q(t) = Pwr*t Pwr = Q/t (J/s) Tf = (Pwr*t)/cm + Ti
The Code • Written in IDL • Passes in Variables • Results are Plotted IDL Program
My Project Update the Model to Reflect Changes Adjust Parameters to fit real Data Apply Finished Model to IRIS
My Project Update the Model to Reflect Changes • Dewar & Shields • Gold Capton • Copper Strapping (Radiation & Absorption = ;EAT4) (Conduction = k(A/L) (TH - TC ))
My Project Update the Model to Reflect Changes
My Project 2. Adjust Parameters to fit real Data
My Project 2. Adjust Parameters to fit real Data
My Project 2. Adjust Parameters to fit real Data • A/L values for Copper • Thermal Conductivity for Aluminum • Emissivity Conduction = k(A/L) (TH - TC ) Radiation & Absorption = ;EAT4
My Project 2. Adjust Parameters to fit real Data
Applications • Applied to IRIS (design phase) • 30 Meter Telescope http://www.astro.caltech.edu/observatories/tmt/renders.html
My Project 3. Applying Finished Model to IRIS • 4 X Osiris all the way around • Mass, Areas, Lengths, 4 CCR’s
Results Osiris • 234 hrs to Cool • 2 hr brown out = 25 hr recovery • 3 hr brown out = 39 hrs recovery Iris • 223 hrs to Cool • 2 hr brown out = 10 hr recovery • 3 hr brown out = 21 hrs recovery
Conclusion • Previous model was updated to reflect changes • made during construction OSIRIS • Final product was be adapted to model the behavior of • next generation of integral field spectrographs • Program is important for predicting cryogenic • behavior of cryogenic instruments.
Acknowledgements • CfAO Members and Staff • Research Advisor: James Larkin • Research Supervisors: Michael McElwain and Shelley Wright • UCLA IR Lab This project is supported by the National Science Foundation Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement No. AST - 9876783.