FLITECAM: The first light camera for SOFIA

1. FLITECAM: The first light camera for SOFIA Amanda Mainzer, I. S. McLean, T. Aliado, E. E. Becklin, G. Brims, J. Goulter, E. Kress, N. Magnone, J. Milburn, G. Skulason, M. Spencer UCLA SPIE • 27 August 2002

2. Dr. Ian McLean, Principal Investigator Amanda Mainzer, Instrument Scientist Ted Aliado, Mechanical/Fabrication Dr. Eric Becklin, SOFIA Project Scientist George Brims, Systems Engineering John Goulter, Mechanical/Regulatory Evan Kress, Mechanical Nick Magnone, Mechanical/Fabrication John Milburn, Software Gunnar Skulason, Electronics Michael Spencer, Electronics FLITECAM Team UCLA:

3. First Light Test/Experiment CAMera/ for SOFIA Features: 1- 5 µm with InSb 1024 x 1024 array FOV: 8´ diameter (inscribed on detector) Scale: 0.47´´ per pixel LHe/LN2 system Grism Spectroscopy (R~2000) Co-mounts with HIPO First light: ~Q3 2002 (ground based) Delivery to SOFIA: Q1 2004 Must be fully FAA certified Z(up) Y(side) X(aft) FLITECAMSummary

4. FLITECAM’sField of View • Originally going to use 512x512 array • Between PDR and CDR, switched to 1024x1024 array to image the entire 8 arcmin SOFIA field of view

5. Optics Modes: - Imaging - Grism (R~2000) - Pupil viewing Optical design: - Collimator triplet - F/5 imaging camera - 4 fold mirrors - Dual filter wheel - 3 pupil viewing lenses - Filters: ZJHKK’LM + selected narrow band

6. Image Quality • SOFIA seeing ~2-3 arcsec • FLITECAM PSF: • 0.2 - 0.5 arcsec across • entire 8 arcmin field of view • FLITECAM designed to fully evaluate SOFIA image quality Box = 2x2 pixels 1 pixel = 0.47 arcsec

7. ThermomechanicalOptical Design • Large crystal lenses have to be cooled in controlled fashion to avoid thermomechanical shock • Collimator: LiF, BaF2, ZnS all with diameter ~165 mm • Spring-loaded “finger” mounts isolate lenses and prevent thermomechanical shock • Lenses manufactured by Brad Picirillo of Optical Solutions Inc. of New Hampshire LiF lens Spring-loaded “fingers”

8. Thermomechanical Performance • Large LiF and BaF2 lenses particularly susceptible to thermal & mechanical shock • Spares difficult & expensive to obtain - 9 month lead time! • To verify success of our mounting/thermal isolation scheme, we constructed a dummy collimator

9. Dummy Collimator • Brad Picirillo of OSI provided spare unpolished LiF lens for dummy collimator • Put in two additional glass blanks to simulate thermal characteristics of BaF2 and ZnS lenses • Epoxied thermometers to spare LiF: front/back center, and front edge • Additional thermometers on collimator housing and optical baseplate • This allowed us to monitor gradients vs. cooldown rate 77 K end ~165 mm Glass blanks LiF spare lens Thermometers: front center, front edge, back edge

10. ThermomechanicalOptical Design cont’d. • Cooldown rates controlled by isolating selected components with G10 • Time constants calculated and measured to determine safe rates • Thanks to Brad Picirillo of OSI for providing spare LiF! • Will eventually test spare LiF to destruction • Results show that cooldown rates of up to 13 K/hr are safe! Edge to center gradient Front center to back center gradient

11. Warm First Light • To avoid long iterative cryogenic cycles, found focus warm • Confirmed warm focus with warm Zemax optical model • Warm best focus location agreed with warm focus model to within depth of focus • Set focus to predicted cold focus location

12. Completed Software • Java platform-independent • Software controls temperature sensors, vacuum gauge, helium level sensor, detector heater, and mechanisms • Astronomical Observation Requests (AORs) will be written using a modified version of SPOT (SIRTF Planning and Observation Tool)

13. Electronics • Detector head and electronics purchased from Mauna Kea Infrared • These systems are being packaged into 19” racks for ground-based operations: • Data acquisition system • Mechanism controllers • Temperature controllers • Pressure monitors • LHe level monitor • Power controller On-Cryostat Electronics Multiplexer CW Rack SHARC Processor

14. Cryogenics • LN2/LHe cryostat manufactured by Precision Cryogenics of Indianapolis, IN • 20 L of LN2, 20 L of LHe • FAA regulations: cryostat can only be filled when plane is on the ground • Will fill before each night’s observing • Cylindrical design dictated by SOFIA volume allocation • Cryostat can either look up or horizontal - can be used on ground

15. FLITECAMFAA Cryogen Container Testing • DAR witnessed testing at PCI on 28 March 2002 • LN2 Container Pressure Test • measuring the deformation of container under pressure • checking conformance with drawings

16. FLITECAM Assembly

17. CY 01 CY 02 CY 03 CY 04 2 1 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 Aircraft Structures mod. Complete Fwd Bulkhead Complete OFR Review Top Level SOFIA Milestones TA Ground Acceptance Obs. Flt. Test Done Perf. Flight Test ORR 9/28 FY01> Integration and test FLITECAM Del’y to SSMOC 3/30/04 FLITECAM Acceptance 10/1/04 FLITECAM Cryostat 8110-3 20/9/01 Design Complete Q2-01 Delivery Jan 02 Cryostat Test &Review Integration and test Delivery Aug01 Electronics Optics Delivery Q4-01 Alignment and test First Light in Lab? System Level Tests Integration and test Software Development Ongoing Software development and Validation FLITECAM/HIPO INTEGRATION FLITECAM - HIPO Integration Testing Apr 03 FLITECAM/HIPO Deployment to JAITV Jun 03 Telescope Deployment Aug 02 IT & V Phase 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 Milestones

18. Commissioning • Three fall observing runs scheduled at 3-m Shane Telescope at Lick Observatory • Shane telescope’s F/17 optics well-matched to SOFIA’s F/19.6 • First run starts Sept. 13! • Will observe a variety of star forming regions • Observations will constitute part of A. Mainzer’s Ph.D. thesis